JPS63185580A - Buffing material - Google Patents

Abstract

PURPOSE:To polish a polished article without generating scratch flaws and extremely suppress the consumed quantity of the abrasive grain slurry by dispersing and holding the silicon carbide fine needle-shaped crystals into the fine three-dimensional network structure of a specific porous elastic body. CONSTITUTION:A buffing material is prepared uniformly dispersing and holding the fine needle-shaped silicon carbide crystals in a range of volume mixing rate of 0.5-10% for a buffing basic material into the fine three dimensional network structure of a polyvinyl acetal group porous elastic body. The fine needle-shaped silicon carbide crystal in the buffing material is extremely hard, and the surface of a polished member can be polished without generating scratch flaws. Therefore, the buffing material itself develops the superior polishing force, and the consumed quantity of the abrasive grain slurry supplied from outside can be suppressed to an extremely low value.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a buffing material used for surface polishing of glass, stone, metal, etc.

<Conventional technology> Methods for surface finishing polishing of glass, metal, stone, etc.
BACKGROUND ART Conventionally, so-called buffing materials have been used, which are made by processing wool, goat-based fibers, synthetic fibers, etc. into felt shapes and molding them into disk shapes. Specifically, while rotating the buffing material at high speed, a slurry of fine powder such as cerium oxide, chromium oxide, alumina, or silicon carbide is supplied to the polishing surface as abrasive grains, so that the buffing material scrapes the object to be polished. The method of polishing was extremely intuitive.

<Problems with the prior art> Regarding the felt buffing material mentioned above, it is very difficult to obtain a thickness of 25 mm or more due to manufacturing problems, and the various properties of the felt buffing material include elasticity and diversity. , WQ water resistance, etc. cannot be said to be good, and since the felt buffing material itself has water repellency, the holding power of fine abrasive powder in the buffing channel is not sufficient, and furthermore, the buffing material itself is Since it has no abrasive power, the polishing power is generated only by expensive abrasive slurry input from the outside, which consumes a large amount of abrasive slurry and is disadvantageous in terms of cost. Another drawback has been pointed out: excessive abrasive slurry stains the surrounding area of the grinder with γ9. In addition, if the buffing materials mentioned above are made from natural materials such as wool or goat-based materials, if they are used for a long period of time, undesirable conditions such as rotting mold, bad odor, and discoloration are likely to occur. is extremely unsuitable as a buffing material because it carries the risk of undesirable phenomena such as deterioration of the buffing material. Furthermore, polyvinyl acetal (hereinafter abbreviated as PVAt)
Patent No. 980614 is a buffing material in which finely cut fibers of various types are mixed into a porous elastic material.

No. 980,615 and Japanese Patent Application No. 59-25,612 have been proposed, but although these have excellent retention of fine abrasive powder in the buffing base material, they do not allow for the retention of various types of fibers as contaminants. There is no change in the fact that the finely cut material does not have abrasive power, and as a result, only the abrasive slurry introduced from the outside produces the abrasive power, and it is difficult to say that it is perfect as a buffing material.

<Purpose of the Invention> The present inventors conducted intensive research in view of the above points, and as a result, found that fine acicular crystals of silicon carbide (hereinafter referred to as silicon carbide whiskers) have excellent polishing power, and that It was discovered that the dimensional stability of the buffing material could be supplemented and the present invention was completed. In other words, the objective is to have excellent flexibility, dimensional stability, and compatibility with abrasive slurry, as well as sufficient polishing power and reduce consumption of expensive abrasive slurry. The object of the present invention is to provide a buffing material that can be suppressed as much as possible.

Means for Solving the Problems> The above object is to uniformly disperse and hold fine acicular crystals of silicon carbide in the fine three-dimensional mesh mi3 of a polyvinyl acetal porous elastic body. This is achieved by using the characteristic buffing material.

Specifically, the silicon carbide whiskers used in the present invention are fine needle-like crystals obtained by, for example, causing a gas phase reaction between a carbon component and a silicon component in a high-temperature non-oxidizing gas atmosphere. The fine silicon carbide powder used as abrasive grains is a particulate material obtained by melting an ore mainly composed of silicon carbide and carbon in an electric furnace, and then slowly cooling and growing crystals, which are then crushed and classified. On the other hand, the silicon carbide whiskers have different shapes obtained by completely different methods, and in the case of the silicon carbide whiskers, they can always have a constant diameter by controlling the manufacturing conditions.

Next, the buffing base material mainly composed of the PVAt-based porous elastic body according to the present invention has an average degree of polymerization of 300 to 3 G O (
1. Polyvinyl alcohol with saponification degree of 80% or more 1f=1
The polyvinyl alcohol aqueous solution and an aldehyde as a crosslinking agent are reacted in the presence of an acid catalyst, and then a pore forming agent such as starch is added to make the slurry insoluble in water. Further, silicon carbide whiskers are dispersed and mixed into the dispersion, and the mixture is poured into a predetermined mold and reacted at a temperature of 50 to 80°C for about 5 to 24 hours, and then poured with running water. Surplus aldehydes, #
It is a porous elastic body obtained by removing M, starch, etc., then drying and molding. Starch is commonly used as the above-mentioned pore-forming agent, but it is also possible to mix organic or inorganic fine particles with the starch or use it alone. When fine particles such as asbestos are used as a pore-forming agent, a PVAt-based porous π-elastic material having a network-like three-dimensional continuous pore structure with a finer pore diameter than when starch is used can be obtained.

<Action of the invention> The buffing material according to the present invention will be explained in detail below.

The silicon carbide whisker mixed into the buff according to the present invention is a crystalline substance having a needle-like shape, and has various effects due to the peculiarity of the shape. That is, it is recognized that the individual crystals of the silicon carbide whiskers are extremely small and are extremely hard.

Therefore, during the polishing action, the tip of the needle-shaped crystal body acts well as a scratching tool against the non-abrasive object, and since each crystal is extremely small, the scratching action causes the non-abrasive object to be exposed to a force. There is no risk of leaving marks, etc., and the buff Higuchi et al. exhibits good polishing power, making it possible to minimize or eliminate the consumption of abrasive slurry introduced from the outside.

Further, as described above, since silicon carbide whiskers are needle-shaped crystals, they have a significantly longer overall length than typical silicon carbide granular abrasive grains having the same fiber diameter.

Therefore, the surface area of the silicon carbide whiskers themselves and the adhesion area with the buffing base material are significantly expanded, which naturally improves the retention of the silicon carbide whiskers within the buffing base material, and prevents the silicon carbide whiskers from falling off during the polishing process. The incidence rate will be significantly reduced. Other silicon carbide whiskers mentioned above are
It also has the effect of strengthening the water resistance and dimensional stability within the buffing base material, and also supplements the mechanical strength of the buffing material. That is, since silicon carbide whiskers are minerals and are extremely hard, they have higher dimensional stability than conventional products that use wool or the like as a contaminant. Additionally, if a higher level of water resistance and dimensional stability is required, it is effective to add an appropriate amount of at least one thermosetting resin of phenolic resin, melamine resin, synthetic/poxy resin, and urethane resin. The most preferable addition method is to mix the thermosetting resin into the stock slurry, but it is also possible to impregnate the resin after drying. However, in either case, it is necessary to once raise the temperature to the curing temperature of the added resin and perform curing to reach a chemically stable state.

Next, to explain in detail the effect of the fine three-dimensional cracked structure possessed by the PVAt-based poroelastic body according to the present invention, since pores do not exist independently in this structure and are always a continuous structure,
It works extremely effectively in the polishing action. That is, in the case of an abrasive material such as a buffing material that rubs the object to be polished at high speed rotation, P! ! Frictional heat is likely to occur, and in the worst case, there is a risk that the frictional heat may lead to burning of the buffing material.

Therefore, there is a need for a means to effectively absorb and release the frictional heat to suppress the heating phenomenon of the polishing surface. However, in the case of continuous pores and 1lva as described above, the pore structure absorbs and releases the frictional heat. Since the removal acts as a path, it becomes possible to suppress the phenomenon of high heat generation on the polishing surface. Further, the continuous pore structure described above also enables effective retention of abrasive grains introduced from the outside and effective polishing by the abrasive grains.

Furthermore, when talking about the volumetric mixing ratio when silicon carbide whiskers are mixed into the above-mentioned PVAt-based porous elastic material, it is preferably 0.5 to 10% numerically, and if it is less than this numerical range, the polishing force will decrease. If the amount is insufficient, on the other hand, if the amount is exceeded, the silicon carbide whiskers tend to be poorly dispersed, causing agglomeration of silicon carbide whiskers throughout the buffing chamber, resulting in the worst situation in which the aggregation imparts streaks to the object to be polished.

That is, the state of dispersion of silicon carbide whiskers in the buffing material is an important point that determines the quality of the polishing action, and therefore, great care must be taken when mixing silicon carbide whiskers. Therefore, in normal cases, for example, it is necessary to sufficiently loosen the silicon carbide whiskers before mixing and promote dispersion with a small amount of water or with ultrasonic waves. Polyvinyl alcohol itself, which is the main raw material of
We strive to prevent secondary aggregation in liquids. In addition, if dispersion is insufficient by the conventional method as described above, it is also possible to use a method of adding an appropriate amount of a dispersant such as a surfactant.

<Example> Sample 1 30 g of silicon carbide whiskers of β-type needle-like microcrystal type with a fiber diameter of 0.5 μ and an average total crystal length of 120 μ.

180 g of polyvinyl alcohol with an average degree of polymerization of 1700,
Phenol resin (PR961A manufactured by Sumitomo Bakelite) 2
90 g, formaldehyde as a cross-linking agent, sulfuric acid as a catalyst, and cornstarch as a pore-forming agent to make a uniform slurry, and after casting into a cylindrical mold, excess formaldehyde, acid, and starch were removed. After drying, curing was performed at 13 °C for 6 hours to obtain a disc-shaped buffing material with a diameter of 205 m and a thickness of 25 m. The buffing material thus obtained had a volumetric inclusion rate of silicon carbide whiskers of 11%, an average pore diameter of 120μ, and a porosity of 7.
It was 5%. The buffing material was placed in a polishing machine, and a stainless steel plate was buffed at a rotation speed of 150 OR/M. Note that a mixture of water and polishing oil was used as the polishing liquid, and no abrasive grains were used. The experimental results are used as sample 1.
Shown in the table.

Comparative Example 1 A buffing test was conducted on a stainless steel plate under the same conditions using a buffing material prepared under the same conditions as in Example 1 except that vinylon fibers (cut length 5 m) were mixed in place of silicon carbide whiskers. The experimental results are shown in Table 1 as Comparative Example 1.

Comparative Example 2 A buffing test on a stainless steel plate was conducted under the same conditions as Comparative Example 1, except that a slurry containing 15% of chromium oxide fine powder with an average particle diameter of 0.35 μm was used as the polishing F2 liquid. The experimental results are shown in Table 1 as Comparative Example 2.

Table 1 As is clear from the above table, in the polishing using the conventional buffing material as in Comparative Example 1, there was no polishing effect unless abrasive grains were introduced from the outside. That is, as is clear from the experimental results of Comparative Example 2, the conventional buffing material was able to achieve the same polishing effect as Sample 1 only when abrasive grains were introduced from the outside. However, it was significantly inferior to Sample 1 in terms of finished surface accuracy, etc., and this also showed how good the silicon carbide fine powder mixed in the buffing chamber had a good polishing effect.

<Effects> In the buffing material according to the present invention, silicon carbide whisker itself, which is a contaminant in the buffing company, has abrasive power;
Compared to conventional buffing materials that generate polishing power using only expensive abrasive slurry, it is possible to significantly reduce the consumption of abrasive slurry, resulting in cost reductions.At the same time, the consumption of abrasive slurry As a ripple effect of this reduction, the problem of contamination around the polishing machine is also resolved, making it easier to handle the polishing machine. In addition, since the silicon carbide whisker according to the present invention has an acicular shape, it has superior stability in a buffing company compared to conventional granular abrasive grains, and polishing method using solid abrasive grains such as a solid whetstone. This makes it possible to introduce this into the field of mirror finishing. In addition, there is Felt 4F made of natural fibers, a conventional buffing material using finely cut pieces of various fibers as a buffing material and an admixture, a PVAL porous elastic material as a buffing material, and silicon carbide whiskers as an admixture. When compared with the buffing material according to the present invention, the buffing material according to the present invention has
By using minerals as raw materials for contaminants, it is possible to constantly supply buffing materials of stable quality with little change in physical properties. Furthermore, it is also recognized that the buffing material according to the present invention has a lower incidence of adverse effects such as discoloration, off-odor, and deterioration than buffing materials containing natural products in its composition. Furthermore, the thickness of the finished buffing material does not have the same limitations in manufacturing as in conventional products, and buffing materials having only II can be stably obtained, which has an extremely large effect on the polishing industry. It can be said that there is.

Claims (2)

[Claims] (1) A buffing material characterized by having fine acicular crystals of silicon carbide uniformly dispersed and held in a fine three-dimensional network structure of a polyvinyl acetal porous elastic body. (2) The buffing material according to claim (1), wherein the fine acicular crystals of silicon carbide have a volumetric mixing ratio of 0.5 to 10% with respect to the buffing base material.