JP2006045722A - Fiber structure and method for bleaching treatment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for bleaching, using an oxygen-based bleaching agent and for artificial cellulose fiber-containing fibrous structure whose strength is hardly decreased even when bleached at an oxygen-based bleaching agent concentration of making whiteness of CIELab (color space) method of natural fiber ≥65, and to provide a fibrous structure obtained by using the method. <P>SOLUTION: The fiber structure comprises natural fiber and artificial fiber and has ≥65 whiteness of CIELab method and ≤25% decrease of strength between before and after bleaching treatment, wherein, preferably, no fluorescent dye is contained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fiber structure and a processing method thereof, and more particularly to a bleached artificial cellulose fiber-containing fiber structure and a bleaching method thereof.

Conventionally, fiber structures such as woven and knitted fabrics made of natural fibers such as cotton, hemp and silk have been bleached for the purpose of improving dyeability not only in the production process of white products but also in the pretreatment process of dyeing processing. However, recently, in consideration of the environment and equipment in particular, bleaching treatment using an oxygen-based bleaching agent is more frequently used than a chlorine-based one. For example, the hydrogen peroxide concentration when bleaching cotton with hydrogen peroxide by the batch method is 0.5 to 1.5%, and the treatment temperature is 90 to 100 ° C. (described in Non-Patent Documents 1 and 2). ).
On the other hand, fiber structures made of artificial cellulose fibers such as viscose rayon, cupra / ammonium rayon, polynosic rayon, and refined cellulose fibers (Tencel, Lyocell) are strongly reduced by bleaching, so they are low only in the required product fields. For example, the hydrogen peroxide concentration in the hydrogenation bleaching of cupra ammonium rayon in a batch method is 0.08 to 0.1% (0.8 to 1.0 g / L), the treatment The temperature is 70 to 75 ° C. (described in Non-Patent Document 1). Incidentally, when cupra ammonium rayon is bleached at a hydrogen peroxide concentration of 1.5%, the strength is reduced by 30 to 60%.

  When natural fibers and artificial cellulose fibers are combined, the natural fibers have high bulkiness and high wet strength, and the artificial cellulose fibers have high moisture absorption, high water absorption, gloss, slipperiness, and irritation to the skin. However, when these composite fabrics are subjected to oxygen bleaching, if bleaching is performed with an oxygen bleaching agent concentration at which natural fibers are sufficiently white, artificial cellulose fibers are extremely damaged. When bleaching is performed with an oxygen bleach concentration that does not cause a strong decrease in the strength of artificial cellulose and the artificial cellulose, there is a problem that natural fibers become insufficiently bleached.

  As an example of improving the whiteness in oxygen-based bleaching of a conventional woven or knitted fabric made of natural fibers, there is an example in which a hydrogen peroxide stabilizer is used when performing hydrogen peroxide bleaching (described in Patent Document 1). In Patent Document 1, it is obtained by radical polymerization of at least one monomer selected from the group consisting of acrylic acid, methacrylic acid, maleic acid and salts thereof, and poly-α-hydroxyacrylic acid and / or a salt thereof. Using a hydrogen peroxide stabilizer containing a polymer and a water-soluble magnesium compound, wherein the weight ratio of the polymer to magnesium is 1: 1 to 45: 1, even in the presence of a high concentration of alkali. It is described that the bleaching performance is maintained and the whiteness of the fibers is improved.

  However, even if a hydrogen peroxide stabilizer is used in combination with a fabric in which natural fibers and artificial cellulose fibers are combined, if bleaching is performed at an oxygen-based bleaching concentration sufficient to obtain sufficient whiteness for natural fibers, it will eventually be Manufactured cellulose fibers cause a decrease in strength, and as long as bleaching is performed at a concentration that does not cause the strength of the artificial cellulose fibers to decrease, whiteness sufficient to obtain sufficient whiteness for natural fibers, even if stabilizers are used. The improvement effect cannot be obtained.

Further, as an example of improving the bleaching effect, for example, there is an example (described in Patent Document 2) in which an activator is used when performing hydrogen peroxide bleaching. In Patent Document 2, hydrogen peroxide and / or a hydrogen peroxide additive, a nitrogen-containing heteroalicyclic compound in which the hydrogen atom of the second amino group in the heterocyclic ring is substituted with a halogen atom, or non-heterocyclic N A halo-hindered amine compound, the hydrohalous acid formation hydrolysis equilibrium constant of which is at least one activator in the range of 1 × 10 ^{−10 to} 5 × 10 ⁻⁶ (25 ° C.) By performing hydrogen peroxide bleaching using a bleaching composition characterized by the fact that it improves the bleaching effect at low temperatures, exhibits excellent bleaching effect even at low temperatures, and discolors color patterns It is described to provide a bleach composition that is very unlikely to occur.

However, the method described in Patent Document 2 is effective for bleaching substances in the fiber surface layer portion such as stain stains, but yellow substances such as lignin existing in cotton cannot be sufficiently bleached, It is difficult to obtain sufficient whiteness. In the method described in Patent Document 2, the material to be treated is put into a bleaching bath without being wetted with water or the like in advance. For example, cupra and ammonium rayon remain in a dry state and are put into an alkaline bath. When it is thrown in, it causes rapid swelling and shrinkage, and as a result, wrinkles and texture changes occur. However, there is no description on a processing method for preventing this.
In order to increase the whiteness of these fabrics, fluorescent dyeing may be performed after bleaching or at the same time as bleaching. However, fabrics that have been fluorescently dyed have a problem of fading due to the low light fastness of fluorescent dyes. There is.

Like these, it is not possible to produce white products by bleaching fabrics that are a combination of natural fibers and artificial cellulose fibers that require bleaching with high-concentration bleaching agents such as cotton, hemp, and silk with oxygen-based bleaching agents. So far it has been very difficult.
Written by Shigeru Hayashi et al., Dyeing Course 4 -Scouring / Bleaching and Dyeing I-, Kyoritsu Publishing Co., Ltd., issued November 1, 1965, pages 32,62 Textile Engineering Publication Committee, Textile Engineering [V] dyeing finish, Japan Textile Machinery Society, October 30, 1984, 18, 19 JP 2003-095622 A Japanese Patent Publication No. 08-013996

  An object of the present invention is to solve the above-mentioned problems of the prior art and provide an artificial cellulose fiber-containing fiber structure in which the strength of the artificial cellulose fiber is little reduced even when bleaching is performed at a high concentration of oxygen bleach. There is.

As a result of intensive studies on the above problems, the present inventors have reached the present invention.
That is, the invention claimed in the present application in order to achieve the above-described problems is as follows.
(1) A fiber structure containing natural fibers and artificial cellulose fibers, having a whiteness in the CIELab method of 65 or more, and a strength reduction rate of the artificial cellulose fibers before and after bleaching treatment is 25% or less .
(2) The fiber structure according to the above (1), which does not contain a fluorescent dye.
(3) A method for bleaching a fiber structure, wherein a radical scavenger is used when a fiber structure containing natural fibers and artificial cellulose fibers is bleached with an oxygen bleach.
(4) The above (3), wherein the whiteness of the fiber structure after bleaching in the CIELab method is 65 or more and the strength reduction rate of the artificial cellulose fiber before and after bleaching is 25% or less. For bleaching fiber structures.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a fiber structure containing a natural fiber and an artificial cellulose fiber, which has little decrease in strength of the artificial cellulose fiber even after bleaching with a high concentration oxygen bleach.

The present invention is described in detail below. The fiber structure of the present invention comprises natural fibers such as cotton, hemp and silk, viscose rayon, cupra ammonium rayon, polynosic rayon, purified cellulose fibers (Tencel, Lyocell), cellulose acetate fibers (cellulose diacetate, cellulose triacetate). ) And other artificial cellulose fibers.
In order to have both the characteristics of the natural fiber and the specification of the artificial cellulose fiber, the mixing ratio of the artificial cellulose fiber to the natural fiber is preferably 10 to 90%, more preferably 30 to 70%.
The form of the fiber structure is not particularly limited. For example, any form such as a woven or knitted fabric, a non-woven fabric, and a fiber product, cotton, yarn, etc. may be used. .

The shape of the fiber may be long fiber or short fiber, and may be uniform or thick in the length direction, and round, triangular, L, T, Y, W, Leaf type, flatness (with a flatness of about 1.3-4, W type, I type, Boomerang type, wave type, skewer type, eyebrows type, rectangular parallelepiped type, etc.), dogbone type, etc. Polygon type, multi-leaf type, hollow type and irregular shape may be used.
Furthermore, the yarn forms include ring spun yarn, open-end spun yarn, air jet fine spun yarn, multifilament yarn, sweet-twisted yarn to strong twisted yarn, false twisted yarn, air jet yarn, indented yarn Knitted and knitted yarn. In particular, for false twisted yarn, for example, a cellulose crimp false twist yarn described in JP-A-2002-327343 can be used.

  In addition, the synthetic fiber other than the natural fiber and the artificial cellulose fiber, such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, and the like, usually within a range of 50% by mass or less within a range not impairing the object of the present invention. Various synthetic fibers such as polyester fibers, nylon fibers such as nylon 6 and nylon 66, elastic fibers such as acrylic fibers, polyurethane fibers, and the like, as well as their copolymer types and composite fibers using the same or different polymers (side-by-side type) 1 type or 2 or more types of synthetic fibers such as eccentric sheath and core type) (blend cotton, fleece blend, sliver blend, core yarn, silo span, silofill, hollow spindle, etc.), blend (boiling water shrinkage 3-10) % Low shrinkage yarn, boiling water shrinkage rate of 15-30% high shrinkage yarn and even different Including mixed yarn with compressed mixed yarn), cross-twisted, various twisted yarn, design twisted yarn, covering (single, double), composite false twist (simultaneous false twist, first twist false twist (first twist same direction false twist or first twist) Different direction false twists), phase difference false twists, post-mixing after false twisting, and two-feed (simultaneous feed or feed difference added) air injection processing may be used.

The whiteness in the CIELab method refers to the whiteness of the fabric when colorimetry is performed by setting the colorimeter to include the light source C, specular gloss, and the ultraviolet region of the light source, and setting the field of view to 2 degrees. The fiber structure of the present invention has a whiteness by the CIELab method of 65 or more, preferably 67.5 or more.
The strength reduction rate of the artificial cellulose fiber before and after the bleaching treatment in the fiber structure of the present invention is the artificial cellulose fiber sample extracted from the fiber structure before the bleaching treatment, and the artificial cellulose extracted from the fiber structure after the bleaching treatment. The fiber sample was conditioned at a temperature of 20 ° C. and a humidity of 65 RH% for one day, then the strength was measured, and the difference in strength before and after bleaching was divided by the strength of the fabric before bleaching. Formula (1) Indicated by
Strength reduction rate (%) = {(Strength before bleaching-Strength after bleaching) / Strength before bleaching} × 100
... (1)
Here, the strength before bleaching indicates the strength of the sample extracted from the fiber structure before bleaching, and the strength after bleaching indicates the strength of the sample extracted from the fiber structure after bleaching.

The strength reduction rate of the artificial cellulose fiber before and after the bleaching treatment in the fiber structure of the present invention is characterized by 25% or less. Preferably it is 22.5% or less, More preferably, it is 20% or less.
A suitable bleaching method for obtaining the fiber structure of the present invention in which the whiteness by the CIELab method is 65 or more and the strength reduction rate of the artificial cellulose fiber before and after the bleaching treatment is 25% or less is described below.

The bleaching method in the present invention can be carried out by either a batch method or a continuous method, but is preferably carried out by a batch method. In addition, as the bleaching machine used in the present invention, it is possible to use a batch type bleaching machine such as wins, overmeyer, and jigger, and a continuous type bleaching machine such as a continuous bleaching machine such as J-box, L-box, and purple range. However, it is preferable to use a batch bleaching machine.
As the bleaching agent, oxygen-based bleaching agents such as hydrogen peroxide, sodium peroxide, sodium perborate, potassium permanganate, and peracetic acid are preferably used, and hydrogen peroxide is particularly preferred.

  What is necessary is just to perform the bleaching agent density | concentration and bleaching temperature in this invention on the conditions of the fiber structure which consists of general natural fiber. The oxygen bleach concentration is preferably in the range of 15 to 70 g / liter (1.5 to 7.0%) in the continuous method and 5 to 15 g / liter (0.5 to 1.5%) in the batch method. The bleaching temperature is preferably 60 ° C. or higher and 100 ° C. or lower, more preferably 80 ° C. or higher and 100 ° C. or lower. What is necessary is just to set a bleaching time suitably according to bleaching temperature, Preferably it is 15 to 120 minutes, More preferably, it is 20 to 60 minutes. The bath ratio may be appropriately set depending on the bleaching machine to be used, but in the case of a batch type bleaching machine, it is preferably 1:15 to 1:50, more preferably 1:15 to 1:30. The temperature raising rate may be set within a range that does not cause any problems in the performance of the bleaching machine, and is preferably 2 to 5 ° C./min.

The fiber structure of the present invention can be suitably obtained by using a radical scavenger when bleaching with an oxygen-based bleach. The radical scavenger used in the present invention is not particularly limited as long as it captures hydroxy radicals generated in a bath during oxygen bleaching, but preferably a hindered or amine radical. It is a scavenger. The radical scavenger can be used at a temperature from room temperature to 100 ° C. The addition to the bath may be performed until the bleaching temperature is reached, but it is preferably performed at the start of bleaching.
The radical scavenger may be added in an amount that can supplement the hydroxyl radicals generated by the bleaching bath ratio and oxygen bleach concentration. Although there is no restriction | limiting in particular in the upper limit which adds a radical scavenger, Preferably it is 5 to 100 weight% with respect to the addition amount of an oxygen type bleaching agent, More preferably, it is 15 to 80 weight%. When the addition amount is 5% by weight or less based on the bleaching agent, the effect of preventing the strength reduction of the artificial cellulose fiber becomes insufficient. Excessive addition is not preferable in practice.

  In the present invention, additives that can be added to the oxygen bleaching system include alkali components represented by caustic soda, soda ash, aqueous ammonia, hydrogen peroxide bleach stabilizer (silicate, phosphate). , Polycarboxylic acids and complex salt-forming substances), chelating agents (aminocarboxylic oxygen, polymerized phosphoric acid, etc.), chelating dispersants, penetrants, antifoaming agents, etc. I can do it.

  In the present invention, it is more preferable to wet the artificial cellulose-containing fiber structure in water before bleaching. Although the water temperature in that case is not specifically limited, Preferably it is 100 degrees C or less. If the artificial cellulose fiber structure is put into a bleaching bath in a dry state, the artificial cellulose fiber may suddenly swell or shrink due to the influence of alkali or the like, resulting in the occurrence of wrinkles or texture changes. is there. The wetting method is not particularly limited. For example, when performing batch processing using hydrogen peroxide, the fiber structure is introduced into a bleaching machine into which water has been added in advance, and the dough is sufficiently moistened and relaxed. , Radical scavenger and hydrogen peroxide in this order.

The present invention is effective in cases where only bleaching is performed or in cases where scouring and bleaching or bleaching and fluorescent dyeing are carried out simultaneously, but a sufficient bleaching effect can be obtained without carrying out fluorescent dyeing. The fiber structure of the present invention which is not subjected to fluorescent dyeing and does not contain a fluorescent dye is preferable because it has the advantage that there is no fading problem due to the low light fastness of the fluorescent dye. There are no particular restrictions on the scouring agent, the fluorescent dye, and the dyeing assistant in the case of refining and fluorescent dyeing, and any of them can be used as usual together with the radical scavenger.
When the dough obtained after bleaching according to the present invention is dyed, it can be carried out as usual.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Evaluation of the processed product after bleaching was performed as follows.
1) Color measurement of treated material For fabrics bleached with hydrogen peroxide, using COLOR-EYE 3000 spectrophotometer (Macbeth Co., Ltd.), including light source C, specular gloss, UV region of light source, and setting the field of view to 2 degrees Color difference formula: Whiteness (WI value) was measured by the CIELab method. The higher the whiteness value, the higher the whiteness of the fabric.
2) Tensile strength measurement For fabrics before and after bleaching with hydrogen peroxide, the strength of artificial cellulose fiber yarns was measured at a temperature of 20 ° C and humidity of 65 RH using Tensilon RTM-100 (manufactured by Orientec Corporation). % In an environment.
3) Comprehensive evaluation The items 1) to 2) were comprehensively determined as follows.
A: Very good.
○: Excellent.
×: unsuitable

[Example 1]
Cupra-ammonium rayon yarn (Asahi Kasei Fibers Co., Ltd. Bemberg) 168 dtex / 90f and cotton 60 /-, using a large moat 24G 30 inch, a cupra-ammonium rayon yarn on the fabric surface and cotton on the back Organized. The loop length was 3.0 mm / eye.
Next, 1000 g of the knitted fabric is put into a wins dyeing machine together with 15 L of soft water to sufficiently wet the knitted fabric, and then 19.5 g of a hydrogen peroxide bleach stabilizer (Neolate PH-55F, manufactured by Nikka Chemical), a radical scavenger. (Credit PO from Nikka Chemical Co., Ltd.) 45g, 35% hydrogen peroxide solution 150g was added in this order, and bleaching treatment with hydrogen peroxide was performed under the conditions of bleaching temperature 95 ° C, bleaching time 30 minutes, heating rate 3 ° C / min. It was.
The bleached dough was put into a treatment liquid in which 15 ml of acetic acid (special grade made by Wako Pure Chemical Industries) was added to 15 L of soft water and treated at a treatment temperature of 50 ° C. for a treatment time of 20 minutes.
As a result, a knitted fabric bleached white and having no change in texture was obtained. Table 1 shows the results of measuring the strength and elongation of the cupra-ammonium rayon yarn obtained by colorimetry and knitting the obtained knitted fabric, and the composite fabric has sufficient whiteness. It was also confirmed that the strength reduction rate of the cupra / ammonium rayon yarn was extremely small.

[Example 2]
When performing hydrogen peroxide bleaching, the treatment was performed in the same manner as in Example 1 except that 40 g of sodium carbonate (special grade manufactured by Wako Pure Chemical Industries) was used instead of the hydrogen peroxide bleach stabilizer.
As a result, a knitted fabric bleached white and having no change in texture was obtained. Table 1 shows the results of measuring the strength and elongation of the cupra-ammonium rayon yarn obtained by colorimetry and knitting the obtained knitted fabric, and the composite fabric has sufficient whiteness. It was also confirmed that the strength reduction rate of the cupra / ammonium rayon yarn was extremely small.

[Comparative Example 1]
When performing hydrogen peroxide bleaching, the treatment was performed in the same manner as in Example 1 except that no radical scavenger was added.
As a result, a white knitted fabric was obtained. Table 1 shows the results of measuring the strength and elongation of the cupra-ammonium rayon yarn by measuring the color of the obtained knitted fabric and deniting the knitted fabric.・ Strong elongation of ammonium rayon yarn was greatly reduced to a level that was not practical.

[Comparative Example 2]
When performing hydrogen peroxide bleaching, the same treatment as in Example 1 was performed except that 15 g of 35% hydrogen peroxide water was added and no radical scavenger was added.
As a result, a yellowish knitted fabric was obtained. Table 1 shows the results of measuring the strength and elongation of the cupra / ammonium rayon yarn by measuring the color of the obtained knitted fabric and deniting the knitted fabric. The whiteness of was not getting enough whiteness.

  The processing method of the present invention and the fiber structure obtained thereby are oxygen-based composites of natural fibers and artificial cellulose fibers represented by cotton and the like, in which the whiteness of the natural fibers is 65 or more. Bleaching can be performed at a bleaching agent concentration, whereby a new fiber structure can be produced.

Claims (4)

  A fiber structure comprising natural fibers and artificial cellulose fibers, having a whiteness in the CIELab method of 65 or more and a strength reduction rate of the artificial cellulose fibers before and after bleaching treatment is 25% or less.   2. The fiber structure according to claim 1, which does not contain a fluorescent dye.   A method for bleaching a fiber structure, wherein a radical scavenger is used when a fiber structure containing natural fibers and artificial cellulose fibers is bleached with an oxygen bleach.   4. The fiber structure according to claim 3, wherein the whiteness of the fiber structure after bleaching in the CIELab method is 65 or more and the strength reduction rate of the artificial cellulose fiber before and after the bleaching treatment is 25% or less. Bleaching method.