Note: Descriptions are shown in the official language in which they were submitted.
This invention relates to a novel melange-colored sheet
having at leas-t on one surface a layer o super-entangled ultrafine
fibers and/or ul-trafine fiber bundles comprisLng at least -two -types
of ultrafine fiber, both of which are branched from the ultrafine
fiber bundles and/or multi-core fibers of -the inner portion. The
bundles and/or multi-core fibers are different in color so that the
surface presents a melange color. This invention also relates -to a
me-thod of producing said novel melange-colored sheetO
This invention is related to and is an improvement upon the
invention disclosed in applicant's Canadian Application filed con-
currently herewith.
A typical example of conventional grained artificial
leather i5 obtained by forming layers of elastic polymer such as
polyurethane on fiber substrate and providing a pattern to the
surface of the polymer layer by embossing or forming layers of
grain patterned elastic polymer on the flber substrate by transfer
coating. Japanese patent application publication ~o. 27636/81 des-
cribes an artificial leather which comprises a very thin poly-
g~2~
urethane surface and an ultrafine fiber substrate, but fails toteach any melange-colored and super-entangled ultrafine fiber sur-
face. Laid-open Japanese. patent applica-tion publica-tions ~los.
33221/78 and 106668/79 describe melange-colored art.iicial suede
comprising ultrafine fiber naps extending from. differently colored
ultrafi.ne fiber bundles. However, these re:Eerences are silent
about super-entangled surfaces of differently colored ultra.Eine
fibers. Laid-open Japanese patent application ~o. 66188/82 des-
cribes a melange type shee-t composed of two types of fibers, but
the surface is buffed before dyeing to obtain artificial suede.
Moreover it fails to teach ultrafine fiber bundles constituting the
inner portion of -the sheet.
In diversifying such techniques for making grained artifi-
cial leather, attempts have been made to obtain melange-colored
artificial leathers corresponding to natural leather dyed with an
aniline type dyestuff which shows varying shades, lighter and
darker in various parts.
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The aniline (synthetic dye) finish shows ~f--f-ectiv~
varyiny shades o surface color in the natural leather.
However, the melange-colored grained sheet of the present
invention includes not only such effect but also presen-ts a
complex grain pattern in two or more kinds of color such as
in melange dyeing, which is hard to obtain in natural
leather.
Processes have been used for providing different
colors in conventional artificial leathers, as mentioned
above, such as forming a layer of a mixture of elastic
polymers containing different pigments, or coating unevenly
with a gravure roll or spraying palnts of different colors,
However, these have both the disadvantages of falling-off of
the provided different color layer due to abxasion or
deterioration of the resin or vehicle, and tne surface has a
rubber-like or plastic feel due to the presence of the
elastic polymer/ coupled with a plastic appearance, all
being much inferior to dignified aniline-finished natural
leather.
Furthermore, even aniline-finished natural leather
has the disadvantages of easily becoming bruised and easily
stained because it is colored by splashing, which causes
short liEe without constant maintenance. It is also unable
to provide further complexity in color or a high-grade
--3--
feeling with a sober color.
The present invention overcomes the disadvanta(Jes of con-
ventional artificial leathers, such as fallinq-oE~ of ~he melange-
colored layer and the rubber-like or plastic ~Eeeling, as well as
obtaining a complicated melange-colored effect, not obtainable even
Erom natural leather. It furthe~ has the advantage of easy care.
The present invention is directed to providing a digni-
fied novel sheet having a melange-colored surface with a high grade
feel and wi-thout rubber-like or plastic feel, and -to providing a
method for the preparation thereof. The present invention also
attem~ts to provide a melange-colored grained sheet having a com-
plicated and delicate color mixing effect which cannot be obtained
in natural leather. A method for producing the sheet is also pro-
vided.
According to the present invention, there is provided a
novel melange-colored sheet having a body portion comprising fibers
in a form selected from ultrafine fiber bundles, multi-core fibers
and a mixture of ultrafine fiber bundles and multi-core fibers and
a super-entangled surface portion on at least one of the surfaces
of said body portion, said surface portion having at least one of
the group consisting of super-entangled ultrafine fibers and fine
bundles of ultrafine fibers, the surface portion comprising at
least two types of ultrafine fibers, both of which are branched
from said body portion, said types of ultrafine fibers being
different in color so that said super-entangled surface portion
visually presents at least two colors.
_ ~
Thus, the novel melange-colored sheet has an inner
portion and on at least one surface of the inner portion a por-tion
comprising super entangled ultrafine fibers and/or ultrafine fine
fiber bundles comprising at least two types of ultrafine fibers,
both of which are branched from -the fiber bund:Les and/or multi-core
fibers of
~ 4a --
~2~ 3
1034-83
I
the inner portion, wherein said bundles and/or multi-core
fibers are different in color so that -the surface presents
at leas-t two colors.
According to this invention, a method is provided
for producing a novel melange-colored sheet having on at
least one of the surfaces of the inner portion, a portion
comprising super-entangled ultrafine fibers and/or ultrafine
fiber bundles comprising at least two types of ultrafine
fibers, which ultrafine fibers are branched from ultrafine
fiber bundles and/or multi-core fibers of the inner portion,
wherein said ultrafine fiber bundles and/or -fibers are
different in color so that said layer presents at least two
colors, said method comprising the steps of:
(1) forming a fiber entangled sheet comprising at
least two kinds of ultrafine fiber formable fiber
bundles having different dyeing properties,
(?) forming a super-entangled layer of ultrafine
fibers and/or fine bundles of ultrafine fibers on at
least one surface of said sheet by applying jet
streams of high speed fluid, and
(3) dyeing with different types of dyestuff.
- Although specific examples of the invention
have been selected for illus-tration in the drawings, they
are not intended to limit the scope of the invention.
--5--
~Z9L~3
Similarly, while specific -texms will be used in the following
description of the embodiments selected for illustration, -these
terms are not intended to limit the scope of the invention, which
is defined in the appended claims.
Fig. 1 is a schematic view of entangled cons-tituen-t
ultrafine fibers of the surface side of a sheet of the present
invention.
Figs. 2(a) to 2(o) are schematic sectional views showing
-typical examples of fibers which may be used to form the ultrafine
fibers employed in the present inven~ion.
Figs. 3(a) and 3(b) show, in cross section, fibers which
may be used alone (and not necessarily in combination with other
fibers) in accordance with this invention.
Fig. 4 is a schematic, idealized illustration, in
section, of a portion of a fibrillated sheet in accordance with
this invention, shGwing a super-entangled surface portion which,
after treatment, becomes a grained surface portion of the finished
sheet.
Figs. 5 and 6 are schematic illustrations showing sheet
structures at various stages in typical processes in accordance
with selected embodiments of this invention.
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The term "ultrafine fiber bundle" as used herein
denotes a fiber bundle in which a plurality of fibers in
staple or filament form are arranged substantially in
parallel with one another. The fibers may all be of the
same type or a combination of fiber types.
The term "grained sheet" is not intended to be
limited to leather alone, but is directed broadly to sheets
composed of fibrous materials with surface fibers in fixed
position~ in any arrangement to provide a grain-like
structure. It includes synthetic materials composed of
fibers, fiber bundles or ultrafine fibers or bundles and
resin in a wide variety of structural arrangements,
including suede leathers and suede-like fabrics, including
leather-like products having branched bundles of fibers or
ultrafine fibers.
~ s used herein the term "grain" is intended to be
directed broadly to a surface portion of the sheet, and
refers particularly to ultrafine fibers or ultrafine fiber
bundles, or mi~tures of the two, branching from ultrafine
fiber bundles of a sub-surface portion of the sheet, and a
resin in the gap portions of the ultrafine fiber structure.
The ultrafine fibers and ultrafine fiber bundles of the
grain, in accordance with this invention, are
superentangled, which is an importan-t feature oE the
~ _7_
.,
~2~
1034-83
invention as will be explained in further detail
hereinafter.
In some cases fibrous materials rnay be made having
superentangled ultrafine fiber surfaces without any resin
material on -the surface thereof. Such sur-faces are intended
to be included within the scope of this invention but are
not referred to as "grained" surfaces.
~ aving quite a different concept from the
conventional aniline-style artificial leather, the
melange-colored sheet of the present invention shows no
vinyl or rubber feel due to the presence of any elastic
polymer layer and is less susceptible to peeling-off from
abrasion and deterioration, yielding quite an innovative
different colored aniline effect. The melange-colored
surface consists of a layer in which ultrafine fibers of not
more than 0.5 denier, preferably extremely ultrafine fibers
of not more than 0.2 denier, are super-entangled preferably
as fibrils branched ou-t of the fiber bundles. It presents
at least two different colors or color shades. The
melange-colored aniline effect of the surface attributed to
the presence of the ultrafine fibers themselves is based on
a concept quite different from the aniline finishing of
natural leather. It has been impossible before the advent
of the present invention -to obtain the novel complex
_~_
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melange-colored aniline effec-t; it is not obtainable from
natural leather. The present invention is further
advantageous because it possesses an ease of care which i5
characteristic of artificial leather. The above-mentioned
melange-colored e:Efect is a unique fea-ture of the grained
surface layer of the sheet of this invention, and is
essentially different from the mel.ange effect of fluffy
suede-type artificial leather.
Various ultrafine fibers may be used in the
present invention. There may be mentioned those which are.
produced by various methods, such as super-drawing, jet
spinning using a gas stream, and so forth. In accordance
with these methods, however, spinning becomes unstable and
difficult if the fiber size becomes too fine. For these
reasons, it is preferred to employ particular types of
fibers which are formable into ultrafine fibers and to
modify them into ultrafine fibers at a suitable stage of the
production process. Examples of such ultrafine formable
fibers include multi-core fibers having chrysanthemum-like
cross-sections in which one component is radially interposed
between other components, multi-layered bicomponent type
fibers, multi-layered bicomponent type fibers having a
doughnut-like cross-section, mixed spun Eibers obtained by
co-e~truding at least two components and spinning (in some
_g_
.",~
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cases a small amount of a second component, i.e.
polyethylene glycol is very effective to separa-te a large
amount of core component, i.e. polyethylene-terephthalate),
islands-in-a-sea type multi-core fibers in which a plurality
of ultrafine cores that are lonyitudinally continuous are
bound together by other components, specific
islands-in-a-sea fibers in which a plurality of
extra-ultrafine cores are bonded together by other
components to form a fiber, and so forth. Two or more of
these fibers may be mixed.
It is preferable to use multi-core fibers in which
a plurality of cores are interposed with other binding
components, because it becomes easy to provide ultrafine
fibers by applying physical or chemical ac-tion or by
removing only the binding components.
It will be appreciated that the term "cores" as
used herein is broadly applicable to ultrafine fibers or
precursors thereof, in a wide variety of arrangements.
"core" does not need to be cen-trally located, or surrounded
by other materials, but may be any one of a plurality of
elements co-extruded into any of a wide variety of geometric
shapes. Such "cores" may be embedded in a sea component, as
shown in Figs. 2(a) and 2(h) for example, or may be combined
in a side-by-side arrangement as shown in Fig. 2(m) or 2(n),
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]03~-83
for example, or in a wide variety of other configurations.
Figs. 2(a) to 2(o) show examples of selected
multi-core fibers which may be used to obtain the ultrafine
fibers. In Figs. 2(a) to 2(o) r reference numbers 1 and 1'
represent ultrafine cores and 2 and 2' represent binding
components. The cores may be composite cores consisting of
different polymeric materials. The cores may be crimpable
cores, modified cross-section cores, hollow cores,
multi-hollow cores and the like. Further, ultrafine cores
of different kinds may be mixed.
In Fig. 3(a) the number 1 designates a core of a
particular kind ~polyethylene terephthalate, for example).
The number 2 designates a different core which has different
dye-accepting properties ~nylon 6-6, for example). The
number 3 designates a sea component which may, for example,
be polystyrene. It will accordingly be apparent that the
melange-colored effect of this invention may be obtained
from this multi-core fiber alone, because of the difference
of dye reception of cores 1 and 2.
Fig. 3(b) shows a doughnut-shaped cross-section
having a hollow portion 4 and a ring portion composed of
wedge-shaped portions of two different polymers 1 and 2.
For eY~ample, portions 1 may be polyethylene terephthala-te
and portions 2 may be nylon 6-6. It will be apparent that,
--11--
after partial or com~le-te mechanical or other separation, ultrafine
fibers and Eiber bundles having difEerent dye recep-tive proper-ties
are provided.
The shapes of -the cross sections of ultrafine formable
fibers used in th0 present invention also include wide varieties of
sec-tions such as round-shaped, fan-shaped triangle, fan-shaped
frus-tum, cross-shaped, T-shaped triangle, roundish triangle-shaped,
various multi-lobal shapes, hollow, hollow deformed and ellip-tical
sections, for example.
In order to ob-tain a super-entangled leather, the size of
the ultrafine fiber should preferably not be greater than about 0.5
denier, more preferably not greater than about 0.2 denier. A
greater size resul-ts in inferior smoothness of the surface, making
it virtually impossible to accomplish the object of the present in~
vention. Finer fibers may be used, even the fines-t. Th~ order of
0.00001 denier is usually a practical limitation in preparation,
without limiting the scope of the invention thereto.
As a matter of course, ordinary denier fiber or foreign
substances such as additives may be permi-tted to coexist if the ex-
tent is limited in a manner not to spoil the effects of the presentinvention.
This means, for example, that a small amount of
~ 12 -
~.z~ ffl~
1034-83
thick fiber not smaller than 0.9 denier may be included with
a majority of ultrafine fibers. It also me!ans that when an
ultrafine fiber is made by splittiny a mul-ti-core fiber, -the
other componen-t interposed among -the u}trafine cores might
remain as a relatively thick fiber or the ultrafine iber
itself might remain thick without being made ultrafine. 1,
Even in such a case the present invention can be fully
accomplished if the amount of the remaining thick fiber
remains in the minority. In any case, alterations not
interfering with the functional effect of the present
invention as a whole are included in the scope of the
present invention.
In the fibrous sheet of the present invention a
nonwoven fabric such as needle punched felt is preferred.
However, a composite sheet in which woven or knitted fabric
is present internally or on the bac~ surface may be adapted.
It is essential that the above-mentioned fibrous sheet has a
surface portion comprising ultrafine fibers and/or bundles
of ultrafine fibers, that both of those are branched from
ultrafine fiber bundles or multi-core fibers of the inner
portion and that said ultrafine fiber bundles and/or
multi-core fibers are different in color or color shade.
If the surface structure is locally impregnated
with a res:in to fix the superen-tangled ultrafine fibers ln
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1034-83
place, a grained structure is obtained; embossing is
advantageously used on such a grained surface.
If the surface layer has a structure according to
the present invention, it may be combined with other fibrous
sheets, and various combinations of layers may be provided.
It is required that the fiber structure in the
sheet of the present invention be such that the ultrafine
fibers and the fine bundles of ultrafine fibers are
super-entangled with one another. In other words, it is
necessary that the entanglement density of the fibers be
high. One of the methods of measuring the entanglement
density of the fibers is to measure the distances between
represen-tative fiber entanglement points. A short average
distance between points of entanglement evidences a high
density of entanglement.
The distance between the fiber entanglement points
is desirably the mean of all entanglement distances. It is
not necessary, of course, to measure all such distances
since a representative sample is enough. The mean
entanglement distance is measured in the following manner.
Fig. 1 is an enlarged schematic view of the constituent
fibers in the surface of a typical sample when viewed from
the surface side. Assuming that the constituent fibers are
fl~ f2, f3, ...~., the point at which two arbitrarily
4~
1034--83
selected fibers fl and f2 are entangled with each other is
al, and the point at which -the upper fiber f2 is entangled
with another fiber with the fiber f2 being the lower fiber
is a2 (the entanglement point between f2 and f3).
Similarly, -the entanglement points a3, a~, a5...... are
located and positioned. The linear distances ala2,
a a a a4~ a4a5~ a5a6~ a6a7, a7a3, a3a8, a8 ~, 7 3 9 6
.... are measured along the surface of the sample. These
are the distances between representative fiber entangling
points which appear in Fig. 1. These distances are then
added and divided by the number of measurements to give a
mean.
In the present invention, the fibers of the
surface must have an entanglement density of not greater
than about 200 microns as measured by this method. This is
what is meant where, in the specification and in the claims,
we refer to the fibers as being "super-entangled". In fiber
structures where the entanglement density is greater than
about 200 microns, such as those fiber structures in which
the entanglement of the fibers is effected only by needle
punching, in which ultrafine fibers or bundles are merely
arranged along the surface or, in which thickly raised
ultrafine fibers or bundles are laid down on the surface of
a substrate to form a grain, li-ttle or no entan~lement of
~15-
1034-83
the fibers occurs.
When friction, crumpling and shearing stress are
repeatedly applied -to such fahrics the surface is likely to
fluff in an unsightly manner or to develop cracks. To
eliminate these problems, the mean distance between the
fiber entangling points must be not greater than about 200
microns. More favorable results are obtainable when the
mean distance is no-t greater than about 100 microns.
The fibrous grained sheet of the present invention
may include various conventional kinds of viscoelastic
polymers such as polyurethane and acryl resins and silicone
rubber, for example. Such additives as pigments, dyestuffs
or weather resistant agents may be added to the
above-mentioned resins and a more compllcated melange-color
effect is obtainable by selecting appropriate pigments or
dyestuffs.
A feature of the artificial leather according to
the present invention is the exhibition of different colors
by the ultrafine fibers constituting the surface. The
foregoing feature is attainable by using various dyeing
methods. A most effective method consists of making the
ultrafine fibers constituting the surface from at least two
kinds of ultrafine fibers which differ in dyeing properties
from each other, and dyeing each fiber with different types
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of dyestuff.
According to differences in dye:ing proper-ties, the
fibers may be classified as disperse dye dyeable type
fihers, acid dye dyeable type fibers, basic dye dyeable type
fibers or direc-t or reactive dye dyeable fibers, for
example. From among these a combination of a-t least two
different types of fiber bundles may be selected.
The disperse dye dyeable fibers include
polyethylene-terephthalate, polyoxyethylenebenzoate,
polybutylene-terephthalate as such or modified a little or
to a large extent by copolymerization or blending with
modifying agents, or polyamides with stiff sXeletons, for
example.
Examples of acid dye dyeable type fibers are
polyamides having -NH2 end groups and nylon 6, 66, 610 12
and PACMj for example, all of which are well known members
of this type.
Typical of the basic dyeable fibers are the ones
having -SO3Me (Me is metal) groups, especially -SO3Na group
or mixtures, and the like.
Fiber forming polymers having the a~ove-mentioned
groups include acrylonitrile copolymers, or
polyethylene-terephthalates or polybutylene-terephthalates
copolymerized or mixed with isophthalic acid sodium
~17-
~2~ 3
1034-83
sulfonate groups.
The direct or reactive dyeable fibers, the ones
having sufficient reactive groups, are exemplified typically
by fibers having -OH groups, including cellulose type and
polyvinylalcohol types as conventional fibers; fibers other
than these examples are of course included.
A mixture of at least two types of fiber bunclles
or multi-component fibers selected among the above-mentioned
groups may be used in the portion constituting the grained
surface.
Processes for making the mixture are generally
divided into the following three types described as follows
by reference to individual embodiments.
(l) Two ~inds of multi-core type fibers of the type
capable of producing a bundle of ultrafine fibers consisting
of cores having different dyeing properties, are mixed to
form the surface of the sheet. Optionally, the fibers may
be mix-spun or doubled with each other before use. In these
cases, in place of said multi-component type fibers,
bundles of ultrafine fibers obtainable by super drawing or
melt-blowing may be used as well.
An example of the present process includes mixing
two multi-core fibers whose island components are disperse
dyes dyeable with another core component which is bas:ic dye
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dyeable. The former core componen-t polymer is exemplified
by polyethylene-terephthalate and the latter by
copolymerized polyethylene-terephthalate with 1-~ wt %,
preferably, 2-5 w-t% of isophthalic acid sodium-sulfonate.
The process further includes multi-core fibers
whose core component is nylon 6 (the one including many
amino end groups and of the acid dyeable type) mixed with
the multi-core fiber of the above-mentioned basic dyeable
type.
The mixing ratio (ratio between individual core
components) may be determined arbitrarily, being selected in
the range of about ] to 99~ by weight according to the
purpose. The range of about 5 to 95% by weight can yield a
remarkable effect. In general the ratio of fibers
presenting a deeper color may preferably be kept at not more
than about 50% by weight.
The multi-component type fiber used in the present
invention does not require that the core component shall be
completely surrounded by the sea component. Both components
may be mutually clad in parallel, such as in the so-called
separable types of multi-component type fibers. In any
case, the sea component is separated and at least the core
component or the component corresponding to the core
component is used principally.
--19--
.~
1034-83
Although, when using the multi-component type
fiber, the step of making the fiber ultraine is carried out
at an appropriate time before or after foxmation of the
sheet, it is preferably conducted after formation of the
fiber sheet according -to the present invention, because of
favorable processability and the possibility of producing a
flexible artificial leather.
(2) As an application of case (l), another
process is applicable in which, in place of mixing ultrafine
fibers with each other, the other fiber to be mixed is
composed of a fiber (thick fiber) other than the ultrafine
denier fiber specified, as well as of a fiber which has
different dyeing properties than those of the ultrafine
fiber.
(3) Next, a preferable feature of the presen-t
invention consists of the use of a three-component type of
multi-core fiber that contains two kinds of core components
which differ in dyeing properties, which are deposited on
one side and the other side respectively, which structure
generates two kinds of ultrafine fiber bundles. Fig. 3(a~
shows an example of such fibers. In Fig. 3(a) reference
numerals l and 2 represent two kinds of core components
which differ in dyeing properties, and reference numeral 3
represents a binding component. This fiber is spun by a
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three-component composlte spinning machine, and a bundle of
fibers, in which two kinds of ultrafine flbers different in
dyeing property are mixed, is obtained by removal of one
component. Since said fiber already comprises a mixture, it
requires no further yarn doubling and mixing, which in some
cases may be carried out.
The multi-component type fiber that the present
invention covers includes many different fiber cross
sections, including the concept of making two kinds or more
of ultrafine fibers by removing one component from a fiber
of the separate or split-type consisting of three
components.
Another process for obtaining a fiber bundle, in
which two kinds of ultrafine fibers which differ in dyeing
properties are mixed, includes a process in which two
component type fibers such as those shown in Fig. 3(b), any
of whose constituent components is not removed, is made
ultrafine by separating or splitting. Typical of this
process is the use of the split type multi-component type
fiber consisting of polyamide and polyester. However, the
latter has the disadvantage of difficulty of changing the
mixing ratio to a large extent. This differs from the case
of the previously described three components type. Changing
the cross section increases the fibrillating efEect of the
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~2~ 3
1034-83
high speed fluid treatmen-t and often causes difficult
separation and splitting. When the polyamide component is
-treated with a solution containing a chemical to facilitate
separation and splitting, it sometimes becomes difficult to
obtain the effect of the present invention, for the following
reasons: considerable change in the dyeing characteristic;
embrittlement, shrinkage, and easy breaking during high
speed fluid treatment. This type of process further
includes a process of two colored yarn doubling ultrafine
spinning.
A combination of two or more processes of the
above-mentioned three processes may be used, of course.
In the foregoing three cases, there is a common
effect in the two colored dyeing of the surface or slight
difference in each effect. Comparisons of these three cases
are described below.
Regarding the general trend, the effectiveness of
the melange-colored, or aniline effect of surface is in the
order of (1), (2), (3) showing increasingly uniform
appeaxance in the above-mentioned order. In particular, the
closest uniformity generally results from (3). Various
melange-colored properties are obtainable, ranging from
components which are not so outstandingly different in color
to others that are. All have their own uses, and should be
-22-
31034-83
appreciated together.
An example of a process for preparing sheets
according to the present invention is as follows:
(1) Forming a sheet of two kinds of ultrafine
fibers which have different dyeing properties.
(2) Applyiny a jet to at least one side of the
sheet, the jet comprising a flow of high pressure fluid.
~ 3) Dyeing in different colors.
As to the order in which these process steps are
carried out, there are various possibilities without
limitation, as will be appreciated from an inspection of
Figs. S and 6 of the drawings. Treatment for making the
fibers ultrafine is needed onIy in the case of using a
multi-core fiber which is not yet ultrafine. The multi-core
component may, if desired, be made ultrafine at the same
time as the high speed fluid treatment or dyeing. Dyeing
may be performed, preferably at a time following formation
of the sheet.
It is ! of course, possible that transparent resin
layers may further be placed upon the melange-colored
surface. In this case, if a small amount of pigment or
dyestuff is applied to the resin layer to the extent that
the melange-color is at least partially visible through the
resin layer, the surface appearance presents more
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~Z~ 3
1034-83
complicated forms and creates a unique melange-colored
effect. One useful process for preparing a melange-colored
sheet according to the present invention is described as
follows:
Two kinds of multi-component type fibers (such as
Staple A and Staple B o Fig. 5) which differ in dyeing
properties as mentioned above are cut to a proper length,
mixed as staple fibers and formed into a web through such
processes as opening, carding and web forminy. Nex-t, the
web is needle-punched. By jetting at least one side of the
nonwoven shee-t with a jet of high speed fluid, as shown in
the upper processing route of Fig. 5, breakage of the sea
component and fibrillation and entanglement of the
fibrillated ultrafine fibers are carried out at the surface
of the sheet. Subsequently, the sea component is dissolved
and removed by the use of a liquid which is a solvent for
the sea component, but a non-solvent for the core component.
If necessary, the surface treated with a flow of high speed
fluid is subjected to molding under pressure or pressing to
form a grained-leather-like surface, followed by dyeing as
described later.
Another process is shown by the lower processing
route of Fig. 5. After producin~ a needle-punched nonwoven
sheet as heretofore described, the sea component is
-24-
1034-~3
dissolved and removed to make a sheet comprising ultrafine
fiber bundles. At least one side or both sides of said
sheet are then jetted with a high speed fluid and the
ultrafine fiber bundles at the surface are subjected to
fibrillation and entanglement to form a sheet having one or
both super-entangled suraces. Then, if necessaryJ the
surface is molded under pressure, followed by dyeing.
During or between these main process steps, any combination
of usual artificial leather preparation techniques may be
used. That is to say, the following techniques may be
combined: ~
The nonwoven fabric may be shrunk before or after
the high speed fluid jet treatment; resin liquid such as
polyurethane solution may be applied after the high speed
fluid jet treatment. The resin is applied to surround the
superentangled fibers or fiber bundles and followed by wet
coagulation or dry coagulation.
~ ig. 6 of the drawings shows various alternative
routes for making grained melange-colored surfaces, in which
a resin is applied to the superentangled ultrafine
melange-colored surface fibers of the sheet. The uppér
route of Fig. 6 shows application of polyurethane followed
by embossing to provide a grained pattern, followed by
dissolving the sea component. The middle route of F'ig. 6
-25-
33
103~-~3
shows use of a bi-polymer structure in which the individual
cores are mechanically separated by crumpling the sheet
after embossing, instead of dissolving out a sea component
as before. rrhe bot-tom route of Fig. 6 show, embossing after
the sea component has been dissolved out.
soth sides of rather thick nonwoven sheet may be
subjected to high speed fluid treatment and sliced during a
subsequent process; a temporarily-binding polymer such as
polyvinyl alcohol may be supplied before removal of the sea
component and later removed by extraction during the
subsequent process; resin liquid such as the solution of
temporarily-binding polymer and polyurethane elastomer may
be applied after the high speed fluid treatment, and may be
followed by wet coagulation or dry coagulation and
subsequent extraction (removal) of the temporarily-binding
polymer; appropriate resin is applied to the super-entangled
surface before the pressure molding or pressing.
Regarding the fluid used as the high speed fluid
jet, water is most preferred, but organic solvents or alkali
or acid solutions may be used according to the purpose.
Such fluid is pressurized by a high pressure pump and is
jetted through a nozzle of a small diameter or a slit having
a narrow gap against the surface of the nonwoven sheet in
the form of high speed columnar streams or a curtain stream.
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~2~ 3
1034-83
In the process in which jetting is carried ou-t before making
the ultrafine fiber bundle, a relatively high pressure
condition is preferred such as one ranging from about 70 to
300 kg/cm , because both effects are needed including
breaking the sea component or peeling off the sea component
to make fibrils of the fibers, and super-entangling the
fibrillated fiber surfaces.
On the other hand, in jetting after the ultrafine
fiber bundle has been made, a relatively low pressure
condition is sufficien-t, a satisfactory range being of the
order of about 5 to 200 kg/cm , because breaking the sea
component or peeling off the constituent component are not
required. In order to avoid development of impact locus due
to jetting, it is effective to oscillate the jet nozzle or
sheet relative to one another, or to repeat the jet
treatment a number of times.
sy jetting with high speed fluid, the fibrous
portlon at or near the surface is effected by the jet stream
and the fibers are divided and branched out into fibrils of
ultrafine fibers and said fibrils are entangled to produce a
superentangled surface having an extremely high density.
The dyeing process according to the present
invention includes a single-bath dyeing process and a
multi-bath dyeing process. These features and the manner in
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1034-83
which they may be carried out are as follows:
The one-bath dyeing process can shorten the dyeiny
period but involves problems of formation of precipita-tes by
reaction between different kinds of dyestuffs. Further,
contamination is encountered due to the presence of
different kinds of dyestuffs. Hence it is necessary to use
a limited combination of dyestuffs and to use
anti-precipitants. However, since contaminated dyestuffs
cannot be completely eliminated, the problems of clarity of
color and fastness of dyeing remain, and there are
limitations in depth, lightness and clarity of color. In
the multi-bath dyeing process, there is no fear of formation
of precipitates, and further, the process has the advantage
of providing clear colors and dyeing fastness by adopting
the so-called intermediate cleaning process.
The process called the one-bath multi-stage dyeing
process is included within the meaning of the expression
"one-bath dyeing process" according to the present
invention. It has properties intermediate the one-bath
dyeing process and the multi-bath dyeing process. Both
processes are conventional per se and the process of the
present invention may be carried out in accordance with
either of them. It is necessary, however, to select a
combination of dyestuffs which are dyed into two colors or
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1034-83
two color shades, as will be discussed in cletail.
One of the preferable embodiments of the present
invention is to dye the sheet which contains fibers having
different dyeability, with only one type of- dye. In such a
case, some fibers are dyed and the others remain undyed
(colorless) to show a melange effect. Three or more
components of fiber bundles or ultrafine fibers can also
been used, with separate, sequential dyeing steps to obtain
the desired number of colors in the melange effect.
As used herein the expression "melange colors't
means that there is a difference in main wavelength between
two colors, after being measured by a co]or difference meter
or the like. This difference should not be less than about 5
m, preferably not less than about 10 m. However, even when
the difference between main wavelengths is smaller than 5
m, or a remarkable difference between deep and light colors
can be visually recogni~ed, the effect is intended to be
included in the expressions "melange colors" or
"melange-colored surface" as used in the present inventionO
In this case, the criterion is that two kinds of colored
fibers can be distinguished with the naked eye.
A grained sheet having a melange-colored surface
of the present invention has a variety of uses such as
clo-thing, industrial use, furniture, wall decoration and
~29--
:,
3LZ~04~3
103~-83
interiors. In this connection various additional processing
steps may be applied, such as coa-ting with finishing resin,
repelling water, rubbing and scuffing and the treatment such
as thickness adjusting process including slicing and
buffing. In particular, it can he effectively utilized in
fields where emphasis is especially placed on tints of
color.
Examples according to the present invention appear
below; the present invention is not limited or restric-ted
thereby. Parts and percentages are all by weight.
EXAMPLE 1
Two different multi-core fibers were prepared:
(1~ Staple A of 51 mm length having about 12
crimps/in, which had a denier of 3.8 after drawing and which
was a multi-component type fiber consisting of 60~ of core
component (the number of cores was 72 filaments) composed of
copolymerized polyethylene-terephthalate with 2.4 wt/~ of
isophthalic acid sodium sulfonate and 40% of a sea component
composed of polystyrene.
(2) Staple B of about 51 mm length and having a
crimp of about 9 to 12 crimps/in, was a multi-component type
fiber consisting of 80~ of core component having a denier of
4.5 after drawing, (the number of cores was 72 filaments)
and composed of poly ~-caproamide having an amino end group,
-30-
. ,.~,,
4~93
1034-83
as core component, and 20~ of a sea component composed of
polystyrene.
Equal amounts of Staples A and B were subjected to
mixing, carding, cross lapper processing and needle punching
(3500 needles/cm2), in that order. A needle-punched felt
having a weigh-t of 530 g/m2 was obtained.
Both sides of said needle-punched felt were jetted
with columnar streams of water ejected at a pressure of 100
kg/cm2 through jet nozzles having apertures arranged along a
line and having a diameter of 0.1 mm and a distance pitch of
0.6 mm between the centers of the apertures. The jet
treat~ent was repeated four times, each followed by drying.
~ext, after being impregnated with a 5~ dimethylformamide
solution of polyester type polyurethanes, the sheet was
dried after wet coagulation with water and was treated with
trichloroethylene. The polystyrene of the sea component of
both multi-core fibers was thus removed.
The sheet was sliced into two pieces. The jet
treated surfaces of said both sheets were coated ~4g/m2)
with a two-pack polyurethane solution using a gravure coater
and were embossed at 160C by embossing rolls on which a
grain pattern for leather was carved, and a raw sheet having
a grained surface was obtained.
The grained sheet was dyed as follows:
~31~
1034-83
(1) One-bath dyeing conditions were used. (A/B =
50/50, on a fiber basis after removal of the sea component).
Dyeing with a cationic dye and an acid dye in the
same bath was conducted according to the following
conditions:
Cathilon Red CD-RLH 3%
Kayanol Milling Blue-GW 3%
Ospin KB-30F (manufactured by 4%
Tokai Seiyu)
Acetic acid (90%) 0.5 cc/Q
Anhydrous Glauberls salt 40 g/Q
Bath ratio 1 : 50
Dyeing temperature and time 120C x 60 min~
After dyeing, the contaminated dye was soaped out
under the following conditions:
Sundet G-29 1.0 g/Q
(Manufactured by Sanyo
Chemical Industries, Ltd.)
Acetic acid (90%) 0.5 cc/Q
Bath ratio l : 50
Treatment temperature and time 70C x 20 min.
In order to improve the dyeing fastness of the
acid dye, ixing was carried out under the following
conditions:
-32-
,~.
1034 83
Nylon Fix TH 4%
(Manufac-tured by Nippon
Senka Kogyo)
Formic acid 1%
Bath ratio 1 : 50
Treatment temperature and time 80C x 20 min.
(2) Two-bath dyeing (A/B = 10/90, on a basis
after removal of the sea component).
Using cationic dyestuff, the side composed of
isophthalic acid sodium sulfonate copolymer with
polyethylene-terephthalate was dyed under the following
conditions:
Cathilon Black CD-BLH 18%
Ospin KB-30F 4%
Acetic acid 0.S cc/Q
Anhydrous Glauber's salt 40 g/~
Bath ratio l : 50
Dyeing temperature and time 120C x 60 min.
After dyeing the copolymerized polyethylene
terephthalate with the isophthalic acid sodium sulfonate,
for removing cationic dyestuff contaminated on the poly-E
-caproamide side, cleaning was effected under the following
conditions:
Sodium hydrosulfite 2.9 g/~
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~Læ~493
1034-83
Soda ash 1.0 y/Q
Sundet G-29 1.0 g/Q
Bath ratio 1 : 50
Treatment temperature and time 70C x 20 min.
Next, the poly--caproamide side was dyed with the
acid dyestuff under the following conditions:
Mitsui Nylon Black GL 2
Ospin KB-30F 4~
hmmonium sulfate 4 g/Q
Bath ratio 1 : 50
Dyeing temperature and time 98C x 60 min.
After dyeing, soaping was carried out under the
following conditions:
Sundet G-29 1.0 g/Q
Acetic acid 0.5 cc/Q
Bath ratio 1 : 50
Treatment temperature and time 70C x 20 min.
Thus the grained surface of the grained sheet of
the present invention, obtained by use of the one-bath
dyeing conditions under (l), presented a melange-colored
surface which looked violet in color from a distance but
which had the appearance at a short distance of sober and
high grade colors containing randomly mixed red and blue
colors. This was a grained sheet with a true natural
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,p .
1034-83
sensation; even after being abraded with sandpaper the
surface suffered only slight ~laws and the color tone still
remained superior in comparison with conventional artificial
leather having a polyurethane film. The Lat-ter, when
abraded, had a poor appearance as a result of peeling of the
polyurethane film.
The grained sheet of the present invention, as
produced by the two-bath dyeing conditions under (2), also
had a sober melange-colored grained surface having as a
whole a grey tone containing mixed grey and black colors.
Further, the distance between fiber entangling points in the
grained surface layer was 80 microns.
EXAMPLE 2
The following mixture was prepared:
(l) Staple A of 51 mm length having 4.0 denier
with crimps; it consisted of a multi-core type fiber; the
core component was polyethylene-terephthalate containing
0.05% of titanium oxide, the core component content was 80~,
the number of cores was 36 filaments, and the sea component
was 20~ polystyrene.
(2) Staple B having the same constitution as (1)
of Example l, but the number of cores was 36 fllaments.
By subjecting staple A and staple B to mixing so
that the core ratio after removal of the sea component was
-35-
1034-83
60/40, a needle-punched felt of about 250 g/m2 was obtained
by the same procedure as in Example 1.
After being treated wi-th an aqueous solution of
polyvinyl alcohol and dried and shrunk, the needle-punched
felt was treated with perchloroethylene to dissolve out the
polystyrene sea component. Next, after showering with hot
water to remove the polyvinyl alcoh`ol, the following
treatment was repeated three times, following by drying:
the surface of one side was jetted with oscillation with
high pressure water streams at a pressure of 60 kg/cm2
through a nozzle which had a hole diameter of 0.09 mm. The
holes were arranged in one row at an interval of 0.6 mm.
Subsequently, after the surface portion of the resulting
sheet had been impregnated with a 10~ polyurethane emulsion
solution and dried, the surface was subjected to embossing
at 140C by embossing rolls on which a grain pattern was
carved, and a raw sheet having a grained surface was
obtained. Under the following conditions the resulting
material was subjected to a dyeing treatment in which a
disperse dye and a cationic dye were used in the same bath.
The conditions were:
Sumi~aron Red E-FBL 10
Astorason Blue GL 5~
Acetic acid (90~) 1.0 cc/Q
~36-
1034-83
Sodlum acetate 0.15 g/Q
Anhydrous Glauber's salt 3.0 g/Q
Sumipon TF (Manufactured by 1.0 g/Q
Sumitomo Chemical Co., Ltd.)
Bath ratio l : 50
Dyeing temperature and time 120C x 60 min.
After dyeing, reduction c~leaning was conducted
under the following conditions:
Sodium hydrosulfite 2.0 g/Q
Soda ash 1.0 gj~
Amylasine D l.0 g/Q
Bath ratio 1 : 50
Treatment temperature and time 70C x 20 min.
The grained layer in the present example, obtained
through hot water cleaning and water cleaning carried out
thoroughly after reduction cleaning r had a mean distance of
160 microns between fiber entangling points. The grained
sheet had a sober melange-colored surface of violet tone,
and when viewed closely the red and violet coloxs were
finely mixed. This product a]so achieved an important
object of the present invention, that is, the surface was
free of any vinyl or rubbery feeling and provided the same
natural sensation as natural leather. The melange-colored
tone was retained even after abrasion.
-37-
lQ34-83 ~2~
EXAMPLE 3
Fibers were prepared under the following
conditions~
(l) 50 par-ts of copolymerized polyethylene
terephthalate/5-sodiumsulfoisoph-thalate copolymer (weight
ratio: 97.6/2.4) and 50 parts of copolymer of styrene and
higher grade alcohol ester of acrylic acld (80/20) were
blended in the molten state and spun. Staple A (51 mm, 4.0
denier) having a multi-core construction (core component:
polyester, sea component: copolymer) was obtained in the
ordinary way.
(2) Staple B ( 51 mm, 4.0 denier) was obtained in
a similar way as Staple A except that the core component was
poly-~- capramide.
Both staples were subjected to mixing (A/B =
60/40) and to temporary needle punching using 500
needles/cm2 after web formation through oarding and cross
lapping to make a felt.
On the other hand, the mixture of Staple A and
Staple B in Example 2 were similarly subjected to temporary
needle punching using 500 needles/cm2 to make a felt. Both
felts were superimposed upon each other, and were further
needle punched using 1500 needles/cm2, on both sides. A
layered felt having a weight of 450 g/m2 as a whole was
-38-
1034-83 ~ 3
obtained.
In the same manner as Example 1, said felt was
subjected to high pressure water stream txeatment on both
sides, to polyurethane impregnation and to sea-removal, and
was finished except without slicing. A sheet having
super-entangled surfaces on both sides was obtained.
When thls product was dyed, using a one-bath
dyeing condition according to (1) of Example 1, one surface
had a melange-colored tone in which red and blue were mixed
as in Example 1, and the other surface had another
melange-colored tone in which red was mixed with whi-te color
(colorless). The resulting grained sheet, the sides of
which had different melange-colored tones, was suitable as a
reversible material.
Furthermore, two different melange-coiored tone
grained sheets were obtained by slicing. The distance
between fiber entangling points was 55 microns.
Next, thin polyurethane layers (containing 0.~
carbon black) of 10 microns thickness were formed on both
surfaces with a gravure coater. Both surfaces changed into
a deep and sober tone while maintaining a melange color
visible through the polyurethane layers.
EXAMPLE 4
_.
The following two kinds of multi-core fibers were
-39-
,
1034-83
prepared.
(l) Staple A (51 mm in length, 4.0 denier) of
specific islands-in-a-sea type fibers (16 ~slands) which
have a large number of the extra-ultrafine cores in each
islands. The fibers are composed of 60 parts of copolymer
of styrene and 2-ethylhexylacrylate (80/2t)) as a binding
component, and 40 parts of nylon 6 as a extra-ultrafine core
component. The average size of the extra-ultrafine cores
was about 0.0003 denier.
(2) Staple B (51 mm in length, 4.0 denier) of
specific islands in-a-sea type fibers (16 islands) which
have a large number of the extra-ultrafine cores in each
islands. The fibers are composed of 60 parts of polystyrene
copolymerized with 20 mol ~ of 2-ethylhexylacrylate as a
binding component, and 40 parts of polyethylene
terephthalate as a extra-ultrafine core component. The
average size of the extra-ultrafine cores was about 0.0003
denier.
Staple A and B were mixed so that the core ratio
A/B after removal of the sea component was 30/70.
The mixed staples were passed through a card and a
cross lapper to form a web. The web was then needle-punched
using needles, each having one hook, so as to entangle the
specific island-in-a-sea type fibers with one another and to
-40-
1034-83
produce a non-woven fabric. The resulting non-woven fabric
had a weight of about 450 g/m and an apparent density of
0.18 g/cm .
The resulting non-woven fabric was then
impregnated with a 10~ aqueous dispersion of polyethylene
glycol (molecular weiyh-t 200) monolaurate and was
subseguently dried so as to plasticize the binding
component. A large number of columnar streams of water
pressurized to 100 kg/cm2 were jetted once to each surface
of the sheet using the same je-t nozzle as used in Example 1
while the nozzle was being oscillated, followed by drying of
the sheet.
Thereafter, the -sheet was repeatedly dipped into
trichloroethylene and sgueezed to extract and substantially
remove the binding component of the fiber. The sheet was
then dried and was dyed with acid dyestuff under the
condition according to second step of (2j of Example 1 using
a normal-pressure winch dyeiny machine. After a softening
agent was applied, the sheet was crumpled and finished.
The resulting leather-like sheet had a weight of
180 g/m2, and apparent density of 0.29 g/cm3/ showed a
melange-colored effect comprising dark gray and white
(undyed), and excellent flexibility. Both surface had also
supple and smooth touch like that of higher grade natural
-41-
~z~
1034-83
leather, in spite of containing no binder.
The average distance between the fiber entangling
points of the constituent fibers of both su:rf aces was
measured. It was found to be 25 microns.
-42- ~
