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Thermoplastic Adhesives

Thermoplastic adhesives are fusible, soluble and poor heat and creep resistant. They are normally used for low/medium load assemblies under reasonable service conditions In general, thermoplastic adhesives have low/medium shear strength and suffer from creep at high loading. They have good resistance to oils but poor resistance to water. Thermoplastic adhesives include polyvinyl acetate (PVA), polyvinyl alcohol (PVA), polyacrylates, polyester acrylics, acrylic solvent cement, cyanoacrylates (superglue), silicone resins, polyamides and acrylic acid diesters.

Over the last 35 years, properties of thermoplastic adhesives have been enhanced by toughening such that variants are available suitable for structural duties. There is widespread use of thermoplastic adhesives (anaerobic) adhesives for radial fit assemblies, and screw locking assemblies.


TypeNotesMaterials Bonded
Polyvinyl Acetate (PVA)Supplied as an emulsion in water, for porous materials, especially wood. Shear strength is good. Resistant to oil . Poor resistance to water. Low heat tolerance. ( White glue)Wood, Metal, glass, ceramics,
Acrylic solvent cementPolymethyl methacrylate (PMMA) dissolved in methyl chloride.PMMA,styrene,Polycarbonate, UPVC
Toughened AcrylicToughened acrylics( 2 part) are relatively fast curing and offer high strength and toughness, plus have more flexibility than common epoxies. They tolerate minimal surface preparation and bond well to a wide range of materials. High peel strength adhesive. Flexon variant single part -24 hours full strength.Most materials , very good for metals.
Toughened Acrylic
Flexon
As above bu single part - Requires 24 hours for full strength. But good wet tack allowing rapid assembly.Most materials , very good for metals.
CyanoacrylatesHarden quickly in seconds based on catalytic action of surface moisture. Good for rubber. Care needed when used with metals in moist warm conditions. "Superglue"Metal, ceramics, plastics etc.
Silicone resinsTwo part thixotropic adhesive provides electrical insulating properties. Low strength but high working temperaturesFluorocarbons
PolyaminesApplied hot and set on cooling. Same properties as nylon.Metal, wood, plastics , laminates
Anaerobic
Acrylic acid diesters
Sealant, locking compounds set in the presence of metals and the absence of atmospheric oxygen. In use this hardens when used in a completed assembly. Used to lock , seal, retain all types of turned threaded, fitted parts.,Metals,.