KR101887603B1 - Method of manufacturing patterned composite membrane - Google Patents

Abstract

The present invention relates to a method for manufacturing a separation film of an electrochemical element. More specifically, the present invention relates to a manufacturing method of a patterned composite separation film, which enables a continuous process by applying a polymer pattern printing technique. The manufacturing method comprises a step (a) of forming a polymer pattern layer on one surface or both surfaces of a porous substrate; a step (b) of forming an inorganic layer on the porous substrate in which the polymer pattern layer is formed; and a step (c) of removing the polymer pattern layer, and forming an inorganic pattern layer on a part in which the removed polymer pattern layer is not formed.

Description

[0001] The present invention relates to a method of manufacturing a patterned composite membrane,

The present invention relates to a process for producing a separator for an electrochemical device, and more particularly, to a process for producing a patterned composite separator capable of continuous processing by applying printing technology.

The separation membrane for electrochemical devices is an important material for stability and cell performance by blocking the contact between the anode and the cathode and acting as a path for ion movement.

Polyolefin-based separators are generally used as separators for lithium secondary batteries, and polyolefin separators are not highly thermally stable. Thus, there are limitations in application to middle-sized and large-sized secondary batteries such as electric vehicles and energy storage devices, which have recently been attracting attention.

Accordingly, a separator having improved heat resistance through a ceramic coating, a heat-resistant polymer coating, and a crosslinked polymer coating has been widely recognized.

However, when the coating is performed as described above, the pores on the surface of the separation membrane become clogged, which causes a problem that the air permeability is lowered. Accordingly, a coating method using a sputtering deposition method to coat a nanometer-scale thickness without changing the thickness of the separation membrane fabric has been proposed, but it is difficult to expect the pore structure of the separation membrane fabric itself to be maintained. As a method for solving this problem, a method of forming a mask having a pattern and depositing only a necessary coating portion to maintain the pore structure of the separator membrane (Korean Patent No. 10-1536560) has been proposed. However, It is difficult to manufacture a mask, and secondly, when a new pattern is applied, it is troublesome to replace a large-sized mask every time, so that it is difficult to apply to a continuous process.

Korean Patent No. 10-1536560 (July 15, 2015)

In order to solve the above problems, the present invention forms an elaborate pattern of various shapes up to a micrometer level by printing a solution containing a polymer on the surface of a separation membrane, depositing an inorganic material, washing and removing the polymer And to provide a method for producing a separator for an electrochemical device capable of forming a pattern easily and continuously.

Another object of the present invention is to provide a method for producing a composite membrane that can simplify the manufacturing process and improve the production yield in forming a patterned inorganic layer.

Another object of the present invention is to provide a method for producing a composite membrane capable of exhibiting maximum air permeability without modifying the pore structure of the porous substrate itself.

Another object of the present invention is to provide a method for producing a composite separator having improved adhesion between a separator and an electrode during the manufacture of a battery.

In order to accomplish the above object, the present invention provides a method of producing a patterned composite membrane,

a) forming a polymer pattern layer on one side or both sides of the porous substrate;

b) forming an inorganic layer on the porous substrate on which the polymer pattern layer is formed; And

c) removing the polymer pattern layer to form a pattern on the inorganic layer;

.

The present invention relates to a method of manufacturing a separation membrane having an inorganic coating layer on which a pattern is formed, and can provide a technique of easily forming a fine pattern on the surface of a separation membrane by applying a printing continuous process.

In the method for producing a composite membrane according to the present invention, the pore structure of the porous substrate itself is not deformed, and the ventilation characteristics can be improved.

Also, it is possible to provide a method of manufacturing a secondary battery using a high-heat-resistant ceramic coating separator and an electrode without physical deformation of the secondary battery cell during charging and discharging by improving the adhesion performance between the separator and the electrode interface.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a continuous process of the patterned composite separator of the present invention.
2 is a view showing a pattern formation process of a patterned composite separator formed by the continuous process of the present invention.
FIG. 3 shows an embodiment of a separation membrane having a dot-type polymer pattern formed thereon.
Fig. 4 shows an embodiment of a separation membrane in which a dot-shaped ceramic pattern is formed.
5 is a photograph showing a heat resistance test of a separation membrane according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described more fully hereinafter with reference to the accompanying drawings, It should be understood, however, that the invention is not limited thereto and that various changes and modifications may be made without departing from the spirit and scope of the invention.

Unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention is merely intended to effectively describe a specific embodiment and is not intended to limit the invention.

Also, the singular forms as used in the specification and the appended claims are intended to include the plural forms as well, unless the context clearly indicates otherwise.

One aspect of the present invention is

a) forming a polymer pattern layer on one side or both sides of the porous substrate;

b) forming an inorganic layer on the porous substrate on which the polymer pattern layer is formed; And

c) removing the polymer pattern layer to form a pattern on the inorganic layer;

To a process for producing a patterned composite separator.

In one embodiment of the present invention, the porous substrate may be a single layer film made of any one selected from woven fabric, nonwoven fabric, film and porous film, or a multilayer film formed by stacking two or more layers.

In one embodiment of the present invention, in the step a), the polymer pattern layer may be formed by applying and drying a binder solution or a binder emulsion.

In one embodiment of the present invention, the application of the binder solution or the binder emulsion may be selected from inkjet printing, gravure printing, gravure offset, aerosol printing, and screen printing.

In one embodiment of the present invention, the inorganic layer in step b) may be formed by one or more methods selected from dip coating, spin coating and bar coating.

In one embodiment of the present invention, the inorganic layer in step b) may be formed by one or more methods selected from electron beam deposition, sputtering, thermal deposition, laser molecular beam deposition, plasma chemical vapor deposition and pulsed laser deposition .

In one embodiment of the present invention, the inorganic layer may be formed by a sputtering method.

In one embodiment of the present invention, the sputtering method may be performed under a pressure of 10 ^-4 torr or less while maintaining the temperature at 20 to 30 ° C in an inert gas atmosphere.

In one embodiment of the present invention, the pattern formed on the inorganic layer in the step c) may be any one or a combination of two or more selected from a circle, a polygon, a donut, a strip, a lattice, and a dot.

In one embodiment of the present invention, the removal of the polymer pattern layer in the step c) may be partially or completely removed.

In one embodiment of the present invention, when the step a) is sequentially carried out in one cycle, it may be repeated two or more cycles.

In one aspect of the present invention, the manufacturing method may be a continuous manufacturing method.

Hereinafter, each configuration of the present invention will be described in more detail.

In one aspect of the present invention, the porous substrate is not limited as long as it is conventionally used as a separator in an electrochemical device. Specifically, it may be, for example, a woven fabric, a nonwoven fabric, a film, or a porous membrane formed by a dry method or a wet method. They may be multilayer films formed by laminating one layer or two or more layers.

The material of the porous substrate is not particularly limited, but specific examples thereof include polyethylene, polypropylene, polybutylene, polypentene, polymethylpentene, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyamide, polycarbonate , Polyimide, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, polyethylene naphthalene, copolymers thereof, and the like, or a mixture of two or more thereof.

In addition, the thickness is not limited and may be 10-500 [mu] m, which is usually used in the art, but is not limited thereto.

In addition, the porosity is not limited as long as it satisfies the porosity required in the field in general, and may be, for example, a porosity of 30 to 90%.

In one embodiment of the present invention, the step of forming the polymer pattern layer means that a polymer-coated portion and a non-coated portion form a pattern on one or both surfaces of the porous substrate. More specifically, for example, the binder solution or the polymer may be formed by applying and drying a binder emulsion in which water or an organic solvent is dispersed. The binder solution means that the polymer is dissolved in water, an organic solvent or a mixture thereof, and the binder emulsion means that the polymer is dispersed in water, an organic solvent, or a mixture thereof.

The polymer is not limited as long as it can be removed by using water, an organic solvent or a mixed solvent of water and an organic solvent. More specifically, examples thereof include polyvinyl alcohol, polyethylene glycol, carboxymethylcellulose, ethylene-propylene-diene terpolymer, styrene-butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, tetrafluoroethylene-hexafluoro Polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trichlorethylene, polymethyl methacrylate, polyacrylonitrile, polyvinyl pyrrolidone, polyvinyl acetate, ethylene vinyl acetate But are not limited to, copolymers such as polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinyl alcohol, cyanoethylcellulose, cyanoethyl sucrose, fluoran, acrylonitrile- Stadiene-butadiene A copolymer, a polyimide, and the like, but is not limited thereto. The content of the polymer used in the binder solution or the binder emulsion is not limited, but may be 0.01 to 10% by weight based on the total weight of the solid content, and is easily applied to the inkjet method and the like in the above range.

The organic solvent is not limited as long as it can dissolve or disperse the polymer, and may be one which has a solubility index similar to that of the polymer used to uniformly mix with the polymer. In addition, a solvent having a high boiling point may be used in order to prevent clogging of nozzles according to the coating method described later. Further, in the subsequent step, heat is applied to the polymer pattern to remove the organic solvent. In this case, it is preferable that the boiling point is not excessively high in order to easily remove the organic solvent, but the solvent having a high boiling point is not excluded. And more specifically, those having a boiling point in the range of 60 to 200 占 폚, but are not limited thereto. Nonlimiting examples of the organic solvent include organic solvents such as cyclohexane, mesitylene, dimethylacetamide, dimethylsulfone, dimethyl carbonate, acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, Methyl ethyl ketone, methyl acetate, cyclohexanone, ethanol, methanol, isopropyl alcohol, and the like.

In one embodiment of the present invention, the method of applying the binder solution or the binder emulsion to form a predetermined pattern is not limited as long as it is a coating method capable of forming a pattern on a porous substrate with a thin film. Specifically, it may be, for example, selected from inkjet printing, gravure printing, gravure offset, aerosol printing, and screen printing, but is not limited thereto. More specifically, the inkjet printing method can be used, but not limited, from the viewpoint of forming a polymer pattern layer of a thin film having a thickness and a pattern of a micrometer capable of continuous production. The inkjet method is a method in which ink is printed on a substrate as droplets from a nozzle of an inkjet print. The inkjet method includes a thermal driving method, a piezoelectric element method, and the like, but may be a piezoelectric element method in view of thermal stability of a material. When the binder solution or the binder emulsion is printed by an inkjet method, a polymer pattern layer can be formed. 3 is a photograph showing an embodiment of a polymer pattern layer in which a dot-shaped pattern having a predetermined interval and size is printed using an ink-jet printing method. When the inkjet printing method is used, it is advantageous that patterns of various patterns can be continuously formed using a printer according to set values.

When the binder solution or the binder emulsion is coated on the porous substrate, the polymer can be partially impregnated into the surface and the interior of the porous substrate and is not completely impregnated, so that it is easy to remove the polymer pattern and the original porosity of the porous substrate It is desirable from the standpoint of sustainability. It is more preferable that the polymer pattern is formed on the surface by forming a predetermined pattern without being absorbed in the inside of the porous substrate.

In addition, the polymer pattern may be removed from the porous substrate by a removing method described below, wherein the removal is partially or completely removed, and when the polymer pattern is partially removed, the polymer pattern remaining on the surface of the porous substrate may exhibit adhesiveness And can improve the binding force between the electrochemical device such as the separator and the electrode.

The shape of the pattern upon application of the binder solution or the binder emulsion may be formed in consideration of the shape of the inorganic pattern to be described later. That is, in the present invention, the polymer pattern is formed using the binder solution or the binder emulsion, and the polymer pattern is removed after depositing the inorganic material, so that the inorganic pattern is formed on the portion where the polymer pattern is not formed. It may be applied in a reverse phase considering the pattern.

In addition, the polymer pattern layer can be formed by removing water or an organic solvent through a heat treatment method such as hot air after the application. At this time, the heat treatment is not limited because it can be appropriately adjusted depending on the kind of the polymer used and the kind of the organic solvent.

The thickness of the polymer pattern layer is not limited and may be a thin film in order to facilitate pepper removal. More specifically, it may be, for example, 0.1 to 50 탆 in thickness, but is not limited thereto.

In one embodiment of the present invention, the step of forming the inorganic layer may be formed on part or all of the porous substrate on which the polymer pattern layer is formed. In view of forming the inorganic pattern layer by removing the polymer pattern layer, May be formed. The inorganic material layer can be used without limitation as long as it is an inorganic material from the viewpoint of improving the mechanical properties and heat resistance of the porous substrate. For example, it may be a metal oxide, that is, a ceramic, and more specifically, for example, TiO ₂ , SiO ₂ , SnO ₂ , CeO ₂ , ZrO ₂ , CaCO ₃ , BaCO ₃ , Al ₂ O ₃ , ) ₃ and Mg (OH) ₂ And the like, but is not limited thereto. More specifically, the two or more components may be mixed to form a single layer, or a layer composed of any one or two or more components may be formed in a multilayer of two or more layers.

The inorganic layer may be formed by one or more methods selected from electron beam deposition, sputtering, thermal deposition, laser molecular beam deposition, plasma chemical vapor deposition and pulsed laser deposition, but is not limited thereto. It is also possible to form an inorganic layer by a method such as dip coating, bar coating and spin coating using a ceramic-containing composition. More preferably, the inorganic material layer may be formed by a sputtering method from the viewpoint of forming a thin film. The thickness of the inorganic material layer is not limited, but may be, for example, 1 to 1000 nm. The thickness of the inorganic material layer is not limited so long as it does not impair the permeability of the porous material in the thickness range. In addition, the thickness of the inorganic material layer may be thinner than the thickness of the polymer pattern layer, which may cause a step between a portion where the polymer pattern layer is formed and a portion where the polymer pattern layer is not formed, Therefore, the present invention is not limited thereto.

In one embodiment of the present invention, the sputtering method may be performed at a pressure of 10 ^-4 torr or less while maintaining the temperature at 20 to 30 ° C in an inert gas atmosphere such as argon, but is not limited thereto.

Further, the inorganic layer may be formed on one side or both sides of the porous substrate, more preferably, on the polymer pattern layer, thereby forming the patterned inorganic layer by removing the polymer pattern layer described later.

In one embodiment of the present invention, the step of removing the polymer pattern layer is not limited as long as it can remove the polymer, but it is preferable to remove water, an organic solvent, and the like from the viewpoint of easily removing the polymer substrate, It may be preferable to dissolve and remove the polymer using a detergent such as a mixed solvent of water and a solvent. Also, the removal may be, but is not limited to, removal using a dipping or spray method.

In addition, when the polymer pattern layer is partially removed, the polymer pattern layer may partially or completely be removed. In the case where the polymer pattern layer is partially removed, the polymer may remain on the surface of the porous substrate to exhibit adhesive strength, have. In the case where the porous substrate is completely removed, the original porosity of the porous substrate can be maintained to the maximum.

When the polymer pattern layer is removed, a predetermined pattern is formed on the inorganic layer deposited on the portion where the polymer pattern layer is not formed. The pattern formed on the inorganic layer may be any one or a combination of two or more selected from a circle, a polygon, a donut, a band, a lattice, and a dot, but is not limited thereto.

In one embodiment of the present invention, when the step a) and the step c) are sequentially carried out, one cycle may be repeated for two or more cycles. In this case, the polymer and the inorganic material used in each cycle may be the same or different. May be different. Also, the shapes of the patterns may be the same or different from each other.

In one embodiment of the present invention, step a) to c) may be produced by a continuous process.

1, a polymer pattern layer 3 is formed continuously on a porous base material 1 by using a printer 2, and then the polymer pattern layer 3 is formed by a method such as sputtering 4 The patterned composite separator 9 of the present invention can be manufactured by forming the inorganic vapor deposition layer 5 with the cleaning agent 7 and then removing the polymer pattern layer 6 with the cleaning agent 7. 1 shows an embodiment of manufacturing by an ink jet printer and a sputtering method, but it is apparent that the invention can be modified in various ways as described above.

FIG. 2 shows an embodiment in which an inorganic pattern is formed by the continuous process. The polymer pattern layer 3 is formed on the porous substrate 1, the inorganic deposit layer 5 is formed on the polymer pattern layer 3, The separation of the polymer pattern layer and the reverse phase inorganic deposit layer can be continuously performed by removing the pattern layer by washing.

FIG. 3 is an optical microscope photograph showing a separation membrane having a polymer pattern layer according to an embodiment of the present invention, and FIG. 4 is an optical microscope photograph showing a patterned composite separation membrane having an inorganic pattern layer according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail based on examples and comparative examples. However, the following examples and comparative examples are merely examples for explaining the present invention in more detail, and the present invention is not limited by the following examples and comparative examples.

The following physical properties were measured as follows.

1) Air permeability (unit: sec / 100 ml)

Samples each having a size of 60 mm in width and length were prepared and the time required for passing 100 ml of air through 4110N of Thwing-Albert (USA) was measured.

2) Heat shrinkage (unit:%)

The membranes prepared in Examples and Comparative Examples were prepared in a size of 30 mm in width and 30 mm in length, respectively. The shrinkage was measured after standing at 140 ° C for 30 minutes.

The shrinkage ratio was calculated by the following equation (1).

[Formula 1]

Heat shrinkage ratio = [(A1-A2) / A1] x 100

A1: Membrane area before heat shrinkage evaluation

A2: Membrane area after heat shrinkage evaluation

3) Surface morphology

The pattern was observed using an optical microscope.

[Example 1]

Sodium carboxymethylcellulose was dissolved in water to prepare a binder solution having a solid content of 0.05% by weight.

The above-mentioned binder solution was applied to a polyethylene microporous membrane using an ink jet printer, and dried at 60 DEG C to form a polymer pattern layer. This is shown in FIG.

Then, it was put into a sputter chamber and argon was injected. At this time, the chamber was maintained at 25 ° C., the pressure in the chamber was maintained at a vacuum of 2 × 10 ^-5 Torr, and a plasma was generated to accelerate the ionized argon gas. Then, under a pressure of 7 × 10 ^-3 Torr, / ㎠ after the pre-sputtering to the output, the Al ₂ O ₃ was deposited on the front membrane for 10 minutes.

Water was used as a cleaning agent. The polymer membrane was removed by dipping the separator in water, followed by hot air drying in an oven at 60 ° C to prepare a separator having a pattern formed on the inorganic layer. 4 is an optical microscope photograph showing that a pattern of an inorganic layer is formed.

The physical properties of the patterned composite separator were measured and are shown in Table 1 below. Also, as shown in Fig. 5 (b), it was confirmed that no heat shrinkage occurred even after holding at 140 캜 for 30 minutes.

[Example 2]

The procedure of Example 1 was repeated except that the sputtering was repeated three times in Example 1. As a result, as shown in FIG. 5 (c), it was confirmed that no heat shrinkage occurred even after holding at 140 ° C for 30 minutes.

[Comparative Example 1]

The properties of the polyethylene microporous membrane used in Example 1 were measured and are shown in Table 1 below. Also, as shown in Fig. 5 (a), it was confirmed that heat shrinkage occurred after holding at 140 캜 for 30 minutes.

Membrane Thickness (㎛) Air permeability (sec / 100 ml) Heat shrinkage (%) Example 1 20 284.3 0 Example 2 20 295.8 0 Comparative Example 1 20 276 40

As shown in the above table, the patterned composite separator prepared by the method of the present invention has a significantly improved heat exports without significantly affecting the air permeability as compared with Comparative Example 1 in which no pattern is formed.

1: Porous substrate
2: Printer
3: Polymer pattern layer
4: Sputter
5: Inorganic deposit layer
6: Polymer pattern layer removal
7: Cleaner
8: Dryer
9: Patterned composite membrane

Claims (12)

a) forming a polymer pattern layer on one side or both sides of the porous substrate;
b) forming an inorganic layer on the porous substrate on which the polymer pattern layer is formed; And
c) removing the polymer pattern layer to form an inorganic pattern layer on a portion where the removed polymer pattern layer is not formed;
≪ / RTI > The method according to claim 1,
Wherein the porous substrate is a monolayer film of any one selected from a woven fabric, a nonwoven fabric, a film, and a porous film, or a multilayer film formed by stacking two or more layers. The method according to claim 1,
In the step a), the polymer pattern layer is formed by applying a binder solution or a binder emulsion and drying the patterned polymer composite layer. The method of claim 3,
Wherein the application is selected from inkjet printing, gravure printing, gravure offset, aerosol printing, and screen printing. The method according to claim 1,
Wherein the inorganic material layer is formed by one or more methods selected from dip coating, spin coating and bar coating in the step b). The method according to claim 1,
Wherein the inorganic layer in step b) is formed by one or more methods selected from electron beam deposition, sputtering, thermal deposition, laser molecular beam deposition, plasma chemical vapor deposition and pulsed laser deposition. . The method according to claim 6,
Wherein the inorganic material layer is formed by a sputtering method. 8. The method of claim 7,
Wherein the sputtering method is carried out in an inert gas atmosphere at a pressure ranging from 10 < ^-4 > Torr while maintaining 20 to 30 deg. The method according to claim 1,
Wherein the pattern formed on the inorganic pattern layer in step c) is one or more selected from the group consisting of a circle, a polygon, a donut, a band, a lattice, and a dot. The method according to claim 1,
And removing part or all of the polymer pattern layer when the polymer pattern layer is removed in the step c). The method of claim 1, wherein
Wherein the step of repeating the steps a) to c) is repeated one cycle at least two times. 12. A compound according to any one of claims 1 to 11,
Wherein the manufacturing method is a continuous manufacturing method.

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