KR100811399B1 - Absorbing pad and manufacturing method thereof - Google Patents

Abstract

A polishing pad having even surface and strong adsorption property to adsorb an object to be polished without performing a water spray process, and a method of manufacturing the polishing pad are provided. A polishing pad having even surface and strong adsorption property includes a foamed polyurethane sheet formed on a film on one side and buffed polyurethane surface on the other side, a back-up layer(5), an adhesive layer(6) and a peel-off layer(7).

Description

Absorbing pad and manufacturing method for polishing

1 is a cross-sectional view illustrating a process of forming a polishing pad for polishing according to the present invention.

1A is a cross-sectional view of an initial state in which a foamed polyurethane sheet is formed on a film forming film, and FIG. 1B is a cross-sectional view of a surface layer of the foamed polyurethane sheet buffed and polished,

1C is a cross-sectional view of a polishing pad having a support layer, an adhesive layer, and a release agent layer sequentially formed on the buffing surface;

Figure 2 is a schematic diagram showing an apparatus and a process for producing a polishing pad for polishing according to the present invention,

3 to 5 are views illustrating a process of forming a suction pad manufactured according to each embodiment of the present invention.

6 is an apparatus for measuring the adsorption force of the adsorption pad, wherein (a) is a plan view and (b) is a sectional view.

* Explanation of symbols for main parts of the drawings

1 --- polyurethane sheet 2 --- foamed surface layer

3 --- foaming cell 4 --- micro foam layer

5 --- support layer 6 --- adhesive layer

7 --- Release layer 8 --- Suction pad

25 --- Solidification tank 29 --- Washing tank

30 --- drying tenter

B --- Polyurethane Sheet Surface Layer

B '--- buff polished face

G --- Polishing surface

P --- film formation film

The present invention relates to an abrasive pad for polishing and a method for manufacturing the same, and more particularly, a support layer, an adhesive layer, and a release paper layer are sequentially attached by buffing a surface having fine irregularities of the manufactured polyurethane sheet. And a flat surface separated from the PET film as a part having a closed type micro fine cell structure formed on the PET film used as a substrate and not directly contacting water. It relates to a polishing suction pad formed of cotton and a manufacturing method thereof.

Generally, materials such as glass for liquid crystal displays, silicon wafers, substrates for hard disks, and the like are polished using an abrasive cloth because their surfaces require high precision flatness. In general, the grinding process is a double-sided grinder for polishing both sides of the workpiece at the same time, a single-side polisher for polishing only one end surface, etc. In the single-side polisher, the upper surface of the workpiece is adsorbed on a pressure plate having a flat surface and attached to a rotating surface with a flat surface. The bottom surface of the to-be-polished material is polished, supplying a polishing liquid to one polishing cloth. At this time, the upper surface of the object to be polished is directly in contact with the metal platen, so scratches or the like occur on the object to be polished. Therefore, in order to avoid the occurrence of such scratches, a method of attaching a protective pad of the soft cross to the pressure plate may be used.

However, in the conventional method described above, the protective pad may act as a buffer between the abrasive and the pressurized plate to prevent scratches, but the abrasive may move during the grinding process because the absorption of the abrasive is insufficient. There is a problem of poor flatness.

Therefore, in order to prevent the movement of such a to-be-processed object, the processing method of inserting and polishing a to-be-processed object to a template etc. is performed.

However, the conventional improved method described above not only has to take the inconvenience of removing the polished object from the template after polishing, but recently, the polished material has been enlarged, especially in the case of a glass substrate for a liquid crystal display. The disadvantage is that it is practically impossible. Therefore, there is a demand for a large adsorption pad having a high flatness capable of adsorbing a polished object without using a template.

The adsorption pad is generally a foamed polyurethane sheet, and in detail, the foamed polyurethane sheet is coated with a resin solution obtained by dissolving a polyurethane resin in an organic solvent on a film-forming flooring material on a sheet, and then, It is manufactured by the process of solidifying and washing a polyurethane solution by substitution of an organic solvent. On the surface of the prepared polyurethane sheet, a foam surface layer having a thickness of about several μm in which dense foam is formed is formed. Since such foaming is foaming formed by the substitution of the organic solvent and water contained in the polyurethane resin solution, the surface of the skin layer has fine irregularities. However, in such a wet film formation method, since the resin solution is viscous, a thickness variation occurs during application to the film formation substrate, and a thickness variation tends to occur due to coagulation and replacement of the organic solvent and the aqueous coagulation solution at the time of washing. In the conventional adsorption pad using a foamed polyurethane sheet having a thickness variation as described above, when the abrasive is adsorbed onto the pad and polished, the pressure added to the abrasive is increased in the portion where the thickness of the adsorption pad is high. There was a disadvantage that the surface is unevenly polished to reduce the polishing efficiency.

Therefore, in order to reduce the thickness variation in the foamed polyurethane sheet as described above, a method of buffing the surface after the production of the foamed polyurethane and then using the treated surface as the adsorption surface of the adsorption pad has been proposed and used. have. Another method is to attach the polishing pad to the pressure plate of the polishing machine, and then attach the flat calibration material to the suction pad before performing the polishing process, and operate the polishing machine like the polishing process to correct the thickness deviation and flatten the surface of the absorption pad. The technique to say is proposed. In addition, the adsorption pad which has been further developed has been recently proposed and used by buffing the back surface without buffing the skin layer of the foamed polyurethane sheet.

However, in the conventional methods described above, since the skin layer of the foamed polyurethane sheet used as the adsorption surface is a surface formed by direct substitution with a coagulant solution containing water as a main component, the viscosity of the polyurethane resin originally possessed is largely lost. There is a disadvantage in that the adsorption force is insufficient to adhere the polishing object, and therefore, it is not preferable because the adsorption force has to be improved by performing a pretreatment process such as a water spray when attaching the polishing object.

When describing the technical details of the conventional adsorption pad in more detail, the conventional adsorption pad is a fine surface layer formed during solidification since the polyurethane adsorption layer formed in direct contact with the coagulation liquid in the coagulation bath is used as the adsorption surface. As the unevenness remains as it is on the adsorption surface, the polishing efficiency is not good. There was a drawback of deterioration, and it was difficult to improve the flatness of the processed surface because the thickness variation of the foamed polyurethane skin layer remained as the thickness variation of the adsorption pad as it remained when the skin layer was left. Furthermore, since the work of correcting the thickness deviation before polishing is performed, the working efficiency of the entire polishing is reduced. In order to solve this drawback, in the case of the adsorption pad that buffed the opposite side without buffing the skin layer of the foamed polyurethane sheet, the flatness was somewhat improved, but the adsorption force, which is one of the most important performances of the adsorption pad, was improved. There is still a disadvantage in that it is greatly inadequate to be subjected to a pretreatment process such as water spray on the surface of the adsorption pad or the polishing object when adsorbing the polishing object.

Therefore, the present inventors have found that the above problems can be solved by forming adsorption surfaces under specific conditions as a result of intensive studies on adsorption pads and methods for manufacturing the above problems. It was completed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a polishing adsorption pad having high adsorption force without pretreatment process such as water spray so as to reliably adsorb the to-be-polished, and to have a fine flatness of the processed surface of the to-be-polished object.

Another object of the present invention is to provide an easy manufacturing method of a polishing pad having the above characteristics.

In order to solve the above object of the present invention, it is important to reduce the thickness variation and to have a strong adsorption force while maintaining the fine flatness of the adsorption surface during the preparation of the adsorption pad.

Polishing adsorption pad of the present invention for achieving the above object;

The surface of the foamed polyurethane sheet formed on the film forming film is the adsorption surface, and the opposite surface of the foam surface layer is buff polished, and the support layer, the adhesive layer and the release agent layer are sequentially formed to constitute the pressure plate adhesion layer. .

According to another configuration of the present invention, the polyurethane sheet is characterized in that it comprises 3 parts by weight to 7 parts by weight of the cell regulator with respect to 100 parts by weight of the polyurethane resin solution.

Method for producing a polishing pad of the present invention for achieving the above another object;

1) preparing a polyurethane resin solution by dissolving the polyurethane resin in a soluble organic solvent and then mixing the additives;

2) applying the polyurethane resin solution continuously to a uniform thickness on a film of the substrate;

3) solidifying the film coated with the polyurethane resin solution in a coagulation bath, and washing with water in a water bath;

4) drying the washed coated film;

5) buffing the surface of the dried coated film; And

6) attaching a support layer to the buffing surface, and characterized in that the step of removing the base film.

According to another configuration of the present invention, the organic solvent for dissolving the polyurethane resin is characterized in that N, N-dimethylformamide (dimethylformamide; DMF).

According to another configuration of the present invention, the polyurethane resin is characterized in that 100% Modulus is selected from 20 to 40kg / ㎠ about polyester, polyether, polycarbonate resin.

According to another configuration of the present invention, the polyurethane resin is characterized in that it is dissolved to 15 to 25 parts by weight of DMF 75 to 85 parts by weight.

According to another configuration of the present invention, sodium dioctyl sulfossucinate / Isopropyl alcohol (80/20) is 3 weights as a cell regulator with respect to 100 parts by weight of the polyurethane resin solution. It is characterized by containing from 7 parts by weight to parts.

According to another configuration of the present invention, the additive is characterized in that pigments such as carbon black, hydrophilic active agents, hydrophobic active agents, fluorine-modified polyurethane resin is used.

According to another configuration of the present invention, the polyurethane resin solution is characterized by using a viscosity of 10,000 to 20,000cps by degassing under vacuum after removing impurities and the like by filtration.

According to another configuration of the present invention, the coating step, the solidification and washing step, the drying step is characterized in that it is carried out continuously.

According to another configuration of the present invention, the base film is characterized by using a P.E.T film.

The present invention constituted as described above is made by using a flat layer formed without direct contact with water of a foamed polyurethane sheet having an ultrafine foam structure of a sealed type separated from a PET film used as a film forming substrate, as the adsorption surface. Urethane maintains the inherent viscosity to the end and has a strong adsorption force. Furthermore, by buffing the surface layer of the foamed polyurethane sheet, the foam cells present therein protrude outward, thereby only eliminating the surface irregularities and overall thickness variation of the skin layer formed by contact with water in the production of the foamed polyurethane sheet. Rather, it lowers the resilience of the adsorption pad against the pressure received in the polishing process, thereby increasing the polishing efficiency and further enhancing the adsorption power of the polishing object.

In addition, in the conventional adsorption pad, as the polishing process continues, the polishing liquid penetrates into the adsorption pad, and the abrasive is continuously laminated in the adsorption pad, and thus the polishing efficiency begins to decrease. As a result, the performance of the adsorption pad is generally lost. While the life time is only 72 to 96 hr, the adsorption pad according to the present invention constituted as described above essentially blocks the inside of the pad from penetrating the polishing liquid because its surface is composed of a very fine foam layer. The degradation of polishing efficiency caused by the infiltration of the polishing liquid during long time use is eliminated and the lifespan of the adsorption pad is increased to 144 to 168hr, which is about twice the life of the conventional adsorption pad.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a cross-sectional view showing the formation process of the polishing pad according to the invention, Figure 1a is a cross-sectional view of the initial state in which the foamed polyurethane sheet is formed on the film forming film, Figure 1b is a surface layer of the foamed polyurethane sheet buffing 1C is a cross-sectional view of a polishing pad having a support layer, an adhesive layer, and a release agent layer sequentially formed on the buffing surface.

As shown in FIG. 1A, the adsorption pad 8 has a foamed polyurethane sheet 1 formed of a polyurethane resin. Polyurethane sheet 1 is composed of both sides of the polyurethane sheet surface layer B, which is the surface to be polished, the adsorption surface G and the surface B 'which is subsequently buffed, and the inside thereof is a large foam cell 3, a small foam cell 3' and a very fine foam layer 4 It consists of. The polyurethane sheet surface layer B is buff polished so that the thickness of the polyurethane sheet 1 is almost uniform. As described above, the polyurethane sheet 1 on which the polyurethane sheet surface layer B is buff polished is manufactured such that the difference between the maximum thickness and the minimum thickness is 2% or less in the thickness average, and the maximum thickness when the thickness average of the polyurethane sheet 1 is about 1 mm. The difference between and the minimum thickness is less than about 20㎛. For this reason, the polyurethane sheet 1 has a flat adsorption surface G. FIG.

On the adsorption surface G side of the polyurethane sheet 1, the hermetic ultrafine foam layer 4 supports the fine flatness of the adsorption surface G. In the lower layer of the micro-foamed layer 4, a relatively large and uniform large foamed cell 3 long oval is formed along the thickness direction of the polyurethane sheet 1, and a small foamed cell 3 ', which is crowded below and relatively small spherical, is formed. The space volume of the large foaming cell 3 is larger in size on the adsorption surface G side than on the side opposite the adsorption surface G. In the microfine foam layer 4 between the foaming cell 3 and the foaming cell 3, a very fine foaming cell is formed. As shown in Fig. 1B, the relatively large and elliptical large foamed cell 3 and the spherical small foamed cell 3 'with small space volume are blast-polished in the lower part so that the foamed cell is open to the surface on the back side all over the surface. .

Moreover, the adsorption pad 8 has the support layer 5 which supports the polyurethane sheet 1 on the opposite side to the adsorption surface G. As shown in FIG. A plastic film such as P.E.T film may be used for the support layer 5. An adhesive layer 6, such as a double-sided tape for attaching the adsorption pad 8 to the polishing machine, is attached on the support layer 5, and the release paper layer 7 is adhered thereon.

Next, the manufacturing process of the adsorption pad 8 of this invention comprised as mentioned above is described. Figure 2 is a schematic diagram showing an apparatus and a process for manufacturing a polishing pad for polishing according to the present invention.

First, in the preparation step, the polyurethane resin is dissolved by mixing the polyurethane resin with N, N-dimethylformamide and additives, which are soluble organic solvents. In the polyurethane resin, 100% Modulus is selected from resins such as polyester, polyether, polycarbonate, etc. of about 20 to 40 Kg / cm 2, and dissolved in DMF so that the polyurethane resin is 20%. As an additive, in order to adjust the size and density of the foaming cell 3, pigments such as carbon black, a hydrophilic activator for promoting foaming, a hydrophobic activator for stabilizing solidification of the polyurethane resin, a fluorine-modified polyurethane resin for improving water repellency, and the like can be used. Can be. The resulting solution is filtered to remove impurities and the like, to obtain a polyurethane resin solution of 10,000 to 20,000 cps having a suitable viscosity that can be degassed under vacuum and introduced into a wet process.

The polyurethane resin solution flows out of the solution tank 21 and is applied onto the film forming film P. That is, the PET film roll used as the film forming substrate is released from the unwinder 20 and moved by each roll, and the polyurethane resin solution flowing out of the solution tank 21 in front of the knife coater 23 is the film. It is applied onto and homogenized by the knife coater 23. The polyurethane-coated film was then moved by a roll to solidify through a coagulation bath 25 filled with a coagulant liquid containing water, which is an insoluble solvent, as a main component of the polyurethane resin. The water is washed through a washing tank 29 filled with a washing liquid such as water and then dried through a drying tenter 30 which is a drying chamber for drying the foamed polyurethane sheet. The coating, coagulation, washing and drying processes are performed sequentially by a device installed in conjunction with each other.

In the coagulation bath 25, an interlocking turning roll 24 is disposed at the inner bottom. A mangle roller 26 is provided between the coagulation tank 25 and the water washing tank 29 to dehydrate the water penetrated into the polyurethane resin after coagulation after the coagulation tank 25. In the water washing tank 29, five guide rolls 27 at the top and four at the bottom in the same vertical direction as the transfer direction of the film-forming film P are provided so as to cross up and down. In the upper part of the water washing tank 29, the mangle roller 28 which dehydrates the polyurethane sheet after water washing is arrange | positioned. In the next step, a drying tenter 30 for drying the foamed polyurethane sheet is interlocked and a rewinder 31 is wound around the foamed polyurethane sheet 1. The film forming film P is transferred from the unwinder 20 to the rewinder 31 by the interlocking driving force. Although the feed rate of the film-forming film P was set to 1.5 m / min in this embodiment, Preferably it can be set in the range of 1.0-5.0 m / min. The speed is a range in which the polyurethane sheet is formed and each of the processes can be performed smoothly.

Meanwhile, as shown in FIG. 2, in the coating step, the polyurethane resin solution prepared in the preparation step flows out from the solution bath 21 at room temperature, and is transferred to the film forming film P by the knife coater 23 on the back up roll 22. Evenly applied. In the solidification process, the film-forming film P coated with the polyurethane resin solution is obtained in the coagulation tank 25 by the knife coater 23. In the coagulation bath 25, the surface layer 2 of several micrometers in thickness is formed in the surface of the apply | coated polyurethane resin solution first. Thereafter, the coated polyurethane resin solidifies while maintaining a constant thickness as the substitution reaction between the DMF in the polyurethane resin solution and the coagulating solution in the coagulation bath 25 proceeds. Solidification of this polyurethane resin is completed between the film-forming film P to which the polyurethane resin solution was apply | coated in the coagulating liquid, and until it reaches the mangle roller 26. FIG. When the DMF desolvates from the polyurethane resin solution, a foam layer is formed in the polyurethane resin. At this time, since the film-forming film P of the P.E.T film does not penetrate water, desolvent occurs from the surface side of the polyurethane resin solution, and small foaming cells 3 'and large foaming cells 3 are formed from the surface side. The solidified foamed polyurethane sheet proceeds from the coagulation solution, and after the excess coagulation solution exits the mallet roller 26, is transferred to the washing tank 29 and brought into the washing liquid.

In the water washing and drying step, the polyurethane resin is washed with water by passing the expanded polyurethane sheet carried in the washing liquid up and down through the guide roller 27. After washing with water, the foamed polyurethane sheet is transferred from the water washing tank 29, and the excess washing liquid comes out of the mangle roller 28. Thereafter, the foamed polyurethane sheet is dried while passing through a drying tenter 30. The foamed polyurethane sheet after drying is wound on a rewinder 31 together with the film forming film P.

In the buff polishing treatment step (not shown), the surface layer B of the polyurethane sheet 1 after drying is subjected to the buff polishing treatment. The foamed polyurethane sheet 1 wound on the rewinder 42 is formed on the P.E.T film of the film forming film P. Since film | membrane produces the dispersion | variation in the thickness of the foamed polyurethane sheet 1 at the time of film-forming, the fine unevenness | corrugation by the foamed layer formed in the surface layer B protrudes. As shown in FIG. 1B, the entire foamed polyurethane sheet surface layer B is buff polished without peeling the film forming film P to completely protrude the foamed cells 3 and 3 'formed therein to the outside. The surface buff polished surface B 'is formed. As a result, as shown in FIG. 1, the thickness variation of the polyurethane sheet 1 in which the surface layer B is buff polished and the flat adsorption surface G is formed is eliminated. Thereafter, the base P.E and T films are peeled off and the peeled surface is taken as the adsorption surface G. By doing so, the thickness variation is eliminated to the back surface buff polished on the already formed flat adsorptive surface, and the adsorptive surface formed without water contact retains the viscosity of the polyurethane as it is, and has excellent adsorption power in connection with the formed ultrafine foam layer of the sealed type. Will be displayed.

In the laminating process as shown in FIG. 1C, the support layer 5 of the new P.E.T film is attached to the buff polished surface B 'side of the buff polished foamed polyurethane sheet 1. On the support layer 5, a double-sided tape on which the release paper layer 7 is attached is attached. After cutting to the required standard in the cutting process, the inspection pad is checked to confirm that there is no adhesion of contamination and foreign substances, etc. to complete the adsorption pad 8.

Next, the action | action of the adsorption pad manufactured by this embodiment, etc. are demonstrated.

In this adsorption pad, the polyurethane sheet 1 is subjected to buff polishing on the back side B of the adsorption surface G after wet film formation. By buffing the fine surface irregularities formed in the wet film forming process, a part of the foam layer formed inside the foamed polyurethane sheet is projected to the surface, thereby eliminating the overall thickness variation of the foamed polyurethane sheet. In addition, since the surface in contact with the P.E.T film used as the substrate in the wet process is separated and used as the adsorption surface, the thickness accuracy of the foamed polyurethane sheet 1 is improved together with the adsorption surface G having micro flatness. As a result, the difference between the maximum thickness and the minimum thickness can be adjusted to a thickness average value of 2.0% or less. Since the adsorption pad is excellent in the adsorption property of a to-be-polished object, it can reliably adsorb | suck to a large to-be-polishing object, especially the glass substrate for a large liquid crystal display.

In the general wet film formation method used in the preparation of the adsorption pad, the variation of the thickness of the coated polyurethane resin solution occurs because the variation of mechanical interlocking speed and mechanical vibration occurs when the viscous polyurethane resin solution is applied to the film formation substrate. Occurs. In this state, since the polyurethane resin immersed in the coagulating liquid solidifies, a thickness deviation is formed in the obtained expanded polyurethane sheet. In the coagulation solution, DMF used as a solvent dissolves in the coagulation solution, which is the main component of water, and the coagulation solution penetrates into the polyurethane resin solution. In the bath, the polyurethane resin comes into contact with water to solidify and form a cell therein. In this process, the solidification process of polyurethane resin due to dissolution between water and DMF is uneven due to coating thickness variation, mechanical shaking, non-uniform penetration of coagulating solution, and other conditions. May be increased. In the adsorption pad using the foamed polyurethane sheet having the thickness deviation as it is, since the pressure applied to the polished object is increased at the portion having a high thickness, the processing surface of the portion is greatly polished and the polishing performance is lowered. In order to reduce the thickness variation, the surface of the adsorption pad is buff polished to protrude the cells formed thereon to be used as the adsorption pad. However, since the surface layer effective for adsorption of the polishing object is lost, there is no adsorption of the abrasive. When used as an adsorption pad, a support device for supporting a separate abrasive material is required. In order to solve this problem, adsorption pads have been developed that are used as adsorption surfaces without buffing the skin layer.However, the surface layer used as adsorption surfaces is a surface formed during the initial solidification process by contact with a coagulant containing water as the main component. Viscosity inherent in urethane resin is largely lost, and the adsorption force is lowered. In addition, the thickness deviation was adjusted by buffing the back surface, but due to the surface thickness variation formed during the solidification process and the fine unevenness of the skin layer formed due to the internal non-uniform size cells formed during solidification, the processing resulted in the thickness variation of the suction pad. The flatness of the surface is lowered, but the adsorption pad according to the present embodiment can solve this problem.

Hereinafter, the present invention will be described in more detail with examples.

Example 1

100% Modulus 30Kg / ㎠ by blending 100% Modulus 20Kg / ㎠ polyester type polyurethane resin and 100% Modulus 40Kg / ㎠ polyester type polyurethane resin 50/50 The polyurethane solution of 30% of polyurethane resin adjusted to the solvent and 70% of solvent DMF was used. To 100 parts of this polyurethane resin solution, 15 parts of DMF dispersion for viscosity adjustment, 15 parts of DMF dispersion containing 30% of carbon black as pigment, and polyoxypropylated glycerine / silicon glycol copolymer 2 parts of silicon glycol copolymer (70/30), 0.5 parts of isoparaffine, a coagulation stabilizer, sodium dioctyl sulfossucinate / Isopropyl alcohol (80 / 20) Three parts and a fluorine-modified polyurethane resin were blended in an appropriate amount, mixed, and degassed to prepare a polyurethane resin solution. When the polyurethane resin solution was applied, the coating gap was 2.20 mm. In order to improve the washing | cleaning effect in a washing process, the washing | cleaning after coagulation | solidification was performed in 50 degreeC warm water. The foamed polyurethane sheet (FIG. 3A) was buffed and polished on the B side using sand paper (180) to obtain the expanded polyurethane sheet (FIG. 3) B. Next, the adsorption pad (FIG. 3c) was prepared by attaching the support layer 5 of the P.E.T film to the buffing-treated B 'surface, attaching the double-sided adhesive tape 6 with the release paper layer 7 to the support layer 5, and removing the film forming film P.

Example 2

The adsorption pad of FIG. 4 was prepared like Example 1 except having mixed 5 parts of sodium dioctyl sulfosuccinate / isopropyl alcohol (80/20) as a cell regulator.

Example 3

The adsorption pad of FIG. 5 was prepared like Example 1 except mixing 7 parts of sodium dioctyl sulfosuccinate / isopropyl alcohol (80/20) as a cell regulator.

Comparative example

In the same manner as in Example 1, in the wet process, an adsorption pad was prepared in which the surface layer formed while being in direct contact with the coagulation liquid became the adsorption surface G.

Experimental Example

The surface flatness of the adsorption surface, which is the surface to be polished, of the adsorption pads prepared in each of Examples and Comparative Examples, and the adsorption force, the compression ratio, and the compression modulus of the workpiece were measured.

First, the surface flatness was attached to the glass plate on the adsorption surface and compared visually how evenly the adsorption state of the glass is adsorbed.

The adsorption power of the polished material was measured by the following method. Also shown in the attraction force measuring device shown in Figure 6 is attached to the adhesive tape surface of the suction pad 8, the suction pad to the stainless plate 11, the surface flat and notgoseo the glass plate 12 in the transverse 5cm × vertical 5cm on the attracting surface of the attracting pad thereon 80g Place a 2 kg weight 13 so that a / cm 2 load is applied. After 1 minute, remove the weight 13 and pull the glass plate horizontally to measure the tension when the glass plate 12 moves. Measure The measurement is carried out 10 times to calculate the average value to evaluate the adsorption force of the adsorption pad on the polished object. When adhering the glass plate to the surface of the surface to be adhered and sprayed together, the adsorption performance of the adsorption pad with and without water spray was also evaluated and shown in Table 1 below.

Compression ratio and compression elastic modulus were measured by the following method. Take 3 x 3cm specimens of each of the adsorption pads of each example, stack the 3 specimens and place them for 1 minute at 50grf / cm2 of initial load, and measure the initial thickness using a dial gauge ( T0) Next, after leaving for 1 minute at a load of 300 grf / cm 2, the thickness after pressing in a pressurized state is measured (T1). Next, after removing the load and leaving for one minute, the thickness is measured after standing for one minute at an initial load of 50 grf / cm 2 again (T0 '). These numerical values were applied to the following calculation formulas (1) and (2) to calculate the compression ratio and the extruded elastic modulus, and are shown in Table 2 as three average values.

Compression Ratio (%) = (T0-T1) / T0 × 100 --- (1)

Compression Modulus (%) = (T0'-T1) / (T0-T1) × 100 --- (2)

Table 1

Adsorption force (kgf) Without water spray Water spray Example 1 33.4 34.5 Example 2 33.5 34.7 Example 3 33.6 35.0 Comparative example 12.8 32.5

TABLE 2

Film status Finished product status Compression Ratio (%) Compression modulus (%) Compression Ratio (%) Compression modulus (%) Example 1 4.59 91 2.08 90 Example 2 5.32 92 2.33 91 Example 3 6.04 92 2.75 92 Comparative example 5.52 92 2.36 86

In addition, the thickness of the polyurethane sheet of the adsorption pads prepared according to Examples 1 and 2, the length and width of the cell, and the thickness of the ultrafine foam layer were measured, respectively, and the results are shown in Table 3 below.

TABLE 3

Thickness of polyurethane sheet Cell length The width of the cell Thickness of micro foam layer Example 1 1120 930 105 190 Example 2 1200 1060 118 140

As shown in Tables 1 and 2, the adsorption pad of the comparative example shows a non-uniform adsorption of the polished material, and the adsorption force at this time is 12.8 kgf, which is remarkably higher than that of 32.5 kgf when water was sprayed. It shows weak adsorption force. As a result, it can be seen that the adsorption pad of the comparative example can be used by spraying water on the adsorption surface of the polishing pad or the adsorption pad before adsorption. On the other hand, the adsorption pad of Example 2 has a similar compression ratio to that of the comparative example, and the adsorption force of the polished material is very uniform regardless of the presence or absence of water spray, and the adsorption power of 33.5 kgf and 34.7 kgf is very good. The adsorption pad of Example 1 shows almost the same adsorption force as in Example 2, but due to the lack of the amount of the cell regulator, the cell properties in the foamed polyurethane sheet are relatively small, and the ultrafine foam layer 4 becomes thicker to form a rubber sheet. The compressibility becomes low and high flatness after polishing cannot be expected. In the adsorption pad of Example 3, the adsorption force to the abrasive was similar to that of Example 2, but the cell phase was relatively increased in the foamed polyurethane sheet by using an excessive amount of cell modifier, and the ultrafine foam layer 4 was thinned to be relatively high. As the compression ratio increases, the adsorption force becomes more excellent, but cell-like afterimages appear on the adsorption surface G, so that the precision flatness after polishing of the polished material is not as expected. In conclusion, it was proved that having the appropriate microfoam layer 4 and the appropriate cell size such as the adsorption pad of Example 2 had the best adsorption force and the excellent flatness of the adsorption surface as the adsorption pad.

The adsorption pad of the present invention configured as described above is a microfiber of sealing type separated from the PET film used as the substrate by buffing the outer skin layer having unevenness formed by contact with water of the foamed polyurethane sheet to have almost uniform thickness. Since the surface formed without direct contact with the water containing the micro-foaming layer is used as the adsorptive surface, the adsorptive surface has the fine flatness of the PET film, which not only maximizes the polishing efficiency for the polished object. By semi-permanently maintaining the viscosity of the polyurethane thus obtained, it is possible to obtain the effect of eliminating the steps of installing a support device for a separate polishing object, water spraying and the like. In addition, by fundamentally blocking the penetration of the polishing liquid into the adsorption pad, it is possible to obtain an effect of improving the life of the adsorption pad more than twice as compared to the existing adsorption pad.

Claims (7)

delete delete 1) preparing a polyurethane resin solution by dissolving the polyurethane resin in a soluble organic solvent and then mixing the additives; 2) applying the polyurethane resin solution continuously to a uniform thickness on a film of the substrate; 3) solidifying the film coated with the polyurethane resin solution in a coagulation bath, and washing with water in a water bath; 4) drying the washed coated film; 5) buffing the surface of the dried coated film; And 6) A method for manufacturing a polishing pad comprising the step of attaching a support layer (5) to the buffing surface and removing the base film. The method of claim 3, wherein the organic solvent for dissolving the polyurethane resin is N, N-dimethylformamide (DMF). The method of claim 3, wherein the polyurethane resin is selected from a polyester, polyether, and polycarbonate resin having 100% Modulus of about 20 to 40 kg / cm 2. . The method according to claim 3, wherein sodium dioctyl sulfossucinate / isopropyl alcohol (80/20) is 3 parts by weight to 7 parts by weight as a cell regulator with respect to 100 parts by weight of the polyurethane resin solution. A method for producing a polishing pad, characterized in that the weight part to be contained. The method of claim 3, wherein the additive is a pigment such as carbon black, a hydrophilic active agent, a hydrophobic active agent, or a fluorine-modified polyurethane resin.

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