Document K65523LreYy2qkQZBvE8xGoYX

Monsanto ( ROM i NA M! ft L A. W. Morgan - DATE. . SUBJECT RE* RENCt August 21, 1978 : Polysulfides/ / TO /*Tw. Touchette 1730 Galt 1730 cc M. W. Farrar R2E C. N. Keeney T. G. Iversen B3NC J. T. Renshaw W. T. Vreeland B3NC J. A. Cannon R. U. DeSchutter B3NA A. J. Balek C. Paton B3NA B. J. Hill G. H. Birum Q2D R. H. Mills Q2D '^ Summary Evaluations of polysulfide sealant formulations show that benzyl phthalates are in the position of performing less well than chlorinated paraffin in some critical tests. Cost parameters favor chlorinated paraffin, particularly when compared to Santicizer 278. Long term viability of our position with benzyl phthalates in polysulfide sealants will probably require development of new blends, new blending and sealant technology, and possibly synthesis of new molecules. Detailed Summary 1) Santicizer 278 is inferior to Cereclor S-52 (chlorinated paraffin, ICI) in fogging to glass. Blending Santicizer 8 with Santicizer 278 reduces fogging but Santicizer 8 does not improve the adhesion of Santicizer 278. 2) In glass adhesion and in aluminum adhesion Santicizer 278 is worse than Santicizer 261. Again, chlorinated paraffin is the best of all materials evaluated. All materials respond to epoxy silane adhesion promoters. No filler effects are seen. Santowax 0 and Montars will increase Santicizer 278 aluminum adhesion but not to the point where it is competitive with chlorinated paraffin. 3) Santicizer 278 is reasonably stable with heat and this stability is also shown by Santicizer 261 and by chlorinated paraffin. Heating any of the plasticizers tends to increase the cure rate slightly. Heating any benzyl phthalate plasticizer with manganese dioxide catalyst will reduce the catalytic efficiency and retard curing of the polysulfide. This does not occur as dramatically with chlorinated paraffins or DUP. Lead dioxide will deactivate when heated with Santicizer 278. This does not occur with Santicizer 261, Santicizer 160, Cereclor S-52 (chlorinated paraffin), or DUP. It has also been shown that alcohols will lower the cure time and reduce adhesion of the systems. Any high alcohol levels in plasticizers are detrimental in this respect. DSW 588366 STLCOPCB4093702 - 2- Tentative Conclusions, Options, Leads, etc. 1) Santicizer 261 seems less reactive to manganese dioxide than Santicizer 278. The switch of the polysulfide industry to manganese dioxide rather than lead dioxide has allowed the use of chlorinated paraffins in a number of applications, and Santicizer 278,'s advantages are limited with manganese dioxide. It seems possible that Santicizer 261 may be the benzyl phthalate of choice for blends. The use of Santicizer 8, Santowax Q, or Montar 9 with Santicizer 261 may indicate a viable blending lead. 2) The cost of chlorinated paraffins indicates that a low cost blend stream for benzyl phthalates may be advantageous. Alkylates as H-230-L seem to be a possibility providing adhesion problems can be solved. These materials blended with Santicizer 261 may be viable candidates and should be screened further. 3) Adhesion promoters include calcium oxide generators, iron halide materials, unsaturated polyesters for cross-linking, anhydrides, sulfonamides, etc. No materials evaluated to date, however, are as efficient as epoxy silene adhesion promotion. This may indicate a need for synthesis to help generate new leads. The material could be reactive with mercaptans, contain methoxy silane groups, be multi functional, or possibly have phosphorus in the backbone. 4) The chlorinated paraffin threat to the benzyl phthalate position seems to be mostly in calcium carbonate filled systems. The black filled system will probably be less threatened. It is recommended that some defensive research be carried out to protect our position in black filled systems, and to maintain our technology level in the use of benzyl phthalates in catalyst dispersions. 5) The loss of adhesion by Santicizer 278 and the surprisingly good performance of chlorinated paraffin is a complex situation. Work has shown that low molecular fragments of polysulfide rubber appear on the surface when rubber is exposed to moist heat or U.V. A chain terminating complex of manganese with the rubber is postulated. One customer has indicated this hypothesis may be valid. The low molecular fragments would be easily solvated by Santicizer 278, increasing moisture pick-up and decreasing adhesion. os* STLCOPCB4093703 -3- Chlorinated paraffin will, however, dehydrohalogenate leaving olefins that can crosslink the rubber thus preventing migration of fragments which may form. Incorporation of low levels of PVC or polybutadiene in Santicizer 278 may improve performance by the same mechanism. 6) It has been learned in discussions with Norton Co. and PRC (see J. H. Orem reports) that the commercial ratio of rubber to plasticizer is nearly 1:1 instead of the 3:1 ratio recommended by Thiokol. This increases the problems possibly dependent on plasticizer but also allows the use of other polymeric blends with benzyl phthalates. Proposed Technical Topics ' 1) Compare Santicizer 261 and Santicizer 278 in blends with Santowax Q, Montar 9, Santicizer 8, etc. 2) Determine properties and suitability of H230L and other alkylates as a blending agent with benzyl phthalates. 3) Determine utility of latent crosslinkers (as PVC, polybutadiene, etc.) with benzyl phthalates. 4) Evaluate new molecules as available, particularly those containing unsaturation or otherwise reactive to the polysulfide resin. Discussion The current threats and questions pertaining to our benzyl phthalate position in polysulfide sealants have been well documented (J. H. Orem). In general the use of manganese dioxide as a catalyst has allowed the use of chlorinated paraffin in what was previously a proprietary benzyl phthalate market. This catalyst, the new coated fillers which compensate for the chlorinated paraffin viscosity variations, and "cleaner" chlorinated paraffins have led to the current situation where chlorinated paraffins are equivalent or better in many tests when compared to Santicizer 278 or Santicizer 261. Table 1 describes recent Monsanto laboratory evaluations. Basically, Table 1 shows that chlorinated paraffin is superior in fogging, adhesion, cure stability, and physicals to Santicizer 278. Considering the wide variation in cost it is apparent why chlorinated paraffins are under evaluation as a Santicizer 278 replacement. It is noteworthy in Table 1, particularly in adhesion, that Santicizer 261 is very close to chlorinated paraffin in performance and is somewhat superior to Santicizer 278 in this effect. OS'*1 \ STLCOPCB4093704 -4- The most critical factors, other than cost, in a polysulfide sealant are adhesion, low moisture vapor transmission, good cure stability, and very low fogging results. Adhesion promoters are conventionally added to improve the adhesion of such systems. In Table 2 A189 (epoxy silanes) were evaluated with chlorinated paraffin and with Santicizer 278. In this evaluation the results were essentially equivalent for Santicizer 278 and for chlorinated paraffins. It was shown that Santolite MHP would not cure with Santicizer 278 with the Inmont manganese dioxide catalyst. However, Santicizer 8 was shown to greatly improve the fog value of Santicizer 278, particularly on long-term aging in the Fadeometer. Further data in Table 2 indicates that Santicizer 8.did not give the hoped for increase in adhesion. This effect of Santicizer 8 in improving the fog value should be investigated further. In Table 3 a number of other materials were evaluated. Montar 9 and Santowax Q blended with Santicizer 278 and Santicizer 261 showed that a slight increase in adhesion can be achieved with Montar 9 or Santowax Q particularly in the case of aluminum. This system should be followed up. H-230L was evaluated with Santicizer 278. Stick times were progressively improved with H-230L but the adhesion fell off precipitiously. This should not be much different than the effects usually found with diluent addition and should be over-ridden by the addition of epoxy silane. This particular system may lead to a blend which may be cost competitive with chlorinated paraffin. The use of Santicizer 261 with H-230L should be evaluated for this type of blend. Montar 9, Santowax 0, Santicizer 8 may be evaluated with a blend of this type to hopefully improve its performance. The second half of Table 3 further indicates that HOE, PBSA, or Texanol will lower the adhesion of Santicizer 278 polysulfide system, up to 50-75%. It also indicates anhydride groups will deactivate the catalyst and prevent cure, which eliminates this potential method of increasing adhesion. Table 4 covers the effect of per se heating on the plasticizer involved. It is seen that benzyl phthalates and chlorinated paraffin readily decrease stick times (cure up the polysulfide faster) after the plasticizers have been heated. In Table 5 the acidity of these systems was measured and it is seen that chlorinated paraffin is stable. Santicizer 160, Santicizer 261, and Santicizer 278 are all relatively low in acidity and seem to be very stable. 0S\N 588369 STLCOPCB4093705 -5- Table 6 is the crux of the technical problem facing us. Here the individual plasticizers (benzyl phthalates, chlorinated paraffins, and DUP) were heated with manganese dioxide and lead dioxide. The resulting systems were decanted and the refractive indicies measured. There were only moderate changes in the refractive index, but severe deactivation of the catalyst occurred. Thus, the stick times of manganese dioxide catalyst with benzyl phthalates are radically changed! DUP shows very little interaction but, as is common for most dialkyl phthalates, gives a very sticky tacky surface. Comment . One of the big problems, with getting up to speed after inactivity in this area for 8 to 9 years is the long evaluation time required for polysulfide sealants. Thus, a sample based on an idea one has today will require 3--5 months before a complete evaluation can be achieved. The technical odds of success are not encouraging and some new technology or innovation is certainly indicated. Defensive effort is certainly warranted to maintain our current business as much as possible. Overall success in regaining market share lost to chlorinated paraffin will require that this program in sealants be continued for at least another year in order to gain enough data so that suitable blends or compounds can be generated. A. W. Morgan /vw DS*M83?o STLCOPCB4093706 TABLE I Thiokol LP-2 Thiokol LP-32 Hakuenka CC Santicizer 278 Santicizer 261 Cereclor S52 _ - Inmont Catalyst Stick time (minutes) Stick time (minutes (after 1 mo. aging) Adhesion to Glass (lbs.) Specular Reflectance Orig. No UV Number Side (1) No UV + Corrora glass (2) . UV Blank side (3) Blank side + Corrora glass (4) 1 2 34 5678 100 --> -- -- -- -- ' - - - - 100 -> 30 - 30 - - - . 30 - - - - 30 - - - 3 0 - -- -- -- 30 -- .-- 30 15 90 115 8 0 90 60 20 10 10 45 80 7 0 90 25 35 25 35 1 0.6 0. 6 0. 8 1.4 1.3 2.0 2. 79 81 82 86 75 86 85 89 81 83 84 89 79 89 88 93 69 81 83 85 82 84 86 85 71 84 86 88 85 88 89 88 115 hrs. 1 2 3 4 233 hrs. 1 2 3 4 334 hrs. 1 2 3 4 Shore A (10 Sec.) Instantaneous 100% Mod . PSI 200% Mod 11 300% Mod II Elongation, % Tensile :PSI Moist UV (failures) 5 day 7 day 12 day 18 day OS 40 37 74 33 72 58 57 OS 37 38 79 34 75 61 59 67 76 68 83 61 75 72 73 67 79 68 88 61 78 74 76 74 80 71 OS 71 89 86 83 74 81 71 OS 72 90 86 85 OS OS ------- > OS OS ---- 73 72 72 83 70 79 90 80 73 72 72 83 70 79 91 80 OS ------- > OS --------> 51 30 29 30 38 19 20 17 52 32 32 32 42 24 24 24 697 407 805 686 1286 563 557 523 863 583 1070 955 1587 724 719 678 981 617 - ' - 1921 853 854 816 598 274 193 205 306 482 621 686 ' 1319 1315 1061 -(Swollen) 80% 10% 80% 20% OK OK OK 985 1802 1021 1188 1283 20% - - 0 - 20% Sticky. 20% (Swollen) 20% 20% 20% .20% 20% 80% (20% ------- DSW 588371 STLCOPCB4093707 Thiokol LP32 Hakuenka CC A 187 A 189 Santicizer 278 Cereclor S 52 Santicizer 8 Santolite MHP Inmont Catalyst . Stick Life (min.) Stick Life (1 mo. min.) Adhesion to glass (lbs.) Adhesion to metal (lbs.) 100% Mod. 200% Mod. 300% Mod. Elongation, % Tensile PSI Shore A 10 sec. Instantaneous Control Specular Reflectance 1) Orig. No UV, Number Side 93 2) No UV, Corrora Glass 97 3) UV, Blank Side 96 4) UV, Blank, Corrora Glass 100 1) 47 Hrs. 2) 3) 4) 1) (94 hrs) 2) 3) 4) 1) 139 hrs. 2) 3) 4) * = broke, 1 = tacky TABLE 2 1 100 40 2 3 -- 2 - ' - - 20 20 - 20 - - --- ------ 45 2 -- - 20 -- .- 2 20 -- 678 --> ---- 2 - 15 20 -5 -- '" -- 15 - 5 15 35 25 2. 2 1. 2 30 25 2. 1 1. 1 35 25 360 330 40 305 30 20 90 90 30 (didn 1 cure 3. 5* 3. 8* 4. 0* 2 . 4* 1.3 - > than tensile of polymer 0. 7 - 796 871 10 96 760 958 1103 993 1396 - 787 1139 - 861 1185 - 780 1092 - 757 954 1088 -- 517 627 218 259 258 223 527 - 1315 28 34 1500 27 35 1448 34 37 1304 30 35 1296 34 37 1144 31 35 1355 29 35 - 89 92 86 94 84 95 93 90 91 94 88 97 86 98 96 92 86 91 89 97 85 96 95 92 88 93 91 99 87 99 99 95 85 90 76 8 5 69 95 94 Fa il 87 92 77 89 71 99 97 87 8 9 87 94 86 98 95 89 91 89 97 87 OS 99 \/ 84 84 66 68 59 93 93 86 86 67 70 60 97 96 83 82 85 91 83 97 94 85 84 86 93 84 OS 98 86 90 53 59 55 85 94 88 92 54 60 56 89 97 89 90 81 85 81 97 97 91 92 82 87 82 OS 100 DSW 588372 STLCOPCB4093708 TABLE 3 Thiokol LP32 Santici-zer' 278 Santicizer 261 Montor 9 Santowax Q H-230-L Xnmont Catalyst Stick Time (min.) Glass Adhesion (lbs.) Aluminum Adhesion (lbs.) Thiokol LP32 Hakuenka CC Santicizer 278 Cereclor 352 Mon tor 9 Santowax Q HOE PBSA A-189 *2% Texanol in Santicizer 278 Thiokol Catalyst Stick Time (min.) Glass Adhesion (lbs.) Aluminum Adhesion (lbs.) 12 3 4 5 6 7 8 9 lUU ----------------27 ` 27 -- 30 25 20 10 27 27 33 33 5 10 20 30 s 105 120 75 60 120 85 80 55 1.2 -1.4 1.0 1.3 1.2 1.8 .9 0 .25 .6 . .6 .5 0.1 0 0 0 TABLE 3A 12 34 5 6 78 inn __ ^ 30 ------------------------------------------------------------------------------------:---------- > 30 30 25 25 . 25 25 30 25 .3 0 11 _1L C D 20 20 15 .4 3.6 .8 .6 (> than polymer) 10 .4 .6 5 .3 .7 30 8 ^48 Hrs. 5 .2 - .1 0 - .3 DSW 588373 STLCOPCB4093709 TABLE 4 ,I Thiokol LP-2 50 S-278 15 S-261 S-160 Cereclor S52 S-278 (72 hrs 100C) S-261 " S-160 " Cereclor S52 23 15 1 45678 15 15 15 15 15 Inxnont Catalyst Stick Life (min) 7.5 ------------------------------------------------------------------------------------------------^ 190 135 190 170 145 110 145 140 DSW 588374 STLCOPCB4093710 TABLE 5 Acidity (meg/100 g) at 100C 0 12 24 4B 72 Cereclor S52 Santicizer 160 Santicizer 261 Santicizer 0.44 0.45 0.45 0.50 0.60 0.90 0.88 0.90 0.90 0.89 0.17 0.23 0.26 0.32 0.32 ' 0.42 0.44 0.40 0.38 0.38 DSW 588375 STLCOPCB4093711 TABLE 6 Aged One Week, 100C Santicizer 278 Santicizer 261 Santicizer 160 Cereclor S52 DUP Manganese Dioxide Lead Dioxide Refractive Index 1 2 3 4 5 6 7 8 9 10 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 1.5161 1.5162 1.5243 1.5244 1.5379 1.5376 1,.5061 1. 5063 1. 4792 1 .4790 Stick Times (In 50 LP-2 , 15 Plasticizer, 7.5 Inmont Catalyst) >24 hr >24 hr >24 hr 335 mini ^24 hr 170 min Sticky to touch. * 275 min 115 min 8 5 min * 80 min DSW 588376 STLCOPCB4093712