U.S. patent number 3,917,785 [Application Number 05/397,032] was granted by the patent office on 1975-11-04 for method for producing nonwoven fabric.
This patent grant is currently assigned to Johnson & Johnson. Invention is credited to Frank Kalwaites.
United States Patent |
3,917,785 |
Kalwaites |
November 4, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Method for producing nonwoven fabric
Abstract
A method of treating a layer of fibers to form a fibrous web
having various areas of fiber concentration and opacity. The fiber
layer is supported on an impermeable member and moving forces are
applied to the supported layer. The forces move the fibers into
areas of varying opacity and fiber concentration while maintaining
substantially uniform density throughout these areas.
Inventors: |
Kalwaites; Frank (Gladstone,
NJ) |
Assignee: |
Johnson & Johnson (New
Brunswick, NJ)
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Family
ID: |
27510209 |
Appl.
No.: |
05/397,032 |
Filed: |
September 13, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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295768 |
Oct 6, 1972 |
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110193 |
Jan 27, 1971 |
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Current U.S.
Class: |
264/108; 264/112;
264/128; 264/293; 264/546; 28/104; 264/121; 264/284; 264/557 |
Current CPC
Class: |
D04H
5/03 (20130101) |
Current International
Class: |
D04H
1/70 (20060101); D04H 001/50 (); D04H 001/70 ();
D04H 003/08 () |
Field of
Search: |
;264/108,109,121,128,88,293,284 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Goldstein; Melvin
Assistant Examiner: De Benedictis; Thomas
Parent Case Text
This is a division of application Ser. No. 295,768 filed Oct. 6,
1972, which in turn is a continuation in part of Ser. No. 110,193
filed Jan. 1, 1971 both abandoned.
Claims
I claim:
1. A method of treating a layer of fibers to form a web of fibers
having areas of varying opacity and varying fiber concentration
comprising: supporting a layer of fibers on an impermeable
patterned support member, applying a plurality of fiber moving
forces to one side of said supported layer, a substantial number of
forces acting in the plane of the layer and a substantial number of
forces acting at various angles to the plane of the layer, said
angle forces being applied and dissipated from the same side of the
layer whereby a pattern of areas of varying fiber concentration and
varying opacity is produced in the layer, said areas of varying
fiber concentration and varying opacity having substantially the
same fiber density throughout the fibrous web, said pattern
conforming to the pattern of said support member.
2. A method according to claim 1 wherein the fiber moving forces
are hydraulic forces.
3. A method according to claim 2 wherein the hydraulic forces are
drops of water uniformly distributed over the layer of fibers.
4. A method according to claim 2 wherein the hydraulic forces are
jets of water.
5. A method according to claim 1 wherein the forces acting at
various angles to the plane of the layer include forces acting
perpendicular to the plane of the layer.
6. A method according to claim 1 wherein the fiber moving forces
are sufficient to form holes in the layer of fibers.
7. A method according to claim 1 wherein the fiber moving forces
are arranged in a predetermined pattern over the layer of
fibers.
8. A method according to claim 1 wherein the web of fibers having
areas of varying opacity and varying fiber concentration is bonded
to produce a nonwoven fabric.
Description
BACKGROUND OF INVENTION
Patterned nonwoven fabrics have gained considerable importance over
the past years for many end uses. Nonwoven fabrics have been
developed with many differnt types of patterns; for example,
nonwoven fabrics which are bonded in patterns, nonwoven fabrics
which contain patterns of holes or areas of low fiber density, and
nonwoven fabrics which have an embossed pattern on them.
Patterned bonded fabrics generally comprise a layer of fibers to
which a binder is applied in a pattern of lines or dots or other
configurations. The binder is usually colored in order to give more
aesthetic qualities to the patterned bonded fabric.
Nonwoven fabrics containing patterns of areas of low fiber density
or holes usually comprise fiber segments which are formed as
bundles of fibers which define these holes. In some instances, the
fiber bundles may be coupled with areas of high fiber entanglement.
This technique is usually used to produce a strong fabric wherein
the fiber segments act together to produce stength and where
portions of fibers are highly entangled to also aid in giving
strength to the fabric. As a result of this fiber arrangement, the
pattern will be of holes or areas of low fiber density which
improve the aesthetic appeal of the fabric.
Embossed nonwoven fabrics are produced by standard embossing
techniques where areas are highly compressed or densified in a
pattern to produce a pleasing surface to the fabric and in some
instances, to control fluid absorption of the fabric and to improve
the aesthetic qualities of the fabric.
SUMMARY OF THE INVENTION
As used throughout this specification, "fiber concentration" means
the number of fibers in a plan area of a fabric or web; that is,
the number of fibers in a unit area of the web when the fibers
throughout the thickness of the web in that area are projected into
the unit area. Areas of varying fiber concentration will also have
varying opacity. The higher the fiber concentration in an area, the
higher the opacity or the more opaque the area. As used throughout
this specification, the term "fiber density" means the number of
fibers in a unit volume of the web.
I have discovered a new method for producing nonwoven fabrics
having varying patterns which greatly improves the aesthetic appeal
of the nonwoven fabrics. My new method is simple and can be run at
high production rates, making the process very economical.
In accordance with the present invention a layer of fibers is
treated to form a fibrous web having areas of varying opacity and
varying fiber concentration. The fibrous layer is supported on an
impermeable patterned support member and a plurality of fiber
moving forces are applied to the supported layer. A substantial
portion of the fiber moving forces act in the plane of the layer, a
substantial number of these forces act perpendicular to the layer,
and a substantial number of these forces act at varying angles to
the layer. The perpendicular and angle forces are applied and
dissipated from the same side of the layer of fibers to form a
pattern of areas of varying opacity and fiber concentration.
In certain embodiments of the present invention, there are few, if
any, perpendicular forces applied to the layer and all the fiber
moving forces act either in the plane of the layer or at an angle
to the plane of the layer. However, in all instances, the forces
acting at an angle to the plane of the layer are applied and
dissipated from the same side of the layer.
Fabrics produced utilizing my new method vary considerably. The
nonwoven fabrics produced will have areas of high opacity and areas
of lower opacity arranged in a predetermined pattern throughout the
fabric and all of these areas have substantially the same fiber
density throughout the fabric. The areas of high opacity and of
lower opacity will have different fiber concentrations. In some
instances, holes also may be produced in the fabric with the holes
also arranged in a predetermined pattern. In all instances, all of
the fiber areas throughout the fabric will have substantially the
same fiber density irregardless of their opacity.
The apparatus used in practicing my new method comprises an
impermeable member having a patterned surface. The fibrous layer to
be treated is placed on the impermeable patterned support member.
Spaced above the support member is means for directing fluid
against the fibrous layer while it is supported for applying fiber
moving forces to the supported layer. Though not absolutely
necessary, it is generally preferable that the fibrous layer be
covered by a permeable containing member to eliminate the
possibility of fiber wash away and to allow greater fiber moving
forces to be applied to the layer per unit time. The apparatus also
comprises means for removing the treated layer from the impermeable
support member. Certain embodiments of the apparatus also include
means for bonding the treated layer to produce a nonwoven
fabric.
By supporting a fibrous layer on an impermeable support member and
applying fiber moving forces to the layer while so supported, with
the forces being applied and dissipated from the same side of the
layer, these forces move the fibers into areas according to the
pattern of the support member. The fiber moving forces unexpectedly
form the web into areas of varying opacity rather than washing away
the fibers and completely disrupting the loose weak fibrous layer.
Many forces act in the plane of the web to shove fibers aside from
a particular area. Many of the forces also bounce back into the
direction from which new forces are being applied and unexpectedly,
do not disrupt the new forces being applied but instead, cooperate
with them to push the fibers into areas of varying opacity.
If the patterned support member has no resiliency, the forces
applied will unexpectedly move fiber segments in the layer from one
area to another area of the layer without changing the relative
configuration of fiber to adjacent fiber and hence form areas in
which the fiber segments are substantially as randomly laid as they
were in the original layer and merely form thicker areas in the
layer.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more fully understood from the description
which follows taken in conjunction with the accompanying drawings
in which are illustrated preferred designs of machines and modes of
operation embodying the invention along with varying types of
fabrics which may be produced in accordance with the present
invention. It is to be understood, however, that the invention is
not to be considered limited to the constructions or modes and
operations as disclosed except as determined by the scope of the
appended claims.
IN THE DRAWINGS
FIG. 1 is a diagrammatic showing in elevation of one type of
apparatus that may be employed in the present invention.
FIG. 2 is a fragmentary perspective view of one type of an
impermeable patterned support member which may be used in the
apparatus of FIG. 1.
FIG. 3 is an enlarged fragmentary diagrammatic view of means for
applying fiber moving forces to a layer of fibers.
FIG. 4 is an enlarged fragmentary diagrammatic view of another
means for applying a plurality of fiber moving forces to a layer of
fibers.
FIG. 5 is an enlarged fragmentary diagrammatic plan view of a means
for containing a layer of fibers on the impermeable patterned
support member.
FIG. 6 is a cross-sectional view taken along line 6--6 of FIG.
5.
FIG. 7 is a cross-sectional view taken along line 7--7 of FIGS. 5
and 6.
FIG. 8 is a schematic plan view of a nonwoven fabric made in
accordance with the present invention.
FIG. 9 is a cross-sectional view taken along line 9--9 of FIG.
8.
FIG. 10 is a plan view of another embodiment of a nonwoven fabric
in accordance with the present invention.
FIG. 11 is a cross-sectional view taken along line 11--11 of FIG.
10.
FIG. 12 is a photomicrograph of a nonwoven fabric made in
accordance with the present invention, shown at an original
enlargement of 5 times.
FIG. 13 is a photomicrograph of another nonwoven fabric made in
accordance with the present invention shown at an original
enlargement of 5 times.
FIG. 14 is a photomicrograph of another nonwoven fabric made in
accordance with the present invention shown at an original
enlargement of 5 times.
FIG. 15 is a photomicrograph of another nonwoven fabric made in
accordance with the present invention shown at an original
enlargement of 5 times.
FIG. 16 is a photograph of the nonwoven fabric shown in FIG.
12.
FIG. 17 is a photograph of the nonwoven fabric shown in FIG.
14.
FIG. 18 is a photograph of a nonwoven fabric made in accordance
with the present invention and similar to the fabric shown in FIG.
15.
Referring to FIG. 1 of the drawings, there is shown one form of
apparatus which may be used in accordance with the present
invention. The apparatus comprises a rotatable roll 30. The surface
of the rotatable roll is patterned and is impermeable and is used
to support the layer of fibers 31 during treatment. A foraminous
containing member 32 which is an endless belt, covers a substantial
portion of the periphery of the rotatable roll. The containing belt
passes about the rotatable roll and separates from the roll at the
guide roll 33 which rotates on a shaft 34. The belt passes over a
second guide roll 35 and then downwardly around the guide roll 36
rotating on the shaft 37 and then rearwardly over vertically
adjustable tensioning and tracking guide roll 38 and around guide
roll 39 on shaft 40. The belt passes upwardly and around guide
rolls 41 and 42, rotating on shafts 43 and 44 to be returned about
the periphery of the roll 30. The roll and containing belt are
moving in the same direction and at the same peripheral linear
speed. The rotatable roll and the containing belt provide a
treating zone between them through which a layer of fibrous
materials may move to be treated under the influence of fiber
moving forces.
Tension on the containing belt is controlled and adjusted by a
tensioning and tracking guide roll. The guide rolls are positioned
in slidable brackets which are adjustable to assist in the
maintenance of proper tension of the belt. The tension required
will depend upon the weight of the fibrous layer being treated and
the amount of fiber movement desired.
The fibrous material to be treated is fed between containing belt
and rotatable roll at point "A", passes through a fiber moving zone
where the fiber moving forces are applied to it and is removed in
its new treated form between the rotatable roll and the containing
belt at point "B".
As the fibrous layer passes through the treating zone, a liquid
such as water is directed against the outer surface of the
containing belt by nozzles 45 mounted outside the rotatable roll. A
plurality of these nozzles are mounted outside the rotatable roll
and generally direct water at an angle to the surface of the
rotatable roll and containing belt. The water passes through the
containing belt and hits the layer of fibers and the impermeable
rotatable roll and applies forces within the layer of fibers as
well as at varying angles to the layer of fibers. All of the forces
are applied and dissipated from the same side; that is, the liquid
acts in the layer of fibers and bounces back away from the layer of
fibers in the same general direction from which the forces were
applied. The liquid is caught in a suitable catch basin 46 and
recycled for further use.
A vacuum assist box 47 is located outside the containing belt and
aids in dewatering the fibrous layer after it passes through the
treating zone. The treated layer 48 is removed from the containing
belt and passes over a roller 49 and through a pair of bonding
rolls 50 and 51. The bottom roll 51 is partially immersed in a pan
52 containing a suitable binder material. The roll 51 is engraved
in a pattern and picks up binder in this pattern and applies it to
the layer of fibers. The layer of fibers with the binder thereon is
dryed over suitably heated drums 54 and wound up on a standard
wind-up mechanism 55.
In FIG. 2, there is shown an enlarged fragmentary view in
perspective of one type of impermeable support member 60 which may
be used in accordance with the present invention. The surface 61 of
the roll is solid and has a plurality of depressions 62 arranged
over the surface in a pattern.
The depressions or raised areas, as the case may be, in the
impermeable support member may have varying configurations, that
is, they may be circular, oval, rectangular, square, or other
shapes. These areas may be arranged either diagonally or in an
aligned relationship over the surface of the roll.
Referring to FIGS. 3 and 4, there are shown enlarged fragmentary
views of types of fiber moving zones. In FIG. 3, there is shown an
impermeable support member comprising a solid roll 70 having a
pattern of square depressions 71 arranged over the surface. The
fibrous layer 72 to be treated is placed on the surface of the
roll. A liquid 73 such as water is directed against the layer while
it is supported, by a plurality of spray nozzles 74. The spray from
the nozzles overlaps so that the entire layer is treated. The water
enters the fibrous layer in an angular fashion so that forces act
within the fibrous layer at an angle or in the plane of the layer
and bounce back out of the layer at an angle.
In FIG. 4, again there is shown an impermeable support member 80
having an absorbent surface 81 such as a foam or similar material.
The layer of fibers 82 to be treated is placed on the absorbent
surface and a liquid 83 such as water is directed at the layer of
fibers, while so supported, by a plurality of jets 84. The surface
81 and the layer of fibers 82 move in the direction of the arrow as
shown and the water hits the layer and applies forces to the layer
of fibers to form areas of varying fiber concentrations and the
water bounces back out of the layer of fibers.
Whether or not a containing belt is required during the fiber
treatment will depend upon many variables, for example, the weight
of the fibrous web being treated, the speed of operation, the force
or pressure of the liquid being applied during the treatment, the
manner in which the liquid is applied, that is, the varying angular
directions and whether a fine spray or a stream of water is used.
Generally, fiber movement can be accomplished at a greater rate of
speed when a containing belt is used. The containing belt is merely
to hold the fibers in the treating zone and prevent them from being
bounced out of the treating zone. Virtually, any permeable open
member may be used such as an open woven cloth or nylon belt.
FIG. 5 is an enlarged fragmentary diagrammatic plan view of one
type of containing belt which may be used in the apparatus of FIG.
1. Foraminous portions 90 of the containing belt for use in this
invention are formed of coarse woven screen. In the embodiment
shown, wires 91 running vertically in FIG. 5 are straight and wire
92 running horizontally in that Figure weave alternately over and
under wires 91. Protuberances 93 are present throughout foraminous
portions 90 as the topmost part of each "knee" of a given strand 92
of the screen that is formed as the strand weaves over and under
the strands 91 that lie perpendicular to it.
As a given strand 92 slants downward to pass under a strand 91
perpendicular to it, it crosses two other strands 92 disposed on
either side of it, as those strands slant upward to pass over the
same perpendicular strand that the given strand will pass under.
Each eries of such "crossing points" 94 forms a trough, such as
trough 95 formed by crossing points 94 in FIGS. 5 and 6, that lies
between adjacent protuberances 93. The effective shape of troughs
95, as can be best seen in FIG. 6 (which shows a cross section of
element 90 of which a plan view is given in FIG. 5) is
substantially an inverted triangle.
A series of slightly deeper troughs 96 is formed between adjacent
protuberances 93. As best seen in FIG. 7, the bottom of each trough
96 is formed by portions of straight strands 91, with successive
protuberances 93 on each side of the trough forming the tops of
troughs. As seen in FIG. 7, the effective shape of troughs 96, may
be characterized as a shallow "U" shape.
Use in the method or apparatus of this invention of a containing
belt such as shown in FIGS. 5 through 7, produces a pattern of
untreated areas in the fibrous web. These untreated areas
correspond to the high points of the containing belt where this
belt is held against the impermeable support member and locks that
portion of the fibers to the impermeable support member so that it
cannot be treated. This technique forms some very interesting
patterns in the final web of fibers.
Portions of the streams of treating fluid pass through the
containing belt and the layer of fibers and are directed in the
layer of fibers and also directed back out of the layer of fibers
at varying angles to the layer of fibers. The liquid forces are
dissipated from the same side of the layer of fibers to which they
were directed. These varying forces move the fibers in accordance
with the pattern in the impermeable support member and/or the
pattern in the restraining belt to form areas of varying fiber
concentration. In certain embodiments, the forces may even form
openings or holes in the layer of fibers and in other embodiments
if the containing belts as described in conjunction with FIGS. 5-7
are used, will form patterns in the fibrous layer in which the
fibers are untreated and remain in their original configuration and
concentration.
The treated web produced by the practice of this invention, may be
further treated with an adhesive, dye or other impregnating,
printing or coating material in a conventional manner. For example,
to strengthen a fibrous web, any suitable adhesive bonding
materials or binders may be included in an aqueous or non-aqueous
medium employed as the treating fluid. Or, an adhesive binder may,
if desired, be printed or sprayed on the treated web to provide the
necessary fabric strength. Thermoplastic binders may, if desired,
be applied to the treated web in powder form or fiber form during
or after treatment and then fused to bond the other fibers.
The optimum binder contents for a given fabric according to this
invention depends upon a number of factors, including the nature of
the binder material, size and shape of the binder members, and
their arrangement in the fabric, the nature and length of the
fibers' total fiber weight, and the like. In some instances because
of the strength of the fibers used or the type of interentanglement
in the treated web or fabric, no binder at all need be employed to
provide a usable fabric.
The starting material used in the method or apparatus of this
invention may be any of the standard fibrous webs such as oriented
card webs, isowebs, air-laid webs, or webs formed by liquid
deposition. The webs may be formed in a single layer or by
laminating a plurality of the webs together. The fibers in the web
may be arranged in a random manner or may be more or less oriented
as in a card web. The individual fibers may be relatively straight
or slightly bent. The fibers intersect at various angles to one
another such that generally speaking, the adjacent fibers come into
contact only at the points where they cross. The fibers are capable
of movement under forces applied by fluid, such as water, air,
etc.
To produce a fabric having the characteristic hand and drape of a
textile fabric, the layer of starting material used in the method
or apparatus of this invention may comprise natural fibers such as
cotton, flax, etc.; mineral fibers, such as glass; artificial
fibers, such as viscose rayon, cellulose acetate, etc.; or
synthetic fibers such as the polyamides, the polyesters, and
acrylics, and polyolefins, etc., alone or in combination with one
another.
The fibers used are those commonly considered textile fibers which
generally are from about one-fourth inch to about 21/2 inches.
Satisfactory products may be produced in accordance with the
present invention from starting webs weighing between 80 grains per
square yard to 2,000 grains per square yard or higher.
The treating fluid for use in this invention is preferably water or
a similar liquid but it may be other fluids such as gas, etc.
The new nonwoven fabrics produced by the methods of the present
invention may have a very wide variety of patterns of holes, areas
of varying fiber concentration or both. Also, the holes and areas
of varying fiber concentration may have varying configurations, as
previously mentioned.
Referring to the drawings in FIGS. 8 and 9, there is shown a
nonwoven fabric 100 of the present invention. The fabric comprises
circular areas 101 running the length and width of the fabric. In
the center of each circular area is a cluster 102 of fiber
portions. The circular areas are connected by fiber areas 103
extending continuously throughout the fabric. The fiber areas 103
have a cetain fiber concentration which is substantially uniform
throughout the fabric and as is more clearly shown in FIG. 9, the
area 103 is the thickest portion of the fabric. The circular areas
101 have a lower fiber concentration and are thinner than areas
103. The circular areas are less opaque than the remainder of the
fabric.
In FIGS. 10 and 11, there is shown another embodiment of the
nonwoven fabric of the present invention. The nonwoven fabric 105
comprises square areas 106 of low fiber concentration and low
opacity. The fibers in the square areas are arranged in
helter-skelter, intersecting relationship. The fabric has a
plurality of longitudinal extending lines 107 and transversely
extending lines 108 which intersect each other. The fibers in these
lines are also in helter-skelter, intersecting relationship. The
lines have a considerably higher fiber concentration, than the
square areas and as is seen in FIG. 11, are thicker than the square
areas.
A similar fabric to the fabric described in conjunction with FIG. 8
is shown in the photomicrograph FIG. 12. The fabric 110 comprises
circular areas 111 of low fiber concentration. The circular areas
are surrounded by and connected by areas 112 of higher fiber
concentration. The fibers themselves in all areas of the fabric are
in random, helter-skelter intersecting relationship. This same
fabric is shown in the photograph shown in FIG. 16.
In the photomicrograph shown in FIG. 13, the fabric 115 comprises
circular areas 116 of high fiber concentration. The circular areas
are in staggered rows and are connected diagonally throughout the
fabric by fiber bands 117 of medium fiber concentration. The
remaining areas 118 of the fabric have a very low fiber
concentration and in some instances are partial holes or openings
in the fabric.
Referring to FIG. 15, there is shown another embodiment of the new
nonwoven fabric 120 of the present invention. The fabric comprises
square areas 121 arranged longitudinally and transversely of the
fabric. The areas 121 are discontinuous and have a higher fiber
concentration than the remainder of the fabric. These areas 121 are
also more opaque than the longitudinal and transverse lines 122
that connect the areas.
In FIG. 18, there is shown a photograph of a fabric 125 similar to
that shown in FIG. 15 except the pattern of high fiber
concentration areas and low fiber concentration areas is different
and considerably more complex. The discontinuous areas of random
configuration 126 have a low fiber concentration and even some
holes 127 are present. The lines 128 also have a low fiber
concentration. The remaining area 129 of the fabric has a high
fiber concentration which is substantially uniform throughout the
fabric.
The following are illustrative Examples of the use of the method
and apparatus of this invention to produce webs having patterns of
varying fiber concentrations.
EXAMPLE I
In apparatus as illustrated in FIG. 1, a web of loosely-assembled
fibers such as may be obtained by carding, is fed between
containing belt 32 and impermeable support roll 30. The web weighs
about 400 grains per square yard and its fiber orientation ratio is
approximately 7:1 in the direction of travel. The web contains 40
percent viscose rayon fibers approximately three-eighth inch long
of the 11/2 denier, and 60 percent wood pulp. The impermeable
support roll used 7:1 this Example has about 100 round nubs or
raised areas per square inch, each approximately 0.035 inches in
diameter and one-sixteenth inch high. The areas are arranged in
rows aligned across the roll and about the periphery of the roll.
The containing belt used comprises a woven nylon screen of
approximately 90 .times. 90 construction or substantially 8,100
openings per square inch. The belt has approximately 60 percent
open area.
Water is projected from nozzles through the containing belt and
against the support member. The water is directed at pressures of
about 80 to 100 psi. The nozzles used are conventional solid cone
nozzles and the water is directed at the rate of 1.3 gallons per
minute in the treating zone. The treated fabric then passes to the
take-off zone and leaves the apparatus. With the conditions
indicated, good fiber movement is obtained and an excellent
material such as shown in the schematic drawings in FIGS. 8 and 9,
and the photomicrograph of FIG. 12 and the photograph of FIG. 16 is
obtained.
The fabric 110 of FIG. 12 contains a continuous pattern of a high
fiber concentration 112 extending substantially uniformly
throughout the fabric. Disposed on this pattern are circular areas
111 of low fiber concentration. These circular areas are disposed
longitudinally and transversely of the fabric. In substantially the
center of each circular areas there is an area or cluster 113 of
yet another fiber concentration which is basically the originally
untreated portion of the layer of fibers.
In FIG. 16, there is a photograph of the fabric which shows the
overall aesthetic appeal formed in the fabric by the patterns of
varying fiber concentrations.
EXAMPLE II
FIGS. 10 and 11 are a schematic plan and a cross-sectional view of
another nonwoven fabric made in accordance with the present
invention with the use of apparatus similar to that described in
Example I with the exception that the impermeable support member
used contains a pattern of discontinuous raised square areas. There
are approximately 100 square areas per square inch and these areas
run longitudinally and transversely of the support member. The
square areas are about 0.075 inch by 0.075 inch.
The containing belt used, rather than having high protuberances
described in conjunction with Example I, has a relatively smooth
surface. The resultant fabric comprises a pattern of square areas
corresponding to the pattern of square areas in the support member
which have a low fiber concentration with a continuous pattern of
transversely and longitudinally running lines having areas of high
fiber concentration. A photomicrograph of this fabric is shown in
FIG. 15 and an actual photograph showing the aesthetic appeal of
these types of fabric is shown in FIG. 18.
EXAMPLE III
Using the apparatus as illustrated in FIG. 1, a web of loosely
assembled fibers such as may be obtained by carding, is fed between
the impermeable support means 30 and a containing belt 32. The web
weight is about 400 grains per square yard and its fiber
orientation ratio is approximately 7:1 in the direction of travel.
The web contains viscose rayon fibers approximately 1 9/16 inches
long of 11/2 denier.
The impermeable support member has about 25 substantially round
depressions per square inch. Each depression is approximately
one-eighth inch in diameter and one-sixteenth inch deep and these
depressions are arranged in a diamond pattern over the support
member. The containing belt used is that described in conjunction
with Example I and is shown in FIGS. 5 and 7. Water is directed
against the containing belt as described in conjunction with
Example I. With the conditions indicated, good fiber treatment is
obtained and an excellent nonwoven fabric such as shown in the
photomicrograph of FIG. 13, is produced. The fabric of FIG. 13,
contains a discontinuous pattern of circular areas 116 of high
fiber concentration arranged in accordance with the pattern of the
depressions in the impermeable support member. These circular areas
are connected in a diagonal direction of the fabric by areas of
medium fiber concentration 117 and form an opening 118 or hole in
the fabric. The center of the opening has a fiber area
corresponding to the high points of the containing belt. The fiber
configuration in these areas is substantially the same as in the
original web.
EXAMPLE IV
The fibrous starting material and the apparatus employed in this
Example are the same as those employed in Example III with the
exception that the support member is a smooth surfaced rotatable
roll which is impermeable but has a surface covered with
polyurethane foam material approximately one-eighth inch thick. The
resulting fabric 134 is seen in FIGS. 14 and 17 and comprises a
random pattern of areas 135 of varying fiber concentration with a
random pattern of holes 136 extending throughout the fabric.
The above detailed description has been given for clearness of
understanding only. No unnecessary limitations should be understood
therefrom as modifications will be obvious to those skilled in the
art.
* * * * *