Paint curing

Displacement of a volatile with a nonvolatile alcohol is an important reaction for curing paint films with amino cross-linkers and amino resias on textile fabrics or paper. FoUowiag is an example of a methoxymethyl group on an amino resia reacting with a hydroxyl group of a polymer chain. 

The reactions and some physical phenomena occurring in the curing paint film have been modelled with special attention being paid to the formation of carbon dioxide (chemistry) and the transport of the carbon dioxide from the paint layer (physics). 

The amino group concentration during curing Is assumed to be negligible. This will be checked in future experiments by measuring the amino content of the cured paint film. 

Measured airborne and blood concentrations of ethylbenzene in several occupational settings are presented in Tables 3 and 4, respectively. Most occupational exposures to ethylbenzene result from use of products containing technical grades of mixed xylenes. No ethylbenzene was found from off-gassing of cured paint in a hyperbaric pressure chamber under normal atmospheric pressure, but under higher pressures, levels of 0.4-4.5 ppm [1.7-19.5 mg/m ] were measured (Lillo et al., 1990). Silk screen operations were found to entail exposure levels of less than 4 mg/m (Verhoeff et al., 1988). Ethylbenzene may also be present in low-grade toluene preparations (Inoue et al, 1995). 

Figure 9 is a portion of the chromatogram of the extract from a cured paint film. The coating was extracted at 400 atmospheres (atm) at 125°C for twenty-minutes. The chromatographic conditions are described in Figure 9. The peak eluting at about twenty-five minutes corresponds to Tinuvin 440 (XIII) which was identified based upon retention time comparison to an authentic standard. Tinuvin 440 is a HALS and does not have a strong chromophore, but is easily detected using FID. The last peak appearing at thirty-four minutes is due to Tinuvin 900 (XIV), also identified by retention time comparison. Ve did not identify the peak at twenty-one minutes.

Electrocure. TM for a process for hardening or curing paint films on plastics by use of low-volt-age electron beams. Paints so treated cure in four sec or less at room temperature the finishes produced are said to be superior in resistance to abrasion and chemicals. The process can also be applied to other substrates such as wood, glass, metals, etc. 

Electron accelemtors are utilized in industrial processes such as crosslinking of polymers, curing rubbers, curing paints and adhesives, sterilization of medical devices and pasteurization of foodstuffs. 

Short oil alkyd resins can also be combined with nitrocellulose. They are readily soluble in typical nitrocellulose solvents (esters and ketones). Special short oil alkyd resins that are soluble in lower alcohols are often processed into furniture lacquers and acid-curing paints, and are also used in paper (spray) coatings and in flexoprint-... 

Combinations of bitumen with reaction-curing paint binders (e.g., epoxy resins and polyurethanes) are not usually employed in solvent-based paints due to their unsatisfactory compatibility. Only with high epoxy resin contents can a certain compatibility be achieved by addition of solubilizing phenols and aromatic oils. 

In other industrial application sectors there is an increasing tendency to employ low-solvent paints. In furniture production, for example, waterborne, UV-curing paints are superceding high-solvent nitrocellulose lacquers. 

Toluene [108-88-3] is mainly used in cellulose nitrate lacquers in heat-curing paints based on urea-, melamine-, or phenol - formaldehyde resins in alkyd resin paints and in paints based on chlorinated rubber, polystyrene, polyacrylates, or poly(vinyl acetate). Mixtures of toluene with esters are used to dissolve vinyl chloride copolymers and postchlorinated poly(vinyl chloride) [14.265]. 

The ISPC formulation stability was monitored by rheological measurements. Thermal analysis of cured paint films for the control paints and ISPC systems was conducted by differential scanning calorimetry (DSC) measurements. Electrochemical... 

The thermal properties obtained from DSC analysis of cured paint films, including the polyester control, ISPC polyester, alkyd control, ISPC alkyd, latex control, and ISPC latex baking enamels are listed in Table I. The Tg values are slightly... 

Table I. Thermal Chemical Data for the Cured Paint Films of ISPC and Control...

Uses Pigment for water- and solv.-based paints/coatings, UV-curing paints, powd. coatings, cosmetics, plastics Features Optically variable effect color reflection with copper-red-green color, deep gloss, high brilliance stable to 330 C Properties Colorless, yish. wh. powd. (platelets) dens. 1.3 g/cm bulk dens. 400 g/l surf, area = 1.0 nf/g pH = 7 (10% aq. susp.) conduct. 32 S (10% aq. susp.)... 

Features Good storage stability rapid touch-drying behavior good adhesion to steel and nonferrous metals good mech. props, of cured paint films good water resist. 

Uses Adhesion promoter for solv.-based air-drying and oven-cured paints Properties Colorless to yel. liq. vise. 250-300 stokes 75% solv. mixl. Use Level 1-3%... 

---