JPH09209263A - Fiber structure and production of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fiber structure excellent in moisture absorbing property and also a soft touch feeling by performing a polymerization process on a cellulose fiber structure with a hydrophilic vinyl-based monomer and performing a weight reduction process before or after the polymerization process. SOLUTION: This fiber structure is obtained by impregnating an aqueous solution of pH6-12 containing 10-30wt.% concentration of a hydrophilic vinyl- based monomer such as 2-acrylamide-2-methylapropane sulfonic acid (salt) and 1-5wt.% polymerization initiator such as ammonium persulfate based on the monomer to a finished and bleached cotton woven fabric, then heat-treating at 80-200 deg.C for polymerization processing at 1-20wt.% monomer reaction ratio. By further performing a weight reduction processing by a cellulose decomposing enzyme of 1-30g/l concentration at 3-20wt.% reduction ratio before or after the polymerization process, physical properties of >=0.0001 and <=0.005 (B/W) ratio of a bending stiffness (B) (KES method) to a unit weight (W), preferably <=0.004 and more preferably <=0.003, and a difference between moisture absorbing ratios (ΔMR) at 30 deg.C and at RH 90% to at 20 deg.C and at RH 65% of 4<ΔMR<=14, are attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber structure composed of cellulose fibers, which has an excellent hygroscopic property and a soft texture, and a method for producing the same.

[0002]

2. Description of the Related Art Cellulose fibers are known as a typical fiber having hygroscopicity, but in recent years, higher hygroscopicity has been demanded to improve comfort. For this purpose, a process of polymerizing and modifying a hydrophilic vinyl-based monomer into a fiber structure composed of cellulose fibers can be considered. However, in such a technique, the compound produced by the polymerization is present in the fiber, so that the texture of the fiber structure tends to be hardened.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to overcome the problems of hardening the texture due to the processing for improving the hygroscopicity as described above, and to provide a fiber structure composed of cellulose fibers, which is not available in the past. It is to obtain a fiber structure having a high hygroscopicity and a highly flexible texture, and a method for producing the same.

[0004]

The present invention has the following configuration to achieve the above object.

That is, in a fiber structure composed of cellulose fibers, hydrophilic cellulose monomers are polymerized in the cellulose fibers, and KES (Kawabata Evaluatio) is used.
The fiber structure is characterized in that the ratio B / W between the flexural rigidity measurement value (B) and the basis weight (W) measured by n System) is 0.0001 or more and 0.005 or less.

The method for producing a fiber structure of the present invention is
It has the following configuration.

That is, the fiber structure made of cellulose fibers is subjected to a weight reduction process before or after a polymerization process in which a heat treatment is carried out after an impregnation process of an aqueous solution containing a hydrophilic vinyl monomer and a polymerization initiator. And a method for manufacturing a fiber structure.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

In the present invention, the cellulose fibers include, but are not limited to, natural cellulose fibers such as cotton and hemp, and regenerated cellulose fibers such as rayon, polynosic, cupra and tencel. The fiber structure composed of cellulose fibers may be a woven fabric, a knitted fabric or a non-woven fabric substantially composed of cellulose fibers, or a sewing product thereof.

The fibrous structure of the present invention comprises a cellulose fiber in which a hydrophilic vinyl monomer is polymerized.

In the present invention, the hydrophilic vinyl type monomer has a polymerizable vinyl group in its molecular structure, and has an acidic group such as carboxylic acid and sulfonic acid and / or its salt, hydroxyl group, amide group and the like. A monomer having a hydrophilic group.

Concretely, acrylic acid monomers such as acrylic acid, sodium acrylate, aluminum acrylate, zinc acrylate, calcium acrylate and magnesium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, methacrylic acid. , Allyl alcohol, sodium allyl sulfonate, acrylamide, sodium vinyl sulfonate, sodium methallyl sulfonate, sodium styrene sulfonate and the like can be used. These may be used alone, or 2
More than one species may be used in combination.

Among these, 2-acrylamide-2
-A monomer containing sulfonic acid and / or its salt in the molecular structure of methyl propane sulfonic acid and / or its sodium salt, sodium allyl sulfonate, etc.,
It is preferable in terms of excellent reactivity.

The reaction rate of the hydrophilic vinyl-based monomer with respect to the fiber structure is preferably 1% by weight or more and 20% by weight or less from the viewpoint of obtaining excellent hygroscopicity while maintaining good texture of the fiber structure. . It is more preferably 3% by weight or more and 17% by weight or less, and further preferably 5% by weight or more and 15% by weight or less. The reaction rate as used herein means the proportion (% by weight) of the weight of the fiber structure increased by the polymerization of the hydrophilic vinyl-based monomer.
0 × [(absolute dry weight of fiber structure after polymerization of hydrophilic vinyl monomer)-(absolute dry weight of fiber structure before polymerization of hydrophilic vinyl monomer)] / (hydrophilic vinyl It is calculated from the absolute dry weight before the polymerization of the system monomer).

The fiber structure of the present invention has a temperature of 30.
Moisture absorption rate MR2 of fiber structure at ℃ and humidity of 90%
ΔMR represented by the value obtained by subtracting the moisture absorption rate MR1 (%) of the fiber structure at a temperature of 20 ° C. and a humidity of 65% from (%)
However, it is preferable that the following formula is satisfied.

4 <ΔMR ≦ 14 The moisture absorption rate MR1 (%) of the fiber structure at a temperature of 20 ° C. and a humidity of 65% can be considered to be the hygroscopicity of the clothes under a standard environment. The moisture absorption rate MR2 (%) of the fiber structure at a temperature of 30 ° C. and a humidity of 90% is
It can be considered as the hygroscopicity of clothes after light exercise.

The ΔMR of a fiber structure composed of only cellulose fibers not polymerized with a hydrophilic vinyl monomer is 4 at most.
It is.

On the other hand, the fiber structure of the present invention has a ΔMR of more than 4 because the hydrophilic vinyl-based monomer is polymerized on the cellulose fiber, which is more than that of the conventional fiber structure composed of only cellulose fiber. And exhibits excellent hygroscopicity.

Here, "the hydrophilic vinyl-based monomer is polymerized on the cellulose fiber" means that the hydrophilic vinyl-based monomer is graft-polymerized on the cellulose fiber, and that the inside of the void (the hollow portion or the like) of the cellulose fiber is It means that the hydrophilic vinyl-based monomer is radically polymerized or that the hydrophilic vinyl-based monomer is radically polymerized inside the cellulose single fiber. The fact that the hydrophilic vinyl-based monomer is graft-polymerized or radical-polymerized in the voids of the cellulose fibers or inside the cellulose monofilaments makes the hygroscopic durability exceptional and does not hinder the texture of the woven or knitted fabric. preferable. The polymerization of the hydrophilic vinyl-based monomer can be confirmed by, for example, a section staining method. The section staining method is performed as follows. A paraffin-embedded fiber bundle is cut in the direction perpendicular to the fiber axis to prepare a section. This section is deembedded with an organic solvent or the like, then stained with an appropriate dye (for example, a basic dye), and washed with water. The presence of the hydrophilic vinyl polymer can be confirmed by observing this with an optical microscope.

In the present invention, KES (Kawabata Evalu
ation system) is a KES bending property measuring machine (Kato), as described in Tokuo Kawabata, Textile Machinery Society of Japan (Textile Engineering), vol.26, No.10, P721-P728 (1973). TEC) is used to measure the repulsive force at each curvature when the fiber structure is bent. Then, the average value of the repulsive force between the curvatures of 0.5 and 1.5 is B (unit: g · cm ²
/ Cm), and further, this measurement is performed in each of two directions of the fiber structure, that is, the longitudinal direction and the lateral direction, and the average value is defined as B.
The ratio B / W between the value of B and the basis weight W (unit: g / m ² ) of the fiber structure is obtained.

The fiber structure of the present invention has the KES (Kawa)
The ratio B / W of the bending stiffness measurement value (B) and the basis weight (W) measured by the bata Evaluation System) is 0.0001 or more.
It should be 005 or less.

B / W by this KES measurement is 0.005
If it exceeds, the texture becomes hard and the quality deteriorates. This B / W is preferably 0.004 or less, and 0.
It is more preferably 003 or less.

Next, the method for producing the fiber structure of the present invention will be described.

A fiber structure obtained by weaving or knitting a woven fabric, a knitted fabric, or a non-woven fabric made of cellulose fibers is impregnated with an aqueous solution containing a hydrophilic vinyl monomer and a polymerization initiator, and then heat treated. The fiber structure of the present invention can be obtained by weight reduction processing before or after the polymerization processing of applying.

As a method of impregnating a fiber structure composed of cellulose fibers with an aqueous solution containing a hydrophilic vinyl monomer and a polymerization initiator, for example, a method of dipping for a certain period of time or a method of padding can be adopted. The impregnation temperature is not particularly limited and may be room temperature.

In the present invention, a polymerization initiator generally used in radical polymerization is preferably used as the polymerization initiator. Specifically, peroxides such as ammonium persulfate and benzoyl peroxide, azo catalysts and cerium catalysts are preferably used.

The concentration of the hydrophilic vinyl-based monomer in the aqueous solution containing the hydrophilic vinyl-based monomer and the polymerization initiator is
Although not particularly limited, a concentration of 10% by weight or more and 30% by weight or less is preferable from the viewpoint of efficiently carrying out the reaction. 13% by weight
It is more preferably at least 27% by weight, and even more preferably at least 15% by weight and at most 25% by weight.

The concentration of the polymerization initiator in the aqueous solution containing the hydrophilic vinyl-based monomer and the polymerization initiator is not particularly limited, but from the viewpoint of efficiently carrying out the reaction, it is 1 relative to the hydrophilic vinyl-based monomer. The content is preferably 5% by weight or more and 5% by weight or less, more preferably 2% by weight or more and 4% by weight or less.

From the viewpoint of suppressing the deterioration of strength and physical properties of the fiber structure composed of cellulose fibers and efficiently carrying out the reaction, the pH of the aqueous solution containing the hydrophilic vinyl monomer and the polymerization initiator is 6 or more and 12 or less. Is preferred, p
It is more preferable that H is 7 or more and 11 or less.

In the method for producing a fiber structure of the present invention, a heat treatment is carried out after the impregnation treatment, and the heat treatment is essential for carrying out the polymerization reaction. The heat treatment may be dry heat treatment, wet heat treatment or the like without particular limitation.

The heat treatment temperature is not particularly limited, but it is preferable to carry out the heat treatment at a temperature of 80 ° C. or higher and 200 ° C. or lower from the viewpoint of efficiently carrying out the polymerization reaction. Heat treatment is performed in one step or in two or more steps. The heat treatment time is determined in consideration of the heat treatment temperature from the relationship with the target reaction rate, but it is preferably 20 seconds or more and 5 minutes or less.

Further, in the above-mentioned polymerization process, it is preferable that after the heat treatment, washing is performed in order to remove unreacted monomers and the like adhering to the fiber structure. The washing method is not particularly limited and may be washing with water or washing with hot water, but washing with hot water can be preferably used from the viewpoint of washing efficiency. In addition, when the weight reduction processing described below is performed after the polymerization processing, the weight reduction processing also has a cleaning action.

In addition to the polymerization process, it is necessary to carry out a weight reduction process. The weight reduction processing here means a treatment of decomposing and removing a part of the fibers constituting the fiber structure to reduce the weight thereof.

Generally known as a weight-reducing method for cellulose fibers is a treatment with a cellulolytic enzyme or hydrolysis with an acid, and as a weight-reducing method for a cellulose fiber, a cellulolytic enzyme is used. Preference is given to using treatments. Cellulolytic enzymes include genus Tricoderma, genus Fumicola, genus Aspergills,
Those obtained by culturing cells of the genus Bacillus can be used. These cellulolytic enzymes are already on the market and may be used as they are.

In the present invention, the weight reduction rate of weight reduction processing is
It refers to the ratio of the portion that is decomposed and removed before and after processing, and is specifically calculated from (weight loss / weight before processing) × 100.

In the present invention, the weight loss rate is preferably 3% or more and 10% or less from the viewpoint of imparting flexibility to the fiber structure while maintaining strength.

As a method for reducing weight, for example, the fiber structure is immersed in an aqueous solution having a concentration of the aforementioned cellulolytic enzyme of 1 g / l or more and 30 g / l or less and treated at a temperature of 30 ° C. or more and 90 ° C. or less. Is preferred.

In the present invention, the order of the polymerization processing and the weight reduction processing may be such that the weight reduction processing may be performed after the polymerization processing, or conversely, the weight reduction processing may be performed first. When the weight-reducing process is performed after the polymerization process, a larger inter-fiber void is generated, so that the texture softening effect can be greatly obtained.

[0039]

EXAMPLES The present invention will be described more specifically below with reference to examples. Each characteristic value in the examples was determined by the following method.

(1) Moisture absorption rate The moisture absorption rate is the weight when the fiber structure is completely dried and the temperature of 2
It was calculated from the following formula based on the weight change from the weight after standing in a thermo-hygrostat for 24 hours in an atmosphere of 0 ° C. and 65% humidity or 30 ° C. and 90% humidity.

Moisture absorption rate (%) = 100 × [(weight of fiber structure after standing at constant temperature and humidity)-(absolute dry weight of fiber structure)] / (absolute dry weight of fiber structure) From the moisture absorption rate MR1 under the conditions of temperature 20 ° C. and humidity 65% and the moisture absorption rate MR2 under the conditions of temperature 30 ° C. and humidity 90%, ΔMR was calculated by the following equation.

ΔMR = MR2-MR1 Here, the larger ΔMR corresponds to higher hygroscopicity and better comfort.

(2) Reaction rate The reaction rate is calculated from the absolute dry weight of the fibrous structure before the polymerization of the hydrophilic vinyl-based monomer and the absolute dry weight of the fibrous structure after the polymerization of the hydrophilic vinyl-based monomer. Was calculated by the following formula.

Reaction rate (%) = 100 × [(absolute dry weight of fiber structure after polymerization of hydrophilic vinyl monomer)-
(Absolute dry weight of the fiber structure before polymerizing the hydrophilic vinyl monomer)] / (Absolute dry weight of the fiber structure before polymerizing the hydrophilic vinyl monomer) (3) Weight loss rate The weight loss rate is The absolute dry weight of the fiber structure before weight reduction processing and the absolute dry weight of the fiber structure after processing were calculated by the following formula.

Weight loss rate (%) = (absolute dry weight of fiber structure before processing-absolute dry weight of fiber structure after processing) / (absolute dry weight of fiber structure before processing) × 100 (4) B / W KES (Kawabata Evaluation System) Bending rigidity using a measuring machine, vertical mean value B (unit: g · cm ²
/ Cm) and the basis weight W (unit: g / m ² ) of the fiber structure, the ratio B / W was measured.

Example 1 Cotton fabric which had been scoured and bleached (use of yarn: 45th warp, 45th weft, plain weave, weave density: 115 warp / inch
× Weft 76 lines / inch, basis weight: 110 g / m ² ), and 20% of 2-acrylamido-2-methylpropanesulfonic acid
%, And an aqueous solution containing ammonium persulfate at a concentration of 0.6% (monomer ratio 3%) was applied by padding. The squeezing rate was 90%. Then 160 of this cotton fabric
It heat-processed at 3 degreeC for 3 minutes. After the heat treatment, it was washed with hot water at 60 ° C. Thereafter, the reaction rate was measured by the above method, and the value was 16%.

Then, the cotton fabric was dipped in a treatment solution containing a cellulolytic enzyme (Cellsoft L, manufactured by Novo Nordisk Co., Ltd.) at a concentration of 5 g / l and treated at 60 ° C. for 1 hour. As a result, the weight of the fabric was reduced by 5.2% as compared with the fabric before the enzyme treatment.

After the above-mentioned polymerization process and weight reduction process, dyeing and finishing processes are carried out by a usual method, and then the respective characteristic values are measured by the above-mentioned methods. When ΔMR = 12.0%, B is 0.3.
39 g · cm ² / cm, W is 121 g / m ² , and B
/ W was 0.0028.

On the other hand, B of the woven fabric which has not been subjected to the polymerization process and the weight reduction process and which has just been scoured and bleached is 0.880.
g · cm ² / cm, W is 110 g / m ² , B / W
Was 0.0080.

Example 2 Cotton fabric which had been scoured and bleached (use of yarn: 45th warp, 45th weft, plain weave, weaving density: 115 warp / inch
× Weft 76 lines / inch, basis weight: 110 g / m ² ), cellulolytic enzyme (CellSoft L, manufactured by Novo Nordisk)
Is immersed in a treatment liquid containing 5 g / l of the solution at 60 ° C. for 1 hour.
Time processed. As a result, the weight of the fabric was reduced by 6.5% as compared with the cotton fabric before the enzyme treatment.

Thereafter, this cotton fabric was padded with an aqueous solution containing 20% of 2-acrylamido-2-methylpropanesulfonic acid and 0.6% of ammonium persulfate (3% of monomer ratio). Squeezing rate is 90%
Met. The cotton fabric was then heat treated at 160 ° C for 3 minutes. After the heat treatment, it was washed with hot water at 60 ° C. Thereafter, the reaction rate was measured by the above method, and the value was 12%.

After the above-mentioned polymerization process and weight reduction process, dyeing and finishing processes were carried out by a usual method, and ΔMR = 8.8.
%, B is 0.346 g · cm ² / cm, W is 115
It was g / m ² and B / W was 0.0030.

Comparative Example 1 Scoured and bleached cotton fabric (yarn use: warp 45 count, weft 45 count, plain fabric, weave density: 115 warp / inch
× Weft 76 lines / inch, basis weight: 110 g / m ² ), and 20% of 2-acrylamido-2-methylpropanesulfonic acid
%, And an aqueous solution containing ammonium persulfate at a concentration of 0.6% (monomer ratio 3%) was applied by padding. The squeezing rate was 90%. Then 160 of this cotton fabric
It heat-processed at 3 degreeC for 3 minutes. After the heat treatment, it was washed with hot water at 60 ° C. Thereafter, the reaction rate was measured by the above method, and the value was 16%.

After that, when each characteristic value was measured by the above method, ΔMR = 11.5% and B was 1.177 g · cm ²
/ Cm, W is 128 g / m ² , B / W is 0.0
092. In this case, a high degree of hygroscopicity was obtained, but the flexibility was poor.

Comparative Example 2 Cotton fabric that has been scoured and bleached (yarn use: warp yarn 45 count, weft yarn 45 count, plain fabric, weave density: warp 115 yarns / inch
× Weft 76 lines / inch, basis weight: 110 g / m ² ), cellulolytic enzyme (CellSoft L, manufactured by Novo Nordisk)
Is immersed in a treatment liquid containing 5 g / l of the solution at 60 ° C. for 1 hour.
Time processed. As a result, the weight of the fabric was reduced by 7.5% as compared with the cotton fabric before the enzyme treatment.

After that, each characteristic value was measured by the above method, and ΔMR = 3.4%, and B was 0.275 g · cm ² /
cm, W is 102 g / m ² , B / W is 0.00
27. This treatment provided flexibility, but was inferior in hygroscopicity.

Examples 3 to 6 The same procedure as in Example 1 was carried out except that the kind of hydrophilic vinyl type monomer was changed. The results are shown in Table 1. All had high hygroscopicity and flexibility.

[0058]

[Table 1] Examples 7 to 10 pH of aqueous solution containing hydrophilic vinyl monomer and initiator
Same as Example 1 except that was changed. Table 2 shows the results. All had high moisture absorption and flexibility.

[0059]

[Table 2] Examples 11 to 14 The procedure of Example 1 was repeated, except that the concentration of the hydrophilic vinyl-based monomer in the aqueous solution was changed. The results are shown in Table 3.
All had high hygroscopicity and flexibility.

[0060]

[Table 3] Examples 15 to 18 The procedure of Example 1 was repeated, except that the concentration of the initiator was changed with respect to the hydrophilic vinyl monomer. The results are shown in Table 4. All had high hygroscopicity and flexibility.

[0061]

[Table 4] Examples 19 to 22 The same procedure as in Example 1 was performed except that the heat treatment temperature was changed. Table 5 shows the results. All had high hygroscopicity and flexibility.

[0062]

[Table 5]

[0063]

EFFECTS OF THE INVENTION According to the present invention, it is possible to provide a fiber structure which can be widely used for clothing because it has excellent hygroscopicity and therefore has excellent comfort when worn and is excellent in flexibility.

Claims (15)

[Claims] 1. A fiber structure composed of cellulose fibers, wherein hydrophilic cellulose-based monomers are polymerized on the cellulose fibers, and KES (Kawabata Evaluation System) is used.
Ratio of measured flexural rigidity (B) and basis weight (W) B /
W is 0.0001 or more and 0.005 or less, The fiber structure characterized by the above-mentioned. 2. A value obtained by subtracting the moisture absorption rate MR1 (%) of the fiber structure at a temperature of 20 ° C. and a humidity of 65% from the moisture absorption rate MR2 (%) of the fiber structure at a temperature of 30 ° C. and a humidity of 90%. The fibrous structure according to claim 1, wherein ΔMR satisfies the following formula. 4 <ΔMR ≦ 14 3. The fiber structure according to claim 1, wherein the reaction rate of the hydrophilic vinyl-based monomer with respect to the fiber structure is 1% by weight or more and 20% by weight or less. 4. The fiber structure according to claim 1, wherein the hydrophilic vinyl-based monomer is a vinyl-based monomer containing sulfonic acid and / or sulfonate. 5. The fiber structure according to claim 1, wherein B / W is 0.0001 or more and 0.004 or less. 6. The fiber structure according to claim 1, wherein B / W is 0.0001 or more and 0.003 or less. 7. A weight-reducing process of a fibrous structure composed of cellulose fibers before or after a polymerization process in which a heat treatment is performed after impregnation with an aqueous solution containing a hydrophilic vinyl monomer and a polymerization initiator. And a method for manufacturing a fiber structure. 8. The method for producing a fiber structure according to claim 7, wherein the hydrophilic vinyl-based monomer is a vinyl-based monomer containing a sulfonic acid and / or a sulfonate. 9. The method for producing a fiber structure according to claim 7, wherein the pH of the aqueous solution is 6 or more and 12 or less. 10. The method for producing a fiber structure according to claim 7, wherein the concentration of the hydrophilic vinyl-based monomer in the aqueous solution is 10% by weight or more and 30% by weight or less. 11. The method for producing a fiber structure according to claim 7, wherein the polymerization initiator is contained in an amount of 1% by weight or more and 5% by weight or less with respect to the hydrophilic vinyl-based monomer. 12. The method for producing a fiber structure according to claim 7, wherein the heat treatment temperature is 80 ° C. or higher and 200 ° C. or lower. 13. The method for producing a fiber structure according to claim 7, wherein the weight loss rate is 3% or more and 20% or less. 14. The method for producing a fiber structure according to claim 7, wherein the weight-reduction processing is weight-reduction processing of cellulose fibers with a cellulolytic enzyme. 15. The concentration of the cellulolytic enzyme is 1 g /
The method for producing a fiber structure according to claim 14, wherein the fiber structure is immersed in an aqueous solution of 1 or more and 30 g / l or less and treated at a temperature of 30 ° C or more and 90 ° C or less.