KR20210030794A - Preparation method for molded 2-cyanoethyl group-containing polymer foam - Google Patents

Abstract

The present invention relates to a method for producing a polymerization molded article containing a 2-cyanoethyl group, which can reduce the cost of reprocessing wastewater by reducing the amount of water, acetone and the like used during a purification process, and can obtain a highly purified 2-cyanoethyl group-containing polymer.

Description

Manufacturing method of polymerized molded product containing 2-cyanoethyl group {PREPARATION METHOD FOR MOLDED 2-CYANOETHYL GROUP-CONTAINING POLYMER FOAM}

The present invention relates to a production method capable of producing a highly purified 2-cyanoethyl group-containing polymerized molded article.

Recently, lithium secondary batteries have been applied to various uses/fields. In particular, as lithium secondary batteries become larger in capacity and higher energy density, interest in securing heat resistance of the separator is increasing.

Accordingly, it is a technology to increase the reliability of the battery by preventing the separator from shorting due to heat shrinkage or heat melting. A separator having a multilayered structure has been proposed.

In such a separator, as the heat-resistant porous layer, a 2-cyanoethyl group-containing polymer is widely used as a dispersant for evenly dispersing the inorganic material and the inorganic material.

Such a 2-cyanoethyl group-containing polymer can be prepared by reacting a hydroxyl group-containing compound such as acrylonitrile and polyvinyl alcohol under basic conditions in which a catalyst including caustic soda (NaOH) or the like is typically used. In addition, a solvent including acetone is typically used as a reaction medium for proceeding the reaction. As the reaction proceeds, a hydroxyl group is substituted with a cyanoethyl ether group to prepare a 2-cyanoethyl group-containing polymer such as cyanoethylpolyvinyl alcohol.

However, in this reaction process, inevitably, unreacted products of acrylonitrile, residual metal salts derived from catalysts, and by-products such as bis-cyanoethyl ether (BCE) may be generated. -Included in crude products containing cyanoethyl group-containing polymers.

Accordingly, in order to remove unreacted products, residual metal salts and by-products from the crude product including the 2-cyanoethyl group-containing polymer, the 2-cyanoethyl group-containing polymer was extracted by washing with a large amount of water after the reaction was completed. The method was applied. However, in this extraction process, in order to sufficiently remove the unreacted products, residual metal salts and by-products, a multi-step extraction process is required, and in the process, more than 50 times more water than the 2-cyanoethyl group-containing polymer is used. to be.

This is because during the substitution reaction, the hydroxyl group-containing compound and the catalyst are used in an aqueous solution state, so a large amount of water is already included in the crude product, and the solid content concentration of the 2-cyanoethyl group-containing polymer formed by the substitution reaction is 5 to 10. This is because it is relatively low, about weight percent. For this reason, even in a single extraction process, a large amount of water is inevitably used for precipitation/purification of the polymer.

As a result of the use of such a large amount of water, after the extraction process proceeds, the unreacted product of the acrylonitrile, the residual metal salt derived from the catalyst, and the malignant wastewater including by-products such as bis-cyanoethyl ether (especially nitrogen-containing Wastewater, etc.) is inevitably generated in large quantities, and a very large process cost is also required to purify such wastewater. Moreover, due to the extraction process using the multi-stage water, there is a disadvantage in that process energy consumption is also very large.

In addition, among the organic by-products contained in the crude product, bis-cyanoethyl ether occupies the largest amount, and such organic by-products and the like do not have a large solubility in water. Therefore, even if the number of repeated extractions is continuously increased in the conventional extraction method using water, it is very difficult to reduce the content of organic by-products such as bis-cyanoethyl ether to a certain level or less.

Accordingly, there is a need for development of a technology capable of obtaining a highly purified 2-cyanoethyl group-containing polymer by efficiently removing unreacted products and organic by-products during the purification and extraction process.

The present specification provides a method for producing a 2-cyanoethyl group-containing polymerized molded article, which can efficiently remove unreacted products and organic by-products, etc. during purification and extraction to obtain a highly purified 2-cyanoethyl group-containing polymerized molded article. I want to provide.

According to an aspect of the present invention, a first step of reacting an acrylonitrile and a hydroxyl group-containing compound to form a crude product comprising a 2-cyanoethyl group-containing polymer; A second step of evaporating the crude product under reduced pressure to obtain a crude product having a first concentration; A third step of separating the crude product of a first concentration into an oil phase and an aqueous phase, and removing the aqueous phase to obtain a crude product of a second concentration of the oil phase; There is provided a method for producing a polymerization molded article containing a 2-cyanoethyl group, comprising a fourth step of evaporating the crude product of the second concentration under reduced pressure conditions to obtain a crude product of a third concentration.

Here, the first, second, and third concentrations refer to the relative ratio of the 2-cyanoethyl group-containing polymer contained in the crude product obtained in each step, and the solution dissolved in the solvent used in each step It is a concept that includes not only the form but also the mixture in the form of solid content.

In this case, the 2-cyanoethyl group-containing polymer may include a first repeating unit represented by Formula 1 below and a second repeating unit represented by Formula 2 below.

[Formula 1]

In Formula 1,

R1 is hydrogen or an alkyl group having 1 to 3 carbon atoms;

[Formula 2]

In Chemical Formula 2,

R21 is hydrogen or an alkyl group having 1 to 3 carbon atoms;

R22 is an oxyethylene group.

In addition, the first concentration crude product may be obtained in an amount of about 50 to about 90 parts by weight, or about 60 to about 80 parts by weight, based on 100 parts by weight of the crude product.

In addition, the second concentration crude product may be obtained in an amount of about 10 to about 50 parts by weight, or about 20 to about 40 parts by weight, based on 100 parts by weight of the first concentration crude product.

In addition, the third concentration crude product may be obtained in an amount of about 50 to about 90 parts by weight, or about 50 to about 70 parts by weight, based on 100 parts by weight of the second concentration crude product.

According to an embodiment of the present invention, the method for producing a polymerized molded article containing a 2-cyanoethyl group may further include extruding the obtained crude product of the third concentration by vacuum extrusion molding.

In this case, the vacuum extrusion may include: i) leaving the crude product of a third concentration in a vacuum extruder under conditions of about 20 to about 120° C. and about 0.1 to about 5 torr; And ii) molding.

In addition, the step of standing may be more preferably carried out under the conditions of about 30 to about 110 ℃, or about 50 to about 110 ℃, it may be preferable to proceed for about 0.5 to about 2 hours.

According to another embodiment of the invention, the vacuum extrusion is performed using a T-die, and it may be preferable that the molded product is in a sheet form.

In the present invention, terms such as first and second are used to describe various components, and the terms are used only for the purpose of distinguishing one component from other components.

In addition, terms used in the present specification are only used to describe exemplary embodiments, and are not intended to limit the present invention.

Singular expressions include plural expressions unless the context clearly indicates otherwise.

In the present specification, terms such as "comprise", "include" or "have" are used to describe implemented features, numbers, steps, components, or combinations thereof, and one or more other features, numbers, and steps , Components, combinations thereof, or the possibility of addition are not excluded.

In addition, in the present specification, when each layer or element is referred to as being formed “on” or “on” each layer or element, it means that each layer or element is formed directly on each layer or element, or other It means that a layer or element may be additionally formed between each layer, on the object, or on the substrate.

The present invention will be described in detail below and exemplify specific embodiments, as various modifications can be made and various forms can be obtained. However, this does not limit the present invention to a specific form of disclosure, and it should be understood that all changes, equivalents, and substitutes included in the spirit and scope of the present invention are included.

Hereinafter, the present invention will be described in detail.

According to an aspect of the present invention, a first step of reacting an acrylonitrile and a hydroxyl group-containing compound to form a crude product comprising a 2-cyanoethyl group-containing polymer; A second step of evaporating the crude product under reduced pressure to obtain a crude product having a first concentration; A third step of separating the crude product of a first concentration into an oil phase and an aqueous phase, and removing the aqueous phase to obtain a crude product of a second concentration of the oil phase; There is provided a method for producing a polymerization molded article containing a 2-cyanoethyl group, comprising a fourth step of evaporating the crude product of the second concentration under reduced pressure conditions to obtain a crude product of a third concentration.

In contrast to the conventional extraction method using water, the inventors of the present invention, when using a vacuum evaporation process and an oil phase-aqueous separation process, etc. together, are purified with high purity without using separate water during the extraction process. It was confirmed that a 2-cyanoethyl group-containing polymer could be obtained, and the invention was completed.

In particular, the inventors of the present invention, as a result of performing the above process, as evidenced by the following examples, unreacted products such as acrylonitrile, which could not be achieved with the prior art using a large amount of water, And it was confirmed that organic by-products such as bis-cyanoethyl ether can be removed/purified with very high efficiency.

Accordingly, according to the present invention, a 2-cyanoethyl group-containing polymer purified with higher purity than the prior art can be obtained by completely replacing or at least partially replacing the existing extraction process using water.

Hereinafter, a method of manufacturing a polymerized molded article containing a 2-cyanoethyl group according to an embodiment will be described in each step.

In the production method of one embodiment, first, acrylonitrile and a hydroxyl group-containing compound are reacted to form a crude product including a 2-cyanoethyl group-containing polymer. This reaction step can be followed by a conventional method for producing a 2-cyanoethyl group-containing polymer, which will be briefly described in the following.

This reaction step may be prepared by Michael addition reaction of acrylonitrile and a compound (polymer) containing a hydroxyl group in the molecule as shown by the following reaction scheme, for example.

[Reaction Scheme]

In the above reaction formula, Polym-OH represents a hydroxyl group-containing compound (polymer), and Polym-O-CH2-CH2-CN represents a 2-cyanoethyl group-containing polymer.

More specifically, in the 2-cyanoethyl group-containing polymer, for example, a compound having a hydroxyl group in the molecule is dissolved in water, a catalyst such as caustic soda and/or sodium carbonate is added, followed by addition of acrylonitrile. And, it can be prepared by performing the reaction at about 0 to about 60 ℃ about 2 to about 12 hours.

In this case, acrylonitrile may be added in an amount of 1 to 10 parts by weight, or 5 to 10 parts by weight, based on 1 part by weight of the hydroxyl group-containing compound.

In addition, in the above reaction step, acrylonitrile may also serve as a solvent, and a dilute solvent that does not react with acrylonitrile, such as acetone, may be further added.

However, the invention is not limited to the reaction conditions described above, and specific reaction conditions such as temperature, time, and content of reactants may vary in terms of controlling the substitution ratio of the cyanoethyl group.

By the above reaction, a 2-cyanoethyl group-containing polymer including a first repeating unit represented by the following formula (1) and a second repeating unit represented by the following formula (2) may be produced.

[Formula 1]

In Formula 1,

R1 is hydrogen or an alkyl group having 1 to 3 carbon atoms;

[Formula 2]

In Chemical Formula 2,

R21 is hydrogen or an alkyl group having 1 to 3 carbon atoms;

R22 is an oxyethylene group.

Specifically, the repeating unit of Formula 1 can be seen as a portion remaining as it is in the hydroxyl group-containing compound because the above-described reaction does not proceed, and the repeating unit of Formula 2 is the Michael addition reaction described above for acrylonitrile in the hydroxyl group-containing compound. This can be seen as a substituted part.

After the above reaction is completed, the reaction termination liquid is separated into two layers, an aqueous layer and an organic layer containing a 2-cyanoethyl group-containing polymer.In the conventional case, the organic layer is taken out, and an anti-solvent, that is, extraction A solvent was added to precipitate a crude product to obtain a purified 2-cyanoethyl group-containing polymer.

In one embodiment of the present invention, the crude product obtained after completion of the reaction, that is, a 2-cyanoethyl group-containing polymer, an unreacted product, an organic by-product, other impurities, and the entire crude product containing all of various solvents such as water and acetone. Is first evaporated under reduced pressure conditions to obtain a crude product of a first concentration.

These decompression conditions may specifically mean a temperature of about 40 to about 60° C. and a pressure condition of about 0.3 to about 0.8 bar.

By evaporation under reduced pressure under such conditions, the concentration of the 2-cyanoethyl group-containing polymer may be relatively high in the crude product of the first concentration compared to the crude product obtained in the reaction. Specifically, the first concentration crude product may be obtained in an amount of about 50 to about 90 parts by weight, or about 60 to about 80 parts by weight, based on 100 parts by weight of the crude product.

In addition, by separating the oil phase and the aqueous phase contained in the crude product of the first concentration thus obtained, and removing the aqueous phase, a crude product of the second concentration of the oil phase may be obtained.

When the oil phase and the aqueous phase are separated, the 2-cyanoethyl group-containing polymer to be recovered is dispersed in the oil phase, and the oil phase has a relatively higher density than the aqueous phase, so the aqueous phase to be removed is distributed above the crude product of the first concentration. Then, the oil phase to be recovered is distributed under the crude product of the first concentration.

Accordingly, in order to separate the oil phase and the aqueous phase at this time, a liquid-liquid separator such as a decanter, a centrifugal separator, a column, or a distillation column may be used. In this case, the separation conditions and the like are not particularly limited, and may be based on conditions generally used in the technical field to which the present invention belongs.

By such oil-water separation, the second concentration crude product may be obtained in an amount of about 10 to about 50 parts by weight, or about 20 to about 40 parts by weight, based on 100 parts by weight of the first concentration crude product.

And, the crude product of the second concentration thus obtained can be evaporated once again under reduced pressure conditions to obtain a crude product of a third concentration.

These decompression conditions, specifically, may mean a temperature of about 40 to about 60 °C and a pressure condition of about 0.1 to about 0.6 bar.

By evaporation under reduced pressure under such conditions, the concentration of the 2-cyanoethyl group-containing polymer may be relatively high in the crude product of the third concentration compared to the crude product of the second concentration. Specifically, the third concentration crude product may be obtained in an amount of about 50 to about 90 parts by weight, or about 50 to about 70 parts by weight, based on 100 parts by weight of the second concentration crude product.

According to an embodiment of the present invention, the method for producing a polymerized molded article containing a 2-cyanoethyl group may further include extruding the obtained crude product of the third concentration by vacuum extrusion molding.

In this case, the vacuum extrusion may include: i) transferring the crude product of a third concentration to a vacuum extruder and leaving it in the vacuum extruder under conditions of about 10 to about 100° C. and about 0.1 to about 5 torr; And ii) molding.

In the step of transferring the crude product of the third concentration to the vacuum extruder, a gear pump or the like can be used.

And, the step of leaving it may be more preferable to proceed under the conditions of about 30 to about 95 ℃. In this standing step, impurities are naturally removed while the 2-cyanoethyl group-containing polymer remains in the vacuum extruder, so that the purity of the 2-cyanoethyl group-containing polymer can be further increased.

According to another embodiment of the invention, the vacuum extrusion is performed using a T-die, and it may be preferable that the molded product is in a sheet form. In this case, the vacuum extruder is a type having a twin screw or a disk-shaped degassing device, and it may be preferable to use a blade or the like having a large surface in terms of removing impurities.

As described above, the present invention efficiently removes unreacted products and organic by-products, etc., according to specific steps such as evaporation under reduced pressure and separation of an aqueous phase, to obtain a highly purified 2-cyanoethyl group-containing polymerized molded article. There is provided a method for producing a polymerized molded article containing a 2-cyanoethyl group.

Hereinafter, the action and effect of the invention will be described in more detail through specific embodiments of the invention. However, these embodiments are only presented as examples of the invention, and the scope of the invention is not determined thereby.

<Example>

Synthesis of 2-cyanoethyl group-containing polymer

1 part by weight of polyvinyl alcohol (PVA), 6 parts by weight of Acrylonitrile (AN), and 1.32 parts by weight of an aqueous solution of 1 wt% caustic soda were added to a reactor equipped with a stirrer and reacted at 50° C. for 100 minutes. 10 parts by weight of acetone and 3 parts by weight of water were added thereto, and after stirring for 40 minutes, 0.088 parts by weight of an acetic acid 25 wt% aqueous solution was added to terminate the reaction.

(Cyanoethyl substitution rate: 79%, MW: 408 K)

The reaction termination mixture is about 100 g of 2-cyanoethylpolyvinyl alcohol, about 700 g of acetone, about 200 g of acrylonitrile, about 250 g of water, and about 100 g of other organic by-products. Water and acetone are the amounts used to maintain the single phase in the reaction, and acrylonitrile is the unconverted unreacted product.

Comparative Example 1

About 2000 g of water was added to the reaction termination mixture to precipitate the polymer phase.

The recovered polymer phase was re-dissolved in about 300 g of acetone, and about 1000 g of water was added thereto to re-precipitate.

The polymer phase recovered once again was dissolved again in about 300 g of acetone, and about 1000 g of water was added thereto to re-precipitate.

The polymer phase obtained by one precipitation and two re-dissolution/re-precipitation was received in a tray, placed in a vacuum dryer at about 80° C. at about 1 torr, and dried for about 8 hours to obtain a 2-cyanoethyl group-containing polymer.

Comparative Example 2

In the same manner as in Comparative Example 1, except that about 1200 g of water was added instead of about 2000 g of water during the initial precipitation, a 2-cyanoethyl group-containing polymer was obtained.

Comparative Example 3

With respect to the reaction terminating mixture, it was evaporated under reduced pressure until the weight decreased by about 30% by weight.

This was put into a liquid-liquid separator, the upper water phase was removed, and the lower polymer phase was put into a washing tank.

About 1000 g of water was added to the washing tank to precipitate the polymer phase.

The recovered polymer phase was re-dissolved in about 300 g of acetone, and about 1000 g of water was added thereto to re-precipitate.

The polymer phase recovered once again was dissolved again in about 300 g of acetone, and about 1000 g of water was added thereto to re-precipitate.

The polymer phase obtained by one precipitation and two re-dissolution/re-precipitation was received in a tray, placed in a vacuum dryer at about 80° C. at about 1 torr, and dried for about 8 hours to obtain a 2-cyanoethyl group-containing polymer.

Example 1

With respect to the reaction terminating mixture, it was evaporated under reduced pressure conditions of about 50° C. and about 0.6 bar until the weight was reduced by about 30% by weight.

This was put into a liquid-liquid separator, the upper water phase was removed, and the lower polymer phase (about 30% by weight) was put into a vacuum container.

After evaporation under reduced pressure conditions of about 50° C. and about 0.3 bar until the weight was reduced by about 40% by weight, it was transferred to a vacuum extruder through a gear pump.

After transfer to the vacuum extruder, it was allowed to stand at about 40° C. and about 1 torr for about 1 hour to remove impurities, and a 2-cyanoethyl group-containing polymer sheet was obtained through a T-die. As the vacuum extruder, one equipped with a twin screw was used.

Example 2

When allowed to stand in a vacuum extruder, a 2-cyanoethyl group-containing polymer sheet was obtained in the same manner as in Example 1, except that it was allowed to stand for about 1 hour at about 60° C. for about 1 torr.

Example 3

When allowed to stand in a vacuum extruder, a 2-cyanoethyl group-containing polymer sheet was obtained in the same manner as in Example 1, except that it was allowed to stand for about 1 hour at about 80° C. for about 1 torr.

Example 4

When allowed to stand in a vacuum extruder, a 2-cyanoethyl group-containing polymer sheet was obtained in the same manner as in Example 1, except that it was allowed to stand for about 1 hour at about 100° C. about 1 torr.

For the polymers obtained in Examples and Comparative Examples, the concentrations of acrylonitrile, water, and other organic by-products in the 2-cyanoethyl group-containing polymer were confirmed.

The content of acrylonitrile and other organic by-products was analyzed using gas chromatography, and the content of water was analyzed using a Karl Fischer moisture meter.

The analysis results are summarized in Table 1 below.

Acrylonitrile
(ppmw) water
(ppmw) Organic by-products
(wt%) Comparative Example 1 20 40 0.5 Comparative Example 2 150 180 1.0 Comparative Example 3 20 30 0.5 Example 1 30 50 0.5 Example 2 10 20 0.1 Example 3 Less than 10 10 100 ppmw Example 4 Less than 10 10 200 ppmw

Referring to Table 1 above, it can be seen that in the case of Examples, the contents of unreacted acrylonitrile and water in the final product were significantly reduced according to specific steps such as evaporation and separation of the aqueous phase oil phase.

In particular, when undergoing a reprecipitation process using an anti-solvent as in the past, the solubility of organic by-products in water is not high, so even if the number of reprecipitation is increased, the amount of organic by-products contained in the final product does not decrease below a certain level. , In the case of the present embodiment, it can be clearly confirmed that the content of organic by-products can be reduced to ppm units.

Accordingly, the manufacturing method according to an embodiment of the present invention provides a polymer molded article containing 2-cyanoethyl group purified with high purity while being able to reduce wastewater reprocessing costs by reducing the amount of water and acetone used during the purification process. I think I can.

Claims (9)

A first step of reacting acrylonitrile and a hydroxyl group-containing compound to form a crude product comprising a 2-cyanoethyl group-containing polymer;
A second step of evaporating the crude product under reduced pressure to obtain a crude product having a first concentration;
A third step of separating the crude product of the first concentration into an oil phase and an aqueous phase, and removing the aqueous phase to obtain a crude product of a second concentration of the oil phase;
And a fourth step of evaporating the second concentration of the crude product under reduced pressure conditions to obtain a third concentration of the crude product.
The method of claim 1,
The 2-cyanoethyl group-containing polymer includes a first repeating unit represented by the following formula (1) and a second repeating unit represented by the following formula (2):
[Formula 1]

In Formula 1,
R1 is hydrogen or an alkyl group having 1 to 3 carbon atoms;
[Formula 2]

In Chemical Formula 2,
R21 is hydrogen or an alkyl group having 1 to 3 carbon atoms;
R22 is an oxyethylene group.
The method of claim 1,
The first concentration crude product is obtained in 50 to 90 parts by weight relative to 100 parts by weight of the crude product, a method for producing a polymerization molded article containing a 2-cyanoethyl group.
The method of claim 1,
The second concentration crude product is obtained in an amount of 10 to 50 parts by weight, based on 100 parts by weight of the first concentration crude product.
The method of claim 1,
The third concentration crude product is obtained in an amount of 50 to 90 parts by weight, based on 100 parts by weight of the second concentration crude product.
The method of claim 1,
Further comprising the step of extruding the obtained crude product of the third concentration by vacuum extrusion,
Method for producing a polymerization molded article containing a 2-cyanoethyl group
The method of claim 6,
The vacuum extrusion molding,
i) leaving the crude product of a third concentration in a vacuum extruder under conditions of 20 to 120° C. and 0.1 to 5 torr; And
ii) A method for producing a polymerized molded article containing a 2-cyanoethyl group comprising the step of molding.
The method of claim 7, wherein the step of leaving is carried out under conditions of 30 to 95°C.
The method of claim 6,
The vacuum extrusion molding is performed using a T-die, and the molded product is in the form of a sheet, a method for producing a polymerized molded product containing a 2-cyanoethyl group.