If you’ve worked with high-temperature silicone coatings, you’ve likely encountered low melting point glass powder in the formulation. But why is it such a critical ingredient? Let’s explore this question by analyzing a waterborne high-temperature silicone coating recipe, uncovering the pivotal role low melting point glass powder plays.

What Are High-Temperature Coatings?
High-temperature coatings are specialized functional coatings designed to withstand prolonged exposure to temperatures exceeding 380°C while maintaining physical and chemical integrity. These coatings are used on substrates like iron, steel, aluminum, ceramics, and glass, making them indispensable in industries such as metallurgy, petroleum, natural gas, and aerospace.
In addition to their heat resistance, these coatings offer durability against abrasion and impact. By modifying the surface of metals or refractory materials, they enhance the performance of base materials, save energy, and extend the lifespan of metal substrates by 1–2 times.

The Technology Behind High-Temperature Silicone Coatings
One standout material is the heat-resistant resin derived from functional silicone oligomers, such as SIOResin® SIO-715. Built around a polysiloxane backbone, this resin exhibits exceptional thermal stability due to the high bond energy of the silicon-oxygen (Si-O) bond.
Using this resin, a single-component, room-temperature-curable silicone coating can be formulated, capable of withstanding temperatures as high as 1200°C.

High-Temperature Silicone Coatings Starting Formulation
Here’s a starting formulation for a waterborne high-temperature silicone resin coating:
Black Pigment Slurry
Ingredient | Weight Parts | Function | Supplier |
Deionized water | 531.6 | Solvent | |
H-1772W Dispersant | 24 | Dispersant | SIOResin® |
BYK-420 (10%) Antisettling | 18 | Antisettling Agent | BYK |
Bentone LT (2%) | 24 | Antisettling Agent | BYK |
Foamex 810 Defoamer | 2.4 | Defoamer | BYK |
Low melting point glass powder (380°C) | 200 | Enhances high-temperature adhesion | |
Mica Powder | 100 | Improves low-temperature adhesion | |
Copper Chromite Black | 200 | Heat-resistant pigment | |
High-Purity Zinc Phosphate | 100 | Improves water and salt resistance |
Black High-Temperature Coating Formulation:
Ingredients | Weight Parts |
Silicone Resin Emulsion SIOResin® SIO-715 | 100 |
Black Pigment Paste | 20–67 |
Anti-Settling Agent (Bentone LT, 2%) | 4 |
Anti-Flash Rust Agent | 1 |
Epoxy Phosphate (Adhesion Promoter) | 1 |
Wetting Agent (TEGO 4100) | 0.3 |
Defoamer (TEGO Foamex 810) | 0.1 |
Thickener (SIOResin® H-1100D) | 1–2 |
The Role of Low Melting Point Glass Powder
In the black pigment formulation above, we can see the low melting point glass powder we are focusing on today. As we know, whether it is phenyl-based or methyl-based silicone resin, these resins undergo curing through either the baking of silanol groups or the hydrolytic condensation of alkoxysilane groups. At a certain temperature, the organic groups in the silicone resin, such as methyl and phenyl, begin to decompose gradually. When the temperature rises, the organic components of the silicone resin completely decompose, leaving voids that transform the resin into a loose, porous SiO₂ structure.
To address this, a certain amount of low melting point glass powder is incorporated during formulation design. When the temperature reaches the melting point of the glass powder, the powder begins to melt. This process not only fills the voids left by the decomposition of organic groups but also effectively replaces the silicone resin. It enhances adhesion to pigments and fillers, improving the coating’s performance. As a result, the high-temperature-resistant coating develops a “secondary film layer.” This additional layer provides crucial thermal insulation while also offering robust anti-corrosion protection for the substrate under high-temperature conditions.


Is Low Melting Point Glass Powder Environmentally Friendly?
Yes, all low melting point glass powder used in these formulations is lead-free. Since the formation of the Global Alliance to Eliminate Lead Paint in 2011, lead-containing products have been banned worldwide as of 2020.
Manufacturers must ensure compliance with safety and environmental standards, providing RoHS test reports to guarantee the absence of hazardous substances. Lead poisoning is entirely preventable, and responsible sourcing of raw materials is a key step.
Does SIOResin Produce Low Melting Point Glass Powder?
We do not manufacture low melting point glass powder. As a trusted supplier of eco-friendly resin materials, we often assist customers in sourcing high-quality, cost-effective, lead-free glass powder. If you need assistance, feel free to reach out to our sales team.
Let us help you achieve superior high-temperature coatings that combine safety, performance, and environmental responsibility.

Price: $5.9 /kg
About SIOResin (SIO New Material)
SIOResin is a leading company in China specializing in the development and production of new materials. We manufacture and supply high-quality water-based silicone resins, silicone-modified polyesters, water-based polyurethanes, water-based acrylics, UV resins, liquid silicone rubber, intumescent fireproof coatings, flame retardants, wetting agents, curing agents, associative thickeners, driers, soft-touch agents, and other additives. Our products have a wide range of applications and with competitive prices.
Free samples are available upon request. Please feel free to contact us at any time.
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