TW201819198A - Laminated polyolefin microporous membrane, separator membrane for batteries and manufacturing method thereof, and method for manufacturing laminated polyolefin microporous membrane winder having excellent shutdown characteristics and suiting to provide a uniform thickness to a porous layer - Google Patents

Abstract

The present invention provides a laminated polyolefin microporous membrane, which has excellent shutdown characteristics and suits to provide a uniform thickness to a porous layer. In addition, the present invention further provides a separator membrane for batteries, which is obtained by forming a porous layer having a uniform thickness on a polyolefin microporous membrane and suits to increase the capacity of a battery. The laminated polyolefin microporous membrane having a length of 1000 m or longer, includes a first polyolefin microporous membrane and a second polyolefin microporous membrane, wherein the shutdown temperature is 128-135 DEG C, the air resistance increase rate at 30-105 DEG C is less than 1.5 sec/100ccAir/DEG C per a thickness of 20 [mu]m, and the variation width of an F25 value in the lengthwise direction is 1 MPa or less. Here, the F25 value represents a value obtained by dividing, by the cross-sectional area of a test piece, the load value at which the test piece is elongated by 25% by using a tensile testing machine.

Description

積層聚烯烴微多孔膜、電池用隔膜及其製造方法以及積層聚烯烴微多孔膜捲繞體之製造方法    Laminated polyolefin microporous film, battery separator, method for producing the same, and method for producing laminated polyolefin microporous film roll   

本發明關於一種積層聚烯烴微多孔膜、於積層聚烯烴微多孔膜之至少單面具有多孔層之電池用隔膜及其製造方法。 The invention relates to a laminated polyolefin microporous film, a battery separator having a porous layer on at least one side of the laminated polyolefin microporous film, and a method for manufacturing the same.

熱塑性樹脂微多孔膜作為物質之分離膜、選擇滲透膜及隔膜等被廣泛使用。例如，鋰離子二次電池、鎳氫電池、鎳鎘電池及聚合物電池中使用之電池用隔膜、以及雙電層電容器用隔膜等。 Thermoplastic resin microporous membranes are widely used as material separation membranes, selective osmosis membranes and membranes. For example, separators for batteries used in lithium ion secondary batteries, nickel-metal hydride batteries, nickel-cadmium batteries, and polymer batteries, and separators for electric double-layer capacitors.

特別作為鋰離子二次電池用隔膜，較佳使用聚乙烯製微多孔膜，所述聚乙烯製微多孔膜通過含浸電解液而具有離子滲透性，其電絕緣性優異，且具有孔閉塞功能，所述孔閉塞功能當電池內部異常升溫時於120℃至150℃左右之溫度切斷電流，以抑制過度升溫。然而，由於某種原因導致孔閉塞後電池內部繼續升溫時，可能因聚乙烯製微多孔膜之收縮而發生破膜。該現象並不僅限定於聚乙烯製微多孔膜，於使用其他熱塑性樹脂之微多孔膜中，如果處於樹脂熔點以上則無 法避免。 In particular, as a separator for a lithium ion secondary battery, a polyethylene microporous membrane is preferably used. The polyethylene microporous membrane has ion permeability by impregnating an electrolyte, has excellent electrical insulation, and has a pore blocking function. The hole blocking function cuts off the current at a temperature of about 120 ° C to 150 ° C when the battery is abnormally heated, so as to suppress excessive heating. However, if the inside of the battery continues to heat up after the pores are closed for some reason, the film may break due to the shrinkage of the polyethylene microporous membrane. This phenomenon is not limited to polyethylene microporous membranes, and microporous membranes using other thermoplastic resins cannot be avoided if they are above the melting point of the resin.

特別是鋰離子電池用隔膜與電池特性、電池生產效率及電池安全性密切相關，因此要求其具有機械特性、耐熱性、滲透性、尺寸穩定性、切斷特性、熔融破膜特性(熔斷特性)等。此外，為提高電池之循環特性，要求提高其與電極材料之黏附性，為提高生產效率，要求其提高電解液滲透性等。因此，過去一直在研究通過於微多孔膜上設置多孔層來提高這些功能。 In particular, separators for lithium-ion batteries are closely related to battery characteristics, battery production efficiency, and battery safety, so they are required to have mechanical characteristics, heat resistance, permeability, dimensional stability, cut-off characteristics, and melt-breaking characteristics (melt-off characteristics). Wait. In addition, in order to improve the cycle characteristics of the battery, it is required to improve the adhesion between the battery and the electrode material, and to improve the production efficiency, it is required to improve the electrolyte permeability. Therefore, studies have been conducted in the past to improve these functions by providing a porous layer on a microporous membrane.

另外，本說明書所提及之多孔層係指利用濕式塗層法得到之層。 In addition, the porous layer mentioned in this specification refers to a layer obtained by a wet coating method.

專利文獻1之實施例5中，使用凹版塗佈機於利用同時雙軸拉伸法得到之聚乙烯微多孔膜前驅物上塗佈使二氧化鈦顆粒及聚乙烯醇均勻分散之水溶液後，於60℃進行乾燥將水除去，得到總膜厚24μm(塗佈厚度4μm)之多層多孔膜。 In Example 5 of Patent Document 1, an aqueous solution in which titanium dioxide particles and polyvinyl alcohol were uniformly dispersed was coated on a polyethylene microporous film precursor obtained by a simultaneous biaxial stretching method using a gravure coater, and then at 60 ° C. After drying, water was removed to obtain a multilayer porous film having a total film thickness of 24 μm (coating thickness of 4 μm).

專利文獻2之實施例3中，使用棒式塗佈機於利用同時雙軸拉伸法得到之聚烯烴微多孔膜上塗佈使二氧化鈦顆粒及聚乙烯醇均勻分散之水溶液後，於60℃進行乾燥將水除去，得到總膜厚19μm(塗佈厚度3μm)之多層多孔膜。 In Example 3 of Patent Document 2, an aqueous solution in which titanium dioxide particles and polyvinyl alcohol were uniformly dispersed was applied on a polyolefin microporous film obtained by a simultaneous biaxial stretching method using a bar coater, and then performed at 60 ° C. The water was removed by drying to obtain a multilayer porous film having a total film thickness of 19 μm (coating thickness: 3 μm).

專利文獻3之實施例1中，使用凹版塗佈機於利用同時雙軸拉伸法得到之聚烯烴微多孔膜上塗佈使鋁顆粒及聚乙烯醇均勻分散之水溶液後，於60℃進行乾燥將水除去，得到總膜厚20μm(塗佈厚度4μm)之多層多孔膜。 In Example 1 of Patent Document 3, the polyolefin microporous membrane obtained by the simultaneous biaxial stretching method was coated with an aqueous solution in which aluminum particles and polyvinyl alcohol were uniformly dispersed using a gravure coater, and then dried at 60 ° C. The water was removed to obtain a multilayer porous film having a total film thickness of 20 μm (coating thickness of 4 μm).

專利文獻4之實施例6中，使利用逐次雙軸拉伸法得到之聚乙烯微多孔膜通過適量載有含有間位型全芳香族聚醯胺、氧化鋁顆粒、二甲基乙醯胺(DMAc)及三丙二醇(TPG)之塗佈液之邁耶棒間，經由凝固、水洗及乾燥製程，得到形成有耐熱性多孔質層之非水系二次電池用隔膜。 In Example 6 of Patent Document 4, the polyethylene microporous membrane obtained by the sequential biaxial stretching method was loaded with an appropriate amount of meta-type wholly aromatic polyfluoreneamine, alumina particles, and dimethylacetamide ( The membrane for non-aqueous secondary batteries having a heat-resistant porous layer formed through the processes of coagulation, water washing and drying in the Meyer rods of the coating solution of DMAc) and tripropylene glycol (TPG).

專利文獻5中，使利用逐次雙軸拉伸法得到之聚乙烯微多孔膜通過適量載有由間位型全芳香族聚醯胺、氫氧化鋁、DMAc及TPG構成之塗佈液之相對之邁耶棒間，經由凝固、水洗及乾燥製程，得到形成有耐熱性多孔質層之非水系二次電池用隔膜。 In Patent Document 5, a relatively small amount of a polyethylene microporous film obtained by a sequential biaxial stretching method is loaded with a coating solution composed of meta-type wholly aromatic polyamine, aluminum hydroxide, DMAc, and TPG. The Meyer rods are obtained through a process of coagulation, water washing and drying to obtain a non-aqueous secondary battery separator having a heat-resistant porous layer formed thereon.

專利文獻6中，使利用逐次雙軸拉伸法得到之聚乙烯微多孔膜通過適量載有由聚間苯二甲醯間苯二胺、氫氧化鋁、DMAc及TPG構成之塗佈液之相對之邁耶棒間，經由凝固、水洗及乾燥製程，得到形成有耐熱性多孔質層之非水系二次電池用隔膜。 In Patent Document 6, the polyethylene microporous film obtained by the sequential biaxial stretching method is allowed to pass a suitable amount of a coating solution composed of polymetaphenylene metaisophenylene diamine, aluminum hydroxide, DMAc, and TPG. In Meyer rods, a non-aqueous secondary battery separator having a heat-resistant porous layer formed is obtained through the processes of coagulation, washing and drying.

專利文獻7中，使用縱向拉伸裝置將具有外層含有β晶型成核劑且含有聚丙烯之層之3層結構之無孔膜狀物沿縱向拉伸，接著使用邁耶棒塗佈含有氧化鋁顆粒及聚乙烯醇之水分散液後，沿橫向拉伸2倍後，進行熱定型/熱鬆弛處理，即將逐次雙軸拉伸法與在線塗佈法組合而得到積層多孔薄膜。 In Patent Document 7, a non-porous film having a three-layer structure having a layer containing a β crystal nucleating agent and a layer containing polypropylene is stretched in the longitudinal direction by using a longitudinal stretching device, followed by coating with a Meyer bar and containing oxidation. After the aluminum particle and polyvinyl alcohol aqueous dispersion are stretched twice in the transverse direction, heat setting / heat relaxation treatment is performed, that is, a sequential biaxial stretching method and an in-line coating method are combined to obtain a laminated porous film.

專利文獻8中，例示出一種利用逐次雙軸拉伸法得到之分離膜，所述逐次雙軸拉伸法使用以下拉伸法：於由4個拉伸輥構成之縱向拉伸機中將被拉伸物與拉伸輥之接觸角度設為固定值以上。 In Patent Document 8, an example of a separation membrane obtained by using a sequential biaxial stretching method is described. The sequential biaxial stretching method uses the following stretching method: it will be used in a longitudinal stretching machine composed of 4 stretching rollers. The contact angle between the stretched object and the stretching roller is set to a fixed value or more.

專利文獻9公開有一種技術，其將添加低熔點聚合物之層與不含低熔點聚合物之層之積層物拉伸而製作出微多孔膜。 Patent Document 9 discloses a technique for producing a microporous film by stretching a laminate of a layer containing a low-melting polymer and a layer containing no low-melting polymer.

[先前技術文獻]     [Prior technical literature]     [專利文獻]     [Patent Literature]    

專利文獻1：日本專利特開2007-273443號公報。 Patent Document 1: Japanese Patent Laid-Open No. 2007-273443.

專利文獻2：日本專利特開2008-186721號公報。 Patent Document 2: Japanese Patent Laid-Open No. 2008-186721.

專利文獻3：日本專利特開2009-026733號公報。 Patent Document 3: Japanese Patent Laid-Open No. 2009-026733.

專利文獻4：日本專利再表2008-149895號公報。 Patent Document 4: Japanese Patent Re-examined Publication No. 2008-149895.

專利文獻5：日本專利特開2010-092882號公報。 Patent Document 5: Japanese Patent Laid-Open No. 2010-092882.

專利文獻6：日本專利特開2009-205955號公報。 Patent Document 6: Japanese Patent Laid-Open No. 2009-205955.

專利文獻7：日本專利特開2012-020437號公報。 Patent Document 7: Japanese Patent Laid-Open No. 2012-020437.

專利文獻8：日本專利特表2013-530261號公報。 Patent Document 8: Japanese Patent Publication No. 2013-530261.

專利文獻9：日本專利特表2012-521914號公報。 Patent Document 9: Japanese Patent Publication No. 2012-521914.

近年來，特別是鋰離子二次電池不僅被用於行動電話、便攜式訊息終端等小型電子設備，其在大型平板電腦、割草機、電動機車、電動汽車、混合動力車、小型船舶等大型設備用途中之發展也備受期待。於預測大型電池將得到普及之情況下，要求鋰離子二次電池之高容量化之同時，還要求其低成本化。並且預測為削減製造成本，電池用隔膜之長尺寸化(長度1000m以上)今後將逐漸得到發展。通過隔膜之長尺寸化，能夠於縱切製程及電池組裝製程中削減電池用隔膜捲繞體之切換時間，能夠降低材料損耗。 In recent years, especially lithium-ion secondary batteries have been used not only in small electronic devices such as mobile phones and portable information terminals, but also in large tablets, lawn mowers, electric vehicles, electric vehicles, hybrid vehicles, and small ships. Developments in use are also highly anticipated. When large-scale batteries are expected to become widespread, high-capacity lithium-ion secondary batteries are required, and at the same time, cost reduction is required. In addition, in order to reduce manufacturing costs, the battery separators will be gradually increased in size (length of 1,000m or more) in the future. By increasing the size of the separator, it is possible to reduce the switching time of the battery separator winding body in the slitting process and the battery assembly process, thereby reducing material loss.

於設置多孔層之電池用隔膜中，如果多孔層相對於長度方向之厚度變動幅度較大，則存在達不到賦予充分功能之厚度之較薄部分。此時，為充分確保多孔層之功能，需要將平均厚度設為所需最低厚度之1.5倍至2倍之厚度，從而導致高成本。此外，隔膜之厚度變厚，從而電極捲繞體之捲繞數減少，亦會導致阻礙電池之高容量化。 In a battery separator provided with a porous layer, if the thickness of the porous layer varies greatly with respect to the longitudinal direction, there is a relatively thin portion that does not provide a thickness sufficient to provide sufficient functions. At this time, in order to fully ensure the function of the porous layer, it is necessary to set the average thickness to 1.5 to 2 times the required minimum thickness, resulting in high costs. In addition, the thickness of the separator is increased, so that the number of windings of the electrode wound body is reduced, which may also impede the increase in capacity of the battery.

進而，電池用隔膜之長尺寸化由於作為捲繞體時之直徑增大而容易產生捲偏，從而亦會對捲繞體之捲繞狀態造成不良影響。隔膜之薄膜化導致捲繞體之捲數進一步增加，該影響變得愈加顯著。 Furthermore, the increase in the size of the battery separator due to the increase in diameter when used as a wound body tends to cause curling, and this also adversely affects the wound state of the wound body. The thinning of the separator leads to a further increase in the number of turns of the wound body, and this effect becomes more significant.

本發明之目標在於獲得一種積層聚烯烴微多孔膜，其切斷特性優異，適用於對多孔層之厚度進行均勻設置，其長度1000m以上，長度方向之F25值之變動幅度係1MPa以下。進而，本發明之目標在於獲得所述積層聚烯烴微多孔膜、以及於其至少單面設置厚度均勻之多孔層且適用於電池高容量化之電池用隔膜。另外，本說明書所提及之厚度均勻之多孔層係指長度方向之多孔層厚度之變動幅度(R)係1.0μm以下。 The object of the present invention is to obtain a laminated polyolefin microporous membrane, which has excellent cutting characteristics and is suitable for uniformly setting the thickness of a porous layer. Its length is 1000 m or more, and the fluctuation range of the F25 value in the length direction is 1 MPa or less. Furthermore, an object of the present invention is to obtain the laminated polyolefin microporous membrane and a battery separator having a porous layer having a uniform thickness provided on at least one side thereof, and which is suitable for increasing the capacity of a battery. In addition, the uniform thickness porous layer mentioned in this specification means that the variation range (R) of the thickness of the porous layer in the longitudinal direction is 1.0 μm or less.

本案發明人鑒於上述課題，不僅對塗層技術深入研究，還追求適合於塗層之積層聚烯烴微多孔膜，從而完成本發明。 In view of the above-mentioned problems, the inventor of the present case not only made in-depth research on coating technology, but also pursued a laminated polyolefin microporous film suitable for coating, thereby completing the present invention.

為解決上述課題，本發明之積層聚烯烴微多孔膜具有以下構成。 To solve the above problems, the laminated polyolefin microporous membrane of the present invention has the following constitution.

(1)一種積層聚烯烴微多孔膜，其長度1000m以上，具有第一聚烯烴微多孔膜與第二聚烯烴微多孔膜，切斷溫度係 128℃至135℃，每20μm厚度從30℃至105℃之氣阻度上升率不足1.5sec/100ccAir/℃，長度方向之F25值之變動幅度係1MPa以下(此處，F25值表示使用拉伸試驗機將試驗片拉伸25%時之荷載值除以試驗片之剖面積得到之值)。 (1) A laminated polyolefin microporous membrane having a length of more than 1000m, having a first polyolefin microporous membrane and a second polyolefin microporous membrane, with a cutting temperature of 128 ° C to 135 ° C and a thickness of 30 ° C to 20 ° m The rate of increase in air resistance at 105 ° C is less than 1.5sec / 100ccAir / ° C, and the fluctuation range of the F25 value in the longitudinal direction is less than 1MPa (here, the F25 value represents the load value when the test piece is stretched by 25% using a tensile tester (Divided by the cross-sectional area of the test piece).

(2)本發明之積層聚烯烴微多孔膜較佳第二聚烯烴微多孔膜含有熔體流動速率係25g/10min至150g/10min而熔點係120℃以上且不足130℃之樹脂。 (2) The laminated polyolefin microporous membrane of the present invention is preferably a second polyolefin microporous membrane containing a resin having a melt flow rate of 25 g / 10 min to 150 g / 10 min and a melting point of 120 ° C or higher and less than 130 ° C.

(3)本發明之積層聚烯烴微多孔膜較佳於至少單面上設置含有水溶性樹脂或水分散性樹脂及耐熱性顆粒且平均厚度T(ave)係1μm至5μm之多孔層。 (3) The laminated polyolefin microporous membrane of the present invention is preferably provided with a porous layer containing a water-soluble resin or a water-dispersible resin and heat-resistant particles on at least one side, and having an average thickness T (ave) of 1 to 5 μm.

(4)本發明之積層聚烯烴微多孔膜較佳多孔層之長度方向之厚度變動幅度(R)係1.0μm以下。 (4) In the laminated polyolefin microporous membrane of the present invention, the thickness variation range (R) of the porous layer in the length direction is preferably 1.0 μm or less.

(5)本發明之積層聚烯烴微多孔膜較佳水溶性樹脂或水分散性樹脂含有選自由聚乙烯醇、丙烯酸系樹脂及聚偏二氟乙烯系樹脂組成的組中之至少一種樹脂。 (5) The laminated polyolefin microporous film of the present invention preferably contains at least one resin selected from the group consisting of a polyvinyl alcohol, an acrylic resin, and a polyvinylidene fluoride resin.

(6)本發明之積層聚烯烴微多孔膜較佳長度係2000m以上。 (6) The laminated polyolefin microporous membrane of the present invention preferably has a length of 2000 m or more.

(7)本發明之積層聚烯烴微多孔膜較佳長度係3000m以上。 (7) The laminated polyolefin microporous membrane of the present invention preferably has a length of 3000 m or more.

為解決上述課題，本發明之於積層聚烯烴微多孔膜上設置多孔層之電池用隔膜之製造方法具有以下構成。 In order to solve the above-mentioned problems, a method for producing a battery separator in which a porous layer is provided on a laminated polyolefin microporous film of the present invention has the following configuration.

(8)一種積層聚烯烴微多孔膜之製造方法，其包括以下製程：(a)於第一聚烯烴組合物中熔融混煉成膜用溶劑而調 製出第一聚烯烴溶液之製程；(b)於第二聚烯烴組合物中熔融混煉成膜用溶劑而調製出第二聚烯烴溶液之製程；(c)從1個模頭中同時擠出所述第一聚烯烴溶液及所述第二聚烯烴溶液並進行冷卻而形成未拉伸膠狀片材之製程；(d)使所述未拉伸膠狀片材通過至少3對縱向拉伸輥組間，使各輥間之圓周速度分階段增大，從而沿縱向拉伸，得到縱向拉伸膠狀片材之製程(此處，將縱向拉伸輥及與其平行相接之用耐熱性橡膠被覆之軋輥設為1對縱向拉伸輥組，該軋輥與縱向拉伸輥相接之壓力係0.05MPa以上0.5MPa以下)；(e)將所述縱向拉伸膠狀片材以夾鉗間距離於拉幅機出口係50mm以下之方式夾住而沿橫向拉伸，得到雙軸拉伸膠狀片材之製程；(f)從所述雙軸拉伸膠狀片材中提取成膜用溶劑並進行乾燥之製程；以及(g)對乾燥後之片材進行熱處理而得到積層聚烯烴微多孔膜之製程。 (8) A method for manufacturing a laminated polyolefin microporous film, which includes the following processes: (a) a process for preparing a first polyolefin solution by melt-kneading a film-forming solvent in a first polyolefin composition; (b) ) A process for preparing a second polyolefin solution by melt-kneading a solvent for film formation in a second polyolefin composition; (c) simultaneously extruding the first polyolefin solution and the first polyolefin solution from a die; A process of forming a diolefin solution and cooling it to form an unstretched gelatinous sheet; (d) passing the unstretched gelatinous sheet through at least three pairs of longitudinally stretched roller groups to make the peripheral speed between the rollers Increase in stages to stretch in the longitudinal direction to obtain a process for longitudinally stretching the gel-like sheet (here, the longitudinal stretching roller and the heat-resistant rubber-coated roller connected in parallel to the longitudinal stretching roller are set as a pair of longitudinal stretching The pressure of the roller group, the roll and the longitudinal stretching roller are in the range of 0.05 MPa to 0.5 MPa); (e) the longitudinally stretched gelatinous sheet is clamped at a distance of 50 mm or less from the tenter exit. The process of sandwiching and stretching in the transverse direction to obtain a biaxially stretched gelatinous sheet; (f) stretching the gelatinous state from the biaxially stretched gelatinous sheet; Film-forming material is extracted with a solvent and drying process; and (g) drying the sheet after the heat treatment process to obtain a laminate of a polyolefin microporous membrane.

(9)本發明之電池用隔膜之製造方法較佳(d)製程之相鄰縱向拉伸輥之圓周速度比分階段地增大。 (9) The method for manufacturing a battery separator of the present invention is preferred. (D) The peripheral speed ratio of adjacent longitudinal stretching rollers in the manufacturing process is increased in stages.

(10)本發明之電池用隔膜之製造方法較佳包括將積層聚烯烴微多孔膜以搬運速度50m/分鐘以上捲繞至捲繞芯上之製程。 (10) The method for producing a battery separator of the present invention preferably includes a process of winding a laminated polyolefin microporous film onto a winding core at a conveying speed of 50 m / min or more.

(11)本發明之電池用隔膜之製造方法較佳包括於積層聚烯烴微多孔膜之至少單面上以使用擺動精度係10μm/Φ 100mm以下之塗佈輥之輥塗佈法塗佈含有水溶性樹脂或水分散性樹脂及耐熱性顆粒之塗佈液，並進行乾燥之製程。 (11) The method for producing a battery separator of the present invention preferably includes coating on a surface of at least one side of the laminated polyolefin microporous film by a roller coating method using a coating roller having a swing accuracy of 10 μm / Φ 100 mm or less, containing a water-soluble solvent. A coating process of a resin or a water-dispersible resin and heat-resistant particles, and a drying process.

(12)本發明之電池用隔膜之製造方法較佳塗佈輥係凹版輥。 (12) The method for producing a battery separator of the present invention is preferably a coating roll of a gravure roll.

根據本發明，可獲得一種積層聚烯烴微多孔膜，其切斷特性優異，適用於對多孔層之厚度進行均勻設置，此外，根據本發明，可獲得一種電池用隔膜，其於聚烯烴微多孔膜上均勻設置多孔層之厚度且適用於電池之高容量化。 According to the present invention, a laminated polyolefin microporous membrane can be obtained, which has excellent cutting characteristics and is suitable for uniformly setting the thickness of the porous layer. In addition, according to the present invention, a battery separator which is microporous in polyolefins can be obtained. The thickness of the porous layer is uniformly provided on the film, which is suitable for increasing the capacity of a battery.

1‧‧‧縱向拉伸輥 1‧‧‧longitudinal stretching roller

2‧‧‧軋輥 2‧‧‧ roll

3‧‧‧刮刀 3‧‧‧ scraper

4‧‧‧未拉伸膠狀片材 4‧‧‧ unstretched gelatinous sheet

5‧‧‧雙軸拉伸片材 5‧‧‧Biaxially stretched sheet

6‧‧‧再縱向拉伸輥 6‧‧‧ longitudinal stretch roller

7‧‧‧再縱向拉伸用軋輥 7‧‧‧ Roll for longitudinal stretching

8‧‧‧積層聚烯烴微多孔膜 8‧‧‧ laminated polyolefin microporous membrane

9‧‧‧塗佈輥 9‧‧‧ coating roller

10‧‧‧塗佈切線 10‧‧‧ Coated Tangent

11‧‧‧支撐輥 11‧‧‧ support roller

12‧‧‧輥位置調節方向 12‧‧‧ roller position adjustment direction

圖1係示出逐次雙軸拉伸中使用之縱向拉伸裝置A之概略圖。 FIG. 1 is a schematic view showing a longitudinal stretching device A used in sequential biaxial stretching.

圖2係示出逐次雙軸拉伸中使用之縱向拉伸裝置B之概略圖。 FIG. 2 is a schematic view showing a longitudinal stretching device B used in sequential biaxial stretching.

圖3係示出逐次雙軸拉伸中使用之縱向拉伸裝置C之概略圖。 FIG. 3 is a schematic view showing a longitudinal stretching device C used in sequential biaxial stretching.

圖4係示出逐次雙軸拉伸中使用之縱向拉伸裝置D之概略圖。 FIG. 4 is a schematic view showing a longitudinal stretching device D used in sequential biaxial stretching.

圖5係示出再拉伸製程中使用之縱向拉伸裝置之示例之概略圖。 Fig. 5 is a schematic view showing an example of a longitudinal stretching device used in a redrawing process.

圖6係示出塗佈裝置之示例之概略圖。 FIG. 6 is a schematic diagram showing an example of a coating apparatus.

本發明之積層聚烯烴微多孔膜長度1000m以上，長度方向之F25值之變動幅度係1MPa以下(此處，F25值表示使用拉伸試驗機將試驗片拉伸25%時之荷載值除以試驗片之剖面積得到之值)。 The laminated polyolefin microporous membrane of the present invention has a length of 1000 m or more, and the fluctuation range of the F25 value in the length direction is 1 MPa or less (here, the F25 value represents the load value when the test piece is stretched by 25% by a tensile tester divided by the test The value obtained from the cross-sectional area of the sheet).

本發明通過將積層聚烯烴微多孔膜之長度方向之F25值之變動幅度設為1MPa以下，從而可實現積層聚烯烴微多孔膜與塗佈輥之切線(以下簡稱為塗佈切線)之接觸壓力相對於積層聚烯烴微多孔膜之長度方向容易變得均勻，且容易將塗佈厚度設置得均勻之優異功效。如果長度方向之F25值之變動幅度超過1MPa，則於縱切製程及塗佈製程之捲繞時微多孔膜之捲繞體之捲繞強度會產生波動，容易發生撓曲及捲偏，捲繞狀態變差。例如，以捲繞至捲繞芯上時之搬運速度係50m/分鐘以上之高速進行加工時變得顯著。 In the present invention, by setting the variation range of the F25 value in the longitudinal direction of the laminated polyolefin microporous film to be 1 MPa or less, the contact pressure between the laminated polyolefin microporous film and the coating roller (hereinafter referred to as the coating tangent line) can be achieved. Compared with the longitudinal direction of the laminated polyolefin microporous film, it is easy to become uniform, and it is easy to set the coating thickness uniformly. If the fluctuation range of the F25 value in the longitudinal direction exceeds 1 MPa, the winding strength of the wound body of the microporous membrane will fluctuate during the winding of the slitting process and the coating process, and it is easy to cause deflection and roll deviation. The state becomes worse. For example, it becomes remarkable when processing is performed at a high speed of 50 m / min or more when the winding speed is wound on a winding core.

1.積層聚烯烴微多孔膜 1. Laminated polyolefin microporous membrane

從切斷特性與強度及滲透性等物性平衡之觀點出發，積層聚烯烴微多孔膜至少具有第一聚烯烴微多孔膜及第二微聚烯烴多孔膜即可。從積層聚烯烴微多孔膜之表裡平衡之觀點出發，更佳為採用第一聚烯烴微多孔膜/第二聚烯烴微多孔膜/第一聚烯烴微多孔膜或者第二聚烯烴微多孔膜/第一聚烯烴微多孔膜/第二聚烯烴微多孔膜之3層構成。第一聚烯烴微多孔膜由第一聚烯烴樹脂組合物形成，第二聚烯烴微 多孔膜由第二聚烯烴樹脂組合物形成。 From the standpoint of physical properties such as cutting characteristics, strength, and permeability, the laminated polyolefin microporous film may include at least a first polyolefin microporous film and a second micropolyolefin porous film. From the viewpoint of balance between the surface and the inside of the laminated polyolefin microporous membrane, it is more preferable to use the first polyolefin microporous membrane / the second polyolefin microporous membrane / the first polyolefin microporous membrane or the second polyolefin microporous membrane. / The first polyolefin microporous membrane / the second polyolefin microporous membrane is composed of three layers. The first polyolefin microporous film is formed of a first polyolefin resin composition, and the second polyolefin microporous film is formed of a second polyolefin resin composition.

[1]第一聚烯烴微多孔膜 [1] The first polyolefin microporous membrane

第一聚烯烴微多孔膜由第一聚烯烴樹脂組合物形成。作為聚烯烴樹脂組合物，較佳為聚乙烯及聚丙烯。此外，可以係單一物質或2種以上不同聚烯烴樹脂之混合物，例如聚乙烯與聚丙烯之混合物，亦可以係不同烯烴之共聚物。從切斷特性之觀點出發，較佳為聚乙烯樹脂。 The first polyolefin microporous film is formed of a first polyolefin resin composition. As the polyolefin resin composition, polyethylene and polypropylene are preferred. In addition, it can be a single substance or a mixture of two or more different polyolefin resins, such as a mixture of polyethylene and polypropylene, or a copolymer of different olefins. From the viewpoint of cutting characteristics, a polyethylene resin is preferred.

第一聚乙烯樹脂組合物將聚乙烯作為主成分，為提高滲透性及穿刺強度，將第一聚乙烯樹脂組合物設為100質量百分比時，聚乙烯之含量較佳為80質量百分比以上，更佳為90質量百分比以上，進一步較佳為100質量百分比。亦可以20質量百分比以下之比例含有聚丙烯。 The first polyethylene resin composition contains polyethylene as a main component. In order to improve the permeability and puncture strength, when the first polyethylene resin composition is set to 100% by mass, the content of polyethylene is preferably 80% by mass or more. It is preferably 90% by mass or more, and more preferably 100% by mass. Polypropylene may be contained in a proportion of 20% by mass or less.

作為聚乙烯之種類，可列舉出密度超過0.94g/cm³之高密度聚乙烯、密度係0.93g/cm³至0.94g/cm³範圍之中密度聚乙烯、密度低於0.93g/cm³之低密度聚乙烯、超高分子量聚乙烯、以及直鏈狀低密度聚乙烯等。較佳為含有超高分子量聚乙烯。使用共擠出法時，因各層之黏度差等導致寬度方向之物性不均勻之控制變得困難，通過含有超高分子量聚乙烯，從而膜整體之分子網絡變得堅固。由此可抑制拉伸製程之不均勻變形導致厚度不均勻，能夠得到物性均勻之微多孔 膜。從強度之觀點出發，進一步較佳為含有高密度聚乙烯及超高分子量聚乙烯。 Examples of the polyethylene include high-density polyethylene having a density exceeding 0.94 g / cm ³ , medium-density polyethylene having a density ranging from 0.93 g / cm ³ to 0.94 g / cm ³ , and density less than 0.93 g / cm ³ Low density polyethylene, ultra high molecular weight polyethylene, and linear low density polyethylene. It is preferable to contain ultra high molecular weight polyethylene. When the coextrusion method is used, it is difficult to control the non-uniform physical properties in the width direction due to the difference in the viscosity of each layer, etc. By containing ultra-high molecular weight polyethylene, the molecular network of the entire film becomes strong. This can prevent uneven deformation in the stretching process from causing uneven thickness, and can obtain a microporous film with uniform physical properties. From the viewpoint of strength, it is more preferable to contain high-density polyethylene and ultra-high molecular weight polyethylene.

超高分子量聚乙烯不僅可以係乙烯之均聚物，亦可以係含有少量其他α-烯烴之共聚物。作為α-烯烴，可列舉出丙烯、丁烯-1、己烯-1、戊烯-1、4-甲基戊烯-1、辛烯、醋酸乙烯酯、甲基丙烯酸甲酯、苯乙烯等。 The ultra-high molecular weight polyethylene can be not only a homopolymer of ethylene, but also a copolymer containing a small amount of other α-olefins. Examples of the α-olefin include propylene, butene-1, hexene-1, pentene-1, 4-methylpentene-1, octene, vinyl acetate, methyl methacrylate, and styrene. .

超高分子量聚乙烯之重量平均分子量(Weight-average Molecular Weight；以下稱為Mw)較佳為1×10⁶以上且不足4×10⁶。如果Mw係上述較佳範圍內，則能夠使細孔及纖維微細化，能夠提高穿刺強度。 The weight-average molecular weight (hereinafter referred to as Mw) of the ultra-high molecular weight polyethylene is preferably 1 × 10 ⁶ or more and less than 4 × 10 ⁶ . When Mw is in the above-mentioned preferable range, pores and fibers can be made fine, and puncture strength can be improved.

高密度聚乙烯之重量平均分子量較佳為1×10⁵以上，更佳為2×10⁵以上。上限值較佳為Mw係8×10⁵，更佳為Mw係7×10⁵。如果Mw係上述較佳範圍內，則能夠兼顧製膜之穩定性與最終得到之穿刺強度。 The weight average molecular weight of the high-density polyethylene is preferably 1 × 10 ⁵ or more, and more preferably 2 × 10 ⁵ or more. The upper limit value is preferably Mw-based 8 × 10 ⁵ , and more preferably Mw-based 7 × 10 ⁵ . If Mw is in the above-mentioned preferable range, the stability of the film formation and the puncture strength finally obtained can be taken into consideration.

從兼顧穿刺強度與氣阻度且抑制氣阻度之波動之觀點出發，將第一微多孔膜之聚乙烯樹脂整體設為100質量百分比時，超高分子量聚乙烯之含量較佳為15質量百分比至45質量百分比，更佳為18質量百分比至40質量百分比。 From the viewpoint of considering both puncture strength and air resistance and suppressing the fluctuation of air resistance, when the entire polyethylene resin of the first microporous membrane is set to 100% by mass, the content of ultra-high molecular weight polyethylene is preferably 15% by mass To 45 mass percent, more preferably 18 to 40 mass percent.

第一聚乙烯樹脂組合物實質上不含低熔點樹脂。「實質上不含低熔點樹脂」係指例如利用交叉分級色譜儀等提取之90℃以下之溶出成分之分率係5.0質量百分比以下。這是因為即使不有目的地添加低熔點樹脂，於高分子中亦會使分子量擁有分佈，因而含有可能導致低熔點之低分子成分，所以難以設為0質量百分比之緣故。如果低熔點樹脂於整層中均存在，則即使處於切斷前，加熱時氣阻度亦容易變差。 The first polyethylene resin composition is substantially free of a low-melting resin. The “substantially low-melting resin” means, for example, that the fraction of the eluted component at 90 ° C. or lower extracted by a cross-grading chromatography or the like is 5.0% by mass or less. This is because even if a low-melting resin is not purposefully added, the molecular weight will have a distribution in the polymer, and therefore it contains a low-molecular component that may cause a low melting point, so it is difficult to set it to 0% by mass. If a low-melting resin is present in the entire layer, even before the cutting, the air resistance is easily deteriorated during heating.

利用交叉分級色譜儀提取之溶出成分例如能夠如下求出。 The eluted component extracted by the cross-class chromatography can be obtained, for example, as follows.

．測定裝置：交叉分級色譜儀CFC2型(Polymer ChAR公司製) ． Measuring device: Cross-classification chromatograph CFC2 (manufactured by Polymer ChAR)

．檢測器：紅外分光光度計IR4型(Polymer ChAR公司製) ． Detector: IR4 spectrophotometer (manufactured by Polymer ChAR)

．檢測波長：3.42μm ． Detection wavelength: 3.42 μm

．色譜柱：昭和電工(株)製「Shodex」(註冊商標)UT806M ． Column: "Shodex" (registered trademark) UT806M, manufactured by Showa Denko Corporation

．色譜柱溫度：140℃ ． Column temperature: 140 ° C

．溶劑(移動相)：鄰二氯苯 ． Solvent (mobile phase): o-dichlorobenzene

．溶劑流速：1.0ml/分鐘 ． Solvent flow rate: 1.0ml / min

．試料濃度：3.0mg/ml ． Sample concentration: 3.0mg / ml

．降溫時間：140分鐘(140℃→0℃) ． Cooling time: 140 minutes (140 ℃ → 0 ℃)

．90℃以下之溶出成分量：將0℃至140℃以每10℃為單位進行劃分，將各提取量內0℃至90℃之重量相加，用得到之重量和除以整體提取量，從而算出90℃以下之溶出成分 量。 ． The amount of dissolved components below 90 ° C: divide 0 ° C to 140 ° C in units of 10 ° C, add the weights of 0 ° C to 90 ° C in each extraction amount, divide the obtained weight by the total extraction amount, and Calculate the amount of eluted components below 90 ° C.

[2]第二聚烯烴微多孔膜 [2] Second polyolefin microporous membrane

第二聚烯烴微多孔膜由第二聚烯烴樹脂組合物形成。第二聚烯烴樹脂組合物只要具有下述特性，亦可以係與第一聚烯烴樹脂組合物同種之聚烯烴樹脂組合物。從強度之觀點出發，第二聚烯烴樹脂組合物較佳含有高密度聚乙烯50質量百分比以上。高密度聚乙烯之重量平均分子量較佳為1×10⁵至8×10⁵，更佳為2×10⁵至7×10⁵。通過設為上述較佳範圍內，能夠兼顧製膜之穩定性與最終得到之穿刺強度。 The second polyolefin microporous film is formed of a second polyolefin resin composition. The second polyolefin resin composition may be the same polyolefin resin composition as the first polyolefin resin composition as long as it has the following characteristics. From the viewpoint of strength, the second polyolefin resin composition preferably contains 50% by mass or more of the high-density polyethylene. The weight average molecular weight of the high-density polyethylene is preferably 1 × 10 ⁵ to 8 × 10 ⁵ , and more preferably 2 × 10 ⁵ to 7 × 10 ⁵ . By setting it as the said preferable range, the stability of film formation and the puncture strength finally obtained can be considered.

為了對第二聚烯烴微多孔膜賦予低溫下之切斷功能，提高作為電池用隔膜之特性，第二聚乙烯樹脂組合物含有低熔點樹脂很重要。低熔點樹脂可列舉出低密度聚乙烯、直鏈狀低密度聚乙烯、乙烯-α-烯烴共聚物等。作為α-烯烴，可列舉出與第一聚乙烯樹脂組合物同樣之α-烯烴。 It is important that the second polyethylene resin composition contains a low-melting resin in order to provide the second polyolefin microporous film with a cutting function at a low temperature and improve the characteristics as a battery separator. Examples of the low-melting resin include low-density polyethylene, linear low-density polyethylene, and an ethylene-α-olefin copolymer. Examples of the α-olefin include the same α-olefin as the first polyethylene resin composition.

低熔點樹脂之熔體流動速率(MFR)係25g/10min以上很重要。更佳為50g/10min以上，進一步較佳為100g/min以上。如果MFR係25g/10min以上，則流動性良好，於拉伸過程中不易產生厚度不均勻，能夠形成均勻之膜厚分佈。此外，分子運動性良好，因此不易留下殘留形變，於低溫下分子充分產生弛豫，因此於低於熔點之溫度不易因殘留形變導 致孔閉塞。因此，於30℃至105℃範圍內，能夠抑制透氣度上升。上限值較佳為150g/min，更佳為140g/min。如果MFR超過150g/min，則熔融物之黏度過低，因此於與第一聚乙烯樹脂組合物之共擠出中，各層可能無法均勻擠出。此外，於製造時之拉伸製程中，黏度較低，因此可能引起微多孔膜之斷裂。 It is important that the melt flow rate (MFR) of the low melting point resin is 25 g / 10 min or more. It is more preferably 50 g / 10 min or more, and still more preferably 100 g / min or more. If the MFR is 25g / 10min or more, the fluidity is good, the thickness unevenness is unlikely to occur during the stretching process, and a uniform film thickness distribution can be formed. In addition, the molecular mobility is good, so it is not easy to leave residual deformation, and the molecules sufficiently relax at low temperature, so it is not easy to cause pore occlusion due to residual deformation at a temperature lower than the melting point. Therefore, in the range of 30 ° C to 105 ° C, an increase in air permeability can be suppressed. The upper limit value is preferably 150 g / min, and more preferably 140 g / min. If the MFR exceeds 150 g / min, the viscosity of the melt is too low, so that during co-extrusion with the first polyethylene resin composition, the layers may not be uniformly extruded. In addition, during the stretching process during manufacture, the viscosity is low, which may cause the microporous film to break.

低熔點樹脂之熔點係120℃以上且不足130℃很重要。熔點不足120℃時，熔點過低，因此利用共擠出法進行積層時，如果將拉伸溫度升高至與含有超高分子量之第一聚乙烯樹脂組合物進行積層時積層體能夠充分拉伸之溫度，則構成第二聚烯烴微多孔膜之樹脂成分熔融而對孔形成造成不良影響，氣阻度可能變差。另一方面，為防止孔閉塞而降低整體之拉伸溫度時，作為積層體整體之軟化變得不充分，通過於A層添加超高分子量，可能無法充分得到所期待之厚度均勻性之功效。另一方面，熔點係130℃以上時，難以達成作為目標之較低切斷溫度。 It is important that the melting point of the low-melting resin is 120 ° C or higher and less than 130 ° C. When the melting point is lower than 120 ° C, the melting point is too low. Therefore, when the lamination is performed by the coextrusion method, if the stretching temperature is increased to the time when the lamination is performed with the first polyethylene resin composition containing an ultrahigh molecular weight, the laminated body can be sufficiently stretched. If the temperature is too high, the resin component constituting the second polyolefin microporous membrane is melted, which adversely affects pore formation, and the degree of air resistance may be deteriorated. On the other hand, when the overall stretching temperature is lowered to prevent pore blocking, the entire layered body is not sufficiently softened. By adding an ultra-high molecular weight to the A layer, the desired effect of thickness uniformity may not be sufficiently obtained. On the other hand, when the melting point is 130 ° C or higher, it is difficult to achieve the target lower cutoff temperature.

將第二聚乙烯樹脂組合物設為100質量百分比時，低熔點樹脂之含量之下限值較佳為20質量百分比至35質量百分比，更佳為25質量百分比至30質量百分比。如果係20質量百分比以上，則能夠將切斷溫度設為128℃至135℃。如果係35質量百分比以下，則黏度較低，能夠抑制於微多孔 膜之製膜時之橫向拉伸時容易發生之斷裂。 When the second polyethylene resin composition is 100% by mass, the lower limit of the content of the low-melting resin is preferably 20% by mass to 35% by mass, and more preferably 25% by mass to 30% by mass. If it is 20% by mass or more, the cut-off temperature can be set to 128 ° C to 135 ° C. If it is 35 mass% or less, the viscosity is low, and it is possible to suppress cracks that are liable to occur during lateral stretching at the time of film formation of the microporous film.

從穿刺強度之觀點出發，第二聚乙烯樹脂組合物較佳為含有超高分子量聚乙烯。超高分子量聚乙烯較佳為與第一聚乙烯樹脂組合物相同。 From the viewpoint of puncture strength, the second polyethylene resin composition preferably contains an ultra-high molecular weight polyethylene. The ultra-high molecular weight polyethylene is preferably the same as the first polyethylene resin composition.

將聚乙烯樹脂整體設為100質量百分比時，第二聚乙烯樹脂組合物之超高分子量聚乙烯之含量之下限值較佳為10質量百分比至40質量百分比，更佳為18質量百分比至30質量百分比。超高分子量聚乙烯樹脂與低熔點樹脂之分子運動性之差較大，因此如果超過40質量百分比，則熔融混煉時容易進行與低熔點樹脂之分離，可能引起最終得到之微多孔膜之外觀不良。 When the entire polyethylene resin is set to 100% by mass, the lower limit of the content of the ultrahigh molecular weight polyethylene of the second polyethylene resin composition is preferably 10% to 40% by mass, and more preferably 18% to 30% by mass. Mass percentage. The difference in molecular mobility between the ultra-high molecular weight polyethylene resin and the low melting point resin is large. Therefore, if it exceeds 40% by mass, it is easy to separate from the low melting point resin during melt-kneading, which may cause the appearance of the finally obtained microporous membrane bad.

第一聚乙烯樹脂組合物及第二聚乙烯樹脂組合物之重量平均分子量(Mw)與數目平均分子量(Number-average Molecular Weight；Mn)之比(Mw/Mn)較佳為5至200範圍內，更佳為10至100。如果Mw/Mn之範圍係上述較佳範圍，則容易將聚乙烯之溶液擠出。此外聚乙烯微多孔膜使厚度薄膜化時，亦可得到充分之機械強度。Mw/Mn作為分子量分佈之尺度使用，例如，採用由單一物質構成之聚乙烯時，該值越大，分子量分佈之範圍越大。由單一物質構成之聚乙烯之Mw/Mn能夠通過聚乙烯之多段聚合來適當調整。此外， 聚乙烯之混合物之Mw/Mn能夠通過對各成分之分子量及混合比例進行調整來適當調整。 The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number-average molecular weight (Mn) of the first polyethylene resin composition and the second polyethylene resin composition is preferably in the range of 5 to 200. , More preferably 10 to 100. If the range of Mw / Mn is the above-mentioned preferable range, it is easy to extrude a solution of polyethylene. In addition, when the thickness of the polyethylene microporous film is reduced, sufficient mechanical strength can also be obtained. Mw / Mn is used as a measure of the molecular weight distribution. For example, when polyethylene composed of a single substance is used, the larger the value, the larger the range of the molecular weight distribution. The Mw / Mn of polyethylene composed of a single substance can be appropriately adjusted by multi-stage polymerization of polyethylene. In addition, the Mw / Mn of the polyethylene mixture can be appropriately adjusted by adjusting the molecular weight and mixing ratio of each component.

本發明之積層聚烯烴微多孔膜於不損害本發明之功效之範圍內，亦可以含有抗氧化劑、熱穩定劑、抗靜電劑、紫外線吸收劑、以及抗黏劑、填充材料等各種添加劑。特別是出於抑制聚烯烴樹脂之熱履歷導致氧化劣化之目的，較佳添加抗氧化劑。適當選擇抗氧化劑、熱穩定劑之種類及添加量對調整或增強微多孔膜之特性而言很重要。 The laminated polyolefin microporous membrane of the present invention may also contain various additives such as antioxidants, heat stabilizers, antistatic agents, ultraviolet absorbers, anti-adhesive agents, and filler materials, so long as the effects of the present invention are not impaired. In particular, for the purpose of suppressing oxidative degradation caused by the thermal history of polyolefin resins, it is preferable to add an antioxidant. Proper selection of the type and amount of antioxidants and heat stabilizers is important for adjusting or enhancing the characteristics of the microporous membrane.

本發明中使用之積層聚烯烴微多孔膜較佳為實質上不含無機顆粒。「實質上不含無機顆粒」係指例如利用螢光X射線分析對無機元素進行定量時較佳為50ppm以下，更佳為10ppm以下，進一步較佳為檢測極限以下之含量。即使未主動向積層聚乙烯微多孔膜中添加顆粒，源自外來異物之污染物成分、原料樹脂或積層聚烯烴微多孔膜之製造製程之生產線及裝置上附著之污漬亦會發生剝離，從而混入膜中，因此可能檢測到50ppm以下之量。 The laminated polyolefin microporous film used in the present invention is preferably substantially free of inorganic particles. The "substantially free of inorganic particles" means, for example, a content of 50 ppm or less, more preferably 10 ppm or less, and even more preferably a detection limit or less when quantifying inorganic elements by fluorescent X-ray analysis. Even if particles are not actively added to the laminated polyethylene microporous membrane, contaminant components derived from foreign substances, raw material resins, or stains attached to the production line and device of the laminated polyolefin microporous membrane manufacturing process will peel off and mix in. In the film, therefore, amounts below 50 ppm may be detected.

本發明之積層聚烯烴微多孔膜之長度方向之F25值之變動幅度係1MPa以下，較佳為0.8MPa以下，更佳為0.6MPa以下，進一步較佳為0.4MPa以下。如下述所示，特別是通過對縱向拉伸製程及橫向拉伸製程進行高級控制，從而能夠 控制積層聚烯烴微多孔膜之長度方向之F25值之變動幅度。 The variation range of the F25 value in the longitudinal direction of the laminated polyolefin microporous membrane of the present invention is 1 MPa or less, preferably 0.8 MPa or less, more preferably 0.6 MPa or less, and still more preferably 0.4 MPa or less. As shown below, especially by advanced control of the longitudinal stretching process and the transverse stretching process, it is possible to control the fluctuation range of the F25 value in the longitudinal direction of the laminated polyolefin microporous membrane.

[3]積層聚烯烴微多孔膜之製造方法 [3] Manufacturing method of laminated polyolefin microporous membrane

積層聚烯烴微多孔膜只要係滿足上述各種特征之範圍內，則能夠自由選擇與目的相應之製造方法。作為微多孔膜之製造方法，有發泡法、相分離法、溶解再結晶法、拉伸開孔法、粉末燒結法等，這些製造方法中出於微細孔之均勻化、成本之方面，較佳為相分離法。 As long as the laminated polyolefin microporous film is within a range satisfying the above-mentioned various characteristics, a manufacturing method corresponding to the purpose can be freely selected. As a method for manufacturing a microporous membrane, there are a foaming method, a phase separation method, a dissolution recrystallization method, a stretch opening method, and a powder sintering method. Among these manufacturing methods, the uniformity of micropores and the cost are relatively low. The phase separation method is preferred.

作為利用相分離法之製造方法，例如可列舉出以下方法：對聚烯烴與成膜用溶劑進行加熱熔融混煉，將得到之聚烯烴樹脂溶液從模頭中擠出並進行冷卻，對得到之膠狀片材沿兩方向進行拉伸，然後，除去成膜溶劑，從而得到積層微多孔膜。 As a manufacturing method using a phase separation method, for example, the following method may be mentioned: polyolefin and a film-forming solvent are heated and melt-kneaded, the obtained polyolefin resin solution is extruded from a die and cooled, and the obtained The gel-like sheet is stretched in both directions, and then the film-forming solvent is removed to obtain a laminated microporous film.

對本發明之積層聚烯烴微多孔膜之製造方法進行詳述。 The manufacturing method of the laminated polyolefin microporous membrane of the present invention is described in detail.

本發明中利用輥法、拉幅法或者這些方法之組合沿長度方向(亦稱為「MD」或「縱向」)及寬度方向(亦稱為「TD」或「橫向」)之兩方向以指定倍率對膠狀片材進行拉伸。本發明中拉伸較佳為依次進行縱向拉伸及橫向拉伸之逐次雙軸拉伸法。同時雙軸拉伸法係使用夾住未拉伸膠狀片材之兩端之夾鉗進行固定後，沿縱向及橫向同時使所述夾鉗擴張之拉伸法。該同時雙軸拉伸法中，隨著拉伸倍率變大，夾鉗之 間隔變寬，長度方向之片材之品質產生波動，結果導致長度方向上F25值之變動幅度可能增大。 In the present invention, the roll method, tenter method, or a combination of these methods is used to specify the two directions of the length direction (also referred to as "MD" or "longitudinal") and the width direction (also referred to as "TD" or "lateral"). The gel sheet is stretched at a magnification. The stretching in the present invention is preferably a sequential biaxial stretching method in which a longitudinal stretching and a transverse stretching are sequentially performed. At the same time, the biaxial stretching method is a stretching method in which the clamps are clamped at both ends of the unstretched gelatinous sheet, and then the clamps are expanded simultaneously in the longitudinal and transverse directions. In this simultaneous biaxial stretching method, as the stretching magnification becomes larger, the interval between the clamps becomes wider, and the quality of the sheet in the longitudinal direction fluctuates, resulting in an increase in the variation range of the F25 value in the longitudinal direction.

本發明之積層聚烯烴微多孔膜之製造方法含有以下(a)至(f)之製程。 The method for producing a laminated polyolefin microporous membrane of the present invention includes the following processes (a) to (f).

(a)於第一聚烯烴組合物中熔融混煉成膜用溶劑而調製出第一聚烯烴溶液之製程。 (a) A process for preparing a first polyolefin solution by melt-kneading a film-forming solvent in a first polyolefin composition.

(b)於第二聚烯烴組合物中熔融混煉成膜用溶劑而調製出第二聚烯烴溶液之製程。 (b) A process for preparing a second polyolefin solution by melt-kneading the solvent for film formation in the second polyolefin composition.

(c)從1個模頭中同時擠出所述第一聚烯烴溶液及所述第二聚烯烴溶液並進行冷卻而形成未拉伸膠狀片材之製程。 (c) a process in which the first polyolefin solution and the second polyolefin solution are simultaneously extruded from a die and cooled to form an unstretched gel-like sheet.

(d)使所述未拉伸膠狀片材通過至少3對縱向拉伸輥組間，利用分階段增大之輥間之圓周速度沿縱向拉伸，得到縱向拉伸膠狀片材之製程(此處，將縱向拉伸輥及與其平行相接之用耐熱性橡膠被覆之軋輥設為1對縱向拉伸輥組，該軋輥與縱向拉伸輥相接之壓力係0.05MPa以上0.5MPa以下)。 (d) the process of passing the unstretched gelatinous sheet through at least three pairs of longitudinal stretch rollers and stretching in the longitudinal direction by using the circumferential speed between the rolls that is increased in stages to obtain a longitudinally stretched gelatinous sheet (Here, the longitudinal stretching roll and the heat-resistant rubber-covered rolls connected in parallel to the longitudinal stretching roll are set as a pair of longitudinal stretching rolls. The pressure at which the roll is in contact with the longitudinal stretching roll is 0.05 MPa to 0.5 MPa. ).

(e)將所述縱向拉伸膠狀片材以夾鉗間距離於拉幅機出口係50mm以下之方式夾住而沿橫向拉伸，得到雙軸拉伸膠狀片材之製程。 (e) The longitudinal stretching of the gelatinous sheet is clamped in a manner that the distance between the clamps is 50 mm or less from the tenter exit and stretched in the transverse direction to obtain a biaxially stretched gelatinous sheet.

(f)從所述雙軸拉伸膠狀片材中提取成膜用溶劑並進行乾燥之製程。 (f) a process of extracting a film-forming solvent from the biaxially stretched gelatinous sheet and drying it.

進而，於(a)至(f)之製程後，亦可以根據需要設置電暈處理製程等。 Furthermore, after the processes of (a) to (f), a corona treatment process or the like may be set as required.

下面以使用聚乙烯樹脂作為聚烯烴樹脂之示例對各製程進行說明。 Hereinafter, each process will be described using an example of using a polyethylene resin as the polyolefin resin.

(a)第一聚烯烴樹脂溶液之調製製程 (a) Preparation process of the first polyolefin resin solution

作為第一聚烯烴樹脂溶液之調製製程，於第一聚烯烴樹脂組合物中添加成膜用溶劑後，進行熔融混煉，調製出聚烯烴樹脂溶液。作為熔融混煉方法，例如能夠利用使用日本專利特公平06-104736號公報及日本國專利特許第3347835號公報中記載之雙軸擠出機之方法。熔融混煉方法眾所周知，因此省略說明。 As a preparation process of the first polyolefin resin solution, a film-forming solvent is added to the first polyolefin resin composition, and then melt-kneaded to prepare a polyolefin resin solution. As the melt-kneading method, for example, a method using a biaxial extruder described in Japanese Patent Laid-Open No. 06-104736 and Japanese Patent Laid-Open No. 3347835 can be used. Since a melt-kneading method is well known, description is abbreviate | omitted.

作為成膜用溶劑，只要能夠充分溶解聚乙烯，則並無特別限定。例如，可列舉出壬烷、癸烷、十一烷、十二烷、液體石蠟等脂肪族或環脂肪族之烴、或者沸點與該烴對應之礦物油餾出物等，較佳為液體石蠟等不揮發性之溶劑。 The film-forming solvent is not particularly limited as long as it can sufficiently dissolve polyethylene. Examples include aliphatic or cycloaliphatic hydrocarbons such as nonane, decane, undecane, dodecane, and liquid paraffin, or mineral oil distillates having boiling points corresponding to the hydrocarbons, and the like is preferably liquid paraffin. And other non-volatile solvents.

將聚乙烯樹脂與成膜用溶劑之合計設為100重量份時，第一聚烯烴樹脂溶液中之聚乙烯樹脂濃度較佳為25重量份至40重量份。如果聚乙烯樹脂濃度係上述較佳範圍內，則將聚乙烯樹脂溶液擠出時能夠於模頭出口防止膨脹及頸縮，可維持膠狀片材之成型性及自我支撐性。 When the total of the polyethylene resin and the film-forming solvent is 100 parts by weight, the polyethylene resin concentration in the first polyolefin resin solution is preferably 25 to 40 parts by weight. If the polyethylene resin concentration is within the above-mentioned preferred range, it can prevent swelling and necking at the die exit when the polyethylene resin solution is extruded, and can maintain the moldability and self-supporting properties of the gel-like sheet.

(b)第二聚烯烴樹脂溶液之調製製程 (b) Preparation process of the second polyolefin resin solution

第二聚烯烴樹脂溶液之調製製程除了使用第二聚烯烴樹脂組合物以外，可以與第一聚烯烴樹脂溶液之調製製程相同。 The preparation process of the second polyolefin resin solution may be the same as the preparation process of the first polyolefin resin solution except that the second polyolefin resin composition is used.

(c)成型未拉伸膠狀片材之製程 (c) Process for forming unstretched gel sheet

作為成型未拉伸膠狀片材之製程，將聚乙烯樹脂溶液從擠出機中直接或者經由其他擠出機送給模頭，擠出成片狀，進行冷卻，而成型未拉伸膠狀片材。亦可將相同或不同組成之複數個聚烯烴溶液從擠出機送給一個模頭，於此處層壓成層狀，並擠出成片狀。 As a process for forming an unstretched gelatinous sheet, a polyethylene resin solution is sent from an extruder directly or through another extruder to a die, extruded into a sheet shape, and cooled to form an unstretched gelled Sheet. It is also possible to feed a plurality of polyolefin solutions of the same or different composition from an extruder to a die, where they are laminated into a layer and extruded into a sheet.

擠出方法可以係平模法及吹塑法之任意一種。擠出溫度較佳為140℃至250℃，擠出速度較佳為0.2m/分鐘至15m/分鐘。通過調節聚烯烴溶液之各擠出量，從而能夠調節膜厚。作為擠出方法，例如能夠利用日本專利特公平06-104736號公報及日本國專利特許第3347835號公報中公開之方法。 The extrusion method may be either a flat die method or a blow molding method. The extrusion temperature is preferably 140 ° C to 250 ° C, and the extrusion speed is preferably 0.2 m / minute to 15 m / minute. By adjusting each extrusion amount of the polyolefin solution, the film thickness can be adjusted. As the extrusion method, for example, the methods disclosed in Japanese Patent Publication No. 06-104736 and Japanese Patent Publication No. 3347835 can be used.

通過對被擠出成片狀之聚乙烯樹脂溶液進行冷卻，從而形成膠狀片材。作為冷卻方法，能夠使用與冷風、冷卻水等冷媒接觸之方法、以及與冷卻輥接觸之方法等，較佳為與經過冷媒冷卻後之輥接觸並進行冷卻。例如，通過使被擠出成片狀之聚乙烯樹脂溶液與用冷媒將表面溫度設定為20℃至40℃且旋轉之冷卻輥接觸，從而能夠形成未拉伸膠狀片材。 被擠出之聚乙烯樹脂溶液較佳為冷卻至25℃以下。 The polyethylene resin solution extruded into a sheet is cooled to form a gel sheet. As the cooling method, a method of contacting with a cooling medium such as cold air and cooling water, a method of contacting with a cooling roller, and the like can be used, and it is preferable to contact and cool the roller after cooling with the refrigerant. For example, an unstretched gelatinous sheet can be formed by bringing a polyethylene resin solution extruded into a sheet into contact with a cooling roll whose surface temperature is set to 20 ° C to 40 ° C with a refrigerant and rotating. The extruded polyethylene resin solution is preferably cooled to 25 ° C or lower.

(d)縱向拉伸製程 (d) Longitudinal stretching process

作為縱向拉伸製程，使未拉伸膠狀片材經由複數根預熱輥，升溫至指定溫度後，使其通過各輥間之圓周速度分階段增大之至少3對縱向拉伸輥組，並沿縱向拉伸，得到縱向拉伸膠狀片材。 As a longitudinal stretching process, the unstretched gelatinous sheet is passed through a plurality of preheating rollers, and after heating up to a specified temperature, it is passed through at least three pairs of longitudinal stretching roller groups in which the peripheral speed between the rollers is gradually increased. And stretched in the longitudinal direction to obtain a longitudinally stretched gelatinous sheet.

本發明中抑制縱向拉伸之片材滑動，進行均勻之縱向拉伸，於控制長度方向之F25值方面很重要。 In the present invention, it is important to control the F25 value in the longitudinal direction to suppress the sliding of the longitudinally stretched sheet and perform uniform longitudinal stretching.

於拉伸製程中，將縱向拉伸輥及與縱向拉伸輥平行且以恆定壓力相接之軋輥設為1對輥組，通過使未拉伸膠狀片材通過至少3對輥組間，從而利用輥間之圓周速度比進行縱向拉伸。通過與縱向拉伸輥平行地配置軋輥，使片材黏附於縱向拉伸輥上，通過固定片材之拉伸位置，使片材穩定行進，能夠進行均勻之縱向拉伸。此外，為進行均勻之縱向拉伸，縱向拉伸製程相較於1段拉伸，較佳為分成2段拉伸以上來設為所需要之拉伸倍率。亦即，配置3對以上縱向拉伸輥很重要。 In the stretching process, a longitudinal stretching roll and a roll parallel to the longitudinal stretching roll and contacted with a constant pressure are set as a pair of roll groups. By passing an unstretched gel-like sheet between at least 3 pairs of roll groups, Thereby, longitudinal stretching is performed using the peripheral speed ratio between the rolls. By arranging the rolls in parallel with the longitudinal stretching rolls, the sheet is adhered to the longitudinal stretching rolls. By fixing the stretching position of the sheet, the sheet can stably travel, and uniform longitudinal stretching can be performed. In addition, in order to perform uniform longitudinal stretching, the longitudinal stretching process is preferably divided into two or more stretches to set the required stretching ratio, as compared to one stretch. That is, it is important to arrange 3 or more pairs of longitudinal stretching rolls.

本發明中，通過將各拉伸輥間之圓周速度分階段增大，而將未拉伸膠狀片材沿長度方向進行拉伸很重要。進而，較 佳亦使相鄰拉伸輥之圓周速度比分階段增大。亦即，將第1根拉伸輥與第2根拉伸輥之圓周速度比設置得較小，並按第2根拉伸輥與第3根拉伸輥之圓周速度比、第3根拉伸輥與第4根拉伸輥之圓周速度比之順序依次使圓周速度比增大，從而可控制長度方向之F25之變動幅度，並能夠兼顧生產效率。這是因為未拉伸膠狀成型片材通過第1根拉伸輥時，含有較多成膜用溶劑而容易滑動，但通過將各拉伸輥間之圓周速度分階段增大，而容易得到成膜用溶劑之擠出功效，能夠防止縱向拉伸製程之滑動之緣故。此處，擠出功效係指通過從未拉伸膠狀片材或縱向拉伸中之膠狀片材中擠出成膜用溶劑，從而能夠抑制與縱向拉伸輥之滑動並穩定地拉伸。 In the present invention, it is important to stretch the unstretched gel-like sheet in the longitudinal direction by increasing the peripheral speed between the stretching rolls in stages. Further, it is preferable that the peripheral speed ratio of adjacent stretching rolls is increased in stages. That is, the peripheral speed ratio of the first stretching roller and the second stretching roller is set to be small, and the third stretching roller is set according to the circumferential speed ratio of the second stretching roller and the third stretching roller. The order of the peripheral speed ratio of the stretching roller and the fourth stretching roller sequentially increases the peripheral speed ratio, so that the fluctuation range of F25 in the length direction can be controlled, and production efficiency can be taken into consideration. This is because when the unstretched gel-formed sheet passes through the first stretching roll, it contains a large amount of a film-forming solvent and easily slides, but it is easy to obtain by increasing the peripheral speed between the stretching rolls in stages. The extrusion effect of the film-forming solvent can prevent the sliding of the longitudinal stretching process. Here, the extruding effect means that a film-forming solvent can be extruded from an unstretched gel sheet or a gel sheet in longitudinal stretching, so that it can be prevented from sliding with the longitudinal stretching roller and stretched stably. .

第1段拉伸製程之拉伸輥之圓周速度比之上限較佳為1.5以下，更佳為1.3以下，進一步較佳為1.2以下。下限較佳為1.1。此外，相鄰各拉伸輥之圓周速度比之差係0.5以下，較佳為0.4以下，進一步較佳為0.3以下。 The upper limit of the peripheral speed ratio of the stretching roller in the first stage stretching process is preferably 1.5 or less, more preferably 1.3 or less, and still more preferably 1.2 or less. The lower limit is preferably 1.1. The difference between the peripheral speed ratios of adjacent stretching rolls is 0.5 or less, preferably 0.4 or less, and even more preferably 0.3 or less.

相鄰拉伸輥之間隔較佳為將拉伸中之膠狀成型片材從離開拉伸輥到與下個拉伸輥相接之距離設為150mm至500mm之範圍。如果相鄰拉伸輥之間隔不足150mm，則F25之變動幅度可能變大。如果超過500mm，則會妨礙拉伸中之膠狀成型片材之溫度降低，可能產生拉伸不均勻。 The interval between the adjacent stretching rolls is preferably such that the distance from the exit of the stretching gel roll to the contact with the next stretching roll is 150 mm to 500 mm. If the distance between adjacent stretching rolls is less than 150 mm, the fluctuation range of F25 may become larger. If it exceeds 500 mm, the temperature of the gel-formed sheet during stretching will be prevented from decreasing, and stretching unevenness may occur.

縱向拉伸製程之片材之溫度較佳為聚烯烴樹脂之熔點+10℃以下。此外，從積層聚烯烴微多孔膜之彈性、強度之觀點出發，拉伸倍率按面倍率計算較佳為9倍以上，更佳為16倍至400倍。 The temperature of the sheet in the longitudinal stretching process is preferably the melting point of the polyolefin resin + 10 ° C or lower. In addition, from the viewpoint of the elasticity and strength of the laminated polyolefin microporous film, the draw ratio is preferably 9 times or more, and more preferably 16 times to 400 times in terms of area ratio.

關於縱向拉伸輥之表面溫度，按各輥於拉伸輥之有效寬度(拉伸中之片材通過之寬度)中將表面溫度之變動幅度控制於±2℃以內。縱向拉伸輥之表面溫度例如能夠使用紅外放射溫度計進行測定。 Regarding the surface temperature of the longitudinal stretching roll, the fluctuation range of the surface temperature should be controlled within ± 2 ° C according to the effective width of each stretching roll (the width of the sheet passing during stretching). The surface temperature of the longitudinal stretching roll can be measured using, for example, an infrared radiation thermometer.

縱向拉伸輥較佳為表面粗糙度0.3S至5.0S之實施硬鉻電鍍之金屬輥。如果表面粗糙度係該範圍，則熱傳導亦良好，能夠利用與軋輥之協同效應有效地抑制片材滑動。 The longitudinal stretching roll is preferably a metal roll having a surface roughness of 0.3S to 5.0S and subjected to hard chrome plating. When the surface roughness is within this range, heat conduction is also good, and it is possible to effectively suppress sheet slip by utilizing a synergistic effect with a roll.

本發明中，使用軋輥抑制縱向拉伸製程之膠狀片材之滑動。不使用軋輥而僅增大縱向拉伸輥與膠狀片材之接觸面積，無法得到充分之滑動抑制功效，F25值之變動幅度可能增大。此外，如果要用1根軋輥抑制片材之滑動，則需要提高軋輥與拉伸輥相接之壓力(亦稱為夾持壓)，可能損壞得到之積層聚烯烴微多孔膜之細孔。因此，軋輥使用3根以上，將對各軋輥之成對之縱向拉伸輥之夾持壓設置得相對較小很重要。對1根縱向拉伸輥可以使用複數根軋輥。 In the present invention, a roll is used to suppress slippage of the gel-like sheet in the longitudinal stretching process. Without using a roller, only increasing the contact area between the longitudinal stretching roller and the gelatinous sheet, it is not possible to obtain a sufficient sliding suppression effect, and the fluctuation range of the F25 value may increase. In addition, if one roll is to be used to suppress the slippage of the sheet, it is necessary to increase the pressure (also referred to as the nip pressure) at which the roll is in contact with the stretching roll, which may damage the pores of the obtained laminated polyolefin microporous membrane. Therefore, if three or more rolls are used, it is important to set the clamping pressure of the longitudinal stretching rolls of each pair of rolls relatively small. A plurality of rolls can be used for one longitudinal stretching roll.

各軋輥之夾持壓係0.05MPa以上0.5Mpa以下。如果軋輥之夾持壓超過0.5MPa，則得到之積層聚烯烴微多孔膜之細孔可能損壞。如果不足0.05MPa，則夾持壓不充分，無法得到滑動抑制功效，此外，亦不易得到成膜用溶劑之擠出功效。軋輥之夾持壓之下限較佳為0.1MPa，更佳為0.2MPa，上限較佳為0.5MPa，更佳為0.4MPa。如果軋輥之夾持壓係上述範圍內，則可得到適度滑動抑制功效。 The clamping pressure of each roll is 0.05 MPa to 0.5 MPa. If the nip pressure of the roll exceeds 0.5 MPa, the pores of the obtained laminated polyolefin microporous membrane may be damaged. If it is less than 0.05 MPa, the clamping pressure is insufficient, and the slip-inhibiting effect cannot be obtained. In addition, it is difficult to obtain the extrusion effect of the film-forming solvent. The lower limit of the clamping pressure of the roll is preferably 0.1 MPa, more preferably 0.2 MPa, and the upper limit is preferably 0.5 MPa, and more preferably 0.4 MPa. If the nip pressure of the roll is within the above range, a moderate slip suppression effect can be obtained.

此外，軋輥需要用耐熱性橡膠被覆。縱向拉伸製程中，因熱量及張力產生之壓力而導致成膜用溶劑從膠狀片材中滲出，特別是剛擠出後之縱向拉伸製程中之滲出顯著。在滲出之成膜用溶劑介於片材與輥表面之邊界之狀態下，進行片材之搬運及拉伸時，片材呈容易滑動之狀態。藉由將用耐熱性橡膠被覆之軋輥以與縱向拉伸輥平行相接之方式配置，然後使未拉伸膠狀片材通過，能夠從拉伸中之膠狀片材中擠出成膜用溶劑並對其進行拉伸，由此能夠抑制滑動。 The rolls need to be covered with heat-resistant rubber. In the longitudinal stretching process, the film-forming solvent oozes out of the gelatinous sheet due to the pressure caused by heat and tension, especially in the longitudinal stretching process immediately after extrusion. In the state where the exuding film-forming solvent is interposed between the sheet and the surface of the roller, the sheet is in a state of being easily slipped when the sheet is transported and stretched. The rolls covered with heat-resistant rubber are arranged so as to be in contact with the longitudinal stretching rolls in parallel, and then the unstretched gel-like sheet is passed therethrough, and the film can be extruded from the stretched gel-like sheet into a film. It is possible to suppress slippage by stretching the solvent.

軋輥較佳為於直徑100mm至300mm之金屬輥上用厚度3mm至20mm之耐熱性橡膠被覆之輥。耐熱性橡膠部分之體積佔80%以上之所謂橡膠輥中，容易撓曲，對寬度方向不易施加均勻壓力，因此不較佳。 The roll is preferably a roll coated with a heat-resistant rubber having a thickness of 3 mm to 20 mm on a metal roll having a diameter of 100 mm to 300 mm. In a so-called rubber roller in which the volume of the heat-resistant rubber portion occupies more than 80%, it is easy to deflect and it is difficult to apply uniform pressure to the width direction.

於縱向拉伸製程中，如果同時使用將縱向拉伸輥及軋輥上附著之成膜用溶劑去除之方法(亦稱為刮除單元)，則可更加有效地得到滑動抑制功效。刮除單元並無特別限定，能夠使用刮刀、壓縮空氣吹掃、吸引之方法或者將這些方法組合使用。特別是使用刮刀進行刮落之方法相對較容易實施，因此較佳。較佳為以下方法：將刮刀以與縱向拉伸輥之寬度方向平行之方式壓於縱向拉伸輥上，進行刮落，直至從剛通過刮刀後至與拉伸中之膠狀片材相接之拉伸輥表面上看不到成膜用溶劑。刮刀可以使用1片，亦可以使用複數片。此外，刮除單元可以設置於縱向拉伸輥或軋輥之任意一個，或者亦可以設置於兩者。 In the longitudinal stretching process, if the method for removing the film-forming solvent attached to the longitudinal stretching roll and the roll (also referred to as a scraping unit) is used at the same time, the slip suppression effect can be more effectively obtained. The scraping unit is not particularly limited, and a method such as scraper, compressed air purging, and suction can be used or a combination of these methods can be used. In particular, the method of scraping off using a scraper is relatively easy to implement and is therefore preferred. The following method is preferred: the blade is pressed on the longitudinal stretching roller in a manner parallel to the width direction of the longitudinal stretching roller, and scraped off, until the blade just passes through the blade and is in contact with the gel-like sheet during stretching. No film-forming solvent was seen on the surface of the stretching roll. The scraper can be used with one piece or multiple pieces. In addition, the scraping unit may be provided in either one of the longitudinal stretching rolls or the rolls, or may be provided in both.

刮刀之材質只要對成膜用溶劑具有耐性，則並無特別限定，相較於金屬製，較佳為假設刮刀之切屑混入積層聚烯烴微多孔膜亦不會對電氣方面造成不良影響之樹脂製或橡膠製。採用金屬製時，可能對拉伸輥造成劃痕。作為樹脂製刮刀，可列舉出聚酯製、聚縮醛製、聚乙烯製等。 The material of the doctor blade is not particularly limited as long as it is resistant to the film-forming solvent. Compared to metal, it is preferable to make resin blades that do not adversely affect the electrical side, provided that the blades of the doctor blade are mixed into the laminated polyolefin microporous film Or rubber. When it is made of metal, it may scratch the stretching roller. Examples of the resin blade include polyester, polyacetal, and polyethylene.

(e)橫向拉伸製程 (e) Horizontal stretching process

作為橫向拉伸製程，使用夾鉗將縱向拉伸膠狀片材之兩端固定後，於拉幅機內使所述夾鉗沿橫向擴張，將縱向拉伸膠狀片材沿橫向拉伸，得到雙軸拉伸膠狀片材。此處片材行進方向之夾鉗間距離較佳為從拉幅機入口至出口維持在 50mm以下，更佳為25mm以下，進一步較佳為10mm以下。此外，夾鉗間距離較佳為於上述範圍內恆定。如果夾鉗間距離處於上述較佳範圍內，則能夠抑制寬度方向之F25值之變動幅度。 As a transverse stretching process, after the two ends of the longitudinally stretched gelatinous sheet are fixed with clamps, the clamps are expanded in the transverse direction in a tenter, and the longitudinally stretched gelatinous sheet is stretched in the transverse direction. A biaxially stretched gelatinous sheet was obtained. Here, the distance between the clamps in the sheet traveling direction is preferably maintained below 50 mm from the tenter entrance to the exit, more preferably below 25 mm, and even more preferably below 10 mm. The distance between the clamps is preferably constant within the above range. If the distance between the clamps is within the above-mentioned preferred range, the fluctuation range of the F25 value in the width direction can be suppressed.

於橫向拉伸製程或熱處理製程中為抑制劇烈溫度變化之影響，較佳為將拉幅機內分割為10個至30個區域，於各區域獨立進行溫度控制。特別是於熱處理製程之設定為最高溫度之區域中，較佳為使各區域之溫度相對於片材行進方向利用熱風分階段升溫，以防於熱處理製程之各區域間引起劇烈溫度變化。 In order to suppress the influence of drastic temperature changes in the transverse stretching process or heat treatment process, it is preferable to divide the inside of the tenter into 10 to 30 regions, and independently perform temperature control in each region. Especially in the region where the heat treatment process is set to the highest temperature, it is preferable to increase the temperature of each region with hot air in stages relative to the direction of travel of the sheet, so as to prevent rapid temperature changes between the regions of the heat treatment process.

(f)從所述雙軸拉伸膠狀片材中除去成膜用溶劑並進行乾燥之製程 (f) a process of removing the film-forming solvent from the biaxially stretched gelatinous sheet and drying it

使用除去清洗溶劑，從所述雙軸拉伸膠狀片材中將成膜用溶劑除去(清洗)。作為清洗溶劑，能夠使用戊烷、己烷、庚烷等烴；二氯甲烷、四氯化碳等氯化烴；三氟乙烷等氟化烴；以及二***、二氧六環等醚類等易揮發性物質。這些清洗溶劑根據用於聚乙烯之溶解之成膜用溶劑適當選擇，可單獨或混合使用。清洗方法能夠採用以下方法進行，即浸漬於清洗溶劑中提取之方法、噴淋清洗溶劑之方法、從片材之背面側吸引清洗溶劑之方法、或者將這些方法組合之方法等。上述清洗進行至片材之殘留溶劑不足1重量百分比。然後， 對片材進行乾燥，乾燥方法能夠利用加熱乾燥、風乾等方法進行。 The solvent for film formation is removed (washed) from the biaxially stretched gelatinous sheet using a removal cleaning solvent. As the cleaning solvent, hydrocarbons such as pentane, hexane, and heptane; chlorinated hydrocarbons such as methylene chloride and carbon tetrachloride; fluorinated hydrocarbons such as trifluoroethane; and ethers such as diethyl ether and dioxane And other volatile substances. These cleaning solvents are appropriately selected depending on the film-forming solvent used for the dissolution of polyethylene, and they can be used alone or in combination. The cleaning method can be performed by a method of extraction by immersion in a cleaning solvent, a method of spraying the cleaning solvent, a method of sucking the cleaning solvent from the back side of the sheet, or a method of combining these methods. The above cleaning is performed until the residual solvent of the sheet is less than 1% by weight. Then, the sheet is dried, and the drying method can be performed by a method such as heat drying and air drying.

(g)對所述乾燥後之片材進行熱處理而得到積層聚烯烴微多孔膜之製程 (g) a process of heat-treating the dried sheet to obtain a laminated polyolefin microporous membrane

對乾燥後之片材進行熱處理而得到積層聚烯烴微多孔膜。從熱收縮率及氣阻度之觀點出發，熱處理較佳為以90℃至150℃之範圍內之溫度進行。熱處理製程之滯留時間並無特別限定，通常較佳為1秒鐘以上10分鐘以下，更佳為3秒鐘以上2分鐘以下。熱處理能夠採用拉幅機方式、輥方式、壓軋方式、自由方式之任意一種。 The dried sheet is heat-treated to obtain a laminated polyolefin microporous film. From the viewpoint of thermal shrinkage and air resistance, the heat treatment is preferably performed at a temperature in a range of 90 ° C to 150 ° C. The residence time in the heat treatment process is not particularly limited, but it is usually preferably from 1 second to 10 minutes, and more preferably from 3 seconds to 2 minutes. The heat treatment can be performed by any of a tenter method, a roll method, a press method, and a free method.

熱處理製程中較佳為於長度方向及寬度方向之兩方向進行固定，同時沿長度方向及寬度方向之至少一方向收縮。通過熱處理製程能夠將積層聚烯烴微多孔膜之殘留形變除去。從熱收縮率及氣阻度之觀點出發，熱處理製程之長度方向或寬度方向之收縮率較佳為0.01%至50%，更佳為3%至20%。進而，為提高機械強度，可以進行再加熱及再拉伸。再拉伸製程可以採用拉伸輥式或拉幅機式之任意一種。另外，於(a)至(f)之製程後，根據需要亦可以設置電暈處理製程及親水化製程等功能賦予製程。 In the heat treatment process, it is preferable to fix in two directions of the longitudinal direction and the width direction, and at the same time shrink in at least one of the longitudinal direction and the width direction. The residual deformation of the laminated polyolefin microporous membrane can be removed by a heat treatment process. From the viewpoint of thermal shrinkage and air resistance, the shrinkage in the lengthwise or widthwise direction of the heat treatment process is preferably 0.01% to 50%, and more preferably 3% to 20%. Furthermore, in order to improve mechanical strength, reheating and redrawing may be performed. The re-stretching process may use either a stretching roll type or a tenter type. In addition, after the processes of (a) to (f), a function-imparting process such as a corona treatment process and a hydrophilization process can also be set as required.

如上述所示，通過對縱向拉伸及橫向拉伸進行高級控 制，從而能夠減小積層聚烯烴微多孔膜之長度方向之F25值之變動幅度。由此，於後述多孔層之積層製程中，不僅容易減小塗佈厚度之變動幅度，亦可得到捲繞狀態良好之電池用隔膜捲繞體。進而，通過將F25值之變動幅度設為1MPa以下，從而例如於利用複捲機進行捲繞時之以搬運速度超過50m/分鐘之高速進行加工時，亦能夠抑制縱切製程及塗佈製程之搬運中之彎曲。 As shown above, by performing advanced control of the longitudinal stretching and the transverse stretching, it is possible to reduce the fluctuation range of the F25 value in the longitudinal direction of the laminated polyolefin microporous membrane. Therefore, in the lamination process of the porous layer described later, it is not only easy to reduce the fluctuation range of the coating thickness, but also to obtain a battery separator wound body having a good winding state. Furthermore, by setting the fluctuation range of the F25 value to 1 MPa or less, for example, when processing at a high speed of more than 50 m / min when winding by a rewinding machine, the slitting process and the coating process can be suppressed. Bending during transportation.

積層聚烯烴微多孔膜之寬度並無特別限制，下限較佳為500mm，更佳為600mm，進一步較佳為1000mm，上限較佳為4000mm，更佳為3000mm，進一步較佳為2000mm。如果積層聚烯烴微多孔膜之厚度係上述範圍，則適用於高容量電池製作，不易因自重而產生撓曲。 The width of the laminated polyolefin microporous membrane is not particularly limited. The lower limit is preferably 500 mm, more preferably 600 mm, further preferably 1000 mm, the upper limit is preferably 4000 mm, more preferably 3000 mm, and even more preferably 2000 mm. If the thickness of the laminated polyolefin microporous film is in the above range, it is suitable for the production of high-capacity batteries, and it is not easy to cause deflection due to its own weight.

積層聚烯烴微多孔膜之長度之下限較佳為1000m，更佳為2000m，進一步較佳為3000m。上限並無特殊規定，較佳為10000m，更佳為8000m，進一步較佳為7000m。如果積層聚烯烴微多孔膜之長度係上述範圍，則可提高生產效率，作為捲繞體時不易因自重而產生撓曲。 The lower limit of the length of the laminated polyolefin microporous membrane is preferably 1000 m, more preferably 2000 m, and still more preferably 3000 m. The upper limit is not particularly limited, but it is preferably 10,000 m, more preferably 8000 m, and even more preferably 7000 m. If the length of the laminated polyolefin microporous film is within the above range, the production efficiency can be improved, and when it is used as a rolled body, it is unlikely to be deflected due to its own weight.

從電池之高容量化之觀點出發，積層聚烯烴微多孔膜之厚度較佳為5μm至25μm。 From the viewpoint of increasing the capacity of the battery, the thickness of the laminated polyolefin microporous film is preferably 5 μm to 25 μm.

積層聚烯烴微多孔膜之氣阻度較佳為50sec/100ccAir至300sec/100ccAir。 The air-blocking degree of the laminated polyolefin microporous membrane is preferably 50sec / 100ccAir to 300sec / 100ccAir.

積層聚烯烴微多孔膜之空孔率較佳為30%至70%。 The porosity of the laminated polyolefin microporous membrane is preferably 30% to 70%.

從孔閉塞性能之觀點出發，積層聚烯烴微多孔膜之平均孔徑較佳為0.01μm至1.0μm。 From the viewpoint of pore blocking performance, the average pore diameter of the laminated polyolefin microporous membrane is preferably from 0.01 μm to 1.0 μm.

2.多孔層 2. Porous layer

接著，對多孔層進行說明。 Next, the porous layer will be described.

本發明所提及之多孔層可賦予耐熱性、與電極材料之黏附性、電解液滲透性等功能之至少一個，或者使這些功能提高。多孔層由無機顆粒及黏合劑構成。 The porous layer mentioned in the present invention can impart at least one of functions such as heat resistance, adhesion to electrode materials, and electrolyte permeability, or improve these functions. The porous layer is composed of inorganic particles and a binder.

黏合劑具有賦予或提高所述功能並使無機顆粒彼此間結合之作用、以及使積層聚烯烴微多孔膜與多孔層結合之作用。作為黏合劑，可列舉出聚乙烯醇、纖維素醚系樹脂、丙烯酸系樹脂等。作為纖維素醚系樹脂，可列舉出羧甲基纖維素(CMC)、羥乙基纖維素(HEC)、羧乙基纖維素、甲基纖維素、乙基纖維素、氰乙基纖維素、氧乙基纖維素、聚偏二氟乙烯系樹脂等。此外，黏合劑能夠作為水溶液或水分散液使用，亦可以採用市售產品。作為市售產品，例如，可列舉出日新化成(株)製「POVACOAT」(註冊商標)；東亞合成(株) 製「JURYMER」(註冊商標)AT-510、ET-410、FC-60、SEK-301；大成精細化學(株)製UW-223SX、UW-550CS；DIC(株)製WE-301、EC-906EF、CG-8490；Arkema(株)製「KYRNAR」(註冊商標)WATERBORNE；以及東日本塗料(株)製VINYCOAT PVDF AQ360等。重視耐熱性時，較佳為聚乙烯醇、丙烯酸系樹脂，重視電極黏合性、與非水電解液之親和性時，較佳為聚偏二氟乙烯系樹脂。 The binder has a function of imparting or enhancing the function and binding inorganic particles to each other, and a function of bonding a laminated polyolefin microporous film to a porous layer. Examples of the binder include polyvinyl alcohol, a cellulose ether resin, and an acrylic resin. Examples of the cellulose ether resin include carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), carboxyethyl cellulose, methyl cellulose, ethyl cellulose, cyanoethyl cellulose, Oxyethyl cellulose, polyvinylidene fluoride resin and the like. In addition, the adhesive can be used as an aqueous solution or an aqueous dispersion, and a commercially available product can also be used. Examples of commercially available products include "POVACOAT" (registered trademark) manufactured by Nisshin Chemical Co., Ltd .; "JURYMER" (registered trademark) manufactured by Toa Kosei Co., Ltd. AT-510, ET-410, FC-60, SEK-301; UW-223SX, UW-550CS manufactured by Dacheng Fine Chemical Co., Ltd .; WE-301, EC-906EF, CG-8490 manufactured by DIC Corporation; "KYRNAR" (registered trademark) WATERBORNE manufactured by Arkema Corporation; And VINYCOAT PVDF AQ360 manufactured by East Japan Paint Co., Ltd. When heat resistance is important, polyvinyl alcohol and an acrylic resin are preferable, and when electrode adhesion and affinity with a nonaqueous electrolytic solution are important, a polyvinylidene fluoride resin is preferable.

無機顆粒之平均粒徑較佳為積層聚烯烴微多孔膜之平均細孔徑之1.5倍以上50倍以下，更佳為2倍以上20倍以下。如果顆粒之平均粒徑係上述較佳範圍，則於耐熱性樹脂與顆粒混合於一起之狀態下可防止阻塞積層聚烯烴微多孔膜之細孔，結果能夠維持氣阻度。此外，於電池組裝製程中，可防止顆粒脫落而導致電池發生重大缺陷。 The average particle diameter of the inorganic particles is preferably 1.5 times to 50 times, and more preferably 2 times to 20 times the average pore diameter of the laminated polyolefin microporous film. If the average particle diameter of the particles is in the above-mentioned preferable range, the pores of the laminated polyolefin microporous film can be prevented from being blocked in a state where the heat-resistant resin and the particles are mixed together, and as a result, the degree of air resistance can be maintained. In addition, during the battery assembly process, particles can be prevented from causing serious defects in the battery.

為防止起因於電極材料之枝晶導致短路，多孔層含有無機顆粒很重要。作為無機顆粒，可列舉出碳酸鈣、磷酸鈣、非晶性二氧化矽、結晶性玻璃填料、高嶺土、滑石、二氧化鈦、氧化鋁、二氧化矽氧化鋁復合氧化物顆粒、硫酸鋇、氟化鈣、氟化鋰、沸石、硫化鉬、雲母、勃姆石等。此外，根據需要亦可以添加耐熱***聯高分子顆粒。作為耐熱***聯高分子顆粒，可列舉出交聯聚苯乙烯顆粒、交聯丙烯酸系樹脂顆粒、交聯甲基丙烯酸甲酯系顆粒等。無機顆粒之形狀可 列舉出正圓球形狀、近圓球形狀、板狀、針狀、多面體形狀，但並無特別限定。 In order to prevent a short circuit due to dendrites of the electrode material, it is important that the porous layer contains inorganic particles. Examples of the inorganic particles include calcium carbonate, calcium phosphate, amorphous silica, crystalline glass filler, kaolin, talc, titanium dioxide, alumina, silica alumina composite oxide particles, barium sulfate, and calcium fluoride. , Lithium fluoride, zeolite, molybdenum sulfide, mica, boehmite, etc. In addition, heat-resistant crosslinked polymer particles may be added as necessary. Examples of the heat-resistant crosslinked polymer particles include crosslinked polystyrene particles, crosslinked acrylic resin particles, and crosslinked methyl methacrylate particles. Examples of the shape of the inorganic particles include a perfect spherical shape, a nearly spherical shape, a plate shape, a needle shape, and a polyhedron shape, but are not particularly limited.

多孔層中含有之無機顆粒之含量之上限較佳為98vol%，更佳為95vol%。下限較佳為50vol%，更佳為60vol%。如果顆粒之添加量係上述較佳範圍，則捲曲降低功效充分，對多孔層之總體積而言功能性樹脂之比例最佳。 The upper limit of the content of the inorganic particles contained in the porous layer is preferably 98 vol%, and more preferably 95 vol%. The lower limit is preferably 50 vol%, and more preferably 60 vol%. If the added amount of the particles is in the above-mentioned preferred range, the curl reduction effect is sufficient, and the ratio of the functional resin to the total volume of the porous layer is optimal.

多孔層之平均厚度T(ave)之下限較佳為1μm，更佳為1.5μm，進一步較佳為2.0μm，上限較佳為5μm，更佳為4μm，進一步較佳為3μm。如果多孔層之膜厚係上述較佳範圍，則能夠抑制多孔層之厚度變動幅度(R)。將多孔層積層而得到之電池用隔膜於熔點以上進行熔融及收縮時能夠確保破膜強度與絕緣性。此外，能夠抑制捲繞量，適用於電池高容量化。 The lower limit of the average thickness T (ave) of the porous layer is preferably 1 μm, more preferably 1.5 μm, even more preferably 2.0 μm, and the upper limit is preferably 5 μm, more preferably 4 μm, and even more preferably 3 μm. If the film thickness of the porous layer is in the above-mentioned preferable range, the thickness fluctuation range (R) of the porous layer can be suppressed. The battery separator obtained by laminating porous layers can ensure film breaking strength and insulation when melting and shrinking above the melting point. In addition, the amount of winding can be suppressed, which is suitable for increasing the capacity of a battery.

多孔層之空孔率較佳為30%至90%，更佳為40%至70%。所需要之空孔率可通過適當調節無機顆粒之濃度、黏合劑濃度等而得到。 The porosity of the porous layer is preferably 30% to 90%, and more preferably 40% to 70%. The required porosity can be obtained by appropriately adjusting the concentration of the inorganic particles, the concentration of the binder, and the like.

3.將多孔層積層至積層聚烯烴微多孔膜之積層方法 3. Laminating method of laminating porous layers to laminated polyolefin microporous films

接著，對將多孔層積層至本發明之積層聚烯烴微多孔膜之積層方法進行說明。 Next, a method for laminating a porous layer to a laminated polyolefin microporous film of the present invention will be described.

本發明通過將多孔層積層至長度方向之F25值之變動幅度係1MPa以下之積層聚烯烴微多孔膜，能夠得到電池用隔膜。通過使用本發明之積層聚烯烴微多孔膜，從而與塗佈輥之切線(以下簡稱為塗佈切線)之接觸壓力相對於積層聚烯烴微多孔膜之長度方向容易變得均勻，且容易將塗佈厚度設置得均勻。 According to the present invention, a laminated polyolefin microporous film having a variation range of F25 value in the longitudinal direction from a porous layer to 1 MPa or less can be used to obtain a battery separator. By using the laminated polyolefin microporous film of the present invention, the contact pressure with the tangent line of the coating roller (hereinafter simply referred to as the coating tangent line) is easy to become uniform with respect to the length direction of the laminated polyolefin microporous film, and it is easy to apply the coating. The cloth thickness is set evenly.

將多孔層積層至積層聚烯烴微多孔膜之方法例如有以下方法：使用後述眾所周知之輥塗佈法，使用後述方法以指定膜厚將含有樹脂、無機顆粒及分散溶劑之塗佈液塗佈至積層聚烯烴微多孔膜，並於乾燥溫度40℃至80℃、乾燥時間5秒至60秒之條件下進行乾燥。溶劑例如可列舉出水、醇類、及其混合液等。 A method for laminating a porous layer to a laminated polyolefin microporous film is, for example, the following method: A coating solution containing a resin, inorganic particles, and a dispersion solvent is applied to a specified film thickness using a well-known roll coating method described later and a method described later is used to The polyolefin microporous membrane is laminated and dried under the conditions of a drying temperature of 40 ° C to 80 ° C and a drying time of 5 seconds to 60 seconds. Examples of the solvent include water, alcohols, and mixed liquids thereof.

作為輥塗佈法，例如可列舉出逆轉輥塗佈法、凹版塗佈法等，能夠單獨進行這些方法或者將這些方法組合進行。其中，從塗佈厚度之均勻化之觀點出發，較佳為凹版塗佈法。 Examples of the roll coating method include a reverse roll coating method and a gravure coating method. These methods can be performed alone or in combination. Among them, a gravure coating method is preferred from the viewpoint of uniform coating thickness.

本發明中輥塗佈法之輥與積層聚烯烴微多孔膜之塗佈切線之粗細較佳為3mm以上10mm以下。如果塗佈切線之粗細超過10mm，則積層聚烯烴微多孔膜與塗佈輥之接觸壓力較大，容易對塗佈面造成劃痕。 The thickness of the coating tangent of the roll of the roll coating method and the laminated polyolefin microporous film in the present invention is preferably 3 mm or more and 10 mm or less. If the thickness of the coating tangent exceeds 10 mm, the contact pressure between the laminated polyolefin microporous film and the coating roller is large, and it is easy to cause scratches on the coating surface.

本說明書所提及之塗佈切線係塗佈輥與積層聚烯烴微多孔膜相接之線，塗佈切線之粗細係指塗佈切線之長度方向之寬度(參照圖5)。塗佈切線之粗細能夠通過從積層聚烯烴微多孔膜之背面觀察塗佈輥與積層聚烯烴微多孔膜之塗佈切線而進行測定。能夠通過對塗佈輥相對於積層聚烯烴微多孔膜之位置進行前後調節，或者對配置於塗佈面之背後之支撐輥相對於水平方向之左右位置平衡進行調節，來調節塗佈切線之粗細。支撐輥相對於塗佈輥配置於上游側、下游側之兩方更有功效。 The coating tangent line mentioned in this specification refers to the line where the coating roller is connected to the laminated polyolefin microporous film, and the thickness of the coating tangent line refers to the width in the longitudinal direction of the coating tangent line (see FIG. 5). The thickness of the coating tangent can be measured by observing the coating tangent of the coating roller and the laminated polyolefin microporous film from the back surface of the laminated polyolefin microporous film. The thickness of the coating tangent can be adjusted by adjusting the position of the coating roller relative to the laminated polyolefin microporous film, or adjusting the balance of the horizontal position of the support roller located behind the coating surface with respect to the horizontal direction. . The support roller is more effective than the coating roller disposed on both the upstream side and the downstream side.

輥塗佈法之塗佈輥之擺動精度較佳為10μm/Φ 100mm以下，更佳為8μm/Φ 100mm以下，進一步較佳為5μm/Φ 100mm以下。如果塗佈輥之擺動精度係上述範圍內，則相對於長度方向亦容易得到均勻之塗佈厚度。塗佈輥之擺動精度越高越昂貴，但這一點為達成本發明之課題很重要。 The swing accuracy of the coating roller of the roll coating method is preferably 10 μm / Φ 100 mm or less, more preferably 8 μm / Φ 100 mm or less, and still more preferably 5 μm / Φ 100 mm or less. If the swing accuracy of the coating roller is within the above range, it is easy to obtain a uniform coating thickness with respect to the longitudinal direction. The higher the swing accuracy of the coating roller is, the more expensive it is, but it is important to achieve the subject of the cost invention.

本說明書中隔膜之長度方向之多孔層之厚度均勻係指，相對於隔膜長度1000m以上，厚度之變動幅度(R)係1.0μm以下。厚度之變動幅度(R)較佳為0.8μm以下，更佳為0.5μm以下。 In this specification, the uniform thickness of the porous layer in the longitudinal direction of the separator means that the thickness variation range (R) is 1.0 μm or less with respect to the separator length of 1000 m or more. The thickness variation range (R) is preferably 0.8 μm or less, and more preferably 0.5 μm or less.

塗佈液之固體濃度只要能夠均勻塗佈，則並無特別限制，較佳為20重量百分比以上80重量百分比以下，更佳為 50重量百分比以上70重量百分比以下。如果塗佈液之固體濃度係上述較佳範圍，則容易得到均勻之塗佈厚度，能夠防止多孔層變脆。 The solid concentration of the coating liquid is not particularly limited as long as it can be uniformly coated, but it is preferably from 20% by weight to 80% by weight, and more preferably from 50% by weight to 70% by weight. If the solid concentration of the coating liquid is in the above-mentioned preferred range, a uniform coating thickness can be easily obtained, and the porous layer can be prevented from becoming brittle.

4.電池用隔膜 4. Battery separator

從機械強度、電池容量之觀點出發，將多孔層積層至積層聚烯烴微多孔膜而得到之電池用隔膜之膜厚較佳為6μm至30μm。電池用隔膜之寬度並無特別限制，下限較佳為30mm，更佳為60mm，進一步較佳為100mm，上限較佳為2000mm，更佳為1000mm，進一步較佳為800mm。如果電池用隔膜之厚度係上述範圍，則適用於高容量電池製作，不易因自重而產生撓曲。 From the viewpoints of mechanical strength and battery capacity, the film thickness of the battery separator obtained by laminating porous layers to laminated polyolefin microporous films is preferably 6 μm to 30 μm. The width of the battery separator is not particularly limited. The lower limit is preferably 30 mm, more preferably 60 mm, even more preferably 100 mm, and the upper limit is preferably 2000 mm, more preferably 1000 mm, and even more preferably 800 mm. If the thickness of the battery separator is in the above range, it is suitable for the production of high-capacity batteries, and it is not easy to be deformed due to its own weight.

電池用隔膜之長度之下限較佳為1000m，更佳為2000m，進一步較佳為3000m。上限並無特殊規定，較佳為10000m，更佳為8000m，進一步較佳為7000m。如果電池用隔膜之長度係上述範圍，則可提高生產效率，並且作為捲繞體時不易因自重而產生撓曲。 The lower limit of the length of the battery separator is preferably 1000 m, more preferably 2000 m, and still more preferably 3000 m. The upper limit is not particularly limited, but it is preferably 10,000 m, more preferably 8000 m, and even more preferably 7000 m. When the length of the battery separator is within the above range, production efficiency can be improved, and when it is used as a wound body, it is unlikely to be deformed due to its own weight.

電池用隔膜較佳為以乾燥狀態進行保存，難以以極乾燥狀態進行保存時，較佳為於即將使用前進行100℃以下之減壓乾燥處理。 The battery separator is preferably stored in a dry state. When it is difficult to store the battery separator in an extremely dry state, it is preferable to perform a reduced-pressure drying treatment of 100 ° C or lower immediately before use.

本發明之電池用隔膜能夠作為鎳氫電池、鎳鎘電池、鎳鋅電池、銀鋅電池、鋰二次電池、鋰聚合物二次電池等二次電池、以及塑料薄膜電容器、陶瓷電容器、電雙層電容器等隔膜使用，特別較佳為作為鋰離子二次電池之隔膜使用。下面以鋰離子二次電池為示例進行說明。鋰離子二次電池含有正極及負極經由隔膜積層之電極體與電解液(電解質)。電極體之結構並無特別限定，可以係眾所周知之結構。例如，能夠採用圓盤狀之正極及負極以相對方式配置之電極結構(硬幣型)、平板狀之正極及負極交互積層之電極結構(積層型)、帶狀之正極及負極重疊捲繞之電極結構(捲繞型)等結構。 The battery separator of the present invention can be used as a secondary battery such as a nickel-metal hydride battery, a nickel-cadmium battery, a nickel-zinc battery, a silver-zinc battery, a lithium secondary battery, a lithium polymer secondary battery, a plastic film capacitor, a ceramic capacitor, and an electric double battery. Use of a separator such as a layer capacitor is particularly preferred as a separator for a lithium ion secondary battery. The following description uses a lithium ion secondary battery as an example. The lithium ion secondary battery includes an electrode body in which a positive electrode and a negative electrode are laminated via a separator, and an electrolytic solution (electrolyte). The structure of the electrode body is not particularly limited, and may be a well-known structure. For example, a disc-shaped positive electrode and a negative electrode electrode structure (coin type), a flat plate-shaped positive electrode and negative electrode alternately laminated electrode structure (laminated type), and a strip-shaped positive electrode and negative electrode can be stacked and wound. Structure (winding type) and other structures.

[實施例]     [Example]    

下面示出實施例具體地進行說明，但本發明並不受這些實施例之任何限制。另外，實施例中之測定值係使用以下方法測定之值。 Examples will be specifically described below, but the present invention is not limited in any way by these examples. In addition, the measured value in an Example is a value measured using the following method.

1.F25值之變動幅度之測定 1.Measurement of fluctuation range of F25 value

相對於實施例及比較例中得到之積層聚烯烴微多孔膜之寬度方向以等間隔切下5個TD10mm×MD50mm之試驗片。兩端部之試驗片從距離微多孔膜之寬度方向之端部30mm至40mm之部位切下。依據JIS K7113，使用桌上型精密萬能試驗機(Autograph AGS-J((株)島津製作所製))，求出試驗片之長度方向之SS曲線(垂直應力(stress)與垂直形 變(strein)之關係)。讀取垂直形變伸長25%時之垂直應力值，將該值除以試驗前之各試驗片之剖面積求出之值設為F25值，求出5個寬度方向之平均值。相對於長度方向以250m間隔對5個部位，求出F25值之寬度方向之各平均值，根據其最大值與最小值之差求出F25值之變動幅度。另外，亦可以將從電池用隔膜上將多孔層剝離除去之積層聚烯烴微多孔膜作為試驗片使用。 With respect to the width direction of the laminated polyolefin microporous film obtained in the examples and comparative examples, five test pieces of TD10 mm × MD50 mm were cut at equal intervals. The test pieces at both end portions were cut from a position 30 mm to 40 mm from the end portion in the width direction of the microporous membrane. According to JIS K7113, a desktop precision universal testing machine (Autograph AGS-J (manufactured by Shimadzu Corporation)) was used to determine the SS curve (vertical stress and vertical strein) in the longitudinal direction of the test piece. relationship). The vertical stress value at 25% elongation of the vertical deformation was read, and the value obtained by dividing this value by the cross-sectional area of each test piece before the test was set to the F25 value, and the average value in 5 width directions was obtained. For each of the five positions at 250 m intervals with respect to the length direction, the average values in the width direction of the F25 value were obtained, and the fluctuation range of the F25 value was obtained based on the difference between the maximum value and the minimum value. In addition, a laminated polyolefin microporous film in which a porous layer is peeled off from a battery separator may be used as a test piece.

．測定條件 ． Measurement conditions

稱重感應器容量：1kN Load sensor capacity: 1kN

夾鉗間距離：20mm Distance between clamps: 20mm

試驗速度：20mm/min Test speed: 20mm / min

測定環境：氣溫20℃、相對濕度60% Measurement environment: air temperature 20 ℃, relative humidity 60%

2.多孔層之膜厚之長度方向之變動幅度(R) 2. Variation of the thickness of the porous layer in the length direction (R)

相對於實施例及比較例中得到之積層聚烯烴微多孔膜之寬度方向以等間隔切下5個TD10mm×MD50mm之試驗片。兩端部之試驗片從距離微多孔膜之寬度方向之端部30mm至40mm之部位切下。通過對各試驗片之剖面進行SEM觀察來求出多孔層之厚度。剖面試驗片使用低溫CP法製作，為防止電子束導致充電，蒸鍍少許金屬微顆粒進行SEM觀察。將存在無機顆粒之區域作為多孔層測定膜厚，求出5個寬度方向之平均值。相對於長度方向以250m間隔對5個部位，求出寬度方向之各平均值，根據其最大值與最 小值之差求出相對於長度方向之多孔層之厚度之變動幅度(R)。將上述共計25個試驗片之厚度之平均值設為多孔層之平均厚度T(ave)。 With respect to the width direction of the laminated polyolefin microporous film obtained in the examples and comparative examples, five test pieces of TD10 mm × MD50 mm were cut at equal intervals. The test pieces at both end portions were cut from a position 30 mm to 40 mm from the end portion in the width direction of the microporous membrane. The thickness of the porous layer was determined by SEM observation of the cross section of each test piece. The cross-section test piece was produced by the low-temperature CP method. To prevent the electron beam from causing charge, a small amount of metal fine particles were vapor-deposited for SEM observation. The film thickness was measured using the area where the inorganic particles were present as a porous layer, and the average value in 5 width directions was determined. The average value in the width direction was calculated for each of the five positions at intervals of 250 m with respect to the length direction, and the variation range (R) with respect to the thickness of the porous layer in the length direction was calculated based on the difference between the maximum value and the minimum value. The average value of the thicknesses of the above-mentioned 25 test pieces was taken as the average thickness T (ave) of the porous layer.

．測定裝置 ． Measuring device

電場放射型掃描電子顯微鏡(FE-SEM)S-4800((株)日立高新技術公司製) Electric field emission scanning electron microscope (FE-SEM) S-4800 (manufactured by Hitachi High-tech Co., Ltd.)

剖面試料調製裝置(CP：Cross-section Polisher)SM-9010(日本電子(株)製) Section sample preparation device (CP: Cross-section Polisher) SM-9010 (manufactured by Japan Electronics Co., Ltd.)

．測定條件 ． Measurement conditions

加速電壓：1.0kV Acceleration voltage: 1.0kV

3.縱向拉伸輥之表面溫度之變動幅度 3. Variation of surface temperature of longitudinal stretching roller

用紅外放射溫度計每隔5分鐘對各輥之表面進行測定共計5次，根據最大值與最小值之差求出縱向拉伸輥之表面溫度之變動幅度。 The surface of each roll was measured 5 times every 5 minutes with an infrared radiation thermometer, and the fluctuation range of the surface temperature of the longitudinal stretching roll was obtained based on the difference between the maximum value and the minimum value.

4.塗佈切線之粗細測定 4. Determination of thickness of coating tangent

塗佈切線係指塗佈時塗佈輥與積層聚烯烴微多孔膜相接之寬度方向之線。塗佈切線之粗細係塗佈切線之長度方向之寬度，係指使用量規穿過積層聚烯烴微多孔膜之背面讀取之值。 The coating tangent line refers to a line in the width direction where the coating roller is in contact with the laminated polyolefin microporous film during coating. The thickness of the coating tangent line is the width in the longitudinal direction of the coating tangent line, and refers to the value read through the back surface of the laminated polyolefin microporous membrane using a gauge.

5.捲繞狀態 5. Winding state

肉眼觀察實施例及比較例中得到之電池用隔膜之捲繞體，數出發生撓曲、捲偏之部位之數量。 The wound body of the battery separator obtained in the examples and comparative examples was visually observed, and the number of the portions where deflection and deflection occurred was counted.

．判定基準 ． Judgment criteria

○(良好)：無 ○ (Good): None

△(良好)：1至3個 △ (Good): 1 to 3

×(不良)：4個以上 × (bad): 4 or more

6.劃痕之評估 6. Evaluation of scratches

從實施例及比較例中得到之電池用隔膜之捲繞體上將最外周部分去除後，抽出內周部分1m²，作為評估用試料。劃痕檢測中，對塗佈面照射鹵光燈(brom light)(照片拍攝、錄像攝影時使用之照明器具)，肉眼檢測劃痕，數出數量。 After removing the outermost peripheral part from the wound body of the battery separator obtained in the examples and comparative examples, the inner peripheral part was taken out as 1 m ² as a sample for evaluation. In the scratch detection, the coated surface is irradiated with a brom light (lighting equipment used for photo shooting and video shooting), and the scratch is detected by the naked eye, and the number is counted.

．判定基準 ． Judgment criteria

○(良好)：1個部位以下 ○ (Good): 1 or less

△(良好)：2至5個部位 △ (Good): 2 to 5 locations

×(不良)：6個部位以上 × (defective): 6 or more

7.膜厚 7. Film thickness

通過使用接觸式膜厚計((株)三豐製Litematic series318)求出20個測定值之平均值來求出。使用超硬球面測定頭φ 8.5mm，以加重0.01N之條件進行測定。 It was calculated | required by obtaining the average value of 20 measured values using the contact-type film thickness meter (Litematic series 318 by Mitutoyo). The measurement was performed with a super hard spherical measuring head φ 8.5 mm and a weight of 0.01 N.

8.平均孔徑 8. average pore size

積層聚乙烯微多孔膜之平均孔徑利用以下方法測定。利用雙面膠將試料固定於測定用稱重感應器上，將鉑金或金進行數分鐘真空蒸鍍，以適當倍率對膜之表面進行SEM測定。於SEM測定中得到之影像上選擇任意10個部位，將該10個部位之孔徑之平均值設為試料之平均孔徑。 The average pore diameter of the laminated polyethylene microporous membrane was measured by the following method. The sample was fixed to the load cell for measurement with double-sided tape, and platinum or gold was vacuum-evaporated for several minutes, and the surface of the film was subjected to SEM measurement at an appropriate magnification. Any 10 positions were selected from the images obtained by the SEM measurement, and the average of the pore diameters of the 10 positions was set as the average pore diameter of the sample.

9.氣阻度(sec/100ccAir) 9.Air resistance (sec / 100ccAir)

使用試驗機產業(株)製之葛爾萊透氣度測定儀(Gurley type densometer)B型，將積層聚乙烯微多孔膜或電池用隔膜固定於夾模板與適配器板之間以免產生褶皺，依據JIS P8117進行測定。試料為邊長10cm方形，測定點為試料之中央部與4個角共計5個，使用其平均值作為氣阻度。另外，試料之1邊長度不足10cm時，亦可以使用以5cm間隔測定5個之值。 A Gurley type densometer B type manufactured by Tester Industries Co., Ltd. is used to fix the laminated polyethylene microporous membrane or battery separator between the clamp plate and the adapter plate to prevent wrinkles. According to JIS P8117 was measured. The sample is a square with a side length of 10 cm, and the measurement points are a total of 5 at the center of the sample and 4 corners. The average value is used as the air resistance. In addition, when the length of one side of the sample is less than 10 cm, a value of 5 pieces may be measured at 5 cm intervals.

氣阻度之上升幅度利用下述公式求出。 The increase in air resistance is calculated using the following formula.

氣阻度之上升幅度=(Y)-(X)sec/100ccAir Rise of air resistance = (Y)-(X) sec / 100ccAir

積層聚乙烯微多孔膜之氣阻度(X)sec/100ccAir Air resistance (X) sec / 100ccAir of laminated polyethylene microporous membrane

電池用隔膜之氣阻度(Y)sec/100ccAir Air barrier of battery separator (Y) sec / 100ccAir

10.切斷溫度 10. Cut-off temperature

以5℃/min之升溫速度對積層聚乙烯微多孔膜進行加熱，同時利用王研式氣阻度計(旭精工株式會社製、EGO-1T)測定氣阻度，求出氣阻度達到檢測極限1×10⁵秒/100ccAir 之溫度，作為切斷溫度(℃)。 The laminated polyethylene microporous membrane was heated at a heating rate of 5 ° C / min. At the same time, the air-blocking degree was measured using a Wangken-type air resistance meter (manufactured by Asahi Seiko Co., Ltd., EGO-1T), and the air-blocking degree was detected. The limit temperature is 1 × 10 ⁵ seconds / 100ccAir, which is the cut-off temperature (° C).

11.氣阻度上升率 11. Rising rate of air resistance

根據上述7.之切斷溫度測定中得到之厚度T1(μm)之積層聚乙烯微多孔膜之溫度與氣阻度P之數據，繪製溫度30℃至105℃之溫度與氣阻度P之關係圖，利用最小二乘法算出斜率Pa(sec/100ccAir/℃)。將算出之Pa代入公式Pb=Pa/T1×20，將膜厚20μm標準化，算出30℃至105℃之氣阻度上升率Pb(秒/100ccAir/μm/℃)。 According to the data of the temperature of the laminated polyethylene microporous membrane with a thickness of T1 (μm) and the air resistance degree P obtained in the measurement of the cutting temperature of 7. above, the relationship between the temperature of 30 ° C to 105 ° C and the air resistance degree P In the graph, the slope Pa (sec / 100ccAir / ° C) is calculated by the least square method. Substitute the calculated Pa into the formula Pb = Pa / T1 × 20, normalize the film thickness to 20 μm, and calculate the air resistance increase rate Pb (sec / 100ccAir / μm / ℃) from 30 ° C to 105 ° C.

12.積層聚烯烴微多孔膜之空孔率 12. Porosity of laminated polyolefin microporous membrane

準備邊長10cm方形試料，對該試料體積(cm³)與質量(g)進行測定，根據得到之結果使用一下公式計算出空孔率(%)。 A square sample with a side length of 10 cm was prepared, and the volume (cm ³ ) and mass (g) of the sample were measured. Based on the obtained results, the porosity (%) was calculated using the following formula.

空孔率=(1-質量/(樹脂密度×試料體積))×100 Porosity = (1-mass / (resin density × sample volume)) × 100

13.重量平均分子量(Mw)及分子量分佈(Mw/Mn) 13. Weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn)

Mw及Mw/Mn按以下條件利用凝膠滲透色譜(GPC)法求出。 Mw and Mw / Mn were determined by a gel permeation chromatography (GPC) method under the following conditions.

．測定裝置：Waters Corporation製GPC-150C ． Measuring device: GPC-150C manufactured by Waters Corporation

．色譜柱：昭和電工(株)製「Shodex」(註冊商標)UT806M ． Column: "Shodex" (registered trademark) UT806M, manufactured by Showa Denko Corporation

．色譜柱溫度：135℃ ． Column temperature: 135 ° C

．溶劑(移動相)：鄰二氯苯 ． Solvent (mobile phase): o-dichlorobenzene

．溶劑流速：1.0ml/分鐘 ． Solvent flow rate: 1.0ml / min

．試料濃度：0.1質量百分比(溶解條件：135℃/1h) ． Sample concentration: 0.1% by mass (dissolution conditions: 135 ° C / 1h)

．注入量：500μl ． Injection volume: 500 μl

．檢測器：Waters Corporation製示差折射計 ． Detector: Differential refractometer manufactured by Waters Corporation

．檢量線：根據使用單分散聚苯乙烯標準試料得到之檢量線，使用指定換算常數製作。 ． Calibration curve: According to the calibration curve obtained by using monodisperse polystyrene standard sample, the specified conversion constant is used.

14.熔體流動速率(MFR) 14. Melt Flow Rate (MFR)

依據JIS-K7210，以溫度190℃、荷載2.16g進行測定。 According to JIS-K7210, the measurement was performed at a temperature of 190 ° C and a load of 2.16 g.

15.熔點 15. Melting point

使用精工納米科技株式會社製之示差掃描熱量計(DSC)DSC6220，將於氮氣環境下以升溫速度20℃/分鐘將5mg樹脂試料升溫時觀察之熔解峰值之頂點溫度設為熔點。 Using a differential scanning calorimeter (DSC) DSC6220 manufactured by Seiko Nano Technology Co., Ltd., the apex temperature of the melting peak observed when a 5 mg resin sample was heated at a temperature increase rate of 20 ° C / minute under a nitrogen atmosphere was set as the melting point.

(塗佈液之製作) (Production of coating liquid)

參考例1 Reference example 1

將作為黏合劑之聚乙烯醇(平均聚合度1700、皂化度99%以上)、作為無機顆粒之平均粒徑0.5μm之氧化鋁顆粒、離子交換水分別以6：54：40之重量比率配混，並充分攪拌，使其均勻分散。接著，用過濾極限5μm之過濾器進行過濾，得到塗佈液(a)。 Polyvinyl alcohol (average degree of polymerization 1700, saponification degree of 99% or more) as a binder, alumina particles having an average particle size of 0.5 μm as inorganic particles, and ion-exchanged water were compounded at a weight ratio of 6:54:40, respectively. And stir well to make it evenly dispersed. Then, it filtered with the filter with a filtration limit of 5 micrometers, and obtained the coating liquid (a).

參考例2 Reference example 2

將作為黏合劑之聚乙烯醇及丙烯酸及甲基丙烯酸甲酯之共聚物(「POVACOAT」(註冊商標)、日新化成(株)製)、作為無機顆粒之平均粒徑0.5μm之氧化鋁顆粒、溶劑(離子交換水：乙醇=70：30)分別以5：45：50之重量比率配混，並充分攪拌，使其均勻分散。接著，用過濾極限5μm之過濾器進行過濾，得到塗佈液(b)。 Polyvinyl alcohol as a binder, a copolymer of acrylic acid and methyl methacrylate ("POVACOAT" (registered trademark), manufactured by Nisshin Chemical Co., Ltd.), and alumina particles having an average particle diameter of 0.5 m as inorganic particles 3. Solvent (ion-exchanged water: ethanol = 70: 30) is compounded at a weight ratio of 5:45:50, and fully stirred to make it uniformly dispersed. Then, it filtered with the filter with a filtration limit of 5 micrometers, and obtained the coating liquid (b).

參考例3 Reference example 3

將作為黏合劑之聚偏二氟乙烯系樹脂之水系乳狀液(VINYCOAT PVDF AQ360、東日本塗料(株)製)、作為無機顆粒之平均粒徑0.5μm之氧化鋁顆粒、離子交換水分別以30：30：40之重量比率配混，並充分攪拌，使其均勻分散。接著，用過濾極限5μm之過濾器進行過濾，得到塗佈液(c)。 An aqueous emulsion of a polyvinylidene fluoride resin (VINYCOAT PVDF AQ360, manufactured by Tohoku Paint Co., Ltd.) as an adhesive, alumina particles having an average particle diameter of 0.5 μm as inorganic particles, and ion-exchanged water were each divided into The weight ratio of 30:40 is compounded and stirred well to make it uniformly dispersed. Then, it filtered with the filter with a filtration limit of 5 micrometers, and obtained the coating liquid (c).

(積層聚烯烴微多孔膜之製造) (Manufacture of laminated polyolefin microporous membrane)

實施例1 Example 1

由重量平均分子量200萬之超高分子量聚乙烯(UHMWPE)18質量百分比及重量平均分子量35萬之高密度聚乙烯(HDPE)82質量百分比構成組合物100質量百分比，對其添加抗氧化劑(四[亞甲基-(3',5'-二叔丁基-4'-羥苯基)丙酸酯]甲烷)0.375質量百分比，得到第一聚乙烯組合物(熔點135℃)。將該第一聚乙烯組合物25質量百分比投入雙軸擠出機。從該雙軸擠出機之側送料器供給液體石蠟75質量百 分比，進行熔融混煉，於擠出機中調製出第一聚乙烯樹脂溶液。 The composition is composed of 18% by mass of ultra-high molecular weight polyethylene (UHMWPE) with a weight average molecular weight of 2 million and 82% by mass of high density polyethylene (HDPE) with a weight average molecular weight of 350,000, and an antioxidant (four [ Methylene- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate] methane) 0.375 mass% to obtain a first polyethylene composition (melting point: 135 ° C). 25 mass% of this first polyethylene composition was charged into a biaxial extruder. 75 mass% of liquid paraffin was supplied from the side feeder of the twin-screw extruder, melt-kneaded, and a first polyethylene resin solution was prepared in the extruder.

另一方面，由重量平均分子量200萬之超高分子量聚乙烯(UHMWPE)17.5質量百分比及重量平均分子量30萬之高密度聚乙烯(HDPE)57.5質量百分比、MFR係135g/10min且熔點124℃之直鏈狀低密度聚乙烯(乙烯-1-己烯共聚物)25質量百分比構成組合物100質量百分比，對其添加抗氧化劑(四[亞甲基-(3',5'-二叔丁基-4'-羥苯基)丙酸酯]甲烷)0.375質量百分比，得到第二聚乙烯組合物(熔點128℃)。將該第二聚乙烯組合物25質量百分比投入雙軸擠出機。從該雙軸擠出機之側送料器供給液體石蠟75質量百分比，進行熔融混煉，於擠出機中調製出第二聚乙烯樹脂溶液。 On the other hand, the ultra-high molecular weight polyethylene (UHMWPE) with a weight average molecular weight of 2 million is 17.5 percent by mass and the high density polyethylene (HDPE) with a weight average molecular weight of 300,000 is 57.5 percent by mass, the MFR is 135 g / 10 min, and the melting point is 124 ° C. 25% by mass of the linear low-density polyethylene (ethylene-1-hexene copolymer) constitutes 100% by mass of the composition, and an antioxidant (tetra [methylene- (3 ', 5'-di-tert-butyl) is added thereto -4'-hydroxyphenyl) propionate] methane) 0.375 mass% to obtain a second polyethylene composition (melting point: 128 ° C). 25 mass% of this second polyethylene composition was put into a biaxial extruder. 75% by mass of liquid paraffin was supplied from a side feeder of the biaxial extruder, melt-kneaded, and a second polyethylene resin solution was prepared in the extruder.

將得到之第一聚乙烯樹脂溶液及第二聚乙烯樹脂溶液以190℃從積層模頭共擠出，使層構成為第一(聚乙烯樹脂溶液)/第二(聚乙烯樹脂溶液)/第一(聚乙烯樹脂溶液)，使溶液比率為1/2/1，一邊用內部冷卻水溫度保持於25℃之直徑800mm冷卻輥牽引，一邊形成未拉伸膠狀片材。 The obtained first polyethylene resin solution and the second polyethylene resin solution were co-extruded from the lamination die at 190 ° C., so that the layer structure was first (polyethylene resin solution) / second (polyethylene resin solution) / First (polyethylene resin solution), the solution ratio is 1/2/1, and the unstretched gel-like sheet is formed while being pulled by a 800 mm diameter cooling roller maintained at an internal cooling water temperature of 25 ° C.

使所得之未拉伸膠狀片材通過4根預熱輥組，使片材表面之溫度變為110℃，將其引導至圖1所示之縱向拉伸裝置A。縱向拉伸輥使用寬度1000mm、直徑300mm、且實施硬鉻電鍍之金屬輥(表面粗糙度0.5S)。另外，各縱向拉伸輥之表面溫度係110℃。刮刀使用聚酯製刮刀。此外，軋輥使用丁腈橡膠被覆輥((株)加貫Roller製作所製)。使用縱向拉伸 裝置A作為縱向拉伸裝置，使拉伸輥之圓周速度沿向下游前進之方向分階段增大，將第一拉伸輥與第二拉伸輥之圓周速度比設定為1.3，將第二拉伸輥與第三拉伸輥之圓周速度比設定為1.5，將第三拉伸輥與第四拉伸輥之圓周速度比設定為1.8，將第四拉伸輥與第五拉伸輥之圓周速度比設定為2.1。此外，相鄰拉伸輥之間隔將拉伸中之膠狀片材從離開拉伸輥到與下個拉伸輥相接之距離設為200mm，各軋輥之壓力設為0.3MPa。進而，將各拉伸輥之表面溫度變動幅度控制為±2℃。接著，使其通過4根冷卻輥，將片材溫度冷卻至50℃，形成縱向拉伸膠狀片材。 The obtained unstretched gelatinous sheet was passed through four sets of preheating rollers, the temperature of the surface of the sheet was changed to 110 ° C., and it was guided to the longitudinal stretching device A shown in FIG. 1. As the longitudinal stretching roll, a metal roll (surface roughness: 0.5S) having a width of 1000 mm and a diameter of 300 mm and hard chromium plating was used. The surface temperature of each longitudinal stretching roll was 110 ° C. As the doctor blade, a polyester doctor blade was used. As the roll, a nitrile rubber-coated roll (manufactured by Katsuki Roller Co., Ltd.) was used. Use the longitudinal stretching device A as the longitudinal stretching device to increase the circumferential speed of the stretching roller in stages in the direction of downstream advancement, and set the circumferential speed ratio of the first stretching roller to the second stretching roller to 1.3. Set the peripheral speed ratio of the second stretching roller to the third stretching roller to 1.5, set the peripheral speed ratio of the third stretching roller to the fourth stretching roller to 1.8, and set the fourth stretching roller to the fifth stretching roller. The peripheral speed ratio of the draw roller is set to 2.1. In addition, the distance between the adjacent stretching rolls was set to a distance of 200 mm from the distance between the gelatinous sheet stretching from the stretching roll and the next stretching roll, and the pressure of each roll was set to 0.3 MPa. Furthermore, the surface temperature fluctuation range of each stretching roll was controlled to ± 2 ° C. Next, the sheet was passed through four cooling rollers to cool the sheet to 50 ° C. to form a longitudinally stretched gel-like sheet.

用夾鉗夾住得到之縱向拉伸膠狀片材之兩端部，於分割為20個區域之拉幅機內，以溫度115℃沿橫向拉伸6倍，成型雙軸拉伸膠狀片材。此時，相對於片材行進方向，夾鉗之間隔從拉幅機入口到出口設定為5mm。將得到之雙軸拉伸膠狀片材冷卻至30℃，於溫度調節至25℃之二氯甲烷之清洗槽內除去液體石蠟，用調節為60℃之乾燥爐進行乾燥。 The two ends of the longitudinally stretched gelatinous sheet obtained were clamped by clamps, and stretched 6 times in the transverse direction at a temperature of 115 ° C. in a tenter divided into 20 regions to form a biaxially stretched gelatinous sheet. material. At this time, the interval between the clamps was set to 5 mm from the tenter entrance to the exit with respect to the sheet traveling direction. The obtained biaxially stretched gelatinous sheet was cooled to 30 ° C, and the liquid paraffin was removed in a washing tank adjusted to 25 ° C in methylene chloride, and dried in a drying oven adjusted to 60 ° C.

用圖4所示之再拉伸裝置將得到之乾燥後之片材再拉伸，使其縱向倍率為1.2倍，以125℃進行20秒鐘熱處理，得到厚度14μm之積層聚烯烴微多孔膜。進而，將捲繞時之搬運速度設為50m/分鐘，得到寬度4000mm、捲繞長度5050m之積層聚烯烴微多孔膜捲繞體。從得到之捲繞體中抽出積層聚烯烴微多孔膜，縱切加工成寬度950mm，得到作為塗佈用基材使用之積層聚烯烴微多孔膜A。 The obtained dried sheet was re-stretched using a re-stretching device shown in FIG. 4 to achieve a longitudinal magnification of 1.2 times and heat treatment at 125 ° C. for 20 seconds to obtain a laminated polyolefin microporous film having a thickness of 14 μm. Furthermore, the conveyance speed at the time of winding was set to 50 m / min, and the laminated polyolefin microporous membrane roll of 4000 mm in width and 5050 m of winding length was obtained. A laminated polyolefin microporous film was extracted from the obtained wound body, and was slit into a width of 950 mm to obtain a laminated polyolefin microporous film A used as a coating substrate.

實施例2 Example 2

除了將第一聚乙烯組合物之超高分子量聚乙烯(UHMWPE)與高密度聚乙烯(HDPE)之配混比調整為表1所示以外，與實施例1相同，得到積層聚烯烴微多孔膜B。 A laminated polyolefin microporous membrane was obtained in the same manner as in Example 1 except that the compounding ratio of the ultra high molecular weight polyethylene (UHMWPE) and the high density polyethylene (HDPE) of the first polyethylene composition was adjusted to that shown in Table 1. B.

實施例3 Example 3

除了使用圖2所示縱向拉伸裝置B代替縱向拉伸裝置A作為縱向拉伸裝置以外，與實施例2相同，得到積層聚烯烴微多孔膜C。 A laminated polyolefin microporous membrane C was obtained in the same manner as in Example 2 except that the longitudinal stretching apparatus B shown in FIG. 2 was used instead of the longitudinal stretching apparatus A as the longitudinal stretching apparatus.

實施例4 Example 4

除了使用圖3所示縱向拉伸裝置C代替縱向拉伸裝置A作為縱向拉伸裝置以外，與實施例2相同，得到積層聚烯烴微多孔膜D。 A laminated polyolefin microporous membrane D was obtained in the same manner as in Example 2 except that the longitudinal stretching apparatus C shown in FIG. 3 was used instead of the longitudinal stretching apparatus A as the longitudinal stretching apparatus.

實施例5 Example 5

除了使用圖4所示縱向拉伸裝置D代替縱向拉伸裝置A作為縱向拉伸裝置，將縱向拉伸裝置D之第一拉伸輥與第二拉伸輥之圓周速度比設定為1.5，將第二拉伸輥與第三拉伸輥之圓周速度比設定為2.0，將第三拉伸輥與第四拉伸輥之圓周速度比設定為2.5以外，與實施例2相同，得到積層聚烯烴微多孔膜E。 In addition to using the longitudinal stretching device D shown in FIG. 4 instead of the longitudinal stretching device A as the longitudinal stretching device, the peripheral speed ratio of the first stretching roller and the second stretching roller of the longitudinal stretching device D is set to 1.5, and The peripheral speed ratio of the second stretching roller and the third stretching roller was set to 2.0, and the peripheral speed ratio of the third stretching roller and the fourth stretching roller was set to other than 2.5. In the same manner as in Example 2, a laminated polyolefin was obtained. Microporous membrane E.

實施例6 Example 6

除了於縱向拉伸裝置中，將各軋輥之壓力設為0.1MPa以外，與實施例2相同，得到積層聚烯烴微多孔膜F。 A laminated polyolefin microporous film F was obtained in the same manner as in Example 2 except that the pressure of each roll was set to 0.1 MPa in a longitudinal stretching apparatus.

實施例7 Example 7

除了於縱向拉伸裝置中，將各軋輥之壓力設為0.5MPa以外，與實施例2相同，得到積層聚烯烴微多孔膜G。 A laminated polyolefin microporous film G was obtained in the same manner as in Example 2 except that the pressure of each roll was set to 0.5 MPa in a longitudinal stretching device.

實施例8 Example 8

調節各聚乙烯樹脂溶液之擠出量，與實施例2相同，得到厚度7μm之積層聚烯烴微多孔膜H。 The extrusion amount of each polyethylene resin solution was adjusted to be the same as in Example 2 to obtain a laminated polyolefin microporous film H having a thickness of 7 μm.

實施例9 Example 9

除了於縱向拉伸裝置A中，5根縱向拉伸輥均使用表面粗糙度5.0S之陶瓷被覆金屬輥以外，與實施例2相同，得到積層聚烯烴微多孔膜I。 A laminated polyolefin microporous membrane I was obtained in the same manner as in Example 2 except that the five longitudinal stretching rolls each used a ceramic-coated metal roll having a surface roughness of 5.0S.

實施例10 Example 10

除了將縱向拉伸裝置A之第一拉伸輥與第二拉伸輥之圓周速度比設定為1.2，將第二拉伸輥與第三拉伸輥之圓周速度比設定為1.5，將第三拉伸輥與第四拉伸輥之圓周速度比設定為1.8，將第四拉伸輥與第五拉伸輥之圓周速度比設 定為2.3以外，與實施例2相同，得到積層聚烯烴微多孔膜J。 In addition to setting the peripheral speed ratio of the first stretching roller to the second stretching roller of the longitudinal stretching device A to 1.2, the peripheral speed ratio of the second stretching roller to the third stretching roller to 1.5, and the third The peripheral speed ratio between the stretching roller and the fourth stretching roller was set to 1.8, and the peripheral speed ratio between the fourth stretching roller and the fifth stretching roller was set to other than 2.3. In the same manner as in Example 2, a laminated polyolefin microporous was obtained. Membrane J.

實施例11 Example 11

除了將縱向拉伸裝置A之第一拉伸輥與第二拉伸輥之圓周速度比設定為1.3，將第二拉伸輥與第三拉伸輥之圓周速度比設定為1.7，將第三拉伸輥與第四拉伸輥之圓周速度比設定為1.8，將第四拉伸輥與第五拉伸輥之圓周速度比設定為1.9以外，與實施例2相同，得到積層聚烯烴微多孔膜K。 In addition to setting the peripheral speed ratio of the first stretching roller to the second stretching roller of the longitudinal stretching device A to 1.3, the peripheral speed ratio of the second stretching roller to the third stretching roller to 1.7, and the third The peripheral speed ratio between the stretching roller and the fourth stretching roller was set to 1.8, and the peripheral speed ratio between the fourth stretching roller and the fifth stretching roller was set to other than 1.9. In the same manner as in Example 2, a laminated polyolefin microporous material was obtained. Film K.

實施例12至實施例15 Examples 12 to 15

除了將第二聚乙烯組合物中含有之低熔點樹脂變更為表1所示以外，與實施例2相同，得到積層聚烯烴微多孔膜L、積層聚烯烴微多孔膜M、積層聚烯烴微多孔膜N、積層聚烯烴微多孔膜O。 A laminated polyolefin microporous film L, a laminated polyolefin microporous film M, and a laminated polyolefin microporous resin were obtained in the same manner as in Example 2 except that the low-melting resin contained in the second polyethylene composition was changed to that shown in Table 1. Film N, laminated polyolefin microporous film O.

實施例16 Example 16

除了將第二聚乙烯組合物中含有之低熔點樹脂之添加量調節為表1所示以外，與實施例2相同，得到積層聚烯烴微多孔膜P。 A laminated polyolefin microporous film P was obtained in the same manner as in Example 2 except that the addition amount of the low-melting resin contained in the second polyethylene composition was adjusted as shown in Table 1.

實施例17 Example 17

除了使層構成為第一/第二/第一，使溶液比率為1.5/2/1.5以外，與實施例2相同，得到積層聚烯烴微多孔膜Q。 A laminated polyolefin microporous film Q was obtained in the same manner as in Example 2 except that the layer configuration was first / second / first and the solution ratio was 1.5 / 2 / 1.5.

實施例18 Example 18

除了將第一聚乙烯組合物之超高分子量聚乙烯(UHMWPE)與高密度聚乙烯(HDPE)之配混比調整為表1所示以外，與實施例2相同，得到積層聚烯烴微多孔膜R。 A laminated polyolefin microporous membrane was obtained in the same manner as in Example 2 except that the compounding ratio of the ultra high molecular weight polyethylene (UHMWPE) and the high density polyethylene (HDPE) of the first polyethylene composition was adjusted as shown in Table 1. R.

比較例1 Comparative Example 1

用夾鉗夾住實施例2中成型之未拉伸膠狀片材之兩端部，將其引導至溫度調節為116℃且分割為5個區域之拉幅機，利用同時雙軸拉伸法沿縱向拉伸7倍，沿橫向拉伸7倍，成型同時雙軸拉伸膠狀片材。此時，夾鉗之間隔相對於片材行進方向，於拉幅機入口係5mm，於拉幅機出口係95mm。接著，將同時雙軸拉伸膠狀片材冷卻至30℃，於溫度調節至25℃之二氯甲烷之清洗槽內清洗，將除去液體石蠟之片材用調節為60℃之乾燥爐進行乾燥，得到積層聚烯烴微多孔膜。進而，將捲繞時之搬運速度設為50m/分鐘，得到寬度4000mm、捲繞長度5050m之積層聚烯烴微多孔膜捲繞體。從得到之捲繞體中抽出積層聚烯烴微多孔膜，縱切加工成寬度950mm，得到作為塗佈用基材使用之積層聚烯烴微多孔膜a。 Clamp both ends of the unstretched gelatinous sheet formed in Example 2 with a clamp, and guide it to a tenter whose temperature is adjusted to 116 ° C and divided into five regions, and a simultaneous biaxial stretching method is used. It is stretched 7 times in the longitudinal direction and 7 times in the transverse direction, and the gel-like sheet is biaxially stretched while being molded. At this time, the interval of the clamps is 5 mm at the tenter inlet and 95 mm at the tenter outlet relative to the sheet traveling direction. Next, the simultaneous biaxially stretched gelatinous sheet was cooled to 30 ° C, and washed in a dichloromethane washing tank whose temperature was adjusted to 25 ° C, and the liquid paraffin-removed sheet was dried in a drying oven adjusted to 60 ° C. To obtain a laminated polyolefin microporous membrane. Furthermore, the conveyance speed at the time of winding was set to 50 m / min, and the laminated polyolefin microporous membrane roll of 4000 mm in width and 5050 m of winding length was obtained. A laminated polyolefin microporous film was extracted from the obtained wound body, and was slit into a width of 950 mm to obtain a laminated polyolefin microporous film a used as a coating substrate.

比較例2 Comparative Example 2

除了於縱向拉伸裝置A中，5根拉伸輥均不使用軋輥以外，與實施例2相同，得到積層聚烯烴微多孔膜b。 A laminated polyolefin microporous film b was obtained in the same manner as in Example 2 except that none of the five stretching rollers were used in the longitudinal stretching device A.

比較例3 Comparative Example 3

除了使用縱向拉伸裝置B作為縱向拉伸裝置，5根拉伸輥均不使用軋輥以外，與實施例2相同，得到積層聚烯烴微多孔膜c。 A laminated polyolefin microporous film c was obtained in the same manner as in Example 2 except that the longitudinal stretching device B was used as the longitudinal stretching device and no rolls were used for the five stretching rolls.

比較例4 Comparative Example 4

除了於縱向拉伸裝置A中，將各軋輥之壓力設為0.04MPa以外，與實施例2相同，得到積層聚烯烴微多孔膜d。 A laminated polyolefin microporous film d was obtained in the same manner as in Example 2 except that the pressure of each roll was set to 0.04 MPa in the longitudinal stretching device A.

比較例5 Comparative Example 5

除了於縱向拉伸裝置A中，縱向拉伸輥使用表面粗糙度0.1S之實施硬鉻電鍍之金屬輥以外，與實施例2相同，得到積層聚烯烴微多孔膜e。 A laminated polyolefin microporous film e was obtained in the same manner as in Example 2 except that the longitudinal stretching roll A used a metal roll subjected to hard chromium plating with a surface roughness of 0.1S.

比較例6 Comparative Example 6

除了將縱向拉伸裝置A之第一拉伸輥與第二拉伸輥之圓周速度比設定為1.6，將第二拉伸輥與第三拉伸輥之圓周 速度比設定為1.6，將第三拉伸輥與第四拉伸輥之圓周速度比設定為1.7，將第四拉伸輥與第五拉伸輥之圓周速度比設定為1.7以外，與實施例2相同，得到積層聚烯烴微多孔膜f。 In addition to setting the peripheral speed ratio of the first stretching roller to the second stretching roller of the longitudinal stretching device A to 1.6, the peripheral speed ratio of the second stretching roller to the third stretching roller to 1.6, and the third The peripheral speed ratio between the stretching roller and the fourth stretching roller was set to 1.7, and the peripheral speed ratio between the fourth stretching roller and the fifth stretching roller was set to other than 1.7. In the same manner as in Example 2, a laminated polyolefin microporous was obtained Film f.

比較例7 Comparative Example 7

除了將縱向拉伸裝置A之第一拉伸輥與第二拉伸輥之圓周速度比設定為1.1，將第二拉伸輥與第三拉伸輥之圓周速度比設定為1.3，將第三拉伸輥與第四拉伸輥之圓周速度比設定為1.5，將第四拉伸輥與第五拉伸輥之圓周速度比設定為3.5以外，與實施例2相同，得到積層聚烯烴微多孔膜g。 In addition to setting the peripheral speed ratio of the first stretching roller to the second stretching roller of the longitudinal stretching device A to 1.1, the peripheral speed ratio of the second stretching roller to the third stretching roller to 1.3, and the third The peripheral speed ratio between the stretching roller and the fourth stretching roller was set to 1.5, and the peripheral speed ratio between the fourth stretching roller and the fifth stretching roller was set to other than 3.5. As in Example 2, a laminated polyolefin microporous was obtained. Film g.

比較例8 Comparative Example 8

除了將縱向拉伸裝置A之第一拉伸輥與第二拉伸輥之圓周速度比設定為1.3，將第二拉伸輥與第三拉伸輥之圓周速度比設定為1.7，將第三拉伸輥與第四拉伸輥之圓周速度比設定為1.8，將第四拉伸輥與第五拉伸輥之圓周速度比設定為1.9以外，與實施例2相同，得到積層聚烯烴微多孔膜h。 In addition to setting the peripheral speed ratio of the first stretching roller to the second stretching roller of the longitudinal stretching device A to 1.3, the peripheral speed ratio of the second stretching roller to the third stretching roller to 1.7, and the third The peripheral speed ratio between the stretching roller and the fourth stretching roller was set to 1.8, and the peripheral speed ratio between the fourth stretching roller and the fifth stretching roller was set to other than 1.9. In the same manner as in Example 2, a laminated polyolefin microporous material was obtained. Film h.

比較例9 Comparative Example 9

除了僅使用聚乙烯溶液A，以190℃從單層模頭中擠出 而成型膠狀片材，並使用得到之單層膠狀片材以外，與實施例2相同，得到聚烯烴微多孔膜i。 A polyolefin microporous film was obtained in the same manner as in Example 2 except that only the polyethylene solution A was used to extrude a single-layer die at 190 ° C to form a gel-like sheet, and the obtained single-layer gel-like sheet was used. i.

比較例10 Comparative Example 10

除了使用MFR係3.2g/10min之乙烯-1-己烯共聚物作為第二聚乙烯組合物中含有之低熔點樹脂以外，與實施例2相同，得到積層聚烯烴微多孔膜j。 A laminated polyolefin microporous film j was obtained in the same manner as in Example 2 except that an ethylene-1-hexene copolymer of MFR 3.2 g / 10 min was used as the low-melting resin contained in the second polyethylene composition.

比較例11 Comparative Example 11

除了將第一聚乙烯組合物之超高分子量聚乙烯(UHMWPE)與高密度聚乙烯(HDPE)之配混比調整為表1所示以外，與實施例2相同，得到積層聚烯烴微多孔膜k。 A laminated polyolefin microporous membrane was obtained in the same manner as in Example 2 except that the compounding ratio of the ultra high molecular weight polyethylene (UHMWPE) and the high density polyethylene (HDPE) of the first polyethylene composition was adjusted as shown in Table 1. k.

實施例19 Example 19

通過使用圖5所示塗佈裝置(凹版塗佈法)以搬運速度50m/分鐘於實施例1中得到之積層聚烯烴微多孔膜A上塗佈塗佈液(a)，並使其以10秒鐘通過50℃之熱風乾燥爐，從而將其乾燥，得到電池用隔膜。此時，調節塗佈裝置之塗佈輥與支撐輥之位置，使塗佈切線之粗細係3mm至5mm之範圍內。此外，塗佈輥使用直徑100mm且擺動精度係8μm/Φ 100mm之凹版輥。接著，進行縱切加工，得到電池用隔膜之厚度17μm、寬度900mm、捲繞長度5000m之電池用隔膜。 By using a coating apparatus (gravure coating method) shown in FIG. 5, the coating liquid (a) was applied to the laminated polyolefin microporous film A obtained in Example 1 at a conveying speed of 50 m / min, and the coating liquid (a) was applied at a speed of 10 m / min. It was passed through a hot air drying oven at 50 ° C for 2 seconds to dry it to obtain a battery separator. At this time, adjust the positions of the coating roller and the support roller of the coating device so that the thickness of the coating tangent is within a range of 3 mm to 5 mm. In addition, as the coating roller, a gravure roller having a diameter of 100 mm and a swing accuracy of 8 μm / Φ 100 mm was used. Next, a slitting process was performed to obtain a battery separator having a thickness of 17 μm, a width of 900 mm, and a winding length of 5000 m.

實施例20至實施例36 Examples 20 to 36

除了使用實施例2至實施例18中得到之積層聚烯烴微多孔膜B至積層聚烯烴微多孔膜R以外，與實施例19相同，得到電池用隔膜。 A separator for a battery was obtained in the same manner as in Example 19, except that the laminated polyolefin microporous film B to the laminated polyolefin microporous film R obtained in Examples 2 to 18 were used.

實施例37 Example 37

除了將塗佈液(a)替換成塗佈液(b)以外，與實施例20相同，得到電池用隔膜。 A battery separator was obtained in the same manner as in Example 20 except that the coating solution (a) was replaced with the coating solution (b).

實施例38 Example 38

除了將塗佈液(a)替換成塗佈液(c)以外，與實施例20相同，得到電池用隔膜。 A battery separator was obtained in the same manner as in Example 20 except that the coating liquid (a) was replaced with the coating liquid (c).

實施例39 Example 39

除了塗佈輥使用直徑100mm且擺動精度係10μm/Φ 100mm之凹版輥以外，與實施例20相同，得到電池用隔膜。 A battery separator was obtained in the same manner as in Example 20 except that a gravure roll having a diameter of 100 mm and a swing accuracy of 10 μm / Φ 100 mm was used as the coating roll.

實施例40 Example 40

除了塗佈輥使用直徑100mm且擺動精度係5μm/Φ 100mm之凹版輥以外，與實施例20相同，得到電池用隔膜。 A battery separator was obtained in the same manner as in Example 20, except that a gravure roll having a diameter of 100 mm and a swing accuracy of 5 μm / Φ 100 mm was used as the coating roll.

實施例41 Example 41

除了調節塗佈裝置之凹版輥與支撐輥之位置，將塗佈切線之粗細設為5至7mm之範圍以外，與實施例20相同，得到電池用隔膜。 A battery separator was obtained in the same manner as in Example 20, except that the positions of the gravure roll and the support roll of the coating device were adjusted and the thickness of the coating tangent line was set to a range of 5 to 7 mm.

實施例42 Example 42

除了調節塗佈裝置之凹版輥與支撐輥之位置，將塗佈切線之粗細設為8至10mm之範圍以外，與實施例20相同，得到電池用隔膜。 A battery separator was obtained in the same manner as in Example 20, except that the positions of the gravure roll and the support roll of the coating device were adjusted and the thickness of the coating tangent line was set to a range of 8 to 10 mm.

實施例43 Example 43

除了變更塗佈裝置之凹版輥之稱重感應器容量，將多孔層厚度設為5μm以外，與實施例20相同，得到電池用隔膜。 A separator for a battery was obtained in the same manner as in Example 20 except that the capacity of the load cell of the gravure roll of the coating apparatus was changed and the thickness of the porous layer was 5 μm.

實施例44 Example 44

除了調節塗佈裝置之凹版輥與支撐輥之位置，將塗佈切線之粗細設為11mm至13mm之範圍以外，與實施例20相同，得到電池用隔膜。 A battery separator was obtained in the same manner as in Example 20, except that the positions of the gravure roll and the support roll of the coating device were adjusted and the thickness of the coating tangent line was set to a range of 11 mm to 13 mm.

實施例45 Example 45

除了塗佈輥使用直徑100mm且擺動精度係12μm/Φ 100mm之凹版輥以外，與實施例20相同，得到電池用隔膜。 A separator for a battery was obtained in the same manner as in Example 20, except that a gravure roll having a diameter of 100 mm and a swing accuracy of 12 μm / Φ 100 mm was used as the coating roll.

實施例46 Example 46

除了變更塗佈裝置之凹版輥之稱重感應器容量，使多孔層厚度為8μm以外，與實施例20相同，得到電池用隔膜。 A separator for a battery was obtained in the same manner as in Example 20, except that the capacity of the load cell of the gravure roll of the coating apparatus was changed so that the thickness of the porous layer was 8 μm.

比較例12至比較例22 Comparative Example 12 to Comparative Example 22

除了使用比較例1至比較例11中得到之積層聚烯烴微多孔膜a至積層聚烯烴微多孔膜k以外，與實施例19相同，得到電池用隔膜。 A battery separator was obtained in the same manner as in Example 19, except that the laminated polyolefin microporous film a to the laminated polyolefin microporous film k obtained in Comparative Examples 1 to 11 were used.

表1示出實施例1至18之積層聚烯烴微多孔膜之製造條件，表2示出比較例1至比較例11之積層聚烯烴微多孔膜之製造條件。 Table 1 shows the manufacturing conditions of the laminated polyolefin microporous films of Examples 1 to 18, and Table 2 shows the manufacturing conditions of the laminated polyolefin microporous films of Comparative Examples 1 to 11.

表3示出實施例19至實施例46之電池用隔膜之製造條件、電池用隔膜之特性及其捲繞體之特性，表4示出比較例12至比較例22之電池用隔膜之製造條件、電池用隔膜之特性及其捲繞體之特性。 Table 3 shows the manufacturing conditions of the battery separators of Examples 19 to 46, the characteristics of the battery separators, and the characteristics of the wound body. Table 4 shows the manufacturing conditions of the battery separators of Comparative Examples 12 to 22. 2. The characteristics of battery separators and the characteristics of the wound body.

Claims (12)

一種積層聚烯烴微多孔膜，其長度為1000m以上，具有第一聚烯烴微多孔膜與第二聚烯烴微多孔膜，切斷溫度係128℃至135℃，每20μm厚度從30℃至105℃之氣阻度上升率不足1.5sec/100ccAir/℃，長度方向之F25值之變動幅度係1MPa以下，前述F25值表示使用拉伸試驗機將試驗片拉伸25%時之荷載值除以試驗片之剖面積得到之值。     A laminated polyolefin microporous membrane having a length of more than 1000m, having a first polyolefin microporous membrane and a second polyolefin microporous membrane, with a cutting temperature of 128 ° C to 135 ° C and a thickness of 30 ° C to 105 ° C per 20 μm thickness. The air resistance increase rate is less than 1.5sec / 100ccAir / ℃, and the fluctuation range of the F25 value in the length direction is less than 1MPa. The aforementioned F25 value represents the load value when the test piece is stretched by 25% by a tensile tester divided by the test piece. The value obtained from the cross-sectional area.     如請求項1所記載之積層聚烯烴微多孔膜，其中前述第二聚烯烴微多孔膜含有熔體流動速率係25g/10min至150g/10min而熔點係120℃以上且不足130℃之樹脂。     The laminated polyolefin microporous membrane according to claim 1, wherein the second polyolefin microporous membrane contains a resin having a melt flow rate of 25 g / 10 min to 150 g / 10 min and a melting point of 120 ° C or higher and less than 130 ° C.     一種電池用隔膜，其於如請求項1或2所記載之積層聚烯烴微多孔膜之至少單面上設置含有水溶性樹脂或水分散性樹脂及耐熱性顆粒且平均厚度T(ave)係1μm至5μm之多孔層。     A battery separator comprising a laminated polyolefin microporous film according to claim 1 or 2 provided with a water-soluble resin or a water-dispersible resin and heat-resistant particles on at least one side thereof, and having an average thickness T (ave) of 1 μm. Up to 5 μm porous layer.     如請求項3所記載之電池用隔膜，其中前述多孔層之長度方向之厚度變動幅度(R)係1.0μm以下。     The battery separator according to claim 3, wherein the thickness variation range (R) in the longitudinal direction of the porous layer is 1.0 μm or less.     如請求項3或4所記載之電池用隔膜，其中前述水溶性樹脂或前述水分散性樹脂含有聚乙烯醇、丙烯酸系樹脂及聚偏二氟乙烯系樹脂中之至少一種。     The battery separator according to claim 3 or 4, wherein the water-soluble resin or the water-dispersible resin contains at least one of polyvinyl alcohol, an acrylic resin, and a polyvinylidene fluoride resin.     如請求項3至5中任一項所記載之電池用隔膜，其中前述積層聚烯烴微多孔膜之長度係2000m以上。     The battery separator according to any one of claims 3 to 5, wherein the length of the laminated polyolefin microporous membrane is 2000 m or more.     如請求項3至6中任一項所記載之電池用隔膜，其中前述積層聚烯烴微多孔膜之長度係3000m以上。     The battery separator according to any one of claims 3 to 6, wherein the length of the laminated polyolefin microporous membrane is 3000 m or more.     一種積層聚烯烴微多孔膜之製造方法，包括以下製程：(a)於第一聚烯烴組合物中熔融混煉成膜用溶劑而調製出第一聚烯烴溶液之製程；(b)於第二聚烯烴組合物中熔融混煉成膜用溶劑而調製出第二聚烯烴溶液之製程；(c)從1個模頭中同時擠出前述第一聚烯烴溶液及前述第二聚烯烴溶液並進行冷卻而形成未拉伸膠狀片材之製程；(d)使前述未拉伸膠狀片材通過至少3對縱向拉伸輥組間，使各輥間之圓周速度分階段增大，從而沿縱向拉伸，得到縱向拉伸膠狀片材之製程，此處，將縱向拉伸輥及與其平行相接之用耐熱性橡膠被覆之軋輥設為1對縱向拉伸輥組，前述軋輥與前述縱向拉伸輥相接之壓力係0.05MPa以上0.5MPa以下；(e)將前述縱向拉伸膠狀片材以夾鉗間距離於拉幅機出口係50mm以下之方式夾住而沿橫向拉伸，得到雙軸拉伸膠狀片材之製程；(f)從前述雙軸拉伸膠狀片材中提取成膜用溶劑並進行乾燥之製程；以及 (g)對乾燥後之片材進行熱處理而得到積層聚烯烴微多孔膜之製程。     A method for manufacturing a laminated polyolefin microporous membrane includes the following processes: (a) a process for preparing a first polyolefin solution by melt-kneading a film-forming solvent in a first polyolefin composition; (b) a second process A process for preparing a second polyolefin solution by melt-kneading a solvent for forming a polyolefin in a polyolefin composition; (c) simultaneously extruding the first polyolefin solution and the second polyolefin solution from one die and performing A process of cooling to form an unstretched gelatinous sheet; (d) passing the aforementioned unstretched gelatinous sheet through at least three pairs of longitudinally stretched roller groups, so that the peripheral speed between the rollers is increased in stages, so that The process of longitudinally stretching to obtain a longitudinally stretched gelatinous sheet. Here, a longitudinal stretching roll and a heat-resistant rubber-covered roll connected in parallel to the longitudinal stretching roll are set as a pair of longitudinal stretching rolls. The pressure at which the longitudinal stretching rollers are connected is 0.05 MPa to 0.5 MPa; (e) The aforementioned longitudinally stretched gelatinous sheet is clamped in a manner that the distance between the clamps is less than 50 mm from the tenter exit and stretched in the transverse direction. To obtain a biaxially stretched gelatinous sheet; (f) from the aforementioned biaxially stretched glue Forming the sheet with a solvent to extract and dried process; and (g) drying the sheet after the heat treatment process to obtain a laminate of a polyolefin microporous membrane.     如請求項8所記載之積層聚烯烴微多孔膜之製造方法，其中(d)製程之相鄰縱向拉伸輥之圓周速度比分階段地增大。     The method for manufacturing a laminated polyolefin microporous film according to claim 8, wherein the peripheral speed ratio of the adjacent longitudinal stretching rollers in the step (d) is increased in stages.     一種積層聚烯烴微多孔膜捲繞體之製造方法，包括將利用如請求項8或9所記載之積層聚烯烴微多孔膜之製造方法得到之聚烯烴微多孔膜以搬運速度50m/分鐘以上捲繞至捲繞芯上之製程。     A method for manufacturing a laminated polyolefin microporous film roll, comprising rolling a polyolefin microporous film obtained by using the method for manufacturing a laminated polyolefin microporous film according to claim 8 or 9 at a conveying speed of 50 m / min or more. The process of winding onto a winding core.     一種電池用隔膜之製造方法，包括於如請求項1或2所記載之積層聚烯烴微多孔膜之至少單面上、或者利用如請求項8或9所記載之積層聚烯烴微多孔膜之製造方法得到之積層聚烯烴微多孔膜之至少單面上，以使用擺動精度係10μm/Φ 100mm以下之塗佈輥之輥塗佈法塗佈含有水溶性樹脂或水分散性樹脂及耐熱性顆粒之塗佈液，並進行乾燥之製程。     A method for manufacturing a battery separator, comprising manufacturing at least one side of a laminated polyolefin microporous membrane according to claim 1 or 2 or using the laminated polyolefin microporous membrane according to claim 8 or 9 The at least one side of the laminated polyolefin microporous film obtained by the method is coated by a roll coating method using a coating roller with a swing accuracy of 10 μm / Φ 100 mm or less, and a coating containing a water-soluble resin or a water-dispersible resin and heat-resistant particles is applied. The coating liquid is dried.     如請求項11所記載之電池用隔膜之製造方法，其中前述塗佈輥係凹版輥。     The method for producing a battery separator according to claim 11, wherein the coating roll is a gravure roll.