JP2857038B2 - Polishing tape - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing tape and, more particularly, to polishing in a field requiring a high finish, particularly useful for polishing metals, magnetic layer surfaces of magnetic recording media, ceramics, wood, plastics, and the like. Polishing tape.

[0002]

2. Description of the Related Art Conventional polishing tapes are composed of fine particles of inorganic substances having high hardness such as iron oxide, alumina, silicon carbide, and chromium oxide as a polishing agent, and a thermoplastic polyester resin, a vinyl chloride copolymer, and a polyurethane resin as a binder. , A polyamide resin, an acrylic resin, and the like are dispersed and dissolved in an organic solvent, and this is applied to a plastic film, for example, a polyester film.

[0003] However, this kind of conventional polishing tape has the following improvement requests and problems. (1) If the abrasive particles protrude significantly from the surface of the polishing layer, scratches and scratches are likely to occur on the surface to be polished. (2) In response to recent demands for advanced polishing finish, conventional polishing tapes have reached the limit in terms of quality even if measures such as uniform distribution of abrasive particle size and strict control of coating are taken. ing. (3) With a conventional tape, it is difficult to adjust the pressure appropriately on the object to be polished, and a fine work is required for setting. In other words, when the pressure is low, the time required for polishing is long, while when the pressure is high, many scratches are generated on the surface to be polished, and as a result, poor finishing is likely to occur. (4) As measures against these problems, it has been proposed to make the binder of the polishing layer an elastic material, and to make the glass transition point of the polymer be lower than ordinary temperature. There is still room for improvement. In addition, this kind of binder has low heat resistance, and in an operation of increasing the pressing of the polishing tape, etc., large deformation and deterioration due to softening of the binder due to an increase in frictional heat occur, not only adverse effects on the surface to be polished, Significantly shorten the life of the tape. (5) As another measure, a buffer layer is provided between the polishing layer and the base film, for example, as disclosed in JP-A-63-10 / 1988.
3957, JP-A-1-240274, JP-A-4-3
No. 0972 and the like, and polyurethane, polyethylene, polypropylene and the like are mentioned as the material of the buffer layer. However, these have a processing problem that the adhesion strength with the polyester film, which is often used as a base film, is difficult to obtain in an extrusion coat, which is high enough to withstand use. The use of a special anchor coating agent or the adoption of a tandem extrusion coating method undesirably increases costs and complicates processing. Furthermore, there is a lack of quality stability such that there is a variation in the polishing property, particularly the scratch property, of the object to be polished by the polishing tape, and further improvement in quality is desired.

[0004]

The inventors of the present invention have made intensive studies to solve the above-mentioned problems and demands for improvement. As a result, at least one side of the polyester film contains polybutylene terephthalate or butylene terephthalate as a main repeating unit. A crystalline copolymer polyester is used as a hard segment, and a layer of an elastic polyester having a glass transition point of 10 ° C. or less and a rebound resilience at 23 ° C. of 30 to 85% is 5 μm.
It is possible to solve the above-mentioned problems by laminating with a thickness of at least m and providing a polishing layer thereon, and in particular to greatly improve the scratching property, besides having a low secondary transition point of the buffer layer. The inventors have found that it is necessary to provide a high rebound resilience, and have reached the present invention.

Accordingly, it is an object of the present invention to remedy the drawbacks of the prior art, to significantly improve the occurrence of scratches on the polished surface,
An object of the present invention is to provide a polishing tape capable of forming a high-quality finished surface.

[0006]

According to the present invention, there is provided, according to the present invention, at least one surface of a polyester film in which a hard segment comprises a crystalline polyester having butylene terephthalate as a main repeating unit, and has a glass transition temperature. 10 ° C. or less and a rebound resilience (23 ° C.) of 30
This is achieved by a polishing tape in which a layer of elastic polyester of 85% is laminated with a thickness of 5 μm or more, and a polishing layer is provided thereon.

The elastic polyester according to the present invention is characterized in that the hard segment comprises a crystalline polyester having butylene terephthalate as a main repeating unit. As the crystalline polyester, polybutylene terephthalate or a copolymerized polyester in which butylene terephthalate accounts for 70% or more of the total repeating units is preferable.

Examples of the soft segment of the elastic polyester include aliphatic polyethers such as polytetramethylene glycol and aromatic dicarboxylic acids (terephthalic acid,
A hardly crystalline or non-crystalline copolyester comprising an isophthalic acid or the like and an aliphatic dicarboxylic acid having 4 to 12 carbon atoms (for example, adipic acid or pimelic acid) and a glycol having 2 to 6 carbon atoms is preferable.

As a specific method for producing such an elastic polyester (polyester elastomer), for example, Japanese Patent Publication No. Sho 6
Although detailed descriptions are given in JP-A-35365, JP-A-58-141236, etc., the elastic polyester used in the present invention is not limited to these.

The first reason for using a crystalline polyester having butylene terephthalate as a main repeating unit (hereinafter sometimes abbreviated as a PBT-based crystalline polyester) for the hard segment of the elastic polyester in the present invention is that it has good polishing properties. 30 to 8 which is the rebound elasticity region showing
The range of 5% can be easily controlled by the ratio of the hard segment to the soft segment and the copolymer composition of the soft segment (affecting the secondary transition point). The second reason is that the polyester used as the base material of the polishing tape Lamination workability with a film, especially lamination adhesion, is much better than other elastic polymers such as polyolefins, polystyrenes, polyvinyl chlorides, polyurethanes and the like. The heat resistance (softening point) is as high as 150 to 200 ° C. Therefore, even if high frictional heat is transmitted from the polishing layer during polishing, and at the same time, even if a large pressure is applied, fluid deformation does not occur. Polyester film, maintaining high adhesion to the polishing layer, maintaining rebound resilience, maintaining other physical properties, etc. That.

A preferable hard segment of the elastic polyester is 100% of a butylene terephthalate component.
The reason for using 70% or more of the copolymer from the (homopolymer) is that if it is less than 70%, the crystallinity (crystallinity, speed, etc.) decreases, the function as a hard segment decreases, and the polishing characteristics of the present invention deteriorate. It is because they are not satisfied enough. In terms of function and cost, a hard segment composition with 100% polybutylene terephthalate is more desirable.

Further, the elastic polyester of the present invention comprises
As described above, the block copolymer of the hard segment (polybutylene terephthalate) and the soft segment is used, and the ratio is appropriately selected depending on the desired elastic modulus, heat resistance, and the like. To obtain the polishing tape of the present invention, the amount of the hard segment is suitably from 20 to 60% by weight.

In the present invention, the elastic polyester must have a glass transition point of 10 ° C. or less, preferably 5 ° C.
It is as follows. The main reason is that, when the temperature of the polishing work environment becomes lower than that in winter, its elasticity is lost, and the object of the present invention cannot be achieved. The glass transition point mainly depends on the composition (component, copolymerization ratio) of the soft segment, and the design value can be obtained by adjusting these.

In the present invention, the elastic polyester must further have a rebound resilience of 30 to 85%, preferably 40 to 70%. This characteristic is JIS K63
According to No. 01, measured at 23 ° C., if it exceeds 85%, the impact applied to the polishing layer and the absorption and relaxation of excessive pressure become insufficient, and as a result, the object of the present invention cannot be sufficiently achieved. . On the other hand, if it is less than 30%, adjustment of the pressing of the polishing tape to the surface to be polished becomes somewhat difficult.

In the present invention, the elastic polyester is laminated on the polyester film to a thickness of 5 μm or more, preferably 15 μm or more. Is unsatisfactory in terms of occurrence of The thickness of the layer is 50
It is preferably not more than μm.

Further, for example, the following method is applied as a lamination method on a polyester film.

A) melt extruding the elastic polyester into a film on an polyester film by an extruder;
The so-called extrusion coating method is economical, suitable for mass production, and is the most effective means for obtaining the polishing tape of the present invention. In this case, the polyester film side has a high level of adhesion strength (5) that can be sufficiently used as a polishing tape only by a generally performed corona discharge treatment.
It is a feature that the above-mentioned value is obtained.
For other elastic polymers such as olefins, polyvinyl chlorides, polystyrenes, etc., the adhesion strength is extremely low by corona treatment alone and cannot be used as a polishing tape. In order to obtain even higher adhesion strength,
A combination of a corona treatment and a subsequent application of an anchoring agent to be applied can be employed, but an isocyanate-based anchoring agent is suitable at this time.

B) Another method is a method in which an elastic polyester is once formed into a film by a melt extrusion method, and then laminated with a polyester film by a lamination device (generally referred to as dry lamination or hot melt lamination). However, it is particularly suitable for small-lot production when the lamination thickness is increased. Urethane-based adhesives are examples of effective adhesives, and Dick Dry LX, sold by Dainippon Ink and Chemicals, Inc.
SF and Toyo Morton's MD series correspond.

In the present invention, as the polyester film of the base film, polyethylene terephthalate, polyethylene-2,6-naphthalate, and a biaxially stretched film comprising a copolymer containing these as a main component can be preferably mentioned. .

The polishing tape of the present invention is produced by providing a polishing layer on the above-mentioned laminated elastic polyester layer by a known means. In other words, iron oxide as an abrasive, alumina, silicon carbide, fine particles such as oxidized clona,
Furthermore, saturated polyester resin, PVC
Dissolve and disperse, if necessary, lubricants, dispersants, antistatic agents, etc. in vinyl acetate copolymer resin, polyurethane resin, etc., in an organic solvent, apply on the elastic polyester coated surface, and then immediately dry Is obtained.

The polishing tape of the present invention has a rebound resilience of 30 to 85 between the base polyester film and the polishing layer.
% Of the elastic polymer layer effectively absorbs and relieves excessive pressure and local pressure applied during polishing, thereby preventing scratches and scratches on the surface to be polished, and furthermore uniformity Demonstrate the best polishing ability.
In addition, the use of a specific elastic polyester greatly contributes to high lamination strength, high heat resistance, and improvement in the durability of the tape, and can be evaluated as a polishing tape having excellent overall performance.

[0022]

The present invention will be further described below with reference to examples.

Example 1 and Comparative Example 1 Polybutylene terephthalate (hard segment 30% by weight), isophthalic acid (80% by mole), sebacic acid (20% by mole) and hexamethylene glycol (100% by mole) A chip of a block copolymer elastic polyester (glass transition point of -9 ° C, rebound resilience of 61%, melting point of 205 ° C) composed of a coalesced material (soft segment of 70% by weight) is dried at 120 ° C for 4 hours and then extruded with a 55 mmφ extruder. Polyethylene terephthalate film (S-type commercially available from Teijin, Ltd.) having a thickness of 25 μm and having been subjected to corona treatment (single side) at 225 ° C. by melt extrusion into a film shape, surface tension of 54 d of corona treated surface
yn / cm) to a thickness of 30 μm. The lamination peel strength was as high as 520 g / 15 mm width (peel strength: 300 mm / min, peel angle 180).
°).

On the other hand, as a binder for the polishing layer, a linear random copolymerized polyester resin (non-crystalline) in which the acid component is 50 mol% each of isophthalic acid and terephthalic acid and the glycol component is 50 mol% each of ethylene glycol and neopentyl glycol , Glass transition point 62 ° C)
The following polishing paint was prepared. Polyester resin: 40 parts by weight Abrasive particles: aluminum oxide (average particle size: 1.0 μm) 200 parts by weight Solvent (a mixture of methyl ethyl ketone, toluene and ethyl acetate in the same volume ratio) 200 parts by weight A 10 μm thick polishing layer was formed by coating and drying on the elastic polyester laminated surface. Thereafter, the tape was slit to a width of 1/2 inch to produce a polishing tape.

On the other hand, as Comparative Example 1, the polishing paint of Example 1 was applied directly to a corona discharge treated surface of a 38 μm-thick polyethylene terephthalate film (S-type commercially available from Teijin) to a thickness of 10 μm to form a conventional polishing tape. Was prepared.

The evaluation of the polishing property was performed by the apparatus shown in FIG.
Reference numeral 8 denotes a running polishing tape, 4 denotes a ferrite polished body (round bar having a diameter of 10 mm), 2, 3, 5, and 6 denote free rolls, 1 denotes an unwinding roll of the polishing tape 8, and 7 denotes a polishing tape. The winding roll. The round bar of the object to be polished is in contact with the polishing tape at an angle of 155 °. The polishing tape speed is 100 cm / min and the polishing time is 30
Min (abrasive tape length 30 m).

After polishing both the polishing tape of Example 1 and the conventional polishing tape of Comparative Example 1 under the above-described evaluation conditions, the surface condition of the round bar of the object to be polished was observed. as a result,
The polishing tape according to the present invention has no scratches and has a uniform polishing state (uniform gloss). On the other hand, the surface of the conventional tape has many scratch-like scratches, and the polished state is uneven, with streak-like ones conspicuous.

[0028]

The polishing tape of the present invention exhibits excellent performance in preventing scratches and scratches on the object to be polished and for achieving a smooth hardness finish, as compared with the conventional type.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus for evaluating the polishing performance of a polishing tape.

[Explanation of symbols]

 1: Unwinding roll of polishing tape 2, 3, 5, 6: Free roll 4: Ferrite round bar of the object to be polished 7: Winding roll of polishing tape 8: Polishing tape

Claims (3)

(57) [Claims] At least one side of a polyester film has a hard segment made of crystalline polyester containing butylene terephthalate as a main repeating unit, has a glass transition temperature of 10 ° C. or less, and has a rebound resilience (23 ° C.).
A polishing tape obtained by laminating an elastic polyester layer having a thickness of 30 to 85% with a thickness of 5 μm or more and providing a polishing layer thereon. 2. The polishing tape according to claim 1, wherein the crystalline polyester constituting the hard segment is polybutylene terephthalate or a copolymerized polyester in which butylene terephthalate accounts for 70% or more of all repeating units. 3. The polishing tape according to claim 1, wherein the polyester film is a polyethylene terephthalate film or a polyethylene-2,6-naphthalate film.