Alkyd enamel

Parlon has been used in pyrotechnic tracer formulations as a color intensifier and binder (Ref 4). It is also employed as a base for rapid drying concrete paints and alkyd enamels (Ref 5) Refs 1) G.F. Bloomfield, JChemSoc 1943, 289 2) Parlon, Properties and Uses , Hercules... 

In the laboratory, alkyd paints are preferable due to their durability and cleanability. Although latex paints have come a long way since their development, they do not measure up to the alkyd variety in laboratory applications. The popular latex enamels, in particular, are inferior to a good alkyd enamel. They are hard to apply smoothly and they pick up dirt far too fast. 

Paints made for high chemical resistance are also available. One type is similar to regular alkyd enamel but has been modified for greater resistance. It has proved excellent for many laboratory applications w here regular paints w ould not stand up, but even this type has its limitations. 

Rusting and blistering of an alkyd enamel coating on metal substrates. Salt fog resistance (300 h)... 

An additional complexity for alkyd enamel paints is mid-term emissions. Table 16.5 shows the emissions from a typical full-gloss alkyd enamel paint (Brown, 2000). Note the very high early emissions of the solvents (especially c.f. the... 

Table 16.5 VOC emissions from a solvent-based paint alkyd enamel full-gloss (23°C, 50% RH, 1.0h 0.5m m4).

Brown (2000) evaluated VOC emissions from two of these products, as summarized in Table 16.6. Paint 1 was claimed to use orange peel oil as its base. It exhibited very high and fast-decaying emissions of C7-C10 alkane and limonene, with EF at 2 hours of 70000 and 120000 tgrn 2 h 1, respectively. Paint 2 was claimed to be based on vegetable oils and was virtually nonemitting at application, but emitted several malodorous aldehydes (including formaldehyde) and little else from 8 hours after application. This was considered to show an auto-oxidation reaction occurred for this product, similar to that observed with the alkyd enamel paint discussed earlier. 

Embrittlement. This can occur where the curing process continues throughout the life of the coating—for instance, alkyd enamel drying by oxidative cross-linking. 

Butanol is used in the production of methyl ethyl ketone and ec-butyl acetate, as a solvent in lacquers and alkyd enamels, in hydraulic brake fluids, in cleaning compounds, and its xanthate derivatives in ore flotation. 

In cathodic delamination, the delamination rate of an organic coating under a cathodic potential depends upon the applied potential, electrolyte solution, and metal substrate (22,25). Cathodic delamination tests were conducted for all three commercial paints. As an example, Figure 5 shows the cathodic delamination plots of control alkyd enamel and water-reducible ISPC coated on bare CRS coupons. Curves Sa and 5b represent delamination area for the control alkyd enamel and the water-reducible ISPC formulation, respectively curves 5c and 5d are the respective plots of delamination current for the two formulations. The delamination test was conducted in a 3% NaCI solution the alkyd coated CRS coupon served as a cathode and was polarized at -I.IV versus a saturated calomel electrode. A significantly slower delamination rate was obtained for the ISPC formula (curve 5b) as compared to the control alkyd enamel (curve 5a). At 44 hours of delamination time, the entire painted area of the working electrode (almost 20 cm x 20 cm) for the control alkyd paint had been delaminated, whereas the delamination area of the water-reducible ISPC was only as little as 1 cm indicating a remarkable coating adhesion improvement for the alkyd ISPC painted on bare CRS coupon. 

Uses Esteritication/transesteritication catalyst for mfg. of plasticizers and sat. or unsat. polyesters, po d. coatings, coil coatings, air-drying water-reducible alkyd enamels... 

Uses Pigment in paints, emulsion paints, printing inks, linoleum, textile printing, rubber, plastics, alkyd enamels, lacquers, paper Manuf./Distrib. EC Pigments USA Zhuhai Skyhigh Chems. 

The variability in the pyrolysis profiles of the different classes of coatings is self-evident. The interpretation of the composition revealed is as follows The acrylic lacquer (General Motors) is a methyl methacrylate/methacrylic acid copolymer plasticized with dibutyl-, butyl cyclohexyl-, and butyl benzyl phthalates. The acrylic enamel (Ford) is a styrene/ethylhexyl acrylale/methyl methacrylate terpolymer. The alkyd enamel (Honda) pyrolysis profile indicates that the paint resin is an orthoph-thaUc alkyd containing a butylated-amino resin cross-linking component. 

Alkyd enamels occurring as original baked enamels or spraying enamels may be identified by the THM pyrolysis derivatization modification of the Py-GC technique. These alkyd polyesters are converted to methyl derivatives of their polyol,... 

FIGURE 8.3 THM chromatogram of the baked alkyd enamel paint smear. i-BuOH = isobutanol, BuOH = butanol, MB = methyl benzoate, P3ME = pentaerythritol trimethyl ether, DMOP = dimethyl orthophthalate, M = triazines from melamine, C,2, C,4, C,g, and C j = respective fatty acid methyl esters. 

From the THM chromatogram it is evident that the paint is a pentaerythritol-orthophthaUc acid baked alkyd enamel having a coconut nondrying oil cross-linked with a butylated melamine formaldehyde resin. 

Break-in tools used to gain access to premises may well carry traces of paint that have abraded from painted surfaces at the point of entry. Commonly encountered household paint types include polyvinyl acetate (PVA), acrylics, alkyd enamels, epoxies, and chlorinated rubbers. Py-GC can distinguish between these different classes (Figure 8.4). 

Furthermore, their polymer class and composition may be determined. The PVA type has a vinyl acetate/2-ethylhexyl acrylate copolymer binder. The acrylic is a methyl methacrylate/butyl acrylate copolymer. The alkyd enamel is an orthophthalic alkyd type, and the epoxy is a bisphenol A type. 

FIGURE 8.5 THM chromatogram of an architectural alkyd enamel. G3ME = glycerol trimethyl ether, P4ME = pentaerythritol tetramethyl ether, P3ME = pentaerythiitol trimethyl ether, DMOP = dimethyl orthophthalate, AZ = methyl azelate, C,5o = methyl palmitate, C,go = methyl stearate. 

Studies on the differentiation between alkyd enamels by conventional Py-GC have been carried out. As discussed previously, more structural information about alkyd enamels may be obtained by the THM technique. Polybasic acid, polyhydric alcohol, drying oil composition, oil length, degree of cure, and any rosin modification can be determined. The discrimination between alkyd enamels is therefore improved. For example, the alkyd enamel whose pyrogram is shown in Figure 8.4 gives the THM profile shown in Figure 8.5. 

It can be concluded that the beverage can coating is a methyl melhacrylate/eth-ylhexyl acrylate copolymer modified polyester. The polyester is an adipic acid-modified neopentyl glycol iso-/orthophthalic acid type. The electrical appliance coating is a butylated amino resin cross-linked pentaerythritol-orlhophthalic thermosetting alkyd enamel. 

This terpine ether known as terpinyl methyl ether is a light, colored liquid with a pleasant odor, which contains some impurities. It is a strong solvent for resins and is used in alkyd enamels to the extent of 2 per cent to which it imparts flow. 

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