JPS59217728A - Purification of polyphenylene sulfide - Google Patents

Abstract

PURPOSE:To carry out the purification of a polyphenylene sulfide containing impurities such as electrolyte components, in an extremely short time, in high efficiency, by heating the crude sulfide in an organic amide solvent in the presence of a specific alkylphenyl formaldehyde condensate. CONSTITUTION:(A) A polyphenylene sulfide containing impurities consisting of electrolyte components such as NaCl, etc. is purified by heating the crude sulfide in (B) an organic amide solvent such as N-methylpyrrolidone, in the presence of (C) one or more alkylphenyl formadldehyde condensates of formula (R<1> is 2-4C alkylene; R<2> is H, 1-30C alkyl or aryl; m and n are average degree of polymerization, and are 2-50 and 0-90, respectively), thereby decreasing the content of the above electrolyte components. EFFECT:A sufficiently purified resin applicable to electronic parts can be prepared by this process.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel and useful method for purifying polyphenylene sulfide, and more particularly to a method comprising heat treatment in the presence of an alkylphenyl formaldehyde condensate.

Polyphenylene sulfide (hereinafter abbreviated as "PP5J") is produced by injection molding or extrusion molding,
By melt-molding engineering plastics, films, or fibers, it is widely used to make various molded products that take advantage of their heat resistance and chemical resistance.

As a general method for producing PPS, a method in which an aromatic halide such as p-dichlorobenzene is reacted with sodium sulfide in an organic amide solvent has already been described in Japanese Patent Publication No. 3368/1983, and , high degree of polymerization P
As an improved polymerization reaction method for obtaining Ps, the addition of an alkali metal carboxylate as a polymerization aid is also disclosed in Japanese Patent Publication No. 52-12240.

Separately, when such PPS is applied to films, fibers, or various electrical or electronic parts, it is necessary to include in the polymer in order to maintain the inherent moldability and electrical insulation properties of PPS. Inorganic electrolyte impurities such as common salt (NaC1) (also called ash).

) is desirable to be as small as possible.

In particular, when used as a coating or sealing material for electronic components such as PPS'QIC transistors or capacitors, the electrodes and wiring of these components may be corroded or disconnected. However, in order to prevent such troubles from occurring, it is absolutely necessary to use a polymer with as few electrolyte impurities as possible, as described above. becomes.

By the way, in the case of the pps production method as described above, as a result of the fact that almost the same amount of common salt as the produced polymer is produced and precipitated as a by-product, the amount of salt in the polymer obtained only by ordinary processing is unavoidable. contains a considerable amount of remaining common salt, so a resin composition obtained using pps with a high content of electrolyte impurities has a lower content than one using pps with a low content of electrolyte impurities. However, it has the disadvantage that its electrical characteristics are significantly inferior.

Therefore, as a final measure to eliminate these defects and improve the electrical characteristics, the pps powder obtained through normal processing is eluted again by boiling in hot water for a long time with deionized water. A method of reducing impurities as much as possible is also described in JP-A-55-156342.

However, according to the research of the present inventors, when reducing impurities by the extraction method using hot water boiling as described above, it not only takes an unnecessarily long time; The content of impurities has also not been reduced as much as expected, and the drawback that no matter how many times or tens of times the extraction operation is repeated, a polymer with higher purity cannot be obtained has been eliminated. There wasn't,
On the other hand, the inorganic components in the PPS can be removed by heating a mixture of PPS and alkali metal carboxylate-t and lithium halide in an organic amide solvent, as disclosed in U.S. Pat. No. 4,071,509. Even if 51 methods were used to reduce the content, the PPS purified by any of these methods was still satisfactory for use as a coating or sealing material for electronic components. There was a lot of purity.

However, as described above, the present inventors have been conducting intensive studies to overcome the drawbacks of various conventional purification methods and establish a useful purification method. When a specific alkylphenyl formaldehyde condensate was used as an agent), only impurities consisting of electrolyte components containing sodium ions could be removed without any decomposition of the polymer itself, and the content of such inorganic electrolyte impurities could be reduced within an extremely short period of time. The present invention has been completed based on the discovery that it is possible to efficiently reduce the amount of carbon dioxide.

That is, the present invention consists of heat-treating an impurity consisting of an inorganic electrolyte component containing metal ions in an organic amide solvent in the presence of an alkylphenyl formaldehyde condensate represented by the following general formula A-6. The object of the present invention is to provide a method for obtaining extremely high-purity pps, which can efficiently reduce the impurity content by removing only the above-mentioned impurities without decomposing the polymer.

(In the formula, R1 is an alkylene group having 2 to 4 carbon atoms, R2
is hydrogen, or an alkyl group and/or an aryl group having 1 to 30 carbon atoms, and m and n indicate an average degree of polymerization, each of which is 2 to 50.0 to 90.

) In carrying out the method of the present invention, PP used first
For S, the MI (melt index) value measured according to the method of A8TM D1258-70, that is, the value measured at a load of 5 kg and a temperature of 315.6°C (600°F), is 10000 (9710 minutes) or less. , Arui heated a sample with a polymer solution concentration with an intrinsic viscosity of 0.4 g/100 d in α-chlornaphthalene at 206°C (403°C).
The value obtained by dividing the natural logarithm of the "relative viscosity value" based on the viscosity measured in F) by the "polymer concentration", that is, the value calculated by the following formula, and the value when the polymer concentration is set to infinitesimal, that is, "zero". A PPS with a value of 105 or more is suitable.

In addition, PP used in carrying out the method of the present invention
If s contains 70 mol% or more, preferably 90 mol% or more of a structure having a repeating unit represented by the following formula, it may be copolymerized with other components, or a part thereof. It is a thermal theory that it can be used even if it has a branched structure or a structure in which a part of it is crosslinked.

Typical copolymer components in this case include 9- There are cap-replacement sulfide units as shown in .

Furthermore, in carrying out the method of the present invention, the PPS used is the electrolyte impurity contained in the polymer! # is optional and there is no particular limitation, but at least 0.1%, for example, sodium ions may be included as an electrolyte component.

The above-mentioned pps is the special public service published in 1986-336 as mentioned above.
It can be produced according to the method of the invention described in Publication No. 8 and Publication No. 52-12240.

On the other hand, the aforementioned organotylacetamides, 2-pyrrolidone, formamide, acetamide, 6-caprolactam, N-methylcaprolactam, tetramethylurea or 1,3-dimethyl-2 used in carrying out the process of the invention
-Imi=10- There are dasylidinones, but two or more of these may be used as a mixture, and among these, N-methylpyrrolidone is particularly preferred.

The amount of the organic amide solvent used is preferably in the range of 1 to 20 parts by weight per 1 part by weight of the above-mentioned PPS.

In the method of the present invention, the following general formula A is used as an additive for separating and removing impurities such as common salt from the PPS polymer.
It is necessary to use an alkylphenyl formaldehyde condensate represented by

(In the formula, R1 is an alkylene group having 2 to 4 carbon atoms, R1
is hydrogen or an alkyl group and/or aryl group having 1 to 30 carbon atoms, m and n represent the average degree of polymerization, and examples of R' in the above general formula include -CH, C
Examples of H2-1 include hydrogen, methyl group, ethyl group, butyl group, octyl group, nonyl group, dodecyl group, cetyl group, 1-methylheptyl, 2-ethylhexyl, 1-methyl-4-ethyloctyl, etc. Alkyl group; alkylaryl group such as ethylphenyl group and dodecylphenyl group;
Examples include aryl groups such as phenyl group and naphthyl group. Specifically, the compound represented by the above general formula A is:
polyoxyethylene phenyl formaldehyde condensate,
Polyoxyethylene methylphenyl formaldehyde condensate, polyoxyethylene nonylphenyl formaldehyde condensate, polyoxyethylene cetyl phenyl formaldehyde condensate, polyoxypropylene methyl phenyl aldehyde condensate, polyoxypropylene nonylphenyl aldehyde condensate, polyoxybutylene nonylphenyl Examples include aldehyde compounds, phenol formaldehyde condensates, nonylphenol formaldehyde condensates, and mixtures thereof.

The appropriate amount of the alkylphenyl formaldehyde condensate of Cholera to be used is 0.01 to 200% by weight, preferably 0.5 to 100% by weight, based on pps.

When carrying out the method of the present invention, if necessary, an alkali metal salt of an organic acid can also be added, but this is for preventing the decomposition of pps or conversely increasing the molecular weight. Typical examples of such metal salts include compounds represented by the following general formula % (), among which representative examples include lithium acetate, sodium acetate, sodium benzoate, and benzenesulfonic acid. Sodium, sodium p-toluenesulfonate, sodium α-naphthalenesulfonate, disodium succinate, disodium adipate, disodium phthalate, trisodium sulfophthalate, disodium naphthalene disulfonate or trisodium trimellitate, etc. However, these alkali metal salts may be anhydrous salts or hydrates.

Furthermore, alkaline earth metal carbonates such as lithium carbonate and sodium carbonate, or alkali metal halides such as lithium chloride and lithium bromide can also be used, and they can also be used in combination with the alkali metal salts of organic acids mentioned above. .

And, use 1 of the alkali metal salt is 1 of the pps.
0.05 to 4 mol, preferably 0.1 to 4 mol relative to 0DI
A range of 2 moles is appropriate.

In addition to the various PPS mentioned above, the method of the present invention also uses PP in the form of a blend of various other polymers.
Typical examples of such other polymers include polysulfone, polyether sulfone, polyphenylene oxide, polyether ether ketone, polycarbonate, polyethylene, polyamide, polyester, polyimide, and polyether. be.

Therefore, in order to purify the PPS according to the method of the present invention, the PPS containing an inorganic electrolyte component consisting of, for example, at least 0.1% by weight of sodium ions in the above-mentioned organic amide solvent (!: , the above-mentioned alkylphenyl formaldehyde condensate, and, if necessary, the mixture with the above-mentioned alkali metal salt, usually at 100 to 650°C.
, preferably at a temperature of 200 to 280°C, usually 01 to 1
The heat treatment may be carried out under stirring for 0 hours, preferably 0.5 to 4 hours, and through such treatment operations, the content of IJium ions can be significantly increased without causing any decrease in the molecular weight of PPS. It can be reduced.

The pressure within the system at that time may be appropriately selected so as to be within a range sufficient to maintain the organic amide solvent in the liquid phase.

The heat-treated mixture can then be recovered by conventional procedures, such as filtering the mixture and subsequently washing the polymer with water, or diluting the mixture with water and filtering the mixture followed by washing the polymer with water. I can do it. Alternatively, the organic amide solvent can be recovered from the mixture by distillation and/or flashing before washing with water. Thereafter, highly pure PpS can be isolated by washing the polymer with water and drying it.

Thus, the pps obtained by the method of the present invention contains almost no impurities consisting of inorganic electrolyte components such as common salt, and
Since it is of extremely high purity, it maintains the good electrical insulation properties inherent to PPS.

Therefore, PPS obtained by the method of the present invention can be used not only to obtain various molded products such as films and fibers, but also to obtain molded products such as various electrical or electronic parts. Since the pps obtained by the above method contains almost no electrolyte components that would corrode the electrodes and wiring parts of electronic components, It is extremely useful as a coating or sealing material not only for individual electronic parts such as capacitors, but also for composite electronic parts.

Next, the present invention will be specifically explained using Examples and Comparative Examples.

In addition, in the following, the intrinsic viscosity [η] of PPS is 0.4
At a polymer solution concentration of fl/1001117,
It was measured at 206°C (400°F) in α-tetralunaphthalene and calculated according to the above formula [[],
On the other hand, the sodium ion content in PPS was measured as follows. That is, a polymer is thermally decomposed together with nitric acid in a platinum crucible, and the sodium content in the decomposed liquid is measured using an atomic absorption photometer.
The flame intensity is measured using an acetylene flame and a measurement wavelength of 589 nm. The content of sodium ions in PPS is calculated by comparing with a calibration curve prepared using a commercially available standard solution of IJ chloride.

[Example 1] In a 51 autoclave equipped with a stirrer, 1991 of N-methylpyrrolidone and 537I of sodium sulfide hemihydrate were added.
I (4.1 mol), 1.6 N of sodium hydroxide (
0.04 mol) and 144II (1
.

Next, after cooling the reaction system to 150°C, 603.9 (4.1 mol) of p-dichlorobenzene and 250g of N-methylpyrrolidone were added, and the mixture was heated at 230'C for 2 hours and then at 260'C for 3 hours. During the reaction, the internal pressure at the end of the polymerization reaction was 9.0 kg/d.

Thereafter, the autoclave was cooled and the contents were separated, and the cake (solid content) was washed three times with hot water, further washed twice with acetone, and then dried at 120°C.
412 g of pale gray-brown granular pps was obtained (yield =
96%).

The intrinsic viscosity [η] of the PPS obtained here is 0.27,
And the content of sodium ions was 1230 ppm.

Next, 20 g of PPS of
,, 2.0 g with average degree of polymerization m = 3 and n = 8)
and benzoic acid) IJum 26.6fi (0,185
Mol) and 200I of N-methylpyrrolidone were charged into a 11 autoclave equipped with a stirrer, heated under a nitrogen atmosphere, and continued to be heated to 265°C for 2 hours while stirring, but the internal pressure at the end of heating was 2.8 kg. /crl.

After that, the autoclave was cooled, the contents were poured out, and the cake (solid content) was soaked three times in hot water and then twice in acetone.
When the polymer was recovered after washing twice, a polymer of 2011 was obtained, and the intrinsic viscosity of this polymer was 0.2.
9, and the sodium ion content was 12 ppm.

As described above, when the method of the present invention is followed, not only is the content of impurities consisting of sodium ions in PPS significantly reduced, but there is also no decomposition of the polymer, which is preferable in that the molecular weight is slightly increased. The results were approved.

[Example 2] In the step of purifying the polymer obtained by the polymerization of Example 1, the same operation as in Example 1 was repeated except that benzoic acid (IJ) was not used, and the final product was obtained. Polymer 21-17z had an intrinsic viscosity of 0.24 and a sodium ion content of 8 ppm.

This shows that the same effect can be expected even in the absence of sodium benzoate, and shows that the method of the present invention is an excellent method.

[Comparative Example 1] The same operation as in Example 1 was carried out, except that both the polyoxyethylene nonylphenyl formaldehyde condensate and sodium benzoate were completely absent in the step of purifying the polymer obtained by polymerization in Example 10. I repeated,
The finally obtained polymer had a low intrinsic viscosity value of 0.17, and a still high sodium ion content of 570 Ppffl.

[Comparative Example 2] The same operation as in Example 1 was repeated, except that in Step 22-- of purifying the polymer obtained by the polymerization of Example 1, the polyoxyethylene nonylphenyl formaldehyde condensate was not used. However, although the intrinsic viscosity of the final polymer was as high as 0.29, the sodium ion content in this polymer was still 590 ppm.
It wasn't something to be satisfied with.

[Examples 3 to 13 and Comparative Example 3] Instead of sodium benzoate, 418 g (4.1 mol)
using lithium acetate dihydrate and 1.8Ii (0.01 mol) of 1.2.4 as a polyhaloaromatic compound.
The polymerization reaction was carried out in the same manner as in Example 1, except that -trichlorobenzene was added and the amount of N-methylpyrrolidone was increased to 310 g.
0d, the internal pressure at the end of polymerization was 9.6 kl/l-, and the yield and yield of pale gray-brown granular pps were 394.
g and 89%, and this PPS has an intrinsic viscosity value of 0.34 and a sodium ion content of 860 ppm.
Met.

Hereinafter, only Example 3 was carried out in the same manner as in Example 1, while Examples 4 to 13 were carried out in the same manner as in Example 1 except that the compounds and their usage amounts were changed as shown in Table 1. Example 6 was carried out in the same manner as Comparative Example 1.

The results for each of these cases are shown in Table 1.

Claims (1)

[Claims] Polyphenylene sulfide containing impurities consisting of electrolyte components is heated in an organic amide solvent in the presence of at least one compound selected from the group of alkylphenyl formaldehyde condensates represented by the following general formula A. A method for purifying polyphenylene sulfide, the method comprising: reducing the content of the electrolyte component. (In the formula, R1 is an alkylene group having 2 to 4 carbon atoms, R2
is hydrogen or an alkyl group and/or an aryl group having 1 to 30 carbon atoms, and m and n indicate an average degree of polymerization, each being 2 to 50.0 to 90. )