JP2021030325A - Polishing material - Google Patents

Abstract

To provide a manufacturing method for a polishing material that can eliminate the necessity of a step of making a base material adhere to a support body by laminating a polishing layer directly on a surface side of the support body, is superior in manufacturing efficiency and can prevent deterioration in manufacturing yield due to the adhesion step and peeling of the polishing material when using the material.SOLUTION: A manufacturing method for a polishing material according to the present invention comprises a step of forming a tabular support body and a step of forming a polishing layer including abrasive grain and a binder on a surface side of the support body. The step of forming the support body includes: a step of mixing supercritical fluid with molten resin; a step of injecting the mixed molten resin into a mold having a recessed part that can form the support body; and a step of widening the recessed part of the mold filled with the resin in a plate thickness direction of the support body to be formed.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing an abrasive and an abrasive.

For example, a fixed abrasive grain abrasive is generally used for processing a glass substrate used in an electronic device such as a hard disk. As such an abrasive, those provided with a base material and a polishing layer laminated on the surface side of the base material and containing abrasive grains and a binder are known (see, for example, Re-Table 2017/119342).

In the above-mentioned abrasive material, a thermosetting resin is used as a binder for the polishing layer, and the polishing layer is formed by heat curing. Therefore, heat resistance is required for the base material, and a relatively hard resin is used. On the other hand, the abrasive is required to have impact resistance and flexibility to follow the object to be ground. If the base material is thickened to ensure the impact resistance of the abrasive material, the requirement for flexibility cannot be satisfied. Therefore, the conventional abrasive material is further provided with a support fixed to the base material with an adhesive or the like. The support ensures impact resistance and flexibility.

As described above, the conventional abrasive requires a step of attaching the base material and the support. Further, with the conventional abrasive, the manufacturing yield may decrease due to the misalignment at the time of sticking, and further, the sticking portion between the base material and the support may be peeled off at the time of use. Therefore, there is a need for a method for producing an abrasive that can omit the pasting step, that is, a method for producing an abrasive that can directly laminate an abrasive layer on the surface side of the support.

Re-table 2017/11934

The present invention has been made in view of such inconveniences. By directly laminating the polishing layer on the surface side of the support, the step of attaching the base material and the support is not required, the production efficiency is excellent, and the application is performed. An object of the present invention is to provide a method for producing an abrasive and a method for producing the abrasive, which can prevent a decrease in the production yield due to the process and peeling when the abrasive is used.

The method for producing an abrasive material of the present invention includes a step of forming a plate-shaped support and a step of forming a polishing layer containing abrasive grains and a binder on the surface side of the support, as the support forming step. , A step of kneading the supercritical fluid with the molten resin, a step of filling the molten resin after the mixing step into a molding die having a recess capable of forming the support, and a recess of the molding die after the filling step. Has a step of widening the formed support in the plate thickness direction.

In the method for producing the abrasive, a molten resin kneaded with a supercritical fluid is filled in a molding die, and the molding die is widened in the plate thickness direction. By widening the molding die in the plate thickness direction, the supercritical fluid foams, and a region including pores is formed in the central portion in the thickness direction of the support. Due to the region including the pores of the support, the abrasive material produced by the method for producing the abrasive material can have appropriate impact resistance and flexibility while having heat resistance. Further, in the method for producing the abrasive, the abrasive layer can be directly laminated on the surface side of the support, and it is not necessary to use a base material. Therefore, since the method for manufacturing the abrasive does not require a sticking step between the base material and the support, the manufacturing efficiency is excellent, and it is possible to prevent a decrease in the manufacturing yield and peeling when the abrasive is used due to the sticking step. .. Further, in the abrasive material produced by the method for producing the abrasive material, the porosity on the front surface side and the back surface side of the support is lower than that in the central portion in the thickness direction, so that the front surface and the back surface of the support have irregularities. The number is small, and the polishing layer can be easily laminated on the front surface side and the back surface side can be easily attached to the surface plate of the polishing machine.

It is preferable that the supercritical fluid is nitrogen. Nitrogen, which is a kind of supercritical fluid, is an inert gas and is chemically stable, so that the characteristics of the molten resin can be easily exhibited after solidification.

In the widening step, the surface temperature of the concave portion of the molding die may be lower than the temperature of the molten resin at the center in the plate thickness direction, and the temperature difference may be 50 ° C. or higher and 150 ° C. or lower. By keeping the temperature difference between the surface temperature of the concave portion of the molding mold and the temperature of the molten resin within the above range, the porosity is secured at the central portion in the thickness direction of the support, and the front surface side and the back surface side and the back surface are secured. It is easy to reduce the porosity on the side. Therefore, it is possible to further facilitate the lamination of the polishing layer on the front surface side and the attachment of the back surface side to the surface plate of the polishing machine.

The main component of the molten resin is preferably polycarbonate. By using polycarbonate as the main component of the molten resin in this way, it is possible to impart appropriate impact resistance and flexibility to the support while ensuring the heat resistance required for the support.

The abrasive material of the present invention includes a plate-shaped support and a polishing layer laminated on the surface side of the support and containing abrasive grains and a binder, the support includes pores, and the porosity of the support. However, it becomes maximum at the central portion in the thickness direction and decreases on the front surface side and the back surface side.

Since the support contains pores, the abrasive can have appropriate impact resistance and flexibility while having heat resistance. Further, in the abrasive material, an abrasive layer is laminated on the surface side of the support, and it is not necessary to use a base material. Therefore, since the abrasive does not require a sticking step between the base material and the support in its manufacture, the manufacturing efficiency is excellent, and it is possible to prevent a decrease in the manufacturing yield and peeling when the abrasive is used due to the sticking step. .. Further, in the abrasive, the porosity on the front surface side and the back surface side of the support is lower than that in the central portion in the thickness direction, so that the front surface and the back surface of the support have less unevenness, and the polishing layer is laminated on the front surface side. Also, the back side can be easily attached to the surface plate of the polishing machine.

The support may be a single layer. By forming the support into a single layer in this way, it is possible to improve the effect of suppressing the occurrence of peeling when the abrasive is used.

The arithmetic mean roughness Ra of the surface of the support is preferably 0.1 μm or less. By setting the arithmetic average roughness Ra of the surface of the support to be equal to or less than the upper limit in this way, it is possible to further facilitate the lamination of the polishing layer on the surface side.

The average porosity of the support is preferably 20% by volume or more and 80% by volume or less. By setting the average porosity of the support within the above range, it is possible to reduce the unevenness of the front surface and the back surface of the support while imparting appropriate impact resistance and flexibility to the support. It is possible to easily stack the polishing layer on the surface plate and attach the back surface side to the surface plate of the polishing machine.

Here, the "main component" means a component having the highest content, preferably a component having a content of 50% by mass or more, and more preferably 90% by mass or more. "Porosity" means the percentage of the volume of the pores to the volume of the support including the pores. Further, the "average porosity" is a percentage of the total volume of the pores with respect to the total volume including the pores in the region of the target support. The “central portion in the thickness direction” means a region including the center in the thickness direction of the support, and refers to, for example, a region within 30% of the average thickness of the support from the center in the thickness direction of the support. “Arithmetic mean roughness Ra” means a value measured in accordance with JIS-B-0601: 2001.

As described above, by using the method for producing an abrasive material of the present invention, the abrasive layer can be directly laminated on the surface side of the support. The abrasive material produced by the method for producing the abrasive material and the abrasive material are excellent in production efficiency by directly laminating the abrasive layer on the surface side of the support, eliminating the need for a sticking process between the base material and the support. , It is possible to prevent a decrease in manufacturing yield due to the pasting process and peeling when using an abrasive.

It is a flow chart which shows the manufacturing method of the abrasive material which concerns on one Embodiment of this invention. It is a detailed flow chart of the support forming process of FIG. It is a schematic cross-sectional view which shows the molding die used in the support forming process of FIG. FIG. 3 is a schematic cross-sectional view showing a state in which the molding die of FIG. 3 is widened. It is a schematic partial sectional view of the support formed in the support forming step of FIG. It is a detailed flow chart of the polishing layer forming process of FIG. It is a schematic partial sectional view which shows the abrasive material which concerns on one Embodiment of this invention. It is a schematic plan view of the abrasive material of FIG.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings as appropriate.

[Abrasive manufacturing method]
The method for producing an abrasive shown in FIG. 1 includes a support forming step S1 and a polishing layer forming step S2.

<Support forming process>
In the support forming step S1, a plate-shaped support is formed. As shown in FIG. 2, the method for producing the abrasive material includes a kneading step S11, a filling step S12, and a widening step S13 as the support forming step S1.

(Kneading process)
In the kneading step S11, the supercritical fluid is kneaded with the molten resin.

Examples of the main component of the molten resin include polycarbonate (PC), polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyimide (PI), polyethylene naphthalate (PEN) and the like. Above all, the main component of the molten resin is preferably polycarbonate. By using polycarbonate as the main component of the molten resin in this way, it is possible to impart appropriate impact resistance and flexibility to the support while ensuring the heat resistance required for the support.

In the kneading step S11, the molten resin is set to a temperature at which the molten state can be maintained, that is, a temperature equal to or higher than the melting point of the resin as the main component, for example, 200 ° C. or higher.

A supercritical fluid is a fluid that has both gas and liquid properties above the critical temperature and pressure. Examples of the supercritical fluid include butane, nitrogen, carbon dioxide and the like. Of these, nitrogen is preferable as the supercritical fluid. Nitrogen, which is a kind of supercritical fluid, is an inert gas and is chemically stable, so that the characteristics of the molten resin can be easily exhibited after solidification.

The lower limit of the content of the supercritical fluid with respect to the total volume of the supercritical fluid and the molten resin is preferably 0.1% by volume, more preferably 0.3% by volume. On the other hand, as the upper limit of the content of the supercritical fluid, 1% by volume is preferable, and 0.8% by volume is more preferable. If the content of the supercritical fluid is less than the above lower limit, the support to be formed may lack impact resistance or flexibility. On the contrary, if the content of the supercritical fluid exceeds the upper limit, the strength of the formed support may be insufficient.

The lower limit of the pressurizing pressure during kneading in the kneading step S11 is preferably 40 MPa, more preferably 50 MPa. On the other hand, the upper limit of the pressurizing pressure is preferably 100 MPa, more preferably 80 MPa. If the pressurizing pressure is less than the lower limit, the supercritical fluid may not be sufficiently dissolved in the molten resin, or the properties as a supercritical fluid may not be exhibited. On the contrary, when the pressurizing pressure exceeds the upper limit, the cost of the manufacturing equipment for increasing the pressure may be unnecessarily increased.

(Filling process)
In the filling step S12, the molten resin after the mixing step S11 is filled into a molding mold having a recess in which the support can be formed.

In the filling step S2, for example, the molding die 100 shown in FIG. 3 can be used. The molding die 100 shown in FIG. 3 has a molding die main body 101 and a movable portion 102. A recess 103 is formed between the molding die main body 101 and the movable portion 102. Further, the molding die main body 101 is provided with an injection pipe 104 capable of injecting the molten resin into the recess 103.

The recess 103 is configured so that the support can be formed. Specifically, the plan-view shape of the recess 103 is the shape of the support to be formed.

As shown in FIG. 4, the movable portion 102 is configured so that the recess 103 can be widened in the plate thickness direction of the support to be formed. Specifically, the movable portion 102 can move in the direction of the arrow in FIG. 4 from the state where the height of the recess 103 shown in FIG. 3 (the length in the plate thickness direction) is the minimum.

The height of the recess 103 (D1 in FIG. 4) in a state where the movable portion 102 is moved and the recess 103 is widened is defined as the thickness of the support to be formed.

In the filling step S12, the height of the recess 103 is set to the minimum. The height of the recess 103 (D0 in FIG. 3) when the height of the recess 103 is the minimum is determined so that the support to be formed has a desired porosity. Specifically, as the lower limit of the ratio (D0 / D1) of the minimum height D0 of the recess 103 to the widening height D1 of the recess 103, 0.3 is preferable, and 0.5 is more preferable. On the other hand, the upper limit of D0 / D1 is preferably 0.8, more preferably 0.7. If the D0 / D1 is less than the lower limit, the porosity may become too high and the strength of the support may be insufficient. On the contrary, if the D0 / D1 is less than the lower limit, the porosity may be too low and the formed support may lack impact resistance or flexibility.

Further, the molding die 100 is configured so that the temperature of the portion where the molding die main body 101 and the movable portion 102 are in contact with the recess 103 can be controlled.

In the filling step S12, specifically, the molding die 100 of FIG. 3 is used to fill the recess 103 of the molding die 100 from the injection pipe 104 with the height of the recess 103 being the minimum. At this time, the temperature and pressure of the molten resin are maintained at the temperature and pressure in the kneading step S11.

(Wide widening process)
In the widening step S13, the recess 103 of the molding die 100 after the filling step S12 is widened in the plate thickness direction.

Specifically, in the widening step S13, the movable portion 102 of the molding die 100 is moved and widened so that the height of the recess 103 becomes the thickness of the support to be formed (FIG. 4). By this widening step S13, the supercritical fluid contained in the molten resin is foamed, and as shown in FIG. 5, the support 1 including the pores 10 can be formed. Further, since the molten resin is cooled and solidified from the periphery of the molding die 100, the obtained support 1 has a core region 11 including many pores 10 formed in the central portion in the thickness direction of the support 1 and a surface thereof. The structure is formed on the side and the back surface side and has a solid region 12 having a porosity lower than that of the core region 11.

In the widening step S13, the surface temperature of the recess 103 of the molding die 100 may be set lower than the temperature of the molten resin at the center in the plate thickness direction. By setting the surface temperature of the recess 103 of the molding die 100 lower than the temperature of the molten resin in the central portion in the plate thickness direction in this way, the surface of the support 1 while ensuring the porosity in the central portion in the thickness direction. It is easy to reduce the porosity on the side and back side. Therefore, it is possible to prevent the front surface and the back surface of the formed support 1 from having irregularities due to pores, so that it is possible to easily laminate the polishing layer on the front surface side and attach the back surface side to the surface plate of the polishing machine. ..

The lower limit of the temperature difference between the surface temperature of the recess 103 of the molding die 100 and the temperature of the molten resin in the central portion in the plate thickness direction is preferably 50 ° C., more preferably 70 ° C. On the other hand, as the upper limit of the temperature difference, 150 ° C. is preferable, and 120 ° C. is more preferable. If the temperature difference is less than the above lower limit, the porosity on the front surface side and the back surface side of the support 1 is not sufficiently reduced, the polishing layer is laminated on the front surface side, and the back surface side of the polishing machine on the surface plate. It may not be easy to attach. On the contrary, when the temperature difference exceeds the upper limit, it becomes difficult to set at least either the surface temperature of the recess 103 of the molding die 100 or the temperature of the molten resin at the center in the plate thickness direction to an appropriate temperature. Therefore, if the temperature of the molten resin in the central portion in the plate thickness direction becomes too low, the solid region 12 may become thick and the flexibility of the support 1 may not be sufficiently secured, while the central portion in the plate thickness direction. If the temperature of the molten resin becomes too high, the pores 10 may become coarse and the strength of the support 1 may become insufficient.

Further, it is preferable that the surface temperature of the recess 103 of the molding die 100 is a temperature at which the supercritical fluid does not foam, and the temperature of the molten resin at the center in the plate thickness direction is a temperature at which the supercritical fluid foams. By setting such a temperature, the solid regions 12 on the front surface side and the back surface side of the support 1 can be made into regions that do not substantially contain pores. Therefore, it is possible to further facilitate the lamination of the polishing layer on the front surface side and the attachment of the back surface side to the surface plate of the polishing machine.

The surface temperature of the recess 103 of the molding die 100 and the temperature of the molten resin at the center in the plate thickness direction are appropriately set according to the main components of the molten resin.

For example, when the main component of the molten resin is polycarbonate, the lower limit of the surface temperature of the recess 103 of the molding die 100 is preferably 50 ° C., more preferably 70 ° C. On the other hand, the upper limit of the surface temperature of the recess 103 of the molding die 100 is preferably 140 ° C., more preferably 120 ° C. When the surface temperature of the recess 103 of the molding die 100 is less than the above lower limit, the temperature of the molten resin in the central portion in the plate thickness direction drops sharply, so that the solid region 12 becomes thick and the flexibility of the support is sufficiently ensured. It may not be possible. On the contrary, when the surface temperature of the concave portion 103 of the molding die 100 exceeds the above upper limit, the porosity of the solid region 12 is not sufficiently reduced, the polishing layer is laminated on the front surface side, and the back surface of the polishing machine on the surface plate. It may be difficult to attach the side.

When the main component of the molten resin is polycarbonate, the lower limit of the temperature of the molten resin in the central portion in the plate thickness direction is preferably 160 ° C, more preferably 180 ° C. On the other hand, the upper limit of the temperature of the molten resin in the central portion in the plate thickness direction is preferably 250 ° C., more preferably 220 ° C. If the temperature of the molten resin in the central portion in the plate thickness direction is less than the above lower limit, the porosity of the core region 11 may not be sufficiently increased, and the flexibility of the support 1 may not be sufficiently ensured. On the contrary, when the temperature of the molten resin in the central portion in the plate thickness direction exceeds the upper limit, the pores 10 become coarse, so that the strength of the support 1 may be insufficient.

Although the temperature of the molding die 100 can be set after the filling step S12, it is preferable to set the temperature of the molding die 100 before the filling step S12 from the viewpoint of temperature controllability.

The widening in the plate thickness direction may be performed after a certain period of time after filling the molten resin in the filling step S12. In this way, the temperature profile of the molten resin in the plate thickness direction is determined by the time interval between the filling of the molten resin and the widening in the plate thickness direction, so that the thickness of the solid region 12 of the support 1 to be formed is determined. The porosity of the core region 11 is controlled. Specifically, the time interval is 5 seconds or more and 15 seconds or less.

The widening in the plate thickness direction may be performed at a constant speed, but it is preferable to slow down the speed in the first half of the widening. By slowing down the speed in the first half of widening in this way, it is possible to prevent a large number of pores 10 from being generated and invading the solid region 12 in a state where solidification has not progressed.

The pressure in the recess 103 of the molding die 100 decreases with the widening in the plate thickness direction. The lower the pressure in the recess 103, the larger the diameter of the generated pores 10 tends to be. Therefore, the pressure in the recess 103 is adjusted so as to have a desired pore diameter.

After widening in the plate thickness direction, the molten resin is cooled to form the support 1. This cooling method is not particularly limited, but may be, for example, natural cooling. Since the details of the support 1 are the same as those of the support 1 of the abrasive of the present invention described later, detailed description thereof will be omitted.

<Abrasive layer forming process>
In the polishing layer forming step S2, the polishing layer is formed on the surface side of the support. As shown in FIG. 6, the polishing layer forming step S2 includes a preparation step S21 and a polishing layer forming step S22. By the polishing layer forming step S2, for example, a polishing material in which the polishing layer 2 as shown in FIG. 7 is formed on the surface side of the support 1 can be obtained. The polishing layer 2 contains abrasive grains 21 and a binder 22. Further, as shown in FIG. 7, the polishing layer 2 has a plurality of polishing portions 2b separated by grooves 2a on its surface.

(Preparation process)
In the preparation step S21, a composition for a polishing layer containing the abrasive grains 21 and the binder 22 is prepared.

Specifically, a composition for an abrasive layer containing a material for forming the abrasive grains 21 and the binder 22 is prepared as a coating liquid. Since the content of the abrasive grains 21 in the solid content is the content of the abrasive grains 21 in the polishing portion 2b after production, the amount of the solid content is adjusted so that the content in the polishing portion 2 becomes a desired value. Determine as appropriate.

Further, in order to control the viscosity and fluidity of the coating liquid, a diluent such as water or alcohol is added. By this dilution, a part of the abrasive grains 21 contained in the polishing portion 2b can be projected from the surface of the binder 22. That is, by adding the diluent, the thickness of the binder 22 can be reduced and the amount of protrusion of the abrasive grains 21 can be increased when the composition for the polishing layer is dried in the polishing layer forming step. Therefore, this dilution makes it possible to develop a high polishing rate from the initial stage of polishing.

(Abrasive layer forming process)
In the polishing layer forming step S22, the polishing layer 2 is formed by printing the composition for the polishing layer prepared in the preparation step S21. The polishing layer forming step S22 includes a coating step and a drying step.

<Coating process>
In the coating step, the composition for the polishing layer is coated on the surface of the support 1.

Specifically, using the coating liquid prepared in the preparation step S21, the polishing layer 2 has a plurality of polishing portions 2b and grooves 2a arranged between the polishing portions 2b on the surface of the support 1 by a printing method. To form. In order to form the groove 2a, a mask having a shape corresponding to the shape of the groove 2a is prepared, and the coating liquid is printed through the mask. As this printing method, for example, screen printing, metal mask printing, or the like can be used.

The thickness of the polished portion 2b can be adjusted mainly by the thickness of the mask and the amount of coating. Therefore, in this coating step, it is preferable to adjust the coating amount of the composition for the polishing layer so that the average thickness of the polishing portion 2b is a desired value.

<Drying process>
In the drying step, the coating liquid (composition for the polishing layer) after the coating step is heated and dried. By this heat drying, the coating liquid is cured and the polishing layer 2 is formed. This drying step is performed by removing the mask.

The lower limit of the heating temperature in the drying step is preferably 80 ° C., more preferably 100 ° C. On the other hand, as the upper limit of the heating temperature, 300 ° C. is preferable, and 200 ° C. is more preferable. If the heating temperature is less than the above lower limit, the composition for the polishing layer may not be sufficiently cured, the amount of wear may increase, and the life of the obtained abrasive may be shortened. On the contrary, if the heating temperature exceeds the upper limit, the polishing portion 2b may be deteriorated by heat.

The heating time in the drying step depends on the heating temperature, but the lower limit of the heating time is preferably 2 hours, more preferably 2.5 hours. On the other hand, the upper limit of the heating time is preferably 20 hours, more preferably 18 hours. If the heating time is less than the above lower limit, the composition for the polishing layer may not be sufficiently cured, the amount of wear may increase, and the life of the obtained abrasive may be shortened. On the contrary, if the heating time exceeds the upper limit, the production efficiency may decrease.

<Advantage>
In the method for producing the abrasive, a molten resin kneaded with a supercritical fluid is filled in a molding die 100, and the molding die 100 is widened in the plate thickness direction. By widening the molding die 100 in the plate thickness direction, the supercritical fluid foams, and a region including the pores 10 is formed in the central portion of the support 1 in the thickness direction. Due to the region including the pores 10 of the support 1, the abrasive produced by the method for producing the abrasive can have appropriate impact resistance and flexibility while having heat resistance. Further, in the method for producing the abrasive, the abrasive layer 2 can be directly laminated on the surface side of the support 1, and it is not necessary to use a base material. Therefore, since the method for manufacturing the abrasive does not require a sticking step between the base material and the support, the manufacturing efficiency is excellent, and it is possible to prevent a decrease in the manufacturing yield and peeling when the abrasive is used due to the sticking step. .. Further, in the abrasive material produced by the method for producing the abrasive material, the porosity on the front surface side and the back surface side of the support 1 is lower than that in the central portion in the thickness direction, so that the front surface and the back surface of the support 1 have irregularities. The number is small, and the polishing layer 2 can be easily laminated on the front surface side and attached to the surface plate of the polishing machine on the back surface side.

[Abrasive]
As shown in FIGS. 7 and 8, the abrasive material according to the embodiment of the present invention includes a plate-shaped support 1 and a polishing layer 2 laminated on the surface side of the support 1. The abrasive can be produced by the above-mentioned method for producing the abrasive.

<Support>
As shown in FIG. 7, the support 1 includes a core region 11 including pores 10 and a large number of pores 10 formed in the central portion in the thickness direction of the support 1, and a core formed on the front surface side and the back surface side. It has a solid region 12 having a lower porosity than the region 11. That is, the porosity of the support 1 is maximum in the central portion in the thickness direction and small in the front surface side and the back surface side.

The support 1 is composed of a single layer. That is, since the support 1 is not a stack of a plurality of layers in the thickness direction, there is no layer boundary. By forming the support 1 into a single layer in this way, it is possible to improve the effect of suppressing the occurrence of peeling when the abrasive is used.

The main component of the support 1 can be the same as the main component of the molten resin described in the method for producing the abrasive.

The shape and size of the support 1 are appropriately determined according to the shape and size of the surface plate of the polishing machine used, and are, for example, an annular shape having an outer diameter of 200 mm or more and 2022 mm or less and an inner diameter of 100 mm or more and 658 mm or less. be able to. When the outer shape is large, from the viewpoint of handleability of the abrasive material, a plurality of supports 1 arranged side by side on a flat surface may be supported by the surface plate of the polishing machine. In this case, the individual support 1 may have a shape in which the annular support 1 is divided into four or eight by a straight line passing through the center thereof, or a square shape having a side of 140 mm or more and 160 mm or less.

The lower limit of the average thickness of the support 1 is preferably 0.5 mm, more preferably 0.8 mm. On the other hand, as the upper limit of the average thickness of the support 1, 3 mm is preferable, and 2 mm is more preferable. If the average thickness of the support 1 is less than the above lower limit, the strength of the abrasive may be insufficient. On the contrary, if the average thickness of the support 1 exceeds the above upper limit, it may be difficult to attach the support 1 to the surface plate of the polishing machine, or the flexibility of the support 1 may be insufficient.

The lower limit of the average diameter of the pores 10 is preferably 0.1 μm, more preferably 1 μm. On the other hand, the upper limit of the average diameter of the pores 10 is preferably 10 μm, more preferably 8 μm. If the average diameter of the pores 10 is less than the above lower limit, it becomes difficult to sufficiently increase the porosity, and the impact resistance and flexibility of the abrasive may be insufficient. On the contrary, if the average diameter of the pores 10 exceeds the above upper limit, the strength of the support 1 may be insufficient. The "average diameter of the pores" refers to the average of the area-equivalent diameters of the pores obtained by observing an arbitrary cross section of 1 mm × 1 mm of the support.

The lower limit of the average porosity of the support 1 is preferably 20% by volume, more preferably 30% by volume. On the other hand, as the upper limit of the average porosity of the support 1, 80% by volume is preferable, and 70% by volume is more preferable. If the average porosity of the support 1 is less than the above lower limit, the impact resistance and flexibility of the abrasive may be insufficient. On the contrary, when the average porosity of the support 1 exceeds the above upper limit, the pores 10 also enter the solid region 12, and the front surface and the back surface of the support 1 are liable to be uneven. Therefore, it may be difficult to laminate the polishing layer 2 on the front surface side or attach the polishing layer 2 to the surface plate of the polishing machine on the back surface side. The "average porosity" is obtained by dividing the total area of pores obtained by observing an arbitrary cross section of 1 mm in the width direction by the cross-sectional area of the support, including the entire thickness direction of the support.

It is preferable that the solid region 12 substantially does not include the pores 10. The lower limit of the average thickness of the solid region 12 is preferably 50 μm, more preferably 100 μm. If the average thickness of the solid region 12 is less than the above lower limit, unevenness is likely to occur on the front surface and the back surface of the support 1, so that the polishing layer 2 is laminated on the front surface side and the back surface side of the polishing machine on the surface plate. May be difficult to attach. On the other hand, the upper limit of the average thickness of the solid region 12 is not particularly limited, but 200 μm is preferable from the viewpoint of ensuring the thickness of the core region 11.

The upper limit of the arithmetic mean roughness Ra of the surface of the support 1 is preferably 0.1 μm, more preferably 0.05 μm. If the arithmetic average roughness Ra is less than the above lower limit, it may be difficult to laminate the polishing layer 2 on the surface side. On the other hand, the lower limit of the arithmetic mean roughness Ra is not particularly limited, and the smaller the lower limit, the better. That is, the arithmetic mean roughness Ra may be 0.

The arithmetic mean roughness Ra on the back surface of the support 1 can be the same as the arithmetic roughness Ra on the front surface of the support 1.

The lower limit of the ratio of the specific gravity of the support 1 to the specific gravity determined by the material constituting the support 1 is preferably 0.2, more preferably 0.3. On the other hand, as the upper limit of the specific gravity ratio, 0.7 is preferable, and 0.5 is more preferable. If the specific gravity ratio is less than the lower limit, the strength of the support 1 may be insufficient. On the contrary, if the specific gravity ratio exceeds the upper limit, the flexibility of the support 1 may be insufficient.

The lower limit of the bending elastic gradient of the support 1 is preferably 60 N / cm, more preferably 70 N / cm. On the other hand, the upper limit of the bending elastic gradient of the support 1 is preferably 90 N / cm, more preferably 80 N / cm. If the bending elastic gradient of the support 1 is less than the above lower limit, the strength of the support 1 may be insufficient. On the contrary, if the bending elastic gradient of the support 1 exceeds the above upper limit, the flexibility of the support 1 may be insufficient. The "bending elastic gradient" was calculated from the initial straight line portion of the load-deflection curve when a 50 mm × 150 mm test piece was supported at both ends with a 100 mm span in a plan view and a load was applied to the central portion at 50 mm / min. Represents the load required for 1 cm deformation.

<Abrasive layer>
As shown in FIGS. 7 and 8, the polishing layer 2 includes abrasive grains 21 and a binder 22. Further, the polishing layer 2 has a plurality of polishing portions 2b on the surface thereof, which are separated by grooves 2a.

(Abrasive grain)
Examples of the abrasive grains 21 include diamond abrasive grains, alumina abrasive grains, silica abrasive grains, ceria abrasive grains, silicon carbide abrasive grains, and the like. Of these, diamond abrasive grains, which are harder than other abrasive grains, are preferable. By using the abrasive grains 21 as diamond abrasive grains, the polishing power can be improved and the polishing rate can be further improved.

The diamond of the diamond abrasive grains may be a single crystal or a polycrystal, or may be a diamond treated with Ni coating or the like. Of these, single crystal diamond and polycrystalline diamond are preferable. Single crystal diamonds are harder and have higher grinding power than other diamonds. Further, since polycrystalline diamond is easily cleaved in the microcrystal units constituting the polycrystalline and the blinding is unlikely to proceed, the decrease in the polishing rate is small even after long-term polishing.

The average particle diameter of the abrasive grains 21 is appropriately selected from the viewpoint of the polishing rate and the surface roughness of the work piece after polishing. The lower limit of the average particle size of the abrasive grains 21 is preferably 2 μm, more preferably 10 μm, and even more preferably 15 μm. On the other hand, the upper limit of the average particle size of the abrasive grains 21 is preferably 50 μm, more preferably 45 μm, and even more preferably 30 μm. If the average particle size of the abrasive grains 21 is less than the above lower limit, the polishing power of the abrasive material may be insufficient and the polishing rate may decrease. On the contrary, if the average particle diameter of the abrasive grains 21 exceeds the above upper limit, the polishing accuracy may decrease. Here, the "average particle size" means a 50% value (50% particle size, D50) of a volume-based cumulative particle size distribution curve measured by a laser diffraction method or the like.

As the lower limit of the content of the abrasive grains 21 in the polishing layer 2, 3% by volume is preferable, 4% by volume is more preferable, and 8% by volume is further preferable. On the other hand, as the upper limit of the content of the abrasive grains 21, 55% by volume is preferable, 45% by volume is more preferable, and 35% by volume is further preferable. If the content of the abrasive grains 21 is less than the above lower limit, the polishing power of the polishing layer 2 may be insufficient. On the contrary, if the content of the abrasive grains 21 exceeds the above upper limit, the polishing layer 2 may not be able to hold the abrasive grains 21.

(binder)
The main component of the binder 22 of the polishing layer 2 is not particularly limited, and examples thereof include a resin or an inorganic substance.

Examples of the resin include resins such as polyurethane, polyphenol, epoxy, polyester, cellulose, ethylene copolymer, polyvinyl acetal, polyacrylic, acrylic ester, polyvinyl alcohol, polyvinyl chloride, polyvinyl acetate, and polyamide. Of these, polyacrylic, epoxy, polyester and polyurethane, which can easily ensure good adhesion to the support 1, are preferable. The resin may be at least partially crosslinked.

Examples of the inorganic substance include silicates, phosphates, polyvalent metal alkoxides and the like. Of these, silicates with high abrasive grain retention are preferable. Examples of such a silicate include sodium silicate and potassium silicate.

The main component of the binder 22 is preferably an inorganic substance. By using the main component of the binder 22 as an inorganic substance in this way, the holding power of the abrasive grains 21 can be enhanced, and it is possible to prevent the abrasive grains 21 from being shed before spilling. Therefore, the grinding force is further increased.

The binder 22 may appropriately contain various auxiliaries and additives such as a dispersant, a coupling agent, a surfactant, a lubricant, an antifoaming agent, and a colorant, depending on the purpose.

(groove)
In FIG. 8, the grooves 2a are arranged in a grid pattern at equal intervals on the surface of the polishing layer 2. That is, the shape of the plurality of polishing portions 2b of the polishing layer 2 separated by the grooves 2a is a regularly arranged block pattern. The bottom surface of the groove 2a is formed by the surface of the support 1.

The lower limit of the average width of the groove 2a is preferably 0.3 mm, more preferably 0.5 mm. On the other hand, as the upper limit of the average width of the groove 2a, 10 mm is preferable, and 8 mm is more preferable. If the average width of the groove 2a is less than the above lower limit, the polishing powder generated by polishing may be clogged in the groove 2a. On the contrary, when the average width of the groove 2a exceeds the above upper limit, the work piece tends to fall into the groove 2a during polishing, so that the work piece may be damaged.

As the lower limit of the average area of the polished portion 2b, 1 mm ² is preferable, and 2 mm ² is more preferable. On the other hand, as the upper limit of the average area of the polished portion 2b, 150 mm ² is preferable, and 130 mm ² is more preferable. If the average area of the polishing portion 2b is less than the above lower limit, the polishing portion 2b may peel off from the support 1. On the contrary, if the average area of the polishing portion 2b exceeds the above upper limit, the contact area of the polishing layer 2 with the work piece becomes large during polishing, so that the polishing rate may decrease due to frictional resistance.

As the lower limit of the area occupancy of the plurality of polishing portions 2b with respect to the entire polishing layer 2, 5% is preferable, and 10% is more preferable. On the other hand, the upper limit of the area occupancy of the polished portion 2b is preferably 60%, more preferably 55%. If the area occupancy of the polishing portion 2b is less than the above lower limit, the pressure applied during polishing is too concentrated on the polishing portion 2b, which may cause the polishing portion 2b to peel off from the support 1. On the contrary, if the area occupancy of the polishing portion 2b exceeds the upper limit, the contact area of the polishing layer 2 with the work piece becomes large during polishing, so that the polishing rate may decrease due to frictional resistance. In addition, "the area of the whole polishing layer" is a concept including the area of the groove when the polishing layer has a groove.

The lower limit of the average thickness of the polishing layer 2 (the average thickness of only the polished portion 2b portion) is preferably 1000 μm, more preferably 1500 μm, and even more preferably 2000 μm. On the other hand, the upper limit of the average thickness of the polishing layer 2 is preferably 4000 μm, more preferably 3500 μm, and even more preferably 3200 μm. If the average thickness of the polishing layer 2 is less than the above lower limit, the durability of the polishing layer 2 may be insufficient and the life of the abrasive may be shortened. On the contrary, if the average thickness of the polishing layer 2 exceeds the above upper limit, the polishing portion 2b may easily fall down due to the load applied to the interface between the polishing layer 2 and the support 1 due to the moment generated during polishing, or the polishing material. May increase the manufacturing cost of.

<Advantage>
Since the support 1 contains the pores 10, the abrasive can have appropriate impact resistance and flexibility while having heat resistance. Further, in the polishing material, the polishing layer 2 is laminated on the surface side of the support 1, and it is not necessary to use a base material. For this reason, the abrasive does not require a sticking step between the base material and the support 1 in its manufacture, so that it is excellent in manufacturing efficiency and prevents a decrease in manufacturing yield and peeling when the abrasive is used due to the sticking step. it can. Further, in the abrasive material, since the porosity on the front surface side and the back surface side of the support 1 is lower than that in the central portion in the thickness direction, the surface and the back surface of the support 1 have less unevenness, and the polishing layer 2 toward the front surface side It can be easily laminated and attached to the surface plate of the polishing machine on the back side.

[Other Embodiments]
The present invention is not limited to the above embodiment, and can be implemented in various modifications and improvements in addition to the above embodiment.

In the above embodiment, the case where the temperature of the molding die main body and the portion where the movable part is in contact with the concave portion of the molding die can be controlled has been described, but the temperature control method is another method, for example, a method of controlling the temperature of the entire molding die. May be used.

Alternatively, it is possible to set the temperature to room temperature without positively controlling the temperature, and in this case, the function of controlling the temperature of the molding die can be unnecessary.

In the above embodiment, the grooves of the abrasive material are formed in a grid pattern at equal intervals, but the spacing and the planar shape of the grid are not limited to the above embodiment. Further, in the above embodiment, the bottom surface of the groove is the surface of the base material, but the depth of the groove is smaller than the average thickness of the polishing layer, and the groove does not have to reach the surface of the base material.

The planar shape of the groove does not have to be a grid shape, and may be, for example, a shape in which polygons other than a quadrangle are repeated, a circular shape, a shape having a plurality of parallel lines, or a concentric circular shape. Further, the planar shape of the groove may be a striped shape arranged in only one direction.

Alternatively, the grooves may be formed so that the plurality of convex portions are arranged in a staggered pattern. That is, a plurality of convex portions are arranged in a plurality of parallel rows at equal intervals, pass through the center of the convex portions included in one row, and are orthogonal to the one row. The arrangement may be such that the center of the convex portion of the row adjacent to the row is not located.

Further, the polishing layer may have a structure having no groove.

Further, the polishing layer of the abrasive may contain other particles. Examples of such other particles include fillers. By including the filler in the polishing layer in this way, the elastic modulus of the binder can be improved and the polishing rate can be increased.

Examples of the filler include oxides such as alumina, silica, cerium oxide, magnesium oxide, zirconia and titanium oxide, and composite oxides such as silica-alumina, silica-zirconia and silica-magnesia. These may be used alone or in combination of two or more as required. Of these, alumina, which can obtain high polishing power, is preferable.

The average particle size of the filler depends on the average particle size of the abrasive grains, but the lower limit of the average particle size of the filler is preferably 0.01 μm, more preferably 2 μm. On the other hand, the upper limit of the average particle size of the filler is preferably 20 μm, more preferably 15 μm. If the average particle size of the filler is less than the lower limit, the polishing rate may not be improved due to insufficient effect of the filler on improving the elastic modulus of the binder. On the other hand, if the average particle size of the filler exceeds the upper limit, the filler may hinder the polishing power of the abrasive grains.

Further, the average particle size of the filler is preferably smaller than the average particle size of the abrasive grains. The lower limit of the ratio of the average particle size of the filler to the average particle size of the abrasive grains is preferably 0.1, more preferably 0.2. On the other hand, as the upper limit of the ratio of the average particle size of the filler to the average particle size of the abrasive grains, 0.8 is preferable, and 0.6 is more preferable. If the ratio of the average particle size of the filler to the average particle size of the abrasive grains is less than the above lower limit, the polishing rate may not be improved due to the insufficient effect of the filler on improving the elastic modulus of the binder. On the contrary, if the ratio of the average particle size of the filler to the average particle size of the abrasive grains exceeds the upper limit, the filler may hinder the polishing power of the abrasive grains.

The content of the filler in the polishing layer depends on the content of the abrasive grains, but the lower limit of the content of the filler in the polishing layer is preferably 15% by volume, more preferably 30% by volume. On the other hand, as the upper limit of the content of the filler, 75% by volume is preferable, and 72% by volume is more preferable. If the content of the filler is less than the lower limit, the polishing rate may decrease due to insufficient effect of the filler on improving the elastic modulus of the binder. On the contrary, when the content of the filler exceeds the upper limit, the filler may hinder the polishing power of the abrasive grains.

The abrasive may further include an adhesive layer laminated on the back surface side of the support. The adhesive layer is a layer for attaching the polishing material to the surface plate of the polishing machine.

The adhesive used for this adhesive layer is not particularly limited, and examples thereof include a reactive adhesive, an instant adhesive, a hot melt adhesive, and an adhesive which is a replaceable adhesive.

As the adhesive used for this adhesive layer, an adhesive is preferable. By using an adhesive as the adhesive used for the adhesive layer, the abrasive can be peeled off from the polishing machine and replaced, so that the replacement work of the abrasive becomes easy. Such adhesives are not particularly limited, but are, for example, acrylic adhesives, acrylic-rubber adhesives, natural rubber adhesives, synthetic rubber adhesives such as butyl rubber, silicone adhesives, and polyurethane adhesives. Examples include agents.

The lower limit of the average thickness of the adhesive layer is preferably 0.05 mm, more preferably 0.1 mm. On the other hand, the upper limit of the average thickness of the adhesive layer is preferably 0.3 mm, more preferably 0.2 mm. If the average thickness of the adhesive layer is less than the above lower limit, the adhesive force may be insufficient and the abrasive material may be peeled off from the polishing machine. On the contrary, if the average thickness of the adhesive layer exceeds the upper limit, the workability may be lowered, for example, the thickness of the adhesive layer may hinder the cutting of the abrasive into a desired shape.

When the abrasive material includes the adhesive layer, the method for producing the abrasive material further includes an adhesive layer attaching step. In the adhesive layer attaching step, the adhesive layer is laminated on the back surface side of the support. Specifically, for example, a pre-formed tape-shaped adhesive layer is attached to the back surface of the support. Although this adhesive layer attaching step can be performed after the support forming step, it is preferably performed after the polishing layer laminating step in order to avoid deterioration due to heat in the polishing layer laminating step.

By using the method for producing an abrasive of the present invention, the abrasive layer can be directly laminated on the surface side of the support. The abrasive material produced by the method for producing the abrasive material and the abrasive material are excellent in production efficiency by directly laminating the abrasive layer on the surface side of the support, eliminating the need for a sticking process between the base material and the support. , It is possible to prevent a decrease in manufacturing yield due to the pasting process and peeling when using an abrasive.

1 Support 10 Pore 11 Core area 12 Solid area 2 Polishing layer 21 Abrasive grain 22 Binder 2a Groove 2b Polishing part 100 Molding mold 101 Molding mold body 102 Moving part 103 Recession 104 Injection pipe

Claims (8)

The process of forming a plate-shaped support and
A step of forming a polishing layer containing abrasive grains and a binder on the surface side of the support is provided.
As the support forming step,
The process of kneading the supercritical fluid with the molten resin,
A step of filling the molten resin after the mixing step into a molding mold having a recess in which the support can be formed, and a step of filling the molded resin.
A method for producing an abrasive, which comprises a step of widening the concave portion of the molding die after the filling step in the plate thickness direction of the support to be formed. The method for producing an abrasive according to claim 1, wherein the supercritical fluid is nitrogen. In the widening step, the surface temperature of the concave portion of the molding die is made lower than the resin temperature of the central portion in the plate thickness direction.
The method for producing an abrasive according to claim 1 or 2, wherein the temperature difference is 50 ° C. or higher and 150 ° C. or lower. The method for producing an abrasive according to claim 1, 2, or 3, wherein the main component of the molten resin is polycarbonate. With a plate-shaped support
It is laminated on the surface side of this support and is provided with a polishing layer containing abrasive grains and a binder.
The support contains pores and
An abrasive in which the porosity of the support is maximum in the central portion in the thickness direction and is small on the front surface side and the back surface side. The abrasive according to claim 5, wherein the support is a single layer. The abrasive according to claim 5 or 6, wherein the arithmetic average roughness Ra of the surface of the support is 0.1 μm or less. The abrasive according to claim 5, claim 6 or claim 7, wherein the average porosity of the support is 20% by volume or more and 80% by volume or less.

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