WO2016059739A1 - 鉛蓄電池用セパレータおよび鉛蓄電池 - Google Patents
鉛蓄電池用セパレータおよび鉛蓄電池 Download PDFInfo
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- WO2016059739A1 WO2016059739A1 PCT/JP2015/003651 JP2015003651W WO2016059739A1 WO 2016059739 A1 WO2016059739 A1 WO 2016059739A1 JP 2015003651 W JP2015003651 W JP 2015003651W WO 2016059739 A1 WO2016059739 A1 WO 2016059739A1
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- microporous film
- glass flakes
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/06—Lead-acid accumulators
- H01M10/12—Construction or manufacture
- H01M10/125—Cells or batteries with wound or folded electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/06—Lead-acid accumulators
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/06—Lead-acid accumulators
- H01M10/08—Selection of materials as electrolytes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/06—Lead-acid accumulators
- H01M10/08—Selection of materials as electrolytes
- H01M10/10—Immobilising of electrolyte
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/14—Electrodes for lead-acid accumulators
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/627—Expanders for lead-acid accumulators
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/68—Selection of materials for use in lead-acid accumulators
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
- H01M4/70—Carriers or collectors characterised by shape or form
- H01M4/72—Grids
- H01M4/73—Grids for lead-acid accumulators, e.g. frame plates
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/50—Current conducting connections for cells or batteries
- H01M50/531—Electrode connections inside a battery casing
- H01M50/54—Connection of several leads or tabs of plate-like electrode stacks, e.g. electrode pole straps or bridges
- H01M50/541—Connection of several leads or tabs of plate-like electrode stacks, e.g. electrode pole straps or bridges for lead-acid accumulators
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Definitions
- the present invention is a microporous film comprising a polyolefin resin (mainly polyethylene), an inorganic powder (mainly silica powder), a plasticizer (mainly mineral oil), and various additives (such as a surfactant).
- a polyolefin resin mainly polyethylene
- an inorganic powder mainly silica powder
- a plasticizer mainly mineral oil
- various additives such as a surfactant.
- the present invention relates to a lead storage battery separator and a lead storage battery using the separator.
- a separator for lead-acid batteries especially for liquid-type lead-acid batteries
- a polyethylene separator is usually 20 to 60% by weight of a polyolefin resin (usually ultra-high molecular weight polyethylene) having a weight average molecular weight of 500,000 or more and a specific surface area.
- inorganic powder usually silica fine powder
- plasticizer usually mineral oil
- surfactant solid content
- separator made of a microporous film comprising 10% by weight and 0 to 5% by weight of additives (antioxidants, weathering agents, etc.).
- the separator made of the microporous film is usually a raw material composition obtained by mixing the polyolefin resin, the inorganic powder, the plasticizer (mixed more than the separator composition), the surfactant, and the additive.
- the base thickness is about 0.1 to 0.3 mm obtained by extruding into a sheet while heating and melting and kneading, roll rolling to a predetermined thickness, and extracting and removing all or part of the plasticizer.
- the sheet has an average pore diameter (mercury intrusion method) of about 0.01 to 0.5 ⁇ m and a porosity (mercury intrusion method) of about 50 to 90% by volume.
- a separator for a liquid lead-acid battery including a ribbed microporous film in which a main plate abutment rib is provided on one side of a flat sheet, the ribbed microporous film is a rib portion and a base.
- the porosity, average pore diameter, and maximum pore diameter of the rib part are reduced to 0.8 times or less than the base part, or the surface opening ratio is reduced to 0.8 or less. It has been proposed that the dendrite does not easily penetrate the plate-contacting main rib, and as a result, the occurrence of a dendrite short in the ribbed microporous film separator can be suppressed.
- Patent Document 1 is an idea that focuses on suppressing the penetration of dendrites in the rib portion, and only the hole structure of the rib portion corresponding to only a part of the entire separator (total area), The dendrite needs to be densified or reduced so that it does not easily penetrate, and the manufacturing process becomes complicated or the manufacturing difficulty level is likely to increase.
- the present invention not a special idea (a difficult countermeasure technique) of densifying or reducing only the hole structure of the rib part in order to suppress the dendrite penetration of the rib part, but the entire separator (total area).
- the purpose is to suppress the penetration of dendrites in the base part, which occupies the majority.
- the present invention is provided for the above purpose.
- the pore structure (pore pathway) obtained by melting and forming a film from a material mainly composed of polyolefin resin, silica powder, and plasticizer
- the pore structure (pore pathway) Do not block the structure (hole path) as much as possible (so as not to hinder the flow of electrolyte ions that deteriorate the electrical resistance), but make it as complex (maze, detour) as possible. I want to extend the growth path.
- a three-dimensional network structure which is a pore structure (hole path) obtained by melt-forming from a material mainly composed of ordinary polyolefin resin, silica powder and plasticizer and removing the plasticizer
- an obstacle that can be a physical obstacle in the path in the thickness direction can be uniformly arranged in the microporous film.
- obstacles are placed in the normal pore structure (pore path) of the microporous film, the way of obstacle placement and obstacles are placed so as not to deteriorate the electrical resistance of the microporous film as much as possible. I want to devise as much as possible.
- the lead-acid battery separator of the present invention is a part of the plasticizer after film formation by melt-kneading a raw material composition mainly comprising a polyolefin-based resin, silica powder, and a plasticizer as described in claim 1.
- the base thickness is 0.1 to 0.3 mm
- the average pore diameter (mercury intrusion method) is 0.01 to 0.5 ⁇ m
- the maximum pore diameter (mercury intrusion method) is 0.3 to 1
- the raw material composition further includes an average particle size of 20 to 800 ⁇ m and an average thickness 0.2 to 8 ⁇ m of glass flakes having no self-forming property, 2 to 15% by weight of the total content of the silica powder and the glass flakes, and 0 to 3% of the silane coupling agent (solid content)
- the microporous film contains The total content of the polyolefin resin, the silica powder, the plasticizer and the glass flake is 90% by weight or more, the content of the polyolefin resin is 20 to 60% by weight, and the content of the silica powder is 40 to 40%
- the plasticizer content is 0-30% by weight
- the glass flake content is 2-15% by weight of the total content of the silica powder and the glass flakes
- the microporous film The glass flakes therein have an average thickness of 0.2 to 8 ⁇ m, and the glass flakes having a particle size of 10 ⁇ m or more in the microporous film have an average particle size of 20 ⁇ m or more.
- the glass flakes are arranged so as to be substantially oriented in the surface direction of the microporous film, and (the content (% by weight) of the glass flakes in the microporous film) / (in the microporous film
- the glass flakes have an average thickness ( ⁇ m) of 1 or more.
- the lead-acid battery separator according to claim 2 is the lead-acid battery separator according to claim 1, wherein (the content (% by weight) of the glass flakes in the microporous film) / (the microporous film).
- the value of the average thickness ( ⁇ m) of the glass flakes in the quality film is 2 or more.
- the lead-acid battery separator according to claim 3 is the lead-acid battery separator according to claim 1 or 2, wherein 80% or more of particles having a particle diameter of 10 ⁇ m or more in the glass flakes in the microporous film.
- the surface direction is arranged so as to be oriented at 20 ° or less with respect to the surface direction of the microporous film.
- the separator for lead acid batteries of Claim 4 is a separator for lead acid batteries of any one of Claims 1 thru
- the lead-acid battery separator according to claim 5 is the lead-acid battery separator according to any one of claims 1 to 4, wherein the glass flakes in the raw material composition and in the microporous film.
- the average thickness is 2 ⁇ m or less
- the content of the glass flakes in the raw material composition is 2 to 8% by weight of the total content of the silica powder and the glass flakes
- the content of the glass flake is 2 to 8% by weight of the total content of the silica powder and the glass flake
- the value of the average thickness ( ⁇ m) of the glass flakes in the microporous film is 10 or less.
- the lead storage battery of the present invention is characterized in that, as described in claim 6, the separator according to any one of claims 1 to 5 is used.
- the present invention not a special idea (a difficult countermeasure method) of densifying or reducing only the hole structure of the rib portion in order to suppress the penetration of dendrites in the rib portion, but in the entire separator (total area).
- a simpler and more efficient method while suppressing the penetration of dendrites in the entire microporous film centering on the base portion occupying the majority.
- the microporous film constituting the lead-acid battery separator of the present invention is basically one of plasticizers after film formation by melting and kneading a raw material composition mainly composed of a polyolefin resin, silica powder, and a plasticizer.
- the base thickness is 0.1 to 0.3 mm
- the average pore diameter (mercury intrusion method) is 0.01 to 0.5 ⁇ m
- the maximum pore diameter (mercury intrusion method) is 0.3 to 0.3 mm.
- Base thickness is a term used to distinguish from the total thickness including rib-like projections when the microporous film has rib-like projections, for example, excluding the height of rib-like projections (rib-like projections). This is the thickness of the film.
- the electrode plate A portion including the main rib for contact is referred to as a rib portion, and a portion not including the main rib for electrode plate contact is referred to as a base portion.
- the raw material composition means a composition composed of all raw materials brought into the melt-kneading process, and means “all raw materials (compositions)”, and specifically, a raw material mixture. It does not mean that it is a melt-kneaded product.
- glass flakes having an average particle diameter of 20 to 800 ⁇ m and an average thickness of 0.2 to 8 ⁇ m and having no self-film forming property are further added to 2 to 15 of the total content of silica powder and glass flakes. It is necessary to contain 0 to 3% by weight of a silane coupling agent (solid content).
- the particle size of the glass flake is defined as the square root of the area when the primary particle of the glass flake is viewed in plan.
- Self-film forming property means that only glass flakes are used alone and dispersed in water to form a dispersion having an appropriate concentration, and this is applied to an appropriate base material having smoothness (eg, a flat metal plate that is difficult to penetrate the dispersion). Etc.) The property of forming a film by itself when applied to the surface to a suitable thickness and dried and solidified.
- the microporous film has a total content of polyolefin resin, silica powder, plasticizer and glass flake of 90% by weight or more, a content of polyolefin resin of 20 to 60% by weight, and a content of silica powder. Is 40 to 80% by weight, the plasticizer content is 0 to 30% by weight, and the glass flake content is 2 to 15% by weight of the total content of silica powder and glass flakes.
- the glass flakes in the microporous film have an average thickness of 0.2 to 8 ⁇ m, and the glass flakes in the microporous film having a particle size of 10 ⁇ m or more have an average particle size of 20 ⁇ m or more.
- the plane direction is arranged so as to be substantially oriented in the plane direction of the microporous film, and (the content of glass flakes in the microporous film (% by weight)) / (of the glass flakes in the microporous film)
- the value of average thickness ( ⁇ m) needs to be 1 or more.
- the value of (content of glass flake in microporous film (% by weight)) / (average thickness of glass flake in microporous film ( ⁇ m)) is more preferably 2 or more.
- the glass flake is a material included as an unnecessary obstacle in the original separator made of a microporous film.
- the average particle size is 20 ⁇ m or more (preferably 40 ⁇ m or more, more preferably 60 ⁇ m or more).
- the thickness is as large as 80 ⁇ m or more, or even 100 ⁇ m or more, and the average thickness is 8 ⁇ m or less (preferably 6 ⁇ m or less, further 4 ⁇ m or less, or even 2 ⁇ m or less).
- grains with a particle size of 10 micrometers or more may be substantially orientated in the surface direction of a microporous film.
- the orientation of the glass flakes 80% or more of the particles having a particle size of 10 ⁇ m or more in the microporous film are oriented so that the plane direction thereof is 20 ° or less with respect to the plane direction of the microporous film.
- 90% or more of the glass flakes having a particle size of 10 ⁇ m or more in the microporous film are preferably arranged so that the plane direction is 20 ° or less with respect to the plane direction of the microporous film.
- the glass flakes in the microporous film are arranged such that 95% or more of the particles having a particle diameter of 10 ⁇ m or more have a plane direction with respect to the plane direction of the microporous film. It is more preferable that they are arranged so as to be oriented at 20 ° or less. Alternatively, 80% or more of the glass flakes having a particle size of 10 ⁇ m or more in the microporous film are arranged so that the plane direction is oriented at 10 ° or less with respect to the plane direction of the microporous film.
- the glass flakes having a particle size of 10 ⁇ m or more in the microporous film are arranged so that the plane direction is oriented at 10 ° or less with respect to the plane direction of the microporous film. More preferably, 95% or more of the glass flakes having a particle size of 10 ⁇ m or more in the microporous film are oriented so that the plane direction is 10 ° or less with respect to the plane direction of the microporous film. It is more preferable that they are arranged as described above.
- the glass flakes are dispersed and arranged as uniformly as possible in the microporous film so that the minimum necessary amount that can exhibit a sufficient dendrite short-circuit suppressing effect can be suppressed as low as possible so that deterioration of electrical resistance can be suppressed.
- the minimum necessary amount that can exhibit a sufficient dendrite short-circuit suppressing effect can be suppressed as low as possible so that deterioration of electrical resistance can be suppressed.
- the minimum necessary amount that can exhibit a sufficient dendrite short-circuit suppressing effect can be suppressed as low as possible so that deterioration of electrical resistance can be suppressed.
- it becomes easy to form a portion where the packing density of glass flakes is locally low and as a result, dendrite shorts are likely to occur, Battery life due to dendrite shorts is likely to occur.
- the dendrite short phenomenon is a phenomenon that leads to a short circuit when the dendrite that is a dendritic precipitate due to lead penetrates the separator in the thickness direction and communicates between the positive and negative electrodes (conducts).
- the battery life is not immediately reached when the first dendrite first conducts.
- the dendrite that just caused the first conduction does not form a solid connection with the whole dendrite (full length) connected to a perfect state, but it is a level that "it happened to be instantaneously connected" It is in a state that is nothing but an unstable connection. Therefore, the first dendrite happens to be turned off immediately after the first conduction by chance, and returned to the non-conducting state.
- the average particle size of the glass flakes as a raw material exceeds 800 ⁇ m, the uniform dispersibility of the glass flakes in the microporous film tends to deteriorate, so it becomes difficult to improve the dendrite short-circuit suppressing effect, and is less than 20 ⁇ m. Therefore, it becomes difficult to make the hole route complicated (bypass), and the dendrite short-circuit suppressing effect cannot be sufficiently exhibited.
- the average particle diameter of the glass flakes as a raw material is preferably 600 ⁇ m or less, more preferably 400 ⁇ m or less, and even more preferably 200 ⁇ m or less, 40 ⁇ m or more, further 60 ⁇ m or more, or even 80 ⁇ m or more, or even more.
- each raw material is as close to a uniform dispersion state as possible by stirring and mixing a predetermined amount of each raw material in advance with a special mixer Even if the glass flakes can secure high uniform dispersibility, there is no problem. However, since the glass flakes are easily crushed in the subsequent melt-kneading film forming step, each particle is in a uniformly dispersed state before being crushed.
- the average particle diameter of the glass flakes having a particle diameter of 10 ⁇ m or more in the microporous film is more preferably 40 ⁇ m or more, further 60 ⁇ m or more, further 80 ⁇ m or more, and even more preferably 100 ⁇ m or more.
- the thickness of the glass flake is basically the same as the thickness when the raw material is included in the microporous film. If the average thickness of the glass flakes exceeds 8 ⁇ m, the minimum required amount of glass flakes to exert a sufficient dendrite short-circuit suppressing effect increases, resulting in an increase in the glass flake content and electrical resistance. Is likely to get worse. Glass flakes are positioned as raw materials that replace some silica powders that are originally used as inorganic powders, which are one of the main raw materials that make up microporous films, and combine silica powder and glass flakes. In addition, since the concept of the content of the inorganic powder (whole) is not different from the conventional one, the silica powder content decreases as the glass flake content increases.
- the silica powder is a secondary particle formed by agglomeration of fine primary particles to form a powder, and each of the powders has a fine porous structure. Since the electrolyte ions can pass through the individual powder, even if the silica powder intervenes in the voids that become the communication holes in the microporous film, the flow of the electrolyte ions is hardly hindered and the electrical resistance is deteriorated. Hateful.
- glass flakes are usually particles that do not have an agglomerated structure like silica powder or a laminated structure like mica, and exist as primary particles, and each particle is like a silica powder.
- the average thickness of the glass flakes is more preferably 6 ⁇ m or less, further 4 ⁇ m or less, and even more preferably 2 ⁇ m or less.
- the average thickness of the glass flakes is less than 0.2 ⁇ m, the unit price of the material becomes too high, and the glass flakes are easily crushed in the process of melting and kneading the raw material composition containing the glass flakes. Since the uniform dispersibility of the glass flakes in the porous film is likely to deteriorate, it becomes difficult to improve the dendrite short-circuit suppressing effect. For this reason, the average thickness of the glass flakes is more preferably 0.4 ⁇ m or more, further 0.6 ⁇ m or more, and even more preferably 0.8 ⁇ m or more.
- the purpose of glass flakes is to provide a function as an obstacle that makes the pore structure in the thickness direction (hole path) of the microporous film complicated (by detour) without blocking the hole path. Therefore, the glass flakes are arranged so that the plane direction is substantially oriented in the plane direction of the microporous film as much as possible.
- the glass flakes in the melt-kneaded product are subsequently processed into a thickness of 0.1 to 0.3 mm (extrusion to rolling) It is easy to orientate in the sheet surface direction, and even in the microporous film, it is easy to arrange so that the surface direction is substantially oriented in the surface direction of the microporous film.
- the average particle diameter of the glass flakes as a raw material is less than 20 ⁇ m, it is difficult to arrange the glass flakes so that the plane direction is substantially oriented in the plane direction of the microporous film.
- the average particle diameter of the glass flakes as a raw material is more preferably 40 ⁇ m or more, further 60 ⁇ m or more, still more 80 ⁇ m or more, and even more preferably 100 ⁇ m or more.
- the average thickness of the glass flakes as a raw material is 0.2 to 8 ⁇ m
- the glass flakes in the melt-kneaded product are subjected to film forming treatment (extrusion to rolling molding) to a subsequent thickness of 0.1 to 0.3 mm. ) Is easily oriented in the sheet surface direction, and even in the microporous film, the surface direction is easily arranged so as to be substantially oriented in the surface direction of the microporous film.
- the average thickness of the glass flakes as a raw material is more than 8 ⁇ m, it is difficult to dispose the glass flake so that the surface direction is substantially oriented in the surface direction of the microporous film.
- the average thickness of the glass flakes as a raw material is more preferably 6 ⁇ m or less, further 4 ⁇ m or less, and even more preferably 2 ⁇ m or less.
- the glass flakes are dispersed and arranged as uniformly as possible in the microporous film, thereby efficiently exhibiting a high dendrite short-circuit suppressing effect and contributing to a low deterioration of electrical resistance.
- mica which is a flaky or plate-like inorganic substance having a large particle size and a small thickness, is self-forming (primary particles are dispersed in water or liquid). However, it does not have such a self-forming property.
- the glass flakes (primary particles) of the present invention are present in a dispersed state without agglomeration in water or in a liquid, and have a property of existing in a dispersed state without agglomeration even after drying. Therefore, even if the glass flakes of the present invention are melt-kneaded together with polyolefin resin, silica powder, plasticizer, etc., glass flakes (primary particles) exist in a dispersed state without agglomeration. The glass flakes (primary particles) are arranged in a dispersed state without agglomeration.
- the separator in order to suppress the phenomenon of simultaneous occurrence of dendritic shorts at a plurality of locations and reaching the battery life, in the thickness direction of the microporous film (perpendicular to the film surface) While it is required not to increase the portion where the filling density of the local glass flakes extending linearly (through) is as low as possible, it is required to minimize the deterioration of electrical resistance due to the filling of the glass flakes. Therefore, it is required to dispose the obstacle optimally and efficiently in the microporous film, and a highly uniform dispersibility of the glass flakes is required.
- a silane coupling agent is added in an amount of 0 to 3% by weight (solid content) in the raw material composition.
- solid content 0% by weight (solid content) is suggested because when the desired uniform dispersibility can be obtained without adding a silane coupling agent, the harmful effect (the material unit price is very high). This is because it is not necessary to darely include a silane coupling agent having a high (which reduces the hydrophilicity of the silica powder).
- the silane coupling agent has a function of adhering the inorganic surface and the organic surface to each other, each of the glass flakes in the process of preparing the raw material composition (raw material mixture) and in the process of melting and kneading the raw material composition.
- the glass flakes have a high degree of uniform dispersibility in the melt-kneaded product or the film-formed sheet as long as uniform melting and kneading is performed. Dispersed and arranged (except when the glass flakes are easily crushed in the melt-kneading film forming process after the raw material mixture is prepared).
- the silane coupling agent (solid content) is preferably contained in an amount of 0.1 to 3% by weight in the raw material composition.
- the content of the silane coupling agent (solid content) in the raw material composition is 0.1% by weight or more, the effect of enhancing the uniform dispersibility of the glass flakes in the microporous film is easily exhibited.
- the silane coupling agent tends to exert a surface modifying action to make the hydrophilic group (—OH group) of the surface of the silica powder hydrophobic in the raw material composition.
- the hydrophilicity (wetting property with respect to the sulfuric acid electrolyte) of the separator made of a microporous film is lowered, which becomes a cause of deterioration of initial electrical resistance.
- the content of the silane coupling agent (solid content) in the raw material composition is more preferably 2% by weight or less, and further preferably 1% by weight or less of the content of the polyolefin resin.
- Glass flakes are used based on the above conditions, and the necessary amount thereof is 2 to 15% by weight of the total content of silica powder and glass flakes in the raw material composition, as described above.
- the film contains 2 to 15% by weight of the total content of silica powder and glass flakes.
- the content of glass flakes is less than 2% by weight of the total content of silica powder and glass flakes, it is difficult to obtain a sufficient dendrite short-circuit suppression effect (the reliability of the dendrite short-circuit suppression effect is reduced). If it exceeds 15% by weight, the electrical resistance tends to deteriorate.
- glass flake is a raw material used by replacing a part of silica powder originally used as an inorganic powder which is one of main raw materials constituting a microporous film. Since the concept of the content of the inorganic powder (total) combined with the glass flakes is not different from the conventional one, when the glass flake content increases, the silica powder content decreases.
- the silica powder is a secondary particle formed by agglomeration of fine primary particles to form a powder, and each of the powders has a fine porous structure.
- the electrolyte ions can pass through the individual powder, even if the silica powder intervenes in the voids that become the communication holes in the microporous film, the flow of the electrolyte ions is hardly hindered and the electrical resistance is deteriorated. Hateful.
- glass flakes are usually particles that do not have an agglomerated structure like silica powder or a laminated structure like mica, and exist as primary particles, and each particle is like a silica powder. Since it does not have a (fine) porous structure, electrolyte ions cannot pass through the particles, and if glass flakes intervene in the voids that become communication holes in the microporous film, the electrolyte ions can be circulated.
- the average thickness of the glass flakes in the raw material composition and in the microporous film is 2 ⁇ m or less, and the content of the glass flakes is the total content of the silica powder and the glass flakes in the raw material composition.
- the value of (average thickness ( ⁇ m) of glass flakes in the microporous film) is preferably 10 or less.
- alumina, boehmite and the like are flaky or plate-like inorganic substances that do not have self-forming properties.
- natural products contain impurities such as iron and magnesium, and there is a risk that these components may adversely affect the battery.
- alumina or the like is a very expensive material compared to glass, and such an expensive material cannot be used for a lead storage battery, which is characterized by being cheaper than an alkaline battery or a lithium ion battery.
- glass is inexpensive, has long been used for separators and the like as a member for lead-acid batteries, has a high record of safety, and does not contain components such as iron and magnesium that adversely affect the battery.
- the glass flake is preferably made of an acid-resistant C glass composition in consideration of the use as a lead-acid battery separator using a sulfuric acid electrolyte.
- the base thickness of the microporous film is 0.1 to 0.3 mm, but if it exceeds 0.3 mm, the electrical resistance deteriorates, and if it is less than 0.1 mm, good short circuit resistance (dendrite short and Separately, holes may open or crack due to weak parts of the local substrate, high pressure from the convex part of the electrode plate, impact or piercing, oxidation wear due to oxidation power from the electrode plate, etc. Normal short circuit caused) cannot be maintained.
- the porosity (mercury intrusion method) of the microporous film is 50% by volume or more, so that the internal resistance (electrical resistance) can be kept low as a lead-acid battery separator, contributing to higher performance of the lead-acid battery. . Therefore, the porosity of the microporous film (mercury intrusion method) is preferably 60 to 90% by volume, more preferably 70 to 90% by volume.
- the method for obtaining the microporous film of the present invention is to remove a part or all of the plasticizer after film formation by melting and kneading the raw material composition mainly composed of polyolefin resin, silica powder and plasticizer. By doing. Thereby, the film
- An example of a specific manufacturing method is shown below. First, a raw material in which various additives (surfactant, antioxidant, weathering agent, etc.) are added to a predetermined amount of polyolefin resin, silica powder, plasticizer, glass flake, silane coupling agent as required.
- a mixer such as a Henschel mixer or a Laedige mixer to obtain a raw material mixture.
- this mixture is put into a twin-screw extruder having a T-die attached to the tip, extruded into a sheet shape while being heated and melted and kneaded, and passed between a pair of forming rolls having a predetermined groove formed in one roll.
- a film-like product is obtained in which a rib having a predetermined shape is integrally formed on one side of the flat sheet.
- this film-like material is immersed in a suitable solvent (for example, n-hexane), and a predetermined amount of mineral oil is extracted and removed, followed by drying, and the desired microporous film is obtained.
- a suitable solvent for example, n-hexane
- the microporous film of the present invention has a total content of polyolefin resin, silica powder, plasticizer and glass flake of 90% by weight or more, a content of polyolefin resin of 20 to 60% by weight, and a silica powder content.
- the amount is 40 to 80% by weight
- the plasticizer content is 0 to 30% by weight
- the glass flake content is 2 to 15% by weight of the total content of silica powder and glass flakes.
- the content of the silane coupling agent (solid content) is usually 0 to 6% by weight.
- the polyolefin resin content is less than 20% by weight or the silica powder content is more than 80% by weight, the mechanical strength and oxidation resistance of the microporous film by the polyolefin resin will not be sufficient.
- the polyolefin resin content exceeds 60% by weight or the silica powder content is less than 40% by weight, it is difficult to ensure a large porosity and a fine and complicated pore structure of the microporous film. The good electrical resistance characteristics of the quality film separator cannot be maintained.
- polystyrene resin homopolymers or copolymers such as polyethylene, polypropylene, polybutene, polymethylpentene, and mixtures thereof can be used.
- polyethylene is the main component in terms of moldability and economy.
- Polyethylene has a melt molding temperature lower than that of polypropylene, has good productivity, and can suppress production costs.
- the polyolefin resin has a weight average molecular weight of 500,000 or more, the mechanical strength of the membrane can be ensured even in a microporous film containing a large amount of silica powder.
- the polyolefin resin preferably has a weight average molecular weight of 1,000,000 or more, more preferably 1,500,000 or more.
- Polyolefin-based resins are well mixed with silica powder, maintain strength while bonding the silica powder framework as an adhesive functional material in a microporous film, and are chemically stable and safe. Is expensive.
- silica powder those having a fine particle size and having a pore structure inside or on the surface can be used.
- Silica powder has a wide selection range of various powder characteristics such as particle diameter and specific surface area among inorganic powders, is relatively inexpensive and easily available, and has few impurities.
- the silica powder has a specific surface area of 100 m 2 / g or more, the pore structure of the microporous film is made finer (densified) and complicated to improve permeation short circuit resistance, and the electrolyte solution of the microporous film It is preferable to enhance the hydrophilicity of the microporous film by increasing the holding power and providing a large number of hydrophilic groups (—OH) on the powder surface.
- —OH hydrophilic groups
- the specific surface area of the silica powder is more preferably 150 m 2 / g or more. Moreover, it is preferable that the specific surface area of a silica powder is 400 m ⁇ 2 > / g or less. When the specific surface area of the silica powder exceeds 400 m 2 / g, the surface activity of the particles is high and the cohesive force becomes strong, so that it is difficult to uniformly disperse the silica powder in the microporous film.
- the plasticizer it is preferable to select a material that can be a plasticizer of a polyolefin resin, and various organic liquids that are compatible with the polyolefin resin and can be easily extracted with various solvents can be used. Further, mineral oil such as industrial lubricating oil made of saturated hydrocarbon (paraffin), higher alcohol such as stearyl alcohol, ester plasticizer such as dioctyl phthalate, and the like can be used. Among these, mineral oil is preferable because it can be easily reused.
- the plasticizer is preferably blended in an amount of 30 to 70% by weight in the raw material composition mainly composed of polyolefin resin, silica powder, and plasticizer.
- the plasticizer is made porous by being melted and kneaded with a raw material composition mainly composed of a polyolefin resin, silica powder, and a plasticizer to be formed into a predetermined film shape, and then removed.
- the content of the plasticizer in the microporous film separator may be zero.
- an appropriate amount of a plasticizer such as mineral oil can be contained to contribute to an improvement in oxidation resistance.
- the content of the plasticizer in the separator is preferably 5 to 30% by weight.
- saturated hydrocarbon organic solvents such as hexane, heptane, octane, nonane and decane can be used.
- a surfactant hydrophilic agent
- antioxidant antioxidant
- ultraviolet absorber ultraviolet absorber
- weathering agent lubricant
- antibacterial agent antifungal agent
- pigment dye
- additives such as a colorant, an antifogging agent, and a matting agent may be added (blended) or contained within a range that does not impair the object and effect of the present invention.
- the microporous film of the present invention contains a large amount of silica powder having a large specific surface area and high hydrophilicity, which alone has hydrophilicity, wettability with respect to sulfuric acid electrolyte of a lead storage battery which is an aqueous solution, Sulfuric acid electrolyte has permeability (penetration), but when the sulfuric acid electrolyte is injected into the laminate in which the electrode plate and separator are closely integrated in the battery case,
- the microporous film may contain 0.2 to 7% by weight of a surfactant (solid content). Preferably, it is 0.2 to 5% by weight.
- a method of including the surfactant in the microporous film a method of adding the surfactant in a dispersed state in the raw material composition before film formation (internal addition method), a microporous film from which the plasticizer has been removed by film formation
- an addition method for post-processing (attachment treatment) on the porous film
- a method of adding in advance to the raw material composition is preferred.
- the content (required amount) of the surfactant (solid content) is 0.2 to 7% by weight in the microporous film.
- the content of the surfactant (solid content) is increased beyond this range, the effect of improving the hydrophilicity of the microporous film does not greatly increase, and conversely, the porosity of the microporous film is decreased.
- the internal resistance electrical resistance
- the content of the surfactant (solid content) is more preferably 0.2 to 5% by weight in the microporous film.
- any material that can improve the hydrophilicity of the microporous film may be used, and any of a nonionic surfactant, a cationic surfactant, and an anionic surfactant can be used.
- a nonionic surfactant polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl allyl ethers, fatty acid monoglycerides, sorbitan fatty acid esters and the like can be used.
- As the cationic surfactant aliphatic amine salts, quaternary ammonium salts, polyoxyethylene alkylamines, alkylamine oxides and the like can be used.
- alkyl sulfonate alkyl benzene sulfonate, alkyl naphthalene sulfonate, alkyl sulfosuccinate and the like can be used.
- a high hydrophilicity can be imparted with a small amount of addition to the polyolefin-based resin, and a surfactant is added to the raw material composition in advance because it has a relatively high heat resistance.
- Alkylsulfosuccinate is preferred because it can be produced (manufactured by heat melt molding).
- Example 1 1000 parts by weight of an ultrahigh molecular weight polyethylene resin powder (melting point: about 135 ° C.) having a weight average molecular weight of 1.5 million as a polyolefin resin, 2516 parts by weight of silica fine powder having a specific surface area of 200 m 2 / g by BET method, and a plasticizer
- a surfactant 5208 parts by weight of paraffinic mineral oil, 109 parts by weight of dialkylsulfosuccinic acid sodium salt (solid content) as a surfactant, and a self-forming film comprising a C glass composition having an average particle diameter of 250 ⁇ m and an average thickness of 1.5 ⁇ m 78 parts by weight of glass flakes having no properties were mixed with a Ladige mixer, and this raw material composition was extruded into a sheet while heating and kneading using a twin screw extruder having a T die attached to the
- the roll is passed through a pair of forming rolls in which a predetermined groove for a main rib for electrode plate contact is engraved, and is predetermined on one surface of the flat sheet.
- the Jo of the electrode plate abutment main ribs to obtain a film-like material was molded integrally.
- this film-like product is dipped in n-hexane, and a predetermined amount of paraffinic mineral oil is extracted and dried, followed by drying, 22.9% by weight of polyethylene resin, 57.5% by weight of fine silica powder, paraffin Mineral oil 16.0% by weight, surfactant (solid content) 1.8% by weight, glass flakes 1.8% by weight, base thickness is 0.20mm, porosity by mercury intrusion method A ribbed microporous film having 60% by volume, an average pore diameter of 0.09 ⁇ m by mercury intrusion method, and a maximum pore diameter of 0.65 ⁇ m by mercury intrusion method was obtained. This was used as the lead-acid battery separator of Example 1.
- Example 2 1000 parts by weight of ultrahigh molecular weight polyethylene resin powder (melting point: about 135 ° C.) having a weight average molecular weight of 1.5 million as a polyolefin resin, 2412 parts by weight of silica fine powder having a specific surface area of 200 m 2 / g by BET method, and a plasticizer
- a surfactant 4993 parts by weight of paraffinic mineral oil, 109 parts by weight of dialkylsulfosuccinic acid sodium salt (solid content) as a surfactant, and a self-forming film comprising a C glass composition having an average particle size of 250 ⁇ m and an average thickness of 1.5 ⁇ m 182 parts by weight of glass flakes having no properties were mixed with a Ladige mixer, and this raw material composition was extruded into a sheet while heating and kneading using a twin screw extruder having a T die attached to the tip.
- the roll is passed between a pair of forming rolls with predetermined grooves for the main ribs for electrode plate contact, and placed on one side of the flat sheet.
- the electrode plate abutment main rib shape to obtain a film-like material was molded integrally.
- this film-like product is dipped in n-hexane, and a predetermined amount of paraffinic mineral oil is extracted and dried, followed by drying, 22.9% by weight of polyethylene resin, 55.2% by weight of fine silica powder, paraffin Mineral oil 16.0% by weight, surfactant (solid content) 1.8% by weight, glass flakes 4.1% by weight, base thickness 0.20mm, porosity by mercury intrusion method
- a ribbed microporous film having a volume of 58% by volume, an average pore diameter of 0.09 ⁇ m by mercury intrusion method, and a maximum pore diameter of 0.65 ⁇ m by mercury intrusion method was obtained. This was used as the lead-acid battery separator of Example 2.
- Example 3 1000 parts by weight of ultrahigh molecular weight polyethylene resin powder (melting point: about 135 ° C.) having a weight average molecular weight of 1.5 million as a polyolefin resin, 2282 parts by weight of silica fine powder having a specific surface area of 200 m 2 / g by BET method, and a plasticizer
- a surfactant 4724 parts by weight of paraffinic mineral oil, 109 parts by weight of dialkylsulfosuccinic acid sodium salt (solid content) as a surfactant, and a self-forming film comprising a C glass composition having an average particle diameter of 250 ⁇ m and an average thickness of 1.5 ⁇ m 311 parts by weight of glass flakes having no properties were mixed with a Ladige mixer, and this raw material composition was extruded into a sheet while heating and kneading using a twin screw extruder having a T die attached to the tip.
- the roll is passed between a pair of forming rolls with predetermined grooves for the main ribs for electrode plate contact, and placed on one side of the flat sheet.
- the electrode plate abutment main rib shape to obtain a film-like material was molded integrally.
- this film-like product is immersed in n-hexane, a predetermined amount of paraffinic mineral oil is extracted and removed, and dried to obtain 22.9% by weight of polyethylene resin, 52.2% by weight of fine silica powder, paraffin.
- Mineral base oil 16.0 wt%, surfactant (solid content) 1.8 wt%, glass flakes 7.1 wt%, base thickness is 0.20mm, porosity by mercury intrusion method A ribbed microporous film having 53% by volume, an average pore diameter of 0.09 ⁇ m by the mercury intrusion method, and a maximum pore diameter of 0.65 ⁇ m by the mercury intrusion method was obtained. This was used as the lead-acid battery separator of Example 3.
- Example 4 1000 parts by weight of ultrahigh molecular weight polyethylene resin powder (melting point: about 135 ° C.) having a weight average molecular weight of 1.5 million as a polyolefin resin, 2412 parts by weight of silica fine powder having a specific surface area of 200 m 2 / g by BET method, and a plasticizer
- a surfactant 4993 parts by weight of paraffinic mineral oil, 109 parts by weight of dialkylsulfosuccinic acid sodium salt (solid content) as a surfactant, and a self-forming film comprising a C glass composition having an average particle size of 250 ⁇ m and an average thickness of 1.5 ⁇ m
- a twin screw extruder in which 182 parts by weight of glass flakes having no properties and 18 parts by weight of a silane coupling agent (solid content) are mixed by a Laedige mixer, and this raw material composition is attached to the tip with a T die.
- Example 5 1000 parts by weight of ultrahigh molecular weight polyethylene resin powder (melting point: about 135 ° C.) having a weight average molecular weight of 1.5 million as a polyolefin resin, 2412 parts by weight of silica fine powder having a specific surface area of 200 m 2 / g by BET method, and a plasticizer
- a surfactant 4993 parts by weight of paraffinic mineral oil, 109 parts by weight of dialkylsulfosuccinic acid sodium salt (solid content) as a surfactant, and a self-forming film comprising a C glass composition having an average particle size of 250 ⁇ m and an average thickness of 1.5 ⁇ m
- a twin screw extruder in which 182 parts by weight of glass flakes having no properties and 70 parts by weight of a silane coupling agent (solid content) are mixed with a Laedige mixer, and this raw material composition is attached to the tip with a T die.
- this film-like product is immersed in n-hexane, and a predetermined amount of paraffinic mineral oil is extracted and removed, followed by drying, 22.4% by weight of polyethylene resin, 54.1% by weight of fine silica powder, paraffin Base composed of 16.0% by weight of mineral oil, 1.8% by weight of surfactant (solid content), 4.1% by weight of glass flake, and 1.6% by weight of silane coupling agent (solid content)
- paraffin Base composed of 16.0% by weight of mineral oil, 1.8% by weight of surfactant (solid content), 4.1% by weight of glass flake, and 1.6% by weight of silane coupling agent (solid content)
- a ribbed microporous film having a thickness of 0.20 mm, a porosity of 58% by mercury intrusion method, an average pore diameter of 0.09 ⁇ m by mercury intrusion method, and a maximum pore diameter of 0.65 ⁇ m by mercury intrusion method was obtained. . This was used as the lead-acid battery separator of Example 5.
- Example 6 1000 parts by weight of ultrahigh molecular weight polyethylene resin powder (melting point: about 135 ° C.) having a weight average molecular weight of 1.5 million as a polyolefin resin, 2282 parts by weight of silica fine powder having a specific surface area of 200 m 2 / g by BET method, and a plasticizer
- a surfactant 4724 parts by weight of paraffinic mineral oil, 109 parts by weight of dialkylsulfosuccinic acid sodium salt (solid content) as a surfactant, and a self-forming film comprising a C glass composition having an average particle diameter of 250 ⁇ m and an average thickness of 1.5 ⁇ m
- a twin-screw extruder in which 311 parts by weight of glass flakes having no properties and 71 parts by weight of a silane coupling agent (solid content) are mixed by a Laedige mixer, and this raw material composition is attached to the tip with a T die.
- this film-like product is immersed in n-hexane, a predetermined amount of paraffinic mineral oil is extracted and removed, and dried, 22.4% by weight of polyethylene resin, 51.2% by weight of fine silica powder, paraffin Base consisting of 16.0% by weight of mineral oil, 1.8% by weight of surfactant (solid content), 7.0% by weight of glass flakes, 1.6% by weight of silane coupling agent (solid content)
- paraffin Base consisting of 16.0% by weight of mineral oil, 1.8% by weight of surfactant (solid content), 7.0% by weight of glass flakes, 1.6% by weight of silane coupling agent (solid content)
- a ribbed microporous film having a thickness of 0.20 mm, a porosity of 53% by mercury intrusion method, an average pore diameter of 0.09 ⁇ m by mercury intrusion method, and a maximum pore diameter of 0.65 ⁇ m by mercury intrusion method was obtained. . This was used as the lead-acid battery separator of Example 6.
- Example 7 1000 parts by weight of ultrahigh molecular weight polyethylene resin powder (melting point: about 135 ° C.) having a weight average molecular weight of 1.5 million as a polyolefin resin, 2412 parts by weight of silica fine powder having a specific surface area of 200 m 2 / g by BET method, and a plasticizer
- a surfactant 4993 parts by weight of a paraffinic mineral oil, 109 parts by weight of a dialkylsulfosuccinic acid sodium salt (solid content) as a surfactant, and a self-forming film comprising a C glass composition having an average particle diameter of 250 ⁇ m and an average thickness of 0.5 ⁇ m 182 parts by weight of glass flakes having no properties were mixed with a Ladige mixer, and this raw material composition was extruded into a sheet while heating and kneading using a twin screw extruder having a T die attached to the tip.
- the roll is passed between a pair of forming rolls with predetermined grooves for the main ribs for electrode plate contact, and placed on one side of the flat sheet.
- the electrode plate abutment main rib shape to obtain a film-like material was molded integrally.
- this film-like product is dipped in n-hexane, and a predetermined amount of paraffinic mineral oil is extracted and dried, followed by drying, 22.9% by weight of polyethylene resin, 55.2% by weight of fine silica powder, paraffin Mineral oil 16.0% by weight, surfactant (solid content) 1.8% by weight, glass flakes 4.1% by weight, base thickness 0.20mm, porosity by mercury intrusion method
- a ribbed microporous film having a volume of 58% by volume, an average pore diameter of 0.09 ⁇ m by mercury intrusion method, and a maximum pore diameter of 0.65 ⁇ m by mercury intrusion method was obtained. This was used as the lead-acid battery separator of Example 7.
- Example 8 1000 parts by weight of an ultrahigh molecular weight polyethylene resin powder (melting point: about 135 ° C.) having a weight average molecular weight of 1.5 million as a polyolefin resin, 2516 parts by weight of silica fine powder having a specific surface area of 200 m 2 / g by BET method, and a plasticizer
- a surfactant 5208 parts by weight of a paraffinic mineral oil, 109 parts by weight of a dialkylsulfosuccinic acid sodium salt (solid content) as a surfactant, and a self-forming film comprising a C glass composition having an average particle diameter of 250 ⁇ m and an average thickness of 0.5 ⁇ m 78 parts by weight of glass flakes having no properties were mixed with a Ladige mixer, and this raw material composition was extruded into a sheet while heating and kneading using a twin screw extruder having a T die attached to the tip.
- the roll is passed through a pair of forming rolls in which a predetermined groove for a main rib for electrode plate contact is engraved, and is predetermined on one surface of the flat sheet.
- the Jo of the electrode plate abutment main ribs to obtain a film-like material was molded integrally.
- this film-like product is immersed in n-hexane, a predetermined amount of paraffinic mineral oil is extracted and removed, and dried to obtain 22.9% by weight of polyethylene resin, 57.6% by weight of fine silica powder, paraffin.
- Example 9 1000 parts by weight of ultrahigh molecular weight polyethylene resin powder (melting point: about 135 ° C.) having a weight average molecular weight of 1.5 million as a polyolefin resin, 2282 parts by weight of silica fine powder having a specific surface area of 200 m 2 / g by BET method, and a plasticizer
- a surfactant 4724 parts by weight of a paraffinic mineral oil, 109 parts by weight of a dialkylsulfosuccinic acid sodium salt (solid content) as a surfactant, and a self-forming film comprising a C glass composition having an average particle diameter of 250 ⁇ m and an average thickness of 6.0 ⁇ m 311 parts by weight of glass flakes having no properties were mixed with a Ladige mixer, and this raw material composition was extruded into a sheet while heating and kneading using a twin screw extruder having a T die attached to the tip.
- the roll is passed between a pair of forming rolls with predetermined grooves for the main ribs for electrode plate contact, and placed on one side of the flat sheet.
- the electrode plate abutment main rib shape to obtain a film-like material was molded integrally.
- this film-like product is immersed in n-hexane, a predetermined amount of paraffinic mineral oil is extracted and removed, and dried to obtain 22.9% by weight of polyethylene resin, 52.2% by weight of fine silica powder, paraffin.
- Mineral base oil 16.0 wt%, surfactant (solid content) 1.8 wt%, glass flakes 7.1 wt%, base thickness is 0.20mm, porosity by mercury intrusion method A ribbed microporous film having 53% by volume, an average pore diameter of 0.09 ⁇ m by the mercury intrusion method, and a maximum pore diameter of 0.65 ⁇ m by the mercury intrusion method was obtained. This was used as the lead-acid battery separator of Example 9.
- Example 10 1000 parts by weight of ultrahigh molecular weight polyethylene resin powder (melting point: about 135 ° C.) having a weight average molecular weight of 1.5 million as a polyolefin resin, 2412 parts by weight of silica fine powder having a specific surface area of 200 m 2 / g by BET method, and a plasticizer
- a surfactant 4993 parts by weight of a paraffinic mineral oil, 109 parts by weight of a dialkylsulfosuccinic acid sodium salt (solid content) as a surfactant, and a self-forming film comprising a C glass composition having an average particle diameter of 50 ⁇ m and an average thickness of 1.5 ⁇ m 182 parts by weight of glass flakes having no properties were mixed with a Ladige mixer, and this raw material composition was extruded into a sheet while heating and kneading using a twin screw extruder having a T die attached to the tip.
- the roll is passed through a pair of forming rolls in which a predetermined groove for a main rib for electrode plate contact is engraved, and is predetermined on one surface of the flat sheet.
- the Jo of the electrode plate abutment main ribs to obtain a film-like material was molded integrally.
- this film-like product is dipped in n-hexane, and a predetermined amount of paraffinic mineral oil is extracted and dried, followed by drying, 22.9% by weight of polyethylene resin, 55.2% by weight of fine silica powder, paraffin Mineral oil 16.0% by weight, surfactant (solid content) 1.8% by weight, glass flakes 4.1% by weight, base thickness 0.20mm, porosity by mercury intrusion method
- Example 11 1000 parts by weight of ultrahigh molecular weight polyethylene resin powder (melting point: about 135 ° C.) having a weight average molecular weight of 1.5 million as a polyolefin resin, 2412 parts by weight of silica fine powder having a specific surface area of 200 m 2 / g by BET method, and a plasticizer
- a surfactant 4993 parts by weight of a paraffinic mineral oil, 109 parts by weight of a dialkylsulfosuccinic acid sodium salt (solid content) as a surfactant, and a self-forming film comprising a C glass composition having an average particle size of 140 ⁇ m and an average thickness of 1.5 ⁇ m 182 parts by weight of glass flakes having no properties were mixed with a Ladige mixer, and this raw material composition was extruded into a sheet while heating and kneading using a twin screw extruder having a T die attached to the tip.
- the roll is passed between a pair of forming rolls with predetermined grooves for the main ribs for electrode plate contact, and placed on one side of the flat sheet.
- the electrode plate abutment main rib shape to obtain a film-like material was molded integrally.
- this film-like product is dipped in n-hexane, and a predetermined amount of paraffinic mineral oil is extracted and dried, followed by drying, 22.9% by weight of polyethylene resin, 55.2% by weight of fine silica powder, paraffin Mineral oil 16.0% by weight, surfactant (solid content) 1.8% by weight, glass flakes 4.1% by weight, base thickness 0.20mm, porosity by mercury intrusion method
- a ribbed microporous film having a volume of 58% by volume, an average pore diameter of 0.09 ⁇ m by mercury intrusion method, and a maximum pore diameter of 0.65 ⁇ m by mercury intrusion method was obtained. This was used as the lead-acid battery separator of Example 11.
- Example 12 1000 parts by weight of ultrahigh molecular weight polyethylene resin powder (melting point: about 135 ° C.) having a weight average molecular weight of 1.5 million as a polyolefin resin, 2412 parts by weight of silica fine powder having a specific surface area of 200 m 2 / g by BET method, and a plasticizer
- a surfactant 4993 parts by weight of paraffinic mineral oil, 109 parts by weight of dialkylsulfosuccinic acid sodium salt (solid content) as a surfactant, and a self-forming film comprising a C glass composition having an average particle diameter of 600 ⁇ m and an average thickness of 1.5 ⁇ m 182 parts by weight of glass flakes having no properties were mixed with a Ladige mixer, and this raw material composition was extruded into a sheet while heating and kneading using a twin screw extruder having a T die attached to the tip.
- the roll is passed between a pair of forming rolls with predetermined grooves for the main ribs for electrode plate contact, and placed on one side of the flat sheet.
- the electrode plate abutment main rib shape to obtain a film-like material was molded integrally.
- this film-like product is dipped in n-hexane, and a predetermined amount of paraffinic mineral oil is extracted and dried, followed by drying, 22.9% by weight of polyethylene resin, 55.2% by weight of fine silica powder, paraffin Mineral oil 16.0% by weight, surfactant (solid content) 1.8% by weight, glass flakes 4.1% by weight, base thickness 0.20mm, porosity by mercury intrusion method
- a ribbed microporous film having a volume of 58% by volume, an average pore diameter of 0.09 ⁇ m by mercury intrusion method, and a maximum pore diameter of 0.65 ⁇ m by mercury intrusion method was obtained. This was used as the lead-acid battery separator of Example 12.
- Comparative Example 1 1000 parts by weight of ultrahigh molecular weight polyethylene resin powder (melting point: about 135 ° C.) having a weight average molecular weight of 1.5 million as a polyolefin resin, 2568 parts by weight of silica fine powder having a specific surface area of 200 m 2 / g by BET method, and a plasticizer
- a surfactant 5316 parts by weight of paraffinic mineral oil, 109 parts by weight of dialkylsulfosuccinic acid sodium salt (solid content) as a surfactant, and a self-forming film comprising a C glass composition having an average particle diameter of 250 ⁇ m and an average thickness of 1.5 ⁇ m 26 parts by weight of glass flakes having no properties were mixed with a Ladige mixer, and this raw material composition was extruded into a sheet while heating and kneading using a twin screw extruder having a T die attached to the tip.
- the roll is passed through a pair of forming rolls in which a predetermined groove for a main rib for electrode plate contact is engraved, and is predetermined on one surface of the flat sheet.
- the Jo of the electrode plate abutment main ribs to obtain a film-like material was molded integrally.
- this film-like product is immersed in n-hexane, a predetermined amount of paraffinic mineral oil is extracted and removed, and dried to obtain 22.9% by weight of polyethylene resin, 58.7% by weight of fine silica powder, paraffin.
- Comparative Example 2 1000 parts by weight of ultrahigh molecular weight polyethylene resin powder (melting point: about 135 ° C.) having a weight average molecular weight of 1.5 million as a polyolefin resin, 2075 parts by weight of silica fine powder having a specific surface area of 200 m 2 / g by BET method, and a plasticizer 4295 parts by weight of paraffinic mineral oil, 109 parts by weight of dialkylsulfosuccinic acid sodium salt (solid content) as a surfactant, and a self-forming film comprising a C glass composition having an average particle size of 250 ⁇ m and an average thickness of 1.5 ⁇ m 519 parts by weight of glass flakes having no properties were mixed with a Ladige mixer, and this raw material composition was extruded into a sheet while heating and kneading using a twin screw extruder having a T die attached to the tip.
- the roll is passed between a pair of forming rolls with predetermined grooves for the main ribs for electrode plate contact, and placed on one side of the flat sheet.
- the electrode plate abutment main rib shape to obtain a film-like material was molded integrally.
- this film-like product is immersed in n-hexane, a predetermined amount of paraffinic mineral oil is extracted and removed, and dried to obtain 22.9% by weight of polyethylene resin, 47.4% by weight of fine silica powder, paraffin.
- Mineral base oil 16.0 wt%, surfactant (solid content) 1.8 wt%, glass flakes 11.9 wt%, base thickness 0.20mm, porosity by mercury intrusion method
- a ribbed microporous film having 50% by volume, an average pore diameter of 0.09 ⁇ m by the mercury intrusion method, and a maximum pore diameter of 0.65 ⁇ m by the mercury intrusion method was obtained. This was used as the lead-acid battery separator of Comparative Example 2.
- Comparative Example 3 1000 parts by weight of ultrahigh molecular weight polyethylene resin powder (melting point: about 135 ° C.) having a weight average molecular weight of 1.5 million as a polyolefin resin, 2412 parts by weight of silica fine powder having a specific surface area of 200 m 2 / g by BET method, and a plasticizer
- a surfactant 4993 parts by weight of paraffinic mineral oil, 109 parts by weight of dialkylsulfosuccinic acid sodium salt (solid content) as a surfactant, and a self-forming film comprising a C glass composition having an average particle size of 250 ⁇ m and an average thickness of 1.5 ⁇ m
- a twin-screw extruder in which 182 parts by weight of glass flakes having no properties and 315 parts by weight of a silane coupling agent (solid content) are mixed by a Laedige mixer, and this raw material composition is attached to a tip with a T die.
- Comparative Example 4 1000 parts by weight of ultrahigh molecular weight polyethylene resin powder (melting point: about 135 ° C.) having a weight average molecular weight of 1.5 million as a polyolefin resin, 2282 parts by weight of silica fine powder having a specific surface area of 200 m 2 / g by BET method, and a plasticizer
- a surfactant 4724 parts by weight of a paraffinic mineral oil, 109 parts by weight of a dialkylsulfosuccinic acid sodium salt (solid content) as a surfactant, and a self-forming film comprising a C glass composition having an average particle diameter of 250 ⁇ m and an average thickness of 10.0 ⁇ m 311 parts by weight of glass flakes having no properties were mixed with a Ladige mixer, and this raw material composition was extruded into a sheet while heating and kneading using a twin screw extruder having a T die attached to the tip.
- Mineral base oil 16.0 wt%, surfactant (solid content) 1.8 wt%, glass flakes 7.1 wt%, base thickness is 0.20mm, porosity by mercury intrusion method A ribbed microporous film having 53% by volume, an average pore diameter of 0.09 ⁇ m by the mercury intrusion method, and a maximum pore diameter of 0.65 ⁇ m by the mercury intrusion method was obtained. This was used as the lead-acid battery separator of Comparative Example 4.
- the roll is passed through a pair of forming rolls in which a predetermined groove for a main rib for electrode plate contact is engraved, and is predetermined on one surface of the flat sheet.
- the Jo of the electrode plate abutment main ribs to obtain a film-like material was molded integrally.
- this film-like product is dipped in n-hexane, and a predetermined amount of paraffinic mineral oil is extracted and dried, followed by drying, 22.8% by weight of polyethylene resin, 50.5% by weight of silica fine powder, paraffin Base oil composed of 16.0% by weight of mineral oil, 1.8% by weight of surfactant (solid content) and 8.9% by weight of glass flakes.
- a ribbed microporous film having 51% by volume, an average pore diameter of 0.09 ⁇ m by mercury intrusion method, and a maximum pore diameter of 0.65 ⁇ m by mercury intrusion method was obtained. This was used as the lead-acid battery separator of Comparative Example 5.
- this film-like product is dipped in n-hexane, and a predetermined amount of paraffinic mineral oil is extracted and dried, followed by drying, 22.9% by weight of polyethylene resin, 55.2% by weight of fine silica powder, paraffin Mineral oil 16.0% by weight, surfactant (solid content) 1.8% by weight, glass flakes 4.1% by weight, base thickness 0.20mm, porosity by mercury intrusion method
- a film-like product was obtained by integrally forming and processing a main plate contact main rib having a predetermined shape on the surface.
- this film-like product is immersed in n-hexane, a predetermined amount of paraffinic mineral oil is extracted and removed, and dried to obtain 22.9% by weight of polyethylene resin, 59.3% by weight of fine silica powder, paraffin.
- MD means the production direction of the sheet to be produced
- CD means a direction orthogonal to the MD direction.
- ⁇ Average particle size (glass flake)> Using a high-resolution 3DX ray microscope (manufactured by Rigaku Corporation), a plurality of tomographic images (some of which may include a surface image) are obtained in a direction parallel to the surface direction of the microporous film, and based on this, The particle size of glass flakes (the square root of the area when glass flake primary particles are viewed in plan) is randomly measured (however, only particles having a particle size of 10 ⁇ m or more), the average value is obtained, and the average particle size ( ⁇ m).
- the method for obtaining the average particle size of the glass flakes as the raw material does not follow this method (the definition of the particle size is “the square root of the area when the primary particles of the glass flakes are viewed in plan”).
- the definition of the particle size is “the square root of the area when the primary particles of the glass flakes are viewed in plan”.
- ⁇ Uniform dispersibility (silica fine powder)> Using a high-resolution 3DX-ray microscope (Rigaku Corporation), a plurality of tomographic images are randomly acquired in the direction perpendicular to the surface of the microporous film, and aggregates of silica powder appearing white in the image (relative in this image) The portion having a high electron density appears white, but in the case of the same microporous film, the size and the degree of presence of the aggregate of silica powder appear white due to the relatively high electron density) were evaluated.
- silica powder exists as secondary particles in which primary particles are aggregated, but it is easy to form tertiary particles in which secondary particles are further agglomerated.
- a raw material mixture is prepared by stirring and mixing with a special mixer or the like so as to disperse, but when the raw material mixture is obtained, the tertiary particles (aggregates of secondary particles) of the silica powder are well crushed to obtain secondary particles. Ideally, it should be distributed to the above level, and as close as possible to this state.
- the high uniform dispersibility of the raw material mixture means that the raw material mixture in the microporous film has a high uniform dispersibility (however, glass flakes are crushed in the melt-kneading film forming process after the raw material mixture is prepared). Except in the case of easy-to-break conditions, and high uniform dispersion of silica powder means high uniformity of each raw material including glass flakes (however, melt kneading after preparing the raw material mixture) Except under conditions where glass flakes are easily broken during film formation).
- ⁇ Direction / Angle (Glass Flakes)> Using a high-resolution 3DX-ray microscope (manufactured by Rigaku Corporation), a plurality of tomographic images are obtained randomly in the direction perpendicular to the surface of the microporous film, and based on this, glass flakes (primary particles) appear white in the image 50 directions (angles) were randomly checked (measured) and evaluated (average value was obtained).
- ⁇ Base thickness> Using a dial gauge (Peacock G-6 manufactured by Ozaki Seisakusho Co., Ltd.), arbitrary points and several points of a microporous film (a portion not including rib-like projections when rib-like projections are included) were measured.
- a test piece is cut from the microporous film into a rectangular size of 10 mm ⁇ 70 mm in the MD and CD directions.
- the interval (a) between the grips of the tester is about 50 mm
- a test piece is attached, and a tensile test is performed at a pulling speed of 200 mm per minute.
- the elongation is calculated by dividing the distance (c) by the interval (a) between the grips of the tester.
- a positive electrode and a negative electrode made of a square lead plate of 50 mm ⁇ 50 mm are laminated with a microporous film separator cut into a 70 mm ⁇ 70 mm square shape, concentrically and in a square orientation, and laminated. After applying a pressure of 19.6 kPa to the electrode group consisting of the positive electrode (one piece), the separator (one piece), and the negative electrode (one piece) in the battery case, it was diluted with a specific gravity of 1.300 (20 ° C.).
- the center of the three squares coincide with each other and the sides of the three squares are parallel to each other so that they are placed horizontally in the battery case, and a 5 kg weight is placed on them (at the center of the square).
- a saturated lead sulfate aqueous solution is injected.
- a current of 3.2 mA is applied to the lead electrode plate, and the voltage change is continuously recorded.
- the voltage increases slightly after the start of energization and then gradually decreases. Time is measured until the voltage drops to 70% of the maximum voltage at this time.
- Tables 1 and 2 show the relative values when the value of the conventional example is 100.
- CD direction elongation is almost equivalent to 610 to 650%
- MD direction elongation is slightly reduced to 40 to 52%, but maintains a level without problems as a lead-acid battery separator
- the average pore diameter is Although the same as 0.09 ⁇ m was maintained and the maximum pore diameter was maintained equal to 0.65 ⁇ m, a portion of silica fine powder having numerous fine pores and a large surface area was replaced with glass flakes.
- permeability slightly decreased to 21 to 26 seconds
- electric resistance was slightly increased to 0.0010 to 0.0012 ⁇ ⁇ 100 cm 2 / sheet.
- Glass flakes By replacing it, the effective reinforcement effect to the polyethylene resin base material by the scale-like inorganic substance was exhibited, and the oxidation resistance life was improved to 110 to 150%, and a part of the silica fine powder was replaced.
- An appropriate amount of glass flakes having an average particle diameter of 50 to 600 ⁇ m and an average thickness of 0.5 to 6.0 ⁇ m is added, and the average particle diameter (particles having a particle diameter of 10 ⁇ m or more) is averaged in the microporous film at 40 to 150 ⁇ m.
- Dendrites containing glass flakes having a thickness of 0.5 to 6.0 ⁇ m in a uniformly dispersed state and arranged in an appropriate amount so that the plane direction is substantially oriented in the plane direction of the microporous film Short characteristics improved to 130-150%. Therefore, using the separators of the first to twelfth embodiments of the present invention, a special battery usage environment such as a charge-controlled vehicle or an idling stop vehicle (the battery is not fully charged, and is always charged and discharged repeatedly. When applied to an automotive lead-acid battery that is in a state), it suppresses the occurrence of dendritic shorts and contributes to the suppression of early battery life due to the simultaneous occurrence of dendritic shorts.
- the content of glass flakes in the raw material composition and in the microporous film was as low as 1.0% by weight of the total content of silica fine powder and glass flakes. Although the electrical resistance is prevented from deteriorating with respect to the separator, no improvement in the dendrite short-circuit characteristics is observed.
- the content of glass flakes in the raw material composition and in the microporous film was as high as 20.0% by weight of the total content of silica fine powder and glass flakes. Although the dendrite short property is significantly improved to 150% with respect to the separator, the electric resistance is greatly deteriorated to 0.0016 ⁇ ⁇ 100 cm 2 / sheet.
- the separator of Comparative Example 5 had a glass flake because the average particle size of glass flakes in the raw material composition and the average particle size of glass lakes in the microporous film (particles having a particle size of 10 ⁇ m or more) were as small as 10 ⁇ m.
- the content of the silica is increased to 15.0% by weight of the total content of the silica fine powder and the glass flake, and the surface direction of the glass flake in the microporous film and the surface direction of the microporous film tend to be substantially the same direction.
- the dendrite short characteristic is improved to 140% with respect to the separator of the conventional example, the electrical resistance is greatly deteriorated to 0.0016 ⁇ ⁇ 100 cm 2 / sheet.
- the average particle size of the glass flakes in the raw material composition was as large as 1000 ⁇ m, and the average particle size of the glass flakes in the microporous film (particles having a particle size of 10 ⁇ m or more) was 180 ⁇ m. Therefore, the uniform dispersibility of the glass flakes (primary particles having a particle size of 10 ⁇ m or more) in the microporous film is lowered, and the dendrite short property is only improved by 110% as compared with the conventional separator.
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Abstract
Description
(実施例1)
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2516重量部と、可塑剤としてパラフィン系鉱物オイル5208重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が250μmで平均厚さが1.5μmのCガラス組成からなる自己造膜性を有しないガラスフレーク78重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.9重量%、シリカ微粉体57.5重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク1.8重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が60体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを実施例1の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2412重量部と、可塑剤としてパラフィン系鉱物オイル4993重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が250μmで平均厚さが1.5μmのCガラス組成からなる自己造膜性を有しないガラスフレーク182重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.9重量%、シリカ微粉体55.2重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク4.1重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が58体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを実施例2の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2282重量部と、可塑剤としてパラフィン系鉱物オイル4724重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が250μmで平均厚さが1.5μmのCガラス組成からなる自己造膜性を有しないガラスフレーク311重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.9重量%、シリカ微粉体52.2重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク7.1重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が53体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを実施例3の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2412重量部と、可塑剤としてパラフィン系鉱物オイル4993重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が250μmで平均厚さが1.5μmのCガラス組成からなる自己造膜性を有しないガラスフレーク182重量部と、シランカップリング剤(固形分)18重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.8重量%、シリカ微粉体54.9重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク4.1重量%、シランカップリング剤(固形分)0.4重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が58体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを実施例4の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2412重量部と、可塑剤としてパラフィン系鉱物オイル4993重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が250μmで平均厚さが1.5μmのCガラス組成からなる自己造膜性を有しないガラスフレーク182重量部と、シランカップリング剤(固形分)70重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.4重量%、シリカ微粉体54.1重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク4.1重量%、シランカップリング剤(固形分)1.6重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が58体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを実施例5の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2282重量部と、可塑剤としてパラフィン系鉱物オイル4724重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が250μmで平均厚さが1.5μmのCガラス組成からなる自己造膜性を有しないガラスフレーク311重量部と、シランカップリング剤(固形分)71重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.4重量%、シリカ微粉体51.2重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク7.0重量%、シランカップリング剤(固形分)1.6重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が53体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを実施例6の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2412重量部と、可塑剤としてパラフィン系鉱物オイル4993重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が250μmで平均厚さが0.5μmのCガラス組成からなる自己造膜性を有しないガラスフレーク182重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.9重量%、シリカ微粉体55.2重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク4.1重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が58体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを実施例7の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2516重量部と、可塑剤としてパラフィン系鉱物オイル5208重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が250μmで平均厚さが0.5μmのCガラス組成からなる自己造膜性を有しないガラスフレーク78重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.9重量%、シリカ微粉体57.6重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク1.7重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が59体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを実施例8の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2282重量部と、可塑剤としてパラフィン系鉱物オイル4724重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が250μmで平均厚さが6.0μmのCガラス組成からなる自己造膜性を有しないガラスフレーク311重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.9重量%、シリカ微粉体52.2重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク7.1重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が53体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを実施例9の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2412重量部と、可塑剤としてパラフィン系鉱物オイル4993重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が50μmで平均厚さが1.5μmのCガラス組成からなる自己造膜性を有しないガラスフレーク182重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.9重量%、シリカ微粉体55.2重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク4.1重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が58体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを実施例10の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2412重量部と、可塑剤としてパラフィン系鉱物オイル4993重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が140μmで平均厚さが1.5μmのCガラス組成からなる自己造膜性を有しないガラスフレーク182重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.9重量%、シリカ微粉体55.2重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク4.1重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が58体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを実施例11の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2412重量部と、可塑剤としてパラフィン系鉱物オイル4993重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が600μmで平均厚さが1.5μmのCガラス組成からなる自己造膜性を有しないガラスフレーク182重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.9重量%、シリカ微粉体55.2重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク4.1重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が58体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを実施例12の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2568重量部と、可塑剤としてパラフィン系鉱物オイル5316重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が250μmで平均厚さが1.5μmのCガラス組成からなる自己造膜性を有しないガラスフレーク26重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.9重量%、シリカ微粉体58.7重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク0.6重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が61体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを比較例1の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2075重量部と、可塑剤としてパラフィン系鉱物オイル4295重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が250μmで平均厚さが1.5μmのCガラス組成からなる自己造膜性を有しないガラスフレーク519重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.9重量%、シリカ微粉体47.4重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク11.9重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が50体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを比較例2の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2412重量部と、可塑剤としてパラフィン系鉱物オイル4993重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が250μmで平均厚さが1.5μmのCガラス組成からなる自己造膜性を有しないガラスフレーク182重量部と、シランカップリング剤(固形分)315重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂21.0重量%、シリカ微粉体50.8重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク3.8重量%、シランカップリング剤(固形分)6.6重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が58体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを比較例3の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2282重量部と、可塑剤としてパラフィン系鉱物オイル4724重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が250μmで平均厚さが10.0μmのCガラス組成からなる自己造膜性を有しないガラスフレーク311重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.9重量%、シリカ微粉体52.2重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク7.1重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が53体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを比較例4の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2210重量部と、可塑剤としてパラフィン系鉱物オイル4580重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が10μmで平均厚さが1.5μmのCガラス組成からなる自己造膜性を有しないガラスフレーク390重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.8重量%、シリカ微粉体50.5重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク8.9重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が51体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを比較例5の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2412重量部と、可塑剤としてパラフィン系鉱物オイル4993重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部と、平均粒径が1000μmで平均厚さが1.5μmのCガラス組成からなる自己造膜性を有しないガラスフレーク182重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.9重量%、シリカ微粉体55.2重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%、ガラスフレーク4.1重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が58体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを比較例6の鉛蓄電池用セパレータとした。
ポリオレフィン系樹脂として重量平均分子量が150万の超高分子量ポリエチレン樹脂粉体(融点約135℃)1000重量部と、BET法による比表面積が200m2/gのシリカ微粉体2590重量部と、可塑剤としてパラフィン系鉱物オイル5380重量部と、界面活性剤としてジアルキルスルホコハク酸ナトリウム塩(固形分)109重量部とをレーディゲミキサーにて混合し、この原料組成物を先端にTダイを取り付けた二軸押出機を用い加熱溶融混練しながらシート状に押し出し、一方のロールに極板当接用主リブのための所定の溝を刻設した一対の成形ロール間を通し、平板状シートの一方の面に所定形状の極板当接用主リブを一体に成形加工したフィルム状物を得た。次に、このフィルム状物をn-ヘキサン中に浸漬し、パラフィン系鉱物オイルの所定量を抽出除去し、乾燥させて、ポリエチレン樹脂22.9重量%、シリカ微粉体59.3重量%、パラフィン系鉱物オイル16.0重量%、界面活性剤(固形分)1.8重量%とで構成される、ベース厚さが0.20mm、水銀圧入法による空隙率が62体積%、水銀圧入法による平均細孔径が0.09μm、水銀圧入法による最大孔径が0.65μmのリブ付き微多孔質フィルムを得た。これを従来例の鉛蓄電池用セパレータとした。
〈平均粒径(ガラスフレーク)〉
高分解能3DX線顕微鏡(リガク社製)を使い、微多孔質フィルムの面方向と平行方向に断層画像(一部、表面画像を含んでもよい)をランダムに複数個取得し、これを基に、ガラスフレークの粒径(ガラスフレークの一次粒子を平面視したときのその面積の平方根)をランダムに50個測定し(但し、粒径10μm以上の粒子のみ)、平均値を求め、平均粒径(μm)とした。尚、原材料としてのガラスフレークの平均粒径の求め方は、この方法に従わない(粒径の定義は、「ガラスフレークの一次粒子を平面視したときのその面積の平方根」であり変わらない)。
〈均一分散性(シリカ微粉体)〉
高分解能3DX線顕微鏡(リガク社製)を使い、微多孔質フィルムの面方向と垂直方向に断層画像をランダムに複数個取得し、画像中に白く写るシリカ粉体の凝集体(同画像では相対的に電子密度が高い部分が白く写るが、同微多孔質フィルムの場合はシリカ粉体の凝集体が相対的に電子密度が高いため白く写る)の大きさや存在度合いをチェックし、評価した。通常、シリカ粉体は、一次粒子が凝集した二次粒子として存在するが、二次粒子が更に凝集した三次粒子も形成しやすく、微多孔質フィルムを作製するに当たっては、予め各原材料を均一に分散するように特殊ミキサー等で攪拌・混合して原料混合物を作製しておくが、原料混合物を得る時点で、シリカ粉体の三次粒子(二次粒子の凝集体)をうまく砕いて二次粒子のレベルに分散させておくことを理想とし、できる限りこの状態に近づけるようにしている。尚、原料混合物の均一分散性が高いことは、微多孔質フィルム中の各原材料の均一分散性が高いことを意味し(但し、原料混合物を作製した後に溶融混練製膜過程でガラスフレークが砕かれやすい条件の場合を除く)、また、シリカ粉体の均一分散性が高いことは、ガラスフレークを含む各原材料の均一分散性も高いことを意味する(但し、原料混合物を作製した後に溶融混練製膜過程でガラスフレークが砕かれやすい条件の場合を除く)。
〈均一分散性(ガラスフレーク)〉
高分解能3DX線顕微鏡(リガク社製)を使い、微多孔質フィルムの面方向と垂直方向に断層画像をランダムに50個取得し、画像中に白く写るガラスフレーク(粒径10μm以上の一次粒子)の分散配置状態の度合いをチェックし、評価した。
〈向き・角度(ガラスフレーク)〉
高分解能3DX線顕微鏡(リガク社製)を使い、微多孔質フィルムの面方向と垂直方向に断層画像をランダムに複数個取得し、これを基に、画像中に白く写るガラスフレーク(一次粒子)の向き(角度)をランダムに50個チェックし(測定し)、評価した(平均値を求めた)。
〈ベース厚さ〉
ダイヤルゲージ(尾崎製作所社製 ピーコックG-6)を用いて、微多孔質フィルム(リブ状突起を有する場合はリブ状突起を含まない箇所)の任意の点、数箇所を測定した。
〈引張強度、伸び〉
微多孔質フィルムから、MDおよびCD方向に、10mm×70mmの長方形サイズに裁断し試験片とする。容量294N以下のショッパー式またはこれに準ずる引張試験機を用い、試験機のつかみの間隔(a)を約50mmとし、試験片を取り付け、毎分200mmの引張速さで引張試験を行い、試験片が切断した時の引張荷重(b)、距離(c)を読む。引張強度は、引張荷重(b)を試験片の断面積で除して算出する。伸びは、距離(c)を試験機のつかみの間隔(a)で除して算出する。
〈空隙率〉
微多孔質フィルムの細孔容積(水銀圧入法)と真密度(浸漬法)から、次式により算出した。
空隙率=Vp/((1/ρ)+Vp)
但し、Vp:細孔容積(cm3/g)、ρ:真密度(g/cm3)
〈平均細孔径〉
水銀圧入時の、圧力と水銀の容量から細孔径分布を算出した。全細孔容積の50%の容積の水銀が圧入された時点の細孔径を平均細孔径(メディアン径)とした。
〈最大孔径〉
平均細孔径試験における細孔径分布曲線から、水銀の圧入が開始された孔径を最大孔径とした。
〈浸透性〉
微多孔質フィルムを2cm×2cmの正方形サイズに裁断した試験片を、常温にて、水を注入したシャーレの水面に浮かべたのち、試験片全体に水が浸透し、試験片全体が半透明になるまでの時間を測定し、浸透性(秒)とした。
〈電気抵抗〉
微多孔質フィルムを70mm×70mmの正方形サイズに裁断して試験片とし、SBA S 0402に準拠した試験装置で測定した。
〈耐酸化寿命〉
50mm×50mmの正方形状の鉛板製の正極および負極を、70mm×70mmの正方形状に裁断した微多孔質フィルム製セパレータを挟んで、同心状にかつ正方形状の向きを合わせて積層し、積層した正極(1枚)、セパレータ(1枚)、負極(1枚)からなる極群に19.6kPaの加圧をかけて電槽内に組み込んだ後、比重1.300(20℃)の希硫酸電解液を1000ml注入し、液温度50±2℃で5.0Aの直流定電流を流し、端子電圧が2.6V以下または電圧差が0.2V以上となった時点の通電時間を測定し、耐酸化時間(h)とした。尚、表1および表2には、従来例の値を100とした場合の相対値を表示した。
〈デンドライトショート特性〉
70mm×70mmの正方形状にカットした微多孔質フィルムを50mm×50mmの正方形状の鉛極板(純鉛製、厚さ3mm)2枚で挟んで、微多孔質フィルムと2枚の鉛極板の3つの正方形の中心が一致しかつ3つの正方形の各辺が互いに平行であるようにして、電槽内に水平状態に設置し、その上に(正方形の中心位置に)5kgの重りを載せた後、飽和硫酸鉛水溶液を注入する。その後、鉛極板に3.2mAの電流を通電し、電圧の変化を連続的に記録する。電圧は、通電開始後にやや上昇し、その後緩やかに低下する。この時の最大電圧の70%に電圧が低下するまで時間を計測する。尚、表1および表2には、従来例の値を100とした場合の相対値を表示した。
(1)本発明の実施例1~12のセパレータは、従来例のセパレータに対し、MD方向の引張強度が49.7~58.5MPaと向上し、CD方向の引張強度が10.1~11.2MPaと同等以上、CD方向の伸びが610~650%と略同等、MD方向の伸びが40~52%とやや低下したが鉛蓄電池用セパレータとして問題のない水準を維持し、平均細孔径が0.09μmと同等を維持し、最大孔径が0.65μmと同等を維持したが、無数の微細孔と大きな表面積を有するシリカ微粉体の一部をガラスフレークに置換したことで、空隙率が53~60体積%とやや低下し、浸透性が21~26秒とやや低下し、電気抵抗が0.0010~0.0012Ω・100cm2/枚とやや高くなったが、シリカ微粉体の一部をガラスフレークに置換したことで鱗片状の無機物によるポリエチレン樹脂基材への効果的な補強効果が発揮されたことで、耐酸化寿命が110~150%と向上し、シリカ微粉体の一部を置換する形で平均粒径が50~600μmで平均厚さが0.5~6.0μmのガラスフレークを適当量添加し微多孔質フィルム中に平均粒径(粒径10μm以上の粒子)が40~150μmで平均厚さが0.5~6.0μmのガラスフレークを均一分散状態にかつその面方向が微多孔質フィルムの面方向に略配向するように適当量を配置するように含ませたことで、デンドライトショート特性が130~150%と改善した。よって、本発明の実施例1~12のセパレータを使って、充電制御車やアイドリングストップ車といった特殊な電池の使用環境(電池は満充電されることなく、常に充放電を繰り返し、放電気味の使用状態)となる自動車用鉛蓄電池に適用した場合に、デンドライトショートの発生を抑え、デンドライトショートの同時多発的な現象による早期の電池寿命を抑えることに寄与する。
(2)比較例1のセパレータは、原料組成物中および微多孔質フィルム中のガラスフレークの含有量がシリカ微粉体およびガラスフレークの合計含有量の1.0重量%と少なかったため、従来例のセパレータに対し、電気抵抗の悪化が避けられているが、デンドライトショート特性の改善が見られない。
(3)比較例2のセパレータは、原料組成物中および微多孔質フィルム中のガラスフレークの含有量がシリカ微粉体およびガラスフレークの合計含有量の20.0重量%と多かったため、従来例のセパレータに対し、デンドライトショート特性が150%と大幅な改善が見られるが、電気抵抗が0.0016Ω・100cm2/枚と大幅に悪化している。
(4)比較例3のセパレータは、原料組成物中のシランカップリング剤の含有量が3.5重量%と多かったため、従来例のセパレータに対し、浸透性が35秒と大幅に低下し、電気抵抗が0.0016Ω・100cm2/枚と大幅に悪化している。
(5)比較例4のセパレータは、原料組成物中および微多孔質フィルム中のガラスフレークの平均厚さが10.0μmと厚かったため、原料組成物中および微多孔質フィルム中のガラスフレークの含有量をシリカ微粉体およびガラスフレークの合計含有量の12.0重量%と多くしたが、従来例のセパレータに対し、デンドライトショート特性が110%の改善に留まっている。
(6)比較例5のセパレータは、原料組成物中のガラスフレークの平均粒径および微多孔質フィルム中のガラスレークの平均粒径(粒径10μm以上の粒子)が10μmと小さかったため、ガラスフレークの含有量をシリカ微粉体およびガラスフレークの合計含有量の15.0重量%と多くし、微多孔質フィルム中のガラスフレークの面方向と微多孔質フィルムの面方向が略同方向となる傾向がやや低下したものの、従来例のセパレータに対し、デンドライトショート特性が140%と改善が見られるが、電気抵抗が0.0016Ω・100cm2/枚と大幅に悪化している。
(7)比較例6のセパレータは、原料組成物中のガラスフレークの平均粒径が1000μmと大きく、微多孔質フィルム中のガラスフレークの平均粒径(粒径10μm以上の粒子)が180μmであったため、微多孔質フィルム中のガラスフレーク(粒径10μm以上の一次粒子)の均一分散性が低下し、従来例のセパレータに対し、デンドライトショート特性が110%の改善に留まっている。
Claims (6)
- ポリオレフィン系樹脂とシリカ粉体と可塑剤を主体とする原料組成物を溶融混練して製膜後前記可塑剤の一部または全部を除去してなる、ベース厚さが0.1~0.3mmで平均細孔径(水銀圧入法)が0.01~0.5μmで最大孔径(水銀圧入法)が0.3~1.0μmで空隙率(水銀圧入法)が50~90体積%である微多孔質フィルムよりなる鉛蓄電池用セパレータにおいて、
前記原料組成物には、更に、平均粒径が20~800μmで平均厚さが0.2~8μmの自己造膜性を有しないガラスフレークを前記シリカ粉体と前記ガラスフレークの合計含有量の2~15重量%と、シランカップリング剤(固形分)を0~3重量%含み、
前記微多孔質フィルムは、前記ポリオレフィン系樹脂と前記シリカ粉体と前記可塑剤と前記ガラスフレークの合計含有量が90重量%以上、前記ポリオレフィン系樹脂の含有量が20~60重量%、前記シリカ粉体の含有量が40~80重量%、前記可塑剤の含有量が0~30重量%、前記ガラスフレークの含有量が前記シリカ粉体と前記ガラスフレークの合計含有量の2~15重量%であり、
前記微多孔質フィルム中の前記ガラスフレークは、平均厚さが0.2~8μmであり、
前記微多孔質フィルム中の前記ガラスフレークの粒径10μm以上の粒子は、平均粒径が20μm以上であり、その面方向が前記微多孔質フィルムの面方向に略配向するように配置されており、
(前記微多孔質フィルム中の前記ガラスフレークの含有量(重量%))/(前記微多孔質フィルム中の前記ガラスフレークの平均厚さ(μm))の値が1以上であることを特徴とする鉛蓄電池用セパレータ。 - (前記微多孔質フィルム中の前記ガラスフレークの含有量(重量%))/(前記微多孔質フィルム中の前記ガラスフレークの平均厚さ(μm))の値が2以上であることを特徴とする請求項1に記載の鉛蓄電池用セパレータ。
- 前記微多孔質フィルム中の前記ガラスフレークの粒径10μm以上の粒子の80%以上が、その面方向が微多孔質フィルムの面方向に対して20゜以下に配向するように配置されていることを特徴とする請求項1または2に記載の鉛蓄電池用セパレータ。
- 前記原料組成物中の前記シランカップリング剤(固形分)の含有量が0.1重量%以上であることを特徴とする請求項1乃至3の何れか1項に記載の鉛蓄電池用セパレータ。
- 前記原料組成物中および前記微多孔質フィルム中の前記ガラスフレークの平均厚さが2μm以下であり、前記原料組成物中の前記ガラスフレークの含有量が前記シリカ粉体と前記ガラスフレークの合計含有量の2~8重量%であり、前記微多孔質フィルム中の前記ガラスフレークの含有量が前記シリカ粉体と前記ガラスフレークの合計含有量の2~8重量%であり、(前記微多孔質フィルム中の前記ガラスフレークの含有量(重量%))/(前記微多孔質フィルム中の前記ガラスフレークの平均厚さ(μm))の値が10以下であることを特徴とする請求項1乃至4の何れか1項に記載の鉛蓄電池用セパレータ。
- 請求項1乃至5の何れか1項に記載のセパレータを使用したことを特徴とする鉛蓄電池。
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EP15850420.9A EP3208868A4 (en) | 2014-10-15 | 2015-07-21 | Separator for lead-acid batteries, and lead-acid battery |
US15/516,487 US10270136B2 (en) | 2014-10-15 | 2015-07-21 | Separator for lead-acid battery, and lead-acid battery |
CN201580055743.1A CN106797007B (zh) | 2014-10-15 | 2015-07-21 | 铅蓄电池用隔板和铅蓄电池 |
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JP2021111491A (ja) * | 2020-01-08 | 2021-08-02 | 古河電池株式会社 | 液式鉛蓄電池 |
JP2021163615A (ja) * | 2020-03-31 | 2021-10-11 | 古河電池株式会社 | 鉛蓄電池 |
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WO2019124213A1 (ja) * | 2017-12-18 | 2019-06-27 | 日本碍子株式会社 | Ldhセパレータ及び亜鉛二次電池 |
CN112514152B (zh) * | 2018-08-10 | 2023-07-14 | 日本瑞翁株式会社 | 非水系二次电池粘接层用浆料组合物、粘接层、间隔件以及非水系二次电池 |
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