A method for cleaning a glass-ceramic

Abstract

The application discloses a kind of microcrystalline glass cleaning methods, belong to microcrystalline glass technical field.The scheme is washed by alkaline cleaning agent to obtain higher surface cleanliness to microcrystalline glass cover plate, then the plating surface of the microcrystalline glass cover plate after washing is applied to the pre-plating layer with strong alkali resistance, then the pre-plating layer of microcrystalline glass cover plate is polished by mill, and only the pre-plating layer of partial thickness is reserved after polishing, so that the microcrystalline glass cover plate after polishing has better surface roughness, finally, the remaining polishing abrasive is washed away with alkaline cleaning agent, and the microcrystalline glass with good cleanliness and surface roughness can be obtained, so as to improve the adhesion of film layer and ink coating, and improve the dirtiness of microcrystalline glass surface, pad color difference, plating color difference, film layer peeling and other defects.

Description

Technical Field

[0001] This invention relates to the field of glass-ceramic technology, and more particularly to a method for cleaning glass-ceramic. Background Technology

[0002] Currently, microcrystalline glass is increasingly used in glass covers for mobile phones, smart wearable devices, automotive applications, and smart homes. However, microcrystalline glass covers are generally not resistant to alkaline cleaning agents. After cleaning with alkaline cleaning agents, the surface roughness of microcrystalline glass covers increases. When microcrystalline glass covers need to be coated with anti-fingerprint films, AR films, or ink, the higher surface roughness leads to poor adhesion of the film or ink coating, easily causing the film or ink coating to peel off or result in discoloration.

[0003] Existing cleaning solutions typically use neutral cleaning agents, but these agents are less effective. Microcrystalline glass covers often have residual dirt after being cleaned with neutral cleaning agents, resulting in poor cleanliness and various defects such as color discrepancies in pad printing, coatings, surface dirt, and film peeling. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a microcrystalline glass cleaning method to address the above-mentioned deficiencies of the prior art. After cleaning the microcrystalline glass using the method, it can maintain good cleanliness and surface roughness, and reduce various adverse phenomena in the subsequent coating or printing process.

[0005] To achieve the above objectives, the present invention provides a method for cleaning microcrystalline glass, the method comprising the following steps:

[0006] Step S1: Clean the strengthened microcrystalline glass with an alkaline cleaning agent;

[0007] Step S2: Apply a pre-coating layer with strong alkali resistance to the coated surface of the cleaned microcrystalline glass, the pre-coating layer having a first thickness.

[0008] Step S3: The pre-coating layer of the microcrystalline glass is subjected to mill polishing. After polishing, the pre-coating layer has a second thickness, which is less than the first thickness.

[0009] Step S4: Clean the polished microcrystalline glass with the alkaline cleaning agent described in step S1.

[0010] Preferably, the first thickness is determined based on the surface roughness of the microcrystalline glass after cleaning with an alkaline cleaning agent.

[0011] Preferably, the pre-plating layer comprises one or more materials selected from silicon dioxide, silicon oxynitride, and silicon carbide.

[0012] Preferably, the second thickness is ≥2nm.

[0013] Preferably, the alkaline cleaning agent has a pH ≥ 10, and the alkaline cleaning agent comprises a strong alkali and a complexing agent.

[0014] Preferably, the strong alkali is either potassium hydroxide or sodium hydroxide, or a mixture of the two.

[0015] Preferably, the complexing agent is sodium gluconate.

[0016] Preferably, the method of applying the pre-coating includes vapor deposition, sputtering, and spraying.

[0017] Preferably, in step S3, the polishing powder used for polishing is a fine polishing powder with a particle size ≤0.6μm, and the brush is a polyurethane sponge brush.

[0018] The present invention involves cleaning a microcrystalline glass cover plate with an alkaline cleaning agent to achieve a high surface cleanliness. A pre-coating layer with strong alkali resistance is then applied to the coated surface of the cleaned microcrystalline glass cover plate. This pre-coating layer is then machine-polished, leaving only a portion of the pre-coating layer after polishing. This results in a microcrystalline glass cover plate with good surface roughness. Finally, residual polishing abrasive is removed with an alkaline cleaning agent, thus producing microcrystalline glass with excellent cleanliness and surface roughness. This improves the adhesion between the film layer and the ink coating, and mitigates defects such as surface dirt, color discrepancies in pad printing, color discrepancies in coating, and film peeling on the microcrystalline glass. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0020] Figure 1 This is a schematic diagram of the steps of a microcrystalline glass cleaning method provided in an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The general idea of ​​this invention is as follows: a microcrystalline glass cover is cleaned with an alkaline cleaning agent to obtain a high surface cleanliness. Then, a pre-coating layer with strong alkali resistance is applied to the coated surface of the cleaned microcrystalline glass cover. The pre-coating layer of the microcrystalline glass cover is then polished by a grinding machine. After polishing, only a portion of the pre-coating layer is retained, so that the polished microcrystalline glass cover has a good surface roughness. Finally, the residual polishing abrasive is washed away with an alkaline cleaning agent, thus obtaining microcrystalline glass with good cleanliness and surface roughness.

[0023] The embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. It should be understood that the embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0024] This invention is applicable to the cleaning of reinforced microcrystalline glass.

[0025] like Figure 1 As shown, this embodiment of the invention provides a method for cleaning microcrystalline glass, the method comprising the following steps:

[0026] Step S1: Clean the strengthened microcrystalline glass with an alkaline cleaning agent.

[0027] In the prior art, microcrystalline glass substrates are usually prepared through CNC machining, mill polishing, and strengthening processes. For 3D microcrystalline glass covers, hot bending is required before mill polishing. The solution of the present invention is applicable to the processing of strengthened microcrystalline glass.

[0028] This invention does not particularly limit the type of alkaline cleaning agent. In some embodiments of this invention, the pH of the alkaline cleaning agent is ≥10, and the components of the alkaline cleaning agent include a strong alkali and a complexing agent. The strong alkali can chemically react with the dirt components on the surface of the glass-ceramic and the glass-ceramic substrate, causing the dirt components to detach and achieving the purpose of cleaning. The greater the amount of strong alkali used, the stronger the cleaning ability, but the stronger the corrosiveness to the glass-ceramic substrate. The complexing agent is also an important component of glass cleaning agents. Complexing agents play multiple roles in glass cleaning agents, such as softening water quality, enhancing cleaning effect, preventing secondary pollution, protecting sensitive surfaces, and improving the stability of the cleaning solution. They are an indispensable component for optimizing glass cleaning performance.

[0029] The strong base is either potassium hydroxide or sodium hydroxide, or a mixture thereof, and the complexing agent is sodium gluconate or other common complexing agent components.

[0030] This invention does not impose any particular restrictions on the cleaning methods and equipment for microcrystalline glass. Depending on the size of the microcrystalline glass itself and the actual production conditions, a flatbed cleaning machine or an ultrasonic cleaning machine can be selected for cleaning.

[0031] This invention does not impose any particular limitation on the concentration of the alkaline cleaning agent. In some embodiments of this invention, the alkaline cleaning agent is diluted with pure water to a ratio of 1:10 to 1:50 before use. The lower the concentration of the alkaline cleaning agent, the weaker its cleaning ability; the higher the concentration, the stronger its cleaning ability, but also the more severe the corrosion of the glass-ceramic, resulting in a higher surface roughness after cleaning. In this embodiment of the invention, the cleaning is considered complete when there is no visible dirt on the surface of the glass-ceramic. Before cleaning, the surface roughness Ra of the glass-ceramic is ≤0.6 nm; after cleaning, the surface roughness Ra of the glass-ceramic is ≥0.8 nm. Compared to using a neutral cleaning agent, using an alkaline cleaning agent can achieve better cleanliness; however, it also increases the surface roughness of the glass-ceramic, requiring subsequent surface treatment to obtain a better surface roughness.

[0032] Step S2: Apply a pre-coating layer with strong alkali resistance to the coated surface of the cleaned microcrystalline glass, the pre-coating layer having a first thickness.

[0033] The coated surface refers to the surface of the microcrystalline glass that needs to be coated or printed later. In practical applications, coating or printing is usually only performed on part of the microcrystalline glass, such as coating or printing only on the top surface, or coating or printing on the top surface and the side surface at the same time.

[0034] The pre-plating layer is made of a material with strong alkali resistance. In this embodiment of the invention, the pre-plating layer includes one or more of the following materials: silicon dioxide, silicon oxynitride, and silicon carbide.

[0035] This invention does not impose any particular limitation on the coating method of the pre-coating layer. In embodiments of this invention, the method of applying the pre-coating layer includes vapor deposition, sputtering, and spraying.

[0036] After cleaning with an alkaline cleaning agent, the dirt on the surface of the microcrystalline glass is removed. Simultaneously, the alkaline cleaning agent reacts chemically with the microcrystalline glass surface, creating tiny grooves. These grooves make the surface rougher, resulting in an increased roughness value. In practical applications, the roughness value of the microcrystalline glass surface can be measured using specialized instruments. The pre-coating layer is a thin film of uniform thickness covering the surface of the microcrystalline glass. After the pre-coating layer is applied to the coated surface of the microcrystalline glass, the grooves on the surface are filled by the pre-coating layer, making the grooves shallower, while the areas on the microcrystalline glass surface without grooves become thicker due to the pre-coating layer.

[0037] In the pre-coating stage, random sampling of the glass-ceramic can be performed. By comparing the B-value and visible light transmittance of the glass-ceramic before and after pre-coating, it can be determined whether the effect of the pre-coating layer on the B-value and visible light transmittance of the glass-ceramic meets expectations, thereby determining whether the equipment parameters are set correctly. Theoretically, the applied coating layer can improve the B-value and visible light transmittance of the glass-ceramic.

[0038] Step S3: The pre-coating layer of the microcrystalline glass is subjected to mill polishing. After polishing, the pre-coating layer has a second thickness, which is less than the first thickness.

[0039] The pre-coating layer flattens the grooves on the surface of the glass-ceramic as much as possible. Then, the pre-coating layer is polished to remove the excess thickness, leaving only a small amount for the subsequent cleaning step S4. Because the grooves on the surface of the glass-ceramic are shallower, the thicker areas of the surface are thinned during polishing, resulting in a significant improvement in the surface roughness of the glass-ceramic.

[0040] In this embodiment of the invention, the amount of material removed is monitored by monitoring the B-value and visible light transmittance. After applying a pre-coating to the surface of the glass-ceramic, both the B-value and visible light transmittance of the glass-ceramic increase. During the polishing process, as the pre-coating continues to thin, the B-value and visible light transmittance of the glass-ceramic continuously change. When the B-value and visible light transmittance are very close to their values ​​before the application of the pre-coating, the thickness of the pre-coating is close to zero. In this embodiment of the invention, a second thickness is maintained for the pre-coating, which is ≥2nm. Because the pre-coating is made of a material with strong alkali resistance, maintaining a certain thickness can protect the glass-ceramic substrate during subsequent alkaline washing. From a cost perspective, the larger the first thickness of the pre-coating, the lower the cost. However, while retaining a portion of the pre-coating can improve the visible light transmittance of the glass-ceramic, if the second thickness is too large, in addition to increasing costs, it will also affect the parameter design of subsequent processes such as AR coating on the glass-ceramic. In practical applications, if it is necessary to increase the visible light transmittance of glass-ceramics by increasing the second thickness of the pre-coating layer, the design parameters of subsequent processes need to be adjusted according to the second thickness of the pre-coating layer.

[0041] The process for determining the first thickness of the pre-coating layer is as follows:

[0042] (1) After the cleaning step S1, the roughness, B-value, and visible light transmittance of the microcrystalline glass are measured and denoted as first roughness, first B-value, and first visible light transmittance, respectively. The first visible light transmittance can be selected as the transmittance of a fixed wavelength or multiple fixed wavelengths. A thinner pre-coating significantly improves the transmittance of visible light in smaller wavelength bands, while a thicker pre-coating significantly improves the transmittance of both smaller and larger wavelength bands of visible light. In some embodiments of the present invention, several fixed wavelengths in smaller wavelength bands are selected for visible light transmittance measurement.

[0043] (2) The first removal amount in the polishing process is preset according to the roughness;

[0044] (3) Determine the first thickness of the pre-coated film based on the first removal amount, the first thickness = the first removal amount + the second thickness, and apply the pre-coated film of the first thickness to the microcrystalline glass;

[0045] (4) Polish the pre-plated microcrystalline glass. The amount of polishing is the first amount of polishing. Measure the roughness of the microcrystalline glass after the first amount of polishing is completed as the second roughness. If the second roughness is greater than the first roughness, increase the first amount of polishing and jump to step (3) to re-plat the microcrystalline glass. Repeat the test until the second roughness is approximately equal to the first roughness, and the difference between the polished B value and the first B value is within an acceptable range. The difference between the polished visible light transmittance and the first visible light transmittance is also within an acceptable range. Thus, determine the appropriate first amount of polishing and the first thickness value.

[0046] In this embodiment of the invention, the first thickness is 5nm-200nm. The higher the surface roughness value of the microcrystalline glass after cleaning with alkaline cleaning agent, the greater the first thickness value of the pre-coated layer.

[0047] In this embodiment of the invention, the polishing powder used for polishing is a fine polishing powder with a particle size ≤0.6μm, and the brush is a polyurethane sponge brush.

[0048] In this embodiment of the invention, the amount of material removed by polishing is controlled by controlling the polishing time, polishing pressure, polishing speed, and grinding powder concentration. This invention does not impose any particular limitations on the polishing time, polishing pressure, polishing speed, and grinding powder concentration. Specifically, in some embodiments of this invention, the polishing time is 800-1000 seconds, the polishing pressure is 40-80 kg, the polishing speed is 20-30 r / min, and the grinding powder concentration is 10-12 units.

[0049] Step S4: Clean the polished microcrystalline glass with the alkaline cleaning agent described in step S1.

[0050] After polishing in step S3, the surface roughness of the resulting microcrystalline glass is reduced. However, polishing powder remains on the surface. Neutral cleaning agents have limited cleaning ability for this polishing powder. In this embodiment, the alkaline cleaning agent described in step S1 is used to clean the polished microcrystalline glass to remove the polishing powder from its surface. During polishing, a pre-coating layer of a certain thickness is left on the coated surface. This pre-coating layer has strong alkali resistance. During cleaning with the alkaline cleaning agent, the surface of the pre-coating layer is uniformly thinned, without creating an uneven structure, and thus has no impact on the surface roughness of the microcrystalline glass.

[0051] After cleaning in step S4, a microcrystalline glass with good cleanliness and roughness is obtained. At this point, the probability of product defects during anti-fingerprint coating or ink printing is significantly reduced. Compared to cleaning methods using neutral cleaning agents, the microcrystalline glass cleaning method of this invention reduces the defect rate of mismatched colors in pad printing from 12% to 0.20%, the defect rate of mismatched colors in coating from 18% to 0.50%, the defect rate of surface contamination from 30% to 1.02%, and the defect rate of film peeling from 5% to 0.10%.

[0052] The present invention involves cleaning a microcrystalline glass cover plate with an alkaline cleaning agent to achieve a high surface cleanliness. A pre-coating layer with strong alkali resistance is then applied to the coated surface of the cleaned microcrystalline glass cover plate. This pre-coating layer is then machine-polished, leaving only a portion of the pre-coating layer after polishing. This results in a microcrystalline glass cover plate with good surface roughness. Finally, residual polishing abrasive is removed with an alkaline cleaning agent, thus producing microcrystalline glass with excellent cleanliness and surface roughness. This improves the adhesion between the film layer and the ink coating, and mitigates defects such as surface dirt, color discrepancies in pad printing, color discrepancies in coating, and film peeling on the microcrystalline glass.

[0053] The above are merely specific embodiments of the present invention and should not be construed as limiting the scope of the present invention. Equivalent variations made by those skilled in the art based on this invention, as well as changes well-known to those skilled in the art, should still fall within the scope of the present invention.

Claims

1. A method for cleaning microcrystalline glass, characterized in that, The method includes the following steps: Step S1: Clean the strengthened microcrystalline glass with an alkaline cleaning agent; Step S2: Apply a pre-coating layer with strong alkali resistance to the coated surface of the cleaned microcrystalline glass, the pre-coating layer having a first thickness. Step S3: The pre-coating layer of the microcrystalline glass is subjected to mill polishing. After polishing, the pre-coating layer has a second thickness, which is less than the first thickness. Step S4: Clean the polished microcrystalline glass with the alkaline cleaning agent described in step S1.

2. The microcrystalline glass cleaning method according to claim 1, characterized in that, The first thickness is determined based on the surface roughness of the microcrystalline glass after cleaning with an alkaline cleaning agent.

3. The microcrystalline glass cleaning method according to claim 1, characterized in that, The pre-plating layer includes one or more materials selected from silicon dioxide, silicon oxynitride, and silicon carbide.

4. The microcrystalline glass cleaning method according to claim 1, characterized in that, The second thickness is ≥2nm.

5. The microcrystalline glass cleaning method according to claim 1, characterized in that, The alkaline cleaning agent has a pH ≥ 10, and its components include a strong alkali and a complexing agent.

6. The microcrystalline glass cleaning method according to claim 5, characterized in that, The strong base is either potassium hydroxide or sodium hydroxide, or a mixture of the two.

7. The microcrystalline glass cleaning method according to claim 5, characterized in that, The complexing agent is sodium gluconate.

8. The microcrystalline glass cleaning method according to claim 1, characterized in that, The methods for applying the pre-coating include vapor deposition, sputtering, and spraying.

9. The microcrystalline glass cleaning method according to claim 1, characterized in that, In step S3, the polishing powder used for polishing is a fine polishing powder with a particle size ≤0.6μm, and the brush is a polyurethane sponge brush.

Images