Cilbond® 48

Bonding Capabilities:

• Cilbond 48 is a one-component bonding system for hot and cold-cure PU’s and TPU’S to all metals during the curing process at temperatures of 20°C to 135°C for cast elastomers and up to 200C for TPU’s..
• Cilbond 48 will also bond PU’s and TPU’s to epoxies and fibreglass reinforced plastics, polyamides and other engineering thermoplastics, such as Hytrel® , PBT, PET, PPS, PPO, PEEK, PES, etc.

In-service Benefits:

• Cilbond 48 is especially suitable for use in dynamic conditions where hydrolytic stability is important, exhibiting no failure in the cement to metal bond.
• This is illustrated by tests where a 95o Shore A modified polyether TDI prepolymer / Ethacure 300 system was bonded to mild steel with Cilbond 48. It showed 100% rubber tear with peel loads of 1000N/25mm, when tested at 23C after total immersion for 15 days in pressurised tap water at 105°C.
• Cilbond 48 exhibits excellent salt-spray resistance, illustrated by bonding a polyether TDI prepolymer / Ethacure 300 to a mild steel substrate and tested at 35oC in a 5% salt solution for 700 hours. Results showed no edge corrosion or bond failure.

​​​​​Processing Benefits:

• Cilbond 48 is formulated with a fast-drying solvent system which dries quickly to give tack-free / non-blocking coatings. It will also bond without the need of a pre-bake, but will reliably withstand cycles of up to 24 hours at 100-110°C.

Where to use

• Cilbond 48 will bond all castable TDI, NDI and MDI prepolymer systems, MDI quasi systems, cold cure polyurethanes and TPU’s to metals and plastics (including fabrics and cord) at temperatures of 20°C to 135°C for cast elastomers and up to and even above 200C for TPU’s.
• It is especially suitable for use in dynamic conditions where hydrolytic stability is important, exhibiting no failure in the cement to metal bond.​​​​​​​

End applications for products using Cilbond 48 include :

• Rollers for the paper and textile industries, including rotationally cast PU rollers
• Solid tyres
• Carriage wheels
• Dunnage
• Pipe linings
• Pipe coatings
• Reinforced screen decks
• Belts
• Any product with an engineering bond between a PU elastomer and a metal or plastic substrate.

Cilbond 48 should also be considered for bonding PU’s to a range of RFL-treated and untreated fabrics and cords such as polyamide, Aramid, polyester and carbon fibre, as used in hose and belt construction.
Agitation: Cilbond 48 should be stirred prior to use.
Brushing: Application by brushing is normally undertaken without further dilution, but for coating large areas, dilution with MEK or the diluent blend shown below, improves flow and speed of application. The application of two thin coats is more consistent with good bonding than applying one thick coat.
Dipping: Dilute to a viscosity of 16-24 seconds using a Zahn No.2 cup at 25°C or 13-20 seconds using a Din 4 or Ford 4 Cup at 25°C. Use MEK if a fast drying coating is required, or MEK/Toluene blends if slow drying is required.
Spraying: Dilute to 16-24 seconds on a Zahn No 2 cup or 13-20 seconds on a DIN 4 or Ford 4 cup at 25°C, using up to 30% of the diluents shown below.
A nozzle size of 1.0 – 1.5mm and an air-pressure of 1.5 bar is recommended. Excessive air-pressures may lead to cob-webbing. If cob-webbing (fibrillation) occurs, use more
diluent containing more higher boiling solvent, such as MPA. If MEK is used as the sole diluent, beware of chilling the sprayed metal parts (due to rapid MEK evaporation) and subsequent condensation of water, which may lead to a micro porous film. It is normally preferred to use a diluent made up from MEK and toluene in the ratio of ca. 3:1 by weight or volume.
Diluents: See separate section below on the recommended diluent blends for brushing or spraying.
Roller Coating: The viscosity of Cilbond 48 may be too low for some roller application processes.
Drying: Dry each coat for at least 30 minutes, and the final coat for at least 45 minutes at room temperature of 23°C. At below 20°C, extend the drying time accordingly. Forced drying may be used (and is recommended for cold-cast PU’s with little or no exotherm), if care is taken to prevent blistering of the films, but use low temperatures (of up to 60°C) in the early stages of drying. Pre-warming parts to ~60oC prior to coating will also reduce drying time. For cold cast PU’s, where no heat input is possible, the final coat should be left to dry for several hours, preferably overnight, prior to casting the PU. Alternatively, consider Cilbond 41 for low temperature on-site bonding.
Pre-Baking:  Pre-baking is not usually required to develop good bonding to the substrate however if a pre-bake is necessary, CIL recommend using 1 hour at 100-110°C. The maximum pre- bake is 24 hours at 100-110C and pre-bakes at >120°C should be carefully controlled.
Coating thickness: For general-purpose applications use a dry coating thickness of 15 microns. For dynamic fatigue or severe environment applications use a dry coating of 25 microns.
PU casting: Cast the PU as directed by the PU manufacturer. For hot cast PU’s, always heat the coated metals up to the mould temperature/casting temperature. For cold cast PU’s and rotational casting it is important, in order to maximise the environmental resistance, to either extend the drying time (as described above) or preferably, heat the coated parts at 60-70°C for 30–60 minutes, prior to casting the PU and for very fast curing PU systems the moulding process can be conducted after the metals have cooled down, if it is absolutely necessary.
Post-Cures: Post curing is not required with Cilbond 48, but any post cure specified for the PU, will generally enhance the bond strength and the environmental resistance of the bond.
Storage:  Coated parts can be stored for up to 7 days, provided they are protected from dust and moisture, but ideally the PU should be cast within 48 hours.

Cilbond 48 is supplied in 10L, 25L and 200L containers. 250ml trial samples are also available upon request.