JP2007246732A - Abrasive material, abrasive and their manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new abrasive material, abrasive and their manufacturing method. <P>SOLUTION: A carbonized material is obtained by carbonizing a cedar material as a raw material at a carbonization temperature of 600°C for a predetermined carbonizing time. A material having been prepared by adjusting the carbonized material so as to have a predetermined particle size range is used in a polishing process of a lens as an abrasive material. A mixture composition with cerium carbide, etc., may be used as an abrasive material, and the carbonized material may be dispersed in water to give a liquid colloid and be used for polishing in the state of dropping. Compared to a conventional abrasive material mainly composed of cerium oxide, this abrasive material can perform highly accurate polishing in a short time and can provide a detoxified abrasion process by purifying a polishing waste liquid. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a variety of optical lenses such as video camera lenses and digital camera lenses, pickup lenses for DVDs and CDs, and optical devices in industrial fields such as the camera industry, the medical endoscope industry, and the optoelectronics industry. The present invention relates to a polishing material used for polishing a semiconductor device, a prism as a laser device, a reflecting mirror, a mirror surface or an interface, and a manufacturing method thereof.

  Conventionally, various polishing materials such as cerium oxide and zirconium oxide (hereinafter referred to as “current polishing material”) have been used, and various polishing materials using these current polishing materials as raw materials have been proposed (for example, see Patent Document 1). ). This material proposes an abrasive using cerium oxide as a raw material.

  Incidentally, a lens is generally processed through steps of rough grinding, fine grinding, and polishing. The glass is ground to a predetermined shape and surface roughness by rough grinding, the surface roughness and curvature are finished with high precision by fine grinding, and the surface is polished by polishing to give predetermined optical performance. These are performed by a grinder equipped with a grindstone, and diamond grits are hardened with a bond material as a grindstone. Electrodeposited bonds fixed by Ni plating, iron oxide, aluminum oxide, silicon oxide and other inorganic substances such as There are mixed and fired vitrified bonds, metal bonds obtained by sintering metal powders such as bronze, and resin bonds obtained by mixing hard resins. These are all expensive. For fine grinding, a metal bond grindstone or diamond resin grindstone (diamond pellet) is used. However, in this precise grinding, the abrasive grains used in the grindstone are high in hardness and lack of slidability, so scratches on the lens surface (grinding scratches) Will result. Polishing is a process in which scratches generated by fine grinding are completely removed to finish a smooth surface, and at the same time, the shape accuracy of the spherical surface is increased, and includes 5 to 10% by weight of fine particles of inorganic oxides such as cerium oxide and zirconium oxide. The liquid is circulated down or the liquid droplets are circulated and dropped, and the hydration layer formed on the lens surface is finely removed or filled with a polishing material to make it smooth.

  However, the above-described inorganic oxide (currently used polishing material) is expensive, and requires a high level of technology for blending and preparing it. In addition, there is a disadvantage that long polishing is required to improve polishing accuracy. On the other hand, due to the rapid progress of the above-mentioned optical electronics industry, for example, polishing of microlenses, ultrafine prisms and mirror surfaces is required to develop completely new ultra-high precision polishing technology and polishing materials used therefor. . Further, a polishing waste liquid is generated by circulating and dropping the inorganic oxide droplets, and it is necessary to purify the polishing waste liquid.

  Furthermore, as a polishing material for lenses formed from new lens materials such as fluorite and synthetic quartz, it is difficult to supply bastonite mainly composed of rare earth element oxides, and it is derived from natural products. There is also a circumstance that it is necessary to find raw materials for ore materials that inevitably have variations in quality.

  On the other hand, charcoal obtained by carbonizing wood has been studied by the present inventors and other studies so far that hardness, slidability, porosity, etc. are remarkably expressed depending on the carbonization temperature and carbonization time. Has been revealed.

JP 2005-48181 A

  Therefore, in view of the above circumstances, the present inventors can supply cheaply and stably in place of bust tonesite, diamond, etc., and realize higher polishing performance and self-purification of polishing waste liquid. An object of the present invention is to provide an abrasive material and an abrasive material to be obtained. As the background of this object, the following objects and problems have been achieved by realizing the present invention by fusing each other. In other words, the use of cedar wood (thinned wood / unused wood), which is a forestry resource, by expanding its use through new application development, effective use, high value added use, surface / interface / mirror polishing materials and polishing materials for cutting-edge optical / electronic materials New development, development of environmental non-loading polishing material, and detoxification of polishing waste liquid.

Means for solving the problems and actions / effects of the invention

  In order to achieve the above object, the present inventors have found that wood carbide is used as an abrasive material in place of bust necite, diamond and the like, and have completed the present invention after conducting various tests. The present invention is a wood carbide having performance and shape that can accurately correspond to the polishing process of the material to be polished, and this wood carbide is used alone, or the wood carbide is used for current polishing such as cerium oxide and zirconium oxide. The mixed composition mixed with the material is used as an abrasive material or an abrasive. As a result, higher polishing performance and purification of polishing waste liquid can be realized, and cost reduction can also be realized. In addition, the wood used as the material for this polishing material is inexpensive and easy to process, and the carbonization of wood can utilize the inherent thermal decomposition and oxidation self-heating reactions of wood, saving energy and reducing the environment. In addition, the process can be performed without any load, and low-cost production is possible.

  The present inventors regard the physical and chemical properties that change significantly depending on the carbonization temperature and carbonization time of wood as functions, and in particular, ensure hardness, slidability, and porosity as factors for developing the polishing performance. The present invention was completed by using an abrasive material having a fine particle size of That is, by controlling the carbonization temperature and the carbonization time among various carbonization conditions, the charcoal becomes hard due to the change in the bonding state and crystal structure of the wood carbide (charcoal), while the charcoal is slid by the transition to a graphite-like structure. It has been found that the pores and the distribution of the pores generated in the cell wall of carbonized wood can be controlled. Its hardness is second only to diamond, and it exhibits sharp grinding / polishing performance. On the other hand, its slidability while maintaining its high hardness gives lubricity to grinding / polishing and scratches on the lens surface. It will prevent generation. It also helps to improve the dispersion of the liquid emulsion of fine charcoal particles having micropores to macropores and having a particle size of 100 nm to 500 μm, and ensures an excellent liquid colloidal abrasive solution having a uniform abrasive grain distribution.

  Specifically, the present invention is specified by the following matters. That is, in the invention according to claim 1, as a polishing material, a wood carbide that is carbonized at a predetermined carbonization temperature and a predetermined carbonization time and is prepared in a powder or granular form with a predetermined particle size, either alone or The wood carbide is composed of a mixed composition in which an inorganic material containing one or more of cerium oxide, zirconium oxide, and diamond is mixed. As a result, a porous powdery or granular abrasive material having micropores (micropores), macropores (macropores), or mesopores intermediate between them is obtained. The particle size of the wood carbide or the mixed composition mixed with the wood carbide can be set in a range of 100 nm to 500 μm (Claim 2). Further, the mixed composition may have at least 5% by weight as the wood carbide and at least 5% by weight as the inorganic substance (Claim 3).

  In the invention according to claim 4, a porous carbonized fiber made of porous carbon nanofibers or activated carbon fibers having a predetermined diameter and a predetermined length is used as the polishing material, either alone or in the form of carbon. It was constituted by a fiber mixture composition in which a chemical fiber and an inorganic material containing at least one of cerium oxide, zirconium oxide and diamond were mixed. The carbonized fiber may have a fibrous form having a diameter of 50 nm to 500 μm and a length of 100 μm to 0.5 mm. Further, the mixed composition may have at least 5% by weight as the carbonized fiber and at least 5% by weight as the inorganic substance.

  On the other hand, the polishing material according to any one of claims 1 to 6 is dispersed in water in an amount of 0.0001 to 0.1% to form a liquid colloid to obtain a liquid polishing material or a liquid polishing material. (Claim 7). Further, the abrasive material according to any one of claims 1 to 6 is 0.01% by weight to one or more selected from high-strength and high-modulus fibers including carbon fiber, aramid fiber or Japanese paper. 5% by weight can be mixed and molded into a sheet to obtain a sheet-like abrasive or sheet-like abrasive (claim 8). Furthermore, the abrasive material according to any one of claims 1 to 6 is mixed with a bond material or a hard resin, filled into a mold having a predetermined shape, and molded into a grindstone-like abrasive material or grindstone-like abrasive. (Claim 9).

  And as a manufacturing method of polishing material, when manufacturing the wood carbide which comprises the polishing material in any one of said Claims 1-3, the conditions about the carbonization temperature and carbonization time are changed and set. Thus, it is possible to manufacture a polishing material that exhibits functions corresponding to the performance required in each of the three steps of rough grinding of an optical lens, fine grinding for forming a semi-gloss surface, and final finishing polishing. 10).

  In addition, in this method of manufacturing an abrasive material, the type of carbonization raw material for obtaining the wood carbide and the portion to be used in response to the performance required in each of the three steps of rough grinding, fine grinding and polishing are as follows. It is possible to selectively change and set (claim 11).

<First Embodiment>
For broad-leaved trees, especially Umegamegashi and oak are used, and for coniferous trees, cedar is used. The carbonized raw material selected from these is first subjected to 300 to 400 ° C. for 5 to 7 hours with air shut-off, and then supplied with air at 1300 to 1350 ° C. for 1 to 3 hours. After refining by heating, it is quenched and extinguished using charcoal containing 10 to 20% moisture. The obtained charcoal is prepared into a powdery or granular form having a predetermined particle diameter to form a wood carbide, and this wood carbide is used as a polishing material. This abrasive material is fixed using a bond material, and used as a grindstone (grindstone-like abrasive) for grinding.

Second Embodiment
For broad-leaved trees, white birch, cypress, abragi or basamushi are used, and for coniferous trees, cedar, red pine, black pine or todomatsu are used. With respect to the carbonization raw material selected from these, it set to the temperature increase rate of 0.5-20 degreeC / min, and selected from the range of 200 degreeC-1500 degreeC 400 degreeC, 500 degreeC, 600 degreeC, 800 degreeC, 900 degreeC, 1000 The wood carbide is obtained by raising the temperature to 1 ° C., 1100 ° C., 1200 ° C., and 1300 ° C., and maintaining each of these temperatures to perform air shut-off heating. Next, the obtained wood carbide is prepared into abrasive grains having a particle size distribution with a particle size of 100 nm to 500 μm. Each abrasive grain having a different carbonization temperature is used as a resin grindstone (pellet) in the fine grinding process. Compared to diamond pellets, scratches are not generated on the lens surface, and the occurrence of “burns” and “cloudiness” can be prevented and suppressed.

<Third Embodiment>
Cedar is selected as the upper carbonization raw material, 600 ° C. is selected as the carbonization temperature condition, carbonization is performed by the same carbonization method as described in the second embodiment, and the obtained wood carbide is subjected to the same particle size distribution as above. 0.005% by weight, 1% by weight or 10% by weight is added to the current polishing material mainly composed of cerium oxide and mixed, and this mixed composition is dispersed in water. It is made into a liquid colloid by making it into a liquid abrasive. Then, the liquid abrasive is circulated so as to be dropped in a droplet state with respect to the object to be polished in the polishing step, and the dropping polishing is performed.

<Fourth embodiment>
0.001 weight by weight of a porous carbonized fiber composed of porous carbon nanofibers or activated carbon fibers having a diameter of 50 nm to 500 μm and a length of 100 μm to 0.5 mm with respect to the current polishing material mainly composed of cerium oxide % Or at least 0.001% by weight, and the mixture is further dispersed in water to form a liquid colloid to obtain a liquid abrasive. Then, the liquid abrasive is circulated so as to be dropped in a droplet state with respect to the object to be polished in the polishing step, and the dropping polishing is performed.

<Carbonized raw material>
Various tests were performed. The following were used as the carbonization raw material used for the test. That is, the cedar thinning material of the age of 18-20 years in the Takayanagi district of Niigata Prefecture was used as a cedar material. This cedar thinning was provided by the Niigata Forestry Association. For comparison, cypress, Japanese abragiri, and birch were also used. Hononaki and Japanese Aburaki obtained from Niigata Prefecture 10-15 years old wood from the Japan Federation of Forestry Associations. The birch was obtained from Korikawa-cho, Hokkaido, 10-year-old wood from Ory Giken Co., Ltd. Furthermore, bamboo charcoal is a topical woody carbonized material, and 5-6 year old mosouchiku was provided by the Forestry Union Federation to prepare bamboo charcoal. These carbonized raw materials were raw materials and dried materials, and their bark. In addition, three kinds of moso-chiku were used: raw material, desiccant and preheat-treated desiccant.

<Carbonization>
The carbonization apparatus was originally developed and used for the heat treatment and carbonization of the chemical raw material. Carbonization is sealed air shut-off heating, the furnace heating rate is set to 1-5 ° C / min, and after reaching a predetermined target set temperature in the range of 200-1500 ° C, it is held for 2 hours, and then Allowed to cool. The marking carbonization temperature was the internal temperature, and the uncarbonized material and heat-treated material were also used for the test material.

<Granularity adjustment>
Since ultrafine pulverization of wood and its carbides is extremely difficult, the planetary rotary pot mill (manufactured by Ito Seisakusho Co., Ltd.) was further improved and subjected to ultrafine pulverization. As the particle size adjustment method, the particle size was adjusted by a combination of the planetary rotation speed and rotation time during pulverization. The obtained powder was classified according to the particle size distribution, and subjected to polishing for each category.

Samples of cedar and thinned wood that had not been developed in the core material had a high rate of dispersion and diffusion into the polishing water, and the polishing performance was kept uniform.

<Grinding / Polishing>
Polishing was performed under the actual working conditions of each actual polishing process in the factory, and the evaluation was evaluated and evaluated based on the evaluation criteria of the shipping certification, which is usually performed by the skilled engineer in charge.

<Results obtained>
The heat treatment and carbonization temperature dependence was recognized in the polishing performance of the carbonized material. That is, in the polishing of lenses and prisms, carbides (carbonized products) in the carbonization temperature range of uncarbonized to 400 ° C. are suitable for rough polishing, and those in the carbonization temperature range of 400 to 1500 ° C. are used for each polishing step. The polishing performance was shown. Further, it was recognized that the hard polishing was appropriate in the carbonization temperature range of 800 ° C. or higher.

  Further, the dependence of the material particle size on the polishing performance of the test material was recognized, and the performance of the cedar carbide (carbonized material) having a particle size distribution of several tens of nanometers to several tens of micrometers was superior to that of the current polishing material.

  As described above, the cedar carbonized product whose function is controlled by the heat treatment temperature, carbonization temperature and particle size can be used alone or as a mixed composition depending on the type of polishing process, and it is selected appropriately. Therefore, it is considered that more accurate polishing and a wide range of polishing can be realized in each process.

  In the polishing using the cedar carbonized material as the polishing material, no scratches, cloudiness or burns were observed on the glass surface compared with the conventional and current polishing materials, and a marked improvement in the polishing rate was recognized. In addition, it was confirmed that the carbonization product of cedar was added, blended, and combined with conventional and current polishing materials, and no reduction in polishing performance was observed. It was. Further, in the polishing using the cedar carbonized product as the polishing material, no harmful components remained in the polishing waste liquid, and a remarkable polishing waste liquid purification function was recognized as compared with the current polishing material.

<Specimen>
As shown in FIG. 1, the current abrasive material alone (shown as [A] in the figure), the abrasive material composed of the wood carbide alone of the invention (shown as [B] in the figure), the current abrasive material and the present invention Two types of abrasive materials composed of a mixed composition with wood carbide (shown as [A] + [B] in the figure), an abrasive material composed of a mixed composition of the current abrasive material and the carbon nanofibers of the present invention ( A comparative test was conducted using [A] + [C] in the figure.

  [A] is a cerium oxide-based current polishing material containing 45 to 60% cerium oxide CeO2 and LaO3 and others. [B] is set to 600 ° C. as a carbonization temperature condition using cedar, carbonized by the carbonization method described in the second embodiment, and the obtained wood carbide has a particle size distribution in a particle size range of 100 nm to 500 μm. It was prepared to have.

<Test method>
Dropping polishing was performed for a predetermined time (300 seconds or 600 seconds) with each of the specimens of each polishing material having a polishing water dispersion concentration of 10%. And the comparison of the grinding | polishing precision by observing the Newton interference fringe after grinding | polishing, and observation of the generation | occurrence | production state of tingling and cloudiness by visual observation were performed. In addition, the rare metal concentration in the polishing waste liquid was detected and measured.

<Test results>
When the current polishing material of the above specimen [A] is polished for 300 seconds, there are 3 to 5 Newton interference fringes (see the photograph shown in FIG. 2), and the polishing accuracy is limited to a normal level. On the other hand, the polishing material of [B] according to the present invention alone, the polishing material made of the mixed composition of [B], and the polishing material made of the mixed composition of carbon nanofibers of [C] have long and short polishing times. Regardless of the case, the Newton interference fringes were realized with high accuracy of 1 to 2 (see the photograph shown in FIG. 3). In particular, the polishing accuracy when polishing is continued for 600 seconds with [A] of the current polishing material alone, and the polishing accuracy at 300 seconds in the above-mentioned carbide [B] of the present invention alone or in the mixed composition. It was found that they were comparable to each other and exhibited high polishing performance from the viewpoint of polishing efficiency.

Furthermore, in the rare metal concentration of the polishing waste liquid, 0.1 to 0.3 mg / m ³ of cerium oxide or lanthanum oxide was detected after the polishing time in the case of [A] of the current polishing material alone, Even if only 0.005 wt% of the carbide [A] of the present invention is mixed, there is no significant concentration detection as a rare metal concentration, and it is considered that the self-purifying function of the carbide is exhibited.

  In addition, when the above-mentioned specimen was used and the polishing process was omitted for the lens to be polished and the polishing process was performed for 15 to 30 minutes, the Newton interference fringes with high accuracy of 1 to 2 were obtained. Polishing could be realized. This is considered to suggest the possibility of a new polishing method.

It is the table | surface which put together the specimen and test result of Example 2 of this invention. It is an observation photograph of Newton interference fringes. It is an observation photograph of Newton interference fringes different from FIG.

Claims (11)

A wood carbide that has been carbonized at a predetermined carbonization temperature and a predetermined carbonization time and that has been prepared in the form of powder or granules having a predetermined particle size, either alone or with this wood carbide and cerium oxide, zirconium oxide, diamond A polishing material comprising a mixed composition obtained by mixing any one or more inorganic substances. The abrasive material according to claim 1,
A polishing material, wherein the particle size of the wood carbide or a mixed composition mixed with the wood carbide is set in a range of 100 nm to 500 μm. The abrasive material according to claim 1 or 2,
The abrasive composition, wherein the mixed composition has at least 5% by weight as the wood carbide and at least 5% by weight as the inorganic substance. A porous carbonized fiber composed of porous carbon nanofibers or activated carbon fibers having a predetermined diameter and a predetermined length, either alone or with this carbonized fiber and either cerium oxide, zirconium oxide or diamond A polishing material comprising a fiber mixed composition obtained by mixing an inorganic material containing one or more. The abrasive material according to claim 4,
The carbonized fiber has a fibrous form having a diameter of 50 nm to 500 μm and a length of 100 μm to 0.5 mm. The abrasive material according to claim 4 or 5, wherein
The polishing composition, wherein the mixed composition has at least 5% by weight as the carbonized fiber and at least 5% by weight as the inorganic substance. A liquid abrasive comprising the abrasive material according to any one of claims 1 to 6 dispersed in water in an amount of 0.0001 to 0.1% by weight to form a liquid colloid. The abrasive material according to any one of claims 1 to 6, with respect to one or more selected from high-strength and high-modulus fibers including carbon fiber, aramid fiber or Japanese paper, 0.01 wt% to 5 wt% % Sheet-like abrasive material that is mixed and molded into a sheet. A grindstone-like abrasive formed by mixing the abrasive material according to any one of claims 1 to 6 with a bond material or a hard resin and filling a mold having a predetermined shape. When manufacturing the wood carbide constituting the polishing material according to any one of claims 1 to 3, by changing the conditions for the carbonization temperature and carbonization time, rough grinding of the optical lens, semi-gloss A method for producing an abrasive material, which produces an abrasive material that exhibits a function corresponding to the performance required in each of the three stages of fine grinding to form a surface and polishing for final finishing. A method for producing an abrasive material according to claim 10,
Corresponding to the performance required in each of the three steps of rough grinding, fine grinding, and polishing, the material type of the carbonized raw material for obtaining the wood carbide and its use site were selectively changed and set. A method for producing an abrasive material.

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