JP2012011516A - Polishing/holding pad - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the production cost, and at low density, the slurry containing abrasive particles does not penetrate into the pores and is excellent in restoration property, so that it can be used for a long period of time, and air is stored between the objects to be polished. Thus, a polishing holding pad is obtained which can improve environmental pollution with less solvent usage.
SOLUTION: A thermosetting urethane foam is formed on one side of an open-cell foamed urethane sheet having a fine opening having a long diameter of 10 μm or less, and the heat is applied to a surface plate for holding an object to be polished. In the polishing holding pad in which the other surface side of the curable urethane foam is fixed and the other surface side of the open-cell foamed urethane sheet comes into contact with the object to be polished, the open-cell foamed urethane sheet has a thickness of 110 μm or less. The density is 990 kg / m ³ or less, and the thermosetting urethane foam has a compression set of 10 or less.
[Selection] Figure 2

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 or the like, the polishing table is interposed between a polishing table and an object to be polished. The present invention relates to a polishing holding pad for holding 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 polishing table are brought into direct contact, the object to be polished is damaged. In order to avoid the occurrence of such scratches, polishing holding pads made of a porous polyurethane foam suitable for holding an object to be polished have 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 polishing holding pad for forming the skin layer having a high density has been proposed (see, for example, 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. A polishing holding pad produced by peeling is proposed (see, for example, 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, in the conventional skin formation technique at a low temperature (for example, as described in Patent Document 2), since the surface film becomes porous due to open cells, the abrasive grains enter the pores of the film. End up. 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 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 is stored when the amount of air caught between the polishing object 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.

  The present invention has been made in view of the above-described problems, and its purpose is to reduce production costs, and the slurry containing abrasive grains does not penetrate into the pores while being low in density, so that it can be restored. An object of the present invention is to provide a polishing holding pad that can be used for a long time because it is excellent and that there is no storage of air between the object to be polished and the amount of solvent used can be reduced, so that environmental pollution can be improved.

In order to achieve the object, the polishing holding pad according to claim 1 of the present invention has a thermosetting urethane foam formed on one side of an open-cell foamed urethane sheet having fine pores having a major axis of 10 μm or less. The other surface side of the thermosetting urethane foam is fixed to a surface plate for holding the object to be polished, and the other surface side of the open-cell foamed urethane sheet is in contact with the object to be polished. The open-cell foamed urethane sheet has a thickness of 110 μm or less, a density of 990 kg / m ³ or less, and the thermosetting urethane foam has a compression set of 10 or less. To do.

According to the polishing holding pad having this configuration, since the thin open-cell foamed urethane sheet (A) having a thickness of 110 μm or less and the thermosetting urethane foam (B) are integrally formed, the thermosetting urethane foam (B) Abrasion resistance that is difficult to express by itself and adjusting the degree of opening of the foamed urethane sheet (A) to 10 μm or less can control the adsorption force of the object to be polished, and the object to be polished ( Air can be released to the outside through the open cell structure (density 990 kg / m ³ or less) of the urethane foam sheet (A) when sticking the object to be polished), and as a result, the air can be prevented from being caught. it can.
Further, by suppressing the permanent compression strain of the thermosetting urethane foam (B) to 10 or less, durability against repeated detachment of the object to be polished can be imparted to the polishing holding pad.

  In addition, if the thickness of the open-cell foamed urethane sheet (A) is greater than 110 μm, a large open cell is formed as compared with 10 μm having a maximum diameter of about 1 mm, and a smooth foamed urethane sheet (A) is obtained. I can't get it. Further, when the foam (B) is integrally formed on one side of the open-cell foamed urethane sheet (A) with the thermosetting urethane foam (B), the foam (B) is formed by uniting cells. The cell becomes rough and causes voids.

In the polishing holding pad according to claim 2 of the present invention, the open-cell foamed urethane sheet applies a mixed liquid containing polyurethane resin, 2-butanone, toluene and water as essential components to the process paper, It is obtained by heating.
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, the adsorptive power to the object to be polished can be controlled, and furthermore, by forming the thermosetting urethane foam (B) integrally with the urethane foam sheet (A), the polishing holding pad is flexible. Light weight and durability can be imparted.

Further, in the polishing holding pad according to claim 3 of the present invention, the surface fixed to the surface plate of the urethane foam is subjected to a thickness adjustment smoothing treatment, and an adhesive is applied to the smooth surface, or an adhesive tape. Are pasted together.
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 polishing holding pad according to the present invention has the following effects.
(1) An open-cell foamed urethane sheet having a small aperture diameter and a small thickness and a large density and a thermosetting urethane foam having a large thickness and a small density are integrally formed to constitute a polishing holding pad. Therefore, it has a high workpiece holding power that can handle polishing at higher pressures and rotations, and it has less storage of air when it is mounted on a workpiece such as a large area glass or substrate. It becomes a hard polishing holding pad.
(2) It is light and easy to handle and can meet the demand for low hardness pads.
(3) Since it has excellent recoverability and has less “hang” even during long-term use, cost can be reduced.
(4) Since the amount of solvent used such as N, N-dimethylformamide during production can be reduced, environmental contributions can be made.
(5) Since the foam layer may be a low-density urethane foam, it can be provided at a low cost.

It is sectional explanatory drawing which shows the manufacturing process of the pad for polishing holding | maintenance which concerns on this invention in process order (a) (b) (c) (d). It is sectional explanatory drawing which shows an example of a usage pattern.

Hereinafter, a polishing holding pad according to an embodiment of the present invention will be described in detail with reference to the drawings.
First, the production of an open-cell foamed urethane sheet in FIG. A base plastic 1 (such as PET-100GS manufactured by Lintec Corporation) is coated with a mature plastic polyurethane resin (Zoltex PX-550 manufactured by DLC Co., Ltd.) using a squeegee, for example, 60 ° C. × 1-5 min, and further 120 ° C. × Dry for 1 to 10 minutes to obtain a foamed urethane sheet 2 having a thickness of 110 μm or less and a density of 990 kg / m ³ or less. Or what apply | coated the thermosetting urethane foam raw material to the base material 1 is heated, a foaming reaction and crosslinking hardening are carried out, and the foaming urethane sheet 2 is obtained.
In FIG. 1, 1 can be a polyethylene terephthalate (hereinafter abbreviated as PET) film, paper + polypropylene laminate, etc., which has been subjected to a release treatment on one side, and 2 is an open-cell foamed urethane sheet (thermoplastic polyurethane). Resin or thermosetting polyurethane resin).

Next, as an integral molding step of the thermosetting urethane foam in Step 2 of FIG. 1B, a polyurethane raw material is applied to the surface of the foamed urethane sheet 2 with the base material 1, and the base material 4 is further covered and heated. (80 ° C. × 2 min, 120 ° C. × 4 min) A thermosetting polyurethane foam 3 is obtained. Or you may apply | coat a polyurethane raw material to the base material 4, and also cover the base material 1 and heat (80 degreeC * 2min, 120 degreeC * 4min), and you may make it foam.
In FIG. 1, this type of urethane foam is used in order to reduce the compression set of the thermosetting polyurethane foam 3 to 10 or less and reduce “sagging” even during long-term use. In addition, 4 is a base material which can be peeled off from the thermosetting polyurethane foam 3, and polyethylene terephthalate (PET) film is preferably used, and in addition, polyvinyl chloride (PVC), nylon film and the like can be used. Listed in the material.

In the next thermosetting urethane foam polishing step of step 3 in FIG. 1C, the substrate 4 is peeled off and the surface of the thermosetting polyurethane foam 3 is polished to a uniform thickness.
In the subsequent step 4 (FIG. 1 (d)), the adhesive layer 5 with the substrate is bonded to the polished surface of the thermoset urethane foam 3 that has been subjected to polishing. In addition, the adhesion layer with a base material is comprised by the adhesive-PET film-adhesive-separator.

Furthermore, an example of the usage pattern is shown in FIG.
The polishing holding pad created in Step 4 of FIG. 1D is cut into a predetermined shape, and the cut surface (end) is waterproofed 7. Depending on the use conditions, the waterproof treatment 7 at the end is not necessary.
When using this pad, first, the substrate 1 is peeled off, and then 5 ′ from which the separator of the adhesive layer 5 with the substrate is peeled off is attached to the surface plate 6. Then, on the open-cell foamed urethane sheet 2 from which the substrate 1 has been peeled off, for example, a glass substrate is adsorbed by the surface tension of water as an object to be polished through water and subjected to polishing.

  The open-cell foamed urethane sheet that comes into contact with the object to be polished (the object to be polished) of the polishing holding pad is made by polyaddition of diisocyanate and polyol as long as it has the characteristics of claim 1. As long as it is polyurethane, it may be either thermoplastic or thermosetting resin.

The thermosetting polyurethane foam 3 interposed between the open-cell foamed urethane sheet and the surface plate must be a thermosetting polyurethane foam having a compression set of 10 or less according to claim 1. For that purpose, the density needs to be around 200 to 400 kg / m ³ . By doing so, not only can a compressive stress suitable as a polishing holding pad and a small amount of “sagging” in long-term use be maintained, but also low water absorption can be achieved. When the density is significantly lower than 200 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, there is a concern that the glass substrate to be polished may come off due to impact during polishing. Thus, density is 200~400kg / ^{m 3,} preferably preferably 300 kg / ^{m 3} before and after.

  The thermosetting polyurethane foam 3 is selected from polyols, polyisocyanates, foaming agents, catalysts, and optionally crosslinking agents, colorants, resin modifiers, refractory agents, ultraviolet absorbers, and durability improvers. After the reaction raw material obtained by mixing and stirring a compound such as an additive is uniformly applied to the release surface of the process paper (base material) 4 subjected to the release treatment, the base material 1 is formed on the upper surface of the application raw material. It can be manufactured by covering the attached foam sheet 2 and forming an open-celled polyurethane foam.

  Examples of the polyols include polyester polyols and polyether polyols, and using a hydrophobic polyol is preferable because a polyurethane foam having a contact angle with water of 90 ° or more can be obtained. For example, polybutadiene-based polyol, dimer acid-based polyol, castor oil-based polyol, polycarbonate-based polyol, polypropylene glycol, polytetramethylene glycol and the like can be mentioned. Among these, polytetramethylene glycol is preferable because it has high strength and can withstand long-term use. In addition, dimer acid-based polyols are particularly preferred because of their high hydrophobicity.

  Moreover, as a polyfunctional isocyanate, the aromatic isocyanate which contains two or more isocyanate groups in a molecule | numerator, and fatty acid group isocyanate those modified products can be used. Specifically, toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), xylene diisocyanate (XDI), tetramethylxylylene diene Isocyanate (TMXDI) and the like, and mixtures thereof can be used, but are not limited thereto. Further, by using these as prepolymers, the elongation, strength and durability are improved, and long-term use becomes possible.

  Examples of the blowing agent include water, nitrogen gas at normal pressure, inert gas such as carbon dioxide and air, halogenated alkanes such as monofluorinated trichloromethane and chloromethane, low-boiling alkanes such as butane and pentane, and decomposed nitrogen Azobisisobutylnitrile and the like that generate gas and the like and mixtures thereof are used, but are not limited thereto.

  The thermosetting polyurethane foam 3 as an elastic body to be mounted on the fixed surface plate 6 of the polishing holding pad of the present invention is not limited to the manufacturing method shown in the above embodiment, but also includes the raw materials as described above. It may be produced by a conventionally known method such as a one-shot method or a partial prepolymer method. The polyurethane foam to be produced is molded into a sheet by molding, continuous sheet molding, mechanical floss molding, or the like. In particular, the “sheet-shaped foaming method” in which the polyurethane stock solution is sandwiched between the release paper on the upper and lower surfaces and the open-cell foamed polyurethane sheet shown in the above embodiment and foamed is the most suitable method.

Next, the present invention will be described in detail with reference to examples and comparative examples. In the following, “part” and “%” are units based on weight.
In all of the examples and comparative examples, the polyurethane resin solution (Zoltex PX550 manufactured by DIC Corporation) used for the production of the open-cell foamed urethane sheet is polyether / polyester, and the crosslinking agent (T- manufactured by DIC Corporation). 81E) uses hexamethylene diisocyanate prepolymer / hexamethylene diisocyanate, and the catalyst solution (CL-15 manufactured by DIC Corporation) uses an organotin catalyst containing less than 1% (dibutyltin dilaurate) and an ethyl acetate / 2-butanone solution. As the surfactant (Surflon S420 manufactured by AGC Seimi Chemical Co., Ltd.), a perfluoroalkylethylene oxide copolymer was used.

100 parts of a polyurethane resin solution (Zoltex PX550 manufactured by DIC Corporation) is mixed with 50 parts of a diluent solvent (mixed in a weight ratio of toluene / 2-butanone = 2/1), and a foaming agent (water / 2-butanone = 9/1). 20 parts by weight), 1.5 parts each of a crosslinking agent and a catalyst, and 1 part of a perfluoroalkylene ethylene oxide copolymer (AGC Seimi Chemical Co., Ltd. S420) as a surfactant was added with good stirring. Adjusted to 25 ° C. The prepared liquid was further stirred for 5 minutes with a stirring deaerator (Shinky Awatori Rentaro AR-360M, rotation 600 rpm, revolution 2000 rpm), and then coated on the PET film substrate 1 using a squeegee with a gap of 100 μm. And dried for 60 ° C. × 2.5 min and 120 ° C. × 5 min to obtain a foamed urethane sheet 2 having a thickness of 5 μm and a density of 867 kg / m ³ . It was a fine cell with a maximum pore size of 3 μm.
Next, as a polyurethane raw material, 100 parts of dimer acid polyester diol (molecular weight 1236, hydroxyl value 104.4, DIC Corporation UA2812) 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 / OH ratio = 1.05, and the temperature was adjusted to 35 ° C. Furthermore, 0.4 parts of 1,8-diaza-bicyclo [5,4,0] undecene-7 organic acid salt (SA102 manufactured by Sanyo Chemical Industries, Ltd.) is added as a catalyst, and 0.5 part of water is added as a blowing agent. It is applied on a PET film substrate 4 which has been well-stirred and then subjected to a release treatment, and is covered with a foamed urethane sheet 2 with a PET film substrate 1 so that the polyurethane raw material and the foamed urethane sheet are in contact with each other, 80 ° C. × 2 min, 120 ° C. × 4 min. Heating was performed to obtain a thermosetting polyurethane foam ³ having a thickness of 1 mm and a density of 300 kg / m ³ . Furthermore, the base material 4 was removed, the surface of the thermosetting polyurethane foam 3 was smooth polished, and after adjusting the thickness tolerance to ± 0.01 mm, the base material-attached adhesive layer 5 was attached.

100 parts of a polyurethane resin solution (Zoltex PX550 manufactured by DIC Corporation) is mixed with 50 parts of a diluent solvent (mixed in a weight ratio of toluene / 2-butanone = 2/1), and a foaming agent (water / 2-butanone = 9/1). 80 parts, 1.5 parts each of a crosslinking agent and a catalyst, and 1 part of a perfluoroalkylene ethylene oxide copolymer (AGC Seimi Chemical Co., Ltd. S420) as a surfactant is added with good stirring. Adjusted to 25 ° C. The prepared liquid is further stirred for 5 minutes with a stirring defoamer (Shinky Awatori Rentaro AR-360M, rotation 600 rpm, revolution 2000 rpm), and then coated on the PET film substrate 1 with a squeegee having a gap of 500 μm. And dried for 60 ° C. × 2.5 min and 120 ° C. × 5 min to obtain a foamed urethane sheet 2 having a thickness of 110 μm and a density of 538 kg / m ³ . It was a fine cell with a maximum pore size of 3 μm. Thereafter, the same operation as in Example 1 was performed to produce a composite urethane sheet with an adhesive tape.

100 parts of a polyurethane resin solution (Zoltex PX550 manufactured by DIC Corporation) is mixed with 50 parts of a diluent solvent (mixed in a weight ratio of toluene / 2-butanone = 2/1), and a foaming agent (water / 2-butanone = 9/1). 80 parts, 1.5 parts each of a crosslinking agent and a catalyst, and 1 part of a perfluoroalkylene ethylene oxide copolymer (AGC Seimi Chemical Co., Ltd. S420) as a surfactant is added with good stirring. Adjusted to 25 ° C. The prepared liquid is further stirred for 5 minutes with a stirring defoaming machine (Shinky Awatori Rentaro AR-360M, rotation 600 rpm, revolution 2000 rpm), and then coated on the PET film substrate 1 using a squeegee with a gap of 200 μm. And dried for 60 ° C. × 2.5 min and 120 ° C. × 5 min to obtain a urethane foam sheet 2 having a thickness of 48 μm and a density of 444 kg / m ³ . It was a fine cell with a maximum pore size of 6 μm.
Next, 100 parts of polyol component polytetremethylene glycol (molecular weight 2000, hydroxyl value 57, Mitsubishi Chemical Co., Ltd. PTMG2000) 5 parts trimethylolpropane trimethacrylate (Mitsui Chemicals IR94) 4,4 as polyisocyanate -A prepolymer of diphenylmethane diisocyanate and PPG (isocyanate content 13.1 wt%, DC6974 manufactured by Nippon Polyurethane Co., Ltd.) was mixed at an NCO / OH ratio = 1.05, and the temperature was controlled at 35 ° C. Furthermore, 0.4 parts of 1,8-diaza-bicyclo [5,4,0] undecene-7 organic acid salt (SA102 manufactured by Sanyo Chemical Industries, Ltd.) is added as a catalyst, and 0.5 part of water is added as a blowing agent. It is applied after stirring well, and the foamed urethane sheet 2 with PET film substrate 1 is covered so that the polyurethane raw material and the foamed urethane sheet are in contact with each other, heated at 80 ° C. × 2 min, 120 ° C. × 4 min, thickness 1 mm density; 300 kg / m ³ elastic body was obtained. Furthermore, the base material 4 was removed, the surface of the thermosetting polyurethane foam 3 was smooth polished, and after adjusting the thickness tolerance to ± 0.01 mm, the base material-attached adhesive layer 5 was attached.

100 parts of a polyurethane resin solution (Zoltex PX550 manufactured by DIC Corporation) is mixed with 50 parts of a diluent solvent (mixed in a weight ratio of toluene / 2-butanone = 2/1), and a foaming agent (water / 2-butanone = 9/1). 28 parts), 1.5 parts each of a crosslinking agent and a catalyst, and 1 part of a perfluoroalkylene ethylene oxide copolymer (AGC Seimi Chemical Co., Ltd. S420) as a surfactant are added with good stirring. Adjusted to 25 ° C. The prepared liquid is further stirred for 5 minutes with a stirring defoaming machine (Shinky Awatori Rentaro AR-360M, rotation 600 rpm, revolution 2000 rpm), and then coated on the PET film substrate 1 using a squeegee with a gap of 200 μm. And dried for 60 ° C. × 2.5 min and 120 ° C. × 5 min to obtain a foamed urethane sheet 2 having a thickness of 30 μm and a density of 987 kg / m ³ . It was a fine cell with a maximum pore size of 3 μm.
Thereafter, the same operation as in Example 1 was performed to produce a composite urethane sheet with an adhesive tape.

100 parts of a polyurethane resin solution (Zoltex PX550 manufactured by DIC Corporation) is mixed with 50 parts of a diluent solvent (mixed in a weight ratio of toluene / 2-butanone = 2/1), and a foaming agent (water / 2-butanone = 9/1). 40 parts by weight were added with good stirring and adjusted to 25 ° C. The prepared liquid is further stirred for 5 minutes with a stirring defoamer (Shinky Awatori Rentaro AR-360M, rotation 600 rpm, revolution 2000 rpm), and then coated on the PET film substrate 1 with a squeegee having a gap of 500 μm. And dried for 60 ° C. × 2.5 min and 120 ° C. × 5 min to obtain a foamed urethane sheet 2 having a thickness of 86 μm and a density of 587 kg / m ³ . It was a fine cell with a maximum pore size of 7 μm.
Next, as a polyurethane raw material, 100 parts of dimer acid polyester diol (molecular weight 1236, hydroxyl value 104.4, DIC Corporation UA2812) as polyol and prepolymer (isocyanate content) of 4,4-diphenylmethane diisocyanate and PPG as polyisocyanate 13.1 wt%, DC6974 manufactured by Nippon Polyurethane Co., Ltd. was mixed at an NCO / OH ratio = 1.05, and the temperature was controlled at 35 ° C. Furthermore, 0.4 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 0.3 parts of water as a blowing agent were added, It is applied on a PET film substrate 4 which has been well-stirred and then subjected to a release treatment, and is covered with a foamed urethane sheet 2 with a PET film substrate 1 so that the polyurethane raw material and the foamed urethane sheet are in contact with each other, 80 ° C. × 2 min, 120 ° C. × 4 min. Heating was performed to obtain a thermosetting polyurethane foam ³ having a thickness of 1 mm and a density of 443 kg / m ³ . Further, the PET film substrate 4 was removed, the surface of the thermosetting polyurethane foam 3 was smooth polished, and the thickness tolerance was adjusted to ± 0.01 mm, and then the adhesive layer 5 with a substrate was attached.

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) 40 parts) was adjusted to 25 ° C. with good stirring. The prepared liquid is further stirred for 5 minutes with a stirring defoaming machine (Shinky Awatori Rentaro AR-360M, rotation 600 rpm, revolution 2000 rpm), and then coated on the PET film substrate 1 using a squeegee with a gap of 200 μm. And dried for 60 ° C. × 2.5 min and 120 ° C. × 5 min to obtain a foamed urethane sheet 2 having a thickness of 40 μm and a density of 670 kg / m ³ . The pore size was a fine cell with a maximum of 7 μm.
Next, as a polyurethane raw material, 100 parts of dimer acid polyester diol (molecular weight 1236, hydroxyl value 104.4, DIC Corporation UA2812) as polyol and prepolymer (isocyanate content) of 4,4-diphenylmethane diisocyanate and PPG as polyisocyanate 13.1 wt%, DC6974 manufactured by Nippon Polyurethane Co., Ltd. was mixed at an NCO / OH ratio = 1.05, and the temperature was controlled at 35 ° C. Further, 0.4 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 0.8 parts of water as a blowing agent were added, It is applied on a PET film substrate 4 which has been well-stirred and then subjected to a release treatment, and is covered with a foamed urethane sheet 2 with a PET film substrate 1 so that the polyurethane raw material and the foamed urethane sheet are in contact with each other, 80 ° C. × 2 min, 120 ° C. × 4 min. Heating was performed to obtain a thermosetting polyurethane foam ³ having a thickness of 1 mm and a density of 230 kg / m ³ . Further, the PET film substrate 4 was removed, the surface of the thermosetting polyurethane foam 3 was smooth polished, and the thickness tolerance was adjusted to ± 0.01 mm, and then the adhesive layer 5 with a substrate was attached.

Comparative Example 1

100 parts of a polyurethane resin solution (Zoltex PX550 manufactured by DIC Corporation) is mixed with 50 parts of a diluent solvent (mixed in a weight ratio of toluene / 2-butanone = 2/1), and a foaming agent (water / 2-butanone = 9/1). 80 parts, 1.5 parts each of a crosslinking agent and a catalyst, and 1 part of a perfluoroalkylene ethylene oxide copolymer (AGC Seimi Chemical Co., Ltd. S420) as a surfactant is added with good stirring. Adjusted to 25 ° C. The prepared liquid was further stirred for 5 minutes with a stirring deaerator (Shinky Corporation Awatori Rentaro AR-360M, rotation 600 rpm, revolution 2000 rpm), and then coated on the PET film substrate 1 using a squeegee with a gap of 600 μm. And dried for 60 ° C. × 2.5 min and 120 ° C. × 5 min to obtain a foamed urethane sheet 2 having a density of 448 kg / m ³ . The foamed urethane sheet had a thickness of 120 μm, and as for the pore diameter, bumps of the solvent were observed on the surface, so that a coarse hole with a maximum of 120 μm was observed, and the surface on the unevenness was observed. Thereafter, the same operation as in Example 1 was performed to produce a composite urethane sheet with an adhesive tape.

Comparative Example 2

The solution was diluted with a 1: 2 organic solvent of 2-butanone: toluene so that the solid content of the thermoplastic polyurethane resin 2 (Zoltex PX-550 manufactured by DIC Corporation) was 20%, and adjusted to 25 ° C. while stirring well. The prepared liquid was further stirred for 5 minutes with a stirring defoaming machine (Shinky Awatori Rentaro AR-360M, rotation 600 rpm, revolution 2000 rpm) and then squeegee with a gap of 200 μm on PET film substrate 1 (Lintec Corporation). Was applied and dried for 60 ° C. × 2.5 min and 120 ° C. × 5 min to prepare a foamed urethane sheet 2 having a thickness of 26 μm.
Further, an elastic body was foamed thereon in the same manner as in Example 1. Furthermore, the base material 4 was removed, the surface of the thermosetting polyurethane foam 3 was smooth polished, and after adjusting the thickness tolerance to ± 0.01 mm, the base material-attached adhesive layer 5 was attached.

Comparative Example 3

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) 20 parts), 3 parts each of a crosslinking agent and a catalyst were added, and 1 part of a perfluoroalkylene ethylene oxide copolymer (A420 manufactured by AGC Seimi Chemical Co., Ltd.) as a surfactant was adjusted to 25 ° C. with good stirring. . The prepared liquid is further stirred for 5 minutes with a stirring defoaming machine (Shinky Awatori Rentaro AR-360M, rotation 600 rpm, revolution 2000 rpm), and then coated on the PET film substrate 1 using a squeegee with a gap of 200 μm. And dried for 60 ° C. × 2.5 min and 120 ° C. × 5 min to obtain a foamed urethane sheet 2 having a thickness of 44 μm and a density of 568 kg / m ³ . The pore size was a maximum of 5 μm and a fine cell.
Next, as a polyurethane raw material, 100 parts of dimer acid polyester diol (molecular weight 1236, hydroxyl value 104.4, DIC Corporation UA2812) as polyol and prepolymer (isocyanate content) of 4,4-diphenylmethane diisocyanate and PPG as polyisocyanate 13.1 wt%, DC6974 manufactured by Nippon Polyurethane Co., Ltd. was mixed at an NCO / OH ratio = 95, and the temperature was adjusted at 35 ° C. Furthermore, 0.4 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 0.5 parts of water as a blowing agent were added, It is applied on a PET film substrate 4 which has been well-stirred and then subjected to a release treatment, and is covered with a foamed urethane sheet 2 with a PET film substrate 1 so that the polyurethane raw material and the foamed urethane sheet are in contact with each other. Heating was performed to obtain a thermosetting polyurethane foam ³ having a thickness of 1 mm and a density of 288 kg / m ³ . Further, the PET film substrate 4 was removed, the surface of the thermosetting polyurethane foam 3 was smooth polished, and the thickness tolerance was adjusted to ± 0.01 mm, and then the adhesive layer 5 with a substrate was attached.
Although a holding force value of 4.1 N was relatively good, the restoring property was 12%, and settling due to repeated desorption was generated.

※開孔径値の−は、非発泡シートのためセルが無い状態を指す。

* The negative pore size value-indicates a non-foamed sheet with no cells.

The meaning of each term in Table 1 and Table 2 is shown below.
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 / min. Testing 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.

Restorability: 50% compression set promoted in a 70 ° C. oven.
Foamed urethane sheet resin: Thermoplastic means a material made using a thermoplastic polyurethane resin, and thermosetting means a sheet made using a thermosetting polyurethane resin.
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 by 3500 times with an electron microscope and measuring the maximum aperture diameter. A field emission scanning electron microscope S-4300 (manufactured by Hitachi, Ltd.) was used as the electron microscope.
Contact angle: This is a value obtained by measuring the contact angle with water using a contact angle meter after applying each polyurethane raw material onto a mirror-finished PET and drying it to form a smooth film. As a contact angle meter, Kyowa contact angle meter CA-A type (manufactured by Kyowa Science Co., Ltd.) was used.
Polyurethane foam: An ester refers to a polyurethane foam that is foamed under specified conditions using various polyester polyol raw materials. An ether is a polyurethane foam that is foamed under predetermined conditions using a polyether polyol raw material. Say.
Abrasion resistance: JIS K5600-5-9 <Coating film / mechanical properties (Section 9; Abrasion resistance (Abrasion wheel method)) compliant wear wheel; 400 samples using H-18, load 250g It is a value obtained by measuring the subsequent weight loss rate (%). A tea bar type (manufactured by Toyo Seiki) was used as an abrasion resistance tester.

  From the results shown in Table 1, in Examples 1 to 6, the thickness, open pore diameter, contact angle and density of the open-cell foamed urethane sheet that adsorbs and holds the object to be polished, and the type of polyurethane foam, that is, the ester type Or, the ether type has some variation in holding power, resilience, wear resistance, etc., but it is in a satisfactory range, and results that are sufficiently satisfactory in air persistence (air biting), slurry persistence, and drying time. Has been obtained. In addition, as is clear from the values in the column of holding power in Table 1, the holding power is larger than that of the comparative example, so that it can cope with higher pressure / high rotation polishing, and is a glass substrate for a large-screen LCD TV. This is a polishing holding pad suitable for polishing.

  On the other hand, from the results shown in Table 2, in Comparative Example 1, the thickness of the foamed urethane sheet is as thick as 120 μm, and a large hole of 120 μm at the maximum due to a bump bump trace of the solvent is observed on the surface, and the smoothness of the surface is impaired and retained. The force was lowered, and both air and slurry residues were practically rejected. Moreover, although Comparative Example 2 was a non-foamed sheet, there was no problem with the remaining amount of the slurry. However, since the surface was almost flat, the holding force was 2.8, which was smaller than that of the Example, and air retention However, the results were not satisfactory for practical use. In Comparative Example 3, a relatively good holding force value of 4.1 N was obtained, but the restorability was 12%, and sag due to repeated desorption was not preferable.

DESCRIPTION OF SYMBOLS 1 Base material 2 Open-cell foamed urethane sheet 3 Thermosetting urethane foam 3 'Polished thermosetting urethane foam 4 Base material 5 Adhesive layer with a base material (State which attached the separator)
5 'Adhesive layer with substrate (separator is peeled off)
6 Surface plate 7 Waterproof treatment of the edge

Claims (3)

A thermosetting urethane foam is formed on one side of an open-cell foamed urethane sheet having fine pores with a long diameter of 10 μm or less, and the thermosetting urethane foam is placed on a surface plate for holding an object to be polished. In the polishing holding pad in which the other surface side of the body is fixed and the other surface side of the open-cell foamed urethane sheet is in contact with the object to be polished, the open-cell foamed urethane sheet has a thickness of 110 μm or less and a density of 980 kg / m ³ or less, wherein the thermosetting urethane foam has a compression set of 10 or less.   The said open-cell type foaming urethane sheet is obtained by apply | coating to the process paper the liquid mixture which has a polyurethane resin, 2-butanone, toluene, and water as an essential component, and heating. Polishing holding pad.   The fixed surface to the surface plate of the thermosetting urethane foam is subjected to thickness adjustment smoothing treatment, and an adhesive material is applied to the smooth surface, or an adhesive tape is bonded thereto. The polishing holding pad according to 1 or 2.

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