JPH0598513A - Hygroscopic polyamide fiber - Google Patents

Abstract

PURPOSE:To obtain the subject fiber, containing a specific amount of a specified condensate having terminal groups converted into carboxyl groups and excellent in physical and process performances. CONSTITUTION:The objective fiber containing a condensate of (A) two or more polyoxyalkylene glycols, expressed by formula I (R1 and R2 are H or hydrocarbon; m is >=1) and having different molecular weights with (B) a sulfonate compound [e.g. a metal 3,5-bis(carbomethoxy)benzenesulfonate] expressed by formula II [R3 and R4 are same as R1; (n) is 1-4; Z is aromatic ring; M is metal, provided that its dehydration ratio is >=15] in which terminal groups are converted into carboxyl groups wit an acid anhydride. The amount of the condensate is 0.05-0.7mol expressed in terms of sulfonate group based on 1kg polyamide fiber (preferably nylon 6, etc.).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a hygroscopic polyamide fiber having excellent physical performance and processability. More specifically, the present invention relates to hygroscopic polyamide fibers having the original characteristics of polyamide and having excellent durability.

[0002]

2. Description of the Related Art Polyamide fibers are widely and generally used in various forms such as fibers and films due to their excellent properties. However, such polyamide fibers are generally hydrophobic, which is why
There are some fields that cannot be used due to lack of hygroscopicity. Particularly in fibers and films, this hydrophobic property is fatal and the field of use is extremely limited.

Therefore, various proposals have been made in the past for imparting hygroscopicity to polyamide fibers, but few have been put to practical use yet. For example, many proposals have been made to copolymerize or blend a hydrophilic third component with a fiber-forming polyamide component to attempt to improve hygroscopicity. However, the hygroscopicity of the polyamide fiber obtained by such a method is not sufficient, and the physical property value of the fiber obtained by increasing the addition amount in order to improve the performance becomes poor in practicality, and originally, Had to sacrifice the excellent physical properties of these polyamide fibers.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a polyamide fiber having excellent hygroscopicity by solving the above-mentioned problems of the conventionally known polyamide fiber.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have previously contracted polyoxyalkylene glycol and a sulfonate compound as proposed on the name of the invention, a thermoplastic synthetic resin molded product, filed on October 02, 1991. It was found that the use of the polymerized condensate significantly improves the hygroscopicity as compared with the case where they are used alone or when they are simply copolymerized.

[0006] Further, the name of the application filed on October 02, 1991, the hygroscopic polyamide molded article, as proposed in the present invention, by converting the terminal group of this condensate into a carboxyl group and blending with the polyamide, It was discovered that the decline could be prevented. Furthermore, as a result of pursuing the relationship between the metal ion species of the sulfonate compound introduced into the polyamide molded article and the hygroscopic ability, it was found that the polyvalent metal ion having a high hydration tendency was combined with the sulfonate compound to be present in a specific amount or more, and thus higher. The present invention has been completed by discovering that hygroscopicity can be imparted.

That is, the present invention is a condensate of two or more kinds of polyoxyalkylene glycols having different average molecular weights represented by the formula (1) and a sulfonate compound represented by the formula (2), and It contains 0.05 mol or more and 0.7 mol or less of a sulfonic acid group per 1 kg of fiber in which a terminal group is converted to a carboxyl group, and M in the above formula (2) is a metal having a hydration index of 15 or more. It is a hygroscopic polyamide fiber characterized by being present.

[0008]

[Chemical 2]

The polyamide used in the present invention is preferably nylon 6, nylon 66, nylon 610 or the like. Of these, nylon 6 and nylon 66 are particularly preferable. It should be noted that there is no problem even if a mixture of these as main components and other components is copolymerized and / or mixed, or a mixture thereof is used. The polyoxyalkylene glycol used in the present invention has a repeating unit of —CHR.
₁ -CHR ₂ -O- (where, R _1, R ₂ is hydrogen or a hydrocarbon.) Becomes If forming a condensate of a structure and is the sulfonate compound or may be applied in any kind of thing, polyethylene Glycol and polypropylene glycol are preferable, and polyethylene glycol is particularly preferable.

The sulfonate compound used in the present invention is
For example, 3,5-dicarboxybenzenesulfonic acid metal salt, 3,5-bis (carbomethoxy) benzenesulfonic acid metal salt, 3,5-bis (hydroxyethoxy) benzenesulfonic acid metal salt, 1,8-bis ( Examples thereof include carboxymethoxy) naphthalene-3-sulfonic acid metal salt, 2,6-bis (carboxymethoxy) naphthalene-4-sulfonic acid metal salt, and 1,5-bis (carbomethoxy) benzenesulfonic acid metal salt.

Regarding the molecular weight of the polyoxyalkylene glycol used in the present invention, it is more preferable for carrying out the present invention that the above-mentioned condensate can be formed and the following conditions are satisfied. First, in order not to impair the excellent properties inherent in polyamide, it is self-evident that the condensate to be blended preferably has a high moisture absorption performance. In the condensate used in the present invention, the higher the weight fraction of the sulfonate compound contained, the higher the moisture absorption performance. That is, since the sulfonate compound and the polyoxyalkylene glycol react in equimolar amounts, it is preferable that the molecular weight of the polyoxyalkylene glycol is low.

However, there is a limit to the lower molecular weight, and when both R ₁ and R _{2 of the} formula (1) are hydrogen and the weight fraction of ethylene glycol having m of 1 is 20% or more, the heat melting property is high. Is not preferable because it becomes defective. Therefore, the molecular weight of the polyoxyalkylene glycol used is preferably 100 or more. On the other hand, although the reason is not clear, if the condensate is composed of only polyoxyalkylene glycol having a molecular weight of less than 1000, the hygroscopicity is lowered even if the polysulfonate has the same amount of sulfonate compound, and therefore the higher the molecular weight is, the higher the molecular weight is. It is preferably 1,000 or more.

Therefore, as a result of intensive studies to satisfy the above-mentioned contradictory conditions, the present inventors have found that the polyoxyalkylene glycol to be reacted with a sulfonate compound has a molecular weight in order to prevent a decrease in hygroscopicity of the condensate. Of 1000 to 4000 are used in part, and in order to increase the weight fraction of the sulfonate compound and increase the hygroscopicity of the condensate, one having a low molecular weight of 100 or more and less than 100, and more preferably 150 or more. A heat-meltable condensate having excellent hygroscopicity could be synthesized by using a 600 or less one and synthesizing the condensate by matching the molar ratio with the sulfonate compound.

However, when the hygroscopic polyamide fiber containing the above-mentioned hygroscopic heat-meltable condensate was passed through a usual dyeing process, it was found that the hygroscopicity was lowered. This is because most of the end groups of the condensate blended were OH groups, so the binding force with the polyamide was weak,
It was found that the hygroscopicity was reduced due to the removal of a part of the condensate. Therefore, in order to strengthen the binding force between the condensate and the polyamide, the end group of the condensate was converted to a carboxyl group and blended with the polyamide to prevent the condensate from falling off in a later step such as dyeing, which was excellent. It has been discovered that it can maintain hygroscopicity. To make the end group of the condensate a carboxyl group, it can be easily converted by forming an acid anhydride or the like and then reacting it with the OH group portion of the polyoxyalkylene glycol.

For example, 108 parts (0.72 mol) of triethylene glycol having a molecular weight of 150 and an average molecular weight of 1,000.
68 parts (0.068 mol) of polyethylene glycol,
35% ethylene glycol solution of 3,5-bis (hydroxylethoxy) sulfoisophthalate sodium salt (however, a reaction mixture of 70% hydroxyethoxy group and 30% carboxymethoxy group) 756 parts (0.788 mol) and a catalyst and the like. It can be easily obtained by charging the compound into a polymerization machine, conducting a polycondensation reaction in the presence of a catalyst, and adding an acid anhydride such as trimellitic anhydride and reacting immediately before the reaction is completed.

The condensate used in the present invention refers to a polycondensation reaction product obtained from a polycondensation reaction and having a low polymerization degree to a high polymerization degree. Although the degree of polymerization of the condensate can be from low to high, it can be used in a suitable range from the viewpoint of reactivity and the composition to be obtained, and therefore it is preferable to select as necessary. It is essential that the condensate used in the present invention exists in a block copolymer form in the polyamide, and the thermal history such that the sulfonate compound component and the polyoxyalkylene glycol component are randomly copolymerized should be avoided as much as possible. .. The reason why high hygroscopicity is exhibited by block copolymerizing the condensate as compared with the random copolymer is not clear, but when present in the block copolymer form, the alkylene glycol group and the metal sulfonate group in the sulfonate compound are It is speculated that the closer proximity results in the higher hygroscopicity expected from that of the random copolymer. Therefore, it is preferable that the condensate used in the present invention is added to the polyamide at the time of molding or immediately before the completion of the resin synthesis reaction.

The inventors of the present invention have conducted extensive studies to further improve hygroscopicity, and as a result, have a high hydration index of 15 or more, which indicates a high hydration tendency, which is a value obtained by dividing the number of charges of metal ions by the radius (nm) of metal ions. It has been surprisingly discovered that higher hygroscopicity can be imparted by binding a valent metal ion to a sulfonate compound and allowing it to exist in a specific amount or more.
The hydration index referred to in the present invention is a number obtained by dividing the number of charges of a metal by the crystal radius (nm) as described above, and is a parameter indicating the degree of hydration ability of each metal ion. The ionic radius of the metal ion as used herein is the bond radius of the metal in the ionic compound, and is used to calculate the hydration index in the present invention. D. Shanon (Acta
Crystallogr. ), A32, 751-76
The values on page 7 (1976) were used and the coordination number was unified to 6. For the transition metal, the numerical value in the low spin state was used.

The hydration index of each metal ion is exemplified below: Li ⁺ (11.1), Na ⁺ (8.6), K
⁺ (6.6), Rb ⁺ (6.0), Cs ⁺ (5.5),
Be ²⁺ (33.9), Mg ²⁺ (23.3), Ba ²⁺ (1
3.4), Mn ²⁺ (24.7), Co ²⁺ (25.3),
Ni ²⁺ (24.1), Cu ²⁺ (23.0), Al ³⁺ (4
4.1), Sn ⁴⁺ (48.2), Zn ²⁺ (22.7),
Cr ²⁺ (23.0), Mo ³⁺ (36.1) and the like, of which metal ions having a hydration index of less than 15 such as Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ and Cs ⁺ It is difficult to obtain sufficient hygroscopicity even by increasing the amount of metal ions, and as a result, the performance of the polyamide fiber is deteriorated, which is not preferable.

Further, in order to obtain sufficient hygroscopicity, a metal ion having a hydration index of 15 or more is added in an amount of 0.05 per 1 kg of fiber weight.
It is essential to contain more than gram ions. 0.
When it is less than 05 gram ion, the hygroscopic effect is low regardless of the metal ion species having a high hydration index, and in order to obtain sufficient hygroscopicity, a large amount of the condensate must be blended with the polyamide. However, the original excellent physical properties of polyamide will be impaired.

In the present invention, the method for introducing the metal ion having a high hydration index into the polyamide fiber is a condensate obtained by reacting a sulfonate compound previously converted to a salt of a metal having a high hydration index with polyoxyalkylene glycol. Is added in the latter stage of the polymerization reaction, immediately before spinning, or during spinning. Further, a condensate of a sulfonate compound of a metal salt having a low hydration index and a polyoxyalkylene glycol is synthesized in advance, blended with polyamide to form a fiber, and the metal element in the sulfonate compound is a metal salt having a high hydration index. There is also a method of replacing with treating with the solution of The hygroscopic polyamide fiber of the present invention can be produced by any method and is not particularly limited.

As a method of substituting the metal in the sulfonate compound in the subsequent step after fiber formation, a general processing method, for example, a water-soluble metal salt of a metal having a high hydration index in the dyeing step is dissolved in a dye liquor. By doing so, it is possible to carry out the replacement while dyeing, and it is also possible to carry out the replacement by treating with an aqueous solution of a metal salt in the finishing step after dyeing. In addition, the pad steam method and the like can be applied, but the processing method is not particularly limited.

The heating temperature and the processing time during the post-processing are 130
A range of 30 minutes at 80 ° C to 180 minutes at 80 ° C is suitable.
If the temperature is 130 ° C or higher, a part of the copolyamide is hydrolyzed, which is not preferable. On the other hand, if the temperature is 80 ° C. or lower, the substitution of the metal does not reach saturation even if the treatment time is extended beyond 180 ° C. On the other hand, as the water-soluble metal salt, any of inorganic salts, carboxylates, and organic acid salts such as succinate can be used as long as they are water-soluble.

Specific examples include aluminum sulfate, manganese sulfate, zinc nitrate, cobalt acetate, magnesium acetate and chromium nitrate. In addition, the content of the condensate used in the hygroscopic polyamide fiber of the present invention is 0.
It is preferably contained in an amount of 05 mol or more and 0.7 mol or less. Furthermore, 0.15 mol or more and 0.5 mol or less are particularly preferable.

If desired, various additives such as dyes, pigments, fillers, lubricants, reinforcing agents, flame retardants, stabilizers and ultraviolet absorbers may be added to the hygroscopic polyamide fiber of the present invention. Good.

[0025]

EXAMPLES The present invention will be described in detail below with reference to examples, but these do not limit the scope of the present invention. In the examples,% means% by weight, and parts means parts by weight. In addition,
Moisture absorption rate (hereinafter abbreviated as MR) is 20 ° C, relative humidity 65
% Thermo-hygrostat (Tabay Espec, PR-2G)
It is a value obtained by leaving it to a constant weight and calculated by the following formula.

MR = (weight of hygroscopic fiber-weight of absolutely dry fiber) /
Absolute dry fiber weight × 100 Further, the post-processing conditions were as follows. 1) 2g / liter of Score Roll 400 from Smelting Kao Co., Ltd.,
A bath ratio of 1: 200 was performed at 60 ° C. for 30 minutes, and then rinsed with running water for 30 minutes. 2) Kanol Mill manufactured by Nippon Kayaku Co., Ltd. for dyeing long fibers
2% of ing Blue2RW was added to adjust the staining solution at pH 4. The sample was put at 40 ° C., heated at 2 ° C./minute, and dyed at 100 ° C. for 60 minutes.

[0027]

Example 1 68 parts of polyethylene glycol having an average molecular weight of 1000, 35% ethylene glycol solution of 3,5-bis (hydroxylethoxy) sulfoisophthalate sodium salt (however, reaction of 70% hydroxyethoxy group and 30% carboxymethoxy group) Mixture) 756 parts, 108 parts of triethylene glycol having a molecular weight of 150, 0.8 part of lithium acetate dihydrate, 1.2 parts of tetraisopropyl titanate are charged into a polymerization machine and heated at 220 ° C. under a nitrogen flow for 2 hours. After stirring, raise the temperature to 240 ° C,
The pressure was reduced over 45 minutes and finally to 0.2 mmHg.

After keeping this state for 15 minutes, the polymerization machine was returned to normal pressure with nitrogen, and 44 parts of trimellitic anhydride was added to 1
After reacting for 5 minutes, it was discharged from the polymerization machine to obtain a viscous condensate (hereinafter abbreviated as SP1). 10 parts of the obtained SP1 was blended with nylon 6 having an ηr of 2.45 (1 g polymer / 95.5% sulfuric acid 100 ml, 25 ° C.) 90 parts at the time of melt molding, and spun and stretched by a usual method to obtain 100. A long fiber of denier 24 filament was obtained.

The obtained fiber was refined and dyed, and then treated in an aqueous solution containing the same amount of magnesium acetate as sodium contained in the fiber while boiling for 2 hours. Sodium in the obtained fiber was replaced with magnesium having a hydration index of 23.3, and MR was 7.0%. Also, the obtained SP
After dissolving 1 in pure water, H ⁺ type Dowex 5 from Muromachi Kagaku
N in SP1 is passed through a glass column filled with 0W-X8.
The a ⁺ was ion-exchanged with H ⁺ . Mg (OH) ₂ was added to this H ⁺ type SP1 aqueous solution to neutralize and ion-exchange with Mg ⁺ . The obtained aqueous solution was dried under reduced pressure to obtain a Mg ²⁺ type condensate (hereinafter abbreviated as SP3). The MR of the obtained SP3 itself was 23.8%.

[0030]

[Example 2] 10 parts of SP1 used in Example 1 had an ηr of 2.50 (lg polymer / 95.5% sulfuric acid 100 ml,
(25 ° C) 10 parts of nylon 66 was blended at the time of melt molding,
Long fibers having 100 denier 24 filaments were obtained in the same manner as in Example 1. The MR of the fiber obtained by refining and dyeing the obtained fiber and treating with an aqueous solution of zinc sulfate was 6.5%.

[0031]

Comparative Example 1 10 parts of the condensate SP1 used in Example 1 was added to 90 parts of nylon 6 used in Example 1 for spinning,
It was stretched. The fiber after refining and dyeing remained sodium having a hydration index of 8.6, and its MR was 5.7% as shown in Table 1.

[0032]

Comparative Example 2 10 parts of the condensate SP1 used in Example 1 was added to 90 parts of each of the nylon 66 used in Example 2 and spun and stretched. The fiber after refining and dyeing has a hydration index of 8.6.
Remained sodium and its MR was 5.5% as shown in Table 1.

[0033]

Comparative Example 3 In the reaction of Example 1, 0.2 mmHg
After the pressure was reduced to 15 minutes and kept for 15 minutes, the polymerization machine was returned to normal pressure with nitrogen, and the same reaction as in Example 1 was carried out except that 45 parts of trimellitic anhydride was added and reacted for 15 minutes. A viscous condensate (hereinafter abbreviated as SP2) was obtained.

20 parts of the obtained SP2 had an ηr of 2.45.
(1 g polymer / 95.5% sulfuric acid 100 ml, 25 ° C.)
80 parts of nylon 6 was blended at the time of melt molding, spun and stretched by a usual method to obtain 100 denier 24 filament long fibers. MR after refining and dyeing the obtained long fibers
Was 5.1%, which was 1.9% lower than that of Example 1.

[0035]

Comparative Example 4 788 parts of polyoxyethylene glycol having an average molecular weight of 1000 and a 35% ethylene glycol solution of 3,5-bis (hydroxylethoxy) sulfoisophthalate sodium salt (provided that hydroxyethoxy group 70
%, Reaction mixture of 30% carboxymethoxy groups) 756
Parts, 0.8 parts of lithium acetate dihydrate and 1.2 parts of tetraisopropyl titanate were charged in a polymerization machine and reacted in the same manner as in Example 1 to give a light yellow viscous condensate (hereinafter SP).
3). The obtained SP3 was melted at 123 ° C. The MR of the condensate obtained by subjecting the obtained SP4 to ion exchange with Mg ⁺ in the same manner as in Example 1 was 9.2%.

[0036]

Comparative Example 5 In the reaction of Example 1, 0.2 mmHg
After the pressure was reduced to 15 minutes and kept for 15 minutes, the polymerization machine was returned to normal pressure with nitrogen, 44 parts of trimellitic anhydride was added, and the reaction was carried out in the same manner as in Example 1 except that the reaction was carried out for 15 minutes. A condensate (hereinafter abbreviated as SP4) was obtained.

2 parts of the obtained SP4 was blended with 98 parts of nylon 6 used in Example 2 at the time of melt molding to obtain a 100 denier 24 filament long fiber. The obtained fiber was treated in the same manner as in Example 1, and the MR was 5.2%.

[0038]

Comparative Example 6 Triethylene glycol 1 having a molecular weight of 150
08 parts, polyethylene glycol 2 with an average molecular weight of 400
7 parts, 3,5-bis (hydroxylethoxy) sulfoisophthalate sodium salt 35% ethylene glycol solution (however, reaction mixture of 70% hydroxyethoxy group and 30% carboxymethoxy group) 756 parts, lithium acetate dihydrate 0 .8 parts, tetraisopropyl titanate 1.
Two parts were charged into a polymerization machine and reacted in the same manner as in Example 1 to obtain a light yellow viscous condensate (hereinafter abbreviated as SP5).
The obtained SP5 was melted at 110 ° C. Also, SP6
M of the condensate obtained by ion-exchange with Mg ⁺ in the same manner as in Example 1.
R was 18.3%.

[0039]

[Comparative Example 7] When melt-spinning was carried out using SP1 in Example 1 at 40% (0.85 mol / kg of sulfonic acid group), the spinnability was very poor and fibers could not be collected.

[0040]

[Table 1]

[0041]

The hygroscopic polyamide fiber of the present invention is superior in durability and higher in hygroscopicity as compared with the conventional ones.

Claims (1)

[Claims] 1. A condensate of two or more kinds of polyoxyalkylene glycols represented by the formula (1) having different average molecular weights and a sulfonate compound represented by the formula (2), wherein the terminal group of the condensate is a carboxyl group. The amount of the sulfonic acid group converted into the base is 0.05 mol or more per 1 kg of the fiber, and the sulfonic acid group is more than 0.1.
A hygroscopic polyamide fiber containing 7 mol or less and M in the formula (2) being a metal having a hydration index of 15 or more. [Chemical 1]