Cold-setting processes

The curing of cold-setting sands is effective at ambient temperature. The process begins when the last component of the formulation has been introduced into the mix. It then continues for a few minutes to several hours, depending on the process, the amoimt of binder and the hardening 

These processes are more often used to make moulds than cores, especially for medium or large 

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The chemistry behind many of these gas-hardened processes is similar to the cold-setting processes. Beeause of the gaseous form of the catalysts, it is sometimes necessary to collect and treat their emissions. 

Emissions for the cold-setting processes can be described as follows ... 

Cold Setting. In this process, also called hot-melt, inks are appHed to a substrate in a molten state and upon cooling form a dry ink film. 

Crosslinking improves resistance to heat, stress cracking and abrasion, and also reduces permanent set after loading, residual monomers and/or oligomers and VOCs (volatile organic compounds). Irradiation is a cold sterilization process. 

The curing time at room temperature under pressure was much longer (8 h) in the cold-setting system than in the particleboard production (Table II). Indeed, the tensile strength could be increased when the particleboard was pressed at room temperature for some hours. However, this procedure is of course not applicable in a technical process. 

With the exception of the early work by Herrick and Conca (95) there has, until recently, been surprisingly little research directed to the use of conifer bark tannins in cold-setting wood-laminating adhesives. Current prices for the resorcinol that generally makes up about 25% of the weight of cold-setting phenolic resins are about 1.80 to 1.85/lb. Therefore, comparatively expensive reactions and processing costs can be economically feasible in the development of these types of... 

The importance of letterpress printing today is very much reduced by the cold-set offset process, whereby most of the newspapers are printed. Conventional newspapers are uncoated papers, based on recovered and deinked printing papers and/ or mechanical pulps. However, a coated surface of such a newspaper or another base paper made from a relatively cheap furnish opens new applications for the cold-set web-offset process with significant improved print quality and cost-performance (Fig. 7.7). 

The advantage of these glues over their gelatin counterparts was that they could be applied cold , i.e. at ambient temperatures. Further, the polypeptide chains in the casein contained bound phosphorous in the form of mono- and di-esters of phosphoric acid as well as pyrophosphates. The di-esters and the pyrophosphates caused a degree of cross-linking to take place within the adhesive during the setting process. 

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