CHAPTER VII. 



CASEIN ADHESIVES AND PUTTIES. 



THE employment of casein as an adhesive substance is of 

 fairly ancient date, though it is only within the past ten to 

 fifteen years that it has received any extensive attention, 

 and been placed on the market under various names, such 

 as casein glue, cold glue, cold-water glue, caseogum, gluten, 

 etc., which are not merely suitable for industrial purposes, 

 but also, and mainly, for replacing glue in the wood- working 

 industries. Nevertheless, though many of these preparations 

 comply with all the requirements of a glue substitute, and 

 possess the additional advantages of being inodorous and 

 ready for immediate use without previous soaking and 

 heating, they have not made any great headway in practice. 

 However, there is very little doubt that the prejudice against 

 them will not continue to exist when their advantages are 

 made fully known to consumers. 



The raw material for these casein adhesives and putties 

 is the fat-free casein obtained from curdled milk and brought 

 into a liquid or pasty form by the aid of chemical agents 

 like the alkaline earths, their salts, ammonia, tungstic salts 

 and water. The products thus formed are ready for use; 

 but analogous products in the form of powder can be pre- 

 pared from casein that has been dried out of contact with 

 air, then ground and brought into contact with the solvent 

 reagents. In general the casein glue ready for use, i.e., 

 mixed with water, has been more successful than the dry 



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