KR100472383B1 - Y-shaped rayon fiber and method for producing it - Google Patents

Abstract

The present invention relates to a method for producing rayon fibers of Y-type cross-section from cellulose acetate fibers of Y-type cross section. According to the present invention, it can be produced in a simple manufacturing process, low production cost and safe operating conditions and is similar to viscose rayon fibers. This makes it possible to provide rayon fiber which is very suitable for clothing use and has excellent shari feeling.

Description

Y-shaped rayon fiber and method for producing it

The present invention relates to a rayon fiber of the Y-type cross section, and more particularly, to a cellulose rayon fiber of the Y-type cross section made from cellulose acetate fibers and a method for producing the same.

Here, the rayon fiber is defined as a fiber made of a polymer of beta-D-glucopyranose (hereinafter referred to as cellulose) in which a hydroxyl group is not substituted by 15% or more.

Conventional rayon fibers, such as viscose rayon, cupraammonium rayon, Schömberg rayon, high-strength rayon, and fortisic acid (high-strength rayon made from the selenium acetate of Seleniz) have a cellulose II crystal structure (see, for example, PH Hermans, Makromolecules). , Chem., Vol. 6, pp 25-29 and J. Dyer and GC Daul, Handbook of Fiber Science and Technology: Volume IV (Edited by M. Lewin and EM Pearce; Fiber Chemistry, p968, Marcel Dekker 1985).

Viscose rayon is prepared by spinning cellulose into an aqueous solution of sodium cellulose xanthate using aqueous caustic soda and carbon disulfide (CS ₂ ) and then spinning it into an aqueous solution of sulfuric acid and zinc sulfate. At this time, it is very difficult to produce a uniformly colored textile product due to the dyeing difference between the inner and outer layers of the same fern, as well as emitting substances that are very harmful to the human body, such as carbon disulfide during the manufacturing process.

Lyocell fiber, which was spun by dissolving cellulose in N-methylmorpholine-N-oxide, was rather stiff and expensive to use as a textile product. It is used for clothing.

Conventionally, a method of producing fortic acid, manufactured by Celannese, which is a method of preparing rayon using cellulose acetate as a raw material (see Robert W. Work, TEXTILE RESEARCH JOURNAL, Vol. ⅩⅨ, No. 7, pp 381-393, July 1949) and U.S. Patent No. 2,053,766, which has a high strength (more than 2.5gf / de strength) rayon production method. These are drawn after stretching the acetate fibers and then saponified with alkali to produce rayon having a cellulose II crystal structure. The rayon fiber made in this way has been improved in strength, but its elongation is less than 10%, limiting its use to industrial use.

Accordingly, an object of the present invention is to provide a rayon fiber having a cellulose acetate as a raw material similar to viscose rayon in physical properties and having a Y-shaped cross section.

According to the present invention for achieving the above object, the cellulose acetate by alkali treatment of a fiber or a textile product containing at least a portion of cellulose acetate fibers having a degree of substitution of 2.0 to 2.75 (superoxidation degree of 45 to 59.5%) and having a Y-shaped cross section. A method for producing a Y-type cross-section rayon fiber is provided, comprising the step of converting at least 75% of the total acetyl groups of the fiber into a hydroxyl group to convert the cellulose II crystal structure and the cellulose IV crystal structure into a mixed rayon fiber. .

In addition, according to the present invention is characterized by containing the Y-type cross-sectional rayon fiber prepared by the above-described method, the cut strength is 2.5gf / de or less, the cut elongation is more than 20%, the cellulose II crystal structure and cellulose IV crystal structure mixed Y-shaped cross-section rayon fiber is provided.

Hereinafter, the present invention will be described in more detail.

According to the present invention, cellulose II crystals are obtained by alkali treating cellulose acetate fibers having a degree of substitution of 2.0 to 2.75 (45 to 59.5% of superoxide) and alkalinizing at least 75% of all acetyl groups with a hydroxyl group. The structure and the cellulose IV crystal structure are converted into a mixed Y-type cross-section rayon fiber.

According to the present invention, a preferred example of a method of converting the cellulose acetate fibers of the Y-shaped cross section into the rayon fibers of the Y-shaped cross section is alkali, knitted fabric containing only the cellulose acetate fibers of the Y-shaped cross section, for example, the acetate fibers alone. A method of alkali treating a knitted fabric composed of a knitted fabric, a knitted fabric composed of the acetate fiber and another fiber, or a knitted knitted fabric composed of the acetate fiber and the other fiber; Alkali-treated only cellulose acetate fibers of Y-shaped cross section; The cellulose acetate fiber of a Y-type cross section, etc. alkali-process the composite fiber in which the other fiber was compounded.

Conventional rayon fibers such as viscose rayon, cupraammonium rayon, Schömberg rayon, high-strength rayon, and fortic acid have a cellulose II crystal structure in the crystal region (see PH Hermans, Makromolecules, Chem., Vol. 6, pp). 25-29 and J. Dyer and GC Daul, Handbook of Fiber Science and Technology: Volume IV (Edited by M. Lewin and EM Pearce; Fiber Chemistry, p968, Marcel Dekker 1985), the rayon fibers of the present invention It has both Ⅱ and cellulose IV crystal structures.

Conventionally, in order to make the cellulose IV crystal structure, cellulose II and III crystals were treated at about 250 to 290 ° C. in glycerin (Japanese Institute of Textile Machinery and Fibers, Textile Engineering (II): Fabrication Structure and Physical Properties, p219, Japanese Textile Machinery Society, 1990.

Unlike the conventional method described above, according to the present invention, in the saponification process of cellulose acetate fibers, the molecular chains of cellulose acetate fibers, which are mostly amorphous regions, are converted into cellulose molecular chains, and at the same time, the molecular chains of the cellulose acetate fibers are folded and packed. Crystallization occurs, the birefringence, which indicates the degree of orientation of the molecular chain, decreases and the number of crystal regions increases, resulting in a complex form of the cellulose II crystal structure and the cellulose IV crystal structure.

In the present invention, saponification of cellulose acetate fibers can be performed by strong alkali treatment alone or strong alkali and weak alkali by copper bath treatment or bathing treatment. In the saponification process of cellulose acetate, quaternary ammonium, phosphonium, etc., which are saponification promoters, may be added in addition to the alkali.

Examples of alkali compounds that may be preferably used in the saponification process include alkali metal hydroxides such as sodium hydroxide, alkaline earth metal hydroxides such as calcium hydroxide, alkali metal carbonates such as sodium carbonate, and the like. These alkali compounds may be used alone or in combination with a saponification promoter.

Commercially available examples of saponification promoters include NEORATE NCB, a phosphonium-based saponification promoter; KF NEORATE NA-40, a quaternary ammonium-based saponification promoter, DK-1125 [DYK-1125: one-sided product], DX- 10 yen [DXY-10N: one-sided product], casein PES, casein PEL, casein PEF [Sungsung Chemicals], SNOGEN PDS (Daeyoung Chemical) Etc. can be mentioned.

In the saponification process, it is preferable that the alkali is made into an aqueous solution so as to be 10 to 60 wt% with respect to the cellulose acetate as a raw material, and then immersed the cellulose acetate as a raw material, preferably at 80 ° C or higher, more preferably at 80 ° C to 130 ^° C. Do. Although not particularly limited, it is suitable to perform saponification once or twice in an aqueous alkali solution for 1 to 60 minutes.

According to the present invention, a method of manufacturing rayon fibers having both cellulose II and cellulose IV crystal structures has an advantage in that the manufacturing process is simple and the manufacturing cost is low. In addition, by cellulizing cellulose acetate, the environmental burden caused by the use of high concentration alkali, carbon disulfide and sulfuric acid, such as viscose rayon is high, high cost, and does not go through complicated process, and uses various cellulose acetate fibers or textile products Rayon has the advantage of producing a friendly and simple manufacturing method.

Rayon fibers of the Y-shaped cross-section produced by the present invention has an increased cutting strength, equal or increased cutting elongation, reduced birefringence, increased crystallinity, specific gravity and moisture content compared to cellulose acetate fibers as a raw material. Is higher and has a Y-shaped cross section that was not seen in conventional rayon.

In the saponification process of the present invention, the molecular chains of cellulose acetate fibers, which are mostly amorphous regions, are transformed into cellulose molecular chains, and at the same time, the molecular chains are crystallized by rearrangement of folding and packing, and the degree of orientation of the molecular chains is increased. As the birefringence shown decreases and the crystal region increases, the fibers of the present invention exhibit a crystallinity of 14 to 34% and a birefringence of 0.012 to 0.024. Due to this, the rayon fiber of the present invention has a specific gravity that increases from 1.32 (cellulose diacetate) to 1.48 to 1.51 gm / cm ^{3, which} is similar to the specific gravity of viscose rayon. In addition, the cutting strength and elongation of the cellulose acetate fibers as raw materials are 1.2 to 1.4 gf / de, 20 to 40% elongation, whereas the rayon fibers of the present invention have a strength of 1.2 to 2.5 gf / de and 20 to 50% elongation. Indicates. In other words, the rayon fiber of the present invention exhibits strength and elongation similar to those of conventional viscose rayon.

Accordingly, the rayon of the present invention may be applied to the same use because mechanical properties such as strength and elongation, physical properties such as specific gravity, crystallinity, and orientation, moisture content, and solubility in solvent are similar to those of conventional viscose rayon.

In addition, the rayon fiber of the present invention is dyed with a dye for cellulose fibers, such as direct dyes, reactive dyes, bat dyes, naphthol dyes, sulfur dyes, and shows excellent dyeing properties, such as mercerized cotton or viscose rayon. In addition, having a Y-shaped cross section has an excellent shari feeling.

The rayon fiber of the present invention is insoluble in dichloromethane, dimethylformamide, dimethyl sulfoxide and acetone, which are the organic solvents of acetate, and is treated with N-methylmorpholine-N-oxide, lithium chloride / dimethylacetamide, which is an organic solvent of cellulose, and the like. It has the property of dissolving in docsene.

Features and other advantages of the present invention as described above will become more apparent from the following examples. However, the present invention is not limited to the following examples.

In the following examples, the loss ratio of cellulose acetate is measured by the following method.

* Reduction rate: The weight change of the sample before and after alkali treatment was measured and obtained by the following equation.

Deacetylation: Deacetylation was confirmed by infrared spectroscopy using an infrared spectrometer (MAGNA 750, Nicolet, USA). At this time, the degree of deacetylation was confirmed that the acetyl group carbonyl band appearing near 1740cm ^-1 disappears.

* Cut strength and elongation of fiber: Measured by pulling at sample length 50mm and tensile speed 200m / min using universal testing machine (Universal Testing Mashin: ZWICK 1425, Germany).

* Moisture content of the fiber: measured by KS-K 0220 oven method.

* Dyeing: After dyeing CI Direct Blue 200 (Kayarus Supra Blue 4BL, Japan Chemical Co., Ltd.) at 90% for 30 minutes at 1% owf concentration, soaping and rinsing at 70 ℃ Staining was completed. The resulting dye was measured using a spectrophotometer (Color-Eye 7000A, Macbeth, USA) to measure the reflectance (R: Reflectance) and substituted into the equation K / S = (1-R) ² / 2R to give a K / S value. Was obtained and the dyeability was compared and evaluated using this value.

[Examples 1 to 5]

After scouring and drying the plain woven fabric (inclined 75d / 20f, weft 120d / 33f, and stomach density 75 / inch) of Y-shaped cross-section cellulose diacetate fiber with acetyl substitution degree 2.55 (56.9% superoxide), 31.3 to 40 wt% of caustic soda was added to the diacetate fiber. The refined and dried diacetate fibers were placed in a liquid dyeing machine, and then heated at 30 ° C. to 2 ° C./min, treated at 98 ° C. for 30 minutes, cooled to 30 ° C. at 2 ° C./min, and drained. Water was added at room temperature and washed with water to remove residual alkali and dried the fibers. Through this saponification process, a fiber having a loss ratio of 34-40% relative to the initial diacetate fiber weight was obtained.

Infrared spectroscopic analysis of raw fiber and fiber reduced by saponification showed that diacetate fiber showed a large carbonyl band of acetyl group near 1740cm ^-1 , whereas 34% reduction of rayon fiber When the carbonyl band was greatly reduced and 40% of the weight loss occurred, the carbonyl band disappeared completely, and the hydroxy stretching of 3400 cm ⁻¹ increased with the reduction rate, indicating that all acetyl groups were substituted with hydroxy groups.

The physical property measurement results of the fibers obtained in the above examples are shown in Table 1. As can be seen from the results of Table 1, the sample (control) without weight loss treatment exhibited intrinsic physical properties of cellulose diacetate, whereas the reduction ratio of 33.6% of acetyl substitution degree among all hydroxy groups was 15%. From the Example 1 sample to the fully deacetylated Example 5 sample, the cutting strength was significantly increased, and the specific gravity, moisture content, and dyeability to the direct dye were similar to viscose rayon (75 / f / 24d manufactured by Cherkassy, Ukraine).

division Process conditions Fiber Properties NaOH Usage (wt%) Reduction rate (%) De Cutting strength (gf / de) Elongation at break (%) Specific gravity (gm / cm 3) Moisture content (%) K / S value Example 1 31.3 33.6 54.0 1.25 30.2 1.4712 10.5 9.32 Example 2 32.5 35.2 53.2 1.28 33.5 1.4941 10.9 10.42 Example 3 34.8 37.6 52.5 1.30 36.2 1.4949 11.2 11.50 Example 4 36.5 39.2 52.7 1.40 36.1 1.4951 12.1 12.20 Example 5 40.0 40.0 52.5 1.50 36.7 1.4953 12.5 12.30 Control 0 0 75.0 0.68 35.6 1.3100 6.5 0.06

[Examples 6 to 8]

Y-shaped single-sided cellulose diacetate fiber (75d / 24f) and polyester SD 75d / 36f twisted yarn of substitution degree 2.55 (56.9% superoxidation degree) were combined with air entanglement and then twisted to 1,000 T / M by a conventional method. Double Twill fabrics with one composite yarn as warp yarn and Y-shaped single-sided cellulose diacetate fibers (150d / 33f, 1,000 T / M) as weft yarns (inclined density 136 / inch, weft density 103 / inch) Was refined and dried by a conventional method. 10-30 wt% of soda recovery solution based on the diacetate fiber weight was added to the liquid dyeing machine, and the scouring-dried fabric was added thereto, and the temperature was increased to 30 ° C. to 98 ° C. at 2 ° C./min. After treatment at 98 ° C. for 30 minutes, the mixture was cooled to 2 ° C./min up to 30 ° C., drained, poured fresh water, and washed with water to complete the first weight loss. A portion of the washed fibers was taken and placed in a dryer at 120 ° C. and weighed. Subsequently, water was added to the liquid dyeing machine, and 30 to 37 wt% of caustic soda was added to the soda-circuit-reduced fiber and treated at 98 ° C. for 30 minutes to reduce the secondary weight. It was. In order to calculate the loss ratio of the acetate portion, the dry weight of the fabric was measured before and after the treatment and dissolved in acetone to determine the loss ratio of the acetate portion by measuring the dry weight of the remaining polyester. The measurement results are shown in Table 2.

Example 9

After refining and drying the double twill fabric of Example 6 in a conventional method, 40% by weight of caustic soda relative to the weight of diacetate fiber was added to the liquid dyeing machine, followed by weight loss at 98 ° C. for 30 minutes, followed by water washing at room temperature to remove residual alkali. Removed and dried. In order to calculate the loss ratio of the acetate portion, the dry weight of the fabric was measured before and after the treatment and dissolved in acetone to determine the loss ratio of the acetate portion by measuring the dry weight of the remaining polyester. The measurement results are shown in Table 2.

division Safflower condition Physical Properties of Y-Type Rayon Fibers 1st safflower (soda ash) Secondary saponification (NaOH) Reduction rate (%) De Cutting strength (gf / de) Elongation at break (%) Specific gravity (gm / cm 3) K / S value Example 6 10wt% 37wt% 39.7 106.5 1.49 36.7 1.4955 12.7 Example 7 20wt% 34wt% 39.5 105.1 1.49 36.9 1.4955 13.4 Example 8 30wt% 30wt% 39.3 104.8 1.50 37.1 1.4979 13.6 Example 9 - 40wt% 40.0 106.2 1.48 36.7 1.4952 15.0

From the results of Table 2, compared to the sample of Example 9 treated with caustic soda alone, the samples of Examples 6 to 8 subjected to primary saponification with caustic soda after the saponification with caustic soda increased the cutting strength and the amount of primary soda ash added. As the diameter increased, the breaking strength of the fiber increased. In addition, the cutting strength, elongation at break, specific gravity, and dyeability to direct dyes were similar to those of viscose rayon.

As described above, the Y-type cross-sectional rayon fiber of the present invention has the same properties as mechanical properties such as strength and elongation, physical properties such as specific gravity, crystallinity and orientation, moisture content and solubility in solvent are similar to those of conventional viscose rayon. It can be applied and also has advantages such as having an excellent shari feeling compared to existing rayon fibers.

1 is an electron micrograph of a Y-type cross-section rayon fiber prepared by one embodiment of the manufacturing method of the present invention

Claims (6)

At least 75% of the total acetyl groups of the cellulose acetate fibers were hydrolyzed by alkali treatment of the fibers or the fibrous products having a degree of substitution of 2.0 to 2.75 (45 to 59.5% of superoxide) and at least part of the cellulose acetate fibers having a Y-shaped cross section. A method for producing a Y-type cross-section rayon fiber, comprising the step of converting into a rayon fiber of a Y-type cross section in which a cellulose group and a cellulose IV crystal structure are mixed with a hydroxy group. The method for producing a Y-type cross-section rayon fiber according to claim 1, wherein the alkali treatment is performed by strong alkali treatment alone, copper bath treatment of strong alkali and weak alkali, or bathing treatment of strong alkali and weak alkali. The method for producing a Y-type cross-section rayon fiber according to claim 1, wherein quaternary ammonium salt and / or phosphonium salt are added to the alkali treatment as a saponification promoter. The knitted fabric of claim 1, wherein the fiber or textile product containing at least a portion of the cellulose acetate fibers having a Y-shaped cross section comprises cellulose acetate fibers of a Y-shaped cross section; Cellulose acetate fibers of Y-shaped cross section alone; Or the cellulose acetate fiber of the Y-type cross section is a composite fiber in which other fibers are composited. It is prepared by the method according to any one of claims 1 to 4, characterized in that the cut strength is 2.5gf / de or less, the cut elongation is 20% or more, the cellulose II crystal structure and cellulose IV crystal structure is mixed Y-type single-sided rayon fiber. The Y-type cross-section rayon fiber according to claim 5, wherein the specific gravity has a range of 1.45 to 1.51 gm / cm ³ .