JPH03206123A - Polyurethane-polyamide-based conjugate fiber and production thereof - Google Patents

Abstract

PURPOSE:To provide the subject eccentric conjugate fiber composed of respectively specified elastic polyurethane component and polyamide component, excellent in stress recovery characteristics, heat resistance, especially fitness and transparency and useful as a material for a stocking and a tricot. CONSTITUTION:An objective fiber composed of (A) a polyurethane component consisting of an elastic polyurethane having 190-230 deg.C, preferably 195-220 deg.C DSC melt peak temperature and preferably >=150kgf/cm<2> tensile stress at 100% elongation and (B) a polyamide component (preferably having 200-300 deg.C melting point, e.g. nylon 6,6). In addition, the ratio of the hard segment of the component (A) to the soft segment thereof is preferably (20:80)-(25:75) in weight ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in self-crimping composite fibers made of polyurethane and polyamide. More specifically, the present invention relates to a polyurethane-polyamide composite fiber that has excellent recovery stress characteristics and heat resistance, and is particularly useful as a material for stockings and tricots that has excellent fit and transparency.

[Prior Art] A self-crimping composite fiber made by eccentrically compounding polyurethane and polycapramide can be made into a knitted fabric with excellent crimp properties and transparency, and is therefore highly valued as a material for high-grade stockings. It is evaluated.

The polyurethane components in this composite fiber include polyol, polyether made of polyalkylene oxide, polytetrahydrofuran, etc.; polylactone obtained by ring-opening polymerization of ε-cabrolactone; acids such as adipic acid and glutaric acid, and ethylene glycol, propylene Polyesters obtained by condensation polymerization with glycols such as glycols; or polyesters obtained by using polycarbonate esters, reacting these polyols with diisocyanates, and elongating the chain with low molecular weight diols, or hydrazine and ethylenediamines. Elastic polyurethanes are known.

Among these polyurethane compounds, it is possible to copolymerize or mix polycarbonate polyurethane, which has excellent peeling resistance with polyamide components and relatively excellent heat resistance, with other polyester polyurethanes, polyether polyurethanes, etc. It is said to be good (Tokuko Sho 55-2)
2570, Special Publication No. 57-34370, etc.)
.

[Problems to be Solved by the Invention] Even if eccentric composite fibers are manufactured using the conventional polyurethane component described above, it is possible to obtain a fairly excellent coil-like crimp, but in recent years there has been a particularly high demand for high fit in the stocking field. There is a growing demand for eccentric composite fibers made of polyurethane/polyamide that have strong elasticity and provide even better fit.

In addition, with conventional polyurethane/polyamide composite fibers,
Since the heat resistance of polyurethane is inferior to that of polyamide, troubles have also been observed in which the fit or durability of the product deteriorates due to heat treatment in post-processing steps.

Therefore, the present invention aims to provide excellent elongation and
It is an object of the present invention to provide a polyurethane-polyamide composite fiber that can improve recovery stress characteristics after crimp development without impairing recovery characteristics, and can also improve heat resistance and improve product characteristics after heat treatment. Main purpose.

[Means for Solving the Problem] In order to achieve the above object, the polyurethane according to the present invention
The polyamide eccentric composite fiber is an eccentric composite fiber consisting of a polyurethane component and a polyamide component, in which the polyurethane component has a DSC melting peak temperature of 190 to 23
It is characterized by being made of elastic polyurethane with a temperature of 0°C.

The elastic polyurethane used as the polyurethane component in the present invention is required to have a DSC melting peak temperature of 190 to 230°C. The temperature is preferably 192°C or higher, and more preferably 195°C or higher. If this peak temperature is less than 190°C, the object of the present invention cannot be achieved because the heat resistance and elongation recovery properties are poor. Also,
This peak temperature is at most about 230°C, and preferably about 220°C. If this peak temperature exceeds 230° C., the feel (soft feel) and elongation recovery characteristics of stretch knitted products such as stockings will be poor, making it difficult to produce sufficiently excellent products.

This peak temperature may be determined by the following method.

Approximately 10 mg of the sample was packed in an aluminum pan, and subjected to DSC using a differential scanning calorimeter (DSC-4 manufactured by PerkinElmer) at a heating rate of 10°C/min and a sample of approximately 10 mg.
Find the melting curve. The melting curve has one or more endothermic peaks. Among the endothermic peaks, the peak on the substantially highest temperature side related to melting of the hard segment crystal portion is taken, and the peak temperature is taken as the DSC melting peak temperature.

For example, Example No. In the diagram showing the DSC melting curves for A1, B2, and C2, if a single peak is shown like the melting curve of Al, the temperature of that peak is shown, and if it clearly shows multiple peaks like the melting curve of C2. If the decomposition exothermic peak intersects with the melting peak as in the melting curve of B2, read the corrected peak repeatedly and calculate the temperature of the highest peak. Just take it.

For the above DSC measurement, a polyurethane component is obtained by completely dissolving only the polyamide component from the composite fiber with formic acid at room temperature, washing with water, air drying for 12 hours or more, and using this polyurethane component as a measurement sample.

The DSC melting peak temperature of this elastic polyurethane was set to 190
In order to achieve a temperature range of ~230°C, it is necessary to adjust the ratio of crystal-forming parts (hard segments) of polyurethane, the polyurethane melting temperature, the molecular weight of a certain polyol, the blocking properties of low-molecular-weight diol parts, etc., or the method of spinning. In order to adjust the orientation characteristics and the completeness of the crystal structure of the composite fiber, aging, elongation, heat treatment, etc. may be used in combination.

For example, when adjusting the ratio of hard segments (chain extenders such as low-molecular diols and diamines) and soft segments (polyol fractions) of polyurethane, the weight ratio of low-molecular diol/boliol should be adjusted to 17:83 to 83. 25
:75 range is sufficient. Further 20:80-25:
A range of 75 is preferred. Furthermore, in order to set the DSC melting peak temperature to {90 to 230°C, it is necessary to
Preferably, heat treatment is performed at a temperature of about 0 to 160°C,
This heat treatment can further improve the heat resistance in high-order processing of the composite fiber.

In order to obtain the composite fiber specified in claim 1, 150 kg of the polyurethane component is required before melt spinning.
It is preferred to use an elastic polyurethane having a 100% tensile stress of I/cnf or higher.

The conjugate fiber obtained using this elastic polyurethane further has good heat resistance, and the resulting stretch knitted product has good fit, hand, elongation recovery characteristics, and crimp characteristics.

This value of 100% tensile stress is a value measured according to the JIS K7311 method, and may be measured using an injection molded 2 mm thick sheet at a tensile speed of 300 m/min.

As for the type of elastic polyurethane, elastic polyurethanes such as polycarbonate polyurethane, polyester polyurethane, polylactone polyurethane, and polyether polyurethane may be used alone, in copolymerization, or as a mixture. Among these, elastic polyurethanes consisting essentially only of polycarbonate-based polyurethane, or elastic polyurethanes containing 10% by weight or more of polycarbonate-based polyurethane as a copolymerization component or mixed component, are preferred from the viewpoint of adhesion with polyamide components, etc. preferable. In addition, a small amount (for example, 20
Other compounds such as polyester and polyisocyanate may be mixed as long as the amount is 10% by weight or less, preferably 10% by weight or less.

The polyol for obtaining the polycarbonate polyurethane includes 4,4'-dioxydiphenyl-2,
Examples include aromatic polycarbonate from 2'-propane (bisphenol A) and aliphatic polycarbonate obtained by reaction of aliphatic dihydric alcohol with phosgene.

Moreover, polyols for obtaining polyether polyurethane include poly(oxyethylene) glycol, poly(oxypropylene) glycol, poly(tetramethylene) glycol, and the like. Furthermore, as polyols for obtaining polyester polyurethane, acids such as adipic acid, glutaric acid or sebacic acid, ethylene glycol, 1,4-butylene glycol, 1,3- or 2,3-butanediol, 2 , 5-hexanediol and other glycols by a condensation reaction.

The molecular weight of these polyols is preferably about 600 to 4,000.

Further, examples of the diisocyanate for obtaining elastic polyurethane include diphenylmethane diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, isophorone diisocyanate, lysine diisocyanate, and the like. Examples of chain extenders include low molecular weight glycols, hydrazine, ethylenediamine, bis-β-hexanone, and the like. The molar ratio of one NCO end group to -OH end group in the polymerization raw material (-NGO/-OH
) may be about 1.00 to ■,15.

These polymerization raw materials can be polymerized by a conventional polyurethane polymerization method such as a one-shot method or a pre-volume method, or by rough polymer mixing or additive mixing to obtain an elastic polyurethane used as a base polymer for a polyurethane component.

In order to suppress viscosity variations during melt spinning of this elastic polyurethane, it is effective to control the degree of polymerization of the polyurethane within an appropriate range depending on the polyurethane composition. It is preferable to do so.

On the other hand, as the polyamide component used in the present invention, melt-spun polyamides such as nylon 6, nylon 66, nylon 6/10, or copolyamides thereof may be used. In order to obtain a composite fiber with good practical physical properties such as abrasion resistance, it is preferable to use polyamide with a melting point of 200° C. or higher. However, for composite spinning with polyurethane, a polyamide with a too high melting point is not preferred, and it is practically preferable that the melting point is at most about 300°C.

Among these, polyamides having a melting point of 210° C. or higher are preferred, and polyamides consisting essentially of nylon 6 or nylon 66 are particularly preferred. The degree of polymerization may be such that it has a relative viscosity ηr of a level used for clothing fibers, for example, a relative viscosity of sulfuric acid of about 2.0 to 2.8. This polyamide component may contain conventional additives such as heat-resistant agents, light-resistant agents, and matting agents.

Basically, the above-mentioned polyurethane component and some polyamide may be spun into an eccentric composite fiber in the same manner as conventional melt composite spinning of polyamide and polyurethane. For example, each volima [composition] is
After supplying and melting separately, the composite is spun and drawn using a composite spinneret heated to about 230 to 290°C.
Latently crimpable composite fibers may be produced using a normal yarn spinning method. The stretching method may be hot stretching or cold stretching, and cold stretching is particularly preferred from the viewpoint of uniformity.

Furthermore, relaxing heat fixation may be performed.

The composite structure may be any eccentric composite structure that can obtain latent crimpability that can exhibit coiled crimp through crimp development treatment, such as an eccentric core-sheath type composite structure or a side-by-side bonded composite structure. It will be done. The composite ratio is
Although it depends on the composite structure, generally 8 0/2
It may be about 0 to 20/80. Further, it is preferable that the polymer occupying the outer peripheral surface of the fiber is polyamide, or that the proportion thereof is large.

The polyurethane polyamide eccentric composite fiber obtained by melt composite spinning is crimped in a conventional manner and exhibits elastic properties as a coiled crimped fiber.

[Function] The composite fiber according to the present invention has an elastic polyurethane constituting a portion of the polyurethane, which has a higher D of 90°C or higher than conventional
Since it has an SC melting peak temperature, the composite fiber has excellent heat resistance, and can also exhibit excellent strength and elongation/recovery properties.

Therefore, when this composite fiber is used, even if it undergoes post-processing such as weaving, dyeing, heat-setting, and crimp development to produce a final product, the deterioration of physical properties during subsequent processing can be greatly reduced, and it can be used in stretchable final products. The strength and elongation characteristics of the fibers have been greatly improved compared to conventional knitted fabrics made of polyurethane and polyamide fibers, and they can exhibit excellent strength and elongation recovery characteristics, making them practical and highly fit, as well as being finely crimped. A final product with beautiful stitches and excellent texture can be obtained.

On the other hand, in conventional composite fibers, the DSC melting peak temperature of the elastic polyurethane constituting the polyurethane component is 1.
Since the temperature is as low as less than 90° C., the heat resistance and elongation recovery characteristics are not sufficient, and there are significant restrictions on heating in post-processing steps during practical stocking production.

The DSC melting peak temperature serves as an index of heat resistance and is also related to stress during elongation recovery. That is, this DSC
A high melting peak temperature means that the crystalline parts (hard segments), which are the nodules of the elastic polyurethane, are more complete, and the number of crystal domains has also increased, resulting in higher rubber elasticity. It is. Therefore, in order to improve the elongation recovery stress and heat resistance that contribute to the fit of textile products, it is effective to set the DSC melting peak temperature to 190° C. or higher, which is higher than before.

[Example] Example 1 A 1=1 mixed polyol of polycarbonate and polycaprolactone each having a number average molecular weight of 2000 was used, 1,4-butylene glycol was used as a chain extender, and diphenyl was used as a diisocyanate. A polyurethane polymer was obtained by polymerization using methane diisocyanate by a conventional one-shot method. The obtained polymer was pulverized, then melt-extruded using an extruder and pelletized.

During the above polymerization, one NGO end group in the polymerization raw material and -
The molar ratio with the OH end group (-NGO/-OH) is 1.07
And so. Furthermore, two types of elastic polyurethanes with different weight ratios of 1,4-butylene glycol/mixed polyol of 16/84 or 21/79 were synthesized. The polyurethane viscosity level was adjusted during synthesis, and each melt viscosity was 1.
0 0 0 0 poiu or 2 0 0 0 0
Poise elastic polyurethane was used.

The melt viscosity and 100% tensile stress of each of the obtained elastic polyurethanes were measured, and the results are shown in Table 2.

The relative viscosity of these elastic polyurethanes and 98% sulfuric acid is 2.4.
0 polycapramide at 230°C and 260°C, respectively.
They were melted separately at ℃ and fed to a composite spinning machine, then spun into an eccentric core-sheath shape with a composite ratio of 50/50 in a composite spinneret heated to 250℃, cooled and lubricated by the usual method. The resulting undrawn yarn was wound at a speed of 600 m/min. After stretching to 0 times, the yarn was continuously run in contact with a hot plate set at room temperature to 140° C. at a constant length to obtain a heat-treated 20-denier, 2-filament latent crimpable composite filament yarn. The strength and elongation characteristics of the obtained filament yarn and the DSC melting temperature of the polyurethane component were measured, and the results are shown in Table 1. Also, no
, Al, B2 and C2 are shown in the figure.

This composite filament yarn was knitted into a stocking fabric using a normal method at a knitting speed of 800 rpm,
A stocking product was manufactured by heat-setting with pressurized steam at 10°C, and its elongation recovery stress characteristics, fit, and hand were measured, and the results are also shown in Table 1.

The above physical properties were measured by the following methods.

Crimp characteristics of stockings: Constant extension type tensile tester TOM
-100E type (manufactured by Shinko Tsushin Kogyo Co., Ltd.), the length of the stocking sample when stretched under a load of 2 kg is defined as L1, and the stocking sample is folded in half and subjected to a tensile tester. Draw a stress-strain hysteresis curve when the sample is stretched to 75% of 2 and immediately recovered. From this hysteresis curve, the stress value (g) at the time of 75% elongation of L1/2, and from the recovery curve, L1
Stress value (g) at the time of recovery to 60% elongation length of /2
and the value obtained by dividing them by 1/2 is 7.
It was expressed as a value of 5% elongation stress and 60% recovery stress. These values are indicators of the fit of the stockings, and the higher the value, the better the fit.

Fit and feel: These are the relative evaluation results obtained by wearing test the product stockings, and are shown using the following criteria: ◎: Very good, ○: Good, △: Slightly poor, ×: Poor.

As is clear from the results in Table 1, composite fibers made of elastic polyurethane whose polyurethane component has a DSC melting peak temperature of 190°C or higher had excellent strength and elongation properties, stocking fit, and feel. . Also,
100% tensile stress is 150k as polyurethane component
When elastic polyurethanes (Nos. C and D) with gl/cof or higher were used, these properties were even better, resulting in extremely good products.

[Effects of the Invention] Since the polyurethane/polyamide eccentric composite fiber according to the present invention is made of elastic polyurethane with a high DSC peak temperature of 190°C, the recovery stress characteristics of the coiled crimped fiber after crimping is This can be significantly improved, and therefore, a stretch knitted product with even further improved fit can be obtained.

Furthermore, since the heat resistance is improved, it is possible to prevent quality deterioration during crimp development treatment and heat setting, and it is also possible to improve the strength and elongation characteristics of stretch knitted fabric products.

The composite fiber according to the present invention can be widely used in textile products that require a high fit, but is particularly useful for stockings and stretchable tricot products, and can also be used for other hodgepodge products such as socks. I can do it.

[Brief explanation of drawings]

The figure illustrates the DSC melting curves of the polyurethane component, of which 82 and C2 illustrate the melting curves of the polyurethane component of the composite fiber according to the invention.

Claims (3)

[Claims] (1) In an eccentric composite fiber consisting of a polyurethane component and a polyamide component, the polyurethane component is DS
C. A polyurethane/polyamide composite fiber comprising elastic polyurethane having a melting peak temperature of 190 to 230°C. (2) The polyurethane/polyamide composite fiber according to claim 1, wherein 10% by weight or more of the elastic polyurethane is polycarbonate polyurethane. (3) When producing the polyurethane-polyamide composite fiber according to claim 1 by melt-composite spinning a polyurethane component and a polyamide component, the polyurethane component has a 100% tensile stress of 150 kgf/cm^
A method for producing a polyurethane/polyamide composite fiber, characterized by using an elastic polyurethane having an elasticity of 2 or more.