JPH0624701B2 - Rotary whetstone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention has a moderate rigidity and flexibility in which abrasive grains are uniformly dispersed and incorporated in a homogeneous layer of a biphenyltetracarboxylic acid-based aromatic polyimide. A specific abrasive grain-containing sheet body also has a rotating grindstone (including a dicing saw) composed of a disc-shaped disc body cut out in a disc shape,
The present invention relates to a disk type rotary grindstone in which the disk-shaped disc body is fixed (fixed) to a rotation support base.

The rotating grindstone of the present invention is attached to various polishing or grinding machines, is rotated, and is brought into contact with the surface of the material to be polished and the rotating flat surface or the peripheral portion of the rotating grindstone, or, Used for finely grinding or grooving various kinds of inorganic materials (such as silicon wafers) or metal materials, or for precisely cutting inorganic materials at the peripheral edge of the rotating grindstone. Is something that can be done.

[Description of Prior Art]

A flexible polishing sheet such as a paper file is known in which abrasive grains for polishing are applied together with an adhesive or the like on the surface of a base material made of paper, etc. Due to the material and adhesive of the base material of the above, it does not have sufficient mechanical strength, heat resistance and polishing performance, and is an industrial rotary grindstone that is hard and difficult to polish or cut. It could not be used for polishing or cutting.

Further, as a heat-resistant grinding material for cemented carbide, aromatic polyimide powder (abrasive grain binder) obtained from pyromellitic dianhydride and aromatic diamine, and abrasive grains such as diamond are used. The mixed powder mixture is filled in a mold, the filling is molded at high temperature and high pressure to produce a thick annular abrasive grain molded body, and this abrasive grain molded body is ground on a wheel-shaped grindstone base. A "grinding tool capable of rotating grinding" manufactured by joining as a grain layer is US Pat. No. 338568.
No. 4, U.S. Pat. No. 3,650,715 and the like.

However, in the powder molding method in the above-described method for producing a heat-resistant grinding material, it was not possible to industrially easily produce a heat-resistant abrasive sheet having a small thickness, rigidity and flexibility.

Furthermore, as a rotary grindstone used for applications such as precise cutting of various base materials, granular or powdery abrasives (hereinafter also referred to as abrasive grains) such as diamond and corundum, metal bonds, resin bonds, etc. It has been known that after being fixedly molded into a thin plate or sheet using the above binder, the molded product is lapped to be thinned to a predetermined thickness and manufactured.

However, the rotary grindstone manufactured by this known method requires a difficult process such as lapping and has low productivity, and the obtained rotary grindstone has variations in the dispersion state of the abrasive grains and variations in the finished thickness. However, it has the drawback that it cannot be used for precise cutting, grooving, etc. Furthermore, the manufacturing cost of the above-mentioned rotary grindstone increases,
There is a problem that the manufacturing cost becomes high.

[Requirements of the present invention and operational effects thereof]

The present inventors have conducted extensive studies for the purpose of providing a rotary grindstone in which various problems that the above-described known rotary grindstone has had been solved, and as a result, organic particles in which the abrasive grains are uniformly dispersed. Made by a solution casting method from a solution of a polymer (such as a solution of aromatic polyamic acid) prepared by polymerizing an aromatic tetracarboxylic acid component of a biphenyltetracarboxylic acid and an aromatic diamine component in a solvent (dispersion liquid). Film-formed "abrasive grain-containing thin film or sheet consisting of a uniform layer of aromatic polyimide containing abrasive grains uniformly dispersed therein and abrasive grains uniformly dispersed in the uniform layer of polyimide (hereinafter ,
Abrasive grain-containing sheet body) "is cut into a disc shape to produce a rotary grindstone made of a disc-shaped disc body, and if necessary, the disc-shaped disc body is fixed to a rotary support pedestal. However, they have found that the above-mentioned various problems can be solved, and completed the present invention.

That is, according to the present invention, abrasive grains having an average particle diameter of 0.1 to 60 μm are uniformly dispersed in a homogeneous layer of a biphenyltetracarboxylic aromatic polyimide at a compounding ratio of 5 to 80% by volume. The present invention relates to a rotary grindstone including a disk-shaped disc body in which a sheet body containing abrasive grains of 10 to 500 μm is cut out in a disc shape, and particularly to a disc-shaped rotary grindstone in which the disc-shaped disc body is fixed to a rotary support pedestal.

The rotating grindstone of the present invention has a biphenyltetracarboxylic acid-based aromatic polyimide containing abrasive grains that are uniformly dispersed therein, and has excellent abrasive grain retention, and also has a mechanical strength. (In particular, tensile modulus, MIT folding strength, etc.), heat resistance (heat loss rate when heated to 500 ° C.), humidity resistance (equilibrium moisture absorption at 25 ° C. at 50% humidity),
Since it is also excellent in chemical resistance, it can exhibit excellent rotary polishing performance, rotary cutability, etc. in terms of heat resistant polishing at high temperatures, long-term durability, chemical resistance to various polishing liquids, etc. A rotary grindstone composed of a disk-shaped disc body in which a novel grindstone-containing sheet body having appropriate rigidity and flexibility is cut out into a disc shape, and particularly a rotary grindstone composed of the disc-shaped disk body and a rotary support base. Is.

The rotary whetstone of the present invention is roughly, from a polyphenylamic acid (polyimide precursor) solution of a biphenyltetracaponic acid system containing abrasive grains uniformly dispersed, a film is formed by a solution casting method or the like, with an aromatic polyimide. After manufacturing an abrasive grain-containing sheet body consisting of abrasive grains, a simple process in which the abrasive grain-containing sheet body is cut into a disc shape to form a disc-shaped disc body, or the disc-shaped disc body is rotated. It is possible to manufacture a uniform and excellent disk-type rotary grindstone by a simple process of fixing to a support pedestal.

[Detailed description of each requirement of the present invention]

Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a perspective view of a rotary grindstone of the present invention, and FIGS. 2 and 3 are a plan view and a sectional view of the rotary grindstone.

According to the present invention, an abrasive grain-containing sheet body 1 having a thickness of about 10 to 500 μm, in which abrasive grains are uniformly dispersed and incorporated in a homogeneous layer of a biphenyltetracarboxylic aromatic polyimide at a specific blending ratio, A rotary grindstone composed of a disk-shaped disk body which is cut out (cut) into a disk shape, particularly a donut disk shape. In particular, as shown in FIG. 3, the disk-shaped disk body 1 is a rotary support pedestal 2 In addition, a rotary grindstone fixed or fixed by an appropriate means (eg, adhesive, screw, etc.), capable of polishing, grinding, and cutting an object to be ground or an object to be ground by high-speed rotation. It is 3.

The abrasive grain-containing sheet body forming the disc-shaped disc body 1 in the present invention contains 5 to 80% by volume, preferably 10 to 70% by volume, and more preferably abrasive grains having an average particle diameter of 0.1 to 60 μm. It is evenly dispersed in a homogeneous system of biphenyltetracarboxylic aromatic polyimide in a blending ratio of 15 to 60% by volume, and has a thickness of 10 to 500 μm, preferably 30 to 400 μm, and more preferably 50 to 300 μm.
Any abrasive grain-containing sheet body may be used.

The disc-shaped disc body 1 is preferably in the shape of a donut disc, and the outer diameter thereof is preferably about 5 to 25 cm, particularly about 6 to 20 cm.

As the abrasive grains uniformly dispersed in the homogeneous layer of the aromatic polyimide in the disc-shaped disc body 1, polishing or grinding having an average particle diameter of 0.1 to 60 μm, preferably about 0.5 to 50 μm. If it is abrasive grain for use,
The maximum diameter of the abrasive grains is about 170 μm or less, especially 150 μm
It is preferably m or less, and examples thereof include abrasive grains having an average particle diameter of natural or artificial diamond, silicon carbide, cubic boronite (boron nitride), fused alumina, spinel, garnet, silica sand, or the like. You can

The abrasive grains may be abrasive grains in which an inorganic or metallic substance is coated on each surface of the abrasive grains.

The aromatic polyimide used in the disc-shaped sheet body 1 is 2,3,3 ′, 4′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, or those acids. An "aromatic tetracarboxylic acid component" mainly containing "biphenyltetracarboxylic acid or its acid dianhydride" selected from the group consisting of dianhydrides (particularly preferably about 60 mol% or more), and 4,4'-
Diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl thioether, 4,4'-diaminodiphenyl sulfone, 4,
4'-diaminobenzophenone, 4,4'-diaminodiphenylmethane, 2,2-bis (4-aminophenyl)
About 50 aromatic diamine compounds selected from the group consisting of propane, o-, m- or p-phenylenediamine and the like.
It is a biphenyltetracarboxylic acid-based heat-resistant aromatic polyimide obtained by polymerizing and imidizing equimolar amounts of both components from the "aromatic diamine component" containing at least mol%.

The aromatic polyimide has a logarithmic viscosity (measured at 50 ° C.,
Concentration: 0.5 g / 100 m solvent, solvent: parachlorophenol) is preferably about 0.1 to 7, particularly about 0.3 to 5.

In the present invention, the above-mentioned aromatic polyimide has a “heat resistance” of 450 ° C. or higher, which is represented by the temperature until 5% by weight of the sample is reduced by heating when the sample is heated at 10 ° C./min.
Particularly, those having a temperature of 500 ° C. or higher are preferable, and the equilibrium moisture absorption rate (which is a moisture absorption rate which is reached by maintaining the environmental conditions of humidity 50% and temperature 50 ° C.) is 1.2% or less, particularly 1.0
% Or less is preferable in terms of durability (heat resistance, retention of mechanical properties, etc.) after being molded into a rotary grindstone.

In the present invention, in particular, about 3,3 ', 4,4'-biphenyltetracarboxylic acid or its acid dianhydride is added to about 70%.
Mol% or more, particularly preferably 80 mol% or more, more preferably 90 to 100 mol% of "aromatic tetracarboxylic acid component" and 4,4'-diaminodiphenyl ether are about 60 mol% or more, particularly preferably 70 mol% or more. A high-molecular-weight aromatic polyimide obtained by polymerizing a "aromatic diamine component" containing at least mol%, more preferably 80 to 100 mol%, in approximately equimolar amounts and further imidizing,
In addition to the above-mentioned heat resistance, durability, mechanical properties, etc., it is suitable for the retention of abrasive grains, that is, the long-term retention of the polishing properties of rotary abrasive grains.

Particularly, 3,3 ', 4,4'-biphenyltetracarboxylic acid or its acid dianhydride is about 60 mol% or more, particularly preferably 70 mol% or more, and further preferably 80 to
An aromatic tetracarboxylic acid component containing 100 mol%,
An aromatic diamine component containing o-, m- or p-phenylenediamine in an amount of about 40 mol% or more, particularly preferably 50 mol% or more, and further preferably 60 to 100 mol% is used in about equimolar amounts, polymerization and imide. The high-molecular-weight aromatic polyimide obtained by liquefaction has particularly high heat resistance, high elastic modulus, and good thermal dimensional stability along with the above-mentioned durability and mechanical properties (from room temperature to 300 ° C). Coefficient of thermal expansion of 4.5 × 10 ^-5 cm / cm / ℃ or less, especially 1.2
Is about 4.0 × 10 ⁻⁵ cm / cm / ° C.), which is preferable.

The aromatic tetracarboxylic acid component may be a mixture of the above-mentioned biphenyltetracarboxylic acid or its acid dianhydride and pyromellitic acid or its acid dianhydride.

In the present invention, in addition to the above abrasive grains and aromatic polyimide, for example, graphite, SiO ₂ , SiC,
A filler made of Al ₂ O ₃ , Fe ₂ O ₃ , Cu, Sn, or a mixture thereof may be blended, and the average particle diameter of the filler is about 0.1 to 100 μm, particularly 0.5.
It is desirable that the powder is about 50 μm.

The abrasive grain-containing sheet body in the present invention is, for example, N-methyl-2-pyrrolidone, N, N-methylformamide, N, N-ethylformamide, N, N-
The above-mentioned abrasive grains are uniformly dispersed in an organic polar solvent such as an amide solvent such as methylacetamide or N, N-ethylacetamide or a phenol solvent such as phenol, cresol or halogenated phenol. While adding and dissolving the aforementioned aromatic diamine component and aromatic tetracarboxylic acid component, 0-80
0.5 to 50 ° C., preferably at a reaction temperature of 0 to 60 ° C.
Reaction (polymerization) of both components for time, preferably 1 to 30 hours
Then, a high molecular weight aromatic polyamic acid (aromatic polyimide precursor) is generated to prepare a solution of the aromatic polyamic acid in which the abrasive particles are uniformly dispersed, and the abrasive particles are dispersed. A liquid thin film is formed on a suitable smooth support by a solution casting method using a polyamic acid solution, and the liquid thin film is dried to remove the solvent and solidify to form a solidified film. , An aromatic polyamic acid is imidized, and further, if necessary, heat-treated at a high temperature of 300 ° C. or higher, whereby the abrasive grains are uniformly dispersed and incorporated in a homogeneous system of the aromatic polyimide and the abrasive. A thin film or a sheet body (abrasive grain-containing sheet body) having a thickness of 10 to 500 μm and composed of grains can be formed.

The abrasive grain-containing sheet body is cut into a disk shape by a known cutting method to produce a disk-shaped disk body.

The dispersion liquid of the abrasive grains is, for example, while stirring the organic polar solvent for polymerization, at a temperature of about 60 ° C. or less, and the abrasive grains in the solvent in a proportion of about 1 to 30% by weight, It can be prepared by adding the abrasive grains and stirring the abrasive grain addition liquid for about 5 to 60 minutes to uniformly disperse the abrasive grains.

In the preparation of this dispersion, if necessary, a suitable coupling agent [eg, α-N-phenylaminopropyl-trimethoxysilane, N-β- (aminoethyl)-
γ-aminopropyl-trimethoxysilane, γ-aminopropyl-trimethoxysilane, vinyl-triethoxysilane, vinyl-tris (2-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyl-
Trimethoxysilane, γ-glycidoxypropyl-methoxysilane, γ-mercaptopropyl-trimethoxysilane, and other trialkoxysilane-based compounds] with respect to the total amount of all monomer components to be added to this dispersion. It is preferable to add it to a solvent together with the abrasive grains in a mixing ratio of about 0.01 to 5% by weight, particularly about 0.05 to 3% by weight, and stir the mixture. The rotary grindstone obtained from the abrasive-containing sheet body produced from the aromatic polyamic acid solution prepared by using is suitable because it has particularly excellent polishing performance.

The aromatic polyamic acid produced in the preparation of the above polyamic acid solution has a logarithmic viscosity (measurement temperature; 30
C, concentration; 0.5 g / 100 m solvent, solvent; N, N-
Dimethylacetamide) is about 0.1-7, especially 0.3-
5, the concentration of polyamic acid in the solution is about 3 to 50% by weight, particularly about 5 to 30% by weight, and the rotational viscosity (25 ° C.) of the solution is about 1 to 5%.
It is preferably about 0000 poise, particularly about 5 to 30,000 poise.

Furthermore, the above-mentioned liquid thin film on the support is about 50 to 150 under normal pressure or reduced pressure, or under the flow of an inert gas.
After heating to ℃ to remove the solvent, it is dried and solidified (coagulated), and after the solidified film is peeled from the support, the solidified film is heated to a temperature of about 200 to 550 ° C. Then, while sufficiently removing the remainder of the solvent in the solidified film, the aromatic polyamic acid is almost completely imidized, and by further heat-treating the solidified film, the abrasive grains are uniformly dispersed in the aromatic polyimide. The built-in "heat-resistant abrasive grain-containing sheet body having appropriate rigidity and flexibility" can be manufactured intermittently or continuously.

Rotation support base 2 that may be used in the present invention
Is a rotary shaft that is connected to the rotary drive device, as long as it has a function of attaching a rotary grindstone and a function of concentrically holding and fixing the disc-shaped disc body 1 so as not to be eccentric during rotation, It may be of any type, size, or any material (for example, thermosetting resin, metal such as aluminum, steel, stainless steel, etc.).

As the rotation support pedestal 2, as shown in FIG.
It is preferable that the disc-shaped disc body is sandwiched from both sides and fixed by an adhesive, screws, or the like.

Further, it is preferable that the rotation support pedestal 2 has its outer diameter appropriately changed according to the outer diameter of the disk-shaped disc body 1.
For example, about 0.1 to 0.8 of the outer diameter of the disk-shaped disc body 1
It is preferable that the outer diameter is about twice, especially about 0.2 to 0.7 times. Further, the rotating grindstone of the present invention, when the disk-shaped disc body is worn, and its outer diameter becomes small,
The rotation support base with a small outer diameter can be replaced for further use.

〔Example〕

Hereinafter, the present invention will be described in more detail by showing examples of the present invention.

Example 1 (Preparation of Aromatic Polyamic Acid Solution) 800 g of N, N-dimethylacetamide was placed in a cylindrical polymerization tank having an inner volume of 2, and 70.64 g of diamond powder (average particle size 5 μ) was stirred while stirring. Then, stirring is continued as it is for about 30 minutes to prepare a dispersion liquid of abrasive grains. Subsequently, 80.99 g of 4,4-diaminodiphenyl ether is added to the dispersion liquid for about 2 minutes, and at 30 ° C. Thirty
The aromatic diamine component is dissolved by stirring for 1 minute, and 107.17 g of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride is gradually added to the obtained solution over 5 minutes. , Stirring the solution at 30 ° C. for 2 hours,
The aromatic tetracarboxylic acid component consisting of the acid dianhydride is dissolved, and both components described above are polymerized, and finally, the polymerization solution is added with 3,3 ′, 4,4′-biphenyltracarboxylic acid dicarboxylic acid. Anhydrous 11.84 g was gradually added, and the mixture was stirred and reacted at 30 ° C. for 3 hours to generate an aromatic polyamic acid, and an aromatic polyamic acid solution in which abrasive grains were uniformly dispersed was prepared.

The aromatic polyamic acid solution has a polymer concentration of 20.
% By weight, and the solution has a rotational viscosity (30 ° C.) of 100.
0 poise, and the logarithmic viscosity of the aromatic polyamic acid in the solution (measurement temperature; 30 ° C., concentration; 0.5 g /
100 m solvent, solvent; N, N-dimethylacetamide) was 1.56.

(Film formation) Using the above-mentioned aromatic polyamic acid solution as a dope solution for film formation, a solution thin film having a uniform thickness is formed on a glass plate by a hand coating method (solution casting method) using an applicator. Then, hot air of about 120 ° C. is supplied to dry the solution thin film to partially remove the solvent to form a solidified film in which about 30 wt% of the solvent remains, and the solidification is performed. The film is peeled from the glass plate, held by a pin tenter, and placed in a heating capable of blowing hot air of about 300 to 450 ° C., and within this heating, the solidified film is dried with the hot air and heat-treated. Then, the solvent contained in the solidified film is removed and the polymer forming the solidified film is completely imidized, and the “abrasive grains having a thickness of 60 μm are uniformly dispersed at a ratio of 12.3% by volume. Built-in aromatic polyimi It was prepared the abrasive sheet "consisting of the film.

With respect to the abrasive grain-containing sheet body, a punching device is used to form a donut-shaped disc-shaped disc body having an inner diameter of 3 cm and an outer diameter of 15 cm, and the disc-shaped disc body is made of a stainless thin plate (disc-shaped, thickness 1 mm, An outer diameter of 8 cm) was concentrically sandwiched and fixed between two pieces to manufacture a rotary grindstone as shown in FIGS.

As a result of testing the polishing performance of this rotary grindstone, it had excellent polishing performance in continuous polishing for a long time of 50 hours or more at a high temperature of 150 ° C.

Further, various physical properties of the abrasive grain-containing sheet body were measured, and various physical properties are shown in Table 1.

Example 2 (Preparation of Aromatic Polyamic Acid Solution) N, N-dimethylacetamide (240 g) was placed in a cylindrical polymerization tank having an inner volume of 1 and, while stirring, 20 g of diamond powder (average particle size 5 μ) and γ- 0.307 g of N-phenylaminopropyl-trimethoxysilane (coupling agent) was added, and as it was, stirring was continued for about 60 minutes to prepare a dispersion liquid of abrasive grains. Subsequently, paraphenylene was added to the dispersion liquid. Diamine 16.
13 g was added in about 2 minutes, the mixture was stirred at 30 ° C. for 30 minutes to dissolve the aromatic diamine component, and the resulting solution was mixed with 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride. 39.49 g of the compound was gradually added over 5 minutes, and the solution was stirred at 30 ° C. for 2 hours to dissolve the aromatic tetracarboxylic acid component consisting of the acid dianhydride and to carry out a polymerization reaction of both components. Then, finally, 4.39 g of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride was gradually added to the polymerization solution, and the mixture was stirred at 30 ° C. for 3 hours to cause reaction, and the aromatic polyamic acid was obtained. An aromatic polyamic acid solution in which an acid was generated and abrasive grains were uniformly dispersed was prepared.

The aromatic polyamic acid solution has a polymer concentration of 20.
% By weight, and the solution has a rotational viscosity (30 ° C.) of 130.
0 poise, and the logarithmic viscosity of the aromatic polyamic acid in the solution (measurement temperature; 30 ° C., concentration; 0.5 g /
The solvent was 100 m, the solvent: NN-dimethylacetamide) was 1.72.

(Film Formation) Film formation was carried out in the same manner as in Example 1 except that the aromatic polyamic acid solution was used as a dope solution for film formation,
"Abrasion grains are uniformly dispersed at a ratio of 12.2% by volume and are made of an aromatic polyimide film and have a thickness of 80μ.
m sheet containing abrasive grains ”was produced.

With respect to the abrasive grain-containing sheet body, a punching device is used to form a donut-shaped disc-shaped disc body having an inner diameter of 3 cm and an outer diameter of 15 cm. The disc-shaped disc body is made of a stainless thin plate (disc-shaped, thickness 1 mm, An outer diameter of 8 cm) was concentrically sandwiched and fixed between two pieces to manufacture a rotary grindstone as shown in FIGS.

As a result of testing the polishing performance of this rotary grindstone, it had excellent polishing performance in continuous polishing at a high temperature of 150 ° C. for a long time of 50 hours or more.

Further, various physical properties of the abrasive grain-containing sheet body were measured, and various physical properties are shown in Table 1.

Comparative Example 1 Example 2 except that no coupling agent was used.
A dispersion liquid of diamond abrasive grains was prepared in the same manner as in.

To the above dispersion liquid, 28.72 g of 4,4-diaminodiphenyl ether was added in about 2 minutes, and the mixture was stirred at 30 ° C. for 30 minutes to dissolve the aromatic diamine component. Acid dianhydride 28.1
5 g was gradually added over 5 minutes, and the solution was stirred at 30 ° C. for 2 hours to dissolve the aromatic tetracarboxylic acid component consisting of the acid dianhydride, and at the same time polymerize both components, Then, the polymerization solution was added with pyromellitic dianhydride 3.1.
3 g was gradually added and reacted by stirring at 30 ° C. for 3 hours to produce an aromatic polyamic acid, and an aromatic polyamic acid solution in which abrasive grains were uniformly dispersed was prepared.

The aromatic polyamic acid solution has a polymer concentration of 20.
% By weight, and the solution has a rotational viscosity (30 ° C.) of 280.
0 poise, and the logarithmic viscosity of the aromatic polyamic acid in the solution (measurement temperature; 30 ° C., concentration; 0.5 g /
100 m solvent, solvent; N, N-dimethylacetamide) was 1.86.

(Film Formation) Film formation was carried out in the same manner as in Example 1 except that the aromatic polyamic acid solution was used as a dope solution for film formation,
"A thickness of 90μ consisting of an aromatic polyimide film in which abrasive grains are uniformly dispersed at a ratio of 12.5% by volume.
m sheet containing abrasive grains ”was produced.

With respect to the abrasive grain-containing sheet body, a punching device is used to form a donut-shaped disc-shaped disc body having an inner diameter of 3 cm and an outer diameter of 15 cm. The disc-shaped disc body is made of a stainless thin plate (disc-shaped, thickness 1 mm, An outer diameter of 8 cm) was concentrically sandwiched and fixed between two pieces to manufacture a rotary grindstone as shown in FIGS.

A polishing test was carried out on the above-mentioned rotary grindstone, and its polishing performance gradually decreased at a high temperature of 150 ° C.
It was not always satisfactory.

Various physical properties of the abrasive grain-containing sheet were measured. Table 1 shows those physical properties.

[Brief description of drawings]

FIG. 1 is a perspective view of a rotary grindstone of the present invention, and FIGS. 2 and 3 are a plan view and a sectional view of the rotary grindstone. 1 ... Disc-shaped disk body, 2 ... Rotating support base, 3 ... Rotating grindstone.

Claims (2)

[Claims] 1. Abrasive particles having an average particle diameter of 0.1 to 60 μm are uniformly dispersed in a homogeneous layer of a biphenyltetracarboxylic aromatic polyimide at a compounding ratio of 5 to 80% by volume, and a thickness of 10 is obtained. A rotary grindstone composed of a disc-shaped disc body in which a sheet body containing abrasive grains of ˜500 μm is cut out into a disc shape. 2. The rotary grindstone according to claim 1, wherein the disk-shaped disk member is fixed to the rotary support base.