Adhesion tests abrasion

The final part of the design and selection of conveying belts should consider characteristics of the solid, such as abrasiveness, moisture, temperature, stickiness, and adhesiveness. Testing should be performed for extreme. 

Referring to PVC values (zinc content in dry film), previous results of laboratory tests demonstrated that a higher amount of microzinc leads to a longer useful life of primers. Nevertheless, it is important to mention that the choice of zinc content must be made by considering the physical characteristic of the primer film required for each particular case. When pigment volume concentration exceeds largely the CPVC, film properties such as adhesion, flexibility, abrasion resistance, etc. are drastically reduced while when the percentual level is slight under the critical value the efficiency is also considerably diminished. 

Abrasion test (characterization) Testing film adhesion and abrasion resistance by rubbing, impacting, or sliding in contact with another surface or surfaces. Examples Tumble test, tabor test, eraser test. 

The characteristics of interior paints that require testing and analysis include hiding and appearance, package stabiHty, adhesion, spatter resistance, flow and leveling, color and sheen uniformity, touch-up, stain removal, burnish resistance, and block and print resistance. A popular test that assesses the wet abrasion resistance of an interior paint is to measure its scmb resistance. A mechanical device is used to scmb a paint film of a specified thickness with a standard bmsh and abrasive cleanser suspension. The number of scmb cycles (back and forth movements of the weighted bmsh) at various end points (first cut through, or 50% removal of the film) is then recorded. Scmb resistance usually holds steady or decreases slightly as PVC is increased, but drops quickly once the CPVC is exceeded in a paint formulation. 

Abrasion tests In these tests the end point is normally taken as the amount of abrasion required to penetrate the coating. The results thus reflect the strength of the coating, its cohesion, and in some cases its adhesion to the basis metal as well as resistance to abrasion. 

After cleaning by abrasion and with solvents, the polyimides can be stuck with a poly-imide, epoxy or acrylic resin adhesive whose thermal resistance is compatible with the operating conditions. Preliminary tests are essential. 

Typical industrial plastic selection criteria have focused on pin-on-disk tests (involving plastic sliding over steel) and sand slurry abrasion tests. The CMP environment, however, is very different from these typical industrial tests. In CMP, the retaining ring plastic is subjected to a plastic-to-plastic adhesive force component involving the polyurethane pad, chemical attack from the chemicals in the slurry, as well as an abrasive component associated with slurry particles. 

Film performance Film resistance tests are for hardness, abrasion, adhesion, flexibility, impact, scrubbability, and chemical and water resistance. 

Table VI also shows the relationship between the amount of hydrocarbon in the form of percent Ct and the relative fuse grade. The number of samples in Table VI is reduced from previous tables since many of the papers, because of their properties, were unable to withstand the abrasive fuse grade testing. For example, the sample with high levels of filler separated rather easily and pulled fibers from the surface, invalidating the test procedure. Even without these samples, however, a clear relationship between the amount of hydrocarbon on the surface, either in the form of rosin and rosin salts or lignin, is clearly related to the adhesion of the toner polymers to the paper surface. A least square fit of these data has a (relatively low) correlation coefficient of 0.85, and a slope of -0.8. Although the relationship may not be a linear one, it is clearly reasonable to presume that higher quantities of hydrocarbon on the surface of paper do prevent adequate adhesion of toner. This result corresponds with the previous work done by Borch(16) and also with results presented elsewhere in this symposium volume.

When polymers slide on machined metal surfaces, it is quite possible that steady-state wear Involves a combination of abrasive, fatigue, and adhesive wear mechanisms. To study fatigue wear, it would be desirable to minimize the contributions of the abrasive and adhesive wear modes. In this paper, the following polymers polycarbonate, polyvinyl chloride, ultra-high molecular weight polyethylene, siloxane modified epoxies, and polylmldes are tested in experiments in which the fatigue wear mode is predominant. 

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