JP2622175B2 - Heterogeneously mixed conjugate fiber and method for producing the same - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a composite fiber of a saponified ethylene-vinyl acetate copolymer and polyester, which is excellent in functionality and aesthetics, and a method for producing the same. .

(Conventional technology) Polyester fiber has excellent strength elasticity, abrasion resistance, chemical resistance, weather resistance, form stability, etc. not found in natural fibers.
Due to its excellent general-purpose properties, it is produced and consumed in extremely large quantities as fiber. However, on the other hand, the use of high-quality fabrics and garments in terms of the aesthetics and luxuriousness of natural fibers is notwithstanding many efforts in terms of polyester color, fiber morphology, and yarn structure. There is a side that does not work. On the other hand, the darkening of the white fabric due to repeated washing is a problem of recontamination, which is inferior to the function of cotton. The problem remains. Although various studies have been made on the problem of such polyester fibers in various fields, it is difficult to solve the above-mentioned problems with polyester fibers having no hydrophilic group or having only a very small amount of copolymerized or modified molecular terminals. It turned out to be insufficient.
On the other hand, when a large amount of a hydrophilic group is introduced, the intrinsic properties of the fiber base material are impaired and cannot be put to practical use, and it has also been found that polymer modification such as simple copolymerization has its limitations.

As a result of studying why natural fibers such as cotton, silk, and wool have excellent feeling, aesthetics, and functionality against dirt, water is used as a medium because all natural fibers have hydrophilic groups. It has become clear that it has a characteristic in the processing that it does.

Each natural fiber swells when it contains water, and the apparent thickness of one fiber becomes nearly 30% thicker, while the fiber slightly deforms when swollen (wool is crimped by a bilateral structure, cotton is twisted by convolution, twisted by silk) The yarn becomes even thicker due to distortion, and the texture and stitch are bent and fixed. Thereafter, when the fabric is dried, the apparent thickness at the time of swelling is reduced, so that voids between the fibers are left, and the weaves and stitches are fixed. Therefore, the contact pressure between fibers or crossed yarns is small, the restraining force is hard to work in the process of bending, shearing, tensile deformation and recovery of the fabric, and the hysteresis loss is small, so it has good resilience and it is a lively fabric. It became clear that there were many.

On the other hand, it has been found that problems such as oily soiling, darkening due to washing recontamination, and disperse dye sublimation transfer staining can be remarkably improved by forming the surface of the polyester fiber with a hydrophilic polymer.

The present inventors have focused on the application of the saponified ethylene-vinyl acetate copolymer to polyester fibers based on the above points. That is, the saponified ethylene-vinyl acetate copolymer is a water-based swelling polymer and has a hydrophilic group, so that the problem of oily stains generated on the polyester fibers and darkening due to washing recontamination can be solved, and disperse dye sublimation transfer. Therefore, the present invention pursued and clarified what kind of fiber should be used from both polymers in order to obtain a fiber utilizing the properties of polyester while utilizing this property. It is.

(Means for Solving the Problem) Conventionally, there has been known a molded product obtained by uniformly mixing an ethylene / vinyl alcohol-based resin as a hygroscopic polymer for the purpose of improving the chargeability of polyester (Japanese Patent Publication No. 46-5223).

However, in the case of fibers, if the ethylene vinyl alcohol component is sufficiently mixed with the polyester component to form a uniform blend structure, the fabric does not have a good texture because it lacks the swelling of the woven or knitted fabric compared to the non-uniformly mixed fibers. .
As a result of analyzing the reason why such a behavior was caused, it was found that the uniformly blended structural fibers shrink uniformly when immersed in high-temperature hot water, but the fibers did not deform much.

On the other hand, it was found that when the fibers mixed unevenly were immersed in high-temperature hot water, some parts were bent and some parts were twisted, causing slight deformation at various places. Since the ethylene vinyl alcohol copolymer swelling through water is unevenly distributed in the fiber cross section, the swelling strain due to swelling with hot water locally deforms the straight fiber, which gives the fiber a good swelling and taste. It is thought that this very closely resembled the behavior of the natural fibers described above, which causes micro-deformation strain upon swelling.

That is, the present invention has an ethylene content of 30 to 70 mol% and a degree of saponification of 95% or more, and is based on JIS K 6730-1977.
Saponified ethylene vinyl acetate copolymer (A) having a melt index of 20 or less under a load of 2160 g at 90 ° C
(Hereafter, ethylene vinyl alcohol copolymer or EV
AL), and a thermoplastic polyester (B) containing polyethylene terephthalate and / or polybutylene terephthalate as a main component are separately melt-extruded, and the weight ratio is determined using a static mixer immediately before reaching a spinning nozzle. a: B = 5: 95~40: 60 range, the division number is 2 ^{3-2 15} become so mixed heterogeneous, thereafter, formed by fiberizing extruded from a spinning nozzle the mixture through a split thinning member It is a fiber, and is a conjugate fiber whose fiber cross-sectional shape is a non-uniform mixed form. That is, it is a non-uniformly mixed conjugate fiber in which the A component is distributed in an island state in the fiber cross section, and a circle having a diameter of at least 1/20 of the fiber diameter can be drawn in the B component region where the A component does not exist.

The distribution state of the A and B components in the fiber cross section is determined by a transmission optical microscope photograph. FIGS. 1 to 4 are reproductions of the photograph, and FIGS. 1, 2, and 3 illustrate examples of the present invention, and FIG. 4 illustrates a comparative example of uniform mixing. .
In the cross-sectional view, black dots indicate the ethylene vinyl alcohol copolymer (A) component, and white portions other than the black dot indicate the polyester (B) component.

In the composite fiber of the present invention, in the fiber cross section,
The A component is distributed in a thinned island state, and the distribution is uneven, so that the sea portion corresponding to the island portion, that is, the B component is also unevenly distributed in the fiber cross section. The feature is that there is. In order to express the non-uniform distribution or uneven distribution of the A component or the B component, in the present invention, in the B component region where the A component does not exist in the fiber cross section, the diameter (L) of at least 1/20 of the fiber diameter D is used. ) Is determined based on whether or not the circle can be drawn.
Here, the fiber diameter D is the diameter of the fiber when the fiber cross section is circular as shown in FIGS. 1 to 4, and the diameter of the circumscribed circle when the fiber cross section is irregular.

In the fiber of the present invention, the size of the diameter L of the apparent circle existing in the B component region where the A component does not exist is at least D / 20.
And more preferably D / 10 to D / 2. This cannot be said uniformly because it varies depending on the mixing ratio of the component A and the component B. However, when L is less than D / 20, there is not much difference from the uniformly mixed fiber and the effect is weakened. The B component region in which the apparent circle of D / 20 or more exists is not specified as one location, and several locations may be localized or unevenly distributed. In addition, the unevenness of the fiber cross section of the heterogeneous mixed conjugate fiber of the present invention is not uniform between the fibers and in the length direction between the fibers, but it is more preferable if L is D / 10 to D / 5. Good and good touch cloth. Fibers having a cross section of such a heterogeneous mixed form are melt-extruded separately from the respective polymers (A) and (B), and are mixed unevenly using a static mixer immediately before reaching a spinning nozzle. Is spun from a spinning nozzle through a dividing and thinning member to be fiberized. And in a static mixer,
Each polymer is A: B = 5: 95~40: 60 mixing ratio (weight ratio) in the range of, and the division number is being unevenly mixed such that 2 ^{3-2 15.}

Due to the B component which is obtained by such a manufacturing method and has a characteristic cross-sectional shape, when the surface erosion treatment on the polyester side is applied by alkali weight reduction processing, the B component has a non-uniform distribution. Is very random and rough. This results in the appearance of a streak-like rough surface or a rough surface shape obtained by wet spinning, which contributes to the improvement of good touch without waxy feeling. In addition, the ethylene-vinyl alcohol copolymer, which cannot be eroded by alkali, is deposited on the epidermis, resulting in a fiber structure as if a thin film of ethylene-vinyl alcohol copolymer was coated on the fiber surface. That is, the component A deposited on the surface prevents oily stains, and can exhibit functions such as prevention of washing re-contamination and prevention of dye transfer. On the other hand, in the case of uniformly mixed fibers, the streaky irregularities after the alkali weight loss is relatively light, so that even if the B component remains on the epidermis, the texture is not so good. Especially in high-temperature and high-pressure dyeing such as in the dyeing process, since the ethylene / vinyl alcohol copolymer has a sufficient swelling effect, the woven or knitted fabric of the non-uniformly mixed fiber has good swelling and stickiness, and also has excellent drapability and silette. Compared with the dough, the uniform mixing does not show such an improving effect.

The thermoplastic polyester referred to in the present invention includes, for example, terephthalic acid, isophthalic acid, naphthalene 2,6-dicarboxylic acid, phthalic acid, α, β- (4-carboxyphenoxy) ethane, 4,4′-dicarboxydiphthalic acid Enil, 5-
Aromatic dicarboxylic acids such as sodium sulfoisophthalic acid or adipic acid, aliphatic dicarboxylic acids such as sebacic acid, or esters thereof, ethylene glycol, diethylene glycol, 1,4-butanediol,
A fiber-forming polyester synthesized from a diol compound such as neopentyl glycol, cyclohexane-1,4-dimethanol, polyethylene glycol, or polytetramethylene glycol, wherein 80 mol% or more of the structural units are 90 mol% Polyesters in which the above is a polyethylene terephthalate unit or a polybutylene terephthalate unit are preferred. Further, the polyester may contain a small amount of additives, fluorescent brighteners, stabilizers, ultraviolet absorbers and the like.

As the EVAL, the one having a high degree of saponification with an ethylene content of 30 to 70 mol% and a degree of saponification of 95% or more is optimal. If the vinyl alcohol component content in EVAL is low, the properties such as hydrophilicity are naturally reduced due to the reduction of hydroxyl groups (OH), and the desired good natural hemp fiber-like feeling cannot be obtained. . Further, when the content of the vinyl alcohol component is too large, the melt moldability decreases, and when mixed with the polyester immediately before spinning to form a fiber, the spinnability becomes poor, single yarns are attached, and the number of yarns is preferably increased. Absent. Further, the heat resistance at 250 ° C. or higher, which is the spinning temperature of polyester, becomes insufficient, which is not suitable. Therefore, those having a high saponification degree EVAL and a vinyl alcohol component content of 30 to 70 mol% are suitable for obtaining the fiber of the present invention.

FIG. 5 shows an example of a cross-sectional photograph of the heterogeneously mixed conjugate fiber of the present invention after the alkali weight reduction processing. A mixture of EVAL having an ethylene content of 48 mol% and a degree of saponification of 99% and polyethylene terephthalate in a weight ratio of 15:85, using a static mixer immediately before reaching the spinning nozzle, followed by a mixture. This is a cross-section of a fiber obtained by spinning from a spinning nozzle through a dividing and thinning member into a fiber, subjecting the fiber to a process such as stretching by an ordinary method, and then subjecting the fiber to an approximately 20% alkali weight reduction treatment. The fibers have random surface irregularities with different cross-sectional shapes, and have a shape that cannot be achieved by conventional melt spinning of polyester. That is, FIG. 5 is an example of a cross-sectional photograph when a portion in the length direction of the fiber is randomly selected and observed, and if the selected portion is different, a cross-sectional shape having a different shape is obtained. It has been observed that identical cross-sectional shapes are not long and continuous in the fiber length direction. This is one of the major characteristics of the conjugate fiber of the present invention.Since EVAL which is present in a non-uniform distribution is immersed in high-temperature hot water or comes in contact with steam, etc., it absorbs moisture and causes swelling. Some parts are separated and some parts are twisted, and minute deformation occurs at various places. This occurs irregularly and irregularly in the fiber length direction and between the fibers. This means that natural irregularities are present in the composite fibers of the present invention, which is not possible with conventional synthetic fibers. This is presumed to be one of the reasons why the texture of the composite fiber of the present invention escapes from conventional synthetic fibers and has a texture very similar to natural fibers.

We consider the reason why the cross-sectional shape as shown in FIG. 5 appears as follows. That is, since the ethylene vinyl alcohol copolymer and the polyester are mixed in a non-uniform state, the polyester is selectively eluted and removed from the surface layer by applying an alkali weight reduction treatment to the fiber, and is not immersed in the alkali at all. Since the aggregate layer of EVAL remains on the surface of the fiber almost as it is, a complex irregular shape of the surface is likely to appear. In addition, since the mixed state of the two-component polymer retains non-uniformity both in the fiber cross-section direction and in the fiber length direction, the cross-section shape differs between filaments, and it differs in the length direction. However, it is thought that natural irregularities which have not been provided with the conventional synthetic fibers appear.

The present invention is not only effective at 100% use for long fiber woven or knitted fabrics, but also can be activated by blending with other fibers, intertwisting, interweaving, interlacing, and even when used as short fibers. Needless to say, the effect can be expected. Further, the present invention provides a pentagon, 6
It has a shape similar to a corner, and has a multi-leaf shape such as three-lobe, T-shape, four-leaf, five-leaf, six-leaf, seven-leaf, eight-leaf, etc. Regarding the shape, as long as the fiber structure described so far is expressed, the conjugate fiber of the present invention having good feeling and functional effects can be obtained.

Next, the method for producing the conjugate fiber of the present invention described above will be described in detail. In order to develop the fiber structure aimed at by the present invention, roughly speaking, polyester and EVAL are used during spinning.
It is important that the two-component polymer is formed into a fiber while maintaining the state of aggregation of the respective polymers to a certain extent, that is, the state of maintaining a heterogeneous mixed state. FIG. 6 shows a mixed spinneret device for carrying out an example of the spinning method, in which polyester and EVAL melt streams respectively extruded from separate melt extruders are weighed in predetermined amounts by separate weighing machines, The mixture is introduced from the introduction holes 2 and 3 of the introduction plate 1, mixed under predetermined conditions by the static mixer 11 provided on the mixing plates 4 and 5, passed through the intermediate plate 6, and passed through the intermediate portion 12 of the sandbox 7. After that, it is spun from the die plate 10 through the filter 8 and the current plate 9.

Here, it is very important to appropriately select the number of mixing elements of the static mixer 11. That the polymer layer of the two components in this mixing process is divided into 2 ^{3-2 15} layers is important to the present invention.

There are several types of static mixers currently in practical use, and a typical example is a Kenics static mixer having a mixing element in which 180 ° twisted blades are arranged 90 ° shifted from each other. be able to. In such a static mixer, 2 ⁿ
Since it is divided into layers, it is necessary that the number of mixing elements is in the range of ³ to ¹⁵ in order to divide into 23 to 215 layers. In the static mixer, when the number of mixing elements is 16 or more,
The mixing property between the polyester and the EVAL becomes too good, resulting in a state close to uniform mixing, and it becomes difficult to develop the desired fiber structure even if the fiber is formed and post-processed. Further, when the number of elements is 16 or more, L, which is the fiber cross-sectional area parameter between the polyester and EVAL, becomes smaller than D / 20, which is inconvenient.

Other examples include a high-mixer (Hi-Mixer) manufactured by Toray and a loss IGS mixer manufactured by Charles & Ross. These static mixer is divided into 4 ⁿ layer passes through the n-number of mixing elements, the number of mixing elements To split into 2 ^{3-2 15} layers 2-8
May be set in the range.

Division number indicating the heterogeneous mixture state in the present invention is 2 ^3-2
It is necessary that a ^15-layer, it is preferred that the number of divisions for the expression of more heterogeneous mixture state 2 ⁴ to 2 ^N layer.

Also, if the number of polymer divisions is too large from the viewpoint of production processability, polyester and EVAL will be mixed too uniformly,
During the melt mixing, a chemical reaction partially progresses between the ester bond of the polyester and the hydroxyl group of the EVAL, and a low-molecular decomposed product of the polyester and a gelled product of the three-dimensional cross-linked product of the polyester and the EVAL are rapidly generated. I realized that it would be impossible. Mixing polyester and EVAL immediately before spinning to prevent the formation of gelled matter, non-uniform mixing in a single hour and extrusion from the spinning nozzle reduces the probability of gelation reaction between the two-component polymers. This is also a very effective means. As a result, for the first time, it has become possible to stabilize the fiberization of a mixed polymer of polyester and EVAL at the operational level.

In this method, the two-component polymer mixed inhomogeneously in the static mixer is divided into thinner pieces of a mixture such as a wire mesh, a metal non-woven fabric filter, and a sand filter before reaching the nozzle through the static mixer. It is necessary to pass the member. That is, by passing through the above-mentioned divided thinning member before reaching the nozzle through the static mixer, EVAL as the A component is prevented from forming a large aggregate unit layer, and the A component and the B component are prevented. To provide fine island dispersion at the interface of
This is because the heterogeneous mixing state of the two-component polymer is stabilized, and the spinnability is improved.

The mixing ratio of the EVAL and the polyester in the static mixer should be in the range of 5:95 to 40:60 by weight. When the mixing ratio of EVAL becomes 5% by weight or less, the present invention
The feeling of natural fibers based on the polymer properties of EVAL does not sufficiently appear, which is not preferable. On the other hand, if the content is more than 40% by weight, the spinning processability and the stretching processability are unfavorably reduced, and also the physical properties of the polyester are undesirably reduced, and the strength is undesirably reduced.
On the other hand, if the polymerization degree of the EVAL used is too low, the difference in melt viscosity from the polyester during spinning becomes too large, and the balance of the heterogeneous mixed polymer becomes poor, and the spinnability decreases, which is not preferable. In addition, in terms of spinnability, the melt index of EVAL (at 190 ° C. in accordance with JIS K-6730-1977, 2160
g) under load must be 20 or less.

In addition, the alkali reduction treatment for the heterogeneous mixed conjugate fibers can be performed under the usual alkali treatment conditions performed for polyester fibers.

(Examples) Next, the present invention will be described specifically with reference to examples, but the present invention is not limited thereto.

In the following Examples and Comparative Examples, the intrinsic viscosity of the polyester was measured using an Evelote viscometer in a constant temperature bath at 30 ° C. using a mixed solvent of phenol and tetrachloroethane in equivalent amounts.

In addition, the washing recontamination test was carried out by using stearic acid, oleic acid, beef tallow, olive oil, cetyl alcohol, solid paraffin, cholesterol, carbon black, clay, silica, ferric oxide, n-decane, and portland cement as contaminants in an appropriate ratio. Mixed with a synthetic detergent and water, mixed and stirred with a homomixer to make a contaminated liquid, contaminated in the contaminated liquid using a round-dometer, then washed with running tap water, dried, and used for JIS contamination. This is determined and evaluated in a gray scale.

Example 1 An ethylene vinyl alcohol copolymer (A) having an ethylene component of 48 mol%, a saponification degree of 99% and a melt index of 14.0 g / 10 min, and a polyethylene terephthalate (B) having an intrinsic viscosity of 0.70 were separately extruded. The mixture was melt-extruded and weighed by a gear pump so that the ratio of A to B became 15: 85% by weight, and then supplied to the spinning pack. Thereafter, the product shown in FIG. Knead unevenly with an element static mixer,
Thereafter, the mixture was discharged from a round hole nozzle at a die temperature of 290 ° C. through a sand filter, and was melt-spun at a winding speed of 1000 m / min.
The obtained spun yarn is heated with a hot roller 75 ° C. and a hot plate 120 by a usual roller plate type drawing machine.
The film was stretched at 3.2 ° C. and a stretching ratio of 3.2 to obtain a 75d / 36f multifilament. The spinnability and stretchability were good and no problem.
Using the obtained multifilament as warp and weft
Weave a 1/1 plain weave. The weaving process could be performed without any problem. After processing the greige plain fabric by a usual method,
We carry out alkali weight loss treatment and get plain fabric of weight loss of approximately 20%,
Thereafter, staining was performed by a usual method.

Comparative Example 1 Using the same ethylene-vinyl alcohol copolymer (A) as in Example 1, mixed with polyethylene terephthalate (B) at a component weight ratio of 15:85 in the state of a chip and melt-extruded with one extruder. After being measured by a gear pump, the mixture was supplied to a spinning pack, discharged through a round hole nozzle through a sand filter at a die temperature of 290 ° C., and melt-spun at a winding speed of 1000 m / min. Thereafter, in the same manner as in Example 1, a 75d / 36f multifilament was obtained, a 1/1 plain fabric was similarly prepared, and an alkali weight reduction treatment was performed. For control, PET100% 75d /
A fabric having the same structure as that of the 36f filament yarn and a basis weight reduced alkali treatment was used for comparison of evaluation.

Table 1 shows the results of Example 1 and Comparative Example 1. The fiber cross section of the spun yarn obtained in Example 1 is shown in FIG. 1, and that of the spun yarn obtained in Comparative Example 1 is shown in FIG. First
As shown in the table, Comparative Example 1 was good in terms of processability, although EVAL gelled and packing became jammed, resulting in poor spinnability in about 3 hours. . On the other hand, the uneven distribution of the A and B components of the fiber cross section is The woven wave after the dyeing process shrinks well and the texture is swelled and the suppleness is good, and the sample of Comparative Example 1 and the control has softness and resilience as compared to the paper-like fabric. And high-quality cloth and came together. In terms of functionality, the recontamination evaluation with the washing contaminant was also remarkably effective as compared with the comparative example and the control sample.

When the cross section of the fiber constituting the woven fabric of Example 1 (that is, the fiber after alkali reduction) was examined with a microscope, a cross-sectional shape as shown in the photograph of FIG. 5 was observed. It was found that it had random surface irregularities of different shapes.

Examples 2 to 5 and Comparative Examples 2 and 3 In this example, the fibers were not subjected to the alkali reduction treatment. Using the same ethylene vinyl alcohol copolymer and polyethylene terephthalate as in Example 1, fiberization was carried out in the same manner as in Example 1 under the conditions shown in Table 2, and a plain fabric was prepared and dyed in the same manner as in Example 1. Processing was done. In Comparative Example 2 in which the mixing ratio of EVAL was small, the processability was good and there was no problem, but there was no characteristic in the feeling of the obtained woven fabric, and there was no characteristic in terms of functionality, and a favorable one could not be obtained. In Comparative Example 3 in which the mixing ratio of EVAL was large, the spinning property was unstable, and the single yarn breakage due to screw drop was large, and a good spun yarn could not be obtained. Therefore, the stretchability was also poor, and a woven fabric whose texture could be evaluated could not be obtained. Examples 2 and 3
The mixing ratio A / B of EVAL (A) and polyester (B) is 7/9
The tests were carried out at 3 and 30/70, but the processability was good and the fabric was good in preventing the washing and re-staining of the fabric. In Examples 4 and 5, the number of elements of the static mixer in the spinning pack was changed to 8 and 12, respectively, and the spinning was performed in the same manner as in Example 1 except that the processability was good. Was. The A / B component uneven distribution parameter D / L in the spun yarn has an effective uneven portion of 5 to 25, and a numerical value of 7 to 15 is obtained on average. Features were obtained.

Examples 6 and 7 Fiberization was performed under the same conditions as in Example 1 except that an ethylene vinyl alcohol copolymer (A) having an ethylene component of 52 mol% and a saponification degree of 9.9% and a melt index (MI value) of 6.0 was used. . However, the two points of the spinning nozzle and the mixing ratio A / B were changed, and in Example 6, the mixing ratio A / B = 1 using a T-type nozzle.
In Example 7, a dog bone type nozzle was used, and the mixing ratio A / B was set to 18/82.

FIGS. 2 and 3 are cross-sectional views of the fibers (spun raw yarns) obtained after the spinning. The processability such as spinnability, stretchability and weaving was good. When the drawn yarn was immersed in hot water, the straightened filaments generated slight distortions at various places, causing distortion with random curvature. When the woven fabric was subjected to a 25% alkali weight reduction treatment, both had a swelling, barbarian yarn-like fabric and a favorable texture.

Examples 8 and 9 Comparative Examples 4 and 5 Using an ethylene vinyl alcohol copolymer having a different ethylene component content, [η] = polyester B component was used.
Except using 0.68 PET, fiberization was carried out in the same manner as in Example 1, and then a woven fabric was prepared and dyed. However, after the pre-setting, a high-temperature and high-pressure hot water treatment was performed at 130 ° C. for 30 minutes, and after swelling processing, an alkali weight reduction of 15% was performed. Thereafter, the fabric was dyed and evaluated for texture.

Comparative Example 4 has an ethylene content of 25 mol% MI value of 0.6 Example 8 has an ethylene content of 32 mol% MI value of 1.6 Example 9 has an ethylene content of 44 mol% MI value of 6.0 Comparative Example 5 has an ethylene content of 80 mol% MI value of 40.0 Was carried out using As shown in Table 3, the result of Comparative Example 4 was poor due to poor spinnability, and the gelled product of the A polymer was clogged in the spinning filter, the pressure increased, and the gelled product was mixed into the fiber, resulting in poor drawability. No knitted fabric whose texture can be evaluated has been produced. On the other hand, in Comparative Example 5 in which the vinyl alcohol content was small in mole%, the processability was not a problem, but the texture of the obtained knitted fabric did not swell, and the form of the knitted fabric changed in the drying process, so that the product did not have a good touch. . Example 8
No. 9 had good processability, and the knitted fabric had a good feeling and touch like hemp-mixed spannit.

Comparative Examples 6 and 7 Fiberization was carried out under the same conditions as in Example 1 except that the number of the static mixer elements in the spinning pack was changed. Comparative Example 6 had 16 elements, and Comparative Example 7 had 20 elements. Both are A polymers (EVAL)
The kneadability of the polymer and the B polymer (polyester) is too good, and the reaction between the hydroxyl group of EVAL and the ester bond of the polyester occurs in the melt-mixed state of the two-component polymer, and a large amount of gelled matter is generated in the mixed polymer. It is considered that clogging of the spinning filter is likely to occur, and continuous operation of spinning cannot be performed unless the spinning pack is frequently replaced. In particular, in Comparative Example 7, in which the number of elements was 20, the single yarn breakage during spinning and the generation of fluff during stretching increased, the yield was reduced, and the processability was poor. On the other hand, the D / L, which is a parameter of uneven distribution of A and B in the spun yarn, was partially included even though it was less than 20, but was almost 20 or more, and a knitted fabric was prepared and processed in the same manner as in Example 8; It was nothing but a swelling feeling.

Examples 10 and 11 Polybutylene terephthalate having an intrinsic viscosity [η] of 0.90 was used as the polyester, and 52 mol% of the ethylene component and 99% of the saponification degree were used as the ethylene-vinyl alcohol copolymer.
In Example 10, the melt index was 14.0, and in Example 11, the melt index was 6.0, and fiberization was carried out in the same manner as in Example 1. This was carried out at a spinneret temperature of 270 ° C., and in Example 10, the mixing ratio of the polymer was A / B 15/85, and in Example 11, the spinning original yarn was collected at a winding speed of 1200 m / min at A / B 30/70. . The obtained spun yarn was drawn by a usual roller plate type drawing machine at a hot roller of 50 ° C., a hot plate of 120 ° C. and a draw ratio of 2.0 to obtain a 75d / 36f multifilament. The spinnability and stretchability were good and no problem.

Using the obtained multifilament as a warp and a weft, a 1/1 plain weave was woven. The weaving process could be performed without any problem. After the plain woven fabric is treated in the usual manner, alkali weight reduction is carried out for a longer time than in the case of polyethylene terephthalate to obtain a plain woven fabric with a weight loss of about 20%. Carried out.
The obtained woven fabric was soft and had a good feeling, and was similar to natural hemp fiber having a shiny feeling.

[Brief description of the drawings]

1, 2 and 3 are schematic views of cross-sectional photographs of the fiber of the present invention. FIG. 4 is a simulated view of a cross-sectional photograph of a comparative example fiber of uniform mixing, which illustrates the fiber diameter D of a circumscribed circle and the apparent diameter L of a B component unevenly distributed in the cross section. FIG. 5 is a photograph instead of a drawing showing the shape of the fiber, and shows the cross-sectional shape of the fiber of the present invention after alkali treatment, and shows the shape of the fiber surface made uneven by the erosion of the B component with an alkaline solution.
FIG. 6 is a cross-sectional view showing an example of a spinneret device for producing the fiber of the present invention, wherein 1 is an introduction plate, 2 and 3 are polymer introduction holes, 4 and 5 are mixing plates, 6 is an intermediate plate, and 7 is Sandboxes, 8 is a filter, 9 is a current plate, 10 is a base plate, 11 is a static mixer, and 12 is an excess part.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tomoyasu Takegami 892, Sakuhi-shi, Saijo-shi, Ehime Prefecture Kuraray Co., Ltd. JP-A-58-4820 (JP, A) JP-A-1-132830 (JP, A) JP-B-56-5846 (JP, B2) JP-B-47-40888 (JP, B1)

Claims (3)

(57) [Claims] 1. An ethylene content of 30 to 70 mol% and a saponification degree of 95.
% Or more and 190 ° C in accordance with JIS K 6730-1977
Separately, a saponified ethylene vinyl acetate copolymer (A) having a melt index of 20 or less under a load of 2160 g and a thermoplastic polyester (B) containing polyethylene terephthalate and / or polybutylene terephthalate as a main component are separately separated. melt extrusion, the weight ratio using a static mixer immediately before reaching the spinning nozzle a to: B = 5: 95~40: 60 range, the division number is 2 ^{3-2 15} become so mixed heterogeneous, Thereafter, the mixture is a fiber formed by extruding the mixture from the spinning nozzle through a dividing thinning member and forming a fiber. In the fiber cross section, the A component is distributed in an island state, and the B component region where the A component does not exist has a fiber diameter of A composite fiber that can draw a circle with a diameter of at least 1/20. 2. An ethylene content of 30 to 70 mol% and a saponification degree of 95.
% Or more and 190 ° C in accordance with JIS K 6730-1977
Separately, a saponified ethylene vinyl acetate copolymer (A) having a melt index of 20 or less under a load of 2160 g and a thermoplastic polyester (B) containing polyethylene terephthalate and / or polybutylene terephthalate as a main component are separately separated. melt extrusion, the weight ratio using a static mixer immediately before reaching the spinning nozzle a to: B = 5: 95~40: 60 range, the division number is 2 ^{3-2 15} become so mixed heterogeneous, Thereafter, the mixture is a fiber formed by extruding the mixture from the spinning nozzle through a dividing thinning member and forming a fiber. In the fiber cross section, the A component is distributed in an island state, and the B component region where the A component does not exist has a fiber diameter of A composite fiber formed by forming a random surface irregular shape with different cross-sectional shapes between single fibers by subjecting a composite fiber that can draw a circle of at least 1/20 in diameter to alkali weight reduction processing 3. An ethylene content of 30 to 70 mol% and a saponification degree of 95.
% Or more and 190 ° C in accordance with JIS K 6730-1977
Separately, a saponified ethylene vinyl acetate copolymer (A) having a melt index of 20 or less under a load of 2160 g and a thermoplastic polyester (B) containing polyethylene terephthalate and / or polybutylene terephthalate as a main component are separately separated. melt extrusion, the weight ratio using a static mixer immediately before reaching the spinning nozzle a to: B = 5: 95~40: 60 range, the division number is 2 ^{3-2 15} become so mixed heterogeneous, Thereafter, the mixture is extruded from a spinning nozzle through a division thinning member to be fiberized, thereby producing a conjugate fiber.