Лако-красочные материалы — производство

The universally accepted method for testing adhesion under shear is a static load test [21], where a known surface area of the adhesive-coated product is applied under controlled conditions to a standard test surface, usually stainless steel or a standard cardboard, or even the product’s own backing. Then this is secured vertically, plus a 2°tilt-back, […]

Although slight differences occur here and there, the universally recognized method to determine how well a pressure-sensitive system adheres is to apply the adhesive, which has been pre-coated onto a flexible carrier, to a rigid standardized test panel under very controlled conditions and environment, using a roller of standard weight, dimensions, and construction, in order […]

John Johnston Consultant, Charlotte, North Carolina, U. S.A. I. INTRODUCTION It is assumed in almost all cases, that any pressure-sensitive adhesive to be tested has already been applied to a flexible carrier, which is either in tape form, or which can be cut into tapes for testing, virtually all test methods making this assumption. If […]

As noted earlier, the most commonly used standards for determination of adhesive joint properties and characteristics suggest reporting the results in terms, of average stress at failure. If average stress criteria were generally valid, one would anticipate that a doubling of the bond area should result in a proportionate increase in joint strength. Studies in […]

Adhesives are often used in applications where they are exposed to continuous or inter­mittent loads over long periods. It is difficult to duplicate such conditions in the labora­tory. Neither is adhesive testing and/or observation under actual service conditions a very feasible alternative. The designer is not usually able or willing to await the results of […]

Another common type of test is the peel test. Figure 8 shows four common types of peel specimens. One can understand the test described in ASTM D-1876 by examining Fig. 8a. Figure 8 Some standard peel test geometries: (a) T-peel test specimen, ASTM D-1876; (b) typical testing jig used in ASTM D-1876; (c) climbing drum […]

Some of the most commonly used adhesive joint strength tests fall under the general category of lap shear tests. Such samples are relatively easy to construct and closely resemble the geometry of many practical joints. The stress distribution for lap joints is far from uniform, but again the test results are commonly reported as load […]

Given the choice, a designer seldom uses adhesives in a direct tensile loading mode. The primary reason for this is probably related to the fact that by overlapping, scarfing, and so on, the contact area of the adhesive may be markedly increased over that of a simple butt joint. The finger joints used to produce […]

A relatively large number of tests have been proposed and formalized for evaluating the strength of an adhesive. Although there are some important exceptions (some covered in the following sections), the majority of the long-standing adhesive joint strength tests fall in three categories: tensile, shear, and peel.

Tests are performed for a wide variety of different reasons. Many tests have as a goal to compare different materials, procedures, products, and so on. For such comparisons to be meaningful, it is important that some type of standard procedure be used to obtain the information that will be used for comparison. This is, of […]