JPS63112718A - Production of highly shrinkable dry type acrylic yarn - Google Patents

Abstract

PURPOSE:To obtain the titled acrylic yarn having a soft feeling efficiently, by subjecting a spinning stock solution consisting of an acrylonitrile polymer to dry spinning, primarily drawing under a specific condition, drying, relaxing and further secondarily drawing. CONSTITUTION:An acrylonitrile polymer containing >=85wt% acrylonitrile is dissolved in a solvent such as DMF, etc., to give a spinning stock solution. Then the spinning stock solution is subjected through a nozzle to dry spinning to form undrawn yarn, which is drawn in hot water at >=80 deg.C at 2-4 draw ratio. Further, the drawn yarn is dried at 140-170 deg.C dry-bulb temperature and at 80-90 deg.C wet-bulb temperature, relaxed and shrunk by 10-40%. Then the yarn is secondarily drawn under dry heat at 80-130 deg.C at 1.2-2 draw ratio and, immediately after drawing, is quenched by blowing cold air to give the aimed acrylic yarn.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for efficiently producing acrylic high shrinkage fibers obtained by dry spinning.

[Conventional technology]

To produce acrylic fibers from an acrylonitrile polymer by dry spinning, the acrylonitrile polymer is usually dissolved in a solvent such as dimethyl μformamide, dimethylacetamide, etc., and dry spun as a spinning dope to form an undrawn yarn. , followed by stretching, washing, and drying relaxation are used as the basic process, and when producing shrinkable acrylic fibers, post-stretching is further performed under moist heat.
The target shrinkable acrylic fiber has been obtained.

Each unit process in the above basic process is an important process and greatly affects the characteristics and texture of the target final product, so it is necessary to select the spinning method, assemble the unit process, and its manufacturing conditions. Although this has an important industrial significance, the shrinkage rate of shrinkable acrylic fibers produced by conventional dry spinning methods is limited to about 23 cm.

As a conventional technique, a continuous dry spinning method for highly shrinkable acrylonitrile filaments and fibers is known, for example, as disclosed in Japanese Patent Application Laid-open No. 5
This method is proposed in Japanese Patent No. 9-21713. However, the purpose of this proposal is to provide a method for continuously producing high-shrinkage acrylic fibers by dry spinning. This is a method of manufacturing.

In this method, as indicated in the claims, stretching is carried out at least 100,000 DIX (90,000 total denier lv), and the productivity thereof is low on an industrial scale.

[Problem that the invention seeks to solve]

In the present invention, an acrylonitrile-based polymer is made into fibers using a dry spinning method using a spinning solution containing dimethylformamide, dimethylacetamide, etc. as a solvent, which has good physical properties and texture, and has a shrinkage rate of 28% or more. The purpose of the present invention is to develop a method for industrially manufacturing high-shrinkage dry-processed acrylic fibers with good productivity.

The present inventors have developed an acrylonitrile-based synthetic fiber using a dry spinning method that maintains generally required fiber properties (e.g., strength, elongation, dyeability, white skin, texture, etc.), and also has high shrinkage. The present invention was completed with the aim of finding assembly and manufacturing conditions for a unit process that imparts properties.

[Means for solving problems]

The gist of the present invention is to perform dry spinning using a spinning dope made of an acrylonitrile polymer containing 85% or more of acrylonitrile by weight, and then to draw the spinning solution in hot water at 80°C or higher.
It is characterized by stretching the fibers dried and relaxed at a dry bulb temperature of 140 to 170°C and a wet bulb temperature of 80 to 90°C to t2 to 2 times at 80 to 130°C under dry heat, and immediately cooling the fibers immediately after stretching. The method for producing high-shrinkage dry-processed acrylic fibers allows efficient and industrial production of tows or staves of highly-shrinkable dry-processed acrylic fibers that have generally required fiber properties and a steam shrinkage rate of 28 or more. It is manufactured.

The present invention will be specifically explained below.

The acrylonitrile polymer targeted by the present invention is 85
It is necessary to contain acrylonitrile by weight or more, but it may contain 15% by weight or less of a copolymerizable monomer. If the content of acrylonitrile lv is less than this, it is not preferable in terms of obtaining the fiber properties necessary as a clothing fiber. Examples of copolymerizable monomers include (meth)acrylic acid esters such as methyl acrylic acid and methiμ methacrylate, hyphenyl acetate, styrene, and acrylamide. These copolymerization rates are usually 3
~10 wt. Also for improving dyeability (meta)
Acrylic acid, (meth)allylsulfonic acid, vinylbenzenesulfonic acid and their salts, dimethymu aminoethyl A/
It is also possible to copolymerize (meth)acrylate and vinylpyridine. The copolymerization rate of these monomers is usually 3% by weight or less.

Acrylonitrile polymers can be produced by any conventional methods such as suspension polymerization, solution polymerization, and emulsion polymerization.

The degree of polymerization of the polymer is 0.1 expressed as its specific viscosity (1 gram of polymer CL dissolved in 100 grams of dimethyformamide containing 11 N of Rodan soda and measured at 25°C).
A range of 0.2 is preferred.

The polymer spinning stock solution is prepared by adding the polymer to a common solvent for acrylonitrile polymers, such as dimethylformamide, dimethylacetamide, dimethylformamide, dimethylformamide, etc., so that the polymer concentration ranges from 25 to 40% by weight, preferably 28% by weight. The solution is dissolved to a concentration of ~35% by weight to obtain a spinning dope.

Dry spinning is performed by a conventionally known method. That is, 100
The spinning stock solution at ~150°C is passed through the nozzle at 160~28°C.
Extrusion into air or inert gas heated to 0°C to form an undrawn yarn. The hole diameter of the nozzle μ is preferably α12~Q, 5mm. The amount of residual solvent in the formed undrawn yarn is 1% relative to the polymer.
It is preferable that the weight range is from 0 to 35% by weight. If the amount of residual solvent in the undrawn yarn is less than 10% by weight, fuzz will occur on the take-up roll under the spinning tube, and the passability in the next process, especially the drawability, will decrease, causing trouble in the drawing process. do. On the other hand, the amount of residual solvent in the undrawn yarn was 35
If it exceeds % by weight, adherent fibers will occur within the spinning cylinder, causing trouble in subsequent steps and reducing fiber quality.

The spinning speed of this dry spinning is important in order to obtain high shrinkage of the final product, but on the other hand, when spinnability is also taken into consideration,
-350m/min, preferably 200-3oon/min.

The undrawn yarn spun in this way may be continuously fed to a drawing process, but in order to obtain high productivity,
Once the undrawn yarn is received in a can, the undrawn yarn in the can is
It is concentrated to a total density μ of 0,000 to 3,150,000 and led to the next primary stretching step.

Stretching is carried out 2 to 4 times in hot water, and the temperature of the hot water for stretching is 80° to 100°C, preferably 90°C or higher. In addition, setting the draw ratio within the above range is due to the strength and strength required for the fiber.
It is important to impart elongation and obtain high shrinkage, and the stretching ratio is determined in relation to the spinning speed, pressure, and steam treatment pressure, but is preferably 2.5 to
A range of 5x is good.

The undrawn yarn is washed in hot water at the same time as, or before and after the above-mentioned drawing treatment. The temperature of the hot water used for washing is preferably 80 to 100°C.

The amount of solvent remaining in the fibers after washing is usually less than 2 times the weight, and then drying and relaxation treatments are performed.

Drying and relaxation are performed simultaneously in a moist state under no tension, that is, in heated, humid air at a dry bulb temperature of 140 to 170°C and a wet bulb temperature of 80 to 90°C. As a result, the fiber bundle typically shrinks by 10 to 40 fi. The dry bulb temperature and wet bulb temperature of this heated humid air are related to the shrinkage rate of the fibers. That is, the shrinkage rate of the fiber increases in the direction of increasing temperature, and decreases in the direction of decreasing temperature. Therefore, considering only the shrinkage rate of the fibers, the direction of high temperature is preferable. However, since the white skin of the fibers decreases at higher temperatures, taking these two points into consideration, the upper limit of the dry bulb temperature is preferably 170°C.

Next, this fiber bundle is subjected to a dry heat drawing treatment which is a secondary drawing of 1.2 to 2 times under dry heat. The processing speed in this case is 10G
- Can be processed at 300 m/min.

In the present invention, it is necessary to rapidly cool the fiber bundle immediately after this dry heat drawing treatment. The rapid cooling can be carried out using any means such as blowing cold air at around 25° C. or passing through a cooling rod μ.

The dry strength of the fiber obtained by the above-mentioned manufacturing method is 2 to 5
g/d, dry elongation of 15 to 40 inches, good dyeability, soft texture, and shrinkage rate of 28 inches or more.

The shrinkage rate of the final fiber may also change depending on the spinning speed, drawing ratio, drying, relaxation temperature, etc., but the extent of this change is small and depends on the dry heat drawing conditions of the secondary drawing, i.e. the dry heat drawing temperature, the dry heat drawing It mostly depends on the combination of magnifications. The reason why the dry heat drawing temperature is specified as 80 to 130°C is that at a low temperature below 80°C, the elongation of the fiber bundle is insufficient and fiber breakage is likely to occur during drawing, and when it exceeds 130°C, the final fiber This is because, in addition to a decrease in shrinkage rate, there are also disadvantages in that dyeability deteriorates. The stretching ratio is preferably 1.2 to 2 times. 2
If it exceeds 1.2 times, stretching breakage occurs frequently, and if it is less than 1.2 times, the shrinkage rate stops at about 2O4 because the stretching strain is small. In addition, by rapidly cooling the fiber bundle after dry heat drawing, which is the secondary drawing, the heat necessary for drawing is maintained even after drawing, resulting in a kind of heat-fixing effect, which corrects the strain of the fibers and suppresses the shrinkage rate. It is essential to prevent this and obtain high shrinkage of 28% or more.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to Examples. In addition,
In the examples, parts mean parts by weight, and the fiber shrinkage rate was measured by the following method.

Make a knot at both ends of the fiber end 1.5 fi, hang it on a length measuring device, apply a load of 1.259 per 100 dpf to the lower end knot, and measure the length between the upper end knot and the lower end knot. and AQll. Next, remove the fiber bundle from the length measuring device, put it in a steamer in a free state, and heat it for 5 kll.
/cm" of steam is blown into the steamer and treated at normal pressure for 3 minutes. The steam-treated fiber bundle is then cooled with water and then run on a length measuring device again to obtain a length of 1.259 per 100 dpf.
With the load applied, the length between the upper end knot and the lower end knot is measured and defined as BcIn, and the shrinkage rate is determined using the following formula.

Comparative Example In a polymerization pot equipped with a stirrer, 955 parts of acrylonitrile, 6 parts of methi/I acrylate, 0.5 part of sodium metaallylsulfonate, 400 parts of water, and ammonium persulfate Q
, 55 parts of sodium bisulfite, 44 parts of sodium bisulfite, and sulfuric acid were continuously supplied to maintain pu at 50, and polymerization was carried out at a temperature of 55°C. The obtained polymer was thoroughly washed and then dried.

This polymer was heated to 50° C. with sufficient stirring in dimethyzate/l.
/ dilumamide to obtain a spinning stock solution with a concentration of 30 layers. After heating this stock solution to 130℃, the number of holes was 100.
The yarn was discharged into an inert gas heated to 200 DEG C. through a nozzle μ of 0.0 mm, hole diameter Q, and 15 mm, and taken off at a spinning speed of 200 to 5 aatn/min to obtain an undrawn yarn. This undrawn yarn was bundled to a total density of 1.8 million to 3.6 million μ, then stretched in boiling water to a range of 2 to 3 times, and further washed in boiling water, and the resulting fiber bundle was put under no tension. Dry bulb temperature 110~
It was dried and relaxed in humid air at 150° C. and a wet bulb temperature of 80° C., and then post-stretched by 1.8 times in heated steam at normal pressure.

The spinning speed, stretching ratio, drying,
By changing the relaxation temperature and combining
However, the fiber shrinkage rate was 23% or less in all cases.

Example 1 A spinning stock solution with a concentration of 30% by weight was prepared in the same manner as in the comparative example, and the undrawn yarn obtained by spinning at a spinning speed of 250 to 300 rrL/min was bundled to 1.8 million to 2.7 million daughter μ denier.
After stretching 2 to 55 times in boiling water and washing in boiling water, dry bulb temperature (Tp) 150°C, wet bulb temperature (TV) 8
Dry and relax in humid air at 0℃, then dry heat at 120℃
Immediately after stretching, the fiber bundle was quenched by blowing cold air at about 25°C. The steam shrinkage rate of the obtained fiber was 5 (
It was L5chi.

Within the range of manufacturing conditions mentioned above, the spinning speed, primary draw ratio, 2
The results of changing conditions such as thorn stretching temperature, secondary stretching ratio, presence or absence of rapid cooling, etc. are as shown in Tables 46 to 9 (Example) and I & 10 to 11 (Comparative Examples). The effect of rapid cooling after dry heat stretching is obvious.

〔Effect of the invention〕

The characteristics of the fiber obtained in the present invention include dry strength of 2 to 5'59/
d. Dry elongation is 15-40 inches, dyeability and white skin are normal! J/I/It is on par with textiles, and the texture is particularly soft.
However, the target fiber shrinkage rate of 28- or more can be obtained. Furthermore, it is possible to efficiently produce such highly shrinkable acrylic fibers industrially.

Claims (1)

[Claims] After dry spinning using a spinning stock solution made of an acrylonitrile polymer containing 85% by weight or more of acrylonitrile, it is stretched in hot water at 80°C or higher, and the dry bulb temperature is 140 to 1.
High shrinkage characterized by drying and relaxing fibers at 70°C and wet bulb temperature of 80 to 90°C, stretching them 1.2 to 2 times at 80 to 130°C under dry heat, and rapidly cooling the fibers immediately after stretching. Dry acrylic fiber manufacturing method.