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Adhesion of final layer

Adhesion of final layer

We test new properties of the surface sintered from modified powder or adhesion of modified material by itself using following methods:

  • scratch test
  • measurement of direct stress of the bond (metal-polymer-metal, polymer-metal)
  • cross-cut test – test I., II.
  • abrasion tester – test III.
Test I – adhesion of final layer – cross-cut test according to ISO 2409

Water based paint was applied by spraying on the sintered surface to cover it in sufficient amount without any additional pre-treatment (primer, flame, roughing) of the surface. Then a test of adhesion was done using cross cut method according to the ISO 2409 and evaluated according to attached etalons. Samples from modified material show very good results, when evaluation corresponds to classification No 5 for the unmodified sample (on the left) and classification No 0 or 1 for modified one (on the right).

Adhesion test using cross cut method for water based paint on the sintered surface from unmodified PE

Adhesion test using cross cut method for water based paint on the sintered surface from modified PE

Test II – adhesion of final layer – cross-cut according to ISO 2409 after absorption in water

Absorption of the samples sintered from modified powder, painted with water based, color in distillated water at 70 °C for 24 hours

Before exposition (adhesion – cross-cut 2 mm)

Sample
SGX 85
SGX 38
front side
Gt0
N.A.
back side
Gt0-1
N.A.

After exposition (adhesion – cross-cut 2 mm)

Sample
SGX 85
SGX 38
front side
Gt0
Gt0
back side
Gt0
Gt0

(Gt0 = the best, Gt5 = the worst).

Determination of stone-chip resistance of coatings according to ISO 20567-1, 1 cycle

Sample
SGX 85
SGX 38
front side
N.A.
St 0,5 (0,2 %)
back side
N.A.
St 0,5 (0,2 %)

Degree of destruction 0,5 = the best, degree of destruction 5 = the worst, see photo below

Elcometer 1720 Abrasion, Scrubbing and Washability Tester
Pure varnish

30 000 cycles

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Varnish mixed with 10 % by volume modified PE powder

135 000 cycles

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