Water-borne emulsion polymers

Water-borne emulsion polymers are used in formulating automotive coatings for electrocoat, primers and basecoats. Clearcoat polymers are primarily still solvent-borne. A powder dispersed in water (powder slurry) has been developed as a binder for clearcoats [7]. 

Polymer latices are of extreme technological importance in the development of water-borne paint systems. One method for the production of these latices involves emulsion polymerization, which allows careful control of... 

Emulsion polymerization usually leads to high MM products and in many cases to MMDs somewhat narrower than found in polymers produced in homogoieous free-radical polymerizatioa The mechanisms of particle nucleation and radical aitry operative in emulsion polymerization, however, also lead to the formation of short water-borne oligomers (c. 2-20 monomo- units d Jending on the polarity of the monomer). The characterization of these tdigomeric species is of considerable importance from a mechanistic point of view [162-168]. 

Since the 1970s polymer dispersions manufactured by emulsion polymerization have increasingly substituted solvent-borne paints, coatings, adhesives and inks. Water-based emulsion systems have made a significant contribution to VOC-reduction in corresponding industries. The emulsifier in... 

Uses Used in mfg. of water-based coatings and adhesives as crosslinker in water-borne polymers, esp. polymers contg. reactive h roxyl groups offers controlled reactivity and extends pot life in latex emulsions Features Provides improved solv. and water resist. prods, will yel. on exposure to UV light... 

Until the mid-1950 s, vinyl acetate was a moderate volume product used to produce specialty polyolefins, such as cling films. However, in the 1950 s, emulsion polymerization ("latex") began to emerge as a major new product line in the chemical industry. (Emulsion polymerization uses surfactants to generate water based emulsions of polyolefin polymers. These products are most familiar to the consumer as water borne paints, but are also found in a wide variety of... 

For completeness we note that two other FFF subtechniques can be applied to certain polymeric materials, although applications are so far limited. Sedimentation FFF is the most notable example. For this system the driving force (centrifugally induced sedimentation) is directly proportional to molecular mass in a form that is calculable from first principles (see eqn 8.7). Accordingly, molecular mass distributions can in theory be obtained by calculation without empirical calibration. This principle has been successfully applied to the determination of the molecular mass and particle size distribution of numerous colloidal particles including viruses, latices, emulsions, liposomes, protein aggregates, and water-borne colloids [5,7,9]. However, as noted earlier, sedimentation FFF is not applicable to many polymers of interest because sedimentation forces (even in a powerful centrifuge) are not adequate to drive the components to the accumulation wall of the FFF channel. Thus molecular masses of less than 10 cannot be well... 

A further means of achieving efficient light scattering in a liquid crystal device is to disperse a nematic material in a plastic matrix [63, 64]. The plastic is chosen so as to have a refractive index which is equal to no of the liquid crystal. One fabrication route [63] involves forming an emulsion of liquid crystal in a water-borne polymer system, which is then coated onto a substrate and dried. The product is a plastic film containing many small, separate droplets of liquid crystal. Alternatively, the liquid crystal may be dissolved in a reactive monomer [65], which is polymerized in a thin layer. As the polymer forms, the liquid crystal is expelled from solution and forms a similar array of droplets. Another route uses a polymer in... 

The first acrylic emulsion polymer was already introduced in 1931 by the German I.G. Farben Industrie for leather finishing. But the large-volume applications occurred not imtil the 1960s when new water-borne adhesives and paints were introduced. 

When printing corona-treated polymer films with water-borne inks, it is typical to achieve durable film-ink adhesion. The same is true for water-based flexographic coatings. Both these inks and coatings can, individually, demonstrate the water resistance properties provided by the resin emulsion additives. If the polymer substrate has a high percentage of surface area covered by the ink, it would be bene-... 

Anionic coatings systems for water-borne topcoats are emulsion polymers, miniemulsion polymers, polyurethane dispersions, different types of dispersions of acrylic resins in water and amino resins, water-borne polyesters, polyurethanes. Many of the polymers are hydroxyl containing and cured with various melamines and blocked isocyanates. The polymers are mainly stabilized in the water phase by neutralization of anionic groups with volatile amines (2-amino-2-methyl-l-propanol). Cross-linkers like aminoplast resins, alkoxy silanes, blocked epoxy resins, carbodi-imides can be used. 

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