Polyacrylate dispersions

Figure 7 Hercules viscosities for AMP and polyacrylate dispersed kaolin...

Colloid Chemistry of Sodium Polyacrylate Dispersed Calcium Carbonate Slurries... 

A series of slurries of high solids, dispersed ground calcium carbonate were prepared. Firstly, a sample of Carrara marble was ground without dispersant to a mean size of 0.5 fim. This was then filtered to a solids level of 76% (volume fraction 46%), before being thoroughly mixed with the required dose of sodium polyacrylate dispersant and adjusted to a constant solids level of 70%. Doses ranged from zero to 25mgg (2.5%) of calcium carbonate. Samples were then left for two days to reach a steady-state adsorption level. After this they were sheared and their viscosity (Brookfield RV, 100 rpm, spindle 3) was measured. 

From the preceding discussion, the most obvious way to improve the performance of polyacrylate-dispersed calcium carbonate slurries is to reduce the solution ionic strength by reducing the amount of non-adsorbed polymer in solution. 

Figure 13 Effect of pH on viscosity of polyacrylate dispersed kaolin 0.6 pm, 70% solids)...

NOTE However, there exist many cooling system operators and (unfortunately) small water treatment service companies who fail to understand that simple polyacrylate dispersants are generally unsatisfactory for use in stabilizing phosphate. 

The technique is very versatile and adaptable. Plastisols may be applied overall or—by means of engraved screens—can be printed in selected areas, in weights that can be varied between 30 g m-2 and more than 500 g m-2. Suitable substrates include paper, other non-woven materials, glass-fibre webs, and textiles. Water-based inks can be employed as coatings or in printed designs. For relief effects, expandable aqueous polyacrylate dispersions offer an alternative to expandable plastisol inks. They are dried and then expanded at 120°C, a temperature much lower than is required for vinyls with a multi-station machine, a wide variety of products can be made. 

PERAPRET D and PERAPRET DS are anionic polyacrylate dispersions with low viscosity. They have a solids content of approx. 25% and a pH of 2-3. They are both used to facilitate the removal of soil from textiles, particularly blends of cellulosic and synthetic fibres, under normal conditions of household washing. They are, therefore, applied as additives in soil-release finishing. The treating liquor must, of course, only contain products that do not impair this desired effect. 

In combination with polyacrylate dispersions, e.g. PERAPRET HVN, PERAPRET F and HELIZARIW BIMDER FA, finishes with LURAPRET B25 can be fixed wash-fast. The product is not compatible with some water-repellent and softening agents. 

Methacrylic acid-ethyl acrylate capalymer (1 l)l°> Methacrylic acid-ethyl acrylate copalymer (1 1) dispersian 30%" > Methacrylic acid-methyl methacrylate capalymer (1 1)W Methacrylic acid-methyl methacrylate copolymer (1 Basic bulylated methacrylate copolymer Polyacrylate dispersion 30% ... 

Albano, M.P. and Garrido, L.B., Rheological properties of 813X4, pseudoboelimite and bayerite coated 813X4 suspensions with ammonium polyacrylate dispersant. Colloids Surf. A, 203, 117, 2002. 

Nonpolar polymers such as polyethylene, polytetrafluoroethylene, and polystyrene are especially significant because of their low loss values over the widest frequency range. For polar polymers such as poly(vinyl chloride)s, poly(vinyl acetate)s and polyacrylates dispersion is observed at lower frequencies than for the monomers, as expected. Two or more dispersion regions are commonly observed. They... 

Aqueous two-pack polyurethane paints are obtained by combining, for example, hydroxyl-containing polyacrylate dispersions with water-emulsifiable, low-reactive aliphatic polyisocyanates. 

Sodium polyacrylate dispersant, oil recovery Pentasodium ethylene diamine tetramethylene phosphonate... 

So, it was only a small surprise when we found a 10 times higher conductivity (between 20 and 100 S/cm) at 40% organic metal content in a thermoplastic polyacrylic dispersion. Furthermore, for the first 70 K temperature decrease, conductivity increased, as is the case for conventional metals (Figure... 

Polyvinyl acetate ester or polyacrylate dispersions Salts and low molecular emulsifiers are dialysed In the dialysate, salts and emulsifiers, in the dialysate residue, protective colloid polymerisate... 

The piimaiy particles within a suspension containing 40 wt% of AI2O3 fine particles and a polyvinyl alcohol binder Mowiol 4-88 were dispersed using an electrosteric sodium polyacrylate dispersant with a chain length of 8000 g/mol NaPA 8000. The dispersant addition leads to a slight reduction of the viscosity of the suspension. The pH value is slightly increased at constant suspension density. As already described in literature [26], the additirm of the dispersant results in an increased dynamic mobility of the primary particles. The sedimentation speed is reduced. 

Solids - Sodium Silicate dispersed 71.5% Solids - Sodium Polyacrylate dispersed... 

Because the monomers used are water soluble, polyacrylate dispersing agents are manufactured by redox polymerisation directly in water. 

HASE thickeners are polyacrylate dispersions that contain a higher amoimt of carboxyUc acids, predominantly acryUc acid or methacryUc acid. Upon neutralisation during the paint manufacturing they sweU and thicken the paint. Due to additional hydrophobic functional groups attached to the polymer backbone, they can interact with the hydrophobic part of surfactants and the hydrophobic entities of other thickener molecules forming a kind of micellar strucmre in the water phase. In addition, they can interact with hydro-phobic domains on the surface of emulsion polymer binders. This extensive hydrophobic interactions improve efficiency of the HASE thickener and helps the coating formulation... 

A Tenlo 70 Tergitol XD Tergitol XH Tergitol XJ Teric N2 Teric N4 Teric N5 Teric N6 Teric N9 Teric N10 Teric N15 Ultradispers AB 30 Ultradispers MD 21 Ultradispers MP 10 dispersant, latex paints/coatings Daxad 32 Potassium polyacrylate dispersant, latex stabilization Synperonio A20 dispersant, latexes... 

The most important adhesive raw material compositions for adhesive labels are polyacrylate dispersions, styrene-butadiene rabber solutions, and styrene-butadiene-styrene (SBS) and styrene-isoprene-styrene (SIS) hot-melt adhesives. Permanent and removable UV-cross-linkable acrylic hot-melt adhesives have recently also been introduced [19-22]. 

Adhesion and cohesion of polyacrylate dispersions can be varied over a broad range and matched to many appHcations through the type and combination of low Tg ( soft ) and high Tg ( hard ) monomers, the choice of auxiharies, and the control of the molecular weight and process parameters [26-29]. Some examples are given below. The influence of glass transition temperature (Tg) of acrylic homopolymers on tack (according to A. Zosel [30, 31]) at various temperatures is shown in Fig. 8-2. 

The polyacrylate dispersions optimized in this way for pressure sensitive adhesives are produced and supplied with solids contents between 50 % and 70 %. Average particle sizes are typically between 100 run and 1000 run. However, dispersions with a high solids content (> 60 %) and low viscosity (<500 mPa s) need to have a bimodal or multimodal particle size distributions. The viscosities of most commercial products are generally between 10 and 1000 mPa s but high-viscosity dispersions... 

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