JPS61138712A - Production of acrylic yarn having improved durability - Google Patents

Abstract

PURPOSE:To obtain the titled yarn useful as blankets, etc., having improved compression recovery ration, by dissolving an acrylonitrile polymer in dimethyl sulfoxide to form a dope, spinning it into a coagulating bath under a specific condition, pulling it up, and drawing it. CONSTITUTION:An acrylonitrile polymer containing >=50wt% acrylonitrile is dissolved in dimethyl sulfoxide to give a dope. Then, the dope is spun into a coagulating bath consisting of a solvent such as a rhodanide, dime thylformamide, etc. and a coagulating agent such as water, methanol, etc., set in a concentration range unable to from a skin layer, and the yarn coagulat ed at >=5 spinning draft within <=60 seconds retention time of the coagulating bath is pulled up. Then, the yarn is drawn at >=5 times by a drawing bath consisting of a solvent and a coagulating agent, set in a concentration range unable to form a skin layer, to give the aimed acrylic yarn.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for producing highly durable acrylic *mO composed of an acrylic 02) IJ polymer or an acrylonitrile copolymer. .

<Prior Art> Acrylic fibers are characterized by a wide variety of manufacturing methods. This is because the raw material polymer is not only a ratio component but also acrylamide, acrylic acid, sodium acrylate,
Contains copolymerized components such as styrene, sodium sulfonate, acrylic modified methyl, vinyl acetate, vinyl chloride, vinyl chloride, etc., and the solvent for dissolving the polymer is an inorganic solvent such as rhodan salt aqueous solution, zinc chloride aqueous solution, nitric acid, etc. , the presence of multiple organic solvents such as trimethylformamide, trimethylacetamide, dimethyl sulfoxide, etc.;
This is because in the wet spinning method, there are many types of coagulants, both aqueous and non-aqueous.

In the normal wet spinning method, for industrial reasons such as spinnability and productivity, the spinning dough is rapidly coagulated in a coagulation bath and g! Generally, the composition of the coagulation bath is set so as to provide conditions for atomization. However, when *= is obtained using a coagulation bath with such a composition, the coagulation force is strong, and a dense and hard skin layer with a thickness of about 0.1 to iμm and internal maid are formed on the surface of the fiber. be done.

Such a skin layer is not only a hindrance to the diffusion of dye during dyeing, but also a cause of deterioration of physical properties such as flexibility of the fiber. Furthermore, the presence of maid often causes defects in physical properties such as devitrification, decreased color development, and lack of flexibility. The appearance of this skin layer and maid also disappears through post-processing such as stretching and heat treatment.

Acrylic fibers are dyed with cationic dyes and have excellent durability and vivid coloring properties, and are used in interior fields such as curtains and carpets, bedding fields such as blankets, and clothing such as knits and glossy textiles. Widely used in the field.

<Problems to be Solved by the Invention> With the recent diversification of consumer needs, highly durable acrylic fibers have come to be required.

In view of the current situation, the inventors of the present invention have made extensive studies and have found that - by essentially eliminating the skin layer and voids that occur in one process and forming continuous fibrils, the present inventors have found that: We succeeded in obtaining acrylic fibers with excellent durability.

<Means for Solving the Problems> That is, the present invention provides a dope obtained by dissolving the polymer in dimethyl sulfoxide when wet spinning an acrylonitrile polymer containing at least 50 g of acrylonitrile. , the fibers are spun into a coagulation bath consisting of a solvent and a coagulant set at a concentration range that makes it impossible to form a skin layer, and the fibers that have been coagulated at a spinning draft of 5 or more and within 60 seconds of residence time in the coagulation bath are pulled up, and then the concentration is set to a concentration that makes it impossible to form a skin layer. The present invention provides a method for producing acrylic fibers with excellent durability, which is characterized by stretching 5 times or more in a stretching bath consisting of a solvent and a coagulant set within a certain range.

In the method of the present invention, an acrylonitrile-based polymer containing at least 50 parts by weight of acrylonitrile is dissolved in dimethyl sulfoxide. Although the dissolution may be carried out at room temperature, it may be heated to a temperature range of 1 to 90° C. in order to improve IJ solubility. If the temperature is too low, the solubility decreases, making it impossible to obtain a dope that can be used for spinning. Moreover, if it is too high, the polymer will be colored and deteriorated. A suitable spinning dope is 10
Contains ~4 olLt% acrylonitrile polymer.

Next, it is made into fibers by this B-F spinning method. Dogue is spun into a coagulation bath consisting of a coagulant and a solvent that dissolves the acrylonitrile polymer at a concentration range that does not allow the formation of a skin layer. Conventionally, the solvents used here include concentrated aqueous solutions of inorganic salts such as rhodan salt, lithium bromide, zinc chloride, and aluminum perchlorate, as inorganic solvents;
Concentrated aqueous solutions of inorganic acids such as nitric acid, sulfuric acid, and perchloric acid; organic solvents such as amide compounds such as trimethylformamide and trimethylacetamide; nitrile compounds; sulfone and sulfoxide compounds such as dimethyl sulfoxide; thiocyanate compounds; Type compounds, amine compounds, phosphorus compounds, carbonate compounds, and mixtures thereof are used.

In addition, coagulants include water, methanol, ethanol,
Chrononol, ethanol, acetone, -acetic acid, ethylene glycol, glycerin, carbon tetrachloride, xylene,
Benzene, chloroform, carbon tetrachloride, ethyl acetate, etc. are known. The composition of the coagulation bath used industrially is generally a combination of the above-mentioned solvent and water, and from the viewpoint of productivity such as one recovery, the solvent in the coagulation bath and the solvent in Dogue are usually the same. used.

Conventionally, the concentration of the solvent in these coagulation baths is usually in a concentration range such that a skin layer is formed. This means that when considering industrial productivity,
This is because conditions are selected that provide excellent spinning stability and operability. In addition, within the concentration range in which the skin layer cannot be formed, the coagulated fibers meander in the coagulation bath, resulting in the resulting fibers becoming cloudy, losing their transparency, and requiring a long time for coagulation.

Here, the concentration range in which the skin layer cannot be formed can be determined by a scanning electron microscope. Dawg used for fiber formation is spread on a slide glass to a thickness of several μ to IW, and immersed in a coagulation bath prepared from a solvent and a coagulant used for fiber formation. The temperature of the coagulation bath is set at the temperature used for fiber formation. A necessary number of coagulation baths are prepared in which the weight fraction of the solvent in the coagulation bath is varied or the concentration is varied so that the solvent is at intervals of 1 inch. After completion of coagulation, the product is washed with water, methanol, and air-dried to obtain a film-like product.

The surface of this film-like material (the surface not in contact with the slide glass surface) is examined using a scanning electron microscope such as 1 JEOL Ltd.
Observations are made using a manufactured scanning electron microscope at an acceleration voltage of 5 to 15 kV and a magnification of 10,000 times. When observing, 50 to 50
Coat the surface with 0X thickness of Au. This WM
If a skin layer is formed by inspection, 100
At 00x magnification, the surface of the film-like object is smooth;
Only some undulations and deposits were observed. When the skin layer is not formed in the Is degree range, the surface becomes 0. O5Am-pores of several 10 arn and particulate matter of 0.05 to 0.5 μm and 8° are observed. By this method, it is possible to determine the lower limit of the concentration range in which a skin layer cannot be formed. The upper concentration limit can be determined as the non-coagulable concentration of Dawg.

In the coagulation bath used in the method of the present invention, dimethyl sulfoxide is most preferably used as a solvent, and water is most preferably used as a coagulant. The weight fraction of dimethyl sulfoxide in the coagulation bath is set within a concentration range that does not allow skin layer formation,
Usually 70-90]ii is used, preferably 75-8
A concentration range of 9 to 1 is used. The temperature of the coagulation bath is
The temperature is usually set at -5°C to 80°C, preferably 2°C.
A temperature range of 0-60°C is used.

In the method of the present invention, the dope is spun into the aforementioned coagulation bath and then pulled up at a speed such that the spinning draft is 5 or higher. Usually, the spinning draft is set between 5 and 100. Here, the spinning draft is expressed by the following formula.

Spinning draft (pulling roller speed)/()/c'
9-f Discharge linear velocity) The spinning draft is 5.
In the case of unfleshed meat, the fibers may sag or break in the same bath circle,
The fibers become wrapped around the rotating parts, reducing operability, and the resulting fibers become cloudy and lose their transparency.

Furthermore, in the method of the present invention, the residence time of the dough spun into the coagulation bath in the coagulation bath is also an important factor.

If the residence time is too short, coagulation will be incomplete and fiber breakage or adhesion will occur. If the length is too long, the fibers composed of coagulated glue will lack fluidity, and the arrangement of microfibrils and fibrils described below will be insufficient, making it impossible to obtain excellent durability.

A suitable coagulation bath residence time should be set according to the coagulation bath concentration and the denier of the fibers from which the Dogue concentration is obtained, but usually a residence time of 60 seconds or less, preferably a residence time of 0.5 to 30 seconds is used. .

Next, the fibers made up of fluid fibers pulled out of the coagulation bath are stretched five times or more in a drawing bath consisting of a solvent and a coagulant whose concentration is set at a concentration range that does not allow the formation of a skin layer, without going through a water washing process. Ru.

In conventional wet spinning of acrylic fibers, the fibers are pulled up from the coagulation bath, subjected to a water washing process, and then drawn. However, in the method of the present invention, in order to impart excellent durability to the obtained fibers, it is essential that the fibers be drawn in a fluid state without passing through a water washing step. . After passing through the water washing process, the fluidity of the fibers with a glue structure is lacking, similar to or even more so than when the residence time in the coagulation bath is too long, which is a characteristic of the acrylic fibers obtained by the method of the present invention. Excellent durability cannot be obtained. Fibers with suitable durability are drawn in the range of 7 to 30 times. The combination of the solvent and coagulation bath used in the drawing bath is not particularly limited, as long as it is a combination of the solvent and coagulant for the acrylonitrile constituent described above, but it is suitable for industrial productivity and glue fluidity. When considering stability, it is preferable to select a combination of the solvent and water used for Dogue. Further, the temperature of the stretching bath is in the range of 10 to 85°C.

(As the &1 thread becomes lower, the drawability decreases, and if it is too controlled, fiber contact and deterioration are likely to occur.Furthermore, in order to perform drawing efficiently, two or more drawing baths are installed, and multi-step drawing is performed. You may do so.

The higher the stretching ratio in the stretching bath, the more durable and excellent acrylic fibers can be obtained.

Fibers produced within the scope of the present invention are subjected to conventional water washing treatments to remove solvent to less than 0.1%. The washing method may be any of the commonly used methods such as immersion alternating current washing, net washing, and Pi-Zoro washing. The fibers from which the solvent has been removed may be redrawn in hot water or steam to impart more suitable physical properties.

Next, drying is performed to remove moisture contained in the fibers.

Drying may be carried out using a conventionally used drum dryer, cylinder dryer, net dryer, or other publicly available dryer.

The fibers from which water has been removed are then subjected to a heat relaxation treatment.

Thermal relaxation can be carried out in a heated atmosphere such as in pressurized steam, hot air, hot water, or between hot plates.

The excellent durability, which is a characteristic of the fiber obtained by the method of the present invention, does not deteriorate through such water washing, collar stretching, drying, and heat treatment.

The surface structure of the fibers obtained by the method of the present invention was observed using a commercially available scanning electron microscope, for example, JEOL Ltd. 1B11.
When observed using a J8M-3s CF scanning electron microscope at an accelerating voltage of 5 kV and a magnification of 3000 times, the fibers were arranged parallel to the axis direction, with a width of 0.1 to 10 μm and a length of 50 μm.
Fibrillar structures were observed on the flies.

When further observed at 10,000x magnification, the width was 0, 0.
The presence of microfibrillar structures with a thickness of 5 to 0.3 am and a length of 0.5 to 10 am was confirmed. It has become clear that the fibrillar structure is constituted by an aggregation of these microbibril-like structures.

In conventional acrylic fibers, the presence of such fibrillar structures or microfibrillar structures cannot be confirmed even when observed at the same time, and the presence of wrinkles due to volume constriction that is thought to have been formed during the manufacturing process, or Only streaks caused by evaporation of the solvent are observed. The fibers obtained by the method of the present invention exhibit excellent durability due to the presence of fibrillar structures formed by aggregation of microfibrillar structures. Furthermore, the presence of microfibrillar structures was found to be effective in developing deep color development, as a result of dyeing fibers with cationic dyes and performing visual judgment.

<Effects of the Invention> As described above, the fibers obtained by the method of the present invention have excellent durability and can be used in the interior field such as carpets, sheets, and curtains, in the bedding field such as blankets, and in the clothing field such as knits and soyer cloths. It is effective in expanding applications in the field. When used on carpets, it has excellent durability and compression recovery rate, which is 1.5 to 2 times that of conventional products.

The durability of the fiber of the present invention can be determined by measuring the hook strength and elongation using the fiber tensile test method shown in JIS, Ll 069.
d) can be denoted by xL6(1>).

The fiber of the present invention has a hook strength and elongation product that is 1.5 to 3 times that of conventional products.

<Example> Hereinafter, the method of the present invention will be explained in more detail with reference to Examples.

Example 1 Acrylonitrile 91.5%, methyl acrylate 8%,
A copolymer consisting of 0.5% methallylsulfonate was dissolved in commercially available 100% dimethyl sulfoxide at 50° C. to prepare a spinning dope of '4 in 2013/.

Next, this stock solution was heated to 30°C with a pore diameter of 0.2 m and a pore number of 100.
The sample was extruded into the coagulation bath using a nozzle of 1 m/win at a linear discharge speed of 1 m/win, and taken out from the coagulation bath at a winding speed of 12 m/n+in. At this time, the residence time of the coagulated fibers in the coagulation bath was 14 seconds. Further, the coagulation bath was composed of an 80% by weight dimethyl sulfoxide water bath solution, and the temperature was 25°C. A bath composed of an 80% by weight dimethyl sulfoxide 9 aqueous solution was stretched 8 times in a stretching bath at 80°C. After the stretched fibers were washed with water, they were thoroughly dried in hot air at 130°C and subjected to a thermal relaxation treatment in steam at 120°C. The hooking strength and elongation product of this fiber (L S
F,) was 231.

As a result of observing the obtained fibers with a scanning electron microscope, it was found that the surface of the fibers had @0.1 to 0.2 μrn and a length of O, S to 3
It was observed that microfibrillar structures of μm size were arranged in the fiber axis direction. In addition, these microfibrillar structures aggregate to have a width of 0.5 to 5 μm and a length of 50 μ+ in the fiber axis direction! Bi-ipryl-like structures of 1-400 μm were observed.

Example 2 91.5% acrylonitrile, 8% methyl acrylate,
A copolymer consisting of 0.5% sodium meta II sulfonate was dissolved in commercially available 100% dimethyl sulfoxide at 50° C., and a 20% by weight spinning stock solution was expanded for 14 hours.

Then, this stock solution was extruded into a coagulation bath using a nozzle with a hole diameter of 0.4 wm and a number of holes of 50 at a discharge linear velocity of in/rnln and taken out from the coagulation bath at a winding speed of 10 m/rnin. At this time, the residence time of the coagulated fibers in the coagulation bath was 11 seconds. The coagulation bath was composed of an 85% by weight dimethyl sulfoxide aqueous solution, and the temperature was 25°C. Subsequently, the film was stretched 10 times in a stretching bath containing an 85% by weight dimethyl sulfoxide aqueous solution at 80°C.

After being dissolved in water, the stretched fibers were thoroughly dried in hot air at 130°C and subjected to thermal relaxation treatment in steam at 120°C.

This fiber had a hook strength elongation product (LSXLE) of 241.

Comparative Example 1 91.5% acrylonitrile, 8% methyl acrylate,
Meta'f Rusuru Nail ◆ A copolymer consisting of 0.5 chloride of sodium phosphate was dissolved in commercially available 100-thinomethyl sulfoxide at 50°C to make a 20% by weight spinning stock solution! I made it.

Next, using a nozzle with a hole diameter of 0.2 m and a number of holes of 100, this stock solution was extruded into the coagulation bath at a discharge linear velocity of 1 m/min, and an attempt was made to take it out at a winding multispeed of 10 n/rnin. However, the fibers were frequently cut and could not be removed. The winding speed was lowered to 2n/rnin and taken out.

The coagulation bath residence time at this time was 80 seconds. Further, the coagulation bath was composed of a 50% by weight dimethyl sulfoxide aqueous solution, and the temperature was 30°C. After washing the extracted fibers with water,
It was stretched 10 times in hot water at 90°C. The fibers that had been stretched were sufficiently dried in hot air at 130°C and subjected to thermal relaxation treatment in steam at 120°C. The hooked strength and elongation product (LSXLK) of this fiber was 121.

Comparative Example 2 91.5% acrylonitrile, 8% methyl acrylate,
A copolymer consisting of 0.5% methallyl sulfonate was dissolved in commercially available 100 tinomethyl sulfoxide at 50 DEG C. to prepare a spinning stock solution of 100 ml.

Next, this stock solution was poured into a hole with a pore diameter of 0.4 m and a hole M 50 O.
Using a nozzle, it was extruded into the coagulation bath at a discharge linear velocity of Im/min, and taken out from the coagulation bath at a winding speed of Iom/min. At this time, the residence time of the coagulated fibers in the coagulation bath was 11 seconds. The coagulation bath was composed of an 80% dimethyl sulfoxide aqueous solution, and the temperature was 25°C. Subsequently, the fibers were thoroughly washed with water and then stretched 10 times in a stretching bath containing an 80% by weight aqueous solution of somethylformamide at a bath temperature of 80'C. The stretched fibers were washed with water, thoroughly dried in hot air at 130°C, and then subjected to a thermal relaxation treatment in steam at 120°C. The obtained fiber was cloudy and could not be used as a product. The hook of this fiber is determined by the strength elongation product (LSXLg) 1tfAll.
It was 01.

Comparative Example 3 In Comparative Example 1, the fibers taken out from the coagulation bath were stretched 10 times in a stretching bath containing an 80% by weight dimethyl sulfoxide aqueous solution at a bath temperature of 80°C, without washing with water. Wash this fiber with water and thoroughly dry it in hot air at 130℃,
Thermal relaxation treatment was performed in steam at 120°C. This fiber had a hook strength elongation product (LSXLE) of 136.

Claims (1)

[Claims] 1. When wet-spinning an acrylonitrile-based polymer containing at least 50% by weight of acrylonitrile, the dope obtained by dissolving the polymer in dimethyl sulfoxide is mixed with a solvent and a coagulant set in a concentration range that does not allow the formation of a skin layer. The fibers are spun into a coagulation bath consisting of a spinning draft of 5 or more and the coagulation bath residence time is 60 seconds or less, and the fibers are pulled up, and then the fibers are spun into a drawing bath consisting of a solvent and a coagulant whose concentration is set at a concentration range that does not allow skin layer formation. A method for producing acrylic fiber with excellent durability, which is characterized by stretching more than twice as much.