Waterborne HMDA Formulation Design:
By relying on the good ring-shaped shielding structure of hydrophobic cycloaliphatic amine HMDA, the hydrophilic structure on the main chain of the coating film is reduced, the hardness of the water-based coating film is improved, and the protection ability of the substrate is enhanced.
Basic parameters of water-based HMDA:
1. Aqueous HMDA self-emulsification: Particle size testing
It emulsifies easily, making application convenient.
Smaller particle size results in a denser paint film.
The emulsion has good stability and will not break down during the operation period.
2. Waterborne HMDA self-emulsification: curing performance
HMDA can give water-based curing agents good post-curing properties and build up hardness quickly. Both thin and thick coatings can meet the construction requirements of water-based flooring.
3. Water-based HMDA self-emulsifying: acid and alkali resistance
In a 10% H2SO4 test, the HMDA self-emulsifying paint film turned white within 1 day, and the bubbling phenomenon was not obvious.
In a 10% HCl test, the HMDA self-emulsifying paint film turned white within 2 days, and the bubbling phenomenon was not obvious.
In a 20% NaOH test, no obvious corrosion was observed in the HMDA self-emulsifying paint film within 7 days.
Water-based HMDA self-emulsifying curing agent has significantly improved acid and alkali resistance compared to commercially available products.
4. Water-based HMDA self-emulsifying: Topcoat
The introduction of hydrophobic amine HMDA not only improves the basic parameters and resistance, but also gives the coating film a higher gloss.
5. Water-based HMDA anti-corrosion and curing agent:
Waterborne HMDA anti-corrosion curing agent is a waterborne epoxy resin curing agent based on the alicyclic amine HMDA system, which is used in the base, intermediate and top coatings of waterborne epoxy anti-corrosion coatings.
Water-based HMDA anti-corrosion curing agent has excellent resistance to salt spray corrosion, long service life, fast drying speed, and good comprehensive properties such as hardness, impact and flexibility after coating curing. It also has excellent adhesion to metal and concrete surfaces.
Early water resistance test
Film thickness: 30~50μm; Test method: HG/T 5176-2017
The water-based HMDA coating film showed no obvious blistering, corrosion, or other phenomena, and the coating film remained unchanged.
The paint film of product #1 sold in the market showed signs of rust.
No obvious corrosion was observed in the paint films of commercially available products 2 and 3.
Film thickness: 30~50μm; soaking in 5% NaOH solution for 24h.
The water-based HMDA coating film was soaked in 5% NaOH for 24 hours and no obvious corrosion was observed. The coating film showed no change and the gloss was not reduced.
The paint film of commercially available product 1 showed obvious blistering and numerous bubbles.
The paint film of commercially available product 2 also showed obvious bulging, but less bubbling.
No obvious corrosion was observed in the paint film of commercially available product No. 3.
Salt spray resistance test
Film thickness: 30~50μm; neutral salt spray, 480h sample
No blistering, rust spots or other corrosion phenomena were observed on the water-based HMDA paint film sample, and the corrosion widening at the scratches was not obvious.
The commercially available paint film sample showed obvious rust at the scratches, with some rust widths exceeding 1mm, and the paint film also exhibited slight blistering.
The rust at the scratches on the two commercially available paint film samples was not obvious, but the paint film showed severe blistering.
The commercially available sample of paint film showed obvious rust at the scratched areas and obvious blistering of the paint film.
