LITERATURE i.
2. 3. 4.
CITED
USSR I n v e n t o r ' s C e r t i f i c a t e 382,672. A. I. Balin, T. N. Veretenova, E. V. Lebedev, et al., N e f t e p e r e r a b . Neftekhim., No. 9, 34 (1974). A. I. Balin, T. N. Veretenova, E . V. Lebedev, et al., N e f t e p e r e r a b . Neftekhim., No. 8, 19 (1974). USSR I n v e n t o r ' s C e r t i f i c a t e 540,862.
DISPERSION
MEDIA
FOR
LUBRICATING
I. V . L e n d ' e l , Yu. L. G, I. C h e r e d n i c h e n k o ,
GREASES
Ishchuk, and V. V. Sinitsyn
UDC 6 6 5 . 7 6 5 - 4 0 4 . 9 : 6 2 0 . 1 9 3
The operating conditions of m o d e r n equipment, p a r t i c u l a r l y t r a n s p o r t vehicles, i m p o s e s e v e r e demands on l u b r i c a n t s , including g r e a s e s . One of the p a r t i c u l a r l y i m p o r t a n t r e q u i r e m e n t s is the ability of the g r e a s e to function o v e r a wide t e m p e r a t u r e range, f r o m - 5 0 to 120~ o r higher. Multipurpose l o w - t e m p e r a t u r e g r e a s e s a r e needed for y e a r - r o u n d o p e r a t i o n of t r a n s p o r t vehicles and o t h e r equipment in connection with the d e v e l o p m e n t of the natural r e s o u r c e s of the F a r North and the construction of m a j o r industrial c o m p l e x e s in t h e s e a r e a s. The selection of the d i s p e r s e phase (thickening agent) and p a r t i c u l a r l y the d i s p e r s i o n m e d i u m for such g r e a s e s is an e x t r e m e l y c o m p l e x p r o b l e m . Lithium s t e a r a t e is a v e r y p r o m i s i n g and c u r r e n t l y approved thickening agent that g i v e s the g r e a s e s good s e r v i c e p r o p e r t i e s o v e r a wide t e m p e r a t u r e range. E i t h e r p e t r o l e u m o r synthetic oils or blends of t h e s e oils m a y be used as the d i s p e r s i o n m e d i a . All such oils m u s t have good l o w - t e m p e r a t u r e p r o p e r t i e s , including a high v i s c o s i t y index, a low v i s c o s i t y at t e m p e r a t u r e s down to -50~C, and a low solid point. At the s a m e t i m e , t h e s e oils m u s t have a sufficiently high flash point and a low volatility at 120-150"C [1]. Also of c o n s i d e r a b l e i m p o r t a n c e a r e such oil c h a r a c t e r i s t i c s as c h e m i c a l stability, lubricity, and polarity (which d e t e r m i n e s the influence of the oil on the s t r u c t u r e f o r m e d by the thickening agent); also, the oils m u s t be r e l a t i v e l y available and r e a s o n a b l y low in cost. T h e s e p r o p e r t i e s a r e all det e r m i n e d by the nature of the oil and by its distillation r a n g e and c h e m i c a l group composition. H e r e we a r e r e p o r t i n g on a study of the f e a t u r e s , advantages, and disadvantages of l o w - p o u r high-V.I. p e t r o l e u m oils [2], oils produced by h y d r o c r a c k i n g and h y d r o i s o m e r i z a t i o n [3, 4], synthetic oils [5, 7], and blends of t h e s e oils, for use as the d i s p e r s i o n m e d i a in m u l t i p u r p o s e l o w - t e m p e r a t u r e g r e a s e s . The basic c h a r a c t e r i s t i c s of t h e s e oils a r e l i s t e d in T a b l e 1. The oil v i s c o s i t y at 50~ was d e t e r m i n e d by the p r o c e d u r e of GOST 3 3 - 6 6 , the v i s c o s i t y a t - 5 0 ~ by CA)ST 7 1 6 3 - 6 3 , the e v a p o r a t i o n in 1 h by GOST 9 5 6 6 - 7 4 , and the solid point by CA)ST ! 5 3 3 - 4 2 . The l o w - t e m p e r a t u r e p r o p e r t i e s of the oils w e r e evaluated on the basis of the v i s c o s i t y at - 50~ and the solid point, and the h i g h - t e m p e r a t u r e s e r v i c e a b i l i t y was judged on the b a s i s of the volatility. The lubricating p r o p e r t i e s of the oils w e r e d e t e r m i n e d in a ChShM-3M f o u r - b a l l friction t e s t e r . Among the p e t r o l e u m oils, the lowest v i s c o s i t i e s at -50~C a r e those of the AU spindle oil, 1-12A oil, and ASV-5 oil. However, the volatility of the f i r s t two oils i s 3 . 5 t i m e s that of the ASV-5 oil. In addition, the AU spindle oil is p o o r in l u b r i c i t y . The SU, S-220, and T B - 2 0 oils a r e low in volatility at 120 and 150~ but a r e high in v i s c o s i t y at - 5 0 ~ so that they can be u s e d only in blends with l o w - v i s c o s i t y oils in p r e p a r i n g the t y p e s of g r e a s e s u n d e r c o n s i d e r a t i o n . The ASV-5 oil, which has a low v i s c o s i t y at - 50~C and a low volatility at 120-150~ should be c o n s i d e r e d as the best of the p e t r o l e u m oils f o r u s e in formulating l o w - t e m p e r a t u r e greases. The next g r o u p of oils investigated, produced by h y d r o c r a c k i n g and h y d r o i s o m e r i z a t i o n , consisted of BMG-8, -11, -14, and -16, obtained by h y d r o c r a c k i n g and h y d r o i s o m e r i z a t i o n of a vacuum distillate f r o m Mangyshlak crude, and BMG-22, obtained by h y d r o c r a c k i n g and h y d r o i s o m e r i z a t i o n of r n i c r o c r y s t a l l i n e wax and s l a c k wax. T h e s e oils w e r e found to typically be l o w e r in volatility than the s t r a i g h t - r u n lube cuts with the s a m e o r even higher v i s c o s i t y . The BMG type oils also have e x t r e m e l y f a v o r a b l e v i s c o s i t y - t e m p e r a t u r e p r o p e r t i e s , with low v i s c o s i t i e s at - 5 0 ~ T h e s e m a t e r i a l s obviously show g r e a t p r o m i s e for use as the d i s p e r s i o n m e d i a in formulating g r e a s e s f o r y e a r - r o u n d s e r v i c e . All-Union S c i e n t i f i c - R e s e a r c h and Design Institute of the P e t r o l e u m Refining and P e t r o c h e m i c a l Industry (VNIIPKneftekhim). T r a n s l a t e d f r o m Khimiya i Tekhnologiya Topliv i Masel, No. 5, pp. 12-15, May, 1980.
308
0009-3092/80/0506-0308507.50
9 1981 Plenum Publishing C o r p o r a t i o n
TA BLE 1 Evaporation
Viscosity 7
Oil o~--tt'3 ~
Temp., ~
in 1 h, ~
Four-ball tests
V.I.
Po
p
}
,t,
8 Petroleum oils AU 1-12A ASV-5 8 -220
14,6 15,2 18,5 55,4 54,6
1-50A
TB -20
135,2
BMG -8 BMG -11 BMG -I4 BMG -16 BMG -22
8,8 11,4 14,0 15,7 22,3
170 260 420 1430 2000 2830
3,7 114,5 3,4 10,0 0,8 3,0 1,3 2,8 0,6 2,2 None 0,5
88 92 96 I00 86 105
--48 --32 --43 --32 --28 --20
170 180 198 190 260 250
200 630 630 630 630 790
1120
1260 1260 1260 1580 1580
12 25 25 26 26 32
560 630
22 24 24 24 25
Oils produced by hydrocracking and hydroisomerization 17 25 95 lI0 170
2,4 1,4 0,8 0,4 0,1
3,6 2,8 2,2 1,9 1,5
130 126 125 120 115
--60 --54 --50 --50 --42
185 190 195 220 230
630 630
1260 1260 1260 1260 1260
120 110 I12 105 108
--50 --32 --57 --43 --60
200 250 210 205 250
560 890 450 790 890
1260 1410 1120 1580 2510
22 35 19 32 42
103 110 102 110 108 t05
--39 --45 --49 --48 --43 --49
200 195 200 205 210 200
790 630 790 630 630 560
1410 1260 1580 1260 1260 1260
30 24 34 25 25 23
630
Synthetic oils M A S -14N M A S -35 Alkylbenzene Polypropylene glycol Pentaeryfhritol ester No. 2
64,4 265,0 96,6 70,7 16,8
18o
2020 115 170 70
e
] 0,1 1,8
I 0,4 1,8 0 4 I 2,7 011 0,4 Oil blends
Asv-5 (8o%)+ MAS -35 (2o%)
ASV-5 (50~o)+ MAS-14N
(50%)
ASV~5 (80~o)+Ester No. 2(20%)] ASV-5 (50%)+ BMG-16 (50%) I
ASV-5 (50%)+BMG-22 (50%) AS(50%)V -5 (50%) + alkylben ze ne
29,4 38,5 17,5 16,0 20,2
42,2
ii00 270 330 125 330 265
0,5 0,7 0,6 0,6 0,5 0,5
1,7 2,8 1,6 2,0 1,8 2,2
* "Generalized wear index," similar to m e a n H e r t z load - T r a n s l a t o r .
All of the synthetic o i l s that w e r e investigated, with the exception of the MAS-35, are low in v i s c o s i t y at s u b f r e e z i n g t e m p e r a t u r e s , low in solid point, and low in volatility, even at 150~ The MAS-35 and the pentaerythritol e s t e r have good lubricating p r o p e r t i e s . H o w e v e r , pentaerythritol e s t e r s have e x t r e m e l y adv e r s e effects on rubber and o t h e r s e a l m a t e r i a l s , and t h e s e e s t e r s , the s a m e as polypropylene g l y c o l s , are hydrolytically unstable [5]. Hence, they are not suitable for u s e as the d i s p e r s i o n m e d i a in g r e a s e s for y e a r round operation of t r a n s p o r t v e h i c l e s . Of c o n s i d e r a b l e i n t e r e s t are the l e s s expensive oils (MAS-14N s y n thetic oil) and a l k y l b e n z e n e s , which are low in volatility and l o w - t e m p e r a t u r e v i s c o s i t y , do not s w e l l rubber, and are hydrolytically stable. It has also been of i n t e r e s t to e x a m i n e blends of the ASV-5 oil with synthetic otis and with oils produced by h y d r o c r a c M n g and h y d r o i s o m e r i z a t i o n . Along with rather low volatility (at 120~ the v i s c o s i t y of t h e s e oils at - 5 0 ~ is quite low. An exception is the blend of the A S V - 5 and MAS-35 oils. The blend of the A S V - 5 and BMG-16 oils gives the l o w e s t v i s c o s i t y at - 5 0 ~ (126 P a . sec) and volatility at 150~ (2% weight l o s s ) . In view of the potential suitability of m o s t of t h e s e o i l s and oil blends in the production of g r e a s e s that can o p e r a t e o v e r a wide t e m p e r a t u r e range, it was found desirable to c o m p a r e the properties of a s e r i e s of g r e a s e s prepared f r o m t h e s e different o i l s . All o f the g r e a s e s a m p l e s w e r e prepared by the s a m e m a n u f a c t u r ing technology [6], thickening the d i s p e r s i o n m e d i a with different amounts of lithium 1 2 - h y d r o x y s t e a r a t e so as to obtain g r e a s e s with approximately the s a m e shear yield s t r e s s at 20~C, about 400 Pa. T h e s e g r e a s e s w e r e tested to determine v i s c o s i t i e s o v e r the range of 0 to - 5 0 ~ in the SOD apparatus (ASTM D 1 0 9 2 - 6 2 ) , s h e a r yield s t r e s s at 20~ (GOST 7 1 4 3 - 7 3 ) , evaporation in 1 h at 120~ (GOST 9 5 6 6 - 74), and penetration (COST 5 3 4 6 - 78). The r e s u l t s of t h e s e t e s t s on the lithium g r e a s e s are presented in Table 2. The dropping points of all of the g r e a s e s a r e in the 190-200~ range, and the alkalinities f r o m 0,.02 to 0.08% by weight, calculated as NaOH. A s would be expected, the l o w e s t v i s c o s i t i e s at l o w t e m p e r a t u r e s (450-
309
TABLE 2 o
tm
Dispersion medium
oi: i P.
Ct~
~ a t
lOsec-1 Pa,sec p g
~r-~
P g
Petroleum oils AU 1-12A ASV-5 S -220 SU TB-20
320 270 285 270 280 260
3,4 3,8 4,0 4,0 4,2 3,8
4,3 3,3 0,8 1,1 0,6 None
48 ll0 85 238 150 240
140 280 270 480 1800 2700
3070 3650 4100
820 1250 1525
Oils produced by hydrocracking and hydroisomerization BMG-8 BMGql BMG-14 BMG-16 8MG-22
9
275 245 250 250 255
3,3 4,2 4,8 5,2 4,4
2,2 1,2 0,8 0,4 0,1
56 85 90 98 102
140 210 250 285 300
450 680 750 835 1300
260 240 250 285 255
3,0 4,7 4,2 3,9 4,6
0,3 None 0,6 0,4 0,1
88 198 106 115 186
230 1810 320 620 670
1500 4250 1650 1850 1900
260 265 255 280 270 250
4,2 4,0 4,3 3,8 4,1 4,4
0,5 0,7 0,6 0,4 0,4 0,5
148
370 270 270 240 370 370
2650 1500 1760 900 1400 1650
Synthetic oils HAS -14N MAS-35 Alkylbenzene (350-500~ cut) Polypropylene glycol Pentaerythritol ester No. 2
1~ 12 Oil blends
ASV-5 ASV-5 ASV-5 ASV-5 ASV-5 ASV-5
(80J0)+Mns-5-35 (2o5~ (50%) + MAS-14N (50%) (80%) +Ester No. 2 (20%) (50~0) + BMG-16 (50%) (50%) + BMG-22 (50%) (50%) + alkylbenzene (50%)
8 7,5 ~5
68 88 133
750 P a 9 s e c ) a r e shown by t h e g r e a s e s f o r m u l a t e d with t h e o i l s h a v i n g t h e l o w e s t v i s c o s i t i e s a t t h e c o r r e s p o n d i n g t e m p e r a t u r e s ( B M G - 8 , B M G - 1 1 , and B M G - 1 4 ) . H o w e v e r , t h e v o l a t i l i t y a t 120~ i s r e l a t i v e l y high f o r t h e g r e a s e f o r m u l a t e d w i t h the B M G - 8 o i l . We c a n n e x t c o n s i d e r a s a s i n g l e g r o u p t h o s e g r e a s e s h a v i n g v i s c o s i t i e s a t - 5 0 r in t h e 750-1600 P a . s e c r a n g e : T h i s g r o u p i n c l u d e s t h e g r e a s e s f o r m u l a t e d w i t h t h e p e t r o l e u m o i l s A U , 1-12A, A S V - 5 , B M G - 1 6 , and B M G - 2 2 , and a l s o t h e s y n t h e t i c o i l M A S - 1 4 N , t h e a l k y l b e n z e n e , and b l e n d s o f t h e s e m a t e r i a l s w i t h t h e A S V - 5 o i l , A l l of t h e s e g r e a s e s , o t h e r t h a n t h o s e f o r m u l a t e d w i t h t h e AU s p i n d l e o i l o r t h e 1-12A o i l , a r e low in v o l a t i l i t y a t 120~ f r o m 0,2 to 0.8%. T h i s m e a n s t h a t a l l o f t h e s e o i l s , o t h e r t h a n the AU and 1-12A, c a n be u s e d a s d i s p e r s i o n m e d i a in p r o d u c i n g m u l t i p u r p o s e l o w - t e m p e r a t u r e g r e a s e s . T h e g r e a s e s f o r m u l a t e d w i t h t h e p o l y p r o p y l e n e g l y c o l , t h e p e n t a e r y t h r i t o l e s t e r N o . 2, o r t h e b l e n d o f t h e A S V - 5 o i l w i t h t h i s e s t e r a r e a c c e p t a b l e in v i s c o s i t y a t - 5 0 ~ (1600-1900 P a " s e c ) and e x t r e m e l y l o w in v o l a t i l i t y a t 120~ (below 0.6%). H o w e v e r , i t s h o u l d be n o t e d t h a t t h e p o l y p r o p y l e n e g l y c o l r e q u i r e d 15% l i t h i u m 1 2 - h y d r o x y s t e a r a t e to p r e p a r e a g r e a s e with a s h e a r y i e l d s t r e s s o f 400 P a , and t h e e s t e r r e q u i r e d 12% o f t h e s o a p , in c o m p a r i s o n with o n l y 6% s o a p r e q u i r e d in t h e A S V - 5 p e t r o l e u m o i l . T h i s d i f f e r e n c e i s e x p l a i n e d by t h e high p o l a r i t y of t h e s y n t h e t i c o i l s , which i n t e r f e r e s w i t h t h e f o r m a t i o n o f the s o a p s t r u c t u r e . B e c a u s e o f t h i s high r e q u i r e m e n t f o r t h i c k e n i n g a g e n t , a l o n g with t h e high c o s t and s h o r t a g e o f e s t e r s and p o l y p r o p y l e n e g l y c o l s , t h e y a r e not a t t r a c t i v e m a t e r i a l s f o r u s e a s d i s p e r s i o n m e d i a in t h e s e g r e a s e s . G r e a s e s p r e p a r e d w i t h t h e r e l a t i v e l y v i s c o u s o i l s S - 2 2 0 , 1-50A, T B - 2 0 , M A S - 3 5 s y n t h e t i c o i l , o r t h e b l e n d of A S V - 5 and M A S - 3 5 do n o t m e e t t h e v i s c o s i t y r e q u i r e m e n t s o f GOST 1 4 8 9 2 - 69, a c c o r d i n g to w h i c h any g r e a s e i n t e n d e d f o r u s e u n d e r t h e c o n d i t i o n s e x i s t i n g in t h e N o r t h m u s t h a v e a v i s c o s i t y at - 5 0 ~ no g r e a t e r t h a n 2000 P a " s e c . T h e s e r e s u l t s have e s t a b l i s h e d a p r o p o r t i o n a l r e l a t i o n s h i p b e t w e e n t h e - 5 0 ~ v i s c o s i t y o f t h e g r e a s e and that of the dispersion medium. As the dispersion medium for general-purpose all-season greases that can f u n c t i o n o v e r a w i d e t e m p e r a t u r e r a n g e , u s e m a y be m a d e of t h e A S V - 5 p e t r o l e u m o i l , o i l s f r o m h y d r o c r a c k i n g a n d h y d r o i s o m e r i z a t i o n w i t h v i s c o s i t i e s a b o v e 14 m m 2 / s e c a t 50~C, t h e M A S - 1 4 N s y n t h e t i c o i l , a l k y l b e n z e n e s , and blends with ASV-5 oil. The optimal dispersion medium for all-season low-temperature greases is the b l e n d o f t h e A S V - 5 and B M G - 1 6 o t i s ; g r e a s e s f o r m u l a t e d w i t h t h i s o i l b l e n d a r e l o w in v i s c o s i t y a t - 5 0 ~ C and in v o l a t i l i t y a t 120~C.
310
LITERATURE 1,
2. 3. 4. 5. 6. 7.
CITED
I. V. Lend'el, Yu. L. Ishchuk, and P. E. Nedbailyuk, in: Material from Conference "Methods for Improving the Quality, Reliability, and Life of Vehicles ~ [in Russian], Znanie, Kiev (1976), pp. 6-7. E. V. Voznesenskaya, V. I. Kutukova, V. M. Shkol'nikov, et al., Tr. Vses. Nauchno-Issled. Inst. Pererab. Nefti, No. 14, 9-15 (1976). V. L. Kazanskii, K. M. Badyshtova, T. N. Shabalina, et al., in: Lubricating Greases, Material from Second All-Union Conference [in Russian], Naukova Durnka, Kiev (1975), pp. 29-31. N. B. Shavolina, V. I. Karzhev, V. Z. Zlotnikov, et al., Khira. Tekhnol. Topl, Masel, No. 5, 6-10 (1965). A. I. Dintses and A. V. Druzhinina, Synthetic Lubricating Oils [in Russian], Gostoptekhizdat, Moscow (1958). I. V. Lend'el, G. L Cherednichenko, V. M. Shkol'nikov, et al., Neftepererab. Neftekhirn. (Naukova Dumka, Kiev), No. 14, 35-40 (1976). V. V. Sinitsyn, Selection and Application of Lubricating Greases [in Russian], Khimiya, Moscow (1974).
311
