What is release agent?
What is a release agent?
A release agent is a functional substance between the mold and the finished product. The release agent is chemically resistant and does not dissolve in contact with different resin chemistries (especially styrene and amines). The release agent also has heat and stress properties, and is not easy to decompose or wear; the release agent adheres to the mold without being transferred to the part being processed and does not interfere with painting or other secondary processing operations. Due to the rapid development of injection molding, extrusion, calendering, molding, lamination and other processes, the amount of mold release agent has also been greatly increased.
Characteristics of release agents
Theoretically, the release agent has a large tensile strength so it is not easy to polish when it is in constant contact with the molding resin. This is especially true when there are frosted mineral fillers or glass fiber reinforcements in the resin. The release agent is chemically resistant and does not dissolve in contact with different resin chemistries (especially styrene and amines). The release agent also has heat and stress properties, and is not easy to decompose or wear; the release agent adheres to the mold without being transferred to the part being processed and does not interfere with painting or other secondary processing operations.
The specific working principle of the release agent is as follows:
1. The polar chemical bond interacts with the mold surface to form an adsorption-type film with regenerative power;
2. The silicon-oxygen bond in the polysiloxane can be regarded as a weak dipole (Si+-O-). When the release agent spreads into a single orientation arrangement on the surface of the mold, the molecule adopts a unique extended chain configuration;
3. The free surface is covered by the alkyl group in a densely packed manner, and the demolding ability increases with the density of the alkyl group; but when the alkyl group occupies a large steric hindrance, the stretching configuration is limited, and the demolding ability will decrease;
4. The molecular weight and viscosity of the release agent are also related to the release ability. When the molecular weight is small, the spreadability is good, but the heat resistance is poor.
Functional applications of release agents
The reduction of volatile organic compounds (VOCs) and the elimination of health and safety concerns surrounding solvent-based release agents are the main drivers for the development of co-solvent release agents. Co-solvent-based release agents combine the benefits of solvent-based systems with the safety of water-based release agents.
One of the key attributes of a release agent is its durability: how long it will last before needing to be reapplied. Semi-permanent release agents do not need to be reapplied every cycle of the molding operation and are even more effective when they are not over-applied to the mold surface.
How much release can be achieved before a reapplication is required varies by process, material and method of application? To achieve multiple releases per application, semi-permanent release coatings generally must be applied to a clean, dry surface free of dirt, rust, grime or previous coatings. This allows the release agent to bond properly to the mold and mold tool, increasing the durability and longevity of the coating.
Water or solvent-based
Mold release agents can be water-based or solvent-based, the use of both will depend on the mold maker’s personal preference, factory safety regulations, hazardous material shipping costs, state, local, or federal regulations, and/or the desired mold release Coating Drying Time. Water Based Die Lubricants (WBD) have been used for approximately 40 years. All die-casting machines are of WBD design.
Water-based release coatings generally dry slower than solvent-based release coatings but have fewer health and safety concerns. Water-based release agents are less expensive to ship because they are inherently non-flammable and meet most plant safety goals. Solvent-based mold release coatings dry almost instantly, but present serious health and safety concerns. Fumes from solvent-based mold release agents can be dangerous if the work area is not properly ventilated. Most solvents used in mold release agents are flammable.
Release agents supplier
Huagechemical is a professional release agent supplier provides high quality and effective PU release agent, shoe sole release agent, MSD release agent, wood based panel release agent.
Our product line includes Products include release agent, chemical additives, color paste, paint curing agent. Application areas include PU soles, PU car carpets, wood-based panels, paper (food), metal die casting, paint and glue curing agent products, etc. Our aim is to create value for customers and contribute to society.
If you have any questions about release agents or other products, or would like to seek the latest quotation, please feel free to contact us.