JP2003205466A - Super abrasive grain wheel and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a super abrasive grain wheel having both characteristics of resin bond and vitrified bond and having superior abrasion resistance and cutting performance in particular and to provide its manufacturing method. <P>SOLUTION: This super abrasive grain wheel is provided with an abrasive grain layer formed by retaining super abrasive grains by binder. This wheel is characterized in that the binder is mixture between (A) Polybenzimidazole resin and (B) glass of a softening point of 650°C or less, which is measured by a test method stipulated in JIS R 3104-1970, the powdered bodies of the binder, the super abrasive grains, and powdered mixture containing filler as necessary are molded at 500-650°C, and the abrasive grain layer is provided in a using part of a base metal. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a superabrasive wheel and a method for manufacturing the same. More specifically, the present invention provides
Both polybenzimidazole-based resin and glass are involved in bonding as a bonding agent, combine the properties of both resin bond and vitrified bond, and especially superabrasive wheel with excellent wear resistance and sharpness, and efficiently manufacture this It is about how to do it.

[0002]

Superabrasive wheels using diamond, cBN (cubic boron nitride) or the like are widely used for grinding metals, ceramics, glass, plastics, rubber, composite materials and the like. Superabrasive wheels can be generally classified according to the type of binder in the abrasive layer portion,
For example, resinoid binder (Resinoid bon)
Resin bond wheel using d), metal binder (M
metal bond wheel using an (etal bond),
Vitrified bond
There is a vitrified bond wheel using d). Among these, the metal-bonded superabrasive wheel has excellent abrasive grain retention and wear resistance, but poor sharpness. Vitrified bond superabrasive wheels generally have good sharpness and good wear resistance, but have the drawback of being brittle and easily chipped. On the other hand, the resin bond superabrasive wheel is
It has features such as easy molding, suitable hardness, excellent impact resistance, and relatively little heat generation. Depending on the type of binder, wet grinding, dry grinding, heavy grinding, etc. It is used in a wide range from rough grinding to precision grinding, from soft metal to hard hardened steel. In particular, a resin-bonded superabrasive wheel is generally used for the grinding of hard and brittle fractures such as cemented carbide, cermet, ceramics and glass. The reason is that the resinoid binder has a relatively small compressive elastic modulus and is liable to undergo elastic deformation to some extent.
This is because there is little biting during grinding and chipping of the work piece due to grinding is less likely to occur. In such a resin-bonded superabrasive wheel, a thermosetting resin such as a phenol resin or a polyimide resin is mainly used as a resinoid binder in terms of mechanical strength and heat resistance.
However, although resin-bonded superabrasive wheels that use phenolic resin as a binder are used for a wide range of purposes, including sharp and high-hardness materials, metal-bonded superabrasive wheels and vitrified bond superabrasive wheels. It has inferior wear resistance and low grinding ratio. On the other hand, in a resin-bonded superabrasive wheel that uses a polyimide resin as a binder, the polyimide resin has higher heat resistance and mechanical strength than the phenol resin, and therefore, as described above, it is suitable for heavy grinding. It is suitable, but it has poor wettability to superabrasive grains, and the retention of abrasive grains substantially depends only on the mechanical holding force, and the sharpness is inferior to wheels using phenolic resin. . As described above, in the resin-bonded superabrasive wheel so far, the holding force of the abrasive layer is insufficient,
Since the abrasive layer wears a lot, it is difficult to apply it to the process of giving a desired shape to the work material.Moreover, because the abrasive layer wears quickly, the metal bond superabrasive wheel and the vitrified bond superabrasive are The reality is that the processing cost is higher than that of wheels. For the purpose of improving the characteristics of such a resin-bonded superabrasive grain wheel, for example, in a resin-bonded superabrasive grain wheel using a phenol resin, a technique of compounding glass powder as an inorganic filler is known. However, in this case, the glass powder does not melt at the molding temperature of a general phenol resin, and the function as a bond is not sufficiently exhibited in the actual situation. Further, as the amount of the filler is increased, the components that act on the bond are decreased, which makes it difficult to perform the molding, and the holding force of the abrasive grains may be decreased. Therefore, in a resin-bonded superabrasive wheel using a phenol resin, the compounding amount of the inorganic filler is 50 to 60% by volume.
The degree was the limit. Further, when the compounding amount of superabrasive grains is increased, similarly, molding may be difficult or holding force may be reduced. On the other hand, the vitrified bond superabrasive wheel using glass is excellent in abrasion resistance and has a long life as described above, but has a drawback that it is inferior in rigidity.

[0003]

Under the above circumstances, the present invention is such that both resin and glass are involved in bonding as a bonding agent and has the characteristics of both resin bond and vitrified bond, and particularly The purpose of the present invention is to provide a superabrasive wheel having excellent wear properties and sharpness.

[0004]

Means for Solving the Problems As a result of intensive studies to develop a superabrasive grain wheel having the above-mentioned excellent function, the present inventors have found that polybenzimidazole resin has excellent dimensional stability. In addition to having mechanical strength and super heat resistance, it is a thermoplastic resin, unlike phenolic resin or polyimide resin, so it has good wettability to superabrasive grains and has excellent abrasive grain holding power, and as a binder , It was found that the object can be achieved by using a mixture of this polybenzimidazole-based resin and glass having a softening point not higher than a certain temperature, and the present invention has been completed based on this finding. . That is, the present invention provides (1) a superabrasive grain wheel having an abrasive grain layer in which superabrasive grains are held by a binder, wherein the binder is (A) a polybenzimidazole-based resin and (B) JIS. R 3104-1970
Superabrasive wheel, characterized by comprising a mixture with glass having a softening point of 650 ° C. or lower measured by the test method defined in paragraph (2), wherein the binder is a total of component (A) and component (B). 20 to 80% by volume of the component (A) based on the volume,
The superabrasive wheel according to the first aspect, which comprises the component (B) in a proportion of 80 to 20% by volume, and the polybenzimidazole resin (3) represented by the general formula [1].

[Chemical 3] (Ar ¹ in the formula is a tetravalent aromatic residue, Ar ² is a divalent aromatic residue.), And 97
% Abrasive, a superabrasive wheel according to item 1 or 2, wherein the intrinsic viscosity measured at a temperature of 25 ° C. is 0.2 to 1.5 deciliter / g, (4) the general formula [1. ] The structural unit represented by

[Chemical 4] The superabrasive wheel according to the third aspect, which is represented by, and (5) (a) a polybenzimidazole-based resin powder,
(B) A powder mixture containing a binder powder composed of a glass powder having a softening point of 650 ° C. or less measured by a test method defined in JIS R 3104-1970, superabrasive particles, and a filler optionally containing a filler. , A method of manufacturing a superabrasive grain wheel, which comprises molding at a temperature of 500 to 650 ° C. and providing an abrasive grain layer on an operating portion of a base metal.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the superabrasive grain wheel of the present invention, the superabrasive grains are (A) polybenzimidazole resin and (B).
A wheel having an abrasive layer held by a binder made of a mixture with glass and optionally containing a filler. In the superabrasive wheel of the present invention, examples of the superabrasive particles used for the abrasive grain layer include diamond abrasive grains and cBN (cubic boron nitride) abrasive grains. The diamond abrasive grains and the cBN abrasive grains may be used each alone, or may be used as a mixed abrasive grain in which the diamond abrasive grains and the cBN abrasive grains are used in combination. On the other hand, as the polybenzimidazole resin as the component (A) in the binder, one having an intrinsic viscosity measured in a 97% sulfuric acid solvent at a temperature of 25 ° C. in the range of 0.2 to 1.5 deciliter / g is used. It is preferably used. If the intrinsic viscosity is less than 0.2 deciliter / g, the dimensional stability, mechanical strength, heat resistance and the like are insufficient, and a superabrasive grain wheel having desired performance cannot be obtained. Sometimes the purpose cannot be achieved. If the intrinsic viscosity exceeds 1.5 deciliter / g, it is difficult to manufacture and it is not practical. From the viewpoint of the performance of the superabrasive grain wheel and the resin manufacturing aspect, the more preferable range of this intrinsic viscosity is 0.55 to 0.8.
It is 5 deciliters / g. The polybenzimidazole-based resin used in the present invention is not particularly limited as long as the intrinsic viscosity is preferably within the above range, and conventionally known resins can be used. Examples of such a polybenzimidazole resin include those represented by the general formula [1]

[Chemical 5] (Ar ¹ in the formula is a tetravalent aromatic residue and Ar ² is a divalent aromatic residue.). In the above general formula [1], examples of the tetravalent aromatic residue represented by Ar ¹ include diphenyl-3,
3 ', 4,4'-tetrayl group, diphenyl ether-3,
3 ', 4,4'-tetrayl group, benzophenone-3,3',
4,4′-tetrayl group and the like, and examples of the divalent aromatic residue represented by Ar ² include 1,4-phenylene group, 1,3-phenylene group, 2,6-naphthylene group and the like. Is mentioned.

The polybenzimidazole resin may be a homopolymer having one type of structural unit represented by the above general formula [1] or a copolymer having two or more types. . In the present invention, as the polybenzimidazole-based resin, from the viewpoint of the performance of the resulting superabrasive wheel, the formula [2] is particularly preferable.

[Chemical 6] Those having a structural unit represented by are preferred. The polybenzimidazole-based resin having the structural unit represented by the above formula [2] can be produced, for example, by polycondensing 3,3′-diaminobenzidine and diphenyl isophthalate. The polybenzimidazole-based resin having such a structure is, for example, a commercially available product “cerazole (Ce
Lazole) "[registered trademark of Hoechst Celanese Co., Ltd.]. Further, as the glass of the component (B), JI
A material having a softening point of 650 ° C. or lower, which is measured by the test method defined in S R 3104-1970, is used. The preferred softening point of this glass is 400 to 650 ° C, and the more preferred softening point is 500 to 650 ° C. By using the glass having such a softening point, both the above-mentioned polybenzimidazole resin and the glass participate in the bonding as a bonding agent. As such glass, for example, lead glass, phosphate glass, borate glass, silicate glass or the like can be selected. This glass may be used alone or in combination of two or more. In the present invention, the content ratios of the component (A) and the component (B) in the binder are respectively 20 to 80% by volume and 80 to 2 based on their total volume.
The range of 0% by volume is preferable. If this ratio deviates from the above range, it is difficult to obtain a superabrasive grain wheel having both desired resin bond and vitrified bond characteristics, excellent wear resistance, and good sharpness.

In the abrasive grain layer of the superabrasive grain wheel of the present invention, an additive component conventionally used in the abrasive grain layer of a conventional superabrasive grain wheel, if desired, within a range not impairing the object of the present invention,
For example, in addition to the filler, a lubricant and the like can be appropriately contained. Here, as the filler, for example, silicon carbide, boron carbide, carbides such as tungsten carbide, silicon nitride, nitrides such as titanium nitride, silicon oxide, cerium oxide, iron oxide, oxides such as chromium oxide, copper, tungsten. Powders of metals such as nickel, silver, and zinc can be given. These fillers may be used alone or in combination of two or more.
Examples of the lubricant include hexagonal boron nitride, molybdenum disulfide, tungsten disulfide, tantalum disulfide,
Layered solids such as graphite, fluorinated graphite, boron nitride, phthalocyanine, mica, fluorides such as calcium fluoride, sodium fluoride, barium fluoride, lanthanum fluoride, yttrium fluoride, sulfides such as iron sulfide, aluminum oxide Examples thereof include oxides such as molybdenum oxide, tungsten oxide, iron oxide, and silicon oxide, soft metals such as gallium, indium, tin, silver, copper, and gold, and hard metals such as tungsten and molybdenum. Among these, hexagonal boron nitride, molybdenum disulfide, tungsten disulfide, graphite, calcium fluoride and barium fluoride are particularly suitable for use because they have a large lubricating effect. This lubricant is preferably used in the form of fine powder. These lubricants may be used alone or in combination of two or more. The proportion of the superabrasive grains, the binder, the pores and the like in the abrasive grain layer is not particularly limited and can be appropriately selected depending on the purpose of use of the wheel and various other situations.

The shape of the superabrasive grain wheel of the present invention is not particularly limited, and it may be, for example, a cup type superabrasive grain wheel or a straight type superabrasive grain wheel. FIG. 1 is a plan view (a) and a sectional view (b) of a cup-shaped superabrasive wheel, and FIG.
It is a top view (a) and sectional view (b) of a straight type superabrasive grain wheel. In the cup type super abrasive grain wheel, the abrasive grain layer 2 exists on the plane orthogonal to the central axis of the base metal 1, and in the straight type super abrasive grain wheel, the base metal 1
The abrasive grain layer 2 exists on the outer periphery of the. Next, this superabrasive wheel can be manufactured according to the method of the present invention as follows. In the method of the present invention, first, (a) polybenzimidazole-based resin powder and (b) JIS R
A powder mixture containing a binder powder composed of a glass powder having a softening point of 650 ° C. or less measured by a test method defined in 3104-1970, superabrasive particles, and optionally a filler in predetermined proportions. Prepare and then mix this powder mixture with 5
A superabrasive grain wheel is produced by molding at a temperature in the range of 00 to 650 ° C. and providing an abrasive grain layer on the working portion of the base metal. Specifically, the powder mixture is filled in a mold and pressure-fired at a temperature of 500 to 650 ° C. and a pressure of 20 to 200 MPa to form a superabrasive grain layer having a desired shape such as a ring shape. After that, this superabrasive grain layer is adhered to an action portion of an appropriate base metal by an epoxy adhesive or the like to manufacture a superabrasive grain wheel. Alternatively, the powder mixture is placed on the working surface of an appropriate base metal in a mold, and the temperature is 500 to 650.
A super-abrasive wheel is produced by pressure-calcining under conditions of a temperature of 20 to 200 MPa. When the temperature during pressure firing is less than 500 ° C. or the pressure is less than 20 MPa, sufficient pressure firing is not performed, and it is difficult to obtain a superabrasive wheel having desired performance. On the other hand, if the temperature exceeds 650 ° C., the resin may deteriorate, and the pressure of 200 MPa or less is sufficient, and higher pressure is not necessary. Preferred temperature is 500-60
0 ° C., particularly preferred temperature is in the range of 530 to 570 ° C., and preferred pressure is in the range of 40 to 150 MPa. Thus obtained superabrasive wheel of the present invention, both the polybenzimidazole resin and the glass participate in the bond as a bonding agent, have the properties of both resin bond and vitrified bond, wear resistance It is suitable as a superabrasive wheel having excellent wear resistance and sharpness as well as excellent sharpness.

[0009]

EXAMPLES The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 Polybenzimidazole [manufactured by Hoechst Celanese,
Registered trademark "Cerazole U-60", intrinsic viscosity 0.6 deciliter / g, glass transition point 427 ° C] powder 50% by volume
And 50% by volume of glass powder having a softening point of 530 ° C. were mixed to prepare a binder powder. This binder powder has a particle size # 23.
No. 0 Ni coated artificial diamond abrasive grains 4.4 ct / cm
³ (Concentration: 100) A powder mixture was prepared by mixing in an equivalent amount. Next, a base metal is installed in the mold, and the powder mixture is filled in the outer peripheral portion of the base metal, and then the base material is filled with 560 in an air atmosphere.
By holding for 90 minutes under the conditions of ℃ and 60 MPa, hot press sintering, 150D-6T-3X-50.8
I made an H straight wheel. Example 2 A straight wheel was manufactured in the same manner as in Example 1 except that the compounding ratios of the polybenzimidazole powder and the low melting point glass powder were changed to 25% by volume and 75% by volume, respectively. did. Comparative Example 1 A polyimide resin-based resin straight wheel having the same dimensions as in Example 1 and having the same diamond type, particle size, and concentration degree was manufactured. Comparative Example 2 A phenol resin-based resin straight wheel having the same dimensions as in Example 1 and having the same diamond type, particle size, and concentration degree was manufactured. For the straight wheels produced in Examples 1 and 2 and Comparative Examples 1 and 2, using a surface grinder,
A wet traverse grinding test was performed on the cemented carbide under the following conditions to determine the normal grinding resistance and the grinding ratio. The results are shown in Table 1 and also shown in FIG. <Grinding conditions> Testing machine: Horizontal axis surface grinder K manufactured by Okamoto Machine Tool Co., Ltd.
SK-Z1 (3.7KW) Work Material: Cemented Carbide K20 Machining Method: Wet Traverse Grinding Wheel Rotation Speed: 2800min ^-1 Wheel Circumferential Speed: 1540m / min Table Feed: 10m / min Front-rear Feed: 2mm / pass Depth of Cut : 20 μm / pass Total grinding amount: 12 cm ³

[0010]

[Table 1]

Each of the wheels of the examples has significantly lower grinding resistance and excellent sharpness as compared with the polyimide resin type wheel of Comparative Example 1, and has a large grinding ratio and a long life. Further, as compared with the phenol resin wheel of Comparative Example 2, the grinding resistance is low and the sharpness is excellent,
Furthermore, the grinding ratio is significantly high and the life is long.

[0012]

EFFECT OF THE INVENTION According to the present invention, both the polybenzimidazole resin and the glass are involved in the bonding as a bonding agent, and have the characteristics of both resin bond and vitrified bond, and are particularly excellent in abrasion resistance and sharpness. An abrasive wheel is easily obtained.

[Brief description of drawings]

FIG. 1 is a plan view (a) and a sectional view (b) of a cup-shaped superabrasive wheel.

FIG. 2 is a plan view (a) and a sectional view (b) of a straight type superabrasive wheel.

FIG. 3 is a graph showing a relationship between an accumulated grinding amount and a normal grinding resistance in Examples and Comparative Examples.

[Explanation of symbols]

1 unit 2 Superabrasive layer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08K 3/40 C08K 3/40 C08L 79/04 C08L 79/04 A F term (reference) 3C063 AA02 AB03 BB02 BC03 BC05 BC08 BG07 FF08 FF23 FF30 4F071 AA58 AB28 AE13 AE17 DA18 4J002 CM021 DA077 DA087 DA107 DA117 DE097 DE117 DF017 DJ007 DJ017 DK007 DL006 FD017 FD206

Claims (5)

[Claims] 1. A superabrasive wheel having an abrasive grain layer in which superabrasive grains are held by a binder, wherein the binder is (A).
Polybenzimidazole-based resin and (B) JIS R 3
A superabrasive wheel, characterized in that it is made of a mixture with a glass having a softening point of 650 ° C. or lower measured by the test method defined in 104-1970. 2. The binder comprises 20 to 80% by volume of the component (A) based on the total volume of the components (A) and (B).
The superabrasive wheel according to claim 1, which contains the component (B) in a proportion of 80 to 20% by volume. 3. A polybenzimidazole resin is represented by the general formula [1]: (Ar ¹ in the formula is a tetravalent aromatic residue, Ar ² is a divalent aromatic residue.), And 97
% Sulfuric acid solvent having an intrinsic viscosity of 0.2 to 1.5 deciliter / g measured at a temperature of 25 ° C.
Alternatively, the superabrasive wheel described in 2. 4. A structural unit represented by the general formula [1] is represented by the formula [2]: The superabrasive wheel according to claim 3, which is represented by: 5. A binder powder comprising (a) a polybenzimidazole-based resin powder and (b) a glass powder having a softening point of 650 ° C. or less measured by a test method defined in JIS R 3104-1970. And a powder mixture containing superabrasive grains and optionally a filler at a temperature of 500-650 ° C.,
A method of manufacturing a superabrasive wheel, comprising providing an abrasive grain layer on an operating portion of a base metal.