1. PRODUCT
DESCRIPTION
CLEARCLAD ANODIC electropaint systems combine all the
advantages of the application technology with outstanding chemical resistance, high build
capability to confer wear resistance, and excellent weathering properties due to a high
degree of UV resistance. These together with excellent decorative properties make
CLEARCLAD ANODIC an advanced coating system for selected substrates in a wide range of
applications (see section 7).
2. SUPPLY FORM
The base resin concentrate of CLEARCLAD ANODIC is a tan
colored, free flowing liquid of moderate viscosity. Pigmented and matte variants will vary
in appearance and viscosity accordingly.
Packaging is 20 kg American Pails. Other packing types and
sizes may be available on request.
3. SUPPLY SPECIFICATION
This will vary according to product type. The base resin
concentrate is supplied in ready-to-dilute form, solids content 45 - 50% by weight
(determined gravimetrically at 120oC for 1 hour).
4. METHOD OF DILUTION
CLEARCLAD ANODIC concentrates should always be pre-mixed with
either high purity demineralised water, or bath material at coating solids, when making a
new bath or replenishing an existing bath respectively.
Pre-mixing must take place in a suitable clean vessel
equipped with a motorized stirrer. Diluting material is added gradually to the
concentrate, under stir, until a solids content of less than 18% is achieved. At this
stage, at least 10 minutes stirring is applied to achieve complete emulsification.
Subsequently, this pre-mix may then be further diluted to the required solids or added to
the bath as appropriate.
CLEARCLAD ANODIC concentrates must never be added directly
into demineralised water or into the bath without this pre-mixing procedure.
5. CONDITIONING OF NEW BATHS
A period of at least 24 hours, and preferably 48 hours,
should elapse between initial bath make up and commencement of production. During this
time, the bath should be kept circulating through adequate particle filtration at its
normal operating temperature, and at least one bath volume of ultrafiltrate permeate
should be eliminated. Solvent loss due to permeate elimination is not significant, but the
MEQ (corrected) should be maintained at a minimum value of 50 by appropriate additions of
CLEARCLAD ANODIC Emulsion Stabilizer.
6. BATH OPERATING PARAMETERS
| Parameter |
Range |
| Solids %w/w |
8.0 - 10.0 |
| pH |
7.0 - 8.0 |
| Conductivity
(microsiemens/cm) |
800 - 1100 |
| MEQ @ 10% solids |
50 - 70 |
| Solvent PM A264 %w/w |
3.0 - 6.0 |
| Operating temperature oC |
23 - 29 |
| Coating voltage |
30 - 120 dependent upon load type and
required thickness. (up to 30 microns available) |
| Coating time (seconds) |
60 - 120 as above |
| Curing schedule |
160 oC metal temperature:
for minimum 20 minutes |
| Particle filtration |
1 micron cartridge type for clear or
tinted products. Higher micron ratings required for matted and pigmented systems. |
| Ultrafiltration |
Preferably used in conjuction with TRAP
UF/ion exchange system. Approx 10% permeate production should be routinely eliminated on a
contiuous basis during production. |
| Bath temperature control |
Heating , if applicable should preferably
be via indirect means. Direct heating should only be via low wattage quartz type immersion
heaters. Always take advice on this. Cooling may be effected via immersed stainless steel
coils using circulating cold water as the cooling medium. Any control system should be
capable of maintaining the recommended operating temperature +/- 1oC. |
| Circulation |
Continuous pumped circulation from a skim
weir and return via submerged sparge pipe. Circulation turnover rate for clear and tinted
systems is 3 - 5 bath volumes per hour. Matte and pigmented systems require 8 - 10 bath
volumes per hour. |
| Cathodes |
316 grade stainless steel. Anode to
cathode ratio 1:1 |
| Bath turnover rate |
In order to maintain the optimum
properties, the feed replenishment rate should be consistent with one bath turnover within
three months. |
7. SUITABLE SUBSTRATES
Anodic electropaint systems are deposited by a mechanism
involving liberation of oxygen and creation of an acid pH at the anode surface. This will
dissolve and oxidatively degrade many metals and so limits the application of anodic
electropaints in these cases. However, certain metals, most notably aluminium, positively
benefit from the formation of an adherent oxide layer between the underlying metal and the
electropaint coating. This situation enhances adhesion and corrosion resistance. LVH have
special process modifications for CLEARCLAD ANODIC enabling outstanding adhesion &
physical and chemical resistance over aluminium for very demanding applications.
Other suitable substrates are :
- phosphated mild steel
- certain grades of stainless steel
- gold
- nickel and chrome electroplate
- magnesium.
CLEARCLAD ANODIC can provide a superior coating system over
particular substrate/treatment combinations, but any such system design should be the
subject of careful evaluation. Advice is available from LVH or the local CLEARCLAD
supplier.
8. ASSESMENT OF CURE
This appropriate degree of cure (polymerization) should be
established for the particular application and this should be related to the resistance to
a solvent rub test. In this way, a quick end-of-line test for correct degree of cure can
be established. Obviously, this is a destructive test even in the case of a pass, and so
when it is applied to selected production pieces as part of a quality control procedure,
the pieces should be discarded or re-worked as appropriate.
9. COVERING POWER
One kilo of the base resin concentrate of CLEARCLAD ANODIC
will apply a coating of 1 micron over approx. 450 sq.metres assuming 100% efficiency.
Near to 100% efficiency can be achieved using closed-loop
ultrafiltration reclaim. Without a reclaim system, efficiency and consequently covering
power will reduce.
"Tinted" systems, using relatively low
concentrations of colorants, will have covering power very similar to the base resin
concentrate. Other types of pigmented systems, incorporating significant concentrations of
dense colorants or matting agents will have lower covering power. This will depend
entirely on the particular product and such information will form part of the appropriate
data sheet.
10. RESISTANCE OF CLEARCLAD ANODIC COATING TO ULTRAVIOLET
LIGHT
In addition to CLEARCLAD ANODIC's outstanding resistance to a
great variety of chemicals, it has been formulated to have high resistance to UV light in
order to render it suitable for exterior applications where resistance to the effects of
weather is essential. As a transparent coating, its UV resistance is comparable to the
best available exterior-quality acrylics or polyesters. Its ability to fix dyes is not as
good as CLEARCLAD cathodic products and so for the popular "tinted" effects over
reflective base metals it is recommended that high performance cathodic products such as
CLEARCLAD HSR are selected. However, for certain opaque colours - including white and
black - over the preferred substrates, CLEARCLAD ANODIC provides an outstanding high build
electropaint system with excellent resistance to colour change and chalking.
11. CORROSION PROTECTION AFFORDED BY CLEARCLAD ANODIC
COATING
The resistance to corrosion of any coated metal is always
determined by the particular "system" - which means a combination of the base
metal, its pretreatment, the type of coating applied, and the thickness and type of
pigmentation of the coating.
CLEARCLAD ANODIC is effectively a one-coat paint system.
Accordingly, its corrosion-protective properties will be principally influenced by its
thickness and quality of adhesion to the base metal. In this way, CLEARCLAD ANODIC will
provide a barrier (optimized by its thickness) to corrosive agents, and a resist against
spread of corrosion (optimized by its adhesive strength). Further than this, the intrinsic
corrosion resistance of the base metal should be optimized, for example by the chromating
of aluminum or phosphating of steel. Proper preparation of the base metal will both
increase the intrinsic corrosion resistance and enhance the adhesion of CLEARCLAD ANODIC,
both factors combining to optimize the corrosion resistance of the whole system.
12. WEAR AND ABRASION RESISTANCE
CLEARCLAD ANODIC has good intrinsic abrasion resistance (as
determined by ASTM D968 Falling Sand test - 25 litres/25 micron thickness) over a wide
range of cure levels. This in combination with it being a high-build product (30 micron
thickness readily available) affords a high degree of wear and abrasion protection. As the
absolute wear property of organic coatings is principally a function of thickness,
applications demanding wear resistance should utilize the higher thickness available with
CLEARCLAD ANODIC.
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CLEARCLAD
HSR