PU4232CW is an MDI based polyurethane prepolymer for use as a rubber crumb binder. It has a relatively low viscosity, and its fast cure speed is ideal for play areas. PU4232CW has been formulated as a flexible moisture curing binder for in situ recycled rubber crumb shock pads and EPDM play surface topcoats, which are laid by hand.
PU4232CW meets the requirements of BS7188:1998 when tested on virgin EPDM rubber at 18% binder addition levels.


Available in:
220kg drum
1100kg IBC
22kg Pail


  • Rubber crumb shockpads
  • EPDM topcoats
  • TPV topcoats
  • Rubber threshold ramps

See all applications in our Technical Data Sheet

See all applications in our Technical Data Sheet

How to use

  • Application Temperature

    +5°C until +20°C

  • Substrate Preparation

    Ensure the ground to be coated is well prepared. All loose material should be removed. Ensure the surface is free from contamination such as oil and grease. The surface should also be dry.

  • Mixing

    Mix rubber granules and binder PU4232CW at desired ratio. Ensure the volumetric ratio of binder addition is considered as the bulk density of rubbers will vary. Rubber granules should be dry in order to stop accelerated cure times and foaming of the binder.
    For adequate mixing, a high torque rotary mixer should be used. Rubber and binder should be mixed for up to 5 minutes ensuring all the rubber is coated.

  • Installation

    The product can then be laid out on a prepared surface and compacted using a hand trowel or weighted roller. Ensure an even compaction of the rubber. A release agent should be used on all tools to avoid adhesion of the binder to the tools. Ensure all equipment is cleaner well after use.
    In some cases, particularly low temperatures, D4861 Rubber Crumb Binder Accelerator may need to be added. Further details available on request.



Why does the PU4232CW discolour with exposure to UV?

As will all MDI polyurethanes, they are subject to colour changes during exposure to ultraviolet light. This will not affect the mechanical properties of the binder.

How long does it take for PU4232CW to cure?

Cure time approx. 5-7 hours at 10°C. The cure time will vary depending on the ambient temperature and relative humidity.

What is the recommended ratio of binder to EPDM/TPV for a playground wear layer?

Typically 18-20% binder addition (by weight) is sufficient.

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