KR20090123894A - Non―woven fabric reinforced microporous polymer membrane,manufacturing method and use thereof - Google Patents

Abstract

A non-woven fabric reinforced microporous polymer membrane for nonaqueous electrolyte batteries or capacitor and manufacturing method thereof. The polymer latex is prepared by copolymerizing water soluble polymer 100 parts, hydrophobic monomer 30-500 parts, hydrophilic monomer 0-200 parts and initiator 1-5 parts. According to 100% solids content of the polymer latex, adding 0-100% inorganic fillers and 20-100% plasticizers, and the paste is obtained. The two surface of the non-woven fabric are coated with the paste, drying, and the non-woven fabric reinforced microporous polymer membrane is obtained.

Description

Microporous reinforced nonwoven polymer membrane, manufacturing method and use {NON-WOVEN FABRIC REINFORCED MICROPOROUS POLYMER MEMBRANE, MANUFACTURING METHOD AND USE THEREOF}

The present invention relates to a diaphragm material for an electric device such as a nonaqueous electrolyte battery and a method of manufacturing the same, and to a field of manufacturing an electric device such as a battery and a capacitor.

Microporous polymer membranes are one of the three essential materials for the production of non-aqueous electrolyte electric devices such as lithium ion batteries, metal lithium secondary batteries, super capacitors, and the like. To ensure the isolation of the negative electrode, the material properties, microporous structure, and physicochemical properties used in the microporous polymer membrane are closely related to the electrical performance, safety, and cycle life of the lithium ion battery. Separators used in non-aqueous electrolyte electric devices that are already commercialized are mainly microporous polyolefin membranes, microporous polyvinylidene fluoride (polyvinyllidene fluoride), and microporous polyolefin / polyvinylidene composite membranes.

The microporous polyolefin membrane includes a polybutylene / polypropylene / polybutylene propylene composite membrane and is manufactured by mechanical two-way stretch (dry method) and solvent extraction method (wet method). Polyolefin is a non-polar material, incompatible with the polar organic solvent in the electrolyte solution, only serves as a mechanical isolation between the positive and negative electrodes in the battery, there is no affinity with the electrolyte solution, so that the electrolyte is present in the battery in the glass state, The electrolyte released during the charge / discharge cycle of the battery inevitably causes a redox side reaction with the positive / cathode material and consumes the electrolyte in the battery, resulting in a lack of electrolyte in the battery, thereby increasing the polarization of the battery and causing lithium ions to be lithium metal. Lithium deposition crystals are produced by the reduction, and thus lithium dendritic crystals are generated, resulting in separator puncture. Crystalline zones and lithium dendritic crystals due to battery electrolyte deficiency easily cause electrostatic breakdown and direct short-circuit between positive and negative electrodes, leading to safety problems such as combustion and explosion of lithium ion batteries. The safety problem of lithium ion batteries has limited the power generation area in the use of lithium ion batteries as a large capacity, high power powered power source.

Polyvinylidene (PVDF) and its derivatives can form membranes only under the presence of plasticizers. PVDF membranes containing plasticizers have excellent self adhesiveness, low mechanical strength, and low workability, and thus cannot form microporous polymer membranes alone. The method of manufacturing such a microporous polymer membrane is basically a battery cell by joining a PVDF membrane containing a plasticizer and a battery positive electrode pole piece by thermal bonding method, and then manufacturing a battery cell, and then using an organic solvent to extract the positive electrode This composite PVDF microporous polymer film is formed. In order to solve the technical difficulties in the production of PVDF microporous polymer membranes, a film is formed solely like a microporous polyolefin, and a PVDF solution is applied to the microporous polyolefin membrane to improve the operability of battery manufacturing, and then solvent extraction method or phase inversion. (Phase-inversion Technique) A microporous polyolefin / polyvinylidene composite membrane is prepared by a membrane production method.

Disadvantages of the microporous polyolefin membrane, the microporous polyvinylidene fluoride membrane, and the microporous polyolefin / polyvinylidene composite membrane have low heat resistance, so that when the battery's internal temperature exceeds 150 ° C, the polyolefin material is fused and the micropores are lost, thereby reducing ion conductivity. Blocking, or so-called melt protection, occurs, but when the microporous polymer membrane is melted, it causes a large volume reduction and a reduction in membrane area, which is likely to cause a direct short circuit between the positive and negative electrodes inside the battery. May result.

In order to overcome the heat resistance problem of the microporous polyolefin membrane, DEGUSSA of Germany produced an inorganic ceramic porous membrane (CN1735983A) using a high-polymer nonwoven fabric as a support, by reducing the shrinkage of the separator under high temperature and improving battery safety. The nonwoven support used a large amount of inorganic filler, and this filler was composited with the nonwoven by a silane adhesive. The inorganic membrane improves the heat resistance of the separator and reduces the shrinkage of the separator under high temperature. However, in the composite method, powder dropout occurs due to vibration, warpage, and folding during drying and use of the membrane, so that the coating layer of the membrane is not flat and the local voltage is increased due to uneven distribution of current during charging and discharging of the battery. It can lead to destruction.

At present, there is an urgent need for microporous polymer membranes used in lithium ion batteries and metal lithium batteries, and these polymer membranes can block ion conduction even at high temperatures, and large changes can occur due to the size of the separator. In this case, it is desirable to ensure good isolation between the battery cathodes, to ensure the safety of the battery, and to have a low price.

According to a conventional study by the inventor of the present invention (ZL0113373.0), after mixing a polyacrylonitrile colloid emulsion with EVA (ethylene-vinyl acetate copolymer) methylbenzene solution using an acrylonitrile monomer, the polymer colloid emulsion The microporous polymer membrane formed by maintaining the condensation of the polyacrylonitrile colloidal particles can be obtained by forming a membrane by flowing a stream. The membrane can maintain a stable geometric size even at relatively high temperatures (above 150 ° C.) so that large shrinkage of volume and area does not occur. In addition, the polymer electrolyte membrane formed after absorbing the electrolyte solution may block the ionic conduction by melting the EVA component in the temperature range of 70 ~ 90 ℃, thereby changing the polymer electrolyte membrane into an insulating film having no ion conductivity. Lithium ion batteries prepared using the membranes have superior safety reliability. In addition, the cyano group (-CN) and the ester group (-COO-) in the microporous polymer membrane have good affinity for the electrolyte, and thus the lithium ion battery produced has good battery charge and discharge and cycle life. The high safety and good cell performance of the membrane is due to the specific particle microporous structure, chemical composition and performance of the membrane. However, the membrane uses EVA as an adhesive between the polyacrylonitrile colloid particles, and the mechanical strength of the membrane is relatively low due to the low EVA thermal softening temperature and the mechanical strength, and there are many difficulties in the battery manufacturing process. In addition, since methylbenzene is used as a reaction medium in preparing a polyacrylonitrile colloid, there is a serious environmental pollution problem in the membrane manufacturing process.

The inventor of the present invention improves on the technique of ZL01133737.0 and proves that even after changing the polymer composition of the membrane through a number of experiments, it is possible to synthesize a polymer colloidal emulsion containing a polar monomer of acrylonitrile using water as a medium. did. The microporous polymer membrane prepared by the aqueous polymer colloidal emulsion has the advantage that the polyacrylonitrile microporous polymer membrane prepared by the methylbenzene solvent is possessed and has the advantage of improving the softening point temperature and the mechanical strength of the microporous polymer membrane. The method of avoiding the environmental pollution problem in the film formation process using water as the reaction medium is a clean and environmentally friendly microporous polymer membrane manufacturing process technology. Conventional microporous polymer membranes, including hydrophilic groups, are relatively sensitive to humidity in the environment. Therefore, since the change in the size of the film occurs under high humidity, it is difficult to control the process in manufacturing the battery.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a separator, that is, a microporous reinforced nonwoven polymer membrane, which is applied to an electric device such as a lithium ion battery, a metal lithium secondary battery, and a super capacitor using a nonaqueous electrolyte as an ion conducting medium. The separator solves the problems existing therein based on the microporous polymer membrane prepared from ZL01133737.0 and an aqueous polymer colloidal emulsion, thereby providing higher heat resistance and mechanical strength to electrical devices such as lithium ion batteries, metal lithium secondary batteries, and supercapacitors. By providing a low-cost microporous polymer membrane has a better safety and a long cycle life.

The microporous reinforced nonwoven polymer separator according to the present invention copolymerizes 100 parts by weight of a water-soluble polymer, 30 to 500 parts by weight of hydrophobic monomer, 0 to 200 parts by weight of hydrophilic monomer, and 1 to 5 parts by weight of an initiator to prepare a polymer colloidal emulsion. Based on the solids content of the prepared polymer colloidal emulsion to 100%, characterized in that it is prepared by coating and drying the sized agent obtained by adding 0 to 100% of inorganic filler, 20 to 100% of a plasticizer on both sides of the nonwoven fabric.

The nonwoven fabric is characterized in that it is a kind of nonwoven fabric made of polyacrylonitrile, nylon, polyvinyl foam, polyolefin or polyester fibers.

The water-soluble polymer is a polyvinyl alcohol, polyoxyethylene, polyvinylpyrrolidone or polyvinylpyrrolidone water-soluble copolymer, the degree of polymerization of the polyvinyl alcohol is 1700 ~ 2400 and the degree of hydrolysis is 50 ~ 99, the polyoxy The molecular weight of ethylene is 100,000 to 2 million, and the molecular weight of the polyvinylpyrrolidone or polyvinylpyrrolidone water-soluble copolymer is 500 to 100,000, preferably 10,000 to 30,000;

The hydrophobic monomer is at least one of the hydrophobic monomer represented by the formula (1):

CH ₂ = CR ¹ R ²

In Chemical Formula 1,

R ¹ is -H or -CH ₃ ,

R ² is -C ₆ H ₅ , -OCOCH ₃ , -COOCH ₃ , -COOCH ₂ CH ₃ , -COOCH ₂ CH ₂ CH ₂ CH ₃ , -COOCH ₂ CH (CH ₂ CH ₃ ) CH ₂ CH ₂ CH ₂ CH ₃ or -CN;

The hydrophilic monomer is at least one of the hydrophilic monomers represented by the following formula (2):

CHR ³ = CR ⁴ R ⁵

In Chemical Formula 2,

R ³ is -H, -CH ₃ or -COOLi,

R ⁴ is -H, -CH ₃ or -COOLi,

R ⁵ is -COOLi, -CH ₂ COOLi, -COO (CH ₂ ) ₆ SO ₃ Li, -CONH ₂ , -CONHCH ₃ , , -CONHCH ₂ CH ₃ , -CON (CH ₃ ) ₂ or -CON (CH ₂ CH ₃ ) ₂ .

The initiator may be ammonium persulfate, potassium persulfate, hydrogen peroxide or 2,2'-azobis (2-methyl propionamidine dihydrochloride) (2,2'-azobis (2-methyl propionamidine dihydrochloride)), or the The compound is characterized in that the redox initiator comprising Na ₂ SO ₃ or FeSO ₄ .

The plasticizer is characterized in that at least one of propanediol, benzyl alcohol, normal butyl alcohol, isopropanol, triethyl phosphoric acid, diethyl phosphoric acid, trimethyl phosphoric acid, tributyl phosphoric acid.

In order to improve the heat resistance, porosity and membrane stiffness of the microporous polymer, an inorganic filler is added to the aqueous polymer colloidal emulsion. The inorganic filler typically uses fine powder and has a high specific surface area and strong surface adsorption force, thereby improving adsorption of electrolyte solution and separation of electrolyte salt and improving ion conductivity of the membrane. The inorganic filler is characterized in that carbon white, aluminum oxide, titanium dioxide, germanium oxide, magnesium oxide, calcium carbonate or glass fiber by gas chromatography.

In order to improve the dispersibility of the inorganic filler in the polymer colloidal emulsion, a silane binder may be added, and the silane binder may be 3-aminopropyltriethoxysilane, 2-aminoethyl-3-aminopropyltrimethoxy silane, 3-epihydrin alcoholtrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, or vinyltri (2-methoxyethoxy) silane, and the amount of the silane binder added is 0.5-by weight of the inorganic filler. 5.0%.

In order to improve the safety of the microporous reinforced nonwoven polymer membrane, the organic filler is added to enhance the ion conduction blocking property of the membrane, thereby allowing the battery of the microporous reinforced nonwoven polymer membrane to block the continuous flow of cations in the range of 100 to 130 ° C. If the temperature is out of limits, the safety of the battery can be guaranteed. The organic filler is one of polyethylene powder, polyethylene wax powder and polyethylene oxide wax powder. The amount of the organic filler added is 5.0 to 20% based on the solids content in the polymer colloidal emulsion at 100%.

Another technical problem to be solved by the present invention is to provide an environmentally friendly microporous reinforced nonwoven polymer membrane manufacturing technology and at the same time reduce the production cost of the microporous polymer and to provide a low-cost and good performance microporous polymer membrane for the production of non-aqueous electrolyte electronic device It is.

The method for producing the nonwoven fabric-reinforced microporous polymer membrane provided by the present invention includes the following steps.

(a) 100 parts by weight of water-soluble polymer and 0 to 200 parts by weight of hydrophilic monomer are added with water until heated to dissolve, and the mixture is stirred until it is dissolved. Adding to the reactor several times or several times or in a dropwise manner and adding 1 to 5 parts by weight of an initiator to polymerize for 4 to 35 hours to prepare a polymer colloidal emulsion;

(b) a size obtained by adding 0-100% of an inorganic filler and 20-100% of a plasticizer to the polymer colloidal emulsion based on 100% of the solid content of the polymer colloidal emulsion, followed by uniformly stirring and polishing for 2-10 hours. Preparing a polymeric colloidal sized agent by removing large granular material that is not polished using a screen having a pore size of 200 or less; And

(c) uniformly coating and drying the water-soluble polymer colloid sized agent on both sides of the nonwoven fabric to prepare a microporous reinforced nonwoven polymer separator.

The nonwoven fabric is one of nonwoven fabrics made of polyacrylonitrile, nylon, polyvinyl foam, polyolefin or polyester fiber, the thickness of the nonwoven fabric is 50 µm or less, the void is 40% or more, and the pore diameter is 5 to 200. Μm, and the weight per area of the nonwoven fabric is 25 g / m ² or less.

In order to improve the safety of the microporous reinforced nonwoven polymer membrane, the organic filler is added to enhance the ion conduction blocking property of the membrane, thereby allowing the battery of the microporous reinforced nonwoven polymer membrane to block the continuous flow of cations in the range of 100 to 130 ° C. If the temperature is out of limits, the safety of the battery can be guaranteed. The organic filler is one of polyethylene powder, polyethylene wax powder and polyethylene oxide wax powder.

In addition, another technical problem to be solved by the present invention is to utilize a microporous reinforced nonwoven polymer membrane in the production of a lithium ion battery, a super capacitor or a battery / super capacitor.

The microporous reinforced nonwoven polymer membrane according to the present invention is a polymer compound main material containing a group having high polarity (for example, -CN, -COO-, -NH ₂ , -O-, etc.), and has good solubility with a nonaqueous electrolyte. In addition to forming a polymer colloid, the super solvent of the polar group and the nonaqueous electrolyte exerts a chemical bonding effect, so that the electrolyte in the battery exhibits solid properties and the separator maintains a good wet state.

Nonwoven fabrics improve the strength, flexibility and heat resistance of the membrane in the microporous polymer membrane, reduce the problem that the hydrophilic polymer component causes the membrane size change due to ambient humidity, and improve the reliability and stability in the battery manufacturing process.

Hereinafter, specific examples of the microporous reinforced nonwoven polymer membrane of the present invention will be described in detail.

In general, under the same porosity and flexibility conditions, the larger the porosity of the microporous polymer membrane, the smaller the resistance generated by the electrolyte-impregnated separator. The Gurley- number of microporous polymer membranes is a measure of the breathability of dry porous membranes. As O.besenhard mentioned in the "handbook of Battery Materials", the ion conductivity of existing systems can be estimated directly from Gurley-water. In general, high breathability (i.e., relatively small Gurley-number) is known to cause the separator impregnated with the electrolytic electrolyte to generate a relatively high conductivity. It should be noted, however, that very low Gurley-number may indicate a defect in the separator. That is, when large pores exist in the microporous polymer membrane, such pores may cause an internal short circuit when working with an electric device. In this case, the electric element causes a dangerous reaction such as an emergency self discharge, at which time a relatively large current is generated to generate a large amount of heat therein, and in a severe case, the sealed electric element causes an explosion accident. For this reason, the separator plays a decisive role in the safety of lithium ion batteries and metal lithium secondary batteries. Therefore, the microporous polymer membrane is a critical component that requires great attention in an electric device. Suitable ranges of Gurley numbers are 5 to 200, and in the prior art Gurley numbers are generally 10 to 50. In order to more directly express the microporous state of the microporous reinforced nonwoven polymer membrane, the embodiment of the present invention shows that the membrane permeability and conductivity are based on the air permeability of the microporous polymer membrane.

1. Preparation of Aqueous Polymer Colloid Latex

The present invention provides a polymer colloidal emulsion by performing a graft copolymerization using an initiator in a solution containing water as a reaction medium, a hydrophobic monomer, and a hydrophilic monomer (if employed) using a water-soluble polymer. .

Specific manufacturing method: a. Heating and stirring until water is dissolved completely by adding water to the water soluble polymer, the hydrophilic monomer (if employed), and the adjuvant; b. The reactor temperature is kept stable at the required reaction temperature of 30 to 90 ° C., and the hydrophobic monomer is added to the reactor by one or more times or by dropping method, and the initiator is added for 4 to 35 hours, more preferably 5 to 20 hours. Preparing a polymer colloidal emulsion by performing a time polymerization reaction; c. The weight ratio of each component in a polymer colloid is 100 weight part of water-soluble polymers, 0-200 weight part of hydrophilic monomers, 30-500 weight part of hydrophobic monomers, and 1-5 weight part of initiators. The water-soluble polymer is polyvinyl alcohol, polyvinylpyrrolidone or a water-soluble copolymer thereof, polyoxyethylene, the degree of polymerization of polyvinyl alcohol is 1700-2400, the degree of hydrolysis is 50-99. The molecular weight of polyvinylpyrrolidone and its water-soluble copolymer is 500 to 100,000, preferably 1 to 30,000. The molecular weight of polyoxyethylene is 100,000-2 million.

The hydrophobic (lipophilic) monomer is represented by the following formula (1):

[Formula 1]

CH ₂ = CR ¹ R ²

In Chemical Formula 1,

R ¹ is -H or -CH ₃ ,

R ² is -C ₆ H ₅ , -OCOCH ₃ , -COOCH ₃ , -COOCH ₂ CH ₃ , -COOCH ₂ CH ₂ CH ₂ CH ₃ , -COOCH ₂ CH (CH ₂ CH ₃ ) CH ₂ CH ₂ CH ₂ CH ₃ or -CN;

The hydrophobic monomer is used by mixing any one or at least two or more of the hydrophobic monomers.

In order to improve the affinity of the separator for the electrolyte, a hydrophilic monomer may be added to the reaction process. The hydrophilic monomer is represented by the following formula (2):

[Formula 2]

CHR ³ = CR ⁴ R ⁵

In Chemical Formula 2,

R ³ is -H, -CH ₃ or -COOLi,

R ⁴ is -H, -CH ₃ or -COOLi,

R ⁵ is -COOLi, -CH ₂ COOLi, -COO (CH ₂ ) ₆ SO ₃ Li, -CONH ₂ , -CONHCH ₃ , , -CONHCH ₂ CH ₃ , -CON (CH ₃ ) ₂ or -CON (CH ₂ CH ₃ ) ₂ . The hydrophilic monomer is used by mixing any one or at least two or more of the above hydrophilic monomers.

The initiator is a water-soluble initiator such as ammonium persulfate, potassium persulfate, hydrogen peroxide, 2,2'-azobis (2-methyl propionamidine dihydrochloride) or oxidation of the compound composed of Na ₂ SO ₃ , FeSO _4, etc. Reduction initiation system.

In addition, it is possible to induce a certain stable action in the colloidal fluid by replacing the emulsifier with an adjuvant not exceeding 3 parts by weight in the reaction process, the adjuvant may be any one of dodecane sulfate, dodecylbenzene sulfate, vinyl sulfate. have.

2. Preparation of Polymer Colloidal Size Agent

To improve the heat resistance, porosity and membrane stiffness of the microporous polymer, ultrafine inorganic fillers can be added to the aqueous polymer colloidal emulsion. Ultrafine inorganic fillers have a high specific surface area and good surface adsorption, which is advantageous for adsorption of electrolytes and dissociation of electrolyte salts, thereby improving the ion conductivity of the membrane. In the preparation of the aqueous polymer colloidal emulsion, 0-100% of the inorganic filler and 20-100% of the plasticizer are added on the basis of the solids content of the synthesized aqueous polymer colloidal emulsion at 100%. After dispersing, milling is carried out for 2 to 10 hours, preferably 3 to 5 hours, using a ball crusher, a sand mill or a stirred ball crusher. After milling, the sizing agent removes large granulated sizing agents that have not been thoroughly milled by performing a filtration process using a screen of 200 necks or less.

The inorganic filler is an inorganic oxide such as any one of carbon white, aluminum oxide, titanium dioxide, germanium oxide, magnesium oxide, calcium carbonate and glass fibers by gas chromatography.

In order to improve the dispersibility of the inorganic filler in the polymer colloidal emulsion, a silane binder may be further added, and the binder may be 3-aminopropyltriethoxysilane, 2-aminoethyl-3-aminopropyltrimethoxysilane. , 3-epihydrin alcoholtrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane or vinyltri (2-methoxyethoxy) silane, and the amount of the silane binder added is 0.5 to about the weight of the inorganic filler. 5.0%.

In order to enhance the safety of the microporous reinforced nonwoven polymer membrane, a battery made of a microporous reinforced nonwoven polymer membrane by blocking the continuous flow of cations within the range of 100 to 130 ° C by adding an organic filler to enhance the ion conduction blocking characteristics of the separator. Therefore, the battery safety can be guaranteed when the battery working temperature is out of range. The micrometer-level organic filler is one of ultra fine polyethylene wax, wax oxide powder and ultra fine polyethylene wax powder. The amount of the organic filler added is 5.0 to 20% based on the solids content of the polymer colloidal emulsion at 100%.

The plasticizer may be used by mixing any one or at least two of propanediol, benzyl alcohol, normal butyl alcohol, isopropanol, triethyl phosphoric acid, diethyl phosphoric acid, trimethyl phosphoric acid, tributyl phosphoric acid and the like.

3. Preparation of Microporous Reinforced Nonwoven Polymer Membrane

Most of the polymeric materials synthesized with hydrophilic monomers have the disadvantages of being typically weak, weakly tough and sensitive to ambient humidity. In order to overcome this disadvantage, the present invention uses a flexible nonwoven fabric as a support of an aqueous polymer colloid, to prepare a microporous polymer membrane having a nonwoven fabric as a support. In the present production method, the above-mentioned aqueous polymer colloid sized agent or aqueous polymer colloidal emulsion is uniformly coated on both sides of the nonwoven fabric using a coating apparatus, and heated and dried through a drying tunnel to volatilize moisture and a plasticizer to finally be seen. The microporous reinforced nonwoven polymer membrane in the invention is produced.

The nonwoven fabric is a kind of nonwoven fabric made of polyacrylonitrile, nylon, polyvinyl foam, and polyester fibers such as polyethylene terephthalate (PET), polyolefin, and the like. The thickness of the nonwoven fabric to be used is 50 µm or less, the void is 40% or more, preferably 50 to 70%, and the void diameter is 5 to 200 µm, preferably 8 to 100 µm. The nonwoven fabric area weight is 25 g / m ² or less, preferably 10 to 20 g / m ² .

The aqueous polymer colloidal size of the present invention is coated on both sides of the nonwoven fabric through the apparatus of the coating method such as printing, pressing, pressing, roller coating, knife coating, brushing, dip coating, spray coating, casting, gradient coating, The aqueous polymer is distributed on the nonwoven surface or inside the nonwoven.

In the dry heating method of the microporous reinforced nonwoven polymer membrane of the present invention, heated air, infrared radiation or a drying method in the prior art can be utilized.

Hereinafter, the present invention will be described in more detail with reference to specific examples, but the present invention is not limited to the following examples.

Example 1 Preparation of Microporous Reinforced Nonwoven Polymer Membrane in the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

In the present embodiment, a hydrophilic polymer polyvinyl alcohol (PVA) 1750 and a lipophilic monomer vinyl acetate (VAC) / ethyl acrylate (EA) / acrylonitrile (AN) were subjected to graft hybrid polymerization in an aqueous solution to form a lithium battery separator. An aqueous polymer colloidal emulsion used for was prepared. The composition of the hybridization was PVA: VAC: EA: AN = 10: 2: 2: 5 (weight ratio, the same below), the copolymer content was 17%, and the product was a white opaque emulsion.

In the specific method for preparing the polymer colloidal emulsion, 1000 g of distilled water and 100 g of polyvinyl alcohol (PVA) 1750 were added to a four-necked reactor containing condensed water, and the reactor temperature was raised to 75 ° C., followed by a rate of 100 times / minute. After stirring for 3 hours, when the raw material formed a transparent phase, it judged that melt | dissolution was completed, and heating was stopped and it cooled naturally to 55 degreeC. 40 g of a blend having a 1: 1 ratio of lipophilic monomer vinyl acetate (VAC) and ethyl acrylate (EA) was added once, stirred and dispersed for 10 minutes, and 0.5 g of aqueous initiator ammonium persulfate (aps) ), And after about 20 minutes, the sample had a light blue color, and after 30 minutes, it turned to a white emulsion, reacting for a total of 2 hours to prepare a reaction intermediate.

The reaction solution and 50 g of lipophilic monomer acrylonitrile (AN) are mixed and dispersed, 1.5 g of initiator ammonium persulfate (aps) and 0.5 g of weakly acidic vinyl lithium sulfate (SVSLi) are polymerized in emulsion, and then subjected to a 10-hour reaction to form a polymer colloid. An emulsion was prepared.

Step 2. Prepare Sized

19 g of germanium dioxide filler and 160 g of benzyl alcohol plasticizer were added to the prepared polymer colloid emulsion, and a ball mill was carried out for 5 hours. The viscosity of the sized agent was measured under a temperature environment of T = 20.6 ° C. and RH = 64%: T _{sized agent} = 35 ° C., viscosity = 2500 mpa · s.

Step 3. Coating

The sized agent was coated on a PET nonwoven fabric having a thickness of 24 μm and a surface weight of 17 g / m ^{2 by} a double roller pressing method (belt speed 2 m / min). Volatilized. In the following examples the coating was carried out using the same method or apparatus. Finally, a microporous polymer membrane having a thickness of 25 μm and an average pore diameter of 400 to 600 nm was prepared.

The gas permeability of the prepared membrane was about 20 (S / in ² · 100 ml · 1.22 KPa), and the unit indicates the time required for the 100 ml atmosphere to pass through a 1 square inch area under 1.22 Kpa pressure conditions (the same example is also described below). do.

Example 2 Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

The reaction procedure is similar to Example 1, with the difference being that the lipophilic monomer ethylacrylate (EA) is replaced with acrylamide having good hydrophilicity, and the polymerization composition is PVA: VAC: AM: AN = 10: 2: 1: 8

In the specific method of preparing the polymer emulsion, all monomers were added by the primary injection method, the sample concentration was adjusted to about 13%, and the initiator was added directly to prepare a polymer colloidal emulsion after the reaction for 12 hours.

Step 2. Prepare Sized

The filler content was the same as in Example 1, and the materials were titanium dioxide and benzyl alcohol, and a ball mill was carried out for 5 hours.

Step 3. Coating

The gas permeation rate of the prepared membrane was about 40 (S / in ² · 100 ml · 1.22 KPa) as in Example 1.

Example 3 Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

In this embodiment, the lipophilic monomer phenylethylene (St) / butylacrylic acid (Ba) / acrylonitrile (AN) is added to an aqueous polyvinylpyrrolidone solution, and three-dimensional copolymerization is carried out on the aqueous solution. : St: Ba: AN = 10: 2: 4: 2 (weight ratio, the same also as below), and copolymer content was 15%.

In the polymer emulsion, 1000 g of distilled water and polyvinylpyrrolidone were introduced into a four-neck reaction vessel containing condensed water through a sub-step polymerization method, and the sample formed a transparent phase after raising the temperature of the reactor to 90 ° C. It dissolved until stirring. 2 g of phenylethylene (St) monomer and 2 g of ammonium persulfate initiator were added and reacted for 20 hours. When butyl acrylate (Ba) was added, the reaction was continued for 2 hours. Subsequently, 20 g of acrylonitrile monomer was added to the reaction solution, and 1.5 g of initiator was added to polymerize for 12 hours to prepare a polymer colloidal emulsion.

Step 2. Prepare Sized

15% of silicon dioxide filler and 100% of tributylphosphate plasticizer were added to the prepared polymer colloidal emulsion, followed by a ball mill for 5 hours. The viscosity of the size was adjusted to 2500 mpa * s.

Step 3. Coating

It carried out similarly to Example 1, and the gas permeability of the prepared membrane was about 15 (S / in ² · 100 ml · 1.22 KPa).

Example 4 Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

In this embodiment, polyvinyl alcohol 1799 (PVA), hydrophilic monomer vinylpyrrolidone (NVP), lipophilic monomer butylacrylic acid (Ba) and acrylonitrile (AN) are copolymerized, and the copolymerization composition is PVA: NVP. : Ba: AN = 10: 2: 4: 5 (weight ratio).

The polymer colloidal emulsion was obtained by a one-step polymerization method, and the monomer and the initiator were added at the same time, and the initiator used ammonium sulfate-potassium sulfate as an oxidation-reduction system, the reaction temperature was 50 ° C., and the reaction time was 12 hours. It was. Finally, a polymer colloidal emulsion was prepared.

Step 2. Prepare Sized

To the prepared polymer colloidal emulsion, 15% of silicon dioxide filler treated with 2% binder and 100% of triethylphosphite plasticizer were added. The viscosity of the size was adjusted to 2500 mpa · s.

Step 3. Coating

The same process as in Example 1 was carried out, and the gas permeability of the prepared membrane was about 56 (S / in ² · 100 ml · 1.22 KPa).

Example 5 Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

In this embodiment, PVA, hydrophilic monomer lithium acrylate, and lipophilic monomer acrylonitrile (AN) were polymerized in an aqueous solution to prepare an aqueous polymer colloidal emulsion used for a lithium battery separator. The composition of this polymerization was PVA: MAALi: AN = 10: 2: 5 (weight ratio).

A specific method for preparing the polymer colloidal emulsion is: completely dissolving polyvinyl alcohol 1788 at 90 ° C. and allowing the temperature to drop to 50 ° C., firstly adding acrylic acid and acrylonitrile monomer, and the polymerization method is carried out as described above. In the same manner as in the example, the polymerization was completed in 12 hours.

Step 2. Prepare Sized

30% aluminum oxide filler and 120% triethylphosphite plasticizer were added to the prepared polymer colloidal emulsion, and 35% polyethylene oxide wax powder was added to improve adhesion of the BOPP material of the separator. The ball mill was advanced for 5 hours, and the viscosity of the size was adjusted to 2500 mpa * s.

Step 3. Coating

It carried out similarly to Example 1, and the gas permeability of the prepared membrane was about 12 (S / in ² · 100ml. 1.22KPa).

Example 6 Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

In this example, an aqueous polymer emulsion was prepared by graft hybrid polymerization of polyvinyl alcohol 1799 (PVA) and hydrophobic monomer vinyl triethoxysilane binder (151) / acrylonitrile (AN) in an aqueous solution. The composition of the copolymer was PVA: 151: AN = 10: 4: 5 (weight ratio).

In the method for producing the polymer colloid emulsion, 1000 g of distilled water and 100 g of hydrophilic monomer polyvinyl alcohol (PVA) 1799 were added to a four-neck reaction vessel containing condensed water, and heated to 90 ° C. until it became a transparent phase. 40 g of vinyl triethoxysilane (151), 50 g of acrylonitrile (AN), and 1.9 g of initiator ammonium persulfate were added thereto, followed by graft polymerization for 12 hours to prepare a polymer colloidal emulsion.

Step 2. Prepare Sized

Triethyl phosphite in which the silicon oxide filler was dispersed was added to the polymer emulsion. The specific content is 20% of silicon oxide filler and 100% of triethylphosphite plasticizer. 30% of alkali-free glass fiber was added, and the glass fiber was pre-baked at a high temperature of 500 ° C. in a muffle furnace, and the inside of the electric furnace was naturally cooled to stand by. After mixing, a ball mill was carried out for 5 hours to adjust the viscosity of the sized product to 2500 mpa · s.

Step 3. Coating

It carried out similarly to Example 1, and the gas permeability of the prepared membrane was about 30 (S / in ² · 100 ml · 1.22 KPa).

Example 7 Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

In this embodiment, the hydrophilic monomer acrylamide (AM), the lipophilic monomer vinyl acetate (VAC) / ethyl acrylate (EA) and the lipophilic monomer acrylonitrile (AN) are copolymerized in an aqueous solution to obtain a polymer colloidal emulsion. Manufactured. The copolymer composition was AM: (VAC + EA): AN = 2: 3: 3 (weight ratio, the same as below), and the copolymer content was 17%.

In the method for producing a polymer emulsion, 100 parts by weight of distilled water and 5 parts by weight of hydrophilic acrylamide (AM) monomer are added to a four-neck reaction vessel containing condensed water and dissolved by stirring at a rotational speed of 100 times / minute. When the raw material in the reactor forms a transparent phase, it is judged that the dissolution is completed, and 7.5 parts by weight of a mixture of a lipophilic monomer vinyl acetate (VAC) and ethyl acrylate (EA) is added once or several times, followed by stirring for 10 minutes, and an aqueous initiator. 1 part by weight of ammonium persulfate (aps) and 0.5 part by weight of a regulator were added to form a reaction intermediate through a copolymerization reaction for 2 hours.

7.5 parts by weight of the reaction solution and the lipophilic monomer acrylonitrile (AN) were mixed, and 0.5 parts by weight of the initiator and 0.2 parts by weight of weakly acidic vinyl lithium sulfate (svsLi) were added to perform the emulsion polymerization reaction for 10 hours. Prepared.

Step 2. Prepare Sized

It carried out similarly to Example 1.

Step 3. Coating

Example 1 was set as follows, the gas permeability film produced is about ^{25 (S / in 2 · 100ml} · 1.22KPa).

Example 8. Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

The reaction procedure is similar to that of Example 1, except that the mixture of lipophilic monomer vinyl acetate (VAC) and ethyl acrylate (EA) is 2.5 parts by weight of hydrophilic methacrylic acid (MAA), lipophilic monomer acrylonitrile (AN) 5 Substituted by weight part, the weakly acidic vinyl lithium sulfate was polymerized by replacing with a strong acid lithium dodecylsulfate (DsLi) emulsion. The polymerization composition was AM: MAA: AN = 2: 1: 2, the copolymer content was 11%, and the product was a white translucent colloid.

Step 2. Prepare Sized

It carried out similarly to Example 3.

Step 3. Coating

The same process as in Example 1 was carried out, and the gas permeability of the prepared membrane was about 40 (S / in ² · 100 ml · 1.22 KPa).

Example 9 Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

100 parts by weight of distilled water, 2 parts by weight of hydrophilic monomer acrolic acid and 8 parts by weight of acrylamide were added to a four-necked reaction vessel containing condensed water, and the temperature was raised to 60 ^° C., followed by stirring and dissolving. 4 parts by weight, emulsifier lithium dodecyl sulfate (DsLi), and 0.6 parts by weight of a stabilizer polyvinyl alcohol (PVA1788) were added, and 0.1 parts by weight of the redox ammonium sulfate-sodium persulfate was used as an initiator, and the reaction time was 2 hours.

The reaction solution and 16 parts by weight of the lipophilic monomer acrylonitrile (AN) were emulsion-polymerized for 12 hours, the copolymer composition was AM: MAA: BA: AN = 2: 0.5: 1: 4, and the copolymer content was 17%.

Step 2. Prepare Sized

It carried out similarly to Example 1.

Step 3. Coating

The same process as in Example 1 was carried out, and the gas permeability of the prepared membrane was about 20 (S / in ² · 100 ml · 1.22 KPa).

Example 10 Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

100 parts by weight of distilled water and 10 parts by weight of hydrophilic monomer polyvinyl alcohol (1788) were added to a four-necked reaction vessel containing condensed water, and the melting temperature was 80 ° C. for stirring and dissolution. The concentration of the solution is 10%.

After complete dissolution (transparent phase), the reaction temperature was cooled to 50 ° C. 2 parts by weight of the lipophilic mixed monomer acrolic acid and 8 parts by weight of vinyl acetate, and protected by injecting nitrogen, 0.3 parts by weight of ammonium persulfate and 0.1 parts by weight of a regulator, and slowly dropping the third monomer A polymer colloidal emulsion was prepared by introducing 10 parts by weight of acrylonitrile (AN) and performing graft hybrid polymerization for at least 10 hours.

Step 2. Prepare Sized

It carried out similarly to Example 1.

Step 3. Coating

It carried out similarly to Example 1, and the gas permeability of the prepared membrane was about 35 (S / in ² · 100ml. 1.22KPa).

Example 11 Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

100 parts by weight of distilled water was added to a four-necked flask, the water bath was heated to 80 ° C., and 15 parts by weight of PVA granules were added to maintain the temperature until the solution became clear, and the pH value was adjusted to acid by adding glacial acetic acid. Subsequently, 1 part by weight of formaldehyde or butylaldehyde was added and the reaction was carried out for 3 to 5 hours, followed by addition of strong alkali to adjust the pH value to neutral. The temperature is maintained at 70 ° C. and 3 parts by weight of tributylphosphate are added, followed by stirring for a certain time. Then, 0.6 parts by weight of APS is added and 15 parts by weight of lipophilic monomer AN are slowly added dropwise to complete the drop within 3 to 5 hours. The reaction time was 12 hours after the solution turned ivory. A polymer emulsion having a concentration of 33% was prepared.

Step 2. Prepare Sized

It carried out similarly to Example 3.

Step 3. Coating

It carried out similarly to Example 1, and the gas permeability of the prepared membrane was about 60 (S / in ² · 100ml. 1.22KPa).

Example 12 Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

100 parts by weight of distilled water was added to a four-necked flask, 8 parts by weight of PVA granules were added, followed by heating until the solution became clear, 4 parts by weight of hydrophilic monomer acrylic acid and 8 parts by weight of lipophilic monomer acrylonitrile were added to the solution several times. Furthermore, after 0.1 weight part of peroxide initiators were added dropwise, the temperature was maintained at 55 degreeC and it was made to react for 12 hours, and the polymer colloid emulsion of 20% of concentration was produced.

Step 2. Prepare Sized

It carried out similarly to Example 1.

Step 3. Coating

Example 1 was set as follows, the gas permeability film produced is about ^{15 (S / in 2 · 100ml} · 1.22KPa).

Example 13. Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

125.0 g of acrylamide (AM) was stirred and dissolved in 1800.0 ml of water, 75.0 ml of vinyl acetate (VAC) and 15.0 ml of isopropyl alcohol (IPA) were added, and N ₂ was added at 60 ° C. to remove oxygen for 40 min. 2.0 g of an initiator ammonium sulfate (AP) was added to gradually increase the viscosity of the raw material, and after 40 minutes from the start of the reaction, when the solution turned to ivory color, 125.0 ml of AN was added dropwise to prepare a polymer colloidal emulsion through copolymerization.

Step 2. Prepare Sized

30% aluminum oxide filler and 120% triethylphosphite plasticizer were added to the prepared polymer colloid emulsion, and 35% polyethylene wax powder was added, followed by a ball mill for 5 hours to adjust the viscosity to 2500 mpa · s. .

Step 3. Coating

Example 1 was set as follows, the gas permeability film produced is about ^{38 (S / in 2 · 100ml} · 1.22KPa).

Example 14 Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

50.0 g of acrylamide (AM) was stirred and dissolved in 725.0 ml of water, 40.0 ml of vinyl acetate (VAC), 15.0 ml of isopropyl alcohol (IPA) and 127.0 ml of triethylphosphite were added thereto, and N ₂ was added at 60 ° C. After removing oxygen for 40 minutes, 0.8 g of initiator ammonium sulfate (AP) was added to gradually increase the viscosity of the raw material.If the solution turned ivory 3.0 hours after the start of the reaction, 50.0 ml of AN was added dropwise to obtain a copolymer colloid emulsion. Was prepared.

Step 2.

The polymer colloidal emulsion obtained through the copolymerization was cooled to room temperature and coated on a nonwoven fabric to prepare a microporous polymer membrane.

Step 3. Coating

Example 1 was set as follows, the gas permeability film produced is about ^{12 (S / in 2 · 100ml} · 1.22KPa).

Example 15 Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

20.0 g of AM was stirred and dissolved in 400.0 ml of water, 11.2 g of lithium methyl acrylate, 5.0 ml of IPA, 50.0 ml of TEP, and 30.0 ml of VAC were added, and oxygen was removed by passing N ₂ at 60 ° C. for 40 minutes. The solution viscosity was gradually increased by adding 0.5 g of initiator AP, and 40.0 ml of the remaining VAC was added dropwise after 1.0 hour to prepare a polymer colloidal emulsion through copolymerization.

Step 2. Prepare Sized

It carried out similarly to Example 14.

Step 3. Coating

Example 1 was set as follows, the gas permeability film produced is about ^{10 (S / in 2 · 100ml} · 1.22KPa).

Example 16 Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

25.0 g of AM was stirred and dissolved in 400.0 ml of water, and 10.0 ml of normal butyl acrylate (BA) and 1.0 ml of IPA were added thereto to remove oxygen by passing N ₂ at 60 ° C. for 30 minutes, and initiator AP 0.5 After adding g gradually increasing the viscosity of the solution and reacting for about 20 minutes to change to ivory color, 30.0 ml of AN was added dropwise to prepare a polymer colloidal emulsion through copolymerization.

Step 2. Prepare Sized

It carried out similarly to Example 3.

Step 3. Coating

It carried out similarly to Example 1, and the gas permeability of the prepared membrane was about 30 (S / in ² · 100ml. 1.22KPa).

Example 17 Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

25.0 g of AM was stirred and dissolved in 400.0 ml of water, 6.6 ml of VAC, 3.3 ml of BA, and 1.0 ml of IPA were added to remove oxygen by passing N ₂ at 60 ° C. for 50 minutes, and then the initiator AP was 0.5 g was added to gradually increase the solution viscosity and reacted for about 15 minutes to turn blue, and then 30.0 ml of AN was added dropwise to copolymerize to prepare a polymer colloidal emulsion.

Step 2. Prepare Sized

30% aluminum oxide filler and 120% propylene glycol plasticizer were added to the prepared polymer colloidal emulsion, and 20% polyethylene wax powder was added. A ball mill was carried out for 5 hours to adjust the viscosity of the sized product to 2500 mpa · s.

Step 3. Coating

Example 1 was set as follows, the gas permeability film produced is about ^{42 (S / in 2 · 100ml} · 1.22KPa).

Example 18 Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

Step 1. Synthesis of Polymer Colloidal Latex

25.0 g of AM was stirred and dissolved in 400.0 ml of water, 1.8 g of lithium methyl acrolate, 10.0 ml of BA, and 1.0 ml of IPA were added, and oxygen was removed by passing N ₂ at 60 ° C. for 50 minutes. Then, 0.5 g of the initiator AP was added to gradually increase the solution viscosity and reacted for about 15 minutes to turn blue. Then, 30.0 ml of AN was added dropwise to prepare a polymer colloidal emulsion through copolymerization.

Step 2. Prepare Sized

30% aluminum oxide filler and 120% benzyl alcohol plasticizer were added to the prepared polymer colloidal emulsion. A ball mill was carried out for 5 hours to adjust the viscosity of the sized product to 2500 mpa · s.

Step 3. Coating

It carried out similarly to Example 1, and the gas permeability of the prepared membrane was about 31 (S / in ² · 100 ml · 1.22 KPa).

Example 19 Preparation of Microporous Reinforced Nonwoven Polymer Membrane According to the Present Invention

  Step 1. Synthesis of Polymer Colloidal Latex

23.0 g of AM was stirred and dissolved in 300.0 ml of water, 15.0 ml of VAC and 4.0 ml of IPA were added to remove oxygen by passing N ₂ at 60 ° C. for 30 minutes, and then 0.3 g of initiator AP was added to add viscosity to the solution. After gradually increasing the color to white, 46.0 ml of AN and 2.0 g of aqueous solution of 2.0 g of lithium methyl acrylate were added to form a polymer colloidal emulsion through copolymerization.

Step 2. Prepare Sized

It carried out similarly to Example 1.

Step 3. Coating

It carried out similarly to Example 1, and the gas permeability of the prepared membrane was about 35 (S / in ² · 100ml. 1.22KPa).

Experimental Example 1: Heat resistance of the microporous reinforced nonwoven polymer membrane according to the present invention

  Refer to Table 1 below for shrinkage at different temperatures of various separators. Table 1 shows that the microporous reinforced nonwoven polymer membrane according to the present invention has better heat resistance than the conventional PP (polypropylene), PE (polyethylene) and microporous polymer membrane.

[Table 1] Shrinkage by Temperature of Various Membranes

Separation membrane Shrinkage Ratio by Temperature (%) 90 ℃ 100 ℃ 110 ℃ 130 ℃ 150 ℃ 170 ℃ 180 ℃ PP 3.6 11.6 14.2 － transform Fusion － PE 4 7.6 transform Fusion － － － Example 1 0 － 0.6 1.0 1.2 1.4 1.6 Example 3 0 － 0.4 0.8 1.2 1.2 1.4 Example 6 0 - 0.5 1.1 1.2 1.2 1.6 Example 9 0 - 0.3 0.8 1.0 1.1 1.4 Example 12 0 - 0.4 0.8 0.9 1.1 1.4 Example 15 0 - 0.5 0.8 1.1 1.3 1.4 Example 17 0 - 0.6 1.0 1.3 1.5 1.8 Example 19 0 - 0.3 0.7 0.8 1.0 1.2

Note: 2 hours vacuum treatment at each temperature condition, the film thickness of each example, PP and PE film thickness is about 25 μm.

Table 1 relates to shrinkage under various temperature conditions of a microporous reinforced nonwoven polymer membrane in accordance with some embodiments. Shrinkage of the microporous reinforced nonwoven polymer membrane according to the present invention under 170 ℃ condition is 1.5% or less, the commercialized PP and PE microporous polymer membrane is melted under the above temperature conditions, so the microporous reinforced nonwoven polymer membrane according to the present invention shows good heat resistance This feature is very advantageous for improving the safety of the battery. At the same time, the microporous reinforced nonwoven polymer separator according to the present invention is not sensitive to ambient humidity, so that the membrane size can be stably maintained even at high atmospheric humidity.

Experimental Example 2: Cyclic performance of the microporous reinforced nonwoven polymer membrane according to the present invention

A lithium ion battery was assembled using the microporous reinforced nonwoven polymer membrane prepared in Example 6, and the battery was composed of an anode material of LiMn ₂ O ₄ , an anode material of graphite, and an electrolyte composed of ethylene carbonate / diethyl carbonate and LiPF 6. Configured. The cell was subjected to a 100% DOD charge and discharge cycle under 1 C conditions. According to the experimental results, the solution after 1000 cycles retained 80% or more of its initial capacity and the internal resistance increase rate of the battery was 10% or less. On the other hand, after 400 cycles of the lithium ion battery assembled with the microporous polypropylene membrane under the same conditions, the capacity was about 75% of the initial capacity and the battery internal resistance increase rate was 35% or more.

Experimental Example 3: Cyclic performance of the microporous reinforced nonwoven polymer membrane according to the present invention

A lithium ion battery was assembled using the microporous reinforced nonwoven polymer membrane prepared in Example 15, which was composed of an anode material of LiCoO ₂ , an anode material of graphite, and an electrolyte composed of ethylene carbonate / diethyl carbonate and LiPF ₆ . It is composed. The battery was charged and discharged at 100% DOD under 1C conditions. According to the experimental results, the solution capacity of the battery after 1000 cycles was 85% or more of the initial capacity, and the increase in battery internal resistance was 10% or less.

Experimental Example 4: Circulation performance of the microporous reinforced nonwoven polymer membrane according to the present invention

A lithium ion battery was assembled using the microporous reinforced nonwoven polymer membrane prepared in Example 15, and the battery was composed of an anode material of LiFePO ₄ , an anode material of graphite, and an electrolyte composed of ethylene carbonate / diethyl carbonate and LiPF ₆ . do. The battery was subjected to a 100% DOD charge and discharge cycle under 1C conditions. According to the experimental results, the capacity after 2000 cycles was maintained at 80% or more of the initial capacity, and the increase in battery internal resistance was 20% or less.

The lithium ion battery assembled with the microporous reinforced nonwoven polymer membrane according to the present invention has a long cycle life and a relatively small cellification due to the microporous polymer membrane reinforced with the nonwoven fabric and has a high polarity (for example,- The main material of the polymer compound, including CN, -COO-, -NH ₂ , -O-, etc., has good solubility with a nonaqueous electrolyte and can form a polymer colloid, and is a super solvent of a polar group and a nonaqueous electrolyte. Exerts a chemical bonding action to allow the electrolyte in the cell to exhibit solid properties and to maintain the membrane in a good wet state.

Therefore, the microporous reinforced nonwoven polymer membrane according to the present invention has a good battery manufacturing potential as a nonaqueous electrolyte lithium ion battery separator, and provides good electrical performance, high safety reliability, and long cycle life for electric devices such as batteries and capacitors.

Claims (10)

100 parts by weight of water-soluble polymer, 30 to 500 parts by weight of hydrophobic monomer, 0 to 200 parts by weight of hydrophilic monomer, and 1 to 5 parts by weight of initiator are prepared to prepare a polymer colloidal emulsion, and then the content of solid content of the prepared polymer colloidal emulsion is 100%. It is prepared by coating and drying the sized agent obtained by adding 0-100% of inorganic filler and 20-100% of plasticizer on both sides of the nonwoven fabric, The nonwoven fabric is a microporous reinforced nonwoven polymer membrane, characterized in that the non-woven fabric made of polyacrylonitrile, nylon, polyvinyl foam, polyolefin or polyester fibers. The method of claim 1, The water-soluble polymer is a polyvinyl alcohol, polyoxyethylene, polyvinylpyrrolidone or polyvinylpyrrolidone water-soluble copolymer, the degree of polymerization of the polyvinyl alcohol is 1700 ~ 2400 and the degree of hydrolysis is 50 ~ 99, the polyoxy The molecular weight of ethylene is 100,000 to 2 million, and the molecular weight of the polyvinylpyrrolidone or polyvinylpyrrolidone water-soluble copolymer is 500 to 100,000; The hydrophobic monomer is at least one of the hydrophobic monomer represented by the formula (1): [Formula 1] CH ₂ = CR ¹ R ² In Chemical Formula 1, R ¹ is -H or -CH ₃ , R ² is -C ₆ H ₅ , -OCOCH ₃ , -COOCH ₃ , -COOCH ₂ CH ₃ , -COOCH ₂ CH ₂ CH ₂ CH ₃ , -COOCH ₂ CH (CH ₂ CH ₃ ) CH ₂ CH ₂ CH ₂ CH ₃ or -CN; The hydrophilic monomer is at least one of the hydrophilic monomers represented by the following formula (2): [Formula 2] CHR ³ = CR ⁴ R ⁵ In Chemical Formula 2, R ³ is -H, -CH ₃ or -COOLi, R ⁴ is -H, -CH ₃ or -COOLi, R ⁵ is -COOLi, -CH ₂ COOLi, -COO (CH ₂ ) ₆ SO ₃ Li, -CONH ₂ , -CONHCH ₃ , , -CONHCH ₂ CH ₃ , -CON (CH ₃ ) ₂ or -CON (CH ₂ CH ₃ ) ₂ ; The initiator may be ammonium persulfate, potassium persulfate, hydrogen peroxide or 2,2'-azobis (2-methyl propionamidine dihydrochloride), or redox reactions in which the compound constitutes Na ₂ SO ₃ or FeSO _4. Initiator; The inorganic filler is carbon white, aluminum oxide, titanium dioxide, germanium oxide, magnesium oxide, calcium carbonate or glass fiber; And The plasticizer is a microporous reinforced nonwoven polymer membrane, characterized in that any one or a mixture of at least two of propanediol, benzyl alcohol, normal butyl alcohol, isopropanol, triethyl phosphoric acid, diethyl phosphoric acid, trimethyl phosphoric acid, tributyl phosphoric acid. The method of claim 2, When the inorganic filler is added, a silane binder is further added, and the amount of the silane binder added is 0.5 to 5.0% of the weight of the inorganic filler, and the silane binder is 3-aminopropyltriethoxysilane, 2-aminoethyl-3-amino Microporous reinforced nonwoven polymer characterized by propyltrimethoxysilane, 3-epihydrin alcoholtrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane or vinyltri (2-methoxyethoxy) silane. Separator. The method of claim 2, An organic filler is further added, wherein the organic filler is one of polyethylene powder, polyethylene wax powder or polyethylene oxide powder. (a) 100 parts by weight of water-soluble polymer and 0 to 200 parts by weight of hydrophilic monomer are added with water until heated to dissolve, and the mixture is stirred until it is dissolved. Adding to the reactor several times or several times or in a dropwise manner and adding 1 to 5 parts by weight of an initiator to polymerize for 4 to 35 hours to prepare a polymer colloidal emulsion; (b) a size obtained by adding 0-100% of an inorganic filler and 20-100% of a plasticizer to the polymer colloidal emulsion based on 100% of the solid content of the polymer colloidal emulsion, followed by uniformly stirring and polishing for 2-10 hours. Preparing a polymeric colloidal sized agent by removing large granular material that is not polished using a screen having a pore size of 200 or less; And (c) uniformly coating and drying the water-soluble polymer colloidal sizing agent prepared on both sides of the nonwoven fabric to prepare a microporous reinforced nonwoven polymer separator; The nonwoven fabric is one of nonwoven fabrics made of polyacrylonitrile, nylon, polyvinyl foam, polyolefin or polyester fiber, the thickness of the nonwoven fabric is 50 μm or less, the voids are 40% or more, and the pore diameter is 5 to 200. The microporous reinforced nonwoven polymer membrane of claim 1, wherein the nonwoven fabric has a weight per area of 25 g / m ² or less. The method of claim 5, In step (a), an auxiliary agent not exceeding 3 parts by weight is further added, and the auxiliary agent is any one of dodecane sulfate, dodecylbenzene sulfate, and vinyl sulfate, and the initiator is added in a dropwise manner to the reaction process. Method for producing a microporous reinforced nonwoven polymer membrane, characterized in that added over a plurality of times. The method of claim 5, In the step (a), a silane binder is added during the polymerization reaction, or in the step (b), a silane binder is added simultaneously with the inorganic filler in the colloidal preparation process, and the amount of the silane binder is 0.5 to 5.0 of the weight of the inorganic filler. %, The silane binder is 3-aminopropyltriethoxysilane, 2-aminoethyl-3-aminopropyltrimethoxy silane, 3-epihydrin alcoholtrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxy A method for producing a microporous reinforced nonwoven polymer separator, characterized in that it is oxysilane or vinyltri (2-methoxyethoxy) silane. The method of claim 5, The porosity of the nonwoven fabric is 50 to 70%, the pore diameter is 8100 ㎛, the weight per nonwoven area is a method for producing a microporous reinforced nonwoven polymer membrane, characterized in that 10 to 20g / m ² . The method of claim 5, Based on the solids content in the polymer colloidal emulsion 100%, in step (b) is added 5.0 to 20% of the organic filler, the organic filler is any one of polyethylene powder, polyethylene wax powder or polyethylene oxide wax powder Method for producing a microporous reinforced nonwoven polymer membrane. A product using the microporous reinforced nonwoven polymer separator according to any one of claims 1 to 4 in the manufacture of a lithium ion battery, a super capacitor or a battery / super capacitor.