JP2885474B2 - Stereoregular acrylonitrile polymer and composition for molding stereoregular acrylonitrile polymer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a stereoregular acrylonitrile polymer excellent in moldability such as fiberization or film formation, and a composition thereof.

This stereoregular acrylonitrile polymer is a material that is expected to be used as a fiber material with excellent mechanical strength and heat resistance in wet conditions, as a material for selective adsorption of metals, as a conductive polymer, or as a raw material for high-strength carbon fibers. is there.

[Conventional technology]

Conventionally, acrylonitrile polymers are excellent in bulkiness, texture, heat retention, etc. when molded into fibers, and can be dyed in vivid colors by introducing a copolymer component, and also excellent in dyeing weather resistance It is widely used for clothing because it has such physical properties.

The acrylonitrile polymer is usually produced by polymerizing acrylonitrile using a radical polymerization initiator or an anionic polymerization initiator. However, the acrylonitrile polymer obtained by such a method has no regularity of the chemical structure according to the measurement by the nuclear magnetic resonance method (hereinafter abbreviated as NMR). When this polymer is dissolved in a solvent and formed into a fiber or film, the crystallinity is lowered, and the mechanical properties are not sufficiently satisfactory. Inferior. In particular, when formed into fibers, the dimensional stability, tensile strength, elastic modulus, etc. are insufficient, which limits the application to high-grade garments such as high-grade fabrics, as well as industrial materials and space. At present, development of applications in the engineering field and the like is also restricted.

On the other hand, it is known that when an urea-acrylonitrile inclusion compound is irradiated with an actinic ray such as γ-ray, an acrylonitrile polymer having stereoregularity, that is, a so-called highly stereoregular acrylonitrile polymer is obtained. An acrylonitrile polymer having an isotactic triad fraction I (described later) of 0.4 or more obtained by this method has been found to have an improved melting point in the presence of water, and its fiber has a Young's modulus in hot water. Compared to conventional polyacrylonitrile fibers, they have the characteristics of being significantly improved and having improved heat resistance in a wet state. Also, when a metal salt such as copper sulfate is added to the acrylonitrile polymer solution,
Since metal ions are selectively coordinated at the meso position with respect to the cyano group of the acrylonitrile polymer molecule [“Polymer Journal”, Vol. 18, p. 277 (1986)], the material for selective adsorption of metal and conductivity It is also suitable as a polymer material. Further, it is a material expected as a raw material for high-strength carbon fiber due to its high crystallinity.

In the above method of irradiating the urea-acrylonitrile clathrate compound with γ-rays to obtain a highly stereoregular acrylonitrile polymer (hereinafter referred to as γ-ray method), the isotactic triad fraction I is 0.4 to 0.8. High values up to the extent are obtained, and the various characteristics described above are sufficiently obtained. However, when this polymer is formed into a film or fiber, it has been difficult to produce a film or fiber having a sufficiently high performance due to poor molding characteristics, particularly poor stretchability.

[Problems to be solved by the invention]

An object of the present invention is to improve the moldability of such a conventional high stereoregularity acrylonitrile polymer, and to provide a highly isotactic acrylonitrile polymer having good stretchability.
And a molding composition containing such an acrylonitrile polymer.

[Means for Solving the Problem (1)] The present inventors have repeated studies on catalyzed polymerization of acrylonitrile regardless of the above-mentioned γ-ray method, and have boldly studied the boiling point of acrylonitrile at atmospheric pressure (that is, 77 ° C.). ) Was carried out at a higher temperature than that of acrylonitrile.
As a result, surprisingly, under these special conditions, an acrylonitrile polymer having an isotactic fraction higher than 0.4 is obtained, and the composition obtained from this polymer using a suitable solvent or plasticizer. The product was found to exhibit good moldability such as good stretchability when spun or formed into a film [JP-A-1-203406].

Furthermore, the present inventors have studied in detail the difference in physical properties between a stereoregular acrylonitrile polymer obtained by a conventional γ-ray method and a stereoregular acrylonitrile polymer produced by, for example, the above-described catalytic method. As a result, it was found that the acrylonitrile polymer having good moldability such as stretchability had a relation of I + 3S> 0.95 between the triad fractions I and S (described later).

Further, the present inventors have established a relationship of I + 3S <0.95 for the stereoregular acrylonitrile polymer obtained by the γ-ray method, and the polymer obtained by the catalytic method is in a region related to I and S. And found that
The present invention has been completed.

That is, the present invention relates to a linear acrylonitrile polymer having a viscosity average molecular weight of 50,000 or more, and its isotactic triad fraction I and syndiotactic
A stereoregular acrylonitrile polymer is provided, wherein the triad fraction S satisfies the following formulas: I> 0.4 and I + 3S> 0.95.

The stereoregular acrylonitrile polymer of the present invention is formed into a composition containing water, a protic acid or an aqueous solution thereof as defined below, an aqueous solution of an inorganic salt, or a mixture of an organic solvent and an inorganic salt as a solvent or a plasticizer. Provided.

(Operation)

In the past, there have been few studies on acrylonitrile polymers having a value of (I + 3S) of more than 0.95 as in the present invention, and they have been reported only slightly [[European Polymer Journal, No. 22].
Vol., P. 559 (1986)] to the extent known is a method of polymerizing acrylonitrile in a polar or inorganic solvent using a complex of an alkoxide and an alkali metal amide compound as a polymerization initiator.
However, the acrylonitrile polymer is (I + 3
Although the value of S) was larger than 0.95, the value of I was as small as 0.2 to 0.4, and did not have excellent properties such as mechanical strength and heat resistance in a wet state of the stereoregular acrylonitrile polymer.

Although the reason why the difference in moldability occurs at the value of (I + 3S) shown in the above formula is not limited, the triad fraction I, H, S (described later) of the stereoregular polymer is expressed. A straight line qi connecting a completely isotactic point i and a completely stereoregular point q in the triangular diagram (FIG. 1).
It is presumed that there is some relation with that is expressed by I + 3S = 1.

Briefly explaining FIG. 1, i is a completely isotactic point, s is a completely syndiotactic point, and h is a heterotactic limit. Further, q is a position when the stereoregularity is completely lost and the stereoscopic configuration is completely random. x is any point in the triangular diagram, and corresponding to that point I (ie, isotactic triad fraction mm), H (ie, heterotactic triad fraction mr), S (ie, The magnitude of the syndiotactic triad fraction rr) is xi, xh,
It has the length indicated by xs.

The isotactic triad fraction I mentioned here is one of the so-called triad fractions, and is a ¹³ C-NMR (mass number 13) of a solution dissolved in deuterated dimethyl sulfoxide.
Nuclear Magnetic Resonance Measurement Apparatus using a carbon isotope) of the cyano group. More specifically, it is determined by peak identification based on the assigned pentad tacticity according to the method described above described in Polymer Journal Vol. 17, p. 1291 (1985). That is, in the peak splitting chart based on the stereoregularity of nuclear magnetic resonance absorption of ¹³ C-NMR, the ratio of the sum of the intensities of the three peaks of mmmm, mmmr, and rmmr to the total peak intensity is the isotactic fraction.

Similarly, for other triad fractions, the heterotactic triad fraction H is defined as the ratio of the sum of the intensities of the four peaks of mmrm, mmrr, rmrm, rmrr, and the syndiotactic triad fraction S is It is defined as the ratio of the sum of the intensities of the three peaks of mrrm, mrr, and rrrr. Therefore, the following equation holds.

I + H + S = 1 In this measurement, in order to increase the resolution and to give a quantitative property, in particular, the absorption peak region of carbon in the cyano group (119
121121 ppm; based on tetramethylsilane), and observe ± 500 Hz around the peak. A Fourier transform NMR (FX-200) manufactured by JEOL Ltd. is used as an apparatus, deuterated dimethyl sulfoxide is used as a solvent, and the sample concentration is adjusted to 3 to 20% by weight. Measurement conditions are as follows: temperature 80 ° C, observation frequency width 1000 Hz, data point
16k, irradiation time 6.5μs (45 ° pulse), pulse delay time
2.5s, sampling time 8.1s, total number of times 64 × 10 to 64 × 10
Set to 0.

[Means for Solving the Problem (2)] The molecular weight of the stereoregular acrylonitrile polymer of the present invention is not particularly limited in general. And have a viscosity average molecular weight of 50,000 or more.

The stereoregular acrylonitrile polymer of the present invention is an acrylonitrile homopolymer. The stereoregular acrylonitrile polymer of the present invention can be produced by a method of polymerizing acrylonitrile using an organometallic compound as an initiator as described below.

That is, an organic metal compound containing an alkaline earth metal, an organic metal compound called an art complex in which two or more metals of Groups I, II and III of the periodic table are combined, and further containing an alkaline earth metal A so-called Ziegler-Natta type initiator system using a combination of an organometallic compound and a transition metal compound is used.

The following are examples of organometallic compounds that can be suitable initiators, but the polymer of the present invention is not limited by these examples.

First, examples of the organometallic compound containing an alkaline earth metal include organometallic compounds containing beryllium, magnesium, calcium, strontium, and barium. Among these, the organic beryllium compounds represented by the formula R ₂ Be include diethyl beryllium, normal propyl beryllium, normal butyl ethyl beryllium, and the like, and the Grignard type represented by the formula RBeX includes phenyl. Examples include beryllium chloride and allyl beryllium bromide. Calcium compounds include formulas such as diphenyl calcium and phenylethyl calcium
There are those represented by R ₂ Ca and those represented by the formula RCaX such as ethyl calcium bromide and normal butyl calcium iodide. Examples of the strontium compound include diethyl strontium, and examples of the barium compound include dinormal propyl barium.

As the organomagnesium compound, for example, the formula R ₂ Mg
(R is a hydrocarbon group comprising an aliphatic or aromatic hydrocarbon or a combination thereof), dimethylmagnesium, diethylmagnesium, dinormalpropylmagnesium, dinormalbutylmagnesium, diisoamylmagnesium, dinormalhexylmagnesium,
Organic magnesium compounds having two identical hydrocarbon groups such as diallyl magnesium and diphenyl magnesium,
And organomagnesium compounds having two different hydrocarbon groups, such as methylethylmagnesium, normal butylethylmagnesium, and phenylethylmagnesium. Furthermore, the so-called Grignard reagent RMgX
(R is the same as above and X is a halogen) are also effective as initiators. This includes ethyl magnesium chloride, normal butyl magnesium bromide, phenyl magnesium iodide, benzyl magnesium fluoride and the like.

Furthermore, organomagnesium compounds in which these alkyl groups are replaced with amino groups, alkoxy groups, alkylsilyl groups, alkylthio groups, and their combined substituents also exhibit higher effects. For example, a compound represented by the formula R ₂ NMgr such as ethyl diethylamino magnesium, and bis (diethylamino) magnesium, bis formula R ₂ NMgNR _2, such as (diphenylamino) magnesium
(R in these two formulas is the same as described above, except that two Rs represented by R ₂ are bonded to each other and form a heterocyclic ring together with the nitrogen atom to which they are bonded. A compound represented by the formula ROMgR such as methoxyethylmagnesium (R is the same as described above); a formula ROMgOR such as dimethoxymagnesium, diethoxymagnesium, dinormal maltoxymagnesium (R is the same as described above) A compound represented by the formula: bis (trimethylsilyl)
Formula R ₃ SiMgSiR ₃ like magnesium (R is as above)
A compound represented by the formula R ₃ SiMgR such as trimethylsilylethylmagnesium (R is as defined above); a formula RSMgR such as methylthioethylmagnesium
(R is the same as described above); a compound represented by the formula RSMgSR such as bis (methylthio) magnesium (R is the same as described above)
And a formula (R ₃ Si) ₂ NMgN such as bis [bis (trimethylsilylamino)] magnesium
Compound represented by (SiR ₃ ) ₂ and formula (R ₃ Si) ₂ NMgR
(Wherein R in both formulas is the same as described above).

It is also possible to use a transition metal compound in combination with these organometallic compounds. The transition metal compound is a part of a raw material of a polymerization initiator usually called a Ziegler-Natta catalyst, and mainly includes dichlorotitanium, trichlorotitanium, tetrachlorotitanium, tetranormal propoxy titanium,
There are titanium compounds represented by tetrahydroxytitanium, dicyclopentadienyldichlorotitanium and the like, vanadium compounds such as trichlorovanadium, tetrachlorovanadium, oxytrichloride vanadium and acetylacetone vanadium, and many other compounds such as trichlorochromium.

Examples of so-called art complexes combining two or more metals of Groups I, II and III of the Periodic Table include:
The following general formulas can be given in a general form. That is, M ¹ M ² R _3-n H _n , M ¹ AlR _4-n H _n , M ² Al
R _5-n X _n , M ² (AlR _4-n H _n ) ₂ , M ² AlR _5-n (NR ₂ ) _n , LiZnR
_{3-n (NR 2) n} , and _{Li 2 ZnR 4-n (NR} 2) is _n.

Here, R in the formula may be the same or different, and is a hydrocarbon composed of an aliphatic or aromatic hydrocarbon or a combination thereof. M ¹ is a kind of metal selected from lithium, sodium and potassium, M ² is a kind of metal selected from magnesium, beryllium, calcium, zinc and cadmium, X is fluorine, chlorine, bromine, N is a kind of element selected from iodine, and n is zero or a positive integer and 5 in the same molecule.
It is assumed that the subscript of -n, 4-n or 3-n takes a value in a range where the subscript does not become negative.

Examples of these compounds include triethylsodium magnesium, bis (tetraethylaluminum) magnesium, diphenylaminotetraethylmagnesiumaluminum, diphenylaminodiethylzinclithium, dinormalbutyldiethylzincdilithium, and the like.

Next, the polymerization conditions will be described. The polymerization temperature needs to be 110 ° C. or higher. When acrylonitrile is polymerized below the boiling point at atmospheric pressure (77 ° C.), the formula I> 0.4
Is not satisfied, and the viscosity average molecular weight is also lower than 50,000. This is either a substantial low molecular weight, or even if the molecular weight is not low, the branched structure increases in the polymer chain and is no longer linear, and the yellow color of the polymer The coloring is also extremely marked. When polymerized at 77 ° C or higher and lower than 110 ° C, Formula I> 0.4 and Formula I + 3S> 0.9
5 is satisfactory, but the viscosity average molecular weight is still less than 50,000.

FIG. 2 shows a polymer obtained by polymerization at a polymerization temperature of 85 ° C. (viscosity average molecular weight: 5,000) [FIG. 2 (a)] and a polymer obtained by polymerization at a polymerization temperature of 130 ° C. (viscosity average molecular weight: 88,000) ) [Second
2 (b)] shows an NMR chart. The two charts in FIG. 2 (a) have a larger number of absorption peaks than the two charts in FIG. 2 (b) (that is, the peaks indicated by arrows are seen only in FIG. 2 (a), In FIG. 2 (b), a large number of peaks, which are considered to be attributable to less than a molecule or to branching in the case of a small molecule, are observed. [A dissertation on the branching of polyacrylonitrile; W. Berger et al .: A
cta Polymerica, 33 , 626, 632 (1982), etc.]. In any case, in this case, the spinnability and stretchability are extremely poor, and the physical properties of the molded product are inferior.

Regarding the upper limit of the polymerization temperature, it is generally known that PAN is decomposed and colored at a temperature slightly lower than 200 ° C., and it is practically desirable to carry out the polymerization at a temperature lower than the temperature at which the PAN is decomposed and colored.

The polymerization solvent is not difficult to select as long as it does not inhibit the polymerization ability of the above-mentioned initiator among various organic solvents, but a more preferable solvent contains an aromatic hydrocarbon group in its own molecule. Organic solvent. Although the mechanism of polymerization using such a solvent is not yet fully understood, the aromatic π electrons in the solvent molecule play some important role in the formation of the stereoregularity of the acrylonitrile polymer. It is considered something. The solvent used is not limited, but examples of these solvents include benzene, toluene, ortho-xylene, meta-xylene, para-xylene, naphthalene, diphenyl ether, biphenyl and the like.

As the solvent used for molding the stereoregular acrylonitrile polymer of the present invention, many solvents known for ordinary acrylonitrile polymers cannot be used because they do not necessarily dissolve the polymer.
Solvents that can be used for the acrylonitrile polymer having high stereoregularity are limited to water; protonic acids or aqueous solutions, aqueous solutions of inorganic salts, or organic solvents containing inorganic salts. What is called an acid has definitions and categories from various standpoints, such as an acid defined by Bronsted and an acid having the meaning of Lewis, but a protonic acid here refers to an acid having a proton in the molecule. Say. Examples of protic acids include nitric acid, sulfuric acid, various phosphoric acids, hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, inorganic acids such as perchloric acid, acetic acid, dichloroacetic acid, Various organic acids such as trichloroacetic acid and trifluoroacetic acid are exemplified. In addition, phenols and alcohols are naturally included in the protonic acid. According to the study of the present inventors, in a closed system, phenols and alcohols dissolve the polymer of the present invention under a condition of a certain temperature or higher corresponding to each compound under a condition exceeding 180 degrees Celsius in water. Have found.

Further, an aqueous solution of an inorganic salt can be used as a solvent or a plasticizer for the polymer of the present invention. Examples of the preferred inorganic salts to be used include various rhodanates such as sodium rhodanate, lithium rhodanate, calcium rhodanate, zinc rhodanate, various halogen-containing salts including zinc chloride and zinc fluoride, and perchlorine. And perchlorates such as sodium acid, calcium perchlorate, barium perchlorate, and aluminum perchlorate.

Further, an organic solvent containing inorganic salts is also used. An organic solvent to which no inorganic salts are added does not dissolve the polymer at all, or swells to an extent that dissolution is extremely difficult. Examples of the organic solvent used include dimethylformamide, dimethylsulfoxide, dimethylacetamide, succinonitrile, γ-butyrolactone, an aqueous solution of ethylene carbonate, and hydroxyacetonitrile. As the inorganic salt to be added, for example,
Lithium chloride, lithium fluoride and the like are preferably used.

The proportion of the stereoregular acrylonitrile polymer and the various solvents in the composition comprising the various solvents varies depending on the type of the solvent and the molding method of the composition, but generally, the acrylonitrile polymer is 5 to 50% by weight based on the composition weight. %, Solvent 50 ~
It is preferable to select each from the range of 95% by weight.

The fiberization of the stereoregular acrylonitrile polymer of the present invention can be carried out by a dry and wet spinning method after forming a spinning solution using the above-mentioned solvent in the same manner as in the conventional fiberization of an acrylonitrile polymer. As a typical example, when a nitric acid aqueous solution is used as a solvent, 10 to 40 parts by weight of a polymer is dissolved in 100 parts by weight of a nitric acid aqueous solution having a concentration of 60 to 80% by weight to prepare a spinning solution. The spinning solution is extruded from a spinneret into a coagulation bath composed of a 20 to 50% by weight nitric acid aqueous solution, and coagulated into fibers. The fibers are washed with water, stretched about 10 times in hot water at 90 ° C., and then dried. The dried fiber can be used as it is, but can be subjected to redrawing, heat treatment in a wet state or a dry state as necessary.

Fibers obtained by fibrillating the stereoregular acrylonitrile polymer of the present invention have excellent workability, particularly excellent stretchability, for example, the value of the maximum stretch ratio in hot water of 90 ° C. which is usually higher than 10 times, depending on the conditions. Some are more than 11 times. On the other hand, when the acrylonitrile polymer is fiberized by the conventional γ-ray method, the maximum draw ratio in hot water at 90 ° C. is preferably at most about 9 times even if the conditions are selected.

The fiber drawn in the above hot water can be further drawn at a temperature of 120 ° C or higher in an organic heat medium or on a hot roll in a dry process, thereby significantly improving the mechanical properties of the fiber in a wet state. Can be done. The mechanical properties in the wet state are usually evaluated by Young's modulus in hot water at 95 ° C., which is 1 g / d or less for ordinary acrylonitrile fibers, and 3 to 5 g / d for improved ones. However, the fiber using the stereoregular acrylonitrile polymer of the present invention has a weight of 15 g / d or more.

〔The invention's effect〕

The stereoregular acrylonitrile polymer of the present invention has high crystallinity such as an increase in melting point in the presence of water as described above,
When formed into fibers, those having excellent mechanical strength and heat resistance in a wet state can be obtained, and also excellent in stretchability and other workability in a fiberizing step.

Further, a composition of a stereoregular acrylonitrile polymer containing a protonic acid or an aqueous solution thereof, an aqueous solution of an inorganic salt or a mixture of an organic solvent and an inorganic salt as a solvent or a plasticizer can sufficiently exhibit the excellent properties of the polymer. It is useful for forming fibers and films that have been exhibited.

〔Example〕

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

Example 1 Polymerization was carried out by using an apparatus as shown in FIG. 3 which was set up so that evaporated components could be condensed and refluxed. First 10
Nitrogen was introduced into the three-necked flask 5 through a nitrogen supply pipe 8 to replace air, and the nitrogen was introduced under a nitrogen stream to 1,2,3,5.
8 were charged with tetramethylbenzene. The temperature was adjusted to 130 ° C. by adding 120 ml of a 1.0 molar solution of dinormal hexylmagnesium in heptane as a polymerization initiator. Next, one drop of acrylonitrile was polymerized for 60 minutes.

To this, an appropriate amount of a mixed solution of methanol and hydrochloric acid was added to terminate the polymerization reaction. Thereafter, filtration and washing were repeated, followed by drying and weighing. As a result, 238 g of a polymer was obtained.

When this polymer was dissolved in deuterated dimethyl sulfoxide at 5% by weight and ¹³ C-NMR measurement was performed, I, H and S were 0.576, 0.282 and 0.142, respectively. Therefore, (I + 3
S) becomes 1.002. Its viscosity average molecular weight was 95,000.

Here, the viscosity average molecular weight is measured at 25 ° C. by dissolving the polymer to be measured in dimethyl sulfoxide, determining the intrinsic viscosity [η] by a conventional method, and then calculating the viscosity average molecular weight M by the following formula.
Was calculated.

[Η] = 0.204 × M ^{0.58 In} an environment where 200 g of this polymer was kept at 0 ° C.,
When dissolved in a 70% by weight aqueous nitric acid solution at a concentration of 16% by weight, the composition exhibited spinnability suitable for spinning. This spinning dope was added to a coagulating liquid consisting of a 34% by weight nitric acid aqueous solution to obtain a pore size of 0.
It was discharged from a 3 mm, 100-hole spinneret, solidified, and washed with water to obtain an undrawn yarn. Then, when the maximum draw ratio of this undrawn yarn was measured in hot water at 90 ° C., it was 10.5 times. Furthermore, at a temperature of 135 ° C. on four dry heat rolls, using a drawn yarn that has been drawn at 95% of the maximum draw ratio in hot water.
Stretching was performed 2.0 times. The strength of the obtained fiber was 18.2 g / d, and the Young's modulus measured in hot water at 95 ° C. was 17.2 g / d.

Example 2 A stereoregular acrylonitrile polymer was obtained in the same manner as in Example 1 except that normal butylethylmagnesium was used as the polymerization initiator, and this polymer was spun into fibers. When the maximum stretching ratio of the undrawn yarn was measured, it was 11.3 times. After drawing at 95% of the maximum draw ratio, the fiber obtained by dry drawing under the same conditions as in Example 1 had a strength of 14.5 g / d, and the Young's modulus measured in hot water at 95 ° C was It was 16.0 g / d.

Example 3 A stereoregular acrylonitrile polymer was obtained in the same manner as in Example 1 except that diethyl beryllium was used as a polymerization initiator, and this polymer was dissolved in dimethylformamide containing 5% by weight of lithium chloride. The mixture was discharged into a weight% coagulation bath and washed with water. When the maximum draw ratio was measured in the same manner as in Example 1, it was 10.2 times. After drawing at 95% of the maximum draw ratio, the fiber obtained by dry heat drawing under the same conditions as in Example 1 had a strength of 12.4 g / d and a Young's modulus of 15.4 g at 95 ° C in hot water. / d.

Example 4 A stereoregular acrylonitrile polymer prepared in the same manner as in Example 1 was dissolved in a 50% by weight aqueous solution of sodium rhodanate and discharged into a coagulation bath of a 12% by weight aqueous solution of sodium rhodanate, followed by washing with water. When the maximum draw ratio was measured in the same manner as in Example 1, it was 10.2 times. After drawing at 95% of the maximum draw ratio, the fiber obtained by dry drawing under the same conditions as in Example 1 had a strength of 12.4 g / d.
The Young's modulus of the hot water at 1 ° C was 15.4 g / d.

Comparative Example 1 Normal butyl mercaptan was added to 56 g of acrylonitrile at a molar ratio of 1: 1.5 by adding 2 / 1,000 mol of normal butyl mercaptan to acrylonitrile at a molar ratio of 1: 1.5 to a 2-volume dewar bottle. A total of ten pieces were placed, mixed and sealed, and allowed to stand for 6 days while cooling to −78 ° C. using dry ice. Next, at -78 ° C
Gamma rays of 10,000 Curie were irradiated for 170 minutes at an irradiation dose rate of 1.6 × 10 ⁵ x-rays / hour. The reaction was then washed with warm water and methanol to completely remove urea. The total weight of the obtained acrylonitrile polymer was 550 g, and its stereoregularity and molecular weight were measured in the same manner as in Example 1. As a result, I, H, and S were 0.553, 0.334, and 0.113, respectively. Therefore, (I + 3S) is 0.892. The viscosity average molecular weight was 203,000.

200 g of this polymer was added to 70% by weight
Dissolve in a nitric acid aqueous solution at a concentration of 16% by weight, and spin the undiluted spinning solution
An undrawn yarn was obtained by spinning in a coagulation solution composed of a 34% by weight aqueous nitric acid solution using a spinneret having the same specifications. 90 of this undrawn yarn
The maximum stretching ratio in hot water at ℃ was 8.1 times. After drawing at 95% of the maximum draw ratio, the fiber obtained by dry drawing under the same conditions as in Example 1 has a strength of 6.6 g / d, and the Young's modulus measured in hot water at 95 ° C is It was 13.7 g / d.

Comparative Example 2 Normal butyl mercaptan compared to acrylonitrile
A stereoregular acrylonitrile polymer was obtained in exactly the same manner as in Comparative Example 1 except that 4 / 1,000 mol was added, and this polymer was converted into a fiber by the same spinning method as in Example 3. Maximum draw ratio in hot water at 9.5 ℃
It was twice. After stretching 95% of the maximum stretching ratio,
The strength of the fiber obtained by dry drawing under the same conditions as in Example 1 was
7.8 g / d, and the Young's modulus measured in hot water at 95 ° C is 14.5 g / d.
d.

Comparative Example 3 Using xylene as a polymerization solvent, the polymerization temperature was set to 100 ° C.
A stereoregular acrylonitrile polymer was obtained in the same manner as in Example 1, except that the polymer was spun into fibers. The viscosity average molecular weight of the polymer was 26,000. When the maximum draw ratio of the undrawn yarn was measured,
It was 4.7 times. After drawing at 95% of the maximum draw ratio, the fiber obtained by dry drawing under the same conditions as in Example 1 had a strength of 1.5 g / d, and the Young's modulus measured in hot water at 95 ° C was 1.5 g / d. 2.
It was 9 g / d.

Comparative Example 4 Polymerization was carried out at a polymerization temperature of 0 ° C. using toluene as a polymerization solvent and normal butyl lithium as a polymerization initiator. The viscosity average molecular weight of the obtained polymer was 53,000. The polymer was spun under the same conditions as in Example 1 to obtain fibers. When the maximum drawing ratio of the undrawn yarn was measured, it was 10.7 times. After drawing at 95% of the maximum draw ratio, the fiber obtained by dry drawing under the same conditions as in Example 1 has a strength of 2.3 g / d, and the Young's modulus measured in hot water at 95 ° C is 2.3 g / d.
It was 4.8 g / d.

Examples 5 to 7 Polymerization and fiberization were carried out in the same manner as in Example 1 except that the polymerization initiator, the polymerization solvent and the polymerization temperature were changed as shown in Table 1.

Table 1 summarizes the detailed results including the above Examples and Comparative Examples. Here, all the examples relate to a stereoregular acrylonitrile polymer obtained by a catalytic method, and comparative examples relate to an acrylonitrile polymer obtained by a γ-ray method and a catalytic method outside the scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a triangular diagram expressing the triad fractions I, H, S of a stereoregular acrylonitrile polymer. FIG. 2 is a chart of ¹³ C-NMR. FIG. 2 (a) shows absorption of a polymer having a viscosity average molecular weight of 5,000, and FIG. 2 (b) shows absorption of a polymer having a viscosity average molecular weight of 88,000. FIG. 3 shows an example of a polymerization apparatus used for producing a stereoregular acrylonitrile polymer. The reference numerals in FIG. 3 are as follows. DESCRIPTION OF SYMBOLS 1 ... Magnetic rotator, 2 ... Insulation material, 3 ... Magnetic rotator, 4 ... Temperature adjustable oil bath, 5 ... Three-necked flask, 6 ... Drip funnel, 7 ... Cooling tube, 8 ... nitrogen supply pipe, 9 ... exhaust pipe, 10 ... liquid paraffin bath.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-277413 (JP, A) JP-A-62-282016 (JP, A) JP-A-63-304029 (JP, A) JP-A 64-64 79206 (JP, A) JP-A-1-203406 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08F 20 / 44,120 / 44,220 / 44 C08L 33/22 D01F 6/18, 9/22

Claims (2)

(57) [Claims] 1. A linear acrylonitrile polymer having a viscosity-average molecular weight of 50,000 or more, characterized in that its isotactic triad fraction I and syndiotactic triad fraction S satisfy the following formula: Stereoregular acrylonitrile polymer. 1> 0.4 and I + 3S> 0.95 2. The composition according to claim 1, comprising a stereoregular acrylonitrile polymer according to claim 1 and water, a protonic acid or an aqueous solution thereof, an aqueous solution of an inorganic salt, or a mixture of an organic solvent and an inorganic salt as a solvent or a plasticizer. A stereoregular acrylonitrile polymer molding composition, wherein the polymer is contained in an amount of 5% by weight or more and 50% by weight or less.