Nano Calcium Carbonate Boosts Sealant Performance but Shows Heat Sensitivity

Nano calcium carbonate is one of the most widely used functional fillers in the sealant industry, capable of increasing the volume of sealants and enhancing their tensile strength, wear resistance, tear resistance, hardness, and other properties.

Appearance

The appearance of sealant primarily depends on the dispersion of fillers in the base adhesive. Fillers are solid powders that, after being dispersed by kneading machines, grinding machines, and planetary mixers, can be evenly distributed in the base adhesive to form a fine paste. Depending on the inherent properties of the fillers, there may occasionally be a small amount of fine particles or sand, which is considered an acceptable normal phenomenon.

Hardness

Hardness refers to the hardness of the sealant after it has completely cured into a rubber body, and is one of the physical and mechanical properties of the product. Hardness refers to the ability of a material to resist the attempt of substances to scratch or press into its surface. The hardness of the sealant is high, but the surface sealant has strong rigidity and insufficient elasticity and flexibility; The opposite is true for low hardness, good elasticity and flexibility, but insufficient rigidity. Therefore, sealant is neither harder nor softer, but has certain range requirements according to actual needs.

Tensile Strength

Tensile strength is also one of the mechanical properties of sealant after complete curing. Tensile strength, also known as tensile strength or tensile strength, is commonly referred to as tensile strength. It refers to the ability of a material to resist damage when subjected to tension.

According to its usage needs, sealant needs to have certain strength requirements, especially for structural adhesives. The minimum strength value is clearly specified in the national standard, and sealant with poor strength cannot meet the usage needs. However, it is not advisable to overly emphasize the strength of the sealant while neglecting its elasticity.

Mechanical Properties of Sealant under Standard Conditions

The tensile strength and elongation at break of the sealant made of nano calcium carbonate are close. Nano calcium carbonate, with a particle size of around 50nm and a large specific surface area, has multiple contact points (reinforcement points) with the sealant polymer in the system. It can form strong interactions with the sealant molecular interface, preventing crack propagation, generating shear bands, absorbing energy, and increasing the tensile strength and elongation of the sealant, thereby possessing better toughness and impact tear resistance.

Mechanical Properties of Sealant at High Temperature of 90 ℃

After high-temperature treatment at 90 ℃, the tensile strength and elongation at break of the sealant significantly decreased. Among them, the sealant products made of nano calcium carbonate showed the most significant decrease in strength and elongation. This is because the specific surface area and heating area of nano calcium carbonate are large, and its reinforcement effect is more easily affected by high-temperature treatment.

Summary

While nano calcium carbonate significantly enhances sealant strength, elasticity, and durability at standard conditions, its performance drops notably under high-temperature exposure—highlighting the need for balanced formulation design to meet diverse application demands.