Патент USA US2374098код для вставки
v’ A". 17’ ‘UNITED ‘STATES ~4 PATENT 0mm 2,374,091; PRESERVATION 0F RUBBER No Drawing. Application January 14, 1943, ' Serial No. 472,399 18 Claims. (Cl. 260-800) The present invention relates to a method of ' retarding or preventing the deterioration of a isopropyl ketone, methyl isobutyl ketone, benzoyl acetone, hydracetyl acetone, monochloracetone. rubber due to ‘aging or exposure to the atmos phere and to the rubber compositions so ob tained. It has long been known that such de terioration can be greatly retarded by treating the rubber before or after vulcanization with cer dichlor acetone, ' acetonyl acetone, ethylidene acetone, allyl acetone, hydroxy acetone, cyclo hexanone, methyl cyclohexanone and equivalents and analogues thereof. oxidants. One object of this invention issto pro vide a superior class oi antioxidants for a rub-_ ber. ' There ‘is ‘considerable variation in the effec tain substances known as age-resisters or anti tiveness of the new condensation products de pending upon the position and number of the amino groups and the ketone with which they are condensed. It is preferred to employ the con 10. . The antioxidants or age-resisters oi‘ the pres densation products of aliphatic ketones and the amino diarylene compounds of the structure ent invention are obtained by condensing a ketone with an amino substituted diarylene com pound. Inaccordance with this invention it has been discovered that the condensation products of~ketones~and~amizies containing the nucleus R\_-/R , x in which one of the ‘ortho arylene groups repre sented by R'contains a single primary amino sub 20 stituent and where X has the same-signi?cance ‘which nucleus contains at least one primary , amino substituent and where the R’s are ortho arylene groups and X is a nonmetallic divalent bridge forming group, comprise an effective‘ group of antioxidants. Examples oi amines which may be condensed with ketones to form the new anti oxidants comprise the amino diarylene furans as for example amino dibenzo furan, amino ca di as before. Best results are obtained where a single primary amino group 3 position in the nucleus 25V 5 naphtho furan, amino pp dinaphtho furan and is linked in the 2 or ‘ 4 X 4 amino iso dinaphtho furan, the amino diarylene 80 thiophens as for example amino dinaphtho thio phen and amino dibenzo thiophen, the amino ?uorenes as for example amino chryso ?uorene, amino iso naphtha ?uorene, amino picene ?uo rene and its isomers amino an: dinaphtho ?uorene 85 and amino pp dlnaphtho ?uorene, the amino di arylene pyrroles as for example amino dibe'nzo ‘ where x is methylene, oxygen or sulfur. The acetone condensation products ‘of these amines . are equal to the most effective antioxidants known for a rubber. ‘ . The age resisting characteristics of a vulcan ized rubber product can be readily ascertained by subjecting samples oi the _ vulcanized product in a pyrrole (amino carbazole), the amino naphtho bomb to the action oi air or oxygen under ele benzO pyrroles, the amino dinaphtho pyrroles and the amino phenanthro benzo pyrroles. Amines 40 vated temperature and pressure. The aged rubber samples are then examined and tested and the of this class may be prepared by nitrating, pref test data compared with the results obtained on erably mono nitrating, the diarylene compound testing the unaged rubber samples. The ‘de and reducing the nitro group to an amino group. In the case of the pyrrole derivatives the N ni terioration in properties effected as a result of ketone, dimethyl ketone, di n propyl ketone, di centage of their original tensile strength. , As illustrative of the action of the new com the oxidation is indicative of the result that would troso. compound is ?rst prepared and this nitrated' 45 normally be expected of that particular stock followed by removal of the nitroso group in known during actual service. Such a test produces an manner and reduction of the nitro group to an e?ect on a vulcanized rubber stock comparable amino group. All of these reactions are well with that resulting from several years of natural known and understood. aging of the rubber depending upon the conditions Examples of suitable ketones with which the of the test. When subjected to this test the pre amines may be condensed to form the new age ferred class of compounds show a powerful pre resisters comprise acetone, diacetone alcohol, servative eifect and rubber stocks containing the mesityl oxide, phorone, isophorone, methyl ethyl new compounds retain, after aging, a high per ketone, acetophenone, benzophenone, diethyl - 2,874,098 2 pounds but without limiting the invention, rub ber stocks were compounded comprising , Stock A B 0 are only illustrative of the invention and other Parts by Parts by Parts by weight weiaht weight Smoked sheets rubber ............ .. 100 , Benzoyl tbio benzotbiazole Diphenyi guanidine _____ _Acetone-2 amino ?uorene._-.. Acetone-2 amino dibenzo furan 100 100 6 3 5 3 3 2 3 2 5 3 3 2 0. 8 0.8 0. 8 50 50 50 0. 2 0. 2 0. 2 1. 0 __________________ _. ........ -- 1.0 Commercial antioxidant .............................. __ ?exing agent, this shows that the new class of materials combine valuable flex resisting prop erties with their age resisting characteristics and both to a degree found only in the most effective materials known. As mentioned above, the foregoing examples ________ _. condensation products of ketones and amino 'diarylene compounds may be used. Mention may be made of the condensation product of acetone and 9 amino ?uorene and the condensation prod uct of acetone and 2,’? diamino fluoren , however, the age resisting properties of these products were inferior to those of products obtained from mono amines having the amino group linked to one of the arylene radicles. Other examples com 1. 0 prise the condensation product of acetone and the following amines: 3 amino ?uorene, 3 amino The condensation product of‘ acetone and 2 dibenzo furan, 3 amino dibenzo tbiophen, 2 amino amino fiuorene in the A stock was pre'pared by 20 carbazole, 3 amino carbazole, 1,2 diamino fluo passing acetone vapor into the amine at 130° C. rene, 1 amino dibenzo furan, 4 amino dibenzo fu in the presence of a little iodine as catalyst. The ran, 2,7 diamino dibenzo furan, 1,8 diamino di product after recrystallizing from alcohol melted benzo furan, 2,7 diamino dibenzo thiophen, 4 at 158-162° C. The condensation product of ace amino dibenzo thiophen, 1 amino carbazole, 3,6 tone and 2-amino dibenzo furan contained in the 25 diamino carbazole, 2,7 diamino carbazole and 9 B stock was prepared in similar manner. Ace amino carbazole. tone vapor was passed into the amine at 110 Furthermore, the method of condensing the 115° C. in the presence of a. little iodine for about ketone with the amine may vary widely from the 48 hours. The soft resin obtained was heated procedure outlined above. While it has been under 3 mm, pressure to remove any unreacted found that the lower boiling ketones like methyl 30 material but the distillation was stopped when ethyl ketone and acetone react most e?iciently the product began to distill over and the residue by passing the vapor of the ketone into the hot comprising the composite reaction product was amine in the presence of a condensation cata Y incorporated into the rubber stock. The anti lyst, the ketone may be re?uxed or fused with oxidant in the 0 stock is a powerful commercial 35 the amine ‘or heated under a presure'grcater antioxidant and anti-?exing agent of recognized than atmospheric in an autoclave. Suitable con importance prepared by condensing acetone and para amino diphenyl. densing agents include, in addition to iodine, sul furic acid, benzene sulfonic acid, p-toluene sul 'The rubber stocks so compounded were vul fonic acid, bromine and the like. The condensa- ‘ canized in the usual manner by heating in a 40 tions take place with elimination of water and press for diiferent periods of time and samples where the ketone is passed into the reaction mix of the vulcanized products were arti?cially aged ture in the form of vapor, the portion which by heating at 158° F. in, a bomb for 120 hours escapes unreacted carries with it the water lib- under 300 pounds oxygen pressure per square erated in the reaction. The vapor after drying inch. The percentage of the original tensile can then be recirculated through the system. strength retained after aging is set forth in the The products produced are believed to be table below. Table Cure (time in mins.) Tensile retained, quinoline bodies. For example the principal con stituent of the condensation product of acetone and 2 amino ?uorene is believed to possess the 50 structure CH3 per cent ‘ C a N/ \ CH: H but the invention is not limited to any theory of structure and it is quite possible, especially where the amino group is not in the 2 or 3 posi The foregoing data show that the age resisting properties of the preferred class of materials are fully equivalent to those of the established com 60 tion, that other types of compounds are formed. Furthermore, it should be understood that it is unnecessary to isolate pure constituents from the condensation products since the composite mercial antioxidant. The ?ex cracking resistance of'the vulcanized 65 reaction products are eminently satisfactory. Obviously, practice of this invention is not lim rubber products was determined on a ?exing ited to the speci?c compositions given above, such machine as set forth by L. V. Cooper, Analytical compositions being merely illustrative of the Edition of Industrial and Engineering Chemistry, manner of employing the antioxidants or age vol. 2, No. 4, 1930, pages 391-394. All three stocks underwent approximately the same number of 70 resisters of this invention. The antioxidants or age-resistors may be employed in conjunction fiexings before failure. Likewise, after aging seven days in an oven at 70° C., while the total number of ?exings before failure was smaller, all three stocks were approximately equivalent. with other vulcanizing agents than those specifi cally disclosed, for this invention is applicable generally to pure rubber or rubber compositions of the most varied nature. Furthermore, the Since the control stock C contained a well known 75 2mm preferred class of materials may be employed in‘ . conjunction with other accelerators than those speci?cally shown with tion product ofacetone and a primary ‘amine having the structure varying di?erences in . tensile and modulus properties but still exhibiting \ the desirable properties of the‘ class. It is to be understood that the term “treatingf’ : as employed in the appended claims is used in a i ‘ x v ‘. generic sense to include either the incorporating of. the preferred class of materials into the rubber by milling or similar process or-their addition to the rubber latex before its ‘coagulation, or the group' completing a ?ve membered ring said bridging group comprising an ‘element which application thereof to the surface of amass oi’ ' of two being satis?ed by hydrogen.o where X is a nonmetallic divalent bridge forming forms a heat ‘stable hydride, any valences in excess crude or vulcanized rubber." The term 5. vThe ‘method of preserving. a rubber ‘which her” is employed in‘ the claims to de?ne a“asulfur vulcanizable plastic material which possesses comprises treating a-rubber with the condensa tion product of acetone and a primary amine hav high extensibility under load coupled with the property of forcibly retracting to approximately itsoriginal size and shape after the load is-re ing the structure g . ‘ Y 4 moved. Examples of such products are India copolymers of butadiene and styrene and buts vulcanizable I -—NHi 2 x/ diene and acrylic nitrile and other natural or prepared ' y. v x rubber, reclaimed rubber, balata, gutta percha. 20_ synthetically v products ' ‘ where the amino group is in the 2 or 3 position which deteriorate upon aging or exposur‘e'to the atmosphere by absorption of oxygen, whether or 25, and X is an element of group VI of the periodic system oi’ atomic weight less than 50. not admixed with ?llers, pigments or accelerating 6. The method of preserving India rubber agents. “ ~ ' v > ' ' which comprises treating India rubber with the condensation product of acetone and a‘primary The present invention islimited solely by the claims attached hereto as part of the present speci?cation. - a 30 What is claimed is?‘ amine having the structure I ' , V 4 1. The method of preserving a rubber which comprises treating a rubber with the condensa tion product of an aliphatic ketone and a primary amine having the structure ' _ .35 where the- amino group isinthe2or3position ' and X'is of methylene 7. The method of preserving a rubber which where the R's are aiylene groups at least one of which bears a primary amino group and X is a comprises treating a rubber with thecondensa nonmetallic divalent bridge forming group com 40 tion product of acetone and 2 amino ?uorene. pleting a ?ve membered ring said bridging group 8. The method‘ of preserving a rubber which comprising an element which forms a heat stable comprises treating a rubber with theconden'sa-v hydride, any valences in excess of two being tion product of acetone and 2 amino dibenzo satis?ed by hydrogen. 7 . 475 2. The method of preserving a rubber which 9. The ‘method of ‘preserving a rubber which comprises treating a rubber with the condensa- ’ comprises treating a rubber with the condensa tion product of an aliphatic ketone and a primary tion product of acetone and 3 amino dibenzo furan. amine having the structure pyrrole. 60 ‘ ' ' ‘ i - ' 10. The vulcanized rubber product obtained by treating a rubber with the condensation prod uct of an aliphatic ketone and a primary amine where the R’s are phenylene groups at least one I having the structure of which bears a primary amino substituent and X is a nonmetallic divalent bridge forming group 65 completing a ?ve membered ring said bridging group comprising an element which forms a heat where the Rs are aryiene groups at least one of stable hydride, any valences in excess of two which bears a primary amino group and X is a being satis?ed by hydrogen. . nonmetallic divalent bridge forming group com 3. The method‘ of preserving a rubber which comprises treating a rubber with the condensation 60 pleting a ?ve membered ring said bridging group comprising an element which forms a heat stable product of ‘an aliphatic ketone and a primary hydride, any valences in excess of two being satis amine having the structure ?ed by hydrogen. > 11. The vulcanized rubber product obtained by ‘ 65 treating a rubber with the condensation product of an aliphatic-ketone and a primary amine hav ing the structure I ' . where X is a nonmetallic divalent bridge forming X/ ' ' . R\_IR group completing a ?ve membered ring said bridging group comprising an element which 70 where the R's are phenylene groups at least one forms a heat stable hydride, any valences in of which bears a primary amino substituent and excess of two being satis?ed by hydrogen. ‘X is a. nonmetallic divalent bridge forming group 4. The method of preserving a rubber which completing a ?ve membered ring said bridging comprises treating a rubber with the condensa 78 group comprising an element which forms a heat 2,374,098 ' of acetone and a primary amine stable 4. hydride. ~ any gvalenceain excess of two being satisfied; by hydrogen. 12. The vulcanized rubberproduct obtained by having- the struc ‘ ture treating. a rubber with the condensation product or an aliphatic ketone and a primary amine hav- 7 ing the structure ‘ I where the amino group is in the 2 or- 3' position _ 10 and X is an element of group VI of the periodic system of atomic weight less than 50. 15. ' The vulcanized rubber product obtainedby where X is a nonmetallic divalent bridge forming ‘ treating India rubber with the condensation prod group completing» ‘a ?ve membered 1 ring said > uct of acetone and a bridging group comprising ‘an ‘element which v forms a heat stable hydride, any valences in primary amine having the _ structure. excess oftwo being satis?ed by hydrogen. 7 13. The vulcanized rubber product obtained by . treating a rubber with the condensation product of acetone and a primary amine having the struc ture ' ' L ' V _ where the amino group is in the 2 or 3 position ' and X is of methylene. _ , 16. The vulcanized rubber product obtained by treating a rubber with the condensation product of acetone and 2 amino ?uorene. where X is a nonmetailic divalent bridge forming _ group completing, a ?ve membered ring said bridging group comprising an element which ‘forms a heat stable‘ hydride, any valences in excess of‘ two being satis?ed by hydrogen. ‘ , 14. The‘vulcanized rubber product obtained by treating a rubber with the condensation product 17. The vulcanized rubber product obtained by ' treating a rubbeer with the condensation product of acetone and 2 amino dibenzo furan. 18. The vulcanized rubber product obtained by treating a rubber with the condensation product of acetone and 3 amino dibenzo pyrrole. ‘ ' JOSEPH R. INGRAM.