Release agents for composites
Composite release agents are chemical products applied to the mold to make part extraction easier and to protect it from the highly abrasive resin and mineral-filler mixes typical of this industry. At AITANACHEM, we have developed a complete release system for composite manufacturing, based on high-performance water-based semi-permanent release agents. A single application allows multiple consecutive releases, with minimal transfer to the part and no build-up in the mold. They are suitable for both metal and polymer molds (epoxy, polyester).
The demolding challenge in composite manufacturing
Composites have a particular feature that shapes the whole demolding process: in this industry the mold is the most expensive investment, and the mixes of resin with mineral fillers are highly abrasive. Every release wears down the mold surface. This is why a composite release agent has to achieve two objectives at once:
- Make the part easy to extract, providing the necessary lubricity and non-stick properties, even in molds with complex geometries.
- Protect the mold and extend its service life, forming a flexible yet highly resistant barrier against the abrasive resin mix.
Our release agents are based on high-performance polymers that create this protective barrier. They also seal the mold’s anchor points — micropores and other surface irregularities — where the part tends to grip. By eliminating these anchor points, the safety margin against sticking increases and demolding becomes easier and more reliable. To formulate this type of product correctly, both the wear of the release film caused by the abrasiveness of the mix and the complexity of the mold must be assessed in advance.
Composites and application sectors
Our release agents are designed to demold the most common resins and materials in the composite industry: polyester, epoxy, vinyl ester, gelcoat, as well as polyethylenes, polypropylenes, polyamides, phenoplasts, aminoplasts and vinyl and acrylic derivatives. They cover a wide range of applications:
- Solid surface and solid-surface parts, such as shower trays and countertops.
- Fiberglass and carbon fiber, including technical parts for the aerospace and high-performance automotive sectors.
- Gelcoat-laminated parts and structural composite components.
- Technical panels and parts made of epoxy or polyester resin.
- Large-format parts and molds with complex geometries.
What a composite release agent must deliver
If you are evaluating suppliers for your composite process, these are the criteria that make the difference in this industry:
Mold protection against abrasion
This is the requirement specific to composites and the most important one in economic terms, because the mold is the most expensive investment in the plant. The release film must resist the wear of a highly abrasive resin and mineral-filler mix without breaking down after each cycle. A release agent that protects the mold directly extends its service life and reduces the cost per part.
Zero transfer to the part
The release agent must not transfer to or contaminate the molded part. This is achieved when the product bonds strongly to the mold rather than to the part. Low transfer is essential for parts that will be painted, varnished or bonded, and it avoids subsequent cleaning of the part.
Sealing of anchor points
Micropores and small surface irregularities in the mold are points where the part grips and demolding becomes harder. A good composite release agent seals these anchor points and creates a homogeneous surface, increasing the safety margin against sticking, especially in molds with complex geometries.
High number of releases and easy application
A semi-permanent release agent allows many consecutive releases after a single application, as opposed to traditional continuous-application systems. Added to this is ease of application, no small factor when working with the complex-shaped molds common in the composite industry.
Water-based release agents for composites
At AITANACHEM, we encourage our customers to use water-based release agents. Developments in this technology over recent years have brought it on a par with solvent-based release agents in terms of performance, and its advantages make it increasingly sought-after: healthier and safer working environments, non-flammable behaviour, and lower transport and storage costs, as it is not classified as dangerous goods (ADR). You can see the full comparison between technologies in our guide to mold release agents
Mold preparation and maintenance
The performance of any release agent depends on the condition of the mold. A composite mold with accumulated residue reduces the number of releases per application and worsens the finish of the part. Before implementing a semi-permanent system, we recommend that you:
- Carry out a thorough cleaning using mold cleaners suited to the type of residue.
- Apply a sealer as part of mold treatment and maintenance : pre-sealing closes the micropores and noticeably improves the performance of the release agent.
Frequently asked questions about composite release agents
Why is the release agent so important in composite manufacturing?
Because in the composite industry the mold is the most expensive investment, and the mixes of resin with mineral fillers are highly abrasive and wear it down. A good release agent does not just make part extraction easier: it protects the mold surface and extends its service life, which reduces the cost per part. That is why it is best understood as an investment in protecting the mold, not as a mere consumable.
Does the same release agent work for polyester resin and epoxy?
Our release agents are designed to demold the most common composite resins — polyester, epoxy, vinyl ester and gelcoat, among others — as well as various technical polymers. That said, each resin and each mold geometry has its own particularities, so we analyse your process before recommending a specific formulation.
Do you have release agents for carbon fiber and aerospace parts?
Yes. We work on the demolding of carbon fiber parts and high-performance structural composites, including aerospace and high-end automotive applications. In these parts, the absence of transfer and the protection of the mold are especially critical given the high value of each component. As with all other applications, we analyse your specific process before recommending a formulation.
How does the release agent prevent transfer to the part?
The key is adhesion: our semi-permanent release agents bond strongly to the mold rather than to the part, so no product is transferred to the composite surface. The part is then ready for subsequent painting, varnishing or bonding, with no intermediate cleaning step.
How many releases can you get from a single application?
It depends above all on the geometry of the part, the type of resin and the condition of the mold, so we do not give a fixed figure: it would be misleading. The real difference lies in the technology: a semi-permanent release agent allows several consecutive releases after a single application, whereas traditional continuous-application systems require reapplication on every cycle. We determine the specific figure for your process during the trial phase at your premises.
How should a water-based release agent be applied correctly?
Application determines a large part of the performance. Water has a high surface tension, so spraying must be very fine: the technique involves several light passes rather than one thick coat, so that product does not accumulate or form droplets on the mold. Applying more product does not guarantee better release — quite the opposite. We explain this step by step, video included, in our guide on how to apply water-based release agents
We adapt the release agent to your composite process
The type of resin, the mineral filler used, the geometry of the mold and the required finish completely change the requirements of the release system. That is why, rather than selling an off-the-shelf product, we have a highly qualified technical team that analyses your process and sends you the release agent that best suits your needs so that you can test it at your premises. Always with our technical support throughout the trial phase. Our long track record in polymer-matrix composites allows us to adjust the formulation to the specific characteristics of your production.
Are you experiencing mold wear, transfer to the part or sticking on complex geometries?
Get in touch with us and we will look at your case with no obligation.
👉 Looking for general information on release technologies, types of release agents and other application sectors? Take a look at our complete guide to industrial mold release agents