US3149088A - Vinyl chloride polymers plasticized with fumarate adducts - Google Patents

Description

United States Patent "ice 3,149,088 VINYL CMORIDEI POLYMERS PLASTICIZED WITH FUMARATE ADDUCTS Joachim Dazzi, Basel, Switzerland, assignor to Monsanto Company, St. Louis, Mo, a corporation of Delaware No Drawing. Original applications Feb. 8, 1954, Ser. No. 408,985, and Oct. 14, 1955, Ser. No. 540,645, now Patent No. 2,938,044, dated May 24, 160. Divided and this application Nov. 4, 1959, Ser. No. 850,764

4 (Ilaims. (1. 26031.8)

The present invention relates to derivatives of linoleic acid and technical mixtures of unsaturated fatty acids which contain linoleic acid, and more particularly provides new and valuable adducts of linoleic acid and such mixtures thereof, the method of producing the same, and Vinyl chloride polymers plasticize with the new adducts.

According to the invention there are provided polycarboxylate-containing adducts in which from 2 to 4 moles of the alkyl fumarate having from 1 to 8 carbon atoms in the alkyl radical are combined at the acid portion of an ester selected from the class consisting of alkyl linoleates and the alkyl esters of a tall oil unsaturated fatty acid fraction comprising linoleic acid wherein the alkyl radical has from 1 to 8 carbon atoms.

The present esters are prepared by heating appropriate esters of linoleic acid or of said tall oil fatty acid fraction with appropriate esters of fumaric acid. Depending upon the reaction conditions and the nature of the individual reactants, there occurs addition of from 2 to 4 moles of the dicarboxylic component to the linoleate. During the heating, the olefinic double bonds of the linoleate probably shift to a conjugated position with formation of an isolinoleic acid structure, and one mole of the fumarate adds to the conjugated compound by a Diels-Alder reaction to give a cyclic structure, thus:

isomerization -C 2.CH: CH.CH: OH-

funiarate OH2.OH.CH:CH.CH

(DH-(I311 YO 0( 0 O OY From one to 3 additional moles of fumarate combine with the acid chain of the linoleate at one or more carbon atoms, with probable shifting of the olefinic double bond and introduction of 1,2-bis-(carboalkoxy)ethyl CHO 0 0 Y 0H,c o OY radicals into the molecule. Thus one mole of methyl linoleate with two moles of ethyl fumarate gives an adduct which has the possible formula cage 0 0 onion;

CH0 0 O CHzCHa CH3(CH2)lCH2CZCH.CH.CHCH (CH2)GCO 0on5 CHCH (lHscHzoo dooomorr The olefinic group of the Dials-Alder adduct remains unsaturated even when as many as 3 moles of the fumarate are combined with said aduct. A 1:3 linoleatefumarate adduct probably has a structure like that of the 1:2 methyl linoleate-ethy1 fumarate adducts shown above, except that one more l,2-bis(carboalkoxy)ethyl group is substituted on the chain and the olefinic double bond has shifted to another position. Generally, irrespective of reactant quantities and reaction conditions, the reaction proceeds with formation of adducts of various linoleatefumarate ratios. However, the addition reaction may be directed to the formation of mixtures of compounds hav- 3,l49,3 Patented Sept. 15, 1964 ing a predominantly greater proportion of fumarate in the adduct.

As disclosed in the Butler U.S. Patent No. 2,637,421 esters of the higher mono-olefinic fatty acids form adducts with the alkyl fumarates to give adducts in which from 2 to 4 moles of the fumarate have combined at the long chain fatty acid portion of said higher ester. When employing, instead of the alkyl linoleates, the alkyl esters of a tall oil unsaturated fatty acid containing linoleic acid, the addition product contains not only the linoleatefumarate adducts but also adducts of the fumarates and esters of the other unsaturated constituent of said tall oil acid fraction, i.e., oleic acid. As will be hereinafter disclosed, adducts of alkyl linoleates with from 2 to 4 moles of an alkyl fumarate are valuable as plasticizers for vinyl chloride polymers in that they not only contribute very good low temperature flexibility properties to said polymers but also impart a degree of resistance to extraction by liquid hydrocarbons which is approxi mately twice that imparted to said polymers by using alkyl fumarate-alkyl oleate adducts. Thus, while the incorporation in polyvinyl chloride in a quantity of 40 percent by weight of an adduct of butyl oleate with 2 or more moles of a butyl fumarate results in a plasticized product from which 13.1% solids is extracted by kerosene, the use of the same proportion of an adduct of butyl linoleate with 2 or more moles of a butyl fumarate gives a plasticized polyvinyl chloride from which only 7.4% is kerosene extracted under the same test conditions. Unexpectedly, however, when there is employed in the polyvinyl chloride neither said butyl oleate-butyl fumarate adduct nor said butyl linoleate-butyl fumarate adduct but 40 percent by weight of an adduct of 2 or more moles of butyl fumarate with one mole of a tall oil unsaturated fatty acid fraction containing both oleic and linoleic acids, there is obtained a plasticized polyvinyl chloride from which only 1.8 percent of solids is extracted by kerosene under the same test conditions. The synergistic eifect demonstrated by said tall oil fatty acid adduct with respect to kerosene resistance is also noted in the volatility properties of the plasticized polyvinyl chlorides as measured by subjecting the plasticized material to aging or heating under standard conditions. While polyvinyl chloride plasticized with 40 percent by weight of said butyl fumarate-butyl oleate adduct has a volatility value of 3.9 percent and that con-' taining the same weight percent of said butyl fumaratebutyl linoleate adduct has a volatility value of 3.2 percent, that which has been plasticized with the same proportion of said butyl fumarate-tall oil fatty acid ester adduct has a volatility value of only 1.6 percent.

As examples of fumarates useful for the preparation of the present adducts from the linoleic or tall oil unsaturated fatty acid fraction may be mentioned the simple dialkyl fumarates such as methyl, ethyl, n-propyl, iso propyl, n-butyl, tert-butyl, n-amyl, isoamyl, n-hexyl, nheptyl, Z-ethylhexyl or n-octyl fumarate, etc., and the mixed dialkyl fumarates such as n-amyl methyl fumarate, n-butyl n-hexyl fumarate, ethyl Z-ethylhexylfumarate, etc.

The higher unsaturated fatty acid component is an alkyl ester of linoleic acid or of a tall oil unsaturated fatty acid fraction containing linoleic acid, e.g., a methyl, ethyl, n-propyl, n-butyl, tert-amyl, n-hexyl, n-heptyl, 2- ethylhexyl or n-octyl ester thereof. By tall oil fatty acid fraction as used herein is meant the unsaturated fatty acids remaining after the rosin acids and unsaponifiables in tall oil have been substantially completely removed. The tall oil fatty acid fraction will generally contain at least percent by weight of unsaturated fatty acids, from about 35 percent to about 60 percent of said unsaturated acids being linoleic acid.

In preparing the present adducts I prefer to operate as follows:

The fumarate and the linoleate or tall oil acid ester are mixed in a reaction vessel in proportions of from 2 to 4 moles of the fumarate per mole of higher ester, and the mixture is heated, usually at atmospheric pressures at temperatures of from 150 C. to 300 C. Pressures of below or above atmospheric may be employed. In some instances, especially when working with the higher esters, an inert, high-boiling diluent may be desirable. An inhibitor of polymerization, e.g., pyrogallol or tert-butylcatechol may or may not be employed. The reaction time may vary from, say, an hour to several days, a reaction time of, say, from 3 to 30 hours being recommended when it is desired to obtain a preponderant yield of products having a greater than 1:2 higher fatty esterfumarate ratio. The product is generally a viscous liquid which comprises a mixture of adducts of varying dicarboxy content and unreacted initial reagents. Any unreacted material may be readily recovered, e.g., by distillation.

The present adducts are stable, high-boiling materials which range from heavy to viscous liquids. They may be advantageously employed for a variety of technical uses, i.e., as intermediates for the preparation of polycarboxylic compounds to be employed for polyamide manufacture, as moisture-proofing agents, lubricant adjuvants, etc.

The present adducts are particularly valuable plasticizers for polyvinyl chloride and copolymers of at least 70 percent by weight of vinyl chloride and up to 30 percent by weight of an unsaturated monomer copolymerized therewith, for example, vinyl acetate, vinylidene chloride, etc. They impart great flexibility to vinyl chloride polymers at very low temperatures and they are compatible with such polymers and show no exudation of plasticizer even at plasticizer content of up to 50 percent. Although the quantity of plasticizer will depend upon the particular polymer to be plasticized and upon its molecular weight, it is generally found that compositions having from 5 percent to 50 percent by weight of the present adducts will, in most cases, be satisfactory for general utility. The good flexibility of the plasticized composition increases with increasing plasticizer concentration.

In evaluating plasticizer efficiency, use is made of the following empirical testing procedures:

C0mparibility.--Visual inspection of the plasticized composition is employed, incompatibility of the plasticizer with the polymer being demonstrated by cloudiness and exudation of the plasticizer.

Hardness-A standard instrument made by the Shore Instrument Company is used for this determination and expresses the hardness in units from 1 to 100. The hardness of a composition is judged by its resistance to the penetration of a standard needle applied to the composition under a standard load for a standard length of time.

Low temperature fiexibilily.Low temperature flexibility is one of the most important properties of elastomeric vinyl compositions. While many plasticizers will produce flexible compositions at room temperature the flexibility of these compositions at low temperatures may vary considerably, i.e., plasticized polyvinyl chloride compositions that are flexible at room temperature often become very brittle and useless at low temperatures. Low temperature flexibility tests herein employed are according to the Clash-Berg method. This method determines the torsional flexibility of a plastic at various temperatures. The temperature at which the vinyl composition exhibits an arbitrarily established minimum flexibility is defined as the low temperature flexibility of the composition. This value may also be defined as the lower temperature limit of the plasticized compositions usefulness as an elastomer.

Volatility-Just as a decrease in low temperature often results in decreased flexibility of a plasticized polymer composition so does a decrease in plasticizer concentration when caused by volatilization of the plasticizer. Hence, plasticizers which are readily volatilized from the plasticized compositon as a result of aging or heating are inefiicient because upon volatilization the plasticized compositions become stiff and hard. The test for plasticizer volatility herein employed is that described by the American Society for Testing Materials under the designation D-744-44T.

Water resistance.The amount of water absorption and the amount of leaching that takes place when the plasticized composition is immersed in distilled water for 24 hours is determined.

The invention is further illustrated but not limited by the following examples:

Example 1 This example describes a preparation of an adduct of butyl fumarate and the butyl ester of an unsaturated fatty acid fraction which will be hereinafter referred to as tall oil fatty acid. The tall oil fatty acid from which the presently used butyl ester was prepared is characterized by its manufacturer as follows.

A mixture consisting of 270.4 g. (0.8 mole) of the butyl ester of above-described tall oil fatty acid and 456 g. (2 moles) of butyl fumarate was charged to a flask equipped with stirrer, thermometer and reflux condenser and brought to a temperature of 240 C. and heating was continued in a nitrogen atmosphere for 5 hours during which time a solution consisting of 2.2 g. di-tertbutylcatechol in 12 g. of butyl fumarate was added at intervals to the heated reaction mixture. The refractive index of the reaction rose from an initial 21 1.4489 to 11 1.4594. Distillation of the reaction mixture to remove material boiling below a pot temperature of 240 C./1 mm. gave as residue 450 g. of the adduct of the tall oil fatty acid fraction with an average of 3 moles of butyl fumarate, 11 1.4665, and having a free acid content of 1.87% calculated as oleic acid, and an iodine number of 24.48, as compared with calculated value of 25 for the 1:3 ratio.

Example 2 A mixture consisting of 181.0 g. (0.8 mole) butyl fumarate, 135.2 g. (0.4 mole) of the butyl ester of tall oil unsaturated fatty acid fraction described in Example 1 and 1.8 g. of tert-butylcatechol was heated in a nitrogen atmosphere, with stirring, for 2 hours at a temperature of 250-251" C. The refractive index, 21 of the mixture rose from 1.4510 to 1.4564. Distillation of the resulting reaction mixture to remove material boiling below 200 C./1 mm. gave as residue 138 g. of the adduct of one mole of said tall oil ester with more than one mole of the fumarate, 11 1.4665, having a free acid content of 1.25% calculated as oleic acid.

Example 3 In this experiment no inhibitor of polymerization was used in preparing the adduct of butyl fumarate and the butyl ester of the tall oil unsaturated fatty acid fraction of Example 1.

A mixture consisting of 135.2 g. (0.4 mole) of said tall oil ester and 182.4 g. (0.8 mole) of said fumarate was heated at a temperature of 232 C. to 251 C. for 6 hours. The refractive index of the mixture rose from 21 1.4498 to 12 1.4572. Distillation of the resulting reaction mixture to remove material boiling below a pot temperature of 270 C./1 mm. gave as residue 135 g. of the adduct of 1 mole of said tall oil ester with more than one mole of the fumarate, 11 1.4650, having a free acid content of 0.40% calculated as oleic acid and a saponification equivalent of 178.

Example 4 To a reaction vessel equipped with mechanical stirrer, thermometer and a Dean-Stark trap carrying a reflux condenser, there was charged 134.7 g. (0.4 mole) of butyl linoleate, 353 g. (1.55 moles) of butyl fumarate, and about 13.8 g. of solution of inhibitor consisting of 1.8 g. of di-tert-butylcatechol in 12 g. (0.05 mole) of butyl fumarate. The linoleate-fumarate charge was brought to reflux in 30 minutes and hourly addition (approximately 2 g. each time) of inhibitor solution was started. Refluxing (240-242 C.) was continued for four hours; then, before adding more inhibitor solution, a 250 g. portion (A) of the mixture was removed from the reaction vessel. Addition of the inhibitor solution was resumed and refluxing continued for two hours. During the 6.0 hour total heating time, the refractive index of the reaction mixture rose from 1.4490 to 1.4581.

Distillation of portion (A) at a pressure of 1 mm. of Hg gave 78 g. of butyl fumarate, 22.6 g. of a fraction, B.P. 200-225" C./1 mm., n 1.4521, and 150 g. of residue (labelled Fraction 1), n;, 1.4637, having an iodine number of 36.22. The calculated iodine number of a -1 :1 butyl linoleate-butyl fumarate Diels-Alder adduct containing only one olefinic bond is 45; whereas that of a 1:2 butyl linoleate-butyl fumarate adduct having one olefinic double bond is 32.05. Accordingly, Fraction 1 is an adduct consisting predominantly of the 1:2 butyl linoleate-butyl fumarate adduct, with minor proportions of the 1:1 and probably some higher ratio adducts.

The material which had been treated for 6.0 hours was distilled at 1 mm. of Hg pressure to give 57 g. of butyl fumarate, 17.3 g. of a fraction, B.P. ZOO-225 C./1 mm., n 1.4535, and 169 g. of a residue (labelled Fraction 2), 11 1.4643, having an iodine number of 30.26. Since the calculated iodine number of a 1:2 butyl linoleate-butyl fumarate adduct is 32.05, Fraction 2 corresponds to a mixture of adducts consisting predominantly of the 1:2 and 1:3 butyl linoleate-butyl fumarate adducts.

Example 5 For purposes of comparison an adduct of butyl oleate and butyl fumarate was prepared as follows: A mixture consisting of 135.2 g. of butyl oleate and 350 g. of butyl fumarate was heated at a temperature of from 240-245" C. for 6 hours during which period there was gradually added to the heated reaction mixture a solution of 1.8

g. of di-tert-butylcatechol and 12 g of butyl fumarate. The refractive index, 21 rose from 1.4450 to 1.4520

during the heating period. Distillation of the resulting reaction mixture to remove material boiling below a pot temperature of 225 C./1 mm. of Hg gave as residue the adduct of one mole of butyl oleate with an average of more than 2 moles of butyl fumarate, 11 1.4605, a free acid content of 2.8%, and an iodine number 25.3.

Example 6 This example shows the volatility and low temperature flexibility properties of the butyl fumarate-tall oil ester adduct of Example 2, the butyl fumarate-linoleate adduct of Example 4 (Fraction 2) and the butyl furmarate-oleate adduct of Example 5.

Respective mixtures consisting of 60 parts of polyvinyl chloride and 40 parts by weight of either the adduct of Example 2 or the adduct of Example 5 were mixed on a rolling mill to a homogeneous blend. During the milling there was observed substantially no fuming and discoloration. Molded test specimens of the respective mixtures were clear and transparent and substantially colorless. Testing of the molded test specimens for low temperature flexibility, according to the testing procedures described above, gave a value of minus 28.1 C. for the test specimen containing the tall oil ester adduct of Example 2 as a plasticizer and a value of minus 27.0 C.

for the test specimen containing the oleate adduct of Example 5 as a plasticizer. Tests on the volatility characteristics of said molded test specimens according to the testing procedures described above gave a value of 1.6% for the specimen containing the tall oil ester adduct of Example 2 as a plasticizer, a value of 3.2% for the specimen containing the linoleate adduct of Example 4 (Fraction 2) as a plasticizer, and a value of 3.9% for the specimen containing the oleate adduct of Example 5 as a plasticizer, which results show that the adduct prepared from butyl fumarate and the butyl ester of tall oil fatty acid fraction shows more than twice the resistance to heat and aging than does the adduct prepared from butyl fumarate and butyl oleate.

Example 7 This example shows the kerosene resistance of polyvinyl chloride which had been plasticized with the tall oil ester adduct of Example 1, the linoleate adduct of Example 4 (Fraction 2) or the oleate adduct of Example 5.

Respective mixtures consisting of 60 parts of polyvinyl chloride and 40 parts by weight of one of said adducts were mixed on a rolling mill to a homogenous blend. Test specimens of the milled mixtures having a diameter of 2" and a thickness of 40 mils were molded from the compounded mixtures and then suspended in a 50 C. oven for a 3 hour conditioning period to eliminate water. They were then cooled and weighed. The conditioned samples were immersed in 400 ml. of kerosene for a period of 24 hours at a temperature of 20 C. The samples were then removed from the kerosene, blotted dry and suspended in a forced-draft oven at C. for 4 hours. After cooling and weighing the treated samples, the percent loss in weight of the sample containing the tall oil ester adduct of Example 1 as a plasticizer was found to be 1.8%, the loss in weight of the sample containing the linoleate adduct of Example 4 (Fraction 2) as a plasticizer was found to be 7.4%, and the loss in weight of the sample containing the oleate adduct of Example 5 was found to be 13.1%.

Instead of the adducts of dibutyl fumarate and butyl linoleate, adducts prepared from other fumarates and other linoleates or other alkyl esters of tall oil unsaturated fatty acid fractions give similarly good results as polyvinyl chloride plasticizers. Thus, by employing 40 parts by weight of the adduct of methyl or ethyl fumarate and 2-ethylhexyl linoleate or the adduct of n-propyl or amyl fumarate and the ethyl ester of tall oil unsaturated fatty acid fraction with 60 parts by weight of a vinyl chloridevinyl acetate copolymer knovm to the trade as Vinylite there are obtained clear, colorless, compositions of very good flexibility and stability.

While the above examples show only compositions in which the ratio of plasticizer to polymer content is 40:60, this ratio being employed in order to get comparable efliciencies the content of adduct to polyvinyl chloride may be widely varied, depending upon the properties desired in the final product. For many purposes, a plasticizer content of, say, from only 10 percent to 20 percent is preferred. The present adducts are compatible with polyvinyl chloride over wide ranges of concentrations, up to 50 percent of esters based on the total weight of the plasticized composition yielding desirable products.

Although the invention has been described particularly with reference to the use of the present adducts as plasticizers for polyvinyl chloride, these adducts are advantageously employed also as plasticizers for copolymers of vinyl chloride, for example, the copolymers of vinyl chloride with vinyl acetate, vinylidene chloride, etc. Preferably, such copolyrners have a high vinyl chloride content, i.e., a vinyl chloride content of at least 70' percent by weight of vinyl chloride and up to 30 percent by weight of the copolymerizable monomer.

The plasticized polyvinyl halide compositions of the present invention have good thermal stability; however, for many purposes, it may be advantageous to use known stabilizers in the plasticized compositions. Inasmuch as the present polycarboxylates are substantially unreactive with the commercially available heat and light stabilizers which are commonly employed with polyvinyl chloride or copolymers thereof, the presence of such materials in the plasticized products does not impair the valuable properties of the adducts. The present polycarboxylates are of general utility in softening vinyl chloride polymers. They may be used as the only plasticizing component in a compounded vinyl chloride polymer or they may be used in conjuction with other plasticizers.

This is a division of my copending applications, Serial Number 408,985, filed February 8, 1954, and now abandoned, and Serial Number 540,645, filed October 14, 1955, and now issued as Patent No. 2,938,044, dated May 24, 1960.

What I claim is:

1. A resinous composition consisting essentially of a polymer selected from the class consisting of polyvinyl chloride and copolymers of vinyl chloride and an ethylenically unsaturated monomer copolymerizable therewith, said polymer being plasticized with an olefinically unsaturated adduct in which from 2 to 4 moles of an alkyl fumarate having from 1 to 8 carbon atoms in the alkyl radical are individually combined at the acid portion of an alkyl ester of a tall oil unsaturated fatty acid fraction wherein the alkyl radical has from 1 to 8 carbon atoms, said tall oil unsaturated fatty acid fraction containing at least 90% by weight of unsaturated fatty acids from about 35 to 60% of said acids being linoleic acid, said adduct being from 5 to percent of the weight of the composi alkyl radical has from 1 to 8 carbon atoms, said tall oil unsaturated fatty acid fraction containing at least 90% by weight of unsaturated fatty acids from about 35 to of said acids being linoleic acid, said adduct being from 5 to 50 percent of the weight of the composition.

3. A resinous composition consisting essentially .of

polyvinyl chloride plasticized with an olefinically unsaturated adduct in which from 2 to 4 moles of an alkyl fumarate having from 1 to 8 carbon atoms in the alkyl radical are individually combined at the acid portion of an alkyl ester of a tall oil unsaturated fatty acid fraction wherein the alkyl radical has from 1 to 8 carbon atoms,

said tall oil unsaturated fatty acid fraction containing at least by weight of unsaturated fatty acids from about 35 to 60% of said acids being linoleic acid, said adduct being from 5 to 50 percent of the weight of thecomposition.

4. A resinous composition consisting essentially of polyvinyl chloride plasticized with an olefinically unsaturated adduct in which from 2 'to 4 moles of butyl fumarate are individually combined at the acid portion of the butyly ester of a tall oil unsaturated fatty acid fraction, said tall oil unsaturated fatty acid fraction containing at least 90% by weight of unsaturated fatty acids from about 35 to 60% of said acids being linoleic acid, said adduct being from 5 to 50 percent of the weight of the composition.

References Cited in the file of this patent t UNITED STATES PATENTS Butler Aug. 24, 1954 Dazzi Oct. 25, 1960

Claims (1)

1. A RESINOUS COMPOSITION CONSISTING ESSENTIALLY OF A POLYMER SELECTED FROM THE CLASS CONSISTING OF POLYVINYL CHLORIDE AND COPOLYMERS OF VINYL CHLORIDE AND AN ETHYLENICALLY UNSATURATED MONOMER COPOLYMERIZABLE THEREWITH, SAID POLYMER BEING PLASTICIZED WITH AN OLEFINICALLY UNSATURATED ADDUCT IN WHICH FROM 2 TO 4 MOLES OF AN ALKYL FUMARATE HAVING FROM 1 TO 8 CARBON ATOMS IN THE ALKYL RADICAL ARE INDIVIDUALLY COMBINED AT THE ACID PORTION OF AN ALKYL ESTER OF A TALL OIL UNSATURATED FATTY ACID FRACTION WHEREIN THE ALKYL RADICAL HAS FROM 1 TO 8 CARBON ATOMS, SAID TALL OIL UNSATURATED FATTY ACID FRACTION CONTAINING AT LEAST 90% BY WEIGHT OF UNSATURATED FATTY ACIDS FROM ABOUT 35 TO 60% OF SAID ACIDS BEING LINOLEIC ACID, SAID ADDUCT BEING FROM 5 TO 50 PERCENT OF THE WEIGHT OF THE COMPOSITION.