JPH11171997A - Production of polyarylene sulfide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polyarylene sulfide extremely- superior in mechanical strength such as a tensile strength, a flexural strength and an impact strength. SOLUTION: This method for producing a polyarylene sulfide having amino group at the terminal and a molar ratio of the terminal amino group to benzene ring regulated so as to be (0.001-0.1)/(0.9-0.999) comprises synthesizing a polyarylene sulfide oligomer, further carrying out a polymerization reaction of the obtained oligomer by adding an amination agent, and carrying out an acid treatment after finishing the polymerization reaction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing polyarylene sulfide. More specifically, the present invention relates to a method for producing a polyarylene sulfide including a polyarylene sulfide having an amino group at a terminal.

[0002]

2. Description of the Related Art Polyarylene sulfide (hereinafter referred to as PA)
Resins are sometimes known as engineering plastics having excellent mechanical strength, heat resistance, chemical resistance and the like. By the way, polyarylene sulfide includes linear type, branched type and cross-linked type.
Branched and crosslinked types have the advantage of being superior in melting properties and less burr during molding than linear types, but have the disadvantage of insufficient mechanical properties. On the other hand, although the linear type has some mechanical properties, the melting properties are insufficient, and it cannot be said that the mechanical properties are still sufficient compared to other engineering plastics such as nylon. Further improvement is desired.

In recent years, for the purpose of improving the performance of such polyarylene sulfide resins, for example, they have been combined with other resins (Japanese Patent Laid-Open No. 4-213357) or copolymerized (Japanese Patent Laid-Open No. 8-134352). Publication), denaturation of polyarylene sulfide (JP-A-5-17 / 1990)
No. 0908) have been proposed, but none of these techniques has yet yielded a polyarylene sulfide resin having sufficiently excellent mechanical properties such as tensile strength, bending strength and impact resistance. is there.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and provides a method for producing a polyarylene sulfide which is remarkably excellent in mechanical strength such as tensile strength, bending strength and impact resistance. The purpose is to do.

[0005]

Means for Solving the Problems As a result of diligent studies, the present inventors have conducted an acid treatment in the production process of polyarylene sulfide including polyarylene sulfide having an amino group at the terminal, thereby obtaining the above object. Can be achieved. The present invention has been made based on such findings.

That is, the present invention provides the following method for producing a polyarylene sulfide. (1) A polyarylene sulfide containing a polyarylene sulfide having an amino group at a terminal, wherein the molar ratio of the terminal amino group to a benzene ring is 0.001 to 0.1 / 0.9.
A polyarylene sulfide oligomer, wherein the polyarylene sulfide oligomer is synthesized, the polymerization reaction is further carried out by adding an aminating agent, and the acid treatment is carried out after completion of the polymerization. Method for producing sulfide.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. 1. A polyarylene sulfide containing a polyarylene sulfide having an amino group at a terminal, wherein the molar ratio of the terminal amino group to a benzene ring is 0.001 to 0.1 / 0.9 to 0.9.
0.99 polyarylene sulfide (1) polyarylene sulfide containing amino group-terminated polyarylene sulfide The “polyarylene sulfide containing amino group-terminated polyarylene sulfide” according to the present invention includes:
It may be composed of only polyarylene sulfide having an amino group at the terminal, or may be a mixture of polyarylene sulfide having an amino group at the terminal and polyarylene sulfide not having an amino group at the terminal.

The polyarylene sulfide is specifically a polymer containing at least 70 mol% of a repeating unit represented by the structural formula -Ar-S- (where Ar is an arylene group). The typical one is represented by the following structural formula (I)

[0009]

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(Wherein R ¹ is an alkyl group having 6 or less carbon atoms, an alkoxy group, a phenyl group, a carboxylic acid / metal salt,
A substituent selected from an amino group, a nitro group, a halogen atom such as fluorine, chlorine, and bromine, and m is an integer of 0 to 4. N is an average degree of polymerization and is in the range of 1.3 to 30), and is a polyphenylene sulfide having a repeating unit represented by at least 70 mol%.

Examples of the PAS include homopolymers and copolymers (hereinafter abbreviated as PPS) containing 70 mol% or more, more preferably 80 mol% or more of paraphenylene sulfide units as repeating units. Examples of the copolymerizable structural unit include a metaphenylene sulfide unit, an orthophenylene sulfide unit, a p, p′-diphenylene ketone sulfide unit, a p, p′-diphenylene sulfone sulfide unit, a p, p′-biphenylene sulfide unit, and p , P'-diphenylene ether sulfide unit, p, p'-diphenylene methylene sulfide unit, p, p'-diphenylene cumenyl sulfide unit, naphthyl sulfide unit and the like. PAS
Preferable examples include polyphenylene sulfide represented by the following structural formula (II) (hereinafter sometimes referred to as PPS).

[0012]

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The term "polyarylene sulfide having an amino group at the terminal" refers to the above-mentioned polyarylene sulfide in which both terminals or one terminal of the polymer chain is not -SH but an amino group such as -NH ₂ . (2) In the case where the polyarylene sulfide according to the present invention is a mixture of a polyarylene sulfide having an amino group at the terminal and a polyarylene sulfide having no amino group, the molar ratio between the terminal amino group and the benzene ring is as follows. , The molar ratio between the terminal amino group and all benzene rings. The term “all benzene rings” refers to the total number of benzene rings in polyarylene sulfide having an amino group at the terminal and polyarylene sulfide having no amino group at the terminal. When the molar ratio between the terminal amino group and the benzene ring is 0.001 to 0.1.
/0.9 to 0.999, preferably 0.005 to 0.05 / 0.9.
5 to 0.995. If the molar ratio between the terminal amino group and the benzene ring exceeds 0.1 / 0.9, the molecular weight may be low as polyarylene sulfide. 0.
If it is less than 001 / 0.999, the mechanical strength may be reduced. 2. The method for producing a polyarylene sulfide according to the present invention is a method for producing a polyarylene sulfide according to the present invention, in which a polyarylene sulfide oligomer is first synthesized, and then a polymerization reaction is further performed by adding an aminating agent. It is characterized by processing.

Hereinafter, the manufacturing method will be described in detail. (1) Synthesis of polyarylene sulfide oligomer A polyarylene sulfide oligomer can be produced by a known method of polycondensing a dihaloaromatic compound with a sulfur source in an organic polar solvent. Specifically, by introducing a liquid or gaseous sulfur compound into an aprotic solvent containing lithium hydroxide, lithium hydroxide and the sulfur compound are directly reacted, and the dihalogenated aromatic compound is contained in the reaction solution. A preferred method is to introduce a group compound and carry out polycondensation. The reaction between lithium hydroxide and a sulfur compound is Li / S = 2
Those performed under the above (molar ratio) conditions are preferred.

As the aprotic organic solvent used, generally, aprotic polar organic compounds (for example, amide compounds, lactam compounds, urea compounds, organic sulfur compounds, cyclic organic phosphorus compounds, etc.) are used as single solvents. Or as a mixed solvent. Among these aprotic polar organic compounds, amide compounds include, for example, N, N-dimethylformamide, N, N-diethylformamide, N, N
-Dimethylacetamide, N, N-diethylacetamide, N, N-dipropylacetamide, N, N-dimethylbenzoic acid amide, and the like, and examples of the lactam compound include caprolactam, N-methylcaprolactam, and N-ethylcaprolactam. , N-isopropylcaprolactam, N-isobutylcaprolactam, N-normalpropylcaprolactam, N-normalbutylcaprolactam, N-cyclohexylcaprolactam, etc.
-Alkylcaprolactams, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-isobutyl-2-pyrrolidone, N-normalpropyl-2-pyrrolidone, N
-Normal butyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, N-methyl-3-methyl 2-pyrrolidone, N-ethyl-3-methyl-2-pyrrolidone,
N-methyl-3 4,5-trimethyl-2-pyrrolidone, N-methyl-2-piperidone, N-ethyl-2-piperidone, N-isopropyl-2-piperidone, N-methyl-6-methyl-2-piperidone , N-methyl-3-
Ethyl-2-piperidone and the like can be mentioned.

The urea compounds include, for example, tetramethylurea, N, N'-dimethylethyleneurea, N,
N'-dimethylpropylene urea; and the organic sulfur compound includes, for example, dimethyl sulfoxide, diethyl sulfoxide, diphenyl sulfone, 1-
Methyl-1-oxosulfolane, 1-ethyl-1-oxosulfolane, 1-phenyl-1-oxosulfolane, etc. Examples of the cyclic organic phosphorus compound include 1-methyl-1-oxophospholane, -Normalpropyl-1-oxophosphorane, 1-phenyl-1-
Oxophosphorane and the like can be mentioned.

Each of these various aprotic polar organic compounds may be used alone or in combination of two or more.
Furthermore, it can be used by mixing with other solvent components that do not interfere with the object of the present invention. Among the above-mentioned various aprotic organic solvents, preferred are N-alkylcaprolactam and N-alkylpyrrolidone, and particularly preferred is N-methyl-2-pyrrolidone. (2) Synthesis of polyarylene sulfide To the reaction solution containing the polyarylene sulfide oligomer, an aminating agent and, if necessary, a branching agent, lithium hydroxide and water are added, and the temperature is raised to cause a reaction. Can be obtained.

The molar ratio between the terminal amino group and the benzene ring is
It can be controlled by the amount of the aminating agent. The aminating agent is not particularly limited, for example,
(Ii) a combination of an amino group and a thiol group, (ii) a combination of an amino group and a thiol group and an alkaline compound, and (iii) a compound having an amino group and a thiolate group (-SM; M is an alkali or alkaline earth metal). And (i)
To (iii) may be appropriately combined. Examples of (i) include para-aminothiophenol, ortho-aminothiophenol, aminoalkylmercaptan and the like, and para-aminothiophenol and ortho-aminothiophenol are preferred. As the alkaline compound of (ii), in principle, any compound capable of converting the thiol group of the compound of (i) to a thiolate group may be used, and specifically, an alkali metal or earth metal hydroxide or A carbonate may be mentioned, and a mixture of a hydroxide and a carbonate may be used. (Iii) as paraaminothiophenol,
Metal salts such as orthoaminothiophenol and aminoalkylmercaptan can be mentioned.

In the present invention, orthoaminothiophenol is preferably used. The branching agent used as necessary is not particularly limited. For example, a polyhalogen aromatic compound having three or more halogens per molecule such as 1,2,4-trichlorobenzene or 1,2,4-trichlorobenzene Polyfunctional compounds such as 4-trichloronitrobenzene are preferred.

Reaction Conditions The reaction between the PAS oligomer and the aminating agent in the aprotic organic solvent is not particularly limited, but the following conditions are preferred. (i) Reaction concentration and mixing ratio The reaction concentration of polyarylene sulfide is preferably 50 to 500 g per liter of aprotic organic solvent,
100-400 g is more preferred. If the amount is less than 50 g, the productivity may decrease. If the amount exceeds 500 g, the reaction rate may decrease and side reactions may occur.

The compounding ratio of the aminating agent is preferably from 0.1 to 10 mol%, more preferably from 0.5 to 5 mol%, based on 1 basic mol of polyarylene sulfide. If the amount is less than 0.1 mol%, the proportion of the terminal aminated PAS in the produced PAS becomes small, and the mechanical strength may be lowered.
On the other hand, if it exceeds 10 mol%, the molecular weight of the resulting PAS may be reduced. (Ii) Timing of addition of the aminating agent Although not particularly limited, a method of adding the aminating agent to the reaction solution containing the polyarylene sulfide oligomer from the beginning or a method of adding the aminating agent during the reaction is also used. (Iii) Reaction temperature The reaction temperature is preferably from 180 ° C to 300 ° C,
280 ° C. is more preferred. If the temperature is lower than 180 ° C., amination may not proceed sufficiently, and if it exceeds 300 ° C., the PAS may be deteriorated. (Iv) Reaction time The reaction time cannot be specified unconditionally, but is usually 30 minutes to 3 minutes.
0 hours is preferable, and 1 to 15 hours is more preferable. 3
If the reaction time is less than 0 minutes, the reaction may be insufficient.
Beyond 0 hours, side reactions occur and terminal aminated P
The molecular weight of AS may decrease.

Polymer recovery and post-treatment The recovery of the polyarylene sulfide obtained as described above is not particularly limited, and a usual method such as filtration may be used. Post-treatment of polymer For post-treatment of the recovered polyarylene sulfide, it is essential to include an acid wash for alkali neutralization, but before performing the acid wash, after filtering the polymer,
First, it is desirable to perform water washing for removing salts. Further, after the acid washing, it is desirable to carry out water washing for removing the remaining acidic solvent and salt.

The acid cleaning is preferably performed as follows. (i) The washing method is not particularly limited. For example, the polymer and the acid are preferably placed in the aprotic organic solvent described above, and it is preferable that the washing is carried out by means of shaking or the like so that the mixture is sufficiently mixed. Is more preferably heated. (ii) The type of acid used is not particularly limited as long as it does not have an action of decomposing polyarylene sulfide, but acetic acid or hydrochloric acid is preferably used from the viewpoint of ease of handling and post-treatment. (iii) The mixing ratio of the polymer, the aprotic organic solvent and the acid varies depending on the kind of the acid used or the conditions at the time of the polymerization reaction, but usually 50 to 500 g of the polymer per liter of the aprotic organic solvent, preferably Is 10
0 to 400 g. For the acid, the measured p when the aprotic organic solvent was diluted 10-fold with ion-exchanged water.
H is selected so that it is 1-5, preferably 2-4.

More specifically, for example, when acetic acid is used as the acid, 50 to 500 g of the polymer and 0.3 to 3000 g of the acetic acid, or 100 to 400 g of the polymer and 3 to 300 g of acetic acid per liter of the aprotic organic solvent are used. Is preferred. (iv) The washing temperature is 50 to 300 ° C., preferably 80 to 2 ° C.
80 ° C. If the temperature exceeds 300 ° C., the polymer may be decomposed, and if it is lower than 50 ° C., the cleaning effect may not be exhibited. (v) Although the washing time cannot be specified unconditionally, it is usually preferably 30 minutes to 30 hours, more preferably 1 to 15 hours.

After washing, it is preferable to perform hot air drying or vacuum drying at 100 ° C. or more for 5 hours or more. [Examples] Hereinafter, the present invention will be described more specifically with reference to examples. The evaluation was performed by the following method. (1) Solution viscosity (η _inh ) Using an Ubbelohde viscometer, a sample was held and dissolved in an α-chloronaphthalene solution having a concentration of 0.4 g / deciliter and a temperature of 235 ° C. for 30 minutes, and then measured at 206 ° C. . (2) Melt viscosity (η _m ) A sample of 20 g was pressed into a sheet and then pulverized into pellets, using a Capillograph measuring device manufactured by Toyo Seiki Co., Ltd., measuring temperature 300 ° C., L / D = 40/1.
Was measured under the following conditions. (3) Quantitative FT-IR of the amino group (BIO-LAD Co., FTS-165) by, NH stretching vibration (NH, 3370cm ^-1) and aromatic hydrogen stretching vibration (benzene -H, 3066cm ^-1 ) Was calculated based on the elemental analysis values. (4) Izod impact resistance (notched / notched) A sample for evaluation was prepared as follows.

The above polyphenylene sulfide granules 600
g, a coupling agent (manufactured by Dow Corning Toray Silicone Co., Ltd., trade name: SH6040) was evenly sprinkled with a disposable syringe, and was placed in a polypropylene bag and dry blended. Thereafter, 400 g of glass fiber (trade name: JAFT591 manufactured by Asahi Glass Co., Ltd.) was placed in the bag, and dry blending was performed slowly so that the glass fiber was not broken. This was pelletized with a 20 mmφ single screw extruder.

Using the pellets thus obtained, 3
A sample for evaluating Izod impact resistance was prepared using a 0t injection molding machine (mold temperature: 135 ° C., injection pressure: 49%). Using this sample, the measurement was performed in accordance with ASTM-D256. [Example 1] Stainless steel 1 with a stirrer equipped with stirring blades
In a 0 liter autoclave, 4.5 liters of N-methyl-2-pyrrolidone (NMP), 1323.0 g of paradichlorobenzene (PDCB) and lithium sulfide (Li)
Were charged ₂ S) _413.5g, under a nitrogen atmosphere, the temperature was raised to 200 ° C., reacted for 5 hours to synthesize polyarylene sulfide oligomer.

Next, the reaction solution was once returned to room temperature, and 22.6 g of orthoaminothiophenol, 4.3 g of lithium hydroxide and 48.6 g of pure water were added thereto.
The reaction was performed at 60 ° C. for 3 hours. After the reaction is completed, the internal temperature is
And the contents were removed and filtered. Then, it was washed three times with 10 liters of ion-exchanged water. Subsequently, the washed polymer, 5 liters of NMP and 20 ml of acetic acid were charged into a 10 liter autoclave, and acid-washed at 150 ° C. for 1 hour in a nitrogen atmosphere. After cooling, the polymer taken out was further washed four times with 10 liters of ion-exchanged water, and the polymer was separated by filtration.

The polymer thus obtained was dried under reduced pressure at 100 ° C. for 8 hours to obtain a white, granular polyphenylene sulfide polymer. Solution viscosity of this polymer (η
_inh ) is 0.22 deciliter / g, shear rate 200 cm
The melt viscosity at 50 g / sec (η ₂₀₀ ) was 95 Pa · s, and the molar ratio of amino groups to the total amount of benzene rings was 0.85%. The Izod impact resistance (notched / notched) is 10.8 / 71.5 (unit is kJ / m ² )
Met. [Example 2] The procedure of Example 1 was repeated, except that pure water 24.3 g was used instead of pure water 48.6 g. The solution viscosity (η _inh ) of the obtained polymer was 0.24 deciliter / g, and the melt viscosity (η ₂₀₀ ) was 110.
Pa.s and the molar ratio of amino groups to the total amount of benzene rings were 0.86%. Also, the Izod impact resistance (notched / notched) was 11.3 / 75.0 (unit: kJ / m ² ). Example 3 Example 1 was repeated except that in addition to adding 22.6 g of orthoaminothiophenol and 48.6 g of pure water, 11.3 g of orthoaminothiophenol and 56.7 g of pure water were used. The same was done. The solution viscosity (η _inh ) of the obtained polymer was 0.235 deciliter / g, the melt viscosity (η ₂₀₀ ) was 105 Pa · s, and the molar ratio of amino groups to the total benzene ring amount was 0.45%. The Izod impact resistance (notched / notched) is 11.0
/73.5 (unit: kJ / m ² ). Example 4 In Example 1, after the oligomer synthesis, 22.6 g of orthoaminothiophenol, 81.0 g of pure water, 4.3 g of lithium hydroxide and 8.2 g of 1,2,4-trichlorobenzene were added. The procedure was performed in the same manner as in Example 1 except that the reaction was performed at 260 ° C. for 3 hours under a nitrogen atmosphere. The solution viscosity (η _inh ) of the obtained polymer was 0.201 deciliter /
g, melt viscosity (η ₂₀₀ ) was 32 Pa · s, and the molar ratio of amino groups to the total benzene ring amount was 1.03%. The Izod impact resistance (with / without notch)
It was 9.7 / 63.5 (the unit was kJ / m ² ). [Comparative Example 1] The procedure of Example 1 was repeated, except that the acid cleaning was not performed. The solution viscosity (η _inh ) of the obtained polymer was 0.22 deciliter / g, the melt viscosity (η ₂₀₀ ) was 95 Pa · s, and the molar ratio of amino groups to the total benzene ring amount was 0.85%. The Izod impact resistance (notched / notched) is 7.2 / 5
0.0 (unit: kJ / m ² ). [Comparative Example 2] The procedure of Example 2 was repeated, except that the acid washing was not performed. The solution viscosity (η _inh ) of the obtained polymer was 0.24 deciliter / g, the melt viscosity (η ₂₀₀ ) was 110 Pa · s, and the molar ratio of amino groups to the total amount of benzene rings was 0.86%. The Izod impact resistance (notched / notched) is 7.8 / 5
5.0 (unit: kJ / m ² ). [Comparative Example 3] The procedure of Example 3 was repeated, except that the acid washing was not performed. The solution viscosity (η _inh ) of the obtained polymer was 0.235 deciliter / g, the melt viscosity (η ₂₀₀ ) was 105 Pa · s, and the molar ratio of amino groups to the total benzene ring amount was 0.45%. The Izod impact resistance (notched / notched) is 7.5 /
52.0 (all units were kJ / m ² ). Comparative Example 4 The procedure of Example 4 was repeated, except that the acid cleaning was not performed. The solution viscosity (η _inh ) of the obtained polymer was 0.201 deciliter / g, the melt viscosity (η ₂₀₀ ) was 33 Pa · s, and the molar ratio of amino groups to the total amount of benzene rings was 1.01%. Izod impact resistance (notched / notched) is 6.7 / 3
It was 9.0 (all units were kJ / m ² ).

[0030]

As described above, according to the present invention, it is possible to obtain a polyarylene sulfide which is excellent in mechanical strength such as tensile strength, bending strength and impact resistance.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Mikiya Hayashi 1-1, Anesaki Beach, Ichihara-shi, Chiba Prefecture (72) Minoru Chiga 1-1-1, Anesaki Beach, Ichihara-shi, Chiba Prefecture

Claims (1)

[Claims] 1. A polyarylene sulfide comprising an amino-terminated polyarylene sulfide,
The molar ratio of the terminal amino group to the benzene ring is 0.001 to
In the method for producing a polyarylene sulfide having a ratio of 0.1 / 0.9 to 0.999, a polyarylene sulfide oligomer is synthesized, a polymerization reaction is further performed by adding an aminating agent, and an acid treatment is performed after the polymerization is completed. A method for producing polyarylene sulfide, comprising: