KR20180024096A - Urethane-based prepolymer, polishing pad and preparation method thereof - Google Patents

Abstract

One embodiment relates to a urethane-based prepolymer for manufacture of a polishing pad which is used in a chemical and mechanical planarization process of a semiconductor, to a polishing pad and to a manufacturing method thereof, wherein the urethane-based prepolymer is excellent in storage stability and can control the reaction speed of a raw material mixture (the time during which the mixture is solidified and the gelation time) in the manufacture of the polyurethane polishing pad by having a functional group in itself. Therefore, when the urethane-based prepolymer is used, it is possible to obtain a catalyst having a desired particle size and to easily manufacture a porous polyurethane polishing pad having a pore with a small deviation between upper and lower portions.

Description

[0001] URETHANE-BASED PREPOLYMER, POLISHING PAD AND PREPARATION METHOD THEREOF [0002]

Embodiments relate to a urethane-based prepolymer for polishing pad manufacturing, a porous polyurethane polishing pad, and a method for manufacturing the same, which are used in a chemical mechanical planarization (CMP) process of a semiconductor.

A chemical mechanical planarization (CMP) process during a semiconductor manufacturing process is a process in which a wafer is chemically treated by supplying a slurry, with the wafer being attached to the head and contacting the surface of the polishing pad formed on the platen And the platen and the head are relatively moved while reacting, thereby mechanically flattening the uneven portion of the wafer surface.

The polishing pad is an essential raw material that plays an important role in the CMP process. The polishing pad is generally made of a polyurethane resin and has grooves on the surface for a large flow of the slurry and pores for supporting a fine flow pore.

The pores in the polishing pad can be formed by using a solid phase foam having a void, an inert gas, a liquid material, fibers, or the like, or by generating a gas by a chemical reaction. Among these, the technique of forming the pores by injecting the inert gas is advantageous in that there is no material that remains for pore formation or that is discharged during the CMP process and does not cause a side reaction other than the interaction between the pad, . However, in order to form a pore by injecting an inert gas, it is difficult to control the particle size of the pore (in particular, to control the particle size to 50 μm or less) because the process requires handling of the gaseous material. There is a problem that production yield is lowered because it is difficult to reproducibly obtain a uniform quality.

Conventionally, in order to form a pore having an appropriate size particle diameter by injecting an inert gas, a method of curing the resin before the inert gas becomes larger than a certain size by using a catalyst promoting the reaction was used. As a catalyst promoting the reaction, a tertiary amine or an organic metal is generally used (see Korean Patent No. 10-1385483 and Korean Patent No. 10-0986969).

Korean Patent No. 10-1385483 Korean Patent No. 10-0986969

Korean Patent No. 10-0986969 discloses that a tertiary amine or an organic metal is used as a reaction catalyst in order to form a pore of a proper size in the production of a polishing pad. In this case, the storage stability of the prepolymer is lowered, There has been a problem in that a separate device for injecting the catalyst at the time of adding the catalyst has to be added.

Further, the pores formed by the inert gas dispersed in the resin are so low in the specific gravity as to be compared with the resin that they float in the opposite direction of gravity. At this time, the pores are gradually grown by overlapping or joining with the adjacent pores, There has been a problem that large particle size deviation occurs.

Accordingly, it is an object of the present invention to provide a prepolymer capable of controlling the reaction rate of a raw material mixture in the production of a polyurethane polishing pad, and a method of manufacturing a polishing pad using the prepolymer.

Another object of the embodiment is to provide a porous urethane polishing pad having an appropriately sized pore and a small pore deviation between the upper and lower portions.

In order to achieve the above object,

An isocyanate compound, a polyol, and a reaction rate controlling agent having a carboxyl group,

Based prepolymer having an isocyanate terminal group of 7 to 11%.

In order to accomplish the above other object, another embodiment is a method for manufacturing a porous polyurethane polishing pad, comprising the steps of putting an inert gas at the time of mixing the urethane-based prepolymer and the curing agent as described above to form pores, .

According to another aspect of the present invention,

A porous polyurethane polishing pad comprising a polyurethane resin and pores dispersed in the polyurethane resin,

The polyurethane resin is obtained by reacting the urethane-based prepolymer and the curing agent as described above,

Wherein the pores are formed from an inert gas and have an average particle size of 20 to 50 mu m and a particle size standard deviation of 0.1 to 5.0.

The urethane-based prepolymer according to the present invention is not only excellent in storage stability but also has a functional group in itself, so that the reaction rate of the raw material mixture (the time for solidification of the mixture and the gelation time) can be controlled during the production of the polyurethane polishing pad.

Accordingly, by using the urethane-based prepolymer, it is possible to easily produce a porous polyurethane polishing pad having a pore having a desired size of particle size and a small deviation between the upper and lower portions without using a catalyst.

FIG. 1 is a graph of gelation time change according to the content of carboxyl groups measured in Reference Example.
Fig. 2 is a graph of viscosity change of the urethane-based prepolymer of Example 1 and Comparative Examples 1 and 2 with time. Fig.

Urethane-based Prepolymer

The urethane-based prepolymer of one embodiment is obtained by reacting an isocyanate compound, a polyol, and a reaction rate modifier having a carboxyl group, and has an isocyanate terminal group of 7 to 11%.

The term "prepolymer" generally means a polymer having a relatively low molecular weight in which a degree of polymerization is interrupted at an intermediate stage in order to easily form a final molded product. The prepolymer can be molded on its own or after reacting with another polymerizable compound, for example, by reacting an isocyanate compound with a polyol to prepare a prepolymer.

The urethane-based prepolymer may be obtained by reacting the isocyanate compound and the polyol with a reaction rate regulator of 0.1 to 5% by weight based on the total weight of the urethane-based prepolymer. Specifically, the urethane-based prepolymer may be obtained by reacting a reaction rate regulator of 0.5 to 3% by weight based on the total weight of the urethane prepolymer.

The reaction rate controlling agent may be at least one selected from the group consisting of propionic acid, butyric acid, lactone, isocaproic acid, hexanoic acid, octanoic acid, pentanoic acid and derivatives thereof. Specifically, the reaction rate modifier may be 3-hydroxy-2- (hydroxymethyl) -2-methylpropionic acid, 2,2-bis (hydroxy 2-bis (hydroxymethyl) propanoic acid, 2-hydroxy-2,2-bis (hydroxymethyl) butanoic acid, 2-methylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-ethyl-2-hydroxybutyric acid, 2-hydroxybutyric acid, 2-hydroxybutyric acid, d-arabino-1,4-lactone, 2-hydroxyisocaproic acid, 2-hydroxyhexane May be at least one selected from the group consisting of 2-hydroxyhexanoic acid, 3-hydroxyoctanoic acid and 3-hydroxy-3-methylpentanoic acid. have. More specifically, the reaction rate modifier may be 3-hydroxy-2- (hydroxymethyl) -2-methylpropionic acid.

The isocyanate compound may be selected from, for example, toluene diisocyanate (TDI), naphthalene-1,5-diisocyanate, p-phenylene diisocyanate, Examples of the diisocyanate include diisocyanates such as tolylene diisocyanate, diphenyl methane diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate and isoporone diisocyanate. Lt; RTI ID = 0.0 > isocyanate < / RTI >

The polyol may be at least one selected from the group consisting of, for example, a polyether polyol, a polyester polyol, a polycarbonate polyol, an acryl polyol, and the like. Lt; / RTI > Also, the polyol may have a weight average molecular weight of 300 to 3,000 g / mol.

The chain extender may be reacted with a low molecular weight chain extender in the reaction, and the chain extender may be an alcohol compound, an amine compound or a mixture thereof having a weight average molecular weight of 50 to 300 g / mol. That is, the urethane-based prepolymer may be obtained by reacting the chain extender in the reaction.

The urethane-based prepolymer has an isocyanate terminal group of 7 to 11%. Specifically, the urethane-based prepolymer has an isocyanate terminal group of 7 to 11% and may have a weight average molecular weight of 500 to 3,000 g / mol. More specifically, the urethane based prepolymer has an isocyanate terminal group of 8 to 10%, and may have a weight average molecular weight of 800 to 2,000 g / mol.

The urethane-based prepolymer has a viscosity of 500 to 3,000 cps at 70 캜 and may have a viscosity change rate of 1 to 30% after being maintained at 70 캜 for 15 hours. Specifically, the urethane-based prepolymer has a viscosity of 700 to 2,000 cps at 70 ° C and may have a viscosity change rate of 1 to 15% after being maintained at 70 ° C for 15 hours.

The reaction can be carried out at 75 캜 or lower. Specifically, the reaction may be carried out at 70 to 75 占 폚. When the reaction is carried out within the above range, the side reaction which can not control the degree of reaction is minimized, and a prepolymer having more constant physical properties can be produced.

As an example, the prepolymer may be prepared by using toluene diisocyanate as an isocyanate compound, polytetramethylene ether glycol as a polyol, diethylene glycol as a chain extender, and 3-hydroxy-2- (hydroxymethyl ) -2-methylpropionic acid is used and has an isocyanate terminal group of 7 to 11% polymerized at 75 DEG C or lower.

Porous polyurethane Of the polishing pad  Manufacturing method

According to one embodiment, there is provided a method of manufacturing a porous polyurethane polishing pad, which comprises molding an urethane-based prepolymer and a curing agent as described above in the form of pores while injecting an inert gas.

The curing agent may be at least one of an amine compound and an alcohol compound. Specifically, the curing agent may include at least one compound selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, and aliphatic alcohols. For example, the curing agent may be selected from the group consisting of 4,4'-methylenebis (2-chloroaniline), MOCA, diethyltoluenediamine, diaminodiphenylmethane ( diaminodiphenyl methane, diaminodiphenyl sulphone, m-xylylene diamine, isophorone diamine, ethylenediamine, diethylenetriamine, triethylene But are not limited to, triethylenetetramine, polypropylenediamine, polypropylenetriamine, ethylene glycol, diethyleneglycol, dipropyleneglycol, butanediol, hexanediol hexanediol, glycerine, trimethylolpropane, bis (4-amino-3-chlorophenyl) methane, and the like. It can be more than a species.

The inert gas is introduced into the pore by adding the urethane prepolymer and the curing agent during the reaction. The type of the inert gas is not particularly limited as long as it is a gas that does not participate in the reaction between the urethane-based prepolymer and the curing agent. For example, the inert gas may be at least one selected from the group consisting of nitrogen gas (N ₂ ), argon gas (Ar), and helium (He). Specifically, the inert gas may be nitrogen gas (N ₂ ) or argon gas (Ar).

The inert gas may be added in a volume corresponding to 5 to 60% of the total volume of the urethane-based prepolymer and the curing agent. Specifically, the inert gas may be added in a volume corresponding to 10 to 50%, 20 to 50%, 20 to 40%, or 30 to 40% of the total volume of the urethane-based prepolymer and the curing agent.

The urethane-based prepolymer, the curing agent and the inert gas are substantially simultaneously introduced into the mixing process. As an example, the raw material containing the prepolymer, the curing agent and the inert gas may be put into a mixing head together. The urethane prepolymer and the curing agent are mixed with each other by stirring in the mixing head to initiate the reaction, and the inert gas can be dispersed evenly in the raw material. Also, the stirring may be performed at a rate of 1,000 to 10,000 rpm, or 4,000 to 7,000 rpm. When the stirring speed is within the above range, it is more advantageous that the inert gas is uniformly dispersed in the raw material.

The urethane-based prepolymer, the curing agent and the inert gas may be introduced into the mixing process at a constant rate.

The urethane-based prepolymer and the curing agent may be mixed in a molar equivalent ratio of 1: 0.8 to 1.2, or a molar equivalent ratio of 1: 0.9 to 1.1, based on the molar amount of the respective reactive groups. Here, the "molar number basis of each reactor" means, for example, based on the molar number of isocyanate group of the urethane prepolymer and the molar number of the reactive group (amine group, alcohol group, etc.) of the curing agent. Accordingly, the prepolymer and the curing agent can be supplied at a constant rate in the mixing process by controlling the charging rate so as to be charged per unit time in an amount satisfying the molar equivalent ratio exemplified above.

The inert gas may be supplied at a constant rate during the reaction so that the inert gas can be supplied at a rate such that the inert gas is charged per unit time in an amount satisfying the volume fraction shown above.

The urethane-based prepolymer may contain a carboxyl functional group to control the particle size of pores produced by controlling the reaction rate of the raw material mixture (the time during which the mixture is solidified and the gel time).

The urethane-based prepolymer and the curing agent react with each other after mixing to form a solid polyurethane, which is then formed into a sheet or the like. Specifically, the isocyanate terminal group of the urethane-based prepolymer may react with an amine group, an alcohol group, water, or the like of the curing agent. At this time, the inert gas forms a pore in the raw material without participating in the reaction between the urethane prepolymer and the curing agent.

The urethane-based prepolymer contains a carboxyl functional group so that the particle size of the pores produced by accelerating or retarding the reaction with the curing agent can be adjusted to a desired level. Particularly, when the urethane-based prepolymer contains 0.03 to 1 wt% of carboxyl functional groups based on the total weight, it is possible to realize a pore size of 50 탆 or less which is difficult to form pores using inert gas in a conventional manner , There is an additional advantage that the time required for the pores to float up to overlap with other pores or to merge together can also reduce the deviation in particle size between the upper pore and the lower pore.

The molding may be performed using a mold. Specifically, raw materials (urethane type prepolymer, curing agent, and inert gas) sufficiently stirred in a mixing head or the like can be discharged into a mold to fill the inside of the mold. Further, the reaction between the urethane-based prepolymer and the curing agent is completed in the mold, so that a molded article in the form of a cake in the form of a solid state can be obtained in the shape of the mold. More specifically, a gelation time of 30 to 120 seconds at 70 DEG C may be required in the molding. More specifically, a gelation time of 35 to 70 seconds at 70 deg. C in molding may be required.

Conventionally, a molded article is molded using a mold having a height of 5 to 50 times the thickness of a polishing pad to be finally produced, and then the molded article is sliced at equal thickness intervals to produce a plurality of sheets for a polishing pad at a time. In this case, a reaction retarder may be used as a reaction rate adjusting agent in order to secure a sufficient solidification time. Thus, the height of the mold is set to about 40 to 50 times the thickness of the final polishing pad, . However, the sliced sheets may have a pore size varying depending on the molded position in the mold. That is, in the case of a sheet formed at the bottom of the mold, the sheet formed at the upper portion of the mold has pores having a larger particle size than the sheet formed at the lower portion, while having pores with a minute particle size.

Therefore, in order to have uniform pore size per sheet, it is preferable to use a mold capable of producing one sheet by one molding. For this, according to the manufacturing method of the polishing pad according to an embodiment, it is preferable that the mold does not greatly differ from the thickness of the porous polyurethane polishing pad finally produced. Specifically, the mold may have a height corresponding to 1.2 to 2 times the thickness of the porous polyurethane polishing pad to be finally produced. More specifically, the mold may have a height corresponding to 1.3 to 2 times the thickness of the final polishing pad.

After molding, the molded body obtained from the mold can be appropriately sliced or cut into a sheet for the production of a polishing pad. Specifically, a step of cutting each of the upper and lower ends of the molded body obtained from the mold after the molding may be further performed. More specifically, after the molding, each of the upper and lower ends of the molded body obtained from the mold can be cut. By thus partially removing upper and lower portions having a relatively large deviation of the particle diameter after the production of the molded article, it is possible to further reduce the deviation of the particle diameter. More specifically, each of the upper and lower ends of the molded body may be cut by 1/22 to 3/10, or 1/12 to 1/4 of the total thickness of the molded body.

As a specific example, the mold has a height corresponding to 1.2 to 2 times the thickness of the porous polyurethane polishing pad to be finally manufactured, and the upper and lower ends of the molded body obtained from the mold after the molding are respectively set to 1 / 12 to 1/4.

The manufacturing method may further include a step of machining a groove on the surface after the surface cutting, a bonding step with a lower layer portion, an inspection step, a packaging step, and the like. These processes can be carried out in the manner of a conventional polishing pad manufacturing method.

Porous polyurethane Abrasive pad

According to one embodiment, there is provided a porous polyurethane polishing pad comprising a polyurethane resin and pores dispersed in the polyurethane resin,

The polyurethane resin is obtained by reacting the urethane-based prepolymer and the curing agent as described above,

Wherein the pores are formed from an inert gas and have an average particle size of 20 to 50 mu m and a particle size standard deviation of 0.1 to 5.0.

The porous polyurethane polishing pad is made of a polyurethane resin, and the polyurethane resin is obtained by polymerizing a urethane prepolymer having an isocyanate terminal group by reacting with a curing agent. Therefore, the polyurethane resin includes a monomer unit constituting the urethane-based prepolymer. In addition, the polyurethane resin includes the above-mentioned curing agent. The specific types of the monomer unit and the curing agent constituting the urethane-based prepolymer are as exemplified above in the method of producing the polishing pad.

The polyurethane resin may have a weight average molecular weight of 500 to 3,000 g / mol. Specifically, the polyurethane resin may have a weight average molecular weight (Mw) of 600 to 2,000 g / mol, or 700 to 1,500 g / mol.

The pores are present dispersed in the polyurethane resin. Also, the pores are formed by the injection of an inert gas, and the pores are produced in the form of vapor pores during the process.

The pores have an average particle diameter of 20 to 50 mu m and a particle diameter standard deviation of 0.1 to 5.0. Specifically, the pores may have an average particle size of 20 to 40 μm and a particle size standard deviation of 0.2 to 3.0.

In particular, the pores include pores on the upper and lower surfaces of the porous polyurethane polishing pad, and there may be little difference in average particle size of the pores on the upper surface and the lower surface. Specifically, the porous polyurethane polishing pad includes the pores on the upper surface and the lower surface, respectively, and the difference between the average particle diameters of the pores existing on the upper surface and the pores existing on the upper surface may be 3 탆 or less or 1 탆 or less .

The porous polyurethane polishing pad may comprise 30 to 70% by volume of the pores based on the total volume of the polishing pad. In particular, the porous polyurethane polishing pad may comprise 40 to 60% by volume of the pores based on the total volume of the polishing pad.

The porous polyurethane polishing pad may have a thickness of 1 to 5 mm. Specifically, the porous polyurethane polishing pad has a thickness of 1.5 to 3 mm, or 1.8 to 2.5 mm. < / RTI > When the thickness of the polishing pad is within the above range, the basic physical properties of the polishing pad can be sufficiently exhibited while minimizing the grain size deviation of the upper and lower parts of the pore.

The porous polyurethane polishing pad may have a hardness of 30 to 70 Shore D. Specifically, the porous polyurethane polishing pad may have a hardness of 40 to 60 Shore D.

The porous polyurethane polishing pad may have a specific gravity of 0.6 to 0.9 g / cm 3. Specifically, the porous polyurethane polishing pad may have a specific gravity of 0.7 to 0.85 g / cm 3.

The porous polyurethane polishing pad may have a tensile strength of 100 to 300 kgf / cm 2. Specifically, the porous polyurethane polishing pad may have a tensile strength of 120 to 250 kgf / cm 2.

The porous polyurethane polishing pad may have an elongation of 30 to 300%. Specifically, the porous polyurethane polishing pad may have an elongation of 50 to 200%.

The porous polyurethane polishing pad may have grooves on the surface for mechanical polishing. The grooves may have appropriate depth, width and spacing for mechanical polishing and are not particularly limited.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

[ Example ]

Example  One.

1-1: Urethane-based Prepolymer  Produce

Examples of the polyol include polytetramethylene ether glycol (product of PTG Korea, weight average molecular weight: 1,000), toluene diisocyanate (BASF) as the isocyanate, diethylene glycol , 3-hydroxy-2- (hydroxymethyl) -2-methylpropionic acid (product of GEO) as a reaction rate regulator) Respectively.

The synthesis of the urethane-based prepolymer was carried out by adding polytetramethylene ether glycol, diethylene glycol, 3-hydroxy-2- (hydroxymethyl) -2-methylpropionic acid and toluene diisocyanate to the reactor such that the NCO content was 9.1, (NCO%: 9.1, weight average molecular weight: 1,300, carboxyl group content: 0.5% by weight) was prepared by adjusting the reaction temperature to 70 to 75 ° C so as to minimize the amount of the urethane prepolymer. The inside of the reactor was filled with nitrogen (N ₂ ).

1-2: Of the polishing pad  Produce

In the casting apparatus equipped with the urethane-based prepolymer, the hardener and the inert gas injection line, the prepolymer tank was filled with the prepolymer synthesized in 1-1 above, bis (4-amino-3-chlorophenyl) methane -amino-3-chlorophenyl) methane, manufactured by Ishihara), and argon (Ar) was prepared as an inert gas.

During the casting, argon was set so as to be injected in a volume ratio of 20% of the total volume of the urethane prepolymer and the curing agent. The molar equivalent of the NCO group of the urethane prepolymer and the molar equivalent of the curing agent were set at 1: 1 and a rate of 10 kg / Respectively. The discharged material was injected into a mold having a width of 1,000 mm, a length of 1,000 mm and a height of 3 mm and solidified to obtain a solid-cake-shaped molded article. Then, the upper and lower ends of the molded body were cut to obtain one polishing pad having a thickness of 2 mm.

Reference Example . Depending on the content of carboxyl groups Gelling  Time change

The change in gel time with the carboxyl group content of the urethane prepolymer was measured. Specifically, the time elapsed until the mixed solution, which was prepared by mixing the prepolymer and the curing agent in a 1: 1 amount and stirred at 5,000 rpm, was gelated at 70 ° C was measured. The results are shown in FIG.

As shown in FIG. 1, it was found that the gelation time was shortened with an increase in the carboxyl group content, and it was confirmed that the gelation time required to exhibit the gelation time of 35 to 70 seconds was 0.15 to 0.6% by weight.

Comparative Example  One.

A polishing pad was prepared in the same manner as in Example 1, except that 3-hydroxy-2- (hydroxymethyl) -2-methylpropionic acid was not used in the synthesis of urethane prepolymer.

Comparative Example  2.

(Hydroxymethyl) -2-methylpropionic acid, which is a reaction rate regulator, is not used during the synthesis of the urethane prepolymer, the urethane prepolymer, the curing agent, the inert gas, and the reaction rate controlling agent injection line Except that the product name A1 (tertiary amine compound) of Airproduct was injected at a weight ratio of 0.5% of the total weight of the urethane prepolymer and the curing agent using a casting apparatus equipped with a stirrer, To prepare a polishing pad.

Test Example

The properties of the polishing pads prepared in the above Examples and Comparative Examples were measured according to the following conditions and procedures and are shown in Table 1 below. The prepolymer synthesized in Examples and Comparative Examples was measured for viscosity change with time, and the results are shown in Table 1 and FIG. 2.

(1) Hardness: Shore D hardness was measured, and a load of 5 kg was applied to the hardness meter.

(2) Specific gravity: The mass of the sample was measured by an electronic balance, the sample was immersed in water to measure the volume, and then the mass / volume was calculated.

(3) Pore average particle diameter: 600-fold magnification image was obtained by scanning electron microscope (SEM), and an average value obtained by analyzing individual points of the whole pore with an image analyzer was taken. Based on the obtained averages, the variance of the values obtained by the whole analysis carried out on the image analyzer was taken and the standard deviation of the particle size of the pores was calculated.

(4) Pore density: Data was used for the analysis of the pore size, and the value was obtained as the ratio of the area occupied by the total pores to the total area of the photograph of the square.

(5) Tensile strength: The tensile strength was measured at a speed of 50 mm / min using a universal testing system (UTM) to obtain a maximum strength immediately before fracture.

(6) Elongation: The tensile strength was measured in the same manner as in the measuring method, and the maximum deformation amount immediately before the fracture was measured. The ratio of the maximum deformation amount to the initial length was expressed as a percentage (%).

(7) Gel time: Measured as the time taken until the mixed solution prepared by mixing the prepolymer and the curing agent in a ratio of 1: 1 and stirred at 5,000 rpm at 70 캜.

(8) Viscosity: Viscosity at 70 ° C and viscosity change rate at 70 ° C for 5 minutes using a Brookfield viscometer (DV3T Rheometer from Brookfield) and using a Con & Plate type spindle (CPA-51Z) Were measured.

Comparative Example 1 Comparative Example 2 Example 1 Hardness (Shore D) 55.5 56.1 54.0 Specific gravity (g / cm3) 0.79 0.80 0.79 Pore average particle diameter (占 퐉) 51 35 36.9 Pore size standard deviation (탆) 5.43 1.74 1.98 Pore density (vol%) 48 47 47 Tensile strength (kgf / cm2) 178 181 182 Elongation (%) 125 120 138 Gelation time (70 캜, sec) 80 40 40 The viscosity of the prepolymer (70 DEG C, cps) 1,124 1,150 1,634 Viscosity change rate (%) of the prepolymer 3 80 4

As shown in Table 1, Example 1 using the prepolymer obtained by reacting the reaction rate controlling agent having a carboxyl group showed gelation in a remarkably short time as compared with Comparative Example 1 in which the reaction rate controlling agent was not used, It could be finely adjusted.

On the other hand, in Comparative Example 2 in which a reaction rate controlling agent was added from the outside in the production of a polishing pad, the gelling time and the pore size could be finely adjusted, but a separate apparatus for injecting the reaction rate controlling agent during casting had to be provided. There is a problem that the elongation of the polishing pad becomes lower.

Claims (16)

An isocyanate compound, a polyol, and a reaction rate controlling agent having a carboxyl group,
A urethane-based prepolymer having an isocyanate terminal group of 7 to 11%.
The method according to claim 1,
Wherein the urethane-based prepolymer is obtained by reacting a reaction rate regulator of 0.1 to 5% by weight based on the total weight of the urethane-based prepolymer.
The method according to claim 1,
Wherein the reaction rate regulator is at least one selected from the group consisting of propionic acid, butyric acid, lactone, isocaproic acid, hexanoic acid, octanoic acid, pentanoic acid and derivatives thereof.
The method of claim 3,
(Hydroxymethyl) -2-methylpropionic acid, 2,2-bis (hydroxymethyl) butyric acid, 3-hydroxy-2,2-bis (hydroxymethyl) Propionic acid, 2-hydroxy-2-methylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-ethyl-2-hydroxybutyric acid, , 2-hydroxyhexanoic acid, 3-hydroxyoctanoic acid, and 3-hydroxy-3-methylpentanoic acid.
The method according to claim 1,
Wherein the urethane-based prepolymer is obtained by reacting a chain extender in the reaction,
Wherein the chain extender is an alcohol compound, an amine compound or a mixture thereof having a weight average molecular weight of 50 to 300 g / mol.
The method according to claim 1,
The urethane-based prepolymer has a viscosity of from 500 to 3,000 cps at 70 캜 and a viscosity change rate of from 1 to 30% after maintaining at 70 캜 for 15 hours.
A method for producing a porous polyurethane polishing pad, which comprises molding an urethane-based prepolymer of any one of claims 1 to 6 while mixing inert gas with an inert gas to form pores.
8. The method of claim 7,
Wherein the curing agent is at least one selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, and aliphatic alcohols.
8. The method of claim 7,
Wherein the inert gas is charged in a volume corresponding to 5 to 60% of the total volume of the urethane-based prepolymer and the curing agent.
8. The method of claim 7,
Further comprising the step of cutting said upper and lower ends of a molded body obtained from said mold after said molding is performed using a mold.
11. The method of claim 10,
The mold having a height corresponding to 1.2 to 2 times the thickness of the porous polyurethane polishing pad to be finally produced,
Wherein the cutting cuts each of the upper and lower ends of the formed body by 1/12 to 1/4 of the total thickness of the formed body.
8. The method of claim 7,
Wherein a gelation time of 30 to 120 seconds is required at 70 deg. C in the molding.
A porous polyurethane polishing pad comprising a polyurethane resin and pores dispersed in the polyurethane resin,
Wherein the polyurethane resin is obtained by reacting the urethane-based prepolymer of any one of claims 1 to 6 with a curing agent,
Wherein the pores are formed from an inert gas and have an average particle size of from 20 to 50 mu m and a particle size standard deviation of from 0.1 to 5.0.
14. The method of claim 13,
Wherein the porous polyurethane polishing pad comprises 30 to 70 vol% of the pores based on the total volume of the polishing pad.
14. The method of claim 13,
Wherein the porous polyurethane polishing pad comprises the pores on the top and bottom surfaces, respectively, wherein the difference between the average particle sizes of the pores existing on the top surface and the pores existing on the top surface is not more than 3 탆.
14. The method of claim 13,
Wherein the porous polyurethane polishing pad has a thickness of 1 to 5 mm.

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