KR101608119B1 - Polishing pad - Google Patents

Abstract

The present invention relates to a polishing pad excellent in moisture resistance and water resistance and a method for producing the same. Exemplary polishing pads can secure an excellent adhesive force between the polishing layer and the pressure-sensitive adhesive layer even in a polishing process under a humid atmosphere or an aqueous environment, for example, by a polishing liquid.

Description

Polishing pad {POLISHING PAD}

The present application relates to a polishing pad and a method of manufacturing the same.

In the manufacture of automobiles, optical devices, semiconductors, etc., a polishing process may be performed on various components. For example, a hard disk substrate, an optical lens, a silicon wafer, or the like can be polished.

For example, a glass substrate, which is one of components of an LCD (Liquid Crystal Display), may be polished. A glass substrate can be used as a color filter substrate or a TFT (Thin Film Transistor) substrate of an LCD, and the surface smoothness of the glass substrate needs to be ensured.

The glass substrate may be manufactured by, for example, a fusion or a floating method. In the floating system, a glass substrate can be manufactured while injecting a raw material melted in a melting furnace into a horizontal roller. In the floating system, for example, a process of polishing the glass in a post-process may be required because the glass may be bent in the process of contacting the roller.

The polishing pad used in the polishing process usually includes an abrasive layer and a pressure-sensitive adhesive layer adhered to one surface of the abrasive layer. In this case, when a pressure is applied while maintaining elasticity, the pressure-sensitive adhesive exhibits a wetting phenomenon on an adherend, for example, the polishing layer, so that it exhibits resistance to peeling force or shearing force and can induce adhesion at the interface. In order for the pressure-sensitive adhesive to perform the above-described role efficiently, it is required to exhibit excellent wettability and appropriate cohesive force and peel resistance. Further, since the polishing pad is generally exposed to a high humidity or an aqueous environment by an abrasive liquid or the like in a polishing process, the pressure-sensitive adhesive applied to the polishing pad may be required to have moisture resistance or water resistance.

The present application provides a polishing pad and a method of manufacturing the same.

An exemplary polishing pad of the present application may include a polishing layer and a pressure-sensitive adhesive layer adhered to one surface of the polishing layer. The pressure-sensitive adhesive layer may comprise an acrylic polymer and an isocyanate compound. In the pressure-sensitive adhesive layer, the acrylic polymer may have a crosslinking structure together with the crosslinking agent, and the isocyanate compound may be contained in the pressure-sensitive adhesive layer in a state of not reacting with the crosslinking structure. In another example, the pressure sensitive adhesive layer may comprise a polyurea derived from the isocyanate compound. Such a polyurea can be formed, for example, by reaction between water molecules or moisture introduced from the external environment and the isocyanate compound when the polishing pad is exposed to an aqueous environment or a high humidity environment. Accordingly, the gel content of the pressure-sensitive adhesive layer before and after exposure to the aqueous or high-humidity environment can be changed.

The polishing pad can be used, for example, in the process of polishing the surface of various parts or members of an automobile, an optical instrument, or a semiconductor field. Examples of objects to be polished include glass substrates for LCDs, substrates for hard disks, optical lenses, silicon wafers, and the like, but are not limited thereto. In one example, the subject to be polished is, for example, a glass substrate, and may be a glass substrate having a large area, for example, seven generations or eight generations or more.

The polishing layer included in the polishing pad may be a polishing layer known in the art without any particular limitation. For example, as the polishing layer, a polishing layer made of a polyurethane polishing layer, for example, a hard polyurethane or a polyurethane porous foam may be used.

The polishing pad may further comprise a cushion layer. The material and position of the cushion layer are not particularly limited, and for example, a known cushion layer made of foamed polyurethane or the like may be present in the form of being laminated or attached on one side of the abrasive layer.

The thickness of the abrasive layer is not particularly limited, and can be adjusted to an appropriate thickness in consideration of the object to be polished in an actual polishing process. Typically, the abrasive layer may have a thickness of, for example, 0.5 mm to 4 mm, 0.8 mm to 3 mm, or 1 mm to 2 mm, but is not limited thereto.

The polishing layer may be in direct contact with the object to be polished in the polishing step, and a surface in contact with the object to be polished may have a lattice-like, circular, or spiral-shaped groove structure.

The pressure-sensitive adhesive layer may comprise an acrylic polymer and an isocyanate compound or may comprise a polyurea derived from the isocyanate compound. In one example, the isocyanate compound may be included in the pressure-sensitive adhesive layer in a proportion of 0.5 part by weight or more based on 100 parts by weight of the acrylic polymer. Unless otherwise specified, the unit weight portion in the present specification may mean a weight ratio between the respective components. In another example, the isocyanate compound may be contained in an amount of 0.7 parts by weight or more, 0.8 parts by weight or more, 0.9 parts by weight or more, or about 0.95 parts by weight or more, based on 100 parts by weight of the acrylic polymer. The upper limit of the ratio of the isocyanate compound is not particularly limited. For example, 10 parts by weight or less, 8 parts by weight or less, 6 parts by weight or less, 4 parts by weight or less, or 3 parts by weight ≪ / RTI > In the present specification, the ratio of the isocyanate compound in the pressure-sensitive adhesive layer may be a ratio of the isocyanate compound present before the polyurea is formed, for example, before the polishing pad is exposed to the aforementioned water-based or high-humidity environment. Therefore, when the polyurea is formed in the pressure-sensitive adhesive layer, the ratio may be lower than the above-mentioned ratio, and this case is not excluded from the polishing pad. The proportion of the isocyanate compound before the polyurea is formed can be predicted in consideration of the proportion of the polyurea and the like even in the state where the polyurea is formed.

The kind of acrylic polymer contained in the pressure-sensitive adhesive layer is not particularly limited, and for example, all kinds of polymers known as pressure-sensitive adhesive resins that can be used in the production of pressure-sensitive adhesives can be used. For example, as the acrylic polymer, a polymer containing a (meth) acrylic acid ester monomer and a copolymerizable monomer having a crosslinkable functional group can be used. The monomers may be polymerized with each other, for example, and incorporated in the polymer. The term " copolymerizable monomer having a crosslinkable functional group " as used herein includes both a crosslinkable functional group and a copolymerizable functional group so as to form a polymer by polymerizing with another monomer such as a (meth) acrylic acid ester monomer, May refer to a monomer capable of providing a functional group.

As the (meth) acrylic acid ester monomer, for example, alkyl (meth) acrylate can be exemplified. Considering the physical properties of the pressure-sensitive adhesive layer, for example, alkyl (meth) acrylates containing an alkyl group having 1 to 14 carbon atoms can be used. Examples of the monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, (Meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, pentyl But are not limited to, one or more of octyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate or tetradecyl (meth) acrylate.

The type of the copolymerizable monomer having a crosslinkable functional group contained in the acrylic polymer is not particularly limited as long as it has a crosslinkable functional group and a copolymerizable functional group as described above. In the production of pressure-sensitive adhesives, a variety of such copolymerizable monomers are known, and such monomers can be freely selected. As the copolymerizable monomer, an acrylic polymer having a crosslinkable functional group of a kind which does not react with the above-described isocyanate compound may be used. That is, the acrylic polymer may not contain a functional group that reacts with the isocyanate compound. In this state, the polymer can, if necessary, realize a crosslinked structure through reaction with a crosslinking agent described later. In addition, the isocyanate compound may be present in the pressure-sensitive adhesive layer in a state not participating in the formation of the crosslinked structure, and thus the moisture resistance or water resistance of the pressure-sensitive adhesive may be improved. As such a copolymerizable monomer, a copolymerizable monomer having a carboxyl group as a crosslinkable functional group may be exemplified. Such monomers are known in the art and include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, monomethyl maleic acid, isoprenesulfonic acid, styrenesulfonic acid and 5-norbornene- Acid, and the like, but are not limited thereto.

The acrylic polymer may include 90 to 99.9 parts by weight of the (meth) acrylic acid ester monomer and 0.1 to 10 parts by weight of the copolymerizable monomer. However, the above ratios can be changed as needed.

In addition to the above, the acrylic polymer may further contain, if necessary, various copolymerizable monomers known in the art in an appropriate ratio.

The acrylic polymer may have a weight average molecular weight (Mw) of, for example, from 400,000 to 2,000,000 or from 600,000 to 1,200,000. The term "weight average molecular weight" as used herein means a value converted to standard polystyrene measured by GPC (Gel Permeation Chromatograph), and unless otherwise specified, the term molecular weight may mean weight average molecular weight. When an acrylic polymer having a molecular weight in the above range is used, the pressure-sensitive adhesive layer can exhibit excellent durability, moisture resistance, water resistance and adhesiveness.

The acrylic polymer may be obtained by polymerizing a mixture containing monomers to be polymerized in accordance with a desired composition, for example, by solution polymerization, photopolymerization, bulk polymerization, suspension polymerization or emulsion polymerization Can be manufactured.

The isocyanate compound contained in the pressure-sensitive adhesive layer can contribute to improvement of the water resistance or moisture resistance of the pressure-sensitive adhesive layer. As the isocyanate compound, an isocyanate compound having three or more isocyanate groups can be used. The number of isocyanate groups contained in the isocyanate compound may be, for example, 10 or less, 9 or less, 8 or less, 7 or less, 6 or less or 5 or less. The isocyanate compound may have a molecular weight of 10,000 or less, 7,000 or less, or 5,000 or less. Here, the molecular weight refers to the general molecular weight of the compound, not the weight average molecular weight. By using the isocyanate compound as described above, it is possible to form a pressure-sensitive adhesive layer having excellent water resistance and moisture resistance. The lower limit of the molecular weight of the isocyanate compound is not particularly limited, and may be, for example, about 100, 120, 140 or 170.

The kind of the isocyanate compound is not particularly limited and includes, for example, a reaction product of a diisocyanate compound and a polyol (for example, trimethylol propane), an isocyanurate adduct of a diisocyanate compound, Isocyanurate trimer, triisocyanate phenylthiophosphate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, or 4,4 ', 4 "-tris Triphenylmethane triisocyanate, and the like can be exemplified. Examples of the diisocyanate compound include toluene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoboron diisocyanate, tetramethylxylene diisocyanate, and naphthalene diisocyanate. It is not.

The isocyanate compound may be contained in the pressure-sensitive adhesive layer in a proportion of, for example, 0.5 parts by weight or more, 0.7 parts by weight or more, 0.8 parts by weight or more, 0.9 parts by weight or more, or about 0.95 parts by weight or more based on 100 parts by weight of the acrylic polymer. If the proportion of the compound is too low, appropriate moisture resistance and water resistance may not be secured in the pressure-sensitive adhesive layer. The upper limit of the ratio of the isocyanate compound is not particularly limited. For example, 10 parts by weight or less, 8 parts by weight or less, 6 parts by weight or less, 4 parts by weight or less, or 3 parts by weight ≪ / RTI > As described above, the ratio means the ratio before the polyurea is formed in the pressure-sensitive adhesive layer. These ratios can be predicted from the state where no polyurea is formed in the pressure-sensitive adhesive layer, or from the amount of the remaining isocyanate compound and the polyurea formed when the polyurea is formed.

The pressure-sensitive adhesive layer may further include a crosslinking agent. The crosslinking agent may be used without limitation as long as it can crosslink the acrylic polymer as the adhesive resin. As the crosslinking agent, for example, an epoxy crosslinking agent or an aziridine crosslinking agent may be used.

Examples of the epoxy crosslinking agent include ethylene glycol diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, N, N, N ', N'-tetraglycidylethylenediamine or glycerin diglycidyl ether And aziridine crosslinking agents may be exemplified by N, N'-toluene-2,4-bis (1-aziridinecarboxamide), N, N'-diphenylmethane- , 4'-bis (1-aziridine carboxamide), triethylene melamine, bisisopropanoyl-1- (2-methyl aziridine), or tri-1-aziridinyl phosphine oxide But is not limited thereto.

The crosslinking agent may be contained in the pressure-sensitive adhesive layer at a ratio of 0.5 to 15 parts by weight based on 100 parts by weight of the acrylic polymer, and the cohesive force and durability of the pressure-sensitive adhesive can be appropriately maintained.

The pressure-sensitive adhesive layer may further comprise 1 to 100 parts by weight of a tackifier for 100 parts by weight of the acrylic polymer. Examples of the tackifier include a hydrocarbon resin or hydrogenated product thereof, a rosin resin or hydrogenated product thereof, a rosin ester resin or hydrogenated product thereof, a terpene resin or hydrogenated product thereof, a terpene phenol resin or hydrogenated product thereof, Polymerized rosin ester resin, and the like, or a mixture of two or more of them may be used, but the present invention is not limited thereto. In addition, desired physical properties can be effectively imparted to the pressure-sensitive adhesive within the above range.

The pressure-sensitive adhesive layer may have a gel content in a different range, for example, before and after the polyurea is formed. In one example, a higher gel content may be exhibited after the polyurea is formed. For example, when the ratio (GW / G) of the gel content (GW) measured after immersing the pressure-sensitive adhesive layer in water at 70 ° C for 24 hours and the gel content (G) of the pressure- Lt; / RTI > In another example, the lower limit of the ratio (GW / G) of the gel content (GW) of the pressure-sensitive adhesive layer may be 1.1 or more, 1.2 or more, 1.3 or more, 1.4 or 1.5 or more, and the upper limit may be 2.5 or less, But is not limited thereto. The gel content (G) of the pressure-sensitive adhesive layer before immersion in water is the gel content in the state where the polyurea component is not substantially formed in the pressure-sensitive adhesive layer, and may be, for example, about 5% to 90%. On the other hand, the gel content (GW) measured after immersing in water at 70 ° C for 24 hours may be, for example, 5.05% to 90.05% or 90.05% or more.

The gel content can be calculated by the following equation (1).

[Equation 1]

Gel content = B / A x 100

In the formula (1), A represents the mass of the pressure-sensitive adhesive layer, and B represents the dry weight of the insoluble fractions recovered after immersing the pressure-sensitive adhesive layer of the mass A in ethyl acetate at room temperature for 48 hours. The drying conditions for measuring the dry mass of the insoluble fractions are not particularly limited and may be carried out under conditions that the ethyl acetate as the solvent introduced by the deposition can be substantially removed.

As used herein, the term ambient temperature refers to the temperature at which the natural temperature is not warmed or attenuated, for example, about 15 占 폚 to 35 占 폚, about 20 占 폚 to 25 占 폚, about 25 占 폚, or about 23 占 폚 .

It is possible to provide a polishing pad which maintains the gel content of the pressure-sensitive adhesive layer at the above-mentioned ratio to provide excellent adhesion to a polishing layer such as a polyurethane polishing layer and to maintain excellent moisture resistance and water resistance.

The present application also relates to a polishing method using the polishing pad. The polishing pad may be used in a conventional polishing process for polishing a workpiece. In particular, the polishing pad can be suitably performed when the polishing process is performed in an aqueous or high-humidity condition.

For example, the polishing method may include a step of polishing the workpiece in an environment in which moisture is present using the polishing pad. The polishing step may be, for example, a hard disk substrate, an optical lens, a silicon wafer, or the like, and the specific process conditions and the like are not particularly limited as long as the polishing pad is used.

Since the polishing process proceeds in an environment in which moisture is present, the gel fraction of the pressure-sensitive adhesive layer may change through the generation of the aforementioned polyurea before and after the polishing process. For example, the ratio (GW / G) of the gel content (G) of the pressure-sensitive adhesive layer before the polishing process to the gel content (GW) of the pressure-sensitive adhesive layer after the polishing process may be 1.05 to 3. In another example, the lower limit of the ratio (GW / G) of the gel content (GW) of the pressure-sensitive adhesive layer may be 1.1 or more, 1.2 or more, 1.3 or more, 1.4 or 1.5 or more, and the upper limit may be 2.5 or less, But is not limited thereto.

The present application also relates to a method of manufacturing a glass substrate.

An exemplary method of fabrication may comprise polishing the surface of the glass substrate using the polishing pad. In one example, the glass substrate may be a glass substrate manufactured in a floating manner. Further, the glass substrate may be a glass substrate for an LCD, such as a color filter substrate or a TFT substrate.

As described above, even when the polishing pad is formed in a large area, the polishing pad can effectively fix the abrasive, and is excellent in resistance to water, abrasive liquid, and the like and resistance to shear force applied in the polishing process. Therefore, according to the manufacturing method using the adhesive tape or the polishing pad, it is possible to effectively polish the surface of a glass substrate having a large area such as, for example, 7th generation or 8th generation.

In addition, a polished glass substrate can be manufactured by polishing the surface of the glass substrate using the polishing pad. The method of manufacturing the glass substrate is not particularly limited as long as the polishing pad is used, and a conventional method can be applied. For example, in the above-described manufacturing method, a glass substrate manufactured by a floating method is loaded on a holder of the polishing apparatus, cerium oxide is dispersed through a nozzle or the like provided on the polishing apparatus by using a polishing pad attached to the carrier It is possible to proceed in a manner of grinding at a proper speed while dispersing the polishing liquid.

In the present application, it is possible to provide a polishing pad excellent in water resistance and moisture resistance by blending a predetermined isocyanate compound in the pressure-sensitive adhesive layer of the polishing pad. The degree of crosslinking of the pressure-sensitive adhesive layer of the polishing pad can be changed according to the external environment, so that the gel content of the pressure-sensitive adhesive layer can be changed.

Hereinafter, the polishing pad will be described in detail through examples and comparative examples, but the scope of the polishing pad is not limited by the following examples.

In this specification, each physical property is evaluated in the following manner.

1. Evaluation of moisture resistance 1

The laminated structure of the polishing pad (polyurethane polishing layer, pressure-sensitive adhesive layer and poly (ethylene terephthalate)) film produced in Examples or Comparative Examples was immersed in water at a temperature of 85 캜 and maintained for about 24 hours. Then, after removing the polishing pad from the water, the moisture resistance was evaluated according to the following criteria while peeling the polishing pad from the PET film.

<Criteria of moisture resistance evaluation 1>

O: When the phenomenon of stretching or tearing of the abrasive layer at the time of peeling is observed

X: When the abrasive layer was peeled from the PET film without being stretched or torn during peeling

2. Evaluation of moisture resistance 2

The laminate structure of the same polishing pad (polyurethane polishing layer, pressure-sensitive adhesive layer, and poly (ethylene terephthalate)) film used in the moisture resistance evaluation 1 was completely immersed in water at 85 캜 for 24 hours. After removing the polishing pad, it was visually observed whether peeling occurred at the interface between the polishing layer and the PET film and evaluated according to the following criteria.

&Lt; Evaluation Criteria of Moisture Resistance 2 >

&Amp; cir &amp;: Peeling was not confirmed at the interface between the abrasive layer and the PET film

DELTA: Peeling was slightly observed at the interface between the abrasive layer and the PET film

X: When the abrasive layer and the PET film were completely peeled off

3. Gel content before immersion in water

About 0.2 g of the pressure-sensitive adhesive layer (A in the formula 1) was taken from the polishing pad prepared in the example or the comparative example, put in a stainless steel mesh, and immersed in ethyl acetate at room temperature for 48 hours. Thereafter, the remaining pressure-sensitive adhesive layer (insoluble portion) which was not dissolved in ethyl acetate was taken out and dried at 100 ° C for 1 hour, and then its mass (B in Formula 1, g) was measured again. Then, each measured value was substituted into Equation 1 to measure the gel content.

4. Gel content after immersion in water

The polishing pad prepared in Example or Comparative Example was immersed in water at a temperature of 70 DEG C for about 24 hours. Thereafter, the polishing pad was taken out from the water, and about 0.2 g of the pressure-sensitive adhesive layer was taken therefrom (A in the formula 1), put into a stainless steel mesh, and immersed in ethyl acetate at room temperature for 48 hours. Thereafter, the remaining pressure-sensitive adhesive layer (insoluble portion) which was not dissolved in ethyl acetate was taken out and dried at 100 ° C for 1 hour, and then its mass (B in Formula 1, g) was measured again. Then, each measured value was substituted into Equation 1 to measure the gel content.

Manufacturing example  1. Preparation of acrylic polymer

Ethyl acetate (EAc) was added as a solvent to 95 parts by weight of 2-ethylhexyl acrylate (2-EHA) and 5 parts by weight of acrylic acid into a reactor equipped with a cooling device so that nitrogen gas was refluxed and temperature- Lt; / RTI &gt; Then, nitrogen gas was purged for about 1 hour to remove oxygen, and solution polymerization was carried out by adding an appropriate amount of a reaction initiator (AIBN (azobisisobutyronitrile)) to obtain a polymer having a molecular weight (Mw) of about 900,000 and a molecular weight distribution (PDI (polydispersity) ) Was about 5.7, and a polymerization solution having a solid content of 48 wt% in the weight of the entire formulation was prepared.

Example  One

Preparation of pressure-sensitive adhesive composition

About 0.38 part by weight of an epoxy crosslinking agent (trimethylolpropane-triglycidylether) and 1.01 part by weight of a trifunctional isocyanate compound (tris (p-isocyanatophenyl) thiophosphate) were added to the polymerization solution prepared in Preparation Example 1 based on 100 parts by weight of the solid content of the polymerization solution , Diluted to a proper concentration with a solvent, and then uniformly mixed to prepare a pressure-sensitive adhesive composition.

Manufacture of polishing pad

The pressure-sensitive adhesive composition thus prepared was coated on one side of the PET film and dried to form a uniform coating layer having a thickness of about 100 탆. The coating layer was then laminated to a conventional polyurethane polishing layer and maintained at a temperature of about 40 DEG C for 48 hours to prepare a polishing pad.

The pressure-sensitive adhesive composition was heated and adhered to a urethane-based pad using a heating laminate to prepare a uranium back pad.

Example  2 and Comparative Example  1 to 3

A polishing pad was prepared in the same manner as in Example 1, except that the composition of the pressure-sensitive adhesive composition was changed as shown in Table 1 below.

Example Comparative Example One 2 One 2 3 Acrylic polymer 100 100 100 100 100 Epoxy cross-linking agent 0.38 0.38 0.38 0.38 0.38 NCO 1 1.01 2.02 - - 0.25 NCO 2 - - - 2.02 - Content Unit: parts by weight (based on solids content)
Epoxy crosslinking agent: trimethylolpropane-triglycidylether
NCO 1: tris (p-isocyanatophenyl) thiophosphate
NCO 2: benzyl isocyanate

The moisture resistance measured in Examples and Comparative Examples are summarized in Table 2 below.

Moisture resistance evaluation 1 Moisture resistance evaluation 2 Gel content before immersion in water Gel content after immersion in water Example 1 ○ ○ 20 30 Example 2 ○ ○ 20 34 Comparative Example 1 × × 20 20 Comparative Example 2 × × 20 20 Comparative Example 3 × × 20 20.1

Claims (20)

Abrasive layer; And
An abrasive layer attached to the abrasive layer; And a pressure-sensitive adhesive layer comprising an isocyanate compound having at least three isocyanate groups in a proportion of not less than 0.5 parts by weight based on 100 parts by weight of the acrylic polymer or a polyurea derived from the isocyanate compound, wherein the acrylic polymer is reactive with an isocyanate compound A polishing pad that does not contain a functional group. The polishing pad of claim 1, wherein the polishing layer is a polyurethane polishing layer. The polishing pad of claim 1, wherein the acrylic polymer has a weight average molecular weight of 400,000 to 2,000,000. The polishing pad according to claim 1, wherein the acrylic polymer contains 90 to 99.9 parts by weight of a (meth) acrylic acid ester monomer and 0.1 to 10 parts by weight of a carboxyl group-containing copolymerizable monomer. delete The composition according to claim 4, wherein the carboxyl group-containing copolymerizable monomers are selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, monomethyl maleic acid, isoprenesulfonic acid, styrenesulfonic acid and 5-norbornene- At least one selected from the group consisting of: The polishing pad of claim 1, wherein the isocyanate compound has a molecular weight of 10,000 or less. The process according to claim 1, wherein the isocyanate compound is selected from the group consisting of a reaction product of a diisocyanate compound and a polyol, an isocyanurate adduct of a diisocyanate compound, triisocyanate phenylthiophosphate, 2,4,6-triisocyanate toluene, 1,3,5- Triisocyanate benzene, and 4,4 ', 4 "-triphenylmethane triisocyanate. The process according to claim 8, wherein the diisocyanate compound is selected from the group consisting of toluene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoboron diisocyanate, tetramethyl xylylene diisocyanate and naphthalene diisocyanate Polishing pad. The polishing pad according to claim 1, wherein the pressure-sensitive adhesive layer further comprises 0.5 to 15 parts by weight of a crosslinking agent based on 100 parts by weight of the acrylic polymer. 11. The polishing pad of claim 10, wherein the crosslinking agent is an epoxy crosslinking agent or an aziridine crosslinking agent. 12. The composition of claim 11, wherein the epoxy cross-linking agent is selected from the group consisting of ethylene glycol diglycidyl ether, triglycidyl ether, trimethylol propane triglycidyl ether, N, N, N ', N'-tetraglycidyl ethylenediamine and glycerine diglyme &Lt; RTI ID = 0.0 &gt; cidyl &lt; / RTI &gt; ether. 12. The method of claim 11, wherein the aziridine crosslinking agent is selected from the group consisting of N, N'-toluene-2,4-bis (1-aziridine carboxamide), N, N'- Aziridine carboxamide), triethylene melamine, bisisopropanoyl-1- (2-methyl aziridine), and tri-1-aziridinyl phosphine oxide. The polishing pad according to claim 1, wherein the pressure-sensitive adhesive layer further comprises 1 to 100 parts by weight of a tackifier, based on 100 parts by weight of the acrylic polymer. The hydrogenation product of rosin resin, rosin ester resin, hydrogenated product of rosin ester resin, terpene resin, hydrogenated product of terpene resin, hydrogenated product of hydrogenated product of hydrogenated product of hydrogenated product of rosin ester resin, A terpene phenol resin, a hydrogenated product of a terpene phenol resin, a polymerized rosin resin, and a polymerized rosin ester resin. The pressure-sensitive adhesive composition according to claim 1, which is obtained by immersing the pressure-sensitive adhesive layer in water at a temperature of 70 캜 for 24 hours and then measuring the gel content (GW) determined by the following formula Polishing pad with a ratio (GW / G) to a gel content (G) of the layer of 1.05 to 3:
[Equation 1]
Gel content = B / A x 100
A is the mass of the pressure-sensitive adhesive layer, and B is the dry mass of the insoluble fractions recovered after immersing the pressure-sensitive adhesive layer of the mass A in ethyl acetate at room temperature for 48 hours. A polishing method comprising a step of polishing a workpiece in an environment in which moisture is present using the polishing pad according to any one of claims 1 to 4 and 6 to 16. The polishing pad according to claim 17, wherein the gel content (G) calculated by the following formula 1 and the gel content (GW) calculated by the following equation 1 of the pressure-sensitive adhesive layer after polishing are respectively Polishing method with a ratio (GW / G) of 1.05 to 3:
[Equation 1]
Gel content = B / A x 100
A is the mass of the pressure-sensitive adhesive layer, and B is the dry mass of the insoluble fractions recovered after immersing the pressure-sensitive adhesive layer of the mass A in ethyl acetate at room temperature for 48 hours. A method of manufacturing a polished glass substrate comprising grinding the surface of the glass with the polishing pad according to any one of claims 1 to 4 and 6 to 16. 20. The method according to claim 19, wherein the glass substrate to be polished is a glass substrate for LCD.