Insulating silicone coating composition

Abstract

Disclosed herein is a thermal barrier coating composition comprising: (a) a room temperature vulcanized (RTV) polymer wherein the RTV polymer comprises: (i) a polysiloxane comprising hydroxyl, acetoxy, epoxy, alkoxy, oxime, and / or amine terminal groups; and / or (ii) a set of reactive components that react to form the polysiloxane comprising hydroxyl, acetoxy, epoxy, alkoxy, oxime, and / or amine end groups; (b) a silane-containing adhesion promoter comprising an alkoxy functional group and an epoxide functional group; (c) a heat insulating agent; and (d) a carrier.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 501,806, filed on May 12, 2023, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to thermal barrier silicone coating compositions, coatings formed therefrom, and methods of using such coatings. Background Art

[0004] Coatings for insulating components such as metal pipes typically use water-based acrylic emulsions or epoxy-based adhesives. Such coatings have some limitations, such as the need for multiple coats to achieve the desired film thickness, the need for primers for corrosion control, and the need for seal coats and / or jackets for moisture permeability and UV protection. In addition, under thermal loads at temperatures above 300°F (150°C), such systems typically degrade in approximately 5 to 7 years. Summary of the invention

[0005] Disclosed herein is a thermal barrier coating composition comprising: (a) a room temperature vulcanizing (RTV) polymer, wherein the RTV polymer comprises: (i) a polysiloxane comprising hydroxyl, acetoxy, epoxy, alkoxy, oxime and / or amine end groups; and / or (ii) a set of reactive components that react to form a polysiloxane comprising hydroxyl, acetoxy, epoxy, alkoxy, oxime and / or amine end groups; (b) an adhesion promoter comprising a silane comprising (i) a polymer crosslinking group, such as an acetoxy, alkoxy, oxime or amine group, and (ii) a substrate bonding group, such as an epoxide, hydroxyl, isocyanate, mercapto, phosphonate or ester group; (c) a thermal barrier agent; and (d) a carrier.

[0006] Also disclosed herein is a method of coating a substrate by applying the disclosed coating composition to at least a portion of the substrate. Also disclosed herein is a substrate at least partially coated with the disclosed coating composition.

[0007] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to indicate the scope of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a graph showing the results of a pull-off adhesion test comparing the disclosed thermal barrier coating compositions to a comparative coating composition.

[0009] Figure 2 is a graph showing the results of thermal conductivity testing comparing the disclosed thermal barrier coating compositions to comparative coating compositions.

[0010] Figure 3 is a graph showing the results of coating skin temperature testing comparing the disclosed thermal barrier coating compositions to comparative coating compositions. DETAILED DESCRIPTION

[0011] Coating composition overview

[0012] Disclosed herein is a thermal barrier coating composition comprising: (a) a room temperature vulcanizing (RTV) polymer, wherein the RTV polymer comprises: (i) a polysiloxane comprising hydroxyl, acetoxy, epoxy, alkoxy, oxime and / or amine terminal groups; and / or (ii) a set of reactive components that react to form a polysiloxane comprising hydroxyl, acetoxy, epoxy, alkoxy, oxime and / or amine terminal groups; (b) an adhesion promoter comprising a silane comprising (i) a polymer crosslinking group such as an acetoxy, alkoxy, oxime or amine group, and (ii) a substrate bonding group such as an epoxide, hydroxyl, isocyanate, mercapto, phosphonate or ester group; (c) a thermal barrier agent; and (d) a carrier. Also disclosed herein is a method of coating a substrate by applying the disclosed coating composition to at least a portion of the substrate. Also disclosed herein is a substrate at least partially coated with the disclosed coating composition.

[0013] For example, the thermal insulation coating compositions described herein can achieve effective bonding, effective heat insulation and / or effective corrosion protection to the substrate to which it is applied. The disclosed thermal insulation coating compositions can be applied to the substrate with a suitable film thickness (e.g., 100 mils to 1000 mils, typically up to 500 mils) by a single or multiple applied coatings. The thermal insulation coating compositions can be sprayable compositions. The term "sprayable" refers to the coating composition being applied to the substrate using conventional spraying equipment (e.g., texture air sprayers or high volume, low pressure (HVLP) air sprayers) for the coating composition.

[0014] The thermal barrier coating composition may comprise a two-part system. For example, the RTV polymer and the adhesion promoter may be included in the first part of the two-part system, and the catalyst is included in the second part of the two-part system.

[0015] RTV polymer

[0016] RTV polymer refers to a curable polysiloxane that can be cured at room temperature (eg, 20° C. to 25° C.) in the presence of moisture and / or a catalyst. RTV polymers can be cured at room temperature or other suitable temperatures such as in the range of 5° C. to 38° C.

[0017] The RTV polymer may be a polysiloxane comprising hydroxyl, acetoxy, alkoxy, oxime and / or amine terminal groups. Suitable RTV polymers may have formula (I):

[0018]

[0019] In formula I, each R1 can independently be H or an alkyl group (e.g., C1 to C6 alkyl), such as wherein each R1 is methyl, so that the polysiloxane of formula I is dimethylpolysiloxane. Each R2 can be H or an alkyl group (e.g., C1 to C6 alkyl). Each X end group can independently be a hydroxyl, acetoxy, epoxy, alkoxy, oxime or amine. The X end groups can be the same or different.

[0020] In Formula I, n can be selected so that the RTV polymer has an average molecular weight of 10,000 to 150,000, such as 50,000 to 140,000, or 75,000 to 130,000, or 100,000 to 125,000, or a range where the endpoints are selected from any combination of the foregoing values. All molecular weights (Mw) disclosed herein can be determined by calibration with polystyrene standards using gel permeation chromatography. Suitable RTV polymers include commercially available RTV polymers such as ELASTOSIL E951 and ELASTOSIL M4444 (Wacker Chemical Corporation, Adrian, MI).

[0021] The RTV polymer can be further cured and / or crosslinked using water available in the ambient atmosphere and / or within the coating composition. Water hydrolyzes the hydrolyzable end groups on the polysiloxane, generating free hydroxyl groups available for condensation reactions, thereby further curing and / or crosslinking the RTV polymer.

[0022] RTV polymers can be formed from a multi-part system comprising an adhesive portion and a crosslinking portion. For example, RTV polymers can be formed from a group of components comprising a hydroxyl-terminated polysiloxane (e.g., a hydroxyl-terminated dimethyl polysiloxane) and a functional silane (e.g., a silane comprising a hydrolyzable group such as an acetoxy, epoxy, alkoxy, oxime, or amine). For example, RTV polymers can be formed from a group of reactive components comprising a hydroxyl-terminated polysiloxane of Formula II and a functional silane of Formula III:

[0023]

[0024] In Formula II, each R1 can independently be H or an alkyl group (e.g., a C1 to C6 alkyl group). In Formula III, each X can independently be an acetoxy group, an epoxy group, an alkoxy group, an oxime group, or an amine group, and R2 can be H or an alkyl group (e.g., a C1 to C6 alkyl group). The X terminal groups can be the same or different. In Formula II, n can be selected to provide a polysiloxane of a desired molecular weight.

[0025] The set of components that form the RTV polymer may also include fillers such as silica (ie, SiO2), silanes, and / or silylamines (eg, trialkylsilylamines such as bis(trimethylsilyl)amine).

[0026] The thermal barrier coating composition may include an RTV polymer, such as shown in Formula I, and / or a set of reactive components for forming an RTV polymer, such as shown in Formulas II and III. As used herein, the term RTV polymer may refer to a functionalized polysiloxane such as in Formula I, or to a set of reactive components such as shown in Formulas II and III.

[0027] The RTV polymer can be included in a concentration of up to 50 wt %, up to 40 wt %, or up to 30 wt %, such as 3 wt % to 25 wt %, 4 wt % to 20 wt %, 5 wt % to 15 wt %, or 5 wt % to 10 wt %, or a range with endpoints selected from any combination of the foregoing values, based on the total weight of the coating composition.

[0028] The thermal barrier coating composition may be substantially free of or completely free of polysiloxane resins other than the RTV polymer. For example, the thermal barrier coating composition may be free of alkoxy-functional polysiloxane resins (such as methoxy-functional polysiloxane resins) other than the RTV polymer.

[0029] Adhesion promoter

[0030] The adhesion promoter may include a silane, and the adhesion promoter may include a polymer crosslinking group and a substrate bonding group. The polymer crosslinking group may include an alkoxy, acetoxy, oxime or amine group. The substrate bonding group may include an epoxide (i.e., an epoxy group or an oxirane group), a hydroxyl, an isocyanate (i.e., -N=C=O), a thiol (i.e., -SH), a phosphonate or ester group. The epoxide group may include a glycidyloxy group, such as a glycidyloxyalkyl group, such as a glycidyloxypropyl group.

[0031] As used herein, an epoxide group refers to a A glycidyl group refers to a group having the formula and a glycidyloxy group refers to a group having the formula The group.

[0032] The adhesion promoter may include multiple (such as, two or three) crosslinking groups, such as multiple (such as, two or three) alkoxy groups. The alkoxy groups may independently be C1 to C6 alkoxy groups (eg, methoxy, ethoxy, etc.).

[0033] The adhesion promoter may include (3-glycidyloxypropyl)trimethoxysilane, such as shown in Formula IV:

[0034]

[0035] Suitable adhesion promoters include the silane products commercially available under the name GENIOSIL GP™ (Wacker Chemical Corporation, Adrian, MI).

[0036] The adhesion promoter may be included in a concentration ranging from 0.5 wt % to 8 wt %, such as from 1 wt % to 4 wt %, or any combination of the foregoing values ​​as endpoints, based on the total weight of the coating composition.

[0037] Dehumidifier

[0038] The coating composition may include a dehumidifier. The dehumidifier may include (i) a vinyl group and / or a phenyl group, and (ii) an alkoxy group (e.g., a C1 to C6 alkoxy group, such as a methoxy group, an ethoxy group, etc.). For example, the dehumidifier may include vinyl trimethoxy silane and / or phenyl trimethoxy silane. Suitable dehumidifiers include silane products commercially available under the name GENIOSIL XL-10 (Wacker Chemical Corporation, Adrian, MI).

[0039] The dehumidifier may be included at a concentration ranging from 0.5 wt % to 8 wt %, such as from 1 wt % to 4 wt %, or any combination of the foregoing values ​​as endpoints, based on the total weight of the coating composition.

[0040] catalyst

[0041] The thermal insulation coating composition may also include a catalyst. The catalyst may include a tin-based and / or titanate-based catalyst. The titanate catalyst may include an alkoxy titanate, such as tert-butyl titanate, such as commercially available under the name TYZOR TNBT (Dorf Ketal, Houston, TX). The tin-based catalyst may include (i) an alkyl group, such as a C1 to C6 alkyl group, such as a butyl group, and / or (ii) an acetoxy group. For example, the tin-based catalyst may include dibutyltin diacetate, such as commercially available under the name FASCAT 4200 (PMC Organometallix, Carrollton, KY).

[0042] The total amount of catalyst may be included in a concentration ranging from 0.5 wt % to 5 wt %, such as 0.75 wt % to 3 wt %, or 1 wt % to 2.5 wt %, or any combination of the foregoing values ​​as endpoints, based on the total weight of the coating composition.

[0043] When the coating composition comprises a two-part system, the RTV polymer and / or adhesion promoter may be included in the first part (ie, Part A) of the two-part system, while the catalyst is included in the second part (ie, Part B) of the two-part system.

[0044] Heat Insulation

[0045] The term "thermal barrier" refers to a component that enhances the thermal insulation properties of a coating when applied to a substrate. For example, when the coating composition is applied to a heated metal substrate (such as a metal pipe through which a fluid flows at an elevated temperature), the coating composition provides thermal insulation from the heated metal substrate.

[0046] The thermal insulator may include microspheres, such as hollow microspheres comprising glass, borosilicate, aluminum silicate, ceramic, and / or polymeric materials. Hollow microspheres may exhibit thermal insulating properties by virtue of the volume of air or gas contained therein. Suitable microspheres include a microsphere product commercially available under the name Q-CEL 7040S (Potters Industries, Malvern, PA).

[0047] Certain thermal insulators (e.g., microspheres) may also be used as passivating agents. Suitable thermal insulators that also act as passivating agents include sodium silicate. The term passivation refers to the ability to exhibit corrosion resistance, such as by forming a non-reactive or passivating portion on the substrate. When thermal insulators that do not act as passivating agents are used, auxiliary passivating agents may be included, such as magnesium oxide, zinc phosphate, metal-modified zinc phosphate, metal-modified phosphosilicates, and / or metal-modified borosilicates, wherein the metals include calcium, barium, strontium, molybdenum, magnesium, and / or aluminum.

[0048] The coating composition may also include mineral fibers. Suitable mineral fibers include those sold under the trade name LAPINUS MS603 (Lapinus Fibres BV, Roermond, NL).

[0049] The thermal barrier agent may be included at a concentration ranging from 5 wt % to 40 wt %, such as 7.5 wt % to 25 wt %, or 10 wt % to 20 wt %, or using any combination of the foregoing values ​​as endpoints, based on the total weight of the coating composition.

[0050] Carrier

[0051] The RTV polymer, adhesion promoter and / or other resin components of the coating composition can be dissolved in the carrier or can be suspended in the carrier. For example, the coating composition can be a solution in which the RTV polymer (and / or other resin components) is dissolved, or can be a dispersion in which the RTV polymer (and / or other resin components) is suspended.

[0052] The carrier may include a solvent such as a ketone (e.g., acetone), an alcohol, an aliphatic hydrocarbon, an aromatic hydrocarbon, an ester, an ether, and / or a halogenated hydrocarbon. Suitable solvents include, for example, acetone, methyl ethyl ketone (i.e., butanone), methyl amyl ketone (i.e., 2-heptanone), xylene, toluene, mineral spirits, methyl acetate, cyclohexane, dimethyl carbonate, p-chlorotrifluorotoluene, and combinations thereof. The carrier may include water.

[0053] The carrier may be included in a range of 40 wt % to 80 wt %, such as 50 wt % to 70 wt %, based on the total weight of the coating composition, or using any combination of the foregoing values ​​as endpoints.

[0054] Other coating composition components

[0055] The thermal insulation coating composition may include other components such as fillers, rheology modifiers (e.g., bentonite clay derivatives), coalescing agents, dispersants, defoamers, pH adjusters, matting agents, biocides, bactericides, dehumidifiers (e.g., alkoxysilanes, such as phenyltrialkoxysilanes, such as phenyltrimethoxysilane), pigments, aggregates, plasticizers, additional adhesion promoters, suspending agents, thixotropic agents, fillers (e.g., mineral wool, wollastonite, rock wool insulation, graphite, alumina, potassium titanate), catalyst chelating agents, pigment wetting agents, asphaltene and asphalt fillers, anti-settling agents, diluents, UV light stabilizers, degassing agents, surfactants, other coating composition components known in the art, or combinations thereof.

[0056] The thermal barrier coating composition may contain up to 10 wt % of such components, based on the total weight of the coating composition.

[0057] Exemplary functional properties

[0058] The thermal insulation coating composition can advantageously exhibit effective bonding and thermal insulation functions when cured. For example, the disclosed thermal insulation coating composition, when cured, exhibits a pull-off adhesion strength of 50 psi or greater (e.g., 100 psi, 150 psi, 200 psi, 250 psi, 300 psi, 350 psi, 400 psi, or a range using any combination of the foregoing values ​​as endpoints) after curing at room temperature according to ASTM D4541-22, and / or exhibits a pull-off adhesion strength of 50 psi or greater (e.g., 100 psi, 150 psi, 200 psi, 250 psi, 300 psi, 350 psi, 400 psi, or a range using any combination of the foregoing values ​​as endpoints) after exposure at 260° C. for 100 hours according to ASTM D4541-22.

[0059] The disclosed thermal barrier coating composition, when cured, may exhibit a thermal conductivity of 0.12 W / m*K or less (eg, as low as 0.10 W / m*K) when measured at 50° C. according to ASTM 7984-16.

[0060] The disclosed thermal insulation coating compositions, when applied to a substrate (e.g., a metal pipe) and cured on the substrate, exhibit corrosion protection that is better than or substantially similar to the corrosion protection provided by an insulation system comprising (i) a spray-applied insulation primer, (ii) a mechanical insulation portion, and (iii) a jacket. Such conventional insulation systems typically include an initial layer of primer, followed by application of a mechanical insulation portion to a desired thickness, followed by application of a seal coat and / or a jacket (usually metal) to protect the insulation layer from moisture, UV light, and other external factors. The disclosed thermal insulation coating compositions can advantageously perform as well or better than such conventional insulation systems without requiring the same complexity in terms of the number of components and application steps.

[0061] Exemplary Usage

[0062] The disclosed thermal barrier coating compositions can be applied to a substrate by single or multiple coats at a suitable film thickness (e.g., 100 mils to 1000 mils, typically up to 500 mils). The thermal barrier coating composition can be a sprayable composition. The term "sprayable" means that the coating composition can be applied to a substrate using conventional spraying equipment for coating compositions.

[0063] The substrate may include, for example, metals and / or other materials that may degrade due to blistering, cracking, adhesion failure, and / or corrosion. Metal substrates suitable for use with the disclosed coating compositions include ferrous and nonferrous metals such as tin, aluminum, steel (e.g., stainless steel, tin-plated steel, chrome-passivated steel, galvanized steel, coiled strip steel), other coiled metals, zinc, aluminum, nickel, copper, magnesium, silver, gold, other metals, and alloys and mixtures thereof.

[0064] Such substrates may form at least a portion of a component of an industrial device. Non-limiting examples include reactors, exhaust stacks, reformers, distillation columns, pipelines, valves, heat exchangers, boilers, and / or containers (e.g., storage tanks for materials such as industrial liquids, hydrocarbon fuels, and liquid natural gas). Such equipment may be used in a variety of industries, such as food processing, pulp and paper production, and agricultural related power generation.

[0065] Other substrates to which the disclosed coating compositions may be applied include glass; glass fibers; carbon fiber composites; basalt fiber composites; siloxane and ceramic fibers; ceramics such as silicon nitride, silicon carbide, silicon dioxide, aluminum oxide, zirconium oxide, and the like; plastics such as polymethyl methacrylate, polyurethane, polycarbonate, polyester (including polyethylene terephthalate), polyimide, polyamide, epoxy, ABS polymers, polyethylene, polypropylene, polyoxymethylene; porous mineral materials such as concrete, clay bricks, marble, basalt, asphalt, loam, terracotta; organic materials such as wood, leather, parchment, paper, and textiles; and coating surfaces such as plastic latex paints, acrylic coatings, epoxy coatings, melamine resins, polyurethane resins, and alkyd coatings. The substrate may include multiple layers of material and / or multiple surfaces formed of different materials.

[0066] Additional Terms and Definitions

[0067] As used herein, the term "polymer" refers broadly to prepolymers, oligomers, and both homopolymers and copolymers. The terms "resin" and "polymer" are used interchangeably.

[0068] Although specific examples of coating compositions are described herein, these examples do not limit the scope of the present disclosure.For example, when a specific ethylenically unsaturated monomer is described by way of example, it should be understood that other ethylenically unsaturated monomers may additionally or alternatively be used.

[0069] Plural use of a term encompasses singular use of the term and vice versa. For example, although the disclosed coating compositions have been described as including "a" thermal barrier and "an" RTV polymer, additional thermal barriers and / or RTV polymers may be included.

[0070] Any numerical range recited herein is intended to include all subranges subsumed therein. When ranges are given, any endpoints within those ranges and / or numbers within those ranges can be combined within the scope of the present disclosure.

[0071] Unless otherwise indicated, numbers used in the specification and claims expressing quantities, ratios, percentages or other measurements should be understood as being modified by the term "about" or its synonyms, even if the term does not explicitly appear. Alternatively, numbers can be modified by explicitly using the term "exactly" to clarify specific situations where the term "about" does not apply.

[0072] When the term "about" or its synonyms (e.g., "approximately," "substantially," "essentially," etc.) is used in conjunction with a specified amount, value, or condition, it can be understood as an amount, value, or condition that deviates from the specified amount, value, or condition by 10% or less, 5% or less, 1% or less, 0.1% or less, or 0.01% or less. For example, a concentration of "about" X wt% includes values ​​that differ (higher or lower) from X by up to 10%, up to 5%, up to 1%, up to 0.1%, or up to 0.01%. For example, a concentration of "about" 50 wt% is synonymous with a range of 45 wt% to 55 wt%, or 47.5 wt% to 52.5 wt%, or 49.5 wt% to 50.5 wt%, etc.

[0073] "Comprising" and similar terms mean "including but not limited to". Similarly, as used herein, the terms "on", "applied on / over", "formed on / over", "deposited on / over", "covering", and "provided on / over" a surface mean applied, formed, deposited, covered, or provided on the surface, respectively, but not necessarily in contact with the surface. For example, a coating "formed on" a substrate does not exclude the presence of one or more other coatings of the same or different composition located between the formed coating and the substrate.

[0074] The thermal insulation silicone coating compositions disclosed herein should be understood to include / comprise one or more of the disclosed components, and thus may include additional components not specifically described. Alternatively, the thermal insulation silicone coating composition may be described as "essentially consisting of" or "consisting of" one or more of the disclosed components. As used herein, a coating composition "essentially consisting of" a group of listed components means that the coating composition may further include unlisted components, as long as these unlisted components do not substantially affect the functional properties of the coating composition (e.g., adhesion and thermal insulation functions).

[0075] Any individual component of the thermal insulating silicone coating composition explicitly disclosed herein may optionally be omitted. In addition, the coating composition disclosed herein is optionally substantially free of or completely free of components not specifically described. That is, undisclosed components may optionally be substantially omitted or completely omitted from the disclosed thermal insulating silicone coating composition. For example, a specific silane additive or polysiloxane component that is not specifically described as being included in the disclosed thermal insulating silicone coating composition may optionally be excluded (i.e., substantially omitted or completely omitted).

[0076] A composition that "substantially omits" or is "substantially free" of a component may include trace and / or non-functional amounts of the component. For example, the "substantially omitted" component may be included in an amount of no more than 2.5%, no more than 2%, no more than 1.5%, no more than 1%, no more than 0.1%, or no more than 0.01% by weight of the total weight of the composition or by the total weight of the monomers of the composition.

[0077] A composition that "completely omits" or is "completely free of" a component does not include a detectable amount of that component (i.e., does not include an amount above any inherent background signal associated with the testing instrument) when analyzed using standard coating composition analysis techniques such as chromatographic techniques (e.g., thin layer chromatography (TLC), gas chromatography (GC), liquid chromatography (LC)) or spectroscopic techniques (e.g., Fourier transform infrared (FTIR) spectroscopy).

[0078] Any headings and sub-headings used herein are for organizational purposes only and are not meant to limit the scope of the description or the claims.

[0079] Examples

[0080] Example 1

[0081] A two-part coating composition (including Part A and Part B) was prepared according to the components listed in Table 1 .

[0082] Table 1

[0083]

[0084] *RTV silicone system based on hydroxyl functional polysiloxane and acetoxy functional silane is commercially available as ELASTOSILE 951.

[0085] **Other coating composition components disclosed herein and conventional in the art.

[0086]

[0087]

[0088] *Other coating composition components disclosed herein and conventional in the art.

[0089] Example 2

[0090] A two-part coating composition was prepared according to the components listed in Table 2 (including Part A and Part B).

[0091] Table 2

[0092]

[0093] *RTV silicone system based on hydroxyl functional polysiloxane and acetoxy functional silane is commercially available as ELASTOSILE 951.

[0094] **Other coating composition components disclosed herein and conventional in the art.

[0095]

[0096] *Other coating composition components disclosed herein and conventional in the art.

[0097] Thus, the coating composition of Example 2 is similar to the coating composition of Example 1, except that the amount of the adhesion promoter containing alkoxy and epoxide functional groups and the RTV silicone polymer included in Part A is slightly reduced.

[0098] Example 3

[0099] A two-part coating composition was prepared according to the components listed in Table 3 (including Part A and Part B).

[0100] Table 3

[0101]

[0102] *RTV silicone system based on hydroxyl functional polysiloxane and acetoxy functional silane is commercially available as ELASTOSILE 951.

[0103] **Methoxy functional polysiloxane sold under the trade name DOWSIL 2405 (Dow Chemical Company, Midland, MI).

[0104] ***Other coating composition components disclosed herein and conventional in the art.

[0105]

[0106] *Other coating composition components disclosed herein and conventional in the art.

[0107] Thus, the coating composition of Example 3 is similar to the coating composition of Example 1, except that the additional alkoxy polysiloxane resin is included in Part A and the amount of RTV silicone polymer is slightly reduced. The coating composition of Example 3 is also similar to the coating composition of Example 2, except that the composition of Example 3 replaces the adhesion promoter containing alkoxy and epoxide functional groups with the additional alkoxy polysiloxane resin.

[0108] Adhesion test

[0109] Each of the coating compositions of Examples 1 to 3 was applied to a 100 mm x 150 mm x 3.175 mm thick steel plate (sandblasted, 75 to 100 micron profile, degreased) with a dry film thickness of 5 mm by knife coating. The coated plate was dried for 7 days under ambient conditions. According to ASTM D4541-22, a pull-off adhesion tester (DeFelsko PosiTestAT-M) with a 20 mm pulley was used to measure the pull-off adhesion of the coating from the metal substrate. Subsequently, the tested plate was exposed to a temperature of 260° C. on a hot plate for 100 hours. If necessary, cracking, delamination or blistering during heating can be observed. According to ASTM D4541, the pull-off adhesion of the heat exposed coating was measured again using the same tester.

[0110] The results of the adhesion test are shown in Figure 1 As shown, the coating composition of Example 2 exhibited the best performance. The coating composition of Example 2 exhibited the highest adhesion when ambient cured, and exhibited the highest adhesion after thermal exposure together with the coating composition of Example 3. The results of the adhesion test are also shown in Table 4.

[0111] Table 4: Pull-off Adhesion Results (psi)

[0112] Coating composition Curing at room temperature damage 260℃ / 100 hours exposure damage Example 1 151 Bonding 192 Adhesive Example 2 250 Adhesive 300 Adhesive Example 3 224 Adhesive 300 Adhesive

[0113] Thermal conductivity test

[0114] Each of the coating compositions of Examples 1 to 3 was prepared by drying the wet material in an aluminum pan at ambient conditions for 7 days. Samples of 70 mm x 70 mm x 10 mm in size were cut from the dried samples and smoothed with 200 grit sandpaper. The thermal conductivity of these samples was measured at 50° C. using a modified transient plane heat source method (MTPS) Trident C-Therm instrument according to ASTM 7984-16.

[0115] Thermal conductivity test results are as follows Figure 2 As shown in the figure, the coating composition of Example 2 exhibits the best performance. The coating composition of Example 2 exhibits the lowest thermal conductivity, followed by the coating composition of Example 3, and then the coating composition of Example 1, which exhibits the highest thermal conductivity. The results of the thermal conductivity test are also shown in Table 5.

[0116] Table 5: Thermal conductivity results

[0117]

[0118] Coating surface temperature

[0119] Each of the coating compositions of Examples 1 to 3 was applied to 100 mm x 150 mm x 3.175 mm thick steel panels (sandblasted, 375 to 100 micron profile, degreased) by knife coating at a dry film thickness of 5 mm. The coated panels were allowed to dry for 7 days under ambient conditions. Afterwards, the test panels were heated on a hot plate at the desired test temperature and the skin temperature of the coating was measured by a Peakmeter thermometer using a K-type thermocouple sensor probe.

[0120] The coating surface temperature test results are as follows: Figure 3 As shown, the results of the tested coating compositions are comparable, with the coating composition of Example 2 exhibiting a slightly lower coating surface temperature at the higher use temperature tested. The coating surface temperature test results are also shown in Table 6.

[0121] Table 6: Coating surface temperature at 5mm thickness (℃)

[0122] Coating composition Operating temperature: 149°C Operating temperature: 204°C Operating temperature: 260°C Example 1 92 127 157 Example 2 92 124 155 Example 3 91 127 156

[0123] Acoustic testing

[0124] Acoustic Insertion Loss performance is measured using custom test equipment using square samples measuring 13" x 13". The test and method are in accordance with ISO 9614 and ASTM E2249. Acoustic Insertion Loss in this application is defined as the difference between the sound pressure levels measured on a reference sample and a specific test sample. A test board element mounted between these two areas with a high insertion loss value indicates effective acoustic isolation and vice versa.

[0125] The test apparatus consists of an aluminum rectangular enclosure with a noise source mounted on one end and a test panel mounted on the other end. The noise source is a tube with a speaker at one end and an opening at the other end. The noise generated by the speaker radiates through the tube and into one end of the rectangular enclosure. The other end of the rectangular enclosure accommodates the installation and removal of a square test sample with a length dimension of 13 inches x 13 inches. The edges of the sample are acoustically sealed within 1 inch of the square perimeter, leaving an open area of ​​12 inches x 12 inches exposed to the noise.

[0126] Insertion loss is measured by generating a high broadband noise inside the enclosure, measuring its reference sound pressure level with a microphone mounted inside the enclosure, and then comparing it with the sound pressure level measured outside the enclosure using a sound intensity probe. Since the external sound intensity probe can be moved in the X and Y axes, it is also possible to plot the sound pressure level over the central area of ​​a square sample. The entire setup is placed in an anechoic chamber (room temperature) to minimize the effects of other potential acoustic interferences.

[0127] The speaker tube kit generates random noise up to 25.6kHz at a constant level. The sound intensity probe includes a pair of microphones located 2 inches from the board and the frequency is set to 50Hz to 12.5kHz in 1 / 3 octave bands with an averaging time of 16 seconds at each point. The measurement data includes the sound pressure level (SPL) in dB(A) with a standard reference pressure of 20μPa. The reduction in overall sound pressure level through the central sub-area of ​​the sample can be summed over all 1 / 3 octave bands between 125Hz and 8kHz. Lower SPL values ​​indicate better sound insulation.

[0128] Test panels coated with a thermally insulating silicone coating composition disclosed herein, such as the Example 2 coating composition, are expected to exhibit acoustic insertion losses that produce an SPL of 70 to 85 dB(A).

Claims

1. A thermal insulation coating composition comprising: (a) a room temperature vulcanizing (RTV) polymer comprising (i) polysiloxanes comprising hydroxyl, acetoxy, epoxy, alkoxy, oxime and / or amine terminal groups, and / or (ii) a set of reactive components which react to form said polysiloxane comprising hydroxyl, acetoxy, epoxy, alkoxy, oxime and / or amine end groups; (b) a silane-containing adhesion promoter comprising (i) polymer crosslinking groups, such as acetoxy, alkoxy, oxime or amine groups, and (ii) substrate bonding groups such as epoxide, hydroxyl, isocyanate, mercapto, phosphonate or ester groups; (c) thermal insulation agents; and (d) Carrier.

2. The coating composition of claim 1, wherein the polysiloxane of the RTV polymer is a dialkyl polysiloxane, such as a dialkyl polysiloxane wherein each alkyl group is independently a C1 to C6 alkyl group, such as dimethyl polysiloxane.

3. A coating composition according to any preceding claim, wherein the polysiloxane of the RTV polymer has an average molecular weight of 10,000 to 150,000, such as 50,000 to 140,000, such as 75,000 to 130,000, such as 100,000 to 125,000.

4. A coating composition according to any preceding claim, wherein the RTV polymer is included in a concentration of up to 50 wt %, up to 40 wt %, or up to 30 wt %, such as 3 wt % to 25 wt %, 4 wt % to 20 wt %, 5 wt % to 15 wt %, or 5 wt % to 10 wt %, based on the total weight of the coating composition.

5. A coating composition according to any preceding claim, wherein: The substrate bonding group of the adhesion promoter comprises a glycidyloxy group, such as a glycidyloxyalkyl group, such as a glycidyloxypropyl group; and / or The polymer cross-linking groups of the adhesion promoter include methoxy groups.

6. A coating composition according to any preceding claim, wherein the adhesion promoter comprises a plurality of alkoxy groups.

7. A coating composition according to any preceding claim, wherein the adhesion promoter comprises (3-glycidyloxypropyl)trimethoxysilane.

8. The coating composition according to any preceding claim, further comprising a desiccant, wherein the desiccant comprises vinyl groups and / or phenyl groups.

9. The coating composition of claim 8, wherein the desiccant further comprises an alkoxy group, such as a methoxy group, such as wherein the desiccant is vinyltrimethoxysilane or phenyltrimethoxysilane.

10. A coating composition according to any preceding claim, wherein the adhesion promoter is included in a concentration of 0.5 to 8 wt%, such as 1 to 4 wt%, based on the total weight of the coating composition.

11. A coating composition according to any preceding claim, further comprising a tin-based catalyst and / or a titanate-based catalyst, such as an alkoxy titanate, such as tert-n-butyl titanate.

12. The coating composition of claim 11, wherein the tin-based catalyst comprises: (i) an alkyl group, such as a C1 to C6 alkyl group, such as a butyl group; and / or (ii) an acetoxy group, Such as wherein the tin-based catalyst comprises dibutyltin diacetate.

13. A coating composition according to any preceding claim, wherein the thermal insulating agent comprises microspheres, such as hollow microspheres comprising glass, borosilicate, aluminium silicate, ceramic and / or polymeric materials.

14. A coating composition according to any preceding claim, wherein the vehicle comprises an organic solvent, such as: a ketone, such as acetone; an alcohol; an aliphatic hydrocarbon; an aromatic hydrocarbon; an ester; an ether; and / or a halogenated hydrocarbon.

15. A coating composition according to any preceding claim, wherein the coating composition comprises a two-part system, wherein the RTV polymer and / or the adhesion promoter are included in a first part of the two-part system and a catalyst is included in a second part of the two-part system.

16. A coating composition according to any preceding claim, wherein the RTV polymer is dissolved in the carrier, or wherein the RTV polymer is suspended in the carrier.

17. A coating composition according to any preceding claim, wherein the coating composition is substantially free of or completely free of polysiloxane resins other than the RTV polymer, such as substantially free of or completely free of alkoxy functional polysiloxane resins, such as substantially free of or completely free of methoxy functional polysiloxane resins.

18. A coating composition according to any preceding claim, wherein the coating composition, when cured: exhibiting a pull-off bond strength of 50 psi or greater, such as up to 400 psi, after room temperature cure according to ASTM D4541-22; exhibits a pull-off adhesion strength of 50 psi or greater, such as up to 400 psi, after exposure to 260° C. for 100 hours according to ASTM D4541-22; and / or Exhibits a thermal conductivity of 0.12 W / m*K or less when measured at 50° C. according to ASTM 7984-16.

19. A coating composition according to any preceding claim, wherein the coating composition, when applied to a substrate and cured on the substrate, exhibits corrosion protection substantially similar to or greater than the corrosion protection provided by an insulation system having a primer layer, mechanical insulation and a jacket.

20. A substrate at least partially coated with a coating composition according to any preceding claim.

21. A method for coating a substrate, the method comprising applying a coating composition according to any preceding claim to at least a portion of the substrate.

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