Release agents perform the key task of preventing bonding of material to mold. They also perform additional functions during the molding process such as reducing production time, facilitating cleanup and extending the life of the mold.
Concrete Release Agents
Release agents are needed during concrete production to prevent concrete from sticking to the formwork and to ensure easy removal of formwork without surface damage. It also enhances the appearance of precast by minimizing the inconsistencies, such as blow/bug holes on the surface.
Concrete release agents consist of a base fluid in which the required additives are dissolved. The base fluid can be mineral oil or water. Petroleum oil has traditionally served as a base fluid for the active ingredients in solvent-based release agents. However, uncertain oil prices and increasing environmental concerns are the reasons why manufacturers are transitioning towards water based release agents.
Below are some of the advantages and disadvantages of Solvent-based & Water-based release agents.
Water Based Release Agent
- Contains very low VOC and is therefore considered environment friendly.
- Doesn’t contain harmful solvents and therefore doesn’t pose health risk to workers.
- Water based release agent is generally non-flammable.
- Cheaper & stable price due to free availability of water.
- Water based release agent is odorless during spraying.
- Freezes when temperature drops and is only usable after thawing.
- Has to be shaken before use, as the active ingredients are dissolved via an emulsifying agent.
- Shorter application temperature range compared to Solvent-based release agent.
- Can contribute to rust formation when used on mild steel forms.
Solvent-based Release agent
- Solvent-based concrete release agents are highly effective at keeping concrete from sticking to formwork.
- No need for vigorous shaking before use as the component are readily dissolved in solvent.
- Petroleum base permits usage in cold conditions due to low melting point.
- Wider application temperature range compared to water-based release agent.
- Doesn’t cause rust formation & is not susceptible to bacterial/fungal attack.
- Solvent-based release agent has higher VOC (volatile organic content) and hence pose a health risk to workers.
- Price of Solvent-based release agent is subject to the price of crude oil and is therefore high & fluctuating.
- Tougher VOC standards regulate the usage.
- Solvent-based release agent has lower flash point and requires careful storage & handling.