April 1949
INDUSTRIAL AND ENGINEERING CHEMISTRY
ance to water extraction, in addition to its excellent low temperature flexibility behavior. The plastics manufacturer was faced with the problem of utilizing the outstanding virtues of Flexol TOF without running into problems of failure in service. Flexol TOF was a major improvement over other usable plasticizers in low temperature flexibility but how widely could it be used? The experiences of the last year have given a partial answer to this problem. Here again a chain Qf events can be cited: 1. The plasticizer manufacturer first must know Flexol TOF and its basic performance characteristics. 2. The sales department in discussing Flexol TOF should disclose all laboratory data that are deemed pertinent to the plastics manufacturer, knowing the range of his customers' products. 3. The plastics manufacturer, being even more familiar with *end use requirements, sets up laboratory development work to take advantage of the merits of Flexol TOF. He would not be likely to use Flexol TOF alone in handbag stock. He knows the resultant highly polished sheeting might be placed on a grand piano-with serious results because of marring. He does find that Flexpl TOF can be >sed with some other plasticizers without causing serious marring. Thus he tries Flexol TOF in mixture with Flexol DOP in such products as upholstery or floor coverings. Plexol TOF lends its excellent low temperature characteristics to the product to a degree dependent on its concentration. Through the judicious use of mixtures of plasticizers, it has $becomepossible to correct individual product deficiencies. Skill in devising such mixtures is only now developing but definite progress has been noted. The future for the user of plasticizers is particularly bright. His wants are better known to research each year. A group of new plasticizers i8 being developed which will compete for the job af plasticizing the resins available and which will be able to perform more satisfactorily in present and future compounds. One of the reasons for this confidenceis the close technical rela$ionship between user and supplier. Through this some suppliera
665
have learned the first big lesson in plasticizer technology. A plasticizer is not classifiable as good or bad. For several reasons the product may be good for one and bad for another. The great and growing diversity of end products together with the expanding skills of the user of plasticizers makes it impossible to generalize on other than specific properties that are measurable. A second lesson in plasticizer technology is gained from the sweat and blood, if not tears, shed in the user's laboratory where new plasticizers are being worked into salable products. This lesson teaches that the greatest progress can be made by,building a product around its principal ingredients. In many cases users have been wont to test a new plasticizer by using it in a current formula. I n all probability there will be reasons to modify both the added ingredients, such as stabilizers, as well as the processing conditions to get the most out of any new plasticizer. Judgment of a new product should be made only after thorough testing. The successful user of plasticizers already knows these lessons. He has learned he must keep an open mind in formulating. If it becomes necessary to make radical changes in formulating and processing to achieve a desired goal of performance, he stands ready to make these changes. He realizes he is living in a world of change-that the properties attained today with present plasticizers no more represent the ultimate than did the automobile tire of the early 1920's. The user believes in cooperating with his suppliers, knowing that his own experiences and those of others can guide research that will give him superior plasticizers in the years to come. The future of the plasticized vinyl resip industry will be controlled by the current attitude of the user of plasticizers. With diligence, hard work, and a forward looking, open, technical approach to its problems, this industry can surpass the most optimistic estimates of its future. R E C E I V July ~ D 28,1948.
PLASTICIZERS FROM OXO ALCOHOLS W. J. SPARKS AND D. W. YOUNG Standard Oil Development Company, Elizabeth,
Information is presented on the chemical and physical properties of new octyl and nonyl alcohols, manufactured by the Oxo reaction: olefins are converted with hydrogen and carbon monoxide, under high pressures in the presence of a cobalt catalyst, to aldehydes. The aldehydes then are hydrogenated to alcohols. In this study Oxo alcoholswere reactedwith phthalic anhydride as well asphosphorus oxychloride to form plasticizers which were tested for purity and then compounded with polyvinyl chloride, vinyl chloride-vinyl acetate (95/5) copolymers, and Buna N. For comparative purposes, to show the effect of the structure of the alcohols on plasticizer performance, tests i n the same elastomers were made with di-2-ethyl hexyl phthalate (DOP), di-n-octyl phthalate (Dinopol), and tri2-ethyl hexyl phosphate (TOF). Results show that the Oxo sctyl alaohol can be a direct replacement for 2-ethyl hexanol. When Oxo octyl alcohol is made into phthalate or phosphate esters, the efficiency and extraction Iosses from synthetic resins are about the same as a commercial di-2-ethyl hexyl phthalate or phosphate. The odor of the new Oxo plasticizers, manufactured by certain procedures, i s less than those produced from 2-ethyl hexanol and G-
N. J.
octyl alcohol, and ultraviolet light resistance is superior. Milling tests indicate that Oxo octyl phosphates flux or solvate high molecular weight vinyl resins a t 300" F. faster than tri-2-ethyl hexyl phosphate. Laboratory tests show that Oxo octyl and Oxo nonyl alcohols can be esterified a t a rapid rate; these new esters are stable, light-colored, high boiling liquids which plasticize synthetic elastomers. In the resin tested Oxo octyl alcohol formulated plasticizers with a relative plasticizer performance slightly better than Oxo nonyl alcohol.
ANY types of synthetic resins and rubbers cannot be used comm;ercially without the addition of a plasticizer. The general function of a plasticizer is to change the physical properties of resins and rubbers so that they can be cast, milled, calendered, molded, or extruded into tough and flexible finished products. Plasticizers may be divided into two main classes, monomeric and polymeric plasticizers. Reed ( 1 ) reported on the plasticization of synthetic elastomers in 1943. However, the main object of this work is to present recent results with high boiling monomeric ester plasticizers formulated in part from new octyl and, nonyl alcohols. The
M
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
666
process used, the Oxo reaction, was developed in Germany; olefins are converted with hydrogen and carbon monoxide, under high pressures in the presence of a cobalt catalyst, to aldehydes. The 5 aldehydes then are TEMPERATURE *C. hydrogenated in a Figure 1. Physical Pro ertier of Ca Oxo separate vessel to Alcohoi alcohols. The Oxo octyl alcohols used in this study were manufactured from a C7 olefin available from refinery streams. Some physical properties of this alcohol are shown in Table I and Figure 1.
TABLE I. PHYSICAL PROPERTIES OF CBOxo ALCOHOL Hydroxyl No. Carbonyl No. Saponi5cation No. Acid No.
408 4 13 0.2
Hydroxyl No. x 100) *lcohoi Purity (Theor. Hydroxyl No. (431)
= 95
A.S.T.M. Distillation
75
181.1 182.2 182.8
183.3 183.8 184.4 185.0 186.1 188.3 202.7 99.0
For the Paracril plasticizer evaluation work the compouuds were varied somewhat. However, the main idea in this part of the work was to formulate a sulfur-cured gasket compound that would be elastic at low temperatures and possess resistance ta A.S.T,M. Fuel No. 2.
~~~
To summarize from chemical reaction knowledge and some of the more accessible physical properties, the Cs Oxo alcohols comprise a mixture of isomers having, on the average, two alkyl side groups along a carbon chain 4 to 6 carbon atoms in length. The Oxo nonyl alcohols used were formed in a pilot plant from diisobutylene. The chemical structures present in this experimental Ce Oxo alcohol may be as follows:
E".
CHs I H
Hac-C--C
I
Parts by Weight a00 3 1.5 50
Vinyl Vinyl stabilizer Stearic. acid Plasticizer
180.0
Final recovery
(a)
mercial plasticizers such as di-%ethyl hexyl phthalate, di-noctyl phthalate, and tri-2-ethyl hexyl phosphate. Most of the work reported in this paper will show that these new C8 Oxo alcohols can be used as a replacement of %ethyl hexanol. When made into phthalate or phosphate plasticizers the efficiency and extraction losses are about the same as a commercial dioctyl phthalate. The odor of the CS Oxo alcohol phthalate is different than the di-2-ethyl hexyl phthalate and the ultraviolet light resistance of resins plasticized with these new esters is superior to present commercial dioctyl phthalate. All results show that the COand CSOxo alcohol esters studied are excellent plasticizers for Vinyl resins and Paracrils. The polyvinyl chloride polymer (Geon 101) chosen for the work was obtained from The B. F. Goodrich Chemical Company and the polyvinyl chloride-vinyl acetate copolymer (Vinylite, VYKW) from the Bakelite Corporation. The dioctyl phthalate (di-2-ethyl hexyl phthalate) and di-n-octyl phthalate (Dinopol) were supplied by Ohio-Apex Inc. Tests for odor, solubility in water and organic solvents, flash point, acid number, carbonyl, acetyl, etc., proved that the experimental Oxo alcohol esters were as pure as the commercial plasticizers evaluated. One physical property that showed some difference with chemical structure was viscosity. As viscosity is of importanw in a plasticizer these data are recorded in Table I1 and Figure 2. The following formulation was used as previous work had indicated that good elastic properties are obtained in this blend (1, 3):
Temp., C. 175.5
5 10 20 30 40 50 60 70 80 90 95
Vol. 41, No. 4
H --C-C-OH
H H H H
CHI
I
1501
I
1
I
I
I
I25
0I
3,5,5-trimethyl-lhexanol
1.
Figure
l
!
I
IO
2.
l
!
l
I5 20 25 TEMPERATURE @ec.
l 30
Kinematic Viscosity Data plasticizers
35
on Phthalate
YH3 (b) Hac-
E"I
CHI CHa (c)
HIC-
r!cH
~
CHo
LI -C-HH LI -C-OH HH CHs
2-isopropyl-3,3-dimethyl-lI butanol
CHI
The synthetic elastomers studied were: Paracril 35 NS 98 and Paracril 26 KS 60. As the Paracril number increases the acrylonitrile in the copolymer increases as follows (within small operating variations): Paracril 26, 28% acrylonitrile, 72% butadiene; Paracril 35, 35% acrylonitrile, 65% butadiene. The IiS indicates that the copolymer contains the nonstaining
2,2,4,4-tetramethyl-Ipentanol I
These CS and CP Oxo alcohols were reacted with phthalic anhydride, as well as phosphorus oxychloride, stripped of excess alcohol, washed, and distilled in the usual manner. The new esters then were evaluated in vinyl resin compounds as well as in Paracril (copolymer of acrylonitrile and butadiene) or nitrile rubber blends. For comparative data and general background, tests were made in the same polymers with well known com-
VISCOSITYDATAON PHTHALATE TABLE11. KIMEMATIC PLASTICIZERS Cs. at Temperature, Sample Dinopol (di-n-ootyl phthalate) Di-2-ethyl hexyl phthalate ~l-C~_Of?-alcohol phthalate bL 00u.11u
Di-Ca Oxo aloohol phthalate CL 560.112
C.
10 65.27 139.5 151.2
20 38.35 70.87 78.17
25 30.20 52.09 56.25
37.78 17.66 26.81 29.34
151.5
76.32
56.46
29.08
INDUSTRIAL AND ENGINEERING CHEMISTRY
April 1949
667
TABLE 111. COMPARISON OF DIOCTYL PHTHALATE PLASTICIZERS IN VINYLCOMPOUNDS tiltoak No. Qeon 101 VYNW Di-Cs Oxo alcohol Phthalate CL 560.112 47-EL-564 Di-Ca Oxo alcohol Pbthalete CL 560.110 47-EL-572 Di-2-ethyl hexyl phthalate Di-n-octyl phthalate (DinaPol) Di-Cs Oxo alcohol Phthalate C L 560.114 47-EL-240 Basio.PbC0, Stearic acid Bpecifio $avity Teneile 1 per8 inch LOO dociu~us persq. in. 2008 modulus: Ib. per sq. in. Ultimate elongation, % Bhore hardness (instantly) Crescent tear a t 85' C.. Ib. per linear in. Tinius Olsen Tour-Marshall stiffness,Ib. per sq. in. 23.89' C. 1.67' C. -12.200 c. -15.00' C. -20.56' C. -23.33' C. Bell Telephone brittle temperature, O C. ECxtrusion rate a t 137.78O C. (80 r.p.m.) 0.400-inch die In. per min. G. per min. Bwell index g. per min./ in. per min. Volume increase after 1 day a t 23.89O C. A B T M FuelNo 1 % A'S'T'M' Fuel No' 2' % A:S:T:M: Oil NO. i, Water, yo Volume increase after 6 days a t 23.89O C. A.S.T.M. Fuel No. 1, % A.S.T.M. Fuel No. 2, % A.S.T.M. Oil No. 3, % Water, % Oven-aged 7 days a t 121.l0 C. Tensile, Ib. per sq. in. Ultimate elongation, % Shore hardness (instantly) Oven-aged 4.5 days at 121.l0 C. Tensile, Ib. per sq. in. ' Ultimate elongation, %
I
8.
.
100
...
...
*..
,..
50
,..
...
50
..
...
,*.
50
...
... ...
,.. *..
...
...
..
...
...
50
... 50
...
...
..
1.5 1.254 2710 1890 2630 240 82
3 1.5 1.255 2580 , 1770 2470 240 82
1.259 2650 1640 2250 230 73
3 1.5 1.252 2450 1490 2120 260 76
1.250 3140 1750 2740 260 78
510
460
430
430
1,620 16.320 49,800 55,800 76,000 110,200
1,890 13,360 45 000 49'500 65'100 96:500
1,890 10 000 16:900 23,300 29,900 51,800
8,000 18.050 52,400 61,100 85,700 118,500
,
-28.89
7
iob
50
3
6
4 100
2 100
.*.
5
3 100
1 LOO
3 1.5
-28.89
-28.89
I
.
.
- 40
127 182
125 171
132 186
127 178
1.43
1.37
1.41
1.40
f3.6 fll.9 -0.3 fO.6
f4.O f7.8 -0.2 f0.6
f3.9 f7.9 -0.3 f0.7
-1.0 f9.0 -0.8 f0.7
-6.1 -7.0 -0.1 +1.7
-8.0 -10.1 fl.O f1.0
-8.5 -10.1 fl.O f0.3
-10.1 -9.1 fO.8 f0.2
4390 10 86
2300 0 73
3590 70
3580 60
t
...
100
50
... ...
8
... 100 ...
9
iob ..I
1..
. . I
...
...
50
,..
.
.
I
50
a
3
3
2930 1850 2890 280 75
1.5 1.256 3020 1780 2780 240 77
1.5 1.255 3030 1720 2800 240 77
1.269 3020 1790 2830
490
490
450
440
46
1,800 16 460
64 800 76:700 125,200
1,830 15,130 52,400 62,400 72,800 116,300
1,480 13,180 44,300 47,100 68,100 94,100
1,800 9,000 18,800 24,900 32,600 57,500
1,820 15,510 52,900 57,200 66 200 L12:300
-28.89
-28.89
3
1.5
57:500
122 189 1.55 f7.1 f9.0 -0.5 +o. 1 -3.0 -10.1 -0.5' f0.4
,
3 1.5
L .256
-28.89
-40
1.5
280
80
-28.89
113 176
130 203
129 193
102 161
1.56
1.56
1.49
1.58
f6.0 f12.0 f0.4 f0. 1
f6.0
f9.2 -0.1 f0.0
f1.4 +3.0 -0.6 -0.5
f7.0 f5.8 f0.8
-0.6 -7.7 +1.7 f0. 1
-2.5 -6.5 f1.0 f2.4
-3.0 -12.8 -0.6 f1.7
-2.0 -10.5 4-0.8 fl.0
-0.5
6120 10 82
4350 20 83
6730 10 71
3390 0 68
6040 10 82
4280 40 86
6380 10 94
4730 40
2940 170
3630 100
2690 20
5050 20
3350 170
5440 20
antioxidant (8567) and the number after NS reports the approximate 100" C., 15-minute Mooney viscosity. The tests carried out on a number of the vinyl compounds and Paracril blends were as follows: 100% modulus, tensile strength, ultimate elongation, extrusion rate, Shore durometer hardness, brittle temperature, low temperature stiffness, specific gravity, heat aging a t 121.1' C., light aging color, and volume increase in A.S.T.M. Reference Fuels No. 1 and 2, A.S.T.M. Oil No. 3, and water.
minimum ram ressure at 138O C., then 10 minutes a t 900 pounds per square incg a t 138' C. The molded slabs were allowed to stand at room temperature for at least 1day before testing. Milling Procedure for Paracril Compounds. The Paracril and other ingredients were weighed out and the materials were blended on a rubber mill at 105" C. The order of mixing was Paracril, stearic acid, ester plasticizer, zinc oxlde, canbon black, sulfur, and benzothiozyl disulfide. Total time to mix was about 8 minutes on the 6 X 12 inch laboratory mill. All of the test compounds that contained Paracril and vinyl, cured as well as uncured, were formulated and molded for test by the procedures given by Young et al. (a,$).
PREPARATION OF SAMPLES Milling Procedure for Resins. The ingredients were weighed out and dry-blended by hand. After blending the dry mixture was heated in a Pyrex beaker with the ester piasticizer, and the blend then waa charged to a 6 X 12 inch laborator rubber mill heated with steam to about 140' to 155' C. TXe resin was fluxed about 2 minutes and allowed to mill with a rolling bank for 5 minutes with occasional cutting. ualitative tests indicated that some vinyl resins and different p asticiaers required some alight variationa in temperature to obtain a good mix in 5 minutes. After mill mixing the batch was sheeted off a t 0.075 to 0.15 inch thickness. Molding Method for Resins. This operation was carried out in ci standard A.S.T.M. four-cavity mold ( D 15-41) yielding slabs 6 X 6 X 0.075 inch. The molding cycle was 10 minutes a t
TEST METHODS
9
Tensile Strength, 100% Modulus, 200% Modulus, and Ultimate Elongation. These tests were made on a Model L-3 Scott tester at 25' C. and 50y0 relative humidity. The rate of jaw separation was 20 inches per minute. For measurement of elongation the specimens were bench marked with a 1-inch die, the grips were adjusted a t zero load 0.75 inch apart, and the elongation was measured by means of a decimal scale held close to the specimen. Shore Durometer Hardness. These values were obtained using the Shore A durometer (A.S.T.M. D 676-44T). Multiple readings were taken on each specimen.
668
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
Vol. 41, No. 4
fourth pass, the tube sections representing 30 seconds of running time were collected and the specimens were cooled for 15 minutes a t 25' C. before their lengths and weights were measured. Volume Increase. These values were obtained in standard laboratory fluids a t 23.8' C. SR-6 OF -4.S.T.M. D 471-46T Reference Fuel No. 2 was formulated from 60% diisobutylene, 20% toluene, 5 % benzene, and 15% xylene. SR-10 or A.S.T.M. Reference Fuel No. 1 is pure diisobutylene. A.S.T.M. Oil No. 3 is a low viscosity index mineral oil with a n aniline point of 70' C, Oven Aging. Heat aging data were determined in a hot air circulating oven, carefully designed to give reproducible results in multiple testing. The specimens aged at 121.1" C. were cut out from molded slabs with die C (A.S.T.M. D 412-41).
Figure 3.
TAE(LE Iv.
Extruded Sections of Vinyl Compounds Given in Table I l l
RESIXBLENDSAFTER 150 HOVRS IN ULTRAVIOLET LIGHT
PHYSIC.4L PROPERTIES O F
Compound No.
RESULTS ON V I N Y L BLENDS Table I11 presents results on Geon 101 as well as Vinylite VYNW blends plasticized with three samples of CS Oxo alcohol phthalate as well as di-2-ethyl hexyl phthalate and di-n-octyl phthalate. From these data the effect of alcohol structure on the relative plasticizer performance in vinyl resins can be determined. Tensile Strength. Results show that higher tensile strength
2
1
COMPARISON OF TRIOCTYL PHOSPHATE PL-4STICIXERS IN S'INYL COhlPOUlvDS
TABLE V. Original properties Tensile, lb. per e q . in. Ultimate elongation, % Shore hardness (instantly)
3020 280 80
3020 240 77
Brittle Temperature. Thc instrument used to determine these values was that described under A.S.T.M. D746-44T. The specimens were allowed to condition 25 minutes in air to reach equilibrium temperature in the bath prior to testing. Stiffness Index. By the use of the Tenius Olsen Tour-llarshal tester (A.S.T.M. D 747-43T) the stiffness index in pounds per square inch was determined on a number of the products. Extrusion Rate. To obtain processing data the No. 1/2 Royle extruder was employed. The equipment was set so as to obtain a constant worm speed of 80 r.p.m. The temperature was held, barrel and head, a t 137.7" C. The machine was fixed with die and pin t o form a tube the dimensions of which were 0.4 inch outside diameter and 0.05 inch wall thickness. To assure constant stock temperature, a given volume (about 150 CC.) of material was cycled four times through the extruder. On the
Compound No. VYKW Tri-Cs Oxo alcohol phosphatp Tri-2-ethyl hexyl phosphate Basic PbCOa Stearic acid Tensile, Ib. per sq. in. 100% modulus, Ib. per sq. in. 2007& modulus lb. per sq. in. Ultimate elongktion, % Shore hardness (instantly) Crescent tear a t 25O C., Ib. per linear in Tinius Olsen Tour-Marshall stiffness. lb. per sq. in 23.89O C . 1 . 6 7 O C. -12.220 c. -15.00' C. Bell Telephone brittle temperature, C. Extrusion rate at 137.78O C. (80 r.p.m.) 0.400 inch-die Index per min. Grams per min. Swell index
1
2
100 60
100
...
3 1 5 3000 1250 2100 290 78 460
50 3 15 2660 1310 2140 260 79 410
2000 7100 12000 17100 -62.22
1680 6000 13000 16200 -62.22
88 133 1.51
88 I31 1.47
f4.0
+4.r
+5.0 f1.0
4-5.0 -1-1 1
-1.0 Volume increase after 8 days a t 23.89' C 4.3.T.M. Fuel No. 1, % A.S.T.M. Fuel No. 2, 7% A.S.T.M. Oil No. 3, % Water. % Oven-ased 3 daye a t 121.11° C. Tensile, lb. per sq. in. Ultimate elongation, % Shore hardeness (instantly) Oven-aged 7 days a t 121.11' C . Tensile, Ib. per sq. in Ultimate elongation, % Shore hardness (instantly)
...
-6.0 4-7.8 -1.4 -2.7
-0
w
-5.4 +8.0 -1.6
-2.1
3380 180 87
3100 170 89
348
3620 6lJ 91
50 90
PLASTICIZER TABLIE VI. Di-C9 Oxo ALCOHOLPHTHALATE IN VINYL COXPOUNDf3 Stock No.
vvun-
VYKW
Basic PhCos Stearic acid Di-2-ethylhexrl phthalate
Figure
4.
100 3 1.5
50.0
VYXW Besic PKo3 Stearic acid Cs Oxo alcohol phthalate
Ultraviolet Light Stability of Hour Test)
100 3 1.5 50.0
VYNW Blends (150-
Paracril 35 NE Physical properties Specific gravity Tensile lb. per sq. in. 100% Aodulus, Ib. per sq. in. 200% modulus, lb. per sq. in. Ultimate elongation 7% Bell Telephone bridle temperature, C. (A.S.T.M. D 746-44T) Crescent tear a t 2j0 C., Ib. per linear in Shore hardness (instantly)
1 100
2 100
1.243 2920 2100 2860 220
1,168
-23.3 510
- 40
87
1050 640
1040 480 270
67
. .
669
INDUSTRIAL AND ENGINEERING CHEMISTRY
April 1949
blends. Swell index values (grams per minute/ inches per minute) for the compounds are approximately the same. In Geon 101 the ester 6 plasticizers gave products with a swell index of 75 1.37 to 1.43 and in Vinylite VYNW the swell index ' 3 was found to be 1.49 to 1.58. 5 Volume Increase. The test results for 1 and 6 1.5 1.5 days a t room temperature in the several fluids show that the chemical resistance or solubility be... havior for the plasticized resins is about the same. 40 100 Here the structure of the Ca alcohol phthalate 2 5 ester is not of great importance. Oven-Aging. A study of the heat agiqg data will 1.368 show that the di-n-octyl phthalate is less volatile 1440 from Geon 101 and Vinylite VYNW than di-2380 ethyl hexyl phthalate or the C8 Oxo alcohol 700 phthalate. In the 4.5-day test a t 121.1" C. compounds 4 and 8 in Table I11 had an ultimate 940 elongation to break of 170%; all other blends 590 had an elongation of only 20 to 70% The com62 pounds formed with di-2-ethyl hexyl phthalate had the same heat aging properties as those formed 19.4 with the Cs Oxo alcohol phthalate. Light Aging. In the light aging study 6 X 6 X 0.075 inch pressed slabs were placed in the F a d s omekr (ultraviolet light) at 51.6" C. Results are 18.9 recorded in Table IV. Observations indicate that -46.66 the blends plasticized with the Cs Oxo alcohol phthalate show less color change than the resins plasticized with di-2-ethyl hexyl phthalate or di-n-octyl phthalate. Figure 4 shows the light aging results. The Vinylite VYNW-di-%ethyl he@ phthalate blends show after 150 hours in ultraviolet light a
OF DIOCTYL PHTHALATE PLASTICIZERS IN TABLEVII. COMPARISON PARACRIL COMPOUNDS
Stock No. 1 Paracril 26NS60 100 Zinc oxide 5 Stearic acid 1 Carbon black (Thermax) 150 Benzothiazyl disulfide 1 Sulfur 1.5 Di-2-ethyl hexyl phthalate 40 Di-Cs Oxo alcohol phthalate ... VYNW ... Litharge Physical properties for cure time, 30 min. a t 141.6' C. Specific ravity 1,309 Tensile, fb.per sq.Ib. in. 1220 100% modulus, per sq. in. 100 200'3?~ modulus, lb. 200 per sq. in. 300% modulus, lb. per sq. in. 420 Ultimate elongation, % 790 Shore hardness (instantly) 41 V o 1 u m e increase after 1 d&y a t 23.89O C. (A.S. T.M. Fuel No. 2), 29.6 % V o 1 u m 6 increase aftar 6 days at 23.89' C. (A.S. T.M. Fuel No. 21, % 27.8 Bell brittle Telephone temperature, C. -51 11
...
2 100
3 75
4
..
75
5 75
5 1
1
'1'
' 3
150 1 1.5
150 1 1.5
150 1 1.5
5 1.5 1.5
...
40
...
40
... ...
25 2.6
40 25 2.5
1.306 1310 100
1.162 2110 570
1.161 2220 630
240
1020
1380
880
520
1570
1720
920
820
380
410
570
42
64
64
60
28.0
33.2
34.5
18.9
26.0
25.0
26.7
18.8
40
-51.11
-51.11
-51.11
io0
2.5
1.367 1340 320
-45.56
values were obtained in the Vinylite VYNW blends than in the Geon 101 blends. The dioctyl phthalate plasticizers studied all gave about the same tensile values in the same base resin. * 100% Modulus. The modulus values obtained TABLE VIII. COMPARISON OF TRIOCTYL PHOSPHATE PLASTICIZERS IN show that di-n-octyl phthalate imparts a slightly PARACRIL COMPOUNDS lower modulus than the branched CS alcohol No. 1 2 3 4 5 6 75 phthalate plasticizer. This effect was more proParacri1 26N860 75 75 .,. 75 ... ... . . 7.5 75 ... nounced in the case of the Geon 101 blends ~~~~$la3ffs9o 2 2 2 2 1 1 Carbon black (Ther(stock 4, Table 111). max) 5 5 5 5 150 150 Shore Durometer, Ultimate Elongation, and Bensothiaryl &sulfide 1, 1.5 1.5 1.5 1 1 Crescent Tear. The values obtained in these tests ethyl hexyl phos1.5 1.6 1.5 1.6 1.5 1.5 show that the dioctyl phthalates plasticize the phate 40 ... 40 ... 40 ... phosphate vinyl compounds to about the same degree of Tri-Cc Oxo 40 ... 40 100 25 25 VYNW 100 ' 100 40 100' elasticity. Litharge 2.5 2.5 2.5 2.5 2.5 2.5 Stiffness Values. In this test the structure physical properties for cure time 30 of the alcohol appears to be important. For exmin. a t 141:6O C. ample, a t -23.3' C. the di-n-octyl phthalateSpecific ravity 1.146 1.144 1 154 1.155 1.330 1.332 Tensile, &. per sq. in. 1800 1770 2290 2270 1390 1440 vinyl blends have a stiffness value of 51,800 100% modulus, lb. per sq. in. 670 670 420 400 520 540 pounds per square inch in Geon 101 and 57,500 200% mqdulus, lb. pounds per square inch in Vinylite VYNW whereas per sq. in. 1450 1480 1010 980 1100 1130 300% mqdulus, lb. the di-2-ethyl hexyl phthalate and CSOxo alcohol per sq. in. ... . . 1610 1550 1320 1310 Ultimate elongation, phthalate resin blends have a stiffness value of % 270 280 390 420 290 330 Shore hardness (inabout 94,100 to 118,500 pounds per square inch. 60 59 56 55 59 57 stantly) However, a t 23.89' C. the stiffness values for all Crescent tear at 25' C., lb. per sq. in. 180 190 200 210 200 2101 the blends in Table I11 are about the same. These V o 1 u m e increase stiffness values correlate well with the viscosity after 1 day a t 23.80' C. (A.S. property of the esters (Table 11). T.M. Fuel No. 2), % 28.2 27.2 5.66 5.42 16.7 16.0 Brittle Temperature. Limited results show that V o 1u m e increase the brittle temperatures, t o break, follow the stiffafter 6 days a t 23.80' C. ( A S . ness values-for example, the di-n-octyl phthalate T.M. Fuel No. 2), % 20.9 20.9 17.2 18.6 14.8 14.3 resin blends have a break point of -40' C. V o 1u m e increase and the substituted or branched CSalcohol phthalafter 12 days a t 23.89' C. (A.S. ate resin blends have a break point of -28.8" C. T.M. Fuel No. 2), % 19.0 18.8 9.8 10.8 11.2 11.2 Extrusion Rate. Results on extrusion are shown Bell Telephone brittle temperature, in Table I11 and Figure 3. Figure 3 shows the exc. -62.2 -56.6 -66.6 -56.6 -56.6 -56.6 cellent surface smoothness for all the test resin
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INDUSTRIAL AND ENGINEERING CHEMISTRY
large number of brown spots whereas the Vinylite VYNW-di-Ca Oxo alcohol phthalate blend is almost free of these spots and also shows little color change. This advantage was not confirmed in Florida exposure tests. Table V presents results on Vinylite VYNW plasticized with bri-C8 Oxo alcohol phosphate and tri-%ethyl hexyl phosphate. The results show that these two plasticizers are equal in plasticizer performance at a concentration of 50 parts of ester per 100 parts Vinylite VYKW. These blends have good tensile values, good elongation, and interesting processing properties. Laboratory studies proved that the C8 Oxo alcohol phosphate formed a flux on a mill with Vinylite VYNW a t 150" C. in 2 minutes while the tri-%ethyl hexyl phosphate required a temperature of 160' C. to obtain a flux in 2 minutes. These plasticizers are excellent in their low temperature properties-for example, at -15' C. the blends in Table V have a stiffness of 16,200 and 17,100 pounds per square inch and a break point of -62.2'C. Table VI gives the results obtained with a Vinylite VYNW blend and a VYPTW-Paracril 35 NS 90 blend plasticized with Oxo nonyl alcohol phthalate. A comparison of Tables I11 and V I indicates that the CS Oxo alcohol phthalate and the CS Oxo alcohol phthalate are about equal in these compounds in plascicization efficiency. Only in the brittle point test is the CS Oxo alcohol phthalate better than the CSalcohol ester. However, in general, when other compounds are evaluated, the trade rates Cp Oxo alcohol phthalate as 10% less efficient than the CS Oxo alcohol phthalate.
Vol. 41, No. 4
RESULTS ON P A R A C R I L C O M P O U N D S Tables VI1 and VI11 give results on Paracril blends plasticized with dioctyl phthalate, both C8 Oxo alcohol phthalate and di-2-ethyl hexyl phthalate, as well as the phosphate esters of these alcohols. These data show, based on tensile, 1 0 0 ~ o modulus, ultimate elongation, crescent tear, brittleness, etc., that the plasticizers used impart the same physical properties to the same base compound. Results in Paracril blends show that the structure of the octyl alcohol phthalate and phosphate to be of minor importance as reflected in the check physical properties of the final cured blends. The tensile, 100% modulus, and elongation values obtained on the blends show differences for the test ester plasticizers that the authors believe are less than the over-all accuracy of the test methods. ACKNOWLEDGMENT The advice, encouragement, and assistance of A. Voorhies, Jr.. J. J. Owen, C. E. Rlorrell, B. M. Vanderbilt, L. A. Wlikeska, B. E Hudson, Jr., and P. V. Smith, Jr. during the course of this work are greatly appreciated, LITERATURE CITED (1) Reed, M. C., ISD. ENG.CHEM.,35, 896 (1943). (2) Y o u n g , B. W., B u r k l y , D. J., Newberg, R. G., and T u r n e r , L. B., Ibid., 41,401(1949). (3) Y o u n g , D. W., Newbwg, R G , and Howlett, R. M., Ibid.. 39 1446-52 (1947). RECEIVEDJuly 8, 1948.
LAVERNE E. CHEYNEY' Battelle Memorial Institute, Columbus, O h i o
Natural and synthetic rubbers may be grouped into two broad classes-polar and nonpolar. Dipole linkages are involved in the plasticization of the polar group, hence they possess certain resemblances to the polar thermoplastics in this respect. Plasticizers are employed with such polymers for two general purposes: increasing plasticity of the uncured rubber; and increasing flexibility OP corresponding effects in the cured material. Plasticization of the polar rubbers is a complex problem because of: structural variations inherent in diene polymers and copolymers; the vulcanization process; and effects of other
additives-for example, carbon black. Available data are extremely confusing because of these factors and the faci that much of the information reported is meager. Many of the materials which have been employed may be grouped into a few broad chemical classes. The effects of these vary widely among a given class because of structural variations and differences in physical properties. It is possible to generalize concerning a few- types of effects, but more and better data are required before an adequate picture of the plasticization of the polar synthetic rubbers will be available.
N E of the most useful methods of compounding natural or
Commercial materials of this general type were identified for many years merely as softeners. Many of the products employed in the rubber industry were complex chemical mixtures, often of varying composition. Until the advent of neoprene synthetic rubber, there was little need for softeners or plasticizers, as they began to be known, which would be especially s u i t a h l ~for URC with a particular polymer. The development of plasticizers, particularly the ester typeu, for use with the newer thermoplastics has taken place largely within the past 10 years. The commercial application of several types of synthetic rubbers of varying chemical structure and of specific physical and chemical properties has paralleled the plasticizer development. The successful utilization of these special-purpose synthetic rubbers for many product applications
0
synthetic rubbers has been by the use of auxiliary materials known as plasticizers. These materials have been employed in rubber compositions for two broad, general purposes: To facilitate processing of the uncured rubber stock by softening the composition, increasing its plasticity, decreasing nerve, etc.; and to alter the properties of the final cured product by decreasing hardness, lowering brittle temperature, improving rcsistance to tear, or other effectsof similar character. These two effects of plasticizer addition are corollary. However, certain specific groups of materials have pronounced effects on one type, but only minor influence on the other group of properties. 1 Present
address, Poliook Paper Corporation, Middletown, Ohio.
