Note: Descriptions are shown in the official language in which they were submitted.
~89~3
Because of recent trends in the papermaking indus-
try to employ papermaking machines of enlarged size and in-
creased operating speed for the purpose of improving paper-
making efficiency, there is a requirement for papermaking
felts of enlarged size as compared with the conventional
papermaking felts~ In addition to the requirement for such
enlarged size, needle punched felts which are resistant to
yielding to the high nipping pressure applied to the felts by
press rollers and which have smooth and soft working sur-
faces are required to maintain stabilized size and shape of
the felts under high operating speed, to provide good squeezing
capability and to avoid marking on papers. Accordingly,
strong and relatlvely hard yarns are used for forming the
foundation fabrics of the papermaking felts and in most cases,
double layer fabrics or multiple layer fabrics are used, since
the foundation fabrics must be of sufficient thickness, and
they also have a requirement of non-compressibility for the
component yarns~ to provide sufficient capacity of dewatering
and containing a large quantity of water squeezed out from
wet papers. Furthermore, in order to avoid the vibration of
the press rollers, the foundation fabric of the felt must be
endless as well as seamless, therefore, the foundation fabrics
must be woven in the hollow weave construction. However,
weaving a multiple layer fabric of the hollow weave construction
with strong and relatively hard yarns is extremely difficult
and needs advanced skill, and also it is necessary to use a
special and heavy loom, since it is extremely difficult to
weave such a fabric of stable quality with an ordinary loom
for weaving fabrics and production of many faulty fabrics is
liable to result.
It is therefore an object of the invention to
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, .,
11~8~3
provide an improved needle punched papermaking felt.
It is a further object of the invention to provide
a method for making such a felt.
In accordance with the invention, a needle punched
papermaking felt comprises a plurality of layers of relatively
easily woven endless foundation fabrics consisting of syn-
thetic filament yarns, synthetic fiber spun yarns, synthetic-
natural fiber blended spun yarns or two or more kinds of those
yarns, and batts consisting of synthetic fibers and/or natural
fibers and being laid over one or both sides of said found-
ation fabric, wherein the component fibers are caused to be
entangled with each other by needle punching.
From a different aspect, and in accordance with the
invention, a method of manufacturing a needle punched paper-
making felt comprises weaving a plurality of relatively
easily woven endless foundation fabrics, setting up said
foundation fabrics to a needle punching machine under tension,
supplying and laying batts consisting of synthetic fibers
and/or natural fibers over said layers of foundation fabrics
while said layers of foundation fabrics are advanced, and
needle punching the combined layers of said foundation fabrics
and said hatts so that the component fibers are caused to be
entangled with each other.
The invention will be better understood by an
examination of the following description, together with the
accompanying drawings, in which:
Figure 1 is a fragmentary sectional view of a con-
ventional needle punched paperma~ing felt,
Figure 2 is a schematic side elevation of a needle
punching machine for manufacturing the needle punched felt
of Figure 1,
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1 ~58~3
Figure 3 is a fragmentary sectional view of a
needle punched papermaking felt of the present invention, and
Figure 4 is a schematic side elevation of a needle
punching machine for manufacturing the needle punched felt
of Figure 3.
As shown in Figure 1, the conventional papermaking
felt is manufactured by weaving a foundation fabric 1 of a
multiple layer construction with a special heavy loom, then
laying batts 2 of staple fibers over the foundation fabric 1,
and finally needle punching the hybrid layers of the foun-
dation fabric 1 and the batts 2 of staple fibers to cause the
component fibers to be entangled with each other. In the man-
ufacturing process for the conventional felts as shown in
Figure 2, an endless foundation fabric 1 of a multiple layer
construction is extended between a driving roller 3 and a
driven roller 4 with its upper side being set up horizontally
and with its lower side being loosened. A batt of staple
fibers conveyed by a lattice 5 is wound around the foundation
fabric 1 by a required number of turns while the layers of
batt 2 is subjected to the needle punchin~ operation of a
needle board 6. Such a conventional felt, however, inevit-
ably raises the manufacturing cost due to various unfavorable
reasons, such as the high cost of equipments due to the nec-
essity of using costly special heavy loom, and the necessity
of many hours and much expenses for training operators due to
requirement of advanced and skilled weaving techniques. This
invention was made to overcome those disadvantages. ~ccor-
ding to the present invention, relatively easily woven
foundation fabrics are wov~n with an ordinary loom for weaving
foundation f~bric% without using a special heavy loom, a
plurality of those relatively easily woven foundation fabrics
are heaped up, batts of fibers are laid over one or both sides
of the foundation fabric, and then subjècted to needle punch-
ing, thus providing a felt capable of a papermaking perfor-
mance the same or exceeding that of the conventional felt
easily and at a reduced cost, more particularly, this invention
relates to a needle punched papermaking felt, comprising an
endless~~foundation fabric consisting of a plurality of layers~
of relatively easily woven foundation fabrics consisting of
synthetic filament yarns, synthetic fiber spun yarns, syn-
thetic natural fiber blended spun yarns or two or more kindsof those yarns, and batts consisting of synthetic fibers
and/or natural fibers and being laid over one or both sides
of the foundatibn fabric, wherein the component fibers are
caused to be entangled with each other by needle punching,
and also relates to a method of manufacturing a needle punched
papermaking felt, comprising weaving a plurality of relatively
easily woven endless fabrics, subjecting said foundation
fabrics to a needle punching machine in layers under tension,
supplying and laying batts consisting of synthetic fibers
and/or natural fibers over said layers of fabrics while said
layers of foundation fabrics are advanced, and needle punching
the combined layers of said fabrics and said batts so that
the component fibers are caused to be entangled with each
other.
Referring to Figure 3 illustrating a needle punched
papermaking felt of the present invention, an outside found-
ation fabric 7 and an inside foundation fabric 8 each woven in
endless forms are laid one over the other batts 2 consisting
of synthetic fibers and/or natural fibers are laid over one
or both sides of the foundation fabrics. The component fibers
of the warps and wefts consisting the foundation fabric and
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~1~89~3
the component fibers of the batts are firmly entangled with
each other to form a felt construction. This felt construc-
tion is subjected to finishing processes such as a chemical
treatment or singeing when necessary. In the foundation
fabric as shown in Figure 3, all of the foundation fabric
are of the single layer fabrics in many cases, however, some
of them may be of multiple layer fabrics which can relatively
easily be woven and the rest of them may be of single layer
fabrics, for example, the foundation fabric may be woven
with one fabric of a single layer fabric and one fabric of a
double layer fabric instead of a fabric of a triple layer
fabric which is used in the conventional practice. The res-
pective weave constructions, component yarns, yarn densities,
length ratio and width ratio of the component fabrics are
selectively determined so that the properties and performance
of the foundation fabric can meet the requirements of the
papermaking conditions to which the foundation fabric is sub-
jected, namely, the dewatering ability, pickup performance,
dimensional stability, marking preventing capability, resis-
tance to tension and wear resistance, and also so that thesuperposed foundation fabrics are heaped up perfectly to each
other without stretching and slackening even if the contraction
or elongation of the foundation fabrics are caused by the
needle punching process. Generally, it is preferable to form
the outside foundation fabric 7 with yarns of superior
elasticity in a dense construction to provide a surface capable
of preventing the marking, whereas it is preferable to form
the inside foundation fabric 8 with non-compressible yarns in
a relatively coarse construction to provide the inside found-
ation fabric 8 with a capability of maintaining space underhigh compressive force and good dewatering ability. Synthetic
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1 ~8~3
spun yarns, synthetic-natural fiber blended spun yarns,
synthetic multifilament yarns or synthetic monofilament yarns
are used as to component yarns of the fabrics. Single
synthetic monofilament yarns or twisted synthetic monofilament
yarns are preferable particularly for the needle punched felts
used under high speed and high nipping pressure. These yarns
are used individually or in combination of different types~
Synthetic fibers of the polyamide system, polyester system,
polyacrylonitrile system, polyolefin system and polypropylene
system are used. Wool is used in most cases as the material
for the natural fiber, however, cotton and flax may be used.
Epoxy resin, phenol resin, melamine resin, formaldehyde resin,
polyamide resin, polyvinyl resin and polyurethane resin are
used for the resin treatment of the felts. Batts are formed
in one bo ten layers and are needled with foundation fabrics
while the layer of batts are being laid over the surface of
the foundation fabric, or further are needled several re-
quired times after the laying of batts has been completed to
cause the component fibers to be firmly entangled with each
other. A thin layer of the batt can be interposed between the
adjacent component fabrics. Such provision of a thin layer
of the batt contributes to enhancing the binding between the
component foundation fabrics as well as increasing the elastic-
ity of the felt. Synthetic fibers and natural fibers used
for forming the batts are staple fibers of the same kind of
the above mentioned yarns.
Needle punched papermaking felts according to the
present invention are manufactured by using a needle punching
machine as illustrated in Figure 4~ A plurality of foundation
fabrics woven by taking into consideration the weave con-
struction, component yarns, yarn density, length ratio and
width ratio as described hereinbefore, are laid one over the
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~ 158903
other and extended over the rollers of the needle punching
machine. The layers of the foundation fabrics are tightened
with a stretching roller 9 so that the outside foundation
fabric 7 and the inside foundation fabric 8 are tightened
and made to adhere to each other, and then turned slowly by
a driving roller 3 and a driven roller 4 along the guide
rollers 10. A batt of fibers is supplied continuously over
the surface of the foundation fabric 7 from a feed lattice
in required number of layers while the foundation fabrics 7
and 8 and the layers of the batt are subjected to needling
operation of a needle board 6. After a required number of
layers of the batt has been form~d over the surface of the
foundation fabric 7, the batt supply is interrupted. The
foundation fabrics and the layers of the batt are subjected
to further needling when required. Thus the component fibers
are caused to be entangled firmly with each other. When the - -
felt is required to be provided with a batt on the opposite
side of the foundation fabric, it is only necessary to turn
inside out and to repeat the same batt supplying and needling
procedure. When the felt is required to be provided with
thin layers of batts between the adjacen~ foundation fabrics,
the following process is put into the above mentioned process
that is first a single foundation fabric is subjected to the
batt supplying and needling process, then the batt supply is
interrupted after a thin layer of batt has been supplied over
the surface of the foundation fabric, then the first hybrid
layer of said first foundation fabric and said first thin
layer of batts is loosened and a second foundation fabric îs
laid over the first thin layer of batt formed over the sur-
face of the fir~t foundation fabric, then the foundationfabrics are tightened, and then the second thin layer of batt
and needling procedure is repeated. After the needling
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~ 15~a03
process, the felt is subjected to the conventional finishing
processes, such as chemical treatment and singeing, according
to the purpose.
It is obvious from what has been described herein-
before that, since the foundation fabric of the needle punched
papermaking felt of the present invention is formed by laying
a plurality of relatively easily woven foundation fabrics one
over the other, various foundation fabrics of different weave
constructions, component yarns and yarn densities can be
selectively combined to provide the foundation fabric with
papermaking properties according to the purpose. Accordingly,
the papermaking properties, such as dewatering ability, dimen-
sional stability, marking preventing property and wear resis-
tance, are the same with or superior to those of the convent-
ional papermaking felts. Furthermore, according to the present
invention, the cost of equipment is remarkably reduced, only
a reduced floor space for installing the machines is necessary,
and the training time is saved as the operators of ordinary
skill can meet the operating requirements, since the founda-
tion fabrics of the present invention can be woven with anordinary loom for weaving them without using special heavy
loom which is necessary for the conventional methods and only
the provision of a stretching roller for the needle punching
machine is necessary. When some special heavy loom have
already been installed, the weaving efficiency will be improved
when those special heavy loom are used for weaving relatively
easily woven foundation fabrics. Still further, even if
increased installation of loom is necessary for the purpose of
increasing the production, it is only necessary to install
ordinary loom for papermaking felt. Thus the present invention
is capable of remarkably reducing the manufacturing cost.
~ ~8903
Embodiment 1:
An outside foundation fabric was woven in an end-
less form with an ordinary loom by using polyamide staple
fiber/wool blended spun yarns of 5's in a construction of a
warp density: 60 ends/5 cm, weft density: 54 picks/5 cm,
length ratio: 103% and weave construction: 1/3 broken twill.
An inside foundation fabric was woven also in an endless form
with an ordinary loom ~y using polyamide monofilament yarns
of 1800 denier in a construction of a warp density: 50 ends/
5 cm, weft density: 42 picks/5 cm length ratio: 100% and
plain weave construction. I`he outside foundation fabric and
the inside foundation fabric were laid one over the other
and extended tightly on a needle punching machine as shown
in Figure 4. The foundation fabric and the layers of batts
of polyamide staple fiber/wool blended fibers were subjected
to needling while the batt was supplied over the surface of
the foundation fabric in five layers to form a felt. The
felt was subjected to five cycles of needling after the supply
of the batt had been interrupted, and then the felt was sub-
jected to the conventional drying process and singeing process.Thus a needle punched papermaking felt was obtained. The
respective water contents of wet papers after squeezing with
the needle punched felt of this embodiment and the conventional
needle punched felt comprising a single sheet of double layer
fabric of 1/3 broken twill weave outside and plain weave
inside were 56% and 5~O~ which verified the superiority of
the felt of the present invention to the conventional felt
in the dewatering ability. No mark was observed over the
surface of the s~ueezed paper. Furthermore the cost of equip-
ment was reduced remarkably, since the installation of anyspecial heavy loom was unnecessary.
1158903
Embodiment 2:
An outside foundation fabric was woven in an end---
less form with an ordinary loom by using polyamide staple
fiber spun yarns of 6's in a construction of a warp density:
56 ends f 5 cm, weft density: 50 picks / 5 cm, length ratio:
101% and plain weave construction. An inside foundation fabric
was woven in an endless form also with an ordinary loom by
using the twisted yarns consisting of two 840 denier
polyester monofilament yarns in a construction of a warp
density: 48 ends/ 5 cm, weft density: 40 picks/ 5 cm, length
ratio: 100% and plain weave construction. The outside found-
ation fabric and the inside foundation fabric were laid one
over the other and extended tightly on a needle punching
machine in the manner the same with that of Embodiment 1.
The foundation fabric and the layers of batt of polyamide
staple fibers were subjected to needling while the b~tt was
supplied over the surface of the foundation fabric in four
layers to form a felt. The felt was subjected to five cycles
of needling after the supply of the batt had been interrupted.
Thus a needle punched felt was obtainedO The dimensional
stability of this felt was extremely excellent, while the
dewatering ability was superior. The use of an ordinary
loom provided the same advantageous effect with that of
Embodiment 1.
Embodiment 3:
An outside foundation fabric was woven in an end-
less form with an ordinary loom by using the twisted yarns
consisting of two 420 denier polyacrylonitrile multifilament
yarns as warps and polyester staple fibers/wool blended spun
yarns of 5's as wefts in a construction of warp density:
62 ends/5 cm, weft density: 56 picks/S cm, length ratio:
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1 15~03
102% and weft backed weave construction which is a weave
construction that can ~e relatively easily formed as for multiple
layer fabric. An inside foundation fabric was woven by
using 1800 denier polyester monofilament yarns in a con-
struction of warp density: 48 ends/ 5 cm, weft density: 40
picks/5cm, length ratio: 101% and plain weave construction in
; an endless form. The outside foundation fabric and the inside
foundation fabric were extended tightly on a needle punching
machine in the same manner a~ described hereinbefore. The
foundation fabric and the layers of batts of polyester staple
fibers/wool blended fibers were subjected to needling while
the batt was supplied over the surface of the foundation
fabric in four layers, and then the foundation fabric was
turned inside out, then subjected to needling while a layer
of the batt was supplied over the inside surface of the oun-
dation fabric. The outside surface and the inside surface
of felt were subjected to additional two cycles of needling
respectively after the supply of the batt had been interr-
upted to cause the component fibers to be entangled firmly
with each other. The needle punched papermaking felt was
finished by melamine resin treatment. The water content of a
wet paper squeezed by this felt was 55%, which was smaller
by 2% as compared with that of a paper squeezed by a conven-
tional papermaking felt of the same specification except that
the foundation fabric of the felt was of a triple layer fabric
woven with a special heavy loom. The felt of this embodiment
was superior in the dewatering ability, excellent in the
dimensional stability and marking preventing property. This
embodiment also reduced the cost of equipment remarkably,
30 since the foundation fabric could be woven with an
ordinary loom.
~ 1589~3
Embodiment 4:
An outside foundation fabric was woven in an end-
less form with an existing special heavy loom by using epoxy
resin treated polyamide staple fiber/polyester staple fiber
blended spun yarns of 6's in a construction of warp density:
58 ends/5 cm, weft density: 54 picks/5cm, length ratio: 102%
and weft backed weave construction. An inside foundation
fabric was woven in an endless form with an ordinary loom
by using epoxy resin treated 1800 denier single twisted poly-
amide multifilament yarns in a construction of warp density:48 ends/5 cm, weft density: 40 picks/5 cm, length ratio:
100% and plain weave construction. First the inside found-
ation fabric was extended tightly on a nee~le punching machine
and subjected to needling while a thin layer of a batt of
polyester staple fiber/wool fibers was supplied, then loosened
and the outside foundation fabric was laid over the inside
foundation fabric carrying a thin layer of needle punched
batt, and then the foundation fabrics were retightened.
The fabrics thus combined were subjected to needling while
2~ ~our layers of the batts were being formed over the surface
of the outside foundation fabric~ The combined fabrics were
subjected to three cycles of needling after the supply of
the batt had been interrupted to finish the papermaking felt.
The component fabrics of the felt were made to adhere firmly
to each other. The felt of this embodiment had an elasticity
greater ~han that of the conventional felts, good dimensional
stability, whereas the dewatering ability of this felt was
approximately the same degree with that of the conventional
felts.
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