JPH05293766A - Polishing body - Google Patents

Abstract

PURPOSE:To provide a polishing tape which has excellent polishing resistance even in preservation or use at a high temperature and in high humidity. CONSTITUTION:In a polishing body wherein a polishing layer, consisting mainly of abrasive particles and a binder, is formed on a support, the polishing body is formed such that the binder consists of an organic binder and an inorganic binder. The inorganic binder is in a wt.% range from 1 to 30, based on the abrasive particles. It is preferable that the polishing body prevents the drop of the abrasive particles and has excellent durability even when the thickness of the polishing layer is in a range from 1 to 10mum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing body used for polishing the surface of a magnetic head, a magnetic disk or the like.

[0002]

2. Description of the Related Art For magnetic heads or magnetic disks for video and high-quality audio, a polishing layer is formed by applying a polishing coating liquid containing an abrasive, a binder, an additive, etc. on a flexible support and drying it. It is manufactured by polishing with a polishing body. Such polishing bodies include tape-shaped or disk-shaped ones. In the case of tape-shaped ones, generally, a polishing tape is run between two reels holding a magnetic head and brought into contact with the surface to be polished for polishing. The method is taken. Also, in the case of a disc-shaped one, a method of rotating the disc to polish it is adopted.

Since such a polishing tape has a flexible support, it is more suitable for polishing a curved surface of a magnetic head or the like than a polishing grindstone, and the surface to be polished is less scratched and can be precisely polished. Since it is possible to further carry out a desired polishing process, it is indispensable for finish polishing. By the way, with the spread of VTR in recent years, the polishing tape is used and stored under a wide range of environmental conditions.

On the other hand, in addition to the binder resin, for example, a fatty acid, a fatty acid ester, a silicone oil, and a surfactant are added to the binder material of the polishing body to improve the running property of the polishing tape. Has been. In addition, a method of using an additive capable of achieving improvement in running stability, antistatic property, and dispersibility of an abrasive is also used.

By the way, most of the above organic binders have poor heat resistance and water resistance, and such a method is carried out by a method such as mixing with one or more kinds of resins or copolymerization. However, for example, many of them generally have a heat resistance of 100 ° C. or lower, and the drying temperature during the polishing tape manufacturing process is 70
It is necessary to set the temperature to -80 ° C. and to dry for a long time, resulting in a decrease in manufacturing efficiency.

Further, if the drying is not sufficient, foreign matter may be deposited on the polishing layer during use or storage, and the foreign matter may adhere to the magnetic head to cause a reduction in output or a defect on the magnetic disk or magnetic tape. I have something to do. This phenomenon is
In particular, it becomes remarkable when used and stored under high humidity, which is a serious problem in practical use. This foreign matter is contained in the polishing layer according to the so-called chromatographic principle when the organic solvent used as a solvent of the organic binder remains in the polishing layer and the residual solvent escapes from the polishing layer during storage. It is considered that a certain easy-to-precipitate component is dissolved and transferred to the surface of the polishing layer, and the soluble component is precipitated on the surface.

In a high-temperature and high-humidity environment, for example, a reaction may occur due to the mixing of a small amount of water, which may cause the peeling of the polishing layer, the attachment of polishing powder to the object to be polished, or the removal of the polishing agent. There is a problem of durability such as a cause of poor polishing. Further, it is desirable that the polishing layer be made as thin as possible, the stiffness (rigidity) be reduced to improve the polishing efficiency, and that the polishing agent can be used effectively, but an effective means for preventing the polishing agent particles from falling off cannot be found. Realization is difficult.

Conventionally, inventions have been proposed which improve the thermal and mechanical properties of the polishing layer mainly in terms of the composition of the polishing layer.
Japanese Patent Application Laid-Open No. 2-292179 discloses an example in which a polyamide film is used as a support for a polishing layer in order to improve damage due to frictional heat during polishing. Further, JP-A-3-19775 discloses an example in which a vinyl chloride / vinyl acetate copolymer / polyurethane having a glass transition temperature (Tg) of 0 to 30 ° C. is used as a binder to improve heat resistance.
JP-A-237617 discloses an example in which the dispersion stability of abrasive particles (alumina) is increased and the long-term storage stability is improved by adding an organic phosphoric acid compound. Furthermore,
EP 398580 describes that by using a specific binder resin such as polyacetylene, it is possible to suppress the generation of static electricity, prevent particles from adhering, and prevent the lifetime from decreasing even if the cutting speed is increased. There is EP-
Japanese Patent No. 438671 discloses a polishing layer containing a water-soluble polymer as a binder.

However, when the polishing tape with a thin polishing layer is used and stored under high temperature and high humidity, the above-mentioned generation of foreign matter,
No effective means has yet been proposed for the problem of peeling of the polishing layer and powder drop.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and provides a polishing tape having excellent polishing durability even in storage and use under high temperature and high humidity. The purpose is to

[0011]

DISCLOSURE OF THE INVENTION The present inventors have found that when an abrasive tape is used and stored, the abrasive layer is often peeled off from the abrasive layer, the abrasive powder adheres to the object to be abraded. As a result of earnest research on prevention of adhesion of foreign matter, the present invention has been accomplished. That is, the object of the present invention is a polishing body having a polishing layer mainly comprising abrasive particles and a binder on a support, the binder comprises an organic binder and an inorganic binder, the inorganic binder is It is achieved by an abrasive body characterized by being 1 to 30% by weight with respect to the abrasive particles.

According to the present invention, the inorganic binder is used in a specific amount with respect to the abrasive particles, and by using it together with the organic binder, the polishing layer is peeled off even during polishing work under high temperature and high humidity or during storage of the polishing body. The object of the present invention is to provide a polishing body which does not cause polishing defects such as adhesion of polishing powder. The inorganic binder used in the present invention has an affinity with the abrasive,
Because it has the property of easily interacting with the abrasive or covalently bonding to the surface of the abrasive particles, and tends to exist on the surface of the abrasive particles, and is bound to each other through an inorganic binder to form a certain aggregate structure. It is considered that in the organic binder, the structure is firmly fixed in the polishing layer organic binder as compared with the conventional structure.

Therefore, according to the present invention, even if the polishing layer is thinned, the abrasive particles can be sufficiently retained without causing powder drop or the like. In the present invention, the polishing layer has a thickness of 1 to 10 μm, preferably 3
It can be provided in the range of 6 μm. As another function of the inorganic binder, an inorganic binder having a function of hardening the surface of the abrasive particles to enhance water resistance may be included, and may have the above-mentioned functions and the like. Further, in the present invention,
The function of the inorganic binder is not limited to the above-mentioned function, and its material is not particularly limited as long as it basically functions as an inorganic material in the polishing layer. However, the organic component may be included as a side chain or the like.

Therefore, in order to further enhance the effect of the present invention, an inorganic binder having a curing function is added to the inorganic binder for forming the structure to further improve the water resistance. Multiple types can be used. As an inorganic binder, it has strong activity and enhances water resistance, but since it gels at the same time as it is mixed with an abrasive, the activity is weak on the contrary,
Even when mixed with an abrasive, some inorganic binders do not react at room temperature but react by heating.
It is determined according to the polishing body manufacturing conditions, prescription, polishing characteristics, and the like.

The conditions for the inorganic binder used in the abrasive body of the present invention preferably satisfy the following requirements. (1) The drying condition for producing the abrasive body is about 100 ° C. (2) Good affinity with water and organic binder. (3) Even if mixed or dispersed in the polishing layer, the film physical properties of the polishing layer are not deteriorated.

Specific examples of preferred inorganic binders used in the present invention include the following. Examples of the inorganic binder having a function of forming a structure mainly with an abrasive include compounds 1 to 3. (Compound 1) Water-soluble inorganic polymer Alkali metal silicate, aqueous solution of metal phosphate, silicate obtained by substituting part of alkali metal with Group II to IV metal oxide (Compound 2) Colloidal oxide (silica sol system) Aqueous Dispersion of Colloidal Particles of Silicic Acid and Rehmite (Compound 3) Silicic Acid Ester Ethyl Silicate Also, the following are mainly mentioned as the inorganic binder having a curing function of the abrasive. (Compound 4) Metal oxide / hydroxide system ZnO, MgO, SiO ₂ , Al (OH) ₃ etc. (Compound 5) Silica fluoride Na ₂ SiF ₆ (Compound 6) Phosphate 2ZnO · P ₂ O ₅ etc. in compound 7) boric acid and its salts _{H 3 BO 3, Na 2 B} 4 O 7 , etc. the present invention, amount of the inorganic binder, 1 to 30% by weight relative to abrasive particles, preferably, 5 to 25 %, More preferably 5 to 15% by weight.

If the blending amount is less than 1%, the above-mentioned function cannot be exhibited, so that the object of the present invention cannot be achieved. If the blending amount is more than 30% by weight, the flexibility of the entire polishing layer is lowered and the magnetic properties are reduced. The amount of polishing tends to vary due to non-uniform contact with the head, and the surface of the magnetic head is unevenly worn or scratched, which is not preferable.

In the present invention, the compounding ratio of the inorganic binder and the organic binder is 12 per 100 parts by weight of the organic binder.
It is in the range of 0 to 630 parts by weight, preferably 125 to 400 parts by weight. In the present invention, the method of dispersion and mixing in the preparation of the polishing layer-forming coating material comprising the above-mentioned inorganic binder, abrasive particles, organic binder resin, organic solvent, additive, etc. is arbitrary, and conventionally known methods can be applied. However, the following method is preferable.

First, the abrasive particles and the inorganic binder are mixed,
Abrasive particles and inorganic binder are mixed and dispersed with a solvent or dispersion medium of an inorganic binder to prepare an abrasive particle-inorganic binder dispersion liquid, and an organic binder, an organic solvent, and other additives are added and mixed. , The method of dispersion. Here, the dispersion medium of the abrasive particle-inorganic binder dispersion liquid is 1 to 4% by weight. Further, the dispersion liquid may be dispersed in the organic binder after removing the dispersion medium.

For example, the case where ethyl silicate is used as the inorganic binder will be described below. First, ethyl silicate is mixed into the polishing agent, and after stirring and dispersing, isopropyl alcohol, which is a solvent of the inorganic binder, is added and sufficiently stirred. The inorganic binder solvent added in a small amount is volatilized by stirring, and at the same time, the series of reactions shown in Chemical formula 1 are performed. That is, by the hydrolysis and condensation reaction, -OH and -OC are attached to the side chain of the siloxane bond.
An organosilica sol containing ₂ H ₅ is formed and interacts with the surface of the abrasive particles (it is considered that covalent bonds are also included).
Then, the abrasive particles are bound to each other through the inorganic binder particles to form an aggregate structure. The abrasive particles are then
Dispersed in an organic binder and an organic solvent, a polishing layer coating solution is prepared and coated on a support to produce a polishing body. The aggregate structure is retained even in the polishing layer. The concept of the state of the aggregate structure in the organic binder is shown schematically in FIG.

The aggregate structure 11 comprises abrasive particles 12 and inorganic binder particles 13 composed of a large number of ethyl silicate polymers bonded so as to cover the surface thereof, and the abrasive particles are inorganic binder particles. It is connected through 13.

[0022]

[Chemical 1]

The polishing agent dispersed in the polishing layer of the polishing body of the present invention is a commonly used material having a polishing action or a polishing action, such as α-alumina, γ-alumina, fused alumina, silicon carbide and chromium oxide. , Cerium oxide, corundum, artificial diamond, α iron oxide, garnet, emery (main components: corundum and magnetite), garnet, silica, silicon nitride, boron nitride, molybdenum carbide, boron carbide, molybdenum carbide, boron carbide, carbonized There are tungsten, titanium carbide, quartz, tripoli, diatomaceous earth, dolomite, etc., and materials having a Mohs hardness of 6 or more, more preferably 8 or more, are preferably used in combination of 1 to 4 kinds. The desirable average particle size of these abrasives varies depending on the purpose of polishing, and for example, about 16 to 1 μm for rough polishing and 1 to 1 for finish polishing.
About 0.1 μm is desirable.

As the binder resin used in the present invention, various resins known in the art can be used. These resins can be used alone or in combination of two or more, and examples thereof include thermoplastic resins, thermosetting resins, and reactive resins. As a thermoplastic resin, the softening temperature is 150 ° C
Hereinafter, those having an average molecular weight of 10,000 to 300,000 and a degree of polymerization of about 50 to 2,000, for example, (meth) acrylic acid ester, styrene, (meth) acrylonitrile, butadiene, vinyl ester, (meth) acrylamide, vinyl chloride, Polymers or copolymers of polymers such as vinylidene chloride or their derivatives, and copolymers with monomers copolymerizable therewith, such as vinyl chloride vinyl acetate copolymer, vinyl chloride copolymer, vinyl chloride Vinylidene chloride copolymer, vinyl acrylonitrile copolymer, acrylic acid ester acrylonitrile copolymer, acrylic acid ester vinylidene chloride copolymer, acrylic acid ester styrene copolymer, methacrylic acid ester acrylonitrile copolymer, methacrylic acid ester chloride Vinylidene Coalescence, methacrylic acid styrene copolymer, urethane elastomer, nylon-silicone resin, nitrocellulose-polyamide resin, polyfucca vinyl, vinylidene acrylonitrile copolymer, butadiene acrylonitrile copolymer, polyamide resin, polyvinyl butyral, cellulose derivative (Cellulose acetate butyrate, cellulose diacetate, cellulose triacetate, cellulose propionate, nitrocellulose, ethyl cellulose, methyl cellulose, propyl cellulose, methyl ethyl cellulose, carboxymethyl cellulose, acetyl cellulose, etc.), styrene butadiene copolymer, polyester resin, chlorovinyl ether Acrylic ester copolymer, amino resin, various synthetic rubber type Sex resins and mixtures thereof and the like can be used.

The thermosetting resin or the reactive resin has a molecular weight of 200,000 or less in the state of a coating solution.
By heating after drying, the molecular weight becomes infinite due to reactions such as condensation and addition. Among these resins, those that do not soften or melt before the resin thermally decomposes are preferable. Specifically, for example, phenol resin, phenoxy resin, epoxy resin, polyurethane curable resin, urea resin, melamine resin, alkyd resin, silicone resin, acrylic reaction resin, epoxy-polyamide resin, nitrocellulose melamine resin, high molecular weight polyester resin. And isocyanate prepolymer mixture, methacrylate copolymer and diisocyanate prepolymer mixture, polyester polyol and polyisocyanate mixture, urea formaldehyde resin, low molecular weight glycol / high molecular weight diol / triphenylmethane triisocyanate mixture, polyamine Resins, polyimine resins and mixtures thereof.

These thermoplastic resins, thermosetting resins, and reactive resins have the following carboxylic acid groups in addition to the main functional groups.
Acid groups such as sulfinic acid group, sulfenic acid group, sulfonic acid group, phosphoric acid group, sulfuric acid group, phosphon group, phosphine group, boric acid group, sulfuric acid ester group, phosphoric acid ester group, and alkyl ester groups thereof (these acidic groups May be in the form of Na salt, etc.); Amino acid group; Aminosulfonic acid group, Sulfuric acid or phosphoric acid ester group of amino alcohol; Amphoteric group such as alkyl betaine type; Amino group, imino group, imide Group, basic group such as amide group; epoxy group, hydroxyl group, alkoxyl group, which produces a hydroxyl group by reaction
Usually contains 1 to 6 types of thiol groups, halogen groups, silyl groups, siloxane groups, etc., and 1 × 1 per 1 g of resin
It is preferable to contain 0 ⁻⁶ to 1 × 10 ⁻² equivalent / g.

In the present invention, as the polar group-containing resin,
Vinyl chloride resin and polyurethane resin are preferred. In particular,
The polar group is preferably an epoxy group or a —SO ₃ M group. As the vinyl chloride resin, preferably, an epoxy group-containing vinyl chloride copolymer is used, and a vinyl chloride repeating unit, an epoxy group-containing repeating unit, and -SO ₃
And a vinyl chloride-based copolymer containing a repeating unit having M (M is synonymous with the above and is particularly preferably Na).

The polar group content of the polar group-containing resin is 1 × 1.
The range of 0 ^-6 to 1 × 10 ^-2 equivalent / g is preferable. More preferably, it is 1 × 10 ⁻⁶ to 1 × 10 ⁻² equivalent / g. The molecular weight is preferably 10,000 to 200,000. The polar group-containing polyurethane resin is specifically a polyol such as a polyether diol, a polyester diol, a polycarbonate diol, a polycaprolactone diol, and a diisocyanate, and if necessary, a polyhydric alcohol, an aliphatic polyamine, an alicyclic polyamine, It can be prepared with a chain extender such as an aromatic polyamine, and the polar group can be introduced using various means.

For example, it can be obtained by introducing a polar group into a polyester polyol using a polybasic acid or a polyol having a polar group, and reacting the polyester polyol with a polyisocyanate compound.
The polyisocyanate compound can be used as a constituent of the polyurethane resin and also as a curing agent described below for forming a three-dimensional network structure of the resin. Further, in the present invention, any curing agent can be used.

Examples of the polyisocyanate compound include di, tri and tetraisocyanates selected from aliphatic, aromatic and alicyclic compounds having two or more -N = C = O groups in the molecule. Specifically, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, naphthylene-1,5-diisocyanate, o-toluidine diisocyanate, isophorone diisocyanate, triphenylmethane triisocyanate, isophorone diisocyanate, etc. The above-mentioned isocyanates, products of the isocyanates with polyalcohols, polyisocyanates produced by condensation of isocyanates, and the like can be used. Commercially available trade names of these polyisocyanates are Coronate L, Coronate HL, Coronate 2030, Coronate 2031, Millionate MR, Millionate MTL.
(Nippon Polyurethane Co., Ltd.), Takenate D-10
2, Takenate D-110N, Takenate D-200,
Takenate D-202 (manufactured by Takeda Pharmaceutical Co., Ltd.), death module L, death module IL, death module N, death module HL (manufactured by Sumitomo Bayer Co., Ltd.), etc. are available alone or by utilizing the difference in curing reactivity. Can be used in combination of two or more. For the purpose of accelerating the curing reaction, hydroxyl groups (butanediol, hexanediol, molecular weight of 1000-100
No. 00 polyurethane, water, etc.), a compound having an amino group (monomethylamine, dimethylamine, trimethylamine, etc.), or a metal oxide catalyst can be used in combination. It is desirable that these compounds having a hydroxyl group or an amino group are polyfunctional. These polyisocyanate compounds are preferably used in an amount of 45 to 65% by weight based on the total amount of binder resin.

The organic solvent used in the present invention for dispersing, kneading and coating the abrasive particles, resin and the like can be mixed and used in any ratio. Specific examples are shown below. Acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and other ketones; methanol,
Ethanol, propanol, butanol and other alcohols; methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, glycol acetate monoethyl ether and other ester bases; ether, glycol dimethyl ether, glycol monoethyl ether, dioxane and other glycol ethers; benzene , Toluene, xylene, cresol, chlorobenzene, styrene and other tar-based (aromatic hydrocarbons); methylene chloride, ethylene chloride, carbon tetrachloride, chloroform, ethylene chlorohydrin, dichlorobenzene and other chlorinated hydrocarbons, N , N-dimethylformaldehyde, hexane and the like can be used.

The polishing layer of the present invention may contain a lubricant, a dispersant, an antistatic agent, an antifungal agent, etc. as additives in addition to the above-mentioned abrasive particles. The amount of each of these additives used is 3% by weight, preferably 2% by weight or less, based on the polishing layer.
In the present invention, various kneaders are used for kneading and dispersing in the preparation of the polishing layer-forming coating material comprising the above-mentioned inorganic binder, abrasive particles, organic binder resin, organic solvent, additives and the like. For example, two roll mill, three roll mill,
Ball mill, pebble mill, tron mill, sand grinder, segvari, attritor,
A high speed impeller disperser, a high speed stone mill, a high speed impact mill, a disper, a kneader, a high speed mixer, a homogenizer, an ultrasonic disperser and the like can be used.

As a method for forming the polishing layer on the support, a conventionally known method can be used, and details thereof are described in books such as "Coating Engineering" (Asakura Shoten 1969). The method can be done. As a coating method of the coating material prepared as described above, any coating device, for example, an air doctor coat, a blade coat,
Examples thereof include a method using air knife coat, squeeze coat, impregnation coat, reverse roll coat, transfer roll coat, gravure coat, kiss coat, cast coat, spray coat, bar coat, spin coat and the like.

Techniques relating to kneading dispersion and coating are described in T.W. C.
It is also possible to provide two or more polishing layers of different compositions at the same time by a multi-layer simultaneous coating method as described in "Paint Flow and Pigment Dispersion" (1975) by Patton (T.C. Patton). The dry thickness is determined by the use, shape, standard, etc. of the polishing tape. By such a method, the polishing layer applied on the support is optionally impregnated with a desired additive, dried, and surface-treated such as calendering.

Further, as the curing treatment, a heat treatment, an irradiation treatment with an electron beam or the like can be carried out if necessary. After that, the abrasive body of the present invention is manufactured by cutting it into a desired shape. The support used in the present invention is not particularly limited, and a commonly used support can be used. Examples of the material forming the support include polyethylene terephthalate, polyethylene, polypropylene, polycarbonate, polyethylene naphthalate, polyamide, polyamideimide, polyimide, polysulfone, films of various synthetic resins such as polyethersulfone, and aluminum foil, stainless steel. Mention may be made of metal foils such as foils. The support is generally 5 to 300 μm, preferably 10
-50 μm thick tapes, sheets,
Used in the shape of disks.

Next, the polishing body of the present invention will be described with reference to the drawings. FIG. 3 is a schematic view of a polishing apparatus using the polishing tape of the present invention. The polishing tape 1 is delivered from the tape delivery reel 6 in the direction of the arrow in the figure when the tape take-up reel 7 rotates in the direction of arrow A. The polishing tape 1 is brought into contact with a magnetic head 5 which is an object to be polished at a predetermined wrap angle by a pass roll 8 on its running path, and the tape sliding surface of the magnetic head 5 is polished.
As shown in FIG. 4, the polishing tape 1 has a polishing layer 3 coated on a flexible and non-magnetic support 2 made of polyethylene terephthalate (PET), polyethylene-2,6-naphthalate or the like. The polishing layer 3 is brought into sliding contact with the magnetic head 5 to perform polishing.
That is, as shown in FIG. 4, the tape sliding surface of the magnetic head 5 is polished smoothly by the hard polishing agent 4 protruding from the polishing layer 3.

The preferred thicknesses of the polishing layer 3 and the support 2 differ depending on the polishing shape of the magnetic head, but when the polishing tape is for finishing polishing of the above-mentioned S-VHS type magnetic head. When the thickness of the non-magnetic support is 30 μm as an example, the thickness of the polishing layer is 5 μm, and when the thickness of the support is 23 μm as an example, the thickness of the polishing layer is preferably about 10 μm. .. If the thickness of the polishing layer is too large, the contact between the magnetic head and the polishing tape will deteriorate, so the thickness of the polishing layer is preferably always 50 μm or less.

The polishing body of the present invention is particularly suitable for polishing a high performance magnetic head as described above.
When polishing the hard disk 9 as shown in FIG. 6 and FIG. 6, the hard disk is sandwiched by two rubber rollers 10, and the polishing layers of the two polishing tapes 1 are pressed by the rubber rollers 10 on both sides of the disk. By rotating 9 in the direction of arrow B, both sides of the disk can be polished simultaneously.

Further, the polishing body in the present invention is not limited to the above-mentioned tape, but also includes a disk-shaped one having a polishing layer formed on a thin circular support.

[0040]

EXAMPLES The novel effects of the polishing tape of the present invention will be described more concretely by the following examples. In the following, "part"
And “all” represent “parts by weight”. Example 1 Polishing coating liquid composition α-Fe ₂ O ₃ ...... 225 parts (granular, average particle size 0.11 μm, Mohs hardness 5.0) Cr ₂ O ₃ …… 75 parts (granular, average particle size 0.30 μm , Mohs' hardness 8.5) 5% by weight of compound 2 (colloidal silica) was added to the abrasives α-Fe ₂ O ₃ and 300 parts of Cr ₂ O _{3 in the} abrasive, and the mixture was stirred and isopropyl alcohol was used as a solvent. 20% by weight with respect to the compound 2 and sufficiently stirred
After dispersion, the following organic binder, solvent and the like were added, and the whole was sufficiently stirred and dispersed to prepare a polishing coating solution.

Vinyl chloride resin: 8.3 parts (87% by weight of vinyl chloride (average molecular weight 2.6 × 10 ⁴ ) based on the total weight of the resin, 3.5% by weight of an epoxy group, and 0. Sulfonic acid-containing polyurethane resin: 4.8 parts (molecular weight: 25,000, molecular weight per SO ₃ H: 25,000) Polyisocyanate: 9.6 parts (3 moles of 2,4-tolylene diisocyanate compound) 75 wt% ethyl acetate solution of the reaction product of 1 mol of trimethylolpropane) Methyl ethyl ketone ...... 100 parts Cyclohexanone ...... 100 parts Then, polishing coating prepared with the above composition on a polyethylene terephthalate (PET) support having a thickness of 23 μm. After applying the solution to a dry thickness of 5 μm and drying,
The polishing tape of Example 1-1 was prepared by slitting into a 1/2 inch width.

Examples 1-2 to 1-4 In Example 1-1, the addition amount of the compound 2 was 10, 15
Or, each polishing coating solution was prepared into a polishing tape in the same manner as in Example 1-1, except that the content was changed to 20% by weight. Example 2 A polishing coating solution was prepared in the same manner as in Example 1-1, except that Compound 3 (ethyl silicate) was used in place of Compound 2 in Example 1-1, and then the polishing tape of Example 2-1 was prepared. did.

Examples 2-2 to 2-4 In Example 2-1, the addition amount of the compound 3 was 10, 15
Alternatively, except for changing the content to 20% by weight, each polishing coating solution was used to prepare a polishing tape in the same manner as in Example 2-1. Comparative Example A polishing tape was prepared under the same conditions as in Examples 1 and 2 except that the compound 2 or 3 was not contained in the polishing coating liquid in Example 1 or 2.

With respect to each of the samples of Examples 1 and 2 and the comparative example prepared as described above, peeling of the polishing layer and adhesion of foreign matter to the object to be polished were evaluated by the following methods. Comparative Test 1 The magnetic head was evaluated for polishing in a high temperature and high humidity test tank.
First, each sample sample was set as shown in FIG. 2 and left in the high temperature and high humidity tank for a while.

Test tank conditions: 60 ° C., 70% Polishing conditions: Polishing tape feed rate; 18 mm / sec Head protrusion amount; 150 μm Tape back tension; 60 to 70 g Cylinder rotation speed; 1800 rpm Polishing time; 10 sec (forward / reverse) As a result of the test, when the polishing tape and the sliding surface of the magnetic head were observed with an optical microscope at a magnification of 100, in Examples 1 and 2, no polishing powder was dropped and no film was peeled off, and foreign matter was attached to the magnetic head. Was not observed. On the other hand, in the comparative example, the polishing powder was removed, and the adhesion of foreign matter to the magnetic head was recognized.

Comparative Test 2 The film strength of each polishing tape was evaluated by the scratching strength of the polishing layer. Test condition: Each sample is stuck and fixed on a glass plate without slack, and φ0.4 μm on the polishing tape.
A weight of 50 to 300 g was sequentially applied by the diamond needle of No. 1 until the time when scratches were generated on the polishing layer of the polishing tape. The results of plotting the scratching strength against the amount of the inorganic binder with respect to the polishing agent are shown in FIG. 1 (comparative example,
Although there is no inorganic binder, the scratch strength is shown by a dotted line for comparison. ).

As is apparent from FIG. 1, the abrasive body of the present invention can realize the film strength higher than that of the comparative example.

[0048]

As described above, according to the polishing tape of the present invention, by including a specific amount of a specific inorganic binder in the polishing agent, the polishing layer can be peeled off even when used under high temperature and high humidity. It is possible to suppress the generation of polishing powder, the adhesion of foreign matter to the object to be polished, and the like.

[Brief description of drawings]

FIG. 1 is a graph in which scratch strength is plotted against the amount of an inorganic binder with respect to an abrasive in Examples and Comparative Examples.

FIG. 2 is a diagram schematically showing a bonded state composed of abrasive particles and inorganic binder particles in the polishing layer of the abrasive of the present invention.

FIG. 3 is a schematic view of a polishing apparatus using the polishing tape of the present invention.

FIG. 4 is an enlarged view of the polishing tape and the magnetic head.

FIG. 5 is a schematic perspective view of another polishing apparatus.

6 is a cross-sectional view of FIG.

[Explanation of symbols]

 1 Abrasive Tape 2 Support 3 Abrasive Layer 4 Abrasive 5 Magnetic Head 6 Sending Roll 7 Take-up Reel 8 Pass Roll 9 Hard Disk 10 Rubber Roller 11 Aggregate Structure 12 Abrasive Particle 13 Inorganic Binder Particle

Claims (2)

[Claims] 1. A polishing body having a polishing layer mainly comprising abrasive particles and a binder on a support, wherein the binder comprises an organic binder and an inorganic binder, and the inorganic binder is abrasive particles. The abrasive body is characterized by being 1 to 30% by weight. 2. The polishing body according to claim 1, wherein the polishing layer has a thickness of 1 to 10 μm.