JPS5949232A - Manufacture of polyphenylene sulfide - Google Patents

Abstract

PURPOSE:To obtain a polyphenylene sulfide with high bulk density, easy to handle, by polymerization, in the presence of a sulfur source and amide-based solvent, of an aromatic polyhalide immediately followed by gradually cooling the system to make the polymer separate out in the form of granules of specific size. CONSTITUTION:An aromatic polyhalide containing pref. >=70wt% of p-dihalobenzene is subjected to polymerization on stirring in an inert atmosphere pref. at 220-280 deg.C for 1-5hr, in the presence of a sulfur source (e.g., sodium sulfide) and amide-based solvent (e.g., N-methyl pyrrolidone). Following completion of the polymerization, the system is gradually cooled at a rate of 50 deg.C/min (pref. slower than 10 deg.C/min) to 240 deg.C or lower to make the resulting polymer separate out in the form of granules, thus obtaining the objective polyphenylene sulfide with a crystallite size of 60Angstrom or larger.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyphenylene sulfide having a shape convenient for handling such as washing and transportation.

Conventionally, polyphenylene sulfide was produced by reacting sodium sulfide and dichlorobenzene in N-methylpyrrolidone.
It is known that linear polymers can be prepared using alkali metal carboxylates and the like as auxiliaries.

However, the obtained polymer is in the form of a fine powder that forms bridges, and handling is such that it does not form bridges.6. A polymer with a large degree of bulk was not obtained.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for producing bolytho:I-nylene sulfide having a large bulk density, which is convenient for washing, filtration, transportation, etc.

This objective is achieved each time the polymer is precipitated into particles in the system immediately after 10 minutes.

Therefore, the method for producing polyphenylene sulfite according to the present invention involves combining an aromatic polyphenylene sulfide with a sulfur source and the presence of an amide solvent to produce ζ polyphenylene sulfide. from the polymerization temperature to a temperature of 240°C or higher.
In a special invention characterized in that the polymer is precipitated into particles by slow cooling at a rate slower than 1 minute, and the size of the microcrystals in the polymer is 60 Å or more, a polyphenylated resulfide is produced. The aromatic polyhalide used in the invention must contain at least 70% p-dihalobenzene, and if it is less than 30%, it is m-dihalobenzene or 0-dihalohene.

Trifunctional or higher-functional halogenated aromatic compounds, polyhalogen compounds containing heterogeneous bonds such as sulfones and ketones.

There is no problem even if it contains an aliphatic polyhalogen compound or the like.

If less than 70 mol % of p-dihalobenzene is used, the resulting polymer will have poor crystallinity, and even if the method of the present invention is applied, it will be difficult to obtain a particulate polymer.

As the sulfur source for sulfidation, monosulfides such as alkali sulfides and alkaline earth sulfides, combinations of alkali hydrosulfides and alkali metal bases, and combinations of hydrogen sulfide and alkali metal bases can be preferably used. When alkali sulfide is produced by a combination of alkali hydrosulfide or hydrogen sulfide and an alkali metal base and used for polymerization, the molar ratio of the alkali metal base to the alkali hydrosulfide or hydrogen sulfide at the time of adjustment is 64[alkali chloride]. The necessary information to generate! (1,0 molar ratio) ratio of 0.9
It is preferable to select the amount in the range of 2.0 times (base excess).

Specific sulfur sources include sodium chloride, sodium sulfide, sodium hydrogen sulfide and sodium hydroxide, and hydrogen sulfide and sodium hydroxide.

T as an auxiliary agent to increase the degree of polymerization? C00M
(R is C1-C21, Alko 1-Month) Manoko It-
j'reel, M represents an alkali metal), etc. can be added.

Examples of amide-based solvents that can be used for polymerization include N-methylpyrrolidone, N-ethylpyrrolidone, N,
Examples include N-dimethylimidazolidinone, 9'-methylphosphoramide, dimethylacetyl-amyl, etc.
Particularly preferred are solvents based on methyl birolinton.

Prior to polymerization, the sulfur source and Ami-1 solvent may be mixed in any order, and auxiliary agents and the like may be added at any time. If 1.5 liters or more of water is present in the system prior to polymerization relative to the sulfur source used, it is preferable to carry out dehydration. For dehydration, it is preferable to use distillation. At that time, distillation by adding an azeotropic reagent or the like may be carried out.
This can be done by heating at temperatures below .degree.

An aromatic polyhalide (and a copolymerization halide if copolymerization is carried out) is added to the dehydrated system and heated to 200 to 300' C1, preferably 220
~280°C for 1 to 15 hours, preferably 1 to 15 hours.
Polymerization is carried out under stirring for 5 hours. A method that changes the temperature increase schedule during polymerization can also be applied. It is also possible to add various reagents to the system immediately before or after the end of the polymerization in order to modify the polymer, especially at the ends.

Here, the end of polymerization refers to the point at which the system starts to be cooled after the residual aromatic polyhalide in the system becomes 10 mol% or less with respect to the initial charge amount, -
By this point, more than 95% of the generation of polymerization heat has been completed.

When the polymerized system is rapidly cooled at a cooling rate exceeding 50° C./min, a very bulky 1iill [powder-like polymer] is obtained. For example…alloy to water! - When the polymerization system is rapidly cooled from around 0℃, thermal analysis by differential thermal analysis (+) SC shows that a crystallization peak is observed when the temperature is raised. A polymer with a high ratio of crystalline parts and a low bulk density is obtained, and X-ray analysis shows that the size of microcrystals of this polymer has grown to only about 40 to 50 crystals.

There are 5 types of polymers available! It is IE. The polymerization temperature inside the system was maintained at 2 4 (when cooling from a temperature exceeding 1°C to a temperature below 50°C).
When slowly cooled at a rate slower than ℃/min, preferably slower than 10℃/min, the polymer crystallizes in the form of particles from within the system, and the microcrystals grow to a size of 60 Å or more, making them convenient to handle. A polymer with high density is obtained. The F limit up to 240℃ or below may be around room temperature, but it should be at least 200℃.
It is better to perform gradual cooling to about ℃. Any gradual temperature reduction is acceptable as long as the rate is slower than 50'c/min.

The bulk density of poly-7 obtained in this invention is 0.1, ~0
, 8 g/cc, and no crystallization peak is observed at elevated temperature even when measured by DSC. The polymer obtained by this invention is in the form of particles, but the shape can be more specifically determined depending on the composition within the system.

It is subdivided into beads, flakes, etc. However, in any case, the microcrystal size of 60 Å or more and 0.1 to 0.8
It has a bulk density in the range of g/cc.

Did you undergo slow cooling? The polymerized system is recovered by precipitating the polymer in water, but the temperature in the system immediately before it is introduced into water must be lower than the temperature in the system when crystallization is completed. The water in which the polymer is precipitated may be hard water or soft water, and may have a pH of 7 or more or less than 7. Oliva components can also be removed from the precipitated polymer by washing or extraction with water, an organic solvent, or the like.

This invention is particularly effective when polyphenylene sulfide with a high degree of polymerization is obtained using an auxiliary agent under the following conditions. That is, carboxylates having the structure RCOOM, such as lithium acetate, sulfurium acetate, sulfurium benzoate J1. Sodium propionate, Schiff 1
．． '+ -S L Lithium dosancarphonate, thoriumzotylate, lithium halide, such as lithium chloride, or lithium bromide are listed as the sulfur source and 5 to 2
This is the case where it is used in a range of 00 mol%. Polyphenylene sulfite with a high degree of polymerization is heated at 300°C.
Under a shear rate of 200 (I seconds), the viscosity of the melt is 100 to 50,000, preferably 500 to 20,000.

The slow cooling after polymerization is preferably carried out under stirring so that there are no residual parts in the system.

The polymer obtained by the method of the present invention can be further subjected to a crosslinking reaction in an oxidizing atmosphere such as air to increase its apparent melt viscosity.

The polymer of this invention can be used for injection molding, 1-transfer molding, extrusion molding, etc., and for producing various molded products, films, fibers, etc. At that time, there is no problem even if it is mixed with other materials or additives such as various stabilizers are added.

The crystallite size was determined by wide-angle X-ray diffraction reflection method (2,0
, 0) from the half width of the diffraction intensity of the plane.

For X-ray measurements, slit system 1) S S S =
1°.

The measurement conditions were R, S-'Q, 3 u+, and a scan speed of 1''/min.

In this invention, after polymerization, the system is slowly cooled at a speed below a certain value, the polymer is crystallized and precipitated into particles, and the polymer grains have a microcrystal size that has grown above a certain value. This makes it possible to obtain polyphenylene sulfide with a large bulk density that is convenient to handle without forming bridges, and is especially suitable for transportation in the popper or screw of an extruder or molding machine. It is something that has a shape.

Hereinafter, the present invention will be explained in more detail by describing Examples and Comparative Examples.

[Example 1 and Comparative Example 1] 57! In an autoclave, 12.5 mol of N-methyl pyrrolithon, 5 mol of sulfurized ``1~lium nonahydrate and 3
．． Add 0 mol of sodium benzoate and heat under a nitrogen stream until the internal temperature reaches 230℃! Then, when water was distilled off using a distillation tower, 40.3 mol of water was recovered and at the same time - part of the solvent was distilled off. After cooling the inside of the system to 180°C, 5.05 mol of p-dichlorohenzene and 0.5 mol of p-dichlorohenzene were added. 1°2.4 trichlorhenzene of Ol'Il-L was added and encapsulation was performed with nitrogen at 2 kg/cJ. Gradually rising? After 27t and polymerization at 260°C for 2 hours, It! 1 inside the system under J l'l'
The autoclave was slowly cooled to 50°C at a rate of 1'C/l), and then the autoclave was opened and the contents were poured into water. The viscosity is 3500 voids, the apparent bulk density is 0.
It showed 5 g/cc and the microcrystal size was 90 on X-ray. This polymer was easy to handle, such as washing and filtration, and exhibited good fluidity, forming bridges in the hopper when melted and ready for use in an extruder.

For comparison, after polymerization was carried out for a short period of time, the substances in the system were immediately put into water at 10°C at an initial pressure of 12 kg/kg for about 5 seconds through a withdrawal pipe installed at the bottom of the pot at 260°C.
The entire amount was extracted under a pressure of cJ. The obtained polymer was very bulky, and the polymer was repeatedly washed with hot water to obtain a pulp-like polymer. When this polymer was heated by Perkin-E1mer type DSC, it had a glass transition temperature at 87°C and a crystallization peak at 134°C. There were many polymers. This polymer has a bulk density of 0.03 g/cc.

It was found that the shape was inconvenient for handling, as it did not flow down at all in the popper of the extruder, causing starvation of the polymer in the extruder and causing decomposition.

[Example 2 and Comparative Example 2] 3.0 mol of lithium acetate dihydrate was used instead of 3.0 mol of sulfur and lithium benzoate in Example 1.
, a similar dehydration tripolymerization operation was performed. From the end of polymerization at 260°C for 22 hours, the system was heated at a rate of 0.5°C/min to 100°C.
After slowly cooling to ℃, the autoclave was opened and the contents were poured into water, and the precipitated flaky polymer was collected and washed repeatedly with hot water. The obtained polymer had 4,400 voids, a bulk density of 0.31 t</lcc, and the size of microcrystals measured by X-rays was 87.

This polymer has almost no bridge formation and has good fluidity.1. Very easy to handle! It was a convenient shape.

On the other hand, for comparison, a pulp-like polymer that was immersed in water from the bottom of the kettle and rapidly cooled as in Comparative Example I was prepared by 45 people with a crystallization rate of 0. It had a bulk density of OI IT /cc, and was a bulky polymer with very poor fluidity as a powder, making it inconvenient to handle.

Agent: Patent Attorney Takehiko Matsumoto

Claims (1)

[Claims] (1) When producing polyphenylene sulfide by polymerizing an aromatic polyhalide in the presence of a sulfur source and an amide solvent, after the completion of the polymerization, the inside of the system is heated from 6V to 240℃.
Polyphenylene sulfite is characterized in that the polymer is precipitated into particles by slow cooling at a rate slower than 50°C/min until the temperature reaches a temperature of Manufacturing method