Sponge-like porous body, polishing pad, liquid-absorbing pad, cleaning sponge, cultivation sponge, and method for producing sponge-like porous body

Abstract

The invention relates to a spongy porous body, a polishing pad, a liquid absorbing pad, a cleaning sponge, a cultivation sponge and a manufacturing method of the spongy porous body. Provided is a spongy porous body which is elastic and flexible, and which has hydrophilic properties from the front surface portion to the inside. The spongy porous body has a substrate with pores, in which an inner wall of the pores has a hydrophilic film in a region of a depth of 0% to 20% or more of the thickness of the spongy porous body in a thickness direction from a front surface portion to a rear surface portion.

Description

Technical Field

[0001] The invention relates to a sponge-like porous body, a polishing pad, a liquid absorbing pad, a cleaning sponge, a cultivation sponge and a method for manufacturing the sponge-like porous body. Background Art

[0002] Sponge-like porous bodies are used in various situations. For example, the polishing pads used to polish silicon wafers or glass to a flat surface are mostly sponge-like porous bodies made of polyurethane. Sponge-like porous bodies called waste ink absorbers are used in inkjet printers to hold waste ink. In addition, various sponge-like porous bodies are commercially used for cleaning, such as washing dishes, washing cars, and washing the human body. In addition, sponge-like porous bodies are sometimes used to replace soil for hydroponic cultivation.

[0003] For these sponge-like porous bodies, hydrophilicity is usually important. For example, in polishing pads, the increased hydrophilicity improves the retention of the polishing liquid, so more abrasive particles will act on the front surface of the processed product, resulting in increased polishing performance. The improvement of polishing performance not only improves the productivity of the polishing process, but also has the effect of reducing the use of rare metals as raw materials for polishing materials. In waste ink absorbers, the increased hydrophilicity will increase the retention of ink and can prevent the contamination of the printer head due to the rebound or leakage of the absorbent pad. When cleaning sponges, the increased hydrophilicity also improves the foaming and cleaning effects and improves water absorption. The increased hydrophilicity of hydroponic sponges will increase the retention of water and fertilizers and can effectively supply them to plants.

[0004] A known method for improving the hydrophilicity of a sponge-like porous body involves mixing a hydrophilic material with the material of the sponge-like porous body to produce the porous body. For example, Japanese Patent Application Publication No. 2015-120220 discloses increasing the hydrophilicity by mixing a hydrophilic resin (epoxy resin) into a polyurethane polishing pad.

[0005] Another known method involves spraying a hydrophilic material onto the surface of a sponge-like porous body. For example, Yohei Kitai et al., "Improved Polishing Performance for Glass by a Novel Suede Pad Utilizing Epoxy Resin", Journal of the Society of Mechanical Engineers (Edition C), Vol. 79, No. 808 (2013-12), pp. 5019-5028, discloses improving the polishing properties of a polyurethane polishing pad by applying an epoxy resin (which is a hydrophilic resin) onto the surface of the polishing pad.

[0006] However, in the method disclosed in Japanese Patent Application Publication No. 2015-120220, the hydrophilic material is harder than the original sponge-like porous material, and the sponge-like porous body made by mixing the hydrophilic material loses elasticity and flexibility. The loss of elasticity and flexibility leads to a decrease in the shape following property, processability and durability of the sponge-like porous body.

[0007] Although the method disclosed in Yohei Kitai et al., "Improved Polishing Performance for Glass by a Novel Suede Pad Utilizing Epoxy Resin", Journal of the Society of Mechanical Engineers (Edition C), Vol. 79, No. 808 (2013-12), pp. 5019-5028, allows the original sponge-like porous material to maintain elasticity and flexibility, only the vicinity of the surface of the sponge-like porous body can be hydrophilized. In the case of a polishing pad, the surface of the polishing pad is scraped off according to the polishing time. Therefore, if only the vicinity of the surface of the polishing pad is hydrophilized, the hydrophilicity can only be maintained for a short period of time. In addition, other sponge-like porous bodies also have the problem that the hydrophilic effect is limited to the vicinity of the surface.

[0008] Therefore, an object to be achieved by the present invention is to provide a sponge-like porous body which is an elastic and flexible porous body, and a sponge-like porous body having hydrophilic properties from the front surface portion to the inside. Summary of the invention

[0009] In order to achieve the above-mentioned purpose, the present invention provides a sponge-like porous body, which has a porous substrate, wherein, in the area from 0% depth to more than 20% depth of the thickness of the sponge-like porous body in the thickness direction from the front surface portion to the rear surface portion, the inner wall of the hole has a hydrophilic film; and the substrate contains a foamed resin.

[0010] The present invention also provides a polishing pad, a liquid absorption pad, a cleaning sponge and a cultivation sponge, each of which comprises the sponge-like porous body.

[0011] The present invention also provides a method for manufacturing a sponge-like porous body, the method comprising: providing a substrate having pores; and forming a hydrophilic film on the inner wall of the pores by atomic layer deposition (ALD), wherein the substrate comprises at least one selected from polyurethane, polyether and polyethylene.

[0012] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1Ais a perspective view of a sponge-like porous body according to an embodiment of the present invention.

[0014] Figure 1B is along Figure 1A Schematic diagram of the cross section taken along line A-A'.

[0015] Figure 2A is a perspective view of a sponge-like porous body (closed-cell type) according to an embodiment of the present invention.

[0016] Figure 2B is along Figure 2A Schematic diagram of the cross section taken along line A-A'.

[0017] Figure 2C is a schematic diagram showing the making of longitudinal holes in a sponge-like porous body using a needle.

[0018] Figure 2D It is to make longitudinal holes in a sponge-like porous body with a needle and then Figure 2C Schematic diagram of the cross section taken along line A-A'.

[0019] Figure 3A is a schematic perspective view showing a CMP polishing step.

[0020] Figure 3B yes Figure 3A Side view of.

[0021] Figure 4 is a schematic perspective view of an inkjet printer.

[0022] Figure 5 This is a schematic diagram of an ALD film forming apparatus. DETAILED DESCRIPTION

[0023] The preferred embodiment of the present invention will now be described in detail according to the accompanying drawings. Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. However, the embodiment to be described below is only one embodiment of the present invention, and the present invention is not limited thereto. Common configurations will be described with reference to a plurality of accompanying drawings, and descriptions of configurations represented by the same reference numerals will be omitted where appropriate.

[0024] <First embodiment>

[0025] The first embodiment relates to a sponge-like porous body.

[0026] The sponge-like porous body of the present invention is a sponge-like porous body having a porous substrate, wherein

[0027] The inner wall of the pore has a hydrophilic film in a region from 0% depth to 20% or more depth of the thickness of the sponge-like porous body in the thickness direction from the front surface portion to the rear surface portion; and

[0028] The substrate comprises a foamed resin.

[0029] In this specification, a sponge-like porous body refers to a flexible and elastic porous body including many sponge-like pores, which will be described below.

[0030] Figure 1A A perspective view showing a sponge-like porous body according to a first embodiment is shown. Figure 1B Shown along Figure 1A Schematic diagram of a section taken along line A-A' of the sponge-like porous body 101. The sponge-like porous body 101 of the first embodiment has a substrate having many holes 102 therein. The inner wall of the hole has a hydrophilic membrane (not shown) in a region from 0% depth to 20% or more depth of the sponge-like porous body 101 in the thickness direction from the front surface portion 103 to the rear surface portion of the sponge-like porous body 101. The inner wall of the hole preferably has a hydrophilic membrane in a region from 0% depth to 50% or more depth of the thickness of the sponge-like porous body 101 in the thickness direction from the front surface portion 103 to the rear surface portion of the sponge-like porous body 101.

[0031] Here, if Figure 1B As shown, the thickness direction from the front surface portion to the rear surface portion of the sponge-like porous body is a direction perpendicular to the front surface portion and the rear surface portion of the sponge-like porous body, and 0% in the thickness direction represents the front surface portion of the sponge-like porous body, and 100% represents the rear surface portion of the sponge-like porous body. For example, 50% in the thickness direction therefore represents the center in the thickness direction. In the present invention, the front surface portion of the sponge-like porous body is, for example, Figure 1A and 1B The upper surface (top surface) of the sponge-like porous body in the embodiment of the present invention is the upper surface (top surface) of the sponge-like porous body, and the rear surface of the sponge-like porous body is Figure 1A and Figure 1B The bottom surface portion (bottom face) of the sponge-like porous body.

[0032] The expression "the inner wall of the pore has a hydrophilic film" means in this article that not all the inner walls of the pores need to have a hydrophilic film, but more than 50% of the pores can have a hydrophilic film. When a section is obtained in a plane parallel to the front surface portion 103, 50% of the pores means more than 50% of the number of pores present in the section. Therefore, the expression "the inner wall of the pore has a hydrophilic film in the region from 0% depth to more than 20% depth of the thickness of the sponge-like porous body in the thickness direction from the front surface portion to the rear surface portion" can be interpreted as follows: more than 50% of the pores in the front surface portion 103 of the sponge-like porous body also have a hydrophilic film; and when a section is obtained in a plane parallel to the front surface portion 103 at a point 20% of the depth from the front surface portion 103 of the sponge-like porous body in the thickness direction, more than 50% of the pores appearing in the section have a hydrophilic film.

[0033] The sponge-like porous body is generally elastic and flexible. In the present invention, the expression "the sponge-like porous body is elastic and flexible" indicates that the hardness of the sponge-like porous body is small. As an indicator showing that the hardness of the sponge-like porous body is small, the hardness of the sponge-like porous body of the present invention is preferably 90 points or less, more preferably 80 points or less, and particularly preferably 75 points or less, measured by a type A durometer (Japanese Industrial Standard, JIS K 7215). The thickness of the sponge-like porous body of the present invention is preferably 0.1 mm or more. In particular, in order to be used as a polishing pad, the thickness of the sponge-like porous body is also preferably 0.5 mm or more, because a polishing pad thinner than 0.5 mm has problems such as insufficient strength, which makes the sponge-like porous body easy to tear when fixed to a polishing tool.

[0034] Examples of materials of the spongy porous body substrate include polyurethane, polyether, polyethylene and resin materials containing these polymers. In the spongy porous body of the present invention, the substrate preferably includes at least one selected from polyurethane, polyether and polyethylene, and more preferably includes a polyurethane with excellent flexibility. In the spongy porous body of the present invention, the substrate preferably includes a foamed resin. In this configuration, the spongy porous body may have elasticity and flexibility. In the present invention, the elasticity and flexibility of the spongy porous body are embodied by the hardness of the spongy porous body, and the expression "spongy porous body has elasticity and flexibility" means that, for example, the hardness of the spongy porous body is preferably less than 90 points, more preferably less than 80 points, and particularly preferably less than 75 points, measured by a type A durometer (ASKER rubber hardness tester type A, manufactured by KOBUNSHI KEIKI CO., LTD.).

[0035] In the first embodiment, the hydrophilicity is improved until the inside of the sponge-like porous body, but in order to obtain equivalent performance near the surface and inside, the film thickness value of the hydrophilic film on the inner wall of the pores in each region is preferably the same near the surface and inside. The average thickness of the hydrophilic film on the inner wall of the pores in the region with a depth of more than 0% and less than 20% of the thickness of the sponge-like porous body in the thickness direction from the front surface portion to the rear surface portion of the sponge-like porous body is represented by D1. The average thickness of the hydrophilic film on the inner wall of the pores in the region (central portion) with a depth of more than 40% and less than 60% of the thickness of the sponge-like porous body in the thickness direction from the front surface portion to the rear surface portion of the sponge-like porous body is represented by D2. In this case, D1 and D2 in the sponge-like porous body of the present invention are preferably 10 nm or more and 10 μm or less, and satisfy the inequality 0.7×D2≤D1≤1.3×D2, and both D1 and D2 are more preferably 10 nm or more and 120 nm or less, and satisfy the inequality 0.9×D2≤D1≤1.1×D2. Here, the reason why the values ​​of 10 nm or more and 10 μm or less are preferred as D1 and D2 is that if the film thickness value of the hydrophilic film is less than 10 nm, the hydrophilic property is poor, and if the film thickness value is greater than 10 μm, cracking or peeling occurs due to film stress, thereby impairing the function of the film. The reason why the inequality 0.7×D2≤D1≤1.3×D2 is preferred is that if the film thickness values ​​are close to each other, equivalent hydrophilic properties can be obtained; and although the opening of the pore is narrowed by the film, the closer the film thickness value, the more equivalent the size of the opening, so that there is no difference in the performance of the sponge-like porous body.

[0036] In the sponge-like porous body of the present invention, the hydrophilic film on the inner wall of the pores of the sponge-like porous body is preferably an oxide film, more preferably an inorganic oxide film. Generally, compared with, for example, an organic film, an oxide film exhibits high hydrophilicity and has the advantage of high adhesion to the substrate. Examples of oxide films include SiO2, Al2O3, TiO2, Ta2O5, HfO2 and RuO2. In the sponge-like porous body of the present invention, the material of the oxide film preferably comprises a mixture of one or more selected from SiO2, Al2O3, TiO2, Ta2O5, HfO2 and RuO2, and from the perspective of hydrophilicity and ease of film formation, it is particularly preferred to contain SiO2.

[0037] In addition, when the oxide film contains CH groups, the adhesion of the hydrophilic film is improved by combining with the CH groups contained in the sponge-like porous body. Therefore, the oxide film may contain C (carbon). In the sponge-like porous body of the present invention, the C content in the oxide film is preferably greater than 0.5at% and less than 25at% (greater than 0.5 atomic% and less than 25 atomic%), so that the sponge-like porous body can have sufficient hydrophilicity. Note that when the C content is less than 0.5at%, it is difficult for the analytical instrument to detect, and when the C content is greater than 25at%, the hydrophilicity is insufficient. The C content in the oxide film can be analyzed by XPS (X-ray photoelectron spectroscopy).

[0038] <Second Implementation Method>

[0039] The second embodiment relates to a method for producing a sponge-like porous body.

[0040] The method for manufacturing a sponge-like porous body of the present invention comprises: providing a substrate having pores; and forming a hydrophilic film on the inner wall of the pores by ALD (atomic layer deposition), wherein the substrate comprises a foamed resin; and the substrate comprises at least one selected from polyurethane, polyether and polyethylene.

[0041] Hereinafter, each step will be described. Since the substrate itself is as described above, its description is omitted.

[0042] (Provide steps)

[0043] The method for manufacturing a sponge-like porous body of the present invention includes providing a substrate having holes. The method for manufacturing the substrate is not particularly limited, as long as the desired flexibility and elasticity (hardness) can be obtained, and the following known methods can be used: for example, a curing agent and hollow particles (such as resin balloons) are mixed in polyurethane and cured, and then heat-treated to expand the hollow particles, thereby manufacturing a sponge-like porous body. The chemical foaming agent dispersed in the polyurethane is thermally decomposed, and bubbles are generated by the generated gas, thereby manufacturing a sponge-like porous body. In addition, for example, a curing agent is added after manufacturing a W / O type emulsion of polyurethane and water, and then water and air are replaced after curing to manufacture a sponge-like porous body.

[0044] For example, a curing agent is added by kneading salt into polyurethane. After molding, the salt is dissolved with water or other media to produce a sponge-like porous body. Another example is that a curing agent is added after a chemical foaming agent is dispersed in polyurethane, heated to decompose the chemical foaming agent, and then bubbles are generated by the generated gas to produce a sponge-like porous body. In addition, for example, a curing agent is added after the gas is dissolved in the polyurethane by applying pressure, and then the pressure of the gas generated by decompression is foamed to produce a sponge-like porous body. Although polyurethane is mentioned as an example, the manufacturing method can also be applied to polyether, polyethylene and other resins. The substrate preferably includes at least one selected from polyurethane, polyether and polyethylene, more preferably polyurethane. The substrate preferably includes a foamed resin. Therefore, a flexible and elastic sponge-like porous body can be produced.

[0045] In the providing step of the present invention, the substrate may be provided by the above-mentioned production method, or the substrate such as a manufactured product may be provided.

[0046] (Film Forming Step)

[0047] The method for manufacturing a sponge-like porous body of the present invention includes forming a hydrophilic film on the inner wall of the pore by ALD (atomic layer deposition). The method for manufacturing a sponge-like porous body of the present invention includes a film forming step after the providing step. An example of a method for applying a hydrophilic film with uniform film thickness from the front surface portion to the inside of the sponge-like porous body includes ALD (atomic layer deposition) described later. ALD supplies the film material in the form of a gas, thereby forming a film within the reach of the gaseous material. In addition, ALD is a method of stacking atomic layers layer by layer so that the film has a uniform thickness regardless of the shape and position of the substrate. Thus, a sponge-like porous body having hydrophilic properties from the front surface portion to the inside can be manufactured.

[0048] In the second embodiment, a method of forming a hydrophilic film on the inner wall of the pores of a sponge-like porous body will be described. ALD (Atomic Layer Deposition) can be used to form the hydrophilic film. Figure 5 The ALD film forming apparatus 501 is equipped with an exhaust unit 503 for evacuating the inside of a chamber, a heater 504 for heating a substrate, and a plurality of gas supply units 507 for attaching a film to a substrate 506 on a substrate holder 505 .

[0049] The film forming process is as follows:

[0050] (Step 1) Installing the substrate 506 and evacuating the substrate;

[0051] (Step 2) Heating the substrate 506 to a predetermined temperature by the heater 504;

[0052] (Step 3) supplying a precursor through a gas supply unit 507;

[0053] (Step 4) Introducing a rare gas such as Ar through the gas supply unit 507 for purging (eliminating excess precursor);

[0054] (Step 5) Supplying reactive gases such as H2O and O2 through the gas supply unit 507 to oxidize the film;

[0055] (Step 6) Introducing a rare gas such as Ar through the gas supply unit 507 for purging;

[0056] (Process 7) When steps 3 to 6 are regarded as one cycle, a film having a thickness of one atomic layer (thickness of about 0.1 to 1.0 nm) is formed in one cycle, thereby repeating the cycle until a desired film thickness is obtained; and

[0057] (Step 8) The vacuum chamber 502 is opened to the atmosphere to remove the substrate 506.

[0058] (Through-hole forming step)

[0059] In the method for manufacturing a sponge-like porous body of the present invention, the above-mentioned providing step preferably includes forming through holes in the substrate, so that even if the sponge-like porous body has discontinuous pores (in the case where the pores are not connected to each other), a sponge-like porous body having hydrophilic properties from the front surface portion to the inside can be manufactured.

[0060] Sponge-like porous bodies can be roughly divided into open-cell type and closed-cell type. In the open-cell type, the pores inside the sponge-like porous body are connected to the adjacent pores, while in the closed-cell type, some pores are not connected to the adjacent pores and are spatially isolated. In the film formation on these sponge-like porous bodies by ALD, it is considered that the gaseous material diffuses to almost all the pores in the open-cell type but does not reach some pores in the closed-cell type. Therefore, when the second embodiment is applied to a closed-cell sponge-like porous body, it is preferably performed as follows Figure 2C and 2D Steps shown.

[0061] Figure 2A is a perspective view of a sponge-like porous body (closed-cell type) according to an embodiment of the present invention, and Figure 2B is along Figure 2A Schematic diagram of the cross section taken along line A-A'. Figure 2C is a schematic diagram showing the use of a needle to make longitudinal holes in a sponge-like porous body, and Figure 2D A needle is used to make longitudinal holes in a sponge-like porous body and then Figure 2C Schematic diagram of the cross section taken along the line A-A'. Figure 2A and 2B The closed-cell sponge-like porous body 201 shown in FIG. 2 is provided with longitudinal holes (through holes) 204, such as Figure 2C and 2DAs shown. Thereafter, when a hydrophilic film is formed by a method such as ALD, the hydrophilic film can be attached to the pores 202 inside the sponge-like porous body. The longitudinal pores (through holes) 204 are not necessarily holes that pass through from the front surface to the rear surface of the sponge-like porous body, but may be holes that connect the pores 202 to each other so that the inside of the sponge-like porous body can have a hydrophilic film.

[0062] <Application Examples>

[0063] Hereinafter, application examples using the sponge-like porous body shown in the first embodiment will be described in detail.

[0064] (Polishing pad)

[0065] The polishing pad of the present invention preferably has the sponge-like porous body of the present invention. Figure 3A and 3B The case where the sponge-like porous body of the application example is used as a polishing pad is shown. Figure 3A is a schematic perspective view showing a CMP polishing device 301, Figure 3B yes Figure 3A Side view of a 3D printed circuit board. CMP stands for chemical mechanical polishing, a polishing technique commonly used in semiconductor manufacturing. Figure 3A and 3B In the CMP, the polishing object (workpiece) is described as a silicon wafer, but is not limited thereto. In CMP, a silicon wafer 305 as a workpiece is brought into contact with a polishing pad 303 by applying a load 308 .

[0066] In the polishing pad of the present invention, the front surface portion is preferably used as a polishing surface, and the object to be polished is polished using a polishing liquid. Then, the stage 302 is rotated, and the polishing liquid 307 is dripped from the polishing liquid supply unit 306, and the silicon wafer 305 and the polishing pad 303 slide with each other to polish the silicon wafer 305 fixed to the workpiece holding member 304. As the polishing pad 303, the sponge-like porous body of this application example can be used alone or in a stacked body of multiple pads. The thickness of the polishing pad 303 is not limited, and is about 0.1 to 2.0 mm, more preferably about 0.4 to 0.8 mm. In addition, the polishing pad 303 is not limited to the sponge-like porous body of this application example, and an intermediate layer such as a substrate or a cushion layer can be bonded to the opposite side of the polishing surface of the sponge-like porous body.

[0067] In the sponge-like porous body of the present invention, in the "(Evaluation of Polishing Rate and Polishing Rate Stability)" section and Table 1 described later, the glass polishing rate before the accelerated durability test is preferably 0.70 μm / min or more. In the sponge-like porous body of the present invention, the glass polishing rate after the accelerated durability test is preferably 0.70 μm / min or more. In the sponge-like porous body of the present invention, the value obtained by dividing the glass polishing rate after the accelerated durability test by the glass polishing rate before the accelerated durability test is preferably 0.70 or more.

[0068] In the durability acceleration test in the section “(Evaluation of Polishing Pad Durability)” described later and in Table 1, the sponge-like porous body of the present invention preferably has a wear rate of 0.40 μm / min or less.

[0069] The polishing pad of the application example has a higher polishing effect than the polishing pad to which the sponge-like porous body of the present invention is not applied, and has the effect of maintaining the performance as a polishing pad even if the polishing pad is worn to a certain extent.

[0070] (Liquid Absorbent Pad)

[0071] Subsequently, a case where the sponge-like porous body of the application example is used as a liquid absorption pad (eg, ink absorption pad) will be described. The liquid absorption pad of the present invention preferably has the sponge-like porous body of the present invention. Figure 4 A schematic perspective view of a general inkjet printer is shown. When a printer cover 402 is opened, an inkjet head 403 to which ink tanks 404 of various colors are attached is held by a shaft 405. The inkjet printer 401 draws a desired image on a paper surface by ejecting ink onto a paper 406 while moving the inkjet head 403 along the shaft 405.

[0072] Inkjet printers usually require pre-ejection. If the printer is not used for a long time, the ink at the nozzle tip of the nozzle will inevitably dry and thicken, resulting in unstable ejection. In order to prevent this instability, a certain amount of ink is ejected to refresh the printer before starting to draw. In the pre-ejection, unnecessary ink is ejected to the ink absorbing pad. In this case, the ink absorbing pad is required to have a high ink retention, because any ink rebound or ink leakage from the ink absorbing pad will adversely affect subsequent drawing. The sponge-like porous body of the application example has high hydrophilicity and can therefore be used as an ink absorbing pad.

[0073] (Cleaning sponge)

[0074] In addition, the sponge-like porous body of this application example can be used as a cleaning sponge. The cleaning sponge of the present invention preferably has the sponge-like porous body of the present invention. In addition to sponges for washing dishes, car wash sponges for washing cars, etc., and body sponges for washing human bodies, the cleaning sponges used herein include water-absorbing sponges for wiping off moisture from tableware, cars or human bodies. These cleaning sponges have the effect of firmly retaining moisture and detergents (shampoo), and improve foam retention by increasing hydrophilic properties. In the case of water-absorbing sponges, water absorption performance is also enhanced.

[0075] (Cultivated sponge)

[0076] Finally, the sponge-like porous body of this application example can be used as a sponge for hydroponic cultivation. The cultivation sponge of the present invention preferably has the sponge-like porous body of the present invention. By enhancing the hydrophilicity of the sponge for hydroponic cultivation, water and nutrients can be effectively supplied to plants.

[0077] Example

[0078] The present invention is described in detail below with reference to Examples and Comparative Examples. It should be noted that the scope of the present invention is not limited to these Examples.

[0079] (Example 1)

[0080] Polyurethane (Coronate 4370, manufactured by Tosoh Corporation) was used as the resin material, a curing agent (Nippollan 4479, manufactured by Tosoh Corporation) was selected accordingly, and hollow particles (Matsumoto Microsphere FN-78D, manufactured by Matsumoto Oil and Fat Pharmaceutical Co., Ltd.) were mixed therein. The preparation was placed in a square 200×200 mm (200×200 mm 2 ) in a polishing pad mold and pre-cured in an oven at 120° C. for 10 minutes. After primary curing at 120° C. for 2 hours, the polishing pad was removed from the mold and secondary cured again at 120° C. for 8 hours. In this case, the thickness of the polishing pad was 1.5 mm.

[0081] A film (hydrophilic film) containing SiO2 was formed on the polishing pad obtained above by ALD, using 3DMAS as a precursor and H2O as a reactive gas to form SiO2 with a thickness of about 100 nm.

[0082] (Example 2)

[0083] The same procedure as in Example 1 was performed except that the thickness of the SiO2-containing film was adjusted to about 10 nm.

[0084] (Example 3)

[0085] The same steps as in Example 1 were performed except that the SiO 2 -containing film was changed to an Al 2 O 3 -containing film (hydrophilic film), TMA was used as a precursor and H 2 O was used as a reactive gas, and the film thickness was adjusted to about 100 nm.

[0086] (Example 4)

[0087] The same procedure as in Example 3 was performed except that the thickness of the Al 2 O 3 -containing film was adjusted to about 10 nm.

[0088] (Example 5)

[0089] The same steps as in Example 1 were performed except that the C content in the SiO 2 -containing film was reduced (1.0 at %), and ozone was used instead of H 2 O as a reactive gas to form a SiO 2 -containing film having a low C content.

[0090] (Example 6)

[0091] The same steps as in Example 1 were performed except that the C content in the SiO 2 -containing film was increased (23.4 atomic %), and a SiO 2 -containing film having a high C content was formed by reducing the amount of H 2 O supplied as a reactive gas.

[0092] (Comparative Example 1)

[0093] A pure polyurethane polishing pad was used. The preparation method was the same as the first half of Example 1 above, and no SiO2-containing film was formed.

[0094] (Comparative Example 2)

[0095] A polishing pad prepared by mixing polyurethane with a hydrophilic polymer (epoxy resin) was used. The same procedure as in the first half of Example 1 (except for film formation) was performed except that polyurethane (Coronate 4370, manufactured by Tosoh Corporation) and epoxy resin (JER834, manufactured by Mitsubishi Chemical Corporation) were mixed in a ratio of 7:3, and a curing agent (jERCURE FL052, manufactured by Mitsubishi Chemical Corporation) was selected accordingly and mixed therein.

[0096] (Comparative Example 3)

[0097] A polishing pad prepared by mixing polyurethane with a hydrophilic polymer (epoxy resin) was used in the same manner as in Comparative Example 2. The only difference from Comparative Example 2 was that the mixing ratio of polyurethane to epoxy resin was 5:5.

[0098] (Comparative Example 4)

[0099] A polyurethane polishing pad whose surface was sprayed with a hydrophilic resin was used. The polishing pad described in Comparative Example 2 was used, which was coated with a hydrophilic spray (MAGI-Poly(R), manufactured by Crystal Optics Inc.).

[0100] The evaluation results of each sample are shown in Table 1. The present example achieved a polishing rate and durability comparable to those of the comparative example (the determination value of each example was A or B).

[0101] [Table 1]

[0102] Table 1

[0103]

[0104] Table 1 (continued)

[0105]

[0106] The methods of the measurement and evaluation performed above will be described.

[0107] (Hardness measurement)

[0108] The hardness of the polishing pad was measured using a Type A durometer (ASKER rubber hardness tester Type A, manufactured by KOBUNSHI KEIKI CO., LTD.) The detailed measurement method was in accordance with Japanese Industrial Standard JIS K7215.

[0109] (Contact angle measurement)

[0110] The hydrophilicity of the polishing pad is quantified based on the contact angle. The contact angle before the polishing pad is worn and the contact angle after the polishing pad is worn for about 100 μm are measured. When 2 μL of pure water is dropped on the polishing pad, the contact angle is measured using a contact angle meter (DropMaster DM300, manufactured by Kyowa Interface Science Co., Ltd.). The detailed measurement method is based on Japanese Industrial Standard JIS R 3257.

[0111] (Film thickness measurement (measurement of D1 and D2))

[0112] The average thickness D1 and D2 of the hydrophilic film were measured as follows: First, the sponge-like porous body was cut into a square of 10 mm × 10 mm (when viewed from the top). In order to evaluate D1, the sponge-like porous body was then sliced ​​at 10% of the thickness of the sponge-like porous body in the thickness direction from the front surface portion to the rear surface portion of the sponge-like porous body, thereby obtaining a cross section. In addition, in order to evaluate D2, the sponge-like porous body was then sliced ​​at 50% of the thickness of the sponge-like porous body in the thickness direction from the front surface portion to the rear surface portion of the sponge-like porous body, thereby obtaining a cross section. The cut sample was observed by a scanning electron microscope (JSM-IT500HR, manufactured by JEOL Ltd.) to measure the thickness of the hydrophilic film on the inner wall of the pores present in the cross section. As a result of observing the cross section by a scanning electron microscope, when more than 50% of the pores in the cross section have a hydrophilic film, the thickness of the hydrophilic film was measured for each cross section using 20 pores having a hydrophilic film, and the average values ​​were expressed as D1 and D2. When less than 50% of the pores in the cross section have hydrophilic membranes, the values ​​of D1 and D2 are set to zero.

[0113] (Measurement of C content)

[0114] For the measurement of the C content (carbon content) of the oxide film in the pores of the polishing pad, a Si wafer on which a film was formed under the same conditions and with the same thickness was independently provided, and the film formed on the Si wafer was analyzed by XPS (X-ray photoelectron spectrometer) (QuanteraII, manufactured by ULVAC-PHI, Inc.) to measure the C content.

[0115] (Evaluation of polishing rate and polishing rate stability)

[0116] The polishing rate of the polishing pad is evaluated. The glass is polished for a predetermined time and the weight of the glass before and after polishing is measured. The polishing rate is calculated from the reduction in glass weight. Figure 3A and 3B The apparatus shown was used for polishing, and the polishing conditions were as follows.

[0117] Work piece: S-FSL5 (Ohara Co., Ltd.), φ50

[0118] Load applied to workpiece: 25kPa

[0119] Stage speed: 500rpm

[0120] Polishing time: 30 minutes

[0121] Abrasive: Cerium oxide (MIREK(R) K30-9, manufactured by Mitsui Mining & Smelting Co., Ltd.)

[0122] The polishing rate was evaluated under two conditions, namely, one condition when the polishing pad was new (before the accelerated durability test) and the other condition when the polishing pad was worn by about 100 μm in the accelerated durability test of the polishing pad to be described later (after the accelerated durability test). The polishing rate stability was evaluated by comparing the two conditions.

[0123] The polishing rate was evaluated as follows, and the evaluation of the polishing rate was preferably B or more.

[0124] A: 1.00μm / min or more

[0125] B: 0.70 μm / min or more and less than 1.00 μm / min

[0126] C: less than 0.70μm / min

[0127] Regarding the polishing rate stability, the rate ratio R is defined as follows, so that the stability is evaluated based on the R value, and the evaluation of the polishing rate stability is preferably B or more.

[0128] R = polishing rate in worn state / polishing rate in new state

[0129] A:R≥0.85

[0130] B:0.70≤R<0.85

[0131] C:R<0.70

[0132] (Evaluation of polishing pad durability)

[0133] The durability of the polishing pad is evaluated by performing an accelerated durability test. The accelerated durability test used in the present invention refers to the use of Figure 3A and 3B The test was conducted with the apparatus shown, where diamond grit was used in the workpiece to produce a situation where the polishing pad was worn by the diamond grit at an accelerated rate. The wear rate was taken as the durability of the polishing pad. The wear situation was as follows.

[0134] Workpiece: Diamond grit, #1200

[0135] Load applied to workpiece: 4kPa

[0136] Stage speed: 110rpm

[0137] Wear time: 30 minutes

[0138] The durability of the polishing pad is evaluated according to the following criteria based on the wear rate of the polishing pad when evaluated by the above method. The durability of the polishing pad is preferably B or more.

[0139] A: Wear rate of polishing pad ≤ 0.20μm / min

[0140] B: 0.20μm / min<wear rate of polishing pad≤0.40μm / min

[0141] C: 0.40μm / min<wear rate of polishing pad

[0142] As described above, the sponge-like porous body of the present invention can improve the hydrophilic property up to the inside of the porous body without impairing the elasticity and flexibility of the sponge-like porous body.

[0143] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A sponge-like porous body comprising a substrate having pores, wherein The inner wall of the pore has a hydrophilic film in a region from 0% depth to 20% or more depth of the thickness of the sponge-like porous body in the thickness direction from the front surface portion to the back surface portion; and The substrate comprises a foamed resin. 2 . The sponge-like porous body according to claim 1 , wherein the hydrophilic film is an oxide film.

3. The sponge-like porous body according to claim 2, wherein the material of the oxide film comprises one or a mixture of two or more selected from SiO2, Al2O3, TiO2, Ta2O5, HfO2 and RuO2. 4 . The sponge-like porous body according to claim 2 , wherein a C content in the oxide film is 0.5 atomic % or more and 25 atomic % or less. The sponge-like porous body according to claim 1 , wherein the substrate comprises at least one selected from the group consisting of polyurethane, polyether, and polyethylene. The sponge-like porous body according to claim 1 , wherein the substrate comprises polyurethane.

7. The sponge-like porous body according to claim 1, wherein When the average thickness of the hydrophilic film on the inner wall of the pores in the region of a depth of 0% or more and 20% or less of the thickness of the sponge-like porous body in the thickness direction from the front surface portion to the rear surface portion is represented as D1 and the average thickness of the hydrophilic film on the inner wall of the pores in the region (central portion) of a depth of 40% or more and 60% or less of the thickness of the sponge-like porous body in the thickness direction from the front surface portion to the rear surface portion is represented as D2, D1 and D2 satisfy all of the following inequalities: 10nm≤D1≤10μm, 10nm≤D2≤10μm, and 0.7×D2≤D1≤1.3×D2.

8. The sponge-like porous body according to claim 1, which has a hardness of 90 points or less as measured by a type A durometer.

9. The sponge-like porous body according to claim 1, which has a thickness of 0.1 mm or more.

10. The sponge-like porous body according to claim 1, which has a thickness of 0.5 mm or more. 11 . A polishing pad comprising the sponge-like porous body according to claim 1 . 12 . The polishing pad according to claim 11 , wherein the polishing rate of the glass is 0.70 μm / min or more before the accelerated durability test.

13. The polishing pad according to claim 11, wherein after the durability accelerated test, the polishing rate of the glass is 0.70 μm / min or more. 14 . The polishing pad according to claim 11 , wherein a value obtained by dividing the polishing rate of the glass after the accelerated durability test by the polishing rate of the glass before the accelerated durability test is 0.70 or more. 15 . The polishing pad according to claim 11 , wherein the wear rate is 0.40 μm / min or less in an accelerated durability test.

16. A liquid absorption pad comprising the sponge-like porous body according to any one of claims 1 to 10. 17 . A cleaning sponge comprising the sponge-like porous body according to claim 1 . 18 . A cultivation sponge comprising the sponge-like porous body according to claim 1 .

19. A polishing pad comprising a sponge-like porous body having a porous substrate, wherein in the sponge-like porous body, In the region from 0% depth to 20% or more depth of the thickness of the sponge-like porous body in the thickness direction from the front surface portion to the rear surface portion, the inner wall of the pore has a hydrophilic film; and wherein The front surface portion is used as a polishing surface for polishing an object to be polished with a polishing liquid.

20. A method for producing a sponge-like porous body, comprising: providing a substrate having pores; and A hydrophilic film is formed on the inner wall of the pore by atomic layer deposition (ALD). The substrate comprises at least one selected from polyurethane, polyether and polyethylene. 21 . The method for producing a sponge-like porous body according to claim 20 , wherein the providing includes forming through holes in the substrate.

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