SUNEPOXY 368

The epoxy resin used in construction is typically a light amber coloured liquid about the viscosity of a heavy motor oil. By itself epoxy resin is not an adhesive. It must be combined with a hardener or curing agent, typically an amine or a polyamide. Once combined by thorough mixing, a chemical reaction begins and as it is taking place, individual molecules of the resin and hardener from chemical bonds or linkages. These linkages are very strong and occur not only in a linear direction, but in three dimensions – respond to as ‘cross-linking’. When epoxies fail to cure properly, due to poor curing or off-ratio proportions for example, the structure of this cross linking is poor. Consequently the material does not harden completely and may seem rubbery, soft or tacky.


Properties

An epoxy with the lowest viscosity was selected for injection all these days. However, to-day epoxies are being formulated with viscosities close to that of water (one centipoise). These work well in thin cracks.

ASTM Type I
Sunepoxy 368
Viscosity, Centipoise max 2000
400 – 500 cp
Get time, minutes 30
45 – 60 minutes
Bond Strength min (psi) 1000
17 N/mm2 (2500 Psi)
Compressive Strength
7 days min (psi) 8000
68 N/mm2 (10000 Psi)
Tensile Strength
7 days min (psi) 5000
34 N/mm2 (5000 Psi)



Ratio

Based on the formulation, specific amounts of resin and hardener are required for a full reaction and proper cure. SUNPOXY 368 has a 3:1 volume based ratio.


Mixing

Mix one batch at a time using a bucket and drill (connected to a stirrer). The drill speed is to be low 300-400 rpm. Use cage type mixing paddles. Keep the mixing paddle below the surface of the material as much as possible Half-way through mixing, stop mixing and scrape the mixing paddle and the side and bottom of the bucket or transfer the contents to another bucket and complete the mixing. Mix injection resin for three minutes. Do not over mix with high-speed drill, this can generate excessive heat.


Surface capping

Formulations of epoxy that easily permit the paste to be applied to the surface of the crack to contain the injected resin, are generally used. It would be advantageous to use formulations that permit crack injection as soon as one hour after capping.


Instruction for use

Remove loose, disintegrated and porous concrete at cracks and joints and repair the same either with epoxy mortar or polymer modified mortar. Thereafter drill the injection holes to the depth of two to four inches. The distance of injection points depends upon the cracks, extent of damage and the dimensions of the structural elements. Fix the nipples and clean all the loose dust particles from the cracks and holes by blowing compressed air through at the nipples in succession. The above mixture of epoxy and hardener can be injected by means of suitable pump at pressure of 50-100 psi.


Packing

SUNPOXY 368 is available in 20 kg, 5 kg and 1 kg packing.

HARDENER is available in 5 kg, 1 kg packing.


Shelf life


Twelve months when stored in original closed container.