JPS6099003A - Preparation of acrylic yarn - Google Patents

Abstract

PURPOSE:To obtain acrylic yarn having coloring properties with depth, by subjecting a spinning stock solution of an acrylonitrile polymer to set spinning in a coagulating bath having >= critical concentration under specific condition, drawing it in a drawing bath having a specific concentration at high draw ratio. CONSTITUTION:15-20pts.wt. Acrylonitrile polymer having >=85wt% acrylonitrile is dissolved in 100pts.wt. of preferably 63-70wt% nitric acid solution to prepare a spinning stock solution. The spinning stock solution is spun into a coagulating bath (preferably 39wt% nitric acid solution, etc.) having >=critical concentration. In the operation, spinning draft is >=5, and immersion length in the coagulating spinning draft is >=5, and immersion length in the coagulating bath is 30-150cm. The yarn is pulled up, drawn in a drawing bath (preferably 40-48wt% nitric acid solution, at 50-85 deg.C bath temperature) set in a range of the critical concentration +1-+9wt% at >= twice draw ratio, to give the desired yarn.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a wet spinning method for acrylic fibers having deep color development.

Conventional technology Conventional acrylic fibers are dyed with cationic crosslinking, making use of their outstanding weather resistance and pure coloring properties.
Interior fields such as carpets, bedding fields such as blankets,
Widely used in the clothing field such as knits and jerseys.

With the recent diversification of consumer needs, acrylic 4
Cutting fibers are now required to have deeper coloring.

The present inventors have made extensive research into the coloring properties of such acrylic pigments, and have arrived at the present invention.

According to the present invention, an acrylonitrile-based polymer containing at least 85% by weight of acrylonitrile is wet-spun, spun into a coagulation bath having a critical cn degree or higher, and the spinning draft is set at 5% by weight. The immersion length in the coagulation bath is as follows: It was possible to obtain an acrylic tQU' having a certain coloring property.

The critical concentration and Q described in the present invention, the maximum spinning speed is the minimum,
Alternatively, it may not be possible to spin at all, and the concentrations on both sides of the range indicate the solvent resistance of the coagulation bath that has a spinnable region.

When spinning in a coagulation bath having a concentration higher than the critical concentration, the coagulated fibers meander in the coagulation bath, and the resulting fibers become cloudy and completely lose their transparency. therefore,
In conventional spinning, coagulation was performed in a solvent concentration lower than the critical wk degree.

The effects of the present invention will be explained based on the following technical ideas.

In other words, the spinning raw material g discharged into the coagulation bath during wet coagulation
This is known as so-called precipitation coagulation, in which the polymer is precipitated as the solvent concentration decreases.

The coagulated fibers produced by precipitation coagulation contain a varying concentration of solvent in the coagulation bath between the precipitated polymers, forming an extremely I-lase structure. The space occupied by the solvent is mm between water and water during washing.
After that, in the drying process, the fibers are crushed as water evaporates, and the precipitated polymers adhere to each other to form acrylic fibers.

In order to improve the optical uniformity of the fibers, it is important to make the areas in close contact with the precipitated polymers uniform. By fluidizing the coalescence and stretching it at the same time, the wall-to-wall portion between the precipitated polymers was compressed and the adhesion of the precipitated polymers was improved.

The re-soaking treatment of the coagulated fibers in a solvent requires fluidization of the precipitated polymer, and under such conditions, the coagulated fibers obtained by coagulation using the 119 method can be as large as mm.

The precipitated polymer becomes faster in the thinner Ti bath Ml and closer to the thicker Ti bath Ml. By making the six layers of the precipitated weighted body layer of coagulated fibers thicker and the inner part thinner, it is possible to fluidize the inside and make the can circumferential without having to cut the CD layer of coagulated fibers. It is only through the integral combination of the coagulation method that eliminates the dryness of the coagulated fibers and the stretching process (in step 6) that the coagulation method has certain conditions, that optical uniformity can be achieved with great depth and depth. Acrylic fibers with color-forming properties T- are obtained.

The technical means of making the coagulated fiber structure thicker on the surface and thinner on the inside can be obtained by coagulating it with a commercial spinning draft in a coagulation bath with a bath agent that is much larger than the critical one. It will be done.

When coagulated fibers with precipitated polymers gathered in a thick layer on the fiber surface are stretched in a solvent bath, they can be stretched at a high stretching ratio without dissolving, and the fibers after stretching can be drawn with a scanning electron beam. When observed under a microscope, it is observed that the white area occupied by the rM agent has decreased and the precipitated polymer is densely layered over the entire fiber cross section.

In the stretching treatment of fibers in a solvent bath, it goes without saying that the solvent concentration and temperature of the FD agent bath both have upper limits and are set within a range that does not dissolve the coagulated fibers.

The acrylic polymer used in the present invention is obtained by copolymerizing 85% (hereinafter abbreviated as "C") or more acrylonitrile and a monomer copolymerizable with acrylonitrile by a conventional method.

The polymerization method for these copolymerizers may be any method as long as it is a method for polymerizing vinyl yarn monomers that are commonly used. An example is an aqueous suspension system using a redox catalyst.1. )I+j
,-I! , 3tsujkdmu moeire 6μy moe (- stirrup fada is required. However, this @aki is not affected in any way by the polymerization method and polymerization conditions. Examples of the monomers used in the present invention are: , acrylic acid and its alkyl esters, methacrylic acid and its alkyl esters, acrylamide, methacrylamide, maleimide, β-aminoethyl methacrylate, acrylamide, methacrylamide, vinyl acetate, vinyl chloride, vinylidene chloride, allylsulfonic acid and its ammonium salts , metal salts, amine salts, etc., but are not limited to these.

The polymer thus obtained is dissolved in nitric acid, a zinc chloride aqueous solution, a Rodan salt aqueous solution, dimethylformamide, etc. to prepare a spinning stock solution t. Particularly preferred in the present invention is a nitric acid aqueous solution.

When using nitric acid as the rd agent, for 100 parts of nitrate Me solution with nitric acid la degree 60.-80%, preferably 63-70%,
The polymer is dissolved in an amount of 10 to 40 parts, preferably 15 to 20 parts, and the temperature of the stock solution during dissolution is kept at 20C or less in order to suppress the oxidation reaction by 1 nitrate to obtain a spinning stock solution. Then, this spinning solution is spun into a coagulation bath having a critical temperature of 1 or more times.

The critical concentration in wet spinning using nitric acid as a bath agent varies depending on the solvent used, the polymer concentration, the coagulation bath once, etc., but is centered around 39 degrees. Similarly, when dimethylpolamide is used as a solvent, 1 pigeon is 5
It is present in the vicinity of 3%, and in the case of a zinc chloride-based bath additive, it is present in the vicinity of 40%.

Spinning using nitric acid as a bath agent is performed using a nozzle that can set a spinning draft of more than 5 in a coagulation bath whose nitric acid concentration is adjusted to tbi of 40% or more, preferably 48% or less.

Here, the spinning draft rate is expressed by the following formula.

Spinning draft = (winding roller speed) / (linear speed of spinning dope discharged from the nozzle hole) If the coagulation bath has less than the critical concentration, the spinning draft will not reach 5, and the resulting fiber will have deep coloring. poor. If the coagulation bath exceeds the critical concentration +9, adhesion between fibers and swamp formation are likely to occur.

If the spinning draft is less than 5, the fibers will sag in the coagulation bath, and the fibers will wrap around the rotating parts, reducing spinning operability. become scarce.

When the spinning trough If-5 is exceeded, the fibers are stretched in a straight line in the coagulation bath, and the higher the spinning draft, the deeper the color development of the resulting fibers.

If the immersion length in the coagulation bath is shorter than 30 tyn, the hardness will not be sufficient, and adhesion between the fibers will be observed in the resulting fibers, which is not good.
The long immersion time in the IJf-1-1 bath is undesirable, as the protrusion of the low molecular weight body into the coagulation bath increases.

The fibers thus obtained were washed with water and ii+i'J'c
If it is removed at 100° C. and then stretched and dried, deep color development cannot be obtained. For the first time, it is possible to obtain acrylic fibers with deep length and strength.

When coagulated fibers that do not satisfy the coagulation conditions of the present invention are subjected to solvent drawing treatment under the conditions specified in this specification, the coagulated fibers may dissolve in the solvent drawing bath or adhesion between the fibers may occur. At the same time, the resulting fibers lack deep color development.

When using nitric acid, preferably the concentration of the solvent drawing bath is 40
% to 48 inches, the bath temperature is 50 to 85°C, and the stretching ratio is 2 times.

The higher the concentration of the solvent stretching bath, the easier it is to obtain deep coloring properties. If the critical concentration is less than +1%, the deep coloring properties will be poor and the drawability will also deteriorate. If the critical concentration is above +9 Adhesion between fibers, 114 adhesion, is likely to occur.

The higher the temperature of the solvent stretching bath, the deeper the color development can be obtained, but at a temperature of less than 500°C, the stretching property decreases, and at a temperature of over 85°C, adhesion between fibers tends to occur.
50-85°C is preferred.

The higher the stretching ratio in the solvent stretching bath, the deeper the color development can be obtained. When stretched at a stretching ratio of less than 2 times in a solvent stretching bath, deep color development Q is poor.

Fibers produced within the scope of the present invention are subjected to regular water washing treatments to remove less than 0.1% solvent. The washing method may be any commonly used method such as immersion (dry water washing, net washing, vibro washing, etc.).

Since the strength of the fibers is low, it is better to re-draw them in hot water or steam, but even in this case, the color will still be deep. 1' will not drop. That is,
RD agent LI; 1111 (If the fiber has been stretched by more than 2 times, there is no problem in re-stretching it depending on the purpose.

The fibers from which the solvent has been removed or the fibers that have been redrawn after the solvent has been removed do not dry, and the moisture contained in the fibers is removed. As a drying method, a known method such as a commonly used drum dryer, cylinder dryer, net dryer, etc. may be used.

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

As a method for thermal relaxation, any method may be used as long as the material can be contracted in a heated atmosphere such as in high-pressure steam, hot air, hot water, or between hot plates. Furthermore, even if the fibers from which water has been completely removed are stretched in pressurized steam, the deep color development does not deteriorate.

The deep color development is measured by visual sensory evaluation criteria, and the acidity is poor.

As a result of intensive research into deep color development, we discovered that it greatly depends on the amount of light transmitted in the fiber axis direction. The relationship between the amount of transmitted light of the fiber and the deep color development obtained in experiments including comparative examples and examples can be seen in the shaded area in the graph of FIG.

To measure the amount of transmitted light, create a fiber bundle with a length of 2 mm using the fiber bundle fixing device shown in Figure 1, and then attach the fiber bundle to an Olympus BH-
Using a type 2 microscope with a white light source and a magnification of 100 times without a filter, adjust the field of view to the area showing average brightness with a white light source and measure the exposure time. The reciprocal of the exposure time is the amount of transmitted light, expressed in units of asc-'.

For the sample for determining the amount of transmitted light 6, pass the fiber 4 through part of the fiber bundle fixing device shown in Fig. 1 (Fig. 2 shows its side), and then apply a load 7 of 200y with the presser metal fitting 2. , presser metal fitting 2
are fixed with a set screw 3, and then the parts protruding from the flat part of the fiber bundle fixing device (Fig. 2) are cut out accurately with a knife. I can do it.

The amount of transmitted light is affected by the degree of fiber filling. (Therefore, the fibers for which the total amount of transmitted light is measured have the same 181-plane shape and 4-
It is significant only when the denier is S'9! F.

not.

The degree of deep color development is 3.5 compared to the 2.5 grade of commercial products.
If you are above grade level, you can tell the difference at a glance.

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

Example 1 Using a combination of ammonium persulfate and acidic sodium sulfate as a polymerization catalyst, sulfur was added to Pit 2.5 +Fl'J
r Polymerization was carried out in lightened water at 55°C for 5 hours, and acrylonitrile/methyl acrylate/sodium methallylsulfonate = 91/8.510.5 (monomer preparation!
A polymer was obtained. 67% of this polymer at 0℃
It was dissolved in a ratio of 16 g to 100 g of nitric acid aqueous solution to obtain a spinning stock solution.

Then, it was discharged into a 5°C coagulation bath having a nitric acid concentration of the batter 1 using a nozzle with a hole diameter of 0.20 and a number of holes of 100,
It was removed from the coagulation bath at a rate of 12 yn/day, and then the nitric acid t11. It was stretched 1000 times in a Yuya bath with a concentration of 42 cm and a bath temperature of 70C. Immersion length in coagulation bath is 50cr
It was set as n. The stretched fibers were washed with water, thoroughly dried in hot air at 130°C, and subjected to thermal relaxation treatment in steam at 120°C.

In Comparative Example 1, the nitric acid concentration in the coagulation bath was less than 40%,
The fibers were broken at a spinning draft of 6.7 in the pseudo solid bath, and the fibers could only be taken out at a spinning draft of 0.7 or less. In addition, in the soft ratio example 2 where the coagulation bath nitric acid concentration was 49%, there was a lot of adhesion between the fibers, and the transparent stitch was low.
No elegant color development was obtained.

On the other hand, in Inventive Examples 1 and 2, there was no fiber cutting in the coagulation bath or adhesion between fibers, and the obtained Omu IE had a high amount of transmitted light and deep color. .

1-1 By the way, the amount of transmitted light of commercially available products is 6. ．． 2 X l Ose
It is grade 25 for deep color development.

Example 2 100 g of the 65-1111 acid aqueous solution of 5C obtained in Example 1 was mixed with 15 g of d) to prepare a spinning stock solution. Next, the Niba Butsu mode is 42 degrees, and the bath temperature is IW 5 degrees Celsius.
The length of the coagulation bath was 70 crn, and the coagulation bath was taken out at a speed of 10 m1, and the nitric acid concentration was 44%. It was stretched 1010 times in a RILL stretching bath with a bath temperature of 70C.
The chestnuts were dried in hot air at 130'C for 7 minutes and subjected to heat relaxation treatment at 120'C.

In Ratio I Yield Example 3 and Comparative Example 4, in which the draft in the coagulation bath was 5 or less, the transparency was poor.

In Inventive Examples 3.4 and 5, acrylic fibers with extremely deep coloring properties were used. I was able to do it.

Example 3 Polymerized metal bar obtained in Example 1 67% nitric acid aqueous solution at 7°C 100%
I was divided into 18g portions and used as a spinning dope. Then, 0.3
The coagulated yarn was discharged using a spinning nozzle with a hole diameter of 11I, and the soaking length of the coagulated yarn was 70 cm. After taking it out from the coagulation bath at a speed of 20 m/mm, it was immediately drawn into a solvent drawing bath at the nitric acid concentration and bath temperature shown in Table 3. Processed. The film was stretched 5 times in a solvent stretching bath, thoroughly washed with water in a immersion #1 water washer, and then stretched 1.5 times in boiling water. After that, it was dried in a hot air dryer and then subjected to thermal relaxation treatment in steam at 125°C.

Comparative Example 5 has a low nitric acid concentration of 38% in the solvent drawing bath, Comparative Example 6 has a crystalline solvent drawing bath nitric acid concentration of 50%, and Comparative Example 7 has a low nitric acid concentration of 45°C in the solvent drawing bath. However, the amount of transmitted light decreased, and deep color development could not be obtained.

Solvent drawing bath nitric acid 4%: 41%, 44%, 48% respectively
In Examples 6, 7, and 8 of the present invention, fibers i4f- were obtained in which the amount of light in both the transparent and transparent fibers was increased and the color development was deep.

In addition, in Comparative Example 9 where the temperature of the m-agent drawing bath was as high as 90°C, adhesion between fibers occurred and the amount of transmitted light was also low. 2) IJ/methyl acrylate/acrylamide/sodium methallylsulfonate = 90/6/3/IC single M.

Polymerization was carried out according to the ratio of the amount of A to be charged. The thus obtained polymer was added to 100 I of a 66% nitric acid aqueous solution at 6°C.
It was dissolved in a proportion of 17 g to obtain a spinning stock solution. followed by 44%
A pore size of 0.7 myi was placed in a coagulation bath at 6 °C with a nitric acid concentration of
, Discharge using a nozzle with 50 holes, and soak the coagulated thread for a length of 25 crn and 100 cm.

The film was taken out from the coagulation bath with a continuous flow rate of 1 orn/min, and then stretched to the stretching ratio shown in Table 4 in an RD agent stretching bath with a nitric acid concentration of 42% and a bath temperature of 65°C.

The fibers that had been subjected to solvent stretching were washed with water under no tension using a net type water washer to reduce the concentration of nitrate #R-summer rO in the fibers to 11% or less. Thereafter, it was stretched in boiling water and steam at 110° C. at the ratio shown in Table 4. The thus obtained fibers were dried using a normal hot air dryer and then subjected to a thermal relaxation treatment using steam at 128°C.

Comparative Example 1O with a low stretching ratio of 1.51 in a solvent stretching bath
The amount of transmitted light was small, and the color development was poor. On the other hand, Example 9 of the present invention was subjected to solvent stretching by 2.0 times or more.
1O and 11 are after water washing, hot water stretching, high pressure steam stretching,
Alternatively, even when both hot water stretching and pressure steam stretching were performed, the amount of transmitted light was high, and acrylic fibers with ←d-like coloring properties were obtained.

In Comparative Example 11, in which the length of immersion in the coagulation bath was short, although a deep degree of color development was obtained, the adhesion between the fibers was severe and the commercial value was low. In Comparative Example 12 where the immersion length in the coagulation bath was long, the elution Ft of the polymer into the coagulation bath was not the best.

[Brief explanation of drawings]

FIG. 1 is a front view of the fiber bundle fixing device, where l is a fiber bundle fixing groove, 2 is a presser metal fitting, and 3 is a set screw. Figure 2 is a lateral view of the fiber bundle fixing device a, 41:i 1
The fiber bundle installed in the section, 5 is the fiber bundle fixing ring 1 (clothing II!
I+ %6 indicates the back side.

Claims (1)

[Claims] 1. When wet-spinning an acrylonitrile polymer containing at least 85M plate% or more of acrylonitrile,
Hosho T & Jl [spun into a coagulation bath with a spinning draft of 5 or more and an immersion length in the coagulation bath of 30 to 150 cr
1. A method for producing acrylic fibers, which comprises stretching the fibers within a range of n, and then drawing the fibers to twice or more in a drawing bath set at a critical density of +1 to +9%.