JP2003527497A - Manufacture of poly (trimethylene) terephthalate woven staples - Google Patents

Abstract

A process for making textile staple fibre from polytrimethylene terephthalate (PTT) which comprises: (a) melt extruding PTT polymer at 245 to 253 DEG C, (b) spinning the extruded PTT into yarn using at least one spinneret, (c) moving the spun yarn to a first takeup roll wherein the distance from the spinneret to the roll is from 16 to 20 feet, (d) cooling the spun yarn to less than 31 DEG C before it reaches the roll, (e) prior to the draw process, preconditioning the yarn under tension at a temperature of at least 60 DEG C, (f) drawing the yarn at a temperature of at least 60 DEG C, (g) allowing the drawn yarn to relax at a temperature of up to 190 DEG C, and (h) crimping the drawn yarn at a temperature of 70 to 120 DEG C, and decreasing the drawn yarn feed denier into the crimper by 10 to 60 percent by denier.

Description

Detailed Description of the Invention

FIELD OF THE INVENTION Poly (trimethylene terephthalate) polymers are new polyester resins suitable for use in carpet, textile and other thermoplastics applications. Poly (trimethylene) terephthalate (PTT) is chemically 1,3-
It is an aromatic polyester resin produced by polycondensation of propanediol (PDO) and terephthalic acid. The manufacture of textile staples from PTT is possible on a wide variety of commercial processing equipment.

BACKGROUND OF THE INVENTION PET synthetic fiber staple manufacturing is often separated into two-step processes. The first stage involves the extrusion of undrawn yarn, which is stored for the drawing process in the second stage. Two main types of drawing processes used in staple manufacturing are draw-relax and draw anneal (Dra).
w-Anneal) exists. The fundamental difference between these two processes is how to manage fiber shrinkage. In the production of stretch-relaxed staples, the shrinking strategy is to crimp the fibers to the desired performance and properties and then pre-shrink in an oven. In draw-annealed staple production, the shrinking strategy is to heat the fiber to crimp it for a length before crimping.

Staple fibers have been produced from polyethylene terephthalate (PET) and there are well established methods for doing this. It would be desirable to be able to manufacture PTT staple fibers on existing equipment. However, there are numerous differences between the two polymers that make the production of commercially useful PTT staple fibers in existing staple making equipment difficult or unlikely. In order to understand how to make PTT staples with existing equipment, it is necessary to address several process issues.

How to characterize the drawing behavior of undrawn yarns. Does the drawing behavior of undrawn yarn change to the following over time: As described in Example 1.

How to control the properties of the undrawn yarn during extrusion. As described in Example 2.

What is the typical draw performance for undrawn yarn? As described in Example 3 and Example 4.

How to control fiber shrinkage during undrawn yarn production and storage, as described in Example 5.

How to control fiber shrinkage during staple drawing and in the final staple product. As described in Example 6.

For staple woven spun yarns and nonwovens, how to crimp the fibers to provide surface effects and agglomeration in downstream commercial processes. As described in Example 7.

How to heat set and control the Young's modulus and draw properties of staple fibers. How to influence staple fiber properties to the properties of spun yarn. Example 8
As described in.

What is the basic process for making staples on existing equipment that addresses the interdependent nature of the first six process problems above. Such steps are provided by the present invention.

SUMMARY OF THE INVENTION The present invention describes a two-stage staple manufacturing method using PTT. The first stage is the extrusion of undrawn yarn (UDY). UDY is converted to staple fiber products in the second draw manufacturing stage.

According to the present invention, there is provided a method for producing woven staple fibers from polytrimethylene terephthalate (PTT) in an existing PET woven staple fiber production apparatus, wherein (a) PTT polymer is 245 to 253 ° C., preferably Is from 245 to 250
Melt extruding at ℃, (b) spinning the extruded PTT into a yarn using at least one spinneret, (c) moving the spun yarn to the first winding roll , Where the distance from the spinneret to the first take-up roll is 16 to 20 feet, (d) the spun yarn at 31 ° C. before it reaches the first take-up roll.
Or less, preferably 25 ° C or lower, more preferably 20 ° C or lower, (e
) In some cases, storing the spun yarn in a temperature controlled chamber at a temperature of 31 ° C. or less (both this step and the step before this minimizes premature shrinkage of the undrawn yarn prior to drawing. (F) prior to the drawing process, the yarn is placed under tension, 60
Preconditioning at a temperature above ℃, preferably from 60 to 100 ℃,
(G) drawing the yarn at a temperature of 60 ° C. or higher, preferably 60 to 100 ° C. with any preferred second draw, where most of the total draw, most preferably 80 to 85% of the total draw. Occurring in the first draw, the second and subsequent draws are above the practical maximum temperature of the melting point of the yarn and above the temperature of the first draw, preferably from 60 to 160 ° C.
Most preferably carried out at a temperature of 80 to 100 ° C., (h) in order to achieve an increase in the initial Young's modulus of the drawn yarn, the drawn yarn is below 190 ° C., preferably
Relaxation at a temperature of 0 to 140 ° C. (this relaxation may be 2 to 25% or optionally higher, but is preferably 2 to 10%) and (i)
The drawn yarn is crimped at a temperature of 70 to 120 ° C., preferably 80 to 120 ° C. when the relaxation step is used, and at a temperature of 70 to 100 ° C. when the relaxation step is not used, and the crimping machine Of drawn yarn feed denier from 10 to 6 from the drawn yarn feed rate used to produce comparable PET staples in existing equipment.
There is provided a method comprising the step of reducing by 0 denier percent, preferably 40 to 60 denier percent. Also, alternatively or in combination, the crimper volume can be increased by 10 to 50 percent, preferably 20 to 35 percent, over the crimper volume used to produce PET in existing equipment. it can. Preferably, the choice of conditions is based on the particular equipment and the desired yield.

[0014]     (Brief description of drawings)   The present invention will now be described by means of embodiments with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of the method steps from resin to packaged fiber illustrating its key elements.

FIG. 2 is a strength-elongation balance curve that is useful in assisting in assessing the possible range of staple properties for PTT.

[0017]   FIG. 3 shows a typical stress / strain curve for a spun yarn bundle.

[0018]   FIG. 4 shows the effect of extrusion temperature on fiber drawability.

FIG. 5 shows undrawn yarn shrinkage in water at different temperatures as a function of undrawn yarn spinning conditions.

[0020]   FIG. 6 shows a schematic alignment explaining the effect of fiber shrinkage.

[0021]   FIG. 7 shows the effect of stretching bath temperature and total orientation parameters on boiling shrinkage.

FIG. 8 shows the effect of stretching bath temperature and total orientation parameters on 125 ° C. dry heat shrinkage.

FIG. 9 shows the effect of stretching bath temperature and total orientation parameters on 140 ° C. dry heat shrinkage.

FIG. 10 shows the effect of stretching bath temperature and total orientation parameters on 175 ° C. dry heat shrinkage.

FIG. 11 shows the effect of stretching bath temperature and total orientation parameters on 197 ° C. dry heat shrinkage.

[0026]   FIG. 12 shows the effect of draw ratio and draw bath temperature on draw method relaxation factors.

FIG. 13 shows the expected dry heat shrinkage as a function of dryer (relaxer) oven temperature for free relaxation 1.4 total orientation parameters and 75 ° C. stretching bath temperature.

FIG. 14 shows the effect of relaxor oven temperature and applied yarn stretch on 175 ° C. dry heat shrinkage for 100% PTT yarn.

FIG. 15 shows the effect of relaxor oven temperature and applied yarn stretch on 175 ° C. dry heat shrinkage for 100% PET yarn.

FIG. 16 shows a comparison of PTT and PET spun yarn 175 ° C. dry heat shrinkage at two yarn heat setting temperatures.

FIG. 17 shows the effect of relaxor oven temperature and applied yarn stretch on 175 ° C. dry heat shrinkage for a 50:50 PTT: cotton yarn.

FIG. 18 shows a comparison of PTT and PET spun yarn boiling shrinkage at two heat setting temperatures.

FIG. 19 shows a comparison of loads at 5% strain of PTT and PET spun yarn at two yarn heat setting temperatures.

FIG. 20 shows a comparison of PTT and PET spun yarn 2 minute percent stress relaxation at two spun yarn heat set temperatures.

FIG. 21 shows a comparison of PTT and PET spun yarn percent strain recovery (2 min extension) at two spun yarn heat set temperatures.

DETAILED DESCRIPTION OF THE INVENTION Polymer woven staples can be realized using existing equipment. Since the equipment used by different companies is very different, there will also be differences in the way the method is implemented. When staple makers adapt their settings to the unique properties of PTT, it is possible to produce a wide variety of staple products suitable for use in spun yarns and nonwovens. Woven staples made from PTT provide excellent bulkiness and drape that imparts softness, bulk, compatibility in blends, easy care and shape retention in textile products.

1.0 Polymer Melting 1.1 Resin Transfer and Drying The low energy pneumatic transportation system minimizes dust formation when transferring resin from shipping containers, processing equipment and storage facilities. Prior to extrusion, the PTT resin should be 50
It must be dried to a constant moisture level below ppm. This moisture specification is
Minimize the effect of resin degradation due to hydrolysis during melt spinning. Many types of commercial dryers that use dried air have successfully met this requirement. A dryer equipped with molecular sieves (13X and 4A), a vacuum system and a lithium chloride desiccant met the moisture requirements of commercial products. When possible, it is preferred to dry the polymer using 13X molecular sieves dried air (dew point below -40 ° C) heated to 130 ° C with a drying time of 4 to 6 hours. The use of dry air when moving the dried resin from the dryer to the extruder is essential to minimize hydrolysis during melt spinning.

In a large commercial dryer, P at a rate that can maintain the same rate as the extrusion rate.
The challenge is to dry the TT. In this situation, higher dryer temperatures would be needed. The PTT dryer air temperature should not exceed 165 ° C. 165
When using air at ° C, the drier residence time should not exceed 4 hours.

1.2 Undrawn Yarn (UDY) Extrusion A typical melt production system includes an extruder, spin beam.
m), melt pump and spin pack.
What is important is to establish a uniform and optimum polymer melt viscosity by minimizing melt processing temperature and residence time. Commercial production of PTT UDY by both twin-screw and single-screw extruders is straightforward. In a twin-screw extruder, to avoid excessive shear degradation of the polymer melt,
It may be necessary to reduce the extruder melt pressure by as much as 25 to 50% (from PET conditions). In the commercial manufacture of PTT UDY, extruder melt temperatures in the range of 245 ° C to 270 ° C are used. P at melt temperatures of 260 to 270 ° C
When making TT UDY, care must be taken to avoid excessive degradation of the polymer melt and subsequent UDY properties. The optimum staple extrusion melt temperature for PTT is 245 to 253 ° C, preferably 245 to 250 ° C. Future PTT resins with lower intrinsic viscosities would require lower temperatures. Figure 4 shows the polymer at 250 ° C instead of 240 ° C or 260 ° C.
It shows that a better stretchability can be obtained when extruded.

2.0 Undrawn Yarn (UDY) Spinning 2.1 Spin Beams, Pumps and Packs Attempts to use single component and two component extrusion systems to make PTT staple UDY have been successful. Spin pump volume and rotation control systems sized for PET typically meet the low per position extrusion requirements for PTT staples. The filtration medium should have a minimum pore size of 30 microns. Often, commercial spin packs use a minimum amount of filtration media. P
In the early stages of developing a TT staple manufacturing method, intermediate / coarse sand (90/1
It is preferred to use a standard filtration depth of 20 mesh). An assessment of filament diameter uniformity will help determine whether spin pack filtration or extrusion system melt pressure requires optimization.

The staple extrusion system is designed for specific ranges of resin viscosity, extrusion rate, melt temperature and residence time. Generally, the amount of hole extrusion required to produce PTT staples is usually 2 more than that for PET products of comparable denier.
0 to 30% lower. This necessarily increases the dwell time for the PTT extruded in the PET staple making machine. This increase in melt residence time can lead to decomposition at melt temperatures above 260 ° C. The transfer line and spin beam heating system should, if possible, equal the extruder exit polymer temperature.

2.2 Spinneret The spinneret selection depends on the target product denier and is determined by the limiting extrusion rate per hole-minute for stable melt spinning. In general, PTT staples can use standard PET spinneret designs for similar products. However, PTT staples generally have the following advantages when compared to PET staple manufacturing:
It requires smaller capillary diameters for low denier products. PTT resins have a shear rate upper limit of 7500 to 9000 sec ^-1 for round cross sections depending on melt extrusion conditions.

[0043]   The spinneret selection based on target staple product denier is shown in Table I.

[0044]

[Table 1]

It is important to use a long fiber culmination zone (spinneret to take-up roll distance). This means that this band should be 16 to 20 feet rather than the standard 8 to 12 feet for PET. In the method, the contraction of PTT UDY is relatively high,
The method must then ensure that the fibers establish a stable molecular structure before combining all the filaments into one large draw step feed yarn. PET
In the production of staple fibers this is not a significant issue. PTT has a more elastic crystalline morphology, so that longer fiber finished links help stabilize the yarn, and manufacturing avoids additional air conditioning costs.

2.3 Quenching Trials using the cross-flow and radial quench system were successful. Radial quench systems with air flow from the inside to the outside and from the outside to the inside have been successfully used. U in the spun supply cans
The fiber bundle must be quenched rapidly and uniformly to prevent DY shrinkage. Although quenching temperatures in the range of 8 to 35 ° C are used, temperatures of 8 to 25 ° C are preferred. Generally, the quench air flow velocity is limited by the operability of the UDY yarn passage. The number of filaments per position was 350 to 3500 filaments / position. In fine denier staple manufacturing, it would be possible to have more than 6250 filaments per position in modern radial quench systems. Optimization of the quench system involves determining the conditions that give the best runnability and the highest percent elongation for the target UDY creel properties.

2.4 Spinning Oils All coatings applied to PTT fibers during staple extrusion and stretch manufacturing are defined herein as spinning oils. Spinning oils are fiber coatings that provide lubrication, cohesion and additional protection to PTT fibers during staple manufacture and downstream processing. Both multi-component phosphate and mineral oil based spinning fluids have been successfully used in the manufacture of PTT staples. Proven PET spinning oil chemistries and application methods are satisfactory for early PTT staple products. The spinning oil formulation and application method can then be modified based on consumer feedback on stapling.

2.5 Winding Winding speeds in the range of 900 to 1250 meters / minute were used for commercial PTT UDY production. In the research equipment, the winding speed for UDY is 50
The range was 0 to 2250 meters / minute. Piddle in the Toukens (
Before pendling, the capstan roll is wound up.
It is useful to provide controlled relaxation between the) and the sunflower wheel. In order to minimize UDY shrinkage in the Toukens, it is necessary to cool all filaments to 25-30 ° C or less in a single location.

3.0 Tow Stretching and Finishing 3.1 UDY Storage Under normal storage conditions, PTT UDY completes 90% or more of its aging step within 8 hours of extrusion. The UDY stretch properties stabilized within 24 hours and no significant changes in stretch properties were observed after 2 to 4 months storage at constant temperature. PT
TUDY has the ability to shrink more easily and at lower temperatures than PET UDY. Storage conditions warmer than 25 to 30 ° C. should be avoided as it causes UDY shrinkage. Ideally, the PTT UDY creel is stored in an air conditioned environment to help avoid shrinkage. P
The exact temperature that causes TT UDY shrinkage depends on UDY extrusion, quenching, winding and storage conditions. Even if the PTT UDY shrinks, it is possible to convert this UDY into a first grade commercial staple product during the drawing process with minimal impact on product quality.

3.2 Creel Size The creel size for PTT staples is determined by the size of the production crimper. Generally, the creel size for PTT staples is PTT
Approximately 60% of comparable PET staple products due to higher bulk of fiber
Is. 600,000 denier drawn tow would satisfactorily be supplied to a 110 mm wide by 20 mm high crimper. This will change as the crimper size increases and / or the stretch production rate increases from 100 to over 130 meters / minute. Since most stretch production lines have a maximum line speed of 250 to 300 m / min, increasing the volume of the crimping chamber is another means to improve stretch line productivity.

3.3 Creel and Tow Manufacturing Avoid heating PTT UDY above 25 ° C. until the UDY tow is under uniform roll tension. This will minimize shrinkage of the PTT fed to the drawing process and maintain uniform fiber tension at all points in the tow cross section during drawing. If uncontrolled non-uniform UDY shrinkage is allowed, the can-to-can orientation change will limit the draw process uniformity.

A pre-wetting bath prior to stretching is preferred, but the temperature should not exceed 25 ° C. if no driven and nip rolls are provided to minimize tension into the stretching feed compartment. If no drive rolls are available, the bath should be at the lowest possible uniform temperature.

3.4 Stretching Process PTT staples were manufactured in a stretch relaxation and stretch annealing process arrangement. In the stretch relaxation step, the staples are heat treated and dried under zero tension to reduce shrinkage. This process produces low modulus fibers suitable for PTT spun yarn and for blending with low modulus fibers such as wool and acrylic. The draw anneal step heat treats the tow on rolls under high tension to produce higher modulus fibers that are more suitable for blending with small amounts of rayon, cotton or other higher modulus fibers.

The initial drawing point of the UDY tow in the first drawing stage is at least 60 ° C., preferably 6
It must occur under water heated to 0-100 ° C. Holding the draw point hot improves the draw process performance by significantly reducing the effect of extrusion conditions on the production draw ratio. If desired, the second drawing stage is hotter than the first drawing stage and is below the practical maximum of the melting point of the yarn, preferably 60 to 160 ° C.
, Most preferably 80 to 100 ° C. Unlike PET, PTT will not change to a rough texture in a heated drawing bath. The additional draw zone is optional and usually extends the total mechanical draw ratio slightly. The main draw ratio must be included in the first stage.

PTT on a set of 100-130 ° C. calender rolls with 3% roll relaxation
Annealing or relaxing the staple toe increases the initial modulus of the final PTT staple by 12 to 14%. This process produces high modulus fibers suitable for PTT spun yarn and for blending with high modulus fibers such as cotton, rayon and PET. The initial modulus increases by about 4% from 130-150 ° C to every 10 ° C when the relaxation on the roll set is held at 3%. Annealing the PTT above 150 ° C. requires increasing relaxation on the calender roll to avoid excessive filament breakage. Spinning oils are often applied using a dipping bath or front / back kiss roll application just prior to the crimping step to compensate for spinning oil losses during the drawing process.

3.5 Crimped PTT tow bends very easily compared to PET tow, giving its low bending modulus. This low bending modulus also gives the PTT excellent texture and flexibility. Furthermore, PTT is much more bulky than PET. Low flexural modulus and high bulk require the following modifications in crimp conditions. -Dancer rolls and crimper rolls are reduced to give more control of the crimp shape. • Due to the higher bulk of the PTT, the feed tow denier must be reduced or the crimper volume must be increased. The increased bulkiness of the PTT can be assessed by reducing the amount of toudenier fed to the crimper, most preferably by 10 to 60 percent, preferably by 40 to 60 percent (all in denier). Another means is to increase the crimper volume by 10 to 50 percent, preferably 20 to 35 percent (all by volume). Also, a combination of these two methods can be used. -Ideally, the crimper should be equipped with steam and spinning dosing in order to better control the crimp chamber temperature. -It may also be necessary to improve the accuracy of pressure and temperature control within the crimp chamber.

Crimping stability and winding are significantly improved when the crimper chamber is at least 85 ° C. and a gate pressure of 300 kPa (3 bar). Crimping frequency is higher and crimp height is lower than comparable PET staples. Crimping stability and winding are improved when the crimper temperature is increased. When the crimp stability is increased, the crimper should not be heated too high, as it also increases staple agglomeration, which can increase defects in carding.

3.6 Drying, Cutting and Packaging Relaxation (drying) of PTT staples in a typical belt oven is reliable. However, both crimp shape and shrinkage characteristics change when the oven temperature rises above the hottest temperature in the preceding drawing step. In stretch relaxed staple manufacturing, both staple fibers and subsequent spun dry heat shrinkage decrease as dryer temperature increases.

A relaxation oven is used as a dryer in the manufacture of stretch annealed staples. The air flow rate is relatively high and the air temperature is relatively low (75 to 90 ° C.) to facilitate tow drying. These conditions are not hot enough to allow staple fiber relaxation or crimp shape change. Staple tows were cut in commercial manufacture using a rotary and Pacific converter type cutter without modification. PTT staples were packaged into commercial prototypes by both gravity and pneumatic transport stapler.

4.0 1.7, 2.5 and 3.33 DTEX (1.5, 2.25 and 3DP
F) General Procedures for Staples Draft recipes for three typical staple products are outlined in the table below. All staple manufacturing facilities are different. In order to identify commercial methods for PTT staples, one commercial line is usually made two to three trials. These manufacturing methods were developed on small commercial manufacturing equipment. They are,
When the method is scaled up to larger equipment and higher production rates, it can vary slightly. UDY is manufactured using a melt temperature of 253 ° C. at 1100 m / min. To achieve these draw ratios, uniform extrusion conditions are required such that the filament diameter coefficient of variation is between 3 and 5% at all spinning positions. Furthermore, these draw ratios are obtained with state-of-the-art process equipment which is very well controlled. Achieving only 78 to 85% of these draw ratios is not uncommon for older equipment.

The recipes in Table II also describe the high and low shrink recipes for each target staple denier. The amount of shrinkage during the stretching production is 60 at the first stage stretching bath temperature.
There is a significant decrease as it rises above ° C. Furthermore, the amount of stretch manufacturing shrinkage decreases slightly as the stretch ratio increases. Finally, draw-making shrinkage in the crimper and dryer is further reduced when using calender rolls to anneal the fibers. Commercial product stretch production rates of 100 to 130 meters / min and development stretch rates as high as 225 m / min were used. Commercial stretch relaxation methods typically use 70
A first stretch of 0 ° C and a second stretch of 100 ° C are used. Commercially annealed staple methods typically use 70 ° C. first draw, 100 ° C. second draw and 0.95.
A 130 ° C calender roll at relaxation is used.

[0062]

[Table 2]

4.1 Staple Properties This study of tensile properties assumes that the creel raw material is stretched to within 90% of tow fracture. Typical stretch relaxed PTT staple fibers will typically have a strength of 2.7 to 3.0 cN / dTex and an elongation of between 80 and 90%.
Typical commercial stretch annealed staples have 3.4 to 3.5 cN / dTe.
x and will have an elongation between 60 and 65%. The strength elongation balance curve (FIG. 2) below is useful in helping to assess the possible range of staple properties for PTT. High strength, low elongation PTT staples are very challenging to manufacture due to the rapid relaxation of PTT tow under crimped conditions.
Single filament test results on the R & D equipment show fiber strength as high as 4 cN / Tex at 45% elongation. 3.5 cN / with highly optimized stretch annealing method
PTT staples having a strength greater than Tex can be manufactured. In this effort, control of crimping conditions will be important.

Example 1: Controlling shrinkage of undrawn yarn during extrusion and storage PTT U spun at two different locations under a wide variety of different conditions.
Evaluation of undrawn yarn shrinkage of DY. The test result is 2 to 3% as shown in FIG.
It has been shown that it is best to store PTT UDY below 31 ° C. to avoid larger excess shrinkage. This chart shows several temperatures, -30 ° C
, Percent shrinkage in undrawn yarns immersed in water baths at 31 ° C, 32 ° C and 35 ° C. The spinning conditions were in the range of drawn product denier / filament (dpf) ranging from 0.8 to 4.5 dpf and one at position A and the other at position B, with extrusion rate and winding for different development staple production lines. Covered the operating range of take-up speed The chart also shows that PTT UDY shrinkage is more a function of spinning conditions than quench air temperature. Position A uses 25 ° C. quenching air and position B uses 16 ° C. quenching air. Excessive undrawn yarn shrinkage is undesirable because it can increase staple product variability if not properly controlled.

Example 2: Stapling Process Stretched Stretched PTT Ribbon Shrinking Summary and Conclusion Stretching in a bath above 60 ° C. eliminates all effects of spin-induced structure on as-stretched fiber shrinkage.

Stretched fiber shrinkage decreases with increasing stretching bath temperature, but its effect is 6
It is reasonably small at temperatures above 0 ° C. Shrinkage also decreases with increasing total orientation (draw ratio), but the effect is much less at higher draw bath temperatures. When the draw shrinkage is insensitive to spinning and draw settings, the crimp becomes more stable and the product less volatile. Stretching at temperatures above 60 ° C is recommended and will result in stable crimping operation.

The crimp as a function of dryer / relaxation temperature and the expected relaxation coefficient for drying / relaxation were generated from the shrinkage data. The shape of the curve is correct and can be used for extrapolation of known data, but the coefficient magnitudes appear to be too high.

It seems questionable that product shrinkage as a function of dryer / relaxation temperature can be predicted from shrinkage data for PTT.

Introduction The range of spinning conditions tested in the pilot draw lines used here was as follows:

[0070]   Block temperature of 240 to 260 ° C   -0.432 to 0.865 g / hole-min (0.4 mm capillary)   ・ Spinning speed of 1000 to 2000 m / min   These feeds were drawn at three draw ratios.

Break Stretch Ratio (BODR) minus 0.1 BODR-0.2 BODR-0.4 This, combined with large variations in span orientation, gives a large range of span orientations.

[0072]   Three staple drawing bath temperatures were used.

[0073]   ・ 40 ° C   ・ 55 ℃   ・ 70 ℃   This was the highest practical operating range for the device.

The drawn ribbon was fully characterized. Shrinkage results are analyzed as follows.

Unlike PTT, PET and other melt-spun polymers, where strength and elongation are primarily a function of overall orientation, shrinkage is a more elaborate probe of the fiber structure, and orientation makes it even more important. Especially, it is affected by the crystallinity.

The purpose of this part of the experiment is to answer the following shrinkage problems, presented in their order of importance for method design.

1. Are the differences in spun yarn structure persistent throughout the draw or is the draw process eliminating them? This has important implications in the design of spinning processes and procedures.

2. How does the drawing bath temperature affect shrinkage? Residual shrinkage after drawing is a major factor affecting how easily fibers can be crimped. In general, fibers with high shrinkage are easily crimped. If the shrinkage is a strong function of the drawing bath temperature and orientation, the crimping machine must often be rebalanced, reflecting varying drawing conditions, and the crimps are less uniform.

3. How much shrinkage occurs when a fiber is drawn and crimped, and how is it affected by spinning and drawing conditions? This information is used to calculate the relaxation factor in the spinning model.

4. What additional product shrinkage is present at higher temperatures when the fibers are allowed to relax in the oven at a given temperature.

[0081]   A model that has proven useful for PET has the following assumptions.

When heated above the glass transition temperature, unless suppressed, the fibers will shrink until all amorphous regions have been deoriented.

When the temperature rises above the glass transition temperature, the additional oriented amorphous regions become
Appears as a crystalline melt. These newly created amorphous regions are then deoriented to provide additional shrinkage. Therefore, generally, the higher the temperature, the higher the contraction.

Some definitions, which are somewhat roundabout in nature, are now needed. The glass transition temperature is defined as the temperature at which unrestrained amorphous chains are free to deorient as required by the second law of thermodynamics. The amorphous region is not crystalline. The crystalline regions are those that do not deorient at this temperature. The crystalline region is T
There are numerous means to define in terms of GA curves, X-ray behavior, density, etc., all giving somewhat different but related answers in terms of% crystallinity. For the purposes of this discussion, we define crystals in terms of their ability to retain their orientation at temperature.

The assumption that heat treating the rope only results in crystalline melting and fiber deorientation is unique in this model. This model works well for PET yarns that have been relaxed in the process with short residence times. This works well for staple processing involving dwell times of a few minutes, but its effectiveness for PTT was not known prior to the present invention.

The length, orientation diagram in FIG. 6 can be used to illustrate this process. This diagram, fibers, sample fiber length from the length at zero birefringence represents what happens when stretched to l _f. When heating this fiber to a temperature T ₁ ,
All amorphous regions are deoriented, all crystals that are not stable to T ₁ melt,
Since it also deorients, it loses length up to l ₁ .

The fibers are not completely deoriented, as there are still crystals that are stable at T ₁ . When the temperature rises to T _2, additional crystals melt, become amorphous, and disorientation, and is further reduced length. Although it would seem possible to completely shrink to a zero birefringence stretch ratio of 1.0, in practice there are some crystals that are stable up to and above the melting point (which It causes problems in PET polymerization). These do not deorient, so the reorientation can never be completed.

It is possible to tackle experimental problems by the following introductions following the inventors. Do differences in spun yarn structure persist through drawing?

It is expected that shrinkage should be a strong function of draw ratio, as shrinkage is what gives the orientation that is lost. In PET this is true to some extent, but this effect is totally overshadowed by the fact that there is an effect of resisting the increased orientation as the orientation increases and the ability to form crystalline regions increases. Fades. Also in PET, at elevated drawing bath temperatures, all memory of spinning is erased as long as shrinkage is concerned. Orientation can be approximated as a total orientation parameter (TOP) (denier stretch ratio / specific stretch ratio).

In order to calculate the intrinsic stretch ratio, it is necessary to determine the appropriate strain rate for laboratory equipment and techniques that give reproducible results. Single tubes spun at 40 # / hr, 240 ° C. and 1500 m / min were tested at strain rates of 200 to 800% / min. Three replicate measurements were performed with the curve plotted on one graph. The results were highly reproducible at all strain rates, indicating good laboratory technology and equipment. All determinations gave the characteristic curve shown in FIG. The intrinsic stretch ratio can be easily calculated from these plots as follows.

NDR = 1 + (S _n / 100) (1) (where S _n is the strain% at the intrinsic stretching strain) This is: NDR = l _d / l _s (2) (where l _d is the length at the intrinsic stretch inflection point and l _s is the length of the spun sample) The first step is which variables are statistical in predicting shrinkage at a given temperature. Is to establish what is significant to. The procedure was to use a stepwise anterior and stepwise posterior regression procedure with Sigma Stat 2.0 with F> 4.0 for acceptance and P <0.05 for rejection. .

[0092]   The results summarized in Table III show that:

[0093]   -Both measures were generally the same.

• At draw temperatures above 60 ° C, spinning variables do not play a significant role in drawn fiber shrinkage.

• All orientation parameters and, surprisingly, block temperature were a slightly significant factor in shrinkage at a draw temperature of 45 ° C.

It is concluded that a draw temperature of 60 ° C. or higher should be used to eliminate any spinning effect on product shrinkage. This data, like PET, supports the hypothesis that using a drawing temperature significantly higher than Tg clears the spinning structure. The regression equation for correlation with r ² > 0.5 is reported in the table below. T
Note that this is not the case for> = 60 ° C.

[0097]

[Table 3]

How does the drawing bath temperature affect shrinkage? FIGS. 7 to 11 are plots of Boil Off Shrinkage and dry heat shrinkage at 125 ° C., 140 ° C., 175 ° C. and 197 ° C. for the three draw bath temperatures used. It is clear that there is a large mechanical change between 45 ° C. and the next higher temperature tested, 60 ° C. At temperatures above 60 ° C., shrinkage is largely independent of orientation and relatively insensitive to bath temperature.

At higher bath temperatures, the shrinkage capacity is reduced by a small amount, but not in terms of crimping capacity or perhaps product performance.

Operation at temperatures above 60 ° C. is recommended as the crimper operation is greatly simplified. Crimper adjustment under these conditions is not necessary except to correct the denier density to the crimper (denier / linear crimp inch, dtex / linear crimp cm).

How does spinning and drawing bath temperature affect the relaxation coefficient? Figures 7 to 11 and analysis of the variables show that, except for the lowest temperature tested, 45 ° C, the shrinkage capacity of the drawn rope is independent of spinning conditions and only slightly dependent on orientation. There is.

FIG. 12 shows the relationship between oven temperature and relaxation coefficient for drawn ropes. At stretching bath temperatures above 60 ° C., the straight line passing through the group above the data points will approximate the relaxation coefficient. This is a good starting point, but this shrinking method uses a small weight of sample so it is not completely free to relax as it is in a typical plant dryer / relaxer So the value will be too high (shrinkage too low).

However, the curve has the correct shape, so when more machine-specific data is obtained, it will be good enough to extrapolate temperature effects.

[0104]   Can relaxed product shrinkage be predicted from ribbon shrinkage data?

[0105] With reference to simple shrinkage model for 3 and PET, if you put the fibers of l _f in an oven at T _1, it will lose amorphous orientation and some melts and disorientation of the crystal , Its length will decrease to length l ₁ . Similarly, when a sample of length l _f is placed in an oven with T ₂ higher than T ₁ , it shrinks more as more of the crystalline material melts at the higher temperature, and length l _f Will shrink to ₂ .

[0106]   Mathematically, shrinkage can be represented by the following method.

[0107] the percent shrinkage at _{Φ 1 = T 1/100 (} 1) Φ 2 = percent shrinkage at _{T 2/100 (2).}

[0108] Then, dry heat from the definition of shrinkage _{Φ 1 = (l f -l 1} ) / l f = 1-l 1 / l f (3) Φ 2 = 1-l 2 / l f (4) T 1 What does it do with shrinkage at T ₂ when testing a sample relaxed freely at? If no crystalline growth or changes other than melting and deorientation occur during the first shrinking step, it will shrink to l ₂ .

The first shrinkage is then what the fiber experiences in the relaxor and the second shrinkage is the residual shrinkage in the relaxed product. To some extent PET is able to follow these assumptions, so it is possible to deduce the relaxed product shrinkage from the dry heat shrinkage of drawn ribbons.

What must be calculated to do this is that the product shrunk at T ₁ is
A contraction that is contracted a second time at T ₂ . This can be done by using the contraction definition and FIG. 3 as follows.

Φ _ps = (% shrinkage of sample shrunk at T ₁ when shrunk at T ₂ ) / 100
(5) Φ _ps = (l ₁ −l ₂ ) / l ₁ = 1−l ₂ / l ₁ (6) Estimate l ₁ and l ₂ in terms of dry heat shrinkage measured at two different temperatures. Using Equations 3 and 4 to do this,

Φ _ps = 1− (1−Φ ₂ ) / (1−Φ ₁ ) (7) From this and the measured shrinkage, the expected product shrinkage at T ₂ after oven relaxation at T ₁ is calculated. Can be calculated.

FIG. 13 is a plot of expected shrinkage for technically useful cases of high orientation and high bath temperature. It is clear that the expected fiber shrinkage after a given oven relaxation is too low. This indicates that in addition to simple deorientation, significant crystallinity changes occur in the dryer / relaxation.

Example 3: Evaluation of PTT staple fiber heat setting on properties of PTT spun yarn properties under heated strain conditions: evaluated yarns include PTT, PTT / PET blends, PTT / cotton blends And PET are included (Table IV) Filament breakage during extrusion of PTT synthetic fibers severely limits product productivity and product quality. PTT resins having an IV within the range of 0.55 to 1.0 are preferred, those having an IV range of 0.675 to 0.92 are more preferred, and
Most preferred are those having an IV range of 72 to 0.82. 0.72 to 0.8
Producing PTT synthetic fibers with an intrinsic viscosity range of 2 helps improve synthetic fiber production runnability and product quality without a significant reduction in final fiber properties.

[0115]   Reducing the intrinsic viscosity of PTT helps:

1. It reduces the amount of change in the viscosity of the tip as compared to the viscosity of the extruded fiber.

2. Improve the homogeneity of the polymer melt in the spin pack. PTT resin with an IV of 0.92 requires a more stringent spin pack filtration system to maintain marginal yield in extrusion.

3. Improves manufacturability by reducing the number of broken filaments during manufacture.

For extruded filaments having a denier / filament of less than 4.2, it is possible to run the product at lower extrusion temperatures. PTT is 26
It is known to decompose at melt extrusion temperatures above 0 ° C. When producing fine denier synthetic filaments (filaments with dpf less than 2) using 0.92IV resin, avoiding excessive melt stream turbulence and melt decomposition, which breaks the filaments during extrusion. In order to sufficiently reduce the melt viscosity, the melt extrusion temperature must be increased.

5. The amount of shrinkage in the product fibers is reduced to facilitate the drawing process and / or wrapping into a staple yarn package.

Staple yarns made from PTT are surprisingly elastic and have 1% of the original yarn length.
It has recoverable elasticity when stretched from 5 to 25% or less. This elasticity is also present in staple yarns made from tight and non-tight fiber blends in which PTT is the main fiber component on a weight and / or length basis. Moreover, this elasticity is recoverable after hundreds of cycles. This elasticity is sufficient to enhance the shape retention properties of woven fabrics made from PTT staple yarns and blended staple yarns. Properly constructed and finished, most PTT staple spun yarn containing fabrics (by weight percent length) can have surprisingly high elastic recovery in woven and knitted fabrics (500 by hand). 200 cycles or more and depending on equipment
Cycle tested). The present invention covers the formation of staple spun yarn by conversion of staples into a twisted yarn structure by all methods. Spun yarn can be produced by hand, spinning wheel, ring spinning, open end spinning, air jet spinning or other types of staple to yarn conversion equipment.

Staple yarns made from cotton, wool, acrylic, PET are not elastic. In order to produce staple yarns that are elastic from these fibers, it is common in the industry to add elastic continuous filaments internally to the yarn or cloth to impart elastic properties to the final textile product. I won't. These solutions are more expensive than the basic staple spun yarn made from PTT. The value of the present invention is that people with basic staple spun yarn technology either invest in more expensive core spun yarn equipment or include elastic continuous filaments in the fabric structure, which in turn It is possible to produce elastic spun yarns of commercial value without complicating the dyeing and finishing process.

Staple fiber heat setting properties of PTT staple and PTT blended with cotton
Efforts have been made to briefly characterize how the behavior of yarns made from PTT staples blended with staples and PET staples is affected. As described in Table IV, PET and cotton blend yarns were made at different relaxor temperatures and made from several PTT staple feeds with significantly different crimps. So the effect of blending with other fibers cannot be clearly identified. Therefore, care must be taken in inferring the exact blend level effect from these experiments. This experiment examines each of the example yarns in terms of shrinkage, modulus, stress relaxation and recovery. These factors are generally independent and were studied separately in this work.

[0124]

[Table 4]

Summary and Conclusions On Spun Yarn 175 ° C. Dry Heat Shrinkage: Spun yarn dry heat shrinkage was measured for all blends tested (100% PTT, 100%).
PET, 50/50 PTT / PET and 50/50 PTT / cotton) decreased with oven temperature.

Dry heat shrinkage increases by approximately 1/2% for each% of stretch (or relaxation) applied for all blends tested.

[0127]   • PTT spun yarn shrinkage was 2 to 2 + 1/2% less than PET yarn.

[0128]   • The PTT data closely followed the amorphous deorientation model for shrinkage.

• On Spun Yarn Boil Shrinkage • Boil shrinkage decreased with oven temperature for all blends tested.

• Boil shrinkage increases by about 0.4% for each 1% of stretch applied for all blends tested.

The PTT spun yarn was about 1% smaller in boiling shrinkage than the PET yarn because the PTT was produced by the stretch relaxation method, while the PET sample was stretch annealed.

On Spun Yarn Load at 5% Strain (Extension): A fabric is perceived as “stretchable” when it requires very little force to change its length by a significant amount. In this setting of trials, we choose to characterize the stretch by observing the force required to strain the fabric by 5%. The main variable affecting all blends tested was the stretch applied. Oven temperature is not very important and this rating shows that:

• PTT showed 3-4 times less force than PET to stretch 5% (greater stretch).

The amount of stretch of PTT decreases with the stretch applied, being 1/10 of that of PET
(0.01 gpd increase / 1% stretch vs. 0.1). So the applied stretch is
It can be used with PTT to modify yarn properties without large yarn extension penalties.

[0135]   The elongation of 100% PTT yarn was relatively insensitive to heat setting conditions.

Spun Yarn Stress Relaxation How much the yarn or fabric recovers after being subjected to a given strain for a given length of time depends on two requirements:

[0137]   1. How much stress relaxation occurs while strain is maintained.

[0138]   2. The amount of recovery after the stress is released.

[0139]   These factors are generally independent and were studied separately in this work.

PTT stress relaxation was independent of heat setting temperature and decreased linearly with increasing applied elongation (0.5% decrease in stress relaxation / 1% applied elongation in heat setting) ).

-PET stress relaxation decreased linearly with increasing oven temperature and with increasing applied stretch. The stretch effect applied is significantly stronger than PTT (-0.9% /% stretch applied).

[0142]   -PTT and PET showed roughly the same amount of stress relaxation.

• The PTT / PET blend yarn behaved approximately half way between the corresponding pure yarns with -0.7% reduction /% elongation applied.

[0144]   • PTT / cotton blend yarn stress relaxation is independent of heat setting temperature.

Spun Yarn Recovery The recovery for PTT yarns from this sample set was much smaller than that observed for the recently tested pre-marketed yarn samples with 98% recovery.
The cause for this would be the 100 ° C dryer oven used in the fiber treatment.
The major heat setting variable affecting recovery for all samples tested was applied stretch, with increasing stretch applied and recovery increasing.

[0146]   -PTT recovery increases with stretch applied 0.9% / 1%.

[0147]   -PTT generally had a recovery of 5-10% higher than PET.

The PTT / cotton blend data was very unstable but showed the same general trend as the pure yarn.

Shrinkage Principle In a semi-crystalline polymer fiber with a pronounced orientation, the orientation lies in two regions, a crystalline region and an amorphous region connected to the crystalline range. Usually, there is a range of crystal sizes and the orientation of crystalline regions can change.

When the fibers are exposed to temperatures below the glass transition temperature, the length change is very slow and is called creep. Generally, all useful textile fibers have a low creep rate in the absence of load. When the fibers are heated above the Tg, the amorphous regions become mobile and, in the absence of restraining forces, deorientate closer so that they are in the isotropic state (not the preferred orientation). The isotropic state is treated by the second law of thermodynamics. This usually results in shrinkage, but in the rare case the crystalline region collapses on itself,
There is a "negative" orientation in which the fibers grow. Such fibers are called self-stretching. This is not known if they can be manufactured from PTT.
The crystalline region is not mobile and does not deorient.

As the temperature of the fiber continues to rise, the smaller crystals melt and their range becomes amorphous. Here, they deorient and additional shrinkage occurs. This is why, for semi-crystalline polymers, shrinkage generally increases with increasing temperature. Thus, there are two strategies for reducing fiber shrinkage:

[0152]   1. Pre-shrink the fiber to the temperature at which it is desired to be stable.

2. The fibers are allowed to crystallize under heat and tension at a temperature at which they do not want to shrink and at a temperature at which they stabilize the crystals.

For commercial PET fibers, if the problem is spinning and weaving efficiency and yarn strength, the second route is exclusive because preshrinkage reduces the fiber modulus, as we will see later. Is used for. For specialty fibers, especially wool blends, the first route is used because strength and modulus are not important issues, but the better dyeability afforded by route 1 is an advantage. At this time, PT
It is not clear which is the better route for T.

When a fiber is stretched, its amorphous orientation increases, thus causing shrinkage. PET
In non-twisted continuous filament yarns, there is often a one-to-one correspondence (5% stretch increases shrinkage by 5%).

So far, the inventors have investigated single uncrimped fibers. The situation for spun yarns is more complicated for the following reasons.

• The fibers are twisted at a helix angle, which reduces the effect of fiber shrinkage on the yarn.

[0158]   -The fibers move from the outside to the center of the yarn.

[0159]   The fibers can slip in the yarn.

• The presence of blended fibers with different shrinkage can change the shrinkage of the assembly.

Despite these complications, we can use a simple model to predict the response of spun yarn to heat setting conditions.

1. If the yarn is heated and allowed to relax, it will deorient and the crystallinity will increase. Both factors reduce contraction. At constant oven temperature, shrinkage reduction will be linear with relaxation. Shrinkage will decrease with increasing oven temperature.

2. When the yarn is heated and held at a constant length, there is no deorientation. Contraction is
As long as the yarn processing oven temperature is higher than that experienced by the fibers during the free-making and relaxation steps in fiber production, it decreases with increasing oven temperature.

3. If the yarn is heated and stretched, the orientation will increase and it will contract. Shrinkage increases linearly with applied elongation and decreases with increasing oven temperature as long as the oven temperature is higher than that seen during fiber processing.

Properly based on this, we are ready to analyze the effect of heat setting conditions on yarn shrinkage.

175 ° C. Spun Yarn Dry Heat Shrink As shown in FIG. 14, PTT is an excellent support that follows all the rules of the full orientation model.

The control relaxed at 100 ° C. with 0% applied stretch has exactly the same shrinkage as the yarn treated at 100 ° C. When treated at higher temperatures, shrinkage is still reduced for a given length.

When the length varies with applied stretch or contraction, the contraction increases linearly with applied stretch and the slope is nearly constant with oven temperature. At a given oven temperature of 176 ° C, dry heat shrinkage is increased by about 0.46% per 1% applied stretch.

PET behaves in a similar fashion, FIG. Since this is annealed fiber, not relaxed fiber, the shrinkage of the control yarn decreases with increasing oven temperature even at 100 ° C. Since this is a high modulus, at high stretch and low oven temperature the fiber does not stretch but slips in the yarn and the increase in shrinkage is not as great as for PTT. For oven temperatures above 130 ° C PET
Dry heat shrinkage is increased by about 0.55% per 1% applied stretch. This is somewhat higher than PTT, but a good rule of thumb for both is a 1/2% shrinkage increase for 1% stretch.

FIG. 16 compares PTT and PET yarn shrinkage for the highest and lowest heat setting temperatures. PTT is about 2 to 21/2% more than PET for equivalent oven conditions
Has low dry heat shrinkage. As noted above, both have approximately the same increase in contraction with applied stretch.

The PTT / cotton blend is similar to the PET blend (FIG. 17) with shrinkage increasing with decreasing oven temperature and increasing with applied stretch. The increase with applied stretch is clearly linear with shrinkage being approximately 0.47 per 1% stretch applied.
%To increase. The shrinkage of the cotton blend is about 1% less than the PET blend for similar conditions. For this sample set, a good rule of thumb is that 1% applied stretch increases the dry heat shrinkage by 1/2%.

Boiled Shrinkage Boiled shrinkage is the same as dry heat except that the available amorphous orientations are all crystals present in the fiber plus the glass transition and 100 ° C. melting. Behaves in a manner so that it is much lower than dry heat shrinkage. This shrinkage can be significant in some fibers where the plasticizing effect of water is high. Fibers produced by the stretch relaxation method at relaxation temperatures above 100 ° C generally have very low boiling shrinkage. Annealed fibers generally have a relatively high boiling shrinkage because they are heated under tension and there is always an amorphous orientation.

These samples generally follow these principles. All blends are
It behaves in a manner similar to dry heat shrinkage, where shrinkage decreases with increasing oven temperature,
Increases with applied stretch.

[0174] The PTT control yarns have the following properties:
It had a shrinkage of 2%. This indicates that some cold stretching occurred during processing, probably during carding. This is unexpected and gives a low PTT modulus. PTT yarn shrinkage increased by about 0.38% per 1% applied stretch. The control PET yarn had significantly higher shrinkage (4.5 vs. 2%) than PTT, as it was made by the annealing method. Yarn shrinkage increased about 0.47% per 1% applied stretch. Generally, PTT yarns have a dry heat shrinkage that is almost 1% lower than PET yarns, giving similar yarn heat setting conditions (FIG. 18).

The PTT / PET blend yarn had a shrinkage increase of 0.44% per 1% applied stretch and the PTT / cotton yarn had an increase of 0.417. A good rule of thumb for boiling shrinkage is that for all conditions tested, it increases by about 0.4% per 1% applied stretch.

For 100% PTT spun yarn, the load at 5% strain is almost independent of oven temperature and is linearly related to the applied stretch and 1% at the applied stretch.
About 0.01 gpd increase per increase. This means that the yarn stretch is reduced when the yarn is drawn during heat setting. Note for the PTT data that the control yarn made from 100100% relaxed fiber has essentially the same 5% strain load as 0 stretch and heat set at 100 ° C.

PET yarn behaved in a similar manner. In this case, there was a significant change for the control yarn versus the yarn heat set at 100 ° C. and 0 applied stretch, as the feed fiber was annealed and not relaxed. PET load at 5% elongation is P at applied elongation
An order of magnitude higher than TT, an increase of 0.1 gpd per 1% applied stretch.

FIG. 19 compares the behavior of PTT and PET and the stretching advantage of PTT is clearly evident. For 5% strain, with no stretch applied, the force not only required a lower coefficient of 3, but the response to the stretch applied was also very low, which means that the applied stretch is over-priced to the yarn stretch. It means that it can be used for heat setting of PTT yarn without paying. Interestingly, the best applied stretch PTT
Item (7.5%) is 45% at 5% strain compared to the 7.5% relaxed PET sample.
% Requires low power.

Spun Yarn Stress Relaxation How much the strain in the yarn or cloth recovers after being strained and held at a constant length for a certain time depends on the following two factors.

How much stress relaxation occurs while holding the sample at a constant length. In the extreme case, if all the stress is lost, the recovery will be zero.

[0181]   How well will the strain recover after the test time?

This spun yarn stress relaxation experiment involved straining the yarn by 5%, then holding the spun yarn at a length for 2 minutes and allowing the yarn to recover to zero stress. The stress relaxation is somewhat less accurate than the values calculated manually from the test chart and machine-calculated from the computer analysis method. Stress relaxation and recovery are two different phenomena and will be considered separately.

The stress relaxation of 100% PTT yarn is independent of oven temperature and decreases linearly with applied stretch. Intuitively, it is believed that stress relaxation will increase with applied stretch, but r ² for this relationship is very high. PTT stress relaxation is reduced by about 0.5% per% stretch applied. Although there is a definite oven temperature effect, PET yarn behaves in a similar manner and the reduction per applied stretch unit (0.9% relaxed / 1% applied stretch) is almost double that of PTT. . FIG. 20 compares PTT stress relaxation with PET stress relaxation. Generally PET
Is higher at low applied stretch and lower than PTT at high oven temperature and applied stretch. The behavior of the PTT / PET blend is half that between two pure fibers, lower oven temperature sensitivity, and a 0.7% reduction in stress relaxation per 1% applied stretch. Stress relaxation for PTT / cotton blends was independent of heat setting temperature.

Spun Yarn Recovery PTT recovery was unaffected by oven temperature and increased linearly with increasing applied stretch (0.9% recovery / 1% applied stretch). PET recovery increased slightly with increasing oven temperature, but the main effect was applied stretch. The response is much more pronounced than for PTT, an increase of 2.2% recovery for each 1% applied stretch. As shown in FIG. 21, the PTT generally has the exception that the PET had a high level of extension applied in a high temperature oven.
It has a recovery of 5 to 10% higher than PET. The PTT / PET blend yarns were not oven temperature dependent and had a strong response to applied stretch (an increase in 1.7% recovery for each 1% applied stretch), similar to pure PTT. did.
The PTT / cotton blend results were unstable at higher oven temperatures and higher applied stretch, which increased recovery.

Characteristic Offsets in Spun Yarn Heat Set One of the main reasons for doing this work is: "How much the elongation, recovery and stress relaxation decreases when the yarn is heat set to reduce its shrinkage. Do you want to do that? ". In order to answer this question for this data set, it is necessary to plot these variables against each other. Since all variables are independent variables, this relationship holds true only for this data set and other sets that have changed the independent variables in the same manner as we did here. Pay attention to this and observe the response.

[0186]   About the stretch / dry heat shrinkage offset, the stretch (load at 5% strain reduction)
It increases when it decreases. By reducing the shrinkage by shrinking the thread
This is an advantageous deal as there is no extension penalty to pay. r ^Two Is very low at 0.47, but considering that all points are included, this
The data are probably a reliable trend guide. Load at 5% is due to shrinkage
0.01 gpd decrease for each 1% decrease.

Recovery / dry heat shrinkage cancellation is not advantageous. Recovery is reduced by 1.3% for each 1% decrease in dry heat shrinkage. The r ² for this data is significant and is 0.
It was 64.

The stress relaxation / dry heat shrinkage offset is not favorable, increasing the stress relaxation by 0.9% for each 1% applied stretch in dry heat shrinkage. This increase in stress relaxation is believed to be responsible for the decrease in recovery. In any case, dry heat shrinkage should be reduced to the minimum amount required by the end user.

Example 4: Reducing Resin IV of Resin PTT from 0.92 to 0.82 provides improved extrusion reliability in PTT staple manufacturing.

Filament breakage during extrusion of PTT synthetic fibers severely limits productivity and product quality. Producing PTT synthetic fibers with an intrinsic viscosity range of 0.72 to 0.82 helps improve synthetic fiber production runnability and product quality without a significant reduction in final fiber properties.

Reducing the intrinsic viscosity of PTT is compared to the viscosity of extruded fibers by
Helps reduce the amount of change in chip viscosity. It also improves the homogeneity of the polymer melt in the spin pack. PTT resin with an IV of 0.92 requires a more stringent spin pack filtration system to maintain marginal yield in extrusion. It also improves manufacturing runnability by reducing the number of broken filaments during manufacturing. This allows the product to run at lower extrusion temperatures due to extruded filaments having denier / filament less than 2. PTT is known to decompose at melt extrusion temperatures above 260 ° C. When making fine denier synthetic filaments (filaments having dpf less than 2) using 0.92 IV resin, excessive melt flow turbulence and melt decomposition resulting in filament breakage during extrusion. The melt extrusion temperature must be increased in order to reduce the melt viscosity sufficiently to avoid. This also reduces the amount of shrinkage in the product fiber,
Facilitates the drawing process and / or winding into a staple yarn package.

[Brief description of drawings]

  The present invention will now be described by means of embodiments with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of method steps from resin to packaged fiber illustrating its key elements.

FIG. 2 is a strength-elongation balance curve useful in aiding in assessing the possible range of staple properties for PTT.

[Figure 3]   3 shows a typical stress / strain curve for a spun yarn bundle.

[Figure 4]   The effect of extrusion temperature on fiber drawability is shown.

FIG. 5 shows undrawn yarn shrinkage in water at different temperatures as a function of undrawn yarn spinning conditions.

[Figure 6]   An orientation outline explaining the influence of fiber shrinkage is shown.

[Figure 7]   The influence of the drawing bath temperature and all orientation parameters on the boiling shrinkage is shown.

[Figure 8]   3 shows the influence of stretching bath temperature and total orientation parameters on 125 ° C. dry heat shrinkage.

[Figure 9]   3 shows the effect of drawing bath temperature and total orientation parameters on 140 ° C. dry heat shrinkage.

[Figure 10]   Figure 3 shows the effect of drawing bath temperature and total orientation parameters on 175 ° C dry heat shrinkage.

FIG. 11   3 shows the effect of stretching bath temperature and total orientation parameters on 197 ° C. dry heat shrinkage.

[Fig. 12]   The influence of the stretching ratio and the stretching bath temperature on the relaxation coefficient of the stretching method is shown.

FIG. 13: Free relaxation 1.4 For all orientation parameters and 75 ° C. stretching bath temperature, dryer (
(Relaxer) shows the expected dry heat shrinkage as a function of oven temperature.

FIG. 14 shows the effect of relaxor oven temperature and applied yarn stretch on 175 ° C. dry heat shrinkage for 100% PTT yarn.

FIG. 15 shows the effect of relaxor oven temperature and applied yarn stretch on 175 ° C. dry heat shrinkage for 100% PET yarn.

FIG. 16 shows a comparison of PTT and PET spun yarn 175 ° C. dry heat shrinkage at two yarn heat setting temperatures.

FIG. 17 shows the effect of relaxor oven temperature and applied yarn stretch on 175 ° C. dry heat shrinkage for a 50:50 PTT: cotton yarn.

FIG. 18   Figure 3 shows a comparison of boiling boiling shrinkage of PTT and PET spun yarn at two heat setting temperatures.

FIG. 19 shows a comparison of loads at 5% strain PTT and PET spun yarn at two yarn heat setting temperatures.

FIG. 20 shows a comparison of PTT and PET spun yarn 2 minute percent stress relaxation at two spun yarn heat set temperatures.

FIG. 21: PTT and PET spun yarn percent strain recovery at two spun yarn heat set temperatures (
2 minutes extension) is shown.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE, TR), OA (BF , BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, G M, KE, LS, MW, MZ, SD, SL, SZ, TZ , UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, B Z, CA, CH, CN, CR, CU, CZ, DE, DK , DM, DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, J P, KE, KG, KP, KR, KZ, LC, LK, LR , LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, R O, RU, SD, SE, SG, SI, SK, SL, TJ , TM, TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Inventor Dangayak, Kailas             United States, Texas77079, Burrow             Uston, Windbreak Trail             755 (72) Inventor Oliveri and Linda Harvey             Kay, Texas 77450, United States             Tay, Lanham Drive 23042 (72) Inventor Schiffler, Donald Albert             United States, North Carolina             28504, Kinston, Hardy Road             1700 F-term (reference) 4L035 BB55 BB87 BB89 BB96 EE01                 4L036 MA05 MA33 PA01 PA03 PA28                       PA36 RA04 UA07                 4L048 AA22 AA33 AA43 AA47 AA50                       AA55 AB01 AC11 AC12 CA03                       CA04 DA02 DA03

Claims (10)

[Claims] 1. A method for producing woven staple fibers from polytrimethylene terephthalate (PTT) in an existing PET woven staple fiber production apparatus, comprising: (a) melt extruding a PTT polymer at 245 to 253 ° C. A step of: (b) spinning the extruded PTT into a yarn using at least one spinneret; (c) moving the spun yarn toward a first winding roll, where: The distance from the spinneret to the first take-up roll is 16 to 20 feet. (D) cooling the spun yarn to a temperature below 31 ° C. before it reaches the first take-up roll, (e) ) Optionally storing the spun yarn at a temperature below 31 ° C., (f) pre-conditioning the yarn under tension at a temperature above 60 ° C. before stretching, (g) 60 ℃ or more Drawing at a temperature, (h) optionally relaxing the drawn yarn at a temperature of 190 ° C. or lower, and (i) crimping the drawn yarn at a temperature of 70 to 120 ° C. and drawing yarn feed rate From the drawn yarn feed rate used to produce comparable PET by 10 to 60 denier percent. 2. The method according to claim 1, wherein the intrinsic viscosity of PTT is 0.55 to 1.0. 3. The intrinsic viscosity of PTT is 0.72 to 0.82.
The method described. 4. The method according to claim 1, 2 or 3, wherein the spun yarn is cooled to below 25 ° C. before it reaches the first winding roll. 5. The crimping temperature is 70 to 100 ° C. without using a relaxation step.
The method of claim 1. 6. The method according to claim 1, wherein a relaxation step is used and the crimping temperature is 80 to 120 ° C. 7. Step (i) further includes using a crimper volume that is 10 to 50 percent greater than the crimper volume of the crimper used to produce comparable PET. 7. The method according to any one of claims 1-6. 8. The method of claim 1, wherein the drawn yarn feed rate is reduced by 40 to 60 percent. 9. A method for producing woven staple fibers from polytrimethylene terephthalate (PTT) in an existing PET woven staple fiber production apparatus, comprising: (a) melt extruding a PTT polymer at 245 to 253 ° C. A step of: (b) spinning the extruded PTT into a yarn using at least one spinneret; (c) moving the spun yarn toward a first winding roll, where: The distance from the spinneret to the first take-up roll is 16 to 20 feet. (D) cooling the spun yarn to a temperature below 31 ° C. before it reaches the first take-up roll, (e) ) Optionally storing the spun yarn at a temperature below 31 ° C., (f) pre-conditioning the yarn under tension at a temperature above 60 ° C. before stretching, (g) 60 ℃ or more Drawing at a temperature, (h) optionally relaxing the drawn yarn at a temperature of 190 ° C. or less, and (i) at a temperature of 70 to 120 ° C. to produce a comparable PET. A method comprising crimping using a crimp volume which is 10 to 50 percent greater than the crimp volume of the crimper used. 10. Step (g) includes at least two stretches, 60 for the first.
10. A method according to any one of claims 1 to 9, wherein the method is carried out at a temperature above C and the second and, if present, subsequent drawing is carried out at a temperature above the melting point of the yarn and above the first.