Note: Descriptions are shown in the official language in which they were submitted.
WO94/09195 2 ~ ~ 7 ~ Q ~ PCT/NZ93/00098
HIGH BULK, MWLTI-COMPONENT YARN
The present invention relates to the ~-ntlfacture of
yarns, threads, twines and like materials. More particularly
the invention relates to the manufacture of high bulk yarns
made from staple fibre material combined with continuous
filaments or pre-spun staple fibre yarns.
Our earlier patent entitled ''Im~lov~ments to Yarn
Spinning Processes" New Ze~lAn~ Patent No. 232390, describes
and claims a method of spi nn; ng high bulk yarns on a worsted
or ~emi-worsted spinning frame and modifications to the
spi nn i ng frame required to carry out the process method. ~he
method involves manipulating the fibres immediately before
the insertion of twi~t such that part of every fibre is
embodied in the tightly twisted core of the yarn, whilst a
second part of ev~Ly fibre is spun around the core with a
much reduced level of twist, relative to fibre extent, by
overf~i ng. Such a yarn, therefore, includes a core, spun
with a normal level of twist relative to the count of that
core, and a surro1~n~i ng sheath of relatively loosely twisted
fibre from which is derived the high bulk of the yarn. The
method of manufacturing this yarn, however, has the
disadvantage that very fine bulky yarns cannot be made.
In any spi nn i ng process there exists a lower practical
limit upon the number of fibres required in the cross-section
of the yarn for the spi nn i ng process to be continuously
operable without a high fre~uency of end breaks. In the
worsted spinning process the generally recognised minimum
SUBSTITUTE SHEET
WO94/U9l9~ 2147~~ PCT/NZ93/00098
number of fibres in the yarn cross-section is an average of
45 fibres. In the above-mentioned method for spinning high
bulk worsted yarns the stresses imposed on the yarn during
gpinning are carried primarily by the fibre twisted into the
core, whilst the fibre twisted into the bulky sheath is
incorporated too loosely to contribute to yarn strength.
Thus an average of at lesst 45 fibres is necessary in the
core of the yarn to en~ure an adequate Epinning performance,
whilst fibre in the bulky sheath contributes to the total
yarn count. In a yarn spun with 50% of the fibre
constituting the core and 50~ of the fibre constituting the
bulky sheath, the total number of fibres in the yarn cross-
section is at least an average of 90. In the example of a
worsted yarn spun from 22~m fibres a conventional yarn could
be spun to a 1 in~r density as fine as 22.5 tex, whereas a
high bulk worsted yarn, spun according to the method
disclosed in our New ZeAlAn~ Patent No. 232390 could not be
spun finer than 45 tex.
In another earlier WRONZ Patent entitled "Multi-
Component Yarn", New ZeAlAn~ Patent No. 225679, a method is
disclosed of producing in one operation a yarn comprised of
one strand of staple fibre twisted together with two
continuous filaments or pre-spun strands. The main advantage
of this method lies in its ability to spin much finer yarns
with as few as 20 staple fibres or less in the yarn cross-
section. In one example of a yarn spun by this method a yarn
was spun having an average of 26 fibres of a 29 ~m wool and
SUBSTITUTE StlEEl-
W094/09195 21~ 7 0 0 ~ PCT/N~93/0~98
two nylon continuous filaments of 4.2 tex each. The
resultant count of the yarn was 30 tex whereas a yarn spun
conventionally from this wool could not be spun finer than 39
tex.
This multi-compo~nt yarn has many advantageous
properties and end uses, particularly as a weaving yarn, but
it has one ma~or disadvantage in that it lacks bulk and it is
generally considered unsuitable for many applications in
knitting. The bulk of such a yarn is typically in the range
of 6-8 cm3/g, which is the volume occupied by one gram of
yarn measured at a pressure of 10 grams per square
centimetre.
An ob~ect of the present invention is to produce in one
operation a high bulk, fine count staple yarn by combining
the t~hnologies disclosed in our earlier New Zealand Patent
No. 225679 and New z~l~n~ Patent No. 232390.
A second ob~ect of the invention is to provide a method
of producing high bulk, fine count yarns comprising one
strand of staple fibre twisted together with one or more
continuous filament or pre-spun yarns in which one or more
filament or pre-spun yarns can be incorporated into the yarn
structure as a core or wrapping component or components,
relative to the staple fibre component.
A further object of the invention is to produce a high
bulk, fine count staple yarn in which at least a proportion
of the staple fibres is overfed into the yarn structure at
the point of twist insertion such that the overfed portion of
SU~ST~IJTE S~EET
WO94/09195 ~14 7 a ~ 5 PCT/NZ93/00098
staple fibre is caused to protrude in loops from the yarn
surface to constitute a bulky sheath of fibre.
A further object of the invention is to provide a yarn
structure in which one part of substantially every staple
fibre is incorporated into the core of the yarn and a second
part of substantially every staple fibre is overfed into the
bulky yarn sheath, such that the bulky sheath and the core
are mechAnically interconnected.
A further ob~ect of the invention is to provide a yarn
structure having a high initial modulus of extensibility such
that the yarn bulk is stable to the tensile stresses normally
imposed upon a yarn in further processing steps such as
win~ing~ weaving and knitting.
Yet a further ob~ect of the invention is to provide a
yarn manufacturing process which overcomes the above
mentioned disadvantages and is capable of producing fine
yarns having a high bulk characteristic.
According to a broadest aspect of the invention there is
provided a process for producing a yarn comprising staple
fibres twisted together with one or more filament or pre-spun
yarns on ring or other types of spi nn i ng frames or machines
which utilise any form of closed-end, long draft system, to
form a yarn structure, and in which a p o~olLion of the
staple fibre is overfed into the structure to provide a bulky
~heath of fibres twisted around a central core consisting of
the one or more filament or pre-spun yarns and a second
proportion of the staple fibre.
TI~UTE SHEET
WO94/09195 214 7 0 0 5 PCT/NZ93/00098
According to the present invention there is provided a
process for producing a yarn comprising staple fibres twisted
together with one or more filament or pre-spun yarns on ring
or other types of spinning frames or machines, and in which a
proportion of the ~taple fibre is overfed into the structure
to provide a bulky sheath of fibre twisted around a central
core consisting of the one or more filament or pre-spun yarns
and a second proportion of the staple fibre, the process
including the steps of:
mounting in association with a spinning machine one or
more p~ck~ges of single filament, multi-filament yarn or
pre-spun yarn and a driven roller means adapted to
control the feed of staple fibres between the front
rollers of a drafting system and a point at which twist
is first inserted between the fibres and filament or
pre-spun yarn;
dimensioning the roller means relative to the length of
the staple fibres and its surface speed relative to the
delivery speed of the front drafting rollers 80 that
part of each staple fibre is overfed into the staple
fibre strand forming the yarn;
feeAing one of the filament or pre-spun yarns to join
with the drafted staple fibre strand at the nip of the
front drafting rollers of the spinning machine and
fee~ing one filament or pre-spun yarn to ~oin with the
staple fibre strand and the first filament or pre-spun
yarn at any point between the nip of the front drafting
SUBSTIT~TE SHEET
W094/O919S ~I~ 7 0 ~ 5 PCT/NZ93/00098
rollers and downstream of the nip of the driven roller
means, or; --
feeding one fil~^nt or pre-spun yarn to ~oin with the
stable fibre strand at a point downstream of the point
of twist insertion.
According to a second aspect of the present invention
there is provided apparatus for producing yarn according to
the first aspect as hereinbefore described.
The package or p~ckAges of filament yarn can be silk, or
any other natural, man-made or synthetic filament. Any type
of pre-spun yarn may be used such as cotton or any other
natural, man-made or synthetic fibre yarn.
Further aspects of the invention will become apparent
from the following descriptions which are given by way of
example only.
Examples of the present invention will now be described
with reference to the accompanying diagrams in which:
Fiqure 1 shows in cro~s-section the basic elements of a
type of ring spi nn i ng machine including a design of apparatus
according to the present invention;
Figure 2 shows in plan the basic elements of a type of
ring spi nn i ng machine including a design of apparatus
according to the present invention;
Figure 3 shows in plan the basic elements of a type of
hollow spindle spinning machine including a design of
apparatus according to the present invention;
S~JBST~UrE SHEFT
WO94/09195 2 ~ ~ 7 ~ 0 5 PCT/NZ93/00098
Figure 4 shows in detail the yarn structure and the
paths occupied by a typical staple fibre and the two filament
or pre-spun yarns within the structure of a yarn spun on a
ringframe spinning machine; and
Figure 5 shows in detail the yarn structure and the
paths occupied by a typical staple fibre and the two filament
or pre-spun yarns within the structure of a yarn spun on a
hollow spindle spinning machine.
Referring now to Figure 1 a roving of staple fibre 1 is
delivered through a pair of back drafting rollers 2, and a
pair of apron rollers 3 and a pair of front drafting rollers
4 to emerge as a twistless strand fed over driven rollers 5
below which the yarn 7 is formed by the insertion of twist
and which passes on through a pig-tail guide 8 onto a package
9 mounted on a spindle 10, via a ring and traveller mech~ni~m
11. A first filament or pre-spun yarn 12 is fed in
con~unction with the roving 1 at low tension into the nip of
the front drafting rollers 4. A second filament or pre-spun
yarn 13 may also be fed at low tension into the nip of
rollers 4 but in spatial separation from the first filament
or pre-spun yarn 12 and the roving 1. Alternatively the
second filament or pre-spun yarn may be fed at low tension
into the nip of the driven rollers 5, in spatial separation
from the first filA~nt or pre-spun yarn 12 and roving 1, or
alternatively of the downstream rollers 5, these alternatives
being shown in broken lines.
SUBST~T~JTE SHEE-r
WO94/09195 PCT/NZ93/00098
2 ~ ~0~
In operation the spindle 10 rotates to insert twist into
the yarn structure 7 and to wind a formed yarn onto the --
r~ck~ge 9 by co-operation with the ring and traveller
mechAni Rm 11 . The twist inserted propsgates upstream in the
yarn as far as the nip of the driven rollers 5. The first
filament or pre-spun yarn 12 is fed in contact with, or very
close to, the roving 1 at the nip of rollers 4 and assists in
carrying the twistless strand of staple fibres across the gap
between the nips of rollers 4 and rollers 5 while bern~ing
twisted into the core of the yarn 7. Referring now to Figure
2, the second filament or pre-spun yarn 12 when fed into the
nip of rollers 4 i8 held in spatial separation from the first
filament or pre-spun yarn 12 and its associated roving 1.
Spatial separation is maint~in~ until downstream of the nip
of rollers S until it combines with the first filament or
pre-spun yarn 12 and the strand of staple fibres 1 by
becoming wrapped around that structure to form the yarn 7.
The driven rollers 5 are driven with a surface speed in
excess of that of rollers 4 by a proportion in excess of
unity, chosen according to the particular properties required
in the finished yarn 7. The rollers 5 are loaded to provide
a pressure at their nip which is sufficient to influence
staple fibres after the trailing ends of those fibres have ..
been released by the nip of rollers 4 during their pa~sage
through the system, but light enough to allow staple fibres
still nipped by rollers 4 and the filament or pre-spun yarns
to slip in the nips of rollers 5 without becoming excessively
~ BST~T~5TE SHEET
WO94/09195 21 4 7 0 ~ 5 PCT/NZ93/00098
~sxetched or broken. Once the trailing end of a staple fibre
~as been released from the nip of rollers 4 that fibre
becomes subject to the influence of rollers 5 only and is fed
forwards by and at the surface speed of rollers 5 to become
overfed into the yarn 7. The portion of a staple fibre fed
into the yarn 7 downstream of the nip of rollers 5 before its
tr~ i 1 i ng end is released by rollers 4 migrates by virtue of
tension in the spi nn i ng yarn 7 towards the core of that yarn.
The portion of a staple fibre overfed by rollers 5 is caused
to wrap loosely around the core of yarn 7 by virtue of the
overfeed and contributes to the bulky sheath.
The second filament or pre-spun yarn 13 may be fed into
the system at one of any of the three alternative position 13
shown in Figures 1 and 2, and it is always kept in spatial
separation from the first filament 12 and the staple fibre
strand 1 until a point i~ re~h~ downstream of the nip of
rollers 5. When fed into the nip of rollers 4 the second
filament or pre-spun yarn 13 is controlled at the surface
speed of rollers 4 to be fed into the yarn 7 under the
8pi nn i ng tension of the yarn 7 to become wrapped relatively
tightly around the core of the yarn 7. When fed into the nip
of rollers 5 the filament or pre-spun yarn 13 is controlled
at the surface speed of rollers 5 to become overfed into the
ysrn 7 and so becomes loosely wrapped around the core of yarn
7, contributing to the bulky sheath. When the filament or
pre-spun yarn 13 is fed at low tension into the yarn 7
downstream of the nip of rollers 5 it is caused to wrap
S~CT~TUTE SHEE~
WO94/09195 PCT/NZ93/00098
21470~
-- 10 --
around the core of yarn 7 under low tension but does not
contribute significantly to the bulky sheath. The choice of
position at which the second filament or pre-spun yarn 13 i5
fed into the system is determined by the properties required
in the finished yarn 7.
In another alternative the yarn 7 may be spun by
including one only of the two filament or pre-spun yarns 12
and 13, either as a core or a wrapping component. When yarn
i5 spun including only the filament or pre-spun yarn 12 as a
core compon~nt the filament or pre-spun yarn can assist in
carrying the staple fibre component from the nip of the front
drafting rollers 4 through the nip of rollers 5 and on into
the twisted yarn structure, and further contribute to the
tensile strength of the yarn 7. When yarn is spun including
only the filament or pre-spun yarn 13, fed at any of the
alternative positions shown in Figure 1, the filament or pre-
spun yarn 13 is caused to wrap around the yarn 7, assisting
in bin~ing the staple fibres within the yarn structure and
contributing to the tensile strength of the yarn 7.
Referring now to Figure 3 a roving of staple fibres 1 is
processed through a drafting system as described previously
to be delivered via front drafting rollers 4, a pair of
delivery rollers 17 to be wound into a package 18 driven by a
scroll roller 19. The hollow spindle 14 has at its lower end
mech~ni~m 16 designed to grip the yarn with low force
sufficient to rotate the yarn, inserting false twist upstream
to the nip of rollers 5, but light enough to allow the yarn 7
SU~STITUTE SHEET
21 4~5
WO94/09l95 - PCT/NZ93/00098
to be drawn through the mech~nis~ 16 by the delivery rollers
- 17 without significantly stretching or br~ki ng the yarn 7.
Mounted on spindle 14 is a package 15 of a second
filament or pre-spun yarn 13 which rotates with spindle 14.
The filament or pre-spun yarn 13 combines with the forming
yarn 7 by wrapping around yarn 7 under the tension of the
balloon formed in the filament or pre-spun yarn 13.
Downstream of the yarn gripping mech~nism 16 there is
substantially no twist between the staple fibres in yarn 7,
but there is twist between the filament or pre-spun yarn 13
and the yarn 7 by virtue of the former wrapping around the
latter.
The driven rollers 5 are driven at a surface speed
greater than that of the front drafting rollers 4 to ove~feed
the tr~il ing portions of staple fibres into the yarn 7 as
previously described. A first filament or pre-spun yarn 12
is fed at the nip of rollers 4, also as previously described,
to become incorporated into the core of yarn 7 and assist in
carrying the staple fibres from the nip of rollers 4 to the
point at which the structure is wrapped by the filament or
pre-spun yarn 13.
Alternatively yarn may also be spun as hereinbefore
described on a hollow spindle machine, but including only one
or either of the two filament or pre-spun yarns 12 and 13.
Referring now to Figure 4 there is illustrated the path
in the yarn structure of a typical staple fibre 20 showing
the leading end of the fibre firmly twisted into the yarn
SUBST~TU~E SHE~:T
W O 94/09195 2 ~ 4 7 ~ ~ ~ PC~r/NZ93/00098 ~
- 12 -
core with its trailing end loosely twisted into a sheath
around the core in a yarn produced according to a first --
aspect of the invention including two filament or pre spun
yarns 12 and 13. The trailing end i8 then twisted into the
yarn with a lower twist per unit fibre length. ~he first
filament or pre-spun yarn 12 is shown, as a full line,
embedded within the core of the yarn structure, and the
second filament or pre-spun yarn 13 is shown wrapping the
structure, for yarns spun as hereinbefore described on a
ringframe. The twist angle of fibres lying on the surface of
the yarn is the same twist angle as that of the second
filament or pre-spun yarn 13.
Referring now to Figure 5 there is illustrated the path
in the yarn structure of a typical staple fibre 21 showing
the l~ing end of the fibre firmly emhe~A in the yarn core
with its trAi 1 ing end bulging in loops from the yarn surface
in a yarn produced on a hollow spindle spi nn i ng machine
according to a first aspect of the invention including two
filament or pre-spun yarns 12 and 13. The first filament or
pre-spun yarn 12 is shown in a full line embedded within the
core of the yarn, and the second filament or pre-spun yarn 13
is shown wrapping the structure. In this yarn structure
there is no twist between the staple fibres themselves or
between the staple fibres and the first filament or pre-spun
yarn 12; these lie in substantially parallel relationship
within the core of the yarn. Twist exists between the whole
of this structure and the second filament or pre-spun yarn 13
SUBST~TUTE SHEET
WO94/09195 214~ 0 0 5 PCT/NZ93/00098
- 13 -
by virtue of the second filament or pre-spun yarn being
wrapped around the structure. The trailing ends of the
staple fibres overfed into the yarn structure are slso bound
to the yarn structure by the wrapping filament or pre-spun
yarn 13 forming loops of fibre protruding from the yarn
surface between wrapping points. In this yarn structure the
protruding fibre loops are very stable, being securely
anchored by the wrapping component 13, and contribute to the
bulky sheath surrolln~i ng the yarn core.
In one example of yarn spun on a worsted ringframe by
the method described in WRONZ New ZeA1~n~ Patent
specification No. 225679 a 28 ~m blend of wool was drafted to
a strand of l in~r density of 18.5 tex and twisted together
with two filament yarns of l in~r density 2.2 tex each, with
680 tpm, to achieve a finished yarn linear density of 22.9
tex, and having an average of 23 staple fibres in the yarn
cross-section. The bulk of this yarn was measured, after
fully rel AYi ng by steaming a hank of the ysrn in an autoclave
for 2 minutes at 100C, and found to be 7.47cm3/g. The same
yarn structure was then spun by the method described in NRONZ
New zeAl ~n~ Patent No- 225679 but with the addition of the
driven roller meanæ described in WRONZ New z~l ~n~ Patent No.
232390 to generate yarn bulk, all with 825 tpm twist. In
this example the driven roller means (5 in Figure 1) was
driven at a surface speed 70% greater than that of the front
drafting rollers (4 in Figure 1). The bulk of this yarn was
measured, after fully rel~i ng a hank of the yarn by steaming
SUBSTiTU~E S~EET
2~4~
WO94/09195 PCT/NZ93/00098
- 14 -
in an autoclave for 2 minutes at 100C, and found to be
11.20cm3/g. -
In a second example the same 28 ~m wool used for the
first example was spun on a hollow spindle m~ch;ne to a
lineAr density of 22.0 tex which included two filA~-nt yarns
of 2.2 tex each and a strand of staple fibre of 1 ine~r
density 17.6 tex and having 22 staple fibres in the cross-
section. One yarn was spun with 430 tpm twist and without
the use of driven rollers 5. After fully relaxing the yarn
by steaming a hank of the yarn in an autoclave for 2 minutes
at 100C the bulk was measured and found to be 24.4 cm3/g. A
similar yarn structure wss then spun using also the driven
rollers 5 snd after fully rel AXi ng a hsnk of the yarn in an
autoclsve for 2 minutes st 100C the bulk was measured and
found to be 27.7 cm3/g. In this example the driven roller 5
wss driven at a surface speed 57~ greater than that of the
front drafting rollers 4.
Thus by this invention there is provided a ysrn
manufscturing process cspable of producing fine yarns having
a high bulk chsrscteristic, comprising staple fibre snd
filament or pre-spun ysrns. The staple fibre component can
comprise as few as 20 fibres or fewer in the cross-section of
the ysrn under commercially viable conditions.
Psrticulsr exsmples of the invention hsve been described
and it is envisaged that improvements snd modificstions can
be msde without depsrting from the scope of the invention.
SVBSTI~UT~ SH~
