The two components rubber Poly 75-75 is a very stiff polyurethane rubber that cures at room temperature (RTV). The Poly 75-75 has a Shore A 75 that is just a bit stiffer than a car tire. The very hard rubber is extremely good with applications as used in the concrete industry. The Poly 75-75 is widely used for making large molds and bulkheads for the prefab concrete. The Poly 75-75 and Poly 75-90 are also widely used in the production of hard rubber parts. The Poly 74 and 75 series rubbers can be used as casting rubber, brush rubber or spray rubber.
There are many additions of additives such as CAB-O-SIL, thinners, accelerators, UV stabilizers and color pigments. In addition to the Poly series products, the PT Flex products are available for the manufacture of rubber parts and any rubber products that may be processed.
Packaging: Set 3 kg, Set 15 kg, Set 54 kg, Set 612 kg
Hardness (Shore A): 75
Mix Ratio: 2A:1B
Working Time (min): 20
Total Cure (hr): 16 hr (demold) / 7 days (100%)
Viscosity (cP): 4.000 (±400)
Tear Strength (N/mm2): 43.25
Tensile Strength (N/mm2): 4.52
Type product: Polyurethane rubber
Application: Mould and rubber parts
Release & Adhesion
Polyurethane casting rubber such as the poly 75-75 adheres when casting on many surfaces such as various types of metal, wood, polyurethane, plastics, epoxy materials, concrete, plaster and many more other surfaces. If release is required on these substrates, release agents such as our Pol-Ease 2300, Lossingsmiddel VL, Pol-Ease 2350 and Pol-Ease 2450 or the other release agents must be used. We always advise to first do a test with the adhesion, release or the suction effect of the rubber on the mold or application. With porous parts made of, for example, wood or plaster, the rubber can be sucked up. You can prevent this by first sealing it with, for example, a pore sealer. This is not a release agent, so if it still needs to be released or is poured with a material that will give you adhesion, use a release agent.
As standard, a polyurethane does bond and silicone does not bond to different materials. This adhesion or no adhesion is not for every material. If you want to generate extra adhesion for, for example, (mechanical) load, we always recommend optimizing this by using an ashesive primer for the different substrates. This gives a good bond for both materials. Before using this adhesive, the surface must be thoroughly cleaned and degreased. Blasting or roughening the surface promotes adhesion with or without a bonding primer.
Casting polyurethane on a material with which no adhesion is created therefore does not require a release agent. Most silicone casting rubbers such as our siliconen Eurosil, Platsil (addition silicone) and SG C-sil (condensation silicone) do not bond with the polyurethane materials. So no separate means is required here. However, it is possible that when you use molds intensively, the releasing effect can become less. Then use the release agent before you start pouring.
Always make a test case before you get started.