JP2004331686A

JP2004331686A - Aqueous abrasive machining fluid

Info

Publication number: JP2004331686A
Application number: JP2003124946A
Authority: JP
Inventors: Shigenori Fukuoka; 重範福岡
Original assignee: Kyoeisha Chemical Co Ltd
Current assignee: Kyoeisha Chemical Co Ltd
Priority date: 2003-04-30
Filing date: 2003-04-30
Publication date: 2004-11-25
Anticipated expiration: 2023-04-30
Also published as: JP4363890B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-miscible abrasive machining fluid which can stably and uniformly disperse abrasive grains, has good abrading power and penetration, and excels in the efficiency of cooling frictional heat. <P>SOLUTION: The water-miscible abrasive machining fluid is obtained by dispersing diamond abrasive grains into a mixed aqueous solution of an aqueous solution containing an alkylene glycol and a ≤10C lower carboxylic acid salt and an aqueous solution containing a phosphoric acid salt. As the alkylene glycol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol or a polyethylene glycol having a molecular weight of 100-1,000 is suitable. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、超硬金属、ステンレス、チタン等の金属類、炭化珪素、窒化ガリウム等のセラミックス類、サファイヤ、結晶化ガラス等の電子材料等の各種の硬質材料を研磨する際に使用される水系研磨加工液に関するものである。
【０００２】
【従来の技術】
硬質材料の研磨は、研磨砥粒が分散している研磨加工液をかけながら研磨パッドを材料の研磨面に定加重で押し付けることで行われる。番手の小さな（粒子の粗い）研磨砥粒から始めて段階的に番手を大きくする。最近ではダイヤモンド砥粒の粒子が小さく揃ったものを得られるようになったため、研磨の初期段階からダイヤモンド砥粒を使って平坦度の高い研磨面を効率的に仕上げることができるようになっている。研磨加工液は水系と非水系（油性系）があるが、取扱いが簡単なため主に水系が使用されている。
【０００３】
かかる研磨に使用される研磨加工液は、研磨砥粒を均一に分散して研磨面に潤沢に送り込む、研磨定盤と研磨面の間を潤滑にする、研磨定盤と研磨面の摩擦熱を冷却する、というような役割を負っている。従来の研磨加工液として、例えば特許文献１に記載されているようなアルキレングリコールモノアルキルエーテル、高級脂肪酸その塩を含むものが示されている。特許文献２には、グリコール化合物、高級脂肪酸金属塩を含む研磨加工液が記載されている。
【０００４】
【特許文献１】特開平８−２８７４５６号公報
【特許文献２】特開２０００−１４１２１０号公報
【０００５】
【発明が解決しようとする課題】
本件出願の発明者による追試験のためアルキレングリコールと高級脂肪酸塩の研磨加工液でステンレスのような硬質材料を研磨したところ、研磨面の仕上がりの表面粗さは良かったが、研磨加工中の滑りが良すぎて研磨レートが上がらないという結果がでている。
【０００６】
本発明は、特許文献１や特許文献２に示された従来の研磨加工液を改良するためになされたもので、研磨砥粒を安定して均一に分散でき、研磨能、浸透性がよく、摩擦熱の冷却効率が優れた研磨加工液を提供するものである。
【０００７】
【課題を解決するための手段】
前記の目的を達成するためになされた本発明の水系研磨加工液は、アルキレングリコールおよび炭素数１０以下の低級カルボン酸塩を含有する水溶液と、リン酸塩を含有する水溶液との混合水溶液にダイヤモンド砥粒を分散させている。
【０００８】
アルキレングリコールとしては、例えばエチレングリコール、ジエチレングリコール、プロピレングリコール、ジプロピレングリコール、分子量１００〜１０００のポリエチレングリコールが使用できる。
【０００９】
アルキレングリコールの混合水溶液中の割合は、１〜９０％が好ましく、２０〜４０％であればさらに好ましい。１％未満ではダイヤモンド砥粒が沈降する傾向がみられ、研磨面の表面粗さが悪くなる。９０％以上であると粘性が高くなりすぎ、他の添加物の溶解性も悪くなってしまう。
【００１０】
炭素数１０以下の低級カルボン酸塩の酸の具体例は、カプリル酸、ペラルゴン酸、カプリン酸等のモノカルボン酸、蓚酸、マロン酸、コハク酸、アジピン酸、アゼライン酸、セバシン酸等のジカルボン酸、乳酸、グルコン酸、リンゴ酸、酒石酸、クエン酸等のオキシカルボン酸、フタル酸、トリメシン酸、トリメリット酸等の芳香族カルボン酸、ニトリロトリ酢酸、エチレンジアミンテトラ酢酸等がある。炭素数１０以下の低級カルボン酸塩の塩基としてはナトリウム、カリウム、アンモニウム、トリエタノールアミン等の水溶性アミンが使用できる。これらの酸と塩基は任意に組み合わされる。
【００１１】
炭素数１０以下の低級カルボン酸塩の水系研磨加工液中の割合は０．０１〜５％が好ましい。０．０１％以下では研磨能が低く加工レートが上がらない。５％以上加えてもさほど研磨能が上がらないので無駄になる。
【００１２】
また水系研磨加工液に分散させるダイヤモンド砥粒の種類は、単結晶、多結晶どちらでもよく、天然又は合成のダイヤモンドを使用できる。粒径は、研磨能を向上させ加工レートを上げるため、０．５μｍ以上が好ましく、さらに好ましくは１μｍ以上が良い。大きいほど研磨能が上がるが、研磨面の表面粗さが大きくなってしまうため、通常は１０μｍ程度までの粒子径が使われる。
【００１３】
本発明の水系研磨加工液には、上記成分の他に防錆剤、界面活性剤、防腐剤を含有することもできる。
【００１４】
【発明の実施の形態】
本発明の水系研磨加工液は、以下のように調製される。アルキレングリコールを適当量の純水に溶かし、そこに炭素数１０以下の低級カルボン酸塩を溶かして水溶液を準備する。その水溶液にリン酸塩の純水溶液を加え、さらに防錆剤等の他の添加成分を加えてから純水で濃度調整をして混合水溶液を得る。この混合水溶液にダイヤモンド砥粒を加えミキサーで高速攪拌するとダイヤモンド砥粒が分散浮遊状態となり、水系研磨加工液が得られる。
【００１５】
尚、混合水溶液を得るために全量の純水に全成分を同時に加えることも、溶解が潤沢に進めば問題ない。またダイヤモンド砥粒を分散させるため、必要なら超音波分散機やビーズミルを併用してもよい。
【００１６】
本発明の水系研磨加工液は、図１に示すような研磨機で、硬質材料のワーク１を研磨する際に使用される。ワーク１は、荷重回転軸１４に繋がるセラミック板１２にワックスによって複数枚貼り付けられる。荷重回転軸１４は図示しない回転駆動源に繋がっている。数本の円形溝１１が削条された回転定盤１０は、受盥（不図示）を伴って回転駆動源に繋がっている。水系研磨加工液は、タンク１５に貯蔵され、配管パイプによりバルブ１６を経て給液ノズル１７から回転定盤１０の上に向けて噴霧される。回転定盤１０の受盥の下方ドレインにつながる配管パイプからポンプ１８でタンク１５に吸い上げられる。このようにして水系研磨加工液は、タンク１５→バルブ１６→ワーク１と研磨パッド１３の摺接面（研磨面）→ドレイン（不図示）→ポンプ１８→タンク１５と循環してゆく。
【００１７】
研磨加工のときには、回転定盤１０が回転し、セラミック板１２が回転すると、ワーク１が荷重を受けながら回転定盤１０に摺接する。このとき水系研磨加工液は、溝１１に溜まりながら回転定盤１０の上を濡らしているため、ワーク１と回転定盤１０との摺接面で研磨機能を果たす。
【００１８】
【実施例】
以下、本発明を適用する実施例と本発明を適用外の比較例の水系研磨加工液を試作し研磨加工に供した例を説明する。
【００１９】
表１に示す配合によって実施例１、比較例１、実施例２、比較例２、実施例３、実施例４、表２に示す配合によって比較例３、比較例４、比較例５、比較例６、比較例７、比較例８、実施例５の水系研磨加工液を、上記の手順により調製した。
【００２０】
【表１】

【００２１】
【表２】

【００２２】
各実施例および比較例で試作した水系研磨加工液を使い、図１に示す研磨加工機で以下のとおり研磨加工をした。予めフェーシングした錫下定盤を用い硬質材料のワーク用テストピースとしてＳＵＳ３０４（５ｍｍ×５ｍｍ）をセラミックス上定盤にワックスで貼り付けた。水系研磨加工液を３０秒毎に３ミリリットル噴霧しながら、セラミックス板に３６．５ｋｇの荷重をかけ６０ｒｐｍで６０分研磨した。
【００２３】
研磨の終了したテストピースの研磨面を表面粗さ計（東京精密社製サーフコム５９０Ａ）で測定した。テストピースの研磨前後の重量差から加工レートを算出した。表面粗さＲａ（ｎｍ）、加工レートｍｇ／ｍｇのデータを、表１および表２に併せて記載してある。表１および表２から明らかなように本発明の水系研磨加工液を使った研磨面の表面粗さの値は小さく、加工レート、すなわち同一定条件下における研磨による減量が大きいことが分かる。
【００２４】
【発明の効果】
以上、詳細に説明したように、本発明の水系研磨加工液は研磨砥粒を安定して均一に分散でき、研磨能、浸透性がよく、摩擦熱の冷却効率が優れている。そのため本発明の水系研磨加工液を使うことによって、研磨加工面の表面粗さが小さいものとなる。また研磨加工による減量が大きく短時間で研磨できるようになる。すなわち、本発明の水系研磨加工液は、研磨精度の向上と研磨加工の時間短縮に資するところが大である。
【図面の簡単な説明】
【図１】研磨加工機による研磨加工の状態を示す図である。
【符号の説明】
１はワーク、１０は定盤、１１は溝、１２はセラミック板、１４は荷重回転軸、１５はタンク、１６はバルブ、１７は給液ノズル、１８はポンプである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an aqueous material used for polishing various hard materials such as metals such as hard metal, stainless steel and titanium, ceramics such as silicon carbide and gallium nitride, and electronic materials such as sapphire and crystallized glass. The present invention relates to a polishing liquid.
[0002]
[Prior art]
Polishing of a hard material is performed by pressing a polishing pad with a constant load on a polishing surface of a material while applying a polishing liquid in which polishing abrasive grains are dispersed. Start with small (grainy) abrasive grains and gradually increase the count. In recent years, it has become possible to obtain small and uniform diamond abrasive grains, so that highly polished surfaces with high flatness can be efficiently finished using diamond abrasive grains from the initial stage of polishing. . There are aqueous and non-aqueous (oil-based) polishing liquids, but mainly water-based liquids are used because they are easy to handle.
[0003]
The polishing liquid used for such polishing is to uniformly disperse the abrasive grains and send it abundantly to the polishing surface, lubricate between the polishing platen and the polishing surface, and reduce the frictional heat between the polishing platen and the polishing surface. It has a role of cooling. As a conventional polishing liquid, for example, a liquid containing an alkylene glycol monoalkyl ether and a higher fatty acid salt thereof as described in Patent Document 1 is disclosed. Patent Document 2 describes a polishing liquid containing a glycol compound and a higher fatty acid metal salt.
[0004]
[Patent Document 1] Japanese Patent Application Laid-Open No. 8-287456 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-141210
[Problems to be solved by the invention]
When a hard material such as stainless steel was polished with a polishing solution of an alkylene glycol and a higher fatty acid salt for a follow-up test by the inventor of the present application, the finished surface roughness of the polished surface was good, but slip during polishing was performed. Is too good and the polishing rate does not increase.
[0006]
The present invention has been made in order to improve the conventional polishing solution shown in Patent Document 1 and Patent Document 2, can stably and uniformly disperse the abrasive grains, good polishing ability, good permeability, An object of the present invention is to provide a polishing liquid having an excellent frictional heat cooling efficiency.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the aqueous polishing solution of the present invention comprises a mixed aqueous solution of an aqueous solution containing an alkylene glycol and a lower carboxylate having 10 or less carbon atoms and an aqueous solution containing a phosphate. Abrasive grains are dispersed.
[0008]
As the alkylene glycol, for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, and polyethylene glycol having a molecular weight of 100 to 1,000 can be used.
[0009]
The ratio of the alkylene glycol in the mixed aqueous solution is preferably 1 to 90%, more preferably 20 to 40%. If it is less than 1%, the diamond abrasive grains tend to settle, and the surface roughness of the polished surface becomes poor. If it is 90% or more, the viscosity becomes too high, and the solubility of other additives becomes poor.
[0010]
Specific examples of lower carboxylate acids having 10 or less carbon atoms include monocarboxylic acids such as caprylic acid, pelargonic acid and capric acid, and dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, adipic acid, azelaic acid and sebacic acid. Oxycarboxylic acids such as lactic acid, gluconic acid, malic acid, tartaric acid, and citric acid; aromatic carboxylic acids such as phthalic acid, trimesic acid, and trimellitic acid; nitrilotriacetic acid; and ethylenediaminetetraacetic acid. As the base of the lower carboxylate having 10 or less carbon atoms, water-soluble amines such as sodium, potassium, ammonium and triethanolamine can be used. These acids and bases are optionally combined.
[0011]
The proportion of the lower carboxylate having 10 or less carbon atoms in the aqueous polishing solution is preferably 0.01 to 5%. If it is less than 0.01%, the polishing ability is low and the processing rate does not increase. Even if it is added in an amount of 5% or more, the polishing ability does not increase so much that it is useless.
[0012]
The type of diamond abrasive grains dispersed in the aqueous polishing solution may be either single crystal or polycrystal, and natural or synthetic diamond can be used. The particle size is preferably 0.5 μm or more, more preferably 1 μm or more, in order to improve the polishing ability and increase the processing rate. The polishing ability increases as the size increases, but the surface roughness of the polished surface increases. Therefore, a particle diameter of about 10 μm is usually used.
[0013]
The water-based polishing liquid of the present invention may contain a rust inhibitor, a surfactant, and a preservative in addition to the above components.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
The aqueous polishing solution of the present invention is prepared as follows. An alkylene glycol is dissolved in an appropriate amount of pure water, and a lower carboxylate having 10 or less carbon atoms is dissolved therein to prepare an aqueous solution. A pure aqueous solution of a phosphate is added to the aqueous solution, and other components such as a rust inhibitor are further added, and the concentration is adjusted with pure water to obtain a mixed aqueous solution. When diamond abrasive grains are added to this mixed aqueous solution and the mixture is stirred at high speed by a mixer, the diamond abrasive grains are in a dispersed and floating state, and a water-based polishing liquid is obtained.
[0015]
It should be noted that there is no problem if all components are simultaneously added to all amounts of pure water in order to obtain a mixed aqueous solution, provided that the dissolution proceeds abundantly. If necessary, an ultrasonic dispersing machine or a bead mill may be used to disperse the diamond abrasive grains.
[0016]
The water-based polishing liquid of the present invention is used when polishing a hard material work 1 with a polishing machine as shown in FIG. A plurality of workpieces 1 are attached to the ceramic plate 12 connected to the load rotating shaft 14 by wax. The load rotation shaft 14 is connected to a rotation drive source (not shown). The rotary platen 10 having several circular grooves 11 cut is connected to a rotary drive source with a receiving tub (not shown). The water-based polishing liquid is stored in a tank 15 and sprayed from a liquid supply nozzle 17 onto the rotary platen 10 through a valve 16 by a pipe. The pump 18 pumps up the tank 15 from a piping pipe connected to a drain below the receiving tub of the rotary platen 10. In this way, the aqueous polishing liquid circulates from the tank 15 → the valve 16 → the sliding surface (polishing surface) of the work 1 and the polishing pad 13 → the drain (not shown) → the pump 18 → the tank 15.
[0017]
At the time of polishing, when the rotating platen 10 rotates and the ceramic plate 12 rotates, the work 1 comes into sliding contact with the rotating platen 10 while receiving a load. At this time, the water-based polishing liquid wets the surface of the rotary platen 10 while remaining in the grooves 11, and thus performs a polishing function on the sliding contact surface between the work 1 and the rotary platen 10.
[0018]
【Example】
Hereinafter, an example in which a water-based polishing liquid of an example to which the present invention is applied and a comparative example to which the present invention is not applied is trial-produced and subjected to polishing is described.
[0019]
Example 1, Comparative Example 1, Example 2, Comparative Example 2, Example 3, Example 4 according to the formulation shown in Table 1, Comparative Example 3, Comparative Example 4, Comparative Example 5, Comparative Example according to the formulation shown in Table 2. The aqueous polishing liquids of 6, Comparative Example 7, Comparative Example 8, and Example 5 were prepared according to the above procedure.
[0020]
[Table 1]

[0021]
[Table 2]

[0022]
Polishing was carried out as follows using a polishing machine shown in FIG. 1 using the aqueous polishing liquids experimentally produced in the respective examples and comparative examples. SUS304 (5 mm × 5 mm) as a test piece for work of a hard material was attached to a ceramic upper surface plate with wax using a tin lower surface plate pre-facing. The ceramic plate was polished at 60 rpm for 60 minutes while applying a load of 36.5 kg while spraying 3 ml of the aqueous polishing solution every 30 seconds.
[0023]
The polished surface of the polished test piece was measured with a surface roughness meter (Surfcom 590A manufactured by Tokyo Seimitsu Co., Ltd.). The processing rate was calculated from the difference in weight between before and after polishing of the test piece. The data of the surface roughness Ra (nm) and the processing rate mg / mg are also shown in Tables 1 and 2. As is clear from Tables 1 and 2, the value of the surface roughness of the polished surface using the aqueous polishing liquid of the present invention is small, and the processing rate, that is, the weight loss by polishing under the same constant condition is large.
[0024]
【The invention's effect】
As described above in detail, the water-based polishing liquid of the present invention can stably and uniformly disperse abrasive grains, has good polishing ability and permeability, and has excellent cooling efficiency of frictional heat. Therefore, by using the aqueous polishing solution of the present invention, the surface roughness of the polished surface is reduced. In addition, the loss due to the polishing process is large and polishing can be performed in a short time. In other words, the water-based polishing liquid of the present invention greatly contributes to improvement of polishing accuracy and reduction of polishing time.
[Brief description of the drawings]
FIG. 1 is a diagram showing a state of polishing by a polishing machine.
[Explanation of symbols]
1 is a work, 10 is a platen, 11 is a groove, 12 is a ceramic plate, 14 is a load rotating shaft, 15 is a tank, 16 is a valve, 17 is a liquid supply nozzle, and 18 is a pump.

Claims

An aqueous polishing solution in which diamond abrasive grains are dispersed in a mixed aqueous solution of an aqueous solution containing an alkylene glycol and a lower carboxylate having 10 or less carbon atoms and an aqueous solution containing a phosphate.

The aqueous polishing liquid according to claim 1, wherein the alkylene glycol is at least one glycol selected from ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, and polyethylene glycol.

The lower carboxylate is caprylic acid, pelargonic acid, monocarboxylic acid such as capric acid, oxalic acid, malonic acid, succinic acid, adipic acid, azelaic acid, dicarboxylic acid such as sebacic acid, lactic acid, gluconic acid, malic acid, It is composed of at least one acid selected from tartaric acid, citric acid, phthalic acid, trimesic acid, trimellitic acid, nitrilotriacetic acid, and ethylenediaminetetraacetic acid, and at least one base selected from sodium, potassium, ammonium, and triethanolamine. The aqueous polishing liquid according to claim 1, wherein: