Acrylic thickeners

The commercial success of acrylic thickeners in pigment printing is attributable to the... 

A major drawback of synthetic thickeners when used with dyes is their sensitivity to electrolytes. Most soluble dyes behave as highly ionised electrolytes and disperse dyes contain anionic polyelectrolyte dispersing agents unless they have been formulated with nonionic systems specifically for use with acrylic thickeners. Consequently there is a loss of viscosity this can be quite pronounced although it depends on circumstances, particularly on the dye concentration. As already mentioned, this can be alleviated to some extent by copolymerisation with acrylamide during manufacture. Otherwise it is necessary to try to eliminate all electrolytes from the system or to increase the concentration of thickener. Such measures have their limitations in practice, however. Alternative synthetic thickening... 

A versatile group of highly effective acrylic thickening agents for use in aqueous adhesives and latex coatings. Suitable for use with many latex types including natural rubber, S.B.R., PV acetate, PVC, Polychloroprene, acrylic and nitrile. 

Chem. Descrip. Fatty acid modified polyester Uses Emulsifier, stabilizer for pigments and colorants in decorative paints activator for bentonites and associative/acrylic thickeners Features Max. color development of the cotorant higher pigment loading optimum color acceptance of the colorants in the ba paints Properties Dark brn. liq. dens. 0.95-1.05 g/cm (20 C) add no. 20-30 amine no. 30-40 100% act. 

Synonyms POE (10) oleyl amine Definition PEG amine of oleic acid Uses Surfactant for textile auxs. emulsifier, anti-irritant in shampoos neutralizer for acrylate thickeners antistat, foaming agent, and mild detergent in cosmetics Trade Name Synonyms Monopol OM-1020 [Dongnam Chem. Ind. Ltd http //www.dongnamchem.com], Protox 0-10 [Protameen http //www.protameen.com] Serdox NRA 10 [Sasol Servo BV http //www.sasolservo.com]... 

The structures of the different types of alkylamines are shown in Figure 14.21. These amines, which are used extensively in the cosmetic industry (typically as their salts with phosphoric, citric or acetic acid), exhibit surface activity, water solubility and compatibility with a variety of other surfactants. They can also serve as neutralizing agents for resins and acrylate thickeners. 

The presence of salts in formulations containing anionic poly(acrylate) thickeners can... 

Figure 30 Schematic representation of swollen, cross-linked, hydrophobically modified, cationic acrylate thickener stabilizing an emulsified oil droplet. 

It is not unreasonable to expect that aqueous polymer dispersions will be effective in gels and mousses. Furthermore, the technology of hydrophobically modified acrylate thickeners discussed in Section II.A.3.a, useful for suspending latex particles, fits naturally into fixative gels. 

Multiple-Particle Tracking (MPT) Measurements of Heterogeneities in Acrylic Thickener Solutions... 

Keywords Acrylic thickeners Microheterogeneity Microrheology Multiple-particle tracking... 

Heterogeneities in Acrylic Thickener Solutions 74 Pettersson T, Feldoto Z, Claesson PM, Dedinaite A The Effect of Salt Concentration and Cation Valency on Interactions Between Mucin-Coated Hydrophobic Surfaces 1... 

The commercial attractiveness of synthetic acrylic polymers is enhanced due to the fact that a given chemistry or composition is often available in several different physical forms. Much of the manufacturing process technology involved in the production of acrylic thickeners has close similarity with the methods used in the production of flocculants. This is also covered in Chapter 6. Specific aspects of the manufacturing process for each physical form will be considered here in the context of the use of such polymers as thickening agents. 

Finally, the structure or network of polymer chains combined with micellar clusters occurring in solution from such associative polymers also results in a modified rheological profile with respect to the viscosity versus shear rate behaviour compared with the previously known Hnear and cross-linked types. This was of particular interest in formulations such as water-based paints and will be covered in more detail in a later section on rheological profiles of acrylic thickeners. 

Waterphase thickeners thicken the aqueous phase of the system due to dissolved polymer. Cellulose derivatives are most commonly used, but starch derivatives and acrylic thickeners are other groups in this class. The advantage of these thickeners is that they operate independently of the system, and hence rheological behavior of the paint is comparatively predictable. 

Associative thickeners increase the viscosity of the paint by interacting with other paint ingredients through bridging of particles (surface to surface) or interaction of adsorbed layers. The interactions are assumed to be through hydrophobic forces. The operative mechanism is illustrated in Figure 5.9. Important groups in this class are associative acrylic thickeners, associative cellulose ethers and hydrophobically modified ethoxylated urethanes (HEUR). 

Acrylic thickeners, also known as alkali-swellable emulsions, are used to a limited extent in cheap interior wall paints. They are acids containing acrylic copolymers supplied in liquid form as an emulsion. The main limitation of these thickeners is that the thickening action is a function of the pH of the paint system and therefore the viscosity varies with pH of the system. 

Associative acrylic thickeners are also known as hydrophobically modified alkali-swellable emulsions (EASE). Chemically, they are copolymers composed of three blocks ... 

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