Self-conditioning gel resin composite polishing disc for polishing optical glass and preparation method thereof

Abstract

The application discloses a self-repairing gel resin composite polishing disc for polishing optical glass and a preparation method thereof. The self-repairing gel resin composite polishing disc is prepared by using abrasive, polymer glue and fiber powder as raw materials, crushing abrasive gel, preparing abrasive gel powder, using the abrasive gel powder, thermosetting resin and fiber powder as raw materials, and foaming and curing. Traditional polishing methods for optical glass are all performed by using polyurethane polishing pads and abrasive polishing liquid, and the polishing efficiency is low; a plurality of processes are needed to polish the surface to Ra less than 5nm; meanwhile, the cost of waste liquid environmental treatment of the polishing liquid is always high, and the working environment is not environmentally friendly. The application adopts a new technical idea, and the gel body is swollen by water during the processing process, so that the elasticity is improved; meanwhile, the service life of the polishing pad is greatly enhanced, and the service life is increased by 10 times compared with the previous gel polishing pad.

Description

Technical Field

[0001] This invention pertains to polishing technology, specifically relating to a self-sharpening gel resin composite polishing disc for polishing optical glass and its preparation method. Background Technology

[0002] Optical glass is a fundamental and crucial component of the optoelectronic technology industry. As a basic material for optoelectronics, its applications in the three major fields of optical transmission, optical storage, and optoelectronic displays have seen rapid advancements, becoming one of the fundamental conditions for the development of social informatization, especially optoelectronic information technology. Optical glass differs from other types of glass in that, as a component of an optical system, it must meet the requirements of optical imaging. Therefore, its processing demands are extremely high. Optical glass, primarily composed of silicon dioxide, possesses characteristics such as high temperature resistance, low coefficient of thermal expansion, high mechanical strength, and excellent chemical properties. However, it is considered a difficult material to process. Traditional optical glass polishing methods involve using polyurethane polishing pads with abrasive polishing slurries. For example, existing technologies disclose nanodiamond aggregate / rare earth composite polishing slurries. The rare earth oxide polishing powder is preferably nano-spherical cerium oxide with an average particle size ≤30nm, prepared using a mechanochemical reaction method and a sol-gel method. The resulting polishing slurry is suitable for liquid crystal conductive glass and planar optical glass. Another example is the proposed aqueous dispersion of cerium-zirconium oxide nanomaterials. This material uses water as the dispersion medium and solid solution nanoparticles composed of cerium oxide and zirconium oxide as the dispersed phase in a sol. The nanoparticles are single crystals and can be used for optical glass polishing. Existing technologies also disclose a method for preparing ultrafine high-cerium rare earth polishing powder using a high-density rare earth carbonate high-temperature bursting method, which can improve the surface properties of materials such as optical glass, silicon wafers, and displays. Existing polishing technologies have low efficiency and require multiple processes to polish the surface to a Ra level below 5nm. At the same time, the environmental treatment cost of polishing slurry waste remains high, and the working environment is not environmentally friendly. Summary of the Invention

[0003] This invention is based on the principle of chemical flexible polishing. First, the abrasive is dispersed in a sol, and then the colloidal gel is solidified into a specific shape. After the gel is solidified, the solid containing abrasive, sol, fibers, etc. is crushed into powder of a certain diameter by a pulverizer. Then the powder is dispersed in epoxy resin, stirred evenly, and foamed to obtain a self-sharpening gel resin composite polishing disc for optical glass polishing.

[0004] The present invention adopts the following technical solution:

[0005] A method for preparing a self-sharpening gel resin composite polishing pad for optical glass polishing includes the following steps:

[0006] (1) Using abrasives, polymer adhesives and fiber powder as raw materials, prepare abrasive gel; then pulverize to prepare abrasive gel powder;

[0007] (2) Using abrasive gel powder, thermosetting resin and fiber powder as raw materials, foam and cure to prepare a self-scratching gel resin composite polishing disc for optical glass polishing.

[0008] This invention discloses a self-sharpening gel resin composite polishing disc for optical glass polishing prepared according to the above-described method for preparing a self-sharpening gel resin composite polishing disc for optical glass polishing.

[0009] This invention discloses the application of the above-mentioned self-sharpening gel resin composite polishing disc for optical glass polishing in the preparation of glass processing tools, or the application of the above-mentioned self-sharpening gel resin composite polishing disc for optical glass polishing in glass processing. Preferably, the glass is optical glass.

[0010] This invention discloses a method for processing glass using the above-mentioned self-sharpening gel resin composite polishing disc for optical glass polishing, comprising the following steps: processing glass on a polishing machine using the self-sharpening gel resin composite polishing disc for optical glass polishing to achieve glass processing.

[0011] In this invention, the abrasive is cerium oxide; the polymer is a bio-adhesive, such as xanthan gum; the fiber powder is collagen fiber powder; and the thermosetting resin is epoxy resin. As is common knowledge, thermosetting resins consist of resin raw materials and a curing agent, with a mass ratio of resin raw materials to curing agent of (1-5):1. Preferably, the diameter of the collagen fiber powder is 1-100 μm and the length is 50-500 μm; more preferably, the diameter of the collagen fiber powder is 10-80 μm and the length is 100-300 μm; and even more preferably, the diameter of the collagen fiber powder is 20-50 μm and the length is 150-250 μm.

[0012] In this invention, in step (1), the mass ratio of polymer adhesive, abrasive, and fiber powder is 1:(30-80):(10-80), preferably, the mass ratio of polymer adhesive, abrasive, and fiber powder is 1:(40-60):(20-50); more preferably, the mass ratio of polymer adhesive, abrasive, and fiber powder is 1:(45-50):(30-45).

[0013] In this invention, in step (2), the mass ratio of abrasive gel powder, thermosetting resin and fiber powder is 1:(0.5-5):(0.1-0.5), preferably, the mass ratio of abrasive gel powder, thermosetting resin and fiber powder is 1:(0.8-3):(0.1-0.4), and even more preferably, the mass ratio of abrasive gel powder, thermosetting resin and fiber powder is 1:(0.8-1.5):(0.15-0.3).

[0014] In this invention, in step (1), abrasive, polymer adhesive, fiber powder, and water are mixed, then solidified to form a gel, and then dried to obtain an abrasive gel; then pulverized to prepare abrasive gel powder, wherein the particle size of the gel powder is 1-500 μm, preferably 5-200 μm, and more preferably 50-100 μm. Preferably, metal ions are used to solidify and form the gel, such as potassium ions, calcium ions, etc.; air drying is selected.

[0015] In this invention, in step (2), the foaming and curing are carried out in a vacuum heating environment. Preferably, the vacuum degree is 0.1-1 MPa, more preferably, the vacuum degree is 0.3-0.9 MPa, and even more preferably, the vacuum degree is 0.5-0.8 MPa. The heating temperature is 50-100°C, preferably, the heating temperature is 55-90°C, and even more preferably, the heating temperature is 60-80°C. The foaming and curing time is 30-100 hours, preferably, the foaming and curing time is 40-60 hours.

[0016] Traditional optical glass polishing methods use polyurethane polishing pads and abrasive polishing slurries, resulting in low polishing efficiency and requiring multiple processes to polish the surface to a Ra below 5nm. Furthermore, the environmental treatment cost of the polishing slurry waste remains high, and the working environment is not environmentally friendly. The applicant's previously disclosed gel polishing pads (grinding wheels) improved some of the shortcomings of polyurethane polishing pads, but their lifespan was found to be short when used for processing optical glass. This invention employs a novel technical approach: dispersing abrasives in a biocolloid, such as xanthan gum, combining it with fiber powder to gel and solidify, then pulverizing it into powder of a specific size using a pulverizer, and finally dispersing and solidifying the powder in epoxy resin. The resulting polishing disc maintains the flexibility of the polishing pad; during processing, the gel swells upon contact with water, increasing elasticity. Simultaneously, the resulting polishing disc significantly enhances the lifespan of the polishing pad, increasing it tenfold compared to previous gel polishing pads.

[0017] This invention further defines the particle size of the gel abrasive powder, the size of the fiber powder, and the type of resin. By combining the ratio of these three components, a three-dimensional structure is formed during the curing process. This allows the abrasive in the polishing pad to adhere well to the mesh structure, preventing it from being buried in the resin and improving the sharpness of the polishing pad. The three-dimensional space and porous structure of the polishing pad ensure self-sharpening during processing.

[0018] This invention semi-solidifies the abrasive within a mesh polishing pad, eliminating the need for additional chemical polishing fluids during processing, thus significantly reducing costs and protecting the environment. In particular, using the polishing pad of this invention to polish optical glass can achieve a mirror-like finish in a short time, something unattainable with existing technologies. Attached Figure Description

[0019] Figure 1 This is a scanning electron microscope image of the polishing disk of the present invention;

[0020] Figure 2 Metallurgical microscope image of the cross-section of the polishing disc;

[0021] Figure 3 This is a physical image of the polishing disc of the present invention;

[0022] Figure 4 This is a cross-sectional view of the polishing disc of the present invention;

[0023] Figure 5 Schematic diagram for processing optical quartz glass;

[0024] Figure 6 Photos of the glass before and after processing;

[0025] Figure 7 This is a roughness test image after machining;

[0026] Figure 8 Scanning electron microscope (SEM) images of the glass before and after processing;

[0027] Figure 9 This is a cross-sectional view of the three polishing discs used as comparative examples.

[0028] Figure 10 This is a cross-sectional view of the actual polishing discs for comparison. Detailed Implementation

[0029] The raw materials involved in this invention are existing products, and the specific preparation operations and performance testing are conventional techniques. The collagen fibers have a diameter of 40 μm and a length of 200 μm and are from Changzhou Shuoyao Technology; the cerium oxide abrasive has a particle size of 1~4 μm; the epoxy resin is E51 bisphenol A epoxy and E51 curing agent from Nanchang Chenfang Adhesive Products Co., Ltd., with a mass ratio of epoxy to curing agent of 2:1, and the two together constitute the epoxy resin used in the experiment.

[0030] The method for preparing a self-sharpening gel resin composite polishing pad for optical glass polishing disclosed in this invention includes the following steps:

[0031] (1) Using abrasives, polymer adhesives and fiber powder as raw materials, prepare abrasive gel; then pulverize to prepare abrasive gel powder;

[0032] (2) Using abrasive gel powder, thermosetting resin and fiber powder as raw materials, foam and cure to prepare a self-scratching gel resin composite polishing disc for optical glass polishing.

[0033] This invention discloses the application of the above-mentioned self-sharpening gel resin composite polishing disc for optical glass polishing in the preparation of glass processing tools, or the application of the above-mentioned self-sharpening gel resin composite polishing disc for optical glass polishing in glass processing. Preferably, the glass is optical glass.

[0034] This invention discloses a method for processing glass using the above-mentioned self-sharpening gel resin composite polishing disc for optical glass polishing, comprising the following steps: processing glass on a polishing machine using the self-sharpening gel resin composite polishing disc for optical glass polishing to achieve glass processing.

[0035] In this invention, in step (1), the mass ratio of polymer adhesive, abrasive, and fiber powder is 1:(30-80):(10-80), preferably 1:(40-60):(20-50); more preferably, the mass ratio is 1:(45-50):(30-45). For example, 1:48:40.

[0036] In this invention, in step (2), the mass ratio of abrasive gel powder, thermosetting resin, and fiber powder is 1:(0.5-5):(0.1-0.5), preferably 1:(0.8-3):(0.1-0.4), and even more preferably 1:(0.8-1.5):(0.15-0.3). For example, 1:1:0.2.

[0037] Example 1

[0038] Add 5g xanthan gum to 500g water and stir at 800rpm for 2 hours at room temperature to prepare mixture 1;

[0039] Add 200g of collagen fiber powder and 240g of cerium oxide abrasive to 600g of water, stir at room temperature and 550rpm for 60min to prepare mixture 2;

[0040] Add mixture 2 to mixture 1 and stir at 2000 rpm for 2 hours to prepare mixture 3;

[0041] Mixture 3 was poured into a conventional mold and soaked in an aqueous solution containing 0.5 wt% calcium chloride for 10 hours; then it was removed and air-dried in a conventional manner to prepare gel fiber abrasive particle mixture 4.

[0042] Mixture 4 is crushed by a crusher, and powder with a particle size of 50-100 μm is taken as mixture 5;

[0043] Mixture 5, epoxy resin (E51 epoxy and E51 curing agent), and collagen fiber are mixed in a mass ratio of 1:1:0.2 and stirred at 800 rpm for 2 hours at room temperature to prepare mixture 6. Mixture 6 is placed in a vacuum chamber (in a conventional mold, which is common practice) and placed at a vacuum degree of 0.5 MPa and a temperature of 60°C for 48 hours to obtain a cured polishing disc. The surface is then smoothed by a grinding machine, which is a conventional technique.

[0044] Figure 1 The image above is a scanning electron microscope (SEM) image of the polishing disk. Figure 2 This is a metallographic microscope image of the cross-section of the polishing disc. Figure 3 The image shown is of the actual polishing disc mentioned above. Figure 4 This is a cross-sectional view of the polishing disc mentioned above.

[0045] Polishing pad characteristics:

[0046] 1) Polishing pad strength

[0047] Repeat the above preparation method to obtain ten polishing discs. The Shore hardness was measured and found to be 72, 71, 73, 72, 72, 73, 71, 73, 73, and 73, respectively.

[0048] 2) Polishing disc porosity

[0049] The porosity of the ten polishing disks observed under a scanning electron microscope was 81%, 85%, 83%, 80%, 85%, 80%, 83%, 80%, 82%, and 81%.

[0050] The porosity is the percentage of the area of ​​pores in a unit area when the cross-section of the polishing pad is projected.

[0051] Comparative Example 1

[0052] Add 5g xanthan gum to 500g water and stir at 800rpm for 2 hours at room temperature to prepare mixture 1;

[0053] Add 200g of collagen fiber powder and 240g of cerium oxide abrasive to 600g of water, stir at room temperature and 550rpm for 60min to prepare mixture 2;

[0054] Add mixture 2 to mixture 1 and stir at 2000 rpm for 2 hours to prepare mixture 3;

[0055] Mixture 3 was poured into a conventional mold and soaked in an aqueous solution containing 0.5 wt% calcium chloride for 10 hours; then it was removed and air-dried in a conventional manner to prepare a gel polishing pad.

[0056] Cerium oxide abrasive has high activity and cannot be prepared into a large-area polishing pad. Therefore, according to the method of Example 2 of CN113799008B, the air-dried gel block is adhered to the stainless steel substrate to form a gel polishing pad.

[0057] Comparative Example 2

[0058] A self-compensating freeze-dried polishing wheel prepared according to Example 2 of CN113799008B.

[0059] Comparative Example 3

[0060] The best-in-class polyurethane polishing pad for industrial applications combined with cerium oxide abrasive slurry.

[0061] Processing Example: Polishing Disc for Optical Glass

[0062] See Figure 5 Optical quartz glass was processed on the Shenyang Kejing UNIPOL1200S polishing machine. The upper plate speed was 60 rpm, the lower plate speed was 120 rpm, the pressure was 1.5 kg, and the time was 30 min. As is common sense, water was sprayed during the process.

[0063] Taking the polishing disc prepared by the method in Example 1 as an example, Figure 6 These are actual photos of the glass before and after processing. Figure 7 This is a roughness test image after machining. Figure 8 Scanning electron microscope (SEM) images of the glass before and after processing (scale bar: 50 μm).

[0064] The processed glass surface achieves a mirror finish with a surface roughness of 2nm, compared to 0.5μm before processing.

[0065] In comparison, under the same processing method, the surface roughness of Comparative Example 1 was 16nm after processing; Comparative Example 2 had glass scratches and was not applicable; Comparative Example 3 had a surface roughness of 32nm after processing, and after polishing for 2 hours, it reached 4nm. At this time, the abrasive consumed was much greater than that in Example 1.

[0066] The lifespan of the polishing pad can be determined by observing its wear during processing (until the tool becomes unusable); in comparison, the polishing pad prepared by the method of Example 1 has a lifespan 10 times longer than that of Comparative Example 1.

[0067] Comparative Example 4

[0068] Add 5g xanthan gum to 500g water and stir at 800rpm for 2 hours at room temperature to prepare mixture 1;

[0069] Add 200g of collagen fiber powder and 240g of cerium oxide abrasive to 600g of water, stir at room temperature and 550rpm for 60min to prepare mixture 2;

[0070] Add mixture 2 to mixture 1 and stir at 2000 rpm for 2 hours to prepare mixture 3;

[0071] Mixture 3 was poured into a conventional mold and soaked in an aqueous solution containing 0.5 wt% calcium chloride for 10 hours; then it was removed and air-dried in a conventional manner to prepare gel fiber abrasive particle mixture 4.

[0072] Mixture 4 is crushed by a crusher, and powder with a particle size of 10-30 μm is taken as mixture 5;

[0073] Mixture 5 and epoxy resin (E51 epoxy and E51 curing agent) were mixed at a mass ratio of 1:1 and stirred at 800 rpm for 2 hours at room temperature to prepare mixture 6. Mixture 6 was placed in a vacuum chamber and placed at a vacuum degree of 0.5 MPa and a temperature of 60°C for 48 hours to obtain the cured polished disc. See the cross-sectional diagram below. Figure 9 The foaming was uneven and there were unfoamed areas; no processing experiment was conducted.

[0074] Comparative Example 5

[0075] Add 5g xanthan gum to 500g water and stir at 800rpm for 2 hours at room temperature to prepare mixture 1;

[0076] Add 200g of collagen fiber powder and 240g of cerium oxide abrasive to 600g of water, stir at room temperature and 550rpm for 60min to prepare mixture 2;

[0077] Add mixture 2 to mixture 1 and stir at 2000 rpm for 2 hours to prepare mixture 3;

[0078] Mixture 3 was poured into a conventional mold and soaked in an aqueous solution containing 0.5 wt% calcium chloride for 10 hours; then it was removed and air-dried in a conventional manner to prepare gel fiber abrasive particle mixture 4.

[0079] Mixture 4 is crushed by a crusher, and powder with a particle size of 50-100 μm is taken as mixture 5;

[0080] Mixture 5, epoxy resin (E51 epoxy and E51 curing agent), and collagen fiber were mixed at a mass ratio of 1:1:0.2 and stirred at 800 rpm for 2 hours at room temperature to prepare mixture 6. Mixture 6 was placed in a forced-air drying oven and placed at 60°C for 48 hours to obtain the cured polishing disc. See the cross-sectional diagram for details. Figure 10 The foaming effect was very poor, and no processing experiment was conducted.

[0081] Example 2

[0082] Add 5g xanthan gum to 500g water and stir at 800rpm for 2 hours at room temperature to prepare mixture 1;

[0083] Add 200g of collagen fiber powder and 240g of cerium oxide abrasive to 600g of water, stir at room temperature and 550rpm for 60min to prepare mixture 2;

[0084] Add mixture 2 to mixture 1 and stir at 2000 rpm for 2 hours to prepare mixture 3;

[0085] Mixture 3 was poured into a conventional mold and soaked in an aqueous solution containing 0.5 wt% calcium chloride for 5 hours; then it was removed and air-dried in a conventional manner to prepare gel fiber abrasive particle mixture 4.

[0086] Mixture 4 is crushed by a crusher, and powder with a particle size of 50-100 μm is taken as mixture 5;

[0087] Mixture 5, epoxy resin, and collagen fiber are mixed in a mass ratio of 1:1:0.2 and stirred at 800 rpm for 2 hours at room temperature to prepare mixture 6. Mixture 6 is placed in a vacuum chamber and placed at a vacuum degree of 0.6 MPa and a temperature of 70°C for 48 hours to obtain a cured polishing disc. The surface is then smoothed by a grinding machine, which is a conventional technique.

[0088] Example 3

[0089] Add 5g xanthan gum to 500g water and stir at 800rpm for 2 hours at room temperature to prepare mixture 1;

[0090] Add 200g of collagen fiber powder and 240g of cerium oxide abrasive to 600g of water, stir at room temperature and 550rpm for 60min to prepare mixture 2;

[0091] Add mixture 2 to mixture 1 and stir at 2000 rpm for 2 hours to prepare mixture 3;

[0092] Mixture 3 was poured into a conventional mold and soaked in an aqueous solution containing 0.5 wt% calcium chloride for 20 hours; then it was removed and air-dried in a conventional manner to prepare gel fiber abrasive particle mixture 4.

[0093] Mixture 4 is crushed by a crusher, and powder with a particle size of 50-100 μm is taken as mixture 5;

[0094] Mixture 5, epoxy resin, and collagen fiber are mixed in a mass ratio of 1:1:0.2 and stirred at 800 rpm for 2 hours at room temperature to prepare mixture 6. Mixture 6 is placed in a vacuum chamber and placed at a vacuum degree of 0.5 MPa and a temperature of 65°C for 48 hours to obtain a cured polishing disc. The surface is then smoothed by a grinding machine, which is a conventional technique.

[0095] During processing, the abrasive undergoes sol-gel treatment, resulting in a certain degree of inclusion effect, which is a form of flexible polishing that achieves extremely high surface quality. Simultaneously, by controlling the resin curing temperature and environmental pressure, and by adjusting the three-dimensional space formed between the resin, abrasive, and fibers through different ratios, a uniformly porous polishing disc can be foamed. The abrasive can then adhere well within the pores (see...). Figure 1 This material exhibits excellent cutting and removal capabilities during processing. Furthermore, the abrasive is semi-solidified within the polishing pad, eliminating the need for additional chemical polishing fluids, significantly reducing costs and protecting the environment. Simultaneously, due to its mesh-like porous structure (see gel resin polishing pad), it also... Figure 2This increases the self-cleaning ability of the polishing pad, eliminating the need for trimming during processing. The abrasive particles are exposed layer by layer as the fibers fall off, ensuring the sharpness of the polishing pad.

[0096] Optical glass, with silicon dioxide as its main component, has the characteristics of high temperature resistance, low coefficient of expansion, high mechanical strength, and good chemical properties. However, it is a difficult material to process. In current production, optical glass is polished using polyurethane polishing pads and cerium oxide abrasive polishing slurry. This method has low polishing efficiency and requires multiple processing steps to polish the surface to Ra below 5nm. At the same time, the environmental treatment cost of the waste liquid from polishing slurry remains high, and the working environment is not environmentally friendly.

[0097] This invention adopts a novel technical approach, and the polishing pad prepared is used for polishing optical glass. In one process (30 minutes), the surface can be polished to Ra below 5nm, and no polishing liquid is required, making the working environment environmentally friendly.

Claims

1. A method for preparing a self-sharpening gel resin composite polishing disc for optical glass polishing, characterized in that, Includes the following steps: (1) Using abrasives, polymer adhesives and fiber powder as raw materials, prepare abrasive gel; then pulverize to prepare abrasive gel powder; (2) Using abrasive gel powder, thermosetting resin and fiber powder as raw materials, foaming and curing are carried out to prepare a self-sharpening gel resin composite polishing disc for optical glass polishing; foaming and curing are carried out in a vacuum heating environment; The abrasive is cerium oxide; the polymer is a bio-adhesive; the fiber powder is collagen fiber powder; the thermosetting resin is epoxy resin. In step (1), the mass ratio of polymer adhesive, abrasive, and fiber powder is 1:(30-80):(10-80); In step (2), the mass ratio of abrasive gel powder, thermosetting resin and fiber powder is 1: (0.5~5): (0.1~0.5).

2. The method for preparing the self-sharpening gel resin composite polishing disc for optical glass polishing according to claim 1, characterized in that, The mass ratio of polymer adhesive, abrasive, and fiber powder is 1:(40-60):(20-50); the mass ratio of abrasive gel powder, thermosetting resin, and fiber powder is 1:(0.8-3):(0.1-0.4).

3. The method for preparing the self-sharpening gel resin composite polishing disc for optical glass polishing according to claim 1, characterized in that, In step (1), abrasive, polymer glue, fiber powder and water are mixed, then solidified to form a gel, and then dried to obtain abrasive gel; then crushed to prepare abrasive gel powder, wherein the particle size of the gel powder is 1 to 500 μm.

4. The method for preparing the self-sharpening gel resin composite polishing disc for optical glass polishing according to claim 1, characterized in that, The vacuum degree is 0.1-1 MPa; the heating temperature is 50-100℃; and the foaming and curing time is 30-100 hours.

5. The self-sharpening gel resin composite polishing disc for optical glass polishing prepared by the method described in claim 1.

6. A method for processing glass using the self-sharpening gel resin composite polishing disc for optical glass polishing as described in claim 5, characterized in that, The process includes the following steps: processing glass on a polishing machine using a self-sharpening gel resin composite polishing disc for optical glass polishing.

7. The application of the self-sharpening gel resin composite polishing disc for optical glass polishing as described in claim 5 in the preparation of glass processing tools, or in the processing of glass.

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