Light weight mineral fillers (LWF) for composites
Our light weight mineral fillers (Low Weight Fillers – LWF) have been specifically formulated to replace traditional mineral fillers (such as calcium carbonate or dolomite), achieving a reduction in the density of the final composite part from 2.3 g/cm³ (typical with standard fillers) to values between 1.0 and 1.4 g/cm³ depending on customer needs. This is a unique, market-proven technology that is implemented on existing production lines with no additional investment in machinery. At AITANACHEM we formulate and adjust these light weight mineral fillers to each customer’s target density to optimize the balance between weight, performance and cost.
What are light weight mineral fillers (LWF)?
Light weight fillers, or Low Weight Fillers (LWF), are combinations of minerals specifically formulated to lighten composite products while keeping their physical-mechanical properties fully intact. While a standard dolomite-based formulation based reaches densities around 2.3 kg/litre, with LWF technology we manufacture parts with densities of around 1.2 kg/litre —and we are working to approach 1.0 kg/litre—. The result is a mineral filler capable of reducing final product weight by up to 40%, delivering the same performance and quality as a conventional piece.
Unlike other market solutions that introduce untreated particles that weaken the mass or lower the heat deflection temperature (HDT), our weight reduction technology incorporates surface-treated, silanized mineral fillers. This ensures a balanced particle size distribution, excellent thixotropy, and perfect chemical bonding with the resin.
How our weight reduction technology works
Our LWF technology generates a controlled microbubble structure within the polymerized mass, which lowers the density of the composite. For this reason, the outer surface of the part must be coated with a gelcoat; to complete the technology, we have developed high-quality ISO-NPG gelcoats covering the entire RAL colour range and the most demanding slip-resistance classes for sanitaryware products. Its main features are:
- Compatible with all resins: polyester, acrylic and vinyl ester.
- Adjustable density: we adapt the target density to each customer’s optimum profitability point.
- No changes to the production line: manufacturers working with dolomite adapt their existing lines with no need to invest in machinery.
- Concentrated version (LWF Concentrate): allows combining our filler with local filler (e.g., at 50%) to reduce freight costs; in this case, we analyse the customer’s local fillers in our laboratory beforehand to design the proper formula.
Competitive advantages of our light weight fillers
Developing lightened formulations requires strict control over reaction kinetics and rheology to prevent filler migration or density-based separation. Our low weight formulations offer proven operational advantages:
- Lower shipping cost: weighing significantly less (up to 40%), many more pieces fit in a truck or container, a decisive factor for selling in export markets.
- Easier handling and assembly: a lighter product simplifies both factory production and final installation.
- Higher productivity: by injecting a much less dense mass into the mould, our customers increase their daily output by up to 15-20% without changing their production process.
- No loss of quality: parts keep their physical-mechanical properties and easily pass certification testing under European (EU) and British (UKCA) standards in sanitaryware applications.
- Superior thermal shock behaviour: when combined with suitable resins, parts moulded with our LWF fillers pass the most demanding thermal cycling tests (CE marking), recording less deformation and warping than traditional dolomite formulations.
- Reduced finishing work: thanks to a balanced viscosity and mixture homogeneity, the resulting surface requires less post-processing and polishing effort, presenting a more uniform surface finish.
- Aero-thixotropy and zero osmosis: surface treatment minimizes in-line repairs to below 2% and eliminates future gelcoat chipping or osmosis issues.
Light Weight Filler Applications
Our composite weight-reduction technology is currently applied across various industrial sectors where weight is a critical competitiveness factor. We develop the most common applications in detail on our blog:
Shower trays
This is the application for which this technology was born. It provides a drastic mass reduction in large-format pieces while maintaining excellent planar rigidity and thermal shock resistance. Numerous shower tray manufacturers using our low-density technology have certified their products in independent accredited laboratories under European and British standards. Discover how to reduce the weight of shower trays.
Bathtubs
Weight reduction is even more decisive in a product that usually exceeds 125 kg. With our LWF technology we can manufacture bathtubs that are approximately 40 kg lighter than those currently on the market — far easier to handle and install. In addition, in demanding thermal shock tests, LWF-manufactured bathtubs exhibit less deformation at the end of the cycles than standard dolomite bathtubs, and require less finishing work: the surface is more uniform and polishing is much easier. We will shortly publish a specific article on bathtub weight reduction based on testing results.
Polymer concrete
Low weight technology is also applied to polymer concrete parts, where lightening the product opens up new possibilities for design and transport. Our LWF technology enables the manufacture of much lighter bulky parts. Read our article on polymer concrete weight reduction.
Technical support and custom formulations – Concentrated Light Weight Fillers
Every project starts from a different target density. Our technical department adjusts the light weight filler formulation to each customer’s optimum profitability value. For our export customers with long-distance destinations, we offer the Concentrated Light Weight Filler range. This technology makes it possible to ship only the technical fraction, so the customer adds the coarse mineral fraction locally (such as dolomite). In this way, we achieve freight savings of up to 50% without sacrificing the mechanical performance of the final product. When opting for the concentrated version of our light weight filler, our laboratory technicians analyse local mineral fillers to integrate them into the formula while maintaining final product properties. If you are considering transitioning your production to light weight or want to develop a new application, contact us.
Frequently asked questions about light weight fillers (FAQ)
How much weight can be reduced with light weight fillers?
Currently up to 40% compared with a conventional formulation. In practice, we move from densities around 2.3 kg/litre (dolomite) to densities of around 1.2 kg/litre, adjustable according to product or customer’s needs.
Are mechanical properties lost when reducing weight?
No. LWF technology keeps physical-mechanical properties and final product quality completely intact; only density changes. In most cases, based on customers’ tests, the physical-mechanical properties of products made with this technology are superior to those made with dolomite or calcium carbonate fillers.
Does the production line need to be modified?
No. It is an immediate-implementation technology: manufacturers working with dolomite adapt their existing lines without any additional investment in machinery.
Why does it require a gelcoat finish?
Because density reduction is achieved through a microbubble structure; gelcoat seals and protects the outer surface. We have developed specific ISO-NPG gelcoats for this technology.
Which products can it be applied to?
Although its use became popular in shower trays, today it is successfully applied in the manufacture of bathtubs, countertops, architectural polymer concrete elements and industrial parts, where weight savings and ease of transport are decisive key competitive factors.
Want to Test Light Weight Technology at Your Premises?
Our technical team formulates custom mineral blends for your production line. We analyse your current process and supply test samples tailored to your needs. For any inquiries about weight reduction in your products, contact us.
Light weight fillers are just one of the technologies within our wide offering of mineral fillers for composites. If you want to learn about the other families (dolomites, reinforcing fillers and ATH) and how to choose the right filler, see our complete guide to mineral fillers.