Gluing plastic: Which adhesive will stick to which type of plastic?
Not every adhesive will stick to every plastic. While ABS and PVC are straightforward, PE, PP, and PTFE are notoriously difficult to bond to. This guide explains why, which adhesive technology is suitable for which plastic, and how to reliably achieve adhesion through pretreatment and primer.
Why some plastics are difficult to glue
Surface energy is crucial . An adhesive will only wet a material effectively if the material's surface energy is higher than that of the adhesive. Plastics with low surface energy (LSE) – typically below around 36 mN/m – practically repel the adhesive.
- Good adhesion (high surface energy): ABS, PC, PVC, PMMA, PA, PET.
- Difficult (LSE): PE, PP (polyolefins) and especially PTFE (“Teflon”).
For difficult plastics, adhesive alone is usually not enough – pretreatment, primers or specially formulated systems are needed.
Plastics from simple to complex – an overview
| plastic | Adhesive properties | Proven adhesives | Notice |
|---|---|---|---|
| ABS, PC, PVC, PMMA | good | Cyanoacrylate, 2-component epoxy, UV, solvent-based adhesive | usually without pretreatment |
| PA (Polyamide), PET | medium | 2K epoxy, 2K acrylate, cyanoacrylate | Clean, sand if necessary |
| PE, PP (polyolefins) | difficult (LSE) | 2K acrylate (MMA), cyanoacrylate with polyolefin primer | Primer or pretreatment required |
| PTFE, silicone | very difficult | only with special pretreatment / primer | chemical/physical activation |
Guideline values – the specific suitability depends on the product and application and should be checked in the technical data sheet.
Adhesive technologies in brief
Cyanoacrylate (superglue)
Fast, clean, ideal for small joining surfaces and many plastics. Cyanoacrylates with polyolefin primer are available for PE/PP .
2K acrylate / MMA
Structurally high strength and particularly strong on difficult plastics – often the first choice for PE/PP without complex pretreatment.
2K epoxy
High strength and chemical resistance on readily bondable plastics and metals – however unsuitable for PE/PP/PTFE.
Polyurethane & MS polymer
Elastic, suitable for different material pairings, gap bridging and dynamic loading.
UV-curing adhesives
Cures in seconds at the touch of a button, ideal for transparent plastics and visible bonding.
The difficult cases: PE, PP, PTFE
Three paths lead to a durable connection:
- Special adhesive: 2K acrylate for LSE plastics or cyanoacrylate in a set with polyolefin primer.
- Primer/adhesion promoter: increases surface energy and thus wetting.
- Physical pretreatment: sanding, flame treatment, corona or plasma.
Surface preparation – the underestimated lever
Even the best adhesive choice can fail due to a poor surface. The proven sequence is: clean and degrease (e.g., with isopropanol) → roughen → primer → bond. Clean, well-defined surfaces are half the battle.
Common mistakes
- Epoxy on PE/PP is expected – it practically does not adhere.
- Grease or release agent residue on the surface.
- Incorrect gap filling: thin superglue used for a large gap.
- No adhesion test on the original substrate prior to series production.
Find the right adhesive in 4 steps
- 1. Determine the material: Which type of plastic (if applicable, recycling code)?
- 2. Clarify the load: strength, temperature, media, flexibility.
- 3. Choose technology: according to the table above.
- 4. Test on the original part: including pretreatment, then check the data sheet.
Sources and technical basis
The information is based on manufacturer data sheets (including Permabond, Henkel/Loctite) and generally accepted adhesive bonding principles. The specific suitability for a particular product and substrate depends on the product and can be found in the respective technical data sheet; an adhesion test on the original part is recommended.
How SILITECH supports
Tell us the type of plastic, the load, and the quantity – we will test suitable adhesives and primers and provide the corresponding technical data sheets.
