Лако-красочные материалы — производство

Since bases are catalysts for the curing reaction and acids are stabilizers for the cya­noacrylates, the pH value of the surface will control the cure speed. Surfaces that tend to be acidic will cure slowly compared to a neutral surface, which in turn will cure more slowly than an alkaline surface. In most applications the […]

A typical cure curve for 100-cP methyl cyanoacrylate is shown in Fig. 5. The speed of cure is influenced by the thickness of the bond, the activity of the surface, and the designed speed of the adhesive. 1. Versatile. There are few materials to which cyanoacrylate will not bond/adhere, even dissimilar materials (polyethylene, polypropylene, and […]

In general, standard industrial cyanoacrylates do not operate effectively above 180°F (see Fig. 4). However, the new allyl types of cyanoacrylates can operate as high as 480°F before the bond loses sufficient strength to be operationally effective (see Table 2). Allyl cyanoacrylates for metal-bonding applications have proven effective in wave solder and under-hood (automotive) applications. […]

The term cyanoacrylate comes from the chemical structure of these materials. Figure 1 depicts the general formula for cyanoacrylates. As the figure shows, cyanoacrylate adhe­sives are made up of carbon, hydrogen, oxygen, and nitrogen. The way these atoms are Figure 1 General formula for cyanoacrylate adhesives. arranged in the molecule is important because the arrangement […]

William G. Repensek National Starch and Chemical Company, Oak Creek, Wisconsin, U. S.A. I. INTRODUCTION Adhesives have been used since ancient times, but only since the advent of synthetic polymers (plastics) has their use become of major importance because manufacturers can now synthesize polymers and compound adhesive formulations to fit the requirements of the application. […]

Adhesive and coating advances allow electronics design and assembly engineers to meet new quality demands. They bring new cost considerations to electronics production, too. For example, conformal coatings, tacking adhesives, and potting compounds used in military electronics have stringent specifications because of the demanding environments in which they are used. Protection from high vibration, G-force […]

Because of the relatively higher resin costs, process improvement evaluations are replacing unit or batch cost considerations. Many of the new coatings and adhesives provide down­stream benefits, which, when factored into the overall cost of manufacturing, equal or reduce cost as compared to traditional coating technologies. For example, a highly filled epoxy resin, for potting […]

Categories of uses of UV aerobic acrylic adhesives are listed in Table 7. One category is the bonding and lamination of clear materials such as glass and plastics. Because UV aerobics exhibit high strength, toughness, and good structural properties, the second category has been designated ‘‘light welding’’: a process of joining parts by bridging the […]

Only initiators sensitive to long-wave UV light over 325 nm are used in UV aerobic acrylic adhesives. Long-wavelength UV light is sometimes referred to as ‘‘black light’’ and is generally considered harmless. Short-wavelength radiation, on the other hand, can pro­duce burns. (Sunburn from overexposure is a familiar example.) The high-intensity lamps listed in Table 6 […]

Ultraviolet curing grades of aerobic acrylics yield tough, impact-resistant, structural adhe­sives with tensile strengths up to 3000 psi when joining metal, plastic, glass, ceramics, and other substrates. Adhesive potting to 1 in. can be produced in a single exposure to high — intensity UV light. Transparent optical adhesives are also derived from this technology. Figure […]