ABS, HDPE & PP-like − PR7 SERIES

This range of materials is composed of thermoset polyurethane (PU) resins. This ensures high strength as the polymerisation process allows crosslinking between the chemical structures of the plastic material. Each resin is made of two-component liquid products (polyol and isocyanate), that are mixed together to initiate the chemical reaction.

Thermoplastics are commonly processed through methods like injection molding or extrusion, where the material is melted and formed into specific shapes using aluminum molds. While ideal for high-volume production, these processes can be costly and inefficient during the prototyping phase. That’s where our PR7 SERIES vacuum casting resins offer a practical alternative.

These resins are specially formulated to replicate the mechanical and thermal properties of high-performance thermoplastics such as high-temp ABS, PP, and HDPE. After a prototype is created using Additive Manufacturing, a mold can be produced from the design and used in a vacuum casting machine to form the part. The result is a fully functional component that closely simulates the behavior of extruded or injection-molded thermoplastics—making it perfect for real-world testing or low-volume production, such as vehicle customization or specialized industrial applications. Thermoset resins are more stable and less likely to melt under high temperature exposure.

The PR7 SERIES materials are ranging from semi-rigid to rigid.
– The thermoset vacuum casting resin PR740 simulates a PP or HDPE thermoplastic polymer, with a 590 MPa flexural modulus. It is a quite flexible material, suitable for living hinges applications.
– The thermoset PR777 imitates a Polypropylene or High Density Polyethylene thermoplastic material, with a rigidity of 930 MPa. It is therefore a semi-rigid product, with a high flexibility. It is particularly adapted to larger parts like car bumpers for example.
– The PR700 thermoset PU is a countertype of Acrylonitrile butadiene styrene (ABS) thermoplastic with a high temperature resistance. It has a 1700 MPa modulus with a quite rigid behaviour.
– The PR752 thermoset resin aims to simulate a high-temp ABS product with more stiffness and higher thermal resistance. It is the product with the highest rigidity in this range, with its 2200 MPa flexural modulus.

None of these materials are soft, or try to imitate a thermoplastic elastomer. For softer materials, please check the PU rubber products.

If you are willing for stiffer plastic materials, several of these products can be reinforced with our SYNFILL G glass fiber filler. This fiber increases the materials properties making them incredibly stong, with a high heat resistance. The PR752 with added glass fiber filler is the closest material to Nylon (PA thermplastic) that SYNTHENE has in its range.

All these materials share the same isocyanate “PR7 SERIES ISO”, making them incredibly gentle on silicone moulds.

The tooling material is therefore preserved as much as possible, with a non-aggressive urethane resin.

Depending on the shape of the part and the silicone-rubber brand used, one can expect to cast between 30 to 60 parts in one single mould. This obviously leads to a significant saving of both time and resources, since the same silicone mould can be used for multiple reproductions without premature wear. In practice, this reduces the need to manufacture new moulds as frequently, which streamlines production and lowers costs. In addition, because the moulds remain in better condition throughout their lifespan, the surface finish of the cast parts is more consistent, requiring less rework or post-processing. The result is a more efficient workflow, with reduced labour on mould fabrication and finishing, and a faster turnaround from concept to final product.

Altough these 4 polyurethane materials have been particularly formulated for the vaccum casting application, the PR700 and PR777 are also adapted for a use in RIM machine or two-component injection machine.

Yes, these materials can also be hand-casted. Please refer to the Technical Data Sheets of the products.

The PR740, PR777, PR700 and PR752 are all adapted for warm temperature exposure, with very limited risk of melting or deterioration. It is reguarly used in the automotive industry.
The PR740 has a 96°C Heat Deflection Temperature, and it goes up to 150°C with the PR752. This value can be increased to 177°C with the use of the fibreglass filler SYNFILL G.

The PR740, PR777, PR700 and PR752 benefit from a very High mechanical resistance. It is widely used in the automotive industry for prototyping and short series.

To get optimal properties, we recommend to carry-out a post-curing in an oven, as indicated on the TDS. The thermal treatment will help to reach the maximum characteristics of the material.

All of these resins share a high level of thoughness. Depending on the requested properties (abrasion resistance, impact resistance, flexibility, tensile modulus of elasticity…) – please refer to the TDS of the material or contact our Team to get technical support in the selection of your resin.

The PR700 is available in black colour only.

The PR740 and PR752 are transparent amber and can be pigmented.

The PR777 is milky/beige and can be coloured.

Please note: all PR7 SERIES materials will gradually darken when exposed to UV light. This colour shift is purely aesthetic and does not affect the mechanical or physical properties of the resins. The materials remain chemically stable.

For crystalline colourless transparent product like epoxy, and with full UV resistance properties, please check the PC & PMMA-like vacuum casting resins of the range.

Several tests have been realized on conductivity.

Data on thermal conductivity is available for PR700, Glass-filled PR700, PR752 and PR777.

Regarding dielectric properties, a test report can be provided for PR740 and PR777, including electric strength according to DIN EN 60243-1:2014-01 and Comparative Tracking Index (CTI) according to DIN EN 60112:2010-05.

Please contact our Team for more information.

The 4 vacuum casting resins of the PR7 SERIES range have been tested in different situations toward chemical aggressions. Becuase of the polymerization process and the chemical structure of these thermoset materials, they all perform very well regarding chemical resistance. They have been immersed in sea water but also in various aqueous solutions, acids and solvent. They have been tested in engine environment to check their suitability for automotive applications.

All these tests, as well as our long-term customer experience, prove that these polyurethane products are suitable for the making of fully functional automotive prototypes.

Please contact our Team to get more details about the testing conditions.

The PR7 SERIES is engineered for advanced prototyping and limited-series production, particularly where the mechanical and thermal simulation of thermoplastics like HDPE, PP, and ABS is required.

These resins are widely adopted in the automotive industry, to make car parts bumpers, interior trim parts, parts in contact with engine-fluid environment, rearview mirrors etc.

They can also be used in the aerospace industry, Medical and Defense fields. Some of our customers use them for consumer electronics, Industrial machinery and technical assemblies, where mechanical resilience and thermal stability are also essential.

The flame retardancy properties have been tested according to the IEC 60695-11-10 A: 2015 horizontal burning test for the PR700, PR777 and PR752.

For a self-extinguishing material with a UL 94 V0 fire resistance, please check the PRA794 material.

For a FAR25 certified resin, please check the PRA730 resin.

The PR700 is without a doubt SYNTHENE’s absolute best-seller resin. It is popular around the globe for its user-friendliness, low aggressiveness to the silicone moulds and high performance for prototype-making.

The PR777 is also widely appreciated for its easy 1:1 mixing ratio, good flexibility and colourability.

They can also be used to replace plastic-injection process in the manufacturing of short run series for plastic parts.

Some resins in the PR7 SERIES, particularly PR700, naturally release a noticeable odor during the casting process. This characteristic smell is related to the resin’s chemical formulation, which is designed to deliver high performance. The odor diminishes significantly once crosslinking is complete and the part is fully cured.

It is important to note that a strong odor does not necessarily indicate toxicity. The PR7 SERIES has been carefully formulated to balance performance with user safety. All materials in this range have a mercury-free catalyst and contain no substances classified with “skull-and-crossbones” labeling.

For users who are more sensitive to odors, we also offer a “Low Smell” version of PR700, called PR700 LS, which provides the same mechanical properties with improved user comfort.

Our Team is available to guide you and arrange trials if you’d like to evaluate this user-friendly alternative.

All SYNTHENE materials comply with the REACH regulation.

The PR7 SERIES PU resins have an extraordinary long shelf life of 18 months from production date.