JP2004249459A - Glassy binder raw material liquid for vitrified grinding wheel and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glassy binder raw material liquid for a vitrified grinding wheel, and its manufacturing method for obtaining a workpiece surface grade corresponding to an abrasive grain diameter even in a relatively fine grain. <P>SOLUTION: This raw material liquid 1 or 2 is a glassy binder raw material liquid for forming a glassy binder 14 for binding an abrasive grain in a manufacturing process of the vitrified grinding wheel 10, and is composed of an alkoxide composition bonding each of a plurality of constituting elements included in the glassy binder 14 with an alkyl group or an alkoxide polycondensate being the polycondensate of the alkoxide composition, and is formed and deposited from a plurality of elements included in this in the manufacturing process of the vitrified grinding wheel. Since the glassy binder 14 is formed in the further finer particle size than the particle size of the abrasive grain 12 even if the abrasive grain 12 is #3,000 or more (the average particle size 6 μm or less), the vitrified grinding wheel 10 for performing grinding work of the workpiece surface grade corresponding to the abrasive grain diameter can be provided. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a vitrified binder raw material liquid for a vitrified grinding wheel and a method for producing the same, and particularly to a technique using a vitrified binder produced by a solution method as a vitrified bond for binding abrasive grains.

  Generally, as a vitreous binder (vitrified bond) used to bond abrasive grains of a vitrified grindstone to each other, glass powder called a frit is used in a stage of a grindstone raw material. The grindstone raw material is adjusted so that the frit is attached or coated on the outer peripheral surface of the abrasive grains wetted with the primary binder, and after the grindstone raw material is pressure-formed in a predetermined mold, The frit is re-melted in the firing step, so that the abrasive grains are bonded to each other, thereby forming a product. The frit or vitreous binder is intended for bonding between abrasive grains, and when the grain size is larger than 1/2 of the abrasive grains, the vitreous material is exposed or oozes out on the ground surface and the cutting edge of the abrasive grains is removed. It is known that the covering impairs the grinding action and causes grinding burns.

  However, the frit used in practical production methods such as pulverization has a particle size of about 2 to 5 μm, whereas the vitrified whetstone has a particle size number of # 10 (average particle size of 2 mm) according to its use and processing purpose. ) To # 64000 (average particle size 0.3 μm), so that abrasive particles having a fine particle size of, for example, # 1000 or more (average particle size of 15 μm or less), particularly # 3000 or more (average particle size When the abrasive particles have an extremely fine particle diameter (diameter of 6 μm or less), the particle diameter of the glass frit is relatively too large, so that the abrasive particles are not necessarily melted so as to bond between the abrasive particles and are exposed to the ground surface. At present, the surface quality of the workpiece corresponding to the abrasive grain size has not been obtained. For this reason, in such a fine-grained vitrified grinding wheel, a fine vitreous binder for obtaining a surface quality of a workpiece corresponding to the abrasive grain size has been desired.

  The present invention has been made in view of the above circumstances, and an object thereof is to produce a vitrified bond capable of obtaining a workpiece surface quality commensurate with the abrasive grain size even with relatively fine grains. To provide a vitrified binder raw material liquid for a vitrified grinding wheel and a method for producing the same.

  The inventors of the present invention have conducted intensive studies on the background described above, and as a result, have been able to grind an alkoxide solution of four elements of glass, such as Si, Al, B, and Na, required for bonding a vitrified grindstone. When mixed with the particles, cast, and baked, for example, abrasive grains having a fine particle size of # 1000 or more (average particle size of 15 μm or less), particularly ultrafine particles of # 3000 or more (average particle size of 6 μm or less) It has been found that a vitrified binder composed of the oxides of the above four elements, which appropriately binds even abrasive grains having a diameter, is formed to constitute a vitrified grinding wheel. That is, it has been found that when a solution containing an element constituting glass is dried and fired in a state of being mixed with abrasive grains, a vitreous binder composed of the element can be generated in the vitrified grindstone. The vitreous binder thus produced is an abrasive having a fine particle diameter by forming a glass having a fine particle diameter by precipitation in a drying or firing process and dissolving it by firing. Also, it is considered that the glass quality is not exposed or oozes out on the ground surface, and the grinding quality suitable for the abrasive grains having a fine particle diameter can be obtained.

  The present invention has been made based on the above findings, and the gist of the present invention is a vitreous binder raw material liquid for producing a vitreous binder that binds abrasive grains in the process of manufacturing a vitrified grindstone. Wherein the plurality of constituent elements contained in the vitreous binder are each composed of an alkoxide composition bonded to an alkyl group, or an alkoxide condensation polymer which is a condensation polymer thereof.

  According to the vitrified grindstone raw material liquid for vitrified grinding wheels, the vitrified grinding wheel is produced or precipitated in a manufacturing process of the vitrified grindstone from a plurality of elements contained in the vitreous binder raw material liquid, whereby the vitreous bonding is performed. Even if the abrasive particles are fine particles having a size of # 3000 or more, that is, an average particle size of 6 μm or less, the agent is formed into a finer particle size by precipitation than the particle size of the abrasive particles. A vitrified grindstone capable of performing a grinding process of a workpiece surface quality corresponding to the diameter is obtained.

Here, the gist of the method invention for suitably producing the vitreous binder raw material liquid of the first invention is to produce a vitreous binder that binds abrasive grains in the process of manufacturing a vitrified grindstone. A method for producing a vitreous binder raw material liquid, wherein (a) the binder raw material liquid preparation step is represented by a general formula Si (OR ¹ ) ₄ (where R ¹ is an alkyl group having 1 to 4 carbon atoms). And an Al alkoxide represented by the general formula Al (OR ² ) _n · L _m (where R ² is an alkyl group, L is a ligand and n + m = 3) And a B alkoxide or a boron oxide alcohol solution represented by the general formula B (OR ³ ) ₃ (where R ³ is an alkyl group having 1 to 2 carbon atoms) dissolved in a solvent and heated and refluxed in a first heating reflux step. And (b) refluxing in the first heating reflux step The alkoxide solution was, the general formula Na (OR ⁴⁾ (where R ⁴ is an alkyl group having 3-4 carbon atoms) and a second heating to reflux step of further heating reflux was charged with Na alkoxide represented by ( c) a cooling step of cooling the alkoxide solution refluxed in the second heating reflux step, and (d) water and / or acetic acid having a hydrolysis rate of 0 to 100% with respect to the contained metal other than Na diluted with ethanol. And a hydrolysis-condensation polymerization step of sequentially charging and acid-diluting an acid catalyst diluted with ethanol to partially hydrolyze and condensation-polymerize the metal alkoxide in the alkoxide solution to obtain an alkoxide condensation polymer. .

  According to this method invention, there is an advantage that a highly heat-resistant glassy binder composed of oxides of four elements of Si, Al, B, and Na can be obtained.

  Further, the gist of the vitrified grinding wheel using a vitreous binder to bind the abrasive grains according to another aspect of the present invention is that the vitreous binder is contained in a raw material liquid of the vitreous binder. The vitrified grindstone from the plurality of elements to be produced in the manufacturing process.

  According to this configuration, the vitreous binder is generated or precipitated in the manufacturing process of the vitrified grindstone from a plurality of elements contained in the raw material liquid of the vitreous binder. Even fine grains with an average grain size of 6 μm or less are formed into finer grain sizes by precipitation compared to the grain size of the abrasive grains, so grinding the workpiece surface quality commensurate with the abrasive grain size is required. A vitrified grinding wheel that can be performed is obtained.

Here, the vitreous binder produced from the raw material liquid of the vitreous binder has a coefficient of thermal expansion of 3 to 8 × 10 ⁻⁶ / ° C. By doing so, the coefficient of thermal expansion of super-abrasive grains such as CBN and diamond or general abrasive grains such as SiC and Al ₂ O ₃ can be approximated, so that a vitrified grindstone having high heat resistance and thermal shock resistance can be obtained.

Preferably, the raw material liquid of the vitreous binder contains four elements Si, Al, B, and Na. More preferably, the oxide composition of the vitreous bond _{SiO 2 70~90wt%, B 2 O} 3 10~20wt%, Al 2 O 3 1~5wt%, such that the Na ₂ O1~5wt% And four kinds of elements Si, Al and B and an alkali metal and / or an alkaline earth metal. In this manner, a vitreous binder having high heat resistance and high thermal shock, that is, a vitrified bond can be obtained.

  Further, the gist of the invention relating to the production of the vitrified grindstone is a method for producing a vitrified grindstone using a vitreous binder to bind abrasive grains, and (a) a plurality of the vitreous binders. A binder raw material liquid preparing step of preparing a binder raw material liquid containing the elements of (b) and (b) mixing the binder raw material liquid prepared in the binder raw material liquid preparing step and the abrasive grains at a predetermined ratio. A grinding wheel raw material adjusting step of adjusting a fluid grinding wheel raw material, and (c) a molding step of casting the grinding stone raw material adjusted in the grinding stone raw material adjusting step into a molding die to obtain a predetermined molded product; A firing step of firing the molded article formed by the molding step to generate a vitreous binder comprising a plurality of elements contained in the binder raw material liquid and to bond the abrasive grains.

  In this way, the vitreous binder raw material liquid prepared in the binder raw material liquid preparation step is mixed with the fluid grindstone raw material in the grindstone raw material adjustment step, poured into the forming die in the forming step, and then fired. When fired in the process, since the particles are precipitated as particles sufficiently smaller than the abrasive particles and bind the abrasive particles, even if the abrasive particles are fine particles having a size of # 3000 or more, that is, an average particle size of 6 μm or less, Since a finer grain size is formed by precipitation than the grain size of the abrasive grains, a vitrified grindstone capable of performing a grinding process of a workpiece surface quality corresponding to the abrasive grain size is obtained.

  Here, preferably, the vitreous binder raw material liquid is a sol liquid or a precursor thereof, and is converted into a gel in a mold in the molding step. With this configuration, the sol is mixed with the raw material of the grinding stone in the state of the sol and gelled in the molding die, so that the mold can be easily removed from the molding die.

Preferably, the vitreous binder produced from the vitreous binder raw material liquid has a coefficient of thermal expansion of 3 to 8 × 10 ⁻⁶ / ° C. By doing so, the coefficient of thermal expansion of super-abrasive grains such as CBN and diamond or general abrasive grains such as SiC and Al ₂ O ₃ can be approximated, so that a vitrified grindstone having high heat resistance and thermal shock resistance can be obtained.

  Preferably, the vitreous binder raw material liquid is prepared from a mixture of metal alkoxides in which a plurality of constituent elements of the vitreous binder are respectively bonded to alkoxy groups. In this way, the material constituting the vitreous binder can be made into a solution.

  Preferably, the vitreous binder raw material liquid is a metal alkoxide condensation polymer obtained by subjecting a mixture of the metal alkoxide to hydrolysis and condensation polymerization. In this case, the glassy binder raw material liquid is easily converted into a sol, and the amount of KOH (10%) added can be reduced.

Preferably, the binder raw material liquid preparing step comprises: (a) tetraalkyl silicate or silica condensed represented by the general formula Si (OR ¹ ) ₄ (where R ¹ is an alkyl group having 1 to 4 carbon atoms). A polymer, an Al alkoxide represented by the general formula Al (OR ² ) _n · L _m (where R ² is an alkyl group, L is a ligand and n + m = 3), and a general formula B (OR ³ ) ₃ (where R ³ is an alkyl group having 1 to 2 carbon atoms), a solution of a B alkoxide or an alcoholic boron oxide solution in an organic solvent, and heating and refluxing the first heating and refluxing step; Into the alkoxide solution refluxed in the first heating reflux step, an Na alkoxide represented by the general formula Na (OR ⁴ ) (where R ⁴ is an alkyl group having 3 to ⁴ carbon atoms) is added, and further heated to reflux. (C) refluxing by the second heating and refluxing step; A cooling step of cooling the alkoxide solution obtained, and (d) water and / or acetic acid having a hydrolysis rate of 0 to 100% with respect to the contained metal other than Na diluted with ethanol, and an acid catalyst diluted with ethanol. And hydrolyzing and polycondensing the metal alkoxide in the alkoxide solution to partially hydrolyze and polycondensate the alkoxide solution to obtain an alkoxide polycondensate. In this way, there is an advantage that a highly heat-resistant vitreous binder composed of oxides of the four elements of Si, Al, B, and Na can be obtained.

Examples of the alkyl group of the tetraalkyl silicate represented by the above general formula Si (OR ¹ ) ₄ (where R ¹ is an alkyl group having 1 to 4 carbon atoms) include a methyl group, an ethyl group, a propyl group, and a butyl group. . Examples of the silica polycondensate include partial polycondensates such as tetramethyl silicate and tetraethyl silicate, and commercially available ethyl silicate 40 and MS51 (manufactured by Mitsubishi Chemical) can also be used. The alkyl group of the Al alkoxide represented by the general formula Al (OR ² ) _n · L _m (where R ² is an alkyl group, L is a ligand and n + m = 3) is an ethyl group , A propyl group and a butyl group. Examples of the ligand L include acetoketoesters such as ethyl acetoacetate, β-diketones such as acetylacetone and hexafluoroacetylacetone, and alkanolamines such as monoethanolamine and diethanolamine. Examples of the alkyl group of the B alkoxide represented by the above general formula B (OR ³ ) ₃ (where R ³ is an alkyl group having 1 to 2 carbon atoms) include a methyl group and an ethyl group. Examples of the alkyl group of the Na alkoxide represented by the above general formula Na (OR ⁴ ) (where R ⁴ is an alkyl group having 3 to ⁴ carbon atoms) include a propyl group and a butyl group. The water and / or acetic acid is used for controlling a hydrolysis reaction and a polycondensation reaction, and the addition of acetic acid is carried out by utilizing water produced as a by-product of an esterification reaction with an alcohol. The purpose is to make the reaction of the whole system more uniform than to add it itself. Although it is possible to use 100% of the water obtained by the reaction between acetic acid and water, the binding performance of the obtained inorganic polymer compound may deteriorate depending on the combination of materials used. It is desirable to use it effectively. Therefore, the ratio of water / acetic acid is about 20% before and after 1/1. However, an inorganic high molecular compound (a glassy binder raw material liquid) can be produced even if either of them is used at 100%. Further, an inorganic binder (a glassy binder raw material liquid) can be obtained as a metal alkoxide composition obtained without performing hydrolysis (using no water or catalyst). Further, in order to promote the above condensation polymerization reaction, a catalytic acid such as hydrochloric acid, nitric acid, p-toluenesulfonic acid and the like is added. This promotes hydrolysis and condensation polymerization of alkyl silicate and the like in the solution, and promotes condensation polymerization during curing. Further, as the organic solvent, methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol and the like Alcohols and aromatics such as toluene and xylene. Alcohols can be used in any solvent as long as precipitation and gelation do not occur. However, generally, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol and the like having an ether bond contribute to the stabilization of the alkoxide polycondensation product or the alkoxide composition, and are relatively high boiling solvents. This is useful in that rapid volatilization of the solvent at the time of demolding can be prevented. Also, aromatics (preferably toluene) are required as a sodium alkoxide stabilizing solvent.

Preferably, in the binder raw material liquid preparing step, the oxide composition of the vitreous binder is 70 to 90 wt% of SiO _2, 10 to ₂₀ wt% of B ₂ O _{3, 1 to 5} wt% of Al ₂ O ₃ , A binder raw material liquid in which the ratio of the above-mentioned tetraalkyl silicate or silica polycondensate, Al alkoxide, B alkoxide or boron oxide alcohol solution, and Na alkoxide to Na ₂ O _{1 to 5} wt% is prepared. Is what you do. _{Thus, SiO 2 70~90wt%, B 2} O 3 10~20wt%, Al 2 O 3 1~5wt%, Na 2 O1~5wt% high heat resistance vitreous bond consisting obtain There are advantages.

Preferably, in the binder raw material liquid preparation step, 0.03 to 0.3 mol of Al alkoxide, 0.2 to 0.5 mol of B alkoxide and 0 to 0 mol of Na alkoxide are used for 1 mol of the tetraalkyl silicate. Of 0.05 to 0.25 mol in an organic solvent to form a metal alkoxide, and 0 to 8 mol of water and / or acetic acid for hydrolysis are mixed and hydrolyzed to form a 0 to 10 mol of acid serving as a catalyst. The alkoxide polycondensate or alkoxide composition is further added to obtain a binder raw material liquid. _{Thus, SiO 2 70~90wt%, B 2} O 3 10~20wt%, Al 2 O 3 1~5wt%, Na 2 O1~5wt% high heat resistance vitreous bond consisting obtain There are advantages.

  Hereinafter, an application example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an enlarged view showing a configuration of the vitrified grindstone 10. In FIG. 1, a vitrified grindstone 10 is formed by vitrified binder or vitreous binder 14 in which abrasive grains 12 such as superabrasive grains such as CBN and diamond and general abrasive grains such as SiC and Al ₂ O ₃ are melted during firing. By being mutually connected, it is configured to have a large number of continuous ventilation holes 16. FIG. 1 is a cross-sectional view showing a part of the vitrified grinding wheel 10 in an enlarged manner.

  In the vitrified grindstone 10 configured as described above, the cutting surface 20 of the abrasive grain 12 grinds the surface 22 of the work material 18 by bringing the ground surface into sliding contact with the surface of the work material 18. When a part of the abrasive grains 12 is crushed with the grinding, the next cutting edge 20 is regenerated and the grinding performance is continued. The weight ratio of the vitreous binder 14 to the abrasive grains 12 or the whole thereof is determined so that the abrasive grains 12 are required and sufficiently bonded only between the abrasive grains 12. Since the holding power of the abrasive grains 14 is reduced, the abrasive grains 12 fall off together with the crushed abrasive grains 12 so that the next abrasive grains 12 are involved in the grinding. At this time, as the number of the abrasive grains 12 increases, that is, as the grain size decreases, the number of cutting edges involved in grinding decreases, and at the same time, the number of cutting edges increases. Surface quality can be obtained.

  At this time, when the particle size of the abrasive grains 12 is extremely small, for example, the number of the abrasive grains 12 is # 1000 or more, that is, fine particles having an average particle size of 15 μm or less, particularly, # 3000 or more, that is, fine particles having an average particle size of 6 μm or less. Then, in the raw material stage, it becomes difficult in production to make the particle size of the glass frit (glass powder to be the vitreous binder 14) sufficiently smaller than the particle size of the abrasive grains 12, so that in the conventional frit, Since relatively large glass particles are exposed to the grinding surface without melting so as to bond between the abrasive grains, the number of cutting edges is reduced and grinding burns are more likely to occur However, although the inconvenience that the surface quality of the workpiece corresponding to the abrasive grain size is not necessarily obtained cannot be obtained, the vitrified grinding wheel 10 of the present embodiment does not have such a problem. In the manufacturing process, the vitreous binder 14 is generated from the solution mixed in the grindstone raw material, that is, the vitreous binder raw material liquid, and is melted in the firing step. In the formation of the vitreous binder 14, it is considered that fine glass particles are deposited or coated around the abrasive particles 12 in the process of increasing the solution concentration.

  The solution, that is, the vitreous binder raw material liquid is produced, for example, by the process shown in FIG. That is, in FIG. 2, first, a denatured alcohol in which 90% of ethanol and 10% of isopropyl alcohol (IPA) are mixed is prepared as an organic solvent in a predetermined first reaction tank which is a closed container capable of reflux and stirred. (First stirring step P1). Examples of the organic solvent include alcohols such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol, 2-methoxyethanol, 2-ethoxyethanol, and 1-methoxy-2-propanol. And aromatics such as toluene and xylene. Alcohols can be used in any solvent as long as precipitation and gelling do not occur. However, generally, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol and the like having an ether bond contribute to the stabilization of the alkoxide polycondensation product or the alkoxide composition, and are relatively high boiling solvents. Therefore, it is suitably used in that rapid volatilization of the solvent at the time of demolding can be prevented. Further, aromatics (preferably toluene) are useful as a sodium alkoxide stabilizing solvent described later, and are used as necessary.

Next, an alkoxide (metal to which an alkoxyl group is bonded) of a metal element of the metal oxide constituting the vitreous binder 14 is sequentially charged into the first reaction tank and stirred. Vitreous bond 14 of this embodiment, the oxide composition is _{SiO 2 70~90wt%, B 2 O} 3 10~20wt%, Al 2 O 3 1~5wt%, was as Na ₂ O1~5wt% Since the glass is a heat-resistant and heat-shock resistant glass, the alkoxide of a metal element having a composition and a compounding ratio for obtaining such a glass is sequentially dissolved in the organic solvent. That is, a tetraalkyl silicate or silica polycondensate represented by the general formula Si (OR ¹ ) ₄ (where R ¹ is an alkyl group having 1 to 4 carbon atoms) such as ethyl silicate, and trimethyl borate A solution of a B alkoxide or a boron oxide alcohol represented by the general formula B (OR ³ ) ₃ (where R ³ is an alkyl group having 1 to 2 carbon atoms), for example, aluminum-di-sec-butoxy-3oxobutanoic acid Al alkoxide represented by the general formula Al (OR ² ) _n · L _m (where R ² is an alkyl group, L is a ligand, n + m = 3) such as ethyl and a solvent such as ethoxyethanol Are sequentially dissolved in an organic solvent in the first reaction tank (second stirring step P2, third stirring step P3), and heating and reflux are performed in the first reaction tank. It performed 2 hours and 30 minutes approximately a predetermined time (first heating to reflux step P4).

On the other hand, in another second reaction tank, an organic solvent such as a mixture of 2-propanol and toluene is prepared and boiled (boiling step P5), and for example, metallic sodium such as reagent sodium is introduced therein. Is dissolved (dissolution step P6), and then filtered in a filtration step P7 to form a Na alkoxide represented by the general formula Na (OR ⁴ ) (where R ⁴ is an alkyl group having 3 to ⁴ carbon atoms). Is done. After the Na alkoxide thus obtained is further added into the first reaction tank, for example, heating and refluxing at 80 ° C. is performed for a predetermined time of, for example, about 5 hours, and then, in the cooling step P9, 35 It is cooled to room temperature below ℃. The heating and refluxing is for maintaining a bonded state by continuously applying heat to an alkyl group which is easily dissociated from a metal element. Then, in the concentration step P10, the solution cooled in the cooling step P9 is concentrated under heating and reduced pressure at a temperature of 50 ° C. and a pressure of 150 mmHg, so that the organic solvent is volatilized in the solution. The so-called hybrid metal alkoxide mixture containing the alkoxides of the metal elements Si (silicon), Al (aluminium), B (boron), and Na (sodium) contained therein is used as a raw material liquid for the vitreous binder 14 for a vitrified grinding wheel (hereinafter referred to as a raw material). Liquid 1). The raw material liquid 1 is a precursor of the sol liquid, and is concentrated so that the solid content concentration becomes 25 to 40%.

  FIG. 3 shows a process of producing another raw material liquid (hereinafter, referred to as raw material liquid 2) of the vitrified binder 14 for the vitrified grinding wheel. The step shown in FIG. 3 is different in that a fifth stirring step P11 and a second stirring step P12 for performing hydrolysis and polycondensation reactions in two steps in order to slowly liquefy the sol are added. It will be explained mainly. In the fifth stirring step (hydrolysis step) P11, 143.6 g of ion-exchanged water is diluted with 500 g of ethanol and stirred with respect to the alkoxide solution in the first reaction tank cooled to 35 ° C. or lower in the cooling step P9. The hydrolysis reaction is gently started by dropping the mixture under stirring for a predetermined time of, for example, about one hour.

  Next, in a sixth stirring step (hydrolysis condensation polymerization step) P12, an acid catalyst such as p-toluenesulfonic acid was dissolved in 50 g of ethanol in the alkoxide solution in the first reaction tank. The mixture is added dropwise with stirring, and the mixture is further stirred for a predetermined time period of, for example, about 3 hours, thereby performing a hydrolysis reaction and a condensation polymerization reaction. Each metal alkoxide is converted into a hydroxide by the above-mentioned hydrolysis, and each hydroxide is mutually bonded by the above-mentioned condensation polymerization. In the above steps P11 and P12, the amount of ion-exchanged water or water contained in ethanol to be added is such that the hydrolysis reaction proceeds in accordance with the amount thereof, so that the reaction proceeds slowly so as not to cause gelation of the solution. Is set to In the above step P12, the amount of the acid catalyst is set so as not to cause gelation of the solution since the hydrolysis reaction and the polycondensation reaction are promoted in accordance with the amount.

  Then, in the concentration step P10, the solution in the first reaction tank, which has been converted into a sol by being hydrolyzed and polycondensed in the above steps P11 and P12, is heated and concentrated under reduced pressure, whereby the organic solvent in the solution is volatilized. A so-called hybrid metal alkoxide condensation polymer containing alkoxides of the metal elements Si, Al, B, and Na contained in the vitreous binder 14 is used as a raw material liquid of the vitreous binder 14 for a vitrified grinding wheel (hereinafter referred to as a raw material liquid). 2). The raw material liquid 2 is concentrated so that the solid content concentration becomes 25 to 40%.

FIG. 4 shows a vitrified grinding wheel manufacturing process for manufacturing the vitrified grinding wheel 10 using the vitreous binder raw material liquid for a vitrified grinding wheel (raw material liquid 1 or 2) obtained as described above. First, 38 parts by weight of the above-mentioned glassy binder raw material liquid, 27 parts by weight of # 6000 (average particle diameter 2 μm) SiC abrasive grains, and 30 parts by weight of # 6000 (average particle diameter 2 μm) diamond abrasive particles are prescribed. The mixture is put into a mixing vessel and dispersed by mixing with a high-speed stirrer for 1 minute (high-speed stirring step P20). Next, 5 parts by weight of a 10% solution of KOH is further added and mixed quickly (mixing step P21), and the obtained fluid grindstone raw material is poured into a predetermined forming die having an inner diameter of 13 mm and a height of 150 mm, for example. (Pouring step P22). After the gelling of the fluid whetstone raw material accompanying the gelling of the raw material liquid is completed after a predetermined time of about 15 minutes, the molded product is released from the molding die (demolding step P23), and at room temperature for approximately 4 hours. It is dried and the organic solvent is further evaporated (drying step P24). At this stage, a mixture or polycondensation product of the alkoxides of the metal elements Si, Al, B, and Na in the raw material liquid is precipitated around the abrasive grains as fine glass grains sufficiently smaller than the grain size of the abrasive grains. it is conceivable that. Then, the above-mentioned molded article is fired under the firing conditions of holding at 800 ° C. for 1 hour, so that the oxide composition is 70 to 90 wt% of SiO _2, 10 to ₂₀ wt% of B ₂ O _{3, and 1 to 5} wt% of Al ₂ O ₃ . %, Na ₂ O _{1 to 5} wt%, and a vitreous binder 14, which is a heat-resistant and heat-shock resistant glass, is formed between the abrasive grains 12 in a state where the abrasive grains 12 are bonded to each other. can get. In the firing, the temperature was maintained at 150 ° C., 300 ° C., and 500 ° C. for debinding. In a temperature range of 600 ° C. or higher, a nitrogen gas atmosphere was used.

Hereinafter, experimental examples performed by the present inventors will be described. First, an experimental sample 1 is prepared by the process shown in FIG. 4 using the raw material liquid 1 obtained by the process of FIG. 2, and an experiment is performed by the process shown in FIG. 4 by using the raw material liquid 2 obtained by the process of FIG. Sample 2 was prepared. An experimental sample 3 was prepared by using the raw material liquid 2 and setting the particle diameters of the diamond abrasive grains and the SiC abrasive grains to # 10000 and using the process shown in FIG. In all of these experimental samples 1, 2, and 3, the same whetstone composition, that is, 15 parts by volume of diamond abrasive grains, 15 parts by volume of SiC abrasive grains, 10 parts by volume of vitrified bond (vitreous binder 14), The pores 16 have a capacity of 60 and are formed into a pellet shape by being cut to a thickness of 5 mm. As shown in FIG. 5, a certain number of, for example, 36 are provided on one surface of an aluminum base plate 30 having a diameter of 200 mm and a thickness of 5 mm. The individual pieces were adhered, and a polishing test was performed under the following test conditions. 25 parts by volume of a conventional frit (powder) -like vitreous binder which is ground to about 3 μm and contains the same oxide composition as the vitreous binders of the experimental samples 1, 2, and 3; 35 parts by volume of # 6000 diamond abrasive grains, 35 parts by volume of # 6000 SiC abrasive grains, 5 parts by volume of water, and if necessary, using an appropriate adhesive And pressed in a molding die of 13 mmφ at a pressure of about 50 kg / cm ² , baked at 1000 ° C. for 1 hour, and compared pellet shapes similar to experimental samples 1, 2, and 3. Sample 1 was prepared. In this firing, the temperature was maintained at 100 ° C. and 200 ° C. for one hour for debinding, and a nitrogen gas atmosphere was set in a temperature range of 600 ° C. or higher. Further, Comparative Sample 2 was prepared using the same material and process as Comparative Sample 1 except that diamond abrasive grains and SiC abrasive grains of # 10000 were used. These comparative samples 1 and 2 have the same grindstone composition as the experimental samples 1, 2 and 3, that is, 15 parts by volume of diamond abrasive grains, 15 parts by volume of SiC abrasive grains, and a vitrified bond (glassy binder 14). 10 volume parts, the pores 16 are 60 volume parts, formed in the shape of a pellet having a thickness of 5 mm, and a fixed number of, for example, 36 pieces are adhered to one surface of the aluminum base plate 30, and a polishing test is performed under the following test conditions. It was conducted. The reason why the baking temperature of the comparative samples 1 and 2 is set to 1000 ° C. is to sufficiently melt the frit-like vitreous binder used to cause appropriate wetting. The fact that the firing temperature of the experimental samples 1, 2, and 3 was 200 ° C. lower than that means that the vitreous binder in the experimental samples 1, 2, and 3 was formed of the reactive fine particles produced from the solution. Is estimated. This is a major feature when the vitreous binder is generated between the abrasive grains or on the abrasive grain surface by the solution method.

Polishing test conditions Grindstone dimensions: 200mmφ x thickness 40mm (including aluminum base plate 30)
Attaching 36 pieces of 13 mmφ pellet-shaped grindstones to one surface of the base plate Polishing method: Vertical axis surface grinder (single-side polishing)
Wheel speed: 1800m / min
Cutting speed: 10 μm / min
Cutting depth: Total 7μm
Work material and type: 8 inch silicon wafer Work surface before processing: Etching surface Polishing liquid: Water

(Table 1)
Abrasive grain size Binder Grinding resistance Surface roughness Scratches Abrasion stone wear amount # 1 6000 Raw material liquid 1 1.3 kw 6.9nmRa None 2.0μ / Work experimental sample 2 # 6000 Raw material liquid 2 1.3kw 7.1nmRa None 1.5 μ / Work experiment sample 3 # 10000 Raw material liquid 2 1.4 kw 3.8nmRa None 2.0μ / Work comparison sample 1 # 6000 frit 1.9 kw 20.5nmRa Available 3.0μ / Work comparison sample 2 # 10000 frit 2.1 kw 18.4nmRa Available 3.0μ / Work

  Table 1 shows the results of the above experiment. In the grindstones of Experimental Samples 1, 2, and 3, compared to Comparative Samples 1 and 2, the surface roughness of the work material was finer with the same abrasive grains and the same grindstone structure, and a good surface quality with less damage was obtained. Further, in the grindstones of Experimental Samples 1, 2, and 3, the surface roughness is reduced and the surface quality is improved as the abrasive grain size becomes smaller, despite the fact that the abrasive grains are extremely fine grains of # 6000 or more. That is, it is a proof that even the ultrafine abrasive grains 12 of # 6000 or more are securely held one by one by the vitreous binder 14 and that the abrasive grains 12 are preferably sequentially dropped off (does not fall off in a group) even during wear. It can be said that this is a whetstone that can obtain the surface quality of the work material corresponding to the grain size of the material.

  As described above, according to the vitrified whetstone 10 of the present embodiment, the vitreous binder 14 for binding the abrasive grains 12 is formed by using a plurality of elements contained in the vitreous binder raw material liquid 1 or 2 as shown in FIG. In particular, since the vitrified grindstone is generated (precipitated) between the abrasive grains 12 in the manufacturing process of the vitrified grindstone shown in the above, particularly in the drying step P24 and the firing step P25 after the demolding step P23, the abrasive grains are # 1000 or more, especially 3000 or more. In other words, even if the fine particles have an average particle size of 6 μm or less, the fineness of the work surface is suitable for the abrasive particle size after firing because the fine particle size is smaller than that of the abrasive particles 12. The vitrified grindstone 10 capable of performing the grinding process is obtained.

In this embodiment, since the vitreous binder 14 produced from the vitreous binder raw material liquid 1 or 2 has a thermal expansion coefficient of 3 to 8 × 10 ⁻⁶ / ° C., CBN Since the thermal expansion coefficient of a super-abrasive such as diamond or a general abrasive such as SiC or Al ₂ O ₃ can be approximated, a vitrified grindstone 10 having high heat resistance and thermal shock resistance can be obtained.

In this embodiment, the vitreous binder raw material liquid 1 or 2 contains the four elements Si, Al, B, and Na, and more preferably, the oxide of the vitreous binder 14. the composition _{SiO 2 70~90wt%, B 2 O} 3 10~20wt%, Al 2 O 3 1~5wt%, so that the Na ₂ O1~5wt%, 4 kinds of elements Si, Al, B, and Na As a result, the vitreous binder 14 having high heat resistance and high thermal shock resistance, that is, vitrified bond can be obtained.

  Further, the method for manufacturing a vitrified grinding wheel of the present embodiment shown in FIG. 4 includes: (a) a binder material solution forming step of forming the glassy material solution 1 or 2 containing a plurality of elements of the glassy material 14; P1 to P10 (FIG. 2 or FIG. 3), and (b) the binder raw material liquid 1 or 2 prepared in the binder raw material preparation step P1 to P10 and the abrasive grains are mixed at a predetermined ratio and flow. (C) a grinding wheel raw material adjusting process P20 and P21 for adjusting the abrasive wheel raw material, and (c) a molding process P22 in which the grinding wheel raw material adjusted in the grinding wheel raw material adjusting process P20 and P21 is poured into a molding die to form a predetermined molded product. And (d) firing the molded article formed in the forming step P22 to generate a vitreous binder 14 comprising a plurality of elements contained in the binder raw material liquid 1 or 2, thereby bonding the abrasive grains. Firing Since the glassy binder raw material liquid 1 or 2 is mixed with the flowable grindstone raw material in the grindstone raw material adjusting steps P20 and P21, and is poured into the forming die in the forming step P22, When sintering is performed in the sintering step P25, since the particles are precipitated as particles sufficiently smaller than the abrasive particles 12 and are combined with the abrasive particles, for example, the abrasive particles 12 are fine particles having a particle size of # 3000 or more, that is, an average particle size of 6 μm or less. Even so, the vitrified grindstone 10 capable of performing a grinding process of the surface quality of the workpiece corresponding to the abrasive grain size is formed because the grain size is further reduced by precipitation compared to the grain size of the abrasive grains 12. can get.

  Further, according to this embodiment, the vitreous binder raw material liquid 2 is a sol liquid, which can be changed into a gel in the molding die in the molding step P23. And the mixture is gelled in the mold, so that the mold can be easily removed from the mold.

  Further, according to the present embodiment, the vitreous binder raw material liquid 1 or 2 is prepared from a mixture of metal alkoxides in which a plurality of constituent elements of the vitreous binder 14 are bonded to alkoxyl groups, respectively. It becomes possible to make the material constituting the vitreous binder into a solution.

  Further, according to the present embodiment, since the vitreous binder raw material liquid 2 is a metal alkoxide polycondensate obtained by subjecting a mixture of metal alkoxides to hydrolysis and polycondensation, the vitreous binder raw material liquid 2 can be easily prepared. A sol solution is obtained, and the amount of KOH (10%) added is small.

Further, according to this embodiment, the binder raw material liquid preparation steps P1 to P10 in FIG. 3 are represented by (a) a general formula Si (OR ¹ ) ₄ (where R ¹ is an alkyl group having 1 to 4 carbon atoms). And a condensed polymer of tetraalkyl silicate or silica, and Al represented by the general formula Al (OR ² ) _n · L _m (where R ² is an alkyl group, L is a ligand, and n + m = 3) First heating in which an alkoxide and a B alkoxide or a boron oxide alcohol solution represented by the general formula B (OR ³ ) ₃ (where R ³ is an alkyl group having 1 to 2 carbon atoms) are dissolved in an organic solvent and heated to reflux for the first heating. In the alkoxide solution refluxed in the refluxing steps P1 to P4 and (b) the first heating refluxing step P11, the alkoxide solution represented by the general formula Na (OR ⁴ ) (where R ⁴ is an alkyl group having 3 to ⁴ carbon atoms) 2nd heating reflux which introduces Na alkoxide and further heats reflux P8, (c) a cooling step P9 for cooling the alkoxide solution refluxed in the second heating / refluxing step P12, and (d) water and / or water having a hydrolysis rate of 0 to 100% with respect to the contained metal other than Na. Or a hydrolysis-condensation polymerization step in which acetic acid diluted with ethanol and an acid catalyst diluted with ethanol are sequentially added to partially hydrolyze and polycondensate the metal alkoxide in the alkoxide solution to obtain an alkoxide condensation polymer. P11 to P12 are included. In this way, the raw material liquid 2 in a sol state is obtained, and there is an advantage that a highly heat-resistant glassy binder 14 composed of oxides of four elements of Si, Al, B, and Na is obtained.

Further, according to this embodiment, the binder material liquid preparing step P1 to P10 in FIG. 2 or FIG. 3, the oxide composition of the vitreous bond _{SiO 2 70~90wt%, B 2 O} 3 10~20wt _{%, Al 2 O 3 1~5wt%} , so that the Na ₂ O1~5wt%, and the tetraalkyl silicate or silica polycondensate, and Al alkoxide, and B alkoxide or boron oxide alcoholic solution, the Na alkoxide the ratio is one which creates a binder material liquid 1 or 2 is set, SiO ₂ 70~90wt% oxide _{composition, B 2 O 3 10~20wt%,} Al 2 O 3 1~5wt%, Na There is an advantage that a highly heat-resistant vitreous binder 14 composed of _{1 to} 5% by weight of ₂ O is obtained.

According to the present embodiment, in the binder raw material liquid preparation steps P1 to P10 of FIG. 2 or FIG. 3, 0.03 to 0.3 mol of Al alkoxide and 0.1 to 0.3 mol of B alkoxide are used for 1 mol of tetraalkyl silicate. 2 to 0.5 mol of Na alkoxide and 0.05 to 0.25 mol of Na alkoxide are mixed in an organic solvent to produce a metal alkoxide, and 0 to 8 mol of water and / or acetic acid for hydrolysis is mixed and hydrolyzed. since the acid functions as a catalyst was further added 0~10mol is to obtain the alkoxide polycondensates or alkoxide composition as a binder material liquid, oxide composition SiO ₂ 70~90wt%, B ₂ O ₃ 10-20 wt%, there is the advantage that _{Al 2 O 3 1~5wt%, Na} 2 high vitreous bond 14 heat resistance consisting O1～5wt% is obtained.

  The raw material liquid 1 or 2 of the present embodiment is a vitreous binder raw material liquid for producing the vitreous binder 14 that binds abrasive grains in the process of manufacturing the vitrified grindstone 10, and the vitreous binder is used. 14 is composed of an alkoxide composition in which each of the plurality of constituent elements is bonded to an alkyl group, or an alkoxide polycondensate that is a polycondensate thereof. Is produced or precipitated in the process of producing a vitrified grindstone, the above-mentioned vitreous binder 14 can be used even if the abrasive grains 12 are fine grains having a size of # 3000 or more, that is, fine grains having an average grain size of 6 μm or less. Since a finer grain size is generated by precipitation than the grain size of No. 12, it is possible to perform grinding of the surface quality of the work piece corresponding to the grain size. Vitrified grinding wheel 10 that can be obtained.

  As mentioned above, although one Example of this invention was described using drawing, this invention is applied also to another aspect.

  For example, the vitreous binder 14 of the above-described embodiment was composed of oxides of four elements of Si, Al, B, and Na, but instead of Na, an alkali metal such as K and / or an alkali was used. They may be earth metals, may be composed of oxides of three elements among them, or may be glass containing oxides of other elements.

  In the above-described embodiment, the solution that has passed through the concentration step P10 is the raw material liquid 1 or 2. However, the solution that has not passed through the concentration step P10 may be the raw material liquid 1 or 2.

  Further, in the above-described embodiment, the raw material liquid 1 or 2 for producing the vitreous binder 14 is prepared by using the metal alkoxide of the element contained in the vitreous binder 14 or the metal sol solution or the like. Although the precursor is used, the metal sol solution or its precursor may be used by another method.

  The above is merely an example of the present invention, and the present invention can be variously modified without departing from the gist thereof.

It is the schematic which expands and demonstrates the structure of the vitrified grindstone of one Example of this invention. FIG. 2 is a process diagram illustrating a process for producing a raw material liquid of the vitreous binder of FIG. 1. FIG. 4 is a process diagram illustrating a process for producing a raw material liquid of another example of the vitreous binder of FIG. 1. FIG. 2 is a process diagram illustrating a manufacturing process of the vitrified grindstone of FIG. 1. It is a perspective view explaining the structure of the grindstone used for testing the performance of the vitreous binder of FIG.

Explanation of reference numerals

10: vitrified whetstone 12: abrasive 14: vitreous binder

Claims (8)

A vitreous binder raw material liquid for producing a vitreous binder that binds abrasive grains in the process of manufacturing a vitrified whetstone,
A vitreous binder raw material liquid for a vitrified grindstone, which comprises an alkoxide composition in which a plurality of constituent elements contained in the vitreous binder are each bonded to an alkyl group, or an alkoxide polycondensate which is a condensation polymer thereof. The vitrified grinding wheel according to claim 1, wherein the vitrified grinding wheel material liquid for vitrified grinding wheel produces a glassy binder having a coefficient of thermal expansion of 3 to 8 × 10 ⁻⁶ / ° C. in a process of manufacturing the vitrified grinding wheel. Vitreous binder raw material solution. The vitreous binder raw material liquid for a vitrified grinding wheel according to claim 1 or 2, wherein the plurality of constituent elements contained in the vitreous binder include four kinds of elements, Si, Al, B, and Na. 4. The vitrified grindstone glass material according to claim 1, wherein the vitreous binder raw material liquid is a sol liquid or a precursor thereof, and is converted into a gel in the vitrified grindstone forming die. Binder raw material liquid. The vitrified grinding wheel glass according to any one of claims 1 to 4, wherein the vitreous binder raw material liquid is prepared from a mixture of metal alkoxides in which a plurality of constituent elements of the vitreous binder are bonded to alkyl groups. Binder raw material liquid. The vitreous binder raw material liquid for a vitrified grinding wheel according to claim 5, wherein the vitreous binder raw material liquid is a metal alkoxide polycondensate obtained by subjecting a mixture of the metal alkoxide to hydrolysis and polycondensation. A method for producing a vitreous binder raw material liquid for producing a vitreous binder that binds abrasive grains in a manufacturing process of a vitrified whetstone,
In the binder raw material liquid preparation step, a tetraalkyl silicate or a silica polycondensate represented by the general formula Si (OR ¹ ) ₄ (where R ¹ is an alkyl group having 1 to 4 carbon atoms) and a general formula Al (OR ² ) _n L _m (where R ² is an alkyl group, L is a ligand and n + m = 3) and an Al alkoxide represented by the general formula B (OR ³ ) ₃ (where R ³ is the number of carbon atoms) A first heating and refluxing step of dissolving a B alkoxide or a boron oxide alcohol solution represented by formula (1 to 2 alkyl groups) in a solvent and heating to reflux,
An Na alkoxide represented by the general formula Na (OR ⁴ ) (where R ⁴ is an alkyl group having 3 to ⁴ carbon atoms) is charged into the alkoxide solution refluxed in the first heating reflux step, and further heated to reflux. A second heating reflux step;
A cooling step of cooling the alkoxide solution refluxed by the second heating reflux step;
Water and / or acetic acid having a hydrolysis rate of 0 to 100% with respect to the metal content excluding Na is diluted with ethanol, and an acid catalyst diluted with ethanol is sequentially charged to partially reduce the metal alkoxide in the alkoxide solution. And a hydrolysis-condensation polymerization step of subjecting the alkoxide condensation polymerization product to hydrolysis and condensation polymerization to obtain a vitrified grindstone raw material liquid for vitrified grinding wheels. 8. The method according to claim 7, wherein the Na alkoxide is obtained by dissolving metallic sodium in a boiled organic solvent and filtering the solution.

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