Acrylic A type of resin used in solvent borne and waterborne industrial and decorative coatings and inks. Often reacted with other resin types to achieve the right properties.
Additive A liquid or powder added in small, carefully controlled quantities to a coating, usually in production, which makes important, changes to the performance of the coating in application and/or performance. Their uses include keeping heavy pigments for settling, speeding up drying, preventing skinning in the can, adjusting electrical conductivity for spraying, helping film flow, making the surface of the film more or less slippery, slowing down weathering and reducing smell.
Adhesion With the exception of strippable coatings used for the temporary protection of polished metal, coatings must have good adhesion, sticking to the substrate despite knocks and atmospheric attack. Adhesion on a porous substrate such as paper may require the binder to be partly carried into the substrate to seal it. Substrates should be thoroughly clean for maximum adhesion, and may need a degree of surface roughness to be provided, as, for example, when domestic gloss paint is rubbed down with abrasive paper or steel is shot blasted before coating.
Air Drying A coating system, which dries at normal temperatures. Some dry just by the evaporation of solvents, whilst others also cure by reaction with the oxygen in the air.
Alkyd A type of resin used particularly in decorative gloss paints some (generally lower performance) industrial coatings and inks. It may air dry or to be staved to cure. It is generally solvent borne, but can be used in water born systems.
Attritor A piece of dispersion equipment which can quickly disperse some liquid coatings in a single operation. Filled with small ceramic or steel beads, the coating is loaded and ground in the beads by a rotating impeller. The heat generated is removed by a water jacket.
Bead Mill A piece of secondary dispersion equipment for liquid coatings in which the coating, pre-dispersed on a high speed mixer, is pumped through a tube packed with beads rotated by a central agitator. The tube may have its axis vertical or horizontal, and is cooled by water to keep the temperature controlled. More viscous products can be processed in similar 'rod mills' in which the beads are replaced by a number of steel rods lying parallel to the axis of rotation of the main shaft.
Binder A binder is generally a "resin", a high molecular weight hydrocarbon which forms the integral film of a coating by curing. Resins may be thermoplastic (PVC), which means that they can be cycled through solidifying/softening without significant chemical change; or they may be thermosetting (e.g. epoxy) resins which change their chemical structure on curing to a solid film which cannot be re-melted. A few binders are wholly or partly inorganic, such as cement or ethyl zinc silicate.
Blade Mixer A primary dispersion machine for viscous coatings and pastes. Litho inks, putties and fillers are commonly processed. One or more blades - often of a 'Z' shape, rotate and knead the paste. Dissipating heat is difficult, so the process can be slow.
British Coatings Federation (BCF) The British Coatings Federation is the trade association for the paint and ink industry of the United Kingdom. BCF promotes the interest of the industry, and provides and interface between companies, government, other organisations and the general public.
CEPE The pan-European trade association of the coatings industry, the Confederation European des Associations de Fabricants de Pientures, d'Encres d'Impriemerie et de Couleurs d'Art includes as sits members the national trade associations and, as Corporate Associate Members, many of the major pan-European coatings producers. It promotes the interests of the industry, particularly with the Community and other international organisations. Health, safety and environmental issues are of particular concern.
Chemical Resistance Some coatings have to be used in interior or exterior situations in which they have a resist chemical attack on themselves and protect the substrate from attack. Epoxy resins are frequently used as the binder for such coatings. An associated problem is stain resistance, particularly important in white goods and other equipment to be exposed to curries and pickles.
Classifying A process of grading particles of power according to particle size. Sieves or air vortexes may be used, particularly to remove 'fines' that may cause problems in application equipment.
Coating System Two or more layers of coatings, generally different coatings serving different purposes: for example, suitable pre-treatment followed by a primer to provide adhesion and corrosion resistance, then an undercoat to obliterate and bring the colour closer to the final shade required, and a topcoat to provide the aesthetic appearance over the life of the coating.
Coil Coating Painting (and/or laminating with sheet plastic) metal in coil from before forming the metal into cladding or finished components. Also known as refinishing.
Construction The construction market is made up of users who coat new articles and components for use by the construction industry. Metal and wood are the main materials that are coated. Articles produced include cladding for walls and roofs (often coil coated), windows and joinery. Most coatings are spray applied or coil coated. Curing is generally by stoving for smaller items, and by air drying for larger items.
Correct Colour On some coatings systems, such as primers and undercoats, high levels of colour accuracy are not important. In most topcoats and inks, however, accurate colour is vital, and the aim is always to keep consistency of colour between batches, as well as matching the standard. On each batch, therefore, the aim is to set the colour between the last batch and the standard. Colours may be compared by eye using various standard illuminations in a light cabinet. More usually they are also compared using colour computers, which can not only measure the closeness of the match, but can calculate the amounts of stainers required to improve the match to the standard colour. A key problem in matching colours is to make sure that the match is acceptable, not just in daylight but also in, say artificial light. Colours that match in one light but do not match in other lights are said to show metamerism.
Corrosion The process of oxidisation of a metal, generally, for paint makers, steel or aluminium. Seen on iron or steel as rusting, it may be accelerated by moisture or chemical in the air. It has been estimated that the annual cost of corrosion in the UK alone is about £3 bn. A year.
Corrosion Resistance The ability of a coating system to slow corrosion, often achieved by the inclusion of pigments based on metallic zinc or compounds of zinc, lead or calcium. Good adhesion and water resistance of the coating is generally also important, to prevent access of moisture to the metal substrate. Other systems offer corrosion resistance such as coating with zinc (galvanising), and may be used on their own or in conjunction with a coating system.
Cross-link The process by which polymers become interlinked to form a solid, three-dimensional matrix. Chemical bonds are formed between neighbouring molecules of the polymer(s) present, by allowing them into contact by evaporation of solvent; or by heating; or by chemical reaction using a cross-linking agent.
Curing Converting the wet or powder applied coating to a dry, continuous film by the application of heat, a reactive chemical, some form of radiation or atmospheric action.
Curtain Coating A method of applying a liquid industrial coating by passing a substrate (which is usually flat) at a steady speed under a 'curtain' of the coating.
Cyclone A Machine into which powder coatings are blown during manufacture, which uses an air vortex to separate oversized particles (which drop through the centre), undersized powder dust (which is blown out of the current of air) and powder of the correct particle size, which is collected for packing.
Decorative The decorative paint market in the UK buys more than 300 million litres of paint each year, valued at over £500 million. European users consumer almost 2.5 billion litres per year. Products are designed for either interior or exterior use, although "exterior use" products can be used in interior applications. Products specifically for interior use include emulsion paints for walls and ceilings and a variety of special paints for specific applications such as in kitchens or bathrooms. Products for exterior use include gloss and masonry paint, and a wide range of varnishes and stains for wood care. The market is made up of DIY and Trade users.
Diluent A liquid part of wet paint which does not contribute as a solvent to dissolving the resin, but nevertheless reduces the viscosity of the paint to help with application.
Distile A process for separating a mixture of liquids, during which the liquid mixture of substances is boiled, and the vapour escaping is condensed and collected. The early material collected will be the lowest boiling point component of the original mixture, whilst later materials will be of a higher boiling point.
Distributor A business, which may or may not be owned by the coatings manufacturer, which distributes coatings and other materials, used by its target industry. They are particularly important in distributing vehicle refinish and yacht paints, and is important for marine paints, litho and screen inks. Trade paints distributed through a variety of shops and stores.
Dry Dock A dock with closing doors into which large ships can sail and from which the water can be pumped or drained out. Essential for substantial engineering works below the water line, in particular for painting with anti-fouling paint.
Electro coat A type of waterborne primer for metal surfaces which is applied by immersing the substrate in the paint and applying an electric charge to it. Used primarily in the automotive industries.
Describes a process in which something acquires an electrical charge and is as a result attracted to an article of opposite charge, or replaced by an object with the same charge. In coatings industries this property is usually used in the application of both powder and wet paints, and in ink jet printing. The coatings particles are electrically charged as they leave the gun/jet head and are attracted to the earthen substrate. As the coating thickness builds up on the substrate, its attractiveness to the coatings particles diminishes and, especially with powder a fairly even film thickness can be achieved.
Emulsion A stable mixture of two liquids, which will not dissolve in one another. In making emulsion paint, water and various solvents, which mix with water are the 'continuous phase' which holds tiny droplets of liquid resin polymer dispersed.
Engineering The engineering market is made up of users who coat articles and components fabricated out of metal. Powder coatings are frequently used, as well as wet paint. Some primers are applied by dipping, but most coatings are sprays applied.
Environmental Science Scientific study of environmental issues. It is important to achieve objectivity and the best possible solution to environmental science is a developing branch of science, which studies the environmental impacts of products, processes and their alternatives. It includes life cycle analysis, which examines the environmental impact of products from their cradle to the grave.
Evaporation Occurs when part of the liquid in a coating becomes a vapour (either at normal temperatures or with heating) and disperses, generally in the atmosphere.
Film The process of removing solid and semi-solid impurities from a liquid coating by use of paper or cloth filters. One of the important jobs of a paint maker is to prevent the impurities getting there in the first place.
Flexibility Most substrates move - paper and plastics demand that inks be particularly flexible - but even wood, steel and concrete move with temperature changes or when the surface is knocked. Brittle coatings which fly off at times like this would be useless. Some resins are naturally more flexible than others and may be used in blends to give the coating flexibility. Additives called plasticisers are also often used. Care, however, is need to balance out the amount of flexibility in the formulation with other properties of the coating such as hardness and ease of cleaning.
Flexographic (Flexo) Flexo printing is a form of relief printing which uses a flexible plate. Firstly ink is transferred from the ink bath to the printing plate via the anilox roller. The substrate, which is usually plastic film or carton board for the printing industry, is fed from a reel through the machine in a continuous web.
Furniture The furniture market is made up users who coat wooden furniture using clear or pigmented coatings. Coatings may be applied by roller, spray or curtain, and are cured by air drying, heat or UV.
Gloss The proportion of light reflected from a beam of light falling at an angle on the surface. Gloss may be reduced by increasing pigmentation, changing the types of pigment used (for example, by the use of matting agents), or by chemical additives.
Gravure The image area is etched or engraved into the metal surface of a printing cylinder. These etched "ducts" are filled with ink as the cylinder rotates. Excess ink is removed from the non-image area with a doctor blade. Ink is transferred to the substrate by the pressure between the printing cylinder and the impression roller.
Hardness Coatings should not scratch or mark easily. The most extreme example is paints for the bows of icebreakers, which use extremely hard pigments to enable them to stand up to months of cutting through pack ice. Another form of marking can occur when coatings rub together, particularly in printing and packaging applications. Rub resistance may be improved by using small amounts of waxes as additives.
Health & Safety Data Sheets A document providing storage and handling instructions for raw materials and finished trade and industrial coatings, and inks. Particular hazards, if any will be described in detail, together with first aid instructions.
High Solids Coatings in which the solid or potentially solid parts (mainly resins and pigments) from a large part (usually over 75%) of the coating's volume.
High Speed Disperser A powerful mixer for liquid coatings, which can be used for primary or complete dispersion, depending on the coating involved. A vertical shaft with a blade (which may be in a specially designed cage) can be lowered into the mixture of resins, thinners and pigments. Rotating at high speed, the blade, if positioned at the right height, can create a severe vortex, circulating the coating and dispersing the pigments.
Industrial The industrial paint market in the UK buys nearly 300 million litres of paint each year, valued at over £700 million. European users consume over 1.6 billion litres each year. Products are often designed for users' specific applications, tailored specifically for the method of application and curing to be used, as well as for the end use of the cured coating. The market is very diverse, but further details of groups of users can be found under Protective coatings, Marine, Transport, Engineering, Construction, Furniture, Plastics, Electronics and Packaging.
Ink Jet Printing Ink jet printing is a non-impact process - no pressure is applied to the substrate. A jet ink is fired from a "gun"! and is broken up into a stream of minute droplets of ink. These are all electronically charged to a predetermined level before passing between deflector plates which alter their individual flight paths to the substrate, and so forming the required image. Because it is non-impact, this process can print on almost any surface.
Inks The ink market in the UK buys more than 120,000 tonnes of ink each year, valued at over £350 million. Major users include the Publishing and Packaging industries. There is a wide range of smaller users supplied by general and specialist printers, such as the commercial and promotion markets.
Insulation The insulation market is made up of users who manufacture electrical and electronic products in which the electrical conductors must be insulated to contain the electric currents flowing through them. Special varnishes are applied in ways which ensure complete coverage, and generally cured with moderate heat. Optical fibres also need special coatings, as do the casings of electronic eq2uipment to screen the equipment from electromagnetic radiation.
Let Down Tanks Are mixing tanks with a relatively slow agitation in which liquid coatings can be adjusted to the correct viscosity and other properties.
Letterpress The oldest and simplest of all the printing processes. It is a "relief process", with the image area standing out of the printing plate. Paper is then placed directly onto the inked relief surface, and by applying pressure the ink on the plate transfers from the image to the substrate.
