JP2007231475A - Undrawn conjugated fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a undrawn conjugated fiber having a characteristic of "opacity" in wet state and imparting improved windbreaking and heat retaining property to a cloth by decrease of gap, and stably expressing the characteristic even after being subjected to a dyeing, finishing process, or the like, and imparts a soft feeling. <P>SOLUTION: The undrawn conjugated fiber has a cross sectional shape in which a polyester component and a polyamide component are bonded, and the conjugated fiber has a crimping percentage DC of 1.5-6.0% and has a crimping percentage HC after being soaked in water of 2.0-12.0%, and has a difference ΔC in crimping percentage of 1.5-8.0%, which is represented by the following formula, and the fiber has a rupture elongation of 40-140% and a stress at 60% extension of 0.55-1.30 cN/dtex, after being subjected to the treatments of a boiling water treatment for 30 min, dry heat treatment at 100°C for 30 min to crimp the fiber and then heat treatment of the fiber at 160°C for 1 min. Formula: ΔC(%)=HC(%)-DC(%). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a composite unstretched fiber whose crimping rate reversibly changes greatly depending on humidity. More specifically, a composite unstretched fabric that exhibits excellent crimp rate change characteristics even after dyeing and finishing processes, the wet voids are lower than those during drying, and at the same time a fabric having a very soft texture is obtained. Regarding fiber.

  It has been well known that natural fibers such as cotton, wool and feathers reversibly change in form and crimp rate due to changes in humidity. Studies have been conducted for a long time to provide a function for synthetic fibers, and proposals for side-by-side type composite fibers of nylon 6 and modified polyethylene terephthalate have already been made in Patent Documents 1 and 2, etc. These known composite fibers have not been put to practical use because the reversible crimp rate change due to humidity change is small.

  Thereafter, Patent Documents 3 and 4 and the like with improved heat treatment conditions have been proposed. Furthermore, the thing which applied the said prior art, such as patent documents 5-8 is proposed. However, in the above-described conventional technology, the change in the crimp rate becomes small after passing through processes such as dyeing and finishing, and the actual situation is that the practical level has not been reached.

  On the other hand, in Patent Document 9, an attempt is made to improve the above-mentioned problem by using a polyamide component and a polyamide component having a high moisture absorption rate, such as nylon 4, in which the polyester component and the polyamide component are joined in a flat shape. However, nylon 4 has poor yarn-making stability, the crimping performance is lowered after heat treatment, and there is a limit in practical use even for such a composite fiber.

  On the other hand, in addition to ensuring the stable quality in the above-described yarn-making property and finishing, “translucency” has become a problem in recent years due to diversification of required characteristics. In other words, when a normal woven or knitted fabric made of synthetic fiber or natural fiber is used for swimming wear, sports wear, etc., the fabric becomes wet due to water or rain, so that it becomes easy to see through, and windproof and heat retaining properties are also reduced. Such a problem has arisen. Furthermore, with the diversification of required characteristics, there is a demand for materials that have a soft texture as well as simple functionality.

Japanese Examined Patent Publication No. 45-28728 Japanese Patent Publication No.46-847 JP 58-46118 A JP 58-46119 A Japanese Patent Laid-Open No. 61-19816 JP 2003-82543 A JP 2003-41444 A JP 2003-41462 A JP-A-3-213518

  The present invention has been made against the background of the above-described conventional technology, and its purpose is to have a property of “not transparent” even when wet with water, and further, the voids of the fabric are reduced at that time, thereby preventing wind and heat retention. It is an object of the present invention to provide a composite unstretched fiber that can stably produce these excellent characteristics even after passing through processes such as dyeing and finishing, and can obtain a soft texture.

According to the study by the present inventors, the above object is a composite unstretched fiber having a fiber cross-sectional shape in which a polyester component and a polyamide component are joined, and the fiber is treated with boiling water for 30 minutes, and further 100 ° C. And 30 minutes of dry heat treatment to develop crimp, and the fiber crimped DC for 1 minute at 160 ° C. has a crimp ratio DC of 1.5 to 6.0%, and the fiber is crimped after being immersed in water. The rate HC is 2.0 to 12.0%, the difference ΔC between these crimping rates represented by the following formula is 1.5 to 8.0%, the elongation at break is 40 to 140%, It has been found that this can be achieved with a composite unstretched fiber characterized by a stress at 60% elongation of 0.55 to 1.30 cN / dtex.
ΔC (%) = HC (%) − DC (%)

  According to the present invention, even when wet, it has a property of “not transparent”, and as a result, has excellent properties of waterproofness and heat retention. It is possible to provide a composite unstretched fiber that is improved, has a very soft texture, and that stably exhibits these characteristics even after undergoing steps such as dyeing and finishing. For this reason, the composite unstretched fiber is extremely excellent in practicality, and at the same time, achieves high comfort and texture that are unprecedented as a final product such as clothing.

  Examples of the polyester component constituting the composite unstretched fiber of the present invention include polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate and the like. Among these, polyethylene terephthalate is more preferable from the viewpoint of cost and versatility.

  In the present invention, the polyester component is preferably a modified polyester in which 5-sulfoisophthalic acid is copolymerized. At that time, if the copolymerization amount of 5-sodium sulfoisophthalic acid is too large, peeling is less likely to occur at the bonding interface between the polyamide component and the polyester component, but excellent crimping performance cannot be obtained. Although the amount of copolymerization is too small and excellent crimp characteristics are obtained, it is not preferable because peeling tends to occur at the bonding interface between the polyamide component and the polyester component. For this reason, the copolymerization amount of 5-sodium sulfoisophthalic acid is preferably 2.0 to 4.5 mol%, and more preferably 2.3 to 3.5 mol%.

  On the other hand, if the intrinsic viscosity of the polyester component is too low, the yarn-forming property is lowered and fluff is easily generated, which is not preferable in terms of industrial production and quality. On the other hand, even if the intrinsic viscosity is too high, the spinnability and stretchability on the polyester component side are lowered by the thickening action by copolymerization of 5-sodium sulfoisophthalic acid, and fluff and yarn breakage are likely to occur. Become. Accordingly, the intrinsic viscosity of the polyester component is preferably 0.30 to 0.43, and more preferably 0.35 to 0.41.

On the other hand, the polyamide component is not particularly limited as long as it has an amide bond in the main chain, and examples thereof include nylon 4, nylon 6, nylon 66, nylon 46, nylon 12, and the like. Nylon 6 and nylon 66 are particularly preferable from the viewpoints of stability and versatility. The polyamide component may be copolymerized with other components based on these.
Further, both components described above may contain pigments such as titanium oxide and carbon black, known antioxidants, antistatic agents, light-proofing agents, and the like.

  The composite unstretched fiber of the present invention is a composite fiber having a fiber cross-sectional shape in which the polyester component, the polyester component, and the polyamide component are joined. As a composite form of the polyamide component and the polyester component, a form in which both components are joined in a side-by-side manner is preferable from the viewpoint of crimp development. The cross-sectional shape of the composite unstretched fiber may be a circular cross section or a non-circular cross section. For the non-circular cross section, for example, a triangular cross section or a square cross section can be adopted. In addition, a hollow part may exist in the cross section of the said composite fiber.

  The ratio of the polyester component to the polyamide component in the fiber cross section is preferably 30/70 to 70/30, more preferably 60/40 to 40/60, based on the area.

  In the present invention, the composite unstretched fiber is treated with boiling water for 30 minutes, further subjected to a dry heat treatment at 100 ° C. for 30 minutes to develop crimps, and a fiber subjected to a dry heat treatment at 160 ° C. for 1 minute is described below. The requirements regarding the crimp rate DC, the crimp rate HC after immersion in water, and the difference ΔC between these crimp rates are satisfied at the same time, and the composite unstretched fiber satisfies the elongation and 60% stress described later. It is important to do. As a result of the study by the present inventors, the composite fiber having such crimp characteristics has an increased crimp rate due to moisture absorption, and the fabric does not become “translucent” even when wetted with water. It has been found that the air gap and the heat retention are improved due to clogging, and the properties are stably exhibited even after dyeing and finishing processes. In addition, the composite unstretched fiber having a specific elongation and 60% stress, which will be described later, greatly increases the crimp rate change and further enhances the above-mentioned see-through prevention effect and windproof / heat retention improvement effect, and It was found that there was no variation in shrinkage and that it was excellent in terms of quality.

  That is, the crimp rate DC needs to be 1.5 to 6.0%, preferably 2.0 to 5.5%, more preferably 2.3 to 5.4%. If the crimp ratio DC is less than 1.5%, the texture when used as a fabric tends to deteriorate. On the other hand, when the crimp ratio DC exceeds 6.0%, the crimp ratio DC tends to be larger than the crimp ratio HC after water immersion, and it is difficult to see through, and the gap of the fabric is reduced, thereby preventing wind and heat retention. This is not preferable because it tends to be difficult to obtain a fabric with improved resistance.

  The crimp ratio HC after immersion in water is preferably 2.0 to 12.0%, more preferably 2.5 to 10.0%. When the crimping ratio HC is less than 2.0%, the crimping ratio after immersion in water is too low, and the desired effect of preventing see-through and the effect of improving windproof and heat retaining properties are insufficient. On the other hand, if the value of the crimp ratio HC exceeds 12.0%, it is not preferable because the fabric shrinks greatly when it contains water, and it is not practical and the texture is lowered.

  The difference ΔC between the HC and DC is 1.5 to 8.0%, preferably 1.8 to 7.5%, more preferably 2.0 to 7.0%. When the value of ΔC is less than 1.5%, there is a small effect of improving the crimp rate after immersion in water, and it is difficult to see through when wet with water, and the fabric has reduced voids and improved windproof and heat retaining properties. It is not preferable because it cannot be obtained. On the other hand, when ΔC exceeds 8.0%, it is not practical because the fabric shrinks greatly when water is contained, and the texture is also lowered.

  In the present invention, it is important that the composite fiber is a composite unstretched fiber having a breaking elongation of 40% to 140% and a 60% stress of 0.55 to 1.30 cN / dtex. The change in crimp rate due to can be increased, and an extremely soft texture can be obtained when the fabric is used. At the same time, there is an effect of reducing the variation in crimps and preventing stained spots.

  That is, when the elongation at break is less than 40% or the stress at 60% exceeds 1.30 cN / dtex, a soft texture is not obtained when the fabric is used, and ΔC tends to be less than 1.5, thereby preventing see-through. There is a tendency that it is difficult to obtain the effect and the effect of improving windproof and heat insulation. On the other hand, when the 60% stress is less than 0.55 cN / dtex or the elongation at break exceeds 140%, the variation in crimp becomes large and the quality deteriorates, and ΔC becomes larger than 8.0% and becomes wet with water. Tend to shrink and the texture tends to decrease. In addition, dyeing spots tend to occur, and the handleability tends to decrease, which is not preferable.

  The form of the composite unstretched fiber of the present invention basically needs to be a form in which the polyester component is disposed inside the crimped form and the polyamide component is disposed outside the crimped form. This is because, in this form, the inclusion of water causes the polyamide component to stretch and crimps to increase. In that sense, it is preferable that neither the polyester component nor the polyamide component increase the crystallinity.

  The total fineness of the composite unstretched fiber of the present invention can be 40 to 200 dtex, and the single yarn fineness is 1 to 6 dtex. In addition, you may perform a confounding process as needed.

  In order to produce the composite unstretched fiber of the present invention, for example, as described in JP-A No. 2000-144518, the high-viscosity component side and the low-viscosity side discharge holes are separated and the high-viscosity side discharge line is separated. By using a spinneret with a reduced speed (with a larger discharge cross-sectional area), the molten polyester is passed through the high viscosity side discharge holes and the molten polyamide is passed through the low viscosity side discharge holes to be joined and cooled and solidified. Obtainable.

  In that case, it is necessary to wind up at high speed, without providing extending | stretching heat processing. A winding speed of 2500 to 5000 m / min gives preferable results. When the winding speed is less than 2500 m / min, the resulting composite fiber has an excessively high elongation at break, which is not preferable. On the other hand, when the winding speed exceeds 5000 m / min, yarn breakage frequently occurs during yarn production, which is not preferable.

  In order to develop crimp in the composite undrawn fiber of the present invention, this is first treated with boiling water. Thereby, the crimp by which the polyester component is arrange | positioned inside is obtained. However, in this state, since moisture is contained, the polyamide grows due to the plasticizing effect of water, so the crimp itself changes over time and becomes unstable. Except for stabilizing crimp. As a standard for stabilizing the crimp characteristics, the crimp characteristics are as follows. The composite fiber as described above is treated with boiling water for 30 minutes, and further subjected to dry heat treatment at 100 ° C. for 30 minutes to develop crimps. The composite fiber evaluated by such a method must be subjected to a dry heat treatment for a minute, and a fabric having the desired performance can be obtained even if heat treatment is performed in a finishing step that is usually performed.

  The composite undrawn fiber of the present invention can be used alone, and can also be used as a mixed fiber mixed with other fibers. Moreover, it can be used as a false twisted yarn by further false twisting if necessary, and can also be used as a composite false twist having different elongations.

The composite unstretched fiber of the present invention can be used for various applications for clothing. For example, it is particularly preferably used in applications requiring comfort such as swimwear, various sportswear, inner materials, uniforms, and the like. it can.
Needless to say, the present composite fiber and natural fiber can be further combined and further effective, and a combination of urethane or polytrimethylene terephthalate may be used for further stretching.

Hereinafter, the present invention will be described more specifically with reference to examples. In addition, each item in an Example was measured with the following method.
(1) Intrinsic viscosity of polyamide and polyester Polyamide was measured at 30 ° C. using m-cresol as a solvent. The polyester was measured at 35 ° C. using orthochlorophenol as a solvent.

(2) Good yarn-making property: Spinning is carried out continuously for 10 hours, and the yarn-making property is good with 0 to 1 yarn breakage.
Slightly poor: Spinning is carried out continuously for 10 hours, and the yarn breakage is slightly worse, 2 to 4 times.
Defective: Spinning is performed continuously for 10 hours, and yarn breakage is 5 or more times.

(3) Interfacial Peeling between Polyamide Component and Polyester Component An arbitrary cross section of the composite unstretched fiber was photographed 1070 times in color, and the situation of interfacial peeling between the polyamide component and the polyester component in the filament was investigated.
None: There was almost no peeling (0 to 1) at the interface.
Slightly present: Peeling at the interface was present in 2 to 10 filaments.
Existence: Peeling at the interface was present in almost all filaments.

(4) Elongation at break (%)
After leaving the fiber sample in a room maintained at a constant temperature and humidity of 25 ° C. and 60% humidity for a whole day and night, the sample length of 100 mm was set on a tensile tester Tensilon manufactured by Shimadzu Corporation, and the speed was 200 mm / min. The strength and elongation at break were measured.

(5) 60% elongation stress (cN / dtex)
From the stress-elongation curve obtained by measuring the above strength and elongation, the stress at 60% elongation was obtained, and the value was obtained by dividing the value by the fineness of the composite fiber.

(6) Crimp rate DC, crimp rate HC after water immersion, and their difference ΔC
A 2700 dtex case was made from the composite fiber and treated in boiling water for 30 minutes under a light load of 6 g (2.2 mg / dtex). The moisture was removed by lightly removing with a filter paper, followed by drying at 100 ° C. for 30 minutes under a load of 6 g (2.2 mg / dtex). Furthermore, this casserole was heat-treated at 160 ° C. for 1 minute under a load of 6 g (2.2 mg / dtex) to obtain a measurement sample.
(A) Crimp rate DC (%)
The measurement material (cassette) subjected to the above treatment was treated under a load of 6 g (2.2 mg / dtex) for 5 minutes, and then this skein was taken out and further 600 g (total 606 g: 2.2 mg / dtex + 220 mg / dtex). ) And left for 1 minute to determine the length L0 of the case. Next, the load of 600 g was removed, and the load was left for 1 minute under a load of 6 g (2.2 mg / dtex), and the length L1 was determined. The crimp rate DC was determined from the following calculation formula.
DC (%) = L0−L1 / L0 × 100
(B) Crimp rate HC (%) after water immersion
Using the same case after obtaining the crimp rate DC, it was treated in water (room temperature) for 10 hours under a load of 6 g (2.2 mg / dtex). The casserole was wiped off with a filter paper, and a load of 600 g (total 606 g: 2.2 mg / dtex + 220 mg / dtex) was further applied and left for 1 minute to determine the length L2 of the casserole. Next, the load of 600 g was removed, and the product was left for 1 minute under a load of 6 g (2.2 mg / dtex), and the length L3 was determined. The crimp rate DC after water immersion was calculated | required from the following formula.
HC (%) = L2-L3 / L2 × 100
(C) ΔC (%)
The difference ΔC between the above-described crimp rate DC and the crimp rate HC after water immersion was determined by the following equation.
ΔC (%) = HC (%) − DC (%)
(D) Variation in crimp HC (%) was measured three times, and the determination was made as follows based on the variation in measured values.
Good: Variation is less than 0.5% Defect: Variation is 0.5% or more

(7) Characteristics of cylinder knitting Composite unstretched fiber was knitted, and was dyed with boil with a cationic dye. Water is dropped onto this tubular knitting, and the situation of the water dripping part and its surroundings is investigated with a side photograph (magnification 200) of the tubular knitting. Was judged.
(A) Stitch change (degree of reduction of voids)
Good: The stitches are remarkably shrunk by water dripping (voids are reduced).
Slightly poor: Almost no change in stitches due to water dripping (almost no change in voids).
Defect: The stitches are rather elongated due to water dripping (the voids are enlarged).
(B) Good prevention of see-through: The sense of see-through is reduced by dripping water.
Slightly poor: No change in the sense of transparency due to dripping water
Defect: The feeling of see-through is increased by dripping water.

(8) Texture The composite unstretched fiber was knitted, boiled with a cationic dye, washed with water, set in a dry heat at 160 ° C. for 1 minute, used as a measurement sample, and its feel was evaluated.
Good: The texture is soft.
Poor: The texture is rough.

[Example 1]
Nylon 6 having an intrinsic viscosity [η] of 1.3 and modified polyethylene terephthalate copolymerized with 3.0 mol% of 5-sodium sulfoisophthalic acid having an intrinsic viscosity [η] of 0.39 are each 270 ° C. It melts at 290 ° C., and uses a composite spinneret described in JP 2000-144518 A to form extruded side-by-side type composite yarns at a discharge rate of 19.4.7 g / min. Then, the yarn was wound at a speed of 3500 m / min to obtain a composite unstretched fiber of 110 dtex24 fil. The yarn-making property was extremely good, and the yarn was continuously spun for 10 hours and there was no yarn breakage. The results are shown in Table 1.

[Examples 2-6, Comparative Examples 1-2]
A composite undrawn fiber was obtained in the same manner as in Example 1 except that the discharge amount of each component in spinning (the same amount for both the polyester component and the polyamide component) was changed as shown in Table 1. The results are shown in Table 1.

[Examples 7 to 9, Comparative Example 3]
A composite unstretched fiber was obtained in the same manner as in Example 1 except that the amount of copolymerization of the modified polyester component 5-sulfoisofluric acid was changed as shown in Table 1. The results are shown in Table 1.

[Examples 10 to 11 and Comparative Examples 4 to 5]
A composite undrawn fiber was obtained in the same manner as in Example 1 except that the intrinsic viscosity [η] of the modified polyester component was changed as shown in Table 1. The results are shown in Table 1.

  According to the present invention, it is possible to provide a composite unstretched fiber in which the crimp rate reversibly changes depending on humidity, and has a property of “not transparent” even when wet, and the fabric is clogged by moisture absorption. It is possible to provide a composite unstretched fiber that exhibits an excellent function such that wind resistance and heat retention are improved by reducing the voids. Further, the composite unstretched fiber exhibits a stable crimp rate change characteristic even after the dyeing / finishing process, and is therefore extremely excellent in practicality. In addition, when used as a fabric, a very soft texture is obtained and there is little variation in crimping, so that not only has excellent comfort as a final product such as clothing, but also has high quality. And its industrial value is extremely high.

Claims (2)

A composite unstretched fiber having a cross-sectional shape of a fiber in which a polyester component and a polyamide component are bonded. The fiber is treated with boiling water for 30 minutes and further subjected to a dry heat treatment at 100 ° C. for 30 minutes to develop crimps. The crimp rate DC of the fiber subjected to dry heat treatment at 160 ° C. for 1 minute is 1.5 to 6.0%, and the crimp rate HC after water immersion is 2.0 to 12.0%, The difference ΔC between these crimping rates represented by the following formula is 1.5 to 8.0%, the elongation at break is 40 to 140%, and the stress at 60% elongation is 0.55 to 1.30 cN / A composite undrawn fiber characterized by being dtex.
ΔC (%) = HC (%) − DC (%)   The polyester component is a modified polyester having an intrinsic viscosity (IV) of 0.30 to 0.43 and 2.0 to 4.5 mol% of 5-sodium sulfoisophthalic acid copolymerized based on the acid component. The composite unstretched fiber according to claim 1.