Binders and Solvents

All paints consist of a binder (sometimes called a medium) and pigment. Materials consisting of binder only are called varnishes. Most paints and varnishes contain solvent in order to make the binder sufficiently liquid to be applied. The combination of binder and solvent is called the vehicle. Some paints are available without solvent (e.g. solventless epoxies) but these generally require special methods of application (e.g. application of heat) to reduce the viscosity. 

Although formulation is an art, science finds its place in the characterisation of the raw materials, in the design and testing of the series of experimental formulae and in the interpretation of the results. In addition to possessing an intimate knowledge of pigments, binders and solvents, the paint formulator must also be well acquainted with raw material costs and availability, paint making machinery, and the market s performance requirements. 

For the purpose of paint formulation the most important units of equipment are the laboratory ball mill, bead mills and high speed dispersers. The most common, the ball mill, consists of a cylindrical porcelain vessel a little more than half filled with steel, porcelain balls or pebbles. Pigment, together with sufficient binder and solvent to make a free-flowing mix, is loaded into the mill until it is approximately two-thirds full. The mill is then closed and fixed into a device whereby it is made to rotate about its major axis. Normally, a period of about 16 hours is required for thorough dispersion of the pigment, whereupon the mill-base is emptied out and blended with the remainder of the ingredients. 

Results of the PMV on VOC/SVOC analysis from different newspapers according to RAL-UZ 14 annex 4 show that worldwide different ink binders and solvents are used. This is documented in Table 3 by the amount and composition of the purgeable volatile substances from the newspapers. Especially in Asia, increased amounts of... 

A red star might be based on potassium perchlorate, strontium carbonate and charcoal together with various binders and solvents to facilitate the pumping of solid stars. The composition for a green star... 

A highly concentrated dispersion of carbon black is first prepared with a portion of the binder and solvent. The viscosity of this concentrate is a function of the particle size, structure, and surface chemistry of the black, the type of binder and its interaction with the pigment black, and the proportions of black, binder, and solvent. The final paint is made from the concentrate by adding more binder and solvent, its carbon black concentration is 3-8% referred to the solids content. Wetting agents are sometimes added to improve dispersibility and prevent flocculation. A number of concentrates for paint manufacture e.g., carbon black-nitrocellulose chips or carbon black -alkyd resin pastes, can be obtained from paint producers. 

The principal components in a paint are pigment, binder, and solvent. The basic steps in the manufacture of paints are [780] ... 

Migration should not occur when organic pigments are used in paints that are applied in differently colored layers on top of each other. Resistance to migration depends on the pigment, binder, and solvent. 

Pigments can also influence other coating properties (e.g., film gloss) as a result of complex interactions between the pigment, binder, and solvent, and the method of application. 

The pigment is dispersed in the binder and solvent which wet and stabilize the pigment. Destabilization of the pigment (e.g., reagglomeration, flocculation, and flotation) must not occur when the other paint components are added. 

Features High mol. wt. polymeric wide compat. range from NC-systems to long oil alkyd systems strong resist, to binder and solvent shock long-term deflocculation stability high color str. 

Oily agents as preventive treatment against fungi and insects pigment-free preparations containing binders and solvents organic fungicides and insecticides... 

Interactions between binders and solvents in paints and varnishes are very important. - With the aid of solubility parameters solvents or mixtiues of solvents which produce... 

Paints or lacquers are composites of, in general, three components pigments, binders, and solvents. Depending on application, the nature of the pigment can vary between extremely wide limits (see also Chapter 34). The binders are also known as film formers they are exclusively polymers or prepolymers, that is, thermoplasts, thermosets, elastomers, and elastoplasts. The nature of the solvent can also vary within wide limits according to the type of film former and the desired application. Here, solvents are described as good in the paints industry when they lead to low-viscosity paints or lacquers. Such good solvents are usually poor solvents in the thermodynamic sense (see also Chapters 4 and 6). 

The pigments and binder contents, together, are usually given as the solids content. Conversely, the sum of the binder and solvents content is known as the vehicle. Paints without pigment are known as varnishes. 

Table 8.11 Examples of binders and solvents used in industrial coatings ...

---