JP2000210932A - Method for granulation of polyarylene sulfide resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To pelletize stably neat polymer of polyarylene sulfide by using a hot cutting method. SOLUTION: In this granulation method, melted polyarylene sulfide resin is extruded into cooling water at 40 to 95 deg.C water temperature from a die nozzle at 280 to 350 deg.C die temperature by an extruding machine, and simultaneously cut at an outlet of the die nozzle to be pelletized or extruded into the air from the die nozzle. Simultaneously, it is cut at the outlet of the die nozzle, and cooled thereafter in water at 5 to 95 deg.C water temperature or the air at 10 to 150 deg.C the air temperature to be pelletized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for granulating a polyarylene sulfide resin, and more particularly to a method for pelletizing a single component of a polyarylene sulfide resin.

[0002]

2. Description of the Related Art Conventionally, polyarylene sulfide-based resins have a low degree of polymerization and are too fluid to be easily molded, and therefore have been used as compounds obtained by compounding glass fibers and other inorganic fillers. Was. That is, since a powdered polyarylene sulfide-based resin has been used for compounding, so-called pelletization (go stone shape, cylindrical shape, spherical shape) has not been studied.

[0003] However, there has been a demand for pelletization of a single component of a polyarylene sulfide resin in addition to a simple compounding device, and it has been necessary to study a granulation method, but there has been no study in the past.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a granulation method for pelletizing a polyarylene sulfide resin.

[0005]

Means for Solving the Problems The present inventor has proposed that the strand cold cut method, which is a granulation method widely used for pelletizing a compound in which polyarylene sulfide resin is filled with glass fiber or the like, is a resin alone component. Although it was difficult to form pellets, it was found that the intended target could be achieved by using the hot cut method, and the present invention described below was completed.

That is, the present invention provides the following. (1) A polyarylene sulfide-based resin melted by an extruder is extruded from a die nozzle at a die temperature of 280 to 350 ° C. into cooling water at a water temperature of 40 to 95 ° C., and is simultaneously cut at an outlet of the die nozzle to be pelletized. Granulation method. (2) The polyarylene sulfide-based resin melted by the extruder is extruded into the air from a die nozzle at a die temperature of 280 to 350 ° C., and simultaneously cut at an outlet of the die nozzle. 150
A granulation method characterized by cooling with air at ℃ and pelletizing.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Polyarylene sulfide resin] The polyarylene sulfide resin used in the present invention is represented by the structural formula [-Ar-S-] (where Ar is an arylene group and S is sulfur). 7 repeating units
A polymer containing 0 mol% or more is represented by the following structural formula (I)

[0008]

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(Wherein R ¹ is selected from an alkyl group having 6 or less carbon atoms, an alkoxy group, a phenyl group, a carboxylic acid or a metal salt thereof, an amino group, a nitro group, and a halogen atom such as fluorine, chlorine and bromine. M is 0
-4. N represents the average degree of polymerization, and
The range is about 200. ) Is a polyarylene sulfide having 70 mol% or more of the repeating unit represented by the formula (1). If the content of the repeating unit is less than 70 mol%, the original crystalline component characteristic of a crystalline polymer is small, and the mechanical strength may be insufficient.

Further, a copolymer may be used in addition to a homopolymer. As the copolymerization structural unit, a metaphenylene sulfide unit, an orthophenylene sulfide unit, a pp′-diphenylene ketone sulfide unit,
-P'-diphenylene sulfone sulfide, pp'-
Examples include a biphenylene sulfide unit, a pp'-diphenylene methylene sulfide unit, a pp'-diphenylene cumenyl sulfide unit, and a naphthyl sulfide unit.

The molecular structure may be any of a linear structure, a branched structure and a crosslinked structure. That is, as the polyarylene sulfide-based resin of the present invention, in addition to a polymer having a substantially linear structure, a branched structure or a cross-linked structure obtained by polymerizing using a small amount of a monomer having three or more functional groups as a part of the monomer Can also be used. Further, it may be blended with the above-mentioned polymer having a substantially linear structure and used.

Further, as the polyarylene sulfide-based resin used in the present invention, a polymer obtained by increasing the melt viscosity by oxidative crosslinking or thermal crosslinking of a polymer having a substantially linear structure having a relatively low molecular weight and improving the moldability is also used. be able to. The polyarylene sulfide-based resin used in the present invention can be produced by a known method. For example, it can be obtained by subjecting a dihalo aromatic compound and a sulfur source to a polycondensation reaction in an organic polar solvent, washing and drying.

The polyarylene sulfide resin used in the present invention has an intrinsic viscosity η _ihr [dl / g] of 0.05 to 0.45.
dl / g, preferably 0.1 to 0.4 dl / g, more preferably 0.12 to 0.35 dl / g. Intrinsic viscosity η _ihr [dl / g]
Is larger than 0.45 dl / g, the fluidity at the time of extrusion molding is reduced, and granulation may be difficult. Also, 0.05
If it is less than dl / g, it may be easily welded even in the underwater hot cut method, and granulation may be difficult.

Further, the method of measuring the intrinsic viscosity η _ihr [dl / g] is as follows.
0.04 g ± 0.001 g of the sample was dissolved in 10 cc of α-chloronaphthalene at 235 ° C. for 15 minutes,
The relative viscosity between the viscosity obtained in a constant temperature bath at 06 ° C. and the viscosity of α-chloronaphthalene in which the polymer was not dissolved was measured, and the intrinsic viscosity η _ihr is represented by the following equation. η _ihr = ln (relative viscosity) / polymer concentration [dl / g]

[Granulation method] The polyarylene sulfide-based resin to be subjected to the granulation method of the present invention does not have sufficient viscosity even after plasticization and is brittle, so that it is difficult to form ordinary strands. A granulation method called a hot cutting method for immediately cutting the molten resin extruded from the die is adopted.

The first method of the present invention is an underwater hot cutting method, and the second method is an aerial hot cutting method. In any of the methods, the shape of the obtained pellets is sufficiently varied, such as a stone-like shape, a cylindrical shape, a spherical shape, and the like, and the quality of the pellets is also good, with few abnormally shaped articles and beads. As an additional effect of using cooling water, residual alkali metal salts in polyarylene sulfide resin (sodium chloride, lithium chloride, etc.)
Is preferred because it can be removed.

[In-water hot cutting method] This is the first invention of the present invention, which is a granulation method of cutting a molten resin in water and pelletizing it. The main apparatus to which the granulation method of the present invention is applied is composed of an extruder, a die, an underwater cutting device, a filter, and a dryer. The die is a horizontal type in which a cutter shaft is arranged in a horizontal direction, or a die. Any of the vertical type in which the cutter shaft is arranged vertically in a horizontal direction and upward may be used.

The granulation method of the present invention is characterized in that a polyarylene sulfide resin melted by an extruder is heated to a die temperature of 280-3.
50 ° C, preferably 290 to 340 ° C, more preferably 300 to 320 ° C, and a water temperature of 40 to 95 ° C from the dice nozzle.
The granulation method is characterized by extruding into cooling water at the same time, and simultaneously cutting and pelletizing at the exit of the die nozzle.

If the die temperature is 280 ° C. or lower, granulation is difficult. If the die temperature is 350 ° C. or higher, partial decomposition of the resin starts, causing burns and other problems. Furthermore, if the temperature of the cooling water is 40 ° C. or lower, vacuum bubbles are likely to be generated in the resin, and an extra load is imposed on the heating of the die, which is inappropriate. If the temperature of the cooling water is 95 ° C. or higher, the cooling of the pellets is insufficient and it is difficult to prevent the fusion of the pellets.

The granulation method of the present invention is characterized in that the molten resin is cut in water, and good quality pellets can be obtained without welding. However, the dies in water are used to prevent clogging from rapid cooling. It is necessary to provide a heating jacket for keeping the area around the die nozzle warm. It is important not only to ensure continuous productivity but also to guarantee a smooth startup. Also, steam, oil and the like are suitable for the heat source. Furthermore, since cutting is performed on the surface of the die, the rotary cutter blade is constantly in contact with the die, and the die and the cutter blade are made of a wear-resistant special alloy such as tungsten carbide or titanium carbide. In addition, the nozzle structure of the die may be a circumferential nozzle or a horizontal nozzle,
Since there is little welding between the pellets cut in water, there is generally an advantage in that the interval between nozzles can be reduced. Further, either a center cut method provided at the center of the die or a side cut method adjacent to the die may be used depending on the position where the cutter is mounted. In any case, in order to stabilize the shape and dimensions of the pellet,
It is important to control the operation of appropriately adjusting the gap between the die and the cutter blade according to the properties of the polyarylene sulfide resin.

The cut pellets are transferred to a filter together with water by a circulating pump, and then subjected to a centrifugal separator, a hot air circulating drier, or the like for dehydration and drying. According to the underwater hot-cut method of the present invention, as described above, it is possible to expect an ancillary effect capable of removing residual alkali metal salts (sodium chloride, lithium chloride, and the like) in the polyarylene sulfide-based resin,
The degree of the effect depends on the die temperature (ie, resin temperature).
The higher the cooling water temperature and the smaller the size of the pellet, the larger the temperature.

[Air Hot-Cut Method] This is a granulation method according to the second invention of the present invention, in which a molten resin is cut in air and pelletized. The main device to which the granulation method of the present invention is applied is composed of an extruder, a die, an aerial cutting device, and a dryer, and the die is a horizontal type in which a cutter shaft is arranged in a horizontal direction, or the die is horizontally downward. Any of the vertical type in which the cutter shaft is arranged in the vertical direction may be used. The aerial cutting device is provided with a cooling device using water or air, and cools the pellets cut in the air with circulating cooling water or air blown from a blower. As mentioned above,
The water-cooling method is preferable because the residual alkali metal salt (sodium chloride, lithium chloride, etc.) in the polyarylene sulfide-based resin can be removed as an effect accompanying the granulation.

In the granulation method of the present invention, a polyarylene sulfide-based resin melted by an extruder is fed to a die temperature of 280-3.
Extruding from a die nozzle into air at 50C, preferably 290-340C, more preferably 300-320C,
At the same time, the granulation method is characterized in that cutting is performed at the exit of a die nozzle, and thereafter, the resultant is cooled with water having a water temperature of 5 to 95 ° C. or air having a temperature of 10 to 150 ° C. to be pelletized.

If the die temperature is 280 ° C. or lower, granulation is difficult. If the die temperature is 350 ° C. or higher, the melt viscosity of the resin is too low, and welding at the time of cutting tends to occur. Furthermore, when using cooling water, the cooling water temperature must be 5 ° C.
If the temperature is below, the temperature is too low for cooling the resin, and vacuum bubbles are easily generated, which is inappropriate. Cooling water temperature is 95 ℃
Above this, the cooling of the pellets is insufficient and it is difficult to stabilize the quality such as fusion of the pellets. Similarly, in the case of air cooling, the upper limit value and lower limit value of the temperature have the same critical meaning.

The granulation method of the present invention is characterized in that the molten resin is cut in the air, and has advantages such as low cutting noise, little chips, and easy start-up. However, problems such as the cut pellets being blown and being fused together easily occur.For this reason, for example, cooling water is sprayed on the wall surface of the aerial cutting device around the die to form a water film and fly. It is important to cool the pellets after cutting, such as immediately cooling the pellets.

Depending on the position of the die and the cutter blade, either a center cut system in which a rotary cutter blade shaft is provided at the center of the die or a side cut system in which a rotary cutter blade shaft is provided near the die may be used. In any case, since the molten resin is cut, defective products such as renju pellets are likely to occur, and in order to stabilize the quality of the pellet shape and dimensions, the gap between the die and the cutter blade must be precisely Need to be adjusted.

The cut pellets are transferred to a centrifugal separator together with running water and dehydrated and dried, or the cut pellets are transferred to a belt-type transfer device and cooled by blowing air blown from a blower, It is taken out by an ejector, transported by air as it is for cooling, and enters the final product packaging process. In addition, if water is used for cooling in the air hot-cut method of the present invention, an additional effect of removing residual alkali metal salts (such as sodium chloride and lithium chloride) in the polyarylene sulfide resin can be expected as described above. .

[0028]

[Example 1]

(Preparation of resin) Lithium sulfide 50 in a 50-liter polymerization tank
Mol (2297 g), p-dichlorobenzene 50 mol (7350 g), lithium hydroxide-hydrate 2.5 mol (105 g), water 25 mol (450 g) and NMP21
One liter was added and reacted at 260 ° C. for 3 hours. 100
After cooling to ℃, the liquid phase was separated to obtain a precipitated polymer.
The obtained polymer was washed twice with cold water. The polymer was placed again in a 50-liter polymerization tank, 25 liters of NMP and 150 cc of acetic acid were added, and the mixture was washed at 150 ° C. for 1 hour. After cooling, the solid polymer was washed once with cold water. After washing 1
The film was dried with a flash dryer at 20 ° C. for 24 hours, and further vacuum-dried at 120 ° C. for 24 hours. The obtained polymer was a linear type polyphenylene sulfide resin having an intrinsic viscosity η _ihr [dl / g] of 0.23 dl / g, and the amount of residual lithium in the polymer was 100 ppm.

(Granulation) The polyphenylene sulfide resin powder obtained by polymerization, washing and drying by the above-mentioned ordinary production method is used to cut the polyphenylene sulfide resin powder into an underwater cutting device shown in FIGS. 1 and 2 [Extruder (Nippon Steel Works, Ltd.) TEX44XCT-38.5B
W-4V), and supplied to an underwater cutting device (horizontal cutter direct drive underwater cutting device manufactured by Nippon Steel Works Co., Ltd.), and pelletized by operating at a die temperature of 300 ° C. and a circulating water temperature of 80 ° C. The shape of the pellet thus obtained was a stone-like shape, the size was 3 mm in diameter and 1 mm, and the operation time was 10 hours in a row, and stable pellet production was possible.
In addition, the incidence of defective products such as odd-shaped products and renju products in product pellets was 3% on average as a result of five random samplings during the operation time.
Met. The amount of residual lithium in the obtained pellet was 40 ppm.

Example 2 In Example 1, the granulating apparatus was replaced with an aerial hot-cut apparatus (extruder (TEX44XCT-38.5BW-4V manufactured by Nippon Steel Works, Ltd.) shown in FIG.
In place of the aerial hot cut device (Aerial center hot cut device CHC-1 manufactured by Nippon Steel Works Co., Ltd.)], the die was extruded into air at 300 ° C., and simultaneously cut at the die nozzle outlet. The same operation was performed except that the mixture was cooled with water and pelletized. The operation time was 10 hours continuous, and stable pellet production was achieved. The average occurrence rate of defective products such as irregularly shaped products and renju products in product pellets was 3% as a result of five random samplings during the operation time. The amount of residual lithium in the obtained pellet was 65 ppm.

[0031]

According to the granulation method of the present invention, a neat polymer of polyarylene sulfide can be pelletized stably, and the amount of residual lithium in the obtained pellet can be reduced by using water for cooling. Therefore, favorable effects on physical properties can be expected.

[0032]

[Brief description of the drawings]

FIG. 1 is an underwater hot cut granulation apparatus used in an embodiment of the present invention (overall view).

FIG. 2 is an underwater hot-cut granulator used in an embodiment of the present invention (enlarged view of a main part).

FIG. 3 is an aerial center hot cut granulation apparatus used in an embodiment of the present invention.

[Explanation of symbols]

 1: Motor 2: Speed reducer 3: Polyarylene sulfide resin 4: Extruder 5: Underwater cutting device 6: Screen filter 7: Centrifuge 8: Hot water tank 9: Extruder 10: Die head 11: Dice 12: Rotation Blade 13: Hot water inlet 14: Hot water & pellet outlet 15: Cutter housing 16: Handle 17: Coupling 18: Motor 20: Screen changer 21: Dice holder 22: Dice 23: Rotating blade 24: Cutter housing 25: Cutter unit 26: Motor 27: trolley

Claims (2)

[Claims] 1. Extruding a polyarylene sulfide resin melted by an extruder at a die temperature of 280 to 350 ° C. from a die nozzle into cooling water at a water temperature of 40 to 95 ° C., and simultaneously cutting and pelletizing at a die nozzle outlet. Characterized granulation method. 2. A polyarylene sulfide resin melted by an extruder is extruded from a die nozzle into air at a die temperature of 280 to 350 ° C., and simultaneously cut at an outlet of the die nozzle. 10
A granulation method characterized by cooling with air at 150 ° C. and pelletizing.