Interior adhesion 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. 

Hardwood plywood products are decorative in nature and are designed for interior use. Over 95X of all hardwood plywood is made with urea-formaldehyde adhesives. Responding to concerns about formaldehyde and certain wood products, test methods for measuring surface emissions were developed in the early 1980 s. Emissions from most hardwood plywood and particleboard products have decreased 65% to 95% in recent years primarily by use of low emitting UF adhesives and/or scavengers. Good correlation has been demonstrated between product test methods and indoor levels of formaldehyde in experimental manufactured homes. Decorative surface finishes can act to either increase or decrease surface emissions, depending on the nature of the finish and the substrate. 

The simplest and most economical type of durability testing is probably immersion in water. Even when the final application for an adhesive joint is in a protected and interior type service, it still may be assuring and practical to show that the joint can survive some limited degree of water contact or higher than ambient humidity exposure. We need to remember that component parts or even whole structures may be temporarily stored or shipped under conditions where water or high humidity may be present. This short exposure of a low durability joint may be enough to weaken it and make survival questionable for long-term service even under mild conditions. 

D-3024. Specification for Protein-Base Adhesives for Structural Laminated Wood Products for Use Under Interior (Diy Use) Exposure Conditions. Employs the D-0>905 block shear, D-0906 plywood shear, and D-4300 mold resistance tests to evaluate mostly casein-base adhesives for use in interior grade laminated beams. 

D-3110. Specification for Adhesives Used in Nonstructural Glued Lumber Products. Employs the D-0905 block shear test and a finger joint test, along with several exposures, to evaluate interior and semi-exterior adhesives, in end, edge and face bonded joints, especially for the molding and millwork field. Most of the applicable adhesives are based on polyvinyl acetate. 

D-0905. Test Method for Strength Properties of Adhesive Bonds in shear by Compression Loading (Fig. 8). A basic compression shear test which is widely used in screening wood glues. It is also used in specifications D-3110 (on nonstructural wood laminating ad hesives), D-2559 and D-3024 (on exterior and interior structural wood laminating adhesives respectively) and D-4317 (on polyvinyl acetate based wood adhesives). 

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