Appliance Coatings

On an appliance the finish is the visible product, so this range is organised by position on the machine rather than by chemistry. It covers the sheet steel, galvanised steel, aluminium and moulded parts that make up refrigerators, washing machines, air conditioners, ovens and small appliances: the cabinet, door, lid and casing on the outside, and outer tubs and tub fittings, inner panels, chassis, brackets, handles and control panels behind them. Exposure differs by position. An exterior panel faces handling, kitchen and laundry cleaning agents, humidity and years of visible service, while a part inside a wet appliance faces hot water, detergent and condensate. Not every interior surface is coated at all: washing machine drums are normally stainless steel, refrigerator inner liners are normally thermoformed plastic, and a cooking oven cavity is normally vitreous enamel or a proprietary pyrolytic system rather than an organic paint, so interior work is quoted part by part against the substrate and the exposure actually present. Automotive Coatings shares the substrate and the stoving process with this range, and the separation is end use and service life: an appliance lives indoors, is judged at arm’s length under showroom light, and is expected to hold that appearance through years of wiping and handling, not through weathering, road salt, stone strike and a refinish chain. Where an appliance panel is powder coated, the powder itself is described under Powder Coatings, and this range states what the appliance asks of it.

Appearance is the defining constraint. A single machine is assembled from panels that may be coated on different lines, in different batches, or bought in already painted, and colour and gloss have to match across all of them under showroom lighting, which puts batch-to-batch repeatability and a tight tolerance against a master standard ahead of most other properties. The second constraint applies to coated sheet that is formed after painting: a film applied flat and then roll-formed, bent or drawn has to stretch with the metal instead of cracking at the bend radius, which calls for a more flexible resin system than a panel painted after forming needs, so each product is specified for one route or the other and the datasheet says which. Chemistry then follows position and exposure. Appliance powders are thermosetting, meaning resin and cross-linker react in the oven, the cured film cannot be re-melted, and application is by electrostatic spray onto an earthed part. Thermoplastic powders are a separate family: they melt and solidify without reacting, are usually applied by fluidised bed dip onto a preheated part, and suit thick, tough coverage such as coated wire goods rather than a visible flat panel. Within thermosetting powder the conventional positions are well established. Epoxy is used where chemical resistance matters and daylight does not reach the part, epoxy-polyester hybrid is the usual indoor white goods panel finish, and polyester is the exterior grade, because an epoxy film chalks and loses gloss under ultraviolet. An air conditioner outdoor unit is specified as an exterior polyester for that reason, even though it belongs to the same product as indoor panels that can be hybrid.

Each route decides what the plant must have. Powder finishing needs a pretreatment line, clean, rinse, conversion coating and dry off, then an earthed conveyor and hanging system, clean dry compressed air, an electrostatic spray booth with powder recovery, and a cure oven, because thermosetting powder is conventionally stoved at metal temperatures around 180 °C, with the exact schedule set by the powder in use. There is no solvent to flash off, but the oven capacity, the extraction and the earthing are not optional, and a part that never reaches metal temperature never cures, whatever the air temperature in the oven reads. Liquid stoving finishes need spray or flow application, a flash off zone, solvent rated extraction and a stoving oven. Pre-coated sheet is not applied in the appliance plant at all: it is applied by a coil coater on a roller coating line with a high-velocity curing oven, so the appliance maker buys painted coil and carries out forming and assembly only. Appliance finishing is a new capability area for Arctic Materials, with grades described against the panel, the substrate and the line that will run them, and a Technical Data Sheet and a Safety Data Sheet issued for each. None of these coatings is offered for direct food contact.

Visible panel finishes for refrigerator cabinets and doors, washing machine lids and front panels, air conditioner casings and dishwasher fronts. These grades carry the appearance of the machine, so they are specified against a retained master standard for colour and gloss and are held to a batch tolerance agreed in writing before supply. The subfamily separates indoor panels, which are conventionally epoxy-polyester hybrid, from outdoor-facing units, which need a saturated polyester resin because an epoxy or hybrid film chalks and loses gloss under ultraviolet.

Coatings for the metal behind the visible panel: chassis, base frames, brackets, back and inner panels, outer tubs, tub fittings and condensate trays. Exposure here is chemical and thermal rather than visual, so the grades are written against hot water, detergent, bleach and condensate, and against handling damage on the assembly line. Parts that are stainless steel, moulded plastic or vitreous enamelled are not coated at all, so interior work is quoted part by part against the substrate and the exposure actually present.

Silicone and silicone-polyester finishes for oven outer doors, hob surrounds, grill and burner housings, warming drawer fronts, flue trims and heater panels, where the film sees repeated heating and cooling rather than one bake. Grade selection follows continuous service temperature and whether the part has to hold a colour or only has to survive, since above about 300 degrees C only inorganic pigments and metal flake remain stable. The cooking cavity itself is conventionally vitreous enamel or a proprietary pyrolytic system and sits outside an organic coatings range.

Low surface energy topcoats for the surfaces a user touches every day: handles, door fronts, control panels and fascia trims. The function offered is soil release and reduced fingerprint visibility on wiping, assessed as cleanability and stain resistance on panels in the customer’s own colour and texture. Where an antimicrobial additive is requested it is supplied with the additive manufacturer’s own regulatory documentation, and any antibacterial, hygienic or biocidal statement printed on the finished appliance is a regulated claim made by the appliance manufacturer for the market of sale. Arctic makes no efficacy claim.

Liquid finishes for kettles, mixers, food processors, fans, extractor hoods, air purifiers and similar housings, where the part is small, often moulded, and frequently cannot take a stoving schedule. Cure temperature is the governing constraint, so these grades are written for low bake and force dry lines and for mixed metal and plastic assemblies that must match across both substrates. Hardness and mar resistance are weighted heavily because the surface is handled daily.

Repair and edge coatings for parts made from pre-coated coil, where the paint was applied by a coil coater on a roller coating line and the appliance plant carries out forming and assembly only. The grade is matched to a retained sample of the coil in use and is applied to sheared edges, drilled holes, fixing points and handling damage. It is a repair material, not a substitute for a designed edge or a fold that hides the cut metal.

The figures below are the typical operating window for this range, not a measured result for any one batch. Confirmed values are issued with the Technical Data Sheet and Certificate of Analysis by our laboratory.

Grade codes in this range follow one rule: the subfamily code, then a three digit number that rises with performance and film build inside that subfamily. The leading digit is the tier, so Arcdom EX 320 sits above Arcdom EX 210 on weathering and film build, and Arcdom HT 320 sits above Arcdom HT 210 on service temperature. Not every subfamily uses every tier, and Arcdom AB 310 and Arcdom PC 210 are the only grades in theirs, so a tier number carries meaning only inside its own subfamily. A higher number is never a claim of superiority over another subfamily, because the subfamilies answer different exposures.

Pretreatment sets the ceiling for everything that follows. The line needs clean, rinse, conversion coating and a dry off that removes water from seams and blind holes, and the conversion coating weight is agreed before the finish is specified, because the adhesion, humidity and salt spray windows in the table above are only reachable on a correctly pretreated surface. Drawing compound, press oil and weld spatter left on the part are the usual cause of craters and edge failures, and no coating in this range corrects them.

Powder grades are applied by electrostatic spray onto an earthed part, with clean dry compressed air, a booth with powder recovery and a cure oven. The control point is metal temperature, not oven air temperature: a thick bracket and a thin door skin on the same hanger reach temperature at different times, so the schedule is set by the slowest part on the jig and confirmed with a data logger on a representative body. Liquid stoving grades need a flash off zone long enough to release solvent before the part enters the oven, solvent rated extraction, and the same metal temperature discipline. Small appliance grades are the exception: their limit is the highest temperature the moulding will take without distortion, which is why they are written for force dry rather than stoving.

Cure is verified, not assumed, because an undercured film passes a visual inspection and fails in service. For liquid stoving and two component grades a solvent double rub gives a quick line check, and for powder grades the record is the logged metal temperature and dwell on a representative body, since a solvent rub does not discriminate cure on a crosslinked powder film. Hanger position, jig density and line speed are recorded with the result, because the same oven gives a different answer on a full jig. Two component grades are mixed at the stated ratio and discarded at the end of pot life, and a film that has only been force dried is not yet at final hardness when it reaches assembly.

Colour control across a panel set is the property most often judged by the customer, and it is a line discipline as much as a paint property. Each batch is measured against a retained master panel rather than against the last batch delivered, because measuring against the previous batch lets the colour drift one step at a time until the door no longer matches the cabinet. The measuring geometry, the illuminant and the tolerance are fixed in writing at specification, panels from different lines are compared in a light booth under that illuminant with a second illuminant used to check metamerism, and film build is held inside its window, since a thin film over a different primer or a different substrate will read as a colour difference even when the paint is identical.

The forming route decides the resin system. A part painted after forming can use a harder, higher gloss film, while a part formed after painting has to stretch with the metal at the bend radius, which is why pre-coated sheet is a coil coater product and Arcdom PC 210 exists only to repair it. Sheared edges and severe radii leave metal exposed and are answered in the design of the part, by folding the cut edge away or hiding it in the joint, not by adding paint. High-temperature grades need their post-cure planned into the build, because a silicone film that has only been force dried is not yet at its final hardness, and the first heat cycle of the assembled appliance will release light smoke and odour.

A Technical Data Sheet and a Safety Data Sheet are issued for every grade, with the cure schedule, the film build window, the recoat window and the test methods used. A compliance dossier for a specific market, including the regulatory documentation held for any additive, is issued on request. None of the coatings in this range is offered for direct contact with food or with potable water, and Arctic makes no antibacterial, hygienic or biocidal efficacy claim for any grade in it.

Specifying an appliance finish correctly needs answers to the following, and Arctic will not recommend a grade code without them. Sample panels in the customer’s own colour and on the customer’s own substrate are the last step, not the first.

• Which part, and where does it sit on the machine? Name the part, not the appliance: a cabinet side, a washing machine outer tub and an oven door trim are three different grades on one product.
• What is the substrate, and what pretreatment is available? Cold rolled, galvanised or pre-galvanised steel, aluminium, zinc die casting, stainless, or a moulding, and the conversion coating and dry off the line can actually run.
• Is the part painted before or after forming? If after painting, state the tightest bend radius, the draw depth and whether cut edges remain exposed in the finished assembly.
• Indoor or outdoor exposure? An air conditioner outdoor unit needs a saturated polyester exterior grade even when the indoor panels of the same product can be hybrid.
• What can the oven do? Type of oven, achievable metal temperature, dwell time at temperature, line speed, and the heaviest and lightest part that will share a jig.
• What is the appearance specification? Colour, gloss level and the geometry it is read at, texture or smooth, the master standard to be held against, and the batch tolerance to be written into the supply agreement.
• Which panels have to match each other? List the parts of one machine that are coated on different lines, in different materials or bought in already painted, because that set defines the tolerance, not the individual panel.
• What will be used to clean it in service? Name the cleaning agents and the staining agents to be included in the spot test, and how many wipe cycles the surface is expected to take over its life.
• What temperature does the part reach, and for how long? For oven and hob parts give continuous service temperature, peak temperature, and the number of heating and cooling cycles expected, since cycling, not the peak, is what fails a film.
• What wet exposure does the interior part see? Water temperature, detergent type and concentration, bleach exposure, and whether the surface stands wet or drains.
• Will any hygiene or antibacterial statement be printed on the appliance, and in which market? That claim is made by the appliance manufacturer under the regulations of the country of sale, so the wording and the market are confirmed before an Arcdom AB grade is specified.
• Is any coated surface in direct contact with food or potable water? If so, the part is outside this range and is specified separately.
• What application equipment is in place? Electrostatic powder, air assisted or airless liquid spray, HVLP, dip or flow coat, and for two component grades whether the plant mixes by hand or by proportioner.
• How is cure recorded? Whether the line has a data logger for metal temperature, who signs off the record, and what happens to a jig that misses the schedule.
• How is the part handled after cure? Cool down before stacking, interleaving or protective film, rack contact points, and the transit route, since most damage found at the customer is handling damage rather than coating failure.
• For pre-coated parts, who supplies the coil? Provide a retained sample of the coil in use and its topcoat type, since a touch-up grade is matched to that sample and not to a colour number.
• What repair route is expected? State whether repairs are made in the plant, in the field or both, the maximum repair area acceptable, and who judges the repaired area against the retained sample.

The Technical Data Sheet, Safety Data Sheet and regulatory declaration for any grade in this range are issued by our laboratory against the substrate and process you are running. Tell us the job and we will specify against it.