Achieving the required quality and durability for all types of glass demands more than just premium raw materials. Manufacturers and processors must meticulously manage the ambient climate, as uncontrolled variations in temperature and humidity can lead to significant product damage.
The glass industry, a rapidly evolving, high-technology sector, faces acute challenges related to temperature and moisture management. Inadequate relative humidity (RH) at various points in the production and storage cycle can result in substantial losses concerning product quality, efficiency, and financial outcomes. Thermomatic, specializing in HVAC-R engineering, positions itself as the essential strategic partner, delivering advanced moisture control systems to guarantee product excellence and long-term durability in glass manufacturing.
Despite its seemingly inert and impermeable nature, glass is not immune to atmospheric moisture. As an amorphous vitreous material, its surface continuously engages in a chemical reaction with airborne water and CO₂ molecules, resulting in the formation of a microscopic, hydrophilic silanol layer (Si–OH). This initial surface change is the catalyst for virtually all subsequent humidity-related defects in the glass industry.
In essence, the glass surface "exchanges" with its environment: it both adsorbs and desorbs water molecules, a process which fundamentally impairs adhesion, transparency, and optical stability, often initiating delamination.
This micro-hydrolysis process actively degrades chemical bonds and diminishes the surface energy—the exact conditions required for PVB, EVA, or TPU interlayers to achieve their maximum bonding strength.
Improper humidity levels can cause a range of harmful phenomena and consequences:
Every glass formulation possesses unique vulnerabilities and sensitivities to moisture, necessitating tailored environmental control strategies.
Float glass is particularly susceptible to both moisture and airborne contaminants. When stacked without adequate separation, condensation forming between the sheets can rapidly lead to irisation (rainbow-like staining) and alkaline corrosion. These defects result in permanent surface marks and a measurable reduction in optical transparency.
Ideal Conditions: Iridescence is triggered when the air's dew point surpasses the glass surface temperature. For instance, environments at 60% RH and 25°C can create the conditions for condensation during thermal shifts, initiating the corrosive process.
Composed of two or more glass layers bonded with an interlayer (PVB, EVA, or ionoplast), laminated glass is extremely sensitive to humidity. Polymers such as PVB and SentryGlas® are hygroscopic and absorb moisture from the air, interfering with adhesion and causing delamination, bubbles, cloudy stains, and loss of structural bonding.
Ideal Conditions:The lamination assembly room should maintain relative humidity between 20%–25% RH (±5%), not exceeding 30% RH. PVB rapidly absorbs moisture, reaching equilibrium with the environment in approximately two hours.
Produced through heating and rapid cooling, tempered glass requires strict temperature and humidity control during processing and cooling. Condensation on hot surfaces can cause post-tempering irisation, surface corrosion, and white stains, compromising both strength and aesthetics.
Contains an embedded metal mesh that creates zones of condensation and differential oxidation when exposed to humidity. This can lead to internal wire corrosion, surface irisation, and delamination between the wire and glass.
Composed of glass panes separated by a dehydrated or inert gas chamber, insulated glass is vulnerable to moisture infiltration. Humidity entering the chamber causes internal fogging, low-E coating corrosion, and spacer oxidation, compromising thermal and acoustic insulation.
Made from multiple glass and polymer layers, its ballistic integrity depends on interlayer adhesion, which is highly sensitive to humidity. Moisture absorption in polymers reduces cohesion, causing delamination, opacification, and decreased ballistic performance.
Consequences: Delamination in bulletproof glass can reduce ballistic resistance by 15–20%, leading to significant financial losses.
Flat glass with metallic and protective coatings on the back side, mirrors are highly susceptible to humidity-induced oxidation. This causes black spots (“black edge”), reflective film detachment, and loss of brightness.
Thermomatic offers high-accuracy HVAC-R systems for humidity control, redefining production standards in the glass and armor industries. The solutions are designed to meet the specific needs of each process stage, ensuring product quality and durability.
The glass industry primarily utilizes two distinct dehumidification technologies, each suited for different stages of the manufacturing process:
Ideal for environments where the temperature is not excessively low and humidity must be reduced to moderate levels (e.g., 40–60% RH). They work by thermal shock, condensing moisture to prevent reaching the dew point.
IThey are energy-efficient, providing lower operational costs (OPEX) and reduced capital expenditure (CAPEX).
These use a desiccant material (silica wheel) to adsorb moisture from the air. They are effective in achieving very low humidity levels (below 20–30% RH) and operate efficiently in cooler environments. They are essential for processes such as glass lamination with PVB/EVA. These more demanding conditions require higher CAPEX and OPEX investment, but payback is achieved through a significant reduction in lamination rejects.
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Implementing Thermomatic solutions results in tangible benefits and a fast return on investment:
Thermomatic is more than an equipment supplier; it is a strategic partner that understands the nuances of the glass industry and provides customized solutions to ensure maximum quality, safety and efficiency.
Invest in precise humidity and temperature control and elevate your production standards.
Contact our specialists to schedule a technical visit and discover how Thermomatic’s solutions can transform your glass production line.
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