KR20020091131A - Poly(trimethylene) terephthalate textile staple production - 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

TECHNICAL FIELD [0001] The present invention relates to a method for producing a staple of poly (trimethylene) terephthalate fabric,

PET synthetic fiber staple production is often split into a two-step process. The first step involves the extrusion of a non-drawn yarn stored for draw processing in the second step. There are two main types of draw processes used in staple production: Draw-Relax and Draw-Anneal. The fundamental difference between these two processes is how fiber shrinkage is addressed. Draw relaxation The strategy of shrinkage in staple production is to pre-contract the fibers in the oven after crimping to the desired performance and properties. Drawing Annealing In staple production, the shrinkage strategy is to heat the fibers to allow a certain length of crystallization before crimping.

Staple fibers have been produced from polyethylene terephthalate (PET) and such methods have been well established. It is desirable to be able to produce PTT staple fibers in existing devices. However, there are a number of differences between the two polymers that make it difficult or unlikely to produce industrially useful PTT staple fibers in existing staple production machines. In order to understand how to produce PTT staples in existing devices, it is necessary to handle several process questions:

How do you characterize the draw-action of a non-drawing yada? Non-Drawing How does the draw function in the night change over time? As described in Example 1.

How do we control the properties of the non-drawing yada during extrusion? As described in Example 2.

What are the usual draw practices for non-drawing yards? As described in Examples 3 and 4.

How do you control fiber shrinkage during non-drawing yard production and storage? As described in Example 5.

How do you control fiber shrinkage during staple draw and in final staple products? As described in Example 6.

Staple fiber spinning How to crimp fiber to provide texture and bonding in downstream industrial processes for yarns and nonwovens? As described in Example 7.

How do you heat set and adjust the young's modulus and stretch properties of staple fibers? How does the nature of the staple fiber affect the properties of the spinning yard? As described in Example 8.

What are the basic processes for producing staples in existing devices that address the interdependent nature of the six process questions mentioned above? Such a process is provided by the present invention.

SUMMARY OF THE INVENTION

The present invention describes a two-step staple production process using PTT. The first step is extrusion of non-drawing yards (UDY). UDY is converted to a staple fiber product at the second draw production stage.

According to the present invention there is provided a method of making staple fibers from polytrimethylene terephthalate (PTT) in a conventional PET staple fiber making apparatus, comprising: (a) 245 to 253 占 폚, preferably 245 to 250 (B) spinning the extruded PTT with the use of at least one spinneret, (c) moving the spinning jacket to a first take-up roll, wherein the first spinning roll (D) the spinning yarn is cooled to less than 31 占 폚, preferably less than 25 占 폚, more preferably less than 20 占 폚 before reaching the first winding roll, and e) optionally, storing the spinning yard in a climate controlled room at a temperature of 31 ° C or below (both this step and the preceding step are all to minimize premature contraction of the non-drawing yellows prior to drawing processing) (F) preconditioning the yarn at a temperature of at least 60 DEG C, preferably 60 to 100 DEG C, prior to the drawing process, and (g) pre-conditioning the yarn at a temperature of at least 60 DEG C, Draws the yarn at a desired desired second draw (where most of the total draw, most preferably 80 to 85% of the total draw occurs in the first draw, and the second and subsequent draws in the first draw At a temperature of from room temperature to the actual maximum melting point of the glass, preferably from 60 to 160 캜, most preferably from 80 to 100 캜; (h) the drawing is performed at a temperature of less than 190 캜, preferably 100 to 140 캜 (The relaxation may be from 2 to 25% or more, but preferably from 2 to 10%), and after (i) the relaxation step is used, , wind Crimping the drawing yarn at a temperature of 70-100 DEG C if a relaxation step is not used and producing a PET staple comparable to that of a conventional device by drawing a drawing yarn denier to a crimper at 80-120 DEG C In the drafting yard used in the production of the steel sheet, by 10 to 60 denier%, preferably 40 to 60 denier%. Also, or alternatively, the volume of the crimper may be increased by 10 to 50, preferably 20 to 35%, more than the volume of the crimper used to make PET in conventional devices. Preferably, the selection of conditions is based on the particular apparatus and the desired yield.

The poly (trimethylene terephthalate) polymer is a novel polyester resin suitable for use in carpets, fibers and other thermoplastic resin applications. Poly (trimethylene terephthalate) (PTT) is an aromatic polyester resin chemically produced by polycondensation of 1,3-propanediol (PDO) and terephthalic acid. The production of staple fibers from PTT is possible in various industrial processing equipment.

The invention will now be described by way of example with reference to the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of a process step from a resin to a bending fiber,

Figure 2 is a tenderness-elongation curve useful for evaluating a possible range of PTT staple properties,

Figure 3 shows a typical stress / strain curve as a spinning yarn bundle,

Figure 4 shows the effect of extrusion temperature on fiber drawing,

Figure 5 shows the non-drawing yaw contraction in water at different temperatures as a function of non-drawing yaw spinning conditions,

Figure 6 shows an orientation schematic diagram illustrating the effect of fiber shrinkage,

Figure 7 shows the effect of draw bath temperature and total orientation parameters on boiled off shrinkage,

Figure 8 shows the effect of draw bath temperature and total orientation parameters on dry heat shrinkage at < RTI ID = 0.0 > 125 C, <

Figure 9 shows the effect of draw bath temperature and overall orientation parameters on dry heat shrinkage at 140 占 폚,

Figure 10 shows the effect of draw bath temperature and total orientation parameters on 175 ° C dry heat shrinkage,

Figure 11 shows the effect of draw bath temperature and total orientation parameters on 197 ° C dry heat shrinkage,

12 shows the influence of the draw ratio and draw-bath temperature on the draw process relaxation index,

Figure 13 shows the expected dry shrinkage as a function of dryer (diastolic) oven temperature for free relaxation 1.4 total orientation parameters and 75 占 폚 drawback temperature,

Figure 14 shows the effect of the diastolic oven temperature and the applied yaya stretch on dry heat shrinkage at 175 ° C in 100% PTT,

FIG. 15 shows the effect of the diastolic oven temperature and the applied yaya stretch on dry heat shrinkage at 175 ° C for 100% PET,

Figure 16 shows a comparison of 175 ° C dry heat shrinkage of PTT and PET spinning blades at two night setting temperatures,

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

18 shows a comparison of the boil off shrinkage in the PTT and PET spinning fields at two heat setting temperatures,

Figure 19 shows a comparison of PTT and PET spinning yaw loads at 5% strain rate at two night heat setting temperatures,

Figure 20 shows a comparison of the 2 minute percent stress reduction in PTT and PET spinning fields at two spinning night heat setting temperatures,

Figure 21 shows a comparison of percent strain recovery (2 min elongation) in PTT and PET spinning at two spinning yard heat setting temperatures.

Polymer staple fibers are feasible using existing devices. Since the devices used by different companies are very diverse, there will be a difference in how the process is performed. Once the staple producer has set its settings to the unique properties of the PTT, it is possible to produce a variety of staple products suitable for spinning yards and nonwovens. Staple fibers produced from PTT provide excellent loft and drape that provide softness, volume, compatibility in blends, ease of care and shape preservation in textile products.

1.0 Polymer melting

1.1 Resin transport and drying

Low energy air delivery systems minimize dust formation when transporting resin from shipping containers, processing equipment and storage facilities. Prior to extrusion, the PTT resin should be dried to a constant moisture level of 50 ppm or less. This specified moisture minimizes the effect of resin degradation by hydrolysis during melt spinning. Various types of industrial dryers using dried air successfully meet these requirements. Dryers with molecular sieves (13X & 4A), vacuum systems, and lithium chloride desiccants meet moisture requirements in industrial production. If possible, the polymer is preferably dried using 13X molecular sieve dry air (dew point below -40 ° C) heated to 130 ° C with a drying time of 4-6 hours. The use of dry air to transport dried resin from a dryer to an extruder is essential to minimize hydrolysis during melt spinning.

In large industrial dryers, PTT drying at a rate that can keep pace with the extrusion throughput can be attempted. A higher temperature dryer may be required in this situation. The air temperature of the PTT dryer should not exceed 165 ° C. When 165 ° C air is used, the residence time of the dryer should not exceed 4 hours.

1.2 Non-Drawing Ya (UDY) Extrusion

Conventional melt manufacturing systems include extruders, spin beams, melt pumps, and spin packs. The key is to determine a constant optimum melt viscosity of the polymer by minimizing the melt process temperature and residence time. The industrial production of PTT UDY into twin-screw extruder and single-screw extruder is DC. It may be necessary to lower the extruder melt pressure by 25-50% (from the PET conditions) to avoid excessive shear degradation of the polymer melt in the twin-screw extruder. The industrial production of PTT UDY uses an extruder melting temperature in the range of 245 ° C to 270 ° C. Care should be taken to avoid excessive degradation of the polymer melt and impairment of subsequent UDY properties when producing PTT UDY at a melt temperature of 260-270 ° C. The optimum staple extrusion melt temperature for PTT is 245 to 253 占 폚, preferably 245 to 250 占 폚. Future PTT resins with lower intrinsic viscosity will require lower temperatures. Figure 4 shows that excellent drawing is achieved when the polymer is extruded at < RTI ID = 0.0 > 250 C < / RTI >

2.0 Non-Drawing Ya (UDY) Spinning

2.1 Spin Beam, Pump and Pack

Attempts to use one-component and two-component extrusion systems to produce PTT staple UDY have been successful. The spin pump volume and rotation control system sized for PET typically meets low throughput requirements per position for PTT staples. The filtration media should have a minimum pore size of 30 microns. Often industrial spin packs use a minimum amount of filtration media. At the initial stage of deployment of the PTT staple production process, it is desirable to use a standard filtration depth / course sand of the medium (90/120 mesh). The uniformity evaluation of the filament diameter will determine whether the melt pressure of the spin pack filtration or extrusion system needs to be optimized.

The staple extrusion system is operated for a specific range of resin viscosity, throughput, melt temperature and residence time. In general, the hole-throughput required to make PTT staples is typically 20-30% lower than comparable denier PET products. This substantially extends the residence time of the PTT extruded into the PET staple producing device. The extension of the retention time of the melt can lead to decomposition if the melting temperature is higher than 260 ° C. The transport line and the spin beam heating system should preferably be equal to the extruder discharge polymer temperature.

2.2 Employment detention

The spinneret selection is dependent on the desired product denier and is determined by limiting the throughput per minute to stable melt spinning. In general, PTT staples can use standard PET spinneret designs for similar products. However, PTT staples generally require smaller capillary diameters for lower denier products as compared to PET staple production. The PTT resin has a shear rate upper limit of 7500-9000 sec ^-1 for round cross section depending on melt extrusion conditions.

Purpose The selection of spinneret based on the staple product denier is shown in Table 1.

Spinning detention selection chart Excellent denier range at 1100 m / min 1.0-1.3 dpf 1.30-1.75 dpf 1.40-1.85 dpf Diameter of spinning detachment (mm) 0.23 0.25 0.35 Spinning detention ℓ / d 1.85 1.85 1.85-2.0 Limited throughput per hole 0.32 0.41 0.45

It is important that the long fiber vertex area (the distance from the spinneret to the winding roll) be used. This means that the area must be 16 to 20 feet, rather than the standard 8 to 12 feet for PET. In the process, the contraction of the PTT UDY is relatively large so that the process must ensure that the fibers establish a stable molecular structure before all the filaments are combined into one large draw process feed. In the production of PET staple fiber, this is not an important issue. The PTT has a more elastic crystalline form so that a longer fiber vertex link stabilizes the yarn and avoids additional air conditioning costs.

2.3 Quenching

Attempts to use cross-flow and radiation quenching systems have been successful. Radiation quenching systems with airflow in and out of the interior have been successfully used. The fiber bundle should be quenched quickly and uniformly to prevent UDY shrinkage in the spinning supply can. Temperatures of 8-25 [deg.] C are preferred, but quenching temperatures in the range of 8-35 [deg.] C are used. In general, the quench rate is limited by the operability of the UDY thread path. The number of filaments per position is in the range of 350 to 3500 filaments per position. It may be possible to have 6250 upstream filaments per position with the current radiation quenching system in a good denier staple production. Optimization of the quench system involves determining which conditions provide the highest operability and achieve a maximum percent elongation for the desired UDY creel properties.

2.4 Spin Finish

All coatings applied to PTT fibers during staple extrusion and draw production are defined herein as spin finishes. Spin Finish is a fiber coating that provides lubrication, bonding and additive protection to PTT fibers during staple production and downstream processing. Both composite-component phosphates and mineral oil base finishes have been successfully used in the production of PTT staples. Proven PET spin finish chemistry and application methods are also satisfactory for early PTT staple products. The spin finish formulation and application method can then be varied on the basis of consumer feedback in the staple processing.

2.5 coiling

Winding speeds in the range of 900 to 1250 meters per minute were used for industrial PTT UDY production. In the research device, the winding speed of the UDY is in the range of 500 to 2250 meters per minute. It is useful to take a controlled relaxation between the winding capstan roll and the sunflower wheel before fiddling with the tow can. Cooling all filaments below 25-30 ° C at a single location is necessary to minimize UDY shrinkage in the tow cans.

3.0 Tow Drawing and Finishing

3.1 Save UDY

Under normal storage conditions, PTT UDY completes more than 90% of the aging process within 8 hours of extrusion. The UDY draw properties stabilized within 24 hours and no significant change in the draw properties was observed after 2-4 months storage at constant temperature. PTT UDY has the potential to shrink at lower temperatures more easily than PET UDY. Storage conditions warmer than 25-30 ° C should be avoided because they cause UDY shrinkage. Ideally, PTT UDY krill is stored in an air-conditioned environment to avoid shrinkage. The exact temperature at which PTT UDY shrinks will depend on the UDY extrusion, quenching, winding and storage conditions. Even if the PTT UDY shrinks, it is possible to switch this UDY into a first grade industrial staple product during the draw process while minimizing product quality.

3.2 Krill size

The size of the krill for the PTT staple is determined by the size of the production crimper. In general, the krill size for PTT staples is about 60% of equivalent PET staple products due to the larger volume of PTT fibers. A 600,000 denier drawing tow will satisfactorily supply a 110 mm wide x 20 mm high crimper. This can change when the crimper size gets bigger / larger or the draw production speed is faster than 100-130 meters per minute. Increasing the volume of the crimping chamber is another way to improve drawline productivity, as most draw production lines have a maximum line speed of 250-300 m / min.

3.3 Preparation of krill and tow

The PTT UDY is prevented from being heated to 25 DEG C or more until the UDY tow is under a uniform roll tension. This will minimize shrinkage of the PTT supplied to the draw process and maintain uniform fiber tension at all points of the tow section during drawing. If unconditioned non-uniform UDY shrinkage occurs, changes in the can-can orientation will limit the draw process uniformity.

The pre-wetting bath in front of the drawing is preferred, but the temperature should not exceed 25 占 폚 unless dried and nipped rolls are provided in the draw-feed zone to minimize tension. If drive rolls are not available, the jaws shall be at the lowest possible temperature.

3.4 Drawing process

PTT staples are manufactured with draw-relaxation and draw-annealing process arrangements. In the draw relaxation process, staples are heat treated and dried under 0 tension to reduce shrinkage. The process produces low modulus fibers suitable for blending PTT spinning yams and low modulus fibers such as wool and acrylics. The draw annealing process produces a high modulus fiber that is heat-treated to a roll of tow under high tension and more suitable for blending with small amounts of rayon, cotton yarn or other high modulus fibers.

The initial draw point of the UDY tow in the first draw stage must occur in the heated water to a minimum of 60 占 폚, preferably 60 to 100 占 폚. Maintaining the draw point at a high temperature improves the draw process performance by significantly reducing the effect of the extrusion conditions on the draw draw ratio. If necessary, the second draw stage is hotter than the first draw stage to the actual maximum melting point, preferably from 60 to 160 캜, most preferably from 80 to 100 캜. Unlike PET, PTT will not be roughened in a heated drawbath. Additional draw areas are optional and typically extend the overall device draw ratio slightly. The main draw ratio should be taken in the first step.

Annealing or relaxation of the PTT staple tow where 3% roll relaxation occurs in a set of 100-130 < 0 > C calendar rolls increases the initial modulus of the final PTT staple by 12-14%. This process produces PTM spinning yams and high modulus fibers suitable for blending with high modulus fibers such as cotton yarn, rayon and PET. The initial modulus increases about 4% per 10 ° C from 130-150 ° C when the relaxation in the roll set is maintained at 3%. Annealing the PTT tow above 150 ° C may need to increase relaxation in the calender roll to avoid excessive filament breakage. Spin finishes are often applied to compensate for lost spin finishes in a draw process using deep trenches or front / back contact roll applications just prior to the crimping step.

3.5 Crimping

PTT is very easily bent compared to PET tow when given a low flexing rate. This low modulus also provides PTT with excellent feel and softness. In addition, PTT is much more bulky than PET. The low flexing rate and large volume require the following changes in crimping conditions:

The dancer roll and the crimper roll are reduced to better control the crimp geometry.

ㆍ Due to the large volume of the PTT, the feed tow denier should decrease or the crimper volume should increase. The increased volume of the PTT can be best explained by reducing the amount of tow denier supplied to the crimper most preferably by 10 to 60 denier%, preferably by 40 to 60 denier%. Another method is to increase the volume of the crimper by 10 to 50% by volume, preferably by 20 to 35% by volume. Also, a combination of these two methods may be used.

Ideally, the crimper should be equipped with a vapor and spin finish injector to better control the crimping chamber temperature.

It may be necessary to improve the precise regulation of pressure and temperature in the crimping chamber.

Crimp stability and winding are significantly improved if the crimper chamber is at least 85 ° C and the gate pressure is 300 kPa (3 bar). The crimp frequency may be larger than the comparable PET staple and the crimp amplitude may be smaller than the comparable PET staple. Crimp stability and winding are improved when the crimper temperature rises. The crimper should not be heated too much, because staple binding increases as the crimp stability increases, as this can increase deficiencies in consumption.

3.6 Drying, Cutting and Packaging

The relaxation (drying) of the PTT staple in a conventional belt oven is DC. However, as the oven temperature rises above the maximum temperature in the preceding draw process, the crimp geometry and shrink characteristics change. In draw-relaxed staple production, the staple fiber and subsequent spinning yaya dry shrinkage decrease when the dryer temperature rises.

Draw-annealing In production of staples, a relaxation oven is used as a dryer. The airflow rate is relatively fast and the air temperature is relatively low (75-90 ° C) to promote toe drying. These conditions are not high enough to change the staple fiber relaxation or crimp geometry. The staple tow is cut in industrial production using a rotary and adjustable converter type cutter without modification. Gravity and Air Transport Staple balers package industrial PTT staples.

4.0 General methods of 1.7, 2.5 and 3.33 DTEX (1.5, 2.25 and 3 DPF) staples

The draft method for three typical staple products is briefly outlined in the following table. All staple production facilities are different. There will usually be 2-3 attempts on the industrial line to identify industrial processes for PTT staples. This method has been developed in small industrial production equipment. These can change slightly if the process is large-scale with larger devices and high-speed production. UDY is produced using a 253 ° C melting temperature at 1100 m / min. In order to achieve this draw ratio, uniform extrusion conditions are required such that the filament diameter variation coefficient is 3-5% at all spinning positions. In addition, this draw ratio is achieved in modern processing equipment that is very well controlled. It is not strange that outdated equipment only achieves 75-85% of these draw ratios.

The method of Table II also describes a high shrinkage and low shrinkage method for each purpose staple denier. Draw production shrinkage significantly decreases when the first stage draw bath temperature rises above 60 ° C. In addition, the draw shrinkage decreases slightly as the draw ratio increases. Finally, draw production shrinkage in the crimper and dryer is further reduced when calender rolls are used to anneal the fibers. An industrial draw draw speed of 100-130 meters per minute and a draw draw speed as fast as 225 m / min are used. The industrial draw relaxation process typically uses a first draw at 70 占 폚 and a second draw at 100 占 폚. The industrial annealing staple process typically uses a 130 ° C calender roll with a first draw at 70 ° C, a second draw at 100 ° C, and a relaxation of 0.95.

How to draft 1.5, 2.25, 3.0 dpf staples Non-drawing Yaan dpf 4.0 dTex 3.2 dTex 6.4 dTex 6.8 dTex 9.2 dTex 9.7 dTex 1 ^st draw ratio D _^2/1 2.73 2.73 2.74 2.74 2.75 2.75 2 ^nd draw ratio D _^3/2 1.10 1.10 1.15 1.15 1.20 1.20 Device draw ratio 3.00 3.00 3.15 3.15 3.30 3.30 Drawer production relaxes in a crimper and dryer The that The that The that 20% 16% 18% 14% 16% 12% Final staple product 1.7 dTex 1.7 dTex 2.5 dTex 2.5 dTex 3.3 dTex 3.0 dTex

4.1 Staple properties

This discussion of tensile properties assumes that the krillstock is drawn into a 90% tow breakout. Typical draw relaxation PTT staple fibers will typically have a toughness of 2.7 to 3.0 cN / dTex and an elongation of 80 to 90%. A typical commercial draw-annealing staple will have a toughness of 3.4 to 3.5 cN / dTex and an elongation of 60 to 65%. The following tongue elongation balance curve (FIG. 2) is useful in assessing the possible range of staple properties for the PTT. High toughness, low elongation PTT staples are highly producible due to the rapid relaxation of the PTT tow under crimping conditions. Single filament test results on R & D devices show a fiber toughness as high as 4 cN / Tex at 45% elongation. PTT staples with toughness greater than 3.5 cN / Tex can be produced on a highly optimized drawing annealing process. In this effort, adjustment of the crimping conditions will be important.

Example 1 Shrinkage Control in Non-Drawing Yield During Extrusion and Storage

Evaluation of non-drawing yaw shrinkage of PTT UDY spun at two different locations under a wide variety of different conditions. The test results imply that it is best to store PTT UDY below 31 ° C to avoid excessive shrinkage of 2 to 3% or more, as shown in FIG. This chart shows the% shrinkage of the non-drawing yachts immersed in the water bath at several temperatures, 30 캜, 31 캜, 32 캜 and 35 캜. The spinning conditions include the range (dpf) of the drawing product denier per filament in the range of 0.8 to 4.5 dpf and the operating range and winding speed of the throughput for different developed staple production lines at one location A and another location B, respectively. This chart also shows that the PTT UDY shrinkage is a function of the spinning conditions, rather than the quench air temperature. Position A uses 25 ° C quenched air and position B uses 16 ° C quenched air. Excessive shrinkage in non-drawing areas is undesirable because it can increase staple product variability if not properly controlled.

Example 2: Shrinkage of a staple process drawing PTT ribbon

Summary and Conclusion:

Drawing in a bath at 60 ° C or higher eliminates any structural spin effects such as drawing fiber shrinkage.

Drawing fiber shrinkage decreases with increasing draw bath temperature, but this effect is small at temperatures above 60 ° C. Shrinkage also decreases as the total orientation (draw ratio) increases, but this effect is very small at higher bath temperatures. If the drawn shrinkage is enhanced to spin and draw the setting, the crimping becomes more stable and the product becomes less varied. Drawing at temperatures above 60 ° C is recommended, which provides a stable crimping operation.

Expected relaxation factors for crimping and drying / relaxation as a function of dryer / relaxation temperature are made from contraction data. The shape of the curve can be used to estimate accurate and known data, but the magnitude of the factor seems too large.

Product shrinkage as a function of dryer / relaxation temperature appears to be unpredictable from shrinkage data for PTT.

Introduction

The range of spinning conditions tested in the pilot draw line used herein is:

· 240 to 260 ° C block temperature

0.432 to 0.865 g / hole min (0.4 mm capillary)

· 1000 to 2000 m / min spin rate

These supplies were drawn in three draw ratios:

· Breakout draw ratio (BODR) minus 0.1

· BODR - 0.2

· BODR - 0.4

Coupled with a wide variety of spinning orientations, this creates a very wide range of spinning orientations.

Three staple drawer temperatures were used:

· 40 ° C

· 55 ° C

· 70 ° C

This is the maximum range that can actually be operated for the device.

The drawing ribbon was fully characterized. Shrinkage results are analyzed below.

In PTT, PET, and other molten spinning polymers, contraction is a much more sophisticated probe of the fiber structure, unlike the toughness and elongation, which are primarily a function of total orientation, and are influenced by orientation and, more importantly, Receive.

The purpose of this part of the experiment is to answer questions about the following contractions, which are presented in order of importance to process design.

1. Does the drawing maintain a difference in the structure of the spinning yard, or does the drawing process erase them? This is an important hint in the design of spin processes and procedures.

2. How does draw-bath temperature affect shrinkage? Residual shrinkage after drawing is a major factor affecting how easily the fiber can be crimped. In general, much shrunk fibers are easily crimped. If shrinkage is a powerful function of draw bath temperature and orientation, the crimper should be frequently rebalanced to reflect the changing draw conditions and the crimping is less uniform.

3. How much shrinkage occurs when fibers are drawn and crimped, how are they affected by spin and draw conditions? This information is used to calculate the relaxation factor in the spinning model.

4. What additional product shrinkage will exist at higher temperatures when the fibers relax freely in the oven at a given temperature?

The model proved useful for PET has the following premise:

When heated above the glass transition temperature, the fibers will shrink until all the amorphous regions are out of alignment, unless they are re-deformed.

As the temperature rises above the glass transition temperature, the additionally oriented amorphous regions appear to melt the crystals. This newly created amorphous region is then de-oriented to provide additional shrinkage. Therefore, generally, the higher the temperature, the greater the shrinkage.

Some definitions are currently required that are somewhat inherently cyclic. The glass transition temperature is defined as the temperature at which the unreformed amorphous chain is free from de-orientation, as required by the second law of thermodynamics. The amorphous region is a non-crystalline region. The crystalline region is the region that is not de-oriented at this temperature. There are a number of ways to define crystalline regions in terms of TGA curves, X-ray trends, densities, etc., and also yield more or less different but related solutions in terms of percent crystalline. For the purposes of this discussion, we will define determinations in terms of their orientation maintenance capability at temperature.

In essence, this model assumes that heat treatment of the rope only results in crystalline fusion and fiber de-orientation. This model works well for PET loosening within the process with short pause times. This works well for a staple process that involves several minutes of pause time, but its validity for PTT has not been known before this work.

The length, orientation diagram in Fig. 6 can be used to describe the method. This diagram shows what happens when drawing fibers from their length to the sample fiber length, l _f , in zero birefringence. When this fiber is heated to T ₁ temperature, all amorphous regions are de-oriented and lost to length l ₁ because all the unstable crystals melt to T ₁ and are de-oriented.

The fibers are not fully de-oriented, because there is still a stable crystal at T ₁ . When the temperature is raised to T ₂ , the additional crystals melt, are amorphized and de-oriented, and the length is further reduced. You may think that it will be able to shrink completely at a zero birefringence draw ratio of 1.0, but in fact, there are some crystals that are stable to and above the melting point (which causes problems in PET polymerization). They are not out of alignment and thus the reorientation can never be complete.

With the above introduction, the experimental questions can now be solved.

Does the drawing retain the difference in the spinning structure?

It may be expected that shrinkage will be a powerful function of the draw ratio, since it provides a lost orientation. For PET, this is true to a certain extent, but its effect is broadened by the fact that as the orientation is increased, the ability to form the crystalline region also increases and the opposite effect of the orientation increase exists. Also in PET at elevated draw bath temperatures, all spinning memory is erased until shrinkage is a concern. The orientation can be approximated as the total alignment parameter TOP (denier draw ratio / intrinsic draw ratio).

In order to calculate the intrinsic draw ratio, it is necessary to measure the appropriate strain rate for the laboratory apparatus and the technique that produces reproducible results. Single spinned spinning tubes at 40 # / hr, 240 캜 and 1500 m / min are tested at strain rates of 200 to 800% per minute. Three repetitive measurements are performed with the curve tracked on a single graph. The results imply good laboratory techniques and equipment and are highly reproducible at all strain rates. All measurements yield characteristic curves illustrated in FIG. The inherent draw ratio can be easily calculated from these plots as follows.

NDR = l + (S _n / 100) (1)

Where S _n is the% strain at the native draw strain rate.

This is equivalent to the classical definition of NDR as follows.

NDR = l _d / l _s (2)

From here,

l _d is the length at the natural draw inflection point,

l _s is the length of the spinning sample.

The first step is to establish what variables are statistically significant in the contraction expected at a given temperature. The procedure used a regression procedure one step forward in Sigma Stat 2.0 followed by one step forward by entering F> 4.0 and rejecting P <0.05.

The results summarized in Table 3 imply:

Procedures were generally consistent.

At a draw temperature of 60 ° C or higher, spinning parameters do not play an important role in fiber shrinkage.

The total orientation parameters and, surprisingly, the block temperature was a significant factor in the shrinkage at a 45 ° C draw temperature.

Draw temperatures above 60 ° C are used to eliminate any spinning effects on product shrinkage. This data supports the hypothesis that, like PET, the spinning structure is eliminated when a draw temperature significantly higher than T _g is used. The regression equation for correlation with r ² > 0.5 is presented in the table below. Note that there is no T> = 60 ° C.

Regression analysis of ribbon contraction Draw bath temperature ℃ Shrink Forward test Backward test variable r ² variable r ² 45 Boyle Off TOP, T _b 0.666 TOP, T _b 0.666 ⁽¹⁾ 45 125 ℃ TOP, T _b 0.695 TOP, T _b 0.695 ⁽²⁾ 45 140 ° C TOP, T _b 0.540 TOP, T _b 0.540 ⁽³⁾ 45 175 ° C TOP, T _b 0.489 TOP, T _b 0.441 45 197 ° C TOP 0.126 TOP 0.126 60 Boyle Off Q _h 0.190 Q _h 0.153 60 125 ℃ TOP 0.188 Q _h 0.131 60 140 ° C TOP 0.241 TOP 0.241 60 175 ° C AVE na AVE na 60 197 ° C AVE na AVE na 75 Boyle Off AVE na AVE na 75 125 ℃ Q _h , S _m 0.273 Q _h , S _m 0.273 75 140 ° C AVE na AVE na 75 175 ° C AVE na AVE na 75 197 ° C AVE na AVE na TOP = total orientation parameter = (denier draw ratio / intrinsic draw ratio) T _b = block temperature, ° C Q _h = hole throughput, g / minute S _m = spinning speed, m / min AVE =

How does draw-bath temperature affect shrinkage?

Figures 7-11 are plots of boil-off shrinkage at 125, 140, 175, and 197 ° C, and dry heat shrinkage for the three drawbath temperatures used. It is evident that there is a large mechanism change at 45 to 60 DEG C, and the next higher temperature is tested. At temperatures above 60 ° C, the shrinkage is almost independent of orientation and is relatively insensitive to the bath temperature.

Higher bath temperatures reduce the shrinkage potential in small amounts, but not significantly in terms of crimping potential or expected product performance.

Operation at temperatures above 60 ° C is recommended, because the crimper operation is very simple. Crimper adjustment under these conditions is not required (denier / linear crimper inches, dtex / linear crimper cm), except for compensation with a crimper for denier density.

How does spinning and draw-bath temperature affect relaxation factors?

Analysis of Figures 7 to 11 and the variables suggests that the contraction potential of the drawn rope is independent of the spinning conditions and only weakly depends on the orientation, except at the lowest temperature tested, 45 占 폚.

Figure 12 shows the relationship between the oven temperature and the relaxation factor for the drawn rope. At a draw-bath temperature of 60 ° C or higher, the line through top-grouping of the data points approximates the relaxation factor. This is a good starting point, but its value can be too high (too low shrinkage) because the shrinkage method uses a small amount for the sample and is therefore not completely free to relax, as in a typical factory equipment dryer / divergence.

However, the curve can have an accurate shape and is therefore suf fi cient to estimate the temperature effect when more machine-specific data is obtained.

Can relaxed product shrinkage be expected from ribbon shrinkage data?

Referring to Fig. 3 and the simple shrinkage model for PET, when the fibers at l _f enter the oven at T ₁ , the amorphous orientation will be lost and some of the crystals will melt and de-orientate and their length will decrease to l ₁ . Similarly, the length l _f in the sample in this case placed in an oven at a temperature T ₂ higher than T _1, more will be the more crystalline material melting at a high temperature will further shrink because shrinkage in the length l _2.

Mathematically, the shrinkage ratio can be expressed by the following equation:

Ф ₁ =% Shrinkage @ T _{1/100 (1)}

With Ф ₂ =% Shrinkage @ T _{2/100 (2)} d,

Then from the definition of dry heat shrinkage:

_{Ф 1 = (l f - l} 1) / l f = l- l 1 / l f (3)

Ф ₂ = l - l ₂ / l _f (4)

What happens if a freely relaxed sample at T ₁ is tested for shrinkage at T ₂ ? If no changes other than crystalline growth or melting and de-orientation occur during the first shrinkage process, it will shrink to l ₂ .

Following the first contraction, which is the fiber experience in the diastole, the second contraction is the residual contraction in the relaxed product. To some extent PET can follow this assumption and thus measure relaxed product shrinkage from dry heat shrinkage of the drawn ribbon.

What has to be calculated for this is the shrinkage when the product contracted at T ₁ contracts at the second time T ₂ . This can be done using the definition of shrinkage and Figure 3 as follows.

Ф _ps = (% shrinkage of sample shrunk at T ₁ when shrunk at T ₂ ) / 100 (5)

Φ _ps = (l ₁ - l ₂ ) / l ₁ = l - l ₂ / l ₁ (6)

When equations 3 and 4 are used to cancel l ₁ and l ₂ in terms of dry heat shrinkage measured at two different temperatures measured, the following equation is derived:

Φ _ps = 1 - (1 - Φ ₂ ) / (1 - Φ ₁ ) (7)

From this, the measured shrinkage at T ₂ , the expected product shrinkage after oven relaxation at T ₁ can be calculated.

Figure 13 is a plot of the expected contraction for a technique that is useful in the case of high orientation and high air temperature. The expected fiber shrinkage after a given oven relaxation appears to be too low. This suggests that significant crystalline changes in addition to simple de-orientation occur in the dryer / diastole.

Example 3: Evaluation of PTT staple fiber heat setting on properties on PTT spinning yam characteristics under heated deformation conditions: Evaluated yam including PTT, PTT / PET blend, PTT / cotton blend, and PET (Table 5).

The destruction of filaments during the extrusion of PTT synthetic fibers seriously limits product productivity and quality. A PTT resin having an IV in the range of 0.55 to 1.0 is preferred, more preferably an IV of 0.675 to 0.92, and most preferably an IV in the range of 0.72 to 0.82. Producing PTT synthetic fibers having an intrinsic viscosity in the range of 0.72 to 0.82 helps improve synthetic fiber production workability and quality without severely reducing final fiber properties.

Reducing the intrinsic viscosity of the PTT helps:

1. Reduces the amount of change in viscosity of the chip compared to the viscosity of the extruded fiber.

2. Improve the homogeneity of the polymer melt in the spin pack. PTT resins with 0.92 IV require a more rigorous spin-pack filtration system to maintain marginal production at extrusion.

3. Improves production workability by reducing the number of broken filaments during production.

4. Allow the product to run at a lower extrusion temperature for extruded filaments with less than 2 deniers per filament. PTT is known to decompose at a melt extrusion temperature of 260 ° C or higher. When producing fine denier synthetic filaments (filaments with less than 2 dpf) using 0.92 IV resin, excessive melt flow turbulence causing filament breakage during extrusion and melt extrusion to reduce melt viscosity sufficient to avoid melt breakdown The temperature should be increased.

5. Reduce the shrinkage of the product fibers, which makes the process easier to draw and / or to wind on a stable yarn package.

The staple yarn made of PTT is surprisingly an elastomer having recoverable elasticity when stretched to 15-25% of its original length. This elasticity also exists when the staple yarn is produced from homogeneous and non-homogeneous fiber blends, where the PTT is the major fiber component by weight and / or length. Further, such elasticity can be recovered even after several hundred cycles. Elasticity is sufficient to improve the shape retention characteristics of fabrics produced from PTT staple yarns and blended staple yarns. Suitably constructed and finished fibers containing most of the PTT staple spinning yarns (by weight% of the length) can have surprisingly high elastic recovery in woven fabrics and knitted fabrics (500 cycles by hand and 200 cycles by machine) ). The present invention encompasses the formation of staple spinning yarns by converting staples into twisted yarn structures by any method. The spinning yard can be made by manual, spinning, ring-spinning, opening spinning, air-jet spinning, or other devices that convert staples to light.

Staples made of cotton, wool, acrylic, and PET are inelastic. In order to produce staple yarns from these elastic fibers, industrial processes generally add elastic continuous filaments internally to the yarns or knits to produce the final fabric product elasticity. These solutions are more expensive than base staple spinning yards made of PTT. The value of the present invention is that those with a basic staple spinning yam technique will have a commercially valuable elasticity without the need to invest more expensive core spinning yarn equipment or incorporating elastic continuous fibers complicating the dyeing and finishing of the fibers into the fabric structure It can produce spinning yards.

Efforts were made to simply characterize how the staple fiber heat setting characteristics affect the behavior of the bladed PTT staples and blended PTT staples and blended PTT staples. As shown in Table 4, PET and cotton blending yarns are made from various PTT staple feeds that are produced with significantly different crimp temperatures at different diastolic temperatures. Therefore, the effect of blending with other fibers can not be confirmed definitively. Therefore, attention is used to deduce the exact blending level effect from these experiments. This experiment examines each of the examples in terms of shrinkage, modulus, stress attenuation and recovery. These factors are generally independent and have been studied separately in this work.

Fiber properties Item number PTT5-CR1-2 PTT5-CR1-3 PTT-CR1-4 Fiber relaxation oven temperature, ℃ 105 120 135 Fiber denier / filament 1.75 1.80 1.79 Toughness, cN / dtex 3.52 3.49 3.24 Elongation to failure,% 48 45 44 Load at 10% strain, cN / dtex 0.83 1.21 1.13 Hand Crimp Index,% 28 19 18.5 Crimp / inch 14.8 15.8 14.2 Ya'an created 100% PTT 50% PTT and 50% cotton 50% PTT and 50% PET

Summary and Conclusions

Spinning Yaan About 175 ℃ dry heat shrinkage

Spinning Yayan dry heat shrinkage was reduced at oven temperatures for all blends tested (100% PTT, 100% PET, 50/50 PTT / PET, and 50/50 PTT / cotton).

Dry heat shrink is increased by about 1/2 for 1% of applied stretch (or relaxation) for all tested blends.

PTT contractions were 2 to 2 and 1/2% less than those of PET.

The PTT data closely follow the amorphous de-orientation model for shrinkage.

· About spinning yard boil off contraction

The boil off shrinkage was reduced at the oven temperature for all tested blends.

· Boyle off shrinkage increased by about 0.4% for 1% of applied stretch for all tested blends.

· The PTT spinning field was about 1% lower than the PET field at the boil off shrinkage because the PET sample was made by draw relaxation while the PET sample was drawn by the draw relaxation process.

About Spinning Yaan Road at 5% Strain (Stretch)

The fabric is considered to be " stretchable " when very little force is required to vary its length in significant amounts. In such an attempt, we choose to characterize the stretch by observing the force required to deform the fabric 5%. The main variable affecting all blends tested is applied stretch. The oven temperature is much less important, and this evaluation implies that:

· PTT shows 3 to 4 times less force than PET to elongate 5%.

The amount of stretching of PTT is reduced by 1/10 ^th of PET (0.01 gpd increase / 1% stretch vs. 0.1). Thus, the applied stretch can be used for PTT to modify the yaw characteristics without a large yaw stretch penalty.

The stretch in 100% PTT was insensitive to relatively heat setting conditions.

Spinning Ya Stress Attenuation

The extent to which the yarns or fabrics are recovered after being subjected to a given deformation for a given period of time depends on two factors:

1. The amount of stress damping that occurs during deformation.

2. Recovery amount after deformation is released.

These factors are generally independent and have been studied separately in this work.

The PTT stress attenuation was independent of the thermal setting temperature and decreased linearly with increasing applied stretch (0.5% reduction in stress attenuation / 1% applied stretch at thermal setting).

The PET stress attenuation decreased linearly with increasing the applied stretch as the oven temperature was increased. The applied stretch effect is much stronger than PTT (-0 / 9% per applied stretch).

· PTT and PET show approximately the same amount of stress attenuation.

· The PTT / PET blending field is reduced by -0.7% per percent of applied stretch and acts approximately halfway between the corresponding pure fields.

The PTT / cotton blending yaw stress attenuation was independent of the thermal setting conditions.

Spinning yayan recovery

Recovery of PTT field from these sample sets was much less than that observed in the recently tested pre-market sample with 98% recovery. The cause may be a 100 &lt; 0 &gt; C dryer oven used in textile processing. The main thermosetting variables affecting recovery for all samples tested are applied stretch, and an increase in applied stretch increases recovery:

· PTT recovery increases by 0.9% per 1% applied stretch.

PTT generally has a recovery rate of 5-10% higher than PET.

· The PTT / cotton blend data were very irregular but showed the same general tendency as the pure field.

Shrinking principle

In semicrystalline polymeric fibers with significant orientation, the orientation is in two regions, the crystalline region, and the amorphous region connecting the crystalline domains. Typically, there is a range of crystal sizes, and the orientation of the crystalline region may vary.

When the fiber is exposed to a temperature below the glass transition temperature, the change in length is very slow and is referred to as a creep. Generally, all of the useful fabric fibers have a low creep rate under the rod member. When the fibers are heated to a temperature above Tg, the amorphous regions become mobile and, in the absence of binding forces, are de-oriented as they approach an isotropic state (no preferred orientation). The isotropic state is preferred by the second law of thermodynamics. This usually results in shrinkage, but in rare cases the crystalline zone collapses on its own and a " negative " These fibers are called self-extensible. It is not known whether they can be made from PTT. The crystalline region is not mobile and is not de-oriented.

As the temperature of the fibers is continually increased, smaller crystals are melted and their domains become amorphous. They are now out of alignment and additional shrinkage occurs. This is because shrinkage generally increases with temperature for the semi-crystalline polymer. There are therefore two strategies for reducing fiber shrinkage:

1. Pre-shrink to the desired temperature to stabilize the fiber.

2. Crystallization under heat and tension at temperatures producing stable crystals at temperatures where fiber shrinkage is not desired.

For everyday commodity PET fibers, if the issue is spinning and weaving efficiency and night strength, the second path is used exclusively, as will be seen later, because the pre-shrink reduces the fiber modulus. Particularly, special fibers for wool blends use the first path because strength and modulus are not important issues, but because of the advantage of better saltability provided by path 1. At this time, it is not clear which is the better path to the PTT.

When the fibers are stretched, their amorphous orientation increases, and thus shrinkage also occurs. In PET non-twisted continuous filament yarns, there is often a one-to-one correspondence (5% stretch increases the contraction rate by 5%).

Thus, Applicants have discussed a single non-crimping fiber. The situation for spinning yards is more complicated, for the following reasons:

The fibers are twisted at a helix angle which reduces the effect of fiber shrinkage in the field.

The fibers move from the outside to the center of the yard.

Fiber can slip in the field.

The presence of blend fibers with different shrinkage rates can change the shrinkage of the assembly.

Despite this complexity, Applicants can use a simple model to predict the response of the spinning field to the thermal setting conditions:

1. If the yarn is heated and relaxed freely, then it is de-oriented and the crystallinity increases. Both factors reduce contraction. At constant oven temperatures, shrinkage reduction is linear with the relaxation. The shrinkage decreases with increasing oven temperature.

2. If the yarn is heated and kept at a constant length, there is no de-orientation. As the oven treatment oven temperature is higher than the fiber experienced during the free relaxation phase in fiber production, the shrinkage decreases with increasing oven temperature.

3. When the yarn is heated and stretched, the orientation increases and thus the shrinkage also increases. Shrinkage increases with applied stretch and straight line, decreases with increasing oven temperature, and is higher than that seen during short fiber processing.

Based on this in place, Applicants are now ready to analyze the effect of the thermal setting conditions on the yaya contraction.

175 ℃ Spinning Yaya Dry heat shrinkage

As illustrated in Figure 14, the PTT is a good substrate to adhere to all the rules of the overall orientation model.

In a 0% applied stretch, the relaxed control at 100 占 폚 has exactly the same shrinkage as the treated at 100 占 폚. When treated at a higher temperature, the shrinkage decreases at a constant length.

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

PET also behaves in a similar manner (Figure 15). Since this is an annealed fiber and is not a relaxed fiber, the shrinkage in the control field decreases with increasing oven temperature even at 100 占 폚. Because of the high modulus, the fibers do not stretch at high stretch and low oven temperatures, but the increase in shrinkage due to slip at night is not as great as in PTT. For oven temperatures above 130 ° C, dry heat shrinkage increases by about 0.55% per 1% applied stretch. This is somewhat higher than PTT, but a good approximation for both is a 1/2% contraction increase for each% stretch.

Figure 16 compares PTT and PET yam shrinkage for the highest and lowest set temperature. PTT has a dry shrinkage of about 2 to 2 and 1/2% lower than PET for equivalent oven conditions. Both have approximately the same increase in shrinkage to the applied stretch as described above.

The PTT / cotton blend is similar to a PET blend (Figure 17) with reduced oven temperature and increased shrinkage with increasing applied stretch. The increase in applied stretch is fairly linear, and the shrinkage increases roughly by 0.47% per 1% applied stretch. The shrinkage of the cotton blend is approximately 1% lower than the PET blend for similar conditions. A good rule of thumb for this sample set is that a 1% applied stretch increases the dry heat shrinkage by 1/2%.

Spinning Ya Boyle Off Shrink

The boil off shrinkage behaves in the same way as dry heat, except that the available amorphous orientation is in the fiber + which melts between the glass transition temperature and 100 ° C and is present in all crystals, and is therefore much less than dry heat shrinkage. In the case of some fibers with a high plasticizing effect of water, such shrinkage can be significant. Fibers produced by the draw relaxation process at a relaxation temperature of 100 DEG C or higher generally have a very low boil off shrinkage. Annealing fibers generally have a relatively high boiling off shrinkage rate because they are heated under tension and always present in an amorphous orientation.

These samples generally follow these principles. All blends behaved in a manner similar to dry heat shrinkage with increasing oven temperatures with reduced shrinkage and increased application stretch.

The PTT contrast yarn has a shrinkage of 2%, but the fibers contained therein are oven-relaxed at 100 &lt; 0 &gt; C. This indicates that some room temperature drawing occurred during processing, perhaps during carding. This is unexpected given the low modulus of PTT. PTT yaya shrinkage increased about 0.38% per 1% applied stretch. Control PET has significantly higher shrinkage than PTT (4.5 to 2%) because it is produced by the annealing process. Yaya shrinkage increased by 0.47% per 1% applied stretch. Assuming a similar yellowness setting condition, the PTT field generally has a dry shrinkage of about 1% less than the PET field (Fig. 18).

The PTT / PET blend yarn has a shrinkage increase of 0.44% per 1% applied stretch and the PTT / cotton yarn has an increase of 0.417. A good approximation to the boil-off shrinkage increases about 0.4% per 1% applied stretch for all conditions tested.

For a 100% PTT spinning field, the load at 5% strain is linearly related to the applied stretch, which is virtually independent of the oven temperature and increases by 0.01 gpd per 1% increase in applied stretch. This means that the yank stretch is reduced as the yang is drawn during the thermal setting. Note that for the PTT data, the contrast yarns generated from 100% relaxed fibers have substantially the same load at 5% strain as compared to zero stretch and heat setting at 100 占 폚.

PET night acted in a similar way. In this case, there is a significant change to the heat setting at the control oven vs. 100 ° C and zero applied stretch because the feed fiber was annealed but not relaxed. At 5% elongation, the PET rod increases the applied stretch to 0.1 gpd / 1% applied stretch to a larger number of digits than the PTT.

Figure 19 compares the behavior of PTT and PET, and the stretch advantage of PTT is remarkably obvious. Without the applied stretch 3 a lower coefficient force is required at the 5% strain rate and the response to the applied stretch is much less, meaning that the applied stretch can be used for thermal setting in the PTT without expensive cost in the yaya stretch do. Interestingly, maximum applied stretch PTT items (7.5%) require 45% less force at 5% strain than 7.5% relaxed PET samples.

Spinning Ya Stress Attenuation

The amount of deformation of the yarn or fabric after a certain amount of deformation and a certain length of time is restored depends on two factors:

How much stress attenuation occurs while the sample is held at a constant length. Extremely, when all the stress is lost, the recovery is zero.

How much stress is recovered after the test period.

This spinning yam stress attenuation experiment involves a 5% deformation of the yam, followed by a spinning yam for 2 minutes at that length, followed by a recovery of the yam to zero stress. Stress damping is calculated manually from the test chart and is somewhat less accurate than the mechanical calculated values from computer analysis. Stress damping and recovery are two distinct phenomena and are discussed separately.

The stress attenuation in 100% PTT is independent of the oven temperature and is reduced to the applied stretch and straight line. Intuitively, r2 for this correlation is very high, while stress attenuation is thought to increase with applied stretch. The PTT stress attenuation is reduced by about 0.5% per% applied stretch. PET yarns behave in a similar manner, but there is a constant oven temperature effect and the reduction per unit applied stretch (0.9% attenuation / 1% applied stretch) is almost twice that of PTT. Figure 20 compares PTT and PET stress attenuation. In general, PET is higher at lower applied stretch, lower at higher oven temperature and applied stretch than PTT. The behavior of the PTT / PET blend is intermediate between the two pure fibers with less oven temperature sensitivity and a 0.7% stress attenuation reduction per 1% applied stretch. The stress attenuation for the PTT / cotton blend is independent of the thermal setting conditions.

Spinning yayan recovery

PTT recovery is unaffected by oven temperature and increases linearly with increasing applied stretch (0.9% recovery per 1% applied stretch). PET recovery slightly increases with increasing oven temperature, but the main effect is applied stretch. Its response is even more pronounced for PTT with an increase in the 2.2% recovery rate for each 1% applied stretch. As shown in FIG. 21, PTT generally has a recovery rate of 5-10% higher, except when PET has a high level of applied stretch in a high temperature oven. The PTT / PET blend yarn reacts like a pure PTT without oven temperature dependency and responds strongly to the applied stretch (1.7% recovery for each 1% applied stretch). The PTT / cotton blend results are irregular with two higher oven temperatures and higher applied stretch increases the recovery rate.

Exchange of characteristics in spinning yard heat setting

One of the main reasons for doing this is to answer the following questions: "How much heat, and how much reduction of the shrinkage of the yarn reduces the stretch, recovery and stress attenuation?". To answer this question for these data sets, it is necessary to construct these variables for each other. Since all variables are dependent variables, the relationship is true only for this data set and others that have changed the dependent variable in the same way as we did here. Let the reaction be observed under this clue:

For stretch / dry heat shrink exchange, the stretch increases as the dry heat shrinkage decreases (the load decreases at 5% strain). This is a good deal because there is no strength penalty to be done by reducing contractions by letting Ya'an shrink. Considering that all points are included, although r2 is very low at 0.47, this data is probably a reliable trend guide. The load at 5% reduces 0.01 gpd for each 1% reduction in shrinkage.

Recovery / dry shrinkage exchange is unreliable. For each 1% reduction in dry heat shrinkage, the recovery rate decreases by 1.3%. The r2 for this data was considerably 0.64.

Stress damping / dry heat shrinkage exchange is unreliable due to a stress attenuation of 0.9% for each 1% reduction in dry heat shrinkage. This increase in stress attenuation is believed to be the cause of the decrease in recovery rate. In either case, dry heat shrinkage should be reduced to the minimum amount required by the end user.

Example 4: Reduction of resin PTT resin IV from 0.92 to 0.82 provides improved extrusion reliability in PTT staple production

Destruction of filaments during extrusion of PTT synthetic fibers severely limits productivity and product quality. The production of PTT synthetic fibers having an intrinsic viscosity range of 0.72 to 0.82 helps improve synthetic fiber production workability and product quality without significantly reducing the final fiber properties.

The intrinsic viscosity reduction of PTT helps to reduce the viscosity change of the chip compared to the viscosity of the extruded fiber. This also improves the homogeneity of the polymer melt in the spin pack. PTT resins of 0.92 IV require a more rigorous spin pack filtration system to maintain a marginal yield in extrusion. This also helps to improve production workability by reducing the number of filaments broken during production. This allows the product to be run at colder extrusion temperatures for extruded filaments having less than 2 deniers per filament. PTT is known to decompose at a melt extrusion temperature of 260 ° C or higher. In the case of producing fine denier synthetic filaments (filaments less than 2 dpf) using 0.92 IV resin, excessive melt flow turbulence, which would cause destruction of the filaments during extrusion, and melting to reduce melting viscosity sufficient to avoid melt decomposition The extrusion temperature should be increased. It also reduces the shrinkage of the product fibers, making it easier to draw the process and / or to wind it on a stable yarn package.

Claims (10)

(a) melt extruding the PTT polymer at 245 to 253 DEG C, (b) spinning the extruded PTT by hand using at least one spinneret, (c) moving the spinning yard to a first winding roll, wherein the distance from the spinning nip to the first winding roll is 16 to 20 feet, (d) cooling the spinning jacket to less than 31 캜 before reaching the first winding roll, (e) optionally, spinning the yarn is stored at a temperature of 31 DEG C or less, (f) Prior to the draw process, the yarn is pre-conditioned under tension at a temperature of at least 60 ° C, (g) drawing the yarn at a temperature of at least &lt; RTI ID = 0.0 &gt; 60 C, (h) optionally allowing the drawing yarn to relax at a temperature up to &lt; RTI ID = 0.0 &gt; 190 C, (i) reducing the drawing yard feed rate by 10 to 60% by denier from the drawing yard feed rate used in the PET manufacturing to crimp and match the drawing yard at a temperature of 70 to 120 &lt; 0 &gt;C; A method for producing fabric staple fibers from polytrimethylene terephthalate (PTT) on an existing PET fabric staple fiber manufacturing apparatus. The method of claim 1, wherein the intrinsic viscosity of the PTT is from 0.55 to 1.0. 3. The method of claim 2 wherein the intrinsic viscosity of the PTT is from 0.72 to 0.82. The method according to any one of claims 1 to 3, wherein the spinning jacket is cooled to less than 25 占 폚 before reaching the first winding roll. The method of claim 1 wherein the relaxation step is not used and the crimping temperature is 70 to 100 占 폚. The method of claim 1 wherein the relaxation step is used and the crimping temperature is 80 to 120 ° C. The method according to any one of claims 1 to 6, further comprising the step of using a creamer volume of 10 to 50% more than the crimper volume of the crimper used in the production of PET comparable to step (i) How to. The method according to any one of claims 1 to 7, wherein the drawing yard feed rate is reduced by 40 to 60%. (a) melt extruding the PTT polymer at 245 to 253 DEG C, (b) spinning the extruded PTT by hand using at least one spinneret, (c) moving the spinning yard to a first winding roll, wherein the distance from the spinning nip to the first winding roll is 16 to 20 feet, (d) cooling the spinning jacket to less than 31 캜 before reaching the first winding roll, (e) optionally, spinning the yarn is stored at a temperature of 31 DEG C or less, (f) Prior to the draw process, the yarn is pre-conditioned under tension at a temperature of at least 60 ° C, (g) drawing the yarn at a temperature of at least &lt; RTI ID = 0.0 &gt; 60 C, (h) optionally allowing the drawing yarn to relax at a temperature up to &lt; RTI ID = 0.0 &gt; 190 C, (i) using a crimper volume of 10 to 50% more than the crimper volume of a crimper used in the manufacture of PET to crimp and match the drawing yarn at a temperature of 70 to 120 DEG C, A method for producing fabric staple fibers from polytrimethylene terephthalate (PTT) on an existing PET fabric staple fiber manufacturing apparatus. The method of any of the claims 1-9, wherein step (g) is accompanied by at least two draws, wherein the first draw is performed at least at &lt; RTI ID = 0.0 &gt; 60 C &lt; RTI ID = 0.0 &gt; 1 &lt; / RTI &gt; draw.