JP2856966B2 - Polyamide hollow and / or modified fibers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to hollow and / or modified polyamide fibers and a method for producing the same. More particularly, the present invention relates to a polyamide fiber having improved hollowness and / or irregularity and a method for producing the same.

[0002] Here, "hollow and / or modified fibers"
The phrase is a hollow fiber whose cross section of a single fiber is round or irregular,
A single fiber has a solid, irregular and solid yarn cross section, or a yarn obtained by mixing these single fibers.

[0003]

2. Description of the Related Art To improve the deformability and hollow formability of polyamide fibers, there have conventionally been employed means for devising a die shape or increasing the degree of polymerization of a polymer to increase the melt viscosity. Was. However, in the former method, not only the formation of the cross section itself is difficult, but also the number of single yarns is limited, and it is very difficult to satisfy required characteristics. on the other hand,
In the latter method, the spinning itself becomes difficult as the melt viscosity increases, and therefore, there is a limit to the improvement of the degree of irregularity and the hollow ratio by this method.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a method for producing hollow and / or irregularly shaped polyamide fibers, which is a method for improving hollowness and / or degree of irregularity. It is an object of the present invention to provide a hollow and / or modified polyamide fiber and a method for producing the same, without having to rely on a change in the degree of polymerization of the polyamide.

[0005]

According to the study of the present inventors, a polyamide having a terminal carboxyl group of a certain amount or less, more preferably a ratio of the terminal amino group amount to the terminal carboxyl group amount (terminal amino group amount). / Amount of terminal carboxyl group)
When the melt-spinning is performed after blending a metal salt of a saturated fatty acid, which has been used to prevent yarn breakage during melt-spinning, in relation to the amount of carboxyl groups, with respect to a polyamide having 1 or more. It has been found that the hollowness and / or irregularity of the yarn is significantly improved.

Thus, according to the present invention, in a polyamide hollow and / or modified fiber blended with a metal salt of a saturated fatty acid having at least 10 carbon atoms, the amount of terminal carboxyl groups (X) of the polyamide constituting the fiber is determined. Is 6
0 gram equivalent / ton or less, and the metal salt of the saturated fatty acid is Y≥ depending on the amount of the terminal carboxyl group (X).
0.00871X-0.13 (where Y is a compounding amount of a metal salt of a saturated fatty acid), wherein the polyamide hollow and / or modified fiber is blended in an amount satisfying the following.
Further, when melt-spinning polyamide hollow and / or modified fibers, the polyamide having an amount of terminal carboxyl groups (X) of not more than 60 gram equivalent / ton is used depending on the amount of the terminal carboxyl groups (X). The metal salt of the saturated fatty acid having at least 10 carbon atoms is added to the polyamide by Y ≧ 0.00871X−0.13 (where Y
(A blending amount of a metal salt of a saturated fatty acid) and then melt-spinning, and a process for producing hollow and / or modified polyamide fibers is provided.

In the present invention, the above-mentioned metal salt of a saturated fatty acid (hereinafter sometimes simply referred to as “metal salt”) refers to
It means a metal compound of a higher fatty acid. Higher fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, montanic acid and the like, and the metals mean alkali metals, alkaline earth metals, earth metals, preferably sodium, calcium, magnesium. No. Preferably, it is magnesium.

As a method for blending the metal salt with the polyamide, a dry blending method, a master chip blending method, a liquid addition method, and a polymerization addition method are employed.

[0009] Melt spinning can be performed by a conventional method. That is, the polyamide containing the above metal salt is melt-spun, and after cooling and solidifying, an oil agent is applied.
What is necessary is just to wind up after performing processing, such as heat treatment and entanglement processing. The polyamide may be blended with a matting agent such as titanium dioxide, an additive such as a lightfastness improver, and / or a pigment or dye.

A major feature of the present invention is that in producing hollow and / or irregularly shaped polyamide fibers, the above-mentioned polyamide fibers are prepared in accordance with the amount of terminal carboxyl groups of the polymer without depending on the shape of the die or the polymer having a high degree of polymerization. A desired object has been achieved by melt-spinning a polyamide blended with a metal salt of (1). For this purpose, the amount of terminal carboxyl groups (X) of the polymer is at most 60 gram equivalent / ton, and, depending on the amount of terminal carboxyl groups (X), the blending amount of metal salt (Y) (polymer 100 parts) is defined as Y ≧ 0.00871X−0.13. Either of these two requirements is missing, no improvement in the hollow ratio or degree of irregularity can be expected, and in the present invention, the object of the present invention is achieved only when these two requirements are satisfied simultaneously. Therefore, in the present invention, two requirements of the amount of terminal carboxyl groups Y ≧ 0.00871X−0.13 are critical, and their significance will be described through the results of model experiments. The polyamide having a terminal carboxyl group content of 60 gram equivalent / ton or less can be easily obtained by using a terminal blocking agent such as a monoamine.

[0011]

[Model Experiment 1] Table 1 shows the characteristics of the polymer used in this experiment. The amount of terminal amino groups was determined by dissolving the polymer in m-cresol and neutralized and titrated with p-toluenesulfonic acid.The amount of terminal carboxyl groups was dissolved in benzyl alcohol and dissolved in sodium hydroxide solution. The values obtained by the sum titration are shown, and are expressed in units of gram equivalent per 1 million gram of the polymer. The degree of polymerization was 35 for a solution having a concentration of 0.4 g / 100 ml using m-cresol as a solvent.
It is expressed as the intrinsic viscosity measured at ° C. (Hereinafter [η]
Abbreviated)

[0012]

[Table 1]

For each of the polymers shown in Table 1, magnesium stearate (hereinafter abbreviated as St-Mg) was added in an amount of 0 to 0.
It was melt-spun out containing 1.0% by weight. Spinning was performed at a spinning temperature of 250 ° C, a spinning speed of 900 m / min, and a drawing speed of 3
2,000 m / min, a draw ratio of 3.25 times, using an extruder melt spinning machine, slit width 0.12 m
An 830 denier, 46 filament drawn yarn was obtained through a spinneret having a triangular hollow section having 46 m pores.
The hollow ratio was represented by the ratio of the specific gravity of the hollow fiber to the specific gravity of the solid yarn.

Table 2 shows the results. The comparative example is a result of spinning the polymer type D at a spinning temperature of 240 ° C.

[0015]

[Table 2]

What should be noted here is that the degree of increase in the hollow ratio differs depending on the type of the polymer, which can be summarized as follows.

In the case of a polyamide having a terminal carboxyl group content of more than 60 gram equivalent / ton, the hollow ratio does not substantially change regardless of the amount of the metal salt.

In the case of polyamide having a terminal carboxyl group content of 60 gram equivalent / ton or less, St-Mg
The hollow ratio greatly increased with the increase in the blending amount of St-Mg.
%, The hollow ratio almost doubles as compared with the blank.

The degree of increase in the hollow ratio also depends on the ratio of the amount of terminal amino groups to the amount of terminal carboxyl groups (terminal amino group amount / terminal carboxyl group amount), and this ratio is at least 1, especially 3. It is preferably 5 or more.

Therefore, based on the above fact (Experiment N
o. 8 to 25), FIG. 1 summarizes the amount of St-Mg necessary for increasing the hollow ratio in relation to the amount of terminal carboxyl groups. The straight line in the table is Y = 0.00871X-0.
The reference numeral 13 indicates. Therefore, in the present invention, it is sufficient to use a metal salt in an amount of Y or more represented by the above formula. However, there is no special limit on the upper limit,
Generally, about 1.2% is appropriate.

The above results are also applicable to the melt-spinning of modified cross-section yarns.

[0022]

[Model Experiment 2] Among the polymers shown in Table 1, St types were used for polymer types B and D, which had significantly different hollow ratios.
-Mg was contained in an amount of 0 to 2.0% by weight and melt spun. The spinning was performed at a spinning temperature of 250 ° C. and a spinning speed of 800 m / min, and a 60-denier, 10-filament undrawn yarn was obtained through a spinneret having a trilobal cross section having 10 pores with a slit width of 0.055 mm at a spinning speed of 800 m / min. The degree of irregularity is represented by the ratio of the circumscribed circle to the inscribed circle in the cross section as shown in FIG. Table 3 shows S
FIG. 1 shows a change in the degree of irregularity with respect to the amount of t-Mg added by a broken line in FIG.

[0023]

[Table 3] This broken line is represented by Y = 0.0075X-0.15.

As shown in FIG. 1, in the case of producing a modified yarn, St-M
It can be seen that the effect of g becomes more apparent.

[0025]

In the present invention, the metal salt of a fatty acid used for improving the hollow ratio and / or the degree of irregularity has been provided in another form.

For example, Japanese Patent Publication No. 48-28975 discloses an effect of preventing the breakage of a single yarn caused by the adhesion of a polyamide to a spinneret when a specific magnesium salt or a magnesium salt of a carboxylic acid is contained and spun. It is disclosed to be expressed. Although magnesium stearate is described as an example of a magnesium salt of a carboxylic acid, the action and effect are only to prevent adhesion and deterioration of the polymer by magnesium metal. Further, as for the polymer, only those having a terminal amino group amount and a terminal carboxyl group amount of about 66 gram equivalent / ton are indicated. Further, Japanese Patent Application Laid-Open No. 62-62911 discloses a method for preventing yarn breakage during high-speed spinning by containing a magnesium compound (as a higher fatty acid salt and oxide). In this case, only the effect of reducing the melt viscosity of nylon and reducing the unevenness of viscosity is taught. JP-A-63-92717 discloses that a specific pigment (isoindolinone-based pigment) and a metal stearate are contained in a polyamide-dipped liquid pigment. In this case, a metal called stearate is used as a chemical reaction preventing means only in order to prevent amide bonds in the pigment, which is an isoindolinone pigment, from causing a transamidation reaction with the polyamide to cause cross-linking, increase in viscosity, and poor yarn production. Uses salt. Thus, the prior art only shows that the effect of the magnesium salt of the carboxylic acid is to prevent the polyamide from sticking or exuding to the spinneret; the melt viscosity of a single polymer Only a slight reduction in the viscosity and the effect of improving the spinnability under the limited conditions of high-speed spinning due to the reduction in viscosity unevenness; having an amide bond in a pigment called an isoindolinone-based pigment,
Only a metal stearic acid salt is used as a chemical reaction preventing means for preventing a polyamide-amid exchange reaction from occurring and resulting in poor spinning properties.

That is, a polymer having a terminal carboxyl group content of 60 gram equivalent / ton is used to improve the hollow ratio and / or the degree of irregularity through these known techniques, and a metal salt is blended in accordance with the terminal carboxyl group amount. I can't detect any technical thought of doing it.

On the other hand, in the present invention, the internal lubrication effect
Introducing the concept of external lubricating effect and examining their effects in detail in relation to the compatibility between the polymer and the additive, the effect differs depending on the polarity (ratio of terminal groups) of the polymer I found something.

That is, when a metal salt is added to various types of polymers, it is found that a polymer having a smaller amount of terminal carboxyl groups of the polyamide has a larger change in flow rate at the time of discharge, which is a typical characteristic of the external lubricating effect. Was.

On the other hand, it has been found that a decrease in melt viscosity, which is a typical characteristic of the internal lubricating effect, is greater in a polymer having a large amount of terminal carboxyl groups. That is, the balance between the internal lubricating effect and the external lubricating effect, which is the lubricating effect of the metal salt, changes depending on the number of terminal groups of the polyamide. More specifically, the distribution state (interaction) of the metal salt in the polymer is changed. I found something different. In the case of a polymer with a large external lubrication effect, the metal salt is distributed at the polymer interface, so the details of the mechanism of action are still unknown, but the metal salt wraps the polymer during ejection and the apparent surface tension increases. However, it is presumed that the deformability and hollow formability are improved.
It has also been found that the distribution state of the agent exhibiting the external lubricating effect differs depending on the compatibility between the agent and the polymer. More specifically, this effect varies depending on the amount and ratio of the terminal groups of the polyamide, and the smaller the amount of the terminal carboxyl groups, the easier the distribution at the interface between the polymer and the metal.
It is considered that this is because the metal salt has a property of easily coordinating to the carboxyl terminal group. As described above, the present invention is to control the surface tension of a polymer by the chemical structure properties of the terminal group of the polyamide and the metal salt, and thereby succeeded in improving the deformability and hollow formability. is there.

[0031]

According to the present invention, simple means without resort to large means of uncertainty, such as devising the shape of the die, or means requiring extra steps in operation, such as increasing the degree of polymerization of the polymer in advance, is simplified. The desired hollow ratio and degree of irregularity can be obtained by the means, and the industrial significance is great.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the amount of a metal salt of a saturated fatty acid having 10 or more carbon atoms and the amount of terminal carboxyl groups of a polyamide.

FIG. 2 is an explanatory diagram of an irregularity.

[Explanation of symbols]

Y Compounding amount of the above metal salt X Amount of terminal carboxyl group in polyamide (gram equivalent / ton) R Diameter of circumcircle of hetero yarn r Diameter of inscribed circle of hetero yarn

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) D01F 6/90 301 D01F 6/60 321 D01F 6/60 341

Claims (10)

(57) [Claims] A polyamide hollow and / or modified fiber blended with a metal salt of a saturated fatty acid having at least 10 carbon atoms has a terminal carboxyl group content (X) of a polyamide constituting the fiber of 60 gram equivalent / ton. And the metal salt of the saturated fatty acid is y ≧ 0.00871X−0.13 depending on the amount of the terminal carboxyl group (X).
(Where Y is the amount of the metal salt of a saturated fatty acid), wherein the polyamide hollow and / or modified fibers are blended in an amount that satisfies the following formula: 2. The hollow and / or modified polyamide fiber according to claim 1, wherein the ratio of the amount of terminal amino groups to the amount of terminal carboxyl groups (terminal amino group amount / terminal carboxyl group amount) of the polyamide is 1 or more. 3. The hollow and / or modified polyamide fiber according to claim 1, wherein the ratio of the amount of terminal amino groups to the amount of terminal carboxyl groups (terminal amino group amount / terminal carboxyl group amount) of the polyamide is 3 or more. 4. The hollow and / or modified polyamide fiber according to claim 1, wherein the metal salt of a saturated fatty acid having at least 10 carbon atoms is a magnesium salt of stearic acid. 5. Polyamide hollow and / or modified fibers according to claim 1, wherein the polyamide is polycaproamide. 6. A polyamide having a terminal carboxyl group content (X) of not more than 60 gram equivalent / ton when melt-spinning a hollow and / or modified polyamide fiber. And the metal salt of the saturated fatty acid having at least 10 carbon atoms is added to the polyamide by y ≧ 0.00871, −0.13 (where,
Y is a blending amount of a metal salt of a saturated fatty acid), and then melt-spun. 7. The process for producing hollow and / or modified polyamide fibers according to claim 6, wherein the ratio of the amount of terminal amino groups to the amount of terminal carboxyl groups (the amount of terminal amino groups / the amount of terminal carboxyl groups) of the polyamide is 1 or more. . 8. The polyamide hollow and / or modified fiber according to claim 6, wherein the ratio of the amount of terminal amino groups to the amount of terminal carboxyl groups (the amount of terminal amino groups / the amount of terminal carboxyl groups) of the polyamide is 3 or more. Manufacturing method. 9. The hollow polyamide and / or irregular polyamide fiber according to claim 1, wherein the metal salt of a saturated fatty acid having at least 10 carbon atoms is a magnesium salt of stearic acid. A method for producing deformed fibers. 10. The process according to claim 6, wherein the polyamide is polycaproamide.