Cross-hatch adhesion

AppHcation of an adhesion-promoting paint before metal spraying improves the coating. Color-coded paints, which indicate compatibiHty with specific plastics, can be appHed at 20 times the rate of grit blasting, typically at 0.025-mm dry film thickness. The main test and control method is cross-hatch adhesion. Among the most common plastics coated with such paints are polycarbonate, poly(phenylene ether), polystyrene, ABS, poly(vinyl chloride), polyethylene, polyester, and polyetherimide. 

Testing of Painted Products. The enhancement of paint adhesion is one of the principal functions of conversion coating (20—22). A group of tests based on product deformation is used to test the painted product. The appHance and cod-coating industries use the mandrel bend, the cross-hatch adhesion test, and the direct and reverse impact tests. Adhesion after a water soak is judged using a cross-hatch test performed on the exposed surface. 

Epoxy acrylate (Ebecryl 3700, 50%) combined with 25% TMPTA, 25% I BOA and with DIBF-OPPI-DIDMA pigment and FC-171 as above was also used to coat panels. These panels showed no removal of coating in the cross hatch adhesion test. With 6.8j there was no loosened coating on the frontal impact surface, and only 30% was loosened on the back surface. Five hundred grams were required to scratch to bare metal with the balanced beam. Performance was... 

ASTM-D 2794, units are in-lb, impact tester limit was 80 in.lb. ASTM-D 3363 < ASTM-D 3359,5B is 100% cross-hatch adhesion double rubs ASTM-D 522 ASTM-D 1400, General Electric thickness gauge type B, units are l/lOOO in. Sonset of transition, determined by DSC. 

The TPO parts are power washed and chlorinated polypropylene adhesion promoter, AP, is applied to the surface. To achieve sufficient paint adhesion, it is required that the AP thickness range is between 0.2-0.4 mils. Then the color coat, either IK or 2K is applied, flashed and followed by the application of a 1K or 2K clear coat. The entire system is cured in the paint oven usually at 121°C for 30 minutes. QC method TPO surface 1/ visual Painted part 1/ AP thickness ranging from 0.2-0.4 mils is measured via cross-section under the microscope, 2/ cross-hatch adhesion, 3/ other tests. 

In the treatment of plastics, the free radicals generated in the reaction chemically modify (ionize) the surface of the TPO thus allowing the color coat to attach itself to the polar TPO surface. The rest of the process is the same as in the Baseline above. QC method TPO surface 1/ FTIR 2/ surface tension Painted part 1/ cross-hatch adhesion 2/other tests. 

The TPO part is power washed and the olefinic color coat is applied on the untreated, non-polar TPO surface. The ability of the Kraton Liquid Polymer to be formulated into a production color coat is a recent development and the adhesion mechanism is believed to be based on diffusion of very similar materials into each other with the aid of heat and solvents during the paint bake cycle. There may be other adhesion mechanisms occurring simultaneously. QC method TPO surface 1/visual, on-line identifies the color of the pigmented color coat ranging in thickness between 0.9-1.2 mils Painted part 1/ cross-hatch adhesion, 2/ other tests. 

The above results suggest a potential for utilizing surface fluorinated plastics for modified atmosphere and vacuum packaging applications. If needed, the barrier properties can be improved further by vacuum metalization. Excellent adhesion was found for vacuum-deposited aluminum on this new fluorinated layer, achieving an adhesion index of 10 using the classical cross-hatch method. With this treatment method it was also possible to heat-seal PP or PE onto PET. 

Representative samples of the lacquered, metallized, or coated materials are taken and by means of a sharp knife a cross-hatched pattern of squares of dimensions 1 mm by 1 mm is cut into the surface. A strip of transparent adhesive tape of good quality is pressed firmly over the test area, then pulled away in a single continuous movement. Finally the test area is examined and whether squares have been removed (and in what number) noted. 

After exposure to such a sequence, the specimens should be tested for adhesion of the metal coating by means of the cross-hatch test described in Adhesion above. In a comparison with the unexposed control samples, there should be no deterioration in the adhesion of the coating, reflectivity, or the condition of the surface. 

Good adhesion to metals. Avatrel exhibits good adhesion (passes the cross-hatched tape test, ASTM D-3359-95a and IPG 650-TM) to metals such as Cu, Au, Al, Cr, Ti, and Si, as well as SiO2. Polyimides on the other hand require tie layers and adhesion promoters. 

Both coating systems were also assessed after the test for adhesion, using the cross-hatch test. 

The cross-hatch test made it clear that the polyaniline primer displayed the best adhesion, and also that here the corrosion was confined solely to the damaged cross-hatch area and the undermining effect was by far the smallest. 

Adhesion. Adhesion has been studied according to the so-called cross-hatch or tape test (ASTM D3359-78) on coatings with thickness of about 1.5 mil. 

Scotch-tape" test A method of evaluating the adhesion of a lacquer, paint, or printed label to a plastic substrate. Pressure-sensitive adhesive tape is applied to an area of the painted plastic article, which may first be cross-hatched with scored... 

Resin used in paint Adhesion by Cross-hatch test (B.S. AU 148) Taber Abrasion Loss (mg) after 1000 cycles (U.S. Standard No.141a method No. 6192) Cupping Test Depth of indentation (min) (B.S. 3900 Part E4) Elongation Test Minimum % elongation that produces cracks (ASTM D522-60)... 

The difference between a screen and a stencil is in their respective structures, as shown in Fig. 40.16b, c. The screen is comprised of two layers the emulsion layer and the actual screen that supports the emulsion layer. The apertures through which the adhesive or solder paste is deposited are created in the emulsion by photoimaging techniques. The adhesive or solder paste simply flows past the screen cross-hatched wires. 

Exposure to 100% relative humidity at 40°C, cross hatch - DIN EN ISO 2409, Rating 0 - None and 5 - Complete loss of adhesion. 

Salt spray testing was carried out at 35°C within a 5% NaCl spray at 100% humidity for 500 h. Samples were checked every 48 h and images were recorded to compare the performance of samples throughout the test period. To assess adhesion, a Sellotape test was carried out as follows the samples were scratched using a razor blade to form a cross-hatch pattern. Sellotape tape was applied to the cross-hatch and fixed well before peeling it from the surface. The Sellotape was examined for signs of detachment of the coating. 

Tape test A series of cross-hatched cuts are applied to the coating, a pressure-sensitive tape is applied and pulled off. Adhesion is measured by the percent of material that is not pulled off by the tape. Human elements are present in this test because of variations in tape application pressure and the rate and angle of pull. ASTM D 3359... 

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