the compounds of the present invention are prepared by the following sequence : the mole ratio of the reaction is set so that there is always an excess of hydroxyl group relative to carboxyl group in the polyester . the preferred ratio is between 3 hydroxyl groups to 1 carboxyl group , to 2 hydroxyl groups to 1 carboxyl groups . when the materials are added together they are heated to 120 - 150 ° c . and held for several hours . during this time the anhydride opens up and a carboxy ester is formed . in order to simplify the description of the reaction we have shown succinic anhydride as the only reactant . in reality the alkenyl succinic anhydride is also included to make a polymer with the desired hydrophobicity and surfactant property . r ′ is used in the reaction below and it is a mixture of h and r . that is the anhydride used to make the product is a mixture of alkenyl succinic anhydride and succinic anhydride . while we show the structure as having reacted at the center hydroxyl , there is actually a mixture of mono isomers and a relatively low concentration of di product , resulting in an oligomeric product . as the temperature is increased to 180 - 190 ° c . the carboxyl groups react with to make polyester . as the reaction proceeds the polyester continues to increase in molecular weight and the viscosity of the product increases . additionally , and critically importantly to the reaction , the product becomes clear as the alkenyl succinic anhydride is incorporated by reaction into the polyester backbone . r ′ is a mixture of h , alkenyl and alkyl having 10 to 20 carbon atoms ; the present invention is directed to a polymer made by the esterification reaction of r is selected from alkyl , alkenyl and mixtures of thereof having 10 to 20 carbon atoms . in a preferred embodiment r is alkyl having 10 to 20 carbon atoms in another preferred embodiment r is alkenyl having 10 to 20 carbon atoms . in a preferred embodiment the mole ratio of hydroxyl to carboxyl in the reactants ranges from 3 : 1 to 2 : 1 . in a more preferred embodiment the mole ratio of hydroxyl to carboxyl in the reactants is 3 : 1 . in a preferred embodiment r ′ is a mixture of r and h . in a preferred embodiment r ′ is a mixture of r and h , wherein the ratio of r to h ranges from 1 : 5 to 1 : 20 . in a preferred embodiment r ′ is a mixture of r and h , wherein the ratio of r to h ranges from 1 : 10 to 1 : 15 . glycerin is an item of commerce confirming to the following structure ; it is available from a variety of sources including proctor and gamble . it is available from a variety of sources including sigma aldrich corp . st . louis , mo . r is selected from alkyl , alkenyl and mixtures of thereof having 10 to 20 carbon atoms . the products as prepared by reaction of alpha olefin and maleic anhydride result in a alkenyl compound alkyl and alkenyl succinic anhydrides are commercially available from a variety of sources including humphery inc . to 100 grams of glycerin is added the specified number of grams of succinic anhydride , the specified number of grams of the specified of alkenyl succinic anhydride ( example 3 - 10 ). the reaction mass is heated to 120 - 130 ° c . as reaction reaches 120 ° c . the batch becomes homogeneous . the temperature is held for three hours . the temperature is increased to 180 - 190 ° c . water is distilled off and the reaction mass becomes thick . the batch clears as the reaction proceeds and the acid value decreases to theoretical . the amount of water distilled off is used to calculate the “ n ” value . the products as prepared are viscous yellow liquids . they are subsequently cut with water to a solids level of between 25 and 50 % by weight . the products of the present invention are high foaming compounds that provide detergency and a very cosmetically appealing skin feel . the foam characteristics are determined by ( a ) alkyl to hydrogen ratio and ( b ) the hydroxyl to carboxyl value . the higher the alkyl value , the more hydrophobic the product . the foam level peaks as the percentage of alkyl or alkenyl succinate increases to around 10 % by weight . above this the foam decreases and improved conditioning is noted . as the percentage by weight of alkyl or alkenyl succinate increases above 25 % by weight a water insoluble product is encountered . as the hydroxyl to carboxyl ratio is increased from 2 : 1 to 3 : 1 water solubility increases and humectancy is observed . the foam decreases as the hydroxyl to carboxyl ratio increases . while the illustrative embodiments of the invention have been described with particularity , it will be understood that various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the spirit and scope of the invention . accordingly , it is not intended that the scope of the claims appended hereto be limited to the examples and descriptions set forth hereinabove but rather that the claims be construed as encompassing all the features of patentable novelty which reside in the present invention , including all features which would be treated as equivalents thereof by those skilled in the art to which the invention pertains .
the invention discloses a series of glycerin / succinate / alkyl succinate polyesters . these materials are high foaming detergents useful in the formulation of biodegradable , polyoxyalkylene free , cosmetic and personal care products .