Лако-красочные материалы — производство

The first synthetic thermosets used as adhesives were phenol-formaldehyde resins produced at the end of the nineteenth century, historically linked to Baekeland’s process which attained industrial status at the beginning of the twentieth century [4]. Furanic condensates appeared much later as a result of the marketing of 2. They were first used as foundry binders […]

The relevant properties of furanic compounds covered in this review are summarized in Table 1. The compositions of poly2 and poly3 were studied by several groups [2,3] and shown to have mainly the following structures: Their relative abundance depends, of course, on the conditions used for their syntheses. A typical composition [3] is given in […]

Mohamed Naceur Belgacem and Alessandro Gandini Ecole Frangaise de Papeterie et des Industries Graphiques (INPG), St. Martin d’Heres, France I. INTRODUCTION The dwindling availability of fossil reserves constitutes a driving force towards finding alternative resources which can substitute them, totally or partially, in order to prepare chemicals and materials that are normally produced from petroleum […]

A basic formulation capable of giving more than adequate results is presented here so that a starter in the field can get aquainted with these types of adhesives. The procedure for the preparation of this resin can be modified in many ways by varying catalysts, concentra­tion, molar ratios, and condensation conditions. Phenol, 110 parts by […]

As the cost of cold-setting exterior-grade adhesives based on resorcinol is very high due to the high cost of resorcinol itself, the tendency to decrease the amount of resorcinol while maintaining unaltered the performance of the adhesive, when brought to its ultimate conclusion leads to the concept of exterior cold-setting phenolic adhesives of zero level […]

Recently another step forward has been taken in the formulation of PRF adhesives of lower resorcinol content. Liquid resorcinol or PRF resins appear to be mostly linear [4]. The original concept in ‘‘branching’’ erroneously maintained that if a chemical molecule capable of extensively branching (three or more effective reaction sites with an aldehyde) is used […]

A. Fast-Setting Adhesive for Fingerjointing and Glulam Together with the more traditional fingerjointing adhesives that have just been discussed, a series of ambient-temperature fast-setting separate application systems have also been developed. These eliminate the long delays caused by the use of more conventional PRF adhesives, which require lengthy periods to set. These types of resorcinol […]

A PF resol is prepared which constitutes the resin. Resorcinol chemicals or RF novolaks, in aqueous or water-alcohol solutions, are used as hardeners according to the scheme in Formula 8. A. Adhesive 5: Phenol-Resorcinol-Formaldehyde and Liquid Hardener A PRF similar to adhesive 2 is prepared and a PF resol of the same type as adhesive […]

A urea-formaldehyde resin is prepared and resorcinol is grafted onto it as both terminal units or as middle connecting units leaving each resorcinol to present one or two still reactive sites through which to effect the final cross-linking and hardening of the resin. The schematic reaction is shown in Formula 7. The behavior of this […]

A PF resol is prepared and resorcinol is grafted onto it according to the schematic reaction shown in Formula 6. The resin produced is capable of setting in 2 to 3 h and cures in 16 to 24 h at ambient temperature once paraformaldehyde and wood and nut flour fillers have been added. This is […]