Blog Details
- Home
- Blog Details
Bonding and edge treatment of tempered laminated glass products
Laminated glass products are popular in the market because of their excellent properties. As an indispensable material for laminated glass, interlayer film affects the performance and quality of the entire glass product to a large extent. Currently, the more commonly used interlayer film materials for laminated glass on the market include polyvinyl butyral (Poly Vinyl Butyral, PVB) and the high hardness interlayer film Sentry Glass Plus (SGP) introduced by DuPont. The tear strength of SGP is 5 times that of ordinary PVB, and the hardness is nearly 100 times higher, which can greatly improve the impact resistance of laminated glass; it has the same breaking safety and fragment retention ability, stability and high temperature resistance. better. Table 1 shows the performance comparison of these two types of interlayer films, Glass product .
Performance comparison of SGP and PVB interlayers
Comparison of SGP/PVB performance and bonding mechanism. The adhesion of PVB interlayer to glass originates from the hydrogen bond formed between the C-OH groups in the polyvinyl butyral film and the abundant Si-OH on the glass surface. Since SGP is still a technical secret, according to its product introduction, its components are ethylene and methacrylate copolymers containing 1% sodium ions. , may also be mainly from the ionic bond of the Na+ component contained in it, and its bonding mechanism is speculated.
Schematic diagram of bonding mechanism between PVB and SGP and glass non-tin surface
For multi-layer sandwich products, it is necessary to control the pressure in the autoclave in different ranges at multiple temperature values, and reduce the air residue in the vacuum bag as much as possible to obtain excellent appearance quality, common temperature/pressure-time set up.
Temperature/pressure-time curve in the autoclave
Common process defects and control points of sandwich products. Bubble is the most common process defect in sandwich products (Figure 3a). The direct reason is that the small bubbles remaining in the pre-pressed product under high temperature and high pressure are not completely dissolved into the film. When the intermediate film is in a fluid state, the residual bubbles converge. made later. When the flatness of the tempering exceeds the limit or there is a process error in the pre-rolling, the edge of the pre-press is not closed well, and it will cause "air blowing" when it is pressurized in the autoclave. Bubble defect.
Defective bubbles in laminated products
At present, the common quality defects on the edge of multi-layer laminated products mainly include poor stacking, white lines and rough edges, as shown in Figure 4. For the edges of sandwich products, common poor quality mainly includes poor stacking, white lines and rough edges
Poor appearance of multi-layer laminated products after trimming
Trim-free lamination process sandwich product case. For SGP, due to its low viscosity and good flow and filling effect at the lamination temperature, based on this characteristic, other auxiliary materials that are not bonded to SGP are used to make the liner shaping mold, and the SGP is saturated and filled under vacuum process conditions. The gap between the glass and the mold forms a set of trim-free process to avoid external force damage to the film in the later stage, which can greatly improve the quality of the edge. Figure 5 shows the effect of anomalous edge of a mass-supplied product of SGP ultra-thick triple-laminated glass rib with anomalous edge provided by a trim-free process for a complex.
Special-shaped surface of ultra-thick triple-laminated glass rib with special-shaped cutting surface
The development trend of laminated glass products: (1) Curtain walls and some indoor laminated products are not only large in size, but also composite products of various glass processes, including Low-E glass, special-shaped cutting and grinding, drilling , Slotting, color glaze, flat tempering, bending tempering, hot bending and hot dipping, etc. (2) The complexity of the process of sandwich products further leads to higher quality loss of the products, and the requirements for each pre-process, such as cutting and tempering, are greatly improved. (3) The price of glass substrates in Mainland China has risen rapidly in recent years, and at the same time, the price of plastic films, which are by-products of petrochemicals, has also been rising, and the overall cost of raw materials is under great pressure.
Performance comparison of SGP and PVB interlayers
Comparison of SGP/PVB performance and bonding mechanism. The adhesion of PVB interlayer to glass originates from the hydrogen bond formed between the C-OH groups in the polyvinyl butyral film and the abundant Si-OH on the glass surface. Since SGP is still a technical secret, according to its product introduction, its components are ethylene and methacrylate copolymers containing 1% sodium ions. , may also be mainly from the ionic bond of the Na+ component contained in it, and its bonding mechanism is speculated.
Schematic diagram of bonding mechanism between PVB and SGP and glass non-tin surface
For multi-layer sandwich products, it is necessary to control the pressure in the autoclave in different ranges at multiple temperature values, and reduce the air residue in the vacuum bag as much as possible to obtain excellent appearance quality, common temperature/pressure-time set up.
Temperature/pressure-time curve in the autoclave
Common process defects and control points of sandwich products. Bubble is the most common process defect in sandwich products (Figure 3a). The direct reason is that the small bubbles remaining in the pre-pressed product under high temperature and high pressure are not completely dissolved into the film. When the intermediate film is in a fluid state, the residual bubbles converge. made later. When the flatness of the tempering exceeds the limit or there is a process error in the pre-rolling, the edge of the pre-press is not closed well, and it will cause "air blowing" when it is pressurized in the autoclave. Bubble defect.
Defective bubbles in laminated products
At present, the common quality defects on the edge of multi-layer laminated products mainly include poor stacking, white lines and rough edges, as shown in Figure 4. For the edges of sandwich products, common poor quality mainly includes poor stacking, white lines and rough edges
Poor appearance of multi-layer laminated products after trimming
Trim-free lamination process sandwich product case. For SGP, due to its low viscosity and good flow and filling effect at the lamination temperature, based on this characteristic, other auxiliary materials that are not bonded to SGP are used to make the liner shaping mold, and the SGP is saturated and filled under vacuum process conditions. The gap between the glass and the mold forms a set of trim-free process to avoid external force damage to the film in the later stage, which can greatly improve the quality of the edge. Figure 5 shows the effect of anomalous edge of a mass-supplied product of SGP ultra-thick triple-laminated glass rib with anomalous edge provided by a trim-free process for a complex.
Special-shaped surface of ultra-thick triple-laminated glass rib with special-shaped cutting surface
The development trend of laminated glass products: (1) Curtain walls and some indoor laminated products are not only large in size, but also composite products of various glass processes, including Low-E glass, special-shaped cutting and grinding, drilling , Slotting, color glaze, flat tempering, bending tempering, hot bending and hot dipping, etc. (2) The complexity of the process of sandwich products further leads to higher quality loss of the products, and the requirements for each pre-process, such as cutting and tempering, are greatly improved. (3) The price of glass substrates in Mainland China has risen rapidly in recent years, and at the same time, the price of plastic films, which are by-products of petrochemicals, has also been rising, and the overall cost of raw materials is under great pressure.
Leave a comment