JPH02185373A - Synthetic grindstone - Google Patents

Abstract

PURPOSE:To eliminate the need for an abrasive oil material at polishing time, by dispersing an abrasive grain fine particle by relatively connecting in the matrix whose structure is composed of the uniformly mixing body of polyvinylacetal resin, at least one kind of heat hardening resin solidified body, the amorphous body of a silicate the abrasive oil material consisting of at least one kind of surface active agent. CONSTITUTION:In case of performing the polishing of an aluminum disk, the abrasive grain fine particle filled uniformly and compactly in the matrix resin having an excellent water resistance and abrasive grain holding power and connected mutually shows a sharp sharpness, i.e. polishing power together with the grindstone surface hardness caused by the optimum hardness, elasticity, brittleness, etc., of the matrix and the abrasive grain count, moreover the exuding of the contained abrasive oil material. Also the abrasive grain is reproduced by being re-newed immediately at its abrasive face with the new abrasive grain connected at the back appearing on the surface even if being dropped in order by the slide friction polishing action and the polishing chip, dropping abrasive grain, etc., are easy to be discharge from a continuous fine pore as well and also the contained abrasive oil material constrains the secondary cohesion of the polishing chip and dropped abrasive grain fine powder.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is a metal plate having a flat surface, such as a soft metal such as an aluminum alloy master disk (hereinafter referred to as an aluminum disk) that is a material for a magnetic disk base. It relates to a synthetic whetstone used for surface grinding and polishing, that is, polishing.

(Prior art) Conventionally, a relatively soft metal plate with a flat surface,
For example, surface polishing of aluminum disks, etc. can be done by machining using a precision lathe, so-called lapping using a slurry of fine powder such as silicon carbide, or processing using a synthetic grindstone such as a resinoid grindstone or a urethane grindstone. was common.

However, machining using precision lathes, etc. has different finishing accuracy and work efficiency depending on the skill level of the worker, and is generally poor in workability. The efficiency was noticeably low.

In addition, in the case of lapping processing using a slurry of low-grain fine powder such as silicon carbide, it is economically disadvantageous due to the loss of slurry and the amount used, and it also contaminates the surrounding working environment and workers, and furthermore, There was a problem in that it required a great deal of effort and expense to treat highly concentrated waste liquid.

In place of the lapping method using such a fine abrasive powder slurry, processing using a synthetic grindstone is rapidly becoming popular in recent years. However, synthetic whetstones, such as vitrified or resinoid hard whetstones, have insufficient polishing performance and may not be able to obtain a sufficient finish viscosity, lack retrieval ability, or cause undesirable phenomena such as clogging. However, there were problems such as inability to obtain a certain level of performance with high efficiency. That is, in polishing flat parts, especially in polishing 11 where flatness and surface precision are required at the same time, such as aluminum disks, the surface of the object to be polished and the surface of the abrasive material are brought into contact, and sometimes - It is necessary to proceed with polishing. For example, if a resinoid-based or urethane-based synthetic whetstone with an independent pore structure is used, polishing debris, fallen abrasive grains, etc. due to the polishing action can enter the pores and cause clogging. The polishing effect is not sustainable, and frequent dressing (surface renewal) work is required.

On the other hand, those using polyvinyl acetal resin with continuous pores as a bonding material are easy to discharge polishing debris, fallen abrasive grains, etc. to the outside of the pores, and are less likely to cause clogging, making them excellent synthetic grindstones. Although it is generally known, it has relatively poor water resistance and is not suitable for such precision polishing applications.

In addition, Tokkosho! contains a cured thermosetting resin for the purpose of imparting water resistance. No. 9-1888 and No. 53-
It has been proposed in various publications such as No. 6762, and is known as a water-resistant synthetic whetstone. In particular, in the latter invention, by changing the blending ratio of the thermosetting resin, an abrasive material with properties ranging from elastic to rigid can be obtained.
In particular, fine-grained whetstones were said to be useful for polishing soft, hard, and difficult-to-cut materials, but their grinding power was still insufficient, and they were particularly useful for polishing soft metal plates with flat surfaces. It was not suitable for flat surface polishing of aluminum disks, etc.

Furthermore, in order to compensate for the lack of Q quality resistance and anti-pressure of polyvinyl acetal grinding wheels, and to increase the adhesion and binding power of abrasive materials, a method of adding silicic acid gel to the matrix was proposed in Japanese Patent Publication No. 8G-2'. 2448, but the conventional synthetic grindstone manufactured by this method is similar to the above, and the soft metal plate publication limits the relationship between the surface hardness of the polyvinyl acetal grindstone and the abrasive grain count, and A synthetic whetstone in which silicic acid gel is added to the matrix has been proposed, and this synthetic whetstone simultaneously satisfies excellent flatness and high surface precision, especially for flat surface polishing of aluminum disks and the like. Then, this synthetic grindstone is attached to, for example, a lapping polishing machine, and an aluminum disk or the like is polished while the polishing surface is wetted with polishing oil. However, since this polishing oil is diffused around the polishing surface during polishing, the above polishing method has the problem of requiring a large amount of polishing oil.

Attempts have been made to collect and reuse the polishing oil in order to solve this problem, but since it contains a large amount of thin metal solids (less than 5 microns), ordinary filters quickly become obsolete. There was a problem.

(Problems to be Solved by the Invention) The present inventors have completed the present invention as a result of intensive research in view of the above-mentioned technical current situation and problems. This is applied to soft metal plates finished to satisfy both excellent flatness and high surface precision, especially aluminum disks, and especially annular disks made of special aluminum alloys used for extremely precise applications. To provide a synthetic whetstone which can be used and does not require a polishing oil during polishing.

(Means for Solving the Problems) The above object is to provide a structure having a three-dimensional network structure with continuous fine pores, which structure is formed by curing polyvinyl acetal resin and at least one thermosetting resin. a matrix consisting of a homogeneous mixture of an amorphous body, a silicate, and a polishing oil consisting of at least one type of surfactant; and abrasive fine particles that are interconnected with each other and exist in a substantially continuous state in the matrix. This is achieved by a synthetic whetstone characterized by being made of a mixture of

The fine three-dimensional network structure of the grindstone of the present invention is completely different from the closed cell structure of resinoid-based or urethane-based artificial grindstones; there are no closed cells, and branches extend three-dimensionally into the voids. The structure is like that, and the pores are infinitely connected. Therefore, abrasive particles and polishing debris caused by polishing work are easily discharged from the system through these gaps, and even if they are captured, they accumulate in the bubbles, as seen in other closed-cell structure grindstones, It is difficult to cause undesirable phenomena such as clogging. In the case of a closed-cell structure, the polishing effect is not sustainable due to clogging, and frequent dressing operations (surface renewal) are required.

The above-mentioned effects can be sufficiently obtained within the range of average pore diameter of 10 to 100 μm; below this range, the pores are too dense and phenomena such as clogging tend to occur. Moreover, if it exceeds this, the structure will be too rough and there will be some difficulty in terms of uniformity of physical properties.

Further, the porosity is preferably in the range of 60 to 86 by volume. If the capacity is less than 80, closed cells will be present, and if the capacity exceeds 85, the strength will be insufficient.

A synthetic whetstone using a hardened polyvinyl acecool resin, a thermosetting resin, and an amorphous silicate as a binder for abrasive grains is known from JP-A-61-1112480. Because it contains a hardened thermosetting resin, it is water resistant, and because it also uses an amorphous silicate, it has extremely favorable grinding power as a grindstone for polishing soft metals. There are few blemishes, and
This provides performance that makes it difficult to cause undesirable phenomena such as clogging. As mentioned above, when polyvinyl acetal resin is used in combination with a hardened thermosetting resin and an amorphous silicate as a matrix which is a binding material, the toughness (stickiness) peculiar to polyvinyl acetal synthetic grinding wheels is reduced. The synthetic whetstone has an appropriate degree of brittleness, and the amorphous silicate in particular has the excellent effect of imparting appropriate magic properties to the whetstone and improving its grinding power.

The thermosetting resin referred to in the present invention includes melamine resin,
Examples include phenolic resins, urea resins, thermosetting urethane resins, and epoxy resins, but melamine resins and phenol resins are usually used.

In the present invention, the amorphous silicate refers to a gel-like substance that is produced when acid is applied to various silicates made of silicon dioxide and various bases. For salt, NatOa x8i0*
It is represented by the chemical formula @yH*o,
It is preferable to use those having a molar ratio of Na 20/ 8 iot of 2 and 4. In this case, the general formula of the gel-like substance is an inorganic polymer represented by intermolecular crosslinking to form an amorphous three-dimensional compound. In addition to this, aluminum hydroxide or the like may be used as the base.

The above-mentioned binder matrix plays the role of effectively holding fine abrasive particles, which are the main material of polishing. During polishing work, one abrasive grain polishes the surface and is eliminated from the system. At the same time, new abrasive grains are produced spontaneously to continue the polishing work. In other words, the grindstone itself performs polishing while wearing itself out. However, by using the silicate amorphous material mentioned above, the matrix itself also undergoes some grinding. This can significantly improve the grinding force and at the same time reduce the wear of the grindstone itself.

Another component mixed into the matrix is a polishing oil consisting of a surfactant, which acts as a polishing oil when the grinding wheel itself wears out.
It gradually oozes out onto the surface of the whetstone and can improve the polishing power.

Here, a polishing oil made of a surfactant has the basic performance of improving grindability and finished surface roughness, as well as suppressing the phenomenon of secondary aggregation of polishing debris and fallen abrasive particles. Although there is no particular limitation as long as it has an effect, alkyl phosphate salts, polyoxyalkylene alkyl ethers, and the like are usually used.

The abrasive fine particles referred to in the present invention are made by pulverizing either a compound or a single abrasive material having abrasive power such as diamond, boron nitride, silicon carbide, fused alumina, garnet, emery, cerium oxide, chromium oxide, etc. It refers to those classified by an appropriate method to the particle size specified in JIS standard R8001, and at least one of the cemented carbide ceramic abrasive grains selected from the group consisting of silicon carbide, fused alumina, chromium oxide, and cerium oxide. It is desirable to select one type.

Another key point of the present invention is the coordination and distribution state of abrasive grains that have the New Calendar performance. In other words, in this type of synthetic whetstone, the abrasive grains existing on the polishing surface are rubbed off, fall off, and are discharged from the system repeatedly, and the whetstone reduces its own thickness while increasing the surface of the object to be polished. However, if the ratio of abrasive grains is small, each abrasive grain will exist independently, and after that abrasive grain falls off, from a microscopic perspective, only the binder will remain. Scrub the surface with. In other words, since the rubbing is performed in areas with low abrasive force, the sharpness (grinding force) is poor. Especially when the purpose is to polish the surface of a soft metal such as an aluminum disk, as in the present invention,
Such a phenomenon is undesirable and tends to lead to problems such as surface unevenness and abrasive unevenness.

In the present invention, in order to avoid such undesirable phenomena, individual abrasive grains do not exist independently in the matrix, but are interconnected with adjacent abrasive grains, forming a substantially continuous state. It is distributed. The condition of such abrasive grains is
The matrix of the grinding wheel according to the present invention has a capacity of 60 to 85 -
It has a high porosity and is uniformly connected three-dimensionally.
It has a continuous pore structure with an average pore diameter of 10 to 100 μm, and a sufficient amount of fine abrasive grains of appropriate grain size are arranged in a so-called crowd in the microskeleton of such a matrix, and are uniformly distributed. It comes from being there. In order to ensure such coordination and distribution, a suitable abrasive grain count is at least 800, and the content is at least 26 weights of the mixture weight, more preferably at least 50 weights of the mixture weight. .

Further, it is preferable that the lower the abrasive grain count, that is, the larger the diameter of the abrasive grains, the higher the hardness.

The grindstone according to the present invention is manufactured by the following method.

That is, the average degree of polymerization is 300 to zooo, and the degree of IN is 80.
An aqueous solution is prepared by mixing one or more moles of polyvinyl alcohol, its derivatives or modified products, and an aqueous solution, non-aqueous solution, or emulsion of a precursor consisting of a monomer, oligomer, or polymer of a thermosetting resin. etc., and an aqueous solution or colloid of silicate, stirred uniformly, and further added with abrasive grains, aldehydes as a crosslinking agent, acids as a catalyst, starches as a pore-forming agent, etc., to prepare a uniform viscous slurry. This is then cast into a predetermined mold. After that, the reaction is solidified at a temperature of 40 to 100°C day and night in a hot water bath or other bath, and then taken out and washed with water to remove excess aldehydes, acids,
The pore forming agent is removed to obtain an intermediate.

Next, an aqueous solution, non-aqueous solvent solution, emulsion, etc. of a precursor made of a thermosetting resin monomer, oligomer or polymer, etc., and a polishing oil made of a surfactant are added to prepare a uniformly stirred solution, This is impregnated with the intermediate, squeezed to a predetermined amount, heated at a temperature of about 100°C to evaporate water, and dried. Thereafter, heat treatment (curing) must be performed to cure the resin, but the temperature and time required for curing vary slightly depending on the type and amount of resin used.

Generally, curing is carried out at 100 to 250° C. for 20 to 100 hours to achieve the curing reaction.

If curing is insufficient, the toughness will be large, and if the curing conditions are harsh and curing progresses too much, thermal decomposition will occur at the same time, which is likely to cause undesirable phenomena, so conditions must be selected carefully. In order to avoid rapid temperature increases, it is also effective to increase the temperature in stages or to perform the process in an inert gas atmosphere to suppress local oxidation and deterioration. Furthermore, it is also effective to use a catalyst to promote thermal curing.

In addition, as an intermediate, an aqueous solution, a non-aqueous solution of a precursor consisting of a thermosetting resin monomer, oligomer or polymer, etc.
After impregnating with a solution such as emulsion and squeezing it to a specified amount, 1
Heat at a temperature of about 00"C to remove water by evaporation and dry.
The synthetic grindstone of the present invention can also be obtained by impregnating a cured product with an abrasive oil made of a surfactant, squeezing it to a predetermined temperature of 11, heating it at a temperature of about 100"C to evaporate water, and drying it. be able to.

The liquid resin may be an aqueous solution, a solution dissolved in an organic solvent, an emulsion, or a resin stock solution.
From the viewpoint of workability and ease of controlling the mixing ratio,
The method using an aqueous solution is most preferred.

(Function) After the grindstone obtained as described above was molded into a desired shape, it was placed in water and left for 12 hours or more to reach a completely wet state and swelled by a maximum of 2% and stabilized. It is used for surface polishing of soft metals, but especially when used for very precise purposes such as surface polishing of special aluminum alloy annular disks such as aluminum disks, the thickness before and after polishing, that is, the accuracy of the grinder, Because it is highly defined and the variation in flatness and thickness is extremely suppressed, it cannot be applied to general polishing equipment. It is preferable to use it. Here, a double-sided lapping type polishing machine is equipped with circular or ring-shaped metal surface plates on both the upper and lower surfaces, and one or more objects to be polished are sandwiched between them and crimped, and both the upper and lower surface plates are rotated in opposite directions. This refers to a device that performs polishing by rotating the grinding wheel to slide and scrape the surface of the object to be polished. When applying the grinding wheel of the present invention, it is attached to both surface plates so that the grinding wheel forms a uniform surface. It is used as such.

(Then, when the grinding wheel of the present invention is installed in a double-sided lapping type polishing machine to polish, for example, an aluminum disk, it is evenly and densely packed into the matrix resin, which has excellent water resistance and abrasive grain retention. The interconnected abrasive fine particles have appropriate hardness, elasticity, and
Is it fragile? The surface hardness of the grinding wheel, which is derived from the grinding process, and the bleeding of the abrasive oil contained in the grinding wheel result in a sharp sharpness, or abrasive power. New connected abrasive grains appear on the surface,
The abrasive surface is immediately renewed and regenerated, and polishing debris, fallen abrasive grains, etc. are easily discharged from continuous fine pores, and the contained polishing oil suppresses secondary M collection of polishing debris and fallen abrasive grain fine powder. Since clogging does not easily occur, high polishing power is maintained over a long period of time. In addition, due to the above-mentioned special coordination and distribution state of the ultrafine abrasive grains of the grindstone of the present invention, during polishing work, there is no rubbing phenomenon caused only by the matrix resin.
The abrasive particles contact and rub over the entire surface of the flat object to be polished,
Uniform polishing action is always performed.

Therefore, the grinding wheel of the present invention efficiently provides a soft metal plate having a flat surface with high smoothness without polishing spots and excellent finished surface accuracy.

(Example) Embodiments of the present invention will be described below with reference to Examples.

The polishing equipment, measuring instruments, object to be polished, etc. used in this example are as follows.

・Polishing equipment: Vertical copper roller polishing machine ・Surface roughness meter: Surface roughness meter manufactured by Tokyo Seimitsu Co., Ltd. (model: Surfcom 5B3A) ・Abraded material: Copper roller for gravure printing (diameter 11
0mm x length 100100O The polishing conditions and measurement conditions are as follows.

- Calendar conditions - Load: 85KC7 - Grinding wheel rotation speed: 70 orpm - Grinding wheel feed speed: mm7 minutes - Roller rotation speed: 11 orpm - Polishing: 2 round trips (1 m x 4 times) - Evaluation of polishing amount - Roller polishing amount (unit: μm) = Roller diameter before polishing - Roller diameter after polishing/Wheelstone wear amount (unit: mm) == Grindstone thickness before polishing - Grindstone thickness after polishing/Surface accuracy measurement conditions Note that Ra l Rmax here indicates the parameter of the following formula.

Ra ''' Centerline average roughness Ra = 110Ll f (x) ldxf (x) indicates the roughness curve.

Rmax... Maximum height Rmax = Pmax - Vmin Pmax... Maximum peak height Vmin in the roughness curve
... Silicon carbide powder No. 3000 was selected as the maximum valley depth abrasive grain. No. aooo has an average particle size of 4.1 to 5.9 μm. Polymerization degree 170G
, Completely saponified polyvinyl alcohol was made into an aqueous solution, and a water-soluble phenol resin was added to it as a water-soluble phenolic resin, PR manufactured by Jurez Co., Ltd.
- After adding a predetermined amount of 861 people, sulfuric acid as a catalyst, formaldehyde as a crosslinking agent, and tenocone starch as a pore-forming agent, and further adding a predetermined amount of an aqueous solution of silicate containing silicon dioxide and soda ash, as described above. A uniform slurry liquid was prepared by mixing with abrasive grains. This slurry liquid was cast into a predetermined mold, and reacted and solidified at 60°C for one day and night. Thereafter, it was washed with water to remove excess acid, formaldehyde, cornstarch, etc., and dried to obtain an intermediate for a synthetic grindstone. In addition, as an aqueous solution of melamine resin, a predetermined amount of the rumored aqueous solution of Sumitomo Deerez Sanmaki M-3, Bell Coolant I Got (main component higher fatty acid amide, higher fatty acid ester salt) manufactured by Kanebo Co., Ltd., Bell Coolant 1002 (main component alkyl ester salt), acid ester salt, polyoxyalkyl ether),
Daiichi Kogyo Seiyaku e? Prepare a solution in which a predetermined amount of 3i glycerin 13G is uniformly stirred, impregnate it with the intermediate,
After squeezing to a predetermined amount, dry it at a temperature of 130℃ for about 60℃.
A synthetic whetstone was obtained by heat treatment for a period of time.

The composition of the grindstone used in this example is shown in Table 1.

Next, this synthetic whetstone was attached to a polishing device, and polishing was performed under the predetermined conditions of the polishing device. After polishing for a predetermined period of time, the surface shape of the polished material was inspected.

The results are shown in Table 1.

(Margin below) Table 1 Next, the intermediate prepared in the example in Table 1 was impregnated with an aqueous solution of Showa Polymer 8M-700 as a resin and squeezed to a predetermined amount. It was dried, heat-treated at a temperature of 150° C. for about 50 hours, impregnated with a predetermined amount of Bell Coolant 1001 and Bell Coolant 1002 manufactured by Kanebo Co., Ltd., and squeezed to a predetermined amount to obtain a synthetic whetstone.

The composition of the grindstone used in this example is shown in Table 2.

Next, this synthetic whetstone was attached to a polishing device, and polishing was performed under the predetermined conditions of the polishing device. After polishing for a predetermined period of time, the surface shape of the polished material was inspected.

The results are shown in Table 2.

(Left below) As is clear from Tables 1 and 2, the synthetic whetstone of the present invention has appropriate grinding power and surface placement accuracy even without being wetted with abrasive oil during polishing. It also shows good results. It can be seen that Rmax shows a value of approximately 10 to 14 compared to Ra, indicating that there are few scratches and a good finish.

(Effects of the Invention) As described in detail above, the synthetic grindstone according to the present invention does not require a polishing oil during polishing, and therefore has the effect of reducing processing costs.

In addition, the synthetic whetstone according to the present invention makes it possible to efficiently and economically obtain soft metal plates, such as aluminum disks, which have both excellent flatness and high surface precision, and is used in the electronic industry, office equipment, etc. Information S′ accompanying the development of industry, etc.
The contribution to industry will be significant, as it will be able to sufficiently address the rapid increase in demand and improve the quality of high-precision finished aluminum disks used as bond media.

Applicant Kanebo Co., Ltd.

Claims (2)

[Claims] (1) A structure having a three-dimensional network structure with continuous fine pores, the structure forming an interface between a polyvinyl acetal resin, at least one type of cured thermosetting resin, and at least one type of amorphous silicate. A synthetic whetstone characterized by comprising a matrix consisting of a homogeneous mixture with a polishing oil consisting of an activator, and a mixture of fine abrasive particles interlocking with each other and existing in a substantially continuous state in the matrix. . (2) The synthetic grindstone according to claim 1, wherein the content of the polishing oil made of the surfactant is in the range of 1 to 10% by weight.