Binders synthetic

Almost all synthetic binders are prepared by an emulsion polymerization process and are suppHed as latexes which consist of 48—52 wt % polymer dispersed in water (101). The largest-volume binder is styrene—butadiene copolymer [9003-55-8] (SBR) latex. Most SBRlatexes are carboxylated, ie, they contain copolymerized acidic monomers. Other latex binders are based on poly(vinyl acetate) [9003-20-7] and on polymers of acrylate esters. Poly(vinyl alcohol) is a water-soluble, synthetic biader which is prepared by the hydrolysis of poly(viayl acetate) (see Latex technology Vinyl polymers). 

Synthetic Binders in Paper Coatings Technical Association of the Pulp and Paper Industry, 1975. 

In a first classification, we can distinguish (i) boards made with an external synthetic binder, such as urea-formaldehyde or phenol-formaldehyde resins for thermosets, and (ii) boards with internal natural binders. The products cited below do not constitute an exhaustive list. 

In this case, water is sprayed on sawdust instead of a synthetic binder. Hot-pressing of the mat is carried out to partially hydrolyse some macromolecules contained in the wood as well as thermal degradation of free sugars and other small molecules. The degradation products contribute to the cohesion of the particles. 

Starch is a major binder for paper coatings. It is used as a sole binder or combined with various synthetic binders. Blends with aqueous dispersions of poly(vinyl alcohol),... 

Consolidation of the damaged material by replacing or reinforcing the affected matrix with a synthetic binder... 

The principal oxygenated solvents are ketones, esters, glycol esters, and alcohols. They offer much stronger solvency and are widely used as active solvents for synthetic binders. Ketones are characterized by their strong odor, range of water solubility, and evaporation rate. Esters provide solvency nearly equal to ketones but with more pleasing odors. 

To explore whether incorporation of native DNA structural elements such as the sugar-phosphate backbone into synthetic binders could be employed to dictate the formation of defined complexes such as helicates, the dinucleoside mimic (81) has been synthesised. In (81), the nucleic base has been replaced by the metal-binding ligand 2,2 -bipyridine, linked to the sugar by a methylene bridge... 

Most synthetic binders are softer and more flexible thant hard resins. Consequently, they impart good elasticity, impact resistance, and improved adhesion, even to critical undercoats, as well as offering adequate resistance to weathering and chemicals. These binders are produced with a property profile tailored to suit particular application methods and to comply with a range of technical requirements, including environmental protection, low toxicity, and suitability for recycling and disposal. 

Phenolic resins (i.e., condensation products of phenols and formaldehyde) are among the oldest synthetic binders, and their first use in paint technology dates back to the early 1920s. Their primary uses have constantly changed since then, and new classes of synthetic binders have become increasingly important. 

Powder coatings have been widely accepted in the industrial coating market because they are completely solvent free and show excellent mechanical and physical properties (13). Usually they contain a synthetic binder, a reactive cross-linker, pigments, and several additives to improve flow and other film eharacteristics. Various application techniques have been developed in reeent years. Powder coatings are normally sprayed electrostatically on grounded substrates and are heat-cured thereafter. Because these systems do not contain organic solvents, no emission of organic solvents takes place. However, the need for an oven to melt the resin and start the chemical reactions makes this environmentally friendly process unsuitable for do-it-yourself markets. 

CappiteUi, R, T. Learner, and A. Cummings, Thermally assisted hydrolysis and methylation-gas chromatography/mass spectrometry for the chemical characterization of traditional and synthetic binders, in ICOM Committee for Conservation, 13th Triennial Meeting, Rio de Janeiro, September 22-27, 2002, pp. 231-237. 

Over the last few years, the industry has developed synthetic binders that can be coloured in any colour with relatively less cost. Synthetic bitumens have almost the same properties as common paving bitumens. More information can be found in Shell Bitumen (2003) and the Web. 

Figure 6.18 Monomer formulas of some synthetic binders.

A coating consists of binder (polymer resin), solvent, pigments and filler. Polyurethane resins have a special place among the natural and synthetic binders in the coating industry due to their excellent adhesion to various substrates. Polyurethane paints and varnishes can be classified in several groups ... 

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