These masterbatches of treated resin were blended with untreated resin to prepare polyethylene containing Catanac SN in concentrations ranging from 0.25 to 5%. Four-inch disks were made by compression molding and tested for antistatic activity. Results are shown in Figure 8 (tested within a week after molding). Catanac SN antistatic agent is equally effective on low density and other types of polyethylene.
posure of the agent and plastic a t temperatures above 400’ F. should be avoided. I n the case of the polyolefins, powder or flake forms of the polymer should be used in preference to the pelletized form. Only small amounts of the agent are required to produce moldings which remain static-free for long periods of time.
Polypropylene
J. Chamberlain and Lyle Andrew, who performed many of the
Acknowledgment
T h e authors gratefully acknowledge the assistance of Ralph I n a similar fashion polypropylene flakes or powder were treated to make a masterbatch containing 10 to 5001, Catanac SN antistatic agent. When treated polypropylene was blended with untreated material and 4-inch disks were subsequently molded, again excellent static control was obtained, as shown in Figure 9 (test made a week after molding). Extruded polyethylene or polypropylene pellets cannot be readily treated with high levels of antistatic agent to make “masterbatches,” as can the powder or flake forms. Conclusions
Catanac SN antistatic agent, a cationic quaternary ammonium compound, can be successfully combined in the laboratory with many thermoplastic materials under carefully controlled processing conditions. For example, prolonged ex-
experiments; Richard Anderson and Michael Sabia, who prepared the Catanac SN in nonaqueous solvents; J. J. Robinson, G. A. Clarke, and their staffs for the analyses of samples; and Donald L. Swanson and Theresa F. Ziegler for the preparation and study of Catanac SN containing tritium. literature Cited
(1) American Cyanamid Co., Intermediates Dept., Data Sheet on Catanac SN Antistatic Agent, 1961. (2) American Cvanamid Co.. unDublished results. (3’ Carnes, J. J.: U. S. Patents 2,&626,876,2,626,877(1953). 4) Chamberlain, R. J., Zbid., 2,891,878 (1959). (5) Gruber, A. H., van Loo, LV. J., Zbid., 2,836,517 (1958). ( 6 ) Humfeld, G. P., RCA Eneineer 6, 18-20 (November 1960). (7) Lee, E. LV., Lambert, F. P.,Brit. Patent 815,662 (1959). ’
RECEIVED for review October 26, 1962 ACCEPTED January 18, 1963 Division of Organic Coatings and Plastics Chemistry, 142nd Meeting, ACS, Atlantic City, N.J., September 1962.
INHIBITORS FOR UNSATURATED POLYESTER RESINS E A R L E. P A R K E R , Pittsburgh Plate
Glass Co., Springdale, Pa.
The inhibitor system for an unsaturated polyester resin is expected to provide long storage life, fast cure, a minimum of catalyzed or uncatalyzed drift, and mechanically sound parts without any undesirable colors, odors, or side effects. A large number of compounds were screened in order to determine which would best meet these requirements. Hydroquinone, 4,4-dihydroxybiphenyI, and catechols with 3-n-alkyl, 3-isopropy1, 3-pheny1, 4-n-alky1, 4-isopropy1, 3,5-dialkyl, and 3,6-dialkyl substitutions were found to have considerable merit as inhibitors.
HE inhibitor system for an unsaturated polyester resin is Trequired to meet a number of rather difficult requirements, which vary depending on the particular application that is intended. For example, a resin to be used in matched metal molding must meet the following requirements :
taken to establish which of the known types of effective inhibiting compounds would provide the most desirable properties in a polyester resin.
I t should gel and cure as rapidly as possible without cracking, blistering, or crazing. Gelling and curing characteristics should change (drift) as little as possible as the catalyzed resin ages. T h e storage life (tank life) of the catalyzed resin should be as long as possible a t ambient temperatures. T h e storage life of the uncatalyzed resin should be as long as possible. Gelling and curing characteristics of the uncatalyzed resin should not change on long storage. T h e inhibitor should not impart color or odor to the resin, either cured or uncured.
Two polyesters were used in this work. Polyester A was prepared from 10 moles (980 grams) of maleic anhydride, 10 moles (1480 grams) of phthalic anhydride, and 22 moles (1672 grams) of propylene glycol. Polyester B contained 9 moles (882 grams) of maleic anhydride, 11 moles (1628 grams) of phthalic anhydride, and 22 moles (1672 grams) of propylene glycol. Both polyesters were prepared in a 5-liter 3-necked flask equipped with a thermometer, an inlet tube for inert gas, and a device for the azeotropic removal of water. T h e ingredients were refluxed with xylene as a solvent at 195’ C. until the acid number was reduced to approximately 50. At this point a vigorous stream of inert gas was introduced to remove the xylene and to increase the molecular weight of the polyester until a 60y0 solution by weight in ethylene glycol monoethyl ether (Cellosolve) had a viscosity of approximately I on the
Since very little has been published on this subject outside of the patent literature (7-73), a screening program was under102
l & E C P R O D U C T RESEARCH A N D D E V E L O P M E N T
Experimental
Results Obtained on Polyester Resin A Catalyzed with 1.5% Benzoyl Peroxide L.P.E., Minutes Tank Lqe, Hours Ob 24 48 100' F. 77' F. I d
Table I .
Inhibitora
IiP
Catechols Substituted in 3-Position 0.025 yo 3-methyl catechol 0 . 025y0 3-ethyl catechol 0.025 yo 3-n-propyl catechol 0 . 025y0 3-n-butyl catechol 0.05% 3-n-butyl catechol 0.08 yo 3-phenyl catechol 0 . 0 5yo pyrocatechuic acid 0 . 1 yo 3-methoxy catechol 0 . 1 % catechol (control) Nonee (control)
3.9 4.1 4.0 3.2 4.1 4.05 2.9
0,025y0 4-methyl catechol 0 . O25yO4-ethyl catechol 0 . 025y0 4-n-propyl catechol 0,0570 4-n-propyl catechol 0,025y0 4-n-butyl catechol 0,059/, 4-n-butyl catechol 0 . 025y0 4-isopropyl catechol 0.0570 4-propionyl catechol 0.0470 4-phenyl catechol 0 . 1 1% 4-chloro catechol 0.025% 4-tert-butyl catechol 0.025'% 4-n-butyryl catechol
5.3 4.5 3.5 6.5 3.4 5.0 4.3 2.75 5.8 4.5 4.6 2.9
0.017% 3,6-diallyl catechol 0.01 5% 3,5-di-sec-butyl catechol 0.02570 4,5-dichlorocatechol 0 . 0 1 yo 1,2-dihydroxynaphthalene 0 . 0 5 ~ nordihydroguaiaretic 0 acid 0 . 04y0 4-methyl esculetin
4.35 4.8 3.15 6.75 7.6 3.1
5,s J.J
2.5
3.7
3.6
...
...
4.2 4.9
3.9
...
36.9 21.2 19.3 16.3 14.2 53.4 7.9
21
6.4 5.4 6.0 4.4 5.1 3.7 1.4 6.4 9.8 0.8 6.0 5.6 7.1 6.6 5.9 5.8 8.6 2.9 4.3 4.9 8.0 2.9
19.7 20.2 24.6
8 25 22 37 8
104 91 86 ... 72 102 115 20 154 151 125 20
21.2 20.4 26.8 7.3 26.6 33.6 27.2 7.3
16 37 4 23 33 4
77 206 44 266 180 28
3.8 7.8 1.3 3.4 4.3 1.3
17.7 43.0 14.4 33.5 23.7 9.0
168
5.5 8.3 6.7
28
15 4 37 54 2
...
...
Catechols Substituted in 4-Position 3.8 3.4 32 3.8 3.1 25 3.3 2.9 24
...
4.9 3.8 5.3 ...
...
4.0 3.5 4.5 ...
144 87 77 52 58 216 23
... ...
...
... 8.4
...
Disubstituted Catechols
0.01 257, p-benzoquinone
0.025 yop-benzoquinone 0.05 yo dichlorobenzoquinone 0.025'% dichlorobenzoquinone 0 . 1 yochloranil 0 . 1yodi-tert-butyl-@-benzoquinone 0.0270 1,2-naphthaquinone 0 . 02y0 tetrahydroxyquinone O.OZyo hydroquinone 0.04y0 tetrachlorohydroquinone 0 . 025y0 ethylhydroquinone 0.025'% propylhydroquinone 0.0250/, n-butylhydroquinone 0 .05% n-propyl gallate
d
I;,
10.2 6.1 9.8 7.6 7.5 1.5 3.8 3.7 4.75 2.85 3.25 3.3
0.050/, Tenox BHA (butylated hydroxyanisole) 0.02'% lapacholf 0.02% lawsone+ 0.05% Ionol (2,6-di-tert-butyl-pcresol) 0 . o5y0 8-quinolinol 0.275 resorcinol 0 . 1yo 4-benzylresorcinol 0 . 1yo 4-tert-butylresorcinol a
6.0 10.1
4.5 2.7 3.9 2.9 3.05 2.4 2.6 2.8
Percentages of inhibitor based on uieight of polyester. =
tank life at 77' F. L.P.E. at zero hours
e
...
...
5.5 3.0 6.0 6.7 2.7
5.5 2.8 5.2 4.8
...
Quinones and Hydroquinones 5.3 5.0 33 9.4 8.9 84 9.6 8.5 68 5.2 4.8 35 8.4 8.4 37 8.1 7.9 21 7.0 6.2 92 2.8 ... 0-4 5.0 5.3 30 4.5 3.8 18 6.25 5,s 44 2.16 ... 6 3.25 3.05 14 Miscellaneous Compounds ... ... 5.0
...
3.6
3.3
2.75 3.35
3.3
...
...
...
336
...
...
106
7.9 4.8
... 28.7 ... 14.0 19.0
13
0.5
3.9
27 2 5
>508 21 73
6.0 0.7 1.3
>113 7.8 18.7
4 6 2
27 51 10 13 13
1.14 2.0 0.8 3.6 3.4
9.3 16.7 4.4 5.1 4.6 tank life at 700" F, L.P.E. at zero hours
10 10
...
Hours of storage at 77a F. of catalyzed resin before test mas run.
Styrene used contained 50 p.p.m. p-tert-butyl catechol.
f
...
32.9 26.9 21 . 7 14.4 47.0
0-4
1.5
5.2
...
...
c
Ilw
2-Hydroxy-7,Cnaphthoquinonc.
a
=
2-Hydroxy-3-(3-methyl-
2-butenyl- 7,4-naphthoquinone.
Gardner-Holdt scale. This process gives of polyester with a molecular weight in the 1000 to 1500 range. Polyester A was cooled to approximately 125' C., a t which temperature 2 parts of polyester were mixed with 1 part of styrene (inhibited with 50 p.p.m. of p-tert-butyl catechol) containing the inhibitor to be tested. If the inhibitor did not dissolve in the styrene readily, it was dissolved in the polyester a t 150' C. After the polyester was dissolved in the styrene,
the mixture was cooled to room temperature in a cold water bath. T h e L.P.E. a n d the tank life tests were run on mixtures containing polyester A with 1.5y0benzoyl peroxide as the catalyst. [The L.P.E. test was developed in the laboratories of the Pittsburgh Plate Glass Co. before the SPI gel test was accepted by the industry. T h e procedure is identical with the SPI gel test, except that a smaller test tube is used a n d only the value corresponding to the SPI total time is reported.] VOL. 2
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JUNE 1 9 6 3
103
Polyester B was mixed with styrene i n the same manner as polyester A. except that these mixtures contained 29y' styrene by weight. T h e L.P.E. and the tank life tests lvere r u n on mixtures containing polyester B with 1% of benzoyl peroxide as the catalyst. For the L.P.E. test, resin was placed in a 16 X 130 mm. borosilicate glass test tube to a depth of 3 inches. A needletype thermocouple attached to a Brown recording potentiometer was centered in this resin mass. This assembly !cas placed in a constant temperature water bath held a t 180' F. T h e L.P.E. value was taken as the time in minutes required for the resin to go from 150' F. to its peak temperature. This test was run on freshly catalyzed resin and on catalyzed resin that had been stored for 24 or 48 hcurs a t 77' F. For the tank life tests, samples of catalyzed resin Lvere placed in 2-ounce glass bottles, stored a t 77' and 100' F., and checked every 4 hours for signs of gelation. When a sample had nor started to gel a t one check time a n d was completely gelled a t the next, it was arbitrarily considered to have gelled 2 hours after the last check when it was still liquid. The value was calculated by dividing the tank life a t 100' F. by the L.P.E. value obtained on freshly catalyzed resin. T h e Iii value was similarly obtained from the tank life a t 77' F.
Table II.
Inhibitora
These terms were used as a measure of the effectiveness of inhibitors when the L.P.E. values were not comparable. Since fast cures a n d long tank lives are usually desired simultaneously, inhibitors that have large 1100 a n d values are likely to provide more desirable characteristics in the resin. I100 and I,i were fairly constant for the same inhibitor over a narrow range of inhibitor concentrations. Discussion
Tables I a n d I1 show the results that were obtained on catechols substituted in the 3 a n d 4 positions. T h e substitution of a normal alkyl group in either the 3 or the 4 position on the catechol nucleus increases the effectiveness of the compound as a n inhibitor. T h e 3-substituted compounds seem to be somewhat more effective than the corresponding 4-substituted compounds. T h e L.P.E. values drift "down" or shorter in both cases, but the degree of drift is less with the 3-compound than with the 4-compound. \%'hen the alkyl group is branched on the a-carbon atom, the L.P.E. values tend to drift '.up"
Results Obtained on Polyester Resin B Catalyzed with 1.0% Benzoyl Peroxide L. P.E., Minutes Tank Life, Hours 0 24 48 100' F. 77" F. IlW
0.015% 3-methyl catechol 0.020'7 3-methyl catechol 0.025% 3-methyl catechol 0.02% 3-ethyl catechol 0.0370 3-ethyl catechol 0 .02y03-n-propyl catechol 0 . 0 3 % 3-n-propyl catechol 0 . O4y0 3-n-propyl catechol 0.02'7, 3-isopropyl catechol 0 . o3Y0 3-isopropyl catechol 0.04% 3-isopropyl catechol 0 . 02y03-isobutyl catechol 0,047, 3-isobutyl catechol 0.03% 3-n-amyl catechol 0.047, 3-a-phenylethyl catechol 0.03yG 3-a-phenylethyl catechol 0.04% 3-a-phenylethyl catechol 0.010% 3,6-di-n-propyl catechol None (control)* 0,0157, 4-methyl catechol 0,0207, 4-methyl catechol 0.025% 4-methyl catechol 0 .OS% 4-ethyl catechol 0.02% 4-propyl catechol 0 . O3y0 4-propyl catechol 0.04'70 4-propyl catechol 0 . 0 2 % 4-isopropyl catechol 0.03Oj, 4-isopropyl catechol 0.04'% 4-isopropyl catechol 0.02?ZG 4-n-amyl catechol 0 . 03y0 4-n-amyl catechol 0.04% 4-n-amyl catechol 0.047, 4-a-phenylethyl catechol 0 . 05 yo O-( 3,4-dihydroxyphenyl)alanine
Catechols Substituted 3.45 3.1 3.8 3.7 3.9 3.85 4.95 4.6 5.75 5,15 3.25 3.15
in 3-Position 2.95 19 3.1 21 3.45 25 ... 30 5.0 59 3.0 28
7.1 4.75 5.35 5.0 5.7 5.6 6.65 6.5 3.4
6.5 4.15 4.65 4.3 4.65
7.05 4.4 5.0 4.7 5.45 5.1 6.1 6.2
...
Catechols Substituted 5.55 5.25 6.6 6.15 8.2 7.4 5.6 5.2 6.4 6 6 6 6 6.9 11 . o 10.0 5.7 6.4 7.9 6.8 9.4 8.65 5.75 6.0 7.15 7.0 8.9 8.3 6.5 '.3 3.6 3.65
...
5.5 ... ...
in 4-Position 4.6 5.3 5.9 4.6
5 6 0 9.1 5.5 6.7 8.15 5.1 5.8 6.45 6....
120 130 144 168 >336 132
84 17 29 34 40 51 54 21 3
420 113 192 170 192 >168 336
29 33 50 43 48 56 80 36 52 67 48 60 91 52 4
156 170 228 192 192 192 240 192 288 360 192 240 300 336 31
...
23
Miscellaneous Compounds >168 4.2 4.8 4.6 3' 0.04% 4,4'-dihydroxybiphenyl 28 ... 3.8 3,4 6 0.0570 phenolphthalein 45 6 3.75 ... 3.9 0.0570 diethylstilbesterol 4 8 3.65 0.05% 4,4 '-dihydroxybenzophenone 4 11 3.85 0.05% 2,4 '-dihydroxybenzophenone 4 28 3.75 ... 3.85 0.05% 2,4,6-tribromophenol 28 4 0.05y0 pentabromophenol 3,6 ... 3.6 4 28 3.75 ... 0.05% phenothioxin (phenoxathiin) 4.0 28 4 0 .OS% phenothioxin-10-oxide 3.55 ... 3.7 2 10 3.7 0.05 '7 5 7-dihydroxy-4-methylcoumarin ... ... 10 2 ... ... 3.7 0.05 phloroglucide 5 8 3.7 ... ... 0.05 Yobenzyl-P-methylumbelliferone 192 4 . 3 5.6 5.2 4.6 0.050/, 2,6-dihydroxyquinone b Styrene used contained 5 0 p . p . m . p-tert-butyl catechol. a Percentages of inhibitor based on weight of polyester.
2
104
I & E C P R O D U C T RESEARCH A N D D E V E L O P M E N T
17:
5.5 5.5 6.4 6.1 10.2 8.6 8.9 8.6 8.6 9.1 11.8 3.6 5.4 6.8 7.1 9.1 8.0 3.3 0.9
34.8 34.2 36.7 34.0 >57.5 40.5 44.5 54.0 58.8 59.0 59.3 23.8 35.9 34.0 33.7 >30.0 52.0 ... 6.8
5.2 5.0 6.1 7.7 8.0 8.1 7.3 6.3
28.2 30.2 30.8 34.3 32.0 27.8 21.8 33.7 42.4 41.7 32.0 33.6 33.6 52.0 8.5
7,: 7 . )I 8.0 8.4 10.2 8.0 1.1 8.8 1.6 1.5 1. I 1.o 1. o 1.1 1 .o 1.1 0.5 0.5 1.4 7.7
>40
7.4 11.5 2.2 2.9 7.3 7.8 7.3 7.6 2.6 2.6 2.2 54.3
or longer. This upward drift is greater with 4-substitution than kvith 3-substitution. Since a minimum amount of drift in either direction is very desirable, 3-isopropyl catechol is believed to have a very desirable combination of properties. An excellent combination of properties was also obtained with 3-n-propyl catechol. Branching on the @-carbon,as shown by the results with 3-isobutyl catechol, is less effective for prevention of downward drift than branching on the a-carbon. Compounds having oxygenated side chains are, in general. much less effective than those containing hydrocarbon side chains. This may be seen by comparing the properties of 4propionyl catechol with 4-n-propyl catechol and 4-n-butyryl catechol with 4-n-butyl catechol. Unsaturation in the side chain also appears to reduce the effectiveness of the compounds as inhibitors (note the weak activity of 3,6-diallyl catechol). T h e tables also show the results obtained with a variety of disubstituted catechols and of quinones and hydroquinones. I n general, p-benzoquinone and hydroquinone are very effective inhibitors and chemical modification of the structure tends to reduce the effectiveness of the parent compound. Hydroquinone derivatives are characterized by their rather strong upward drifts. T h e results of Table I were obtained Lvith 1.5% benzoyl peroxide, which tends to minimize the up\vard drift. LYhen similar values are obtained with lower amounts of catalyst, the upward drift is considerably greater. Quinones are more effective than the corresponding hydroquinones from which they might be obtained by oxidation. Quinones normally show a downward drift. T h e last section of Table I s h o w the results obtained with a variety of miscellaneous compounds. Derivatives of phenol are normally rather weak inhibitors, as is shown by the results with Ionol. Derivatives of resorcinol and pyrogallol are also rather ineffective inhibitors.
The last section of Table I1 shows the results obtained with a variety of miscellaneous compounds using polyester B. The most effective compound in this group was 4,4-dihydroxybiphenyl. Most of the other compounds showed very little activity and were not studied further.
Literature Cited
(1) Abrams, I. M., et al. (to Diamond Alkali Co.), U. S. Patent 3,028,361 (April 3, 1962). (2) Anderson, T. F. (to Libbv-Owens-Ford Glass Co.). Zbid., 2,559,837, 2,559,838' (July io, 1951) ; 2,607,756 (Xug. 19; 1952) ; 2,610,168 (Sept. 9, 1952); 2,632,751,2,632,753 (March 24, 1953); 2,635,089 (April 14, 1953); 2,679,493 (May 25, 1954). (3) Andrews, R. C., Peterson, N. G. (to Glidden Co.), Zbid., 2,777,829 (Jan. 15, 1957). (4) Bjorksten, J., "Polyesters and Their Applications," pp. 288-95, 418-21, Reinhold, New York, 1956. (5) Brooks. M. C.. Praper. I. A. (to United States Rubber Co.). U. S. Paient 3;028,366(April 3, i962). (6) Cass, 1". E., Burnett, R. E., Ind. Eng.Chem. 46, 1619 (1954). (7) Ellis, C. (to Ellis-Foster Co.), U. S. Patent 2,255,313 (Sept. 9,
.,
\-,
, I
~~~~~~
1041)
- '' - 1 .
(8) Fraser, G. L. (to Monsanto Chemical Co.), Ibid., 2,516,309 (July 25, 1950). (9) Gerhart, H. L. (to Pittsburgh Plate Glass Co.), Ibid.. 2,493,343 (Jan. 3. 1950). ---~, (10) Gerhart, H. L., M o d . Plastics 25, NO. 6, 86 (1947). Meyer, I:. \V., Klein, J. G. (to Glidden Co.), U. S. Patent (11) ' 2,846,411 (Xug. 5, 1958). (12) Noller, D. G., M o d . Plastics 39, No. 12, 147 (August 1962). (13) Parker. 15. E. (to Pittsburgh Plate Glass Co.). U. S. Patents ' 2,570,269'(0ct. 9,'1951) ; 2,533,787 (April 12, 1952) ; 2,627,510 (Frh. 3. 1~ 9 5 3-I )' : 2.643.985 (June 30. 1953): 2.646.416 (Julv 21. ~ 1953) ; 2,664,413 (Dec. 29; 19j3) ; '2,676,9477(Ap'ril 2?, 1954) ; 2,698,312 (Dec. 28, 1954) ; 2,740,765 (April 3, 1956) ; 2,829,120 (kpril 1, 1958); 2,844,559 (July 22, 1958). \-----
- I
\----
- 2
- > - - - I - - -
RECEIVED for review November 19, 1962 ACCEPTEDMarch 11, 1963
ENDENE AND CENTRENE POLYESTERS A NT0 N I SZ A Y NA
, Research Center, United States Rubber Go.,
Wayne, A'. J .
Unsaturated polyesters having the double bonds located toward the ends of the chain have physical properties superior to those of the isomers in which the double bonds are located toward the center of the chain. Three pairs of such isomers were synthesized, cured, and tested. HE importance of placing double bonds in polymeric Tn~aterials at the ends of the chain has been recognized theoretically for some time ( 3 ) , but no experimental proof has been given. T h e present work shows that in the case of polyesters the materials with double bonds located toward the ends of the chain (Endenes) exhibit, upon curing, physical properties substantially improved over those of the isomers having the double bonds in the center (Centrenes). Three pairs of isomeric polyesters have been prepared and tested; in all cases the Endene structures had superior physical properties. I n one set (Table I) the Endene A isomer was prepared by first esterifying 2 moles of succinic anhydride with 3 moles of diethylene glycol and then adding to the saturated spine unsaturated terminals in the form of 2 moles of maleic anhydride. T h e corresponding Centrene B isomer was prepared by first
reacting maleic anhydride with diethylene glycol and then adding the succinic anhydride to that unsaturated spine, forming saturated terminals. I n the above syntheses there is little likelihood of skeletal isomerization (change of relative position of building blocks in the chain), since in the formation of the spine only one kind of acid and glycol is used and the terminal acid anhydride is added to the spine under very mild conditions (120' to 130' C . for 30 minutes) without water formation. No catalysts are used in the procedure. I n the case of both Endene A and Centrene B, use of identical components and proportions as well as identical esterification procedures will result in essentially identical molecular weight distributions ( Z ) , thus eliminating this latter factor from affecting the differentiation of properties of the two isomeric forms. Therefore, we ascribe the differences in physVOL. 2
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JUNE 1 9 6 3
105
