JPS5976917A - Production of yarn having high heat shrinkage stress - Google Patents

Abstract

PURPOSE:To obtain the titled yarns having a high heat shrinkage stress, improved waterproofness without deteriorating the moisture permeability and air permeability, and useful as rainwear, etc., by drawing undrawn polyester yarns having a specific birefringence and high orientation degree under specific conditions. CONSTITUTION:An undrawn polyester yarn 1 having >=45X10<-3> birefringence (DELTAn) and high orientation degree as a feed yarn is passed through a yarn guide 2, wound around a heated roll 3, delivered, wound around a stretching roll 4, drawn under such conditions as to satisfy formula I [E is the residual elongation (%) of the undrawn yarn to be fed to the drawing; DR is the total draw ratio; D is >=1.05] and formula II [Tg is the glass transition temperature ( deg.C) of the undrawn yarn fed to the drawing; RT is the surface temperature ( deg.C)] of the heated roll 3 for the fed yarn in drawing and then wound into a pirn 6 to give the aimed yarn having >=0.7g/denier heat shrinkage stress.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyester fibers having high heat shrinkage stress (hereinafter referred to as shrinkage stress).

When a drawn polyester yarn is heated to an elevated temperature, the maximum shrinkage stress that occurs during the external temperature process is extremely high.For example, drawn yarn is woven with a high-density structure and made into waterproof fabrics such as rainwear and sportswear. In this case, it is extremely effective in improving waterproofness without impairing moisture permeability and air permeability, and the present invention provides a method for easily producing polyester fibers that can be effectively used in these applications. It is something.

Fabrics used for rainwear and sportswear are required to have waterproof performance without compromising moisture permeability and air permeability. Although there has not been a waterproof fabric that has the contradictory properties of moisture permeability, air permeability, and complete waterproofing, waterproof fabrics that are satisfactory to a certain extent have been developed.

In principle, these are waterproof.

(1) A film in which a waterproof polymer film is stretched and made into a veigrilled film with extremely small holes e+ is laminated to cloth or sandwiched between two cloths.

(2) Normally used long fiber yarns are woven at extremely high density during weaving to extremely reduce the porosity between the yarns and single filaments, giving it waterproof performance.

etc. are known as typical manufacturing methods. Among these, waterproof fabrics woven with a high-density structure have a soft texture (not stiff. Even when handled hard, the porous film does not crack or peel off like the one described in (1) above. This method can be said to be more advantageous than the method using a porous film that has been made into a vee grill because it is possible to weave the yarn as it is without any processing.

To produce waterproof fabric using high-density woven fabric, if the fabric is heat-set or heat-dyed after weaving, lt! ! It is extremely important that the woven yarn shrinks uniformly. That is,
When the shrinkage stress of the threads used in m-weaving is small, the frictional resistance between the threads and the single yarns becomes high due to the high density structure, causing uneven shrinkage between the threads and the single yarns, and as a result, voids are formed. This results in a fabric that has moisture permeability and air permeability but extremely low waterproof performance due to variations in the ratio.

In this way, even if we take the example of yarn used in high-density fabrics aimed at waterproofing, it is difficult to manufacture yarn with high shrinkage stress.
This is necessary to make products with high added value, and the manufacturing technology is extremely important.

Conventionally, when manufacturing polyester long fiber yarn, undrawn yarn with a low degree of orientation, which is wound at a spinning speed of i, about 5oon15+, is used as a supply system, and the residual elongation of the yarn after drawing is 25 to 35%. A common method is to stretch the film at a stretching ratio such that the film is stretched, perform constant length heat treatment, and then wind it up on a burner. However, the shrinkage stress of the yarn drawn by these methods is as low as 0.4 to 0.59/denier at most. Also, if you want to further increase the shrinkage stress,
It is known that the shrinkage stress can be improved by extremely increasing the draw ratio and drawing temperature during drawing, but when undrawn yarn with a low degree of orientation is supplied for drawing, increasing the draw ratio will result in 1 fluff or more. The number of yarn breakages increases rapidly, and as the stretching temperature increases, stretching unevenness is more likely to occur, resulting in yarn breakage and dyeing unevenness, so the stretching temperature should be set between (Tg+5) and (Tg
g+10) °C is the limit.

As described above, when drawing is performed using undrawn yarn with a low degree of orientation, it is not easy to obtain a yarn with high shrinkage stress, and it is difficult to obtain a yarn with high shrinkage stress without deteriorating the manageability or quality (8+!! It is extremely difficult to create.

The present inventors solved two or more problems and produced yarn with high shrinkage stress at N 1M without deteriorating workability or yarn quality.
After careful consideration of a method for this purpose, we found that we used undrawn yarn with a high degree of orientation, which had been wound up using a high-speed spinning method, as a supply system to draw the yarn.

(1) Even if the residual elongation of the drawn yarn is not reduced by increasing the draw ratio, the shrinkage stress shows a higher value than when a low-oriented undrawn yarn is drawn, and even if the draw ratio is increased, Because the initial orientation of the supplied yarn is high, there is little yarn breakage during stretching, making it stable.

This results in a yarn with extremely high shrinkage stress.

(2) Similarly, even if the drawing temperature is extremely high, it is stable against heat, and a yarn of stable quality can be obtained without yarn breakage during drawing or uneven dyeing of the drawn yarn.

Based on this knowledge, they continued to conduct further studies and arrived at the present invention.

That is, 9 the present invention has a birefringence index (Δn) of 45X10~1
A polyester undrawn yarn with a high degree of orientation as described above is used as a supply system, and the shrinkage stress is 0.79/denier or more, and is stretched under conditions that satisfy the following formula (2). This is a method for manufacturing polyester high shrinkage stress yarn.

(100+E)/146≦DR≦(100+E)/11
6 −(])Tg+30≦RT≦Tg+85
...(2) In the formula, E: Residual elongation (%) of the undrawn yarn supplied for drawing DR: Total stretching ratio, provided that DR≧1.05Tg: Glass transition temperature of the undrawn yarn supplied for drawing ( (°C) RT: Surface temperature (°C) of the supply system heating roller during stretching.

As the polyester yarn referred to in the present invention, it is most desirable to use polyethylene terephthalate having ethylene terephthalate as a repeating unit.

Even if a copolymerized Borienether containing 85 mol% or more of the repeating unit is used, there is no hindrance.

In addition, the shrinkage stress of the stretched yarn is high.

In addition, in order to stabilize operability and quality, it is necessary to use yarn supplied during drawing that has a birefringence index (Δn) of undrawn yarn wound up using a high-speed spinning method, etc. of 45 x 10' or more. It is.

The birefringence (Δn) of the undrawn yarn supplied during drawing is 45X
If a thread of less than 10-3 is used, the above-mentioned thread breakage and dyeing spots are likely to occur during drawing, and the target value of 0, 79/
It is therefore impossible to obtain a drawn yarn having a shrinkage stress of one denier or more.

That is, in order to efficiently produce a high shrinkage stress yarn under special drawing conditions, which is the object of the present invention, the birefringence (Δn) of the undrawn yarn to be supplied for drawing must be 45X10-'! It is necessary to do more than that.

Furthermore, if a residual elongation of 30% or more is required for the drawn yarn, the birefringence index (Δ
The higher the value of n), the better.

65x10-' or more is preferred.

Equation (1) shows the relationship between the residual elongation (F) of the supplied undrawn yarn and the total draw ratio (DR) in the drawing system.

The regulation of the total draw ratio (DR) in the present invention is necessary in relation to shrinkage stress and drawing operability. In other words, the residual elongation of the drawn yarn changes depending on the residual elongation of the undrawn yarn supplied for drawing and the total draw ratio (DR).
Less than (100+E)/146 (DR)
When stretching is carried out, the shrinkage stress decreases, making it difficult to obtain a yarn with high shrinkage stress such as the one produced by the present invention, and the residual elongation increases, which is undesirable as it causes elongation when made into a fabric. It is.

Also, greater than (100+E)/116 (DR)
When stretching is carried out, surprisingly high shrinkage stress yarns can be obtained, but the occurrence of yarn breakage during stretching is undesirable. Therefore, the total stretching ratio during stretching (
DR) needs to be set within the range shown by equation (1).

In addition, during spinning, the spinning speed is set to, for example, 5,000 m/
In this case, the residual elongation of the undrawn yarn (the phantom is such that the elongation is so low that it does not require drawing) is wound up. In the present invention, no matter how low elongation undrawn yarn is supplied, it is necessary to heat-draw it at 1.05 or more in the drawing system in order to obtain a high shrinkage stress yarn.

Also, residual elongation (%) of undrawn yarn supplied during drawing
The measurement is carried out using a tensile test machine such as Instron, and an undrawn yarn of sample length i o <ex> is pulled at a speed of 10
This is the elongation at the maximum stress when the undrawn yarn starts to break at 017 minutes).

The temperature (RT) of the heating roller is (Tg+30
)°C to (Tg+85)°C.

That is, the temperature (RT) of the heated loaf is (Tg+30
) Celsius, the effect of the draw ratio on the shrinkage stress is extremely large and unstable under 9 conditions.9 The goal of the present invention is to stably produce yarn with a shrinkage stress of fl, 7 f/denier or more. It is not possible.

Also, the temperature (RT) of the heating roller is (Tg+85)
If the temperature exceeds .degree. C., softening or breakage of the yarn tends to occur during drawing, which is not preferable in terms of obtaining stable operability.

The glass transition temperature (Tg) can be measured using a differential scanning calorimeter, etc. 1For example, if the undrawn yarn supplied for drawing is polyethylene terephthalate, the glass transition temperature is approximately 7.
5°C, in this case the temperature of the heating roller (RT)
is 105°C or higher.

The temperature is preferably 160° C. or lower, and the temperature can be appropriately selected within this range depending on the fineness of the undrawn yarn supplied for drawing, the type of oil agent used during spinning, and the target shrinkage stress.

The higher the shrinkage stress of the yarn supplied to M'S the fabric, the more stable the quality will be, and the better the fabric can be obtained.9 For example, when weaving waterproof fabric or highly twisted fabric, After heat setting or heat dyeing, the shrinkage of the yarn shrinks, resulting in high waterproof performance and fine grain. The shrinkage stress of the yarn supplied to the weave must be at least 0.7 V/denier, and if the shrinkage stress is less than 7 g/denier, the absolute B of shrinkage (B) is small and the yarn is The yield u will vary due to FFM resistance between the intermediate yarns and other factors, and as a result, the waterproof performance will be low, the grain will become rough, and the fabric will be of low quality. When producing twisted fabrics, it is desirable that the shrinkage stress of the supplied yarn be at least 0.7 Q/denier IJ, l.
7.

In addition, when manufacturing fabrics, it is easy to consider increasing the 117 shrinkage ratio of the supplied yarn to compensate for the low shrinkage stress, but even in this case, friction between the yarns and single yarns and the fabric Within the tissue, contraction is restricted so that it can fully contract.

This is undesirable because it causes variations in the amount of shrinkage, and furthermore, because the shrinkage rate of the yarn supplied for weaving is high, the variation in °C is expanded compared to yarn with a low shrinkage rate, leading to a decline in quality. be.

The effect of the present invention can be achieved without any particular restriction on the single fiber fineness of the undrawn yarn supplied for drawing, but as the single yarn fineness becomes thinner, the degree of orientation increases even at the same spinning speed, and the crystal orientation increases. As a result, yarns with higher shrinkage stress can be obtained, which is advantageous.Also, if you want to obtain fabrics with high added value such as waterproof fabrics and high-twist fabrics, weaving It is preferable to supply a yarn having a fineness of fineness and high shrinkage stress, and it is more preferable to use a yarn having a single yarn fineness of 0.7 denier or less after drawing. It is.

Shrinkage stress in the present invention is defined as follows.

That is, after measuring the fineness (D) of the yarn whose shrinkage stress is to be measured, the sample yarn forming a loop with a length of 10 (ffi) was heated at 5 W using a heating machine made by Kanebo Engineering Co., Ltd. /denier initial load, and the temperature was raised at a temperature increase rate of 1.67°C and 70mm.

Shrinkage stress (Y
axis) on the XY recorder. Assuming that the shrinkage stress at the peak point of the shrinkage stress-temperature curve is Fp (q), the shrinkage stress in the present invention is defined by the following equation (3).

Shrinkage stress (9/Denny/I/): FS=Fp/2D
(3) Examples of embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing the process of using an undrawn yarn as a supply system and winding the yarn into a burner after heating and drawing the yarn when carrying out the present invention, but this method is not necessarily limited to this method. For example, there is no problem even if a multi-stage stretching method is used. However, when dividing the cold draw ratio (DR) using a multi-stage drawing method, for example, 1
It is necessary to set the stretching ratio in the two stretching systems to 1.051 μH, and care must be taken because shrinkage stress tends to decrease when relaxation treatment is performed.

The supply system 1 passes through a yarn path guide 2, is wound around a heating roller 6, and is sent out. After being wound around a drawing roller 4 having a circumferential speed ratio of at least 1.05 to the heating roller 2, and stretched, The thread is fed out through the thread guide 5 and is fed to the bar 76.
It is rolled up. In this case, when winding the yarn around the heating roller or drawing roller, it is necessary to wind the yarn to such an extent that no slip occurs between the roller surface and the yarn. 0.05 in order to prevent slippage and at the same time to sufficiently preheat the yarn.
It is preferable that the heating contact be carried out for more than a second.

As is clear from the examples, the yarn with high shrinkage stress obtained by the production method of the present invention can be used to weave high value-added fabrics that require yarn with high shrinkage stress, such as waterproof fabrics. Although the effect is remarkable, it is of course not limited to this.

The present invention will be explained in more detail below with reference to Examples.

'J,? lpa is C] 11 Hard i. Viscosity [η] is 0.65 and glass transition temperature (Tg)
Melt polyethylene terephthalate at a temperature of 5°C,
By varying the winding speed during spinning through a 72-hole spinneret, undrawn yarns with different birefringence indexes (Δn) were collected.

The temperature (RT) of the heating roller was set to 125°C (T
g+50), and the stretching ratio (DR) was set to I
)R=(100+E)/136, and the fineness of the drawn yarn is 5.
A yarn having a denier of 0 and a number of filaments of 72 was obtained. The shrinkage stress of the yarn was measured using the thermal stress measuring machine described above, and the yarn was knitted in a tube, and the evaluation results are shown in Table 1.

Example 2 Example 1 (The birefringence index (Δn) of the undrawn yarn collected at a spinning speed of 3,500 m/min was 55
．． Using an undrawn yarn of 0x10-3, the heating roller temperature (RT) was kept constant at 125°C (Tg+50),
The shrinkage stress of the obtained drawn yarn was measured by changing the draw ratio (DR) variously, and the results are shown in Table 2.

Example 5 Using the same undrawn yarn as in Example 2 as a supply system and using the same equipment as in Example 1, the heating row two temperature (RT) was varied at a constant IA stretching ratio (DR) of 1.46. The shrinkage stress of the resulting yarn was measured.

The results are shown in Table 3.

\ \ Example 4 The same polyethylene terephthalate as in Example 1 was melted, passed through a spinneret, and wound up at a spinning speed of 3,500 ml/min. A highly oriented polyethylene terephthalate with a birefringence index (Δn) of 87.3'X10- An undrawn yarn was collected.

The undrawn yarn was drawn using the same drawing device as in Example 1 under the conditions that the heating roller temperature (RT) was 135°C (Tg+60) and the drawing ratio (DR) was 1.22 (100+E/136). As a result, the residual elongation of the drawn yarn was 28.
．． At 2%, a drawn yarn having a shrinkage stress of 0.929/denier and a single yarn fineness of 0.51 denier was obtained.

Using this yarn, the warp is 169*/inch and the weft is 81
A tacked fabric was woven with a weave density of 1.5 inches, and after undergoing a series of processes such as presetting and dyeing, a water pressure test was conducted on the fabric, and it remained completely waterproof even when water pressure of over 1,500 mm was applied. A waterproof fabric with extremely high waterproof performance was obtained.

In contrast, a drawn yarn with a shrinkage stress of 0.61 g/denier, which was drawn under conditions outside the scope of the present invention using the same undrawn yarn, was woven and dyed with the weave structure introduced in Example 4. When we conducted a length water pressure test on the fabric, the water pressure was 600 mi! J is the limit, and it was found that the fabric using the yarn obtained by the present invention has extremely excellent waterproof properties.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a drawing/twisting machine which is an example of an apparatus for producing the high shrinkage stress yarn of the present invention. 1: Supply undrawn yarn 2: Yarn path guide 5: Heating roller 4: Stretched loaf 5: Yarn path guide 6: Burn patent applicant Yuzo Kodama, agent of Nippon Ester Co., Ltd.

Claims (2)

[Claims] (1) Highly oriented polyester undrawn yarn with a birefringence index (80) of 45×10-' or more was used as the supply system. A method for manufacturing a polyester-based high heat shrinkage stress yarn having a heat shrinkage stress of 0.79/denier or more, which is characterized by carrying out stretching under the conditions of increasing bulk (r) and (2). (+00+E)/146≦DR≦(100+B)/11
6-(1,)Tg+50≦RT≦Tg-1-85
-(2) where a: Residual elongation (%) of undrawn yarn supplied to IA medium DR=
Total stretching ratio, provided that DR≧1.05Tg: Glass transition temperature (°C) of undrawn yarn supplied to FE drawing R'I': ) Surface temperature (°C) of heating row two of supply system during TE drawing. (2) j, If: The method for producing a polyester-based high heat-shrinkable stress yarn according to claim 1, wherein the single yarn warpage after stretching is 0.7 denier or less.