STP ShaliProtek NES 70
A two-component novolac phenolic epoxy that shrugs off acid and alkali attack on steel and concrete at service temperatures up to 90C.
What is it?
A 2K (3:1) novolac-based phenolic epoxy protective coating from STP Limited, engineered for structures exposed to corrosive chemical splash, spillage and fumes at elevated temperature.
Where is it used?
Acid plants, fertilizer units, ammonium sulphate and annealing plants, leather processing, secondary containment, storage tanks, pump pads and trenches across process industries.
Why use it?
It resists a broad band of acids and alkalis, holds up to 90C dry (and passes under-insulation exposure to 230C), and bonds strongly to both steel (>8 N/mm2) and concrete.
How is it applied?
Prime with ShaliPrime Zn Ph on metal or ShaliPrime 2E on concrete, then apply by brush, roller or spray at 100-125 micron DFT after mixing Component A and B at 3:1 by volume.
About STP ShaliProtek NES 70
ShaliProtek NES 70 belongs to STP Limited’s Shalimar family of protective and anti-corrosion coatings, and it is built for one of the harder jobs in a process plant: keeping steel and concrete intact where corrosive chemicals are splashed, spilled or given off as hot fumes. The chemistry is a novolac-based phenolic epoxy, supplied as a two-component system that is mixed on site at a 3:1 ratio by volume. With a volume solids of roughly 75 percent, a single well-applied build lays down a dense, closed film that acts as a chemical barrier rather than a decorative finish. STP positions the NES range for aggressive environments such as acid plants, ammonium sulphate and annealing units, fertilizer plants and leather processing lines, where ordinary bisphenol epoxies would soften or blister.
Within the range, NES 70 is the higher-solids, metal-strong grade. It carries a stated adhesion of more than 8 N/mm2 to steel and more than 2.6 N/mm2 to concrete, so specifiers can use one product across mixed substrates on the same structure. The 3:1 mix, 75 percent solids and 20 L composite pack distinguish it from the concrete-oriented NES 60 (2:1, 62 percent solids, 15 L pack) and the solventless high-heat NES 100. As an authorised STP distributor and applicator serving Delhi NCR and Pan-India, Space Arc supplies NES 70 alongside its correct primers and can advise on specification, DFT and surface-preparation standards for your exposure conditions.
The technical insight
The performance comes from the novolac backbone. A standard epoxy is built on bisphenol-A with two reactive sites per molecule; a novolac epoxy carries multiple epoxide groups along a phenolic chain, so when it cures it forms a much tighter, more highly crosslinked three-dimensional network. That dense network leaves fewer pathways for acids, alkalis and solvents to permeate and attack the substrate, which is why NES 70 passes exposure to 20-25% caustic soda, 20% hydrochloric acid, 10% nitric acid, 30% sulphuric acid, 10% phosphoric acid and diesel/petrol without blistering or wrinkling. The same crosslink density raises the heat-deflection ceiling, letting the film hold at 90C dry and survive under-insulation service up to 230C. Its high volume solids mean the barrier is built with minimal shrinkage and minimal solvent voids, and the priming step (zinc phosphate on steel, epoxy primer on concrete) anchors that barrier to a properly prepared surface so the corrosion protection is continuous rather than pinholed.
Where it is used
- Chemical-resistant lining and coating for steel structures, vessels and equipment in acid and alkali environments
- Protective flooring and coating for concrete exposed to acid or alkali fumes at high temperature
- Secondary containment bunds, trenches and spillage zones in process plants
- Solvent and chemical storage tank areas and pump pads
- Ammonium sulphate, annealing and acid plants where corrosive vapours are emitted hot
- Fertilizer plants and leather processing units with aggressive chemical exposure
- Pipwork and steel members requiring resistance under thermal insulation up to 230C
- Bridges and high-exposure structural elements needing durable anti-corrosive protection
Key advantages
- Excellent resistance to a broad spread of acids and alkalis, including caustic soda, sulphuric, hydrochloric, nitric and phosphoric acids
- High volume solids at 75 percent, building a dense barrier film with low solvent content
- Strong adhesion to both steel (>8 N/mm2) and concrete (>2.6 N/mm2), covering mixed substrates
- Holds service temperature to 90C dry and passes under-insulation exposure up to 230C
- Passes 2000-hour salt spray (ASTM B117) and cathodic disbondment below 8 mm
- Short overcoating window from 6 hours, keeping multi-coat work moving
- Bonds well even at low temperature and humidity, useful for site conditions
- Low-VOC formulation compared with conventional solvented chemical-resistant coatings
Limitations & considerations
- Two-component product with a short pot life of about 1 hour at 27C, so mix only what can be applied in time
- Performance depends heavily on surface preparation to NACE/SSPC standards; immersion service needs a white-metal blast
- Requires the correct primer first (ShaliPrime Zn Ph on steel, ShaliPrime 2E on concrete) to develop full adhesion
- Dry service ceiling is 90C, so continuous immersion in hot concentrated chemicals may need the solventless NES 100 grade instead
- Cure and drying times lengthen in cold conditions, delaying overcoat and handling
- Recommended DFT of 100-125 micron per specification means film build must be checked, as over- or under-application affects protection
Selection & best practice
Start by preparing the substrate to the exposure: clean steel to NACE/SSPC standards, near-white for non-immersion and white-metal blast for immersion service, and make sure both steel and concrete are free of dust, oil, soap and grease. Prime correctly first, ShaliPrime Zn Ph on metal or ShaliPrime 2E on concrete, and let the primer dry fully before topcoating. Stir each component for about five minutes, then combine A and B at 3:1 by volume, working the stirrer slowly up and down to avoid trapping air; allow the mix a short stand and re-stir gently before use. Because pot life is only around an hour at 27C, batch the quantity to your working rate. Apply by brush, or by spray with medium or short-nap squeegee rollers, targeting 100-125 micron DFT and respecting the 6-hour minimum overcoat interval and 7-day maximum recoat window. Keep the material cool, dry and out of direct sun in storage, and use within the 12-month shelf life.
Specifications
| Chemistry | 2K novolac-based phenolic epoxy |
| Mixing ratio (by volume) | 3 : 1 (Component A : B) |
| Volume solids | 75 +/- 2% |
| Recommended DFT | 100 – 125 micron |
| Theoretical coverage | 8 m2/L at 100 micron; 6 m2/L at 125 micron DFT |
| Service temperature (dry) | 90C; under insulation up to 230C (Pass) |
| Pot life at 27C | 1 hour (100 g mix) |
| Overcoating | Minimum 6 hours, maximum 7 days |
| Adhesion | >8 N/mm2 on metal; >2.6 N/mm2 on concrete (ASTM D 4541) |
| Pack size / Shelf life | 20 L composite pack (3:1); 12 months sealed |
Industry use cases
Acid and fertilizer plants
Lines and coats steel and concrete in ammonium sulphate, annealing and acid units where hot acid and alkali fumes attack unprotected surfaces.
Chemical process and storage
Protects secondary containment, solvent storage areas, pump pads and trenches against splash and spillage of corrosive media.
Leather and allied processing
Guards floors and equipment in leather processing lines exposed to aggressive chemical vapours and washdowns.
Insulated pipework and steel
Coats steel members and pipe that run under thermal insulation, where its 230C under-insulation pass resists corrosion-under-insulation risk.
Structural protection
Applied to bridges and high-exposure structural elements needing a durable, salt-spray-tested anti-corrosive barrier.
Frequently asked questions
Is ShaliProtek NES 70 for steel or concrete?
What chemicals can NES 70 withstand?
What is the coverage and recommended thickness?
Which primer do I use with it?
How is it mixed and how long is the pot life?
How does NES 70 differ from NES 60 and NES 100?
How we position STP ShaliProtek NES 70
ShaliProtek NES 70 sits in the middle of STP’s novolac protective range: choose NES 60 for concrete-only exposure where a 2:1, 62 percent-solids film is enough, step up to NES 70 for the higher-solids grade that bonds strongly to both steel and concrete, and move to the solventless ShaliProtek NES 100 for the hottest, most aggressive immersion duties. Pair it with the correct STP primer, ShaliPrime Zn Ph on steel or ShaliPrime 2E on concrete, for full adhesion. Where a specification calls for a named alternative or a globally referenced brand, Space Arc also supplies Fosroc’s equivalent epoxy novolac lining; talk to us with your temperature, media and immersion requirements and we will match the right coating and primer system for the job.
Fosroc Nitocote EN901 — Specify the Fosroc solvent-free epoxy novolac lining when the project demands full pH 1-14 immersion resistance at higher build (400-500 micron) or a globally referenced brand for tanks and containment.
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