EP1565601A1

EP1565601A1 - A high shrinkage side by side type composite filament and a method for manufacturing the same

Info

Publication number: EP1565601A1
Application number: EP03774281A
Authority: EP
Inventors: Joon-Young Yoon; Young-Hwan Lee; Sung-Kwan Lee
Original assignee: Kolon Industries Inc
Current assignee: Kolon Fashion Material Inc
Priority date: 2002-11-26
Filing date: 2003-11-21
Publication date: 2005-08-24
Also published as: AU2003284739A1; US20060051575A1; TWI259853B; EP1565601A4; JP2006507421A; KR100667624B1; CN1717510A; KR20040047600A; TW200420764A; WO2004048650A1

Abstract

The present invention relates to a high shrinkage side-by-side type composite filament, wherein two kinds of thermoplastic polymers are arranged side by side type and a boiling water shrinkage (Sr2) measured by the method (initial load = notified denier x 1/10g, static load = notified denier x 20/10g) of clause 5.10 of JIS L 1090 is 20 to 75% of a boiling water shrinkage (Sr1) measured by the method (initial load = notified denier x 1/30g, static load = notified denier x 40/30g) of clause 7.15 of JIS L 1013. The side-by-side type composite filament. is made of two kinds of thermoplastic polymers having a number average molecular weight difference (ïMn) of 5,000 to 15,000 upon spinning and the composite filament is drawn and heat-treated so as to satisfy the following physical properties: Temperature area exhibiting 95% of maximum thermal stress (Tmax, 95%): 120 to 230°C Range of maximum thermal stress per denier : 0.1 to 0.4g/denier

Description

A HIGH SHRINKAGE SIDE BY SIDE TYPE COMPOSITE FILAMENT AND A METHOD

FOR MANUFACTURING THE SAME

TECHNICAL FIELD

The present, invention relates to a side-by-side type

composite (conjugate) filament which has a high elastic property

(shrinkage) even in a filament state, and to a method for

manufacturing the same.

More particularly, the present invention relates to a

side-by-side type composite filament, which can omit a

false-twisting process and can attain a fine denier filament since

it has a superior crimp even in a filament state where no

false-twisting treatment has been carried out, and to a method

for manufacturing the same.

BACKGROUND ART

Synthetic fibers have reached the level not inferior to

natural fibers in some properties owing to repeated technical

development in spite of their short history. But, the crimp

property is a property which is not easy for synthetic fibers to

exhibit and is being considered as an intrinsic property of

natural fibers such as wool.

As prior art methods providing synthetic fibers with crimp properties are (i) a method for manufacturing a different

shrinkage composite false twisted yarn by doubling,

false-twisting and heat-setting two kinds of synthetic fibers

(yarns) having a big difference in shrinkage properties, (ii) a

method for mixing a polyurethane fiber with an excellent crimp

property in a longitudinal direction and other synthetic fiber

upon manufacturing woven or knitted fabrics, and (iii) a method

for manufacturing a composite fiber by conjugated-spinning two

kinds of polymers.

Of these methods, the method for manufacturing a different

shrinkage composite false twisted yarn is a method that provides

a potential shrinkage difference by mixing, false-twisting and

heat-setting two kinds of yarns having a big difference in

shrinkage properties. That is to say, this method makes the best

of a difference between a strain in false twist areas and a residual

strain after untwisting, in which a core yarn is deformed relatively larger than a effect yarn to be mixed and crosslinked

with the effect yarn.

The different _. shrinkage composite false twisted yarn

exhibits a good elastic property due to a difference in elongation

between core yarns and effect yarns. But, the above method was

disadvantageous in that, since the appearance of crimps is uneven

and the binding force of core yarns and effect yarns is relatively small because it is dependent upon air texturing and the like,

one component yarn is released or removed by a physical force

applied during a after-process or the crimping property is

decreased.

In addition, the above method for manufacturing a different

shrinkage composite false twisted yarn was problematic in that

it is difficult to provide a fine fineness because two or more

kinds of yarns have to be mixed, and the process becomes

complicated and the manufacturing cost is increased because the

two or more kinds of yarns pre-produced have to be rewound and

combined again.

On the other hand, the method for mixing a polyurethane fiber

and other synthetic fiber upon manufacturing woven or knitted

fabrics was disadvantageous in that it is difficult to process

because the synthetic fiber is different from the polyurethane

fiber in physical and chemical properties. For instance, the

polyester fiber is dyed using a disperse dye while a polyurethane

fiber has to be dyed with an acid dye or a metal-containing dye.

Therefore, in a case that the polyester fiber and the

polyurethane fiber are mixed upon manufacturing woven or knitted

fabrics, there are many problems that, for example, it is

necessary to use a chlorobenzene or methyl naphthalene carrier

for dyeing, and the final product is weak to a chlorine bleaching agent and easily hydrolysable by NaOH.

Meanwhile, a synthetic fiber manufactured by a polybutylene

terephthalate (PBT) resin has a problem that they have to undergo

a false twisting process for improving elastic property because

of their lack of shrinkage in a filament state.

Accordingly, it is an object of the present invention to

provide a side-by-side type composite filament which has a

superior crimp property even in a filament state and thus requires

no false-twisting process.

DISCLOSURE OF THE INVENTION

The present invention provides a side-by-side type

composite filament which has a excellent shrinkage even in a

filament state which is not passed false-twisting process.

Additionally, the present invention provides a method for

manufacturing a high elastic side-by-side type composite filament

which has a simple process and can attain a fine denier filament

since a false-twisting process can be omitted.

To achieve the above objects, there is provided a high crimp

(shrinkage) side-by-side type composite filament according to the present invention, wherein two kinds of thermoplastic polymers

are arranged in side by side type and a boiling water shrinkage

(Sr₂) measured by the method (initial load = notified denier * 1/lOg, static load = notified denier x 20/10g) of clause 5.10 of

JIS L 1090 is 20 to 75% of a boiling water shrinkage (Sr^_.) measured

by the method (initial load = notified denier x l/30g, static load = notified denier * 40/30g) of clause 7.15 of JIS L 1013.

Additionally, there is provided a method for manufacturing

a high shrinkage side-by-side type composite filament according

to the present invention consisting two kinds of thermoplastic

polymers which are arranged in side by side type, wherein two kinds

of thermoplastic polymers having a number average molecular

weight difference (ΔMn) of 5, 000 to 15, 000 are used upon spinning and the composite filament is drawn and heat-treated so as to

satisfy the following physical properties:

• Temperature area exhibiting 95% of maximum thermal stress

(Tmax, 95%) : 120 to 230°C

• Range of maximum thermal stress per denier : 0.1 to 0.4g/denier

Hereinafter, the present invention will be described in

detail.

Firstly, in the present invention, a side-by-side type

composite filament is manufactured by conjugated-spinning two

kinds of thermoplastic polymers in side by side type and then drawing and heat-treating the composite filament spun by a

continuous or discontinuous process. Specifically, in the present invention, a side-by-side type

composite filament can be manufactured by a spin-direct draw

method which carries out spinning, drawing and heat-treating in

one process as shown in Fig. 1, or a side-by-side type composite

filament can be manufactured by conjugated-spinning two kinds of

thermoplastic polymers in side by side type to prepare an undrawn

or half-drawn composite filament and then drawing and

heat-treating the undrawn or half-drawn composite filament by a

discontinuous process as shown in Fig. 2.

The present invention is characterized in that two kinds

of thermoplastic polymers having a number average molecular

weight difference (ΔMn) of 5,000 to 15,000 are used upon conjugated spinning. The thermoplastic polymers include

polyethylene terephthalate, etc.

The polyethylene terephthalate is produced by an ester

interchange between ethylene glycol and terephthalic acid

dimethyl, or by polymerization between ethylene glycol and

terephthalic acid. At this time, if the polymerization time is

adjusted, a number (n) of chains of polyethylene terephthalte can

be adjusted, and a polyethylene terephthalte with desired

molecular weight can be obtained.

The number average molecular weight is a value measured by

Gel Permeation Chromatograpy (GPC) . If the number average molecular weight difference (ΔMn) between the polymers is smaller than 5,000, the difference in

degree of orientation between the polymers is insufficient and

thus the shrinkage ratio of the final product becomes lower. If

greater than 15, 000, the shrinkage ratio is superior but a serious

yarn swelling phenomenon occurs upon spinning due to an excessive

difference in number average molecular weight and the yarn

strength becomes lower to thereby make it difficult to set a stable

spinning condition.

The side-by-side type composite filament has such a shape

that two kinds of thermoplastic polymers are bonded each other

to form an interface dividing the filament into halves and its

cross section is a circular type, a rectangular type, a cocoon

type, etc.

The shape of the cross section is freely changeable according

to a cross section shape of a spinneret hole and a bonding method

of polymers, and the interface has a linear shape or a bow-like

curved shape according to a difference in melt viscosity between

polymers. Generally, a polymer having a low melt viscosity

surrounds a polymer having a high viscosity to form an interface

of a bow-like curved shape.

Meanwhile, the present invention is characterized in that

the finally manufactured composite filament is drawn and heat-treated so as to satisfy the following physical properties:

• Temperature area exhibiting 95% of maximum thermal stress

(Tmax, 95%) : 120 to 230°C

• Range of maximum thermal stress per denier : 0.1 to 0.4g/denier

' Preferably, the composite filament is drawn and

heat-treated so that the temperature distribution range of

maximum thermal stress of the finally manufactured composite

filament is 140 to 20^'0°C. If the temperature distribution range of maximum thermal stress is deviated from the above range, the

processibility may be deteriorated or the quality of woven or

knitted fabrics may be degraded.

Further, if the range of maximum thermal stress per denier

is smaller than 0. lg/denier, the appearance of crimps is degraded,

or if greater than 0.4g/denier, it becomes hard to control the

shrinkage.

Further, if the temperature distribution range of maximum

thermal stress is smaller than 140°C or the temperature area (Tmax,

95%) exhibiting 95% of maximum thermal stress is smaller than 120°C, the shrinkage becomes too large and thus the appearance of crimps

is degraded. On the contrary, if the temperature distribution

range of maximum thermal stress is greater than 200°C or the temperature area (Tmax, 95%) exhibiting 95% of maximum thermal stress is greater than 230°C, the drawing stability is degraded. In order for the drawn and heat-treated composite filament

to satisfy the physical properties, a temperature of heat

treatment . in a second Godet roller (6) is adjusted in the

spin-direct draw method of Fig. 1, and a temperature of heat

treatment in a hot plate (12) is adjusted in the method of drawing

and heat treatment by a discontinuous process as shown in Fig.

2.

The side-by-side type composite filament manufactured by

the above-mentioned method according to the present invention has

two kinds of polymers arranged side by side type and tends to have

a different boiling water shrinkage from that of a typical

composite fiber filament.

Generally, a synthetic fiber filament and a textured

synthetic fiber yarn (false-twisted yarn) have a different

condition for measuring a boiling water shrinkage from each other

due to their difference in crimp property. Specifically, since

the synthetic fiber filament has almost no crimp, the possibility

of an error according to a change of the condition of measuring

a boiling water shrinkage is relatively low. On the contrary,

since the textured synthetic fiber yarn (false-twisted yarn) has

relatively many crimps, the possibility of an error according to

a change of the measuring condition is relatively high. The boiling water shrinkage of the synthetic fiber filament

is mostly measured by the method (initial load = notified denier

x l/30g, static load = notified denier 40/30g) of clause 7.15

of JIS L 1013 while the boiling water shrinkage of the textured

synthetic fiber yarn (false-twisted yarn) is mostly measured by

the method (initial load = notified denier x 1/lOg, static load

= notified denier 20/10g) of clause 5.10 of JIS L 1090.

In the side -by-side type composite filament of this

invention, the boiling water shrinkage (Sr₂) measured by the

method of clause 5.10 of JIS L 1090 is 20 to 75% of the boiling

water shrinkage (Sri) measured by the method of clause 7.15 of

JIS L 1013.

In other words, in case of the side -by-side type composite

filament of this invention, the boiling water shrinkage (Sr₂)

measured under the condition of measuring the boiling water

shrinkage of a textured synthetic fiber yarn (false-twisted yarn)

is 20 to 75% of the boiling water shrinkage (Srj_.) measured under

the condition of measuring the boiling water shrinkage^' of a

synthetic fiber filament. On the contrary, in case of a general synthetic fiber

filament, the boiling water shrinkage (Sr₂) measured under the

condition of measuring the boiling water shrinkage of a textured

synthetic fiber yarn (false-twisted yarn) is 90 to 99% of the boiling water shrinkage (Sri) measured under the condition of

measuring the boiling water shrinkage of a synthetic fiber

filament, which is almost not different from a boiling water

shrinkage measured regardless of a measuring method.

As described above, the side-by-side type composite

filament of this invention is similar to a textured yarn

(false-twisted yarn) in the boiling water shrinkage behavior in

spite of its filament form, and is much superior to the textured

yarn in the crimp performance.

In the present invention, various physical properties of

the composite filament and of a woven or knitted fabric are

evaluated as below.

• Boiling Water Shrinkage (Sri an Sr ) and Crimp Recovery Rate (CR)

The boiling water shrinkage (Sri) was measured by the method

of clause 7.15 of JIS L 1013 and the boiling water shrinkage (Sr₂)

was measured by the method of clause 5.10 of JIS L 1090.

Specifically, a hank was prepared by winding a composite filament

around a creel 10 or 20 times (20 times in the method of clause

7.15 of JIS L 1013 and 10 times in the method of clause 5.10 of

JIS L 1090) . An initial load and a static load were applied to

the prepared hank to measure the length (L₀) . In the method of

clause 7.15 of JIS L 1013, the initial load equals to notified denier l/30g and the static load equals to notified denier

40/30g) . In the method of clause 5.10 of JIS L 1090, the initial

load equals to notified denier 1/lOg and the static load equals

to notified denier x 20/10g. The hank was heat-treated for 30

minutes in a hot water of 100°C ± 2°C, taken out, dewatered with a moist absorbent paper, and left indoors. Then, the initial load

and the static load corresponding to each of the methods were

applied again to the hank to measure the length (Li) . Continuously,

the hank with initial load and static load was left in the water

of 20°C + 2°C and then the sample length (L₂) was measured. The static load was removed again and left and then the sample length

(L₃) was measured. The measured values are substituted into the

following formula to calculate the boiling water shrinkage and

the crimp recovery rate.

Boiling water shrinkage (Sr_t and Sr₂)= X 100(%)

Lo

L₂-L₃

Crimp recovery rate (CR)= X 100(%)

L₂ • Elastic property of Fabric

It was evaluated by an organoleptic test using a panel

composed of 30 people. If 25 or more out of 30 people judges the

shrinkage of a fabric excellent, it is represented as ©. If 20

to 24 people judge it excellent, it is represented as O. If 10 to 19 people judge it _, excellent, it is represented as Δ . If 9

or less people judges it excellent, it is represented as x.

•Temperature (Tmax) Exhibiting Maximum Thermal Stress and Maximum Thermal Stress Per Denier (g/denier)

They were measured by a Thermal Stress Tester of Kanebo

Engineering Co. Ltd. Specifically, a loop-shaped sample having

a 10cm length was suspended on upper and lower hooks and then a

predetermined tension [notified denier of composite filament

^χ2/30g] was applied to the sample. In this state, the temperature

was raised at a predetermined speed (300°C/120seconds) . A stress change corresponding to a temperature change was drawn on a chart

as shown in Fig. 3 and then a temperature area (Tmax, 95%)

exhibiting more than 95% of maximum the thermal stress was

obtained with the maximum thermal stress as a center. The maximum

thermal stress per yarn denier was calculated by obtaining maximum

thermal stress on the chart and then substituting it into the

following formula.

Maximum Thermal Stress Maximum Thermal Stress Per Denier =

Notified denier of Composite Filamment *2

•Number Average Molecular Weight (Mn) and Weight Average Molecular Weight (Mw) They were measured using the gel permeation chromatograph

(GPC) method by the following formula:

Hi: length of signal of detector on baseline of retention

volume (Vi)

Mi: molecular weight of polymer fraction in retention volume (Vi)

N: number of data

Wherein the retention volume (Vi) is the volume of solvent

consumed during the retention time of sample component molecules

in columns .

The retention time is the time taken until the sample

component molecules enter the columns and melt out.

Since the results measured by the above method are relative

values, a standard material is used in order to compensate these

values. As the standard material, mainly used is polystyrene, of

which the molecular weight and the breadth of the molecular weight

distribution are already known. Other kinds of standard materials

also may be used on a proper basis.

The breadth of the molecular weight distribution is the width of the peak value of the molecular weight distribution and represents the dispersity (Mw/Mn) of a target polymer material.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic view of a process for manufacturing

a high crimp side-by-side type composite filament according to

the present invention by a spin-direct draw method;

Fig. 2 is schematic view of a process for manufacturing a

high crimp side-by-side type composite filament according to the

present invention by drawing and heat treatment an undrawn yarn

or a half-drawn yarn;

Fig. 3 is a thermal stress curve of the composite filament

of the present invention charted in a thermal stress tester;

Fig. 4 is a micrograph showing the cross sectional state

of the side-by-side type composite filament according to the

present invention;

Fig. 5 is a micrograph showing the state of the side-by-side

type composite filament before heat treatment according to the

present invention; and

Fig. 6 is a micrograph showing the state of the side-by-side

type composite filament after a hot water treatment (100°C) according to the present invention.

* Explanation of Reference Numerals for Main Parts in the Drawings

1,2: extruder 3: spinning block 4: quenching chamber 5: first Godet roller

6: second Godet roller 7: conjugate filament 8: draw winder 10: undrawn yarn or half-drawn yarn drum 11: hot roller

12: hot plate 13: draw roller 14: conjugate filament

Tg: initial shrinkage start temperature

Tmax: temperature exhibiting maximum thermal stress

Tα: lower limit value of temperature area exhibiting 95% of maximum thermal stress

Tβ: upper limit value of temperature area exhibiting 95% of maximum thermal stress

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is now understood more concretely by

comparison between examples of the present invention and

comparative examples. However, the present invention is not

limited to such examples.

Example 1

A polyethylene terephthalate with a number average

molecular weight (Mn) of 15,000 and a polyethylene terephthalate

with a number average molecular weight (Mn) of 25,000 are conjugated-spun in side by side type at a speed of 3,000m/min at

a temperature of 285°C. The resulting material is drawn and heat-treated at a draw speed of 650m/min and at a drawn ratio of 1.68 in a drawing and heat treatment process as shown in Fig. 2,

to prepare a side-by-side type conjugate (composite) filament

having 100 deniers/24 filaments. The drawing and heat-treatment

temperature (hot plate temperature) is set to 132°C so that the composite filament can satisfy the following physical properties .

Maximum thermal stress per denier: 0.21g/denier

Temperature exhibiting maximum thermal stress (Tmax) : 155°C Temperature area exhibiting 95% of maximum thermal stress

(Tmax, 95%) : 122 to 228°C Next, a five-harness satin with a warp density of 190

yarns/inch and a weft density of 98 yarns/inch is woven in a rapier

loom using the conjugate filament as a warp and a weft, then

scoured/contracted, then dyed in a rapid dyeing machine of 125°C, and then after-processed under a typical postprocessing condition,

thereby making a fabric . The results of measuring various physical

properties of the prepared side-by-side type conjugate filament

and of the fabric made thereof are as shown in Table 1.

Example 2

A polyethylene terephthalate with a number average

molecular weight (Mn) of 12,000 and a polyethylene terephthalate

with a number average molecular weight (Mn) of 25,000 are

conjugated-spun in side by side type at a speed of 3,000m/min at

a temperature of 285°C. The resulting material is drawn and heat-treated at a draw speed of 650m/min and at a drawn ratio of

1.68 in a drawing and heat treatment process as shown in Fig. 2,

to prepare a side-by-side type conjugate filament having 100

deniers/24 filaments. The drawing and heat-treatment temperature

(hot plate temperature) is set to 140°C so that the composite filament can satisfy the following physical properties.

Maximum thermal stress per denier: 0.31g/denier

Temperature exhibiting maximum thermal stress (Tmax) : 165°C Temperature area exhibiting 95% of maximum thermal stress

(Tmax, 95%) : 122 to 228°C

Next, a five-harness satin with a warp density of 190

yarns/inch and a weft density of 98 yarns/inch is woven in a rapier

loom using the conjugate filament as a warp and a weft, then

thereby making a fabric. The results of measuring various physical

properties of the prepared side-by-side type conjugate filament

and of the fabric made thereof are as shown in Table 1.

Example 3

A polyethylene terephthalate with a number average

molecular weight (Mn) of 16,000 and a polyethylene terephthalate with a number average molecular weight (Mn) of 28,000 are

conjugated-spun in side by side type at a temperature of 290°C. The resulting material is drawn and heat-treated in a continuous

drawing and baking process as shown in Fig. 1, to prepare a

side-by-side type conjugate filament having 100 deniers/24

filaments. The temperature of a first Godet roller is set to 82°C and the speed thereof is set to l,800m/min. The speed of a second

Godet roller is set to 4,815m/min, the speed of a take-up roller

is set to 4,800m/min, and the temperature of the second Godet

roller is set to 163°C, so that the conjugate filament can satisfy the following physical properties.

Maximum thermal stress per denier: 0.16g/denier

Temperature exhibiting maximum thermal stress (Tmax) : 175°C Temperature area exhibiting 95% of maximum thermal stress

(Tmax, 95%) : 122 to 228°C

Next, a five-harness satin with a warp density of 190

yarns/inch and a weft density of 98 yarns/inch is woven in a rapier

loom using the conjugate filament as a warp and a weft, then

thereby making a fabric . The results of measuring various physical

properties of the prepared side-by-side type conjugate filament

and of the fabric made thereof are as shown in Table 1.

Comparative Example 1 A polyethylene terephthalate with a number average molecular weight (Mn) of 21,000 and a polyethylene terephthalate

with a number average molecular weight (Mn) of 25,000 are

con ugated-spun in side by side type at a speed of 3,000m/min at

1.68 in a drawing and heat treatment process as shown in Fig. 2,

to prepare a side-by-side type conjugate filament having 100

deniers/24 filaments. The drawing and heat-treatment temperature

(hot plate temperature) is set to 118°C so that the composite -filament can satisfy the following physical properties.

Maximum thermal stress per denier: 0.21g/denier

Temperature exhibiting maximum thermal stress (Tmax) : 135°C Temperature area exhibiting 95% of maximum thermal stress

(Tmax, 95%) : 122 to 228°C _ Next, a five-harness satin with a warp density of 190

yarns/inch and a weft density of 98 yarns/inch is woven in a rapier

loom using the composite filament as a warp and a weft, then

thereby making a fabric . The results of measuring various physical

properties of the prepared side-by-side type conjugate filament

and of the fabric made thereof are as shown in Table 1. Comparative Example 2

A polyethylene terephthalate with a number average

molecular weight (Mn) of 20,000 and a polyethylene terephthalate

with a number average molecular weight (Mn) of 25,000 are

conjugated-spun in side by side type at a speed of 3,000m/min at

1.68 in a drawing and heat treatment process as shown in Fig. 2,

to prepare a side-by-side type conjugate filament having 100

deniers/24 filaments. The drawing and heat-treating temperature

(hot plate temperature) is set to 115°C so that the conjugate filament can satisfy the following physical properties.

Maximum thermal stress per denier: 0.18g/denier

Temperature exhibiting maximum thermal stress (Tmax) : 130°C Temperature area exhibiting 95% of maximum thermal stress

(Tmax, 95%) : 122 to 235°C

Next, a five-harness satin with a warp density of 190

yarns/inch and a weft density of 98 yarns/inch is woven in a rapier

loom using the composite filament as a warp and a weft, then

thereby making a fabric. The results of measuring various physical

properties of the prepared side-by-side type composite filament and of the fabric made thereof are as shown in Table 1.

Comparative Example 3

A polyethylene terephthalate with a number average

molecular weight (Mn) of 25,000 and a polyethylene terephthalate

with a number average molecular weight (Mn) of 25,000 are

conjugated-spun in side by side type at a speed of 3,000m/min at

a temperature of '285°C. The resulting material is drawn and heat-treated at a draw speed of 650m/min and at a drawn ratio of

1.68 in a drawing and heat treatment process as shown in Fig. 2,

to prepare a side-by-side type conjugate filament having 100

deniers/24 filaments. The temperature of a hot roll is set to 85°C and the drawing and heat-treatment temperature (hot plate

temperature) is set to 130°C so that the conjugate filament can satisfy the following physical properties.

Maximum thermal stress per denier: 0.18g/denier

(Tmax, 95%) : 122 to 235°C

Next, a five-harness satin with a warp density of 190

yarns/inch and a weft density of 98 yarns/inch is woven in a repia

loom using the composite filament as a warp and a weft, then

scoured/contracted, then dyed in a rapid dyeing machine of 125°C, and then after-processed under a typical postprocessing condition, thereby making a fabric . The results of measuring various physical

properties of the prepared side-by-side type conjugate filament

and of the fabric made thereof are as shown in^' Table 1.

[Table 1]

Results of evaluating physical properties of yarn and of fabric

In the above table, S i is a boiling water shrinkage of the

composite filament measured by the method of clause 7.15 of JIS

L 1013, and Sr₂ is a boiling water shrinkage of the conjugate

filament measured by the method of clause 5.10 of JIS L 1090.

INDUSTRIAL APPLICABILITY

The side-by-side type .conjugate filament of this invention is superior in crimp property, exhibits the same properties as natural fibers and is easy to carry out a dyeing process. Further,

the present invention reduces the manufacturing cost due to a simple manufacturing process and enables the composite filament to have a fine denier.

Claims

WHAT IS CLAIMED IS:

1. A high shrinkage side-by-side type composite filament,

wherein two kinds of thermoplastic polymers are arranged side by

side type and a boiling water shrinkage (Sr₂) measured by the

method (initial load = notified denier 1/lOg, static load =

notified denier 20/10g) of clause 5.10 of JIS L 1090 is 20 to

75% of a boiling water shrinkage (Sri) measured by the method

(initial load = notified denier x l/30g, static load = notified

denier x 40/30g) of clause 7.15 of JIS L 1013.

2. A method for manufacturing a high shrinkage side-by-side

type composite filament consisting two kinds of thermoplastic

polymers which are arranged side-by-side type, wherein the two

kinds of thermoplastic polymers having a number average molecular

satisfy the following physical properties:

• Temperature area exhibiting 95% of maximum thermal stress

(Tmax, 95%) : 120 to 230°C

• Range of maximum thermal stress per denier : 0.1 to 0.4g/denier

3. The method of claim 2, wherein the composite filament

is drawn and heat-treated so that the temperature distribution

range (Tmax) of the maximum the thermal stress of the composite

filament is 140 to 200°C.

4. The method of claim 2, wherein the thermoplastic polymers

are polyethylene terephthalate.

5.. A woven or knitted fabric containing the side-by-side

type composite filament of claim 1.