CILBOND® 49SF

• One-coat solution
• High-temperature resistance in service
• High pre-bake resistance
• Extreme chemical resistance
• Bonds wide range of PU systems
• Sprayable with CILBOND Diluent 4000
•  Clear or pigmented color offerings
• Reduce process cost and increased productivity
•  Improve performance on high-temp applications
•  Reduce rework and expand process window
•  Protection of substrate to extend product life
•  Reduce product complexity
•  Allows for automation and uniform coating
•  Eliminates visual bond line or improve QC process with pigment

Metal Surface Preparation

• Cilbond 49SF must be applied to carefully prepared surfaces for it to be effective. Surfaces should ideally be grit blasted with clean, filtered sharp alumina or steel grit (200-400μ), and solvent degreased. For cast PU’s it is vital that when dealing with hard surfaces, such as case hardened steel, stainless steel and some grades of high carbon cast iron, that the grit is capable of giving a sharp surface.
• Alternatively, surfaces may be phosphated using well-established proprietary procedures. Good metal preparation is vital if the environment is continually wet such as sub sea situations and/or involves severe dynamic fatigue.

Applying Cilbond 49SF

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.

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 using the diluent blend given below, or use MEK if a fast drying coating is required.

Spraying: We recommend an HVLP gun using 1.5 Bar air-pressure and a nozzle size of 1 - 1.5mm. 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 the diluent shown below. If fibrillation (cob webbing) occurs, use diluent containing more higher boiling solvent, such as MPA. Cilbond Diluent 4000 is a suitable diluent for Cilbond 49SF. Typically, dilute ca. 100 parts of CILBOND 49SF with 40-70 parts Cilbond Diluent 4000, by weight or volume, depending on the gun type, the nozzle size and pressures used. If MEK is used as the main diluent, beware of chiling of the sprayed metal parts (due to rapid MEK
evaporation) and subsequent condensation of water, which may lead to a micro porous film.

Roller Coating: Dilute to 35-45 seconds on a DIN 4 or Ford 4 cup at 25°C for most roller application processes. Dilution with a high boiling solvent like MPA may be necessary to achieve the best finish and to reduce the skinning of the bonding agent in the applicator.

Drying: Dry each coat for at least 45 minutes and the final coat for at least 1 hour at room temperature (25°C). At temperatures below 20°C extend the drying time accordingly.
Forced drying may be used provided care is taken to prevent blistering of the films so we recommend temperatures below 60°C in the early stages of drying. Pre-warming the parts before coating will also aid drying (60°C is recommended).

Pre-baking: Pre-baking is required to develop good bonding to the substrate, especially to metals. The minimum pre-bake is 1 hour at 100°C and a typical recommended pre bake is 2 hours at 100-110°C, though it is well established that longer pre-bakes (4-8 hrs at 100°C) do maximize bond strengths,
percentage bond retention and especially the heat resistance of the bond and environmental resistance. The Cilbond 49SF coating should not be pre-baked for more than 48 hours at
temperatures of ca. 100°C, 24 hours at 110°C or 16 hours at 130°C.

Pre-bakes at >130°C should be fully validated and very carefully controlled and especially with porous and hardened metals (particularly cast iron and cast aluminum) as de-gassing may affect the cement to metal bond. As an alternative to extended pre-bakes, consider using Cilbond 49SF+ Cilcure B as a primer under

Pre-bakes prior to TPU injection molding are less sensitive to this problem, partly due to the high injection pressures and temperatures involved, which will re-bond the Cilbond 49SF to the metal.

Coating Thickness: For general-purpose applications use a dry coating thickness of 15 microns. For dynamic fatigue applications use a dry coating thickness of ≥20 microns.
For severe environments use a dry coating thickness of ≥25 microns. Under these conditions it is possible to achieve bonds, which exhibit no sign of edge failure after 480 hours salt spray tests, especially with Cilbond 49SF + Cilcure B.

Cilbond 49SF will bond castable and thermoplastic polyurethanes to metals and plastics at temperatures of 70°C or above, though best results are achieved at >85°C, particularly if the component is going to be subjected to a severe environment. It is especially suitable for use in dynamic conditions where hydrolytic stability is important.

When bonding MDI Quasi Prepolymer Systems and where the cast PU bond line may not reach much above 70°C, it is recommended that after applying the Cilbond 49SF, the coated metal parts are dried thoroughly and then pre-baked for an absolute minimum of 1 hr at 85°C - 100°C to ensure a good cement to metal bond.

End-use Applications Of Cilbond 49SF
End applications for products using Cilbond 49SF include :

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

When To Use Cilbond 49SF + Cilcure B

• If bond line temperatures are likely to be below 70°C, or if a pre-bake of the coated substrates is not feasible, or if the in-service environment is extreme, then consider the use of Cilbond 48 (see separate Technical Data Sheet) or Cilbond® 49SF + Cilcure B.
• Applications for Cilbond 49SF+ Cilcure B include low-temperature casting or spraying of PU’s, the rotational casting of small and medium sized rollers and applications involving dynamic fatigue at temperatures of ≥140°C.
• CIL strongly recommend Cilbond 49SF+ Cilcure B for applications that involve continuous use in aqueous environments. The resistance of PU to metal bonds made with Cilbond 49SF+ Cilcure B at a ratio of 100:10 and subjected to water at <50°C is predicted to be ≥ 20 years and the use of Cilbond 49SF as a cover coat iscovered below.
• Cilbond 49SF+ Cilcure B yields bonds capable of withstanding boiling water for up to 105°C for ≥200 hours.
• Cilbond 49SF+ Cilcure B gives improved adhesion to many substrates; especially epoxy resins, such as FBE, GRP/FRP, glass, ceramics, etc.
• Cilbond 49SF+ Cilcure B is recommended for highly plasticised PU systems and for systems where the curing agent could potentially solvate the bonding agent layer, such as trans CHDI/CHDM PU systems.
• Cilbond 49SF+ Cilcure B or Cilbond 49SF+ Cilcure B as a primer under Cilbond 49SF produce bonds capable of withstanding temperature of up to 180°C.

How To Use Cilbond 49SF With Cilcure B

• The standard mix ratio of Cilbond 49SF + Cilcure B is 100:10 by weight, but for some applications, it may be possible to use a mix ratio down to 100:5, especially for very fast cure 2 component PU’s.
• Cilbond 49SF (100 parts by weight) should be mixed with Cilcure B (10 parts by weight), preferably by adding the Cilcure B to the Cilbond 49SF, whilst stirring. Stir well until homogeneous. Allow to stand for a few minutes, stir again and it is then ready for use.
• Ideally make up sufficient mix to last ca. 8 hours, which is the recommended pot life. Dispose of any material after this, especially if it has a gelatinous nature.
• Apply this mixture following the same procedure as for Cilbond 49SF, except that a pre-bake is now not a definite requirement, though the dried parts must be brought up to the moulding temperature or to ≥50°C prior to casting the PU. If parts are dried at ≥70°C, then best bonding is achieved, even if the metals are at ≥50°C when the PU is cast.
• A high temperature pre-bake is possible, but it must be stressed that long pre-bakes must be avoided, though the system will tolerate up to ca. 4 hours pre-bake at 100-110°C without any adverse effect on bonding.
• Longer and higher temperature pre-bakes may be possible, depending on PU type, i.e. Vulkollan®. However this must be fully validated to ascertain reproducible results.

End Use Applications Of Cilbond 49SF + Cilcure B
Applications benefiting from Cilbond 49SF + Cilcure B include:

• Low temperature applied spray coatings and any difficult to bond very fast curing PU.
• Low temperature casting of PU’s, especially rotational casting of small and medium sized rollers and pipe, where some limited heat input is possible
• Applications required to withstand boiling water, hot water, where bonded items are continually in aqueous environments or where the bonds must survive up to 180°C.
• Applications where aggressive solvents are employed.

Cilbond 49SF + Cilcure B As A Primer Under Cilbond 49SF

• This combination is used for those applications where the benefits of Cilbond 49SF + Cilcure B as a primer can be combined with the long open time and pre-bake resistance of Cilbond 49SF, with the added advantage that this system gives bonds with the same heat resistance as Cilbond 49SF+ Cilcure B on its own.
• A primer coat of Cilbond 49SF + Cilcure B is 100:10 by weight is applied to well prepared metals to give a minimum of 15μ dry coating thickness and dried for 1-2 hrs at ambient temperature or with gentle applied heat. A second coat of Cilbond 49SF is applied to give a total coating thickness of ≥25μ and dried thoroughly.
• This system is now treated as though it was a dried coating of Cilbond 49SF to produce the bonded component and bond performance is equal to using Cilbond 49SF + Cilcure B at 100:10 by weight.

Cilbond 49SF is supplied in 10L, 25L and 200L containers. 250ml trial samples are also available upon request.

Coated parts may be stored for long periods of time (several weeks) provided they are protected from dust and moisture.

Shelf Life: 24 Months from Date of Manufacture.