Grinding pad and manufacturing method for glass plate

Abstract

To provide: a polishing pad configured so that clogging hardly occurs on a polishing surface which is polishing; and a manufacturing method for a glass plate using the polishing pad.SOLUTION: A polishing pad, which polishes a surface of a glass plate, comprises a plurality of salient row parts. The plurality of salient row parts are arranged at interval in a direction Y that is orthogonal to a direction X in which the salient row parts extend. The salient row parts are constituted of lands extending along the direction X or a plurality of lands arranged discretely along the direction X. A width W of the salient row part is 0.5-5 mm, an interval G between the salient row parts is 0.5-5 mm, and a change rate D obtained by a measurement method P is 10 N / mm or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] 2. Description of the Related Art When manufacturing glass substrates for use in flat panel displays (FPDs) such as liquid crystal displays (LCDs) and organic light-emitting diodes (OLEDs), the surface of the glass substrate obtained by molding molten glass or cutting a block-shaped glass lump is usually polished by a polishing device. In order to polish the surface of such a glass substrate, a polishing liquid containing free abrasive grains and a polishing pad are used. Among them, a technique is known in which grooves or fine holes are provided on the polishing surface of the polishing pad, and the free abrasive grains contained in the polishing liquid are held in the grooves or fine holes on the polishing surface, thereby improving the polishing performance when polishing the surface of the glass substrate.

[0003] Patent document 1 describes an invention relating to a polishing pad having a plurality of first grooves arranged in parallel at a predetermined interval on the polishing surface, 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 in the bottom surfaces of the first grooves and the second grooves. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2013 / 118578 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, when polishing is performed for a long time using a polishing pad and polishing liquid with grooves or micropores (hereinafter also referred to as "groove portion") on the polishing surface, deposits such as abrasive grains or glass products gradually accumulate in the groove portion (hereinafter this phenomenon is also referred to as "clogging"), and the function of retaining the abrasive grains decreases. As a result, the polishing power of the polishing pad decreases, and problems such as a decrease in the polishing accuracy of the glass substrate surface, the occurrence of polishing scratches, and excessive heat due to friction may occur. When clogging occurs in the polishing pad, a process called dressing or sharpening is sometimes carried out to remove deposits from the grooves of the polishing pad. However, if the dressing process is carried out too frequently, the operating rate of the polishing apparatus decreases, and the overall work efficiency decreases.

[0006] In view of the above circumstances, an object of the present invention is to provide a polishing pad which is less likely to clog a polishing surface during polishing. Another object of the present invention is to provide a method for manufacturing a glass substrate using the polishing pad. [Means for solving the problem]

[0007] As a result of intensive research, the present inventors have found that the above problems can be solved by the following configuration.

[0008] [1] 1. A polishing pad for polishing a surface of a glass plate, the polishing pad having a plurality of protruding row portions arranged at intervals in a direction Y perpendicular to a direction X in which the protruding row portions extend, the protruding row portion consisting of a land extending along the direction X or a plurality of lands arranged along the direction X in a discrete manner, the width W of the protruding row portion being 0.5 to 5 mm, the spacing G between the protruding row portions being 0.5 to 5 mm, and a rate of change D obtained by a measurement method P described later being 10 N / mm or less. [2] The polishing pad according to [1], wherein a ratio of the width W to the gap G is 0.2 to 2.0. [3] The polishing pad according to [1] or [2], wherein the height of the protruding row portion is 0.5 to 3.0 mm. [4] The polishing pad according to any one of [1] to [3], which contains a resin or a nonwoven fabric. [5] A method for manufacturing a glass plate, comprising pressing a polishing pad according to any one of [1] to [4] against a surface of a glass plate, and polishing the glass plate by sliding the polishing pad and the glass plate against each other while supplying a polishing liquid containing abrasive grains between the glass plate and the polishing pad. Effect of the Invention

[0009] According to the present invention, there is provided a polishing pad which is less likely to cause clogging on the polishing surface during polishing, and a method for manufacturing a glass substrate using the polishing pad. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing an example of the configuration of a polishing pad according to a first embodiment. [Diagram 2] 2 is a schematic diagram of an apparatus for measuring the rate of change D of a polishing pad by a measurement method P. FIG. [Diagram 3] FIG. [Figure 4] FIG. 4 is an enlarged view of the lower end portion of the pressing jig. [Diagram 5] 11 is a diagram showing the positional relationship between a pressing jig and a protruding row portion of the polishing pad. FIG. [Figure 6] 1 is a graph showing the relationship between the measurement result by measurement method P and the rate of change D. [Figure 7] 6 is a schematic diagram showing an example of the configuration of a polishing pad according to a second embodiment. FIG. [Figure 8] 10 is a schematic diagram showing another example of the configuration of the polishing pad according to the second embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described below with reference to the 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. In addition, the scale of the components shown in each drawing has been appropriately changed from the actual scale in order to make the explanation easier.

[0012] In this specification, a numerical range expressed using "~" means a range including the numerical values ​​described before and after "~" as the lower and upper limits. In the numerical ranges described in stages in this specification, the upper or lower limit described in a certain numerical range may be replaced with the upper or lower limit of another numerical range described in stages. In addition, in the numerical ranges described in this specification, the upper or lower limit described in a certain numerical range may be replaced with a value shown in the examples.

[0013] [Polishing pad] The polishing pad of the present invention is a polishing pad for polishing the surface of a glass plate, the polishing pad having a plurality of convex row portions arranged at intervals in a direction Y perpendicular to the direction X in which the convex row portions extend, the convex row portions consisting of a land extending along the direction X or a plurality of lands arranged discretely from one another along the direction X, the width W of the convex row portions being 0.5 to 5 mm, the spacing G between the convex row portions being 0.5 to 5 mm, and the rate of change D obtained by measurement method P described below being 10 N / mm or less.

[0014] Conventionally, for polishing pads with grooves on the polishing surface for the purpose of improving polishing performance by retaining abrasive grains, wear or damage to the polishing surface due to a reduction in contact area was expected, and therefore materials with relatively high rigidity, strength, etc. were selected as materials for the polishing pad. On the other hand, no attention has been paid to the relationship between the above-mentioned clogging problem in polishing pads with grooves on the polishing surface and the rigidity, etc. of the polishing pad's constituent material. In contrast, in the polishing pad of the present invention, the width W of the convex row portion and the spacing G between the convex row portions are each within a specified range, and the rate of change D is below a specified value, thereby preventing clogging in the groove portions of the polishing surface. Although the details of why the polishing pad according to the present invention has the above-mentioned effect are unclear, it is presumed as follows. As is clear from the measurement method P described below, the above-mentioned change rate D indicates the relationship between the force applied to the polishing pad, particularly the convex row portion, and the amount of movement thereof, and the smaller the change rate D, the more likely the convex row portion is to be made of a material that moves with less force. Then, during polishing of an object such as a glass substrate using the polishing pad according to the present invention, the convex row portion that comes into contact with the object on the polishing surface is largely deflected because the change rate D is relatively small. As a result, it is presumed that the exchange of abrasive grains is promoted at the top of the land that comes into contact with the glass plate during polishing, thereby suppressing the occurrence of clogging. As described above, the polishing pad of the present invention can suppress the occurrence of clogging, thereby stabilizing the polishing force, suppressing polishing scratches, and eliminating the need for dressing work, thereby significantly improving the productivity of the objects to be polished.

[0015] Hereinafter, preferred embodiments of the polishing pad according to the present invention will be described with reference to the drawings.

[0016] [First embodiment] FIG. 1 is a schematic diagram showing an example of the configuration of a polishing pad according to a first embodiment of the present invention. 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).

[0017] 1(a), a polishing pad 10 according to this embodiment has a plurality of protruding row portions 12. Each protruding row portion 12 is made up of a land 14 extending along direction X (the direction indicated by the arrow X in the figure). The plurality of protruding row portions 12 are arranged at intervals in direction Y (the direction indicated by the arrow Y in the figure) perpendicular to direction X. 1(a) and (b), a groove 16 extending in the direction X is formed between two adjacent protruding row portions 12. In other words, the protruding row portions 12 and the grooves 16 are arranged alternately along the direction Y.

[0018] The protruding row portion 12 (land 14) extends from a base end 12B to a tip end 12A along a direction Z (indicated by an arrow Z in the drawing) that indicates the thickness direction of the polishing pad 10. The tip end 12A of the protruding row portion 12 comes into contact with the surface of the glass substrate and polishes the surface of the glass substrate. Thus, the polishing pad 10 according to this embodiment has a polishing surface having a striped pattern in which a plurality of protruding row portions 12 are arranged side by side.

[0019] 1(a) in plan view, the outer periphery of the polishing surface formed by the plurality of protruding row portions 12 is rectangular, but the shape of the polishing surface of the polishing pad according to this embodiment is not limited to a rectangular shape. The outer periphery of the polishing surface of the polishing pad may be a circle, an ellipse, or a polygon other than a rectangle.

[0020] In this embodiment, the width W of the protruding row portion 12 is 0.5 to 5 mm. The width W of the protruding row portion 12 means the distance from one end to the other end of the protruding row portion 12 in the direction Y when the polishing pad 10 is viewed in a plan view. In addition, it is preferable that the widths of the multiple protruding row portions are approximately uniform. The width W of the protruding row portion 12 is preferably 0.5 to 2.5 mm, and more preferably 0.5 to 2.0 mm, in that clogging prevention performance and polishing performance are superior.

[0021] The width W of the convex row portion 12 is determined as an average value by measuring the width in the direction Y at the tip 12A of the convex row portion 12 at 10 or more positions arbitrarily selected along the direction X and taking the arithmetic average of the obtained measurements. Similarly, the spacing G between the convex row portions 12 can be determined by arbitrarily selecting 10 or more positions along the direction X for two adjacent convex row portions 12 that are separated by a groove 16, measuring the distance between two opposing sides at the tips 12A of the two convex row portions 12 at the selected positions along the direction X, and then arithmetically averaging the obtained measurements. In this manner, the width W of the protruding row 12 and the spacing G between the protruding rows 12 are both determined based on distances measured on the polished surface. The height H of the convex row portion 12 is determined as an average value by cutting the convex row portion 12 along a YZ plane perpendicular to the direction X of the convex row portion 12 at 10 or more positions arbitrarily selected along the direction X of the convex row portion 12, observing the cut surface using a scanning electron microscope (SEM), measuring the height of each convex row portion from the obtained observation image, and taking the arithmetic average of the obtained measured values.

[0022] In this embodiment, the spacing G between the adjacent protruding row portions 12 is 0.5 to 5 mm. The spacing G between the adjacent protruding row portions 12 means the distance between two adjacent protruding row portions 12 in direction Y when the polishing pad 10 is viewed in plan, and is synonymous with the width of the grooves 16 in direction Y. The interval G between the adjacent protruding rows 12 is preferably 0.5 to 2.5 mm, and more preferably 0.5 to 2.0 mm, in terms of better clogging prevention performance and polishing performance. Although there are multiple intervals between the adjacent protruding rows, they are preferably approximately constant.

[0023] The ratio (W / G) of the width W of the convex row portion 12 to the spacing G between the convex row portions 12 is, for example, 0.2 to 2.0, and is preferably 0.2 to 1.5, and more preferably 0.5 to 1.5, in that it is possible to expand the polishing area while ensuring the dischargeability of the polishing liquid containing abrasive grains.

[0024] The height H of the protruding row portion 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. The ratio (H / W) of the height H of the row of protrusions 12 to the width W of the row of protrusions 12 is preferably 1.0 to 2.5, and more preferably 1.5 to 2.0.

[0025] The cross-sectional shape of the convex row portion when cut along a plane perpendicular to the direction X may be a rectangle as shown in Fig. 1, a trapezoid in which the base end width is wider than the tip end width, or a trapezoid in which the base end width is narrower than the tip end width. The outer periphery of the cross-sectional shape may be curved except for the base end and the tip end. The cross-sectional shape is preferably a rectangle or a trapezoid in which the base end width is wider than the tip end width, and more preferably a rectangle.

[0026] <Rate of change D> The polishing pad according to this embodiment has a rate of change D of 10 N / mm or less, which is obtained by the following measurement method P. Measurement method P: Among the multiple protruding row portions, a protruding row portion located at one end in direction Y is selected as the measurement target, and a pressing tool is abutted against an area of ​​0.6±0.1 mm from the tip of the selected protruding row portion toward the base end of the end face in direction Y of the selected protruding row portion that is not facing the other protruding row portions, and pressed along direction Y at a speed of 0.5 mm / min to measure the amount of movement of the pressing tool (unit: mm) and the load acting on the pressing tool (unit: N). A graph is created with the amount of movement on the horizontal axis and the load on the vertical axis. An approximation line of the graph is derived by the least squares method in the range from when the pressing tool abuts against the area until it moves a distance half the width W of the selected protruding row portion, and the slope of the derived approximation line is taken as the rate of change D (N / mm).

[0027] The rate of change D of the polishing pad is preferably 8 N / mm or less, and more preferably 6 N / mm or less, in that the clogging prevention performance is more excellent. The rate of change D of the polishing pad is, for example, 0.5 N / mm or more, and is preferably 1 N / mm or more in that the durability of the polishing pad itself is superior.

[0028] Below, a specific example of a pressing jig used in measurement method P will be described, and then measurement method P will be described in more detail.

[0029] (Push-in jig) FIG. 2 is a schematic diagram of an apparatus for measuring the rate of change D of a polishing pad by the measurement method P. The pressing jig 110 is a component of the measuring device 100 shown in Fig. 2, and is used when measuring the rate of change D of the polishing pad by the measuring method P. More specifically, when measuring the rate of change D of the polishing pad by the measuring device 100, the pressing jig 110 presses, at a constant speed, the convex row portion 12s located at one end in the direction Y among the multiple convex row portions of the polishing pad sample S. In the pressing jig 110 shown in the figure, the pressing direction (hereinafter simply referred to as the pressing direction) is a downward direction in the vertical direction, and is a downward direction in the direction Y on the paper.

[0030] An example of a suitable configuration of the pressing jig 110 will now be described. Fig. 3 is a perspective view of the pressing jig 110. Fig. 4 is an enlarged view of the lower end portion of the pressing jig 110. Fig. 5 is a diagram showing the positional relationship between the pressing jig 110 and the protruding row portion of the polishing pad. The pressing jig 110 is made of a material having sufficient hardness to press the convex row portion of the polishing pad, and is constituted by, for example, a metal member made of a metal material having a Young's modulus of 170 GPa or more. The pressing jig 110 is substantially L-shaped in side view, and has a base portion 112 and a pressing portion 114 as shown in FIG.

[0031] The base portion 112 is a portion provided for connecting the pressing jig 110 to a driving device, and more specifically, as shown in Figs. 2 and 3, the lower end of the connecting shaft 120 extending downward from the driving device in the vertical direction Y is fixed to a predetermined position of the base portion 112. The fixing position of the connecting shaft 120 in the base portion 112 is not particularly limited, but it is preferable that the connecting shaft 120 is fixed to the center of the base portion 112 in a plan view. The base portion 112 has a rectangular shape in a plan view and has a sufficient thickness as the base portion 112. The planar size and thickness of the base portion 112 are not particularly limited, but for example, the planar size may be about 25 mm on one side and about 5 mm in thickness.

[0032] The pressing portion 114 is a columnar portion protruding from the base portion 112 and has, for example, a substantially rectangular parallelepiped shape, and when the pressing jig 110 is in use, it protrudes downward in direction Y as shown in Fig. 2. The pressing portion 114 extends along direction X (a direction penetrating the paper surface in Fig. 2) and extends from one end to the other end of the base portion 112 in direction X. In other words, in direction X, the pressing portion 114 has the same length as the base portion 112. In addition, the length of the pressing portion 114 in direction X is designed to be sufficiently longer than the length in direction X of the convex row portion of the polishing pad sample.

[0033] In addition, in direction Z (the left-right direction on the paper in FIG. 2), the width of tip end 114t of push-in portion 114 is shorter than the width of base portion 112, and specifically, is about half the width of base portion 112. In other words, in direction Z, one end face 114a of push-in portion 114 and one end face 112a of base portion 112 are continuously on the same plane, while the other end face 114b of push-in portion 114 is located at a position set back from the other end face 112b of base portion 112.

[0034] Furthermore, as shown in Figs. 3 and 4, a rectangular cutout 116 is provided at a corner located on the other end face 114b side of the tip 114t (lower end when the pressing jig 110 is used) of the pressing part 114. In other words, a step is formed on the tip side of the other end face 114b of the pressing part 114, and the cutout 116 is formed by this step. The size of this cutout 116 is about 0.6 mm from the other end face 114b in the direction Z, and about 3 mm from the tip of the pressing part 114 in the direction Y. Also, as shown in Figs. 3 and 4, the corner between the other end face 114b of the pressing part 114 and the cutout 116, and the corner between the end face of the cutout 116 in the direction Y and the end face in the direction Z are not chamfered and are bent at approximately a right angle. The notch 116 is continuous in the X direction from one end to the other end of the push-in portion 114.

[0035] (Measurement method P) A method P for measuring the rate of change D of a polishing pad will be described below by taking an example of the operation of the pressing jig 110 configured as above as a representative example. When measuring the rate of change D of the polishing pad by the measurement method P using the pressing jig 110, a sample of the polishing pad (hereinafter, sample S) is attached to the side of a holding jig 122 as shown in Fig. 2. The holding jig 122 is a metal block body that is substantially rectangular in shape and has a rectangular side (hereinafter, holding surface 124). The holding jig 122 is used in a state where it is attached to a mounting hardware fixed to a workbench by a fastener such as a bolt, and while the holding jig 122 is in use, the holding surface 124 is perpendicular (upright) to the direction Y (horizontal direction) as shown in Fig. 2.

[0036] Sample S is a polishing pad to be measured, and has a square shape with each side measuring about 15 mm in plan view. In sample S, like polishing pad 10 shown in Fig. 1, a protruding row portion 12 extends in direction Z, and a plurality of protruding row portions 12 are arranged at regular intervals on the surface of sample S in direction Y perpendicular to direction Z in which protruding row portion 12 extends. The sample S may be a pad fragment cut out from the polishing pad to be measured.

[0037] The sample S is held by the holding jig 122 by being attached to the holding surface 124 with an adhesive or the like. At this time, the sample S is held by the holding jig 122 in a state in which the direction in which the multiple convex row portions 12 are lined up (direction Y), i.e., a direction on the surface of the sample S perpendicular to the extension direction of the convex row portions 12, is aligned vertically, as shown in FIG.

[0038] After the sample S is fixed to the holding jig 122, the pressing jig 110 is set in a position directly above the sample S as shown in Fig. 2. Thereafter, a drive device connected to the pressing jig 110 is operated, thereby lowering the pressing jig 110, and eventually the tip portion (lower end portion) of the pressing portion 114 provided on the pressing jig 110 comes into contact with the sample S. At this time, a notch portion 116 formed in the tip corner portion of the pressing portion 114 gets caught on a free end portion (tip portion) of a convex row portion 12s arranged at one end in the direction Y among the multiple convex row portions 12 provided on the sample S, and engages with the convex row portion 12s.

[0039] 4, a notch 116 provided on an end surface 114b of the pressing part 114 of the pressing jig 110 facing the holding jig 122 abuts against the free end (tip) of the convex row portion 12s, and an end surface of the notch 116 in the direction Y abuts against an upper surface of the convex row portion 12s (an end surface in the direction Y that does not face other convex row portions 12). At this time, the region of the upper surface of the convex row portion 12s that abuts against the notch 116 is a region of 0.6±0.1 mm from the tip of the convex row portion 12s toward the base end. Also, as shown in FIG. 5, the pressing part 114 abuts against the convex row portion 12s from one end to the other end of the sample S in the direction X of the pressing jig 110, in other words, abuts against the entire range of the convex row portion 12s in the direction X. 5 is a view of the row of protruding portions 12s seen from above, and in this figure, the pushing portion 114 that abuts against the row of protruding portions 12s is shown by a dashed line. As shown in the figure, the pushing portion 114 abuts against an area 0.6 mm from the tip of the row of protruding portions 12s toward the base end, and a load is applied downward (direction Y from the front to the back of the page).

[0040] Thereafter, the pressing jig 110 continues to descend at a constant speed by the driving device. As a result, the pressing jig 110 continues to press the convex row portion 12s downward along the direction Y while keeping the notch portion 116 of the pressing portion 114 engaged with the convex row portion 12s of the sample S. At this time, the load (pressing load) acting on the pressing jig 110 is successively measured by a load cell built into the driving device. Also, during the descent of the pressing jig 110, its amount of movement, more specifically, the amount of movement of the connecting shaft 120 described above, is successively measured by a sensor built into the driving device.

[0041] FIG. 6 shows an example of a graph showing the relationship between the measurement results by measurement method P and the rate of change D. In the graph shown in FIG. 6, the horizontal axis shows the amount of movement M (unit: mm) of the pressing jig 110 measured by the above method, and the vertical axis shows the load L (unit: N) acting on the pressing jig 110. FIG. 6 shows a curve C by a solid line indicating the relationship between the measured amount of movement M of the pressing jig 110 and the load L acting on the pressing jig 110. Also, in FIG. 6, "M0" indicates the position of the pressing jig 110 when the pressing jig 110 moves and the end face of the uppermost convex row portion 12s abuts against the step surface of the pressing portion 114, and "M H " indicates the position where the amount of movement from M0 is half the distance of the width W of the protruding row portion 12s. H For the curve C in the range from 0.01 to 0.25, an approximation line A is derived by the least squares method (see FIG. 6), and the gradient of the derived approximation line A is taken as the rate of change D (N / mm).

[0042] Note that the measurement method using the pressing jig 110 shown in Figures 2 to 5 is merely one example of measurement method P, and the rate of change D of the polishing pad can be measured as measurement method P as long as the convex row portion that contacts the pressing jig is the convex row portion that is located at one end in the Y direction among the multiple convex row portions, the range of contact with the pressing jig is an area of ​​0.6 ± 0.1 mm from the tip to the base end of the end face in the direction Y that does not face other convex row portions of the above convex row portion, the speed at which the pressing jig moves is constant before and after it contacts the above convex row portion, and the measurement method can measure the amount of movement while the pressing jig moves and the load acting on the pressing jig.

[0043] The material constituting the polishing pad according to this embodiment can be appropriately selected from known polishing pad materials according to the target change rate D. Examples of the material constituting the polishing pad include nonwoven fabric and resin such as polyurethane. 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 nonwoven fabric. The polishing pad according to this embodiment may be composed of a single layer or a laminate having multiple layers, as long as the rate of change D is within a predetermined range. The materials of the layers constituting the laminate may be the same or different, and may be appropriately selected from the above materials.

[0044] The material constituting the polishing pad is preferably a material having an A hardness of 10 to 80 degrees, more preferably a material having an A hardness of 20 to 65 degrees. The A hardness can be measured using a rubber hardness tester according to a method in accordance with JIS K 6253. The material constituting the polishing pad preferably has a Young's modulus based on the ASTM material testing standard of 0.1 to 20 MPa, and more preferably 0.2 to 10 MPa.

[0045] Second Embodiment FIG. 7 shows an example of the configuration of a polishing pad according to a second embodiment of the present invention. FIG. 7 is a plan view of a polishing pad 20 according to the second embodiment. 7, the polishing pad 20 according to this embodiment has a plurality of protruding row portions 22. Each protruding row portion 22 is made up of a plurality of lands 24 that are spaced apart from one another and arranged along direction X. The plurality of protruding row portions 22 are also arranged at intervals in direction Y that is perpendicular to direction X.

[0046] 7, a first groove 26 extending in the direction X is formed between two adjacent protruding row portions 22. That is, the protruding row portions 22 and the first grooves 26 are arranged alternately along the direction Y. In addition, a second groove 28 is formed between two adjacent lands 24, intersecting with the first groove 26 at an angle of 45°. That is, the lands 24 and the second grooves 28 are arranged alternately along the direction X.

[0047] The protruding row portion 22 and the land 24 extend from the base end to the tip end along direction Z, which indicates the thickness direction of the polishing pad 20. The tip end of this protruding row portion 22 comes into contact with the surface of the glass substrate and polishes the surface of the glass substrate. Thus, the polishing pad 20 shown in FIG. 7 has a polishing surface having a diagonal lattice pattern in which a plurality of lands 24 are arranged side by side in both the direction X and a direction intersecting the direction X.

[0048] FIG. 8 shows another example of the configuration of the polishing pad according to the second embodiment of the present invention. FIG. 8 is a plan view of a polishing pad 30 according to the second embodiment. 8, the polishing pad 30 according to this embodiment has a plurality of protruding row portions 32. Each protruding row portion 32 is made up of a plurality of lands 34 that are spaced apart from one another and arranged along direction X. The plurality of protruding row portions 32 are also arranged at intervals in direction Y that is perpendicular to direction X.

[0049] 8, a first groove 36 extending in the direction X is formed between two adjacent protruding row portions 32. That is, the protruding row portions 32 and the first grooves 36 are arranged alternately along the direction Y. In addition, a second groove 38 perpendicular to the first groove 36 is formed between two adjacent lands 34. That is, the lands 34 and the second grooves 38 are arranged alternately along the direction X.

[0050] The protruding row portion 32 and the land 34 extend from the base end to the tip end along direction Z, which indicates the thickness direction of the polishing pad 30. The tip end of the protruding row portion 32 comes into contact with the surface of the glass substrate and polishes the surface of the glass substrate. Thus, the polishing pad 30 shown in FIG. 8 has a polishing surface having a grid pattern in which a plurality of lands 34 are arranged in each of the X direction and the Y direction.

[0051] In this embodiment, when the polishing pad is viewed in plan, the width W of the land constituting the protruding row portion extending along the direction X is L The diameter is, for example, 0.5 to 5.0 mm, and is preferably 0.5 to 3.0 mm, and more preferably 0.5 to 2.5 mm, in that it provides better clogging prevention performance and polishing performance. The width of the land W L As shown in the figure, “distance between two opposing sides that form a boundary with the second groove” among the four sides that form the periphery of the land.

[0052] In this embodiment, when the polishing pad is viewed in plan, the interval G between two adjacent lands in the protruding row portion extending along the direction X is L 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, in that clogging prevention performance and polishing performance are superior. The distance between two adjacent lands is G L As shown in the figure, means the distance between the sides of one land and the other land that face each other across the second groove.

[0053] In this embodiment, the distance G between the two adjacent lands is L Width of land W L Ratio (W L / G L ) is, for example, 0.2 to 4.0, and is preferably 0.5 to 2.0 from the viewpoint of increasing the polishing area while ensuring the dischargeability of the polishing liquid containing abrasive grains.

[0054] For the polishing pad of the second embodiment, the shape and arrangement of the convex row portions other than those described above, such as the width W of the convex row portions and the spacing G between the convex row portions, the rate of change D, and the constituent materials, etc., are the same as those of the polishing pad of the first embodiment, including their preferred aspects.

[0055] Hereinafter, a method for producing and applications of the polishing pad according to the present invention including the first and second embodiments will be described.

[0056] [Polishing pad manufacturing method] The polishing pad according to the present invention can be manufactured by a known method. For example, a plurality of grooves extending in one direction are formed at intervals on the surface of a sheet material made of the above-mentioned polishing pad constituent material by cutting, thereby forming a convex row portion consisting of lands extending in the one direction. Also, 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 row portion consisting of a plurality of lands extending in the first direction and arranged along the first direction while being separated from each other.

[0057] In the above-mentioned process of forming the protruding row portion, the width W of the protruding row portion and the interval G between the protruding row portions can be adjusted by changing the width and pitch of each groove. In addition, by changing the width and pitch of each groove and selecting the material of the polishing pad, the rate of change D of the polishing pad can be adjusted.

[0058] [Glass sheet manufacturing method] The polishing pad according to the present invention can be used in a method for producing a glass plate, in which the surface of the glass plate is polished using the polishing pad. An example of a method for manufacturing a glass plate according to the present invention is a method in which the polishing pad according to the present invention is pressed against the surface of a glass plate, and the polishing pad and the glass plate are polished by sliding them against each other while a polishing liquid containing abrasive grains is supplied between the glass plate and the polishing pad. By polishing the surface of a glass plate with the polishing pad of the present invention, minute irregularities and waviness can be removed, and a glass plate that satisfies the flatness required for a glass plate for, for example, an FPD can be produced.

[0059] Examples of the glass plate to be polished include glass plates used in FPDs such as plasma displays, LCDs, and OLEDs. The size and shape of the glass plate can be appropriately selected depending on the application. The glass plate has, for example, a rectangular shape, and its size is, for example, 100 to 3000 mm on a side. The thickness of the glass plate varies depending on the application, but for glass plates for FPDs, the thickness is preferably 0.2 to 0.7 mm, and more preferably 0.4 to 0.5 mm.

[0060] The polishing liquid may be, for example, a fluid containing abrasive grains and a dispersion medium for the abrasive grains. The abrasive grains are preferably colloidal silica or cerium oxide. 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 the 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. Examples of the dispersion medium for the abrasive grains include water and organic solvents, with water being preferred. The content of the abrasive grains in the polishing liquid is, for example, 5 to 40 mass %.

[0061] Examples of polishing devices used for polishing glass plates include devices equipped with a work platen that holds the underside of the glass plate via an adsorption sheet, a polishing platen to which a polishing pad is attached, a rotating shaft that rotates the polishing platen, and a polishing liquid supply unit that supplies a polishing liquid to the polishing pad. The rotating shaft is rotated about its own axis and revolved about its own revolution axis by the driving means. The polishing table rotates and revolves in accordance with the rotation and revolution of the rotating shaft. The rotation of the polishing table may be only revolution or only rotation. Revolution refers to the rotational motion of the polishing table revolving around the revolution axis along a circular orbit. The polishing liquid supply unit supplies a polishing liquid between the polishing surface of the polishing pad and the surface of the glass plate.

[0062] When the polishing device is operated, the polishing surface of the polishing pad is pressed against the surface of the glass plate to be polished, a polishing liquid is supplied between the polishing surface of the polishing pad and the surface of the glass plate, and the polishing pad and the glass plate slide against each other due to the rotation and revolution of the polishing pad, and the polishing force of the abrasive grains is also added, polishing the surface of the glass plate.

[0063] The glass plate manufacturing method according to the present invention can also be applied to glass plate polishing methods and polishing devices other than those described above. The direction in which the polishing pad and the glass plate slide against each other is not limited to the rotational direction, but may be a reciprocating direction. In addition, the polishing device may have multiple polishing pads. The polishing apparatus may be a batch type polishing apparatus, or a continuous type polishing apparatus that polishes the surface of the glass plate being transported.

[0064] In the method for producing a glass plate, steps other than the polishing step include, for example, a forming step of forming molten glass into a plate shape by a method such as a float method, and a cutting step of cutting the plate-shaped glass into glass plates of a predetermined size. EXAMPLES

[0065] The present invention will be specifically described below with reference to 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.

[0066] (Example 1) A laminate was prepared consisting of a 2.1 mm thick base layer made of material 1 and a 0.3 mm thick soft polyurethane layer. The size of the laminate was 15 mm long and 15 mm wide, with a total thickness of 2.4 mm. Material 1 was a nonwoven fabric, as shown in Table 2 below. A groove with a width of 1 mm and a depth of 1.6 mm was formed by cutting on the surface of the laminate facing the soft polyurethane layer, extending linearly in a first direction. By forming a plurality of such grooves at a pitch of 4 mm, a polishing pad having a polishing surface with a striped pattern in which a plurality of convex rows made of lands extending along the X direction are arranged at intervals in the Y direction, as shown in Figure 1, was produced. The width W of the protruding row portion, the distance G between the protruding row portions, and the height H of the protruding row portion on the polishing surface of the produced polishing pad are shown in Table 1 below.

[0067] (Examples 2 to 7) Polishing pads having a polishing surface with a striped pattern were prepared according to the method described in Example 1, except that a substrate layer made of the material shown in Table 1 was used as the substrate layer constituting the laminate, and that the shape and pitch of the grooves formed by cutting were changed so as to form a polishing surface having the width W and spacing G of the convex row portion shown in Table 1.

[0068] (Example 8) A polishing pad having a flat polishing surface was prepared according to the method described in Example 1, except that the cutting process in Example 1 was not performed and no grooves were formed.

[0069] (Example 9) A laminate was prepared consisting of a nonwoven fabric base layer having a thickness of 2.1 mm and a soft polyurethane layer having a thickness of 0.3 mm. The size of the laminate was 15 mm long and 15 mm wide, with a total thickness of 2.4 mm. On the surface of the laminate on the side of the soft polyurethane layer, a plurality of first grooves extending linearly in a first direction and a plurality of second grooves extending linearly in a second direction at an intersection angle of 45° with the first direction were provided by cutting. Both the first groove and the second groove had a groove width of 1.5 mm, a groove depth of 1.6 mm, and a groove pitch of 3 mm. As a result, a polishing pad having a diagonal lattice-like polishing surface was produced, in which a plurality of convex row portions consisting of a plurality of lands arranged discretely along the X direction were arranged at intervals in the Y direction, as shown in FIG. 7.

[0070] (Measurement of rate of change D) The rate of change D of the polishing pad of each example was measured using the pressing jig shown in Figures 2 to 5 according to the above-mentioned measuring method P. The measurement results are shown in Table 1.

[0071] (Polishing test) The above polishing pad was fixed to the lower platen of a batch type single-sided polishing machine with double-sided adhesive tape. In addition, an alkali-free glass plate with a thickness, length and width of 0.5 mm x 300 mm x 300 mm was attached to the film frame to which a self-adhesive resin sheet was attached. In this state, a polishing liquid containing cerium oxide abrasive grains with an average grain size of 1 μm was supplied between the glass plate and the polishing pad, and the surface pressure was 100 g / cm. 2 The polishing was carried out for a total of 12 hours. After the polishing test, the surface of the polishing pad was observed visually and under a microscope, and the clogging of the polishing pad was evaluated based on the observation results of the polishing pad surface and on the following evaluation criteria.

[0072] (Clogging evaluation criteria) ◯: Almost no clogging occurred. ×: Significant clogging occurred.

[0073] Table 1 shows the polishing surface pattern, material, shape of the convex row portion, and measured value of the change rate D of the polishing pad produced in each example, as well as the evaluation results of clogging of the polishing pad after the polishing test. The evaluation results of clogging of the polishing pad are shown for Examples 1 to 8. In the table, the column "polished surface pattern" indicates the pattern shape of the polished surface formed by the lands, and "no pattern" means that the polished surface is a flat surface without any uneven structure.

[0074] Table 2 shows the types, A-hardness, density and Young's modulus of materials 1 to 3 constituting each polishing pad. The A-hardness of each material was measured using a rubber hardness tester according to JIS K 6253. The density of each material was measured using a precision electronic balance for a sample cut into a unit area (10 cm x 10 cm).

[0075] [Table 1]

[0076] [Table 2]

[0077] As shown in Table 1 above, in the polishing pads of Examples 2 and 4, in which 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, clogging did not occur on the polishing surface, and the clogging suppression performance was excellent. In contrast, in the polishing pads of Examples 1, 3, and 5 to 8, in which the rate of change D is more than 10 N / mm, significant clogging occurred on the polishing surface, and the clogging suppression performance was insufficient. In addition, it is presumed that the polishing pad of Example 9, in which 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, also does not cause clogging on the polishing surface, and has excellent clogging suppression performance. [Explanation of symbols]

[0078] 10,20,30 Polishing Pad 12,12s,22,32 Convex row part 12A Tip 12B Proximal end 14,24,34 Land 16 groove 26,36 First Groove 28,38 Second Groove 100 Measuring Equipment 110 Pressing jig 112 Base 114 Push-in section 116 Cutout 120 Connecting shaft 122 Holding fixture 124 Holding surface S Sample

Claims

1. A polishing pad for polishing a surface of a glass plate, the polishing pad having a plurality of raised rows; The plurality of protruding row portions are arranged at intervals in a direction Y perpendicular to a direction X in which the protruding row portions extend, The protruding row portion is composed of a land extending along the direction X or a plurality of lands spaced apart from one another and arranged along the direction X, The width W of the convex row portion is 0.5 to 5 mm, The interval G between the protruding rows is 0.5 to 5 mm; A polishing pad characterized in that the rate of change D obtained by the following measurement method P is 10 N / mm or less. Measurement method P: Of the multiple protruding row portions, a protruding row portion located at one end in direction Y is selected as the measurement target, and a pressing tool is abutted against an area of ​​0.6±0.1 mm from the tip of the selected protruding row portion toward the base end of the end face in direction Y of the selected protruding row portion that does not face the other protruding row portions, and pressed along direction Y at a speed of 0.5 mm / min, measuring the amount of movement of the pressing tool (unit: mm) and the load acting on the pressing tool (unit: N). A graph is created with the amount of movement on the horizontal axis and the load on the vertical axis. An approximation line of the graph in the range from when the pushing tool contacts the region to when it moves a distance of half the width W is derived by the least squares method, and the slope of the derived approximation line is the rate of change D (N / mm).

2. 2. The polishing pad of claim 1, wherein the ratio of the width W to the spacing G is between 0.2 and 2.

0.

3. 2. The polishing pad according to claim 1, wherein the height of the raised row portion is 0.5 to 3.0 mm.

4. The polishing pad of claim 1 comprising a resin or a nonwoven fabric.

5. A method for manufacturing a glass plate, comprising pressing the polishing pad according to any one of claims 1 to 4 against a surface of a glass plate, and polishing the glass plate by sliding the polishing pad and the glass plate against each other while supplying a polishing liquid containing abrasive grains between the glass plate and the polishing pad.

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