Development of Glass with Controlled Chemical Durability
Traditionally, glass has been required to offer properties such as water resistance, weather resistance, and durability against alkalis and acids, depending on its intended use. However, in the field of electronic components, glass is now expected to withstand exposure to special chemicals or gases that are rarely encountered in other applications.
For glass substrates, durability requirements have shifted. Instead of merely providing resistance to chemical solutions, there is now an increasing demand for glass that can withstand specific chemicals while enabling efficient surface treatments, like etching, within a short timeframe.
The chemical durability of glass is largely determined by its composition. We develop and offer a wide range of glass materials with customized durability to meet the unique demands of various chemicals and applications.
| Glass with enhanced chemical durability (minimized property degradation and glass component leaching) |
Building glass with enhanced chemical durability | Glass with controlled chemical durability for specific chemical etching processes |
|
|
|
Contents
Sidebar: Chemical Durability of Glass
Chemical durability refers to a material's resistance to chemical corrosion, and glass is generally considered to have high chemical durability. It is particularly resistant to water and acids, due to its composition of covalently bonded oxides, primarily SiO2. The SiO2 network structure—the core framework of glass—is highly resistant to water and most acids.
However, glass is not resistant to hydrofluoric acid, which is commonly used for glass processing and cleaning platinum fixtures. Hydrofluoric acid reacts with the SiO2 network structure, breaking it down and dissolving the material. Similarly, common glass is vulnerable to alkaline aqueous solutions. At pH levels of 11 or higher, the OH groups in the alkaline solution disrupt the SiO2 network structure, causing the glass components to dissolve.
In addition to acid and alkali resistance, moisture can also cause minor chemical corrosion. Glass with low water resistance can react with moisture from the atmosphere or solution, triggering processes like the elution of metal ions from the surface or the gelling of the surface layer. If the resulting SiO2 gel dissolves into water, significant corrosion can occur. Furthermore, acidic gases like CO2 and SO2 in the air can react with ions such as Na⁺ and Ba²⁺ that elute from the glass due to surface moisture. These reactions form compounds (e.g., Na2CO3, BaSO4) on the glass surface, leading to cloudiness and surface weathering.
Glass with Enhanced Chemical Durability
Traditionally, glass has been valued for its water resistance, weather resistance, and durability against alkalis and acids, depending on its application. In pharmaceutical containers, glass must remain inert and not interact with the substances it holds. This is why borosilicate glass, known for its excellent resistance to hydrolysis (water resistance and alkali leaching), as well as superior acid and alkali resistance, is widely used. Among these properties, preventing the leaching of alkali components is one of the most critical requirements for pharmaceutical containers. Our glass tubing for pharmaceutical containers, BS and BS-A, delivers exceptional chemical durability through precise control of its composition. These products are used in pharmaceutical applications such as ampoules and vials, as well as in physicochemical containers like test tubes. As medical technology advances, we are actively developing glass materials to meet a wide range of evolving needs.
In the field of electronic components, special chemicals or gases—rarely encountered in other applications—are sometimes used, requiring glass to be durable against these unique substances.
For example, one of the key properties required for glass substrates of liquid crystal display is their resistance to the chemicals used in wet etching and cleaning processes during the display manufacturing process. There is also an increasing demand for glass that can withstand dry etching processes, where gases replace chemical solutions. This requires specialized chemical durability designed for gaseous environments.
Our glass substrates, including OA-11, OA-20, OA-31, and the chemically strengthened Dinorex™, offer outstanding chemical durability through precise composition control, making them ideal for these advanced applications.
Building Glass with Enhanced Chemical Durability
Glass fiber is commonly used as reinforcement in concrete, improving its tensile strength and toughness, and is widely employed in construction and civil engineering materials. However, since concrete has strong alkalinity, the glass fibers used as reinforcement must also be resistant to alkalis. Our ARG Fiber: WizARG™ developed specifically for these composite materials, contains a high concentration of zirconia, providing excellent alkali and acid resistance. It has been used for over 40 years in the construction and civil engineering industries as a reinforcing material for glass fiber reinforced concrete (GRC), calcium silicate products, and as a crack suppression agent in mortars and concrete.
Additionally, our glass-ceramic building material: Neopariés, is six times more alkali-resistant than marble and twice as resistant as granite, offering exceptional chemical durability. In terms of water absorption, marble has a rate of 0.30%, granite 0.35%, while Neopariés has 0% water absorption. This means that no water can seep inside, completely eliminating the risk of frost damage. As a result, Neopariés exhibits superior chemical durability as an exterior building material.
Glass with Controlled Chemical Durability
Chemical etching is a critical factor in the chemical durability of liquid crystal glass substrates.
During the manufacturing process of liquid crystal display (LCD) panels, glass substrates are chemically etched to reduce their thickness. Traditionally, the focus has been on ensuring that glass resists chemical solutions, but there is now a growing demand for glass that offers a high etch rate to boost productivity.
By adjusting the composition of the glass, we have developed materials that provide precise control over the etching rate. This includes making the glass easier to dissolve or, in some cases, more resistant to dissolution, depending on the specific chemical solutions used in the customer's manufacturing process.