YLH-6005 is a low viscosity epoxy hardener built on a nonylphenol-free modified polyetheramine with AHEW 95 g/eq and 250–450 cps at 25 °C. It carries 50 phr against an EEW 190 resin, and this report ranks it here against four in-house grades on gel time, colour, hardness build and flexural strength.

Figure 1. YLH-6005 as supplied: a light yellow liquid in the 250–450 cps band, the viscosity that keeps a self-levelling floor mix workable.

1. Introduction

A contractor choosing between five amine hardeners is choosing which property to give up. YLH-6005 gives up colour and some flexural strength to gain the fastest gel in the low-viscosity group: 23 min against 30 to 50 min.

Four modified amine hardeners share the 250–12000 cps envelope and one test reference, a liquid bisphenol A resin of EEW 190, so published numbers read across without extrapolation.

Scope stops at ambient cure: flooring and electronic potting. Laminating and anhydride chemistry sit outside.

2. Materials and Methods: Identification and Test Basis

2.1 Product Identification and Published Specification

YLH-6005 ships as a light yellow liquid in drums, with at least 12 months of shelf life unopened at ambient. No CAS number is published, so identification depends on the grade name and the lot COA.

Table 1. Product identification of YLH-6005 as published by the supplier.

Table 2. Published physical and cure properties of YLH-6005, with the basis behind each number.

One entry is derived, not measured: the 50 phr added weight is 100 × 95 ÷ 190, the stoichiometric ratio for the reference resin, so it tracks resin EEW.

2.2 Test Methods and Data Sources

Colour is a Gardner maximum measured at 25 °C per ASTM D1544, and viscosity a 25 °C figure. Resin epoxy content follows ASTM D1652; amine value on an incoming drum is normally determined by ISO 9702.

Gel time, thin-film set and Shore D build are shop tests, not cure kinetics. They rest on 100 g of mixed mass and a 15 g film at 3 mm, without a standard deviation or replicates.

3. Results and Discussion: How a Low Viscosity Epoxy Hardener Trades Speed for Strength

3.1 Equivalent Weight Sets the Ratio, Not the Rate

AHEW 95 g/eq fixes the stoichiometry: 50 phr against the EEW 190 reference resin, which makes the hardener 33% of the mixed weight.

Two grades share that ratio: YLH-6005 at AHEW 95 and YLH-6004 at 96 g/eq. Their gel times differ twofold, 23 min against 50 min, which equivalence cannot explain.

Amine value is not a shortcut to AHEW. Dividing 56100 by 270 returns 208 g/eq against a published 95 g/eq, so the two figures sit on different bases. Use AHEW for dosage and amine value as a lot fingerprint.

3.2 Comparison with Alternative Amine Hardeners

Five grades cover the band, all tested against the same EEW 190 resin, so Table 3 reads across.

Table 3. Published properties of five ambient-cure amine hardeners, tested against a liquid bisphenol A resin of EEW 190.

Read it by constraint, not rank. YLH-6005 leads on gel time and trails on colour at Gardner max. 3 against max. 1 for YLH-3023. YLH-6004 is slowest but strongest at 96.3 MPa.

YLH-3002 sits at 5000–12000 cps and needs 96 phr, nearly twice the mass per kilo of resin. That is a design for working life in thick sections.

3.3 Decision Matrix by Application Constraint

Four questions settle most enquiries.

Table 4. Selection matrix for ambient-cure amine hardeners, ordered by constraint.

Speed comes first: a missed recoat window costs a shift, while one Gardner point vanishes under a pigmented topcoat. If the coating is clear or light-tinted, the order reverses.

4. Formulation and Dosage Calculation

Dosage for a low viscosity epoxy hardener is one line of arithmetic: phr = 100 × AHEW ÷ EEW. At AHEW 95 that reduces to 9500 ÷ EEW, so the fraction falls as resin EEW rises.

Table 5. Hardener requirement for four resin EEW values at AHEW 95, with the split for a 20 kg kit.

Weigh to within 1% of the hardener figure. A 2% error shifts cure speed and hardness without ruining a floor. A 10% error leaves a tacky film that never hardens, however long you wait.

Blend arithmetic follows the same rule: 70 parts of EEW 190 resin with 30 parts of a 250 g/eq resin gives 205 g/eq, the last row above.

5. Processing Notes and Operating Window

• Weigh, do not volume-measure. At 1.02 g/cm3 against roughly 1.16 for the resin, using the 2:1 weight ratio by volume under-doses hardener by 12%.

• Mix 2 to 3 min at low shear. Air whipped in shows as pinholes in a self-levelling film and cannot be walked out.

• Treat 23 min as an upper bound: it was measured on 100 g, and a 1 kg batch holds its heat and gels sooner.

• Recoat between the 2.5 h set and the 10 h Shore D 70 point. If the film is past full cure, abrade before the next coat.

• Below 15 °C the reaction slows and the film may stay tacky overnight. Above 30 °C pot life roughly halves.

Figure 2. Applying a self-levelling epoxy floor coating; a 2.5 h thin-film set keeps the recoat window inside the same shift.

The mix thins sharply: 50 phr of a 350 cps hardener takes a 13000 mPa·s resin to about 3900 mPa·s on a logarithmic mixing rule. That is what makes a solvent-free self-levelling grade practical.

6. Applications

Two applications are published: epoxy flooring and electronic potting. They pull in opposite directions on cure speed.

Table 6. Published applications of YLH-6005, with the property that governs each one.

Flooring is the intended use; the blush-free claim is scoped to a topcoat on flooring, not every climate.

Figure 3. Potting a small electronic housing; gel time and exotherm, not hardness, set the size limit for a poured mass.

Potting is where fast gel bites. A 23 min gel on 100 g scales badly: a 2 kg pour in an insulating housing can exotherm enough to crack around inserts. Above that mass, YLH-6004 at 50 min is safer.

7. Limitations and Material Verification

7.1 Known Limits and Where YLH-6005 Is the Wrong Choice

Three published numbers argue against YLH-6005 in specific jobs. Gardner max. 3 rules out water-clear topcoats, 82.3 MPa bending is the lowest of the three grades publishing mechanical data, and a 23 min gel limits poured mass.

Two gaps matter more. No CAS number is published, so customs and any REACH screening need the COA. Amine value and AHEW also fail to reconcile, so verify both on the first drum.

It is also wrong where a specification asks for over 45 min of pot life at 25 °C solvent-free. Nothing published supports that.

7.2 Incoming Inspection, Packaging, Storage and Safety

A first-drum check covers Gardner colour by ASTM D1544, viscosity at 25 °C, amine value by ISO 9702 and water content by ASTM E203. Add a 100 g gel time if the line is rate-sensitive.

Packaging is a drum, net weight not published, and shelf life at least 12 months in unopened packing at ambient. Keep the cap closed: a modified amine picks up moisture and carbon dioxide, and the film degrades before the titration shows it.

Storage needs ventilation, no flame and no direct sunlight. The hardener is alkaline and irritant, so gloves and eye protection are the minimum and the MSDS governs handling and disposal. RoHS or REACH statements belong on the COA, not here.

8. Frequently Asked Questions

What mix ratio does YLH-6005 need with a standard liquid epoxy resin?

At AHEW 95 g/eq it is 50 phr on an EEW 190 resin, or 2.00:1 by weight. An EEW 184 resin needs 51.6 phr, an EEW 170 resin 55.9 phr.

Is YLH-6005 interchangeable with YLH-6004?

No. Both take 50 phr, yet gel times are 23 min and 50 min. Swapping changes the recoat schedule, and YLH-6004 gives more flexural strength at 96.3 MPa.

Does YLH-6005 eliminate amine blush?

The supplier states no blushing on top of epoxy flooring coatings. Blush is a reaction between amine, moisture and carbon dioxide, so cold damp weather can still produce it.

Can YLH-6005 be used for electronic potting?

Electronic potting is a published application, with Shore D 70 in 10 h on a 15 g film. Above a 1 kg pour, use a slower grade.

What is the CAS number of YLH-6005?

None is published. Request it on the COA or TDS before the first shipment; customs and safety documents usually need it.

Does YLH-6005 contain nonylphenol?

It is declared nonylphenol-free on the product page. That is a formulation statement, not a certification, so get it in writing on the TDS if a customer audits.

9. Conclusions

Among five ambient-cure amine hardeners, YLH-6005 is the fast option: 23 min gel and 2.5 h thin-film set against 30 to 50 min.

Stoichiometry is plain: 50 phr at EEW 190, 55.9 phr on a 170 g/eq resin. The cost is Gardner max. 3 and 82.3 MPa flexure.

Where speed governs, trial YLH-6005. Where colour or flexure governs, YLH-3023 at 30 min and YLH-6004 at 96.3 MPa answer better.

10. References

Yolatech product page for YLH-6005: https://www.yolatech.com/curing-agnet-ylh-6005 (accessed 2026-11-04).

Datasheet page for YLH-6004 at https://www.yolatech.com/curing-agnet-ylh-6004 (accessed 2026-11-04).

Datasheet page for YLH-3002 at https://www.yolatech.com/curing-agnet-ylh-3002 (accessed 2026-11-04).

Yolatech TDS, MSDS and COA for YLH-6005, carrying the lot CAS number; available on request.

ASTM D1544, Gardner colour of transparent liquids, the method behind the colour maximum.

ISO 9702, amine group nitrogen content of amine epoxide hardeners.

ASTM E203, water content by Karl Fischer titration.

ASTM D1652, epoxy content of epoxy resins (EEW).