FATTY-ACYL-MODIFIED RESINS Dicyclopentadiene, Coumarone, and Indene Types ~
A. W. RALSTON, R. J. V-QNDER WAL, S. T . BALER, AND E. W. SEGEBRECHT Arniour and Company, Chicago, Ill. The general method of preparation is as follows: A quantity of crude solvent naphtha known to contain approximately 0.1 mole of resin-forming bodies is dissolved in 25 cc. of tetrachloroethane. This solution is slowly added at 25" C. t o 15 grams of anhydrous aluminum chloride suspended in a solution of 0.1 mole of the acid chloride in 75 cc. of tetrachloroethane. The time of addition is 2 hours. After this period the reaction temperature is raised to 50" C. and maintained there for 2 hours. The contents of the reaction vessel are then poured onto ice. After the hydrolysis is completed, the tetrachloroethane and unreactive portions of the crude solvent naphtha are removed by steam distillation. The hydrolyzed product is then dissolved in ether, washed with water, and dried with anhydrous sodium sulfate, and the ether is removed by distillation. When coumarone resin is used as the starting material, 0.1 mole (calculated as coumarone) is dissolved in 25 cc. of tetrachloroethane and caused to react with fatty acid chlorides in the presence of aluminum chloride, as described above. A large number of runs were made mith the above described fractions in which the molecular proportions of the acid chlorides were varied over wide limits.
HE resins formed by the polymerization of dicyclopentadiene-, coumarone-, or indene-containing fractions are useful in many branches of industry (1). The use of phenol as a modifying agent results in resins with increased solubility in alcohol and with properties differing from those 5 ) . The phenol enters into of the unmodified resins @?, chemical combination with the coumarone or indene and becomes a component of the resulting resin (4). Staudinger (6) produced modified resins by hydrogenation, and Kessler (3) produced them by means of formaldehyde. For a number of uses it is desirable that resins possess a high degree of flexibility, combined with resistance t o chemical attack and a reasonable hardness. In order to prepare from dicyclopentadiene, coumarone, or indene, resins which possess these general properties, we have introduced high-molecular weight acyl groups into the polymer. This has been accomplished by a Friedel-Crafts reaction betveen the resinforming bodies contained in the fractions and high-molecularweight fatty acid chlorides in the presence of aluminum chloride. The acylation occurs simultaneously with some degree of polymerization of the resin-forming components of the distillate under the influence of the catalysts used in the reaction. The resulting products are acylated monomers, dimers, trimers, tetramers, or higher polymers of dicyclopentadiene, coumarone, or indene. They are either very viscous liquids or solids, inany of w11ich undergo further polymerization upon exposure to air or baking a t a temperature of C, R h e n unsaturated acyl groups are added, the acylated polymers dry to hard flexible films mhen exposed to the air. When eithei. unsaturated or saturated acyl groups are present, further polymerization often takes place upon heating a t moderate temperatures to give hard plastic materials. I n some cases we have started with low-melting coumarone resins. When the latter are caused to react with fatty acid chlorides under Friedel-Crafts conditions, resins are produced with properties differing from those terizing unmodified coumarone resins, particularly as regards their flexibility in thin films.
T
Nature of the Products The Properties of the reaction Products depend someWhat upon the type of starting materials employed and upon the molecular ratio of fatty acid chlorides used for the acylation. The following is 8. general description of the properties of the acylated products obtained from the crude solvent naphthas and from the coumarone resin: COUMAROKE FRACTION. Friedel-Crafts products were prepared from this fraction by acylation with various molecular proportions of stearoyl chloride, oleoyl chloride, and linolenoyl chloride by the method previously described. (These acid chlorides are prepared from the fatty acids of linseed Oil.) In the following description "100 per cent" means that equimolecular proportions of fatty acid chlorides and coumarone were used. Where smaller proportions of the acid chloride mere employed, they are reported as percentages of that amount of acid chloride necessary for this equimolecular mixture. Stearoylation of the coumarone fraction by the use of 100, 67, 33, and 10 per cent of stearoyl chloride, respectively, resulted in a series of soft solids. A blank sample prepared by subjecting the coumarone fraction t o similar conditions also gave a soft solid. These samples were then heated a t 100' C. for 65 hours, which was selected as a convenient period. (The polymerizatioxl undoubtedly could be accomplished in a shorter time.) This process resulted in the formation of hard resins except when 67 and 100 per cent of equimolecular proportions of stearoyl chloride were used. The heat-treated stearoylated resins "ere decidedly less brittle than the heat-treated unmodified sample. The
Methods of Preparation Two types' of starting material mere used: (a) the crude solvent naphthas containing as a major constituent coumarone, indene, or dicyclopentadiene, respectively, together with lesser quantities of the other two, and (b) a commercial coumarone resin produced by the polymerization of a coumarone-containing fraction. The resin contents of the fractions' employed in this work, based upon the yield of comparatively soft resin which could be obtained, were as follows: coumarone fraction, 39 per cent; indene fraction, 74; dicyclopentadiene fraction, 60. The coumarone resin used had a melting point of 94" C. (ball and ring). 1
Obtained from the Pennsylvania Industrial Chemioal Corporation,
Clairton, Penna.
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VOL. 32, NO. 1
Determination of the free acid cantent of one of the 100 per cent acylated coumarones showed that by far the larger portion of the acid chloride had been used in the acylation. Under the mild conditions employed and in view of the molecular weights obtained, it seems unlikely that more than one acyl group is attached to each nucleus. Monomeric coumarone probably reacts as follows:
Several possible methods for the formation of acylated polymers exist. Acylated polymers may be formed either hy acylation of unacylated polymers or by polymerization of an acylated molecule with one or more acylated or unacylated molecules. Reactions of the following type probably predominate:
F1oUF.E
1. TIN%AT0
B,
AND
COATED WITH BAKED MODWED, UNMODIFIED RESIN,A ( x 3)
molecular weights of these coumarone-stearoyl chloride reaction products as determined by the cryoscopic method in benzene are shown in the following table:
0
10 33 67 100
+
306.5 317.8 361.4 557.4
416.6
The molecular weights of the acylated coumarone polymers obtained under these conditions tend to indicate that the products are essentially mixtures of dimers and trimers. Acylation with stearoyl chloride is accompanied by a decreased tendency towards polymerization of the coumarone. I n the product prepared from equimolecular proportions of coumarone and stearoyl chloride, the molecular weight determination shows that only a small amount of polymerization takes place. When these products were heated for 24 hours a t 100' C., a 8 of them underwent further polymerization. The coumarone fraction was acylated with oleoyl chloride using 10,33, and 67 per cent of an equimolecular proportion of the oleoyl chloride. The products were all soft solids which further polymerized to hard resins when haked for 65 hours a t 100" C. The molecular weight of the sample prepared from 67 per cent of the amount of oleoyl chloride necessary for an equimolecular mixture was 584.2. This molecular weight corresponds closely to that of an acylated dimer. Acylation of the coumarone fraction with linolenoyl chloride resulted in products ranging from very viscous liquids to soft solids. All of the linolenoylated coumarones formed hard resins when heated a t 100' C. for several hours. Some of these products also possessed the property of air drying, since samples exposed to atmospheric conditions formed fdms after varying periods of time. The samples prepared from 10 and from 100 per cent of the theoretical amount of linolenoyl chloride had molecular weights of 335.3 and 506.0, respectively. Upon baking a t 100" C. for 40 hours, the molecular weight of the former increased
to 564.2.
+
These in turn can again polymerize with coumarone, monomeric acylated coumarone, and polymeric mono- 07 polyacylated coumarone to produce higher polymers. The acylated products probably consist of mixtures of substances of the above nature. These are further polperized upon heating to give higher polymers. INDENE E ~ C T I O N . The products from the acylation of this fraction with 10,33,67, and looper cent of the theoretical amount of &aroyl chloride for an equimolecular reaction were highly viscous liquids or soft solids. When heated at 100" C. for several hours, the 10 and 33 per cent stearoylated products polymerized further to hard resins. The others were not affected hy this treatment. The product prepared from 67 per cent of the theoretical amount of stearoyl chloride had a molecular weight of 448.7 which indicates that it contains considerable amounts of the stearoylated dimer. Acylation of the indene fraction with oleoyl chloride resulted in all cases in the formation of highly viscous oils
JANUARY, 1940
INDUSTRIAL AND ENGINEERING CHEMISTRY
which, when heated for several hours a t 100" C., gave hard resins. The reaction products of the indene fraction and linolenoyl chloride under the conditions described were viscous oils; all of them polymerized upon heating to give hard resins. Samples were prepared from 10, 33, 67, and 100 per cent of the theoretical amount of linolenoyl chloride. The last three dried upon exposure to atmospheric conditions. The 10 per cent product had a molecular weight of 234.7, which indicated it to be a partially linolenoylated dimer. This molecular weight increased to 596.3 upon heating for 40 hours a t 100" C. The sample prepared from equimolecular proportions of indene and linolenoyl chloride (100 per cent) had a molecular weight of 1500. Upon heating, this product became insoluble in benzene so that a molecular weight could not be obtained by our method. DICYCLOPENTADIENE FRACTION. The dicyclopentadiene fraction when condensed with stearoyl chloride produced solids in the case of the 10 and 33 per cent runs. These further polymerized upon heating to give hard solids. Samples prepared from higher proportions of stearoyl chloride were liquids which showed little tendency to polymerize further upon heating. Oleoyl chloride and dicyclopentadiene yielded products ranging from solids t o viscous liquids as the percentage of oleoyl chloride was increased. All of these products changed to hard, flexible resins upon heating. The fraction was acylated with 33 and 67 per cent of the theoretical amount of linolenoyl chloride. The first product was a viscous liquid and the latter a hard resin. Both samples further polymerized in air and, when heated, formed hard resins. TABLEI. ACYLATED PXODUCTS OF COWMARONE RESIN
Aoid Chloride Stearoyl chloride
Theoretically Equivalent Quantity (Acid Chloride),
%
0
16
33 50
67
Oleoyl chloride
83 100 10 33
67
100
Linolenoyl chloride
10
23 67
100
Product Friedel-Crafts Heat-Treated Hard resin Hard resin Resin Hard resin Soft solid Hard resin Viscous liquid Hard resin Viscous liquid Semisolid Viscous liquid Semisolid Viscous liquid Viscous liquid Solid Hard resin Solid Hard resin Solid Fairly hard resin Viscous liquid Fairly hard resin Solid Hard resin Solid Hard resin Solid Hard resin Viscous liquid Hard resin '
CouhunoNE RESIN. The coumarone resin used had a melting point of 94' C. (ball and ring). It was acylated in the same manner as that used for the resin-containing fractions. The type of products obtained is shown in Table I. The molecular weight of the product formed by the use of equimolecular proportions of stearoyl chloride and the coumarone resin was 971.6.
Properties and Uses These high-molecular-weight acyl-modified resins are of particular interest because of their high flexibility. Their hardness is in many cases similar to that of the unmodified resins. Those prepared by the use of unsaturated fatty acid chlorides are of interest in the varnish industry because of their ability to form hard films upon exposure to air. These modified resins can be baked upon metallic surfaces to give thin, protective films which are flexible and adhere tenaciously to the metal. Figure 1 shows a photomicrograph of a piece of tin plate coated with an unmodified
101
coumarone resin, A , and with a resin prepared by acylation of the same fraction with oleoyl chloride, B. After baking and cooling, the plate was bent a t points a, b, and c. In the case of the unmodified resin the resin film ruptured a t the bends, whereas the modified resin film followed the bends without breaking. Because of the water resistance and flexibility of films of these modified resins, they would be useful for waterproofing leather, textiles, cellulose products, and similar materials where flexibility of the protective film is required. The solubilities of the Friedel-Crafts reaction products both before and after heat polymerization were determined in ethyl alcohol, ether, carbon tetrachloride, benzene, kerosene, turpentine, acetone, and isopropyl alcohol. The reaction products before heat polymerization are, in general, soluble in ether, carbon tetrachloride, benzene, turpentine, kerosene, and acetone, mostly insoluble in cold ethyl or isopropyl alcohols, and only slightly soluble in hot ethyl or isopropyl alcohols. After heat polymerization for 40 hours a t 100" C. the solubility varies, depending upon the specific sample, but in general is considerably less than for the unheated product. Baked samples are insoluble in hot ethyl and hot isopropyl alcohols. The stabilities of the polymerized resins in water, 18 per cent hydrochloric acid solution, and 20 per cent sodium hydroxide solution were determined. This was accomplished by sealing samples of several of the resins together with the various solutions in test tubes and examining them after definite time intervals for signs of decomposition. Observations were made after 5-day contact with the solvents at room temperature; then the tubes were heated for 24 hours a t 90" C. and again examined. The following resins were used in this test: 10 and 33 per cent linolenoylated dicyclopentadiene fraction, 10 and 67 per cent linolenoylated indene fraction, 10 and 67 per cent linolenoylated coumarone fraction, and 10 and 67 per cent stearoylated indene fraction. None of the resins showed significant change in any of the solvents a t room temperature. At the higher temperature water and the 18 per cent hydrochloric acid solution were without effect. Treatment with the hot 20 per cent sodium hydroxide solution resulted in a slight decomposition in the case of the 10 per cent acylated resins. The resins possessing a higher degree of acylation were not affected.
An attempt is now under way to improve the color of these resins. The effect of catalysts upon the polymerization and drying of those prepared from the higher unsaturated chlorides will be studied. More quantitative data as regards their comparative flexibilities will also be obtained. Literature Cited Carmody, W. H., Sheehan, TV., and Kelly, H., IND.ENQ.CHEM., 30, 245 (1938).
I. G. Farbenindustrie -4.-G., U. S. Patent 1,754,052 (April 8, 1930).
Kessler, J. J., Ibid., 1,616,321 (Feb. 1 , 1927). Rivkin, J., and Sheehan, W., IND.ENO.CHEX, 30, 1228 (1938). Rosenthal, L., U. S. Patent 1,857,333 (May 10, 1932). Staudinger, H., German Patent 504,216 (May 30, 1926).
