JP2979685B2 - Whetstone for soft metal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft metal grindstone suitable for polishing a soft metal such as aluminum or copper, for example, an aluminum substrate used as a material for a magnetic disk substrate.

[0002]

2. Description of the Related Art Conventionally, soft metals such as aluminum and copper,
For example, a method using a slurry of fine particles such as silicon carbide or a method using a polyvinyl alcohol-based grindstone is generally used for polishing an aluminum substrate used as a material of a magnetic disk base.

[0003]

However, in the method using the fine particle slurry, scratches are liable to occur, and in the method using the polyvinyl alcohol-based grindstone, it is difficult to increase the finished surface accuracy and to prevent the generation of scratches. However, there is also a problem that the grinding wheel surface is easily clogged and the polishing efficiency is poor.

[0004] The present invention has been made in view of the above circumstances,
An object of the present invention is to provide a soft metal whetstone which is unlikely to cause scratches, has good finished surface accuracy, and hardly causes clogging.

[0005]

The present inventors have conducted intensive studies to achieve the above object, and as a result, the phenolic resin and the acrylic resin were further added to the polyvinyl acetal resin and the abrasive particles in a specific amount. In addition, it has been found that the formed soft metal grindstone can increase the surface accuracy of the object to be polished, hardly cause scratches, and can also prevent the occurrence of clogging of the grindstone surface.

That is, since the soft metal grindstone uses a phenolic resin and an acrylic resin in a specific amount in combination, the structure is soft and dense, and the structure is moderately brittle at the same time. The softening of the contact when processing contact with the object to be polished by the action of this prevents scratching and improves the surface accuracy, and also allows the grinding stone to drop off and discharge properly during polishing. Fine grindstone pieces are quickly removed together with the water of the polishing liquid due to the water repellency of the acrylic resin, preventing clogging of the grindstone and preventing the occurrence of scratches in this regard as well. The polishing rate can be maintained at all times, and the productivity can be greatly improved.

Accordingly, the present invention relates to a polyvinyl acetal resin of 20 to 28% by weight, abrasive fine particles of 50 to 70% by weight, a phenolic resin of 5 to 19% by weight and an acrylic resin of 1 to
A whetstone for a soft metal characterized by containing 15% by weight as a main component.

Hereinafter, the present invention will be described in more detail. The grindstone for a soft metal of the present invention comprises, as described above, a polyvinyl acetal resin, abrasive particles, a phenolic resin and an acrylic resin as main components.

Here, as the polyvinyl acetal resin, a resin obtained by allowing an aldehyde to act as a crosslinking agent on polyvinyl alcohol is used. In this case, the polyvinyl alcohol preferably has an average degree of polymerization of 400 to 2500 and a degree of saponification of 85 mol% or more, and one of these can be used alone or two or more kinds can be used in combination.
Examples of the aldehyde include formaldehyde, acetaldehyde, butyraldehyde and the like, and it is preferable to use 80 to 180 parts by weight per 100 parts by weight of polyvinyl alcohol. In addition, the compounding quantity of polyvinyl acetal resin shall be 20-28% (weight%, hereafter the same) of the whole grindstone.

Examples of the abrasive fine particles include fine particles of various polishing materials such as silicon carbide, fused alumina, calcined alumina, cerium oxide, chromium oxide, and silicon oxide. These can be used in combination. It is desirable that the abrasive particles have a particle size smaller than 800. The compounding amount of the abrasive particles is 50 to 70% of the whole grindstone.

The phenolic resin can be applied by a method of mixing with a slurry before being hardened as a grindstone as described later, or a method of impregnating pores of a grindstone after solidification,
Further, these methods can be used in combination. In addition, when including a phenolic resin by these methods,
The phenolic resin can be used in the form of an aqueous solution, a non-aqueous solvent solution, or an emulsion of a precursor composed of a monomer, an oligomer, or a polymer. The compounding amount of the phenolic resin is 5 to 19% of the whole grindstone. If it exceeds 19%, the surface accuracy may deteriorate and scratches may occur.

Next, as the acrylic resin, methyl ester, ethyl ester of methacrylic acid or acrylic acid,
Homopolymers and copolymers such as butyl ester are exemplified. The method of incorporating the acrylic resin into the grindstone is as follows. After preparing a grindstone having pores as described later, an aqueous solution of a precursor made of a monomer, oligomer or polymer of the acrylic resin, a nonaqueous solvent solution , Emulsion, etc., and then at 140-270 ° C for 5-10
A method of performing heat treatment for 0 hour can be suitably adopted.
In addition, the content of the acrylic resin is 1 to 15% of the whole grindstone.
Range. If the amount is less than 1%, scratches occur and the surface accuracy deteriorates, whereas if it exceeds 15%, clogging occurs.

The method for producing the soft metal grindstone according to the present invention is not particularly limited, but is preferably produced by the following method. That is, one or more kinds of polyvinyl alcohols are mixed to prepare an aqueous solution, and an aqueous solution of a precursor composed of a monomer, oligomer, or polymer of a phenolic resin, a non-aqueous solvent solution, an emulsion, and the like are added thereto. The mixture is further stirred uniformly, and further added with abrasive grains, aldehydes as a cross-linking agent, acids as a catalyst, starches as a pore-forming agent, etc. to prepare a uniform viscous slurry, which is poured into a predetermined mold. Type. Thereafter, the reaction is solidified in a hot water bath or other bath at a temperature of 40 ° C. to 90 ° C. for about one day and then taken out and washed with water to remove excess aldehydes, acids and pore-forming agents. The intermediate thus obtained is heated at a temperature of about 100 ° C. to remove water by evaporation and dried. Acrylic resin monomer,
An aqueous solution of a precursor comprising an oligomer or a polymer,
After impregnation with a non-aqueous solvent solution, emulsion, etc., 140
By performing a heat treatment for 5 to 100 hours at
The grindstone for soft metal of the present invention can be manufactured.

[0014]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

Examples and Comparative Examples Using the components shown in Table 1, a grindstone was prepared by the following method.
First, polyvinyl alcohol (completely saponified type with a polymerization degree of 5
(00: and a mixture having a polymerization degree of 1700 and a weight ratio of 7: 3)
Was added to water to form an aqueous solution, and a water-soluble phenolic resin was added thereto, followed by uniform stirring. Furthermore, silicon carbide abrasive grains GC30
No. 00, 150 parts by weight of formaldehyde as a cross-linking agent per 100 parts by weight of polyvinyl alcohol, hydrochloric acid as a catalyst, and 55 parts by weight of corn starch as a pore-forming agent per 100 parts by weight of polyvinyl alcohol were added and stirred and mixed. Was prepared. This slurry liquid was poured into a mold, allowed to react and solidify in a hot water bath for 24 hours, then washed with water to remove excess acid, aldehyde and corn starch, and dried. After drying, water-soluble acrylic resin (Aron:
(Toa Gosei Co., Ltd.) and dried again. Thereafter, heat treatment was performed at a temperature of 250 ° C. for 24 hours to obtain six types of grinding wheels shown in Table 1.

The grindstone thus obtained was fixed to a metal mounting plate of a lapping machine VSP-9B manufactured by Fujikoshi Machinery Co., Ltd., and an aluminum substrate (3.5 inches) was polished. Water is used as the polishing liquid, and 10 pieces are polished at one time, and after polishing for 3 minutes, the surface condition (surface accuracy) of the aluminum substrate is inspected with a universal surface shape measuring instrument SE-3H manufactured by Kosaka Laboratory, and The polishing rate and the presence or absence of scratches were examined.

Further, in order to confirm the clogging state of the grindstone surface and the like, the grindstone was continuously polished 50 times without dressing (dressing) work.
The presence or absence of scratches was inspected, and the state of clogging of the grindstone surface was inspected. The results are also shown in Table 1.

[0018]

[Table 1]

From the results shown in Table 1, it can be seen that a grindstone using a specific amount of an acrylic resin and a phenolic resin in combination has good surface accuracy, does not cause scratching, and does not cause clogging.

[0020]

As described above, the grinding wheel for soft metal of the present invention has a good finished surface accuracy, does not cause scratches, hardly causes clogging of the grinding wheel surface, and can improve the polishing efficiency. You can do it.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B24D 3/02 B24D 3/28

Claims (1)

(57) [Claims] (A) polyvinyl acetal resin
20 to 28% by weight, (B) 50 to 70% by weight of abrasive particles, (C) 5 to 19% by weight of phenolic resin, and (D) 1 to 15% by weight of acrylic resin. Soft metal whetstone.