Preparation method of non-woven fabric grinding wheel and non-woven fabric grinding wheel

Abstract

The invention provides a preparation method of a non-woven fabric grinding wheel and the non-woven fabric grinding wheel. The preparation method of the non-woven fabric grinding wheel comprises the following steps: crushing a non-woven fabric into fragment fibers with the size of 1-2mm; the fragment fibers and the foaming slurry are kneaded and compressed to obtain a slurry-containing material; and placing the slurry-containing material in a mold, compressing and fixing, and baking. According to the technical scheme adopted by the invention, the non-woven fabric is crushed into the fragment fibers, the fragment fibers and the foaming slurry are used as raw materials, and the non-woven fabric grinding wheel with the wheel surface being small in flatness can be prepared through kneading, compression, mold pressing and baking. The prepared non-woven fabric grinding wheel is integrally foamed and formed through fragment fibers and foaming slurry, the grinding force of a grinding base material is stable, and the elasticity is good. More importantly, the grinding base material is fragment fiber, the size of the grinding base material is 1-2 mm, the small size of the grinding base material can greatly reduce shape fluctuation caused by the alternating process of the grinding base material during grinding, and defects caused by excessive grinding of the hole edge of the PCB can be effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of grinding tools, and in particular to a preparation method of a non-woven fabric grinding wheel and the non-woven fabric grinding wheel. Background Art

[0002] In the PCB grinding industry, there are mainly grinding products such as ceramic grinding wheels, non-woven grinding wheels and nylon grinding wheels. Among them, non-woven grinding wheels have attracted much attention because they do not damage the surface of the workpiece, do not change the size of the workpiece during grinding, are durable, and have high finish. Currently, non-woven grinding wheels are divided into two categories: tight-fitting and radial. Use non-woven sandblasting or roller sanding to attach abrasives to the fibers, bake to form semi-finished non-woven fabrics, and then process the semi-finished non-woven fabrics to roll up and dip in glue to form a tight-fitting grinding wheel. Or cut the semi-finished non-woven fabrics into small strips to form grinding wheels, and make radial grinding wheels by dipping or foaming.

[0003] Whether it is a radial grinding wheel or a winding grinding wheel, the sheet structure of the non-woven fabric is retained to the maximum extent, and the grinding substrate (non-woven fabric) is in sheet form (such as Figure 1 As shown in the figure, the surface of the grinding wheel is relatively flat, and there are gullies between the substrates. When this type of grinding wheel is used to alternately grind the substrates during the grinding process, the shape fluctuations caused by the alternating process can easily cause excessive grinding of the edges of the PCB holes and cause defects (such as Figure 2 If the grinding plate current is reduced to slow down the grinding speed and alleviate the shape fluctuation caused by the alternating process, insufficient copper reduction will occur in other locations. Summary of the invention

[0004] Based on the above problems, the purpose of the present invention is to provide a method for preparing a non-woven fabric grinding wheel and a non-woven fabric grinding wheel thereof. The preparation method can be used to obtain a non-woven fabric grinding wheel with a relatively low flatness of the wheel surface, which can greatly reduce the fluctuation effect caused by the alternating process of the substrate during grinding, and can effectively reduce the risk of hole edge grinding defects when grinding PCB boards.

[0005] To achieve the above object, the present invention provides a method for preparing a non-woven grinding wheel, comprising the steps of: (1) Crushing the non-woven fabric into fragmented fibers with a size of 1 to 2 mm; (2) kneading the fiber fragments and the foamed slurry and compressing them to obtain a slurry material; (3) Placing the slurry material in a mold, compressing and fixing it, and then baking it.

[0006] In the technical solution adopted by the present invention, a non-woven fabric grinding wheel with a relatively low flatness on the wheel surface can be obtained by crushing the non-woven fabric into fragmented fibers, using the fragmented fibers and foaming slurry as raw materials, and kneading, compressing, molding, and baking. The obtained non-woven fabric grinding wheel is formed by integrally foaming the fragmented fibers and the foaming slurry, and the grinding force of the grinding substrate is stable and the elasticity is good. More importantly, the grinding substrate is a fragmented fiber with a size of 1 to 2 mm. Its small size can greatly reduce the shape fluctuation caused by the alternating process of the grinding substrate during grinding, and can effectively reduce the defects caused by excessive grinding of the hole edge of the PCB board.

[0007] As a technical solution of the present invention, the weight of the non-woven fabric is 60-120 g / m 2 The non-woven fabric includes at least one of polypropylene non-woven fabric, polyester non-woven fabric and polyamide non-woven fabric.

[0008] As a technical solution of the present invention, the weight ratio of the fragment fibers to the foaming slurry is 1:0.7~1.0.

[0009] As a technical solution of the present invention, the raw materials for preparing the foaming slurry include: 40 to 60 parts by weight of abrasive, 20 to 40 parts by weight of epoxy resin, 5 to 15 parts by weight of epoxy diluent, 2 to 10 parts by weight of latent curing agent, 2 to 10 parts by weight of foaming microspheres and 0.5 to 3.0 parts by weight of auxiliary agent.

[0010] As a technical solution of the present invention, the preparation method of the foaming slurry includes: stirring the formulated amount of the abrasive, the formulated amount of the epoxy resin, the formulated amount of the epoxy diluent, the formulated amount of the latent curing agent, the formulated amount of the foaming microspheres and the formulated amount of the auxiliary agent in a disperser for 1.0~2.0h to obtain the foaming slurry.

[0011] As a technical solution of the present invention, the Dv50 of the abrasive is 1-120 μm, and the abrasive includes at least one of silicon carbide, aluminum oxide, silicon dioxide and boron nitride.

[0012] As a technical solution of the present invention, the viscosity of the epoxy resin at 25° C. is below 20,000 cps, and the epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and phenol novolac epoxy resin.

[0013] As a technical solution of the present invention, the viscosity of the epoxy diluent at 25° C. is below 100 cps, and the epoxy diluent is a reactive diluent containing at least one functional group.

[0014] As a technical solution of the present invention, the Dv50 of the latent curing agent is less than 10 μm, and the latent curing agent includes at least one of dicyandiamide and its derivatives, organic acid hydrazides, BF3 amine complexes and imidazole compounds.

[0015] As a technical solution of the present invention, the Dv50 of the foamed microspheres is 5-50 μm, the initial expansion temperature is 140-160° C., and the optimal expansion temperature is 160-180° C.; As a technical solution of the present invention, the auxiliary agent includes at least one of a plasticizer, a diluent, a thickener, a pH regulator, a coupling agent, a catalyst, an anti-settling agent and a pigment.

[0016] As a technical solution of the present invention, the kneading is carried out in a kneader, and the kneading time is 3 to 4 hours.

[0017] As a technical solution of the present invention, the compression in step (2) can be performed using a roller device with a spacing of 1 to 2 mm.

[0018] As a technical solution of the present invention, the weight of the slurry material placed in the mold is 4.11~4.73kg.

[0019] As a technical solution of the present invention, the compression in step (3) can be performed by using a press to compress the end faces of the mold so that the distance between the two end faces is 650-850 mm.

[0020] As a technical solution of the present invention, a hollow tube is provided in the middle of the mold, and the slurry material is contained in the cavity surrounded by the mold and the hollow tube. The hollow tube includes any one of a bakelite tube, a cotton tube, a paper tube, a glass fiber tube and an aluminum tube.

[0021] As a technical solution of the present invention, the baking adopts a gradient temperature increase method.

[0022] As a technical solution of the present invention, the baking step includes first heating the temperature to 100-120°C in a blast oven and keeping it warm for 1-2 hours, then heating the temperature to 130-150°C and keeping it warm for 1-2 hours, and then heating the temperature to 160-180°C and keeping it warm for 2-4 hours.

[0023] Another aspect of the present invention provides a non-woven fabric grinding wheel prepared by the above-mentioned method for preparing a non-woven fabric grinding wheel, wherein the flatness of the wheel surface is less than 2 mm. The non-woven fabric grinding wheel of the present invention has a relatively low flatness of the wheel surface, and its small size can greatly reduce the shape fluctuation caused by the alternating process of the grinding substrate during grinding, and can effectively reduce the defects caused by excessive grinding of the hole edge of the PCB board. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1Schematic diagram of a non-woven grinding wheel in the prior art.

[0025] Figure 2 It is a schematic diagram of a non-woven grinding wheel in the prior art grinding a PCB board with holes.

[0026] Figure 3 Schematic diagram of the nonwoven grinding wheel of the present invention.

[0027] Figure 4 It is a schematic diagram of the non-woven fabric grinding wheel of the present invention grinding a PCB board with holes. DETAILED DESCRIPTION

[0028] The structure of the nonwoven grinding wheel of the present invention can be as follows Figure 3 As shown, it is a hollow cylindrical structure with a hollow tube in the middle for support. The hollow tube is a hollow cylindrical tube made of bakelite tube, cotton tube, paper tube, glass fiber tube or aluminum tube. The grinding substrate of the non-woven grinding wheel is fragmented fiber with a size of 1~2mm, so the surface flatness of the non-woven grinding wheel is less than 2mm. Its small size can greatly reduce the shape fluctuation caused by the alternating process of the grinding substrate during grinding, and can effectively reduce the defects caused by excessive grinding of the hole edges of the PCB board. Figure 4 As shown, Figure 2 In comparison, after being ground by the non-woven fabric grinding wheel of the present invention, the hole edges of the PCB board are not obviously damaged.

[0029] The method for preparing the non-woven fabric grinding wheel of the present invention comprises the steps of: (1) Crushing the non-woven fabric into fragmented fibers with a size of 1 to 2 mm; (2) kneading the fiber fragments and the foaming slurry and compressing them to obtain a slurry material; (3) Place the slurry material in the mold, compress and fix it, and then bake it.

[0030] The nonwoven fabric in step (1) comprises at least one of polypropylene nonwoven fabric, polyester nonwoven fabric and polyamide nonwoven fabric. The weight of the nonwoven fabric is 60-120 g / m 2 As an example, it can be, but not limited to, 60 g / m 2 , 70g / m 2 , 80g / m 2 , 90g / m 2 , 100g / m 2 , 110g / m 2 , 120g / m 2 .

[0031] In step (2), the weight ratio of the fiber fragments to the foaming slurry is 1:0.7-1.0. As an example, the weight ratio may be, but is not limited to, 1:0.7, 1:0.8, 1:0.9, 1:1.0. The raw materials for preparing the foaming slurry include: 40-60 parts by weight of abrasive, 20-40 parts by weight of epoxy resin, 5-15 parts by weight of epoxy diluent, 2-10 parts by weight of latent curing agent, 2-10 parts by weight of foaming microspheres, and 0.5-3.0 parts by weight of auxiliary agent. The Dv50 of the abrasive is 1-120 μm, and the abrasive includes at least one of silicon carbide, aluminum oxide, silicon dioxide, and boron nitride. Furthermore, silicon carbide, aluminum oxide, silicon dioxide, and boron nitride may be hollow or solid. The abrasive may be, but is not limited to, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 parts. The viscosity of the epoxy resin at 25° C. is below 20,000 cps, and the epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, and phenol novolac epoxy resin. The epoxy resin may be, but is not limited to, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 parts. The viscosity of the epoxy diluent at 25°C is below 100 cps, and the epoxy diluent is an active diluent containing at least one functional group, such as dipropylene glycol diglycidyl ether, HK-66 (alkylene glycidyl ether), 501 (butyl glycidyl ether), 622 (1,4-butanediol diglycidyl ether), 669 (ethylene glycol diglycidyl ether), 690 (phenyl glycidyl ether), X-632 (polypropylene glycol diglycidyl ether), AGE (C12-14 fatty glycidyl ether), 692 (benzyl glycidyl ether), X-652 (1,6-hexanediol diglycidyl ether), etc. The epoxy diluent can be, but is not limited to, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, and 15 parts. The Dv50 of the latent curing agent is less than 10 μm, and the latent curing agent includes at least one of dicyandiamide and its derivatives, organic acid hydrazides, BF3 amine complexes and imidazole compounds. The latent curing agent can be, but is not limited to, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, and 10 parts. The Dv50 of the foamed microsphere is 5-50 μm, the initial expansion temperature is 140-160°C, and the optimal expansion temperature is 160-180°C. The foamed microsphere can be, but is not limited to, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, and 10 parts. The auxiliary agent includes at least one of a plasticizer, a diluent, a thickener, a pH adjuster, a coupling agent, a catalyst, an anti-settling agent, and a pigment.The plasticizer may be di(2-ethylhexyl) phthalate (DEHP), dioctyl phthalate (DOP), di-n-octyl phthalate (DNOP or DnOP), butyl benzyl phthalate (BBP), di-sec-octyl phthalate (DCP), dicyclohexyl phthalate (DCHP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), dimethyl phthalate (DMP), diethyl phthalate (DEP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP). The diluent may be banana water or thinner. The thickener may be methylcellulose, hydroxypropyl methylcellulose, sodium carboxymethylcellulose, hydroxyethyl cellulose, starch, gelatin, sodium alginate, casein, guar gum, chitosan, gum arabic, xanthan gum, soybean protein glue, natural rubber, lanolin, agar, polyacrylamide, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, carbomer resin, polyacrylic acid, sodium polyacrylate, polyacrylate copolymer emulsion, butadiene rubber, styrene-butadiene rubber, polyurethane, modified polyurea, low molecular weight polyethylene wax, etc. The pH regulator may be a weak acid, a weak base or a buffer. The coupling agent may be KH550, KH560, KH570, KH792, DL602 or DL171, etc. The catalyst may be 2,4,6-tris(dimethylaminomethyl)phenol, and the anti-settling agent may be polyamide wax. The auxiliary agent may be, but is not limited to, 0.5 parts, 1.0 parts, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts. The epoxy resin is cured under the action of the latent curing agent to combine the abrasive and the fragmented fiber into one. The epoxy diluent can reduce the viscosity of the curing system, increase fluidity, and improve operability. Adding small-particle foaming microspheres can produce a foamed non-woven grinding wheel. The preparation method of the foaming slurry includes: stirring the abrasive, the epoxy resin, the epoxy diluent, the latent curing agent, the foaming microspheres and the auxiliary agent in a disperser for 1.0 to 2.0 hours to obtain the foaming slurry.

[0032] The kneading in step (2) can be carried out in a kneading machine, and the kneading time is 3 to 4 hours. After kneading, a roller device with a spacing of 1 to 2 mm can be used to compress and squeeze out excess slurry. The weight of the slurry material placed in the mold is 4.11 to 4.73 kg, and a press can be used to compress the end faces of the mold so that the distance between the two end faces is 650 to 850 mm. A certain equivalent of fragmented fibers can be compacted to a specified height, such as 650 mm, 750 mm, 850 mm, etc., by an external pressure device.

[0033] In step (3), a hollow tube is provided in the middle of the mold, and the pulp material is contained in the cavity surrounded by the mold and the hollow tube. The hollow tube is a hollow cylindrical tube, and the material is a bakelite tube, a cotton tube, a paper tube, a glass fiber tube or an aluminum tube. By setting the hollow tube, a non-woven grinding wheel with a hollow cylindrical structure and supported by the hollow tube can be obtained. The outer diameter of the hollow tube can be 35.4mm, 48.1mm, 60.8mm, 73.5mm, 86.2mm, the inner diameter is 25.4mm, 38.1mm, 50.8mm, 63.5mm, 76.2mm, and the length can be 650~900mm. The use of a hollow tube can greatly reduce the weight of the non-woven grinding wheel. The baking adopts a gradient heating method. Furthermore, the baking step includes first heating the temperature to 100-120°C in a blast oven and keeping it for 1-2 hours, then heating the temperature to 130-150°C and keeping it for 1-2 hours, and then heating the temperature to 160-180°C and keeping it for 2-4 hours. Baking by gradient heating can make the baking more complete.

[0034] In order to better illustrate the purpose, technical scheme and beneficial effects of the present invention, the present invention will be further described below in conjunction with specific embodiments. It should be noted that the following implementation method is a further explanation of the present invention and should not be used as a limitation of the present invention.

[0035] Example 1 This embodiment is a non-woven grinding wheel, the structure of which is shown in 3, and the preparation method thereof includes the following steps.

[0036] (1) Polyamide nonwoven fabric (weight 80g / m 2 ) Use a crusher to crush the fibers into fragments with a size of 1 mm.

[0037] (2) 40 parts of silicon carbide with a Dv50 of 60 μm, 20 parts of bisphenol A epoxy resin Nan Ya 128 (viscosity at 25°C is less than 20,000 cps), 10 parts of bisphenol F epoxy resin Nan Ya 170 (viscosity at 25°C is less than 20,000 cps), 7 parts of dipropylene glycol diglycidyl ether (viscosity at 25°C is less than 100 cps), 3.5 parts of dicyandiamide powder (Dv50 is 5-8 μm), 4 parts of foaming microspheres (Dv50 is 8-10 μm, initial expansion temperature is 150°C, optimal expansion temperature is 170°C), 0.5 parts of polyamide wax and 0.2 parts of 2,4,6-tris(dimethylaminomethyl)phenol were stirred in a disperser for 2 h to prepare a foaming slurry.

[0038] The foamed slurry and the fragmented fibers were simultaneously put into a kneading machine at a weight ratio of 1:1 and kneaded for 4 hours. Then, the excess slurry was compressed and squeezed out through a 1 mm wide roller device to obtain a slurry material.

[0039] (3) The pulp material is put into a hollow cylindrical mold. A hollow bakelite tube is set in the middle of the mold. The inner diameter of the bakelite tube is 76.2 mm, the outer diameter is 86.2 mm, and the length is 660 mm. 4.25 kg of pulp material is placed between the mold and the bakelite tube. The mold end panel is compressed to a height of 650 mm by a press and the end panel is fixed. It is placed in an electric hot air oven and heated to 110°C for 1 hour, then heated to 140°C for 1 hour, and then heated to 170°C for 3 hours to obtain a non-woven grinding wheel with integrated foaming of fragment fiber and abrasive.

[0040] Example 2 This embodiment is a non-woven grinding wheel, the structure of which is shown in 3, and the preparation method thereof includes the following steps.

[0041] (1) Polyamide nonwoven fabric (weight 100g / m 2 ) Use a crusher to crush the fibers into fragments with a size of 2 mm.

[0042] (2) 55 parts of silicon carbide with a Dv50 of 60 μm, 35 parts of bisphenol A epoxy resin Nan Ya 128 (viscosity at 25°C is less than 20,000 cps), 8 parts of bisphenol F epoxy resin Nan Ya 170 (viscosity at 25°C is less than 20,000 cps), 10 parts of dipropylene glycol diglycidyl ether (viscosity at 25°C is less than 100 cps), 5 parts of dicyandiamide powder (Dv50 is 5-8 μm), 7 parts of foaming microspheres (Dv50 is 8-10 μm, initial expansion temperature is 150°C, optimal expansion temperature is 170°C), 1.5 parts of polyamide wax and 0.5 parts of 2,4,6-tris(dimethylaminomethyl)phenol were stirred in a disperser for 1.5 hours to prepare a foaming slurry.

[0043] The foamed slurry and the crushed fibers were simultaneously put into a kneading machine at a weight ratio of 0.9:1 and kneaded for 3 hours. Then, the excess slurry was compressed and squeezed out through a 2 mm wide roller device to obtain a slurry material.

[0044] (3) The pulp material is put into a hollow cylindrical mold. A hollow bakelite tube is set in the middle of the mold. The inner diameter of the bakelite tube is 76.2 mm, the outer diameter is 86.2 mm, and the length is 760 mm. 4.55 kg of pulp material is placed between the mold and the bakelite tube. The mold end panel is compressed to a height of 750 mm by a press and the end panel is fixed. It is placed in an electric hot air oven and heated to 120°C for 1 hour, then heated to 130°C for 2 hours, and then heated to 180°C for 2 hours to obtain a non-woven grinding wheel with integrated foaming of fragment fiber and abrasive.

[0045] Example 3 This embodiment is a non-woven grinding wheel, the structure of which is shown in 3, and the preparation method thereof includes the following steps.

[0046] (1) Polypropylene non-woven fabric (weight 80g / m 2 ) Use a crusher to crush the fibers into fragments with a size of 1 mm.

[0047] (2) 50 parts of boron nitride with a Dv50 of 80 μm, 35 parts of bisphenol A epoxy resin Nan Ya 128 (viscosity at 25°C is less than 20,000 cps), 7 parts of 1,4-butanediol diglycidyl ether (viscosity at 25°C is less than 100 cps), 3.5 parts of BF3 amine complex powder (Dv50 is 8-10 μm), 4 parts of foaming microspheres (Dv50 is 20-23 μm, initial expansion temperature is 160°C, optimal expansion temperature is 180°C) and 0.5 parts of 2,4,6-tris(dimethylaminomethyl)phenol were stirred in a disperser for 2 h to prepare a foaming slurry.

[0048] The foamed slurry and the fragmented fibers were simultaneously put into a kneading machine at a weight ratio of 1:1 and kneaded for 4 hours. Then, the excess slurry was compressed and squeezed out through a 1 mm wide roller device to obtain a slurry material.

[0049] (3) The slurry material is put into a hollow cylindrical mold. A hollow glass fiber tube is set in the middle of the mold. The inner diameter of the glass fiber tube is 76.2 mm, the outer diameter is 86.2 mm, and the length is 660 mm. 4.25 kg of slurry material is placed between the mold and the bakelite tube. The mold end panel is compressed to a height of 650 mm by a press and the end panel is fixed. It is placed in an electric hot air oven and heated to 110°C for 2 hours, then heated to 140°C for 1 hour, and then heated to 170°C for 3 hours to obtain a non-woven grinding wheel with integrated foaming of fragment fiber and abrasive.

[0050] Comparative Example 1 This comparative example is a radial grinding wheel, whose structure is shown in 1, and its preparation method includes the following steps.

[0051] (1) Polyamide nonwoven fabric (weight 80g / m 2 ) Cut into strips of about 1 cm in size.

[0052] (2) 40 parts of silicon carbide with a Dv50 of 60 μm, 20 parts of bisphenol A epoxy resin Nan Ya 128 (viscosity at 25°C is less than 20,000 cps), 10 parts of bisphenol F epoxy resin Nan Ya 170 (viscosity at 25°C is less than 20,000 cps), 7 parts of dipropylene glycol diglycidyl ether (viscosity at 25°C is less than 100 cps), 3.5 parts of dicyandiamide powder (Dv50 is 5-8 μm), 4 parts of foaming microspheres (Dv50 is 8-10 μm, initial expansion temperature is 150°C, optimal expansion temperature is 170°C), 0.5 parts of polyamide wax and 0.2 parts of 2,4,6-tris(dimethylaminomethyl)phenol were stirred in a disperser for 2 h to prepare a foaming slurry.

[0053] The cloth strips were soaked in the foaming slurry and then adhered to the bakelite tube, the bakelite tube had an inner diameter of 76.2 mm, an outer diameter of 86.2 mm and a length of 660 mm. The cloth strips were placed in an electric hot air oven and heated to 110°C for 1 hour, then heated to 140°C for 1 hour, and then heated to 170°C for 3 hours to obtain a radial grinding wheel.

[0054] Comparative Example 2 This comparative example is a winding type grinding wheel, and its preparation method includes the following steps.

[0055] (1) 20 parts of bisphenol A epoxy resin Nan Ya 128 (viscosity at 25°C is less than 20,000 cps), 10 parts of bisphenol F epoxy resin Nan Ya 170 (viscosity at 25°C is less than 20,000 cps), 7 parts of dipropylene glycol diglycidyl ether (viscosity at 25°C is less than 100 cps), 3.5 parts of dicyandiamide powder (Dv50 is 5-8 μm), 4 parts of foaming microspheres (Dv50 is 8-10 μm, initial expansion temperature is 150°C, optimal expansion temperature is 170°C), 0.5 parts of polyamide wax and 0.2 parts of 2,4,6-tris(dimethylaminomethyl)phenol were stirred in a disperser for 2 hours to prepare a foaming slurry.

[0056] (2) Spray silicon carbide with a Dv50 of 60 μm onto a polyamide nonwoven fabric (weight 80 g / m 2 ), and then immersed in the foaming slurry, and then the polyamide non-woven fabric loaded with the foaming slurry and silicon carbide was adhered to the bakelite tube, the bakelite tube had an inner diameter of 76.2mm, an outer diameter of 86.2mm, and a length of 660mm. It was placed in an electric hot air oven and heated to 110℃ for 1h, then heated to 140℃ for 1h, and then heated to 170℃ for 3h to obtain a winding grinding wheel.

[0057] The grinding wheels prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were subjected to relevant tests, and the results are shown in Table 1. The hardness of the grinding wheel was tested using a Shore C hardness tester. A plugged resin copper clad laminate was used as a test board, a single brush grinder was used, and the test current was set to 1.5 A to test the grinding performance of the grinding wheels prepared in Examples 1 to 3 and Comparative Examples 1 to 2.

[0058] Table 1 Performance test results of grinding wheels obtained in Examples 1 to 3 and Comparative Examples 1 to 2

[0059] It can be seen from the results in Table 1 that, compared with Comparative Examples 1 and 2, the grinding wheels of Examples 1 to 3 have higher hardness and a smaller span of hardness values, indicating that the fragmented fibers in the grinding wheels of Examples 1 to 3 are evenly distributed and bonded to the foaming slurry as a whole.

[0060] The plugged resin copper-clad laminate was ground using the grinding wheels of Examples 1 to 3. The current fluctuation was small during the grinding process, and the roughness of the plate surface was lower, indicating that the abrasive interval switching was stable. In addition, the cutting force was not much different from that of the radial brush wheel. Therefore, the non-woven fabric grinding wheel prepared by the preparation method of the present invention not only has the good cutting force and elasticity of the traditional non-woven fabric grinding wheel, but also has a good plate hole edge protection effect, which can also be confirmed by the plate hole edge effect in Table 1.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it is not limited to those listed in the embodiments. Those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a non-woven grinding wheel, characterized in that: Includes steps: (1) Crushing the non-woven fabric into fragmented fibers with a size of 1 to 2 mm; (2) kneading the fiber fragments and the foamed slurry and compressing them to obtain a slurry material; (3) Placing the slurry material in a mold, compressing and fixing it, and then baking it.

2. The method for preparing a non-woven grinding wheel according to claim 1, characterized in that: The nonwoven fabric has a gram weight of 60-120 g / m 2 The non-woven fabric includes at least one of polypropylene non-woven fabric, polyester non-woven fabric and polyamide non-woven fabric.

3. The method for preparing a non-woven grinding wheel according to claim 1, characterized in that: The weight ratio of the fragment fibers to the foaming slurry is 1:0.7-1.

0.

4. The method for preparing a non-woven grinding wheel according to any one of claim 1, characterized in that: The raw materials for preparing the foaming slurry include: 40-60 parts by weight of abrasive, 20-40 parts by weight of epoxy resin, 5-15 parts by weight of epoxy diluent, 2-10 parts by weight of latent curing agent, 2-10 parts by weight of foaming microspheres and 0.5-3.0 parts by weight of auxiliary agent.

5. The method for preparing a non-woven fabric grinding wheel according to claim 4, characterized in that: The preparation method of the foaming slurry comprises: stirring a formulated amount of the abrasive, a formulated amount of the epoxy resin, a formulated amount of the epoxy diluent, a formulated amount of the latent curing agent, a formulated amount of the foaming microspheres and a formulated amount of the auxiliary agent in a disperser for 1.0 to 2.0 hours to obtain the foaming slurry.

6. The method for preparing a non-woven fabric grinding wheel according to claim 4 or 5, characterized in that: At least one of the following features ① to ⑥ is included: ① The Dv50 of the abrasive is 1-120 μm, and the abrasive includes at least one of silicon carbide, aluminum oxide, silicon dioxide and boron nitride; ② The viscosity of the epoxy resin at 25° C. is less than 20,000 cps, and the epoxy resin comprises at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and phenol novolac epoxy resin; ③ The viscosity of the epoxy diluent at 25°C is below 100 cps, and the epoxy diluent is a reactive diluent containing at least one functional group; ④ The Dv50 of the latent curing agent is less than 10 μm, and the latent curing agent includes at least one of dicyandiamide and its derivatives, organic acid hydrazides, BF3 amine complexes and imidazole compounds; ⑤ The Dv50 of the foamed microspheres is 5-50 μm, the initial expansion temperature is 140-160°C, and the optimal expansion temperature is 160-180°C; ⑥ The auxiliary agent includes at least one of a plasticizer, a diluent, a thickener, a pH adjuster, a coupling agent, a catalyst, an anti-settling agent and a pigment.

7. The method for preparing a non-woven fabric grinding wheel according to claim 1, characterized in that: At least one of the following features (i) to (v) is included: (1) the kneading is carried out in a kneader, and the kneading time is 3 to 4 hours; (ii) The compression in step (2) can be performed using a roller device with a spacing of 1 to 2 mm; (iii) the weight of the slurry material placed in the mold is 4.11-4.73 kg; (iv) The compression in step (3) may be performed by using a press to compress the end faces of the mold so that the distance between the two end faces is 650-850 mm; (V) A hollow tube is provided in the middle of the mold, and the pulp-bearing material is contained in a cavity surrounded by the mold and the hollow tube. The hollow tube includes any one of a bakelite tube, a cotton tube, a paper tube, a glass fiber tube and an aluminum tube.

8. The method for preparing a non-woven grinding wheel according to claim 1, characterized in that: The baking is carried out in a gradient temperature increasing manner.

9. The method for preparing a non-woven fabric grinding wheel according to claim 8, characterized in that: The baking step includes first heating the temperature to 100-120° C. and keeping it for 1-2 hours, then heating the temperature to 130-150° C. and keeping it for 1-2 hours, and then heating the temperature to 160-180° C. and keeping it for 2-4 hours.

10. The non-woven fabric grinding wheel prepared by the method for preparing a non-woven fabric grinding wheel according to any one of claims 1 to 9, characterized in that: The flatness of the wheel surface is less than 2mm.

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