Production process for ethylene oxide resin

Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Treating polymer containing material or treating a solid...

Reexamination Certificate

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C528S491000, C528S503000, C526S064000, C526S071000

Reexamination Certificate

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06765084

ABSTRACT:

BACKGROUND OF THE INVENTION
A. Technical Field
The present invention relates to a production process for an ethylene oxide resin. More particularly, the present invention relates to a production process for an ethylene oxide resin, which comprises the step of carrying out devolatilization of a reaction liquid of the aforementioned resin as obtained by a polymerization reaction.
B. Background Art
Ethylene oxide resins have hitherto been useful as polymer materials in uses such as: polyurethane resins (e.g. adhesives, paints, sealing agents, elastomers, and floor-polishing agents); and besides hard, soft, or half-hard polyurethane resins; and further surfactants, sanitary products, drinking agents, lubricating oils, and engine-starting liquids. In recent years, they are further being thought to utilize in other various new uses in consideration of their wide-ranging usability.
As to a production process for the above ethylene oxide resin, especially as to purification and recovery of the resin after a polymerization reaction, have hitherto been generally known methods such as: (1) a method that involves precipitating the resin by pouring the polymerization reaction solution into a poor solvent after the solution polymerization, and carrying out filtration or centrifugation treatment, and thereafter subjecting the resultant resin to drying and pulverization; and (2) a method that involves carrying out filtration or centrifugation treatment of the polymerization reaction liquid after the precipitation polymerization, and subjecting the resultant recovered resin to drying and pulverization.
However, these methods (1) and (2) are carried out through the step of heat-drying and pulverizing the resin because of reasons such as obtaining a resin having high purity. Therefore, there has been danger of explosion as caused by the electrification and heating of the resin, wherein the electrification is due to such as electrostatic charge as generated then. Accordingly, in consideration of its prevention and safety, it has been generally essential to add a sufficient quantity of antistatic agent.
The addition of this antistatic agent causes such as the rise of the permittivity of the resin as obtained unnecessarily, the cause of lowering crosslinking degree and increasing moisture absorbency, and then the increase of the swelling capacity of the resin unnecessarily, and the lowering of the strength. Accordingly, the ethylene oxide resin containing the antistatic agent has been very difficult to utilize for such as protecting films for color filters in view of the rise of the permittivity, and it has been very unsuitable to use for such as materials of flexographic printing and electrolyte layers of polymer battery in view of the lowering of the strength.
In addition, the ethylene oxide resin is a resin having an ether bond in its main chain, and has a property such that it (the portion of the ether bond) is weak against the strong heating (high temperature) in view of its molecular structure. Therefore, there has been a problem such that the resin is decomposed during the above-mentioned heat-drying. In addition, in the above methods (1) and (2), new additional elements such as the poor solvent are necessary in addition to the heat-drying, and such as the increase of the cost of equipment accompanying at least two steps also has to be considered, and therefore there has also been a problem of the increase of the cost.
Furthermore, the ethylene oxide resin is frequently used in the form of a solution or paste when it is used. In such a case, when the ethylene oxide resin is once produced in a powdery form as is shown in the above methods (1) and (2), it is very difficult to carry out treatment in such as a case of adding a new solvent thereto in order to produce it in the form of a solution or paste, and therefore there is also a problem in view of usability.
On the one hand, when the ethylene oxide resin is used for uses such as protecting films for color filters and polyelectrolytes of polymer battery, the water content of the resin is requested to lowly suppress in not more than a definite amount. However, in a state such that various conditions for obtaining a desirable resin are satisfied, and further that the water content is lowly controlled, it has not been easy to obtain the above resin by the hitherto general methods.
When this water content cannot be controlled in not more than a definite amount, the permittivity of the resin is unnecessarily raised, and there has been a problem such that: when it is used for such as protecting films for color filters, the protecting films are converted to conductors, and thereby the lowering of the function is caused. In addition, when it cannot be controlled similarly, this water reacts with such as metal ion components and then such as hydroxides are formed. Therefore, there has been a problem such that: when the above resin is used, for example, for such as electrolyte layers for polymer battery, insulating layers are formed in the interface between the metal and the electrolyte layer, and thereby the voltage continues to increase under a constant electric current, and the cyclic efficiency of the battery is also deteriorated.
SUMMARY OF THE INVENTION
A. Object of the Invention
Accordingly, an object of the present invention is to provide a novel production process for an ethylene oxide resin, in which, when the ethylene oxide resin is obtained, it is arranged that the resin should contain no antistatic agent, and further its water content is also easily controlled in not more than a definite amount, and the thermal damage of the above resin is prevented, and besides, the reduction of the cost can also be actualized.
B. Disclosure of the Invention
The present inventors have diligently studied in order to solve the above-mentioned problems.
In the course, they have taken note of a treatment method that involves purifying and recovering a resin by devolatilization, which has hitherto been known as one step in a general production process for a resin, and they have studied the effect as obtained by this treatment method. When the ethylene oxide resin is obtained, there has hitherto been not at all knowledge that: the above resin is synthesized by polymerization using a solvent, and thereafter the resin is purified and recovered through the devolatilization treatment. The above procedure has not been carried out as a matter of fact, either. Considering various effects as obtained by the devolatilization treatment, the present inventors have thought out that: in order to solve the above problems, the treatment step by the devolatilization should be included just when the ethylene oxide resin is obtained.
That is to say, they have presumed that: the purification and recovery by heat-drying is not carried out due to the devolatilization treatment, and therefore it is not necessary to add the antistatic agent either, and there is no problem of the increase of the cost as mentioned above either, and the water content of the resin can also easily be adjusted while the devolatilization treatment is carried out.
Accordingly, when the ethylene oxide resin is actually produced, subsequently to obtaining a polymerization reaction liquid by the polymerization using a solvent, the devolatilization treatment of the above reaction liquid is carried out in combination. Then, they have confirmed that the above problems can be solved at a stroke, and have completed the present invention.
That is to say, a production process for an ethylene oxide resin, according to the present invention, comprises the step of carrying out devolatilization of a solvent from a polymerization reaction liquid containing the solvent, thereby obtaining the ethylene oxide resin; with the production process being characterized by arranging that: after the devolatilization, the resin should have a solvent concentration of 0.01 to 30 weight % and a water content of not more than 200 ppm, and the resin should contain no antistatic agent.
In addition, in the above present invention production

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