JP2766530B2 - Method for producing pitch-based carbon fiber - Google Patents
Method for producing pitch-based carbon fiberInfo
- Publication number
- JP2766530B2 JP2766530B2 JP30328089A JP30328089A JP2766530B2 JP 2766530 B2 JP2766530 B2 JP 2766530B2 JP 30328089 A JP30328089 A JP 30328089A JP 30328089 A JP30328089 A JP 30328089A JP 2766530 B2 JP2766530 B2 JP 2766530B2
- Authority
- JP
- Japan
- Prior art keywords
- fiber
- pitch
- carbon fiber
- strength
- temperature
- 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 - Lifetime
Links
Landscapes
- Inorganic Fibers (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は、メソフェーズピッチを出発原料とする、高
強度、高弾性率を有する炭素繊維の製造方法に関する。
より詳しくは炭素繊維表面を改質することにより引張強
度が特に改善された、高強度、高弾性率を有する高性能
ピッチ系炭素繊維を製造する方法に関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a carbon fiber having high strength and a high elastic modulus using mesophase pitch as a starting material.
More specifically, the present invention relates to a method for producing a high-performance pitch-based carbon fiber having a high strength and a high elastic modulus, in which the tensile strength is particularly improved by modifying the surface of the carbon fiber.
従来の技術 炭素繊維は、比強度および比弾性率の高い材料で近
年、航空宇宙分野、自動車工業、その他の工業分野で、
強くて軽い素材として注目を浴びている。このような分
野では、高強度、高弾性率でありながら安価な材料が望
まれている。2. Description of the Related Art Carbon fiber is a material having a high specific strength and a specific elastic modulus in recent years in the aerospace field, the automobile industry, and other industrial fields.
It is attracting attention as a strong and light material. In such a field, an inexpensive material having high strength and high elastic modulus is desired.
現在、炭素繊維は、ポリアクリルニトリル(PAN)を
主原料とするPAN系炭素繊維と、ピッチ類を原料とする
ピッチ系炭素繊維が製造されているが、現状では高強
度、高弾性率の高性能炭素繊維としては、主にPAN系炭
素繊維が使用されている。At present, PAN-based carbon fibers made mainly from polyacrylonitrile (PAN) and pitch-based carbon fibers made from pitches are manufactured as carbon fibers, but at present, high strength and high elastic modulus are required. As the performance carbon fiber, PAN-based carbon fiber is mainly used.
しかしながら、PAN系炭素繊維は、さらに高弾性率化
をするには限界があり、また、その原料となるPANが高
価であり、PANから得られる炭素繊維収率が低いことな
どもあって、炭素繊維の価格が高価とならざるを得ない
という問題がある。However, PAN-based carbon fibers have a limit in further increasing the modulus of elasticity, and PAN as a raw material is expensive, and the carbon fiber yield obtained from PAN is low. There is a problem that the price of the fiber must be expensive.
そこで、近年、炭素繊維収率が高く、高弾性率化が容
易なメソフェーズピッチを原料とするピッチ系炭素繊維
の高性能化の検討が種々行なわれている。Therefore, in recent years, various studies have been made on improving the performance of pitch-based carbon fibers using mesophase pitch as a raw material, in which the yield of carbon fibers is high and the elastic modulus can be easily increased.
メソフェーズピッチ系炭素繊維の高性能化について
は、主に、紡糸用ピッチ性状に関するもの、紡糸条件、
紡糸装置に関するもの、不融化、炭化、黒鉛化条件に関
するものが提案されている。特にメソフェーズピッチ系
炭素繊維に特有な問題として、原料ピッチの配向性が高
いため、通常の方法で溶融紡糸して得られる炭素繊維
が、一般にラジアル型と呼ばれる繊維断面構造をとり易
く、このため炭化、黒鉛化時に表面欠陥を生じ易く、引
張強度の点でPAN系炭素繊維に対して見劣りがすること
が指摘されている。Regarding high performance of mesophase pitch-based carbon fiber, mainly related to pitch properties for spinning, spinning conditions,
A proposal relating to a spinning apparatus and a proposal relating to infusibilization, carbonization and graphitization conditions have been proposed. In particular, as a problem peculiar to mesophase pitch-based carbon fibers, since the orientation of the raw material pitch is high, carbon fibers obtained by melt-spinning by a usual method are likely to have a fiber cross-sectional structure generally called a radial type. It has been pointed out that surface defects easily occur during graphitization and are inferior to PAN-based carbon fibers in terms of tensile strength.
そこで、かかる表面欠陥を低下させるために、各種紡
糸方法、および炭素繊維の表面処理方法等が提案されて
いる。In order to reduce such surface defects, various spinning methods, carbon fiber surface treatment methods, and the like have been proposed.
例えばピッチ系炭素繊維の表面を処理することによっ
て表面欠陥を低下させる方法としては、特開昭61−2157
16号公報に記載されているような、炭素繊維表面を酸素
を用いて気相酸化エッチングすることによって、炭素繊
維表面の欠陥を低下させることからなる炭素繊維の引張
強度ならびに弾性率を向上させる方法がある。For example, as a method of reducing surface defects by treating the surface of pitch-based carbon fiber, Japanese Patent Application Laid-Open No. 61-2157
A method for improving the tensile strength and elastic modulus of a carbon fiber by reducing defects on the surface of the carbon fiber by subjecting the surface of the carbon fiber to gas-phase oxidative etching using oxygen as described in Japanese Patent No. 16 There is.
しかしながら、この方法では、表面処理後の炭素繊維
の取扱いによって生じる欠陥に対しては効果は全く無
く、また、気相酸化エッチングによって、潜在的に存在
している欠陥をさらに拡大する場合もあり、その効果は
あまり大きなものではなく限定されたものとならざるを
得ない。However, this method has no effect on the defects caused by the handling of the carbon fibers after the surface treatment, and in some cases, the vapor-phase oxidation etching may further expand the potential defects. The effect is not very large and must be limited.
発明が解決しようとする課題 炭素繊維製造工程上で生ずる、潜在的欠陥、あるいは
炭素繊維製造後の取扱いに際して生じる表面欠陥、その
いずれであっても、破壊靭性が向上することによって、
表面欠陥に対する応力集中の緩和あるいは亀裂伝播の阻
害によって、炭素繊維強度の改善が図られる。Problems to be Solved by the Invention Potential defects occurring in the carbon fiber manufacturing process, or surface defects generated during handling after carbon fiber manufacturing, any of which, by improving the fracture toughness,
By relaxing stress concentration on surface defects or inhibiting crack propagation, carbon fiber strength is improved.
本発明の目的は、このような破壊靭性を向上させ、欠
陥に対する強度の低下が緩和された炭素繊維構造を発現
させる、ピッチ系炭素繊維の製造方法を提供せんとする
ものである。An object of the present invention is to provide a method for producing a pitch-based carbon fiber that improves such fracture toughness and develops a carbon fiber structure in which a decrease in strength against defects is reduced.
課題を解決するための手段 そこで、本発明者等は、表面欠陥を生じ易いピッチ系
炭素繊維に関して、表面欠陥に対する応力集中の程度を
軽減させる、あるいは欠陥の亀裂伝播を阻害させる、す
なわち、破壊靭性が改善された炭素繊維とすることによ
って、表面欠陥を生じ易いピッチ系炭素繊維に対して強
度向上を達成されるとの考えに基づいて鋭意検討を行
い、本発明を完成したものである。Means for Solving the Problems In view of the above, the inventors of the present invention have proposed a method of reducing the degree of stress concentration on surface defects or inhibiting the propagation of cracks in defects, with respect to pitch-based carbon fibers, which tend to cause surface defects, that is, fracture toughness. The present inventors have made intensive studies based on the idea that the strength of a pitch-based carbon fiber, which is liable to cause surface defects, can be improved by using a carbon fiber having an improved carbon fiber, thereby completing the present invention.
すなわち、本発明は、メソフェーズを出発原料とする
ピッチ繊維を、酸化性ガス雰囲気下で不融化した不融化
繊維、あるいは前記の不融化繊維を不活性ガス雰囲気下
で炭化した炭化繊維を、水蒸気雰囲気下もしくは5体積
%(モル%)以上の水蒸気を含む混合ガス雰囲気下で、
450℃以上1000℃以下、10秒以上4時間以下で処理した
後、1300℃以上で炭素化、黒鉛化することを特徴とする
ピッチ系炭素繊維の製造方法である。That is, the present invention provides a pitch fiber starting from a mesophase, an infusibilized fiber infusibilized under an oxidizing gas atmosphere, or a carbonized fiber obtained by carbonizing the infusibilized fiber under an inert gas atmosphere, in a steam atmosphere. Under or in a mixed gas atmosphere containing 5% by volume (mol%) or more water vapor,
This is a method for producing pitch-based carbon fibers, which comprises treating at 450 ° C. to 1000 ° C. for 10 seconds to 4 hours, and then carbonizing and graphitizing at 1300 ° C. or more.
以下、本発明の内容を詳細に説明する。 Hereinafter, the contents of the present invention will be described in detail.
本発明で用いるピッチは、コールタールピッチ、SRC
等の石炭系ピッチ、エチレンタールピッチ、流動接触触
媒分解残査油から得られるデカントオイルピッチ等の石
油系ピッチ、あるいはナフタレン等から触媒などを用い
て作られる、合成ピッチ等、各種のピッチを包含するも
のである。The pitch used in the present invention is coal tar pitch, SRC
Includes various pitches, such as coal pitch, ethylene tar pitch, petroleum pitch such as decant oil pitch obtained from fluidized catalytic cracking residue, or synthetic pitch made from catalysts from naphthalene etc. Is what you do.
本発明で使用されるメソフェーズピッチは、前記のピ
ッチを従来公知の方法でメソフェーズを発生させたもの
である。メソフェーズピッチは、紡糸した際のピッチ繊
維の配向性が高いものが望ましく、このためメソフェー
ズ含有量は40%以上、より好ましくは70%以上含有する
ものである。The mesophase pitch used in the present invention is obtained by generating a mesophase from the above-mentioned pitch by a conventionally known method. It is desirable that the mesophase pitch has a high orientation of the pitch fiber when spun. Therefore, the mesophase content is 40% or more, more preferably 70% or more.
また、本発明で用いるメソフェーズピッチは軟化点が
200℃以上400℃以下、より好ましくは250℃以上350℃以
下のものがよい。なお、これらのピッチは紡糸性を向上
させるために、フリーカーボン、灰分などの不純物粒子
を濾過などの周知の方法で予め除去しておくことが望ま
しい。The mesophase pitch used in the present invention has a softening point.
Those having a temperature of 200 ° C to 400 ° C, more preferably 250 ° C to 350 ° C are preferable. In order to improve the spinnability of these pitches, it is desirable to remove impurity particles such as free carbon and ash in advance by a known method such as filtration.
ピッチ繊維は、前記メソフェーズピッチを、これまで
知られている方法にて溶融紡糸を行うことにより得られ
る。例えば、前記メソフェーズピッチを粘度100〜2000
ポイズを示す温度で、口径0.1〜0.5mmのキャピラリーか
ら、圧力0.1〜100kg/cm2程度で押し出しながら100〜200
0m/minの引き取り速度で延伸し、繊維径が5〜20μmの
ピッチ繊維を得る。The pitch fiber is obtained by subjecting the mesophase pitch to melt spinning by a conventionally known method. For example, the mesophase pitch has a viscosity of 100 to 2000.
At a temperature showing the poise, the capillary diameter 0.1 to 0.5 mm, while the extrusion pressure 0.1~100kg / cm 2 100 to 200
Drawing is performed at a take-up speed of 0 m / min to obtain a pitch fiber having a fiber diameter of 5 to 20 μm.
つぎにピッチ繊維は、公知の方法で不融化処理するこ
とにより熱硬化性の繊維へと転換する。例えば、空気、
空気に窒素ガス等の不活性ガス、あるいは酸素等を加え
酸素濃度を制御した酸化性ガス、またはこれらのガス
に、オゾン、二酸化窒素ガス、一酸化窒素ガス、二酸化
硫黄ガス等を混合させた、酸化性ガス雰囲気下でピッチ
の軟化点温度以下から、ピッチ繊維を酸化する不融化処
理を行う。Next, the pitch fiber is converted into a thermosetting fiber by infusibilizing treatment by a known method. For example, air,
Inert gas such as nitrogen gas, or oxidizing gas with oxygen concentration controlled by adding oxygen to air, or ozone, nitrogen dioxide gas, nitrogen monoxide gas, sulfur dioxide gas, etc. An infusibilization treatment for oxidizing the pitch fibers is performed in an oxidizing gas atmosphere from a temperature equal to or lower than the softening point of the pitch.
本発明ではこのようにして得られた不融化繊維、ある
いは不融化繊維を予め窒素ガス等の不活性ガス雰囲気下
で炭化処理した炭化繊維を用いる。なお、本発明に用い
る炭化繊維は温度300℃以上1000℃以下、より好ましく
は300℃以上900℃以下で炭化処理したものがよい。炭化
温度が1000℃を超える場合では本発明による効果は著し
く減ずる。In the present invention, the infusibilized fiber obtained in this manner or a carbonized fiber obtained by previously carbonizing the infusibilized fiber in an atmosphere of an inert gas such as nitrogen gas is used. The carbonized fibers used in the present invention are preferably carbonized at a temperature of 300 ° C. or more and 1000 ° C. or less, more preferably 300 ° C. or more and 900 ° C. or less. When the carbonization temperature exceeds 1000 ° C., the effect of the present invention is significantly reduced.
本発明において、かかる不融化繊維、あるいは炭化繊
維を、水蒸気含有雰囲気下で450℃以上1000℃以下、好
ましくは600℃以上950℃以下の温度で処理し、その後13
00℃以上で炭化、黒鉛化することが重要である。水蒸気
含有雰囲気下での温度が450℃未満では、水蒸気による
反応は非常に遅く実質的な意味を持たない。また、1000
℃超では水蒸気による反応が過大となり、かえって得ら
れる炭素繊維の強度を低下させる。In the present invention, such infusibilized fiber or carbonized fiber is treated at a temperature of 450 ° C. or more and 1000 ° C. or less, preferably 600 ° C. or more and 950 ° C. or less in a steam-containing atmosphere, and thereafter, 13 ° C.
It is important to carbonize and graphitize at 00 ° C or higher. If the temperature in a steam-containing atmosphere is lower than 450 ° C., the reaction with steam is very slow and has no substantial meaning. Also, 1000
When the temperature exceeds ℃, the reaction by water vapor becomes excessive, and the strength of the obtained carbon fiber is rather lowered.
雰囲気ガスは、水蒸気単独でも良いし、水蒸気に窒素
ガスなどの非酸化性ガスを混合した混合ガスでもよい。
このときの水蒸気濃度は5体積%以上、より好ましくは
20体積%以上がよい。5体積%未満では水蒸気濃度が低
すぎ反応に長時間を要するようになり、また炭素繊維の
引張強度の改善効果が少ない。The atmosphere gas may be steam alone or a mixed gas obtained by mixing steam with a non-oxidizing gas such as nitrogen gas.
The water vapor concentration at this time is 5% by volume or more, more preferably
20 volume% or more is good. If it is less than 5% by volume, the water vapor concentration is so low that a long time is required for the reaction, and the effect of improving the tensile strength of the carbon fiber is small.
水蒸気によって処理する時間は処理温度、あるいは本
発明に用いる繊維種によっても異なるが、通常10秒以上
4時間以下、好ましくは1時間以下、より好ましくは20
秒以上30分以下がよい。4時間を超える場合は処理に時
間を要し過ぎ、処理費用がかさむだけではなく、局所的
に反応が進みすぎ本発明による効果が現われないばかり
か、逆に得られる炭素繊維の引張強度が低下する。ま
た、処理時間が10秒未満では反応が不足する、あるいは
繊維間での反応にむらが生じ好ましくない。The time of the treatment with steam varies depending on the treatment temperature or the type of fiber used in the present invention, but it is usually from 10 seconds to 4 hours, preferably 1 hour or less, more preferably 20 hours or less.
The time should be between 30 seconds and 30 minutes. When the treatment time is more than 4 hours, the treatment takes too much time, which not only increases the treatment cost, but also promotes the reaction locally so that the effect of the present invention does not appear. I do. If the treatment time is less than 10 seconds, the reaction becomes insufficient or the reaction between fibers becomes uneven, which is not preferable.
このようにして得られた処理繊維を、従来公知の方法
で、1300℃以上で炭化、黒鉛化することによって本発明
が達成される。かかる処理繊維の炭化温度が1300℃未満
では、炭素繊維物性の改善は少なく、1300℃以上、好ま
しくは1700℃以上とすることが望ましい。The present invention is achieved by carbonizing and graphitizing the thus-treated fiber at 1300 ° C. or higher by a conventionally known method. When the carbonization temperature of the treated fiber is lower than 1300 ° C., the improvement in the physical properties of the carbon fiber is small, and it is desirable that the temperature is 1300 ° C. or higher, preferably 1700 ° C. or higher.
以上のように、メソフェーズピッチを出発原料とする
ピッチ繊維を、酸化性ガス雰囲気下で不融化した不融化
繊維、あるいはこの不融化繊維を不活性ガス雰囲気下で
炭化した炭化繊維を、水蒸気雰囲気下、もしくは水蒸気
を含む混合ガス雰囲気下、450℃以上1000℃以下で処理
し、その後この処理した繊維を不活性ガス雰囲気中1300
℃以上で炭素化、黒鉛化することによって、破壊靭性が
向上し引張強度が改善された炭素繊維を得ることができ
る。As described above, pitch fibers using mesophase pitch as a starting material, infusibilized fibers infusibilized in an oxidizing gas atmosphere, or carbonized fibers obtained by carbonizing the infusibilized fibers in an inert gas atmosphere, are treated in a steam atmosphere. Alternatively, under a mixed gas atmosphere containing water vapor, the fiber is treated at 450 ° C. or more and 1000 ° C. or less, and then the treated fiber is treated in an inert gas atmosphere at 1300 ° C.
By carbonizing or graphitizing at a temperature of not less than ° C, it is possible to obtain a carbon fiber having improved fracture toughness and improved tensile strength.
作用 本発明において炭素繊維の引張強度が改善される理由
としては、いまだ不明な点も多く定かではないが、以下
のように考えられる。Action The reason why the tensile strength of the carbon fiber is improved in the present invention is as yet unknown, but it is considered as follows.
水蒸気による反応は、活性炭の製造等に用いられるよ
うに、炭素材料に微細な空孔(ミクロポア)を構成す
る。通常このようなミクロポアは炭素繊維強度を低下さ
せることは知られている。本発明に記載される条件下で
水蒸気と反応させた場合、水蒸気によって生じるミクロ
ポアは炭素繊維の表面近傍に限られる。生成されるミク
ロポアが導入された層の厚みは、炭素繊維強度を左右す
る潜在的表面欠陥の深さとほぼ等しいものと考えられ
る。The reaction with water vapor forms fine pores (micropores) in the carbon material as used in the production of activated carbon and the like. It is generally known that such micropores reduce carbon fiber strength. When reacted with steam under the conditions described in the present invention, the micropores generated by the steam are limited to the vicinity of the surface of the carbon fiber. It is considered that the thickness of the layer into which the formed micropores are introduced is substantially equal to the depth of a potential surface defect that affects the strength of the carbon fiber.
このように、水蒸気で処理した繊維は、ミクロポアが
繊維表面に多く、その導入されている厚みは強度を支配
する欠陥相当より小さなものとなっており、繊維断面の
残りの大部分にはミクロポアが導入されない構造をと
る。水蒸気で生じたミクロポアは、このままの状態では
まだ大きなものと考えられ、また繊維自体も炭化がまだ
完全には進行していないため強度の低いものしか得られ
ない。Thus, the fibers treated with water vapor have a large number of micropores on the fiber surface, the introduced thickness is smaller than the defect that governs the strength, and the majority of the fiber cross section has micropores. Take a structure that is not introduced. The micropores generated by the water vapor are considered to be still large in this state, and the fibers themselves have only low strength because carbonization has not yet completely progressed.
この当該繊維を、1300℃以上の温度で炭化、黒鉛化す
ることによって、ミクロポアが導入された繊維表面層は
収縮によってより緻密なものとなり、これ自身の存在に
よって強度低下をもたらすということがなくなる。By carbonizing and graphitizing the fiber at a temperature of 1300 ° C. or higher, the fiber surface layer into which the micropores are introduced becomes denser due to shrinkage, and the presence of the fiber itself does not cause a decrease in strength.
このように強度低下に結びつかないミクロポアが炭素
繊維表面近傍のみに分布することによって潜在的に存在
する強度支配欠陥、あるいは炭素繊維製造後に生じた表
面欠陥に対して、欠陥部分への応力集中が緩和される。
また、このようなミクロポアは、亀裂の成長、伝播に対
して抵抗となる。すなわち、炭素繊維自身の持つ破壊靭
性値を向上させることによって、炭素繊維引張強度が改
善されるものと推定される。As the micropores that do not lead to a decrease in strength are distributed only in the vicinity of the carbon fiber surface, stress concentration at the defect part is reduced for potential strength-controlling defects or surface defects generated after carbon fiber production Is done.
Such micropores also resist crack growth and propagation. That is, it is presumed that the tensile strength of the carbon fiber is improved by improving the fracture toughness value of the carbon fiber itself.
第1図に本発明法による炭素繊維引張強度の変化を示
した。水蒸気雰囲気下での処理温度を一定とし、処理時
間を変化させたときの炭素繊維の引張強度の変化を例示
したが、特定の処理温度における最適な処理時間が存在
することが示されている。同様に特定の処理時間に対す
る最適な処理温度が存在することは明白である。FIG. 1 shows the change in carbon fiber tensile strength according to the method of the present invention. The change in the tensile strength of the carbon fiber when the processing time is changed while the processing temperature in a steam atmosphere is kept constant is illustrated, but it is shown that there is an optimum processing time at a specific processing temperature. It is also clear that there is an optimum processing temperature for a particular processing time.
これは、水蒸気処理によって生じるミクロポアが導入
された層厚みに強度を改善する最適な点が存在するとい
うことであり、処理時間が長くなるにつれ、ミクロポア
導入層は厚くなり、これにしたがい強度も改善される。
さらに処理時間が長くなると潜在的に存在する欠陥の深
さよりもミクロポア導入層が厚くなり、この場合潜在的
欠陥からの亀裂伝播がミクロポアによって促進され強度
が低下すると考えられ、上記に示した本発明による炭素
繊維引張強度の改善理由を示唆する結果となっている。This means that there is an optimum point for improving the strength in the layer thickness in which the micropores generated by the steam treatment are introduced, and the longer the processing time, the thicker the micropore-introduced layer, and the strength improves accordingly. Is done.
When the treatment time is further increased, the micropore introduction layer becomes thicker than the depth of the potentially existing defect. In this case, it is considered that crack propagation from the potential defect is promoted by the micropore and the strength is reduced. The results suggest the reason for the improvement of the carbon fiber tensile strength due to.
ここではミクロポア導入層を一例に挙げたが、強度を
支配するであろうミクロポアの大きさ、あるいは形や量
などについても同様な関係が存在し、特定の処理条件下
で強度が改善されるものと考えられる。Here, the micropore introduction layer is taken as an example, but there is a similar relationship with respect to the size, shape, and amount of the micropores that will govern the strength, and the strength is improved under specific processing conditions. it is conceivable that.
従来、炭素繊維の強度物性の改善方法としては、いか
に欠陥を少なくするかについて検討されてきたが、本発
明は、従来の発想とは全く逆に、炭素繊維にミクロポア
のような微小な欠陥を導入することによって、潜在的に
存在する欠陥に対して応力集中を緩和させたりする効果
によって強度を改善するという、従来にない新規な発想
によるものである。また、その効果が炭化あるいは黒鉛
化繊維製造後に、炭素繊維の取扱い等で生じる欠陥に対
してもその効果を発揮するという特徴を有する。Conventionally, as a method of improving the strength physical properties of carbon fibers, it has been studied how to reduce defects.However, the present invention completely contradicts the conventional idea to remove minute defects such as micropores into carbon fibers. This is based on a novel concept that has not been used in the past, in which the strength is improved by the effect of reducing the stress concentration with respect to a potential defect by the introduction. Further, it is characterized in that the effect is exerted also on defects caused by the handling of carbon fibers after the production of carbonized or graphitized fibers.
実施例 以下、本発明を実施例ならびに比較例を用いて説明す
る。なお、本発明において、ピッチ系炭素繊維および原
料ピッチの特性を表わすのに用いた諸物性値は以下の定
義によった。Examples Hereinafter, the present invention will be described with reference to Examples and Comparative Examples. In the present invention, various physical property values used to represent the characteristics of the pitch-based carbon fiber and the raw material pitch are defined as follows.
(1)引張強度、引張弾性率 引張強度、引張弾性率はJIS−R−7601(1986年)に
示された方法に準じて測定した。(1) Tensile strength and tensile elastic modulus Tensile strength and tensile elastic modulus were measured according to the method shown in JIS-R-7601 (1986).
(2)粘度、軟化点 粘度は、同心回転二重円筒粘度計を用いて測定した。
軟化点は、フローテスターを用いてハーゲン・ポアズイ
ユ式から算出される見掛けの粘度が20,000ポイズとなる
温度である。(2) Viscosity and softening point The viscosity was measured using a concentric rotating double cylinder viscometer.
The softening point is the temperature at which the apparent viscosity calculated from the Hagen-Poiseuille equation using a flow tester is 20,000 poise.
(3)メソフェーズ含有量 本発明でいうメソフェーズとは、冷却固化したピッチ
を樹脂等に埋込んで表面を研磨し、反射偏光顕微鏡を用
いて観察することによって決定できる光学的に異方性を
示す組織を指す。またメソフェーズ含有量とは、前述の
ようにして観察して認められる異方性組織の面積割合で
示す。(3) Mesophase content The mesophase as referred to in the present invention refers to an optically anisotropic which can be determined by embedding a cooled and solidified pitch in a resin or the like, polishing the surface, and observing it with a reflection polarization microscope. Refers to the organization. The mesophase content is indicated by the area ratio of the anisotropic structure observed and observed as described above.
(4)トルエン不溶分、キノリン不溶分 トルエン不溶分、キノリン不溶分はJIS−K−2425(1
978年)に示された方法に準じて測定した。(4) Toluene-insoluble matter and quinoline-insoluble matter Toluene-insoluble matter and quinoline-insoluble matter are JIS-K-2425 (1
978).
実施例1 原料として軟化点80℃の脱QIされたコールタールピッ
チを、水素化溶媒としてテトラヒドロキノリンを用い、
120kgf/cm2の圧力下440℃で20分間反応させた後、減圧
化270℃で溶媒および低沸点留分を除き、水素化処理ピ
ッチを得た。これを常圧下480℃で熱処理した後、低沸
点分を除きメソフェーズピッチを得た。このピッチは、
軟化点が304℃、トルエン不溶解分が85重量%、キノリ
ン不溶解分が14重量%、メソフェーズ含有量が95%であ
った。Example 1 Using decoaled coal tar pitch having a softening point of 80 ° C. as a raw material and tetrahydroquinoline as a hydrogenation solvent,
After reacting at 440 ° C. for 20 minutes under a pressure of 120 kgf / cm 2 , the solvent and low boiling fractions were removed at 270 ° C. under reduced pressure to obtain a hydrotreated pitch. After heat-treating this at 480 ° C. under normal pressure, a mesophase pitch was obtained except for a low boiling point component. This pitch is
The softening point was 304 ° C, the toluene-insoluble content was 85% by weight, the quinoline-insoluble content was 14% by weight, and the mesophase content was 95%.
このメソフェーズピッチを温度340℃粘度100ポイズで
精密濾過網を用いてピッチ中の不融異物を除去した。こ
のピッチを用いて従来公知の方法で、キャピラリー径0.
14mm、ノズルホール数3,000のノズルパックを有する紡
糸機を用いて、メソフェーズピッチの粘度800ポイズで
糸径13μmのピッチ繊維を得た。This mesophase pitch was removed at a temperature of 340 ° C. and a viscosity of 100 poise using a microfiltration net to remove infusible foreign matter in the pitch. Using this pitch in a conventionally known method, a capillary diameter of 0.
Using a spinning machine having a nozzle pack with 14 mm and 3,000 nozzle holes, pitch fibers having a mesophase pitch viscosity of 800 poise and a yarn diameter of 13 μm were obtained.
このピッチ繊維を、空気中で200℃から300℃まで、0.
5℃/minの昇温速度で昇温し、そのまま300℃に1時間保
持し不融化処理を行い不融化繊維を得た。この不融化繊
維を窒素ガス雰囲気下、300℃から500℃まで5℃/minで
昇温し、そのまま500℃に30分保持して炭化繊維を得
た。This pitch fiber is heated from 200 ° C to 300 ° C in the air at 0.
The temperature was raised at a rate of 5 ° C./min, and the temperature was maintained at 300 ° C. for 1 hour to perform an infusibilization treatment to obtain an infusible fiber. The infusible fiber was heated from 300 ° C. to 500 ° C. at a rate of 5 ° C./min in a nitrogen gas atmosphere, and kept at 500 ° C. for 30 minutes to obtain a carbonized fiber.
つぎにこの炭化繊維を水蒸気50体積%と窒素ガス50体
積%の混合ガス雰囲気下850℃の炉内で1.5、2.5、3、
4、5、10、15分でそれぞれ処理し、7種類の処理繊維
を得た。その後、これらの処理繊維を各々アルゴンガス
雰囲気下で昇温速度40℃/minで2000℃まで昇温し、その
まま2000℃に15分保持して8種類の黒鉛化繊維を得た。Next, the carbonized fibers were placed in a furnace at 850 ° C. in a mixed gas atmosphere of 50% by volume of steam and 50% by volume of nitrogen gas at 1.5, 2.5, 3,
The treatment was performed for 4, 5, 10, and 15 minutes, respectively, to obtain seven types of treated fibers. Thereafter, each of these treated fibers was heated to 2000 ° C. at a rate of 40 ° C./min in an argon gas atmosphere, and kept at 2000 ° C. for 15 minutes to obtain eight types of graphitized fibers.
得られた各々の黒鉛化繊維の引張強度を第1図に示し
た。850℃、1.5分で水蒸気処理したものは引張強度およ
び引張弾性率は糸径10μm、強度310kgf/mm2、弾性率50
tf/mm2であった。FIG. 1 shows the tensile strength of each of the obtained graphitized fibers. Those subjected to steam treatment at 850 ° C. for 1.5 minutes have a tensile strength and tensile elastic modulus of 10 μm in yarn diameter, a strength of 310 kgf / mm 2 , and an elastic modulus of 50.
tf / mm 2 .
実施例2 実施例1で温度850℃、時間1.5分で水蒸気処理した処
理繊維を、アルゴンガス雰囲気下で昇温速度40℃/minで
1500℃まで昇温し、そのまま1500℃に15分保持して炭素
繊維を得た。得られた炭素繊維の引張強度および弾性率
を測定したところ、糸径10.7μm、強度220kg/mm2、弾
性率31tf/mm2であった。Example 2 The treated fiber subjected to steam treatment at a temperature of 850 ° C. for 1.5 minutes in Example 1 was heated at a rate of 40 ° C./min in an argon gas atmosphere.
The temperature was raised to 1500 ° C, and kept at 1500 ° C for 15 minutes to obtain carbon fibers. When the tensile strength and the elastic modulus of the obtained carbon fiber were measured, the yarn diameter was 10.7 μm, the strength was 220 kg / mm 2 , and the elastic modulus was 31 tf / mm 2 .
実施例3 実施例1で用いた不融化繊維を、水蒸気100体積%の
雰囲気下温度500℃の炉内に装入し、続いて500℃から83
0℃まで25℃/minで昇温し、そのまま5分処理した。そ
の後、この処理繊維をアルゴンガス雰囲気下で昇温速度
40℃/minで2000℃まで昇温し、そのまま15分保持して黒
鉛化繊維を得た。得られた黒鉛化繊維の引張強度および
引張弾性率を測定したところ、糸径10μm、強度300kgf
/mm2、弾性率50tf/mm2であった。Example 3 The infusibilized fiber used in Example 1 was charged into a furnace at a temperature of 500 ° C. under an atmosphere of 100% by volume of water vapor.
The temperature was raised to 0 ° C at a rate of 25 ° C / min, and the treatment was continued for 5 minutes. Thereafter, the temperature of the treated fiber is increased in an argon gas atmosphere.
The temperature was raised to 2000 ° C. at 40 ° C./min, and kept for 15 minutes to obtain a graphitized fiber. When the tensile strength and tensile modulus of the obtained graphitized fiber were measured, the yarn diameter was 10 μm, and the strength was 300 kgf.
/ mm 2 and the elastic modulus was 50 tf / mm 2 .
比較例1 実施例1で用いた不融化繊維を窒素ガス雰囲気下で30
0℃から400℃まで5℃/minで昇温し、そのまま400℃に3
0分保持して炭化繊維を得た。つぎにこの炭化繊維をア
ルゴンガス雰囲気下で昇温速度40℃/minで2000℃まで昇
温し、そのまま2000℃に15分保持して黒鉛化繊維を得
た。得られた黒鉛化繊維の引張強度および引張弾性率を
測定したところ、糸径10μm、強度240kgf/mm2、弾性率
50tf/mm2であった。Comparative Example 1 The infusibilized fiber used in Example 1 was treated under a nitrogen gas atmosphere for 30 minutes.
The temperature is raised from 0 ° C to 400 ° C at 5 ° C / min, and
After holding for 0 minutes, a carbonized fiber was obtained. Next, the carbonized fiber was heated to 2000 ° C. at a rate of 40 ° C./min in an argon gas atmosphere, and kept at 2000 ° C. for 15 minutes to obtain a graphitized fiber. When the tensile strength and the tensile elastic modulus of the obtained graphitized fiber were measured, the yarn diameter was 10 μm, the strength was 240 kgf / mm 2 , and the elastic modulus was
It was 50 tf / mm 2 .
比較例2 比較例1で得た炭化繊維をアルゴンガス雰囲気下で昇
温速度40℃/minで1500℃まで昇温し、そのまま1500℃に
15分保持して炭素繊維を得た。得られた炭素繊維の引張
強度および弾性率を測定したところ、糸径10.7μm、強
度190kg/mm2、弾性率30tf/mm2であった。Comparative Example 2 The carbonized fiber obtained in Comparative Example 1 was heated to 1500 ° C. at a heating rate of 40 ° C./min in an argon gas atmosphere, and was directly heated to 1500 ° C.
After holding for 15 minutes, a carbon fiber was obtained. When the tensile strength and the elastic modulus of the obtained carbon fiber were measured, the yarn diameter was 10.7 μm, the strength was 190 kg / mm 2 , and the elastic modulus was 30 tf / mm 2 .
比較例3 実施例1で用いた不融化繊維を水蒸気50体積%と窒素
ガス50体積%の混合ガス雰囲気下、300℃から400℃まで
5℃/minで昇温し、そのまま400℃に1時間保持して処
理繊維を得た。つぎにこの処理繊維をアルゴンガス雰囲
気下で昇温速度40℃/minで2000℃まで昇温し、そのまま
2000℃に15分保持して黒鉛化繊維を得た。得られた黒鉛
化繊維の引張強度および引張弾性率を測定したところ、
糸径10μm、強度215kgf/mm2、弾性率47tf/mm2であっ
た。Comparative Example 3 The infusible fiber used in Example 1 was heated at a rate of 5 ° C./min from 300 ° C. to 400 ° C. at a rate of 5 ° C./min in a mixed gas atmosphere of 50% by volume of steam and 50% by volume of nitrogen gas, and left at 400 ° C. for 1 hour. Holding was performed to obtain a treated fiber. Next, the treated fiber is heated up to 2000 ° C at a heating rate of 40 ° C / min in an argon gas atmosphere, and
It was kept at 2000 ° C. for 15 minutes to obtain a graphitized fiber. When the tensile strength and tensile modulus of the obtained graphitized fiber were measured,
The yarn diameter was 10 μm, the strength was 215 kgf / mm 2 , and the elastic modulus was 47 tf / mm 2 .
実施例1〜3および比較例1〜3で明らかなように、
炭化繊維、不融化繊維いずれの場合においても本発明の
効果により黒鉛化繊維の引張強度が改善される。As is clear in Examples 1 to 3 and Comparative Examples 1 to 3,
In both cases of the carbonized fiber and the infusible fiber, the effect of the present invention improves the tensile strength of the graphitized fiber.
実施例4 石油重油留分の流動接触触媒分解装置(FCC装置)か
ら得られる分解残渣油(デカントオイル)を、大気圧下
での沸点範囲を360℃から520℃に蒸留した油を原料に、
窒素ガスを吹き込みながら圧力0.5kg/cm2、温度450℃で
45分間熱分解重合反応をさせた後、10mmHgの減圧下、温
度460℃で20分間低沸点分を取り除きメソフェーズピッ
チを得た。Example 4 Cracking residue oil (decant oil) obtained from a fluid catalytic cracking unit (FCC unit) of a petroleum heavy oil fraction was distilled from oil having a boiling point range from 360 ° C. to 520 ° C. under atmospheric pressure as a raw material.
At a pressure of 0.5 kg / cm 2 and a temperature of 450 ° C while blowing nitrogen gas
After a thermal decomposition polymerization reaction for 45 minutes, a low boiling point component was removed at a temperature of 460 ° C. under a reduced pressure of 10 mmHg for 20 minutes to obtain a mesophase pitch.
このピッチは、軟化点が320℃、トルエン不溶解分が8
2重量%、キノリン不溶解分が35重量%、メソフェーズ
含有量が100%であった。このメソフェーズピッチを温
度360℃粘度300ポイズで精密濾過網を用いてピッチ中の
不融異物を除去した。This pitch has a softening point of 320 ° C and a toluene insoluble content of 8
2% by weight, quinoline insoluble content was 35% by weight, and mesophase content was 100%. The insoluble foreign matter in the pitch was removed from the mesophase pitch at a temperature of 360 ° C. and a viscosity of 300 poise by using a fine filtration network.
このピッチを用いて従来公知の方法で、キャピラリー
径0.14mm、ノズルホール数200のノズルパックを有する
紡糸機を用いて、メソフェーズピッチの粘度800ポイズ
で糸径13μmのピッチ繊維を得た。Using this pitch, a pitch fiber having a mesophase pitch of 800 poise and a yarn diameter of 13 μm was obtained by a conventionally known method using a spinning machine having a nozzle pack with a capillary diameter of 0.14 mm and 200 nozzle holes.
このピッチ繊維を空気中で150℃から300℃まで1℃/m
inの昇温速度で昇温し、不融化繊維を得た。この不融化
繊維を窒素ガス雰囲気下、200℃から500℃まで5℃/min
で昇温し、そのまま500℃に30分保持して炭化繊維を得
た。1 ℃ / m from 150 ℃ to 300 ℃ in air
The temperature was raised at a rate of in to obtain infusible fibers. 5 ℃ / min from 200 ℃ to 500 ℃ under nitrogen gas atmosphere
And kept at 500 ° C. for 30 minutes to obtain carbonized fibers.
つぎにこの炭化繊維を水蒸気20体積%と窒素ガス80体
積%の混合ガス雰囲気下の炉内で、840℃で5分処理し
た後、アルゴンガス雰囲気下で昇温速度40℃/minで2000
℃まで昇温し、そのまま2000℃に15分保持して黒鉛化繊
維を得た。得られた黒鉛化繊維の引張強度および引張弾
性率は糸径10μm、強度300kgf/mm2、弾性率41tf/mm2で
あった。Next, this carbonized fiber is treated at 840 ° C. for 5 minutes in a furnace in a mixed gas atmosphere of 20% by volume of steam and 80% by volume of nitrogen gas, and then heated at a rate of 40 ° C./min.
The temperature was raised to 2000 ° C. and kept at 2000 ° C. for 15 minutes to obtain a graphitized fiber. The obtained graphitized fiber had a tensile strength and a tensile modulus of elasticity of 10 μm, a strength of 300 kgf / mm 2 and a modulus of elasticity of 41 tf / mm 2 .
比較例4 実施例4で用いた不融化繊維を、窒素ガス雰囲気下20
0℃から1000℃まで5℃/minで昇温し炭化繊維を得た
後、アルゴンガス雰囲気下で昇温速度40℃/minで2000℃
まで昇温し、そのまま15分保持して黒鉛化繊維を得た。
得られた黒鉛化繊維の引張強度および引張弾性率を測定
したところ、糸径10μm、強度250kgf/mm2、弾性率40tf
/mm2であった。Comparative Example 4 The infusibilized fiber used in Example 4 was treated under a nitrogen gas atmosphere for 20 minutes.
After raising the temperature from 0 ° C to 1000 ° C at 5 ° C / min to obtain carbonized fiber, 2000 ° C at a rate of 40 ° C / min in an argon gas atmosphere
Then, the temperature was maintained for 15 minutes to obtain a graphitized fiber.
When the tensile strength and the tensile elastic modulus of the obtained graphitized fiber were measured, the yarn diameter was 10 μm, the strength was 250 kgf / mm 2 , and the elastic modulus was 40 tf.
It was / mm 2.
実施例1、4および比較例1、4から明らかなよう
に、出発原料が石炭系ピッチあるいは石油系ピッチにか
かわらず、本発明の効果により黒鉛化繊維の引張強度が
改善される。As is clear from Examples 1 and 4 and Comparative Examples 1 and 4, the tensile strength of the graphitized fiber is improved by the effect of the present invention regardless of whether the starting material is coal-based pitch or petroleum-based pitch.
以上の実施例および比較例から明らかなように、本発
明の方法によって製造された炭素繊維は従来法に比べ優
れた引張強度を有している。As is clear from the above Examples and Comparative Examples, the carbon fibers produced by the method of the present invention have excellent tensile strength as compared with the conventional method.
発明の効果 本発明によれば、ピッチ系炭素繊維にその繊維断面構
造上発生し易い表面欠陥に対して耐性のある、すなわち
破壊靭性の改善を図ることによって、引張強度が改善さ
れた、高性能な炭素繊維を得ることができる。Effect of the Invention According to the present invention, pitch-based carbon fibers are resistant to surface defects that are likely to occur in the cross-sectional structure of the fibers, that is, by improving fracture toughness, improved tensile strength, high performance Carbon fiber can be obtained.
また、本発明法による炭素繊維構造では、炭素繊維製
造後に生じる表面欠陥に対しても強度低下は少なく、高
性能な繊維物性が安定して得られ易い特徴を有すると考
えられる。Further, it is considered that the carbon fiber structure according to the method of the present invention has a feature that the strength is less reduced even with respect to surface defects generated after carbon fiber production, and high-performance fiber properties are easily obtained stably.
第1図は本発明による、水蒸気濃度50体積%と窒素ガス
50体積%の混合ガス雰囲気下における処理温度が850℃
の際の処理時間と2000℃焼成後の引張強度の関係を示す
図である。FIG. 1 shows a water vapor concentration of 50% by volume and nitrogen gas according to the present invention.
850 ° C processing temperature in 50% by volume mixed gas atmosphere
FIG. 4 is a diagram showing the relationship between the processing time and the tensile strength after firing at 2000 ° C.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 砂子 洋文 神奈川県川崎市中原区井田1618番地 新 日本製鐵株式會社第1技術研究所内 (72)発明者 富岡 紀夫 神奈川県川崎市中原区井田1618番地 新 日本製鐵株式會社第1技術研究所内 (58)調査した分野(Int.Cl.6,DB名) D01F 9/00 - 9/32──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Hirofumi Sunago 1618 Ida, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside the 1st Technical Research Laboratory of Nippon Steel Corporation (72) Inventor Norio Tomioka 1618 Ida, Nakahara-ku, Kawasaki-shi, Kanagawa Nippon Steel Corporation 1st Technical Research Institute (58) Field surveyed (Int. Cl. 6 , DB name) D01F 9/00-9/32
Claims (1)
維を酸化性ガス雰囲気下で不融化した不融化繊維、ある
いは前記の不融化繊維を不活性ガス雰囲気下で炭化した
炭化繊維を、水蒸気雰囲気下もしくは5体積%以上の水
蒸気を含む混合ガス雰囲気下で、450℃以上1000℃以
下、10秒以上4時間以下で処理した後、1300℃以上で炭
素化、黒鉛化することを特徴とするピッチ系炭素繊維の
製造方法。An infusibilized fiber obtained by infusing pitch fibers obtained from a mesophase pitch in an oxidizing gas atmosphere, or a carbonized fiber obtained by carbonizing the infusibilized fiber in an inert gas atmosphere, in a steam atmosphere or in a steam atmosphere. Pitch-based carbon fiber characterized in that it is treated in a mixed gas atmosphere containing at least volume% of steam at 450 ° C to 1000 ° C for 10 seconds to 4 hours, and then carbonized and graphitized at 1300 ° C or more. Manufacturing method.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP30328089A JP2766530B2 (en) | 1989-11-24 | 1989-11-24 | Method for producing pitch-based carbon fiber |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP30328089A JP2766530B2 (en) | 1989-11-24 | 1989-11-24 | Method for producing pitch-based carbon fiber |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH03167316A JPH03167316A (en) | 1991-07-19 |
JP2766530B2 true JP2766530B2 (en) | 1998-06-18 |
Family
ID=17919064
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP30328089A Expired - Lifetime JP2766530B2 (en) | 1989-11-24 | 1989-11-24 | Method for producing pitch-based carbon fiber |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP2766530B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007297762A (en) * | 2006-04-04 | 2007-11-15 | Mitsubishi Rayon Co Ltd | Method for producing carbon fiber |
-
1989
- 1989-11-24 JP JP30328089A patent/JP2766530B2/en not_active Expired - Lifetime
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007297762A (en) * | 2006-04-04 | 2007-11-15 | Mitsubishi Rayon Co Ltd | Method for producing carbon fiber |
Also Published As
Publication number | Publication date |
---|---|
JPH03167316A (en) | 1991-07-19 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4115527A (en) | Production of carbon fibers having high anisotropy | |
US5968435A (en) | Process for manufacturing pitch-type carbon fiber | |
US4574077A (en) | Process for producing pitch based graphite fibers | |
JPH0314624A (en) | Production of carbon yarn | |
US4356158A (en) | Process for producing carbon fibers | |
JP2766530B2 (en) | Method for producing pitch-based carbon fiber | |
JP2766521B2 (en) | Method for producing pitch-based carbon fiber | |
JP2849156B2 (en) | Method for producing hollow carbon fiber | |
JPH0516475B2 (en) | ||
JPH0718057B2 (en) | Pitch-based fiber manufacturing method | |
JPS60104528A (en) | Preparation of carbon fiber | |
JPH06146120A (en) | Pitch-based carbon fiber having high strength and high elastic modulus and its production | |
JPS6278220A (en) | Production of ribbon-like carbon fiber | |
JPS59168123A (en) | Preparation of pitch carbon yarn | |
US4490239A (en) | Pitch for carbon fibers | |
JPS60181313A (en) | Manufacture of pitch fiber | |
JP2678384B2 (en) | Pitch for carbon fiber and method of manufacturing carbon fiber using the same | |
JP3125062B2 (en) | Carbon fiber production method | |
JPS61215692A (en) | Mesophase pitch suitable for high-performance carbon fiber and its production | |
JP4601875B2 (en) | Carbon fiber manufacturing method | |
JP3164704B2 (en) | Method for producing pitch-based high compressive strength carbon fiber | |
JPH0144750B2 (en) | ||
JPH0144751B2 (en) | ||
JPH0796725B2 (en) | Pitch-based carbon fiber manufacturing method | |
JP3024320B2 (en) | Method for producing high strand strength carbon fiber |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
S111 | Request for change of ownership or part of ownership |
Free format text: JAPANESE INTERMEDIATE CODE: R313111 |
|
R360 | Written notification for declining of transfer of rights |
Free format text: JAPANESE INTERMEDIATE CODE: R360 |
|
R371 | Transfer withdrawn |
Free format text: JAPANESE INTERMEDIATE CODE: R371 |
|
S111 | Request for change of ownership or part of ownership |
Free format text: JAPANESE INTERMEDIATE CODE: R313111 |
|
R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090403 Year of fee payment: 11 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090403 Year of fee payment: 11 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100403 Year of fee payment: 12 |
|
EXPY | Cancellation because of completion of term | ||
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100403 Year of fee payment: 12 |