JPS6328123B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a mixed fiber yarn with good texture, and more particularly to a method for producing a mixed fiber yarn containing ultrafine yarns.

In recent years, for the purpose of giving woven and knitted fabrics an elegant appearance and drapability, ultra-fine yarns with a single-filament fineness of about 1 denier and ultra-fine yarns with a fineness of about 0.5 to 0.8 denier, which are even thinner than 1 denier (hereinafter referred to as ultra-fine yarns) ) has been developed and is now on the market. Woven and knitted fabrics using ultra-fine filament yarn certainly have excellent characteristics in terms of soft texture and drapability, but
On the other hand, it has the disadvantage of lacking tension in the waist.

Conventionally, in order to give stiffness and tension to woven and knitted fabrics and improve their texture, filament yarns with a thin single filament fineness and filament yarns with a thick single filament fineness are combined and drawn in the drawing process, and combined yarns are temporarily drawn in the higher processing process. The method of twisting or plying and using it as a mixed yarn has been widely adopted.

However, although such conventional methods are easy to carry out, on the other hand, it is necessary to separately manufacture thin filament yarn with a single filament fineness and filament yarn with a thick single filament fineness, which complicates the production process and increases costs. The disadvantage is that it is expensive.

Furthermore, in these conventional methods, the mixing condition of filament yarns with fine single filament fineness and filament yarns with thick single filament fineness is poor (so-called poor handling), and when woven and knitted fabrics are dyed, defects such as uneven dyeing and unevenness occur. The problem is that it is easy.

On the other hand, in order to solve the above-mentioned drawbacks, various studies have been made on methods of simultaneously spinning thin filaments and thick filaments with single filament fineness. The simultaneous spinning method has the great advantage of being a good mixture of thick and thin filaments with single filament fineness, and the production process is simple, resulting in lower costs, but it is highly difficult due to many restrictions in spinning technology. . There are two methods for simultaneous spinning: a method in which a thin filament and a thick filament with a single filament fineness are spun from the same spindle (hereinafter abbreviated as one-shot spinning), and a method in which a thin filament and a thick filament with a single filament fineness are spun from separate spindles. There is a method of winding the yarn after doubling (hereinafter abbreviated as parallel spinning), but in the case of one-shot spinning, the spinning conditions such as spinning speed, spinning temperature, and cooling air speed are all the same for thin filaments and thick filaments with single filament fineness. In the case of parallel spinning, the spinning speed is the same, and the spinning temperature is virtually the same in a normal melt spinning machine, as multiple packs are housed in the same spin block and the temperature is controlled at the same time. The spinning conditions are the same and can be changed only by the wind speed of the cooling air.

Under the above-mentioned constraints, when the mixed fiber yarn (undrawn yarn) obtained by simultaneous spinning is drawn, sagging occurs in the filament with a large single filament fineness, and when it is handled at the same time as the normal drawn yarn, it will be processed in the higher processing step. This sagging causes fuzzing and yarn breakage frequently, and even when fabricated into woven or knitted fabrics, filaments with large single filament fineness appear on the surface layer, resulting in a rough and hard texture. When drawing, sagging occurs in filaments with thick single yarn fineness because the amount of elastic recovery of filaments with thick single yarn fineness is smaller than that of filaments with thin single yarn fineness when drawing and winding. It is presumed that this is because there is a difference in the length of the filament after winding (the filament with a thicker single yarn fineness is longer). The reason why the amount of elastic recovery of a filament with a thick single yarn fineness is small is that when spinning simultaneously, as mentioned above, filaments with a thin single yarn fineness and filaments with a thick single yarn fineness are spun under the same spinning conditions. This is thought to be due to the fact that the degree of orientation of the filament becomes lower, and as a result, during drawing, the drawing stress of a filament with a thick single filament fineness is smaller than that of a filament with a thin single filament fineness.

Therefore, when co-spinning mixed fiber yarns having the same cross-sectional shape and different single filament finenesses, it is impossible to make the drawing stress of the thin filament and the thick filament the same. Figure 1a shows an example in which the present inventors actually measured the drawing stress when the spinning conditions (spinning speed, spinning temperature, cooling air speed) were kept constant and the single yarn fineness was varied using a normal round cross-section yarn. show. As is clear from this figure, the change in drawing stress is relatively small in the region where the single fiber fineness is greater than 1.5 denier, but the change in drawing stress is relatively small in the region where the single fiber fineness is less than 1.5 denier, especially 1.0 denier or less. The ratio increases rapidly, and the smaller the single fiber fineness, the greater the absolute value of the drawing stress. From the results shown in this figure, it can be seen that simultaneous spinning of mixed yarns combining single yarn finenesses of 1.5 denier or more can be achieved relatively easily. In fact, simultaneous spinning of mixed fiber yarns consisting of a combination of single yarn finenesses of about 2 to 8 deniers has been put to practical use. However, 2.
When filaments of ~3 deniers or more are co-spun, the difference in stretching stress increases and it becomes difficult to avoid sagging. For this reason, there is no known technique for co-spinning mixed fiber yarns containing ultrafine filaments with a single filament fineness of 1 denier or less by ordinary melt spinning.

The inventors of the present invention have made intensive studies to solve the various problems described above, and have found that when comparing the drawing stress of a hollow filament and a round-section filament spun under the same spinning conditions at the same denier, the drawing stress of the hollow filament is lower than that of a round-section filament. The present invention was developed based on the discovery that it is much larger.

That is, an object of the present invention is to obtain a mixed fiber yarn by simultaneously melt-spinning an ultrafine filament group (A) and a hollow filament group (B), and to improve the fineness ( d ₁ ) and the fineness (d ₂ ) of the hollow filament single yarn constituting the hollow filament group (B) are as follows, (), (), ()
This is achieved by melt spinning under conditions that simultaneously satisfy the following formulas.

0.4≦d _{1 ≦} 1.2 (denier) () 1.5≦d ₂ ≦4.0 (denier) () 2≦d ₂ /d ₁ ≦4.5 () However, the fineness of single yarn in formulas (), (), and () is This is the fineness of the single yarn after drawing.

Next, the configuration and effects of the present invention will be explained in detail. The single fiber fineness of the ultrafine filament group (A), which is one of the components constituting the mixed fiber yarn, must satisfy the formula (). If the single yarn fineness is less than 0.4 denier, it will be extremely difficult to simultaneously spin with the hollow filament group using the normal spinning method, and even if simultaneous spinning is possible, the drawing stress of the ultrafine yarn will become excessive and the resulting mixed fiber yarn will have problems. Sagging of the hollow filament occurs.

In addition, mixed fiber yarns that are a combination of ultrafine yarns of less than 0.4 denier and single yarn fineness of 1.5 to 4.0 deniers are not preferred because the difference in dyeing between the ultrafine yarns and the hollow fibers increases, which increases dyeing defects such as irritation. .

On the other hand, if the single yarn fineness of the ultra-fine yarn exceeds 1.2 denier, when it is made into a mixed fiber yarn, the elegant appearance, soft texture, and drapability characteristic of the ultra-fine yarn will be lost. The fineness of each single yarn constituting the ultra-fine filament group may be the same or different as long as it is within the range of formula ().

The single fiber fineness of the hollow filament group, which is the other component constituting the mixed fiber yarn, must satisfy the formula (). If the single yarn fineness of the hollow filament is less than 1.5 denier, it will be difficult to provide sufficient stiffness and tension to the woven or knitted fabric, and if it exceeds 4.0 denier, the texture will become rough and hard, which is undesirable.

The ratio of the single fiber fineness of the ultra-fine filament and the hollow filament must satisfy the formula ().

When d ₂ /d ₁ is less than 2, no sagging occurs, but the difference in single fiber fineness between the ultrafine filament and the hollow filament becomes too small, making it impossible to obtain a sufficient fiber mixing effect.

On the other hand, when d ₂ /d ₁ exceeds 4.5, sagging becomes large, which poses a practical problem, and the difference in dyeing between the ultrafine fiber and the hollow fiber increases, making uneven dyeing, irritation, etc. more likely to occur. Next, the reason why sagging can be prevented by using a hollow filament will be explained.

Figure 1 compares the stretching stress when undrawn round cross-sections, triangular cross-sections, and hollow cross-sections obtained by spinning polyethylene terephthalate under the same conditions except for changing the single fiber fineness are stretched at the same stretching ratio. This is what is shown. As is clear from this figure, the drawing stress of the hollow filament yarn is much greater than that of the round cross-section yarn or the triangular cross-section yarn of the same fineness.

For example, when drawing a 0.7-denier round-section filament and a 2-denier round-section filament at the same time, the difference in drawing stress between the two is as much as 0.4g/d, causing sagging. In the case of a hollow filament, the stretching stress difference is reduced to 0.1 g/d and no sagging occurs. The limit of the stretching stress difference at which the occurrence of sagging does not become a practical problem is 0.25 g/d or less, and the most preferable range is 0.15 g/d or less.

The degree of hollowness of the hollow filament is preferably 5% to 35%.

If the degree of hollowness of the hollow filament is less than 5%, there will be no sufficient hollow effect, while if it exceeds 35%, it will be difficult to stably spin the filament, and the effect will not increase even if the degree of hollowness is further increased.

Another reason for using hollow filaments for thick yarns is that compared to using round-section filaments, hollow filaments can reduce the difference in dyeing of mixed fiber yarns, and avoid dyeing defects such as uneven dyeing and unevenness. The key point is that it can be vastly improved.

FIG. 2 shows the results of measuring the lightness (L value) of dyed fabrics when round-section filament yarns and hollow-section filament yarns were knitted into tubes and dyed under the same dyeing conditions. This figure shows that for both round-section filaments and hollow filaments, the lightness (L value) tends to increase as the single filament fineness becomes finer, and when comparing the lightness (L value) of hollow filaments at the same fineness, the lightness (L value) of round-section filaments ( It can be seen that it is higher than the L value).

In other words, if a hollow fiber is used as a thick filament in combination with an ultra-fine filament, the difference in brightness between the ultra-fine filament and the thick filament will be much smaller than when a normal round-section yarn is used, and uneven dyeing and irritation will occur. This shows that such drawbacks can be avoided.

Incidentally, the difference in lightness that allows defects such as uneven dyeing and irritation when dyed is L value 2.5 or less, particularly preferably 1.5 or less.

It is preferable that the ratio of the fineness of the ultrafine filament group and the hollow filament group to the fineness of the mixed yarn satisfies the following expressions () and (), respectively.

0.4≦Fineness of ultrafine filament group (A)/Fineness of mixed yarn≦0.
85 () 0.15≦Fineness of hollow filament group (B)/Fineness of mixed yarn≦0
.60 () If the ratio of ultra-fine filaments is less than 0.4 and the ratio of hollow filaments exceeds 0.6, it becomes difficult to give the woven or knitted fabric an elegant appearance or soft texture; is 0.85
If the ratio of the hollow filament group exceeds 0.15, a soft texture can be obtained, but there is a risk that the elasticity and tension will be insufficient.

The mixed fiber yarn of the present invention can be obtained by co-spinning a group of ultrafine filaments and a group of hollow filaments as described above, and then drawing the yarn. For simultaneous spinning, a method can be adopted in which a group of hollow filaments and a group of ultra-fine filaments are simultaneously spun from the same spinneret, or a method in which a group of hollow filaments and a group of ultra-fine filaments are discharged from separate adjacent spinnerets, combined, and wound. The former method is the most preferable from the viewpoints of cost, productivity, and flexibility of the mixed yarn.

In addition, since the mixed fiber yarn obtained by the method of the present invention contains ultra-fine filaments, fuzz and yarn breakage are likely to occur during high-order processing steps. To prevent these defects, interlacing treatment (interlacing treatment) with fluid is performed during the production process. treatment) is preferred. Although the interlacing process can be employed in both the spinning process and the stretching process, it is more efficient to carry out the process between the stretching roller and the winding process in the stretching process. The degree of confounding is determined by U.S. Patent No.
The degree of entanglement (Coherency Factor) measured by the hook drop method according to the specification of No. 2985995 is preferably 5 to 70, particularly preferably 10 to 50. When the CF value is less than 5, the confounding effect is insufficient, and when it exceeds 70, irritation due to confounding may occur.

The present invention relates to polyethylene terephthalate, polytetramethylene terephthalate, polyethylene-
2,6-naphthalene dicarboxylate, poly-
It can be applied to polyesters such as p-ethyleneoxybenzoate and copolymerized polyesters, but polyethylene terephthalate is particularly preferred because it easily imparts a good texture as a textile fiber and can be industrially produced at relatively low cost.

Here, polyethylene terephthalate means a polymer in which 85 mol% or more of its constituent units are essentially polyethylene terephthalate units. This polyethylene terephthalate may be copolymerized with polyalkylene glycol or sulfonic acid metal salt for the purpose of improving dyeability, or may be added with appropriate light stabilizers, heat stabilizers, matting agents, plasticizers, pigments, surface modifying materials, etc. It may also contain fine powder, flame retardants, etc.

The present invention will be explained below with reference to Examples.

Example 1 A polyethylene terephthalate chip with an intrinsic viscosity of 0.63 g/d measured in an orthochlorophenol solvent at 25°C was drilled with 12 hollow holes consisting of three arcuate slits and 72 round holes with a hole diameter of 0.18 mm. Using a spindle made of
Melt spinning was performed at a spinning speed of 1,350 m/min to obtain an undrawn product of 227 denier.

Next, the undrawn yarn was stretched at a stretching ratio of 3.1 times, at a stretching temperature (heating roller temperature) of 88°C, and at a heat treatment temperature (heating plate temperature).
It was stretched at 140°C and at a stretching speed of 500 m/min, and then air entangled using an entangling device similar to the fluid entangling device disclosed in U.S. Patent No. 2,985,995, and then wound to form a 75 denier 84 filament. A drawn yarn was obtained. The drawn yarn is a mixed yarn composed of 12 hollow filaments of 2.0 denier and 72 ultrafine filaments of 0.7 denier, and has a strength of 5.1
It has good yarn quality with g/d, elongation of 33%, boiling water shrinkage rate of 7.1%, Worcester unevenness of 0.6%, and entanglement degree of 36, and there is no sagging on the surface of the drawn pattern as well as on the unwound yarn. had not occurred.

Example 2 The mixed yarn of 75 denier 84 filament obtained in Example 1 was twisted at 500 times/m for the warp yarn, and the yarn twisted at 2500 times/m was used for the weft yarn. and weaved palace crepe. No sagging occurred in the mixed fiber yarn during the weaving preparation process and the weaving process, and process passability was good.

Next, the obtained fabric was subjected to a 20% weight reduction treatment (alkali treatment), and then Sumikaron Blue S-BG
(manufactured by Sumitomo Chemical) under conditions of 3% owf. The obtained cloth hanger had no uneven dyeing or irritation, had an elegant texture and drapability, and had excellent elasticity and tension.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the relationship between the single fiber fineness of fibers with different cross sections and drawing stress, and Figure 2 is an explanatory diagram showing the relationship between the single fiber fineness of round cross-section and hollow cross-section yarns and the L value of dyed fabric. .

Claims (1)

[Claims] 1. Ultrafine filament group (A) and hollow filament group
(B) is simultaneously melt-spun to obtain a mixed fiber yarn, the fineness (d ₁ ) of the ultrafine filament single fibers constituting the ultrafine filament group (A) and the hollow filament single yarn constituting the hollow filament group (B) are determined. A method for producing a mixed fiber yarn, characterized in that the fineness (d ₂ ) satisfies the following formulas (), (), and () at the same time. 0.4≦d ₁ ≦1.2 (denier) () 1.5≦d ₂ ≦4.0 (denier) () 2≦d ₂ /d ₁ ≦4.5 () 2 Ultrafine filament group (A) and hollow filament group
2. The method for producing a mixed fiber yarn according to claim 1, wherein (B) is spun from the same spinneret. 3 Ultra-fine filament group (A) and hollow filament group
2. The method for producing a mixed fiber yarn according to claim 1, wherein the yarns (B) are discharged from respective adjacent individual nozzles, and then the yarns are combined and wound. 4. The method for producing a mixed fiber yarn according to claim 1, characterized in that a polyester polymer in which 85 mol% or more of the structural units is ethylene terephthalate is used.