JP2017064820A - Polishing pad - Google Patents

Abstract

SOLUTION: In a polishing pad 4 which polishes a polishing object 1 having a curved part 1b and which is composed of a laminate with a polishing layer 11, an intermediate layer 13 and a cushion layer 12, the Shore A hardness of the polishing layer 11 is 20-80, the Shore A hardness of the cushion layer 12 is 10-20, and the product of a bending elastic modulus and a thickness in the intermediate layer 13 is in the range of 250-1,500 MPa.EFFECT: The peeling of a polishing layer and a cushion layer is prevented to the utmost and superior polishing results can be achieved.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a polishing pad, and more particularly to a polishing pad suitable for polishing an object having a curved surface.

Conventionally, a polishing pad has been used to precisely polish the surface of a plate-like workpiece made of glass, metal, plastic, ceramic, etc., and a polishing layer for polishing the workpiece as such a polishing pad, What has the cushion layer which supports an abrasive | polishing layer is known.
Among these, in order to polish the curved portion formed on the object to be polished, the polishing object is pressed against the polishing layer, and the polishing layer and the cushion layer are deformed along the curved portion. A pad is known (Patent Document 1).

JP 2014-138974 A

However, in the polishing pad of Patent Document 1, since the polishing layer and the cushion layer are directly bonded to each other with an adhesive, if stress is repeatedly applied to the bonding portion between the polishing layer and the cushion layer in accordance with the curved surface portion, As a result, there is a problem that a crack occurs in the bonded portion, and peeling occurs from the bonded portion, resulting in poor polishing.
In view of such a problem, the present invention provides a polishing pad that prevents the polishing layer and the cushion layer from peeling as much as possible and obtains a good polishing result.

That is, the polishing pad according to the invention of claim 1 is a polishing pad for polishing an object to be polished having a curved surface portion.
The polishing pad has a configuration in which a polishing layer, an intermediate layer, and a cushion layer are laminated, and the Shore A hardness of the polishing layer is 20 to 80, the Shore A hardness of the cushion layer is 10 to 20, and the intermediate layer The product of the bending elastic modulus and the thickness in is in the range of 250 to 1500 MPa · mm.

According to the above invention, the intermediate layer is provided between the polishing layer and the cushion layer, so that the polishing layer and the cushion layer are separated even when stress is repeatedly applied to the polishing layer along the curved surface portion of the object to be polished. Can be prevented as much as possible.
In addition, since the intermediate layer has a property that the product of the bending elastic modulus and the thickness is 250 to 1500 MPa · mm, the polishing layer follows the curved surface portion well, so that a favorable processing result can be obtained.

Side view of the polishing apparatus according to this example Enlarged sectional view of polishing pad and workpiece

FIG. 1 shows a schematic view of a polishing apparatus 2 for polishing an object 1 to be polished. The polishing apparatus 2 is located above and holds a holding surface plate 3 for holding the object 1 to be polished. A polishing surface plate 5 that is positioned below and holds the polishing pad 4 and slurry supply means (not shown) that supplies slurry between the holding surface plate 3 and the polishing surface plate 5 are provided.
The object to be polished 1 has a substantially rectangular plate shape, and a flat surface portion 1a and a curved surface portion 1b surrounding the outer peripheral edge of the flat surface portion 1a are provided on the polishing surface facing the polishing surface plate 5. And are formed.
The curved surface portion 1b is processed in advance in a chamfering device (not shown), and the polishing device 2 of this embodiment uses the polishing pad 4 provided on the upper surface of the polishing surface plate 5 to connect the flat surface portion 1a and the curved surface portion 1b. In addition, polishing is performed to a required surface roughness.
In addition, as said to-be-polished object 1, glass, a metal, a plastics, and a ceramic may be sufficient, and it may be comprised only by the curved surface part 1b, without the plane part 1a.

The holding surface plate 3 and the polishing surface plate 5 each have a substantially disk shape, and are rotated in opposite directions by driving means (not shown). The holding surface plate 3 can be moved up and down. Is provided.
The workpiece 1 is bonded and fixed to the lower surface of the holding plate 3 with a wax via a holding plate 6, and the holding plate 6 has a frame material 7 so as to surround the outside of the workpiece 1. Is provided.
When performing the polishing process, the holding surface plate 3 rotates relatively while pressing the object to be polished 1 against the polishing pad 4 on the upper surface of the polishing surface plate 5, and will be polished as described later. The flat portion 1a and the curved portion 1b are polished while the polishing pad 4 is deformed by the object 1.
The slurry supply means (not shown) supplies the slurry between the holding surface plate 3 and the polishing surface plate 5, and a conventionally known material is used as the slurry depending on the object to be polished 1 and the required processing accuracy. can do.

As shown in FIG. 2, the polishing pad 4 is fixed to the upper surface of the polishing surface plate 5 by a double-sided tape, and a polishing layer 11 having a polishing surface for polishing the workpiece 1 on the upper surface, and a polishing layer 11. And a cushion layer 12 fixed to the polishing surface plate 5, and an intermediate layer 13 provided between the polishing layer 11 and the cushion layer 12, the polishing layer 11 and the intermediate layer 13, and The intermediate layer 13 and the cushion layer 12 are bonded by an adhesive B.
As the polishing layer 11, a foamed polyurethane sheet formed by a wet film formation method can be used as a raw material, and the manufacturing method thereof includes a step of adjusting a resin solution containing a polyurethane resin and a solvent (resin solution adjustment) Step), a step of applying the resin solution to the surface of the substrate for film formation (application step), a step of coagulating and regenerating the resin in the resin solution to form a precursor sheet (coagulation regenerating step), and the above precursor sheet Each step of removing the solvent from the substrate to obtain a resin sheet (solvent removing step), and grinding the surface of the resin sheet and / or the surface opposite to the polishing surface by buffing or slicing (grinding step) It can be manufactured by passing.
The polishing layer 11 manufactured by the above manufacturing method can be set to a thickness of 0.5 to 2 mm, an A hardness of 20 to 80, and a compression rate of 3 to 20%.
Moreover, about the said cushion layer 12, a polyethylene foam and a polyurethane foam can be used as a raw material, Thickness 3-10mm, Shore A hardness is set to 10-20, Each compression rate shall be set to 25-40%. Can do.
The intermediate layer 13 may be made of polyethylene terephthalate (hereinafter may be referred to as “PET”), polyvinyl chloride (hereinafter sometimes referred to as “PVC”), or the like as a material. The product of the rate and the thickness is set to 250 to 1500 MPa · mm, and the thickness is preferably set to a range of 0.1 to 0.5 mm.
As the adhesive B that bonds the intermediate layer 13 to the polishing layer 11 and the cushion layer 12, a polyester-based adhesive can be used, and the thickness of the adhesive B can be 1 to 50 μm.

According to the polishing apparatus 2 having the above configuration, when the polishing pad 4 is mounted on the polishing surface plate 5 and the object 1 is fixed to the holding surface plate 3, the object 1 to be polished is held together with the holding surface plate 3. Lower and press against the polishing pad 4.
Then, as shown in FIG. 2, the polishing layer 11 of the polishing pad 4 is deformed along the curved surface portion 1b of the workpiece 1, and the intermediate layer 13 and the cushion layer 12 are deformed following this.
When the holding surface plate 3 and the polishing surface plate 5 are relatively rotated, the slurry supplying means supplies the slurry between the object to be polished 1 and the polishing pad 4, and the polishing pad 4 is attached to the object to be polished 1. The flat portion 1a and the curved portion 1b of the workpiece 1 are polished while being deformed according to the shape.

In the polishing apparatus 2 having the above-described configuration, the holding surface plate 3 and the polishing surface plate 5 are relatively rotated so that the polishing layer 11, the intermediate layer 13, and the cushion layer 12 of the polishing pad 4 are the same as the object to be polished 1. The deformation is repeated according to the shape.
In particular, when the polishing pad 4 is deformed along the shape of the curved surface portion 1b of the workpiece 1 and the polishing layer 11, the intermediate layer 13, and the cushion layer 12 are restored from the compressed state to the original shape, Since a force for separating them acts between them, a tensile force acts on the adhesive B. Then, as a result of the above deformation being repeated, peeling occurs from the adhesive B.
However, according to the polishing pad 4 provided with the intermediate layer 13 in the present embodiment, as is clear from the following examination results, the polishing layer 11 and the intermediate layer 13 and the intermediate layer 13 and the cushion layer 12 are also caused by the repeated stress. Peeling of the adhesive B between the two can be prevented as much as possible.
On the other hand, in the polishing pad in which the polishing layer and the cushion layer as described in Patent Document 1 are bonded with an adhesive, the adhesive between the polishing layer and the cushion layer is peeled off by repeated deformation, and polishing is performed. Defects occur.
This is presumably because openings due to bubbles were formed on the surface of a material such as polyethylene foam constituting the polishing layer and the cushion layer, so that a sufficient adhesion area by the adhesive could not be secured.
In addition, as described below, the adhesive B between the polishing layer 11 and the cushion layer 12 is thickened, or the adhesive surface of the polishing layer 11 and the cushion layer 12 is preliminarily treated to improve adhesion. However, sufficient performance cannot be obtained.

Further, according to the polishing pad 4 of the present embodiment, the hardness A of the polishing layer 11 is 20 to 80, the Shore A hardness of the cushion layer 12 is 10 to 20, and the bending elastic modulus and thickness of the intermediate layer 13 are By setting the product in the range of 250 to 1500 MPa · mm, it is possible to obtain good polishing performance while preventing the adhesive B from being peeled off as much as possible.
If the numerical value of the product of the hardness A of the polishing layer 11, the Shore A hardness of the cushion layer 12, and the flexural modulus and thickness of the intermediate layer 13 is in the above range, the polishing pad 4 is appropriately deformed on the polishing surface. This is because the intermediate layer 13 does not bend extremely although it follows the workpiece 1, and local stress (strain) is unlikely to occur between the interface between the intermediate layer 13 and the cushion layer 12.
On the other hand, when the product of the flexural modulus and the thickness is less than 250 MPa · mm, the intermediate layer 13 is well deformed according to the deformation of the polishing layer 11 when the polishing pad 4 is repeatedly deformed. A local stress (strain) is generated between the interface of the intermediate layer 13 and the cushion layer 12, and peeling is likely to occur from the site.
On the other hand, if the product of the flexural modulus and the thickness exceeds 1500 MPa · mm, the intermediate layer 13 will allow this even if the polishing pad 4 is deformed along the curved surface portion 1 b of the workpiece 1. However, as a result, the followability to the curved surface portion 1b of the polishing layer 11 is deteriorated, so that an unpolished portion is generated in the curved surface portion 1b of the object 1 to be polished.

Table 1 shown below shows the results of studies conducted on the inventive products 1 to 3 corresponding to the polishing pad 4 according to the present invention and the comparative products 1 to 4 used for comparison.
In this examination, the polishing layer 11 constituting the polishing pad 4 of the invention product 1 has a thickness of 0.5 mm, a Shore A hardness of 40, and a compression rate of 5.0%, and the other invention products 2-3. The polishing layer 11 constituting the polishing pad 4 according to the comparative products 1 to 4 has a thickness of 0.55 mm, a Shore A hardness of 50, and a compressibility of 4.0%.
The polishing layer 11 was manufactured by the resin solution adjustment process, the application process, the coagulation regeneration process, the solvent removal process, and the grinding process.
Further, the cushion layer 12 that supports the polishing layer 11 is made of Softlon SX2005 (thickness 5.0 mm, Shore A hardness 15.0, compression rate 30.0%, manufactured by Sekisui Chemical Co., Ltd.), which is a commercial product in Invention Product 1. The other invention products 2-3 and comparative products 1-3 used Softlon SX1505 (thickness 5.0 mm, A hardness 20.0, compression rate 25.0%, manufactured by Sekisui Chemical Co., Ltd.).
In addition, in the above invention products 1 to 3 and comparative products 1 to 4, a polyester-based adhesive (Esdyne 580T, manufactured by Sekisui Chemical Co., Ltd.) is used as the adhesive B. Is 20 ± 10 μm on both sides of the intermediate layer 13.

The Shore A hardness, compression rate, and flexural modulus described above are those measured by the following methods.
(Shore A hardness)
For the Shore A hardness measurement, a sample piece (10 cm × 10 cm) is prepared, a plurality of test pieces are stacked so that the thickness is 4.5 mm or more, and the A type hardness tester (Japanese Industrial Standard, JIS K 7311) is used. Measured. For example, when the thickness of one sample piece is 0.5 mm, the measurement was performed with 9 sheets stacked.
(Compression rate)
The compression rate was measured using a shopper type thickness measuring instrument (pressurized surface: circular shape with a diameter of 1 cm) in accordance with Japanese Industrial Standard (JIS L 1021). Specifically, it is as follows. The thickness t0 after applying the initial load for 30 seconds from the unloaded state was measured, and then the thickness t1 after applying the final load for 5 minutes from the state of the thickness t0 was measured. The compression rate was calculated by the equation: compression rate (%) = 100 × (t0−t1) / t0. At this time, the initial load was 100 g / cm 2 and the final pressure was 1120 g / cm 2.
(Flexural modulus)
The flexural modulus was measured using a tensile tester (Orientec, Tensilon RTA-100) according to Japanese Industrial Standard (JIS K 7171). Specifically, each sample size was 40 mm in length and 10 mm in width, and the distance between fulcrums was 22 mm. The sample used was a 1 mm thick sample made of the same material as the intermediate layer 13 used. Other conditions conformed to JIS K7171.

As shown in Table 1, the intermediate layer 13 according to Invention 1 is made of PVC, has a flexural modulus of 2900 MPa and a thickness of 0.1 mm, and the product of the flexural modulus and thickness is 290 MPa · mm. It has become.
The intermediate layer 13 according to Invention 2 is made of PET, has a flexural modulus of 2400 MPa, a thickness of 0.188 mm, and a product of the flexural modulus and thickness of 451.2 MPa · mm.
The intermediate layer 13 according to the invention 3 is made of PET, has a flexural modulus of 2400 MPa, a thickness of 0.5 mm, and a product of the flexural modulus and thickness of 1200 MPa · mm.

On the other hand, the polishing pad 4 of the comparative product 1 does not have the intermediate layer 13, and the layer of the adhesive B that bonds the polishing layer 11 and the cushion layer 12 is 40 ± 10 μm thick compared to the other polishing pads 4. It is said.
Further, the polishing pad 4 of the comparative product 2 does not have the intermediate layer 13, and the primer layer is preliminarily applied to the facing surfaces of the polishing layer 11 and the cushion layer 12, and then these are bonded by the adhesive B.
The polishing pad 4 of the comparative product 3 includes an intermediate layer 13 made of PET. The intermediate layer 13 has a bending elastic modulus of 2400 MPa and a thickness of 0.075 mm. The product is 180 MPa · mm.
Further, the polishing pad 4 of the comparative product 4 includes an intermediate layer 13 made of PET. The intermediate layer 13 has a bending elastic modulus of 2400 MPa and a thickness of 0.6 mm. The product is 1440 MPa · mm. However, the polishing pad 4 has a very high bending elasticity, and there is a problem in the followability to the object 1 to be polished.

And the polishing pad 4 concerning the said invention products 1-3 and the comparative products 1-3 was each mounted | worn to the polishing apparatus 2 which has the said structure, the polishing test was done, and peeling of the said adhesive agent B was confirmed after that. The polishing conditions at this time are as follows.
(Polishing conditions)
・ Use polishing machine: Speed Fam Co., Ltd., "Model number: DSM9B-5P-IV"
・ Surface plate speed: 40rpm
・ Processing stress: 500 g / cm2
-Abrasive: Silica slurry 20% aqueous solution-Object to be polished: Glass substrate (65 mm x 65 mm x 10 mm curved end processed) x 10 sheets / batch-Polishing time: 120 minutes / batch For the products 1 to 3, even when 250 objects to be polished 1 are polished, the adhesive B between the polishing layer 11 and the intermediate layer 13 and between the intermediate layer 13 and the cushion layer 12 is peeled off. I was not able to admit.
On the other hand, in Comparative products 1 and 2 that do not have the intermediate layer 13, 250 adhesives 1 were polished, and as a result, the adhesive between the polishing layer 11 and the cushion layer 12 was peeled off.
Moreover, about the comparative product 3 provided with the intermediate | middle layer 13 whose product of the bending elastic modulus and thickness was smaller than invention products 1-3, the adhesive agent B between the intermediate | middle layer 13 and the cushion layer 12 peeled.
As is apparent from the polishing test results, according to the inventive products 1 to 3 according to the present invention, even when the polishing pad 4 repeatedly applies stress along the curved surface portion 1b of the object 1 to be polished, the intermediate layer 13 is formed. By providing, the polishing layer 11 and the cushion layer 12 are not peeled off by the adhesive, and good polishing performance can be maintained.

DESCRIPTION OF SYMBOLS 1 To-be-polished object 1b Curved surface part 2 Polishing apparatus 4 Polishing pad 11 Polishing layer 12 Cushion layer 13 Intermediate layer B Adhesive

Claims (3)

In a polishing pad for polishing an object to be polished having a curved surface part,
The polishing pad has a configuration in which a polishing layer, an intermediate layer, and a cushion layer are laminated, and the Shore A hardness of the polishing layer is 20 to 80, and the Shore A hardness of the cushion layer is 10 to 20, A polishing pad, wherein a product of a flexural modulus and a thickness is in a range of 250 to 1500 MPa.   The polishing pad according to claim 1, wherein the thickness of the intermediate layer is set to 0.1 to 0.5 mm.   The polishing pad according to claim 1, wherein the intermediate layer is made of a material of either polyvinyl chloride or polyethylene terephthalate.

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