76 



THE INDIA RUBBER WORLD 



[November 1, 1911. 



parts varnish maker's benzin is two-thirds solid, and about 

 four parts of the benzin, gives about one-half solid material. 

 Benzol has better solvent properties. With two parts of Pontia- 

 nak resin to four or five parts of benzol the solutions remain 

 clear. Equal parts of resin and benzol, on the other hand, become 

 solid. Mixtures of solvent naphtha and varnish maker's benzin 

 often have a similar solidifying action. Mixtures of benzol 

 and benzin with the resin are somewhat unstable. Russian tur- 

 pentine has better solvent properties than ordinary spirits of 

 turpentine, but in the course of time, solidification sets in with 

 solutions of moderate concentration. Guayule resin is perma- 

 nently soluble in the solutions mentioned and seems to exert 

 some influence in maintaining the Pontianak resin in solution, 



"The foregoing mixtures, which segregate solid material do 

 not dry properly, especially when exposed in moderately thick 

 films. If a very thin film is allowed to dry, say on a glass 

 plate, it may become hard, but is usually cloudy, or 'frosted.' 

 Thicker films usually behave diiTerently as solidification or separa- 

 tion of the material held in solution in a supersaturated condi- 

 tion is very liable to occur, forming a pasty sticky mass which 

 dries very slowly and apparently never attains any very great 

 degree of hardness. 



"There is great uncertainty respecting the permanency of such 

 solutions in storage. The solidification may occur in a few days 

 or the solutions may retain their mobility and clarity for a long 

 time to finally coagulate and become worthless as finish coating 

 material. The various factors which enter into the phenomena 

 of spontaneous coagulation have not as yet been fully determined 

 by me and I content myself for the present simply with calling 

 attention to these observations. 



"In the preparation of finish coatings, such as paint oils, var- 

 nishes and the like, concentrated solutions of resin are often 

 required. For example, making rosin varnish known as the 

 'gloss oil' type, five or six parts of ordinary rosin are used to 

 four or five parts of benzin. With Pontianak rubber resin, 

 ordinarily such concentrations would be impossible to secure. 



"In the manufacture of varnish from hard resins, it is quite 

 customary to heat such resins to a temperature of 500 to 600 

 degrees F. in order to render them more suitable for combination 

 with oils, etc. But in the case of Pontianak resin, it has been 

 supposed that a temperature of 400 degrees could not be exceeded, 

 owing to the formation of acetic acids and other supposedly in- 

 jurious bodies. I have found, however, that this is not the case, 

 but that it is entirely feasible to heat Pontianak resin to a tem- 

 perature of even 600 degrees, or higher, thereby producing a 

 solution which is readily soluble in ordinary volatile thinners, 

 customarily used in varnish manufacture. In order to obtain 

 such a high degree of solubility, I find that by heating the resin 

 for about an hour at about 600-620 degrees F. gives a loss in 

 weight of about 20 per cent, and suffices to render the product 

 readily soluble in thinning mediums, such as benzol benzin and 

 the like. In fact, by such treatment it becomes possible to make 

 a solution in say benzol for example, of just as high a concen- 

 tration as that obtained in ordinary rosin gloss oil. This is a 

 very important consideration, because a concentrated solution . 

 is ordinarily required in coating materials and the dilute mix- 

 tures obtained by the solutions of the raw Pontianak resin in 

 volatile thinners do not give for many purposes the requisite 

 degree of concentration. Another important advantage is that 

 such concentrated solutions derived from the employment of resin 

 heated to 600 degrees or thereabout as above indicated, is the 

 very noticeable mobility of these solutions. Ordinary gloss oil, 

 containing SO per cent, or 60 per cent, of rosin is usually relatively 

 thick and rather viscous, so that when worked out under the 

 brush, considerable drag is experienced and brush marks often 

 appear. In the present case, it is possible to secure relatively 

 thin solutions of unusually high concentration, which work 

 with very great freedom under the brush. While ordi- 

 nary gloss oil is destroyed in a short time by the action of 



the sun and rain, the Pontianak resin, treated in this manner, 

 shows an unusual degree of resistance to atmospheric influence. 



"Solutions of the resins, suitable as paint vehicles, may be 

 made in the following way : 125 lbs. of Pontianak resin is 

 heated for one hour at about 600 degrees F., giving a loss of 

 about 25 lbs. The molten resin is cooled to about 300 degrees 

 F. and thinned with 90 or 100 lbs. of benzol. Or a mixture of 

 equal parts of benzol and benzin may be used for thinning, like- 

 wise other common solvents, such as turpentine, wood turpentine, 

 texene, solvent naphtha, toluol and the like may be employed, it 

 being possible even with solvents, such as texene, which is not 

 as powerful in its solvent properties as solvent naphtha or benzol, 

 for example, to secure solutions of fairly high concentration. 

 The solutions made in this way may, if desired, be incorporated 

 with drying oils and driers, including, fish, linseed, china wood, 

 corn, and soya bean oils. Also manganese and lead oleate and 

 linoleate and guayule resin may be incorporated, the latter 

 especially if a very high gloss is desired. 



"Instead of heating at 600 degrees for one hour, the resin may 

 be heated at a somewhat lower temperature for a longer period, 

 as for example, at 550 degrees F. for two hours or 500 degrees 

 for four hours. If, however, the resin is not heated above 400 

 degrees F. the desired degree of solubility is not secured, nor 

 the desirable properties of mobility and free operation under the 

 brush. The heat treatment may be somewhat shortened by blow- 

 ing air through the resin, or even by treatment with superheated 

 steam, or inert gases, which tend to accelerate the removal of 

 the undesirable and insoluble constituents, or causes changes in 

 these which brings about the desired properties above mentioned. 



"When run at a temperature of 600 degrees or higher, the 

 resulting solution is somewhat dark in color, and this may be 

 bleached, if desired, by filtration through fullers' earth or bone 

 black, or by treatment with chemical bleaching agents, such as 

 chlorin and its compounds having bleaching properties, sodium 

 peroxid, ozone and the like. 



"Owing to the fact that at temperatures above 400 degrees deep 

 seated changes take place in the resin, rendering it a compound 

 seemingly having almost entirely difTerent properties, it would 

 be expected that organic acids would develop which would give 

 the composition a marked saponification equivalent. I find, how- 

 ever, that this is not the 'case, although if the material is heated 

 at 500 degrees or 600 degrees F. with hydrated lime for a long 

 period, a small quantity of the lime is taken up by the resin 

 apparently, resulting in a product which is slightly harder than 

 the unlimed resin. The changes which take place are, however, 

 so far as can be judged, those of polymerization and depoly- 

 merization, so that the very desirable quality of unsaponifiability 

 may be caused to remain substantially unchanged. 



"The treatment of the resin at high temperature may take 

 place if desired at reduced atmospheric pressure, the temperature 

 and length of heat treatment under such circumstances, depending 

 upon the amount of reduction of atmospheric pressure prevailing. 



The oil secured, for example, by heating the resin at 60 degrees 

 F. for one hour under ordinary atmospheric pressure through 

 thinning with a mixture of equal parts of benzol and benzin 

 after the heat treatment, makes a paint oil or vehicle which may 

 be used as a basis for pigments and colors of all descriptions, 

 and in itself yields a paint oil of surprising durability. Such 

 a product mixed with say soya bean oil in the proportion of two 

 parts of the resin solution to one part of the oil and the addition 

 of a small amount of Japan drier, yields a very useful paint oil, 

 and as stated, other drying oils may be used if desired, wood 

 oil, however, being open to the objection that it tends to oxidize 

 more or less in such solutions, when standing in containers, 

 especially partly filled barrels, etc., and gelatinization brought 

 about by such changes, makes it not as useful as certain other 

 oils mentioned, which are free from this objection, as for ex- 

 ample linseed oil and fish oil. 



"In applying this composition to concrete, for which purpose it 



