Köraplast SF 600 g – PU Contact Adhesive (1K/2K) for Leather, Textile, PVC, ABS, PUR & Rubber

Köraplast SF 600 g – universal PU contact adhesive for cold bonding

Köraplast SF is a universal polyurethane (PU) contact adhesive designed for cold bonding in applications where the joint is exposed to high, long-term mechanical stress. It is typically used on leather, textiles, PVC, ABS, PUR and various rubber/crepe materials, including TR soles and latex parts. Thanks to its use as both a 1K and a 2K system, it fits standard production as well as demanding bonds requiring increased resistance.

Where it makes the most sense

This adhesive is intended for joints that take a beating: flexing, shear, peel, repeated loading, vibration. Typical examples include heavy-duty and sports footwear (sole-to-upper, reinforcements, edges) and truck tarpaulins or other technical textiles where fast processing and reliable performance are required.

Typical applications

• footwear manufacturing (work shoes, sports shoes, highly stressed bonds),
• technical textiles and laminated materials,
• tarpaulins and cover systems for commercial vehicles,
• repairs and maintenance requiring cold contact bonding.

1K vs 2K mode

Köraplast SF can be used as a one-component (1K) contact adhesive or as a two-component (2K) system with added hardener. The 2K mode is typically chosen when higher resistance is needed (e.g., demanding soles, plasticizers, tougher operating conditions). Hardener is usually added at 5–10% according to the process. After mixing, the working time (pot life) must be respected.

Cold contact bonding process

The principle is simple, but many failures come from skipping the key step: flash-off. Contact bonding is not “apply and stick immediately”.

1) Surface preparation

Substrates must be clean, dry, and free of dust, grease, and release agents. On difficult materials, light abrasion followed by degreasing is common practice. If you skip preparation, the joint may hold temporarily but will fail under load.

2) Adhesive application

Apply evenly to both bonding surfaces to form a continuous film without dry spots. For absorbent substrates, process adjustments may be required (e.g., a second coat).

3) Flash-off and joining

Cold bonding is typically achieved after a flash-off time of 5–20 minutes (depending on conditions, substrate, and coat weight). After flash-off, assemble the joint and press immediately. Uniform contact pressure over the entire bond area is critical.

4) Pressing

Pressing is typically measured in seconds (often 8–15 s depending on material hardness). The key factor is pressure and full-area contact, not extended time.

Reactivation if the open time is exceeded

If the flash-off time is exceeded, the bond can often be restored by heat reactivation – typically heating one side to approx. +40 to +50 °C, then assembling and pressing the joint. This is a practical way to reduce scrap in real production conditions.

Important processing conditions

Temperature matters. Do not apply or bond below approx. +18 °C (both adhesive and substrates). Low temperatures change viscosity and flash-off behavior and often lead to weak or unreliable bonds.

Performance benefits in practice

• Fast cold bonding without heat in typical applications.
• Optional 2K system for increased durability in the most demanding bonds.
• Clear adhesive film with good resistance to yellowing.
• Designed for heavily stressed joints where standard contact adhesives fail.

Packaging and storage

Supplied in a 600 g pack. Keep the container tightly closed (to limit solvent evaporation), store under recommended conditions and away from direct sunlight. Typical shelf life is around 12 months when stored correctly.

Product category

Köraplast SF belongs to the industrial chemicals range and is suitable for customers who need contact bonding of technical materials under high stress—most commonly footwear applications, technical textiles, and tarpaulin systems in transport.