Cilbond R-7327

Bonding Capabilities:

Cilbond R-7327 is a one-component bonding system developed to give high-performance bonding to metal
and plastic substrates with the following elastomers:-

• Natural Rubber (NR)
• Natural Rubber SEV (NR)
• Natural Rubber EV (NR)
• WDK NR60H (NR)
• Styrene Butadiene Rubber (SBR)
• Ethylene/Ethyl Acrylate, Vamac (AEM)
• Ethylene Propylene Diene Monomer (EPDM)

In-service Benefits:

• Exceptional salt spray resistance as either a one-component system, 30% stressed components exceed 900-1000 hours salt-spray without signs of corrosion and 1mm edge failure with grit blasted mild steel parts.
• Exceptional dynamic and static fatigue resistance.
• Superior chemical resistance to: Petroleum spirit fuels, unleaded petrol, kerosene, fuel oils, mineral oils and synthetic ester turbo oil at high temperature, ethylene glycol and propylene glycol at high temperature, acids and alkali, hot water, including boiling water.
• Resistance to both mild acid and mild alkali media.
• Superior chemical resistance to petroleum spirit, unleaded petrol, kerosene, fuel oils, mineral oils and synthetic ester turbo oil and ethylene glycol/propylene glycol at high temperature, hot/boiling water, steam.

Agitation: Stir thoroughly before use, preferably with a high-speed propeller type stirrer.
Brushing: Application by brushing is normally undertaken without further dilution, but for coating large areas dilute with 10-15% Toluene, Xylene or MEK.
Two thin coats are preferred to one thick coat.
Dipping: ​​​​​​​For dip application of Cilbond R-7327, dilution is necessary to reduce the viscosity to a level where correct film formation may be achieved. Dilute with Xylene to the following
viscosities : Viscosity Guide at 26°C :- DIN 4 Cup : 18 - 24 sec
                                                       Zahn Cup No 2 : 24 - 28 sec

At these viscosities Cilbond R-7327 may require as much as 25-40 part of diluent to 100 parts of Cilbond R-7327. If faster drying and thicker coats are required, replace all or part
of the diluent with MEK or MIBK. After dilution we recommend stirring on a continuous basis.
Spraying: ​​​​​​​For spray applications, Xylene is the preferred diluent, especially for reducing/eliminating cob webbing/fibre formation. Dilute to the following viscosities :
Viscosity Guide at 26°C :- DIN 4 Cup : 13 - 20 sec
                                   Zahn Cup No 2 : 16 - 24 sec

This may require as much as 30-50 part of diluent to 100 parts of Cilbond R-7327. MEK/Xylene and MIBK/Xylene blends are particularly effective diluents for spraying, especially where automated rapid processing is employed. Typically, use 1.5 - 2.0 bar air pressure with a fluid pressure of 0.5 - 1.0 bar, a nozzle size of 1.0 – 1.5mm when using an HVLP system, which is the preferred method of spray application. Note that excessive air pressure can cause fibrillation (cob-webbing).
Roller Coating: The viscosity of Cilbond R-7327 is close to that required for many roller coating applications, so little or no diluent is normally required. Fast drying solvents, such as MEK, are often the preferred for dilution..
Dilution: Toluene and especially Xylene are the main diluents for Cilbond R-7327. Other diluents, which may be useful include MEK, and MIBK, MEK and MIBK are best used in solvent blends with Toluene or Xylene. Regardless of which diluent is chosen, it is imperative that the cement be stirred vigorously whilst diluent is being added, otherwise gelation may result.
Drying: At room temperature drying takes 30 - 45 minutes. If the temperature is abnormally low, longer times will be required. Forced drying may be employed if desired to speed the operation. Large volumes of warm air will reduce the drying time to <<2 minutes and temperatures up to 50°C may be employed as necessary. Forced drying is a recommended process for Cilbond R-7327.
Pre-Baking: Cilbond R-7327 exhibits excellent pre-bake resistance and though this is partly compound dependent, Cilbond R-7327 can resist pre-bakes of 15-30 minutes at 160°C.
Film Thickness: Irrespective of the method of application for the bonding agent, it is vital to lay down as uniform a film as possible to obtain optimum and uniform bond strength results. We recommend the following :
General Purpose Bonding : 15 – 25 microns (dry coating thickness)
Superior Environmental Resistance : 25 – 35 microns (dry coating thickness)
In many cases, as for most so called one-coat systems, it is usually double applied.
Moulding: Cilbond R-7327 resists wiping, and mould fouling and may be used with all moulding methods including compression, transfer, injection, and extrusion moulding. Temperatures required to affect a bond may vary from 120-230°C. Fully dried Cilbond R-7327 show virtually no mould fouling or wiping/melt flow.
Storage: Coated parts may be stored for several weeks if protected from contamination by dust, oil mists, grease, and water.