JP2657434B2 - Polyethylene microporous membrane, method for producing the same, and battery separator using the same - Google Patents
Polyethylene microporous membrane, method for producing the same, and battery separator using the sameInfo
- Publication number
- JP2657434B2 JP2657434B2 JP20474991A JP20474991A JP2657434B2 JP 2657434 B2 JP2657434 B2 JP 2657434B2 JP 20474991 A JP20474991 A JP 20474991A JP 20474991 A JP20474991 A JP 20474991A JP 2657434 B2 JP2657434 B2 JP 2657434B2
- Authority
- JP
- Japan
- Prior art keywords
- weight
- polyethylene
- molecular weight
- microporous
- composition
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/18—Manufacture of films or sheets
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
- C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
- C08J2323/04—Homopolymers or copolymers of ethene
- C08J2323/06—Polyethene
Description
【０００１】[0001]
【産業上の利用分野】本発明は、ポリエチレン微多孔
膜、その製造方法及びそれを用いた電池用セパレータに
関し、特に透過性能及び機械的強度に優れるとともに、
低温で透過性を遮断する機能を有するポリエチレン微多
孔膜、その製造方法及びそれを用いた電池用セパレータ
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microporous polyethylene membrane, a method for producing the same, and a battery separator using the same.
The present invention relates to a microporous polyethylene membrane having a function of blocking permeability at a low temperature, a method for producing the same, and a battery separator using the same.
【０００２】[0002]
【従来の技術及び発明が解決しようとする課題】微多孔
膜は、電池用セパレーター、電解コンデンサー用隔膜、
各種フィルター、透湿防水衣料、逆浸透濾過膜、限外濾
過膜、精密濾過膜等の各種用途に用いられている。2. Description of the Related Art Microporous membranes include separators for batteries, diaphragms for electrolytic capacitors,
It is used for various applications such as various filters, moisture-permeable waterproof clothing, reverse osmosis filtration membranes, ultrafiltration membranes, and microfiltration membranes.
【０００３】従来、ポリオレフィン微多孔膜の製造方法
としては、例えば異種ポリマー等の微粉体からなる孔形
成剤をポリオレフィンに混合してミクロ分散させた後、
孔形成剤を抽出する混合抽出法、ポリオレフィン相を溶
媒でミクロ相分離することにより多孔構造とする相分離
法、異種固体がミクロ分散しているポリオレフィン成形
体に延伸などの歪を与えることにより、異種固体間を界
面破壊して空孔を生じさせて多孔化する延伸法などが用
いられている。しかし、これらの方法では通常分子量が
50万未満程度のポリオレフィンが用いられるため、延伸
による薄膜化及び高強度化には限界があった。[0003] Conventionally, as a method for producing a microporous polyolefin membrane, for example, a pore-forming agent composed of fine powder of a different polymer or the like is mixed with polyolefin and micro-dispersed.
A mixed extraction method for extracting a pore-forming agent, a phase separation method for forming a porous structure by separating a polyolefin phase into a microphase with a solvent, and applying a strain such as stretching to a polyolefin molded article in which different solids are micro-dispersed, An elongation method or the like has been used in which a heterogeneous solid is broken down at the interface to generate pores and make the pores porous. However, in these methods, the molecular weight is usually
Since a polyolefin of less than about 500,000 is used, there is a limit to thinning and high strength by stretching.
【０００４】最近、高強度及び高弾性のフィルムに成形
し得る超高分子量ポリオレフィンが開発され、これによ
る高強度の微多孔膜の製造が種々提案された。例えば特
開昭58-5228 号は、超高分子量ポリオレフィンを不揮発
性溶媒に溶解し、この溶液から繊維またはフィルムなど
のゲルを成形し、この溶媒を含むゲルを揮発性溶剤で抽
出処理した後、加熱延伸する方法を開示している。しか
しながら、不揮発性溶媒で高度に膨潤した多孔性組織を
有するゲルは、２方向に延伸しようとしても、高配向の
延伸ができず、網状組織の拡大により破断し易く、得ら
れるフィルムは強度が小さく、また形成される孔径分布
が大きくなるという欠点があった。一方不揮発性溶媒を
揮発性溶剤で抽出した後に乾燥したゲルは、網状組織が
収縮緻密化するが、揮発性溶剤の不均一な蒸発によりフ
ィルム原反にそりが発生し易く、また収縮緻密化によ
り、高倍率の延伸ができないという欠点があった。Recently, ultrahigh molecular weight polyolefins that can be formed into high-strength and high-elastic films have been developed, and various productions of high-strength microporous membranes have been proposed. For example, JP-A-58-5228 discloses that an ultrahigh molecular weight polyolefin is dissolved in a non-volatile solvent, a gel such as a fiber or a film is formed from the solution, and the gel containing the solvent is extracted with a volatile solvent. A method of heating and stretching is disclosed. However, a gel having a porous structure highly swollen with a non-volatile solvent cannot be stretched in a high orientation even if it is stretched in two directions, and is easily broken due to expansion of a network structure, and the obtained film has low strength. In addition, there is a disadvantage that the pore size distribution to be formed becomes large. On the other hand, in the gel dried after extracting the non-volatile solvent with the volatile solvent, the network structure shrinks and densifies, but the non-uniform evaporation of the volatile solvent easily causes warpage of the film raw material, and the shrinking and densification causes However, there is a drawback that stretching at a high magnification cannot be performed.
【０００５】これに対し、重量平均分子量が、７×105
以上の超高分子量ポリオレフィンを溶媒中で加熱溶解し
た溶液からゲル状シートを成形し、前記ゲル状シート中
の溶媒量を脱溶媒処理により調製し、次いで加熱延伸し
た後、残留溶媒を除去することにより、超高分子量ポリ
オレフィン( ポリエチレン）の微多孔膜を製造する方法
が種々提案されている（特開昭60-242035 号、特開昭61
-495132 号、特開昭61-195133 号、特開昭63-39602号、
特開昭63-273651 号）。On the other hand, the weight average molecular weight is 7 × 10 5
Forming a gel-like sheet from a solution obtained by heating and dissolving the above ultra-high molecular weight polyolefin in a solvent, preparing a solvent amount in the gel-like sheet by desolvation treatment, and then heating and stretching to remove a residual solvent. Various methods for producing microporous membranes of ultra-high molecular weight polyolefin (polyethylene) have been proposed (JP-A-60-242035, JP-A-61-21).
-495132, JP-A-61-195133, JP-A-63-39602,
JP-A-63-273651).
【０００６】しかしながら、上記超高分子量ポリオレフ
ィン（ポリエチレン）微多孔膜の製造方法では、いずれ
も超高分子量ポリオレフィンを２軸延伸するために、ま
ずポリオレフィンのある程度希薄な溶液を調製ので、こ
のため得られた溶液は、シート成形するダイス出口でス
ウェルやネックインが大きく、シート成形が困難であ
る。さらにシート中には、溶媒が過剰に含まれているた
め、そのまま延伸しても目的の微多孔膜は得られないの
で脱溶媒処理してシート中の溶媒量を調整する必要があ
る等、多量の溶剤を必要とし、生産性においても問題が
あった。そこで延伸性を損なうことなく、超高分子量ポ
リオレフィンの高濃度溶液からポリオレフィン微多孔膜
を製造することが望まれるようになった。However, in the above-mentioned method for producing a microporous ultrahigh molecular weight polyolefin (polyethylene) film, in order to biaxially stretch the ultrahigh molecular weight polyolefin, a dilute solution of the polyolefin is first prepared to some extent. The resulting solution has a large swell and neck-in at the exit of the die for forming the sheet, and it is difficult to form the sheet. Further, since the sheet contains an excessive amount of solvent, the desired microporous membrane cannot be obtained even if it is stretched as it is, so it is necessary to remove the solvent and adjust the amount of solvent in the sheet. Solvent, and there was also a problem in productivity. Therefore, it has been desired to produce a microporous polyolefin membrane from a high-concentration solution of an ultrahigh molecular weight polyolefin without deteriorating the stretchability.
【０００７】このような問題を解決することを目的とし
て、本発明者らは、超高分子量ポリオレフィンを含有
し、（重量平均分子量／数平均分子量）の値が特定の範
囲内にある組成物を用いたポリオレフィン微多孔膜の製
造方法を提案した（特開平3-64334 号) 。この方法によ
り、延伸性が良好で、高濃度溶液とすることが可能なポ
リオレフィン組成物からポリオレフィン微多孔膜を製造
することが可能となった。In order to solve such a problem, the present inventors have developed a composition containing an ultrahigh molecular weight polyolefin and having a value of (weight average molecular weight / number average molecular weight) within a specific range. A method for producing a microporous polyolefin membrane used was proposed (Japanese Patent Application Laid-Open No. 3-64334). By this method, it has become possible to produce a microporous polyolefin membrane from a polyolefin composition which has good stretchability and can be made into a high-concentration solution.
【０００８】ところで、上記ポリオレフィン微多孔膜を
電池、例えばリチウム電池用セパレータ等に用いる場合
には、電極が短絡して電池内部の温度が上昇した時に、
発火等の事故が生じるのを防止する必要がある。このた
め、リチウムの発火以前に溶解してその孔を目詰りさ
せ、電流をシャットダウンさせる機能をセパレータに持
たせる必要がある。ところが上記各微多孔膜においては
微多孔の閉塞による透過性遮断温度が安全性の点で必ず
しも十分に低いものではなく、より一層安全性を向上さ
せるためには、さらに低い温度で電流のシャットダウン
を起こすセパレータとすることが望ましい。When the above-mentioned microporous polyolefin membrane is used for a battery, for example, a separator for a lithium battery, when the electrodes are short-circuited and the temperature inside the battery rises,
It is necessary to prevent fires and other accidents from occurring. For this reason, it is necessary to provide the separator with a function of dissolving it before the ignition of lithium, clogging the hole, and shutting down the current. However, in each of the above microporous membranes, the permeability cutoff temperature due to microporous occlusion is not necessarily sufficiently low in terms of safety, and in order to further improve safety, the current must be shut down at a lower temperature. It is desirable to use a separator for raising.
【０００９】したがって本発明の目的は、透過性能及び
機械的強度に優れるとともに、低温で透過性が遮断する
機能を有するポリエチレン微多孔膜を提供することであ
る。Accordingly, an object of the present invention is to provide a microporous polyethylene membrane having excellent permeability and mechanical strength, and having a function of blocking permeability at low temperatures.
【００１０】また本発明のもう一つの目的は、上記ポリ
エチレン微多孔膜を効率良く製造する方法を提供するこ
とである。Another object of the present invention is to provide a method for efficiently producing the above polyethylene microporous membrane.
【００１１】さらに、本発明のもう一つの目的は、上記
ポリエチレン微多孔膜を用いた電池用セパレータを提供
することである。Still another object of the present invention is to provide a battery separator using the above microporous polyethylene membrane.
【００１２】[0012]
【課題を解決するための手段】上記目的に鑑み鋭意研究
の結果、本発明者は、超高分子量ポリエチレンと、高密
度ポリエチレンと、低密度ポリエチレンとを含有する組
成物からなるポリエチレン微多孔膜は、透過性能及び機
械的強度に優れるとともに、低温で透過性が遮断するこ
とを見出した。また本発明者らは、超高分子量ポリエチ
レンと、低密度ポリエチレンとを含有する組成物からな
るポリエチレン微多孔膜もほぼ同様の性能を有すること
を見出した。以上に基づき本発明に想到した。Means for Solving the Problems As a result of intensive studies in view of the above objects, the present inventors have found that a microporous polyethylene membrane comprising a composition containing ultrahigh molecular weight polyethylene, high density polyethylene and low density polyethylene is It has been found that it has excellent permeability and mechanical strength, and that the permeability is blocked at a low temperature. The present inventors have also found that a microporous polyethylene membrane comprising a composition containing ultrahigh molecular weight polyethylene and low density polyethylene has almost the same performance. The present invention has been made based on the above.
【００１３】すなわち、本発明の第一のポリエチレン微
多孔膜は、重量平均分子量が７×105 以上の超高分子量
ポリエチレン１〜69重量％と、高密度ポリエチレン98〜
１重量％と、低密度ポリエチレン１〜30重量％とを含有
し、前記超高分子量ポリエチレンと、高密度ポリエチレ
ンとを含有する成分の重量平均分子量／数平均分子量が
10〜300 である組成物からなり、厚さが 0.1〜50μｍ、
空孔率が35〜95％、平均貫通孔径が 0.001〜１μｍ、引
張破断強度が200kg/cm2 以上であり、透過性遮断温度が
135 ℃未満であることを特徴とする。That is, the first microporous polyethylene membrane of the present invention comprises 1 to 69% by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 7 × 10 5 or more, and 98 to 98% of high density polyethylene.
1% by weight and 1 to 30% by weight of low-density polyethylene, and the weight-average molecular weight / number-average molecular weight of the component containing the ultra-high-molecular-weight polyethylene and the high-density polyethylene is:
Consisting of a composition having a thickness of 0.1 to 50 μm,
The porosity is 35 ~ 95%, the average through hole diameter is 0.001 ~ 1μm, the tensile breaking strength is 200kg / cm 2 or more, and the permeability blocking temperature is
It is characterized by being less than 135 ° C.
【００１４】また本発明の第二のポリエチレン微多孔膜
は、重量平均分子量が７×105 以上の超高分子量ポリエ
チレン30〜90重量％と、低密度ポリエチレン70〜10重量
％とを含有する組成物からなり、厚さが 0.1〜50μｍ、
空孔率が35〜95％、平均貫通孔径が 0.001〜１μｍ、引
張破断強度が200kg/cm2以上であり、透過性遮断温度が1
35 ℃未満であることを特徴とする。The second microporous polyethylene membrane of the present invention has a composition containing 30 to 90% by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 7 × 10 5 or more and 70 to 10% by weight of low density polyethylene. Object, thickness is 0.1 ~ 50μm,
The porosity is 35-95%, the average through-hole diameter is 0.001-1 μm, the tensile strength at break is 200 kg / cm 2 or more, and the permeability cutoff temperature is 1
It is characterized by being below 35 ° C.
【００１５】上記第一のポリエチレン微多孔膜を製造す
る本発明の方法は、重量平均分子量が７×105 以上の超
高分子量ポリエチレン１〜69重量％と、高密度ポリエチ
レン98〜１重量％と、低密度ポリエチレン１〜30重量％
とを含有し、前記超高分子量ポリエチレンと、高密度ポ
リエチレンとを含有する成分の重量平均分子量／数平均
分子量が10〜300 である組成物10〜50重量％と、溶媒50
〜90重量％とからなる溶液を調製し、前記溶液をダイよ
り押出し、冷却してゲル状組成物を形成し、前記ゲル状
組成物を前記ポリエチレン組成物の融点＋10℃以下の温
度で延伸し、しかる後残存溶媒を除去することを特徴と
する。The method of the present invention for producing the first microporous polyethylene membrane comprises the steps of: 1 to 69% by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 7 × 10 5 or more; 98 to 1% by weight of high density polyethylene. Low-density polyethylene 1-30% by weight
A composition comprising 10 to 50% by weight of a component containing the ultrahigh molecular weight polyethylene and the high density polyethylene, wherein the weight average molecular weight / number average molecular weight is 10 to 300;
~ 90% by weight of the solution is prepared, the solution is extruded from a die, cooled to form a gel-like composition, and the gel-like composition is stretched at a temperature not higher than the melting point of the polyethylene composition + 10 ° C. Thereafter, the remaining solvent is removed.
【００１６】また上記第二のポリエチレン微多孔膜を製
造する本発明の方法は、重量平均分子量が７×105 以上
の超高分子量ポリエチレン30〜90重量％と、低密度ポリ
エチレン70〜10重量％とを含有し、前記超高分子量ポリ
エチレンと、高密度ポリエチレンとからなる組成物10〜
50重量％と、溶媒50〜90重量％とからなる溶液を調製
し、前記溶液をダイより押出し、冷却してゲル状組成物
を形成し、前記ゲル状組成物を前記ポリエチレン組成物
の融点＋10℃以下の温度で延伸し、しかる後残存溶媒を
除去することを特徴とする。Further, the method of the present invention for producing the second microporous polyethylene membrane comprises 30 to 90% by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 7 × 10 5 or more, and 70 to 10% by weight of low density polyethylene. And the composition comprising the ultrahigh molecular weight polyethylene and high density polyethylene 10 to
A solution consisting of 50% by weight and a solvent of 50 to 90% by weight is prepared, the solution is extruded from a die, cooled to form a gel composition, and the gel composition is melted at a melting point of the polyethylene composition +10. It is characterized in that the film is stretched at a temperature of not more than ° C., and thereafter the residual solvent is removed.
【００１７】さらに本発明の電池用セパレータは、上記
第一又は第二のポリエチレン微多孔膜からなることを特
徴とする。Further, the battery separator of the present invention is characterized by comprising the first or second microporous polyethylene membrane.
【００１８】本発明を以下詳細に説明する。まず本発明
の第一のポリエチレン微多孔膜を形成する組成物につい
て説明する。本発明の第一のポリエチレン微多孔膜は、
重量平均分子量が７×105 以上の超高分子量ポリエチレ
ン１〜69重量％と、高密度ポリエチレン98〜１重量％
と、低密度ポリエチレン１〜30重量％とを含有し、前記
超高分子量ポリエチレンと、高密度ポリエチレンとを含
有する成分の重量平均分子量／数平均分子量が10〜300
である組成物からなる。The present invention will be described in detail below. First, the composition for forming the first microporous polyethylene membrane of the present invention will be described. The first polyethylene microporous membrane of the present invention,
1 to 69% by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 7 × 10 5 or more and 98 to 1% by weight of high density polyethylene
And low-density polyethylene in an amount of 1 to 30% by weight, and the component containing the ultrahigh-molecular-weight polyethylene and the high-density polyethylene has a weight average molecular weight / number average molecular weight of 10 to 300.
Consisting of a composition
【００１９】上記超高分子量ポリエチレンは、重量平均
分子量が７×105 以上、好ましくは１×106 〜15×106
のものである。重量平均分子量が７×105 未満では、最
大延伸倍率が低く、目的の微多孔膜が得られない。一
方、上限は特に限定的ではないが15×106 を超えるもの
は、ゲル状成形物の形成において、成形性に劣る。上記
超高分子量ポリエチレンの密度は、通常0.93〜0.95g/cm
3 程度である。The ultrahigh molecular weight polyethylene has a weight average molecular weight of 7 × 10 5 or more, preferably 1 × 10 6 to 15 × 10 6.
belongs to. If the weight average molecular weight is less than 7 × 10 5 , the maximum draw ratio is low, and the desired microporous membrane cannot be obtained. On the other hand, the upper limit is not particularly limited, but those exceeding 15 × 10 6 are inferior in moldability in forming a gel-like molded product. The density of the ultra high molecular weight polyethylene is usually 0.93 to 0.95 g / cm
About three .
【００２０】また本発明において高密度ポリエチレンと
は、通常密度0.935 g/cm3 以上のポリエチレンである。
またその重量平均分子量は７×105 未満のものである
が、分子量の下限としては１×104 以上のものが好まし
い。重量平均分子量が１×104未満では延伸時に破断が
起こりやすくなるため好ましくない。特に重量平均分子
量１×105 以上７×105 未満のものが好ましい。In the present invention, the high-density polyethylene is usually polyethylene having a density of 0.935 g / cm 3 or more.
The weight average molecular weight is less than 7 × 10 5 , but the lower limit of the molecular weight is preferably 1 × 10 4 or more. If the weight-average molecular weight is less than 1 × 10 4, it is not preferred because breakage tends to occur during stretching. Particularly, those having a weight average molecular weight of 1 × 10 5 or more and less than 7 × 10 5 are preferable.
【００２１】さらに本発明において低密度ポリエチレン
としては、高圧法による分枝状ポリエチレン（ＬＤＰ
Ｅ）及び低圧法による直鎖状の低密度ポリエチレン（Ｌ
ＬＤＰＥ）が挙げられる。Further, in the present invention, the low-density polyethylene is a branched polyethylene (LDP) obtained by a high-pressure method.
E) and a linear low-density polyethylene (L
LDPE).
【００２２】ＬＤＰＥの場合、その密度は、通常0.91〜
0.93g/cm3 程度であり、またそのメルトインデックス(M
I 190 ℃、2.16 kg 荷重) は、0.1 〜20ｇ/10 分である
のが好ましく、より好ましくは、0.5 〜10ｇ/10 分であ
る。In the case of LDPE, the density is usually from 0.91 to
0.93 g / cm 3 and its melt index (M
(I 190 ° C, 2.16 kg load) is preferably 0.1 to 20 g / 10 min, more preferably 0.5 to 10 g / 10 min.
【００２３】ＬＬＤＰＥの場合、その密度は、通常0.91
〜0.93g/cm3 程度であり、またそのメルトインデックス
(MI 、190 ℃、2.16 kg 荷重) は、0.1 〜25ｇ/10 分で
あるのが好ましく、より好ましくは、0.5 〜10ｇ/10 分
である。In the case of LLDPE, its density is usually 0.91
Is a ~0.93g / cm 3 or so, also the melt index
(MI, 190 ° C, 2.16 kg load) is preferably 0.1 to 25 g / 10 min, more preferably 0.5 to 10 g / 10 min.
【００２４】上述したような各種成分の配合割合は、超
高分子量ポリエチレンが１〜69重量％、好ましくは５〜
30重量％であり、高密度ポリエチレンが98〜１重量％、
好ましくは93〜50重量％であり、低密度ポリエチレンが
１〜30重量％、好ましくは２〜20重量％である。The proportion of the various components as described above is such that the ultrahigh molecular weight polyethylene is 1 to 69% by weight, preferably 5 to 69% by weight.
30% by weight, 98-1% by weight of high density polyethylene,
Preferably, it is 93 to 50% by weight, and the low density polyethylene is 1 to 30% by weight, preferably 2 to 20% by weight.
【００２５】超高分子量ポリエチレンが１重量％未満で
は延伸性の向上に寄与する超高分子量ポリエチレンの分
子鎖の絡み合いがほとんど形成されず、高強度の微多孔
膜を得ることができない。一方、69重量％を超えるとポ
リエチレン組成物の溶液の高濃度化の達成が困難とな
る。また高密度ポリエチレンが１重量％未満ではポリエ
チレン組成物の高濃度化の達成が困難であり、98重量％
を超えると超高分子量ポリエチレンが少なく、高強度の
微多孔膜を得ることができない。さらに低密度ポリエチ
レン (ＬＤＰＥ又はＬＬＤＰＥ）が１重量％未満では、
微多孔膜の低温 (135 ℃未満、好ましくは100〜130 ℃)
での透過性遮断が達成されず、また30重量％を超える
と延伸してもラメラ間の開裂が生じず、微多孔が形成さ
れにくくなり、透過性及び機械的強度が十分でなくな
る。When the ultra-high molecular weight polyethylene is less than 1% by weight, the entanglement of the molecular chains of the ultra-high molecular weight polyethylene which contributes to the improvement of stretchability is hardly formed, and a high-strength microporous film cannot be obtained. On the other hand, if it exceeds 69% by weight, it is difficult to achieve a high concentration of the solution of the polyethylene composition. If the high-density polyethylene is less than 1% by weight, it is difficult to achieve a high concentration of the polyethylene composition, and 98% by weight
If it exceeds, the amount of ultrahigh molecular weight polyethylene is small, and a high-strength microporous membrane cannot be obtained. Furthermore, if the low-density polyethylene (LDPE or LLDPE) is less than 1% by weight,
Low temperature of microporous membrane (less than 135 ° C, preferably 100-130 ° C)
When the content exceeds 30% by weight, cleavage between the lamellas does not occur even when the film is stretched, micropores are hardly formed, and the permeability and mechanical strength are insufficient.
【００２６】ただし、上記構成成分のうち超高分子量ポ
リエチレン及び高密度ポリエチレンについては、両者を
組成物とした時の重量平均分子量／数平均分子量が10〜
300、好ましくは12〜 250である必要がある。重量平均
分子量／数平均分子量が10未満では、平均分子鎖長が大
きく、溶解時の分子鎖同志の絡み合い密度が高くなるた
め、高濃度溶液の調製が困難である。また300 を超える
と、延伸時に低分子量成分の破断が起こり膜全体の強度
が低下する。However, among the above components, ultrahigh molecular weight polyethylene and high density polyethylene have a weight average molecular weight / number average molecular weight of 10 to 10 when both are used as a composition.
It should be 300, preferably 12-250. If the weight-average molecular weight / number-average molecular weight is less than 10, the average molecular chain length is large and the entanglement density of the molecular chains during dissolution is high, so that it is difficult to prepare a high-concentration solution. On the other hand, when it exceeds 300, the low molecular weight component is broken at the time of stretching, and the strength of the whole film decreases.
【００２７】なお、重量平均分子量／数平均分子量は、
分子量分布の尺度として用いられるものであり、この分
子量の比が大きくなるほど分子量分布の幅は拡大する。
すなわち重量平均分子量の異なるポリエチレンからなる
組成物においては、組成物の分子量の比が大きいほど、
配合するポリエチレンの重量平均分子量の差が大きく、
また小さいほど重量平均分子量の差が小さいことを示し
ている。The weight-average molecular weight / number-average molecular weight is:
It is used as a measure of the molecular weight distribution, and the width of the molecular weight distribution increases as the ratio of the molecular weights increases.
That is, in a composition composed of polyethylene having different weight average molecular weights, as the ratio of the molecular weights of the composition is larger,
The difference in weight average molecular weight of polyethylene to be compounded is large,
The smaller the weight average molecular weight, the smaller the difference.
【００２８】このような超高分子量ポリエチレンと、高
密度ポリエチレンとは、重量平均分子量が７×105 以上
の超高分子量ポリエチレンと、重量平均分子量が７×10
5 未満の高密度ポリエチレンとを重量平均分子量／数平
均分子量が上記範囲となるように適量混合することによ
って得ることができる。Such an ultrahigh molecular weight polyethylene and a high density polyethylene include an ultrahigh molecular weight polyethylene having a weight average molecular weight of 7 × 10 5 or more and a weight average molecular weight of 7 × 10 5
It can be obtained by mixing an appropriate amount with a high-density polyethylene of less than 5 so that the weight average molecular weight / number average molecular weight falls within the above range.
【００２９】なお、本発明においては上記超高分子量ポ
リエチレンと高密度ポリエチレンとからなる組成物とし
て、多段重合高密度ポリエチレンも用いることができ
る。ただし、上記多段重合ポリエチレンは、重量平均分
子量が７×105 以上の成分と、重量平均分子量が７×10
5 未満の成分とが、上記分子量分布の関係を満たすとと
もに、重量平均分子量が７×105 以上の成分を１〜69重
量％含有するように重合したものである必要がある。多
段重合ポリエチレンを用いる場合、重量平均分子量が７
×105 以上の成分と、重量平均分子量が７×105 未満の
成分とが、それぞれ上記組成物における超高分子量ポリ
エチレンと、高密度ポリエチレンとに該当するように、
その配合割合を設定すればよい。In the present invention, multi-stage polymerized high-density polyethylene can also be used as the composition comprising the ultrahigh molecular weight polyethylene and the high-density polyethylene. However, the multi-stage polymerized polyethylene has a component having a weight average molecular weight of 7 × 10 5 or more and a weight average molecular weight of 7 × 10 5
Less than 5 components and, together with satisfying the relation of the molecular weight distribution, it is necessary that those polymerized so that the weight average molecular weight of the 7 × 10 5 or more components containing 1 to 69 wt%. When multi-stage polymerized polyethylene is used, the weight average molecular weight is 7
× 10 5 or more components, and the component having a weight average molecular weight of less than 7 × 10 5 respectively, so as to correspond to ultra-high molecular weight polyethylene and high-density polyethylene in the composition,
What is necessary is just to set the compounding ratio.
【００３０】次に本発明の第二の微多孔膜を形成する組
成物について説明する。本発明の第二のポリエチレン微
多孔膜は、重量平均分子量が７×105 以上の超高分子量
ポリエチレン30〜90重量％と、低密度ポリエチレン70〜
10重量％とからなる組成物からなる。Next, the composition for forming the second microporous membrane of the present invention will be described. The second microporous polyethylene membrane of the present invention has an ultrahigh molecular weight polyethylene having a weight average molecular weight of 7 × 10 5 or more, 30 to 90% by weight, and a low density polyethylene 70 to 90%.
10% by weight.
【００３１】上記超高分子量ポリエチレンは、上述した
第一の微多孔膜用の組成物と同様のものを用いることが
できる。As the ultrahigh molecular weight polyethylene, the same one as the above-mentioned composition for the first microporous membrane can be used.
【００３２】また低密度ポリエチレンも、上述した第一
の微多孔膜用の組成物と同様のものを用いることができ
る。The same low-density polyethylene as the above-described composition for the first microporous membrane can be used.
【００３３】上述したような超高分子量ポリエチレン
と、低密度ポリエチレンとの配合割合は、超高分子量ポ
リエチレンが30〜90重量％、好ましくは40〜80重量％で
あり、低密度ポリエチレンが70〜10重量％、好ましくは
60〜20重量％である。The blending ratio of the ultrahigh molecular weight polyethylene and the low density polyethylene as described above is such that the ultrahigh molecular weight polyethylene is 30 to 90% by weight, preferably 40 to 80% by weight, and the low density polyethylene is 70 to 10% by weight. % By weight, preferably
It is 60 to 20% by weight.
【００３４】超高分子量ポリエチレンが30重量％未満で
は (低密度ポリエチレンが70重量％を超えると) 、延伸
してもラメラ間の開裂が生じず、微多孔が形成されにく
くなり、透過機能と機械的強度が十分でなくなり、また
超高分子量ポリエチレンが90重量％を超えると (低密度
ポリエチレンが10重量％未満では) 、ポリエチレン組成
物の高濃度化の達成が困難となる。ゆえに目的とする低
温 (135 ℃未満、好ましくは90〜130 ℃) で透過性を遮
断できるポリエチレン微多孔膜を得ることが困難とな
る。If the ultra-high molecular weight polyethylene is less than 30% by weight (low-density polyethylene exceeds 70% by weight), the lamellar cleavage does not occur even when stretched, microporosity is hardly formed, and the permeability and mechanical properties are poor. If the mechanical strength is insufficient, and if the ultra-high molecular weight polyethylene exceeds 90% by weight (low-density polyethylene is less than 10% by weight), it becomes difficult to achieve a high concentration of the polyethylene composition. Therefore, it becomes difficult to obtain a microporous polyethylene membrane that can block the permeability at the desired low temperature (less than 135 ° C., preferably 90 to 130 ° C.).
【００３５】なお、上述したような第一及び第二のポリ
エチレン微多孔膜用のポリエチレン組成物には、必要に
応じて酸化防止剤、紫外線吸収剤、滑剤、アンチブロッ
キング剤、顔料、染料、無機充填剤などの各種添加剤を
本発明の目的を損なわない範囲で添加することができ
る。The polyethylene composition for the first and second microporous polyethylene membranes described above may optionally contain an antioxidant, an ultraviolet absorber, a lubricant, an antiblocking agent, a pigment, a dye, an inorganic Various additives such as fillers can be added within a range that does not impair the purpose of the present invention.
【００３６】このようなポリエチレン組成物を用いた本
発明のポリエチレン微多孔膜の製造方法について説明す
る。The method for producing the microporous polyethylene membrane of the present invention using such a polyethylene composition will be described.
【００３７】本発明において、原料となるポリエチレン
組成物の溶液は、上述のポリエチレン組成物を溶媒に加
熱溶解することにより調製する。In the present invention, a solution of the polyethylene composition as a raw material is prepared by heating and dissolving the above-described polyethylene composition in a solvent.
【００３８】この溶媒としては、ポリエチレン組成物を
十分に溶解できるものであれば特に限定されない。例え
ば、ノナン、デカン、ウンデカン、ドデカン、パラフィ
ン油などの脂肪族または環式の炭化水素、あるいは沸点
がこれらに対応する鉱油留分などが挙げられるが、溶媒
含有量が安定なゲル状成形物を得るためにはパラフィン
油のような不揮発性の溶媒が好ましい。The solvent is not particularly limited as long as it can sufficiently dissolve the polyethylene composition. For example, nonane, decane, undecane, dodecane, aliphatic or cyclic hydrocarbons such as paraffin oil, or a mineral oil fraction having a boiling point corresponding thereto, and the like. To obtain, a non-volatile solvent such as paraffin oil is preferred.
【００３９】加熱溶解は、ポリエチレン組成物が溶媒中
で完全に溶解する温度で攪拌しながら行う。その温度は
使用する重合体及び溶媒により異なるが、例えば超高分
子量ポリエチレンと高密度ポリエチレンと低密度ポリエ
チレンとからなる組成物 (以後第一のポリエチレン組
成物という。) の場合には140 〜250 ℃の範囲であり、
超高分子量ポリエチレンと低密度ポリエチレンとからな
る組成物 (以後第二のポリエチレン組成物という。) の
場合には140 〜250 ℃の範囲である。また、ポリエチレ
ン組成物溶液の濃度は、第一の組成物の場合10〜50重量
％、好ましくは10〜40重量％であり、また第二の組成物
の場合10〜50重量％、好ましくは10〜30重量％である。
なお、加熱溶解にあたってはポリエチレンの酸化を防止
するために酸化防止剤を添加するのが好ましい。The heating dissolution is carried out with stirring at a temperature at which the polyethylene composition completely dissolves in the solvent. The temperature varies depending on the polymer and solvent used. For example, in the case of a composition comprising ultra-high molecular weight polyethylene, high-density polyethylene and low-density polyethylene (hereinafter referred to as the first polyethylene composition), 140 to 250 ° C. Is the range of
In the case of a composition comprising ultra-high molecular weight polyethylene and low density polyethylene (hereinafter referred to as a second polyethylene composition), the temperature is in the range of 140 to 250 ° C. The concentration of the polyethylene composition solution is 10 to 50% by weight, preferably 10 to 40% by weight for the first composition, and 10 to 50% by weight, preferably 10 to 50% by weight for the second composition. ~ 30% by weight.
In addition, at the time of heating and dissolving, it is preferable to add an antioxidant to prevent oxidation of polyethylene.
【００４０】次にこのポリエチレン組成物の加熱溶液を
ダイスから押し出して成形する。ダイスは、通常偏平な
口金形状をしたシートダイスが用いられるが、２重円筒
状の中空ダイス、インフレーションダイス等も用いるこ
とができる。シートダイスを用いた場合のダイスギャッ
プは通常0.1 〜５mmであり、押出し成形時には140 〜25
0 ℃に加熱される。この際押し出し速度は、通常20〜30
cm／分乃至２〜３ｍ／分である。Next, the heated solution of the polyethylene composition is extruded from a die and molded. As the die, a sheet die having a flat die shape is generally used, but a double cylindrical hollow die, an inflation die and the like can also be used. The die gap when a sheet die is used is usually 0.1 to 5 mm, and is 140 to 25 mm at the time of extrusion molding.
Heat to 0 ° C. At this time, the extrusion speed is usually 20-30
cm / min to 2-3 m / min.
【００４１】このようにしてダイスから押し出された溶
液は、冷却することによりゲル状物に成形される。冷却
は少なくともゲル化温度以下までは50℃/ 分以上の速度
で行うのが好ましい。冷却速度が遅いと結晶化度が上昇
し、延伸に適したゲル状物となりにくい。冷却方法とし
ては、冷風、冷却水、その他の冷却媒体に直接接触させ
る方法、冷媒で冷却したロールに接触させる方法等を用
いることができる。なおダイスから押し出された溶液
は、冷却前あるいは冷却中に、１〜10好ましくは１〜５
の引取比で引き取っても良い。引取比が10以上になると
ネックインが大きくなり、また延伸時に破断を起こしや
すくなり好ましくない。The solution thus extruded from the die is formed into a gel by cooling. Cooling is preferably performed at a rate of 50 ° C./min or more at least up to the gelation temperature. When the cooling rate is low, the crystallinity increases, and it is difficult to form a gel suitable for stretching. As a cooling method, a method of directly contacting with cold air, cooling water, or another cooling medium, a method of contacting with a roll cooled by a refrigerant, or the like can be used. Note that the solution extruded from the die may be 1 to 10, preferably 1 to 5, before or during cooling.
May be picked up at the pick-up ratio. When the take-up ratio is 10 or more, neck-in becomes large, and breakage tends to occur during stretching, which is not preferable.
【００４２】次にこのゲル状成形物を延伸する。延伸
は、ゲル状成形物を加熱し、通常のテンター法、ロール
法、インフレーション法、圧延法もしくはこれらの方法
の組合せによって所定の倍率で行う。２軸延伸が好まし
く、縦横同時延伸または逐次延伸のいずれでもよいが、
特に同時２軸延伸が好ましい。Next, this gel-like molded product is stretched. The stretching is performed at a predetermined magnification by heating the gel-like molded product and using a usual tenter method, a roll method, an inflation method, a rolling method or a combination of these methods. Biaxial stretching is preferred, and any of vertical and horizontal simultaneous stretching or sequential stretching may be used.
Particularly, simultaneous biaxial stretching is preferable.
【００４３】延伸温度は、ポリエチレン組成物の融点＋
10℃以下、好ましくは結晶分散温度から結晶融点未満の
範囲である。例えば、第一のポリエチレン組成物の場合
は90〜135 ℃で、より好ましくは、110 〜125 ℃の範囲
であり、第二のポリエチレン組成物の場合は90〜135 ℃
で、より好ましくは、110 〜125 ℃の範囲である。延伸
温度が融点＋10℃を超える場合は、樹脂の溶融により延
伸による分子鎖の配向ができない。また、延伸温度が結
晶分散温度未満では、樹脂の軟化が不十分で、延伸にお
いて破膜し易く、高倍率の延伸ができない。The stretching temperature is the melting point of the polyethylene composition +
It is 10 ° C. or less, preferably in the range from the crystal dispersion temperature to less than the crystal melting point. For example, in the range of 90-135 ° C for the first polyethylene composition, more preferably in the range of 110-125 ° C, and in the case of the second polyethylene composition 90-135 ° C.
And more preferably in the range of 110 to 125 ° C. When the stretching temperature exceeds the melting point + 10 ° C., the molecular chains cannot be oriented by stretching due to the melting of the resin. On the other hand, if the stretching temperature is lower than the crystal dispersion temperature, the resin is insufficiently softened, the film is easily broken in stretching, and high-magnification stretching cannot be performed.
【００４４】また、延伸倍率は原反の厚さによって異な
るが、１軸方向で少なくとも２倍以上、好ましくは３〜
20倍、面倍率で10倍以上、好ましくは20〜400 倍であ
る。面倍率が10倍未満では延伸が不十分で高弾性、高強
度の微多孔膜が得られない。一方、面倍率が400 倍を超
えると、延伸装置、延伸操作などの点で制約が生じる。The stretching ratio varies depending on the thickness of the raw material, but is at least twice, preferably from 3 to 1 in the uniaxial direction.
The magnification is 20 times or more, and the area magnification is 10 times or more, preferably 20 to 400 times. If the areal magnification is less than 10 times, stretching is insufficient and a highly elastic and high-strength microporous film cannot be obtained. On the other hand, when the area magnification exceeds 400 times, restrictions are imposed on a stretching apparatus, a stretching operation, and the like.
【００４５】得られた延伸成形物を溶剤で洗浄し、残留
する溶媒を除去する。洗浄溶剤としては、ペンタン、ヘ
キサン、ヘプタンなどの炭化水素、塩化メチレン、四塩
化炭素などの塩素化炭化水素、三フッ化エタンなどのフ
ッ化炭化水素、ジエチルエーテル、ジオキサンなどのエ
ーテル類などの易揮発性のものを用いることができる。
これらの溶剤はポリエチレン組成物の溶解に用いた溶媒
に応じて適宜選択し、単独もしくは混合して用いる。洗
浄方法は、溶剤に浸漬し抽出する方法、溶剤をシャワー
する方法、またはこれらの組合せによる方法などにより
行うことができる。The obtained stretch molded product is washed with a solvent to remove the remaining solvent. Examples of the cleaning solvent include hydrocarbons such as pentane, hexane, and heptane; chlorinated hydrocarbons such as methylene chloride and carbon tetrachloride; fluorinated hydrocarbons such as ethane trifluoride; and ethers such as diethyl ether and dioxane. Volatile ones can be used.
These solvents are appropriately selected according to the solvent used for dissolving the polyethylene composition, and used alone or as a mixture. The washing method can be performed by a method of immersing in a solvent for extraction, a method of showering the solvent, a method of a combination thereof, or the like.
【００４６】上述のような洗浄は、延伸成形物中の残留
溶媒が１重量％未満になるまで行う。その後洗浄溶剤を
乾燥するが、洗浄溶剤の乾燥方法は加熱乾燥、風乾など
の方法で行うことができる。乾燥した延伸成形物は、結
晶分散温度〜融点の温度範囲で熱固定することが望まし
い。The washing as described above is performed until the residual solvent in the stretch molded product becomes less than 1% by weight. Thereafter, the washing solvent is dried, and the washing solvent can be dried by a method such as heat drying or air drying. It is desirable that the dried stretch molded product is heat-set at a temperature in the range of the crystal dispersion temperature to the melting point.
【００４７】以上のようにして製造したポリエチレン微
多孔膜は、空孔率が35〜95％、平均貫通孔径が 0.001〜
１μｍ、引張破断強度が200kg/cm2 以上であり、透過性
遮断温度が135 ℃未満である。通常、高密度ポリエチレ
ンあるいは超高分子量ポリエチレンによる微多孔の透過
性遮断温度は135 〜145 ℃であることから、リチウム電
池等の電池用セパレータ等としての安全性の点で大幅に
向上したものと言える。また本発明のポリエチレン微多
孔膜の厚さは、用途に応じて適宜選択しうるが、一般に
0.1 〜50μｍであり、好ましくは５〜40μｍにすること
ができる。The microporous polyethylene membrane produced as described above has a porosity of 35 to 95% and an average through-pore diameter of 0.001 to 0.005.
1 μm, tensile strength at break is 200 kg / cm 2 or more, and permeability cutoff temperature is less than 135 ° C. Normally, the permeability blocking temperature of microporous material made of high-density polyethylene or ultra-high-molecular-weight polyethylene is 135 to 145 ° C, which can be said to be greatly improved in terms of safety as a separator for a battery such as a lithium battery. . Further, the thickness of the polyethylene microporous membrane of the present invention can be appropriately selected according to the application, but generally,
It is 0.1-50 μm, preferably 5-40 μm.
【００４８】なお、得られたポリエチレン微多孔膜は、
必要に応じてさらに、プラズマ照射、界面活性剤含浸、
表面グラフト等で親水化処理することができる。The resulting polyethylene microporous membrane was
If necessary, further plasma irradiation, surfactant impregnation,
Hydrophilic treatment can be performed by surface grafting or the like.
【００４９】[0049]
【実施例】以下に本発明の実施例を示す。なお、実施例
における試験方法はつぎの通りである。 (1) 分子量及び分子量分布：ウォーターズ（社）製のGP
C 装置を用い、カラムに東ソー（株）製GMH-6 、溶媒に
O-ジクロルベンゼンを使用し、温度135 ℃、流量1.0 ml
/ 分にて、ゲルパーミエーションクロマトグラフィー
（GPC)法により測定。 (2) 引張破断強度：ASTM D882 に準拠して測定。 (3) フィルムの厚さ：断面を走査型電子顕微鏡により測
定。 (4) 透気度：JIS P8117 に準拠して測定。 (5) 透水性：微多孔膜を平膜モジュールに組み込み、蒸
留水／エタノール混合液（50/50 容積比) で親水化処理
を行い、蒸留水で十分に洗浄した後、380 mmHgの水圧を
かけたときの濾液の透過量を測定して求めた。 (6) 平均貫通孔径：上記(5) で記載したモジュールを用
いて、380 mmHgの差圧下で0.05重量％のプルラン（昭和
電工（株）製) の水溶液を循環させたときに、濾液中に
含まれるプルランの濃度を示差屈折率測定から求め、次
式により計算した阻止率が50％になるプルランの分子量
の値から、後述するようなFlory の理論を利用して、孔
径を算出した。 プルランの阻止率＝｛１−（濾液中のプルラン濃度 /原
液中のプルラン濃度）｝×100 溶液状態にある鎖状高分子は球状の糸まり状で、その直
径d は、分子鎖の両末端の２乗平均距離〈γ2 〉に対し
て、近似的に 〔d/2 〕2 ＝〈γ2 〉・・・(1) の関係にあると考えて良い。高分子溶液における粘性と
分子鎖の広がりに関するFlory の理論によると、高分子
の種類に無関係に 〔η〕Ｍ＝2.1 ×1021〈γ2 〉3/2 ・・・(2) が成立するので、式(1) 及び(2) により、固有粘度
〔η〕の測定値と、阻止率が50％になる分子量Ｍとから
鎖状高分子の直径d を算出することができる。このｄを
ポリエチレン微多孔膜の平均孔径とした。 (7) 空孔率：水銀ポロシメータにより測定。 (8) 透過性遮断温度：微多孔膜を枠で固定し、２分間所
定温度下に放置し、透気度が104 sec/100cc を超えた温
度を測定した。 (9) 実効抵抗：プロピレンカーボネートと、1,2-ジメト
キシエタンの１：１混合溶媒に、 LiClO4 を１mol/リッ
トルになるように溶解した電解液を調製し、この電解液
と、ステンレス電極を用い、正負両電極間にセパレータ
(ポリエチレン微多孔膜) を設置してアルゴン雰囲気
中、25℃において測定した複合インピーダンスプロット
から求めた。Examples of the present invention will be described below. In addition, the test method in an Example is as follows. (1) Molecular weight and molecular weight distribution: GP manufactured by Waters Corporation
Using C apparatus, GMH-6 manufactured by Tosoh Corp.
Using O-dichlorobenzene, temperature 135 ° C, flow rate 1.0 ml
Per minute, measured by gel permeation chromatography (GPC). (2) Tensile breaking strength: measured according to ASTM D882. (3) Film thickness: The cross section was measured with a scanning electron microscope. (4) Air permeability: Measured according to JIS P8117. (5) Water permeability: After incorporating the microporous membrane into the flat membrane module, hydrophilizing with a mixed solution of distilled water / ethanol (50/50 volume ratio), washing thoroughly with distilled water, and increasing the water pressure to 380 mmHg. The permeation amount of the filtrate when applied was measured and determined. (6) Average through-hole diameter: When a 0.05% by weight aqueous solution of pullulan (manufactured by Showa Denko KK) is circulated under a differential pressure of 380 mmHg using the module described in (5) above, The concentration of the contained pullulan was determined from the measurement of the differential refractive index, and the pore size was calculated from the value of the molecular weight of the pullulan having a rejection of 50% calculated by the following equation, using Flory's theory as described later. Pullulan rejection = {1-(Pullulan concentration in filtrate / Pullulan concentration in stock solution)} x 100 The chain polymer in the form of a solution is in the form of a spherical thread, and its diameter d is the both ends of the molecular chain. It can be considered that there is an approximate relationship of [d / 2] 2 = <γ 2 > (1) with respect to the mean square distance <γ 2 >. According to Flory's theory of viscosity and molecular chain spread in a polymer solution, [η] M = 2.1 × 10 21 <γ 2 > 3/2 ... (2) holds regardless of the type of polymer. From formulas (1) and (2), the diameter d of the chain polymer can be calculated from the measured value of the intrinsic viscosity [η] and the molecular weight M at which the rejection becomes 50%. This d was defined as the average pore size of the polyethylene microporous membrane. (7) Porosity: Measured with a mercury porosimeter. (8) permeable blocking temperature to fix the microporous membrane in a frame, and placed under predetermined 2 minutes temperature, the air permeability was measured temperatures in excess of 10 4 sec / 100cc. (9) Effective resistance: An electrolytic solution was prepared by dissolving LiClO 4 in a 1: 1 mixed solvent of propylene carbonate and 1,2-dimethoxyethane so as to have a concentration of 1 mol / L. Used, separator between positive and negative electrodes
(Polyethylene microporous membrane) was installed and determined from a composite impedance plot measured at 25 ° C. in an argon atmosphere.
【００５０】実施例１ 重量平均分子量が２．０×１０６の超高分子量ポリエチ
レン（ＵＨＭＷＰＥ）２０重量％と、３．９×１０５の
高密度ポリエチレン（ＨＤＰＥ）６６．７重量％と、メ
ルトインデックス（ＭＩ、１９０℃、２．１６ｋｇ荷
重）２．０ｇ／１０分の低密度ポリエチレン（ＬＤＰ
Ｅ）１３．３重量％とを混合した原料樹脂であるポリエ
チレン組成物（融点１３２℃）１５重量部と、流動パラ
フィン（６４ｃｓｔ／４０℃）８５重量部とを混合し、
ポリエチレン組成物の溶液を調製した。次にこのポリエ
チレン組成物の溶液１００重量部に、２，５−ジ−ｔ−
ブチル−ｐ−クレゾール（「ＢＨＴ」、住友化学工業
（株）製）０．１２５重量部と、テトラキス〔メチレン
−３−（３，５−ジ−ｔ−ブチル−４−ヒドロキシルフ
ェニル）−プロピオネート〕メタン（「イルガノックス
１０１０」、チバガイギー製）０．２５重量部とを酸化
防止剤として加えた。この混合液を撹拌機付のオートク
レーブに充填し、２００℃で９０分間撹拌して均一な溶
液を得た。 Example 1 20% by weight of ultra high molecular weight polyethylene (UHMWPE) having a weight average molecular weight of 2.0 × 10 6 , 66.7% by weight of 3.9 × 10 5 high density polyethylene (HDPE), and melt Index (MI, 190 ° C, 2.16 kg load) 2.0 g / 10 min low density polyethylene (LDP
E) Polyether which is a raw material resin mixed with 13.3% by weight
Mixing 15 parts by weight of a styrene composition (melting point 132 ° C.) and 85 parts by weight of liquid paraffin (64 cst / 40 ° C.)
A solution of the polyethylene composition was prepared. Next, 100 parts by weight of the solution of the polyethylene composition was added to 2,5-di-t-
0.125 parts by weight of butyl-p-cresol (“BHT”, manufactured by Sumitomo Chemical Co., Ltd.) and tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) -propionate] 0.25 parts by weight of methane (“Irganox 1010”, manufactured by Ciba Geigy) was added as an antioxidant. This mixture was filled in an autoclave equipped with a stirrer, and stirred at 200 ° C. for 90 minutes to obtain a uniform solution.
【００５１】この溶液を直径45mmの押出機により、Ｔダ
イから押出し、冷却ロールで引取りながらゲル状シート
を成形した。This solution was extruded from a T-die by an extruder having a diameter of 45 mm, and was formed into a gel-like sheet while being taken up by a cooling roll.
【００５２】得られたシートを二軸延伸機にセットし
て、温度 115℃、延伸速度 0.5ｍ／分で５×５倍に同時
二軸延伸を行った。得られた延伸膜を塩化メチレンで洗
浄して残留する流動パラフィンを抽出除去した後、100
℃で30秒熱セットすることによってポリエチレン微多孔
膜を得た。The obtained sheet was set on a biaxial stretching machine, and simultaneously biaxially stretched 5 × 5 times at a temperature of 115 ° C. and a stretching speed of 0.5 m / min. After washing the obtained stretched membrane with methylene chloride to extract and remove the remaining liquid paraffin, 100
A microporous polyethylene membrane was obtained by heat setting at 30 ° C for 30 seconds.
【００５３】得られたポリエチレン微多孔膜の膜厚、引
張破断強度、空孔率、平均貫通孔径、透気度、透過性遮
断温度及び実効抵抗の測定を行った。ポリエチレン微多
孔膜の組成及び製造条件を第１表に、またポリエチレン
微多孔膜の物性を第２表に示す。The thickness, tensile strength at break, porosity, average through-hole diameter, air permeability, permeability cutoff temperature and effective resistance of the obtained microporous polyethylene membrane were measured. Table 1 shows the composition and production conditions of the microporous polyethylene membrane, and Table 2 shows the physical properties of the microporous polyethylene membrane.
【００５４】実施例２ 重量平均分子量が２．０×１０６の超高分子量ポリエチ
レン（ＵＨＭＷＰＥ）２０重量％と、３．９×１０５の
高密度ポリエチレン（ＨＤＰＥ）６６．７重量％と、メ
ルトインデックス（ＭＩ、１９０℃、２．１６ｋｇ荷
重）１．５ｇ／１０分の線状低密度ポリエチレン（ＬＬ
ＤＰＥ）１３．３重量％とを混合した原料樹脂であるポ
リエチレン組成物（融点１３２℃）を用いた以外は実施
例１と同様にしてポリエチレン微多孔膜を製造した。 Example 2 20% by weight of ultra high molecular weight polyethylene (UHMWPE) having a weight average molecular weight of 2.0 × 10 6 , 66.7% by weight of 3.9 × 10 5 high density polyethylene (HDPE), and a melt Index (MI, 190 ° C, 2.16 kg load) 1.5 g / 10 min linear low density polyethylene (LL
DPE) is a raw material resin mixed with 13.3% by weight.
A microporous polyethylene membrane was produced in the same manner as in Example 1 except that the ethylene composition (melting point: 132 ° C.) was used.
【００５５】得られたポリエチレン微多孔膜の膜厚、引
張破断強度、空孔率、平均貫通孔径、透気度、透過性遮
断温度及び実効抵抗の測定を行った。ポリエチレン微多
孔膜の組成及び製造条件を第１表に、またポリエチレン
微多孔膜の物性を第２表に示す。The thickness, tensile strength at break, porosity, average through-hole diameter, air permeability, permeability cutoff temperature and effective resistance of the obtained microporous polyethylene membrane were measured. Table 1 shows the composition and production conditions of the microporous polyethylene membrane, and Table 2 shows the physical properties of the microporous polyethylene membrane.
【００５６】実施例３ 重量平均分子量が２．０×１０６の超高分子量ポリエチ
レン（ＵＨＭＷＰＥ）２０重量％と、３．９×１０５の
高密度ポリエチレン（ＨＤＰＥ）７７重量％と、メルト
インデックス（ＭＩ、１９０℃、２．１６ｋｇ荷重）
２．０ｇ／１０分の低密度ポリエチレン（ＬＤＰＥ）３
重量％とを混合した原料樹脂であるポリエチレン組成物
（融点１３４゜Ｃ）を用いた以外は実施例１と同様にし
て、ポリエチレン微多孔膜を製造した。 Example 3 20% by weight of ultra high molecular weight polyethylene (UHMWPE) having a weight average molecular weight of 2.0 × 10 6 , 77% by weight of 3.9 × 10 5 high density polyethylene (HDPE), and a melt index ( MI, 190 ° C, 2.16 kg load)
2.0 g / 10 min low density polyethylene (LDPE) 3
Polyethylene composition as raw material resin mixed with
(Melting point: 134 ° C.) A microporous polyethylene membrane was produced in the same manner as in Example 1 except that the melting point was 134 ° C.
【００５７】得られたポリエチレン微多孔膜の膜厚、引
張破断強度、空孔率、平均貫通孔径、透気度、透過性遮
断温度及び実効抵抗の測定を行った。ポリエチレン微多
孔膜の組成及び製造条件を第１表に、またポリエチレン
微多孔膜の物性を第２表に示す。The thickness, tensile strength at break, porosity, average through-hole diameter, air permeability, permeability cutoff temperature and effective resistance of the obtained microporous polyethylene membrane were measured. Table 1 shows the composition and production conditions of the microporous polyethylene membrane, and Table 2 shows the physical properties of the microporous polyethylene membrane.
【００５８】実施例４ 重量平均分子量が２．０×１０６の超高分子量ポリエチ
レン（ＵＨＭＷＰＥ）２０重量％と、３．９×１０５の
高密度ポリエチレン（ＨＤＰＥ）７７重量％と、メルト
インデックス（ＭＩ、１９０℃、２．１６ｋｇ荷重）
１．５ｇ／１０分の線状低密度ポリエチレン（ＬＬＤＰ
Ｅ）３重量％とを混合した原料樹脂であるポリエチレン
組成物（融点１３４℃）を用いた以外は実施例１と同様
にして、ポリエチレン微多孔膜を製造した。 Example 4 20% by weight of ultra high molecular weight polyethylene (UHMWPE) having a weight average molecular weight of 2.0 × 10 6 , 77% by weight of 3.9 × 10 5 high density polyethylene (HDPE), and a melt index ( MI, 190 ° C, 2.16 kg load)
1.5 g / 10 min linear low density polyethylene (LLDP
E) Polyethylene as raw material resin mixed with 3% by weight
A microporous polyethylene membrane was produced in the same manner as in Example 1 except that the composition (melting point: 134 ° C.) was used.
【００５９】得られたポリエチレン微多孔膜の膜厚、引
張破断強度、空孔率、平均貫通孔径、透気度、透過性遮
断温度及び実効抵抗の測定を行った。ポリエチレン微多
孔膜の組成及び製造条件を第１表に、またポリエチレン
微多孔膜の物性を第２表に示す。The thickness, tensile strength at break, porosity, average through-hole diameter, air permeability, permeability blocking temperature and effective resistance of the obtained microporous polyethylene membrane were measured. Table 1 shows the composition and production conditions of the microporous polyethylene membrane, and Table 2 shows the physical properties of the microporous polyethylene membrane.
【００６０】比較例１ 重量平均分子量が 2.0×106 の超高分子量ポリエチレン
(UHMWPE)13重量％と、3.9 ×105 の高密度ポリエチレン
(HDPE)87重量％とを混合した原料樹脂15重量部と、流動
パラフィン（64cst/40℃）85重量部とを混合し、ポリエ
チレン組成物の溶液を調製した。次にこのポリエチレン
組成物の溶液 100重量部に、2,5-ジ- t-ブチル-p- クレ
ゾール（「ＢＨＴ」、住友化学工業（株）製） 0.125重
量部と、テトラキス〔メチレン-3-(3,5-ジ-t- ブチル-4
- ヒドロキシルフェニル)-プロピオネート〕メタン
（「イルガノックス1010」、チバガイギ−製）0.25重量
部とを酸化防止剤として加えた。この混合液を撹拌機付
のオートクレーブに充填し、 200℃で90分間撹拌して均
一な溶液を得た。 Comparative Example 1 Ultra high molecular weight polyethylene having a weight average molecular weight of 2.0 × 10 6
(UHMWPE) 13% by weight and 3.9 × 10 5 high density polyethylene
(HDPE) 15 parts by weight of a raw resin mixed with 87% by weight and 85 parts by weight of liquid paraffin (64 cst / 40 ° C.) were mixed to prepare a solution of a polyethylene composition. Next, 0.125 parts by weight of 2,5-di-t-butyl-p-cresol ("BHT", manufactured by Sumitomo Chemical Co., Ltd.) was added to 100 parts by weight of the solution of the polyethylene composition, and tetrakis [methylene-3- (3,5-di-t-butyl-4
-Hydroxylphenyl) -propionate] methane ("Irganox 1010", Ciba-Geigy) in an amount of 0.25 parts by weight as an antioxidant. This mixture was filled in an autoclave equipped with a stirrer, and stirred at 200 ° C. for 90 minutes to obtain a uniform solution.
【００６１】この溶液を直径45mmの押出機により、Ｔダ
イから押出し、冷却ロールで引取りながらゲル状シート
を成形した。This solution was extruded from a T-die by an extruder having a diameter of 45 mm, and a gel-like sheet was formed while being taken up by a cooling roll.
【００６２】得られたシートを二軸延伸機にセットし
て、温度 115℃、延伸速度 0.5ｍ／分で５×５倍に同時
二軸延伸を行った。得られた延伸膜を塩化メチレンで洗
浄して残留する流動パラフィンを抽出除去した後、115
℃で30秒熱セットすることによってポリエチレン微多孔
膜を得た。The obtained sheet was set on a biaxial stretching machine and simultaneously biaxially stretched 5 × 5 times at a temperature of 115 ° C. and a stretching speed of 0.5 m / min. After washing the obtained stretched membrane with methylene chloride to extract and remove the remaining liquid paraffin, 115
A microporous polyethylene membrane was obtained by heat setting at 30 ° C for 30 seconds.
【００６３】得られたポリエチレン微多孔膜の膜厚、引
張破断強度、空孔率、平均貫通孔径、透気度、透過性遮
断温度及び実効抵抗の測定を行った。ポリエチレン微多
孔膜の組成及び製造条件を第１表に、またポリエチレン
微多孔膜の物性を第２表に示す。The thickness, tensile strength at break, porosity, average through-hole diameter, air permeability, permeability cutoff temperature and effective resistance of the obtained microporous polyethylene membrane were measured. Table 1 shows the composition and production conditions of the microporous polyethylene membrane, and Table 2 shows the physical properties of the microporous polyethylene membrane.
【００６４】比較例２ 重量平均分子量が 2.0×106 の超高分子量ポリエチレン
(UHMWPE)10重量％と、3.9 ×105 の高密度ポリエチレン
(HDPE)55重量％と、メルトインデックス (MI、190 ℃、
2.16kg荷重) 2.0 ｇ/10 分の低密度ポリエチレン(LDPE)
35重量％とを混合した原料樹脂を用いた以外は実施例１
と同様にして、ポリエチレン微多孔膜を製造した。 Comparative Example 2 Ultra high molecular weight polyethylene having a weight average molecular weight of 2.0 × 10 6
(UHMWPE) 10% by weight and 3.9 × 10 5 high density polyethylene
(HDPE) 55% by weight and melt index (MI, 190 ° C,
2.16 kg load) 2.0 g / 10 min low density polyethylene (LDPE)
Example 1 except that a raw resin mixed with 35% by weight was used.
In the same manner as in the above, a microporous polyethylene membrane was produced.
【００６５】得られたポリエチレン微多孔膜の膜厚、引
張破断強度、空孔率、平均貫通孔径、透気度、透過性遮
断温度及び実効抵抗の測定を行った。ポリエチレン微多
孔膜の組成及び製造条件を第１表に、またポリエチレン
微多孔膜の物性を第２表に示す。The thickness, tensile strength at break, porosity, average through-hole diameter, air permeability, permeability cutoff temperature and effective resistance of the obtained microporous polyethylene membrane were measured. Table 1 shows the composition and production conditions of the microporous polyethylene membrane, and Table 2 shows the physical properties of the microporous polyethylene membrane.
【００６６】比較例３ 重量平均分子量が 2.0×106 の超高分子量ポリエチレン
(UHMWPE)10重量％と、3.9 ×105 の高密度ポリエチレン
(HDPE)55重量％と、メルトインデックス (MI、190 ℃、
2.16kg荷重) 1.5 ｇ/10 分の線状低密度ポリエチレン(L
LDPE) 35重量％とを混合した原料樹脂を用いた以外は実
施例１と同様にして、ポリエチレン微多孔膜を製造し
た。 Comparative Example 3 Ultra high molecular weight polyethylene having a weight average molecular weight of 2.0 × 10 6
(UHMWPE) 10% by weight and 3.9 × 10 5 high density polyethylene
(HDPE) 55% by weight and melt index (MI, 190 ° C,
2.16 kg load) 1.5 g / 10 min linear low density polyethylene (L
LDPE) A microporous polyethylene membrane was produced in the same manner as in Example 1 except that a raw material resin mixed with 35% by weight was used.
【００６７】得られたポリエチレン微多孔膜の膜厚、引
張破断強度、空孔率、平均貫通孔径、透気度、透過性遮
断温度及び実効抵抗の測定を行った。ポリエチレン微多
孔膜の組成及び製造条件を第１表に、またポリエチレン
微多孔膜の物性を第２表に示す。The thickness, tensile strength at break, porosity, average through-hole diameter, air permeability, permeability blocking temperature and effective resistance of the obtained microporous polyethylene membrane were measured. Table 1 shows the composition and production conditions of the microporous polyethylene membrane, and Table 2 shows the physical properties of the microporous polyethylene membrane.
【００６８】 第 １ 表組成 (重量％) 実施例１ 実施例２ 実施例３ 実施例４ ＵＨＭＷＰＥ 20 20 20 20 ＨＤＰＥ 66.7 66.7 77 77 ＬＤＰＥ 13.3 − ３ − ＬＬＤＰＥ − 13.3 − ３ 製造条件 延伸温度（℃） 115 115 115 115 熱セット温度（℃） 100 100 100 100 Table 1 Composition (% by weight) Example 1 Example 2 Example 3 Example 4 UHMWPE 20 20 20 20 HDPE 66.7 66.7 77 77 LDPE 13.3-3-LLDPE-13.3-3 Manufacturing conditions Stretching temperature (° C.) 115 115 115 115 Heat setting temperature (℃) 100 100 100 100
【００６９】 第 １ 表 (続 き)組成 (重量％) 比較例１ 比較例２ 比較例３ ＵＨＭＷＰＥ 13 10 10 ＨＤＰＥ 87 55 55 ＬＤＰＥ − 35 − ＬＬＤＰＥ − − 35製造条件 延伸温度（℃） 115 115 115 熱セット温度（℃） 115 100 100Table 1 (continued) Composition (% by weight) Comparative Example 1 Comparative Example 2 Comparative Example 3 UHMWPE 13 10 10 HDPE 87 55 55 LDPE-35-LLDPE--35 Manufacturing Conditions Stretching Temperature (° C.) 115 115 115 Heat setting temperature (℃) 115 100 100
【００７０】 第 ２ 表 特 性 実施例１ 実施例２ 実施例３ 実施例４ 膜厚(1) 25 25 25 25 空孔率(2) 50 60 55 50 平均貫通孔径(3) 0.025 0.025 0.03 0.03 引張破断強度(4) MD 800 800 880 920 TD 640 600 680 720 透気度(5) 952 612 780 580 透過性遮断温度(6) 115 120 120 125 実効抵抗(7) 2.21 2.15 2.18 2.12 [0070] Table 2 Characteristics Example 1 Example 2 Example 3 Example 4 thickness (1) 25 25 25 25 Porosity (2) 50 60 55 50 Average penetration pore diameter (3) 0.025 0.025 0.03 0.03 Tensile Breaking strength (4) MD 800 800 880 920 TD 640 600 680 720 Air permeability (5) 952 612 780 580 Permeability cut-off temperature (6) 115 120 120 125 Effective resistance (7) 2.21 2.15 2.18 2.12
【００７１】 [0071]
【００７２】注）＊：微多孔化していなかった。 (1)：単位はμｍ。 (2)：単位は％。 (3)：単位はμｍ。 (4)：単位は kg/cm2 で、長手方向（MD）と幅方向(TD)
について表示。 (5)：単位はsec/100cc 。 (6)：単位は℃。 (7)：単位はΩ・cm2 Note) *: Not microporous. (1): The unit is μm. (2): Unit is%. (3): The unit is μm. (4): The unit is kg / cm 2, the longitudinal direction (MD) and transverse direction (TD)
About. (5): The unit is sec / 100cc. (6): The unit is ° C. (7): The unit is Ω · cm 2
【００７３】実施例５ 重量平均分子量が２．０×１０６の超高分子量ポリエチ
レン（ＵＨＭＷＰＥ）５０重量％と、メルトインデック
ス（ＭＩ、１９０℃、２．１６ｋｇ荷重）２．０ｇ／１
０分の低密度ポリエチレン（ＬＤＰＥ）５０重量％とを
混合した原料樹脂であるポリエチレン組成物（融点１２
８℃）１５重量部と、流動パラフィン（６４ｃｓｔ／４
０℃）８５重量部とを混合し、ポリエチレン組成物の溶
液を調製した。次にこのポリエチレン組成物の溶液１０
０重量部に、２，５−ジ−ｔ−ブチル−ｐ−クレゾール
（「ＢＨＴ」、住友化学工業（株）製）０．１２５重量
部と、テトラキス〔メチレン−３−（３，５−ジ−ｔ−
ブチル−４−ヒドロキシルフェニル）−プロピオネー
ト〕メタン（「イルガノックス１０１０」、チバガイギ
ー製）０．２５重量部とを酸化防止剤として加えた。こ
の混合液を撹拌機付のオートクレーブに充填し、２００
℃で９０分間撹拌して均一な溶液を得た。 Example 5 50% by weight of ultra-high molecular weight polyethylene (UHMWPE) having a weight average molecular weight of 2.0 × 10 6 and a melt index (MI, 190 ° C., 2.16 kg load) of 2.0 g / 1
0% low-density polyethylene (LDPE) and 50% by weight of a polyethylene composition (melting point 12
8 ° C.) 15 parts by weight and liquid paraffin (64 cst / 4)
(0 ° C.) and 85 parts by weight to prepare a solution of the polyethylene composition. Next, a solution 10 of this polyethylene composition
0 parts by weight, 0.125 parts by weight of 2,5-di-t-butyl-p-cresol (“BHT”, manufactured by Sumitomo Chemical Co., Ltd.) and tetrakis [methylene-3- (3,5-di- -T-
Butyl-4-hydroxylphenyl) -propionate] methane (“Irganox 1010”, Ciba-Geigy) 0.25 parts by weight was added as an antioxidant. This mixture was filled in an autoclave equipped with a stirrer,
Stirring at 90 ° C. for 90 minutes gave a homogeneous solution.
【００７４】この溶液を直径45mmの押出機により、Ｔダ
イから押出し、冷却ロールで引取りながらゲル状シート
を成形した。This solution was extruded from a T-die using an extruder having a diameter of 45 mm, and was formed into a gel-like sheet while being taken up by a cooling roll.
【００７５】得られたシートを二軸延伸機にセットし
て、温度 117℃、延伸速度 0.5ｍ／分で５×５倍に同時
二軸延伸を行った。得られた延伸膜を塩化メチレンで洗
浄して残留する流動パラフィンを抽出除去した後、100
℃で30秒熱セットすることによってポリエチレン微多孔
膜を得た。The obtained sheet was set on a biaxial stretching machine and simultaneously biaxially stretched 5 × 5 times at a temperature of 117 ° C. and a stretching speed of 0.5 m / min. After washing the obtained stretched membrane with methylene chloride to extract and remove the remaining liquid paraffin, 100
A microporous polyethylene membrane was obtained by heat setting at 30 ° C for 30 seconds.
【００７６】得られたポリエチレン微多孔膜の膜厚、引
張破断強度、空孔率、平均貫通孔径、透気度、透過性遮
断温度及び実効抵抗の測定を行った。ポリエチレン微多
孔膜の組成及び製造条件を第３表に、またポリエチレン
微多孔膜の物性を第４表に示す。The thickness, tensile rupture strength, porosity, average through-hole diameter, air permeability, permeability cutoff temperature and effective resistance of the obtained polyethylene microporous membrane were measured. Table 3 shows the composition and production conditions of the microporous polyethylene membrane, and Table 4 shows the physical properties of the microporous polyethylene membrane.
【００７７】実施例６ 実施例５において、低密度ポリエチレン（ＬＤＰＥ）の
代わりに、メルトインデックス（ＭＩ、 １９０℃、
２．１６ｋｇ荷重）１．５ｇ／１０分の線状低密度ポリ
エチレン（ＬＬＤＰＥ）を混合した原料樹脂であるポリ
エチレン組成物（融点１２９℃）を用いた以外は実施例
５と同様にしてポリエチレン微多孔膜を製造した。ポリ
エチレン微多孔膜の組成及び製造条件を第３表に、また
ポリエチレン微多孔膜の物性を第４表に示す。 Example 6 In Example 5, the melt index (MI, 190 ° C.,
2.16 kg load) 1.5 g / 10 min linear low density polyethylene (LLDPE) mixed raw material resin
A microporous polyethylene membrane was produced in the same manner as in Example 5, except that the ethylene composition (melting point: 129 ° C.) was used. Table 3 shows the composition and production conditions of the microporous polyethylene membrane, and Table 4 shows the physical properties of the microporous polyethylene membrane.
【００７８】 第 ３ 表組成 (重量％) 実施例５ 実施例６ ＵＨＭＷＰＥ 50 50 ＬＤＰＥ 50 − ＬＬＤＰＥ − 50製造条件 延伸温度（℃） 117 117 熱セット温度（℃） 100 100Table 3 Composition (% by weight) Example 5 Example 6 UHMWPE 50 50 LDPE 50-LLDPE-50 Manufacturing conditions Stretching temperature (° C) 117 117 Heat setting temperature (° C) 100 100
【００７９】 [0079]
【００８０】注）＊：微多孔化していなかった。 (1)：単位はμｍ。 (2)：単位は％。 (3)：単位はμｍ。 (4)：単位は kg/cm2 で、長手方向（MD）と幅方向(TD)
について表示。 (5)：単位はsec/100cc 。 (6)：単位は℃。 (7)：単位はΩ・cm2 。Note) *: Not microporous. (1): The unit is μm. (2): Unit is%. (3): The unit is μm. (4): The unit is kg / cm 2, the longitudinal direction (MD) and transverse direction (TD)
About. (5): The unit is sec / 100cc. (6): The unit is ° C. (7): The unit is Ω · cm 2 .
【００８１】本実施例から明らかなように、実施例１乃
至６のポリエチレン微多孔膜は、引張破断強度の値が良
好であり、透気度が大きく、しかも透過性遮断温度が13
5 ℃未満であった。また実施例１乃至６のポリエチレン
微多孔膜は、実効抵抗の値も十分に小さいものであり、
電池用セパレータとして好適なものであることがわか
る。As is clear from this example, the microporous polyethylene membranes of Examples 1 to 6 have good values of the tensile strength at break, high air permeability, and a permeability cutoff temperature of 13%.
It was below 5 ° C. In addition, the microporous polyethylene membranes of Examples 1 to 6 have sufficiently small effective resistance values,
It turns out that it is suitable as a battery separator.
【００８２】[0082]
【発明の効果】以上詳述したように、本発明の第一のポ
リエチレン微多孔膜は、超高分子ポリエチレンと、高密
度ポリエチレンと、低密度ポリエチレンとを含有する組
成物からなるので、透過性及び機械的強度に優れるとと
もに、低温で透過性が遮断する。As described in detail above, the first microporous polyethylene membrane of the present invention is composed of a composition containing ultra-high-molecular-weight polyethylene, high-density polyethylene, and low-density polyethylene, and thus has a high permeability. And it has excellent mechanical strength and cuts off permeability at low temperatures.
【００８３】また、本発明の第二のポリエチレン微多孔
膜は、超高分子量ポリエチレンと、低密度ポリエチレン
とからなる組成物からなるので、透過性能及び機械的強
度に優れるとともに、低温で透過性能が遮断する。The second microporous polyethylene membrane of the present invention is composed of a composition comprising ultra-high molecular weight polyethylene and low-density polyethylene, so that it has excellent permeation performance and mechanical strength, and has low permeation performance at low temperatures. Cut off.
【００８４】このような本発明のポリエチレン微多孔膜
は、電池用セパレーター、電解コンデンサー用隔膜、光
シャッター、超精密濾過膜、限外濾過膜、各種フィルタ
ー、透湿防水衣料用多孔質膜等の各種用途に好適であ
り、特に電池用セパレーターに好適である。Such a polyethylene microporous membrane of the present invention can be used as a separator for a battery, a diaphragm for an electrolytic capacitor, an optical shutter, an ultrafine filtration membrane, an ultrafiltration membrane, various filters, a porous membrane for a moisture-permeable waterproof clothing, and the like. It is suitable for various uses, and particularly suitable for battery separators.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 恒吉 衛 埼玉県入間郡大井町西鶴ケ岡１−３−１ 東燃株式会社 総合研究所内 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Mamoru Tsuneyoshi 1-3-1 Nishitsurugaoka, Oimachi, Iruma-gun, Saitama
Claims (5)
子量ポリエチレン１〜69重量％と、高密度ポリエチレン
98〜１重量％と、低密度ポリエチレン１〜30重量％とを
含有し、前記超高分子量ポリエチレンと、高密度ポリエ
チレンとを含有する成分の重量平均分子量／数平均分子
量が10〜300 である組成物からなり、厚さが 0.1〜50μ
ｍ、空孔率が35〜95％、平均貫通孔径が 0.001〜１μ
ｍ、引張破断強度が200kg/cm2 以上であり、透過性遮断
温度が135 ℃未満であることを特徴とするポリエチレン
微多孔膜。An ultrahigh molecular weight polyethylene having a weight average molecular weight of 7 × 10 5 or more, 1 to 69% by weight, and a high density polyethylene.
A composition containing 98 to 1% by weight and 1 to 30% by weight of low-density polyethylene, wherein the component containing the ultrahigh-molecular-weight polyethylene and the high-density polyethylene has a weight-average molecular weight / number-average molecular weight of 10 to 300. Object, thickness 0.1 ~ 50μ
m, porosity is 35 ~ 95%, average through hole diameter is 0.001 ~ 1μ
m, a microporous polyethylene membrane having a tensile strength at break of 200 kg / cm 2 or more and a permeability cut-off temperature of less than 135 ° C.
子量ポリエチレン30〜90重量％と、低密度ポリエチレン
70〜10重量％とを含有する組成物からなり、厚さが 0.1
〜50μｍ、空孔率が35〜95％、平均貫通孔径が 0.001〜
１μｍ、引張破断強度が200kg/cm2 以上であり、透過性
遮断温度が135 ℃未満であることを特徴とするポリエチ
レン微多孔膜。2. An ultrahigh molecular weight polyethylene having a weight average molecular weight of 7 × 10 5 or more, 30 to 90% by weight, and a low density polyethylene.
70 to 10% by weight.
~ 50μm, porosity 35 ~ 95%, average through hole diameter 0.001 ~
A microporous polyethylene membrane having a tensile strength of 1 μm, a tensile strength at break of 200 kg / cm 2 or more, and a permeability cutoff temperature of less than 135 ° C.
子量ポリエチレン１〜69重量％と、高密度ポリエチレン
98〜１重量％と、低密度ポリエチレン１〜30重量％とを
含有し、前記超高分子量ポリエチレンと、高密度ポリエ
チレンとを含有する成分の重量平均分子量／数平均分子
量が10〜300 である組成物10〜50重量％と、溶媒50〜90
重量％とからなる溶液を調製し、前記溶液をダイより押
出し、冷却してゲル状組成物を形成し、前記ゲル状組成
物を前記ポリエチレン組成物の融点＋10℃以下の温度で
延伸し、しかる後残存溶媒を除去することを特徴とする
ポリエチレン微多孔膜の製造方法。3. A high-density polyethylene comprising 1 to 69% by weight of an ultrahigh molecular weight polyethylene having a weight average molecular weight of 7 × 10 5 or more.
A composition containing 98 to 1% by weight and 1 to 30% by weight of low-density polyethylene, wherein the component containing the ultrahigh-molecular-weight polyethylene and the high-density polyethylene has a weight-average molecular weight / number-average molecular weight of 10 to 300. 10 to 50% by weight, and solvent 50 to 90
% By weight, extruding the solution from a die, cooling to form a gel composition, and stretching the gel composition at a temperature equal to or lower than the melting point of the polyethylene composition + 10 ° C. A method for producing a microporous polyethylene membrane, comprising removing a residual solvent.
子量ポリエチレン30〜90重量％と、低密度ポリエチレン
70〜10重量％とを含有し、前記超高分子量ポリエチレン
と、高密度ポリエチレンとからなる組成物10〜50重量％
と、溶媒50〜90重量％とからなる溶液を調製し、前記溶
液をダイより押出し、冷却してゲル状組成物を形成し、
前記ゲル状組成物を前記ポリエチレン組成物の融点＋10
℃以下の温度で延伸し、しかる後残存溶媒を除去するこ
とを特徴とするポリエチレン微多孔膜の製造方法。4. An ultrahigh molecular weight polyethylene having a weight average molecular weight of 7 × 10 5 or more, 30 to 90% by weight, a low density polyethylene
70 to 10% by weight, the composition comprising the ultrahigh molecular weight polyethylene and the high density polyethylene 10 to 50% by weight
And a solution comprising 50 to 90% by weight of a solvent is prepared, the solution is extruded from a die, and cooled to form a gel composition,
The gel composition was melted at the melting point of the polyethylene composition +10.
A method for producing a microporous polyethylene membrane, comprising stretching at a temperature of not more than ° C and then removing the residual solvent.
多孔膜からなることを特徴とする電池用セパレータ。5. A battery separator comprising the microporous polyethylene membrane according to claim 1 or 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20474991A JP2657434B2 (en) | 1991-07-19 | 1991-07-19 | Polyethylene microporous membrane, method for producing the same, and battery separator using the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20474991A JP2657434B2 (en) | 1991-07-19 | 1991-07-19 | Polyethylene microporous membrane, method for producing the same, and battery separator using the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0525305A JPH0525305A (en) | 1993-02-02 |
| JP2657434B2 true JP2657434B2 (en) | 1997-09-24 |
Family
ID=16495699
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20474991A Expired - Fee Related JP2657434B2 (en) | 1991-07-19 | 1991-07-19 | Polyethylene microporous membrane, method for producing the same, and battery separator using the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2657434B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20180067421A (en) | 2016-12-12 | 2018-06-20 | 아사히 가세이 가부시키가이샤 | Polyethylene powder |
| CN110088181A (en) * | 2017-03-08 | 2019-08-02 | 东丽株式会社 | Polyolefin micro porous polyolefin membrane |
Families Citing this family (38)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3195120B2 (en) * | 1993-05-17 | 2001-08-06 | 三井化学株式会社 | Non-aqueous electrolyte battery separator |
| JP3455285B2 (en) * | 1994-05-16 | 2003-10-14 | 三井化学株式会社 | Porous biaxially oriented film comprising high molecular weight ethylene / α-olefin copolymer and use thereof |
| JP3746848B2 (en) * | 1995-07-18 | 2006-02-15 | 三井化学株式会社 | High molecular weight polyolefin microporous film and method for producing the same |
| AU1040897A (en) | 1995-12-05 | 1997-06-27 | Asahi Kasei Kogyo Kabushiki Kaisha | Microporous polyethylene membranes having low fusing temperatures |
| JP3948762B2 (en) * | 1996-02-21 | 2007-07-25 | 旭化成ケミカルズ株式会社 | Zinc bromine secondary battery separator |
| JP3682120B2 (en) * | 1996-06-04 | 2005-08-10 | 東燃化学株式会社 | Composite membrane for battery separator and battery separator |
| JP4008516B2 (en) * | 1996-08-02 | 2007-11-14 | 東燃化学株式会社 | Polyolefin porous membrane, method for producing the same, and battery separator using the same |
| JP3996226B2 (en) * | 1996-08-02 | 2007-10-24 | 東燃化学株式会社 | Nonaqueous battery separator and nonaqueous battery using the same |
| US5786396A (en) * | 1996-08-21 | 1998-07-28 | Tonen Chemical Corporation | Method of producing microporous polyolefin membrane |
| JPH1064501A (en) * | 1996-08-22 | 1998-03-06 | Matsushita Electric Ind Co Ltd | Nonaqueous electrolyte secondary battery |
| US5948557A (en) * | 1996-10-18 | 1999-09-07 | Ppg Industries, Inc. | Very thin microporous material |
| JPH10125299A (en) * | 1996-10-25 | 1998-05-15 | Matsushita Electric Ind Co Ltd | Nonaqueous electrolyte battery |
| JP3354430B2 (en) * | 1997-04-10 | 2002-12-09 | 三洋電機株式会社 | Solid electrolyte battery and method of manufacturing the same |
| JPH11300180A (en) * | 1998-02-20 | 1999-11-02 | Mitsubishi Chemical Corp | Porous resin membrane |
| JPH11283603A (en) | 1998-03-30 | 1999-10-15 | Noritake Co Ltd | Separator for battery and its manufacture |
| DE69915131T2 (en) * | 1998-10-01 | 2004-12-30 | Tonen Chemical Corp. | Microporous polyolefin membrane and method of making the same |
| WO2000020493A1 (en) * | 1998-10-01 | 2000-04-13 | Tonen Chemical Corporation | Microporous polyolefin film and process for producing the same |
| JP4170490B2 (en) * | 1999-01-05 | 2008-10-22 | 日東電工株式会社 | Microporous membrane |
| JP2000248088A (en) * | 1999-03-03 | 2000-09-12 | Tonen Chem Corp | Polyolefin microporous membrane and its production |
| JP4677663B2 (en) * | 2000-10-26 | 2011-04-27 | 東レ東燃機能膜合同会社 | Polyolefin microporous membrane |
| AU2003257544A1 (en) | 2002-08-28 | 2004-03-19 | Asahi Kasei Chemicals Corporations | Polyolefin microporous membrane and method of evaluating the same |
| US7445735B2 (en) | 2004-12-07 | 2008-11-04 | Daramic Llc | Method of making microporous material |
| JP4384630B2 (en) | 2004-12-23 | 2009-12-16 | トーレ・サエハン・インコーポレーテッド | Polyethylene microporous membrane for secondary battery separator and method for producing the same |
| WO2007034856A1 (en) | 2005-09-22 | 2007-03-29 | Mitsubishi Plastics, Inc. | Process for producing porous laminate and porous laminate |
| JP4546910B2 (en) | 2005-09-22 | 2010-09-22 | 三菱樹脂株式会社 | Method for producing porous laminate and porous laminate |
| JP4369921B2 (en) * | 2005-12-27 | 2009-11-25 | ダブル・スコープ 株式会社 | Microporous polyolefin diaphragm for secondary battery and method for producing the same |
| US8288038B2 (en) | 2006-05-22 | 2012-10-16 | Panasonic Corporation | Separator and non-aqueous electrolyte secondary battery |
| JP5426551B2 (en) | 2007-08-21 | 2014-02-26 | エー１２３ システムズ， インコーポレイテッド | Electrochemical cell separator and method for producing the same |
| US20120040232A1 (en) | 2009-03-30 | 2012-02-16 | Toray Tonen Specialty Separator Godo Kaisha | Microporous membranes and methods for making and using such membranes |
| CN103261294B (en) | 2010-12-22 | 2014-06-25 | 东丽电池隔膜株式会社 | Microporous film, manufacturing method for said film, and use for said film as battery separator film |
| US9896353B2 (en) | 2011-11-04 | 2018-02-20 | Ppg Industries Ohio, Inc. | Hydrocarbon waste stream purification processes using microporous materials having filtration and adsorption properties |
| US9546326B2 (en) | 2011-11-04 | 2017-01-17 | Ppg Industries Ohio, Inc. | Fluid emulsion purification processes using microporous materials having filtration and adsorption properties |
| US20130228529A1 (en) * | 2011-11-04 | 2013-09-05 | Ppg Industries Ohio, Inc. | Microporous material having filtration and adsorption properties and their use in fluid purification processes |
| US20130228519A1 (en) * | 2011-11-04 | 2013-09-05 | Ppg Industries Ohio, Inc. | Microporous material having filtration and adsorption properties and their use in fluid purification processes |
| CN107452919B (en) * | 2016-06-01 | 2020-08-28 | 上海恩捷新材料科技有限公司 | High-wettability isolating membrane and preparation method and application thereof |
| JP6858618B2 (en) * | 2017-03-30 | 2021-04-14 | 帝人株式会社 | Base material for liquid filter |
| CN111491719B (en) * | 2017-12-18 | 2022-11-29 | 香港科技大学 | Synthesis method of flexible multifunctional high-porosity ultrathin polyethylene film |
| CN116259924B (en) * | 2023-03-17 | 2024-01-02 | 江苏北星新材料科技有限公司 | Low-closed-pore-temperature diaphragm and preparation method thereof |
-
1991
- 1991-07-19 JP JP20474991A patent/JP2657434B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20180067421A (en) | 2016-12-12 | 2018-06-20 | 아사히 가세이 가부시키가이샤 | Polyethylene powder |
| CN110088181A (en) * | 2017-03-08 | 2019-08-02 | 东丽株式会社 | Polyolefin micro porous polyolefin membrane |
| CN110088181B (en) * | 2017-03-08 | 2022-04-15 | 东丽株式会社 | Polyolefin microporous membrane |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0525305A (en) | 1993-02-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2657434B2 (en) | Polyethylene microporous membrane, method for producing the same, and battery separator using the same | |
| JP3347854B2 (en) | Polyolefin microporous membrane, method for producing the same, battery separator and filter using the same | |
| JP2657430B2 (en) | Polyolefin microporous membrane and method for producing the same | |
| EP0355214B1 (en) | Process for producing microporous ultra-high molecular weight polyolefin membrane | |
| JP3347835B2 (en) | Method for producing microporous polyolefin membrane | |
| JPH06104736B2 (en) | Polyolefin microporous membrane | |
| US20090098341A1 (en) | Microporous polyolefin membrane and method for producing the same | |
| JP4234398B2 (en) | Microporous membrane, production method and use thereof | |
| JPH0987413A (en) | Production of finely porous membrane of polyolefin | |
| JP4234392B2 (en) | Microporous membrane, production method and use thereof | |
| JP3549290B2 (en) | Polyolefin microporous membrane and method for producing the same | |
| JPH05222236A (en) | Production of polyolefinic microporous film | |
| JP2000248093A (en) | Microporous polyolefin membrane and its production | |
| JPH07228718A (en) | Microporous polyolefin film | |
| JP3682120B2 (en) | Composite membrane for battery separator and battery separator | |
| JPH0812799A (en) | Polyolefin finely porous film and its manufacture | |
| JP3072163B2 (en) | Polyolefin microporous membrane, method for producing the same, and battery separator using the same | |
| JP3009495B2 (en) | Polyolefin microporous membrane and method for producing the same | |
| JPH09169867A (en) | Microporous film and its production | |
| JPH05222237A (en) | Production of polyolefinic microporous film | |
| JP2657431B2 (en) | Polyolefin microporous membrane and method for producing the same | |
| JPH093228A (en) | Production of polyolefin finely porous membrane | |
| JP3250894B2 (en) | Method for producing microporous polyolefin membrane | |
| JPH1192587A (en) | Preparation of polyolefin microporous film | |
| JP3967421B2 (en) | Method for producing polyolefin microporous membrane |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 11 Free format text: PAYMENT UNTIL: 20080606 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090606 Year of fee payment: 12 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100606 Year of fee payment: 13 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 13 Free format text: PAYMENT UNTIL: 20100606 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110606 Year of fee payment: 14 |
|
| S111 | Request for change of ownership or part of ownership |
Free format text: JAPANESE INTERMEDIATE CODE: R313113 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110606 Year of fee payment: 14 |
|
| R360 | Written notification for declining of transfer of rights |
Free format text: JAPANESE INTERMEDIATE CODE: R360 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 14 Free format text: PAYMENT UNTIL: 20110606 |
|
| R370 | Written measure of declining of transfer procedure |
Free format text: JAPANESE INTERMEDIATE CODE: R370 |
|
| LAPS | Cancellation because of no payment of annual fees | ||
| S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
| S111 | Request for change of ownership or part of ownership |
Free format text: JAPANESE INTERMEDIATE CODE: R313113 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| R360 | Written notification for declining of transfer of rights |
Free format text: JAPANESE INTERMEDIATE CODE: R360 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |