An Introduction to Anchor Resins

13 May 2021

An Introduction to Anchor Resins

The resins used for anchoring purposes are usually composed of several ingredients; the main ones are listed below:

A Polymer, which gives the basic properties of the resin and binds it together (like cement in concrete)

• One or more monomers - these liquids are used to give a workable product.

Mineral additives, to give extra strength to the cured resin – like aggregate in concrete.

• A Curing agentor hardener; mixing this in starts the chemical reaction to harden the resin.


Other additives can be included to give the resin the correct consistency, colour etc.

For many years, bonded resin anchors were produced with a Styrene monomer. Although Styrene is still widely used for injection anchors, concerns over safety, both in terms of health (it is classed as harmful) and transportation (it is flammable) later led to the introduction of ‘Styrene-Free’ products; the difference being the liquid Monomer used. These variants reduced the health and safety classification, however at a slightly increased cost (it is worth noting that, when installed in accordance with the manufacturers recommendations, including precautions for health and site protection, Styrene based resins offer a negligible health hazard).

Anchor resins are available in three different formats, detailed below:

Glass Capsule (Polyester and Vinylester) – A glass capsule that contains the resin and a vial of hardener.

The glass capsule is placed in a pre-drilled hole and the components mix and set once a stud or socket is driven into the hole via a hammer drill.

Plastic cartridge – A cartridge, containing the resin, hardener and various other components, depending on the resin format. The resin and hardener are kept separately in the cartridge, until delivered through a mixing nozzle via either a specialist gun (for 380ml and ‘side by side’ tubes) or a standard silicone gun (for 300ml and smaller tubes).

Foil Pack – The foil pack is a resin dispensing system, providing a packaging solution. As well as it being very light weight, it offers a huge reduction on overall waste. Similar to the cartridge system, the resin components are kept separate in the foil tube until delivered through a mixing nozzle.


Popular types of resin


Polyester (e.g. Rawlplug R-KF2)

  • Economical resin for medium duty loads in non-cracked concrete.
  • Can be used in damp conditions and under water applications.
  • Small edge and space distances.

Polyester - styrene-free (e.g. Rawlplug R-KEMII)

  • The most popular general-purpose resin.
  • Intended for medium duty fixings in most substrates.
  • Low odour can be used indoors.
  • Product with wide spectrum of use in the medium load capacity area.


Vinylester hybrid resin (e.g. Rawlplug R-KER-II)

  • The most common type for construction.
  • Intended for high load capacity.
  • Intended for use with threaded rods in concrete, including in cracked concrete (ETA option 1).
  • Suitable for use in low temperatures (a winter version is available which works down to -20°C).
  • Good curing time (approx. 1 hour at 15°C – for wet concrete, the curing time should be doubled)
  • Winter (fast cure) and Summer (slower cure) variants are available.
  • Winter version can be used in warmer temperatures speed up the curing time.
  • Suitable for use in dry and wet substrates as well as water filled holes.

The above resin types are available in glass capsule, plastic cartridge and foil pack variants.

Pure epoxy resin (e.g. Rawlplug R-KEX II)

  • The most suitable for construction, and where deep anchorage is required.
  • The strongest resin in the epoxy resin range.
  • For use in concrete (including cracked concrete) and can be used with post installed rebar.
  • High depth anchoring for rebars (up to 2.5 mtrs)
  • High Chemical resistance
  • Minimal shrinkage makes it an option for use in diamond-drilled holes and over-size holes
  • Good working time (up to 30 mins at 20°C) for easy installation of metal components

To view our range of anchor resins and masonry fixings, click here.

Or, to get some more information and discuss your needs, contact us.

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