Patentecl Nov. 12, 1946 2,411,033 l UNrrsc ¿stars-5s PATENT o'FrlÍcE2,411,033 'PROCESS FOR THE COAGULATION 0F CASTILLOA LATEXv l >'iCîrey Foster ¿Forth Arlington, Va., assigner to United States of America, as represented by the ' Secretary of Agriculture ' Original application August, 31, i 1943, Serial No. 500,649. Divided and this ap v No Drawing. plication November 23, 1945, Serial No. 630,517 3 Claims. (Cl. 260-821) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) l This application is made under the act of March 3, 1883, as amended by the act of April 30, 1928, and the invention herein described, if pat 2 only Within a narrow concentration range and is less satisfactory than the results which can be obtained by additional use of an acid substance. ented, may be manufactured and used by or for With tri-sodium phosphate and sodium carbonate, the Government of the United States of America 5 coagulation is not brought about as easily nor is for governmental purposes without the payment the coagulum as workable as obtained by using an to me of any royalty thereon. This application is a division of copending ap- , alkaline substance and an acid substance or salts. Tri-sodium phosphate and sodium carbonate are plication for patent, Serial No. 500,649, filed probably effective because they are strongly alka August 31, 1943. 1o line salts, and are capable both of dissolving the This invention relates to the coagulation of Castilloa latex which in its natural state is nor- protective proteins and of precipitating the re sulting colloidal systems. ` mally stable when treated With acids, and has The following examples, each employing a among its objects a process for the coagulation sample of 15 cc. of undiluted Castilloa latex, which of such latex in a simple manner. 15 had not been previously treated by “washing” or Hevea rubber latex is readny coagulabie by acid otherwise, are illustrative of the process of coag substances and such coagulation is an essential ulation of this invention. step in most commercial methods of preparing Example I I-Ievea rubber. Similar methods cannot be used with Castilloa latex. Commercial 'development 20 A mixture 0f the Sample 0f 131119K and 1 CC- 0f of casuuoa rubber has been retarded by the dir10 Percent NaOH gave n0 Coagulum in the @01d ficulty and uncertainty of the primitive methods 01' 0n Warming- Addition 0f 1 CC- 0f 18 percent now in use in ooagulating its latex HC1 to the heated mixture immediately produced I have found that Castilloa latex can be coaga» Coagulnln Which Was @Onerent and of good tex ulated by acid substances and salts used for coag- 25 tum 5111111511’ results Were Obtalned by repeat mation of Hex/eau latex, provided the oasmioa ing the Process, except that the beaune Was a0 latoX ¿s mst treated with dilute ammonia, oaus_ tic soda, or other alkaline substances, and in the complished‘after the treatment with the hydroxide and the 3md oaso of aoid Substances suon are used in Sun-j- Instead of using HC1, good results were also ob cient quantity to neutralize the alkaline substance 30 tained by using 1 CC- 0f 10 peI‘Cenlì I‘12504, 2 C0 and coagulate the rubber. Gentle heating is nec0f 10 Percent acefßïc acid’ 0r 1 CC- 0f 10 percent essary to produce rapid and satisfactory coagu1131304- COagU-latlon Was 3150 Produced by “Sing lation and clumping of the rubber, but the heat1% CC- 0f 10_Pe1`0ent formi@ acid’ ‘but the Coagu ing can be at any time during or after addition 111m Was gramy. of the alkaline and acid substances or salts. 35 Example II Although the mechanism of_ the treatment is A mixture of the sample of latex and 1 ca_ of not known, probably 1ts effect 1s to dissolve substances other lthan rubber from the surfaces of the latex partlcles. So long as these substances, 10 no1-Cont NaOH gave no ooagnlum in one cold or on Warming on adding 10 oo_ of 10 percent NaCl’ a ooagulnm Was obtained which was only which are probably proteins, coat .the particles, 40 loosely coherent, A compact, though grainy, they cause the part1cles to be pos1t1vely charged, ooagulum was obtained by substituting 2 oo_ of and therefore, to be uncoagulated by positive ions. 10 percent Cock for tno NaCL Removal of these substances by the alkaline subThe sans mentioned above when used alone did stance does not of itself produce coagulation, benot produce Coagulation cause negative rubber particles remain, which, 45 like Hevea latex particles, are stabilized by alkaExample IH line substances. Like Hevea latex particles, however, they are noW coagulable by acid substances and salts used for coagulation of Hevea latex. A mixture of the sample of latex and 2 cc. of 10 percent NaaPO4 gave on heating a grainy, non coherent coagulum. Addition of 1 cc. of 10 per I have also found that use of certain alkaline 50 cent HC1 and slight boiling produced clumping of substances, including alkaline salts such as trithis coagulum. A mixture of the sample of latex sodium phosphate and sodium carbonate, and and 2 cc. of 10 percent NazCOa gave on heating a even sodium hydroxide and ammonium hydroxloose coagulum. ide, can produce coagulation alone. In the use Heating the untreated latex or boiling it alone of sodium hydroxide, however, coagulation occurs 55 did not produce coagulation. Neither was coagu 2,411,033 3 lation produced by making the latex only slightly alkaline and then slightly acid, using litmus pa pers as indicators, even when followed by long heating. Having thus described the invention, what is C1 claimed is: 1. A process for coagulation of Castilloa latex comprising treating untreated Castilloa latex with dilute NaOH in the ratio of about 15 parts of the latex to one part of the NaOH, and then l0y with an acid substance in suiiicient quantity to neutralize the NaOH and coagulate the rubberl and heating to facilitate coagulation of the rub ber. 4 2. A process for coagulating Castilloa latex comprising treating untreated Castilloa latex with dilute NaOH in the ratio of about 15 parts of the latex to one part of the NaOH and then with about 10 parts of dilute NaCl solution, and heat ing to facilitate coagulation of the rubber. 3. A process for coagulating Castilloa latex comprising treating untreated Castilloa latex with dilute NaOH in the ratio of about 15 parts of the latex to one part of the NaOH and then with about ‘2 parts of dilute CaCl: solution, and heat ing to facilitate coagulation of the rubber. TIREY FOSTER FORD.