JP2000190236A - Manufacture of abrasive body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the strength of an abrasive layer and a back layer, generate no peeling of the abrasive layer and the back layer when a metallic shaft or a magnetic head is polished, and carry out the removal of the surface unevenness of the metallic shaft, and the surface polishing of the megnetic head without generating a flaw. SOLUTION: This abrasive body is composed by providing an abrasive layer 5 including abrasive grains 3 and a binder 4, on one side surface of a supporting body 2, and a back layer 6 including an inorganic powder 7 and a binder 8, on the surface of the opposite side, and after coating and drying the abrasive layer 5 and the back layer 6, it is heat treated at the temperature and the time to expedite the cross-linking of the binders, to harden and strengthen the abrasive layer and the back layer, so as to improve the durability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to polishing a surface of a metal shaft such as a crankshaft or a camshaft mainly used for an automobile engine or the like.
Also, the present invention relates to a method for manufacturing a polishing body such as a polishing tape and a polishing sheet used for polishing the surface of a magnetic head such as a video head.

[0002]

2. Description of the Related Art For example, in the case of a metal shaft, crater-shaped surface irregularities are generated during a heat treatment process during its production, and the rod-shaped shaft portion is polished to remove the irregularities and flatten the surface. May be applied. Further, in the case of a magnetic head such as a video head, the surface may be shaped and polished to a flat surface so as to maintain input / output characteristics.

For polishing a metal shaft as described above, a polishing tape (polishing body) is wrapped around the rod-shaped shaft portion and, for example, 15 to 25 kgf / cm ^{2 is} applied from the back surface of the polishing tape via a tape holder (pad). The pressing is performed by pressing the rod-shaped shaft portion while pressing the polishing tape, but in this case, if the pressing from the back surface is weak, the polishing becomes insufficient and the rotation of the rod-shaped shaft portion is performed. Accordingly, if the polishing tape is dragged and moved, good polishing cannot be performed. Also, in polishing the magnetic head,
Polishing may be performed with high tension or pressing force.

When the polishing power of the polishing tape is high, the polishing efficiency is improved, but the surface properties of the polished metal shaft or magnetic head are reduced. If the polishing power of the polishing tape is low, the surface properties of the metal shaft or the magnetic head are improved, but the polishing power is insufficient, so that the polishing processing time for obtaining the required surface properties tends to be long. Further, when the polishing tape is used under a strong pressure such as 15 to 25 kgf / cm ^2, a film strength that can withstand the pressure is required.

[0005] As a prior art of these abrasives, Japanese Patent Application Laid-Open Nos. 8-267363, 6-238569, 6-39736, and JP-B-4-40156 are listed.

[0006]

As described above, in the above-mentioned polished body of the prior art, the polishing of the metal shaft does not have a back layer, so that the durability of the polished body as a whole is improved. However, there is a problem that the film strength is insufficient and thus it is not suitable for polishing the metal shaft of the above-described embodiment, or that the polishing layer including the one for polishing the magnetic head has insufficient strength and peels off. are doing.

That is, when the polishing is performed using the above-described polishing body, if the strength of the polishing layer is insufficient and the film is peeled off, the polishing power is reduced, and the crater-like surface unevenness is reduced. Cannot be sufficiently removed and remains in a roughened state, or the surface of the magnetic head cannot be shaped and polished into a predetermined shape. In addition, the peeled polishing layer is sandwiched between the polished portions to act as a trigger, causing scratches on the shaft or the surface of the magnetic head, and the required surface properties cannot be obtained. In the case where the back layer is provided, if the strength is insufficient, the back layer is peeled off, and is dragged by the rotation of the metal shaft, which causes a problem that a required surface property of the shaft surface cannot be obtained.

The present invention has been made in view of the above circumstances, and improves the strength of a polishing layer and a back layer. When a metal shaft or a magnetic head is polished, peeling of the polishing layer and the back layer occurs. An object of the present invention is to provide a polished body which can remove unevenness of the surface of a metal shaft or polish the surface of a magnetic head satisfactorily without causing scratches.

[0009]

According to the method of the present invention for solving the above-mentioned problems, a polishing layer containing abrasive particles and a binder is provided on one surface of a support, and a polishing layer on the opposite side of the support is provided. About providing a back layer containing an inorganic powder and a binder on the surface, a coating solution of the polishing layer and a coating solution of the back layer are coated on a support, and dried to provide the polishing layer and the back layer. The obtained polishing body is heat-treated at a temperature and a time for promoting the crosslinking of the binder, so that the polishing layer and the back layer are cured. This polishing body is suitable for polishing a metal shaft.

[0010] Further, another method for producing a polishing body of the present invention is as follows.
With respect to providing a polishing layer containing abrasive particles and a binder on one surface of the support, a coating solution of the polishing layer is applied on the support, dried to provide the polishing layer, and the obtained polishing body is obtained. Is subjected to a heat treatment at a temperature and for a time to promote the crosslinking of the binder, thereby curing the polishing layer. This polishing body is suitable for polishing a magnetic head.

The heating temperature in the heat treatment of the two polishing bodies is preferably 40 to 100 ° C. (preferably 50 to 80 ° C.), and the processing time is preferably 4 to 72 hours (preferably 12 to 48 hours). . Further, the two polishing bodies may be heat-treated under humidification.

According to the above-described manufacturing method, the crosslinking of the binder in the polishing layer and the back layer is accelerated and cured by heat treatment, so that the film is not sufficiently peeled off when the metal shaft or the magnetic head is polished. This is to give film strength. As for the evaluation of the film strength of the polishing layer, it is desirable that the scratch strength is 300 g or more and that no film peeling occurs during polishing of a metal shaft or polishing of a magnetic head using a polishing machine.

In order to improve the film strength of the polishing layer and the backing layer, for example, the dispersion of a polishing layer coating solution comprising abrasive particles, a binder, an organic solvent and the like in the polishing layer is reduced by using an auxiliary material such as glass beads or steel beads. 30 with mixed
By dispersing for 2 minutes to 2 hours, the dispersibility of the abrasive particles in the binder resin is improved, the adhesion between the abrasive particles is strengthened, and the polishing layer and the heat treatment after the provision of the polishing layer and the back layer are used. It is more preferably realized by curing the binder in the back layer.

In the polishing body having the back layer, the polishing layer has a thickness of 35 to 70 μm, the support has a thickness of 100 to 150 μm, and the back layer has a thickness of 35 to 70 μm.
μm, and the weight ratio of the abrasive particles to the binder in the polishing layer is preferably 100/13 to 100/35. Furthermore, the abrasive particles in the polishing layer have an average particle size of 5 to 50 μm, and preferably 5 to 35 μm.

[0015]

According to the present invention as described above, a coating solution containing abrasive particles and a binder is applied to one surface of a support, dried to form a polishing layer, and then the crosslinking of the binder is promoted. This polishing layer can be hardened by heat treatment at the temperature and time to be applied. For example, in the polishing of a metal shaft or a magnetic head using a polishing machine, the scratch strength of a polishing layer measured by a surface property measuring device is 300 g or more. The film strength can be increased until film peeling does not occur in the practical evaluation, the polishing layer does not drop out during the polishing process, and the polishing power is improved, as a result, the crater-like surface of the shaft surface Able to remove irregularities or form and polish the surface shape of the magnetic head satisfactorily, and at the same time reduce the occurrence of scratch-like scratches on the surface of the object to be polished by the peeling polishing layer, and obtain good surface properties Door can be.

Further, a coating solution containing an inorganic powder and a binder is applied to the surface of the support opposite to the polishing layer, dried and provided with a back layer, and then heat-treated at a temperature and for a time to promote crosslinking of the binder. In this method, the back layer is hardened and the film strength is improved, so that the back layer does not peel off, especially when polishing a metal shaft, the surface roughness can be secured, and the polishing body is prevented from moving due to dragging during polishing. And a curl balance can be obtained. In other words, when the polishing body is pressed against the rod-shaped shaft portion such as a metal shaft from the back surface to perform polishing, in order to prevent the polishing body from being dragged and moved with the rotation of the rod-shaped shaft portion, a certain amount of surface is formed on the back surface. Roughness is necessary, and the back layer contains an inorganic powder for this purpose, ensuring an appropriate surface roughness by the inorganic powder, further improving the film strength, and preventing the back layer from peeling during polishing. I have to.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a method for producing a polishing body of the present invention will be described, and the present invention will be described in more detail. FIG. 1 is a schematic diagram showing a cross-sectional structure of a polishing tape as a polishing body according to the present embodiment.

The polishing tape 1 (polishing body) of the present embodiment has a polishing layer 5 formed on one surface of a support 2 and a back layer 6 laminated on the other surface of the support 2. It is for business.

The polishing layer 5 has an average particle size of 5 to 50 μm.
m, especially 5 to 35 μm of the abrasive 3 is dispersed in the binder 4, and the binder is 13 parts per 100 parts by weight of the abrasive.
３５35 parts by weight. The back layer 6 has an average particle size of 8 μm for obtaining the surface roughness of the back surface.
And a calcium carbonate particle having a large particle size and an average particle diameter of 1 for coloring the back surface to distinguish it from the polished surface.
An inorganic powder 7 composed of iron oxide particles having a small particle size of μm is dispersed in a binder 8. Instead of containing the coloring inorganic powder (pigment), the back layer 6 may be printed on the surface of the back layer 6 so as to be distinguished from the polishing layer.

The support 2 has a thickness of 100 to 150 μm.
m, for example, a polymer support made of polyethylene terephthalate (PET), and the thickness of the polishing layer 5 is 35 to 7
0 μm, the thickness of the back layer 6 is 35 to 70 μm, and the overall thickness is 170 to 290 μm, which is large as the polishing tape 1. Further, the surface of the support 2 is provided with irregularities (not shown) by embossing.

The polishing tape 1 is coated on one surface of a support 2 with a coating liquid for a polishing layer containing abrasive particles 3, a binder 4, a solvent and the like, and an inorganic material is coated on the opposite surface of the support 2. A coating liquid for a back layer containing a powder 7, a binder 8, a solvent and the like is applied and dried to provide a polishing layer 5 and a back layer 6, and then the obtained polishing tape 1 is coated with the binder 4, 8
Temperature (40 to 100 ° C., preferably 5 to 100 ° C.)
0-80 ° C) and time (4-72 hours, preferably 12
To 48 hours), the polishing layer 5 and the back layer 6
To improve the film strength.

The abrasive particles 3 in the polishing layer 5
And a binder 4 and an organic solvent or the like are dispersed for 30 minutes to 2 hours in a state in which auxiliary materials such as glass beads and steel beads are mixed to disperse the abrasive particles in the binder resin. It improves the adhesion between abrasive particles.

The scratching strength of the polishing layer 5 in the polishing tape 1 obtained as described above was measured using a surface property measuring instrument having a stylus tip made of diamond and having a needle diameter of 0.01 mmφ. When the surface of the polishing layer 5 is scratched with a stylus tip under a load, the scratching strength indicated by the load when a scratch reaching the support 2 occurs is 30.
0 g or more.

The portion where the polishing tape 1 is used to polish the crankshaft 10 (metal shaft) of the engine as shown in FIG. 3, for example, is the peripheral surface of the pin portion 10a and the journal portion 10b. A polishing tape 1 having a width corresponding to the length of the portion 10a or the journal portion 10b is prepared.

The polishing method is as shown in FIG.
The polishing tape 1 is fed through a sensor 16 from a feed roll 15 wound in a roll shape.
a, or the polishing tape 1 is wound around the journal portion 10b.
Tape holder 1 provided on swing arms 17, 17 of the book
The polishing tape 1 is pinned from both sides by 8 and 18
Alternatively, the polishing tape 1 is pressed against the journal portion 10b at a pressure of about 15 to 25 kgf / cm ² , and the polished polishing tape 1 is run and wound by the gear 19, the feed roller 20, and the like.

A polishing body for polishing a magnetic head according to another embodiment of the present invention is not shown, but is provided on one surface of a support having the same material and thickness as those used for a magnetic tape. A polishing layer containing abrasive particles and a binder is provided, and the formation of this polished body is performed by applying a coating liquid for a polishing layer containing abrasive particles, a binder, a solvent, and the like on a support in the same manner as described above. After drying and providing the polishing layer, the obtained polished body is subjected to a heat treatment at a temperature and for a time to promote the crosslinking of the binder, thereby curing the polishing layer.

The support which can be used in the abrasive of the present invention includes polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polypropylene, cellulose derivatives such as cellulose triacetate and cellulose diacetate, and polyvinyl chloride and the like. In addition to plastics such as vinyl resins, polycarbonate, polyimide, polyamide, polysulfone, polyphenylsulfone, and polybenzoxazole, metals such as aluminum, paper, and cloth can be used.

Before applying the coating liquid for the polishing layer or the coating liquid for the back layer, the surface of the support is subjected to corona discharge treatment, plasma treatment, undercoat treatment, heat treatment, dust removal treatment, metal deposition treatment, and alkali treatment. You may. The thickness of the support is
100 to 200 μm is desirable for metal shaft polishing, and 4 to 100 μm is desirable for magnetic head polishing.
The Young's modulus in either the longitudinal or width direction is 400 kg
/ Mm ² or more.

The abrasives usable in the polishing layer of the present invention include alumina, chromium oxide, α-alumina, silicon carbide, diamond, γ-alumina, fused alumina, corundum, artificial diamond, garnet and emery ( (Main components: corundum and magnetite), garnet, and other materials having mainly Mohs hardness can be used alone or in combination. The average particle size is 5 to 50 μm, particularly preferably 5 to 35 μm, for metal shaft polishing, and preferably 0.3 to 10 μm for magnetic head polishing. Scratch is likely to occur on the polished part. The average particle size of the abrasive is selected depending on the use of the abrasive body such as rough polishing, medium polishing and finish polishing.

On the other hand, inorganic powders usable for the back layer include particles for obtaining the surface roughness of the back surface, such as calcium carbonate, calcium sulfate, calcium silicate, barium sulfate, magnesium carbonate, zinc carbonate, zinc oxide and the like. Can be used alone or in combination, and as particles (pigments) for coloring the back surface, red-brown iron oxide, yellow lead chromate, titanium yellow, green chromium oxide, blue ultramarine Etc. can be used.

As described above, when the polished surface of the polished body is pressed against the metal shaft (subject to be polished) from the back surface with a tape pressing with a relatively large pressure, if the pressing from the back surface is weak, the polishing is impossible. At this time, if the back surface does not have a sufficient roughness, the abrasive body is dragged by the crankshaft and simultaneously rotates and cannot be polished. The surface roughness Ra of the back surface is about 3μ.
A roughness of about 10 m to 10 m is necessary so that the abrasive body is not dragged by the crankshaft during rotation.

The polishing layer and the back layer may contain a powder having a small particle size in addition to the above-mentioned abrasive or inorganic powder. As the powder, carbon black can be used. Thermal, black for color, acetylene black and the like can be used. Its specific surface area is 5 to 500 m ² / g, DBP oil absorption is 10 to 400 ml / 100 g, pH is 2 to 10,
Moisture content is 0.1-10%, tap density is 0.1-1g /
cm ² is preferred. A specific example of this carbon black is BLACKPEA manufactured by Cabot Corporation.
RLS 2000, 1300, 1000, 900, 80
0,700, manufactured by Mitsubishi Chemical Corporation: 650B, 950B,
3250B, 850, 900, 960, 980, 100
0, 2300, 2400, 2600 and the like. In addition, carbon black that has been subjected to surface treatment with a dispersant or the like or graphitized with a resin can also be used.

As the binder used in the polishing layer and the back layer of the present invention, conventionally known thermoplastic resins, thermosetting resins, reactive resins, electron beam-curable resins, ultraviolet-curable resins, and visible light-curable resins. Resins and mixtures thereof are used.

The thermoplastic resin has a softening temperature of 150.
C. or lower, having an average molecular weight of 10,000 to 300,000 and a degree of polymerization of about 50 to 2,000, more preferably 20 to 2,000.
It is about 0 to 700. For example, vinyl chloride vinyl acetate copolymer, vinyl chloride copolymer, vinyl chloride vinyl acetate vinyl alcohol copolymer, vinyl chloride vinyl alcohol copolymer, vinyl chloride vinylidene copolymer, vinyl acrylonitrile copolymer, acrylic acid Ester acrylonitrile copolymer, acrylate vinylidene chloride copolymer, acrylate styrene copolymer, methacrylate acrylonitrile copolymer,
Methacrylic acid ester vinylidene chloride copolymer, methacrylic acid ester styrene copolymer, urethane elastomer, nylon-silicone resin, nitrocellulose-polyamide resin, polyfucca vinyl, vinylidene chloride acrylonitrile copolymer, butadiene acrylonitrile copolymer, polyamide Resins, polyvinyl butyral, cellulose derivatives (cellulose acetate butyrate, cellulose diacetate, cellulose triacetate, cellulose propionate, nitrocellulose, ethyl cellulose, methyl cellulose, propyl cellulose, methyl ethyl cellulose, carboxymethyl cellulose,
Acetylcellulose), styrene-butadiene copolymer, polyester resin, polycarbonate resin, chlorovinyl ether acrylate copolymer, amino resin, various synthetic rubber-based thermoplastic resins, and mixtures thereof.

The thermosetting resin or the reactive resin has a molecular weight of 200,000 or less in the state of a coating liquid, and becomes infinite by a reaction such as condensation or addition by heating and humidifying after coating and drying. Is preferred. Among these resins, those which do not soften or melt before the resin is thermally decomposed are preferable. Specifically, for example, a phenol resin, a phenoxy resin, an epoxy resin, a polyurethane resin, a polyester resin, a polyurethane polycarbonate resin, a urea resin, a melamine resin, an alkyd resin, a silicone resin, an acrylic reaction resin (an electron beam curing resin), and an epoxy-polyamide Resin, nitrocellulose melamine resin, mixture of high molecular weight polyester resin and isocyanate prepolymer, mixture of methacrylate copolymer and diisocyanate prepolymer, mixture of polyester polyol and polyisocyanate, urea formaldehyde resin, low molecular weight glycol / high molecular weight A diol / triphenylmethane triisocyanate mixture, a polyamine resin, a polyimine resin, and mixtures thereof.

These thermoplastic resins, thermosetting resins, and reactive resins have carboxylic acid (COOM), sulfinic acid (SO ₂ M), sulfenic acid (SOM), sulfonic acid (SOM) as functional groups in addition to the main functional groups. SO ₃ M), phosphoric acid (PO ₄
M ₃ ), phosphonic acid (PO ₃ M ₂ ), sulfuric acid (OSO ₃ M),
And acidic groups such as ester groups thereof (M is H, an alkali metal, an alkaline earth metal, a hydrocarbon group), amino acids;
Aminosulfonic acids, sulfuric acid or phosphoric acid esters of amino alcohols, sulfobetaines, phosphobetaines, amphoteric groups such as alkyl betaines, amino groups, imino groups, imide groups, amide groups, etc., and also a hydroxyl group, an alkoxyl group,
Thiol group, alkylthio group, halogen group (F, Cl,
Br, I), usually containing at least one kind and up to six kinds of silyl groups, siloxane groups, epoxy groups, isocyanato groups, cyano groups, nitrile groups, oxo groups, acrylic groups, and phosphine groups,
Each functional group is 1 × 10 ⁻⁶ eq to 1 × 1 per 1 g of resin.
Preferably, it contains 0 ^-2 eq.

These binders may be used alone or in combination, and other additives may be added. Additives include dispersants, lubricants, antistatic agents, antioxidants, fungicides, coloring agents, solvents and the like.

The polyisocyanate used as a curing agent in the polishing layer and the back layer of the present invention includes tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, naphthylene-1,5-diisocyanate, o -Isocyanates such as toluidine diisocyanate, isophorone diisocyanate, triphenylmethane triisocyanate, and isophorone diisocyanate, products of the isocyanates and polyalcohols, and 2 to 10 formed by condensation of the isocyanates.
It is possible to use a monomeric polyisocyanate, a product of a polyisocyanate and a polyurethane having a terminal functional group of isocyanate, or the like. The average molecular weight of these polyisocyanates is preferably 100 to 20,000.

Commercially available trade names of these polyisocyanates include Coronate L, Coronate HL, Coronate 2030, Coronate 2031, Millionate MR, Millionate MTL (manufactured by Nippon Polyurethane Co., Ltd.),
Takenate D-102, Takenate D-110N, Takenate D-200, Takenate D-202, Takenate 300S, Takenate 500 (manufactured by Takeda Pharmaceutical Co., Ltd.), Sumidur T-80, Sumidur 44S, Sumidur P
F, Sumidule L, Sumidule N, Death module L, Death module IL, Death module N, Death module HL, Death module T65, Death module 1
5, Death module R, Death module RF, Death module SL, Death module Z4273 (manufactured by Sumitomo Bayer), etc., and these are used alone or in combination of two or more utilizing the difference in curing reactivity. be able to.

For the purpose of accelerating the curing reaction, a hydroxyl group (butanediol, hexanediol, having a molecular weight of 100
A compound having an amino group (such as monomethylamine, dimethylamine, or trimethylamine), a metal oxide catalyst, or a catalyst such as iron acetylacetonate can also be used in combination. It is desirable that these compounds having a hydroxyl group or an amino group are polyfunctional. These polyisocyanates are used in an amount of 2 to 7 per 100 parts by weight of the total amount of the binder resin and the polyisocyanate.
0 parts by weight, more preferably 5 parts by weight.
５０50 parts by weight.

As the organic solvent used in the dispersion, kneading and coating of the present invention, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone and tetrahydrofuran in any ratio; methanol, ethanol, propanol and butanol , Isobutyl alcohol, isopropyl alcohol, alcohols such as methylcyclohexanol; methyl acetate,
Ester systems such as ethyl acetate, butyl acetate, isobutyl acetate, isopropyl acetate, ethyl lactate and glycol monoethyl ether; ether systems such as diethyl ether, tetrahydrofuran, glycol dimethyl ether, glycol monoethyl ether and dioxane; benzene, toluene, xylene, Tar-based (aromatic hydrocarbons) such as cresol, chlorobenzene and styrene; chlorinated hydrocarbons such as methylene chloride, ethylene chloride, carbon tetrachloride, chloroform, ethylene chlorohydrin and dichlorobenzene, N, N-dimethylformaldehyde , Hexane and the like can be used. These solvents are generally used in two or more kinds at an arbitrary ratio. In addition, trace amounts of impurities (polymerization of the solvent itself, water,
Raw material components). These solvents are used at 50 to 20,000 parts by weight based on 100 parts by weight of the total solid content of the polishing liquid. The preferred solid content of the polishing layer coating solution is 5
~ 80% by weight.

Representative examples of the water-soluble binder include sodium salt of carboxymethyl cellulose (CMC) and hydroxyethyl cellulose (HE).
Water-soluble binders such as C), polyvinyl alcohol (PVA), and carboxyl group-containing polyurethane can be used. As a solvent for the water-soluble binder, water, a water-soluble alcohol such as methyl alcohol and ethyl alcohol, a mixed solution thereof and the like are used, and various additives are blended as necessary.

Dispersion of the polishing layer component and the back layer component,
The method of kneading is not particularly limited, and the order of addition of each component (resin, powder, lubricant, solvent, and the like), the addition position during dispersion / kneading, and the dispersion temperature (0 to 80 ° C.) are appropriately set. be able to. An ordinary kneader can be used to prepare the polishing layer paint and the back layer paint. As an auxiliary material for the dispersion, glass beads, steel beads, ceramic beads, organic polymer beads or the like having a sphere equivalent diameter of 10 cmφ to 0.05 mmφ are used. These auxiliary materials are not limited to spherical shapes.

As a method of applying the coating liquid for the polishing layer and the coating liquid for the back layer, the viscosity of the coating liquid is adjusted to 1 to 20,000 centistokes (25 ° C.), and then an air doctor coater, a blade coater, and an air knife coater are used. , Squeeze coater, impregnation coater, reverse roll coater, transfer roll coater, gravure coater, kiss coater, cast coater, spray coater, rod coater, forward rotation roll coater, curtain coater, extrusion coater, bar coater, lip coater, etc. Still other methods can also be used, and a specific description of these methods can be found in “Coating Engineering” published by Asakura Shoten (published by Showa 46.3.20), pp. 253-2.
It is described in detail on page 77 and the like. The order of application of these coating liquids can be arbitrarily selected, and a corona discharge treatment or the like may be performed before application of a desired liquid to improve adhesion to an undercoat layer or a support.

After applying the coating liquid for the polishing layer and the coating liquid for the back layer, the polished body is heat-treated in a constant temperature bath at 40 to 100 ° C. for 4 to 72 hours, preferably at 50 to 80 ° C. for 12 to 48 hours. At the time of the heat treatment, it can be humidified using steam. This heat treatment may be performed in a sheet form or after processing into a tape form.

Next, the sheet is cut into a predetermined width to form an abrasive body, and the surface of the abrasive body can be cleaned and burnished if necessary.

[0047]

EXAMPLES Examples and comparative examples of the present invention will be shown below.
As the polishing characteristics, characteristics such as film strength and scratch strength with a polishing machine were evaluated.

<Embodiments 1 to 8> This embodiment has a thickness of 12
A support of 5 μm polyethylene terephthalate (PET) was prepared, and a binder (vinyl chloride copolymer, polyurethane, polyisocyanate), a solvent (a mixed solvent of methyl ethyl ketone and cyclohexanone), an inorganic powder ( A coating liquid for a back layer according to the following formulation, in which calcium carbonate: particle size 8 μm and iron oxide: particle size 1 μm) are dispersed, has a thickness of 4 after drying.
A back layer was formed by applying the solution to a thickness of 0 μm using a blade coater and drying the solution.

Further, a binder (vinyl chloride copolymer, polyurethane, polyisocyanate), a solvent (a mixed solvent of methyl ethyl ketone and cyclohexanone), an abrasive (aluminum oxide: particle size) 30 μm) was placed in a dispersion of steel beads and dispersed for 120 minutes. After the dispersion, the steel beads were separated and removed using a filter to obtain a coating liquid for a polishing layer according to the following formulation. This polishing layer coating liquid was applied by a blade coater so that the thickness after drying became 60 μm, and dried to form a polishing layer.

The polishing sheet prepared as described above was
It was slit into an 8 mm width, and was heat-treated while being held in a constant temperature bath under various heat treatment conditions as shown in Table 1 described below to obtain a polished body for evaluation. This heat treatment was performed in a dry state without using steam.

In Examples 1 to 4, the temperature was changed to 50 to 100 ° C. with the processing time constant (24 hours). In Examples 5 to 8, the processing time was changed to 6 with the temperature constant (70 ° C.). It was changed to ~ 72 hours.

Table 1 shows the film strength, scratching strength, process suitability and overall evaluation of the polishing tapes of Examples 1 to 8 produced as described above, using a polishing machine.

<Comparative Examples 1 to 3> Table 1 also shows the same evaluation results as above using the polishing tapes of Comparative Examples 1 to 3. The basic configuration other than the heat treatment conditions of these comparative examples is the same as that of the above-mentioned Example 1, Comparative Example 1 is an example without heat treatment, Comparative Example 2 is an example with a low heat treatment temperature, and Comparative Example 3 is a heat treatment time. Here is a short example.

[Preparation of Coating Solution for Abrasive Layer] Abrasive (alumina) 600 parts Vinyl chloride copolymer (MR110: manufactured by Zeon Corporation, containing potassium sulfonate) 6 parts Polyurethane (UR8300: manufactured by Toyobo Co., Ltd., sodium sulfonate group) 25 parts Polyisocyanate (Coronate L: manufactured by Nippon Polyurethane) 30 parts Solvent 300 parts [Formulation of back layer coating solution] Calcium carbonate 440 parts Iron oxide 4 parts Vinyl chloride copolymer (MR110: manufactured by Zeon Corporation, sulfonic acid) Potassium salt) 20 parts Polyurethane (UR8300: manufactured by Toyobo Co., Ltd., containing sodium sulfonate group) 40 parts Polyisocyanate (Coronate L: manufactured by Nippon Polyurethane) 50 parts Solvent 420 parts

[0055]

[Table 1]

The evaluation method in Table 1 will be described.

(1) Evaluation method of film strength with polishing machine A small polishing machine was prepared for evaluating a polishing body, and a work piece for evaluation (material: carbon steel cast steel SC material, hardness: HRC55, size) : 40mmφ x 20mm width, oil hole:
13 mmφ), Workpiece rotation: 145 rpm Oscillation: 78 rpm Clamping pressure: 18 kgf / cm ² Polishing time: 12 seconds Cutting oil: Yusilon oil No. 2 (manufactured by Yushiro Chemical Industry Co., Ltd.), polishing the film strength of the polishing layer In the evaluation of, the size of the shaved portion was less than 2 mm... Within the standard (○). The size of the shaved portion was 2 mm or more...

(2) Scratch strength measuring method Surface-type measuring instrument Type-HEIDON14
(Shinto Kagaku Co., Ltd.) and the measurement conditions were as follows: the stylus tip (needle): diamond, needle diameter: 0.01 mm, load: continuous load from 0 to 300 g, scratching speed: 10 cm / 60 sec. The tip of the chip is brought into contact with the polishing layer surface of the polishing body, and a load is continuously applied from 0 to 300 g to scratch the polishing layer. The scratches on the surface of the polished body are observed with an optical microscope, and the load at the place where the scratches reach the support is defined as the scratching strength. The evaluation of the scratching strength of the polishing layer is 300 g or more. …… within standard (△) 250 g or less …… Non-standard (×)

(3) Evaluation of process appropriateness Tape damage due to heat treatment, equipment for heat treatment,
The cost required for heat treatment and the like were used as criteria for the evaluation, and the evaluation was excellent without any problem in implementation .... (○) Implementation was possible ... (△) Impossibility was impossible ... (×).

From the results in Table 1 above, it can be seen from Examples 1 to 5 of the present invention.
In the method according to No. 8, a desirable result was obtained by heat-treating the polishing body at a temperature of 50 to 100 ° C. for a processing time of 6 to 72 hours. In the eighth embodiment, the processing time is as long as 72 hours, which is slightly inferior in terms of production in terms of cost in mass production, but there is no problem with the abrasive body itself. On the other hand, in the heat treatment at a temperature of 40 ° C. or lower in Comparative Example 2 and the treatment time of 3 hours in Comparative Example 3, the polishing layer and the back layer were insufficiently cured, and the heat treatment in Comparative Example 1 was not performed. In each of the samples, film peeling occurred, and the film was weak.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a structure of a polishing body according to one embodiment of the present invention.

FIG. 2 is a mechanism diagram showing a polishing state of a crankshaft by a polishing body.

FIG. 3 is a front view showing a polished portion of a metal crankshaft.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polishing tape (polishing body) 2 Support 3 Polishing material 4 Binder 5 Polishing layer 6 Back layer 7 Inorganic powder 8 Binder

Claims (6)

[Claims] 1. A method for manufacturing a polishing body, comprising: providing a polishing layer containing abrasive particles and a binder on one surface of a support, and providing a back layer containing an inorganic powder and a binder on the opposite surface of the support. After applying the coating solution of the polishing layer and the coating solution of the back layer on a support, and drying to provide the polishing layer and the back layer,
A method for producing a polished body, comprising: subjecting the obtained polished body to a heat treatment at a temperature and a time for promoting crosslinking of the binder to cure the polishing layer and the back layer. 2. The method according to claim 1, wherein the polishing body is for polishing a metal shaft. 3. A method for producing a polishing body, comprising providing a polishing layer containing abrasive particles and a binder on one surface of a support, wherein a coating liquid for the polishing layer is applied on the support, and dried to form the polishing layer. And then subjecting the obtained polished body to a heat treatment at a temperature and for a time to promote crosslinking of the binder to cure the polished layer. 4. The method according to claim 3, wherein the polishing body is for polishing a magnetic head. 5. The method for producing a polished body according to claim 1, wherein a heating temperature in the heat treatment of the polished body is 40 to 100 ° C., and a processing time is 4 to 72 hours. 6. The method for producing a polishing body according to claim 1, wherein the polishing body is heat-treated under humidification.