Coating composition

Abstract

Use of a rheology modifier in a coating composition, wherein when the coating composition is applied to at least a portion of a substrate, the rheology modifier is used to enhance the chemical resistance of the coating formed from the coating composition, and wherein the rheology modifier comprises at least 85 wt% of a compound having a melting temperature greater than 95 °C.

Description

Technical Field

[0001] The present invention relates to the use of a rheology modifier in a coating composition to enhance the chemical resistance of a coating formed from the coating composition, such as when the coating is applied to at least a portion of a substrate, such as a steel substrate, such as a storage tank or a pipeline. The present invention also relates to a substrate (such as a storage tank or a pipeline having such a coating applied to at least a portion of a surface (such as an inner surface)) and a method of producing such a coated substrate (such as a storage tank or a pipeline). The present invention also relates to a coating composition that can be applied to at least a portion of a substrate, such as a storage tank or a pipeline. Background Art

[0002] In the chemical storage and transportation industry, containers and processing equipment for processing, storing, handling, and / or transporting products such as chemicals and / or solvents will typically include a coating composition applied to an inner surface to provide protection thereto. Such containers and processing equipment can include pipeline internals, onshore and offshore storage tanks, marine storage tanks, potable water storage tanks, ballast tanks, and the like.

[0003] Coating compositions applied to the inner surfaces of containers and processing equipment are typically formed from organic or inorganic materials such as epoxy resins, silicates, polyureas, polyurethanes, vinyl esters, polyolefin systems, or combinations of such technologies. The coated surfaces will typically be formed from steel. During use, the coated surfaces are exposed to long-term exposure to various crude or refined products or chemicals in the liquid or gas phase, such as acids, bases, oils, fats, solvents (such as alcohols, ketones, ethers, hydrogenated hydrocarbons), and water.

[0004] In order to function effectively in a wide range of applications, such as being suitable as a chemical storage tank coating for a wide range of cargoes, coating compositions need to meet a series of demanding and complex specifications. Such specifications include operating efficiency (fast cargo change, short recovery time, early water wash), increased cargo temperature (to enhance the pumpability of viscous cargoes), higher levels of erosive contamination (alkaline / acidic conditions, etc.), and the cargo / water wash sequence places high demands on the performance and service life of the storage tank coating. Summary of the Invention

[0005] According to the present invention, there is provided the use of a rheology modifier in a coating composition, wherein the rheology modifier is used to enhance the chemical resistance of a coating formed from the coating composition when the coating composition is applied to at least a portion of a substrate, and wherein the rheology modifier comprises at least 85 wt% of a compound having a melting temperature greater than 95 °C.

[0006] There is also provided a coating composition comprising a rheology modifier, wherein the rheology modifier comprises at least 85 wt% of a compound having a melting temperature greater than 95 °C.

[0007] There is also provided a substrate, at least a portion of which is coated with a coating formed by applying the coating composition described herein to the substrate.

[0008] There is also provided a storage tank or pipeline, at least a portion of the inner surface of which is coated with a coating formed by applying the coating composition described herein to the substrate.

[0009] There is also provided a method for producing a substrate, at least a portion of which is coated with a coating, the method comprising the steps of:

[0010] (a) providing a coating composition as described herein; and

[0011] (b) applying the composition to at least a portion of the substrate to form a coating. Detailed Description

[0012] According to the present invention, there is provided the use of a rheology modifier in a coating composition, which is used to enhance the chemical resistance of a coating formed from the coating composition when the coating composition is applied to at least a portion of a substrate, wherein the rheology modifier comprises at least 85 wt% of a compound having a melting temperature greater than 95 °C.

[0013] The mention of "at least 85 wt% of a compound having a melting temperature greater than 95 °C" means at least 85 wt% based on the total weight of the rheology modifier.

[0014] As used herein, "rheology modifier" means an additive that changes the rheology of a coating composition containing the rheology modifier. The rheology modifier of the present invention may include a thixotropic agent. As used herein, "thixotropic agent" means an additive that imparts thixotropic properties to a coating composition containing the thixotropic agent.

[0015] The rheology modifier can provide anti-sagging properties to the coating (also known as the retention of a wet coating on a vertical substrate) and prevent the precipitation of particles such as pigments in the coating composition (such as during the storage of the coating composition). Surprisingly, it has been found that the rheology modifier plays an important role in the chemical resistance of the coating (as a layer) on a substrate such as a steel surface. Specifically, it has been found that a rheology modifier having specific melting characteristics can be used to advantageously enhance or increase the chemical resistance of the coating to chemicals such as fatty acids (especially hot chemicals, such as fatty acids) and / or to organic solvents (such as aggressive organic solvents).

[0016] Therefore, by enhancing the chemical resistance, the rheology modifier can provide a coated substrate with improved expected life, robustness, operating efficiency (reducing coating repair between cargos, reducing ventilation time, reducing strict restrictions in service), accepting higher cargo temperatures and increased cargo versatility.

[0017] As used herein, the term "coating formed from a coating composition when applied to at least a portion of a substrate" refers to a coating applied to a substrate in a suitable thickness.

[0018] As used herein, "enhanced chemical resistance" of a coating means that when the coating includes a rheology modifier, the coating has chemical resistance determined as follows, where the chemical resistance can be increased compared to a coating formed from the same coating composition that does not include a rheology modifier as defined herein (i.e., does not include any rheology modifier or includes a rheology modifier not defined herein).

[0019] As reported herein, the chemical resistance of a coating (such as when applied as a layer to a substrate) is determined according to ISO 2812-1:2007. The use of a rheology modifier as described herein can provide chemical resistance to a coating determined according to ISO 2812-1:2007.

[0020] The chemical resistance of a coating to continuous exposure to a chemical can be determined by continuously immersing a panel including the coating in the chemical for a duration of 6 months. The coating is inspected for defects at fixed time intervals (such as monthly). The chemical resistance of a coating to repeated cycles of a chemical can be determined by intermittently exposing a panel including the coating to the chemical and inspecting the coating for defects. The coating can be immersed in a first chemical for 3 weeks, followed by immersion in water for 3 weeks, and the cycle repeated at least 10 times. Alternatively, the coating can be immersed in a first chemical for a period of 7 days, washed with water, immersed in a second chemical for 7 days, washed with water, and the cycle repeated at least 10 times.

[0021] Defects in the coating include blistering, cracking, swelling, delamination, softening, discoloration, loss of adhesion, and subfilm corrosion. The degree of blistering can be evaluated by examining the size and number of blisters, such as the number of blisters in the range of 0.5 mm to 2 mm in size, the number of blisters in the range of 2 mm to 5 mm in size, and the number of blisters in the range of 5 mm to 10 mm in size. As reported herein, the degree of blistering is determined according to ISO4628-2:2016.

[0022] If a coating remains intact after exposure (i.e., contact) to a chemical, the coating can be considered to have chemical resistance to the chemical. As used herein, "intact" means that the coating does not have structural defects such as blistering, cracking, swelling, and delamination. Structural defects in the coating can lead to a loss of coating integrity and may result in contact between the chemical and the substrate.

[0023] The rheological agent can enhance the chemical resistance of the coating to any known chemical, whether it is a liquid, semi-solid or solid. The chemical can be a liquid. The chemical can be a chemical cargo. The chemical can include acids (such as organic acids or inorganic acids), bases, oils, fats, solvents (such as alcohols, ketones, ethers, hydrogenated hydrocarbons) and water.

[0024] The rheological agent can enhance the chemical resistance of the coating to long-term exposure and / or repeated cycles of chemicals.

[0025] As used herein, "long-term exposure" means continuous exposure to one or more chemicals for a total period of at least 6 months, such as at least 9 months, such as at least 12 months, such as at least 2 years, 3 years, 4 years or 5 years.

[0026] The rheological agent can enhance the chemical resistance of the coating to continuous exposure to chemicals for a total of at least 6 months, such as at least 9 months, such as at least 12 months. In other words, the rheological agent can enhance the chemical resistance of the coating such that the coating remains intact after continuous exposure to chemicals for a total of at least 6 months, such as at least 9 months, such as at least 12 months.

[0027] As used herein, "repeated cycles of chemicals" means that the coating is intermittently exposed to or in contact with more than one chemical.

[0028] The rheological agent can provide the coating with chemical resistance to repeated cycles of at least 2 different chemicals.

[0029] The rheological agent can enhance the chemical resistance of the coating to any organic solvent, such as alcohols, ketones, ethers and hydrogenated hydrocarbons. The rheological agent can enhance the chemical resistance of the coating to alcohols, such as methanol, ethanol or propanol. The rheological agent can enhance the chemical resistance of the coating to methanol.

[0030] The rheological agent can enhance the chemical resistance of the coating to fatty acids. The fatty acids can be derived from vegetable oils, such as palm oil. The rheological agent can enhance the chemical resistance of the coating to palm fatty acid distillate (PFAD). PFAD is a waste stream in the palm oil industry and is an aggressive cargo for epoxy resin-based coating systems. It consists of free fatty acids with different molecular weights and contains a portion of unsaturated fatty acids. PFAD can alternatively be prepared from individual fatty acids: lauric acid 0.1 wt%, myristic acid 0.5 wt%, palmitic acid 48 wt%, stearic acid 4.2 wt%, oleic acid 37.2 wt%, linoleic acid 9.6 wt% and linolenic acid 0.4 wt%. These fatty acids can be obtained from Acros Organics / Fisher Scientific.

[0031] The rheological agent can enhance the chemical resistance of the coating to organic solvents (such as methanol) and fatty acids (such as palm fatty acid distillate (PFAD)).

[0032] The rheological agent can enhance the chemical resistance of the coating by providing chemical resistance to fatty acids (such as palm fatty acid distillate (PFAD)) and / or to organic solvents (such as methanol) to the coating.

[0033] The rheological agent can enhance the chemical resistance of the coating by providing chemical resistance to fatty acids (such as palm fatty acid distillate (PFAD)) and to organic solvents (such as methanol) to the coating.

[0034] Elevated temperatures are generally used for loading / unloading chemical cargoes to improve pumpability and loading / unloading speed. The temperature range depends on the type of cargo, e.g., to achieve a suitable viscosity of the cargo. The present invention can enhance the chemical resistance of the coating within an elevated operating temperature range.

[0035] The rheological agent can enhance the chemical resistance of the coating to chemicals at a temperature of at least 40°C (such as at least 50°C, such as at least 60°C). The rheological agent can enhance the chemical resistance of the coating to organic solvents (such as methanol) at a temperature of at least 40°C. The rheological agent can enhance the chemical resistance of the coating to fatty acids (such as PFAD) at a temperature of at least 60°C (such as at least 70°C) (such as at 80°C).

[0036] The rheological agent can enhance the chemical resistance of the coating by providing chemical resistance to fatty acids at a temperature of at least 60°C and / or by providing chemical resistance to organic solvents at a temperature of at least 40°C.

[0037] The rheological agent can enhance the chemical resistance of the coating by providing chemical resistance to fatty acids at a temperature of at least 60°C and by providing chemical resistance to organic solvents at a temperature of at least 40°C.

[0038] The rheological agent can enhance the chemical resistance of the coating when continuously exposed to organic solvents (such as methanol) at a temperature of at least 40°C for a total of at least 6 months, such as at least 9 months, such as at least 12 months. The rheological agent can enhance the chemical resistance of the coating when continuously exposed to fatty acids (such as PFAD) at a temperature of at least 60°C for a total of at least 6 months, such as at least 9 months, such as at least 12 months. The rheological agent can enhance the chemical resistance of the coating when continuously exposed to PFAD at a temperature of at least 70°C for a total of at least 6 months, such as at least 9 months, such as at least 12 months.

[0039] Compared with a coating comprising castor oil and / or hydrogenated castor oil (i.e., instead of a rheology modifier), a rheology modifier can provide enhanced chemical resistance of the coating. Compared with a coating comprising castor oil and / or hydrogenated castor oil, a rheology modifier can provide enhanced chemical resistance of the coating to fatty acids such as PFAD. A coating as defined herein can have enhanced chemical resistance if it remains intact for a longer period of time compared with a coating comprising castor oil and / or hydrogenated castor oil.

[0040] The rheology modifier used in the present invention comprises at least 85 wt% of a compound having a melting temperature greater than 95 °C, such as greater than 105 °C, such as greater than 115 °C.

[0041] The rheology modifier used in the present invention comprises at least 85 wt%, such as at least 87 wt%, such as at least 90 wt% or even at least 94 wt% of a compound having a melting temperature greater than 95 °C. The rheology modifier used in the present invention comprises 85 wt% to 99 wt%, such as 87 wt% to 97 wt%, such as 88 wt% to 95 wt% of a compound having a melting temperature greater than 95 °C.

[0042] The rheology modifier used in the present invention comprises at least 85 wt%, such as at least 87 wt%, such as at least 90 wt% or even at least 94 wt% of a compound having a melting temperature greater than 95 °C, such as greater than 105 °C, such as greater than 115 °C. The rheology modifier used in the present invention comprises 85 wt% to 99 wt%, such as 87 wt% to 97 wt%, such as 88 wt% to 95 wt% of a compound having a melting temperature greater than 95 °C, such as greater than 105 °C, such as greater than 115 °C.

[0043] The rheology modifier can comprise at least 1 wt% of a compound having a melting temperature of at most 95 °C, such as at most 94 °C.

[0044] The rheology modifier can comprise at least 1 wt%, such as at least 3 wt%, such as at least 5 wt% of a compound having a melting temperature of at most 95 °C. The rheology modifier can comprise 1 wt% to 15 wt%, such as 3 wt% to 13 wt%, such as 5 wt% to 12 wt% of a compound having a melting temperature of at most 95 °C.

[0045] The rheology modifier can comprise at least 1 wt%, such as at least 3 wt%, such as at least 5 wt% of a compound having a melting temperature of at most 95 °C, such as at most 94 °C. The rheology modifier can comprise 1 wt% to 15 wt%, such as 3 wt% to 13 wt%, such as 5 wt% to 12 wt% of a compound having a melting temperature of at most 95 °C, such as at most 94 °C.

[0046] The rheology modifier can include at least 85 wt% of a compound having a melting temperature greater than 95 °C and at least 1 wt% of a compound having a melting temperature of at most 95 °C, such as at least 87 wt% of a compound having a melting temperature greater than 105 °C and at least 3 wt% of a compound having a melting temperature of at most 95 °C. The rheology modifier can include 85 wt% to 99 wt% of a compound having a melting temperature greater than 95 °C and 1 wt% to 15 wt% of a compound having a melting temperature of at most 95 °C, such as 87 wt% to 97 wt% of a compound having a melting temperature greater than 105 °C and 3 wt% to 13 wt% of a compound having a melting temperature of at most 95 °C, such as 88 wt% to 95 wt% of a compound having a melting temperature greater than 115 °C and 5 wt% to 12 wt% of a compound having a melting temperature of at most 95 °C.

[0047] As used herein, "melting temperature" means the temperature at which a compound is completely melted. As reported herein, the melting temperature is measured using differential scanning calorimetry. Differential scanning calorimetry is applicable to be carried out using the methods described in paragraphs

[0132] and

[0133] below.

[0048] The rheology modifier can include more than one compound. The compound having a melting temperature greater than 95 °C can include an organic compound. As used herein, "organic compound" means a compound including a carbon-hydrogen bond. The compound having a melting temperature greater than 95 °C can include a compound containing at least two amide groups such as a diamide or a polyamide. The compound including at least two amide groups can include a diamide.

[0049] The rheology modifier can be composed of a diamide, wherein at least 85 wt% of the diamide has a melting temperature greater than 95 °C, such as greater than 105 °C, such as greater than 115 °C.

[0050] The rheology modifier can be composed of a diamide, wherein at least 85 wt%, such as at least 87 wt%, such as at least 90 wt% or even at least 94 wt% of the diamide has a melting temperature greater than 95 °C. The rheology modifier can be composed of a diamide, wherein 85 wt% to 99 wt%, such as 87 wt% to 97 wt%, such as 88 wt% to 95 wt% of the diamide has a melting temperature greater than 95 °C.

[0051] The rheology modifier can be composed of a diamide, wherein at least 85 wt%, such as at least 87 wt%, such as at least 90 wt% or even at least 94 wt% of the diamide has a melting temperature greater than 95 °C, such as greater than 105 °C, such as greater than 115 °C. The rheology modifier can be composed of a diamide, wherein 85 wt% to 99 wt%, such as 87 wt% to 97 wt%, such as 88 wt% to 95 wt% of the diamide has a melting temperature greater than 95 °C, such as greater than 105 °C, such as greater than 115 °C.

[0052] The rheology modifier can be composed of diamides, wherein at least 1 wt% of the diamides have a melting temperature of at most 95 °C, such as at most 94 °C.

[0053] The rheology modifier can be composed of diamides, wherein at least 1 wt%, such as at least 3 wt%, such as at least 5 wt% of the diamides have a melting temperature of at most 95 °C. The rheology modifier can be composed of diamides, wherein 1 wt% to 15 wt%, such as 3 wt% to 13 wt%, such as 5 wt% to 12 wt% of the diamides have a melting temperature of at most 95 °C.

[0054] The rheology modifier can be composed of diamides, wherein at least 1 wt%, such as at least 3 wt%, such as at least 5 wt% of the diamides have a melting temperature of at most 95 °C, such as at most 94 °C. The rheology modifier can be composed of diamides, wherein 1 wt% to 15 wt%, such as 3 wt% to 13 wt%, such as 5 wt% to 12 wt% of the diamides have a melting temperature of at most 95 °C, such as at most 94 °C.

[0055] The rheology modifier can be composed of diamides, wherein at least 85 wt% of the diamides have a melting temperature greater than 95 °C and at least 1 wt% of the diamides have a melting temperature of at most 95 °C, such as at least 87 wt% of the diamides have a melting temperature greater than 105 °C and at least 3 wt% of the diamides have a melting temperature of at most 95 °C. The rheology modifier can be composed of diamides, wherein 85 wt% to 99 wt% of the diamides have a melting temperature greater than 95 °C and 1 wt% to 15 wt% of the diamides have a melting temperature of at most 95 °C, such as 87 wt% to 97 wt% of the diamides have a melting temperature greater than 105 °C and 3 wt% to 13 wt% of the diamides have a melting temperature of at most 95 °C, such as 88 wt% to 95 wt% of the diamides have a melting temperature greater than 115 °C and 5 wt% to 12 wt% of the diamides have a melting temperature of at most 95 °C.

[0056] Commercially available diamide-based rheology modifiers can include Crayvallac® Ultra, Crayvallac® Super, Crayvallac® LV, Crayvallac® Optima, and Crayvallac® PA3X20 obtained from Arkema; BYK-405 and BYK-430 obtained from BYK Altana Group; Luvotix® HP, Luvotix® AB, Luvotix® PA20XA, Luvotix® LT10, Luvotix® SAB, Luvotix® PAB, and Luvotix® SHP obtained from Lehmann & Voss; Thixatrol® MAX, Thixatrol® PRO, Thixatrol® PM8054, Thixatrol® PM8056, and Thixatrol® PM8058 obtained from Elementis; Iscathix® SR obtained from International Supply Chain Alliance Co., Ltd. (ISCA); Keperrhe®-400 obtained from Kito Chemicals; Disparlon® 6300, Disparlon® 6500, Disparlon® 6700, and Disparlon® 6900 20X obtained from Kusumoto Chemicals; and / or Flownon RCM-210 obtained from Kyoeisha Chemicals Co., Ltd.For example, commercially available diamide-based rheology modifiers can include Crayvallac(RTM) Ultra, Crayvallac(RTM) Super, Crayvallac(RTM) LV, Crayvallac(RTM) Optima, and Crayvallac(RTM) PA3X20 obtained from Arkema; BYK-405 and BYK-430 obtained from BYK Altana; Luvotix(RTM) HP, Luvotix(RTM) AB, Luvotix(RTM) PA20XA, Luvotix(RTM) LT10, Luvotix(RTM) SAB, Luvotix(RTM) PAB, and Luvotix(RTM) SHP obtained from Lehmann & Voss; Thixatrol(RTM) MAX, Thixatrol(RTM) PRO, Thixatrol(RTM) PM8054, Thixatrol(RTM) PM8056, and Thixatrol(RTM) PM8058 obtained from Elementis; Iscathix(RTM) SR obtained from International Supply Chain Alliance Co., Ltd.; Keperrhe(RTM)-400 obtained from Kito Chemicals; and / or Flownon RCM-210 obtained from Kyoeisha Chemical Co., Ltd.

[0057] The diamide can include a compound of formula (I):

[0058] R1-CONH-X1-NHCO-R2 (I)

[0059] wherein X1 is a hydrocarbylene group; and

[0060] R1 and R2 are each independently a hydrocarbyl group optionally substituted with a hydroxyl group.

[0061] The diamide can include a compound of formula (II):

[0062] R3-NHCO-X2-NHCO-R4 (II)

[0063] wherein X2 is a hydrocarbylene group; and

[0064] R3 and R4 are each independently a hydrocarbyl group optionally substituted with a hydroxyl group.

[0065] The diamide can include a compound of formula (III):

[0066] R5-NHCO-X3-CONH-R6 (III)

[0067] wherein X3 is a hydrocarbylene group; and

[0068] R5 and R6 are each independently a hydrocarbyl group optionally substituted with a hydroxy group.

[0069] The diamide can include a mixture of compounds of formula (I), formula (II) and formula (III). The diamide can include a compound of formula (I).

[0070] The compound of formula (I) can be obtained by reacting a diamine of formula H2N-X1-NH2 with carboxylic acids of formula R1-COOH and R2-COOH, wherein X1, R1 and R2 are as defined above.

[0071] The compound of formula (II) can be obtained by reacting an amino acid of formula HOOC-X2-NH2 with an amine of formula R3-NH2 and a carboxylic acid of formula R4-COOH, wherein X2, R3 and R4 are as defined above.

[0072] The compound of formula (III) can be obtained by reacting a dicarboxylic acid of formula HOOC-X3-COOH with amines of formula R5-NH and R6-NH, wherein X3, R5 and R6 are as defined above.

[0073] X1 as defined herein can be an alkylene group, an alkenylene group, an arylene group, an aralkyl group or an alkylalkylene group. X1 can include from 1 to 20, such as from 1 to 10, such as from 1 to 8 carbon atoms. X1 can be C1-C 20 alkylene group, C2-C 20 alkenylene group, C6-C 20 arylene group, C7-C 20 aralkyl group or C8-C 20 alkylalkylene group. X1 can represent a straight-chain C1-C8 alkylene group or a C8 alkylalkylene group. X1 can be 1,2-ethylene, 1,6-hexylene or 1,3-benzenedimethyl.

[0074] R1 and R2 as defined herein can each independently be an alkyl group, an alkenyl group, an aryl group, an aralkyl group or an alkylalkyl group optionally substituted with a hydroxy group, such as one hydroxy group. R1 and R2 can each independently include from 1 to 20, such as from 10 to 20, such as from 16 to 18 carbon atoms. R1 and R2 can each independently represent a straight-chain C 10 -C 20 alkyl group, a straight-chain C 10 -C 20 hydroxyalkyl group, a straight-chain C 10 -C 20 alkenyl group or a straight-chain C 10 -C 20Hydroxyalkenyl group. R1 and R2 can each independently be n-decyl, n-hexadecyl, n-octadecyl or 12-hydroxy-n-octadecyl.

[0075] X2 as defined herein can be an alkylene group, an alkenylene group, an arylene group, an aralkyl group or an alkylalkylene group. X2 can include from 1 to 20, such as from 1 to 10, such as from 1 to 8 carbon atoms. X2 can be C1-C 20 alkylene group, C2-C 20 alkenylene group, C6-C 20 arylene group, C7-C 20 aralkyl group or C8-C 20 alkylalkylene group. X2 can represent a straight-chain C1-C8 alkylene group or a C8 alkylalkylene group. X2 can be 1,2-ethylene, 1,6-hexylene or 1,3-benzenedimethyl.

[0076] R3 and R4 as defined herein can each independently be an alkyl group, an alkenyl group, an aryl group, an aralkyl group or an alkylalkyl group optionally substituted by a hydroxy group, such as one hydroxy group. R3 and R4 can each independently include from 1 to 20, such as from 10 to 20, such as from 16 to 18 carbon atoms. R3 and R4 can each independently represent a straight-chain C 10 -C 20 alkyl group, a straight-chain C 10 -C 20 hydroxyalkyl group, a straight-chain C 10 -C 20 alkenyl group or a straight-chain C 10 -C 20 hydroxyalkenyl group. R3 and R4 can each independently be n-decyl, n-hexadecyl, n-octadecyl or 12-hydroxy-n-octadecyl.

[0077] X3 as defined herein can be an alkylene group, an alkenylene group, an arylene group, an aralkyl group or an alkylalkylene group. X3 can include from 1 to 20, such as from 1 to 10, such as from 1 to 8 carbon atoms. X3 can be C1-C 20 alkylene group, C2-C 20 alkenylene group, C6-C 20 arylene group, C7-C 20 aralkyl group or C8-C 20 alkylalkylene group. X3 can represent a straight-chain C1-C8 alkylene group or a C8 alkylalkylene group. X3 can be 1,2-ethylene, 1,6-hexylene or 1,3-benzenedimethyl.

[0078] R5 and R6 as defined herein can each independently be an alkyl group, alkenyl group, aryl group, aralkyl group or alkaryl group optionally substituted by a hydroxy group, such as a hydroxy group. R5 and R6 can each independently comprise from 1 to 20, such as from 10 to 20, such as from 16 to 18 carbon atoms. R5 and R6 can each independently represent a straight-chain C 10 -C 20 alkyl group, straight-chain C 10 -C 20 hydroxyalkyl group, straight-chain C 10 -C 20 alkenyl group or straight-chain C 10 -C 20 hydroxyalkenyl group. R5 and R6 can each independently be n-decyl, n-hexadecyl, n-octadecyl or 12-hydroxy-n-octadecyl.

[0079] Unless otherwise defined, the term "alkyl (alk or alkyl)" as used herein refers to a saturated hydrocarbon group in the form of a straight-chain, branched-chain, cyclic or polycyclic moiety or a combination thereof and can contain from 1 to 20 carbon atoms, such as from 1 to 10 carbon atoms, such as from 1 to 8 carbon atoms, such as from 1 to 6 carbon atoms or even from 1 to 4 carbon atoms. These groups can optionally be substituted by chlorine, bromine, iodine, cyano, nitro, -OR 19 、-OC(O)R 20 、C(O)R 21 、C(O)OR 22 、-NR 23 R 24 、C(O)NR 25 R 26 、-SR 27 、C(O)SR 27 、C(S)NR 25 R 26 、aryl or Het substituents (wherein R 19 to R 27 each independently represent hydrogen, aryl or alkyl) and / or interrupted by an oxygen atom or a sulfur atom or by a silyl group or a dialkylsiloxane group. Such groups can independently be selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, pentyl, isopentyl, hexyl, cyclohexyl, 3-methylpentyl, octyl, etc. As used herein, the term "alkylene" refers to a divalent alkyl group as defined above. For example, an alkyl group such as methyl represented as -CH3 becomes a methylene group -CH2- when represented as an alkylene. Other alkylenes should be understood accordingly.

[0080] As used herein, the term "alkenyl" refers to a hydrocarbon group having one or several, such as up to 4 double bonds, being straight-chain, branched-chain, cyclic or polycyclic moieties or combinations thereof and may contain 2 to 18 carbon atoms, such as 2 to 10 carbon atoms, such as 2 to 8 carbon atoms, such as 2 to 6 carbon atoms or even 2 to 4 carbon atoms. These groups may optionally be substituted by hydroxyl, chlorine, bromine, iodine, cyano, nitro, -OR 19 、-OC(O)R 20 、-C(O)R 21 、-C(O)OR 22 、-NR 23 R 24 、-C(O)NR 25 R26、-SR 27 、-C(O)SR 27 、-C(S)NR 25 R 26 or aryl substituents (wherein R 19 to R 27 each independently represents hydrogen, aryl or alkyl) and / or interrupted by an oxygen atom or a sulfur atom or by a silane or a dialkylsiloxanyl group. Such groups may independently be selected from alkenyl groups, including vinyl, allyl, isopropenyl, pentenyl, hexenyl, heptenyl, cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, 1-propenyl, 2-butenyl, 2-methyl-2-butenyl, isoprenyl, farnesyl, geranyl, geranylgeranyl, etc. As used herein, the term "alkenylene" refers to a divalent alkenyl group as defined above. For example, an alkenyl group such as vinyl represented as –CH=CH2 becomes vinylene -CH=CH- when represented as an alkenylene group. Other alkenylene groups should be understood accordingly.

[0081] As used herein, the term "aryl (ar or aryl)" refers to an organic group derived from an aromatic hydrocarbon by removing one hydrogen, and includes any monocyclic, bicyclic or polycyclic carbocyclic ring having up to 7 members in each ring, wherein the ring is aromatic. These groups may optionally be substituted by hydroxyl, chlorine, bromine, iodine, cyano, nitro, -OR 19 、-OC(O)R 20 、-C(O)R 21 、-C(O)OR 22 、-NR 23 R 24 、-C(O)NR 25 R 26 、-SR 27 、-C(O)SR 27 、-C(S)NR 25 R 26 or aryl substituents (wherein R 19 to R27 each independently represents hydrogen, aryl or lower alkyl) and / or interrupted by an oxygen atom or a sulfur atom or by a silyl group or a dialkylsiloxane group. Such groups may independently be selected from phenyl, p-tolyl, 4-methoxyphenyl, 4-(tert-butoxy)phenyl, 3-methyl-4-methoxyphenyl, 4-fluorophenyl, 4-chlorophenyl, 3-nitrophenyl, 3-aminophenyl, 3-acetamidophenyl, 4-acetamidophenyl, 2-methyl-3-acetamidophenyl, 2-methyl-3-aminophenyl, 3-methyl-4-aminophenyl, 2-amino-3-methylphenyl, 2,4-dimethyl-3-aminophenyl, 4-hydroxyphenyl, 3-methyl-4-hydroxyphenyl, 1-naphthyl, 2-naphthyl, 3-amino-1-naphthyl, 2-methyl-3-amino-1-naphthyl, 6-amino-2-naphthyl, 4,6-dimethoxy-2-naphthyl, tetrahydronaphthyl, indanyl, biphenyl, phenanthryl, anthryl or acenaphthylenyl, etc. As used herein, the term "arylene" refers to a divalent aryl group as defined above. For example, when represented as arylene, an aryl such as phenyl represented as –Ph becomes phenylene –Ph-. Other arylene groups should be understood accordingly.

[0082] To avoid doubt, references in this text to alkyl, alkenyl, aryl, aralkyl or alkalkyl in a composite group should be interpreted accordingly. For example, the reference to alkyl in aminoalkyl or the reference to alkyl in alkoxy should be interpreted as the above alkyl (alk or alkyl), etc.

[0083] The rheological agent may be substantially free of castor oil and hydrogenated castor oil. As used herein, "substantially free of" means that a particular component (such as castor oil), if present, is present in trace amounts (i.e., less than 0.1 wt%, such as less than 0.01 wt%). The rheological agent may be completely free of castor oil and hydrogenated castor oil. The rheological agent may be substantially free of vegetable oil and hydrogenated vegetable oil. The rheological agent may be completely free of vegetable oil and hydrogenated vegetable oil. The so-called "vegetable oil" or "castor oil" refers to triglycerides, rather than, for example, free fatty acids.

[0084] Commercially available rheological agents based on hydrogenated castor oil include Luvotix(RTM)R and Luvotix(RTM)HT obtained from Lehmann & Voss & Co.; Thixcin(RTM)R and Thixatrol(RTM)ST obtained from Elementis; Crayvallac(RTM)MT and Flowtone(RTM)GR obtained from Arkema; Rheocin(RTM) obtained from BYK Altana Group; and Iscathix(RTM)ISP and Iscathix(RTM)T obtained from International Supply Chain Alliance Co., Ltd. These rheological agents include at least 80 wt% of compounds with a melting temperature below 95 °C.

[0085] A coating composition comprising a rheology modifier is applied to at least a portion of a substrate to provide a coating thereon. The coating may comprise a single coating of the coating composition. Alternatively, the coating may comprise two or more coatings of the coating composition. The coating may comprise 2 or 3 coatings of the coating composition. Each coating of the coating composition may be the same or a different type of coating composition. The coating may comprise a primer layer and a topcoat. The coating may be formed by applying a coating of the coating composition as described herein to at least a portion of the substrate.

[0086] The coating may have any suitable thickness. The dry film thickness of the coating may be from 200 μm to 2000 μm, such as from 250 μm to 1000 μm, such as from 300 μm to 500 μm. When the coating is formed by applying a solvent-based coating composition, the dry film thickness of the coating may be from 200 μm to 1000 μm, such as from 250 μm to 600 μm, such as from 300 μm to 500 μm.

[0087] The substrate may be any suitable substrate, such as a metal substrate and / or a concrete substrate. The metal substrate may include steel; cast iron; metal alloys, such as alloys of aluminum or steel; non-ferrous metals, such as brass, bronze, and copper and combinations thereof. The substrate may include a steel substrate.

[0088] The substrate may be a storage tank or a pipeline having an inner surface, and at least a portion of the inner surface is coated with the coating. The inner surface may include an inner steel surface. The substrate may include a storage tank or a pipeline comprising an inner steel surface. The storage tank or the pipeline may be any storage tank or pipeline suitable for the chemical storage and transportation industry.

[0089] The present invention may provide the use of a rheology modifier in a coating composition, wherein when the coating composition is applied to at least a portion of a substrate, the rheology modifier is used to enhance the chemical resistance of the coating formed by the coating composition, wherein the chemical resistance includes resistance to continuous exposure to a fatty acid (such as PFAD) at a temperature of at least 60 °C (such as 70 °C) for a total of at least 6 months, and wherein the rheology modifier comprises at least 85 wt% of a diamide having a melting temperature greater than 95 °C.

[0090] The present invention may provide the use of a rheology modifier in a coating composition, wherein when the coating composition is applied to at least a portion of a substrate, the rheology modifier is used to enhance the chemical resistance of the coating formed by the coating composition, wherein the chemical resistance includes resistance to continuous exposure to an organic solvent (such as an alcohol, such as methanol) at a temperature of at least 40 °C for a total of at least 6 months, and wherein the rheology modifier comprises at least 85 wt% of a diamide having a melting temperature greater than 95 °C.

[0091] The present invention also provides a coating composition comprising a rheology modifier, wherein the rheology modifier comprises at least 85 wt% of a compound having a melting temperature greater than 95 °C.

[0092] Suitable characteristics and advantages of the rheology modifier included in the coating composition of the present invention are as described above with respect to the use.

[0093] The rheology modifier can be present in the coating composition in any suitable amount. Based on the total solids weight of the coating composition, the rheology modifier can be present in the coating composition in an amount of 0.1 wt% to 2.0 wt%, such as 0.5 wt% to 1.5 wt%, such as 0.8 wt% to 1.2 wt%.

[0094] The coating composition can include a binder resin. Any suitable binder resin can be used. Suitable binder resins are well known to those skilled in the art. The binder resin can include epoxy resins, amine resins, polyurethane resins, polyurea resins, vinyl ester resins, polyolefin resins, or combinations thereof. The binder resin can include epoxy resins, such as epoxy phenolic resins. The functionality of the epoxy phenolic resin can be at least 3.0 and the epoxy equivalent is less than 190 g / eq. As used herein, "functionality" means the number of epoxy groups per molecule. The epoxy equivalent is calculated by dividing the molecular weight of the molecule by its functionality (i.e., the number of epoxy groups per molecule).

[0095] The binder resin can be present in the coating composition in any suitable amount. Based on the total solids weight of the coating composition, the binder resin can be present in the coating composition in an amount of 1 wt% to 50 wt%, such as 10 wt% to 45 wt%, such as 20 wt% to 40 wt%.

[0096] The coating composition can include a curing agent. Any suitable curing agent can be used. Suitable curing agents are well known to those skilled in the art. The curing agent can include phenolic resins (or phenol-formaldehyde resins); amino resins; epoxy resins; isocyanate resins; β-hydroxy(alkyl)amide resins; alkylated urethane resins; polyacids; acid anhydrides; organometallic acid functional materials; diamines, polyamines; diamides, polyamides, and combinations thereof. The curing agent can include diamines or polyamines.

[0097] The curing agent can be present in the coating composition in any suitable amount. Based on the total solids weight of the coating composition, the curing agent can be present in the coating composition in an amount of 1 wt% to 50 wt%, such as 5 wt% to 30 wt%, such as 5 wt% to 15 wt%.

[0098] The coating composition may optionally contain an additive or a combination of additives. Any suitable additive can be used. Suitable additives are well known to those skilled in the art. Additives can include catalysts; pigments; surfactants; flow control agents; fillers; diluents; organic solvents and combinations thereof.

[0099] Suitable catalysts are well known to those skilled in the art. Catalysts can include phosphoric acid; alkyl aryl sulfonic acids such as dodecylbenzenesulfonic acid; methanesulfonic acid; p-toluenesulfonic acid; dinonylnaphthalenedisulfonic acid; phenylphosphonic acid; tertiary amine hardeners such as 2,4,6-tris(dimethylaminomethyl)phenol and formaldehyde, polymers with N1,N1-dimethyl-1,3-propanediamine and phenol and combinations thereof. When present, the catalyst can be used in any suitable amount in the coating composition. Based on the total solid weight of the coating composition, the catalyst (when present) can be used in an amount of 0.01 wt% to 10 wt%, such as 0.1 wt% to 2 wt%.

[0100] Suitable pigments are well known to those skilled in the art. Pigments can include titanium dioxide or carbon black. When present, the pigment can be used in any suitable amount in the coating composition. Based on the total solid weight of the coating composition, the pigment can be used in the coating composition in an amount of 1 wt% to 30 wt%, such as 1 wt% to 20 wt% or even 1 wt% to 10 wt%.

[0101] Suitable fillers are well known to those skilled in the art. Fillers can include talc or barium sulfate. When present, the filler can be used in any suitable amount in the coating composition. Based on the total solid weight of the coating composition, the coating composition can include 1 wt% to 85 wt%, such as 30 wt% to 80 wt%, or even 60 wt% to 75 wt% of the filler (when present).

[0102] Any suitable organic solvent can be used. Organic solvents can include: aliphatic hydrocarbons such as mineral spirits and high flash naphtha; aromatic hydrocarbons such as benzene; toluene; xylene; solvent naphtha 100, 150, 200; those available from Exxon-Mobil Chemical Company under the trade name SOLVESSO(RTM); alcohols such as ethanol; n-propanol; isopropanol; n-butanol; pentanol; amyl alcohol; 1-methoxy-2-propanol; and butoxyethanol; ketones such as acetone; cyclohexanone; methyl isobutyl ketone; methyl ethyl ketone; esters such as ethyl acetate; butyl acetate; n-hexyl acetate; RHODIASOLV(RTM) RPDE (a blend of succinate and adipate commercially available from Rhodia); glycols such as butanediol; glycol ethers such as methoxypropanol; ethylene glycol monomethyl ether; ethylene glycol monobutyl ether; those available from Dow under the trade name DOWANOL(RTM) such as DOWANOL PM, DOWANOL DPM and DOWANOL PPH; and combinations thereof.

[0103] The coating composition can include any suitable amount of solvent. Based on the total weight of the coating composition, the coating composition can include 1 wt% to 50 wt%, such as 2 wt% to 40 wt%, such as 5 wt% to 30 wt%, such as 5 wt% to 20 wt%, such as 5 wt% to 15 wt% or even 10 wt% of solvent. Alternatively, the coating composition can be solvent-free.

[0104] The coating composition can be prepared as a two-component (2K) composition. Such compositions can be prepared immediately before coating a substrate with the composition. The two-component composition can be prepared by mixing a first component comprising a binder resin and a second component comprising a curing agent. The binder resin and the curing agent can be as defined above. A rheology modifier comprising at least 85 wt% of a compound having a melting temperature greater than 95 °C can be present in the first component and / or the second component. As described above, optional additives can also be present in the first component and / or the second component.

[0105] The coating composition can be substantially free of castor oil and hydrogenated castor oil. The coating composition can be completely free of castor oil and hydrogenated castor oil. The coating composition can be substantially free of vegetable oil and hydrogenated vegetable oil. The coating composition can be completely free of vegetable oil and hydrogenated vegetable oil.

[0106] The coating composition may include a commercial coating composition formulated with the rheology modifier of the present invention. The commercial coating composition may include NovaGuard 840, NovaGuard 890, NovaGuard 260, SigmaLine 2000, PhenGuard(RTM)930 / 935 / 940, PhenGuard(RTM)965 and / or Amercoat(RTM)253 obtained from PPG Industries.

[0107] The present invention can provide a coating composition, which comprises:

[0108] an adhesive resin, which comprises an epoxy phenolic resin;

[0109] a curing agent, which comprises a diamine or a polyamine; and

[0110] a rheology modifier, which comprises a diamide having a melting temperature greater than 95 °C in an amount of at least 85 wt% based on the total weight of the rheology modifier.

[0111] The present invention also provides a substrate, wherein at least a part of the substrate is coated with a coating formed by applying the coating composition described herein to the substrate.

[0112] The present invention also provides a method for producing a substrate, wherein at least a part of the substrate is coated with a coating, and the method comprises the following steps:

[0113] (a) providing the coating composition described herein; and

[0114] (b) applying the composition to at least a part of the substrate to form a coating.

[0115] Suitable features of the substrate and the method are described below.

[0116] The coating composition can be applied to the substrate using any known suitable application method. The application method may include spraying, brushing and / or rolling.

[0117] The coating may include a single coating of the coating composition. Alternatively, the coating may include two or more coatings of the coating composition. The coating may include 2 or 3 coatings of the coating composition. Each coating of the coating composition may be the same or different types of coating composition.

[0118] The coating can have any suitable thickness. The dry film thickness of the coating can be from 200 μm to 2000 μm, such as from 250 μm to 1000 μm, such as from 300 μm to 500 μm. When forming the coating by applying a solvent-based coating composition, the dry film thickness of the coating can be from 200 μm to 1000 μm, such as from 250 μm to 600 μm, such as from 300 μm to 500 μm.

[0119] The substrate can be any suitable substrate, such as a metal substrate and / or a concrete substrate. The metal substrate can include steel; cast iron; metal alloys, such as alloys of aluminum or steel; non-ferrous metals, such as brass, bronze, and copper and combinations thereof. The substrate can include a steel substrate.

[0120] The substrate can be a storage tank or a pipeline having an inner surface, and at least a portion of the inner surface is coated with a coating. The inner surface can include an inner steel surface. The storage tank or pipeline can be any storage tank or pipeline suitable for the chemical storage and transportation industry.

[0121] The substrate can include a steel substrate, such as a storage tank or a pipeline including an inner steel surface.

[0122] The present invention can provide a storage tank or a pipeline, wherein at least a portion of the inner surface of the storage tank or pipeline is coated with a coating formed by applying the coating composition described herein to the substrate.

[0123] The substrate of the present invention can be a storage tank or a pipeline having an inner steel surface, wherein at least a portion of the inner surface is coated with a coating formed by applying the coating composition described herein to the inner surface.

[0124] The present invention can provide a method for producing a storage tank or a pipeline having an inner steel surface, wherein at least a portion of the inner surface is coated with a coating, and the method includes the following steps:

[0125] (a) Providing a coating composition as described herein; and

[0126] (b) Applying the composition to at least a portion of the inner steel surface of the storage tank or pipeline to form a coating.

[0127] The coated inner surface of the storage tank or pipeline can define an inner space. The inner space can contain chemicals, such as organic solvents (such as alcohols, such as methanol) or fatty acids (such as PFAD). The coating has chemical resistance to the chemicals.

[0128] The steel surface can include any suitable type of steel for storage tank and pipeline structures. The steel can include hot-rolled or cold-rolled low-carbon steel. A commercially available steel is Ympress (RTM) Laser E250C obtained from Tata Steel.

[0129] The steel surface can be of any quality. At least a portion of the quality of the steel surface can be rated as Sa 1, Sa 2, Sa 2 1 / 2 or Sa 3 (according to ISO standard 8501-1:2007(E)).

[0130] Prior to applying the coating composition, the surface roughness of the steel surface can be from 20 μm to 150 μm, such as from 40 μm to 100 μm. The Rz value of the steel surface can be from 50 μm to 75 μm, and the peak count can be from 15 counts / cm to 20 counts / cm (Psc value), as measured by a Mitutoyo surface roughness tester SJ-201P.

[0131] The steel surface can include sandblasted steel.

[0132] The present invention also provides a method for enhancing (or increasing) the chemical resistance of a coating on a substrate, the method comprising providing a coating composition comprising a rheology modifier, the rheology modifier comprising at least 85 wt% of a compound having a melting temperature greater than 95 °C, and applying the coating composition to at least a portion of the substrate to provide the coating. The features of the method are as described above for the use of the present invention.

[0133] Unless specifically stated otherwise, the singular includes the plural and the plural encompasses the singular. For example, the use of the singular, i.e., "a" or "an", includes "one or more". Additionally, as used herein, unless specifically stated otherwise, the use of "or" means "and / or", even though "and / or" may be explicitly used in some instances.

[0134] As used herein, unless otherwise expressly stated, all numbers such as those representing values, ranges, amounts, or percentages, even if the term does not explicitly appear, can be construed as beginning with the word "about". Moreover, all numerical ranges recited herein are intended to include all sub-ranges recited herein. When a range is given, any endpoints and / or numbers within those ranges can be combined within the scope of the present invention. The terms "comprising" and the like mean "including but not limited to".

[0135] Throughout this specification, the term "comprising" or "comprises" means including one or more specified components but not excluding the presence of other components. The term "consisting essentially of" or "consists essentially of" means including the specified components but not including other components except for materials present as impurities, inevitable materials present as the processing result for providing the components, and components added for purposes other than achieving the technical effects of the present invention. When referring to a composition, a composition consisting essentially of a group of components may include less than 5 wt%, such as less than 3 wt%, such as less than 1 wt% of non-specified components.

[0136] The term "consisting of" or "consists of" means including the specified components but not including the addition of other components.

[0137] At any appropriate time, depending on the context, the use of the term "comprises" or "comprising" may also be used to cover or include the meaning of "consists essentially of" or "consisting essentially of", and may be used to include the meaning of "consists of" or "consisting of".

[0138] To avoid ambiguity, when the amount of a component in a composition is described in wt%, this means the weight percentage of the specific component relative to the entire composition mentioned. Thus, "wherein the coating composition comprises less than 0.1 wt% of castor oil" means that less than 0.1 wt% of the coating composition is provided by castor oil.

[0139] The optional features described herein may be used alone or may be used in combination with each other as appropriate, and especially in the combinations described in the appended claims. As appropriate, the optional features of each aspect or exemplary embodiment of the present invention described herein should also be understood to be applicable to any other aspect or exemplary embodiment of the present invention. In other words, those skilled in the art reading this specification should consider that the optional features of each exemplary embodiment of the present invention are interchangeable and combinable between different exemplary embodiments.

[0140] To better understand the present invention and to illustrate how embodiments of the present invention may be achieved, reference will now be made, by way of example, to the following experimental data.

[0141] Example

[0142] Example 1 (comparison)

[0143] The following materials and coating compositions were prepared, applied, and tested as follows:

[0144] As a test substrate, a steel plate that had been sandblasted to Sa 2 1 / 2 and had a roughness Rz = 50 μm to 75 μm (Ympress(RTM) Laser E250C obtained from Tata Steel) was used.

[0145] Coating preparation: A commercially available phenolic epoxy resin / amine-cured solvent-based tank coating system was formulated with a commercially available rheology modifier based on hydrogenated castor oil (i.e., where the rheology modifier comprises at least 80 wt% hydrogenated castor oil). The rheology modifier was incorporated into the coating composition / coating according to the supplier's instructions to achieve optimal activation. Based on the total solids weight of the composition, the rheology modifier was present in the coating composition in an amount of 0.95 wt%.

[0146] Coating application: The coating was mixed according to the instructions on the product data sheet. Using air spraying equipment, the coating was applied to the substrate at 20 °C to 23 °C in two layers with a dry film thickness of 150 μm, with an overcoat interval of 2 days. The coating system was cured at 20 °C to 23 °C for 3 weeks.

[0147] Test medium 1: Testing was carried out in palm fatty acid distillate with the code PFADXB165R obtained from Loders Croklaan in the Netherlands. The palm fatty acid distillate was heated to 70 °C and mixed with 5 wt% water to make the chemical mixture more aggressive towards the epoxy resin-based coating, with the aim of shortening the test duration and observing the differences in the resistance of different coatings within a reasonable time period.

[0148] Test medium 2: Testing was carried out in methanol purchased from Avantor (GPR Rectapur ≥ 99.5%). The methanol was maintained at 40 °C to immerse the test panels.

[0149] Test method: Chemical resistance was tested by immersing the coated test panels individually in test media 1 and 2 for a period of 6 months according to ISO 2812-1:2007. Coating defects such as blistering, swelling, delamination, and loss of adhesion were inspected monthly.

[0150] Evaluation: The time to coating failure was used as a measure of its performance. If the coating remained intact for at least 26 weeks (6 months), the coating was considered acceptable.

[0151] Results:

[0152]

[0153] Example 2

[0154] Coating preparation: A commercially available phenolic epoxy resin / amine-cured solvent-based storage tank coating system was formulated with a commercially available diamide-based rheology modifier. Examples of commercially available diamide-based rheology modifiers are provided herein. Based on the total solids weight of the coating composition, rheology modifiers A, B, D, and E are present in the coating composition in an amount of 0.9 wt%. Based on the total solids weight of the coating composition, rheology modifiers C and F are present in the coating composition in an amount of 1.1 wt%.

[0155] The diamide-based rheology additive is characterized by its melting point (melting point profile). This is done using differential scanning calorimetry. Specimens of the sample were sealed in aluminum hermetic pans with 75 μm laser-drilled pinhole lids and scanned in a TA Instrument Discovery DSC using the following method:

[0156] · Heat from -75 °C to 200 °C at 10 °C per minute

[0157] · Heat from 200 °C to -75 °C at 10 °C per minute

[0158] · Heat from -75 °C to 170 °C at 10 °C per minute

[0159] The DSC was calibrated with indium, tin, and zinc standards and the nominal nitrogen purge rate was 50 mL / min. Peak areas were calculated using a linear baseline. An estimate of the ratio between fractions with different melting points was calculated by dividing by the enthalpy per gram of fraction.

[0160] Coating preparation, coating application, test medium, test method, and evaluation were carried out in the same manner as described in Example 1.

[0161] Results – Test medium 1:

[0162]

[0163]

[0164] The above results show that the melting point of the rheology modifier is an important factor in the resistance of the coating to hot palm fatty acid distillate. When at least 85 wt% of the rheology modifier has a melting point far above the operating and test temperatures of the palm fatty acid distillate, the coating shows long-term resistance. A low percentage (<15 wt%) of components with a lower melting point is acceptable and still provides resistance to the coating. However, when the components with a lower melting point are present in an amount above about 15 wt%, the resistance to palm fatty acid distillate is insufficient.

[0165] Results – Test Medium 2:

[0166]

[0167] The results of Example 2 are summarized below:

[0168]

[0169]

[0170] Attention is directed to all papers and documents that are filed concurrently with or before this specification and in connection with this application and that are hereby publicly disclosed and available for public examination, and the contents of all such papers and documents are hereby incorporated by reference into this text.

[0171] All features (including any appended claims, abstract, and drawings) disclosed in this specification and / or all steps of any method or process so disclosed may be combined in any combination, except combinations where at least some of these features and / or steps are mutually exclusive.

[0172] Each feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by an alternative feature serving the same, equivalent, or similar purpose, unless expressly stated otherwise. Thus, each feature disclosed is only an example of a generic series of equivalent or similar features, unless expressly stated otherwise.

[0173] The invention is not limited to the details of the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification (including any appended claims, abstract, and drawings) or to any novel step or any novel combination of steps of any method or process so disclosed.

[0174] Although specific examples of the invention have been described above for purposes of illustration, it will be apparent to those skilled in the art that many details may be varied without departing from the invention as defined in the appended claims.

Claims

1. Use of a rheological agent in a coating composition, wherein when the coating composition is applied to at least a part of a substrate, the rheological agent is used to enhance the chemical resistance of the coating formed from the coating composition, wherein the rheological agent comprises at least 85 wt% of a compound having a melting temperature greater than 95 °C and containing at least two amide groups, and wherein the rheological agent enhances the chemical resistance of the coating by providing chemical resistance to fatty acids and / or to organic solvents.

2. The use according to claim 1, wherein the chemical resistance is determined according to ISO 2812-1:2007.

3. The use according to claim 1 or claim 2, wherein the rheological agent enhances the chemical resistance of the coating to long-term exposure to chemicals and / or repeated cycles.

4. The use according to claim 3, wherein the rheological agent enhances the chemical resistance of the coating such that the coating remains intact after continuous exposure to chemicals for a total of at least 6 months.

5. The use according to claim 1 or claim 2, wherein the rheological agent enhances the chemical resistance of the coating by providing chemical resistance to fatty acids and to organic solvents.

6. The use according to claim 5, wherein the fatty acid is palm fatty acid distillate (PFAD).

7. The use according to claim 5, wherein the organic solvent is methanol.

8. The use according to claim 1 or claim 2, wherein the rheological agent enhances the chemical resistance of the coating by providing chemical resistance to fatty acids at a temperature of at least 60 °C and providing chemical resistance to organic solvents at a temperature of at least 40 °C.

9. The use according to claim 1 or claim 2, wherein the rheological agent comprises a thixotropic agent.

10. The use according to claim 1 or claim 2, wherein the compound containing at least two amide groups comprises a diamide.

11. The use according to claim 1 or claim 2, wherein the rheological agent is substantially free of castor oil and / or hydrogenated castor oil.

12. The use according to claim 1 or claim 2, wherein the substrate comprises a steel substrate.

13. The use according to claim 12, wherein the steel substrate is a storage tank or pipeline comprising an internal steel surface.

14. A storage tank or pipeline suitable for the chemical storage and transportation industry, wherein at least a part of the internal surface of the storage tank or pipeline is coated with a coating formed by applying a coating composition containing a rheological agent to the internal surface, wherein the rheological agent comprises at least 85 wt% of a compound having a melting temperature greater than 95 °C and containing at least two amide groups.

15. The storage tank or pipeline according to claim 14, wherein the rheological agent comprises a thixotropic agent.

16. The storage tank or pipeline according to claim 14, wherein the compound containing at least two amide groups comprises a diamide.

17. The storage tank or pipeline according to claim 14, wherein the coating composition is substantially free of castor oil and / or hydrogenated castor oil.

18. The storage tank or pipeline according to claim 14, wherein the storage tank or pipeline comprises an internal steel surface.

19. A method of producing a storage tank or pipeline, at least a portion of the internal surface of which is coated with a coating, wherein the storage tank or pipeline is suitable for the chemical storage and transportation industry, the method comprising the steps of: (a) providing a coating composition comprising a rheology modifier, wherein the rheology modifier comprises at least 85 wt% of a compound having a melting temperature greater than 95 °C and comprising at least two amide groups; and (b) applying the coating composition to at least a portion of the internal surface of the storage tank or pipeline to form a coating.

20. The method according to claim 19, wherein the rheology modifier comprises a thixotropic agent.

21. The method according to claim 19, wherein the compound comprising at least two amide groups comprises a diamide.

22. The method according to claim 19, wherein the coating composition is substantially free of castor oil and / or hydrogenated castor oil.

23. The method according to claim 19, wherein the storage tank or pipeline comprises an internal steel surface.

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