Pipes and Fittings for the water and aqueous chemicals industries.

SUMMARY OF ESSENTIAL COATING REQUIRMENTS

1. The metalwork must be either grit-blasted or chemically pre-treated prior to coating.*
2. For Corona guns set the voltage at 30-50kV, or use overspray setting, or set amps to 10-20 microamps.
3. Heating schedule typically as polyester (see below). Ensure metal temperature exceeds 150°C.*
4. Thickness must be a minimum of 170 microns. (See note 2 re voltage above. This may also require a longer spraying time or increased powder supply. This thickness should be checked periodically.
5. Galvanised substrates may need degassing.
6. Do NOT use any cured resin based pre-treatment system (e.g. acrylics)
7. Adhesion checks should be carries out at regular intervals.*

*See "PPA 571 Processing Guide".

The metal must be degreased and all mill scale and corrosion products removed.

Mild steel should be solvent degreased then either grit blasted to Swedish Standard SA 2½ to 3 or phosphated. Galvanised steel should be solvent degreased if necessary. Then either grit blasted at 0.3MPa (40 psi) using a fine grit (0.2 to 0.5mm) or treated with a phosphate system. To achieve the maximum long-term adhesion, Plascoat recommend the use of zinc phosphate systems on both steel and galvanised steel. If chemical pre-treatment is used it is essential to remove any previously applied resin based pre-treatment systems. Discuss this with your pre-treatment supplier.

Aluminium should be degreased to remove lubricants and processing soaps. For most purposes no further treatment is necessary. However for maximum long term corrosion resistance chromate treatment is recommended.

When the powder is applied using a Corona Discharge gun a negative polarity is required. A voltage of 30-50 KV or 10-20 microamps is recommended. Plascoat PPA 571 HES can also be applied by Tribocharge guns. The heating schedule should be 180°C to 240°C for 5-40 mins depending on metal thickness. To ensure optimum adhesion, the metal temperature during processing must exceed 150°C. Since Plascoat PPA 571 HES is a thermoplastic there is no cross-linking to take place. Therefore when the powder has melted to form a smooth coating no further heating is required.

Overheating can cause craters to form in the coating or the coating to reduce gloss. It may also cause the coating to discolour in storage or in service. Thicknesses outside the recommended range may be detrimental to the properties of the coating.

Do not cure thermosetting powder paints with PPA 571 HES. The fumes from such systems can affect the surface of the PPA 571 HES coatings.

Note: If PPA 571 HES over-sprayed powder is to be recycled, then blend a maximum of 25% of this over-sprayed powder with 75% unused powder.

For typical properties of the coating see below.

*These values may vary from colour to colour

Stored in a clean dry area at 10-30°C and out of sunlight, the material should not deteriorate. However, in the interest of good housekeeping, old stocks should be used first.

Plascoat PPA 571 HES is supplied as a finely divided powder. Whilst there are no known health hazards associated with PPA 571 HES, normal handling precautions for dealing with fine organic powders should be taken - i.e. excessive dust generation and inhaling of the powder should be avoided. Facilities may be required for removing excess dust from the working area during the coating of more difficult items.

As with all polymeric powders, the material can ignite if brought into contact with a high temperature source or ignition - particularly in the fluidised condition.

Reference should be made to Plascoat Health and Safety Data Sheet HS504, available on request.

Should the coating be required for contact with food or potable water, further details should be obtained from Plascoat.

Recommended Coating Thickness

170-300 µ by electrostatic spray

200-800 µ by "flock spraying"

Appearance

Smooth/Glossy

Gloss

ISO 2813

60

Impact Strength

Gardner (drop weight) ISO 6272

Direct 23°C

3 Joules

Tested on 6mm thick mild steel plate with a 500 micron coating

Abrasion

Taber ASTM D4060/84

H18, 500g load, 1000 cycles

50 mg weight loss

Salt Spray

ISO 7253

Steel - Scribed

- Unscribed

Aluminium - Scribed

- Inscribed

Results after 1000 hours

Loss of adhesion less than 10 mm from scribe

Under film corrosion 1.0 mm

No loss of adhesion

No loss of adhesion

No loss of adhesion

Chemical Resistance*

- Dilute Acids 60°C

- Dilute Alkali 60°C

- Salts (except peroxides) 60°C

- Solvents 23°C

Good

Good

Good

Poor

Adhesion

PSL, TM 19

A-1

Weathering

QUV ASTM G53-77

Florida 45° facing South

2000 hrs - No significant change in colour or loss of gloss.

3 years - No significant change in colour or loss of gloss

Burning Characteristics

Ignitability **

Surface spread of flame **

Flammability

BS476: Pt5: 1979

500 micron coating

BS476: Pt7: 1979

300 micron coating

UL94

P = not easily ignitable

Class 1

V_o (see also Properties of Material)

Safe Working Temperature

(Continuous in air)

70°C max

Plascoat is committed to the manufacture and supply of a wide range of thermoplastic coating powders. This service is backed by the unrivalled experience of over 50 years of powder coating application.

With a policy of continuous improvement to its range of products, Plascoat reserves the right to alter or amend any item. Stringent quality control procedures are carried out at every relevant stage of manufacture and Plascoat operates a quality management system approved by BSI in accordance with ISO 9001:2000.

Plascoat is a subsidiary member of the IPT Group of companies.

Plascoat is a UK registered trade name.

It should be appreciated that the information given here is, to the best of our knowledge, true and accurate. However, since conditions under which our materials and equipment may be used are beyond our control, recommendations are made without warranty or guarantee.