KR20230155243A - Olefin polymer porous substrate, separator for electrochemical device and electrochemical device comprising the same - Google Patents

Abstract

The present invention is an olefin polymer porous paper characterized by a start-up shear viscosity ^{of 1.5} The present invention relates to a separator for an electrochemical device and an electrochemical device including a support, wherein the olefin polymer porous support has sufficient resistance to external force even in high temperature exposure situations, thereby ensuring the safety of the electrochemical device.

Description

Olefin polymer porous support, separator and electrochemical device containing the same for electrochemical devices {OLEFIN POLYMER POROUS SUBSTRATE, SEPARATOR FOR ELECTROCHEMICAL DEVICE AND ELECTROCHEMICAL DEVICE COMPRISING THE SAME}

The present invention relates to an olefin polymer porous support, a separator for an electrochemical device containing the same, and an electrochemical device.

Additionally, it relates to a method of manufacturing the separator for the electrochemical device.

Recently, interest in energy storage technology has been increasing. Efforts to research and develop electrochemical devices are becoming more concrete as their application areas expand to include mobile phones, camcorders, laptop PCs, and even electric vehicles. Electrochemical devices are the field that is receiving the most attention in this respect, and among them, the development of secondary batteries capable of charging and discharging is the focus of attention.

Among the secondary batteries currently in use, the lithium secondary battery developed in the early 1990s has the advantage of having a higher operating voltage and much higher energy density than conventional batteries such as Ni-MH, Ni-Cd, and lead sulfate batteries that use aqueous electrolyte solutions. is in the spotlight.

These lithium secondary batteries are composed of an anode, a cathode, an electrolyte, and a separator. Among these, the separator has insulation and high porosity to electrically insulate the anode and cathode, and has high ionic conductivity to increase the permeability of lithium ions. is required.

Meanwhile, in order for lithium secondary batteries to be applied to electric vehicles (EV), groundbreaking improvements in safety and unit cost are required.

In the case of the ethylene polymer (PE) separator, a representative olefin polymer separator, the melting point (Tm) is low, but if the battery temperature rises above the melting point of the ethylene polymer in a battery misuse environment, the separator melts within the battery.

When a melt-down phenomenon occurs due to melting, the separator is easily deformed by external shear stress, so the cathode and anode come into direct contact, causing a short circuit and a fire due to heat generation. It continues.

The problem to be solved by the present invention is to provide an olefin polymer porous support that can sufficiently secure resistance to external force even in high temperature exposure situations and a separator for electrochemical devices containing the same.

Another problem that the present invention aims to solve is to provide a method of manufacturing a separator for an electrochemical device that can ensure sufficient resistance to external force even in high temperature exposure situations.

Another problem that the present invention aims to solve is to provide an electrochemical device that can ensure safety by ensuring sufficient resistance to external force even in high temperature exposure situations.

In order to solve the above problem, according to one aspect of the present invention, olefin polymer porous supports of the following embodiments are provided.

The first embodiment is,

Regarding an olefin polymer porous support, characterized in that the start-up shear viscosity measured 300 seconds after applying shear stress at 230°C and a shear rate of 0.01 s ^-1 is ^1.5 will be.

The second embodiment is, in the first embodiment,

The meltdown temperature of the olefin polymer porous support may be 160°C or higher.

The third embodiment is, in the first or second embodiment,

The air permeability of the olefin polymer porous support may be 300 s/100 ml or less.

The fourth embodiment is, in any one of the first to third embodiments,

The olefin polymer porous support may have a porosity of 35% to 50%.

The fifth embodiment is, in any one of the first to fourth embodiments,

The puncture strength of the olefin polymer porous support may be 300 to 600 gf.

The sixth embodiment is, in any one of the first to fifth embodiments,

The olefin polymer porous support may have a shutdown temperature of 145°C or lower.

The seventh embodiment is, in any one of the first to sixth embodiments,

The olefin polymer porous support may be an olefin polymer porous support containing a crosslinked structure.

The eighth embodiment is, in the seventh embodiment,

The olefin polymer porous support may be an olefin polymer porous support containing a cross-linked structure in which cross-linking agents are cross-linked to each other and surround the surface of the polymer chains.

The ninth embodiment is, in the eighth embodiment,

The crosslinking agent is 2-Hydroxyethyl methacrylate (HEMA), 2-hydroxyethyl acrylate (HEA), isobornyl acrylate (IBOA), It may include poly(ethylene glycol) diacrylate (PEGDA), polyether polyurethane acrylate, polyester polyurethane acrylate, or two or more of these. there is.

The tenth embodiment is, in the seventh embodiment,

The olefin polymer porous support may be an olefin polymer porous support containing a cross-linked structure in which polymer chains are directly connected.

The eleventh embodiment is, in any one of the seventh to tenth embodiments,

The starting shear viscosity of the olefin polymer porous support measured 300 seconds after applying shear stress at 230°C and a shear rate of 0.01 s ^-1 is that of the olefin polymer porous support without a crosslinked structure at 230°C and a shear rate of 0.01 s ^-1 . It may be more than 1.5 times the starting shear viscosity measured 300 seconds after applying the shear stress.

The twelfth embodiment is, in any one of the seventh to eleventh embodiments,

The melt down temperature of the olefin polymer porous support may be 20°C or more higher than the melt down temperature of the olefin polymer porous support without a crosslinked structure.

The thirteenth embodiment is, in any one of the seventh to twelfth embodiments,

The porosity of the olefin polymer porous support may be 70% or more compared to the porosity of the olefin polymer porous support without a crosslinked structure.

The fourteenth embodiment is, in any one of the seventh to thirteenth embodiments,

The puncture strength of the olefin polymer porous support may be 80 to 99% of the puncture strength of the olefin polymer porous support without a crosslinked structure.

In order to solve the above problem, according to one aspect of the present invention, separators for electrochemical devices of the following embodiments are provided.

The 15th embodiment is,

It relates to a separator for an electrochemical device comprising an olefin polymer porous support according to any one of the first to fourteenth embodiments.

The sixteenth embodiment is, in the fifteenth embodiment,

The separator for an electrochemical device may be located on at least one side of the olefin polymer porous support and may include an inorganic hybrid pore layer containing an inorganic filler and a binder polymer.

In order to solve the above problem, according to one aspect of the present invention, a method for manufacturing a separator for an electrochemical device of the following embodiments is provided.

The 17th embodiment is,

Preparing an olefin polymer porous support containing a photoinitiator; and

It relates to a method of manufacturing a separator for an electrochemical device, comprising the step of irradiating ultraviolet rays to the olefin polymer porous support.

The 18th embodiment, in the 17th embodiment,

The step of preparing an olefin polymer porous support containing the photoinitiator is,

It may include applying a photocrosslinking composition containing a water-soluble photoinitiator and an aqueous solvent to an olefin polymer porous support.

The 19th embodiment is, in the 17th embodiment,

The step of preparing an olefin polymer porous support containing the photoinitiator is,

It may include applying a photocrosslinking composition containing an emulsion or colloidal photoinitiator and an aqueous dispersion medium to an olefin polymer porous support.

The 20th embodiment, in the 19th embodiment,

The average particle diameter of the photoinitiator in the form of an emulsion or colloid may be 1 nm to 100 ㎛.

The 21st embodiment is the 19th or 20th embodiment,

The photoinitiator in the form of an emulsion or colloid may include a non-aqueous photoinitiator.

The 22nd embodiment is, in any one of the 19th to 21st embodiments,

The photoinitiator in the form of an emulsion or colloid may include a eutectic mixture.

The 23rd embodiment is, in any one of the 17th to 22nd embodiments,

The photoinitiator may include a Type 2 photoinitiator.

The 24th embodiment is, in any one of the 17th to 22nd embodiments,

The photoinitiator may include a Type 1 photoinitiator.

The twenty-fifth embodiment is in any one of the eighteenth to twenty-second embodiments and the twenty-fourth embodiment,

The composition for photocrosslinking may include a Type 1 photoinitiator and a crosslinking agent.

In the twenty-sixth embodiment, in any one of the eighteenth embodiment and the twenty-third to twenty-fifth embodiments,

The water-soluble photoinitiator is 2-carboxymethoxythioxanthone, 3-(3,4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy)-2-hydroxypropyl]trimethyl ammonium Chloride (3-(3,4-dimethly-9-oxo-9H-thioxanthen-2-yloxy)-2-hydroxypropyl]trimethyl ammonium chloride), carboxylated camphorquinone, 2-hydroxy-4` -(2-hydroxy ethoxy)-2-methylpropiophenone (2-hydroxy-4`-(2-hydroxy ethoxy)-2-methylpropiophenone) (Irgacure 2959), or it may include two or more of these. .

The 27th embodiment is, in any one of the 19th to 25th embodiments,

The photoinitiator in the form of an emulsion or colloid is 1-hydroxy-cyclohexyl-phenyl-ketone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide) ( TPO), Irgacure819, Irgacure2959, Omnirad500, Thioxanthone (TX: Thioxanthone), thioxanthone derivative, benzophenone (BPO: Benzophenone), benzophenone derivative, or any of these It may contain 2 or more.

The 28th embodiment is, in any one of the 18th embodiment and the 23rd to 26th embodiments,

The photoinitiator may be included in an amount of 0.05 to 0.5 parts by weight based on 100 parts by weight of the aqueous solvent.

The 29th embodiment is, in any one of the 19th to 25th embodiments and the 27th embodiment,

The photoinitiator may be included in an amount of 0.05 to 0.5 parts by weight based on 100 parts by weight of the aqueous dispersion medium.

The 30th embodiment is, in any one of the 17th to 29th embodiments,

The amount of irradiated ultraviolet rays is 10 to 2000 It may be mJ/cm ² .

In order to solve the above problem, according to one aspect of the present invention, an electrochemical device of the following embodiment is provided.

The 31st embodiment is,

It includes an anode, a cathode, and a separator for an electrochemical device interposed between the anode and the cathode,

It relates to an electrochemical device, wherein the separator for an electrochemical device is a separator for an electrochemical device according to the 15th embodiment.

The olefin polymer porous support according to an embodiment of the present invention has a high starting shear viscosity, making it easy to prevent or delay deformation by external force at high temperatures.

In an electrochemical device including an olefin polymer porous support as a separator according to an embodiment of the present invention, the possibility of heat generation due to short circuit may be reduced or delayed as deformation of the separator due to external force is prevented or delayed at high temperatures.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention along with the contents of the above-described invention. Therefore, the present invention is limited to the matters described in such drawings. It should not be interpreted in a limited way.
Figure 1 shows the starting shear viscosity measured from 0 to 300 seconds after applying shear stress to the olefin polymer porous supports prepared in Examples 1 to 3 and Comparative Example 1 at 230°C and a shear rate of 0.01 s ^-1 . It's a degree.

Hereinafter, preferred embodiments of the present invention will be described in detail. Prior to this, the terms or words used in this specification and claims should not be construed as limited to their usual or dictionary meanings, and the inventor should appropriately use the concept of terms to explain his or her invention in the best way. It must be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle of definability.

Therefore, the configuration described in the examples of this specification is only one of the most preferred embodiments of the present invention and does not represent the entire technical idea of the present invention, so various equivalents and modifications can be substituted for them at the time of filing the present application. It should be understood that there may be examples.

The olefin polymer porous support according to one aspect ^of the present invention has a start-up shear viscosity of ^1.5 Characterized by being .s or higher.

The starting shear viscosity is a parameter that represents the resistance that prevents deformation of the material when shear stress is applied. The higher the starting shear viscosity, the greater the material's resistance to deformation.

Unlike Newtonian fluids, thermoplastic polymer materials with a molecular weight above a certain level exhibit a unique rheological viscoelastic phenomenon at temperatures above the melting temperature. In particular, as the shear rate approaches 0, that is, as the shear rate becomes lower, a yielding phenomenon in which the shear viscosity increases rapidly may occur. In the case of low shear rate, it reflects the phenomenon when external force is slowly applied at high pressure. The higher the starting shear viscosity under the low shear rate condition where external force is gradually applied, the higher the high temperature stability of the olefin polymer porous support can be further strengthened. 0.01 s ^-1 corresponds to sufficiently low shear rate conditions.

That is, the starting shear viscosity value at 230°C and a shear rate of 0.01 s ^-1 represents the characteristics of the olefin polymer porous support at the time of first exposure to high temperature and high pressure conditions. The higher the starting shear viscosity value at 230°C and shear rate of 0.01 s ^-1 , the higher the high temperature stability of the olefin polymer porous support can be further strengthened.

After 300 seconds of applying shear stress, a steady state is reached with no change in viscosity, so it is appropriate to compare viscosity levels.

The olefin polymer porous support according to an embodiment ^of the present invention has a start-up shear viscosity of ^1.5 If it is .s or higher, the olefin polymer porous support may not be easily deformed by external force at high temperatures. In particular, when external force is gradually applied at high pressure, the olefin polymer porous support may not be easily deformed by the external force at high temperature.

In the present invention, the starting shear viscosity can be measured using a rheological property measuring device (ARES-G2, TA Instrument). For example, rheological properties can be measured using a time sweep test method at a temperature range of 230°C and a shear rate of 0.01 s ^-1 using a rheological property measuring device (ARES-G2, TA Instrument).

In one embodiment of the present invention, the start-up shear viscosity measured 300 seconds after applying shear stress to the olefin polymer porous support at 230°C and a shear rate of 0.01 s ^-1 is ^{3.79 Pa.s or} more ^{, or 4.74} It may be less than Pa.s.

In one embodiment of the present invention, the meltdown temperature of the olefin polymer porous support is 160°C or higher, or 163°C or higher, or 170°C or higher, or 171°C or higher, or 178°C or higher, or 180°C or higher, or 190°C or higher. It may be ℃ or higher, or 200℃ or higher, or 210℃ or higher, or 220℃ or higher. Additionally, it may be 230°C or lower. When the olefin polymer porous support has the above-mentioned meltdown temperature, the safety of the separator for electrochemical devices and the electrochemical device containing it can be further improved.

In this specification, meltdown temperature can be measured by thermomechanical analysis (TMA). For example, after collecting samples in the machine direction and the transverse direction, a sample of 4.8 mm in width x 8 mm in length was placed in a TMA instrument (TA Instrument, Q400) and a tension of 0.01 N was applied. While changing the temperature from 30°C to 220°C at a temperature increase rate of 5°C/min, the temperature at which the length suddenly increases and the sample breaks can be measured as the meltdown temperature.

In one embodiment of the present invention, the olefin polymer porous support may have a shutdown temperature of 145°C or less, or 142°C or less, or 140°C or less, or 133°C to 140°C. When the olefin polymer porous support has the above-described shutdown temperature, the separator for an electrochemical device containing the olefin polymer porous support can ensure safety against overcharge and the olefin polymer is used in the high temperature and pressurization process during battery assembly. It may be easier to prevent problems where the pores of the porous support are damaged and the resistance increases.

In this specification, the shutdown temperature is measured by measuring the time (sec) it takes for 100 ml of air to pass through the olefin polymer porous support at a constant pressure of 0.05 Mpa when the temperature is raised at 5°C per minute using Wang Yeon-sik ventilation equipment. It can be measured by measuring the temperature at which the air permeability of the olefin polymer porous support rapidly increases.

In one embodiment of the present invention, the olefin polymer porous support has an air permeability of 300 s/100 ml or less, 200 s/100 ml. It may be less than or equal to 100 s/100 ml, or less than or equal to 91 s/100 ml, or less than or equal to 85 s/100 ml, or less than or equal to 50 s/100 ml. The olefin polymer porous support that satisfies the above-mentioned air permeability may be more suitable for use as a separation membrane.

In this specification, air permeability can be measured by the ASTM D726-94 method. Breathability (Gurley), as used here, is resistance to air flow and is measured by a Gurley densometer. The air permeability value described here is expressed as the time (seconds) it takes for 100 ml of air to pass through the cross section of 1 in ² sample porous support under a pressure of 12.2 inH ₂ O, that is, the ventilation time.

In one embodiment of the present invention, the olefin polymer porous support has a porosity of 20% or more, or 31% or more, or 35% or more, or 40% or more, or 45% or more, or 46% or more, or 50% or more. or more, or more than 60%, or less than 70%, or less than 60%, or less than 50%, or less than 46%, or less than 45%. When the porosity of the olefin polymer porous support satisfies the above-mentioned range, it may be easier for the olefin polymer porous support to satisfy the air permeability of 300 s/100 ml or less.

In this specification, the porosity of the olefin polymer porous support was calculated by the following equation by collecting a specimen of a certain area and measuring its weight.

Porosity (%) = 100 - [(Weight of specimen) / (Area of specimen

In one embodiment of the present invention, the puncture strength of the olefin polymer porous support is 200 gf or more, or 250 gf or more, or 300 gf or more, or 375 gf or more, or 445 gf or more, or 450 gf or more. , or 600 gf or more, or 700 gf or more, or 800 gf or less, or 700 gf or less, or 600 gf or less. When the puncture strength of the olefin polymer porous support satisfies the above-mentioned range, it may be easier to secure sufficient mechanical strength of the olefin polymer porous support.

As used herein, puncture strength may be measured according to ASTM D2582. Specifically, after setting the 1 mm round tip to operate at a speed of 120 mm/min, the puncture strength can be measured according to ASTM D2582.

In one embodiment of the present invention, the olefin polymer porous support may be an olefin polymer porous support containing a crosslinked structure.

In one embodiment of the present invention, the olefin polymer porous support may be an olefin polymer porous support containing a cross-linked structure in which cross-linking agents are cross-linked to each other and surround the surface of the polymer chains.

In the present specification, the olefin polymer porous support containing a cross-linked structure in which the cross-linking agents are cross-linked to each other and covers the surface of the polymer chain covers the polymer chain in a state in which the cross-linking agents are cross-linked to each other on the surface of the polymer chain, and the polymer chains themselves are cross-linked. It refers to an olefin polymer porous support in an unformed state.

In another embodiment of the present invention, the olefin polymer porous support may be an olefin polymer porous support containing a cross-linked structure having a cross-linked structure in which polymer chains are directly connected.

In the present specification, 'crosslinked structure in which polymer chains are directly connected' refers to a polymer chain substantially composed of olefin polymers, more preferably a polymer chain composed only of olefin polymers, which becomes reactive by the addition of a photoinitiator, thereby forming a polymer chain. It means a state in which they are directly cross-linked with each other. Therefore, the crosslinking reaction that occurs between crosslinking agents when an additional crosslinking agent is added does not correspond to the 'crosslinking structure in which polymer chains are directly connected' referred to in the present invention. In addition, the cross-linking reaction that occurs between the additional cross-linking agent and the polymer chain, even if the polymer chain is substantially composed of olefin polymers or only olefin polymers, is in the 'cross-linked structure in which polymer chains are directly connected' referred to in the present invention. Does not apply.

Cross-linking between photoinitiators may occur, or photoinitiators and polymer chains may cross-link with each other. This cross-linking structure has a lower reaction enthalpy than the cross-linking structure between polymer chains in the olefin polymer porous support, so there is a risk of decomposition during battery charging and discharging, causing side reactions. . In one embodiment of the present invention, the olefin polymer porous support may include only a cross-linked structure in which polymer chains are directly connected, and may not include a cross-linked structure in which the photoinitiator and the polymer chains are directly connected.

In one embodiment of the present invention, the olefin polymer porous support includes only a cross-linked structure in which polymer chains are directly connected, and does not include a cross-linked structure in which the photoinitiator and the polymer chains are directly connected.

Unlike Newtonian fluids, non-crosslinked thermoplastic polymer materials with a molecular weight above a certain level exhibit a unique rheological viscoelastic phenomenon at temperatures above the melting temperature. Generally, at low shear rates, there is a region where the shear viscosity is constant, and at higher shear rates, a shear thinning phenomenon may occur where the shear viscosity decreases as the shear rate increases. On the other hand, when the chains of thermoplastic polymers are cross-linked and have a network structure, they become pseudo-solids that exhibit characteristics closer to solids. In particular, when a dense cross-linked network is formed between polymer chains, a yielding phenomenon may occur in which shear viscosity rapidly increases as the shear rate approaches 0. Accordingly, when the olefin polymer porous support has a crosslinked structure, the higher the starting shear viscosity under low shear rate conditions where external force is gradually applied, the higher the high temperature safety can be further strengthened.

In one embodiment of the present invention, when the olefin polymer porous support has a cross-linked structure in which polymer chains are directly connected, the olefin polymer porous support becomes a pseudo-solid, and the shear viscosity becomes steeper as the shear rate converges to 0. A yielding phenomenon that increases rapidly may occur, and accordingly, under low shear rate conditions where external force is gradually applied, it may be easier to have a large starting shear viscosity of the olefin polymer porous support. In other words, the start-up shear viscosity of the olefin polymer porous support measured 300 seconds after applying shear stress at 230°C and a shear rate of 0.01 s ^-1 is more than ^1.5 can do.

Additionally, when the olefin polymer porous support has a crosslinked structure, it may be easier to increase the meltdown temperature. For example, the meltdown temperature of the olefin polymer porous support may be more than 160°C.

In one embodiment of the present invention, the degree of crosslinking of the olefin polymer porous support is 10% or more, or 15% or more, or 20% or more, or 30% or more, or 35% or more, or 40% or more, or 45% or more. , or 55% or more, or 80% or less, or 55% or less, or 45% or less, or 40% or less, or 35% or less. You can. When the crosslinking degree of the olefin polymer porous support satisfies the above-mentioned range, it may be easier to have the above-mentioned starting shear viscosity value.

At this time, the degree of crosslinking is calculated by measuring the remaining weight after immersing the olefin polymer porous support in a xylene solution at 135°C and boiling it for 12 hours according to ASTM D 2765, and calculating it as a percentage of the remaining weight compared to the initial weight.

In one embodiment of the present invention, when the olefin polymer porous support includes a cross-linked structure, the number of double bonds present in the olefin polymer chain when measured by H-NMR is 0.01 to 0.6 per 1000 carbon atoms, or It may be 0.02 to 0.5. When the olefin polymer porous support has the number of double bonds described above, it can be easy to minimize the problem of battery performance deterioration at high temperature and/or high voltage.

In one embodiment of the present invention, the number of double bonds present in the olefin polymer chain excluding the ends of the olefin polymer porous support may be 0.005 to 0.59 per 1000 carbon atoms as measured by H-NMR. If the olefin polymer porous support has the above-mentioned number of double bonds excluding the terminals, it may be easier to minimize the problem of battery performance deterioration at high temperature and/or high voltage. The term “double bond present in the olefin polymer chain excluding the terminal” refers to the double bond present throughout the olefin polymer chain excluding the terminal of the olefin polymer chain. Here, “terminal” refers to the carbon atom positions connected to both ends of the olefin polymer chain.

In one embodiment of the present invention, the thickness of the olefin polymer porous support may be 3 ㎛ to 16 ㎛, or 5 ㎛ to 12 ㎛. When the thickness of the olefin polymer porous support is within the above-mentioned range, when the olefin polymer porous support is used as a separator for an electrochemical device, the problem of the separator being easily damaged during battery use can be prevented, and the energy density is high. It may be easy to secure.

In one embodiment of the present invention, the olefin polymer porous support has a cross-linked structure, and thus, compared to the olefin polymer porous support without a cross-linked structure, 300 seconds after applying shear stress at 230 ° C. and a shear rate of 0.01 s ^-1 The measured starting shear viscosity can increase significantly. For example, the starting shear viscosity of the olefin polymer porous support measured 300 seconds after applying shear stress at 230°C and a shear rate of 0.01 s ^-1 is that of the olefin polymer porous support without a crosslinked structure at 230°C and a shear rate of 0.01 s. It may be 1.5 times or more, 2 times or more, or 4 to 10 times the starting shear viscosity measured 300 seconds after applying the shear stress at ^-1 .

In one embodiment of the present invention, since the olefin polymer porous support has a cross-linked structure, the meltdown temperature can be significantly increased compared to the olefin polymer porous support that does not contain a cross-linked structure. For example, the melt down temperature of the olefin polymer porous support may be 20°C or more, 15°C or more, or 5 to 10°C higher than the melt down temperature of the olefin polymer porous support without a crosslinking structure.

In one embodiment of the present invention, although the olefin polymer porous support has a cross-linked structure, its porosity may not be significantly deteriorated compared to the olefin polymer porous support that does not contain a cross-linked structure. For example, the porosity of the olefin polymer porous support may be 70% or more, or 75% or more, or 80% to 99%, compared to the porosity of the olefin polymer porous support without a crosslinked structure.

In one embodiment of the present invention, although the olefin polymer porous support has a cross-linked structure, the puncture strength may not be significantly deteriorated compared to the olefin polymer porous support that does not contain a cross-linked structure. For example, the puncture strength of the olefin polymer porous support may be 50 to 99%, 60 to 95%, or 80 to 90% of the puncture strength of the olefin polymer porous support without a crosslinked structure.

In one embodiment of the present invention, although the olefin polymer porous support has a cross-linked structure, the shutdown temperature may not increase significantly compared to the olefin polymer porous support that does not contain a cross-linked structure. Accordingly, while the meltdown temperature of the olefin polymer porous support increases, the shutdown temperature does not increase significantly, so that overcharge safety due to the shutdown temperature can be secured and high temperature safety can be greatly increased.

In one embodiment of the present invention, even when the olefin polymer porous support has a crosslinked structure, the pore structure of the olefin polymer porous support can be maintained substantially as it was before crosslinking.

In one embodiment of the present invention, the olefin polymer is ethylene polymer; propylene polymer; Butylene polymer; Pentene polymer; hexene polymer; octene polymer; copolymers of two or more of ethylene, propylene, butene, pentene, 4-methylpentene, hexene, and octene; Or it may include a mixture thereof.

Non-limiting examples of the ethylene polymer include low-density ethylene polymer (LDPE), linear low-density ethylene polymer (LLDPE), and high-density ethylene polymer (HDPE). The ethylene polymer is a high-density ethylene polymer with high crystallinity and a high melting point of the resin. In this case, it may be easier to increase the modulus while maintaining the desired level of heat resistance.

In one embodiment of the present invention, the weight average molecular weight of the olefin polymer may be 200,000 to 1,500,000, or 220,000 to 1,000,000, or 250,000 to 800,000. When the weight average molecular weight of the olefin polymer is within the above-mentioned range, uniformity and film forming processability of the olefin polymer porous support can be ensured, and ultimately, an olefin polymer porous support with excellent strength and heat resistance can be obtained.

The weight average molecular weight may be measured by gel permeation chromatography (GPC, PL GPC220, Agilent Technologies) under the following conditions.

- Column: PL Olexis (Polymer Laboratories)

- Solvent: TCB (Trichlorobenzene)

- Flow rate: 1.0 ml/min

- Sample concentration: 1.0 mg/ml

- Injection volume: 200 ㎕

- Column temperature: 160℃

- Detector: Agilent High Temperature RI detector

- Standard: Polystyrene (corrected with cubic function)

The olefin polymer porous support according to an embodiment of the present invention can be used as a separator for electrochemical devices.

In one embodiment of the present invention, the separator for an electrochemical device is located on at least one side of the olefin polymer porous support and may include an inorganic mixed pore layer including an inorganic filler and a binder polymer. The inorganic hybrid porous layer may be formed on one or both sides of the olefin polymer porous support.

The inorganic hybrid porous layer includes an inorganic filler and a binder polymer that attaches the inorganic fillers to each other (i.e., the binder polymer connects and fixes the inorganic fillers) so that the inorganic fillers can remain bound to each other, and is attached to the binder polymer. This allows the inorganic filler and the cross-linked structure-containing olefin polymer porous support to remain bound. The inorganic hybrid porous layer can improve the safety of the separator by preventing the olefin polymer porous support containing a cross-linked structure from exhibiting extreme heat shrinkage behavior at high temperatures due to the inorganic filler. For example, the thermal contraction rate of the separator in the machine direction and transverse direction measured after leaving at 150°C for 30 minutes is 20% or less, or 2% to 15%, or 2% to 10%, respectively. , or 2% to 5%.

Throughout this specification, 'Machine Direction' refers to the longitudinal direction of the separator in the direction in which the separator is continuously produced, and 'Transverse Direction' refers to the transverse direction of the machine direction, i.e. , refers to the direction perpendicular to the direction in which the separator is continuously produced and the direction in which the separator is long.

In one embodiment of the present invention, the inorganic mixed porous layer is bound to each other by the binder polymer in a state in which the inorganic fillers are filled and in contact with each other, resulting in interstitial volumes between the inorganic fillers. is formed, and the interstitial volume between the inorganic fillers becomes an empty space and may have a structure that forms pores.

The inorganic filler is not particularly limited as long as it is electrochemically stable. That is, the inorganic filler that can be used in the present invention is not particularly limited as long as it does not cause oxidation and/or reduction reactions in the operating voltage range of the applied lithium secondary battery (for example, 0 to 5 V based on Li/Li ⁺ ). In particular, when an inorganic filler with a high dielectric constant is used as an inorganic filler, it can contribute to increasing the degree of dissociation of electrolyte salts, such as lithium salts, in the liquid electrolyte, thereby improving the ionic conductivity of the electrolyte solution.

For the reasons described above, in one embodiment of the present invention, the inorganic filler may include a high dielectric constant inorganic filler having a dielectric constant of 5 or more, preferably 10 or more. Non-limiting examples of inorganic fillers with a dielectric constant of 5 or more include BaTiO ₃ , Pb(Zr,Ti)O ₃ (PZT), Pb _1-x La _x Zr _1-y Ti _y O ₃ (PLZT, 0<x<1 , 0<y<1), Pb(Mg _1/3 Nb _2/3 )O ₃ -PbTiO ₃ (PMN-PT), hafnia (HfO ₂ ), SrTiO ₃ , SnO ₂ , CeO ₂ , MgO, Mg ( OH) ₂ , NiO, CaO, ZnO, ZrO ₂ , SiO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , γ-AlOOH, Al(OH) ₃ , SiC, TiO ₂ or mixtures thereof.

Additionally, in another embodiment of the present invention, the inorganic filler may be used as the inorganic filler having a lithium ion transport ability, that is, an inorganic filler that contains lithium element but has a function of moving lithium ions without storing lithium. Non-limiting examples of inorganic fillers with lithium ion transport ability include lithium phosphate (Li ₃ PO ₄ ), lithium titanium phosphate (Li _x Ti _y (PO ₄ ) ₃ , 0<x<2, 0<y<3), _{Lithium aluminum titanium phosphate ( Li _ _ _ _} (LiAlTiP) _x O _y series glass such as O ₅ (0<x<4, 0<y<13), lithium lanthanum titanate (Li _x La _y TiO ₃ , 0<x<2, 0<y<3) , Lithium germanium thiophosphate (Li _x Ge _y P _z S _{w ,} 0<x _{< 4} , 0<y< ₁ , 0<z<1, 0<w<5 ), lithium nitride (Li _x N _y , 0<x _{<4, 0<y<2) such as Li 3 N, SiS 2 series glass ( Li x Si P 2} S ₅ series glass _{( Li x} P _y S _{z , 0} <x <3, 0<y<3, 0<z<7), or mixtures thereof.

In one embodiment of the present invention, the average particle diameter of the inorganic filler may be 0.01 ㎛ to 1.5 ㎛. When the average particle diameter of the inorganic filler satisfies the above-mentioned range, it can be easy to form an inorganic mixed porous layer with uniform thickness and appropriate porosity, the inorganic filler has good dispersibility, and the desired energy density can be achieved. can be provided.

At this time, the average particle diameter of the inorganic filler means D ₅₀ particle size, and “D ₅₀ particle size” means the particle size at 50% of the cumulative distribution of particle numbers according to particle size. The particle size can be measured using a laser diffraction method. Specifically, after dispersing the powder to be measured in a dispersion medium, it is introduced into a commercially available laser diffraction particle size measuring device (for example, Microtrac S3500), and the difference in diffraction patterns according to particle size is measured when the particles pass through the laser beam, thereby distributing the particle size. Calculate . The D50 particle size can be measured by calculating the particle diameter at a point that is 50% of the cumulative distribution of particle numbers according to particle size in the measuring device.

The binder polymer may have a glass transition temperature (Tg) of -200 to 200°C. When the glass transition temperature of the binder polymer satisfies the above-mentioned range, mechanical properties such as flexibility and elasticity of the finally formed inorganic mixed porous layer can be improved. The binder polymer may have ion conduction capabilities. When the binder polymer has ion conduction ability, battery performance can be further improved. The binder polymer may have a dielectric constant of 1.0 to 100 (measurement frequency = 1 kHz), or 10 to 100. When the dielectric constant of the binder polymer satisfies the above-mentioned range, the degree of salt dissociation in the electrolyte solution can be improved.

In one embodiment of the present invention, the binder polymer is poly(vinylidene fluoride-co-hexafluoropropylene), poly(vinylidene fluoride-chlorotrifluoroethylene) ( poly(vinylidene fluoride-co-chlorotrifluoroethylene)), poly(vinylidene fluoride-co-tetrafluoroethylene)), poly(vinylidene fluoride-trichloroethylene) (poly(vinylidene fluoride-co-trichloroethylene)), acrylic polymer, styrene-butadiene copolymer, poly(acrylic acid), poly(methylmethacrylate), poly(butylacrylate) ( poly(butylacrylate)), poly(acrylonitrile), poly(vinylpyrrolidone), poly(vinyl alcohol), poly(vinyl acetate) (poly(vinylacetate)), ethylene vinyl acetate copolymer (poly(ethylene-co-vinyl acetate)), poly(ethylene oxide), poly(arylate), cellulose Acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyanoethylcellulose ( It may include cyanoethylcellulose, cyanoethylsucrose, pullulan, carboxyl methyl cellulose, or two or more of these.

The acrylic polymer may include an acrylic homopolymer obtained by polymerizing only an acrylic monomer, or may include a copolymer of an acrylic monomer and another monomer. For example, the acrylic polymer includes polyacrylic acid, a polymer of ethylhexyl acrylate and methyl methacrylate, poly(methylmethacrylate), and poly(ethylexyl). acrylate), poly(butylacrylate), polyacrylonitrile (poly(acrylonitrile)), a polymer of butylacrylate and methyl methacrylate, or two or more of these.

In one embodiment of the present invention, the binder polymer may be a binder polymer that is dissolved or dispersed in an aqueous dispersion medium. When the binder polymer is dispersed in an aqueous dispersion medium, the binder polymer may be in the form of particles.

In one embodiment of the present invention, the binder polymer may be a binder polymer with excellent heat resistance. When the binder polymer has excellent heat resistance, the heat resistance characteristics of the inorganic hybrid porous layer can be further improved. For example, the thermal contraction rate of the separator in the machine direction and transverse direction measured after leaving at 150°C for 30 minutes is 20% or less, or 2% to 15%, or 2% to 10%, respectively. Or it may easily be 2% to 5%, or 0% to 5%, or 0% to 2%.

In one embodiment of the present invention, the weight ratio of the inorganic filler and the binder polymer may be 95:5 to 99.9:0.1, or 96:4 to 99.5:0.5, or 97:3 to 99:1. When the weight ratio of the inorganic filler and the binder polymer is within the above-mentioned range, the thermal safety of the separator at high temperatures can be improved because the content of the inorganic filler distributed per unit area of the separator is large. For example, the thermal contraction rate of the separator in the machine direction and transverse direction measured after leaving at 150°C for 30 minutes is 20% or less, or 2% to 15%, or 2% to 10%, respectively. Or it may easily be 2% to 5%, or 0% to 5%, or 0% to 2%. In addition, it can be easy to secure enough empty space between the inorganic fillers while ensuring sufficient adhesion between the inorganic fillers.

In one embodiment of the present invention, the average pore size of the inorganic hybrid pore layer may be 0.001 ㎛ to 10 ㎛. The average pore size of the inorganic mixed pore layer can be measured according to capillary flow porometry. The capillary flow pore size measurement method is a method in which the diameter of the smallest pore in the thickness direction is measured. Therefore, in order to measure the average pore size of only the inorganic mixed pore layer by the capillary flow porosity measurement method, the inorganic mixed pore layer is separated from the olefin polymer porous support and used as a non-woven fabric capable of supporting the separated inorganic mixed pore layer. It should be measured in a wrapped state, and at this time, the pore size of the nonwoven fabric should be much larger than the pore size of the inorganic hybrid pore layer.

In one embodiment of the present invention, the porosity of the inorganic mixed porous layer may be 5% to 95%, or 10% to 95%, or 20% to 90%, or 30% to 80%. The porosity corresponds to a value obtained by subtracting the volume calculated by the weight and density of each component of the inorganic mixed pore layer from the volume calculated by the thickness, width, and length of the inorganic mixed pore layer.

The porosity of the inorganic hybrid pore layer was measured by nitrogen gas adsorption and distribution using a scanning electron microscope (SEM) image, a Mercury porosimeter, or a pore distribution analyzer (Bell Japan Inc, Belsorp-II mini). By law, it can be measured using the BET 6 point method.

In one embodiment of the present invention, the thickness of the inorganic hybrid porous layer may be 1.5 ㎛ to 5.0 ㎛ on one side of the olefin polymer porous support. When the thickness of the inorganic hybrid porous layer satisfies the above-mentioned range, adhesion to the electrode is excellent and the cell strength of the battery can be easily increased.

In one embodiment of the present invention, when the separator for an electrochemical device includes an olefin polymer porous support having the above-described crosslinked structure, the air permeability, basis weight, tensile strength, tensile elongation, and electrical Resistance, etc. may not deteriorate significantly compared to the air permeability, basis weight, tensile strength, tensile elongation, electrical resistance, etc. of the electrochemical device separator before crosslinking, and the rate of change may also be small.

When the separator for an electrochemical device according to an embodiment of the present invention includes an olefin polymer porous support having the above-described cross-linked structure, compared to the separator for an electrochemical device before cross-linking, the change rate in air permeability is 10% or less, It can be 0% to 10%, 0% to 5%, or 0% to 3%.

The rate of change in air permeability can be calculated by the following equation.

Rate of change in air permeability (%) = [(Air permeability of the separator for electrochemical devices after cross-linking) - (Air permeability of the separator for electrochemical devices before cross-linking)]/(Air permeability of the separator for electrochemical devices before cross-linking)

Throughout this specification, the “separator for electrochemical devices after crosslinking” refers to an olefin polymer porous support containing a crosslinked structure; Alternatively, it refers to a separation membrane comprising an olefin polymer porous support containing a cross-linked structure, and an inorganic mixed porous layer containing an inorganic filler and a binder polymer located on at least one side of the cross-linked structure-containing olefin polymer porous support.

When the separator for an electrochemical device according to an embodiment of the present invention includes an olefin polymer porous support having the above-described cross-linked structure, compared to the separator for an electrochemical device before cross-linking, the change rate in basis weight is 5% or less, or It may be 0% to 5%.

The rate of change of basis weight can be calculated by the following equation.

Rate of change in basis weight (%) = [(basis weight of separator for electrochemical devices after cross-linking) - (basis weight of separator for electrochemical devices before cross-linking)]/(basis weight of separator for electrochemical devices before cross-linking)

The basis weight (g/m ² ) is expressed by preparing a sample with a width and length of 1 m each and measuring its weight.

When the separator for an electrochemical device according to an embodiment of the present invention includes an olefin polymer porous support having the above-described cross-linked structure, compared to the separator for an electrochemical device before cross-linking, the tensile strength in the machine direction and the orthogonal direction The rate of change in intensity may be 20% or less, or 0% to 20%, or 0% to 10%, or 0% to 9%, or 0% to 8%, or 0% to 7.53%.

The rate of change in tensile strength can be calculated by the following equation.

Rate of change in tensile strength in the machine direction (%) = [(tensile strength in the machine direction of the electrochemical device separator before crosslinking) - (tensile strength in the machine direction of the electrochemical device separator after crosslinking)]/ (Tensile strength in the machine direction of the electrochemical device separator before crosslinking)

Rate of change in tensile strength in the perpendicular direction (%) = [(tensile strength in the perpendicular direction of the electrochemical device separator before crosslinking) - (tensile strength in the perpendicular direction of the electrochemical device separator after crosslinking)]/ (Tensile strength in the perpendicular direction of the electrochemical device separator before crosslinking)

The tensile strength is obtained when the specimen is pulled in the machine direction and transverse direction at a speed of 50 mm/min using Universal Testing Systems (Instron® 3345) according to ASTM D882. This may mean the strength at the point of fracture.

When the separator for an electrochemical device according to an embodiment of the present invention includes an olefin polymer porous support having the above-described cross-linked structure, compared to the separator for an electrochemical device before cross-linking, the tensile strength in the machine direction and the orthogonal direction The rate of change in elongation may be less than 20%, or between 0% and 20%.

The rate of change of tensile elongation can be calculated by the following equation.

Rate of change in tensile elongation in the machine direction (%) = [(tensile elongation in the machine direction of the electrochemical device separator before crosslinking) - (tensile elongation in the machine direction of the electrochemical device separator after crosslinking)]/ (Tensile elongation in the machine direction of the electrochemical device separator before crosslinking)

Rate of change in tensile elongation in the perpendicular direction (%) = [(Tensile elongation in the perpendicular direction of the electrochemical device separator before crosslinking) - (Tensile elongation in the perpendicular direction of the electrochemical device separator after crosslinking)]/ (Tensile elongation in the perpendicular direction of the electrochemical device separator before crosslinking)

The tensile elongation is calculated according to ASTM D882 when the specimen is pulled in the machine direction and transverse direction at a speed of 50 mm/min using Universal Testing Systems (Instron® 3345). The maximum length stretched until fracture can be measured and calculated using the formula below.

Tensile elongation in machine direction (%) = (machine direction length of specimen just before fracture - machine direction length of specimen before stretching)/(machine direction length of specimen before stretching)

Tensile elongation in the transverse direction (%) = (Length in the transverse direction of the specimen just before fracture - Length in the transverse direction of the specimen before stretching)/(Length in the transverse direction of the specimen before stretching)

When the separator for an electrochemical device according to an embodiment of the present invention includes an olefin polymer porous support having the above-described cross-linked structure, compared to the separator for an electrochemical device before cross-linking, the change rate in electrical resistance is 15% or less. , or 2% to 10% or 2% to 5%.

The rate of change of electrical resistance can be calculated by the following equation.

Rate of change in electrical resistance (%) = [(electrical resistance of the separator for electrochemical devices after cross-linking) - (electrical resistance of the separator for electrochemical devices before cross-linking)]/(electrical resistance of the separator for electrochemical devices before cross-linking) )

Electrical resistance can be obtained by measuring the separator resistance using an impedance measurement method after leaving the coin cell manufactured including the separator sample at room temperature for one day.

A method of manufacturing a separator for an electrochemical device according to an embodiment of the present invention includes preparing an olefin polymer porous support containing a photoinitiator; And irradiating ultraviolet rays to the olefin polymer porous support.

Hereinafter, the method of manufacturing a separator for an electrochemical device according to an embodiment of the present invention will be examined focusing on the main parts.

First, prepare an olefin polymer porous support containing a photoinitiator.

In one embodiment of the present invention, the photoinitiator may include a Type 2 photoinitiator. When the photoinitiator includes a Type 2 photoinitiator, the polymer chains in the olefin polymer porous support can be directly photocrosslinked. For example, when the photoinitiator is introduced to the surface of the olefin polymer porous support, the olefin polymer porous support can be crosslinked when irradiated with ultraviolet rays. Here, the “surface of the olefin polymer porous support” may include not only the surface of the outermost layer of the olefin polymer porous support, but also the surface of pores existing inside the olefin polymer porous support. When the photoinitiator includes a Type 2 photoinitiator, it may be easier to directly photocrosslink the polymer chains in the olefin polymer porous support than when it includes a Type 1 photoinitiator.

Specifically, the Type 2 photoinitiator can crosslink the olefin polymer porous support alone as a photoinitiator without any other components such as a crosslinker or co-initiator or synergist. As hydrogen atoms in the photoinitiator are removed through hydrogen abstraction through light absorption alone, the photoinitiator becomes a reactive compound, and this photoinitiator forms radicals in the polymer chain within the olefin polymer porous support, making the polymer chain reactive and forming the polymer chain. This allows them to be directly connected to each other and photo-crosslinked. For example, hydrogen separation reaction by the photoinitiator is possible in a small amount of double bond structure or branch structure present in the olefin polymer, and hydrogen atoms are removed from the olefin polymer chain through the hydrogen separation reaction only by light absorption, forming radicals.

In another embodiment of the present invention, the photoinitiator may include a Type 1 photoinitiator. When the photoinitiator includes a Type 1 photoinitiator, the polymer chains in the olefin polymer porous support can be directly photocrosslinked.

In another embodiment of the present invention, when the photoinitiator includes a Type 1 photoinitiator, it may further include a crosslinking agent. When the photoinitiator further includes a crosslinking agent along with the Type 1 photoinitiator, the crosslinking agent can wrap the surface of the polymer chain in a crosslinked state. The polymer chain itself may not be crosslinked.

The Type 1 photoinitiator forms radicals in the crosslinking agent, causing a crosslinking reaction between the crosslinking agents, so that the crosslinking agents can be crosslinked to each other. Crosslinking agents crosslinked to each other in this way can cover the surface of the polymer chain. In another embodiment of the present invention, the photoinitiator may include both a Type 2 photoinitiator and a Type 1 photoinitiator.

In one embodiment of the present invention, the step of preparing an olefin polymer porous support containing the photoinitiator includes adding the photoinitiator to an extruder for extruding the olefin polymer composition to prepare the olefin polymer porous support. can do.

In another embodiment of the present invention, the step of preparing an olefin polymer porous support containing the photoinitiator includes applying a photocrosslinking composition containing the photoinitiator and a solvent or dispersion medium for the photoinitiator to the outside of the olefin polymer porous support. It may include coating and drying steps.

In this specification, the “coating and drying step on the outside” refers not only to coating and drying the photocrosslinking composition on the surface of the olefin polymer porous support, but also to coating and drying the photocrosslinking composition on the surface of the olefin polymer porous support. It may also include cases where the photocrosslinking composition is coated and dried on the surface of.

Non-limiting examples of methods for coating the photocrosslinking composition on the olefin polymer porous support include dip coating method, die coating method, roll coating method, and comma coating method. , Microgravure coating method, doctor blade coating method, reverse roll coating method, Mayer Bar coating method, direct roll coating method, etc.

The drying step after coating the photocrosslinking composition on the olefin polymer porous support can be performed using a method known in the art, and can be performed in an oven or heated chamber within a temperature range considering the vapor pressure of the solvent or dispersion medium for the photoinitiator used. It can be used in a batch or continuous manner. The drying is to substantially remove the solvent or dispersion medium present in the photo-crosslinking composition, and is preferably performed as quickly as possible considering productivity, etc., and may be performed for, for example, 1 minute or less or 30 seconds or less.

Thermoplastic polymer materials have both elasticity and viscosity above their melting temperature. However, when a thermoplastic polymer material is crosslinked, its elastic nature may increase compared to its viscous nature.

In one embodiment of the present invention, the content of the photoinitiator may be 0.05 parts by weight or more, or 0.075 parts by weight, or 0.15 parts by weight, or 0.2 parts by weight or more, based on 100 parts by weight of the solvent or dispersion medium for the photoinitiator. Additionally, it may be 0.5 part by weight or less, 0.3 part by weight or less, or 0.2 part by weight or less, or 0.15 part by weight or less, or 0.075 part by weight or less. When the content of the photoinitiator satisfies the above-mentioned range, the olefin polymer porous support can easily have a crosslinked structure and it can be easier to prevent side reactions from occurring.

When the content of the photoinitiator satisfies the above-mentioned range, main chain scission of the olefin polymer occurs, losing elasticity and relatively increasing viscosity, and thus the meltdown temperature of the olefin polymer porous support decreases. It may be easier to prevent the problem.

In addition, it may be easier to prevent the viscosity of the olefin polymer porous support from becoming too high, causing the porosity of the olefin polymer porous support to be less than 70% of the porosity of the olefin polymer porous support without a crosslinking structure. Accordingly, appropriate porosity can be secured, making it easier to satisfy the air permeability of the olefin polymer porous support of 300 s/100 ml or less.

In addition, radicals are formed at a level where an appropriate level of crosslinking can occur, resulting in rapid crosslinking reaction that causes shrinkage of the separator or main chain scission of the olefin polymer, thereby affecting other physical properties of the olefin polymer porous support, For example, it may be easier to prevent sacrificing puncture strength, etc. Accordingly, it may be easier for the puncture strength of the olefin polymer porous support to be 50 to 99% of the puncture strength of the olefin polymer porous support without a crosslinked structure.

Even if the photoinitiator is coated with the above-described content, the olefin polymer porous support can be cross-linked by irradiation of ultraviolet rays at a light amount sufficient to ensure mass production productivity (i.e., a light amount less than conventional ones).

In one embodiment of the present invention, the composition for photocrosslinking may be a photoinitiator solution consisting of the photoinitiator and a solvent or dispersion medium for the photoinitiator.

In another embodiment of the present invention, the composition for photocrosslinking may be a slurry for forming an inorganic hybrid porous layer including an inorganic filler, a binder polymer, the photoinitiator, and a solvent or dispersion medium for the photoinitiator.

When the photo-crosslinking composition is a slurry for forming the inorganic hybrid porous layer, the photo-crosslinking composition is coated on the olefin polymer porous support, and the photoinitiator is introduced to the surface of the olefin polymer porous support, thereby forming the olefin polymer porous support when irradiated with ultraviolet rays. The support can have a crosslinked structure, and at the same time, an inorganic mixed porous layer can be formed on at least one side of the olefin polymer porous support.

When using a slurry for forming an inorganic hybrid porous layer as the photocrosslinking composition, equipment for directly applying the photoinitiator to the olefin polymer porous support, such as coating and drying the photocrosslinking composition directly on the olefin polymer porous support. The olefin polymer porous support can have a cross-linked structure by using an inorganic hybrid porous layer forming process without requiring additional equipment.

In particular, when the photoinitiator includes a Type 2 photoinitiator, the slurry for forming an inorganic hybrid porous layer does not require any other monomers other than the photoinitiator to directly crosslink the polymer chains in the olefin polymer porous support, so the photoinitiator is inorganic. Even if included in the slurry for forming an inorganic hybrid porous layer along with filler and binder polymers, monomers, etc. do not prevent the photoinitiator from reaching the surface of the olefin polymer porous support, so the photoinitiator can be sufficiently introduced to the surface of the olefin polymer porous support. .

In general, the olefin polymer porous support itself and the inorganic filler have a high UV blocking effect, so when UV rays are irradiated after forming an inorganic mixed porous layer containing an inorganic filler, the amount of UV irradiation light reaching the olefin polymer porous support may decrease. In the present invention, the olefin polymer porous support can have a crosslinked structure even when irradiated with ultraviolet rays after the inorganic hybrid porous layer is formed.

In one embodiment of the present invention, when the photocrosslinking composition is a slurry for forming the inorganic hybrid porous layer, the photoinitiator may include 2-isopropyl thioxanthone, thioxanthone, or a mixture thereof. 2-Isopropyl thioxanthone or thioxanthone can be photocrosslinked even at long wavelengths with high transmittance. Accordingly, even if a photoinitiator is included in the slurry for forming an inorganic hybrid porous layer containing an inorganic filler and a binder polymer, the olefin polymer porous support can easily have a crosslinked structure.

For the inorganic filler, please refer to the above description.

The binder polymer may be dissolved in a solvent or dispersion medium for the photoinitiator, or may be dispersed without being dissolved, depending on the type of the binder polymer.

The slurry for forming the inorganic hybrid pore layer can be prepared by dissolving or dispersing the binder polymer in a solvent or dispersion medium for the photoinitiator, then adding and dispersing the inorganic filler. The inorganic fillers may be added in a state in which they are previously crushed to have a predetermined average particle size, or after adding the inorganic fillers to the slurry in which the binder polymer is dissolved or dispersed, the inorganic fillers may be milled to a predetermined size using a ball mill method or the like. It can also be dispersed by crushing while controlling the average particle size. At this time, crushing may be performed for 1 to 20 hours, and the average particle size of the crushed inorganic filler may be as described above. Conventional methods can be used as a crushing method, and a ball mill method can be used.

In one embodiment of the present invention, the slurry for forming the inorganic hybrid porous layer may further include additives such as a dispersant and/or a thickener. In one embodiment of the present invention, the additive is polyvinylpyrrolidone (PVP), hydroxy ethyl cellulose (HEC), hydroxy propyl cellulose, HPC), ethylhydroxy ethyl cellulose (EHEC), methyl cellulose (MC), carboxymethyl cellulose (CMC), hydroxyalkyl methyl cellulose ), cyanoethylene polyvinyl alcohol, or two or more of these.

In one embodiment of the present invention, the solid content of the slurry for forming the inorganic mixed porous layer may be 5% by weight to 60% by weight, or 30% by weight to 50% by weight. When the solid content of the slurry for forming the inorganic mixed pore layer is within the above-mentioned range, it can be easy to ensure coating uniformity and it can be easy to prevent the slurry from flowing and causing non-uniformity or requiring a lot of energy to dry the slurry. You can.

In one embodiment of the present invention, the step of preparing an olefin polymer porous support containing the photoinitiator may include applying a photocrosslinking composition containing a water-soluble photoinitiator and an aqueous solvent to the olefin polymer porous support. there is.

In one embodiment of the present invention, the water-soluble photoinitiator is 2-carboxymethoxythioxanthone, 3-(3,4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy)- 2-hydroxypropyl]trimethyl ammonium chloride (3-(3,4-dimethly-9-oxo-9H-thioxanthen-2-yloxy)-2-hydroxypropyl]trimethyl ammonium chloride, carboxylated camphorquinone , 2-hydroxy-4`-(2-hydroxy ethoxy)-2-methylpropiophenone (2-hydroxy-4`-(2-hydroxy ethoxy)-2-methylpropiophenone) (Irgacure 2959), or these It may include two or more of these.

At this time, a crosslinking agent may be used along with the water-soluble photoinitiator. For example, when the water-soluble photoinitiator is a Type 1 photoinitiator, a crosslinking agent may be used together.

The crosslinking agent may include a reactive diluent, a reactive oligomer, or a mixture thereof. The reactive diluent is, for example, 2-Hydroxyethyl methacrylate (HEMA), 2-hydroxyethyl acrylate (HEA), isobornyl acrylate ( IBOA), etc. The reactive oligomer may include, for example, poly(ethylene glycol) diacrylate (PEGDA), polyether polyurethane acrylate, polyester polyurethane acrylate, etc. You can.

The crosslinking agent is used in an amount of 25 parts by weight or more, or 50 parts by weight, or more, or 100 parts by weight, or 200 parts by weight, or 250 parts by weight, or more than 300 parts by weight, or more than 400 parts by weight, based on 100 parts by weight of the water-soluble photoinitiator. may be included. Additionally, it may be included in 500 parts by weight or less, or 400 parts by weight or less, or 300 parts by weight or less, or 250 parts by weight or less, or 200 parts by weight or less, or 100 parts by weight or less. When the cross-linking agent is included in the above-mentioned range, the olefin polymer porous support can easily have a cross-linking structure and it can be easier to prevent side reactions from occurring.

Additionally, the water-soluble photoinitiator may be used in combination with a surfactant. The surfactant may include a fluorine-based surfactant, an ionic surfactant, an aliphatic alcohol-based surfactant, or a mixture thereof. The fluorine-based surfactant, ionic surfactant, and aliphatic alcohol-based surfactant may be water-soluble surfactants.

Non-limiting examples of the fluorine-based surfactant include FC-4430, FC-4432, FC-4434, Novec 4200, Novec 4300, FL2200, FL2300, FL2500, and FL2700.

The aliphatic alcohol-based surfactant may be a nonionic surfactant. Non-limiting examples of such aliphatic alcohol-based nonionic surfactants include poly(ethylene glycol dodecyl ether), polyoxyethylene (5) nonylphenyl ether, ), poly(ethylene glycol sorbitol hexaoleate), etc.

The ionic surfactant may exist as a cation or an anion on the photocrosslinking composition. Non-limiting examples of the ionic surfactant include carboxylic acid salt (-COO ^- ), sulfonic acid salt (-SO ₃ ^- ), sulfuric acid ester salt (-OSO ₃ ^- ), phosphoric acid ester salt (-PO ₃ ^- ), 4 Quaternary ammonium compounds (-R ₄ N ⁺ ), or compounds containing two or more of these as functional groups can be mentioned.

In one embodiment of the present invention, the content of the surfactant is 0.05 parts by weight or more, or 0.1 parts by weight, or 0.2 parts by weight, or 0.3 parts by weight, or 0.4 parts by weight or more, based on 100 parts by weight of the aqueous solvent. Or it may be 0.5 part by weight or less, or 0.4 part by weight or less, or 0.3 part by weight or less.

In another embodiment of the present invention, the step of preparing an olefin polymer porous support containing the photoinitiator includes applying a photocrosslinking composition containing an emulsion or colloidal photoinitiator and an aqueous dispersion medium to the olefin polymer porous support. May include steps.

The photoinitiator in the form of an emulsion or colloid may be dispersed in the aqueous dispersion medium in an emulsion or colloid state.

In one embodiment of the present invention, the average particle diameter of the photoinitiator in the form of an emulsion or colloid is 1 nm or more, or 20 nm or more, or 50 nm or more, or 100 nm or more, or 200 nm or more, or 300 nm or more, or 500 nm or more. It may be nm or more, or 20 μm or more, or 50 μm or more. Also, it may be 100 μm or less, or 50 μm or less, or 30 μm or less, or 20 μm or less, or 500 nm or less, or 300 nm or less, or 200 nm or less, or 100 nm or less, or 50 nm or less, or 20 nm or less. You can. When the average particle size of the photoinitiator in the form of an emulsion or colloid satisfies the above-mentioned range, it may be easier to prevent the phenomenon in which the photoinitiator in the form of an emulsion or colloid is not evenly coated on the surface of the olefin polymer porous support, and the olefin polymer It may be easier for a porous support to have a cross-linked structure. Additionally, the storage stability of the photoinitiator in the form of an emulsion or colloid can be further improved.

At this time, the average particle size of the photoinitiator in the form of an emulsion or colloid means D ₅₀ particle size, and “D ₅₀ particle size” means the particle size at 50% of the cumulative distribution of the number of particles according to particle size. The particle size can be measured using Microtrack Litesizer 500.

In one embodiment of the present invention, the photoinitiator in the form of an emulsion or colloid may include a non-aqueous photoinitiator.

In one embodiment of the present invention, the photoinitiator in the form of an emulsion or colloid is 1-hydroxy-cyclohexyl-phenyl-ketone, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (Diphenyl (2,4, 6-trimethylbenzoyl)phosphine oxide (TPO), Irgacure 819, Irgacure 2959, Omnirad500, Thioxanthone (TX: Thioxanthone), Thioxanthone derivative, Benzophenone (BPO: Benzophenone) , benzophenone derivatives, or two or more of these.

The thioxanthone derivatives include, for example, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-dodecylthioxanthone, 2,4-diethylthioxanthone, 2,4-dimethylthioxanthone, 1- Methoxycarbonylthioxanthone, 2-ethoxycarbonylthioxanthone, 3-(2-methoxyethoxycarbonyl)-thioxanthone, 4-butoxycarbonyl-thioxanthone, 3-butoxycarbonyl -7-methylthioxanthone, 1-cyano-3-chlorothioxanthone, 1-ethoxycarbonyl-3-chlorothioxanthone, 1-ethoxycarbonyl-3-ethoxythioxanthone, 1- Ethoxy-carbonyl-3-aminothioxanthone, 1-ethoxycarbonyl-3-phenylsulfurylthioxanthone, 3,4-di[2-(2-methoxyethoxy)ethoxycarbonyl]t Oxanthone, 1-ethoxycarbonyl-3-(1-methyl-1-morpholino-ethyl)-thioxanthone, 2-methyl-6-dimethoxymethyl-thioxanthone, 2-methyl-6- (1,1-dimethoxy-benzyl)-thioxanthone, 2-morpholinomethylthioxanthone, 2-methyl-6-morpholinomethyl-thioxanthone, N-allylthioxanthone-3,4 -dicarboximide, N-octylthioxanthone-3,4-dicarboximide, N-(1,1,3,3-tetramethylbutyl)-thioxanthone-3,4-dicarboximide, 1- Phenoxythioxanthone, 6-ethoxycarbonyl-2-methoxythioxanthone, 6-ethoxycarbonyl-2-methylthioxanthone, thioxanthone-2-polyethylene glycol ester, 2-hydroxy-3- It may include (3,4-dimethyl-9-oxo-9H-thioxanthon-2-yloxy)-N,N,N-trimethyl-1-propanaminium chloride, but is not limited thereto.

The benzophenone derivatives include, for example, 4-phenylbenzophenone, 4-methoxybenzophenone, 4,4'-dimethoxy-benzophenone, 4,4'-dimethylbenzophenone, 4,4'-dichlorobenzophenone, 4 ,4'-dimethylaminobenzophenone, 4,4'-diethylaminobenzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, 4-(4-methylthiophenyl)-benzophenone, 3 ,3'-dimethyl-4-methoxy-benzophenone, methyl-2-benzoyl benzoate, 4-(2-hydroxyethylthio)-benzophenone, 4-(4-tolylthio)benzophenone, 4-benzoyl -N,N,N-trimethylbenzenemethanominium chloride, 2-hydroxy-3-(4-benzoylphenoxy)-N,N,N-trimethyl-propanaminium chloride monohydrate, 4-hydroxy benzophenone , 4-(13-acryloyl-1,4,7,10,13-pentaoxatridecyl)-benzophenone, 4-benzoyl-N,N-dimethyl-N-[2-(1-oxo-2 -Prophenyl)oxy]ethyl-benzene methanaminium chloride, etc. may be included, but are not limited thereto.

In another embodiment of the present invention, the photoinitiator in the form of an emulsion or colloid may include a eutectic mixture. The eutectic mixture may have a lower melting point than the melting points of each of the different types of photoinitiators. Accordingly, when the photoinitiator contains a eutectic mixture, it may be easier to manufacture the photoinitiator in the form of an emulsion or colloid.

In one embodiment of the present invention, the eutectic mixture may have a melting point of, for example, 45° C. or lower. When the eutectic mixture has a melting point in the above-described range, it is possible to prepare a photoinitiator in the form of an emulsion or colloid at a low temperature, making it easier to prepare the photoinitiator in the form of an emulsion or colloid.

In one embodiment of the present invention, the eutectic mixture may include a mixture of type 1 photoinitiator and type 2 photoinitiator.

At this time, the type 1 photoinitiator is 1-hydroxy-cyclohexyl-phenyl-ketone, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (Diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide) ( TPO), Irgacure 819, Irgacure 2959, Omnirad500, or two or more of these.

The type 2 photoinitiator may include thioxanthone (TX), a thioxanthone derivative, benzophenone (BPO: Benzophenone), a benzophenone derivative, or two or more of these.

In one embodiment of the present invention, the weight ratio of the type 1 photoinitiator and the type 2 photoinitiator may be 50:50 to 30:70, or 50:50 to 35:65, or 50:50 to 40:60.

In another embodiment of the present invention, the eutectic mixture may include a mixture of a first type 2 photoinitiator and a second type 2 photoinitiator. The first type 2 photoinitiator and the second type 2 photoinitiator are different types of type 2 photoinitiators. When the eutectic mixture contains a mixture of a first type 2 photoinitiator and a second type 2 photoinitiator, crosslinking efficiency is higher than when it contains a type 1 photoinitiator, making crosslinking of the olefin polymer porous support easier.

For example, the first type 2 photoinitiator may include thioxanthone (TX), a thioxanthone derivative, or two or more of them.

The second type 2 photoinitiator may include benzophenone (BPO: Benzophenone), a benzophenone derivative, or two or more thereof.

In one embodiment of the present invention, the weight ratio of the first type 2 photoinitiator and the second type 2 photoinitiator may be 50:50 to 35:65, or 50:50 to 40:60, or 50:50 to 45:55. there is. When the weight ratio of the first type 2 photoinitiator and the second type 2 photoinitiator satisfies the above-mentioned range, it may be easier to produce a eutectic having a melting point of 45°C or lower. Accordingly, it is possible to manufacture a photoinitiator in the form of an emulsion or colloid at a low temperature, making it easier to manufacture the photoinitiator in the form of an emulsion or colloid.

In one embodiment of the present invention, the photoinitiator in the form of an emulsion or colloid can be prepared by mixing a photoinitiator and a surfactant and then sonicating. For the surfactant, refer to the above description.

In one embodiment of the present invention, the content of the surfactant may be 0.05 parts by weight or more, or 0.1 parts by weight, or 0.2 parts by weight, or 0.3 parts by weight, or 0.4 parts by weight or more, based on 100 parts by weight of the aqueous dispersion medium. there is. Additionally, it may be 0.5 parts by weight or less, or 0.4 parts by weight or less, or 0.3 parts by weight or less. When the content of the surfactant satisfies the above-mentioned range, emulsion formation is sufficiently possible and it is easier to prevent aggregation caused by excessive surfactant above the critical micelle concentration. also, It may be easier to manufacture the photoinitiator in a small and uniform emulsion or colloid form, and it may be easier to ensure storage stability of the photoinitiator in the final manufactured emulsion or colloid form.

In one embodiment of the invention, the weight ratio of the photoinitiator to the surfactant is 100:1 to 1:1, or 100:1 to 100:50, or 100:1 to 100:30, or 100:3 to 100:20. It can be. When the weight ratio of the photoinitiator and surfactant satisfies the above-mentioned range, it can be easier to prepare the photoinitiator in the form of a small and uniform emulsion or colloid, and it is easy to ensure the storage stability of the photoinitiator in the form of the final emulsion or colloid. can do.

In another embodiment of the present invention, the photoinitiator in the form of an emulsion or colloid may be prepared by phase inversion. In this specification, the term “phase change” refers to the phenomenon in which the dispersoid and dispersion medium of the emulsion are replaced with each other.

The photoinitiator in the form of an emulsion or colloid is transferred from a water-in-oil emulsion to an oil-in-water emulsion, or by mixing a solvent and a non-solvent for the photoinitiator. However, the method for producing the photoinitiator in the form of an emulsion or colloid by electroplating is not limited to this.

In one embodiment of the present invention, the photoinitiator in the form of an emulsion or colloid is mixed with a photoinitiator and a surfactant; Preparing a water-in-oil emulsion by dropwise adding an aqueous dispersion medium to a mixture of a photoinitiator and a surfactant; and adding the water-in-oil emulsion to an aqueous dispersion medium and stirring to prepare an oil-in-water emulsion. When preparing a photoinitiator in the form of an emulsion or colloid by the above method, it can be easy to produce a small and uniform photoinitiator in the form of an emulsion or colloid. Accordingly, it may be easier for the photoinitiator in the form of an emulsion or colloid to be evenly coated over the entire olefin polymer porous support, and it may be easier for the olefin polymer porous support to have a crosslinked structure. In addition, it can be easy to ensure the storage stability of the photoinitiator in the form of a final emulsion or colloid.

The surfactant may be the same as or different from the surfactant used in the sonication method described above.

Specifically, a water-in-oil emulsion can be prepared by slowly adding an aqueous dispersion medium dropwise to a mixture of a photoinitiator and a surfactant. Next, in the process of adding the water-in-oil emulsion to the aqueous dispersion and stirring it, as the amount of the aqueous dispersion added gradually increases, phase inversion occurs, thereby producing an oil-in-water emulsion.

At this time, the weight ratio of the photoinitiator and surfactant may be 100:1 to 100:50, or 100:1 to 100:30, or 100:3 to 100:20. When the weight ratio of the photoinitiator and surfactant satisfies the above-mentioned range, it can be easier to prepare the photoinitiator in the form of a small and uniform emulsion or colloid, and it is easy to ensure the storage stability of the photoinitiator in the form of the final emulsion or colloid. can do.

In one embodiment of the present invention, the photoinitiator may include the above-described eutectic mixture. When the photoinitiator contains a eutectic mixture, it is more advantageous to prepare the photoinitiator in the form of an emulsion or colloid using a method of transferring from a water-in-oil emulsion to an oil-in-water emulsion. You can.

When producing a photoinitiator in the form of an emulsion or colloid using a method of transferring the phase from a water-in-oil emulsion to an oil-in-water emulsion, production may be easier when the photoinitiator is in a liquid state. Therefore, when the melting point of the photoinitiator is low, it can be easy to prepare the photoinitiator in the form of an emulsion or colloid at low temperature.

In one embodiment of the present invention, when the melting point of the eutectic mixture is 45°C or lower, a method of transferring from a water-in-oil emulsion to an oil-in-water emulsion is used for the same reason as described above. It may be more advantageous to prepare a photoinitiator in the form of an emulsion or colloid.

In particular, when the photoinitiator contains a eutectic mixture of benzophenone and isopropyl thioxanthone, the melting point of the photoinitiator is 45° C. or lower, so that it changes from a water-in-oil emulsion to an oil-in-water emulsion. It may be more advantageous to produce a photoinitiator in the form of an emulsion or colloid using a method of transferring the photoinitiator to an emulsion.

The temperature at which the aqueous dispersion medium is added dropwise may be at the melting point level of the photoinitiator. For example, it may be 45°C or lower. When the temperature at which the aqueous dispersion medium is added dropwise satisfies the above-mentioned range, the photoinitiator in the form of an emulsion or colloid is used by transferring from a water-in-oil emulsion to an oil-in-water emulsion. It may be more advantageous to manufacture.

The content of the aqueous dispersion medium added dropwise is 0.03 parts by weight based on 100 parts by weight of the mixture of the photoinitiator and surfactant. At least 0.05 parts by weight, or at least 0.08 parts by weight, or at least 0.15 parts by weight, or at least 0.20 parts by weight, or at most 0.25 parts by weight, or at most 0.20 parts by weight, or at most 0.15 parts by weight, or at least 0.08 parts by weight. It may be less than or equal to 0.05 parts by weight. If the content of the aqueous dispersion medium at the time of dropwise addition satisfies the above-mentioned range, agglomeration of the dispersion mediums can be prevented, making it easy to ensure the stability of the photoinitiator in the form of a final emulsion or colloid.

In another embodiment of the present invention, the photoinitiator in the form of an emulsion or colloid may be prepared by mixing a solvent and a non-solvent for the photoinitiator.

Specifically, the photoinitiator in the form of an emulsion or colloid may be prepared by dropwise adding an aqueous dispersion medium to a photoinitiator solution containing a non-aqueous photoinitiator and an organic solvent.

First, a photoinitiator solution is prepared by dissolving a non-aqueous photoinitiator in an organic solvent. At this time, the non-aqueous photoinitiator can dissolve 5 to 100 times the amount of photoinitiator required to crosslink the olefin polymer porous support. When the content of the non-aqueous photoinitiator satisfies the above-mentioned range, the non-aqueous photoinitiator can be easily dispersed in a slurry for forming an inorganic mixed pore layer containing an aqueous dispersion medium using a small amount of an organic solvent.

Next, the photoinitiator solution in which the non-aqueous photoinitiator is dissolved in an organic solvent is mixed with the aqueous dispersion medium. At this time, while stirring the photoinitiator solution, the aqueous dispersion medium is slowly added dropwise to the photoinitiator solution.

In one embodiment of the present invention, the weight ratio of the organic solvent and the aqueous dispersion medium may be 1:99 to 50:50, or 3:97 to 30:70, or 5:95 to 25:75. When the weight ratio of the organic solvent and the aqueous dispersion medium satisfies the above-mentioned range, it may be easier to prepare a photoinitiator in the form of an emulsion or colloid by a phase inversion method.

The organic solvent includes cyclic aliphatic hydrocarbons such as cyclopentane and cyclohexane; aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; acetone, ethylmethyl ketone, diisopropyl ketone, cyclohexanone, methylcyclohexane, and ethyl. Ketones such as cyclohexane; Chlorinated aliphatic hydrocarbons such as methylene chloride, chloroform, and carbon tetrachloride; Esters such as ethyl acetate, butyl acetate, γ-butyrolactone, and ε-caprolactone; Acylonitriles such as acetonitrile and propionitrile ; Ethers such as tetrahydrofuran and ethylene glycol diethyl ether: Amides such as N-methylpyrrolidone and N,N-dimethylformamide; Or it may include two or more of these.

The aqueous solvent or dispersion medium is advantageous in that it is environmentally friendly and does not require excessive amounts of heat for drying. Additionally, there is an advantage that no additional explosion-proof facilities are required.

Depending on the type of binder polymer, the aqueous solvent or dispersion medium may serve as a solvent that dissolves the binder polymer, or it may serve as a dispersion medium that disperses the binder polymer without dissolving it.

In one embodiment of the present invention, the aqueous solvent or dispersion medium may include water, methanol, ethanol, ethylene glycol, diethylene glycol, glycerol alcohol, or two or more thereof.

In one embodiment of the present invention, the step of corona discharge treating the olefin polymer porous support before applying the photocrosslinking composition containing a photoinitiator to the olefin polymer porous support may further be included. The corona discharge treatment can be performed by applying high frequency and high voltage output generated by a predetermined driving circuit between a predetermined discharge electrode provided in the corona discharge processor and a treatment roll. When the olefin polymer porous support is treated with corona discharge, the wettability of the photocrosslinking composition containing an aqueous solvent or dispersion medium to the olefin polymer porous support can be improved.

The olefin polymer porous support is prepared by conventional methods known in the art, such as a wet method using a solvent, diluent or pore forming agent, or a dry method using a stretching method to ensure excellent breathability and porosity from the above-described olefin polymer material. It can be manufactured by forming pores through .

In one embodiment of the present invention, the olefin polymer porous support may be a porous film.

In one embodiment of the present invention, the olefin polymer porous support has a number of double bonds present in the olefin polymer chain of 0.01 per 1000 carbon atoms when measured by H-NMR. It may be from 0.5 to 0.5, or from 0.01 to 0.3. When the olefin polymer porous support has the number of double bonds in the above-mentioned range, it is easier for the olefin polymer porous support to have a crosslinked structure and it can be easier to prevent side reactions from occurring due to excessive generation of radicals. For example, it may be easy to allow crosslinking to occur only between polymer chains, without crosslinking between photoinitiators or between photoinitiators and polymer chains.

In addition, it can be easy to prevent the phenomenon of excessive generation of radicals and shrinkage of the separator due to a rapid crosslinking reaction. Accordingly, it can be easy to prevent the air permeability of the olefin polymer porous support from decreasing after crosslinking.

In addition, it can be easily prevented from sacrificing the mechanical strength of the olefin polymer porous support due to excessive main chain scission of the olefin polymer.

Since crosslinking between olefin polymer chains can occur throughout the olefin polymer chain excluding the terminal portion, the number of double bonds present in the olefin polymer chain excluding the terminal portion may affect the crosslinking of the olefin polymer porous support. In one embodiment of the present invention, the olefin polymer porous support has a number of double bonds present in the olefin polymer chain excluding the terminals of 0.005 per 1000 carbon atoms when measured by H-NMR. It may be from 0.49 to 0.49. When the olefin polymer porous support has the number of double bonds in the above-mentioned range, the olefin polymer porous support can be effectively crosslinked and it can be easy to prevent side reactions from occurring due to excessive generation of radicals. For example, it may be easy to allow crosslinking to occur only between polymer chains, without crosslinking between photoinitiators or between photoinitiators and polymer chains.

In one embodiment of the present invention, the number of double bonds present in the olefin polymer chain can be adjusted by adjusting the type of catalyst, purity, addition of linking agent, etc. during synthesis of the olefin polymer.

In one embodiment of the present invention, the olefin polymer porous support has a BET specific surface area of 10 m ² /g or more, or 13 m ² /g or more, or 15 m ² /g or more, or 20 m ² /g or more, or 23 m ² /g or more, or 25 m ² /g or more, or 27 m ² /g or less, or 25 m ² /g or less, or 23 m 2 /g or less, or 20 m ^{2 /} g or less, or 15 It may be m ² /g or less, or 13 m ² /g or less. When the BET specific surface area of the olefin polymer porous support satisfies the above-mentioned range, the surface area of the olefin polymer porous support increases, and the crosslinking efficiency of the olefin polymer porous support can be increased even when a small amount of photoinitiator is used. .

The BET specific surface area of the olefin polymer porous support can be measured by the BET method. Specifically, the BET specific surface area of the olefin polymer porous support can be calculated from the nitrogen gas adsorption amount under liquid nitrogen temperature (77K) using BELSORP-mino II from BEL Japan.

In one embodiment of the present invention, the olefin polymer porous support may further include an antioxidant. Antioxidants can control the cross-linking reaction between polymer chains by controlling the radicals formed in the olefin polymer chains. Antioxidants can oxidize instead of the polymer chain to prevent oxidation of the polymer chain or absorb the generated radicals to control the crosslinking reaction. Accordingly, the shutdown temperature and mechanical strength of the final manufactured separator may be affected.

In one embodiment of the present invention, the content of the antioxidant is 500 ppm or more, or 1000 ppm or more, or 2000 ppm or more, or 5000 ppm or more, or 10000 ppm or more, or 13000 ppm, based on the content of the olefin polymer porous support. , or more, or 15000 ppm or more, or 20000 ppm or less, or 15000 ppm or less, or 13000 ppm or less, or 10000 ppm or less, or 5000 ppm or less, or 2000 ppm or less, or 1000 ppm or less. When the content of the antioxidant satisfies the above-mentioned range, the antioxidant can sufficiently control excessively generated radicals, making it easy to prevent side reactions, but also causing the surface of the olefin polymer porous support to become uneven. It can be easy to prevent.

These antioxidants are largely divided into a radical scavenger, which stabilizes the olefin polymer by reacting with the radicals generated in the olefin polymer, and a peroxide decomposer, which decomposes the peroxide generated by the radical into a stable molecule. can be classified. The radical scavenger stabilizes the radical by releasing hydrogen and becomes a radical itself, but may remain in a stable form through a resonance effect or rearrangement of electrons. The peroxide decomposition agent can exhibit even better effects when used in combination with the radical scavenger.

In one embodiment of the present invention, the antioxidant may include a first antioxidant that is a radical scavenger and a second antioxidant that is a peroxide decomposer. Since the first antioxidant and the second antioxidant have different operating mechanisms, the antioxidant simultaneously includes a first antioxidant that is a radical scavenger and a second antioxidant that is a peroxide decomposition agent, thereby eliminating unnecessary radicals due to the synergistic effect of the antioxidants. Production inhibition may be easier.

The contents of the first antioxidant and the second antioxidant may be the same or different.

In one embodiment of the present invention, the first antioxidant may include a phenol-based antioxidant, an amine-based antioxidant, or a mixture thereof.

The phenolic antioxidants include 2,6-di-t-butyl-4-methylphenol, 4,4'-thiobis (2-t-butyl-5-methylphenol), and 2,2'-thio diethyl. Bis-[3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate], pentaerythritol-tetrakis-[3-(3,5-di-t-butyl-4 -Hydroxyphenyl)-propionate](Pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), 4,4'-thiobis(2-methyl-6-t- butylphenol), 2,2'-thiobis(6-t-butyl-4-methylphenol), octadecyl-[3-(3,5-di-t-butyl-4-hydroxyphenyl)-propio nate], triethylene glycol-bis-[3-(3-t-butyl-4-hydroxy-5-methylphenol)propionate], thiodiethylene bis[3-(3,5-di-t- butyl-4-hydroxyphenyl) propionate], 6,6'-di-t-butyl-2,2'-thiodi-p-cresol, 1,3,5-tris (4-t-butyl- 3-hydroxy-2,6-xylyl)methyl-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, dioctadecyl 3,3'-thiody propionate, or two or more of them.

In one embodiment of the present invention, the content of the first antioxidant is 500 ppm or more, or 1000 ppm or more, or 2000 ppm or more, or 5000 ppm or more, or 10000 ppm or more, based on the content of the olefin polymer porous support. It may be 12000 ppm or less, or 10000 ppm or less, or 5000 ppm or less, or 2000 ppm or less, or 1000 ppm or less. When the content of the first antioxidant satisfies the above-mentioned range, it can be easier to prevent problems in which side reactions occur due to excessive generation of radicals.

In one embodiment of the present invention, the second antioxidant may include a phosphorus-based antioxidant, a sulfur-based antioxidant, or a mixture thereof.

The phosphorus-based antioxidant decomposes peroxide to create alcohol and changes to phosphate. The phosphorus-based antioxidant is 3,9-bis(2,6-di-t-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5 ]Undecane (3,9-Bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane), bis(2, 6-dicumylphenyl) pentaerythritol diphosphate (Bis(2,4-dicumylphenyl) pentaerythritol diphosphate), 2,2'-methylenebis(4,6-di-t-butylphenyl) 2-ethylhexyl phosphite (2 ,2'-Methylenebis(4,6-di-tert-butylphenyl) 2-ethylhexyl phosphite), bis(2,4-di-t-butyl-6-methylphenyl)-ethyl-phosphite (bis(2,4- di-tert-butyl-6-methylphenyl)-ethyl-phosphite), bis(2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis(2,4-di-t-butylphenyl) Pentaerythritol Diphosphite (bis(2,4-di-t-butylphenyl)Pentaerythritol Diphosphite), Bis(2,4-dicumylphenyl)pentaerythritol Diphosphite, Distearyl Pentaerythritol Diphosphite, Tris(2,4- di-t-butylphenyl) phosphite or two or more thereof.

The sulfur-based antioxidant is 3,3'-thiobis-1,1'-didodecyl ester (3,3'-thiobis-1,1'-didodecyl ester), dimethyl 3,3'-thiodipropionate ( Dimethyl 3,3'-Thiodipropionate), Dioctadecyl 3,3'-thiodipropionate, 2,2-bis{[3-(dodecylthio)-1- oxopropoxy]methyl}propane-1,3diyl-bis[3-(dodecylthio)propionate](2,2-Bis{[3-(dodecylthio)-1-oxopropoxy]methyl}propane- 1,3-diyl bis[3-(dodecylthio)propionate]), or two or more of these.

In one embodiment of the present invention, the content of the second antioxidant is 500 ppm or more, or 1000 ppm or more, or 2000 ppm or more, or 5000 ppm or more, or 10000 ppm or more, based on the content of the olefin polymer porous support. It may be 12000 ppm or less, or 10000 ppm or less, or 5000 ppm or less, or 2000 ppm or less, or 1000 ppm or less. When the content of the second antioxidant satisfies the above-mentioned range, it can be easier to prevent problems in which side reactions occur due to excessive generation of radicals.

In one embodiment of the present invention, when the antioxidant simultaneously includes a first antioxidant that is a radical scavenger and a second antioxidant that is a peroxide decomposer, the content of the first antioxidant The content of the second antioxidant may be 500 ppm to 10,000 ppm based on the content of the olefin polymer porous support, and the content of the second antioxidant may be 500 ppm to 10,000 ppm based on the content of the olefin polymer porous support.

Next, the olefin polymer porous support is irradiated with ultraviolet rays. As ultraviolet rays are irradiated, the olefin polymer porous support has a cross-linked structure.

Ultraviolet irradiation uses an ultraviolet cross-linking device, and can be performed by appropriately adjusting the ultraviolet irradiation time and irradiation light amount in consideration of conditions such as the content ratio of the photoinitiator. For example, the ultraviolet irradiation time and irradiation light amount can be set under conditions that ensure that the olefin polymer porous support has a sufficient cross-linked structure to secure the desired heat resistance and that the separator is not damaged by the heat generated from the ultraviolet lamp. there is. In addition, the ultraviolet lamp used in the ultraviolet cross-linking device can be appropriately selected from high-pressure mercury lamps, metal lamps, gallium lamps, etc. depending on the photoinitiator used, and the emission wavelength and capacity of the ultraviolet lamp can be appropriately selected to suit the process. .

The method for manufacturing a separator containing a crosslinked structure for lithium secondary batteries according to an embodiment of the present invention can crosslink an olefin polymer porous support with a significantly lower amount of ultraviolet irradiation light than the amount of light used for general photocrosslinking, thereby producing a crosslinked structure for lithium secondary batteries. The applicability of the mass production process of the containing separation membrane can be increased. For example, the irradiation amount of ultraviolet rays is 10 mJ/cm ² or more, or 50 mJ/cm ² or more, or 150 mJ/cm ² or more, or 200 mJ/cm ^{2 or} more, or 400 mJ/cm ² or more, or 500 mJ. /cm ² or more, or 600 mJ/cm ² or more, or 1000 mJ/cm ² or more, or 2000 mJ/cm ² or less, or 1000 mJ/cm ² or less, or 600 mJ/cm ^{2 or} less, or 500 mJ/cm ² or less, or 400 mJ/cm ² or less, or 200 mJ/cm ² or less, or 150 mJ/cm 2 or less It may be cm ² or less, or 50 mJ/cm ² or less.

In one embodiment of the present invention, the amount of irradiated ultraviolet light can be measured using Miltec's H type UV bulb and a portable photometer called UV power puck. When measuring the amount of light using Miltec's H type UV bulb, three types of wavelength values are obtained for each wavelength: UVA, UVB, and UVC. The ultraviolet ray of the present invention corresponds to UVA.

In the present invention, the method of measuring the amount of irradiated ultraviolet light is to pass a UV power puck on a conveyor under a light source under the same conditions as the sample, and at this time, the value of the amount of ultraviolet light displayed on the UV power puck is referred to as the 'quantity of irradiated ultraviolet light'.

An electrochemical device can be manufactured by interposing the above separator for an electrochemical device between an anode and a cathode.

The electrochemical device may have various shapes, such as cylindrical, prismatic, or pouch-shaped.

The electrochemical device may include a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery.

The electrode to be applied with the separator for an electrochemical device of the present invention is not particularly limited, and an electrode active material layer containing an electrode active material, a conductive material, and a binder is bound to a current collector according to a common method known in the art. It can be manufactured with

Non-limiting examples of the positive electrode active material among the electrode active materials include layered compounds such as lithium cobalt composite oxide (LiCoO ₂ ) and lithium nickel oxide (LiNiO ₂ ) or compounds substituted with one or more transition metals; Lithium manganese oxide with the formula Li _1+x Mn _2-x O ₄ (where x = 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ , LiMnO _{2 ,} etc.; lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₅ , LiV ₃ O ₄ , V ₂ O ₅ , and Cu ₂ V ₂ O ₇ ; Ni site-type lithium nickel oxide represented by the formula LiNi _1-x M _x O ₂ (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3); _{Chemical formula LiMn 2 -x M} , Cu or Zn); lithium manganese complex oxide; Chemical formula LiMn ₂ O ₄ in which part of Li is substituted with alkaline earth metal ions; disulfide compounds; Fe ₂ (MoO ₄ ) ₃ etc. may be mentioned, but it is not limited to these alone.

Non-limiting examples of negative electrode active materials include common negative electrode active materials that can be used in the negative electrode of conventional electrochemical devices, especially lithium metal or lithium alloy, carbon, petroleum coke, activated carbon, Lithium adsorption materials such as graphite or other carbons may be used.

Non-limiting examples of the positive current collector include foil made of aluminum, nickel, or a combination thereof, and non-limiting examples of the negative current collector include foil made of copper, gold, nickel, or a copper alloy, or a combination thereof. There are foils etc. that are manufactured.

In one embodiment of the present invention, the conductive material used in the negative electrode and the positive electrode may be typically added in an amount of 1% to 30% by weight based on the total weight of each active material layer. These conductive materials are not particularly limited as long as they have conductivity without causing chemical changes in the battery, and examples include graphite such as natural graphite or artificial graphite; Carbon black such as acetylene black, Ketjen black, channel black, furnace black, lamp black, and server black; Conductive fibers such as carbon fiber and metal fiber; fluorinated carbon; Metal powders such as aluminum and nickel powder; Conductive whiskeys such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives may be used.

In one embodiment of the present invention, the binder used in the negative electrode and the positive electrode is a component that assists the bonding of the active material and the conductive material and the bonding to the current collector, and is typically 1% by weight to 1% by weight based on the total weight of each active material layer. It can be added at 30% by weight. Examples of such binders include polyvinylidene fluoride (PVdF), polyacrylic acid (PAA), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, and tetrafluoride. Roethylene, polyethylene, polypropylene, ethylene-propylene-dienter polymer (EPDM), sulfonated EPDM, styrene butadiene rubber, fluorine rubber, various copolymers, etc.

In one embodiment of the present invention, the electrochemical device includes an electrolyte solution, and the electrolyte solution may include an organic solvent and a lithium salt. Additionally, an organic solid electrolyte, an inorganic solid electrolyte, etc. may be used as the electrolyte solution.

Examples of the organic solvent include N-methyl-2-pyrrolidone, ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma-butyrolactone, and 1,2-dimethoxy ethane. , tetrahydroxy franc, 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid. Triesters, trimethoxy methane, dioxolane derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-ividazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ether, methyl pyropionate, ethyl propionate. Aprotic organic solvents such as can be used.

The lithium salt is a material that is easily soluble in the organic solvent, for example, LiCl, LiBr, LiI, LiClO ₄ , LiBF ₄ , LiB ₁₀ Cl ₁₀ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ , LiSbF ₆ , LiAlCl ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, (CF ₃ SO ₂ ) ₂ NLi, lithium chloroborane, lithium lower aliphatic carboxylate, lithium 4-phenyl borate, imide, etc. can be used. there is.

In addition, for the purpose of improving charge/discharge characteristics, flame retardancy, etc. in the electrolyte solution, for example, pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylene diamine, n-glyme, hexaphosphoric acid triamide, Nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinone, N,N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxy ethanol, aluminum trichloride, etc. may be added. there is. In some cases, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further included to provide incombustibility, and carbon dioxide gas may be further included to improve high-temperature storage characteristics.

The organic solid electrolyte includes, for example, polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphoric acid ester polymers, polyagitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, Polymers containing ionic dissociation groups, etc. may be used.

Examples of the inorganic solid electrolyte include Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N-LiI-LiOH, LiSiO ₄ , LiSiO ₄ -LiI-LiOH, Li ₂ SiS ₃ , Li ₄ SiO ₄ , Nitride, halide, sulfate, etc. of Li such as Li ₄ SiO ₄ -LiI-LiOH, Li ₃ PO ₄ -Li ₂ S-SiS ₂ may be used.

The electrolyte injection may be performed at an appropriate stage during the battery manufacturing process, depending on the manufacturing process and required physical properties of the final product. That is, it can be applied before battery assembly or at the final stage of battery assembly.

In one embodiment of the present invention, the process of applying the separator for an electrochemical device to a battery can include lamination (stack) and folding processes of the separator and the electrode in addition to the general winding process.

In one embodiment of the present invention, the separator for an electrochemical device may be interposed between the anode and the cathode of the electrochemical device, and may be disposed between adjacent cells or electrodes when forming an electrode assembly by assembling a plurality of cells or electrodes. may be involved. The electrode assembly may have various structures such as simple stack type, jelly-roll type, stack-folding type, and lamination-stack type.

Hereinafter, the present invention will be described in detail through examples to aid understanding. However, the embodiments according to the present invention may be modified into various other forms, and the scope of the present invention should not be construed as being limited to the following embodiments. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

Example 1

500 g of a composition containing 0.3 parts by weight of Irgacure 2959 based on 100 parts by weight of water, 0.6 parts by weight of 2-hydroxyethyl methacrylate compared to 100 parts by weight of water, and 0.3 parts by weight of surfactant FC4430 compared to 100 parts by weight of water. was dispersed for 20 minutes using a paint shaker (Red Devil Equipment Co.) to prepare an emulsion with an average particle diameter (D50) of 20 ㎛.

An ethylene polymer porous film (Shenzhen Senior Technology Material CO., Gurley air permeability: 84 s/100 mL, porosity: 48%) with a thickness of 11 ㎛ was prepared as an olefin polymer porous support.

The prepared emulsion was immersed in the olefin polymer porous support for 30 seconds, coated and dried, and then irradiated with ultraviolet rays using Miltec's HPI arc lamp (LabCure® Mini) so that the accumulated light amount was 600 mJ/cm ² .

Example 2

An olefin polymer porous support was prepared in the same manner as in Example 1, except that 0.2 parts by weight of Omnirad 500 was added based on 100 parts by weight of water, and ultraviolet rays were irradiated to an integrated light amount of 400 mJ/cm ² .

Example 3

An olefin polymer porous support was prepared in the same manner as in Example 1, except that Omnirad 500 was added in an amount of 5 parts by weight compared to 100 parts by weight of water, and ultraviolet rays were irradiated so that the accumulated light amount was 1200 mJ/cm ² .

Comparative Example 1

As an olefin polymer porous support, an ethylene polymer porous film with a thickness of 11 ㎛ (Shenzhen Senior Technology Material CO., Gurley air permeability: 84 s/100 mL, porosity: 48%) was used as is without any treatment.

Evaluation example: Evaluation of physical properties of olefin polymer porous support

Starting shear viscosity, thickness, air permeability, porosity, puncture strength, and melt of the olefin polymer porous supports prepared in Examples 1 to 3 measured 300 seconds after applying shear stress at 230°C and a shear rate of 0.01 s ^-1 The down temperature was measured and shown in Table 1 below.

In addition, the starting shear viscosity measured from 0 to 300 seconds after applying shear stress to the olefin polymer porous supports prepared in Examples 1 to 3 at 30°C and a shear rate of 0.01 s ^-1 is shown in Figure 1.

As can be seen in Table 1 and Figure 1, it can be confirmed that the olefin polymer porous support prepared in Examples 1 to 3 can be prevented from being deformed by external force at high temperatures compared to the olefin polymer porous support of Comparative Example 1. there was.

In particular, the olefin polymer porous support prepared in Examples 1 and 2 satisfies a level similar to that of the olefin polymer porous support of Comparative Example 1 in terms of thickness, air permeability, porosity, and puncture strength, etc. Compared to the material, it was confirmed that deformation due to external force could be prevented at high temperatures.

Claims (31)

An olefin polymer porous support characterized by a start-up shear ^viscosity of ^1.5 According to paragraph 1,
An olefin polymer porous support, characterized in that the melt down temperature of the olefin polymer porous support is 160°C or higher. According to paragraph 1,
An olefin polymer porous support, characterized in that the olefin polymer porous support has an air permeability of 300 s/100 ml or less. According to paragraph 1,
The olefin polymer porous support is an olefin polymer porous support, characterized in that the porosity is 35% to 50%. According to paragraph 1,
An olefin polymer porous support, characterized in that the olefin polymer porous support has a puncture strength of 300 to 600 gf. According to paragraph 1,
The olefin polymer porous support is characterized in that the shutdown temperature is 145°C or lower. According to paragraph 1,
The olefin polymer porous support is an olefin polymer porous support, characterized in that it is an olefin polymer porous support containing a crosslinked structure. In clause 7,
The olefin polymer porous support is an olefin polymer porous support containing a cross-linked structure in which cross-linking agents are cross-linked to each other and surround the surface of the polymer chains. According to clause 8,
The crosslinking agent is 2-Hydroxyethyl methacrylate (HEMA), 2-hydroxyethyl acrylate (HEA), isobornyl acrylate (IBOA), poly(ethylene glycol) diacrylate (PEGDA), polyether polyurethane acrylate, polyester polyurethane acrylate, or two or more of these. Characterized by olefin polymer porous support. In clause 7,
The olefin polymer porous support is an olefin polymer porous support containing a cross-linked structure having a cross-linked structure in which polymer chains are directly connected. In clause 7,
The starting shear viscosity of the olefin polymer porous support measured 300 seconds after applying shear stress at 230°C and a shear rate of 0.01 s ^-1 is that of the olefin polymer porous support without a crosslinked structure at 230°C and a shear rate of 0.01 s ^-1 . An olefin polymer porous support characterized in that it is more than 1.5 times the starting shear viscosity measured 300 seconds after applying shear stress. In clause 7,
An olefin polymer porous support, characterized in that the melt down temperature of the olefin polymer porous support is at least 20°C higher than the melt down temperature of the olefin polymer porous support without a crosslinking structure. In clause 7,
An olefin polymer porous support, characterized in that the porosity of the olefin polymer porous support is 70% or more compared to the porosity of the olefin polymer porous support without a crosslinked structure. In clause 7,
An olefin polymer porous support, characterized in that the puncture strength of the olefin polymer porous support is 80 to 99% of the puncture strength of the olefin polymer porous support without a crosslinked structure. A separator for an electrochemical device comprising the olefin polymer porous support according to any one of claims 1 to 14. According to clause 15,
A separator for an electrochemical device, characterized in that the separator for an electrochemical device is located on at least one side of the olefin polymer porous support and includes an inorganic mixed porous layer containing an inorganic filler and a binder polymer. Preparing an olefin polymer porous support containing a photoinitiator; and
A method of manufacturing a separator for an electrochemical device, comprising the step of irradiating ultraviolet rays to the olefin polymer porous support. According to clause 17,
The step of preparing an olefin polymer porous support containing the photoinitiator is,
A method of manufacturing a separator for an electrochemical device, comprising the step of applying a photocrosslinking composition containing a water-soluble photoinitiator and an aqueous solvent to an olefin polymer porous support. According to clause 17,
The step of preparing an olefin polymer porous support containing the photoinitiator is,
A method for producing a separator for an electrochemical device, comprising the step of applying a photocrosslinking composition containing an emulsion or colloidal photoinitiator and an aqueous dispersion medium to an olefin polymer porous support. According to clause 19,
A method of manufacturing a separator for an electrochemical device, characterized in that the average particle diameter of the photoinitiator in the form of an emulsion or colloid is 1 nm to 100 ㎛. According to clause 19,
A method of producing a separator for an electrochemical device, characterized in that the photoinitiator in the form of an emulsion or colloid includes a non-aqueous photoinitiator. According to clause 19,
A method of manufacturing a separator for an electrochemical device, characterized in that the photoinitiator in the form of an emulsion or colloid includes a eutectic mixture. According to clause 17,
A method of manufacturing a separator for an electrochemical device, wherein the photoinitiator includes a Type 2 photoinitiator. According to clause 17,
A method of manufacturing a separator for an electrochemical device, wherein the photoinitiator includes a Type 1 photoinitiator. According to claim 18 or 19,
A method of manufacturing a separator for an electrochemical device, wherein the photocrosslinking composition includes a Type 1 photoinitiator and a crosslinking agent. According to clause 18,
The water-soluble photoinitiator is 2-carboxymethoxythioxanthone, 3-(3,4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy)-2-hydroxypropyl]trimethyl ammonium Chloride (3-(3,4-dimethly-9-oxo-9H-thioxanthen-2-yloxy)-2-hydroxypropyl]trimethyl ammonium chloride), carboxylated camphorquinone, 2-hydroxy-4` -(2-hydroxy ethoxy)-2-methylpropiophenone (2-hydroxy-4`-(2-hydroxy ethoxy)-2-methylpropiophenone) (Irgacure 2959), or containing two or more of them. A method of manufacturing a separator for an electrochemical device. According to clause 19,
The photoinitiator in the form of an emulsion or colloid is 1-hydroxy-cyclohexyl-phenyl-ketone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide) ( TPO), Irgacure819, Irgacure2959, Omnirad500, Thioxanthone (TX: Thioxanthone), thioxanthone derivative, benzophenone (BPO: Benzophenone), benzophenone derivative, or any of these A method of manufacturing a separator for an electrochemical device, characterized in that it comprises 2 or more. According to clause 18,
A method of producing a separator containing a crosslinked structure for a lithium secondary battery, characterized in that the photoinitiator is included in an amount of 0.05 to 0.5 parts by weight based on 100 parts by weight of the aqueous solvent. According to clause 19,
A method of producing a separator containing a crosslinked structure for a lithium secondary battery, characterized in that the photoinitiator is included in an amount of 0.05 to 0.5 parts by weight based on 100 parts by weight of the aqueous dispersion medium. According to clause 17,
The amount of irradiated ultraviolet rays is 10 to 2000 A method of manufacturing a separator containing a cross-linked structure for a lithium secondary battery, characterized in that mJ/cm ² . It includes an anode, a cathode, and a separator for an electrochemical device interposed between the anode and the cathode,
An electrochemical device, characterized in that the separator for an electrochemical device is the separator for an electrochemical device according to claim 15.