Polyurethane resin composition for support pad and polyurethane support pad using the same

Abstract

The present invention relates to a polyurethane resin composition for a support pad including a polyurethane resin, a DMF solvent, an anionic surfactant, and polyethylene glycol (PEG), and a polyurethane support pad including the polyurethane resin composition for a support pad. According to the present invention, long and large pores may be uniformly formed therein, and thus a support pad having an excellent compression rate and compression recovery rate may be provided.

Claims

1. A polyurethane resin composition for a support pad comprising: 3 to 50 wt % of a polyurethane resin based on total weight of the polyurethane resin composition; 40 to 90 wt % of a dimethylformamide (DMF) solvent based on total weight of the polyurethane resin composition; 0.05 to 5 wt % of an anionic surfactant based on total weight of the polyurethane resin composition; and 0.1 to 5 wt % of polyethylene glycol (PEG) based the total weight of the polyurethane resin composition, and wherein the anionic surfactant includes at least one selected from the group consisting of dodecylbenzenesulfonic acid, sodium dodecylbenzenesulfonate, potassium dodecylbenzenesulfonate, and ammonium dodecylbenzenesulfonate.

2. The polyurethane resin composition for a support pad according to claim 1, wherein the polyurethane resin has weight average molecular weight of 30,000 to 1,000,000.

3. The polyurethane resin composition for a support pad according to claim 1, wherein the polyurethane resin has a viscosity of 30,000 to 1,000,000 cps in a 30 wt. % polyurethane resin-DMF solution state, based on total weight of the polyurethane resin-DMF solution, at room temperature.

4. The polyurethane resin composition for a support pad according to claim 1, wherein the anionic surfactant further includes at least one selected from the group consisting of succinic acid, sodium succinate, potassium succinate, ammonium succinate, dodecyl sulfate, sodium dodecyl sulfate, potassium dodecyl sulfate, and ammonium dodecyl sulfate.

5. The polyurethane resin composition for a support pad according to claim 1, wherein the polyethylene glycol has weight average molecular weight of 100 to 10,000.

6. The polyurethane resin composition for a support pad according to claim 1, further comprising a nonionic surfactant.

7. The polyurethane resin composition for a support pad according to claim 1, further comprising at least one additive selected from the group consisting of a coloring agent, a water repellent, a filler, a pore size control agent, and a pigment.

8. A polyurethane support pad comprising a solidified product of the polyurethane resin composition of claim 1.

9. The polyurethane support pad according to claim 8, wherein the polyurethane support pad has density of 0.10 to 0.35 g/cm.sup.2.

10. The polyurethane support pad of claim 8, wherein the polyurethane support pad has a compression rate of 30% or more and a compression recovery rate of 95% or more according to JIS L1021-16.

11. The polyurethane support pad according to claim 8, comprising pores with an aspect ratio (ratio of length to width) of 3 to 10.

12. A polyurethane resin composition for a support pad comprising: a polyurethane resin; a dimethylformamide (DMF) solvent; an anionic surfactant; and polyethylene glycol (PEG), wherein the anionic surfactant includes at least one selected from the group consisting of dodecylbenzenesulfonic acid, sodium dodecylbenzenesulfonate, potassium dodecylbenzenesulfonate, and ammonium dodecylbenzenesulfonate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a SEM photograph of a cross-section of a polyurethane pad prepared in Example 1.

(2) FIG. 2 shows a SEM photograph of a cross-section of a polyurethane pad prepared in Example 2.

(3) FIG. 3 shows a SEM photograph of a cross-section of a polyurethane pad prepared in Example 3.

(4) FIG. 4 shows a SEM photograph of a cross-section of a polyurethane to pad prepared in Example 4.

(5) FIG. 5 shows a SEM photograph of a cross-section of a polyurethane pad prepared in Comparative Example 1.

(6) FIG. 6 shows a SEM photograph of a cross-section of a polyurethane pad prepared in Comparative Example 2.

DETAILS FOR PRACTICING THE INVENTION

(7) Hereinafter, the present invention will be explained in detail with reference to the following examples. However, these examples are only to illustrate the invention, and the scope of the invention in not limited thereto.

Example and Comparative Example: Preparation of Polyurethane Resin Composition and Polyurethane Support Pad

Example 1

(8) Into a 1 L polypropylene bottle, 100 g of polyurethane resin (a 30 wt % DMF solution), 65 g of N,N′-dimethylformamide, 4 g of a succinic acid derivative (SD-11, Pentachem), 0.5 g of para-dodecylbenzenesulfonic acid (DBSA), 2 g of a nonionic surfactant (SD-7, Pentachem), 7 g of a coloring agent (PS-7351 N, carbon black containing resin, Pentachem), 2 g of a filler (FAT-17, Pentachem), and 2 g of a water repellent (fluorinated resin, FPU-60, Pentachem) were introduced, and the mixture was agitated at a high speed for 10 minutes with a paint shaker, and then centrifuged at 3000 rpm for 10 minutes to obtain a polyurethane resin composition.

(9) The resultant slurry was coated on a PET film to a thickness of 2.00 mm, and then a wet solidification process was progressed in a solidification bath of a 4 Brix % concentration. The obtained solidified product was washed, dehydrated, and dried to prepare a polyurethane support pad.

Examples 2 to 4

(10) Polyurethane resin compositions and polyurethane support pads were prepared by the same method as Example 1, except changing the compositions as described in the following Table 1.

Comparative Examples 1 and 2

(11) Polyurethane resin compositions and polyurethane support pads were prepared by the same method as Example 1, except changing the compositions as described in the following Table 1.

(12) TABLE-US-00001 TABLE 1 Compositions of the resin compositions of examples and comparative examples Polyurethane Nonionic coloring water resin Surfactant SD-11 DBS A agent DMF repellent filler PEG (g) (g) (g) (g) (g) (g) (g) (g) (g) Example 1 L07 (100) SD-7 (2) 4 0.5 7 65 2 2 Mw. 200 (2) Example 2 L07 (50) SD-7 (2) 4 0.5 7 60 2 2 Mw. 600 L08 (50) (2) Example 3 L07 (50) SD-7 (2.5) 4 0.5 7 55 2 2 Mw. 600 L08 (50) (2) Example 4 L07 (100) 0 6 5 65 2 2 0 Mw. 2000  (2) Comparative L08 (100) SD-7 (2) 4 0 6 45 2 2 — Example 1 Comparative L07 (100) SD-7 (2) 4 0.5 7 60 2 2 — Example 2 * L07: 30 wt % polyurethane DMF solution (LG Chemical, 500K cps) * L08: 30 wt % polyurethane DMF solution (LG Chemical, 500K cps) * SD-11: Sodium dioctyl sulfosuccinate * SD-7: branched polyether type polyol

Experimental Example: Measurement of Compression Rate and Compression Recovery Rate of Polyurethane Support Pad

(13) The densities, compression rates, and compression recovery rates of the support pads obtained in the examples and comparative examples, and the size of the pores formed on the support pads, were measured.

(14) The results are described in the following Table 2.

Experimental Example 1: Measurement of Density of Support Pad

(15) The polyurethane pads obtained in the examples and comparative examples were prepared with a size of 30 mm*30 mm, the thicknesses were measured, the weights of the specimens were measured, and the densities is were calculated.

(16) The measurement of density was repeated 5 times, and the density of the support pad was calculated from the average value.

Experimental Example 2: Measurement of Compression Rate and Compression Recovery Rate of Support Pad

(17) The compression rate and compression recovery rate of the support pad were measured according to JIS L1021-16. 2.5 cm*3.0 cm (width*length) specimens of the polyurethane support pads of the examples and comparative examples were prepared. An initial load of 100 g/cm.sup.2 was applied to the specimen for 30 seconds, and then the initial thickness was measured with a dial gauge (T0), and after standing under a load of 1120 g/cm.sup.2 for 5 minutes, the thickness was measured under pressure (T1).

(18) Subsequently, all the loads were removed, and after standing for 5 minutes, the initial load of 100 g cm.sup.2 was applied again for 30 seconds, and then the thickness was measured (T0′).

(19) Each measured thickness was applied to the following equation to calculate the compression rate and the compression recovery rate.
Compression rate (%)=(T0−T1)*100/T0
Compression recovery rate (%)=(T0′−T1)*100/(T0−T1)  [Equation]

(20) Specific results of Experimental Examples 1 and 2 are described in the following Table 2.

(21) TABLE-US-00002 TABLE 2 Results of Experimental Examples 1 to 2 Compression Density Compression recovery (g/cm.sup.2) rate (%) rate (%) Example 1 0.25 33 97 Example 2 0.25 38 98 Example 3 0.23 42 96 Example 4 0.23 45 96 Comparative 0.35 10 77 Example 1 Comparative 0.28 30 90 Example 2

(22) As shown in Table 2, it was confirmed that the support pads of the examples prepared using a composition including polyethylene glycol have low density, and yet exhibit a high compression rate and compression recovery rate, compared to the support pads of the comparative examples which do not include polyethylene glycol.

(23) Further, as shown in FIGS. 1 to 5, the support pads of the examples have long and large pores uniformly formed inside of the sheets, while the absorption pads of the comparative examples have comparatively short and small pores and the distribution of the pores is non-uniform.

(24) Accordingly, the support pads of the examples may improve cushionability and adsorption to an object to be polished, and firmly fix an object to be polished on a pad during polishing of the object, thus preventing lowering of polishing quality.

Experimental Example 3: Measurement of the Size of Pores Formed on the Support Pad

(25) SEM photographs of the cross-sections of the polyurethane support pads of the examples and comparative examples were taken, and then the size of the pores distributed in polyurethane was measured.

(26) As the result, it was confirmed that pores with the longest diameter of 500 μm to 1 mm are included in the polyurethane support pads of the examples.

(27) Further, most of the pores distributed in the polyurethane support pads have an aspect ratio (ratio of length to width) of 3 to 10.

(28) To the contrary, it was confirmed that in the polyurethane support pads of the comparative examples, pores that have comparatively short longest diameter and low aspect ratio of length to width, and thus are close to a spherical shape, are included.

(29) That is, according to the examples, a polyurethane support pad having uniformly distributed long and large pores may be provided, and if the support pad is used, air that is trapped between the support pad and a film to be polished may be easily transferred to the inside of the support pad, and force applied in a polishing step may be uniformly distributed to the whole support pad and the whole object to be polished, thus minimizing poor polishing and achieving a high compression rate and compression recovery rate.