Processing method of LOW-E interlayer hollow glass containing protective layer

Abstract

The invention provides a processing method of LOW-E laminated hollow glass containing a protective layer, and relates to the technical field of glass process.The two faces of a substrate and an original sheet are respectively coated with a protective film in a roller coating mode, the processing performance of the glass can be improved, the glass can have a similar heating environment in the tempering process, and then edge warping is prevented.

Description

Technical Field

[0001] This invention relates to the field of glass processing technology, and in particular to a method for processing LOW-E laminated insulating glass with a protective layer. Background Technology

[0002] Coated glass, also known as reflective glass, is made by coating one or more layers of metal, alloy, or metal compound film onto the glass surface to alter its optical properties and meet specific requirements. Coated glass utilizes magnetron sputtering to physically coat the glass interface, reducing heat loss due to radiation, effectively suppressing infrared light transmission, and minimizing heat exchange between the glass sides, thus achieving excellent energy-saving, optical, and environmental performance. This makes it highly favored by architects and widely used in buildings worldwide. However, due to the multiple layers of metal coating, various quality defects such as scratches, suction cup marks, and oxidation can occur during the steel cutting and grinding process. To avoid these quality issues, a protective film is rolled onto the coating surface. However, this method fails to meet the processing requirements for laminated products after tempering, resulting in quality problems such as bubbles and delamination. It also fails to meet the quality requirements for insulated laminated products. This paper designs and invents a method for processing LOW-E large-format sheets with a protective film rolled onto the coating surface, enabling steel cutting, grinding, and then insulating the laminated glass. This method satisfies the processing requirements for LOW-E large-format tempered laminated insulated products.

[0003] Existing technologies for manufacturing coated laminated insulating glass typically include the following three types:

[0004] 1) The surface of the LOW-E large plate has no roller coating protective film. During the steel cutting and grinding process, the film surface is not protected by any measures, which leads to quality defects such as scratches, oxidation, and suction cup marks on the film surface during processing, resulting in low yield and increased cost.

[0005] 2) Without a solution for protecting the film surface, the steel sandwich coating process is the most common sandwich coating process currently on the market. However, this process suffers from low yield, difficulty in adjusting the coating color, and wasted efficiency. Ultimately, this method results in high costs and cannot fully utilize coating capacity. For factories without a coating production line, it is impossible to process LOE-E sandwich hollow products.

[0006] 3) Cutting and grinding tempered coating and then sandwiching process: This process reduces waste and increases the overall yield, but the small pieces processed by the coating line cannot be fully utilized, resulting in wasted capacity of heavy-asset coating equipment and relatively high costs.

[0007] 4) A protective coating is rolled onto the LOW-E surface to protect the film quality and ensure normal processing while maintaining the yield rate of steel cutting and grinding.

[0008] 5) Low-E glass with a protective film layer has the following problems during the tempering and lamination process:

[0009] The protective film roller-coated on the coated surface has a certain degree of hardness, which can effectively protect the film surface from damage caused by contact between the slicing, edge grinding and the film surface. During the tempering process, the roller-coated protective layer first absorbs heat. As the temperature rises, the roller-coated protective layer burns and releases heat. At this time, the heat release will disrupt the temperature uniformity of the upper and lower surfaces, causing the tempered glass to fail to meet the requirements of the lamination process.

[0010] Due to the uneven temperature distribution on the upper and lower surfaces caused by the burning of the protective layer, the edge of the tempered glass warps upwards after tempering, while clear glass does not exhibit this warping. When the two pieces of glass are overlapped, a gap exists within 10 mm at the edge. The lamination rolling process primarily involves heating the glass and film, then using rolling to expel air from the film, requiring edge sealing. The remaining gas is then absorbed under high pressure. Under a specific temperature and pressure in an autoclave, the film thoroughly absorbs any residual air, forming a qualified transparent laminated product. Warping within 20 mm at the edge of the laminated glass (e.g.) Figure 1 As shown in the image, when the laminated glass is passed through the roller press furnace, the edges are not sealed, resulting in air bubbles at the edges of the laminated glass. The presence of air bubbles in the laminate makes it impossible to meet national requirements and thus prevents the lamination of hollow sections. Summary of the Invention

[0011] To address the shortcomings of existing technologies, this invention proposes a processing method for preventing edge warping in LOW-E laminated insulating glass with a protective layer.

[0012] To achieve the above objectives, the present invention adopts the following technical solution: a method for processing LOW-E laminated insulating glass with a protective layer, characterized by comprising the following steps:

[0013] Raw materials: Low-e glass sheets are selected as substrates. The substrate types include heat-reflective, single-silver, double-silver, and triple-silver coating types. After coating the sheet, a protective film is rolled onto each of the two surfaces and cured by infrared. The cured roll-coated protective layer has a certain hardness, which can protect the film layer in subsequent processing.

[0014] Slicing: Select raw glass sheets and cut them according to production requirements; during the cutting process, the work surface needs to be cleaned after each batch of raw sheets is cut, and a vacuum cleaner is used to remove broken glass shards to prevent scratches on the glass surface; the cutting head is selected with an angle 10° smaller than normal and the pressure is increased by 20% to cut the LOW-E large sheet with a protective film. After cutting, a protective film consistent with the substrate is also rolled onto both sides of the raw sheet and cured with infrared light;

[0015] Grinding and cleaning: The glass substrate is ground and cleaned. For ordinary Low-E substrates, the brush height of the cleaning machine needs to be adjusted, increasing it by 3 mm above the actual height. For large Low-E boards with a protective layer, the edge grinding and cleaning machine can be used normally without changing any process parameters. Any edge grinding equipment can be selected for processing, including manual operation, without damaging the film surface.

[0016] Tempering: Traditional LOW-E large-format glass processing uses an upper-mounted internal circulation forced convection tempering furnace. Special adjustments to process parameters are made to meet both tempering performance and quality requirements, as well as the requirements for laminated production. However, for LOW-E film glass with a protective layer, the upper surface of the protective layer has an exothermic effect, disrupting the uniformity of temperature between the upper and lower surfaces during normal processing and causing edge warping. Therefore, it is necessary to install compressed air convection below the tempering heating element, and a flow meter with readable pressure readings is required. This lower compressed air convection counteracts the heat released by the combustion of the protective layer, ensuring the glass remains flat within the furnace and meets the quality requirements for laminated glass after completion.

[0017] Lamination: The lamination is produced using forced convection equipment. Tempered Low-e glass is laminated with tempered glass in the lamination lamination room. PVB film or SGP ion exchange membrane is used as the intermediate medium between the glass layers. After lamination, an electrostatic film is laid on the film surface to protect it from damage.

[0018] Firing kettle: Production is carried out according to standard firing kettle parameters, and the membrane is protected before entering the kettle.

[0019] Insulating glass: Based on the glass size, use an automatic frame bending machine to bend the aluminum strip and fill it with desiccant. Then, use a butyl glue machine to evenly apply butyl glue to both sides of the aluminum strip. Place the laminated glass on one side of the aluminum frame strip coated with butyl glue, and put the dried tempered glass (or heat-strengthened glass) on the other side of the aluminum frame strip. Then, use structural adhesive for a second seal, and finally, the laminated insulated glass product is formed. This is how offline Low-e laminated insulated glass can be produced.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. Due to the increased convection of compressed air, the temperature difference between the upper and lower sides of the glass surface is weakened, reducing the probability and extent of edge warping;

[0022] 2. By rolling a protective film onto both sides of the substrate and the original sheet, the two sides of the glass have similar protective film combustion environments during the tempering process when the protective film burns off, thus weakening the temperature difference.

[0023] 3. The protective film not only reduces the temperature difference during tempering, but also protects the glass during processing, improves glass processing performance, and reduces the defect rate. Attached Figure Description

[0024] Figure 1 This is a schematic diagram illustrating edge warping that occurs in existing processes. Detailed Implementation

[0025] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0026] Raw materials: Low-e glass sheets are selected as substrates, including heat-reflective, single-silver, double-silver, and triple-silver coating types; after coating the sheets, a protective film is rolled onto both sides of the glass and cured by infrared. The cured roll-coated protective layer has a certain hardness, which can protect the film layer in subsequent processing.

[0027] Slicing: Select raw glass sheets and cut them according to production requirements; during the cutting process, the work surface needs to be cleaned after each batch of raw sheets is cut, and a vacuum cleaner is used to remove broken glass shards to prevent scratches on the glass surface; the cutting head is selected with an angle 10° smaller than normal and the pressure is increased by 20% to cut the LOW-E large sheet with a protective film; after processing, a protective film consistent with the protective film on the substrate is rolled onto both sides of the raw sheet.

[0028] Grinding and cleaning: The glass substrate is ground and cleaned. For ordinary Low-E substrates, the brush height of the cleaning machine needs to be adjusted, increasing it by 3 mm above the actual height. For large Low-E boards with a protective layer, the edge grinding and cleaning machine can be used normally without changing any process parameters. Any edge grinding equipment can be selected for processing, including manual operation, without damaging the film surface.

[0029] Tempering: Traditional LOW-E large-format glass processing uses an upper-mounted internal circulation forced convection tempering furnace. Special adjustments to process parameters are made to meet both tempering performance and quality requirements, as well as the requirements for laminated production. However, for LOW-E film glass with a protective layer, the upper surface of the protective layer has an exothermic effect, disrupting the uniformity of temperature between the upper and lower surfaces during normal processing and causing edge warping. Therefore, it is necessary to install compressed air convection below the tempering heating element, and a flow meter with readable pressure readings is required. This lower compressed air convection counteracts the heat released by the combustion of the protective layer, ensuring the glass remains flat within the furnace and meets the quality requirements for laminated glass after completion.

[0030] Lamination: The lamination is produced using forced convection equipment. Tempered Low-e glass is laminated with tempered glass in the lamination lamination room. PVB film or SGP ion exchange membrane is used as the intermediate medium between the glass layers. After lamination, an electrostatic film is laid on the film surface to protect it from damage.

[0031] Firing kettle: Production is carried out according to standard firing kettle parameters, and the membrane is protected before entering the kettle.

[0032] Insulating glass: Based on the glass size, use an automatic frame bending machine to bend the aluminum strip and fill it with desiccant. Then, use a butyl glue machine to evenly apply butyl glue to both sides of the aluminum strip. Place the laminated glass on one side of the aluminum frame strip coated with butyl glue, and put the dried tempered glass (or heat-strengthened glass) on the other side of the aluminum frame strip. Then, use structural adhesive for a second seal, and finally, the laminated insulated glass product is formed. This is how offline Low-e laminated insulated glass can be produced.

[0033] The tempered glass compressed air is turned on, as shown below:

[0034]

[0035] The tempering process temperature control differs from previous processes. Currently, a low-temperature tempering process is used, with an upper heating temperature of 640-655 degrees Celsius and a lower temperature of 620-640 degrees Celsius, and a glass heating time of 320-360 seconds. The upper power is set to 75 kW, and the lower power to 50 kW. Previously, the upper tempering temperature was 690 degrees Celsius and the lower temperature was 680 degrees Celsius. In this scheme, as the heating time progresses, the upper heating convection power is gradually increased while the lower heating convection power is decreased. Simultaneously, when the lower heating power is high, compressed air at approximately 4 atmospheres is used to increase convection efficiency and reduce the temperature difference between the upper and lower glass surfaces, preventing edge warping. Apart from providing compressed air, other process parameters are similar to traditional methods.

[0036] 4) The quality indicators of the tempered glass must meet the requirements of the direct roll forming process for laminated glass. Specific quality indicators after tempering are as follows:

[0037] E. Lamination: The lamination is produced using forced convection equipment. Tempered Low-e glass is laminated with tempered glass in the lamination lamination room. PVB film or SGP ion exchange membrane is used as the intermediate layer medium between the glass layers. After lamination, an electrostatic film is laid on the film surface to protect it from damage. The lamination process parameters are optimized as follows.

[0038] D. Adjust the lamination process parameters according to the processing characteristics of the glass film;

[0039]

[0040] E. Firing kettle: Production is carried out according to the conventional firing kettle parameters, and the membrane is protected before entering the kettle.

[0041] F. Insulating: According to the glass size, use an automatic frame bending machine to bend the aluminum strip and fill it with desiccant. Then, use a butyl glue machine to evenly apply butyl glue to both sides of the aluminum strip. Place the laminated glass on one side of the aluminum frame strip coated with butyl glue, and put the dried tempered glass (or heat-strengthened glass) on the other side of the aluminum frame strip. Then, use structural adhesive for a second seal, and finally, the laminated insulating glass product is formed. Offline Low-e laminated insulating glass can be produced.

[0042] This method uses a large LOW-E sheet with a roll-coated protective film on its surface, which is then cut, ground, and tempered before being laminated. After lamination, the sheet is then hollowed out. This modification to the process flow for laminated products improves product delivery and quality while reducing costs.

[0043] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A method for processing LOW-E laminated insulating glass with a protective layer, characterized in that, Includes the following steps: Raw materials: Low-e glass sheets are selected as substrates. After coating the sheets, a protective film is rolled onto both sides of the substrate and cured by infrared radiation. Slicing: Select a glass sheet and cut it according to production requirements. Roll a protective film onto both sides of the glass sheet and cure it using infrared technology. Grinding and cleaning: Grinding the edges of the glass sheet and cleaning the glass sheet; Tempering: By supplying compressed air to the space under the glass plate of the tempering furnace, the heat released by the combustion of the protective film by the convection of the compressed air is ensured to keep the glass flat in the furnace, reducing the probability and extent of edge warping that may be caused by the temperature difference between the upper and lower glass surfaces; Lamination: The lamination is produced using forced convection equipment. Tempered Low-e glass is laminated with tempered glass in the lamination lamination room. PVB film or SGP ion exchange membrane is used as the intermediate medium between the glass layers. After lamination, an electrostatic film is laid on the film surface to protect the film surface from damage. Firing kettle: Production is carried out according to standard firing kettle parameters, and the membrane is protected before entering the kettle; Insulating glass: Based on the glass size, use an automatic frame bending machine to bend aluminum strips and fill them with desiccant. Then, use a butyl glue machine to evenly apply butyl glue to both sides of the aluminum strips. Place the laminated glass on one side of the aluminum frame strip coated with butyl glue, and place the dried tempered glass on the other side of the aluminum frame strip. Then, use structural adhesive for a second seal, and finally, the laminated insulating glass product is formed. This process produces offline Low-e laminated insulating glass.

2. The method for processing LOW-E laminated insulating glass with a protective layer according to claim 1, characterized in that, The substrate types include heat-reflective, single-silver, double-silver, and triple-silver coating types.

3. The method for processing LOW-E laminated insulating glass with a protective layer according to claim 1, characterized in that, The protective films rolled onto the Low-e substrate and the glass substrate are of the same material and thickness.

Images