KR102551395B1 - Preparation method for 2-cyanoethyl group-containing polymer - Google Patents

Abstract

The present invention is a high purity purified 2-siar that can reduce the amount of water used during the purification process to reduce the cost of reprocessing wastewater and can improve the dispersibility of the slurry when manufacturing a non-aqueous electrolyte battery separator with a low content of residual inorganic metal salt. It relates to a method for producing a noethyl group-containing polymer.

Description

Method for producing 2-cyanoethyl group-containing polymer {PREPARATION METHOD FOR 2-CYANOETHYL GROUP-CONTAINING POLYMER}

The present invention relates to a method for producing a 2-cyanoethyl group-containing polymer capable of producing a highly purified 2-cyanoethyl group-containing polymer while reducing wastewater reprocessing costs by reducing water consumption during the purification process. .

Separator for battery electrolyte is an inactive material that does not participate in the electrochemical reaction, but it should provide a path for lithium ions to move so that the battery can operate. It is one of the key materials of batteries that have a great impact.

Polyolefin-based separators may have problems due to heat shrinkage, so the stability of the separator is secured by introducing an inorganic material layer.

A dispersant is used to evenly introduce the inorganic material layer into the separator. The stability of the battery separator is secured only when the dispersing ability of the dispersant is at an appropriate level. problem arises.

A cyano polymer is mainly applied as the dispersant, and a base catalyst is used for its preparation. Such a 2-cyanoethyl group-containing polymer may 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) is used. In addition, a solvent containing acetone is typically used as a reaction medium for the progress of such a reaction. As this reaction proceeds, a 2-cyanoethyl group-containing polymer such as cyanoethyl polyvinyl alcohol can be prepared by substituting a hydroxyl group with a cyanoethyl ether group.

When such caustic soda is used as a base catalyst, the efficiency is good, but there is a disadvantage in that a large amount of water must be used during purification and washing.

In addition, in the above reaction process, by-products such as unreacted acrylonitrile, residual metal salts derived from catalysts, and bis-cyanoethyl ether (BCE) may be produced. - Included in crude products containing cyanoethyl group-containing polymers.

Therefore, conventionally, in order to remove unreacted materials, residual metal salts, by-products, etc. from the crude product including the 2-cyanoethyl group-containing polymer, after the completion of the reaction, a water washing process using a large amount of water is performed to obtain the 2-cyanoethyl group-containing polymer. The extraction method was applied. However, in this extraction process, in order to sufficiently remove the unreacted substances, residual metal salts, and by-products, a multi-step extraction process is required, and 50 times more water is used than the 2-cyanoethyl group-containing polymer in the process. am.

As a result of such a large amount of water being used, after the extraction process, malignant wastewater (in particular, nitrogen-containing Wastewater, etc.) is inevitably generated in large quantities, and a very large process cost is required for the purification of such wastewater. Moreover, due to the multi-step extraction process using water, there is a disadvantage in that process energy consumption is also very large.

In addition, there are cases where quaternary ammonium salts (eg, benzyltriethylammonium chloride, benzyltrimethylammonium chloride, benzyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, etc.) are used as existing organic catalysts, but physical properties such as dispersibility may be poor. .

Accordingly, there is a need to develop a technique capable of reducing the amount of water used in the purification and extraction processes and obtaining a highly purified 2-cyanoethyl group-containing polymer having excellent dispersibility.

In the present specification, by-products, etc. are efficiently removed without using water in the purification and extraction processes, and the content of residual inorganic metal salt is small, and the dispersibility of the slurry can be improved during the manufacture of a non-aqueous electrolyte battery separator. - It is intended to provide a method for producing a cyanoethyl group-containing polymer.

According to one aspect of the present invention,

reacting acrylonitrile and a hydroxyl group-containing compound in an organic solvent in the presence of an organic catalyst including 1,1,3,3-tetramethylguanidine to form a crude product including a 2-cyanoethyl group-containing polymer; and

Extracting the crude product with an extraction solvent including an organic solvent to form a purified 2-cyanoethyl group-containing polymer,

A method for producing a 2-cyanoethyl group-containing polymer is provided.

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 another.

In addition, terms used in this 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 dictates otherwise. In this specification, terms such as "comprise", "comprise" or "having" are intended to indicate that there is an embodied feature, number, step, component, or combination thereof, but one or more other features or It should be understood that the presence or addition of numbers, steps, components, or combinations thereof is not precluded.

Since the present invention can have various changes and various forms, specific embodiments will be exemplified and described in detail below. However, it should be understood that this is not intended to limit the present invention to the specific disclosed form, and includes all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Hereinafter, a method for preparing a 2-cyanoethyl group-containing polymer according to specific embodiments of the present invention will be described in more detail.

According to one aspect of the present invention,

reacting acrylonitrile and a hydroxyl group-containing compound in an organic solvent in the presence of an organic catalyst including 1,1,3,3-tetramethylguanidine to form a crude product including a 2-cyanoethyl group-containing polymer; and

Extracting the crude product with an extraction solvent including an organic solvent to form a purified 2-cyanoethyl group-containing polymer,

A method for preparing a 2-cyanoethyl group-containing polymer is provided.

In addition, the step of forming a crude product including the 2-cyanoethyl group-containing polymer,

Injecting acrylonitrile into an aqueous solution containing a hydroxyl group-containing compound and introducing an organic catalyst containing 1,1,3,3-tetramethylguanidine to perform a first reaction; and

It is preferable to include the step of introducing an organic solvent in a state where the temperature of the first reaction mixture is lowered and performing a second reaction.

As a result of continuous experiments by the present inventors, when a specific guanidine-based organic base catalyst is used for the production of a polymer containing a cyanoethyl group, except for water used as a substitution reaction solvent, there is no The present invention was completed by confirming that a highly purified 2-cyanoethyl group-containing polymer could be obtained while not using water in the extraction process or greatly reducing the amount of water used because a water washing process was not required.

That is, the present invention can provide a method capable of minimizing water consumption by preparing a cyano polymer by applying an organic catalyst instead of the existing inorganic catalyst (NaOH). In particular, the process of washing with a large amount of water to remove the inorganic salt remaining in the substitution reactant during the purification and washing process can be excluded from the source.

Therefore, according to the present invention, it is possible to obtain a purified 2-cyanoethyl group-containing polymer having a purity equal to or higher than that of the prior art by completely replacing or at least partially replacing the existing extraction process using water.

In addition, in the present invention, when the cyano group substitution rate is 70%, it is possible to provide a method capable of implementing excellent dispersibility compared to the existing ones.

In addition, as demonstrated through the following examples, the inventors of the present invention, as a result of using the organic catalyst, in accordance with the prior art using a large amount of water, the residuals derived from the unreacted material of the acrylonitrile, the catalyst, etc. It was confirmed that metal salts can be effectively removed/purified from the crude product of the polymer.

Hereinafter, a method for preparing a 2-cyanoethyl group-containing polymer according to an embodiment will be described step by step.

The present invention is characterized by using an organic base catalyst having a guanidine structure in the process of preparing a polymer containing a cyanoethyl group using acrylonitrile and a compound containing a hydroxyl group.

According to this method, the present invention can greatly reduce the amount of water used compared to the conventional method using a conventional quaternary ammonium salt while excluding the use of an existing inorganic catalyst. In addition, the present invention can provide a polymer with easy removal of reaction by-products and, in particular, a small content of residual inorganic metal salt. In addition, when the 2-cyanoethyl group-containing polymer is used as a dispersant in a dispersant composition for non-aqueous electrolyte battery separators, it can contribute to manufacturing a battery separator with excellent performance by exhibiting dispersibility equal to or higher than that of the prior art.

Preferably, the organic catalyst includes guanidine structured 1,1,3,3-tetramethylguanidine (TMG).

In the method of the present invention, acrylonitrile and a hydroxyl group-containing compound are reacted in an organic solvent in the presence of an organic catalyst including 1,1,3,3-tetramethylguanidine to form a 2-cyanoethyl group-containing polymer. The steps to form the crude product are carried out.

The organic catalyst may be used in an amount of 0.01 to 0.05 parts by weight based on 1 part by weight of the hydroxyl group-containing compound (eg, based on the initial PVA polymer). In addition, the organic catalyst may be an aqueous solution containing 1 to 10% by weight of 1,1,3,3-tetramethylguanidine and 99 to 90% by weight of water at a concentration of 1 to 10% by weight. In addition, the organic catalyst may be an aqueous solution at a concentration of 1 to 5% by weight or 1 to 3% by weight for efficiency.

Further, in the production method of the present invention, when reacting acrylonitrile and a hydroxyl group-containing compound to form a crude product including a 2-cyanoethyl group-containing polymer, instead of mixing and reacting all components at once as in the prior art, two There is a characteristic that progresses through stages.

That is, the present invention can provide a polymer having an appropriate cyano group substitution rate for use as a dispersant by conducting a primary reaction by adding an organic catalyst to the above two reactants and performing a secondary reaction again at a lowered temperature.

For example, in the step of forming a crude product including a 2-cyanoethyl group-containing polymer, acrylonitrile is added to an aqueous solution containing a hydroxyl group-containing compound, and an organic product containing 1,1,3,3-tetramethylguanidine is added. Injecting a catalyst to perform a primary reaction; and injecting an organic solvent in a state in which the temperature of the first reaction mixture is lowered and performing a second reaction.

The primary reaction includes a substitution reaction of acrylonitrile and a hydroxyl group-containing compound.

The first reaction may include performing at a temperature of 60 to 80 °C for 30 minutes to 120 minutes. If the temperature during the first reaction is 60 ° C or less, there is a problem that PVA is not well dissolved in water, and if it is 80 ° C or more, there is a risk of vaporization exceeding the boiling point of acrylonitrile.

The secondary reaction is carried out by adding an organic solvent in a state where the temperature of the primary reaction mixture is lowered to the range of 40 to 60 ° C., and 30 minutes to 300 minutes It may include steps performed during

When the temperature is lower than 40° C. during the secondary reaction, the substitution rate deteriorates, and when the temperature exceeds 60° C., it is difficult to control the reaction and there is a problem that the organic solvent introduced in the secondary reaction vaporizes. If the reaction time of the secondary reaction is 30 minutes or less, there is a problem of not obtaining a desired level of substitution, and if it is more than 300 minutes, a large amount of side reactants are generated, and there is a problem of a similarly low substitution rate.

That is, in the present invention, after the first reaction and the second reaction, after the organic solvent (preferably, acetone) is added, the optimal reaction time is derived, so that a polymer having a cyanoethyl group substitution rate capable of exhibiting the desired physical property level can be easily provided.

At this time, 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 can also serve as a solvent, but a diluting solvent that does not react with acrylonitrile, such as acetone, can be further added.

In addition, any hydroxyl group-containing compound as a raw material can be used as long as it can obtain the above-described predetermined molecular weight distribution and weight average molecular weight so as to be able to produce a 2-cyanoethyl group-containing polymer. For example, a polyvinyl alcohol-based polymer may be used as a hydroxyl group-containing compound, which may be used in an aqueous solution for a substitution reaction.

Also, in the step of forming the crude product including the 2-cyanoethyl group-containing polymer, a conventional method may be used to terminate the secondary reaction. For example, the reaction may be terminated by adding an aqueous acetic acid solution of a certain concentration to the reaction mixture.

On the other hand, after forming a crude product containing a 2-cyanoethyl group-containing polymer through the above-described reaction step, the crude product is extracted with an extraction solvent including an organic solvent to form a purified 2-cyanoethyl group-containing polymer. go through the steps

After completion of the reaction, the reaction solution is separated into two layers, an aqueous layer and an organic layer containing a 2-cyanoethyl group-containing polymer, and water may be included, but in the present invention, purification and washing are performed using only an organic solvent without using additional water. However, it is possible to effectively remove unreacted materials and residual metals.

In particular, the extraction solvent used in one embodiment of the present invention may be the same kind as the organic solvent used in the above-described substitution reaction. For example, the extraction solvent may include one or more organic solvents selected from the group consisting of isopropyl alcohol, acetone, n-butanol, ethanol, toluene, and methyl isobutyl ketone, and the extraction step may be performed multiple times. Preferably, the extraction solvent may be used multiple times in the extraction step sequentially using isopropyl alcohol and acetone.

In the above extraction step, the extraction solvent may be a solvent for use in purifying and washing the crude product. In addition, the extraction solvent may include only the specific organic solvent described above, but the organic solvent may be used as a mixed solvent, and the extraction step may be performed a plurality of times, for example, 2 to 7 times, or 2 to 5 times. The circuit may proceed.

In a specific example of this extraction method, the extraction solvent includes isopropyl alcohol and acetone among the organic solvents, which may be used alone or in a mixture, and the extraction step is performed 2 to 5 times, or 3 to 4 times. can proceed

In addition, the organic solvent used in the extraction may be used in an amount of about 50 to about 300 parts by weight, preferably about 50 to about 200 parts by weight, based on 100 parts by weight of the crude product.

And, the method for preparing the 2-cyanoethyl group-containing polymer may further include, after the extraction step, collecting and drying the 2-cyanoethyl group-containing polymer to obtain a purified 2-cyanoethyl group-containing polymer. can

In this manufacturing method, each of the above-described steps may be performed as a continuous process, and the high-purity 2-cyanoethyl group-containing polymer provided in the method may be used very preferably as a dispersant for a separator of a lithium secondary battery. .

According to this method, the purified 2-cyanoethyl group-containing polymer may contain less than 3 ppm of residual metal salt.

On the other hand, these specific examples of the present invention may be appropriately selected in consideration of the type of 2-cyanoethyl group-containing polymer, substitution rate or other process variables, etc., depending on the conditions of using the above-described organic catalyst. Even with the method, the purity of the 2-cyanoethyl group-containing polymer can be greatly increased. In addition, since the organic solvent used for removing unreacted substances and organic by-products in the specific example of the present invention is relatively easy to reprocess compared to water, the wastewater reprocessing process cost or energy that inevitably occurs in the existing process can greatly save.

Examples of the 2-cyanoethyl group-containing polymer that can be produced through the above-described process include cyanoethyl pullulan, cyanoethyl cellulose, cyanoethyl dihydroxypropyl pullulan, cyanoethylhydroxyethyl cellulose, and cyanoethyl It may be cyanoethyl polysaccharide such as hydroxypropyl cellulose or cyanoethyl starch, or cyanoethyl polyvinyl alcohol, and may be cyanoethyl polyvinyl alcohol appropriately. The type of the 2-cyanoethyl group-containing polymer may vary depending on the type of the hydroxyl group-containing compound, and the cyanoethyl polyvinyl alcohol can be obtained by using a polyvinyl alcohol-based polymer as the hydroxyl group-containing compound.

In addition, the 2-cyanoethyl group-containing polymer has a weight average molecular weight of i) a weight average molecular weight of 250,000 to 400,000, ii) a PDI of 1.5 to 2.5, and iii) a cyanoethyl group substitution rate of 60 to 80%. there is. Depending on complex factors such as the cyanoethyl group substitution rate in the above range and the molecular weight of the polymer, it can be suitably used as a dispersant in the separator. Preferably, the 2-cyanoethyl group-containing polymer may have a weight average molecular weight of 300,000 to 350,000.

The molecular weight is a value measured by gel permeation chromatography (GPC).

The cyanoethyl group substitution rate may be expressed as a ratio (%) of the number of moles of hydroxyl groups substituted with cyanoethyl groups to the number of moles of hydroxyl groups present per monomer unit of the hydroxyl group-containing compound as a starting material. This substitution rate can be calculated from the nitrogen content of the 2-cyanoethyl group-containing polymer measured by the Kjeldahl method.

Dispersant composition for non-aqueous electrolyte battery separators

According to one embodiment of the present invention, it is possible to provide a method of using the above-described 2-cyanoethyl group-containing polymer as a dispersant.

According to one embodiment of the present invention, i) the weight average molecular weight is 250,000 to 400,000 ii) the PDI is 1.5 to 2.5, iii) the cyanoethyl group substitution rate is in the range of 60 to 80%, and the residual metal salt is less than 3 ppm A dispersant composition for a non-aqueous electrolyte battery separator, which includes at least one polymer containing a 2-cyanoethyl group and exhibits a sedimentation rate of 13 (μm/s) or less, may be provided.

Since the present invention provides a slurry-phase dispersant composition having excellent dispersibility, it is possible to firmly adhere the inorganic filler when manufacturing a separator for a non-aqueous electrolyte battery.

For example, in the dispersant composition, a dispersant (solid particles) is mixed with a binder, a solvent, and an inorganic filler, and when left for a certain period of time, the solid content settles due to gravity, and thus the lower layer mainly containing the solid particles and It can be separated into an upper layer mainly containing a solvent or the like. At this time, when the sedimentation rate according to gravity is measured using a dispersion analyzer (LUM GmbH) equipment, the dispersant composition includes the 2-cyanoethyl group-containing polymer according to the above method, 11 (㎛ / s) or less, or A sedimentation rate of 5 to 10.8 (μm/s) may be exhibited.

In addition, the dispersant composition may exhibit a particle size distribution having an average particle diameter of Dx(10) of 1.4 μm or less, Dx(50) of 3.8 μm or less, and Dx(90) of 7.5 μm or less. Preferably, the dispersant composition may exhibit a particle size distribution having an average particle diameter of Dx(10) of 0.5 to 1.35 μm, Dx(50) of 1.5 to 3.78 μm, and Dx(90) of 3.5 to 7.4 μm. The Dx (10) (μm), Dx (50) (μm), and Dx (90) (μm) are values obtained by dispersing the particles in the slurry, and the particles corresponding to 10%, 50%, and 90%, respectively It may mean a distributed average particle diameter.

Meanwhile, the dispersant composition and a method for preparing a separator for a non-aqueous electrolyte battery using the dispersant composition may be provided according to a method well known in the art.

In addition, the dispersant composition may further include a binder.

The 2-cyanoethyl group-containing polymer is, for example, as described above, cyanoethyl pullulan, cyanoethyl cellulose, cyanoethyldihydroxypropyl pullulan, cyanoethylhydroxyethylcellulose, cyanoethylhydride It may be cyanoethyl polysaccharides such as oxypropyl cellulose and cyanoethyl starch, cyanoethyl polyvinyl alcohol, and the like, preferably cyanoethyl polyvinyl alcohol.

Specifically, cyanoethyl polyvinyl alcohol has strong bonding strength between inorganic fillers and flexibility, preventing defects such as cracking when bending or folding the separator.

The binder is an ethylene-vinyl acetate copolymer (EVA, having a structural unit derived from vinyl acetate of 20 to 35 mol%), an acrylate copolymer, styrene butadiene rubber (SBR), polyvinyl butyral (PVB), polyvinyl Pyrrolidone (PVP), polyurethane, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trichloroethylene, polyvinylidene fluoride-chlorotrifluoroethylene copolymer, polyvinylidene fluoride -Hexafluoropropylene, polyvinylidene fluoride-trichloroethylene, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, etc. may be selectively additionally used as needed. When these binders are additionally used, 10 to 1000 parts by weight of the resin may be mixed and used based on 100 parts by weight of the 2-cyanoethyl group-containing polymer.

In addition, when a non-aqueous electrolyte battery separator is manufactured using the dispersant composition, a heat-resistant porous layer may be included by coating the porous substrate.

That is, the method for forming the heat-resistant porous layer is not particularly limited. For example, it can be formed by coating a porous substrate with a slurry obtained by dispersing an inorganic filler in the dispersant composition and then drying and removing the solvent.

In addition, the inorganic filler is not particularly limited as long as it has a melting point of about 200 ° C. or higher, has high electrical insulation, is electrochemically stable, and is stable in an electrolyte solution or a solvent used in a slurry for forming a heat-resistant porous layer. Examples of the inorganic filler include iron oxide, SiO ₂ (silica), Al ₂ O ₃ (alumina), TiO ₂ , BaTiO ₃ , ZrO, PB (Mg ₃ Nb _2/3 )O ₃ -PbTiO ₃ (PMN-PT), half inorganic oxide fine particles such as niacin (HfO ₂ ), SrTiO ₃ , SnO ₂ , CeO ₂ , MgO, NiO, CaO, ZnO, ZrO ₂ , and Y ₂ O ₃ ; fine particles of inorganic nitrides such as aluminum nitride and silicon nitride; Poorly soluble ion crystal fine particles, such as calcium fluoride, barium fluoride, and barium sulfate; covalently bonded crystal fine particles such as silicon and diamond; fine clay particles such as talc and montmorillonite; Mineral resource-derived materials such as boehmite, zeolite, apatite, kaolin, mullite, spinel, olivine, sericite, bentonite, or lithium titanium phosphate (Li _x Ti _y (PO ₄ ) ₃ , wherein x and y are 0 < A number that satisfies x<2, 0<y<3); or combinations thereof.

The particle diameter of the inorganic filler is not particularly limited, but in order to form a heat-resistant porous layer with a uniform thickness and obtain an appropriate porosity, an average particle diameter of about 5 nm to about 5 μm may be used, and more specifically about It may be from 0.01 to about 1 μm. On the other hand, the average particle diameter here can be measured by a measuring device based on the laser diffraction scattering method. If the diameter of the inorganic filler is less than about 5 nm, the dispersibility of the inorganic filler is lowered, making it difficult to control the physical properties of the separator. Smoothness tends to decrease, and a heat-resistant porous layer produced with the same solid powder content may become thick and mechanical properties may deteriorate.

Here, the dispersant composition may further include a solvent, and such a solvent is not particularly limited as long as it can dissolve the above-described 2-cyanoethyl group-containing polymer. For example, acetone, tetrahydrofuran, cyclohexanone, ethylene glycol monomethyl ether, methyl ethyl ketone, acetonitrile, furfuryl alcohol, tetrahydrofurfuryl alcohol, methyl acetoacetate, nitromethane, N, N-dimethylformamide ( DMF), N-methyl-2-pyrrolidone, γ-butyrolactone, or propylene carbonate. Meanwhile, the solvent may be mixed in an amount of about 300 to about 5000 parts by weight based on 100 parts by weight of the entire resin including the 2-cyanoethyl group-containing polymer.

As the porous substrate, any film-like material well known in the art may be used. For example, the porous substrate may be low density polyethylene, high molecular weight polyethylene, ultra high molecular weight polyethylene, polyolefins such as polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyacetals, polyamides, polycarbonates, It may have a material such as polyimide, polyether ether ketone, polyether sulfone, or a combination thereof.

As described above, the present invention can provide a method capable of minimizing water consumption by preparing a 2-cyanoethyl group-containing polymer by applying a specific organic catalyst having a guandinine structure instead of the conventional inorganic catalyst (NaOH). Therefore, since the present invention does not require the use of a large amount of water in the process of purifying the 2-cyanoethyl group-containing polymer, it is possible to produce a 2-cyanoethyl group-containing polymer purified to a higher purity than before, while generating It is possible to provide a method for producing a 2-cyanoethyl group-containing polymer that can greatly reduce the cost of reprocessing wastewater. In particular, the 2-cyanoethyl group-containing polymer of the present invention not only has a small residual metal component, but also improves the dispersibility of the dispersant composition for nonaqueous electrolyte battery separators because the particle size and sedimentation rate of particles in the slurry are relatively smaller than those of the prior art when used as a dispersant. can make it

Hereinafter, the action and effect of the invention will be described in more detail through specific examples 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>

The cyanoethyl substitution rate was calculated as a percentage ratio with respect to the number of moles of hydroxyl groups originally present per repeating unit of the polymer after obtaining the nitrogen content through the Kjeldahl Method for the cyanoethylated polyvinyl alcohol produced in the following Synthesis Example.

1) The weight average molecular weight value was analyzed through GPC, and the measurement conditions of GPC are as follows.

*Device: Gel Permeation Chromatography GPC (measurement device name: Alliance e2695; manufacturer: WATERS)

*Detector: Differential refractive index detector (Measurement device name: Waters Alliance e2695)

*Column: DMF column

*Flow rate: 1 mL/min

*Column temperature: 65 ℃

*Injection amount: 0.100 mL

*Sample for standardization: polystyrene

2) Also, the number average molecular weight was measured under the same conditions.

3) PDI was expressed as a ratio (Mw/Mn) of weight average molecular weight and number average molecular weight.

Example 1

Based on 1 part by weight of polyvinyl alcohol (PVA; DP1000), 5 parts by weight of water was put into a reactor equipped with a stirrer, and stirred at 70° C. for 1 hour to dissolve PVA.

Thereafter, 6 parts by weight of Acrylonitrile (AN) was added to the PVA-containing solution, and after stirring for 30 minutes, 3.8 parts by weight of a 1 wt % aqueous solution of 1,1,3,3-tetramethylguanidine (hereinafter referred to as TMG) as a catalyst was added and 70 The substitution reaction was carried out at °C for 90 minutes.

After the substitution reaction, 8 parts by weight of acetone was added and reacted for 60 minutes while the temperature of the reaction mixture was reduced to 50°C. Then, 7.92 parts by weight of a 25 wt% acetic acid aqueous solution was added to the reaction mixture to terminate the reaction, thereby preparing a crude product.

(Cyanoethylated PVA: 72%, MW: 340K, PDI: 1.59)

The crude product (solution state) including the 2-cyanoethyl group-containing polymer prepared above was purified and washed three times using acetone and isopropyl alcohol (IPA) as a set, and the acetone solution was dried to contain 2-cyanoethyl group. A polymer (cyanoethyl polyvinyl alcohol) was obtained (24 h drying in 90° C. vacuum).

Example 2

Based on 1 part by weight of polyvinyl alcohol (PVA; DP1000), 5 parts by weight of water was put into a reactor equipped with a stirrer, and stirred at 70° C. for 1 hour to dissolve PVA.

Thereafter, 6 parts by weight of Acrylonitrile (AN) was added to the PVA-containing solution, and after stirring for 30 minutes, 3.8 parts by weight of a 1 wt % aqueous solution of 1,1,3,3-tetramethylguanidine (hereinafter referred to as TMG) as a catalyst was added and 70 The substitution reaction was carried out at °C for 90 minutes.

After the substitution reaction, 8 parts by weight of acetone was added and reacted for 180 minutes while the temperature of the reaction mixture was reduced to 50°C. Then, 7.92 parts by weight of a 25 wt% acetic acid aqueous solution was added to the reaction mixture to terminate the reaction, thereby preparing a crude product.

(Cyanoethylated PVA: 65.4%, MW: 310K, PDI: 1.76)

The crude product (solution state) including the 2-cyanoethyl group-containing polymer prepared above was purified and washed three times using acetone and isopropyl alcohol (IPA) as a set, and the acetone solution was dried to contain 2-cyanoethyl group. A polymer (cyanoethyl polyvinyl alcohol) was obtained (24 h drying in 90° C. vacuum).

Comparative Example 1

1 part by weight of polyvinyl alcohol (PVA), 6 parts by weight of Acrylonitrile (AN), and 1.32 parts by weight of a 1 wt% aqueous solution of caustic soda were introduced into 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, 8.8 parts by weight of a 25 wt% acetic acid aqueous solution was added to terminate the reaction to prepare a crude product.

(Cyanoethylated PVA: 77.7%, MW: 318K, PDI: 1.7)

The crude product of the 2-cyanoethyl group-containing polymer prepared above was purified and washed 7 times using a set of water and acetone, and then dried (drying in a vacuum at 90° C. for 24 hours).

Reference example 1

1 part by weight of polyvinyl alcohol (PVA), 6 parts by weight of Acrylonitrile (AN), and 1.33 parts by weight of benzyl trimethyl ammonium hydroxide (BTMAH) were added, and reacted at 50° C. for 100 minutes. 10 parts by weight of acetone and 0.3 parts by weight of water were added thereto, and after stirring for 300 minutes, 8.8 parts by weight of a 25 wt% acetic acid aqueous solution was added to terminate the reaction to prepare a crude product.

(Cyanoethylated PVA: 80.3%, MW: 317K, PDI: 1.78)

The crude product of the 2-cyanoethyl group-containing polymer prepared above was purified and washed three times using acetone and isopropyl alcohol (IPA) as a set, and then the acetone solution was dried to obtain a 2-cyanoethyl group-containing polymer (cyano ethyl polyvinyl alcohol) was obtained (24 h drying in 90 ° C. vacuum).

Example 3

A dispersant composition for a non-aqueous electrolyte battery separator was prepared using the 2-cyanoethyl group-containing polymer of Example 1 as a dispersant.

That is, 1 part by weight of the dispersant of Example 1 and 7 parts by weight of polyvinylidene fluoride-hexafluoropropylene as a polymer binder were added to 320 parts by weight of acetone and dissolved at 50° C. for 12 hours.

Here, 72 parts by weight of Al ₂ O ₃ (number average particle diameter: 500 nm) was added as inorganic particles, and a slurry was prepared using a ball mill method, and then the particle size was analyzed and the sedimentation rate was measured.

In addition, the slurry prepared above was coated on a polyethylene porous membrane (C210, Celgard Co., Ltd.) having a thickness of 16 μm using a dip coating method to prepare a separator for a non-aqueous electrolyte battery.

Example 4

A dispersant composition for a non-aqueous electrolyte battery separator and a separator were provided in the same manner as in Example 3, except that the crude product of the 2-cyanoethyl group-containing polymer of Example 2 was used.

Comparative Example 2

A dispersant composition for a non-aqueous electrolyte battery separator and a separator were provided in the same manner as in Example 3, except that the crude product of the 2-cyanoethyl group-containing polymer of Comparative Example 1 was used.

Comparative Example 3

A dispersant composition for a non-aqueous electrolyte battery separator and a separator were provided in the same manner as in Example 3, except that the crude product of the 2-cyanoethyl group-containing polymer of Reference Example 1 was used.

[Test Example]

inorganic analysis

For the 2-cyanoethyl group-containing polymer (cyanoethyl polyvinyl alcohol) obtained after drying in Examples 1 and 2 and Comparative Example 1 and Reference Example 1, inorganic analysis equipment (ICP-OES, Optima 8300DV, Perkinelmer) was used. The inorganic component (Na analysis) content in the polymer was measured using

Dispersion evaluation

In order to measure the dispersing ability, using the slurries obtained in Examples 3 and 4 and Comparative Examples 2 and 3, the particle size was analyzed and the sedimentation rate was evaluated by the following method. The average particle diameter of the slurry was measured using a particle size analyzer (Mastersizer 3000 (Malvern), Malvern). It can be said that the smaller the average particle diameter, the better the dispersing ability of the dispersing agent.

At this time, Dx (10) (㎛), Dx (50) (㎛), Dx (90) (㎛) are the values obtained by dispersing the particles in the slurry, respectively 10%, 50% and 90% of the particles corresponding to It may mean the average particle diameter in which they are distributed.

The sedimentation rate of the slurry was measured using a dispersion analyzer (LUM GmbH) equipment. It can be said that the lower the sedimentation rate, the better the dispersing ability of the dispersant.

The evaluation results of cyanoethylated polyvinyl alcohol used in each Example and Comparative Example are summarized in Tables 1 and 2 below.

Inorganic analysis (ICP) Na(ppm) Example 1 <1 Example 2 <1 Comparative Example 1 120 Reference example 1 <1

Particle size (㎛) sedimentation rate
(μm/s) Dx(10) Dx(50) Dx(90) Example 3 0.83 1.74 3.69 6.26 Example 4 1.13 2.89 5.64 10.5 Comparative Example 2 1.16 3.08 5.98 11.26 Comparative Example 3 1.45 4.94 10.50 16.58

Referring to the results of Table 1, the 2-cyanoethyl group-containing polymer according to the embodiment of the present invention had a very low inorganic content of 1 ppm or less. In addition, since the present invention does not require a water washing process for removing inorganic salts in the purification/washing process, except for water used as a solvent for substitution reaction in the production of a 2-cyanoethyl group-containing polymer, the amount of water used can be minimized. . However, in Comparative Example 1, as the inorganic component was 120 ppm, several purification processes and a large amount of water were required. In addition, Reference Example 1 used a general organic catalyst and the content of inorganic components was similar to that of Examples, but dispersibility was reduced when used as a dispersant.

That is, in Table 2, the polymers according to Examples 3 and 4 of the present invention have particle size values of Dx (10) (μm), Dx (50) (μm) and Dx (10) (μm), as well as sedimentation rates. Compared to Comparative Examples 3 and 4, it can be confirmed that all of them are relatively small and have excellent dispersibility.

On the other hand, Comparative Example 3 was similar to Example 4 in particle size and sedimentation rate, but had relatively low dispersibility. In addition, the 2-cyanoethyl group-containing polymer used in Comparative Example 3 had a large content of residual inorganic components, requiring a large amount of water in the purification/washing process. Therefore, the method of Comparative Example 3 was inefficient due to an increase in process cost.

In the case of Comparative Example 4, a 2-cyanoethyl group-containing polymer having a low inorganic component content was used, but the average particle size distribution was larger than that of Example and the sedimentation rate was high, so the dispersibility was very poor.

Therefore, the separator using the 2-cyanoethyl group-containing polymer provided by the method of the present invention as a dispersant exhibits thermal stability equivalent to or higher than that of conventional ones, and has improved dispersibility, which can firmly adhere to inorganic fillers when manufacturing non-aqueous electrolyte battery separators. characteristics can be provided.

Claims (10)

reacting acrylonitrile and a hydroxyl group-containing compound in an organic solvent in the presence of an organic catalyst including 1,1,3,3-tetramethylguanidine to form a crude product including a 2-cyanoethyl group-containing polymer; and
Extracting the crude product with an extraction solvent including an organic solvent to form a purified 2-cyanoethyl group-containing polymer,
A method for producing a 2-cyanoethyl group-containing polymer.
According to claim 1,
The step of forming a crude product including the 2-cyanoethyl group-containing polymer,
Injecting acrylonitrile into an aqueous solution containing a hydroxyl group-containing compound and introducing an organic catalyst containing 1,1,3,3-tetramethylguanidine to perform a first reaction; and
Including the step of introducing an organic solvent and performing a secondary reaction in a state where the temperature of the primary reaction mixture is lowered,
A method for producing a 2-cyanoethyl group-containing polymer.
According to claim 2,
The first reaction is a method for producing a 2-cyanoethyl group-containing polymer comprising the step of performing at a temperature of 60 to 80 ° C. for 30 minutes to 120 minutes.
According to claim 2,
The secondary reaction is a method for producing a 2-cyanoethyl group-containing polymer comprising the step of adding an organic solvent and performing for 30 minutes to 300 minutes in a state where the temperature of the primary reaction mixture is lowered to the range of 40 to 60 ° C.
According to claim 1,
The organic catalyst is used in an amount of 0.01 to 0.05 parts by weight based on 1 part by weight of the hydroxyl group-containing compound.
The method of claim 1, wherein the organic solvent includes at least one selected from the group consisting of isopropyl alcohol and acetone.
The method of claim 1, wherein the hydroxyl group-containing compound includes a polyvinyl alcohol-based polymer, and the 2-cyanoethyl group-containing polymer is cyanoethyl polyvinyl alcohol.
The method of claim 1, wherein the extraction solvent includes at least one organic solvent selected from the group consisting of isopropyl alcohol, acetone, n-butanol, ethanol, toluene, and methyl isobutyl ketone, and the extraction step is performed a plurality of times. A method for producing a 2-cyanoethyl group-containing polymer.
The method of claim 1, wherein the purified 2-cyanoethyl group-containing polymer has i) a weight average molecular weight of 250,000 to 400,000, ii) a PDI of 1.5 to 2.5, and iii) a cyanoethyl group substitution rate in the range of 60 to 80%. , Method for producing a 2-cyanoethyl group-containing polymer.
The method for preparing a 2-cyanoethyl group-containing polymer according to claim 1, wherein the purified 2-cyanoethyl group-containing polymer contains less than 3 ppm of residual metal salt.