JPS617332A - Production of high molecular weight polyarylene sulfide - Google Patents

Abstract

PURPOSE:To obtain a polyarylene sulfide having high molecular weight, economically, by reacting an alkali metal sulfide with a dihalo-aromatic compound in two steps, and drastically changing the amount of existing water and the polymerization temperature between the former polymerization stage and the latter polymerization stage. CONSTITUTION:1mol of an alkali metal sulfide (e.g. lithium sulfide) and 0.9- 1.1mol of a dihaloaromatic compound (e.g. p-dichlorobenzene) are polymerized in an organic amide solvent (e.g. N-methylpyrrolidone) in the presence of 0.5- 2.4mol of water at 180-235 deg.C until the conversion of the dihaloaromatic compound reaches 50-98mol%. A polyarylene sulfide having a melt-viscosity of 5- 300 poise can be produced by this process. Water is added to the polymerization slurry to attain a water-content of 2.5-7mol per 1mol of the alikali metal sulfide, and the polymerization is continued by raising the temperature of the system to 245-290 deg.C to obtain a polyarylene sulfide having a melt-viscosity of >=1,000 poise.

Description

BACKGROUND OF THE INVENTION Technical Field The present invention relates to a method for producing high molecular weight polyarylene sulfide (hereinafter referred to as PAS). More specifically, the present invention provides PAs having a key feature in the manner in which the reaction between an alkali metal sulfide and a Ciba aromatic compound is carried out.
This invention relates to a method for producing S.

In recent years, there has been an increasing demand for thermoplastic resins with higher heat resistance for use in electronic equipment components, automobile parts, and the like.

PAS also has properties as a resin that can meet these demands, but
Since it is difficult to obtain AS with a sufficiently high molecular weight, it is extremely difficult to mold it into films, sheets, fibers, etc., and the molded products are extremely brittle, which is a major problem. was there.

The present invention aims to solve these problems by providing a method for producing PAS with a significantly high molecular weight at low cost.

Conventional technology A typical method for producing PAS is a method in which a dihaloaromatic compound and sodium sulfide are reacted in an organic amide solvent such as N-methylpyrrolidone.
It is disclosed in the TE publication. However, PAS produced by this method has a low molecular weight and low melt viscosity, making it difficult to mold it into films, sheets, fibers, and the like.

From this point of view, in order to obtain PAS with a high degree of polymerization, various methods have been proposed that are improved from the above methods. The most representative Tokko Akira! ;2-/cocop.

In the method described in the above publication, an alkali metal carboxylate is used as a polymerization aid in the reaction system. According to this method, the amount of polymerization aid added is required to be approximately equimolar to the alkali metal sulfide.
In order to obtain PAS, it is necessary to use large amounts of expensive lithium acetate and sodium benzoate among various polymerization aids, which results in an increase in the production cost of PAS, which is industrially disadvantageous. It seems that it will be. In addition, with this method, there is a risk that a large amount of organic acids, etc. will be mixed into the treated wastewater when PAS is recovered after the polymerization reaction, causing a pollution problem, and it will cost a lot of money to prevent this. There seems to be a major problem from an economic standpoint, such as the need for

If the melt viscosity or molecular weight is simply high, then
A method of introducing a crosslinked structure by mildly oxidizing PAR may be used. However, the high molecular weight PAS obtained by this method
Since there is no linearity, the stringability and film forming properties are poor.

SUMMARY OF THE INVENTION In view of the above points, the present inventors have developed a method for manufacturing linear PAR with high melt viscosity at low cost without using a polymerization aid such as an alkali metal carboxylate. As a result of a detailed study of the polymerization mechanism in a simple polymerization system of an alkali metal sulfide and a dihaloaromatic compound, we found that among the various polymerization conditions, the amount of coexisting water and the polymerization temperature are particularly significant in the pre-polymerization stage and the post-polymerization stage. The present invention was achieved by unexpectedly discovering that it is possible to produce PAS with a significantly high molecular weight without using any auxiliaries by varying the .

That is, the productivity of polyarylene sulfide having a melt viscosity of too boys or more according to the present invention is achieved by reacting an alkali metal sulfide and a dihaloaromatic compound in an organic amide solvent to obtain a polyarylene sulfide. The method is characterized in that it is carried out in at least the following two steps.

(1) Alkali metal sulfide, z-2.
The reaction is carried out in the presence of about mol of water at a temperature of /II to Jj'C, and the melt viscosity is ! Conversion rate S of polyarylene sulfide with ~300 voids to dihaloaromatic compound
A step of producing it with O~rij morch, (2) 1 mole of alkali metal sulfide,! Adding water so that ~7.0 liters of water is present, raising the temperature to 2 pt-0°C, and continuing the above reaction.

Effects In the present invention, water is added after the first stage polymerization, and the temperature is raised to perform the second stage polymerization at a predetermined water content and temperature. PAS with high melt viscosity of
It was successfully obtained. Since this method is extremely simple and does not require any special auxiliary agents, the above-mentioned problems caused by the use of auxiliary agents do not exist, and it is also economical. Since the obtained PAR has a high melt viscosity and is linear, not only general molded products but also excellent fiber films can be obtained.

Furthermore, according to the present invention, since the PAS is obtained in the form of granules after polymerization, post-treatments such as separation and washing are easy, and there is also the advantage that a pelletizing step is not necessary as a resin material. That is, another feature of the present invention is that pearl-like PARs can be obtained. Even with the method of the present invention, non-spherical PARs may be obtained if the stirring conditions are not appropriate. In many cases, the obtained PAS is a linear shape that is close to a perfect sphere and has a very uniform particle size. When we investigated the state in which pearl-like PAS was formed, we surprisingly found that PAS was not granulated during the process of cooling the reaction system after the completion of the post-polymerization, but rather that the PAS was molten at a relatively early stage of the post-polymerization. It was found that the particles were granulated into pearls, and as the reaction progressed within the particles and the melt viscosity increased, the particles hardened to the extent that they did not fuse together. Such knowledge is thought to have been previously unknown.

Until now, in the polymerization of PAR, it has been believed that the presence of a large amount of water in the polymerization system causes undesirable hydrolysis reactions, and efforts have been made to reduce the amount of coexisting water in the system. . Usually, in order to obtain a PAR with a high melt viscosity, the amount of coexisting water is limited to 1 mol to λ mol per 1 mol of alkali metal sulfide. As in the method of the present invention, a method in which a large amount of water is added during polymerization at a stage when the melt viscosity of the produced PAS is extremely low, and the polymerization temperature is raised to further continue the polymerization has never been proposed. Considering the conventional thinking of those skilled in the art regarding coexisting water, the method of the present invention can be said to be truly revolutionary.

The method for producing PAS according to the invention consists in carrying out the reaction of an alkali metal sulfide with a dihaloaromatic compound under specific conditions.

Alkali Metal Sulfides The alkali metal sulfides used in the present invention include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide, and mixtures thereof. These alkali metal sulfides can be used as hydrates or aqueous mixtures or in anhydrous form.

Among these alkali metal sulfides, sodium sulfide is the cheapest and is industrially preferred.

In addition, in order to react with alkali metal type sulfides and alkali metal thiosulfates, which should exist in trace amounts in alkali metal sulfides, a small amount of alkali metal hydroxide is used in combination to remove these impurities or convert them into sulfides. It is possible to measure the conversion of

Dihaloaromatic compound The dihaloaromatic compound used in the present invention may include, for example, a dihaloaromatic compound as described in JP-A-39-222.2A.

In particular, P-cyclopenze/, m-dichlorobenzene,! - dikaltoluene, p-dibromobenzene,
/, 4! -Dicumylnaphthalene, l-methoxyco,!
-dichlorobenzene, dichlorobenzene, dichlorobiphenyl,
3. j-dichlorobenzoin 11, p,p'-dichlordiphenyl ether, J,J'-dichlordiphenyl sulfate!
/7p7, J, J'-dichlorodiphenyl sulfoxide s J, s'-dichlorodiphenyl and the like are preferred. Among these, those containing paradihalopense/, typified by p-dichlorobenzene, as a main component are preferred.

By appropriately selecting combinations of dihaloaromatic compounds, copolymers containing two or more different reactive units can be obtained. For example, products can be obtained by using a combination of p-dichlorobenzene and m-dicumylbenzene or PIp'-dichlorodiphenylsulfone.

The PAR according to the present invention is a polymer of the above-mentioned dihaloaromatic compound, but a monohalo compound (not necessarily an aromatic compound) may be used to form the terminal end of the resulting polymer or to control the polymerization reaction or molecular weight. It is also possible to use together a polyhalo compound (not necessarily an aromatic compound) having more than trihalo in order to form a branched or crosslinked polymer. Specific examples when these monohalo or polyhalo compounds are aromatic compounds will be obvious to those skilled in the art as mono- or polyhalo derivatives of the above specific examples. Physically,
For example, by using dichlorobenzene in combination with a small amount of trichlorobenzene, a branched phenylene sulfide polymer can be obtained. However, fiber
In order to obtain a film or the like, the PAS is preferably substantially linear and preferably has a low degree of branching.

Polymerization Solvent The organic amide solvent used in the polymerization reaction of the present invention includes N-methylpyrrolidone (NMP), N-ethylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylcaprolactam, and tetramethyl. Mention may be made of urea, hexamethyl phosphate triamide, etc., and mixtures thereof. Among these, N-methylpyrrolidone is particularly preferred. The organic amide used as the polymerization solvent is preferably an aprotic compound.

The amount of the organic amide solvent to be used is preferably in the range of Q, co to J liters per mole of alkali metal sulfide. It is carried out in at least two different stages. Here, "at least two steps" means that an auxiliary step may be added before, after, or in the middle of these two steps, as long as the effect of the present invention based on the combination of these two steps is achieved. It also means something good.

(2) First-stage polymerization Now, in the first step of the present invention, in other words, in the first-stage polymerization, 0.2 mol to λ per 1 mol of alkali metal sulfide
, a polymerization reaction system containing μmol of water at iro℃~23!
Polymerization is carried out at a temperature of "C" until the conversion rate of the dihaloaromatic compound in the polymerization reaction system becomes SO mole - t mole to obtain a PAS with a melt viscosity of ~300 voids (in the present invention, the melt viscosity is is 3i.

℃ and a shear rate of 200 seconds].

In carrying out the process, first, an alkali metal sulfide and a dihaloaromatic compound are added to an organic amide solvent at a temperature ranging from room temperature to 30°C, preferably under an inert gas atmosphere, and the reaction is carried out by raising the temperature to a predetermined temperature. let

Here, if the amount of water contained in the alkali metal sulfide is less than the predetermined amount, the necessary amount is added and replenished.

If the amount is too high, use a method known to those skilled in the art, that is, heat the solvent (and alkali metal sulfide) from 730°C to about 210°C under normal pressure before adding the dihaloaromatic compound. Remove unnecessary amounts of water from the system. At this time, if too much water is removed, the missing amount can be replenished. The amount of coexisting water in the polymerization system is 0.00% per mole of charged alkali metal sulfide. ! The range is from mol to ko, and from mol to mol. In particular, it is easy to obtain a high molecular weight PAS in the range of /, 0 mol to λ, O mol. If it is less than 0.1 mole, undesirable reactions such as decomposition of the produced PAS will occur, while if it exceeds 0.1 mole, the polymerization rate may be significantly reduced or the system may be decomposed. Neither is preferable.

The first stage polymerization is carried out at a temperature of 1 to 235°C.

If the temperature is too low, the speed is too slow, and if it exceeds 234r''C, the generated PAS (and solvent) tends to decompose, making it impossible to obtain PASL with extremely low melt viscosity.

The amount of the dihaloaromatic compound to be used is desirably in the range of 2 to 1 mole per mol of the alkali metal sulfide, and in particular, the range of 0 to 1 mole is particularly suitable for high molecular weight PAS.
preferred for obtaining. If the amount is less than 0.0 mol or/more than 1 mol, it is not preferable because it is difficult to obtain a PAS with a high viscosity suitable for processing.

At the end point of the first-stage polymerization, that is, at the time of switching from the first-stage polymerization to the second-stage polymerization, the conversion rate of the dihaloaromatic compound in the system is 3.
This is the point when it reaches 98 molti. Conversion rate is S
If the amount is less than 0 molar, undesirable reactions such as decomposition occur during the subsequent polymerization. On the other hand, if the conversion rate exceeds the
Even if stage polymerization is performed, it is difficult to obtain PAS with a high degree of polymerization. Conversion rate n morchiri! PAS with a high degree of polymerization has a molar coefficient in the chamber hole.
This is preferable because it provides the following.

Here, the conversion rate of the dihaloaromatic compound is calculated using the following formula.

C) When a dihaloaromatic compound (abbreviated as DMA) is added in excess at a smol ratio relative to the alkali metal sulfide (b) In cases other than (b), the melt viscosity of PAS changes at the time of switching from the first stage polymerization to the second stage polymerization. teeth! It should be more than poise and less than JOO boise. If it is more than lO bois and less than 200 bois,
It is suitable for obtaining PAS with a high degree of polymerization and a melt viscosity of 1000 voids or more. If it is less than j voids, it is necessary to increase the amount of coexisting water or lower the polymerization temperature during the subsequent polymerization, which tends to cause decomposition of the polymerization system and a decrease in the reaction rate. JOO Bo 4
If the amount exceeds the above, it is necessary to reduce the amount of coexisting water or raise the polymerization temperature, which is not preferable because the polymer yield decreases and the polymerization system decomposes, respectively.

(3) Post-stage polymerization In the second polymerization in the present invention, in other words, in the post-stage polymerization,
Water is added to the first stage polymerization slurry to give a total amount of water in the polymerization system of 2.5 to 7.0 moles per mole of alkali metal sulfide charged.
Make it a mole, Ko≠! The temperature is raised to 0°C to 0°C to continue polymerization. PAS having a melt viscosity of 1000 poise or more can be obtained by the post-polymerization.

When the total amount of water in the system is less than 2.3 moles or more than 7.0 moles, the melt viscosity of the produced PAR decreases.

In particular, 3. jmol~! It is preferable to carry out the post-stage polymerization in the range of 0 mol, since it is easy to obtain PAS with a high melt viscosity.

Furthermore, when the polymerization temperature is lower than 211j'C, PA81. or not obtained. On the other hand, if the temperature exceeds o''c, there is a risk that the produced PAB and the polymerization solvent will decompose.In particular, a temperature range of 210°C to 270°C is preferable because PAS with a high melt viscosity can be easily obtained.

The latter polymerization step in the present invention is not simply a step of fractionating and granulating the PAS produced in the earlier stage, but is a step for causing the former PAS to significantly increase in melt viscosity. Therefore, the polymerization time of the latter stage polymerization is determined from this point, and specifically, it is about 0.2 hours. If the polymerization time is too short, PASL with a low melt viscosity cannot be obtained, and if the reverse pressure is too long, the system will decompose. The preferred polymerization time is /-/,
1 hour, particularly preferred polymerization time is 3 to io hours.

Switching from the first stage polymerization to the second stage polymerization may be carried out by transferring the slurry obtained in the first stage polymerization to another reaction vessel and subjecting it to the second stage polymerization conditions, or the first stage polymerization and the second stage polymerization may be performed in the same reaction vessel. This may also be carried out by changing the polymerization conditions within the process.

The timing for adding water is preferably after the first stage polymerization and before the start of raising the temperature to the second stage polymerization temperature, during the temperature rise, or immediately after the temperature rise to the second stage polymerization temperature. If water is added after keeping the post-polymerization temperature for a long time with little coexisting water, P with a high melt viscosity will result.
This is not preferred because AS cannot be obtained.

(4) Post-treatment Post-treatment in the polymerization method of the present invention can be carried out by conventional methods. That is, after the completion of the second-stage polymerization reaction, jD and PAS can be obtained by separating the cooled product slurry as it is or diluting it with water or the like, washing with water, filtering, and drying repeatedly.

Produced PAS The PAs obtained by the method of the present invention have a high melt viscosity of 1000 voids or more and are substantially linear, so they can be extremely easily molded into tough heat-resistant films, sheets, fibers, etc. can. Furthermore, this PAS can be processed into various molded products by injection molding, extrusion molding, rotary molding, etc., but even if it is thick, it is difficult to crack.

Furthermore, the polymer of the present invention may be filled with powder fillers such as carbon black, calcium carbonate powder, silica powder, titanium oxide powder, or fibrous fillers such as carbon fiber, glass fiber, asbestos, and polyaramid fiber. can do.

The present invention can also use a mixture of one or more synthetic resins such as polycarbonate, polyphenylene oxide, polysulfone, polyarylene, polyacetal, polyimide, polyamide, polyester, polystyrene, and ABS.

Experimental Examples/ (1) N-methyl-pyrrolidone (hereinafter abbreviated as NMP) //, OKf, at, O2 in the first stage polymerization tank
47,232 Kp (Na, 2+8 as coj, 0 mol) of Na28j hydrate crystals (Nagaya Sota Co., Ltd. f11) containing % Na2S by weight were charged and gradually heated to 203°C with stirring for about 2 hours under a nitrogen atmosphere. Water/, 1
1! ~, N M P /, 24 m9 and 0. It mole 0H28 was distilled off.

In this case, the amount of water in the system is about 281 moles of Na/4
It has become a mole.

/JO”C, and then paradichlorobenzene (hereinafter abbreviated as p-DCB) J,jri~(λφ,4I
-λ mol) and NMPj, /7Kp were added and polymerized at 10°C for io hours to complete the first stage polymerization. j-(8-/)
I got it.

The amount of p-D'CB remaining in the slurry was determined by gas chromatography, and the conversion rate of p-DCB was determined according to the formula (b) for calculating the conversion rate. The conversion rate is between 2 and 10%.

Slurry 1001 was filtered and filtered under suction to remove liquid components. The solids were then dispersed in approximately 1K9 of deionized water and filtered again with suction to wash away the PPS produced. After repeating this operation three times, it was heated to 100℃ for two
After drying for hours (under air atmosphere), polyphenylene sulfide (pps) powder was obtained. The pressed sheet obtained by melt pressing this at 3λO℃ for 30 seconds without preheating was heated to 310℃ using a Koka type flow tester (manufactured by Takasu Seisakusho).
(preheated for 5 minutes) to measure the melt viscosity. Shear rate-ZOO
It was IOj boys in terms of 5ac-1.

(2) Post-polymerization slurry (19-/) 7j'4C11 (prepared Na2S
(equivalent to 1 mole) was placed in a 1 liter autoclave, water (total amount of water equals 281 moles of Ni) was added, and the temperature was raised to 210°C under a nitrogen atmosphere to give 1 mol of Ni.
Polymerization was carried out for 0 hours. The conversion rate of p-DCB was 60 cm. After cooling, the pore-like pps was sieved from NMP, PP8 oligomer, etc. using a sieve having a hole size of about 0.1 m.

Next, after rinsing with deionized water, heat at 100°C.
After drying for 3 hours, PPS with the following particle size distribution (based on the water sieve method) was obtained.

The yield was approx. The yield mentioned here refers to the amount (
This is the ratio of recovered pearl-like PAS to the theoretical amount).

Particle size 0.31 m or less 0 wt% po,
3t~0. G2 0. Ko 〃I Q,≠Ko〜o
,'yi i3. zpl 0.7/~/
, 00 jJ, Ko 〃I 1+00~1. ≠
13≠, 1 11 1, Hiro/m or more O〃 The apparent specific gravity of the obtained pearl-like PPS was Hiro 3117 di. Moreover, the melt viscosity was zqoo voids.

Example Co~j Using the slurry of 8-/, the polymerization time was changed to /-/! in the same manner as in Example 1. Post-polymerization was carried out by changing the time within the range of i (Examples λ to 1).Also, using a slurry of S-/,
H20/N Todoroki 2S as coexisting water amount by changing the amount of added water
Post-stage polymerization was carried out at a molar ratio in the range of 3.0-3.0 (Examples 6 to t). In either case, pearl-like PPS with high melt viscosity was obtained. The results are summarized in Table C.

Example 19 The molar ratio (
p-DCB/Na28 molar ratio), amount of coexisting water (120/N
(S mole ratio), charging concentration (number of moles of Na2S in NMP/Kp), polymerization temperature, and polymerization time.

Various pre-stage slurries (S-λ~7.5-10~/4A) were obtained. The conversion rate and melt viscosity of the produced PPS were determined for each. The polymerization conditions and results are as shown in Table 1.

Next, using these slurries, the post-polymerization conditions are shown in Table 2.
The second stage polymerization was carried out with the following changes. The results were as shown in Table-2. In all cases, it was possible to obtain particles of high melt viscosity and in most cases a round shape.

Comparative Example 1 First-stage polymerization slurry (B −/ ) 71≠ttt! Ti
Place in a little autoclave and place under nitrogen atmosphere without adding water! Post-polymerization was carried out at 0° C. for 10 hours.

After cooling, the pps was separated from the NMP by suction filtration.

Next, this PPS was washed repeatedly with deionized water, and then heated at 100℃! After drying for a few hours, a fine powder polymer was obtained with a yield of t, a melt viscosity of 10 voids, and an apparent specific gravity of l-
M/di (the results are summarized in Table 1).

Comparative example first stage polymerization slurry (S-i)yz4! Put i into a 7 liter autoclave and add water//! 0.2 JiF (total amount of water r, o mol) added, under nitrogen atmosphere, 2jj'
Post-polymerization was carried out at C for 10 hours.

After cooling, pps was collected in the same manner as in Comparative Example 1. A fine sandy polymer was obtained. The yield was 7 cm, and the melt viscosity was ≠10 voids, indicating that the melt viscosity did not increase if too much water was added in the post-polymerization (the results are shown in Table 2).

Comparative example 3 The amount of coexisting water was defined as j moles per mole of Na2S.

Except for this, the procedure was almost the same as in Example 1, and the temperature was 10°C at -io°C.
Polymerization was carried out for a period of time to obtain a pre-polymerized slurry (V-<5-t). The conversion rate ry, rts, and melt viscosity of the first-stage PPS were below jboise (the results are summarized in Table 1).

Pour 770 g of this slurry into a 1 liter auto pump, add 3611 g of water, and heat it under nitrogen atmosphere for 220 g.
Post-polymerization was carried out at °C for 10 hours to obtain granular Pps. The yield was 7♂H, and the melt viscosity of pps was IIJO poise. If the amount of water in the first stage polymerization was too small, the melt viscosity could not be increased, and the slurry after the second stage polymerization had a bad odor and was on the verge of decomposition (the results are summarized in Table λ).

Comparative example ≠ NMP/SioKP, pt, in side liter autoclave
Na28 J water salt crystal 4A containing o% by weight of Na28
, 07 Q (as Na28, 2 tons 0 hairs), p-D
CB! , 701-(21.20 mol) were charged and reacted at 210° C. for a period of time in a nitrogen atmosphere without draining water to obtain a pre-polymerization slurry 9-(S-ta). The conversion rate is rj, O
H. The melt viscosity of the pps obtained in the first stage was less than j poise (the results are summarized in Table 7).

When this slurry (S-ta) ffJll was charged into a 1 liter autoclave and post-polymerization was carried out at 2!0° C. for 10 hours in a nitrogen atmosphere, decomposition occurred and the polymerization did not proceed. The melt viscosity of the granular PPS obtained in a small amount was below J-Boise (the results are summarized in Table 1).

Comparative example! First-stage polymerization slurry obtained in Comparative Example≠! J-(8-5')rsa
. When polymerization was carried out at 210° C. for a total of 3 hours, the reaction solution gave off a bad odor and was decomposed. The melt viscosity of the small amount of PPS recovered was 9 voids or less.

Comparative Example 6 First-stage polymerization slurry (,5-t) r Riza 11 (Na2S
Charged amount (equivalent to 12λ moles) was charged into a 1 liter autoclave and placed in a nitrogen atmosphere for 2 hours. Raise the temperature to tO℃! Polymerization was carried out for a period of time to complete the reaction. After cooling, 00.9 was sampled, and the conversion rate and the melt viscosity of the pps produced were determined according to the formula (a) for calculating the conversion rate.

Conversion rate tata, melt viscosity r of 2 mol pps, 2 voids, then water j7. tli (total amount of J mol) was heated again to 2.70°C under a nitrogen atmosphere, and reacted for io hours to form sandy or granular pp.
I got s. The yield was 65 cm, the apparent specific gravity was 3/I/dl, and the melt viscosity was 00 voids. The particle size distribution was as shown below.

Particle size 0. IOr tx or less O weight value y o,
ioz~Q, 3! Ko≠, 3 11 0.3! r
~O0≠ko 12.7 1#0. g+2-0.7
1 ≠ 3. ! 〃Particle size 0.71~/,00
10J weight%1 1. DO~1. ≠／
j, 0 /'1 /, l11w5 or more
3#7 If the conversion rate becomes too high in the first stage polymerization, the melt viscosity will not increase even if the second stage polymerization is performed under condition 4 of the present invention.

Example m In a 10 liter autoclave, add NMP Hiro hoop and l
/-bu, N Todoroki 2S containing 0% by weight of Na2S! Water salt crystals were charged with J,9 (io mol as Na2S), and while gradually heating up to 202°C in a nitrogen atmosphere, water was added with 6
11311, NMPII/71 and 0. J/ Mokf
) H2O was distilled off. In this case, the amount of water in the system is N
It is about 1.33 mol per 281 mol of a. After cooling to iso℃, p-DCB/≠321 (p-DCB/N breath 2
S molar ratio 1,0///, OO) and NMP76 were added, and polymerization was carried out at 210° C. for 10 hours to obtain a pre-polymerization slurry. When a small amount of this was sampled and investigated, the conversion rate was 3%, and the melt viscosity of the PPS produced was approximately 10.
There was 0 voice.

Next, this first-stage polymerization slurry was heated with K and water ψAn without being cooled.
is injected with nitrogen and the total amount of water is 6 per mole of Na28.
0 mol), the temperature was raised to 80° C., and post-polymerization was carried out for 10 hours. The conversion rate of p-DCB was Z≠.

Thereafter, a pellet-shaped PPS was collected in the same manner as in Example 1. The polymer yield was IRt1, and the melt viscosity was 74!00 voids.

Comparative Example 7 First-stage polymerization slurry (S-/) yz4Li was charged into a 1 liter autoclave, and 2jO'' was added in a nitrogen atmosphere without adding water (total water amount was 1.6 mol per 1 mol of Na2B). C., and polymerization was continued for 1 hour to complete the reaction.Next, without cooling, water !2.211 was pressurized with nitrogen gas.The temperature was once lowered to about 220°C, but After further heating and the temperature recovered to 80°C, the heating was immediately stopped. Recovery was carried out in the same manner as in Example 1 to obtain granular (non-spherical) pps.p-DCB
The conversion rate was P, J%, the yield was 70'%, and the melt viscosity of PP8 was 240 boids. The particle size distribution of the obtained pps was similar to that of Comparative Example B.

Comparative Example t Slurry obtained by polymerization at 210°C/10 hours under conditions containing 1)/1 mole of Na2B/1 mole of H2O (
S-/) 7!4!11 was placed in a liter autoclave, 142 g of water (total amount of water equal to 281 mol of Na, ! mol) was added, and the mixture was heated from room temperature under a nitrogen atmosphere.
The temperature was raised to 210°C over about 1 hour. After reaching -210'C, it was immediately cooled. The conversion rate of p-DCB is y
It was yr4. Thereafter, post-treatment was performed in the same manner as in Example 1. Granular (non-spherical) pps were obtained. Polymer yield is approximately A#i. Melt viscosity is go.

It was Boyz.

Example 2 The first stage polymerization was carried out under exactly the same conditions as in Example 1, and -2jO
Post-polymerization was carried out at °C for 10 hours. Next, the mixture was kept at 2JO<0>C for 30 minutes while stirring was stopped, and then cooled to room temperature over about 2 hours while stirring was stopped.

Thereafter, the same post-treatment as in Example 1 was carried out to obtain pearl-like PPS. Yield r3chi, melting degree 000
It was Boyz.

The particle size distribution of the obtained PP80 was almost the same as in Example 1, and the individual particles were not flattened or fused together. Therefore, it is considered that the pearl-like particles are not formed during the cooling process after the post-polymerization, but are formed during the post-polymerization and gradually harden to the extent that they do not fuse.

procedural amendment side July 23, 1980

Claims (1)

[Claims] A method for obtaining polyarylene sulfide by reacting an alkali metal sulfide and a dihaloaromatic compound in an organic amide solvent, characterized in that the reaction is carried out in at least the following two steps: A method for producing polyarylene sulfide having a viscosity of 1000 voids or more (however, in the present invention, the melt viscosity is 310°C and the shear rate is 200 (seconds)^
-1). (1) In the presence of 0.5 to 2.4 moles of water per mole of alkali metal sulfide, a reaction is carried out at a temperature of 180 to 235°C to convert polyarylene sulfide with a melt viscosity of 5 to 300 voids into dihalogen. Conversion rate of aromatic compounds 50-9
(2) adding water so that 2.5 to 7.0 mol of water exists per 1 mol of alkali metal sulfide and raising the temperature to 245 to 290°C; and continuing the above reaction.