Epoxy Fatty Acid Ester Plasticizers FRANK P. GREENSPAN AND RALPH J. GALL Buflalo Electro-Chemical Co., Inc., Division of Food Machinery & Chemical Corp., Buffalo7 , N . Y .
A
CHa(CH2)7CH-CH-(CH2)?-C00i\Ie
LL vinyl plasticizers in common impart relatively permanent flexibility, toughness, and flow properties to the otherwise brittle and nonelastic polyvinyl resins. They differ in degree of compatibility, permanence, efficiency, and a host of special properties-e.g., low temperature flexibility, flame resistance, and electrical properties. No single plasticizer structure satisfies the varied combination of properties required for each of the multitude of diversified end uses of polyvinyl resins. The chemical literature (16) records several thousand different compounds variously recommended as vinyl plasticizers, although no more than a few hundred have had commercial importance. Five to six different classes of plasticizers constituted the bulk of the approximately 150,000,000 pounds of vinyl plasticizer produced in the United States in 1951 (9). In this paper is described a new series of vinyl plasticizers, epoxy fatty acid esters, distinguished by generally good over-all plasticizer properties combined with unique attributes of their own. These have been studied in our laboratories over the past several years as part of a broad program of research on epoxidation and hydroxylation reactions and their applications.
‘O/ CHa(CH$)4-CH-CH-CHL-CH-CH-( ‘O/
Methyl epoxystearate
CH2)T-COOMe
-
‘O/ Methyl 9,10,12,13-diepoxystearate
While the reactions of a per acid with unsaturated compounds have been known for a long time (1-3, 11), to Swern and Colleagues a t the Eastern Regional Laboratories belongs the credit for the development of practical, streamlined, and efficient procedures for conducting these reactions in nonsolvent media. Rwern e t al. ( 7 , 2 6 , 27) subjected a large number of olefinic hydrocarbons and unsaturated fatty chemicals, including esters and the naturally occurring triglycerides, to epoxidation and hydroxylation with peracetic and performic acids, isolating in good yield the corresponding epoxy and dihydroxy compounds. Numerous variations have been proposed for improving these reactions (8, 10, 20). The development of highly concentrated hydrogen peroxide (14) and the commercial introduction of peracetic acid ( 5 ) have given additional stimulus to the commercial utilization of these reactions until today epoxidation-hydroxylation reactions with per acids have acquired unit process importance industrially. Hydroxylation reactions are most conveniently carried out by an in situ procedure wherein hydrogen peroxide-e.g., 50% hydrogen peroxide-is added to an acetic or formic acid solution of the unsaturated material in the presence of approximately 1% of mineral acid ( 2 6 ) . Epoxidation reactions are conducted more generally utilizing a prepared per acid. In situ procedures also have been developed for this reaction in recent years (10).
STRUCTURE AND PREPARATION
Epoxy fatty acid ester plasticizers are the products of epoxidation of unsaturated fatty acid esters of monohydric and polyhydric alcohols with a per acid. Epoxidation together with its companion reaction, hydroxylation, can be schematically represented as follows:
I 1 -c=cI
PLASTICIZER PROPERTIES I
1 1 I t OH OH
,
-C-c-
-C-C-
I
/
OH 0
c=o R
Hydroxy-acyloxy derivative Utilizing an aliphatic per acid-e.g., peracetic, or hydrogen peroxide-together with an aliphatic acid, a fatty acid or derivative can be readily converted into the corresponding epoxy or dihydroxy compound dependent upon experimental conditions (4). Epoxidation and hydroxylation are one and the same reaction, the latter being the end result of subsequent ring opening of the initially formed epoxy compound, as illustrated. LOW temperature, short reaction time, and low concentration of hydrogen ion favor the epoxidation reaction. Epoxidation reactions are accompanied generally by some ring opening, so t h a t the reaction products consist of small amounts of hydroxy-acyloxy compound along with the desired epoxy derivative. The epoxy compounds to be expected from epoxidation of a mono-unsaturated and di-unsaturated fatty acid ester are illustrated
Since esters as a class are of general interest as plasticizers, it is not surprising to find in the literature several references (10, 18, 10)pointing to the potential value of epoxy fatty acid esters as vinyl plasticizers. Such references have generally been in the form of preambles to new epoxidation procedures developed eince 1945. Terry and Wheeler ( U ) have recently described polyvinyl resin compositions containing epoxy fatty acid esters. Plasticizers are generally polar compounds, which on incorporation into a vinyl resin modify the strong secondary forces linking the polymer chains, thereby imparting to the polymer a greater freedom of motion resulting in elasticity and flexibility. Chemically, plasticizers may be classified as relatively nonvolatile solvents. Compatibility and permanence are key considerations in the selection of a plasticizer. Compatibility may be considered a measure of solvency action. The effect of the introduction of an epoxy group on compatibility of a typical unsaturated ester, butyl oleate, is illustrated in Table I. For comparative purposes, the saturated ester, butyl stearate, has been included. Introduction of an epoxy group greatly increases the compatibility of the re-
COMPATIBILITY OF FATTY ACIDESTERS TABLE I. COMPARATIVE WITH VINYLRE SINS^
2722
Butyl oleate Butyl epoxystearate Butyl stearate a
Ratio of resin t o plasticizer 2 to 1.
Poor compatibiiity Compatible Poor compatibility
December 1953
5
f
INDUSTRIAL AND ENGINEERING CHEMISTRY
2723
sultant ester with polyvinyl chloride. The structure containing the polar epoxy group may be considered an internal ether and therefore responsible for the increased polyvinyl chloride solvency of the epoxy esters. T o compare the plasticizer properties of epoxy fatty acid esters R'COOR with changes in R, a series of monohydric and polyhydric alcohol esters of oleic acid was epoxidized. Additionally, the influence of multiple epoxy groups in the chain R' was studied by epoxidation of the corresponding esters of polyunsaturated fatty acids. The specific polyunsaturated acids employed were soybean fatty acids and cottonseed fatty acids. The esters were epoxidized with peracetic acid by a modified procedure designed to give a low iodine number. The specific procedure used for epoxidation changes somewhat the physical properties and performance of the resultant plasticizers. Analyses of the resultant epoxy structures are given in Table 11. Physical properties of the epoxy esters studied are detailed in Table 111. Specific gravities varied from 0.902 for butyl epoxyester of cottonseed fatty acid to 0.999 for epoxy soybean oil. The low specific gravities exhibited in general by the members of the series is of economic importance, since many plastic materials are sold on a yardage basis.
possess a wide boiling range. For the series, the boiling points ranged from 171' to 261' C. a t 4 mm. for low molecular weight members, methyl epoxyester of soybean fatty acid, to nondistillable, for high molecular weight members, epoxy soybean oil. The boiling points of the epoxy esters were uniformly higher than that of the precursor unsaturated ester. Thus, butyl oleate distills at 173' to 225" C. a t 75 mm. while the corresponding epoxy ester showed a 179" to 269' C. range a t 4 mm. The low viscosity exhibited by most of the esters is worthy of note. Epoxy fatty ester plasticizers showed good compatibility with nitrocellulose, ethylcellulose, polystyrene, and methyl methacrylate, in addition to polyvinyl chloride (Table IV).
DATAFOR EPOXYFATTY ACIDESTERS TABLE 11. ANALYTICAL
Plasticizer performance data were obtained on milled sheets prepared on a laboratory roll mill. The formulations employed were as follows: Parts by Weight 65 70 35 30 1 1
Epoxystearates Methyl Butyl Ethylene glycol monobutyl ether Epoxy esters of cottonseed fatty acids Methyl Butyl
Oxirane Oxygen, % .~
Iodine No.
4.17 4.03 3.36
2.2 2.7 2.1
3.75 2.13
Epoxy esters of soybean fatty acids Methyl Butyl n-Octyl Tetrahydrofurfuryl Diethylene glycol monobutyl ether Triglyceride (soybean oil)
.
5 16 4 01 3.73 4 20 3.61 6.04
2.0 2.9 3 1 3.9 9.7 2.2 2.4 3.4
The individual esters as prepared are multicomponent mixtures consisting of the dominant epoxy ester, the corresponding hydroxy acyloxy cgmpounds, and unreacted unsaturates, and
TABLE IV. COMPATIBILITY OF METHYL EPOXYESTER OF COTTONSEED FATTY ACIDSWITH VARIOUSPOLYMERS Resin Polyvinyl chloride Nitrocellulose Cellulose acetate Ethylcellulose Polystyrene Methyl methacrylate
Ratio of Resin t o Plasticizer 2:l 2:l 3:l 3:l 3:l 4:l
Compatibility Very good Good Poor Very good Good Good
The hand, drape, and clarity of the resultant films varied from good to excellent. The data are detailed in Table V. The epoxy esters uniformly showed excellent plasticizing action; efficiency generally was equal to or better than dioctyl phthalate. The plasticizing efficiency of individual members of the series varied with the molecular weight of the ester. Good low temperature flexibility is exhibited by epoxy ester plasticizers. The permanence of the plasticizers under various conditions is illustrated in Table VI. Degree of permanence varied from fair to excellent, dependent upon structures and molecular weight.
TABLE 111. PHYSICAL PROPERTIES OF EPOXY FATTY ACIDESTERS"
Specific gravity a t 2qa
c.
ZOO/
Boilingnoint at4mm., OC. Color (Pt-Co), No. Odor Acid number Cloud point or freezing point
Dioctyl Phthalate 0.986
Methyl Epoxystearate 0.929
Butyl Epoxystearate 0.911
Methyl Epoxy Ester of Cottonseed Fatty Acids 0.919
222-230 50-100 Moderate
177-248 250 Mild, fatty type 9.4 Turbid at. -4O C.; crystallized a t - 5 . 6 ' C. 1.4518
179-269 150 Mild, fatty type Nil Crystallized a t -120 c.
80 Mild, fatty type 1 .6 Crystallized at + 7 . 0 ° C.
1.4510
17
18
0.1
Stiff gel, -55O
C.
Refractive index a t 1.4851 25' C . Viscosity a t 20' C., 01)s. 80
Specific gravity a t 200
c.
ZOO/
Boiling point a t 4 mm. Color (Pt-Co), No. Odor Acid number Cloud point or freezing point
Butyl Epoxy Ester of Soybean F a t t y Acids 0.918 19:-261' 80.
C.
Mild, f a t t y type 1.5 Turbid a t +5O C.; crystallized a t - 8 . 5 ' C. 1.4520
n-Octyl Epoxy Ester of Soybean Fatty Acids 0.917
..... 80 Mild, sl. fatty type 2.8 Turbid a t + 5 . 5 " C * crystallized a t " t 3 . 0 ' C. 1 ,4560
Butyl Epoxy Ester of Cottonseed F a t t y Acids 0.902
Methyl Epoxy Ester of Soybean Fatty Acids 0.948
1 ,4489
191-268 75 Mild, f a t t y type 1.8 Turbid at + l o C.; crystallized a t -20 c. 1 ,4483
171-261 55 Mild, fatty type Nil Turbid at. +4O C.; crystallized at + 3 . 5 0 c. 1.4535
12.4
14.8
20
.....
Tetrahydrofurfuryl Ethylene Glycol Epoxy Ester of Monobutyl Ether Soybean F a t t y Acids Epoxystearate 0.999 0.924 50% distillable: 225-296' C. decomposes 25. Mild, f a t t y type 4.4 Turbid a t - 4 . 0 ° C.; crystallized at -6.5'C. 1 ,4662
.....
Diethylene Glycol Monobutyl Ether Epoxy Ester of EPOXY Soybean Fatty Acids Soybean Oil 0.972 0.998
I.B.P.205' C.
Will not distill
275 300 Slight fatty type Mild, fatty type Nil 3.0 Turbid a t 0 . 0 " C.; Turbid a t -8.0° crystallized a t C.; cryst,allized + 0 . 5 " C. a t -15' C. 1.4510 1 ,4568
Will not distill 175 Mild, fatty type 1.2 Turbid a t - 6 . 0 ° C.; crystallized a t - 7 . 5 ' C. 1.4713
Refractive index a t 25O C. Viscosity a t 20" C., cps. 19 34 75 23 49.1 537 a All epoxy esters tested a t 25' C. aye ingoluble in water. and soluble in gasoline, mineral oil, methanol, ethyl alcohol, benzene, chloroform, acetone, and ethyl ether, except for epoxy soybean 011which IS insoluble in methanol.
Vol. 45, No. 12
INDUSTRIAL AND ENGINEERING CHEMISTRY
2124
MINUTES 15
5
0
oxidative attack leading to color contributing carbonyl groups. The initial degradation appears to be a random splitting out of hydrochloric acid from the polymer; the released hydrochloric acid in turn catalyzing the progressive further polymer breakdown. Stabilization systems for chlorinated polymers are dependent upon addition of a stabilizer believed to function by removing released hydrochloric acid, reacting with the double bonds of the formed polyene inhibiting oxidation of the polyene or inhibiting free radical transfer. The epoxy group of the plasticizers under discussion are excellent hydrochloric acid scavengers; hydrochloric acid absorption occurs readily:
45
30
I
-C-C-
1
\/ 0
Figure 1.
+ HCl ---+
I I
-C-C-
/ !
OH C1
The result is a retarded polymer degradation and diminished color formation. Where processing conditions are mild, epoxy fatty acid ester plasticizers may be used without added stabilizer. With the addition of metallic stabilizers, greatly enhanced stabilizing action can be achieved, frequently rvith use of less than conventional stabilizer amounte. Various metallic stabilizers, notably those based upon cadmium and barium, are believed to behave synergistically, with epoxy compounds as far as stabilizer properties are concerned.
Heat Stability 165" C.
1. Dioctyl phthalate 2. Butylepoxy stearate 3. Methyl epoxy ester of cottonseed fatty acids 4. Butyl epoxy ester of cottonseed fatty acids 5. Butyl epoxy ester of soybean fatty acids 6. Epoxy soybean oil-1
HOURS
io0
0
STABILIZING ACTION
200
300
400
500
Epoxy fatty acid ester plasticizers show inherently good stabilizing action against heat and light even in the absence of added stabilizers. The inherent stabilizing action is indicated in the accompanying figures illustrating the performance of typical epoxy esters compared to dioctyl phthalate in milled sheet formulations. The sheets were formed by milling a t 132" t o 142' C. for 10 minutes utilizing the following formula:
67 % 33%
Geon 101 Plasticizer
Figure 1 shows the performance of these milled sheets when exposed to 165' C. over a period of 45 minutes. The greater stability of the epoxy ester formulations is immediately apparent. Milled sheets containing epoxy fatty acid ester plasticizer similarly show excellent light stability (Figure 2). Light stability determinations were made utilizing a slightly modified ASTM procedure. Epoxy esters used as coplasticizers-i.e., as a partial replacement for a conventional plasticizer, dioctyl phthalate-conferred good heat and light performance properties on the formulated sheet. The unique stabilizing action of the epoxy fatty acid esters is to be attributed to the presence of the epoxy group in the plasticizer chain. Modern theory holds t h a t the degradation of a polyvinyl chloride polymer under heat or light excitation is a complex series of reactions proceeding initially through a dehydrochlorination and leading to a polyene structure:
H H H H H H H H
-d-J-d-J-d-d-d-dbl E !T
A1
bl
Ll
A
H H H H H H H H
-b=A-A=c-C=C-C= ! '
Light Stability
Butyl epoxy stearate Butyl epoxv ester of soybean fatty acids Methyl epoxy ester of soybean fatty acids a. Butyl epoxy ester of cottonseed fatty acids 6. Methyl ~ D O X Sester of cottonseed fatty acids 7. Epoxy soGbean oil 2. 3.
4.
Epoxy fatty acid esters appear to be of broad general utility applicable to a wide range of vinyl processing techniques and products that feature the industry today.
+
4 A
Figure 2.
1. -. n i n r t v l nhthalatr ....._._._
I
!
&
EXPERIMENTAL
-+
HC1
Color formation accompanies the progressive appearance of chromophoric carbon-carbon double bonds. In turn, the double' bonds of the degraded polymer are potentially the site of further
MATERIALS.Spencer Kellogg & Song, Inc., supplied the alkali refined superior grade sovbean oil (iodine number 135) that wa6 used. Methyl oleate (roodine number 90) was obtained from Emery Industries, Inc. Butyl oleate (iodine number 74) and ethylene glycol monobutyl ether oleate were prepared by esterification of the respective alcohols with a distilled oleic acid (Emery 210) in the presence of
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
December 1953
2725
TABLE V. COMPARATIVE EVALUATION OF POLYVINYL CHLORIDEMILLEDSHEETSPLASTICIZED WITH EPOXY FATTY ACIDESTERSO
Modulus at 100% elongation at 25O C., lb. per sq. inch Ultimatetensilestrength at 25O C . , lb. per sq. inch
Butyl Epoxy Ester of Cottop seed 1590
Methyl Epoxy Ester of Soybean 810
Butyl Epoxy Ester of Soybean 1030
n-Ootyl Epoxy Ester of Soybean 1210
Ethylene Glycol Monobutyl Ether Epoxystearate 1020
Diethylene Glycol Monobutyl Ether Epoxy Epoxy SoyEster of bean Soybean Oil 1130 1780
2780
2640
2430
3220
2970
2450
2560
2380
2760
2450
2710
2840
Elongation at 25' C., %
370
410
430
350
370
450
420
340
400
420
390
340
Shore Durometer hardness, at 25' C.
76
70
69
79
80
65
70
76
68
70
72
80
Efficiency % " As per hardness As per modulus
35 35
32 32
32 32
32 33
33 33
30 30
32 32
35 34
32 32
32 32
33 33
38 38
-40
-42
- 44
- 46
- 32
- 55
Clash and Berg low ternperature flexibility, c
Methyl Epoxy Dioctyl Methyl Butyl Ester of Phthal- EPOXY-EPOXY- Cottofstearate stearate ate seed 1280 1030 850 1670
Tetrahydrofurfuryl Epoxy Ester of Soybean 960
-30
-43
-56
-27
-40
-16
c.
65% resin! 35% plasticizer, 1% cadmium-barium stabilizer, except where noted. 30% plasticizer. Shore Durometer hardness at 75 i: 2. Modulus 100% elongation at 1300 f 100 pounds per square inch.
1% sulfuric acid, water washed, alkali refined, and vacuum distilled. The ethylene glycol monobutyl ether oleate was not distilled. T h e ethylene glycol monobutyl ether used was a commercial product supplied by Carbide & Carbon Chemicals Co. Methyl ester of cotton seed fatty acids (iodine number 80) and butyl ester of cotton seed fatty acids (iodine number 67) were similarly prepared from the respective alcohols and distilled cottonseed fatty acids from W. C. Hardesty Co., Inc., iodine number 90. These esters were distilled. Methyl ester of soybean fatty acids (iodine number 120), and butyl ester of soybean fatty acid (iodine number 109) were prepared by esterification of soybean fatty acids from W. C. Hardest Co., Inc., iodine number 130, with the respective alcohols. 3 0 t h esters were distilled. T h e peracetic acid used was the 40% commercial product of the Buffalo Electro-Chemical Co., Inc.
15
."
ANALYTICAL.Oxirane oxygen was determined by the modified method of Swern et al. (19). The Hanus method (12) was employed for iodine number determinations. Acid number (IS) was determined by the standard procedure. PREPARATION OF EPOXY FATTY ACIDESTERS.The epoxidation procedure used was similar for all of the esters prepared. Reaction times generally varied between 4 and 6 hours; 104% of the calculated amount of peracetic acid required for reaction with the double bonds present was used. The procedure is illustrated for the preparation of methyl epoxystearate. One hundred grams of methyl oleate (iodine number 90) and 3.5 grams of anhydrous sodium acetate were weighed into a threenecked flask equipped with a reflux condenser, thermometer, and a mechanical stirrer. Seventy grams of a 40% peracetic acid solution (104% of the calculated amount) were added slowly over a period of 1 hour; the temperature was held between 20" and 25" C. The reaction mixture was maintained a t this temperature for approximately 3 hours or until periodic titrations indicated t h a t 80 t o 85% of the peracetic acid had been consumed; then i t was warmed a t 50' to 60" C. for 1 additional hour to complete the reaction. The reaction mixture was poured into a separatory funnel and the aqueous layer removed. The oil layer was washed free of acetic acid with successive portions of warm water (45" to 50" C.), dried with anhydrous sodium sulfate, filtered, and analyzed. The resultant product showed the following analysis Oxirane oxygen, % Iodine number
4.2 2.2
PHYSICAL PROPERTIES OF EPOXYPLASTICIZERS. Specific gravity was determined at 20' C./2Oo C. with a Westphal balance.
Boiling points were measured at 4 mm. using a modified ASTM procedure ( D 86-52). Color was determined as per ASTM Method D 268-49/4b. Cloud point and freezing point determinations were made employing ASTM method D 97-47. Refractive index measurements were made a t 25' C. with an Abbe refractometer. Viscosity determinations were made a t 20" C. employing a n Ostwald viscometer. Solubility determinations were made at 25" C. for a 50-50 mixture (by volume) of epoxy ester and solvent. PERFORMANCE EVALUATION OF EPOXY PLASTICIZERS. Plasticizer and vinyl resin (Geon 101) were milled on a roll mill and observations made of speed and ease of fluxing. Milled sheets, so prepared, were then examined for bleed, clarity, tear resistance, and flexibility. Performance of esters rated as poor (Table I ) were characterized by one or all of the following: partial or slow fluxing on the roll mill, opaqueness, and low tear resistance of formed sheets. Compatibility ratings were assigned to those esters showing good fluxing (30 to 60 seconds) as well as good tear resistance, and absence of bleeding of milled sheets. Observations were made within a few hours of milling. Compatibility ratings of epoxy fatty acid ester plasticizers with various polymers (Table IV) were based upon the characteristics of films cast from solvents in the ratio of resin to plasticizer noted. Cast films were (1) air-dried a t room temperature and ( 2 ) oven-dried overnight a t 70" C. in an air circulating oven. Examination was then made of the cast films for such features as clarity, gloss, surface smoothness, hardness, flexibility, strength, brittleness, adhesion, and bleeding, and ratings were assigned, PHYSICAL TESTSON MILLED SHEETS. Modulus a t 1 0 0 ~ o elongation, ultimate tensile strength, and ultimate per cent elongation were determined with a modified Dillon tensile tester using the standard ASTM method for rubber and related materials. Dumbbell specimens were die cut from molded 75-mil sheets and prior to testing were conditioned for 24 hours a t 25" C. and 50% relative humidity. Shore hardness was determined as the Durometer reading after 10 seconds contact with a 75-mil molded sheet. Efficiency per cent plasticizer, the per cent of plasticizer required to give a Durometer hardness of 75 & 2 and a modulus a t 100% elongation of 1300 f 100 pounds per square inch, was interpolated from hardness and modulus a t 100% elongation for milled sheets containing 25,30,35, and 40% plasticizer. Low temperature flexibility was determined according to the Clash and Berg method (6). These results are shown in Table V.
INDUSTRIAL AND ENGINEERING CHEMISTRY
2726
TABLE VI.
PERMANENCY OF PLASTICIZED
Loss after 10 Days, % I n air, I n water, In oil, 60' C . 25' C. 25' C. 0.6 0.2 11.6
Dioctyl phthalate Epoxystearates Methyl
1.7
22.3
None
2.4
0.6
22.2
Ethylene glycol monobutyl ether
0.9
0.2
24.3
Very slight afler 2 weeks Sone
*
*
Epoxy esters of soybean fatty acids Methyl
5.6
2.1
13.3
None
5.9
1.1
18.4
None
6 4
3.1
21.5
None after 2 weeks
7.2
I .2
23.7
Sone
71-Octyl
1.oc
0.9
24.5
Sone
Tetrahydrofurfuryl
0.5
3.5
16.5
Diethylene glycol monobutyl ether
0.6c
1.6
20.7
None after 2 weeks None
Triglyceride (soybean oil)
0
0.5
9.4
' 30% plasticizer. Bleeding.
PERNASENCYEVALUATIOX. Plasticizer permanency was determined by measurement of losses in air, water, and oil (Table VI). Migration tests were conducted with lacquered and varnished surfaces. i\Iilled sheets, 3 X 6 X 0.004 inch, were employed for all tests. Details of procedure follow: Samples of plasticized sheet were placed in an air circulating oven a t 60" C. for 10 days, and the weight loss over this period was determined. Plasticizer extracted by water was determined by immersion of weighed milled sheet samples in distilled water a t 25 C. over 10 days. The water was changed five times a t regular intervals over the test periods. The sheets were then dried a t 70" C. for 2 hours, reweighed, and the per cent loss in weight calculated. Plasticizer extracted by oil Tvas determined by immersion of the weighed milled sheet samples in 100 ml. of white mediumheavy mineral oil a t 25" C. over 10 days. The oil was changed three times during the test period. The samples were washed with hexane followed by petroleum ether, dried, reweighed, and the per cent loss in weight calculated. Migration tests were run by fastening milled test sheet strips with thumb tacks to a white nitrocellulose lacquered surface, and to a varnished surface. The effects of the plastic specimens on the respective finishes mere recorded after 1, 2, 4, and 12 weelis. The color changes of formulated vinyl films were observed during the milling cycle of 5 minutes a t l 5 5 O C. as well as during pressing, 12 minutes a t 144' C. (Table VII).
STABILITY O F P L A S T I C I Z E D FILIIS T O
HEAT
AND
ULTRAVIOLET LIGHT Heat Stability Milled Pressed Poor Poor
Ultraviolet Light Stability Very good
Good Very good
Fair Good
Excellent Very good
Yery good
Good
Excellent
Good Very good
Good Good
Very good Very good
Very Very Very Very
good good good good
Good Good Good Good
Very good Very good Very good
Very good oil) Very good
Good Good
Excellent Excellent
...
Severe aftcr 2 weeks Yery slight after 2 weeks considerable after 2 weeks Slight after 2 weeks Slight after 2 weeks
Butyl
6 5 % resin, 35% plasticizer, 1% cadmium-barium stabilizer.
Dioctyl phthalate Epoxystearates Methyl Butyl Ethylene glycol monobutyl ether Ewoxv ester of cotton-
Migration Test Varnish Lacquer Very slight Very slight
10.7
Butyl
TABLEVII.
SHEET"
Butyl
Epoxy esters of cottonseed fatty acids Methyl
Vol. 45, No. 12
None after 2 weeks
Considerable after 2 weeks Slight after 2 weeks Considerable after 2 wee ka &-one after 2 weeks Considerable after 2 weeks None after 2 weeks
Heat stability tests were conduct>ed at, 165" C. in an air circulating oven using 1 x 1 X 0.075 inch pressed samples. The samples were prepared using a 10-minute milling cycle followed by 2-minute pressing. Color changes were compared for 5, 15, 30, and 45 minutes of exposure (Figure 1). Ultraviolet light st,ahility tests (Figure 2) were conducted using a slight modificat,ion of ASTM test met,hod D 620-40. Samples were exposed for 100, 200, 300, 400, and 500 hours and examined for color change, embrittlement, and bleeding. The ult'raviolet light stability characteristics are reported in Table S'II. LITERATURE CITED
(1) Arbuaow, B. d..a n d Michailow, B. M., J . prakt. C'hem., 127, I (1930). (2) Boeseken, J., a n d Schneider, G. C. C . C., I b i d . , 131, 286 (1931). (3) Boeseken, J., S m i t , W. C., a n d G a s t e r , A , , Proc. Acad. Sei. Amsterdam, 32, 377 (1929). (4) Buffalo Electro-Chemical Co., Bull. 16, "Epoxidation a n d H y droxylation Reactions with Hydrogen Peroxide a n d Peracetic -4cid." (5) B u f f a l o Electro-Chemical Co., Bull. 4 , "Peracetic Acid 407i." (6) Clash, R. F., J r . , a n d Berg, R . lI,, IND. ENG.C H E x , 34, 1218-22 (1942). (7) Findlay, T . W., Swern, D., a n d Scanlan, J. T., J . Am. Chem. SOC.. 6 7 . 4 1 2 (1946). (8) G r e e n s p a n , F. P., IND. ENG.CHEX.,39, 847 (1947). (9) Modern Plastics,29, 106-107 (October 1951). (10) Niederhauser, W.D., a n d Koroly, J. E., L-,S.P a t e n t 2,485,160 (1949). (11) Prileschsjew, N., Ber., 42, 4811 (1909). (12) Scott, W. W., "Scott's S t a n d a i d M e t h o d s of Chemical h a l y s i s , " N. H . Fuiman, E d i t o r , p 1 7 6 i , New Yolk, D Van N o s t i a n d Co.. 1939. (13) I b i d . , p. 1844. (14) Shanley, E. S., a n d Greenspan, F. P., IND. EXG.CHEW,39, 1536 (1947). (15) Simonds, H. R., a n d Ellis, C., "Handbook of Plastics," p. 251, New York, D. V a n N o s t r a n d Co., 1943 (16) Swern, D., Billen, G. N., Findley, T. W., arid Scanlan, J. T., J . Am. Chem. SOC., 6 7 , 1 7 8 6 (1945). (17) . . Swern, D., Billen, G. N., a n d Scanlan, J. T , , Ihzd., 68, 1904 (1946j , (18) Swern, D., a n d Findley, T. W., U. S.P a t e n t 2,569,502 (1951). (19) Swern, D., Findley, T. W., Billen, G. N., a n d Scanlan, J. T., Anal. Chem., 19, 414 (1947). (20) T e r r y , D. E., a n d Wheeler, D. H . , U. S. P a t e n t 2,458,484 (1949). (21) Ibid., 2,559,177 (1951). RECEIVED for review December 16, 1952. ACCIGPTED September 23, 1953. Presented before the Division of Paint, Varnish, a n d Plastics Chemistry a t the 122nd Meeting of the A?~ERIcAN CHEMICAL SOCIETY,Atlantic City, s.J.
