JP2012223856A - Backing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a backing material of light weight, easy to handle, excellent in restoring property and free from loss of resilience even after use of a long period, taking in no air in mounting a polishing object, while excellent in adherence to the polishing object.SOLUTION: With respect to the backing material that is fixed on a surface plate while retaining an object to be polished, a resin foam body A whose stress at 50% compression is 0.02 to 0.13 MPa, has, a continuous ventilating foamed urethan sheet B stuck on one of its faces, and having minute openings of a major diameter of 7 μm or less, and fixed to the surface plate with the another face of the resin foam body A. The backing material retains the polishing object with one face of the continuous ventilating foamed urethan sheet B.

Description

  In the present invention, when polishing the surface of a hard disk substrate, a semiconductor substrate or a semiconductor wafer, various substrates such as a glass substrate for a liquid crystal display, an LCD, etc. The present invention relates to a backing material that holds an object.

  When manufacturing an object to be polished such as a hard disk substrate used as a storage means of a computer, a silicon wafer cut out from a silicone rod, or a glass substrate for a liquid crystal display, flatness with high accuracy is required. For this reason, the surface of these substrates is polished using abrasive particles. Usually, a single-side polishing machine is used for polishing these objects to be polished. Therefore, in this polishing process, it is necessary to hold the object to be polished. However, if the object to be polished and the surface plate are brought into direct contact, the object to be polished is damaged. In order to avoid the occurrence of such scratches, a backing material made of a porous polyurethane foam suitable for holding an object to be polished has been widely used (see, for example, Patent Documents 1 and 2).

The polyurethane foam preferably has a foam surface layer (skin layer) that is dense on the surface to be polished and has a higher density than the inside. Therefore, the polyurethane foam is a water-miscible organic layer. A resin solution dissolved in a solvent is applied to a sheet-like film formation substrate, and then coagulated and regenerated in a water-based coagulation liquid.
reference).

  On the other hand, when the polyurethane foam raw material containing polyester polyols, polyisocyanates, foaming agent, catalyst and water repellency imparting agent is reacted, foamed and cured, by setting the temperature during foaming low, A backing material for forming the skin layer having a high density has been proposed (for example, see Patent Document 2).

  Furthermore, while preventing the biting of air between the adherend and the backing material, an elastic body is laminated on the base material as a holding pad where water and abrasive particle slurry do not enter the backing, The surface of this elastic body is smoothed by polishing, and an adhesive resin is coated on the smoothed surface, and a film having unevenness is pressure-bonded before the resin is completely cured, and the film is cured after the resin is cured. The backing material manufactured by peeling is proposed (for example, refer patent document 3).

JP2006-062059 JP 2006-334745 A JP 2002-355755 A

  However, since the conventional wet film forming method (for example, as described in Patent Document 1) is wet, only the foam layer has a high density, and the thickness accuracy is poor, so that polishing is necessary. It was. Furthermore, because the applied resin was manufactured by an in-situ foaming method with a 30% liquid of a water-miscible organic solvent, the recovery recovery is poor when compressed, so-called “sagging” occurs, and as a result, it cannot be used for a long time. There was an inconvenience. In addition, there is a problem that productivity is low and cost is high. In addition to these problems, the wet film forming method uses a large amount of a solvent such as N, N-dimethylformamide at the time of production. Further, when urethane produced by a wet film forming method is made into a highly foamed foam, it is difficult to freely change the foam hardness and thickness.

Further, in the conventional skin formation technique at a low temperature (for example, as described in Patent Document 2), the surface film becomes porous, so that the abrasive grains enter the pores of the film. For this reason, in order to increase the density of the film, the pad body is manufactured with a composition that does not use a foam stabilizer. However, the density of the urethane foam as an elastic body is 600 to 800 kg / m ³ and the product is extremely high. As a result, there is a problem that the weight is high and the raw material cost is high.

  Further, in the conventional backing material (for example, as described in Patent Document 3) which prevents air from being caught between the adherend and the backing material, a flat backing surface is obtained. The air entrained between the object to be polished (the object to be polished) and the holding pad is dispersed to some extent due to the uneven shape on the surface of the conductive resin. However, since the polished surface of the elastic body is not as smooth and uniform as the skin layer, the resin coating is not smooth. Furthermore, since the uneven crimping varies depending on the location, the smoothness and uniformity of the resulting holding pad is poor. As a result, in an object to be polished having a large area, such as a glass substrate for a liquid crystal television, which is increasing in size, air storage occurs when the amount of air caught between the object to be polished and the holding pad increases. Moreover, since the amount of water between the object to be polished and the holding pad is not constant, there is a problem that a constant holding force cannot be expressed.

  As a result of earnest research, the present inventor has solved urethane problems by adhering a urethane foam skin material (continuous ventilation type foamed urethane sheet) and a foam body (resin foam) with an adhesive or the like. It can be laminated with foam bodies that are difficult to integrally mold with foamed skin materials (those with different resin polarities), and it has been found that it can meet the demands of thin films of less than 1 mm, light and easy to handle, low density, and low hardness, The present invention solves the above-mentioned problems and provides a backing material that also meets the following problems.

(1) Pad material hardness and thickness can be freely adjusted by selecting various foam materials (polyurethane, polyethylene, polypropylene, EPDM, polystyrene, etc.) and adhering to a urethane foam skin material.
(2) Abrasive and water impregnation can be prevented and easy to use repeatedly.
(3) It has a high polishing holding performance capable of supporting high pressure / high rotation polishing without interposing water between the object to be polished (polishing object) and the pad material.
(4) It can meet demands for thin films (less than 1 mm), low density, and low hardness.
(5) Even during long-term use, it can be used repeatedly, reducing “sagging”.
(6) The amount of organic solvent at the time of manufacture can be reduced in combination with foam.
(7) Recyclable foam such as thermoplastic type foam can also be selected.

  In order to solve the above problems, the backing material according to claim 1 of the present invention is a backing material that is fixed to a surface plate and holds an object to be polished, and the stress at 50% compression is 0.2 to 0.13 MPa. A continuous ventilation type urethane foam sheet B having a fine opening having a long diameter of 7 μm or less is attached to one side of the resin foam A, and is fixed to a surface plate on the other side of the resin foam A. The polishing object is held on one side of the foamed urethane sheet B.

With this configuration, the resin foam A and the continuous vent type urethane foam sheet B can be selected so as to exhibit the properties of the respective holding places, and the backing material as a whole can have high performance. For example, the resin foam A has a large thickness, a small density, a suitable compressive stress and less “sag” in long-term use, and can have a low water absorption. As the skin material that adsorbs the polishing object, the hole diameter is small, the thickness is thin, the density is high, and air does not accumulate when attaching a polishing object such as a large area glass or substrate, and adsorbs to the polishing object Therefore, it can be made excellent as a backing material.
Moreover, by sticking and forming the continuous ventilation type urethane foam sheet B on the resin foam A, flexibility, lightness, and durability can be imparted to the backing material.

The reason why the stress at the time of 50% compression of the resin foam A is set to 0.02 to 0.13 MPa is that the density of the foam is 50 to make the stress at the time of 50% compression 0.02 to 0.13 MPa. It is necessary to be in the vicinity of ˜400 kg / m ³ , and by doing so, it is possible to maintain a small amount of “sagging” in a suitable compressive stress and long-term use, and to achieve low water absorption.
When the density is significantly lower than 50 kg / m ³ , the water absorption amount of the foam body increases and the adsorptivity with the object to be polished decreases. Furthermore, the lower the density, the smaller the coating amount per unit area and the higher the expansion ratio, resulting in poor thickness accuracy. On the other hand, if the density greatly exceeds 400 kg / m ³ , the foam body becomes hard and sufficient cushioning properties cannot be obtained. As a result, an object to be polished, for example, a glass substrate may be detached due to an impact during polishing. Therefore, the density is preferably 50 to 400 kg / m ³ , desirably about 100 to 300 kg / m ³ .
In addition, the continuous-venting foamed urethane sheet B is made of a foam having fine pores having a major axis of 7 μm or less. The adjustment of the degree of opening to 7 μm or less makes it possible to adsorb the object to be polished (object to be polished). In addition, the air can be released to the outside through the continuous ventilation structure of the urethane foam sheet B when adsorbing an object to be polished to the continuous ventilation foamed urethane sheet B. Can be prevented.

Further, the backing material according to claim 2 of the present invention is characterized in that the surface of the resin foam A fixed to the surface plate is smoothed and an adhesive layer is provided on the smooth surface.
With this configuration, since the surface is relatively smooth, the surface accuracy is good, the adhesive layer with a base material can be reliably attached, and the mounting property to the surface plate is improved.

The backing material according to claim 3 of the present invention is characterized in that the resin foam A is made of a thermosetting resin or a thermoplastic resin.
With this configuration, “sagging” during long-term use can be reduced, excellent restitution can be achieved, and long-term use can be achieved, and durability against repeated desorption of a polishing object can be imparted.

Moreover, the backing material according to claim 4 of the present invention is characterized in that the continuous vent type foamed urethane sheet B has a thickness of 110 μm or less and a density of 750 to 890 kg / m ³ .

With this configuration, since the thin continuous air-permeable foamed urethane sheet B having a thickness of 110 μm or less and the resin foam A are bonded together, the abrasion resistance and the continuous air-permeable foamed urethane sheet that are difficult to develop with the resin foam A alone are formed. By adjusting the degree of opening of B to 7 μm or less, the adsorption force of the object to be polished can be controlled, and when the object to be polished is adsorbed to the continuous-venting foamed urethane sheet B, the continuous ventilation structure (density 750 to 890 kg / m ³ ) allows air to escape to the outside, and as a result, air entrainment can be prevented.

The backing material according to claim 5 of the present invention is characterized in that the continuously ventilated urethane foam sheet B is made of a thermosetting resin or a thermoplastic resin.
With this configuration, the pad body that favorably adsorbs the object to be polished can be formed with a reduced thickness.

Further, in the backing material according to claim 6 of the present invention, the continuous-venting foamed urethane sheet B applies a mixed liquid containing polyurethane resin, 2-butanone, toluene and water as essential components to the process paper, and is heated. It is characterized by being obtained by doing.
With this configuration, a polyurethane resin having a molecular weight of several tens of thousands is dispersed in a mixed solvent of 2-butanone and toluene so that a thin film can be applied to a process paper such as a smooth PET film, and a foam structure is formed using water. As a result, it is possible to control the adsorptive power to the object to be polished, and further, by forming the continuous vent type foamed urethane sheet B on the resin foam A, the backing material is flexible, lightweight and Durability can be imparted.

The backing material of the present invention has the following effects.
(1) For the backing material, the resin foam A and the continuous vent type foamed urethane sheet B can be selected from foams that can exhibit the properties of their respective holding places, and the backing material as a whole has high performance. Can be freely formed. For example, the resin foam A has a large thickness, a small density, a suitable compressive stress and less “sag” in long-term use, and can have a low water absorption. As the skin material that adsorbs the polishing object, the hole diameter is small, the thickness is thin, the density is high, and air does not accumulate when attaching a polishing object such as a large area glass or substrate, and adsorbs to the polishing object The property can be good.
(2) The adsorbing power of the polishing object can be controlled by adjusting the degree of opening of the continuously vented foamed urethane sheet B as the skin material to 7 μm or less, and the polished object is adsorbed to the continuously vented foamed urethane sheet B. When it is made, air can escape to the outside through the continuous ventilation structure (density 750 to 890 kg / m ³ ) of the foamed urethane sheet B, and as a result, the biting of air (air) can be prevented.
(3) Since the backing material is formed by adhering the continuous air-permeable foamed urethane sheet B to the resin foam A, it has flexibility, lightness and durability.
(4) The backing material is constructed by adhering the continuous vent type foamed urethane sheet B having a small aperture diameter and a small thickness and a large density and a resin foam A having a large thickness and a small density. It has a high workpiece holding force that can handle high pressure and high rotation polishing, and it has little storage of air that is chewed when a polishing object (object to be polished) such as a large area glass or substrate is mounted. However, it becomes a backing material that is difficult to store.
(5) It is easy to handle lightly and can meet demands for low hardness pads.
(6) The cost can be reduced because of excellent restoration and less “sagging” even after long-term use.
(7) Since the amount of solvent such as N, N-dimethylformamide during production can be reduced, environmental contribution can be made.
(8) Since the foam layer may be a low-density urethane foam or the like, it can be provided at a low cost.
(9) It can meet demands for thin films (less than 1 mm), low density, and low hardness.
(10) There is little “sagging” in long-term use, it is excellent in resilience and can be used for a long time, and it has good durability against repeated desorption of a polishing object.

It is sectional drawing which shows the backing material which concerns on embodiment of this invention. It is sectional explanatory drawing which shows the manufacturing process of the backing material which concerns on embodiment of this invention to process order (a) (b) (c) (d) (e). FIG. 3 is an explanatory cross-sectional view showing an example of using the backing material obtained in the manufacturing process shown in FIG. 2.

Hereinafter, a backing material according to an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing a backing material according to an embodiment of the present invention. The backing material is provided with a continuous air-permeable foamed urethane sheet (hereinafter simply referred to as a foamed urethane sheet) 2 on a base material 1, and a resin foam 4 is adhered to the foamed urethane sheet 2 with an adhesive layer 3. The adhesive layer 6 with a base material is formed on the resin foam 4 with the adhesive 5 interposed therebetween. As the adhesive layer 6 with a substrate, an adhesive tape is usually used, and the adhesive 5 is protected with a release paper 1a.

  The base material 1 is a base material on which a polyurethane resin solution as a main component is applied and heated and foamed to form the foamed urethane sheet 2. Since the base material 1 is peeled off from the foamed urethane sheet 2 when used for polishing, The thing which can peel is preferable. Examples of the substrate 1 include a polyethylene terephthalate (hereinafter referred to as PET) film, or a composite film obtained by laminating a polypropylene film on paper.

The foamed urethane sheet 2 has a small hole diameter as a skin material for adsorbing an object to be polished, a small thickness and a high density, and air does not accumulate when an object to be polished such as a large area glass or substrate is mounted. Those having good adsorptivity with the object to be polished are preferred. Accordingly, the foamed urethane sheet 2 has a continuous ventilation structure having fine openings with a major axis of 7 μm or less and a thickness of 110 μm or less. Fine openings having a major axis of 7 μm or less can be formed by setting the density to 750 to 890 kg / m ³ . By making fine holes with a long diameter of 7 μm or less, the adsorptivity of the object to be polished becomes good, and when the object to be polished is adsorbed to the foamed urethane sheet 2, a continuous ventilation structure (density 750 to 890 kg / m ³ ) The air can escape to the outside through the air, and the biting of the air can be prevented. As the foamed urethane sheet 2, a thermoplastic polyurethane resin or a thermosetting polyurethane resin can be used. For example, it can be obtained by applying a liquid mixture containing polyurethane resin, 2-butanone, toluene and water as essential components to the substrate (process paper) 1 and heating.

The resin foam 4 has a large thickness, a small density, a suitable compressive stress, and less “sag” in long-term use, and a resin foam having low water absorption is preferable. Accordingly, the resin foam 4 has a 50% compression stress of 0.02 to 0.13 MPa. In order to set the 50% compressive stress to 0.02 to 0.13 MPa, the density of the foam needs to be in the vicinity of 50 to 400 kg / m ³ . A small amount of “sagging” can be maintained, and low water absorption can be achieved.
When the density is significantly lower than 50 kg / m ³ , the water absorption amount of the foam body increases and the adsorptivity with the object to be polished decreases. Furthermore, the lower the density, the smaller the coating amount per unit area and the higher the expansion ratio, resulting in poor thickness accuracy. On the other hand, if the density greatly exceeds 400 kg / m ³ , the foam body becomes hard and sufficient cushioning properties cannot be obtained. As a result, an object to be polished, for example, a glass substrate may be detached due to an impact during polishing. Accordingly, the density is preferably 50 to 400 kg / m ³ , desirably about 150 to 300 kg / m ³ .
As the resin foam 4, a thermosetting resin or a thermoplastic resin can be used. For example, thermosetting polyurethane foam, EPDM rubber foam, polyethylene foam, polypropylene foam and polystyrene foam can be exemplified.

Next, the manufacturing process of the backing material according to the embodiment of the present invention will be described. FIG. 2 is a cross-sectional view showing the manufacturing process of the backing material according to the embodiment of the present invention in the order of steps (a) (b) (c) (d) (e).
First, as shown in FIG. 2A as step 1, a mixed solution containing polyurethane resin, 2-butanone, toluene, and water as essential components is applied on a PET film 1 as a substrate and heated. Thus, the urethane foam sheet 2 is obtained.
Next, as shown in FIG. 2B as step 2, the following foaming method may be used as a method for producing a foam. In the case of a thermosetting polyurethane foam, a resin foam mixture is applied on the PET film 1 as a substrate and heated (heated) to obtain the resin foam 4. In the case of foams of thermoplastic resins such as EPDM (ethylene / propylene / non-conjugated diene copolymer rubber), EVA (ethylene vinyl acetate copolymer resin), polystyrene-based thermoplastic elastomer, etc. After kneading at a temperature of 1 mm, a 1 mm thick sheet is made of the resin with a roll, and heated and released using a press at 200 ° C. for 10 minutes to obtain a foam. In the case of a foam such as polyethylene or polypropylene resin, a foam is obtained by extrusion foaming or bead foaming after kneading a foaming agent.
Next, as shown in FIG. 2 (c) as step 3, the foamed urethane sheet 2 obtained in step 1 and the resin foam 4 obtained in step 2 are bonded together with an adhesive 3.
Next, as shown in FIG. 2D as step 4, the surface of the resin foam 4 formed in step 3 (on the side fixed to the surface plate) is polished, and the thickness is adjusted and smoothed.
Finally, as step 5, as shown in FIG. An adhesive tape (adhesive layer with substrate) 6 is attached to the smooth surface of the resin foam 4 to complete.

  As shown in FIG. 3, the backing material formed in this manner peels off the release paper 1 a of the adhesive tape 6 and attaches it to the polishing table surface plate 7 with the adhesive layer 5. Then, as shown in FIG. 3, the base material 1 of the foamed urethane sheet 2 is peeled off, and an object to be polished is placed on and adsorbed on the foamed urethane sheet 2.

In addition, when the resin foam 4 is a thermosetting foam body, the foamed urethane sheet 2 obtained in the step 1 and the resin foam 4 obtained in the step 2 are not only bonded together with the adhesive layer 3, Thermal welding is also possible.
Next, examples will be described. In each example, the same reference numerals as those in the embodiment shown in FIGS. 1 to 3 denote the same components.

100 parts of polyurethane resin solution (DIC Corporation Zortex PX550) and 50 parts of diluent solvent (mixed in a weight ratio of toluene / 2-butanone = 2/1), weight ratio of blowing agent (water / 2-butanone = 9/1) 36 parts), hexamethylene diisocyanate prepolymer (Zoltex CL-15, manufactured by DIC Corporation) as a crosslinking agent, and 1.4 parts each of an organic tin compound solution (Crisbon Axel T-81E, manufactured by DIC Corporation) as a catalyst. Added and adjusted to 25 ° C. with good mixing. The prepared soot is further stirred for 5 minutes with a stirring defoaming machine (Sinky Nentaro AR-360M, rotation 600 rpm, revolution 2000 rpm), and then applied to the PET film substrate 1 using a squeegee with a gap of 200 μm, It was dried for 60 ° C. × 1.5 min and 120 ° C. × 1.5 min to obtain a foamed urethane sheet 2 having a thickness of 35 μm and a density of 755 kg / m ³ . The maximum pore diameter was 7 μm and the cell was fine.
Next, as a polyurethane raw material, dimer acid polyester polyol (molecular weight 1236, hydroxyl value 104.4, DIC Corporation UA2812) 100 parts as polyol and prepolymer (isocyanate content) of 4.4-diphenylmethane diisocyanate and PPG as polyisocyanate 13.1 wt%, Nippon Polyurethane Co., Ltd. DC6974) was mixed at an NCO / 0H ratio of 1.03 and temperature-controlled at 35 ° C. Further, 0.2 parts of 1,8-diaza-bicyclo [5,4,0] undecene-7 organic acid salt (SA102 manufactured by Sanyo Chemical Industries, Ltd.) as a catalyst and silicone (SH192, Toray Dow Corning as a surfactant) 0.4 parts, 1 part of water was added as a foaming agent, applied on the PET film substrate 1 that had been stirred and then released, and heated at 80 ° C. × 2 min, 120 ° C. × 4 min, A thermosetting polyurethane foam (resin foam) 4 having a thickness of 1 mm and a density of 196 kg / m ³ was obtained. The foam 4 and the urethane foam sheet 2 were bonded together with an acrylic pressure-sensitive adhesive 3 (467MP manufactured by Sumitomo 3M Limited). Further, the substrate 1 was removed, and the surface of the thermosetting polyurethane foam 4 was smooth polished to adjust the thickness tolerance to ± 0.01 mm, and then the substrate-attached adhesive layer 6 was attached.

The foamed urethane sheet 2 was prepared in the same manner as in Example 1 with 28 parts of a foaming agent (mixed in a weight ratio of water / 2-butanone = 9/1) and a surfactant (Surflon S420 manufactured by AGC Seimi Chemical Co., Ltd.) 1 Parts were blended to prepare a density of 864 kg / m ³ . The foam was subjected to corona discharge irradiation (10 ekV) on the surface of the ethylene / propylene copolymer foam foamed by a press foaming machine, and was bonded to the skin material with an acrylic adhesive tape.
The resin foam 4 comprises ethylene / propylene / non-conjugated diene copolymer rubber [EPT; ethylene content 68 mol%, iodine value 12, Mooney viscosity (JIS K6300) 38] 70 parts by weight, polypropylene [PP; MFR (ASTM 1238, 230 ° C., 2.16 kg load) 5.0 / 10 min] 20 superposed parts and 10 parts by weight of a polypropylene synthetic wax (melting point 1450 ° C.), 2,5-dimethyl-2,5-di (tert-dibutyl) Peroxy) hexyne-3 [peroxide] was kneaded in the presence of 0.17 part by weight to obtain an olefin-based mature plastic elastomer for foaming.
Kneaded 2.3 parts by weight of a mixture of sodium hydrogen carbonate and citric acid (foaming agent) to the 100 parts of the obtained foaming olefin-based thermoplastic elastomer 100, and made a 1 mm thick sheet with a roll, The resin foam 4 was obtained by heating and opening using a press machine at 230 ° C. for 10 minutes. The resin foam 4 and the urethane foam sheet 2 were bonded in the same manner as in Example 1. Furthermore, after smooth-polishing the surface of the resin foam 4 and adjusting the thickness tolerance to ± 0.01 mm, the adhesive layer 6 with a substrate was attached.

The foamed urethane sheet 2 was blended with 30 parts of a foaming agent (mixed at a weight ratio of water / 2-butanone = 9/1) in the same manner as in Example 1 to prepare a density of 786 kg / m ³ . The foam was subjected to corona discharge irradiation (10 ekV) on the surface of the ethylene / vinyl acetate copolymer foam foamed by a press foaming machine and bonded to the skin material with an acrylic adhesive tape.
The resin foam 4 is composed of 100 parts by weight of ethylene vinyl acetate copolymer (melt index 10, vinyl acetate content 50%), azodicarponamide as a foaming agent and dicumyl peroxide as a crosslinking agent 10 parts, 2, 5 -The resin foam 4 was manufactured by mix | blending 0.5 part of dimethyl-2,5-dibutylperoxyhexane, and making it heat-foam. A sheet having a thickness of 1 mm was produced with a roll, and heated and released using a press machine at 200 ° C. for 10 minutes, to obtain a resin foam 4. The resin foam 4 and the urethane foam sheet 2 were bonded in the same manner as in Example 1. Furthermore, after smooth-polishing the surface of the resin foam 4 and adjusting the thickness tolerance to ± 0.01 mm, the adhesive layer 6 with a substrate was attached.

100 parts of polyurethane resin solution (Zoltex PX550 manufactured by DIC Corporation), 50 parts of diluent solvent (mixed in a weight ratio of toluene / 2-butanone = 2/1), 1 part of surfactant (Surflon S420 manufactured by AGC Seimi Chemical Co., Ltd.) , 28 parts of a foaming agent (mixed in a weight ratio of water / 2-butanone = 9/1), hexamethylene diisocyanate prepolymer (DIC Corporation Zoltex CL-15) as a crosslinking agent, and organotin compound solution (DIC) as a catalyst Each 1.4 parts of Chris Bon Axel T-81E) was added and adjusted to 25 ° C. with good stirring. The prepared liquid was further stirred for 5 minutes with a stirring defoaming machine (Shinky Ryotaro AR-360M, rotation 600 rpm, revolution 2000 rpm), and then applied to the PET film substrate 1 using a squeegee with a gap of 200 μm, It was dried for 60 ° C. × 1.5 min and 120 ° C. × 1.5 min to obtain a foamed urethane sheet 2 having a thickness of 35 μm and a density of 887 kg / m ³ . The pore size was a fine cell with a maximum of 4 μm.
Next, as a polyurethane raw material, dimer acid polyester polyol (molecular weight 1236, hydroxyl value 104.4, DIC Corporation UA2812) 100 parts as polyol and polyisocyanate 4,4-diphenylmethane diisocyanate and PPG prepolymer (isocyanate content) 13.1 wt%, DC6974 manufactured by Nippon Polyurethane Co., Ltd. was mixed at an NCO / OH ratio = 1.03, and the temperature was adjusted at 35 ° C. Further, 0.2 parts of 1,8-diaza-bicyclo [5,4,0] undecene 7 oxalate (SA102 manufactured by Sanyo Chemical Industries, Ltd.) as a catalyst and silicone (SH192, Toray Dow Corning as a surfactant) Co., Ltd.) 0.4 parts, 0.5 parts of water as a foaming agent was added, and the mixture was applied on the PET film substrate 1 which had been subjected to release treatment after stirring well, and heated at 80 ° C. × 2 min, 120 ° C. × 4 min. As a result, a thermosetting polyurethane foam (resin foam) 4 having a thickness of 1 mm and a density of 326 kg / m ³ was obtained. The resin foam 4 and the foamed urethane sheet 2 were bonded together with an acrylic pressure-sensitive adhesive 3 (467MP manufactured by Sumitomo 3M Limited). Furthermore, the base material 1 was removed, the surface of the thermosetting polyurethane foam (resin foam) 4 was smooth polished and adjusted to a thickness tolerance of ± 0.01 mm, and then the adhesive layer 6 with a base material was attached.

Comparative Example 1

The foamed urethane sheet 2 was blended with 30 parts of a foaming agent (mixed at a weight ratio of water / 2-butanone = 9/1) in the same manner as in Example 1 to prepare a density of 786 kg / m ³ . Next, as a polyurethane raw material, polyoxytetramethylene glycol (molecular weight 2862, hydroxyl value 39.2, PTMG 3000 manufactured by Mitsubishi Chemical Corporation) as a polyol and carbodiimide modified type of 4,4-diphenylmethane diisocyanate as a polyisocyanate (isocyanate content) 29.5 wt%, Nippon Polyurethane Co., Ltd. C · 98) was mixed at an NCO / OH ratio of 1.0, and the temperature was adjusted at 35 ° C. Furthermore, 0.1 part of 1,8-diaza-bicyclo [5,4,0] undecene-7 organic acid salt (SA102 manufactured by Sanyo Chemical Industries, Ltd.) is used as a catalyst, and silicone (SH192, Toray Dow Corning) is used as a surfactant. Co., Ltd.) 0.12 part, 0.15 part of water as a foaming agent was added, and the mixture was applied on the PET film substrate 1 that had been subjected to release treatment after stirring well, and added at 80 ° C. × 2 min, 120 ° C. × 4 min. Warming, a thermosetting polyurethane foam 4 having a thickness of 1 mm and a density of 403 kg / m ³ was obtained. The foam 4 and the foamed urethane sheet 2 were bonded together with an acrylic pressure-sensitive adhesive 3 (Sumitomo 3M Limited 467MP). Furthermore, the base material 1 was removed, the surface of the thermosetting polyurethane foam 4 was smooth polished, and after adjusting the thickness tolerance to ± 0.01 mm, the base material-attached adhesive layer 6 was attached.

Comparative Example 2

100 parts of polyurethane resin solution (DIC Corporation Zortex PX550) and 50 parts of diluent solvent (mixed in a weight ratio of toluene / 2-butanone = 2/1), weight ratio of blowing agent (water / 2-butanone = 9/1) 45 parts), 1.4 parts each of hexamethylene diisocyanate prepolymer (DIC Corp. Zoltex CL-15) as a crosslinking agent and organotin compound solution (Crisbon Axel T-81E, DIC Corporation) as a catalyst. Added and adjusted to 25 ° C. with good stirring. The prepared liquid was further stirred for 5 minutes with a stirring defoaming machine (Shinky Ryotaro AR-360M, rotation 600 rpm, revolution 2000 rpm), and then applied to the PET film substrate 1 using a squeegee with a gap of 200 μm, It was dried for 60 ° C. × 1.5 min and 120 ° C. × 1.5 min to obtain a foamed urethane sheet 2 having a thickness of 35 μm and a density of 695 kg / m ³ . It was a large cell with a maximum pore size of 10 μm.
Next, as a polyurethane raw material, dimer acid polyester polyol (molecular weight 1236, hydroxyl value 104.4, DIC Corporation UA2812) 100 parts as polyol and polyisocyanate 4,4-diphenylmethane diisocyanate and PPG prepolymer (isocyanate content) 13.1 wt%, DC6974 manufactured by Nippon Polyurethane Co., Ltd. was mixed at an NCO / OH ratio = 1.03 and temperature-controlled at 35 ° C. Further, 0.2 parts of 1,8-diaza-bicyclo [5,4,0] undecene-7 organic acid salt (SA102 manufactured by Sanyo Chemical Industries, Ltd.) as a catalyst and silicone (SH192, Toray Dow Corning as a surfactant) Co., Ltd.) 0.4 part, 0.5 part of water as a foaming agent was added, and the mixture was applied on the PET film substrate 1 that had been subjected to release treatment after stirring well and heated at 80 ° C. × 2 min, 120 ° C. × 4 min. Thus, a thermosetting polyurethane foam 4 having a thickness of 1 mm and a density of 326 kg / m ³ was obtained. The foam 4 and the urethane foam sheet 2 were bonded together with an acrylic pressure-sensitive adhesive (467MP manufactured by Sumitomo 3M Limited). Furthermore, the base material 1 was removed, the surface of the thermosetting polyurethane foam 4 was smooth polished, and after adjusting the thickness tolerance to ± 0.01 mm, the base material-attached adhesive layer 6 was attached.

  The characteristic measurement results of Examples 1 to 4 and Comparative Examples 1 and 2 were as shown in Table 1.

ＥＰＤＭ：エチレン・プロピレン・非共役ジエン共重合体ゴム
ＥＶＡ：エチレン酢酸ビニル共重合樹脂

EPDM: Ethylene / propylene / non-conjugated diene copolymer rubber EVA: Ethylene vinyl acetate copolymer resin

The characteristics of Table 1 and methods for measuring the thicknesses, pore diameters, etc. of the examples and comparative examples are as follows.
Holding power: A 50 × 50 mm square sample piece is attached to the test jig and adjusted so that a load of 8 g / cm ² is applied. 50 μL of water is dropped on the glass, and the sample piece is conditioned on it and allowed to stand. The sample piece was pulled horizontally with the glass plate, and the peak value of the tensile force when the sample piece was displaced was measured. Unit: N (Newton), tensile speed: 100 mm / mm. Test machine: UT4-5KN.
Air persistence: A 100 × 100 mm square glass plate is gently placed on a holding pad material wetted with 100 μl of mist of water from an inclined state of 5 °. After placing a 400 g weight on the glass for 1 minute, remove the weight and check for air. ○: No air remaining, ×: Air remaining.
Slurry persistence: 0.1 ml of slurry liquid for polishing is dropped on a 100 × 100 mm square glass plate, and a 50 × 50 mm square sample piece is allowed to stand on it. After repeatedly applying a load of 80 g / cm ² 10 times, the slurry is washed away with running water. The case where the slurry (abrasive grains) could not be visually confirmed on the surface of the holding pad material was evaluated as “◯”, and the case where the slurry was visually confirmed was evaluated as “x”.
Drying time: A glass plate of 50 × 50 mm square is left on a holding pad material wetted with a certain amount of mist water. The glass plate is moved up and down at a rate of 50% at 10 times / min for 1 minute, and then placed in an oven at 80 ° C. for 1 minute to check whether it is dry.
Thickness: A value obtained by measuring a non-foamed urethane sheet with ID-H manufactured by Mitutoyo Corporation.
Aperture diameter: A value obtained by magnifying the pore size 3500 times with an electron microscope and measuring the maximum pore diameter. A field emission scanning electron microscope S-4300 (manufactured by Hitachi, Ltd.) was used as the electron microscope.
Flatness of object to be polished: A glass substrate having a thickness of 0.5 mm is placed on the produced holding pad material, and 0.5 mL of a 20 wt% cerium oxide solution (CEPOL101 manufactured by Mabuchi S & T Co., Ltd.) is dropped to polish # 6000. After polishing with a film (manufactured by Nippon Micro Coating Co., Ltd.), centerline average roughness (Ra) was measured with a surface roughness meter (SURFCOM110A manufactured by Tokyo Seimitsu Co., Ltd.).
Compressive stress: In accordance with JIS K6400, a 30 mm × 30 mm sample was cut out and the stress value at 50% compression was measured. The compression speed is 1 mm / min. The unit is MPa. The tensile tester used was AUTO GRAPH AG-X manufactured by Shimadzu Corporation.

According to the result of Table 1, Examples 1-4 show 50% compressive stress 0.02-0.13 MPa, show a high holding force, and there is no residual air in terms of air persistence. In terms of performance, it is not possible to visually confirm the slurry (polishing abrasive grains), and it can be understood that the slurry is excellent as a backing material because it is sufficiently satisfactory in terms of drying time and flatness of an object to be polished.
Comparative Example 1 has a holding force of about 5 N as in the Example, and can hold the glass. However, when the foam is hard where the compression hardness is relatively large, such as the lip portion of the cell, polishing proceeds and polishing is performed. Since the hardness variation of the pad material is transferred to the object, high flatness after polishing cannot be expected.
The slurry residue of Comparative Example 2 uses the same foam A as in Example 3. However, since the density of the foamed urethane sheet B is 695 kg / m ³ , the pore diameter becomes 10 μm, and the surface of the foamed urethane sheet B is polished. Residue of the slurry is confirmed, which may cause poor polishing.

1 Base material (PET film)
1a Release paper 2 Continuous ventilation type urethane foam sheet (urethane foam sheet)
3 Adhesive layer 4 Resin foam 5 Adhesive layer 6 Adhesive layer with substrate (adhesive tape)
7 Surface plate 8 Edge waterproofing

Claims (6)

  In a backing material for holding an object to be polished, a continuously ventilated urethane foam having a fine opening having a major axis of 7 μm or less on one side of a resin foam A having a stress at compression of 50% of 0.02 to 0.13 MPa. A backing material, comprising: a sheet B attached thereto, fixed to a surface plate on the other surface of the resin foam A, and an object to be polished held on one surface of the continuous vent type urethane foam sheet B.   The backing material according to claim 1, wherein a surface of the resin foam A fixed to the surface plate is smoothed, and an adhesive layer is provided on the smooth surface.   The backing material according to claim 1 or 2, wherein the resin foam A is made of a thermosetting resin or a thermoplastic resin. The backing material according to any one of claims 1 to ³ , wherein the continuously ventilated urethane foam sheet B has a thickness of 110 µm or less and a density of 750 to 890 kg / m ³ .   The backing material according to any one of claims 1 to 4, wherein the continuously ventilated urethane foam sheet B is made of a thermosetting urethane resin or a thermoplastic urethane resin.   The said continuous ventilation type foaming urethane sheet B is obtained by apply | coating the liquid mixture which has a polyurethane resin, 2-butanone, toluene, and water as an essential component to process paper, and heating it. The backing material according to any one of 5.

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