Polishing pad and method for manufacturing glass plate

Abstract

The present invention relates to a polishing pad for polishing the surface of a glass plate, and a method for manufacturing a glass plate, the polishing pad having a plurality of convex rows arranged at intervals in a direction Y orthogonal to a direction X in which the convex rows extend, the convex row portion is composed of a boss extending in the direction X or a plurality of bosses arranged in the direction X in a mutually discrete manner, the width W of the convex row portion is 0.5-5 mm, the interval G between the convex row portions is 0.5-5 mm, and the rate of change D obtained by a measurement method P is 10 N / mm or less.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a polishing pad and a glass plate. Background Art

[0002] When manufacturing a glass substrate used in a flat panel display (FPD) such as a liquid crystal display (LCD) and an organic light-emitting diode (OLED), the surface of the glass substrate obtained by forming molten glass or cutting out a block of glass is usually polished by a polishing device.

[0003] In the grinding of the surface of such a glass substrate, a grinding liquid and a grinding pad containing free abrasive grains are used. Among them, the following technology is known: grooves or micropores are provided on the grinding surface of the grinding pad, and the free abrasive grains contained in the grinding liquid are maintained in the grooves or micropores of the grinding surface, thereby improving the grinding performance when grinding the surface of the glass substrate.

[0004] Patent document 1 describes an invention related to a polishing pad, which has a plurality of first grooves arranged in parallel on a polishing surface at predetermined intervals, a plurality of second grooves intersecting the first grooves, and a plurality of holes consisting of polishing liquid supply holes and polishing liquid suction holes arranged on the bottom surfaces of the first grooves and the second grooves.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: International Publication No. 2013 / 118578 Summary of the invention

[0008] Problems to be solved by the invention

[0009] On the other hand, if a polishing pad and a polishing liquid having grooves or micropores (hereinafter, also referred to as "groove portions") are used for a long time, deposits such as abrasive grains or glass products will gradually accumulate in the groove portions (hereinafter, this phenomenon will also be referred to as "clogging"), and the function of retaining abrasive grains will decrease. As a result, the polishing force of the polishing pad decreases, which may cause problems such as a decrease in the polishing accuracy of the glass substrate surface, the generation of polishing damage, and excessive heat caused by friction.

[0010] When the polishing pad is clogged, sometimes a process called dressing or sharpening is performed to remove deposits from the groove portion of the polishing pad. However, if the number of dressing processes is large, the operating rate of the polishing device decreases, and the overall operating efficiency decreases.

[0011] In view of the above-mentioned actual situation, the present invention provides a polishing pad whose polishing surface is not easily clogged during polishing. In addition, the present invention provides a method for manufacturing a glass substrate using the polishing pad.

[0012] Means for solving problems

[0013] As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by the following configuration.

[0014] [1] A polishing pad for polishing the surface of a glass plate, characterized in that the polishing pad has a plurality of convex columns, the plurality of convex columns are arranged at intervals in a direction Y orthogonal to a direction X in which the convex columns extend, the convex columns are composed of bosses extending in the direction X or a plurality of bosses discretely arranged in the direction X, the width W of the convex columns is 0.5 to 5 mm, the interval G between the convex columns is 0.5 to 5 mm, and the rate of change D obtained by the measurement method P described below is 10 N / mm or less.

[0015] [2] The polishing pad according to [1], wherein a ratio of the width W to the gap G is 0.2 to 2.0.

[0016] [3] The polishing pad according to [1] or [2], wherein the height of the convex row is 0.5 to 3.0 mm.

[0017] [4] The polishing pad according to any one of [1] to [3], wherein the polishing pad comprises a resin or a nonwoven fabric.

[0018] [5] A method for manufacturing a glass plate, characterized in that the polishing pad described in any one of [1] to [4] is pressed against the surface of the glass plate, and a polishing liquid containing abrasive grains is supplied between the glass plate and the polishing pad, while the polishing pad and the glass plate are slid relative to each other for polishing.

[0019] Effects of the Invention

[0020] According to the present invention, a polishing pad whose polishing surface is not easily clogged during polishing can be provided. In addition, according to the present invention, a method for manufacturing a glass substrate using the polishing pad can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIGS. 1( a ) and ( b ) are schematic diagrams showing an example of the structure of a polishing pad according to the first embodiment.

[0022] Figure 2 This is a schematic diagram of an apparatus for measuring the change rate D of a polishing pad using the measurement method P.

[0023] Figure 3It is a three-dimensional diagram of a pushing tool.

[0024] Figure 4 This is an enlarged view of the lower end of the pressing tool.

[0025] Figure 5 It is a diagram showing the positional relationship between the pressing tool and the convex row of the polishing pad.

[0026] Figure 6 It is a graph showing the relationship between the measurement result based on the measurement method P and the change rate D.

[0027] Figure 7 This is a schematic diagram showing an example of the structure of a polishing pad according to the second embodiment.

[0028] Figure 8 It is a schematic diagram showing another example of the structure of the polishing pad according to the second embodiment. DETAILED DESCRIPTION

[0029] Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments. Various modifications and substitutions can be made to the following embodiments without departing from the scope of the present invention.

[0030] In addition, the scales of the components described in the drawings are appropriately changed from the actual scales in order to facilitate the description.

[0031] In this specification, the numerical range represented by "~" means a range including the numerical values ​​recorded before and after "~" as the lower limit and the upper limit. In the numerical range recorded in stages in this specification, the upper limit or lower limit recorded in a certain numerical range can also be replaced by the upper limit or lower limit of the numerical range recorded in other stages. In addition, in the numerical range recorded in this specification, the upper limit or lower limit recorded in a certain numerical range can also be replaced by the value shown in the embodiment.

[0032] [Polishing pad]

[0033] The polishing pad involved in the present invention is a polishing pad for polishing the surface of a glass plate, wherein the polishing pad has a plurality of convex columns, the plurality of convex columns are arranged at intervals in a direction Y orthogonal to a direction X in which the convex columns extend, the convex columns are composed of bosses extending along the direction X or a plurality of bosses discretely arranged along the direction X, the width W of the convex columns is 0.5 to 5 mm, the interval G between the convex columns is 0.5 to 5 mm, and the rate of change D obtained by the measurement method P described later is 10 N / mm or less.

[0034] Conventionally, in the case of a polishing pad having grooves on the polishing surface for the purpose of improving the polishing performance by retaining abrasive grains, it is expected that the polishing surface may be worn or damaged due to the reduction in the contact area, and therefore, a material having relatively high rigidity and strength is selected as a material constituting the polishing pad. On the other hand, there is no attention paid to the relationship between the above-mentioned clogging problem in the polishing pad having grooves on the polishing surface and the rigidity of the constituent material of the polishing pad.

[0035] In contrast, in the polishing pad according to the present invention, the width W of the convex row and the interval G between the convex rows are within a predetermined range and the change rate D is below a predetermined value, thereby suppressing the occurrence of clogging in the groove portion of the polishing surface.

[0036] The details of the reasons why the grinding pad of the present invention has the above-mentioned effect are not clear, but it is speculated as follows. It is obvious from the measurement method P described later that the above-mentioned rate of change D represents the relationship between the force applied to the grinding pad, especially the convex column portion, and its movement amount. The smaller the rate of change D is, the more it means that the convex column portion is composed of a material that is easy to move even with a small force. Therefore, during the period when the grinding pad of the present invention is used to grind an object such as a glass substrate, since the rate of change D is relatively small, the convex column portion in contact with the object in the grinding surface is greatly deflected. As a result, the replacement of abrasive grains at the upper part of the boss that contacts the glass plate during grinding is promoted, so it is speculated that the occurrence of clogging is suppressed.

[0037] As described above, the polishing pad according to the present invention can suppress the occurrence of clogging, thereby stabilizing the polishing force, suppressing polishing damage, and omitting the dressing work, thereby achieving a significant improvement in the productivity of the polished object.

[0038] Hereinafter, preferred embodiments of the polishing pad according to the present invention will be described with reference to the drawings.

[0039] [First embodiment]

[0040] FIGS. 1( a ) and ( b ) are schematic diagrams showing an example of the structure of a polishing pad according to a first embodiment of the present invention.

[0041] FIG. 1( a ) is a plan view of a polishing pad 10 according to the first embodiment, and FIG. 1( b ) is a cross-sectional view of the polishing pad 10 taken along line AA shown in FIG. 1( a ).

[0042] As shown in Fig. 1(a), the polishing pad 10 according to the present embodiment has a plurality of convex columns 12. The convex columns 12 are each composed of a boss 14 extending along a direction X (the direction indicated by the arrow X in the figure). The plurality of convex columns 12 are arranged at intervals in a direction Y (the direction indicated by the arrow Y in the figure) orthogonal to the direction X.

[0043] As shown in Fig. 1 (a) and (b), a groove 16 extending in the direction X is formed between two adjacent convex rows 12. That is, the convex rows 12 and the grooves 16 are arranged alternately along the direction Y.

[0044] The convex row 12 (convex platform 14) extends from the base end 12B to the top end 12A along the direction Z (the direction indicated by the arrow Z in the figure) indicating the thickness direction of the polishing pad 10. The top end 12A of the convex row 12 contacts the surface of the glass substrate and polishes the surface of the glass substrate.

[0045] As described above, the polishing pad 10 according to the present embodiment includes a polishing surface having a stripe-shaped pattern in which a plurality of convex rows 12 are arranged in parallel.

[0046] In the case of the polishing pad 10 shown in the top view 1 (a), the outer periphery of the polishing surface formed by the plurality of convex columns 12 is rectangular, but the shape of the polishing surface of the polishing pad involved in this embodiment is not limited to a rectangular shape. The outer periphery of the polishing surface of the polishing pad may also be a circular shape, an elliptical shape, a polygonal shape other than a rectangular shape, etc.

[0047] In this embodiment, the width W of the convex column 12 is 0.5 to 5 mm. The width W of the convex column 12 means the distance from one end to the other end of the convex column 12 in the direction Y when the polishing pad 10 is viewed from above. In addition, the widths of the plurality of convex columns are preferably substantially constant.

[0048] The width W of the convex row 12 is preferably 0.5 to 2.5 mm, and more preferably 0.5 to 2.0 mm, in terms of better clogging suppression performance and polishing performance.

[0049] Regarding the width W of the convex column 12, the width along the direction Y at the top 12A of the convex column 12 is measured at 10 or more positions arbitrarily selected along the direction X, and the obtained measured values ​​are arithmetic averaged to obtain the width W of the convex column 12 as the average value.

[0050] The same is true for the interval G between the convex columns 12. For two adjacent convex columns 12 sandwiching the groove 16, 10 or more positions are arbitrarily selected along the direction X, and the distance between the two opposite sides at the top ends 12A of the two convex columns 12 at the selected positions along the direction X is measured. The measured values ​​are arithmetic averaged to calculate the interval G between the convex columns 12.

[0051] In this way, the width W of the convex row 12 and the interval G between the convex row 12 are both obtained based on the distance measured on the polished surface.

[0052] In addition, regarding the height H of the convex column portion 12, the convex column portion 12 is cut along the YZ plane perpendicular to the direction X of the convex column portion 12 at positions more than 10 points arbitrarily selected along the direction X, and the cut section is observed using a scanning electron microscope (SEM: Scanning Electron Microscope). The height of each convex column portion is measured based on the obtained observation image, and the obtained measured values ​​are arithmetic averaged to calculate the height H of the convex column portion 12 as the average value.

[0053] In this embodiment, the interval G between the convex rows 12 is 0.5 to 5 mm. The interval G between the convex rows 12 means the distance between two adjacent convex rows 12 in the direction Y when the polishing pad 10 is viewed from above, and is synonymous with the width of the groove 16 in the direction Y.

[0054] The interval G between the convex rows 12 is preferably 0.5 to 2.5 mm, more preferably 0.5 to 2.0 mm, in terms of better clogging suppression performance and polishing performance. In addition, there are a plurality of intervals between the convex rows, but they are preferably substantially constant.

[0055] The ratio (W / G) of the width W of the convex column 12 to the interval G between the convex column 12 is, for example, 0.2 to 2.0, preferably 0.2 to 1.5, and more preferably 0.5 to 1.5 in order to ensure the discharge of the polishing liquid containing abrasive grains and expand the polishing action area.

[0056] The height H of the convex row 12 is, for example, 0.5 to 3.0 mm, preferably 1.0 to 2.5 mm, and more preferably 1.3 to 2.0 mm.

[0057] Furthermore, the ratio (H / W) of the height H of the convex row 12 to the width W of the convex row 12 is preferably 1.0 to 2.5, and more preferably 1.5 to 2.0.

[0058] The cross-sectional shape when the convex column is cut by a plane perpendicular to the direction X can be a rectangle as shown in FIG. 1( b), or a trapezoid with a base end wider than a top end, or a trapezoid with a base end narrower than a top end. In addition, the periphery other than the base end and the top end of the cross-sectional shape can also be a curve. The cross-sectional shape is preferably a rectangle or a trapezoid with a base end wider than a top end, and more preferably a rectangle.

[0059] <Rate of change D>

[0060] In the polishing pad according to the present embodiment, the rate of change D obtained by the following measuring method P is 10 N / mm or less.

[0061] Measurement method P: A convex column portion arranged at the end of one side in the direction Y among a plurality of convex columns is selected as the measurement object, and a pushing tool is brought into contact with an area of ​​0.6±0.1 mm from the top end of the selected convex column portion toward the base end side in the end surface in the direction Y that is not opposite to other convex columns of the selected convex column portion, and is pushed along the direction Y at a speed of 0.5 mm / min, and the movement amount (unit: mm) of the pushing tool and the load (unit: N) acting on the pushing tool are measured. A curve graph is prepared with the movement amount as the horizontal axis and the load as the vertical axis. An approximate straight line of the above curve graph in the range from the contact of the pushing tool with the above area to the distance of half the width W of the selected convex column portion is derived by the least squares method, and the slope of the derived approximate straight line is set as the rate of change D (N / mm).

[0062] The change rate D of the polishing pad is preferably 8 N / mm or less, and more preferably 6 N / mm or less, in terms of better performance in suppressing clogging.

[0063] The change rate D of the polishing pad is, for example, 0.5 N / mm or more, and is preferably 1 N / mm or more in terms of better durability of the polishing pad itself.

[0064] Hereinafter, after explaining a specific example of a pressing tool used in the measuring method P, the measuring method P will be explained in more detail.

[0065] (Push tool)

[0066] Figure 2 This is a schematic diagram of an apparatus for measuring the change rate D of a polishing pad using the measurement method P.

[0067] The pressing tool 110 is constituted Figure 2 The device of the measuring device 100 shown is used when measuring the change rate D of the polishing pad using the measuring method P. Specifically, when measuring the change rate D of the polishing pad using the measuring device 100, the pressing tool 110 presses the convex column 12s arranged at the end of one side in the direction Y among the plurality of convex columns of the sample S of the polishing pad at a constant speed. In the illustrated pressing tool 110, the pressing direction (hereinafter referred to as the pressing direction) is the downward direction in the vertical direction, and is the downward direction in the direction Y on the paper.

[0068] Hereinafter, an example of a suitable structure of the pressing tool 110 will be described.

[0069] Figure 3 It is a perspective view of the pressing tool 110 . Figure 4 It is an enlarged view of the lower end portion of the pressing tool 110 . Figure 5 1 is a diagram showing the positional relationship between the pressing jig 110 and the convex row of the polishing pad.

[0070] The pressing tool 110 is made of a material having a hardness sufficient to press the convex column of the polishing pad, for example, a metal member made of a metal material having a Young's modulus of 170 GPa or more. The pressing tool 110 is substantially L-shaped when viewed from the side. Figure 3 As shown, it has a base portion 112 and a pushing portion 114 .

[0071] The base 112 is a part provided for connecting the pressing tool 10 to the driving device. Figure 2 and Figure 3 As shown, the lower end of the connecting shaft 120 extending downward in the vertical direction, i.e., the direction Y, from the above-mentioned driving device is fixed to a predetermined position of the base 112. The fixing position of the connecting shaft 120 in the base 112 is not particularly limited, but it is preferably fixed to the central part of the base 112 in a plan view. In addition, the base 112 is square in a plan view and has a sufficient thickness as the base 112. There are no particular limitations on the planar dimensions and thickness of the base 112, but for example, the planar dimensions may be: about 25 mm on one side and about 5 mm in thickness.

[0072] The pressing portion 114 is a columnar portion protruding from the base 112, and is, for example, in the shape of a substantially rectangular parallelepiped. When the pressing tool 110 is being used, Figure 2 As shown, the push portion 114 protrudes downward in the direction Y. Figure 2 The pushing portion 114 extends in the direction X from one end of the base 112 to the other end thereof. In other words, the pushing portion 114 has the same length as the base 112 in the direction X. In addition, the length of the pushing portion 114 in the direction X is designed to be sufficiently longer than the length of the convex column portion of the sample of the polishing pad in the direction X.

[0073] In addition, in the direction Z( Figure 2 In the left-right direction of the paper surface in FIG. 1 , the width of the top end portion 114t of the pushing portion 114 is shorter than the width of the base portion 112, and specifically, is about half the width of the base portion 112. That is, in the direction Z, one end surface 114a of the pushing portion 114 and one end surface 112a of the base portion 112 are continuously located on the same plane, while the other end surface 114b of the pushing portion 114 is located at a position retreated from the other end surface 112b of the base portion 112.

[0074] Moreover, if Figure 3 and Figure 4As shown, a rectangular cutout 116 is provided at a corner of the top end 114t (the lower end of the pushing tool 10 when in use) of the pushing portion 114, which is located on the other end face 114b side of the pushing portion 114. In other words, a step is formed at the top end side of the other end face 114b of the pushing portion 114, and the cutout 116 is formed by the step. The size of the cutout 116 is about 0.6 mm from the other end face 114b in the direction Z, and about 3 mm from the top end of the pushing portion 114 in the direction Y. In addition, as shown in FIG. Figure 3 and Figure 4 As shown, the corner portion between the other end surface 114b of the pressing portion 114 and the cutout portion 116 and the corner portion between the end surface in the direction Y and the end surface in the direction Z of the cutout portion 116 are not chamfered but are bent at substantially right angles.

[0075] It should be noted that the cutout portion 116 is continuous in the direction X from one end to the other end of the pressing portion 114 .

[0076] (Measurement Method P)

[0077] A method P for measuring the rate of change D of the polishing pad will be described using an operation example of the pressing tool 10 configured as described above as a representative example.

[0078] When the change rate D of the polishing pad is measured by the measuring method P using the pressing tool 10, as shown in FIG. Figure 2 As shown in FIG. 1 , a sample of a polishing pad (hereinafter referred to as sample S) is mounted on the side of a holding tool 122. The holding tool 122 is a metal block having a substantially rectangular parallelepiped shape and a rectangular side surface (hereinafter referred to as a holding surface 124). The holding tool 122 is used in a state where it is mounted on a mounting metal member fixed to a workbench by fasteners such as bolts. When the holding tool 122 is used, as shown in FIG. Figure 2 As shown, the retaining surface 124 is orthogonal (upright) relative to the direction Z (horizontal direction).

[0079] The sample S is a polishing pad to be measured, and has a square shape with a side of about 15 mm in a plan view. In the sample S, as in the polishing pad 10 shown in FIG. 1( b ), the convex columns 12 extend in a direction Z, and a plurality of convex columns 12 are arranged at a constant interval in a direction Y orthogonal to the direction Z in which the convex columns 12 extend on the surface of the sample S.

[0080] It should be noted that the sample S may be a pad segment cut out from a polishing pad to be measured.

[0081] Then, the sample S is held by the holding tool 122 by being adhered to the holding surface 124 by an adhesive or the like. Figure 2As shown, the sample S is held by the holding tool 122 in a state where the direction (direction Y) in which the plurality of convex rows 12 are arranged, that is, the direction orthogonal to the extending direction of the convex rows 12 on the surface of the sample S is along the vertical direction.

[0082] After the sample S is fixed to the holding tool 122, the pushing tool 110 is Figure 2 As shown in FIG. 1 , the push tool 110 is placed just above the sample S. Thereafter, the driving device connected to the push tool 110 is operated, whereby the push tool 110 is lowered, and soon after, the top end portion (lower end portion) of the push portion 114 provided in the push tool 110 abuts against the sample S. At this time, the notch portion 116 formed at the top corner portion of the push portion 114 is hooked to the free end portion (top end portion) of the convex column portion 12s disposed at the end of one side in the direction Y among the plurality of convex column portions 12 provided on the sample S, and is engaged with the convex column portion 12s.

[0083] In more detail, Figure 4 As shown, the cutout portion 116 provided on the end surface 114b on the holding tool 122 side of the pressing portion 114 of the pressing tool 110 abuts against the free end (top end) of the convex column portion 12s, and the end surface of the cutout portion 116 in the direction Y abuts against the upper surface of the convex column portion 12s (the end surface in the direction Y that is not opposite to other convex columns 12). At this time, the area of ​​the upper surface of the convex column portion 12s that abuts against the cutout portion 116 is an area of ​​0.6±0.1 mm from the top end of the convex column portion 12s toward the base end side. In addition, as shown in FIG. Figure 5 As shown, the pressing portion 114 contacts the convex row 12 s from one end to the other end of the sample S in the direction X of the pressing tool 110 , in other words, contacts the entire range of the convex row 12 s in the direction X. Figure 5 This is a diagram of the convex row 12s viewed from above, in which the push portion 114 abutting against the convex row 12s is shown in dashed lines. As shown in the figure, the push portion 114 abuts against a region of 0.6 mm from the tip toward the base end of the convex row 12s, and applies a load downward (in the direction Y from the front to the back of the paper).

[0084] Afterwards, the pushing tool 110 continues to descend at a constant speed through the above-mentioned driving device. Thus, the pushing tool 110 continues to press the convex column 12s downward along the direction Y while maintaining the state in which the notch 116 of the pushing portion 114 is engaged with the convex column 12s in the sample S. At this time, the load (pushing load) acting on the pushing tool 110 is measured successively by the load sensor built into the above-mentioned driving device. In addition, during the descent of the pushing tool 110, its movement amount, in detail, the movement amount of the above-mentioned connecting shaft 120, is measured successively by the sensor built into the above-mentioned driving device.

[0085] exist Figure 6 An example of a graph showing the relationship between the measurement result based on the measurement method P and the change rate D is shown in FIG. Figure 6 In the graph shown, the horizontal axis represents the movement amount M (unit: mm) of the pressing tool 110 measured by the above method, and the vertical axis represents the load L (unit: N) acting on the pressing tool 110. Figure 6 In FIG. 1 , a curve C showing the relationship between the measured movement amount M of the pressing tool 110 and the load L acting on the pressing tool 110 is shown by a solid line. Figure 6 In the figure, “M0” represents the position of the pressing tool 110 when the pressing tool 110 moves and the end surface of the uppermost convex row 12s abuts against the stepped surface of the pressing portion 114, and “M H " indicates the position where the amount of movement from M0 becomes half the width W of the convex row 12s. H The curve C in the range of , is derived by the least squares method. Approximate straight line A (refer to Figure 6 ), and the slope of the derived approximate straight line A is set to the rate of change D (N / mm).

[0086] It should be noted that the use of Figure 2~Figure 5 The measuring method of the pushing tool 110 shown is only an example of the measuring method P. As long as the convex column portion abutting against the pushing tool is a convex column portion at the end of one side arranged in the Y direction among multiple convex columns, the contact range of the pushing tool is an area of ​​0.6±0.1mm from the top end toward the base end side in the end surface of the above-mentioned convex column portion in the direction Y that is not opposite to other convex columns, the moving speed of the pushing tool is constant before and after the abutment with the above-mentioned convex column portion, and the measuring method can measure the movement amount of the pushing tool during the movement and the load acting on the pushing tool, the change rate D of the polishing pad can be measured as the measuring method P.

[0087] The material constituting the polishing pad involved in the present embodiment can be appropriately selected and used from known polishing pad materials according to the change rate D of the purpose. As the structural material of the polishing pad, for example, resins such as non-woven fabrics and polyurethanes can be cited. The resin may be a foam or may not be a foam. The polishing pad preferably includes at least one of a resin and a non-woven fabric.

[0088] The polishing pad according to the present embodiment may be composed of a single layer or a laminate having a plurality of layers as long as the change rate D is within a predetermined range. The materials constituting each layer of the laminate may be the same or different and can be appropriately selected and used from the above materials.

[0089] The material constituting the polishing pad is preferably a material having an A hardness of 10 to 80 degrees, and more preferably a material having an A hardness of 20 to 65 degrees. The A hardness can be measured using a rubber hardness meter by a method in accordance with JIS K 6253 (2012).

[0090] The polishing pad is preferably made of a material having a Young's modulus of 0.1 to 20 MPa based on ASTM material testing standards, and more preferably a material having a Young's modulus of 0.2 to 10 MPa based on ASTM material testing standards.

[0091] [Second embodiment]

[0092] exist Figure 7 An example of the structure of the polishing pad according to the second embodiment of the present invention is shown in FIG.

[0093] Figure 7 It is a plan view of the polishing pad 20 according to the second embodiment.

[0094] like Figure 7 As shown, the polishing pad 20 according to this embodiment has a plurality of convex rows 22. Each convex row 22 is composed of a plurality of bosses 24 discretely arranged along the direction X. The plurality of convex rows 22 are arranged at intervals in the direction Y orthogonal to the direction X.

[0095] like Figure 7 As shown in FIG. 1 , a first groove 26 extending in the direction X is formed between two adjacent convex rows 22 . That is, the convex rows 22 and the first grooves 26 are arranged alternately along the direction Y.

[0096] In addition, the second groove 28 intersecting the first groove 26 at an angle of 45° is formed between two adjacent bosses 24. That is, the bosses 24 and the second grooves 28 are arranged alternately along the direction X.

[0097] The convex row 22 and the boss 24 extend from the base end to the tip end along the direction Z indicating the thickness direction of the polishing pad 20. The tip end of the convex row 22 contacts the surface of the glass substrate and polishes the surface of the glass substrate.

[0098] so, Figure 7 The polishing pad 20 shown in the figure has a polishing surface having a plurality of projections 24 arranged in a direction X and in a direction intersecting the direction X in an oblique lattice pattern.

[0099] exist Figure 8 Another example of the structure of the polishing pad according to the second embodiment of the present invention is shown in FIG.

[0100] Figure 8 It is a plan view of the polishing pad 30 according to the second embodiment.

[0101] like Figure 8 As shown, the polishing pad 30 according to the present embodiment has a plurality of convex rows 32. Each convex row 32 is composed of a plurality of bosses 34 discretely arranged along the direction X. The plurality of convex rows 32 are arranged at intervals in the direction Y orthogonal to the direction X.

[0102] like Figure 8 As shown in FIG. 1 , a first groove 36 extending in the direction X is formed between two adjacent convex rows 32 . That is, the convex rows 32 and the first grooves 36 are arranged alternately along the direction Y.

[0103] In addition, a second groove 38 orthogonal to the first groove 36 is formed between two adjacent bosses 34. That is, the bosses 34 and the second grooves 38 are arranged alternately along the X direction.

[0104] The convex row 32 and the boss 34 extend from the base end to the tip end along the direction Z indicating the thickness direction of the polishing pad 30. The tip end of the convex row 32 contacts the surface of the glass substrate and polishes the surface of the glass substrate.

[0105] so, Figure 8 The polishing pad 30 shown in the figure has a polishing surface having a grid-like pattern in which a plurality of bosses 34 are arranged in parallel in the X direction and the Y direction.

[0106] In this embodiment, when the polishing pad is viewed from above, the width W of the projections constituting the convex rows extending along the direction X is L For example, it is 0.5 to 5.0 mm, preferably 0.5 to 3.0 mm, and more preferably 0.5 to 2.5 mm in terms of better clogging suppression performance and polishing performance.

[0107] It should be noted that, as shown in the figure, the width W of the boss L It means the distance between two sides which are the boundaries with the second groove and face each other among the four sides constituting the outer periphery of the boss.

[0108] In addition, in the present embodiment, when the polishing pad is viewed from above, in the convex row extending along the direction X, the interval G between two adjacent convex lands is L In terms of better clogging suppression performance and polishing performance, the diameter is, for example, 0.5 to 5.0 mm, preferably 0.5 to 3.0 mm, and more preferably 0.5 to 2.5 mm.

[0109] It should be noted that, as shown in the figure, the interval G between two adjacent bosses is L It means the distance between the side of one boss and the side of the other boss that are opposed to each other with the second groove interposed therebetween.

[0110] In this embodiment, the width W of the above-mentioned boss is L Relative to the distance G between two adjacent bosses L The ratio (W L / G L ) is, for example, 0.2 to 4.0, and is preferably 0.5 to 2.0 in order to ensure the discharge of the polishing liquid containing the abrasive and increase the polishing action area.

[0111] Regarding the polishing pad involved in the second embodiment, the shape and arrangement of the convex column portions other than the above, such as the width W of the convex column portions and the interval G between the convex column portions, the change rate D and the constituent materials, including their preferred embodiments, are the same as those of the polishing pad involved in the first embodiment.

[0112] Hereinafter, regarding the polishing pad according to the present invention including the first embodiment and the second embodiment, a method for manufacturing the polishing pad and uses thereof will be described.

[0113] [Manufacturing method of polishing pad]

[0114] The polishing pad of the present invention can be manufactured by a known method. For example, a plurality of grooves extending in one direction are formed at intervals by cutting the surface of a sheet material composed of the constituent material of the polishing pad exemplified above, thereby forming a convex column portion composed of bosses extending in the above-mentioned one direction. In addition, a plurality of grooves extending in a first direction and a plurality of grooves extending in a second direction intersecting the first direction are formed, thereby forming a convex column portion extending in the first direction and composed of a plurality of bosses discretely arranged along the first direction.

[0115] In the convex row forming step, by changing the width and pitch of each groove, the width W of the convex row and the interval G between the convex rows can be adjusted. In addition, by changing the width and pitch of each groove and selecting the structural material of the polishing pad, the change rate D of the polishing pad can be adjusted.

[0116] [Method for manufacturing glass plate]

[0117] The polishing pad according to the present invention can be used in a method for manufacturing a glass plate in which the surface of the glass plate is polished using the polishing pad.

[0118] As a method for manufacturing a glass plate according to the present invention, for example, the following method can be cited: the polishing pad according to the present invention is pressed against the surface of a glass plate, and a polishing liquid containing abrasive grains is supplied between the glass plate and the polishing pad while the polishing pad and the glass plate are slid against each other for polishing.

[0119] By polishing the surface of a glass plate using the polishing pad according to the present invention, minute irregularities and undulations can be removed, and a glass plate satisfying the flatness required as a glass plate for FPD, for example, can be manufactured.

[0120] Examples of the glass plate to be polished include glass plates used in FPDs such as plasma displays, LCDs, and OLEDs.

[0121] The size and shape of the glass plate can be appropriately selected depending on the application.

[0122] The shape of the glass plate is, for example, a rectangular shape, and examples of its size include a size of 100 to 3000 mm on one side.

[0123] The thickness of the glass plate varies depending on the application, but in the case of a glass plate for FPD, it is preferably 0.2 to 0.7 mm, and more preferably 0.4 to 0.5 mm.

[0124] Examples of the polishing liquid include a fluid containing abrasive grains and a dispersion medium of the abrasive grains.

[0125] As the abrasive grains, colloidal silica or cerium oxide is preferred.

[0126] The average particle size of the abrasive grains is, for example, 0.5 to 1.5 μm. Here, the average particle size of the abrasive grains means an average particle size measured by a laser diffraction scattering method, and can be measured using a laser diffraction scattering type particle size distribution measuring device.

[0127] Examples of the dispersion medium for the abrasive include water and an organic solvent, and water is preferred.

[0128] The content of the abrasive grains in the polishing liquid is, for example, 5 to 40% by mass.

[0129] As a polishing device used for polishing a glass plate, for example, there can be cited a device including a workpiece platform for holding the lower surface of the glass plate via an adsorption sheet, a polishing platform for mounting a polishing pad, a rotating shaft for rotating the polishing platform, and a polishing liquid supply unit for supplying polishing liquid to the polishing pad.

[0130] The rotating shaft rotates around the rotation axis and revolves around the revolution axis through the driving unit. The grinding platform rotates and revolves along with the rotation and revolution of the rotating shaft. It should be noted that the rotation of the grinding platform can also be only revolving or only rotating. Revolution refers to the rotational motion of the grinding platform rotating along a circular orbit around the revolution axis.

[0131] The polishing liquid supply unit supplies the polishing liquid between the polishing surface of the polishing pad and the surface of the glass plate.

[0132] If the above-mentioned polishing device is put into operation, the polishing surface of the polishing pad is pressed against the polished surface of the glass plate, and polishing liquid is supplied between the polishing surface of the polishing pad and the surface of the glass plate. Through the rotation and revolution of the polishing pad, the polishing pad and the glass plate slide against each other, and the polishing force of the abrasive grains is added to polish the surface of the glass plate.

[0133] The manufacturing method of the glass plate of the present invention can also be applied to the grinding method and grinding device of the glass plate other than the above. The direction in which the grinding pad and the glass plate slide relative to each other is not limited to the rotation direction, but also can be the reciprocating direction. In addition, the grinding device can also have a plurality of grinding pads.

[0134] The polishing device may be a batch type polishing device or a continuous type polishing device that polishes the surface of the glass plate being conveyed.

[0135] Examples of steps other than the polishing step in the method for producing a glass plate include a forming step of forming molten glass into a plate shape by a float process or the like and a cutting step of cutting the plate-shaped glass into glass plates of a predetermined size.

[0136] [Example]

[0137] The present invention is specifically described below using examples. However, the present invention is not limited to the following examples. Examples 2, 4, and 9 are examples, and Examples 1, 3, and 5 to 8 are comparative examples.

[0138] (Example 1)

[0139] A laminated body composed of a base layer made of material 1 with a thickness of 2.1 mm and a soft polyurethane layer with a thickness of 0.3 mm was prepared. The dimensions of the laminated body were 15 mm in length and 15 mm in width, and the total thickness was 2.4 mm. As shown in Table 2 described below, material 1 was a nonwoven fabric.

[0140] A groove having a width of 1 mm and a depth of 1.6 mm extending in a straight line in the first direction was formed by cutting on the surface of the soft polyurethane layer side of the laminate. A plurality of grooves were formed at a pitch of 4 mm to produce a polishing pad having a polishing surface with a stripe pattern, as shown in FIG. 1( a ), in which a plurality of convex columns consisting of bosses extending in the X direction were arranged at intervals in the Y direction.

[0141] The width W of the convex row portion, the interval G between the convex row portions, and the height H of the convex row portion on the polishing surface of the produced polishing pad are shown in Table 1 described below.

[0142] (Examples 2~7)

[0143] In addition to using a base layer made of the material shown in Table 1 as a base layer constituting the stack, and changing the shape and spacing of the grooves formed by cutting so as to form a grinding surface having a width W and a spacing G of convex columns as shown in Table 1, grinding pads having a grinding surface with a striped pattern were prepared according to the method described in Example 1.

[0144] (Example 8)

[0145] A polishing pad having a flat polishing surface was produced according to the method described in Example 1, except that the cutting process in Example 1 was not performed and the grooves were not formed.

[0146] (Example 9)

[0147] A laminated body composed of a nonwoven fabric substrate layer having a thickness of 2.1 mm and a soft polyurethane layer having a thickness of 0.3 mm was prepared. The dimensions of the laminated body were 15 mm in length and 15 mm in width, and the total thickness was 2.4 mm.

[0148] The surface of the soft polyurethane layer side of the laminate is provided with a plurality of first grooves extending in a straight line in a first direction and a plurality of second grooves extending in a straight line in a second direction with an intersection angle of 45° with the first direction by cutting. The first grooves and the second grooves are both 1.5 mm wide, 1.6 mm deep, and 3 mm apart. Thus, the laminate is manufactured. Figure 7 The polishing pad shown has a polishing surface in an oblique grid shape, in which a plurality of convex rows composed of a plurality of convex lands arranged discretely in the direction X are arranged at intervals in the direction Y.

[0149] (Determination of rate of change D)

[0150] According to the above determination method P, use Figure 2~Figure 5 The change rate D of the polishing pad of each example was measured by using the pressing tool shown in the figure. The measurement results are shown in Table 1.

[0151] (Grinding test)

[0152] The above-mentioned polishing pad was fixed to the lower platform of the batch-type single-sided polishing machine by double-sided adhesive tape. In addition, an alkali-free glass plate with a thickness, vertical and horizontal dimensions of 0.5 mm × 300 mm × 300 mm was installed on the film frame to which the self-adsorbing resin sheet was attached. In this state, a polishing liquid containing cerium oxide abrasive particles with an average particle size of 1 μm was supplied between the glass plate and the polishing pad, while the surface pressure was 100 g / cm 2 Milling was performed for a total of 12 hours.

[0153] The surface of the polishing pad after the polishing test was observed visually and under a microscope, and the clogging of the polishing pad was evaluated based on the following evaluation criteria based on the observation results of the polishing pad surface.

[0154] (Clogging Evaluation Criteria)

[0155] ○…Almost no clogging occurred.

[0156] ×… Significant clogging occurred.

[0157] Table 1 shows the polishing surface pattern, material, shape of the convex row, measured value of the change rate D, and evaluation results of clogging of the polishing pad after the polishing test of the polishing pad prepared in each example. It should be noted that the evaluation results of Examples 1 to 8 are shown for the evaluation of clogging of the polishing pad.

[0158] In the table, the column "Polishing Surface Pattern" shows the pattern shape of the polishing surface formed by the projections, and "No Pattern" means that the polishing surface is a flat surface without a concavo-convex structure.

[0159] In addition, the type, A hardness, density and Young's modulus of materials 1 to 3 constituting each polishing pad are shown in Table 2. The A hardness of each material was measured using a rubber hardness meter in accordance with the method of JIS K 6253 (2012). The density of each material was measured using a precision electronic balance by cutting out a sample of a unit area (10 cm×10 cm).

[0160]

Table 1

[0161]

Table 2

[0162] As shown in Table 1 above, in the polishing pads of Examples 2 and 4, where the width W is 0.5 to 5 mm, the interval G is 0.5 to 5 mm, and the rate of change D is 10 N / mm or less, no clogging occurs on the polishing surface, and the clogging suppression performance is excellent. In contrast, in the polishing pads of Examples 1, 3, and 5 to 8, where the rate of change D exceeds 10 N / mm, significant clogging occurs on the polishing surface, and the clogging suppression performance is insufficient. In addition, the polishing pad of Example 9, where the width W is 0.5 to 5 mm, the interval G is 0.5 to 5 mm, and the rate of change D is 10 N / mm or less, no clogging occurs on the polishing surface, and it is presumed that the clogging suppression performance is excellent.

[0163] This application is based on Japanese patent application No. 2023-125350 filed on August 1, 2023, the contents of which are incorporated herein by reference.

[0164] Description of Reference Numerals

[0165] 10, 20, 30 abrasive pads;

[0166] 12, 12s, 22, 32 convex columns;

[0167] 12A Top;

[0168] 12B base end;

[0169] 14, 24, 34 bosses;

[0170] 16 slots;

[0171] 26, 36 first slot;

[0172] 28, 38 second slot;

[0173] 100 Measurement device;

[0174] 110 Pushing tools;

[0175] 112 base;

[0176] 114 Pushing part;

[0177] 116 incision;

[0178] 120 connecting shaft;

[0179] 122 Keep Tools;

[0180] 124 Keep Face;

[0181] S sample.

Claims

1. A polishing pad for polishing a surface of a glass plate, characterized in that: The polishing pad has a plurality of convex columns, The plurality of convex rows are arranged at intervals in a direction Y orthogonal to a direction X in which the convex rows extend. The convex row portion is composed of a boss extending along the direction X or a plurality of bosses arranged discretely along the direction X. The width W of the convex column is 0.5-5 mm. The interval G between the convex columns is 0.5 to 5 mm. The change rate D obtained by the following measurement method P is 10 N / mm or less, Measurement method P: A convex column portion arranged at the end of one side in the direction Y among the multiple convex columns is selected as a measurement object, a pushing tool is brought into contact with an area of ​​0.6±0.1 mm from the top end toward the base end side of the selected convex column portion in the end surface in the direction Y that is not opposite to other convex columns, and the pushing tool is pushed along the direction Y at a speed of 0.5 mm / min, and the movement amount (unit: mm) of the pushing tool and the load (unit: N) acting on the pushing tool are measured; a curve graph with the movement amount as the horizontal axis and the load as the vertical axis is prepared; an approximate straight line of the curve graph in the range from the contact of the pushing tool with the area to the movement distance of half the width W is derived by the least squares method, and the slope of the derived approximate straight line is set to the rate of change D (N / mm).

2. The polishing pad according to claim 1, wherein The ratio of the width W to the interval G is 0.2 to 2.

0.

3. The polishing pad according to claim 1, wherein The height of the convex column is 0.5~3.0mm.

4. The polishing pad according to claim 1, wherein The polishing pad includes a resin or a non-woven fabric.

5. A method for manufacturing a glass plate, characterized in that: The polishing pad according to any one of claims 1 to 4 is pressed against a surface of a glass plate, and polishing is performed by sliding the polishing pad and the glass plate relative to each other while supplying a polishing liquid containing abrasive grains between the glass plate and the polishing pad.

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