July i, 1909.] 



THE INDIA RUBBER WORLD 



351 



The Deresination of India-Rubber — III. 



By H. O. Chute. 



UTILIZATION OF EXTHACTED SESINS. 



IN any system of deresinating rubber on a large scale there will 

 be a certain quantity of by-product in the shape of ex- 

 tracted resin, according to the quality of the material 

 treated, and the question of the utilization of the resin appears to 

 be well worth study. 



PoNtiANAK Resin. 



In the case of Pontianak gum ("gutta-jelutong"), the 

 weight of the resin extracted amounts on an average to about 

 three times the amount of merchantable rubber produced, 

 and the possibility of selling the resin at any price approach- 

 ing that to be obtained from the rubber would be of great 

 interest, but at present there seems to be little hope for this. 

 In fact, the outlook for utilization of these resins at any 

 price which will materially lower the cost of producing 

 deresinated rubber is almost blank. The resin extracted from 

 Pontianak resembles in many ways the ordinary rosin or 

 colophony rosin, though it differs in several other re- 

 spects. As extracted from the solvent it usually occurs as 

 a white mass with small grains tending to powder but not 

 of crystalline structure, and it melts above the boiling point 

 of water, and when thoroughly melted and cooled if forms a 

 hard, dark vitreous mass, much resembling the ordinary rosin 

 of lower grades. It differs from rosin, however, in two im- 

 portant particulars: First, it does not unite with alkalies to 

 form soap, and, second, on distillation, it does not yield oils 

 which have the valuable property of hardening with lime. 

 These two defects prevent its use for soapmnking and resin 

 oil distillation, wliich arc the two industries in whicli the most 

 rosin is consumed. 



Rosin is largely used in cheap varnishes, and Pontianak 

 resin has been tried for this purpose, but has the one defect 

 of rosin, in that it cracks under changes of temperature and 

 is also slightly tacky. 



Probably the principal efforts towards using Pontianak 

 resin have been made with a view to substituting it for chicle 

 in the chewing gum industry. In the June issue of The 

 Indi.a Rubber World (page 31) was an article showing how 

 chicle, which is the basis of chewing gum, has steadily risen 

 in consumption until, at the present time, after washing and 

 cleaning the chicle and allowing for shrinkage, it costs the 

 manufacturer about 65 cents per pound when ready for use. 

 Any substitute for this costly material would be gladly wel- 

 comed, but Pontianak resin has several disadvantages. As the 

 resin is produced it is contaminated with crude petroleum 

 oil, which seems present in all Pontianak rubber placed on 

 the market, and the odor of crude oil is most persistent and 

 unpleasant. Another objection is that there are usually to be 

 found in the resin small pieces of rubber which appear as 

 black specks, and also grains of sand. The rubber particles 

 cause the resin to darken when melted, and these have also 

 been objected to by makers of sealing wa.x who have used the 

 resin, as the odor of burning rubber is not pleasant to users 

 of the wax. Probably these impurities can be eliminated by 

 chemical treatment, but at considerable cost. 



Notwithstanding these difficulties Pontianak resin has been 

 used with some success, as one producer claims to have sold 

 400 tons to a single varnish company, and carloads to several 

 others, and the companies who have used it assert that after 

 a year's test they find the varnishes with the resin in them in 

 better condition than those without. 



The following data relating to Pontianak resin are fur- 



nished by one of the large producers to those in the trade 

 who are likely to consume the product; 



Solubility. — Soluble in 3Vj parts of naphtha and in turpentine, linseed 

 oil, and similar solvents about the same. Soluble in boiling alcohol and 

 crystallizes out on cooling. 



.Melting Point. — .•\bout 220 deg. F. 



Aroisliire and light boiling oils (residual naphtha) can be eliminated by 

 heating to 400 deg. F. till froth disappears. 



Hardening. — Will not saponify, so that the lime method will not work. 



Mixing IVitli Other Cunts. — Can be mixed with other varnish gums, 

 waxes, or paraffine in any proportion and dissolves the gelatinous product 

 formed by overheating Chinese wood oil, and with linseed oil gives flexibility 

 and toughness to coating. 



.Solutions. — All solutions give some residue on ageing, leaving 

 solutions bright and clear. A straight resin varnish has a slight tackiness 

 but coatings softened with linseed oil are free from this feature, and 

 the coatings arc inert to chemical action and stand exposure to the weather. 

 It is non-porous and therefore waterproof and materially improves weather- 

 ing qualities of paint and varnish and it has a body which gives great 

 covering power. 



Ol'erheating. — At temperatures of 500 deg. F. and over the resin begins 

 to decompose with formation of acetic acid, but below this temperature it 

 is neutral. 



Color of Solutions. — It is very light in color in solution and is further 

 lightened (while liquid) by sunlight, but long overheating darkens the 

 resin. 



The above data would indicate that Pontianak resin would 

 find some use as an ingredient in paints and varnish, but it 

 is to be remembered that rosin has most of the qualities 

 enumerated above and that at present prices a grade corre- 

 sponding in value can be obtained for 1% cents per pound. 

 At this price, assuming that 10 pounds of raw Pontianak 

 would give one pound of rubber and 3 pounds of resin the 

 value of the resin would be 3J4 cents for each 10 pounds 

 or, say, 1/3 cent per pound on the raw gum, which is not very 

 much on a product worth 5 cents. 



GuAvuLE Resin. 



With regard to the resin from gtiayule rubber the case 

 seems even less promising, so far as getting any price for 

 the resins which will materially add to the profits of the 

 operation of deresination, for only one pound of resin is 

 produced for 3 pounds of crude rubber treated. 



The resin is altogether different from that of Pontianak 

 gum, being black, or at least quite dark, and liquid or tarry at 

 ordinary temperatures and of exceeding stickiness, but it 

 hardens or vulcanizes with sulphur, while the resin of Pon- 

 tianak seems unaffected by sulphur at the ordinary vulcaniz- 

 ing temperature. The data given below are derived froin the 

 same sources as what has been quoted in regard to Pontianak 

 resin: 



Solubility. — Guayule resin is readily soluble in all the solvents of the 

 Pontianak f^nduct and slightly soluble in alcohol. But all the solvents 

 leave a finely divided residue of wood fiber which will settle on standing. 



Qualities. — Its chief characteristic in mixtures is to increase flexibility 

 and elasticity. 



Saponification. — It will readily saponify and can be used as a substi- 

 tute for or to dilute saponifiable oils, such as castor oil. Its soaps of lime, 

 aluminum, sodium, lead, etc.. are of interest but have not yet been 

 investigated. 



The above suinmary of the qualities of guayule resin seem 

 to indicate that perhaps its property of saponifying should 

 be further investigated and inay lead to useful applications 

 and should be further investigated. 



Its exceeding stickiness would indicate that perhaps it 

 would be of value in flypapers, belt dressings and the like, 

 and it will stand exposure to the atmosphere for a remark- 

 ably long time without showing any signs of hardening. 



At present there cannot be said to be any fixed quotation 



