KR100537252B1 - Polyurethane fiber of good heat setting property and Process for the production of the same - Google Patents

Abstract

The present invention relates to a polyurethane elastic fiber having excellent thermosetability and a method for manufacturing the same, and more particularly, to a conventional polyurethane polymer, an appropriate amount of polystyrene-acrylonitrile copolymer (SAN) and thermoplastic polyurethane ( TPU) is a mixture of 1 to 30 parts by weight with respect to the weight of the conventional polyurethane polymer is spinning.

The polyurethane fiber according to the present invention has a heat setability of 65% or more at dry heat of 100 ° C. and a change rate of strength and elastic recovery rate of about 7% and 10%, respectively.

Description

Polyurethane fiber excellent in heat setability and its manufacturing method {Polyurethane fiber of good heat setting property and Process for the production of the same}

The present invention relates to a polyurethane fiber having excellent thermosetability and a method for manufacturing the same, and more particularly, to a mixture of a polystyrene-acrylonitrile copolymer (SAN) and a thermoplastic polyurethane (TPU) in a conventional polyurethane polymer. The present invention relates to a polyurethane fiber excellent in heat setability prepared by mixing in an appropriate ratio and a method for producing the same.

Polyurethane generally reacts with a polyol, a high molecular weight diol compound, and an excess of diisocyanate compound to obtain a prepolymer having an isocyanate group at the end of the polyol, and dissolving the prepolymer in a suitable solvent. Thereafter, the solution is prepared by a secondary polymerization reaction in which a diamine-based or diol-based chain extender is added and reacted.

Polyurethane fibers are generally dry spinning for evaporating and drying a solvent by a heating gas while extruding a spinning liquid containing polyurethane through a nozzle; Wet spinning which solidifies a polymer in fibrous form simultaneously with extrusion by extruding a spinning solution containing a polyurethane into an aqueous solution through a nozzle; A chemical spinning method in which a prepolymer solution having a terminal isocyanate group is extruded through a nozzle into a reaction solution containing an amine chain extender for chain extension reaction, or through a melt spinning method in which a polyurethane is extruded and cooled through a nozzle in a hot melt state. Are manufactured.

Polyurethane fibers prepared in this way can be used in combination with various other fibers such as acrylic, wool, cotton, silk, etc., depending on the application, in particular, an elastic fiber containing more than 85 parts by weight of the long chain soft segment is called spandex do.

Polyurethane fibers are actively used for various purposes because of their inherent characteristics with high elasticity, and as the range of their use expands, new additional properties continue to be required for existing polyurethane fibers.

Until now, a number of polyurethane fibers, which have been further strengthened in heat resistance and elastic recovery, have been developed, and in recent years, the demand for polyurethane fibers having high heat setability has gradually increased.

In response, efforts have been made to improve the thermosetability of polyurethane fibers.

For example, Japanese Patent Laid-Open Nos. 63-53287 and 63-53288 disclose thermoset properties of polyurethane elastic yarns using polyurethanes prepared by adding specific additives such as diisocyanate dimers or fine powder silica, respectively. A method of improving is disclosed.

However, these methods have problems such that it is difficult to uniformly disperse the additives in the polyurethane polymerization product, it is difficult to set appropriate mixing conditions, and the polymerization reaction itself becomes complicated.

Alternatively, Japanese Patent Publication No. 43-639 discloses a prepolymer having an hydroxyl group terminal and an isocyanate terminal by reacting a compound containing a diisocyanate group with a mixture of polymer diol and a low molecular weight diol of 1 to 3 moles of the polymer diol. After preparing a prepolymer having the polymer, a method of reacting both to obtain a polyurethane polymer is described.

However, the polyurethane obtained by this method has a limitation that it can be applied only to melt spinning.

In addition, Korean Patent Laid-Open Publication No. 2001-5854 is characterized in that the polyurethane polymer in the fluid state obtained by reacting both isocyanate terminal prepolymer and hydroxyl terminal prepolymer having relatively close viscosity to each other and then reacted with each other is continuously extruded through a nozzle. It describes a method for producing a polyurethane fiber.

According to this method, since the two prepolymers have similar viscosities, it is possible to uniformly mix each component in the secondary polymerization reaction, and to improve the stirring effect and the spinning stability. Compared to the manufacturing method of the process is not only very complicated, but also the improvement of the stirring effect and spinning stability can be made relatively easily through the operation of the process conditions, has the disadvantage that the practicality is not very large.

On the other hand, Japanese Patent Laid-Open No. 7-316922 proposes a relatively simple method to improve the heat setability of the polyurethane fiber, which is basically a polyurethane fiber produced by a conventional method, The alternative is to replace some of the urethane components with thermoplastic polyurethane.

The thermoplastic polyurethane is prepared by using diol instead of diamine as a chain extender in a secondary polymerization reaction in the process of preparing a conventional polyurethane polymer.

However, according to this method, the heat setability of the polyurethane elastic yarn is improved, but there are disadvantages in that elongation, which is a major feature of polyurethane fibers, is lowered and an unnecessary increase in modulus is caused.

In addition, a method of replacing a part of a polyurethane polymer prepared by a conventional method using a low molecular weight styrene maleic anhydride copolymer having a number average molecular weight of less than 5,000 is also described. It is not preferable when considering the aspect called basic physical property maintenance.

On the contrary, Korean Patent Publication No. 2001-16788 discloses a method for improving the heat setability of yarns by undergoing a separate heat treatment step after spinning in the process of producing polyurethane fibers by a general dry spinning method.

However, this method also requires additional equipment in addition to the existing spinning equipment, and by adding unnecessary heat to the yarn improves the heat setability of the yarn, but has the disadvantage of deteriorating the basic properties such as strength and elongation.

The present invention is to solve the problems of the prior art as described above, in the production of polyurethane fibers having excellent heat setability, the conventional polystyrene-acrylonitrile copolymer (SAN) and the polymer solution for polyurethane elastic yarn production By dissolving and mixing thermoplastic polyurethane (TPU) at an appropriate ratio, heat setability is greatly improved while having the same strength and elastic recovery rate as that of polyurethane elastic yarn produced in a conventional manner without changing the conventional production process conditions and equipment. An object of the present invention is to provide a polyurethane elastic yarn and a method of manufacturing the same.

In the present invention, a polystyrene-acrylonitrile copolymer having an acrylonitrile content of 10 to 50 parts by weight and a number average molecular weight of 10,000 to 1,000,000 and a thermoplastic polyurethane having a number average molecular weight of 1,000 to 100,000 are mixed in an appropriate ratio. The present invention relates to a method for producing a polyurethane fiber having excellent thermosetability, which is characterized in that it is spun by mixing a weight ratio of 1:99 to 30:70 to an existing polyurethane.

In addition, the present invention is a polyurethane fiber produced by the above method is 65% or more of heat setability at dry heat 160 ℃, while maintaining the strength and elastic recovery rate of the polyurethane fiber produced by the conventional method, the change in elastic recovery rate is small The present invention relates to a polyurethane fiber having excellent heat setability.

Hereinafter, the manufacturing method of the polyurethane fiber of this invention is demonstrated in detail.

Segmented polyurethanes used in the present invention are prepared by reacting organic diisocyanates with polymeric diols to produce polyurethane prepolymers, which are dissolved in organic solvents and then reacted with diamines and monoamines.

In the present invention, specific examples of the organic diisocyanate include 4.4'-diphenylmethane diisocyanate, 1,5'-niphthalene diisocyanate, 1,4'-phenylenedi isocyanate, hexamethylene diisocyanate, 1,4'-cyclo Hexane diisoyanate, 4,4'-dicyclohexyl methane diisocyanate, isophorone diisocyanate, or a mixture of two or more thereof.

Polymeric diols include polytetramethylene ether glycol, polypropylene glycol, polycarbonate diol, and the like.

Examples of diamines which are chain extenders include one or a mixture of two or more of ethylenediamine, 1,2'-propylenediamine, hexamethylenediamine, xylenediamine, 4,4'-diphenylmethanediamine, hydrazine, and the like. .

In the present invention, the content of acrylonitrile (AN) of the polystyrene-acrylonitrile copolymer (SAN) is 10 to 50 parts by weight.

If the content of acrylonitrile is less than 10 parts by weight, it is not compatible with thermoplastic polyurethane, which causes problems in workability during spinning. If the content of acrylonitrile is more than 50 parts by weight, solubility in solvents and The moldability becomes bad.

In addition, the polystyrene-acrylonitrile copolymer has a number average molecular weight of 10,000 to 1,000,000, and if it is less than 10,000, there is little heat set effect, and if it exceeds 1,000,000, dissolution and moldability are reduced.

In addition, the number average molecular weight of the thermoplastic polyurethane is 1,000 to 100,000, and low molecular weight of less than 1,000 has little effect of thermosetability. If the molecular weight exceeds 100,000, the thermoplastic polyurethane has no compatibility with polyacrylonitrile. Falls and seriously affects the basic physical properties of the yarn.

In the present invention, the mixing ratio of polystyrene-acrylonitrile copolymer to thermoplastic polyurethane is preferably 90:10 to 50:50 by weight.

If the thermoplastic polystyrene-acrylonitrile in the mixture exceeds 90 parts by weight, the elastic recovery rate of the final polyurethane fiber is lowered, and if the mixing ratio is less than 50 parts by weight, the thermosetability is lowered.

The physical properties of the polyurethane fiber according to the present invention are influenced by the type and mixing ratio of the polystyrene-acrylonitrile copolymer and thermoplastic polyurethane mixed as described above, and also the mixing ratio of these mixtures with existing polyurethanes It is also affected by.

If the mixing ratio of the polyacrylonitrile and the thermoplastic polyurethane mixture with respect to the existing polyurethane is less than 1 part by weight, there is little improvement in setability. If it exceeds 30 parts by weight, the basic properties of the yarn and the elastic recovery force are not good. Cause.

Therefore, if appropriately adjusted the mixing ratio of the appropriate polystyrene-acrylonitrile polymer and thermoplastic polyurethane with the existing polyurethane within the above-described range, both excellent heat setability and elastic recovery rate, and maintains the same basic physical properties as conventional polyurethane fibers Polyurethane fiber can be obtained.

In the present invention, the spinning method is not particularly limited, and existing dry spinning, wet spinning, and melt spinning methods except chemical spinning can be used as they are.

Hereinafter, the present invention will be described in more detail with reference to examples, but these examples are for illustrative purposes only and should not be construed as limiting the present invention.

The thermosetability and strength of the polyurethane fibers in the examples and the comparative examples were measured by the following method.

* Heat Settable

The stretched yarn was stretched 100%, and then heat-treated at 160 ° C. for 1 minute while exposed to the atmosphere.

Thereafter, after cooling to room temperature, the length of the yarn was measured, and heat setability of the yarn was calculated according to the following equation.

Heat Setability (%) = {(length after heat treatment-initial length) / (height length-initial length)} x 100

* burglar

Using Instron 5565, an Instron 5565, the yarn produced at 20 ° C. and 65% humidity was cut into 5 cm lengths, stretched at a constant speed of 500 mm / min, and the load value when the yarn was cut was measured.

* Elastic recovery rate

The yarn produced was cut into 5 cm lengths, and repeated 5 times of 0-300% repeated stretching at a speed of 500 mm / min, indicating the fifth specific load and modulus ratio of the load.

Elastic recovery rate (%) = {200% modulus of the fifth unloaded load / 200% modulus of the fifth load} x 100

Example 1

A polystyrene-acrylonitrile polymer having a number average molecular weight of 50,000 and a thermoplastic polyurethane having a number average molecular weight of 10,000 were mixed and used in a weight ratio of 70:30.

Polystyrene-acrylonitrile was completely dissolved in a dimethylacetamide (DMAC) solvent, and then thermoplastic polyurethane was added to prepare a mixed solution.

The mixture of polystyrene-acrylonitrile and thermoplastic polyurethane thus prepared is mixed in a weight ratio of 90:10 with respect to the polyurethane polymer prepared in a conventional manner to prepare a spinning solution, and then dry spinning is carried out using the spinning solution. It was.

The heat setability and basic physical properties (elastic recovery rate and strength) of the polyurethane fiber thus prepared are shown in Table 2 in comparison with the conventional polyurethane fiber (Creora, Hyosung Co., Ltd.).

Examples 2-4 and Comparative Examples 1-3

In the same manner as in Example 1, except that the mixing ratio (weight ratio) of the polystyrene-acrylonitrile polymer and the thermoplastic polyurethane with the polyurethaneurea polymer prepared in the conventional manner was changed as shown in Table 1. Polyurethane fibers were produced.

The heat setability and basic physical properties of the polyurethane fibers according to the examples and comparative examples are shown in Table 2 in comparison with the conventional polyurethane elastic yarn (Creora, Hyosung Co., Ltd.).

Table 1

SAN / TPU mix ratio (weight ratio) SAN (AN content) (parts by weight) SAN number average molecular weight TPU Number Average Molecular Weight Mixing ratio of SAN + TPU to conventional polyurethane (w / w) Example 1 70/30 25 50,000 10,000 10/90 Comparative Example 1 70/30 25 50,000 10,000 0.5 / 99.5 Comparative Example 2 70/30 25 50,000 10,000 40/60 Comparative Example 3 100/0 25 50,000 10,000 Example 2 90/10 25 50,000 10,000 10/90 Example 3 80/20 25 50,000 10,000 10/90 Example 4 50/50 25 50,000 10,000 10/90

* AN content: weight part content of acrylonitrile in SAN

TABLE 2

Heat Setability (%) burglar Elastic recovery Measured value (gf / d) % Change % Of measurement % Change Example 1 72 1.45 -3.3 77 -3 Comparative Example 1 45 1.48 -1.3 79 -One Comparative Example 2 80 1.32 -12 67 -13 Comparative Example 3 84 1.25 -16.7 62 -18 Example 2 75 1.43 -4.7 72 -8 Example 3 73 1.42 -5.3 73 -7 Example 4 68 1.47 -2 77 -3 Creora 43 1.5 0 80 0

As can be seen from Table 2, the polyurethane fiber according to the method of the present invention has a high heat setability of 65% or more and a high elastic recovery rate.

In addition, compared with the conventional polyurethane fiber, the polyurethane fiber according to the present invention has a rate of change of strength of less than 7% and a rate of change of elastic recovery rate of about 10%, which is very low compared to the conventional one.

As described in detail above, the polyurethane fiber produced by the present invention not only has excellent heat setability, but also has a very low change rate of strength and elastic recovery rate, which are basic physical properties, as compared to conventional polyurethane fibers, and thus excellent heat set. It can be used as a yarn for products that require elasticity and elastic recovery.

Claims (3)

In preparing the polyurethane fibers, the polystyrene-acrylonitrile copolymer (SAN) and the thermoplastic polyurethane (TPU) are mixed at a weight ratio of 90:10 to 50:50, and then the mixture and the existing polyurethane polymer Method of producing a polyurethane fiber having excellent heat setability, characterized in that the mixture in a weight ratio of 1:99 to 30:70 and then spun. The polystyrene-acrylonitrile (SAN) has an acrylonitrile content of 10 to 50 parts by weight, a number average molecular weight of 10,000 to 1,000,000, and a number average molecular weight of the thermoplastic polyurethane (TPU) of 1,000. Method for producing a polyurethane fiber having excellent heat setability, characterized in that from 100,000 to 100,000. Polyurethane fiber produced by the method of claim 1 having the following physical properties.           -Below- Heat setability at dry heat 160 ℃: 65% or more.