JP2008105402A - Metallized porous film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metallized porous film which has permeability in the whole sheet, and high elongation. <P>SOLUTION: The metallized porous film comprises a metal layer at least on one side of a porous film comprising a polyolefin-based resin, wherein the Gurley air permeability is in the range of 1-10,000 seconds/100 mL, the average pore diameter of a pore is in the range of 35-500 nm, and the degree of the elongation at break in a longitudinal direction of a film is in the range of 10-300%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention exhibits high elongation compared to a sheet having a conventional metal layer, and the entire sheet has permeability, so that it is suitable for a wide range of applications such as packaging applications, industrial applications, and building material applications. The present invention relates to a metallized porous film having a metal layer.

  The sheet | seat which has a metal layer on a porous base material is used for a reflecting plate, a battery separator, an electrode member, a freshness maintenance material, etc., for example, there exists an example as shown below.

  -Biaxially stretching a sheet composed of a polyolefin resin and a filler to form a sheet having holes by utilizing delamination between the polyolefin resin and the filler, and forming a metal layer on the sheet (Refer to patent document 1, for example).

  An electrical separator obtained by forming a porous electrically insulating ceramic coating on a fleece made of nonconductive polymer fibers (see, for example, Patent Document 2).

  A sheet having a hydrogen storage capacity obtained by coating the entire sheet having a hydrogen storage alloy fine powder layer on a woven or non-woven fabric with a porous metal plating layer (see, for example, Patent Document 3).

  A freshness-keeping member obtained by depositing silver on the polymer porous film (see, for example, Patent Document 4).

  An electrochemical detection element using a porous material made of a polymer or a polymer mixture (see, for example, Patent Document 5).

  A sheet material for an igniter having excellent reactivity by forming a metal layer on a porous oxidized polymer film and partially infiltrating the metal into the pores (see, for example, Patent Document 6).

  -A conductive sheet that forms a metal layer on a substrate having through holes formed by drilling with a needle or the like, and also provides conductivity on the front and back of the sheet by forming a metal layer in the holes (for example, patents) Reference 7).

  A method of forming different metal layers on the front and back of the breathable sheet (for example, see Patent Document 8).

  In addition, for example, the following methods are generally known so far as methods for producing a porous film containing polyolefin as a main component.

  The manufacturing method of the porous film which has polyolefin as a main component is generally divided roughly into a wet method and a dry method.

  As a wet method, an extractable is added to a polyolefin, finely dispersed, formed into a sheet, and then the extractable is extracted with a solvent or the like to form pores, and stretched before and / or after extraction as necessary. There are extraction methods including processes (see, for example, Patent Documents 9 and 10).

As a dry method, an unstretched sheet in which a special crystalline lamella structure is formed by producing a special melt crystallization condition of low temperature extrusion and high draft at the time of forming into a sheet by melt extrusion is mainly stretched uniaxially. There is a lamellar stretching method in which a lamellar interface is cleaved to form a hole (for example, see Patent Document 11 and Non-Patent Document 1). As another dry method, there is an inorganic particle method in which pores are formed by peeling an interface between different materials by stretching an unstretched sheet obtained by adding a large amount of incompatible particles such as inorganic particles to polyolefin (see, for example, Patent Documents). 12, 13). In addition, a β crystal having a low crystal density (crystal density: 0.922 g / cm ³ ) is formed at the time of preparing an unstretched sheet by melt extrusion of polypropylene, and an α crystal having a high crystal density (crystal density: There is a β crystal method in which crystal transition is performed to 0.936 g / cm ³ ) and pores are formed by a difference in crystal density between the two (see, for example, Patent Documents 14 and 15 and Non-Patent Document 2).

In the β crystal method, in order to form a large amount of pores in the stretched film, it is necessary to selectively generate a large amount of β crystal in the unstretched sheet before stretching. For this reason, in the β crystal method, it is important to use a β crystal nucleating agent and to generate β crystals under specific melt crystallization conditions. In recent years, materials having higher β-crystal-forming ability have been proposed as a β-crystal nucleating agent compared to quinacridone compounds (for example, see Non-patent Document 3) that have been used for a long time (for example, patents). References 16 to 18) and porous films mainly composed of various polypropylenes have been proposed.
Japanese Patent Laid-Open No. 2004-341068 JP-T-2006-504228 JP-A-2005-280164 JP 2003-47399 A Japanese National Patent Publication No. 11-503826 JP-A-6-172077 Japanese Patent No. 2668234 Japanese Patent No. 3146553 Japanese Patent No. 1299979 (Claim 1) Japanese Patent No. 3258737 (Claim 1, page 3, second paragraph, lines 8-20) Japanese Patent No. 1046436 (Claim 1) Japanese Patent No. 1638935 (Claims 1 to 7) JP-A-60-129240 (Claims 1 to 4) Japanese Patent No. 25009030 (Claims 1 to 8) Japanese Patent No. 3443934 (claims 1-5) Japanese Patent No. 2055797 (Claims 1 to 8) Japanese Patent No. 3243835 (Claim 1) Japanese Patent No. 3374419 (Claims 1 to 4) Adachi et al., “Chemical Industry”, 47, 1997, p. 47-52 M. Xu et al., “Polymers for Advanced Technologies”, Vol. 7, 1996, p. 743-748 Fujiyama, “Polymer Processing”, Volume 38, 1989, p. 35-41

  Conventional sheets having a metal layer on a porous substrate may lose the permeability of the entire sheet by forming a metal layer on the sheet even if the porous substrate itself has permeability. Many. Moreover, even if the entire metallized sheet has permeability, only the sheet having a low elongation of the entire sheet exists because the elongation of the porous base material is low.

  That is, until now, there has been no metallized porous sheet that is permeable to the entire sheet and has a high elongation.

  Conventionally, deposition onto a film having a high melting point such as an oxidized polymer film has been easy, but metal is directly deposited on a resin film having a low melting point, such as a film containing polyolefin as a main component, while maintaining permeability. That was difficult.

  The object of the present invention is to solve the above problems. That is, an object of the present invention is to provide a metallized porous film that is permeable to the entire sheet, has high elongation, and has a metal layer.

  The present inventors have found that the above problem can be solved mainly by the following configuration.

  (1) A metallized porous film having a metal layer on at least one surface of a porous film containing a polyolefin-based resin, wherein the Gurley permeability is in the range of 1 to 10,000 seconds / 100 ml, and the average pore diameter of the pores Is a metallized porous film having a range of 35 to 500 nm and a breaking elongation in the longitudinal direction of the film of 10 to 300%.

  (2) The metallized porous film according to (1), wherein the porous film is oriented at least uniaxially.

  (3) The metallized porous film according to the above (1) or (2), wherein the porosity is 20 to 85%.

  (4) The metallized porous film according to any one of (1) to (3), wherein the polyolefin-based resin is polypropylene.

  (5) The metallized porous film according to (4), wherein the porous film has β crystal activity.

  (6) The metallized porous film according to any one of (1) to (5), wherein the glossiness of the metal layer is 100 to 700%.

  (7) The metallized porous film according to any one of the above (1) to (6), wherein the surface resistivity of the metal layer is 0.1 to 100Ω / □.

  Since the metallized porous film of the present invention has high elongation compared to a porous sheet having a conventional metal layer, it is suitable for applications that require durability, and is excellent in handling properties and durability. , Productivity and workability are improved. In addition, because the entire sheet is permeable and moisture-permeable and waterproof, it exhibits excellent properties in various fields such as packaging materials, construction materials, and building materials, such as separators for batteries and electrolytic capacitors, and electrode member applications. .

  In addition, the metalized porous film of the present invention does not require such a process as compared to a sheet composed of a base material and a metal layer having permeability using physical perforation by human power or machine. Excellent productivity.

  Further, compared to a metallized sheet using a physically perforated substrate, the metallized porous film of the present invention has extremely small holes, so that, for example, it allows vapor to pass but not water (moisture permeable and waterproof). Selective permeability. Furthermore, since it has many uniform and dense holes, it has excellent permeability.

  First, the porous film will be described.

  A porous film is used for the base material of the metallized porous film of the present invention in order to impart excellent permeability to the metallized porous film of the present invention.

  The porous film has fine pores having a porosity of 10% or more in the film, and is connected so as to connect the front and back of the film, thereby imparting permeability.

  In the present invention, a porous film containing a polyolefin-based resin is used. Preferably, a porous film composed mainly of polyolefin is used. When the film contains a polyolefin resin as a main component, the film is excellent in terms of heat resistance, moldability, production cost reduction, chemical resistance, oxidation resistance, reduction resistance, and the like.

  Examples of the monomer component constituting the polyolefin resin include ethylene, propylene, 1-butene, 1-pentene, 3-methylpentene-1, 3-methyl-1-butene, 1-hexene and 4-methyl. -1-pentene, 5-ethyl-1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-eicosene, vinyl And cyclohexene, styrene, allylbenzene, cyclopentene, norbornene, 5-methyl-2-norbornene, and the like. These homopolymers and at least two kinds of copolymers selected from the above monomer components, Examples include, but are not limited to, blends of copolymers and copolymers. In addition to the above monomer components, for example, vinyl alcohol, maleic anhydride or the like may be copolymerized or graft polymerized, but is not limited thereto.

  The porous film in the present invention preferably contains a polyolefin resin as a main component. In the present invention, this (referred to as a main component) is defined as including 80% by weight or more of polyolefin monomer with respect to the total amount of monomers of all the polymers constituting the film. When the content of the polyolefin monomer is less than the above range, heat resistance, chemical resistance and oxidation / reduction resistance tend to decrease. The content of the polyolefin monomer is more preferably 85% by weight or more, and still more preferably 90% by weight or more, based on the total amount of monomers of all polymers constituting the film.

  The resin constituting the porous film used in the present invention includes a flame retardant, a heat stabilizer, a weathering material, an antioxidant, an ultraviolet absorber, a light stabilizer, a rust inhibitor, and a copper damage stable depending on the purpose. Various additives such as additives, antistatic agents, pigments, plasticizers, endblockers, lubricants, organic lubricants, chlorine scavengers, antiblocking agents, viscosity modifiers, and the like are added within a range that does not impair the purpose of these inventions. It doesn't matter.

  Among these, selection of the kind and addition amount of the antioxidant and the heat stabilizer is important for the long-term heat resistance of the film. When the porous film in these inventions is made of polypropylene, examples of the antioxidant and heat stabilizer that are preferably added include various compounds.

Examples of the antioxidant include 2,6-di-tert-butyl-p-cresol (BHT); 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a. , A ′, a ″-(mesitylene-2,4,6-triyl) tri-p-cresol (for example, IRGANOX 1330 manufactured by Ciba Specialty Chemicals);
Examples include pentaerythrole tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (for example, IRGANOX 1010 manufactured by Ciba Specialty Chemicals Co., Ltd.).

Examples of the heat stabilizer include tris (2,4-di-tert-butylphenyl) phosphite (for example, IRGAFOS168 manufactured by Ciba Specialty Chemicals);
Examples include a reaction product of 3-hydroxy-5,7-di-tert-butyl-furan-2-one and o-xylene (for example, HP-136 manufactured by Ciba Specialty Chemicals Co., Ltd.).

  However, it is not limited to the antioxidants and heat stabilizers exemplified above. These antioxidants and heat stabilizers are preferably used in combination of two or more, and the content thereof is 0.03 to 1% by weight with respect to the total amount of polypropylene in the film when polypropylene is used as the olefin. It is preferable. When the content of each of the antioxidant and the heat stabilizer is less than the above range, the long-term heat resistance may be inferior in the manufacturing process until the porous film is obtained from the initial raw material and the subsequent secondary processing process. Moreover, when content of each antioxidant and a heat stabilizer exceeds the said range, even if it adds more, the long-term heat resistance of the porous film obtained will not improve, and it may be inferior to economical efficiency. The content of each of the antioxidant and the heat stabilizer is more preferably 0.05 to 0.9% by weight, still more preferably 0.1 to 0.8% by weight, based on the total amount of polypropylene in the film. .

  The porous film in the present invention is preferably composed mainly of polypropylene. A film mainly composed of polypropylene can be produced at low cost because it can be continuously formed by using a conventional melt film forming method and productivity can be improved. Further, a metallized porous film using a porous film mainly composed of polypropylene is excellent in heat resistance, moldability, chemical resistance, oxidation / reduction resistance, and the like. Furthermore, by using polypropylene as a main component, a β crystal method excellent in productivity and quality balance can be used.

  Hereinafter, preferred embodiments for achieving high porosity, permeability, strength, and elongation when the above-described porous film of the present invention is mainly composed of polypropylene will be described.

  Polypropylene in the present invention is mainly composed of a homopolymer of propylene, but within a range not impairing the purpose of these inventions, improved film-forming properties, improved workability, promotion of pore formation, improved adhesion to metal layers, etc. Depending on various purposes, a polymer obtained by copolymerization of propylene and a monomer other than propylene may be used, or other polyolefin may be blended with polypropylene. Examples of monomers constituting such copolymer components and blends include, for example, ethylene, 1-butene, 1-pentene, 3-methylpentene-1, 3-methylbutene-1, 1-hexene, and 4-methylpentene. -1,5-ethylhexene-1,1-octene, 1-decene, 1-dodecene, vinylcyclohexene, styrene, allylbenzene, cyclopentene, norbornene, 5-methyl-2-norbornene, and derivatives thereof. However, it is not limited to these.

  When the porous film in the present invention contains polypropylene as a main component, it is preferable that 90% by weight or more of a propylene monomer is included with respect to the total amount of monomers of all the polymers constituting the film. When the content of the propylene monomer is less than the above range, heat resistance, chemical resistance, oxidation resistance / reduction resistance may be lowered, and when the β crystal method is used, the β crystal activity of the resulting porous film is As a result, the porosity may be low or the transmission performance may be poor. The content of the propylene monomer is more preferably 95% by weight or more, and still more preferably 97% by weight or more based on the total amount of monomers of all polymers constituting the film.

  When polypropylene is the main component, high melt tension polypropylene (HMS-PP) is included in order to achieve high film forming properties, high porosity, permeability, and strength by high magnification stretching. Is preferred.

  In general, the method for obtaining HMS-PP is not particularly limited, but the following methods are exemplified, and these methods are preferably used.

  A method of blending polypropylene containing a large amount of high molecular weight components.

  -A method of blending oligomers and polymers having a branched structure.

  A method for introducing a long chain branched structure into a polypropylene molecule as described in JP-A-62-1121704.

  -As described in Japanese Patent No. 2869606, melt tension and intrinsic viscosity, crystallization temperature and melting point satisfy specific relationships without introducing long chain branching, and boiling xylene extraction residual ratio is specific. A method for producing a linear crystalline polypropylene in the range.

  Among these polypropylenes, HMS-PP used in the present invention is preferably a polypropylene having a long-chain branch in the main chain skeleton because the stability of melt extrusion and the above-described effects of addition may be large. .

  Here, the polypropylene having a long chain branch in the main chain skeleton is a polypropylene having a polypropylene chain branched from the polypropylene main chain skeleton.

  Specific examples of the polypropylene having a long chain branch in the main chain skeleton include polypropylene manufactured by Basell (type names: PF-814, PF-633, PF-611, SD-632, etc.), and polypropylene manufactured by Borealis (type name: WB130HMS) and Dow polypropylene (type names: D114, D201, D206, etc.).

  The amount of HMS-PP used in the present invention is not particularly limited, but is preferably 0.1 to 50% by weight based on the total amount of polypropylene in the film. When the mixing amount is less than the above range, the film formability, particularly in the case of longitudinal and transverse sequential biaxial stretching, the transverse stretchability particularly when stretched at a high magnification in the longitudinal direction is lowered (lateral stretching step). May break the film). In addition, the porosity may be low or the permeability may be poor. Exceeding the above range, in the case of film-formability, longitudinal / horizontal sequential biaxial stretching, the stretchability in the longitudinal direction particularly when stretched at a high magnification in the longitudinal direction is lowered (the film is cut in the longitudinal stretching step). There is a case. Moreover, the stable discharge property of the molten polymer at the time of melt extrusion and the impact resistance of the film may be lowered. Furthermore, the β crystal fraction defined below may decrease more than necessary. The mixing amount of HMS-PP is more preferably 0.5 to 20% by weight, most preferably 0.5 to 5% by weight, based on the total amount of polypropylene in the film.

  When the porous film in the present invention contains polypropylene as a main component, the melt flow rate (MFR) of the polypropylene is preferably 1 to 30 g / 10 min from the viewpoint of film forming properties. When the MFR is less than the above range, melt extrusion at low temperature becomes unstable, it takes a long time to replace the extrusion raw material, and it becomes difficult to form a film having a uniform thickness. May cause problems such as deterioration. When the MFR exceeds the above range, the landing point of the molten polymer on the metal drum greatly fluctuates when the molten polymer discharged from the slit-shaped die in the casting step is cast into a metal drum and formed into a sheet shape. When the β crystal method is used, defects such as undulations occur in the sheet, and it becomes difficult to generate uniform β crystals in the unstretched sheet. In some cases, the unevenness of the formation becomes large. MFR is more preferably 1 to 20 g / 10 min.

  When the porous film in the present invention contains polypropylene as a main component, it has one or more polymers selected from polyolefin resins other than polypropylene, which have high affinity with polypropylene from the viewpoint of assisting pore formation. It doesn't matter. Examples of the polyolefin resin include, but are not limited to, homopolymers or copolymers composed of olefins other than propylene such as the monomers exemplified above. As the polyolefin-based resin, it is finely dispersed in polypropylene in the melt extrusion process, the film forming property is improved in the subsequent stretching process, the pore formation is promoted, and the obtained porous film is excellent in permeability. Since there is a case, ultra low density polyethylene (mVLDPE) by a metallocene catalyst method is mentioned, but it is not necessarily limited to this. Specific examples of the mVLDPE include “Engage” (type name: 8411, etc.) manufactured by DuPont Dow Elastomers.

  The porous film in the present invention preferably has β crystal activity. Since the porous film of the present invention has β crystal activity, pore formation using the β crystal method can be performed. When polypropylene is used for the porous film, having β crystal activity makes it possible to produce β crystals in the unstretched sheet in the manufacturing process, and crystallizes β crystals into α crystals in the subsequent stretching process. The pores can be formed by the transition and the difference in crystal density. By forming the holes using the β crystal method, uniform and dense holes can be obtained, which is preferable. Further, the reflectance of light can be increased. Moreover, since the extraction method using a solvent and the physical perforation method are not used, it is excellent from the viewpoints of productivity and environmental load, and the resulting porous film has excellent permeability.

  Here, “having β crystal activity” means using a differential scanning calorimeter (DSC), a sample of 5 mg in a nitrogen atmosphere in accordance with JIS K 7122 (1987) at a rate of 10 ° C./min at 280 ° C. To a heat curve obtained when the temperature is raised again at a rate of 10 ° C./min. The peak of the endothermic peak accompanying the melting of the β crystal is present, and the heat of fusion calculated from the peak area of the endothermic peak is 10 mJ / mg or more. In addition, hereinafter, the calorific curve obtained by the first temperature increase may be referred to as a first run caloric curve, and the caloric curve obtained by the second temperature increase may be referred to as a second run caloric curve. Here, Cho et al., “Polymer”, 44, p. 4053-4059 (2003); Takahashi et al., “Molding”, 15, p. As disclosed in 756-762 (2003) and the like, the ability to form β crystals of polypropylene can be confirmed using DSC. In these documents, a calorimetric curve is collected using DSC under temperature conditions close to the present invention, and the β crystal activity of polypropylene containing a β crystal nucleating agent is confirmed. Here, “having β-crystal activity” means that a β-crystal can be generated when polypropylene is crystallized. In addition, the determination of the β crystal activity here is performed on the film after the extrusion, casting, stretching, and winding processes, that is, after film formation. Therefore, when the polypropylene of the film contains a β crystal nucleating agent as exemplified below, the β crystal activity is determined for the entire film containing the β crystal nucleating agent.

In addition, when there is an endothermic peak in the above temperature range but it is unclear whether it is due to melting of the β crystal, the sample is combined with the DSC result under the specific conditions described in the detailed description of the measurement method below. The sample that has been melt crystallized may be determined as “having β-crystal activity” by the following K value calculated using the wide-angle X-ray diffraction method. That is, it is observed around 2θ = 16 °, and is observed at (300) plane diffraction peak intensity (referred to as Hβ ₁ ) due to β crystal and near 2θ = 14, 17, 19 °, respectively, due to α crystal. From the diffraction peak intensities of the (110), (040), and (130) planes (respectively Hα ₁ , Hα ₂ , and Hα ₃ ), the K value calculated by the following formula is 0.3 or more, and more preferably May be determined to be “having β-crystal activity” by being 0.5 or more. Here, the K value is an empirical value indicating the ratio of β crystals. For details of the K value such as the calculation method of each diffraction peak intensity, refer to A. Turner Jones et al., “Macromoleculare Chemie”, 75, pages 134-158 (1964). Good.

K = Hβ ₁ / {Hβ ₁ + (Hα ₁ + Hα ₂ + Hα ₃ )}
(However, Hβ ₁ : (300) plane diffraction peak intensity attributed to polypropylene β crystal, Hα ₁ , Hα ₂ , Hα ₃ : (110), (040), (130 attributed to polypropylene α crystal, respectively. ) Diffraction peak intensity of surface)
Here, when the porous film in the present invention is mainly composed of polypropylene, in order to form a more uniform and many pores, the β film fraction of these porous films is about the porous film in the present invention. It is preferable that it is 30% or more. In addition, the β crystal fraction is the same as that of the polypropylene-derived β crystal whose apex is observed at 140 ° C. or higher and lower than 160 ° C. in the second run caloric curve obtained by the second temperature increase using DSC. The amount of heat of fusion (ΔHβ; symbol 2 in FIG. 2 which is the same calorimetric curve as FIG. 1) calculated from the peak area of the endothermic peak (one or more peaks) accompanying melting, and the apex observed at 160 ° C. or higher The heat of fusion calculated from the peak area of the endothermic peak accompanying the melting of the crystal derived from the polypropylene other than the β crystal having a peak exceeding the base line accompanying the melting of the crystal derived from the polypropylene other than the crystal (ΔHα; the same heat quantity as FIG. 1) It calculates | requires using the following formula from the code | symbol 3) of FIG. 2 which is a curve. Here, the β crystal fraction is the ratio of β crystals to all the crystals of polypropylene. In Japanese Patent Application Laid-Open No. 2004-142321 and Japanese Patent Application Laid-Open No. 2004-160689, the temperature condition close to that of the present invention is used. The DSC is used to measure the calorimetric curve to determine the β crystal fraction of the film. In addition, although the endothermic peak which has a vertex in 140-160 degreeC exists, when it is uncertain whether it originates in melt | dissolution of (beta) crystal | crystallization, what is necessary is just to determine with the said K value.

β crystal fraction (%) = {ΔHβ / (ΔHβ + ΔHα)} × 100
If the β crystal fraction is less than 30%, the resulting porous film may have a low porosity or poor permeability. The β crystal fraction is more preferably 40% to 90%, further preferably 45% to 80%, and most preferably 50% to 70%.

In order to impart such a high β crystal activity, it is preferable that a so-called β crystal nucleating agent is added to the porous film in the present invention. When such a β crystal nucleating agent is not added, the above high β crystal fraction may not be obtained. Examples of the β crystal nucleating agent that can be preferably added to the polypropylene constituting the porous film mainly composed of the polypropylene of the present invention include nanoscale iron oxide (FeO), potassium 1,2-hydroxystearate, benzoic acid, and the like. Alkali or alkaline earth metal salts of carboxylic acids typified by magnesium oxide, magnesium succinate, magnesium phthalate, etc .; Amide compounds typified by N, N′-dicyclohexyl-2,6-naphthalenedicarboxamide; benzene Aromatic sulfonic acid compounds typified by sodium sulfonate, sodium naphthalene sulfonate, etc .; di- or triesters of dibasic or tribasic carboxylic acids; tetraoxaspiro compounds; imide carboxylic acid derivatives; phthalocyanine blue, etc. Phthalocyani Quinacridone pigments typified by quinacridone, quinacridonequinone, etc .; two components comprising component A which is an organic dibasic acid and component B which is an oxide, hydroxide or salt of a Group IIA metal of the periodic table Examples thereof include, but are not limited to. Moreover, only 1 type may be used and 2 or more types may be mixed and used. Among the above, the β crystal nucleating agent added to the polypropylene of the porous polypropylene film of the present invention is represented by the following chemical formula, and is represented by N, N′-dicyclohexyl-2,6-naphthalenedicarboxamide and the like. Amide compounds,
^{R 2 -NHCO-R 1 -CONH-} R 3
[Wherein R ¹ represents a saturated or unsaturated aliphatic dicarboxylic acid residue having 1 to 24 carbon atoms, a saturated or unsaturated alicyclic dicarboxylic acid residue having 4 to 28 carbon atoms, or a carbon number. Represents an aromatic dicarboxylic acid residue having 6 to 28, and R ² and R ³ are the same or different cycloalkyl groups having 3 to 18 carbon atoms, cycloalkenyl groups having 3 to 12 carbon atoms, or derivatives thereof. ];
A compound having the chemical formula:
R ⁵ —CONH—R ⁴ —NHCO—R ⁶
[Wherein R ⁴ represents a saturated or unsaturated aliphatic diamine residue having 1 to 24 carbon atoms, a saturated or unsaturated alicyclic diamine residue having 4 to 28 carbon atoms, or 6 to 6 carbon atoms. 12 heterocyclic diamine residues or aromatic diamine residues having ⁶ to 28 carbon atoms, wherein R ⁵ and R ⁶ are the same or different cycloalkyl groups having 3 to 12 carbon atoms and cycloalkenyl groups having 3 to 12 carbon atoms. A group or a derivative thereof. ];
A binary compound comprising a component which is an organic dibasic acid and a component which is an oxide, hydroxide or salt of a Group IIA metal of the periodic table;
Is particularly preferable because the specific gravity of the resulting porous film can be lowered (the porosity can be increased) and the air permeability can be improved.

  Specific examples of such particularly preferred β crystal nucleating agent or β crystal nucleating agent-added polypropylene include β crystal nucleating agent “NJESTER” (type name: NU-100, etc.) manufactured by Shin Nippon Rika Co., Ltd., and β crystal nuclei manufactured by SUNOCO. An additive-added polypropylene “BEPOL” (type name: B022-SP etc.) and the like can be mentioned.

  The addition amount of the β crystal nucleating agent is preferably 0.001 to 1% by weight based on the total amount of polypropylene in the film, although it depends on the β crystal forming ability of the β crystal nucleating agent to be used. If the amount of β-crystal nucleating agent is less than the above range, the resulting porous film may have insufficient β-crystal activity, high specific gravity (low porosity), or poor permeation performance. is there. If the amount of β-crystal nucleating agent exceeds the above range, the β-crystal fraction of the resulting porous film will not improve even if it is added more, the economy will be inferior, and the dispersibility of the nucleating agent itself will deteriorate. Conversely, the β crystal activity may decrease. The addition amount of the β crystal nucleating agent is more preferably 0.005 to 0.5% by weight, still more preferably 0.05 to 0.2% by weight.

  The porous film in the present invention has pores, and these pores are preferably substantially nucleus-free pores. Here, “nuclear-free pores” in the present invention are defined as pores in which nuclei for pore formation represented by resin, particles, etc. that induce pore formation by stretching or the like are not observed inside. The Such a non-nucleated hole is not observed inside the hole when an ultra-thin section of the film is observed under a specific condition using a transmission electron microscope (TEM) as described below. On the other hand, in the present invention, in a hole that does not correspond to a non-nucleated hole in the present invention, a nucleus having a spherical shape, a fibrous shape, an indefinite shape, or other shape is observed inside the hole in the TEM observation image. In the present invention, “having non-nuclear pores” means that the ratio (R) of the area of all nuclei in the total observation visual field area (total area of the film) in the TEM observation image is as shown in the following measurement method. It is defined as the case of 3% or less, and in this case, the porous film has non-nuclear holes. At this time, even a hole having a nucleus may be detected as a non-nucleated hole by the above method, but if the ratio R calculated by this method is in the above range, the object of the present invention is achieved. It is.

  When the porous film in the present invention has non-nucleated holes, there is a case where a uniform and dense hole structure can be formed because it does not depend on the formation of holes using the nuclei. Moreover, there is no coarse void formed from the nucleus, and the film may be difficult to cleave. Here, the cleaving of the film refers to a phenomenon in which the film is split into a plurality of sheets approximately parallel to the surface. Furthermore, when the porous film is subjected to secondary processing by having a nucleus-free pore, impurities may not fall off and / or dissolve in the next process, and the process may not be soiled. Thus, in order for a film to have a nucleus-free pore, it is important not to add a different polymer or particle having a low compatibility or affinity with the main polymer constituting the film as much as possible. R described above is more preferably 2% or less, and further preferably 1% or less.

  The thickness of the porous film in the present invention is preferably 5 to 200 μm. When the thickness is less than the above range, in the film production process or the subsequent metallization process, the film may be inferior in handling properties such as stretching or wrinkling. If the thickness exceeds the above range, the permeability may decrease and the productivity may also decrease. The thickness of the porous film of the present invention is more preferably 7 to 40 μm, further preferably 8 to 35 μm, and most preferably 9 to 30 μm.

  The method for obtaining a porous film having excellent permeability in the present invention is not particularly limited. For example, the wet method and the dry method as described above are disclosed, and these methods are preferably used.

  The porous film according to the present invention is preferably oriented at least in a uniaxial direction. By being oriented in at least a uniaxial direction, the strength of the film can be increased.

  Furthermore, if the film can be stretched and oriented in the flow direction, the film production speed (= line speed) can be increased even if the casting speed is the same in the production process, so that the film production area per unit time can be increased. it can. That is, the cost per unit area can be reduced. Further, when stretching / orienting in at least one direction, the formation of pores is promoted, so that the permeability can be remarkably improved.

  In the present invention, the porous film is more preferably biaxially oriented. When the film is biaxially oriented, it can be made into a film excellent in strength balance in each direction. When the film is biaxially oriented, toughness can be imparted to the film, and the film can be made difficult to tear in any direction. Thereby, the metallized porous film of the present invention can prevent the film from being excessively shrunk or torn in the lateral direction in the secondary processing step.

  For the production of a biaxially oriented film, for example, various film forming methods represented by various biaxial stretching methods such as simultaneous biaxial stretching, sequential biaxial stretching, and subsequent re-stretching are used. In order to achieve a high level of the object of the present invention to produce a metallized porous film with a high balance of directional elongation and high permeability, a longitudinal-transverse sequential biaxial stretching method is used. It is preferable. Compared with other manufacturing methods, the longitudinal-transverse sequential biaxial stretching method is also preferable from the viewpoint of the expandability of the apparatus.

  Below, an example of the manufacturing method of the porous film in this invention at the time of using the vertical-horizontal sequential biaxial stretching method, using polypropylene as a main component and using the β crystal method is shown.

  For example, after preparing a polypropylene containing HMS-PP and having a β-crystal nucleating agent added (having β-crystal activity), this is supplied to an extruder and melted at a temperature of 200 to 320 ° C., and after passing through a filter. Then, the sheet is extruded from a slit-shaped base, cast on a cooling metal drum, and cooled and solidified into a sheet to obtain an unstretched sheet. At this time, a polymer other than the above-described polypropylene may be appropriately added to the prepared polypropylene.

  Here, in order to generate a large amount of β crystals in the unstretched sheet, the melt extrusion temperature is preferably low, but if it is less than the above range, unmelted matter is generated in the molten polymer discharged from the die, and If it exceeds the above range, the thermal decomposition of polypropylene becomes severe, and film properties of the resulting porous film, such as Young's modulus, breaking strength, etc. May be inferior.

  Moreover, the temperature of the metal drum for cooling (cast drum) is set to 60 to 130 ° C., the film is crystallized under moderately slow cooling conditions, and β crystals are produced in large quantities and uniformly. In order to make a permeable porous film, the higher one is preferable. If the temperature of the cooling drum is lower than the above range, the β crystal fraction of the first run of the obtained unstretched sheet may be reduced. If the temperature exceeds the above range, solidification of the sheet on the drum becomes insufficient. , It may be difficult to uniformly peel the sheet from the drum. Further, the permeability of the obtained porous film tends to be higher as it approaches the upper limit in the temperature range described above, and tends to be lower as it approaches the lower limit, depending on the amount of β crystal in the obtained unstretched sheet. Presumed. Here, the amount of β crystals in the unstretched sheet corresponds to the β crystal fraction obtained from the calorific curve of the first run obtained by using the unstretched sheet as a sample and using DSC. In the case of a porous film having high permeability, the cast drum temperature is preferably 100 to 125 ° C.

  At this time, it is preferable that the time during which the unstretched sheet comes into contact with the drum (hereinafter, simply referred to as contact time with the drum) is 6 to 60 seconds. Here, the contact time with the drum is the time required until the unstretched sheet peels from the drum, with the start time (= 0 seconds) when the molten polymer first lands on the drum in the casting step. Means. In addition, when the casting process is composed of a plurality of drums, the total time when the unstretched sheet comes into contact with these drums is the contact time with the metal drum. If the contact time to the metal drum is less than the above range, although depending on the temperature, the unstretched sheet sticks at the time of peeling, or there are few β crystals generated in the unstretched sheet (the β crystal fraction of the unstretched sheet) Therefore, the porosity of the film after biaxial stretching may be lowered to an insufficient level. When the contact time with the metal drum exceeds the above range, although depending on the size of the metal drum, the peripheral speed of the metal drum may be lower than necessary and productivity may be reduced. Usually, the contact time of 10 minutes or more may not be substantially removed. The contact time with the metal drum is more preferably 7 to 45 seconds, and further preferably 8 to 40 seconds.

  In addition, as a method for closely contacting the cooling drum, any method among an electrostatic application (pinning) method, a contact method using the surface tension of water, an air knife method, a press roll method, an underwater casting method, and the like may be used. However, as a method for obtaining the porous film of the present invention, it is preferable to use an air knife method or an electrostatic application method that has good thickness controllability and can control the cooling rate by the temperature of the blowing air. Here, in the air knife method, air is blown from the non-drum surface, and the temperature is preferably 10 to 200 ° C. The surface β crystal amount is controlled by controlling the surface cooling rate, and the surface The porosity can be controlled, that is, the permeability of the resulting porous film can be controlled.

  Moreover, in the case of forming a laminate in which the second and third layers are coextruded and laminated on at least one side of the porous film, each of the above-described polypropylene is prepared with a desired resin as necessary. The resin is supplied to separate extruders, melted at the desired temperature, passed through a filtration filter, merged in a short tube or die, extruded from the slit die at the desired thickness of each layer, and then put into a cooling drum. It can be cast and allowed to cool and solidify into a sheet to form an unlaminated stretched sheet.

  Next, the obtained unstretched (laminated) sheet is biaxially stretched using a known general-purpose longitudinal-transverse sequential biaxial stretching method. First, an unstretched film is preheated by passing it through a roll maintained at a predetermined temperature, and subsequently, the film is maintained at a predetermined temperature and passed between rolls having a difference in peripheral speed, stretched in the longitudinal direction and immediately cooled.

  Here, in order to highly balance the porosity and the strength in the machine direction and to manufacture a porous film having high permeability, the stretch ratio in the machine direction is a point. The effective stretch ratio in the longitudinal direction when a porous polypropylene film is formed by a normal longitudinal-lateral sequential biaxial stretching method is in the range of 3 to 4.5 times, and if it exceeds 5 times, a stable film formation is obtained. Whereas it becomes difficult and the film is torn by transverse stretching, in the case of the porous film of the present invention, when making a porous film with higher porosity and permeability, the effective stretching ratio in the longitudinal direction Is preferably 5 to 10 times. Under the present circumstances, it is preferable that the porous film in this invention contains the above-mentioned HMS-PP, and this may enable the stable high magnification stretching in the longitudinal direction. If the effective stretching ratio in the machine direction is less than the above range, the porosity of the resulting porous film may be low and the permeability may be inferior. The film forming speed (= line speed) even at the same casting speed because the ratio is low. ) Is slow and productivity may be inferior. When the effective stretching ratio in the machine direction exceeds the above range, film breakage may occur sporadically by longitudinal stretching or transverse stretching, and film forming properties may be deteriorated. The effective stretch ratio in the machine direction is more preferably 5 to 9 times, still more preferably 5 to 8 times. In this case, it is preferable to perform the longitudinal stretching in at least two stages from the viewpoints of increasing porosity, improving permeation performance, suppressing surface defects, and the like. The longitudinal stretching temperature is preferably from 95 to 120 ° C., for example, from the viewpoints of stable film-forming properties, suppression of thickness unevenness, improvement of porosity and permeability, and the like. In the cooling process after longitudinal stretching, it is preferable from the viewpoint of dimensional stability in the longitudinal direction to give relaxation in the longitudinal direction to such an extent that the thickness unevenness and permeability of the film do not deteriorate. Furthermore, a desired resin layer may be appropriately placed on the film after longitudinal stretching by extrusion lamination or coating.

  Subsequently, the longitudinally stretched film is guided to a tenter type stretching machine, preheated at a predetermined temperature, and stretched in the transverse direction. Here, the effective stretching ratio in the transverse direction is preferably 12 times or less. If the effective stretching ratio in the transverse direction exceeds 12 times, the film forming property may be deteriorated. The transverse stretching temperature is preferably 100 to 150 ° C., for example, from the viewpoints of stable film-forming properties, suppression of thickness unevenness, improvement of porosity and permeability, and the like.

  After stretching in the transverse direction, from the viewpoint of improving the dimensional stability of the resulting porous film, the film is further heat-set at 100 to 180 ° C. while being relaxed by 1% or more in the transverse direction and cooled. Further, if necessary, at least one surface of the film is subjected to corona discharge treatment in air, nitrogen, or a mixed atmosphere of carbon dioxide and nitrogen. Subsequently, the porous film which has a polypropylene as a main component in this invention is obtained by winding up this film.

  Next, the metal layer will be described.

  The metallized porous film of the present invention has a configuration in which a metal layer is provided on at least one surface of the porous film.

  By providing a metal layer on at least one surface of the porous film in the present invention, it is possible to impart metallic luster, design properties, high heat insulating properties, and surface conductivity.

  The metal layer in the present invention includes, for example, metal components such as Al, Cu, Ag, Si, nickel, copper, gold, silver, chromium, zinc, tin, silicon, magnesium, and oxides thereof. Is preferred.

  As a method for forming the metal layer, for example, a physical vapor deposition method or a chemical vapor deposition method of metal can be used, but the method is not limited thereto.

  In the present invention, the chemical vapor deposition method on the porous film includes a plasma CVD method, a photo CVD method, and the like, but the chemical vapor deposition method generally has a slow film formation rate and low productivity. The physical vapor deposition method includes a vacuum vapor deposition method and a sputtering method. In particular, in order to achieve the object of the present invention of producing a metallized porous film having high permeability, a porous film as a base material. Since the amount of heat received is small, there is little whitening, shrinkage, tearing, wrinkles, etc. (those skilled in the art sometimes refer to this phenomenon as “heat loss”) and heat production is superior. preferable.

  Explaining the vacuum deposition method, this method is a method in which a roll-shaped film is unwound, vapor deposition is performed while being in close contact with a cooled drum, and the process of winding in a roll shape is performed in a device kept under reduced pressure. It is.

  Examples of the evaporation source include a resistance heating type boat type, a crucible type by radiation or high frequency heating, a method by electron beam heating, and the like. Beam evaporation is preferred.

  The metal used for forming the metal layer is preferably aluminum and / or aluminum oxide from the viewpoint of durability, productivity and cost of the metal layer. At this time, other metal components such as nickel, copper, gold, silver, chromium, zinc, tin, silicon, and magnesium can be used simultaneously or sequentially with aluminum. These metals are preferably processed into a granular, rod-shaped, tablet-shaped, wire-shaped or crucible shape with a purity of 99% or more, desirably 99.5% or more.

  The thickness of the metal layer is preferably 20 nm or more because the uniformity, designability, and heat insulation of the metal layer can be kept good in some cases. More preferably, it is 30 nm or more. Although there is no particular upper limit on the thickness of the metal layer, it is preferably less than 500 nm from the viewpoint of economy and productivity.

  In order to make the thickness of the metal layer within the above range, for example, when the metal layer is formed by vapor deposition, it is preferable that the transport tension of the porous film in the vacuum chamber apparatus is 2 to 50 N / m. Here, the unit of conveyance tension “N / m” indicates the tension applied per unit width of the film. If it is less than the above range, wrinkles may occur on the film, tears or wrinkles may occur, productivity may be impaired, or contact time with the cooling drum may be shortened, resulting in heat tears and wrinkles. May be impaired. If the above range is exceeded, cracks may occur in the metal layer. More preferably, it is 2-45 N / m, More preferably, it is 2-40 N / m.

  For example, when the metal layer is formed by vapor deposition, it is important that the surface temperature of the cooling drum to be used is within a range of −40 to 0 ° C. If the temperature of the cooling drum is less than the above range, the economy may be inferior. On the other hand, if it is above the above range, the transparency of the metallized porous film may be lost due to heat loss of the film. More preferably, it is -30 to 0 degreeC, More preferably, it is -30 to 0 degreeC.

  Furthermore, it is important to improve the adhesion of the film to the metal drum. When the surface of the film transport roll is rough or the transport tension is out of the above range, the adhesion of the film to the metal drum may be reduced, and heat loss may occur due to poor heat transfer.

  In order to improve the adhesion, in addition to the above tension and cooling drum temperature conditions, the roll arrangement in the vapor deposition machine for keeping the film transport angle properly and the material having a good roll surface are appropriately designed in advance. This is very important.

  When the metal layer is formed by vapor deposition, after vapor deposition, in order to saturate the structural change of the metal layer over time and increase the density, the inside of the vacuum vapor deposition apparatus is returned to normal pressure and the wound film is rewound. Is preferred. Aging is preferably performed at a temperature of 20 to 50 ° C. for 1 to 3 days, and more preferably, aging is performed in an environment with a humidity of 60% or more and no condensation.

Moreover, when forming a metal oxide layer on the porous film, aluminum oxide is preferable from the viewpoint of durability, productivity, and cost of the metal layer. These vapor deposition methods can be performed by a known method. For example, in the case of an aluminum oxide film, the film is run in an advanced vacuum apparatus having a degree of vacuum of 1.5 × 10 ⁻² Pa or less to heat the aluminum metal. It melts and evaporates, a small amount of oxygen gas is supplied to the evaporation site, aluminum is agglomerated and deposited on the film surface while oxidizing aluminum, and a vapor deposition film is attached. Further, when performing transparent metal vapor deposition, it is basically necessary to control the amount of metal evaporation and the amount of oxygen gas introduced in order to control the degree of oxidation of the metal-based oxide constituting the metal layer. If the amount of metal evaporation is constant, the degree of oxidation decreases if the amount of introduced oxygen gas is reduced, and the degree of oxidation increases if the amount of introduced oxygen gas is increased. On the contrary, if the amount of introduced oxygen gas is constant, the degree of oxidation increases if the amount of metal evaporation is reduced, and the degree of oxidation decreases if the amount of metal evaporation is increased. At this time, the oxygen gas is preferably supplied in the same direction as the flow direction of the metal vapor from the side of the vapor deposition source.

  In order to form the metal layer, for example, a vacuum vapor deposition apparatus as shown in FIG. 3 is used. In this vacuum deposition apparatus 4, the porous film according to the present invention travels from the unwinding roll unit 6 to the winding roll unit 11 through the cooling drum 9 inside the vacuum chamber 5. At that time, the metal material 12 in the crucible 16 is vapor-deposited on the porous film on the cooling drum 9 while being heated and evaporated by the electron beam 14 irradiated from the electron gun 13. At this time, in the case of forming a metal oxide layer, the oxygen supply nozzle 17 may be installed, oxygen gas may be introduced therefrom, and evaporation may be performed while oxidizing the evaporated metal.

  When forming metal layers on both sides, after depositing a metal or metal-based oxide on one surface (first side), remove the porous film deposited on one side from the take-up roll part 11 and remove it from the take-up roll part. In the same manner, a metal or a metal oxide is deposited on the opposite surface (second surface). In the case of oxidation vapor deposition, the oxygen supply nozzle 17 is installed right next to the crucible 16 as the vapor deposition source so that the degree of oxidation can be easily controlled and the metal vapor and oxygen gas flow in the same direction. do it. As a result, the reaction space between the metal vapor and oxygen gas becomes large.

Here, the inside of the vacuum chamber 5 is preferably decompressed to 1.0 × 10 ^{−8 to} 1.5 × 10 ⁻² Pa. Further, in order to form a dense metal layer having few deteriorated portions, it is preferable to reduce the pressure to 1.0 × 10 ^{−6 to} 1.0 × 10 ⁻³ Pa.

  The electron beam 14 is preferably output with an output in the range of 2.0 to 8.0 kW. More preferably, it is 3.0-7.0 kW, More preferably, it exists in the range of 4.0-6.0 kW. Note that the metal material 19 may be heated and evaporated by directly heating the crucible.

  The oxygen gas is introduced into the vacuum chamber 5 at a flow rate of 0.5 to 10 L / min using the gas flow rate control device 19. More preferably, it is 1.5-8 L / min, More preferably, it is 2.0-5 L / min.

  As for the conveyance speed of the porous film in the inside of the vacuum chamber 5, 20-200 m / min is preferable. More preferably, it is 30-100 m / min, More preferably, it is 40-80 m / min. If the conveying speed is too slower than 20 m / min, the film may lose heat and impair the permeability. Further, in order to control the thickness of the metal layer as described above, it is necessary to considerably reduce the evaporation amount of the metal, which makes it difficult to control. When the conveyance speed is faster than 200 m / min, it is difficult to uniformly control the amount of metal evaporation.

  Further, a laminate layer may be provided on the metal layer to such an extent that the permeability is not impaired.

  The thickness of the metal layer in the present invention is preferably in the range of 10 to 500 nm. By being in this range, economic efficiency and productivity can be improved. More preferably, it is 20-300 nm, Most preferably, it is 30-200 nm. The thickness of the metal layer can be controlled by the film conveyance speed, the energy applied when the metal is evaporated, and the like.

  The gloss of the metal layer of the metallized porous film of the present invention is preferably 100% or more. As a method for imparting high gloss to the metal layer in the present invention, for example, when the metal layer is formed on the porous film, as described above, the base film does not lose heat, In forming the layer, a high-purity metal can be used. In order to prevent heat loss of the film, for example, it is possible to improve the adhesion of the film to the cooling drum or to lower the temperature of the cooling drum. The temperature of the cooling drum at that time is preferably −60 to 0 ° C., preferably −50 to −10 ° C., and most preferably −40 to −20 ° C. When the glossiness of the surface of the metal layer of the metallized porous film of the present invention is 100% or more, the metallic gloss is satisfactorily exhibited and design properties can be imparted, which is preferable. More preferably, it is the range of 100-700%, More preferably, it is the range of 100-500%.

  The surface resistivity of the metal layer of the metallized porous film of the present invention is preferably 100Ω / □ or less, more preferably 0.1 to 100Ω / □. Thereby, for example, when the metallized porous film is used as an electrode member of a battery, it can contribute to reducing the resistance of the entire battery, which is preferable. The surface specific resistance can be controlled by the thickness of the metal layer, the metal type, and the like. In the case of vapor deposition of a metal-based oxide, the surface resistance can be controlled by adjusting the oxygen gas introduction amount at the time of vapor deposition, the position of the oxygen gas supply nozzle, the evaporation amount of the metal component, and the film conveyance speed. In particular, the effects of metal evaporation and film transport speed are large. The surface specific resistance is more preferably in the range of 0.5 to 10Ω / □.

  The metallized porous film of the present invention has permeability. One method for defining the permeability is Gurley air permeability. The Gurley air permeability of the metallized porous film of the present invention is 1 to 10,000 seconds / 100 ml. That the Gurley air permeability of the metallized porous film of the present invention is in the above range corresponds to the air permeability of the entire sheet.

  The smaller the value of the Gurley air permeability of the metallized porous film of the present invention, the higher the permeability of the entire metallized porous film. If the value of the Gurley air permeability is too small, the film is likely to be broken and the film-forming property may be lowered (the film is cut in the stretching step), so that it is preferably 1 second / 100 ml or more, for example.

  In the metallized porous film of the present invention, when the Gurley air permeability exceeds 10,000 seconds / 100 ml, it may not substantially have permeability. On the other hand, in the metallized porous film of the present invention, when the Gurley air permeability is less than 1 second / 100 ml, the metallized porous film may be unstable.

  In order to obtain a metallized porous film having a Gurley air permeability of 1 to 10,000 seconds / 100 ml, a porous film having, as a base material, the polyolefin of the present invention as a main component and uniform and dense pores. It is important to use Preferably, it is important to use a porous film excellent in permeability that satisfies the above-described more preferable embodiment. From the viewpoint of stabilizing continuous film formation and production, the Gurley air permeability is most preferably 50 to 500 seconds / 100 ml. Furthermore, in order to prevent the porous film from losing heat and closing the holes, for example, by improving the adhesion of the film to the cooling drum as described above, or by reducing the temperature of the cooling drum, It is very important to form a metal layer on at least one side. The temperature of the cooling drum at that time is preferably −60 to 0 ° C., preferably −50 to −10 ° C., and most preferably −40 to −20 ° C.

  The metallized porous film of the present invention has pores, and the average pore diameter of this film is in the range of 35 to 500 nm. When the average pore size is in the range of 35 to 500 nm, good permeability and selective permeability can be imparted to the metallized porous film.

  If the pore diameter is less than the above range, the permeability may be lowered. When the pore diameter exceeds the above range, the film-forming property is deteriorated, and the film may be cut during film formation. Moreover, the durability of the film may be reduced. Moreover, there is no selective permeability and it may be inferior in design property. The average pore diameter of the metallized porous film of the present invention is preferably 35 to 400 nm, more preferably 40 to 400 nm, and still more preferably 40 from the viewpoint of achieving both continuous film formation and production stability and excellent permeability. It is -200 nm, Most preferably, it is 45-200 nm.

  In order to obtain a metallized porous film having an average pore diameter of 35 to 500 nm, the base material of the metallized porous film is mainly composed of polyolefin in the present invention, and has uniform and dense pores, preferably A porous film satisfying the above-described more preferable embodiment is used. Furthermore, in order to prevent the porous film from losing heat and blocking the pores, for example, by improving the adhesion of the film to the cooling drum or by lowering the temperature of the cooling drum, a metal layer is formed on one side of the film. Form. The temperature of the cooling drum at that time is preferably −60 to 0 ° C., preferably −50 to −10 ° C., and most preferably −40 to −20 ° C. For example, by producing as described above, a metallized porous film having an average pore diameter of 35 to 500 nm can be obtained.

  Here, in the present invention, the average pore diameter is measured according to the so-called bubble point method of JIS K 3832 (1990).

  The metallized porous film of the present invention preferably has a porosity of 20% or more, more preferably 20 to 95%. When the porosity is 20% or more, and further 20 to 95%, it is preferable because good permeability can be imparted to the metallized porous film.

  The higher the porosity of the metallized porous film of the present invention is, the better the above characteristics tend to be. However, if the porosity is too high, the film tends to stretch, wrinkle, or break in the film-forming process or the subsequent secondary processing process (the person skilled in the art has a tendency to see these phenomena, The film is said to be inferior in process passability, secondary processability or handleability). Therefore, the porosity of the porous film in the present invention is more preferably 20 to 85%, more preferably 35 to 90%, still more preferably 60 to 85%, and most preferably 65 to 85%.

  The porosity can be controlled by the draw ratio and the β crystal fraction. The higher the draw ratio and the higher the β crystal fraction, the greater the porosity of the metallized porous film.

  The breaking elongation in the machine direction (MD) of the metallized porous film of the present invention is in the range of 10 to 300%. When the breaking elongation in the MD direction of the metallized porous film is in the range of 10 to 300%, the metallized porous film has excellent durability, good handling properties, and excellent productivity. The toughness of the sheet is improved, and durability can be improved when used for applications such as battery separators. If the elongation is above the above range, the metal layer may crack. On the other hand, if it is less than the above range, the film may be broken in the processing step.

  The range of the breaking elongation in the MD direction of the metallized porous film of the present invention is preferably 20 to 100%, more preferably 30 to 80%, and most preferably 30 to 70%. The breaking elongation in the MD direction can be controlled, for example, by the draw ratio in the machine direction and transverse (TD) direction of the film.

  The thickness of the metallized porous film of the present invention is preferably 5 to 200 μm. If it is within the above range, the film is stiff and may be difficult to wrinkle during further processing. Moreover, it is excellent in economical efficiency and productivity as it is the said range. The thickness of the metallized porous film of the present invention is more preferably 7 to 40 μm, further preferably 8 to 35 μm, and most preferably 9 to 30 μm. The thickness of the metallized porous film can be controlled by the stretching ratio and β crystal fraction in the machine direction and the transverse direction of the film, and can be controlled by the polymer discharge amount and the production rate at the time of melt extrusion.

  Hereinafter, an example of a preferable use will be shown when the metallized porous film of the present invention is used. Since the metallized porous film of the present invention has high elongation as described above, it has excellent processability, handling properties, and durability when performing secondary processing for each application.

  Compared with a sheet made of a metal substrate and a substrate having transparency and a metal substrate, the metallized porous film of the present invention has a conventional permeability. Since it does not require a complicated process, it is excellent in productivity. Further, compared to a metallized sheet using a physically perforated substrate, the metallized porous film of the present invention has extremely small holes, so that, for example, it allows vapor to pass but not water (moisture permeable and waterproof). Selective permeability. Furthermore, since it has many uniform and dense holes, it has excellent permeability.

  Even if the porous film has a metal layer on the surface, the entire sheet is permeable.

  In particular, when used as a separator for a battery, it is preferable because it prevents the passage of dendrites generated on the electrode and has a high piercing property compared to a nonwoven fabric or the like.

  Most of current batteries have a configuration in which a porous film and an electrode are separated. By using the metallized porous film of the present invention as the separator and the electrode, it leads to simplification of the process when manufacturing the battery.

  The metallized porous film of the present invention is excellent in heat insulation and heat retention, and has permeability, so when used for building materials, for example, house wrap, it exhibits an excellent heat retention effect and keeps the room temperature constant. Since it can be held, it contributes to the reduction of heating and cooling costs, which is favorable from the viewpoint of economy. Moreover, since it has permeability | transmittance, it can contribute to preventing dew condensation in winter, and it is preferable.

  The metallized porous film of the present invention is excellent in permeability, elongation, heat insulation, metallic gloss, surface specific resistance and the like by having the above-described configuration. The metallized porous film of the present invention, taking advantage of the above-mentioned characteristics, imparts a function of adjusting indoor humidity while being excellent in heat retention and durability when used for building materials such as house wrap. Can do. Further, when used as a decorative material, for example, a decorative film, the member can be provided with transparency and the surface can be provided with metallic luster.

  The metallized porous film of the present invention is preferable for use as a packaging material for disposable body warmers. Since the metallized porous film of the present invention has permeability, it can transmit oxygen and promote the reaction of the exothermic composition. Moreover, since it is excellent in heat retention, heat insulation, and durability, it can contribute to maintaining the heat of the warmer for a long time, which is preferable.

  The metallized porous film of the present invention is preferably used as a sheet in a watch equipped with a solar cell. Since the metallized porous film of the present invention has transparency and high glossiness, it is preferable because it reflects light and brightens the dial. Furthermore, since the metallized porous film of the present invention is excellent in concealability, the dark purple characteristic of solar cells can be made inconspicuous from the outside, which is preferable. Further, the metallized porous film of the present invention is preferable because the production cost is lower and the pore formation is more uniform and denser than the timepiece sheet provided with the conventional solar cell or solar battery. Moreover, since it has metallic luster and is excellent in design, it is preferable because it does not impair the appearance decoration as a watch.

  Since the metallized porous film of the present invention has permeability and is excellent in heat insulation and heat retention, it is placed on a golf course green or tee ground to protect the green from frost or freezing. It is preferable to use it as a protective sheet. Since the metallized porous film of the present invention has uniform pores, it is possible to reliably prevent turf from suffocating and dying. In addition, since the metallized porous film of the present invention is excellent in heat insulation and heat retention, it is possible to effectively retain green and the like by using geothermal heat more effectively.

  It is preferably used as a sheet having a metal layer used in a device for displaying a color image, for example, a display device (sometimes abbreviated as SED) provided with a surface conduction electron-emitting device.

  The metallized porous film of the present invention has a metallic luster and can increase display brightness. Furthermore, since the metallized porous film of the present invention has permeability, it is preferable because the gas generated during firing of the adhesive can be efficiently removed in the manufacturing process of the display device. It is preferable because it can prevent the sheet from being torn or deformed by gas and can reduce the influence on other members.

  The metallized porous film of the present invention is preferred for use as a molded product for photographic photosensitive material packaging. Since the metallized porous film of the present invention has a metallic gloss and excellent light shielding properties, it is preferable as a packaging material for a photographic photosensitive material that is affected by light. In addition, since the metallized porous film of the present invention has permeability, it is released from the packaging material used for the interior (inner layer), moisture, X-rays, static electricity and oxidation / reduction action that adversely affect the photographic photosensitive material. It is preferable because it can release chemical substances having a odor to the outside.

  Since the metallized porous film of the present invention is excellent in heat insulation and heat retention, it is intended to improve heat retention in equipment that requires heat insulation such as rice cookers, electric water heaters, beverage bottles and cooking pots. It is preferable to use as a member of a heat insulating cover. When used during operation of a heat retaining device such as a rice cooker or electric water heater that has steam holes and discharges high-temperature steam from the steam holes, the water vapor adheres as water droplets inside the heat insulating cover and the interior is abnormally hot. Therefore, there was a risk of resin deformation or ignition of the casing of the heat insulation device. Since the metallized porous film of the present invention has permeability, when applied to a heat retaining device having a steam hole, a steam passage can be formed, thereby suppressing the steaming and abnormally high temperature inside the heat insulating cover. This is preferable because the heat insulating cover can be applied even during operation of the heat retaining device. Moreover, since the metallized porous film of the present invention has a high infrared reflectance, it can reduce heat transfer due to radiation from the object to be heated to the outside, improve the heat retention of the heat retaining device, and reduce the amount of energy consumed. Since it can reduce, it is preferable. Moreover, since the metallized porous film of the present invention has a metallic luster and is excellent in design, it is preferable because it does not impair the decorative appearance as a heat retaining device.

(Characteristic measurement method)
Terms and measurement methods commonly used in the present invention will be described together below.

(1) Confirmation of β crystal activity The metallized porous film of the present invention is used as a sample. Measurement was performed according to JIS K 7122 (1987) using a Seiko Denshi Kogyo thermal analyzer RDC220.

  The film was charged in an aluminum pan with a weight of 4.5 to 5.5 mg, set in the apparatus, heated from 30 ° C. to 280 ° C. at a rate of 10 ° C./min in a nitrogen atmosphere, and the temperature rising was completed. After waiting for 5 minutes at 280 ° C., subsequently cooling to 30 ° C. at a rate of 10 ° C./minute, waiting for 30 minutes at 30 ° C. after completion of cooling, and then raising the temperature to 280 ° C. again at a rate of 10 ° C./minute When an endothermic peak (symbol 2 in FIG. 2) accompanying melting of a β crystal having an apex at 140 ° C. or more and less than 160 ° C. is observed in the heat quantity curve obtained in FIG. It was determined to have crystal activity. In addition, the endothermic peak here means that whose heat of fusion is 10 mJ / mg or more. The caloric curve obtained at the first temperature rise may be referred to as a first run caloric curve, and the caloric curve obtained at the second temperature rise may be referred to as a second run caloric curve. The heat of fusion is the area enclosed by the baseline and the calorific curve until the heat curve is shifted from the baseline to the endothermic side as the temperature rises and then returns to the baseline position. A straight line was drawn on the high temperature side to the intersection of the calorific curves, and this area was determined by computer processing. From FIG. 2, the reference numeral 2 indicates the heat of fusion of the endothermic peak accompanying the melting of the β crystal, and the reference numeral 3 indicates the heat of fusion of the endothermic peak accompanying the melting of the crystal other than the β crystal. When confirming the β crystal activity of the raw material polypropylene chip, the same procedure as described above may be used. In the tables of the examples, those having β crystal activity were set to Yes, and those having no β crystal activity were set to No.

  In the above calorimetric curve, there is a melting peak having an apex at 140 to 160 ° C., but when it is unclear whether it is caused by melting of the β crystal, there is an apex of the melting peak at 140 to 160 ° C., A sample prepared under the following conditions may be determined to have β crystal activity when the K value calculated from each diffraction peak intensity of the diffraction profile obtained by the 2θ / θ scan is 0.3 or more.

  The sample preparation conditions and the measurement conditions of the wide angle X-ray diffraction method are shown below.

  Sample: The porous film in the present invention was aligned, and the samples were stacked so that the sample thickness after hot press preparation was about 1 mm. This sample was sandwiched between two aluminum plates having a thickness of 0.5 mm, and was hot-pressed at 280 ° C. to be melted / compressed so that the polymer chains were substantially non-oriented. The obtained sheet was crystallized by being immersed in boiling water at 100 ° C. for 5 minutes immediately after taking out the whole aluminum plate. Thereafter, a sample obtained by cutting a sheet obtained by cooling in an atmosphere at 25 ° C. was subjected to measurement.

  Wide-angle X-ray diffraction method measurement conditions: An X-ray diffraction profile was obtained by 2θ / θ scan in accordance with the above conditions.

Here, K value is observed at around 2 [Theta] = 16 °, (a Hbeta ₁₎ diffraction peak intensity of β due to crystal (300) plane are observed respectively in the vicinity of 2θ = 14,17,19 °, From the diffraction peak intensities of the (110), (040), and (130) planes (referred to as Hα ₁ , Hα ₂ , and Hα ₃ , respectively) due to the α crystal, it can be calculated by the following mathematical formula. The K value is an empirical value indicating the ratio of β crystals. For details of the K value, such as the calculation method of each diffraction peak intensity, see A. Turner Jones et al., “Macromoleculare Chemie” (Macromoleculare Chemie). ), 75, pages 134-158 (1964).

K = Hβ ₁ / {Hβ ₁ + (Hα ₁ + Hα ₂ + Hα ₃ )}
The structure of the polypropylene crystal type (α crystal, β crystal), the obtained wide-angle X-ray diffraction profile, etc. are described in, for example, Edward P. Moore Jr. Written by "Polypropylene Handbook", Industrial Research Committee (1998), p. 135-163; Hiroyuki Tadokoro, “Structure of Polymer”, Kagaku Dojin (1976), p. 393; A. Turner Jones et al., “Macromoleculare Chemie”, 75, 134-158 (1964), and there are many reports including references cited therein. You can refer to it.

(2) β crystal fraction
The metallized porous film of the present invention is used as a sample. In the method of (1) above, in the caloric curve of second run obtained when the rate of temperature rise and cooling at the time of measurement is 10 ° C./min (for example, reference numeral 1 in FIG. 1), 140 ° C. or higher and lower than 160 ° C. The heat of fusion calculated from one or more endothermic peaks accompanying melting of the β crystal whose apex is observed at (ΔHβ; for example, symbol 2 in FIG. 2) and polypropylene other than the β crystal whose apex is observed at 160 ° C. or higher. It calculated | required using the following formula from the calorie | heat amount ((DELTA) H (alpha); the code | symbol 3 of FIG. 2 as an example) calculated from the endothermic peak accompanying the melt | dissolution of the crystal | crystallization of origin. At this time, a slight exothermic or endothermic peak may be observed between the melting peak of ΔHβ and the melting peak of ΔHα, but this peak may be deleted.

β crystal fraction = {ΔHβ / (ΔHβ + ΔHα)} × 100
The same measurement was performed 5 times for the same sample, and the average value of the obtained β crystal fraction was defined as the β crystal fraction of the sample (unit:%). Also, when evaluating the difference in β-crystal fraction due to process conditions, such as when measuring unstretched sheets manufactured under various casting conditions, measure under the same conditions as above except using a first run caloric curve. Can be done.

(3) Discrimination of orientation The porous film in the present invention is used as a sample. When using a metallized porous film as a sample, if the metal layer is made of aluminum, immerse the metallized porous film in dilute hydrochloric acid for one week, and if the metal layer is made of aluminum oxide, The following measurements are performed on the porous film from which the metal layer has been removed by wiping the surface of the metal layer with gauze soaked with hydrofluoric acid. The orientation state of the film is determined from an X-ray diffraction photograph obtained when X-rays are incident on the film from the following three directions.

• Through incidence: incident perpendicular to the surface formed in the longitudinal direction (MD) and transverse direction (TD) of the film • End incident: incident perpendicular to the surface formed in the lateral direction / thickness direction of the film • Edge incident: Incident perpendicular to the surface formed in the longitudinal and thickness directions of the film.

  In addition, the sample aligned the direction, piled up so that thickness might be set to about 1 mm, cut out, and used for the measurement.

  X-ray diffraction photographs were measured by the imaging plate method under the following conditions.

・ X-ray generator: 4036A2 type, manufactured by Rigaku Corporation ・ X-ray source: CuKα ray (using Ni filter)
・ Output: 40kV, 20mA
・ Slit system: 1mmφ pinhole collimator ・ Imaging plate: FUJIFILM BAS-SR
・ Photographing conditions: Camera radius (distance between sample and imaging plate)
40 mm, exposure time 5 minutes.

  Here, the non-orientation, uniaxial orientation, and biaxial orientation of the film are described in, for example, Kiyoichi Matsumoto et al., “Journal of the Textile Society”, Vol. 26, No. 12, 1970, p. 537-549; Kiyoichi Matsumoto, “Making a film”, Kyoritsu Shuppan (1993), p. 67-86; Seizo Okamura et al., “Introduction to Polymer Chemistry (Second Edition)”, Kagaku Dojin (1981), p. As described in 92-93, etc., it can be determined according to the following criteria.

・ Non-orientation: Debye-Scherrer ring having substantially uniform intensity in X-ray diffraction photographs in any direction is obtained. ・ (Vertical) uniaxial orientation: Debye having substantially uniform intensity in X-ray diffraction photographs of End incidence. -A Scherrer ring is obtained-Biaxial orientation: A diffraction image in which the diffraction intensity is not uniform is reflected in the X-ray diffraction photograph in any direction reflecting the orientation.

(4) Surface gloss of metal deposition layer (%)
The metallized porous film of the present invention is used as a sample. Based on JIS Z 8741 (1997), the surface of the metal layer of the metallized porous film under the condition of an input / output angle of 60 ° using a digital variable angle gloss meter UGV-5D manufactured by Suga Test Instruments Co., Ltd. The surface glossiness was measured (unit:%). The same measurement was performed 5 times for the same sample, and the average value of the obtained surface glossiness was defined as the surface glossiness of the sample.

(5) Surface specific resistance Since the measurable device differs depending on the range of surface specific resistance, measurement is first performed by the method i), and a sample having a surface specific resistance exceeding 1.0 × 10 ⁶ Ω / □ is ii). Measure with this method. The average value of the five measurement results is defined as the surface specific resistance in the present invention.
i) Low resistivity measurement Measured using the following measuring device in accordance with JIS-K7194 (1994).

Measuring device: Lorester EP MCP-T360 Made by Mitsubishi Chemical Measuring environment: Temperature 23 ° C Humidity 65% RH
Number of measurements: Measure 5 times.
ii) High resistivity measurement Measured using the following measuring device in accordance with JIS-C2151 (2006).

Measuring device: Digital ultra-high resistance / micro ammeter R8340 manufactured by Advantest Corporation Applied voltage: 100V
Application time: 10 seconds Measurement unit: Ω
Measurement environment: Temperature 23 ° C Humidity 65% RH
Number of measurements: Measure 5 times.

(6) Gurley air permeability The metallized porous film of the present invention is used as a sample. Based on JIS P 8117 (1998), it was measured at 23 ° C. and 65% RH (unit: second / 100 ml). The same measurement was performed 5 times for the same sample, and the average value of the obtained Gurley air permeability was taken as the Gurley air permeability of the sample. At this time, the case where the average value of the Gurley air permeability exceeds 10,000 seconds / 100 ml is regarded as having substantially no permeability, and is set to infinity (∞) seconds / 100 ml.

(7) Average pore diameter The metallized porous film of the present invention is used as a sample. POROUS MATERIALS, Inc. Bubble points were measured using an automatic pore size distribution measuring device “PERM-POROMETER”. Measurement conditions are as follows.

Test solution: 3M “Fluorinert” FC-40
Test temperature: 25 ° C
Test gas: Air Analysis software: Capwin
Measurement conditions: Automatic measurement under default conditions of Capillary Flow Porometry-Wet up, Dry down In the bubble point method, the following relational expression is established between the pore diameter (pore diameter) and the test pressure.

d = Cγ / P × 10 ³
[However, d: pore diameter (nm), C: constant, γ: surface tension of fluorinate (16 mN / m), P: pressure (Pa). ]
Here, based on the above, the average pore diameter was calculated from the 1/2 half-wetting curve using the data analysis software attached to the apparatus. This measurement is also described in detail in the manual attached to the device. The same measurement was performed five times for the same sample, and the average value of the average pore diameters obtained was defined as the average pore diameter of the sample (unit: nm).

(8) Porosity The metallized porous film of the present invention is used as a sample. Using a high-precision electronic hydrometer (SD-120L) manufactured by Mirage Trading Co., Ltd., a sample cut out to a size of 30 × 40 mm is 23 ° C. according to JIS K 7112 (1999) A method (underwater substitution method). Measured at 65% RH. The same measurement was performed 5 times for the same sample, and the average value of the obtained specific gravity was defined as the specific gravity (d1) of the sample.

  The sample was sandwiched between 0.5 mm thick aluminum plates, melted and compressed by hot pressing at 280 ° C., and then the obtained sheet was immersed in water at 30 ° C. together with the aluminum plate and rapidly cooled. About the obtained sheet | seat, the same measurement was performed about the same sample 5 times, and the average value of the obtained specific gravity was made into the specific gravity (d0) after sample preparation. From the obtained d1 and d0, the porosity of the film was determined using the following formula (unit:%).

Porosity (%) = {1-d1 / d0} × 100
It should be noted that only when the porous film absorbs water inside, the mass (g) and the thickness of the film of the above size are separately measured, and d1 may be obtained from the obtained volume (cm ³ ).

(9) Longitudinal breaking elongation According to JIS K 7127 (1999, test piece type 2), using a film strong elongation measuring device (AMF / RTA-100) manufactured by Orientec Co., Ltd., 25 ° C, Measured at 65% RH. The sample was cut into a size of 15 cm in the vertical direction and 1 cm in the horizontal direction, stretched at an original length of 50 mm, and a tensile speed of 300 mm / min, and the elongation at break (unit:%) was measured. The same measurement was performed five times for the same sample, and the average value of the obtained elongation at break was defined as the elongation at break in the longitudinal direction of the sample.

(10) Melt flow rate (MFR)
Measured in accordance with JIS K 7210 (1999) under condition M (230 ° C., 2.16 kgf (21.18 N) (unit: g / 10 min) MFR obtained by performing the same measurement 5 times on the same sample Was the MFR of the sample.

(11) Average particle diameter of particles The volume average diameter measured using a centrifugal sedimentation method (using CAPA500 manufactured by Horiba, Ltd.) was defined as the average particle diameter (μm).
(12) Thickness of metallized porous film and porous film Dial gauge thickness gauge (JIS B 7503 (1997), UPAIGHT DIAL GAUGE (0.001 × 2 mm) manufactured by PEACOCK, No. 25, measuring element 5 mmφ flat type, 125 gf load), 10 points were measured at 10 cm intervals in the vertical and horizontal directions of the film, and the average value thereof was defined as the film thickness of the sample (unit: μm).

(13) Effective stretch ratio An unstretched film extruded from a slit-shaped base, cast on a metal drum and cooled and solidified on a sheet, and each side of a square having a length of 1 cm is parallel to the longitudinal and lateral directions of the film. The film was stretched and wound, and the length (cm) of the resulting film was measured for 10 squares in the vertical direction and 10 squares in the horizontal direction, and the average values were respectively obtained. The effective draw ratio in the machine and transverse directions was used.

(14) Having a nucleus-free hole and confirmation of the thickness of the metal layer In order to confirm that the porous film has a nucleus-free hole and the thickness of the metal layer, the following method was used.

An ultra-thin slice having a cross section in the transverse direction-thickness direction of the porous film was collected using an ultramicrotome by a resin embedding method using an epoxy resin. The collected sections were stained with RuO ₄ and the cross section was observed using a transmission electron microscope (TEM) under the following conditions. Sample preparation and cross-sectional observation were performed at Toray Research Center.

-Apparatus: Transmission electron microscope (TEM) H-7100FA manufactured by Hitachi, Ltd.
・ Acceleration voltage: 100 kV
Observation magnification: 40,000 times Collected images were observed from one surface of the film to the other surface, with one side of the image parallel to the lateral direction of the film and continuously parallel to the thickness direction. To do. At this time, the size of each image is adjusted so that one side parallel to the horizontal direction is 5 μm as the actual size of the film. An OHP sheet (an OSON sheet dedicated to EPSON manufactured by Seiko Epson Corporation) was placed on the obtained images. Next, of the observed holes, if there were observed nuclei inside the holes, only the nuclei were painted black on the OHP sheet with a magic pen. An image of the obtained OHP sheet was read under the following conditions.

・ Scanner: GT-7600U manufactured by Seiko Epson Corporation
-Software: EPSON TWAIN ver. 4.20J
・ Image type: Line drawing ・ Resolution: 600 dpi
The obtained image was transferred to Image-Pro Plus, Ver. Image analysis was performed using 4.0 for Windows. At this time, spatial calibration was performed using the scale of the captured cross-sectional image. The measurement conditions were set as follows.

  -Fill the outline format in the display option settings in the count / size option.

  -In the object extraction option settings, set the exclusion on the boundary to None.

  ・ Automatic extraction of dark objects for the brightness range selection setting during measurement.

  Under the above conditions, the percentage of the total area of the film, that is, the area of the nucleus (blackened portion) to the transverse direction × thickness direction = 5 μm × film thickness (measured in the above (12)) as a measurement target And calculated as the area ratio (R) of the nucleus (unit:%). From this, when the ratio which a nucleus occupies for the whole area of a film is 3% or less, it defined as the said film having a non-nuclear hole, and was set as Yes. Moreover, since the film in which the ratio R exceeds 3% does not have a non-nucleated hole, it was No.

(Example)
The present invention will be described based on examples. In addition, in order to obtain a film having a desired thickness, the polymer extrusion amount was adjusted to a predetermined value unless otherwise specified. In addition, the determination of β crystal activity, β crystal fraction, and porosity of the film are values measured for the entire metallized porous film obtained.

(Example 1)
A polypropylene resin A having the following composition was prepared.
<Polypropylene resin A>
Polypropylene: Polypropylene WF836DG3 (melt flow rate (MFR): 7 g / 10 min) manufactured by Sumitomo Chemical Co., Ltd. 99.95% by weight
β crystal nucleating agent: N, N′-dicyclohexyl-2,6-naphthalene dicarboxamide (NU-100, manufactured by Shin Nippon Rika Co., Ltd.) 0.05% by weight
0.15 parts by weight of IRGANOX 1010 manufactured by Ciba Specialty Chemicals Co., Ltd. as an antioxidant and 0.1 weight of IRGAFOS 168 manufactured by Ciba Specialty Chemicals Co., Ltd. as a heat stabilizer are added to 100 parts by weight of this resin composition. Part was added. This is supplied to a twin screw extruder and melted and kneaded at 300 ° C, then extruded into a gut shape, passed through a 20 ° C water bath, cooled, cut to 3 mm length with a chip cutter, and then dried at 100 ° C for 2 hours. did.

  The obtained polypropylene resin A chip was supplied to a single screw extruder, melted and kneaded at 220 ° C., passed through a 400-mesh single-plate filtration filter, and then extruded from a slit-shaped base heated to 200 ° C., with a surface temperature of 120 Cast into a drum heated to ℃ (= casting drum, cast drum; CD) and form into a sheet shape by blowing hot air heated to 120 ℃ using an air knife from the non-drum surface side of the film. And an unstretched sheet was obtained. In addition, the contact time with the metal drum at this time was 40 seconds.

  The obtained unstretched sheet is preheated through a roll group maintained at 120 ° C., passed between rolls maintained at 120 ° C. and provided with a peripheral speed difference, and stretched four times in the longitudinal direction at 120 ° C. to 95 ° C. Cooled down. Subsequently, both ends of the longitudinally stretched film were introduced into a tenter while being held with clips, preheated at 135 ° C., and stretched 6 times in the transverse direction at 135 ° C. Next, heat-fixing was performed at 150 ° C. while giving 5% relaxation in the transverse direction in the tenter, and after uniform cooling, the film was cooled to room temperature and wound up to obtain a porous film having a thickness of 20 μm.

  Next, on the surface of the porous film, the temperature of the can is set to −20 ° C. in a vacuum vapor deposition apparatus, the aluminum metal is heated and melted to evaporate, the aluminum is aggregated and deposited on the film surface, and a 50 nm vapor deposition film is formed. Attached to obtain a metallized porous film.

  The raw material composition and film property evaluation results of the obtained metallized porous film are shown in Tables 1 to 3, respectively. The obtained metallized porous film was excellent in film formability, and had high elongation, β crystal fraction and porosity, and excellent permeability. Moreover, the strength in the vertical direction was high and the handling property was excellent. Moreover, the glossiness was high and the surface specific resistance was small.

(Example 2)
In Example 1, instead of polypropylene resin A, polypropylene resin B having the following composition was used, and the roll and the film temperature when stretching in the machine direction were set to 100 ° C., and the draw ratio was 5 times. Example 2 was a metallized porous film produced under the same conditions as those described above.

<Polypropylene resin B>
Polypropylene: Polypropylene WF836DG3 (melt flow rate (MFR): 7 g / 10 min) manufactured by Sumitomo Chemical Co., Ltd. 96.8 wt%
High melt tension polypropylene having a long chain branch in the main chain skeleton: Polypropylene PF-814 made by Basell (MFR: 3 g / 10 min.) 3% by weight
β crystal nucleating agent: N, N′-dicyclohexyl-2,6-naphthalene dicarboxamide (NU-100, manufactured by Shin Nippon Rika Co., Ltd.) 0.2% by weight
The raw material composition and film property evaluation results of the obtained metallized porous film are shown in Tables 1 to 3, respectively. The obtained metallized porous film was excellent in film formability, and had high elongation, β crystal fraction and porosity, and excellent permeability. Moreover, the strength in the vertical direction was high and the handling property was excellent. Moreover, the glossiness was high and the surface specific resistance was small.

(Example 3)
In Example 2, a metallized porous film produced under the same conditions was used in Example 3 except that the longitudinal draw ratio was 6 times and the metal film to be deposited was 80 nm.

  The raw material composition and film property evaluation results of the obtained metallized porous film are shown in Tables 1 to 3, respectively. The obtained metallized porous film was excellent in film formability, high in elongation and porosity, and excellent in permeability. Moreover, it was excellent in handling property. Moreover, the glossiness was high and the surface specific resistance was small.

Example 4
In Example 2, a metallized porous film produced under the same conditions was used in Example 4 except that aluminum oxide by the following method was used as the metal to be aggregated and deposited on the film surface.

The porous film obtained is set on the unwinding roll section 6 of the vacuum vapor deposition apparatus 4 shown in FIG. 3, and after reducing the pressure to 1.5 × 10 ⁻³ Pa, the cooling drum 9 at −20 ° C. is used. The porous film was run at a conveyance speed of 60 m / min and a conveyance tension of 50 N / m. At this time, 99.99% by weight of aluminum was evaporated by heating with an electron beam (output 5.1 kW) to form an aluminum vapor-deposited thin film layer (thickness 100 nm) and wound up. After vapor deposition, the inside of the vacuum vapor deposition apparatus was returned to normal pressure, and the wound film was rewound with humidification and aged in an environment of 40 ° C. for 2 days to obtain a metallized porous film.

  The raw material composition and film property evaluation results of the obtained metallized porous film are shown in Tables 1 to 3, respectively. The obtained metallized porous film was excellent in film formability, high in elongation and porosity, and excellent in permeability. Moreover, it was excellent in handling property. Moreover, the glossiness was high and the surface specific resistance was small.

(Examples 5 to 9)
In Example 1, as shown in Table 1, the metallized porous films obtained under the conditions shown in Table 2 for the film formation conditions of the porous film and the formation of the metal layer are shown in Tables 5 and 5 respectively. It was set to 9. Each film characteristic evaluation result is shown in Table 3. The obtained metallized porous film had excellent film forming properties and excellent permeability. Further, the elongation was high and the handling property was excellent.

(Comparative Example 1)
A polypropylene resin having the following composition was prepared.

Polypropylene: Polypropylene WF836DG3 (melt flow rate (MFR): 7 g / 10 min) manufactured by Sumitomo Chemical Co., Ltd. 94.95% by weight
High melt tension polypropylene (HMS-PP) having a long chain branching with a melt tension of 20 cN: HMS-PP PF-814 (MFR: 3 g / 10 min) manufactured by Basell 5% by weight
β crystal nucleating agent: N, N′-dicyclohexyl-2,6-naphthalene dicarboxamide (NU-100, manufactured by Shin Nippon Rika Co., Ltd.) 0.05% by weight
[In addition, MS of said HMS-PP is the value measured on condition of take-up speed | velocity | rate of 5 m / min. ]
0.15 parts by weight of IRGANOX 1010 manufactured by Ciba Specialty Chemicals Co., Ltd. as an antioxidant and 0.1 weight of IRGAFOS 168 manufactured by Ciba Specialty Chemicals Co., Ltd. as a heat stabilizer are added to 100 parts by weight of this resin composition. Part was added. This is fed to a twin screw extruder and melted and kneaded at 300 ° C., then extruded into a gut shape, cooled through a 20 ° C. water tank, cut into 5 mm lengths with a chip cutter, and then dried at 100 ° C. for 2 hours. did. The obtained raw material chips are supplied to a single screw extruder, melted and kneaded at 220 ° C., passed through a 200-mesh single plate filter, extruded from a slit-shaped base heated to 200 ° C., and heated to a surface temperature of 120 ° C. Cast into a metal drum (= casting drum, cast drum), and formed into a sheet shape by blowing hot air heated to 140 ° C. using an air knife from the non-drum surface side of the film, and then forming an unstretched sheet Got. In addition, the contact time with the metal drum at this time was 40 seconds.

  The obtained unstretched sheet was preheated through a roll group maintained at 100 ° C., passed between rolls maintained at 100 ° C. and provided with a peripheral speed difference, stretched 4 times in the longitudinal direction, and cooled to 90 ° C. Subsequently, both ends of this longitudinally stretched film were introduced into a tenter while being held with clips, preheated at 135 ° C., and stretched 8 times in the width direction at 135 ° C. Next, heat-fixing was performed at 155 ° C. while giving 5% relaxation in the width direction in the tenter, and after uniform cooling, the film was cooled to room temperature and wound to obtain a porous polypropylene film having a thickness of 25 μm. .

  Next, on the surface of the obtained porous film, the temperature of the cooling drum is set to 25 ° C. in a vacuum vapor deposition apparatus, the aluminum metal is heated and melted to evaporate, and the aluminum is aggregated and deposited on the film surface. A membrane was attached to obtain a metallized porous film. The raw material composition and film property evaluation results of the obtained metallized porous film are shown in Tables 1 to 3, respectively. The obtained metallized porous film was not permeable.

(Comparative Example 2)
In Example 4, a sheet produced under the same conditions except that no metal layer was formed on the porous film was used as Comparative Example 2.

  The raw material characteristics and film characteristic evaluation results of the obtained film are shown in Tables 1 to 3, respectively. The glossiness was low, the surface specific resistance was high, and it did not have design properties.

(Comparative Example 3)
A polypropylene resin D having the following composition was prepared.

<Polypropylene resin D>
Polypropylene: Polypropylene WF836DG3 (melt flow rate (MFR): 7 g / 10 min) manufactured by Sumitomo Chemical Co., Ltd. 100% by weight
0.15 parts by weight of IRGANOX 1010 manufactured by Ciba Specialty Chemicals Co., Ltd. as an antioxidant and 0.1 weight of IRGAFOS 168 manufactured by Ciba Specialty Chemicals Co., Ltd. as a heat stabilizer are added to 100 parts by weight of this resin composition. Part was added. This is supplied to a twin screw extruder and melted and kneaded at 300 ° C, then extruded into a gut shape, passed through a 20 ° C water bath, cooled, cut to 3 mm length with a chip cutter, and then dried at 100 ° C for 2 hours. did.

  The obtained polypropylene resin D chip was supplied to a single screw extruder, melted and kneaded at 220 ° C., passed through a 400-mesh single-plate filtration filter, and then extruded from a slit-shaped base heated to 200 ° C., with a surface temperature of 30 Cast into a drum heated to ℃ (= casting drum, cast drum; CD), and form into a sheet shape by blowing hot air heated to 30 ℃ using an air knife from the non-drum surface side of the film. And an unstretched sheet was obtained. In addition, the contact time with the metal drum at this time was 40 seconds.

  The obtained unstretched sheet is preheated through a group of rolls maintained at 135 ° C., passed between rolls maintained at 135 ° C. and provided with a peripheral speed difference, and stretched five times in the longitudinal direction at 135 ° C. to 95 ° C. Cooled down. Subsequently, both ends of the longitudinally stretched film were introduced into a tenter while being held with clips, preheated at 165 ° C., and stretched 10 times in the transverse direction at 160 ° C. Next, the film was heat-fixed at 165 ° C. while giving 5% relaxation in the transverse direction in the tenter, uniformly cooled, and then cooled to room temperature and wound up to obtain a film. Next, aluminum metal is heated and melted and evaporated on the surface of the porous film in a vacuum vapor deposition apparatus, and aluminum is agglomerated and deposited on the film surface, and a 50 nm vapor deposition film is attached to obtain a metallized porous film. It was. The raw material composition and film property evaluation results of the obtained metallized porous film are shown in Tables 1 to 3, respectively. The resulting metallized porous film was not substantially permeable.

(Comparative Example 4)
In Example 1, a metallized sheet produced under the same conditions except that the temperature of the can of the vacuum evaporation apparatus was 25 ° C. was set as Comparative Example 4.

  The raw material characteristics and sheet characteristic evaluation results of the obtained sheets are shown in Tables 1 to 3, respectively. The obtained sheet had insufficient permeability, low gloss, and no design.

(Comparative Example 5)
A non-woven fabric H1020-8T manufactured by Toray Industries, Inc. was used as a permeable substrate, and a metal layer was formed on the substrate in the same manner as in Example 1. Table 3 shows the characteristic evaluation results of the obtained sheet. The elongation of the obtained sheet was small. Further, the average pore diameter was 500 nm or more.

(Comparative Example 6)
28 parts by mass of polypropylene (manufactured by Sumitomo Mitsui Polyolefin Co., Ltd., trade name: FO-200H: hereinafter referred to as PP), 72 parts by mass of precipitated barium sulfate (trade name: HD, produced by Barite Industries Co., Ltd.), cured castor 3 parts by weight of oil (manufactured by Ito Seiyaku Co., Ltd., trade name: hydrogenated castor oil) and 1 part by weight of calcium stearate (manufactured by Nitto Kasei Co., Ltd., trade name: Ca-St) are mixed using a tumbler mixer. A resin composition was obtained. The obtained resin composition was processed into a pellet form by a vent type twin screw extruder. Using an extruder equipped with a T-die, the pellets are uniaxially stretched at a draw ratio of 8.0 times between a preheat roll heated to 135 ° C. and a draw roll, and have a thickness of 50 μm. A porous resin sheet (total reflectance 93.0% at a wavelength of 550 nm, total reflectance 90.9% at a wavelength of 780 nm, transmittance: 9.0%) was obtained.

  A silver thin film layer having a thickness of 100 nm was formed on a biaxially stretched polyethylene terephthalate sheet having a thickness of 25 μm by a sputtering method. A polyester hot melt adhesive (SK Dyne 5273 manufactured by Soken Chemical Co., Ltd.) was applied to the surface of the plastic sheet where the silver thin film layer was not formed with a gravure coater to form an adhesive layer with a thickness of 5 μm. The plastic sheet and the porous resin sheet were thermally laminated at a temperature of 70 ° C. and adhered.

  The raw material characteristics and sheet characteristic evaluation results of the obtained sheets are shown in Tables 1 to 3, respectively. The obtained sheet was incapable of measuring the Gurley air permeability and had no permeability. In addition, in the film-forming process, the process may be soiled due to the dropping of the filler, which is inappropriate in production.

(Comparative Example 7)
As the sheet substrate, a mesh (300 mesh; mesh size 30 μm; thickness 55 μm) plain-woven with polyester fibers was used. As the hydrogen storage alloy fine powder, MmNi _3.55 Co _0.75 Mn _0.4 Al _0.3 was mechanically pulverized and classified to have an average particle size of about 40 μm. Mixing and stirring to a weight ratio of 5% carbon black powder as a conductive material and 5% methylcellulose aqueous solution (concentration 1%) as an adhesive relative to the weight of the hydrogen storage alloy fine powder, a blade is formed on the entire sheet substrate surface. Was applied to form a conductive layer having a layer thickness of about 0.1 mm. After the conductive layer was sufficiently dried, electroless nickel plating was performed. The bath composition and conditions of the plating solution are as follows.

<Plating solution>
Nickel sulfate 15 g / liter Sodium hypophosphite 14 g / liter Sodium hydroxide 8 g / liter Glycine 20 g / liter PTFE (particle size 0.3 μm) 15 g / liter Surfactant 0.5 g / liter <Condition>
pH 9.5
Bath temperature 90 ° C
Stirring time 40 minutes After performing electroless plating treatment, the plate was sufficiently washed with water and dried under reduced pressure for 5 hours. The resulting metal plating layer had an average thickness of 1 μm. The metal plating layer contained PTFE fine particles dispersed therein.

  The raw material characteristics and sheet characteristic evaluation results of the obtained sheets are shown in Tables 1 to 3, respectively. The obtained sheet had a small elongation at break. Moreover, since the average hole diameter was large, the sheet was inferior in strength, design properties, and selective permeability.

(Comparative Example 8)
Sheets were produced by depositing magnesium on each side of a 75 μm thick microporous polytetrafluoroethylene (PTFE) substrate having a porosity of 80%. The total amount of magnesium deposited was PTFE and stoichiometric. The magnesium coating was evenly distributed on each side of the film and penetrated 5-10 μm deep from the surface.

  The raw material characteristics and sheet characteristic evaluation results of the obtained sheets are shown in Tables 1 to 3, respectively. The obtained sheet does not have sufficient permeability, and exhibits performance in a specific application by forming a specific metal layer on a specific base material (for example, an oxidized polymer) in order to ignite. It is. That is, it cannot be applied to other general purposes. Furthermore, using special base materials, such as an oxidation polymer, is expensive (refer patent document 6).

(Comparative Example 9)
Aluminum is vapor-deposited by high-frequency heating vacuum deposition on both sides of a perforated film with holes (hole diameter 100 μm, hole distribution density 100,000 / m ² ) using a hot needle in a 38 μm thick polyethylene terephthalate film. Then, a metal vapor deposition layer having a thickness of 70 nm was formed to obtain a sheet.

  The raw material characteristics and sheet characteristic evaluation results of the obtained sheets are shown in Tables 1 to 3, respectively. The obtained sheet had a large average hole diameter and was inferior in sheet strength, design properties, and selective permeability (see Patent Document 7).

(Comparative Example 10)
In Example 4, film formation was attempted under the same conditions except that the thickness of the porous film was 0.5 mm.

  The raw material characteristics and sheet characteristic evaluation results of the obtained sheets are shown in Tables 1 to 3, respectively. The resulting film had high Gurley air permeability and poor permeability.

  The metallized porous film of the present invention is excellent in durability, workability and the like as compared with a permeable sheet having a conventional metal layer. Moreover, since the whole sheet has permeability compared to a sheet having a metal layer on a conventional porous substrate, it can be used for a wide range of applications. Furthermore, for example, by using a porous film mainly composed of a thermoplastic resin, particularly polypropylene, there is little tearing at the time of stretching, and the film forming property and productivity are excellent.

It is the figure which showed typically the calorie | heat amount curve obtained when calculating | requiring a beta crystal fraction in the measuring method (12) beta crystal fraction shown below using a differential scanning calorimeter (DSC). In FIG. 1, the heat of fusion (ΔHβ) obtained from the area of the endothermic peak accompanying the melting of the β crystal whose peak is observed at 140 to 160 ° C. and the polypropylene-derived crystal other than the β crystal whose peak is observed at 160 ° C. or higher. It is the figure which showed the calorie | heat amount ((DELTA) H (alpha)) calculated | required from the area of the endothermic peak accompanying melting. It is a schematic diagram of the vapor deposition apparatus used when forming a metal layer.

Explanation of symbols

1 Caloric curve of polypropylene film having β crystal activity 2 Heat of fusion of β crystal (ΔHβ)
3 Heat of fusion of crystals derived from polypropylene other than β crystals (ΔHα)
T temperature Endo. Endothermic direction 4 Vacuum deposition apparatus 5 Vacuum chamber 6 Unwinding roll section 7 Porous film 8 Guide roll 9 Cooling drum 10 Deposition chamber 11 Winding roll section 12 Metal material 13 Electron gun 14 Electron beam 15 Oxygen gas cylinder (* Metal oxide) Used for vapor deposition)
16 Crucible 17 Oxygen supply nozzle (* Used when depositing metal-based oxides)
18 Mask 19 Gas flow control device (* Used for vapor deposition of metal oxide)

Claims (7)

A metallized porous film having a metal layer on at least one side of a porous film containing a polyolefin-based resin, wherein the Gurley permeability is in the range of 1 to 10,000 seconds / 100 ml, and the average pore diameter is 35 to 35. A metallized porous film having a range of 500 nm and a longitudinal elongation of the film of 10 to 300%. The metallized porous film according to claim 1, wherein the porous film is oriented at least uniaxially. The metallized porous film according to claim 1 or 2, wherein the porosity is 20 to 85%. The metallized porous film according to claim 1, wherein the polyolefin resin is polypropylene. The metallized porous film according to claim 4, wherein the porous film has β-crystal activity. The metallized porous film according to any one of claims 1 to 5, wherein the glossiness of the metal layer is 100 to 700%. The metallized porous film according to claim 1, wherein the metal layer has a surface specific resistance of 0.1 to 100Ω / □.

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