JPS59204657A - Polyphenylene sulfide composition - Google Patents

Abstract

PURPOSE:To provide a composition composed of a specific polyphenylene sulfide and an inorganic filler, preparable by a simple polymerization process in high reproducibility, and giving a molded article having excellent heat resistance, mechanical properties and color and free from emission of sulfur compound vapor. CONSTITUTION:(A) A polyphenylene sulfide derived from a monomer having >=3 halogen atoms in one molecule, having the branching and/or crosslinking ratio of 0.3-3mol%, preferably 0.4-2mol%, an ionic iron content of <=0.3wt%, a melt viscosity of 500-20,000 poise, a non-Newtonian index of 1.2-2.0, and a 4,4'- dichlorodiphenyl ether content of <=0.1wt%, preferably <=0.07wt%, is compounded with (B) 5-80wt% of an inorganic filler. The molar ratio of p-dihalobenzene to the sulfur source in the polymerization of the polyphenylene sulfide is preferably 0.93-12.0.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to compositions obtained from branched and/or cross-linked polyphenylene sulfide and inorganic fillers without oxidative crosslinking.

[Prior art]

Conventional polyphenylene sulfide compositions for molding are made by heating a polymer with a low degree of polymerization in an oxidizing atmosphere to cause branching and cross-linking to increase the apparent melt viscosity. Compositions with added fillers are known.

However, such conventional polyphenylene sulfide compositions have a large influence on the ionic iron content, water content during polymerization, and basicity (as a measure of the As a result, oxidative curing of prepared polymers was used as the base polymer without paying any attention to matters such as specifying specific ether compounds, resulting in the generation of sulfur-based gases when made into molded products. In many cases, they tend to have poor heat resistance and poor mechanical properties. Furthermore, since it employs a process called curing that is difficult to control, it also has the disadvantage that the melt viscosity is not reproducible.

On the other hand, a method has been proposed in which an auxiliary agent is used during bipolymerization to obtain high molecular weight polyphenylene sulfide with less branching and crosslinking, but a large amount of auxiliary agent is generally required and it is difficult to remove it from the polymer. This method has drawbacks such as increased handling of raw materials and complexity.

[Purpose of the invention]

The object of the present invention is to provide a polyphenylene sulfide composition that does not have the above drawbacks, that is, the polymerization process is simple and reproducible, and the molded product has excellent heat resistance, two mechanical properties, two color tones, and little generation of sulfur gas. We aim to provide the following.

[Structure of the invention]

The present invention is directed to monomers having 6 or more halogens in 2 molecules, and/-1: 03 to 6
It has a molar range, an ionic iron content of 06% by weight or less, and a melt viscosity of 500 to 20,000 poise.

Non-Newtonian index ranges from 1.2 to 6.0, 4.4
'Polyphenylene sulfide with a dichlorodiphenyl ether content of 0.1% by weight or less and an inorganic filler
It features a polyphenylene sulfide composition containing ~80% by weight.

The polyphenylene sulfide in the present invention is.

Its main component is the general formula -4-8→ as its structural unit. If the main component is less than 70 molar, the crystallinity of the resulting polymer may be reduced.

This results in unfavorable results such as a low transition temperature and deterioration of physical properties such as heat resistance and mechanical properties when molded. Any unit that can be linearly copolymerized may be used as long as it is less than 60 moles of the main component and the other components. Examples of such copolymerizable units include m-phenylene sulfide,
2,6 naphthalene sulfide, diphenyl sulfone sulfite, biphenyl sulfide, bibenzyl sulfide)
", 2.5 dimethyl phenyl sulfide, etc.

Sulfide, do units containing an aromatic group having 6 or more carbon atoms are preferred.

Furthermore, in the present invention, in order to give polyphenylene sulfide a branched, /l- or cross-linked structure in the polymerization step, it is necessary to use a monomer having six or more halogens in the molecule. The amount of branching and/or cross-linking resulting from the use of the monomer is based on the structural unit fi 0.5~
3 mol%, preferably 0.4 to 2 mol%. If the amount of branching and/or bridging is too large, the viscosity at the time of melting will rise too much and the flowability will deteriorate; conversely, if the amount is too small, melt molding 11. It is difficult to obtain a polymer with sufficient viscosity for . It is convenient to use the non-Newtonian index at the time of melting as an index of fluidity. Non-Newtonian exponents are ramifications”!
This value varies depending on the degree of crosslinking and the molecular weight, but this value is 12 to 3.0 and 16 to 2.
A value in the range of 5 is desirable; if it is smaller than this range, the strength during melting is likely to be low, and if it is larger than this range, the fluidity will be poor and it will be difficult to obtain a molded product with fine details. The non-Newtonian index is defined by the following formula.

・±0 γ = τ μ Here, γ shear rate (seconds) 1 μ is viscosity (poise),
τ represents shear stress (pull/mm2), and n represents a non-Newtonian index.

In addition, in view of the fluidity during molding, the polyphenylene sulfide of the present invention has a melting viscosity at a shear rate of 300 (seconds) and a shear rate of 200 (seconds). 500~200DC) Boise preferably 800~
15,000 Poise Rukakai ≠≠ Yushina. If the viscosity is too low, the melt strength will be low, and if the viscosity is too high, the fluidity will deteriorate, which is undesirable.

The polymerization process of polyphenylene sulfide of the present invention will be explained.

Polyphenylene sulfide is obtained by disulfidizing p-dihalobenzene using a sulfur source in a solvent containing an aprotic amide bond. It is characterized in that the polymerization is carried out in the absence of halogen, and branching and/or cross-linking is caused by a monomer having a hexafunctional or higher halogen. As a solvent having an aprotic amide bond, N-methylpyrrolidone is used.

Examples include N-ethylcaprolactam, NN-dimethylimidazolidinone, NN-dimethylacetamide, and hexamethylphosphoramide, with N-methylpyrrolidone being preferred. Examples of p-dihalobenzene include p-dibromobenzene, p-dichlorobenzene, p-difluorobenzene, and p-chlorobromobenzene, with p-dichlorobenzene being preferred.

Examples of monomers having a hexafunctional or higher functional group that cause branching and/or crosslinking include L2,4) dichlorobenzene + L2,6) dichloronaphthalene.

1, 2.4.5 tetrachlorobenzene, 3, 4.4')
Examples include lychlorbiphenyl. These polyfunctional monomers Up-dihalobenzene can be added to the system at the same time, or p-dihalobenzene can be added to the system during the initiation of polymerization, or just before or after the end of polymerization to cause a reaction. The amount used must be sufficient to cause branching and/or crosslinking of 0.3 to 3 mole to the polyphenylene sulfide, but it is usually preferably from 0.6 to 10 mole to p-dihalobenzene. The amount of branching and/or cross-linking can be expressed as the amount of residue obtained by subtracting the amount of unreacted monomer recovered after the completion of polymerization from the amount of polyfunctional monomer used in the polymerization process.

Molar ratio of p-dihalobenzene and sulfur source during polymerization.

is preferably used in the range of 096 to 1.20 (excess of p-dihalobenzene); if it is out of this range, the polymer may decompose or the molecular weight of the obtained polymer may be too low.

As the sulfur source used in the polymerization step of the present invention, alkali sulfide, alkali hydrosulfide and alkali metal, metal bases, hydrogen sulfide and alkali metal base, etc. can be preferably used, and sodium sulfide and sodium hydrosulfide are more preferable. Hydroxide and hydroxide are sodium carbonate, hydrogen sulfide and hydroxide or sodium carbonate, etc. Among these, sodium sulfide and other sulfur sources are
It is convenient to use itu to form sodium sulfide.

It is desirable to perform polymerization by removing water from the polymerization system prior to adding p-dihalobenzene or a polyfunctional monomer, and water contained in the form of hydrate in the sulfur source or water generated during sodium sulfide adjustment is preferably carried out. can be removed by methods such as distillation, extraction, and adsorption, but removal by distillation is convenient.

If moisture or free alkali is released during polymerization, the thermal stability and properties of the resulting polyphenylene sulfide will be poor (9). Here, alkali in a free state means an alkali present in excess of the equivalent to form alkali sulfide.9 For example, when 1.0 mole of thorium bisulfide and 106 moles of sodium hydroxide are used, 0.03
Mol of sodium hydroxide means free alkali.

If polymerization is carried out in a highly watery or highly basic state (a state with a large amount of free alkali), oxygen is not easily introduced into the polymer as a result of alkaline hydrolysis of p-dihalobenzene and subsequent condensation. 4, 4'
The amount of dichlorodiphenyl ether is increased, and by using this amount as a measure, it is possible to judge whether the polymerization was carried out to produce undesirable polyphenylene sulfide, and only excellent compositions can be selected. 4,4' dichlorodiphenylny7-/lz (7) Content is polyphenylene sulfite 01% by weight or less, preferably 007%
It is as follows.

Although it is unlikely that this substance will directly degrade polyphenylene sulfide, polymers prepared under conditions where this substance is generated during preshocks have poor stability and physical properties. Alternatively, the oxygen content in the polymer (including oxygen-containing substances such as high molecular weight ethers) can be considered to be preferably 0.07% by weight or less. The residual water content during polymerization is less than 910 molar equivalents per sulfur source, preferably 0.2 to
A range of 0.095 molar equivalents is desirable. Further, it is desirable that the alkali in the free state is less than 0.5 molar equivalent, preferably less than 0.6 molar equivalent, relative to the sulfur source.

Polymerization at 200-300°C, preferably 260-290°C
It is preferable to carry out the heating for 1 to 10 hours, preferably for 2 to 6 hours, and any schedule may be used for raising and lowering the temperature within this range. After the polymerization is completed, the polymer is recovered by removing the solvent from the system by distillation or the like, then cleaning the system by re-precipitating it in water, etc., and then recovering and drying it. At this time, it is also possible to extract with an organic solvent neutralized with an acid.

The polyphenylene sulfide of the present invention is manufactured.

The apparent amount is increased by using a polyfunctional monomer, and the use of an auxiliary agent that linearly increases the molecular weight is not necessarily required. Therefore, when a commonly used iron-based polymerization tank is used, iron content is eluted more than when using high polymerization degree polyphenylene sulfide using an auxiliary agent. Among the iron contents, it is particularly undesirable that there is a large amount of ionic iron, that is, iron that forms carboxylates, hydroxides, sulfides, etc., as it is unlikely to have an adverse effect on coloring and deterioration of the molded product. Such ionic iron is 06
The content below the weight level is preferably 0.2 times the weight. The iron content in the polymer is affected by the amount of water during polymerization, the material of the basic 9 polymerization tank, the temperature conditions for bipolymerization, etc., but the moisture content and conditions for basic bipolymerization can be kept within the ranges already mentioned. preferable. The material of the polymerization tank is titanium.

It is preferable to use chromium, nickel, molybdenum, tungsten, or iron-based so-called stainless steel containing a large amount of these. If the complexity of the polymer recovery process is ignored, it is also possible to reduce the iron content to some extent by increasing the number of washings and the washing temperature.

From a chemical standpoint, the polyphenylene sulfide of the present invention is an inorganic filler that has not undergone branching and/or crosslinking through complex curing.

It is particularly compatible with inorganic substances having -8iO- bonds.

When used together with these fillers in a composition to produce a molded article, it is easy to obtain a molded article with excellent properties.

Examples of the inorganic filler having -8iO- bonding units include glass fiber, glass nonwoven fabric, glass beads, glass powder, talc, quartz powder, mica, feldspar powder, colloidal silica, and silicone resin.

Examples of other inorganic fillers include carbon fiber, iron oxide, and zinc oxide. These rolling fillers are surface-treated with various coupling agents, and too much of these fillers is undesirable because they tend to give brittle molded products.

The filler can be mixed in the powdered state of the polymer or in the molten state.

Also included in the composition of the present invention are colorants and antioxidants.

There is no problem even if additives such as ultraviolet absorbers are contained.

〔Effect of the invention〕

The present invention provides polyphenylene sulfide which has a branched and/or cross-linked structure without oxidative hardening, has a low content of iron and a specific ether compound, and has excellent fluidity.
It is characterized by a composition in which an inorganic filler coexists, and it is possible to obtain the following excellent effects.

(1) Heat resistance 2 Molded products with excellent mechanical properties can be obtained.

(2) The polymerization process of polyphenylene sulfide is simplified and a polymer with good reproducibility can be obtained.

(3) The color tone of the molded product is excellent.

(4) Less sulfur-based gas is generated during heating.

Due to the above-mentioned excellent characteristics, the composition of the present invention can be formed into sheets by extrusion, compression, injection, transfer molding, etc.
Can be molded into fibers, molded products, etc.

For example, it can be used for parts of automobiles and electrical appliances, connectors, switches, backings, etc.

The characteristics measurement method and evaluation criteria in the present invention are as follows.

(1) Melt viscosity, using a non-Newtonian exponent type flow tester with 2 caps and 1 dish φx10-
Measurements were made at 00°C. The melt viscosity was measured under a shear rate of 200 s-1, and the non-Newtonian index was calculated from the shear rate and shear stress (both logarithms).

(2) Content of 4,4' dichlorodiphenyl ether Polymer IDg was soaked and extracted in an extractor under reflux of diacetone for 8 hours, and the substance in the extract was quantified by gas chromatography. The column was packed with SE, 50
Shimadzu's GC-
This was done using 4BPT'F. In addition, the total oxygen content was determined by elemental analysis.

(3) Iron Content After the polymer was carbonized with a burner, it was incinerated in an electric furnace at 550'a for 7 hours, and the iron content contained in the ash was analyzed by atomic absorption spectrometry.

〔Example〕

An embodiment of the present invention will be described below with reference to Examples.

Examples 1-2. Comparative Examples 1 to 2 5 mol of sodium sulfide nonahydrate and 161 N-methylpyrrolidone were placed in a 51-sized autoclave and heated to 200°C while stirring under a nitrogen stream, and then placed in a rectifying tube having a triple tube and a Raschig ring filling. 740-750m after dehydration
A distillate consisting mostly of water containing some solvent of z (the same operation was carried out 4 times) was obtained. The amount of water remaining in the polymerization system was back calculated by measuring the solvent in the distillate using a gas chromatograph. The system after distillation is 17
Cool to 0°C and add 49 moles of p-dichlorobenzene to 0. 0.8. 1.4. 5 mol% of 1.2.
4) Charge 250 m of dichlorobenzene with 2 N methyl pyrrolidone and add nitrogen to the system at 21 cg/crn2.
Sealed in.

After the polymerization was completed, the system was cooled, the contents were poured into water, and the precipitated polymer was collected by filtration, washed with hot water repeatedly, and dried to obtain white polyphenylene sulfide.
...40 weight ratios of Asahi Fiberglass's "Glasron" chopped strand) 03JA429 were mixed with 4 types of polymers, and 2[
) mmφ diameter injection molded material, cylinder 310℃,
A 6 x 6 x 70 square bar was molded in a mold at 135°C, 2 pressure cuff, 50 kg, /2. Table 1 shows the properties of the polymer and the properties of the molded product.

As is clear from the above table, fluidity (polymer viscosity and non-Newtonian index) due to monobranching and/or crosslinking
In comparative examples outside the present invention, even if the iron content and 4.4' dichlorodiphenyl ether content were kept low, the heat resistance of the molded product was 2.
It was found that color tone 9, mechanical properties, etc. were inferior to those of the present invention.

Comparative Examples 6 to 5 These comparative examples are examples of polymers whose iron content and 4,4' dichlorodiphenyl ether are outside the range even though branching and /'=1: or crosslinking is within the range of the present invention. Examples are given for polymers whose viscosity increases upon curing even if these contents are within the range.

Polymerization was carried out in the same manner as in Example 1, but the amount of distillation from the double polymerization system was stopped at 350 ml, and the subsequent polymerization was carried out.

Separately, 6 mol of sodium hydroxide was added at the same time as sodium sulfide nonahydrate, and the distillation amount was stopped at 400 mJ to carry out polymerization. These conditions and both 1, 2.
A gray polymer was obtained by polymerization and recovery in the same manner as in Example 1, except that 2.5 mol% of 4-trichlorobenzene was used. The polymer was separated during washing with water by centrifugation using a Patetron cloth having a mesh size of about 10 μm.

Separately, the polymer obtained in Comparative Example 1 was cured by heating it in air at 200° C. for 60 hours.

In the same manner as in Example 1, 40 weight fractions of the same glass fibers were mixed with these six types of polymers and molded in the same manner. The results are shown in Table 2.

As is clear from the above table, it was found that the polymer compositions containing a large amount of iron in the polymer ether compound and the polymer compositions obtained by curing were inferior in mechanical properties, heat resistance, etc.

In the autoclave of Example No. 51, 5 mol of sodium hydrogen sulfide dihydrate and a 50% concentration sodium hydroxide aqueous solution 4002;
Add 1 iJ of N-methylpyrrolidone, dehydrate using the same rectification tube as in Example 1, and heat to 220'C.
A distillate of mj) was obtained, and 20 mz was a solvent. After cooling the system to 180'C, 4.655 moles of p
Dichlorobenzene, 0.245 mol of 2,5 dimethyl p-dichlorobenzene, 005 mol of 1,2,4.5 tetrachlorobenzene was added together with 250 ml of N-methylpyrrolidone and 1.0 kg/QT+2 under nitrogen flow. 2 hours at 260℃, 1 hour at 260℃,
Polymerization was carried out at 270°C for 60 minutes with stirring. After completion of polymerization, the system was poured into water, and the precipitated polymer was collected by filtration, washed repeatedly with hot water, and dried to obtain white polyphenylene sulfite. Add 200 mesh to this polymer. Filter the fine powdered talc that has been separated by weight.
10% of the glass fiber used in Example 11 was mixed and molded using the same molding machine under the same conditions. Table 6 shows the properties of the pots, the properties of the molded product, etc.

Table 6 As is clear from the above table, the polyphenylene sulfide composition of the present invention was found to be excellent in heat resistance, mechanical properties of molded articles, color tone, gas generation, etc.

Claims (1)

[Claims] (1) Branched and/or crosslinked by a monomer having 6 or more halogens in the molecule from 0.3 to 6 mol%, ionic iron content of 0% by weight or less, melt viscosity of 500% ~20000 poise, non-Newtonian exponent 12
A polyphenylene sulfite composition characterized by containing polyphenylene sulfide having a 4.4' dichlorodiphenyl ether content of 0.1 to 3.0% by weight or less, and an inorganic filler of 5 to 80% by weight. .