JPS6362343B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an abrasive product in which the abrasive grains are bonded with a heat-resistant resin, which is pressure-molded from a specific compound containing at least a specific aromatic polyimide powder and abrasive grains. A grinding tool in which an abrasive grain layer made of a grain molded body and a grindstone substrate made of a cured material formed from a thermoplastic resin composition by heat curing are directly adhered and joined together, especially This invention relates to a novel method for manufacturing a grinding tool in which an abrasive grain layer is provided on a wheel-shaped grindstone substrate. [Description of Prior Art] Conventionally, heat resistant A method for producing an abrasive grain molded body in which diamond or CBN abrasive grains are bonded with a polyimide resin is described, for example, in U.S. Pat. No. 3,385,684 and U.S. Pat. No. 3,650,715.
It is publicly known as described in the specification etc. Currently, the polyimide resins with the best heat resistance used as binders for the abrasive grain moldings include, for example, pyromellitic dianhydride and 4,4-
It is also well known that aromatic polyimides obtained from diaminodiphenyl ether can be used. Further, as a method for manufacturing a grinding tool having an abrasive grain layer made of the abrasive grain molded body on a grindstone base,
First, an abrasive grain molded body in which abrasive grains are bonded with a pyromellitic dianhydride-based aromatic polyimide resin is molded.Meanwhile, a separately molded whetstone base is prepared in advance, and the abrasive grains are There has been known a method of manufacturing a wheel-shaped grinding tool by using a molded body and a grindstone base, and heat-bonding the abrasive grain molded body onto the whetstone base with a suitable heat-resistant adhesive. However, in manufacturing the grinding tool, an expensive and special heat-resistant adhesive that can firmly bond the grinding wheel base and the abrasive grain molded body (abrasive grains and aromatic polyimide bonding material) to each other is used as the adhesive. In addition, since the work of closely adhering and joining the abrasive grain molded body to the whetstone base is generally done at high temperatures, the work is quite difficult depending on the heat resistance and thermal expansion properties of both. Therefore, it is extremely difficult to make the bond between the two sufficiently strong to withstand grinding work, and it has been impossible to industrially manufacture a grinding tool with stable performance with good reproducibility. Furthermore, in the manufacturing of known grinding tools, if the grinding wheel base has a complicated shape, it becomes difficult to fit or fit the abrasive grain molded body onto the grinding wheel base. It may not be possible to manufacture the product. In addition, "a grinding tool having an abrasive grain layer consisting of an abrasive grain molded body in which abrasive grains are bonded with a pyromellitic dianhydride-based aromatic polyimide resin" manufactured by a known method is a The grinding performance is not high enough for heavy grinding, especially the grinding ratio, which is the capacity ratio B/A of the grinding amount B of the material to be polished to the consumption amount A of the abrasive grain layer. It was enough. The inventors aim to industrially easily manufacture a grinding tool with excellent performance consisting of an abrasive grain molded body and a whetstone base, in which abrasive grains are bound together using a highly heat-resistant polyimide resin as a binder. As a result of intensive research on the method, we incorporated an abrasive layer molded body molded using a specific biphenyltetracarboxylic acid-based aromatic polyimide as a binder for the abrasive grains into a mold, and By filling the remaining space in the mold with a thermosetting resin composition and heat-molding it, an abrasive layer consisting of an abrasive grain molded object and a cured product of the thermosetting resin composition are formed all at once. The present invention was completed based on the discovery that it is possible to easily manufacture a grinding tool in which a grinding wheel base is directly and integrally joined. [Structure of the present invention] That is, the present invention comprises 100 parts by weight of abrasive grains, and an aromatic tetracarboxylic acid component and an aromatic diamine component containing 50 mol% or more of biphenyltetracarboxylic acid or its acid dianhydride. 20 to 150 parts by weight of an aromatic polyimide powder obtained by polymerizing and imidizing an aromatic polyimide whose polymer has a second-order transition temperature of 250 to 380° C. The molded abrasive grain body containing 5 to 50% by volume of abrasive grains is incorporated into a mold, and the remaining space in the mold is filled with inorganic or metal powder or the like. The thermosetting resin composition is filled with a thermosetting resin composition containing short fibers, and the thermosetting resin composition is heated and pressurized to form a grindstone base made of a cured product of the resin and a grindstone made of the abrasive grain molded body. The present invention relates to a method for manufacturing a grinding tool characterized by forming a grinding tool in which a grain layer is directly and integrally joined. The second-order transition temperature mentioned above is the second-order transition temperature measured by dynamic viscoelasticity measurement (for example, measured using a mechanical spectrometer manufactured by Rheometrics). [Operations and Effects of the Present Invention] In the grinding tool manufactured by the method of the present invention, in the abrasive grain layer, the above-mentioned biphenyltetracarboxylic acid-based aromatic polyimide used as a binder for the abrasive grains is The heat resistance is expressed as the temperature at which the sample loses 5% by weight by increasing the temperature at 10℃/min.
It exhibits sufficient heat resistance above 530℃ and maintains high mechanical strength even at extremely high temperatures, while also being excellent in formability of the abrasive grain layer and adhesion to the abrasive grain. The performance of the whetstone, such as ratio, is extremely stable and excellent. In the manufacturing method of the present invention, the above-mentioned biphenyltetracarboxylic acid-based aromatic polyimide, which is the binder for the abrasive grain molding, has a relatively low and clear second-order transition temperature, and the abrasive grain molding is heated When the curable resin composition is thermally cured at high temperatures, it can be firmly and integrally bonded to the cured product. By simply filling a thermosetting resin composition and heating and curing the thermosetting resin composition to form a whetstone base, the abrasive grain layer made of the abrasive grain molding and the whetstone base made of the cured product are directly integrated. Grinding tools bonded to each other can be manufactured in one step without using adhesives or the like. Moreover, in the manufacturing method of the present invention, after incorporating the abrasive grain molded body into the mold, a liquid or powder thermosetting resin composition is filled into the mold, hardened and molded, so that the abrasive grain base is It is easy to make the grinding tool into a complicated shape, and it is possible to manufacture grinding tools in various shapes such as wheel shapes. [Example] Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a perspective view showing an example of a grinding tool obtained by the manufacturing method of the present invention, and FIG. 2 is a sectional view of the grinding tool. FIGS. 3 and 4 are cross-sectional views sequentially showing an example of the state of the manufacturing method of the present invention in a mold used in the manufacturing method of the present invention. For example, as shown in FIGS. 1 and 2, the grinding tool obtained by the manufacturing method of the present invention is made of a biphenyltetracarboxylic acid-based aromatic polyimide formed by pressure molding from a specific compound. Abrasive grain layer 1 consisting of an abrasive grain molded body in which grains are combined
This is a grinding tool 3 that is directly and integrally bonded to a grindstone base 2 made of a cured thermosetting resin composition. The aromatic polyimide powder used in this invention is an aromatic tetracarboxylic acid containing biphenyltetracarboxylic acid or its acid dianhydride in an amount of 50 mol% or more, preferably 60 mol% or more, and more preferably 80 to 100 mol%. component and an aromatic diamine component by polymerization and imidization in roughly equimolar amounts, the polymer has a second-order transition temperature of 250 to 380°C, preferably
It is an aromatic polyimide powder with a temperature of 260-350℃. For the aromatic polyimide mentioned above, the sample was heated at 10℃/
The temperature when the sample is reduced by 5% by weight is approximately
Any material may be used as long as it has a heat resistance of 530°C or higher, particularly about 540 to 600°C. The aromatic polyimide described above preferably has a logarithmic viscosity (measured at 50° C., concentration: 0.5 g/100 ml, solvent: parachlorophenol) of about 0.1 to 7, particularly about 0.3 to 5. Furthermore, the average particle size of the aromatic polyimide powder used in this invention is about 0.1 to 100 μm, particularly 0.5 to 100 μm.
The thickness is preferably about 50 μm. The aromatic tetracarboxylic acid component used in the production of the aromatic polyimide is biphenyltetracarboxylic acid or its acid dianhydride,
2,3,3',4'-biphenyltetracarboxylic acid or its acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid or its acid dianhydride, or mixtures thereof. In particular,
3,3',4,4'-biphenyltetracarboxylic acids are preferred, and other aromatic tetracarboxylic acid components that can be used in combination with the biphenyltetracarboxylic acid include pyromellitic acid,
Benzophenonetetracarboxylic acid, bis(3,4
-dicarboxyphenyl)methane, 2,2-bis(3,4-dicarboxyphenyl)propane, bis(3,4-dicarboxyphenyl)ether,
or their acid dianhydrides, or mixtures thereof. Examples of the aromatic diamines include 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylthioether, 4,4'-diaminodiphenylmethane, 3, 4'-diaminodiphenylmethane, 4,
Mention may be made of 4'-diaminodiphenylpropane, 4,4'-diaminobenzophenone, o-, m- or p-phenylenediamine, or mixtures thereof. In this invention, in particular, 3,3',4,4'-biphenyltetracarboxylic acid or its acid dianhydride, or 2,3,3',4'-biphenyltetracarboxylic acid or its acid dianhydride 60 mol% or more, especially 80~
An aromatic tetracarboxylic acid component containing 100 mol%, 4,4'-diaminodiphenyl ether,
A high molecular weight aromatic polyimide powder obtained by polymerizing approximately equimolar amounts of 3,4'-diaminodiphenyl ether with an aromatic diamine component containing about 50 mol% or more, especially 60 to 100 mol%. It is suitable for the moldability of compounds blended with abrasive grains. The abrasive grain molded body used in the production method of the present invention includes 100 parts by weight of abrasive grains, and 20 to 150 parts by weight, preferably 30 to 120 parts by weight, of the above-mentioned aromatic polyimide powder.
In addition, if necessary, 5-50% by volume of abrasive grains may be added by pressure molding from a homogeneously blended powder mixture comprising 0-100 parts by weight, especially 10-80 parts by weight of filler. In particular, any molded abrasive grain containing about 10 to 45% by volume may be sufficient. The aromatic polyimide powder is heated at a temperature of about 50 to 150°C to a temperature of about 0.1 to
It is preferable to use it after drying for about 20 hours, especially about 0.5 to 10 hours. Examples of the abrasive grains include natural or artificial diamond, cubic boron nitride, etc., and the abrasive grains have an average particle size of about 0.5
It is preferably about 1 to 100 μm, particularly about 1 to 100 μm. The filler may be any known filler that is generally used in the production of resin-bonded abrasive molded bodies, such as graphite, SiO ₂ , SiC,
Examples of fillers include Al ₂ O ₃ , FeO ₃ , Cu, Sn, and mixtures thereof, and the average particle size of the filler is preferably about 0.1 to 100 μm, particularly about 0.5 to 50 μm. In this invention, the abrasive grain molded body may contain abrasive grains at a ratio of 5 to 50% by volume, as described above, but in particular, the composition may be abrasive grains: 5 to 50% by volume (particularly preferably 5 to 50% by volume). (10 to 45% by volume), aromatic polyimide resin: 10 to 90% by volume (particularly preferably 20 to 80% by volume), and filler: 0 to 70% by volume (particularly preferably 5 to 50% by weight). It is preferable. Furthermore, it is desirable that the volume ratio between the abrasive grains and the aromatic polyimide resin contained in the abrasive grain layer is within the range of 1:3 to 3:1 (particularly preferably 1:2 to 2:1). . In this invention, the abrasive grain molded body has a shape,
There are no particular limitations on the size, as long as it matches the shape of the abrasive stone base that will be molded later and can be easily incorporated into the mold, but for example, the maximum thickness of the abrasive grain molded body. The length is about 0.1 to 20 mm, especially about 0.5 to 10 mm, and the width (height) is 1 to 500 mm.
mm, especially about 2 to 100 mm, and the outer diameter is 1 mm.
~100cm, especially about 5~50cm, is suitably a toric body, and the physical properties of the abrasive molded body include tensile strength (at 25°C) of approximately 250Kg/cm2 or ^more ;
Further, it is appropriate that the elongation rate at the breaking point is about 1.2 to 5% in order to withstand the high temperature and high pressure during forming of the grindstone substrate. The abrasive grain molded body used in the present invention is obtained by filling a mold with a compound having an appropriate composition containing at least the above-mentioned aromatic polyimide powder and abrasive grains. at a temperature higher than the next transition temperature and at a pressure of 100 to 5000 Kg/ ^cm2 ,
It can be manufactured by forming an abrasive grain molded body in which abrasive grains are firmly bound with an aromatic polyimide binder. In the manufacturing method of the present invention, as shown in FIG. The remaining space of the space 7 formed by the molds 5 and 6 is filled with a fluid thermosetting resin composition containing inorganic or metal powder or their short fibers, and as shown in FIG. While pushing the mold 8 into the space 7 of the molds 5 and 6, the thermosetting resin composition filled in the mold is heated and pressurized under appropriate molding conditions to form the first mold.
As shown in the figure and FIG. 2, a wheel-shaped grinding tool 3 or the like is formed in which a grindstone base 2 made of the cured resin and an abrasive grain layer 1 made of the abrasive grain molded body are directly joined together. That's what I do. Examples of the thermosetting resin composition include:
Powdered or liquid thermosetting resins such as phenolic resin powder, diallyl phthalate resin powder, epoxy resin powder, and phenol aralkyl resin powder, and metal powders such as aluminum, copper, and iron, or carbon graphite. It has sufficient fluidity to fill the mold with other powders such as polyester, silicon, silica, silicon carbide, or short fibers such as metal whiskers, short glass fibers, and short carbon fibers. It is a liquid or powder composition with The thermosetting resin composition has a molding shrinkage rate of about 1.4% by volume or less, particularly 1.0% by volume or less, more preferably about 1.0% by volume or less, when molding the grindstone base by thermosetting.
The composition is such that it is 0.5% by volume or less, and
It is preferable that the transverse rupture strength of the grinding wheel base formed after molding by thermosetting is about 6 Kg/mm ² or more, particularly about 7 to 20 Kg/mm ² . In addition, in the above-mentioned resin composition, the cured product of the thermosetting resin is about 30 to 98% by volume, particularly 40 to 90% by volume, more preferably 50 to 85% by volume in the grindstone base after molding.
It is preferable to have a composition such that the abrasive particles have a composition of % by volume in order to reduce the above-mentioned molding shrinkage rate and maintain adhesion to the abrasive grain molded body. In the manufacturing method of the present invention, the thermosetting resin composition is molded at a temperature of about 100 to 300.
℃, especially preferably about 150 to 250℃,
In addition, the molding pressure should be adjusted to about 10~1000Kg/ ^cm2 , especially 50~1000Kg/cm2.
It is appropriate to set the molding temperature to about 800 kg/cm ² and to set the molding time to about 3 to 60 minutes, especially about 5 to 40 minutes. By the manufacturing method of the present invention, a grinding wheel with an abrasive grain layer provided on a specially shaped grinding wheel base, such as a grinding tool used for polishing a carbide abrasive tool or a high-speed steel tool (see Figs. 1 and 2). (grinding tools as shown)
A wheel-shaped grinding tool with a whetstone base made of a cured product of a thermosetting resin composition that can be used in applications where the abrasive grain layer and part of the whetstone base are worn out during polishing, such as can be easily produced industrially. Hereinafter, the manufacturing method of the grinding tool of the present invention will be explained in more detail using experimental examples. Experimental Example 1 High molecular weight polymer obtained by polymerizing approximately equimolar amounts of 3,3',4,4'-biphenyltetracarboxylic acid or its acid dianhydride and 4,4'-diaminodiphenyl ether. Aromatic polyimide powder (average particle size;
15μm, second order transition temperature; 285℃, 5% weight loss temperature; 575℃, logarithmic viscosity; 3.2, specific gravity after molding:
1.48) 4.62 parts by weight and 140 mesh of nickel-clad synthetic diamond (specific gravity:
5.05) 11.16 parts by weight [artificial diamond (specific gravity:
3.51) containing 4.52 parts by weight] was filled into a predetermined mold and heated at 250°C.
At a temperature ^of
Pressure molding (main molding) was performed at a pressure of Kg/cm ² for 5 minutes to form an annular abrasive grain molded body having the shape shown in FIG. The abrasive grain compact contains 25% by volume of artificial diamond, and is compliant with ASTM D-
1708, the tensile strength is
327Kg/cm ² , and the elongation rate at the break point is 1.8%.
It was hot. This abrasive grain compact is assembled into a mold as shown in Figure 3, and the remaining space of the mold is filled with 75 parts by weight of phenolic resin powder, 15 parts by weight of graphite powder, and 15 parts by weight of aluminum powder. The thermosetting resin composition was filled, and as shown in ^FIG . The shape shown in FIG. 1 is formed by pressure molding for 1 minute, in which the grindstone base made of the cured product of the thermosetting resin composition and the abrasive grain layer made of the abrasive grain molded body are directly joined together. manufactured a grinding tool for the grinding wheel of The grinding tool was subjected to a grinding performance test under the conditions shown below, and the results are shown in Table 1. Grinding wheel shape (dimensions mm) 11V9 (JIS standard) 100 ^b × 30 ^T × 5 ^{u × 3} Grinding wheel circumferential speed V = 1160 m/min Table feed f = 4 m/min Depth of cut t = 0.015 mm Dry grinding (no grinding fluid used) Comparative experiment example 1 Pyromellitic acid-based aromatic polyimide was used as a binder. A grindstone base made of a cured thermosetting resin composition was molded in the same manner as in Experimental Example 1 using an abrasive grain molded body containing artificial diamond in the same proportion as in Example 1, but the abrasive grains The molded body was damaged under high temperature and high pressure molding conditions, making it impossible to manufacture a grinding tool. Comparative Experimental Example 2 Even when using an abrasive grain molded body formed using phenolic resin as an abrasive grain binder, a grinding wheel could not be molded by the same method as in Experimental Example 1, so the gold as shown in Figure 3 was used. Incorporate the already formed whetstone base into the mold, and add a composition in which 4.62 parts by weight of phenolic resin powder and 11.16 parts by weight of artificial diamonds similar to those in Experimental Example 1 were dry blended.
The gap formed between the mold and the whetstone base is filled, and the filling layer in the gap is heated and pressurized to form an abrasive grain layer, and the abrasive grain layer and the whetstone base are integrally joined. manufactured grinding wheels. A grinding performance test of the grinding wheel was conducted in the same manner as in Experimental Example 1, and the results are shown in Table 1. Comparative Experimental Example 3 A grinding wheel was manufactured in the same manner as Comparative Experimental Example 1, except that a composition containing polyamide bismaleimide and artificial diamond in the same composition as Comparative Experimental Example 2 was used. The grinding performance test of the grinding wheel was conducted in the same manner as in Experimental Example 1, and the results were
Shown in the table.

[Table] The grinding tool of Experimental Example 1 shows a grinding ratio superior to any of the comparative experimental examples in carbide grinding.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of a grinding tool obtained by the manufacturing method of the present invention, and FIG. 2 is a sectional view of the grinding tool. FIGS. 3 and 4 are cross-sectional views of molds used in the manufacturing method of the present invention, sequentially showing an example of the state of the manufacturing method of the present invention. 1; Abrasive grain layer, 2; Grinding wheel base, 3; Grinding tool,
4; abrasive molded body, 5; bottom mold, 6; belt mold, 7; space of mold, 8; push mold.

Claims (1)

[Claims] 1. An aroma obtained by polymerizing and imidizing 100 parts by weight of abrasive grains, an aromatic tetracarboxylic acid component containing 50 mol% or more of biphenyltetracarboxylic acid or its acid dianhydride, and an aromatic diamine component. 5 to 50 parts by weight of abrasive grains, which are pressure-molded from a formulation containing at least 20 to 150 parts by weight of an aromatic polyimide powder whose polymer has a secondary transition temperature of 250 to 380°C. The abrasive molded body containing the abrasive grains in the proportion of % by volume is incorporated into the mold, and the remaining space in the mold is further filled with
A thermosetting resin composition containing inorganic or metal powder or short fibers thereof is filled, and the thermosetting resin composition is heated and pressurized to form a grinding wheel base made of a cured product of the resin and the grinding wheel. A method for manufacturing a grinding tool, characterized by forming a grinding tool in which an abrasive grain layer made of a grain compact is directly and integrally joined.