JP2003286614A - Spinning dope containing viscosity improving agent and fiber obtained by wet spinning the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spinning dope improving the viscosity which is one object of measures for improving material handling in an acetone solution of an acrylic polymer obtained by polymerizing acrylonitrile, vinyl chloride and a sulfonic acid group-containing vinyl monomer as principal components, and to provide fibers obtained by wet spinning using the spinning dope. <P>SOLUTION: The spinning dope is the acetone solution obtained by polymerizing the acrylonitrile, vinyl chloride and sulfonic acid group-containing vinyl monomer as the principal components and mixing the resultant acrylic copolymer with a viscosity improving agent. The acetone solution comprises the viscosity improving agent in which the Non-Newtonian index of a 15 wt.% solution of the polymer at 40°C exhibits 0.6-1.0. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an acetone solution prepared by mixing an acrylic copolymer containing acrylonitrile, vinyl chloride and a vinyl monomer having a sulfonic acid group as a main component with a viscosity improver. Polymer 15% by weight
The non-Newtonian index at 40 ° C. of the solution is 0.6 to 1.
The present invention relates to a spinning dope showing 0, and a fiber obtained by wet spinning using the same.

[0002]

2. Description of the Related Art A spinning stock solution composition in which an acrylic copolymer obtained by copolymerizing acrylonitrile, vinyl chloride and a vinyl monomer having a sulfonic acid group as a main component is dissolved in acetone may be dimethylformamide, dimethylacetamide or It is recognized that the structural viscosity is stronger than that of a solution of the spinning dope dissolved in dimethyl sulfoxide. After understanding this characteristic, conventionally, wet spinning is carried out by adjusting the viscosity by setting a stock solution condition suitable for existing spinning equipment, that is, a stock solution concentration that does not hinder material handling. On the other hand, in such wet spinning,
It is generally known that the higher the polymer concentration in the spinning dope, the more dense the solidified structure during spinning and the more favorable the various physical properties. Therefore, in wet spinning, it is preferable that the concentration of the polymer in the spinning dope is as high as possible so long as it does not hinder material handling.

By the way, the conventional acrylic fiber obtained by spinning the acrylic copolymer is not sufficiently satisfactory in dyeability, and there has been a demand for improvement in dyeability for some time. As a countermeasure, attempts have been made to increase the copolymerization ratio of the sulfonic acid group-containing vinyl monomer serving as the dyeing seat. However, when the copolymerization ratio of such a sulfonic acid group-containing vinyl monomer is increased, the viscosity of the spinning stock solution in which the copolymer is dissolved in acetone becomes high, so the polymer concentration of the spinning stock solution is unavoidably reduced to perform spinning. There is a need.
As a result, the liquid content of the gel-like fiber in the spinning process becomes high and the fiber cross-sectional structure after coagulation becomes rough, resulting in brittle fiber strength, which causes manufacturing problems. There was a limit to the copolymerization ratio of the acid group-containing vinyl-containing monomer.

Therefore, the prior art was investigated from the viewpoint of reducing the viscosity of the spinning dope. Regarding the spinning technology, as shown in, for example, JP-A-7-41597 and JP-A-8-157596, spinning during melt spinning was performed. Although many studies have been made on the technique for reducing the viscosity of the stock solution, the method for reducing the viscosity of the stock solution by wet spinning, especially when spinning an acetone solution of an acrylic copolymer has not been studied, and the technology has not been established. The current situation is that it has not been done. In addition, JP-A-9-3
No. 722 discloses a stock solution for an acrylic precursor, but the copolymer used is a copolymer of acrylonitrile and a vinyl group-containing lower carboxylic acid, and the solvent is a good solvent for the polyacrylonitrile polymer. Is an organic solvent such as dimethylformamide, dimethylacetamide, or dimethylsulfoxide, or an aqueous solution of zinc chloride, thiocyanate, or the like. However, in the acetone solvent used in the present invention, the polymer becomes insoluble, and the amount of the organic carboxylic acid added is 5% by weight or more of the polymer stock solution to promote gelation. Since the acrylic copolymer having vinyl as a main component exhibits a different dissolution behavior from that of the acetone solution, it is an essentially different stock solution preparation technique, and is a technical disclosure unsuitable as a technique for achieving the object of the present invention.

[0005]

DISCLOSURE OF THE INVENTION An object of the present invention is to improve a material handling by acrylonitrile,
Spinning stock solution viscosity of an acrylic solution of an acrylic copolymer obtained by polymerizing vinyl chloride and a vinyl monomer containing a sulfonic acid group as a main component is reduced, and fibers obtained by wet spinning using the spinning stock solution are prepared. To provide.

[0006]

[Means for Solving the Problems] The present inventors have hitherto been proposed to increase the copolymerization ratio of a sulfonic acid group-containing vinyl monomer in an acrylic copolymer mainly composed of acrylonitrile and vinyl chloride. As a result of investigating by focusing on the phenomenon that the viscosity of the acrylic copolymer acetone solution increases,
The present inventors have found that the involvement of sulfonic acid groups is large in relation to the structural viscosity, and further that the presence of a polar low molecule in the solution can reduce the viscosity of the spinning dope, resulting in the present invention.

That is, the present invention provides (1) the following components (A),
A spinning dope containing component (B) and component (C), wherein the amount of component (B) is in the range of 0.1 to 100 parts by weight per 100 parts by weight of component (A), and The non-Newton index at 40 ° C. is 0.6 to 40 when the concentration of the component (A) is 15% by weight when the total amount of the components (A), (B) and (C) is 100% by weight. 1.0
A stock solution for spinning: (A) an acrylic copolymer mainly composed of acrylonitrile and vinyl chloride, in which the composition ratio of the sulfonic acid group-containing vinyl monomer is 1 to 3% by weight, ( B) Viscosity improver, (C) Acetone.
(2) The viscosity improver which is the component (B) is active hydrogen or /
And the spinning dope as described in (1), which is an organic compound having a polar group. (3) The spinning dope according to (2), wherein the organic compound having active hydrogen and / or a polar group is an organic acid salt. (4) The spinning dope as described in (1), wherein the viscosity improver which is the component (B) is an inorganic salt. (5) A fiber obtained by wet spinning the spinning dope of (1) to (4). Can be achieved by

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The acrylic copolymer as the component (A) in the present invention is obtained by copolymerizing acrylonitrile, vinyl chloride and a vinyl monomer having a sulfonic acid group as main components. It is a thing. Sulfonic acid group-containing vinyl monomer is an essential component for improving the dyeability of the acrylic copolymer, the composition ratio of the sulfonic acid group-containing vinyl monomer in the acrylic copolymer is usually It is 1 to 3% by weight, preferably 1.2 to 2.7% by weight, and more preferably 1.5 to 2.5% by weight. If the amount of the sulfonic acid group-containing vinyl monomer is less than 1% by weight, it can be used as a commercial acrylic fiber in the case of using a accelerating dye together with a cationic dye when dyeing a dark color or requiring a long dyeing time. If the dissatisfaction with the dyeability is poor, and if the content exceeds 3% by weight, the coagulability during spinning is insufficient, and as a result, there are many problems in fiber production and it tends to be difficult to form fibers. The composition ratio of acrylonitrile is usually 30 to 55% by weight, preferably 40 to 53% by weight, more preferably 45 to 52% by weight.
The composition ratio of vinyl chloride is usually 44 to 69% by weight, preferably 46 to 59% by weight, and more preferably 47.
% To 54% by weight, and the acrylic copolymer of the present invention may have a composition in which one or more vinyl monomers are further copolymerized. It may be a mixed composition with another polymer soluble in a solvent. If the copolymerization amount of acrylonitrile is less than 30% by weight, the wool-like texture that is characteristic of acrylic fibers cannot be obtained when formed into fibers, and if it exceeds 55%, the polymer is dissolved in acetone which is a solvent. Since it deteriorates the properties, special equipment of high temperature and high pressure is required, and it is not suitable as a spinning stock solution because it is difficult to handle.

The sulfonic acid group-containing vinyl monomer in the present invention is not particularly limited as long as it is a sulfonic acid group-containing vinyl monomer copolymerizable with acrylonitrile and vinyl chloride, but is not limited to methallyl sulfonic acid and allyl sulfonic acid. , Isoprene sulfonic acid, styrene sulfonic acid, 2-
Representative examples thereof include acrylamido-2-methylpropanesulfonic acid, sulfophenylmethallyl ether, and their sodium, potassium, and ammonium salts.

Other vinyl monomers copolymerizable with one or more of the above are acrylic acid and methacrylic acid and their lower alkyl esters, N- or N, N-alkyl substituted aminoalkyl esters and glycidyl esters, acrylamide and methacrylic acid. Amide and N- or N, N-alkyl-substituted product thereof, carboxyl group-containing vinyl monomer represented by acrylic acid, methacrylic acid, itaconic acid and the like, and anionic vinyl monomer such as sodium, potassium or ammonium salt thereof Vinyl monomer including quaternary aminoalkyl ester of acrylic acid or methacrylic acid, vinyl group-containing lower alkyl ether, vinyl group-containing lower carboxylic acid ester represented by vinyl acetate, vinyl bromide , Vinylidene cyanide, vinyl bromide Den or vinylidene chloride can be mentioned but not limited to monomers.

In the present invention, it is possible to reduce the viscosity of the spinning dope by adding a polar low molecule to the spinning dope prepared by dissolving the acrylic copolymer as the component (A) in the acetone as the component (C). I found it. As the viscosity improver which can be mixed, an organic compound having active hydrogen or / and a polar group is preferable, and among them, a compound having a high acid dissociation constant pKa value is preferable from the viewpoint of metal corrosion. Examples of the compound include a hydroxyl group, a thiol group, an amino group, a compound having hydrogen in an atomic group directly bonded to a hetero atom such as boron, silicon, or phosphorus, or an electron donating property to an α-position carbon to which hydrogen is bonded, Examples thereof include organic compounds having an electron-withdrawing atomic group. Among them, glycolic acid, lactic acid, oxybutyric acid, which are organic acids having a hydroxyl group or an amino group,
Glyceric acid, tartronic acid, malic acid, tartaric acid, citric acid, oxy acids represented by mandelic acid and tropic acid, glycine, alanine, valine, leucine, isoleucine,
Cysteine, cystine, methionine, aspartic acid,
Amino acids represented by glutamic acid, lysine, arginine, phenylalanine, tyrosine, proline, histidine and tryptophan or oxyamino acids represented by serine, threonine and oxyproline, and lower haloalkylcarboxylic acids such as chloroacetic acid, chloropropionic acid and chlorobutyric acid. Acids and their sodium, potassium, ammonium calcium and magnesium salts are preferred, and the aforementioned salts of formic acid are also preferred. In addition to the carboxylic acid derivatives, lower alkyl esters of acetoacetic acid or malonic acid, γ-butyrolactone, N-methylpyrrolidone, organic compounds represented by active groups such as benzyl chloride and having a polar group are also preferable. Examples of the oligomers include amidophosphazene oligomers. In addition, acid amide compounds such as dimethylformamide and dimethylacetamide, which are components that constitute the solvent of the acrylonitrile-based polymer, oxygen-containing sulfur compounds such as dimethyl sulfoxide and tetramethylene sulfone, and carbonate esters such as ethylene carbonate and propylene carbonate are also preferable. . In addition, sodium and ammonium salts such as potassium thiocyanate, which is a component constituting the inorganic solvent of the acrylic copolymer, salts such as zinc chloride and calcium nitrate, or water can also be used as the viscosity improver. Of course, two or more kinds of such viscosity improvers may be used in combination. On the other hand, non-polar compounds such as benzene and heptane are not preferable because they have almost no viscosity reducing action. Further, if the acid dissociation constant pKa value is too low, the effect of improving the viscosity is recognized, but it cannot be said to be a preferable viscosity improving agent from the viewpoint of corrosiveness.

The molecular weight of the compound serving as the viscosity improver which is the component (B) is 1,000 or less, preferably 500 or less. When it exceeds 1000, a viscous action due to the compound is added, which is not preferable.

The ratio of the viscosity improver which is the component (B) is
It is 0.1 to 100 parts by weight, preferably 0.3 to 50 parts by weight, and more preferably 0.5 to 30 parts by weight with respect to 100 parts by weight of the acrylic copolymer as the component (A). However,
In the case of water, it acts as a coagulant for wet spinning,
The amount of addition of the polymer in an acetone solution does not gel, and is preferably 20 parts by weight or less, although it depends on the concentration of the polymer. If it is less than 0.1 part by weight, the non-Newtonian index, which is one of the properties of the stock solution, which does not increase, is not greatly affected by the structural viscosity, and if it exceeds 100 parts by weight, the dissolution and dispersion in the stock solution is uniform. In terms of the properties or the use of the polymer, the proportion of the viscosity reducing agent remaining is increased, and physical properties, discoloration, or changes with time thereof are remarkable, which is not preferable.

Here, the non-Newtonian index can be treated as a numerical value indicating a behavior deviating from the Newtonian flow behavior in the flow curve, and is obtained from the equation (1).

S = μD ^{n In the} equation (1), s shear stress, μ is a non-Newton coefficient, D
Means velocity gradient and n means non-Newtonian exponent. For Newtonian fluid, n = 1 and μ is expressed as viscosity η, but for fluids having structural viscosity, 1>n> 0. As the non-Newtonian index approaches 1, the contribution of the structural viscosity becomes smaller, so that the fluidity of the fluid is improved, and the material handling property at the time of the low shear rate of the fluid is improved when the undiluted solution is fed.

The viscosity improvement evaluation of the spinning solution is as follows.
The total of the components (A), (B), and (C) is 1
The non-Newtonian index at 40 ° C. when the component (A) concentration is 15% by weight when the amount is 00% by weight is preferably 0.6 or more and 1.0 or less. More preferably, it is 0.8 or more. When it is less than 0.6, the structural viscosity is remarkable, and the material handling during feeding the undiluted solution, particularly the increase in the filtration pressure in the filtration step is remarkable, and continuous handling becomes difficult.

The viscosity improver may be added directly or as a solution of water or acetone to a monomer mixture as a raw material before polymerization, to a copolymer after polymerization, or to the copolymer. The spinning stock solution of the present invention can be obtained by, for example, adding it to an acetone solution.

For the present wet spinning, the spinning dope of the present invention is preferably adjusted to a value of 20 to 500 dPa · sec as measured by a rotational viscometer (B type viscometer) at 40 ° C. When the viscosity of the spinning dope is less than 20 dPa · sec, the solidification structure in the coagulation bath becomes rough and the continuity of the solidified polymer tends to be poor, and the spinning nozzle tends to be poorly spun. , If it exceeds 500 dPa · sec, it becomes difficult to remove the gas entrained during stirring and dissolution, and if the reduced pressure removal method is performed, acetone will also evaporate, and it will be necessary to devise the concentration control, and the filtration pressure of the spinning dope will increase. May cause trouble and is not preferable. The spinning dope of the present invention prepared as a spinning dope is spun into fibers by an aqueous wet spinning method using a known acetone solvent. At this time, the acetone concentration in the coagulation bath is 0 to 5
0 wt% and temperatures of 5-40 ° C are generally applicable.

In the present invention, the reason why the viscosity of the spinning dope is reduced by the presence of a polar low-molecular compound in the spinning dope is not clear, but it is considered that the following phenomena are involved. In an acetone solution of an acrylic copolymer, a viscosity increasing tendency appears when the copolymerization ratio of the sulfonic acid group-containing vinyl monomer is 1% by weight or more, and when the copolymerization ratio is 1.2% by weight or more, it becomes remarkable, and further, When it is 1.5% by weight or more, it becomes extremely remarkable. This means that the sulfonic acid group present in the copolymer molecule acts as an extremely weak pseudo-crosslinking or intermolecular interaction with another adjacent copolymer molecule due to a physical action such as van der Waals force. It is thought that as a result, the apparent molecular weight increases and the resistance of molecular flow increases and the viscosity increases. The sulfonic acid group is involved in the H atom bonded to the α-position carbon to which the Cl group or the CN group of the copolymer is bonded, or the sulfonic acid group directly adjacent to the solvent, or acetone which is a solvent. Indirect sulfonic acid groups and the like intervening with are conceivable. Therefore, it is considered that the structural viscosity can be improved by adding an alternative action destination so that the action of the sulfonic acid group bonded to the copolymer does not affect other adjacent copolymer molecules. As the additive, it was considered that a low molecular weight compound having a polar property, which is difficult to chemically react with an acrylic copolymer or acetone, is applicable.

[0020]

EXAMPLES The present invention will be further described below based on Examples, Comparative Examples and Reference Examples, but the present invention is not limited to these Examples. In addition, all the percentages of chemical compositions used are% by weight. Further, the draw ratio in the fiber manufacturing process is a value obtained by rounding off the second decimal place, and the relaxation rate is expressed as a percentage with respect to the fiber length before the relaxation treatment. In addition,
Prior to the description of the examples, sample adjustment and evaluation methods were carried out by the following methods.

(Non-Newton index): Cone plate type viscometer (E type viscometer type VISCONIC ED
Mold, manufactured by Toki Sangyo Co., Ltd., and data processing was performed using a viscosity measurement / data processing program VA2000 for R series viscometer (also manufactured by Toki Sangyo Co., Ltd.). In addition, in the measurement, after putting the sample in a sample cup in which constant temperature circulating water at 40 ° C was passed and setting it, measure it once and let the sample adapt to the measurement conditions, and obtain the value obtained in the second measurement. The value was rounded off to the third decimal place and used as the measured value.

(Undiluted solution viscosity): Single cylinder type rotational viscometer
It was measured using a Bismetron type VSA (Shibaura System Co., Ltd.).

(Examples 1 to 13) Acrylonitrile 50
%, Vinyl chloride 48.5%, and sodium styrenesulfonate 1.5%, in an amount corresponding to 1 part by weight per 100 parts by weight of the copolymer (Table 1 A non-Newtonian index was determined by adjusting the acetone solution containing the acrylic copolymer at a concentration of 15% by mixing the viscosity improver shown in (4). Since ammonium formate, DL-calcium lactate, and amidophosphazene oligomer have low solubility in acetone, they were pulverized into a mixed solution. The results are shown in (Table 1). The non-Newtonian index approaches 1 as compared with Comparative Example 1 described later,
This means that the flowability of the acetone solution of the copolymer was improved because the contribution of structural viscosity was reduced.

[0024]

[Table 1] (Examples 14 to 16) The dimethylacetamide used in Example 9 was mixed by changing the addition amount, and the non-Newton index was obtained in the same manner as in Example 9. The results are shown in (Table 2). As in the case of the above-mentioned example, the non-Newtonian index was closer to 1 and the contribution of structural viscosity was reduced, which means that the fluidity of the acetone solution of the copolymer was improved, as compared with Comparative Example 1 described later.

[0025]

[Table 2] (Comparative Examples 1 to 3) Acetone solution of acrylic copolymer having a concentration of 15%, which is composed of the copolymer used in Examples 1 to 16 and acetone without addition of a viscosity improving agent (Comparative Example 1),
And an acetone solution having a concentration of 15% of an acrylic copolymer obtained by adding and mixing 5.7 parts by weight of heptane, which is a nonpolar solvent, to 100 parts by weight of the copolymer (Comparative Example 2),
Further, the results of determining the non-Newton's index of each acetone solution of the acrylic copolymer mixed with benzene instead of heptane (Comparative Example 3) are shown in Table 3. From Table 3, it is meant that the contribution of structural viscosity is large because the non-Newton exponent is small, and the viscosity of the solution is large at a low shear rate.

[0026]

[Table 3] (Example 17) Acrylonitrile 50%, vinyl chloride 4
Acrylic copolymer consisting of 8% and sodium styrenesulfonate 2% was mixed with 100% by weight of the copolymer and 0.60 parts by weight of finely ground ammonium formate was added and mixed in acetone. And dissolved to obtain a spinning dope having a copolymer concentration of 26%. This stock solution is 40 ℃
Shows a viscosity of 260 dPa · sec.
The non-Newtonian index when diluted to% was 0.81. A spinning nozzle (hole diameter 0.20 mm, number of holes 2)
00) and spun into a coagulation bath consisting of 10 ° C. and 10% concentration acetone water. Then, it was introduced into a bath composed of 45% acetone water at 25 ° C., stretched 2.7 times, and passed through a bath composed of 15% acetone water. After that, it was passed through a washing bath composed of warm water of 40 ° C. and further stretched 1.3 times in a hot water bath of 85 ° C., after which an oil agent was attached and dried at 120 ° C. Subsequently, it was stretched 1.7 times at the same temperature and then subjected to 10% relaxation treatment at 145 ° C. to obtain a fiber.

[0027] In the process of spinning from the stock solution adjustment to the final fiber, various problems such as the liquid sending property of the stock solution, the tow breakage in each bath including the spinneret stand and the coagulation bath, and the winding around the roller are caused. The process is stable, and the acrylic copolymer discharged from the spinning nozzle is produced in 1 hour of fiber production after the continuous yarn drawing work from the spinning nozzle stand up to the final relaxation treatment is completed. It was possible to make fibers that were subjected to all-amount relaxation treatment.

(Comparative Examples 4 and 5) The acrylic copolymer used in Example 17 was dissolved in acetone containing no ammonium formate to adjust the concentration to 26% as in Example 17, but the fluidity was improved. However, it was difficult to feed the stock solution and spinning was impossible (Comparative Example 4). Therefore, the concentration was lowered to 16% and readjusted to obtain a spinning dope (Comparative Example 5). This spinning dope has a viscosity at 40 ° C. of 280 dPa · sec and a non-Newtonian index of 0.4 obtained by diluting the concentration to 15%.
It was 4. This 16% spinning dope was spun through a spinning nozzle (pore size 0.20 mm, number of pores 200) into a coagulation bath consisting of 10% acetone water at 10 ° C. under the same spinning bath conditions as in Example 17. In the sprinkling, the peeling property of the spinning dope from the nozzle surface is poor, and the liquid content of the spinning tow is noticeably thick and brittle even when it is guided to the take-up roll. Therefore, the next bath, 25 ° C, consisting of 45% acetone water Even if it is guided to 2.7 times and stretched by 2.7 times, stable spinning property and yarn running property due to frequent occurrence of yarn breakage and winding on a roll were not obtained, and material handling property in manufacturing was poor, and Example 17 It was not possible to obtain a final fiber that has undergone the drying, drawing and relaxation treatment steps as obtained in Step 1.

[0029]

INDUSTRIAL APPLICABILITY The spinning solution of the present invention is a solution of a sulfonic acid group-containing vinyl monomer in an acetone solution of an acrylic copolymer obtained by polymerizing acrylonitrile, vinyl chloride and a vinyl monomer containing a sulfonic acid group as main components. Despite the thickening phenomenon which becomes remarkable as the copolymerization ratio of the monomer increases, it is a low-viscosity spinning dope, so that it can be handled with a high spinning dope concentration. Especially in wet spinning,
Not only can it reduce draw breaks and winding problems in the fiber manufacturing process, which is a drawback of spinning tows that have a coarse coagulation structure that tends to occur when the concentration of the spinning dope is low, it also improves the physical properties by densifying the fiber, and sulfonic acid. The production of fibers having an increased group content will be facilitated, and the production of fibers excellent in dyeability improvement can be expected.

Claims (5)

[Claims] 1. A spinning dope containing the following components (A), (B) and (C), wherein the amount of the component (B) is 0 relative to 100 parts by weight of the component (A). .1 to 100
At 40 ° C. when the content of the component (A) is 15 parts by weight when the total amount of the components (A), (B) and (C) is 100% by weight. Non-Newtonian index is 0.6 to 1.0, a spinning dope: (A) acrylonitrile in which the composition ratio of the sulfonic acid group-containing vinyl monomer is 1 to 3% by weight,
And an acrylic copolymer whose main component is vinyl chloride,
(B) Viscosity improver, (C) Acetone. 2. The spinning dope according to claim 1, wherein the viscosity improver as the component (B) is an organic compound having active hydrogen or / and a polar group. 3. The spinning dope according to claim 2, wherein the organic compound having active hydrogen and / or a polar group is an organic acid salt. 4. The spinning dope according to claim 1, wherein the viscosity improver which is the component (B) is an inorganic salt. 5. A fiber obtained by wet spinning the spinning dope of claim 1.