JPH04128011A - Manufacture of polyarylene sulfide resin granulated matter - Google Patents

Abstract

PURPOSE:To manufacture easily and efficiently a PAS granulated matter whose particle density and bulk density are high, by a method wherein polyarylene sulfide resin powder is pressed into a space between press rolls by including the powder having the particle diameter within a specific range at a specific ratio or higher, compression-molded and crushed. CONSTITUTION:When dried powder of PAS powder is compressed, granulated and pulverization-treated by making use of a dry compression granulating machine under a nonmelting state, stability in a quality such as bulk denity and productivity of a granulated matter become preferable. A matter containing at least the 30wt.% PAS powder having particle diameter of less than 0.7mm is preferable as the PAS powder to be used and the granulated matter to be obtained is made so that its particle density is within a range of 0.7-1.5g/cc, bulk density is within a range of 0.4-0.8g/cc and at least the 50wt.% granulated matter possesses the particle diameter within a range of 0.7-20mm. A PAS particle material which has no problems in heat deterioration, thermal crosslinking, coloring and a viscosity change can be presented for molding using the PAS granulated matter and favorable molding is made possible.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to polyarylene sulfide resin (hereinafter referred to as PAS).
Regarding the method for obtaining granules by mechanically compressing the powder of
This invention relates to a method for obtaining granules with large particle size and specific gravity by pressing PAS powder between two press rolls and compression molding under high pressure by rotation of the rolls.

When extrusion and injection molding are performed by this method, a PAS with a high discharge rate and easy handling is obtained, and the quality and productivity of the molded product are improved.

(Prior technology) PAS is an engineering plastic with excellent heat resistance, chemical resistance, flame retardance, electrical properties, and mechanical properties, and is used as a molding material for various purposes such as electrical and electronic parts and automobile and automobile parts. It is being This resin is, for example,
Japanese Patent Publication No. 1973-1989 showed that dihalo-substituted aromatic compounds and alkali metal sulfides can be obtained by reacting them in polar organic solvents.
It is described in Publication No. 12240 and the like. According to this method, the polymerization system is generally taken out from a high temperature into a container under normal pressure or reduced pressure, and then the powdered polymer is recovered through solvent recovery and washing, so that the final particle size is 1.
A powder of 0-500 μm is obtained. This polymer has a low bulk density of around 0.3, which means that it is bulky and difficult to handle, and also has the disadvantage that air is drawn in during melt extrusion, resulting in a decrease in discharge rate and significantly poor extrusion productivity. In particular, when the powder is washed with a special solvent for the purpose of improving the purity of the polymer, the particles become even finer and a powder containing fine powder of 10 μm or less is obtained, which further reduces the above disadvantages.
In addition, the work environment is worsened due to the scattering of fine powder.

On the other hand, a method of slowly cooling the system after the polymerization reaction to recover particulate polymer having a relatively large bulk density was disclosed in Japanese Patent Application Laid-Open No. 59-153.
Although disclosed in Japanese Patent Publication No. 60-235838, etc., special conditions or strict adjustment of temperature and stirring conditions are required at the time of particle formation, that is, at the cooling stage of the polymerization system. When mass producing polymers, there is a problem in that it is difficult to control the particle size.

Conventionally, the method for producing pellets of PAS compositions is to supply the raw material mixture of the composition to a melt-kneading machine such as an extruder, heat-melt it, knead it, and form pellets, but PAS itself has a bulk density. Because of the small, fine powder, the stable supply of the raw material mixture to the melt-kneading machine was impaired, which not only resulted in a decrease in productivity but also deteriorated the shape of the resulting pellets. Furthermore, a large amount of air tends to be mixed into the fine powder of PAS, causing undesirable oxidation and deterioration in the melt-kneading machine, and also causing the resulting pellets to become less dense.

In addition, if good molded products such as films, threads, sheets, pipes, and rods cannot be obtained due to poor feedability of PAS powder during extrusion molding, etc., the powder may be melted and extruded in advance to form pellets (granulation). In some cases, this method was adopted.

However, since the pelletized material is melted during re-molding, alterations such as thermal deterioration, crosslinking, and coloring occur, making it difficult to obtain a good molded product.

In order to solve these problems, it is necessary to increase the bulk density of the PAS powder used without altering its quality.

(Problems to be Solved by the Invention) In view of the above-mentioned circumstances, the present invention provides a manufacturing method capable of obtaining PAS granules containing almost no powder and having a high bulk density.

(Means for Solving the Problems) That is, the present invention provides (1) production of polyarylene sulfide resin granules, characterized in that polyarylene sulfide resin powder is forced between press rolls, compression molded, and pulverized. method, (2) the manufacturing method of (1) using polyarylene sulfide resin powder containing 30% by weight or more of polyarylene sulfide resin powder with a particle size of less than 0.7 mm, (3) the granulated material is mechanically compressed. Therefore, the particle density is 0.
The manufacturing method of (1), which is a pulverized product of a thin plate-like solid in the range of 7 to 1.5 g/cc, (4) 50% by weight or more of the granulated material has a particle size of 0.7 mm or more, and bulk density is 0.4
g, /cc or more, (5) alkali metal ion content of polyarylene sulfide resin powder (after decomposing 500 mg of the sample by sulfuric acid addition ashing method, flame atomic absorption spectrometer The production method of (1) uses a powder with a weight fraction determined and calculated by an optical method) of toppm or less, and (6) uses a polyarylene sulfide resin powder with a THF extraction rate of 2% by weight or less. This relates to the manufacturing method of (1).

In the present invention, PAS is defined as a polymer partially or completely containing the repeating units represented by the following formulas (A) to (E), such as those disclosed in Japanese Patent Publication No. 45-3368 and Japanese Patent Publication No. 52-12240. It can be obtained by the method disclosed in the above publication.

a b c. d e f Each substituent has the following structure.

Y: -R and -○R (R is selected from Hl alkylcycloalkyl, aryl and aralkyl. However, the alkyl part has 1 to 20 carbon atoms, and the aryl part has 6 to 18 carbon atoms. ), -x (x is
Selected from F, CI, Br, 1ka)
, -CN, -C○OH, -SO. HNH2-NO3.
COOM and one SO. M (M is Li, Na,
metal cations selected from Rb, Cs).

z: -so. - -o-, -co-, -sR'
R" SO- -〇- and -Si-(R" and R
R"R" is the same as R above. ) In formula (A), a is an integer of O to 4, and in formula (B), b
and C are integers from 0 to 4, respectively, and in formula (C), d is 0
an integer of ~3, in formula (D), e and f are each O~4
and in formula (E), g represents an integer of O to 6.

Further, PAS in the present invention is represented by the above formulas (A) to (E
) may be a random copolymer, a block copolymer, a mixture thereof, or a mixture with a homopolymer. Further, the molecular weight of various PASs is not particularly limited, and includes non-crosslinked products, crosslinked products, and mixtures thereof.

Typical examples of these resins include polyphenylene sulfide, polyphenylene sulfide ketone, polyphenylene sulfide sulfone, and polyphenylene sulfide ketone sulfone. Among PAS, a structure in which the repeating units are bonded at the para position with respect to the aromatic ring is preferable in terms of heat resistance and crystallinity.

In particular, poly-p-phenylene sulfide is suitable in terms of physical properties and economic efficiency.

In the present invention, it is necessary to mechanically compress the PAS powder in an unmolten state to obtain granules. In order to obtain the granulated product, a method is used in which the powder is forced between two rotating press rolls using a screw feeder or the like, compression-molded under high pressure by the rolls, made into a solid material such as a thin plate, and then pulverized. is most preferable.

As a specific method, it is particularly preferable to compress the dry powder using a dry compression granulator, granulate it, and then pulverize it in terms of quality stability such as bulk density and productivity of the granulated product. It is. Generally, the dry compression granulator includes a feeder that supplies raw material powder to a roll section, a press roll that compresses and molds the powder, and a thin plate-like solid material compressed there that is coarsely crushed to an appropriate size and granulated. It consists of a combination of granulating machines that adjust the diameter.

First, for example, when powder is fed by a screw feeder, the range of rotation speed is not particularly limited, but is determined by the throughput of the feeder and the granulator. If the feeding rate is too low, the thickness of the solid material after compression will become thinner, and the production amount of the granulated product will decrease, which is not preferable. on the other hand,
If the feeding rate is too high, the production rate of the granules will increase, but the granules will not be compressed sufficiently between the rolls, making them brittle against external forces, that is, only particles with low particle density will be obtained, which is not preferable.

When a normal screw feeder is used, its rotational speed is preferably in the range of 50 to 20 rpm.

Next, the compression pressure of the two rolls used for compression molding is the most important factor that influences the hardness of the thin plate, that is, the particle density and bulk density of the granulated product. The compression pressure range is preferably 0.2 to 8 tons/cm, particularly preferably 1 to 4 tons/cm. This value is 0. If it is 2 to 8 tons/cm, the compression effect is large and the granules can be obtained with a high particle density, which makes it easier to maintain the shape when fed to the melt-kneading machine, and there is no solidity on the surface of the roll teeth. Since substances are difficult to adhere to, there are no variations in shape or particle density, and the quality of the granulated product is stable. Further, the range of the rotation speed of the roll is not particularly limited, but is generally preferably 5 to 40 rpm.

Further, the type of machine used for coarsely crushing and sizing the thin plate-like solid material after compression is not particularly limited, and a conventional machine may be used. However, in the method of the present invention, in order to obtain granules in which 50% by weight or more has a particle size of 0.7 mm or more and a bulk density of 0.4 g/cc or more, it is necessary to It is necessary to use a sieving machine equipped with a screen having a size ranging from 0.7 mm to 20 mm.

This eye opening is 0. If it is in the range of 7 to 20 mm, there will be less mixing of fine powder at the stage of sizing, and it will not take much time to sizing, so the productivity of the granulated product will be high, which is preferable.

In addition, the bulk density of the granulated product is suitable, it can be fed at a constant rate when fed to a melt mixer, and it is preferable because it can be mixed uniformly with other compounds. In addition, from the viewpoint of particle size distribution and bulk density, the opening size is preferably in the range of 2 to 10 mm.

The PAS powder used in the method of the present invention may have any viscosity, but preferably contains 30% by weight or more of powder with a particle size of less than 0.7 mm. The particle size is
It goes without saying that even if PAS contains 70% by weight or more of particulate matter of 0.7 mm or more, it is possible to further increase the particle density or bulk density by mechanically compressing it by the method of the present invention. On the other hand, powder less than 0.7 mm
In the case of PAS powder containing 0% by weight or more, the bulk density is usually 0.
Although it is bulky in the range of 2 to 0.4 g/cc, according to the method of the present invention, granules with high bulk density can be obtained by forced compression regardless of the bulk. Therefore, it can be said that the benefits of compression granulation are greater for materials containing finer particles.

Furthermore, as a method of reducing impurities contained in PAS, that is, alkali metal ions such as sodium ions, or low molecular weight substances extracted with tetrahydrofuran solvent, etc., high temperature treatment in an organic polar solvent such as N-methylpyrrolidone is performed. method is known. however,
According to this method, the alkali metal ion content in the resin (this is the weight fraction calculated by decomposing 500 mg of a sample by the sulfuric acid addition ashing method and then quantifying it by the flame method using a flame atomic absorption spectrometer). is less than 1100 pI), or the amount of low molecular weight substances extracted in tetrahydrofuran under reflux for 1 hour (TI (F extraction rate is the amount of low molecular weight substances in the resin extracted under refluxing of tetrahydrofuran (THF)). After holding a mixture of 5 g of sample and 75 ml of THF under reflux in a hot water bath (75°C) for 1 hour, the mixture was filtered, the solvent was distilled off from the obtained filtrate, and the remaining solid content was determined. Although a highly pure polymer with a weight percent (weight percent calculated using By applying the compression granulation method described above, it is possible to obtain granules with a high bulk density.

The granulated material obtained by the above method preferably has a particle density in the range of 0.7 to 1.5 g/cc, and preferably has a bulk density of 0.7 to 1.5 g/cc. 4~0゜8 g/cc
is within the range of Moreover, the particle size distribution is preferably such that 50% by weight or more of the granulated material has a particle size in the range of 0.7 to 20 mm. The maximum throughput of the dry compression granulator used in the method of the present invention varies depending on its mechanical scale, but is usually in the range of 10 to 5000 kg/hr. Since it has a processing capacity that sufficiently exceeds the feeding rate to the melt kneader in the next step, it does not reduce the productivity of the melt extrusion step.

According to the present invention, films, threads,
It is possible to provide a PAS granular material that is free from problems of thermal deterioration, thermal crosslinking, coloration, and viscosity change even when molded into pipes, rods, sheets, etc., and can be molded favorably.

(Example) Next, the present invention will be specifically explained using Examples, but the present invention is not limited thereto.

Example 1 As a raw material powder, 6 with a particle size of 0.07 mm was used as 2
Polyphenylene sulfide (PP) consisting of 71% by weight of 9% by weight and 71% by weight of 0.07 mm or more and less than 0.7 mm.
As S), a commercial product Rydon ■-1 (manufactured by Phillips Petroleum) was used. This resin has a melt viscosity of 45
The bulk density in powder form was 0.37 g/cc.

The melt viscosity was measured at 310° using a Koka type flow tester.
This is a value measured at a C1 shear rate of 10''sec-'.The bulk density was calculated by filling a 100cc cylindrical container with a sample using a powder tester.

The particle size distribution was determined by measuring the weight fraction of each fraction using a powder tester for 100 g of the sample by dividing it through a normal sieve. Further, the particle density of the granulated product obtained after compression and sizing was calculated by a conventional liquid displacement method using immersion in water.

A commercially available dry compression granulator roller compactor (RCP-20O3° manufactured by Kurimoto Iron Works Co., Ltd.) was used as an apparatus for compression molding the powder.

First, 20 kg of PPS powder was charged into a hopper with a screw feeder, the rotation speed of the screw feeder was set to 1100 rpm, the roll compression pressure was set to 1.7 tons/cm, and the o-
15 rpm.

After adjusting the screen spacing of the sieving machine to 4.9 mm, operation was started. Shortly thereafter, the powder supplied from the top was compressed, crushed, and sized, and collected as granules in a tray at the bottom. After about 1 minute, a product with a constant thickness and shape was stably obtained, and at that point, the production rate of the granules was measured to be 80 kg/hr. As shown in Table 1, the properties of this granulated material are as follows: the particle density is 1.08
g/cc.

The bulk density is 0.58 g/cc, and the particle size is 0.7 mm.
The above ゛ is 99% by weight, and 93% by weight is
The particles ranged from 2.0 mm to 5 mm. At the same time, there was no fine powder with a particle diameter of less than 0.07 mm, and the product was easy to handle without scattering of fine powder. The granules were extruded using a 65 mm single-screw extruder (L/D=30, full-flight screw with a compression ratio of 3.5) at a temperature of 3.
As a result of melt-kneading and pelletizing under extrusion conditions of 30° C. and screw rotation speed of 1100 rp, the granules were extremely well-incorporated, and the production rate of pellets 7) was as high as 85 kg/hr, with no fluctuation in discharge.

Comparative Example 1 Granulation was attempted in the same manner as in Example 1 except that the O-L compression pressure was adjusted to 61 tons/cm. The results were as shown in Table 1. Due to insufficient compression between the rolls, a plate-like solid material could not be obtained, and most of the material recovered through the sieving machine remained in powder form. This thing has a bulk density of 0
．． 47g/cc.

Less than 0.07mm 26% by weight and 0.07 or more 0.7
The particle size distribution was less than 76% by weight.

When this was melted and kneaded in the same manner as in Example 1, the pellet production rate was as low as 17 kg/hr due to severe air entrainment into the mixer and poor biting.Moreover, the color of the discharge strand was the same as in Example 1. It was worse than in the case of

Example 2 Instead of PPS commercial product Lyun V-1, linear PP
Rydon PR-06, a commercially available product made by cross-linking and thickening S by heat treatment (manufactured by Fisi-Sips Petroleum)
Granulation was carried out in the same manner as in Example 1 except that .

This resin powder has a melt viscosity of 1020 poise, a bulk density of 0.39 g/cC, 21% by weight of particles with a particle size of less than 0.07 mm, and 79% by weight of particles with a particle size of Q, Q7 mm or more and less than 0.7 mm. It was included. The results obtained were as shown in Table 1. Examples 3 to 6 14.7 N-methylpyrrolidone was added to a 50 L autoclave.
kg and 35.0 mol of sodium sulfide hexahydrate were charged, the temperature was raised to 200°C under a nitrogen atmosphere, 750 mL of water was distilled off, and 35.0 mol of P-dichlorobenzene and N-methyl were added. Add 3.5 kg of pyrrolidone, 240
The reaction was carried out at ℃ for 5 hours. After the reaction, the flash slurry was collected in a container maintained at 240° C. and under reduced pressure.

The solvent was distilled off from this slurry, the remaining solid was washed three times with hot water, and the cake was dried at 120°C to obtain powdered PPS. This polymer has a melt viscosity of 120 poise, a bulk density of 0.35 g/cc, 28% by weight of particles with a particle size of less than 0.07 mm, and 722% of particles with a particle size of 0.07 mm or more and less than 0.7 mm. It was a powdered polymer containing heavy pills. Using this powder, compression molding was performed under the granulation conditions shown in Table 1, and the properties of the granules were measured.

The results were as shown in Table 1.

Example 7 Powdered PPS containing some particulate matter was obtained in the same manner as in Example 3 except that 35.0 moles of sodium benzoate were added together with 35.0 moles of sodium sulfide in the method of Example 3. The melt viscosity of this polymer is 4200 poise,
In addition, the bulk density is 0.41 g/cc and the particle size of 11 is 0.07.
mm undropped 11% by weight, 0.07 mm or more 0.7
It contained 89% by weight of particles smaller than mm. Using this, compression molding was performed under the granulation conditions shown in Table 1. The results were as shown in Table 1.

Comparative Example 2 In the method of Example 7, the temperature was further raised to 260°C without flash removal at 240°C after the reaction, and 3.6 kg of water was charged into the system at that temperature for 30 minutes. After stirring at 3 times the stirring speed of
．． The mixture was slowly cooled at a rate of 8°C/min and held at 235°C for 30 minutes, and then the reaction vessel was rapidly cooled to collect the slurry. Granular PPS was obtained in the same manner as in Example 7 except for this operation. However, this polymer has a particle size of 0.07 mm or more.
．． 32% by weight is less than 7mm, and 0.7mm or more2
．． 59% by weight of particles less than 0 mm, which is more effective in granulation than normal 7-row extraction, but 0.07 mm
It contained as much as 9% by weight of fine powder, and the granulation effect was smaller than that of a granulation method using mechanical compression, and there was still no improvement in handling.

Example 8 N-methylpyrrolidone 9.9k in a 50L autoclave
g, 25.0 mol of sodium sulfide hexahydrate, 10 g of sodium hydroxide, and 25.0 mol of bis(P-chlorophenyl)sulfone, and heated at 200° under a nitrogen atmosphere.
After raising the temperature to C and reacting at that temperature for 4 hours, the reaction vessel was cooled and the contents were taken out. Part of this content10.
4 kg and 22.4 kg of the slurry immediately after the PPS reaction obtained in the same manner as in Example 3 were mixed, sealed after nitrogen purging, heated to 210° C., and reacted at this temperature for 3 hours. After cooling the reaction vessel, the contents were filtered and the solid content was boiled and washed three times with hot water, and the cake was dried at 120°C to obtain a powdery polymer. This polymer was a block copolymer consisting of PPS and polyphenylene sulfide sulfone, and its melt viscosity was 1800 poise. Bulk density is 0
．． At 25 g/cc, the powdered polymer contained 54% by weight of particles with a particle size of less than 0.07 mm and 46% by weight of particles with a particle size of 0.07 mm or more and less than 0.7 mm.

Using this, compression molding was performed under the granulation conditions shown in Table 1. The results were as shown in Table 1.

Example 9 Using an autoclave, 5 kg of PPS powder Lyon V-1 used in Example 1 and 30 kg of N-methylpyrrolidone were added.
The mixture was heated to 220'C under a nitrogen atmosphere and held at that temperature for 1 hour, after which the system was cooled and the contents were filtered and washed three times with water. 120 pieces of the resulting cake
It was dried at °C for 5 hours to obtain a powdered polymer. This polymer has a sodium ion content of 80 ppm, a THF extraction rate of 0.18% by weight, and a bulk density of 0.15 g/c.
It was c. Using this, compression molding was performed under the granulation conditions shown in Table 1. The results were as shown in Table 1.

/ (Effects of the invention) According to the method of the present invention, PAS which is bulky and difficult to handle can be
PAS granules containing no fine powder and having high particle density and bulk density can be easily and efficiently produced from powder. When the granulated material obtained by this method is extruded or injection molded in a melt kneader, it is easy to handle and the extrusion speed can be improved.

teenager Reason Man

Claims (1)

[Claims] 1. A method for producing polyarylene sulfide resin granules, which comprises pressing polyarylene sulfide resin powder between press rolls, compression molding, and then pulverizing. 2. The method for producing resin granules according to claim 1, wherein the polyarylene sulfide resin powder contains 30% by weight or more of particles having a particle size of less than 0.7 mm. 3. The granules have a particle density of 0.7 to 0.7 by mechanical compression.
The method for producing resin granules according to claim 1, which is a pulverized product of a thin plate-like solid material in a range of 1.5 g/cc. 4. The method for producing resin granules according to claim 1, wherein 50% by weight or more of the granules have a particle diameter of 0.7 mm or more and a bulk density of 0.4 g/cc or more. 5. The alkali metal ion content of the polyarylene sulfide resin powder (weight fraction calculated by decomposing 500 mg of a sample by the sulfuric acid addition ashing method and then quantifying it by the flame method using a flame atomic absorption spectrometer) is 100 ppm or less. The method for producing a resin granule according to claim 1, characterized in that a powder is used. 6. The method for producing a resin granule according to claim 1, characterized in that the polyarylene sulfide resin powder has a THF extraction rate of 2% by weight or less.