Лако-красочные материалы — производство

The cure speed and adhesion of an anaerobic sealant can be increased by treatment of the surface with a solution containing activating chemicals. Early anaerobic thread lockers were strongly affected by part cleanliness, and degreasing the parts with a chlorinated solvent improved performance dramatically. The condensation product of an aldehyde and a primary or secondary […]

The wide variety of applications of anaerobic adhesives and sealants is made possible by the modifications that make the viscosity appropriate to the application. An application that requires penetration into close-fitting parts should have very low viscosity, while a product used with large, loose-fitting parts should have a high viscosity. A styrene acrylate copolymer could […]

The monomers used in anaerobic adhesives and sealants generally contain at least one free-radical stabilizer, such as hydroquinone or p-methoxyphenol. It was found that ben- zoquinone, naphthoquinone, and similar compounds provided improved shelf stability without retarding the anaerobic cure [56]. It was also found that anaerobic formulations could be stabilized with a stable nitroxide free […]

The first accelerator used in an anaerobic adhesive was tributylamine [45]. Saccharin was also found to be an effective accelerator [46] and the combination of saccharin and N, N-dimethyl-p-toluidine was particularly effective if properly stabilized [47]. A large number of patents have been issued on various accelerators and combinations thereof. N-Aminorhodanine (XLIX) [48], 1-acetyl-2-phenylhydrazine (VI) […]

The most commonly used initiator for anaerobic adhesives is cumene hydroperoxide. Many other hydroperoxides have been disclosed, such as t-butylhydroperoxide (XL), p-menthane hydroperoxide (XLI), diisopropylbenzene hydroperoxide (XLII), pinene hydroperoxide (XLIII), and methyl ethyl ketone hydroperoxide (XLIV) [40]. Some diperoxides, such as di-t-butylperoxide (XLV) and dicumylperoxide (XLVI), have been claimed, but these may function only because […]

The first anaerobic patents mentioned only the polyglycol dimethacrylates with tetraethy — lene glycol dimethacrylate (XV) as the dominant example [7,8]. Neopentylglycol dimetha­crylate (XVI) was first mentioned in a patent assigned to Borden [21]. The use of acrylic or methacrylic acids to improve adhesion to smooth surfaces was mentioned in a patent assigned to Loctite […]

It has been suggested that one of the functions of the saccharin in anaerobic cure is to dissolve metal ions from the surfaces in order to catalyze the decomposition of CHP. X-ray photoelectron spectroscopy of a model anaerobic adhesive cured in contact with a metal surface indicates that trace amounts of metal or metal ions […]

An important factor in the initiation of anaerobic adhesive cure is the redox reaction between a hydroperoxide and transition metals with adjacent oxidation states [10]. Fe2+ + ROOH! Fe3+ + RO • + OH~ Fe3+ + ROOH! Fe2+ + ROO • + H+ In the reactions above, other transition metals will react similarly, and copper […]

Anaerobic adhesives and sealants have been developed primarily in industrial laboratories, and most of the published literature are patents. A number of papers have been published within the last two decades which discuss the reaction mechanisms of anaerobic adhesive cure [10-20]. A. Oxygen Inhibition The polymerization mechanism of anaerobic adhesives is similar to that of […]

A large number of variations are possible for anaerobic curing products, but all will consist of the following components: 1. Monomer. Methacrylate esters are used in almost all anaerobic products. Acrylates, acrylic and methacrylic acids, and few other vinyl polymerizable monomers may be used for special purposes. 2. Initiator. A hydroperoxide (typically, cumene hydroperoxide) is […]