Chemical Resistance Testing on Epoxy Paint Samples by Concentration

“Does this epoxy resist acid X?” is a question missing its data. The correct answer always comes with three variables: concentration, contact time and temperature. The same chemical, dilute at room temperature, may cause no harm, but that same substance at high concentration, high temperature or under continuous immersion for many days may destroy the coating. This article explains how to read a chemical resistance table for epoxy paint samples by concentration — as a general guide to reading results. It does not publish any Kadier chemical resistance table and does not contain any line of the form “system X resists chemical Y”, because the parameters for each individual coating system are only found in that system’s manufacturer’s TDS and official chemical resistance table; every general reference range below carries the same note: a general reference range only — the specific product’s TDS decides.

Illustration: a gloved hand handling a test sample in a laboratory. Source: Pexels, by Tima Miroshnichenko. Illustration only — not a Kadier test sample or test result.

1. Why is “resists acid” an incomplete question?

• Concentration: the same chemical at 5% and at 50% concentration can give opposite results. A chemical resistance table that does not state concentration is not enough to decide on.
• Contact time: a splash wiped off immediately is very different from occasional ponding, and very different again from continuous immersion for many days.
• Temperature: 25 °C is different from 60 °C. Higher temperatures usually make a chemical attack the coating faster and more strongly.
• Concentration rising as it evaporates: a dilute solution spilled on a floor that then dries by evaporation becomes progressively more concentrated on the floor surface — a point often missed, especially in wash areas and dry stores.

In other words, a bare word “resistant”, with no concentration, time or temperature attached, is not a complete technical statement. Related article on the table by acid concentration: Chemical Resistance of Epoxy Floors: Table by Acid Concentration.

2. Three main test methods and when to use each

Method	How it works (general framework)	Use when
Spot test — ASTM D1308, ISO 2812-4	Apply the chemical to one spot on the coated sample, cover or leave open for an agreed time, then assess. As described in ASTM D1308, an open spot test is usually carried out at 23 ± 2 °C, with common contact intervals of 15 minutes, 1 hour or 16 hours (or as agreed); assess immediately after wiping clean, and possibly reassess after a recovery period.	Quick screening for small spills, splashes and short contact.
Immersion test — ISO 2812-1, ASTM D543	Immerse the sample (often 50% of the test panel in immersion spot testing as described in ASTM D1308) in the chemical for the duration of the test, then assess.	Simulating tanks, long ponding and continuous contact.
Severe test (Atlas cell, autoclave)	Immersion under pressure and at temperatures above ambient.	Severe environments; this article only names it, does not go into detail, and results of this type do not automatically carry over to ambient conditions.

After contact, changes assessed include: discolouration, gloss change, surface softening, blistering, swelling, peeling and loss of adhesion. A short-term spot test result must not be converted into a long-term immersion commitment, and vice versa.

3. How to read one row of a chemical resistance table

Manufacturers’ tables usually rank in forms such as “good resistance / limited resistance / not resistant” — the level names differ by manufacturer, and when quoting they must be quoted exactly as the source names them, not converted into a separate scale of your own. Whatever the level stated, one row of a table is only enough to decide on when read together with the table’s notes:

1. Which chemical, at which concentration (the actual diluted concentration in use, not the concentrate concentration on the label)?
2. What was the test temperature?
3. What was the time and form of contact (splash, occasional ponding or continuous immersion)?
4. What minimum film thickness and fully-cured conditions must hold for the result to be valid?
5. Which exact product family does the table apply to — do not apply one epoxy family’s table to “epoxy in general”.

A table that does not state all three variables — concentration, time and temperature — is not a sufficient basis for choosing a system for that area. Note also: chemical resistance only holds at the minimum film thickness and after the coating has fully cured; strong chemicals or high temperatures may require a specialist system (for example a novolac system or a specialist primer) — this must be checked against the manufacturer’s table, not concluded on your own.

At a general qualitative level, epoxy is often mentioned for good resistance to oils, dilute alkalis and many cleaning solutions, while strong solvents, concentrated acids and high heat are areas needing separate verification. This sentence is only directional — every decision for a specific project must be written in the form “needs verification against the manufacturer’s table”, with no absolute “resists / does not resist” list unless the manufacturer’s specific table is in hand.

4. Four-step check before choosing a system

1. List the chemicals actually in use: chemical name, actual diluted concentration, temperature, frequency and form of contact (splash, ponding or immersion). Do not forget cleaning chemicals and disinfectants — they are also “chemicals” that must be listed, not only production chemicals.
2. Check against the right product family and the manufacturer’s own table: check each row of the table against all three variables — concentration, time, temperature — and the minimum film thickness.
3. For unfamiliar or critical chemicals, test a sample first: request a coupon test at the exact concentration, temperature and form of contact in real use before wide-area application.
4. Record it and put it in the acceptance file: the chemical list, the comparison table and any sample test results (if any) should accompany the acceptance record — see the acceptance and warranty page — so that later operation and cleaning follow the conditions already checked.

5. When is a real sample test mandatory?

• The chemical is not in the manufacturer’s table, or is in the table but at a different concentration, temperature or time from real use.
• Continuous immersion, long ponding or high temperature, while the table only has short-term spot test results.
• Areas cleaned daily with strong chemicals, or with hot wash cycles — where the actual concentration on the floor may be higher than the initial diluted concentration due to evaporation.
• Any case where a wrong decision would mean redoing the whole floor area: testing one small sample costs far less than applying over a wide area and only then discovering it does not resist.

Frequently asked questions

Is a table stating “acid resistant” enough to choose a coating for an acid area?

Not yet. You must know which acid, at which concentration, for how long, at which temperature, and what the minimum film thickness is. Missing any of these, you should not decide yet.

If a spot test passes, is long immersion certainly passed too?

No. A spot test simulates short contact; continuous immersion is a harsher condition and needs its own immersion result before concluding.

Do cleaning chemicals need to be on the chemical list?

Yes. Cleaning and disinfecting agents contact the floor daily, repeatedly, and are one of the common causes of early floor deterioration if not checked from the start.

Why does this article have no Kadier chemical resistance table?

Because a chemical resistance table named for a coating system is only valid when it is that system’s manufacturer’s official table, stating concentration, temperature, time and form of contact. This article is a general guide to reading tables; the specific table is checked when the customer sends their actual chemical list.

Contact

Send your chemical list with actual concentrations, temperatures and frequencies so Kadier can check the chemical resistance table of the suitable system, via the quote page or the contact page (hotline/Zalo 0899355489, WeChat wxid_95o54joujyrr12). Also refer to the RollCoat, LevelFlow, StatGuard and AquaBase systems to see each system’s function before sending your chemical list.