Sealant composition

Abstract

A sealant composition comprises a resin; an oil; and a solvent e.g. acetone. The resin is preferably a naturally occurring resin, in particular a resin extracted from trees of the genus Pinus or Arauc

Description

The present invention relates to a sealant composition. The present invention also relates to a method for forming the sealant composition and the use of the composition. Sealant compositions have been known and used for many years. Generally, sealant compositions comprise a filler and an elastomeric material, to provide the required flexibility. Sealant compositions may be setting, that is they set or cure to become more solid and less flexible over time and form a cement-like material, or non-setting, that is remain flexible. Sealant compositions may have a wide range of physical and chemical properties, ranging from higher-strength, adhesive-derived sealants and coatings to low-strength putties, waxes, and caulks. Putties and caulks serve only one function, that is to take up space and fill voids. Sealant compositions are used in a wide range of applications where the passage of fluids, especially liquids, through an opening in a structure is to be prevented. One particular use for sealant compositions is to provide a seal between components of an apparatus or machine, in particular to retain fluid within the apparatus or machine and / or to prevent fluid from entering components of the apparatus or machine. Sealant compositions are used extensively in such industries as the automotive industry, for example to provide a seal between components of an internal combustion engine, a transmission assembly or other components of the drive train of an automobile. Sealant compositions may be used in combination with gaskets to provide a fluid-tight seal. Gaskets are also used widely throughout a range of industries, including the automotive industry. Aibada, N., et al., ‘Review on Various Gaskets Based on the Materials, their Characteristics and Applications’, International Journal on Textile Engineering and Processes, Vol. 3, Issue 1, January 2017, pages 12 to 18, provides a review of different gaskets and gasket materials. There is a need to provide an improved sealant composition, which may be used to provide a fluid-tight seal between components. It would be advantageous if the sealant composition could be used either in combination with a gasket or alone to provide the seal. US 4,514,529 discloses an oil-resistant, low modulus silicone sealant composition. The composition comprises a silanol-terminated diorganosiloxane base polymer, a trimethylsilyl-terminated diorganopolysiloxane, a tin catalyst, an oxime crosslinking agent, and a low moisture filler, such as calcium carbonate. The composition is described as being useful as a gasket sealant. US 2003 / 0162928 discloses a one-pack, room temperature-curable sealant composition. The composition is described as being useful in the automotive industry. The composition comprises an organopolysiloxane terminated with hydroxyl groups, a crosslinking agent, zinc carbonate and / or zinc oxide, tabular alumina and a silane coupling agent. The composition is said to possess excellent adhesive properties and a high chemical resistance. The composition is of particular in sealing components formed from magnesium alloys. CN 117586746 A concerns a gasket-free silicone sealant and a method for its preparation. The sealant comprises a terminated silicone rubber, a fatty acid, a powdered filler comprising modified calcium carbonate, fumed silica, a flame retardant and a crosslinking agent. More recently, WO 2024 / 053644 discloses a sealant resin composition. The composition comprises a 1-butene / ethylene copolymer and a propylene polymer having a specific Shore D hardness and a specific melt flow rate. The composition is said to have good heat sealing properties and a high resistance to whitening during stretching. Still more recently, US 2024 / 0141099 discloses a sealant composition. The composition comprises a pre-polymer comprising a polymeric unit having the general formula (-A-B-)n, where A represents a substituted or unsubstituted ester, B represents a substituted or unsubstituted acid ester comprising a least two acid ester functional groups, and n is an integer greater than 1. The composition is described as having improved adhesive and sealant properties. There is a need for an improved sealant composition. It would be advantageous if the sealant composition is compatible with a wide range of metals and metal alloys, as well as being compatible with materials used to form gaskets. It would also be advantageous if the sealant composition could be formed from readily available materials in a simple method. Further, it would be advantageous if the sealant composition could be formed from components that are environmentally friendly and providing little or no hazard to persons coming into contact with the composition during or after use. According to the present invention, there is provided a sealant composition comprising: a resin; an oil; and a solvent. The composition comprises a resin. The resin functions as a tackifier, providing the composition with tackiness. The tackiness of the sealant composition may be controlled by varying the amount of resin present in the composition. Preferably, the resin comprises one or more naturally occurring resins or derivatives thereof. More preferably the resin comprises a resin extracted from a resinous plant. In one preferred embodiment, the composition comprises a resin extracted from one or more parts of a tree. In one preferred embodiment, the resin comprises a resin extracted from the stumps of trees. Any suitable tree resin may be employed. In one preferred embodiment, the resin comprises a resin extracted from trees of the genus Pinus or Araucaria. In one preferred embodiment, the resin used in the composition of the present invention comprises a resin extracted from trees of the species Araucaria angustifolia (common name Parana pine, Brazilian pine or candelabra tree). In another preferred embodiment, the resin used in the composition of the present invention comprises a resin extracted from trees of the genus Pinus, that is pine trees. Resin extracted from pine stumps is particularly suitable for use in the sealant composition of the present invention. The sealant composition may comprise one or more resins. As noted above, preferably the composition comprises one or more resins that are naturally occurring, more preferably extracted from one or more resinous plants, such as the aforementioned species of trees. In a preferred embodiment, the resin comprises a rosin. Rosin (also referred to as colophony), as defined by the European Chemicals Agency (ECHA) as a complex combination derived from wood, especially pine wood, composed primarily of resin acids and modified resin acids such as dimers and decarboxylated resin acids. Rosin may include rosin stabilized by catalytic disproportionation. Rosin is a solid form of resin extracted from plants of the genus Pinus and other plants. Rosin is produced by heating fresh liquid resin to vaporise the volatile terpene components and recovering the remaining solid. The primary components of rosin resins are a range of resin acids, the major acid being abietic acid: As noted above, the resin used in the composition of the present invention is most preferably a naturally occurring resin. However, the resin may be a derivative of a naturally occurring resin. For example, the resin may be treated with a carboxylic acid to produce an ester. Suitable carboxylic acids include C2 to Ce carboxylic acids. Resins treated with C4 carboxylic acids may be used in a number of embodiments. The carboxylic acids may be mono-carboxylic acids or di-carboxylic acids. In many embodiments the resin is treated with a di-carboxylic acid. In one preferred embodiment, the resin is a derivative of a naturally occurring resin prepared by treating the naturally occurring resin with butenedioic acid or one of its isomers, in particular fumaric acid or maleic acid. Suitable resins for use in the present invention are available commercially and are known in the art. One preferred resin for use in the composition of the present invention is the Carbofen® resin available commercially from PolyTrade. Carbofen® resin is derived from trees of the species Araucaria angustifolia (common name Parana pine, Brazilian pine or candelabra tree). An alternative commercial resin product that has been available is Vinsol® resin, available from Darwin Chemical Company. A further alternative resin product that may be employed in the composition of the present invention is Respin, available from A.F. Suter and Co. Ltd. As noted above, the resin functions in the composition as a tackifier, providing tackiness to the composition. The degree of tackiness of the composition may be adjusted by varying the amount of resin present in the composition. The resin may be present in the composition in an amount to provide the required sealant properties of the composition, including tackiness. The resin may be present in an amount of from 5% by weight, preferably from 10% by weight, more preferably from 15% by weight, still more preferably from 20% by weight, more preferably still from 25% by weight. For a composition that is to be applied by spreading, the resin may be present in higher amounts, for example an amount of from 30% by weight, more especially from 35% by weight, still more especially from 40% by weight. The resin may be present in an amount of up to 85% by weight, preferably up to 80% by weight, more preferably up to 75% by weight, still more preferably up to 70% by weight, more preferably still up to 65% by weight, especially up to 60% by weight, more especially up to 55% by weight, still more especially up to 50% by weight, more preferably up to 45% by weight. For a composition that is to be applied by spraying, the resin may be present in a lower amount. For example, the resin may be present in an amount of up to 40% by weight, preferably up to 35% by weight, more preferably up to 32% by weight, still more preferably up to 30% by weight. The resin may be present in an amount of from 5 to 80% by weight, preferably from 10 to 75% by weight, more preferably from 15 to 70% by weight, still more preferably from 20 to 65% by weight, more preferably still from 25 to 60% by weight. In a composition to be applied by spreading, the resin may be present in an amount of from 30 to 55% by weight, more especially from 35 to 50% by weight, still more especially from 40 to 45% by weight. For a composition that is to be applied by way of spraying, the resin may be present in an amount of from 20 to 40% by weight, preferably from 25 to 35% by weight, more preferably from 26 to 32% by weight, especially from 27 to 30% by weight. The sealant composition of the present invention further comprises an oil. The oil is present to provide the composition with mobility, allowing it to be applied to a surface, for example by spreading, painting or spraying. In addition, the oil reduces the rate at which the solvent in the composition evaporates, preventing the composition from thickening excessively and solidifying. The composition may comprise any suitable oil or mixture of oils. Suitable oils include mineral oils, in particular an oil obtained by the refining of crude oil. The mineral oil may be a petroleum base oil, for example one or more oils falling within Groups I, II, III and V of the American Petroleum Institute (API) API 1509, Annex E. Alternatively, the mineral oil may be a synthetic base oil falling within Group IV of API 1509, Annex E. The composition may employ one or more fully formulated oils, such as motor oils formulated for use in internal combustion engines, including semi-synthetic and fully synthetic motor oils. More preferably, the sealant composition of the present invention comprises a naturally occurring oil, in particular an oil obtained from plants. Suitable naturally occurring oils include edible and non-edible oils. Examples of naturally occurring oils that may be used in the composition of the present invention include castor oil, coconut oil (copra oil), colza oil, corn oil, cottonseed oil, false flax oil, hemp oil, mustard oil, palm oil, peanut oil, radish oil, rapeseed oil, ramtil oil, rice bran oil, safflower oil, salicornia oil, soybean oil, sunflower oil, tigernut oil, tung oil, copaiba oil, jatropha oil, jojoba oil, milk bush, nahor oil, paradise oil, petroleum nut oil, pongamia oil (also known as honge oil). Preferred oils include castor oil, coconut oil, corn oil, rapeseed oil, colza oil, sunflower oil, palm oil and soybean oil. Castor oil is a particularly preferred oil for use in the composition of the present invention. Suitable oils for use in the present invention are available commercially and are known in the art. As noted above, the oil functions in the composition to render the composition mobile, that is able to be applied to a surface by spreading or spraying. The oil also reduces the rate of evaporation of the solvent. The degree of mobility of the composition and the rate of evaporation of the solvent may be adjusted by varying the amount of oil present in the composition. The oil may be present in the composition in an amount to provide the required sealant properties of the composition, for example to provide the required mobility of the composition and to reduce evaporation of the solvent and solidification of the composition after application. The oil may be present in an amount of from 2% by weight, preferably from 3% by weight, more preferably from 5% by weight, still more preferably from 6% by weight, more preferably still from 8% by weight. For a composition that is to be applied by spreading, the oil may be present in higher amounts, for example an amount of from 10% by weight, more especially from 12% by weight, still more especially from 14% by weight. The oil may be present in an amount of up to 30% by weight, preferably up to 25% by weight, more preferably up to 22% by weight, still more preferably up to 20% by weight, more preferably still up to 18% by weight, especially up to 17% by weight, more especially up to 16% by weight, still more especially up to 15% by weight. For a composition that is to be applied by spraying, the oil may be present in a lower amount. For example, the oil may be present in an amount of up to 14% by weight, preferably up to 12% by weight, more preferably up to 10% by weight. The oil may be present in an amount of from 2 to 30% by weight, more preferably from 4 to 28% by weight, still more preferably from 5 to 25% by weight, more preferably still from 6 to 22% by weight, especially from 8 to 20% by weight. In a composition to be applied by spreading, the oil may be present in an amount of from 5 to 25% by weight, more especially from 10 to 20% by weight, still more especially from 12 to 18% by weight. For a composition that is to be applied by way of spraying, the resin may be present in an amount of from 5 to 15% by weight, preferably from 6 to 14% by weight, more preferably from 7 to 13% by weight, especially from 8 to 12% by weight. The sealant composition of the present invention further comprises a solvent. The solvent may be any solvent or combination of solvents that is able to dissolve the resin and is miscible with the oil. The solvent may consist of a single solvent or a mixture of two or more solvents. The solvent may be aromatic, aliphatic or alicyclic. Suitable solvents include polar solvents, such as aldehydes, carboxylic acids, esters, ethers, ketones, terpenes and alcohols. Preferred aldehydes are C2 to Ce aldehydes, more preferably C2 to C4 aldehydes. Preferred carboxylic acids are C2 to Ce carboxylic acids, more preferably C2 to C4 carboxylic acids, especially acetic acid. Preferred esters are C3 to Cs esters, more preferably C3 to Ce esters. Preferred ethers are C2 to Ce ethers, more preferably C2 to C4 ethers. Preferred ketones are C3 to Cs ketones, more preferably C3 to Ce ketones. Preferred terpenes are alpha- and beta-pinene, carene, camphene, limonene, and terpinolene, preferably a mixture thereof provided as turpentine. Preferred alcohols are C2 to Ce alcohols, more preferably C2 to C4 alcohols. In one preferred embodiment, in which the resin comprises rosin, the preferred solvents are alcohols, ketones, and terpenes, more preferably C2 to C4 alcohols, such as ethanol and propanol, including n-propanol and iso-propanol; C3 to Cs ketones, such as acetone; and terpenes, in particular turpentine. Ketones are one preferred group of solvents, with acetone being a particularly preferred solvent. The solvent may be present in the composition in an amount to provide the required sealant properties of the composition. For example, the amount of solvent present may be determined by manner in which the sealant composition is to be applied. The solvent may be present in the composition in an amount to provide the required sealant properties of the composition, for example depending upon the manner in which the composition is to be applied to a surface. The solvent may be present in an amount of from 5% by weight, preferably from 10% by weight, more preferably from 15% by weight, still more preferably from 20% by weight, more preferably still from 25% by weight, especially from 30% by weight, more especially from 35% by weight. For a composition that is to be applied by spraying, the solvent may be present in higher amounts, for example an amount of from 40% by weight, more especially from 45% by weight, still more especially from 50% by weight, preferably from 55% by weight. The solvent may be present in an amount of up to 90% by weight, preferably up to 85% by weight, more preferably up to 80% by weight, still more preferably up to 75% by weight, more preferably still up to 70% by weight, especially up to 65% by weight. For a composition that is to be applied by spreading, the solvent may be present in lower amounts, for example up to 60% be weight, more especially up to 55% by weight, still more especially up to 50% by weight, more preferably up to 45% by weight. The solvent may be present in an amount of from 5 to 90% by weight, preferably from 10 to 85% by weight, more preferably from 15 to 80% by weight, still more preferably from 20 to 75% by weight, more preferably still from 25 to 70% by weight. For a composition that is to be applied by way of spraying, the solvent may be present in an amount of from 40 to 75% by weight, preferably from 45 to 70% by weight, more preferably from 50 to 70% by weight, especially from 55 to 65% by weight. In a composition to be applied by spreading, the solvent may be present in a lower amount, for example an amount of from 30 to 55% by weight, more especially from 35 to 50% by weight, still more especially from 40 to 45% by weight. In one embodiment, the sealant composition is to be applied by spreading, for example by way of a brush or spreader. In the case of a composition to be applied by spreading, the amount of solvent present is lower. The solvent may be present in an amount of from 5 to 80% by weight, preferably from 10 to 75% by weight, more preferably from 15 to 70% by weight, still more preferably from 20 to 65% by weight, more preferably still from 25 to 60% by weight, especially from 30 to 55% by weight, more especially from 35 to 50% by weight, still more especially from 40 to 45% by weight. In an alternative embodiment, the sealant composition is to be applied by spraying. In the case of a sprayable composition, the amount of solvent employed is higher, in order to render the composition able to be propelled through a nozzle to form a spray. The solvent may be present in an amount of from 5 to 90% by weight, preferably from 10 to 85% by weight, more preferably from 15 to 80% by weight, still more preferably from 20 to 75% by weight, more preferably still from 25 to 70% by weight, especially from 30 to 65% by weight, more especially from 35 to 60% by weight, still more especially from 40 to 55% by weight. The resin, solvent and oil may be present in the composition in the amounts described hereinbefore. As described, the relative amounts of the components varies according to the type of composition, in particular whether the composition is to be applied by spreading or by spraying. The weight ratio of the resin to the solvent in the composition may be from 6:1 to 1:6. The weight ratio of the resin to the oil in the composition may be from 5:1 to 1:5. The weight ratio of the solvent to the oil in the composition may be from 10:1 to 1:5. In embodiments where the sealant composition is for applying by spreading, the weight ratio of the resin to the solvent may be from 4:1 to 1:4, preferably from 3.5:1 to 1:3.5, more preferably from 3:1 to 1:3, still more preferably from 2.5:1 to 1:2.5, more preferably still from 2:1 to 1:2, especially from 1.5:1 to 1:1.5. A weight ratio of resin and solvent of about 1:1 is preferred for many embodiments. The weight ratio of the resin to the oil may be from 5:1 to 1:5, preferably from 4.5:1 to 1:4.5, more preferably from 4:1 to 1:4, still more preferably from 3.5:1 to 1:3.5, more preferably still from 3:1 to 1:3, especially from 3:1 to 1:2. A weight ratio of resin and oil of about 2.8:1 is preferred for many embodiments. The weight ratio of the solvent to the oil may be from 5:1 to 1:5, preferably from 4.5:1 to 1:4.5, more preferably from 4:1 to 1:4, still more preferably from 3.5:1 to 1:3.5, more preferably still from 3:1 to 1:3, especially from 3:1 to 1:2. A weight ratio of solvent and oil of about 2.8:1 is preferred for many embodiments. In embodiments where the sealant composition is for applying by spraying, the weight ratio of the resin to the solvent may be from 2:1 to 1:6, preferably from 1.5:1 to 1:5, more preferably from 1.5:1 to 1:4.5, still more preferably from 1.5:1 to 1:4, more preferably still from 1.5:1 to 1:3.5, especially from 1.5:1 to 1:3, more especially from 1.5:1 to 1:2.5. A weight ratio of resin and solvent of about 1:2.2 is preferred for many embodiments. The weight ratio of the resin to the oil may be from 5:1 to 1:5, preferably from 4.5:1 to 1:4.5, more preferably from 4:1 to 1:4, still more preferably from 3.5:1 to 1:3.5, more preferably still from 3:1 to 1:3, especially from 3:1 to 1:2. A weight ratio of resin and oil of about 2.8:1 is preferred for many embodiments. The weight ratio of the solvent to the oil may be from 10:1 to 1:5, preferably from 9.5:1 to 1:4.5, more preferably from 9:1 to 1:4, still more preferably from 8.5:1 to 1:3.5, more preferably still from 8:1 to 1:3, especially from 7.5:1 to 1:2, more especially from 7:1 to 1:1.5, still more especially from 6.5:1 to 1:1.5. A weight ratio of solvent and oil of about 6.2:1 is preferred for many embodiments. The sealant composition of the present invention may comprise one or more further components, as known and employed in the art. For example, the composition may comprise one or more pigments. Suitable pigments are known in the art and are commercially available. The composition may comprise one or more fillers, as is also known in the art. Suitable fillers are generally inert materials and include powdered minerals, such as calcium carbonate. In one preferred embodiment, the sealant composition of the present invention consists essentially of the resin, oil and solvent described hereinbefore. An advantage of the sealant composition of the present invention is that it may be formed by a relatively simple method, which may be applied at a wide range of scales. According to a further aspect of the present invention, there is provided a method for forming a sealant composition, the method comprising combining a resin, an oil and a solvent. In a preferred embodiment, it is preferred to subject the resin to a pretreatment comprising heating the resin to form a liquid resin; cooling the liquid to form a solid resin; and comminuting the solid resin to form a divided solid resin material. The temperature to which the resin is heated will depend upon the melting point of the resin. For example, in one preferred embodiment, in which the resin comprises rosin, the resin is heated to a temperature of from 120 to 180°C. The liquid resin is cooled. Cooling may be achieved by allowing the resin to cool at ambient temperature. Alternatively, the liquid resin may be cooled more rapidly at a temperature below ambient temperature. The liquid resin is cooled until it has completely solidified. Finally, the resulting solid resin is comminuted to form a divided solid resin material. Comminution may be achieved using any suitable technique, for example crushing and / or grinding. Suitable techniques and apparatus for communition of the solid resin are known in the art The solid resin is comminuted to form a divided resin material having a particle size that allows the resin readily to dissolve in the solvent. A suitable particle size is in the range of from 500 to 2500 pm, more preferably from 1000 to 2000 pm. The resin, the oil and the solvent may be combined in any suitable order. In one preferred embodiment, the resin, preferably in a finely divided form, is first combined with the solvent, whereby the resin dissolves in the solvent to produce a resin solution. Thereafter, the resin solution is combined with the oil. The resin and the solvent may be combined in any suitable manner to produce a resin solution. Preferably, the resin and solvent are combined with agitation, such as mixing or stirring. The resin and solvent may be combined at ambient temperature. Alternatively, the resin and solvent may be combined at an elevated temperature above ambient temperature, to aid dissolution of the resin in the solvent. The resin and the solvent may be combined in any suitable ratio. For example, the resin and the solvent may be combined in a weight ratio of from 1:6 to 6:1, preferably from 1:5 to 5:1, more preferably from 1:4 to 4:1, still more preferably from 1:4 to 3:1. In one preferred embodiment, the resin and the solvent are combined in a weight ratio of from 1:4 to 2.33:1. Once formed, the resin / solvent solution is combined with the oil. The resin solution and the oil may be combined in any suitable manner to form the sealant composition. Preferably, the resin solution and the oil are combined with agitation, such as mixing or stirring. The resin solution and the oil may be combined at ambient temperature. More preferably, the resin solution and the oil are combined at an elevated temperature above ambient temperature, to aid mixing. The elevated temperature reduces the viscosity of the mixture and allows a homogeneous mixture of the resin, solvent and oil to be more readily obtained. The resin solution and the oil may be combined in any suitable ratio. For example, the resin solution and the oil may be combined in a weight ratio of from 12:1 to 1:6, preferably from 11:1 to 1:5, more preferably from 10:1 to 1:4, still more preferably from 9:1 to 1:3. In one preferred embodiment, the resin and the solvent are combined in a weight ratio of from 9:1 to 1:2.33. The composition obtained by the aforementioned method steps is a sealant composition that is suitable for application by spreading, for example using a brush or a spreader. To prepare a composition that is suitable for application by spraying, further solvent may be added to the composition produced by the aforementioned method steps, to render the composition sprayable through a nozzle. For example, the sealant composition and the solvent may be combined in a weight ratio of from 1:12 to 4:1, preferably from 1:11 to 3.5:1, more preferably from 1:10 to 3:1, still more preferably from 9.5:1 to 2:1. In one preferred embodiment, the sealant composition and the solvent are combined in a weight ratio of from 1:9 to 1.5:1. The sprayable sealant composition may be dispensed using any suitable spray apparatus. In one embodiment, the sprayable sealant composition is loaded into a pressurised container, in particular an aerosol can, as is well known in the art. The sealant composition offers a number of technical advantages compared with known sealant compositions. In particular, the composition may be prepared from resin and oil components that are naturally occurring and may be produced on a renewable basis, resulting in reduced environmental impact. Further, the sealant composition may be prepared from components that are safe and present little or no hazard to users and the environment. In particular, naturally occurring resins, such as those extracted from trees, in particular rosin, are generally identified as being safe to handle, with little or no toxic effects. Further, naturally occurring oils extracted from plants, such as castor oil, are generally identified as being safe to handle, with little or no toxic effects. Finally, the composition may employ solvents which are considered to be safe. For example, acetone, a preferred solvent, is recognised as being safe for use in the food industry. Embodiments of the present invention will now be described, for illustrative purposes only, byway of the following working examples. Unless otherwise indicated, percentages are weight percent. EXAMPLES Example 1 Spreadable Sealant Composition A spreadable sealant composition was prepared from the following components: Resin (Carbofen®, ex. Polytrade) Solvent (Acetone) Oil (Castor Oil) 42.5 wt% 42.5 wt% 15.0 wt% The sealant composition was prepared using the following method. In a first stage, the resin was heated to a temperature of from 120 to 180°C to form a viscous liquid. The liquid was cooled by allowing to stand at ambient temperature to form a solid. The resulting solid was crushed and pulverised to form a powder having an average particle size of from 1000 pm to 2000 pm. In a second stage, the powder produced in the first stage was combined with the solvent under stirring at ambient temperature until the powdered resin has fully dissolved in the solvent. When using stirring, complete dissolution of the powder in the solvent was obtained in a time of from 4 to 12 hours. As an alternative, the powdered resin may be combined with the solvent without stirring. Under these conditions, complete dissolution of the powdered resin in the solvent may take from 8 to 24 hours. In a third stage, the solution obtained in the second stage was heated to a temperature of from 30 to 50°C and combined with the oil with stirring. Stirring was provided using a paddle mixer operating at a speed of 60 rpm for a period of from 20 to 40 minutes. Thereafter, the resulting mixture was allowed to cool at ambient conditions to ambient temperature. The resulting composition may be used directly as a sealant. The composition may be applied to surfaces to be sealed by any suitable means, such as a spreader or a brush. The composition has been found to be easy to apply in an even coat and to have excellent sealing properties, in particular when used to form a fluid-tight joint between the surfaces of two components. Example 2 Sprayable Sealant Composition A sprayable sealant composition was prepared from the following components: Resin (Carbofen®, ex. Polytrade) Solvent (Acetone) Oil (Castor Oil) 28.0 wt% 62.0 wt% 10.0 wt% The sealant composition was prepared using the following method. In a first stage, the resin was heated to a temperature of from 120 to 180°C to form a viscous liquid. The liquid was cooled by allowing to stand at ambient temperature to form a solid. The resulting solid was crushed and pulverised to form a powder having an average particle size of from 1000 pm to 2000 pm. In a second stage, the powder produced in the first stage was combined with a portion (0.68) of the solvent under stirring at ambient temperature until the powdered resin has fully dissolved in the solvent. When using stirring, complete dissolution of the powder in the solvent was obtained in a time of from 4 to 12 hours. As an alternative, the powdered resin may be combined with the solvent without stirring. Under these conditions, complete dissolution of the powdered resin in the solvent may take from 8 to 24 hours. In a third stage, the solution obtained in the second stage was heated to a temperature of from 30 to 50°C and combined with the oil with stirring. Stirring was provided using a paddle mixer operating at a speed of 60 rpm for a period of from 20 to 40 minutes. Thereafter, the resulting mixture was allowed to cool at ambient conditions to ambient temperature. The resulting mixture was combined with the remaining portion (0.32) of the solvent with mixing at ambient temperature. The resulting composition was loaded into an aerosol can fitted with a fan-pattern spray nozzle. The composition may be applied to surfaces to be sealed from the aerosol in a conventional manner. The composition has been found to be easy to apply to surfaces with an even coverage and to have excellent sealing properties, in particular when used to form a fluid-tight joint between the surfaces of two components.

Claims

1. A sealant composition comprising:a resin;an oil; anda solvent.

2. The sealant composition according to claim 1, wherein the resin comprises one or more naturally occurring resins or derivatives thereof.

3. The sealant composition according to claim 2, wherein the resin comprises a resin extracted from a resinous plant.

4. The sealant composition according to claim 3, wherein the resin comprises a resin extracted from one or more parts of a tree.

5. The sealant composition according to claim 4, wherein the resin comprises a resin extracted from trees of the genus Pinus or Araucaria.

6. The sealant composition according to claim 5, wherein the resin comprises a resin extracted from trees of the species Araucaria angustifolia (common name Parana pine, Brazilian pine or candelabra tree).

7. The sealant composition according to any preceding claim, wherein the resin comprises rosin or a derivative thereof.

8. The sealant composition according to any preceding claim, wherein the resin is present in an amount of from 20 to 60% by weight.

9. The sealant composition according to any preceding claim, wherein the oil comprises a naturally occurring oil.

10. The sealant composition according to claim 9, wherein the oil comprises castor oil, coconut oil (copra oil), colza oil, corn oil, cottonseed oil, false flax oil, hemp oil, mustard oil,palm oil, peanut oil, radish oil, rapeseed oil, ramtil oil, rice bran oil, safflower oil, salicornia oil, soybean oil, sunflower oil, tigernut oil, tung oil, copaiba oil, jatropha oil, jojoba oil, milk bush, nahor oil, paradise oil, petroleum nut oil, or pongamia oil (also known as honge oil).

11. The sealant composition according to claim 10, wherein the oil comprises castor oil, coconut oil, corn oil, rapeseed oil, colza oil, sunflower oil, palm oil, soybean oil or a mixture thereof.

12. The sealant composition according to any preceding claim, wherein the oil is present in an amount of from 2 to 30% by weight.

13. The sealant composition according to any preceding claim, wherein the solvent is selected from aldehydes, carboxylic acids, esters, ethers, ketones, terpenes and alcohols.

14. The sealant composition according to claim 13, wherein the solvent comprises a C2 to Ce aldehyde, a C2 to Ce carboxylic acid, a C3 to Cs ester, a C2 to Ce ether, a C3 to Cs ketone, an alpha- or beta-pinene, carene, camphene, limonene, and terpinolene, ora C2 to Cs alcohol.

15. The sealant composition according to either of claims 13 or 14, wherein the solvent comprises a ketone.

16. The sealant composition according to claim 15, wherein the ketone is acetone.

17. The sealant composition according to any preceding claim, wherein the solvent ispresent in an amount of from 10 to 85% by weight.

18. The sealant composition according to claim 17, wherein the composition is a sprayable composition and the solvent is present in an amount of from 30 to 65% by weight.

19. The sealant composition according to wherein the composition is a spreadable composition and the solvent is present in an amount of from 25 to 60% by weight.

20. The sealant composition according to any preceding claim, wherein the weight ratio of the resin to the solvent in the composition is from 6:1 to 1:6, and / or the weight ratio of the resin to the oil in the composition is from 5:1 to 1:5, and / or the weight ratio of the solvent to the oil in the composition is from 10:1 to 1:5.

21. A method for forming a sealant composition, the method comprising combining a resin, an oil and a solvent.

22. The method according to claim 21, wherein the resin is subjected to a pretreatment 5 comprising heating the resin to form a liquid resin; cooling the liquid to form a solid resin;and comminuting the solid resin to form a divided solid resin material.

23. The method according to claim 22, wherein the comminuted resin has a particle size is in the range of from 500 to 2500 pm.

24. The method according to any of claims 21 to 23, wherein the resin is first combined 10 with the solvent, whereby the resin dissolves in the solvent to produce a resin solution, after which the resin solution is combined with the oil.

25. The method according to claim 24, further comprising combining the resulting composition with further solvent.15