Technical Information dispelling traditions - Formica

formica_technical.qxd:formica_technical.qxd 28/11/08 16:01 Page 14Adhesives 1 of 2Urea/Melamine UreaResorcinolEpoxyDescriptionRigid thermosetting adhesives. Curing is by polymerization when the correct amount of catalyst is added to theresin. The rate of cure is rapidly increased by the application of heat.ApplicationUsed in flat lamination, hot or coldpressed to bond laminates to mostwood based substrates.Melamine/Urea is useful forbonding to moisture resistantcore materials.Poor gap filling properties but givesa good bond at relatively lowpressures. Ureas are oftenextended by fillers which also helpto reduce telegraphing of coreimperfections. Cure time typically1 to 3 hours at room temperaturedepending on hardener system.Used in flat lamination, hot orcold pressed to bond laminatesto moisture resistant wood basedsubstrates, some flame retardantsubstrates and non-combustiblesubstratesGood gap filling properties.Satisfactory bonds are producedat low pressure. Cure time typically5-8 hours at room temperature.Used in flat lamination, hot orcold pressed to bond laminatesto metal substrates which havefirst been primed. Also useful forbonding laminates to aluminiumhoneycomb cores.Excellent gap filling properties.Requires only low pressure.Minimal telegraphing due to highsolids content (lack of shrinkage).Wide range of room temperaturecure times depending onhardener system.TypicalTemperatureResistance-20°C to +120°C.-20°C to +150°C.-20°C to +100°C.Typical EN 204Durability classD3 – D4D4D3 – D4Polyurethane (PU)Single & Part 2 SystemsDescriptionApplicationLaminationTelegraphingMoisture ResistanceSingle Part MCPU (Moisture Curing Polyurethane). Realise on water/moisture to set off the curing. Hot pressingaccelerates curing cycle. Must have one of the substrates porous. Two part P/U realise on mixing the resin andcatalyst together to set off curing cycle. Hot pressing accelerate curing cycle. Excellent for bonding together nonporous materials.Used in flat lamination. Hot or cold. Applied by hand or specialised automatic rollers (steel). Spray and handspreader/brush. One surface only.Excellent gap filling properties. Low, or high pressure vacuum or hydraulic pressing. Excellent for bonding todifficult substrates such as polystyrene, metal, GRP, plastics etc. As well as most timber based substrates tothemselves and/or to mixed combinations of facing laminates.Moderate telegraphing of core, dependent on method of bond consolidation and method of applying glueline.High humidity and frequent wetting. Very good D3 – D4 EN204 Durability. Frequent, short term exposure torunning water and exposure to extreme humid contitions.Not affected by high/low -20°C +120°CTemperature ResistanceVery good (deteriorate with use of keytone/acetone blends of solvents) EN438Chemical ResistanceHigh, special 1 part = D2 – D32 part = D3 – D4Bond StrengthRatingKey to EN 204 durability classes in adhesives table.D1 Interior areas, where the temperature only occasionally exceeds 50°C for a short time and the moisture contentof the wood is 15% maximum.D2 Interior areas, with occasional short term exposure to running or condensed water and/or to occasional high humidityprovided the moisture content of the wood does not exceed 18%.D3 Interior areas, with frequent short-term exposure to running or condensed water and/or to heavy exposure to high humidity.Exterior areas not exposed to weather.D4 Interior areas with frequent long-term exposure to running or condensed water.Exterior areas exposed to weather.13Formica Limited, Coast Road, North Shields, Tyne & Wear NE29 8RE. Tel: 0191 259 3000. Fax: 0191 258 2719.Formica is a registered trade mark of Formica Corporation or its subsidiaries.Technical Services Department May 2003.