JP4195689B2 - Method for producing composite fiber product comprising cotton and regenerated cellulose fiber - Google Patents

Description

  The present invention relates to a method for producing a fiber product having improved dyeability (same color) without impairing flexibility with respect to a composite fiber product composed of cotton fibers and regenerated cellulose fibers.

  Composite fiber products composed of cotton fibers and regenerated cellulose fibers, for example, fabrics using blended yarns of cotton fibers and regenerated cellulose fibers, and fabrics made by interweaving or knitting cotton yarns and regenerated cellulose yarns are disadvantages of each fiber type. In recent years, various studies have been made on commercialization because of the physical properties that complement each other.

  When dyeing a composite fiber product consisting of cotton fiber and regenerated cellulose fiber, the dyeing property of cotton fiber is much lower than that of regenerated cellulose fiber, so the uniformity of dyeing between cotton fiber and regenerated cellulose fiber It was difficult to obtain (same color). This is thought to be due to the fact that the surface of the cotton fiber is called “kemp”, which has a weak strength and has a poor dyeability, resulting in a blurred state.

  Therefore, attempts have been made to improve dyeability by modifying cotton fibers with alkali metal compounds, quaternary ammonium bases, liquid ammonia, amines, or the like (Patent Document 1, Patent). Reference 2).

  Cotton fibers swell and shrink more strongly than the above treatment, and the gloss increases as the cross-sectional area increases and becomes closer to a circle. By applying tension in this state, the form is maintained even after washing with water. At that time, the crystallinity is lowered and the amorphous region is increased, so that the dyeability is improved.

As such a modification processing method for cotton fibers, “sirket processing” (mercerization processing) is the most common. This processing method involves immersing, infiltrating and infiltrating a high-concentration (18.7% to 23.5% by weight) aqueous sodium hydroxide solution under tension, such as yarn and woven fabrics, and then neutralizing and washing. There are effects such as improved dyeability, improved dimensional stability, and improved strength. Further, as a method for imparting softness, drapeability, and resilience, a processing method using liquid ammonia is also performed.
JP-A-4-202818 JP-A-9-67766

  However, if the conventional mercerizing process for improving the dyeing property of cotton fibers is applied to a composite fiber product composed of cotton fibers and regenerated cellulose fibers, the regenerated cellulose is hardened and the surface of the cotton fibers is further increased. There was a problem in that it was difficult to dye the dark color because the kemp of the product could not be removed sufficiently. Therefore, the product obtained has a low value as a product.

  In addition, liquid ammonia processing or processing using amines has a problem that dyeability is not improved.

  As a result of intensive studies in view of the above-mentioned problems, the present inventor has sufficiently removed kemps (parts having low strength and poor dyeability) existing on the surface of the cotton fiber and improves the smoothness of the fiber surface. It was noticed that it is important to quickly perform the above-mentioned in order to improve the dyeability and also to prevent the regenerated cellulose fibers from hardening. Moreover, it has been found that such processing can be easily performed using an aqueous solution of an alkali metal compound under specific conditions.

  That is, the present invention improves the uniformity of dyeing (same color) of cotton fibers and cellulose fibers in a method for producing a fiber product in which cotton fibers and regenerated cellulose fibers are mixed or combined, and has a sufficient dyeing density. The purpose is to maintain a soft texture.

According to the first aspect of the method for producing a composite fiber product composed of cotton fiber and regenerated cellulose fiber, the composite fiber product composed of cotton fiber and regenerated cellulose fiber has a surface tension at 24 ° C. of 75 dyn / cm ² or less. It is characterized by treating with an aqueous solution of an alkali metal compound that is, under no tension, until the static friction coefficient of the cotton fiber is 50 to 75% of that of the raw cotton fiber.

According to the second aspect, the composite fiber product composed of cotton fiber and regenerated cellulose fiber is subjected to static friction of the cotton fiber under tension with an aqueous solution of an alkali metal compound having a surface tension at 24 ° C. of 75 dyn / cm ² or less. Processing is performed until the coefficient is 40 to 65% of the raw cotton fiber.

  The unfinished product as used herein refers to cotton fibers in a state before being treated with the above aqueous alkali metal compound solution.

  The aqueous solution of the alkali metal compound may contain a surfactant component as the penetrating agent and other components. In addition, the above treatment is performed so as to sufficiently remove the kemp to smooth the surface of the cotton fiber and to maintain the necessary fiber strength without impairing the texture.

  According to the present invention, when dyeing or other processing is performed on a composite fiber product composed of cotton fiber and regenerated cellulose fiber, the regenerated cellulose fiber is suppressed from hardening and a soft texture can be obtained, and the following quality improvement can be realized. it can.

  First, as quality improvements related to the appearance of textile products, (1) same color improvement, (2) deep color, (3) gloss improvement, (4) wrinkle resistance improvement, (5) fineness unevenness improvement be able to. In addition, quality improvements related to the durability and other aspects of textile products can be achieved by (1) improving dimensional stability, (2) preventing fuzz, and (3) improving wrinkle resistance.

  In addition, according to the method of the present invention, it is possible to perform dyeing after uniform treatment with an alkali metal aqueous solution over the entire region of the composite fiber product, and to treat only a partial region on the fabric with an alkali metal aqueous solution. It is also possible to give a specific pattern (garbage) by dyeing after application.

  The cotton fiber that is the subject of the present invention may be of any type depending on the fiber length or production area. On the other hand, the regenerated cellulose fiber in the present invention means viscose rayon (including polynosic) by the viscose method, cupra (copper ammonia rayon) by the copper ammonia method, and “purified cellulose” (“Tencel”) by the organic solvent method. (Also referred to as Akzo Nobel Trademark) or “Lyocell”) and take the form of filaments or staples.

  The composite fiber product comprising the cotton fiber and the regenerated cellulose fiber of the present invention includes (1) a yarn obtained by blending cotton fiber and regenerated cellulose fiber, (2) a fabric woven or knitted using such a blended yarn, (3) A fabric obtained by interweaving or knitting using a yarn containing cotton yarn or cotton fiber and a yarn of regenerated cellulose fiber or a yarn containing the same is given. In addition, natural cellulose fibers such as hemp may be included, and polyurethane-based elastic fibers and synthetic fibers such as polyester and polyamide may be further included. For example, (4) a cotton fiber and a regenerated cellulose fiber, a natural fiber such as hemp or a synthetic fiber, or a semi-synthetic fiber such as cellulose acetate, or a yarn mixed with regenerated cellulose, and (5) Only these yarns, or woven fabrics, knitted fabrics, nonwoven fabrics and the like containing these yarns as constituent components may be used.

  The cotton fibers constituting these have a surface friction coefficient of 50 to 75% of the unprocessed product when treated with an aqueous solution of an alkali metal compound with no tension, and the unprocessed product when treated with tension. To 40 to 65%. By showing such a coefficient of friction change rate, as the warp on the surface of the cotton fiber becomes very small, for example, as shown in FIG. 1, white blurring is reduced, the crystallinity is further lowered, and the amorphous region is increased. Therefore, the dyeability is improved. Regardless of the fiber length of the cotton fiber and the type depending on the production area, the dyeability can be improved without impairing the texture by treating the cotton fiber so that the coefficient of static friction changes. At this time, as shown in FIG. 1, the regenerated cellulose fiber does not show a great change such as fusion due to the treatment.

The aqueous alkali metal compound solution used in the treatment of the present invention has a surface tension at 24 ° C. of 75 dyn / cm ² or less, particularly preferably 71 dyn / cm ² or less. If it is greater than 75 dyn / cm ² , the penetration of the alkali metal compound aqueous solution into the fiber product may be deteriorated, resulting in processing unevenness.

Further, in order to promote internal penetration of the treatment liquid into the fiber fabric, a surfactant added to the alkali metal compound aqueous solution to have a surface tension of 75 dyn / cm ² or less can be used. Further, a material having a surface tension at 24 ° C. of 75 dyn / cm ² or less may be used, and the temperature at the time of textile processing can be determined as appropriate.

  Examples of the alkali metal compound that can be used in the above method include sodium hydroxide, potassium hydroxide, lithium hydroxide, francium hydroxide, cesium hydroxide, and rubidium hydroxide. Among these, it is preferable to use potassium hydroxide (KOH). By mainly using potassium hydroxide, the texture of the yarn and the fabric can be suppressed from hardening.

  The concentration of the aqueous solution of the alkali metal compound used for the treatment is in the range of 10 to 50% by weight, preferably 10 to 45% by weight, more preferably 15 to 35% by weight. If the concentration is less than 10% by weight, a sufficient effect cannot be obtained. On the other hand, if the concentration is more than 50% by weight, no further effect can be expected, and the fabric texture may be cured. That is, it is particularly preferable to use a 15 to 35% by weight aqueous solution of potassium hydroxide (KOH). The treatment temperature is about 5 to 50 ° C., preferably about 10 to 30 ° C., so-called near room temperature. The treatment time is 1 second to 60 minutes, preferably 10 to 60 seconds, and can be determined as appropriate.

  Furthermore, when using together alkali metal compounds other than sodium hydroxide, and sodium hydroxide, the usage-amount of sodium hydroxide has preferable 2 weight% or less. If it exceeds 2% by weight, the texture may become hard.

  Moreover, it can process uniformly and efficiently by adding a penetrating agent to an alkali metal compound aqueous solution. As this penetrant, an anionic surfactant is preferably used. Specifically, polyethylene glycol ether sulfate ester salt, olefin sulfate sulfate salt, amide bond sulfate ester salt, ester bond sulfonate salt, ether Examples thereof include a bond sulfonate system and an amide bond ester salt system.

  A padding method, a gravure method, a rotary screen method, an ink jet method, or the like can be used to uniformly apply a treatment liquid comprising an aqueous alkali metal compound solution to the entire fabric. In addition, as a method of partially imparting on the fabric, a gravure method, a rotary screen method, an ink jet method, or the like can be used. Even methods other than these may be used as long as the processing liquid can be uniformly applied to the target region.

  In this way, a fiber product containing cotton fibers and regenerated cellulose fibers is immersed and permeated in an aqueous alkali metal compound solution at, for example, around room temperature. At this time, a state in which tension is applied may be maintained, or may be performed in a state in which tension is not applied. As a method for maintaining the tensioned state, for example, in the case of a yarn, there is a method in which a yarn is applied to two drums and a tension is applied to the yarn by widening the interval between the drums. In some cases, there is a method of applying tension in the length and width directions by using a tenter.

  In this treatment, a penetrant, a fluorescent agent, a bluing agent, etc. may be added to the treatment liquid as necessary.

  It is preferable to remove the alkali from the composite fiber product by uniformly applying an aqueous alkali metal compound solution to the composite fiber product made of cotton fiber and regenerated cellulose fiber and then washing with water or warm water for 5 seconds to 60 minutes. . Furthermore, you may add the washing process using an acidic bath as needed.

  By performing the dyeing after the treatment as described above, the dyeability of the composite fiber product can be remarkably improved as compared with the case of dyeing without treatment. If the dyeability is evaluated with a K / S value by a spectrophotometer, K / S value when not treated with an aqueous alkali metal compound solution is set to a reference value (100%), K of 150% to 300% / S value can be achieved.

  Moreover, the same color property of dyeing | staining of a cotton fiber and a regenerated cellulose fiber improves remarkably by processing with alkali metal compound aqueous solution. When dyeing is performed after the treatment with the above aqueous alkali metal compound solution under the same conditions for a fabric consisting only of cotton fibers and a fabric consisting only of regenerated cellulose, the ratio of the K / S value of the cotton fibers to the regenerated cellulose is: When it is unprocessed, the content of less than 50% improves to 60 to 90%. In addition, when the K / S value is measured by separating the cotton fiber and the regenerated cellulose fiber from the dyed blended yarn or union cloth, the same relationship is obtained.

  The treatment with the aqueous alkali metal compound solution causes the cotton fibers to swell and torsion to decrease, resulting in gloss. In the present invention, the treatment with the alkali metal compound aqueous solution removes most of the kemp and fibrils on the surface of the cotton fiber, so that the gloss is further improved.

<Example>
Evaluation items and evaluation methods in Examples and Comparative Examples are as follows.

[Surface tension of aqueous solution of alkali metal compound]
The surface tension at 24 ° C. was measured using a Junui tensiometer.

[Cotton fiber surface friction coefficient ratio]
It calculated using the following formula | equation from the friction coefficient value measured in the state of the thread | yarn using the thread | yarn friction tester according to JISL1095. The unit is%.

Coefficient of static friction of cotton fiber dyed after treatment with aqueous alkali metal compound solution
÷ Raw cotton fiber friction coefficient × 100
[Dyeability]
The surface color density of the dyed fabric was measured using a spectrophotometer (CE-3000 manufactured by Gretag Macbeth). The surface concentration ratio was set to the K / S value of Comparative Example 1 as a reference value (100%), and compared with the K / S values of other Examples and Comparative Examples. Units%.

  The K / S value is obtained by converting the reflectance measured by a spectrophotometer into an optical density value that is proportional to the staining density using the Kubelka-Munk function.

[Same color]
Cotton fiber yarn and regenerated cellulose yarn were extracted from the fabric, and the K / S value was measured for each. In addition, the same color property of the regenerated cellulose and cotton is the ratio of the K / S value of the cotton fiber part (%) when the K / S value of the regenerated cellulose part is defined as a reference value (100%). Value.

[Texture]
The sample fabric was evaluated by the JIS L 1096 A method (45 ° cantilever method). The unit is mm.

(Tear strength)
The tear strength of warp cotton was evaluated by the JIS L 1096 B method (single tongue method). The unit is N.

  A plain woven fabric composed of cotton fibers and regenerated cellulose fibers, wherein the warp yarn is cotton (30th single yarn), the weft yarn is rayon (40 dtex), and the weaving density is 69 warp / inch and 41 weft / inch. After scouring at 80 ° C. for 20 minutes using a 0.1% by weight aqueous solution of an anion / non-ion combination activator (manufactured by Nikka Chemical Co., Ltd., Sunmol BH-75) What was bleached at 90 ° C. for 60 minutes using an aqueous solution of 0.2% by weight and 0.1% by weight of sodium hydroxide was used. This plain fabric was immersed in a 20 ° C. aqueous solution containing 35% by weight of potassium hydroxide for 60 seconds without applying tension, and then washed twice with water at 80 ° C. for 10 minutes. Subsequently, neutralization was carried out with an aqueous acetic acid 0.05 wt% solution at 80 ° C. for 10 minutes to completely remove the alkali. Then, using SUMIFIX BLACK E-XF (manufactured by Sumitomo Chemical Co., Ltd.) as the dye at a concentration of 5% owf (weight% of the dye compound with respect to the fiber weight), 10% by weight of anhydrous sodium sulfate and 2% by weight of soda ash were added. Using a liquid dyeing machine, dyed at 50 ° C. and dried. The finished weaving density was 77 warps / inch and 42 wefts / inch. After dyeing, the state of the fiber surface was observed with an electron microscope.

  The evaluation results are shown in Table 1.

  A fabric similar to that used in Example 1 was prepared by applying 2% by weight of sodium hydroxide, 30% by weight of potassium hydroxide, and an anionic surfactant (Daisol S0600 manufactured by Daido Synthetic Chemical Industry Co., Ltd.) without applying tension. After immersing in a 5 wt% aqueous solution for 60 seconds, hot water was washed twice at 80 ° C for 10 minutes, and then neutralized with an acetic acid 0.05 wt% aqueous solution at 80 ° C for 10 minutes to completely remove the alkali. . Thereafter, the same dyeing as in Example 1 was used for staining. The evaluation results are shown in Table 1.

  The weave density of the finished plain woven fabric was 77 warps / inch and 42 wefts / inch, the same as in Example 1.

  Using a woven fabric similar to that used in Example 1 and applying tension under almost the same conditions as in Example 1, sodium hydroxide 2% by weight, potassium hydroxide 35% by weight, and an anionic surfactant ( Daido Synthetic Chemical Industries, Ltd. Daisol S0600) was immersed in a 3% by weight aqueous solution for 60 seconds. Subsequently, hot water was washed twice at 80 ° C. for 10 minutes, and then neutralized with a 0.05 wt% acetic acid aqueous solution at 80 ° C. for 10 minutes to completely remove the alkali. Thereafter, the same dyeing as in Example 1 was used for staining. The evaluation results are shown in Table 1.

  The weaving density of the plain fabric after finishing was 70 warps / inch and 40 wefts / inch.

  Using a woven fabric similar to that used in Example 1, after applying a tension such that the weave density of the plain woven fabric before processing is about 69 / inch and 41 weft / inch, 35 wt. %, And an anionic surfactant (Daisol S0600, manufactured by Daido Synthetic Chemical Industry Co., Ltd.) for 4 seconds. Subsequently, hot water was washed twice at 80 ° C. for 10 minutes, and then neutralized with a 0.05 wt% acetic acid aqueous solution at 80 ° C. for 10 minutes to completely remove the alkali. Thereafter, the same dyeing as in Example 1 was used for staining. The evaluation results are shown in Table 1.

  The weaving density of the plain fabric after finishing was 70 warps / inch and 40 wefts / inch.

Comparative Example 1

  The fabric used in Example 1 was dyed according to the same formulation as Example 1 without performing the alkali metal aqueous solution treatment. The evaluation results are shown in Table 1. The weave density of the plain woven fabric was 70 warps / inch and 40 wefts / inch after finishing.

Comparative Example 2

The fabric used in Example 1 was immersed in a 20 ° C. aqueous solution of 18.7% by weight of sodium hydroxide for 60 seconds without applying tension. The surface tension of the treatment aqueous solution used here was 84 dyn / cm ² as shown in Table 1. After the immersion, hot water was washed twice at 80 ° C. for 10 minutes, and then neutralized with an acetic acid 0.05 wt% aqueous solution at 80 ° C. for 10 minutes to completely remove the alkali. Thereafter, dyeing was performed in the same manner as in Example 1. The results are shown in Table 1. The weaving density after finishing was warp 82 / inch and weft 47 / inch.

Comparative Example 3

  The fabric used in Example 1 was immersed in liquid ammonia at −33 ° C. for 5 seconds without applying tension, and then ammonia was completely removed by a thermal evaporation method. Thereafter, dyeing was performed in the same manner as in Example 1. The evaluation results are shown in Table 1. The weaving density after finishing was 80 warps / inch and 45 wefts / inch.

Comparative Example 4

  A woven fabric similar to that used in Example 1 was added to an aqueous solution of 5% by weight of potassium hydroxide and 5% by weight of an anionic surfactant (Daisol S0600 manufactured by Daido Synthetic Chemical Industry Co., Ltd.) without applying tension. After immersing for 2 seconds, hot water was washed twice at 80 ° C. for 10 minutes, and then neutralized with a 0.05% by weight aqueous solution of acetic acid at 80 ° C. for 10 minutes to completely remove the alkali. Thereafter, the same dyeing as in Example 1 was used for staining. The evaluation results are shown in Table 1. The weaving density after finishing the plain weave was 72 warps / inch and 42 wefts / inch.

Comparative Example 5

The same woven fabric as used in Example 1 was used, and during treatment with an aqueous alkali metal compound solution, tension was applied to 5 % by weight of potassium hydroxide and an anionic surfactant (Daisol Synthetic Chemical Industries, Daisol S0600). ) It was immersed in a 5% by weight aqueous solution for 60 seconds. Subsequently, hot water was washed twice at 80 ° C. for 10 minutes, and then neutralized with a 0.05 wt% acetic acid aqueous solution at 80 ° C. for 10 minutes to completely remove the alkali. Thereafter, the same dyeing as in Example 1 was used for staining. The evaluation results are shown in Table 1. The weaving density of the finished plain fabric was 70 warps / inch and 40 wefts / inch.

Comparative Example 6

  A woven fabric similar to that used in Example 1 was added to an aqueous solution of 45% by weight of potassium hydroxide and 5% by weight of an anionic surfactant (Daisol S0600 manufactured by Daido Synthetic Chemical Industry Co., Ltd.) without applying tension. After soaking for a period of time, hot water was washed twice at 80 ° C. for 10 minutes, and then neutralized with a 0.05 wt% acetic acid aqueous solution at 80 ° C. for 10 minutes to completely remove the alkali. Thereafter, the same dyeing as in Example 1 was used for staining. The evaluation results are shown in Table 1. As shown in Table 1, the same color was as low as 59%. The weaving density of the finished plain woven fabric was 72 warps / inch and 42 wefts / inch.

〔Evaluation results〕
As can be seen from Table 1, the fabric dyed after the alkali metal compound aqueous solution treatment (Example 1) was more dyeable than the fabric dyed without the alkali metal compound aqueous solution treatment (Comparative Example 1). In addition, the same color property was remarkably improved. Further, compared with a fabric subjected to ordinary mercerization (Comparative Example 2), although the overall dyeing density was somewhat inferior, the same color was improved and the decrease in texture could be considerably reduced. FIG. 1 shows an electron micrograph of the processed fiber product obtained in Example 1. The processed fiber product was very smooth with few kumps. In particular, the smoothness was considerably better than that obtained when ordinary mercerizing was performed (Comparative Example 2; FIG. 5).

  In Example 2, as shown in Table 1, the same results as in Example 1 were obtained for both the dyeability and the same color. However, the texture was slightly harder than that of Example 1. This is probably because sodium hydroxide was added. FIG. 2 shows an electron micrograph of the processed fiber product obtained in Example 2. As in Example 1, the surface state was smooth with few kumps.

  In Example 3, the dyeability and the same color were substantially the same as in Example 2. Further, as shown in the photomicrograph of FIG. 3, the surface condition of the fiber was good as in the case of Example 1. However, the texture was slightly harder than that of Example 1.

  In Example 4, the dyeability and the same color were substantially the same as in Example 1. Further, as shown in the micrograph of FIG. 4, the fiber surface condition was also good as in the case of Example 1. After the treatment, the coefficient of static friction was about 46% of that of the unprocessed product. The texture was the same as in Example 1.

  In the case of Comparative Example 1 in which the alkali metal aqueous solution treatment was not performed, as shown in Table 1, the same color property was considerably low as 45%. FIG. 5 shows an electron micrograph of the obtained processed fiber product. A large amount of kemp was observed on the surface of the cotton fiber, and the surface smoothness of the cotton fiber was very low.

  In the case of Comparative Example 2 using an 18.7% by weight aqueous solution of sodium hydroxide, as shown in Table 1, the dyeability is markedly improved as compared to Comparative Example 1, but the same color and texture are the same as above. It is clearly inferior to the case of Examples 1-3. Moreover, although the electron micrograph of the obtained processed fiber product is shown in FIG. 6, a lot of kemps were recognized on the surface of the cotton fiber, and the smoothness of the fiber surface of the cotton fiber was low. On the other hand, mutual fusion was observed in the rayon fibers.

  In the case of Comparative Example 3 using liquid ammonia, as shown in the table, the decrease in the texture is small, but the dyeing property and the same color property are not significantly different from those in the case where the treatment before dyeing is not performed (Comparative Example 1). FIG. 7 shows an electron micrograph of the obtained processed fiber product. The state of the fiber surface was the same as in Example 1, with some kemps being recognized, and the smoothness was generally good. Further, as shown in Table 1, the reduction of the static friction coefficient was the same as in Example 1. However, the dyeability and the same color property shown in the middle of Table 1 are inferior to those of Comparative Example 2 in both cases.

  In the case of Comparative Example 4 using a 5% by weight potassium hydroxide aqueous solution without applying tension, as shown in Table 1, the same color property was 48%, which was considerably low. FIG. 8 shows an electron micrograph of the obtained processed fiber product. A large amount of kemp was observed on the surface of the cotton fiber, and the smoothness of the surface of the cotton fiber was very low.

  In the case of Comparative Example 5 using a 5% by weight potassium hydroxide aqueous solution while applying tension, as shown in Table 1, the same color property was 47%, which was considerably low. FIG. 9 shows an electron micrograph of the obtained processed fiber product. A large amount of kemp was observed on the surface of the cotton fiber, and the smoothness of the surface of the cotton fiber was very low.

In the case of the comparative example 6 using 45 weight% potassium hydroxide aqueous solution, the same color property and dyeing | staining property were inferior compared with the Example. Further, FIG. 10 shows an electron micrograph of the obtained processed fiber product. The surface of the cotton fiber was hardly squeezed, and the surface of the cotton fiber was slightly smooth, but the cotton strength decreased. It was big.

2 is a set of electron micrographs of the cotton-rayon interwoven fabric described in Example 1. FIG. The four photographs for each part of the fabric show the side (upper left) and cross section (lower left) of the cotton yarn, the side (upper right) and cross section (lower right) of the rayon yarn, respectively. FIG. 3 is a set of electron micrographs similar to FIG. 1 for the cotton-rayon interwoven fabric described in Example 2. FIG. FIG. 3 is a set of electron micrographs similar to FIG. 1 for the cotton-rayon interwoven fabric described in Example 3. FIG. FIG. 5 is a set of electron micrographs similar to FIG. 1 for the cotton-rayon interwoven fabric described in Example 4. FIG. 2 is a set of electron micrographs similar to FIG. 1 for the cotton-rayon union fabric described in Comparative Example 1. FIG. FIG. 3 is a set of electron micrographs similar to FIG. 1 for the cotton-rayon woven fabric described in Comparative Example 2. FIG. FIG. 4 is a set of electron micrographs similar to FIG. 1 for the cotton-rayon interwoven fabric described in Comparative Example 3. FIG. FIG. 5 is a set of electron micrographs similar to FIG. 1 for the cotton-rayon unwoven fabric described in Comparative Example 4. FIG. FIG. 6 is a set of electron micrographs similar to FIG. 1 for the cotton-rayon woven fabric described in Comparative Example 5. FIG. FIG. 7 is a set of electron micrographs similar to FIG. 1 for the cotton-rayon woven fabric described in Comparative Example 6. FIG.

Claims (4)

A composite fiber product composed of cotton fiber and regenerated cellulose fiber is treated with an aqueous solution of 10 to 50% by weight of an alkali metal compound having a surface tension at 24 ° C. of 75 dyn / cm ² or less. In addition to being able to contain 2% by weight or less of sodium hydroxide, it is characterized by substantially improving the smoothness of the surface of the cotton fiber by removing the kemp on the surface of the cotton fiber by using only potassium hydroxide. A method for producing a composite fiber product comprising cotton fiber and regenerated cellulose fiber. Cotton fiber having an unprocessed cotton fiber with a static coefficient of friction using an aqueous solution of an alkali metal compound having a surface tension at 24 ° C. of 75 dyn / cm ² or less when measured without a surfactant. 2. The treatment according to claim 1, wherein the treatment is carried out until 50 to 75% of the cotton fiber or the static friction coefficient of the cotton fiber is 40 to 65% of the raw cotton fiber under tension . A method for producing a composite fiber product comprising cotton fiber and regenerated cellulose fiber. Cotton fiber dyed after using the alkali metal compound aqueous solution having a potassium hydroxide concentration of 15 to 35% by weight to improve the smoothness of the surface of the cotton fiber by removing the kemp on the surface of the cotton fiber. The method for producing a composite fiber product comprising cotton fiber and regenerated cellulose fiber according to claim 1 or 2, wherein the K / S value of the fiber is 50 to 90% of the K / S value of the regenerated cellulose fiber. 4. The cotton fiber and the regenerated cellulose according to claim 3 , wherein the dyed product as a whole has a K / S value of 150% to 300% of that dyed without the alkali metal compound aqueous solution treatment. A method for producing a composite fiber product comprising fibers.