KR100587903B1 - A polyurethane elastic fiber, and a process of preparing the same - Google Patents

Abstract

The present invention relates to a polyurethane elastic fiber having a low heat shrinkage and a process for producing the same.

The present invention relates to a process for producing a polyurethane elastic fiber in the order of spinning, false twisting and winding process, wherein a heat treatment device (14) is provided under the spinning process to heat the spun elastic fiber to obtain a boiling water shrinkage ratio of 7% , And a polyurethane elastic fiber having a heat shrinkage of 5% or less after being treated in a hot air oven at 100 캜 for 1 hour is produced.

The polyurethane elastic fiber of the present invention is used for manufacturing high quality sports clothing.

Heat shrinkage, polyurethane, elastic fiber, heat treatment, heating tube, boiling water shrinkage

Description

TECHNICAL FIELD [0001] The present invention relates to a polyurethane elastic fiber and a process for preparing the same,             

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view of a conventional process for producing polyurethane elastic fibers. Fig.

2 is a schematic view of the process of the present invention for producing polyurethane elastic fibers.

[0001] Description of the Related Art [0002]

1: spinning stock solution 2: gear pump 3: hot gas inlet

4: spinneret 5: radiation tube 6: cemented point

7: gas outlet 8: gas inlet 9: false twisting unit

10, 12: Godet roller 11: Emulsion treatment roller

13: Winder 14: Heat treatment device 15: Temperature supply and controller

The present invention relates to a polyurethane elastic fiber having a low heat shrinkage and a process for producing the same.

Polyurethane elastomeric fibers are produced by predominantly dry spinning of polyurethane polymers.

The polyurethane polymer is prepared by first preliminarily polymerizing a high molecular weight polyol (diol compound) and an excess amount of a diisocyanate compound to prepare a prepolymer in one step, and then adding a chain extender such as a diol or a diamine compound thereto to prepare 2 Stage chain extension and chain termination reaction.

More specifically, the one-step prepolymerization is a step of forming a urethane bond by reacting a high molecular weight diol compound, a polyol, with an excess of a diisocyanate, and forming a prepolymer having isocyanate groups at both ends of the polyol.

The prepolymer has a hard segment content of 15-30%. Generally, the molecular weight of the polyol is about 2,000 g / mole, and the polymerization proceeds at a value close to 2 in the NCO / OH ratio. The prepolymerization is usually carried out in a solvent-free, bulky state at about 60 to 90 DEG C for 1 to 2 hours.

The higher the reaction temperature, the faster the reaction rate. When a solvent such as dimethylacetamide (hereinafter referred to as "DMAc") or dimethylformamide (hereinafter referred to as "DMF") is used, the reaction rate is increased by the catalytic action of the solvent The reaction is completed at 30 to 60 ° C within 10 to 20 minutes.

The two-step chain extension reaction is a reaction for increasing the degree of polymerization by reacting a prepolymer with a compound having a low molecular weight active hydrogen such as ethylenediamine, propylenediamine, 1,4-butanediol, etc. as a chain extender.

When reacted with a diamine, a urea bond is formed, and when it is reacted with a diol, a urea bond is formed. Since the chain extension reaction is an exothermic reaction which is different from the prepolymerization, the solution polymerization is carried out using a polar solvent such as DMAc or DMF for a uniform reaction.

In particular, when the diamine is used as a chain extender, the reaction rate is extremely high. Therefore, to maintain uniform reaction conditions, the reaction is carried out at a low temperature of 0 to 15 ° C. and the chain extender is slowly added throughout the reaction. A small amount of monoamine is used in the chain extension reaction to control the reaction rate and reactivity.

Conventionally, the polyurethane elastic fibers have been produced by dry-spinning the polymerized polyurethane polymer solution (hereinafter referred to as "spinning stock solution") in the process of Fig.

Specifically, the spinning stock solution 1 subjected to defoaming and filtration is discharged into the spinning tube 5 through the spinneret 4 using the gear pump 2. At the same time, the hot gas is introduced into the radiation tube 5 through the hot gas inlet 3 located above the radiation tube 5.

As a result, the solvent in the discharged filament is evaporated and diffused by the hot gas, and the filament is solidified and refined. The hot gas containing the solvent is discharged to the outside of the radiation tube 5 through the gas outlet 7 located at the lower end of the radiation tube 5.

The filament that has passed through the radiation tube 5 is then subjected to a false twist in the false twisting unit 9. As a result, the filaments are fused to each other at a certain point (hereinafter referred to as "cementing point 6") in the radiation tube 5 to be in the form of monofilaments.

By such a burning treatment, it is possible to prevent embossing in a post-process. The filaments passing through the combustor 9 are wound around the godet rollers 10 and 12 and the emulsion treatment rollers 11 to the take-up machine 13.

The polyurethane elastic fibers produced by the conventional dry spinning method as described above have a problem that they are shrunk too much by the boiling water treatment and the heat treatment which are applied in post-processes such as dyeing and processing. Excessive shrinkage during boiling water treatment and heat treatment not only lowers post-processability but also lowers the quality of the final processed knitted fabric.

In order to solve such a problem, the temperature inside the spinning tube 5 and the temperature of the combustor 9 in the conventional dry spinning (the process of FIG. 1) are appropriately adjusted or the temperature of the godet rollers 10, 12 and the winder 13 ). However, the problem of too much shrinkage of the polyurethane elastic fibers due to boiling water treatment and heat treatment could not be solved.

An object of the present invention is to provide a polyurethane elastic fiber having a low heat shrinkage, that is, a thermally stabilized thermal property, in order to improve the post-processability and the quality of the processed fabric.

Disclosed is a polyurethane elastic fiber having a stable thermal property and a low shrinkage ratio during boiling water treatment or heat treatment, and a process for producing the same.

The present invention relates to a polyurethane elastic fiber having a low shrinkage ratio during boiling water treatment or heat treatment, and a process for producing the same.

More specifically, the present invention relates to a polyurethane elastic fiber characterized by a boiling water shrinkage of 7% or less and a heat shrinkage of 5% or less after being treated in a hot air oven at 100 캜 for 1 hour.

The present invention also provides a method for producing polyurethane elastic fibers in the order of spinning, false twisting and winding, wherein a heat treatment device (14) is provided under the above-mentioned emulsification step to heat- To a method for producing elastic fibers.

Hereinafter, the present invention will be described in detail.

First, the present invention provides a prepolymer having an isocyanate group at both ends of a polyol by reacting a high molecular weight diol compound (polyol) with an excessive amount of a diisocyanate compound.

At this time, it is preferable to use polytetramethylene glycol (PTMG) as the high molecular weight diol compound and 4,4'-diphenylmethane diisocyanate as the diisocyanate compound.

Next, the addition of organic solvents such as dimethylacetamide (DM _AC) or dimethylformamide (DMF) to the prepolymer to prepare a prepolymer solution.

Subsequently, a diamine compound such as ethylenediamine is added to the prepolymer as a chain extender to improve the degree of polymerization of the prepolymer. At this time, in order to maintain uniform reaction conditions, it is preferable that the chain extender is gradually added over the entire reaction period while maintaining the temperature at 0 to 15 ° C.

The polyurethane polymer solution (spinning solution) thus polymerized is dry-spun by the process of Fig. 2 to produce the polyurethane elastic fiber of the present invention. 2 is a schematic process drawing of the present invention.

Specifically, the spinning stock solution 1 subjected to defoaming and filtration is discharged into the spinning tube 5 through the spinneret 4 using the gear pump 2. At the same time, the hot gas is introduced into the radiation tube 5 through the hot gas inlet 3 located above the radiation tube 5.

As a result, the solvent in the discharged filament is evaporated and diffused by the hot gas, and the filament is solidified and refined. The hot gas containing the solvent is discharged to the outside of the radiation tube 5 through the gas outlet 7 located at the lower end of the radiation tube 5.

The filament that has passed through the radiation tube 5 is then subjected to a false twist in the false twisting unit 9. As a result, the filaments are fused to each other at a certain point (hereinafter referred to as "cementing point 6") in the radiation tube 5 to be in the form of monofilaments. By such a burning treatment, it is possible to prevent embossing in a post-process.

The filament that has passed through the false twister 9 is heat-treated at a temperature of 100 ° C or higher in the heat treatment apparatus 14 and wound around the winding machine 13 via the godet rollers 10 and 12 and the emulsion treatment roller 11 .

The present invention is characterized in that the irradiated filament is heat-treated in a heat treatment apparatus (14). The heat treatment apparatus 14 is installed under the spinning process, and it is more preferable to install it between the flammable process and the winding process.

The heat treatment temperature in the heat treatment apparatus 14 is 100 DEG C or higher, more preferably 100 to 150 DEG C. If the heat treatment temperature is lower than the above range, the thermal stability of the filament deteriorates and heat shrinkage is caused by boiling water treatment and heat treatment. If the heat treatment temperature is higher than the above range, the properties of the filament deteriorate.

The time (heat treatment time) during which the filament passes through the heat treatment apparatus 14 is preferably 0.01 to 0.05 seconds. The heat treatment time can be adjusted by the rotation speed of the godet rollers 10 and 12. As the heat treatment apparatus 14, a heating tube or a heating roll is used.

The heating tube is provided with a temperature controller and a controller 15. The inner wall of the heating tube through which the filament passes is Teflon coated to prevent filament fusion. The length of the heating tube is preferably 20 to 30 cm.

This heat treatment process is intended to prevent the instability of the structure that occurs when the filament passing through the high-temperature radiation tube 5 is cooled to room temperature. In other words, the structure of the filament is stabilized by the heat treatment process, and the shrinkage ratio of the filament during heat treatment is lowered.

The polyurethane elastic fiber produced by the method of the present invention has a boiling water shrinkage of 7% or less and a heat shrinkage of 5% or less after treatment in a hot air oven at 100 캜. Generally, the polyurethane elastic fibers produced by the method of the present invention have a boiling water shrinkage of 5 to 7% and a heat shrinkage after treatment in a hot air oven at 100 캜 of 3 to 5%. As a result, the polyurethane elastic fiber of the present invention improves the post-processability such as dyeing, processing and the like, and also improves the quality of the final processed paper.

In the present invention, boiling water shrinkage ratio and heat treatment shrinkage ratio are evaluated as follows.

· Boiling water shrinkage (%)

The polyurethane elastic fibers are immersed in boiling water for 15 minutes, then left at room temperature for 1 hour, and the fiber length before and after treatment is substituted into the following equation to determine boiling water shrinkage.

× 100Boiling water shrinkage (%) =

× 100

Heat shrinkage (%)

Heat the polyurethane elastic fibers in a hot air oven at 100 ° C for 1 hour, then stand at room temperature for 1 hour, and calculate the heat shrinkage ratio by substituting the fiber length before and after treatment into the following formula.

× 100Heat shrinkage (%) =

× 100

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

Example 1

1 mole of polytetramethylene glycol having a molecular weight of 2,200 and 2 moles of 4,4'-diphenylmethane diisocyanate were mixed and reacted at 90 DEG C for 90 minutes to synthesize a prepolymer having isocyanate groups at both ends.

This prepolymer is cooled to 40 占 폚 and N, N'-dimethylacetamide is added to prepare a solution containing about 45% of the prepolymer. While the prepolymer solution was lowered to 5 캜 and vigorously stirred, N, N'-dimethylacetamide solution containing 96 equivalent% of ethylenediamine and 6 equivalent% of diethylamine was slowly added to the prepolymer while the prepolymer was stirred Chain extension to prepare a spinning stock solution.

The spinning stock solution 1 is defoamed and filtered, and is discharged into the spinning tube 5 through the spinneret 4 using the gear pump 2. At the same time, the hot gas is introduced into the radiation tube 5 through the hot gas inlet 3. The introduced high temperature gas evaporates the organic solvent in the filament and discharges it out of the radiation tube 5 through the gas outlet 7 in a state containing it.

Then, the filament passing through the radiation tube 5 is subjected to a burning treatment with a combustor 9, followed by heat treatment in a heating tube at 100 ° C for 0.05 second. The length of the heating tube is 25 cm.

The heat-treated filaments are passed through the godet rollers (10, 12) and the emulsion treatment rollers (11), and then wound on a winder (13) to produce polyurethane elastic fibers. Table 2 shows the results of evaluating boiling water shrinkage ratio and heat treatment shrinkage ratio of the produced elastic fibers.

Examples 2 to 7 and Comparative Example 1

Polyurethane elastic fibers were produced under the same process and conditions as in Example 1 except that the kind of heat treatment apparatus 14, the heat treatment temperature and the heat treatment time were changed as shown in Table 1. Table 2 shows the results of evaluating boiling water shrinkage ratio and heat treatment shrinkage ratio of the produced elastic fibers.

<Table 1> Manufacturing conditions

division Type of heat treatment equipment Heat treatment temperature (캜) Heat treatment time (sec) Example 1 Heating tube 100 0.05 Example 2 Heating tube 110 0.04 Example 3 Heating tube 120 0.03 Example 4 Heating tube 130 0.02 Example 5 Heating tube 140 0.01 Example 6 Heating tube 150 0.01 Example 7 Heating roll 120 0.03 Comparative Example 1 No heat treatment device used 0 0

<Table 2> Fiber Property Evaluation Results

division Boiling water shrinkage (%) Shrinkage after hot air oven treatment (%) (heat shrinkage) Example 1 6.7 4.4 Example 2 6.4 4.4 Example 3 6.2 4.3 Example 4 5.9 4.0 Example 5 5.5 4.0 Example 6 5.3 3.8 Example 7 6.3 4.4 Comparative Example 1 15.0 16.0

The polyurethane elastic fiber of the present invention is excellent in thermal stability and has a low shrinkage ratio during boiling water treatment or heat treatment. As a result, post-processability such as dyeing and processing is improved, and the quality of the final processed paper is also improved.

Claims (9)

In producing polyurethane elastic fibers in the order of spinning, false twisting, heat treatment and winding, the twisted polyurethane elastic fibers are 20 to 30 cm in length, and the shape is selected from heating tubes and heating rolls Wherein the heat treatment is carried out for 0.01 to 0.05 seconds in a heat treatment apparatus (14) having a temperature of 100 占 폚 to 150 占 폚. delete delete delete delete delete Wherein the boiling water shrinkage is 7% or less, and the heat shrinkage after treatment in a hot air oven at 100 캜 for 1 hour is 5% or less. 7. The polyurethane elastic fiber according to claim 7, wherein boiling water shrinkage ratio is 5 to 7%. 7. The polyurethane elastic fiber according to claim 7, wherein the heat shrinkage after treatment in a hot air oven at 100 DEG C for 1 hour is 3 to 5%.

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