JP7302168B2 - Urethane resin composition and polishing pad - Google Patents

Description

The present invention relates to a urethane resin composition and a polishing pad.

Polishing pads using urethane resin compositions are widely used in fields requiring a high degree of surface flatness, such as liquid crystal glass, hard disk glass, silicon wafers, and semiconductors. Among them, in the final polishing, a soft porous body processed by a wet film forming method in which urethane resin diluted with a solvent such as DMF (dimethylformamide) is solidified in water is used (for example, Patent Document 1 ).

The properties required for this porous polishing pad include, for example, a high bulk modulus (=low compressibility) to maintain the flatness of the surface of the workpiece, and a material that suppresses scratches on the surface. and the fineness and uniformity (wet film-forming property) of porous cells responsible for holding slurry (polishing liquid) and stable polishing.

However, the above-mentioned low compressibility, flexibility, and wet film-forming property are contradictory physical properties. As a result, scratches become worse. In addition, when the urethane resin is softened in order to avoid scratches, coagulation in water does not progress rapidly, resulting in a loss of uniformity of the porous cells and destabilization of polishing. Thus, it has been difficult to achieve all the physical properties described above at a high level.

Japanese Patent Application Laid-Open No. 2004-256738

The problem to be solved by the present invention is to provide a urethane resin composition that is excellent in low compressibility, flexibility, and wet film-forming properties.

The present invention is a urethane resin composition containing a urethane resin (X) made from a polyol (a), a polyisocyanate (b), and a chain extender (c) as raw materials, wherein the urethane resin is measured by a pulse NMR measurement method. Provided is a urethane resin composition characterized by having an amorphous phase abundance ratio of (X) in the range of 20 to 50% and a crystalline phase abundance ratio in the range of 20 to 50%. be.

The present invention also provides a polishing pad comprising a porous body made of the urethane resin composition.

The urethane resin composition of the present invention is excellent in low compressibility, flexibility, and wet film-forming properties.

Therefore, the urethane resin composition of the present invention can be suitably used as a polishing pad for finish polishing having a porous body obtained by a wet film-forming method.

The urethane resin composition of the present invention contains a polyol (a), a polyisocyanate (b), and a urethane resin (X) made from a chain extender (c), and has low compressibility and flexibility. In order to establish a high level of properties and wet film formability, the existence ratio of the amorphous phase of the urethane resin (X) by pulse NMR measurement is in the range of 20 to 50%, and the presence of a crystalline phase. It is essential that the ratio is in the range of 20-50%.

In general, the urethane resin (X) is composed of a soft segment composed of a polyol (a) and a hard segment composed of a urethane group or a urea group derived from a polyisocyanate (b) and a chain extender (c). It has been known. Here, the "amorphous phase" obtained by the pulse NMR measurement method indicates the soft segment, and the "crystalline phase" indicates the hard segment. Therefore, by setting the balance between the soft segment and the hard segment within the above range, low compressibility, flexibility, and wet film formability can be established at a high level. A method for measuring the pulse NMR will be described later in Examples.

In the pulse NMR measurement method, there exists a region called "intermediate phase" in addition to the "amorphous phase" and "crystalline phase". This is a region in which soft segments and hard segments coexist, and by controlling the structure in which the soft segments and hard segments are more phase-separated, the existence ratio of the intermediate phase can be reduced.

In the present invention, the existence ratio of the "amorphous phase" and the "crystalline phase" is positioned as a relatively high ratio, and in order to control the numerical range satisfying this at the same time, the existence of the "intermediate phase" How to reduce the ratio is important. As a technical idea that can set the abundance ratio of the "amorphous phase" and the "crystalline phase" within the range, for example, by using a polyol (a) having a relatively high molecular weight as a raw material, the abundance ratio of the soft segment using a relatively short chain length polyisocyanate (b) and a chain extender (c); devising the order in which the raw materials are reacted to make it easier to form a phase separation structure.

The existence ratio of the amorphous phase of the urethane resin (X) according to the pulse NMR measurement method is preferably in the range of 25 to 40% from the viewpoint of obtaining even better low compressibility and flexibility. , the existence ratio of the crystal phase is preferably in the range of 25 to 40%.

Examples of the polyol (a) that can be used include polyester polyol, polyether polyol, polycarbonate polyol, polyacrylic polyol, polybutadiene polyol, hydrogenated polybutadiene polyol, and dimer diol. These polyols may be used alone or in combination of two or more. Among these, it is preferable to use one or more selected from the group consisting of polyester polyols, polyether polyols, and polycarbonate polyols from the viewpoint of obtaining even more excellent wet film-forming properties. , polypropylene glycol and/or polytetramethylene glycol are preferred.

The number average molecular weight of the polyol (a) is preferably in the range of 500 to 100,000, more preferably in the range of 700 to 10,000, even more preferably in the range of 800 to 5,000. The number average molecular weight of the polyol (a) is the value measured by gel permeation chromatography (GPC).

The proportion of the polyol (a) used in the raw material constituting the urethane resin (X) is preferably in the range of 35 to 65% by mass, more preferably in the range of 40 to 60% by mass.

Examples of the polyisocyanate (b) include, for example, aliphatic polyisocyanates such as hexamethylene diisocyanate and lysine diisocyanate; Aromatic polyisocyanates such as phenylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, polymethylene polyphenyl polyisocyanate, and carbodiimidated diphenylmethane polyisocyanate can be used. These polyisocyanates may be used alone or in combination of two or more. Among these, it is preferable to use an aromatic polyisocyanate, and more preferable is diphenylmethane diisocyanate, from the viewpoint of obtaining even more excellent wet film-forming properties.

The ratio of the polyisocyanate (b) in the raw materials constituting the urethane resin (X) is 30, because it provides even better low compressibility, flexibility, and wet film-forming properties. A range of up to 45% by mass is preferred, and a range of 35 to 40% by mass is more preferred.

The chain extender (c) has a molecular weight of less than 500 (preferably in the range of 50 to 450). 5-dimethylpiperazine, isophoronediamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'- Chain extenders having amino groups such as dicyclohexylmethanediamine and hydrazine; 2,4-dimethyl-1,5-pentanediol, 2,3-dimethyl-1,5-pentanediol, 2-ethyl-1,5-pentane Diol, 2-methyl-1,6-hexanediol, 3-methyl-1,6-hexanediol, 1,7-nonanediol, 2-ethyl-1,6-hexanediol, 2-methyl-1,7- nonanediol, 3-methyl-1,7-nonanediol, 4-methyl-1,7-nonanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 3-methyl-1,8-octanediol, 4-methyl-1,8-octanediol, 1,10-decanediol, 2-methyl-1,10-decanediol , 3-methyl-1,10-decanediol, 4-methyl-1,10-decanediol, 1,11-undecanediol, trimethylolpropane, and other chain extenders having hydroxyl groups can be used. These chain extenders may be used alone or in combination of two or more. The molecular weight of the chain extender (c) indicates the chemical formula weight calculated from the chemical formula.

The proportion of the chain extender (c) in the raw material constituting the urethane resin (X) is preferably in the range of 5 to 20% by mass, more preferably in the range of 5 to 15% by mass.

Examples of the method for producing the urethane resin (X) include a method for producing by charging the polyol (a), the polyisocyanate (b), and the chain extender (c) and reacting them. These reactions are carried out, for example, at a temperature of 50 to 100° C. for 3 to 10 hours. Moreover, you may perform the said reaction in the organic solvent (Y) mentioned later.

The weight-average molecular weight of the urethane resin (X) is preferably in the range of 120,000 to 300,000, and from 140,000 to 140,000, from the viewpoint of obtaining even better low compressibility and wet film-forming properties. A range of 250,000 is more preferred. The weight average molecular weight of the urethane resin (X) is the value measured by gel permeation chromatography (GPC).

The content of the urethane resin (X) in the urethane resin composition is in the range of 5 to 80% by mass.

Examples of the organic solvent (Y) include ketones such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, methyl ethyl ketone, methyl-n-propyl ketone, acetone, and methyl isobutyl ketone. Solvent; ester solvents such as methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, isopropyl acetate, isobutyl acetate, isobutyl acetate, and sec-butyl acetate; alcohol solvents such as methanol, ethanol, isopropyl alcohol, butanol, etc. can be done. These organic solvents may be used alone or in combination of two or more.

The urethane resin composition of the present invention contains the urethane resin (X) as an essential component, but may contain other additives as necessary.

Examples of other additives include pigments, flame retardants, plasticizers, softeners, stabilizers, waxes, antifoaming agents, dispersants, penetrants, surfactants, fillers, antifungal agents, antibacterial agents, and ultraviolet rays. Absorbents, antioxidants, weather stabilizers, fluorescent whitening agents, anti-aging agents, thickeners and the like can be used. These additives may be used alone or in combination of two or more.

The 100% modulus of the film formed from the urethane resin composition obtained in a tensile test at a crosshead speed of 300 mm/min is in the range of 7 to 20 MPa in terms of obtaining even better flexibility. and more preferably in the range of 9 to 16 MPa. Incidentally, the method for measuring the 100% modulus of the film indicates a value measured by a method conforming to JISK:1995, and will be specifically described in Examples described later.

Next, a method for producing a porous body from the urethane resin composition by a wet film-forming method will be described.

The wet film-forming method involves coating or impregnating the surface of a substrate with the urethane resin composition, and then bringing the coated or impregnated surface into contact with water, steam, or the like to solidify the urethane resin (X). This is a method for producing a strained porous body.

As the base material to which the urethane resin composition is applied, for example, a base material made of a nonwoven fabric, a woven fabric, or a knitted fabric; a resin film or the like can be used. Chemical fibers such as polyester fiber, nylon fiber, acrylic fiber, polyurethane fiber, acetate fiber, rayon fiber, and polylactic acid fiber; cotton, hemp, silk, wool, and blended fibers thereof. etc. can be used.

If necessary, the surface of the base material may be subjected to antistatic treatment, release treatment, water repellent treatment, water absorption treatment, antibacterial deodorant treatment, antibacterial treatment, ultraviolet shielding treatment, and the like.

Examples of the method of applying or impregnating the urethane resin composition onto the substrate surface include gravure coater method, knife coater method, pipe coater method, and comma coater method. At that time, the amount of the organic solvent (Y) used may be adjusted as necessary in order to adjust the viscosity of the urethane resin composition and improve the coating workability.

The dry film thickness of the urethane resin composition applied or impregnated by the above method is, for example, in the range of 0.5 to 5 mm, preferably in the range of 0.5 to 3 mm.

As a method of bringing water or steam into contact with the coated surface formed by coating or impregnating the urethane resin composition, for example, a substrate provided with a coating layer or an impregnated layer made of the urethane resin composition is immersed in a water bath. a method of spraying water onto the coating surface using a spray or the like. The immersion is performed, for example, in a water bath at 5 to 60° C. for 2 to 20 minutes.

The surface of the porous body is preferably washed with room temperature water or warm water to extract and remove the organic solvent (Y), and then dried. The washing is preferably carried out with water of 5 to 60° C. for 20 to 120 minutes, and the water used for washing is preferably replaced once or more, or is preferably replaced continuously with running water. The drying is preferably carried out for 10 to 60 minutes using a dryer or the like adjusted to 80 to 120°C.

The porous body has a spindle-shaped or teardrop-shaped porous structure elongated in the thickness direction of the surface. As for the size of the pores, it is preferable that the diameter of the portion having the largest width in the surface direction is in the range of 1 to 70 μm. The thickness of the porous body is preferably from 0.4 to 1.2 mm for use in applications such as polishing pads, and more preferably from 0.4 to 1 mm.

As described above, the urethane resin composition of the present invention is excellent in low compressibility, flexibility, and wet film-forming properties.

Therefore, the urethane resin composition of the present invention can be suitably used as a polishing pad for finish polishing having a porous body obtained by a wet film-forming method.

The present invention will be described in more detail below using examples.

[Example 1]
A polyester polyol (reactant of ethylene glycol and adipic acid, number average molecular weight: 2,000, hereinafter abbreviated as "PEs (1)") was placed in a four-necked flask equipped with a stirrer, thermometer, and nitrogen gas inlet tube. ) 100 parts by mass, 1,4-butanediol (hereinafter abbreviated as “BG”) 20 parts by mass, N,N-dimethylformamide (hereinafter abbreviated as “DMF”) 564 parts by mass, and 4,4 Add 68 parts by mass of '-diphenylmethane diisocyanate (hereinafter abbreviated as "MDI"), react with stirring at 60°C for 6 hours, then add 1 part by mass of isopropyl alcohol, and further stir at 60°C for 1 hour. to obtain a urethane resin composition. The weight average molecular weight of the urethane resin was 188,100.

[Examples 2 to 5, Comparative Examples 1 to 3]
As shown in Tables 1 and 2, a urethane resin composition was obtained in the same manner as in Example 1, except that the types and amounts of materials were changed.

[Method for measuring number average molecular weight]
The number average molecular weight of polyols and the weight average molecular weight of urethane resins used in Examples and Comparative Examples are values measured under the following conditions by gel permeation chromatography (GPC).

Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series and used.
"TSKgel G5000" (7.8mm ID x 30cm) x 1 "TSKgel G4000" (7.8mm ID x 30cm) x 1 "TSKgel G3000" (7.8mm ID x 30cm) x 1 Book "TSKgel G2000" (7.8 mm I.D. x 30 cm) x 1 Detector: RI (differential refractometer)
Column temperature: 40°C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL/min Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass)
Standard sample: A calibration curve was created using the following standard polystyrene.

(standard polystyrene)
"TSKgel standard polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-550" manufactured by Tosoh Corporation

[Method for measuring 100% modulus]
A liquid mixture obtained by blending 100 parts by mass of the urethane resin composition obtained in Examples and Comparative Examples with 40 parts by mass of DMF was dried on a flat release paper ("EK-100D" manufactured by Lintec Co., Ltd.). It was applied to a thickness of 30 μm, dried at 90° C. for 2 minutes, and further dried at 120° C. for 2 minutes to prepare a film. Next, the resulting film was cut into strips with a width of 5 mm and a length of 70 mm. 100% modulus (MPa) was measured.

[Measurement method of pulse NMR]
For the film obtained in the above [100% modulus measurement method], the existence ratio (%) of the amorphous phase, the crystalline phase, and the intermediate phase was measured by pulse NMR (nuclear magnetic resonance) measurement under the following conditions. It was measured.

Measurement method: Solid Echo method by pulse NMR measurement Measurement equipment: "JNM-MU25" manufactured by JEOL Ltd.
Measurement conditions: 1H90 Pulse: 2.9 μS
Repeat time: 3s
Accumulated times: 32 times
Measurement temperature: 27°C

[Method for evaluating wet film formability]
100 parts by mass of the resulting urethane resin composition was coated on a polyethylene terephthalate (PET) film to a thickness of 1 mm and then immersed in water at 25° C. for 10 minutes to solidify. Thereafter, the film was washed in hot water at 50°C for 60 minutes and left in a dryer at 100°C for 30 minutes to obtain a processed film. The cross-sectional state of the obtained processed film was observed with a scanning electron microscope "JSM-IT500" manufactured by JEOL Ltd. (magnification: 100 times) to confirm the cell shape (fineness, uniformity), and the maximum width was If cells with a size of 70 μm or less accounted for 60% of the total, they were evaluated as “◯”, and otherwise as “X”.

[Evaluation method of compression rate]
The processed film obtained in the above [Method for evaluating wet film-forming properties] was evaluated for compressibility in accordance with JISL-1021-6. Specifically, the “thickness under standard pressure: t0” after applying an initial load of 2 kPa for 30 seconds was measured, and then the “thickness under constant pressure” after applying a final load of 98 kPa for 30 seconds. t1” was measured and applied to the following formula to calculate the compression rate.
Compression rate (%) = 100 x (t0-t1)/t0
If the obtained compression rate was 20% or less, it was evaluated as "good", and otherwise as "poor".

[Evaluation method for flexibility]
For the processed film obtained in the above [100% modulus measurement method], the storage elastic modulus (E') at 23 ° C. was measured by dynamic viscoelastic analysis under the following conditions in accordance with JISK7244-1999. ' was 200 MPa or less, it was evaluated as "◯", and otherwise, it was evaluated as "x".

Measuring device: viscoelastic spectrometer ("DMS6100" manufactured by SII Nanotechnology Co., Ltd.)
Temperature range: -100 to 250°C
Heating rate: 5°C/min Frequency 1Hz, tensile mode

Abbreviations in Tables 1 and 2 are explained.
"PEs (2)"; reactant of 1,4-butanediol and adipic acid, number average molecular weight; 2,000
"PEs (3)"; reaction product of ethylene glycol, 1,4-butanediol and adipic acid, number average molecular weight; 2,000
"PEs (4)"; reactant of 1,6-hexanediol and adipic acid, number average molecular weight; 2,000
"PEs (5)"; reaction product of 1,4-butanediol and adipic acid, number average molecular weight; 1,000
"PTMG"; polytetramethylene glycol, number average molecular weight; 2,000
"EG"; ethylene glycol The amount used in the table indicates parts by mass.
The usage ratio (% by mass) of the polyisocyanate (b) in the constituent raw materials indicates a value rounded to the first decimal place.

It was found that the urethane resin composition of the present invention is excellent in oleic acid resistance, low compressibility, flexibility, and wet film-forming properties.

On the other hand, Comparative Example 1 is an embodiment in which the abundance ratio of the amorphous phase is below the range defined by the present invention and the abundance ratio of the crystalline phase exceeds the range defined by the present invention, but the flexibility is poor. rice field.

Comparative Example 2 is an embodiment in which the existence ratio of the amorphous phase is below the range specified in the present invention, but the low compressibility property was poor.

Comparative Example 3 is an embodiment in which the abundance ratio of the amorphous phase exceeds the range specified in the present invention and the abundance ratio of the crystalline phase falls below the range specified in the present invention, but the low compressibility and the wet process The film formability was poor.

Claims (3)

A polishing pad having a porous body made of a urethane resin composition containing a urethane resin (X) made from a polyol (a), a polyisocyanate (b), and a chain extender (c),
The polyol (a) contains a polyester polyol,
The polyester polyol is a reaction product of ethylene glycol and adipic acid, a reaction product of 1,4 butanediol and adipic acid, a reaction product of ethylene glycol, 1,4 butanediol and adipic acid, and 1,6 hexanediol. is one or more selected from the group consisting of a reaction product of and adipic acid,
The number average molecular weight of the polyol (a) is in the range of 700 to 5000,
The polyisocyanate (b) is diphenylmethane diisocyanate,
the chain extender (c) is ethylene glycol or 1,4-butanediol,
The use ratio of the polyol (a) is in the range of 40 to 65% by mass in the raw material of the urethane resin (X),
The use ratio of the polyisocyanate (b) is in the range of 30 to 40% by mass in the raw material of the urethane resin (X),
The proportion of the chain extender (c) used is in the range of 5 to 20% by mass in the raw material of the urethane resin (X),
A polishing pad characterized by having an amorphous phase abundance ratio of 34 to 50% and a crystalline phase abundance ratio of 20 to 32% measured by a pulse NMR measurement method. . 2. The polishing pad according to claim 1, wherein the urethane resin (X) has a weight average molecular weight in the range of 120,000 to 300,000. 3. The polishing pad according to claim 1 , which is used for finish polishing.