JP2004337986A - Cylindrical resin grindstone and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical resin grindstone which is high in water resistance, and fit for grinding of a soft workpiece, and to provide a method of manufacturing the same. <P>SOLUTION: A grindstone piece 16 of the cylindrical resin grindstone contains a resin binder formed of a phenolic resin, and therefore by virtue of the high water resistance, the life of the grindstone is not degraded even in grinding work in which a large quantity of grinding water is used. The texture of the phenolic resin for connecting abrasives together is formed of a three-dimensional mesh structure having a number of minute communicating pores 26, and therefore its porosity is as high as about 70 %, so that an apparent elasticity is set to about 3.3 (GPa) which is drastically degraded compared with the elasticity of an original phenolic resin. Therefore similarly to the case of a grindstone piece in which PVA is employed as a binder, a grinding surface of the present grindstone is elastically deformed conforming to a surface of the workpiece to a slight extent. Thus even if the workpiece is of a soft material, formation of scratches etc. on the surface is advantageously suppressed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００７７】

【００７８】
上記の評価結果に示されるように、ビトリファイド砥石を用いた比較例１では、高い研削力を有するものの面粗度が極めて悪く、スクラッチも生じている。これは、ビトリファイド砥石のヤング率や砥石強度が高いことに起因するものと考えられる。また、砥石の目詰りも頻繁に見られた。したがって、ビトリファイド砥石は硬すぎて十分な面精度を得られないことが判る。
【００７９】
また、ＰＶＡ砥石を用いた比較例２では、比較的良好な面粗度が得られ且つスクラッチも生じない反面、砥石磨耗が著しく大きく、且つ磨耗が安定せずときとして異常磨耗が見られた。これはＰＶＡの欠点である耐水性の不足が原因であるものと考えられる。
【００８０】
また、レジノイド砥石を用いた比較例３では、ＰＶＡ砥石を用いた比較例２よりも高い研削力を有するが、ビトリファイド砥石を用いた比較例１ほどでは無いもののスクラッチが生じる問題がある。砥石の水はけ向上の目的で切込みパターン（図６（ｄ）参照）が設けられているので、これにより生じた砥石片のエッジが銅板表面に当たることがスクラッチの主因と考えられる。
【００８１】
これらに対して、多孔質のレジノイド砥石を用いた実験例の円筒状樹脂砥石１０によれば、上記評価結果の範囲内において最も優れた面粗度が得られると共に、ＰＶＡ砥石を用いた比較例２に比較して寿命の点でも安定していることが判る。すなわち、熱硬化性樹脂、特にフェノール樹脂で結合剤が構成されることから、ＰＶＡ砥石のような研磨水による砥石劣化が生じないので、寿命が安定するのである。従って、プリント配線基板１００のような大量生産され且つ高品質が要求される軟らかい被研削材の研磨加工に好適である。プリント配線基板のような軟削材で且つ表面にうねりが存在し、砥石がその表面になじむ必要のある研磨加工には円筒状樹脂砥石１０のような弾性体ロール構造が好ましいのであるが、加工品質には、そのような構造に加えて、研削に直接関与する砥石片１６の構成がその研削性能に著しく影響するものと考えられる。
【００８２】
上述したように、本実施例によれば、砥石片１６の樹脂結合剤がフェノール樹脂で構成されることから、その高い耐水性に基づき、多量の研削水を用いるような研削加工においても、砥石寿命が低下することがない。このとき、砥粒を相互に結合させるフェノール樹脂組織が微小連通気孔２６を無数に有する三次元網目構造を備えることからその気孔率が７０％程度と高いため、見掛けの弾性率が３．３（ＧＰａ）程度とフェノール樹脂本来のものに比べて著しく低下させられる。そのため、ＰＶＡが結合剤として用いられた砥石片の場合と同様に、研削面が被研削材表面に倣って僅かに弾性変形させられることにより、軟らかい被研削材の場合にも、その表面にスクラッチ等が形成されることが好適に抑制される。しかも、微小連通気孔２６を有する三次元網目構造の樹脂組織によって保持された砥粒２２は、比較的弱い力で脱落するので、被研削材の表面を傷つけにくく、且つ良好な切れ味が長期間に亘って維持される。したがって、耐水性が高く且つ軟らかい被研削材の研削に好適に用い得る円筒状樹脂砥石１０が得られる。
【００８３】
したがって、プリント配線基板１００のような軟削材の平坦化のための研磨加工に用いられても、その表面にスクラッチ等を形成することなく、高い研削力を得ることのできる利点がある。
【００８４】
また、本実施例によれば、砥石片１６は、微小連通気孔２６よりも十分に大径の独立気孔２８を多数有するため、一層高い気孔率を有し、且つ研削加工中に発生した切り粉がその独立気孔内にも捕捉されるため、一層高い研削性が得られる利点がある。
【００８５】
また、本実施例によれば、硬化工程３では、流し込み工程２において型４０内に流し込まれた流動性混合物４２中の水に溶解しているフェノール樹脂が三次元的に架橋することにより硬化成形体となって水から相分離するとともに、その硬化させられたフェノール樹脂が結合剤２４として砥粒２２を相互に結合するが、上記流動性混合物４２は、混合攪拌工程１において砥粒２２およびアルカリ性フェノール樹脂水溶液が均一に混合させられているので、硬化成形体には、硬化させられたフェノール樹脂結合剤２４中に砥粒２２および水が均一に分散している。そして、乾燥工程４において、その硬化成形体から水分が除去されて、その部分が微小連通気孔２６となるので、このような過程を経て製造された砥石片１６は、フェノール樹脂結合剤２４が三次元網目構造を有することにより、砥粒２２よりも小径の微小連通気孔２６が無数に構成された構造を有する。そのため、前述したような特性を備えた円筒状樹脂砥石１０が得られるのである。
【００８６】
また、本実施例によれば、混合攪拌工程１においては流動性混合物４２の内部に多数の気泡が巻き込まれるが、界面活性剤が混合されている場合には、その起泡作用および整泡作用によって均一な気泡が発生し且つその状態が長時間に亘って維持されるため、流し込み工程２において型４０内に流し込まれ、更に硬化工程３において硬化させられる過程においても、その創成された気泡の殆どが維持される。そのため、フェノール樹脂が硬化させられ、更に水分が除去される過程を経て製造された砥石片１６には、微小連通気孔２６に加えて、その微小連通気孔２６よりも十分に大径の多数の独立気孔２８が上記気泡に由来して備えられる。そのため、砥石片１６は２種類の気孔形態を有し且つ高い気孔率を有するので、研削加工中に発生した切り粉が独立した大径気孔２８内にも捕捉されると共に、微小連通気孔２６により砥石としての強度を十分に保ちながら砥粒２２を保持する保持力が弱くなりすぎることがなく、研削過程で結合剤２４が抵抗なく適度に磨耗していくことが可能となるので、高い研削性が得られる。
【００８７】
また、相分離調整剤が混合される場合には、攪拌工程１において、相分離調整剤によって微細且つ均一なミセル状の相分離形態の大きさが調整されるので、所望の大きさの微細且つ均一な微小連通気孔２６が形成される利点がある。すなわち、相分離調整剤は、硬化工程３においてフェノール樹脂が硬化させられるとき、そのフェノール樹脂からブリードアウトする水を保持することにより、硬化時の収縮を抑制して微小連通気孔２６の径寸法を制御する。これにより、所望の大きさの微小連通気孔２６を有し或いは所望の高い気孔率の砥石片１６が得られる。
【００８８】
本実施例においては、乾燥工程４を経て前記硬化成形体から生成された多孔質砥石４４が砥石シート３６に分割された後、その表面から複数本の切込みを所定の深さ寸法で形成することによりその表面を多数の砥石片１６に相当する多数の矩形凸部４６に分割する切込み工程６と、その砥石シート３６をその裏面においてゴムシート３８に貼り付けるゴムシート接着工程７と、切込みに沿って砥石シート３６を多数の砥石片１６に分割する分割工程８と、その砥石シート３６を弾性体層１４の外周面に貼り付けることにより、多数の砥石片１６を固着する砥石シート接着工程Ｒ２とを、含む工程によって円筒状樹脂砥石１０が製造されることから、多数の砥石片１６を容易に芯１２（厳密には弾性体層１４）の外周面に固着することができる。
【００８９】
また、本実施例によれば、フェノール樹脂水溶液はアルカリ性水溶液であり、硬化剤はラクトン系エステル硬化剤であることから、そのラクトン系エステル硬化剤により、流動性混合物中のフェノール樹脂が常温で迅速に硬化させられる利点がある。
【００９０】
また、本実施例では界面活性剤としてアニオン性界面活性剤を用いていることから、そのアニオン性界面活性剤の高い起泡作用により一層気孔率の高い砥石が得られる利点がある。
【００９１】
以上、本発明の一実施例を図面に基づいて説明したが、本発明は上記実施例とは別の態様においても実施できる。
【００９２】
たとえば、前述の実施例では、結合剤２４を構成する熱硬化性樹脂としてアルカリ性フェノール樹脂が用いられていたが、その他のフェノール樹脂も同様に用いられ得る。
【００９３】
また、実施例においては、砥粒２２として＃４００程度の炭化珪素が用いられていたが、砥粒の種類や粒度は用途に応じて適宜選択されるものである。
【００９４】
また、実施例においては、熱硬化性樹脂の三次元網目構造に基づく微小連通気孔２６に加えて混合・攪拌時に巻き込まれた空気に起因する独立気孔２８が形成されていたが、少なくとも微小連通気孔２６が備えられることによって高気孔率の多孔質に構成されていれば、本発明の効果を享受し得る。したがって、混合・攪拌工程１において、気泡が生成するような攪拌形態は必須では無く、また、界面活性剤も必須ではない。
【００９５】
また、実施例においては、相分離調整剤が混合されることによって微小連通気孔２６の大きさが制御されていたが、その大きさのばらつきが許容範囲内に留まるならば、相分離調整剤は混合しなくとも差し支えない。
【００９６】
また、実施例においては、砥石シート３６をその裏面にゴムシート３８を貼り付けた後に割ることによって多数の砥石片１６が一体的に備えられた砥石シート３６を製造し、これを貼り付けることで円筒状部材の表面に多数の砥石片１６を容易に固着していたが、個々に分割された砥石片１６を円筒状部材の外周面に貼り付けても差し支えない。その場合は、ゴムシート３８は用いられなくとも良い。
【００９７】
また、実施例においては、弾性体層１４が多孔質弾性体層１８および緻密質弾性体層２０から構成されていたが、積層構造等するか否かや、如何なる特性を備えた材料で弾性体層１４を構成するかについては、円筒状樹脂砥石１０の用途に応じて適宜選択されるものであり、実施例の構成に限定されない。
【００９８】
以上に説明したものはあくまでも本発明の一実施例であり、本発明はその主旨を逸脱しない範囲において種々変更が加えられ得るものである。
【図面の簡単な説明】
【図１】本発明の円筒状樹脂砥石の全体を示す斜視図である。
【図２】図１の円筒状樹脂砥石を構成する砥石片の表面を拡大して示す図である。
【図３】図１の円筒状樹脂砥石の製造工程を示す工程図である。
【図４】（ａ）〜（ｃ）は、図３の製造工程の要部段階における実施状態を説明するための図である。
【図５】図１の砥石片の製造工程を示す工程図である。
【図６】（ａ）〜（ｅ）は、図５の製造工程の要部段階における実施状態を説明するための図である。
【符号の説明】
１０：円筒状樹脂砥石
１４：弾性体層
１６：砥石片
２２：砥粒
２４：フェノール樹脂結合剤
２６：微小連通気孔
２８：独立気孔[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cylindrical resin grindstone having a large number of grindstone pieces fixed to an outer peripheral surface of a cylindrical member, and more particularly to a cylindrical resin grindstone suitable for polishing a surface of a printed wiring board and a method of manufacturing the same.
[0002]
[Prior art]
For example, when a printed wiring board is manufactured using a so-called build-up method or the like, in an intermediate step, a surface of a semi-finished product of the board is polished and flattened. For example, when a resin is buried in the through-hole, swelling occurs on both surfaces of the semi-finished product, and when an interlayer insulating layer is formed, gentle unevenness occurs on the surface. Therefore, if an insulating layer or a conductor layer is further laminated while these are generated, a short circuit or disconnection of the conductor wiring may occur. Therefore, a flattening process for removing these convex portions is performed.
[0003]
Conventionally, a flattening process of the above-described semi-finished substrate has been performed using, for example, a polishing belt, a nonwoven fabric roll, a nonwoven fabric buff, a cylindrical grindstone (also referred to as a grindstone roll or a cylindrical grindstone). As the wiring board is further multi-layered, the board constituent materials such as the board itself and the resin for filling the through holes tend to become harder. Therefore, a cylindrical grindstone is considered to be preferable for the purpose of leveling a substrate requiring a relatively high grinding force and removing the resin for filling the surface with holes.
[0004]
The above-mentioned cylindrical grindstone has, for example, a large number of grindstone pieces fixed to the outer peripheral surface of a cylindrical member via an elastic body (that is, a low elastic modulus material) (for example, see Patent Document 1). According to such a cylindrical grindstone, the grinding force is less likely to be reduced due to the abrasion and falling off of the abrasive grains as compared with the polishing belt, so that uniform grinding and flattening are easy. In addition, compared to the case of using a nonwoven fabric roll, a nonwoven fabric buff, etc., even when the grinding pressure is increased, the polished surface (that is, the envelope surface at the tip of the nonwoven fabric fiber) is less likely to be deformed according to the substrate surface shape. A high grinding force can be obtained, and the substrate surface can be further flattened. Moreover, since the grindstone pieces fixed to the elastic body are slightly deformed following the substrate surface, scratches on the substrate surface are less likely to occur as compared to a case where the grindstone pieces are supported by a support having a high elastic modulus. There is an advantage that a smooth surface can be obtained.
[0005]
[Patent Document 1]
JP 2001-315064 A
[0006]
[Problems to be solved by the invention]
By the way, the scratch on the substrate surface is likely to occur even when the elasticity of the grindstone piece is high. Therefore, in Patent Literature 1, for example, by using PVA (polyvinyl alcohol) as a binder, the grindstone pieces are configured to have a low elastic modulus of about 1 to 3 (GPa), for example, by a creep test. . In addition, in the grinding of a soft material such as a printed wiring board, it is required that the sharpness is good, no clogging occurs, and that no abrasive grains remain on the surface of the material to be ground. The cylindrical grindstone using the grindstone pieces also satisfies such conditions. However, since PVA is easily dissolved in water, a grinding wheel piece using this as a binder has low water resistance, and the grinding wheel life is significantly shortened in a grinding process using a large amount of grinding water such as substrate surface polishing. There's a problem.
[0007]
On the other hand, a resinoid grindstone using a thermosetting resin such as an epoxy resin or a phenol resin as a binder has high water resistance because it is difficult to dissolve in water. However, since the resinoid grindstone has a high Young's modulus of, for example, about 10 to 12 (GPa), when it is used as a grindstone piece of a cylindrical grindstone, there is an inconvenience that scratches occur as described above. Incidentally, the vitrified grindstone has a higher Young's modulus, for example, about 30 to 35 (GPa), and is more unsuitable as a constituent material of a grindstone piece constituting a cylindrical grindstone.
[0008]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cylindrical resin grindstone having high water resistance and which can be suitably used for grinding a soft material to be ground, and a manufacturing method thereof. It is in.
[0009]
[First means for solving the problem]
The gist of the first invention for solving the above-mentioned problem is that a large number of grinding stone pieces in which abrasive grains are combined with a resin binder are fixed to an outer peripheral surface of a cylindrical member via an elastic layer. (A) a porous resin grindstone in which the abrasive grains are bonded by a thermosetting resin structure having a three-dimensional network structure having a myriad of minute continuous air holes having a smaller diameter than the abrasive grains; In that the grindstone pieces are configured.
[0010]
[Effect of the first invention]
In this case, since the resin binder of the grindstone piece is made of a thermosetting resin, the life of the grindstone is reduced even in a grinding process using a large amount of grinding water based on its high water resistance. There is no. At this time, since the thermosetting resin structure for bonding the abrasive grains to each other has a three-dimensional network structure having a myriad of minute interconnected pores, its porosity is high, so the apparent elastic modulus is the original of the thermosetting resin. Is significantly reduced as compared with Therefore, as in the case of a grinding stone piece in which PVA is used as a binder, the ground surface is slightly elastically deformed following the surface of the material to be ground, so that even in the case of a soft material to be ground, a scratch is formed on the surface. And the like are preferably suppressed. In addition, since the abrasive grains held by the resin structure of the three-dimensional network structure having the minute interconnected pores fall off with a relatively weak force, it is difficult to damage the surface of the material to be ground, and good sharpness is obtained over a long period of time. Will be maintained. Therefore, a cylindrical resin grindstone having high water resistance and suitable for use in grinding soft materials to be ground is obtained.
[0011]
That is, as described in WO 01/85394 filed by the applicant of the present invention and internationally published, according to a porous resinoid grindstone using a thermosetting resin, particularly a phenol resin as a binder, for example, Since the phenolic resin binder has a three-dimensional network structure, a large number of minute continuous air holes having a smaller diameter than the abrasive grains are formed, so that it is easy to obtain protrusions of the abrasive grains on the grinding surface, so high grinding performance is obtained. There are benefits to be gained. In addition to this, the present inventors have found that the apparent elastic modulus of the grindstone decreases with increasing porosity, and studied the applicability as a grindstone piece constituting a cylindrical resin grindstone. Even when a soft material to be ground such as a printed wiring board is ground using a curable resin as a binder, a favorable result is obtained in that scratches are hardly generated. The present invention has been made based on such findings.
[0012]
[Other aspects of the first invention]
Here, preferably, the grindstone pieces have a large number of independent pores having a diameter sufficiently larger than the minute continuous ventilation holes. In this way, since the grinding wheel pieces have a large number of independent pores having a diameter sufficiently larger than the minute continuous pores, they have a higher porosity, and chips generated during the grinding process are also trapped in the independent pores. Therefore, according to the cylindrical resin grindstone to which a large number of such grindstone pieces are fixed, high grindability can be obtained.
[0013]
Preferably, the thermosetting resin is a phenol resin. In this way, the phenolic resin has a relatively high strength, so even if the overall elastic modulus is lowered by adjusting the amount and diameter of the grindstone structure, that is, the pores, the cylindrical resin having a sufficiently high strength is used. A whetstone is obtained.
[0014]
[Second means for solving the problem]
Further, the gist of the second invention for achieving the above object is the method for producing a cylindrical resin grindstone of the first invention, wherein (a) abrasive grains, a thermosetting resin aqueous solution, and a curing agent Mixing and stirring to obtain a fluid mixture, (b) pouring the fluid mixture into a predetermined mold, and (c) mixing the fluid mixture in the predetermined mold. A curing step of curing; (d) a drying step of drying the cured molded article obtained by curing in the curing step to remove moisture from the cured molded article; and (e) the mixing stirring step or the drying step. And a fixing step of fixing a large number of grindstone pieces obtained by the step including the step of fixing to the outer peripheral surface of the cylindrical member via an elastic layer.
[0015]
[Effect of the second invention]
In this way, in the curing step, the thermosetting resin dissolved in the water in the fluid mixture poured into the predetermined mold in the pouring step is three-dimensionally crosslinked to form a cured molded article. And the hardened thermosetting resin binds the abrasive grains to each other as a binder, but the fluid mixture forms a uniform mixture of the abrasive grains and the aqueous thermosetting resin solution in the mixing and stirring step. In the cured molded article, the abrasive grains and water are uniformly dispersed in the cured thermosetting resin binder. Then, in the drying step, moisture is removed from the cured molded body, and the portion becomes a fine continuous air hole. Therefore, the grindstone piece manufactured through such a process is a thermosetting resin binder having a three-dimensional network. By having a structure, it has a structure in which micro communicating air holes having a smaller diameter than the abrasive grains are formed innumerably. Therefore, the cylindrical resin grindstone of the first invention having the above-described characteristics can be obtained.
[0016]
[Another aspect of the second invention]
Here, preferably, the mixing and stirring step is performed by stirring a fluid mixture obtained by mixing an abrasive, an aqueous solution of a thermosetting resin, a curing agent, and a surfactant, so that the abrasive and the aqueous solution of the thermosetting resin are mixed. , A curing agent and a surfactant are uniformly mixed and a large number of gas bubbles are created in the fluid mixture. In this way, in the mixing and stirring step, a large number of air bubbles are trapped inside the fluid mixture, but uniform air bubbles are generated by the foaming action and foam regulating action of the surfactant, and the state is maintained for a long time. Therefore, most of the created bubbles are maintained in the process of being poured into the mold in the pouring step and being cured in the curing step. Therefore, in addition to the micro communication holes, a large number of independent stones having a diameter sufficiently larger than the micro communication holes are added to the grindstone pieces manufactured through a process in which the thermosetting resin is cured and the water is further removed. Pores are provided from the bubbles. In addition, in the curing process, the water solubility of the resin is reduced due to the polymerization of the resin, and solid-liquid phase separation occurs. However, due to the action of the surfactant, fine and uniform micelles (in the surfactant solution) are formed. (Surface-active molecules generated at a certain concentration or more), and then the micelle solvent is removed to form fine and uniform voids. As a result, a cylindrical resin grindstone is obtained in which a grindstone piece having a large number of fine and uniformly distributed fine pores and a large number of uniformly distributed independent pores is fixed to the outer peripheral surface. Since the grindstone pieces thus obtained have two types of pore forms and a high porosity, chips generated during the grinding process are also trapped in the independent large-diameter pores. At the same time, the holding force for holding the abrasive grains while maintaining the strength as a grindstone by the minute continuous ventilation holes does not become too weak, and the binder can be appropriately worn without resistance in the grinding process. , High grindability can be obtained.
[0017]
In the case where the surfactant is mixed as described above, more preferably, the mixing and stirring step is to mix a phase separation modifier together. In this manner, in the stirring step, the size of the fine and uniform micellar phase separation form is adjusted by using the phase separation modifier, so that fine and uniform fine interconnected pores having a desired size are formed. Is done.
[0018]
Preferably, the phase separation regulator is a water-soluble polymer compound having a hydroxy group. In this way, fine and uniform fine continuous ventilation holes having a desired size can be more easily formed. Examples of the water-soluble polymer compound having a hydroxy group include polyvinyl alcohol, carboxymethyl cellulose, and alginic acid.
[0019]
Preferably, the thermosetting resin aqueous solution is an alkaline aqueous solution, and the curing agent is an organic ester curing agent. In this case, there is an advantage that the thermosetting resin in the fluid mixture can be rapidly cured at a relatively low temperature of about room temperature by the organic ester curing agent.
[0020]
Also, preferably, the thermosetting resin aqueous solution is a phenol resin aqueous solution. In this way, the phenolic resin has a relatively high strength, so even if the overall elastic modulus is lowered by adjusting the amount and diameter of the grindstone structure, that is, the pores, the cylindrical resin having a sufficiently high strength is used. A whetstone is obtained.
[0021]
As a curing agent used for curing the phenol resin aqueous solution, an organic ester curing agent is suitably used. As the organic ester curing agent, those conventionally used as curing agents for water-soluble phenol resins can be used. For example, methyl formate, ethyl formate, ethyl acetate, ethyl lactate, methyl sebacate, ethylene glycol Carboxylic acid esters derived from mono- or polyhydric alcohols having 1 to 10 carbon atoms such as diacetate, diacetin and triacetin and organic carboxylic acids having 1 to 10 carbon atoms, or γ-butyrolactone, γ-caprolactone, δ Lactones such as valerolactone, δ-caprolactone, β-propiolactone, ε-caprolactone, or ethylene carbonate, propylene carbonate, 4-ethyldioxolone, 4-butyloxolone, 4,4-dimethyldioxolone And cyclic silky such as 4,5-dimethyldioxolone Emissions carbonates (organic carbonates), and the like. Among them, lactones such as γ-butyrolactone, γ-caprolactone, δ-valerolactone, δ-caprolactone, β-propiolactone, and ε-caprolactone are particularly preferably used for the purpose of solving the problems of odor and flammability.
[0022]
For example, as an aqueous alkaline phenol resin solution, the resin has a weight average molecular weight of 500 to 8000, a solid content of 30 to 75 (% by weight), a molar ratio of formaldehyde to phenol of 1.0 to 3.0, and a hydroxylation to phenol. Those having a molar ratio of an alkali metal hydroxide such as sodium or potassium hydroxide of 0.3 to 1.5 can be used.
[0023]
Further, the alkaline phenol resin aqueous solution is, for example, an alkaline phenol resin curable with an organic ester compound, by condensing phenols and aldehydes in the presence of an alkaline catalyst such as potassium hydroxide or sodium hydroxide. It is obtained.
[0024]
The phenols used for obtaining the water-soluble phenol resin include, in addition to phenol, alkylphenols such as cresol, 3,5-xylenol, nonylphenol, p-tert-butylphenol, isopropenylphenol, and phenylphenol. , Resorcinol, catechol, hydroquinone, phloroglysin and the like. In addition, a mixture of a phenolic compound such as cashew nut grain liquid, lignin, and tannin can also be used as phenols. These various phenols may be used alone or in a mixture of two or more.
[0025]
As the aldehydes, formaldehyde, paraformaldehyde, acetaldehyde, furfural, glyoxal and the like are used alone or in combination of two or more. The aldehyde is preferably in a range of 1.0 to 5.0 times, more preferably 1.5 to 3.0 times, the mole of the phenol. If the aldehyde is less than 1.0 times the molar amount of the phenol, sufficient strength is not exhibited, and if it exceeds 5.0 times, the working environment may be deteriorated due to the unreacted aldehyde. Conventionally known silane coupling agents can also be used as other additives in the phenol resin aqueous solution. For example, 3-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and the like are preferable. The silane coupling agent may be added and blended in the aqueous phenol resin solution, or may be blended by directly adding it in the stirring step.
[0026]
As the catalyst used when the phenols and aldehydes are condensed, alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide are used alone or in combination of two or more. Used. The water-soluble phenol resin is obtained by reacting a phenol and an aldehyde in water in the presence of an alkali metal hydroxide under normal pressure. The molar ratio is preferably in the range of 1.0 to 3.0 times, particularly preferably 1.0 to 3.0 times. When the amount of the alkali metal hydroxide is less than 0.7 times the mole of the phenol, the strength and storage stability of the resin are insufficient. On the contrary, when the amount of the alkali metal hydroxide exceeds 5.0 times the mole, the working environment is not preferable.
[0027]
Further, as the surfactant, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant (nonionic surfactant) and the like can be used. Preferably, an anionic surfactant or a nonionic surfactant is used. When an anionic or nonionic surfactant is used, the anionic or nonionic surfactant has a high foaming effect, so that there is an advantage that a grindstone piece having a higher porosity can be obtained. Examples of the anionic surfactant include fatty acid salts such as sodium laurate, calcium stearate, and sodium oleate, sodium lauryl sulfate, triethanolamine lauryl sulfate, ammonium lauryl sulfate, sodium polyoxyethylene lauryl ether sulfate, and polyoxyethylene alkyl phenyl ether. Sulfuric acid ester salts such as sodium sulfate, sodium dodecylbenzenesulfonate, sodium alkyldiphenylether disulfonate, sodium alkylnaphthalenesulfonate, etc., higher alcohol phosphate monoester disodium salt, alkyl phosphate sodium salt, dialkyldithiophosphoric acid A phosphate salt such as zinc can be used.
[0028]
Examples of the cationic surfactant include higher alkylamine salts such as laurylamine chloride, dihydroxyethylstearylamine and lauryltrimethylammonium chloride, formate of triethanolamine monostearate, acetate of stearamidoethyldiethylamine, and 2-heptadecenyl-hydroxy. Ammonium salts such as amine salts of higher fatty acids such as ethylimidazoline, amine salts of higher alkyl halides such as cetylpyridinium chloride, amine salts of higher aliphatic amides such as stearamidomethylpyridinium chloride, and sulfonium salts or phosphonium salts similar thereto Can be used.
[0029]
Examples of the amphoteric surfactant include N-alkyltriglycine, dimethylalkylbetaine, N-alkyloxymethyl-N, N-diethylbetaine, alkylbetaine, N-alkyl-β-aminopropionate, and alkyldi (aminoethyl) glycine. Hydrochloride, N-alkyl taurine salt, aminoethyl imidazoline organic acid salt and the like can be used. Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl naphthyl ether, polyoxyethylene castor oil, polyoxyethylene abiethyl alcohol, polyoxyethylene alkyl thioether, and polyoxyethylene alkyl thioether. Ethylene alkylamide, polyoxyethylene-polyoxypropylene glycol, polyoxyethylene-polyoxypropylene glycol ethylenediamine, polyoxyethylene monofatty acid ester, polyoxyethylene difatty acid ester, polyoxyethylene propylene glycol fatty acid ester, polyoxyethylene Polyoxyethylene type such as sorbitan monofatty acid ester and polyoxyethylene sorbitan trifatty acid ester Surfactant, ethylene glycol monofatty acid ester, propylene glycol monofatty acid ester, diethylene glycol monofatty acid ester, glycerin monofatty acid ester, pentaerythrit fatty acid ester, sorbitan monofatty acid ester, sorbitan sesqui fatty acid ester, sorbitan trifatty acid ester, sucrose fatty acid Polyhydric alcohol type and alkylolamide type surfactants such as esters, fatty acid monoethanolamide, fatty acid monoisopropanolamide and the like, polyoxyethylene alkylamine, N-alkylpropylenediamine, N-alkylpolyethylenepolyamine, N-alkylpolyethylenepolyaminedimethyl Amine surfactants such as sulfates, alkyl biguanides and long chain amine oxides can be used.
[0030]
As nonionic surfactants, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl naphthyl ether, polyoxyethylated castor oil, polyoxyethylene aviniethyl alcohol, polyoxyethylene alkyl thioether, Polyoxyethylene alkylamide, polyoxyethylene-polyoxypropylene glycol, polyoxyethylene-polyoxypropylene glycol ethylenediamine, polyoxyethylene monofatty acid ester, polyoxyethylene sorbitan monofatty acid ester, polyoxyethylene sorbitan trifatty acid ester Oxyethylene type surfactant, ethylene glycol monofatty acid ester, propylene glycol monofatty acid ester, Polyvalents such as ethylene glycol monofatty acid ester, glycerin monofatty acid ester, pentaerythrit fatty acid ester, sorbitan monofatty acid ester, sorbitan sesquifatty acid ester, sorbitan trifatty acid ester, sucrose fatty acid ester, fatty acid monoethanolamide, fatty acid monoisopropanolamide, etc. Amine types such as alcohol type and alkylolamide type surfactants, polyoxyethylene alkylamine, N-alkylpropylenediamine, N-alkylpolyethylenepolyamine, N-alkylpolyethylenepolypolyamine dimethyl sulfate, alkylbiguanide, and long-chain amine oxide Surfactants can be used.
[0031]
The mechanism by which the micro interconnected pores, which are micro pores, are formed finely and uniformly in the thermosetting resin that is the binder of the grindstone pieces constituting the cylindrical resin grindstone of the present invention is, for example, a phenol resin. , Are considered as follows. In other words, in the process of curing the resin, in other words, in the three-dimensional cross-linking reaction of the polymer chain, in the alkaline phenol resin / ester curing agent reaction system, even when the fluidity of the resin is lost (gel point). In addition, the resin phase is solubilized, and the solvent does not bleed out (leak or leach). Then, when the reaction further proceeds, the cohesive force of the molecular chains acts to separate the resin phase and the solvent phase. The solvent phase that bleeds out in the porous resin of the present invention is mainly water, and corresponding to the interface state between the bleed-out resin phase and the solvent phase, micro-pores after curing are generated and the shape and It is believed that the form of dispersion is determined. The interface state in the phase separation process is controlled using the surfactant. Further, a phase separation regulator is used to control the phase separation process. This phase separation modifier can retain water that bleeds out with the curing of the resin, and by this retention effect suppresses volume shrinkage at the stage when the resin is cured, reducing the amount of water retained by the phase separation regulator. It is considered that the pore size can be controlled to a corresponding size. Therefore, according to the present invention, even if there are no air bubbles caused by the inclusion of air due to agitation or the like, or air bubbles are removed by mechanically taken in air using a vacuum stirrer or the like, according to the present invention, the micro communicating vents Can be obtained finely and uniformly in a phenolic resin binder.
[0032]
Preferably, the predetermined mold has a plane dimension corresponding to a plurality of the grinding stone pieces, and the fixing step includes a step of forming a porous body formed from the cured molded body through the drying step. A cutting step in which the surface is divided into sections corresponding to the plurality of whetstone pieces by forming a plurality of cuts from the surface of the flat whetstone with a predetermined depth dimension, and the flat whetstone is formed on its back surface. A grinding stone attaching step of attaching to a predetermined thin plate-like elastic body, and after the cutting step and the attaching step, attaching the thin plate-like elastic body to the outer peripheral surface of the cylindrical member, the plurality of grinding stone pieces on the outer peripheral surface. And a step of attaching an elastic body.
[0033]
[Other aspects of the first and second inventions]
Preferably, the grinding wheel piece has a large porosity having a porosity in the range of 30 to 75 (vol%) and a pore diameter of 50 (μm) or more, and 0.3 to 30 (μm). ) And small pores having the pore diameter of (1). In this manner, a small-diameter communication having a pore having a sufficient volume, a large-diameter pore having a relatively large diameter functioning as a chip pocket, and a relatively small-diameter pore for suitably dropping a thermosetting resin. Pores are provided. More preferably, the large pores have a pore diameter in the range of 0.1 to 2.0 (mm) and the small pores have a pore diameter of about 1 (μm).
[0034]
Preferably, the whetstone piece has a Young's modulus in the range of 1 to 5 (GPa). By doing so, the elastic modulus is kept at a sufficiently small value, so that it is more suitable for grinding a soft workpiece such as a printed wiring board.
[0035]
Preferably, the grinding wheel piece is fixed to the cylindrical member via a polymer resin foam layer covering the outer peripheral surface of the cylindrical member and an elastic layer covering the polymer resin foam layer. It is a thing. As the polymer resin foam layer, those having a relatively low elastic modulus and light weight are preferable, and for example, foamed polyethylene, foamed polyurethane, vinyl acetate foam (that is, sponge-like vinyl acetate) and the like are suitably used.
[0036]
Preferably, a fiber reinforced rubber layer is interposed between the polymer resin foam layer and the elastic layer. That is, a composite elastic body in which a polymer resin foam layer and a fiber reinforced rubber layer are laminated is provided between the outer peripheral surface of the cylindrical member and the elastic layer.
[0037]
Preferably, the cylindrical resin grindstone is used for polishing the surface of a printed wiring board. As described above, since the cylindrical resin grindstone of the present invention has high water resistance and can be suitably used for grinding a soft material to be ground, it is used for flattening an interlayer insulator layer in a process of manufacturing a printed wiring board. In such a case, it can be used for a long period of time while suppressing the occurrence of scratches.
[0038]
The abrasive grains are appropriately selected depending on the use of the cylindrical resin grindstone. Examples of the abrasive grains include general abrasive grains such as silicon carbide and aluminum oxide, and CBN (cubic boron nitride) and diamond. Of superabrasives. The particle size is also appropriately selected according to the application. For example, it is composed of abrasive grains in a range from about # 120 for rough grinding to about # 4000 for finish polishing.
[0039]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0040]
FIG. 1 is a perspective view showing the entirety of a cylindrical resin grindstone 10 according to one embodiment of the present invention. In the figure, a cylindrical resin grindstone 10 is formed by fixing a large number of grindstone pieces 16 to the outer peripheral surface of a core 12 via an elastic layer 14.
[0041]
The core 12 has a cylindrical shape with an outer diameter of about 88 (mm), an inner diameter of about 76.2 (mm), and a length of about 610 (mm), for example. A paper-resin laminate tube, for example, a paper-phenol resin laminate tube, which is formed by impregnating paper as a material and molding by heating and pressing. In the present embodiment, the core 12 corresponds to a cylindrical member.
[0042]
The elastic layer 14 has, for example, an annular porous elastic layer 18 having an inner diameter of about 88 (mm) and an outer diameter of about 130 (mm), and an outer layer provided over its outer peripheral surface. And a dense elastic layer 20 having a diameter of about 135 (mm). The elastic layer 14 is elastically depressed, for example, when the grindstone pieces 16 are pressed in the radial direction of the cylindrical grindstone 10, so that the grindstone 16 follows the unevenness of the surface of the material to be ground such as a printed wiring board. Is provided for slightly elastically deforming. The porous elastic layer 18 is made of, for example, a sponge-like elastic body such as polyethylene foam, and the dense elastic layer 20 is made of, for example, fiber-reinforced rubber.
[0043]
In addition, the above-mentioned many grindstone pieces 16 have substantially uniform dimensions and shapes, each of which has a rectangular shape, for example, a substantially square planar shape having a side of about 10 (mm) and a plane shape of about 10 (mm). Thickness dimension. The plurality of grindstone pieces 16 are arranged along, for example, chord windings inclined at an angle of about 20 °, and are arranged on the entire outer peripheral surface of the cylindrical resin grindstone 10 by grids having a side of 10 (mm). A pattern is formed. A small gap of, for example, about 1.0 to 2.0 (mm) is provided between the grindstone pieces 16, and the grindstone pieces 16 are not in contact with each other. This gap is for facilitating the discharge of chips during grinding.
[0044]
FIG. 2 is an enlarged view showing the surface of the above-mentioned whetstone piece 16. The grindstone piece 16 has a large number of abrasive grains 22 bonded to each other by a phenolic resin binder 24 having a mesh structure. In the grindstone structure, minute communicating holes 26 and independent pores 28 are formed. I have. Note that this mesh structure is a three-dimensional mesh structure that is similarly continuous in the thickness direction of the grindstone pieces 16. The space formed between the meshes of the phenolic resin binder 24 is the minute communication holes 26, and the network structure of the phenolic resin binder 24 is three-dimensionally expanded. Are also three-dimensionally interconnected. In addition, the independent pores 28 are sufficiently larger than the minute interconnected pores 26, and are substantially uniformly dispersed in the tissue independently of each other. Therefore, the grindstone piece 16 has a remarkably high porosity as a phenol resin grindstone of, for example, about 70 (%), and its elastic modulus is 3.3 (GPa) (= 340 (kgf / mm) in Young's modulus. ² )).
[0045]
The cylindrical resin grindstone 10 configured as described above is manufactured, for example, through the steps shown in FIG. Hereinafter, the manufacturing method will be described with reference to FIGS. First, in the composite elastic body fixing step R1, a laminate of the porous elastic layer 18 and the dense elastic layer 20, that is, the composite elastic body 34 is manufactured and fixed to the outer peripheral surface of the core 12.
[0046]
Next, in the grinding wheel sheet bonding step R2, the grinding wheel sheet 36 is bonded to the outer peripheral surface of the composite elastic body 34. The grindstone sheet 36 has, for example, a thin plate shape having a width of about 50 (mm), a length of about 150 (mm), and a thickness of about 10 (mm). A rubber sheet 38 having, for example, a thickness of about 1 (mm) is adhered to one surface of the side (see FIG. 6 described later). Further, the grinding stone sheet 36 is adhered while being wound spirally in a direction in which the longitudinal direction is along the chord winding having the inclination angle of 20 °. The grindstone sheet 36 is provided with, for example, 45 pieces of the grindstone pieces 16 integrally therewith, and is bonded to the outer peripheral surface of the composite elastic body 34 so that an elastic layer is formed on the outer peripheral surface of the core 12. A large number of grinding stone pieces 16 are fixed via the rubber sheet 14 and 14.
[0047]
After the grindstone sheet 36 is adhered to the entire outer peripheral surface as described above, in the outer diameter finishing step R3, the entire diameter is finished to, for example, about 150 (mm) by grinding, and further, in the end face cutting step R4, for example, the shaft is cut. The cylindrical resin grindstone 10 is obtained by cutting both ends in the center direction with a length of about 20 (mm).
[0048]
In the above-described manufacturing process, the grinding wheel sheet 36 in which the plurality of grinding wheel pieces 16 are integrally provided is manufactured through, for example, each process illustrated in FIG. 6 (a) to 6 (e) are diagrams for explaining an implementation state at a main part stage of this manufacturing process. The aqueous phenol resin solution used in the mixing and stirring step 1 is obtained by condensing phenols and aldehydes in water at normal pressure in the presence of an alkaline catalyst such as potassium hydroxide or sodium hydroxide. In such a case, the above alkaline catalyst is further added. The phenol resin contained in the phenol resin aqueous solution thus obtained is water-soluble, and its weight average molecular weight Mw is, for example, in the range of 500 to 8000.
[0049]
Examples of the above-mentioned phenols include, in addition to phenol, alkyl phenols such as cresol, 3,5-xylenol, nonylphenol, p-tert-butylphenol, isopropenylphenol and phenylphenol, and resorcinol, catechol, hydroquinone and phloroglysin. A phenol may be used. In addition, a mixture of phenolic compounds such as cashew nut shell liquid, lignin and tannin can also be used as phenols. These various phenols can be used alone or in combination of two or more. As the aldehydes, for example, formaldehyde, paraformaldehyde, acetaldehyde, furfural, glyoxal and the like are used, and these can be used alone or in combination of two or more. The aldehydes may be in the range of 1.0 to 5 times the moles of the phenols, particularly preferably in the range of 1.0 to 3.0 times, and more preferably in the range of 1.5 to 2.5 times the moles. More preferred. If the aldehyde is less than 1.0 mole of the phenol, sufficient strength is not exhibited after crosslinking, and if the aldehyde exceeds 5.0 mole, the working environment may be deteriorated due to unreacted aldehyde. is there.
[0050]
As the alkaline catalyst, for example, an alkali metal hydroxide such as lithium hydroxide, sodium hydroxide, or potassium hydroxide is used alone or in combination of two or more. The alkaline catalyst is preferably in a range of, for example, 0.01 to 2 times, more preferably in a range of 0.02 to 1.2 times, and more preferably in a range of 0.5 to 1.0 time, per mole of the phenol. preferable. When the amount of the alkaline catalyst is less than 0.01 times the molar amount of the phenol, the production of the resin takes a long time, and it is insufficient. On the contrary, when the amount exceeds 2.0 times the molar amount of the curing agent is required, This is because the working environment is not preferable.
[0051]
The phenol resin aqueous solution is prepared such that the phenol resin component is in the range of, for example, 30 to 75% by mass. A conventionally known silane coupling agent may be added to the phenol resin aqueous solution as another additive in order to improve the adhesiveness of the abrasive grains. As the silane coupling agent, for example, epoxy silane and amino silane are preferable. Further, this silane coupling agent may be added in the mixing and stirring step 1.
[0052]
As the curing agent used in the mixing and stirring step 1 for curing the phenol resin aqueous solution, an organic ester curing agent, an acid curing agent, or the like can be used. As the organic ester curing agent, those conventionally used as a curing agent for an aqueous alkaline phenol resin solution can be used. For example, methyl formate, ethyl formate, ethyl acetate, ethyl lactate, methyl sebacate, methyl ethylene glycol Carboxylic acid esters derived from mono- or polyhydric alcohols having 1 to 10 carbon atoms such as acetate, diacetin, and triacetin and organic carboxylic acids having 1 to 10 carbon atoms, or γ-butyrolactone, γ-caprolactone, δ- Lactones such as valerolactone, δ-caprolactone, β-propiolactone, ε-caprolactone, or ethylene carbonate, propylene carbonate, 4-ethyldioxolone, 4-butyldioxolone, 4,4-dimethyldioxolone , 4,5-dimethyldioxolone and other cyclic Ruki Ren carbonates, and the like. Among them, lactones such as γ-butyrolactone, γ-caprolactone, δ-valerolactone, δ-caprolactone, β-propiolactone, and ε-caprolactone are particularly preferably used for the purpose of solving odor and flammability problems. it can. Examples of the acid curing agent include inorganic acids such as sulfuric acid and phosphoric acid, organic acids such as phenolsulfonic acid, p-toluenesulfonic acid, and xylenesulfonic acid, and mixtures thereof.
[0053]
In the mixing and stirring step 1, the abrasive grains, the phenol resin aqueous solution, and the curing agent are charged into a stirring mixer, and if necessary, a surfactant and a phase separation modifier are also charged into the stirring mixer, Stir and mix for a predetermined time. In FIG. 5, a broken line indicates an optional mixed component that is not essential. When the surfactant and the phase separation modifier are also mixed, the abrasive, the hardener, and the surfactant (or the phase separation modifier) are sequentially or simultaneously mixed with the phenol resin aqueous solution. In this case, the mixing order may be any. However, the curing agent is preferably added at the end of the mixing and stirring step 1 for controlling the reaction, and then stirred for a predetermined time. In addition, the mixing and stirring step 1 only needs to obtain a fluid mixture in which a phenol resin aqueous solution, abrasive grains, a curing agent, and if necessary, a surfactant and a phase separation modifier are mixed. In this mixing and stirring step 1, a water-soluble phenol resin, water, an alkali metal hydroxide, an abrasive, a curing agent, and, if necessary, a surfactant or a phase separation modifier are mixed in an arbitrary order. By doing so, a fluid mixture may be prepared. Further, a resin strength improver such as hexamine, a stabilizer such as adipic dihydrazide (AADH), a viscosity modifier such as Aerosil, and the like may be appropriately mixed.
[0054]
When the surfactant is not mixed in the fluid mixture, the stirring may be any stirring intensity and time sufficient to uniformly disperse the abrasive grains 22 in the aqueous phenol resin solution. Since the agent is mixed to uniformly generate uniform gas bubbles in the fluid mixture, when the surfactant is mixed in the fluid mixture, the abrasive grains 22 are uniformly dispersed, and The stirring intensity and time are set to be sufficient to generate a desired amount of bubbles. The average pore diameter of the closed cells generated here is 50 (μm) or more.
[0055]
As the above-mentioned surfactant, a desired one can be used from the above-described anionic surfactant, cationic surfactant, amphoteric surfactant, nonionic surfactant and the like.
[0056]
Further, as the phase separation regulator which is mixed so that the size of the fine and uniform micellar phase separation form is adjusted, that is, the fine and uniform fine interconnected pores of a desired size are formed. For example, a water-soluble polymer compound having a hydroxyl group such as polyvinyl alcohol, carboxymethyl cellulose, and alginic acid is suitably used.
[0057]
In the subsequent pouring step 2, the mixture was sufficiently mixed and stirred in the mixing and stirring step 1 in the casting mold 40 having an inner surface shape corresponding to the shape of the grinding stone sheet 36 or an inner surface shape sufficiently larger than the shape. The fluid mixture 42 is poured. FIG. 6A shows this stage.
[0058]
In the subsequent curing step 3, by leaving the fluid mixture 42 poured into the mold 40 in the pouring step 2 for a predetermined time, or by heating the fluid mixture poured into the mold to a predetermined temperature, The phenolic resin in the flowable mixture 42 is cured or crosslinked.
[0059]
When the phenolic resin in the fluid mixture 42 is cured, the fluid mixture 42 becomes a cured molded body having the inner shape of the mold 40. At this time, the phenol resin is cured into a three-dimensional network shape, and the cured phenol resin functions as a binder 24 to bind the abrasive grains 22 to each other. The mechanism by which the phenolic resin crosslinks into a three-dimensional network shape is not necessarily clear, but can be considered as follows. Note that the present invention is not restricted by this mechanism.
[0060]
That is, in the process of hardening the phenol resin by adding a hardener, the water-soluble phenol resin dissolved in water first loses its fluidity without being phase-separated from water (gelation). In this state, the resin phase is solubilized and transparent in appearance, and the solvent is not leached. When the three-dimensional cross-linking reaction further proceeds, it is considered that the cohesive force of the molecular chains acts to separate the resin phase (solid phase) and the aqueous phase (solvent phase) into a three-dimensional network. In this state, the appearance becomes opaque, and if the bleed-out (leaching or leaching) solvent is replaced with air, the three-dimensional mesh-shaped fine continuous air holes 26 are formed. The size or volume ratio of the minute interconnected pores 26 changes by changing the ratio of the water-soluble phenol resin to water. The larger the amount of water with respect to the water-soluble phenol resin, the larger the mesh size or volume ratio. . In addition, the solvent phase at this time is mainly water, and by controlling the interface state between the bleed-out resin phase and the solvent phase using a surfactant, the shape of the micro interconnected pores 26 generated microscopically and The mode of dispersion is adjusted. For example, the pore diameter of the minute continuous air holes 26 is made uniform by the surface active action. Furthermore, when the phase separation modifier is mixed for the purpose of controlling the phase separation process, the phase separation modifier retains water that bleeds out due to the curing of the resin. Volume contraction can be suppressed even at the stage where the resin is cured, which contributes to increasing the pore diameter of the minute interconnected pores 26. By changing the ratio of the water-soluble phenolic resin to water, the mixing ratio of the surfactant, and the mixing ratio of the phase separation controlling agent in this manner, the size of the fine communicating holes 26 is reduced to, for example, 30 (μm) or less, preferably Although it can be changed within a range of 5 (μm) or less, the size of the minute continuous air holes 26 needs to be smaller than that of the abrasive grains 22. This is because the phenolic resin binder 24 cannot support the abrasive grains 22 when the fine continuous air holes 26 have a larger diameter than the abrasive grains 22. In addition, the pore size of the fine interconnected pores is made more uniform by the action of the surfactant.
[0061]
In addition, the surfactant has a function of controlling the independent pores 28. That is, since the fluid mixture foamed in the mixing and stirring step 1 contains a surfactant, bubbles are not lost even in the process of pouring and curing, and the foamed state at the end of stirring is maintained. . Therefore, at the time of completion of the curing, a large number of independent pores 28 independent of each other are formed in the cured molded body as shown in FIG. 2, resulting in a porous molded body. Since many pressures are not applied to the fluid mixture and the cured molded product obtained by curing the fluid mixture, the large number of closed pores 28 are formed in the shape of the bubbles generated in the mixing and stirring step 1 as they are. ing. In order to produce a phenolic resin porous grindstone having no independent pores 28, even when a surfactant is not mixed into the fluid mixture, some bubbles are mixed due to mechanical action of stirring. The independent pores 28 need not be intentionally removed unless they adversely affect the grinding performance.
[0062]
In the subsequent drying step 4, the cured molded body is dried to remove moisture in the cured molded body. When moisture is removed from the cured molded body, the water filling the space between the three-dimensional network structures is replaced with air to form an infinite number of minute communication holes 26, which are also made porous. In the drying step 4, the grindstone sheet 36 or the porous grindstone 44 having a plane size sufficiently larger than the grindstone sheet 36 is manufactured. To improve the strength, a heat treatment step is provided, and the grindstone sheet 36 or the porous grindstone 44 is provided. May be further subjected to a heat treatment. FIG. 6B shows an example of the obtained porous grindstone 44.
[0063]
In the subsequent cutting step 5, when the mold 40 having a size sufficiently larger than the grindstone piece 16 is used, the porous grindstone 44 is cut into a plurality of grindstone sheets 36 by being cut. You. FIG. 6C shows this stage.
[0064]
Next, in the cutting process 6, a number of rectangular projections 46 are formed on the grindstone sheet 36 by making cuts in a lattice shape from the front side of the grindstone sheet 36. The interval between cuts is appropriately determined according to the use of the cylindrical resin grindstone 10. FIG. 6D shows this stage.
[0065]
Next, in a rubber sheet bonding step 7, the rubber sheet 38 is bonded to the back surface of the grinding stone sheet 36, and in the dividing step 8, a rectangular convex portion is formed along the groove formed in the cutting processing step 6. By dividing 46, a grindstone sheet 36 in which a large number of grindstone pieces 16 are adhered to a rubber sheet 38 is obtained. The grinding wheel sheet 36 thus manufactured is used in the grinding wheel sheet bonding step R2.
[0066]
(Experimental example)
Next, a specific experimental example of a method of manufacturing the grindstone sheet 36 will be described. The dimensions of the grindstone sheet 36 were 150 × 50 × 10 (mm), and the dimensions of the grindstone pieces 16 were 10 × 10 × 10 (mm).
[0067]
First, in the mixing and stirring step 1, an alkaline phenol resin aqueous solution (HP8300L manufactured by Asahi Organic Materials Co., Ltd. (solid content: 48% by mass, average molecular weight: 2,000)) was 40% by mass, an anionic surfactant was 2% by mass, and abrasive particles were used. Using 45% by mass of silicon carbide (particle size # 400) and 10% by mass of a lactone-based ester curing agent, they were sequentially charged into a mixer in the following order and mixed and stirred. A TK homomixer manufactured by Tokushu Kika Kogyo Co., Ltd. is used for the mixing machine, and the company's edge turbine is used for the stirring blade. The rotation speed of the stirring blade is 500 to 1500 rpm. p. m. And First, the alkaline phenol resin aqueous solution and the surfactant are charged, and the mixture is stirred for 5 minutes to sufficiently generate air bubbles. Subsequently, a predetermined amount of a stabilizer (for example, adipic dihydrazide: AADH) is added. For 1 minute, followed by adding a predetermined amount of a resin strength improver (eg, hexamine) and mixing and stirring for 1 minute, then adding a predetermined amount of a viscosity modifier (eg, Aerosil) and mixing and stirring for 1 minute, Subsequently, abrasive grains were added and mixed and stirred for 4 minutes. Finally, a predetermined amount of the lactone-based ester curing agent was added and mixed and stirred for 1.5 minutes. Thus, a fluid mixture 42 in which bubbles were uniformly dispersed was obtained.
[0068]
In the subsequent pouring step 2, the fluid mixture 42 obtained in the step 1 is placed in a polypropylene container (that is, a mold 40) having a size of, for example, about 350 × 450 × 60 (mm). In the following curing step 3, the flowable mixture poured into the container was left at, for example, 60 (° C.) for 12 hours to obtain a cured molded body. The size of the mold 40 is selected so that 21 thin plates of that size are obtained in a later step, for example, to be processed into a thin plate having a width of 50 x a length of 150 x a thickness of 10 (mm). .
[0069]
In the subsequent drying step 4, the cured molded body obtained in the above curing step 3 is dried at, for example, 60 (° C.) for 48 hours to completely remove water separated from the resin. Next, the temperature of the cured molded body is continuously raised from room temperature or 60 (° C.) so as to become 150 (° C.) after 6 hours in a state of being housed in the cure container, and maintained at 150 (° C.) for 1 to 2 hours. And the mixture was gradually cooled together with the cure container. After returning to room temperature, the compact was taken out of the cure container to obtain a porous grindstone 44 having a porosity of 70 (%). The Young's modulus of this porous grindstone 44 was about 3.3 (GPa).
[0070]
In the subsequent cutting step 5, the porous grindstone 44 is cut into a plurality of grindstone sheets 36 having a size of, for example, about 50 × 150 × 10 (mm). In the cutting process 6, a plurality of cuts are made in the grindstone sheet 36 along the long side and the short side at a pitch of about 10 (mm) both vertically and horizontally. Further, in the rubber sheet bonding step 7, the grindstone sheet 36 is bonded on a rubber sheet 38 having a size of about 50 × 150 × 1 (mm), and in the dividing step 8, it is bonded on the rubber sheet 38. While being cut, this is divided for each grindstone piece 16 along the cut. Then, the grindstone sheet 36 was adhered to the elastic layer 14, and the cylindrical resin grindstone 10 as described above was obtained through an outer diameter finishing step R3 and an end face cutting step R4.
[0071]
(Comparative example)
As Comparative Example 1, a vitrified grindstone in which silicon carbide abrasive grains (particle size # 400) were bonded with borosilicate glass powder was manufactured, cut into a thin plate having the same size as the grindstone sheet 36, and bonded with a rubber sheet 38. In the same manner as in the case of the grindstone sheet 36, it was wound around and bonded to the elastic layer 14 to form a cylindrical grindstone having the same shape as the cylindrical resin grindstone 10. The structure of the vitrified grindstone is about 45% by volume of abrasive grains, 15% by volume of a binder, and about 40% by volume of pores. The Young's modulus of the whetstone is 41 (GPa) (= 4200 (kgf / mm). ² )) Degree.
[0072]
As Comparative Example 2, a PVA grindstone in which silicon carbide abrasive grains (particle size # 400) were bonded with PVA was manufactured, and a cylindrical grindstone was manufactured in the same manner as in the case of the grindstone sheet 36. The structure of this PVA grindstone is about 15% by volume of abrasive grains, 10% by volume of a binder, and about 75% by volume of pores. The Young's modulus of the grindstone is 1.2 (GPa) (= 120 (kgf / mm). ² )) Degree. In addition, this grindstone piece was subjected to a silicon-based water-resistant treatment.
[0073]
As Comparative Example 3, a resinoid grindstone in which silicon carbide abrasive grains (particle size # 400) were bonded with a liquid epoxy resin was manufactured, and a cylindrical grindstone was manufactured in the same manner as in the case of the grindstone sheet 36. This resinoid grindstone was made porous by mixing with a pore-forming agent (for example, vinylidene chloride / acrylonitrile copolymer Expancel manufactured by Chema Nobel). The structure of the resinoid grindstone is about 10% by volume of abrasive grains, about 30% by volume of a binder, and about 60% by volume of pores. The Young's modulus of the grindstone is 8.5 (GPa) (= 870 (kgf / mm). ² )) Degree.
[0074]
Table 2 below shows, using the cylindrical resin grindstone 10 of the above-described experimental example and the cylindrical grindstone of each of the above-mentioned comparative examples, each of which was performed under the grinding conditions shown in Table 1 to compare the grinding test results. I have. Evaluation items are grinding force (evaluated by the amount of cutting (g) after 2000 passes of the copper plate), finished surface accuracy (evaluated by the surface roughness (Rz, unit: μm) of the polished copper plate), whetstone life (amount of whetstone wear) That is, the grinding wheel volume reduction (cm ³ ), The presence or absence of scratches and abrasive grains remaining on the copper plate surface after polishing (observed with a low-magnification stereomicroscope), and the life stability (evaluated by the change in the amount of wear of the grinding wheel every 200 passes). Table 3 shows the change in the amount of wear of the grindstone.
[0075]
[Table 1] Grinding conditions
Testing equipment Uniaxial polishing machine manufactured by Ishii Notation Co., Ltd.
Work copper plate (width 300 x length 450 x thickness 0.1 (mm))
Wheel peripheral speed 840 (m / min) (rotation speed 1800 rpm)
Work feed speed 2 (m / min)
Oscillation 350 (cpm)
Load +1.0 (A)
[0076]

[0077]

[0078]
As shown in the above evaluation results, Comparative Example 1 using the vitrified grindstone has a high grinding force, but has extremely poor surface roughness and scratches. This is considered to be due to the high Young's modulus and high strength of the vitrified grinding wheel. Also, clogging of the whetstone was frequently observed. Therefore, it is understood that the vitrified grindstone is too hard to obtain sufficient surface accuracy.
[0079]
In Comparative Example 2 using a PVA grindstone, relatively good surface roughness was obtained and no scratch was generated, but the wear of the grindstone was remarkably large, and abnormal wear was sometimes seen when the wear was not stable. This is thought to be due to the lack of water resistance, which is a drawback of PVA.
[0080]
Further, Comparative Example 3 using the resinoid grindstone has a higher grinding force than Comparative Example 2 using the PVA grindstone, but has a problem that scratches are generated, though not as much as Comparative Example 1 using the vitrified grindstone. Since a cutting pattern (see FIG. 6D) is provided for the purpose of improving drainage of the grindstone, it is considered that the resulting edge of the grindstone piece hitting the copper plate surface is the main cause of the scratch.
[0081]
On the other hand, according to the cylindrical resin grindstone 10 of the experimental example using the porous resinoid grindstone, the most excellent surface roughness was obtained within the range of the above evaluation results, and the comparative example using the PVA grindstone was used. It can be seen that the life is more stable than that of No. 2. That is, since the binder is composed of a thermosetting resin, particularly a phenol resin, the grinding wheel is not deteriorated by polishing water such as a PVA grinding wheel, so that the life is stabilized. Therefore, it is suitable for polishing a soft material to be ground, such as the printed wiring board 100, which is mass-produced and requires high quality. An elastic roll structure such as a cylindrical resin grindstone 10 is preferable for a polishing process that is a soft cutting material such as a printed wiring board and has a waviness on the surface, and the grindstone needs to adjust to the surface. In terms of quality, in addition to such a structure, the configuration of the grinding wheel piece 16 directly involved in grinding is considered to significantly affect the grinding performance.
[0082]
As described above, according to the present embodiment, since the resin binder of the grindstone pieces 16 is made of a phenol resin, the grindstone can be used even in a grinding process using a large amount of grinding water based on its high water resistance. The life is not shortened. At this time, since the phenol resin structure for bonding the abrasive grains to each other has a three-dimensional network structure having countless minute air holes 26, the porosity is as high as about 70%, and the apparent elastic modulus is 3.3 ( GPa), which is significantly lower than that of the phenol resin. Therefore, as in the case of a grinding stone piece in which PVA is used as a binder, the ground surface is slightly elastically deformed following the surface of the material to be ground, so that even in the case of a soft material to be ground, a scratch is formed on the surface. And the like are preferably suppressed. In addition, since the abrasive grains 22 held by the resin structure having the three-dimensional network structure having the minute continuous air holes 26 fall off with a relatively weak force, it is difficult to damage the surface of the material to be ground, and good sharpness is obtained over a long period of time. Is maintained throughout. Therefore, the cylindrical resin grindstone 10 which has high water resistance and can be suitably used for grinding a soft material to be ground is obtained.
[0083]
Accordingly, even when used for polishing for flattening a soft cutting material such as the printed wiring board 100, there is an advantage that a high grinding force can be obtained without forming a scratch or the like on the surface.
[0084]
Further, according to the present embodiment, since the grindstone pieces 16 have a large number of independent pores 28 having a diameter sufficiently larger than the fine continuous pores 26, they have a higher porosity, and chips generated during the grinding process. Is also trapped in the independent pores, so that there is an advantage that higher grindability can be obtained.
[0085]
Further, according to the present embodiment, in the curing step 3, the phenolic resin dissolved in the water in the fluid mixture 42 poured into the mold 40 in the pouring step 2 is three-dimensionally cross-linked to form a curing mold. The hardened phenolic resin binds the abrasive grains 22 to each other as a binder 24 while being phase-separated from the water, and the fluid mixture 42 forms the abrasive grains 22 and the alkaline Since the phenol resin aqueous solution is uniformly mixed, the abrasive grains 22 and water are uniformly dispersed in the cured phenol resin binder 24 in the cured molded body. Then, in the drying step 4, the moisture is removed from the cured molded body, and the part becomes the minute continuous air holes 26. Thus, the grinding wheel piece 16 manufactured through such a process is manufactured by the phenol resin binder 24 By having the original mesh structure, it has a structure in which minute continuous air holes 26 smaller in diameter than the abrasive grains 22 are formed innumerably. Therefore, the cylindrical resin grindstone 10 having the above-described characteristics can be obtained.
[0086]
Further, according to the present embodiment, in the mixing and stirring step 1, a large number of bubbles are trapped inside the fluid mixture 42, but when a surfactant is mixed, the foaming action and the foam regulating action are performed. As a result, uniform bubbles are generated and the state is maintained for a long time. Therefore, even in the process of being poured into the mold 40 in the pouring step 2 and being cured in the curing step 3, the generated bubbles Most are maintained. Therefore, the grinding wheel piece 16 manufactured through the process of curing the phenol resin and further removing water has a large number of independent diameters sufficiently larger than the minute communication holes 26 in addition to the minute communication holes 26. Pores 28 are provided from the air bubbles. Therefore, since the grinding wheel piece 16 has two types of pore forms and has a high porosity, chips generated during the grinding process are also trapped in the independent large-diameter pores 28, and the fine continuous ventilation holes 26 Since the holding force for holding the abrasive grains 22 while maintaining the strength as a whetstone is not too weak, and the binder 24 can be appropriately worn without resistance during the grinding process, high grindability can be obtained. Is obtained.
[0087]
Further, when the phase separation modifier is mixed, the size of the fine and uniform micellar phase separation form is adjusted by the phase separation modifier in the stirring step 1, so that the desired size of fine and There is an advantage that uniform minute continuous ventilation holes 26 are formed. That is, when the phenolic resin is cured in the curing step 3, the phase separation modifier holds water that bleeds out of the phenolic resin, thereby suppressing shrinkage during curing and reducing the diameter of the micro communication vent 26. Control. As a result, the grindstone pieces 16 having the small continuous air holes 26 of a desired size or having a desired high porosity can be obtained.
[0088]
In this embodiment, after the porous grindstone 44 generated from the cured molded body through the drying step 4 is divided into the grindstone sheets 36, a plurality of cuts are formed at a predetermined depth from the surface thereof. A cutting step 6 of dividing the surface into a number of rectangular projections 46 corresponding to a number of grinding stone pieces 16, a rubber sheet bonding step 7 of attaching the grinding stone sheet 36 to a rubber sheet 38 on the back surface thereof, Dividing step 8 for dividing the grindstone sheet 36 into a large number of grindstone pieces 16, and a grinding stone sheet bonding step R2 for fixing the large number of grindstone pieces 16 by attaching the grindstone sheet 36 to the outer peripheral surface of the elastic layer 14. Since the cylindrical resin grindstone 10 is manufactured by a process including the following, a large number of grindstone pieces 16 can be easily fixed to the outer peripheral surface of the core 12 (strictly speaking, the elastic layer 14).
[0089]
Further, according to this example, the phenol resin aqueous solution is an alkaline aqueous solution, and the curing agent is a lactone-based ester curing agent. Therefore, the lactone-based ester curing agent allows the phenol resin in the fluid mixture to be rapidly cooled at room temperature. Has the advantage of being cured.
[0090]
Further, in this embodiment, since an anionic surfactant is used as the surfactant, there is an advantage that a grindstone having a higher porosity can be obtained by a high foaming action of the anionic surfactant.
[0091]
As mentioned above, although one Example of this invention was described based on drawing, this invention can be implemented also in another aspect from the said Example.
[0092]
For example, in the above-described embodiment, an alkaline phenol resin is used as the thermosetting resin constituting the binder 24, but other phenol resins may be used similarly.
[0093]
Further, in the embodiment, silicon carbide of about # 400 is used as the abrasive grains 22, but the type and the grain size of the abrasive grains are appropriately selected according to the application.
[0094]
In addition, in the embodiment, in addition to the small communicating holes 26 based on the three-dimensional network structure of the thermosetting resin, the independent pores 28 caused by the air entrapped at the time of mixing / stirring are formed. If it is configured to have a high porosity by being provided with 26, the effects of the present invention can be enjoyed. Therefore, in the mixing / stirring step 1, a stirring mode that generates bubbles is not essential, and a surfactant is not essential.
[0095]
In addition, in the embodiment, the size of the fine interconnected pores 26 was controlled by mixing the phase separation adjusting agent. However, if the variation in the size remains within an allowable range, the phase separation adjusting agent is No need to mix.
[0096]
Further, in the embodiment, the grindstone sheet 36 is integrally provided with a large number of grindstone pieces 16 by attaching the rubber sheet 38 to the back surface of the grindstone sheet 36 and then dividing the same. Although a large number of grindstone pieces 16 are easily fixed to the surface of the cylindrical member, the individually divided whetstone pieces 16 may be attached to the outer peripheral surface of the cylindrical member. In that case, the rubber sheet 38 may not be used.
[0097]
In the embodiment, the elastic layer 14 is composed of the porous elastic layer 18 and the dense elastic layer 20. However, the elastic layer 14 is made of a material having any characteristic whether or not it has a laminated structure. Whether to form the layer 14 is appropriately selected according to the use of the cylindrical resin grindstone 10 and is not limited to the configuration of the embodiment.
[0098]
What has been described above is merely an embodiment of the present invention, and the present invention can be variously modified without departing from the gist thereof.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an entire cylindrical resin grindstone of the present invention.
FIG. 2 is an enlarged view showing a surface of a grindstone piece constituting the cylindrical resin grindstone of FIG. 1;
FIG. 3 is a process chart showing a manufacturing process of the cylindrical resin grindstone of FIG. 1;
4 (a) to 4 (c) are views for explaining an implementation state at a main part stage of the manufacturing process of FIG. 3;
FIG. 5 is a process chart showing a manufacturing process of the grindstone piece of FIG. 1;
6 (a) to 6 (e) are views for explaining an implementation state at a main part stage of the manufacturing process of FIG. 5;
[Explanation of symbols]
10: Cylindrical resin whetstone
14: Elastic layer
16: Whetstone pieces
22: abrasive
24: phenolic resin binder
26: Micro continuous vent
28: Independent pore

Claims (7)

A cylindrical resin grindstone in which a large number of grindstone pieces in which abrasive grains are bonded with a resin binder are fixed to the outer peripheral surface of the cylindrical member via an elastic layer,
The plurality of grindstone pieces are composed of a porous resin grindstone whose abrasive grains are bonded by a thermosetting resin structure having a three-dimensional network structure having countless minute communicating pores smaller in diameter than the abrasive grains. A cylindrical resin grindstone characterized by the following. 2. The cylindrical resin grindstone according to claim 1, wherein the grindstone pieces have a large number of independent pores having a diameter sufficiently larger than the minute continuous ventilation holes. 3. The cylindrical resin grindstone according to claim 1, wherein the grindstone pieces have a Young's modulus in a range of 1 to 5 (GPa). The cylindrical resin grindstone according to claim 1, which is used for polishing the surface of a printed wiring board. Abrasive grains, a thermosetting resin aqueous solution, and a mixing and stirring step of uniformly mixing and stirring a curing agent to form a fluid mixture,
A pouring step of pouring the fluid mixture into a predetermined mold,
A curing step of curing the fluid mixture in the predetermined mold,
A drying step of drying the cured molded body obtained by curing in the curing step, and removing moisture from the cured molded body,
A fixing step of fixing a large number of grinding stone pieces obtained by a step including the mixing and stirring step to the drying step on an outer peripheral surface of the cylindrical member via an elastic body layer, Production method. The mixing and stirring step is performed by stirring the fluid mixture obtained by mixing the abrasive grains, the aqueous solution of the thermosetting resin, the curing agent, and the surfactant to form the abrasive grains, the aqueous solution of the thermosetting resin, the curing agent, and the surfactant. 6. The method for producing a cylindrical resin grindstone according to claim 5, wherein the agent is uniformly mixed and a large number of bubbles are created in the fluid mixture. 7. The method for producing a cylindrical resin grindstone according to claim 6, wherein the mixing and stirring step includes mixing a phase separation modifier.

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