JPS62268818A - Production of conjugate fiber - Google Patents

Abstract

PURPOSE:To obtain conjugate fibers having improved crimp developing power, etc., and peeling resistance, by arranging a polymer blend containing a thermoplastic polyurethane elastomer and a specific component and polycapramide to be eccentric in the fiber cross section, spinning and drawing the polymers. CONSTITUTION:(A) A block copolymer selected from a polyester.polyether, polyester.polyester and polyether ester is preferably kneaded with (B) a polyisocyanate compound and formed into pellets. The resultant blend is then melt blended with (C) a thermoplastic polyurethane elastomer and then subjected to conjugate spinning with (D) separately melted polycapramide so as to arrange in an eccentric form, e.g. side-by-side type or eccentric sheath-core type, etc. The obtained yarns are then aged, preferably for >=12Hr and drawn to afford the aimed conjugate fibers. The dissolving reduction ratio of the component (C) in the undrawn yarns to DMF is preferably <=80wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a self-crimping composite C fiber made of polycapramide and polyurethane elastomer.

(Prior Art) It is known that Filasoft, in which polyamide and polyurethane elastomer are aligned qj centrically within the cross section of a single filament, has a high degree of crimpability.These composite filaments As the polyamide component, polycapramide, homopolyamide and copolyamide with a melting point of 140°C to 280''C are used, while the polyurethane elastomer is a polyether type using polyalkylene oxide glycol, polytetramethylene glycol, etc. as the polyol. It uses polyurethane, polyester polyurethane made of dibasic acid and glycol, or polycaprolactone polyurethane obtained by ring-opening polymerization of C-caprolactone (Japanese Patent Publication No. 47
-18052 Publication, Special Publication No. 49-48498,
Special Publication No. 49-10288, Special Publication No. 55-8672
5@Publication). However, filaments made by composite spinning of these polymers have insufficient adhesive strength between both components.

There is a drawback that both components peel off due to bending or friction during the product manufacturing process or when the product is worn, resulting in a decrease in performance.

Composite filaments with increased adhesion of both components and improved peel resistance include polycarboxylic acid polycarbonate polyurethane, mixtures or block copolymers of polycarbonate urethane and polycaprolactone urethane, and polycarbonate urethane. Eccentric core-sheath type composite filaments are known in which the core component is a mixture or block copolymer of urethane and polyether urethane or polyester urethane, and the sheath component is polycapramide (Japanese Patent Publication No. 56-22569, Japanese Patent Publication No. 55-22570, Japanese Patent Publication No. 34369, Japanese Patent Publication No. 57-84
Publication No. 870). These composite yarns use polycarbonate ester, which has a strong affinity for the amide bond of polycapramide, as the main component of the soft segment, increasing the adhesive strength between the polycapramide and polyurethane components, and at the same time, forming an eccentric core-sheath in which the polycapramide wraps around the polyurethane. This structure increases the adhesion area of both components and improves their peeling resistance.

However, although these composite yarns have improved peeling resistance of both components, they have the disadvantage that they are inferior in crimp development ability and stretch recovery properties of crimps compared to ordinary side-by-side type composite yarns. In other words, these composite yarns exhibit spiral crimp with the polyurethane component on the inside because the shrinkage force of the polyurethane component is greater than that of polycapramide, but since the new surface shape has an eccentric core-sheath structure, the polyurethane component The thin polycapramide skin that envelops the polyurethane component blocks the shrinkage force of the polyurethane component, resulting in poor crimp performance.

Further, these composite yarns are usually made into face yarns by a method of melt-spinning and then stretching to give shrinkage force to the polyurethane component, but the composite yarns after stretching exhibit a significantly high linear shrinkage rate. For this reason, it has the drawback that it shrinks significantly during the process of directly processing the knitted fabric, such as embossed metal, dyeing, and finishing, making it impossible to obtain a satisfactory product size. To solve these problems, it is common to subject the drawn composite filament to a relaxation heat treatment at a temperature of 100 to 180° C. to reduce linear shrinkage, and then weave and knit the filament, and then dye and color the filament. However, even though these composite filaments have txt crimp development properties and crimp stretch recovery properties after spinning and drawing, their performance deteriorates significantly after the above-mentioned relaxation heat treatment. There is a drawback. The reason for the decrease in performance due to the relaxing heat treatment is thought to be that the shrinkage force of the polyurethane component is easily relaxed by heat, so that only a small amount of shrinkage force remains after the relaxing heat treatment.

(Problems to be Solved by the Invention) The object of the present invention is to solve the problem that not only the peeling resistance of polycapramide and polyurethane elastomer is poor, but also sufficient crimp development force and crimp resistance even after relaxation heat treatment. An object of the present invention is to provide a method for producing a fiber having stretch recovery properties.

(Means for solving the problem) That is, the present invention comprises a block copolymer selected from the group of polyester/polyether, polyester/polyester, and polyester/polyether ester, a polyisocyanate compound, a thermoplastic polyurethane elastomer, and a polyisocyanate compound. A method for producing a self-crimping conjugate fiber includes melt-mixing a polymer mixture of 1 and polycapramide by eccentrically arranging and bonding the same in the fiber cross section, melt-spinning, and then drawing.

The block copolymer used in the present invention is polyester.
It is a block copolymer selected from the group of polyether, polyester/polyester, and polyester/polyetherester. For example, polyester/polyether block copolymers are elastic bodies that contain almost no active hydrogen that reacts with isocyanate groups, and are characterized by being able to stably maintain the activity of isocyanate groups even after mixing with polyisocyanate compounds. . As a polyester/polyether block copolymer suitable for the present invention, dimethyl terephthalate is transesterified with 1,4-butanediol, and then poly(
An elastomer obtained by polycondensation reaction of (tetramethylene oxide) glycol, which includes a polymer with a melting point of 180°C or less.A block copolymer with a melting point of 180°C or less is a thermoplastic polyurethane elastomer. It is preferred that the mixture obtained by mixing the polyisocyanate compound and the thermoplastic polyurethane have good compatibility and can be easily melt-mixed using a known mixing device.

The polyisocyanate compounds used in the method of the present invention are compounds having two or more isocyanate groups in the molecule, such as diisocyanate compounds, carbon-imide-modified polyisocyanate compounds, and allophanate compounds in which the isocyanate groups are blocked with alkoxy groups or phenoxy groups. Among the compounds forming the group, those having molecules @400 or less are preferable.

The thermoplastic polyurethane elastomer suitable for spinning in the method of the present invention is a polyurethane elastomer having a hardness of 90 to 100 measured according to the Sitzer hardness A measurement standard JIS K2SO3, such as polyester polyurethane, polycaprolactone polyurethane, polycarbonate polyurethane, etc. It is. A polyurethane elastomer having a hardness of 90 or less is not preferable because it cannot be stably spun due to the balance of melt viscosity with polycapramide. In addition, polyurethane elastic bodies with hardness exceeding 100 tend to have poor elastic recovery rate,
Undesirable.

The polycapramide used in the present invention is 98% saccharic acid 100%
Polymers having a relative viscosity in the range of 2.0 to 2.60 when dissolved in 1 ml of sample at 25°C are preferred.

Polycapramide polymers with a relative viscosity of less than 2.0 frequently break during composite spinning. Alternatively, the obtained composite filament has low strength and elongation, which is not preferred because it is not practical. On the other hand, a polycapramide polymer having a relative viscosity of more than 2.60 is unsuitable because its melt viscosity is too high and cannot be stably spun with a polyurethane elastomer. In particular, a composite filament made of cabramid having a relative viscosity of 2.0 to 2.60 has excellent strength and elongation characteristics and abrasion resistance, and is therefore a preferred composite yarn.

In the present invention, a block copolymer and a polyisocyanate compound are kneaded in advance at a temperature higher than the softening point of the block copolymer using a Parbury mixer, an extruder, a kneader, a mixing roller, etc., and then cooled. , and then pulverized or pelletized using a pulverizer. Next, the mixture and a thermoplastic polyurethane elastomer are fused together,
Separately, polycapramide, which has been melted in a bath, is spun using a conventional composite spinning method such that the composite material is eccentrically arranged and joined, such as a side-by-side type or an eccentric core-sheath type.

Methods for mixing the mixture into the polyurethane elastomer include a method in which the solid polyurethane elastomer is mixed and then fed into an extruder and kneaded, or a method in which the mixture is added to a molten polyurethane elastomer and mixed.

The amount of polyisocyanate compound mixed with respect to the block copolymer is usually preferably 5 to 50% by weight. The amount of the mixture to be mixed into the thermoplastic polyurethane elastomer is 0.3 to 2% of the amount of isocyanate groups (of the polyisocyanate compound) in the mixture relative to the thermoplastic polyurethane elastomer.
．． 0% by weight is desirable. When the amount is less than 0.8% by weight, the effect of the present invention is not sufficient; on the other hand, 2. If it exceeds Oi%, the melt viscosity of the polyurethane elastomer decreases, and there is a tendency that stable spinning becomes impossible.

In the method of the present invention, the undrawn yarn that has been melt-spun and wound up is
For example, it is desirable to stretch the film after aging at room temperature for 12 hours or more. During this aging time, the polyisocyanate compound mixed in the polyurethane elastomer reacts with the urethane bonds in the polyurethane elastomer to form a crosslinked structure.

The progress of the crosslinking reaction by the polyisocyanate compound of the polyurethane elastomer forming the composite fiber is as follows:
The solubility in solvents decreases as the crosslinking reaction progresses. In the method of the present invention, the dissolution reduction rate of the polyurethane elastomer component of the undrawn yarn in dimethylformamide (hereinafter referred to as DMF) is 80%.
It is desirable to draw the undrawn yarn whose weight is 2% or less.

This is because a composite fiber having excellent peeling resistance and excellent crimpability after relaxation heat treatment can thereby be obtained, and the object of the present invention can be best achieved. In other words, it is desirable that the cross-reaction is carried out in the undrawn state, and the cross-reaction (a
As the reaction progresses, the shrinkage force of the polyurethane component decreases and P
! This is disadvantageous to improving compression performance.

As a method of accelerating the crosslinking reaction rate in undrawn yarn, there is a method of heat treatment at high temperature. For example, in heat treatment at 100°C, the dissolution rate of the polyurethane component in DMF is reduced by 80% by weight or less in a treatment time of 1 to 2 hours. However, at this level, there is a drawback that the polycapramide component is deteriorated by heat and the drawability is significantly reduced. The most desirable aging temperature is room temperature, but when aging is performed at a high temperature, the temperature is preferably 70° C. or lower.

In the method of the present invention, D of the polyurethane component of the undrawn yarn
The commonly understood reduction rate for MF is that after collecting composite fiber 102 and measuring its weight, it is heated at 80°C at a bath ratio of 1:60.
After immersing the composite yarn in DMF for 1 hour with stirring to dissolve the polyurethane component, it was thoroughly washed with water and air-dried, the weight was measured, and the weight was calculated using the following formula.

WO: Weight of yarn after DMF treatment W1: DM? After treatment a: The overlapping ratio of polyurethane components in the composite yarn DMF is a good solvent for the polyurethane elastic body 1, and almost all of the thermoplastic polyurethane elastic body is dissolved. However, in the present invention, since the polyurethane elastomer component has a crosslinked structure, its solubility in DMF is reduced. The rate of dissolution reduction in DMF is a measure of the crosslink density in the polyurethane elastomer, and the higher the crosslink density, the greater the rate of decrease.

(Effects of the Invention) The composite fiber obtained by the method of the present invention has excellent adhesion between the polycapramide component and the polyurethane elastomer component, and even when processed into stockings or the like and worn, the two components do not separate. In addition, it has excellent crimp development ability and crimp stretch recovery, making it suitable for spinning and
Even when subjected to relaxation heat treatment after stretching, sufficient crimp properties are maintained.

(Example) A more detailed explanation will be given below using examples.

In addition, "linear shrinkage rate", "crippling rate", and
``Crimp elongation recovery rate'' and ``peeling resistance'' are values measured by the following method.

(1) Linear shrinkage rate and crimp stretch recovery rate composite 11fil
, 000 denier, apply a load of 0.2 f/d, and measure the length io after 1 minute. Next 0.2
A crimp development treatment is performed in aqueous humor for 10 minutes while applying a load of my/ei, and then natural air drying is performed under that load day and night. Next, in order to remove the entanglement between the fibers, 0.2 f/
Add the cylindrical mold d and leave it for 1 minute. Remove the load of 0.29/d, measure the length 11 after 2 hours, and re-apply 0.2/d.
After adding a load of f/d and measuring the length 12 after 1 minute, the load of 0.217/d was removed and the recovery length of 1 minute step was 1.
8 is measured and calculated using the formula below.

(2) Crimp development rate: Take a fiber equivalent to too much denier into a skein and 0.2f
Apply the F/d load and measure the length 14 after 1 minute.

Next, 1 ζ 1 my/d Fi 晦 7 trigrams in aqueous humor 10
After carrying out crimp development treatment for 1 minute and natural air drying under -fi night 1, the length 16 was measured and calculated using the following formula.

Crimp development rate (%) = -X 100 (3) Peeling resistance Using a Schieffer abrasion tester (manufactured by Shimadzu Corporation), the composite fiber was dyed in a cylindrical manner and finely dyed to prepare a test cloth, and I Ky was applied to the test cloth.
After rubbing the composite fibers aooo times and 5,000 times under a load of 1, peeling of the composite fibers was observed using a microscope.

○: No peeling, △: Slight peeling, X: Peeling Example 1 Dimethyl terephthalate (hereinafter referred to as DMT) and 1,4
-Butanediol (hereinafter referred to as 1.4-BG) and polytetramethylene glycol (hereinafter referred to as PTMG) with a number average molecular weight of ztaoo are subjected to a polycondensation reaction according to a conventional method, and P'
Melting point 1 where 5011% l'MG is copolymerized in the polymer
A polyester/polyether block copolymer (1) at 56°C was obtained.

80 parts of 4,4-diphenylmethane diisocyanate (hereinafter referred to as MDI) was added to 70 parts of the block copolymer to obtain Tsuku copolymer pellets (I') at a temperature of 160 to 170°C. contains 10% by weight of isocyanate groups.)

Thermoplastic polycaprolactone-based polyurethane elastomer pellets with a hardness of 95 consisting of polycaprolactone diol with a number average molecular weight of 11500, MDI, and 1.4-BG 10
0 part and 10 m of the mixture (1') in the form of pellets, melt-mixed at 230°C, and then using a known eccentric core-sheath type composite spinneret, the polyurethane elastomer was the core component and the relative viscosity was 2. .45 polycapramide is joined at a joining ratio of 50:50 so that it becomes the sheath component, and the single yarn denier is 70 d.
The undrawn yarn was wound up at 600 m/min. The amount of isocyanate groups added to the polyurethane elastomer was 1% by weight. The undrawn yarn that was wound up was immediately heated to 25'C, 6
The undrawn yarn was brought into a temperature-controlled room at 5% RH, and the rate of decrease in dissolution of the undrawn yarn in DMF was measured 8 hours, 6 hours, 12 hours, 24 hours, 48 hours, and 72 hours after the completion of winding. In addition, a stretching continuous relaxation heat treatment machine with a 1-m-long hollow heater installed under the stretching zone was used, and the conditions were a stretching speed of 500 m/min, a stretching table ratio of 150, a relaxation rate of 50%, and a temperature of the hollow heater of 150°C. The above-mentioned undrawn yarn is subjected to a stretching relaxation heat treatment at each of the above-mentioned aging times to produce stretching relaxation heat treatment systems A, B, and C1D1 with different aging times for the undrawn yarn.
I got E and F. .

Next, as a comparative example, the soft segment component had a molecular weight of 1
500 polycarbonate ester 60 parts and molecule ff11500
A polycarbonate/polycaprolactone-based thermoplastic polyurethane elastomer with a hardness of 95, consisting of 40 parts of polycaprolactone with hard segments of MDI and 1.4-EG, and polycapramide with a relative viscosity of 2.25 were used. Using an eccentric core-sheath type composite nozzle, the polyurethane elastic material was used as a core component and the polycapramide was used as a sheath component at a joining ratio of 50:50, and the undrawn yarn of 70 denier/2 filaments was wound at 600 m/min. Ta. Then 48
After time aging, using the stretching continuous relaxation heat treatment machine, A
Comparative sample G was obtained by stretching and relaxing heat treatment under the same conditions as ~E. The results of evaluating the crimp characteristics and #J abrasion properties of composite fibers A to G are shown in Table 1.

As can be seen from Table 1, Comparative Example G has a load of 80 kg under a load of I kg.
Although peeling occurred after only 00 times of rubbing, samples A to F obtained by the method of the present invention have excellent peeling resistance.

Furthermore, the solubility of the polyurethane component in DMF in the undrawn yarn decreases with aging time, and after 12 hours of aging, the solubility in DMF decreases to 80! i! 1%, which reduces solubility in DMF and improves crimp properties and peeling resistance. In particular, aria stretched with a dissolution reduction rate of 80% by weight or less in DMIF had good crimp properties and peeling resistance.

Example 2 DMT, dimethyl isophthalic acid, polytetramethylene glycol diol with a molecular weight of 1100, and 1.4-EG
using the respective preparation ratio (weight) 100:55
:108 :100.100:48 :50 :90,
Zoo: O: 80 Polycondensation was performed according to a conventional method at a ratio of 0 to 0, and the melting points were 165°C, 178°C, and 198°C, respectively.
Polyester/polyether block copolymer (l
I), ■, and (g) were obtained.

30 parts of MDI was mixed with 70 parts of each polyester/polyether block copolymer, and then 170~
Using an extruder set at 205°C, the mixture was sufficiently kneaded and then cut using the air cutting method to obtain an MDI of 80 weight 2.
% mixed polyester/polyether block copolymer (1'), (厘'), (■ obtained ((1'), (
10M each for III') and (■')! Contains 1% isocyanate groups. ).

Next, in Example 1 (instead of white (■'), (I')
, (ff') was used for composite spinning under the same conditions as in Example 1.

Regarding the spinning winding situation, when (■') was used, there was a slight increase in spun yarn breakage (because the melting point of (IV') exceeds 180°C, the compatibility with the polyurethane elastomer is poor; The discharge condition was also somewhat unstable.)
All were good. Next, the undrawn yarn was aged for 2 days, and then subjected to drawing and relaxation heat treatment in the same manner as in Example 1.

All of the obtained composite mls had good crimp properties and peeling resistance.

Example 8 After reacting polybutylene glycol diol with a number average molecular fi 1800 and MDI at a molar ratio of 1:8.5,
1.4-BG in an amount that makes the ratio of NCO and OH 1.08
were reacted to obtain a thermoplastic polyurethane elastomer having polybutylene adipate as a soft segment.

The polyester/polyether block copolymer ([)12 with a melting point of 178°C used in Example 2: A mixture (■') containing 30% by weight of MDI was added to 100 parts of the polyurethane elastomer at 1 part, 8 parts, and 5 parts. After mixing 10 parts, 18 parts, and 25 parts, they were melt-mixed in an extruder set at 285"C, and then polycapramide with a relative viscosity of 2.85 melted at 250"C and heated to 230 °C. A side-by-side composite spinneret with a splicing ratio of 50:50
By joining at a ratio of 6007 to make a composite filament with a single denier of 40d! I finished it in / minute. Under the above mixing conditions, the amounts of isocyanate groups added to the thermoplastic polyurethane elastomer are 0.1% by weight, 0.8% by weight, 0.5% by weight, 1.0% by weight, and 1.8% by weight, respectively. %, 2.
It was 5% by weight. The spinning winding situation under each condition shows that the amount of isocyanate groups added is 2.5Mf! %, the melt viscosity of the polyurethane elastomer component decreased and the number of spun yarn breakages increased slightly, but otherwise all conditions were good.

After aging the wound undrawn yarn in a room at 30°C and 170% RE for 2 days, it was treated under the same conditions as in Example 1 using the stretching continuous relaxation heat treatment mallet of Example 1 to obtain relaxation heat treatment system H.
, I, J, K.

I got L and M. The evaluation results of these composite fibers are shown in Table 2.

As is clear from Table 2, fibers in which the amount of isocyanate groups added to the polyurethane elastomer was 0.3 to 2.5% by weight showed excellent crimp properties and peeling resistance, but 0.1% by weight The improvement effect was somewhat insufficient for the kiA fibers.

Claims (6)

[Claims] (1) A polymer mixture of a block copolymer selected from the group of polyester/polyether, polyester/polyester, and polyester/polyether ester, a polyisocyanate compound, and a thermoplastic polyurethane elastomer, and polycapramide in a fiber cross section A method for producing a self-crimping conjugate fiber, which comprises eccentrically arranging and joining, melt-spinning, and then drawing. (2) The method according to claim 1, wherein the block copolymer is a polyester/polyether block copolymer whose main components are polytetramethylene terephthalate and poly(tetramethylene oxide) glycol. (3) The method according to claim 1, wherein the block copolymer has a melting point of 180°C or less. (4) The method according to claim 1, wherein the polyisocyanate compound is mixed with the thermoplastic polyurethane elastomer in an amount of 0.3 to 2.0% by weight based on the amount of isocyanate groups. (5) The method according to claim 1, wherein the block copolymer and the polyisocyanate compound are melt-mixed in advance, and then the mixture and the thermoplastic polyurethane elastomer are melt-mixed. (6) Claim 1, in which the undrawn yarn obtained by melt spinning is stretched after the dissolution reduction rate in dimethylformamide of the thermoplastic polyurethane elastomer component of the undrawn yarn obtained by melt spinning is reduced to 80% by weight or less. the method of.