KR20240001814A - Preparation method of polyvinylidene fluoride-based polymer particles having particle size with low PDI - Google Patents

Abstract

The present invention relates to a method for producing polyvinylidene fluoride-based polymer particles having a uniform particle size, specifically, the steps of obtaining a mixture containing vinylidene fluoride (VDF), a dispersion medium, and a polymerization initiator; Stirring the mixture at a first stirring speed of 350 rpm to 800 rpm and raising the temperature to a first temperature; And stirring the mixture at a second stirring speed below the first stirring speed and above 200 rpm and raising the temperature from the first temperature to a second temperature. will be.

Description

Method for producing polyvinylidene fluoride-based polymer particles having uniform particle size {Preparation method of polyvinylidene fluoride-based polymer particles having particle size with low PDI}

The present invention relates to a method for producing polyvinylidene fluoride-based polymer particles having a uniform particle size.

Fluorine-based polymers range from thermoplastics, elastomers, and plastomers to thermoplastic elastomers, and can be semi-crystalline or completely amorphous, making them attractive polymers that can be used in a variety of applications. In addition, fluorine-based plastics with high fluorine content exhibit high heat, chemical, aging and weathering resistance, excellent inertness to solvents, hydrocarbons, acids and alkalis, low surface energy (oil and water repellency), low dielectric constant, and low flame retardancy. Low refractive index and moisture absorption. Moreover, the presence of strong C-F bonds has a decisive influence on the high resistance to oxidation and hydrolytic stability. In addition, the presence of a strong C-F bond has a critical impact on high resistance to oxidation and hydrolytic stability.

Therefore, many applications can be found with these special polymers. In the building industry (paints and coatings resistant to UV and graffiti), petrochemical and automotive industries, aerospace and aviation (as seals, gaskets and O-rings for use at extreme temperatures in liquid hydrogen or hydrazine tanks in aerospace boosters) Despite their high price, these polymers are used in key areas of modern technology: elastomers), chemical engineering (high-performance membranes), optics (fiber-optic cores and cladding), fiber processing, masonry (especially coatings for old monuments) and microelectronics. and has achieved progress in many application fields.

Meanwhile, among fluorine-based polymers, polyvinylidene fluoride (PVDF)-based polymer, which mainly contains repeating units derived from vinylidene fluoride, is also widely used as a binder material for batteries such as lithium-ion secondary batteries. For example, Patent No. 10-2019-0067810 discloses a vinylidene fluoride copolymer used as a binder for batteries.

However, the binder material is mainly used to adhere the electrode active material to the current collector. In this process, when polyvinylidene fluoride-based polymer particles are melted and used, the process efficiency varies depending on the molecular weight and particle size, so the desired size and molecular weight cannot be controlled. It is very important to secure capable technology.

Meanwhile, as a method of polymerizing polymers, emulsion polymerization and suspension polymerization are widely used. In the case of emulsion polymerization, it is widely used as a useful method for producing particles with uniform particle size distribution, but the diameter of the polymer particles produced by this method is Nanoparticles less than 1 μm are manufactured, and the surfactant used to provide stability to the particles is adsorbed on the surface of the particles, which has the disadvantage of causing foaming or deterioration of the physical properties of the polymer.

On the other hand, in the case of suspension polymerization, monomers are dispersed by mechanical stirring and then polymerized using a polymerization initiator, and while polymer particles with an average diameter of 100 micrometers or more are produced, the polymer particle size produced is non-uniform, so the particle size is uniform. In order to obtain polymer particles, a method is used to separate the particles according to size using a classification device. However, when using this separation method, the process is complicated, the cost of the classification device is excessive, and productivity is lowered. has

Accordingly, the present inventors confirmed that the uniformity of particle size could be significantly increased by adjusting the process conditions of the polymerization reaction step by step in producing a polyvinylidene fluoride-based polymer through suspension polymerization, and completed the present invention.

Republic of Korea Patent Publication No. 10-2019-0067810

The purpose in terms of work is

The object is to provide a method for producing polyvinylidene fluoride-based polymer particles having a uniform particle size.

In order to achieve the above purpose,

In terms of work,

Stirring the mixture at a first stirring speed of 350 rpm to 800 rpm and raising the temperature to a first temperature; and

A method for producing polyvinylidene fluoride-based polymer particles is provided, including the step of stirring the mixture at a second stirring speed of less than the first stirring speed and more than 200 rpm and raising the temperature from the first temperature to the second temperature. .

The first stirring speed may be 350 rpm to 750 rpm.

The second stirring speed may be 250 rpm to 650 rpm.

The first temperature may be 25°C to 40°C.

The second temperature may be 40°C to 60°C.

The mixture may further include a stabilizer.

The mixture may further include a comonomer that forms a copolymer with the vinylidene fluoride (VDF).

On another note,

Stirring the mixture at a first stirring speed of 350 rpm to 800 rpm and raising the temperature to a first temperature; and

A method of improving particle size uniformity of polyvinylidene fluoride (PVDF), including the step of stirring the mixture at a second stirring speed of less than the first stirring speed and more than 200 rpm and raising the temperature from the first temperature to the second temperature. This is provided.

In another aspect,

Polyvinylidene fluoride-based polymer particles are provided, which are manufactured by the above manufacturing method and have a standard deviation of particle size of 10 to 60.

The weight average molecular weight of the polyvinylidene fluoride-based polymer particles may be 600,000 to 2,000,000.

In another aspect

A binder material containing polyvinylidene fluoride-based polymer particles prepared by the above manufacturing method is provided.

In another aspect

A secondary battery comprising the binder material is provided.

The method for producing polyvinylidene fluoride-based polymer particles of the present invention can produce polyvinylidene fluoride-based polymer particles of uniform size without changing physical properties by adjusting the process conditions of the polymerization reaction step by step.

Accordingly, the production method of the present invention can easily adjust the size of the polyvinylidene fluoride-based polymer particles to suit the physical properties required in various fields, and the polyvinylidene fluoride-based polymer particles produced by the above production method, especially The physical properties of the binder can be further improved by using it as a battery binder that requires polyvinylidene fluoride-based polymer particles with a uniform particle size.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

Hereinafter, preferred embodiments of the present invention will be described. However, the embodiments of the present invention may be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Additionally, the following examples are provided to more completely explain the present invention to those with average knowledge in the relevant technical field. Accordingly, the shapes and sizes of elements in the drawings may be exaggerated for clearer explanation, and elements indicated by the same symbol in the drawings are the same element. In addition, the same symbols are used throughout the drawings for parts that perform similar functions and actions. In addition, throughout the specification, “including” a certain element means that other elements may be further included, rather than excluding other elements, unless specifically stated to the contrary.

In terms of work,

Obtaining a mixture containing vinylidene fluoride (VDF), a dispersion medium, and a polymerization initiator;

Stirring the mixture at a first stirring speed of 350 rpm to 800 rpm and raising the temperature to a first temperature; and

A method for producing polyvinylidene fluoride-based polymer particles is provided, including the step of stirring the mixture at a second stirring speed of less than the first stirring speed and more than 200 rpm and raising the temperature from the first temperature to the second temperature. .

The method for producing polyvinylidene fluoride-based polymer particles of the present invention is characterized by manufacturing polyvinylidene fluoride-based polymer particles with controlled particle size uniformity by adjusting the process conditions of the polymerization reaction step by step. It has the advantage of being able to produce polyvinylidene fluoride-based polymer particles with significantly increased particle size uniformity without changing physical properties such as molecular weight, molecular weight uniformity, melting point, and decomposition temperature.

Here, the standard deviation of the particle size is defined as the ratio of the square root of the sum of the square deviations of the particle size to the average particle size, and means the distribution of the particle size. The lower the standard deviation of the particle size, the higher the uniformity of the particle size. do.

Hereinafter, the method for producing polyvinylidene fluoride-based polymer particles according to an embodiment will be described in detail in each step.

A method for producing polyvinylidene fluoride-based polymer particles according to an embodiment includes obtaining a mixture containing vinylidene fluoride (VDF), a dispersion medium, and a polymerization initiator.

The mixture may contain materials necessary for producing polyvinylidene fluoride-based polymer particles.

The mixture includes a dispersion medium, which is a medium for dispersing the vinylidene fluoride (VDF), and for example, distilled water may be used.

The mixture includes a polymerization initiator, and the polymerization initiator includes diisopropyl peroxydicarbonate, dinormal propyl peroxydicarbonate, dinormal heptafluoropropyl peroxydicarbonate, diisopropyl peroxydicarbonate, and isobutyryl peroxydicarbonate. Oxide, di(chlorofluoroacyl)peroxide, di(perfluoroacyl)peroxide, etc. may be used, but are not limited thereto, and other known polymerization initiators that polymerize polyvinylidene fluoride-based polymers may be used. .

Meanwhile, the polymerization initiator may preferably have an initiation temperature of 40°C to 60°C. For example, diisopropyl peroxydicarbonate (DIPPDC) may be used.

If the starting temperature of the polymerization initiator is a high temperature exceeding 60°C, the gas pressure may become excessively high, which may not only be dangerous but also difficult to control the reaction rate, and if the starting temperature of the polymerization initiator is a low temperature of less than 40°C. , management may be difficult due to poor storage stability.

The polymerization initiator may be included in the mixture in an amount of 0.01% to 5% by weight.

If the polymerization initiator is contained in less than 0.01% by weight, the polymerization reaction may not proceed sufficiently, and if it exceeds 5% by weight, a problem may arise in which a polymer with an uneven molecular weight is produced.

The mixture includes a reactant, and the reactant includes vinylidene fluoride (VDF), and when preparing a copolymer, it may further include a comonomer. The comonomers that can be used at this time are Acrylic acid, Maleic acid, Maleic anhydride, Methacrylic acid, 3-sulfopropyl methacrylate, 2-Cyanoethyl acrylate, vinylsulfonic acid, glycidyl methacrylate, hydroxyethylmethacrylate, etc. may be used, but are not limited to these. Other monomers capable of forming copolymers with vinylidene fluoride (VDF) may be used.

The mixture may further include a stabilizer, and the stabilizer includes methylcellulose, methoxylated methylcellulose, propoxylated methylcellulose, hydroxyethyl cellulose, hydroxypropylmethylcellulose, hydroxypropyl cellulose, polyvinyl alcohol, and polyethylene oxide. , gelatin, etc. may be used, but are not limited thereto, and other known suspension stabilizers that can be used for suspension polymerization of polyvinylidene fluoride-based polymers may be used.

The stabilizer may be included in the mixture in an amount of 0.01% to 5% by weight.

As an example, the step of obtaining the mixture may be performed by adding a stabilizer, a dispersion medium, and an initiator, stirring to uniformly mix, and adding the reactant.

A method for producing polyvinylidene fluoride-based polymer particles according to an embodiment includes stirring the mixture at a first stirring speed of 350 rpm to 800 rpm and raising the temperature to a first temperature.

This step may be a particle formation step in which polymer particles begin to be generated.

In the conventional case, the temperature is raised from the temperature at which polymerization starts to the temperature at which polymerization ends without changing the stirring speed during the polymerization reaction, and polymerization is performed while stirring at the same speed. However, in the case of the polyvinylidene fluoride-based polymer particles according to one embodiment, The manufacturing method is characterized by manufacturing polymer particles with significantly increased particle size uniformity by varying the temperature and stirring speed in the polymer particle forming stage and the polymer particle growing stage.

At this time, the first temperature is a temperature at which polymerization can be initiated, and may preferably be 25°C to 40°C, and more preferably 25°C to 35°C.

The particle formation step is performed by stirring the mixture at a first stirring speed of 350 rpm to 800 rpm and raising the temperature to the first temperature.

In order to form polymer particles with a low standard deviation of particle size, it is preferable to stir at a speed of 350 rpm or more in the particle forming step, preferably 350 rpm to 800 rpm, more preferably 350 rpm to 750 rpm, and more preferably 450 rpm to 700 rpm. , more preferably stirring at a speed of 550 rpm to 650 rpm.

If the first stirring speed is lowered to less than 350 rpm in the particle formation step, polymer particles having a non-uniform particle size and a large standard deviation of the particle size can be produced.

The particle forming step may be performed for 5 to 60 minutes.

The particle formation step may be performed at a pressure of 10 bar to 40 bar.

A method for producing polyvinylidene fluoride-based polymer particles according to an embodiment includes stirring the mixture at a second stirring speed of less than the first stirring speed and more than 200 rpm and raising the temperature from the first temperature to the second temperature. do.

The step may be a particle growth step in which the produced polymer particles grow.

In the step, the temperature is increased from the first temperature at which polymerization is initiated to a second temperature at which particle growth occurs, and the second temperature is preferably 40°C to 60°C, and more preferably 45 to 55°C. there is.

In the particle growth step, the mixture is stirred at a stirring speed lower than that of the particle forming step (first stirring speed) and a second stirring speed of 200 rpm or higher, and the mixture is heated to a second temperature.

In order to form polymer particles with a low standard deviation of particle size, in the particle growth step, it is preferable to stir at a speed of less than the first stirring speed, preferably less than the first stirring speed, and preferably 200 rpm or more.

Accordingly, the second stirring speed is preferably 200 rpm to 800 rpm, preferably 250 rpm to 650 rpm, more preferably 250 rpm to 550 rpm, and more preferably 250 rpm to 350 rpm.

If, in the particle growth step, the second stirring speed is greater than the first stirring speed or lowered to less than 200 rpm, polymer particles having a non-uniform particle size and a relatively large standard deviation of the particle size can be produced.

In addition, in order to form polymer particles having a uniform size, the difference between the first and second stirring speeds may be 0 to 400, preferably 50 to 350, 150 to 350, and 250. It may be from 350 to 350.

The particle growth step may further include adding vinylidene fluoride (VDF) to the mixture under the second temperature and second stirring speed conditions.

The particle growth step may be performed for 1 hour to 24 hours.

The particle growth step may be performed at a pressure of 30 bar to 70 bar, and may preferably be performed at a relatively higher temperature and pressure than the particle formation step.

The method for producing polyvinylidene fluoride-based polymer particles according to an embodiment may further include maintaining the second temperature and a constant pressure of 30 bar to 70 bar after the particle growth step, wherein the constant temperature and Additional vinylidene fluoride (VDF) can be supplied to maintain pressure.

As described above, the method for producing polyvinylidene fluoride-based polymer particles according to an embodiment is to adjust the stirring speed step by step in the particle formation step and particle growth step during the polymerization reaction, thereby adjusting the molecular weight, molecular weight uniformity, melting point, Polyvinylidene fluoride-based polymer particles with a low standard deviation of particle size can be manufactured without changing physical properties such as decomposition temperature.

The method for producing polyvinylidene fluoride-based polymer particles according to an embodiment is to produce polyvinylidene fluoride-based polymer particles with a standard deviation of particle size of 10 to 60, 15 to 40, 15 to 35, and 15 to 25. can do.

At this time, the weight average molecular weight of the polyvinylidene fluoride-based polymer particles may be 600,000 to 2,000,000, and the polymer particles may have a size of 10 μm to 500 μm.

On the other side

Obtaining a mixture containing vinylidene fluoride (VDF), a dispersion medium, and a polymerization initiator;

Stirring the mixture at a first stirring speed of 350 rpm to 800 rpm and raising the temperature to a first temperature; and

A method of improving particle size uniformity of polyvinylidene fluoride (PVDF), including the step of stirring the mixture at a second stirring speed of less than the first stirring speed and more than 200 rpm and raising the temperature from the first temperature to the second temperature. This is provided.

A method for improving particle size uniformity of polyvinylidene fluoride (PVDF) according to an embodiment may include part or all of the method for producing polyvinylidene fluoride-based polymer particles described above.

A method for improving the particle size uniformity of polyvinylidene fluoride (PVDF) according to an embodiment is to adjust the stirring speed in the polymerization reaction step by step when manufacturing polyvinylidene fluoride-based polymer particles, thereby improving molecular weight, molecular weight uniformity, and melting point. , polyvinylidene fluoride-based polymer particles with improved particle size uniformity with a standard deviation of particle size of 10 to 60, 15 to 40, 15 to 35, and 15 to 25 can be produced without changing physical properties such as decomposition temperature. .

In another aspect

Polyvinylidene fluoride-based polymer particles are provided, which are manufactured by the above manufacturing method and have a standard deviation of particle size of 10 to 60.

At this time, the weight average molecular weight of the polyvinylidene fluoride-based polymer particles may be 600,000 to 2,000,000.

In another aspect

A binder material containing polyvinylidene fluoride-based polymer particles prepared by the above manufacturing method is provided.

In another aspect

A secondary battery containing the binder material is provided.

Polyvinylidene fluoride-based polymer particles manufactured by the manufacturing method according to an embodiment can have uniform molecular weight and particle size, thereby improving binder properties, and further improving the characteristics of secondary batteries containing the binder. It can be improved.

Hereinafter, the present invention will be described in detail through examples and experimental examples.

However, the following examples and experimental examples only illustrate the present invention, and the content of the present invention is not limited to the following examples.

<Example 1>

Step 1: Into an autoclave reactor with a capacity of 1 liter, 520 g of distilled water containing 1 g of hydroxypropyl methyl cellulose (HPMC) as a suspension stabilizer and 1 g of diisopropyl peroxydicarbonate (DIPPDC) as an initiator were added. Afterwards, a nitrogen atmosphere was created through a process of removing the internal air using a vacuum pump and nitrogen and replacing it with nitrogen. Afterwards, 200 g of VDF as a reactant and 1 mol % of acrylic acid as a copolymer were added.

Step 2: The material in the reactor into which the reactant was added was stirred at 400 rpm (first stirring speed) and reacted while heating at a temperature increase rate of 0.4°C/min to 30°C, which is the temperature at which VDF reaches the supercritical state.

Step 3: Afterwards, the material in the reactor was stirred at 300 rpm (second stirring speed) and the temperature was raised to 50° C. at a temperature increase rate of 0.4° C./min. Afterwards, VDF was additionally supplied to maintain the temperature and pressure in the reactor constant at 50°C and 60 bar.

Step 4: The reaction was terminated 24 hours after the start of the reaction, filtered with distilled water, and dried in a vacuum oven for more than 24 hours to obtain polymer particles.

<Example 2>

Polymer particles were obtained in the same manner as in Example 1, except that in step 2 of Example 1, the first stirring speed was changed to 500 rpm.

<Example 3>

Polymer particles were obtained in the same manner as in Example 1, except that in step 2 of Example 1, the first stirring speed was changed to 600 rpm.

<Example 4>

Polymer particles were obtained by performing the same method as in Example 1, except that the first stirring speed was changed to 600 rpm in step 2 of Example 1, and the second stirring speed was changed to 400 rpm in step 3.

<Example 5>

Polymer particles were obtained by performing the same method as in Example 1, except that the first stirring speed was changed to 600 rpm in step 2 of Example 1, and the second stirring speed was changed to 600 rpm in step 3.

<Comparative example 1>

Step 1: Into an autoclave reactor with a capacity of 1 liter, 520 g of distilled water containing 1 g of hydroxypropyl methyl cellulose (HPMC) as a suspension stabilizer and 1 g of diisopropyl peroxydicarbonate (DIPPDC) as an initiator were added. Afterwards, a nitrogen atmosphere was created through a process of removing the internal air using a vacuum pump and nitrogen and replacing it with nitrogen. Afterwards, 200 g of VDF as a reactant and 1 mol % of acrylic acid as a copolymer were added.

Step 2: The material in the reactor into which the reactant was added was stirred at 300 rpm and the temperature was raised to 50°C at a temperature increase rate of 0.4°C/min. Afterwards, VDF was additionally supplied to keep the temperature and pressure in the reactor constant.

Step 3: The reaction was terminated 24 hours after the start of the reaction, filtered with distilled water, and dried in a vacuum oven for more than 24 hours to obtain polymer particles.

<Comparative example 2>

Polymer particles were obtained by performing the same method as in Example 1, except that the first stirring speed was changed to 600 rpm in step 2 of Example 1, and the second stirring speed was changed to 150 rpm in step 3.

<Comparative example 3>

Polymer particles were obtained by performing the same method as in Example 1, except that the first stirring speed was changed to 300 rpm in step 2 of Example 1, and the second stirring speed was changed to 600 rpm in step 3.

The process conditions of Examples 1 to 5 and Comparative Examples 1 to 3 are shown in Tables 1 and 2 below.

Example 1 Example 2 Example 3 Example 4 Example 5 DI Water (g) 520 520 520 520 520 DIPPDC (g) One One One One One HPMC (g) One One One One One VDF (g) 200 200 200 200 200 Acrylic acid (g) One One One One One Stirring speed A (rpm, RT ~30℃) 400 500 600 600 600 Stirring speed B (rpm, 30℃ ~ 50℃) 300 300 300 400 600 reaction time (h) 24 24 24 24 24

Comparative Example 1 Comparative Example 2 Comparative Example 3 DI Water (g) 520 520 520 DIPPDC (g) One One One HPMC (g) One One One VDF (g) 200 200 200 Acrylic acid (g) One One One Stirring speed A (rpm, RT ~30℃) 300 600 300 Stirring speed B (rpm, 30℃ ~ 50℃) 300 150 600 reaction time (h) 24 24 24

<Experiment Example 1>

The molecular weight, particle size, polydispersity index (PDI) of the molecular weight, standard deviation of the particle size, melting point (T _m ), and weight loss of 5% of the polymer particles prepared in Examples 1 to 5 and Comparative Examples 1 to 3 The decomposition temperature (T _d ) was measured and the results are shown in Tables 3 and 4 below.

At this time, the molecular weight of the polymer particles is evaluated using gel permeation chromatography (GCP), the particle size is evaluated using a particle size analyzer (PSA), and the polydispersity index (PDI) of the molecular weight is evaluated. , the standard deviation of particle size was calculated using the formula below, the melting point (T _m ) was measured by Differential Scanning Calorimetry (DSC), and the decomposition temperature (T _d ) was measured by thermogravimetric analysis (TGA). It was measured.

Polydispersity index (PDI) of molecular weight = weight average molecular weight/number average molecular weight

Standard deviation of particle size = square root of sum of squared particle size deviations/average particle size

Example 1 Example 2 Example 3 Example 4 Example 5 Molecular weight (Mw) / PDI 1292k / 2.0 1241k / 2.0 1267k / 2.0 1227k / 2.0 1149k / 2.0 Particle size (μm) / standard deviation 205.6 / 49.0 215.3 / 36.4 208.8 / 20.1 155.5 / 38.4 129.9 / 30.2 Melting point (℃) 169.7 170.4 170.5 170.2 169.9 5% decomposition temperature (T _d ) 488.1 490.6 487.0 496.4 445.4

(k in molecular weight means 1000)

Comparative Example 1 Comparative Example 2 Comparative Example 3 Molecular weight (Mw) / PDI 1246k / 2.3 1036k / 2.8 1044k / 2.5 Particle size (μm) / standard deviation 192.4 / 107.9 322.8 / 97.8 168.4 / 75.8 Melting point (℃) 169.9 171.8 169.9 5% decomposition temperature (T _d ) 449.3 435.7 467.5

(k in molecular weight means 1000)

As shown in Tables 3 and 4, Examples 1 to 5 and Comparative Examples 1 to 3 have a molecular weight of 1000k to 1300k, a melting point of 169°C to 172°C, and a decomposition temperature of 440°C to 500°C, 2 The physical properties are similar in that they have a molecular weight with a low polydispersity index of 3 to 3, but in terms of the standard deviation of particle size, Comparative Examples 1 to 3 produced polymer particles of non-uniform size with a high value of 97 to 108. On the other hand, it can be confirmed that Examples 1 to 5 produced polymer particles of uniform size with significantly low values of 20 to 50.

Based on the above results, during the polymerization reaction, in the particle formation stage where the mixture becomes hypercritical and polymer particles are formed, the temperature is raised to 25°C to 40°C while stirring at a relatively high speed of 350 rpm to 800 rpm, and then for particle growth. By raising the temperature to 40°C to 60°C by stirring at a stirring speed below and above 200 rpm in the particle formation step, polymer particles with a significantly low standard deviation of particle size can be manufactured, while particle formation as in Comparative Example 1 If the stirring speed in the step is as low as 300 rpm, as in Comparative Example 2, and if it is too low as less than 200 rpm in the particle growth step even though stirring is done at a relatively high speed of 350 rpm to 800 rpm in the particle formation step, as in Comparative Example 3, and in the particle formation step as in Comparative Example 3 When the stirring speed is increased in the entry step, it can be seen that the standard deviation of the particle size is 75 or more, forming particles of non-uniform size.

In addition, the above results confirm that polymer particles of uniform size can be manufactured by adjusting the process conditions of the polymerization reaction for producing polyvinylidene fluoride-based polymer particles step by step as in Examples 1 to 5. You can.

Claims (12)

Obtaining a mixture containing vinylidene fluoride (VDF), a dispersion medium, and a polymerization initiator;
Stirring the mixture at a first stirring speed of 350 rpm to 800 rpm and raising the temperature to a first temperature; and
A method for producing polyvinylidene fluoride-based polymer particles, comprising: stirring the mixture at a second stirring speed of less than the first stirring speed and more than 200 rpm and raising the temperature from the first temperature to the second temperature.
According to paragraph 1,
A method for producing polyvinylidene fluoride-based polymer particles, wherein the first stirring speed is 350 rpm to 750 rpm.
According to paragraph 2,
A method for producing polyvinylidene fluoride-based polymer particles, wherein the second stirring speed is 250 rpm to 650 rpm.
According to paragraph 3,
A method for producing polyvinylidene fluoride-based polymer particles, wherein the first temperature is 25°C to 40°C.
According to clause 4,
A method for producing polyvinylidene fluoride-based polymer particles, wherein the second temperature is 40°C to 60°C.
According to paragraph 1,
A method for producing polyvinylidene fluoride (PVDF), wherein the mixture further includes a stabilizer.
According to paragraph 1,
The mixture further includes a comonomer that forms a copolymer with the vinylidene fluoride (VDF).
Obtaining a mixture containing vinylidene fluoride (VDF), a dispersion medium, and a polymerization initiator;
Stirring the mixture at a first stirring speed of 350 rpm to 800 rpm and raising the temperature to a first temperature; and
A method of improving particle size uniformity of polyvinylidene fluoride (PVDF), including the step of stirring the mixture at a second stirring speed of less than the first stirring speed and more than 200 rpm and raising the temperature from the first temperature to the second temperature. .
Polyvinylidene fluoride-based polymer particles manufactured by the manufacturing method of claim 1 and having a standard deviation of particle size of 10 to 60.
According to clause 9,
The polyvinylidene fluoride-based polymer particles have a weight average molecular weight of 600,000 to 2,000,000.
A binder material comprising polyvinylidene fluoride-based polymer particles manufactured by the manufacturing method of claim 1.
A secondary battery comprising the binder material of claim 11.