KR100426588B1 - A method of preparing for a sea-island typed composit fiber used in warp knitting - Google Patents

Abstract

The present invention relates to a method for producing a warp island-in-the-sea composite fiber, and using 50-90 denier for warp knitting using an alkali-soluble copolyester as a sea component and a conventional polyester as a sea component. When manufacturing island-in-the-sea composite fiber, the following conditions are simultaneously satisfied.

-Below-

Speed of the first high roller (V ₁ ): 1,000 m / min to 3,000 m / min

Speed of the second high roller (V ₂ ): 4,000m / min to 6,000m / min

Yarn modulus on the first high roller ≤ 20 g / d

Yarn crystallinity on the second high roller: 25 to 45%

The island-in-the-sea composite fiber prepared by the present invention has excellent yarn modulus after elution of sea component, thereby minimizing yarn damage during raising, thereby improving the feel and appearance of warp knitted paper.

Description

A method of preparing for a sea-island typed composit fiber used in warp knitting}

The present invention relates to a island-in-the-sea composite fiber for warp knitting.

The island-in-the-sea composite fiber is manufactured by using an alkali-soluble polymer as a sea component and a fiber-forming polymer as a island component, and composite spinning them into an island-in-the-sea type, mainly for the purpose of producing ultrafine fibers. Is being produced. In other words, after preparing the island-in-the-sea composite fiber, it is treated with an alkaline solution to elute the sea component which is an alkali-soluble polymer, thereby producing an ultrafine fiber composed only of the island component.

As described above, the method of manufacturing the ultrafine fibers from the island-in-the-sea composite fiber has the advantages of superior spinning and stretching operations and more fineness of fine fibers compared to the method of manufacturing the ultrafine fibers by direct spinning. After knitting, the process of eluting and removing the sea component polymer with an organic solvent in a processing step is required. Therefore, the sea component polymer is very important to be easily dissolved in an organic solvent or a solution, and yarn modulus after sea component elution.

In general, alkali-soluble copolyester is mainly used as the sea component polymer used in the island-in-the-sea composite fiber. The reason for this is that the dissolution of the sea component is possible in alkaline solutions and weight reduction facilities which are widely applied in weight reduction processing of general polyester fabrics without the use of special equipment and costly organic solvents.

When the water-based polymer is nylon, the dissolution rate of the sea component is not very important because the degree of nylon invasion by the alkaline solution is very low when the sea component is eluted. If the speed is low, the island component is violated before the sea component is completely eluted, and the yarn strength is drastically lowered after the dissolution. As a result, the raising properties are poor and it is difficult to express the appearance and feel of the target final product.

On the other hand, if the dissolution rate of the sea component is fast, not only the occurrence of the above problems can be suppressed, but also the alkali concentration, elution temperature and time can be reduced, thereby reducing the elution cost and increasing productivity. However, in order to increase the dissolution rate of the sea component, the content of the copolymer compound should be increased. However, when the content of the copolymer compound is excessively increased, the elution property is improved, but the melting point of the polymer is eliminated and it is an amorphous polymer having only a softening point. It becomes difficult. In addition, the yarn before the eluting strength is lowered, the brushing occurs when the brush is entangled with each other, and the polymer manufacturing cost increases due to the increased input of the copolymer compound.

Conventional techniques for producing alkali-soluble polyesters used in the preparation of island-in-the-sea composite fibers include, firstly, dimethylisophthalate sulfonate salt (hereinafter referred to as "DMIS") or low molecular weight polyalkylene glycols (hereinafter referred to as "polyester") during the polyester polymerization process. The method of copolymerizing "PAG", the method of blending the second polyester and the high molecular weight PAG, and the method of blending the third polyester polymer and the high molecular weight PAG are known.

Conventional islands-in-the-sea composite fibers prepared by the conventional spinning direct stretching method using the alkali-soluble leaching polyester described above as the sea component and the polyester as the island component have a high degree of the island component by the alkaline solution during the sea component elution process. There is a problem in that the yarn crystal orientation after damage is eluted. As a result, in the subsequent raising process after warp knitting, the yarn was severely damaged and dropped, resulting in a deterioration in brushing and deteriorating the appearance and quality of the warp knit.

It is an object of the present invention to provide a method for producing island-in-the-sea composite fibers which are particularly useful as warp yarns because of excellent yarn crystal orientation after sea component elution to solve such problems.

The present invention is to provide a method for appropriately controlling the speed of the first high roller and the second high roller, the yarn physical properties during the weaving process in order to minimize the degradation of the yarn crystal orientation in the sea component dissolution and raising process. Specifically, by controlling the yarn modulus, crystallinity, and birefringence of each step of the weaving process to an appropriate range, it is intended to provide a method of minimizing the physical property degradation of the yarn during dissolution or raising the sea component. In another aspect, the present invention is to provide a method for producing an island-in-the-sea composite fiber particularly suitable as warp yarn.

1 is a process schematic diagram of the present invention

※ Explanation of main parts in drawings

DESCRIPTION OF SYMBOLS 1 Spinner detention 2: The 1st high roller 3: The 2nd high roller 4: Winder

The method for producing warp island-in-the-sea composite fiber of the present invention for achieving the above problems is 50 ~ 90 by the direct stretching method using an alkali-soluble copolyester as a sea component and a conventional polyester as a island component In manufacturing the denier warp island-like composite fiber, it is characterized by satisfying the following conditions simultaneously.

-Below-

Speed of the first high roller (V ₁ ): 1,000 m / min to 3,000 m / min

Speed of the second high roller (V ₂ ): 4,000m / min to 6,000m / min

Yarn modulus on the first high roller: 5 ~ 35g / d

Yarn crystallinity on the second high roller: 25 to 45%

Hereinafter, the present invention will be described in detail.

First, in the present invention, alkali-soluble co-polyester is used as a sea component, and ordinary polyester is used as a island component, and these are combined-spun into a conventional island-in-the-sea composite spinneret 1. At this time, 3-15 mol% of DMIS is copolymerized with polyethylene terephthalate, and copolymerized polyester etc. which added 4-20 weight% of polyethyleneglycols whose number average molecular weight is 8,000 or more are used here.

Subsequently, the present invention draws the spun yarn while passing through the first go roller 2 and the second go roller 3, and winds it up with a winder 4 to produce an island-in-the-sea composite fiber. In other words, the present invention is produced by the spinning direct stretching method in which spinning and stretching are performed in the same process. At this time, the speed V ₁ of the first high roller is set at 1,000 to 3,000 m / min, and the speed V ₂ of the second high roller is set at 4,000 m / min to 6,000 m / min. When the speeds of the first high roller 2 and the second high roller 3 are lower than the above ranges, sufficient alignment of the yarn is not achieved, so that a yarn of low strength and high elongation is produced. As a result, there is a problem that the uniformity at the time of raising and the weight loss during the loss are severe, making it difficult to use as a warp knitting yarn. On the other hand, if it is higher than the above range, the birefringence and density of the yarn are sharply lowered, which causes a problem that warp knitting workability and post processing fairness are lowered.

In addition, it is characterized in that the yarn physical properties at each step (position) of the spinning process is adjusted as follows.

First, the manufacturing conditions are set such that the yarn modulus on the first high roller, that is, the yarn modulus passing through the first high roller, is 5 to 35 g / d. If it is out of the above range, the modulus, density and orientation of the yarn are drastically lowered in the drawing section, so that the drawing process becomes very difficult, or is unsuitable as warp yarn.

In addition, the manufacturing conditions are set so that the degree of yarn crystallization on the second high roller phase is 25 to 45%. If it is lower than the above range, too much stress is applied in the drawing section, so that the drawing process is difficult due to trimming, etc., and the yarn physical property is lowered. If it is higher than the above range, the filament is stiff and is not suitable as a warp yarn. Is generated.

Further, it is more preferable that the yarn birefringence Δn under the detention becomes 0.001 or less. If the yarn birefringence under the crest exceeds the above range, the position at which the filament solidifies crystallizes closer to the surface and the stress applied to the filament increases too much. As a result, problems such as trimming occur.

The yarn modulus on the first roller is cut at the front end of the first roller and then wound on the surface of the first roller, almost simultaneously with the capture of the spinning aspirated yarn at the rear end using capture. It is a value obtained by taking a sample immediately after cutting and measuring the yarn modulus by the method described below. More specifically, during sampling, the filament located on the surface of the filament layer wound on the first roller is collected, and immediately cut to prevent the change of yarn properties by the temperature of the first roller.

The degree of crystallinity of the yarn on the second roller is cut at the same time as the yarns of the yarns being spun at the front and rear of the second roller by using a capture, and the sample of the filament wound on the surface of the second roller is immediately cut. It is the value which measured the degree of crystallinity of yarn by the method. If the sample is not taken immediately after the yarn is cut, the yarn properties may change with the temperature of the second roller.

Yarn birefringence under detention is measured using a capture of 1 m in length from the spinning point of the spinning yarn, and then the birefringence is measured by the method described below. The birefringence is a value obtained by treating the sampled island-in-the-sea composite fiber (sample) in a 1% NaOH solution for 30 minutes to elute the sea component among them and measuring it with a polarizing microscope as described below.

In the present invention, a warp island-like composite fiber having a total fineness of 50 to 90 denier having a single yarn fineness of 2 to 4 deniers prior to sea component elution and a 0.001 to 0.3 denier single yarn fineness after sea component elution is produced. The island-in-the-sea composite fiber produced by the method of the present invention has a yarn modulus of 25 to 60 g / d, an elongation of 40 to 60%, an intensity of 2.0 to 4.0 g / d, and a crystal orientation (Fc) of 0.80 to 0.95 after sea component elution. to be. After knitting the warp knitted paper with the island-in-the-sea composite fiber prepared by the method of the present invention, the sea component is eluted with an alkaline solution and brushed to prepare a brushed warp knit. The dissolution of the sea component is carried out by treating the island-in-sea composite fiber with 95 ° C. for 30 minutes in a 1% sodium hydroxide solution (bath ratio = 10: 1).

The island-in-the-sea composite fiber produced by the method of the present invention is minimized in yarn property degradation during the sea component elution process or brushing process due to the elution property and yarn property characteristics of the sea component. As a result, the raising property is improved, and the appearance and feel of the warp knitted fabric as the final product are excellent.

In the present invention, the yarn physical properties were evaluated as follows.

Strength / Elongation / Modulus : The average value is obtained by measuring 50 times (Instrument Length: 5cm, Tensile Speed: 30cm / min) with Instron Company's tensile tester. Here modulus means initial modulus.

Density (ρ) : The island-in-the-sea composite fiber is introduced into a density meter composed of a mixed solvent of normal heptane and carbon tetrachloride (Shibayama, Japan, Model SS). Measure

Crystallinity [Xc (%)] : Based on the above density (ρ) value, the theoretical density of the complete crystal region of polyester (ρ _c = 1.457 g / cm 3) and the density value of the complete amorphous region (1.336 g / Using cm 3)

It was measured by: (JENAPOL -U INTERPHAKO German company Carl Zeiss product, model), birefringence (Δn) interference microscope. The birefringence is calculated by the formula below.

Where R is the compensator retardation, S is the retardation of quartz shim, and D is the fiber diameter. In addition, the units of R and S are nm and the units of D are μm.

Crystal orientation (Fc) : The half width of the peak (FWHM, which shows the characteristics of crystal orientation by performing azimuthal scanning on the (010) and (100) planes of the crystal by using an X-ray diffractometer) The crystal orientation (Fc) of the island components was calculated by measuring the full width at half-maximum intensity. However, since the sea component is completely amorphous, all peaks resulting from the azimuth scan are regarded as peaks due to the crystal plane of the island component. The equation for calculating the crystal orientation (Fc) from the full width (FWHM) is as follows.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited only to the following examples.

Example 1

An alkali-soluble polymer is prepared by blending 8% by weight of polyethylene glycol having a number average molecular weight of 8,500 to a copolymerized polyester having 4 mol% of dimethylisophthalatesulfonate sodium copolymerized. Using the prepared alkali-soluble polymer as a sea component, and polyethylene terephthalate having an intrinsic viscosity of 0.65 as a island component, they are spun through a island-in-the-sea composite spinneret having 36 island components at 288 ° C. The spun yarn was then drawn between a first high roller at 80 ° C. with a speed of 1,500 m / min and a second high roller at 125 ° C. with a speed of 4,200 m / min, and then wound at a winding speed of 4,300 m / min. A sea island type composite fiber of 75 denier 24 filaments is prepared. At this time, the manufacturing conditions were set such that the birefringence of the yarn under detention was 0.0009, the yarn modulus on the first high roller was 18.1 g / d, and the crystallinity on the second high roller was 33.24%. The islands-in-sea composite fiber prepared in this way was treated with island-in-sea composite fiber for 30 minutes in a 1% NaOH solution at 95 ° C. to elute the sea component, and then the raw material properties after sea component elution were evaluated by the method described above. Same as 2.

Example 2-Example 3 and Comparative Example 1-Comparative Example 2

The island-like composite fibers of 75 denier 24 filaments were manufactured under the same process and conditions as in Example 1 except that the manufacturing conditions such as the first high roller speed were changed as shown in Table 1. The islands-in-sea composite fiber prepared in this way was treated with island-in-sea composite fiber in 95% 1% NaOH solution for 30 minutes to elute the sea component, and then the raw material properties were evaluated by the method described above. Same as 2.

Manufacture conditions division 1st high roller speed (m / min) Second high roller speed (m / min) Yarn birefringence directly under detention Sensitive Yarn Modulus (g / d) Phase 2 crystallization phase yarn crystallinity (%) Example 1 1,500 4,300 0.00090 18.1 33.24 Example 2 1600 4,100 0.0004 17.6 33.63 Example 3 3,000 5,450 0.00098 22.3 40.56 Comparative Example 1 3000 6,000 0.0011 36.2 46.31 Comparative Example 2 800 4,000 0.00089 18.7 23.71

Yarn property evaluation result division Yarn Properties after Sea-Component Elution Elongation (%) Strength (g / d) Modulus (g / d) Crystal orientation (Fc) Example 1 47.23 3.71 36.47 0.8683 Example 2 45.72 3.84 34.28 0.8366 Example 3 49.37 3.56 38.29 0.8895 Comparative Example 1 23.8 1.24 17.98 0.9507 Comparative Example 2 36.4 1.38 20.37 0.7704

The island-in-the-sea island composite fiber for warp knitting produced by the method of the present invention minimizes damage to yarn physical properties in seawater dissolution and raising processes. As a result, it is excellent in brushing when manufacturing the warp knitted paper, it is possible to manufacture a warp knitted paper with excellent feel and appearance. Due to this effect, the island-in-the-sea composite fiber produced by the method of the present invention is particularly useful for producing brushed warp knits.

Claims (5)

In the process of producing 50 ~ 90 denier warp island-in-the-sea composite fiber using alkali-soluble copolyester as sea component and ordinary polyester as island component, it satisfies the following conditions simultaneously. Method for producing a island-in-the-sea composite fiber for warp knitting. -Below- Speed of the first high roller (V ₁ ): 1,000 m / min to 3,000 m / min Speed of the second high roller (V ₂ ): 4,000m / min to 6,000m / min Yarn modulus on the first high roller ≤ 20 g / d Yarn crystallinity on the second high roller: 25 to 45% The method for producing warp island-in-the-sea composite fiber according to claim 1, wherein the single yarn fineness before sea component elution is 2 to 4 denier and the single yarn fineness after sea component elution is 0.001 to 0.3 denier. The method for producing warp island-in-the-sea composite fiber according to claim 1, wherein the yarn crystal orientation (Fc) after dissolution of the sea component is 0.80 to 0.95. The method for producing warp island-in-the-sea composite fiber according to claim 1, wherein the yarn birefringence (Δn) under the detention is 0.001 or less. The method for producing warp island-in-the-sea composite fiber according to claim 1, wherein the first high roller has a speed V ₁ of 2,000 m / min to 3,000 m / min.