JPH09110968A - Polymeric electret material and its production - Google Patents
Polymeric electret material and its productionInfo
- Publication number
- JPH09110968A JPH09110968A JP27155995A JP27155995A JPH09110968A JP H09110968 A JPH09110968 A JP H09110968A JP 27155995 A JP27155995 A JP 27155995A JP 27155995 A JP27155995 A JP 27155995A JP H09110968 A JPH09110968 A JP H09110968A
- Authority
- JP
- Japan
- Prior art keywords
- polylactic acid
- electret material
- melt
- piezoelectric
- cooling
- 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.)
- Granted
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/549—Organic PV cells
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、医用超音波変性
器、音響変性器、超音波応用計測器、圧電振動子、圧電
トランス、遅延装置、光検知器、光センサー、焦電ビジ
コン、メモリー、エレクトレットフィルター、等の分野
に用途が見込まれる高分子エレクトレット材料に関する
ものである。TECHNICAL FIELD The present invention relates to a medical ultrasonic modifier, an acoustic modifier, an ultrasonic measuring instrument, a piezoelectric vibrator, a piezoelectric transformer, a delay device, a photodetector, an optical sensor, a pyroelectric vidicon, a memory, The present invention relates to a polymer electret material which is expected to be used in the fields of electret filters and the like.
【０００２】[0002]
【従来の技術】現在知られている高分子エレクトレット
材料としては、強誘電型のポリフッ化ビニリデン、フッ
化ビニリデン三フッ化エチレン共重合体、ビニリデンシ
アナイド酢酸ビニル共重合体があるが、これらは、既に
超音波探触子などに使用されている。また、延伸された
ポリ乳酸が、圧電性を示すことが知られている（特開平
５−１５２６３８）。2. Description of the Related Art Currently known polymer electret materials include ferroelectric polyvinylidene fluoride, vinylidene fluoride trifluoride ethylene copolymer and vinylidene cyanide vinyl acetate copolymer. , Already used for ultrasonic probes. Further, it is known that stretched polylactic acid exhibits piezoelectricity (Japanese Patent Laid-Open No. 5-152638).
【０００３】[0003]
【発明が解決しようとする課題】ポリフッ化ビニリデ
ン、フッ化ビニリデン三フッ化エチレン共重合体、ビニ
リデンシアナイド酢酸ビニル共重合体をエレクトレット
化するためには、電場による双極子の配向及び凍結が必
要である。従って、安定な分極を得るためには延伸処理
とポーリング処理を必要とする。しかしながら、５０℃
以上では脱分極を生じ、熱的に不安定といえる。さら
に、ポリフッ化ビニリデンは、最も圧電性の高い材料で
あるが、誘電率が１３であり、高分子材料の高誘電率で
ある。従って、圧電ｄ定数（単位応力当たりの開放電
圧）は、大きくない。そのため、電気から音響への変換
効率は、良好であるが、音響から電気への変換効率が低
くなる。In order to electretize polyvinylidene fluoride, vinylidene fluoride trifluoride ethylene copolymer and vinylidene cyanide vinyl acetate copolymer, it is necessary to orient and freeze the dipole by an electric field. Is. Therefore, stretching treatment and poling treatment are required to obtain stable polarization. However, 50 ° C
Above, depolarization occurs and it can be said that it is thermally unstable. Further, polyvinylidene fluoride is a material having the highest piezoelectricity, but has a dielectric constant of 13, which is a high dielectric constant of a polymer material. Therefore, the piezoelectric d constant (open circuit voltage per unit stress) is not large. Therefore, the conversion efficiency from electricity to sound is good, but the conversion efficiency from sound to electricity is low.
【０００４】また、ポリ乳酸は延伸処理のみで大きな圧
電性ｄ14を示すことが知られている（特開平５−１５２
６３８）。しかし、延伸処理のみでは、せん断ひずみに
よる圧電効果を生じるが、このモードの圧電効果では、
超音波などの応用はできず、さらに焦電性を示さないこ
とから熱的な応用もできない。Further, it is known that polylactic acid exhibits a large piezoelectricity d 14 only by stretching (Japanese Patent Laid-Open No. 5-152).
638). However, the stretching effect alone produces a piezoelectric effect due to shear strain, but the piezoelectric effect in this mode
It cannot be applied to ultrasonic waves, etc., and cannot be applied thermally as it does not exhibit pyroelectricity.
【０００５】本発明は、上記に鑑みてその目的とされる
ところは、誘電率がポリフッ化ビニリデン等より低く、
圧電性が従来のもと同等もしくはそれ以上であり、しか
も機械的強度が大きく、フィルムから異形物まで種々の
形状のものを得ることができる新規な高分子エレクトレ
ット材料を提供することにある。In view of the above, the present invention is aimed at, and has a dielectric constant lower than that of polyvinylidene fluoride or the like,
It is an object of the present invention to provide a novel polymer electret material which has piezoelectricity equal to or higher than that of the conventional one, has high mechanical strength, and can be obtained in various shapes from a film to an irregular shape.
【０００６】[0006]
【課題を解決するための手段】上記の目的は、ポリ乳酸
の溶融急冷成形物をポーリング処理することによって得
られる高分子エレクトレット材料によって達成される。
本発明に用いるポリ乳酸には、ポリ乳酸（重合度１００
以上）のセグメントを有するブロック共重合体も含む。
ポリ乳酸以外のセグメントとしては、ポリエーテル、ポ
リエステル、ポリカーボネート、ポリアミド等の縮合系
高分子を用いることができる。The above objects are achieved by a polymer electret material obtained by poling a melt-quenched product of polylactic acid.
The polylactic acid used in the present invention includes polylactic acid (polymerization degree: 100
Also included are block copolymers having the above segments.
Condensed polymers such as polyether, polyester, polycarbonate, and polyamide can be used as the segment other than polylactic acid.
【０００７】本発明に用いるポリ乳酸の重合法は特に限
定されない。光学活性を有するＬ体又はＤ体の乳酸から
直接脱水縮合あるいは常法に従って乳酸の環状二量体で
あるラクチドを合成し、そのラクチドを開環重合するこ
とによって得られるものどちらでもよい。このポリ乳酸
は、Ｌ体とＤ体の乳酸のブロックコポリマーであっても
よい。また、乳酸のセグメントを有するブロックポリマ
ーであってもよい。The method for polymerizing the polylactic acid used in the present invention is not particularly limited. It may be either one obtained by synthesizing lactide which is a cyclic dimer of lactic acid by direct dehydration condensation from the optically active L- or D-form lactic acid or by a conventional method and subjecting the lactide to ring-opening polymerization. The polylactic acid may be a block copolymer of L-form and D-form lactic acid. Further, it may be a block polymer having a lactic acid segment.
【０００８】このポリマーは、延伸処理のみで大きな圧
電性ｄ14を示すことが知られている（特開平５−１５２
６３８）。しかし、非極性結晶であるがゆえ電界によっ
て双極子が配向するような強誘電的性質を示すことは知
られていなかった。ところが、分子量及び溶融成形条件
を選ぶことにより強誘電体的性質をもつことが明らかに
なった。It is known that this polymer exhibits a large piezoelectricity d 14 only by stretching treatment (Japanese Patent Laid-Open No. 5-152).
638). However, since it is a non-polar crystal, it has not been known that it exhibits ferroelectric properties such that dipoles are oriented by an electric field. However, it became clear that it has ferroelectric properties by selecting the molecular weight and melt molding conditions.
【０００９】ポリ乳酸の分子量については、溶融成形が
可能な範囲内であれば特に制限されないが、溶融成形時
の分子量低下防止や結晶化速度を遅くするため少なくと
も重量平均分子量が５万以上のポリ乳酸、好ましくは１
０万〜３０万のポリ乳酸を使用するのがよい。The molecular weight of polylactic acid is not particularly limited as long as it is within the range capable of melt molding, but polylactic acid having a weight average molecular weight of at least 50,000 is used to prevent a decrease in molecular weight during melt molding and to slow the crystallization rate. Lactic acid, preferably 1
It is advisable to use from 0,000 to 300,000 polylactic acid.
【００１０】本発明の高分子エレクトレット材料は、上
記のポリ乳酸を原料とし、これを適宜の形状に溶融成形
する。溶融成形条件は、ポリ乳酸の融点ないし２２０℃
の範囲に設定し、その後ガラス転移点（６０℃）以下へ
急冷する。この時結晶を作らないか、または、非常に結
晶化度を下げた状態を実現しなければならない。急冷処
理は、空冷、水冷などいかなる方法を用いてもよい。本
発明の好ましい急冷処理温度は、６０℃以下、より好ま
しくは室温程度の１０〜４０℃である。急冷速度は、５
０℃／ｍｉｎ〜１０００℃／ｍｉｎ、好ましくは２００
℃／ｍｉｎ以上がよい。更に好ましくは、ポリ乳酸の溶
融物の温度（ポリ乳酸の融点〜約２００℃程度）を６０
℃以下に５秒〜５分以内に下げるのがよい。The polymer electret material of the present invention is made by using the above-mentioned polylactic acid as a raw material and melt-molding it into an appropriate shape. Melt molding conditions are the melting point of polylactic acid or 220 ° C.
Then, the temperature is rapidly cooled to below the glass transition point (60 ° C.). At this time, crystals should not be formed, or a state in which crystallinity is extremely lowered must be realized. For the rapid cooling treatment, any method such as air cooling or water cooling may be used. The preferred quenching temperature of the present invention is 60 ° C. or lower, more preferably 10 to 40 ° C., which is about room temperature. Quenching speed is 5
0 ° C / min to 1000 ° C / min, preferably 200
C./min or higher is preferable. More preferably, the temperature of the melt of polylactic acid (from the melting point of polylactic acid to about 200 ° C.) is 60.
It is better to lower the temperature below 5 ° C within 5 seconds to 5 minutes.
【００１１】上記のようにして得られたロッド状、帯板
状、フィルム状、繊維状のポリ乳酸成形物は、分子双極
子が無配向であるためエレクトレット特性を示さない。
そこでポーリング処理を行わなければならない。この処
理は、６０〜１８０℃、好ましくは、８０〜１６０℃
で，１０〜１００ＭＶ／ｍの電界を印加する。The rod-shaped, strip-shaped, film-shaped, and fiber-shaped polylactic acid moldings obtained as described above do not exhibit electret characteristics because the molecular dipoles are not oriented.
Therefore, polling processing must be performed. This treatment is performed at 60 to 180 ° C, preferably 80 to 160 ° C.
Then, an electric field of 10 to 100 MV / m is applied.
【００１２】以上のような本発明の高分子エレクトレッ
ト材料は、ポリ乳酸の結晶中のＣ＝Ｏ双極子が電界方向
に配向し、極性結晶を形成し安定な分極をつくることに
特徴がある。このようなエレクトレットは、従来の高分
子圧電材料と同等若しくはそれ以上の圧焦電性を示す。
また、誘電率が低いため、圧電ｇ定数が大きく、強誘電
体型のポリフッ化ビニリデンより高い電圧感度が得られ
る。The polymer electret material of the present invention as described above is characterized in that the C═O dipole in the polylactic acid crystal is oriented in the direction of the electric field to form a polar crystal and form stable polarization. Such an electret exhibits a piezoelectric and pyroelectric property equal to or higher than that of a conventional polymer piezoelectric material.
Further, since the dielectric constant is low, the piezoelectric g constant is large, and higher voltage sensitivity than that of the ferroelectric type polyvinylidene fluoride can be obtained.
【００１３】[0013]
【実施例】次に本発明の高分子エレクトレット材料の実
施例について説明する。重量平均分子量が２０万のポリ
Ｌ−乳酸を溶融後急冷しアモルファスのフィルムを得
た。溶融急冷条件は、ポリＬ−乳酸を２００℃で溶融し
て、３０秒で２０℃まで温度を下げた。この急冷は、水
を用いて行った。EXAMPLES Next, examples of the polymer electret material of the present invention will be described. Poly L-lactic acid having a weight average molecular weight of 200,000 was melted and then rapidly cooled to obtain an amorphous film. As for the melt quenching condition, poly L-lactic acid was melted at 200 ° C., and the temperature was lowered to 20 ° C. in 30 seconds. This quenching was performed using water.
【００１４】得られたフィルムを３〜４cm幅にカット
し、１０８℃に設定された恒温室の窒素中に該フィルム
をセットし、電界１００ＭＶ／ｍを印加した。このフィ
ルムを長さ２cm、幅１cmに切断して試験片を作製し、１
KHz における厚みの変化から圧電率を、またパルス状レ
ーザー光（６７０nm）を試料に照射し、この時の電流出
力から焦電率を算出した。その結果を図１に示す。The obtained film was cut into a width of 3 to 4 cm, the film was set in nitrogen in a thermostatic chamber set at 108 ° C., and an electric field of 100 MV / m was applied. This film is cut into a piece of 2 cm in length and 1 cm in width to prepare a test piece.
The piezoelectric constant was calculated from the change in thickness at KHz, and the sample was irradiated with pulsed laser light (670 nm), and the pyroelectric ratio was calculated from the current output at this time. The result is shown in FIG.
【００１５】図１は、圧電ｄ定数と焦電率βの温度スペ
クトルである。図１より３０〜１７０℃の測定温度域に
おいて、応力あたりの圧電率ｄ33は、およそ１５×１０
-12Ｃ／Ｎの値を示した。温度特性は、ほぼフラットで
ある。FIG. 1 is a temperature spectrum of the piezoelectric d constant and the pyroelectric coefficient β. From FIG. 1, in the measurement temperature range of 30 to 170 ° C., the piezoelectric constant d 33 per stress is about 15 × 10.
The value of -12 C / N was shown. The temperature characteristic is almost flat.
【００１６】図２は、この試料の１１０℃におけるＤ−
Ｅヒテリシス曲線である。一般の強誘電体のようにふる
まうことがわかる。FIG. 2 shows the D- of this sample at 110.degree.
It is an E hysteresis curve. It turns out that it behaves like a general ferroelectric substance.
【００１７】図３は、電解印加によるＸ線回折の変化で
ある。主回折曲線は、大きく変化し、電界により極性結
晶へ転移していることがうかがえる。従って、ここで強
誘電体的挙動により分極が形成し、大きなエレクトレッ
ト特性（圧電焦電性）が得られたと考えられる。FIG. 3 shows changes in X-ray diffraction due to the application of electrolysis. It can be seen that the main diffraction curve changes greatly and is transformed into a polar crystal by the electric field. Therefore, it is considered that the polarization was formed here by the ferroelectric behavior and a large electret characteristic (piezoelectric pyroelectricity) was obtained.
【００１８】[0018]
【発明の効果】このような効果を有する本発明の高分子
エレクトレット材料は、医用超音波変性器、音響変性
器、超音波応用計測器、圧電振動子、圧電トランス、遅
延装置、光検知器、光センサー、焦電ビジコン、メモリ
ー、エレクトレットフィルター、等への応用が見込まれ
る。また、骨成長促進効果を有する骨接合材として応用
することが可能である。The polymer electret material of the present invention having such effects is a medical ultrasonic modifier, acoustic modifier, ultrasonic applied measuring instrument, piezoelectric vibrator, piezoelectric transformer, delay device, photodetector, Applications to optical sensors, pyroelectric vidicons, memories, electret filters, etc. are expected. Further, it can be applied as a bone bonding material having a bone growth promoting effect.
【図１】本発明の高分子エレクトレット材料の圧電ｄ定
数と焦電率βと温度の関係を示すグラフである。FIG. 1 is a graph showing the relationship between the piezoelectric d constant, the pyroelectric constant β, and the temperature of the polymer electret material of the present invention.
【図２】本発明の高分子エレクトレット材料の圧電変位
−電界特性である（ＤＥヒテリシス）。FIG. 2 is a piezoelectric displacement-electric field characteristic of the polymer electret material of the present invention (DE hysteresis).
【図３】本発明の高分子エレクトレット材料の電界によ
る構造変化をＸ線回折により調べたものである。FIG. 3 is a diagram in which a structural change of a polymer electret material of the present invention by an electric field is examined by X-ray diffraction.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｈ０１Ｌ 41/26 Ｈ０１Ｌ 41/22 Ｃ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification number Office reference number FI technical display location H01L 41/26 H01L 41/22 C
Claims (4)
レクトレット材料。1. An electret material obtained by subjecting polylactic acid to melt quenching and polarization treatment.
る高分子エレクトレット材料の製造方法。2. A method for producing a polymer electret material, which comprises subjecting polylactic acid to melt quenching and then polarization treatment.
０℃／ｍｉｎである請求項２記載の高分子エレクトレッ
ト材料の製造方法。3. The melt quenching rate is 50 ° C./min to 100.
The method for producing a polymer electret material according to claim 2, wherein the temperature is 0 ° C./min.
０〜１００ＭＶ／ｍで行う請求項２、３記載の高分子エ
レクトレット材料の製造方法。4. The polarization treatment is performed at a temperature of 60 to 180 ° C. and an electric field of 1.
The method for producing a polymer electret material according to claim 2, wherein the method is performed at 0 to 100 MV / m.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27155995A JP3470471B2 (en) | 1995-10-19 | 1995-10-19 | Polymer electret material and method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27155995A JP3470471B2 (en) | 1995-10-19 | 1995-10-19 | Polymer electret material and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09110968A true JPH09110968A (en) | 1997-04-28 |
| JP3470471B2 JP3470471B2 (en) | 2003-11-25 |
Family
ID=17501771
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27155995A Expired - Fee Related JP3470471B2 (en) | 1995-10-19 | 1995-10-19 | Polymer electret material and method for producing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3470471B2 (en) |
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-
1995
- 1995-10-19 JP JP27155995A patent/JP3470471B2/en not_active Expired - Fee Related
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|---|---|---|---|---|
| CN1309448C (en) * | 2002-05-20 | 2007-04-11 | 东洋纺织株式会社 | Shaped fibrous sheet and filter unit |
| EP1510241A1 (en) * | 2002-06-06 | 2005-03-02 | Toyo Boseki Kabushiki Kaisha | Electret filter and process for producing the same |
| EP1510241A4 (en) * | 2002-06-06 | 2005-08-17 | Toyo Boseki | Electret filter and process for producing the same |
| CN100339148C (en) * | 2002-06-06 | 2007-09-26 | 东洋纺织株式会社 | Electret filter and process for producing the same |
| JP2004057976A (en) * | 2002-07-30 | 2004-02-26 | Toyobo Co Ltd | Electret filter medium having bio-degradability and its manufacturing method |
| JP2010109121A (en) * | 2008-10-30 | 2010-05-13 | Tokai Rubber Ind Ltd | Dielectric film, actuator using the same, sensor, and transducer |
| JP5318203B2 (en) * | 2009-06-15 | 2013-10-16 | 株式会社村田製作所 | Piezoelectric sheet, and method and apparatus for manufacturing a piezoelectric sheet |
| US9537084B2 (en) | 2009-06-15 | 2017-01-03 | Murata Manufacturing Co., Ltd. | Piezoelectric sheet, method for manufacturing piezoelectric sheet, and manufacturing apparatus |
| US9711710B2 (en) | 2009-06-15 | 2017-07-18 | Murata Manufacturing Co., Ltd. | Piezoelectric sheet, method for manufacturing piezoelectric sheet, and manufacturing apparatus |
| JPWO2010147074A1 (en) * | 2009-06-15 | 2012-12-06 | 株式会社村田製作所 | Piezoelectric sheet, and method and apparatus for manufacturing a piezoelectric sheet |
| WO2010147074A1 (en) * | 2009-06-15 | 2010-12-23 | 株式会社村田製作所 | Piezoelectric sheet, method for manufacturing piezoelectric sheet, and manufacturing apparatus |
| US9048426B2 (en) | 2009-06-15 | 2015-06-02 | Murata Manufacturing Co., Ltd. | Piezoelectric sheet, method for manufacturing piezoelectric sheet, and manufacturing apparatus |
| US9136461B2 (en) | 2011-10-13 | 2015-09-15 | Mitsui Chemicals, Inc. | Polymeric piezoelectric material and process for producing the same |
| JP5259026B1 (en) * | 2011-10-13 | 2013-08-07 | 三井化学株式会社 | Polymer piezoelectric material and manufacturing method thereof |
| US9559289B2 (en) | 2011-10-13 | 2017-01-31 | Mitsui Chemicals, Inc. | Polymeric piezoelectric material and process for producing the same |
| WO2013054918A1 (en) * | 2011-10-13 | 2013-04-18 | 三井化学株式会社 | Polymer piezoelectric material, and manufacturing method thereof |
| US20150362647A1 (en) * | 2013-02-01 | 2015-12-17 | Murata Manufacturing Co., Ltd. | Display device and laminated optical film |
| US10126473B2 (en) * | 2013-02-01 | 2018-11-13 | Murata Manufacturing Co., Ltd. | Display device and laminated optical film |
| US20160099403A1 (en) * | 2013-04-10 | 2016-04-07 | Mitsui Chemicals, Inc. | Layered body |
| US20160204337A1 (en) * | 2013-09-02 | 2016-07-14 | Mitsui Chemicals, Inc. | Layered body |
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