April 1, 1917.] 



THE INDIA RUBBER WORLD 



385 



The Composition of Klingerit Steam Packing, 



IN connection with the article descriptive of the manufacture 

 of high-pressure steam packing on page 322 of the March 1, 

 1917, issue of The India Rubber World, the following an- 

 alysis of the composition of Klingerit by Andre Dubosc in "Le 

 Caoutchouc & !a Gutta-Percha" is of interest. 



Klingerit is a pasteboard of amiantlius (flexible asbestos), 

 formed of a series of thin leaves spread on both sides with an 

 agglutinant having a basis of rubber and balata. These leaves 

 are assembled and when subjected to very powerful pressure 

 in a special calender, give an exceedingly homogeneous paste- 

 board. 



By subjecting the Klingerit, cold, to the action of a suitable 

 inflator, the rubber and balata with which the sides of each 

 leaflet are coated, can be transformed into a non-adhesive jelly 

 wfhich will easily permit the separation, the numbering and the 

 examination of the loose leaves after desiccation in the drying 

 oven at 100 degrees. 



A portion was allowed to swell in a mi.xture of equal parts of 

 sulphuret of carbon and of tetrachloride of carbon. After re- 

 maining in this mixture for four hours, the rubber serving as an 

 agglutinant was completely swollen and it was then easy to 

 separate the sheets which composed the pasteboard. 



In a sheet of Klin.gerit board having a thickness of 3.75 milli- 

 meters, IS leaflets, each of a thickness of 25/100 of a millimeter, 

 were then separated. 



The cardboard being 3.7S millimeters tliick, the composition 



2S 



( X 15 ^ 3.75 mm.) was found to be correct. 



100 



The leaves thus separated were subjected to a microscopic ex- 

 amination ; they consist of a felting of long amianthus fibers 

 mixed with about 2 per cent of (cellulose) organic fibers, very 

 much elongated, hollow and imperceptibly attenuated at both 

 ends, colorable after washing with methylene blue and ruthenium 

 red — these do not color the amianthus — with thick walls limiting 

 a fairly large cavity and of a generally uniform diameter. 



These arc flax fibers mixed with amianthus with a view to giv- 

 ing the thin paper of which the leaflet is constituted, a resistance 

 sufficient to endure the process of coating. 



Each leaflet is covered on both sides with a reddish solution 

 applied with a spreader and composed of a mixture of rubber 

 and balata to which is added a very small quantity of sulphur, and 

 dissolved in a suitable solvent, benzine or gasoline. 



This varnish represents the agglutinant element in the Klin- 

 gerit joint and owing to the way in which it is applied, it is easily 

 understood that its distribution in the mass is perfect and that 

 it insures complete cohesion of the various thin leaflets which 

 compose the pasteboard. This is in the main composed of an 

 alternating series of very thin leaves of amianthus and flax, 

 25/100 millimeter thick, held togethei^ by very thin layers of a 

 mi.xture of rulilier and balata to the number of 30; each layer 

 is about 5/100 millimeter thick. 



Klingerit. as it is put on the market, is not vulcanized, but con- 

 tains a sufficient amount of sulphur to allow the rubber and 

 balata to vulcanize when the joint is exposed to heat while in 

 place. Thus a perfect resistance and tightness of the system is 

 insured for the leaflets of amianthus cannot then be reached by 

 the liquids that would induce physical decomposition in them. 

 The most important element of this cardboard is the amianthus. 



.•\ sample subjected to incineration leaves 80.463 per cent of 

 ash. which cannot be corroded by acids and is composed of large 

 amianthus fibers which preserve their morphological structure 

 entirely. The ash when chemically analyzed, was found to be 

 composed exclusively of the finest commercial quality of long- 

 fiber amianthus. 



In order to estimate the quantity of flax cellulose mixed with 

 the . amianthus fiber we converted this cellulose into acetate of 

 cellulose, subjecting it to the action of acetic anhydride and of 

 glacial acetic acid together with some drops of sulphuric acid, 

 used as a catalyst. The reaction took four hours, the liquid be- 

 ing maintained at 60 degrees. After filtration on glass-silk, the 

 solution of acetate of cellulose formed was precipitated by a 

 great afflux of water. The acetate was separated by filtration 

 on a tared filter, washed until perfect neutralization w'as attained, 

 dried in a sulphuric vacuum and weighed ; from the weight of 

 the acetate of cellulose considered as a triacetate, the cellulose 

 content was deduced as 2.237 per cent. 



The analysis of the agglutinant is more delicate I)ecause it is 



composed of a mixture of rubber and balata which is rather 

 difiicult to separate. 



We have observed that if in such mixtures a solvent composed 

 of freshly distilled sulphuret of carbon and 5 per cent of abso- 

 lute alcohol be used, the rubber dissolves rapidly while the balata 

 remains insoluble ; the reaction must take place in a cold state. 

 By evaporating the solvent in a tared vessel, it is possible, for 

 a given weight, to ascertain the amount of rubber contained. 

 This content has, been found to equal 5.185 per cent. 



Tlie pasteboard resulting from the preceding exhaustion was 

 then treated with chloroform in a warm state in a Soxhlet ap- 

 paratus until the solvent passed without any coloration. 



This exhaustion took 8 hours, tlie first passages being strongly 

 colored violet. 



The chloroform, transferred to a tared vessel, was distilled 

 and the residue of balata which was determined by the usual 

 methods, was weighed after desiccation to constant weight in 

 the sulphuric vacuum. 



The balata content was 11.975 per cent. 



The agglutinant is therefore composed of : 



Balata ... 11.975 percent) 17 i-;n 



Rubber .. 5.185 per cmt]^^-^^^ P^' «"'■ 



The quantity of sulphur was found, according to the Hen- 

 riquez method, by disintegrating the board with smoking nitric 

 acid saturated with bromine. A sulphur content of 0.127 per 

 cent was found. 



This figure is low, but because of the inflation of the amian- 

 thus caused by the nitric acid, it is very difficult to obtain a per- 

 fect disintegration, even if large quantities of nitric acid are em- 

 ployed. Another test made with peroxide of sodium, yielded the 

 higher figure of 0.257 for sulphur, which seems more probable. 



In constructing Klingerit we advise the use of 5 per cent 

 of sulphur in proportion to the quantity of rubber and balata. 



According to these tests the composition of Klingerit resolves 

 itself into : 



Amianthus 80.463 per cent 



Cellulose (flax) 2.237 per cent 



Agglutinant 17.160 per cent | ^"'''f , f '^ P" ""* 



'^ (Balata 11.97o percent 



Sulphur 0.127 per cent 



Water 0.033 per cent 



100 per cent. 



RUBBER IN PLASTIC CEMENTS. 



A RECENT review of plastic cements, in "Metallurgical 

 and Chemical Engineering," collects and classifies several 

 of the more valuable formulas and suggestions, gained both from 

 experience and current literature, regarding this class of adhes- 

 ives. The general methods of plastic cement application, as 

 varied to suit special cases, are stated by the author, J. B. 

 Barnitt, who devotes the following section to rubber : 



Because of its toughness, ela.sticity and resistance to alterative 

 influences, rubber is a very useful cement. 

 As a leather cement : 



(a) Asphalt, 1 part; rosin, 1 part; gutta percha, 4 parts; 

 carbon disulfide, 20 parts. 



As a resistant to acid vapors : 



(b) Rubber, 1 part; linseed oil, 2 parts; fireclay, 3 parts. 

 A plain rubber cement : 



(c) Cut crude rubber in small pieces and then add carbon 

 disulfide or benzol, allowing the rubber to dissolve. 



Corks and wood are made impervious to water by soaking 

 them in the above solution. 



The use of rubber in calking cements in conjunction with 

 pitch is also noted : 



Plastic cements for calking must be both tough and elastic 

 and have the added property of expanding and contracting with 

 the joint to which they arc applied: 



(d) Pitch, 3 parts; shellac, 2 parts; pure crude rubber, 1 part. 



(e) Pitch, 1 part; shellac, 1 part; rubber substitute, 1 part, 

 (d) and (e) arc mixed by melting over a burner. 



