JPH04255722A - Production of polyarylene sulfide - Google Patents

Abstract

PURPOSE:To produce a polyarylene sulfide having high molecular weight in a short time. 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, water is added to the system at >=23O deg.C in the latter stage of the polymerization reaction to adjust the molar ratio of H2O/polymer to 0.2-4.0 and reaction is proceeded for >=20min at >=240 deg.C.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a method for producing high molecular weight polyarylene sulfide in a short time, which is suitable as a material for various molded products, films, sheets, fibers, mechanical parts, and electrical/electronic parts. be.

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 parts, etc.・Electronic parts,
It is widely used in many fields such as precision machine 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, the polyarylene sulfide obtained by this method does not have a sufficiently large molecular weight. 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, there was a problem in that it was difficult to mold into films, sheets, fibers, etc. due to the low melt viscosity.

Various methods have been proposed to improve this point and obtain polyarylene sulfide with a high degree of polymerization. A typical method is a method using an alkali metal carboxylate as a polymerization aid (Japanese Patent Publication No. 52-1224
0), a method in which the polymerization reaction is carried out in the presence of water from the initial stage (JP-A-61-7332), and a method in which the polymerization reaction is carried out in the presence of water and a metal carboxylate (JP-A-61-7332). 64-9229).

However, it is not preferable to carry out the polymerization reaction in the presence of water from the initial stage because the reaction vessel becomes severely corroded. Furthermore, in order to suppress corrosion, a reaction vessel made of an expensive material such as titanium must be used, which poses an economical problem.

[0007] Polymerization using only an alkali metal carboxylate as a polymerization aid increases the molecular weight, but there are problems such as the need for a long polymerization time, usually 9 hours or more. Furthermore, although the method of adding water at the end of polymerization (Japanese Patent Publication No. 1-25493) improves the polymer yield, there is a problem that the molecular weight is difficult to increase because no polymerization aid is added during the polymerization reaction.

[0008]

[Problems to be Solved by the Invention] The present invention overcomes the drawbacks of the conventional methods for producing high molecular weight polyarylene sulfide and relates to a method for producing high molecular weight polyarylene sulfide in a short time. . Here, the term "high molecular weight" refers to a weight average molecular weight of 40,000 or more, and the term "short time" refers to a polymerization time of 9 hours or less. Moreover, high yield means at least 80% or more.

[0009]

[Means for solving the problem] The above purpose is to carry out a polymerization reaction in the presence of a regulated amount of water and an alkali metal carboxylate in the production of polyarylene sulfide, and in the late stage of the polymerization to produce a regulated amount of H2O. /polymer molar ratio, and the reaction solution is heated to a regulated temperature or higher,
This is achieved by a controlled time reaction.

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 using something other than alkali sulfide as the sulfur source, alkali metal water. In the method of obtaining polyarylene sulfide by reacting an oxide and a polyhalogenated aromatic compound, and when using an alkali sulfide as the sulfur source, 230 Production of polyarylene sulfide, characterized by adding water at a temperature of 240°C or higher, adjusting the H2O/polymer ratio to 0.2 to 4.0, and reacting at a temperature of 240°C or higher for at least 20 minutes. The present invention provides a method.

[0011] The late stage of the polymerization reaction refers to the time after the residual polyhalogenated aromatic compound becomes at least 8 mol%, preferably 5 mol% or less.

0012

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.

[0013] 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 sometimes referred to as PPS), polyphenylene sulfide sulfone, and polyphenylene sulfide ketone.

[0014] As the sulfur source of the present invention, 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.

[0016] When an 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, if the alkali metal is Na: Sodium sulfide (Na2S)...Polymerization degree is sufficient
Sodium hydrosulfide (NaSH) + sodium hydroxide (
NaOH)→Na2S
...Polymerization degree is sufficient Hydrogen sulfide (H2S) + Sodium hydroxide (2NaOH)
→Na2S
...Polymerization degree is sufficient

The polyhalogenated aromatic compound of the present invention has 2 halogen atoms.
It refers to a compound with a molecular weight of 1,000 or more 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, 4,4'-dichlorodiphenyl ketone and other polyhalogen-substituted, aromatic compounds, among which p- Dichlorobenzene, 4,4'-dichlorodiphenyl sulfone, and 4,4'-dichlorodiphenyl 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, organic sulfonates, alkaline earth metal oxides, alkali metal phosphates,
Auxiliary agents such as alkaline earth metal phosphates can be added, as well as organic acids, inorganic acids, terminal blocking agents, and the like.

[0021] In the present invention, the temperature at which water is added in the latter half of the polymerization reaction is preferably 230°C or higher; if it is lower than 230°C, the polymer in the reaction solution will not form a molten phase, making it difficult for the effect of water addition to appear, which is not preferred. .

The H2O/polymer molar ratio after water addition is 0.
．． 2 to 4.0 is preferable, and 0.5 to 3.0 is particularly preferable. If this ratio is less than 0.2, the effect of water addition cannot be obtained, which is undesirable, and if it exceeds 4.0, the pressure inside the reaction vessel becomes too high, which is not preferred. The reaction after addition of water is preferably carried out at a temperature of 240° C. or higher for 20 minutes or more; if it is less than 20 minutes, the reaction does not proceed sufficiently and the degree of polymerization does not increase, 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.

[0024] 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.

Also, polyamide, polysulfone, polyphenylene oxide, polycarbonate, polyether sulfone, polyethylene terephthalate, polybutylene terephthalate, polyethylene, polypropylene, polytetrafluoroethylene, polyether ester elastomer, polyether amide elastomer, polyamideimide polyacetal, polyimide, etc. It is also possible to mix resins.

[0026]

EXAMPLES The present invention will be explained in more detail below using examples. In the following examples, a melt flow rate of 5 kg was used, and A was changed to 315.6°C.
Measured by the method of STM D-1238-70,
Values are expressed in g/10 minutes. Also, the reaction time is internal temperature 2
It is cooled from 10℃ to the maximum temperature of the reaction, and the internal temperature is 160℃.
This is the time it takes to reach ℃.

Example 1 In a 1-liter autoclave equipped with a stirrer, 245.0 g (1.02 mol) of sodium sulfide nonahydrate, 24.6 g (0.3 mol) sodium acetate, and 2.5 g of about 48% aqueous sodium hydroxide solution were added. (0.03 mol) and N-methyl-2
- 198 g (2.0 mol) of pyrrolidone was charged, and gradually heated to 205°C over about 3 hours while passing nitrogen through,
164 g of a distillate containing water as a main component was distilled out.

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. 210℃ to 27
The temperature was increased to 0°C at a rate of 0.6°C/min, and the temperature was increased to 30°C at 270°C.
After reacting for a minute, 18 g of water was added at a rate of 2 ml/min while cooling to 250° C. at a rate of 1° C./min.

After further reacting at 250°C for 20 minutes and cooling at a rate of 1°C/min, the contents were taken out and placed in N2 at 70°C.
- After washing once with 500 g of methyl-2-pyrrolidone,
It was washed six times with 700 g of water at 70°C and dried under reduced pressure at 120°C. The yield of the obtained polyphenylene sulfide was 86
%, the melt flow rate was 147 g/10 minutes. The reaction time was 270 minutes.

Example 2 After 30 minutes of reaction at 270°C, the reaction was continued for another 20 minutes while maintaining the temperature at 270°C while adding 18 g of water at a rate of 2 ml/min, and then at a rate of 1°C/min. The same operation as in Example 1 was performed except for cooling. The yield of the obtained polyphenylene sulfide was 86%, and the melt flow rate was 160 g/10 minutes. The reaction time is 2
It was 70 minutes.

Example 3 The same operation as in Example 1 was carried out, except that after the reaction was carried out at 270°C for 50 minutes, 18g of water was added at a rate of 2ml/min while cooling at a rate of 1°C/min. . The yield of the obtained polyphenylene sulfide was 87%, and the melt flow rate was 181 g/10 minutes. The reaction time was 270 minutes.

Example 4 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-
198 g (2.0 mol) of pyrrolidone was charged and heated in the same manner as in Example 1 to distill out 66 g of a distillate whose main component was water.

The reaction vessel was cooled to 180°C, and 146.3 g (0.995 mol) of p-dichlorobenzene and N-
149 g (1.5 mol) of methyl-2-pyrrolidone was added, the mixture was sealed under nitrogen gas pressure, and the temperature was raised to 210°C. Next 2
The temperature was raised to 10° C. at a rate of 0.6° C./min, and the reaction was carried out at 270° C. for 30 minutes. Then, while cooling to 250°C over 35 minutes, 18g of water was added at a rate of 2ml/min.
℃ to 1℃/min.

Thereafter, washing and drying were carried out in the same manner as in Example 1. The yield of the obtained polyphenylene sulfide was 85% and the melt flow rate was 178 g/10 minutes. The reaction time was 270 minutes.

Example 5 Polymerization was carried out using the same recipe as in Example 1, except that 155.9 g (1.0 mol) of p-dibromobenzene was used instead of p-dichlorobenzene. After the dehydration is completed, 21
Raise the temperature from 0℃ to 270℃ at a rate of 0.6℃/min.
Immediately after reaching the temperature, 18 g of water was added into the system over a period of 10 minutes using a high-pressure pump. Although the internal temperature decreased to 255°C, it was maintained at that temperature for 30 minutes, and after cooling to 120°C at a rate of 1°C/min, the contents were washed with N-methylpyrrolidone and water and dried. The resulting polymer had a yield of 83%, was in the form of granules, and had a melt flow rate of 160.

Comparative Example 1 When the temperature was raised after adding p-dichlorobenzene, the internal temperature was 21
The same operation as in Example 1 was performed except that 18 g of water was added at a rate of 2 ml/min when the temperature reached 0°C. The yield of the obtained polyphenylene sulfide was 65%, and the melt flow rate was 870 g/10 minutes. Moreover, the reaction time was 270 minutes.

Comparative Example 2 The same procedure as in Example 1 was carried out except that 90 g of water was added at a rate of 5 ml/min. The yield of the obtained polyphenylene sulfide was 87% and the melt flow rate was 190.
g/10 minutes. Further, the reaction time was 270 minutes.

Comparative Example 3 The same operation as in Example 1 was carried out except that the timing of adding water was changed after 20 minutes of reaction at 250°C. The yield of the obtained polyphenylene sulfide was 83% and the melt flow rate was 320 g/10 minutes. Moreover, the reaction time was 270 minutes.

Comparative Example 4 The same operation as in Example 1 was carried out except that sodium acetate was not used. The yield of the obtained polyphenylene sulfide was 78%, and the melt flow rate was 970 g/10 minutes. Further, the reaction time was 270 minutes.

Comparative Example 5 The same procedure as in Example 1 was carried out, except that the amount of p-dichlorobenzene was changed to 148.5 g (1.01 mol), the reaction was carried out at 270° C. for 170 minutes, and water was not added. I did this. The yield of the obtained polyphenylene sulfide was 80% and the melt flow rate was 220 g/10 minutes. Moreover, the reaction time was 400 minutes.

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, 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 15000 or less
10 50
00 or more 〃
20 3800
17500 ──────────
──────────────────────

004
2] Comparative Example 7 In polymerization using the same recipe as in Example 1, 18 g of water was added over 3 minutes after heating at 270° C. for 30 minutes. The internal temperature is 2
Although the temperature dropped to 45°C, the temperature was continued to cool at a cooling rate of 1°C/min, and the polymer was recovered and dried in the same manner as in Example 1. The yield was 81% and the melt flow rate was 197g/10
The minutes were shown. This polymer had lower molecular weight and yield than Example 1.

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)
820 730 Growth (%)
8
3.5 Weld strength (kg/cm2)
790 700
Bending strength (kg/cm2)
1451 1380 Impact strength No notch (kg・cm/
cm2)
49 23
──────────────────────────
─────────

All the polymers in the practical (comparative) examples had a glass transition temperature of 89 to 92°C and a melting point of 27.
It is estimated that the temperature is in the range of 5 to 295°C and has a polyphenylene sulfide structure as a repeating unit.

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). Moreover, molecular weight=108×degree of polymerization. Therefore, regarding the polymers obtained in each implementation (comparison) example,
Melt flow rates and molecular weights are tabulated below.

[Table 3]

As can be seen from the above table, the melt flow rate of the polymers obtained in Examples 1 to 5 of the present invention was low, indicating that the degree of polymerization of the polymers was high.

On the other hand, when water is added when the internal temperature is low as in Comparative Examples 1 to 7 (Comparative Example 1), when the reaction time after adding water is short at a predetermined temperature or higher (Comparative Example 3)
, when the alkali metal carboxylate is not present (Comparative Example 4), when the polymerization reaction temperature is less than 230 ° C. (Comparative Example 6),
When the polymerization reaction temperature is 240° C. or higher and the reaction time after hydrogenation is less than 20 minutes (Comparative Example 7), polyarylene sulfide with a high degree of polymerization cannot be obtained.

When a large amount of water is added (Comparative Example 2), a polymer with a high degree of polymerization can be obtained, but the pressure in the reaction system increases, making it necessary to improve the pressure resistance of the equipment, which is conversely economically disadvantageous. It will be disadvantageous. Also, if water is not added (
Comparative Example 5) In order to increase the degree of polymerization, the reaction time becomes longer, which is economically disadvantageous.

[0049]

[Effect of the invention] In conventional known examples, reaction conditions etc. were broadly set as general descriptions, but by controlling them to specific conditions as in the present invention, the polymerization time of polyarylene sulfide can be shortened. . It also has the effect of improving the yield of polyarylene sulfide obtained as a secondary product.

Claims (1)

[Claims] Claim 1: When a sulfur source selected from alkali sulfide, alkali hydrosulfide, and hydrogen sulfide is used in an organic polar solvent, and when a substance other than alkali sulfide is used as the sulfur source, an alkali metal hydroxide and a polyester are used. When using an alkali sulfide as the sulfur source, a method for obtaining polyarylene sulfide by reacting a halogenated aromatic compound with a polyhalogenated aromatic compound at a temperature of 230°C or higher in the latter half of the polymerization reaction. Add water with H2O
/polymer molar ratio was adjusted to 0.2 to 4.0 and heated at 240°C.
A method for producing polyarylene sulfide, which comprises reacting at a temperature above 20 minutes or more.