Cellulose thickeners are chemical compounds derived from Cellulose ether families that are able to absorb water highly. In addition to increasing viscosity, they offer different properties e.g. stability, water retention, open-time, color development, etc.
The pros of these thickeners are compatibility with different formulations and also different range of pH, but one of the cons of them is poor levelling effect. Further, these thickeners are not resistant to microorganism’s attack. Hence, suggested to use in – can preservatives to prevent contamination.
Types of cellulose thickeners:
- Hydroxyethyl cellulose (HEC)
- Methyl Hydroxy ethyl cellulose (MHEC)
- Hydroxy propyl methyl cellulose (HPMC)
- Ethyl Hydroxy ethyl cellulose (EHEC)
- Carboxymethyl Cellulose (CMC)
Hydroxyethyl cellulose (HEC): This thickener is applied for various industries including paints and coatings, adhesives, resins, cosmetics, detergents, etc. In paint and resin industry, Hydroxyethyl cellulose offers better feature comparing other Cellulose ether derivatives. The characteristics are as follows:
- Minimum effect on resin and paint gloss
- Pigment compatibility
- Better water retention
- Spatter resistance
Polyacrylate thickeners are acrylic copolymer emulsions. they are based on ASE (Alkali Swellable emulsions) and HASE (Hydrophobically Modified Alkali Swellable emulsions). these rheology modifiers can increase viscosity. Thanks to their liquid delivery form it is easy to incorporate. furthermore, due to their chemical structure they will not face microorganism attacks. By increasing pH to alkali range, they would absorb water and swell, and this process causes thickening effect.
Difference between ASE and Associative acrylate thickeners (HASE) -which are also known as Hydrophobically Modified Alkali Swellable Emulsions, is that HASE contain hydrophobic groups that result more thickening efficiency, and improve scrub resistance.
Polyurethane thickeners (HEUR)
Polyurethane thickeners or Hydrophobically modified Ethylene oxide – based Urethane, are one of the innovative products among water – based thickeners. They can offer various features and provide good characteristic such as, levelling, scrub resistance, etc. moreover they perform in different range of pH and also will not face microorganism attack.