Thermoplastic Adhesives


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.


Type Notes
Materials 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).
Materials Bonded ...:Wood, Metal, glass, ceramics,
Acrylic solvent cement. (flexible) Polymethyl methacrylate (PMMA) dissolved in methyl chloride. High tack strengths relatively lower bond strengths.
Materials Bonded ...:Paper Aluminium, Metals, Textiles, Brick/concrete/ceramic, Rubber, PF, Polyester, LDPE/HDPE, Polystyrene, ABS, Polycarbonate, PVC Acrylic, Amides(nylon), Cellulose Acetate,
Toughened Acrylic(Structural) Toughened 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.
Materials Bonded ...:Aluminium, Metals,Glass, Brick/concrete/ceramic, Rubber, PF, Polyester,LDPE/HDPE, Polystyrene, ABS, Polycarbonate, PVC Acrylic, Amides(nylon), Cellulose Acetate, PTFE etc, Acetal, very good for metals.
Toughened Acrylic
Flexon .
As above but single part - Requires 24 hours for full strength. But good wet tack allowing rapid assembly.
Materials Bonded ...:Most materials , Aluminium, Metals,Glass, Brick/concrete/ceramic, Rubber, PF, Polyester, LDPE/HDPE, Polystyrene, ABS, Polycarbonate, PVC Acrylic, Amides(nylon), Cellulose Acetate, PTFE etc, Acetal, very good for metals..
Cyanoacrylates Harden quickly in seconds based on catalytic action of surface moisture. Good for rubber. Care needed when used with metals in moist warm conditions. Typical Trade Name "Superglue".
Materials Bonded ...:Aluminium, Metals, Textiles,Glass, Brick/concrete/ceramic, Rubber, PF, Polyester, LDPE/HDPE, Polystyrene, ABS, Polycarbonate, PVC Acrylic, Amides(nylon), Cellulose Acetate, Polyurethane, PTFE etc, Acetal
Silicone resins Two part thixotropic adhesive provides electrical insulating properties. Low strength but high working temperatures.
Materials Bonded ...:Aluminium, Metals, Glass, Brick/concrete/ceramic, Rubber, Polyester, LDPE/HDPE, PVC, Acrylic, Amides(nylon), Cellulose Acetate, Polyurethane, PTFE etc, Acetal
Polyamines (Nylon) Applied hot and set on cooling. Same properties as nylon.
Materials Bonded ...:Wood, wood exterier,Paper, Aluminium, Metals, Textiles, Brick/concrete/ceramic, UF etc, Epoxy, Polyester, ABS, Polycarbonate, PVC, Amides(nylon)
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. Typical Trade Name "Loctite" Used to lock , seal, retain all types of turned threaded, fitted parts.
Materials Bonded ...:Metals,.


Sites Providing Relevant Information
  1. Adhesives Toolkit..The Adhesives Design Toolkit - Very very useful information source
  2. Polyimides as Adhesives: -Literature review..Interesting Article -Provides useful notes on adhesive science
  3. Design Bites.. Download booklet "Joining technique" Including section on Adhesives -very good value for �5