A dry forming method of super-thick peep window anti-nuclear radiation laminated glass

Abstract

This invention relates to a dry forming method for ultra-thick, radiation-resistant, and nuclear-proof laminated glass for viewing windows. The method includes the following steps: cleaning and drying a glass plate, then applying a protective electrostatic film to the non-adhesive surface; cutting a polymer resin film to a size matching the glass plate and conditioning it in a clean space; laying the polymer resin film on the surface of the glass plate to be bonded, and then using a laminating machine to stack the glass plate to be bonded on top of the glass plate with the adhesive film laid; vacuum-exhausting the laminated glass plate until there are no bubbles or impurities, and the transparency is 60-80%; subjecting the glass plate to high-temperature and high-pressure composite curing, followed by post-treatment, to complete the dry forming of ultra-thick, radiation-resistant, and nuclear-proof laminated glass for viewing windows. Compared with existing technologies, this invention has advantages such as enabling industrial-scale mass production without requiring large-scale new investment, high heating efficiency, uniform temperature field in the laminated glass, and low internal stress.

Description

Technical Field

[0001] This invention relates to the field of nuclear industry viewing glass plates, specifically to a dry forming method for ultra-thick viewing window anti-nuclear radiation resistant laminated glass. Background Technology

[0002] Nuclear energy, as a clean, efficient, and high-quality energy source, has been applied in more than 30 countries worldwide. The single piece of radiation-resistant glass used in viewing window designs typically exceeds 230 mm, with some reaching over 400 mm. Currently, the thickest glass plate produced by Germany's SCHOTT company is 420 mm, by the US company CORNING 400 mm, and by France's LEMER PAX using "Safety Laminated Lead Glass Block (SLLGB)" technology to achieve unlimited thickness, with their thickest glass plate reaching 570 mm. Learning from LEMER PAX's SLLGB technology is an effective way to address the current bottleneck in the thickness of radiation-resistant glass plates in China; this involves combining glass plates of different thicknesses into a single piece of glass that meets the design thickness using one or more layers of interlayer film. According to the official website of the French company LEMERPAX, laminated radiation-resistant glass panels have the following advantages: ① Excellent impact resistance: When the glass panel is impacted, the single-layer glass breaks, but because the adhesive layer prevents crack propagation, penetrating cracks along the thickness direction will not occur, thus preventing the leakage of nuclear radiation; ② No thickness limitations, allowing for greater design flexibility for viewing windows; ③ Protective layers (such as PMMA optical glass) can be laminated onto the inner and outer surfaces of the glass panel, eliminating the need for additional protective glass during viewing window assembly. This reduces optical loss, and because the protective layer and the glass panel are bonded together as a whole, there is no condensation problem. However, the technical details of the company's SLLGB technology (including adhesive layer material, optical thickness, molding process, etc.) are completely unknown, and there are no public reports on it.

[0003] The technology of general-purpose glass lamination is very mature, and a large number of patents have been published on the processing technology and preparation methods of laminated glass, such as CN108840582A, CN110183118A, CN112571910A, and CN112497886A. However, these processes and methods are all for thin glass lamination in the transportation and construction fields, and are applicable to resins such as PVB, EVA, SGP, PMMA, and PU. They are not applicable to radiation-resistant glass sheets with a single layer thickness of more than 230 mm, or composites of special polymer resins that are resistant to nuclear radiation. Compared to thin glass lamination, the lamination process for ultra-thick radiation-resistant glass sheets presents the following unique challenges: First, the glass sheets are both thick and heavy, making it difficult to expel air bubbles from the adhesive layer after lamination. Second, the glass sheets have slow heat conduction, resulting in uneven heating of the adhesive layer and a tendency to generate internal stress. Third, the melting temperature of special polymer resins is much higher than that of resins such as PVB and EVA, with a difference exceeding 100°C. This higher lamination molding temperature causes the evaporation of moisture and small molecules within the adhesive layer, leading to the formation of air bubbles. Fourth, controlling the optical thickness and tolerances of the lamination during the molding process presents significant challenges. Summary of the Invention

[0004] The purpose of this invention is to overcome at least one of the defects of the prior art and provide a dry forming method for ultra-thick peep window anti-nuclear radiation resistant laminated glass that can be industrialized and mass-produced without the need for additional large-scale investment, has high heating efficiency, uniform temperature field of laminated glass, and low internal stress.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A dry forming method for ultra-thick, radiation-resistant, and nuclear-proof laminated glass for viewing windows, comprising the following steps:

[0007] Glass plate pretreatment: After cleaning and air-drying the glass plate, a protective electrostatic film is applied to the non-adhesive surface. A moderately strong electrostatic film is used to protect the non-adhesive surface of the glass plate, preventing damage to the optical interface during operation. Radiation-proof or radiation-resistant glass materials must meet the technical requirements stipulated by the national or nuclear power / nuclear industry design institutes. Typical domestically produced radiation-proof glass materials include ZF6, ZF7, and ZF501; typical domestically produced radiation-resistant glass materials include K509 and K709.

[0008] Polymer resin film cutting and conditioning: Cut the polymer resin film to the size that matches the glass plate and condition it in a clean space; the polymer resin is polyaryletherketone (PAEK) or thermoplastic polyimide (TPI) resin transparent optical film.

[0009] Adhesive film laying, trimming and lamination: The polymer resin adhesive film is laid on the surface of the glass plate to be bonded, and then the glass plate to be bonded is stacked on top of the glass plate with adhesive film laid.

[0010] Vacuum degassing and pre-compression: The assembled glass plate is subjected to vacuum degassing until there are no bubbles or impurities and the transparency is 60-80%;

[0011] High-temperature and high-pressure composite curing and post-treatment: The glass plate is subjected to high-temperature and high-pressure composite curing, followed by post-treatment, to complete the dry forming of ultra-thick peep window anti-nuclear radiation resistant laminated glass. The above forming method is also applicable to the lamination of 3 layers or more of anti-nuclear radiation resistant glass, and is also applicable to different types of glass lamination, which can be selected according to the design requirements of the peep window.

[0012] Furthermore, the specific steps for cleaning the glass plate are as follows: the glass plate is cleaned in three stages. The first and second stages use tap water heated to 40-60℃, and the third stage uses deionized water or reverse osmosis water to remove salt from the tap water. The resistivity of the deionized water or reverse osmosis water is >10 MΩ or the conductivity is <10 μs.

[0013] Furthermore, the air-drying temperature is 120-150℃.

[0014] Furthermore, the length and width dimensions of the polymer resin film are 5-6 mm larger than those of the glass plate bonding surface. To eliminate contamination of the film by impurities in the working environment, this process must be carried out in a cleanroom of Class 100,000 or higher, and operators must wear protective clothing and disposable silicone gloves throughout the process.

[0015] Furthermore, the environmental parameters for conditioning are: moisture content ≤0.2%, ambient temperature 23-25℃, humidity 25-30%, and conditioning time not less than 24 hours.

[0016] Furthermore, during installation, low-tack tape is applied along the excess edges. After lamination, the low-tack tape is removed. Because the adhesive film has a certain rigidity, it is prone to shifting during production line movement. Therefore, low-tack tape is used to secure the film to the side of the glass plate along the excess edges. Note that the tape should not extend into the interlocking area to prevent it from being pressed and unable to be removed during lamination.

[0017] Furthermore, the vacuum degassing and pre-pressurization process employs a two-stage preheating vacuum exhaust system. In the first stage, the furnace temperature is 90-140℃, the vacuum degree is ≤0.08 MPa, and the holding time is 60-90 min. In the second stage, the furnace temperature is 180-240℃, the vacuum degree is ≤0.08 MPa, and the holding time is 90-140 min.

[0018] Furthermore, the high-temperature and high-pressure composite curing process employs six stages, with the specific process parameters as follows: The first stage is heating and pressurizing, where the temperature rises from room temperature to 60-80℃ and the pressure rises from atmospheric pressure to 0.6-0.8 MPa, then held for 60-90 minutes; the second stage is holding and heating, where the pressure remains constant and the temperature rises from 80℃ to 300-360℃, then held for 180-240 minutes; the third stage is isothermal and pressurizing, where the temperature remains constant and the pressure rises to 1.2-2.0 MPa, then held for 30-60 minutes; the fourth stage is isothermal and isothermal, where the temperature and pressure remain constant for 60-90 minutes; the fifth stage is isothermal and cooling, where the pressure remains constant and the temperature slowly decreases to 40℃, a process that takes 360-480 minutes; the sixth stage is venting, where when the temperature is below 40℃, venting is performed until the pressure reaches 0.03-0.05 MPa, the temperature drops to room temperature, then held for 60-90 minutes; finally, venting is performed back to atmospheric pressure.

[0019] Furthermore, the heating method is microwave heating.

[0020] Furthermore, the post-processing includes cutting, polishing, coating, protection, or packaging.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] (1) This invention can effectively solve the bottleneck that the thickness of current radiation-resistant glass plates in China cannot meet the design requirements of viewing windows for nuclear power plants or other nuclear industries. It further improves the overall localization rate of third-generation domestically produced nuclear power, reduces procurement costs and time, and solves the problem of domestic self-sufficiency and controllability of key materials;

[0023] (2) This invention can be modified on the basis of existing transportation and building laminated glass production lines to achieve industrialized mass production without the need for new large-scale investment;

[0024] (3) The vacuum degassing pre-pressurization and high pressure vessel of the present invention adopt microwave heating, which has high heating efficiency, uniform temperature field of laminated glass and low internal stress. Attached Figure Description

[0025] Figure 1 This is a flowchart of the molding process of the present invention;

[0026] Figure 2 This is a comparison diagram of the white light transmittance of the glass before and after irradiation in the embodiment. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0028] A dry forming method for ultra-thick, radiation-resistant laminated glass for peep windows is disclosed. This method is also applicable to the lamination of three or more layers of radiation-resistant glass and is suitable for different types of glass lamination, allowing selection based on the peep window design requirements. The method includes the following steps: Figure 1 As shown:

[0029] (1) Glass Plate Cleaning: Glass plates that have passed the incoming inspection are transferred to a multi-functional cleaning and drying machine. They undergo three cleaning stages. The first and second stages use ordinary tap water heated to 40-60℃, plus water overflowing from subsequent cleaning stages. The third stage uses a deionization system or reverse osmosis system to remove salt from the tap water. The water resistivity must be >10 MΩ or the conductivity <10 µs. Radiation-resistant or nuclear-proof glass materials must meet the technical requirements stipulated by the state or nuclear power / nuclear industry design institutes. Typical domestic radiation-resistant glass materials include ZF6, ZF7, and ZF501; typical domestic nuclear-proof glass materials include K509 and K709.

[0030] (2) Transfer the cleaned glass plate to the air drying section for hot air circulation drying at a temperature of 120-150℃.

[0031] (3) Protection of non-adhesive surfaces of glass plates: Use an electrostatic film of moderate strength to protect the non-adhesive surfaces of glass plates to prevent damage to the optical interface of glass plates during operation.

[0032] (4) Cutting of special polymer resin film: The film is cut using a CNC laser cutting machine. The length and width of the film are slightly larger than the length and width of the glass plate bonding surface by 5-6 mm. To eliminate contamination of the film by impurities in the working environment, this process must be carried out in a clean room of Class 100,000 or above. The operators must wear protective clothing and disposable silicone gloves throughout the process. The special polymer resin for nuclear radiation resistance is polyaryletherketone (PAEK) or thermoplastic polyimide (TPI) resin transparent optical film.

[0033] (5) Conditioning of special polymer resin film: The cut film is placed in a constant temperature and humidity room in a clean workshop for conditioning for more than 24 hours to make its moisture content ≤0.2%. The ambient temperature of the constant temperature and humidity room is 23-25℃ and the humidity is 25-30%.

[0034] (6) Adhesive film laying and trimming: Lay the properly prepared adhesive film in the center on the surface of the glass plate to be bonded, with the edge of the adhesive film being 5-6 mm larger than the length and width of the glass plate. Since the adhesive film has a certain rigidity, it is easy to shift when it flows on the production line. Therefore, it is necessary to use low-tack tape to fix the adhesive film to the side of the glass plate along the excess part of the edge. Note that the tape should not extend into the bonding area to prevent it from being pressed and unable to be torn off when the sheets are joined. This process must be carried out in a constant temperature and humidity room in a clean workshop. The temperature and humidity requirements are the same as those in process (5).

[0035] (7) Assembly: The glass plates with the adhesive film laid and the glass plates to be bonded are transferred to the assembly process along the production line. The glass plates to be bonded are stacked on top of the glass plates with the adhesive film laid using an assembly machine, requiring that the four sides of the upper and lower glass plates be flush. After assembly, the adhesive tape pasted on the sides of the adhesive film and lead glass in the previous process is removed. This process must be carried out in a constant temperature and humidity room in a cleanroom, and the temperature and humidity requirements are the same as those in process (5).

[0036] (8) Vacuuming and pre-pressing: The laminated glass plates are neatly placed on the operating table of the glass laminating furnace and covered with a vacuum silicone bag. To improve heating efficiency and ensure heating uniformity, the traditional infrared heating method is replaced with microwave heating. Two-stage preheating and vacuuming are used: the first stage has a furnace temperature of 90-140℃, a vacuum degree of ≤0.08 MPa, and a holding time of 60-90 min; the second stage has a furnace temperature of 180-240℃, a vacuum degree of ≤0.08 MPa, and a holding time of 90-140 min. After completion, the vacuum is unloaded after the glass plates are naturally cooled to room temperature in the laminating furnace. After cooling, the edge sealing integrity and the quality of the laminating layer are checked, requiring no bubbles, no impurities, and a transparency of 60-80%.

[0037] (9) High-temperature and high-pressure composite curing: The pre-pressed qualified glass plate is placed vertically on the operating rack of the autoclave. In order to eliminate the air bubbles generated in the interlayer during the composite curing process and reduce the internal stress of the interlayer glass, the process parameters of the autoclave are controlled in 6 stages; at the same time, in order to ensure heating uniformity and reduce internal stress, the traditional infrared heating method is changed to microwave heating method. The first stage is heating and pressurizing, with the temperature rising from room temperature to 60-80℃ and the pressure rising from atmospheric pressure to 0.6-0.8 MPa, then held for 60-90 minutes. The second stage is holding the pressure while heating, maintaining the pressure and raising the temperature from 80℃ to 300-360℃, then held for 180-240 minutes. The third stage is isothermal heating and pressurizing, maintaining the temperature and raising the pressure to 1.2-2.0 MPa, then held for 30-60 minutes. The fourth stage is isothermal and isobaric, maintaining both temperature and pressure for 60-90 minutes. The fifth stage is isothermal cooling, maintaining the pressure and slowly lowering the temperature to 40℃, a process that takes 360-480 minutes. The sixth stage is venting; when the temperature is below 40℃, venting can be slowed until the pressure reaches 0.03-0.05 MPa, the temperature drops to room temperature, and then held for 60-90 minutes. Finally, venting can be reduced to atmospheric pressure, and the autoclave can be opened to remove the laminated glass for quality inspection.

[0038] (10) Post-processing of laminated glass: The laminated glass that has passed inspection is mechanically cut to meet the tolerance requirements, and then subjected to post-processing operations such as optical surface polishing, coating, protection, and packaging.

[0039] Example

[0040] In this embodiment, the radiation-proof glass model is ZF501; the glass size is 1100 mm × 600 mm × 120 mm; the number of glass pieces is 2; the special polymer resin is polyaryletherketone (PAEK) optical film; the film thickness is 0.192 mm; the number of films is 1.

[0041] Molding process flow as follows Figure 1 As shown, the process parameters for the key processes are as follows:

[0042] Vacuum degassing and pre-compression process parameters: A two-stage preheating, vacuuming, and degassing process is adopted. The first stage has a furnace temperature of 120±5℃, a vacuum degree of 0.03±0.005 MPa, and a holding time of 70±3 min. The second stage has a furnace temperature of 220±5℃, a vacuum degree of 0.01±0.005 MPa, and a holding time of 120±3 min. After completion, the vacuum is unloaded after natural cooling to room temperature within the laminating furnace.

[0043] High-temperature and high-pressure composite curing process parameters: The process parameters of the autoclave are controlled in six stages. The first stage is heating and pressurizing, with the temperature rising from room temperature to 75±5℃ and the pressure rising from atmospheric pressure to 0.6 MPa, then held for 75±3 min. The second stage is holding and heating, maintaining the pressure while raising the temperature from 80℃ to 340±5℃, then held for 200±3 min. The third stage is isothermal and pressurizing, maintaining the temperature while raising the pressure to 1.5±0.1 MPa, then held for 45±3 min. The fourth stage is isothermal and isobaric, maintaining the temperature and pressure for 75±3 min. The fifth stage is isothermal and cooling, maintaining the pressure while slowly lowering the temperature to 40℃, this process takes 400±5 min. The sixth stage is venting, where venting is only allowed when the temperature is below 40℃, slowly venting to a pressure of 0.04±0.005 MPa, lowering the temperature to room temperature, and then holding for 75±3 min. Finally, venting to atmospheric pressure is allowed, the autoclave is opened, and the laminated glass is removed for quality inspection.

[0044] The products manufactured according to the above embodiments were cut and sampled, and their irradiation stability was tested according to Q / CNPE J104.65-2011 "Technical Conditions for Radiation-Proof and Radiation-Resistant Glass for Peeping Windows". The radiation source was a Co-60 gamma-ray source. The irradiation conditions and the white light transmittance before and after irradiation are as follows: Figure 2 As shown. Figure 2 The horizontal axis represents the wavelength of light, and the vertical axis represents the transmittance of light. Figure 2 It can be seen that the light transmittance of the laminated glass before and after irradiation remains basically unchanged, which meets the requirements of Q / CNPE J104.65-2011 "Technical Conditions for Radiation-resistant Glass for Peeping Windows".

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A dry forming method for ultra-thick, radiation-resistant, and nuclear-proof laminated glass for viewing windows, characterized in that... The method includes the following steps: Glass plate pretreatment: After cleaning and air drying the glass plate, an electrostatic film for protection is attached to the non-adhesive surface; The specific steps for cleaning glass plates are as follows: the glass plates are cleaned in three stages. The first and second stages use tap water heated to 40-60℃, and the third stage uses deionized water or reverse osmosis water to remove salt from the tap water. The resistivity of the deionized water or reverse osmosis water is >10 MΩ or the conductivity is <10 μs. Polymer resin film cutting and conditioning: Cut the polymer resin film to the size that matches the glass plate and condition it in a clean space; The polymer resin film is a polyaryletherketone optical film or a thermoplastic polyimide resin transparent optical film. Adhesive film laying, trimming and lamination: The polymer resin adhesive film is laid on the surface of the glass plate to be bonded, and then the glass plate to be bonded is stacked on top of the glass plate with adhesive film laid. Vacuum degassing and pre-compression: The assembled glass plate is subjected to vacuum degassing until there are no bubbles or impurities and the transparency is 60-80%; The vacuum degassing and pre-pressurization process employs a two-stage preheating vacuum degassing method. In the first stage, the furnace temperature is 90-140℃, the vacuum degree is ≤0.08 MPa, and the holding time is 60-90 min. In the second stage, the furnace temperature is 180-240℃, the vacuum degree is ≤0.08 MPa, and the holding time is 90-140 min. High-temperature and high-pressure composite curing and post-treatment: The glass plate is subjected to high-temperature and high-pressure composite curing and post-treatment to complete the dry forming of ultra-thick viewing window anti-nuclear radiation resistant laminated glass; The high-temperature and high-pressure composite curing process consists of six stages, with the specific process parameters as follows: The first stage is heating and pressurizing, where the temperature rises from room temperature to 60-80℃ and the pressure rises from atmospheric pressure to 0.6-0.8 MPa, then held for 60-90 minutes. The second stage is holding and heating, where the pressure remains constant and the temperature rises from 80℃ to 300-360℃, then held for 180-240 minutes. The third stage is isothermal and pressurizing, where the temperature remains constant and the pressure rises to 1.2-2.0 MPa, then held for 30-60 minutes. The fourth stage is isothermal and isothermal, where the temperature and pressure remain constant for 60-90 minutes. The fifth stage is isothermal and cooling, where the pressure remains constant and the temperature slowly decreases to 40℃, a process that takes 360-480 minutes. The sixth stage is venting, where when the temperature is below 40℃, venting is performed until the pressure reaches 0.03-0.05 MPa, the temperature drops to room temperature, then held for 60-90 minutes. Finally, venting is performed back to atmospheric pressure. The heating method for vacuum degassing pre-compression and high-temperature high-pressure composite curing is microwave heating.

2. The dry forming method for ultra-thick peephole window anti-nuclear radiation resistant laminated glass according to claim 1, characterized in that, The air-drying temperature is 120-150℃.

3. The dry forming method for ultra-thick peep window anti-nuclear radiation resistant laminated glass according to claim 1, characterized in that, The length and width dimensions of the polymer resin film are 5-6 mm larger than the length and width dimensions of the glass plate bonding surface.

4. The dry forming method for ultra-thick peep window anti-nuclear radiation resistant laminated glass according to claim 1, characterized in that, The environmental parameters for conditioning are: moisture content ≤0.2%, ambient temperature 23-25℃, humidity 25-30%, and conditioning time not less than 24 hours.

5. The dry forming method for ultra-thick peep window anti-nuclear radiation resistant laminated glass according to claim 1, characterized in that, When laying, use low-tack tape to adhere along the excess parts of the edge, and remove the low-tack tape after the pieces are assembled.

6. The dry forming method for ultra-thick peep window anti-nuclear radiation resistant laminated glass according to claim 1, characterized in that, The post-processing includes cutting, polishing, coating, protection, or packaging.

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