PREP K

What it is and why choose it

Bostik PREP K is a transparent liquid pretreatment designed to enhance the adhesion of specific Bostik elastic bonding products based on Silyl Modified Polymer (SMP) and silicones on plastic substrates. It is easy to apply by brush or cloth and is particularly suitable for hard and soft PVC and ABS. By correctly pre-treating the surface, PREP K helps achieve a stronger, more reliable bond and improves long-term performance of the adhesive or sealant.

Main features

• Improved adhesion on compatible plastic substrates when used with selected Bostik SMP and silicone products.
• Easy application by brush or clean cloth, ideal for workshop and production environments.
• Suitable for several plastics including hard and soft PVC and ABS (not for PP, PE or PTFE).
• Transparent pretreatment; can become visible due to UV discolouration, which can be controlled with masking tape where needed.
• Fast drying: typical drying time about 30 minutes at 20°C and 50% relative humidity.
• Efficient coverage: approximately 4–6 m² per litre, depending on substrate and application method.
• Professional-grade formulation supplied in 500 ml tins for controlled, repeatable use.

Technical specifications

• Product type: Surface preparation agent / pretreatment for plastics
• Physical form: Low-viscosity liquid
• Colour: Transparent
• Dry content: 12 %
• Specific gravity: 0.9 g/ml
• Flash point: < 0°C
• Drying time (20°C / 50% R.H.): approximately 30 minutes
• Application temperature: +5°C to +30°C
• Covers: approximately 4–6 m² per litre
• Packaging: 500 ml tin
• Storage stability (unopened): up to 9 months in a dry place at +5°C to +30°C

Applications and use cases

Suitable substrates

• Hard PVC (rigid)
• Soft PVC (flexible)
• ABS

Do not use PREP K on PP, PE or PTFE.

Typical use cases

• Pre-treatment of PVC and ABS components before bonding with compatible Bostik SMP or silicone adhesives and sealants.
• Improving adhesion on plastic trims, profiles, panels and fittings in professional or industrial applications.

Method of use

1. Surface preparation: Ensure the substrate is dry, clean and free of grease and dust. Strongly contaminated surfaces should first be cleaned with Simson Cleaner 14 or Bostik Cleaner 1. Check that the cleaner does not affect the surface.
2. Handling the container: Keep the container closed until the moment of application. Open the container and puncture the foil.
3. Decanting: Do not use PREP K directly from the original container. Pour only as much product as can be used within 30 minutes into a separate clean metal or glass can. Do not return unused material to the original container. Do not use remains of product after 30 minutes.
4. Application: Apply PREP K with a clean brush or cloth in a thin, even layer on the substrate.
5. Masking (optional): PREP K is transparent but may discolour under UV light. If this is not desired, mask off the surrounding area before application.
6. Drying: Allow a minimum drying time of about 30 minutes at 20°C / 50% R.H. before applying the adhesive or sealant.
7. Bonding window: Achieve best results by bonding or sealing within 6 hours after applying PREP K.
8. Handling of treated surfaces: Do not touch the cleaned and pretreated surfaces and avoid condensation on the substrate, as this can reduce adhesion.

FAQ

• On which substrates can I use Bostik PREP K?

  PREP K is intended for hard and soft PVC and ABS. It is not suitable for PP, PE or PTFE.

• How long should PREP K dry before applying the adhesive?

  Allow a drying time of approximately 30 minutes at 20°C and 50% relative humidity before bonding or sealing.

• What is the ideal bonding window after pretreatment?

  For best adhesion, apply the Bostik adhesive or sealant within 6 hours after PREP K has been applied.

• What is the coverage of PREP K?

  Coverage is approximately 4–6 m² per litre, depending on substrate porosity and application method.

• How should I store PREP K?

  Store unopened tins in a dry place at temperatures between +5°C and +30°C. Under these conditions the product is stable for up to 9 months.

• Can I pour unused product back into the original container?

  No. Do not return unused product to the original container and do not use remains older than 30 minutes once decanted.

• Does PREP K change the appearance of the substrate?

  PREP K is transparent but may discolour under UV light, making the treated area visible. Use masking tape where this is undesirable.

• Can PREP K attack some plastics?

  Yes, PREP K may attack the surface of some plastics. Always carry out a compatibility test on the substrate before full-scale use.

• Is PREP K suitable for consumer use?

  Consultar ficha técnica del fabricante.

Section 14 – Transport information

• UN number (ADR/RID, IMDG, IATA): UN1993
• UN proper shipping name: Flammable liquid, n.o.s. (Methyl ethyl ketone, Xylenes)
• Transport hazard class: Class 3 (flammable liquids)
• Packing group: II
• ADR description: UN1993, Flammable liquid, n.o.s. (Methyl ethyl ketone, Xylenes), 3, II, (D/E)
• IMDG description: UN1993, Flammable liquid, n.o.s. (Methyl ethyl ketone, Xylenes), 3, II, (-9°C c.c.)
• IATA description: UN1993, Flammable liquid, n.o.s. (Methyl ethyl ketone, Xylenes), 3, II
• Environmental hazards: Not applicable / not classified as marine pollutant according to the provided data.
• ADR hazard identification number (Kemmler): 33
• Tunnel restriction code: (D/E)
• Special provisions (ADR): 274, 601, 640C
• Special provisions (IMDG): 274, EmS F-E, S-E
• Special provisions (IATA): A3, ERG code 3H
• Limited quantity (all modes): 1 L

Section 8 – Personal protective measures

When handling Bostik PREP K, appropriate personal protective equipment (PPE) should be used, according to the safety data sheet.

Engineering controls

• Ensure adequate ventilation, especially in confined areas.
• Vapours or aerosols must be exhausted directly at the point of origin.

Eye and face protection

• Wear tightly sealing safety goggles.
• Use a face protection shield where there is a risk of splashing.
• Eye protection must conform to EN 166.

Hand protection

• Wear protective gloves made of suitable materials (e.g. rubber gloves).
• Gloves must comply with EN 374.
• Observe the breakthrough time specified by the glove supplier and replace gloves regularly or immediately if damaged.

Skin and body protection

• Wear appropriate protective clothing to prevent skin contact.
• Use antistatic footwear.
• Wear fire/flame resistant or flame-retardant clothing.
• Use an apron or other additional body protection where splashing is possible.

Respiratory protection

• In case of inadequate ventilation, wear suitable respiratory protection.
• For mist, spray or aerosol exposure, use a personal respiratory protection device and protective suit.
• Recommended filter type: organic gases and vapours filter conforming to EN 14387, for example a respirator according to EN 140 with filter type A or better.

Environmental exposure controls

• Do not allow the product to enter sewers, the ground or any body of water.