JPS6364528B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel composite fiber with excellent thermal stability. More specifically, the present invention relates to a novel composite fiber composed of a cellulose derivative and an acrylonitrile polymer, which has excellent thermal stability and is obtained by phase-separating and dispersing the cellulose derivative into fine fibers. The aim is not only to improve the mechanical properties of the fibers, but also to
An object of the present invention is to provide an acrylic composite fiber that has good thermal stability and excellent dimensional stability during dyeing or ironing. In general, acrylic fibers have a texture similar to that of western wool, and have good abrasion resistance, high photostability, and excellent dyeability, making them extremely useful for clothing, industrial materials, or semi-industrial materials. Although it is a fiber,
Not only in industrial materials, but also in semi-industrial materials and clothing applications, they have had major drawbacks of poor thermal stability as well as tensile strength and elongation. That is, when conventional spun yarns, fabrics, or clothing made from acrylic fibers or mixtures of acrylic fibers and other fibers are subjected to thermal washing, dyeing operations, etc., they undergo thermal deformation and stretch. The weave is distorted, the knitted fabric becomes wavy due to the heating tension during ironing, and the fabric structure is crushed, resulting in shine and discoloration, which significantly reduces the commercial value. Attempts to improve thermal stability include fibers crosslinked with acrylonitrile copolymers copolymerized with crosslinkable monomers, sheath cores made of methacrylonitrile, acrylonitrile copolymers, and polyacrylonitrile polymers. type composite fibers are known. However, these fibers have a major drawback in that dyeability, which is most important for practical fibers such as clothing or interior decoration, is reduced. Attempts have been made to copolymerize this polymer with other nonionizable monomers in an attempt to improve this drawback, but in that case, only acrylic fibers with poor thermal stability were obtained, and it was difficult to use them. Nakatsuta. In view of these drawbacks of acrylic fibers, the present inventors conducted intensive studies on composite fiber systems consisting of a combination of an acrylonitrile polymer and various polymers, and found that the acrylonitrile polymer constituting the composite fiber The present invention significantly improves the drawbacks of conventional acrylic fibers while retaining their excellent characteristics by using a cellulose derivative as a component other than that, and by creating a specific dispersion structure and a specific fiber microstructure. The fiber was discovered and completed. That is, in the present invention, a fiber obtained by spinning and drawing a dope composition consisting of a cellulose derivative, an acrylonitrile polymer, and a solvent that substantially dissolves these simultaneously, under a tension of 0.01 to 0.1 g/d, 100
A fiber heat-treated at a temperature of ℃ or higher and under conditions satisfying the following formula (4), which is substantially made of 3 to 15% by weight of a cellulose derivative and 85 to 97% by weight of an acrylonitrile polymer. It is a fiber formed by phase-separating and dispersing a cellulose derivative into fine fibers, and the crystal orientation angle of the acrylonitrile polymer portion measured by wide-angle X-ray diffraction is 18 to 1.
63°, the ratio of the crystal orientation angle between the cellulose derivative part and the acrylonitrile polymer part satisfies the following formula (1), and the viscoelastic loss tangent (hereinafter abbreviated as tanδ)
In the temperature curve of , the following formula (2) is satisfied and the following formula
Composite fiber with excellent thermal stability expressed by (3) below 10% 0.8≦αCell Der／αPAN≦1.2 (1) tanδmax／(tanδ) _T=60 +(tanδ) _{T= 200} −0.5≦1.45
(2) (However, in formula (1), αcell Der is the crystal orientation angle (°) of the cellulose derivative part, αPAN represents the crystal orientation angle (°) of the acrylonitrile polymer part, and in formula (2), tanδmax is the maximum value of tanδ determined from the tanδ vs. temperature curve measured in the range of 40℃ to 220℃, and (tanδ) _T=60 and (tanδ) _T=200 are the tanδ values at 60℃ and 200℃, respectively. ) Thermoform stability (%) = l-l _O /l _O ×100 (3) (However, in formula (3), l _O is 5000 denier tow,
is the initial length (cm) measured under a load of 0.1 g/d at room temperature, and is the length (cm) of the tow after being immersed in a boiling water bath for 10 minutes under a load of 0.1 g/d. ) (In formula (4), R: heat treatment time (sec), D: total denier of the fibers subjected to treatment, t: treatment tension (g/d), T: treatment temperature (〓)) It is something. The present invention is a fiber consisting essentially of a cellulose derivative and an acrylonitrile-based polymer, in which the cellulose derivative is phase-separated and dispersed into fine fibers, the acrylonitrile-based fiber being measured by wide-angle X-ray diffraction. The crystal orientation angle of the polymer part is 18 to 63°, the ratio of the crystal orientation angle of the cellulose derivative part and the acrylonitrile polymer part satisfies the following formula (1), and Dynamic viscoelastic loss tangent (hereinafter abbreviated as tanδ) measured over a temperature range
However, it is a new composite fiber that satisfies the following formula (2) and has a thermal stability expressed by formula (3) of 10% or less, and its purpose is to fabricate fibers such as woven or knitted fabrics. When used as a product, it has excellent thermal stability, with little loss of shrinkage and elasticity, and no so-called sagging phenomenon, especially in various processes that involve moist heat treatment, such as heat washing, dyeing, ironing, etc.
Moreover, it is an object of the present invention to provide a composite fiber having excellent mechanical fiber performance such as tensile elongation. Conventionally, it has been known that a dope in which a cellulose derivative and an acrylonitrile polymer are dissolved in a solvent and that such a dope undergoes phase separation, and that a cellulose derivative is phase separated and dispersed in an acrylonitrile polymer from such a dope. Fibers that do this are already known. For example, the journal by Mr.
Of Polymer Science, Vol. 20, p. 155 (1966) In Japanese Patent Publication No. 37-2986, a concentrated aqueous solution of inorganic salts or
Publication No. 14029 describes that fibers can be produced from a dope prepared by dissolving cellulose acetate and an acrylonitrile polymer in dimethyl sulfoxide. Furthermore, Japanese Patent Publication No. 33-4023 discloses a fiber made of cyanoethyl cellulose as a cellulose derivative and an acrylonitrile polymer. However, although the fibers obtained by such known techniques are effective in dyeing with cellulose dyes or improving hygroscopicity, they do not have the thermal stability that is the main objective of the present inventors. There is no disclosure of the fact or idea that the fibers of the present invention can be achieved only by forming the fibers into a specific dispersed composite fiber structure with a cellulose derivative and an acrylonitrile polymer and a specific microstructure. However, it must be understood that the fibers are fundamentally and essentially completely different from conventionally known fibers made of cellulose derivatives and acrylonitrile polymers. In fact, it goes without saying that the fibers produced by such known techniques do not meet the microstructural requirements of the fibers of the present invention.
Regarding thermal stability, it does not improve that of conventional acrylic fibers, and in some cases, it actually causes a decrease in thermal stability. That is, the characteristics of the fiber of the present invention are that the cellulose derivative forming the composite fiber is uniformly dispersed in the fiber in the form of phase-separated fine fibers, and the highly oriented acrylonitrile polymer is used to form the acrylic fiber. By creating a unique microstructure using a cellulose derivative as a filler, which has an orientation suitable for the orientation of the acrylonitrile polymer as a matrix, while retaining the characteristics of
The key point is that thermal stability is imparted, which cannot be achieved simply by mixing a cellulose derivative and an acrylonitrile polymer. In the fiber of the present invention, it is desirable that the cellulose derivative content is substantially 3 to 15% by weight. If the content of the cellulose derivative is less than 3% by weight, the thermal stability which is the object of the present invention cannot be sufficiently exhibited, and in some cases, phase-separated composite fibers may not be obtained. On the other hand, if the content is 15% by weight or more, the fibers can satisfy the microstructural requirements shown in formulas (1) and (2) and have excellent thermal stability; however, due to the phase separation structure, This is not preferable because the tendency of fibrillation increases greatly, resulting in a major drawback in terms of consumption performance. In the present invention, the cellulose derivative as the filler forming the composite fiber is dispersed in the form of fine fibers, and the crystal orientation angle measured by wide-angle X-ray diffraction method, which will be explained in detail later, is 18° to 63°. Not only is it necessary that the crystal orientation angle ratio between the cellulose derivative portion and the acrylonitrile polymer portion satisfies formula (1). The present inventors, based on the above-mentioned publicly known materials,
Although additional trials were carried out, we were unable to obtain sufficient fibers, and we proceeded with further investigation to get closer to the present invention.
When the crystal orientation angle of the obtained fibers was measured by wide-angle X-ray diffraction, it was found that the crystal orientation angle in the acrylonitrile polymer part was sufficiently small and showed high orientation, but the crystal orientation angle in the cellulose derivative part was was extremely large and exhibited low orientation, making it impossible to obtain fibers satisfying the formula (1) of the present invention. On the other hand, in the fiber of the present invention, the crystal orientation angle of the acrylonitrile polymer part is sufficiently small and has high orientation, and the crystal orientation angle of the cellulose derivative part is similarly small and shows high orientation. The fibers are completely different from conventionally known fibers in the ratio of crystal orientation angles between the cellulose derivative portion and the acrylonitrile polymer portion, resulting in improved mechanical properties. Although the mechanism by which the reinforcing effect on the fiber microstructure that exhibits such a remarkable effect cannot be left out of the realm of speculation, it is at least possible that the stress applied in the direction of the fiber axis or in the direction perpendicular to the fiber axis acts as a filler in the matrix. This is thought to be due to concentration and relaxation in the fine fibrous filler of the cellulose derivative, which is expected to have higher orientation and superior strength and elongation properties and dimensional stability than the acrylonitrile-based polymer. On the other hand, the fine fibers of cellulose derivative as a filler only show low orientation.
If strength and elongation characteristics or dimensional stability are considered to be poor, the filler is likely to be easily cut or elongated due to stress concentration, which will eventually reduce the mechanical properties of the fiber. Furthermore, in the fiber of the present invention, the temperature range is 40℃~
It is important for the dynamic viscoelastic loss tangent measured at 220°C to satisfy equation (2) in order to provide thermal stability. According to the present inventors, any conventional acrylic fiber obtained from an organic solvent system, an inorganic acid solvent system, or an inorganic salt water solvent system has a tan δ of 110 °C to 220 °C measured in the range of 40 °C to 220 °C. 1 around 130℃
It had two tanδ maxima. Furthermore, as mentioned above, the same applies to conventionally known composite fibers made of cellulose derivatives and acrylonitrile polymers.
When we measured tanδ, we found only one maximum near 110℃, which is comparable to that of ordinary acrylic fibers.
It was no different from tanδ. On the other hand, the tan δ of the fiber of the present invention is, for example, as shown in Figure 1, two tan δ
Give a temperature curve of tan δ that shows a maximum, or even if it does not have two maximums, satisfies equation (2),
This is completely different from conventional acrylic fibers and conventional composite fibers made of cellulose derivatives and acrylonitrile polymers. The present inventors repeatedly investigated in detail the temperature characteristics of tan δ and thermal stability of these fibers, and found an extremely close correlation. In other words, the ease of movement of the polymer molecules forming the fibers is 1
tanδ, which can be considered as one measure, is expressed in the above temperature range.
In the range that does not satisfy (2), that is, the range of 1.45 or more,
The deformation under heat load is extremely large, and it is not possible to obtain thermal stability of 10% or less, which is sufficient for the purpose of the present invention. In the present invention, it is preferable that the cellulose derivative as the filler forming the composite fiber is dispersed in the form of fine fibers, and if it exists in the form of extremely coarse particles or non-uniform distribution, the composite effect will be A sufficient effect of improving mechanical properties and thermal stability was not observed, and as shown in the attached optical micrograph of the cross section of the fiber, it is preferable that the fiber be dispersed almost uniformly over the entire cross section. As long as the effect is not impaired, for example, a concentric or eccentric sheath-core type, or distribution such as concentration inside the periphery of the fiber side is also allowed. Since it is impossible with current technology to directly extract the fine fibrous material made of cellulose derivatives distributed in the composite fiber and measure its shape, indirect measurement using an optical or electron microscope is required. Although it is not possible to clearly define the shape, it is generally preferable that the diameter of the fine fibrous material is 1/10 or less of the total composite fiber diameter, preferably 1 μ or less. Also, the ratio of length and diameter of fine fibrous material (length/diameter)
should be at least 20 or higher. As described above, the fibers of the present invention are made of a cellulose derivative and an acrylonitrile polymer, and by having a specific dispersion structure and a specific fiber microstructure, the fibers of the present invention have a texture similar to the wool of conventional acrylic fibers.
Not only does it have characteristics such as high photostability and dyeability, but it also has sufficient mechanical properties, as well as excellent thermal morphological stability, especially dimensional stability under moist heat. The fibers can be used for high-quality textiles such as women's clothing and men's clothing, or for industrial materials, which have traditionally been difficult to achieve with acrylic fibers. The cellulose derivative useful for the fiber of the present invention preferably has a structure represented by the following formula, In the formula, R is acetyl, propioyl, butyryl, stearoyl, acid phthaloyl, alkyl having 1 to 5 carbon atoms, cyanomethyl, cyanoethyl, hydroxymethyl, hydroxyethyl, hydroxypropyl, carboxymethyl and its sodium salt, carboxyethyl and its sodium It represents a group selected from the group consisting of salt, sodium sulfate, and nitro, and O to 4 of R in the two glucose units represented by formula (1) may be hydrogen. Specifically, cellulose acetate, methylcellulose, ethylcellulose, cyanoethylcellulose, methylcyanoethylcellulose, hydroxymethylcellulose, cyanoethylhydroxymethylcellulose, hydroxyethylcellulose, sodium carboxymethylcellulose, sodium carboxyethylcellulose, sodium methylcarboxymethylcellulose, sodium cyanoethylcarboxymethylcellulose, etc. Particularly preferred are cellulose acetate, cyanoethylcellulose, and methylcellulose.
Commercially available products may be used as they are, or those produced and purified by appropriate means may be used. The average degree of substitution (DS) of anhydroglucose units in the cellulose derivative used in the fiber of the present invention is 1.0.
It may be at least 1.5 to 3.0. The average degree of polymerization (DS) of anhydroglucose units varies somewhat depending on the type of cellulose derivative, but is usually
It is preferably between 50 and 700. In the fiber of the present invention, one type of these cellulose derivatives may be used, or a mixture of two or more types may be used. The acrylonitrile polymer used in the fiber of the present invention is an acrylonitrile polymer or an acrylonitrile copolymer obtained by a conventional polymerization method of 40 mol% or more of acrylonitrile and other copolymerizable vinyl monomers. Any of these may be used, but copolymers are preferred from the viewpoint of the dyeability of the resulting fibers, and those containing 85 mol% or more of acrylonitrile are particularly preferred. Examples of specifically used comonomers include acrylamide, methacrylamide, N-methylacrylamide, and N-methylacrylamide.
-Ethyl methacrylamide, maleimide, allyl alcohol, methallyl alcohol, β-hydroxyethyl methacrylate, methallylamine, β-
Aminoethyl methacrylate, acrylic acid, methacrylic acid, itaconic acid, methyl acrylate, methyl methacrylate, ethyl methacrylate, α
Examples include, but are not limited to, methylacrylonitrile, α-cyanoacrylonitrile, vinyl acetate, vinyl chloride, vinylidene chloride, and styrene. The fibers of the present invention can be manufactured specifically and with good reproducibility through the Examples described later, which can be easily replicated by those skilled in the art. Of course, these examples are merely illustrative of some of the production examples of the present invention, and in general, production is carried out with reference to the examples described later and with the following matters in mind. be able to. In the fiber of the present invention, as mentioned above, it is preferable that the composition ratio of the cellulose derivative is 3 to 15% by weight, and in order to produce the fiber, predetermined amounts of the cellulose derivative and the acrylonitrile polymer are each used. A dope is prepared by dissolving the above in a solvent capable of dissolving both, and a fiber is prepared by a conventional wet spinning, semi-dry semi-wet spinning, or dry spinning method. Examples of solvents that can dissolve the two used in dope preparation include N,N-dimethylformamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and organic solvents, zinc chloride, It may be a concentrated aqueous solution of Rodan salt or the like, or a nitric acid aqueous solution, or even a mixed solvent of two or more kinds. The dope concentration may be 5 to 50% by weight, and within this range, it is preferable to set the viscosity suitable for the spinning method, for example, 500 to 2000 poise. As long as the dope used for producing the fiber of the present invention satisfies the above-mentioned conditions, even if it is an optically isotropic dope, there will be no problem.
In particular, it is preferable to use a dope exhibiting flow birefringence. Flow birefringence means that when a small amount of dope is placed between a slide glass and a cover glass and observed under a microscope under orthogonal polarized dark field in a stationary state, no light is transmitted through it, and when the cover glass is pressed with finger pressure, etc. It refers to the optical property of transmitting light by making a similar observation in a flowing state while applying force and shifting, that is, applying a shearing force. Therefore, it can be distinguished from a dope exhibiting optical isotropy. A filament formed from a dope through a spinneret can be made into a fiber by washing with water, stretching, drying, etc., which are common steps in the normal fiber manufacturing process, but the fiber of the present invention has excellent thermal stability. In order to achieve this, the final step is to apply the following formula under dry heat or moist heat conditions of 100℃ or higher, under a tension of 0.01 to 0.1 g/d.
It is important that the heat treatment is carried out under conditions that satisfy (4), and that the fiber of the present invention has thermal stability of 10% or less and excellent mechanical properties such as tensile strength and elongation. I can do it. (In formula (4), R: heat treatment time (sec), D: total denier of the fibers subjected to treatment, t: treatment tension (g/d), T: treatment temperature (〓)) In this way, The resulting fibers of the present invention may be in any form, such as cotton, tow, monofilament, or multifilament, and in any case, they have a wool-like texture that is characteristic of conventional acrylic fibers. In addition, in order to have good abrasion resistance, high photostability, or excellent dyeability,
Acrylic fibers can be used not only in the field of clothing, where they have traditionally been used, but also in semi-industrial materials or industrial material applications, such as tents, car covers, dryer canvas, etc., but especially in women's clothing and men's clothing. It demonstrates its power when used in the field of high-quality textiles such as clothing. Below, methods for measuring the main parameters used to identify the fibers and measure the physical properties of the present invention will be described in detail. <Fibre physical property measurement method>Denier; Torsion balance MODELTI manufactured by Eiko Sangyo Co., Ltd.
Using this method, the single yarn denier was determined from 10 single yarns of 90 mm. Tensile strength and elongation and modulus Using a UTM-20 tensile testing machine manufactured by Toyo Baldwin Co., Ltd., as a single yarn with a yarn length of 20 mm, the head speed was 20 mm/min and the chart speed was 200 mm/min.
The SS curve was measured under the following conditions and determined by a conventional method. <Thermoform stability> Load is 0.1 on yarn length 180mm, 5000 denier tow
A weight of 500 g was applied so as to give g/d, and the elongation rate was measured after 10 minutes in a boiling water bath. <Method for Measuring Crystal Orientation Angle by Wide-Angle X-ray Diffraction> The crystal orientation angle of fibers can be measured by a conventional method using a photograph or a counter. For example, according to the counter method,
Line generator (RU-ZOOPL), fiber measuring device (FS
-3), carried out using a goniometer (SG-9R) and scintillation counter. For measurement, CuKα (=1.54
Å). The fiber of the present invention is characterized by having strong reflection on the equator line due to the cellulose derivative and acrylonitrile fiber. For example, reflection around 2θ=10° is caused by the cellulose derivative, and reflection around 2θ=17° is caused by the acrylonitrile polymer. The above two reflections are used to measure the orientation angle, and the exact value of 2θ of the reflection used to measure the crystal orientation is determined from the diffraction intensity curve in the equatorial direction of each sample. The crystal orientation angles of the cellulose derivative and the acrylonitrile polymer portion are measured by a conventional method using reflection having a 2θ characteristic to each of them. The X-ray generator operates at 32KV100mA. Attach the fiber sample to the fiber measuring device by aligning the single yarns so that they are parallel to each other. It is appropriate that the thickness of the sample be approximately 2 mm. Set the goniometer to the 2θ value determined by preliminary experiments. X perpendicular to the fiber axes arranged in parallel
Inject the beam (beam perpendicular transmission method), rotate the sample in a plane perpendicular to the beam, and azimuth = -90°~
Scan the +90° range and record the diffraction intensity on recording paper. The scanning speed at this time is = 4°/min, chart speed 1cm/min, time constant
5sec, collimator 2mmφ, receiving pinhole is square 2mm on each side. Furthermore, the diffraction intensity can be measured without continuous scanning.
It may also be measured by step scanning. To determine the crystal orientation angle (crystal orientation angle of the cellulose derivative part; αCell Der, crystal orientation angle of the acrylonitrile polymer part; αPAN) from the obtained diffraction intensity curve, calculate the diffraction intensity obtained at = ±90°. Take the average value and draw a horizontal line to use it as the background. Drop a perpendicular line from the top of the peak to the base line and find the midpoint of its height. Draw a horizontal line through the midpoint. The distance between the intersection of this horizontal line and the diffraction intensity curve is measured, and the value obtained by converting this value into an angle (°) is defined as the orientation angle. From the thus determined crystal orientation angle of the cellulose derivative portion (αCell Der) and the crystal orientation angle of the acrylonitrile polymer portion (αPAN), the ratio of the crystal orientation angles (αCell Der/αPAN) was determined. <Method of Measuring Temperature Curve of Dynamic Viscoelastic Loss Tangent (tan δ)> Tan δ can be measured by a conventional method using, for example, a Leo Vibron Model DDV-C manufactured by Toyo Baldwin Co., Ltd. The sample used for the measurement had fibers arranged so as to have, for example, 600 to 800 deniers (5 to 8 x 10 ^-2 mm ² as yarn cross-sectional area) and a length of about 30 mm. The measurement frequency is
110Hz measurement temperature range is 40℃~220℃, 1.0~1.5
The temperature was raised at a rate of .degree. C./min, measurements were taken at each point at intervals of 3 to 5.degree. C., and tan .delta. was determined by a conventional calculation. The tan δ value at each temperature thus determined was plotted with temperature as the horizontal axis and tan δ as the vertical axis, and each point was connected by a smooth curve to form a tan δ-temperature curve. tanδ max, (tanδ) _T=60 , and (tanδ) _T=200 are the maximum value and 60℃, respectively, from this tanδ-temperature curve.
It was determined by reading the tanδ value at 200°C. The present invention will be explained in more detail below with reference to Examples, in which % means % by weight unless otherwise specified. Example 1 Average degree of polymerization (DP) is 316, average degree of substitution (DS)
33.2 g of cyanoethyl cellulose with a concentration of 2.60 and 298.7 g of an acrylonitrile copolymer with ηinh = 1.34 consisting of acrylonitrile/acrylamide/methyl acrylate = 90/5.5/4.5 (mol%) were mixed into 1000 ml of 70
% nitric acid aqueous solution and stirred and dissolved to create a dope with a concentration of 19%. The solution viscosity of this dope at 0°C is 1960 poise, and microscopic observation reveals that fine island-like phases have been separated. It was found that only this island-like phase transmits light and exhibits flow birefringence. This dope was transferred to a dope tank equipped with a cooling jacket, and after vacuum defoaming while maintaining the dope temperature around 0°C, it was spun at 4.27ml/min, 8.50mm using a spinneret with a hole diameter of 0.08mmφ and 100 holes. The yarn was discharged into a coagulation bath consisting of a 35% nitric acid aqueous solution with a bath length of 1 m at a linear discharge speed of /min, then wound up at a speed of 4 m/min, then washed through a 5 m water bath, and then boiled at a boiling point of 2.5 m. A fiber was obtained by stretching 9.9 times in a water bath. After relaxing and drying in a hot air atmosphere at 70°C, the continuous filament with a total denier of 180 was introduced into a heat-treated SUS tube with a length of 2 m and a diameter of 10 cm, labyrinth seals on both ends, and saturated steam (approx. 1
The heat treatment was carried out while maintaining the temperature at 120° C. while blowing a pressure of 1,000 kg/cm ² G pressure. The processing tension at this time is 5 m/min for the inlet roll speed and approximately 5 m/min for the exit roll speed.
It was maintained at 0.05gd while adjusting to 4.6m/min.
The processing time at this time was approximately 24 seconds. Various characteristic values of this fiber and, for comparison, the characteristic values of a known acrylic fiber made only of an acrylonitrile polymer used in this example are shown in Table 1 as Comparative Example 1. In addition, in Example 1 and Comparative Example 1
The tanδ temperature curves are shown in FIG. 1 and FIG. 2, respectively.

[Table] As is clear from Table 1, the fiber of the present invention is composed of a cellulose derivative that exhibits extremely high orientation and an acrylonitrile polymer, and has a surprisingly excellent thermal stability of 3.3%. This shows that. Furthermore, from a comparison with FIGS. 1 and 2, it is clear that the fiber of the present invention is completely different from that made of conventional acrylonitrile polymers in its tan δ temperature curve. 5
As shown in , it was confirmed that the fibers were completely different from conventionally known phase-separated fibers. Examples 2 and 3 Cyanoethyl cellulose with DP330 and DS2.62,
Acrylonitrile/acrylamide/methyl acrylate/sodium methallylsulfonate = 91.5/
Dopes shown in Table 2 were prepared from an acrylonitrile copolymer of ηinh = 1.16 consisting of 3.5/4.5/0.5 (mol%) and a 67% nitric acid aqueous solution, and spun and stretched (10.5% by mole) in the same manner as in Example 1. ) to obtain fibers.

[Table] The characteristic values of the final fiber obtained by subjecting this drawn fiber to the same heat treatment as in Example 1 are as shown in Table 3, and it was found to have extremely excellent thermal stability. An optical microscope cross-sectional photograph of the final fiber obtained in Example 3 is shown in FIG. 3, and the characteristic of the fiber of the present invention is that cyanoethyl cellulose is uniformly dispersed in the form of fine fibers. observed.

[Table] Example 4 As a spinning dope, 35.3 g of cellulose acetate with DP 180 and DS 2.48 and 317.3 g of an acrylonitrile copolymer consisting of acrylonitrile/methyl acrylate = 92/8 (mol%) were added to 750 ml of a 69% nitric acid aqueous solution.
A dope was prepared by dissolving it in This dope was confirmed to exhibit flow birefringence by microscopic observation under orthogonal polarized dark field. This dope was transferred to a dope tank equipped with a cooling jacket, and after vacuum defoaming while maintaining the dope temperature around 0°C, it was spun at 3.37 cc/min and 2.19 m/min using a spinneret with a hole diameter of 0.14 mmφ and a hole diameter of 100 mm. It was discharged into a coagulation bath consisting of a 33% nitric acid aqueous solution with a bath length of 1 m with a space of 4 mm separated at a discharge linear velocity of . The various characteristic values of this fiber are as shown in Table 4, indicating excellent thermal stability, and furthermore, the tensile strength was extremely high at 5.8 g/d.

[Table] Example 5 48.8 g of cyanoethylcellulose was prepared as a spinning dope from the same cyanoethylcellulose and acrylonitrile copolymer used in Example 1.
and 1634g of acrylonitrile copolymer 439.2g
was dissolved in dimethyl sulfoxide heated to 50°C. The viscosity of the dope was 1180 poise at 50°C, making it an optically isotropic dope. This dope was transferred to a dope tank, and after vacuum degassing, a spinneret with a pore diameter of 0.10 mm and a number of holes of 100 was used, and the bath length was 0.8 mm.
m, the yarn was discharged at a rate of 3.98 cc/min into a 50% dimethyl sulfoxide aqueous solution kept at a bath temperature of 31 to 36°C, and the generated yarn was taken up by the first roll at a speed of 5.5 m/min. Then, it was stretched 2.18 times with a second roll at 12.0 m/min. Thereafter, the fibers were washed through a 5 m water bath and then stretched 3.3 times in a 1.8 m boiling water bath to obtain fibers. Next, this drawn fiber is
Dry in a relaxed state in a hot air dryer at 100℃, roll it up to a length of 1m using a measuring device, make a fiber bundle with a total denier of 23500, and process it with a processing tension of 0.06g/d to 1.41Kg. A weight was lowered to one end, and the fiber was heat-treated with pressurized steam at 110°C for 4 minutes and 30 seconds to obtain a final fiber. The mechanical properties and other properties of this fiber are shown in Table 5, and Figure 4 shows the mechanical properties and other properties of this fiber.
The temperature curve of tanδ is shown. As Comparative Example 2, the characteristic values of the fiber before heat treatment are also listed, and although the comparative example fiber showed sufficient orientation of the acrylonitrile copolymer part, the orientation of the cyanoethyl cellulose part was poor, and The shape stability was also significantly inferior to that of the fiber of the present invention.

[Table] Example 6 Cyanoethylcellulose DP318, DS2.66 27.3
g, 97.5 mol% acrylonitrile, 2 mol% acrylamide, 0.5 mol% sodium methacrylsulfonate.
245.7 g of acrylonitrile copolymer with mol% ηinh = 1.19 was added to a 71% zinc chloride aqueous solution at 60°C.
A dope with a concentration of 14% was prepared by dissolving 1677g of the dope.
The dope is transparent and no phase separation is observed, but
It exhibited flow birefringence. After vacuum degassing, this dope was heated to 60°C, and then a spinneret with a pore diameter of 0.14 mmφ and 100 holes was used.
5mm at discharge linear velocity of 4.86cc/min, 3.16m/min
The yarn was discharged into a coagulation bath consisting of a 3.35% zinc chloride aqueous solution at 4°C with a bath length of 1.3 m across a space of A drawn fiber was obtained by drawing 9 times in a 2.5 m boiling water bath. This drawn fiber was then dried at 80°C in a relaxed state, resulting in a total denier
290 continuous filament using the same equipment as in the example at 125°C, 0.04g/d tension and processing time.
Heat treatment was performed for 12 seconds. The characteristic values of the obtained fibers were as shown in Table 6.

【table】 [Brief explanation of drawings]

1 and 4 are tan δ temperature curves of the fibers of the present invention obtained in Examples 1 and 5, and FIG. It is a temperature curve of tanδ.
FIG. 3 is a cross-sectional photograph (400x magnification) of the fiber of the present invention obtained in Example 3, taken with an optical microscope.

Claims (1)

[Scope of Claims] 1. A fiber obtained by spinning and drawing a dope composition consisting of a cellulose derivative, an acrylonitrile polymer, and a solvent that substantially dissolves them simultaneously under a tension of 0.01 to 0.1 g/d. , at temperatures above 100℃,
The fibers are heat-treated under conditions satisfying the following formula (4), and are substantially composed of cellulose derivatives 3 to 15.
% by weight, and 85 to 97% by weight of an acrylonitrile-based polymer, which is a fiber formed by phase separation and dispersion of a cellulose derivative into fine fibers, which is an acrylonitrile-based polymer measured by wide-angle X-ray diffraction. The crystal orientation angle of the polymer part is 18 to 63°, the ratio of the crystal orientation angles of the cellulose derivative part and the acrylonitrile polymer part satisfies the following formula (1), and the viscoelastic loss tangent (hereinafter abbreviated as tanδ) In the temperature curve of
Composite fiber with excellent thermal stability that satisfies the following formula (2) and has a thermal stability expressed by the following formula (3) of 10% or less 0.8≦αCell Der／αPAN≦1.2 (1) tanδmax／ (tanδ) _T=60 + (tanδ) _T=200 −0.5≦1.45
(2) (However, in formula (1), αcell Der is the crystal orientation angle (°) of the cellulose derivative part, αPAN represents the crystal orientation angle (°) of the acrylonitrile polymer part, and in formula (2), tanδmax is the maximum value of tanδ determined from the tanδ vs. temperature curve measured in the range of 40℃ to 220℃, and (tanδ) _T=60 and (tanδ) _T=200 are respectively
It represents the tanδ value at 60℃ and 200℃. ) Thermoform stability (%) = l-lo/lo x 100 (3) (However, in formula (3), lo is 5000 denier tow and nothing,
It is the initial length (cm) measured under a load of 0.1 g/d at room temperature, and l is the length (cm) of the tow after being immersed in a boiling water bath for 10 minutes under a load of 0.1 g/d. be. ) (However, in formula (4), R: heat treatment time (sec), D: total denier of the fibers subjected to treatment, t: treatment tension (g/d), T: treatment temperature (〓)