CHAPTER XI. 



SUNDRY APPLICATIONS OF CASEIN. 

 USES OF CASEIN IN THE PAPER INDUSTRY. 



AN important part is played by adhesives in the industries 

 wherein paper is employed, both in order to inseparably 

 fasten together individual sheets of paper, convert paper pulp 

 into a mouldable condition, and also for the application of 

 thin layers of colouring matter or other coatings on paper or 

 millboard articles. Such coatings may be either matt or 

 more or less glossy, but in any event must be able to with- 

 stand to a certain extent the influence of moisture. For all 

 these purposes casein is, per se, admirably adapted, since it 

 will stick sheets or bands of paper together and forms thin 

 coatings of considerable elasticity both alone or in association 

 with other substances, colouring matters in particular. When 

 a solution of casein is treated with small quantities of formal- 

 dehyde, and the article coated with the preparation is ex- 

 posed to the air, a number of new products can be obtained. 

 Thus, for instance (by patented processes), we obtain water- 

 proof paper that can be used instead of guttapercha paper, 

 waterproof cardboard boxes and cartridge cases, washable 

 wall papers, washable paper garments, coloured papers, art 

 papers, transfer papers and so on. Utensils, more particu- 

 larly basins, dishes and the like, made of paper pulp or 

 millboard, can be rendered waterproof by treatment with 

 formaldehyde, and used for a variety of purposes, e.g., as 



developing dishes in photography. Similarly, cardboard 



(137) 



