Two POLYMEI IIZERS WITH CONTROL P‘ILNBL, USED IN AMEIRIPOE PRODUCTION
HYCAR OR Properties of Typical Compounds B. S. GARVEY, JR., A. E. JUVE, D. E. SAUSER
AND
The B. F. Goodrich Company, Akron, Ohio
H
YCAR OR is an oil-resistant synthetic rubber produced and sold by the Hydrocarbon Chemical and Rubber Company, which is jointly owned by The B. F. Goodrich Company and the Phillips Petroleum Company. Articles manufactured from Hycar by The B. F. Goodrich Company are sold under the trade name “Ameripol”. The object of this paper is to give a general view of the more important properties of a range of Hycar compounds and to illustrate the methods of compounding used. The recipes mere selected, not to meet any particular specifications, but to include different types of stocks which might have commercial utility.
type. The resinous and tarry softeners used with natural rubber also work well with Hycar OR. I n addition, many of the esters, ethers, and ketones used as lacquer plasticizers are
Recipes and 3Iixing The compounding of Hycar OR differs from that of natural rubber in the use of less sulfur, more accelerator, and more softener. If these differences are borne in mind, experience gained in the compounding of natural rubber is an excellent guide to the compounding of Hycar OR. Accelerators and pigments have approximately the same relative effects. Crude Hycar OR contains 2 per cent phenyl-@-naphthylamine, which is sufficient age resister for most purposes. For heat resistance it is advisable to add five parts of heat-resisting antioxidants such as AgeRite resin D or the ketone-amine 602
Recipes and test data are given for nine typical compounds of Hycar OR. These illustrate the methods of compounding this synthetic rubber and the results to be expected from its use. If specific differences with respect to sulfur, accelerator, and softeners are taken into account, Hycar OR may be compounded and processed m u c h like natural rubber. The vulcanizates have good physical properties in general and exceptionally good resistance to oxygen, heat, and oils.
INDUSTRIAL AND ENGINEERING CHEMISTRY
May, 1941
It is advisable to keep the cooling water on full when mixing batches of Hycar OR because considerable heat is generated and because the best milling temperatures are approximately 120" to 140°F. (49" to 60" C.). While in many cases it is possible to mix as large a batch with Hycar OR as with natural rubber, it is generally advisable to mix somewhat smaller batches, a t least until the operators have gained experience. The compounds reported here were mixed in 25-pound (11.3-kg.) batches on a 60inch (152-om.) mill. The mixing times are given a t the bottom of Table 11.
TABLEI. RECIPES OF COMPOUNDS STUDIED Compound Type of stock
A Tread
B Lowset
Hycar OR Zinc oxide Age resister Csptax" Altaxb Tuadsc D. 0. T.G.d Crude lauric acid Sulfur Channel black Gastex P-33 black Clay Soft coal tar Dibutvl Dhthalate
100.0 6.0
100.0 5.0
1.25
... ... 1.0 ... ...
1.0
... ... 1.6 2.0 ... 50.0 ...
... ...
1.6 1.26 50.0
... ...
E Soft stook
Clay loadme
F
G Soling
100.0 5.0
100.0 5.0
100.0
... 1.5 ... ...
... 1.5
100.0 5.0 6.0 3.0
100.0 5.0
... .*.
... ...
... 3.0
1.5
... ... ... 1.5 ... ... 25.0
... 1.5 ... 60.0
1.6
1.0
...
1oo:o
5.0 ... ... 1.25
... ... 1.5 ... ...
... ...
H
Pure gum
I Fastcuring
100.0 5.0
100.0 6.0
179.5
225.5
177.5
153.0
... ... 1.0 1.0 ... ...
... ... ...
... ... ... ... 20.0 ...
108.0
175.00
76.0 50.0
203.0
... 1.5 ... ... 0.25
... .1*..0
... ... ... ... ... ... ii:0 ... ... ... ... 10.0 ... ... ii.b 3.5 0.0 - ..._ _ 2 0-. 0 _ 20.0 _ _ ... _ - 5_ _ 2 0_. 0 _ ... 162.50
0
C D Heatline resistant hose tube Oaso-
1.25 50.0
I . .
257.75
2-Mercaptobenzothiazole. 3. Mercaptobenzothiaz 1 disulfide. Tetramethylthiuram disulfide. d Di-o-tolylguanike. AND NERVE OF HYCAR COMPOUNDS TABLE 11. PLASTICITY
Compound
A
2-lb. wt. at 100' C. 10-lb. wt. at 35' C. 10-lb wt. at 100' C.
x
4.17 2.49 7.66
B 21.9 16.95 53.3
C
E
F
G
H
I
76.6 74.3 94.9
9.64 9.69 71.2
4.5
1.10 1.65
11.4 7.7 70.6
1.53 2.96 7.5
47 37 9
66.2 41 0
D
Goodrich Plasticity 7.93 5.23 5.66 3.33 61.3 45.3
Plasticity and Nerve
Nerve
of length retained atch time, min. lZemill time, min.
58.2 37 10
64.0 29 9
72 25 7
65.7 27 6
55
34 5
35 61
49 23
0
9
T h e p l a s t i c i t i e s of the mixed stocks were determined on the Goodrich plastometer (6) with a %pound (0.9-kg.) weight a t 100" C.,
TABLE111. FLEXING LIFE OF HYCAROR
breakdown is significant, however, and for subsequent processing it must be done properly. On a 12inch (30.5-cm.) mill this requires 5 to 10 minutes for 200 to 250 grams of Hycar OR, with a tight mill setting. Age resister, accelerator, and small amounts of zinc oxide may be added during the breakdown period. The softeners
cold mill. In&is case sulfur should be added during the remilling.
'' -
2--
/
-
-0
603
-,---e0
MODULUS AT
COMPOUND
0
2--
300%
MODULUS A T 300%
I
f $ \ Id
v
COMPOUND
,
1
1
1
l 30 l 1I0 20
A
--
,,ga--a--s0 9
I
1
I
I
4'5
$0
DO
120
/
l
I
I
I
1'0 2'0 3'0
I
l
4'5
0
910
-
500x
T E N S I L E STRE N t T H WITH ULT E L O N O .
MINUTES AT 310.F.
FIWJRB1. RATEOF CUREFOR COMPOUWDS A , B, 0,AND F
I I O
604
INDUSTRIAL AND E N G I N E E R I N G CHEMISTRY
Vol. 33, No. 5
vulcanized a t 275" F. (135" C.). All of these compounds are flat curing and show little or no decrease in tensile strength with increased time of cure. Overcures are indicated by an increase in modulus and a decrease in elongation. As in the case of natural rubber, there is probably no "best" cure for all-round performance. For most purposes the point on the modulus curve where the slope decreases to a constant or nearly constant value should be chosen. Where low set and low hysteresis are important, a longer cure should be selected. On the other hand, aging and tear are somewhat better for shorter cures.
Properties of Vulcanized Compounds
0 BUREAL. 3 F S T A N C A R D S I WILLIAMS X TACKY
x
IO
FIGURE2. COMPARISON OF COMPOUNDS
perature, and then heated t o about 100" C. for 5 minutes. After cooling, the length, L,is measured. L divided by the circumference of the roll and multiplied by 100 gives the percentage of length retained.
Vulcanization PROCEDURE.In molding and vuIcanizing Hycar OR compounds, the same procedures are used as with natural rubber. In this case the rates of cure were determined on molded strips 4.0 X 0.5 X 0.025 inch (10.2 X 1.3 X 0.06 cm.). The time for optimum cure was selected and adjusted for the thicker test specimens by the usual procedure for natural rubber. RATE. Figures 1 to 4 show the change in modulus, tensile strength, and elongation with time of vulcanization a t 310" F. (154" C.) for eompounds A , B, D,and F . Compound I was
The more important properties of the vulcanized compounds are shown in Figure 2 and in Tables 111, IV, and V. Stress-strain characteristics were determined by A. S. T. M. procedure (3). Hardness was measured by a Shore durometer, type A. Rebound was measured in per cent on a modified Schopper rebound tester. The tear data reported are the average of the figures obtained by the transverse and longitudinal tear of crescent-shaped samples (4). Compression set was measured by both method A and method B of the A. 8.T. M. (2). Rapid flex hysteresis was determined by the method of Lessig (7). Both methods A and B of the A. S. T. M. ( I ) were used to measure abrasion resistance. The flexing tests were run on a modified de Mattia type flex tester with standard dumbbell test specimens a t 100 per cent elongation and 200 flexures per minute. Immersion data were obtained by the method of Garvey (6). The freezing temperatures were determined by a method, to be described in detail later, on pieces of the small tensile strips 1.0 X 0.5 X 0.025 inch. As the temperature is lowered, I i s the temperature a t which the specimen no longer shows rapid, spontaneous recovery. I1 and I11 are the temperatures a t which i t no longer bends under a light load and a heavier load, respectively. IV is the temperature a t which the specimen cracks when bent 90'. TENSILE STRENGTH AND ELONGATION. Maximum tensile strength is obtained with channel black loading (compounds A , D,and I ) . Semireinforcing blacks (compounds B and C), clay (compound F), magnesia, iron oxide, and calcium silicate likewise give compounds with fairly good tensile strength. High tensile strength has not been obtained in pure gum compounds (compound H ) . To obtain low-modulus stocks of good quality, it is necessary to use reinforcing pigments to obtain tensile strength and softeners to lower the modulus. The elongation is good. It is lower with highly loaded stocks
OF SOLVENTS ox HYCAR OR TABLEI V . EFFECT Solvent
A 1.5
Per Cent Volume Change of Compound: C D E F G
B
48-Hour Immersion a t Room Temperature
H 4.5
I
127.4
0.0 104.8
0.0 86.1
3.0 102.4
114.7
0.0 90.7
76.3
209.6
135.4
Carbon tetrachloride 36.8 Acetone 176.0
26.0 151.5
23.4 144.9
36.8 234.5
11.7 191.7
20.8 147.4
25.1 105.1
345.1
64.3
36.8 224.6
Distilled water 0.0 S.A.E.20-Woil0.0 05% kerosene
0.0 -1.5
3.0 0.0
1.5 0.75
0.75 -6.1
0.0 -0.75
0.75 0.0
0.0
0 0
1.5 0.0
0.0
0.0
1.5
-4.5
0.0
0.0
2.2
0.0
0,0
4.5
14.9
18.2
6.1
0.0
4,a 4.5
.$-g$z::Z
:::
+5%bensene0.75
i::
$;:
-6.1
-:.;
3":;
0.0
32:;
lj::
0.0
;:;
48-Hour Immersion at 100° C.
Circo X light oil 9 . 2
"% +5%bsnzene11.6
0 .o 0.0
0.0 0.0
5.3
6.1
-
19.1 -17.4
May, 1941
INDUSTRIAL AND ENGINEERING CHEMISTRY
ON TABLEV. EFFECTOF Low TEMPERATURES HYCAR OR
Freezing Temp., e C., in respect to: I. Spontaneousrecovery 11. Bending (lightload) 111. Bending (heavyload) IV. Brittleness
I. 11. 111. IV.
Spontaneous recovery Bendpg (light load) Bending (heavy load) Brittlenese
-----Compound-A B C 0 -25 -15 -5 -30 -30 -35 -35 -15 -55 -55 -50
D f10 -5
-15 -25
F
G
H
I
-10 -30 -40
+10 -5 -10
-10 -20 -30 -55
+10 -10 -15
-56
-25
605
COMPOUND A
E -30 -50 -65 -55
-40
(compounds C and G) and with higher amounts of sulfur (compound B ) . HARDNESS.The hardness can be varied over a wide range by changing the type and amount of pigment and softener. Increasing the pigment loading gives harder stocks, channel black and Gastex being most effective. Increasing the amount of softener decreases the hardness, but the change depends to a large extent on the type of softener used. The lacquer plasticizers, such as dibutyl phthalate, are most effective. Coal tar and coumarone have much less effect on the hardness of the cured compound. I n many cases large amounts of softener can be used. SCHOPPER REBOUND. Rebound elasticity for the pure gum compound, H , is considerably lower than for rubber. Rebound is decreased by pigment loading (compounds A , D,G, and I ) . It is not much affected by softeners such as coal tar or coumarone but is greatly increased by softeners such as dibutyl phthalate. CRESCENTTEAR. The best tear resistance is obtained with reinforcing pigments. Of the softeners, the resinous type has less adverse effect on tear resistance than does the dibutyl phthalate type. COMPRESSION SET. I n general, these compounds have good compression set characteristics. The lowest set compounds are obtained by the use of dibutyl phthalate as a softener, semireinforcing black as a pigment, and fairly high sulfur (compound B) with a slight overcure. The high set of compound F is due to the clay loading, and that of compound I is probably due to an undercure. HYSTERESIS.Hycar OR compounds have high hysteresis as shown by the AT figures. The lowest hysteresis is obtained with the dibutyl phthalate type of softener and moderate loadings of semireinforcing blacks (compounds B and E ) . ABRASION RESISTANCE.I n general, Hycar OR compounds have good abrasion resistance (Figure 2). It is difficult t o compare the abrasion resistance of a Hycar OR compound with natural rubber or with other compounds of Hycar OR because the abrasion index depends on the test used. FLEXRESISTANCE.The flex resistance (Table 111) varies considerably with the type of compound. The highest number of flexures was obtained with the softest compound, E. The next softest stock, H,also has good flex resistance while the hardest stock, G, is worst. Comparisons of compound C with B and of compound D with A and I indicate that low sulfur is advantageous for flex resistance.
0TENSILE STRENGTH I M W . A T 320% D %ELONG. AT BREAK
6
3:
HARDNESS LQQ
5--
s 4-\
J
g
3-2--
--
I
50--
6
REBOUND
0 TENSILE STRENGTH IMW.AT3OOX b X ELGNG. AT BREAK
HARDNESS
COMPOUND
I=1TENSILE STRENGTH I MOD AT 300 X XELGNG. AT BREAK
f
HARDNESS
FIGURE3. EFFECTOF AGINGON COMPOUNDS A , B, D,
AND
F
INDUSTRIAL AND ENGINEERING CHEMISTRY
606
AMERIPOLARE C C T FROM THE BLOCKA N D P L A C E D ON WASH MILL WHEREMOISTUREIs EXTRACTED ASD IT Is SHEETED INTO THINSHEETS
CHTJNKS O F S Y N T H E T I C A
SOLVENT RESISTAXCE.As shown by pure gum compound H a n d tread type compound A in Table IV, Hycar OR is little affected by aGI;hatic or naphthenic oils, water; or alcohol, It is swelled considerably by aromatic hydrocarbons and by ketones. Carbon tetrachloride has only a small swelling action, but some of the other chlorinated hydrocarbons have B more powerful effect. The extent of swelling in oil is lessened by pigment loading and by the use of extractable softeners. It is thus possible t,o compound stocks which will shrink significantly, will
Vol. 33, No. 5
swell to a moderate extent, or will show almost no change in volume in mineral oils. Where an extractable softener is used, it is advisable to select one which will not have a harmful effect on the oil. COLDRESISTANCE.While Hycar OR compounds become logy a t moderate temperatures (Table V), they maintain their flexibility well at low temperatures and in most cases do not become brittle even a t -50" C. Pure gum compound H and those containing dibutyl phthalate ( B , C, E, and F ) are best in this respect. AGINGAND HEATRESISTANCE. Figure 3 shows the effect of different types of aging conditions on compounds A , B, D , and F. All of them stand up well in the three types of aging test, particularly heat-resistant compound D. The effect of aging is t o decrease the elongation and, to some extent, the tensile strength, and to increase the modulus and hardness. BLoox With the amounts of sulfur normally used with Hycar OR, bloom is not encountered. Accelerators used in high ratio, as in compound D, sometimes bloom. Paraffin will bloom in 1 per cent concentration, stearic acid in 2 per cent, and mineral oil in 3-5 per cent.
Literature Cited (1) Am. SOC.Testing Materials Standards on Rubber Products D394-37T (1939). (2) Ibid,, D395-37T (1939), (3) Ibid., D412-39T (1939). (4) Carpenter, A. W., and Sargisson, Z. E., A. S.T. M. Symposium on Abrasion Testing of Rubber, June 23, 1931.
[z;","a'{*$;s ; ~ ~ ~ ~ ; T ~ ~ . , " , " ~ ~ ENCt, CHBM,,
Anal. Ed., 2, 96 (1930). (7) Lessig, E. T., Ibid., 9, 582 (1937).
Acetone-Butyl Alcohol Fermentation of Waste Sulfite Liquor AVERILL J. WILEY, MARVIN J. JOHNSON, ELIZABETH MCCOY, AND W. H. PETERSON University of Wisconsin, Madison, Wis.
ASTE sulfite liquor from pulp and paper mills presents one of the greatest industrial waste problems in this country. Development of a practical method of disposal is a problem in itself, while the utilization of the potential values contained in this material has been the subject of much research in the past twenty years, here and abroad. Significant commercial and semicommercial methods for the utilization of the ligneous portion of waste sulfite liquor have been developed and are now in production in this country (4,6, 6). While these and other proposed methods of utilizing lignin have not yet reached the point of being adaptable to the industry as a whole, they do give promise of an eventually successful utilization of this major constituent of waste liquor. The utilization of the carbohydrate fraction of these liquors has also received considerable attention. In Sweden and Germany the utilization of the sugars in the pro-
W
duction of industrial alcohol has been extensively developed. There are a number of other possibilities for biological utilization of the large quantities of sugars available in this waste liquor, and the investigation reported in this paper was undertaken with this object in view. German and English patenk (7, IS, 16) have been granted on a process for an acetonebutyl alcohol fermentation of waste sulfite liquor but no detailed study has been reported in the literature. The sugars present in waste sulfite liquor result from the acid hydrolysis of the pentosans and hexosans of the wood. Their quantity and relative composition vary considerably with the type of wood used, method of cooking, and amount of dilution practiced in individual mills. I n a waste liquor with 10 per cent solids, the total reducing sugars (calculated as glucose) range between 1.3 and 2.2 per cent in liquors derived from hemlock or spruce woods; they may approach 3
