JPS6219453B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyphenylene sulfide extrusion molding material that has made it possible to extrude polyphenylene sulfide, which was previously considered impossible. The present invention relates to a molding material used for extrusion molding of polyphenylene sulfide from which molded products with excellent performance can be obtained. Polyphenylene sulfide has the general formula

It is a polymer represented by the formula and is usually abbreviated as PPS. This PPS has the properties of both a thermoplastic resin and a thermosetting resin, and not only can it be heated and melted to form the same molding as a thermoplastic resin, but it can also be heat-crosslinked and is used as a thermosetting material for baking paints, etc. It can also be used as a resin. PPS molded products have excellent properties as an engineering plastic, including excellent chemical resistance, good retention of mechanical properties over a wide temperature range, and hardness at high temperatures. PPS is currently manufactured only by Philips Petroleum in the world and is sold under the trade name "Ryton." Although various methods for producing PPS are known, the PPS currently on the market is said to be produced by reacting P-dichlorobenzene and sodium disulfide in a polar solvent. The commercially available PPS molding material is V-1, which is an uncrosslinked product.
grade, crosslinked products P-2, P-3, P-4
grade (crosslinking degree is P-2<P-3<P-4),
and R-6 grade, which is a pellet-like crosslinked product (all of the previous four products are in powder form). In addition, R-4 grade pellets containing glass fibers and products containing fillers, lubricants, and other additives are commercially available depending on the purpose. V-1 is mainly used for slurry/spray coating and impregnation, P-2 is for fluidized bed coating, P-3 is for powder coating, P-4 is for compression molding, and R-6 is mainly for injection molding. used, but not limited to. Crosslinking of PPS is carried out by heating uncrosslinked PPS in the presence of oxygen, usually in air. The crosslinking temperature is below 288℃, which is the melting temperature of uncrosslinked PPS.
It is usually carried out at a temperature of around 250°C. When heated, chain extension occurs at the same time as crosslinking, increasing the viscosity when melted, ultimately resulting in an insoluble and infusible resin. However, when the required degree of crosslinking is reached, it is usually cooled to form a moldable powder or moldable powder. It is said to be in pellet form. Previously, it was said that extrusion molding of PPS was impossible. There is no grade for extrusion molding among the commercially available PPS grades. The main reason why extrusion molding of PPS is impossible is due to changes in the viscosity of PPS during molding. In other words, when commercially available partially cross-linked PPS is melted and extruded in an extruder, the viscosity of the molten PPS rapidly increases, and the increase in viscosity is irregular, making it difficult to extrude a constant amount of PPS. It becomes possible. When the viscosity increases, the amount of extrusion under constant extrusion pressure decreases, and in some cases, extrusion becomes impossible. There is also a method of increasing extrusion pressure as the viscosity increases.
It is difficult to use because the increase in viscosity is irregular, and furthermore, the rate of increase in viscosity is so large that it has been impossible to follow the extrusion pressure with a conventional extrusion molding machine. Therefore, even if it is possible to extrude conventional PPS using an extrusion molding machine, it is impossible to obtain a molded product with the required shape due to large changes in the extrusion rate.For example, even if a sheet is molded, its thickness There were many cases in which the extrusion amount became 0 and the product was cut due to the drastic change in the thickness. The second reason why extrusion is not possible is that PPS has a very low melt viscosity. One way to increase the melt viscosity is to increase the degree of crosslinking, but as the degree of crosslinking increases, the rate of change in the viscosity increases, and PPS with a small viscosity change and high viscosity has not been known. The third reason is gas generation when PPS is melted. The cause of this is not very clear, but this low molecular weight PPS is caused by the presence of low molecular weight PPS as a by-product during polymerization, and by the partial scission of PPS molecular chains during crosslinking to produce low molecular weight PPS. It is expected that the main cause of this is the volatilization and decomposition of molecular weight PPS. The components of the gas are mainly organic, with small amounts of sulfur compounds such as SO ₂ also found. This generated gas remains in the PPS molded product, deteriorating its mechanical and electrical properties, and may even cause corrosion of the mold material. In particular, when manufacturing films and thin sheets by extrusion molding, there is a high possibility that depressions or holes will form on the surface due to this gas generation, and this problem must also be resolved in order to make extrusion molding possible. it is conceivable that. The purpose of the present invention is to obtain an extrudable PPS molding material, and in particular, an improved PPS extrusion molding material that causes less crosslinking reaction during heating and melting during extrusion molding, and therefore has less viscosity change. The purpose is to obtain. Furthermore, the present invention aims to obtain a partially crosslinked PPS extrusion molding material that has a relatively high viscosity and little change in viscosity in that state, and furthermore, to obtain a PPS extrusion molding material that generates little gas during molding. The purpose is to Another object of the present invention is to obtain an extrusion molded product with superior mechanical properties and electrical properties compared to molded products conventionally obtained by methods other than extrusion molding. As a result of various research studies aimed at achieving these objectives, the inventors of the present invention have determined that the viscosity can be increased by heat-treating partially crosslinked PPS to a temperature of 290°C or higher in an atmosphere substantially free of oxygen. little change
It has been found that not only can PPS be obtained and gas generation is reduced, but also that PPS with a relatively high viscosity of any desired viscosity can be obtained by adjusting the heat treatment conditions. The present invention
It is a PPS extrusion molding material that contains PPS alone or this treated PPS as a main component or as at least one component. That is, in the present invention, the polyphenylene sulfide in the polyphenylene sulfide extrusion molding material is formed by partially crosslinked polyphenylene sulfide in an atmosphere substantially free of oxygen.
This is a polyphenylene sulfide extrusion molding material characterized in that it is a treated polyphenylene sulfide obtained by heat treatment at a temperature of 0.degree. C. or higher. The extrusion molding material of the present invention exhibits extremely small change in viscosity during heating and melting, allowing for stable extrusion molding and producing good molded products with little gas generation. Moreover, an extrusion molding material having an arbitrary viscosity can be obtained depending on the processing conditions. The reason why the heat treatment under anoxic conditions in the present invention makes the change in viscosity due to the crosslinking reaction during heating and melting extremely small and reduces gas generation is not sufficiently clear. However, if there is a compelling reason, one of the reasons seems to be that the crosslinking reaction is terminated by heating to a high temperature in an oxygen-free atmosphere. That is, it is presumed that thermal crosslinking of PPS in the presence of oxygen progresses by first forming active sites in PPS that are likely to cause crosslinking, and then those active sites causing crosslinking. When PPS is heated under substantially oxygen-free conditions, crosslinking occurs through the active sites already present, but no new active sites appear to form.
Therefore, for example, when partially cross-linked PPS is heated in a substantially oxygen-free condition, cross-linking of the PPS proceeds due to the active sites already present and the viscosity of PPS increases, but the active sites are gradually exhausted and no more crosslinking will no longer occur, and no increase in viscosity will occur. As a result of the active sites being exhausted, new crosslinking is less likely to occur, resulting in less viscosity change. Such a mechanism can well explain the results such as the viscosity change of PPS shown in FIG. 1 and Reference Examples to Examples. . According to the present invention, partially cross-linked PPS can be produced without newly generating active sites by heating in an oxygen-free atmosphere.
It is presumed that the crosslinking reaction of the active sites present therein can be terminated, and a stable material can be obtained in which the crosslinking reaction does not proceed during subsequent heat molding. Therefore, by the treatment of the present invention, it is possible to control the viscosity during melt molding, and it is also possible to significantly reduce the change (increase) in viscosity during melt molding. Also, the reason for the decrease in gas generation is the cause of the gas generated (low molecular weight PPS etc.)
This seems to be due to the fact that they are removed in advance. In fact, a weight loss of PPS is observed in this treatment. An atmosphere substantially free of oxygen means an atmosphere in an inert gas such as nitrogen or under reduced pressure. In particular, in order to remove generated gases, it is preferable to perform the reaction under reduced pressure. Of course, even in an inert gas atmosphere, the gas is sufficiently diffused because the temperature is high. However, reduced pressure is more effective in extracting gas that remains mixed in PPS. In the case of processing under reduced pressure, it is also preferable to replace air etc. with an inert gas such as nitrogen in advance and then reduce the pressure. In the case of reduced pressure, the degree of pressure reduction is not particularly limited as long as oxygen is not substantially present, but when reducing pressure from an atmosphere where air is present, the pressure is 50
mmHg or less, particularly 10 mmHg or less is preferable, and it is preferable to perform the treatment under vacuum if possible.
When expressing this substantially oxygen-free atmosphere in terms of oxygen partial pressure, the oxygen partial pressure under reduced pressure or in an inert gas atmosphere is preferably 2 mmHg or less. When the oxygen partial pressure is below 2 mmHg, crosslinking due to trace amounts of oxygen is so small as to be completely ignored, and it is considered that crosslinking due to oxygen does not substantially occur. Partially crosslinked PPS is PPS that is crosslinked by heating uncrosslinked PPS in an oxygen atmosphere. For example, grades such as P-2, P-3, P-4, and R-6 are examples thereof, and fillers such as R-4 grade may also be blended. However, in order to reduce the complexity of the process and reduce costs, it is preferable to carry out the process according to the present invention following the process of crosslinking uncrosslinked PPS. In this case, appropriate crosslinking can be performed in the first stage of the treatment in the present invention, and as will be described later, the first stage crosslinking treatment also has an influence on the treatment in the present invention. In addition, uncrosslinked PPS is heated to 290℃ or higher in an oxygen-free atmosphere, and a small amount of oxygen is added to crosslink PPS. The treatment of the present invention can also be achieved by further continuing heating. The processing temperature in the present invention is higher than the melting temperature of PPS, that is, higher than about 290°C. Normally, above this temperature, partially crosslinked PPS is in a highly viscous liquid state. Since crosslinking of PPS has traditionally been carried out at temperatures below its melting point, PPS is in powder form in the processed state. Since PPS is in a liquid state, the treatment in the present invention can be carried out not only in a stationary state but also in a fluidized state such as under stirring. Furthermore, in consideration of shortening processing time, etc., the temperature is preferably 310°C or higher. The upper limit of the temperature is not limited as long as PPS does not decompose in a large amount, but preferably 500°C or less is appropriate. Although the heating time under anoxic conditions in the present invention is not particularly limited, it is preferable to heat until the rate of increase in viscosity decreases. That is, as shown in specific examples below, PPS with a higher degree of crosslinking exhibits a higher rate of increase in viscosity when heated under anoxic conditions, and this rate of increase in viscosity gradually decreases after a certain period of time. Therefore, it is preferable to carry out heating until a decrease in the rate of increase in viscosity is observed. Furthermore, when the heat treatment temperature is increased, it takes a shorter time for the viscosity increase rate to be observed to decrease. Of course, the heat treatment in the present invention may not need to be continued until a decrease in the rate of increase in viscosity is observed. This is because the heating and melting time during extrusion molding is relatively short, so slight changes in viscosity can often be ignored. For example, depending on the degree of PPS crosslinking, a treatment time of 10 minutes or more is appropriate for treatment at 330°C under vacuum, and a treatment time of 30 seconds or more for treatment at 400°C. Since the heat treatment in the present invention removes low molecular weight compounds that cause gas generation, the degree of weight loss of the PPS extrusion molding material of the present invention is reduced even if it is subsequently heated. Any degree of reduction in weight loss will give good results, but in order to be clearly effective in practical use, for example, in the case of PPS only (i.e., without a filler) at a temperature of 300°C and under reduced pressure (several It is desirable to perform the heat treatment according to the present invention so that the weight loss is 0.3% by weight or less, preferably 0.1% by weight or less when heated for 120 minutes at a temperature (mmHg). In contrast, commercially available partially crosslinked
PPS exhibits a weight loss of about 0.5-2% by weight upon heating under the same conditions. The length of time for heat treatment of uncrosslinked PPS in the presence of oxygen, that is, the degree of crosslinking of PPS, affects the physical properties of the PPS molding material obtained by heat treatment in the present invention.
One of them is the heat-treated PPS in the present invention.
is the apparent viscosity of For example, as a specific example, the longer the uncrosslinked PPS is treated at 240°C in air, the higher the rate of increase in apparent viscosity when heat-treated at 330°C under vacuum, and the higher the apparent viscosity. Viscosity is reached. However, when the time of the heat treatment under vacuum exceeds a certain period of time, the rate of increase in apparent viscosity decreases. FIG. 1 is a graph showing the relationship between the treatment time and the change in apparent viscosity at a load of 20 kg/cm ² when partially crosslinked PPS is heat treated at 330° C. under vacuum (several mmHg). A is for uncrosslinked PPS, B is for crosslinked PPS that was crosslinked in air at 240°C for 30 minutes,
Similarly, C is treated at 240℃ for 60 minutes, and D is treated at 240℃ for 120 minutes.
In the case of 240 minutes at 240° C., E indicates 240 minutes, and it can be seen that the longer the crosslinking treatment time, the higher the apparent viscosity. Similarly, it can be seen that the apparent viscosity is influenced by the crosslinking treatment temperature and the treatment temperature and treatment time in the present invention, and the higher the treatment temperature or the longer the treatment time, the higher the apparent viscosity. Furthermore, from the apparent viscosity, the treated material of the present invention
Considering the preferred embodiment of PPS, 330℃, load 20
The apparent viscosity at Kg/ ^cm2 is more than 500 poise, especially
1000 poise or more is appropriate. Of course, as shown in Figure 1, PPS with a low degree of crosslinking or uncrosslinked PPS
In this case, you can also use 200 to 500 poise. In this case, it is suitable for molding materials whose viscosity is increased by components other than PPS, such as extrusion molding materials containing large amounts of fillers, and low-viscosity PPS, which is difficult to extrude with PPS alone, is suitable for this purpose. used in cases. The treated object after the heat treatment in the above-mentioned present invention
PPS is usually cooled and then powdered. This treated PPS powder can be used as an extrusion molding material as it is, or it can be made into pellets by pelletizing the powder or by directly pelletizing the treated PPS without powdering it. Furthermore, the extruded material can be in a form other than powder or pellet form. Furthermore, the extrusion molding material of the present invention can be used not only as a treated PPS alone, but also as a mixture with untreated PPS. The extrusion molding material of the present invention may also contain various additives in addition to the PPS to be treated. Typical additives are glass fiber, carbon fiber, asbestos,
Other fibrous reinforcing fillers include calcium carbonate, quartz powder, micro glass spheres, milled glass fibers, graphite, and other powdered inorganic fillers. In particular, glass fiber is often used as a reinforcing filler. These fillers can be added to the PPS to be treated in relatively large amounts, typically up to about 80% by weight of the molding material. In addition to reinforcing fillers and inorganic fillers, various additives can be used, such as lubricants such as fluororesins, molybdenum compounds or antimony compounds, and synthetic resins such as polyimide. The content of components other than the above-mentioned PPS to be treated in the extrusion molding material of the present invention is not particularly limited, but is usually preferably 80% by weight or less,
The lower limit is not limited. Furthermore, as mentioned above,
The heat treatment for making PPS anoxic in the present invention may be performed in the presence of these additives. For example, commercially available glass fiber-containing partially crosslinked PPS pellets (R-
4 grade) can be treated at a temperature of 290° C. or higher in an atmosphere substantially free of oxygen to form the extrusion molding material of the present invention. The extrusion conditions or the type of extrusion molding machine are not particularly limited. In addition to the usual general extrusion molding machine, special extrusion such as electric wire coating extrusion is also possible. Conventionally, in order to produce pellet-like PPS molding materials, PPS alone or with the addition of fillers and the like has been extruded into pellets. However, this is for the purpose of kneading and granulation, and is not for the purpose of obtaining molded products. Therefore, pelletizing is not required to have a strict shape, and in fact filler-containing pellets can only be formed into irregularly shaped granules that are incomparable to ordinary thermoplastic resin pellets. Extrusion molding of the extrusion molding material of the present invention is a molding method whose purpose is to obtain a final molded product such as a rod, pipe, sheet, etc. with defined dimensional accuracy. Of course, if a pellet-shaped extrusion material is required as a type of extrusion material, pelletization by conventional extrusion may be carried out. The type of molded product obtained by extrusion molding the extrusion molding material of the present invention is not particularly limited. For example, a bar,
There are angles, channels, sheets, films, pipes, wire coverings, etc. Many of these molded products are technically difficult or cost-effective to obtain by methods other than conventional extrusion molding. By extrusion molding the extrusion molding material of the present invention, these molded products can be easily obtained to the extent that it is not much different from extrusion molding of ordinary synthetic resins. Furthermore, the extrusion molding material of the present invention not only enables extrusion molding, but also has the characteristic of generating less gas. This will solve the problem of deterioration in the mechanical strength and electrical properties of molded products caused by residual PPS particles and improve the performance of PPS molded products themselves. Molded products obtained from the extrusion molding material of the present invention can be widely used not only in fields where the characteristics of PPS can be exhibited, such as electrical parts, electronic parts, corrosion-resistant equipment, heat-resistant equipment, and mechanical parts, but also in various other industrial fields. . The present invention will be specifically explained below using reference examples and examples (including comparative examples), but the present invention is not limited only to these examples. Reference example 1 Commercially available partially crosslinked PPS powder (P-4 grade)
[All grades shown below are PPS commercially available under the trade name "Ryton" manufactured by Phillips Petroleum.] Partially cross-linked pellets (R-6 grade) were each heated under vacuum (several mmHg).
[Hereinafter, "under vacuum" refers to conditions in which PPS in an air atmosphere is reduced in pressure to several mmHg unless otherwise specified]. After heating at 330°C for 15 minutes to melt, it was cooled to room temperature and solidified. , a solid PPS without bubbles inside was obtained. For comparison, commercially available PPS, P
When untreated grade products of -4 and R-6 were heated in air at 300°C for 15 minutes, only solid PPS with many bubbles inside due to gas generation was obtained. Reference Example 2 Approximately 2 g of a sample (treated product, P-4 treated product, R-4 treated product) that had been heat-treated under reduced pressure by the same method as Reference Example 1 was weighed into a porcelain crucible, and the sample was heated under reduced pressure (several mm).
Hg), and the weight loss was measured after heating at 300°C for 120 minutes. The results are shown in Table 1 below. For comparison, the weight loss of commercially available grades (both P-4 and R-6 were untreated) was measured under the same conditions, and the results are also shown in the same table.

[Table] Reference Example 3 Commercially available uncrosslinked PPS powder (V-1 grade) was crosslinked by heating at 240°C in an air stream for 60 minutes, and then heat-treated at 330°C for 120 minutes under vacuum. This sample was cooled, crushed, and tested using a Koka flow tester.
The apparent viscosity was measured at 300° C. and a load of 20 kg/cm ² and found to be 650 poise. Approximately 10g of the same sample was placed in a porcelain crucible and placed in an air stream.
After heating at 330° C. for 30 minutes, the apparent viscosity was measured again under the above conditions, and it was 750 poise, indicating that there was little increase in viscosity. On the other hand, the apparent viscosity of commercially available partially crosslinked PPS powder (P-3 grade) was measured under the above conditions and was 720.
It was poise. Approximately 10 g of this commercially available P-3 grade powder was placed in a porcelain crucible, and the powder was placed in an air stream for 330 g.
When the apparent viscosity was measured after heating at ℃ for 30 minutes, it was 4000 poise, indicating that the viscosity had increased significantly. Reference Example 4 Due to the treatment according to the present invention, viscosity change is small.
It is shown that PPS molding materials with various apparent viscosities can be obtained. Commercially available uncrosslinked PPS powder (V-1 grade) was crosslinked under the heating conditions shown in Table 2, and then subjected to vacuum heat treatment under the same conditions shown in Table 2. The obtained PPS was pulverized and heated at 330° C. for 30 minutes in an air stream in the same manner as in Reference Example 3. The results of measuring the apparent viscosity after vacuum heat treatment and the apparent viscosity (change) after further heating in an air stream are shown in Table 2 (measurement conditions are the same as Reference Example 3).
Partially crosslinked PPS without treatment according to the present invention for comparison
The viscosity (change) when heated in an air stream is also shown in the same table.

[Table] Example 1 Commercially available uncrosslinked PPS powder (V-1 grade) was crosslinked by heating it in air at 260°C for 120 minutes and then crosslinked under vacuum.
Heat treatment was performed at 330°C for 120 minutes. This sample was cooled to room temperature and ground into small pieces using a speed mill (manufactured by Akira Tekko Co., Ltd.). Next, insert this sample into a screw with a screw diameter of 20 mm.
Injected into a mmφ single screw extruder, cylinder temperature and die temperature approximately 320℃, screw rotation speed 30 per minute.
A film with a thickness of 60 microns and a width of 15 cm was produced by extrusion by rotation. The obtained film was dark brown and translucent, had no air bubbles, and did not break even when bent. For comparison, commercially available partially crosslinked PPS pellets (R
-6 grade) was extruded under the same conditions, but many small holes were formed in the film due to the gas generated by PPS, and there was also a significant fluctuation in the extrusion rate. Furthermore, the film of this comparative example had poor flexibility and was easily broken when bent. Example 2 Commercially available uncrosslinked PPS powder (V-1 grade) was crosslinked at 240°C in an air stream for 60 minutes and then heated at 360°C under vacuum.
The mixture was heat-treated for 40 minutes. This sample was cooled and pulverized, and glass fiber chopped strands (CS-03- manufactured by Asahi Fiberglass Co., Ltd., manufactured by Asahi Fiberglass Co., Ltd.)
MA-497) and quartz powder (Fuseurex E-1 manufactured by Tatsumori Co., Ltd.) were added to form pellets using an extruder.
On the other hand, for comparison, commercially available PPS powder (P-4 grade)
was used untreated and made into pellets with the same formulation as in this example. These pellet-shaped molding materials were put into a single-screw extruder with a screw diameter of 40 mmφ, and extruded at a cylinder temperature and die temperature of approximately 320°C, a screw rotation speed of 20 to 30 revolutions per minute, and an extrusion pressure of 60 kg/cm ² .
A rod-shaped molded product with a diameter of 20 mm was obtained. When the pellets of this example were used, a uniform rod-shaped molded product with a smooth surface and no bubbles inside was obtained. This molded product could not be easily destroyed even by hitting it with a mallet. On the other hand, molded products using comparative pellets had many voids inside, and due to fluctuations in the extrusion rate,
Uneven seam-like areas were formed every 20 to 30 cm. This extrusion molded product (length approximately 1 m) was dropped from a height of 1 m onto a concrete floor and broke into 4 to 5 pieces. Example 3 A commercially available uncrosslinked PPS powder (V-1 grade) was crosslinked at 260°C in an air stream for 120 minutes and then dried under vacuum for 330°C.
Heat treatment was performed at ℃ for 120 minutes. This sample was cooled and crushed, and chopped glass fiber strands (manufactured by Asahi Fiberglass Co., Ltd., CS-03-MA-497) were added to the sample so that the glass fiber content was 30% by weight. Made into pellets. The pellets were put into a single-screw extruder with a screw diameter of 40 mmφ, and a sheet with a thickness of 2 mm and a width of 15 cm was extruded at a cylinder temperature and a die temperature of approximately 320°C, a screw rotation speed of 20 to 30 revolutions per minute, and an extrusion pressure of 60 kg/cm ^2. A shaped article was molded.
The obtained sheet had a smooth surface and was dense with no air bubbles on the surface or inside. Various test pieces were cut out from this sheet and their physical properties were measured. The results are shown in Table 3. For comparison, chopped glass fiber strands were added to commercially available partially crosslinked PPS powder (P-4 grade) so that the glass fiber content was 30% by weight, and pellets were formed using an extruder, and the pellets were made into pellets in the same manner as in this example. It was extruded under the following conditions. In the case of this comparative example, many voids were generated in the sheet due to the gas generated from PPS, the sheet surface was rough, and the sheet was non-uniform due to the extreme fluctuation in the extrusion amount. In order to compare the physical properties of molded products, samples for physical property measurement were molded by compression molding. Commercially available PPS powder (P-
4 grade) was used to make pellets with the same glass fiber content of 30% by weight as in this comparative example, and the pellets were heated in an air stream at 330°C for 60 minutes to further crosslink, and then heated to 300°C for flat plate molding. It was placed in a mold and heated and pressurized for 10 minutes at a pressure of 100 kg/cm ² . Next, this was cooled to room temperature while being pressurized, and the thickness was 2 mm.
A flat molded product measuring 20 cm in length and 20 cm in width was obtained. Various test piece samples were cut out from this molded product and their physical properties were measured. The results are summarized in Table 3.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the crosslinking temperature and heating time under vacuum and the change in apparent viscosity at 300° C. and a load of 20 kg/cm ² . The lines A, B, C, D, and E, which connect the measurement points, indicate the crosslinking treatment time in air at 240°C for 0 minutes, 30 minutes, and 60 minutes, respectively.
Indicates minutes, 120 minutes, and 240 minutes.

Claims (1)

[Claims] 1. The polyphenylene sulfide in the polyphenylene sulfide extrusion molding material is partially crosslinked polyphenylene sulfide, and the temperature is 290°C or higher in an atmosphere substantially free of oxygen. A polyphenylene sulfide extrusion molding material, characterized in that it is a treated polyphenylene sulfide obtained by heat treatment. 2. The extrusion molded material according to claim 1, wherein the atmosphere substantially free of oxygen is a reduced pressure atmosphere. 3. The extrusion molding material according to claim 1, wherein the substantially oxygen-free atmosphere is a reduced pressure atmosphere or an inert gas atmosphere with an oxygen partial pressure of 2 mmHg or less. 4. The extrusion molding material according to claim 1, wherein the heat treatment temperature is 310 to 500°C. 5. A patent claim characterized in that the partially crosslinked polyphenylene sulfide is a polyphenylene sulfide obtained by heat treating uncrosslinked polyphenylene sulfide below its melting temperature in the presence of oxygen. Extruded material in range 1. 6 Temperature of polyphenylene sulfide to be treated
The extrusion molding material according to claim 1, wherein the extrusion molding material has a weight loss of 0.3% by weight or less when heated at 300° C. for 120 minutes under reduced pressure.