JPH08134354A - Polyarylenesulfide resin composition - Google Patents

Abstract

PURPOSE: To obtain a resin composition containing a specific polyarylenesulfide and potassium titanate whisker at a specific ratio, excellent in abrasion resistance and sliding characteristics and suitable for sliding members such as gear. CONSTITUTION: This resin composition contains (A) 100 pts. wt. of a polyarylene sulfide produced by reacting an alkali metal sulfide with a dihalo-aromatic compound such as p-dichlorobenzene in an organic amide-based solvent such as DMF, cooling a vapor phase part of a reactor during reaction, condensing a part of vapor phase in the reactor and refluxing the condensed material to a liquid phase and (B) 10-200 pts.wt., preferably 40-100 pts.wt. of potassium titanate whisker having preferably 0.5-1.5μm average fiber diameter and preferably 5-70 aspect ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyarylene sulfide resin composition, and more particularly to a polyarylene sulfide resin composition having excellent sliding characteristics such as abrasion resistance.

[0002]

2. Description of the Related Art Polyarylene sulfide (hereinafter referred to as P
(Sometimes abbreviated as AS) shows excellent resistance to acids, alkalis, various organic solvents, etc.
Excellent mechanical strength such as rigidity and electrical characteristics such as insulation resistance. Therefore, PAS is used for automobiles, machinery, and
Widely used in the electronic field.

However, it is difficult to use PAS alone in gears, rotating parts, etc. because of its poor sliding characteristics.

Conventionally, in order to solve such a problem, polytetrafluoroethylene (hereinafter sometimes abbreviated as PTFE), carbon fiber (hereinafter sometimes abbreviated as CF) and the like have been added to PAS. However, when PTFE is added, there is a problem that mechanical strength such as rigidity of the entire PAS resin composition is lowered, and when CF is added, the hue of the entire PAS resin composition is deteriorated and blackened. there were.

Various attempts have been made to solve the above problems. For example, in Japanese Patent Laid-Open No. 59-215353, P
A resin composition containing 5 to 70% by weight of potassium titanate fiber in AS is disclosed. JP 61-40357
Japanese Patent Laid-Open Publication No. 2005-242242 discloses that powdered polymer solid lubricant is added to PAS in an amount of 5 to 5.
A resin composition containing 20% by weight and 10 to 40% by weight of potassium titanate fiber as a fibrous reinforcing material is disclosed. Japanese Unexamined Patent Publication (Kokai) No. 63-205356 discloses a resin composition in which PAS contains at least one reinforcing material selected from heat resistant fibers or inorganic whiskers and ultra high molecular weight polyethylene powder. In addition, Japanese Patent Fair 5-2
No. 87200 discloses that 100 parts by weight of PAS is added to
Carbon fiber 80-140 parts by weight, spherical carbon 20-80
A resin composition composed of 10 parts by weight and 10 to 50 parts by weight of potassium titanate whiskers is disclosed. However, in any case, the present situation is that sufficient sliding characteristics have not yet been obtained.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a PAS resin composition which can be used for sliding parts such as gears and which has excellent sliding characteristics such as abrasion resistance.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above problems. As a result, a predetermined amount of potassium titanate whiskers was added to PAS produced by reacting an alkali metal sulfide with a dihaloaromatic compound in an organic amide solvent and cooling the gas phase portion of the reaction vessel during the reaction. It was found that the sliding characteristics of PAS can be remarkably improved by the addition of the above, and the present invention has been completed.

That is, according to the present invention, (A) an alkali metal sulfide is reacted with a dihaloaromatic compound in an organic amide solvent, and the gas phase portion of the reaction vessel is cooled during the reaction. Polyarylene sulfide 100 produced by condensing a part of the gas phase inside and refluxing it in the liquid phase
Parts by weight, and (B) potassium titanate whiskers 10
To 200 parts by weight.

As a method for producing PAS by cooling a gas phase portion of the reaction can of the present invention to condense a part of the gas phase in the reaction can and refluxing the condensed gas to a liquid phase, JP-A No. 5/1999 can be used.
The method described in JP-A-222196 can be used.

The refluxed liquid has a high water content compared to the liquid phase bulk because of the vapor pressure difference between water and the amide solvent.
This reflux liquid having a high water content forms a layer having a high water content on the reaction solution. As a result, the residual alkali metal sulfide (for example, Na ₂ S), alkali metal halide (for example, NaCl), oligomer and the like are contained in a large amount in the layer. In the conventional method, at a high temperature of 230 ° C. or higher, when the generated PAS and the raw materials such as Na ₂ S and by-products are uniformly mixed, not only high-molecular-weight PAS cannot be obtained but Depolymerization of PAS also occurred, and thiophenol by-product was observed. However, in the present invention, by positively cooling the gas phase portion of the reaction vessel and returning a large amount of water-rich reflux liquid to the upper portion of the liquid phase, the above-mentioned inconvenient phenomenon can be avoided and the reaction is inhibited. Of high molecular weight PA
It seems that S can be obtained. However, the present invention is not limited only to the effects due to the above-mentioned phenomenon, and high-molecular weight PAS can be obtained by various influences caused by cooling the gas phase portion.

In the present invention, it is not necessary to add water during the reaction unlike the conventional method. However, the addition of water is not excluded at all. However, some of the advantages of the present invention are lost if the operation of adding water is performed. Therefore, preferably, the total water content in the polymerization reaction system is constant throughout the reaction.

The gas phase portion of the reactor can be cooled by external cooling or internal cooling, and can be performed by a cooling means known per se. For example, a method of flowing a cooling medium into an internal coil installed in the upper part of the reaction can, a method of flowing a cooling medium into an external coil or jacket wound around the upper part of the outside of the reaction can, and a reflux condenser installed in the upper part of the reaction can are used. The method may be such as sprinkling water or blowing gas (air, nitrogen, etc.) on the upper part of the outside of the reaction can. Any method is effective as long as it has the effect of increasing the reflux amount in the can. May be used. If the outside air temperature is relatively low (for example, room temperature), it is also possible to perform appropriate cooling by removing the heat insulating material conventionally provided on the upper part of the reaction can. In the case of external cooling, water condensed on the reactor wall surface
The amide-based solvent mixture enters the liquid phase along the wall of the reaction vessel. Thus, the water-rich mixture pools on top of the liquid phase,
Keep the water content there relatively high. For internal cooling,
The mixture condensed on the cooling surface likewise travels along the surface of the cooling device or the wall of the reaction vessel into the liquid phase.

On the other hand, the temperature of the liquid phase bulk is maintained at a predetermined constant temperature or controlled according to a predetermined temperature profile. 230 to 275 for constant temperature
It is preferable to carry out the reaction at a temperature of ° C for 0.1 to 20 hours. More preferably, the temperature is 240 to 265 ° C. and the time is 1 to 6 hours. To obtain higher molecular weight PAS, it is preferable to use a reaction temperature profile of two or more steps. This 2
When carrying out the stepwise operation, the first step is preferably carried out at a temperature of 195 to 240 ° C. If the temperature is low, the reaction rate is too slow, which is not practical. If the temperature is higher than 240 ° C., the reaction rate is too fast, PAS having a sufficiently high molecular weight cannot be obtained, and the side reaction rate remarkably increases. The end of the first stage is
Dihalo aromatic compound residual rate in the polymerization reaction system is 1 mol% to 40
It is preferable to carry out at a time of mol% and a molecular weight in the range of 3,000 to 20,000. More preferably, the residual ratio of the dihalo-aromatic compound in the polymerization reaction system is 2 mol% to 15 mol% and the molecular weight is 5,000 to 15,000. Residual rate is 40 mol%
When it is more than 1, the side reaction such as depolymerization is likely to occur in the second step reaction, while when it is less than 1 mol%, the high molecular weight P is finally obtained.
It is difficult to get AS. Thereafter, the temperature is raised, and the reaction in the final stage is preferably carried out at a reaction temperature of 240 to 270 ° C. for 1 to 10 hours. PAS with sufficiently high molecular weight at low temperature
At a temperature higher than 270 ° C., side reactions such as depolymerization are likely to occur, making it difficult to stably obtain a high molecular weight product.

As an actual operation, first, dehydration or water addition is carried out in an inert gas atmosphere, if necessary, so that the amount of water in the alkali metal sulfide in the amide solvent becomes a predetermined amount. The water content is preferably alkali metal sulfide 1
The amount is 0.5 to 2.5 mol, especially 0.8 to 1.2 mol per mol. If it exceeds the above range, the reaction rate becomes small,
Moreover, the amount of by-products such as phenol increases in the filtrate after the reaction, and the degree of polymerization does not increase. If the amount is less than the above range, the reaction rate is too fast to obtain a sufficiently high molecular weight product.

In the case of the one-step reaction at a constant temperature, the cooling of the gas phase portion during the reaction is preferably performed from the start of the reaction, but it must be performed at least during the temperature increase of 250 ° C. or less. In the multi-stage reaction, it is preferable to perform cooling from the first-stage reaction, but it is preferable to perform cooling at the latest after the completion of the first-stage reaction. Regarding the degree of cooling effect, the pressure inside the reaction vessel is usually the most suitable index. The absolute value of the pressure varies depending on the characteristics of the reaction vessel, the stirring state, the water content in the system, the molar ratio of the dihalo aromatic compound to the alkali metal sulfide, and the like. However, as compared with the case of not cooling under the same reaction conditions, if the reactor pressure is decreased, the amount of reflux liquid is increased, which means that the temperature at the reaction solution gas-liquid interface is decreased. It is considered that the degree of relative decrease indicates the degree of separation between the layer having a high water content and the layer having no water content. Therefore, it is preferable to cool the reactor so that the internal pressure of the reactor becomes lower than that in the case where no cooling is performed. The degree of cooling can be appropriately set by those skilled in the art according to the equipment used, operating conditions, and the like.

The organic amide solvent used here is PA
Known for S polymerization, for example N-methylpyrrolidone (NMP), N, N-dimethylformamide,
N, N-dimethylacetamide, N-methylcaprolactam, etc., and mixtures thereof can be used, with NMP being preferred. They all have a lower vapor pressure than water.

Alkali metal sulphides are also known, for example lithium sulphide, sodium sulphide, potassium sulphide, rubidium sulphide, cesium sulphide and mixtures thereof. These hydrates and aqueous solutions may be used. Further, hydrosulfides and hydrates corresponding to these can be used after being neutralized with the corresponding hydroxides.
Inexpensive sodium sulfide is preferred.

The dihalo-aromatic compound is, for example, Japanese Patent Publication No.
It can be selected from those described in JP-A-5-3368, but is preferably p-dichlorobenzene. Further, a copolymer can be obtained by using a small amount (20 mol% or less) of one or more kinds of para, meta or orthodihalo compounds of diphenyl ether, diphenyl sulfone or biphenyl. For example, m-dichlorobenzene, o-dichlorobenzene,
p, p'-dichlorodiphenyl ether, m, p'-dichlorodiphenyl ether, m, m'-dichlorodiphenyl ether, p, p'-dichlorodiphenyl sulfone, m, p'-dichlorodiphenyl sulfone, m, m '
-Dichlorodiphenyl sulfone, p, p'-dichlorobiphenyl, m, p'-dichlorobiphenyl, m, m'-
It is dichlorobiphenyl.

In order to increase the molecular weight of PAS,
For example, 1,3,5-trichlorobenzene, 1,2,4-
A polyhalo compound such as trichlorobenzene can also be used in a concentration of preferably 5 mol% or less based on the total amount of para and metadihalo aromatic compounds.

Further, as a small amount of other additives, a terminal terminating agent and a monohalo compound as a modifying agent can be used in combination.

The component (A) PAS thus obtained is separated from by-products by post-treatment methods known to those skilled in the art.

In the present invention, the PAS obtained as described above is preferably further acid-treated. The acid treatment is preferably carried out at a temperature of 100 ° C. or lower, particularly preferably 40 to 80 ° C. If the temperature exceeds the above upper limit, the PAS molecular weight after acid treatment decreases, which is not preferable. On the other hand, if the temperature is lower than 40 ° C., the remaining inorganic salt is deposited to reduce the fluidity of the slurry and hinder the continuous treatment process, which is not preferable. The concentration of the acid solution used for the acid treatment is preferably 0.01 to 5.0% by weight. The pH of the acid solution is preferably 4.0 to 5.0 after the acid treatment. By adopting the above concentration and pH, most of the ends of -SNa and -COONa in the PAS to be treated are -SH and-.
It is preferable because it can be converted to a COOH terminal and the corrosion of plant equipment can be prevented. The time required for the acid treatment depends on the acid treatment temperature and the concentration of the acid solution, but it is preferably 5 minutes or longer, particularly preferably 10 minutes or longer. Below the above, -SNa and-in PAS
It is not preferable because the COONa terminal cannot be sufficiently converted to the -SH and -COOH terminals. For the acid treatment, for example, acetic acid,
Formic acid, oxalic acid, phthalic acid, hydrochloric acid, phosphoric acid, sulfuric acid, sulfurous acid, nitric acid, boric acid, carbonic acid and the like are used, and acetic acid is particularly preferable. By carrying out the treatment, sodium as an impurity in PAS can be reduced. By performing the above-mentioned acid treatment, sliding properties such as abrasion resistance of the resin composition can be further improved.

The component (B) potassium titanate whiskers can be prepared, for example, by the general formula K ₂ O.n (TiO ₂ ) or K ₂ O.
_{· N (TiO 2) · 1/2} (H 2 O) ( wherein, n 2
It represents a single crystal fiber. For example, 4-potassium titanate fiber, 6-potassium titanate fiber, 8-potassium titanate fiber, etc. may be mentioned, and these may be used alone or in a mixture of two or more. The potassium titanate whiskers have an average fiber diameter of preferably 2.0 μm or less, particularly preferably 0.5 to 1.5 μm,
The average fiber length is preferably 5 to 50 μm, particularly preferably 10 to 20 μm, and the aspect ratio is preferably 200.
Below, it is particularly preferably 5 to 70. These potassium titanate whiskers may be surface-treated with one or more silane coupling agents such as vinylsilane, epoxysilane, aminosilane and mercaptosilane.

In the resin composition of the present invention, the component (A)
10 to 200 parts by weight of the component (B) with respect to 100 parts by weight,
It is preferable to add 40 to 100 parts by weight. Ingredient (B)
If the value is less than the above range, the sliding characteristics of PAS are not improved, and if the value exceeds the above range, mechanical strength such as rigidity and impact resistance, which are the characteristics of PAS, is lowered.

The resin composition of the present invention may contain conventional additives within a range that does not impair the object of the invention. For example, silica as an inorganic filler, alumina, talc, mica, kaolin, clay, silica-alumina, titanium oxide, calcium carbonate, calcium silicate, calcium phosphate, calcium sulfate, magnesium carbonate, magnesium oxide, magnesium phosphate, silicon nitride, Granules such as glass, hydrotalcite, zirconium oxide,
A powdery or scale-like material or a fibrous material such as glass fiber, carbon fiber, mica ceramic fiber or the like can be blended. These inorganic fillers can be used alone or in combination of two or more. Further, these inorganic fillers may be treated with a silane coupling agent or a titanate coupling agent. From the viewpoint of melt processability, the blending ratio of the filler is preferably 30% by weight or less in the resin composition. Further, if necessary, an antioxidant, a heat stabilizer, a lubricant, a release agent, a colorant, etc. It is also possible to add the additive of.

The method of mixing the above components is not particularly limited. A generally widely used method, for example, a method of mixing each component with a mixer such as a Henschel mixer can be used.

The resin composition of the present invention is usually melt-kneaded by an extruder and pelletized, and then, for example, injection-molded or compression-molded to be molded into a desired shape.

The resin composition of the present invention can be used for various sliding parts such as bushings, bearings, sleeves, slip rings, guide rails, switch parts, gears and cams.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0030]

EXAMPLES In the examples, the dynamic friction coefficient and the wear amount are J
It was measured according to IS 7218. As a material for friction, iron (S45C) and a copolymer polyacetal (DURACON, trademark, manufactured by Polyplastics Co., Ltd.) were used. Outer diameter 25.6 mm, inner diameter 20.0 mm, length 1
It was processed into a 5.0 mm hollow cylinder, and the contact surface with the PPS sample was treated with 800 emery sandpaper. PP
The S sample was a square plate having a length of 30 mm, a width of 30 mm, and a thickness of 3 mm. These were set in a friction wear tester Model EFM-III-E manufactured by Orientec Co., Ltd., and the dynamic friction coefficient was measured by performing a test for 33 minutes at a surface pressure of 12.5 kg / cm ² and a linear velocity of 20 cm / sec. The amount of wear was measured by measuring the weight change of the mating material and the PPS sample before and after the test, and indicated by the weight change per 10 km running from the running distance during the test.

The melting degree V ₆ was 320 ° C. and the load was 20 kgf using a flow tester CFT-500A manufactured by Shimadzu Corporation.
Viscosity (poise) measured after holding for 6 minutes at L / D = 10 / cm ² .

[0032]

Polymerization Example 1 523.1 kg of flaky sodium sulfide (60.8% by weight Na ₂ S) was placed in a 4 m ³ autoclave.
Then, 1200 kg of N-methyl-2-pyrrolidone (hereinafter sometimes abbreviated as NMP) was charged. With stirring under a nitrogen stream, the temperature was raised to 204 ° C., and 126.3 kg of water was distilled off. Then, seal the autoclave 180
After cooling to ℃, p-dichlorobenzene (hereinafter p-D
597.2 kg and NMP40
I charged 0 kg. 1 at a liquid temperature of 150 ° C using nitrogen gas
The temperature was started by pressurizing to kg / cm ² G. Liquid temperature 220
While stirring at 3 ° C. for 3 hours, a cooling medium of 20 ° C. was flowed around the coil wound around the upper part of the autoclave to cool it. After that, the temperature was raised, the liquid temperature was stirred at 260 ° C. for 3 hours, the temperature was then lowered, and the cooling of the upper part of the autoclave was stopped. During cooling of the upper part of the autoclave, the liquid temperature was kept constant so as not to drop. The maximum pressure during the reaction is 8.81 kg / cm ² G
Met.

The resulting slurry was repeatedly filtered and washed with warm water by a conventional method, and dried at 130 ° C. for about 4 hours in a hot air circulation dryer to obtain white powdery PAS. The obtained PAS
The melt viscosity V ₆ of (P-1) was 960 poise.

[0034]

Polymerization Example 2 524.8 kg of flaky sodium sulfide (60.6 wt% Na ₂ S) was placed in a 4 m ³ autoclave.
Then, 1200 kg of NMP was charged. The temperature was raised to 204 ° C. with stirring under a nitrogen stream to distill 125.4 kg of water. Then, the autoclave was sealed and cooled to 180 ° C., and 596.0 kg of p-DCB and NMP400.
I charged kg. 1k with nitrogen gas at a liquid temperature of 150 ℃
Pressurization to g / cm ² G was started to raise the temperature. Liquid temperature 220 ℃
From that point, water was sprinkled with a water sprinkler attached outside the upper part of the autoclave to cool the upper part of the autoclave. Thereafter, the temperature was raised to bring the liquid temperature to 260 ° C., and then the mixture was stirred at that temperature for 2 hours. Next, the temperature was lowered and the cooling of the upper part of the autoclave was stopped. During cooling of the upper part of the autoclave, the liquid temperature was kept constant so as not to drop. The maximum pressure during the reaction was 8.74 kg / cm ² G.

The obtained slurry is filtered by a conventional method,
Washing with warm water was performed twice. Resin product obtained (about 50% by weight of water
2400 kg of water and 4.0 kg of acetic acid are added to
The mixture was stirred at 50 ° C for 30 minutes. The pH after stirring was 4.6. The resin was filtered off, 2400 kg of water was added, the mixture was stirred for 30 minutes and then filtered, which was repeated 5 times.

It was dried in a hot air circulation dryer at 130 ° C. for about 4 hours to obtain PAS in the form of white powder. The obtained PAS (P
The melt viscosity V ₆ of -2) was 820 poise.

[0037]

[Comparative Polymerization Example] 523.1 kg of flaky sodium sulfide (60.8 wt% Na ₂ S) and 1200 kg of NMP were charged into a 4 m ³ autoclave. The temperature was raised to 204 ° C. with stirring under a nitrogen stream, and 124.3 kg of water was distilled off. Then, the autoclave was closed and cooled to 180 ° C., and 614.4 kg of p-DCB and 400 kg of NMP were charged. 1 kg / c at a liquid temperature of 150 ° C using nitrogen gas
Pressurization to m ² G was started to raise the temperature. When the liquid temperature reached 255 ° C, the temperature was stopped and the mixture was stirred for 2 hours. Next, the temperature was lowered to 200 ° C. over 1.5 hours. Maximum pressure during reaction is 1
It was 0.31 kg / cm ² G.

The obtained slurry was repeatedly filtered and washed with warm water by a conventional method and dried at 130 ° C. for about 4 hours in a hot air circulation dryer to obtain a white powdery PAS. The obtained PAS
The melt viscosity V ₆ of (P-C1) was 315 poise.

[0039]

Examples 1 to 5 and Comparative Examples 1 to 5 With respect to 100 parts by weight of PAS obtained as described above, the amounts (parts by weight) of potassium titanate whiskers (average fiber diameter 1.0 μm) shown in Table 1 were obtained. , Average fiber length 10 μm, aspect ratio 10,
Tibrex, trademark, manufactured by Kawatetsu Mining Co., Ltd.),
Then, the mixture was melt-kneaded at a temperature of 320 ° C. using a 25 mmφ twin-screw extruder to prepare pellets. From the obtained pellets, an injection molding machine with a cylinder temperature of 320 ° C and a mold temperature of 130 ° C was used to make a flat plate having a length of 80 mm, a width of 80 mm, and a thickness of 3 mm. The coefficient and the amount of wear were measured.

The above results are shown in Table 1.

[0041]

[Table 1] In Example 1, 40 parts by weight of (B) potassium titanate whiskers were added to the resin composition of the present invention. The coefficient of dynamic friction was low and the amount of wear was small with respect to both iron and Duracon. In Example 2, (B) is 70
Example 3 is 100 parts by weight of (B).
It is a mixture of parts by weight. When the compounding amount of (B) was increased, both the dynamic friction coefficient and the wear amount were slightly increased, but the effects of the present invention could be sufficiently achieved. Examples 4 and 5
In each case, PPS treated with acetic acid was used, and the compounding amount of (B) was changed within the range of the present invention. In all cases, low dynamic friction coefficient and wear amount were exhibited.

On the other hand, in Comparative Example 1, the compounding amount of (B) in Example 1 was lowered to outside the range of the present invention. The dynamic coefficient of friction deteriorated, and the amount of wear increased significantly. In Comparative Example 2, the acetic acid-treated PPS used in Examples 4 and 5 was used, and the compounding amount of (B) was outside the range of the present invention. As compared with Examples 4 and 5, the dynamic friction coefficient was deteriorated and the wear amount was significantly increased. In Comparative Examples 3 to 5, PPS produced without cooling the gas phase portion of the reaction can was used, and the compounding amount of (B) was changed within the range of the present invention. As compared with Examples 1 to 3 in which cooling was performed, all comparative examples had a high dynamic friction coefficient and a high wear amount.

[0043]

EFFECTS OF THE INVENTION The present invention provides a PAS resin composition which can be used for sliding parts such as gears and has excellent sliding characteristics such as abrasion resistance.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kanichi Kido 3-1, Chidoricho, Kawasaki-ku, Kawasaki-shi, Kanagawa Tonen Kagaku Co., Ltd. Technology Development Center

Claims (3)

[Claims] 1. A gas phase in a reaction can by reacting an alkali metal sulfide with a dihaloaromatic compound in an organic amide solvent (A) and cooling a gas phase part of the reaction can during the reaction. A resin composition containing 100 parts by weight of polyarylene sulfide produced by condensing a part of the product and refluxing it in a liquid phase, and 10 to 200 parts by weight of (B) potassium titanate whiskers. 2. The (B) potassium titanate whiskers,
The resin composition according to claim 1, which is contained in an amount of 40 to 100 parts by weight. 3. A polyarylene sulfide (A) is added to an acid solution having a concentration of 0.01 to 5.0% by weight to obtain 100
The acid treatment is carried out at a temperature of ℃ or below.
The resin composition described.