232 9. Properties and Testing humidity, tollowed by 16 h at 23°C and 50% relative humidity, and two days of ambient conditions (VDA Guideline 621-41 5). Since atmospheric corrosion is an electrochemical process, attempts have been made to develop electrochemical test methods that can predict the corrosion resis- tance of the coating-substrate system [9.41], [9.42]. The specimens are damaged with a scratch that exposes the metallic substrate, and are cathodically polarized. After several hours a loss of adhesion at the scratch can be observed. which can be correlated with natural corrosion. Resistance to Liquids. Various methods are used to test the resistance of coatings to the action of liquids and pastes (e.g., mustard, soap solutions, ketchup). Standard methods are defined in IS0 281 2. Coated specimen panels are partially immersed in the test liquid so that the changes in gloss, color, and swelling can also be evaluated at the liquid-air interface. Disks of absorbent material are immersed in the test liquid and placed on the coating. The test liquid or test paste is also dropped directly onto the coating. If the test medium is to be prevented from evaporating, the test surface is covered with a glass dish. Elevated temperature generally increases the aggressiveness of the test medium. IS04628 describes a general system for evaluating the decomposition of coatings. The intensity, quantity, and size of common defects are classified on a numerical scale ranging from 0 to 5. 9.2.5. Weathering Tests Coatings that are exposed to weathering undergo aging. Aging is defined as the sum of all irreversible chemical and physical processes that occur in the coating over the course of time. Aging is mainly caused by radiation, temperature, and moisture (rain and atmospheric humidity). Solar radiation (A = 290-3000 nm) is the primary cause of aging. Solar radiation causes heating of the coating that depends on the color of the surface. UV radiation initiates photochemical aging. Weathering produces changes in gloss and color, cracking, blistering, loss of adhesion, and loss of flexibility; these parameters are used to evaluate aging [9.43]-[9.48]. IS0 2810 gives guidelines on how to perform natural weathering tests. The manner and location in which the coating is exposed must be appropriate for the end use of the product under test. Flat specimen panels or structures are fastened to exposure racks at a defined angle. The exposure period should be one or more years. The intensity, quantity, and magnitude of defects (e.g., blistering, chalking, cracking) caused by natural weathering can be classified accord- ing to IS04628 (evaluation of degradation of paint coatings). Measurement of degradation of gloss and color is described in Section 8.2.2. Commercial test institutes in Florida are often commissioned to carry out natural weathering tests. The weather conditions in Florida are preferred because the same aging phenomena occur as in other locations but more quickly. Exposure time can be reduced by a factor of two to four when compared with other locations. The test 9.2. Properties of Corrtings 233 institutes in Florida also offer accelerated aging by means of exposure on black boxes and on heated black boxes. In laboratories, coatings are artificially weathered in specially designed apparatus to simulate or measure the aging processes that occur during natural weathering. Artificial weathering involves a smaller number of parameters than natural weather- ing but can be controlled more uniformly and allows accelerated test conditions Generally valid correlations between aging processes during artificial and natural weathering cannot be expected because they are influenced by many factors. Clearly defined relationships can only be expected if the most important parameters are the same or their influence on the coatings is known [9.52], [9.53]. IS04892 and 11 341 specify filtered xenon arc radiation and other conditions used for the artificial weathering of coatings. The optical radiation source and its filter system is specified so as to produce a spectral distribution of the irradiance sufficiently similar to the global solar radiation defined in CIE Publication No. 85. The irradiance is measured inside the apparatus with a radiation meter. The temperature is measured with a black standard thermometer. The test panels are wetted by spraying or flooding with water. IS02809 and 787/15 also provide information on how to simulate aging processes occurring during natural weathering under a glass cover. ASTM D 822 describes a standard procedure for operating light- and water-expo- sure apparatus (carbon-arc type) for testing coatings. ASTM G 53 and DIN 53 384 describe similar standard procedures for the light exposure or light and water expo- sure (fluorescent UV type) of nonmetallic materials [9.54]. [9.49]-[9.51]. 10. Analysis Modern coating materials are complex mixtures of binders, solvents, pigments, extenders, and additives. Most of these components consist of several constituents. Complete analysis of coating materials therefore requires comprehensive knowledge and the use of various analytical methods. Surveys of the analysis of coating materials are given in [10.1]-[10.3]. The pro- ceedings of conferences devoted specifically to paints (e.g., FATIPEC, International Conference on Organic Coatings, Science and Technology in Athens, Waterborne and Higher-Solids Coatings Symposium, the conference of the ACS Polymeric Ma- terials Division, and ASTM meetings) are particularly important because they de- scribe the use of analytical methods from the point of view of their suitability for investigating coating materials. Periodic literature reviews on the analysis of coating materials are also published in the journal Analytical Cliemisrry. The analysis of coating materials is often employed in the investigation of com- plaints and substandard batches, or to evaluate competing products. Analysis also plays an important role in the assessment of raw materials, occupational safety and hygiene, and the emission of solvents and decomposition products during paint curing. In the case of complaints, the binder and pigment (extender) composition of the individual layers have to be established to determine the origin of the paint material in doubtful cases. Establishing the cause of coating defects (e.g., inclusions, delam- ination, peeling) is also important. These and other analytical investigations are time-consuming and expensive. Optimal utilization of analytical resources therefore requires a clear definition of the problem in hand. 10.1. Analysis of Coating Materials 10.1.1. Separation of the Coating Material into Individual Components For a complete analysis it is advantageous to separate the coating material into its components. The binder and pigment (extender) fractions can only be investigated in detail after separation and isolation. The solvent composition can usually be determined by gas chromatographic analysis of the complete coating material. The Paints, Coatings and Solvents Second, Completely Revised Edition Dieter Stoye, Werner Freitag copyright 0 WILEY-VCH Verlae CirnhH. IYYX pigment (extender) fraction is centrifuged off after diluting the coating material with a suitable, volatile solvent (ethyl acetate, tetrahydrofuran, methyl ethyl ketone) [10.2]. Centrifuge speeds of 5000 min- ' are generally sufficient, however if finely divided pigments (extenders) or soot are present, a low-density, low-viscosity solvent (e.g., acetone) should be used and the rotational speed should be increased to 20000 min- ' [10.4]. To achieve quantitative separation the pigment sediment is repeatedly shaken with solvent and recentrifuged. Prior to analysis the combined binder containing supernatant fractions are dried in a drying cabinet. The cen- trifuged pigment is also dried in a drying cabinet before being analyzed. Problems are often encountered if centrifugation is applied to waterborne systems, particularly if the binder is insoluble or only sparingly soluble in organic solvents. In these cases the coating material should be carefully dried (vacuum drying cabinet, freeze drying). A representative binder fraction is then obtained by exhaustive ex- traction with a suitable solvent (e.g., 1,2-dichIorobenzene. dimethylformamide and/ or tetrahydrofuran) [ 10.51, [10.6]. For some microgel-containing waterborne sys- tems the use of an isopropanol-water-mixture leads to a rather complete separation of pigment and binder, since the microgel remains in the supernatent. 10.1.2. Analysis of Binders Modern coatings are expected to provide permanent protective action, outstand- ing mechanical ~ technological properties, and an attractive surface appearance. This requires binders consisting of special resin combinations (Chap. 2) and selected additives (Chap. 5). Preliminary tests, color reactions, and spot tests [10.7] were formerly used to identify individual resins but are no longer important because they are not sufficient- ly specific and they do not provide quantitative results. They have been largely replaced by modern spectroscopic and chromatographic methods, which often re- quire preliminary chemical workup of the sample. Infrared and nuclear magnetic resonance spectroscopy are the most important spectroscopic methods for analyzing coating materials. Near infrared Fourier trans- form (NIRFT) Raman spectroscopy [10.8] also has great potential, particularly for aqueous systems. UVjVIS spectroscopy is used only in exceptional cases, e.g., to determine light protection agents (UV absorbers). Infrared spectroscopy has the advantage of simple sample preparation and mea- surement; practically all types of samples (both as regards the state of aggregation and solubility) can be investigated with the aid of special measuring techniques. Infrared spectroscopy is frequently employed to obtain an overview of the binders and binder classes. A common procedure is to pour a few drops of the binder-con- taining supernatant from the separation (centrifugation) onto a NaCl or KBr crys- tal. A thin binder film is obtained after drying in the drying cabinet and IR absorp- tion is then measured. The IR spectra provide qualitative and semiquantitative information about the binder composition. Comprehensive spectra catalogs of or- 10.1. Atiulysis qf'couting Muteriuls 237 ganic polymers [10.9] and commercially available coating materials [10.10] are avail- able for comparison purposes. Modern IR spectrometers, particularly the Fourier transform infrared (FTIR) spectrometers, offer further possibilities. These instru- ments have short measurement times and high wavelength reproducibility; they can therefore accumulate data and provide a considerably better signal to noise ratio than conventional grating or prism instruments. IR spectroscopy can then be used to analyze extremely small sample amounts. Examples are diffuse reflectance FTIR spectroscopy (DRIFTS), investigations of sample surfaces by measurement with attenuated total reflection (ATR), or the analysis of local defects using an IR micro- scope [10.11]. A further advantage of FT spectrometers is the fact that the data are available in digital form. Spectroscopic data banks can therefore be compiled either on the spectrometer computer or on an external computer. Commercial data banks (e.g., Sadtler) and in-house, laboratory-specific data collections can be installed, the latter are often better suited to the particular interests of the laboratory. Data banks facilitate archiving, and also allow quick comparisons of measured and library spectra. Quantitative evaluations are also facilitated after appropriate calibration. The theoretical aspects of FTIR spectroscopy and analysis are described in [10.12]. The use of FT and conventional IR spectroscopy to investigate coatings and coating materials is described in [10.13]-[10.15]. Nuclear Magnetic Resonance Spectroscopy. Like IR spectroscopy, NMR spec- troscopy requires little sample preparation, and provides extremely detailed infor- mation on the composition of many resins. The only limitation is that the sample must be soluble in a deuterated solvent (e.g., deuterated chloroform, tetrahydro- furan, dimethylformamide). Commercial pulse Fourier transform NMR spectrome- ters with superconducting magnets (field strength 4- 14 Tesla) allow routine mea- surement of high-resolution 'H- and I3C-NMR spectra. Two-dimensional NMR techniques and other multipulse techniques (e.g., distortionless enhancement of polarization transfer, DEPT) can also be used [10.16]. These methods are employed to analyze complicated structures. I3C-NMR spectroscopy is particularly suitable for the qualitative analysis of individual resins in binders, quantiative evaluations are more readily obtained by 'H-NMR spectroscopy. Comprehensive information on NMR measurements and the assignment of the resonance lines are given in the literature, e.g., for branched polyesters [10.17], alkyd resins [10.18], polyacrylates [10.19], polyurethane elastomers [10.20], fatty acids [10.21], cycloaliphatic diiso- cyanates [10.22], and epoxy resins [10.23]. Chromatography. Liquid chromatography is the most important chromatograph- ic method for the investigation of binders and resins. Special applications are also opening up for the recently developed technique of supercritical fluid chromatogra- phy (SFC) [10.24]. Methods of particular importance are size exclusion chromatrog- raphy (SEC) (also termed gel permeation chromatography, GPC) and reverse-phase high performance liquid chromatography (HPLC). Gel permeation chromatography separates molecules according to their size. This technique is used to determine the molecular mass distribution of resins. A review of modern GPC methods for analyzing coating materials is given in [10.25]. Combina- tion of GPC with modern spectroscopic techniques (in particular FTIR spec- troscopy) is a valuable aid for identifying individual resins in binder systems; in some cases additives can also be identified, because their molecular mass is often substan- tially lower than that of the resin constituents. The coupling of liquid chromatogra- phy and FTIR spectroscopy is described in [10.26]. Off-line investigations of frac- tions from an analytical GPC run of a binder by FTIR measurements under diffuse reflection provide detailed information on the composition of the binder [10.27]. Reverse-phase HPLC (mainly octyl- or octadecyl-modified silica gels) separates molecules according to their partition coefficients. It is particularly suitable for characterizing relatively low molecular mass resins (e.g., epoxy, phenolic, and melamine resins). The high resolution of modern columns and the high sensitivity of UV detection allow individual oligomers (including positional isomers and secondary compounds) to be separated and identified. The peak distribution pattern often permits identifi- cation of commercial products. Detailed HPLC investigations have been carried out on epoxy resins [10.28]. HPLC can also be applied to resins without UV-active groups by using mass detectors [10.29]. On-line coupling of pyrolysis, gas chromatography, and mass spectrometry is a quick and elegant method for the qualitative detection of monomer units in many resins (e.g., polyesters, polyurethanes, phenolic resins, and polyacrylates). Identifica- tion of comonomers of polyacrylates, including hydroxy-functional and carboxy- functional monomers, is facilitated if the sample is silylated before pyrolysis [10.30]. Chemical Workup. Chemical decomposition of resins followed by qualitative and quantitative analysis is still an important technique because, apart from NMR spectroscopy, none of the instrumental analytical methods provides reliable quanti- tative values. Chemical workup is also essential for low concentrations of resin building blocks that are often unknown; it simplifies and enables the desired sub- stances to be concentrated. Qualitative and quantitative determination is carried out by instrumental methods. Well-established methods of chemical workup are available for alkyd resins based on o-phthalic acid. Alkaline hydrolysis can be used for the quantitative determina- tion of the dicarboxylic acid, fatty acid, and polyol fractions [10.31]. In the IUPAC method the carboxylic acids are determined by gas chromatography after transester- ification with lithium methoxide; the polyols are determined by gas chromatography after aminolysis and acetylation [10.32]. Chemical workup methods (e.g., hydrolysis with alcoholic alkali, alkali fusion, aminolysis with hydrazine, and transesterifica- tion with sodium methoxide) for various resins are described in [10.33]. Alkaline hydrolysis has the disadvantage that it results in low fractions for polyunsaturated fatty acids and lower polyols. Transesterification with methanol or trimethylsulfoni- um hydroxide provides substantially better results for unsaturated fatty acids. This transesterification process was originally proposed for determining fatty acids in triglycerides [I 0.341 but can also be applied to alkyd resins and polyesters. After evaporation of methanol and silylation, the polyols from the reaction mixtures can then be determined by gas chromatography. This procedure yields more accurate values than with the previously mentioned methods, particularly for the lower poly- 01s. In addition the amount of fatty acids and dicarboxylic acids can be determined with the help of gas chromatography by direct injection of the reaction mixture. 10.1.3. Analysis of Pigments and Extenders The separated pigment (extender) is usually used as starting material for analysis (see Section 10.1.1). If quantitative separation is not possible (e.g., in emulsion paints) the inorganic pigment (extender) fraction can be obtained by ashing the nonvolatile fraction; for further details see [10.5]. The isolated pigment (extender) fraction is analyzed by various chemical and instrumental methods. Methods of elemental analysis are used for inorganic pig- ments (extenders). These include traditional chemical methods involving separation and gravimetric, tritrimetric, or polarographic determination of the elements. These methods are being replaced by instrumental methods such as atomic absorption spectroscopy (AAS), atomic emission spectroscopy (AES), and X-ray fluorescence analysis (XFA). A further valuable tool is IR spectroscopy, which provides charac- teristic spectra for many inorganic extenders and pigments (e.g., chalk, dolomite, kaolin, talc, and barium sulfate). The most elegant and informative method, but the most expensive as regards equipment, is X-ray diffraction [10.35], [30.36]. Sample preparation is simple and the method can be used on hardened coating materials; problems associated with isolating the extender-pigment fraction can therefore be avoided. The principal advantage, however, is that the substances (e.g BaSO,) can be identified directly and not indirectly via their elements (e.g., Ba and S). This is particularly advantageous if both silica and silicates (kaolin, talc) are present. Min- erals such as dolomite, chalk, talc, and kaolin originating from different geograph- ical locations have specific elemental compositions. Their spectra can therefore be used to identify the source of supply when investigating coating materials [10.37]. For many inorganic and organic substances, X-ray diffraction spectra recorded on powdered materials are commercially available on a data carrier (CD-ROM) [10.38]. The pigmentation of monochrome coating materials usually comprises several constituents: organic and/or inorganic pigments, titanium dioxide to improve the hiding power, and other inorganic extenders. The inorganic fraction is generally dissolved with acid and can then be analyzed by conventional chemical methods. For the investigation by atomic absorption or atomic emission spectroscopy a borax fusion is recommended as preparatory step. The organic pigments remain undis- solved and are investigated by IR spectroscopy, photometry, X-ray diffraction, and separation methods such as thin layer chromatography (TLC) or HPLC. Modern FTIR spectroscopic methods including library searches; further developments in TLC and HPLC are discussed in [10.39]. A separation process for organic pigments has been developed which exploits solubility differences in various solvents (ranging from n-hexane to sulfuric acid) [10.40]. The extracted pigments are identified by their VIS spectra in the range 400-900 nm. The advantages and limitations of X-ray diffractometry in the analysis of organic pigments are discussed in [10.41]. The increasing use of special-effect paints, particularly in automobile finishes, places new requirements on analytical techniques. The previously described methods are largely unsuitable for identifying substances used to produce special effects. Aluminum pigments in metallic paints can be roughly classified by light microscopy. Since these pigments are often subjected to special pretreatment, the determination of foreign elements with X-ray microprobes or the determination of an organic agent used for surface treatment may be necessary for more accurate characterization. Light microscopy can also be used for initial characterization of nacreous pigments, more detailed information can be obtained with a microscope spectral photometer (e.g., UMSP 80, Zeiss) or transmission electron microscopy [10.42]. 10.1.4. Analysis of Solvents The solvent composition of coating materials can be determined in two ways. In the first method, the coating material is subjected directly to gas chromatography, if necessary after dilution with a suitable solvent. In the second method, the solvent fraction is separated from the coating material by vacuum distillation and then analyzed by gas chromatography or, in special cases, by IR spectroscopy. ASTM methods (D3271 and D3272) exist for both processes. The advantages and disad- vantages of the two methods in the analysis of solventborne and waterborne systems are discussed in [10.2]. Direct gas chromatographic analysis with modern capillary column technology and reproducibly operating injection systems (e.g., modern autosamplers) gives highly reproducible, accurate results. This method is therefore used most widely. With complex solvent mixtures, unambiguous identification of the peaks is facilitat- ed by simultaneously analyzing the sample on two columns with different polarities or by using GC-MS. For further information on gas chromatography, see [10.43]. 10.1.5. Analysis of Additives Qualitative and, in particular, quantitative analysis of coating additives is difficult due to their low concentrations and chemical diversity. A general outline for their investigation cannot be given, isolation and analysis depend on chemical structure. The liquid or hardened coating material is often extracted with a suitable solvent, followed by spectroscopic or chromatographic analysis. For example, plasticizers can be extracted very efficiently with pentane and detected by IR spectroscopy or gas chromatography. Supercritical fluid chromatography (SFC) is being increasingly used for the analysis of polymer additives [10.44]. Especially in combination with supercritical fluid extraction (SFE) as a relatively fast and efficient sample prepara- tion method [10.45], it may prove to be of interest for the analysis of many additives used in coating materials. 10.2. Anuljsis of’ Coutings 241 10.2. Analysis of Coatings Coatings are practically free of solvents and the binder is generally cross-linked (i.e., insoluble). These factors require special sample preparation and analytical methods, for a detailed discussion see [10.46]. The separation of binder and pigment (extender) fractions for further investigation is only possible with non-cross-linked (physically drying) binders. The coating film is soaked in a suitable solvent and the pigment is centrifuged off after dissolving the binder. Provided sufficient material is available, the isolated components can be analyzed by the methods described in Section 10.1. The above method cannot be used with cross-linked binders (e.g., two-pack systems, stoving finishes). The binder and pigment (extender) fractions in coating layers are most simply analyzed by means of IR spectroscopy. Different measurement techniques are available for this purpose, which require various de- grees of preparative effort. The most important techniques are measurements on KBr pellets prepared from scratched off paint material, measurement of the coated surface with the method of attenuated total reflection (ATR), and measurements on cross sections of the coating with FTIR microspectroscopy [10.47]. Further methods for determining the binder structure of cross-linked systems include the use of pyrolysis gas chromatography or alkaline hydrolysis followed by analysis of the degradation products by gas chromatography. In multilayer coatings this may prove difficult because the materials have to be prepared from individual layers. The inorganic pigment (extender) fraction can be obtained by ashing the isolated paint material and analyzing it by the methods described in Section 10.1.3. The question of the cause of coating defects often arises in the investigation of coatings. Defects may be found at localized sites (specks, craters) and impair the appearance of the coating. They may also occur as planar defects that for example reduce adhesion to the substrate or between the individual layers. Defects are inves- tigated with light microscopy, FTIR microspectroscopy, X-ray methods [10.48], and modern surface analysis methods such as time-of-flight secondary ion mass spec- trometry (TOF-SIMS) [10.49], laser-microprobe mass analysis (LAMMA) [10.50], and X-ray photoelectron spectroscopy (XPS) [10.51]. Among the methods men- tioned TOF-SIMS proved to be the method of choice for the analysis of craters and other defects caused by surface-active substances [10.52]. 11. Uses The application of paints to various substrates (e.g., metals, wood, plastics, and concrete) is the most widely used method of protecting materials against corrosion and degradation. It is also used to obtain properties that include gloss, color, com- pletely smooth or textured surfaces, abrasion resistance, mar resistance, chemical resistance, and weather resistance. Normally, a combination of properties is re- quired. Paint systems are therefore applied that generally consist of a primer, an intermediate coat, and a topcoat. These coats of paint together with the substrate surface and surface layers resulting from substrate preparation and pretreatment form the coating system. Only this complete coating system can provide the combi- nation of properties required for the wide range of use? of organic coatings. Most paints are supplied as liquids that are applied by different methods, using various types of equipment (see Chap. 8). The properties and uses of powder coat- ings are described in Section 3.4. Once applied, the wet paint film must dry to a hard solid film. Paints that dry at ambient temperature (air-drying paints) may be force- dried at temperatures up to 100°C. Other types of paints require higher temperatures (1 20 ~ 220 "C) for film formation that involves reaction of two and more binder components. Thus, the paint formulator has to consider both the properties of the liquid film and those of the final dry film. Liquid film properties have to be consid- ered during storage, application, and curing. To obtain a properly formulated paint, testing has to be carried out in different stages (Chaps. 9 and 10): weathering and corrosion tests, application tests, field trials that test in-use behavior, and durability. The paints can only be used commer- cially when they have passed these tests. 1 1.1. Coating Systems for Corrosion Protection of Large Steel Constructions (Heavy-Duty Coatings) [I 1 .I], [I 1.21 Large steel constructions have vast metal surfaces which must be protected against corrosion to maintain their proper function. Such constructions include road and railroad bridges, electric pylon lines, radio and radar antennae, gas tanks, storage tanks (e.g., for oils, chemicals, cement, and grain), loading equipment (e.g., cranes, conveyors), mining and drilling constructions, as well as steelworks and chemical Paints, Coatings and Solvents Second, Completely Revised Edition Dieter Stoye, Werner Freitag copyright 0 WILEY-VCH Verlae CirnhH. IYYX [...]... polyurethane) and, more recently, coatings of acrylic resins which are applied as one-pack, waterborne dispersions Before applying the coatings, surfaces are pretreated by blasting Longlife coatings require surface pretreatment according to Swedish Standard SIS 055 900, grade 2 % (equivalent to DIN 559 28, part 4, FRG; BS7079, part A 1, 1 989 , U K ; SSPC-SP5-SP6, ASTM, USA; IS 085 01 -85 03) Engines and Passenger... important requirements and properties of exterior-use coatings on mineral substrates are the water permeability to water and water vapor and protection against carbon dioxide Aqueous systems such as silicate paints and vinyl or acrylic emulsion paints are suitable for opaque and semitransparent coatings Silicate paints have a high degree of hardness and good permeability to water vapor and gas Evaporation... be delayed by at least 10 min Paints, Coatings and Solvents Second, CompletelyRevised Edition Dieter Stoye, Werner Freitag copyright 0WILEY-VCH Verlae CirnhH I Y Y X 12 Environmental Protection and Toxicology Paints and coating materials frequently contain substances that may be a hazard both to human health and to the environment This applies particularly to organic solvents, to certain reactive binder... inorganic coatings, about 90% are coated with paints based on organic binders Appropriate surface preparation is of utmost importance for a long service life 2 Best results are achieved by blasting, using grade 2 Y or 3 according to the Swedish Standard SIS 055900 (equivalent to DIN 559 28, part 4, F R G ; BS7079, part A 1, 1 989 , U K ; SSPC-SP5-SP6, ASTM, USA; IS 085 01 -85 03) Although mill scale and old... (chemically drying) epoxy and polyurethane coatings, and a decline in the use of convertible (physically drying) acrylic, vinyl, or chlorinated rubber coatings for topsides and boottoppings Retention of color and gloss have been improved with rust-hiding antistaining additives (e.g., calcium etidronate or other iron(II1) sequestering agents) For similar reasons in the boottopping area and on decks, where... manufacture, surface preparation, and control and inspection of application The paints are generally applied by airless spraying Difficult geometrically complex areas and welds are usually cleaned, smoothed by mechanical abrasion, and coated with a brush [11.14]-[11.17] 11.4.3 Fouling and Antifouling Fouling and antifouling are unique to the marine industry In contrast to other coatings whose primary function... water Both waterborne and solventborne can coatings must not affect the can contents, especially their taste Components of coating films are not allowed to migrate into food, beverages, or other filling goods In most countries, food packaging is subjected to legal regulations The raw materials used to produce can coatings and the coatings themselves are strictly limited 11 .8 Furniture Coatings [I 1.I] The... wood Furniture coatings must therefore have excellent film flexibility as well as film hardness, and resistance to abrasion and fluids (e.g., alcohols) Prior to coating, wood surfaces usually have to be smoothed by sanding, using putty, patinating, staining, or pore filling Resins and essential oils are often extracted with organic solvents to prevent the coating from cracking, discoloring, and developing... spraying, machine roller coating, and curtain coating are used for industrial application of furniture coatings Drying is accelerated by air circulation and/ or increased temperature up to 80 “C IR drying ovens and tunnels are also used Furniture coatings can be clear or pigmented with many different color shades The surface can be high gloss, semigloss, matt, or textured Some coatings leave the wood pores... for indoor furniture and other wood parts These systems are still used on low-price furniture, but are gradually being replaced by coatings based on polyurethanes and unsaturated polyesters Most modern wood and furniture coatings are based on special acrylic resins and unsaturated polyester resins, cured by UV or electron-beam radiation [11.30], [11.31] The properties of furniture coatings can be summarized . ASTM D 82 2 describes a standard procedure for operating light- and water-expo- sure apparatus (carbon-arc type) for testing coatings. ASTM G 53 and DIN 53 384 describe similar standard. onshore and at sea). These coatings have excellent resistance to oil, solvents, and mechanical impact, and are therefore used on drilling stations, oil rigs, and ships. Since zinc-rich silicate coatings. according to the Swedish Standard SIS 055900 (equivalent to DIN 559 28, part 4, FRG; BS7079, part A 1, 1 989 , UK; SSPC-SP5-SP6, ASTM, USA; IS 085 01 -85 03). Although mill scale and old paint are sometimes