JPH04255721A - Production of polyarylene sulfide - Google Patents

Abstract

PURPOSE:To produce a polyarylene sulfide having high molecular weight in a short time in high yield. CONSTITUTION:A polyarylene sulfide is produced by reacting (A) a sulfur source selected from an alkali metal sulfide, alkali metal hydrosulfide and hydrogen sulfide with (B) an alkali metal hydroxide and a polyhalogenated aromatic compound (in the case of using the above sulfur source other than the alkali metal sulfide) or a polyhalogenated aromatic compound (in the case of using the alkali metal sulfide as the above sulfur source) in an organic polar solvent. In the above process, the reaction solution is heated from <=220 deg.C to >=260 deg.C at a heating rate of <=0.5 deg.C/min on an average in the presence of <0.3mol of water and an alkali metal carboxylate based on 1mol of S in the sulfur source.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is for producing high-molecular weight polyarylene sulfide, which is suitable as a material for various molded products, films, sheets, fibers, mechanical parts, electrical and electronic parts, etc., in a short time and economically. It is about the method.

0002

[Prior Art] Polyarylene sulfide has excellent heat resistance and chemical resistance, and also has good mechanical properties, flame retardance, dimensional stability, and processability, so it is used as engineering plastics for automobile parts, electrical and electrical equipment, etc. It is widely used in many fields such as electronic parts, precision mechanical parts, and OA equipment parts.

As a method for producing polyarylene sulfide, a method is known in which a dihalogenated aromatic compound and sodium sulfide are reacted in an organic amide solvent such as N-methylpyrrolidone. (Tokuko Sho 45-3368
Publication No.)

However, with this method, the molecular weight of the polyarylene sulfide obtained does not become sufficiently large. For example, the weight average molecular weight is 20,000 or less (the weight average molecular weight can be measured by GPC method, light scattering method, etc. in a solution of the polymer in α-chlornaphthalene at a high temperature of 200° C. or higher). Therefore, due to the low melt viscosity, there was a problem in that it was difficult to mold them into films, sheets, fibers, etc.

Various methods have been proposed to improve this point and obtain polyarylene sulfide with a high degree of polymerization. Typical examples include a method in which the reaction is carried out in two stages in the presence of water (Japanese Patent Publication No. 7332/1983) and a method using an alkali metal carboxylate as a polymerization aid (Japanese Patent Publication No. 12240/1982). ) has been proposed.

Although the polyarylene sulfide obtained by these methods has a high degree of polymerization, for example, the weight average molecular weight is about 40,000 to 50,000, and the degree of polymerization is about 400 to 50,000.
500, which is still not sufficient.In order to obtain a polyarylene sulfide with a higher molecular weight of 60,000 or more and a polymerization degree of 600 or more, the polymerization time may be increased to 12 hours or more, or a polymerization aid may be added. It is necessary to use a large amount of 0.5 mole or more per mole of the sulfur source used, which results in an economical problem such as an increase in the production cost of polyarylene sulfide.

Alternatively, if one simply wants to increase the melt viscosity or molecular weight, there is a method of introducing a crosslinked structure using a compound having three or more halogen atoms (Japanese Patent Publication No. 54-8
(No. 719) The high molecular weight polyarylene sulfide obtained by this method has problems such as poor spinnability and film forming properties due to loss of linearity when introduced in a large amount.

[0008]

[Problems to be Solved by the Invention] The present invention overcomes the drawbacks of the conventional method for producing high molecular weight polyarylene sulfide, and produces high molecular weight polyarylene sulfide in a short time and with high yield. The present invention provides a method. Here, high molecular weight refers to a molecular weight of about 60,000 or more, and short time refers to a polymerization time of less than 12 hours. Moreover, high yield means at least 80% or more.

[0009]

[Means for solving the problem] The above purpose is to perform polymerization in the presence of a regulated amount of water and an alkali metal carboxylate while controlling the heating rate of the reaction system in the production of polyarylene sulfide. achieved by.

That is, the present invention provides a sulfur source selected from alkali sulfide, alkali hydrosulfide, and hydrogen sulfide in an organic polar solvent, and when a sulfur source other than alkali sulfide is used, an alkali metal In the method for obtaining polyarylene sulfide by reacting a hydroxide and a polyhalogenated aromatic compound, and when using an alkali sulfide as the sulfur source, the reaction solution is From temperature below ℃ to 260℃
When the temperature is raised to above, the reaction is carried out at an average heating rate of 0.5°C/min or less in the presence of less than 0.3 mol of water and alkali metal carboxylate per 1 mol of S in the sulfur source. The present invention provides a method for producing polyarylene sulfide characterized by the following.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The polyarylene sulfide produced in the present invention has the formula

It is a homopolymer or copolymer whose main constituent unit is the repeating unit of [Chemical 1]. As long as this repeating unit is the main constituent unit,

It may contain a small amount of branched bond or crosslinked bond represented by the formula 2 and the like.

[0012] As Ar

[Chemical formula 3]

embedded image (R1 and R2 are hydrogen, alkyl group, alkoxy group,
(selected from halogen groups). Particularly preferred polyarylene sulfides include p-phenylene units as the main structural unit of the polymer.

Polyphenylene sulfide containing 90 mol% or more of
(hereinafter also referred to as PPS), polyphenylene sulfide sulfone, and polyphenylene sulfide ketone.

The sulfur source of the present invention includes alkali sulfide,
At least one selected from alkali hydrosulfide and hydrogen sulfide can be used as the sulfur source. Examples of the alkali sulfide include sodium sulfide, potassium sulfide, lithium sulfide, rubidium sulfide, and cesium sulfide, among which sodium sulfide is preferably used. Alkali hydrosulfides include sodium hydrosulfide, potassium hydrosulfide,
Lithium bisulfide, rubidium bisulfide, cesium bisulfide, etc. can be mentioned, and among these, sodium bisulfide is preferably used.

The alkali metal hydroxide of the present invention includes:
Sodium hydroxide, potassium hydroxide, lithium hydroxide,
Examples include rubidium hydroxide and cesium hydroxide, and among them, sodium hydroxide is preferably used.

[0015] When alkali sulfide is used as a sulfur source, there is no difference in the case where an alkali metal hydroxide is used in combination with the case where an alkali metal hydroxide is not used. However, alkali hydrosulfide (NaSH)
) and hydrogen sulfide (H2S), the degree of polymerization will not increase unless they are used together. In other words, it is necessary to exist as an alkali sulfide as a sulfur source during PPS polymerization. The reason for this is thought to be as follows. For example, when the alkali metal is Na: Sodium sulfide (Na2S) --- Sufficient degree of polymerization Sodium hydrosulfide (NaSH) + Sodium hydroxide (NaOH) → Na2S

────Polymerization degree is sufficient Hydrogen sulfide (H2S) + Sodium hydroxide (2Na
OH)→Na2S

────Polymerization degree is sufficient

00
16] The polyhalogenated aromatic compound of the present invention refers to a compound having two or more halogen atoms and a molecular weight of less than 1,000. Specific examples include p-dichlorobenzene, m-dichlorobenzene, o-dichlorobenzene, 1,3,5-
Trichlorobenzene, 1,2,4-trichlorobenzene, 1,2,4,5-tetrachlorobenzene, hexachlorobenzene, 2,5-dichlorotoluene, 2,5-dichloro-p-xylene, 1,4- Dibromobenzene, 1,
4-dichloronaphthalene, 1,5-dichloronaphthalene, 1-methoxy-2,5-dichlorobenzene, 4,4'
-dichlorobiphenyl, 3,5-dichlorobenzoic acid, 4
, 4'-dichlorodiphenyl ether, 4,4'-dichlorodiphenyl sulfone, and 4,4'-dichlorodiphenyl ketone. 4'-dichlorodiphenyl sulfone and 4,4'-dichlordiphenyl ketone are preferably used.

Examples of the organic polar solvent of the present invention include N-methylpyrrolidone, N-methylcaprolactam, N,N-dimethylacetamide, N,N-dimethylformamide, hexamethylphosphoric triamide, dimethylsulfone, and tetramethylene sulfoxide. Among them, N-methylpyrrolidone is preferably used.

The alkali metal carboxylates of the present invention include lithium acetate, sodium acetate, potassium acetate, lithium propionate, sodium propionate, lithium 2-methylpropionate, rubidium butyrate, lithium valerate, sodium valerate, and hexane. Cesium acid, lithium heptanoate, lithium 2-methyloctoate, potassium dodecanoate, rubidium 4-ethyltetradecanoate, sodium octadecanoate, sodium heneicosanoate, lithium cyclohexanecarboxylate, cesium cyclododecanecarboxylate, 3-methylcyclopentanecarboxylate sodium acid, potassium cyclohexyl acetate, potassium benzoate, lithium benzoate, sodium benzoate, potassium m-toluate, lithium phenylacetate,
Sodium 4-phenylcyclohexanecarboxylate, p
- Potassium tolyl acetate, lithium 4-ethylcyclohexyl acetate, other salts of the same type, and mixtures thereof, among which lithium acetate, sodium acetate, sodium benzoate, and lithium benzoate are preferably used.

In the reaction of the present invention, the polymerization reaction temperature is not preferably 220° C. or lower because the polymerization reaction is difficult to occur, and a temperature of 260° C. or higher is preferable in order to sufficiently advance the polymerization reaction. Also, the rate of temperature increase when increasing the temperature from below 220°C to above 260°C is 0.
．． The temperature is preferably 5° C./min or less, and increasing the temperature at a rate higher than this rate is not preferable because side reactions tend to occur and the degree of polymerization of the obtained polyarylene sulfide does not increase.

In the reaction of the present invention, the amount of water present in the system at the initial stage of the reaction is preferably less than 0.3 mol per 1 mol of S in the sulfur source. This is not preferred because the degree of polymerization of sulfide does not become large and the reaction vessel becomes severely corroded.

In the reaction of the present invention, a crosslinked structure can be introduced using a compound having three or more halogen atoms, but the amount added is 0.5 mol of the total amount of the polyhalogenated aromatic compound. % or less is preferable. It is not preferable to add a compound having three or more halogen atoms in an amount of 0.5 mol % or more because the spinnability and film-forming properties of the resulting polyarylene sulfide deteriorate.

In addition, in the reaction of the present invention, auxiliary agents such as organic sulfonates, alkaline earth metal oxides, alkali metal phosphates, alkaline earth metal phosphates, etc. can be added. , an inorganic acid, a terminal capping agent, etc. can be added. Moreover, water can also be added in the late stage of polymerization.

The amount of the polyhalogenated aromatic compound remaining in the reaction solution after the reaction in the present invention is 2.
It is preferably 5 mol% or less, particularly 0.5 to 2.
0 mol% is preferred. If it exceeds 2.5 mol%, the resulting polyarylene sulfide will have a small molecular weight, which is not preferable.

The polyarylene sulfide reacted in the present invention is obtained by washing with a polar organic solvent or water and drying. The obtained polyarylene sulfide has a high molecular weight, and when used in fibers, films, molding resin compositions, etc., molded articles with excellent mechanical properties can be obtained.

[0025] Furthermore, inorganic fillers such as glass fiber, carbon fiber, titanium oxide, and calcium carbonate, antioxidants, heat stabilizers, ultraviolet absorbers, colorants, and the like may be added.

In addition, polyamide, polysulfone, polyphenylene oxide, polycarbonate, polyether sulfone, polyethylene terephthalate, polybutylene terephthalate, polyethylene, polypropylene, polytetrafluoroethylene, polyether ester elastomer, polyether amide elastomer, polyamideimide, polyacetal, polyimide It is also possible to blend resins such as.

[0027]

EXAMPLES The present invention will be explained in more detail below using examples. The melt flow rate in the present invention is A
Temperature 315.according to STM D-12380-70.
It was measured at 6°C and a load of 5 kg. The unit is g/
It's 10 minutes.

Example 1 In a 1-liter autoclave equipped with a stirrer, 245.0 g (1.02 mol) of sodium sulfide nonahydrate and 24 g of sodium acetate were added.
．． 6 g (0.3 mol), about 48% aqueous sodium hydroxide solution 2.5 g (0.03 mol) and 198 g (2.0 mol) of N-methyl-2-pyrrolidone, and heated to 205°C while passing nitrogen through the mixture for about 3 mols. The mixture was heated gradually over a period of time, and 164 g of a distillate containing water as a main component was distilled out. The amount of water remaining in the system was 0.14 mol.

The reaction vessel was cooled to 180°C, and 147 g (1.0 mol) of p-dichlorobenzene and N-methyl-
149 g (1.5 mol) of 2-pyrrolidone was added, the mixture was sealed under nitrogen gas pressure, and the temperature was raised to 210°C.

[0030] The reaction vessel was heated from 210°C to 225°C.
Raise the temperature at a heating rate of 5°C/min, then increase the temperature by 0.3°C to 270°C.
The temperature was raised at a rate of .degree. C./min, and the reaction was carried out at 270.degree. C. for 110 minutes. The time from the internal temperature of 210°C to the end of the polymerization reaction was 280 minutes.

After cooling the reaction vessel slowly at a rate of 1° C./min, the contents were taken out and the amount of remaining p-dichlorobenzene was analyzed by gas chromatography and found to be 1.2 mol %. . The contents were washed with 500 g of N-methyl-2-pyrrolidone at 70°C, washed six times with 700 g of water at 70°C, and dried under reduced pressure at 120°C.

The yield of the polyphenylene sulfide obtained was 89%, and the melt flow rate was 64 g/10 minutes. During the dehydration process in this operation, the amount of hydrogen sulfide scattered is 2
．． It was 0 mol%.

Example 2 After sealing the reaction vessel, the temperature was increased from 210°C to 270°C by 0.3°C/
The same operation as in Example 1 was carried out, except that the temperature was raised at a rate of 1 minute and the reaction was carried out at 270° C. for 70 minutes. The time from the internal temperature of 210°C to the end of the polymerization reaction was 280 minutes. Yield 84%
The melt flow rate of the polyphenylene sulfide obtained was 76 g/10 minutes, and the remaining p-dichlorobenzene was 1.4 mol%.

Example 3 In a 1 liter autoclave similar to Example 1, 45%
Sodium hydrosulfide 127.1 g (1.02 mol), sodium hydroxide 40.0 g (1.0 mol), sodium acetate 24.6 g (0.30 mol) and N-methyl-2-
Example 1: Pyrrolidone 198g (2.0mol) was charged.
The mixture was heated in the same manner as above, and 66 g of a distillate containing water as a main component was distilled out. The amount of water remaining in the system was 0.22 mol.

The reaction vessel was cooled to 180°C, and 147 g (1.0 mol) of p-dichlorobenzene and N-methyl-
149 g (1.5 mol) of 2-pyrrolidone was added, the mixture was sealed under nitrogen gas pressure, and the temperature was raised to 210°C.

Next, from 210°C to 225°C, increase the temperature by 0.5°C/
The temperature was raised at a rate of 1 minute, and after reacting at 225℃ for 30 minutes,
．． The temperature was raised to 270°C at a rate of 3°C/min.
The reaction was carried out at ℃ for 70 minutes.

After the reaction was completed, 18 g of water was added at a rate of 1 ml/min while cooling the reaction vessel at a rate of 1° C./min. Thereafter, the mixture was cooled, washed, and dried in the same manner as in Example 1 to obtain polyphenylene sulfide in a yield of 87%. The remaining p-dichlorobenzene is 1.6 mol%, and the melt flow rate is 5.
It was 2g/10 minutes. Further, the time from the internal temperature of 210°C to the end of the polymerization reaction was 280 minutes.

Example 4 The same procedure as in Example 3 was carried out, except that after sealing the reaction vessel, the reaction was carried out at 225°C for 106 minutes, and then the temperature was increased at a rate of 0.5°C/min and the reaction was carried out at 270°C for 55 minutes. I did it. Internal temperature 210℃
The time from the start to the end of the polymerization reaction was 280 minutes. The melt flow rate of polyphenylene sulfide obtained with a yield of 87% was 85 g/10 minutes, and the remaining p-dichlorobenzene was 1.9 mol %.

Example 5 Polymerization was carried out using the same recipe as in Example 3, except that 155.9 g (1.0 mol) of p-dibromobenzene was used instead of p-dichlorobenzene. The remaining p-dibromobenzene was 0.7 mol%, and the melt flow rate was 8.
3g/10min of polymer was obtained. Here, 0 to 270℃
．． The temperature was increased at a rate of 5°C/min, and when the temperature reached 270°C, the reaction vessel began to cool down at a rate of 1°C/min. The time from the internal temperature of 210°C to the end of the polymerization reaction was 210 minutes.

Example 6 In Example 1, 45% sodium hydroxide was added instead of sodium hydroxide.
The same polymerization procedure was carried out except that 2.0 g (0.016 mol) of sodium hydrosulfide was used. Particulate polymer is 9
Obtained with a yield of 2% and a melt flow rate of 48g/1
It was 0 minutes. During the dehydration step of this operation, the amount of hydrogen sulfide scattered was 2.8 mol % based on sodium bisulfide.

Comparative Example 1 In Example 1, from 210°C to 270°C, 0.6°C/
All operations were carried out in the same manner as in Example 1, except that the temperature was raised at a rate of 270° C. and the reaction was carried out at 270° C. for 170 minutes. The melt flow rate of the obtained polyphenylene sulfide was 624 g/10 minutes, and the remaining p-dichlorobenzene was 1.0 mol %. Also, the yield of polymer was 79%
Met.

Comparative Example 2 When adding p-dichlorobenzene, 18 g (18 g) of water was added at the same time.
The same operations as in Example 1 were performed except that mol) was added. The melt flow rate of the obtained polyphenylene sulfide was 1100 g/10 minutes, and the remaining p-dichlorobenzene was 0.4 mol %. Moreover, the yield of the polymer was 63%.

Comparative Example 3 The same operations as in Example 1 were carried out except that sodium acetate was not added. The melt flow rate of the obtained polyphenylene sulfide was 1400 g/10 minutes, and the remaining p-dichlorobenzene was 1.5 mol %. Moreover, the yield of the polymer was 80%.

Comparative Example 4 The same procedure as in Example 1 was carried out except that 150 g (1.02 mol) of p-dichlorobenzene was added. The melt flow rate of the obtained polyphenylene sulfide was 7
The p-dichlorobenzene remaining at 30 g/10 minutes was 2.9 mol%. In addition, the yield of polymer was 82%
Met.

Comparative Example 5 The same procedure as in Example 1 was carried out except that 145.5 g (0.99 mol) of p-dichlorobenzene and 1.8 g (0.01 mol) of 1,2,4-trichlorobenzene were added. The melt flow rate of the polyphenylene sulfide obtained after the operation was 45 g/10 minutes, and the remaining p-dichlorobenzene was 1.2 mol %. Moreover, the yield of the polymer was 81%. However, with this polymer, thread breakage occurred during spinning.

Comparative Example 6 Using a 1 liter container with an extraction cock at the bottom,
Dehydration was performed using the same recipe as in Example 1. After cooling this system to 180°C, 147 g of p-dichlorobenzene (
1.0 mol) and 149 g of N-methylpyrrolidone were added, the mixture was sealed in a nitrogen atmosphere, and the mixture was heated to 210°C and kept constant. Remove the contents and use a cooker to add approximately 50g each.
After 0 and 20 hours, the powdered polymer was taken out, washed with water, and dried, and the melt flow rate was measured, and the results were as follows.

[Table 1] ────────────────────
────────────
melt flow rate
Molecular weight ──────────────
────────────────────
5 hours later 5000 or more
15,000 or less 10
5000 or more
〃 20
3800
17500 ────────
────────────────────────

0
Comparative Example 7 The same polymerization procedure as in Example 3 was carried out except that sodium hydroxide was used. 7 in the dehydration process
At the same time as 0 g of distillate was obtained, 3.5 mol% of hydrogen sulfide was scattered based on the sodium hydrogen sulfide used. The polymer after washing is in powder form, and the melt flow rate is 3200g/
It was 10 minutes. On the other hand, in this system, 210℃ to 270℃
The melt flow rate of a finely powdered polymer obtained by the same operation was as high as 6,700 g/10 min.

Next, the physical properties of molded products obtained when the polymers obtained in Example 1 and Comparative Example 1 were directly molded using the injection molding machine described below will be shown. Sumitomo Nestal SG75 Injection temperature 320℃ Mold temperature 150℃ Test piece JIS-K7113

[Table 2] ──────────────────────────
──────────

Example 1 Comparative example 1──────────
──────────────────────────
─ Tensile strength (kg/cm2)
891 770
stretch (%)
12.5
3.8 Weld strength (kg/cm2)
820 750
Bending strength (kg/cm2)
1450 1412 Impact strength
without destruction 29
No notch (kg・cm/cm2)
(60 or more)──────────────
──────────────────────

004
9] The polymers in the practical (comparative) examples all have a glass transition temperature of 89 to 92°C and a melting point of 275 to 295°C,
It is presumed to have a polyphenylene sulfide structure as a repeating unit.

[0050] In the practical (comparative) examples, the value of the melt flow rate is described, and there is a certain relationship between this value and the molecular weight (or degree of polymerization). Also, molecular weight = 108×
It is the degree of polymerization. Therefore, the melt flow rate and molecular weight of the polymers obtained in each practical (comparative) example are shown in the table below.

[Table 3]

As can be seen from the above table, in Examples 1 to 6 of the present invention, the melt flow rate was low and the degree of polymerization of the obtained polymers was high. In addition, Example 1
During the dehydration step, 2.0 mol% of hydrogen sulfide was scattered, and the amount of hydrogen sulfide scattered in Example 6 was 2.8 mol%. ) suggests that it reduces the loss of sulfur sources.

Comparative Examples 1 to 7 in contrast to Examples 1 to 6 above
When the temperature increase rate is fast (Comparative Example 1), when the polymerization reaction temperature is 220°C or less (Comparative Example 6), when there is a large amount of water in the system during the polymerization reaction (Comparative Example 2) , when there is no alkali metal carboxylate (Comparative Example 3), when there is a large amount of residual polyhalogenated aromatic compound (Comparative Example 4)
), and when using something other than sodium sulfide as a sulfur source and not using an alkali metal hydroxide (Comparative Example 7), polyarylene sulfide with a high degree of polymerization cannot be obtained. In addition, when many crosslinked structures are introduced (
Comparative Example 5) Although the degree of polymerization increases, the properties of the polymer are impaired.

[0053]

[Effect of the invention] In the conventionally known method for producing polyarylene sulfide, the temperature increase rate of the reaction system was broadly set as a general description, but as in the present invention, it is controlled to specific conditions. As a result, polyarylene sulfide with a high degree of polymerization can be obtained in a short time (less than 12 hours, for example, 210 minutes to 280 minutes), and the yield of polyarylene sulfide obtained as a secondary product is also improved.

Claims (3)

[Claims] Claim 1: When using a sulfur source selected from alkali sulfide, alkali hydrosulfide, and hydrogen sulfide in an organic polar solvent, and as the sulfur source other than alkali sulfide, an alkali metal hydroxide and In the method of obtaining polyarylene sulfide by reacting a polyhalogenated aromatic compound and, when using an alkali sulfide as the sulfur source, the reaction solution is heated to a temperature of 220°C or less. 0.5°C on average in the presence of less than 0.3 mole of water and alkali metal carboxylate per mole of S in the sulfur source when increasing the temperature from
1. A method for producing polyarylene sulfide, characterized in that the reaction is carried out at a temperature increase rate of /min or less. 2. The method according to claim 1, wherein the amount of the polyhalogenated aromatic compound remaining after completion of the reaction is 2.5 mol % or less of the amount supplied. 3. The method according to claim 1, wherein the polyarylene sulfide has a melt flow rate of 500 or less.