U.S. patent number 3,616,157 [Application Number 04/848,502] was granted by the patent office on 1971-10-26 for embossed nonwoven wiping and cleaning materials.
This patent grant is currently assigned to Johnson & Johnson. Invention is credited to J. Harold Smith.
United States Patent |
3,616,157 |
Smith |
October 26, 1971 |
EMBOSSED NONWOVEN WIPING AND CLEANING MATERIALS
Abstract
An embossed nonwoven fabric having a textured character and
fabriclike qualities of softness and hand and suitable for wiping
surfaces having aqueous and/or oleaginous liquids and/or more
viscous semisolids thereon comprising a web containing at least one
layer of overlapping, intersecting fibers, a pattern of
intermittantly spaced, embossed, compacted or densified fibrous
areas lying in the planes of both surfaces of said web of
overlapping, intersection fibers, and a pattern of unembossed,
uncompacted fibrous portions lying between said planes and
connecting said embossed, compacted fibrous areas.
Inventors: |
Smith; J. Harold (Amherst,
MA) |
Assignee: |
Johnson & Johnson
(N/A)
|
Family
ID: |
25303455 |
Appl.
No.: |
04/848,502 |
Filed: |
August 8, 1969 |
Current U.S.
Class: |
428/171;
15/229.12; 264/286; 428/196 |
Current CPC
Class: |
D04H
1/558 (20130101); A47L 13/16 (20130101); Y10T
428/24603 (20150115); Y10T 428/2481 (20150115) |
Current International
Class: |
A47L
13/16 (20060101); D04H 1/74 (20060101); D04H
1/70 (20060101); D04H 1/00 (20060101); A71 (); B32b
003/00 () |
Field of
Search: |
;161/124,125,123,130,131,128,132,133,135,146,148,170
;162/109,113,115,116,117 ;156/183,205,209 ;264/257,284,293,286
;15/209,210 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Powell; William A.
Claims
What is claimed is:
1. An embossed nonwoven fabric having a textured character and
fabriclike qualities of softness and hand and suitable for wiping
surfaces having aqueous or oleaginous liquids or more viscous
semisolids thereon comprising a fibrous web containing at least one
layer of overlapping, intersecting fibers, a pattern of
intermittently spaced, embossed compacted fibrous areas lying in
the planes of both surfaces of said web of overlapping,
intersecting fibers, and a pattern of unembossed, uncompacted
fibrous portions lying between said planes and connecting said
embossed, compacted fibrous areas. An embossed nonwoven fabric as
defined in claim 1 wherein the embossed compacted fibrous areas are
in the form of
polygons. 3. An embossed nonwoven fabric as defined in claim 1
wherein the
embossed compacted fibrous areas are in the form of squares. 4. An
embossed nonwoven fabric as defined in claim 1 wherein the
embossed
compacted fibrous areas are in the form of diamonds. 5. An embossed
nonwoven fabric as defined in claim 1 wherein the embossed
compacted fibrous areas cover from a fraction of 1 percent to about
90 percent of
the surfaces of each side of said embossed nonwoven fabric. 6. An
embossed nonwoven fabric as defined in claim 1 wherein the embossed
compacted fibrous areas cover from about 10 percent to about 40
percent of the
surfaces of each side of said embossed nonwoven fabric. 7. An
embossed nonwoven fabric as defined in claim 1 wherein the embossed
compacted fibrous areas are substantially the same on each side of
said embossed
nonwoven fabric whereby the surface coverages thereof are the same.
8. An embossed nonwoven fabric as defined in claim 1 wherein the
embossed compacted fibrous areas are different on each side of said
embossed
nonwoven fabric whereby the surface coverages thereof are
different. 9. An embossed nonwoven fabric as defined in claim 1
wherein the embossed compacted fibrous areas are compacted to
substantially the same degree of
compaction. 10. An embossed nonwoven fabric as defined in claim 1
wherein the embossed compacted fibrous areas are compacted to
different degrees of
compaction. 11. An embossed nonwoven fabric as defined in claim 1
wherein the intermittently spaced, embossed compacted fibrous areas
lying in the plane of one surface of said web are connected to the
intermittently spaced, embossed compacted fibrous areas lying in
the plane of the other
surface of said web by channels of embossed compacted fibrous
areas. 12. An embossed nonwoven fabric having a textured character
and fabriclike qualities of softness and hand and suitable for
wiping surfaces having aqueous or oleaginous liquids or more
viscous semisolids thereon comprising a carded fibrous web
containing at least one layer of overlapping, intersecting fibers,
a pattern of intermittently spaced, embossed compacted fibrous
areas lying in the planes of both surfaces of said web of
overlapping, intersecting fibers, and a pattern of unembossed,
uncompacted fibrous portions lying between said planes and
connecting said
embossed, compacted fibrous areas. 13. An embossed nonwoven fabric
having a textured character and fabriclike qualities of softness
and hand and suitable for wiping surfaces having aqueous or
oleaginous liquids or more viscous semisolids thereon comprising a
fibrous web containing at least one layer of overlapping,
intersecting fibers, a pattern of intermittently spaced, embossed
compacted fibrous areas lying in the planes of both surfaces of
said web of overlapping, intersecting fibers, and a pattern of
unembossed, uncompacted fibrous portions lying between said planes
and slantingly and angularly connecting said embossed, compacted
fibrous
areas. 14. An embossed nonwoven fabric having a textured character
and fabriclike qualities of softness and hand and suitable for
wiping surfaces having aqueous or oleaginous liquids or more
viscous semisolids thereon comprising a fibrous web containing at
least one layer of overlapping, intersecting fibers, a pattern of
intermittently spaced, embossed compacted fibrous areas lying in
the planes of both surfaces of said web of overlapping,
intersecting fibers, said planes being substantially parallel but
offset with respect to each other, and a pattern of unembossed,
uncompacted fibrous portions lying between said substantially
parallel but offset planes and connecting said embossed, compacted
fibrous
areas. 15. An embossed nonwoven fabric having a textured character
and fabriclike qualities of softness and hand and suitable for
wiping surfaces having aqueous or oleaginous liquids or more
viscous semisolids thereon comprising a fibrous web containing at
least one layer of overlapping, intersecting fibers, said layer
being so embossed that a portion of one surface thereof lies in one
plane and a portion of its other surface lies in a substantially
parallel but offset plane with respect to the first plane, a
pattern of intermittently spaced, embossed compacted fibrous areas
lying in the planes of both surfaces of said web of overlapping,
intersecting fibers, and a pattern of unembossed, uncompacted
fibrous portions lying between said planes and connecting said
embossed, compacted fibrous areas.
Description
This invention relates to nonwoven fabrics and more particularly to
embossed nonwoven fabrics having improved wiping rates or cleaning
efficiencies and well suited as wiping or cleaning materials for
surfaces having aqueous and/or oleaginous liquids and/or more
viscous semisolids thereon.
In the past, nonwoven fabrics comprising at least one layer of
overlapping, intersecting fibers have been used as wiping and
cleaning materials for aqueous and/or oleaginous liquids and/or
more viscous semisolids, such as water, syrups, aqueous solutions,
chemicals, oils, fats, waxes, greases, cosmetics, etc. and have met
with considerable commercial success. However, it is always
desirable to improve the properties and characteristics of existing
commercial products and, in the case of wiping and cleaning
materials, to enhance their wiping rates and cleaning
efficiencies.
Typical examples of nonwoven fabrics which are suitable for wiping,
cleaning, and related purposes are noted in U.S. Pat. Nos.
2,039,312, 2,676,364, 2,705,688, 2,862,251, and 2,834,703. It is a
primary purpose of the present invention to improve the wiping
rates and cleaning properties and characteristics of such nonwoven
fabrics and like materials.
It has been discovered that such a purpose may be achieved by
embossing or compacting the layer or layers of overlapping,
intersecting fibers which form the nonwoven fabrics or the like in
such a way that the embossed or compacted areas lie in the planes
of both top and bottom surfaces of such nonwoven fabrics and
therefore directly contact the liquids or semisolids to be wiped or
cleaned. Such has been found to improve the fluid absorbency and
retentivity of the nonwoven fabric and to enhance its wiping and
cleaning efficiency. Also, and perhaps more importantly, the
wetting rate is enhanced due to the compacted structure of the
embossed areas which provide capillarity, coupled with avenues of
rapid liquid flow into the body of the nonwoven fabric.
It has further been discovered that a textured character and
fabriclike qualities of softness and hand as well as loft,
resiliency, and drape may be retained in the embossed, compacted
nonwoven fabrics if the embossing or compacting takes place
intermittently in spaced, discrete areas on both surfaces of the
nonwoven fabric and wherein unembossed or uncompacted portions
having high loft and bulk lie between the planes of the surfaces of
the nonwoven fabrics and connect the embossed, compacted areas.
The embossed area must not cover the entire surface of each side of
the nonwoven fabric. Such overall embossing or compacting will
yield a stiff, boardy wiping fabric which is entirely undesirably
and unsatisfactory. The embossed, compacted areas must therefore be
interrupted by other areas which are not embossed or compacted, or
by voids or gaps in the planar surface of the nonwoven fabric. In
the event that the compacted areas join one another to form an open
network or interconnected grid, such is to be considered as spaced
or interrupted embossed areas, provided they meet the other
requirements set forth in this specification.
To more clearly define the nature of the present invention,
reference is made to the following specification and accompanying
drawings wherein there are described and illustrated preferred
embodiments of the invention. This is intended primarily to
disclose the invention more fully but not to limit it. With
reference to the accompanying drawings:
FIG. 1 is an idealized, fragmentary cross-sectional view of
embossing plates or embossing rolls such as were used in the prior
art for embossing nonwoven fabrics;
FIG. 2 is an idealized, fragmentary cross-sectional view of an
embossed nonwoven fabric of the prior art resulting from the use of
the embossing plates or embossing rolls of FIG. 1;
FIG. 3 is an idealized, fragmentary cross-sectional view of the
improved embossing plates or embossing rolls, taken on the line
3--3 of FIGS. 5 and 6, as are used in applying the principles of
the present invention;
FIG. 4 is an idealized, fragmentary cross-sectional view of an
embossed nonwoven fabric, taken on the line 4--4 of FIG. 7,
resulting from the use of the embossing plates or embossing rolls
of FIG. 3;
FIG. 5 is an idealized, fragmentary perspective view of a portion
of parts of a pair of mating embossing plates used to make the
improved embossed nonwoven fabrics of the present invention;
FIG. 6 is an idealized, fragmentary plan view of the mating
embossing plates of FIG. 5, disclosing the spatial relationship of
the embossing lands of both embossing plates;
FIG. 7 is an idealized, fragmentary perspective view of a portion
of an improved embossed nonwoven fabric of the present invention
resulting from the use of the embossing plates of FIGS. 5 and
6;
FIG. 8 is an idealized, fragmentary plan view of a modified form of
mating embossing plates having circular embossing lands of use in
the application of the principles of the present invention.
FIG. 9 is an idealized, fragmentary cross-sectional view of a
modified form of mating embossing plates, taken on the line 9--9 of
FIG. 12, showing embossing lands of different size and having
different compacting forces of use in the application of the
principles of the present invention;
FIG. 10 is an idealized, fragmentary plan view of a modified form
of mating embossing plates having a diamond-embossing grid and
diamond-shaped embossing lands of use in the application of the
present invention;
FIG. 11 is an idealized, fragmentary schematic view in elevation
showing the use of rotatable embossing rolls of use in the
application of the principles of the present invention;
FIG. 12 is an idealized, fragmentary plan view of the mating
embossing plates of FIG. 9, disclosing the spatial relationship of
the embossing lands of the mating embossing plates;
FIG. 13 is an idealized, fragmentary plan view of a variation of
the mating embossing plates of FIGS. 9 and 12 but disclosing a
variation in the sizes of the embossing lands of the mating
embossing plates;
FIG. 14 is an idealized, fragmentary plan view of a variation of
the mating embossing plates of FIGS. 9 and 12 but disclosing
another variation in the sizes of the embossing lands of the mating
embossing plates;
FIG. 15 is an idealized, fragmentary plan view of a modified form
of mating embossing plates having diamond-shaped embossing lands on
one surface and a grid plate formed with circular holes as the
embossing land of the cooperating embossing surface;
FIG. 16 is an idealized, exploded, fragmentary cross-sectional view
taken on the line 16--16 of FIG. 15 showing the mating embossing
plates and the embossed wiping cloth resulting from the operation
of such mating embossing plates;
FIG. 17 is an idealized, fragmentary perspective view of a
modification of the pair of mating embossing lands such as
illustrated in FIG. 5 but disclosing an additional technique for
forming embossed compacted channels between the embossed areas in
one surface of the nonwoven fabric and the embossed areas in the
other surface of the nonwoven fabric; and
FIG. 18 is a further modification of the channel-forming techniques
of FIG. 17 but showing embossed compacted fibrous channels at all
four corners of the embossed areas of the embossed nonwoven
fabric.
Embossed nonwoven fabrics for various purposes are well known in
the textile and related industries, as noted in U.S. Pat. No.
2,834,703 and particular reference is made to FIG. 3 of this patent
showing a specific embossed nonwoven fabric for cosmetic and
related purposes. In the methods disclosed in this prior art
patent, embossing plates or embossing rolls having mating surfaces
or lands such as illustrated in cross section in FIG. 1 of this
specification are used and an idealized cross section of the
resulting embossed nonwoven fabric is illustrated in FIG. 2 of this
specification.
It is to be appreciated that, when the embossed, nonwoven fabric of
FIG. 2 of this specification is used for wiping or cleaning
purposes, the unembossed, uncompacted areas which extend beyond the
plane of the nonwoven fabric come into more intimate contact with
the surface to be wiped or cleaned than do the embossed, compacted
areas which lie in the plane of the nonwoven fabric. This results
in a wiping or cleaning action which has been found acceptable in
the prior art but which is improved by use of the principles of the
present invention.
According to the principles of the present invention, the formation
and basic construction of the embossing plates or embossing rolls
is modified whereby a novel, improved embossed nonwoven fabric is
obtained. As shown in FIG. 3 of this specification, upper and lower
mating, embossing plates 10 and 12 are used wherein the respective
embossing lands 14, 16 and 18, 20 are parallel but offset with
respect to each other and to the plane of web 11 of one or more
layers of overlapping, intersecting fibers constituting a nonwoven
fabric, whereby the compacted areas 22, 24 (See FIG. 4) of the
resulting embossed nonwoven fabric 26 are similarly parallel but
offset.
Also, as noted in FIG. 4, fibrous portions 28, 30 extend slantingly
and angularly from the intermittently spaced embossed, compacted
fibrous areas 22 lying in one surface of the nonwoven fabric 26 to
the intermittently spaced, embossed, compacted fibrous areas 24
lying in the other surface of the nonwoven fabric 26. These fibrous
portions 28, 30 are unembossed and uncompacted and retain their
original softness, bulk, and loft and provide fabriclike qualities
of softness and hand, as well as loft, resiliency and drape to the
embossed nonwoven fabric 26.
The compacted areas 22 and 24 thus form a pattern of intermittently
spaced, separate and discrete, embossed, compacted fibrous areas
which lie in the planes of the substantially parallel top and
bottom surfaces of the nonwoven fabric, whereas the unembossed,
uncompacted portions 28, 30 lie between these planes and hingedly
connect the embossed, compacted areas. With such a configuration,
it is to be appreciated that, when the embossed, nonwoven fabric 26
of FIG. 4 is used for wiping or cleaning purposes, an entirely new
principle and cleaning action is involved wherein the compacted
areas 22, 24 come into more intimate contact with the surface to be
wiped or cleaned than do the uncompacted areas 28, 30. As will be
pointed out hereinafter, such principles result in an enhancement
of the wiping and cleaning efficiency.
It is to be pointed out, moreover, that the compacted areas have
superb liquid-wiping efficiency and act in the fashion of wiping
blades or barriers which "snowplow" liquids, greases, and
semisolids. Also, the "pockets" or voids 29 (See FIG. 4) in the
structure of the nonwoven fabric hold the grease or other materials
being wiped out of direct pressing contact with the surface being
wiped.
In FIG. 5, there is illustrated one form of the lower embossing
plate 12 capable of making one typical embosidment of the embossed
nonwoven fabric of the present invention. The embossing surfaces or
lands 16 of the lower embossing plate 12 are squares and are
arranged in substantially parallel-spaced checkerboard rows. The
upper embossing plate 10 which possesses substantially
parallel-spaced checkerboard rows of embossing surfaces or lands 18
is shown fragmentarily, in order to avoid confusing FIG. 5, but its
action and mating embossing function with the lower embossing plate
12 is obvious.
FIG. 6 discloses a plan view of the spatial relationship of the
embossing lands 16 and 18 of the lower and upper embossing plates
12 and 10, respectively. The intermittent spacing and arrangement
of these lands is such that one pair of lands (14, 16, for example)
forces the nonwoven fabric in one direction to be compacted in one
surface of the nonwoven fabric whereas an adjacent pair of lands
(18, 20 for example) forces the nonwoven fabric in the other
direction to be compacted in the other surface of the nonwoven
fabric.
The resulting three-dimensional, embossed effect is well
illustrated in FIG. 7. It is to be appreciated, however, that such
an effect is the result of having embossing lands with mating
square cross sections. Such specific cross sections are merely
illustrative of the present invention. Other geometric shapes and
figures may, of course, be used, and include, for example,
polygons, including triangles, rectangles, diamonds, pentagons,
hexagons, octagons; curved figures such as circles, ellipses,
ovals, etc., or combinations thereof. Irregular figures and designs
may also be used such as hearts, stars, or even symbols or insignia
such as fleur-de-lis, crowns, coronets, etc.
Patterns in the forms of grids or interconnected lines which may be
continuous or discontinuous, narrow or broad, straight or wavy, may
be used. Their general direction or orientation may be in the
machine or long direction, parallel to the predominant fiber
orientation, if a card web is used, or they may be in the cross or
short direction, perpendicular to the predominant fiber
orientation, or they may be diagonally or angularly positioned, as
desired or required.
FIG. 8 discloses the spatial arrangement of circular geometric
figures 32, 34 as the mating embossing lands; other arrangements
and the use of other shapes or figures are also of use. These are
not shown in the drawings as their arrangement and use is believed
clear.
It is not essential that the same geometric shape or figure be used
on each side of the nonwoven fabric. Nor is it essential that the
same amount of surface coverage of compacted area be present on
each side of the nonwoven fabric. For example, FIG. 9 discloses a
cross section of mating, embossing plates 36 and 38 wherein large
rectangular embossed, compacted areas 40 are formed on one surface
of the nonwoven fabric 41 and small rectangular embossed, compacted
areas 42 are formed on the other surface of the nonwoven fabric 41.
Unembossed or uncompacted fibrous portions 44 and 46 are noted as
lying between the top and bottom surfaces of the nonwoven fabric
and angularly and slantingly join the compacted areas 40, 42 in a
hinged relationship.
The relative size and relationship of the embossing lands of the
mating, embossing plates 36 and 38 is more clearly illustrated in
FIG. 12 and reference thereto will indicate that the small embossed
areas 42 are formed by the small lands 116 which are approximately
one-quarter the dimensions of the large lands 118 which form the
large embossed areas 40. As a result, the total area of the small
embossed area 42 is only one-sixteenth of the total area of the
large embossed area 40.
The relative size and spatial relationship of the lands of the
cooperating mating, embossing plates or lands may be varied widely
depending on the needs or requirements of the particular situation.
For example, in FIG. 13, there is illustrated a pair of embossing
lands 216 and 218 which vary in relative size to a greater degree
than the previous pairs of lands shown in FIG. 12.
In FIG. 14, the variation in size of the pair of lands 316 and 318
is increased to even a greater degree. Also, it is to be noted that
the shapes of the lands have been varied from the previous
square-square relationship to a square-rectangle relationship.
FIG. 10 discloses a simplified plan view of mating embossing plates
whereby diamond-shaped compacted areas are capable of being formed
on one surface of the nonwoven fabric by means of diamond-shaped
lands 50 and a relatively thin diamond grid of compacted lines is
capable of being formed in the other surface of the nonwoven fabric
by a corresponding relatively thin diamond-grid land 52. This, of
course, results in different patterns on each surface of the
resulting nonwoven fabric.
The diamond-shaped lands 50 are, of course, integral with one
member of a pair of cooperating mating embossing plates and the
diamond-grid land 52 is, of course, integral with the other member
of the pair of cooperating mating embossing plates.
The majority of these geometric figures can be produced by machine
shop milling procedures. However, in the event that such procedures
are difficult or uneconomical to carry out for a particular shape
or figure, then other known techniques are readily available in the
art. Such other techniques include engraving, etching,
electrodeposition, perforated plate sleeves, etc.
Regardless of the shape, form or number of geometric figures which
are involved, it is essential that there be a pattern of
intermittently spaced, separate, discrete embossed compacted areas
in at least one plane of the surfaces of the nonwoven fabric. Such
a configuration will insure the positioning of the compacted
densified areas where desired and will also insure that the
unembossed, uncompacted portions do not lie in the planes of the
surfaces of the nonwoven fabrics or extend beyond such planes but
lie between these planes and do not directly contact the surfaces
to be cleaned.
FIGS. 15 and 16 illustrate the use of a rather unusual pair of
cooperating, mating, embossing plates 90 and 92. Plate 90 is formed
from a platelike member 91 from which a plurality of circular holes
94 have been removed, for example, by drilling. The holes are
aligned in parallel rows which nest or fit together in a staggered
relationship as seen in FIG. 15. It is to be appreciated that the
surface or area 104 around the circular holes 94 actually forms the
embossing lands of plate 90. The apertured platelike member 91 is
relatively thin and is secured to a base 93 and the two elements
form one member of the pair of cooperating mating embossing plates
90 and 92.
The other member of the pair of cooperating mating embossing plates
is the plate 92 which possesses a plurality of diamond-shaped lands
96 which are so positioned that they are aligned with the circular
holes 94 and can be moved reciprocatingly within the space created
by these circular holes.
Consideration of FIG. 16 will reveal that diamond-shaped lands 96
will cooperate with the opposed surfaces 98 of baseplate 93 to form
an embossed compacted fibrous area 100 in the nonwoven fabric 102.
Also, at the same time, the upper surface 104 of the embossing
plate 90 will cooperate with the opposed surface 106 of the mating
embossing plate 92 to form embossed compacted fibrous areas 108 of
the nonwoven fabric 102. Again, it is to be noted that a pattern of
unembossed, uncompacted fibrous portions 110 and 112 are formed and
that they are within the plane of the embossed nonwoven fabric and
hingedly and slantingly connect the embossed areas 100 and 108 in
the same way as described previously.
The result of such application of the principles of the present
invention will yield a two-faced fabric. One side will have a
series of intermittently spaced, discrete diamond-shaped embossed
areas, whereas the other side will have a compacted area
corresponding to that of the surface of plate 91.
Embossing plates which reciprocate rectilinearly in their embossing
action have been found to be capable of satisfactory use and have
many advantages. However, the use of rotatable embossing rolls is
desirable in many instances, particularly where large scale
manufacturing production is involved.
In FIG. 11, there is illustrated a typical arrangement involving
the use of rotatable mating embossing rolls 60, 62. Projections or
embossing lands 64, 66 extend from the surfaces of the rolls 60,
62, respectively, somewhat generally resembling gear teeth, and
cooperate with the surfaces 68, 70, respectively, of the opposed
rolls 62, 60. In this way, a plurality of webs of overlapping,
intersecting fibers constituting a substantially flat nonwoven
fabric 72 is introduced between the embossing lands and opposed
surfaces and is embossed in an offset manner as described herein.
This yields compacted areas 74, 76 which lie in the planes of the
surfaces of the nonwoven fabric 72 and are connected hingedly and
angularly by unembossed and uncompacted portions 78, 80. The
compacted areas are intermittently spaced not only radially by the
embossing rolls which is equivalent to a lengthwise direction of
the nonwoven fabric but they may also be intermittently spaced
axially by removing portions of the projections 64, 66 at regularly
spaced location in an axial direction. This intermittently spaces
the compacted areas in a widthwise direction of the nonwoven
fabric. Squares, diamonds, and rectangles would be the most common
form of embossing lands employed on such rotatable rolls, although
any geometric shape or figure is possible.
In the embodiments of the invention described and illustrated thus
far, the compacted fibrous areas in one plane of the nonwoven
fabric are separate and distinct from the compacted fibrous areas
in the other plane of the nonwoven fabric. This is usually
desirable but in some cases it may be desired to connect them with
relatively narrow, fibrous channellike members which are also
embossed or compacted whereby fluid flow therealong is
expedited.
One method of accomplishing this is illustrated in FIG. 17 wherein
the principle is illustrated in the formation of merely one
channellike member. In this Figure, the nonwoven fabric being
embossed is omitted for purposes of clarity. A pair of adjacent
embossing lands 416 and 418 are shown and it is to be appreciated
that upward relative movement of land 416 will form a compacted or
embossed fibrous area on its upper surface. At the same time,
downward relative movement of land 418 will form a compacted or
embossed fibrous area on its lower surface. Such has been described
previously. These compacted areas would normally not be connected.
However, a pair of channel-forming lands 420 and 422 are formed
adjacent to and integral with the lands 416 and 418, respectively,
and have sloping surfaces 424 and 426 which oppose each and come
together to emboss or compact a slanting channellike fibrous
compacted strip which extends angularly between the embossed areas
in the surface of the nonwoven fabric.
FIG. 18 discloses the application of such channel-forming
techniques to a nonwoven fabric 430. Four square-shaped compacted
areas 432 are shown which exist in one plane of one surface of the
nonwoven fabric 430. One square-shaped compacted area 434 is shown
which exists in the other plane of the other surface of the
nonwoven fabric 430. Four channellike members 436, 438, 440 and 442
are shown connecting all these compacted areas, whereby fluid flow
between these areas is facilitated and expedited.
The degree of compaction or the amount to which the fibrous areas
can be densified is controlled and regulated by the clearance
between the embossing lands and the opposed embossing surfaces. A
moderate compaction yields excellent wiping and capillarity along
with good resilience, softness and hand. Heavier compaction
facilitates bonding characteristics where such properties are of
interest, particularly if any potentially softenable and fusible
thermoplastic fibers or materials are used. Reference to FIG. 9
will reveal that the degree of compaction need not necessarily be
the same on both sides of the nonwoven fabric but may be different.
The degree of compaction is controlled and regulated by changing
the clearances between the embossing lands and the cooperating
opposed embossing surfaces.
In FIG. 9, the embossing lands and cooperating opposed embossing
surfaces are closer together in the formation of the small embossed
area 42 than are the embossing lands and cooperating opposed
embossing surfaces which form the large embossed area 40. As a
result, the embossed area 42 is much more compacted and bonded
together than the embossed area 40.
The compression forces required to obtain the degree of compaction
required will vary widely within the principles of the present
invention. Compression forces of from about 100 pounds per square
inch to about 10,000 pounds per square inch have been found
satisfactory. However, from about 100 to about 1,000 pounds per
square inch is preferred as such avoids the destructive effects of
crushing and cutting occasionally noted at very high pressures for
some patterns. The time intervals for the application of such
compressive forces will also vary widely and, within the principles
of the present invention, good results are obtainable using
application times of approximately one two-hundredth of a second to
about one one-hundredth of a second or more. Such a time interval
is also classifiable as substantially instantaneous. If it is
desired to apply the compressive forces at elevated temperatures,
such may be done at temperatures of from about 212.degree. F. to
about 450.degree. F., with preferable limits being from about
250.degree. F. to about 350.degree. F.
Normally, the natural moisture regain of the cellulosic fibers is
sufficient in order to obtain satisfactory results. Such natural
moisture regain is normally in the area of from about 6 percent to
about 10 percent. On occasion, if it is desired, additional
moisture may be applied to bring the moisture content up to 30
percent or 60 percent, or even more, where additional moisture and
compaction is desired.
The amount of surface coverage of the compacted areas in the planes
of the surfaces of the nonwoven fabric may vary widely and, as
pointed out herein with particular reference to FIG. 9 and 10, need
not be equal. Within the broader aspects of the present invention,
however, the surface coverage of the compacted area on each side of
the nonwoven fabric may be as low as a fraction of 1 percent and as
high as about 90 percent. Within the narrower and more preferred
aspects, however, the surface coverage of the compacted areas on
each side of the nonwoven fabric is in the range of from about 10
percent to about 40 percent.
By a judicious selection of the shape of the geometric pattern for
each side of the nonwoven fabric and by varying the amount of
surface coverage for each side, different properties and
characteristics can be created in each side whereby a two-sided
product is obtained with a different function or use for each
side.
The nonwoven fabrics of the present invention normally comprise
fibrous materials of a cellulosic origin inasmuch as the fluid
absorbency and retentivity of such fibrous materials is best suited
for the purpose of the present invention. Cotton fibers, rayon,
cotton linters, wood pulp, and the like are exemplary of such
cellulosic materials. When the fiber length of such materials is
very short, as in the case of cotton linters or woodpulp fibers,
and create difficulties in handling and processing, they are
preferably either mixed in varying proportions with fibers of
greater length and thus handled and processed, or they may form the
central layer of a three layer sandwich in which the two outer
layers comprise longer fibers.
Other fibers, such as polyolefinic, polyester, nylon 6 or 66,
acrylics, modacrylics, fluorocarbon, spandex, acetate, etc. or
other natural fibers such as wool, silk, etc., may be used in
varying percentages, from about 5 percent by weight up to about 25
percent by weight, or even more, where special properties or
characteristics are desired in the final product. The thermoplastic
fibers noted above are of use particularly if some degree of
softening and thermoplastic fusion is desired.
The nonwoven fabrics of the present invention comprise one or more
layers of overlapping, intersecting fibers and are preferably
derived from card webs wherein the individual fibers are relatively
more oriented in the long or machine direction. However, they may
also be prepared by various air-laying techniques or similar
processes whereby the nonwoven fabric is relatively more
isotropic.
The nonwoven fabrics may be processed according to the principles
of the present invention in an unbonded state, or, if desired, they
may be lightly bonded by any of the many known bonding agents
common in the nonwoven industry and then embossed in such lightly
bonded condition.
The embossing and compacting may take place with the nonwoven
fabrics in relatively dry condition, that is, merely containing the
natural moisture regain which under normal conditions is about 6-10
percent by weight but in some cases may range up to about 20
percent by weight under conditions of high humidity and high
temperature. If desired, some additional moisture or steaming up to
60 percent moisture or more may be resorted to in order to obtain a
greater set in the embossed compacted areas.
The embossing plates or rolls may be operated at room temperatures
or at elevated temperatures, if desired, and temperatures up to
212.degree. F. or even as high as 450.degree. F. may be employed to
accentuate the set of the fibers and to improve their shape
retention. Such elevated temperatures may also be restored to if
thermoplastic fusible fibers are included and it is desired to
obtain some degree of fiber softening and fusing thereof.
A light spray of a resin or other coating or impregnant may be
applied by roller or padding techniques to the embossed, compacted
nonwoven fabric, after embossing, preferably only on the embossed,
compacted areas to enhance the shape-stability of the embossed
nonwoven fabric. Too heavy a resin treatment, particularly on the
unembossed, uncompacted portions, would be undesirable for many
purposes, particularly when softness, drape and hand are desired in
the final product.
The resin or other coating which is applied to the nonwoven fabric
after embossing need not necessarily be applied to both sides. If
desired, it may be applied only to one side or, if desired, two
different resins or coatings may be applied whereby a two-sided
product is obtained. For example, a gritty or abrasive binder may
be applied to one side and a soft and yielding binder may be
applied to the other side whereby a "scrubber-wiper" nonwoven
fabric is obtained.
If desired, the nonwoven fabrics may be strengthened by the
inclusion therein of reinforcing fabrics or other structures, such
as, gauze, woven or nonwoven scrim, warp sheets, plastic screening
or netting, and the like. Again, the addition of such materials
would depend upon the requirements and needs of the particular
situation.
The nonwoven fabrics of the present invention vary widely in
weight. The minimum weight is dictated by the amount of fibers
required to form a web or sheet which can be handled during
subsequent processing. As such, web weights may be as low as about
170 grains per square yard but normally fall in the area of at
least about 400 grains per square yard. The upper limit is dictated
by the particular fabric requirements involved and normally range
up to about 1,200 grains per square yard. Heavier weights are, of
course, possible, depending upon the particular circumstances
involved.
The invention will be further described in greater detail by
reference to the following examples wherein there are set forth
specific embodiments of the invention which are intended to
illustrate the concepts involved but not to limit the same.
In the following Examples, reference will be made to wiping rates
of various fabrics. These are the results of comparative tests and
are obtained as follows: a rotatable turntable having a diameter of
20 inches and somewhat generally resembling a record player
turntable is made of the surface to be wiped, usually plateglass. A
thin film of the aqueous or oleaginous material to be wiped is
applied to the surface of the turntable such as by a multiroll
applicator to insure even, controlled film application. If the film
is clear and colorless, a dye may be added to make it visible. The
wiping fabric is then placed on the turntable and a known weight is
placed on the fabric to insure a known constant wiping pressure
against the turntable. The turntable is then rotated at a constant
speed (r.p.m.) and the rapidity of wiping the surface clean or the
wiping rate is determined by direct observation. The results do not
represent absolute values; they are all relative values but they do
represent true and reproducible comparisons between different
wiping fabrics.
EXAMPLE I
A pair of cooperating mating embossing plates as illustrated in
FIGS. 5 and 6 is prepared to the following specifications: 5
grooves per inch, cut in two directions at right angles; groove
width is 0.125 inch; groove depth is 0.0625 inch; land width is
0.075 inch; top and bottom mating embossing plates are identical
and mated as shown. There are 25 squares per square inch in each
plate; each square having an area of 0.005625 square inches. The
surface coverage of each set of lands is 14.1 percent. The fabric
of FIG. 7 is prepared.
These mating embossing plates are used to emboss an unbonded
woodpulp-filled card web sandwich comprising outer layers of
slightly prebonded KEYBAK rearranged apertured nonwoven rayon card
webs each weighing 125 grains per square yard and a centrally
located woodpulp layer weighing 350 grains per square yard, thus
making a total weight of 600 grains per square yard.
Comparison of the wiping rate of such an embossed wiping fabric
with a nonwoven fabric which is identical in all respects thereto
except that it is not embossed reveals that the embossed wiping
fabric has a twofold improved wiping rate over the unembossed
wiping fabric for a water film on a glass surface. The wiping rate
of the embossed wiping fabric is substantially improved twofold
over an unembossed wiping cloth for wiping an oil film on a glass
surface.
EXAMPLE II
A pair of cooperating mating embossing plates as illustrated in
FIGS. 15 and 16 is prepared to the following specifications: the
circular holes are drilled in a plate member to five-sixteenths
inch (0.3125 inch) diameters and are aligned with one-sixteenth
inch (0.0625 inch) spacing between adjacent aligned circular holes.
Horizontal alignment, from right to left, as noted in FIG. 15 is
involved here. As a result, there are 20 circular holes per 7.50
inches of plate member, or 2.67 circular holes per inch in one
direction. In the other direction, which is vertical, from top to
bottom, as viewed in FIG. 15, due to the 60.degree. nesting or
staggered relationship of the circular holes, there are 20 circular
holes per 10.875 inches of plate member, or 2.92 circular holes per
inch. As a result, there are a total of 7.8 circular holes per
square inch of plate member. The area of each circular hole is
0.0767 square inch. This creates a total area of the circular holes
of 0.60 square inch per square inch of plate. The embossing area of
the perforated drilled plate is therefore 1 square inch less 0.60
square inch or 40 percent.
With regard to the diamonds, there are also 7.8 diamond lands per
square inch and each diamond has a long diagonal of about 0.30 inch
and a short diagonal of about 0.173 inch with an apex angle of
about 60.degree.. The area of a diamond is therefore 0.0263 square
inch and the total embossing area for 7.8 diamonds per square inch
is 0.205 square inch or 20.5 percent.
These mating embossing plates are used to emboss an unbonded
woodpulp-filled card web sandwich comprising outer layers of KEYBAK
rearranged apertured nonwoven rayon card webs each weighing 125
grains per square yard and a centrally located woodpulp layer
weighing 350 grains per square yard, thus making a total weight of
600 grains per square yard.
Comparison of the wiping rate of such an embossed wiping fabric
with a nonwoven fabric which is identical in all respects thereto
except that it is not embossed reveals that with regard to usage on
the perforated drilled plate side, the embossed wiping fabric has a
3.5 fold improved wiping rate over the unembossed wiping fabric for
a water film on a glass surface. With regard to usage on the
diamond embossed side, the improvement is fivefold. The wiping rate
of the embossed wiping fabric is substantially improved over an
unembossed wiping cloth for wiping an oil film on a glass surface.
On the diamond side, the improvement is sixfold; on the perforated
plate side, the improvement is over ninefold.
EXAMPLE III
A pair of cooperating mating embossing plates as illustrated in
FIG. 10 is prepared to the following specifications: the long
diagonal of the diamond land is approximately seven-sixteenths inch
and the short diagonal is approximately five-sixteenths inch. The
area of one diamond is 0.0683 square inch and, since there are 5.48
diamonds per square inch, the total embossing area in 1 square inch
of plate due to the diamond lands is 0.373 square inch or an
embossing area of 37.3 percent of the plate surface.
With regard to the embossed area created by the grid, the embossing
area is 34.5 percent.
These mating embossing plates are used to emboss an unbonded
woodpulp-filled card web sandwich comprising outer layers of KEYBAK
rearranged apertured nonwoven rayon card webs each weighing 125
grains per square yard and a centrally located woodpulp layer
weighing 350 grains per square yard, thus making a total weight of
600 grains per square yard.
Comparison of the wiping rate of such an embossed wiping fabric
with a nonwoven fabric which is identical in all respects thereto
except that it is not embossed reveals that, with regard to usage
on the diamond embossed side, the embossed wiping fabric has over a
fourfold improved wiping rate over the unembossed wiping fabric for
a water film on a glass surface. With regard to usage on the grid
embossed side, the improvement is over fivefold. The wiping rate of
the embossed wiping fabric is substantially improved over an
unembossed wiping cloth for wiping an oil film on a glass surface,
fourfold for the diamond side and fivefold for the grid side.
EXAMPLE IV
The procedures of example I are followed substantially as set forth
therein except that the square lands on one side measure 0.1 inch
.times. 0.1 inch and the square lands on the other side measure
0.025 inch .times. 0.025 inch (see FIGS. 9 and 12). There are 13.22
square lands per square inch in each plate. One embossing plate
with the large square lands has a surface coverage of 13.2 percent
and the other embossing plate with the small square lands has a
surface coverage of 0.83 percent.
These mating embossing plates are used to emboss an unbonded
woodpulp-filled card web sandwich comprising outer layers of KEYBAK
rearranged apertured nonwoven rayon card webs each weighing 125
grains per square yard and a centrally located woodpulp layer
weighing 350 grains per square yard, thus making a total weight of
600 grains per square yard.
Comparison of the wiping rate of such an embossed wiping fabric
with a nonwoven fabric which is identical in all respects thereto
except that it is not embossed reveals that the embossed wiping
fabric has a substantially improved wiping rate over the unembossed
wiping fabric for a water film on a glass surface. The wiping rate
of the embossed wiping fabric is also substantially improved over
an unembossed wiping cloth for wiping an oil film on a glass
surface.
EXAMPLE V
The procedures of example I are followed substantially as set forth
therein except that the square lands on one side measure 0.15 inch
.times. 0.15 inch and the square lands on the other side measure
0.025 inch .times. 0.025 inch (see FIG. 13). There are 13.22 square
lands per square inch in each plate. One embossing plate with the
large square lands a surface coverage of 29.7 percent and the other
embossing plate with the small square lands has a surface coverage
of 0.83 percent. These mating embossing plates are used to emboss
an unbonded woodpulp-filled card web sandwich comprising outer
layers of KEYBAK rearranged apertured nonwoven rayon card webs each
weighing 125 grains per square yard and a centrally located
woodpulp layer weighing 350 grains per square yard, thus making a
total weight of 600 grains per square yard.
Comparison of the wiping rate of such an embossed wiping fabric
with a nonwoven fabric which is identical in all respects thereto
except that it is not embossed reveals that the embossed wiping
fabric has a substantially improved wiping rate over the unembossed
wiping fabric for a water film on a glass surface. The wiping rate
of the embossed wiping fabric is also substantially improved over
an unembossed wiping cloth for wiping an oil film on a glass
surface.
EXAMPLE VI
The procedures of example I are followed substantially as set forth
therein except that the embossing land areas on one mating
embossing plate are rectangular and measure 0.2 inch .times. 0.15
inch and the embossing land areas on the other mating embossing
plate measure 0.025 inch .times. 0.025 inch. (See FIG. 14). There
are 13.22 embossing land areas per square inch in each plate. One
plate with the large rectangular lands has a surface coverage of
39.7 percent and the outer plate with the small square lands has a
surface coverage of 0.83 percent.
These mating embossing plates are used to emboss an unbonded
woodpulp-filled card web sandwich comprising outer layers of KEYBAK
rearranged apertured nonwoven rayon card webs each weighing 125
grains per square yard and a centrally located woodpulp layer
weighing 350 grains per square yard, thus making a total weight of
600 grains per square yard.
Comparison of the wiping rate of such an embossed wiping fabric
with a nonwoven fabric which is identical in all respects thereto
except that it is not embossed reveals that the embossed wiping
fabric has a substantially improved wiping rate over the unembossed
wiping fabric for a water film on a glass surface. The wiping rate
of the embossed wiping fabric is also substantially improved over
an unembossed wiping cloth for wiping an oil film on a glass
surface.
Although the present invention has been described with reference to
specific embodiments thereof, it is to be appreciated that such has
been done for illustrative purposes and that the present invention
is not to be considered limited thereby, except as noted in the
appended claims.
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