Лако-красочные материалы — производство

It was noted above that, during the second half of the nineteenth century, mixtures of terpene resins (e. g. rosin) and natural rubber were introduced as PSAs, and used initially for the production of adhesive plasters and simple adhesive tapes (see Section 5.1). The mixtures are produced in suitable organic solvents which evaporate after application […]

Dextrin glues are made from starch swollen that has been (but not dissolved) in water. Starch is commercially available in different qualities. At a temperature of 50-70 °C, mixtures of starch and water, with a starch content of 10-20%, will ‘gelatinize’ with a 100-fold increase in volume and a drastic increase in viscosity. Hydration with […]

Casein glues are still used today, in the form of so-called ‘cold glues’, in some sectors of the wood-processing industry. As described above, casein is a phosphoprotein which is insoluble in the purified condition and, in the presence of water, merely swells. Only if alkaline substances such as caustic soda solution are added is casein […]

As mentioned above, the base material of glutine glue is collagen, a high-molecular — weight protein that is insoluble in the unprocessed condition. Depending on its origin, collagen has different mechanical properties: skin collagen is highly elastic, while bone collagen is very hard. In order to obtain water-soluble glutine, calcium hydroxide is added to collagen, […]

The examples discussed above may give the impression that the use ofthese natural adhesives is limited to specialized niche technologies. In the following paragraph however it will be shown, quite on the contrary, that natural adhesives are also suited to large-scale industrial applications, and that there are not always reasons to replace them with synthetic […]

With regards to their chemical structure, the higher-molecular-weight, organic base materials used in natural adhesives can be classified as: • Proteins: elastin, fibronectin, keratin, collagen • Polysaccharides: cellulose, starch, gum arabic • Polyphenols: lignin, urushiol • Lipids: terpenes, terpene resins Proteins represent the most important structural component of living cells in both the animal and […]

5.9.1 Introduction For many years, up until the 1930s, natural inorganic or organic substances were the most important raw materials for the production of adhesives. However, with the emergence of polymer chemistry and its rapid development, they were increasingly replaced by synthetic products. In the history of mankind, there is abundant evidence of humans being […]

Addition silicones for bonding and sealing purposes were developed later than condensation silicones. These modern systems consist of a siloxane with a terminal vinyl group, and a siloxane with a hydrogen atom that is directly bound to the silicon. The exothermic addition reaction is platinum-catalyzed (Figure 5.36) and, when conducted at room temperature, full cure […]

Unlike addition crosslinking, condensation crosslinking of silicones takes place by release of the reaction products. Condensation silicones adhere well to a larger number of substrate surfaces, and the risk of the crosslinking reaction being inhibited is lower when they are used. By splitting off the corresponding alcohol, branched silicones are generated using hydroxyl polysiloxane and […]

Two-part silicone adhesives are known as RTV-2 silicones, and are used for applica­tions where curing takes too long with RTV-1 silicones due to the prevailing conditions of bond-line thickness, temperature and air humidity. Two types of silicone crosslinking have been identified, namely condensation and addition, but neither type requires the presence of moisture.