KR20200136316A - Method for preparing polyarylene sulfide - Google Patents

Abstract

The present invention provides a method for producing a polyarylene sulfide having excellent processability and improved kneading property with glass fibers used in a compounding composition by increasing the amount of carboxyl groups introduced at a terminal of a polyarylene sulfide and decreasing the residual content of sodium through the control of a polymerization process and washing process in the production of a polyarylene sulfide.

Description

Method for producing polyarylene sulfide TECHNICAL FIELD [METHOD FOR PREPARING POLYARYLENE SULFIDE]

The present invention provides excellent processability by increasing the amount of carboxyl group introduced at the end of the polyarylene sulfide and reducing the residual content of sodium cation (Na ⁺ ) through control of the polymerization process and washing process when producing polyarylene sulfide. It relates to a method for producing polyarylene sulfide having improved kneading properties with glass fibers used in a compounding composition.

Polyarylene sulfide (PAS), represented by polyphenylene sulfide (PPS), has excellent strength, heat resistance, flame retardancy and workability. It is widely used as a material replacing the same die casting metal. In addition, since PPS has good fluidity, it is advantageous to use as a compound by kneading it with a filler or reinforcing agent such as glass fiber.

Typically, PAS is prepared through a polymerization reaction between a sulfur source and a dihalogenated aromatic compound in the presence of a polar organic compound such as N-methyl-2-pyrrolidone (NMP), and in the polymerization reaction, a molecular weight modifier such as an alkali metal salt is Optionally, it may be used further. When preparing PAS through the above method, the reaction product obtained as a result of the polymerization reaction includes an aqueous phase and an organic phase, and the PAS produced is mainly dissolved and contained in the organic phase. Accordingly, a process for separating the generated PAS is additionally performed, and a method of depositing PAS by cooling the reaction product is mainly used.

In the case of polyphenylene sulfide (PPS), after completion of the polymerization, it is diluted with water or obtained as a solid through a washing process using water and an aqueous solvent as a slurry, a filtration process, and a drying process. However, since the PPS obtained by this method exhibits high hydrophobicity, when kneading with glass fibers for the production of compound products, it exhibits low kneading properties, deteriorating the mechanical properties of the compound product, and is not easy to melt processing. there is a problem.

As a method to solve such a problem, a method of introducing a carboxyl group into PPS using a monomer containing a carboxyl group such as chlorobemzoic acid in the polymerization of PPS has been proposed, but in this case, the crystallinity of PPS is reduced and , It may adversely affect the physical properties.

Accordingly, there is a need for research and development on a method of producing polyarylene sulfide having excellent processability and excellent kneading property with glass fibers used in compounding compositions.

An object of the present invention is to increase the amount of carboxyl group introduced at the end of the polyarylene sulfide and reduce the Na ⁺ residual content, thereby producing a polyarylene sulfide having excellent processability and excellent kneading property with glass fibers used in a compounding composition. To provide a way.

According to an embodiment of the present invention,

Reacting an alkali metal hydrosulfide and an alkali metal hydroxide in a mixed solvent of water and an amide compound to prepare a sulfur source including an alkali metal sulfide and a mixed solvent of the water and the amide compound;

Preparing a mixture by adding a dihalogenated aromatic compound and an amide compound to the sulfur source, and performing a polymerization reaction to prepare a polyarylene sulfide-containing slurry; And

Including; washing the slurry containing the polyarylene sulfide,

The dihalogenated aromatic compound is added in a molar ratio of more than 1 and not more than 1.07 with respect to 1 mol of the alkali metal hydrosulfide,

The washing is, for the polyarylene sulfide-containing slurry, a first washing using an amide compound at a temperature of 80°C or higher and 180°C or lower, a second washing using water, and an acid containing acid at a concentration of 0.3% by weight or more. It provides a method for producing polyarylene sulfide, which is performed in the order of a third washing using an aqueous solution and a fourth washing using water of 70° C. or higher.

According to the production method of the present invention, the amount of carboxyl group introduced at the end of the polyarylene sulfide to be produced is increased, and the residual content of Na ⁺ is reduced, so that it has excellent processability and improved kneading property with glass fibers used in the compounding composition. Can be indicated. As a result, when injection molding using the compounding composition to which the polyarylene sulfide is applied, the mechanical strength of the manufactured injection molded product can be improved and color change can be minimized, so that the polyarylene sulfide is used in automobiles, electrical and electronic products, or It may be useful in the manufacture of a molded article for metal replacement in a mechanical part, particularly in the manufacture of a reflector or base plate for automobile lamps where excellent mechanical properties are required.

1 is a flowchart schematically illustrating a washing process for a slurry containing polyphenylene sulfide in Example 1. FIG.
FIG. 2 is a process chart schematically showing a washing process for a slurry containing polyphenylene sulfide in Comparative Example 1. FIG.
3 is a graph showing the relationship between Na ⁺ residual content (Na contents, ppm) and carboxy group peak ratio (-COOH peak ratio) in polyphenylene sulfide.
4 is a graph showing the relationship between the Na ⁺ residual content in polyphenylene sulfide and the reactivity (PPS reactivity) of polyphenylene sulfide.

In the present invention, terms such as first and second are used to describe various components, and the terms are used only for the purpose of distinguishing one component from other components.

In addition, terms used in the present specification are only used to describe exemplary embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as "comprise", "include" or "have" are intended to designate the presence of implemented features, numbers, steps, components, or a combination thereof, and one or more other features or It is to be understood that the possibility of the presence or addition of numbers, steps, elements, or combinations thereof is not preliminarily excluded.

In addition, the present invention is a bar that can add various changes and have various forms, and will be described in detail below and exemplifying specific embodiments. However, this is not intended to limit the present invention to a specific form disclosed, it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

Hereinafter, a method for preparing polyarylene sulfide according to an embodiment of the present invention, and a polyarylene sulfide prepared according to the present invention will be described in more detail.

A method for producing polyarylene sulfide according to an embodiment of the present invention,

A step of reacting an alkali metal hydrosulfide and an alkali metal hydroxide in a mixed solvent of water and an amide compound to prepare a sulfur source including an alkali metal sulfide and a mixed solvent of the water and amide compound (step One);

Preparing a mixture by adding a dihalogenated aromatic compound and an amide compound to the sulfur source and performing a polymerization reaction to prepare a polyarylene sulfide-containing slurry (step 2); And

Including; washing the slurry containing the polyarylene sulfide (step 3),

The dihalogenated aromatic compound is added in a molar ratio of more than 1 and 1.07 or less with respect to 1 mol of the alkali metal hydrosulfide,

The washing is, for the polyarylene sulfide-containing slurry, a first washing using an amide compound at a temperature of 80°C or higher and 180°C or lower, a second washing using water, and an acid containing acid at a concentration of 0.3% by weight or more. It is performed in the order of the third washing using an aqueous solution and the fourth washing using water of 70° C. or higher.

The present invention controls the use of dihalogenated aromatic compounds and alkali metal hydrosulfides as raw materials during the polymerization process for the production of polyarylene sulfide, and controls the order and concentration of washing liquid in the washing process after polymerization is completed. , In the polyarylene sulfide to be prepared, the amount of hydrophilic carboxyl group introduced at the terminal may be increased, and the residual content of sodium cation (Na ⁺ ) may be decreased. As a result, processability of the polyarylene sulfide can be improved, and kneading properties with glass fibers used in the compounding composition can be improved. In addition, due to the improved processability, the melt processing conditions can be variously changed, and the reactivity with the coupling agent is improved during compounding with the glass fiber, so that the physical properties of the final compound product can be improved.

Hereinafter, a method of preparing polyarylene sulfide according to an embodiment of the present invention will be described for each step.

First, step 1 for preparing polyarylene sulfide is a step of preparing a source of sulfur used for polymerization of polyarylene sulfide.

Specifically, step 1 may be performed by dehydrating an alkali metal hydrosulfide and an alkali metal hydroxide in a mixed solvent of water and an amide compound. The sulfur source generated as a result of the reaction as described above includes a sulfide of an alkali metal generated by the reaction of the hydroxide of the alkali metal and the hydroxide of the alkali metal, and the mixture of water remaining after the reaction and an amide compound Contains a solvent.

The alkali metal sulfide may be determined according to the type of alkali metal hydrosulfide used in the reaction. Specifically, the sulfide of the alkali metal may be lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide or cesium sulfide, and any one or a mixture of two or more of them may be included.

In addition, examples of the alkali metal hydrosulfides that can be used in the preparation of the alkali metal sulfide include lithium hydrogen sulfide, sodium hydrogen sulfide, potassium hydrogen sulfide, rubidium hydrogen sulfide, cesium hydrogen sulfide, etc., and anhydrides or hydrates thereof may be used. Any one or a mixture of two or more of the compounds exemplified above may be used.

In addition, specific examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, or cesium hydroxide, and any one or a mixture of two or more of them may be used. The alkali metal hydroxide may be used in an equivalent ratio of 0.90 or more, or 1.0 or more, 2.0 or less, or 1.5 or less, or 1.2 or less with respect to 1 equivalent of the alkali metal hydrosulfide.

Meanwhile, in the present invention, the equivalent means a molar equivalent (eq/mol).

In addition, when preparing the sulfur source by the reaction of the alkali metal hydroxide and the alkali metal hydroxide, an organic acid salt of an alkali metal may be optionally further added as a polymerization aid. The organic acid salt of the alkali metal can then accelerate the polymerization reaction to increase the degree of polymerization of the polyarylene sulfide within a short time. The organic acid salt of the alkali metal may specifically be lithium acetate or sodium acetate, and any one or a mixture of two or more of them may be used. The organic acid salt of the alkali metal may be used in an equivalent ratio of 0.01 or more, or 0.05 or more, 1.0 or less, or 0.8 or less, or 0.5 or less with respect to 1 equivalent of hydrosulfide of the alkali metal.

In addition, the reaction of the alkali metal hydrosulfide and the alkali metal hydroxide may be carried out in a mixed solvent of water and an amide-based compound. In this case, specific examples of the amide-based compound include N,N-dimethylformamide or N, Amide compounds such as N-dimethylacetamide; Pyrrolidone compounds such as N-methyl-2-pyrrolidone (NMP) or N-cyclohexyl-2-pyrrolidone; Caprolactam compounds such as N-methyl-ε-caprolactam; Imidazolidinone compounds such as 1,3-dialkyl-2-imidazolidinone; Urea compounds such as tetramethyl urea; Or phosphoric acid amide compounds such as hexamethylphosphoric acid triamide, and the like, and any one or a mixture of two or more of them may be used. Among these, N-methyl-2-pyrrolidone (NMP) may be more preferably used when considering the increase in reaction efficiency and the effect of a co-solvent as a polymerization solvent during polymerization for the production of polyarylene sulfide.

In addition, water in the mixed solvent may be used in an equivalent ratio of 1 or more, 1.5 or more, or 2 or more, 8 or less, or 5 or less, or 4 or less with respect to 1 equivalent of the amide compound.

As a result of the reaction of the alkali metal hydrosulfide and the alkali metal hydroxide as described above, the alkali metal sulfide is precipitated as a solid in a mixed solvent of water and an amide compound. Accordingly, when the sulfur source produced by reacting the above-described alkali metal hydrosulfide and alkali metal hydroxide is used as the sulfur source in the production of the polyarylene sulfide according to the present invention, the molar ratio of the sulfur source is the alkali metal introduced during the reaction. It is taken as the molar ratio of hydrosulfide of

Meanwhile, after the reaction of the alkali metal hydroxide and the alkali metal hydroxide is completed, a dehydration process for removing a solvent such as water contained in the reaction product may be performed. Accordingly, the manufacturing method according to an embodiment of the present invention may further include performing a dehydration process on the reaction product after completion of the reaction between the alkali metal hydrosulfide and the alkali metal hydroxide. The dehydration process may be performed according to a method well known in the art.

During the dehydration process, a part of the amide compound is distilled and discharged together with the solvent in the reaction product, specifically water. In addition, some sulfur contained in the sulfur source may react with water due to heat during the dehydration process to generate hydrogen sulfide and alkali metal hydroxide, and the generated hydrogen sulfide may be volatilized as a gas. Accordingly, the amount of sulfur in the sulfur source remaining in the system after the dehydration process may be reduced. For example, in the case of using a sulfur source containing alkali metal hydrosulfide as a main component, the amount of sulfur remaining in the system after the dehydration process is the value obtained by subtracting the molar amount of hydrogen sulfide volatilized out of the system from the amount of sulfur present in the introduced sulfur source. same. Accordingly, it is necessary to quantify the amount of effective sulfur contained in the sulfur source remaining in the system after the dehydration process from the amount of hydrogen sulfide volatilized out of the system. Accordingly, when the manufacturing method according to an embodiment of the present invention further includes a dehydration process, the dehydration process may be performed until the water is at least 1.5 molar ratio and less than 3.5 molar ratio to 1 mol of effective sulfur. In addition, when the amount of water in the sulfur source is excessively reduced by the dehydration process, a step of controlling the amount of water by adding water prior to the polymerization process may be optionally further performed.

The sulfur source prepared through the reaction of an alkali metal hydrosulfide and an alkali metal hydroxide as described above and a selective dehydration process may include a mixed solvent of water and an amide-based compound together with the alkali metal sulfide, The water may be included in a specific ratio of 1.5 molar or more, 3.5 molar ratio or less, or 2.0 molar ratio or less with respect to 1 mol of sulfur contained in the sulfur source. In addition, the amide-based compound may be contained in a molar ratio of 1 or more, 3.5 molar ratio or less, 3.45 molar ratio or less, or 2.0 molar ratio or less with respect to 1 mol of sulfur contained in the sulfur source. In addition, the sulfur source may further include a hydroxide of an alkali metal produced by the reaction of sulfur and water.

Next, step 2 for preparing polyarylene sulfide is a step of polymerizing a sulfur source prepared in step 1 with a dihalogenated aromatic compound to prepare a polyarylene sulfide-containing slurry.

Specifically, step 2 may be carried out by adding and mixing a dihalogenated aromatic compound and an amide compound to the sulfur source prepared in step 1 to prepare a mixture, followed by polymerization.

The dihalogenated aromatic compound usable for the production of the polyarylene sulfide is a compound in which two hydrogens in the aromatic ring are substituted with halogen atoms such as fluorine, chlorine, bromine or iodine. Specific examples include o-dihalobenzene, m-dihalobenzene, p-dihalobenzene, dihalotoluene, dihalonaphthalene, dihalobiphenyl, dihalobenzoic acid, dihalodiphenyl ether, dihalodiphenylsulfone, dihalodiphenyl Sulfoxide or dihalodiphenyl ketone, and the like, and any one or a mixture of two or more of them may be used. Among them, para-dichlorobenzene (p-DCB) may be used in consideration of the reactivity and the effect of reducing the generation of side reactions when preparing polyarylene sulfide.

The dihalogenated aromatic compound may be added in a molar ratio of more than 1 and not more than 1.07 with respect to 1 mol of the alkali metal hydrosulfide. When added within the above content range, polyarylene sulfide having excellent physical properties can be prepared without fear of lowering the melt viscosity of the prepared polyarylene sulfide and increasing the chlorine content present in the polyarylene sulfide. have. However, outside the above content range, when the amount of the dihalogenated aromatic compound added is 1 mole ratio or less with respect to 1 mole of the alkali metal hydrosulfide, the production yield of polyarylene sulfide is 80% or less, specifically up to 70% or less. It is not preferable because it is greatly reduced, and when the amount of the dihalogenated aromatic compound added exceeds 1.07 molar ratio with respect to 1 mol of the hydrosulfide of the alkali metal, the viscosity of the polyarylene sulfide to be produced is greatly reduced, and thus the melt flow rate Measurement is impossible. Considering the excellence of the improvement effect by controlling the sulfur source and the amount of the dihalogenated aromatic compound added, more specifically, the dihalogenated aromatic compound is 1.02 or more, or 1.04 or more, and 1.07 or less, or 1.06 or less, or 1.05 or less. Can be put in.

In addition, since the dihalogenated aromatic compound is easily vaporized at a high temperature, the manufacturing method according to an embodiment of the present invention includes the temperature of the reactor including the sulfur source before the second step, that is, before the addition of the dihalogenated aromatic compound. The step of lowering to a temperature range of 200° C. or less, 180° C. or less, or 170° C. or more, and 150° C. or more may be optionally further included.

The polymerization reaction of the dihalogenated aromatic compound and the sulfur source prepared in Step 1 may be performed in a solvent of an amide-based compound that is stable against alkali at high temperature as an aprotic polar organic solvent.

Specific examples of the amide compound are as described above, and when considering excellent reaction efficiency among the exemplified compounds, N-methyl-2-pyrrolidone (NMP) or N-cyclohexyl-2-pyrrolidone A pyrrolidone-based compound such as may be more preferable.

In addition, since the amide-based compound added in step 2 may function as a co-solvent in the amide-based compound included in the sulfur source prepared in step 1, the amide-based compound added in the polymerization reaction system, that is, the sulfur source prepared in step 1 The molar ratio of water (H ₂ O) to the amide compound present in the mixture prepared by mixing after the addition of the halogenated aromatic compound and the amide compound (the molar ratio of H ₂ O/amide compound) is less than 0.85. Can be added in amounts.

Specifically, the amide-based compound is water (H ₂ O) per 1 mol of sulfur (S) in a mixture prepared by adding a dihalogenated aromatic compound and an amide compound to the sulfur source prepared in step 1 and mixing ) Of (molar ratio of H ₂ O/S) is 1.5 or more, or 1.7 or more, or 1.9 or more, 3.5 or less, or 3 or less, or 2 or less, and the molar ratio of the amide compound to 1 mol of sulfur (S) It may be added in an amount such that (the molar ratio of the amide compound/S) is 1 or more, or 2 or more, and 3.5 or less, or 3.4 or less. When added under the above conditions, polyphenylene sulfide can be prepared in an excellent yield, and at the same time, the content of unreacted raw materials and by-products can be reduced.

In addition, with respect to the mixture, an additive for controlling the polymerization reaction or the molecular weight of the polymer, such as a molecular weight modifier or a crosslinking agent, may be further added in an amount within a range that does not lower the physical properties and production yield of the finally produced polyarylene sulfide. have.

Next, the polymerization reaction in the mixture containing the sulfur source and the dihalogenated aromatic compound may be performed at a temperature of 200°C or higher, or 250°C or higher, and 300°C or lower or 270°C or lower. When performed in the above temperature range, polyarylene sulfide can be produced with excellent efficiency, and at the same time, the amount of unreacted raw materials and side reaction products can be reduced.

The reaction product produced as a result of the polymerization reaction in step 2 as described above is obtained as a slurry in which polyarylene sulfide is dissolved.

Next, Step 3 is a step of separating and purifying the polyarylene sulfide by washing the polyarylene sulfide-containing slurry obtained in Step 2.

Specifically, the washing process in step 3 is, for the polyarylene sulfide-containing slurry obtained in step 2, the first washing using an amide compound at a temperature of 80°C or more and 180°C or less, and the second washing with water. Washing, the third washing using an acidic aqueous solution containing an acid at a concentration of 0.3% by weight or more, and the fourth washing using water, and the washing process in each washing step may be repeated two or more times each. I can.

As described above, in the manufacturing method according to an embodiment of the present invention, the washing process is performed in multiple steps of at least four steps. In addition, in the washing process, unlike a conventional method in which an acid washing process is performed after washing using an organic solvent, a second washing process using water is performed immediately before the third washing process using the acid aqueous solution. As the washing process using water is performed prior to the pickling process as described above, the residual content of sodium cations remaining in the polyarylene sulfide can be greatly reduced, and as a result, introduced when introducing a carboxy group through the subsequent pickling process. This becomes easier and the amount of introduction can be increased. In addition, the amount of introduction can be easily controlled by controlling the acid concentration used during pickling.

In addition, after the acid washing step of the polyarylene sulfide-containing slurry, since the fourth washing process using water is performed at least once to neutralize the unreacted acid, after the acid washing process, an organic solvent is additionally used. You don't have to use it.

Specifically, in the manufacturing method according to an embodiment of the present invention, the first washing may be performed through a washing process using an amide compound.

As the amide compound, compounds as described above, such as N-methyl-2-pyrrolidone (NMP), may be used, and more specifically, it is preferable to use the same compound as the amide compound used in the polymerization reaction. I can.

Usually, when washing for separation and purification of polyarylene sulfide, organic compounds such as ketone, nitrile, and alcohol are used, but in the present invention, by using the same compound as the amide compound used in the polymerization reaction, , It is easy to remove unreacted raw materials, and a separate process for separating and removing heterogeneous organic solvents is unnecessary.

In the first washing, the amide compound may be used in a volume ratio of 5 times or more and 7 times or less with respect to the total volume of the polyarylene sulfide-containing slurry. If the amount is less than 5 times, it is difficult to exhibit a sufficient cleaning effect, and if it exceeds 7 times, there is a risk of re-dissolution of the produced polyarylene sulfide.

In addition, the first washing process may be performed at a temperature of 80°C or more, or 120°C or more, and 180°C or less, or 170°C or less, or 150°C or less. Conventionally, the washing process using an organic solvent such as NMP or ketone is performed at a temperature range of 100° C. or less, specifically 50 to 80° C., whereas the washing process using an amide compound in the present invention has high Due to the boiling point, it is easier to clean low molecular weight PPS or oligomer by performing in a higher temperature range than the conventional one. If the temperature during the first washing process is less than 80°C, there is a risk of deterioration of the cleaning effect, and if it exceeds 180°C, the pressure in the reaction system increases significantly, and the polyarylene sulfide produced is not preferable because it is dissolved in the amide compound. not.

Next, after the first washing process using the amide-based compound, a second washing process using water is performed.

Through washing with water, water-soluble by-products remaining in the slurry, particularly a large amount of NaCl and residual organic solvents, can be removed.

The water may be clean water, distilled water, deionized water, ultra-pure water (18.2 Mohm or more, tertiary water), or ultra-hyper pure water; 25 Mohm or more, Quaternary water) and the like may be used, among which distilled water or deionized water may be preferable.

The second washing process using water may be performed at a temperature of 70° C. or more, or 80° C. or more, and less than 100° C., or 90° C. or less. When the temperature is less than 70° C. during the secondary washing, it is difficult to obtain a sufficient washing effect, and when the temperature is higher than 100° C., the washing effect may be reduced due to evaporation of the washing water. In addition, the second washing process may be preferably performed at a lower temperature than the first washing process. By performing at a lower temperature than the first washing process, it is possible to increase the removal effect by increasing the solubility of water-soluble by-products remaining in the slurry.

Next, after completion of the second washing process, a third washing process using an aqueous acid solution is performed.

As the acid, a carboxylic acid such as acetic acid may be used, and among them, acetic acid may be more preferable in terms of ease of use and washing effect.

In addition, the amount of the carboxyl group introduced into the polyarylene sulfide can be controlled by controlling the concentration of the acid used during the pickling. An effect to be realized in the present invention, that is, a silane-based system determined according to Equation 1 to be described later The reactivity with the coupling agent is 2 or more, and further, the melt flow index (measured under the conditions of 315°C, 4 minutes, 5 kg according to ASTM-D1238-70) is 200 g/10min or more and 1000 g/10min or less, and Na ^{+ For the} production of polyarylene sulfide having a residual content of 100 ppm or less, the acid content is 3% by weight or more, more specifically 4% by weight or more, 7% by weight or less, or 5% by weight or less based on the total weight of the acid aqueous solution. I can. If the acid content is less than 3% by weight, the Na ⁺ residual content increases, the reactivity to the coupling agent decreases due to a decrease in the amount of carboxyl groups introduced into the polyarylene sulfide, and the kneading property with the glass fiber may decrease. .

In addition, the pickling process may be performed at a temperature of 50° C. or more, or 70° C. or more, and 100° C. or less, or 90° C. or less. When the temperature condition during the pickling is less than 50°C, the washing effect may be deteriorated, and when it exceeds 100°C, there is a risk that a large amount of acid may be evaporated after the injection. In addition, the pickling process may be performed for 15 minutes or more, or 30 minutes or more, and 60 minutes or less in the above temperature range. In addition, if the acid washing time is 15 minutes or less, sufficient washing cannot be performed, and the reaction time between the polyarylene sulfide and the acid is not sufficient, so that the amount of carboxyl group introduced into the polyarylene sulfide may decrease, and 60 minutes may be If it is exceeded, the entire manufacturing process of polyarylene sulfide becomes longer due to an increase in washing time.

Next, after the third washing process, a fourth washing process using water is performed.

The fourth washing process is for removing unreacted acid remaining in the acid used in the third washing process as described above, and is performed at least once or twice or more at a temperature of 70°C or higher or 80°C or higher. In consideration of fairness and cleaning efficiency, it may be performed twice or three times at a temperature of 70° C. or more, or 80° C. or more, and less than 100° C., or 90° C. or less. When performed in the above temperature range, unreacted reactants and impurities contained in the polyarylene sulfide can be removed with excellent efficiency without evaporation of the washing water, and in particular, the Na ⁺ residual content can be reduced.

If the water temperature in the fourth washing process is less than 70°C, the acid removal efficiency is low, so the content of residual acid in the polyarylene sulfide may increase, and as a result, the reactivity, specifically, with the silane-based coupling agent, decreases. Can be.

Meanwhile, each of the above-described washing processes may be performed in a washing tank, and a washing tank used in the pickling process may be connected to and installed with a separate transfer line into which an aqueous acetic acid solution can be injected.

After completion of the washing process, polyarylene sulfide may be recovered through a drying process. The drying process may be performed by a method well known in the art, and the conditions are not limited thereto.

By the production method as described above, the amount of carboxyl group introduced at the terminal is increased and the residual content of sodium cation is decreased, together with the MFR of the optimum range, so that polyarylene sulfide exhibiting excellent processability can be produced in high yield.

Specifically, the polyarylene sulfide has a melt flow index of 200 g/10min or more, or 400 g/10min or more, or 450 g/10min, measured under the conditions of 315°C, 4 minutes, and 5kg according to ASTM-D1238-70. Or more, or 470 g/10min or more, 1000 g/10min or less, 800 g/10min or less, or 600 g/10min or less.

In addition, the polyarylene sulfide may exhibit excellent reactivity to a silane-based coupling agent by increasing the amount of carboxyl group introduced and decreasing the amount of Na ⁺ residual. Specifically, the polyarylene sulfide may have a reactivity of 2 or more, or 2.05 or more, or 2.09 or more, or 2.10 or more, with a silane-based coupling agent determined according to Equation 1 below. At this time, the silane-based coupling agent may be used without particular limitation as long as it is a silane-based compound commonly used as a coupling agent. For example, in the present invention, gamma-glycidoxypropyltrimethoxysilane marketed as Silquest A-187™ was used. .

[Equation 1]

Reactivity = MFR _PPS / MFR _{PPS_CA reactant}

In Equation 1, MFR _PPS is the melt flow rate of the polyarylene sulfide itself, and the MFR _{PPS_CA reactant} is the melt flow rate of the reactant obtained as a result of the reaction between the polyarylene sulfide and the silane-based coupling agent. The flow rate is a value measured at 315°C, 4 minutes, and 5kg according to ASTM-D1238-70.

In addition, in Equation 1, the melt flow rate of the reactant obtained as a result of the reaction between the polyarylene sulfide and the silane-based coupling agent is specifically 180 g/10 min or more, or 200 g/10 min or more, or 210 g/10min or more, 270 g/10min or less, or 260 g/10min or less, or 250 g/10min or less, or 245 g/10min or less.

In addition, polyarylene sulfide prepared according to the above-described manufacturing method has a low residual acid content due to the water washing process after the acid washing process. The residual acid content in the polyarylene sulfide can be determined from the pH value of the distilled water obtained by placing the prepared polyarylene sulfide in distilled water at room temperature or at a temperature of 18 to 25°C, stirring for 3 days, and filtering. The lower the residual acid content is, the less acid-induced decomposition reaction occurs, which means that it has excellent reactivity.

Specifically, the polyarylene sulfide prepared according to the above manufacturing method has a pH of 6 or more, or 6 or more and 8 or less, or 6 or more, after being immersed in distilled water at room temperature or 18 to 25°C for 3 days. 7 or less, or a neutral pH of 7. If the pH of the distilled water immersed in polyarylene sulfide is less than 6, the residual acid concentration in the polyarylene sulfide is high, and the reactivity is greatly reduced. In addition, when the pH of the immersion distilled water exceeds pH 8 and exhibits basicity, the acid treatment is insufficient, so that the Na at the end group has little substitution effect, resulting in reduced reactivity.

In addition, the polyarylene sulfide has a low sodium cation (Na ⁺ ) residual content of 100 ppm or less, or 95 ppm or less. The lower the Na ⁺ residual content is, the more preferable, but may be at least 10 ppm or more, or 30 ppm or more, or 50 ppm or more, or 65 ppm or more in consideration of process conditions.

Meanwhile, the Na ⁺ residual content in the polyarylene sulfide in the present invention can be measured by performing a cation analysis using an inductively coupled plasma spectrophotometer (ICP-OES) for each of the dried polyarylene sulfides. have.

In addition, the polyarylene sulfide includes a carboxyl group (-COOH) introduced at the terminal by acid washing. Accordingly, it can contribute to manufacturing a compound product having excellent physical properties without lowering the crystallinity, and when injection molding using the compounding composition to which the polyarylene sulfide is applied, the mechanical strength of the manufactured injection molded article is improved, and the color change Can be minimized. Specifically, the polyarylene sulfide prepared by the manufacturing method according to an embodiment of the present invention has a peak ratio of a carboxyl group (-COOH) based on a 1900 cm ^-1 peak of 0.09 or more, or 0.092 or more, or 0.095 or more. , Or 0.097 or more, which is 4 or more times higher than the carboxyl group peak ratio in the polyarylene sulfide prepared without acid washing.

In the present invention, the peak ratio of the carboxyl group (-COOH peak ratio) of the polyarylene sulfide is observed using the FTS-7000 (Varian), an FT-IR device, and the -COOH peak size of the polyarylene sulfide is observed, It can be calculated from the result. Specifically, 1705 cm ^-1 peak (or 1712 cm ^-1 ) was used to observe the -COOH peak size of polyarylene sulfide, and 1900 cm ^-1 peak was used to correct the deviation between measurements. Calculate the ratio.

Due to the above-described physical properties, polyarylene sulfide can exhibit excellent processability and improved kneading properties with glass fibers used in the compounding composition. As a result, it may be useful in the manufacture of a molded article for metal replacement in automobiles, electrical and electronic products, or mechanical parts, particularly in the manufacture of reflectors and base plates for automobile lamps that require excellent mechanical properties.

Hereinafter, the action and effect of the invention will be described in more detail through specific examples of the invention. However, this is presented as an example of the invention, and the scope of the invention is not limited to any meaning.

Example 1

Sodium sulfide (Na ₂ S) was prepared by mixing 1.00 equivalent of sodium hydrogen sulfide (NaSH) and 1.05 equivalent of sodium hydroxide (NaOH) in a 30 L reactor. At this time, 0.44 equivalents of sodium acetate (NaOAc) powder, 1.95 equivalents of N-methyl-2-pyrrolidone (NMP) and 4.72 equivalents of distilled water were added to the reactor.

The reactor was heated to 200° C. for 110 minutes while stirring at 150 rpm, followed by dehydration after completion of the reaction to obtain a residual mixture as a sulfur source.

After completion of dehydration, the temperature was lowered to less than 170° C., and 1.04 equivalents of para-dichlorobenzene (p-DCB) and 1.35 equivalents of NMP were added to the reactor. At this time, the input amount of p-DCB corresponds to 1.04 molar ratio with respect to 1 mol of hydrosulfide of the alkali metal, and after the addition of p-DCB and NMP, the molar ratio of H ₂ O/S in the resulting mixture is 1.73, The molar ratio of NMP/S was 3.24.

The mixture after the addition of the p-DCB solution was heated to 230° C. and reacted for 3 hours, and the temperature was raised to 260° C. and further reacted for 1 hour.

The resulting polyphenylene sulfide-containing slurry was washed according to the process chart shown in FIG. 1 below. Specifically, the polyphenylene sulfide (PPS)-containing slurry was washed at 150° C. for 30 minutes using NMP (5 times the total volume of the polyphenylene sulfide-containing slurry), followed by filtration, and then at 90° C. for 30 minutes. Washed with water. Thereafter, a 0.4% by weight aqueous acetic acid solution (Aq.AcOH) was washed at 90° C. for 30 minutes, filtered, and washed twice at 90° C. with water for 30 minutes. The washed PPS was recovered by drying in a vacuum oven at 150° C. for 8 hours.

Example 2

In Example 1, polyphenylene sulfide was prepared in the same manner as in Example 1, except that the conditions for preparing the sulfur source and the content condition of the raw material during the polymerization reaction of polyphenylene sulfide were changed.

Sodium sulfide (Na ₂ S) was prepared by mixing 1.00 equivalent of sodium hydrogen sulfide (NaSH) and 1.05 equivalent of sodium hydroxide (NaOH) in a 30 L reactor. At this time, 0.44 equivalents of sodium acetate (NaOAc) powder, 1.80 equivalents of N-methyl-2-pyrrolidone (NMP) and 4.72 equivalents of distilled water were added to the reactor.

The reactor was heated to 200° C. for 100 minutes while stirring at 150 rpm, and after completion of the reaction, dehydration was performed to obtain a residual mixture as a sulfur source.

After completion of dehydration, the temperature was lowered to less than 170° C., and 1.04 equivalents of para-dichlorobenzene (p-DCB) and 1.65 equivalents of NMP were added to the reactor. At this time, the input amount of p-DCB corresponds to 1.04 molar ratio with respect to 1 mol of hydrosulfide of the alkali metal, and after the addition of p-DCB and NMP, the molar ratio of H ₂ O/S in the resulting mixture is 1.95, The molar ratio of NMP/S was 3.38.

The mixture after the addition of the p-DCB solution was heated to 230° C. and reacted for 2 hours, and the temperature was raised to 255° C. and further reacted for 2 hours.

The resulting polyphenylene sulfide-containing slurry was washed according to the process chart shown in FIG. 1. Specifically, the polyphenylene sulfide-containing slurry was washed at 150° C. for 30 minutes using NMP (5 times the total volume of the polyphenylene sulfide-containing slurry), followed by filtration, and then washed with water at 90° C. for 30 minutes. . Thereafter, washing was performed at 90° C. for 30 minutes with a 0.4% by weight aqueous acetic acid solution, followed by filtration, followed by washing with water at 90° C. for 30 minutes twice. The washed PPS was recovered by drying in a vacuum oven at 150° C. for 8 hours.

Comparative Example 1

After the preparation of polyphenylene sulfide, a washing process was performed according to the process chart shown in FIG. 2.

Specifically, sodium hydrogen sulfide (Na ₂ S) was prepared by mixing 1.00 equivalent of sodium hydrogen sulfide (NaSH) and 1.05 equivalent of sodium hydroxide (NaOH) in a 30 L reactor. At this time, 0.44 equivalents of sodium acetate (NaOAc) powder, 1.65 equivalents of N-methyl-2-pyrrolidone (NMP) and 4.72 equivalents of distilled water were added to the reactor.

The reactor was heated to 200° C. for 110 minutes while stirring at 150 rpm, followed by dehydration after completion of the reaction to obtain a residual mixture as a sulfur source.

After completion of dehydration, the temperature was lowered to less than 170° C., and 1.04 equivalents of para-dichlorobenzene (p-DCB) and 1.65 equivalents of NMP were added to the reactor. At this time, the input amount of p-DCB corresponds to 1.04 molar ratio with respect to 1 mol of hydrosulfide of the alkali metal, and after the addition of p-DCB and NMP, the molar ratio of H ₂ O/S in the resulting mixture is 1.91, The molar ratio of NMP/S was 3.25.

The mixture after the addition of the p-DCB solution was heated to 230° C. and reacted for 3 hours, and the temperature was raised to 260° C. and further reacted for 1 hour.

The resulting polyphenylene sulfide-containing slurry was washed according to the process diagram shown in FIG. 2. Specifically, the polyphenylene sulfide-containing slurry was washed at 150° C. for 30 minutes using NMP (5 times the total volume of the polyphenylene sulfide-containing slurry), and then filtered, and a 0.4 wt% acetic acid aqueous solution was used at 90° C. for 30 minutes. After washing for a minute, it was filtered. The process of washing with water at 90° C. for 30 minutes was performed three times. The washed PPS was recovered by drying in a vacuum oven at 150° C. for 8 hours.

Comparative Example 2

In Comparative Example 1, polyphenylene sulfide was prepared in the same manner as in Comparative Example 1, except that the conditions for preparing the sulfur source and the content condition of the raw material during the polymerization reaction of polyphenylene sulfide were changed.

Sodium sulfide (Na ₂ S) was prepared by mixing 1.00 equivalent of sodium hydrogen sulfide (NaSH) and 1.05 equivalent of sodium hydroxide (NaOH) in a 30 L reactor. At this time, 0.44 equivalents of sodium acetate (NaOAc) powder, 1.95 equivalents of N-methyl-2-pyrrolidone (NMP) and 4.72 equivalents of distilled water were added to the reactor.

The reactor was heated to 195° C. for 110 minutes while stirring at 150 rpm, and after completion of the reaction, dehydration was performed to obtain a residual mixture as a sulfur source.

After completion of dehydration, the temperature was lowered to less than 170° C., and 1.04 equivalents of para-dichlorobenzene (p-DCB) and 1.35 equivalents of NMP were added to the reactor. At this time, the input amount of p-DCB corresponds to 1.04 molar ratio with respect to 1 mol of hydrosulfide of the alkali metal, and after the addition of p-DCB and NMP, the molar ratio of H ₂ O/S in the resulting mixture is 1.89, The molar ratio of NMP/S was 3.22.

The mixture after the addition of the p-DCB solution was heated to 230° C. and reacted for 3 hours, and the temperature was raised to 260° C. and further reacted for 1 hour.

The resulting polyphenylene sulfide-containing slurry was washed at 150° C. for 30 minutes using NMP (5 times the total volume of the polyphenylene sulfide-containing slurry) as shown in FIG. 2 and then filtered, and 0.4 wt% acetic acid After washing with an aqueous solution at 90° C. for 30 minutes, it was filtered. The process of washing with water at 90° C. for 30 minutes was performed three times. The washed PPS was recovered by drying in a vacuum oven at 150° C. for 8 hours.

Comparative Example 3

Polyphenylene sulfide was prepared in the same manner as in Example 1, except that the conditions for preparing the sulfur source in Example 1 and the concentration of the acid were changed during acid washing.

Sodium sulfide (Na ₂ S) was prepared by mixing 1.00 equivalent of sodium hydrogen sulfide (NaSH) and 1.05 equivalent of sodium hydroxide (NaOH) in a 30 L reactor. At this time, 0.44 equivalents of sodium acetate (NaOAc) powder, 2.25 equivalents of N-methyl-2-pyrrolidone (NMP) and 4.72 equivalents of distilled water were added to the reactor.

The reactor was heated to 200° C. for 110 minutes while stirring at 150 rpm, followed by dehydration after completion of the reaction to obtain a residual mixture as a sulfur source.

After completion of dehydration, the temperature was lowered to less than 170° C., and 1.04 equivalents of para-dichlorobenzene (p-DCB) and 1.35 equivalents of NMP were added to the reactor. At this time, the input amount of p-DCB corresponds to 1.04 molar ratio with respect to 1 mol of hydrosulfide of the alkali metal, and after the addition of p-DCB and NMP, the molar ratio of H ₂ O/S in the resulting mixture is 1.84, The molar ratio of NMP/S was 3.45.

The mixture after the addition of the p-DCB solution was heated to 230° C. and reacted for 3 hours, and the temperature was raised to 260° C. and further reacted for 1 hour.

The resulting polyphenylene sulfide-containing slurry was washed at 150° C. for 30 minutes using NMP (5 times the total volume of the polyphenylene sulfide-containing slurry), followed by filtration, and then washed with water at 90° C. for 30 minutes. . Thereafter, washing was performed at 90° C. for 30 minutes with 0.1% by weight aqueous acetic acid solution, followed by filtration, followed by washing with water at 90° C. for 30 minutes twice. The washed PPS was recovered by drying in a vacuum oven at 150° C. for 8 hours.

Comparative Example 4

Sodium sulfide (Na ₂ S) was prepared by mixing 1.00 equivalents of sodium hydrogen sulfide (NaSH) and 1.05 equivalents of sodium hydroxide (NaOH) in a 30L reactor. At this time, 0.44 equivalents of sodium acetate (NaOAc) powder, 1.65 equivalents of N-methyl-2-pyrrolidone (NMP) and 4.72 equivalents of distilled water were added to the reactor.

The reactor was heated to 195° C. for 100 minutes while stirring at 150 rpm, followed by dehydration after completion of the reaction to obtain a residual mixture as a source of sulfur.

After completion of dehydration, the temperature was lowered to less than 170° C., and 1.04 equivalents of para-dichlorobenzene (p-DCB) and 1.65 equivalents of NMP were added to the reactor. At this time, the input amount of p-DCB corresponds to 1.04 molar ratio with respect to 1 mol of hydrosulfide of the alkali metal, and after the addition of p-DCB and NMP, the molar ratio of H ₂ O/S in the resulting mixture is 2.02, The molar ratio of NMP/S was 3.28.

The mixture after the addition of the p-DCB solution was heated to 230° C. and reacted for 3 hours, and the temperature was raised to 255° C. and further reacted for 1 hour.

The resulting polyphenylene sulfide-containing slurry was washed with water (5 times the total volume of the polyphenylene sulfide-containing slurry) for 30 minutes and then filtered, followed by washing with acetone at 50° C. for 60 minutes. I did. Thereafter, a 0.4 wt% aqueous acetic acid solution was washed at 90° C. for 30 minutes, filtered, and washed twice with water at 90° C. for 30 minutes. The washed PPS was recovered by drying in a vacuum oven at 150° C. for 8 hours.

Comparative Example 5

In Example 1, except that the conditions for preparing the sulfur product, the content conditions of the raw material in the polymerization reaction of polyphenylene sulfide, and the primary washing process for the slurry containing polyphenylene sulfide were performed at 50°C, Polyphenylene sulfide was prepared by performing the same method as in Example 1.

Sodium sulfide (Na ₂ S) was prepared by mixing 1.00 equivalent of sodium hydrogen sulfide (NaSH) and 1.05 equivalent of sodium hydroxide (NaOH) in a 30 L reactor. At this time, 0.44 equivalents of sodium acetate (NaOAc) powder, 1.65 equivalents of N-methyl-2-pyrrolidone (NMP) and 4.72 equivalents of distilled water were added to the reactor.

The reactor was heated to 200° C. for 80 minutes while stirring at 150 rpm, followed by dehydration after completion of the reaction to obtain a residual mixture as a sulfur source.

After completion of dehydration, the temperature was lowered to less than 170° C., and 1.04 equivalents of para-dichlorobenzene (p-DCB) and 1.65 equivalents of NMP were added to the reactor. At this time, the input amount of p-DCB corresponds to 1.04 molar ratio with respect to 1 mol of hydrosulfide of the alkali metal, and after the addition of p-DCB and NMP, the molar ratio of H ₂ O/S in the resulting mixture is 1.89, The molar ratio of NMP/S was 3.24.

The mixture after the addition of the p-DCB solution was heated to 230° C. and reacted for 2 hours, and the temperature was raised to 255° C. and further reacted for 2 hours.

The resulting polyphenylene sulfide-containing slurry was washed at 50° C. for 30 minutes using NMP (5 times the total volume of the polyphenylene sulfide-containing slurry) and then filtered, followed by water at 90° C. for 30 minutes. Washed. Thereafter, washing was performed at 90° C. for 30 minutes with a 0.4% by weight aqueous acetic acid solution, followed by filtration, followed by washing with water at 90° C. for 30 minutes twice. The washed PPS was recovered by drying in a vacuum oven at 150° C. for 8 hours.

Comparative Example 6

Polyphenylene sulfide was prepared in the same manner as in Example 1, except that the washing process for the polyphenylene sulfide-containing slurry was changed as follows.

Specifically, the polyphenylene sulfide (PPS)-containing slurry obtained in Example 1 was mixed with water and NMP (water: NMP mixing volume ratio = 1:1) (5 times the total volume of the polyphenylene sulfide-containing slurry) Volume) was washed at 150° C. for 30 minutes and then filtered, followed by washing with water at 90° C. for 30 minutes and filtered. Subsequently, the mixture was washed with NMP for 10 minutes at 100° C. and filtered, and then washed with 0.4 wt% acetic acid aqueous solution (Aq.AcOH) at 120° C. for 30 minutes and filtered. Then, it was washed with water at 100° C. for 10 minutes. The washed PPS was recovered by drying in a vacuum oven at 150° C. for 8 hours.

Comparative Example 7

Polyphenylene sulfide was prepared in the same manner as in Example 1, except that the washing process for the slurry containing polyphenylene sulfide in Example 1 was changed as follows.

Specifically, the polyphenylene sulfide (PPS)-containing slurry obtained in Example 1 was placed in NMP heated to 100° C., stirred for 30 minutes, and filtered. Subsequently, washing and filtration were repeated 4 times using 90° C. water. The resulting washed product was added to an aqueous acetic acid solution of pH 6 heated to 90° C., stirred for 30 minutes, filtered, and dried in a vacuum oven at 150° C. for 5 hours to recover PPS.

Comparative Example 8

Polyphenylene sulfide was prepared in the same manner as in Example 1, except that the washing process for the polyphenylene sulfide-containing slurry was changed as follows.

Specifically, the polyphenylene sulfide (PPS)-containing slurry in Example 1 was washed at 150° C. for 30 minutes using NMP (5 times the total volume of the polyphenylene sulfide-containing slurry), and then filtered. It was washed with water at 90° C. for 30 minutes. Thereafter, a 0.4 wt% aqueous acetic acid solution (Aq.AcOH) was washed at 90° C. for 30 minutes, filtered, and washed twice at 60° C. with water for 30 minutes. The washed PPS was recovered by drying in a vacuum oven at 150° C. for 8 hours.

Comparative Example 9

Sodium sulfide (Na ₂ S) was prepared by mixing 1.00 equivalent of sodium hydrogen sulfide (NaSH) and 1.05 equivalent of sodium hydroxide (NaOH) in a 30 L reactor. At this time, 0.44 equivalents of sodium acetate (NaOAc) powder, 1.95 equivalents of N-methyl-2-pyrrolidone (NMP) and 4.72 equivalents of distilled water were added to the reactor.

The reactor was heated to 200° C. for 90 minutes while stirring at 150 rpm, and after completion of the reaction, dehydration was performed to obtain a residual mixture as a sulfur source.

After completion of dehydration, the temperature was lowered to less than 170° C., and 1.00 equivalent of para-dichlorobenzene (p-DCB) and 1.35 equivalent of NMP were added to the reactor. At this time, the input amount of p-DCB corresponds to 1.00 molar ratio with respect to 1 mol of hydrosulfide of the alkali metal, and after the addition of p-DCB and NMP, the molar ratio of H ₂ O/S in the resulting mixture is 1.76, The molar ratio of NMP/S was 3.25.

The mixture after the addition of the p-DCB solution was heated to 230° C. and reacted for 2 hours, and the temperature was raised to 255° C. and further reacted for 2 hours.

The resulting polyphenylene sulfide-containing slurry was washed according to the process chart shown in FIG. 1 below. Specifically, the polyphenylene sulfide (PPS)-containing slurry was washed at 150° C. for 30 minutes using NMP (5 times the total volume of the polyphenylene sulfide-containing slurry), followed by filtration, and then at 90° C. for 30 minutes. Washed with water. Thereafter, a 0.4% by weight aqueous acetic acid solution (Aq.AcOH) was washed at 90° C. for 30 minutes, filtered, and washed twice at 90° C. with water for 10 minutes. The washed PPS was recovered by drying in a vacuum oven at 150° C. for 8 hours.

As a result, the yield was greatly reduced to 62.3%, and the MFR value of PAS was 432.4 g/10min, measured at 315°C, 4 min, and 5kg load using MI-4 (Gottfert) according to ASTM-D1238-70.

Comparative Example 10

Sodium sulfide (Na ₂ S) was prepared by mixing 1.00 equivalent of sodium hydrogen sulfide (NaSH) and 1.05 equivalent of sodium hydroxide (NaOH) in a 30 L reactor. At this time, 0.44 equivalents of sodium acetate (NaOAc) powder, 1.95 equivalents of N-methyl-2-pyrrolidone (NMP) and 4.72 equivalents of distilled water were added to the reactor.

The reactor was heated to 195° C. for 60 minutes while stirring at 150 rpm, and after completion of the reaction, dehydration was performed to obtain a residual mixture as a sulfur source.

After completion of dehydration, the temperature was lowered to less than 170° C., and 1.08 equivalents of para-dichlorobenzene (p-DCB) and 1.35 equivalents of NMP were added to the reactor. At this time, the input amount of p-DCB corresponds to 1.08 molar ratio with respect to 1 mol of hydrosulfide of the alkali metal, and after the addition of p-DCB and NMP, the molar ratio of H ₂ O/S in the resulting mixture is 1.90, The molar ratio of NMP/S was 3.24.

The mixture after the addition of the p-DCB solution was heated to 230° C. and reacted for 2 hours, and the temperature was raised to 255° C. and further reacted for 2 hours.

The resulting polyphenylene sulfide-containing slurry was washed according to the process chart shown in FIG. 1 below. Specifically, the polyphenylene sulfide (PPS)-containing slurry was washed at 150° C. for 30 minutes using NMP (5 times the total volume of the polyphenylene sulfide-containing slurry), followed by filtration, and then at 90° C. for 30 minutes. Washed with water. Thereafter, a 0.4% by weight aqueous acetic acid solution (Aq.AcOH) was washed at 90° C. for 30 minutes, filtered, and washed twice at 90° C. with water for 10 minutes. The washed PPS was recovered by drying in a vacuum oven at 150° C. for 8 hours.

As a result, the yield was as high as 90.8%, but the MFR value of PAS measured at 315°C, 4 minutes, and 5kg load conditions using MI-4 (Gottfert) according to ASTM-D1238-70 was very high as 2495.4 g/10min. .

Test Example 1

In order to confirm the correlation between the -COOH peak ratio and the Na ⁺ residual content, and the correlation between the Na ⁺ residual content and the reactivity in polyphenylene sulfide, the concentration of the acid aqueous solution during the pickling in Example 1 (0 ~ 0.4wt%), the washing solvent (NMP or acetone), or the washing sequence, and the like, and after preparing polyphenylene sulfide, the -COOH peak ratio and Na ⁺ residual content of the prepared polyphenylene sulfide were prepared by the following method. , And the reactivity were measured respectively. The results are shown in FIGS. 3 and 4, respectively.

(1) COOH peak ratio

The COOH peak size of the PPS sample prepared using the FT-IR equipment FTS-7000 (Varian) was observed, and the COOH peak ratio was calculated from the result.

Specifically, 1705 cm ^-1 peak (or 1712 cm ^-1 ) was used to observe the COOH peak size of the sample, and the peak ratio was calculated based on 1900 cm ^-1 peak to correct the deviation between measurements. .

(2) Na ⁺ residual content

For each PPS sample that had been dried during PPS production, cation analysis was performed using an ICP-OES equipment Optima 8300DV (Perkin Elmer), and Na ⁺ residual content was confirmed.

(3) Reactivity with silane coupling agent

The reactivity of PPS to the silane-based coupling agent was measured.

Specifically, 5 g of each of the PPS prepared in Examples or Comparative Examples, 0.025 g of a silane coupling agent (Silquest A-187™), and 10 ml of dichloromethane were placed in a vial, sufficiently stirred, and then naturally dried for 24 hours. For the resulting reactant of PPS and the coupling agent (hereinafter simply referred to as PPS_CA reactant), MFR at 315°C, 4 minutes, and 5kg load conditions using MI-4 (Gottfert) according to ASTM-D1238-70. It was measured, and the reactivity was calculated according to Equation 1 below. When measuring the MFR, the inner diameter of the standard die was 2.1 mm and the length was 8 mm.

[Equation 1]

Reactivity = MFR _PPS / MFR _{PPS_CA reactant}

In Equation 1, MFR _PPS is the MFR of PPS itself, and the MFR _{PPS_CA reactant} refers to the MFR of PPS and the coupling agent reactant.

3 is a graph showing the relationship between Na ⁺ residual content (Na Contents, ppm) and carboxy group peak ratio (-COOH peak ratio) in polyphenylene sulfide, and FIG. 4 is a graph showing Na ⁺ residual content (Na Contents) in polyphenylene sulfide. , ppm) and the reactivity of polyphenylene sulfide (PPS reactivity).

As a result of the experiment, it was confirmed that the COOH peak ratio and reactivity tended to decrease as the Na ⁺ residual content in the polyphenylene sulfide increased. In addition, it can be seen that when the Na ⁺ residual content is 200 ppm or less, the reactivity is 1.7 or more, and when the Na ⁺ residual content is 150 ppm or less, the high reactivity is 2.0 or more. From this, it can be seen that the reactivity can be increased by reducing the Na ⁺ residual content in polyphenylene sulfide.

Test Example 2

The production yield and physical properties of polyphenylene sulfide according to the Examples and Comparative Examples were measured and evaluated in the following manner.

(1) yield

The production yield of polyphenylene sulfide in Examples and Comparative Examples is based on the weight of the polymer (theoretical amount) when it is assumed that all of the effective sulfur sources present in the reactor have been converted into a polymer after the dehydration process. The ratio (weight%) of the recovered polymer weight was calculated.

(2) melt flow rate (MFR)

For the PPS prepared in Examples and Comparative Examples, MFR was measured at 315° C., 4 minutes, and 5kg load using MI-4 (Gottfert) according to ASTM-D1238-70. At this time, the inner diameter of the standard die was 2.1 mm and the length was 8 mm.

(3) COOH peak ratio

Using the FT-IR equipment FTS-7000 (Varian) was used to observe the COOH peak size of the PPS samples prepared in the Examples and Comparative Examples, and the COOH peak ratio was calculated from the results.

Specifically, 1705 cm ^-1 peak (or 1712 cm ^-1 ) was used to observe the COOH peak size of the sample, and the peak ratio was calculated based on 1900 cm ^-1 peak to correct the deviation between measurements. .

(4) Na ⁺ residual content

When preparing PPS according to the above Examples and Comparative Examples, for each PPS sample after drying, a cation analysis was performed using an ICP-OES equipment Optima 8300DV (Perkin Elmer), and Na ⁺ residual content was confirmed.

(5) Reactivity with silane coupling agent

The reactivity of the PPS prepared in Examples and Comparative Examples with respect to the silane-based coupling agent was measured.

Specifically, 5 g of each of the PPS prepared in Examples or Comparative Examples, 0.025 g of a silane coupling agent (Silquest A-187™), and 10 ml of dichloromethane were placed in a vial, sufficiently stirred, and then naturally dried for 24 hours. For the resulting reaction product of PPS and the coupling agent (hereinafter simply referred to as PPS_CA reaction product), MFR was measured in the same manner as above, and the reactivity was calculated according to Equation 1 below.

[Equation 1]

Reactivity = MFR _PPS / MFR _{PPS_CA reactant}

In Equation 1, MFR _PPS is the MFR of PPS itself, and the MFR _{PPS_CA reactant} refers to the MFR of PPS and the coupling agent reactant.

As described above, the reactivity of PPS can be evaluated from the ratio of the MFR of the reactant of PPS and the coupling agent to the MFR of PPS, and the higher this ratio, the higher the reactivity of PPS to the coupling agent.

The experimental results are shown in Table 1 below.

yield(%) -COOH Peak ratio Na ⁺ residual content (ppm) MFR (g/10min)
(@315℃, 4min) Reactive PPS PPS_CA reactant Example 1 85.2 0.097 65 511.2 244.6 2.09 Example 2 86.3 0.095 95 476.8 213.8 2.23 Comparative Example 1 84.7 0.012 400 366.6 230.6 1.59 Comparative Example 2 85.6 0.007 545 400.5 247.2 1.62 Comparative Example 3 88.4 0.020 500 251.6 156.3 1.61 Comparative Example 4 84.9 0.001 810 806.6 650.5 1.24 Comparative Example 5 87.1 Not checked 1205 1655.2 1504.7 1.10

The polyphenylene sulfide of Examples 1 and 2 prepared through the polymerization and washing process of polyphenylene sulfide in the present invention was 200 to 1000 g/10min, specifically 450 to 550 g/10min compared to the comparative example. It exhibited a significantly reduced Na ⁺ residual content of 100 ppm or less with an MFR of, and exhibited a high reactivity of 2 or more with a ratio of -COOH peak of 0.095 or more (based on 1900 cm ^-1 peak).

On the other hand, although the polymerization process of polyphenylene sulfide in the present invention is satisfied, as shown in FIG. 2, the polyphenylene of Comparative Examples 1 and 2 in which the washing process was performed in the order of NMP washing -> acid washing -> water washing. In the case of sulfide, compared with Examples 1 and 2, the Na ⁺ residual content was greatly increased to 400 ppm or more, the ratio of the -COOH peak was significantly reduced to 0.02 or less, and the reactivity was also significantly reduced to 1.65 or less.

In addition, in the case of Comparative Example 4 in which the washing process was performed in the order of water washing -> acetone washing -> acid washing -> water washing, due to the difference in washing order and washing solvent, the Na ⁺ residual content rapidly increased to 800 ppm. And, the ratio of the -COOH peak was greatly reduced to 0.01, and the reactivity of the silane-based coupling agent was also significantly reduced to 1.24. Ketone-based solvents such as acetone are usually used as washing solvents in the washing process for separation and purification of polyarylene sulfide, but the use of the amide-based compound used in the polymerization reaction as an organic solvent for washing is not contained in the slurry. It can be seen that since the raw material removal effect is excellent, it can be more advantageous to realize the effect according to the present invention, particularly the effect of reducing the Na ⁺ residual content and increasing the reactivity of the silane-based coupling agent.

In addition, even if the washing process according to the present invention is performed, in the case of Comparative Example 3, which does not satisfy the acid concentration condition during acid washing, the Na ⁺ residual content is increased to 500 ppm, the ratio of the -COOH peak is 0.02, and the silane-based couple The reactivity with the ring agent was greatly reduced to 1.61. From these results, it can be seen that in order to realize the effect according to the present invention, concentration control during pickling is necessary in addition to the washing sequence.

In addition, from the results of Comparative Example 5, even if the washing process according to the present invention is performed, when the temperature conditions are not satisfied during the first washing process using an organic solvent, the first washing with an organic solvent is not sufficiently performed. The MFR of the PPS increased significantly to more than 1600 g/10min, and the Na ⁺ residual content in the PPS rapidly increased to more than 1000ppm, the -COOH peak was not confirmed, and the reactivity with the silane-based coupling agent was greatly increased to 1.10. Fell down. From these results, it can be confirmed that the temperature conditions during the first washing influence the implementation of the effects of the present invention.

In addition, although not included in the above experimental examples, when the first washing process with an organic solvent during the washing process is performed at a high temperature exceeding 180°C, the pressure in the reaction system increases, so that the produced polyarylene sulfide is added to the amide-based compound. It has dissolved.

Test Example 3

In order to evaluate the effect of the amount of residual acid in PPS on the reactivity, the amount of residual acid and the reactivity with the silane-based coupling agent were respectively evaluated for the PPS prepared in Examples 1 and 2 and Comparative Examples 6 to 8 above. I did.

To determine the amount of residual acid in PPS, the PPS prepared in Examples and Comparative Examples were added to distilled water at room temperature, stirred for 3 days, and then filtered, PPS was separated, and the pH of the remaining distilled water was measured using a pH meter. It was evaluated by measuring.

In addition, the reactivity of PPS was performed in the same manner as in (5) evaluation of the reactivity with the silane-based coupling agent in Test Example 2. The results are shown in Table 2.

pH Reactive Example 1 6.0 2.09 Example 2 6.5 2.23 Comparative Example 6 4.5 1.40 Comparative Example 7 4.2 1.24 Comparative Example 8 5.5 1.74

In the manufacturing method according to the present invention, in the manufacture of PPS, acid treatment is performed to replace the terminal group Na+ of PPS, and then the acid is removed with water.After drying, residual acid in PPS is not removed in the washing and drying process. Means that. Accordingly, the closer the pH of the distilled water is to neutral, the better, and when the pH is less than 6 or more than 8, the reactivity is poor.

As a result of the experiment, in the case of Comparative Example 6 in which the washing process with an organic solvent was performed before pickling, the pH was 4.5 and the reactivity was 1.40.

In addition, in the case of Comparative Example 7 in which water washing was not performed after acid washing, the content of the residual acid was high, indicating a pH of 4.2, and as a result, the reactivity was also significantly lowered to 1.24.

In addition, when washing with water after acid washing, even in the case of Comparative Example 8 in which the water temperature was less than 70° C., the residual acid was not sufficiently removed due to the low water washing temperature, thus exhibiting low reactivity at pH 5.5 and 1.74 levels.

Claims (14)

Reacting an alkali metal hydrosulfide and an alkali metal hydroxide in a mixed solvent of water and an amide compound to prepare a sulfur source including an alkali metal sulfide and a mixed solvent of the water and the amide compound;
Preparing a mixture by adding a dihalogenated aromatic compound and an amide compound to the sulfur source, and performing a polymerization reaction to prepare a polyarylene sulfide-containing slurry; And
Including; washing the slurry containing the polyarylene sulfide,
The dihalogenated aromatic compound is added in a molar ratio of more than 1 and not more than 1.07 with respect to 1 mol of the alkali metal hydrosulfide,
The washing is, for the polyarylene sulfide-containing slurry, a first washing using an amide compound at a temperature of 80°C or higher and 180°C or lower, a second washing using water, and an acid containing acid at a concentration of 0.3% by weight or more. A method for producing polyarylene sulfide, which is performed in the order of a third washing using an aqueous solution and a fourth washing using water of 70° C. or higher.
The method of claim 1,
After the addition of the dihalogenated aromatic compound and the amide compound, the molar ratio of water to 1 mole of sulfur in the mixture is 1.5 or more and 3.5 or less, and the molar ratio of the amide compound to 1 mole of sulfur is 1 or more and 3.5 or less.
The method of claim 1,
The dihalogenated aromatic compound comprises para-dichlorobenzene.
The method of claim 1,
The amide-based compound includes N-methyl-2-pyrrolidone.
The method of claim 1,
When the alkali metal hydrosulfide and the alkali metal hydroxide are reacted, an organic acid salt of an alkali metal is further added.
The method of claim 1,
The first washing is performed using an amide compound in a volume ratio of 5 times or more and 7 times or less with respect to the total volume of the polyarylene sulfide-containing slurry.
The method of claim 1,
The first washing is 120 ℃ or more, and is performed at a temperature of 170 ℃ or less, the manufacturing method.
The method of claim 1,
The secondary washing is more than 70 ℃, and is carried out at a temperature of less than 100 ℃, the manufacturing method.
The method of claim 1,
The third washing is performed at a temperature of 50° C. or higher and 100° C. or lower, using an acid aqueous solution containing 0.4% by weight or more of acid and at a concentration of 0.7% by weight or less based on the total weight of the acid aqueous solution. Way.
The method of claim 1,
The third washing is performed using acetic acid.
The method of claim 1,
The fourth washing is at least 70 ℃, at a temperature of less than 100 ℃, carried out two or more times, the manufacturing method.
The method of claim 1,
The polyarylene sulfide has a melt flow index of 200 g/10min or more and 1000 g/10min or less, measured under the conditions of 315°C, 4 minutes, and 5kg according to ASTM-D1238-70, and is determined according to Equation 1 below. The manufacturing method, wherein the reactivity with the silane-based coupling agent is 2 or more:
[Equation 1]
Reactivity = MFR _PPS / MFR _{PPS_CA reactant}
(In Equation 1, MFR _PPS is the melt flow rate of the polyarylene sulfide itself, and MFR _{PPS_CA reactant} is the melt flow rate of the reactant obtained as a result of the reaction of the polyarylene sulfide and the silane-based coupling agent, The melt flow rate is a value measured under the conditions of 315°C, 4 minutes, and 5kg according to ASTM-D1238-70)
The method of claim 1,
The polyarylene sulfide has a residual content of sodium cation of 100 ppm or less, and a ratio of -COOH peak based on 1900 cm ^-1 peak of 0.095 or more.
The method of claim 1,
The polyarylene sulfide is immersed in distilled water at a temperature of 18 to 25° C. for 3 days and the pH of the distilled water measured is 6 or higher.

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