Uses and compositions

Abstract

A composition for treating a keratinous material growing on a body, wherein the composition comprises one or more esters being the reaction product of a cyclic anhydride and a polyol. Preferably, the

Description

The appearance, condition and cleanliness of their hair is of great significance to many people. For example, frizziness of hair is a concern, especially for people who have wavy or curly hair and / or are in humid conditions. Similarly, many people are concerned with the appearance, condition and cleanliness of the hair and of their animals (including pets). People are also concerned with the appearance of their nails, and with the appearance of the nails, horns, claws or hooves of their animals. There is therefore a vast array of personal care products available, for both humans and animals (including pets), offering a wide range of benefits to hair, nails, horns, claws and hooves. These products contain many different components, including silicone compounds to impart lubrication and / or softening properties. However changing requirements, for example due to changing fashion trends, new interests in animal care and technological developments for example in hair styling appliances means that there is a continuing need for different and improved personal care compositions (such as hair care compositions). Furthermore the environmental impact of chemicals used in personal care compositions is of increasing importance to consumers. For example, there are a number of disadvantages associated with the use of silicone compounds, including their low biodegradability, which has led to environmental concerns. It is thus an object of the invention to provide means for treating (including enhancing) at least one property of a keratinous material, such as hair. It is another object of the invention to provide compositions (such as hair care compositions) that are more environmentally acceptable and / or biodegradable whilst having equal or improved properties compared to known compositions (such as hair care compositions). Summary of the Invention According to aspects of the present invention, there is provided a method, use, composition and packaged keratinous material treatment product as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and from the description which follows. The inventors have identified that certain ester compounds can treat and / or enhance at least one property of a keratinous material, whilst also being environmentally acceptable and / or biodegradable. According to a first aspect of the invention, there is provided a method of treating a keratinous material growing on a body, the method comprising contacting the keratinous material with an ester compound, wherein the ester compound is the reaction product of reactants comprising one or more first reactants and one or more second reactants, wherein the or each first reactant is a cyclic anhydride and the or each second reactant is a polyol. According to a second aspect of the present invention there is provided a use of an ester compound to treat a keratinous material growing on a body, wherein the ester compound is the reaction product of reactants comprising one or more first reactants and one or more second reactants, wherein the or each first reactant is a cyclic anhydride and the or each second reactant is a polyol. According to a third aspect of the invention, there is provided a composition for treating a keratinous material growing on a body, wherein the composition comprises one or more ester compounds, and wherein the or each ester compound is the reaction product of reactants comprising one or more first reactants and one or more second reactants, wherein the or each first reactant is a cyclic anhydride and the or each second reactant is a polyol. According to a fourth aspect of the invention, there is provided a packaged keratinous material treatment product comprising packaging, a composition housed in the packaging and instructions for use of the composition in the treatment of a suitable keratinous material growing on a body, wherein the composition comprises one or more ester compounds, and wherein the or each ester compound is the reaction product of reactants comprising one or more first reactants and one or more second reactants, wherein the or each first reactant is a cyclic anhydride and the or each second reactant is a polyol. Other features of the invention will be apparent from the dependent claims, and from the description which follows. Features described in relation to the second, third and fourth aspects may have any of the suitable features and advantages described in relation to the first aspect. Detailed Description of the Invention Unless otherwise stated, the following terms used in the specification and claims have the meanings set out below. The terms “alkyl” and “alkylene” include both straight and branched chain alkyl and alkylene groups respectively unless otherwise stated. References to individual alkyl groups such as “propyl” are specific for the straight chain version only and references to individual branched chain alkyl groups such as “isopropyl” are specific for the branched chain version only. For example, “C3-30 alkyl” includes C6-24 alkyl, Ce-s alkyl, propyl, isopropyl and t-butyl. The term “alkenyl” includes both straight and branched chain alkenyl groups. References to individual alkenyl groups such as “propenyl” are specific for the straight chain version only and references to individual branched chain alkenyl groups such as “isopropenyl” are specific for the branched chain version only. For example, “C3-30 alkenyl” includes C6-24 alkenyl, Ce-s alkenyl, propenyl and isopropenyl. Herein C3-30 means a group having from 3 to 30 carbons atoms therein, for example having 3, 4, 5 etc up to 30 carbon atoms. The term "hydrocarbyl" is used in its ordinary sense, which is well-known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of the molecule and having predominantly hydrocarbon character. As used in the specification and the appended claims, the singular forms "a", "an," and "the" include both singular and plural referents unless the context clearly dictates otherwise. Throughout this specification, the term “comprising” or “comprises” means including the component(s) specified but not to the exclusion of the presence of other components. The term “consisting essentially of’ or “consists essentially of’ means including the components specified but excluding other components except for components added for a purpose other than achieving the technical effect of the invention. The term “consisting of’ or “consists of’ means including the components specified but excluding other components. Whenever appropriate, depending upon the context, the use of the term “comprises” or “comprising” may also be taken to include the meaning “consists essentially of’ or “consisting essentially of’, and also may also be taken to include the meaning “consists of’ or “consisting of’. As used herein, unless otherwise expressly specified, all numbers such as those expressing values, ranges, amounts of percentages may be read as if prefaced by the word “about”, even if the term does not expressly appear. The recitation of numerical ranges by endpoints includes all integer numbers and, where appropriate, fractions subsumed within that range (e.g. 1 to 5 can include 1,2,3,4 when referring to, for example, a number of elements, and can also include 1.5,2,2.70 and 3.80, when referring to, for example, measurements). The recitation of end points also includes the end point values themselves (e.g. from 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical range recited herein is intended to include all sub-ranges subsumed therein. The optional features set out herein may be used either individually or in combination with each other where appropriate and particularly in the combinations as set out in the accompanying claims. The optional features for each exemplary aspect of the invention, as set out herein are also applicable to any other aspects or exemplary aspects of the invention, where appropriate. In other words, the skilled person reading this specification should consider the optional features for each aspect or embodiment of the invention as interchangeable and combinable between different aspects of the invention. As used herein, the term "and / or," when used in a list of two or more items, means that any one of the listed items can be employed by itself or any combination of two or more of the listed items can be employed. For example, if a list is described as comprising group A, B, and / or C, the list can comprise A alone; B alone; C alone; A and B in combination; A and C in combination, B and C in combination; or A, B, and C in combination. The term “reactant” is used herein to refer to a compound comprising at least one reactive functional group. As reported herein, the number average molecular weight was determined by gel permeation chromatography using a polystyrene standard according to ASTM D6579-11 (“Standard Practice for Molecular Weight Averages and Molecular Weight Distribution of Hydrocarbon, Rosin and Terpene Resins by Size Exclusion Chromatography”. UV detector; 254 nm, solvent: unstabilised THF, retention time marker: toluene, sample concentration: 2mg / ml). According to a first aspect of the invention, there is provided a method of treating a keratinous material growing on a body, the method comprising contacting the keratinous material with an ester compound, wherein the ester compound is the reaction product of reactants comprising one or more first reactants and one or more second reactants, wherein the or each first reactant is a cyclic anhydride and the or each second reactant is a polyol. According to a second aspect of the present invention there is provided a use of an ester compound to treat a keratinous material growing on a body, wherein the ester compound is the reaction product of reactants comprising one or more first reactants and one or more second reactants, wherein the or each first reactant is a cyclic anhydride and the or each second reactant is a polyol. Suitable features of the first and second aspects will now be described. The method and use of the first and second aspects are for treating a keratinous material growing on a body, such as a human or animal body. The ester compound as disclosed herein may be used to treat any suitable keratinous material. Preferably the keratinous material comprises keratinous fibres. The keratinous material may, for example, be hair, nails, horns, claws or hooves. Preferably the keratinous material is hair. The hair may be human or animal hair. The hair may be scalp hair, eyebrows, eyelashes, beard hair, or body hair, for example on a human. The hair may be under-hair, wool or fur, for example on an animal. The hair may have been artificially coloured, such as by being dyed, bleached or pigmented. The hair may be human hair. The hair may be textured hair, such as Afro-Caribbean hair. Thus, the method of the first aspect may be a method of treating human hair growing on the body. The use of the second aspect may be a use to treat human hair growing on the body. The hair may be animal hair. Thus, the method of the first aspect may be a method of treating animal hair growing on the body. The use of the second aspect may be a use to treat animal hair growing on the body. The method or use of the first or second aspect may be applied to wet or dry keratinous material, especially hair. References herein to treating a keratinous material, especially hair, are intended to refer to changing, for example by providing a beneficial effect to, and especially by enhancing, at least one property of a keratinous material (especially hair). References to changing, benefiting or enhancing a property of a keratinous material are intended to mean as compared to otherwise identical keratinous material that has not been treated with the ester compound or composition as disclosed herein. Thus, the method of the first aspect preferably provides a benefit to the keratinous material treated. Suitably the method enhances at least one property of the keratinous material that is treated according to the method. Preferably, the method of the first aspect is a method of treating hair that provides a beneficial effect to the hair. Suitably it enhances at least one property of the hair. Thus, the use of the second aspect preferably provides a benefit to the keratinous material treated. Suitably the use enhances at least one property of the keratinous material that is treated according to the use. Preferably, the use of the second aspect is a use to treat hair that provides a beneficial effect to the hair. Suitably it enhances at least one property of the hair. The method and use of the first and second aspects may change, provide a beneficial effect to or enhance any suitable property of the keratinous material (especially hair). The change, such as the benefit or enhancement, may be detectable by a visual inspection and / or may be a measurable change according to methods known in the art. The property may be a conditioning effect. For example, the property of the keratinous material (especially hair) that may be changed, beneficially affected or enhanced may be one or more of the following: • reduction in frizziness • shine • gloss • softness • silkiness • moisturise level • thermal durability • protection against damage • strength • combability • smoothness • drying time • colour retention For example, the property of the keratinous material (especially hair) that may be changed, beneficially affected or enhanced may be one or more of the following: • reduction in frizziness • shine • gloss • softness • silkiness • moisturise level • thermal durability • protection against damage • strength • combability • smoothness • drying time Preferably, the property of the keratinous material (especially hair) that may be changed, beneficially affected or enhanced may be one or more of the following: • reduction in frizziness • softness • silkiness • moisturise level • thermal durability • protection against damage • strength • combability • smoothness • drying time • colour retention Most preferably, the property of the keratinous material (especially hair) that may be changed, beneficially affected or enhanced may be one or more of the following: • reduction in frizziness • combability It has been surprisingly found that the method and use of the first and second aspects can significantly change, benefit or enhance the keratinous material (especially hair). This change, benefit or enhancement may be temporary, permanent or semi-permanent. The change, benefit or enhancement may prevent an undesirable property occurring in the keratinous material and / or may reduce the occurrence of an undesirable property. Suitably, the method and use of the first and second aspects may provide a temporary change, benefit or enhancement to a property of the keratinous material (especially hair). A temporary change in the property of the keratinous material (especially hair) may be due to the ester compound as defined herein coating the surface of the keratinous material (especially hair) but forming a weak interaction such that the ester compound can be easily washed or brushed away. In some preferred embodiments the method and use of the first and second aspects may provide a longer lasting change, benefit or enhancement to the keratinous material (especially hair), for example a wash-durable benefit. The method and use of the first and second aspects may change, benefit or enhance the keratinous material (especially hair) by providing a conditioning effect thereto. Any suitable conditioning effect may be provided. Examples of suitable conditioning effects may include shine, gloss, softness, silkiness, moisture level, combability and / or smoothness (especially softness, silkiness, moisture level, combability and / or smoothness). The method and use of the first and second aspects may change, benefit or enhance the keratinous material (especially hair) by providing a reduction in frizziness thereto, i.e. by providing an anti-frizz effect. References to an anti-frizz effect are intended to mean that frizz in the keratinous material (especially hair) is reduced or removed. References to keratinous material (such as hair) that is frizzy means that the material (such as hair) contains short strands that stick up and project away from the main body of the material (such as hair) and / or that the material (such as hair) contains strands, for example of wavy or curly material (such as hair), that do not align with others or form a defined wave or curl. The anti-frizz effect may be detectable by a visual inspection and / or may be measurable using well known methods in the art (for example as disclosed herein, such as in the examples section). The method and use of the first and second aspects may provide a reduction in frizziness of at least 55%, preferably at least 75%, for example at least 95% after 24 hours as measured according to the test method disclosed in the examples section herein. The method and use of the first and second aspects may change, benefit or enhance the keratinous material (especially hair) by providing improved shine or gloss thereto. Rating systems for assessing shine and gloss are known in the art. A suitable system to calculate shine in a reproducible manner is the Reich-Robbins lustre value. The method and use of the first and second aspects may benefit the keratinous material (especially hair) by providing improved softness thereto. The softening may be provided by depositing the ester compound onto the keratinous material (especially hair). Suitable methods for assessing the softness of the keratinous material are known in the art. The method and use of the first and second aspects may benefit the keratinous material (especially hair) by providing improved silkiness thereto. The method and use of the first and second aspects may benefit the keratinous material (especially hair) by providing improved moisture levels (or moisturisation) thereto. The method and use of the first and second aspects may benefit the keratinous material (especially hair) by providing improved thermal durability thereto. The method and use of the first and second aspects may benefit the keratinous material (especially hair) by providing improved combability thereto. Combability may be measured using a texture analyser, preferably using a texture analyser as described in the Examples. The method and use of the first and second aspects may benefit the keratinous material (especially hair) by providing protection to the keratinous material against damage. For example the method and use of the first and second aspects may protect against damage from heat or sunlight (for example by providing UV stability or protection). The method and use of the first and second aspects may benefit the keratinous material (especially hair) by providing improved strength thereto. The method and use of the first and second aspects may change, benefit or enhance the keratinous material (especially hair) by providing improved smoothness thereto. Rating systems for assessing smoothness are known in the art. The method and use of the first and second aspects may change, benefit or enhance the keratinous material (especially hair) by reducing the drying time of the keratinous material (especially hair). Rating systems for drying time are known in the art. Drying time may be measured as described in US 2014 / 140947 A1. Suitably, drying time may be determined by measuring the time needed to evaporate at least 85 wt% (for example 98 wt%) of added water on a swatch of pre-cleaned keratinous material (especially hair) when subjected to a preselected amount of heat (for example, 50°C). The swatch of keratinous material is suitably weighed when dry, after being submerged in water, and at regular intervals (for example, every 15 minutes) while being heated. The method and use of the first and second aspects may benefit the keratinous material (especially hair) by providing improved colour retention (i.e. combating colour loss). The method of the first aspect involves contacting the keratinous material (especially hair) with an ester compound, wherein the ester compound is the reaction product of reactants comprising one or more first reactants and one or more second reactants, wherein the or each first reactant is a cyclic anhydride and the or each second reactant is a polyol. The keratinous material (especially hair) may be wet or dry when contacted with the ester compound. Suitably the ester compound is applied to the keratinous material (especially hair) and spread across the surface of the keratinous material (especially hair). Preferably when the keratinous material is hair, the ester compound may be rubbed into the hair and / or it may be combed through the hair. The ester compound may be contacted with the keratinous material (especially hair) permanently or for a limited period of time, after which it may be removed from the keratinous material (especially hair) using any suitable means. Suitably the ester compound may be rinsed from the keratinous material (especially hair) using warm water. In some embodiments the ester compound may be contacted with the keratinous material (especially hair), spread throughout and then immediately removed. The method of the first aspect may involve contacting the keratinous material (especially hair) with an ester compound or composition as defined herein once or more than once. The method of the first aspect may involve contacting the keratinous material (especially hair) with an ester compound as defined herein wherein the ester compound is provided as a component of a composition, such as a composition for treating a keratinous material (especially hair). The method or use of the first aspect may involve heating the keratinous material (especially hair). Such a heating step may involve commonly used heating techniques such as blow drying, or using tongs, straighteners, curlers or hoods etc. For the avoidance of doubt, the method and use of the first and second aspects are cosmetic. They are not medical or therapeutic. According to a third aspect of the invention, there is provided a composition for treating a keratinous material growing on a body, wherein the composition comprises one or more ester compounds, and wherein the or each ester compound is the reaction product of reactants comprising one or more first reactants and one or more second reactants, wherein the or each first reactant is a cyclic anhydride and the or each second reactant is a polyol. The composition of the third aspect is suitably a cosmetic composition. Suitably, the method of the first aspect involves contacting the keratinous material with the composition of the third aspect. Thus preferred features of the ester compound apply equally to the first and third aspects. According to a fourth aspect of the invention, there is provided a packaged keratinous material treatment product comprising packaging, a composition housed in the packaging and instructions for use of the composition in the treatment of a suitable keratinous material growing on a body, wherein the composition comprises one or more ester compounds, and wherein the or each ester compound is the reaction product of reactants comprising one or more first reactants and one or more second reactants, wherein the or each first reactant is a cyclic anhydride and the or each second reactant is a polyol. Suitably, the composition comprised in the product of the fourth aspect is the composition of the third aspect. The product of the fourth aspect is suitably a cosmetic product. The ester compound as used herein (i.e. in relation to the method, use, composition and product of the first, second, third and fourth aspects) is the reaction product of reactants comprising one or more first reactants and one or more second reactants as defined herein. In other words, the ester compound may be obtainable or obtained by reacting reactants comprising one or more first reactants and one or more second reactants as defined herein. The ester compound as used herein may be the reaction product of reactants consisting essentially of or consisting of one or more first reactants and one or more second reactants as defined herein. In other words, the ester compound may be obtainable or obtained by reacting reactants consisting essentially of or consisting of one or more first reactants and one or more second reactants as defined herein. The first and second reactants may be reacted in any suitable molar ratio to make the ester compound, as would be appreciated by a person skilled in the art. The first and second reactants may be reacted in a molar ratio of from 1:10 to 10:1, preferably from 1:6 to 6:1, for example from 1:3 to 3:1. Preferably, the first and second reactants may be reacted in a molar ratio of 1:1. Ratios refer to the total amounts of first reactants or second reactants if more than one first reactant or second reactant is present. The ester compound may be prepared by any suitable method, as would be known to persons skilled in the art. Suitably, the ester compound is not in a solid form. For example, the ester compound is preferably in the form of a liquid or gel, preferably a liquid. Suitably, the ester compound herein that is the reaction product of reactants comprising one or more first reactants and one or more second reactants is substantially free or free of crosslinking. References herein to a reaction product of reactants comprising the first and second reactants are intended to refer to a product of the reaction of reactants comprising the first and second reactants conducted in any suitable manner. For example, the reaction may occur between the first and second reactants in the absence of other reactant(s) or may occur in the presence of other reactant(s). The or each of the one or more first reactants used to make the ester compound is a cyclic anhydride. Mixtures of two or more different first reactants (i.e. different cyclic anhydrides) may be used to make the ester compound. Any suitable cyclic anhydride may be used to make the ester compound, as would be understood by the person skilled in the art. By the term cyclic anhydride we mean a compound (or reactant) that comprises at least one anhydride group that is contained within a ring structure. For example, the ring structure that contains the anhydride group may comprise from 4 to 8 atoms, which atoms are typically carbon and oxygen. The ring structure that contains the anhydride group may be saturated or partially unsaturated (and is preferably saturated). The cyclic anhydride compound may typically comprise more than 8 atoms. For example, suitable cyclic anhydrides may include one or more of an anhydride of formula (I), of formula (II) and of formula (III): wherein in formula (I) R1 and R2 are each independently selected from hydrogen, an alkyl group and an alkenyl group, or R1 and R2 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group; in formula (II) R3 and R4 are each independently selected from hydrogen, an alkyl group and an alkenyl group, or R3 and R4 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group; and in formula (III) X is CR9R10, O, S, or NR11; R5, R6, R7, R8, R9, R10, and R11 are each independently selected from hydrogen, an alkyl group and an alkenyl group, and / or any of R5, R6, R7, R8, R9, R10, and R11 together with the atoms to which they are attached represent an optionally substituted cyclic group. Cyclic anhydrides of formula (I) are preferred. X may suitably be CR9R10, O, or S. Preferably, X is CR9R10. When any of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 represents an alkyl group or an alkenyl group, the or each alkyl or alkenyl group may be branched or unbranched. The or each alkyl group may contain from 1 to 30 carbon atoms and the or each alkenyl group may contain from 2 to 30 carbon atoms. Preferably, the or each alkyl or alkenyl group may contain 6 or more carbon atoms. For example, the or each alkyl or alkenyl group may contain from 6 to 30, such as from 8 to 24, carbon atoms (i.e. may be a Ce-30, such as a Cs-24, alkyl or alkenyl group). When any of R1 and R2, or R3 and R4, orR5, R6, R7, R8, R9, and R10 represents an alkenyl group, the alkenyl group may be a branched alkenyl group, such as a tetrapropenyl group or a polyisobutenyl group. When any of R1 and R2, or R3 and R4, orR5, R6, R7, R8, R9, and R10 represents an alkenyl group, the alkenyl group may be a polyisobutenyl group. The polyisobutenyl group (when present) suitably has a number average molecular weight of from 100 to 2000, preferably from 100 to 1000, for example 260 or 550. The cyclic anhydride may be a polyisobutenyl succinic anhydride, for example wherein the polyisobutenyl group has a number average molecular weight of 260 or 550. When any of R1 and R2, or R3 and R4, orR5, R6, R7, R8, R9, and R10 represents an alkenyl group, the alkenyl group may be derived from a terminal olefin or an internal olefin. For example, the cyclic anhydride monomer may be an alkenyl substituted succinic anhydride prepared by the reaction of an alkene with maleic anhydride, wherein the alkene is a terminal olefin or an internal olefin. In some embodiments the alkenyl group may be derived from a terminal olefin. The term terminal olefin is used to refer to alkene compounds having a predominantly terminal double bond. Such compounds are also commonly described as terminal alkenes. Terminal double bonds terminate in a =CH2 group and may either be at the a-position or may be vinylidene groups. The terminal olefin is preferably an a-olefin. Examples of suitable terminal olefins include C15-18 terminal olefin and Cie terminal olefin. In some preferred embodiments the alkenyl group is derived from an internal olefin. The term internal olefin is used to refer to alkene compounds in which the alkene groups are predominantly not terminal. Examples of suitable internal olefins include C12 internal olefin, C15-18 internal olefin, C16 internal olefin and C18 internal olefin. The internal olefin is a p or higher olefin, such as a p-olefin. Internal olefins are sometimes known as isomerised olefins and may be prepared by isomerisation of an a-olefin. Typically, terminal olefins and internal olefins may be provided as a mixture of isomers. Suitably at least 70 mol%, such as at least 80 mol%, preferably at least 90 mol%, for example at least 95 mol% of the double bonds in terminal olefins are terminal double bonds. Suitably at least 70 mol%, such as at least 80 mol%, preferably at least 90 mol%, for example at least 95 mol% of the terminal double bonds in the terminal olefins are at the a-position (i.e. they are a-alkene groups). Suitably at least 70 mol%, such as at least 80 mol%, preferably at least 90 mol%, for example at least 95 mol% of the double bonds in internal olefins are non-terminal double bonds. Suitably, one of R1 and R2, R3 and R4, orR5, R6, R7, R8, R9, R10, and R11 may be an alkyl group or an alkenyl group (such as an alkenyl group derived from a terminal olefin or an internal olefin, preferably an internal olefin) and the other (or others) may be hydrogen. Examples of cyclic anhydride reactants of the formula (I), (II) or (III) wherein any of R1 and R2, R3 and R4, orR5, R6, R7, R8, R9, R10, and R11 represents hydrogen or a Ce-3o, such as a Cs-24, branched or unbranched alkyl or alkenyl group include succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), tetrapropenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, nonenyl succinic anhydride, C20-24 alkenyl succinic anhydride, C15-18 internal olefin-derived alkenyl succinic anhydride, C16 internal olefin-derived alkenyl succinic anhydride, C16 terminal olefin-derived alkenyl succinic anhydride, maleic anhydride and glutaric anhydride. The cyclic anhydride reactants of the formula (I), (II) or (III) wherein any of R1 and R2, R3 and R4, orR5, R6, R7, R8, R9, R10, and R11 represents hydrogen or a C6-30, such as a Cs-24, branched or unbranched alkyl or alkenyl group may be selected from succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), tetrapropenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, nonenyl succinic anhydride, C20-24 alkenyl succinic anhydride, maleic anhydride and glutaric anhydride. The cyclic anhydride reactants of the formula (I), (II) or (III) wherein any of R1 and R2, R3 and R4, orR5, R6, R7, R8, R9, R10, and R11 represents hydrogen or a C6-30, such as a Cs-24, branched or unbranched alkyl or alkenyl group may preferably be selected from dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), tetrapropenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, nonenyl succinic anhydride, C20-24 alkenyl succinic anhydride, and glutaric anhydride. The cyclic anhydride reactants are preferably selected from C15-18 internal olefin-derived alkenyl succinic anhydride, C16 internal olefin-derived alkenyl succinic anhydride, and C16 terminal olefin-derived alkenyl succinic anhydride. When any of R1 and R2, or R3 and R4, orR5, R6, R7, R8, R9, R10, and R11, together with the atoms to which they are attached represent an optionally substituted cyclic group, the cyclic group so formed may be mono or polycyclic (preferably mono or bicyclic) and may be aromatic or nonaromatic. Examples of aromatic groups that may be so formed include benzene and naphthalene. Examples of non-aromatic groups that may be so formed include cyclopentane, cyclohexane, and cyclooctane. Any of R5, R6, R7, R8, R9, R10, and R11 together with the atoms to which they are attached may represent an optionally substituted cyclic group. Any of R5, R6, R7, R8, R9, R10, and R11 not representing a cyclic group are independently selected from hydrogen, an alkyl group and an alkenyl group as described herein. Two, three, four, five, or six of R5, R6, R7, R8, R9, R10, and R11 together with the atoms to which they are attached may represent an optionally substituted cyclic group. Suitably at least R5 and R7, or R5 and R9, or R5 and R11, or R7 and R9, or R7 and R11, or R5, R7 and R9, or R5, R7 and R11 together with the atoms to which they are attached may represent an optionally substituted cyclic group. For the avoidance of doubt, when any of R5, R6, R7, R8, R9, and R10 together with the atoms to which they are attached represent an optionally substituted cyclic group, one or more of R5, R6, R7, R8, R9, and R10 may contribute to one or more double bonds (for example, aromaticity) in the cyclic group. For example, R8 and R10 may together form a carbon-carbon double bond, which may form part of an aromatic cyclic group. The optionally substituted cyclic group represented by R1 and R2, or R3 and R4, or any of R5, R6, R7, R8, R9, R10, and R11, together with the atoms to which they are attached (when present) may be optionally substituted with any suitable substituent(s), such as for example one or more substituents independently selected from alkyl (for example C1-30, preferably C1-24, such as C1-4 or Ca-24, alkyl), alkenyl (for example C2-30, preferably C2-24, such as C2-4 or Ca-24, alkenyl), alkoxy (for example C1-30, preferably C1-24, such as C1-4 or Ca-24, alkoxy), alkenyloxy (for example C2-30, preferably C2-24, such as C2-4 or Ca-24, alkenyloxy), carboxy, alkoxy-carbonyl (for example C1-30, preferably C1-24, such as C1-4 or Ca-24, alkoxy-carbonyl), alkenyloxy-carbonyl (for example C2-30, preferably C2-24, such as C2-4 or Ca-24, alkenyloxy-carbonyl), hydroxy, halo (for example chloro or fluoro), nitro and cyano groups. The optionally substituted cyclic group represented by R1 and R2, or R3 and R4, or any of R5, R6, R7, R8, R9, R10, and R11, together with the atoms to which they are attached (when present) may alternatively be substituted by groups which form a further cyclic anhydride group. An example of such a cyclic anhydride is pyromellitic dianhydride. However, in some embodiments the cyclic anhydride monomers of the formula (I), (II) or (III) contain a single (i.e. only one) anhydride group. In such embodiments, the optionally substituted cyclic group represented by R1 and R2, or R3 and R4, or any of R5, R6, R7, R8, R9, R10, and R11, together with the atoms to which they are attached (when present) may not be substituted by a further cyclic anhydride group. Examples of suitable cyclic anhydrides of formula (I) in which R1 and R2 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group include optionally substituted 1,2-cyclohexanedicarboxylic anhydride and 1,3-cyclopentanedicarboxylic anhydride. 1,2-Cyclohexanedicarboxylic anhydride is preferred. Examples of suitable anhydrides of formula (II) in which R3 and R4 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group include optionally substituted phthalic anhydride, pyromellitic dianhydride, 1,2-naphthalic anhydride and 2,3-naphthalic anhydride. Examples of a substituted phthalic anhydride may include 1,2,4-benzenetricarboxylic anhydride, and 6-((octadec-9-en-1-yloxy)carbonyl)-1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid. Examples of suitable anhydrides of formula (III) in which any of R5, R6, R7, R8, R9, R10, and R11 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group include optionally substituted 1,8-naphthalic anhydride and homophthalic anhydride. Preferred cyclic anhydrides include one or more cyclic anhydrides of formula (I) wherein R1 and R2 are each independently selected from hydrogen and a Cs-3o, such as a Cs-24, alkyl or alkenyl group, or wherein R1 and R2 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group; or of formula (II) wherein R3 and R4 are each independently selected from hydrogen and a Cs-3o, such as a Cs-24, alkyl or alkenyl group, or wherein R3 and R4 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group; or of formula (III) wherein X is CR9R10, O, or S and R5, R6, R7, R8, R9, and R10 are each independently selected from hydrogen and a Cs-3o, such as a Cs-24, an alkyl group or alkenyl group, and / or wherein any of R5, R6, R7, R8, R9, and R10 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group. More preferred cyclic anhydrides include one or more cyclic anhydrides of formula (I) wherein R1 and R2 are each independently selected from hydrogen and a Cs-3o, such as a Cs-24, alkenyl group, or wherein R1 and R2 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group; or of formula (II) wherein R3 and R4 are both hydrogen, or wherein R3 and R4 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group; or of formula (III) wherein X is CR9R10, O, or S and R5, R6, R7, R8, R9, and R10 are each hydrogen, and / or wherein any of R5, R6, R7, R8, R9, and R10 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group. Preferably, at least one of the first reactants is a cyclic anhydride of formula (I), (II) or (III) wherein at least one of R1 and R2, or at least one of R3 and R4, or at least one of R5, R6, R7, R8, R9, R10, and R11, is a Cs-3o, such as a Cs-24, alkyl or alkenyl (more preferably alkenyl) group (such as an alkenyl group derived from a terminal olefin or an internal olefin, preferably an internal olefin). Preferably, at least one of the first reactants is a cyclic anhydride of formula (I), (II) or (III) wherein at least one of R1 and R2, or at least one of R3 and R4, or at least one of R5, R6, R7, R8, R9, R10, and R11, is a Ce-30, such as a Cs-24, alkyl or alkenyl (more preferably alkenyl) group (such as an alkenyl group derived from a terminal olefin or an internal olefin, preferably an internal olefin) and the other (or others) is (or are) hydrogen. For example, the cyclic anhydride may be an anhydride of formula (I) wherein R1 and R2 are both hydrogen (i.e. the cyclic anhydride may be succinic anhydride). For example, the cyclic anhydride may be an anhydride of formula (II) wherein R3 and R4 are both hydrogen (i.e. the cyclic anhydride may be maleic anhydride). For example, the cyclic anhydride may be an anhydride of formula (III) in which X is CR9R10 and R5, R6, R7, R8, R9, and R10 each represent hydrogen (i.e. the cyclic anhydride may be glutaric anhydride). For example, the cyclic anhydride may be an anhydride of formula (III) in which X is O and R5, R6, R7, and R8 each represent hydrogen (i.e. the cyclic anhydride may be diglycolic anhydride). For example, the cyclic anhydride may be an anhydride of formula (III) in which X is S and R5, R6, R7, and R8 each represent hydrogen (i.e. the cyclic anhydride may be thiodiglycolic anhydride). For example, the or each cyclic anhydride may be an anhydride of formula (I) wherein R1 and R2 are both hydrogen or wherein one of R1 and R2 is an alkyl or alkenyl group (such as an alkenyl group derived from a terminal olefin or an internal olefin, preferably an internal olefin) and the other of R1 and R2 is hydrogen. For example, the or each cyclic anhydride may be an anhydride of formula (I) wherein R1 and R2 are both hydrogen or wherein one of R1 and R2 is a Ce-3o, such as a Cs-24, alkyl or alkenyl (more preferably alkenyl) group (such as an alkenyl group derived from a terminal olefin or an internal olefin, preferably an internal olefin) and the other of R1 and R2 is hydrogen. Examples of such cyclic anhydride compounds include succinic anhydride, C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, C15-18 internal olefin-derived alkenyl succinic anhydride, C16 internal olefin-derived alkenyl succinic anhydride, and C16 terminal olefin-derived alkenyl succinic anhydride. The cyclic anhydride compound may be selected from succinic anhydride, C2o-24alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride and octenyl succinic anhydride. The cyclic anhydride compound is preferably selected from C15-18 internal olefin-derived alkenyl succinic anhydride, C16 internal olefin-derived alkenyl succinic anhydride, and C16 terminal olefin-derived alkenyl succinic anhydride. Preferably, the or each cyclic anhydride may be an anhydride of formula (I) wherein one of R1 and R2 is an alkenyl group, such as a C6-30 (preferably C8-24) alkenyl group (such as a C6-30 (preferably C8-24) alkenyl group derived from a terminal olefin or an internal olefin, preferably an internal olefin), and the other of R1 and R2 is hydrogen. Examples of such cyclic anhydride compounds include C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, C15-18 internal olefin-derived alkenyl succinic anhydride, C16 internal olefin-derived alkenyl succinic anhydride, and C16 terminal olefin-derived alkenyl succinic anhydride. The cyclic anhydride compound may be selected from C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride and octenyl succinic anhydride. The cyclic anhydride compound is preferably selected from C15-18 internal olefin-derived alkenyl succinic anhydride, C16 internal olefin-derived alkenyl succinic anhydride, and C16 terminal olefin-derived alkenyl succinic anhydride. Preferably, the or each cyclic anhydride may be dodecenyl succinic anhydride, such as (2-dodecen-1-yl)succinic anhydride. The or each cyclic anhydride may be an anhydride of formula (I) wherein one of R1 and R2 is hydrogen and the other of R1 and R2 is a polyisobutenyl group, for example wherein the polyisobutenyl group suitably has a number average molecular weight of from 100 to 2000, preferably from 100 to 1000, for example 260 or 550. Preferably, the or each cyclic anhydride may be a cyclic anhydride of formula (I) or (II) wherein R1 and R2, or R3 and R4, together with the carbon atoms to which they are attached represent an optionally substituted cyclic group, wherein the cyclic group is an aromatic or a non-aromatic group and is mono or polycyclic. Preferably, the or each cyclic anhydride may be an anhydride of formula (I) wherein R1 and R2 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group, wherein the cyclic group is a non-aromatic (for example saturated) mono or bicyclic group. More preferably, the or each cyclic anhydride may be a cyclic anhydride of formula (I) wherein R1 and R2 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group, wherein the cyclic group is a non-aromatic (for example saturated) monocyclic group, such as a cyclohexane group. Preferably, the or each cyclic anhydride may be an anhydride of formula (II) wherein R3 and R4 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group, wherein the cyclic group is an aromatic mono or bicyclic group, such as a benzene or naphthalene group. More preferably, the or each cyclic anhydride may be a cyclic anhydride of formula (II) wherein R3 and R4 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group, wherein the cyclic group is an aromatic monocyclic group, such as a benzene group. Preferably, the or each cyclic anhydride may be an anhydride of formula (III) wherein X is CR9R10 and R5, R6, R7, R8, R9, and R10 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group, wherein the cyclic group is an aromatic bicyclic group, such as a naphthalene group; or R7 and R8 are hydrogen and R5, R6, R9 and R10 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group, wherein the cyclic group is an aromatic monocyclic group, such as a benzene group. More preferably, the or each cyclic anhydride may be an anhydride of formula (III) wherein X is CR9R10 and R5, R6, R7, R8, R9, and R10 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group, wherein the cyclic group is an aromatic bicyclic group, such as a naphthalene group. When the cyclic anhydride is an anhydride of formula (I) wherein R1 and R2 together with the carbon atoms to which they are attached represent an optionally substituted cyclohexane group, the cyclic anhydride may be of the formula (IA): wherein n is an integer from 0 to 4 and each R12 (when present) is independently selected from alkyl (for example C1-30, preferably C1-24, such as C1-4, alkyl), alkenyl (for example C2-30, preferably C2-24, such as C2-4, alkenyl), alkoxy (for example C1-30, preferably C1-24, such as C1-4, alkoxy), alkenyloxy (for example C2-30, preferably C2-24, such as C2-4, alkenyloxy), carboxy, alkoxy-carbonyl (for example C1-30, preferably C1-24, such as C1-4, alkoxy-carbonyl), alkenyloxycarbonyl (for example C2-30, preferably C2-24, such as C2-4, alkenyloxy-carbonyl), hydroxy, halo (for example chloro or fluoro), nitro and cyano groups, or when n is 2 the two R12 groups may represent a further cyclic anhydride group (such as a further succinic anhydride group). In some embodiments, the cyclic anhydride of formula (IA) contains a single (i.e. only one) anhydride group. In such embodiments, two R12 groups may not represent a further cyclic anhydride group. Examples of suitable succinic anhydrides of formula (IA) include 1,2-cyclohexanedicarboxylic anhydride. When the cyclic anhydride is an anhydride of formula (II) wherein R3 and R4 together with the carbon atoms to which they are attached represent an optionally substituted benzene group, the cyclic anhydride may be of the formula (HA): wherein n’ is an integer from 0 to 4 and each R13 (when present) is independently selected from alkyl (for example C1-30, preferably C1-24, such as C1-4, alkyl), alkenyl (for example C2-30, preferably C2-24, such as C2-4, alkenyl), alkoxy (for example C1-30, preferably C1-24, such as C1-4, alkoxy), alkenyloxy (for example C2-30, preferably C2-24, such as C2-4, alkenyloxy), carboxy, alkoxy-carbonyl (for example C1-30, preferably C1-24, such as C1-4, alkoxy-carbonyl), alkenyloxycarbonyl (for example C2-30, preferably C2-24, such as C2-4, alkenyloxy-carbonyl), hydroxy, halo (for example chloro or fluoro), nitro and cyano groups, or when n’ is 2 the two R13 groups may represent a further cyclic anhydride group (such as a further succinic anhydride group). When R13 represents a alkoxy-carbonyl (for example C1-30, preferably Ca-24, alkoxy-carbonyl) or alkenyloxy-carbonyl (for example C2-30, preferably Ca-24, alkenyloxy-carbonyl), substituent, the alkoxy-carbonyl or alkenyloxy-carbonyl group may be of the formula -C(O)OR13 wherein R13 is a C1-30, preferably Ca-24, alkyl group or a C2-30, preferably Ca-24, alkenyl group. Suitably R13 may represent an oleyl group. Examples of suitable succinic anhydrides of formula (HA) include phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-naphthalic anhydride and 2,3-naphthalic anhydride, and 6-((octadec-9-en-1-yloxy)carbonyl)-1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid. When the cyclic anhydride is an anhydride of formula (III) wherein X is CR9R10 and R5, R6, R7, R8, R9, and R10 together with the carbon atoms to which they are attached represent an optionally substituted naphthalene group, the cyclic anhydride may be of the formula (IIIA): (R (IHA) wherein each of m and m’ is independently an integer from 0 to 3 and each of R14 and R15 (when present) is independently selected from alkyl (for example C1-30, preferably C1-24, such as C1-4, alkyl), alkenyl (for example C2-30, preferably C2-24, such as C2-4, alkenyl), alkoxy (for example Ci-30, preferably C1-24, such as C1-4, alkoxy), alkenyloxy (for example C2-30, preferably C2-24, such as C2-4, alkenyloxy), carboxy, alkoxy-carbonyl (for example C1-30, preferably C1-24, such as C1-4, alkoxy-carbonyl), alkenyloxy-carbonyl (for example C2-30, preferably C2-24, such as C2-4, alkenyloxy-carbonyl), hydroxy, halo (for example chloro or fluoro), nitro and cyano groups. Examples of suitable succinic anhydrides of formula (IIIA) include 1,8-naphthalic anhydride. When the cyclic anhydride is an anhydride of formula (III) wherein X is CR9R10, R7 and R8 are hydrogen and R5, R6, R9 and R10 together with the carbon atoms to which they are attached represent an optionally substituted benzene group, the cyclic anhydride may be of the formula (IIIB): wherein m” is an integer from 0 to 4 and each R16 (when present) is independently selected from alkyl (for example C1-30, preferably C1-24, such as C1-4, alkyl), alkenyl (for example C2-30, preferably C2-24, such as C2-4, alkenyl), alkoxy (for example C1-30, preferably C1-24, such as C1-4, alkoxy), alkenyloxy (for example C2-30, preferably C2-24, such as C2-4, alkenyloxy), carboxy, alkoxy-carbonyl (for example C1-30, preferably C1-24, such as C1-4, alkoxy-carbonyl), alkenyloxycarbonyl (for example C2-30, preferably C2-24, such as C2-4, alkenyloxy-carbonyl), hydroxy, halo (for example chloro or fluoro), nitro and cyano groups. Examples of suitable succinic anhydrides of formula (IIIB) include homophthalic anhydride. Suitably, the or each cyclic anhydride may be selected from one or more of succinic anhydride, maleic anhydride, glutaric anhydride, a C6-30 alkenyl succinic anhydride such as C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, octadecyl succinic anhydride, octyl succinic anhydride, C15-18 internal olefin-derived alkenyl succinic anhydride, C16 internal olefin-derived alkenyl succinic anhydride, or C16 terminal olefinderived alkenyl succinic anhydride, a branched alkenyl succinic anhydride such as tetrapropenyl succinic anhydride or polyisobutenyl succinic anhydride, phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 1,2-naphthalic anhydride, 2,3-naphthalic anhydride, 1,8-naphthalic anhydride and homophthalic anhydride. Suitably, the or each cyclic anhydride may be selected from one or more of succinic anhydride, maleic anhydride, glutaric anhydride, a C6-30 alkenyl succinic anhydride such as C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, octadecyl succinic anhydride, or octyl succinic anhydride, a branched alkenyl succinic anhydride such as tetrapropenyl succinic anhydride or polyisobutenyl succinic anhydride, phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 1,2-naphthalic anhydride, 2,3-naphthalic anhydride, 1,8-naphthalic anhydride and homophthalic anhydride. Suitably, the or each cyclic anhydride may be selected from one or more of a C6-30 alkenyl succinic anhydride such as C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, octadecyl succinic anhydride, or octyl succinic anhydride, a branched alkenyl succinic anhydride such as tetrapropenyl succinic anhydride or polyisobutenyl succinic anhydride, phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 1,2-naphthalic anhydride, 2,3-naphthalic anhydride, 1,8-naphthalic anhydride and homophthalic anhydride. Suitably, the or each cyclic anhydride may be selected from one or more of succinic anhydride, maleic anhydride, glutaric anhydride, a C6-30 alkenyl succinic anhydride such as C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, octadecyl succinic anhydride, or octyl succinic anhydride, and a branched alkenyl succinic anhydride such as tetrapropenyl succinic anhydride or polyisobutenyl succinic anhydride. Suitably, the or each cyclic anhydride may be selected from one or more of phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 1,2-naphthalic anhydride, 2,3-naphthalic anhydride, 1,8-naphthalic anhydride and homophthalic anhydride. More suitably, the or each cyclic anhydride may be selected from one or more of succinic anhydride, maleic anhydride, C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 1,2-naphthalic anhydride, 2,3-naphthalic anhydride, 1,8-naphthalic anhydride, homophthalic anhydride and glutaric anhydride. More suitably, the or each cyclic anhydride may be selected from one or more of succinic anhydride, maleic anhydride, C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, and glutaric anhydride. More suitably, the or each cyclic anhydride may be selected from one or more of C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, and glutaric anhydride. Preferably, the or each cyclic anhydride may be selected from one or more of succinic anhydride, maleic anhydride, C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-cyclohexanedicarboxylic anhydride and 1,8-naphthalic anhydride. Preferably, the or each cyclic anhydride may be selected from one or more of succinic anhydride, maleic anhydride, C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, and octenyl succinic anhydride. Preferably, the or each cyclic anhydride may be selected from one or more of C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, and octenyl succinic anhydride. Preferably, the or each cyclic anhydride may be selected from one or more of phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-cyclohexanedicarboxylic anhydride and 1,8-naphthalic anhydride. Preferably, the or each cyclic anhydride may be selected from one or more of C15-18 internal olefin-derived alkenyl succinic anhydride, C16 internal olefin-derived alkenyl succinic anhydride, and C16 terminal olefin-derived alkenyl succinic anhydride. The cyclic anhydride compounds discussed herein may be commercially available or may be prepared using procedures well known in the art. For example, alkenyl substituted succinic anhydrides are typically prepared by the reaction of an alkene with maleic anhydride. Preferably, the or each cyclic anhydride may be independently selected from a C6-30 alkyl or alkenyl substituted succinic anhydride, phthalic anhydride and pyromellitic dianhydride. Preferably, the or each cyclic anhydride may be independently selected from a C6-30 alkyl or alkenyl substituted succinic anhydride. Preferably, the or each cyclic anhydride may be independently selected from a C6-30 alkenyl substituted succinic anhydride wherein the alkenyl group is derived from a terminal olefin or an internal olefin, preferably an internal olefin. Preferably, the or each cyclic anhydride may be independently selected from (2-dodecen-1-yl)succinic anhydride, nonenyl succinic anhydride, octadecenyl succinic anhydride, C15-18 internal olefin-derived alkenyl succinic anhydride, C16 internal olefin-derived alkenyl succinic anhydride, C16 terminal olefin-derived alkenyl succinic anhydride, tetrapropenyl succinic anhydride, phthalic anhydride and pyromellitic dianhydride. Preferably, the or each cyclic anhydride may be independently selected from (2-dodecen-1-yl)succinic anhydride, nonenyl succinic anhydride, octadecenyl succinic anhydride, phthalic anhydride and pyromellitic dianhydride. Preferably, the or each cyclic anhydride may be independently selected from (2-dodecen-1-yl)succinic anhydride, nonenyl succinic anhydride, and octadecenyl succinic anhydride. Preferably, the or each cyclic anhydride may be independently selected from phthalic anhydride and pyromellitic dianhydride. The cyclic anhydride compounds discussed herein may be commercially available or may be prepared using procedures well known in the art. The or each of the one or more second reactants used to make the ester compound is a polyol. Mixtures of two or more different second reactants (i.e. different polyols) may be used to make the ester compound. Any suitable polyol may be used to make the ester compound, as would be understood by the person skilled in the art. The term polyol is used to refer to any compound including two or more hydroxy (OH) functional groups. In some embodiments the or each polyol may comprise carbon, hydrogen and oxygen atoms, and optionally additionally nitrogen atoms. In other embodiments, the or each polyol may consist essentially of or consist of carbon, hydrogen and oxygen atoms. Suitable polyols for preparing the ester compound may be compounds having from 2 to 10, preferably from 2 to 6, more preferably 2 or 3, hydroxy groups. In some embodiments the polyol may have only two hydroxy groups (i.e. the polyol may be a diol). Suitable polyols may include one or more of a polyol of formula (IV): H-(OR17)P-OH (IV) wherein each R17 is independently an optionally substituted hydrocarbylene group and p is an integer of at least 1. When p is an integer of greater than 1, the polyol of formula (IV) may comprise groups R17 that are all the same or may comprise groups R17that are different. Suitably, each R17 in the formula (IV) may be the same. Preferably p is an integer from 1 to 140, such as from 1 to 110, from 1 to 40 or from 1 to 10. For example, suitable polyols may include one or more of a polyol of formula (IVA): H-(OR18)q-OH (IVA) wherein each R18 is independently an optionally substituted alkylene group and q is an integer of at least 1. When q is an integer of greater than 1, the polyol of formula (IV) may comprise groups R18 that are all the same or may comprise groups R18 that are different. Suitably, each R18 in the formula (IVA) is the same. Preferably q is an integer from 1 to 140, such as from 1 to 110, from 1 to 40 or from 1 to 10. When the polyol of formula (IV) or (IVA) contains a substituted hydrocarbylene or alkylene group, any suitable substituent may be present, such as for example a carboxy or amido substituent. The polyol of formula (IVA) may have more than 2 hydroxy groups and the group R18 may be a hydroxy substituted alkylene group. Each hydroxy substituted alkylene group R18 may have 1,2 or more hydroxy groups. Each hydroxy substituted alkylene group R18 may preferably have 1 hydroxy group. The polyol of formula (IVA) may have 2 hydroxy groups and the group R18 may be an optionally substituted alkylene group wherein the optional substituent is not hydroxy. The polyol of formula (IV) or of formula (IVA) may be a sugar derived compound in which R17 or R18 includes one or more hydroxy residues. The or each R17 or R18 may represent a cyclic alkylene unit. One or more heteroatoms (for example oxygen atoms) may be present in the cyclic alkylene unit. For example the unit may contain an ether linkage. Suitably the or each R17 or R18 may be one or more saccharide units or may be substituted with one or more saccharide units. Suitably the or each R17 or R18 may be an unsubstituted alkylene group. Preferably the or each R17 or R18 is an optionally substituted alkylene group having from 1 to 50, such as from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, suitably from 1 to 12 or from 1 to 10, for example from 2 to 6, carbon atoms. Preferably the or each R17 or R18 is an unsubstituted alkylene group having from 1 to 50, preferably from 1 to 20, more preferably from 1 to 12 or from 1 to 10, suitably from 2 to 6 carbon atoms. Each R17 or R18 may be straight chained or branched. Suitably the or each R17 or R18 may be an ethylene, propylene, butylene, pentylene, hexylene or dodecylene group. When R17 or R18 has more than 2 carbon atoms any isomer may be present. Preferably R17 or R18 is an ethylene or a propylene group, most preferably an ethylene group. When q is 1, R18 may be a group of formula (CH2)x wherein x is from 2 to 12, preferably from 3 to 12. Suitably when q is 1, R18 may be a straight chain or branched optionally substituted alkylene group and the polyol may be selected from ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,6-hexanediol, 1,12-dodecanediol, trimethylolpropane, 2-ethyl-1,3,-hexanediol, 2,2-diethyl-1,3-propanediol, 2,2-bis(hydroxymethyl)propionic acid, pentaerythritol, sorbitol, xylitol, glycerol and neopentyl glycol. Suitably when q is 1, R18 may be a straight chain or branched alkylene group having from 2 to 12, preferably from 3 to 12, carbon atoms. Suitable compounds of this type include ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,6-hexanediol, 1,12-dodecanediol, trimethylolpropane, 2-ethyl-1,3,-hexanediol, 2,2-diethyl-1,3-propanediol, pentaerythritol and neopentyl glycol. Suitably when q is 1, R18 may be a branched alkylene group having from 2 to 12, preferably from 3 to 12, carbon atoms. Suitable compounds of this type include propylene glycol, 1,2-butanediol, 1,3-butanediol, trimethylolpropane, 2-ethyl-1,3,-hexanediol, 2,2-diethyl-1,3-propanediol, pentaerythritol and neopentyl glycol. Suitably when q is 2 or more, the or each R18 may be a straight chain or branched alkylene group and the polyol may, for example, be selected from diglycerol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol and polypropylene glycol. Suitably when q is 2 or more, the or each R18 may be a straight chain or branched alkylene group having from 2 to 4, preferably 2 or 3, carbon atoms. Suitable compounds of this type include diethylene glycol, triethylene glycol, di propylene glycol, tripropylene glycol, polyethylene glycol (PEG), for example having a number average molecular weight of from 150 to 6000, and polypropylene glycol (PPG), for example having a number average molecular weight of from 400 to 2000. Suitable polyols may include one or more of PEG 6000, PEG 1500, PEG 1000, PEG 600, PEG 400, PEG 200, PPG 2000, PPG 1000 and PPG 425. The or each R17 or R18 may comprise a mixture of isomers. For example when R17 or R18 is propylene, the polyol may include moieties -CH2CH(CH3)- and -CH(CH3)CH2- in any order within the chain. R17 or R18 may comprise a mixture of different groups for example ethylene, propylene or butylene units. The or each R18 may be an ethylene, propylene or butylene group. For example, the or each R18 may be an n-propylene or n-butylene group or an isopropylene or isobutylene group. For example the or each R18 may be -CH2CH2-, -CH2CH(CH3)-, - CH(CH3)CH2-, CH2CH2CH2-, -CH2C(CH3)2-, -CH2CH2CH2CH2-, -CH(CH3)CH(CH3)- or -CH2CH(CH2CH3)-. Preferably R18 is selected from -CH2CH2-, -CH2CH2CH2-, -CH(CH3)CH2- or -CH2CH(OH)CH2, more preferably from -CH2CH2-, and-CH2CH2CH2-. Suitably the polyol of formula (IV) or (IVA) may be a sugar derived alcohol, for example, glucose, fructose, trehalose, sucrose, lactose, maltose or sorbitol, preferably sorbitol. Suitably the polyol of formula (IV) may be selected from one or more of 1,12-dodecanediol, 1,6-hexanediol, trimethylolpropane, neopentyl glycol, polyethylene glycol (such as PEG 6000, PEG 1500, PEG 1000, PEG 600, PEG 400, PEG 200), polypropylene glycol (such as PPG 2000, PPG 1000, PPG 425), sorbitol, trimethylolpropane and xylitol. Suitably, the polyol, for example of formula (IV), may be an ester of glycerol (also known as a glyceride) and a hydroxycarboxylic acid. The ester of glycerol may be a mono-, di- or triglyceride, suitably a tri-glyceride. Suitably, the hydroxycarboxylic acid comprises one or more hydroxyl groups and one or more carboxylic acid groups. The hydroxycarboxylic acid may be a monocarboxylic acid comprising one or more hydroxyl groups. The hydroxycarboxylic acid may be of the formula R19COOH, wherein R19 is a hydroxylsubstituted hydrocarbyl group. R19is suitably a hydroxy-substituted alkyl, alkenyl or alkaryl group, preferably a hydroxy-substituted alkyl or alkenyl group. R19 suitably comprises from 1 to 25 carbon atoms, preferably from 1 to 20 carbon atoms, more preferably from 1 to 17 carbon atoms. Suitably, the hydroxycarboxylic acid may be selected from glycolic acid, lactic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxystearic acid (preferably 12-hydroxystearic acid), 2,2-bis(hydroxymethyl)propionic acid, mandelic acid or ricinoleic acid. Preferably, the hydroxycarboxylic acid or the cyclic ester thereof may be selected from glycolic acid, mandelic acid, ricinoleic acid, malic acid, tartaric acid or citric acid. More preferably, the hydroxycarboxylic acid or the cyclic ester thereof is ricinoleic acid. Preferably, when the polyol is an ester of glycerol, the polyol may be a mono-, di- or tri-glyceride of ricinoleic acid. Most preferably, when the polyol is an ester of glycerol, the polyol may be a tri-glyceride of ricinoleic acid, such as castor oil. Suitable polyols may include one or more of an alkoxylated polyol of formula (IV) or (IVA). These polyols may be the reaction product of a polyol of formula (IV) or (IVA) and one or more alkylene oxides, such as ethylene oxide or propylene oxide. Such alkoxylated polyols may include polyoxyethylene (80) sorbitan monooleate (also known as Tween® 80) and 2,4,7,9-tetramethyl-5-decyne-4,7-diol ethoxylate. Preferably, the or each polyol may be independently selected from castor oil, 1,6-hexanediol, sorbitol, neopentyl glycol and a polyalkylene glycol (such as PEG 200). When the or each polyol comprises carbon, hydrogen, oxygen and nitrogen atoms, the or each polyol may comprise two or more (such as 2 or 3) hydroxy groups and one or more (suitably one) amine groups. The amine groups may suitably be secondary or tertiary amines. Preferably the amine groups are tertiary amines. These polyols may be referred to herein as nitrogen containing polyols. For example, suitable nitrogen containing polyols may include one or more of a polyol of formula (V) or a derivative thereof: NR20R21R22 (V) wherein R20, R21 and R22 are each independently selected from hydrogen, hydroxyalkyl and hydrocarbyl, provided that at least two of R20, R21 and R22 represents a hydroxyalkyl group. Preferably, the at least two of R20, R21 and R22 that represent a hydroxyalkyl group are the same. For example, in the compounds of formula (V), R20 and R21 may each represent hydroxyalkyl and R22 may represent hydrogen, hydroxyalkyl or hydrocarbyl. In the formula (V), the hydroxyalkyl group may contain from 1 to 8, such as from 1 to 4, such as 2 or 3, carbon atoms. For example, each hydroxyalkyl group may be hydroxyethyl or hydroxypropyl, particularly hydroxyethyl. In the formula (V), the hydrocarbyl group (when present) may represent any suitable such group, such as an alkyl group, for example an alkyl group containing from 1 to 10, such as from 1 to 6 or from 1 to 4, carbon atoms. Thus, the hydrocarbyl group may represent a methyl, ethyl, propyl or butyl group (especially butyl or methyl). For example, in the compounds of formula (V), R20 and R21 may each represent hydroxyalkyl and R22 may represent hydrogen, hydroxyalkyl or hydrocarbyl (especially hydrogen or hydrocarbyl, more especially hydrocarbyl). In some embodiments, the R20 and R21 may each represent hydroxyalkyl and R22 may represent hydroxyalkyl or hydrocarbyl. Preferably in the compounds of formula (V), R20 and R21 both represent hydroxyethyl and R22 represents hydrogen or hydrocarbyl, such as a hydrocarbyl group containing from 1 to 6, or from 1 to 4, carbon atoms. Preferably in the compounds of formula (V), R20 and R21 both represent hydroxyethyl and R22 represents hydrogen or an alkyl group containing from 1 to 6, or from 1 to 4, carbon atoms (especially methyl). Examples of suitable nitrogen containing polyols include N-methyl diethanolamine, N-butyl diethanolamine, triethanolamine and diethanolamine, and derivatives thereof. The or each nitrogen containing polyol may be independently selected from N-methyl diethanolamine, N-butyl diethanolamine, and triethanolamine, and derivatives thereof. The or each nitrogen containing polyol may be independently selected from N-methyl diethanolamine, N-butyl diethanolamine, and triethanolamine. References herein to nitrogen containing polyols include derivatives thereof, such as a corresponding quaternary compound. Thus, as example of a suitable derivative of a nitrogen containing polyol is tris(2-hydroxyalkyl)methylammonium compound, for example tris(2-hydroxyethyl)methylammonium methylsulfate, which is a quaternary ammonium salt of triethanolamine. In some preferred embodiments, the nitrogen containing polyols are not derivatised, for example they are not quaternary ammonium salts. Preferably, the or each nitrogen containing polyol may be independently selected from N-butyl diethanolamine, diethanolamine and N-methyl diethanolamine, and derivatives (for example quaternary ammonium salts) thereof. Preferably, the or each nitrogen containing polyol may be independently selected from N-butyl diethanolamine and N-methyl diethanolamine, and derivatives (for example quaternary ammonium salts) thereof. Further examples of suitable nitrogen containing polyols include those formed by reaction of a hydroxy substituted cyclic ester or cyclic carbonate, such as glycerol carbonate or gluconolactone, with a suitable primary or secondary amine compound, such as ethanolamine, dipropylamine, hexylamine, dodecylamine, phenethylamine, dipropylamine, ethylenediamine, or a polyether polyamine. Suitable polyether amines may include polyether monoamines (such as for example Jeffamine M-1000) and polyether polyamines (such as for example Jeffamine ED- 600). As the skilled person would appreciate, the reaction of a hydroxy substituted cyclic ester or cyclic carbonate with a suitable primary or secondary amine compound will result in a ring opening reaction to form a compound such as a N-carbamoyl polyol or an amido polyol. The or each polyol may be selected from one or more polyol of the formula (IV) or (IVA) as defined herein (including an ester of glycerol and a hydroxycarboxylic acid (such as castor oil)), one or more of an alkoxylated polyol of formula (IV) or (IVA) as defined herein, one or more nitrogen containing polyol as defined herein (including compounds of the formula (V)) and one or more polyol formed by reaction of a hydroxy substituted cyclic ester or cyclic carbonate with a suitable primary or secondary amine compound. Preferably, the or each polyol may be selected from one or more polyol of the formula (IV) or (IVA) as defined herein (including an ester of glycerol and a hydroxycarboxylic acid (such as castor oil)), one or more of an alkoxylated polyol of formula (IV) or (IVA) as defined herein, one or more nitrogen containing polyol of the formula (V) as defined herein and one or more polyol formed by reaction of a hydroxy substituted cyclic ester or cyclic carbonate with a suitable primary or secondary amine compound. More preferably, the or each polyol may be selected from one or more polyol of the formula (IV) or (IVA) as defined herein (such as an ester of glycerol and a hydroxycarboxylic acid , for example castor oil), and one or more nitrogen containing polyol of the formula (V) as defined herein. In one embodiment, the or each polyol may be selected from one or more polyol of the formula (IV) or (IVA) as defined herein, such as an ester of glycerol and a hydroxycarboxylic acid (for example castor oil). In another embodiment, the or each polyol may be selected from one or more of an alkoxylated polyol of formula (IV) or (IVA) as defined herein. In one embodiment, the or each polyol may be selected from one or more polyol of the formula (IV) or (IVA) as defined herein, such as an ester of glycerol and a hydroxycarboxylic acid (for example castor oil) and from one or more of an alkoxylated polyol of formula (IV) or (IVA) as defined herein. In another embodiment, the or each polyol may be selected from one or more nitrogen containing polyol as defined herein (including compounds of the formula (V)). In another embodiment, the or each polyol may be selected from one or more polyol formed by reaction of a hydroxy substituted cyclic ester or cyclic carbonate with a suitable primary or secondary amine compound. In one embodiment, the ester compound may be the reaction product of reactants comprising one (i.e. a single) cyclic anhydride and one (i.e. a single) polyol. In other embodiments, the ester compound may be the reaction product of reactants comprising two different cyclic anhydrides and one (i.e. a single) polyol , or the ester compound may be the reaction product of reactants comprising one (i.e. a single) cyclic anhydride and two different polyols. The combined amount of the one or more first reactants and the one or more second reactants may be at least 50 mol%, suitably at least 75 mol%, preferably at least 90 mol%, for example at least 95 wt% of the reactants that are reacted to obtain the ester compound. In one embodiment, the ester compound may be the reaction product of reactants consisting essentially of or consisting of one (i.e. a single) cyclic anhydride and one (i.e. a single) polyol. In other embodiments, the ester compound may be the reaction product of reactants consisting essentially of or consisting of two different cyclic anhydrides and one (i.e. a single) polyol , or the ester compound may be the reaction product of reactants consisting essentially of or consisting of one (i.e. a single) cyclic anhydride and two different polyols. The ester compound for use herein may be the reaction product of reactants comprising the one or more first reactants and one or more second reactants as disclosed herein and additionally one or more third reactants. In other words, the ester compound may be the reaction product of reactants comprising one or more first reactants as disclosed herein, one or more second reactants as disclosed herein and one or more third reactants. The one or more third reactants may for example act as end capping groups and / or may introduce additional functional groups to the ester compounds. The one or more third reactants may be selected to impart the desired groups and / or properties to the ester compound by the person skilled in the art. The combined amount of the one or more first reactants, the one or more second reactants, and the one or more third reactants may be at least 50 mol%, suitably at least 75 mol%, preferably at least 90 mol%, for example at least 95 wt% of the reactants that are reacted to obtain the ester compound. The ester compound for use herein may be the reaction product of reactants consisting essentially of or consisting of the one or more first reactants and one or more second reactants as disclosed herein and additionally one or more third reactants. In other words, the ester compound may be the reaction product of reactants consisting essentially of or consisting one or more first reactants as disclosed herein, one or more second reactants as disclosed herein and one or more third reactants. The ester compound for use herein is suitably the reaction product of no more than four different reactants. Preferably, the ester compound is the reaction product of no more than three different reactants. For example, the ester compound may be the reaction product of one first reactant, one second reactant, and one third reactant, or the reaction product of two different first reactants and one second reactant as disclosed herein. In some preferred embodiments, the ester compound is the reaction product of only two different reactants, i.e. one first reactant and one second reactant as disclosed herein (and no further reactants). Examples of suitable third reactants include one or more of the following: (i) polycarboxylic acids or reactive equivalents thereof; (ii) monocarboxylic acids or esters thereof; (iii) hydroxycarboxylic acids or cyclic esters thereof; (iv) epoxide compounds; (v) polyfunctional reactants having a reactive amino group; (vi) monoalcohols; and (vii) monofunctional reactants having a reactive amino group. The third reactant may be (i) a polycarboxylic acid or a reactive equivalent thereof. Suitable polycarboxylic acids comprise two or more carboxylic acid groups, such as two or three carboxylic acid groups. Preferred polycarboxylic acids are dicarboxylic acids. The polycarboxylic acid may be aliphatic or aromatic. The aliphatic polycarboxylic acid may be cycloaliphatic. The aliphatic polycarboxylic acid may be saturated or unsaturated. By the term “unsaturated” we mean that the polycarboxylic acid comprises one or more carbon-carbon double bonds. The polycarboxylic acid may comprise one or more heteroatoms other than in the carboxylic acid groups. By the term “heteroatoms” we mean atoms other than carbon or hydrogen, such as oxygen, nitrogen and sulfur atoms. For example, the polycarboxylic acid may comprise one or more moieties selected from hydroxy groups, amino groups, ether groups, and / or thioether groups. Reactive equivalents of polycarboxylic acids may be used. By the term “reactive equivalent”, we mean a compound that results in the same reaction product as the corresponding polycarboxylic acid. Suitable reactive equivalents include acid chlorides and esters of the polycarboxylic acids described herein. Examples of suitable polycarboxylic acids or reactive equivalents thereof include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, maleic acid, fumaric acid, malic acid, tartaric acid, citric acid, C20-24 alkenyl succinic acid, dodecenyl succinic acid (such as (2-dodecen-1-yl)succinic acid), nonenyl succinic acid, octadecenyl succinic acid, octenyl succinic acid, polyisobutenylsuccinic acid, itaconic acid, 1,2-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, homophthalic acid, 1,2,4-benzenetricarboxylic acid, pyromellitic acid, 1,2-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diglycolic acid, thiodiglycolic acid, 3,3’-thiodipropanoic acid, iminodiacetic acid, poly(ethylene glycol)bis(carboxymethyl) ether, a dimer acid, and acid chlorides and esters thereof. Preferably, the polycarboxylic acid is selected from pimelic acid, suberic acid, sebacic acid, dodecanedioic acid, citric acid, diglycolic acid, thiodiglycolic acid, poly(ethylene glycol)bis(carboxymethyl) ether, or a hydrogenated dimer acid. The third reactant may be (ii) a monocarboxylic acid or an ester thereof. Suitable monocarboxylic acids may be aliphatic or aromatic. The aliphatic monocarboxylic acid may be cycloaliphatic. The aliphatic monocarboxylic acid may be saturated or unsaturated. The monocarboxylic acid may contain from 2 to 40 carbon atoms, suitably from 4 to 30 carbon atoms, preferably from 6 to 20 carbon atoms, for example from 8 to 18 carbon atoms. The monocarboxylic acid may be a fatty acid. Examples of suitable monocarboxylic acids or esters thereof include hexanoic acid, octanoic acid, decanoic acid, lauric acid, myristic acid, myristoleic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, elaidic acid, linoleic acid, linolelaidic acid, arachidic acid, arachidonic acid, behenic acid, erucic acid, and esters (preferably methyl esters) thereof. Preferably, the monocarboxylic acid is selected from propionic acid, hexanoic acid, lauric acid, stearic acid, oleic acid, or erucic acid. The third reactant may be (iii) a hydroxycarboxylic acid or a cyclic ester thereof. Suitable hydroxycarboxylic acids comprise one or more hydroxy groups and one or more carboxylic acid groups. The hydroxycarboxylic acid may be a monocarboxylic acid comprising one or more hydroxy groups. By the term “cyclic ester” of a hydroxycarboxylic acid we mean a compound comprising a cyclic group, wherein the cyclic group comprises one or more ester groups. The ester may be a cyclic monoester or a cyclic diester. The cyclic ester may correspond to a single cyclised molecule of the hydroxycarboxylic acid. This may, for example, be formed by an intramolecular reaction between the hydroxy group and the carboxylic acid group on one molecule of the hydroxycarboxylic acid. Alternatively, the cyclic ester may correspond to a cyclic dimer of a hydroxycarboxylic acid. This may, for example, be formed by an intermolecular reaction between the hydroxy groups and the carboxylic acid groups on two molecules of the hydroxycarboxylic acid. Examples of suitable hydroxycarboxylic acids or cyclic esters thereof include glycolic acid, lactic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxystearic acid (preferably 12-hydroxystearic acid), dihydroxystearic acid, 2,2-bis(hydroxymethyl)propionic acid, mandelic acid, ricinoleic acid, malic acid, tartaric acid, citric acid, y-butyrolactone, 6-valerolactone, s-caprolactone, menthide, D-lactide, L-lactide, or DL-lactide. Preferably, the hydroxycarboxylic acid is selected from ricinoleic acid or citric acid. The third reactant may be (iv) an epoxide compound. Suitable epoxide compounds may comprise one or more than one epoxide group. For example, suitable epoxide compounds may comprise two epoxide groups. Examples of suitable epoxide compounds include 1,2-epoxydodecane, ethyl glycidyl ether, isopropyIglycidyI ether, 2-ethylhexyl glycidyl ether, octyl glycidyl ether, nonyl glycidyl ether, decyl glycidyl ether, butyl glycidyl ether (such as n-butyl glycidyl ether), 1,2-epoxyhexane, epichlorohydrin, glycidyltrimethylammonium chloride, cyclopentene oxide, cyclohexene oxide, poly(ethylene glycol) diglycidyl ether, poly(propylene glycol) diglycidyl ether and poly(butylene glycol) diglycidyl ether. The third reactant may be (v) a polyfunctional reactant having a reactive amino group. By the term “polyfunctional reactant” we mean a reactant with at least two reactive groups. By the term “reactive group” we mean a group that reacts with the first reactant and / or the second reactant. At least one of the reactive groups is a reactive amino group. The other reactive groups in the polyfunctional reactant may be reactive amino groups, or may be reactive groups other than amino groups, such as hydroxy groups or carboxyl groups. Reactive amino groups are suitably primary amino groups or secondary amino groups. The polyfunctional reactant may comprise at least one reactive amino group and at least one hydroxy group. The polyfunctional reactant may be an alkanolamine or an alkoxylated alkanolamine. The polyfunctional reactant may comprise at least two reactive amino groups. The polyfunctional reactant may be an aliphatic diamine, a polyether diamine, or a polyalkylene polyamine. The polyfunctional reactant may comprise at least one reactive amino group and at least one carboxyl group. The polyfunctional reactant may be an amino acid, such as a naturally occurring amino acid. Examples of suitable polyfunctional reactants having at least one reactive amino group include ethanolamine, diethanolamine, ethylene diamine, coco propylene diamine, diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), a polyether diamine (preferably Jeffamine ED-600, Jeffamine ED-900, or Jeffamine ED-2003 which are commercially available), alanine, arginine, asparagine, aspartate, cysteine, glutamine, glutamate, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine. The third reactant may be (vi) a monoalcohol. Suitable monoalcohols may be aliphatic or aromatic. The aliphatic monoalcohol may be cycloaliphatic. The aliphatic monoalcohol may be saturated or unsaturated. The monoalcohol may contain from 2 to 40 carbon atoms, suitably from 4 to 30 carbon atoms, preferably from 6 to 20 carbon atoms, for example from 8 to 18 carbon atoms. The monoalcohol may be a fatty alcohol. Examples of suitable monoalcohols include hexanol, octanol, 2-ethylhexanol, decanol, dodecanol alcohol, myristyl alcohol, myristoleyl alcohol, palmityl alcohol, palmitoleyl alcohol, stearyl alcohol, oleyl alcohol, elaidyl alcohol, linoleyl alcohol, linolelaidyl alcohol, arachidyl alcohol, arachidonyl alcohol, behenyl alcohol, erucyl alcohol, benzyl alcohol, and choline chloride. Preferably, the monoalcohol is hexanol or oleyl alcohol. The third reactant may be (vii) a monofunctional reactant having a reactive amino group. Suitable monofunctional reactants having a reactive amino group have one reactive amino group and no other reactive groups. The monofunctional reactant may contain other functional groups that are not reactive groups, such as tertiary amino groups or ether groups. The monofunctional reactant may be an aliphatic monoamine (such as a fatty alkyl amine), an N,N-dialkylaminoalkylamine, or a polyether monoamine. The polyether monoamine suitably comprises a polyether backbone selected from polyethylene glycol (PEG), polypropylene glycol (PPG), or a copolymer of polyethylene glycol (PEG) and polypropylene glycol (PPG). The copolymer of PEG and PPG may be a block copolymer or a random copolymer. The polyether backbone is suitably capped at one end with the reactive amino group, and capped at the other end with an alkyl group (preferably a methyl group). The polyether monoamine suitably has a molecular weight of from 150 to 6000, preferably from 400 to 3000, for example from 600 to 2000. The polyether monoamine may have a weight average molecular weight of from 150 to 6000, preferably from 400 to 3000, for example from 600 to 2000. Examples of suitable monofunctional reactants having a reactive amino group include propylamine, dipropylamine, butylamine, hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, tallow alkyl amine, benzylamine, phenethylamine, 3-dimethylaminopropylamine (DMAPA), or Jeffamine M-1000 (which is commercially available). Preferably, the monofunctional reactant having a reactive amino group is selected from dodecylamine, N,N-dimethylaminopropylamine (DMAPA), or Jeffamine M-1000. The ester compounds may be prepared from the first, second and optionally third reactants by any suitable method, as would be known to the person skilled in the art. The esterification reaction will typically be conducted in the presence of a suitable esterification catalyst, such as tin(ll) ethylhexanoate, tin(ll) oxalate, p-toluenesulfonic acid, methanesulfonic acid, or sulfuric acid. Another suitable catalyst system comprises 1,8-diazabicyclo(5.4.0)undec-7-ene and dicyclohexylurea. The esterification reaction may be carried out for any suitable length of time, such as at least 1 hour, preferably at least 3 hours, for example at least 5 hours. The esterification reaction may be carried out at any suitable temperature, such as from 50 to 300°C, preferably from 100 to 200°C. References herein to a reactant are intended to refer to the compounds that react to form the ester compound and are not intended to include a catalyst used in the reaction. Suitable molar ratios of the first, second and optional third reactants may be used to prepare the ester compounds. Suitably, the ester compound is not further reacted after the reaction of the reactants. When the third reactant is used, the molar ratio of the first reactant to the sum of the second and third reactants is suitably from 1:1 to 1:5, such as from 1:1 to 1:3. Suitably, the ester compound may be the reaction product of reactants consisting essentially of or consisting of one or more first reactants, one or more second reactants, and optionally one or more third reactants, wherein the or each first reactant is a cyclic anhydride; the or each second reactant is a polyol, wherein at least one of the one or more second reactants is a nitrogen containing polyol and / or a polyol of formula (IVA): H-(OR18)q-OH (IVA) wherein each R18 is independently an optionally substituted alkylene group wherein the optional substituent is not hydroxy and q is an integer of at least 1; and the or each third reactant is selected from: (viii) polycarboxylic acids or reactive equivalents thereof; (ix) monocarboxylic acids or esters thereof; (x) hydroxycarboxylic acids or cyclic esters thereof; (xi) epoxide compounds; (xii) polyfunctional reactants having a reactive amino group; (xiii) monoalcohols; and (xiv) monofunctional reactants having a reactive amino group. Suitably, the ester compound may be the reaction product of reactants consisting essentially of or consisting of one or more first reactants, one or more second reactants, and optionally one or more third reactants, wherein the or each first reactant is a cyclic anhydride; the or each second reactant is a polyol, wherein at least one of the one or more second reactants is selected from ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,6-hexanediol, 1,12-dodecanediol, 2-ethyl-1,3,-hexanediol, 2,2-diethy 1-1,3-propanediol, 2,2-bis(hydroxymethyl)propionic acid, neopentyl glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, polypropylene glycol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol ethoxylate, N-methyl diethanolamine, N-butyl diethanolamine, diethanolamine, or derivatives (for example quaternary ammonium salts) of N-methyl diethanolamine or N-butyl diethanolamine; and the or each third reactant is selected from: (i) polycarboxylic acids or reactive equivalents thereof; (ii) monocarboxylic acids or esters thereof; (iii) hydroxycarboxylic acids or cyclic esters thereof; (iv) epoxide compounds; (v) polyfunctional reactants having a reactive amino group; (vi) monoalcohols; and (vii) monofunctional reactants having a reactive amino group. Suitably, the ester compound may be the reaction product of reactants consisting essentially of or consisting of one or more first reactants, one or more second reactants, and optionally one or more third reactants, wherein the or each first reactant is a cyclic anhydride; the or each second reactant is a polyol; and the or each third reactant is selected from: (i) polycarboxylic acids or reactive equivalents thereof; (ii) aliphatic monocarboxylic acids or esters thereof; (iii) hydroxycarboxylic acids or cyclic esters thereof; (iv) epoxide compounds; (v) polyfunctional reactants having a reactive amino group; (vi) monoalcohols; and (vii) monofunctional reactants having a reactive amino group. Suitably, the ester compound may be the reaction product of reactants consisting essentially of or consisting of one or more first reactants, one or more second reactants, and optionally one or more third reactants, wherein the or each first reactant is a cyclic anhydride; the or each second reactant is a polyol; and the or each third reactant is selected from: (i) polycarboxylic acids or reactive equivalents thereof; (ii) hydroxycarboxylic acids or cyclic esters thereof; (iii) epoxide compounds; (iv) polyfunctional reactants having a reactive amino group; (v) monoalcohols; and (vi) monofunctional reactants having a reactive amino group. Suitably, the ester compound may be the reaction product of reactants consisting essentially of or consisting of one or more first reactants, one or more second reactants, and optionally one or more third reactants, wherein the or each first reactant is a cyclic anhydride; the or each second reactant is a polyol; and the or each third reactant is selected from: (i) polycarboxylic acids or reactive equivalents thereof; (ii) monocarboxylic acids or esters thereof; (iii) hydroxycarboxylic acids or cyclic esters thereof; (iv) epoxide compounds; (v) polyfunctional reactants having a reactive amino group selected from ethanolamine, diethanolamine, ethylene diamine, coco propylene diamine, diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), a polyether diamine (preferably Jeffamine ED-600, Jeffamine ED-900, or Jeffamine ED-2003 which are commercially available), alanine, arginine, asparagine, aspartate, cysteine, glutamine, glutamate, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, or valine; (vi) monoalcohols; and (vii) monofunctional reactants having a reactive amino group selected from propylamine, dipropylamine, butylamine, hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, tallow alkyl amine, benzylamine, phenethylamine, 3-dimethylaminopropylamine (DMAPA), or Jeffamine M-1000. Suitably, the ester compound may be the reaction product of reactants consisting essentially of or consisting of one or more first reactants, one or more second reactants, and optionally one or more third reactants, wherein the or each first reactant is a cyclic anhydride; the or each second reactant is a polyol; and the or each third reactant is selected from: (i) polycarboxylic acids or reactive equivalents thereof; (ii) monocarboxylic acids or esters thereof; (iii) hydroxycarboxylic acids or cyclic esters thereof; (iv) epoxide compounds; and (v) monoalcohols. Suitably, the or each third reactant (when present) is a monocarboxylic acid or an ester thereof selected from hexanoic acid, octanoic acid, decanoic acid, lauric acid, myristic acid, myristoleic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, elaidic acid, linoleic acid, linolelaidic acid, arachidic acid, arachidonic acid, behenic acid, erucic acid, and esters (preferably methyl esters) thereof; and the second and third reactants are reacted in a molar ratio of from 1:2 to 2:1, such as from 1:2 to 1:1, preferably 1:1 or 1:1.5. Suitably, the or each third reactant (when present) is a fatty acid and the second and third reactants are reacted in a molar ratio of from 1:2 to 2:1, such as from 1:2 to 1:1, preferably 1:1 or1:1.5. Ratios refer to the total amounts of second reactants or third reactants if more than one second reactant or third reactant is present. Suitably, at least one of the first reactants may be a cyclic anhydride of formula (I) wherein at least one of R1 and R2 is a Ce-30, such as a Cs-24, alkyl or alkenyl (more preferably alkenyl) group (such as an alkenyl group derived from a terminal olefin or an internal olefin, preferably an internal olefin) and at least one of the second reactants may be castor oil. Suitably, at least one of the first reactants may be a cyclic anhydride of formula (I) wherein R1 is hydrogen and R2 is a Ce-30, such as a Cs-24, alkyl or alkenyl (more preferably alkenyl) group (such as an alkenyl group derived from a terminal olefin or an internal olefin, preferably an internal olefin) and at least one of the second reactants may be castor oil. Suitably, the first reactant may be a cyclic anhydride of formula (I) wherein R1 is hydrogen and R2 is a Ce-30, such as a Cs-24, alkyl or alkenyl (more preferably alkenyl) group (such as an alkenyl group derived from a terminal olefin or an internal olefin, preferably an internal olefin) and the second reactant may be castor oil. Suitably, the first reactant may be selected from nonenyl succinic anhydride, dodecenyl succinic anhydride, C15-18 internal olefin-derived alkenyl succinic anhydride, C16 internal olefin-derived alkenyl succinic anhydride, and C16 terminal olefin-derived alkenyl succinic anhydride and the second reactant may be castor oil. Suitably, the first reactant may be nonenyl succinic anhydride and the second reactant may be castor oil. Suitably, the first reactant may be selected from C15-18 internal olefin-derived alkenyl succinic anhydride, C16 internal olefin-derived alkenyl succinic anhydride, and C16 terminal olefin-derived alkenyl succinic anhydride and the second reactant may be castor oil. Suitably, the first reactant may be dodecenyl succinic anhydride and the second reactant may be castor oil. The dodecenyl succinic anhydride and the castor oil may be reacted in a molar ratio of from 10:1 to 1:10, such as from 2:1 to 1:2, preferably from 1.5:1 to 1:1.5. More preferably, the dodecenyl succinic anhydride and the castor oil may be reacted in a 1:1 molar ratio. Suitably, the first reactant may be selected from succinic anhydride, maleic anhydride, glutaric anhydride, C20-24 alkenyl succinic anhydride, nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, octadecyl succinic anhydride, octyl succinic anhydride, C15-18 internal olefin-derived alkenyl succinic anhydride, C16 internal olefin-derived alkenyl succinic anhydride, C16 terminal olefin-derived alkenyl succinic anhydride, a branched alkenyl succinic anhydride such as tetrapropenyl succinic anhydride or polyisobutenyl succinic anhydride, phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 1,2-naphthalic anhydride, 2,3-naphthalic anhydride, 1,8-naphthalic anhydride or homophthalic anhydride and the second reactant may be castor oil. The first reactant and second reactant may be reacted in a 1:1 molar ratio. Suitably, the first reactant may be selected from succinic anhydride, maleic anhydride, glutaric anhydride, C20-24 alkenyl succinic anhydride, nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, octadecyl succinic anhydride, octyl succinic anhydride, a branched alkenyl succinic anhydride such as tetrapropenyl succinic anhydride or polyisobutenyl succinic anhydride, phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 1,2-naphthalic anhydride, 2,3-naphthalic anhydride, 1,8-naphthalic anhydride or homophthalic anhydride and the second reactant may be castor oil. The first reactant and second reactant may be reacted in a 1:1 molar ratio. Suitably, the first reactant may be selected from C20-24 alkenyl succinic anhydride, nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, octadecyl succinic anhydride, or octyl succinic anhydride and the second reactant may be castor oil. The first reactant and second reactant may be reacted in a 1:1 molar ratio. Suitably, at least one of the first reactants may be a cyclic anhydride of formula (I) wherein least one of R1 and R2 is a C6-30, such as a Cs-24, alkyl or alkenyl (more preferably alkenyl) group (such as a C6-30, preferably Cs-24, alkenyl group derived from a terminal olefin or an internal olefin, preferably an internal olefin), or at least one of the first reactants may be a cyclic anhydride of formula (II) wherein R3 and R4 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group; and at least one of the second reactants may be selected from N-methyl diethanolamine, N-butyl diethanolamine, castor oil, tris(2-hydroxyethyl)methyl ammonium methylsulfate, PEG 200, 1,6-hexanediol, sorbitol, trimethylolpropane, or neopentyl glycol. Suitably, at least one of the first reactants may be a cyclic anhydride of formula (I) wherein least one of R1 and R2 is a C6-30, such as a Cs-24, alkyl or alkenyl (more preferably alkenyl) group (such as a C6-30, preferably Cs-24, alkenyl group derived from a terminal olefin or an internal olefin, preferably an internal olefin), or at least one of the first reactants may be a cyclic anhydride of formula (II) wherein R3 and R4 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group; and at least one of the second reactants may be selected from N-methyl diethanolamine, N-butyl diethanolamine, castor oil, tris(2-hydroxyethyl)methyl ammonium methylsulfate, PEG 200, 1,6-hexanediol, or sorbitol. Suitably, the ester compound may be the reaction product of reactants comprising a first reactant, one or more second reactants, and optionally a third reactant, wherein the first reactant is selected from dodecenyl succinic anhydride, octadecenyl succinic anhydride, or pyromellitic dianhydride; the one or more second reactants are selected from N-methyl diethanolamine, N-butyl diethanolamine, castor oil, tris(2-hydroxyethyl)methyl ammonium methylsulfate, PEG 200, 1,6-hexanediol, or sorbitol; and the third reactant is oleyl alcohol. The molar ratio of the first reactant and the one or more second reactants is preferably 1:1. When the third reactant is used, the molar ratio of the first, second and third reactants is suitably 1:1:1.5. Suitably, the ester compound may be the reaction product of reactants consisting essentially of or consisting of a first reactant, one or more second reactants, and optionally a third reactant, wherein the first reactant is selected from dodecenyl succinic anhydride, octadecenyl succinic anhydride, or pyromellitic dianhydride; the one or more second reactants are selected from N-methyl diethanolamine, N-butyl diethanolamine, castor oil, tris(2-hydroxyethyl)methyl ammonium methylsulfate, PEG 200, 1,6-hexanediol, or sorbitol; and the third reactant is oleyl alcohol. The molar ratio of the first reactant and the one or more second reactants is preferably 1:1. When the third reactant is used, the molar ratio of the first reactant, second and third reactants is suitably 1:1:1.5. Suitably, the ester compound may be the reaction product of reactants comprising a first reactant and one or more second reactants, wherein the first reactant is selected from nonenyl succinic anhydride, dodecenyl succinic anhydride (preferably 2-dodecen-1-yl succinic anhydride), or octadecenyl succinic anhydride; and the one or more second reactants are selected from N-methyl diethanolamine, N-butyl diethanolamine, castor oil, PEG 200, 1,6-hexanediol, sorbitol, trimethylolpropane, or neopentyl glycol. The molar ratio of the first reactant and the one or more second reactants is preferably 1:1. Suitably, the ester compound may be the reaction product of reactants consisting essentially of or consisting of a first reactant and one or more second reactants, wherein the first reactant is selected from nonenyl succinic anhydride, dodecenyl succinic anhydride (preferably 2-dodecen-1-yl succinic anhydride), or octadecenyl succinic anhydride; and the one or more second reactants are selected from N-methyl diethanolamine, N-butyl diethanolamine, castor oil, PEG 200, 1,6-hexanediol, sorbitol, trimethylolpropane, or neopentyl glycol. The molar ratio of the first reactant and the one or more second reactants is preferably 1:1. Preferably, the ester compound is the reaction product of reactants comprising: (i) dodecenyl succinic anhydride and N-methyl diethanolamine, preferably in a molar ratio of 1:1; (ii) dodecenyl succinic anhydride, castor oil, and tris(2-hydroxyethyl)methyl ammonium methylsulfate, preferably in a molar ratio of 1:0.6:0.4; (iii) dodecenyl succinic anhydride and N-butyl diethanolamine, preferably in a molar ratio of 1:1; (iv) octadecenyl succinic anhydride and N-butyl diethanolamine, preferably in a molar ratio of 1:1; (v) dodecenyl succinic anhydride, N-methyl diethanolamine, and castor oil, preferably in a molar ratio of 1:0.5:0.5; (vi) dodecenyl succinic anhydride and castor oil, preferably in a molar ratio of 1:1; (vii) dodecenyl succinic anhydride, N-butyl diethanolamine, and PEG 200, preferably in a molar ratio of 1:0.5:0.5; (viii) pyromellitic dianhydride, PEG 200 and oleyl alcohol, preferably in a molar ratio of 1:1:1.5; (ix) dodecenyl succinic anhydride, N-butyl diethanolamine, and 1,6-hexanediol, preferably in a molar ratio of 1:0.8:0.2; (x) octadecenyl succinic anhydride and N-methyl diethanolamine, preferably in a molar ratio of 1:1; or (xi) dodecenyl succinic anhydride, sorbitol, and 1,6-hexanediol, preferably in a molar ratio of 1:0.2:0.8. Preferably, the ester compound is the reaction product of reactants consisting essentially of or consisting of: (i) dodecenyl succinic anhydride and N-methyl diethanolamine, preferably in a molar ratio of 1:1; (ii) dodecenyl succinic anhydride, castor oil, and tris(2-hydroxyethyl)methyl ammonium methylsulfate, preferably in a molar ratio of 1:0.6:0.4; (iii) dodecenyl succinic anhydride and N-butyl diethanolamine, preferably in a molar ratio of 1:1; (iv) octadecenyl succinic anhydride and N-butyl diethanolamine, preferably in a molar ratio of 1:1; (v) dodecenyl succinic anhydride, N-methyl diethanolamine, and castor oil, preferably in a molar ratio of 1:0.5:0.5; (vi) dodecenyl succinic anhydride and castor oil, preferably in a molar ratio of 1:1; (vii) dodecenyl succinic anhydride, N-butyl diethanolamine, and PEG 200, preferably in a molar ratio of 1:0.5:0.5; (viii) pyromellitic dianhydride, PEG 200 and oleyl alcohol, preferably in a molar ratio of 1:1:1.5; (ix) dodecenyl succinic anhydride, N-butyl diethanolamine, and 1,6-hexanediol, preferably in a molar ratio of 1:0.8:0.2; (x) octadecenyl succinic anhydride and N-methyl diethanolamine, preferably in a molar ratio of 1:1; or (xi) dodecenyl succinic anhydride, sorbitol, and 1,6-hexanediol, preferably in a molar ratio of 1:0.2:0.8. Preferably, the ester compound is the reaction product of reactants comprising: (i) dodecenyl succinic anhydride (preferably 2-dodecen-1 -yl succinic anhydride) and castor oil, preferably in a molar ratio of 1:1; (ii) octadecenyl succinic anhydride and N-methyl diethanolamine, preferably in a molar ratio of 1:1; (iii) nonenyl succinic anhydride and PEG 200, preferably in a molar ratio of 1:1; (iv) dodecenyl succinic anhydride (preferably 2-dodecen-1-yl succinic anhydride) and trimethylolpropane, preferably in a molar ratio of 1:1; (v) dodecenyl succinic anhydride (preferably 2-dodecen-1-yl succinic anhydride), sorbitol, and 1,6-hexanediol, preferably in a molar ratio of 1:0.25:0.75; (vi) dodecenyl succinic anhydride (preferably 2-dodecen-1-yl succinic anhydride) and N-methyl diethanolamine, preferably in a molar ratio of 1:1; (vii) nonenyl succinic anhydride and castor oil, preferably in a molar ratio of 1:1; (viii) dodecenyl succinic anhydride (preferably 2-dodecen-1-yl succinic anhydride), N-butyI diethanolamine, and PEG 200, preferably in a molar ratio of 1:0.5:0.5; or (ix) dodecenyl succinic anhydride (preferably 2-dodecen-1-yl succinic anhydride), N-butyl diethanolamine, and neopentyl glycol, preferably in a molar ratio of 1:0.5:0.5. Preferably, the ester compound is the reaction product of reactants consisting essentially of or consisting of: (i) dodecenyl succinic anhydride (preferably 2-dodecen-1 -yl succinic anhydride) and castor oil, preferably in a molar ratio of 1:1; (ii) octadecenyl succinic anhydride and N-methyl diethanolamine, preferably in a molar ratio of 1:1; (iii) nonenyl succinic anhydride and PEG 200, preferably in a molar ratio of 1:1; (iv) dodecenyl succinic anhydride (preferably 2-dodecen-1-yl succinic anhydride) and trimethylolpropane, preferably in a molar ratio of 1:1; (v) dodecenyl succinic anhydride (preferably 2-dodecen-1-yl succinic anhydride), sorbitol, and 1,6-hexanediol, preferably in a molar ratio of 1:0.25:0.75; (vi) dodecenyl succinic anhydride (preferably 2-dodecen-1-yl succinic anhydride) and N-methyl diethanolamine, preferably in a molar ratio of 1:1; (vii) nonenyl succinic anhydride and castor oil, preferably in a molar ratio of 1:1; (viii) dodecenyl succinic anhydride (preferably 2-dodecen-1-yl succinic anhydride), N-butyI diethanolamine, and PEG 200, preferably in a molar ratio of 1:0.5:0.5; or (ix) dodecenyl succinic anhydride (preferably 2-dodecen-1-yl succinic anhydride), N-butyl diethanolamine, and neopentyl glycol, preferably in a molar ratio of 1:0.5:0.5. Preferably, the ester compound is the reaction product of reactants comprising: (i) dodecenyl succinic anhydride (preferably 2-dodecen-1 -yl succinic anhydride) and castor oil, preferably in a molar ratio of 1:1; or (ii) octadecenyl succinic anhydride and N-methyl diethanolamine, preferably in a molar ratio of 1:1. Preferably, the ester compound is the reaction product of reactants consisting essentially of or consisting of: (i) dodecenyl succinic anhydride (preferably 2-dodecen-1 -yl succinic anhydride) and castor oil, preferably in a molar ratio of 1:1; or (ii) octadecenyl succinic anhydride and N-methyl diethanolamine, preferably in a molar ratio of 1:1. Preferably, the ester compound is the reaction product of reactants comprising, or of reactants consisting essentially of or consisting of, dodecenyl succinic anhydride and castor oil, preferably in a molar ratio of 1:1, and wherein the ester compound has a number average molecular weight of from 2,000 to 3,000 Daltons and / or a polydispersity index of from 1 to 4, such as from 1.1 to 2, preferably from 1.5 to 1.6. The ester compound may be a polymer. The reactants used to prepare the ester compound may be monomers. The first reactant may be a first monomer, the second reactant may be a second monomer, and the third reactant (when present) may be a third monomer. Thus, the ester compound may be a polymer comprising, consisting essentially of, or consisting of repeat units derived from the one or more first reactants, repeat units derived from the one or more second reactants, and optionally repeat units derived from one or more third reactants as defined herein. Typically, the polymer is a polyester. The polymer may be a random copolymer or a block copolymer, in particular when there is more than one first reactant or more than one second reactant. Preferably, the polymer is a random copolymer. The polymer formed from the first, second and optional third reactants may comprise a suitable number of total monomer units (i.e. repeat units). For example, the polymer may comprise at least 4 monomer units. In other words, the polymer may comprise a total of at least 4 monomer units including the first, second and optional third monomers. Suitably, the polymer may comprise from 4 to 50 monomer units, preferably from 4 to 30 monomer units. Suitably, the ester compound has a number average molecular weight of from 1,000 to 150,000 Daltons, preferably from 1,000 to 15,000 Daltons (for example from 2,000 to 7,000 or from 2,000 to 3,000 Daltons). Suitably, the ester compound has a polydispersity index of from 1 to 4, such as from 1.1 to 2, preferably from 1.5 to 1.6. The polydispersity index of an ester compound is given by the ratio of Mwto Mn (Mw / Mn), wherein Mw is the weight-average molecular weight and Mn is the number average molecular weight. Preferably, the ester compound is substantially free of silicon atoms. By substantially free of silicon atoms we mean that the ester compound contains less than 1 wt% of silicon in the ester compound, preferably less than 0.5 wt% of silicon in the ester compound. More preferably, the ester compound is free of silicon atoms, by which we mean that it is not possible to detect silicon in the ester compound. Suitable methods of measuring the amount of silicon in an ester compound are well known to those skilled in art and include elemental analysis and inductively coupled plasma (ICP) spectroscopy. Preferably, the ester compound is substantially free of fluorine atoms. The ester compound may be substantially free of halogen atoms. By substantially free of fluorine or halogen atoms we mean that the ester compound contains less than 1 wt% of fluorine or halogen in the ester compound, preferably less than 0.5 wt% of fluorine or halogen in the ester compound. More preferably, the ester compound is free of fluorine atoms. The ester compound may be free of halogen atoms. By free of fluorine or halogen atoms we mean that it is not possible to detect fluorine or halogen in the ester compound. Suitable methods of measuring the amount of fluorine or halogen in a compound are well known to those skilled in art and include elemental analysis and inductively coupled plasma (ICP) spectroscopy. Preferably, the ester compound is substantially free of quaternary ammonium moieties. By substantially free of quaternary ammonium moieties we mean that the ester compound contains less than 1 wt% of quaternary nitrogen atoms in the ester compound, preferably less than 0.5 wt% of quaternary nitrogen atoms in the ester compound. More preferably, the ester compound is free of quaternary ammonium moieties, by which we mean that it is not possible to detect quaternary ammonium moieties in the ester compound. Preferably, the ester compound is substantially free of amide moieties. By substantially free of amide moieties we mean that the ester compound contains less than 1 wt% of amide groups (NC(=O)) in the ester compound, preferably less than 0.5 wt% of amide groups in the ester compound. More preferably, the ester compound is free of amide moieties, by which we mean that it is not possible to detect amide moieties in the ester compound. The ester compound as disclosed herein may be formulated as a component of a composition, such as a composition according to the third aspect. In other words, the ester compound may be comprised in a composition, such as a composition according to the third aspect. Suitably, the ester compound may be comprised in a composition, wherein the composition additionally comprises one or more suitable additional components. The composition of the third aspect is suitable for or intended for treating a keratinous material (especially hair). The composition of the third aspect may, in use, provide a change or benefit to a keratinous material (especially hair), for example by enhancing at least one property of the keratinous material (especially hair) as discussed above in relation to the first and second aspects. Thus, the composition of the third aspect may, when contacted with keratinous material (especially hair) change, provide a beneficial effect to or enhance any suitable property of the keratinous material (especially hair). The property of the keratinous material (especially hair) that may be changed, beneficially affected or enhanced may be one or more of the properties discussed herein in relation to the first and second aspects. The change, benefit or enhancement provided by the composition may be temporary, permanent or semi-permanent. In some preferred embodiments the composition of the third aspect may provide a longer lasting benefit to the keratinous material (especially hair), for example a wash-durable benefit. The composition of the third aspect may, upon contact with the keratinous material (especially hair), benefit the keratinous material (especially hair) by providing a conditioning effect thereto. Any suitable conditioning effect may be provided. The composition of the third aspect may, upon contact with keratinous material (especially hair), benefit the keratinous material (especially hair) by providing a reduction in frizziness thereto, i.e. by providing an anti-frizz effect. The composition of the third aspect may, for example, be an anti-frizz composition, such as a leave in or rinse off anti-frizz composition. The composition of the third aspect may, upon contact with keratinous material (especially hair), benefit the keratinous material (especially hair) by providing improved shine or gloss thereto. The composition of the third aspect may, upon contact with keratinous material (especially hair), benefit the keratinous material (especially hair) by providing improved softness thereto. The composition of the third aspect may, upon contact with keratinous material (especially hair), benefit the keratinous material (especially hair) by providing improved silkiness thereto. The composition of the third aspect may, upon contact with keratinous material (especially hair), benefit the keratinous material (especially hair) by providing improved moisture levels (or moisturisation) thereto. The composition of the third aspect may, upon contact with keratinous material (especially hair), benefit the keratinous material (especially hair) by providing improved thermal durability thereto. The composition of the third aspect may, upon contact with keratinous material (especially hair), benefit the keratinous material (especially hair) by providing improved combability thereto. The composition of the third aspect may, upon contact with keratinous material (especially hair), benefit the keratinous material (especially hair) by providing protection to the keratinous material (especially hair) against damage. For example the composition of the third aspect may, upon contact with keratinous material (especially hair), protect against damage from heat or sunlight (for example by providing UV stability or protection). The composition of the third aspect may, upon contact with keratinous material (especially hair), benefit the keratinous material (especially hair) by providing improved smoothness thereto. The composition of the third aspect may, upon contact with keratinous material (especially hair), benefit the keratinous material (especially hair) by reducing the drying time of the keratinous material (especially hair). Those skilled in the art will appreciate that it is possible to confer one or more benefits to a keratinous material (especially hair) from a single product containing the ester compound as defined herein. Thus, compositions that may provide such combinations of benefits are also covered in the invention. The form and nature of the composition of the third aspect will depend on the intended use thereof. The composition of the third aspect may be provided in any suitable form, for example that is suitable for application to a keratinous material (especially hair). For example, the composition may be in the form of an aerosol, gel, paste, cream, mousse, spray or wax. It may be in the form of a liquid composition. Such compositions may be in the form of a solution, dispersion or emulsion. The composition may be provided as a solid composition, for example as a powder or as a bar. In some embodiments a concentrate composition may be provided, which for example may be for dilution prior to use or for use in manufacturing a consumer product. In some embodiments the composition of the third aspect may be a precursor composition to be mixed with one or more further components prior to contact with the keratinous material (especially hair). The composition may be a concentrate composition. Typically, a concentrate composition may be diluted prior to use. Such a concentrate composition may comprise at least 10 wt%, such as at least 20 wt%, at least 30 wt%, at least 40 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, or at least 80 wt% of the ester compound. Such a concentrate composition may comprise 99 wt% or less, such as 95 wt% or less, for example 90 wt% or less of the ester compound. For example, the concentrate composition may comprise from 10 to 99 wt%, preferably from 20 to 95 wt%, for example from 50 to 90 wt% of the ester compound. References herein to the amount of ester compound in the composition of the third aspect are intended to refer to the total of the or each ester compound as defined herein that is included in the composition. In another embodiment, the composition may be suitable for directly contacting with a keratinous material (for example without dilution prior to use). In this case, the composition may comprise at least 0.1 wt%, such as at least 0.5 wt%, at least 1 wt%, at least 2 wt%, or at least 4 wt% of the ester compound. Such a composition may comprise less than 10 wt% of the ester compound, such as 8 wt% or less or 5 wt% or less of the ester compound. For example, the composition may comprise from 0.1 to 5 wt%, preferably from 0.5 to 5 wt%, of the ester compound. Suitably the composition of the third aspect is substantially free of silicon atoms. By substantially free of silicon atoms we mean that the composition contains less than 1 wt%, preferably less than 0.5 wt%, of silicon in the composition. More preferably, the composition is free of silicon atoms, by which we mean that it is not possible to detect silicon in the composition. Suitable methods of measuring the amount of silicon in a composition are well known to those skilled in art and include elemental analysis and inductively coupled plasma (ICP) spectroscopy. The composition of the third aspect may be a shampoo or a bodywash, preferably a shampoo. The shampoo may be a leave in or rinse out shampoo, preferably a leave in shampoo. The composition of the third aspect may be suitable for application to a human or an animal. The composition may be an animal (for example pet) care composition. The composition may comprise one or more further additional components. Suitable additional components are those typically used in personal care compositions (especially hair care compositions) and are known to the person skilled in the art. The compositions of the third aspect may comprise different additional components depending on the intended use thereof. The additional components may be included to provide different properties to the keratinous material (especially hair) as provided by the ester compound defined herein in use thereof, and / or to provide an enhancement to a property as provided by the ester compound as defined herein. The one or more suitable further additional components may be included in the composition of the third aspect in any suitable amount, as would be appreciated by a person skilled in the art. The relative ratios of the components and the formulation of such compositions would be within the competence of the skilled person. For example, the one or more further additional components (when present) may be included in the composition in an amount of from 0.01 to 10 wt% of the composition. For example, the composition may further comprise one or more carriers or solvents. Any suitable carrier or solvent may be included in the composition. A suitable carrier or solvent may, for example, be selected from one or more of water, monohydric-alcohols (for example ethanol, propanol, isopropanol, isobutanol tertiary-butanol and fatty alcohols), polyhydric alcohols (for example alkylene glycols and poly(alkylene glycols)), sugar alcohols (for example sorbitol), low viscosity / volatile silicones, hydrocarbon solvents (for example isododecane and mineral oils), propylene carbonate, benzyl alcohol, aliphatic or aromatic esters (for example vegetable oils, isopropyl myristate and C12-15 alkyl benzoate), and perfluorocarbon solvents. Mixtures of the carriers and / or solvents may be used. The composition of the third aspect may comprise any suitable amount of the one or more carriers or solvents, for example from 60 to 99.9 wt%, preferably from 65 to 90 wt%. The composition of the third aspect may be an aqueous composition. In this case water is suitably the major solvent present in the composition. In some embodiments water provides for at least 50 wt% of all solvents present in the composition, preferably at least 60 wt%, more preferably at least 70 wt%, suitably at least 80 wt%, for example at least 90 wt% or at least 95 wt%. In some embodiments one or more further water miscible solvents may be present. Examples of suitable water miscible solvents include monohydric and polyhydric alcohols, for example ethanol, glycerol and isopropanol. When the carrier or solvent comprises water, the composition may be in the form of an emulsion. The composition of the third aspect may not be aqueous. In this case the composition may comprise a solvent or carrier that is an oleophilic material. For example, the composition may comprise a solvent selected from one or more higher fatty alcohols, a mineral oil and a vegetable oil. The composition of the third aspect may, for example, further comprise one or more propellants. Any suitable propellant may be included in the composition. A suitable propellant may be a liquifiable gas especially those selected from a chlorofluorocarbon, a hydrofluorocarbon (such as hydrofluorocarbon 152A), n-propane, isopropane, n-butane, isobutane, dimethyl ether, dimethoxymethane, ethanol / water blends, dimethoxyethane, compressed air, compressed nitrogen, and compressed carbon dioxide. Preferably (when present) the propellant may be selected from one or more of n-propane, isopropane, n-butane, isobutane, dimethyl ether, dimethoxymethane, dimethoxyethane, compressed air and compressed carbon dioxide. Suitable further additional components may include one or more of aesthetic modifying agents, anti-dandruff agents, anti-static agents, anti-oxidants, chelating agents, conditioning agents, costyling agents, electrolytes, film forming agents, foaming agents, fragrances, fragrance solubilisers, hair colouring agents, hydrotropic agents, additional moisturising agents, neutralising agents for styling polymers, rheology modifiers and pH adjusters, other active agents, pearlising agents, penetration enhancing agents, pH adjusting agents, plasticisers, preservatives, product colouring agents, scalp benefit agents, additional shine agents, slip agents, styling agents, texturising agents, thermal protection agents, UV absorbers, viscosifying agents, agents to combat colour loss, sebum reduction agents, anti-itch agents, hair fall reduction agents, hair growth promoters, and wetting agents. Preferably, the further additional components may include one or more of anti-dandruff agents, anti-static agents, anti-oxidants, chelating agents, co-styling agents, electrolytes, film forming agents, foaming agents, fragrances, fragrance solubilisers, hair colouring agents, hydrotropic agents, additional moisturising agents, neutralising agents for styling polymers, rheology modifiers and pH adjusters, other active agents, pearlising agents, penetration enhancing agents, pH adjusting agents, plasticisers, preservatives, product colouring agents, scalp benefit agents, additional shine agents, slip agents, styling agents, texturising agents, UV absorbers, viscosifying agents, sebum reduction agents, anti-itch agents, hairfall reduction agents, hair growth promoters, and wetting agents. When the composition of the third aspect is provided as a solid composition, suitable additional components may additionally include one or more of structuring aids, fillers, binding agents, anti-mushing / sloughing agents, anti-cracking / hardening agents, sensory property agents (such as cooling agents and warming agents), scalp exfoliant particles, beads or encapsulates (which particles may be physically robust in the solid form but rupture on contact with water). Examples of suitable aesthetic modifying agents may include dimethicone crosspolymer, dimethicone / vinyl dimethicone crosspolymer, dimethicone / phenyl vinyl dimethicone crosspolymer, vinyl dimethicone / lauryl dimethicone crosspolymer, lauryl polydimethylsiloxyethyl dimethicone / bis-vinyl dimethicone crosspolymer, alkyl silicones, stearoxytrimethylsilane, ethylene - dimethicone copolymer, polyethylsiloxanes, alkyl silicones including caprylyl methicone, lauryl methicone and stearoxymethicone. Preferably however the composition of the third aspect is substantially free or free of silicon atoms, such that preferably the composition does not include the aforementioned aesthetic modifying agents. Examples of suitable anti-dandruff agents may include piroctone olamine, zinc oxide, zinc pyrithione(for example in combination with zinc sulfate), essential oils (such as clove, cinnamon and oregano), ketoconazole, climbazole, selenium sulfide, octopirox and sulfur. Examples of suitable sebum reduction agents include glycolipids, starches and tapioca, Examples of suitable anti-itch agents include histamine-based agents. Examples of suitable hair growth promoters include stimulants such as caffeine, minoxidil, and dimethylglycine. Examples of suitable anti-static agents may include behentrimonium chloride, behentrimonium methosulfate, cetrimonium bromide, cetrimonium chloride, laurtrimonium chloride and olealkonium chloride. Examples of suitable anti-oxidants may include BHT (butylated hydroxytoluene), BHA (butylated hydroxyanisole, tocopherol, vitamin E and tocopheryl acetate. Examples of suitable chelating agents may include ethylenediaminetetraacetic acid (EDTA), ethylenediamine- / \ / , / \ / '-disuccinic acid (EDDS), imido disuccinic acid (IDS), glutamic acid N,N-diacetic acid (GLDA), hydroxyethylidene diphosphonic acid (HEDP), diethylenetriamine penta(methylene phosphonic acid) (DTPMP), methylglycinediacetic acid (MGDA) and salts thereof, for example disodium EDTA and tetrasodium EDTA. Examples of suitable conditioning agents may include polyquaternium crosspolymer-3, stearamidopropyl dimethylamine, bisamino PEG / PPG-41 / 3 aminoethyl PG-propyl dimethicone, cyclopentasiloxane, olealkonium chloride, phenyl trimethicone, polydimethylsiloxane, polysilicone-15 and vinyl dimethicone / methicone silsesquioxane crosspolymers, : Guar hydroxypropyltrimonium Chloride [Activsoft C14 and Activsoft C17], tetralkyl ammonium halides e.g. Behentrimonium chloride, Cocotrimonium chloride, Cetethyldimonium bromide, Dibehenyldimonium chloride, Dihydrogenated tallow benzylmonium chloride, disoyadimonium chloride, Ditallowdimonium chloride, Hydroxycetyl hydroxyethyl dimonium chloride, Hydroxyethyl Behenamidopropyl dimonium chloride, Hydroxyethyl Cetyldimonium chloride, Hydroxyethyl tallowdimonium chloride, myristalkonium chloride, PEG-2 Oleamonium chloride, PEG-5 Stearmonium chloride, PEG- 15 cocoyl quaternium 4, PEG-2 stearalkonium 4, lauryltrimonium chloride, Quatemium-16, Quatemium-18, lauralkonium chloride, olealkonium chloride, cetylpyridinium chloride, Polyquatemium-5, Polyquaternium-6, Polyquaternium-7 Polyquaternium-10, polyquaternium-11, Polyqu ate mi um-22, Polyquatemium-37, Polyquaternium-39, polyquaternium-46, Polyquaternium-47, polyquaternium-55, cetyl trimonium chloride, cetrimonium bromide, dilauryldimonium chloride, cetalkonium chloride, dicetyldimonium chloride, soyatrimonium chloride, stearyl octydimonium methosulfate, behentrimonium methosulfate (18-MEA), and stearalkonium chloride. Preferably however the composition of the third aspect is substantially free or free of silicon atoms, such that preferably the composition does not include any aforementioned conditioning agents that include silicon. Examples of suitable co-styling agents may include acrylates crosspolymer-3, acrylates / octylacrylamide copolymer, acrylates / t-butylacrylamide copolymer, butyl ester of PVM / MA copolymer, crotonic acid / vinyl C8-12 isoalkyl estersA / A / bis-vinyldimethicone copolymer, methacryloyl ethyl betaine / acrylates copolymer, octylacrylamide / acrylates / butylaminoethyl methacrylate copolymer, PEG-150 / decyl alcohol / SMDi copolymer, AMP-acrylates copolymer, polyvinylcaprolactam, PVP, sodium polyacrylate, VA / crotonates / vinyl neodecanoate copolymer, vinyl caprolactamA / P / dimethylaminoethyl methacrylate copolymer, VP / dimethylaminoethylmethacrylate copolymer, VP / DMAPA acrylates copolymer, VPA / A copolymer, polyquaternium-11, polyquaternium-37, polyquaternium-46 and polyquaternium-55. Examples of suitable film forming agents may include polymers sold under the Amphomer trade name such as Amphomer® LV-71, and latex polymers. Foaming agents may be present when the composition is in the form of a mousse. Examples of suitable foaming agents may include behentrimonium chloride, behentrimonium methosulfate, behenyl alcohol, C14-16 olefin sulfonate, ceteareth-2, ceteareth-20, ceteareth-25, cetearyl alcohol, cetrimonium bromide, cetrimonium chloride, cetyl alcohol, cocamidopropyl betaine, alkyl glucosides (such as decyl glucoside, coco glucoside and lauryl glucoside), glycerol stearate, laureth-3, laureth-7, laurtrimonium chloride, lauryl alcohol, myristyl alcohol, olealkonium chloride, oleth-20, oleth-5, palmitic acid, PEG-100 stearate, polyglyceryl-3 stearate, polysorbate-20, PPG-15 stearyl ether, rhamnolipids, sophorolipids, steareth-2, steareth-21, stearic acid and stearyl alcohol. A suitable fragrance may be Parfum. Examples of suitable fragrance solubilisers may include PEG-40 hydrogenated castor oil, polysorbate-20 and polysorbate-80. Examples of suitable hydrotropic agents may include benzene sulfonate. Examples of suitable hair colouring agents may include acid violet 43, basic red 76, basic blue 99, basic brown 16, basic yellow 87, HC yellow no. 4, disperse red 11 and henna. Examples of suitable additional moisturising agents may include glycerin, panthenol and derivatives thereof, propanediol, propylene glycol, petrolatum, silicones, long chain esters, cationic polymers, alkanes, vegetable oils and urea. Suitable additional moisturising agents may moisturise the fibrous substrate (especially hair) and / or the skin on which the fibrous substrate may grow. Examples of suitable neutralising agents for styling polymers, rheology modifiers and pH adjusters may include aminomethyl propanol, potassium hydroxide, sodium hydroxide, tetrahydroxypropyl ethylenediamine, triethanolamine, triisopropanolamine and tromethane. Other suitable active agents may include plant extracts, keratin hydrolysate, amino acids (such as arginine, aspartine, aspartic acid, glutamine, glutamic acid, histidine, lysine, serine, wheat amino acids and silk amino acids) and salts thereof, and niacinamide. Such suitable active ingredients may act to protect, strengthen and / or smooth keratinous material (such as hair). Examples of suitable pearlising agents may include fatty alcohols (such as cetearyl alcohol) and fatty acid glycerol esters (especially glycerol monostearate and glycerol distearate). Examples of suitable penetration enhancing agents may include propylene carbonate and benzyl alcohol. Examples of suitable pH adjusting agents may include lactic acid, sodium hydroxide, sodium phosphate, citric acid, sodium bicarbonate, sodium hydrogen carbonate and salts and buffers thereof. The pH of the composition will depend on the intended use thereof. However preferably the composition has a pH of from 3 to 9, preferably from 3.5 to 8, more preferably from 4 to 7, preferably from 4 to 6. Examples of suitable plasticisers may include bis-diglyceryl polyacyladipate-2, cetearyl octanoate, dibutyl phthalate, dicaprylyl maleate, diethyl phthalate, diethylhexyl adipate, diisopropyl adipate, diisopropyl dimer dilinoleate, ethylhexyl palmitate, glycerin, isopropyl myristate, lauryl pyrrolidone, octyl pyrrolidone, panthenol and derivatives, PEG-12 dimethicone, PPG-12 dimethicone, propanediol, propylene glycol, stearyl stearate and triethyl citrate. Examples of suitable preservatives may include ethylhexyl glycerin, caprylyl glycol, DMDM hydantoin (1,3-bis(hydroxymethyl)-5,5-dimethylimidazolidine-2,4-dione), phenoxyethanol, sodium benzoate, potassium sorbate, methyl paraben and caprylhydroxamic acid. Examples of suitable product colouring agents may include charcoal powder, Cl 42090 and Cl 14700. Examples of suitable additional shine agents may include amodimethicone, bisamino PEG / PPG-41 / 3-aminoethyl PG-propyl dimethicone, cyclopentasiloxane, phenyl trimethicone, polydimethylsiloxane, polysilicone-15, diphenylsiloxy phenyl trimethicone, diphenyl dimethicone, caprylic / capric triglycerides, mineral or natural oils, alkyl benzoates and vinyl dimethicone / methicone silsesquioxane crosspolymers. Preferably however the composition of the third aspect is substantially free or free of silicon atoms, such that preferably the composition does not include any aforementioned shine agents that include silicon. Thus, preferably the shine agents may include one or more of caprylic / capric triglycerides, mineral or natural oils, and alkyl benzoates. Examples of suitable slip agents may include PEG-12, PEG-14M and PEG-45M. Examples of suitable styling agents may include beeswax, candellis wax, candellis wax esters, ceresin, copernicia cerifera wax, hydrogenated palm oil, kaolin, microcrystalline wax, ozokerite, petrolatum, paraffin, mineral oil, polyethylene, pumice, rice bran wax, shea butter, silica silylate and synthetic beeswax. Examples of suitable texturising agents may include beeswax, behenyl alcohol, bis-diglyceryI polyacyladipate-2, C13-14 isoalkane, candellia wax, candellia wax esters, caprylic / capric triglyceride, ceresin, cetearyl alcohol, cetearyl octanoate, cetyl alcohol, copernicia cerifera wax, dibutyl phthalate, dicaprylyl maleate, diethyl phthalate, diethylhexyl adipate, diisopropyl adipate, lanolin (and for example lanolin replacements), ethylhexyl palmitate, glycerin, hydrogenated palm oil, isohexadecane, isopropyl myristate, kaolin, lauryl alcohol, microcrystalline wax, myristyl alcohol, ozokerite PEG-12 dimethicone, petrolatum, paraffin, mineral oil, PEG-12, PEG-14M, PEG-45M, polyethylene, polyquaternium crosspolymer-3, polysorbate-20, PPG-12 dimethicone, pumice, rice bran wax, shea butter, silica, silica silylate, stearamidopropyl dimethylamine, stearyl alcohol, stearyl stearate, synthetic beeswax and triethyl citrate. Examples of suitable thermal protection agents may include bisamino PEG / PPG-41 / 3 aminoethyl PG-propyl dimethicone. Preferably however the composition of the third aspect is substantially free or free of silicon atoms, such that preferably the composition does not include the aforementioned thermal protection agent. UV absorbers may act to protect the keratinous material (such as hair) and / or the composition. Examples of suitable UV absorbers may include benzophenone-4, ethylhexyl dimethyl, PABA (4-amino parabenzoic acid), PABA derivates (such as PEG-25 ester derivates of PABA) and ethylhexyl methoxycinnamate. Examples of suitable viscosifying agents may include behenyl alcohol, cetearyl alcohol, cetyl alcohol, lauryl alcohol, myristyl alcohol and stearyl alcohol. Examples of suitable wetting agents may include ceteath-10 phosphate, dicetyl phosphate, lauryl pyrrolidone, octyl pyrrolidone, potassium cetyl phosphate, PPG-5-ceteth-20, sodium laureth sulfate and trilaureth-4 phosphate. Examples of suitable electrolytes may include ionic compounds such as metal salts selected from sodium chloride, sodium sulfate, potassium chloride, potassium sulfate, sodium phosphate, disodium phosphate, potassium phosphate, dipotassium phosphate, sodium isethionate, sodium methyl isethionate, sodium lactate, sodium citrate and non-metallic salts, for example, ammonium chloride, ammonium citrate and ammonium lactate. Examples of suitable scalp benefit agents may include coconut oil and argan oils. Examples of suitable anti-cracking / hardening agents may include sodium lactate, hydrogenated vegetable oil, hydrogenated castor oil and polyethylene glycol. A suitable anti-mushing / sloughing agent may be aluminium triformate. Examples of suitable agents to combat colour loss may include a hydroxy-substituted aldehyde, such as 2-hydroxydecanal, 2-hydroxydodecanal, 2-hydroxytetradecanal, 2-hydroxyhexanal, 2-hydroxyoctanal, 2-hydroxypropanal, glyceraldehyde, 6-hydroxyhexanal, 3-hydroxypropanal, 4-hydroxy-but-2-enal, 2-hydroxybutanal, 3-hydroxybutanal and 4-hydroxybutanal. A preferred agent to combat colour loss is 2-hydroxyoctanal. The composition of the third aspect may further comprise one or more surfactants, especially when the composition is a bodywash or a shampoo. Any suitable surfactant may be included in the composition. A suitable surfactant may, for example, be selected from one or more anionic, non-ionic, cationic and / or amphoteric surfactants. The anionic surfactant (when present) may be selected from one or more of a sulfate surfactant (such as a mono- or di-alkyl sulfate or alkyl ether sulfate), a sulfonate surfactant, a phosphate surfactant, a sulfosuccinate surfactant, a sulfoacetate surfactant, an isethionate surfactant, an amino acid surfactant (such as a glutamate, alaninate, sarcosinate or glycinate surfactant), a taurate surfactant, a fatty acid soap, an alkyl ether carboxylate and a lactylate surfactant. Particularly exemplary salts of the above, where applicable, are the sodium, potassium, ammonium, magnesium and triethanolamine salts. Where the anionic surfactants include one or more sulfate surfactants, these may suitably be selected from one or more of an alkali metal salt of a mono- or di-alkyl sulfate and / or a mono- or di-alkyl ether sulfate, such as sodium lauryl sulfate, sodium coco sulfate and / or sodium lauryl ether sulfate (sodium laureth sulfate). Where the anionic surfactants include one or more sulfonate surfactants, these may suitably be selected from one or more of an alkyl sulfonate, an alkyl aryl sulfonate, a primary alkane disulfonate, an alkene sulfonate, a hydroxyalkane sulfonate, an alkyl glyceryl ether sulfonate, an alpha-olefin sulfonate, a sulfonate of an alkylphenolpolyglycol ether, an alkyl sulfosuccinate, an alkyl ether sulfosuccinate, an sulfoacetate, and salts thereof. The sulfonate surfactants are suitably alkali metal salts of alkyl sulfonates, alkyl aryl sulfonates and / or alpha-olefin sulfonates. Preferred sulfonates include alpha-olefin sulfonates such as sodium C14-C16 olefin sulfonate. Examples of suitable sulfate and sulfonate surfactants include alkyl glyceryl ether sulfonate, ammonium lauryl sulfate, ammonium laureth sulfate, triethylamine lauryl sulfate, triethylamine laureth sulfate, triethanolamine lauryl sulfate, triethanolamine laureth sulfate, monoethanolamine lauryl sulfate, monoethanolamine laureth sulfate, diethanolamine lauryl sulfate, diethanolamine laureth sulfate, lauric monoglyceride sodium sulfate, sodium lauryl sulfate, sodium laureth sulfate, potassium lauryl sulfate, potassium laureth sulfate, ammonium cocoyl sulfate, ammonium lauroyl sulfate, sodium cocoyl sulfate, sodium lauroyl sulfate, potassium cocoyl sulfate, potassium lauryl sulfate, triethanolamine lauryl sulfate, triethanolamine lauryl sulfate, monoethanolamine cocoyl sulfate, monoethanolamine lauryl sulfate, sodium tridecyl benzene sulfonate, sodium dodecyl benzene sulfonate, and combinations thereof. Sodium laureth sulfate is preferred. Where the anionic surfactants include one or more isethionate surfactants, they preferably include alkali salts of acyl isethionate surfactants. Suitable acyl isethionate surfactants are compounds of formula R23COOCHR24CHR25SO3_M+ wherein R23 represents an optionally substituted C3-C34 hydrocarbyl group, R24 and R25 each independently represent hydrogen or a C1-C4 alkyl and M+ represents a cation. Preferred acyl isethionate surfactants include sodium cocoyl isethionate, sodium lauroyl isethionate, sodium cocoyl methyl isethionate and sodium lauroyl methyl isethionate, and combinations thereof. Suitable lactylate surfactants include alkali salts of acyl lactylate surfactants, such as sodium lauroyl lactylate. Such acyl lactylate surfactants may comprise one or more lactylate moieties, for example from one to three lactylate moieties. The acyl groups are preferably derived from fatty acids. Suitable acyl amino acid surfactants include alkali salts of acyl amino acid surfactants. Suitable acyl amino acid surfactants preferably comprise at least one amino acid residue and at least one fatty acid residue. The amino acid residues may be synthetic or biologically derived. Preferred acyl amino acid surfactants include one or more of an acyl sarcosinate, an acyl alaninate, an acyl glycinate and an acyl glutamate. Suitable acyl glycinates include cocoamphocarboxyglycinate, tallowamphocarboxygycinate, capryloamphocarboxyglycinate, oleoamphocarboxyglycinate, bis-2-hydroxyethyl tallow glycinate, lauryl amphoglycinate, tallow polyamphoglycinate, coco amphoglycinate, oleic polyamphoglycinate, / V-C10 / 12 fatty acid amidoethyl- / \ / -(2-hydroxyethyl)-glycinate, A / -C12 / 1 s-fatty acid amidoethyl-N-(2-hydroxyethyl)-glycinate, dihydroxyethyl tallow gycinate, and combinations thereof. Preferred acyl amino acid surfactants include sodium lauroyl sarcosinate, sodium cocoyl glycinate and sodium lauroyl glycinate, sodium oleoyl glycinate, sodium myristoyl glycinate, sodium cocoyl glutamate, sodium lauroyl glutamate, sodium oleoyl glutamate, sodium myristoyl sodium cocoyl alaninate and sodium lauroyl alaninate. Suitable taurate surfactants include compounds of the formula (VI): O R27 R29 R26—C---N---C---C---SO3X2 R31 R28 R30 (VI) wherein X2 is hydrogen, a metal ion or an optionally substituted ammonium ion, R26 represents an optionally substituted C3-C35 hydrocarbyl group, and each of R27, R28, R29, R30 and R31 independently represents hydrogen or a C1-C4 alkyl group. Preferred taurate surfactants include sodium lauroyl taurate, sodium cocoyl taurate, sodium oleoyl taurate, sodium myristoyl taurate, sodium N-methyl lauroyl taurate, sodium N-methyl cocoyl taurate, sodium N-methyl oleoyl taurate, sodium N-methyl myristoyl taurate, sodium N-methyl methyl lauroyl taurate, sodium N-methyl methyl cocoyl taurate, sodium N-methyl methyl oleoyl taurate and sodium N-methyl methyl myristoyl taurate. Suitable non-ionic surfactants (when present) may include alcohol alkoxylate surfactants (such as alcohol ethoxylates, alcohol propoxylates, and ethylene oxide / propylene oxide copolymer derived surfactants), aliphatic esters, aromatic esters, sugar esters, (especially sorbitan esters), glycerol esters including glycerol partial esters and glycerol triesters, fatty alcohols (such as cetearyl alcohol, lauryl alcohol, stearyl alcohol, behenyl alcohol), alkanolamides, glycolipids especially sophorolipids, rhamnolipids and alkyl glucosides. Suitable alkyl glucosides comprise one or more glucose moieties and an alkyl or alkenyl group. Where an alkyl glucoside comprises more than one glucose moieties, these are preferably present as an oligomer connected by glycosidic bonds. Suitable alkyl glucosides may comprise from 1 to 10 glucose moieties, preferably from 1 to 3. Suitable alkyl glucosides comprise an alkyl or alkenyl group having from 4 to 24 carbon atoms, for example decyl glucoside, lauryl glucoside, coco glucoside, capryl glucoside or caprylyl glucoside, and combinations thereof. A combination of capryl glucoside and caprylyl glucoside is preferred. Suitable cationic surfactants (when present) may include quaternary ammonium compounds (particularly trimethyl quaternary compounds), phosphonium quaternary ions and polymeric cationic surfactants (such as polyquaternium-7, polyquaternium-10, polyquaternium-11, guar hydroxypropyltrimonium chloride, and hydroxypropyl guar hydroxypropyltrimonium chloride). Suitable amphoteric surfactants (when present) may include those based on fatty nitrogen derivates and those based on betaines, as well as amine oxides. Suitable amphoteric or zwitterionic surfactants may be selected from betaines (for example alkyl betaines), alkylamidopropyl betaines (for example cocamidopropyl betaine), alkylamidopropyl hydroxy sultaines, amphoacetates (for example alkylamphoacetates), amphodiacetates (for example alkylamphodiacetates), alkyl propionates, alkylamphodipropionates, alkylamphopropionates, alkyliminodipropionates and alkyliminodiacetate. Cocamidopropyl betaine is preferred. Suitable amine oxides may include N-alkyl N,N-dimethyl amine oxides and alkylamido-N,N-dimethyl amine oxides (such as lauryldimethylamine oxide and cocamidopropyl dimethylamine oxide). Amphoteric or zwitterionic surfactants for use in compositions of the third aspect may include those which have an alkyl or alkenyl group of 7 to 22 carbon atoms, for example of the formula (VII): O R33 R32^C-NH(CH2)m2^N-X3-Y“ R34 (VII) where R32 is alkyl or alkenyl of 7 to 22 carbon atoms, R33 and R34 are each independently alkyl, hydroxyalkyl or carboxyalkyl of 1 to 6 carbon atoms, m2 is 2 to 4, n2 is 0 or 1, X3 is alkylene of 1 to 6 carbon atoms optionally substituted with hydroxyl, and Y is -CO2 or -SO3. Amphoteric or zwitterionic surfactants may include simple betaines of formula: r33 I + r32-n—ch2co2_ R34 and amido betaines of formula: O R33 -,2 11 1 + R32-C—NH(CH2)m2-N-CH2CO2- R34 where m2 is 2 or 3. In both formulae R32, R33 and R34 are as defined previously. R32 may, in particular, be a mixture of Ci 1 and C13 alkyl groups derived from coconut so that at least half, preferably at least three quarters, of the groups R32 has 9 to 13 carbon atoms. R33 and R34 are preferably methyl. Amphoteric or zwitterionic surfactants may include sulfobetaines of formula: r33 r32-n—(CH2)3SO3-r34 O R33 R32-C-NH(CH2)m2-N—(CH2)3SO3-R34 where m2 is 2 or 3, or variants of these in which -(CH2)3SO3_ is replaced by OH —CH2-CH-CH2SO3- where R32, R33 and R34 in these formulae are as defined previously. Non-biological amphoteric or zwitterionic surfactants may include amphoacetates and diamphoacetates. Amphoacetates generally conform to the following formula: R35CONHCH2CH2N—CH2CH2OH ch2coo_m+ Diamphoacetates may be of the formula: CH2COO“ M+ R35CONHCH2CH2N-CH2CH2O-CH2COO“M+ where R35 is an aliphatic group (such as an alkyl group) of 7 to 21 carbon atoms and M+ is a cation such as sodium, potassium, ammonium, or substituted ammonium. Suitable amphoacetate and amphodiacetate surfactants may include lauroamphoacetate (for example sodium lauroamphoacetate), lauroamphodiacetate (for example sodium lauroamphodiacetate), cocoamphoacetate (for example sodium cocoamphoacetate), cocoamphodiacetate (for example disodium cocoamphodiacetate), capryloamphodiacete (for example disodium capryloamphodiacete), and wheatgermamphodiacetate (for example disodium wheatgermamphodiacetate). Suitable betaine surfactants may include alkylamido betaine, alkyl betaine, C12 / 14 alkyldimethyl betaine, cocoamidopropylbetaine, tallow bis(hydroxyethyl) betaine, hexadecyldimethylbetaine, cocodimethylbetaine, alkyl amido propyl sulfo betaine, alkyl dimethyl amine betaine, coco amido propyl dimethyl betaine, alkyl amido propyl dimethyl amine betaine, cocamidopropyl betaine, lauryl betaine, laurylamidopropl betaine, cocamido betaine, lauryl amido betaine, alkyl amino betaine, alkyl amido betaine, coco betaine, lauryl betaine, diemethicone propyl PG-betaine, oleyl betaine, N-alkyldimethyl betaine, coco biguamide derivative, Ca amido betaine, C12 amido betaine, lauryl dimethyl betaine, alkylamide propyl betaine, amido betaine, alkyl betaine, cetyl betaine, oleamidopropyl betaine, isostearamidopropyl betaine, lauramidopropyl betaine, 2-alkyl-A / -carboxymethyl-A / -hydroxyethyl imidazolinium betaine, 2-alkyl-A / -carboxyethyl-A / -hydroxyethyl imidazolinium betaine, 2-alkyl- / \ / -sodium carboxymethyl-A / -carboxymethyl oxyethyl imidazolinium betaine, A / -alkyl acid amidopropyl-A / ,A / -dimethyl-A / -(3-sulfopropyl)-ammonium-betaine, A / -alkyl-A / ,A / -dimethyl-A / -(3-sulfopropyl)-ammonium-betaine, cocodimethyl betaine, apricotamidopropyl betaine, isostearamidopropyl betaine, myristamidopropyl betaine, palmitamidopropyl betaine, alkamidopropyl hydroxyl sultaine, cocamidopropyl hydroxyl sultaine, undecylenamidopropyl betaine, cocoamidosulfobetaine, alkyl amido betaine, C12 / 18 alkyl amido propyl dimethyl amine betaine, lauryldimethyl betaine, ricinol amidobetaine, tallow aminobetaine. The combination of surfactants (when present) used in the compositions of the third aspect may be free of alkoxylated compounds which could lead to the presence of 1,4-dioxane, or sulfates which can lead to skin and ocular irritation, or linear and / or branched alkylbenzene sulfonates which are derived from petrochemical sources. The composition may of the third aspect may comprise a soap, by which we mean a metal or alkanolamine salt of a fatty acid. Suitable soaps may comprise a fatty acid anion with from 4 to 36 carbon atoms and a cation selected from an alkanolamine, potassium and / or sodium. Examples of suitable soaps include potassium palm-kernelate, sodium palm-kernelate, potassium oleate and sodium stearate. Preferably, the composition of the third aspect may be a hair care or hair benefit composition. Suitably the composition enhances at least one property of the hair in use. Suitable hair care or hair benefit compositions include, for example, shampoo compositions, conditioning compositions, hairstyling compositions. The composition of the third aspect may be an anti-frizz composition. The anti-frizz composition may, for example, comprise from 0.1 to 15 wt% (preferably from 2 to 15 wt%) of an ester compound as defined herein and from 65 to 98 wt% of a carrier or solvent. The composition of the present invention may be a shampoo, for example a transparent shampoo or a pearlescent shampoo. The shampoo may, for example, comprise from 0.5 to 1.5 wt% of an ester compound as defined herein and from 60 to 98 wt% of a carrier or solvent (such as water). For example, the shampoo may comprise from 0.1 to 5 wt% of an ester compound as defined herein, from 0.01 to 2 wt% of a conditioning agent, from 3 to 25 wt% of surfactant, from 0.1 to 3 wt% of a pearlising agent, from 0.1 to 5 wt% of one or more further additional components and from 60 to 98 wt% (preferably from 60 to 96.69 wt%) of a carrier or solvent (such as water). Preferably, the shampoo may, for example, comprise from 0.5 to 1.5 wt% of an ester compound as defined herein, from 0.1 to 1 wt% of a conditioning agent, from 5 to 20 wt% of surfactant, from 0.5 to 2.5 wt% of a pearlising agent, from 0.1 to 5 wt% of one or more further additional components and from 60 to 98 wt% (preferably from 60 to 93.8 wt%) of a carrier or solvent (such as water). In one embodiment, the shampoo comprises from 0.1 to 5 wt% of an ester compound as defined herein, from 3 to 25 wt% of an anionic surfactant, from 0.1 to 5 wt% of a non-ionic surfactant and / or amphoteric or zwitterionic surfactant (preferably an alkyl glucoside and / or a betaine-based surfactant), and from 60 to 96.8 wt% of a carrier or solvent (such as water). In one embodiment, the shampoo comprises from 0.1 to 5 wt% of an ester compound as defined herein, from 0.01 to 2 wt% of hydroxy propyl guar hydroxypropyltrimonium chloride, from 3 to 25 wt% of sodium laureth sulfate and cocoamidopropyl betaine, from 0 to 5 wt% (or from 0.1 to 5 wt%) of caprylyl / capryl glucoside, and from 60 to 96.89 wt% of a carrier or solvent (such as water). The composition of the third aspect may be a conditioner, for example a leave in or rinse out conditioner, preferably a leave in conditioner. The conditioner may, for example, comprise from 0.1 to 2 wt% of an ester compound as defined herein, from 0.5 to 5 wt% of a conditioning agent, from 0.1 to 5 wt% of one or more further additional components and from 60 to 98 wt% of a carrier or solvent. The composition of the third aspect may be a hairstyling composition. Suitable hairstyling compositions may include hairsprays (aerosol and non-aerosol), gels (such as colouring gel and spray gels), lotions (such as colouring lotions), spritz creams, putty, pastes, clays, waxes, pomadee, mousses (such as pump mousses, aerosol mousses and hair colouring aerosol mousses), gel-to-mousses and powders. The composition of the third aspect may be a hair mousse. The hair mousse may, for example, comprise from 0.1 to 2 wt% of an ester compound as defined herein, from 0.1 to 2 wt% of surfactant, from 0.5 to 5 wt% of a conditioning agent, from 0.1 to 5 wt% of an additional moisturising agent, plasticiser and / or texturising agent (such as glycerin), from 0.1 to 5 wt% of one or more further additional components and from 70 to 98 wt% of a carrier or solvent (such as water). The composition of the third aspect may be a hairspray composition. The composition of the third aspect may be in the form of an aerosol composition. When the composition is in the form of an aerosol composition, the composition may comprise a propellant as described herein. An aerosol composition may, for example, comprise further additional components selected from anti-corrosion agents, conditioning agents, additional shine agents, thermal protection agents, co-styling polymers, fragrances, neutralisers for styling polymers, rheology modifiers, pH adjustment agents, plasticisers, additional moisturising agents, carriers / solvents, slip agents, texturising agents, UV absorbers, wetting agents, emulsifiers, and other active ingredients. The carrier / solvent may comprise water or an ethanol / water mix. The composition of the third aspect may be in the form of a gel composition. A gel composition may, for example, comprise further additional components selected from anti-corrosion agents, anti-dandruff agents, chelating agents, texturising agents, conditioning agents, anti-static agents, additional shine agents, thermal protection agents, texture modifying agents, co-styling polymers, other active ingredients, fragrance, fragrance solubilising agents, hair colouring agents, neutralising agents for styling polymers, rheology modifiers, pH adjusters, plasticisers, additional moisturising agents, wetting agents, preservatives, product colouring agents, slip agents, carriers / solvents, UV absorbing agents, rheology modifiers, and viscosifiers. The composition of the third aspect may be used one or more times as a hair care or hair treatment composition. The composition may be in the form of shampoo, conditioner or hair styling product, for example a serum, wax, mousse, gel or spray or any other hair treatment form that could be used to provide general hair care benefits. Compositions which perform multiple functions, for example combined shampoo and conditioning compositions are also within the scope of the invention. The composition of the third aspect may, in use thereof, be contacted with keratinous material (especially hair) which is wet or dry. Suitably the composition of the third aspect may be applied to the keratinous material (especially hair) and spread across the surface of the keratinous material (especially hair). Preferably when the keratinous material is hair the composition may be rubbed into the hair in the manner of a shampoo and / or it may be combed through the hair. The composition of the third aspect may be left on the keratinous material (especially hair) or it may be removed from the keratinous material (especially hair). Suitably the composition may be rinsed using warm water. In some embodiments the composition of the third aspect may be contacted with the keratinous material (especially hair), spread throughout and then immediately removed. Suitably the composition of the third aspect may be removed from the keratinous material (especially hair) by rinsing, preferably by using water. In some embodiments the composition of the third aspect may be washed from the keratinous material (especially hair) by washing with a detergent composition. In some embodiments the composition of the third aspect may be mechanically removed from the keratinous material (especially hair), for example by brushing. In some embodiments in which the keratinous material is hair, the composition of the third aspect may be applied to the hair, spread throughout and rubbed into the hair, and then rinsed with water, in the manner of a shampoo. In some embodiments in which the keratinous material is hair, the composition of the third aspect may be applied to the hair, spread throughout the hair (optionally with combing), left on the hair for a short period and then rinsed from the hair with water, in the manner of a conditioner. In some embodiments in which the keratinous material is hair, the composition of the third aspect may be contacted with the hair and left on the hair in the manner of a styling product. The composition may be sprayed throughout the hair, rubbed throughout the hair, combed throughout the hair or otherwise spread through the hair in a manner known to those skilled in the art. In embodiments in which the composition is left on the hair, it suitably remains on the hair until the hair is next washed, although some of the composition may be brushed out or rubbed away during normal activity. In the method and use of the first and second aspects, and in use of the composition of the third aspect, the ester compound or composition is suitably contacted with the keratinous material (especially hair) at ambient temperature. In some embodiments the ester compound or composition may be contacted with the keratinous material (especially hair) at a temperature greater than the ambient temperature. In some embodiments the ester compound or composition may be contacted with the keratinous material (especially hair) and the keratinous material (especially hair) carrying the ester compound or composition may then be heated and / or manipulated and / or dried. Thus the hair may be dried using a hairdryer or straightened after the ester compound or composition is applied. The composition of the third aspect may be applied to the keratinous material (especially hair) when it is heated. Such a heating step may involve commonly used heating techniques such as blow drying, or using tongs, straighteners or hoods etc. The composition of the third aspect may be used on a regular basis, for example every time the keratinous material (especially hair) is washed. Alternatively the composition may be used periodically on a less frequent basis, for example, every week or every month. The fourth aspect of the present invention provides a packaged keratinous material treatment product. The product comprises packaging, a composition housed in the packaging and instructions for use of the composition in the treatment of a suitable keratinous material, wherein the composition comprises one or more ester compounds, Suitable features of the composition, the ester compound and the keratinous material are as described herein in relation to the first, second and third aspects. The keratinous material may, for example, be hair, nails, horns, claws or hooves. Preferably, the keratinous material is hair. Preferably, the packaged keratinous material treatment product is a packaged hair treatment product, such as a packaged hair care product. The packaged keratinous material treatment product may comprise any suitable packaging. Examples of suitable packaging include bottles, tubs, sachets, pouches, films, and boxes. The form of the packaging may depend on the form of the composition comprising the ester compound. When the composition is a liquid composition, the packaging may be selected from a bottle, tub, sachet, or pouch. When the composition is a solid composition, the packaging may be selected from a sachet, pouch, film or box. Examples The invention will now be further described with reference to the following non-limiting examples. Example 1 - general method for synthesis of ester compounds The cyclic anhydride reactant was combined with the polyol reactant(s). Tin(ll) ethylhexanoate (0.5 wt% relative to the total weight of reactants) was added. The reaction mass was heated at 160°C for 6 hours. The resulting ester compound was decanted from the reaction flask, and no further purification was carried out. Ester compounds 1 to 9 were prepared according to Example 1, using the reactants and reaction stoichiometries as set out in Table 1. Table 1 Ester compound Cyclic anhydride reactant Polyol reactant 1 Polyol reactant 2 (when present) Molar ratio of reactants 1 Octadecenyl succinic anhydride N- Methyldiethanolamine 1 : 1 2 (2-Dodecen-1-yl)succinic anhydride Castor oil 1 : 1 3 Nonenyl succinic anhydride PEG 200 1 : 1 4 (2-Dodecen-1-yl)succinic anhydride Tri methylolpropane 1 : 1 5 (2-Dodecen-1-yl)succinic anhydride Sorbitol 1,6-Hexanediol 1 : 0.25 : 0.75 6 (2-Dodecen-1-yl)succinic anhydride N- methyldiethanolamine 1 : 1 7 Nonenyl succinic anhydride Castor oil 1 : 1 8 (2-Dodecen-1-yl)succinic anhydride N-butyldiethanolamine PEG 200 1 : 0.5 : 0.5 9 (2-Dodecen-1-yl)succinic anhydride N-butyldiethanolamine Neopentyl glycol 1 : 0.5 : 0.5 Table 2 - abbreviations and chemical names PEG Poly(ethylene glycol) Example 2 - evaluation of ester compound anti frizz properties The ester compounds of Table 1 were tested for their ability to reduce frizz from hair by using the test as follows: Brazilian Curly hair tresses were pre-washed with a solution in water of 10% SLES-2 (sodium lauryl ethoxy sulfate having an average of 2 moles of ethylene oxide) and then blow dried with a RUSK ® PRO Engineering Speed Titanium Hair Dryer set at high temperature. The dried hair tresses were hung overnight in a humidity chamber at 80°F (circa 26.7°C) and 80% relative humidity (RH), allowing hair to frizz to 100%. Tresses were then removed from the humidity chamber, coded and photos were taken for each tress. These photos were used to calculate the initial total area of each hair tress using an image analysis software (Image Pro Plus ©version 7.0; Media Cybernetics, Inc). The hair tresses were wet down under running water for approximately 10 seconds and excess water was removed by patting down the hair tresses on a towel. Ester compound formulations consisting of 1 wt% ester compound, 10 wt% of isopropyl alcohol, 0.3 wt% of C9-C11 alcohol ethoxylate with an average degree of ethoxylation of 8, and 88.7 wt% water were prepared. 1mL of the ester compound formulation was hand-applied to the tress and the tresses were hung again in the humidity chamber operated at the same initial temperature and humidity conditions (80°F I 80% RH). Hair tresses were removed from the humidity chamber after 24 hours and photos were taken. The total area of the treated hair tress was calculated using the Image Pro Plus © software. The degree of frizz reduction was calculated as the percent difference between the initial tress area and treated tress area. The process was performed in duplicate for each test formulation and the average percent difference was recorded. The results are shown in Table 3. Table 3 Ester compound Cyclic anhydride reactant Polyol reactant Molar ratio of reactants % Frizz reduction of ester compound formulation 1 Octadecenyl succinic anhydride N- Methyldiethanolamine 1 : 1 98 2 (2-Dodecen-1-yl)succinic anhydride Castor oil 1 : 1 97 The post-treated hair tresses were soft and smooth to the touch, and an undesirable “plasticized” or “crispy” feel was absent. Example 3 - evaluation of anti frizz properties 1% w / w test samples of the ester compound with 0.2 wt% of a solution of 35 wt% sodium lauroamphoacetate and 5 wt% ethanol were prepared in spray bottles. Brazilian Curly Type 4 Hair Tresses (1.5 cm wide, 3 g) were washed twice with 1 mL of 10 wt% Sodium Laureth sulfate solution. The hair was then allowed to dry for 2 hours at ambient temperature before being placed in a humidity chamber at 80% RH (Relative Humidity) overnight at ambient temperature 20-22°C to fully ‘frizz’ the hair tress. Photos were taken of the frizzed hair tresses, and the hair area was calculated via image analysis to act as control to calculate the % frizz reduction (Tc: “control untreated tress”). 1.0 g of test solution was sprayed onto the hair tress and then massaged from root to tip to fully coat the hair and then combed twice with wide tooth comb. The tress was then placed in the humidity cabinet at 80%RH at ambient temperature 20-22°C for 6 hours, with photos taken initially (Ti: “initial treated tress”) and then after 6 hours (Teh: “treated tress after 6h") to calculate the tress increase in area, via image analysis. % initial frizz reduction was calculated compared to the control swatch with the following formula: % initial frizz reduction = 100 — (kx10°) Retention of frizz reduction after 6 hours was calculated as follows: % antifrizz retention after 6 hours = 7c Teh Tc-Tt x 100 For an ester compound to be classed as a pass the tress has to show an initial reduction in % area of >40% and maintain at least >50% of this reduction after 6 hours at 80% RH ambient temperature (20-22°C). The results are shown in Table 4. Table 4 - Antifrizz performance of ester compounds Ester compound % Initial frizz reduction % Antifrizz retention after 6 hours Antifrizz performance 1 54 98 Pass 2 51 58 Pass 4 43 95 Pass 6 58 100 Pass 7 55 76 Pass 9 56 100 Pass Example 4 - Evaluation of dry combing performance Aqueous:ethanol (95:5) test emulsions were prepared with 0.2% w / w of a solution of 35 wt% sodium lauroamphoacetate and 1% w / w of the ester compound. Double bleached Caucasian hair (5 g, 10 inch) was washed 3 times with a 10 wt% sodium laureth sulfate solution to remove any previous treatments. Hair was dried for 2 minutes with a hair dryer at heat setting 2 and speed 2. Hair was combed twice with a wide tooth comb to remove any knots and tangles before testing. Hair was combed on a Texture Analyser with an A500 narrow tooth comb for 20 cycles and combing force was determined for the untreated hair. The swatch was then treated by spraying 1.0 g of the ester compound solution, across the whole of the hair and then massaging to give even coating of the hair fibres. Hair was dried for 1 minute, with hair dryer at heat setting 2 and speed 2. Hair was combed twice with a wide tooth comb to remove any knots and tangles before testing. Hair was combed on Texture Analyser with an A500 narrow tooth comb for 20 cycles and combing force was determined for the treated hair. The % reduction in combing force between treated and untreated swatch was calculated. The results are shown in Table 5. Table 5 - Dry combing performance of ester compounds Ester compound % reduction in combing force 2 26.6 5 30.4 8 25.1 9 20.6 Example 5 - Formulations A base formulation was prepared according to Table 6. Table 6 - Base formulation INCI wt% active Water 85.17 Hydroxypropyl Guar Hydroxypropyltrimonium Chloride 0.25 Citric Acid (50 wt%) q.s to pH 4.0 Sodium Laureth Sulfate 9.74 Cocamidopropyl Betaine 2.34 Sodium Benzoate 0.50 Citric Acid (50 wt%) q.s to pH 5.0 Impurities To 100 Separately, an ester compound was combined in a 1:1 weight ratio with an emulsifier which was a 70 wt% Capryl / Caprylyl Glucoside solution (GLUCO). The emulsion was mixed until a clear solution was obtained. The emulsion and NaCI were added to the base formulation, and mixed until uniform to provide the shampoo formulation of Table 7. Table 7 -Shampoo Formulation Ingredient Wt% Base formulation To 100 Ester compound 1 Emulsifier 1 NaCI 2.5 Shampoo formulations according to Table 8 were prepared following the preparation method from Example 5. pH and viscosity of the shampoo formulations were recorded. Viscosity was determined with a Brookfield DVI-Prime set to 20 rpm at 20 °C. Table 8 Ester compound Emulsifier pH Viscosity 3 GLUCO 5.1 8060 cps 4 GLUCO 5.1 1120 cps GLUCO: Caprylyl / Capryl Glucoside Unless otherwise stated herein, the reference to “liquid”, “gel” and “solid” refer to a state at 25 °C and standard pressure (101,325 Pa). Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. All of the features disclosed in this specification (including any accompanying claims, and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. 5 The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. 10

Claims

1. A method of treating a keratinous material growing on a body, the method comprising contacting the keratinous material with an ester compound, wherein the ester compound is the reaction product of reactants comprising one or more first reactants and one or more second reactants, wherein the or each first reactant is a cyclic anhydride and the or each second reactant is a polyol.

2. A use of an ester compound to treat a keratinous material growing on a body, wherein the ester compound is the reaction product of reactants comprising one or more first reactants and one or more second reactants, wherein the or each first reactant is a cyclic anhydride and the or each second reactant is a polyol.

3. A composition for treating a keratinous material growing on a body, wherein the composition comprises one or more ester compounds, and wherein the or each ester compound is the reaction product of reactants comprising one or more first reactants and one or more second reactants, wherein the or each first reactant is a cyclic anhydride and the or each second reactant is a polyol.

4. The method, use or composition according to any preceding claim, wherein the ester compound is a polymer.

5. The method, use or composition according to claim 4, wherein the polymer comprises at least 4 monomer units.

6. The method, use or composition according to any preceding claim, wherein the or each cyclic anhydride is one or more of an anhydride of formula (I), of formula (II) or of formula (III):wherein in formula (I) R1 and R2 are each independently selected from hydrogen, an alkyl group and an alkenyl group, or R1 and R2 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group;in formula (II) R3 and R4 are each independently selected from hydrogen, an alkyl group and an alkenyl group, or R3 and R4 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group; andin formula (III) X is CR9R10, O, S, or NR11; R5, R6, R7, R8, R9, R10, and R11 are each independently selected from hydrogen, an alkyl group and an alkenyl group, and / or any of R5, R6, R7, R8, R9, R10, and R11 together with the atoms to which they are attached represent an optionally substituted cyclic group.

7. The method, use or composition according to claim 6, wherein the or each first reactant is a cyclic anhydride selected from one or more of succinic anhydride, maleic anhydride, glutaric anhydride, a Ce-30 alkenyl succinic anhydride such as C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, octadecyl succinic anhydride, or octyl succinic anhydride, a branched alkenyl succinic anhydride such as tetrapropenyl succinic anhydride or polyisobutenyl succinic anhydride, phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 1,2-naphthalic anhydride, 2,3-naphthalic anhydride, 1,8-naphthalic anhydride and homophthalic anhydride.

8. The method, use or composition according to claim 6 or 7, wherein the or each first reactant is a cyclic anhydride selected from one or more of succinic anhydride, maleic anhydride, C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-cyclohexanedicarboxylic anhydride and 1,8-naphthalic anhydride.

9. The method, use or composition according to any preceding claim, wherein the or each second reactant is a polyol having from 2 to 10, preferably from 2 to 6, more preferably 2 or 3, hydroxy groups.

10. The method, use or composition according to claim 9, wherein the or each polyol is selected from one or more polyol of the formula (IV), one or more of an alkoxylated polyol of formula (IV), one or more nitrogen containing polyol, and one or more polyol formed by reaction of a hydroxy substituted cyclic ester or cyclic carbonate with a suitable primary or secondary amine compound, wherein the polyol of formula (IV) is of the formula H-(OR17)P-OH, whereineach R17 is independently an optionally substituted hydrocarbylene group and p is an integer of at least 1.

11. The method, use or composition according to claim 9 or 10, wherein the or each second reactant is a polyol independently selected from castor oil, 1,6-hexanediol, sorbitol, neopentyl glycol and a polyalkylene glycol (such as PEG 200).

12. The method, use or composition according to any preceding claim, wherein the ester compound hasa number average molecular weight of from 1,000 to 150,000 Daltons, preferably from 1,000 to 15,000 Daltons (for example from 2,000 to 7,000 Daltons).

13. The method, use or composition according to any preceding claim, wherein the ester compound is substantially free of silicon atoms.

14. The method, use or composition according to any preceding claim, wherein the keratinous material is hair.

15. The method, use or composition according to claim 14, wherein the hair is human hair.

16. The method, use or composition according to claim 14, wherein the hair is animal hair.

17. The method, use or composition according to any preceding claim, which provides abeneficial effect to or enhances a property of the keratinous material.

18. The method, use or composition according to claim 17, wherein the property is a conditioning effect.

19. The method, use or composition according to any preceding claim, wherein the property of the keratinous material that is changed, beneficially affected or enhanced may be one or more of the following:• reduction in frizziness• shine• gloss• softness• silkiness• moisturise level• thermal durability• protection against damage• strength• combability• smoothness• drying time20. The composition according to any of claims 3 to 19, which is an anti-frizz composition.

21. The composition according to any of claims 3 to 20, which is a shampoo or a bodywash,preferably a shampoo.

22. The composition according to claim 21, which is a leave in shampoo.

23. The composition according to any of claims 3 to 20, which is a conditioner, preferably aleave in conditioner.

24. The composition according to any of claims 3 to 23, wherein the composition is an animal (for example pet) care composition.

25. A packaged keratinous material treatment product comprising packaging, a composition housed in the packaging and instructions for use of the composition in the treatment of a suitable keratinous material growing on a body, wherein the composition comprises one or more ester compounds, and wherein the or each ester compound is the reaction product of reactants comprising one or more first reactants and one or more second reactants, wherein the or each first reactant is a cyclic anhydride and the or each second reactant is a polyol.A