Frequently asked questions about sealants and adhesives
There are many differences between acrylic and silicone. We have listed the main differences below:
- Elasticity: Silicone is elastic, i.e. flexible. Acrylates, on the other hand, are plastoelastic – they are moderately flexible and are more prone to cracks.
- Suitability for painting: Unlike acrylates, silicones cannot be painted. Silicone is available in individual colors, acrylate is not.
- Water permeability: Silicone is waterproof – acrylic, on the other hand, should only be used with a moderate moisture load.
- Odour: Depending on the crosslinking reaction, silicone either has a specific odor or is odorless.
- Loss of volume/shrinkage: Since water evaporates while acrylic is curing, acrylates generally have significantly higher shrinkage than silicones.
Since silicones are waterproof, they are often used in sanitary facilities (with fungicidal option). Furthermore, thanks to their elastic properties, they are used in expansion joints. Acrylates are recommended for areas with moderate moisture and tensile load, and are therefore often used indoors. Note: We offer special acrylic and/or silicone sealants according to the area of application. You can find the perfect product for your project in our application assistants.
How quickly silicone-based sealants cure depends on several factors. A high temperature and humidity speed up curing. Normally, silicone cures from the outside in, and 2-3 millimeters will have cured within the first 24 hours. Over the following days, curing slows down because water from the surroundings, which is required for the reaction, must first penetrate through the cured silicone layer. Which means: The thinner the joint, the quicker it cures. Note: Fission products are released during curing and the silicone may smell.
Acrylic dries when the water evaporates from the joint. How fast it dries depends, among other things, on the humidity and temperature in the respective room, the layer thickness, and the substrate on which the acryl was applied. The drying process takes longer with high humidity and/or low temperatures.
The following applies for both silicone sealants and acrylic sealants: Store the cartridges as cool (max. +20 °C) and dry as possible and avoid extreme temperature changes. Note: Since acrylate sealants contain water, they should never be exposed to frost.
The amount of silicone or acrylic you need depends on the diameter of respective joint. In principle, the following applies for both silicone and acrylic-based sealants: Joint witdh (mm) x joint depth (mm) = amount of sealant (ml) needed per running meter of joint (rm). Or calculated the other way round: Cartridge content (ml) / consumption (ml) per rm = possible joint length (rm).
Silicone is waterproof or water-repellent. That’s why a silicone-based sealant is the right choice in sanitary facilities and generally in areas in which there is a certain degree of moisture. Furthermore, our silicone sealants for sanitary facilities contain a suitable fungicide which prevents mold growth.