During electrostatic spray applications, electrical field lines, formed between spray gun and coated object, prevent the coating from reaching indentations. Process of formation of electrical field lines in a cage form preventing the transfer of coating to the inner surfaces of the cage is called the “Faraday Cage”.

Conjugated fatty acids

Fatty acids containing double bonds separated from each other by one single bond on their main molecule chain that is composed of carbon-carbon bonds. e.g., eleostearic acid, licanic acid etc.

Fatty acids

Acids that form oils by esterification with polyols. Majority of fatty acids are “vegetable fatty acids” which form vegetable oils by glycerol esterification. Monofunctional vegetable oils having 18 Carbon chain in their backbone are classified according to the number of C=C bond they have, as drying, semi-drying and non-drying. Fatty acids are widely used in paint industry for alkyd resin production.

See Food and Drug Administration

Food and Drug Administration (FDA)U.S institution that arranges the standarts, norms and recommendations regarding food and drug. FDA is an important foundation for coatings industry due to the standarts and limitations on coatings applied to food contact surfaces.

Roller that is positioned in the middle, among the three rollers in roller coating applications (pick-up roller, feeding roller and application roller).

See Also Roller coating applications

Pick-up roller

In roller coating applications, pick-up roller immersed in a paint pan, moves around its axis and transfers the paint on its surface as a film. See Also Roller coating applications

Feeding roller

Roller that is positioned in the middle, among the three rollers in roller coating applications (pick-up roller, feeding roller and application roller). See Also Roller coating applications

Application roller

Name of the roller which transfers the paint to the sheet to be coated on the conveyor belt. If the application roller runs in the same direction (at different speed) with the conveyor line, the process is called direct roller application, if roller runs in the opposite direction it is called reverse roller application. See Also Direct roller application, Reverse roller application

Roller coating applications

Paint application performed by using three parallel rollers named as pick-up, feeding and applicator. Pick-up roller immersed in paint pan, moves around its axis and transfers the paint to the feeding roller which it is in touch with. Feeding roller transfers the paint to the applicator roller in contact with it. Application roller, transfers the coating onto the material to be coated which is moving on a conveyor belt. See Also Direct roller application, Reverse roller application

Formation of a highly adhering, hard and enduring film as a result of physical (solvent evaporation for wet coatings, cooling for powder coatings) and/or chemical processes after application of wet or powder coating to the surface as a thin layer.

Organic coating raw material used for providing adhesion, internal integrity and strength. See Also Binder

Binder

Chemical substance used to bind the input materials in the organic coating and provide adhesion of the coating film to the application surface as a rigid and continuous film. Binders commonly have polymeric structures, while, less commonly, they may have oligomeric or monomeric structures.

Strike in

Coating defect described by dull or blurry appearance of topcoat due to the migration of some of the binder to the previous wet paint layer in wet on wet applications.

Solid binder content

Amount of solvent-free binder present in 100 units of wet paint or binder solution.

Latex binders

Binders produced by stable dispersion of solid polymer particles, primarily, natural and synthetic rubber in water.

Pigment/binder ratio

The ratio by weight of pigment content to solid binder content in paint formulation. See Also Solid binder content

Silicate based binders

Alkali metal silicates like sodium and potassium silicates have limited use as inorganic paint binder. Furthermore, ethyl silicate is used as a binder in anti-corrosive paints, especially in high corrosion resistant zinc-rich primers.

In-depth filtration

In-depth filtration is performed using porous filtration media (e.g, porous cartridges) with a thickness much higher than the desired particle size in the paint. Undesired particles are held in the pores of the filter and, thus the paint is filtered.

Filtration by cartridge filters

Filtration of coatings with “deep filtration method” under an applied pressure using cartridge filters having controlled porous structures. Presently, cartridge filters of 1µm to 100µm pore sizes are used for paint filtration processes.

Filtration

Mechanical separation of solid particles from fluid medium through a sieve which limits certain particle size to pass. See Also Surface filtration, In-depth filtration

Surface filtration

A process in which unwanted particles presented in paint are retained on a certain mesh size sieve.

Filtration of coatings with “deep filtration method” under an applied pressure using cartridge filters having controlled porous structures. Presently, cartridge filters of 1µm to 100µm pore sizes are used for paint filtration processes.

Upper limit of particle size range obtained after dispersion. Fineness of grind is usually stated using two gauges: Metric gauge based on micrometer and Hegman gauge. e.g, in the case that almost all the particles in a pigment paste or coating are 25µm or smaller, fineness of grind is 25µm in metric gauge and 6 in Hegman gauge.

Coating defect described by the crater appearance caused by a fluid having a lower surface tension than the coating system. In fish eye defect, there should be no solid residue observed in the center of the crater, which is usually caused by an oil or silicon droplet, or an undissolved lump of polymer.

The temperature at which a solvent, solvent mixture or solvent borne paint is heated so that it ignites with a spark. Flash point test performed by introducing spark to a heated solvent contained in an open cup is called “open cup flash point test”, whereas if spark is introduced to solvent in a closed cup is called “closed cup flash point test”.

Process of keeping the oven-baked wet paint at a lower temperature before baking, to ensure that fast evaporating solvents leave the coating film. Also called “pre-drying”.

Floating is a term used to describe a mottled, splotchy or streaked appearance exhibited by a paint film. Floating is due to separation and uneven distribution of different pigments in the paint. Difference between floating and flooding is that, in flooding color varies along the depth of the film and the film appears uniform horizontally,owing to migration of one or several pigments to the surface. On the other hand, in floating, changes are localized on the panel and color is not uniform horizontally.

Flooding

It is used to specify a color change along the depth of the film due to the migration of one or several pigments to the surface more than other pigments. When rub-out test is performed on a wet paint film with flooding, one can see an indistinct color change on the rubbed region by looking the paint-glass interface behind the glass. On the other hand, a more certain color change can be seen at paint-air interface.

Pigment lump formed by coalescence of pigments at their edges and containing resin and solvent in their interspaces. Flocculates generally arise from re-agglomeration of previously dispersed pigment particles. See Also Clusters of pigments and extenders

Although pigments and extenders are produced as primary particles, they form aggregates and agglomerates when they are in touch with each other in bulk phase. In dispersion stage, these pigment clusters are tried to break down to primary particles. If dispersed pigments are not stable, they form loosely combined units called flocculates. Since, the distinction between these three terms might not be clear, for a better understanding a schematic representation is given below.

Deflocculation

Grinding of pigment agglomerates and aggregates close to their primary particle sizes after dispersion process. See Also Controlled flocculation

Pigment particles undergo controlled flocculation with the help of dispersion additives that hold on to the pigment particles over their pigment-loving groups. Bigger particle sizes are obtained compared to deflocculation; however, “hard precipitation” tendency of the coating decreases. Controlled flocculation is a widely used technique during dispersion of primer pigments and fillers.

Flocculation

Agglomeration of previously grinded and dispersed pigments as flocculates due to the unstable dispersion process. See Also Flocculate

Pigment lump formed by coalescence of pigments at their edges and containing resin and solvent in their interspaces. Flocculates generally arise from re-agglomeration of previously dispersed pigment particles. See Also Clusters of pigments and extenders
 

It is used to specify a color change along the depth of the film due to the migration of one or several pigments to the surface more than other pigments. When rub-out test is performed on a wet paint film with flooding, one can see an indistinct color change on the rubbed region by looking the paint-glass interface behind the glass. On the other hand, a more certain color change can be seen at paint-air interface.

Application of coating to the surface by pouring the coating by means of a hose etc. Coating is then collected in a bottom container to be pumped back to flow coating process.

Cylindrical cups, of generally 100 ml inner volume, with flat or conical bases and holes at the bottom, used to measure fluid viscosity. There are various flow cups defined by various standards (e.g. DIN cups, ISO cups, Ford cups, Afnor cups, Iwata cups)

Most of the colored objects absorb some of the light they are exposed to and reflect the rest, while they return the light energy they absorbed to the surrounding in the form of heat energy. There are few objects, however, that return the light energy in the form of light energy. This fact is called flourescence.

Flourescent pigments, after absorbing the UV spectral part of the light, return the UV light energy in the form of a blue visible light together with some heat energy. Therefore, flourescent pigments emit more visible light than they are exposed to.

Similar to polysiloxane surface additives; fluorocarbon surface additives, having low surface tensions and compatibility with the coating formulation, migrate to the surface to avoid formation of film defects.

General name for polymers, structural units of which contain fluoro compounds. Polytetra fluoroethylene (PTFE), polyvinylidendifloride (PVDF or PVF2) and polyvinylidenfloride (PVF) can be mentioned among the main fluoropolymers that are used in organic coatings having superior thermal resistance, chemical resistance and outdoor durability.

Foam stability is defined as the resistance of bubbles, caused by air trapped in the wet coating during production or application, against bursting and disappearing. It is known that silicon additives increase the foam stability if they are highly compatible with the coating and they effectively decrease the surface tension.

U.S institution that arranges the standarts, norms and recommendations regarding food and drug. FDA is an important foundation for coatings industry due to the standarts and limitations on coatings applied to food contact surfaces.

Butylated melamine formaldehyde resins

Melamine formaldehyde resins modified by reacting with butanol. Butylated melamine formaldehyde resins are widely used because of their compatibility and high film quality due to their comparably low surface tension. However, they are not used in high solid systems because of their high molecular weights.

Formaldehyde

Reactive gas obtained by catalitic oxidation or dehydrogenetion of methanol

 .
Basic structural unit used in production of various resins such as melamine formaldehyde, urea formaldehyde, phenol formaldehyde etc.
Chemical formula: 
Boiling point: –21°C
See Also Paraformaldehyde

Hexamethoxymethylated melamine formaldehyde (HMMM) resins

Monomeric melamine formaldeyde subjected to complete etherification with methanol. Its low molecular weight and solubility in both water and organic solvents enables its usage as high solid content coating input. Because it is completely etherified, acid catalysts need to be added to the coating formulations in order to enhance the reaction tendency, which is lower compared to butylated melamine formaldehyde resins.

Melamine formaldehyde resins

Polymerization products of melamine and formaldehyde. They are the most common cross linkers in baking systems. Melamine formaldehyde resins are modified with various alcohols to increase solubility in paint solvents and compatibility with polymers.

Paraformaldehyde

A polymer consists of 10 to 100 formaldehyde units. Not only the hazardous effects to human health and environment but also the difficulties in processing and storing of formaldehyde gas leads to paraformaldehyde use in formaldehyde resins. Paraformaldehyde decomposes into the formaldehyde at nearly 150°C.
Chemical formula:

Urea formaldehyde resins

Polymerization product of urea and formaldehyde. Commonly used as adhesives. In addition, they are used as cross-linker in alkyd and polyester baking systems.

Frame-like appearance caused by higher coating thickness on the edges of the coated object. This is due to the fact that there is more interface on the edges, therefore evaporation occurs faster on the edges. Since solvents have lower surface tension values than the rest of the paint formulation, surface tension of the remaining wet film is higher at edges, and consequently, paint accumulation occurs on these parts. See Also Maragoni effect

The most common type of addition polymerization. Monomers transform into free radicals and become activated with the help of an initiator and the polymerization starts.

The volume, which is excluded from the volume occupied by the molecules in the total bulk volume of polymer and its solution.

General name for groups formed by atoms, present in the structure of a chemical compound, arranged together to have tendency to undergo chemical reactions. (e.g., –OH, –COOH, –NCO, –HC=CH–)

Functionality is the total number of functional groups in the molecule of a chemical compound (total capacity for chemical bonding).