Peel resistance

Adhesives. Contact adhesives are blends of mbber, phenoHc resin, and additives suppHed in solvent or aqueous dispersion form they are typically appHed to both surfaces to be joined (80). Evaporation of the solvent leaves an adhesive film that forms a strong, peel-resistant bond. Contact adhesives are used widely in the furniture and constmction industries and also in the automotive and footwear industries. The phenoHc resins promote adhesion and act as tackifiers, usually at a concentration of 20—40%. In solvent-based contact adhesives, neoprene is preferred, whereas nitrile is used in specialty appHcations. The type and grade of phenoHc resin selected control tack time, bond strength, and durabiHty. 

Epidermal growths such as actinic keratosis, lentigines or thin seborrheic keratoses can all be treated effectively with 25-35% TCA peels. Thicker epidermal growths or growths involving the dermis will be more resistant to treatment such as hypertrophic actinic keratoses and thicker seborrheic keratoses and may even be resistant to a medium-depth peel. Resistant lesions many times are best treated with a combination of a medium-depth chemical peel and other modalities such as manual dermasanding or CO, laser. 

However, a laminate consisting of a layer of TPX, an intermediate layer of an adhesive resin composition and a layer of an olefin polymer has excellent peel resistance and can be easily controlled in the gas permeability (10). 

D 1876 Test Method for Peel Resistance of Adhesives (T-Peel Test)... 

D 3167 Test Method for Floating Roller Peel Resistance of Adhesives... 

ISO 4578 1979 Adhesives determination of peel resistance of high-strength adhesive bonds. Floating roller method. 

The testing of the peel resistance occurs according to the standard DIN EN 1464 Adhesives - determination of peel resistance of high-strength bonded joints - climbing drum peel test (respectively, T-peel test) and serves the determination of the resistance of bonded metal joints to peeling forces (Figure 10.5). 

When loading this test piece with force F it is noticed that, unlike in the tensile shear test, the force is not applied to an area A (= b x fu), but to a line X... X. The other area of the adhesive layer remains unstressed. Thus, in this case strength cannot be defined as force per area , but the force referring to a line is called peel resistance. If the test piece shown in Figure 10.5 is tom apart by means of force F, and the force over the peeled distance is recorded, the following peel diagram results (Figure 10.6). 

Peel resistance/strength Resistance of a bonded joint against linear acting peel forces generating high stress peaks in the adhesive layer, dimension N/mm or N/cm. 

At least one of the metal layers needs to be scratch/peel resistant, and this is usually the gate layer against the substrate, although other combinations are possible (e.g. source/drain layer can also bond well to the gate dielectric and be deposited over a via). A t3rpical solution is to place a via in the center... 

Fig. 13.8 The T-peel resistance as a function of the crosshead speed for nitrile rubber/phenolic polyurethane liquid rubber blend toughened epoxy (upper curve) and conventional nitrile rubber-toughened epoxy structural adhesives (lower curve).

FIGURE 3.77 Test panel and T-type test (T-peel test) specimen for peel resistance of adhesives (standard test method ASTM D1876-95). The bent, unbonded ends of test specimen are clamped in test grips of tensile testing machine and load applied at a constant head speed of 254 mm (10 in.). Average peeling load (in pounds per inch of specimen width) is determined for the first 127 mm (5 in.) of peeling after the initial peak. 

ASTM D1876-72(83). Peel Resistance of Adhesives (T-Peel Test), Annual Book of Standards, 15.06, American Society for Testing and Materials, 1986,... 

Clarke (7), as early as 1971, studied the behavior of a nitrile rubber modified, epoxy paste adhesive using the climbing drum peel strength test. Peeling resistance was... 

ASTM D3167-03a Standard test method for floating roller peel resistance. 

ASTM D 1781-76—Climbing drum peel test for adhesives ASTM D 1876-72—Peel resistance of adhesives (T-peel test)... 

ASTM D 3167-76—Floating roller peel resistance of adhesives... 

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