Synfill G Fibreglass

The SYNFILL G glass fiber filler can be added in SYNTHENE’s vacuum casting polyurethane resins. There PUs are thermoset resins that aim to simulate various types of common thermoplastics.

The cross-linking nature of the chemical reaction entail a chemical bonding that gives a high strength and stability to the material. Adding fibreglass increases the mechanical and thermal properties, resulting in a reinforced plastic polymer.

The vacuum casting technolgy consists of casting a two-component liquid PU into a silicone mold, in order to replicate a part. The molded material can be used as a fully functional prototype.

Several vacuum casting resins in our range have been tested with SYNFILL G:

– The PR408 imitating a regular Acrylonitrile butadiene styrene (ABS) thermoplastic

– The high-temperature resistant ABS-like PR700 and PR752

– The Polypropylene countertype PR777

With the addition of glass fibre filler, these thermoset polyurethane resins turn into fiber reinforced plastics. This process creates composites.

The casting process remains the same as the polyol and the isocyanate are casted into a rubber-silicone mold, and chemically react with each other.

The glassfibre should always be premixed with the isocyanate component. If the product is mixed in a vacuum casting machine, mix the SYNFILL G and the Isocyanate in the lower cuper, and place the Polyol component in the upper cup. Degas for 10 minutes, with agitation in the lower cup. Then stop the agitation and pour the Polyol into the Iso + glassfiber mix.

We deliberately supply Synfill G as a separate component, allowing you to tailor the filler rate to the performance characteristics you need.

This also avoids sedimentation and storage issues. We want to make sure our customers can get the best of our materials.

Better flexiliblity, more user-friendliness!

The recommended rate depends on the resin and the properties you want to achieve:

• PR408 → Our tests show that 25 % filler gives the best balance of mechanical and thermal performance.

• Other resins → We provide data for 15 %, 20 % and 25 %, so you can choose based on the stiffness, HDT, and flexural strength required.

We do not recommend to exceed 25% of filler rate in the material so we make sure the final part is not brittle.

For precise recommendations and performance data, please refer to the Technical Data Sheets (TDS) of each resin system.

In case of doubt, our Team will be glad to support you.

The addition of SYNFILL G in our plastic materials increases the rigidity of the material. The more additive, the stiffer the product will be. The hardness is slightly impacted, but the flexural modulus rises subsequently. This results in a higher flexural strength and a stronger PU molded part.

For instance, the PR700 has a 70 MPa maximum flexural strength when unfilled, and it can go up to 105 MPa with the addition of 25% SYNFILL G.

The addition of glass fiber filler has a great impact on the heat resistance of the materials. The resins are more likely to withstand high temperatures when the SYNFILL G is added.

For example, with PR752 it is possible to reach a 177°C Heat Deflection Temperature (HDT), and the material does not melt when exposed to high temperatures.

Yes, the glass fiber filler makes the material slightly more conductive. Tests have been realised on the PR700 with a 20% rate of filler.

Contact us to get the more information about the test report.

Vacuum casting resins are designed to replicate the behavior of common thermoplastics such as ABS, PP, or HDPE.

When glass fibers (GF) are added during the moulding process, the cured parts gain higher rigidity and toughness, making them significantly stiffer.

Reaching the rigidity level of nylon (PA) can be challenging, but the addition of SYNFILL G brings the material closer to the performance of filled-PA, offering a good compromise between stiffness, toughness, and ease of processing.

Yes. These urethane materials have been formulated to be compatible with pigments, so it is possible to add solvent-based tints to the product.

For best results:

– Pre-mix the pigment with the polyol component.

– Pre-mix the fiberglass filler with the isocyanate component.

– Do not exceed 2–3% pigment by weight, as higher amounts may negatively affect the resin’s formulation and final properties.

The addition of glass fiber filler naturally increases the viscosity of the material. However, our formulations are carefully designed to preserve user-friendliness during casting, ensuring that silicone moulds can still be filled properly.

All viscosity values and variations are clearly detailed in the Technical Data Sheets (TDS) for each filler level, so you can select the most suitable ratio for your application.

In general, literature shows that the addition of fiberglass tends to improve the chemical resistance of materials. However, this has not yet been specifically tested on our resins with SYNFILL G.

Many of our unfilled products already demonstrate excellent resistance to chemical aggressions. For example, the PR7 SERIES has proven particularly robust and is even suitable for demanding engine environments.

Yes, the PU thermoset resin becomes a particle-reinforced composite with the addition of SYNFILL G. The polyurethane resin is therefore considered as a matrix as the glass fibers are mechanically bonded to the polymer.

Glass fiber fillers in combination with polyrethane resins are mostly used in industries where reinforcing resins is important.

This applies to aerospace, automotive, consumer electronics or even in the Defense industry. Using glass fiber in the fabrication process allows to get more specific material properties that are added to a regular unfilled resin: higher rigidity, better thermal performance, higher chemical resistance…

Tests have been carried out with carbon fiber.

If you have any requirement regarding the addition of fillers to our materials, our Team will be glad to support you.

Even if PR700 and PR777 can be used to fill molds with a RIM-machine, we do not recommend to add SYNFILL G in the process.

Because of the abrasive nature of the filler, this process would be likely to cause damage to the pumps of the machine

We recommend using a vacuum casting molding process as in the TDS.