JPS5855244B2 - Method for manufacturing acrylic synthetic fiber filament - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for stably producing acrylic synthetic fibers, particularly long fibers, which are flexible, have excellent gloss and transparency, and have excellent dyeability, with high production. It is something.

Acrylic synthetic fibers have excellent physical properties, develop vivid colors when dyed, have a good texture and bulk, and have excellent heat retention properties, so they have many uses. It is used for.

Among these acrylic synthetic fibers, the texture of knitted fabrics made from long fibers is similar to that of natural silk, making it a useful fiber for expanding its use in the so-called high-end clothing field. is attracting attention as

In addition, acrylic synthetic fibers are manufactured by conventional methods such as wet spinning, dry-wet spinning, and dry spinning, but among these, the fibers obtained by dry-wet spinning are substantially Although it is known to have a smooth surface, a highly glossy appearance, and excellent uniformity of dyeing, it has not been used in this spinning method in the past. The stretching method adopted is a stretching method in hot water or a stretching method in normal pressure steam, so if the stretching speed is increased, the resulting fibers may become fluffy or the uniformity of dyeing may be impaired. It is extremely difficult to produce high-quality fibers at high speeds.

Therefore, the present inventors are currently investigating a method for producing fibers, especially filaments, at high speed with excellent gloss, uniform dyeability, no fuzzing, and a single fiber fineness of 3 denyl or less. The present invention was completed by finding that the object could be achieved by employing a dry-wet spinning method and stretching in a pressurized steam of 2 to 4 kg/crA-G as a stretching method.

The gist of the invention is that at least 9.5 mol % of acrylonitrile and other copolymerizable monomers, especially 0.
．． A spinning stock solution of an acrylonitrile polymer, which is a copolymer containing 2 to 2 mol% of an ionically dissociable monomer and 5 mol% or less of other copolymerizable monomers, is spun by a dry-wet spinning method. The method for producing an acrylonitrile synthetic fiber filament is characterized in that, if necessary, after stretching in hot water, the filament is further stretched in pressurized steam of 2 to 4 kg/cat-G without drying.

The acrylonitrile polymer used in carrying out the present invention has a copolymerization amount of at least 95 acrylonitrile.
The copolymerization amount of mol% and other copolymerizable monomers is 5 mol%
It is as follows.

In order to obtain fibers with elegant luster, uniform dyeability, and excellent viscoelasticity by the method of the present invention, it is necessary that the copolymer used contains 95 mol% or more of acrylonitrile. In particular, when producing fibers having a single fiber fineness of 3 deniers or less and having a feel similar to natural silk, it is preferable that the copolymerized amount of acrylonitrile is 95 mol% or more.

Further, as the copolymerizable monomer to be copolymerized in a proportion of 5 mol% or less, any monomer that can be copolymerized with acrylonitrile can be used, such as vinyl acetate, propion vinyl acid, vinyl chloride, hynylidene chloride, itaconic acid alkyl ester, methallyl alcohol, methyl acrylate, ethyl acrylate, methyl methacrylate, 2-ethyl-hexyl acrylate, acrylamide, acrylamide derivatives such as N-methylol acrylamide, methacrylatyl , styrene, allyl sulfonic acid, methallyl sulfonic acid, styrene sulfonic acid, sulfophenyl methacrylamide, sulfophenyl methallyl ether, sulfopropyl methacrylate, and salts of these acidic monomers, and the purpose of the fiber to be produced; It is preferable to appropriately select these monomers depending on the purpose and the like, and to copolymerize them in combination.

Among the other copolymerizable monomers mentioned above, a monomer containing an ionically dissociable group, especially a vinyl monomer containing a sulfonic acid or a salt thereof, is copolymerized in a proportion of 0.2 to 2 mol%. The acrylonitrile-based polymer has relatively high hydrophilicity, so when fibers are made by the method of the present invention, dense threads without voids can be formed during the coagulation process, and the Its properties are well maintained even during washing and pre-stretching in hot water, so it can exhibit its properties when used as a polymer for producing filaments, which requires particularly strict production conditions. This is preferable from the viewpoint of the fiber manufacturing method, and it is also preferable because the obtained fibers can have even better dyeability and uniform dyeability.

As a method for producing the acrylonitrile polymer, conventionally known suspension polymerization methods, solution polymerization methods, etc. can be used, and vinyl monomers and a polymerization initiator are mixed in water by a continuous method, semi-continuous method, batch method, etc. The polymerization may be carried out by adding a suspension stabilizer if necessary, and an organic or inorganic radical polymerization initiator may be used as the polymerization initiator, but it is preferable to use a redox polymerization initiator.

The degree of polymerization of the polymer used in the present invention is 0.13 to 0.13 when expressed as the specific viscosity of the polymer (0.1 f of the polymer is dissolved in 100 ml of a 0.1 N rhodan soda dimethylformamide solution and measured at 25°C). A value in the range of 0.11 is preferred.

The dry-wet spinning method adopted as a fiber manufacturing method in the present invention is a method in which the above-described acrylonitrile polymer is mixed with an organic solvent such as dimethylformamide, dimethylacetamide, or dimethyl sulfoxide, or a concentrated aqueous solution of an inorganic salt such as rhodan salt or zinc chloride. Alternatively, a spinning dope dissolved in a concentrated aqueous nitric acid solution is extruded at a constant speed through a nozzle placed within a range of 1 to 20 mm above the coagulation bath into the gaseous medium above the coagulation bath, and then the acrylonitrile solvent and non-solvent are extruded into the gas medium above the coagulation bath. For example, this is a spinning method in which the fiber is introduced into a coagulation bath consisting of water, or a coagulation bath further containing an additive such as alcohol.

According to this dry-wet spinning method, the spinning speed can be 5 to 10 times higher than that of conventional wet spinning and dry spinning methods, and the resulting fibers also have better gloss, dyeability, etc. can be made desirable.

Furthermore, in the drawing method employed in the present invention, the coagulated yarn obtained as described above is washed with water and pre-stretched if necessary, and then
Gauge pressure 2-4 kg/crti without drying
This is a method in which stretching is carried out in pressurized steam of -G.

In the above step, the threads are preferably washed in hot water, and the amount of solvent remaining in the threads is preferably 3% by weight or less.

Although water can be used in this washing process, it is better to use hot water, and furthermore, along with this washing with hot water, 1.
．． It is preferable to pre-stretch 8 to 45 times. By adding this pre-stretching step, the stretchability in pressurized steam can be improved, troubles such as yarn breakage can be reduced, and the total It is a preferred method for high-speed spinning, which is the objective of the present invention, as the drawing ratio can be increased, and it is a preferred method for obtaining ultrafine filaments of 3 deniers or less, particularly 1.5 deniers or less. be.

After this washing, the yarn is drawn in pressurized steam at an extremely high ratio of 6 to 12 times without drying. This is not preferable because adhesion occurs between the two, which impairs the feel of the final product.

The most effective way to prevent this adhesion between yarns is to use a method that does not dry the yarns.

For stretching in pressurized steam, the pressure is 2 mm kg/c4-G.
It is necessary that this pressure is 2 kg/crA-
If it is smaller than G, it is difficult to perform high-speed, high-magnification stretching, and stretching unevenness is likely to occur, which is not preferred.

On the other hand, when the pressure is higher than 4kiarlv-G, the drawing ratio of the yarn rapidly decreases, and fusion phenomena frequently occur between individual fibers, which impairs the texture, especially the flexibility, of the resulting fibers. Becomes exposed.

It is necessary to pay attention to the fact that the residual solvent in the yarn during post-drawing can cause fusion between the single fibers of the drawn yarn, and it is usually preferable not to exceed 3% by weight on a dry fiber basis. .

The method of the present invention allows dry-wet spinning of an acrylonitrile polymer to be spun at 2 to 4 kg/cr without drying.
Since the method of drawing in pressurized steam of tt-G is adopted, the drawing ratio is approximately 15% based on the undrawn yarn.
It is possible to draw at an extremely high magnification of about 30 times, and the fiber can be produced at an extremely high speed of 500 to 1500 m/min.

The speed of the yarn after stretching is the product of the take-up speed and the stretching ratio, and is about 500 to 1500 m/min. The drying and relaxation treatment of the obtained yarn can be carried out using methods with high processing efficiency, such as drying roll constant length drying. It is preferable to use a relaxation method, a limited shrinkage relaxation method between rolls, a hot plate relaxation method, a heated steam relaxation method, etc., but the most preferable method is moist heat at 100-200'C or dry heat at 130-200'C. Using conditions of 280'C, 30%
This is a method of performing the following relaxation contraction.

In particular, 0.0% is contained in the acrylic polymer used as a starting material.
If it contains 2 to 2 mol% of an ionically dissociable monomer,
Wet spinning and subsequent drawing in pressurized steam can be carried out extremely smoothly without causing problems such as roughening of the surface shape of the fibers, generation of fluff, or generation of voids.

In addition, since we use an acrylic polymer copolymerized with 95 mol% or more of acrylonitrile as a starting material, the degree of occurrence of the above-mentioned troubles is further reduced, and the resulting fibers have an elegant luster. Because it has dyeability and coloring properties, it is extremely suitable as a filament.

Further, the present invention is a method suitable for producing single fibers with small fineness, particularly fibers with a denier of 1.5 denier/single fiber or less.

In the conventionally known manufacturing method of acrylic fiber,
In particular, there are limitations in spinning and drawing operability, and many difficulties have been encountered when producing single fibers with small fineness, but in the present invention, in addition to the dry-wet spinning method, a specific pressurized steam spinning method is used as the drawing method. Because we use the stretching method,
This makes it possible to produce monofilaments of 3 denier or less, particularly 0.5 to 1.5 denier, at high speed without causing problems such as voids or fuzz in the fiber manufacturing process.

As described above, the fibers obtained by the present invention have high transparency, and can be made into fibers that have a silk-like feel that is graceful and flexible. It was possible to stably produce fibers with no surface defects and excellent dyeing performance at high speed, and its industrial value is extremely high.

The present invention will be explained in more detail with reference to Examples below.

Example 1 A copolymer consisting of 97.2 mol% of acrylonitrile, 2.5 mol% of vinyl acetate and 0.3 mol% of sodium methallylsulfonate with a specific viscosity (0,1 copolymer containing 0.1 N of rhodan soda) After uniformly dispersing 25 parts of an acrylonitrile copolymer (dissolved in 100 ml of dimethylformamide and measured at 25°C) of 0.167 in 75 parts of dimethylacetamide cooled to a temperature of 5°C or less to form a slurry, It was heated to a temperature of 85°C to dissolve it.

The mixture was then subjected to p-filtration and defoamed to obtain a spinning stock solution.

This spinning stock solution is discharged by a gear pump at a discharge rate of 41,2
rd/m1yt, the raw solution was passed through a spinneret with a hole diameter of 0.15 mm and 60 holes through an air medium with a distance of 5 mm between the nozzle surface and the liquid surface of the coagulation bath, and then into a coagulation bath of a 70% dimethylacetamide aqueous solution at 40°C. The fibers were spun using a dry-wet spinning method that leads to

The obtained coagulated yarn was rolled at a roll speed of 100 m/mlyr.
The temperature is 60.70.80°90°C.
During this washing process, the amount of solvent in the fibers is 5% per fiber weight.
It was 1.2%.

Next, preliminary stretching was performed in boiling water in a range of 1.5 to 5.0 times.

This wet yarn was subjected to secondary stretching in pressurized steam having a stretching tube length of 2 rrL without drying.

Table 1 shows the stretching conditions in pressurized steam and the fiber stretching method at this time.

The maximum drawing speed in the table is the speed at which the yarn becomes fluffy and then breaks during the pressurized steam drawing operation.

On the other hand, a stable drawing speed means that the occurrence of fuzz, single fiber breakage, etc. is 10%.
This is a speed that does not occur within hours, and the fineness of the yarn obtained at this speed was defined as the minimum ★★ fineness.

In addition, the threads drawn at each stable drawing speed were continuously passed through an aqueous dispersion of an oil agent containing mineral oil as the main component, and 1.0% of the weight of the fibers was deposited.
The product was dried by passing it through a heating roll at 00°C, and then passed over a hot plate at 270°C to give 10% shrinkage relaxation, and 20 twists per 1rrL were added to form a rolled product.

The results of evaluating the characteristics of these products are also listed in Table 1.

The strength and elongation properties of the filaments in Table 1 are Tensilon UT.
Using an M-III tensile tester, 10 samples of the same material were measured at a yarn length of 200 mm and a tensile speed of 100 mu/min, and the average value is shown.

Worcester thread spot tester type C (Kekkei Kogyo ■
These are the results when measured at a yarn speed of 25 m x 7 mm using a yarn manufactured by Mimaki Co., Ltd.), and all of the samples of the present invention shown in Table 2 had a U% of about 1% and were products with small unevenness in fineness.

The Y value, which indicates the intensity of dyeing of dyed materials, is determined by Hitachi's own spectrophotometric index 1.
Obtained using Model 307.

The staining conditions are as follows.

Measurement sample form Socks knitted fabric dyeing machine Wins dyeing machine Dyeing conditions Sebronflu B 1.0% to fiber weight Diapon T O, 5% to fiber weight Ammonium acetate 50% Bath ratio 1:20 Temperature 95°C for 1 hour and the same Regarding the samples, 50 of the above-mentioned silk fabric samples were prepared and measured, and the results were shown as the average value of the Y values.

From the results shown in Table 1, it can be seen that according to the method of the present invention, fibers with excellent fiber performance can be stably produced at extremely high speed.

In particular, when the preliminary stretching ratio is 1.5 times and less than 5.0 times, fibers with a small fineness of 1.5 denier/single fiber or less can be easily produced at extremely high speeds. I understand.

In addition, the texture of the knitted fabric obtained by further performing false twisting, cheese dyeing, and knitting using the acrylic long fiber obtained in the present invention as a raw yarn is silk-like and flexible. It had excellent dyeing clarity.

Claims (1)

[Claims] 1 at least 95 mol% acrylonitrile and 0.2
A spinning solution containing an acrylonitrile polymer copolymerized with ~2 mol% of an ionically dissociable monomer and 5 mol% or less of other copolymerizable monomers is dry-wet-spun, and if necessary, heated in hot water. 2~4kg/c without drying after pre-stretching with
A method for producing an acrylonitrile synthetic fiber filament, which comprises performing post-stretching in vi-G pressurized steam.