Glossary
The aim of the glossary is to provide a general introduction to topics related to plastic coatings.
The glossary is intended to provide an introduction to the topic. It makes no claim to completeness or absolute correctness of the current state of scientific knowledge.
The contents are non-binding and for information purposes only.
With a non-stick coating, the product separates well from the substrate. In the case of water, the surface is then described as hydrophobic (water-repellent), in the case of oil as oliophobic (oil-repellent).
In the consumer sector, non-stick coatings are widely used in baking and frying utensils so that the fried egg does not stick to the pan and the bread slips easily out of the mould after baking.
Non-stick coatings are used in industry, e.g. so that the plastic does not stick to the welding tool or the dough detaches easily in the dough funnel.
ChemLINE 784® is a corrosion protection coating; a registered word mark of HÜNI + CO in the EU economic area (European Union).
At relatively low curing temperatures, the coating offers high corrosion protection against a wide range of chemicals.
The ChemLINE 784® coating is applied, for example, in tanks and tank containers. The coating material is a product of Advanced Polymer Coatings (Ohio, USA; www.adv-polymer.com).
Diffusion is the thermal movement of atoms, molecules or charge carriers; referred to here as particles. They migrate from areas of high concentration to areas of low concentration.
If, for example, a plastic is not sufficiently pore-tight for a chemical, particles penetrate into the plastic wall or coating of a container for chemicals. The particles fill the plastic, resulting in an increase in weight; the plastic swells. The extent of the weight increase or swelling provides an indicator for short-term resistance analyses, which is used to calculate the long-term determination of diffusion resistance.
In the second stage, the particles are deposited or flow outside. If a subsequent "pore-tight" material, e.g. a metal container wall, prevents further penetration, the particles collect in the gap. In the case of a plastic-coated metal container, bubbles form under the coating. If the outer, enclosing material, in this case metal, is not chemically resistant to the particles (chemicals), the result is corrosion or even leakage.
The diffusion resistance of a material, in this case a plastic coating, depends, among other things, on its thickness, but also on the molecular density and bonding properties of the molecules or atoms.
Diffusion is promoted by temperature differences on both sides of the material, in this case plastic, which separates the areas of high and low particle concentration. This is also referred to as ΔT (Delta T), the temperature difference in the area of high and low particle density. Positive or negative pressure also favours diffusion.
Time also plays a role. Thus, even low diffusion over a longer period of time leads to significant diffusion. A combination of diffusion risk factors can have an exponential effect on the overall probability of diffusion.
A dispersion, in the chemical sense, consists of two or more individual chemical components that do not or only partially combine with each other.
Dispersion in the narrower sense refers to the fine dispersion of polymers (in water). A character size of approx. 0.1 - 1 µm is referred to as finely dispersed, 1 - 10 µm as coarsely dispersed.
In surface technology, dispersion coating refers to those coating processes for which disperse coating materials (lacquers) are used (see dispersion). They can be cured by air drying or by adding temperature in an oven.
A thermoset coating refers to the coating with thermoset plastics.
Once the plastic has hardened, also known as cross-linked, it fulfils its function, e.g. as corrosion protection. Cross-linking can take place thermally or through the addition of a catalyser. The macromolecules are then tightly cross-linked and irreversible. They are plastically non-deformable, rigid, even when (further) temperature is added.
Origin
ECTFE was developed by the Solvay International Chemical Group and was first introduced to the market in 1970.
General information
Ethylene-Chloro-Tri-Flour-Ethylene - ECTFE for short - belongs to the group of fluorinated thermoplastics. ECTFE is better known under the trade name Halar®, a registered brand name of the Solvay company. ECTFE is a linear block copolymer. It is composed of ethylene and chlorotrifluoroethylene, which are the starting components in the form of molecular blocks linked to form chain segments.
Properties
ECTFE is characterised by high chemical resistance and dielectric strength.
- Usual processing temperatures: -75 °C to 150 °C
- Melting point: approx. 227 °C
- Application temperature: +140 °C
- Very low water absorption 4 x 10-2 %
- Coefficient of friction dyn dry: approx. 0.35 - 0.45
- Good resistance to UV and weathering
- Low permeation of corrosive gases
- Smooth with good non-stick coating
- Physiologically harmless
- Typical density: approx. 1.68 g/cm³
Chemical formula
Fields of application
ECTFE is a versatile engineering plastic. It is mainly used for corrosion protection coatings and electrical insulation. A typical application is the coating or lining in plant or pipe construction within the mechanical, electrical, semiconductor, nuclear, pharmaceutical and chemical industries.
Brand names
HALAR®ECTFE - Solvay Solexis SpA
Exothermic thermosetting plastics are cross-linked (baked) in the baking oven and achieve their chemical and mechanical properties in the process.
The term electrostatic coating refers to all electrostatic application processes. These are processes in which the sprayed coating material is attracted to the earthed workpiece under synchronised electrostatic charging (by means of high voltage or, in the case of triboelectric powder spraying systems, also by frictional electricity) and applied to it.
Epoxy resins (epoxy resins; abbreviation EP) are epoxy polymers
(organic compounds) with at least two epoxy groups per molecule that are used to produce thermosets. They are chemically very resistant and have extremely high adhesive strength.
Origin
ETFE was developed by the DuPont company back in the 1970s. This plastic was placed on the market under the trade name Tefzel®.
General information
Etylene tetrafluoroethylene - ETFE for short - belongs to the group of fluorinated thermoplastics from the polyhaloolefin family. The copolymer consists of tetrafluoroethylene and ethylene. ETFE is a further development of the widely used sintered material polytetrafluoroethylene - PTFE or Teflon®. As a partially fluorinated, semi-crystalline thermoplastic, ETFE combines the outstanding chemical properties of PTFE (Teflon®) with the mechanical and technical properties of polyethylene (PE). In contrast to Teflon® and perfluoroalkoxy (PFA), the plastic has a very low density and contains no plasticisers. It is processed by injection moulding and extrusion.
Properties
ETFE is characterised by high chemical resistance, light transmission and dielectric strength.
- Melting point: approx. 275 °C
- Application temperature: -100 °C to +150 °C
- Non-stick property
- Low water absorption
- Typical density: 1.67 - 1.75 g/cm3
Chemical formula
Areas of application
The plastic is also used for corrosion protection coatings and electrical insulation. A typical application is the translucent roofing and panelling of swimming pools, greenhouses and other buildings. The roofing of the Munich football stadium, the "Allianz Arena", is also made of the plastic ETFE. ETFE has proven to be particularly suitable for solar modules due to its weather resistance. The plastic is also suitable as a coating material for chemical equipment and containers.
Brand names
- DYNEON® ETFE - 3M / Dyneon
- FLUON® ETFE - Asahi Glass Co., Ltd.
- HOSTAFLON® ET - 3M / Dyneon
- TEFZEL® - DuPont
The Food and Drug Association (FDA; USA) inspects food, drugs and related devices for their safety.
FDA approval is regarded as a certificate for a safe product in the food industry.
Origin
FEP was developed by the DuPont company and was first introduced to the market around 1960.
General information
Fluoroethylene propylene - FEP for short - belongs to the group of perfluorinated fluorocarbon polymers. FEP is a semi-crystalline, thermoplastic co-polymer. It is composed of tetrafluoroethylene and hexafluoropropylene. FEP combines the chemical properties of PTFE (Teflon®) with those of PFA (perfluoroalkoxy). In contrast to Teflon®, FEP can be processed by injection moulding or extrusion.
Properties
FEP is characterised by the widest thermal working range of all fluorocarbon polymers to date as well as good anti-adhesiveness; it is water-repellent (hydrophobic).
- Plasticiser-free
- Physiologically harmless
- Non-flammable, but decomposes at high temperatures
- Resistant to radiation and weathering
- High chemical stability
- Usual processing temperatures: approx. 350 °C
- Melting point: approx. 282 °C
- Application temperature: - 250 to +205 °C
- Typical density: approx. 2.1 - 2.3 g/cm³
Chemical formula
Areas of application
A typical application is the production of transparent tubing materials. The plastic is used in the pharmaceutical and food industries as well as in medical technology. FEP is a versatile engineering plastic.
Brand names
- DYNEON® FEP - Dyneon / 3 M
- HOSTAFLON® FEP - Hoechst AG
- NEOFLON® FEP - Daikin Industries, Ltd.
- SYMALIT® FEP - Quadrant Group
- TEFLON® FEP - DuPont
Fluon® is a brand name of Asahi Glass Co. for various fluoroplastics.
The addition to the brand name indicates the abbreviation of the fluoroplastic.
Fluon® ETFE
Fluon® PTFE
Fluon® PFA
Fluon® FEP
A fluoroplastic coating is based on the use of fluorinated plastics such as PTFE, FEP, PFA, ETFE, PVDF, ECTFE.
The plastics are characterised above all by good chemical resistance and anti-adhesiveness.
In glass bead blasting, glass particles are blasted onto the workpiece using air pressure and the substrate is slightly roughened due to the abrasive effect of the glass. This gives the surface a matt or satin finish.
The abrasive effect can also remove light surface impurities. In the case of stainless steel, such surface impurities can be temper colours, for example, which occur after welding or thermal coating processes.
Anti-friction coatings reduce the friction between two surfaces.
The friction reduction factor is specified as a coefficient of friction.
There are a variety of coating materials for metal substrates, e.g. PTFE, PTFE with graphite and MoS2.
Greblon is a brand name of the Weilburger Coatings company for various non-stick and decorative coatings.
Halar® is a brand name of the company Solvay Solexis for products based on the plastic ECTFE.
Ilaflon® is a brand name of the company ILAG (Switzerland) for fluorine-bonded polymers, fluorine-containing coating plastics.
Corrosion protection is intended to prevent corrosion for the service life of a workpiece.
Corrosion is a reaction of a material to environmental media. Corrosion of iron is generally known as rust. Particularly aggressive media, such as acids and alkalis, can cause rapid corrosion in low-grade steels. An anti-corrosion coating counteracts this. It can be applied to various materials; many plastics also have a high chemical resistance.
Corundum is aluminium oxide or aluminium hydroxide (Al203) with a high hardness (Mohs hardness 9).
It has various applications in modifications, e.g. in coating technology as a blasting material for cleaning surfaces.
Molykote® is a brand name of Dow Corning for products containing MoS2.
General information
Molybdenum disulphide (MoS2) refers to the sulphide of the chemical element molybdenum.
Molybdenum and sulphur particles form a layered structure that is very lubricious. It is often used to optimise sliding, for emergency running properties or permanent sliding improvement. In coating technology, molybdenum disulphide is a component of a wide variety of anti-friction coatings.
Properties
Molybdenum and sulphur particles form a layer-like structure that is very lubricious.
- Temperature resistance
- Melting point: 1750 °C
- Typical density: 5.06 g-cm-3
- Solubility: Practically insoluble in water
Areas of application
MoS2 is often used to optimise sliding, for emergency running properties or permanent sliding improvement. In coating technology, molybdenum disulphide is a component of a wide variety of anti-friction coatings.
- Dry lubrication
- Admixture of various lubricating oils, improvement of sliding properties: longer service life of machine components
- As enriched greases: use in components
- Use in forming processes
Nanotechnology is a generic term for various technologies whose most important feature is the particle size, from a single atom to 100 nanometres (nm).
Products with nanotechnology have been in use for several decades, including in the field of coatings: as non-stick coatings (lotus effect) or as corrosion protection.
The miniaturisation of particles offers a wide range of possible applications, including in the semiconductor industry and pharmaceuticals, and is being further developed accordingly.
Neoflon® is a brand name of Daikin Industries (Japan) for fluorine-containing plastics, e.g. PFA.
Origin
Polyamide 11 - PA 11 for short - is a unique high-performance bio-based polyamide made from renewable castor oil seeds.
General information
PA11 is one of various types of polyamide that used to be summarised under the collective term nylon. The code number, in this case 11, indicates the number of carbon atoms between two secondary amide groups in the molecule. PA 11 offers an exceptionally high degree of versatility, safety and durability for a wide range of highly technical applications.
Special features
- Smooth surface
- Good sliding properties
- High elasticity
- High corrosion protection
- High insulating value
- High wear resistance
Properties
PA11 is a thermoplastic that is characterised by its particularly good chemical resistance, e.g. to acids and alkalis, and high elasticity.
- Fabric-friendly
- Physiologically harmless
- Good chemical resistance
- Sterilisable
- Good chemical, mechanical and heat resistance
- Melting point: +178 to +184 °C
- Operating temperature: - 55 to +100 °C
- Typical density: 1.04 g / cm3
Chemical formula
Areas of application
Due to its sterilisability, PA-11 is often used in medical technology.
Other areas of application for PA-11 coatings include
Hose and pipe materials in hydraulic brake systems, springs, pump housings, gearbox housings, washing machines and dishwashers, vehicle construction
(cardan shafts), Dragée boilers, dosing systems, tools, fittings, filter plates, sludge treatment and waste water systems, wire and mesh industry, stamped parts, sports equipment, fittings, internal and external pipework, containers, rotary valves, and many more.
Brand names
RILSAN® PA11 - Arkema Group
Origin
PEEK was developed in the laboratories of Imperial Chemical Industries and was first introduced to the market in 1979.
General information
Polyether ether ketone - PEEK for short - belongs to the group of thermoplastics. It is a semi-crystalline plastic.
Properties
PEEK is a harmless plastic. It is characterised by its resistance to most organic and inorganic chemicals and its high electrical insulation properties.
- High mechanical strength and rigidity
- High electrical insulation properties
- Excellent sliding properties
- Melting point: 335 °C
- Operating temperature: - 60 to +300 °C
- Typical density:
Chemical formula
Areas of application
PEEK is primarily used as a coating material for high-quality industrial products. PEEK is ideal for mechanical engineering, automation technology and general chemical laboratory and apparatus construction.
Brand names
- GATONE® - Gharda Chemicals Ltd.
- KADEL® - Solvay Advanced Polymers
- KETASPIRE®- Solvay Advanced Polymers
- KETRON® - Quadrant Group
- SUSTAPEEK® - Röchling Ingeneerig Plastics
- VESTAKEEP® - Evonic Industries AG
- VICTREX® - Victrex Manufacturing Ltd.
Origin
PFA was developed by the DuPont company and was first introduced to the market in 1972.
General information
Perfluoroalkoxy - PFA for short - belongs to the group of fluorinated thermoplastics. The copolymer consists of tetrafluoroethylene and perfluoroalkoxy vinyl ethers.
PFA is a further development of the widely used sintered material polytetrafluoroethylene - PTFE or Teflon®. As a perfluorinated, semi-crystalline thermoplastic, PFA combines the outstanding chemical properties of PTFE (Teflon®) with the mechanical and technical properties of polyfluoroethylene propylene (FEP). In contrast to Teflon®, PFA can be processed thermoplastically (injection moulding, pressing, extrusion, welding).
Properties
PFA is characterised by high resistance to almost all chemicals, a low coefficient of friction, high anti-adhesiveness and predominantly inert behaviour. PFA has low strength and hardness.
The melting point is approx. 310°C. It can be used at operating temperatures up to 260°C
- Usual processing temperatures: 380 °C to 450 °C
- Melting point: approx. 310 °C
- Operating temperature: -200 °C to +260 °C
- Coefficient of friction dyn dry: approx. 0.20-0.30
- Pronounced anti-adhesive behaviour
- Low water absorption (<0.03 %)
- Low thermal conductivity
- Typical density: approx. 2.15 g/cm³
Chemical formula
Areas of application
A typical application is the coating or lining of equipment in the chemical industry if the steel material has insufficient chemical resistance.
Brand names
Well-known brand names for PFA are
- NEOFLON® PFA - Daikin Industries
- SYMALIT® PFA - Daikin Industries
- TEFLON® PFA - DuPont
- DYNEON® PFA - Dyneon / 3M
- HOSTAFLON® PFA - Dyneon / 3M
- HYFLON® PFA - Solvay Plastics
PFA Ruby-Red® is a brand name of DuPont for a plastic coating material based on PFA, colour ruby red.
It stands out from other PFA coating materials due to its higher diffusion resistance and thus higher chemical resistance.
Phenolic resin is formed by chemically combining phenol with aldehydes. At temperatures above 150°C, this hardens and a plastic belonging to the group of thermosets is formed.
The main characteristics include electrical insulation properties and chemical resistance to most chemicals (except strong acids and alkalis).
Phenolic resins are used, for example, as a binder for chipboard, as a thermal insulator or as a coating, e.g. for containers, in the chemical industry.
The condensation of dihydric or polyhydric alcohols (e.g. glycol) produces polyester resin. They can be further processed into soft and hard polyester products.
Polyester resins are characterised, among other things, by good chemical resistance to weak acids, petrol and oils as well as good electrical insulation properties.
They are used in the production of laminate flooring, kitchen worktops, fillers, lacquers, etc.
Proco - EMAIL® is a brand name of HÜNI + CO (Friedrichshafen, Germany).
The coating process is based on a thermosetting plastic coating based on phenolic resin. It is characterised by high resistance to chemicals, especially acids, chlorinated products and solvents.
Proco - Plastic Coatings® is a brand name of HÜNI + CO (Friedrichshafen, Germany) for various plastic coatings, which are mostly used for corrosion protection, non-stick or sliding optimisation or electrical insulation.
The name Proco, in conjunction with the plastic used, gives its name to many of the company's coating processes, e.g. Proco - PFA, Proco - PTFE, Proco - E-CTFE (Halar®), Proco - PA 11 (Rilsan®).
Origin
PTFE was developed on the basis of fluorocarbons by DuPont, which was given the trade name TEFLON®. DuPont received the US patent for this polymer in 1941.
General information
Polytetrafluoroethylene - PTFE for short - is a polymer consisting of fluorine and carbon. Products made of PTFE are characterised by high chemical resistance. The term "PTFE coating" is therefore often used as a substitute for "fluoroplastic coatings for corrosion protection".
Properties
PTFE is hardly wettable and very anti-adhesive. The coefficients of friction, static and dynamic, are very good compared to all solids, as is the resistance to corrosion and solvents. Products made of PTFE are characterised by high chemical resistance.
- Hydrophobic
- Melting point: +327 °C
- Operating temperature: -200 °C to 260 °C
- Typical density: 2.16 g / cm3
Chemical formula
Areas of application
The plastic is often used as a non-stick coating or sliding coating. PTFE is used in electrical engineering due to its excellent insulating properties. Due to its UV resistance, the plastic is also ideal for outdoor constructions. TEFLON® offers corrosion protection and non-stick properties as a coating material on metal surfaces. Teflon tubing materials are also of very good quality, which is why they have become indispensable in biology, chemistry and technology laboratories.
Brand names
- ALGOFLON® PTFE - Solvay Plastics
- DYNEON® PTFE - 3M / Dyneon
- FLUON® PTFE - Asai Glass Co., Ltd.
- HALON® PTFE - Allied Chemical Corp.
- HOSTAFLON® - 3M / Dyneon
- POLYFLON® - Daikin Industries Inc.
- TEFLON® - DuPont
Powder coating is a coating process in which the coating material is applied in powder form and then melted or baked on.
The most common form of powder coating is done with epoxy and polyester resins, which are cross-linked at 130 - 200°C. This process has replaced many wet coatings in a wide range of industries. It is a solvent-free process and has replaced many wet coatings in a wide range of industries. The terms powder coating and powder coating are therefore often used synonymously.
Pyrolysis Text
Pyrolysis is a pyrolytic decomposition. In a thermal process, without the addition of oxygen, chemical compounds are broken down; large molecules are converted into small molecules.
Pyrolysis is also colloquially known as burning or incineration. In the case of plastics, the matrix is destroyed and they disintegrate.
In coating technology, pyrolysis is an upstream process when workpieces with an old coating are refurbished, i.e. recoated.
Rilsan® is the brand name for polyamide 11 from Arkema®.
In sandblasting, sand is blasted onto a surface using compressed air and its surface properties, usually abrasive, are changed, for example rust is removed.
The effect of various abrasive blasting media, such as sand, steel shot or corundum, cleans the surface, makes it larger and creates a textured surface. This is used for paintwork and coatings so that the paint can adhere better to the surface and substrate adhesion can be optimised.
Blasting is not only carried out with sand (granular sedimentary rock) to achieve various surface effects. Typical blasting media include corundum, glass beads, nutshells, plastic and dry ice.
Sintered coatings are those in which the workpiece is first heated, a plastic is sprayed on or immersed in it (immersion sintering) and melted by the heat contained in the workpiece.
The shaping heating of a material (with subsequent cooling) is referred to as sintering.
If sintering takes place in a mould or workpiece, the material fills the mould completely or in a (thin) layer and thus takes on its shape.
If sintering takes place on a mould, the material, together with its shape, forms its contours. Typical sintering processes with plastics in this category include dip sintering. In this process, the heated mould is briefly immersed in a powdered and fluidised plastic. Another typical sintering process is the electrostatic application of the plastic to the hot mould.
In the sintering furnace, moulds or workpieces are heated in order to be sintered with a plastic (see sintering).
Teflon® is a brand name of Du Pont de Nemours and includes various fluoroplastics.
In common parlance, Teflon® refers to a non-stick coating with PTFE, such as is widely used in frying pans or baking tins.
The brand name Teflon® also includes Du Pont products made of FEP, PFA, ETFE and PVDF. In industrial coatings, a Teflon® coating therefore stands for non-stick coating, anti-friction coating and anti-corrosion coating.
Teflonising or Teflon is primarily understood to mean coating with fluorine-containing plastics such as PTFE (polytetrafluoroethylene) to prevent or minimise adhesion (sticking).
In the consumer sector, non-stick coatings with Teflon® on frying pans and baking tins are colloquially anchored and have coined the term Teflonising.
In the extended interpretation of the term, Teflonising includes non-stick coatings, anti-friction coatings and also corrosion protection coatings. In addition to materials such as PTFE, this also includes plastics such as ECTFE, ETFE or FEP.
A grease-free surface is an essential condition for the substrate adhesion of coatings and other surface finishes. In addition to chemical degreasing, thermal degreasing is also used for this purpose.
At high heat, substances such as oils and greases burn during thermal degreasing. The residues produced during the process would reduce the substrate adhesion of a coating and are therefore removed, e.g. by radiation.
In thermoplastic coating, thermoplastics are used as the coating material. These liquefy when heated and solidify again when the temperature drops. Thread-like, thermolabile macromolecules make this process reversible and repeatable.
Thermoplastics include PA, PE, ETFE, ECTFE, PFA, PVDF and PVC.
A typical coating process is, for example, fluidised bed sintering.
A plastic powder in a container is fluidised from below through a sieve and the powder is gently whirled up. Workpieces (made of metal) preheated to 200 - 400°C are immersed. The plastic is sintered and melts onto the workpiece.
For workpieces with different wall thicknesses, the powder that is not completely sintered in the first process is remelted in a furnace by adding an external temperature. Both processes together are also known as the double-heating process.
Xylan® is a brand name of the company Whitford, USA for its fluoropolymer coating materials with the main plastics PTFE, PFA and FEP.
The coating materials are formulated for various non-stick and anti-friction coatings.
Additional functions such as (conditional) corrosion protection, approval for contact with food, service life optimisation (EXCALIBUR, TITANIUM, etc.) offer individual optimisation options.
Xylan® Company Whitford, USA http://www.whitfordww.com/industrial/xylan.html