JP6924436B2 - Carbon nanotube-coated abrasive grains - Google Patents

Description

The present invention relates to coated abrasive grains having excellent interfacial adhesive strength, which are composited for imparting functionality and improving performance of a particle-dispersed composite material having a resin material as a matrix. More specifically, in order to impart high strength, high thermal conductivity, high electrical conductivity, and wear resistance to the resin material, and to improve the abrasive grain holding force of the abrasive grain processing tool (hereinafter, grindstone). The present invention relates to coated abrasive grains having excellent interfacial adhesive strength to be added.

Abrasive particles generally refer to particles such as diamond and cBN used as cutting edges on a grindstone. However, here, not only the particles used for the grindstone but also the particles used for the particle-dispersed composite material such as structural members are collectively referred to as "abrasive grains".

(Coated abrasive grains)
Generally, in a particle-dispersed composite material in which a large number of abrasive grains are composited with a matrix such as a resin material, in order to exhibit the high strength, high thermal conductivity, high electrical conductivity, and abrasion resistance of the abrasive grains, The interfacial adhesive strength between the abrasive grains and the resin material that is the matrix is important. In order to improve the interfacial adhesive strength, coated abrasive grains in which the surface of the abrasive grains is coated with a certain substance are used.

(Request for coated abrasive grains)
For example, the abrasive grain layer arranged on the processed surface side (surface side) of the resin bond grindstone, which is one form of the grindstone, is a diamond resin composite material in which diamond abrasive grains are composited with the resin material. During processing of the resin bond grindstone, diamond abrasive grains, which are cutting edges, fall off, and the tool life is reached. In recent years, as the demand for processing difficult-to-cut materials has increased, coated diamond abrasive grains with further improved interfacial adhesive strength have been demanded. In particular, in high-reciprocating grinding (a grinding method in which a work table is inverted at high speed), the maximum depth of cut of abrasive grains is large and the processing load on the abrasive grains is large, so that the abrasive grains fall off. ..

(Countermeasures by conventional technology)
Therefore, measures are taken to increase the interfacial adhesive strength between the diamond abrasive grains and the resin material (bonding material in the grindstone) by forming a metal coating on the surface of the diamond abrasive grains. In Patent Document 1, a metal coating such as copper or titanium is formed on the surface of diamond abrasive grains, and measures are taken to increase the interfacial adhesive strength by the anchor effect, which is a physical bonding force, at the interface between the abrasive grains and the resin material. ing. Since the anchor effect increases the interfacial adhesive strength in proportion to the surface area, in Patent Document 2, measures are taken using carbon nanotube-coated diamond abrasive grains in which carbon nanotubes, which are nanomaterials having a large surface area, are arranged on the surface. There is. In Patent Document 3, measures are taken to increase the interfacial adhesive strength by chemically bonding a carbon filler such as carbon nanotubes and a resin material with a copolymer.

(Problems of Patent Documents 1 and 2)
However, in Patent Documents 1 and 2, although the coated diamond abrasive grains having a large surface area can be used to increase the interfacial adhesive strength between the diamond abrasive grains and the resin material by the anchor effect, these methods use the diamond abrasive grains. Since no chemical bond is formed between the resin material and the resin material, the interfacial adhesive strength cannot be sufficiently increased. In Patent Document 2, by coating the surface of the abrasive grains with carbon nanotubes having a diameter of 10 nm or less, the surface area is made larger than that of the metal coating, and a higher anchor effect is brought out as compared with Patent Document 1. However, there is a limitation in increasing the surface area, and there is a problem that the interfacial adhesive strength cannot be further increased. Further, as in Patent Document 1, there is a problem that no chemical bond is formed between the diamond abrasive grains and the resin material.

(Problems of Patent Document 3)
In Patent Document 3, there is a problem that the interfacial adhesive strength cannot be sufficiently obtained because the adhesion between the abrasive grains and the resin material is only a chemical bond using the functional group of the abrasive grains and there is no anchor effect. Further, in the abrasive grains having a small amount of functional groups or the abrasive grains in which it is difficult to modify the functional groups, there is a problem that the amount of functional groups is insufficient and sufficient interfacial adhesive strength cannot be obtained.

JP-A-2007-38337 JP-A-2010-64217 Japanese Unexamined Patent Publication No. 2012-149164

The present invention has been proposed in view of such conventional circumstances. That is, the present invention relates to an interface between abrasive grains and a resin material used for a resin composite material (material having high strength, high thermal conductivity, high electrical conductivity, abrasive grain processing tool for performing abrasive grain processing, abrasive stone, etc.). Carbon nanotube-coated abrasives for improving adhesive strength, improving functionality such as conductivity in composite materials, suppressing reduction in strength of composite materials due to interfacial peeling, and suppressing abrasive grain dropout (improvement of tool life) in grindstones. The purpose is to provide grains.

The outline of the means for solving the problem in the present invention is as follows. (1) The carbon nanotube coating arranged on the surface of the abrasive grains improves the surface area of the abrasive grains, exerts a strong anchoring effect, and enhances the interfacial adhesive strength. (2) By coating carbon nanotubes having a large surface area and easily modifying functional groups, a chemically bonded phase having a large number of reactive functional groups is introduced on the surface of the abrasive grains to increase the interfacial adhesive strength. (3) A chemical bond phase composed of a copolymer having a reactive functional group is arranged on the surface of the carbon nanotube coating so that the type and amount of the functional group can be arbitrarily selected. (4) In the bonding between the abrasive grains and the carbon nanotube coating, a chemical bond phase having a chemical bond having a functional group on the surface of the abrasive grains and a functional group on the surface of the carbon nanotube is arranged.

That is, the present invention employs at least the following configurations and features.
(Aspect 1)
It is a carbon nanotube-coated abrasive grain having a carbon nanotube coating configured so that carbon nanotubes are entangled with each other on the surface of the abrasive grain. The abrasive grain has a functional group X on the surface side, and the carbon nanotube is a surface. A chemically bonded phase CL having a functional group Y on the side and having a chemical bond having the functional group X and the functional group Y as constituent elements exists between the carbon nanotube coating and the abrasive grains. A chemically bonded phase CL'having a functional group Z is present on the outermost surface of the carbon nanotube-coated abrasive grains, and the functional group Z is an oxazoline group, an isocyanate group, an epoxy group, an acid anhydride functional group, a hydroxyl group, a carboxyl group, A carbon nanotube-coated abrasive grain characterized by being one or more functional groups selected from the group consisting of an amino group.

According to the present invention, when the carbon nanotube-coated abrasive grains of the present invention are composited with a resin material such as phenol, the resin enters the nano-sized pores formed by the carbon nanotube coating configured so that the carbon nanotubes are entangled with each other. Expresses a high anchor effect. At the same time, by introducing a large number of reactive functional groups into the carbon nanotube coating, a chemical bond between the carbon nanotube coating and the resin material can be formed. In particular, a chemical bond can be formed by arranging an oxazoline group, an isocyanate group, an epoxy group, an acid anhydride functional group, a hydroxyl group, a carboxyl group, an amino group, etc. with respect to a phenol resin (including a modified phenol resin). .. That is, there is an effect that the interfacial adhesive strength can be further increased because the carbon nanotube coating is bonded by the action of both the anchor effect due to the high surface area and the chemical bond due to a large number of reactive functional groups. As a result, it is possible to improve the functionality such as conductivity of the composite material, suppress the decrease in strength of the composite material due to interfacial peeling, and suppress the falling of abrasive grains in the grindstone (improve the tool life).

For carbon nanotube-coated abrasive grains, the bonding strength between the abrasive grains such as diamond and the carbon nanotube coating is also important, and by having a chemical bond between the abrasive grains and the carbon nanotube coating, the carbon nanotube-coated abrasive grains are strong and integrated. Therefore, the above-mentioned effect can be more reliably exhibited.

According to claim 2, one of the functional group X and the functional group Y is one or more functional groups selected from the group consisting of a hydroxyl group, a carboxyl group and an amino group, and the other is an isocyanate group and an epoxy. An abrasive grain and a carbon nanotube coating due to the presence of a chemical bond between the functional group X and the functional group Y, which is one or more functional groups selected from the group consisting of a group and an acid anhydride functional group. It is possible to increase the interfacial adhesive strength of.

According to claim 3, the functional group X and the functional group Y are one or more functional groups selected from the group consisting of a hydroxyl group, a carboxyl group, an acid anhydride functional group, and a thiol group. In addition, a copolymer A is interposed between the functional group X and the functional group Y, and the chemical bond between the functional group X and the functional group X'of the copolymer A and the functional group Y are co-located. The presence of the chemically bonded phase CL composed of a chemical bond with the functional group Y'of the polymer A makes it possible to increase the interfacial adhesion strength between the abrasive grains and the carbon nanotube coating.

According to claim 4, the functional group Y is one or more functional groups selected from the group consisting of a hydroxyl group, a carboxyl group, an acid anhydride functional group, and a thiol group, and the chemical bond. The phase CL'consists of a copolymer B having the functional group Z and the functional group Y', and a chemical bond between the functional group Y'and the functional group Y, so that a large number of reactive functional groups are applied to the carbon nanotube coating. A group (functional group Z) can be introduced via the copolymer B. Therefore, a large number of optimum reactive functional groups can be provided depending on the type of resin material, and many chemical bonds can be formed between the carbon nanotube-coated abrasive grains and the resin material, thereby increasing the interfacial adhesive strength. Can be done.

According to claims 5 to 8, the following effects can be obtained by using the 2-oxazoline-based monomer (a) as the copolymer A or the copolymer B.
1. 1. By arranging the chemical bond phase CL'consisting of an oxazoline group which is a reactive functional group on the outermost surface of the carbon nanotube-coated abrasive grains, many chemical bonds can be formed between the carbon nanotube-coated abrasive grains and the resin material. Therefore, the interfacial adhesion strength can be increased.
2. By arranging the chemical bond phase CL in which an appropriate amount of oxazoline group is introduced between the carbon nanotube coating and the abrasive grains, many chemical bonds can be formed between the carbon nanotube coating and the abrasive grains, so that the interface Adhesive strength can be increased.

When the carbon nanotube-coated abrasive grains of the present invention are used for a grindstone, the interfacial adhesive strength of the periphery of the abrasive grains with the resin material can be improved, and the abrasive grain holding force can be sufficiently increased. It is possible to prevent the coated abrasive grains from falling off and easily improve the tool life and grinding performance of the grindstone.

It is a figure explaining the cross-sectional structure of the carbon nanotube-coated abrasive grain of this invention. It is a figure explaining the state of the chemical bond phase in the coated abrasive grain of this invention. When (a) the abrasive grains and the carbon nanotube coating are indirectly chemically bonded via the copolymer, (c) the functional group Z is formed. When placed on the surface of carbon nanotube-coated abrasive grains with a copolymer. It is a figure which showed an example of the model of the direct chemical bond of this invention. (A) Before chemical bond, (b) After chemical bond. It is a figure which showed an example of the model of the indirect chemical bond (when a copolymer is used) of this invention. (A) Before chemical bond, (b) After chemical bond. It is a schematic cross-sectional view of the resin bond grindstone using the carbon nanotube-coated abrasive grains which concerns on embodiment of this invention. It is an electron micrograph of carbon nanotube-coated abrasive grains produced using a copolymer. It is a figure which shows the result of the abrasive grain holding force evaluation by the share test about the carbon nanotube-coated abrasive grain which is an actual product, the uncoated abrasive grain which is a comparative product, and the like. It is a figure which shows the result of the abrasive grain holding force evaluation of the carbon nanotube-coated abrasive grains which have different coating amounts. This is a thermal analysis result for estimating the coating amount of carbon nanotube-coated abrasive grains.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 5, but the present invention is not limited to the following specific embodiments. The same reference numerals are used for the same or corresponding members in the drawings.

(Outline of carbon nanotube-coated abrasive grains)
FIG. 1 is a diagram illustrating a cross-sectional structure of the carbon nanotube-coated abrasive grains 4 of the present invention. The carbon nanotube-coated abrasive grains 4 are composed of abrasive grains 6 and a carbon nanotube coating 7, and the abrasive grains 6 and the carbon nanotube coating 7 are adhered by a chemical bond phase CL (chemical bond C) arranged at their interfaces. The surface of the carbon nanotube coating 7 has a chemical bond phase CL'and has a functional group Z that reacts with the resin material. When the carbon nanotube-coated abrasive grains 4 are put into the bond material 5 to form a resin bond grindstone 1, the functional group Z and the functional group of the bond material 5 form a chemical bond together with the anchor effect, and the carbon nanotube coating 7 and the bond material are formed. High interfacial adhesive strength is developed between the 5 and 5. The abrasive grains 6 are preferably diamond abrasive grains, and are preferably abrasive grains in which a large number of functional groups X are previously imparted to the surface thereof by acid treatment, plasma treatment, or the like.

(Outline of chemical bond phase)
FIG. 2 is a diagram illustrating a state of a chemically bonded phase in the coated abrasive grains of the present invention. FIG. 2A is a schematic view in the case where a chemical bond is directly formed without using a copolymer. The abrasive grains 6 have a functional group X on the surface, and the carbon nanotube coating 7 made of carbon nanotubes 8 has a functional group Y on the interface with the abrasive grains 6 side and a functional group Z on the surface side. At the interface between the carbon nanotube coating 7 and the abrasive grains 6, a chemical bond phase CL composed of a chemical bond C having a functional group X and a functional group Y as constituent elements is formed. The functional group Z on the surface side of the carbon nanotube coating is the chemical bond phase CL', and when it is composited with the resin material, it forms a chemical bond with the functional group of the resin material.

FIG. 2B shows a case where the abrasive grains 6 and the carbon nanotube coating 7 are indirectly chemically bonded via a copolymer. The abrasive grains 6 have a functional group X on the surface, and the carbon nanotube coating 7 made of carbon nanotubes 8 has a functional group Y between the abrasive grains 6 and the surface side. A copolymer A is arranged at the interface between the carbon nanotube coating 7 and the abrasive grains 6, and the chemical bond C and the copolymer having the functional group X'of the copolymer A and the functional group X of the abrasive grains 6 as constituent elements. A chemical bond C having a functional group Y'of A and a functional group Y of the carbon nanotube coating 7 as a constituent element exists to form a chemical bond phase CL. On the surface side of the carbon nanotube coating, there is a chemical bond phase CL'with the functional group Z arranged on the outermost surface, and when it is combined with the resin material, it forms a chemical bond with the functional group of the resin material.

FIG. 2C shows a case where the functional group Z is arranged on the surface of the carbon nanotube-coated abrasive grains 4 by a copolymer. The abrasive grains 6 have a functional group X on the surface, and the carbon nanotube coating 7 made of carbon nanotubes 8 has a functional group Y between the abrasive grains 6 and the surface side. A copolymer A is arranged between the carbon nanotube coating 7 and the abrasive grains 6, and a chemical bond C having a functional group X'and a functional group X as constituent elements of the copolymer A and a functional group of the copolymer A are arranged. It forms a chemical bond phase CL composed of a chemical bond C having Y'and a functional group Y as constituent elements. The copolymer B is arranged on the surface of the carbon nanotube coating 7, and is composed of a chemical bond C having a functional group Y'of the copolymer B and a functional group Y on the surface side of the carbon nanotube coating 7 as constituent elements, and is formed on the outermost surface. It forms a chemically bonded phase CL'having a functional group Z. When the functional group Z on the surface side of the copolymer B is composited with the resin material, it forms a chemical bond with the functional group of the resin material.

(Example of carbon nanotube-coated abrasive grains using direct chemical bonds)
FIG. 3 is a diagram showing an example of a model of a direct chemical bond of the present invention. FIG. 3A shows carbon nanotubes 8 and abrasive grains 6 before chemical bonding. An amino group is introduced into the carbon nanotube 8 as a functional group Z and a functional group Y. A carboxyl group is introduced into the abrasive grains 6 as a functional group X. The abrasive grains 6 are immersed in an alcohol solution or the like in which the carbon nanotubes 8 are dispersed and dried. In this step, a chemically bonded phase CL composed of a chemical bond C is formed between the carbon nanotubes 8 and the abrasive grains 6, and the self-aggregating force of the carbon nanotubes is combined to form the carbon nanotube coating 7.

FIG. 3B is a specific example of the state of the chemically bonded phase shown in FIG. 2A, using the carbon nanotube 8 modified with an amino group and the abrasive grain 6 having a carboxyl group introduced therein, and an amino group. This is the state of the carbon nanotube-coated abrasive grains 4 formed by the chemical bonding of the and carboxyl groups. The chemical bond C is an amide bond, and forms a chemical bond phase CL together with unreacted functional groups X and Y, a carboxyl group and an amino group.

The outermost surface of the carbon nanotube-coated abrasive grains 4 is covered with a chemical bond phase CL'consisting of unreacted amino groups. For example, if an epoxy-modified phenol resin is selected as the resin material, it is strong against the epoxy groups of the resin material. Has the ability to form good chemical bonds. When the functional group Z is an amino group, it is effective against an isocyanate-modified phenol resin and an acid anhydride-modified phenol resin in addition to the epoxy-modified phenol resin. When the resin material is a modified resin having an isocyanate group, an epoxy group, or an acid anhydride group, the functional group Z of the carbon nanotube coating 7 may be a hydroxyl group, a carboxyl group, or the like in addition to the amino group. On the other hand, in the case of a non-modified phenol resin, that is, a resin material having a phenolic hydroxyl group, the functional group Z of the carbon nanotube coating 7 is preferably an isocyanate group, an epoxy group, or an acid anhydride group.

(Example of carbon nanotube-coated abrasive grains using indirect chemical bonds)
FIG. 4 is a diagram showing an example of a model of indirect chemical bonds (when a copolymer is used) of the present invention. FIG. 4A shows carbon nanotubes 8, copolymer A, copolymer B, and abrasive grains 6 before chemical bonding. A carboxyl group and a hydroxyl group are introduced into the carbon nanotube 8 as the functional group Y. A carboxyl group and a hydroxyl group are introduced into the abrasive grains 6 as functional groups X. The copolymer A and the copolymer B have an oxazoline group. The abrasive grains 6 are immersed in an alcohol solution or the like in which the carbon nanotubes 8 and the copolymer A and the copolymer B are dispersed, and dried. In this step, a chemically bonded phase CL composed of a chemical bond C is formed between the carbon nanotubes 8 and the abrasive grains 6, and the self-aggregating force of the carbon nanotubes is combined to form the carbon nanotube coating 7.

FIG. 4B is a specific example of the state of the chemically bonded phase CL shown in FIG. 2C. The carbon nanotubes 8 and the abrasive grains 6 modified with a carboxyl group and a hydroxyl group are combined with the copolymer A. This is the state of the carbon nanotube-coated abrasive grains 4 formed by the chemical bond C with the oxazoline group which is the functional group X'of. The chemical bond C is, for example, an amide ester bond formed by cross-linking a carboxyl group and an oxazoline group, and forms a chemical bond phase CL together with the carboxyl group, the hydroxyl group, and the amino group, which are unreacted functional groups X and Y. There is.

The outermost surface of the carbon nanotube-coated abrasive grains 4 is covered with a chemically bonded phase composed of an oxazoline group which is an unreacted functional group Z via a copolymer B. For example, as a resin material, a carboxyl group or a hydroxyl group If a resin having an acid anhydride functional group and a thiol group is selected, it has an ability to form a strong chemical bond with the functional group of the resin material.

(Resin bond grindstone using carbon nanotube-coated abrasive grains)
FIG. 5 is a schematic cross-sectional view of a resin bond grindstone using carbon nanotube-coated abrasive grains according to the embodiment of the present invention. The abrasive grain layer 2 is formed on the surface of the base metal 3 having a disk shape or a small diameter cylinder shape. In the case of a thin grindstone or the like, the base metal 3 is not always necessary, and in the case of the all-blade type resin bond grindstone 1, the base metal 3 is not necessary. The abrasive grain layer 2 is composed of a bond material 5 which is a resin material and carbon nanotube-coated abrasive grains 4. In addition, the bond material 5 may contain metal particles such as copper, silicon carbide particles, and the like. As the abrasive grains 6, when the work material is iron-based, cBN abrasive grains are selected, and when the work material is non-ferrous, diamond abrasive grains are selected.

Examples will be described with reference to FIGS. 6-9. Here, FIG. 6 is an electron micrograph of carbon nanotube-coated abrasive grains produced using a copolymer. FIG. 7 is a diagram showing the results of the abrasive grain holding force evaluation by the share test for the carbon nanotube-coated abrasive grains and the comparative abrasive grains, which are the actual products. FIG. 8 is a diagram showing the results of abrasive grain holding force evaluation of carbon nanotube-coated abrasive grains having different coating amounts. FIG. 9 is a TGA thermogravimetric analysis result for estimating the coating amount of carbon nanotube-coated abrasive grains.

(I) Coated Abrasive Grains According to Examples Carbon nanotubes having oxazoline groups, copolymers having pyrrolidone groups, hydroxyl groups, and carboxyl groups introduced (Nanocyl NC7000, multi-walled carbon nanotubes, diameter about 10 nm, average length 1.5 μm). Was applied to diamond abrasive grains (IRV manufactured by Tomei Diamond, average particle size 50 μm) and dried at 100 ° C. to coat the surface of the diamond abrasive grains with carbon nanotubes. Formed. The coating and drying steps performed once, three times, and five times were used as coated abrasive grains, which were coated once, coated three times, and coated five times, respectively.

(Ii) Observation with an electron microscope When the surface of the coated abrasive grains according to the examples is observed with an electron microscope, it becomes as shown in FIG.
That is, the carbon nanotube coating formed on the surface of the abrasive grains covers the abrasive grains so as to be entangled by the self-cohesive force of the multilayer carbon nanotubes. It can be seen that there are nano-sized pores between the carbon nanotubes, and a sufficient anchoring effect can be expected.

(Iii) Abrasive Grain Retention Test by Share Test The coated abrasive grains SDCNT-CB according to the examples shown in Table 1 and the abrasive grains (SD, SDC, SD-CB, SDCNT-AE) according to the comparative example are of the resole type. Each abrasive grain was fixed to the copper substrate with phenol resin by suspending it in phenol, applying it to a copper substrate by spin coating (3000 rpm, 30 seconds), and drying it at 135 ° C. for 30 minutes. The abrasive grains are in a state of being buried in a phenol resin of about 30% of the abrasive particle size. Abrasive grain holding force evaluation (Tsunehisa SUZUKI, Mutsuto KATO, Hiroshi SAITO and Hiroshi IIZUKA, "Improved Adherence Strength between Diamond Grains and Electrolytic Nickel Bonds by Carbon" Nanotube Coatings ”, Journal of Solid Mechanics and Materials Engineering, Vol. 5, No. 8, pp.386-396 (2011)).

The holding force of each abrasive grain is summarized in FIG. 7. All abrasive grains have an average particle size of 50 μm. SD is uncoated diamond abrasive grains (IRV manufactured by Tomei Diamond), and the interface with the phenol resin has almost no anchor effect or chemical bond. SDC is nickel-coated diamond abrasive grains (IRV-NP manufactured by Tomei Diamond, 55 wt% nickel-coated), and has only an anchor effect and no chemical bond with the phenol resin. SD-CB is a diamond abrasive grain coated only with a copolymer having an oxazoline group, and has only a chemical bond with a phenol resin and has no anchoring effect. SDCNT-AE is a carbon nanotube-coated abrasive grain produced using polyvinylpyrrolidone, and has a strong anchoring effect due to the carbon nanotube coating with a phenol resin, but has no chemical bond. SDCNT-CB is the carbon nanotube-coated abrasive grains of the present invention, and has a strong anchoring effect due to the carbon nanotube coating and a chemical bond due to the oxazoline group with the phenol resin. Both SDCNT-AE and SDCNT-CB were made into abrasive grains coated with carbon nanotubes three times. The abrasive grain holding power of SDC, SD-AE, SDCNT-AE, and SDCNT-CB is 1.26 times, 1.47 times, 1.59 times, and 1.93 times, respectively, as compared with the standard uncoated SD. The value was doubled.

That is, it was found that the abrasive grain holding force of the carbon nanotube-coated abrasive grains in the case of the example was the highest, about 1.93 times on average, as compared with the case of the uncoated abrasive grains. Since there is a significant difference between the abrasive grains with only the anchor effect and the abrasive grains with only the chemical bond, by providing the anchor effect and chemical bond of carbon nanotube coating, when used for a phenolic resin bond grindstone, It was found that the abrasive grain holding power was sufficiently enhanced.

FIG. 8 shows the results of the evaluation of the abrasive grain holding force of the carbon nanotube-coated abrasive grains SDCNT-CB having different coating amounts. The abrasive grain retention of 1-time coating, 3-time coating, and 5-fold coating of SDCNT-CB prepared using a copolymer having an oxazoline group is 1.71 times that of the standard uncoated SD. It was 1.93 times and 1.52 times, and it was found that the abrasive grain holding power of three times coating was the largest.

FIG. 9 is a TGA thermogravimetric analysis result for estimating the coating amount of the carbon nanotube-coated abrasive grains coated three times. The rate of temperature rise in TGA thermal analysis was 10 ° C./min, held at 450 ° C. for 1 hour, held at 500 ° C. for 1 hour, and the temperature was raised to 700 ° C. The weight loss at 450 ° C. and 500 ° C. in the air was the copolymer and the carbon nanotube, respectively, and the carbon nanotube coating amount was estimated from this weight loss. The three-walled carbon nanotube-coated diamond abrasive grains SDCNT-CB showed a decrease of 0.905 wt% at 450 ° C and a decrease of 0.623 wt% at 500 ° C. Table 2 shows the composition ratio of the single-walled, three-walled, and five-walled carbon nanotube-coated diamond abrasive grains SDCNT-CB and the converted thickness of the carbon nanotube coating obtained from the results of TGA thermogravimetric analysis. Here, the diamond abrasive grains are calculated as spheres having a diameter of 50 μm, and the specific densities of carbon nanotubes, copolymers, and diamonds are calculated as 2.1, 1.2, and 3.5. The converted film thicknesses of the carbon nanotube coatings coated once, three times, and five times were 83 nm, 224 nm, and 411 nm, respectively. From FIG. 8, it is known that the carbon nanotube coating is preferably coated three times, so that it can be said that the thickness of the carbon nanotube coating (composite layer of CNT and copolymer) is preferably about 200 nm.

Although the present invention has been described with reference to the above embodiments and examples, the scope of rights included in the present invention is not limited to these embodiments and examples.

According to the present invention, in order to bond the carbon nanotube and the bonding material by both the physical anchoring effect of the carbon nanotube and the chemical bond due to the introduction of the reactive functional group, the abrasive grains of the abrasive grain layer are bonded. Since the holding force can be further increased, it is possible to suppress the falling of the coated abrasive grains during the abrasive grain processing, and to significantly improve the tool life and the abrasive grain processing performance of the resin bond grindstone.

When the carbon nanotube-coated abrasive grains of the present invention are used in a resin bond abrasive, a direct chemical bond between the functional group of the carbon nanotube coating and the reactive functional group of the bond material, or an indirect chemical bond via a copolymer is used. Since the carbon nanotube coating and the bonding material can be firmly adhered to each other, there is an effect that a high abrasive grain holding force, which cannot be obtained only by the physical anchor effect, can be exhibited.

As described above, the present invention has very high industrial applicability and industrial applicability.

1 Resin bond grindstone 2 Abrasive grain layer 3 Base metal 4 Coated abrasive grains 5 Bond material (resin material)
6 Abrasive grains 7 Carbon nanotube (CNT) coating 8 Carbon nanotube (CNT)
A copolymer A
B copolymer B
C Chemical bond CL Chemical bond phase with chemical bond with functional group X and functional group Y as constituents CL'Chemical bond phase with reactive functional group Z X Functional group provided on the surface side of abrasive grains X'abrasive grains Functional group Y attached to the copolymer A, which is associated with the functional group X of the functional group Y ′ provided on the surface side of the carbon nanotube A reactive functional group located on the outermost surface of the grain, which is a functional group associated with the chemically bonded phase.

Claims (6)

It is a carbon nanotube-coated abrasive grain having a carbon nanotube coating configured so that carbon nanotubes are entangled on the surface of the abrasive grain.
The abrasive grains have a functional group X on the surface side and have a functional group X.
The carbon nanotube has a functional group Y on the surface side and has a functional group Y.
The chemical bond phase CL having a chemical bond containing the functional group X and the functional group Y as components is
It exists between the carbon nanotube coating and the abrasive grains and
A chemical bond phase CL'having a functional group Z is present on the outermost surface of the carbon nanotube-coated abrasive grains.
The functional group Z is, oxazoline group, isocyanate group, an epoxy group, an acid anhydride functional group, Ri hydroxyl group, a carboxyl group, an amino group, one or more functional groups der selected from the group consisting of,
The functional group X and the functional group Y are one or more functional groups selected from the group consisting of a hydroxyl group, a carboxyl group, an acid anhydride functional group, and a thiol group, and the functional group X. A copolymer A is interposed between the functional group Y and the functional group Y, and the chemical bond phase CL is coexisting with the chemical bond between the functional group X and the functional group X'of the copolymer A and the functional group Y. Consists of a chemical bond of the polymer A with the functional group Y',
The copolymer A is carbon nanotubes coated abrasive grains, wherein the copolymer der Rukoto containing 2-oxazoline monomer (a) as essential structural units. The functional group Y is one or more functional groups selected from the group consisting of a hydroxyl group, a carboxyl group, an acid anhydride functional group, and a thiol group.
The claim is characterized in that the chemical bond phase CL'composed of a copolymer B having the functional group Z and the functional group Y', and a chemical bond between the functional group Y'and the functional group Y. carbon nanotubes coated abrasive according to 1. Before SL copolymer B is carbon nanotubes coated abrasive according to claim 2, characterized in that a copolymer containing 2-oxazoline monomer (a) as essential structural units. At least one of the copolymer A and the copolymer B is a copolymer containing a 2-oxazoline-based monomer (a) and a nitrogen-containing heterocyclic monomer (b) as constituent units, and is a copolymer.
The carbon nanotube according to claim 2 or 3 , wherein at least one of the copolymer A and the copolymer B contains 1 to 90 mol% of the 2-oxazoline-based monomer (a). Coated abrasive grains. The functional group X'and the functional group Y'of the copolymer A are oxazoline groups, and the chemical bond between the oxazoline group and the functional group X and the chemistry of the oxazoline group and the functional group Y. The carbon nanotube-coated abrasive grains according to any one of claims 1 to 4 , wherein a bond is present. The functional group Y'of the copolymer B is an oxazoline group, and any of claims 2 to 5 , wherein a chemical bond between the oxazoline group and the functional group Y is present. Carbon nanotube-coated abrasive grains.

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