KR960005067B1 - Process for preparation polyarylene-sulfides - Google Patents

Abstract

The manufacturing process of polyarylene-sulfides takes advantage of the dehydration of alkali-sulfide hydrates by the addition of desiccant which makes the hydration rate higher and the molecular weight increased at the step of polymerization simultaneously. The desiccants, represented by (M)x(L)y, M- alkali metal or soil, L- transferable metal and organic atom's ion, x is an integer number 1-4, and y is 1 or 2, make the dehydration rate high enough to lower the reaction pressure and increase the number of polymers and the molecular weight. The process consists of the steps : adding desiccants to polarized solvents to dehydrate alkali-sulfides, using ployhalogen aromatic compounds to polymerize, and collecting the polymer from the alkali halogen compounds and drying it.

Description

Method for preparing polyarylene sulfide

The present invention relates to a method for producing polyarylene sulfide, and more particularly, to dehydration of an alkali metal sulfide by adding a dehydration aid to improve the dehydration efficiency to increase the polyarylene sulfide in the polymerization step. It relates to a manufacturing method.

Generally, polyarylene sulfide is widely used in special engineering plastics which require heat resistance and chemical resistance by molding in various ways. However, polymers used in such plastic applications have to be prepared with high viscosity because of low viscosity after polymerization and high difficulty in molding. In order to enhance the viscosity, a polymer having a viscosity crosslinked by heat treatment at a high temperature of 250 ° C. or higher is used. Arylene sulfide is prepared.

In addition, the polyarylene sulfide thus prepared has various physical properties such as tensile strength due to crosslinking of the molecular chain in the heat treatment process, so that it is prepared for use by adding other polymers, pigments, fillers, etc. Is the general way.

As a method of preparing such polyarylene sulfide, for example, an alkali metal sulfide such as sodium sulfide and a polyhalogen aromatic compound having two or more halogen elements such as p-dechlorobenzene, such as US Pat. No. 3,354,129, are contained in an organic polar solvent. There is a method to react in.

However, this method increases the polymerization pressure and lowers the molecular weight of the polymerized polyarylene sulfide in the process of dehydrating alkali metal sulfides in a nitrogen state without dehydration. It is not suitable as a polymer, crosslinking reaction by heat treatment is not easy, and there are problems that various physical properties are also reduced.

In addition, Japanese Patent Application Laid-Open No. 86-7332 discloses a two-phase reaction in a temperature range of 180 to 290 ° C in the presence of 0.5 to 7 moles of water with respect to 1 mole of an alkali metal sulfide, and has a melt viscosity of 1,000 poises. A method for producing the polyarylene sulfide as described above is provided. However, the method for producing such polyarylene sulfide is not industrially useful because the polymerization reaction is composed of two stages, the reaction time is long, and the reaction pressure is high.

Therefore, the inventors of the present invention have tried to overcome the problems of the conventional methods, as a result, in the manufacture of polyarylene sulfides by adding a dehydration aid when dehydrating the hydrate of the alkali metal sulfide, a large amount of water removal, reducing the reaction pressure and polymer New methods have been developed to increase the molecular weight of.

Therefore, in the present invention, in the preparation of polyarylene sulfide, the dehydration aid is added when dehydrating an alkali metal sulfide hydrate to increase the water removal efficiency for a predetermined time, thereby lowering the reaction pressure in the polymerization reaction, and It is an object of the present invention to provide an improved method for preparing polyarylene sulfide such that molecular weight is also increased.

Hereinafter, the present invention will be described in detail.

The present invention relates to a method for producing a polyarylene sulfide by reacting an alkali metal sulfide and a polyhalogen aromatic compound in an organic polar solvent, wherein the metal complex compound of the dehydration aid represented by the following formula when dehydrating the hydrate of the alkali metal sulfide It is characterized by a method for producing a polyarylene sulfide, which is added and dehydrated.

(M) x (L) y

In the formula, M represents an alkali or alkaline earth metal, L represents a complex ion of a transition metal and an organic element, x is an integer of 1 to 4, y is 1 or 2.

Referring to the present invention in more detail as follows.

The present invention provides a method for producing a polyarylene sulfide, in which a dehydration aid is added during dehydration of an alkali metal sulfide hydrate to distill the alkali metal sulfide hydrate so that a certain amount of hydrated water remains with respect to the alkali metal sulfide in a nitrogen state. In this case, the polyhalogen aromatic compound is characterized by a method of preparing a polyarylene sulfide having a moderately increased melt viscosity by polymerizing with increasing the polymerization temperature step by step.

In the present invention, the step of carrying out the process includes the steps of: first, dehydrating an alkali metal sulfide by adding a dehydrating aid to an organic polar solvent, second, a polymerization step using a polyhalogen aromatic compound, and third, recovering a polymer from an alkali metal halide. And drying.

In the present invention, as the dehydration aid, a metal complex compound is used as shown in the above general formula. Among the metal ions, [Ag (CN) ₂ ], [Cu (CN) ₃ ], [W (CN) ₈ ], [Co (CN) ₅ ], [Rh (CN) ₅ ], [Ir (CN) ₅ ], [Fe (CN) ₆ ], [Ni (CO) ₄ ], [Mn (CO) ₅ ], [Fe (CO) ₅ ], [Cr (CO) ₆ ], [Cu (NH ₃ ) ₄ ], [Rh (NH ₃ ) ₅ ], [Ir (NH ₃ ) ₅ ], [Pt (NH ₃ ) ₆ ], [SiF ₆ ], [ZrF ₇ ], [Nd (H ₂ 0) ₉ ] and the like or mixtures thereof, preferably K ₄ [Fe (CN) ₆ ], Na ₄ [Fe (CN ₆ ), Na ₂ [SiF ₂ ] or Na ₄ [Ni (CO) ₄ ].

In addition, the addition amount of the metal complex compound is preferably used in the range of 0.001 to 1% by weight relative to the alkali metal sulfide. If the content is less than 0.001% by weight, the dehydration aid effect of the metal complex does not occur. If the content exceeds 1% by weight, the metal complex may be difficult to remove in the process of removing impurities after obtaining the final polymer. It becomes a cause of reducing the physical property of a polymer.

In the present invention, the hydrate of an alkali metal sulfide such as sodium sulfide is distilled in a nitrogen state so that 0.6 mol to 0.75 mol of hydrated water remains in the alkali metal sulfide.

In the polymerization reaction of the present invention, the molar ratio of the alkali metal compound is preferably 0.8 to 1.5 moles, preferably 0.9 to 1.3 moles, per 1 mole of the dihalogenated aromatic compound.

If the molar ratio is less than 0.8 or more than 1.5, it is difficult to obtain industrially useful polyarylene sulfide.

In addition, when using a branching agent together, the compounding molar ratio with respect to a dihalogen aromatic compound is 0.001-0.05 normally, Preferably it is 0.001-0.03. If the molar ratio is less than 0.001, polymerization of the polyarylene sulfide may not be achieved, and gelation may occur during polymerization in which the molar ratio is greater than 0.05, thereby making it impossible to produce a moldable polyarylene sulfide.

As for the usage-amount of an organic polar solvent, 150-1,000 g of use is preferable with respect to 1 mol of alkali metal sulfides normally.

The polymerization reaction is usually carried out at a temperature range of 180 to 330 ° C, preferably 210 to 290 ° C. If the reaction temperature is lower than 180 ° C, the rate of polymerization reaction is not sufficient, and if the reaction temperature is higher than 330 ° C, it may cause side reactions or cause decomposition of the produced polymer or deterioration of the organic polar solvent, resulting in deterioration of the quality of the polyarylene sulfide. have.

The reaction time of the polymerization reaction is usually within 20 hours, particularly preferably 0.5 to 7 hours. After completion of the polymerization reaction, the polyarylene sulfide may be fractionated directly from the reaction solution by standard methods such as filtration or centrifugation, or may be obtained by fractionating from the reaction solution after adding acid with water or dilution. The filtration process is followed by rinsing with water to generally remove inorganic constituents that may adhere to the polymer. In addition to or after this washing step, washing or extraction using other washing liquids such as N-methylpyrrolidone, acetone and methanol can be performed. The solvent is separated from the reaction vessel and then washed as described above to recover the polymerizer.

Polyarylene sulfide prepared by the method of the present invention can adjust the viscosity by heat treatment, it can be processed into plastic by injection molding and extrusion molding.

On the other hand, such polyarylene sulfide may be used by adding various kinds of additives to the polymer as needed in plastic processing.

Representative examples of the additives include ceramic fibers, such as glass fibers, carbon fibers and alumina fibers, metal fibers, and calcium titanate, mica, silica, barium sulfate, calcium sulfate, kaolin, calcium silicate, magnesium carbonate, antimony trioxide, and oxides. Zinc, titanium oxide, magnesium oxide, iron oxide, molybdenum disulfide, graphite, gypsum, glass powder, quartz, silicon glass and organic or inorganic stabilizers can be used.

In addition, other participating agents that may be mixed may include silane-based release agents such as aromatic hydroxy derivatives or titanic acid-based coupling agents, lubricants, thermal stabilizers, weathering agents, foaming agents, corrosion inhibitors, ion barrier agents, flame retardants and flame retardants. Also, homopolymers, random or block copolymers and graft polymers can be mixed with polyarylene sulfides alone or as a mixture thereof.

The present invention as described above is a method for producing a polyarylene sulfide, characterized in that the dehydration aid is added to the hydrate of the alkali metal sulfide, polyarylene sulfide prepared by the method of the present invention (1) the same time as conventional During the dehydration step, the dehydration efficiency in the present invention is high, so that the amount of water removal in the hydrate of alkali metal sulfide is large, and (2) the reaction pressure in the subsequent polymerization reaction after the dehydration step is reduced compared to the conventional one, (3) Compared to the dehydration process according to the conventional method, the polymer may have high molecular weight, low oligomer content, and may be widely used in special engineering plastics requiring heat resistance and chemical resistance by molding in various ways.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the Examples.

The logarithmic viscosity (IV) of the example is a value measured at a load of 2160 g at 305 ° C. at a concentration of 0.4 g / L at 205 ° C. using 1-chloronaphthalene as a solvent.

Example 1

Into an internal pressure 1.7L reactor equipped with a stirrer and a dehydration tower, 255.9 g (2.0 mol) of sodium sulfide, 0.04 g of potassium ferrocyanide trihydrate, and 500 ml of N-methylpyrrolidone (NMP) were added and nitrogen-substituted.

Under nitrogen stream, 76 g of water and 8 g of NMP were distilled off while the contents of the pressure reactor were heated up and heated at 160 ° C. for 1 hour, and then heated up to 205 ° C. for distillation. After cooling the internal temperature of the pressure reactor to 170 ° C., a solution obtained by dissolving 294.0 g of p-diclobenzine in 300 ml of NMP was added to the dehydrated product, the pressure reactor was sealed, and the temperature was raised to 250 ° C. to carry out polymerization for 3 hours. It was. At this time, the reaction pressure was 5.0 kgf / cm ² .

After the completion of the reaction, the reaction mixture was cooled to around room temperature, the lid was opened, and the slurry-like reaction product was taken out. The reaction product was washed twice with 2 L of water, and then dried at a temperature of 120 ° C. in a vacuum. The logarithmic viscosity (IV) of the obtained polyphenylene sulfide was 0.20, and MI was 360 g / 10min.

Example 2

The same procedure as in Example 1 was carried out except that the potassium ferrocyanide trihydrate was changed to 0.12 g. 73 g of water was released during the dehydration process, and the polymerization pressure was 5.1 kgf / cm ² . IV of obtained polyphenylene sulfide was 0.19, and MI was 400 g / 10min.

[Comparative Example]

The same process as in Example 1 was carried out except that potassium ferrocyanide was not added in Example 1. In the dehydration process, 64 g of water and 15 g of NMP were leaked, and the reaction pressure was 6.9 kgf / cm ² . The IV of this polymer was 0.16 and the MI was 1040 g / 10 min.

[Examples 3-5]

It carried out similarly to Example 1 except having changed the dehydration aid in the said Example 1. The amount of water in the dehydration process, the polymerization pressure, and the IV of the prepared polymer are shown in Table 1 below.

Experimental Example

The oligomer content of the polyphenylene sulfide obtained by the method of Examples 1 to 5 and Comparative Example was measured. Determination of the oligomer content was calculated by dissolving and extracting the oligomer of each polymer for 12 hours in a dichloromethane solvent, using a Soxhlet apparatus. The measurement results are shown in Table 1 below.

TABLE 1

Claims (3)

In the method for producing polyarylene sulfide by reacting an alkali metal sulfide and a polyhalogen aromatic compound in an organic polar solvent, when the hydrate of the alkali metal sulfide is dehydrated by adding a metal complex compound of a dehydration aid represented by the following formula Method for producing a polyarylene sulfide, characterized in that. (M) x (L) y In the above formula, M represents an alkali or alkaline earth metal, L represents a complex ion of a transition metal and an organic element, x is an integer of 1 to 4, y is 1 or 2. The metal complex compound of claim 1, wherein the metal complex of the dehydrating aid is K ₄ [Fe (CN) ₆ ], Na ₄ [Fe (CN) ₆ ], Na ₂ [SiF ₂ ] or Na ₄ [Ni (CO) ₄ ] Method for producing a polyarylene sulfide, characterized in using any one or more of. The method for producing polyarylene sulfide according to claim 1, wherein the amount of the metal complex compound of the dehydrating aid is used in an amount of 0.001 to 1% by weight based on the alkali metal sulfide.