KR800000069B1 - Method of preparing a polyester fiber - Google Patents

Abstract

Polyester fibers contained>=85% ethylene terephthalate repeating units and had denier (1.58-0.05N), tenacity 6.3-7.2g/denier, elongation 25-30%, modulus 2.2-3.5g/denier were melt-spun with draft 380%, lubricated, drawn 380% at 70≰ and 108% at 90≰, heat-treated at 180≰ under tension, heated to 85≰, crimped, packed on metal screen conveyer to packing d. 270g/m3. heat-treated at 140≰, and cut to 38mm length to give 1.26 denier fiber with tenacity 6.8g/denier, elongation 27%, modulus 3g/dinier, and shrinkage 5.5%.

Description

Manufacturing method of polyester fiber

The figure is an enlarged view of the crimped fiber.

The present invention relates to a method for producing a polyester fiber which can be made into a spun yarn of good quality with good spinning properties of polyester fibers.

Polyester fiber is used alone or mixed with cotton, hemp, rayon, etc., and is widely used as a spun yarn.

As a method of improving the spinning property of such polyester fiber, it is common to perform high strength, low elongation, and high modulus of a fiber. As a result, the speeding up of the square most required in the spinning process is achieved to a certain extent without involving deterioration of the process state (particularly, increase in trimming). However, such high strength, low elongation, and high modulus fibers are difficult to crimp, resulting in poor crimping performance (particularly, denier is higher). Spinning characteristics related to focusing properties and winding properties such as lap formation, lapping property, carding property, and coil formation are greatly reduced.

In addition, the low elongation increases the number of trimming in the spinning, weaving, and knitting processes of the yarn.

The present inventors have conducted research on polyester fibers which do not have the above problems, and as a result, polyester fibers containing 85 mol% or more of ethylene terephthalate units (a) single yarn denier 1.58-0.005N or less (where N Is the number of spun yarns), (b) breaking strength of 6.3 7.2 g / d, (e) breaking elongation 25-30%, (d) modulus at 10% elongation, 2.2-3.5 g / d, (f) 180 ° C 30 Dry heat shrinkage for 4 min 4-7% (g) Primary crimp crimp 11-15 / 25mnb (h) Primary crimp crimp 10-13%, (i) Second crimp crimp 10-14 / 25cm (j ) Secondary crimp crimping can be done at high speed (18,000-20,000rpm, ie 19-21m / min) only for fibers with 10-20% physical properties and crimping performance. The present invention has been achieved by finding that the focusing and winding properties in the previous step are good, and that there is little threading in the case of breakfast or knitting.

As the polyester, polyethylene terephthalate is most suitable, but the third component (isophthalic acid) P-hydroxy benzoic acid, glycol having 3 or more carbon atoms, etc. is copolymerized for the purpose of improving dyeing or anti-pill property, or other polymer (nylon). A small amount of polyolefin, etc.) may be mixed, and the intrinsic viscosity of the polymer (in 0-chloro phenol-35 DEG C) is most suitably in the range of 0.50-0.70.

The cross-sectional shape of this fiber is not limited to circular, but may be trilobal or wnd ball.

The single yarn denier (D) needs to be D≥ 1.58-0.005N depending on the target N of the spinning yarn (English). It is not preferable that the single yarn dewage is larger than this range because a lot of trimming occurs in the square of 18,000-20,000 rpm and the strength of the obtained spun yarn also decreases in spite of other conditions.

In addition, the breaking strength (TS) of the fiber and modulus (M ₁₀ ) at 10% elongation also affect the strength of trimming and spun yarn in high-speed spinning, with TS less than 6.3 g / d and M ₁₀ 2.2 g / d. If less than, the trimming of the square increases, the strength of the yarn is significantly reduced.

However, TS> would of 7.2g / d M _10> 3.5g / d in it is not preferable because not only are difficult to manufacture without happen to involve the deterioration of performance or other properties crimped deteriorated dyeability. The breaking of the fibers The elongation (TE) influences the elongation of the yarn, and if the TE is less than 25%, the elongation of the yarn is insufficient, and it is easy to cause the thread to be trimmed due to abnormal tension during breakfast or production.

However, TE does not need to exceed 30%, but rather TE> 30% is not preferable because physical properties deteriorate.

In addition, the knitted fabric is generally heat-set near 180 ℃, in order to maintain the dimensional stability of the fiber is required to have a dry heat shrink (DS) of 180 ℃, 30 minutes in the range of 4-7%.

Crimping performance mainly affects anterior connection and winding property, but the forward operation is good only when the primary crimp and the secondary crimp are within the following ranges.

Primary crimp crimp (CN) 11-15 / 25mm

Crimping degree (CD) 10-13%

Secondary crimp crimping water (CN) 10-14 / 25cm (preferably 11-13)

Crimping degree (CD) 10-20% (preferably 13-18%)

In addition, the primary crimp here refers to the three crimps which can be blown in a normal indentation crimping house, and it is 1,1 'of the figure.

The crimp number and crimp degree of the primary crimp are measured by JIS-L1,060.

Secondary crimps are those of large corrugated portions ranging from 2 to 2 'in the figure. The crimping number and crimping degree of this secondary crimp are the values calculated by the following equation when the length is ₂ l after standing for 2 minutes with a load of 0.15 mg / dl on short fibers.

The polyester fiber having the above-mentioned inferiority and crimping property was thought to be difficult to manufacture conventionally, but can be produced by the method of the present application.

That is, the unstretched tow obtained by melt spinning the polyester is stretched at a draw ratio of 1.02 to 1.08 in a cold draw ratio, and then subjected to tension heat treatment at 160 ° C to 180 ° C, followed by emulsion treatment of the tow, followed by indentation crimping in a wet state. At the same time, steam is injected into the crimp box of this press-fit crimp and then placed on a conveyor connected to the heat treatment machine in a filling chute with a tow filled at a packing density of 250 kg / m 3 or more. It can be produced by performing free shrinkage heat treatment at a time and finally cutting to a predetermined fiber length as necessary.

In this method, melt spinning can be carried out by a conventional method, and the resulting undrawn yarn is drawn at a draw ratio of cold drawing magnification (CDR) 1.02-1.08 with a tow of 50,000 to 1,000,000 denier.

Here, the cold drawing ratio means that the undrawn yarn is left in a room at 20 ° C. to 30 ° C. and RH 50 to 70 ° C. for 12 to 48 hours, and then cut into a fiber length of about 30 cm and a sub tow of 2,000 to 3,000 deniers is used. ), And the draw ratio at the time of stretching until the tensile stress rapidly rises at a tensile rate of 30 to 50 cm / sec in the room of the temperature and humidity.

This cold draw ratio is mainly changed by birefringence of the undrawn yarn, and the CDRs of the undrawn yarn radiated by the conventional method are usually in the range of 3.5 to 4.5 times. It is preferable to perform the above stretching in a water bath at 60 to 100 ° C., and if necessary, the stretching is divided into two stages and stretched in a first bath at 60 to 80 ° C., and then stretched in a second bath at a first bath temperature to 100 ° C. do. In the production of ordinary polyester fiber for spinning, pre-stretching is performed after pre-heating the stretched tow as it is or about 100 ° C, but in the present invention, the stretched tow is subjected to tension heat treatment at l60 ° C to 180 ° C.

This treatment involves (a) running a tow in contact with a heating plate. (B) Tow is carried out zigzag between heating rollers. (C) Although it can carry out by methods, such as letting a row | pass into a heating chamber, which heat treatment time is preferable about 0.5 to 10 second.

The tow heat-stretched in this manner is then tanned. Emulsion treatment can usually be carried out by making the tow through a bath of an emulsion emulsion or emulsion aqueous solution, or spraying it with a mulzone or an aqueous solution.

In the present invention, the tow in the wet state needs to be supplied to the press-fitting crimp by the oil treatment, so that the fluid treatment is preferably performed immediately before the crimping. Press-fit crimps can be used as usual, but the crimp box needs to be sprayed with steam.

Water vapor is enough to be around 100 ° C. The tow extracted from the crimper is loaded on the conveyor via a chute and subjected to free shrinkage heat treatment.

At this time, the tow is supplied on the conveyor, for example, by using the apparatus of JP 46-22 883. At that time, the filling density of the tow supplied to the conveyor by adjusting the traveling speed of the conveyor is 250 kg. It is necessary to set it as / m <3> or more.

That is, the crimped toe is twisted at an approximately 90 ° angle by a torsion guide device, and is provided with a c-shaped shoe-shaft installed below by an entry tube which swings about a point from below. That is, the long side of the upper hole is approximately equal to the amplitude of the entry tube, and the long side is stored while being folded in a zigzag shape to the curved chute so that the length of the long side is constant downward and parallel to the conveyor. do. In addition, it is possible to arbitrarily adjust the filling density of the tow by adjusting the running speed of the conveyor and adjusting the amount of the tow deposited in the shoe chute.

In addition, as long as the tow can be supplied in a standing state with a packing density of 250 kg / m 3 or more on the conveyor, there is no problem even if an apparatus other than the L-shaped chute is used. Moreover, it is necessary to make heat processing temperature at this time into 120-150 degreeC. The heat treated tow is thus cut to the desired length as needed. The polyester fiber obtained as described above is improved in lapping cutting, lapping, cart winding, etc. when spun alone or blended with other fibers (cotton, rayon, hemp, etc.). Speeding can be achieved.

For example, when commercially available polyester SF is blended at a ratio of polyester 65 / cotton 35 and made into a yarn of 45'S, the spinning speed was only about 16,000 rpm, but in the present invention, the spinning speed is 18,000 to 20,000 rpm, and the strength of the yarn is Re-strength) is also increased and in the above example, the conventional one was raised to 31 to 32 kg, which was only 29 kg.

In addition, the efficiency of the breakfast, weaving, and knitting processes is increased by 5 to 20%.

Next, embodiments of the present invention will be described in detail.

In addition, the lap leaking in the example is evaluated by the following five levels of the occurrence of leaking when lapping.

5 very good

4 good

3 approximately good

2 Somewhat bad

1 bad

In addition, the card winding degree is a measure of the card passability of the cotton and is an indicator of the amount of cotton remaining on the card cloth in the normal operation state. Stop and measure the amount of residual surface discharged from the needle roller after the supply stops. The card winding degree is a value obtained by dividing the amount gr of the remaining surface by the average sliver thickness g / m.

Square trimming is the number of rounds per hour per square spinning machine.

In addition, the thread trimming at the time of manufacture is a value which converted the number of cuttings of the warp and weft yarn into the number of cuts per one hour while operating a manufacturing machine, and is the value which was converted by operating five days for five days normally.

Example 1

70 ° C after emulsifying the unstretched tow (CDR = 3.8 times of this tow) obtained by melt spinning a polyethylene derephthalate having an intrinsic viscosity of 0.64 as measured by a 0-chromo phenol solution at 25 ° C. Stretched 3.8 times in the first extension jade at 1.08 times in the second extension jade at 90 ° C., and increased the total draw ratio to 4.1 times, followed by zigzag movement of the five heating rollers held at 180 ° C. After the heat treatment under tension, the sample was preheated to 85 ° C. in a pre-bath and supplied to a press-fit crimper, and crimped while spraying water vapor on the crimper.

A better crimping tow in the crimper is filled in a L-shaped shoe-shaped chute with a packing density of 270kg / m3, and is then supplied onto the wire mesh conveyor while maintaining the packing density and continuously free-shrinked to 140 ° C by hot air. After cutting, it was cut into short fibers of 38 mm length as a cutter.

Next, when spinning using each cotton, sliver mixing was performed in the softening process at a ratio of 65% polyester / 35% cotton, and the square spinning 45 'S at 24T / in of soft water. .

The results at this time are shown in the first table.

[Table 1]

(Texture Properties and Spinning Properties)

Example 2

In Example 1, the radially stretched heat treatment and spinning were carried out in the same manner as in the tension heat treatment except for changing the heating roller temperature, the presence or absence of steam injection in the crimper, and the tow packing density during free shrinkage heat treatment as shown in Table 2-1. It was done.

The results are shown in Table 2-2.

[Table 2-1]

(Manufacturing conditions)

[Table 2-2]

(Texture Properties and Textiles)

Example 3

In Example 1, except that the unstretched tow CDRs and stretching conditions were changed as shown in Table 3-1 below, the radially stretched heat treatment and spatula were performed in the same manner. The results are shown in Table 3-2.

[Table 3-1]

(Expansion condition)

[Table 3-2]

(Surface characteristics and spinning properties)

Example 4

In Example 1, spinning was carried out by spinning simultaneously with the exception that the free water side heat treatment conditions were changed as in Table 4.

[Table 4]

Claims (1)

The unstretched fiber tow obtained by melt-spun polyester containing 85% or more of ethylene terephthalate unit is stretched at a draw ratio of 1.02 to 1.08 in a cold draw ratio, and then subjected to tension heat treatment at 160 to 180 ° C, and then the stretch heat treatment tow is After the treatment, press crimping is performed in the wet state. In addition, water vapor is injected into the crimp box of the press crimping machine, and the tow filled with a packing density of 250 kg / m3 or more is placed in the filling chute. A method for producing crimped polyester fiber, which is placed on a conveyor to be subjected to free shrinkage heat treatment at a temperature of 120 ° to 150 ° C.

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