JP3681575B2 - Porous plastic filter - Google Patents
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- JP3681575B2 JP3681575B2 JP14419599A JP14419599A JP3681575B2 JP 3681575 B2 JP3681575 B2 JP 3681575B2 JP 14419599 A JP14419599 A JP 14419599A JP 14419599 A JP14419599 A JP 14419599A JP 3681575 B2 JP3681575 B2 JP 3681575B2
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Description
【０００１】
【発明の属する技術分野】
本発明は、液体や気体等の流体中に含まれる微粒子を分離・濾過するための多孔質プラスチックフィルタに関する
【０００２】
【従来の技術】
従来から、液体や気体等の流体中に含まれる微粒子を分離・濾過するために、多孔質プラスチックフィルタを使用することは多数知られている。
その中でも超高分子量ポリエチレン粒子を焼結成形して得られる多孔質プラスチックフィルタは、（１）自立性があるためリテーナが不要であり、（２）布製フィルタのような毛羽立ちが無いのでコンタミネーションを起こさない、等の理由から粉体回収用のフィルタや防塵用のフィルタとして広く用いられている。
【０００３】
一般的に製品回収用のフィルタや除塵用のフィルタでは、フィルタ面で捕集された粉体や塵をそのまま放置しておくと、圧力損失が大きくなるため、粉体等の処理量の低下を招くことになる。このため、定期的にパルスエアで逆洗を行い、捕集された粉体を払い落としている。
このパルスエアは通常４〜６ｋｇ／ｃｍ2程度の高圧エアを用いる為、フィルタはその圧力に耐えるだけの強度を有している必要があり、また数年間という長い期間使用する場合、長期の耐久性も要求される。
【０００４】
【発明が解決しようとする課題】
しかしながら、実際にはフィルタ強度が十分でない為、使用開始後数ヶ月で逆洗によって破損するようなフィルタもあり、長期間の使用に耐えるような十分な強度を有するフィルタが求められていた。
【０００５】
【課題を解決する手段】
本発明は鋭意検討の結果、特定の溶融粘弾性特性を持っているポリエチレン粒子を用いて多孔質プラスチックフィルタを焼結成形すれば上記の課題を解決できることを見出したものである。
その要旨は、（１）熱可塑性プラスチック材料の粒子を焼結成形して得られる多孔質プラスチックフィルタであって、動的粘弾性測定により周波数１Ｈｚで測定した貯蔵弾性率（Ｇ´）が、１５０〜２５０℃の温度範囲で１．０×１０6〜２．０×１０7ｄｙｎ／ｃｍ2の範囲内にあるポリエチレン粒子を少なくとも含んでいることを特徴とする多孔質プラスチックフィルタである。
また、（２）上記に規定したポリエチレン粒子を、全体に対して１０ｗｔ％以上含有していることを特徴とする（１）記載の多孔質プラスチックフィルタである。
【０００６】
【発明の実施の形態】
本発明の多孔質プラスチックフィルタを構成する熱可塑性プラスチック材料としては、動的粘弾性測定により周波数１Ｈｚで測定した貯蔵弾性率（Ｇ´）が１５０〜２５０℃の温度範囲で１．０×１０6〜２．０×１０7ｄｙｎ／ｃｍ2の範囲内にあるポリエチレン粒子を少なくとも含んでいる必要がある。
【０００７】
動的粘弾性測定により周波数１Ｈｚで測定した貯蔵弾性率（Ｇ´）が、１５０〜２５０℃の温度範囲で１．０×１０6〜２．０×１０7ｄｙｎ／ｃｍ2の範囲内にあるポリエチレン粒子は、焼結成形した際の粒子間の融着強度が十分で、かつ粒子間の空隙は閉塞されないので、本発明の多孔質プラスチックフィルタ材料として好適に使用できる。
【０００８】
しかし、上記に規定した貯蔵弾性率（Ｇ´）が２．０×１０7ｄｙｎ／ｃｍ2以上のポリエチレン粒子を単独で焼結成形を行うと粒子同士の融着強度が小さく、強度のある多孔質プラスチックフィルタは得られないので、本発明の多孔質プラスチックフィルタ材料には適さない。
一方、当該貯蔵弾性率（Ｇ´）が１．０×１０6ｄｙｎ／ｃｍ2以下のポリエチレン粒子を単独で焼結成形を行うと粒子同士の融着強度は強固なものとなるが、空隙の閉塞が起こりやすく、その結果、圧力損失が大きくなりフィルタの性能上好ましくないので、同様に本発明の多孔質プラスチックフィルタ材料には適さない。
【０００９】
当該貯蔵弾性率が１．０×１０6〜２．０×１０7ｄｙｎ／ｃｍ2の範囲内にあるポリエチレン粒子を、当該貯蔵弾性率（Ｇ´）が２．０×１０7ｄｙｎ／ｃｍ2以上のポリエチレン粒子とブレンドして用いても良く、その際の当該貯蔵弾性率（Ｇ´）が１．０×１０6〜２．０×１０7ｄｙｎ／ｃｍ2の範囲内にあるポリエチレン粒子の割合は１０ｗｔ％以上が好ましく、さらに好ましくは２０ｗｔ％以上である。
当該貯蔵弾性率（Ｇ´）が１．０×１０6〜２．０×１０7ｄｙｎ／ｃｍ2の範囲内にあるポリエチレン粒子の含有量合が１０ｗｔ％以下ではブレンドによる効果が少なく、期待するほどの強度向上は望めない。
【００１０】
尚、本発明に使用する熱可塑性プラスチック材料の形態は、粉末状のものが好ましく、その平均粒径は５０〜７００μｍの範囲のものであれば良く、好ましくは６０〜５００μｍのものが好結果をもたらす。
平均粒径が５０μｍ以下では、濾過精度は向上するが粉体の通過時に圧力損失が大きくなり好ましくない。また、平均粒径が７００μｍの以上では、満足する濾過精度が得られず好ましくない。
【００１１】
また、本発明の多孔質フィルタの焼結成型方法は、特に制限はなく，通常は、いわゆる型内焼結法による。
すなわち、本発明の多孔質フィルタ成型方法は、筒状等の内表面形状を有する外金型と、当該外金型の内部に挿入した同様の外表面形状を有する内金型とからなる成形金型を用い、外型内表面と内型外表面の間隙部に形成されるキャビティ内に、熱可塑性プラスチックを充填した後、成形金型共々これを加熱する静的成型法が好適に採用できる。
場合によっては、シリンダ内にピストンを内蔵したラム式押出機を用いて行うラム押出法、シリンダ内にスクリュを内蔵した押出成形機を用いて行う押出成型法によっても連続的にプラスチックフィルタが成形できる。
【００１２】
【実施例】
以下、本発明の実施例を比較例と対比し具体的に説明する。
尚、焼結成形に用いる粒子及び多孔質プラスチックフィルタの評価は以下の様な方法で行った。
【００１３】
貯蔵弾性率の測定
２００℃×３０ｍｉｎ×３０ｋｇ／ｃｍ2のプレス成形条件にて作製したシートを４５ｍｍ×１２ｍｍ（厚み２ｍｍ）の短冊状に切り出し、動的粘弾性測定法により、昇温速度：２℃／ｍｉｎ、周波数：１Ｈｚ、窒素雰囲気中で３０〜２５０℃の貯蔵弾性率（Ｇ´）を測定した。
【００１４】
フィルタの引張強度
ＪＩＳ Ｋ−６２５１記載のダンベル状３号形試験片をフィルタより採取し、室温（２３℃）で引張速度：５ｍｍ／ｍｉｎにて測定した数値。
【００１５】
フィルタの気孔率
フィルタの見掛け密度を下記▲１▼式により求め、下記▲２▼式によってフィルタの気孔率を算出した。
○見掛け密度（ρ1）（ｇ／ｃｍ3）＝Ｗ／Ｖ‥‥‥▲１▼
ただし、Ｗ：プラスチックフィルタの質量（ｇ）、Ｖ：プラスチックフィルタの体積（ｃｍ3）。
○気孔率（％）＝｛（ρ0−ρ1）／ρ0｝×１００‥‥‥▲２▼
ただし、ρ0：プラスチックフィルタを構成する熱可塑性プラスチック材料の真密度（ｇ／ｃｍ3）。
【００１６】
フィルタの圧力損失
中空円筒状の多孔質プラスチックフィルタを、その中空円筒状の一方の開口にマノメータを装着し、他方の開口部に真空ポンプを装着し、当該真空ポンプで、フィルタの外表面積１ｍ2当たり所定流量（１ｍ3／ｍｉｎ、温度：２３℃、圧力１気圧）の空気になるように吸引し、その時の圧力差を測定し、圧力損失（ｍｍＡｑ）とした。
【００１７】
フィルタの逆洗耐久性評価
フィルタを集塵機内にセットし、圧力：６ｋｇ／ｃｍ2のエアをパルス的にフィルタの内部に供給し、逆洗回数：１００万回（約６年間の使用に相当）の耐久性試験を行い、目視によりフィルタの亀裂・破損の有無を確認した。判定は亀裂・破損がなければ「亀裂・破損無し」とし、亀裂・破損が発生した場合、その時の逆洗回数を記録した。
【００１８】
実施例１
１５０〜２５０℃の温度範囲での貯蔵弾性率（Ｇ´）が５．６７×１０6〜６．２２×１０6ｄｙｎ／ｃｍ2、平均粒径が１３０μｍのポリエチレン粒子を使用し、フィルタ厚みが３ｍｍになるような筒状金型内に振動充填し、２００℃の温度で３０ｍｉｎ加熱して焼結成形し、内径：５０ｍｍの円筒状多孔質プラスチックフィルタを得た。
このプラスチックフィルタの引張強度、圧力損失、気孔率及び逆洗耐久性の評価を表１に示す。
【００１９】
実施例２
１５０〜２５０℃の温度範囲での貯蔵弾性率（Ｇ´）が５．６７×１０6〜６．２２×１０6ｄｙｎ／ｃｍ2、平均粒径が１３０μｍのポリエチレン粒子と、１５０〜２５０℃の温度範囲での貯蔵弾性率（Ｇ´）が２．６３×１０7〜２．８２×１０7ｄｙｎ／ｃｍ2、平均粒径が６５μｍのポリエチレン粒子とを使用し、その混合割合３０／７０ｗｔ％に混合した後、フィルタ厚みが３ｍｍになるような筒状金型内に振動充填し、２００℃の温度で３０ｍｉｎ加熱して焼結成形し、内径：５０ｍｍの円筒状多孔質プラスチックフィルタを得た。
このプラスチックフィルタの引張強度、圧力損失、気孔率及び逆洗耐久性の評価を表１に示す。
【００２０】
比較例１
１５０〜２５０℃の温度範囲での貯蔵弾性率（Ｇ´）が２．６３×１０7〜２．８２×１０7ｄｙｎ／ｃｍ2、平均粒径が６５μｍのポリエチレン粒子を使用し、フィルタ厚みが３ｍｍになるような筒状金型内に振動充填し、２００℃の温度で３０ｍｉｎ加熱して焼結成形し、内径：５０ｍｍの円筒状多孔質プラスチックフィルタを得た。
このプラスチックフィルタの引張強度、圧力損失、気孔率及び逆洗耐久性の評価を表１に示す。
【００２１】
比較例２
１５０〜２５０℃の温度範囲での貯蔵弾性率（Ｇ´）が５．６７×１０6〜６．２２×１０6ｄｙｎ／ｃｍ2、平均粒径が１３０μｍのポリエチレン粒子と、１５０〜２５０℃の温度範囲での貯蔵弾性率（Ｇ´）が２．６３×１０7〜２．８２×１０7ｄｙｎ／ｃｍ2、平均粒径が６５μｍのポリエチレン粒子とを使用し、その混合割合５／９５ｗｔ％に混合した後、フィルタ厚みが３ｍｍになるような筒状金型内に振動充填し、２００℃の温度で３０ｍｉｎ加熱して焼結成形し、内径：５０ｍｍの円筒状多孔質プラスチックフィルタを得た。
このプラスチックフィルタの引張強度、圧力損失、気孔率及び逆洗耐久性の評価を表１に示す。
【００２２】
【表１】
表１に示す如く、実施例１、２においては逆洗耐久性も問題なく、また圧力損失の値も実用上問題の無いレベルであった。
一方、比較例１，２では圧力損失は低いが約４０〜４５万回の逆洗でフィルタが破損し長期耐久性に問題があった。
【００２４】
【発明の効果】
以上説明したように、本発明による多孔質プラスチックフィルタは逆洗耐久性に問題が無く、また圧力損失の値においても実用上問題の無いレベルの多孔質プラスチックフィルタであった。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a porous plastic filter for separating and filtering fine particles contained in a fluid such as liquid or gas.
[Prior art]
Conventionally, many use of a porous plastic filter is known for separating and filtering fine particles contained in a fluid such as liquid or gas.
Among them, porous plastic filters obtained by sintering and molding ultra-high molecular weight polyethylene particles are (1) self-supporting, so no retainer is required, and (2) there is no fuzz like cloth filters, so contamination It is widely used as a powder recovery filter or a dustproof filter because it does not occur.
[0003]
Generally, in the filter for product recovery and the filter for dust removal, if the powder or dust collected on the filter surface is left as it is, the pressure loss increases, so the processing amount of the powder etc. decreases. Will be invited. For this reason, backwashing is periodically performed with pulsed air, and the collected powder is removed.
Since this pulse air normally uses high-pressure air of about 4-6 kg / cm 2 , the filter must be strong enough to withstand the pressure, and if it is used for a long period of several years, it has long-term durability. Is also required.
[0004]
[Problems to be solved by the invention]
However, since the filter strength is actually insufficient, some filters may be damaged by backwashing within a few months after the start of use, and a filter having sufficient strength to withstand long-term use has been demanded.
[0005]
[Means for solving the problems]
As a result of intensive studies, the present invention has found that the above-mentioned problems can be solved by sintering and molding a porous plastic filter using polyethylene particles having specific melt viscoelastic properties.
The summary is (1) a porous plastic filter obtained by sintering and molding particles of a thermoplastic material, and has a storage elastic modulus (G ′) measured at a frequency of 1 Hz by dynamic viscoelasticity measurement of 150. A porous plastic filter comprising at least polyethylene particles in a range of 1.0 × 10 6 to 2.0 × 10 7 dyn / cm 2 in a temperature range of −250 ° C.
(2) The porous plastic filter according to (1), wherein the polyethylene particles defined above are contained in an amount of 10 wt% or more based on the whole.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
As a thermoplastic material constituting the porous plastic filter of the present invention, a storage elastic modulus (G ′) measured at a frequency of 1 Hz by dynamic viscoelasticity measurement is 1.0 × 10 6 in a temperature range of 150 to 250 ° C. It is necessary to include at least polyethylene particles in the range of ˜2.0 × 10 7 dyn / cm 2 .
[0007]
The storage elastic modulus (G ′) measured at a frequency of 1 Hz by dynamic viscoelasticity measurement is in the range of 1.0 × 10 6 to 2.0 × 10 7 dyn / cm 2 in the temperature range of 150 to 250 ° C. Polyethylene particles can be suitably used as the porous plastic filter material of the present invention because the fusion strength between the particles is sufficient when sintered and the voids between the particles are not blocked.
[0008]
However, when polyethylene particles having a storage elastic modulus (G ′) as defined above of 2.0 × 10 7 dyn / cm 2 or more are sintered alone, the fusion strength between the particles is small and the porous Since a quality plastic filter cannot be obtained, it is not suitable for the porous plastic filter material of the present invention.
On the other hand, when polyethylene particles having a storage elastic modulus (G ′) of 1.0 × 10 6 dyn / cm 2 or less are sintered alone, the fusion strength between the particles becomes strong. Since clogging is likely to occur and, as a result, the pressure loss becomes large and is not preferable in terms of filter performance, it is likewise not suitable for the porous plastic filter material of the present invention.
[0009]
Polyethylene particles having a storage elastic modulus in the range of 1.0 × 10 6 to 2.0 × 10 7 dyn / cm 2 are used, and the storage elastic modulus (G ′) is 2.0 × 10 7 dyn / cm 2. It may be used by blending with the above polyethylene particles, and the storage elastic modulus (G ′) at that time is in the range of 1.0 × 10 6 to 2.0 × 10 7 dyn / cm 2 . The ratio is preferably 10 wt% or more, more preferably 20 wt% or more.
When the storage elastic modulus (G ′) is within the range of 1.0 × 10 6 to 2.0 × 10 7 dyn / cm 2 , the content of the polyethylene particles is 10 wt% or less, and the effect of blending is small and expected. The improvement in strength cannot be expected.
[0010]
In addition, the form of the thermoplastic material used in the present invention is preferably in the form of powder, and the average particle diameter may be in the range of 50 to 700 μm, preferably 60 to 500 μm. Bring.
When the average particle size is 50 μm or less, the filtration accuracy is improved, but the pressure loss increases when the powder passes, which is not preferable. Moreover, when the average particle diameter is 700 μm or more, satisfactory filtration accuracy cannot be obtained, which is not preferable.
[0011]
Further, the method for sintering and molding the porous filter of the present invention is not particularly limited, and is usually a so-called in-mold sintering method.
That is, the porous filter molding method of the present invention is a molding die comprising an outer mold having an inner surface shape such as a cylindrical shape, and an inner mold having a similar outer surface shape inserted into the outer mold. A static molding method in which a mold is used to fill a cavity formed in a gap between the inner surface of the outer mold and the outer surface of the inner mold with a thermoplastic, and then heated together with the molding die can be suitably employed.
In some cases, a plastic filter can be continuously formed by a ram extrusion method using a ram type extruder having a piston built in a cylinder or an extrusion method using an extruder having a screw incorporated in a cylinder. .
[0012]
【Example】
Examples of the present invention will be specifically described below in comparison with comparative examples.
The particles used for sintering and the porous plastic filter were evaluated by the following method.
[0013]
Measurement of storage elastic modulus A sheet prepared under press molding conditions of 200 ° C. × 30 min × 30 kg / cm 2 was cut into a 45 mm × 12 mm (thickness 2 mm) strip, and the rate of temperature increase was 2 by dynamic viscoelasticity measurement. The storage elastic modulus (G ′) of 30 to 250 ° C. was measured in a nitrogen atmosphere at ° C./min, frequency: 1 Hz.
[0014]
Tensile strength of filter A numerical value obtained by collecting a dumbbell-shaped No. 3 test piece described in JIS K-6251 from a filter and measuring it at room temperature (23 ° C.) at a tensile rate of 5 mm / min.
[0015]
The porosity of the filter The apparent density of the filter was determined by the following formula (1), and the porosity of the filter was calculated by the following formula (2).
○ Apparent density (ρ 1 ) (g / cm 3 ) = W / V ( 1 )
Where W: mass of the plastic filter (g), V: volume of the plastic filter (cm 3 ).
○ Porosity (%) = {(ρ 0 −ρ 1 ) / ρ 0 } × 100 (2)
Where ρ 0 is the true density (g / cm 3 ) of the thermoplastic material constituting the plastic filter.
[0016]
Pressure loss of filter A hollow cylindrical porous plastic filter is fitted with a manometer in one opening of the hollow cylinder and a vacuum pump in the other opening. The air was sucked so as to become a predetermined flow rate (1 m 3 / min, temperature: 23 ° C., pressure 1 atm) per 1 m 2 of the outer surface area, and the pressure difference at that time was measured to obtain a pressure loss (mmAq).
[0017]
Backwash durability evaluation <br/> filters filter was set in a dust collector, pressure: supply 6 kg / cm 2 of air in the interior of the pulse to the filter backwash number: 100 million times (about 6 years Durability test (equivalent to use) was performed, and the presence or absence of cracks or breakage of the filter was visually confirmed. The judgment was “no crack / damage” if there was no crack / breakage, and when crack / breakage occurred, the number of backwashes at that time was recorded.
[0018]
Example 1
Polyethylene particles having a storage elastic modulus (G ′) in the temperature range of 150 to 250 ° C. of 5.67 × 10 6 to 6.22 × 10 6 dyn / cm 2 and an average particle size of 130 μm are used, and the filter thickness is A cylindrical mold having a diameter of 3 mm was filled with vibration, heated at 200 ° C. for 30 minutes, and sintered to obtain a cylindrical porous plastic filter having an inner diameter of 50 mm.
Table 1 shows the evaluation of tensile strength, pressure loss, porosity, and backwash durability of this plastic filter.
[0019]
Example 2
Storage elastic modulus (G ′) in the temperature range of 150 to 250 ° C. is 5.67 × 10 6 to 6.22 × 10 6 dyn / cm 2 , polyethylene particles having an average particle size of 130 μm, and 150 to 250 ° C. Polyethylene particles having a storage elastic modulus (G ′) in the temperature range of 2.63 × 10 7 to 2.82 × 10 7 dyn / cm 2 and an average particle diameter of 65 μm are used, and the mixing ratio is 30/70 wt%. After mixing, the tube was vibrated into a cylindrical mold having a filter thickness of 3 mm, sintered at a temperature of 200 ° C. for 30 minutes, and a cylindrical porous plastic filter having an inner diameter of 50 mm was obtained. .
Table 1 shows the evaluation of tensile strength, pressure loss, porosity, and backwash durability of this plastic filter.
[0020]
Comparative Example 1
Polyethylene particles having a storage elastic modulus (G ′) in the temperature range of 150 to 250 ° C. of 2.63 × 10 7 to 2.82 × 10 7 dyn / cm 2 and an average particle diameter of 65 μm are used, and the filter thickness is A cylindrical mold having a diameter of 3 mm was filled with vibration, heated at 200 ° C. for 30 minutes, and sintered to obtain a cylindrical porous plastic filter having an inner diameter of 50 mm.
Table 1 shows the evaluation of the tensile strength, pressure loss, porosity and backwash durability of this plastic filter.
[0021]
Comparative Example 2
Storage elastic modulus (G ′) in the temperature range of 150 to 250 ° C. is 5.67 × 10 6 to 6.22 × 10 6 dyn / cm 2 , polyethylene particles having an average particle size of 130 μm, and 150 to 250 ° C. Polyethylene particles having a storage elastic modulus (G ′) in the temperature range of 2.63 × 10 7 to 2.82 × 10 7 dyn / cm 2 and an average particle diameter of 65 μm are used, and the mixing ratio is 5/95 wt%. After mixing, the tube was vibrated into a cylindrical mold having a filter thickness of 3 mm, sintered at a temperature of 200 ° C. for 30 minutes, and a cylindrical porous plastic filter having an inner diameter of 50 mm was obtained. .
Table 1 shows the evaluation of tensile strength, pressure loss, porosity, and backwash durability of this plastic filter.
[0022]
[Table 1]
As shown in Table 1, in Examples 1 and 2, there was no problem in backwash durability, and the value of pressure loss was at a level with no practical problem.
On the other hand, in Comparative Examples 1 and 2, the pressure loss was low, but the filter was damaged by backwashing about 40 to 450,000 times, and there was a problem in long-term durability.
[0024]
【The invention's effect】
As described above, the porous plastic filter according to the present invention is a porous plastic filter having no problem in backwash durability and having no practical problem in terms of pressure loss.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14419599A JP3681575B2 (en) | 1999-05-25 | 1999-05-25 | Porous plastic filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14419599A JP3681575B2 (en) | 1999-05-25 | 1999-05-25 | Porous plastic filter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000325715A JP2000325715A (en) | 2000-11-28 |
| JP3681575B2 true JP3681575B2 (en) | 2005-08-10 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14419599A Expired - Lifetime JP3681575B2 (en) | 1999-05-25 | 1999-05-25 | Porous plastic filter |
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| Country | Link |
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| JP (1) | JP3681575B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006007078A (en) * | 2004-06-24 | 2006-01-12 | Kurita Water Ind Ltd | Water collecting pipe, water collecting pipe unit, and filtering device |
| US10711238B2 (en) | 2012-10-02 | 2020-07-14 | Repligen Corporation | Method for proliferation of cells within a bioreactor using a disposable pumphead and filter assembly |
| KR20220019059A (en) * | 2016-04-11 | 2022-02-15 | 스펙트럼, 인크. | Thick wall hollow fiber tangential flow filter |
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1999
- 1999-05-25 JP JP14419599A patent/JP3681575B2/en not_active Expired - Lifetime
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| JP2000325715A (en) | 2000-11-28 |
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