KR101883512B1 - Porous laminate film, separator for electricity storage device, and electricity storage device - Google Patents

Abstract

Provided are a porous laminated film having high specularity, planarity and heat resistance, excellent processability, a combination of battery performance and safety at a high level, and a separator for a power storage device. The porous laminated film is a porous layer laminated on at least one main surface of a polyolefin porous film and the polyolefin porous film. The porous laminated film is composed of a binder and a binder having an aspect ratio of 1.5 or more and 10 or less, ) Is in the range of 1.0 or more and 1.4 or less.
Ps = Rl / Rs ... (One)
Rl: radius of the least circumscribed circle
Rs: radius of maximal inscribed circle

Description

TECHNICAL FIELD [0001] The present invention relates to a porous laminated film, a separator for a power storage device, and a power storage device. [0002] POROUS LAMINATE FILM, SEPARATOR FOR ELECTRICITY STORAGE DEVICE, AND ELECTRICITY STORAGE DEVICE [

The present invention relates to a porous laminated film based on a polyolefin porous film, a separator for a power storage device comprising the porous laminated film, and a battery device comprising the separator for the power storage device.

Conventionally, polyolefin-based porous films are widely used for separator applications, particularly in power storage devices such as lithium ion secondary batteries, because they have excellent mechanical properties in addition to electrical insulation and ion permeability. In recent years, as a battery has a high output density and a high energy density, air-curing, thinning, and high air permeability of a polyolefin-based porous film have been studied (see, for example, Patent Documents 1 and 2). Further, in order to secure the safety of a power storage device using a polyolefin-based porous film as a separator, a proposal to install a layer containing a heat-resistant resin and spherical particles or a layer containing a binder and spherical particles on the outermost layer of a polyolefin- (See, for example, Patent Documents 3 and 4). It has also been proposed to provide a layer containing a binder and a platelet-like particle on the outermost layer of the film (see, for example, Patent Document 5).

Japanese Patent Laid-Open No. 11-302434 International Publication No. 2005/61599 Japanese Patent Application Laid-Open No. 2001-319634 Japanese Patent Application Laid-Open No. 2008-266593 International Publication No. 2007/66768

However, since the distance between the particles is increased in the layer containing the spherical particles, when the layer containing the spherical particles is laminated on the polyolefin-based porous film, the problem that the laminated film is easily shrunk or curled during heating there was. Further, in the layer containing the plate-shaped particles, the airtightness is increased by overlapping of the particles. Therefore, when the layer containing the plate-shaped particles is laminated on the polyolefin-based porous film, the problem that the electric resistance increases when the laminated film is used as a separator .

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to provide a porous laminated film having high specularity, planarity, heat resistance, excellent processability and cell performance when used as a separator for a power storage device, And a power storage device comprising the separator for power storage device.

In order to solve the above problems and achieve the object, a porous laminated film according to the present invention is a porous layer laminated on at least one main surface of a polyolefin-based porous film and the polyolefin-based porous film, Or more and 10 or less, and having a deformation degree (Ps) defined by formula (1) for a cross-sectional shape perpendicular to the long diameter of 1.0 or more and 1.4 or less.

Ps = Rl / Rs ... Equation (1)

Rl: radius of the least circumscribed circle

Rs: radius of maximal inscribed circle

INDUSTRIAL APPLICABILITY According to the present invention, a porous laminated film having high specularity, planarity and heat resistance can be obtained. Therefore, by using such a porous laminated film as a separator for a power storage device, it becomes possible to realize a power storage device such as a battery exhibiting good characteristics.

1 is a sectional view showing the structure of a porous laminated film according to an embodiment of the present invention.
[Fig. 2] Fig. 2 is a schematic cross-sectional view for explaining a mold releasing degree of the heat resistant particle.
[Fig. 3] Fig. 3 is a schematic view showing an example of an ellipse.
[Fig. 4] Fig. 4 is a schematic view showing an example of a spindle type.
5 is a schematic view showing an example of a polygon.
[Fig. 6] Fig. 6 is a schematic view showing an example of a molding polygon.
[Fig. 7] Fig. 7 is a schematic view showing an apparatus for planarity measurement.

Hereinafter, embodiments of the porous laminated film according to the present invention will be described in detail with reference to the drawings. The present invention is not limited by these embodiments.

1 is a cross-sectional view showing a structure of a porous laminated film according to the present embodiment. 1, the porous laminated film 10 according to the present embodiment is laminated on the main surface of at least one of the polyolefin-based porous film 11 and the polyolefin-based porous film 11, And a porous layer 12 containing a binder 12a and a binder 12b. It is possible to realize the porous laminated film 10 having excellent thermal dimensional stability by providing the porous layer 12 in the polyolefin based porous film 11 and to provide the porous laminated film 10 as a high- It is possible to realize a power storage device having good electrical characteristics and high safety.

The polyolefin-based porous film 11 used as a base material in the present embodiment has a large number of fine through-holes that penetrate both surfaces of the film and have air permeability. As a method of forming the through hole in the polyolefin film, a wet process and a dry process are known, and any of them may be used, but a dry process is preferable from the viewpoint of simplifying the process.

As the polyolefin constituting the polyolefin-based porous film 11, a single polyolefin resin such as polyethylene or polypropylene, polybutene-1 or poly-4-methylpentene-1, a mixture of these resins, Or a block copolymerized resin can be used. Of these, polypropylene is preferable.

The polyolefin-based porous film 11 preferably has a melting point of 155 to 180 캜 from the viewpoint of heat resistance. If the melting point is less than 155 캜, the dimensions of the porous film may change when the porous layer 12 is laminated on the polyolefin-based porous film 11. On the other hand, in order to make the melting point of the polyolefin-based porous film 11 exceed 180 DEG C, it is necessary to add a large amount of heat-resistant resin other than the polyolefin resin, thereby remarkably lowering the ionic conductivity as a basic property as a separator There is a case to discard. The melting point of the polyolefin-based porous film 11 refers not only to a single melting point but also to its melting point, but for example, when the polyolefin-based porous film 11 is composed of a mixture of polyolefins, , The melting point of the polyolefin-based porous film 11, which is the highest on the high-temperature side, is defined as the melting point. The melting point of the polyolefin-based porous film 11 is more preferably 160 to 180 占 폚, and more preferably 165 to 180 占 폚 in terms of heat resistance. In addition, as described above, when the polyolefin-based porous film 11 exhibits a plurality of melting points, it is preferable that all of them are within the above range.

The polyolefin-based porous film 11 is preferably composed of polypropylene in order to realize excellent cell characteristics, and is preferably a porous film produced by using a porous method called a? -Retaining method. When the polyolefin-based porous film 11 has a [beta] -cell forming ability, a porous film can be produced by densifying the film by a beta -formation method described below. The polyolefin-based porous film 11 obtained by the? -molding method is preferably used as a base material of the porous laminated film 10 because of its excellent productivity and having a pore diameter (surface pore diameter) of the surface suitable for exhibiting high pilling property .

In the present specification, the? Correction method refers to a method of forming a through-hole in a film by stretching a resin having a? Fixing ability, which will be described later, into a sheet. In order to form through holes in the film by using the? preparation method, it becomes important to produce a large amount of? -cells in a resin composition containing polypropylene (hereinafter simply referred to as polypropylene resin). For this purpose, it is preferable to use a crystallization nucleating agent, which is called a β-nucleating agent, for selectively producing β-form by adding it to a polypropylene resin as an additive. Examples of the β-nucleating agent include various pigment-based compounds and amide-based compounds, and in particular, amide-based compounds disclosed in JP-A-5-310665 can be preferably used. The content of the β-nucleating agent is preferably 0.05 to 0.5 parts by mass, and more preferably 0.1 to 0.3 parts by mass when the total amount of the polypropylene resin is 100 parts by mass.

The polypropylene resin constituting the polyolefin-based porous film 11 is an isotactic polypropylene resin having a melt flow rate (hereinafter referred to as MFR, measured at 230 캜, 2.16 kg) in the range of 2 g to 30 g / 10 min . If the MFR is out of the preferable range described above, it may be difficult to obtain a stretched film. More preferably, the MFR is 3 g to 20 g / 10 min. The isotactic index of the isotactic polypropylene resin is preferably 90 to 99.9%. If the isotactic index is less than 90%, the crystallinity of the resin is low, and it may be difficult to achieve high specularity. Commercially available resins may be used for the isotactic polypropylene resin.

From the viewpoints of stability in film forming process, uniformity of film formation property and physical properties as well as homopolypropylene resin can be used for the polyolefin-based porous film 11, it is possible to use an ethylene component such as ethylene, butene, hexene, -Olefin component in a range of 5 mass% or less may be used. The introduction of the comonomer to the polypropylene may be either random copolymerization or block copolymerization. The above-mentioned polypropylene resin preferably contains a high melt tension polypropylene in a range of 0.5 to 5 mass% from the viewpoint of film formability improvement. The high melt strength polypropylene is a polypropylene resin which is obtained by mixing a component having a high molecular weight component or a branch structure in a polypropylene resin or copolymerizing a long chain branch component with polypropylene to increase the tensile strength in a molten state, A polypropylene resin obtained by copolymerizing a polypropylene resin. For example, polypropylene resins PF814, PF633 and PF611 manufactured by Basell, WB130HMS, a polypropylene resin manufactured by Borealis, and polypropylene resins D114 and D206 manufactured by Dow are used. .

The polypropylene resin constituting the polyolefin-based porous film (11) is improved in air permeability by increasing pore forming efficiency at the time of stretching, so that the ethylene /? - olefin copolymer is added to the polypropylene resin in an amount of 1 to 10 mass% . As the ethylene /? - olefin copolymer, there can be used linear low density polyethylene or ultra low density polyethylene. Of these, an ethylene · octene-1 copolymer obtained by copolymerizing octene-1 can be preferably used. As the ethylene / octene-1 copolymer, a commercially available resin can be used.

The air permeation resistance of the polyolefin-based porous film 11 is preferably 50 to 500 sec / 100 ml. When the air permeation resistance is less than 50 sec / 100 ml, it may be difficult to maintain insulation when the porous laminated film 10 is used as a separator. If it exceeds 500 sec / 100 ml, the battery characteristics when the porous laminated film 10 is used as a separator tend to be lowered. The air permeation resistance of the polyolefin-based porous film 11 is more preferably 80 to 400 sec / 100 ml, and further preferably 100 to 300 sec / 100 ml.

The porosity of the polyolefin-based porous film 11 is preferably 60 to 90%. If the porosity is less than 60%, the characteristics when the porous laminated film 10 is used as a separator may be insufficient. If the porosity exceeds 90%, characteristics in terms of the characteristics and strength of the separator may be insufficient. The porosity of the polyolefin-based porous film 11 can be obtained from the formula (2) from the specific gravity? Of the polyolefin-based porous film 11 and the specific gravity d of the polyolefin-based resin.

The porosity (%) = [(d-rho) / d] x 100 ... (2)

The method of controlling the air permeation resistance and the porosity in such a preferable range can be achieved by using a resin obtained by mixing the polypropylene resin with the ethylene /? - olefin copolymer in the specific ratio described above. Further, it can be effectively achieved by adopting the specific biaxial stretching condition described later.

It is preferable that the polyolefin-based porous film 11 is subjected to polycondensation by the? -Molding method, so that the polypropylene resin constituting (comprising) the film preferably has a? -Cell forming ability of 40 to 90%.

Here, the term " positive definite ability " refers to a ratio of the presence of? Definition in the polypropylene resin under a certain condition, which is measured under the following conditions, and is a value indicating how much? The measurement of the β-fixability is carried out as follows. That is, 5 mg of a polypropylene resin or a polypropylene film was heated (first run) from room temperature to 240 캜 at 10 캜 / min under a nitrogen atmosphere using a differential scanning calorimeter, held for 10 minutes, Min and held for 5 minutes. Thereafter, with respect to the melting peak observed when the temperature is raised again (second run) at 10 ° C / min, the melt having the peak in the temperature range of 145 to 157 ° C is defined as the? -Defined melting peak and the peak observed at 158 ° C or more The melting is defined as? -Definition melting peak, and the heat of fusion is obtained. When the? -Defined heat of fusion is denoted by? H ?, and the defined heat of fusion is denoted by? H ?, the value calculated by the following formula (3) is referred to as?

? correction ability (%) = [? H? / (? H? +? H?)] 100 ... (3)

When the? -fixability is less than 40%, the amount of? -impurities at the time of film production is small, so that the number of voids formed in the film by using the transition to? -cell is small and as a result, only a film with low permeability can be obtained . In addition, when the positive definite forming ability exceeds 90%, coarse holes are formed, which may make it impossible to have a function as a separator for power storage devices. It is preferable to use a polypropylene resin having a high isotactic index and to add the above-mentioned β-nucleating agent in order to make the β-fixability within the range of 40 to 90%. It is more preferable that the positive definite ability is 45 to 80%.

As a method for producing the polyolefin-based porous film 11 other than the above-described? -Method method, a method called an extraction method, a method called a lamellar stretching method, or the like may be used. Here, the extraction method is a method in which, when a polypropylene is formed into a matrix resin, an extractable material is mixed as an additive and only the additive is extracted by using a good solvent of the material to form voids in the matrix resin. The lamellar stretching method is a method in which a lamellar structure in a sheet-formed stretched film is controlled by employing a low temperature extrusion and a high draft ratio at the time of melt extrusion of the film, and uniaxial stretching is performed to cause cleavage at the lamellar interface , Thereby forming voids.

The polyolefin-based porous film 11 has a ratio of the number (A) of pores having a pore diameter of 0.01 μm or more and less than 0.5 μm to the number (B) of pores having a diameter of 0.5 μm or more and less than 10 μm, ) / (B) is preferably in the range of 0.1 to 4, more preferably in the range of 0.4 to 3. When the value of (A) / (B) is less than 0.1, the large-diameter pore portion is increased on the surface of the porous film 11, so that the coating agent 11 coated on the porous film 11 at the time of forming the porous layer 12 The penetration into the openings is too much and the durability is deteriorated, which may affect the performance of the battery when used as a separator. On the other hand, when the value of (A) / (B) is more than 4, the ratio of opening of the small diameter is increased on the surface of the porous film 11, It is difficult to enter the opening portion, so that sufficient adhesiveness can not be exhibited or the sealing property may be lowered due to clogging of the hole.

The method of controlling the surface pore size in such a preferable range can be achieved by stretching the polypropylene resin to which the above-mentioned " The surface pore diameter of the polyolefin-based porous film 11 can be confirmed by photographing a surface image using a scanning electron microscope and performing image analysis.

The polyolefin-based porous film (11) is preferably stretched in at least one axial direction. When an unstretched film is used, the porosity and the mechanical strength of the film sometimes become insufficient. As a method of stretching the polyolefin-based porous film 11 in at least one axial direction, a method of stretching at a predetermined magnification by heating the unstretched film by a tenter method, a roll method, an inflation method, or a combination thereof is preferable Is used. The stretching may be uniaxial stretching or biaxial stretching. In the case of biaxial stretching, either biaxial stretching, sequential stretching, or multistage stretching (for example, simultaneous biaxial stretching and sequential stretching) may be used, but biaxial stretching is preferred.

The polyolefin-based porous film 11 may be a laminated film formed by laminating a plurality of layers having different compositions or the same composition. When a laminated film is used, the film surface properties and the characteristics of the film as a whole may be individually controlled within a preferable range. In this case, it is preferable to form a three-layer laminate of A | B | A type, but it may be a two-layer laminate of A | B type and may be a multilayer laminate of four or more layers. The lamination thickness ratio is not particularly limited as long as the effect of the present invention is not impaired.

The polyolefin-based porous film 11 may contain various additives such as an antioxidant, a heat stabilizer, an antistatic agent, a lubricant containing inorganic or organic particles, an antiblocking agent, a filler, and an incompatible polymer. In particular, for the purpose of suppressing oxidation deterioration due to thermal history of the polyolefin resin, it is preferable that the antioxidant is contained in an amount of 0.01 to 0.5 parts by mass based on 100 parts by mass of the polyolefin resin.

In the polyolefin-based porous film 11, it is preferable that the average pore diameter of the through hole is 40 nm to 400 nm. When the average pore size is less than 40 nm, the characteristics when the porous laminated film 10 is used as a separator may become insufficient. On the other hand, when the average pore size exceeds 400 nm, the heat resistant particles 12a from the porous layer 12 easily fall off or are short-circuited easily, which may affect the lifetime of the battery.

The method of controlling the average pore diameter of the through holes to such a preferable range can be achieved by using a resin in which the ethylene /? - olefin copolymer is mixed with the polypropylene resin at the above-mentioned specific ratio.

The porous laminated film 10 according to the present embodiment means a film in which the porous layer 12 is provided on at least one side of the polyolefin-based porous film 11 described above.

In the present embodiment, the porous layer 12 is composed of the heat-resistant particles 12a and the binder 12b, and indicates a layer having air permeability. The presence or absence of the air permeability of the porous layer 12 can be confirmed by evaluating the air permeability of the porous laminate film 10. [

By providing the porous layer 12, the porous laminated film 10 can impart excellent planarity and heat resistance to the polyolefin-based porous film 11. Hereinafter, the porous layer 12 will be described in detail.

The heat-resistant particles 12a used in the porous layer 12 are characterized by a shape in which the aspect ratio (long diameter of particles / short diameter of particles) is not less than 1.5 and not more than 10.

Since the particles are arranged in various directions when the particles are dispersed in the porous layer 12 by using particles having the aspect ratio within the above range, the planarity and heat resistance of the porous laminated film 10 balanced in the longitudinal direction and the width direction of the film Can be given.

When the aspect ratio is larger than 10, when the heat-resistant particles 12a are added to the polyolefin-based porous film 11 by adding to the coating liquid, the orientation becomes large and the heat resistance and planarity may be lowered. When the aspect ratio is less than 1.5, the porous laminated film 10 is easily flowed in the drying step after the coating of the coating liquid, and curling tends to occur. In addition, since the filling rate of the particles is increased, May be increased. The aspect ratio is more preferably 2 or more and 8 or less, and still more preferably 2 or more and 5 or less. It is more preferable that the heat-resistant particles 12a have a shape in which both ends of the columnar shape are closed as a whole, for example, a spiral shape in which both ends of a column are closed.

An example of the sectional shape of the heat-resistant particles 12a is shown in Fig.

The cross section 1 perpendicular to the long diameter of the heat resistant particles 12a used in the porous layer 12 has a feature that the degree of variance Ps defined by the equation (1) is 1.0 or more and 1.4 or less.

Ps = Rl / Rs ... (One)

Rl: radius of the least circumscribed circle (3)

Rs: radius of maximum inscribed circle (2)

The region of the heat-resistant particles 12a in the planar shape is reduced by the degree of deformation Ps of not less than 1.0 and not more than 1.4 and the aspect ratio of not less than 1.5 and not more than 10, ), And they exhibit excellent properties such as durability, heat resistance and planarity by forming a net-like structure.

The mold releasing degree Ps is closer to 1.0, and the shape is closer to a circle. The larger the value 1.0, the more irregular the shape becomes. If the ratio Ps is larger than 1.4, a smooth portion or irregularity is increased in the cross-sectional shape perpendicular to the long diameter of the particles, and the particles come into contact with each other at their surfaces. In this case, since the air permeation resistance is increased, there is a fear that the performance of the battery is affected when used as a separator. In addition, the filling rate of the particles per unit volume increases, so that the airtightness of the porous layer 12 increases, and the air permeation resistance of the porous layer 12 may increase. The mold releasing degree Ps is more preferably 1.0 or more and 1.3 or less, and still more preferably 1.0 or more and 1.2 or less.

The cross-sectional shape perpendicular to the long diameter of the heat-resistant particle 12a may be a circle, an ellipse, a projecting shape of a spindle, a shape formed by combining a rectangle and an arc of an arc or an ellipse, a polygon or a star polygon having five or more vertices, And a shape in which at least one of the formed shapes is selected.

In the above, the ellipse refers to a shape made up of a set of points where the sum of the distances from arbitrary two vertexes on the plane becomes constant, for example, as shown in Fig. As shown in Fig. 4, the projected shape of the spindle shape refers to a shape in which both ends of a cylindrical shape are closed (fusiform shape) on a plane parallel to the long axis. The polygon refers to, for example, a shape surrounded by a closed simple bent line in a plane as shown in Fig. As shown in Fig. 6, the star-shaped polygon refers to a shape obtained by connecting intersections obtained by extending each side of a polygon. In addition, in the case of the shape other than the above, smooth portions and unevenness in the outline of the cross-sectional shape perpendicular to the long diameter of the heat-resistant particles 12a increase and the filling ratio of the heat-resistant particles 12a per unit volume increases, 12 may increase in air permeation resistance.

In the present embodiment, the cross-sectional shape of the heat-resistant particles 12a can be confirmed by image analysis of an electron microscope photograph, that is, by finding a projected image for each individual particle taken on an electron microscope photograph.

In the present embodiment, the heat resistant particles 12a mean particles whose shape is maintained at at least 200 占 폚. More preferably, the shape is maintained up to 300 캜, and more preferably, the shape is maintained until 330 캜. That is, the phase transition accompanied by the melting point, softening point, pyrolysis temperature or volume change of the particles does not occur up to the above temperature. Concretely, particles which do not exhibit a melting point (or a softening point) up to at least 330 캜 and which retain their shape up to at least 330 캜, and as the inorganic compound, potassium titanium oxide, wollastonite, glass fiber, titanium oxide (rutile type) (Calcite, aragonite), and the like. Examples of thermoplastic resins having a melting point of 330 ° C or higher or resins having substantially no melting point include fibrous forms of nitrile aromatic compounds such as polyimide, polyamideimide and polyetherimide. Of these, calcium carbonate is preferable from the viewpoint of electrochemical stability and particle shape. When the porous laminated film 10 using calcium carbonate as the heat resistant particle 12a is used as a separator, the chemical change in the electric field is small, and the substance that inhibits the cell reaction due to decomposition is not released, It is because. The electrochemical stability of the heat-resistant particles 12a can be evaluated by measuring the cycle characteristics of the battery evaluation described later.

The average particle diameter of the heat-resistant particles 12a is preferably from 0.1 to 10 占 퐉, more preferably from 0.5 to 10 占 퐉, and still more preferably from 0.5 to 10 占 퐉, from the viewpoints of both the air permeability and mechanical properties of the porous layer 12 May be 0.8 占 퐉 to 8 占 퐉. When the average particle diameter is less than 0.1 占 퐉, the heat-resistant particles 12a penetrate the inside of the polyolefin-based porous film 11 from the porous surface of the polyolefin-based porous film 11, May be increased. On the other hand, when the average particle diameter exceeds 10 mu m, the thickness of the porous layer 12 may not be controlled. Here, the average particle diameter of the heat-resistant particles 12a refers to the particle diameter corresponding to the 50% number-based integrated value in the number-based integral curve with respect to the particle diameter measured by the laser diffraction / scattering method.

In the present embodiment, the porous layer 12 can contain fine particles (fine particles) as heat-resistant particles 12a by physically grinding primary particles of the heat-resistant particles 12a. Here, the primary particles of the heat-resistant particles 12a refer to particles obtained by mixing the heat-resistant particles 12a with water and dispersing them by ultrasonic vibration, by the above-mentioned method of measuring the average particle diameter. The particle diameter in this case is also referred to as primary particle diameter. By using the finely divided particles, voids formed by the heat-resistant particles 12a and the binder 12b in the porous layer 12 can be efficiently filled, and the surface smoothness and heat resistance of the porous layer 12 can be improved.

When the micronized particles are used in the porous layer 12, micronized particles may be used for all particles used, or primary particles not micronized may be mixed.

When the porous layer 12 contains fine particles as the heat resistant porous layer, the diameter of the particles is preferably from 0.1 to 1 mu m, more preferably from 0.2 to 0.8 mu m.

In the present embodiment, a method of physically pulverizing primary particles of the heat-resistant particles 12a to obtain finely divided particles includes a method of performing dispersion treatment with a dispersing device. Specific examples of the dispersing apparatus include a ball mill, a bead mill, a jet mill, a homogenizer, and an ultrasonic dispersing apparatus. Any method may be used.

The concentration of the heat resistant particles 12a contained in the porous layer 12 (that is, the mass ratio of the heat resistant particles 12a in the porous layer 12) is preferably 40 mass% or more and less than 90 mass%, more preferably 40 mass% , More preferably less than 80 mass%, and more preferably less than 55 mass% and less than 80 mass%. If the mass ratio of the heat-resistant particles 12a is less than 40 mass%, the heat resistance of the porous layer 12 is not sufficiently manifested and the shrinkage may become remarkable when the porous laminated film is used. On the other hand, if the mass ratio of the heat-resistant particles 12a is 90 mass% or more, the amount of the binder 12b to be described later becomes small with respect to the heat-resistant particles 12a, The planarity and heat resistance of the laminated film may be lowered. The concentration (mass ratio) of the heat-resistant particles 12a contained in the porous layer 12 can be measured by peeling the porous layer 12 from the porous laminated film 10 and recovering the sample as a sample and analyzing the recovered powder X- By identifying the type of the heat-resistant particles 12a, and then calculating the content of the inorganic element from the mass after removing the organic component by the combustion analysis.

In the present embodiment, the porous layer 12 exhibits excellent properties by fixing the structure in which the heat resistant particles 12a come into contact with each other at a point by the binder 12b.

Here, in the present specification, the binder 12b refers to a material capable of binding between different materials (intergranular particles, particle-base materials, etc.).

Examples of the binder 12b used for the porous layer 12 include polyvinylidene fluoride (PVDF), acryl, ethylene vinyl alcohol (EVA: a structural unit derived from vinyl acetate having a structural unit of 20 to 35 mol%), ethylene-ethyl acrylate (PVA), polyvinylpyrrolidone (PVP), crosslinked acrylic resin (EBR), and the like, such as ethylene-acrylic acid copolymers A water-soluble resin such as a resin, a polyurethane, an epoxy resin, a modified polyolefin, a silicon alkoxide, a zirconium compound, a colloidal silica, a compound containing an oxirane ring, and a cellulose and / or a cellulose salt. Particularly, a compound dispersible or meltable in water is preferably used as the binder 12b. As the binder 12b, the above-mentioned examples may be used singly or in combination of two or more.

In order to improve the adhesion between the binder 12b and the heat resistant particles 12a and between the porous polyolefin porous film 11 and the porous layer 12 in the porous layer 12, the binder 12b is preferably a polyolefin Is preferably a material having a lower melting point or softening point than the system porous film (11). By using such a binder 12b, it is possible to prevent the binder 12b in a molten state from being mixed with other materials (the heat-resistant particles 12a ) And / or the substrate). As a result, it is possible to suppress detachment of the heat resistant particles 12a from the porous layer 12 and peeling of the porous layer 12 from the substrate.

The melting point of the binder 12b is preferably 70 to 120 占 폚, and more preferably 80 to 110 占 폚, from the viewpoint of adhesion due to melting and binding.

When the melting point is lower than 70 占 폚, when the binder 12b is used for the porous layer 12, the heat resistance of the porous laminated film 10 may be lowered. When the melting point is higher than 120 ° C, processing at a high temperature is required when the heat-resistant particles 12a are bonded together by the binder 12b and between the heat-resistant particles 12a and the substrate by fusion, Shrinkage of the polyolefin-based porous film 11, which may result in deterioration of properties such as air permeation resistance and planarity. When processing is performed below the melting point of the binder 12b in order to suppress the deterioration of the physical properties of the polyolefin-based porous film 11 as the base material, the heat-resistant particles 12a and the heat- May be deteriorated in some cases.

The melting point of the binder 12b can be confirmed by a method to be described later. The presence or absence of melting of the binder 12b at the time of forming the porous layer 12 can be confirmed by a method to be described later.

It is preferable that the binder 12b includes a modified polyolefin in view of improving the adhesion between the binder 12b and the heat resistant particles 12a in the porous layer 12. [ When the binder 12b contains a modified polyolefin, the modified polyolefin has good affinity with both the heat-resistant particle 12a and the polyolefin-based porous film 11 to be the base material. Therefore, when the porous layer 12 is formed , The heat resistant particles 12a can be prevented from dropping off, and the porous layer 12 and the polyolefin porous film 11, which is the base material, can be favorably adhered to each other. When the adhesion between the heat-resistant particles 12a and the binder 12b is high, the heat-resistant particles 12a can be prevented from dropping off and the heat resistance that can be imparted by laminating the porous layer 12 can be effectively exhibited. If the adhesiveness of the heat resistant particle 12a and the polyolefin porous film 11 to be the base material is high, the excellent planarity of the porous laminated film 10 and the heat resistance that can be imparted by laminating the porous layer 12 can be effectively Lt; / RTI >

In the porous laminated film 10, the concentration ratio (based on mass) of the concentration of the heat resistant particles 12a and the concentration of the binder 12b in the porous layer 12 calculated by the formula (4) is preferably 0.1 or more and 1 or less , More preferably 0.2 or more and 0.7 or less.

Concentration ratio = binder concentration / heat-resistant particle concentration ... (4)

The concentration of the heat-resistant particles 12a refers to the mass ratio of the heat-resistant particles 12a in the porous layer 12 and refers to the concentration of the binder 12b, that is, the concentration of the binder 12b in the porous layer 12 ). The concentration ratio represents the ratio of these mass ratios (the ratio of the mass ratio of the binder 12b to the mass ratio of the heat resistant particles 12a).

If the concentration ratio is less than 0.1, the adhesion between the porous layer 12 and the polyolefin-based porous film 11 as a base material may deteriorate or the heat-resistant particles 12a may fall off from the porous layer 12 . When the concentration ratio is more than 1, the pores on the surface of the polyolefin-based porous film 11 are occluded and the air permeation resistance is sometimes increased. The concentration of the binder 12b contained in the porous layer 12 can be measured by peeling the porous layer 12 from the porous laminated film 10 and recovering the sample as a sample and analyzing the recovered sample by NMR or GC- . In addition, the concentration obtained from the component analysis and the concentration calculated from the amount of the coating agent are almost the same.

In the porous layer 12, when the binder 12b contains a modified polyolefin, the modified polyolefin preferably includes an olefin skeleton and an unsaturated carboxylic acid skeleton. Examples of the olefin skeleton include olefins having 2 to 6 carbon atoms such as propylene, ethylene, isobutylene, 1-butene, 1-pentene and 1-hexene. The unsaturated carboxylic acid skeleton is a compound having at least one carboxyl group or acid anhydride group in the molecule and having an unsaturated bond and specifically includes acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, Itaconic acid, fumaric acid, crotonic acid and the like, as well as half esters and half amides of unsaturated dicarboxylic acids.

The adhesion between the heat resistant particles 12a in the porous layer 12 can be evaluated by the rate of change (占 k) of the coefficient of friction? K when the film running test is conducted so that the surface of the porous layer 12 is in contact with the roll .

In the present embodiment, the rate of change (占 의) of the coefficient of friction (占)) when the film running test is conducted with the surface of the porous layer 12 in contact with the roll is preferably less than 500%, more preferably less than 300% Do. The coefficient of friction (占)) is calculated from the following equation (5) by running the film with a tape running property tester.

μk = 2 /? ln (T2 / T1) ... (5)

In the equation (5), T1 is the input tension, T2 is the output tension, and ln represents the natural logarithm.

The coefficient of friction (k) (%) of the coefficient of friction (μ) is expressed by the following equation (6): coefficient of friction (k) Quot;

K (%) = (K50) / (K1) x100 (6)

When the rate of change K is 500% or more, the heat resistant particles 12a may fall off at the time of film running, and white powder may be generated. When the porous laminate film 10 is used as a separator, the drop of the heat resistant particles 12a may cause a yield reduction of a battery assembling process or a foreign matter inclusion.

In order to set the rate of change K to a desirable range, this can be achieved by using the binder 12b described above.

Thermoplastic resin particles having a melting point of 110 to 140 占 폚 can be added to the porous layer 12 from the viewpoint of imparting shut shuttability to the film. Shutdown property refers to a property of blocking the flow of ions by blocking the through holes of the porous film by the components contained in the film when the porous film is used as a separator and abnormal heat generation of the battery occurs. If the melting point of the thermoplastic resin particles is less than 110 占 폚, there is a fear that malfunctions may occur that the through holes of the film are shielded and shut down even at a low temperature of about 110 占 폚, which has no problem with other materials of the power storage device. On the other hand, when the melting point exceeds 140 캜, the self exothermic reaction may be initiated in the electrical storage device before the shutdown. It is preferable that the shutdown property is in the range of 125 to 140 占 폚 in view of the thermal stability of the positive electrode in the case of a cobalt-based positive electrode widely used in a lithium ion battery. Therefore, the melting point of the thermoplastic resin particles is more preferably 120 to 140 占 폚, and the melting point may be changed in consideration of thermal stability of the positive electrode. When the thermoplastic resin particles have a plurality of melting points, the melting point of the highest temperature may be within the above range.

When thermoplastic resin particles are added to the porous layer 12, the thermoplastic resin particles are not particularly limited as long as they are composed of a thermoplastic resin having a melting point falling within the above range, but thermoplastic resin particles containing a polyolefin resin are preferable. Particularly preferred are polyethylene, A thermoplastic resin particle containing a polyolefin resin such as a copolymer, a polypropylene, and a polypropylene copolymer is preferable. The average particle diameter of the thermoplastic resin particles is preferably 0.5 탆 to 5 탆, more preferably 0.8 탆 to 3 탆.

When the thermoplastic resin particles are added to the porous layer 12, the concentration of the thermoplastic resin particles in the porous layer 12 (i.e., the mass ratio of the thermoplastic resin particles in the porous layer 12) is preferably 10 to 40 mass% By mass to 35% by mass. If the content is less than 10% by mass, the pores in the porous layer 12 can not be sufficiently closed at the time of heat generation when the porous laminated film 10 is used as a separator, so that shut shuttability may not be exhibited. If it exceeds 40 mass%, the heat resistance when the porous laminated film 10 is used as a separator may be lowered.

In order to improve the adhesion between the polyolefin porous film 11 and the porous layer 12 in the porous laminated film 10, the binder 12b preferably contains an oxylane ring-containing compound. Examples of the oxirane ring-containing compound include epoxy group-containing organosilicon compounds such as epoxy resin, (meth) acrylate containing an epoxy group such as glycidyl (meth) acrylate, and Y-glycidoxypropylmethyldiethoxysilane , An epoxy resin is preferably used from the viewpoint of electrolyte resistance. Specific examples of the epoxy resin include epoxy resins such as bisphenol A type epoxy resin, tetramethyl bisphenol A type epoxy resin, bisphenol F type epoxy resin, tetramethyl bisphenol F type epoxy resin, bisphenol S type epoxy resin, fluorene type epoxy resin, Type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, polyethylene oxide type epoxy resin, and polypropylene oxide type epoxy resin. These may be used alone or as a mixture of two or more. From the viewpoint of electrolyte resistance, it is preferable to use an epoxy resin having two or more functionalities. From the viewpoint of flexibility, an epoxy equivalent of 100 or more is preferable, and 300 or more is more preferable. Specific examples of the bifunctional or higher functional epoxy resin include sorbitol polyglycidoxy ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, polypropylene glycol diglycidyl ether, And polyethylene glycol diglycidyl ether. These may be used alone or as a mixture of two or more thereof. Specifically, epoxy resins such as polypropylene glycol diglycidyl ether and polyethylene glycol diglycidyl ether are particularly preferable. For the purpose of imparting flexibility, phenol ethylene oxide glycidyl ether (particularly preferably the repeating unit of the ethylene oxide chain is about 5 to 10), lauryl alcohol ethylene oxide glycidyl ether An epoxidized vegetable oil or the like may be used, and an epoxy emulsion such as a cresol novolak-type epoxy may also be used.

In addition, various curing catalysts may be used in combination for the purpose of promoting curing and low-temperature curing of these oxylane ring-containing compounds. Examples of the curing catalyst (curing agent) include acid anhydrides such as an acid such as Lewis acid, phthalic anhydride, hexahydrophthalic anhydride, anhydrous nadic acid and methylnadic anhydride, various metal complex compounds such as aluminum acetylacetonate, metal alkoxides, Organic carboxylic acid salts and carbonates of metals, aliphatic amines such as diethylenetriamine, triethylenetetraamine, tetraethylenepentamine and diethylaminopropylamine, modified aliphatic polyamines, modified aromatic polyamines, triethylamine, benzyldimethylamine, Aromatic amines such as m-phenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone; cyclic amines such as aminoethylpiperazine; and tertiary amines such as 2- (2-hydroxyphenyl) Imidazole compounds such as methyl-4-ethylimidazole and 2-methylimidazole, imidazole compounds such as triethylbenzylammonium chloride and tetramethylammonium chloride Quaternary ammonium salt, boron trifluoride, boron trifluoride-monoethylamine complex, and the like, and they may be used alone or as a mixture of two or more.

From the viewpoint that the porous laminate film 10 can adsorb to the particle surface with respect to the coating liquid forming the porous layer 12 and can impart the function of dispersing and stabilizing the particles in the coating composition, the binder 12b is preferably a mixture of cellulose and / Or a cellulose salt. Specific examples of cellulose and / or cellulose salts include hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, carboxymethyl cellulose, and sodium salts and ammonium salts of these. Among them, it is particularly preferable to include at least one selected from the group consisting of carboxymethylcellulose and salts thereof, and hydroxyethylcellulose and salts thereof.

As a method of forming the porous layer 12 in the porous laminated film 10, a method of applying a coating liquid containing the heat-resistant particles 12a, the binder 12b, and other compositions is preferably employed. As the coating method, any generally used method may be used. For example, a coating liquid prepared by dispersing an oxylane ring-containing compound in ion-exchanged water or the like is applied to a substrate by a coating method such as a reverse coating method, a bar coating method, a gravure coating method, a rod coating method, a die coating method, Based polyolefin film 11 and dried to form the porous layer 12. Further, in the production of the coating liquid, a dispersant or the like may be appropriately added in order to prevent the heat-resistant particles 12a from segregating in the porous layer 12.

In the present embodiment, it is preferable that the air permeation resistance of the porous laminated film 10 is 50 to 500 sec / 100 ml. When the air permeation resistance is less than 50 sec / 100 ml, insulation between the electrodes can not be sufficiently maintained when the film is used as a separator, which may result in insufficient safety. When the air permeation resistance exceeds 500 sec / 100 ml, the output characteristics of the battery tend to be lowered when the film is used as a separator. The air permeation resistance of the porous laminated film 10 is preferably 80 to 350 sec / 100 ml, more preferably 150 to 250 sec / 100 ml, depending on the application.

The method of setting the air permeation resistance of the porous laminated film 10 within the above range can be effectively achieved by using the heat resistant particles 12a having the above-described shape.

The total thickness of the porous laminated film 10 is preferably 15 탆 to 40 탆, more preferably 18 탆 to 35 탆. The thickness of the porous layer 12 is preferably 1 占 퐉 to 15 占 퐉, more preferably 3 占 퐉 to 10 占 퐉, from the viewpoints of heat resistance and mechanical properties.

The heat shrinkage ratio of the porous laminated film 10 in the longitudinal direction and the transverse direction of the film at 150 캜 is preferably 0 to 3%, more preferably 0 to 2%. When the heat shrinkage ratio in the longitudinal direction and the width direction of the film at 150 DEG C is more than 3%, the film may shrink easily due to the heat generated when the film is used as a separator of a battery, There is a possibility that it can not be maintained. If the heat shrinkage ratio is less than 0%, there is a fear that the dimensional stability of the battery itself may be affected when the film is used as a separator of a battery.

In order to set the heat shrinkage ratio in the longitudinal direction and the width direction of the film at 150 DEG C within the above range, it can be effectively achieved by using the heat resistant particles 12a having the aspect ratio within the above range.

The porous laminate film 10 according to the present embodiment is obtained by laminating the porous layer 12 on at least one surface of a polyolefin porous film 11. [ When the porous layer 12 is laminated only on one side of the polyolefin-based porous film 11, the surface of the porous layer 12 on which the porous layer 12 is to be laminated is a surface of the drum (surface which was in contact with the cast drum when the cast film was produced) And a drum surface (a surface that is not in contact with the cast drum when the cast film is produced). The porous layer 12 may be laminated on both the drum surface and the drum surface of the polyolefin-based porous film 11.

Hereinafter, a method for producing the polyolefin-based porous film 11 constituting the porous laminated film 10 according to the present embodiment and a method for producing the porous laminated film 10 will be described in detail. The production method of the polyolefin-based porous film 11 used as the base material of the porous laminated film 10 is not limited to the following description. Hereinafter, a polypropylene porous film obtained by the? -End method will be described as an example.

As a polypropylene resin, 93.8 parts by mass of a commercially available homopolypropylene resin having an MFR of 8 g / 10 minutes, 1 part by mass of a high melt strength polypropylene resin having an MFR of 2.5 g / 10 minutes and a melt index of 18 g / 10 , 0.2 parts by mass of N, N'-dicyclohexyl-2,6-naphthalenedicarboxyamide was mixed with 5 parts by mass of an ultra-low density polyethylene resin prepared in Preparation Example 1, and a raw material prepared in advance at a predetermined ratio using a twin screw extruder was prepared do. At this time, the melting temperature is preferably 270 to 300 캜.

Subsequently, the mixed raw material is fed to a single-axis melt extruder, and melt extrusion is performed at 200 to 230 캜. Then, foreign matters or modified polymers are removed from the mixed material by a filter installed in the middle of the polymer tube, and the mixed raw material is discharged from the T die onto the cast drum to obtain an unstretched sheet. At this time, the surface temperature of the cast drum is preferably 105 to 130 DEG C from the viewpoint of controlling the beta fraction of the cast film to a high level. In particular, since the shaping of the end portion of the sheet affects the stretchability of the sheet, it is preferable that the spot air is sprayed to the end portion of the sheet and adhere to the cast drum. Further, in accordance with the state of adhesion of the entire sheet to the cast drum, air is sprayed to the entire sheet surface using an air knife as required, or a polymer (unstretched sheet) is applied to the cast drum It may be closely contacted.

Subsequently, the obtained unoriented sheet is biaxially oriented to form pores in the stretched film. The biaxial orientation may be performed by a sequential biaxial stretching method in which an unstretched sheet is stretched in the film length direction, then in the width direction, or in the width direction and then in the longitudinal direction, And a simultaneous biaxial stretching method in which stretching is performed at almost the same time can be used. From the standpoint of obtaining a highly speculative film, it is preferable to employ a sequential biaxial stretching method, and it is particularly preferable to stretch in the longitudinal direction and then in the width direction.

As the specific stretching condition, the temperature is controlled at first to stretch the non-stretched sheet in the longitudinal direction. As the temperature control method, a method using a temperature-controlled rotary roll, a method using a hot air oven, or the like can be adopted. As the stretching temperature in the longitudinal direction, a temperature of preferably 90 to 135 占 폚, and preferably 100 to 120 占 폚 may be employed. The preferred stretching ratio is 3 to 6 times, more preferably 4 to 5.5 times. Subsequently, the film obtained by stretching the non-stretch sheet in the longitudinal direction is once cooled, and then the end of the film is gripped and introduced into the stenter-type stretching machine. Then, the film is heated to 140 to 155 占 폚, preferably 5 to 12 times, more preferably 6 to 10 times in the width direction. At this time, the transverse stretching speed is preferably 300 to 5,000% / min, more preferably 500 to 3,000% / min. Subsequently, heat setting is carried out in the stator as it is, and the temperature is preferably not less than the transverse stretching temperature and not more than 160 캜. The heat setting may be performed while relaxing in the longitudinal direction and / or the width direction of the film, and the relaxation ratio in the width direction is preferably set to 5 to 35% from the viewpoint of thermal dimensional stability.

A coating liquid to be applied to the polyolefin-based porous film (11) produced by the above production method is produced. That is, 24.0% by mass of a water dispersion of modified polyethylene (solid content concentration of 20%), 0.6% by mass of polypropylene glycol glycidyl ether, and 0.6% by mass of carboxymethylcellulose as the heat resistant particles 12a were contained as the calcium carbonate 14.0% By mass and 60.8% by mass of ion-exchanged water are mixed. The coating solution was stirred for about 4 hours and then applied onto the polyolefin porous film 11 by a coating method using a gravure coater and dried at 100 DEG C for 1 minute to form a porous layer 12 having a thickness of 3 to 5 mu m ). Thereby, the porous laminated film 10 shown in Fig. 1 is obtained.

The porous laminated film 10 according to the present embodiment can be suitably used as a separator of a power storage device because it has excellent heat resistance, air permeability and planarity. When the porous laminated film 10 is used as a separator of an electric storage device, a coating layer may be further formed on the film 10, or mechanical processing may be performed.

Here, examples of the electrical storage device include a non-aqueous electrolyte secondary battery typified by a lithium ion secondary battery and an electric double-layer capacitor such as a lithium ion capacitor. Such a power storage device can be used repeatedly by charging and discharging, so that it can be used as a power supply device for an industrial device, a living appliance, an electric car or a hybrid electric car. The electrical storage device using the porous laminated film (10) of the present invention as a separator can be suitably used for industrial devices and power supply devices for automobiles due to excellent characteristics of the separator.

In the above, a method of providing a specific porous layer 12 on a polyolefin-based porous film 11 by coating has been described. However, in general, when a porous layer is provided on a porous film by coating, various problems exist Therefore, a method of solving them will be described below.

For example, in order to impart heat resistance to a separator for a power storage device, when a heat-resistant porous layer is formed on a deformable porous film made of polyolefin or the like by wet coating, if continuous coating is performed, In some cases, surface defects on the surface.

The planar defect on the crater ring means a depression that occurs when a liquid film is shifted on the base material to form a liquid film, or a liquid film in a certain area is repelled on the liquid film immediately after the liquid film is formed. Generally, "cratering" means that the surface of the substrate is dented to the extent that it is visible, and "dent" means that the substrate does not reach the substrate. Hereinafter, the inclusion including the pitting is referred to as a surface defect (cratering defect) on the cratering.

As a cause of the occurrence of such a cratering defect, for example, in "Coating" (Processing Technology Research Society, 2002, page 840), for example, in a coating editing board, a sudden rise in the amount of a solvent from a wet coating immediately after coating, There is a description that a trigger portion of low energy is generated on the surface of the coating film due to the influence of residual monomers and additives for paints contained therein, contamination of dust from the atmosphere, oil contamination on the coated object, and the like, and this is expanded. , A method of eliminating an emergency material in a coating composition, or a method of making the coating composition of the present invention less wettable to a base material and making it easier to wet. However, the former method has a weak effect, and the latter method largely deteriorates the durability required for a separator for a power storage device, which is originally intended, and the output performance of the power storage device is lowered.

Accordingly, a coating composition capable of coating a porous layer having heat resistance on a porous substrate which is easy to deform, in a state in which generation of surface defects on the crater ring is small, without deteriorating the air permeability of the substrate, and a process for producing a separator for a power storage device The method will be described.

Means for Solving the Problems In order to solve the above problems, the present inventors have conducted intensive studies and, as a result, have found that the following coating compositions and methods for producing separators for power storage devices using them are suitable.

(1) A coating composition comprising heat-resistant particles, a binder and a solvent, wherein the coating composition exhibits the following properties at 25 캜.

The contact angle of the solvent component to the object to be coated is 80 ° or more

Surface tension of 45 x ^10-3 N / m (hereinafter referred to as mN / m) or less

· Storage elastic modulus (G ') measured by vibration measurement at a frequency of 0.1 Hz is 0.1 Pa or more and 100 Pa or less

(2) The coating composition of (1) above, wherein the viscosity of the coating composition at a shear rate of 1,000s < ^-1 > at 25 DEG C is 10 mPa.s or more and 400 mPa.s or less.

(3) A process for producing a separator for a power storage device, wherein the coating composition of the above (1) or (2) is coated on a porous substrate and dried to form a heat resistant porous layer.

According to the above, it is possible to provide a coating composition which is applied when a porous layer having heat resistance is formed on a porous substrate which is liable to be deformed, and which can be applied in a state in which generation of surface defects such as cratering is minimized, Can be provided. In addition, it becomes possible to manufacture a separator for a power storage device having heat resistance and air permeability by the production method of coating the coating composition on a porous substrate.

This will be described in detail below.

Preferably, the coating composition contains heat-resistant particles, a binder and a solvent, and the contact angle of the solvent component contained in the coating composition with the object to be coated at 25 캜 is 80 ° or more. Here, the object to be painted refers to an object to be coated with the coating composition, and in the method for manufacturing a separator for a power storage device, it refers to a porous substrate. The solvent component means a component contained in the coating composition that is liquid at room temperature and at a constant pressure and is removed in the drying step and does not remain in the finally formed coating film. The solvent component may be one kind of solvent, have. Details of the solvent will be described later. The binder is a material which has a film-forming property by itself and can bind to other materials, and in most cases includes organic or inorganic polymer compounds and mixtures thereof.

The above-mentioned contact angle can be measured by dropping a liquid containing only the solvent component contained in the coating composition onto the object to be painted by using a general contact angle measuring device (e.g., "DM700" manufactured by Kyowa Chemical Industry Co., Ltd.) , It is possible to calculate from the droplet shape formed. Details of the measurement method will be described later.

When the angle of contact of the solvent component to the object to be coated is less than 80 °, when the object to be coated is porous, the solvent component penetrates into the hole due to the capillary force after the coating, There is a case to discard. As a result, characteristics (particularly output characteristics) of the intended separator for power storage devices are lowered, uneven shrinkage occurs in the coating and drying process, and streaks are formed. In order to adapt the contact angle to the object to be coated to this range, it is possible to select the type of the solvent appropriately.

The above-mentioned contact angle with respect to the object to be painted is more preferably 85 DEG or more, particularly preferably 90 DEG or more.

The surface tension of the coating composition at 25 캜 is preferably 40 mN / m or less.

The surface tension (?) Of the coating composition can be measured by a current method (pendant drop method). Here, the term "droplet" refers to a droplet formed at the tip of a tubule when a liquid is extruded from the tip of a tubule facing the vertical direction. Since the shape of the current enemy depends on the amount, density and surface tension of the extruded liquid, the surface tension can be calculated by analyzing the shape. Details of the measurement method will be described later.

If the surface tension of the coating composition at 25 DEG C is higher than 40 mN / m, the effect of suppressing the surface defects, particularly the cratering defects may be insufficient. The lower the surface tension of the coating composition is, the better, but the available material is limited, so the lower limit is about 15 mN / m to 20 mN / m.

In order to set the surface tension of the coating composition to be in the range of 15 mN / m to 40 mN / m, a component (so-called surface active component) which tends to be oriented in the vapor-liquid interface in the coating composition, such as an organic binder, By adjusting the kind and quantity of the particles.

The surface tension of the coating composition at 25 캜 is preferably 40 mN / m or less, more preferably 35 mN / m or less and still more preferably 30 mN / m or less.

Further, as for the viscoelasticity of the coating composition at 25 캜, it is preferable that the storage elastic modulus (G ') by vibration measurement at a frequency of 0.1 Hz is 0.1 Pa or more and 100 Pa or less.

Here, the storage modulus of a coating composition is a mathematical expression of the influence due to the elastic properties that occur when an external force is applied to the coating composition. That is, the storage elastic modulus refers to the ratio of the elastic stress at the same phase as the distortion generated when the external physical force is applied, and corresponds to the energy that can be elastically accumulated in the external force received by the coating composition. Since the occurrence of the cratering defects is considered to be due to the expansion force due to the difference in interfacial tension between the low surface energy portion of the surface of the object to be coated and the liquid film, the magnitude of the resistance to the cratering is equivalent to the storage elastic modulus The larger the value, the greater the resistance.

The storage modulus of the coating composition can be measured by a general rheometer, preferably a rheometer capable of obtaining a torque resolution of about 0.001 N to 0.01 N, and it is preferable to use a cone & plate having a diameter of 35 mm or more. Details of the measurement method will be described later.

When the storage elastic modulus (G ') is less than 0.1 Pa, the coating composition can not oppose the flow due to the expansion force due to the difference in interfacial tension, and the effect of suppressing the formation of the curing ring defect is small. On the other hand, if the storage elastic modulus (G ') is larger than 100 Pa, the leveling after the formation of the coating film becomes insufficient and the smoothness of the coating film is lowered.

In order to set the storage elastic modulus (G ') within a preferable range, the amount of the particle component in the coating composition, the surface state, the particle diameter distribution, and the component (so-called surface active component) Viscosity modifiers, dispersants, surfactants, and the like.

The storage elastic modulus (G ') measured by vibration measurement at a frequency of 0.1 Hz of the coating composition is preferably 0.1 Pa or more and 100 Pa or less, more preferably 1 Pa or more and 80 Pa or less, and still more preferably 5 Pa or more and 50 Pa or less.

Further, in order to obtain a better coated surface, the viscosity of the coating composition at a shear rate of 1,000 s ^-1 at 25 캜 is preferably 10 mPa · s or more and 400 mPa · s or less.

The viscosity at a shear rate of 1,000 s ^-1 can be measured with a common rheometer. That is, measurement can be performed by changing the measurement mode in the same apparatus as the above-mentioned measurement of the storage elastic modulus. Details of the measurement method will be described later.

When the viscosity at a shear rate of 1,000 s < ^-1 > is less than 10 mPa · s, depending on the coating method, the coating can not follow the movement of the substrate as the coating material during continuous coating, As a result of the retention of the coating liquid on the liquid portion of the substrate, defects on the stripe pattern are generated and the coated surface may be deteriorated in some cases.

On the other hand, when the viscosity at a shear rate of 1,000 s ^-1 is larger than 400 mPa · s, an air layer (also referred to as a co-current or a condensate) moving along with the substrate during continuous coating is formed between the discharge portion of the coating liquid and the substrate The liquid portion may be broken, and a coating-like defect of a streak shape may occur.

In order to make the viscosity of the coating composition at a shear rate of 1,000 s ^-1 at 10 mPa · s or more and 400 mPa · s or less, this can be achieved by controlling the amount and molecular weight of the high molecular weight component in the coating composition such as an organic binder or a thickener.

The viscosity of the coating composition at a shear rate of 1,000 s ^-1 is preferably 10 mPa · s or more and 400 mPa · s or less, more preferably 15 mPa · s or more and 350 mPa · s or less, still more preferably 20 mPa · s Or more and 300 mPa · s or less.

Hereinafter, the paint composition and the production method of a battery device separator using the same will be described in more detail.

[Paint composition]

The coating composition contains particles, a solvent and a binder in the coating composition. These may be composed of a single kind or may be composed of plural kinds, respectively. By applying this coating composition by a method described later, it is possible to obtain a separator for a power storage device having a porous layer which is excellent in heat resistance, air permeability and planarity and has less surface defects.

In the following description, the kinds of particles are distinguished according to the kinds of elements constituting the particles. For example, in nitrogen-doped titanium oxide (TiO _{2 - x} N _x ) in which a part of oxygen of titanium oxide (TiO ₂ ) and titanium oxide is replaced by nitrogen as an anion, since the elements constituting the particles are different, Of particles. In addition, particles (ZnO) made of the same element, for example Zn and O only, are particles of the same kind even if there are a plurality of particles having different particle diameters and different composition ratios of Zn and O. Even if a plurality of Zn particles having different oxidation numbers exist, the same kind of particles are the same as the elements constituting the particles (in this example, as long as the kinds of elements other than Zn are the same). Preferred types of particles will be described later.

In the following description, a solvent refers to a substance which is liquid at ordinary temperature and normal pressure, and is capable of almost completely evaporating in the drying step after coating. The kinds of the solvent will be described later.

In the following description, the binder refers to a material capable of dissolving or dispersing in the solvent and capable of binding between different materials (intergranular, particle-substrate, etc.). Generally, it is a material which can be made into a high molecular weight by a polymer material or polymerization or condensation reaction. The binder may have other functions than the above functions. Other functions include, for example, a function of dispersing and stabilizing particles in a paint composition by adsorbing to the surface of particles, a function of further enhancing the adhesion with the object to be coated, a function of adjusting the viscosity of the coating composition, And the like.

[particle]

The coating composition contains at least one kind of particles. The kind of the particles is not particularly limited, but is preferably heat-resistant particles for the purpose of imparting heat resistance. Examples of the heat resistant particles include inorganic materials such as aluminum oxide, aluminum hydroxide (including pseudoboehmite), silica, potassium titanate, wollastonite, glass fiber, titanium oxide (rutile type), calcium carbonate (calcite, aragonite) Particles, and composite oxides or mixtures thereof, thermoplastic resins having a melting point of 330 ° C or higher, or resins having substantially no melting point, such as polyimide, polyamideimide and polyetherimide. have. Of these, calcium carbonate is preferable from the viewpoint of electrical stability and shape.

In addition to the heat-resistant particles, the coating composition may contain thermoplastic resin particles having a characteristic of melting at a constant temperature. The melting temperature is within a preferred range, and the melting point is preferably 110 to 140 占 폚, more preferably 120 to 140 占 폚. The material is not particularly limited, but thermoplastic resin particles containing a polyolefin resin are preferable, and thermoplastic resin particles comprising a polyolefin resin such as polyethylene, polyethylene copolymer, polypropylene, and polypropylene copolymer are particularly preferable .

[menstruum]

The coating composition contains at least one solvent. The number of types of the solvent is preferably from 1 to 20, more preferably from 2 to 10, and still more preferably from 1 to 6.

Here, the kind of the solvent is distinguished according to the molecular structure constituting the solvent. That is, it has been found that (Stereoisomers) which have the same elemental composition and differ in the binding relationship (structural isomer) even when the kinds and number of functional groups are the same, or those which are not the above structural isomers but do not exactly overlap each other in any three- , And treated as solvents different in kind. For example, 2-propanol and n-propanol are treated as different solvents.

Since the coating composition is applied onto a porous substrate to form a porous layer, the contact angle of the solvent component to the substrate (substrate) is preferably 80 ° or more. The kind of the solvent is not particularly limited so long as this can be achieved, for example, water or a mixture of water and a polar organic solvent is preferable. Herein, the polar organic solvent refers to a solvent having a solubility in water of at least 5% at 20 캜, and examples thereof include various alcohols (methanol, ethanol, isopropanol, ethylene glycol, propylene glycol, etc.), glycol ethers (such as ethylene glycol mono Ethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate and the like), ketones (methyl ethyl ketone, diacetone alcohol, etc.) and esters (ethyl acetate etc.). As the solvent for the coating composition, a mixed solvent obtained by mixing a small amount of such a polar organic solvent with water is suitable.

[Other additives]

The coating composition may contain various additives in addition to the above-mentioned particles, binder and solvent. Examples of the additives include surfactants, leveling agents, dispersing agents, thixotropic agents, pH adjusting agents, thickening agents, preservatives, drying rate adjusting agents, antioxidants, antioxidants, antioxidants and the like, which are necessary for increasing the quality of the obtained coating film, Antioxidants, stabilizers, preservatives and the like.

[materials]

In the method for producing a battery separator for a power storage device described later, the substrate (object to be formed) for forming the porous layer is not particularly limited, but is electrochemically stable, has an air permeation resistance of 50 to 500 sec / Is preferably 60 to 90%, and specifically, a polyolefin-based porous film is preferable. Details of the polyolefin-based porous film are as described above.

[Production method of coating composition]

The coating composition is composed of at least particles, a binder and a solvent, and other additives may be mixed. The production method thereof is obtained by weighing the prescription amount of the above components in terms of mass or volume, and mixing them by stirring. At this time, dephosphorization and filtration may be performed.

The particles may be added in any form of a particle dispersion or powder. In the case of treating the powder as a raw material, it is preferable to form the particle dispersion once through a step of dispersing the particles in the liquid by various dispersing devices such as a high-pressure homogenizer, a disperser and a media mill.

There are no particular restrictions on the stirring conditions or the stirring apparatus when the coating composition is combined, and it is only necessary to be able to realize the apparatus and the rotation speed required for sufficiently mixing the liquid. Particularly, the local shear rate in the liquid is smaller than 10 ⁴ s ^-1 and the Reynolds number is in the range of 1,000 or more. This is because aggregation due to shear fracture of the particle dispersion and aggregation due to local retention, .

The order of addition of the particles, solvent, binder and other additives in the combination of the coating composition and the addition rate are not particularly limited. Preferably, a small amount of the diluted binder raw material mixed with the solvent and the other additives is added to the particle dispersion while stirring to prevent aggregation of the binder component due to adsorption on the particle surface and generation of foreign matter .

The coating composition thus obtained may be subjected to a suitable filtration treatment before coating. This suitable filtration treatment is preferably carried out, for example, by selecting a filter material and a filter scale that match the polarity of the surface of the solvent and the particle, under a pressure condition adapted to a shear rate and a filter structure that do not destroy the dispersed state of the particle dispersion Do.

[Method of Manufacturing Separator for Power Storage Device Having Porous Layer]

As a method for producing a separator for a power storage device having a porous layer using the above coating composition, first, the coating composition is applied by a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, A method of forming a coating film by coating the above-mentioned porous substrate with a die coating method (see U.S. Patent No. 2681294) is preferable. Of these coating methods, a gravure coating method or a die coating method is preferable as a coating method of the coating composition.

The gravure coating method is excellent in coating a coating composition having a small coating amount with a uniform film thickness. Particularly in the gravure coating method, it is more preferable to use a gravure roll of small diameter having a small gravure roll diameter in the Direct Gravure method in terms of ensuring the stability of the meniscus portion. As such a coating method, a micro gravure method is known.

In addition, the die coating method can control the film thickness to the amount of the supplied liquid to the coating die in a post-metering system such as a gravure coater or the like, and in principle, there is no retention portion or evaporation portion of the coating composition. It is also suitable in terms of stability. In the case of the die coating method, when the thickness of the liquid film to be coated is thin, a coating method (web pressurizing type slot die coater) in which the die lip is approached to the extent of almost touching in the state of free span , And a coating method (vacuum chamber type die coater) for applying a back pressure to the upstream side of the bead (liquid-filled portion).

Subsequently, the coated film formed on the substrate is dried by a coating process. The drying conditions are such that when the base material does not cause shrinkage due to softening and the binder component sufficiently bonds with the particles and when the coating composition contains thermoplastic particles, if the temperature is within a range where the thermoplastic particles do not melt, Is not particularly limited.

Examples of the drying method include dry heat drying (adhesion to a hot object), convection heat (hot wind), radiation heat (infrared light), and other methods (microwave, induction heating, etc.). Among them, in the above-described production method, it is preferable to use convection heat transfer or radiation heat transfer since the drying speed in the width direction needs to be precisely uniform. Further, in the fast rate drying period, in order to achieve a uniform drying rate in the width direction, in the case of employing the drying method by convective heat transfer, it is desirable to lower the overall material transfer coefficient at the time of drying while maintaining a controllable air velocity It is preferable to use a possible method. Concretely, a method of blowing hot air in parallel to the supporting base material and in a direction parallel or perpendicular to the carrying direction of the base material may be used.

Example

Hereinafter, the present invention will be described in detail by way of examples.

As Examples 1 to 30 and Comparative Examples 1 to 5, a porous laminated film in which a porous layer was formed on a polyolefin-based porous film as a base material by using the following paint compositions 1 to 34 was produced. Further, a battery device using each of the porous laminated films as a battery separator was produced. The properties of the porous laminated film and the electrical storage device in each of the examples and comparative examples were measured or evaluated by the following methods.

(1) Average particle diameter of heat resistant particles

The particle diameter of the heat-resistant particles was measured using a laser diffraction scattering particle size analyzer ("LMS-300" manufactured by Seishin Enterprise Co., Ltd.). The particle diameter corresponding to the 50% number-based integrated value in the number-based integral curve for the obtained particle diameter was defined as the average particle diameter.

(2) Aspect ratio, cross-sectional shape,

Using a scanning electron microscope (SEM), photographs were taken at a magnification of 20,000 times of the heat-resistant particles randomly extracted. A cross-sectional projection image of the heat-resistant particles was formed by image analysis using image analysis software ("MacView ver 4.0" manufactured by Mantec Co., Ltd.).

From the cross-sectional image, the radius (Rl) of the minimum circumscribed circle and the radius (Rs) of the maximum inscribed circle were determined (see Fig. 1) to calculate the variance Ps defined by the equation (1). The cross-sectional images were prepared for 100 heat-resistant particles randomly extracted, and the average value of the degree of dissociation (Ps) of each heat-resistant particle determined from the obtained cross-sectional image was taken as the degree of dissociation (Ps) of the heat-resistant particle.

Ps = Rl / Rs ... (One)

Further, the maximum length (long diameter) and the minimum length (short diameter) of each heat resistant particle were determined from the photograph taken at 20,000 times and the cross-sectional image, and the aspect ratio defined by equation (7) was calculated. The aspect ratio was determined for 100 heat-resistant particles, and the average was defined as the aspect ratio of the heat-resistant particles.

Aspect ratio = maximum length in heat-resistant particles / minimum length in heat-resistant particles ... (7)

(3) The thickness of the polyolefin-based porous film and the thickness of the porous layer

The polyolefin-based porous film was fixed on a sample table of a scanning electron microscope and was subjected to measurement with a sputtering apparatus under conditions of a vacuum of 10 ^-3 Torr, a voltage of 0.25 KV and a current of 12.5 mA for 10 minutes , An ion etching treatment was performed to cut the cross section, and gold sputtering was performed on the surface of the film by a copper sputtering apparatus. Then, the film was observed at a magnification of 3,000 times using a scanning electron microscope.

The thickness (la) of the polyolefin porous film and the thickness (lb) of the porous layer were measured from the image obtained by observation. In the sample used for the measurement of the thickness, 10 places were arbitrarily selected at intervals of at least 5 cm in the longitudinal direction of the film, and the average of the ten measured values was taken as the thickness (la) of the polyolefin- And the thickness (lb) of the porous layer.

(4) Air permeation resistance

A square having a length of 100 mm on one side was cut out from a polyolefin porous film or a porous laminated film to prepare a sample and a B type Gurley tester of JIS P 8117 (2009) Was measured three times. The average value of the permeation time by three measurements was regarded as the air permeation resistance of the polyolefin-based porous film or the porous laminated film.

The air permeation resistance of the polyolefin-based porous film was measured by attaching a PP tape (made by Sumitomo 3M Co., Ltd., 313D) having a width of 65 mm to the porous laminated film and peeling the same to remove the porous layer from the porous laminated film Polyolefin-based porous film).

(5) Heat shrinkage

The porous laminated film was cut into a rectangle having a length of 150 mm and a width of 10 mm in the longitudinal direction and the width direction, to obtain a sample. A sample was placed at intervals of 100 mm, hanging 3 g of the weight, placed in a hot air oven heated to 150 캜 for 40 minutes, and subjected to heat treatment. After the heat treatment, it was allowed to cool, and the distance between the marks was measured. The heat shrinkage was calculated from the change in the distance between the marks before and after the heating, and the heat shrinkage was regarded as an index of the dimensional stability. The measurement was carried out by 5 samples for each direction in the longitudinal direction and the width direction with respect to each of the porous laminated films, and the evaluation was made by an average value.

(6) Planarity

As shown in Fig. 7, a porous laminated film was placed on two rolls 4 arranged in parallel at intervals of 3 m, one end was fixed to the fixed end 5, and the other end was provided with a weight 6 of 1.7 kg And a load was applied so as to be uniform in the width direction of the film. In this state, the cross-sectional shape in the width direction in the center portion 7 of the two rolls 4 (the displacement when the film surface was superimposed along the central portion 7) was recorded. The difference between the highest position and the lowest position of the cross-sectional shape of the film was measured as an elongated amount, and evaluation was made according to the following criteria. The closer to zero the elongation amount indicates the better the planarity of the film.

AA: Less than 3mm

A: Less than 3mm and less than 5mm

B: Slender amount 5mm or more and less than 15mm

C: 15 mm or more

(7) Battery evaluation

(safety)

A nickel (Ni) plate having a thickness of 40 탆 was punched out into a circle having a diameter of 15.9 mm. Further, the porous laminated film was punched into a circle having a diameter of 24 mm. Subsequently, a Ni plate, 1 mg of metal particles (aluminum particle "Alfa" made by Aesar, average particle diameter: 11 μm), a porous laminated film and an Ni plate were stacked in this order from the bottom to form a stainless steel metallic container HS cell manufactured by Honsen Co., Ltd., spring pressure: 5 kgf). Further, the container and the cover are insulated, and the container and the cover are in contact with the Ni plate. An electrolytic solution prepared by dissolving LiPF ₆ as a solute in a concentration of 1 mol / liter in a mixed solvent of propylene carbonate: diethyl carbonate = 3: 7 (volume ratio) was injected into this vessel and sealed to produce a pseudo battery Respectively.

This pseudo battery was connected to a thermocouple connected to an electric resistance measuring device (LCR HiTester 3522-50, manufactured by Hioki Electric Co., Ltd.) and a thermometer, and the temperature was changed from 25 DEG C to 200 DEG C at 2 DEG C / min Lt; / RTI > Then, the temperature and the electrical resistance were continuously measured, and the temperature when the electrical resistance value became 0? (That is, the film was broken) was examined and evaluated according to the following criteria. In addition, the number of tests was 10, and the evaluation was carried out with the average value of ten measurement values, and the evaluation of C was rejected.

A: The temperature at which the electric resistance value becomes 0? Is 200 占 폚 or more

B: Temperature at which the electric resistance value becomes 0? Is 150 占 폚 or more and less than 200 占 폚

C: Temperature at which the electric resistance value becomes 0? Is less than 150 占

(Output characteristics and cycle characteristics)

(Positive electrode) of lithium cobalt oxide (LiCoO ₂ ) having a thickness of 40 탆 was punched out into a circle having a diameter of 15.9 mm. Further, a graphite anode (made by Hosens) having a thickness of 50 mu m was punched out into a circle having a diameter of 16.2 mm. Further, the porous laminated film was punched with a diameter of 24 mm. Then, the negative electrode, the porous laminated film and the positive electrode were stacked in this order from below in such a manner that the positive electrode active material and the negative electrode active material surface were opposed to each other and placed in a lid stainless steel metal container (HS cell, spring pressure: 1 kgf) Respectively. Further, the container and the lid are insulated, the container is in contact with the copper foil of the negative electrode, and the lid is in contact with the aluminum foil of the positive electrode. An electrolytic solution prepared by dissolving LiPF ₆ as a solute in a concentration of 1 mol / liter in a mixed solvent of propylene carbonate: diethyl carbonate = 3: 7 (volume ratio) was injected into this container and sealed to prepare a battery .

The prepared battery was charged 4 times to 2 V at 3 mA in an atmosphere of 25 캜 for 2 hours and discharged at 3 mA to 2.7 V and then charged to 3 V for 2 hours at 3 mA, Discharge operation of discharging at 3 mA to 2.5 V was carried out, and a discharging capacity of 3 mA was examined. Charging was performed at 3 mA for 2 hours up to 4.2 V, and discharging was performed at 40 mA to 2.5 V to measure a discharge capacity of 40 mA. Then, the output characteristics given by equation (8) were evaluated based on the following criteria. In addition, the number of tests was 10, and the evaluation was carried out with an average value of 10 measured values.

Output characteristic = [(discharge capacity of 40 mA) / (discharge capacity of 3 mA)] x 100 ... (8)

AA: 85% or more

A: 70% or more and less than 85%

B: 60% or more and less than 70%

C: less than 60%

The battery thus prepared was charged at 3 mA to 4.2 V for 2 hours under an atmosphere of 25 캜 and discharged at 3 mA until 2.7 V was repeated four times and then charged at 3 mA to 4.2 V for 2 hours And the discharge capacity was measured when discharging was performed up to 2.7 V at 3 mA. Thereafter, the operation of charging the battery at 10 mA to 4.2 V for 30 minutes and discharging at 10 mA to 2.7 V was repeated 300 times under the atmosphere of 50 캜, and the discharge capacity at the 300th charge and discharge was measured. The cycle characteristics given by the equation (9) were evaluated by the following criteria. In addition, the number of tests was 10, and the evaluation was carried out with the average value of ten measured values, and the evaluation of C was rejected.

Cycle characteristic = [(discharge capacity of 300th time / discharge capacity of first time) 占 300] (9)

A: 90% or more

B: 70% or more and less than 90%

C: Less than 70% or more than 1% is less than 20%

(8) Surface defects (cratering)

With respect to 20 separators for power storage devices obtained by molding the porous laminated film into A4 size, the surface on which the porous layer was formed was visually checked for defects using a transmission light source, and the defects were circular in shape, And the defect having a diameter of the circumscribed circle of the defect portion of 1 mm or more was counted as a cratering defect. The number of defects per one separator of the above-mentioned size was obtained, and the following class division was carried out, and three or more points were passed.

5 points: Number of surface defects less than 1

4 points: Number of surface defects 1 to 3

3 points: Number of surface defects 3 or more and less than 5

2 points: Number of surface defects 5 or more and less than 10

1 point: Number of surface defects 10 or more

(9) Surface defects (streaked)

With respect to 20 separators for power storage devices obtained by molding the porous laminated film into an A4 size, the surface on which the porous layer was formed was visually checked for defects by a transmission light source, and the defects were in a striped pattern in a direction parallel to the coating direction Defects having a stripe width of 1 mm or more and a length of 4 cm or more were counted as stripe-like defects. The number of defects per three separators of the above-mentioned size was obtained, and the following class division was performed, and three or more points were determined as acceptable.

5 points: Number of surface defects less than 1

4 points: Number of surface defects 1 to 3

3 points: Number of surface defects 3 or more and less than 5

2 points: Number of surface defects 5 or more and less than 10

1 point: Number of surface defects 10 or more

(10) Storage elastic modulus (G ') of the coating composition

The storage elastic modulus (G ') of the coating composition was measured as follows.

As a measuring device, a rheometer "AR1000" manufactured by T.A. Instrument Japan Co., Ltd. was used, and a cone & plate having a diameter of 40 mm and an angle of 2 was used for measurement geometry. In order to eliminate the influence of the set of the solution on the apparatus, the prepared coating composition was subjected to a pretreatment in which shearing was applied for 100 seconds at a shear rate of 100 s < ^-1 >

The measurement was carried out at 25 占 폚 in a range of stress from 0.01 Pa to 300 Pa, with the measurement frequency set to 0.1 Hz in the stress and sweep mode of the apparatus. From the data of this measurement result, it is judged that a region having a change in storage elastic modulus (G ') within 3% with respect to a change in stress is regarded as a region having a linearity, and a value at a stress 0.1 Pa And the elastic modulus (G ').

(11) Surface tension (?) Of the coating composition

1 to 5 mu L of the coating composition was extruded by a stainless steel syringe needle under an environment of 25 DEG C using a fully automatic contact angle meter ("DM-700" manufactured by Kyowa Chemical Industry Co., Ltd.) The shape of the droplet was calculated by the attached multifunctional integrated analysis software "FAMAS" according to the method described in "FAMAS Instruction Manual". The density of the compound is required as a parameter required for calculation. The density of the compound was measured using a density ratio meter (DA-130N manufactured by Kyoto Denshi Kogyo Co., Ltd.) under an environment of 25 占 폚.

(12) Contact angle of the solvent component to the substrate

1 to 2 [mu] L of the solvent component of the coating composition was applied to the support substrate (1) using a stainless steel syringe needle under an environment of 25 DEG C using an automatic contact angle meter ("DM-700" manufactured by Kyowa Kaimen Kagaku Kabushiki Kaisha) And the contact angle was measured.

(13) Shear viscosity of the coating composition

The shear viscosity of the coating composition was measured as follows.

As the measuring apparatus, the same apparatus as used in the measurement of the storage elastic modulus (G ') was used. The measurement was carried out at a measurement temperature of 25 占 폚 by measuring the steady flow in which the shear rate was changed stepwise. Specifically, after preliminary shearing at a shear rate of 100 s ^-1 for 10 seconds, step measurement was performed at three shearing points at a logarithmic spacing per one digit from 0.1 s ^-1 at a shear rate of 1,000 s ^-1 . From this data, the viscosity at a shear rate of 1,000 s ^-1 was determined.

(14) β-fixability of polyolefin-based porous film and porous laminated film

5 mg of the resin or the porous laminate film and the polyolefin porous film itself constituting the polyolefin porous film were sampled in a pan made of aluminum and measured using a differential scanning calorimeter ("RDC220" manufactured by Seiko Denshi Kogyo Co., Ltd.) . First, the temperature was raised from the room temperature to 280 ° C in a nitrogen atmosphere at 10 ° C / min (first run), held for 10 minutes, and then cooled to 30 ° C at 10 ° C / min. After holding for 5 minutes in this state, the melting peak observed when the temperature was again raised to 10 ° C / min (second run) was measured to prepare a graph. The? -Defined melting peak having a peak in a temperature range of 145 to 157 占 폚 is defined as? -Defined melting peak, and the? -Defined melting peak having a peak observed at 158 占 폚 or more is defined as a? (3), when the heat of fusion is defined as? H ?, and the heat of fusion defined as? Is defined as? H ?. Calibration of the heat of fusion was carried out using indium.

? correction ability (%) = [? H? / (? H? +? H?)] 100 ... (3)

(15) Surface pore size and surface void ratio of polyolefin-based porous film

Gold sputtering was performed on the surface of the polyolefin porous film fixed on the sample stage of the scanning electron microscope using a sputtering apparatus, and observed with a scanning electron microscope at a magnification of 10,000 times. The obtained observation image was analyzed by an image analysis apparatus, and the maximum length and minimum length in the shape of the void portion by the hole on the surface were determined, and the average value was defined as the hole diameter. The pore diameter was determined for 100 holes in the observation image by the above operation.

(A) the number of pores having an average pore diameter of not less than 0.01 μm and less than 0.5 μm and (B) the number of pores having an average pore diameter of not less than 0.5 μm and less than 10 μm, And calculated for each sample.

Surface area ratio = (A) / (B) ... (10)

(16) Melting point of binder

The binder was measured in an untreated state in the case of powder and 5 mg in a state of being dried in an oven at 50 캜 in a dispersed state, and collected in a pan made of aluminum. Using a differential scanning calorimeter ("RDC220" manufactured by Seiko Denshi Co., Ltd.), the temperature was raised from the room temperature to 280 ° C at a rate of 10 ° C / minute under a nitrogen atmosphere (first run), held for 10 minutes, / Min. After maintaining the state for 5 minutes, the melting peak observed when the temperature was raised to 10 ° C / min again (second run) was defined as the melting point of the binder.

(17) Whether or not the binder in the porous layer is melted

The porous laminated film was fixed to a specimen stage of a scanning electron microscope with the porous layer side as an upper surface, and gold sputtering was carried out using a sputtering apparatus. Observation images were taken at a magnification of 70,000 with a scanning electron microscope. The presence or absence of the particulate matter was evaluated with respect to the non-heat-resistant particle in the obtained observation image.

A: No particulate matter

B: In the granular material

(18) Dropping of heat resistant particles

The porous laminated film was cut into a tape having a width of 1 cm to prepare a sample. This sample was run in an atmosphere of 23 ° C and 50% RH in a tape runability tester ("TBT-300" manufactured by Yokohama System Laboratories) to obtain a friction coefficient (μk). The sample was installed such that the porous layer side was in contact with the guide of the testing machine. Further, the guide diameter is 6 mm?, The guide material is SUS27 (surface roughness 0.2S), the winding angle is 90 占 running speed is 3.3 cm / sec, and 1 to 50 repetitions. By this measurement, the friction coefficient K1 of the first repetition number of times and the friction coefficient K50 of the repetition times of the 50th repetition number were calculated, and the rate of change K (%) of the friction coefficient given by the equation (6) was calculated. The film running property by the repeated test was evaluated on the basis of the following criteria, and the evaluation of C was rejected.

K (%) = (K50) / (K1) x100 (6)

A: Less than 300% change rate

B: Change rate 300% or more and less than 500%

C: 500% or more change rate

[Preparation of Coating Compositions 1 to 34]

The coating compositions 1 to 34 used in Examples 1 to 30 and Comparative Examples 1 to 5 were prepared as follows.

[Coating composition 1]

As the coating composition 1 used in Example 1, heat-resistant particles, a part of a binder and a solvent component in the following materials were dispersed for 4 hours using a planetary ball mill ("P-4 type" manufactured by Fritz). Subsequently, the remaining raw materials were added to the particle dispersion and mixed while stirring. Further, this mixture was sieved by a nylon mesh having a graduation of 100 탆 to remove the coarse particles, and then, using a cartridge filter capable of collecting at a filtration efficiency of 99.9% of particles having a particle diameter of 20 탆, To a pressure within 0.1 MPa to obtain Coating Composition 1.

Heat-resistant particles: Calcium carbonate 9.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion exchange water 40.8 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 49.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of Coating Composition 1 is 100% water.

[Coating composition 2]

The coating composition 2 used in Example 2 was combined in the same manner as the coating composition 1 using the following materials.

Heat-resistant particles: Calcium carbonate 10.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion exchange water 44.8 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 44.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of Coating Composition 2 is 100% water.

[Coating composition 3]

The coating composition 3 used in Example 3 was combined using the following materials in the same manner as the coating composition 1.

Heat-resistant particles: calcium carbonate 15.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.9 mass%

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 17.2 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 66.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.9 mass% of compound containing oxirane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of Coating Composition 3 is 100% water.

[Coating Composition 4]

The coating compositions 4 used in Examples 4 and 30 were combined in the same manner as the coating composition 1 using the following materials.

Heat-resistant particles: calcium carbonate 14.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 60.8 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 24.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of Coating Composition 4 is 100% water.

[Coating composition 5]

The coating composition 5 used in Example 5 was combined in the same manner as the coating composition 1 using the following materials.

Heat-resistant particles: calcium carbonate 14.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion exchange water 50.8 mass%

Solvent component: Isopropyl alcohol 10.0 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 24.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 5 is 12.5% by mass of isopropyl alcohol and 87.5% by mass of water.

[Coating composition 6]

The coating composition 6 used in Example 6 was combined in the same manner as the coating composition 1 using the following materials.

Heat-resistant particles: calcium carbonate 14.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 57.8 mass%

Solvent component: isopropyl alcohol 3.0% by mass

Binder: Modified polyethylene water dispersion (modified polyethylene A) 24.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of Coating Composition 6 is 3.75% by mass of isopropyl alcohol and 96.25% by mass of water.

[Coating composition 7]

The coating composition 7 used in Example 7 was combined in the same manner as the coating composition 1 using the following materials.

Heat-resistant particles: calcium carbonate 14.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 57.8 mass%

Solvent component: ethyl acetate 3.0 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 24.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 7 is 3.75% by mass of ethyl acetate and 96.25% by mass of water.

[Paint composition 8]

The coating composition 8 used in Example 8 was combined in the same manner as the coating composition 1 using the following materials.

Heat-resistant particles: calcium carbonate 14.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 60.7 mass%

Surfactant: 0.1% by mass of fluorochemical surfactant

(Megafax F-533, manufactured by DIC Corporation)

Binder: Modified polyethylene water dispersion (modified polyethylene A) 24.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of Coating Composition 8 is 100% water.

[Coating composition 9]

The coating composition 9 used in Example 9 was combined using the following materials in the same manner as the coating composition 1.

Heat-resistant particles: calcium carbonate 14.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 60.7 mass%

Surfactant: Polydimethylsiloxane surfactant 0.1 mass%

("BYK 378" manufactured by Big Chemie Japan KK)

Binder: Modified polyethylene water dispersion (modified polyethylene A) 24.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacor X-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 9 is 100% of water.

[Coating composition 10]

The coating composition 10 used in Example 10 was combined in the same manner as the coating composition 1 using the following materials.

Heat-resistant particles: calcium carbonate 14.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 60.3 mass%

Surfactant: 0.5% by mass of a fluorinated surfactant

(Megafax F-533, manufactured by DIC Corporation)

Binder: Modified polyethylene water dispersion (modified polyethylene A) 24.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 10 is 100% of water.

[Paint composition 11]

The coating composition 11 used in Example 11 was combined in the same manner as the coating composition 1 using the following materials.

Heat-resistant particles: calcium carbonate 7.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.3% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 80.3 mass%

Surfactant: 0.1% by mass of fluorochemical surfactant

(Megafax F-533, manufactured by DIC Corporation)

Binder: Modified polyethylene water dispersion (modified polyethylene A) 12.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: Compound containing oxycane ring 0.3 mass%

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 11 is 100% of water.

[Coating composition 12]

The coating composition 12 used in Example 12 was combined in the same manner as the coating composition 1 using the following materials.

Heat-resistant particles: calcium carbonate 10.5 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.45 mass%

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 70.5 mass%

Surfactant: 0.1% by mass of fluorochemical surfactant

(Megafax F-533, manufactured by DIC Corporation)

Binder: Modified polyethylene water dispersion (modified polyethylene A) 18.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: Compound containing oxycane ring 0.45 mass%

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 12 is 100% of water.

[Coating Composition 13]

The coating composition 13 used in Example 13 was combined in the same manner as the coating composition 1 by using the following materials.

Heat-resistant particles: Calcium carbonate 21.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.9 mass%

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 41.1 mass%

Surfactant: 0.1% by mass of fluorochemical surfactant

(Megafax F-533, manufactured by DIC Corporation)

Binder: Modified polyethylene water dispersion (modified polyethylene A) 36.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.9 mass% of compound containing oxirane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 13 is 100% water.

[Coating Composition 14]

The coating composition 14 used in Example 14 was combined using the following materials in the same manner as the coating composition 1.

Heat-resistant particles: calcium carbonate 28.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 1.2 mass%

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 21.5 mass%

Surfactant: 0.1% by mass of fluorochemical surfactant

(Megafax F-533, manufactured by DIC Corporation)

Binder: Modified polyethylene water dispersion (modified polyethylene A) 48.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: Compound containing oxirane ring 1.2 mass%

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 14 is 100% of water.

[Paint Composition 16]

The coating composition 16 used in Example 16 was combined with the following materials in the same manner as the coating composition 1.

Heat-resistant particles: calcium carbonate 14.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 72.8 mass%

Binder: PVDF dispersion 12.0 mass%

(Solid content concentration: 40 mass%, melting point of resin: 160 占 폚) manufactured by Arkema Inc.)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 16 is 100% of water.

[Paint composition 17]

The coating composition 17 used in Example 17 was combined in the same manner as the coating composition 1 using the following materials.

Heat-resistant particles: calcium carbonate 14.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 60.8 mass%

Binder: EVA aqueous dispersion 24.0 mass%

(Sumitaflex 900HL made by Sumitomo Chemical Co., solid content concentration: 20 mass%, melting point of resin: 50 占 폚)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 17 is 100% of water.

[Paint Composition 18]

The coating composition 18 used in Example 18 was combined in the same manner as the coating composition 1 using the following materials.

Heat-resistant particles: calcium carbonate 17.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 72.8 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 9.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 18 is 100% of water.

[Paint composition 19]

The coating composition 19 used in Example 19 was combined with the following materials in the same manner as the coating composition 1.

Heat-resistant particles: calcium carbonate 8.5 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.3% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 86.4 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 5.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: Compound containing oxycane ring 0.3 mass%

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 19 is 100% of water.

[Paint composition 20]

The coating composition 20 used in Example 20 was combined in the same manner as the coating composition 1 by using the following materials.

Heat-resistant particles: calcium carbonate 18.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 76.8 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 4.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 20 is 100% of water.

[Paint Composition 21]

The coating composition 21 used in Example 21 was combined in the same manner as the coating composition 1 using the following materials.

Heat-resistant particles: Calcium carbonate 9.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion exchange water 48.8 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 39.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

Thermoplastic resin fine particles: 2.0% by mass of polyethylene particle water dispersion < RTI ID = 0.0 >

("Chemipearl W-100" manufactured by Mitsui Chemicals, Inc.)

The solvent composition of the coating composition 21 is 100% of water.

[Paint composition 22]

The coating composition 22 used in Example 22 was combined in the same manner as the coating composition 1 using the following materials.

Heat-resistant particles: Calcium carbonate 7.4 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 54.4 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 32.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

Thermoplastic resin fine particles: polyethylene particle aqueous dispersion 5.0 mass%

("Chemipearl W-100" manufactured by Mitsui Chemicals, Inc.)

The solvent composition of the coating composition 22 is 100% water.

[Paint Composition 23]

The coating composition 23 used in Example 23 was combined in the same manner as the coating composition 1 using the following materials.

Heat-resistant particles: calcium carbonate 14.0 mass%

("Tama Pearl TP-121" manufactured by Okudama Kogyo Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 60.8 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 24.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 23 is 100% of water.

[Paint composition 24]

The coating composition 24 used in Example 24 was combined in the same manner as the coating composition 1 using the following materials.

Heat-resistant particles: Pseudoboehmite (manufactured by Nikkiso Catalysts Co., Ltd.) 14.0 mass%

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 60.8 mass%

Binder: Modified polyethylene aqueous dispersion 24.0 mass%

(ARROBASE SE-1010, manufactured by Unitika Co., Ltd., solid content concentration: 20% by mass)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 24 is 100% of water.

[Paint composition 25]

The coating composition 25 used in Comparative Example 1 was combined with the following materials in the same manner as the coating composition 1.

Heat-resistant particles: wollastonite (manufactured by Harada Industries Co., Ltd.) 14.0 mass%

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 60.8 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 24.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 25 is 100% of water.

[Paint composition 26]

The coating composition 26 used in Comparative Example 2 was combined in the same manner as the coating composition 1 by using the following materials.

Heat-resistant particles: potassium titanate 14.0 mass%

("Tisumo D" made by Otsuka Chemical Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 60.8 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 24.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of Coating Composition 26 is 100% water.

[Paint composition 27]

The coating composition 27 used in Comparative Example 3 was combined with the following materials in the same manner as the coating composition 1.

Heat-resistant particles: calcium carbonate 14.0 mass%

("P-50" manufactured by Toyo Fine Chemicals Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 60.8 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 24.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 27 is 100% of water.

[Coating composition 28]

The coating composition 28 used in Comparative Example 4 was combined in the same manner as the coating composition 1 by using the following materials.

Heat-resistant particles: silica 14.0 mass%

("Saarisia 350" manufactured by Fuji Silicia Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 60.8 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 24.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 28 is 100% water.

[Paint Composition 29]

The coating composition 29 used in Comparative Example 5 was combined in the same manner as the coating composition 1 by using the following materials.

Heat-resistant particles: Alumina silicate 14.0 mass%

("Opti White MX" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 60.8 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 24.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 29 is 100% of water.

[Coating Composition 30]

The coating composition 30 used in Example 25 was combined in the same manner as the coating composition 1 using the following materials.

Heat-resistant particles: calcium carbonate 14.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 60.8 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene B) 24.0 mass%

("Chemipearl M-200" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 90 DEG C)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 30 is 100% water.

[Coating composition 31]

The paint composition 31 used in Example 26 was combined in the same manner as the paint composition 1 using the following materials.

Heat-resistant particles: calcium carbonate 14.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 60.8 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene C) 24.0 mass%

(Solid content concentration: 20 mass%, melting point of resin: 95 deg. C, manufactured by Chukyo Co., Ltd.)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 31 is 100% water.

[Paint composition 32]

The paint composition 32 used in Example 27 was combined in the same manner as the paint composition 1 using the following materials.

Heat-resistant particles: calcium carbonate 14.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 60.8 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene D) 24.0 mass%

("Chemipur W-310" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 147 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the paint composition 32 is 100% water.

[Paint composition 33]

The paint composition 33 used in Example 28 was combined in the same manner as the paint composition 1 using the following materials.

Heat-resistant particles: calcium carbonate 14.0 mass%

("PC" manufactured by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 60.8 mass%

Binder: Modified polypropylene water dispersion (modified polypropylene) 24.0 mass%

(&Quot; Chemipearl WP-100 "manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid content concentration of 20%, melting point of the resin: 158 DEG C)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the paint composition 33 is 100% water.

[Coating Composition 34]

The coating composition 34 used in Example 29 was combined with the following materials in the same manner as the coating composition 1.

Heat-resistant particles: calcium carbonate 14.0 mass%

(Finely divided particles of "PC " made by Shiraishi Calcium Co., Ltd.)

Binder: Carboxymethylcellulose 0.6% by mass

("CMC die cell 2200" manufactured by Daicel Chemical Industries, Ltd.)

Solvent component: ion-exchanged water 60.8 mass%

Binder: Modified polyethylene water dispersion (modified polyethylene A) 24.0 mass%

("Chemipearl S-100" manufactured by Mitsui Chemicals, Inc., water-diluted product having a solid concentration of 20%, melting point of the resin: 85 캜)

Binder: 0.6 mass% of compound containing oxycane ring

("Denacol EX-930" manufactured by Nagase Kasei Kogyo Co., Ltd.)

The solvent composition of the coating composition 34 is 100% of water.

The method of producing finely divided particles used in the coating composition 34 is shown below.

(Calcium carbonate (PC) manufactured by Shiraishi Calcium Co., Ltd., primary particle size: 3.2 占 퐉) was subjected to dispersion treatment using a jet mill (LMZ made by Ashizawa Finetech Co., Ltd.) Finely divided particles were obtained. Dispersion conditions were as follows: a charging amount: 500 ml, a circulation frequency: 10 times / hr, a bead diameter: 0.5 mm (bead material: zirconia).

[Production method of polyolefin-based porous film]

The production method of the polyolefin-based porous film A used in Examples 1 to 29 and Comparative Examples 1 to 5 is shown below.

94.45% by mass of homopolypropylene ("FLX80E4" manufactured by Sumitomo Chemical Co., Ltd., hereinafter referred to as PP-1) as the raw material resin of the polyolefin-based porous film, an ethylene-octene- 5% by mass), N, N'-dicyclohexyl-2,6-naphthalenedicarboxamide (Shin Nippon Rika Co., Ltd. ), 0.1% by mass of "IRGANOX 1010", and 0.1% by mass of "IRGAFOS 168" in an amount of 0.3% by mass, the antioxidant Ciba Specialty Chemicals "IRGANOX 1010" A raw material was fed from a weighing hopper to a twin-screw extruder, melt-kneaded at 300 占 폚, discharged from a die onto a strand, cooled and solidified in a water bath at 25 占 폚 and cut into chips to obtain a chip raw material.

The chips were supplied to a single screw extruder and subjected to melt extrusion at 220 DEG C. After removing foreign matters with a sintered filter of 25 mu m cut, the molten material was discharged from a T die to a cast drum controlled at a surface temperature of 120 DEG C, Cast for 15 seconds to obtain an unstretched sheet (film). Subsequently, preheating was performed using a ceramic roll heated to 120 占 폚, and the film was stretched 4.5 times in the longitudinal direction. After the film was once cooled, an end portion of the film was introduced into a tenter-type stretching machine while holding it with a clip, and the film was stretched 6 times at 145 占 폚. A relaxation of 10% in the width direction was applied to the film, and a heat treatment was performed at 155 캜 for 6 seconds to obtain a porous film having a thickness of 23 탆. The air permeability of the obtained porous film was 221s / 100ml, the average void ratio of the surface was 1.0, and the β-fixability was 75%.

A method for producing the polyolefin-based porous film B used in Example 30 is shown below.

51.85% by mass of polypropylene (FLX80E4 manufactured by Sumitomo Chemical Co., Ltd.), 47.8% by mass of propylene copolymer (Tafmer XM manufactured by Mitsui Chemical Co., Ltd.), IRGANOX 1010 by Ciba Specialty Chemicals Co., , 0.1% by mass of "IRGAFOS 168", 0.1% by mass of "IRGAFOS 168" and 0.1% by mass of calcium stearate were mixed and mixed with a Henschel mixer (trade name) Kneaded, discharged from the die into a strand, cooled and solidified in a water bath at 25 DEG C, and cut into chips to obtain a chip raw material.

This chip material was supplied to a 20 mm extruder equipped with a T-die having a lip width of 120 mm, melted at an extrusion temperature of 280 占 폚 and a discharge rate of 4 kg / h, extruded from the lip of the T die to form a film, And the noncontact surface with the drum was solidified while being air-cooled by an air knife to prepare an unoriented sheet having a width of 100 mm and a thickness of 200 mu m. The undrawn sheet was stretched in the transverse direction (TD direction) under the conditions of a stretching temperature of 23 DEG C, a strain rate of 200% / sec, and a draw ratio of 5.5 while restraining the longitudinal direction (MD direction) using a film stretcher (MD direction) at a stretching temperature of 100 占 폚, a strain rate of 1,000% / sec and a stretching magnification of 5 times to obtain a polyolefin porous film having a thickness of 15 占 퐉. The obtained porous film had an air permeation resistance of 230 s / 100 ml, an average pore size of the surface of 8.5, and a pore-forming ability of 30% or less.

[Method of forming separator for power storage device having porous layer]

In Examples 1 to 29 and Comparative Examples 1 to 5, the polyolefin-based porous film A was used as the substrate. In Example 30, the polyolefin-based porous film B was used as a substrate. The coating compositions 1 to 34 were defoamed on these substrates using a rotating-coin type defoaming device ("ARE-500" manufactured by Shin-Etsu Kabushiki Kaisha) and then subjected to continuous coating with a die coater at a conveying speed of 10 m / Was coated on the substrate under the condition that the film thickness after drying was 5 占 퐉. After the coating, drying was continuously performed under the following conditions to obtain a separator for a power storage device having a porous layer.

Blowing Temperature and Humidity: Temperature 100 ℃, Relative Humidity 1%

Wind speed: 5m / s on the coated side, 5m / s on the semi-closed side

Wind direction: perpendicular to the coating side substrate, semi-open side: perpendicular to the substrate

Drying time: 1 minute

In addition, the wind speed was measured by a hot-wire anemometer (MODEL 6034, Anemomaster wind speed and air volume meter manufactured by CANOMAX Co., Ltd., Japan).

The measurement and evaluation results of the porous laminated film of Examples 1 to 30 and Comparative Examples 1 to 5 and the separator for power storage device manufactured by the above method are as follows.

As described above, in the porous laminated film according to the present embodiment, heat resistance can be imparted by forming the porous layer in the polyolefin porous film, and the planarity and the decrease in air permeation resistance can be suppressed. Such a porous laminated film can be appropriately used as a separator for various power storage devices such as a lithium ion battery, for example, a nonaqueous electrolyte secondary battery. When the porous laminated film according to the present embodiment is used as a separator, it is possible to achieve excellent battery performance and safety at a high level in a battery device.

1: Cross-sectional image of heat resistant particles (inorganic or organic particles)
2: maximum inscribed circle 3: minimum circumscribed circle
4: Roll 5: Fixed end
6: weight 7: central portion
10: porous laminated film 11: polyolefin-based porous film
12: porous layer 12a: heat-resistant particle
12b: Binder

Claims (11)

A polyolefin-based porous film,
A porous layer laminated on at least one main surface of the polyolefin-based porous film, wherein the porous layer has an aspect ratio Ps of not less than 1.5 and not more than 10 and a deformation degree Ps defined by the formula (1) for a cross- A porous layer containing heat-resistant particles of not more than 1.4
Wherein the porous laminated film is a laminated film.
Ps = Rl / Rs ... (One)
Ps: Lee Hyung Soo
Rl: radius of the least circumscribed circle
Rs: radius of maximal inscribed circle The porous laminated film according to claim 1, wherein the heat resistant particles comprise calcium carbonate. The porous laminated film according to claim 1, wherein the ratio of the mass ratio of the binder in the porous layer to the mass ratio of the heat resistant particles in the porous layer is 0.1 to 1. The porous laminated film according to claim 1, wherein the mass ratio of the heat resistant particles in the porous layer is 40 mass% or more and less than 90 mass%. The porous laminated film according to claim 1, wherein the porous layer comprises a modified polyolefin as a binder. The porous laminated film according to claim 1, wherein the polyolefin-based porous film comprises polypropylene. The porous laminated film according to claim 1, wherein the polyolefin-based porous film has a? -Fixing ability. The porous laminated film according to claim 1, wherein the binder is melted and bound between the binder and the heat-resistant particles, and between the binder and the polyolefin-based porous film. The porous laminated film according to claim 1, wherein the binder has a melting point of 70 to 120 ° C. A separator for power storage device, comprising the porous laminated film according to any one of claims 1 to 9. A power storage device provided with a separator provided between a positive electrode and a negative electrode for transmitting ions in an electrolyte solution while preventing contact between them,
Wherein said separator is the separator for power storage device according to claim 10.

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