JPH0514603B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention efficiently recovers a solvent from a viscous solution of an elastomeric polymer such as an olefinic elastomeric polymer or a halogenated elastomeric polymer, and directly determines the volatile content. The invention relates to a method for separating granular elastic polymers with low granularity.

[Conventional technology]

Conventionally, the following methods are known as methods for separating and recovering elastic polymers such as olefin-based elastic polymers, halogenated polyolefins, and chlorosulfonated polyolefins from organic solvent solutions.

[1] A method of insolubilizing and precipitating and recovering a solution of the elastic polymer in an organic solvent by introducing it into a poor solvent for the elastic polymer [poor solvent precipitation method].

[2] A method of recovering the solvent from a solution of the elastic polymer in an organic solvent by steam distillation, recovering the elastic polymer in a dispersed state in water, and further drying [steam distillation method].

[3] A method in which a solution of the elastic polymer in an organic solvent is supplied to the surface of a heated rotating drum, the solvent is removed, and the film is taken out as a dry film [rotating drum drying method].

[4] A method of supplying an organic solvent solution of the elastic polymer to a vented extrusion dryer and drying it [vented extrusion dryer method].

Among these methods, the poor solvent precipitation method requires a large amount of poor solvent, requires extra heat to recover the poor solvent and the organic solvent from the mixed solvent after precipitation, and has the disadvantage that the process is complicated. However, the steam distillation method requires the addition of various dispersants to prevent agglomeration of the dispersed elastic polymer, which has the disadvantage that the physical properties such as heat resistance and aging resistance of the elastic polymer deteriorate as a result. However, the rotary drum drying method has the disadvantage that it is difficult to process the resulting thin film, and the vented extrusion dryer method has the disadvantage that even if a solution with a low concentration of elastomer is supplied, the elastomeric polymer with a low volatile component content is It is difficult to obtain coalescence, and strong heating is required to completely remove it.
The drawback is that the resulting elastic polymer deteriorates.

Furthermore, recently, a method using a centrifugal thin film evaporator is known for concentrating solutions of organic solvents such as wax, polypropylene, polystyrene, and polybutadiene. However, even with this method, the polymer concentration is too high for elastic polymers with low heat resistance stability such as halogenated polyolefins and chlorosulfonated polyolefins.
It is best to concentrate it to 70% by weight, and if it is concentrated more than that, the elastic polymer often suffers thermal deterioration and causes operational problems such as adhesion to the inside of the equipment or clogging. . For example, according to a proposal in JP-A No. 57-47303, as a method for separating and drying a chlorosulfonated polyolefin from a carbon tetrachloride solution, the solution is fed to a stirring thin film evaporator to increase the polymer concentration. A method has been proposed in which the concentrate is concentrated to 30 to 70% by weight and the concentrate is supplied to an extrusion dryer equipped with a vent for drying. As is clear from the description in the publication, if the polymer concentration exceeds 70% by weight during concentration in a thin-film evaporator, the elastic polymer will burn and adhere to the inside of the device, resulting in clogging and other operational problems. It was recognized that it was not possible to obtain dry elastic polymers in one step using only the thin film evaporator.

Conventionally, as a method for obtaining granular elastic polymers from elastic polymer solutions, the solvent is once separated and dried using the method described above, the elastic polymer is extruded under melting conditions, and then granulated by cutting. method has been adopted. Furthermore, in this method, the heat generated during cutting causes the particles of the elastic polymer to re-fuse, so cutting is performed in water when granulating the elastic polymer. As described above, granulation of elastic polymers requires complicated processing steps such as a separation drying step and an underwater cutting granulation step.

[Problem that the invention seeks to solve]

In view of the above-mentioned state of the art of recovering particulate elastic polymers from solutions of elastic polymers in organic solvents, the present inventors have devised a method for recovering particulate elastic polymers from elastic polymer solutions through easy processing. As a result of studying a method for producing a polymer, it was found that the above object could be achieved by supplying the elastic polymer solution to a centrifugal thin film evaporator and performing a solvent removal treatment under specific conditions, and the present invention was achieved. According to the method of the invention,
Even solutions of elastic polymers with low heat stability, such as halogenated polyolefins and chlorosulfonated polyolefins, can be treated in one step without causing thermal deterioration, and without causing adhesion or clogging inside the equipment. It has the advantage that an elastic polymer with a uniform particle size can be obtained directly, and it also does not require the complicated cutting and granulation process in water unlike the conventional method. Furthermore, although it was recognized from the description in the above-mentioned known literature that an elastic polymer with a low content of volatile components cannot be obtained directly by a thin film evaporator, the method of the present invention It is unique in that a particulate elastic polymer can be obtained by feeding it into an apparatus and operating it under specific conditions.

[Summary of the invention]

To summarize the present invention, the present invention provides an organic solvent solution of an elastic polymer having a Mooney viscosity (ML100°C 1+4) of 10 or more, wherein the concentration of the elastic polymer is 5.
0.2 to 50% by weight and a viscosity of 500,000 centipoise or less to a centrifugal thin film evaporator, and 0.2 to 50% by weight per 1 kg/hr of elastic polymer contained in the supplied solution.
An elastomeric polymer characterized by applying 1.4kw of real power and applying centrifugal force to the solution to form a thin film while removing the solvent until the content of volatile components reaches a range of 10% by weight or less. The gist of the invention is a granulation method.

[Means and actions for solving problems]

The elastic polymer used in the method of the present invention is an elastic polymer having a Mooney viscosity (ML100°C 1+4) of 10 or more, preferably an elastic polymer having a Mooney viscosity (ML100°C 1+4) of 30 to 100. It is a polymer. Examples of the elastic polymer include olefin-based elastic polymers, halogenated olefin-based elastic polymers, and chlorosulfonated polyolefin-based elastic polymers. The olefin-based elastic polymer is a low-crystalline or amorphous olefin-based polymer with a crystallinity of usually 20% or less, and specifically, ethylene/propylene/5-ethylidene-2-norbornene copolymer, ethylene·
Propylene/dicyclopentadiene copolymer, ethylene/propylene/1,4-hexadiene copolymer, ethylene/1-butene/5-ethylidene-
2-norbornene copolymer, ethylene/1-butene/dicyclopentadiene copolymer, ethylene/
1-butene/hexadiene copolymer, ethylene/
Examples include propylene copolymer and ethylene/1-butene copolymer. As a halogenated olefin-based elastomeric polymer, the crystallinity is usually 20.
% or less of low crystallinity or non-crystalline halogenated olefin-based elastic polymers, specifically chlorinated polyethylene, chlorinated polypropylene, and chlorinated products of each of the above-mentioned olefin-based elastic polymers,
The halogen content of the halogenated olefin-based elastic polymer is usually 15 to 50% by weight, preferably 30% by weight.
and 40% by weight. As a chlorosulfonated polyolefin elastomer, the crystallinity is low.
A chlorosulfonated polyolefin-based elastic polymer with a low crystallinity or non-crystalline content of 20% or less, specifically, a chlorosulfonated polyolefin corresponding to the above-mentioned chlorinated polyolefin or the chlorinated product of each olefin-based elastic polymer. An example of this is an elastomeric polymer. The chlorosulfonated polyolefin-based elastomeric polymer is produced by reacting chlorine and sulfur dioxide gas or chlorine with sulfuryl chloride in the solution of the olefin-based elastomer, or by reacting chlorine and sulfur dioxide gas or chlorine with the solution of the chlorinated olefin-based elastomer. It can be produced by reacting sulfuryl chloride. The chlorine content of the chlorosulfonated polyolefin elastomer is usually in the range of 25 to 45% by weight, and the sulfur content is usually in the range of 25 to 45% by weight.
It ranges from 0.5 to 1.5% by weight. The Mooney viscosity (ML100°C 1+4) of the elastic polymer used in the method of the present invention is usually 10 to 150, preferably
It ranges from 30 to 100.

In the method of the invention, the elastic polymer is used as a solution in an organic solvent. The concentration of the elastomeric polymer in the solution needs to be in the range of 5 to 50% by weight, more preferably 10 to 20% by weight.
is within the range of If the concentration of the elastic polymer in the solution is too low, the amount of solvent to be evaporated will increase, which is unfavorable from an industrial perspective.If the concentration of the elastic polymer is too high, the viscosity of the solution will increase and it will no longer be a liquid. The viscosity of the organic solvent solution of the elastic polymer that cannot be handled is 500,000
It needs to be within a centipoise range, more preferably from 500 to 100,000 centipoise, particularly preferably from 1,000 to 50,000 centipoise. If the viscosity of the solution becomes too high, it can no longer be handled as a liquid and pumping becomes difficult, which is undesirable from an industrial standpoint.

Various organic solvents can be used as the organic solvent constituting the solution. Specifically, aliphatic hydrocarbons such as pentane, methylpentane, hexane, and heptane, alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, and cyclohexane, aromatic hydrocarbons such as benzene, toluene, and xylene, and chloride. Examples include halogenated hydrocarbons such as methylene, chloroform, bromoform, carbon tetrachloride, ethylene chloride, trichloroethane, trichloroethylene, tetrachloroethane, and chlorobenzene.

In the method of the present invention, an elastic polymer solution is supplied to a centrifugal thin film evaporator and subjected to solvent removal treatment. As the centrifugal thin film evaporator, any type of device can be used, such as a horizontal centrifugal thin film evaporator or a vertical centrifugal thin film evaporator.
In each type of centrifugal thin-film evaporator, a rotor with rotary blades or rotary movable blades is provided inside the heat transfer shell, and a rotor with rotary blades or rotary movable blades is provided on the outside of the heat transfer shell, which usually heats the heat transfer shell. Therefore, a jacket for heat medium circulation is provided.

In the method of the present invention, removing the solvent from the elastic polymer solution supplied to the thin film evaporator,
The content of volatile components is 10% by weight or less, preferably
In order to obtain a granular elastic polymer of 3.0% by weight or less, the elastic polymer 1 contained in the supplied solution must be
Range of 0.2 to 1.4kw per Kg/hr, preferably
It is necessary to apply a substantial power in the range of 0.4 to 0.8 kw to the solution and apply centrifugal force to the solution to form a thin film. If the actual power per 1 kg/hr of the elastic polymer contained in the solution is less than 0.2 kw, a granulated elastic polymer cannot be obtained, and if it is greater than 1.4 kw, a granulated elastic polymer can be obtained. , the thermal deterioration becomes large and it becomes impossible to obtain a particulate elastic polymer of excellent quality.
Here, the actual power is the power (W) required for steady operation of the centrifugal thin film evaporator under the supply of the elastic polymer solution, to This is the value obtained by subtracting the power (W) required to run the thin film evaporator dry.

In the method of the present invention, the desolvation treatment using the centrifugal thin film evaporator is usually carried out at a temperature of 50 to 200°C, preferably 80 to 150°C, and the pressure at that time is usually normal pressure to reduced pressure. . If the elastic polymer is susceptible to thermal deterioration, the solvent may be removed under reduced pressure if necessary. The pressure at that time is usually 760 to 10 mmHg, preferably 760 to 200
It is in the mmHg range. In the solvent removal treatment using the centrifugal thin film evaporator of the present invention, the length from the raw material supply port of the heat transfer cylinder of the device is usually 10 to 30% of the total length.
This region is the solvent removal region, and usually 90 to 70% of the region is the granulation region. In this desolvation region, the supplied elastic polymer is desolvated by centrifugal stirring and heat is supplied from the heat transfer surface, causing centrifugal stirring and kneading, and it is estimated that most of the actual supplied power is consumed. In the granulation region, the elastic polymer is repeatedly broken and fused to produce granules with a uniform particle size, and it is presumed that almost no real supply power is consumed in this region.

The average particle size of the granular elastic polymer obtained by the method of the present invention is usually 0.1 to 5 mm, preferably 2.0 mm.
It is in the range of mm. Further, the content of volatile components in the granular elastic polymer is 10% by weight or less, preferably 3% by weight or less.
The range is below % by weight.

〔Example〕

The method of the present invention will be specifically explained using examples.

Example 1 A rotating cylindrical heat transfer cylinder (inner diameter 150 mm, length 420 mm) with a jacket for heat medium circulation equipped with a raw material supply port, a solvent evaporation vapor discharge port, and a granular elastic polymer discharge port was installed via a mechanical seal. Horizontal centrifugal thin film evaporator equipped with a rotor with rotating blades (rotational speed
The idling power at 1050 rpm was 1.5 kW), and a heating medium was circulated through the jacket to maintain the temperature at 100°C.

The raw material elastic polymer solution was a carbon tetrachloride solution of chlorinated ethylene/1-butene/5-ethylidene-2-norbornene (ENB) copolymer with a chlorine content of 25.5% by weight and a Mooney viscosity (ML100°C 1+4) of 83. A viscosity of 5000 centipoise at 50°C and a polymer concentration of 12.6% by weight were used.

The carbon tetrachloride solution of the chlorinated ethylene/1-butene/ENB copolymer was supplied to the horizontal centrifugal thin film evaporator at a rate of 16 kg/hr at 50°C, and the rotor was heated at 1050 r.pm under atmospheric pressure. rotate at a speed of
The horizontal centrifugal thin film evaporator was operated continuously.
At this time, 13.9 kg/hr of carbon tetrachloride (recovery rate 99.4%) was recovered by condensing the steam discharged from the steam outlet of the horizontal centrifugal thin film evaporator,
Granular chlorinated ethylene is discharged from the granular elastic polymer outlet.
A 1-butene/ENB copolymer was obtained. The diameter of the particulate chlorinated ethylene/1-butene/ENB copolymer was in the range of 0.5 to 2 mm, did not contain any particulate elastic polymer, and had a volatile content of 3.75% by weight. Further, the granular elastic polymer had a good hue, the insoluble content in toluene at the boiling point temperature was 1% by weight or less, and no gel-like polymer was observed to be formed due to thermal deterioration.

In addition, the required operating power at this time is 4kw, the actual required power is 2.5kw, and the elastic polymer is 1Kg/hr.
The actual power per unit was 1.25kw.

Example 2 Using the same equipment as Example 1, 133 jackets were
It was kept at ℃.

The raw material elastic polymer solution was a carbon tetrachloride solution (50°C) of chlorinated ethylene/propylene copolymer (ethylene/propylene molar ratio 81/19) with a chlorine content of 22.9% by weight and a Mooney viscosity (ML100°C 1+4) of 121.
Viscosity at 3000 centipoise, concentration 10% by weight)
It was used. This raw material liquid was supplied to the apparatus at a rate of 22.8 kg/hr at 25° C., and continuous operation was performed by rotating the rotor at a speed of 1050 rpm under atmospheric pressure conditions. At this time, the steam discharged from the steam outlet was condensed to recover 18.1 kg/hr of carbon tetrachloride, and a granular chlorinated ethylene-propylene copolymer was obtained from the granular elastic polymer outlet. The granular product ranged from 0.5 to 2 mm, was free of fines, and had a volatile content of 5.0% by weight. Furthermore, the granular product had a good hue, the amount of insoluble matter in toluene at the boiling point temperature was 1% by weight or less, and no gel-like polymer was formed due to thermal deterioration. In addition, the required operating power at this time is 2.4kw, and the actual required power after subtracting the idling power of 1.68kw is 0.72kw, and the elastic polymer 1Kg/hr
The actual power per unit was 0.3kw.

Comparative Example 1 The same equipment as in Example 1 was used, but the jacket temperature was maintained at 133°C. The raw material elastic polymer solution has a chlorine content of 15.8% by weight and a Mooney viscosity (ML100℃ 1+4).
A carbon tetrachloride solution (viscosity at 50° C. of 4000 centipoise, concentration 11.1% by weight) of chlorinated ethylene/1-butene/ENB copolymer No. 65 was used. This raw material liquid was supplied to the apparatus at a rate of 16.7 kg/hr at 25°C, and continuous operation was performed by rotating the rotor at a speed of 1050 rpm under atmospheric pressure. At this time, the steam discharged from the steam outlet is condensed to recover 14.85 kg/hr of carbon tetrachloride, and 1.85 kg/hr of granular chlorinated ethylene/1-butene/ENB copolymer is collected from the granular elastic polymer outlet. Got hr. The granular product had a size of 0.5 to 4 mm and its volatile content was less than 0.5% by weight, but the elastomeric polymer was thermally degraded and the gel-like polymer, which is insoluble in toluene at the boiling point temperature, was 34.1% by weight.
Also occurred, and the color changed from black to color.

The actual power at this time is 4.3kw, and the idling power is
The actual power required after subtracting 1.68kw is 2.62kw, and the actual power per 1Kg/hr of elastic polymer is
It was 1.42kw.

Claims (1)

[Claims] 1. An organic solvent solution of an elastic polymer having a Mooney viscosity (ML100°C 1+4) of 10 or more, wherein the concentration of the elastic polymer is in the range of 5 to 50% by weight and the viscosity is in the range of 5 to 50% by weight. An organic solvent solution in the range of 500,000 centipoise or less is supplied to a centrifugal thin film evaporator.
The elastic gravity is characterized by applying a substantial power of 1.4 kw to 1.4 kw and applying centrifugal force to the solution to form a thin film while removing the solvent until the content of volatile components reaches a range of 10% by weight or less. Coalescence granulation method.