KR101426208B1 - Polyurethaneurea elastic fiber with high uniformity and excellent heat settable property - Google Patents

Abstract

The present invention relates to a polyurethaneurea elastic fiber produced by the steps of: 1) producing pre-polymer by using a composition including 2 to 25 mol% of 2,4′ diphenylmethane diisocyanate with respect to total weight of diisocyanate; 2) adding a chain extender to the pre-polymer to 3) obtain polyurethaneurea polymer having 40 mol% or more of a solidity content; ripening and spinning a polyurethaneurea spinning solution obtained by stirring the polyurethaneurea polymer. Since a polyurethaneurea elastic fiber produced by the steps has excellent uniformity and heat settable properties, and union cloth/knitted fabric using the elastic fiber has uniformity which is not deteriorated, a quality of the fabric is excellent, and since the elastic fiber is heat settable at low temperatures, thermal embrittlement of a relative fabric is prevented, thereby presenting excellent effects in yellowing and touch of the union cloth/knitted fabrics.

Description

[0001] The present invention relates to a polyurethaneurea elastic fiber having excellent uniformity and heat setting property,

The present invention relates to a polyurethane-urea elastic yarn excellent in uniformity and heat setting property. More specifically, in the preparation of a polyurethane prepolymer, 2 to 25 mol% of 2,4'-diphenylmethane diisocyanate is mixed with at least one diisocyanate containing 4,4'-diphenylmethane diisocyanate as a diisocyanate And the solid content of the final polyurethane-urea polymer is at least 40% by weight based on the total weight of the polyurethane-urea elastomer.

The polyurethaneurea is generally prepared by reacting a polyol with an excess of a diisocyanate compound to obtain a prepolymer having isocyanate groups at both ends of the polyol and a prepolymer obtained by dissolving the prepolymer in an appropriate solvent, A diamine-based or diol-based chain extender is added and a chain terminating agent such as a monoalcohol or a monoamine is reacted to prepare a spinning solution of a polyurethane-urea fiber, followed by drying and wet spinning to obtain a polyurethane- .

Such polyurethane-urea elastic yarns are used for various purposes due to their inherent properties with excellent elasticity and elastic restoring force, and as the range of use thereof is expanded, new additional characteristics are continuously required in existing fibers.

Generally, the polyurethane-urea elastic yarn is thermally hardened by heat treatment for setting in post-processing after knitting with thermosensitive mating yarn (nylon, silk, cotton, etc.) And the like. To solve these problems, the demand for polyurethane-urea elastic yarn which can be thermally set at a low temperature has increased, and the elastic yarn manufacturer has continuously made efforts to improve the heat set property of the polyurethane-urea elastic yarn.

For example, U.S. Patent No. 5,948,875 discloses a method for improving heat settability of a polyurethane-urea elastic yarn by using 50 mol% or more of 2-methyl-1,5-pentanediamine as a chain extender, 6,472,494 discloses a method of improving the heat setting property of a polyurethane-urea elastic yarn by applying a mixed amount of 2,4'-diphenylmethane diisocyanate in an amount of 23 to 55 mol%. In domestic patent No. 0,942,359, , 2'-25 mol% of 4'-diphenylmethane diisocyanate is mixed and 1,2-diaminopropane is used as an auxiliary chain extender to improve thermal settability. However, the techniques disclosed by the above patents are disadvantageous in terms of radiation workability due to decrease in heat resistance, insufficient modulus and elastic recovery rate due to decrease in retention during spinning and increase in magnetic flux, and yarn uniformity is insufficient, There is a disadvantage that the quality of the fabric is poor.

That is to say, the technology for producing polyurethane-urea elastic yarn having excellent uniformity and heat set property has not yet been completely established.

According to a preferred embodiment of the present invention, there is provided a polyurethane-urea elastic yarn comprising a polyol and a diisocyanate polymer,

1) A prepolymer is prepared by using a mixture containing 2 to 25 mol% of 2,4'-diphenylmethane diisocyanate based on the total weight of the diisocyanate,

2) adding a chain extender to the prepolymer to obtain a polyurethaneurea polymer,

3) A polyurethane-urea elastic yarn excellent in uniformity and heat set property, characterized in that a polyurethane-urea spinning solution having a solid content of 40 wt% or more of the final polyurethane-urea polymer is prepared and then spun.

According to another preferred embodiment of the present invention, the content of the first diisocyanate is 75 to 98 mol% and the content of the second diisocyanate is 2 to 25 mol%, wherein the second diisocyanate is 2,4'- Is characterized by using diphenylmethane diisocyanate. The 2,4'-diphenylmethane diisocyanate has a three-dimensional structure compared to the conventional 4,4'-diphenylmethane diisocyanate, so that the intermolecular hydrogen bonding force and the intramolecular hydrogen bonding force of the hard segment are weakened due to steric hindrance, The same effect as that of the increased content is exhibited, and the heat setting property of the yarn is improved.

According to another preferred embodiment of the present invention, the solid content of the final polyurethane-urea polymer is at least 40% by weight. When the solid content is 40% by weight or more, the deviation between the drying speed of the yarn surface during spinning and the solvent diffusion speed between the yarn inner-surface is reduced, the cross-section of the yarn becomes closer to the circular shape, The uniformity of the yarn is improved as the cross-sectional profile is closer to 1.0.

The polyurethane-urea elastic yarn according to the present invention is characterized in that the cross-sectional variance of the yarn is 1.20 or less, the uster% is less than 1.0, and the Heat Set Efficiency (HSE) is 50% or more after 170 캜 of dry heat.

The present invention provides a polyurethane-urea elastic yarn excellent in uniformity and heat setting property, which is excellent in the quality of the fabric without lowering the uniformity and can be thermally set at a low temperature to prevent thermal embrittlement of the counter yarn, The yellowing and the touch of the coloring agent exhibit excellent effects.

Hereinafter, the polyurethane-urea elastic yarn of the present invention will be described in more detail. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, to include an element throughout the specification does not exclude other elements unless specifically stated otherwise, but may include other elements.

The elastic yarn according to the embodiment of the present invention is produced by polymerizing a polyol to an excessive diisocyanate to obtain a prepolymer, dissolving the prepolymer in an organic solvent, adding a chain extender and a chain terminator to the solution, A spinning stock solution is prepared. At this time, the chain extender and the chain terminator may be added all at once or may be added in two or more stages.

Specific examples of the diisocyanate used in the production of the polyurethaneurea elastic yarn in the present invention include 4,4'-diphenylmethane diisocyanate, 1,5'-naphthalene diisocyanate, 1,4'-phenylene diisocyanate, hexamethylene di Diisocyanate, 1,4'-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, or isophorone diisocyanate. Of these diisocyanates, those containing 4,4'-diphenylmethane diisocyanate One or more diisocyanates are mixed with 2,4'-diphenylmethane diisocyanate. The content of 2,4'-diphenylmethane diisocyanate is suitably 2 to 25 mol%.

The 2,4'-diphenylmethane diisocyanate has a three-dimensional structure compared to the conventional 4,4'-diphenylmethane diisocyanate, so that the intermolecular hydrogen bonding force and the intramolecular hydrogen bonding force of the hard segment are weakened due to steric hindrance, The same effect as that of the increased content is exhibited, and the heat setting property of the yarn is improved.

If the content of 2,4'-diphenylmethane diisocyanate is less than 2 mol%, the effect of improving thermosetting property is insufficient. When the content of 2,4'-diphenylmethane diisocyanate is more than 25 mol%, the yarn modulus is rapidly lowered. The content of 4'-diphenylmethane diisocyanate is preferably within the above range.

The polymer diol used in the present invention is a copolymer of polytetramethylene ether glycol, polytrimethylene ether glycol, polypropylene glycol, polycarbonate diol, a mixture of alkylene oxide and lactone monomer and poly (tetramethylene ether) glycol, 3- A copolymer of methyl-tetrahydrofuran and tetrahydrofuran, or a mixture of two or more thereof, but is not limited thereto.

In the present invention, the weight ratio of the isocyanate of the prepolymer is preferably 1.7 to 4.1% in order to exhibit proper physical properties as a polyurethane-urea elastic yarn. If the weight ratio of isocyanate in the prepolymer is less than 1.7% or exceeds 4.1%, serious degradation of the physical properties of the elastic yarn is caused.

Examples of the chain extender include diamines such as ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 2,3-diaminobutane, 5-diaminopentane, 1,6-hexamethylenediamine and 1,4-cyclohexanediamine, or a mixture of two or more thereof.

As the chain terminator of polyurethaneurea, amines having one functional group such as diethylamine, monoethanolamine, dimethylamine and the like can be used.

And the solid content of the final polyurethane urea polymer is 40% by weight or more. When the solid content is more than 40% by weight, the content of the solvent relative to the solid content is lowered, so that the deviation between the solvent diffusion speed between the inside and the surface of the yarn is reduced compared to the solvent drying rate of the yarn surface during spinning, And the cross-sectional heterogeneity value is close to 1.0. The elasticity yarn has a uniform circular cross section as the cross-sectional deviation value is closer to 1.0, and the uster% is improved. When such knitting and knitting fabrics are knitted and processed by using such elastic yarns, the quality of the fabric is improved.

Further, in the present invention, in order to prevent discoloration and deterioration of physical properties of polyurethane-urea by a heat treatment process accompanying ultraviolet rays, atmospheric smog and spandex processing, it is preferable to add a stereogenic phenolic compound, a benzofuran- Based compound, a benzotriazole-based compound, a polymeric tertiary amine stabilizer, and the like.

Further, the polyurethane-urea elastic yarn of the present invention may contain additives such as titanium dioxide, magnesium stearate and the like in addition to the above components.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited thereto.

The NCO% measurement method of the polymer mentioned in the following Examples and Comparative Examples and the physical properties of the polyurethane-urea elastic yarn were measured as follows.

NCO % Measurement method

NCO% = [100 x 2 x NCO chemical formula x (capping ratio -1)] / {(diisocyanate molecular weight x capping ratio) + polyol molecular weight}

In the above formula, the capping ratio is the diisocyanate mole ratio / polyol mole ratio.

Strength and elongation of yarn

Measurement is made at a sample length of 10 cm and a tensile speed of 100 cm / min using an automatic power measuring device (MEL, Textechno). At this time, the strength and elongation at break are measured, and the load (200% modulus) applied to the yarn at 200% elongation is also measured.

Yarn Cross section

The length of the yarn is cut perpendicular to the longitudinal direction, and the W and H lengths are measured with a microscope on the cross section, and the ratio is calculated. The closer to 1.0, the more uniform the cross section is.

Sectional Deformity = W / H

(W: longest straight line length crossing the yarn cross-section

H: length of the shortest straight line perpendicularly intersecting with the longest straight line (W) traversing the yarn section)

U% of yarn

Using a Uster% measuring device (KET-QT), measure the speed of the feeding roller by setting the speed of the yarn de (20d is 30m / min) according to de. The sensor automatically reads the thickness of the yarn that has been marginalized for 20 seconds at a constant speed, calculates the average value, and draws a 0% reference line. If the thickness of the yarn read by the sensor per unit time is larger than 0%, the point is drawn in the (+) area compared to the 0% reference line. If the thickness is thinner, It is drawn. 0% The deviation from the standard line is calculated as an area to indicate U%. The smaller the value, the better the uniformity of the yarn.

U% = 0% Area outside the reference line / 0% Reference area under the line ⅹ 100

Yarn Heat Set Sex

The initial yarn L0 is stretched 100% in a state exposed to the atmosphere, followed by a heat treatment at 170 ° C for 1 minute. After cooling to room temperature, the yarn length (L2) is measured. The dry heat treated yarn is subjected to a wet heat treatment at 100 DEG C for 30 minutes in a relaxed state and dried at room temperature to measure a yarn length L3 (where L0, L1, L2 and L3 are the lengths of the yarns after each process Quot;).

 The dry heat treated yarn was subjected to wet heat treatment at 100 ° C for 30 minutes in a relaxed state, and then dried at room temperature to adjust the yarn length

Dry heat setting property (%) = {(L2-L0) / (L1-L0)} x 100

HSE (%) = {(L3-L0) / (L1-L0)} 100

Example  One

A capping ratio (CR) of 1.80, a content of 95 mol% of 4,4'-diphenylmethane diisocyanate and 5 mol% of 2,4'-diphenylmethane diisocyanate. Ethylene diamine and 1,2-diaminopropane were used in a ratio of 80 mol% and 20 mol%, and diethylamine was used as a chain terminator. The ratio of the chain extender and the chain terminator was 10: 1, and the amine used was adjusted to a total concentration of 7 mol%. As the solvent, dimethylacetamide was used to prepare a polyurethane having a solid content of 45 wt% Urea spinning solution was obtained.

The fiber stock solution obtained above was dry-spun at a speed of 900 m / min to prepare a 20 denier 1 filament polyurethane-urea elastic yarn. The properties of the yarn were evaluated and are shown in Table 1.

Example  2

The procedure of Example 1 was repeated except that 85 mol% of 4,4'-diphenylmethane diisocyanate and 15 mol% of 2,4'-diphenylmethane diisocyanate were used to prepare a polyurethaneurea elastic yarn And their physical properties were evaluated and shown in Table 1.

Example  3

The procedure of Example 1 was repeated except that 75 mol% of 4,4'-diphenylmethane diisocyanate and 25 mol% of 2,4'-diphenylmethane diisocyanate were used to prepare a polyurethaneurea elastic yarn And their physical properties were evaluated and shown in Table 1.

Example  4

The procedure of Example 1 was repeated except that 70 mol% of 4,4'-diphenylmethane diisocyanate and 30 mol% of 2,4'-diphenylmethane diisocyanate were used to prepare a polyurethaneurea elastic yarn And their physical properties were evaluated and shown in Table 1.

Comparative Example  One

A polyurethane-urea elastic yarn was prepared in the same manner as in Example 3 except that the solid content of the final polymer was 35% by weight, and physical properties thereof were evaluated.

Comparative Example  2

The polyurethaneurea elastic yarn was prepared in the same manner as in Example 1 except that 100 mol% of 4,4'-diphenylmethane diisocyanate was used. The properties of the polyurethaneurea elastic yarn were evaluated and are shown in Table 1.

As shown in Table 1 above, when 2,4'-diphenylmethane diisocyanate is used in an amount of 25 mol% or more, it can be confirmed that the homogeneity and heat set property are excellent but the 200% modulus is lowered. When the solid content of the final polymerized product is less than 40% by weight even when 2 to 25 mol% of the final polymerized 2,4'-diphenylmethane diisocyanate is used, it can be confirmed that the thermosetting property is excellent, but the cross- .

Although the preferred embodiments of the present invention have been described in detail to some extent, it is natural that various modifications can be made to them. It is therefore to be understood that the invention may be practiced otherwise than as specifically described herein without departing from the scope and spirit of the invention.

Claims (4)

Polyurethane Urea elastic yarn having a cross-sectional profile of 1.20 or less and HSE of 50% or more according to the following measurement method.
1) Cross-sectional heterogeneity measurement method: Polyurethane urea elastic fiber is cut perpendicularly to the longitudinal direction, and the W and H lengths of the cross section are measured with a microscope and the ratio is calculated. As the cross-sectional variance value approaches 1.0, the cross section of the elastic yarn is close to the circular shape and the uniformity is excellent.
Sectional Deformity = W / H
(W: longest straight line length crossing the yarn cross-section
H: length of the shortest straight line perpendicularly intersecting with the longest straight line (W) traversing the yarn section)

2) HSE measurement method: The initial yarn (L0) is subjected to 100% elongation (L1) with exposed to the atmosphere, followed by a heat treatment at 170 ° C for 1 minute, followed by cooling to room temperature and then measuring the yarn length (L2). The dry heat treated yarn is heat treated in a relaxed state at 100 ° C for 30 minutes and dried at room temperature to measure the yarn length (L3).
HSE (%) = {(L3-L0) / (L1-L0)} 100 In producing the polyurethane-urea elastic yarn of claim 1,
Wherein the 2,4'-diphenylmethane diisocyanate is contained in an amount of 2 to 25 mol% based on the total weight of the diisocyanate. In producing the polyurethane-urea elastic yarn of claim 1,
Characterized in that the solids content of the polymerizate immediately before passing through the spinneret is at least 40% by weight. In producing the polyurethane-urea elastic yarn of claim 1,
Wherein the NCO% at the time of the first polymerization of the polyol and the diisocyanate is in the range of 1.7 to 4.1%.