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Polyurethane, silicone-urethane, polyurethane-acrylic and silicone-urethane-acrylic aqueous dispersions– DPU-PJ

DPU-PJ aqueous dispersions were developed for application as paint and lacquer binders, applied on wood, metals or plastics and also to be directly applied as coating materials (of wide hardness range) or as additives to coating materials based on other aqueous dispersions, e.g. acrylic dispersions.

DPU-PJ dispersions can form coatings cured by UV irradiation or oxygen from air (with a siccative). Choosing suitable composition enables to produce DPU-PJ dispersions with various raw material cost, forming coatings with wide range of hardness, elasticity and adhesion. Based on the developed dispersions, two-component compositions (dispersion + hardener) can be obtained.

DPU-PJ dispersions have the form of opalescent liquids of low viscosity, pH about 8 and solids content about 33 %.


A brief description of the technology

At the first stage the starting polyol (or polyol mixture) is dehydrated under reduced pressure, and then, at increased temperature and in inert gas atmosphere, a polyaddition of polyol, dihydroxy carboxylic acid and cycloaliphatic diisocyanate is carried out in the presence of small (several percent) amounts of a diluent –
N-methylpyrrolidone (NMP). Resulting NCO-terminated prepolymer containing carboxyl groups is neutralized with a tertiary amine, obtaining a concentrated prepolymer-ionomer solution in NMP. At the second stage the concentrated prepolymer-ionomer solution is dispersed in water and then the polymer chain is extended with polyamine.


Advantages of the technology offered

The technology allows to obtain dispersions forming coatings of wide range of properties.


Equipment

  • typical reactor with an anchor stirrer and a heating / cooling jacket, capable to keep inert gas atmosphere and perform the process under reduced pressure,
  • high speed mixer with a heating / cooling jacket,
  • tanks to store reactants.

Laboratory equipment:

  • equipment to determine the hydroxyl value and NCO groups contents,
  • viscometer or rheometer,
  • pHmeter,
  • equipment for testing coating properties.


Patents

The technology was not patented.


Market competitiveness

There are polyurethane and polyurethane-acrylic dispersions available on the market, special grades forming coatings cured by UV irradiation or by oxygen from air (with a siccative). However, neither silicone-urethane nor silicone-urethane-acrylic dispersions are commercially available.


Information

Dr. Janusz Kozakiewicz, D.Sc., Chem. Eng., prof. of ICRI

phone: + 48 22 568 23 78


Jarosław Przybylski, M.Sc., Chem. Eng.

phone: + 48 22 568 26 46, + 48 22 568 26 47