Method of applying a sealant composition

Abstract

The invention relates to a process for applying a one-part tin catalyzed room temperature vulcanizable (RTV) silicone composition to a hot porous substrate at a temperature of at least 40°C by first applying an aqueous or solvent borne adhesive composition at a temperature of at least 40°C to the hot porous substrate to create a continuous elastic adhesive film prior to applying the one-part tin catalyzed room temperature vulcanizable (RTV) silicone composition. Also provided is a hot porous substrate coated at a temperature of at least 40°C with a cured layer of a one-part tin catalyzed room temperature vulcanizable (RTV) silicone composition. The porous substrate can for example be a building material such as stone, marble, brick, concrete, cement and other cement-based substrates.

Description

[0001] This invention relates to a method for applying a partially tin-catalyzed room-temperature vulcanizable (RTV) silicone composition to a thermally porous substrate at a temperature of at least 40°C. The method involves first applying an aqueous or solvent-based adhesive composition to the thermally porous substrate at a temperature of at least 40°C to generate a continuous, elastic adhesive film prior to the application of the partially tin-catalyzed RTV silicone composition. A thermally porous substrate is also provided, having been coated with a cured layer of the partially tin-catalyzed RTV silicone composition at a temperature of at least 40°C. This porous substrate can be, for example, a building material such as stone, marble, brick, concrete, cement, and other cementitious substrates.

[0002] Room temperature vulcanizable (RTV) silicone rubber compositions (hereinafter referred to as "RTV compositions") are well known. Typically, such compositions comprise -OH-terminated diorganopolysiloxane polymers or alkoxy-terminated polydiorganosiloxanes, which may have alkylene linkages between the terminal silicon atoms. They are typically condensation-curable and contain one or more suitable crosslinking agents designed to react with -OH and / or alkoxy groups, thereby crosslinking the composition to form, for example, an elastomeric sealant product. These crosslinking agents are typically, but not always, combined with one or more condensation-curing catalysts. Depending on the requirements and where necessary, one or more additional components, such as reinforcing fillers, non-reinforcing fillers, tackifiers, diluents (e.g., plasticizers and / or extenders), stabilizers, chain extenders, biocides, etc., are typically incorporated into these compositions. They can be single-component or multi-component compositions, such as two-component compositions.

[0003] Single-part condensation-curing silicone compositions are used to produce surface- or diffusion-curing silicone elastomers for use as sealants, encapsulants, and / or adhesives. They are typically designed to be as free of water / moisture as possible in the composition, i.e., they are stored in a substantially anhydrous form to prevent premature curing during storage before use. Such single-part condensation-curing silicone compositions are applied to a substrate in the form of a layer typically thinner than 15 mm. If such compositions are applied in the form of a layer thicker than 15 mm, it often results in the material not curing at deeper depths because moisture diffuses very slowly in very deep portions. Surface or diffusion curing (e.g., moisture / condensation) occurs by forming a cured surface layer at the composition / air interface after the sealant / encapsulant has been applied to the substrate surface. After the surface layer is formed, the curing rate depends on the diffusion of moisture from the sealant / encapsulant interface with air to the inside (or core) of the applied silicone composition layer, and the diffusion of condensation reaction byproducts / effluents from the inside (or core) of the material to the outside (or surface), and the rate at which the cured surface layer gradually thickens from the outside / surface to the inside / core over time. The primary (if not the only) source of moisture in these compositions is inorganic filler, such as silica (when present). This filler can be dehydrated before mixing with other components, or water / moisture can be extracted from the mixture during the mixing process to ensure that the resulting sealant composition is substantially anhydrous.

[0004] In contrast, multi-component compositions are designed to cure within the bulk of, for example, a silicone sealant, once the components are mixed together and applied to a substrate surface. They are stored in at least two components, but typically two, before use to prevent premature curing. In these multi-component compositions, one component contains a filler, which typically contains the moisture required to activate condensation curing within the product bulk, and a crosslinking agent and catalyst are in the other component. Multiple (e.g., two-component) condensation curing systems, once mixed together, can achieve overall curing even in portions deeper than 15 mm. In this case, the composition will cure throughout the entire material bulk (after mixing). If a surface layer forms, this only occurs within the first few minutes after application. Shortly thereafter, the product will solidify throughout the entire mass.

[0005] One-part silicone sealant compositions include acetoxy sealants and neutral oxime sealants. Acetoxy sealants are widely used in domestic applications, such as on glass and ceramic substrates. However, they release acetic acid during curing, producing a pungent vinegar odor, and the resulting corrosiveness of the acetic acid hinders their use on many substrates in the construction industry.

[0006] In the 1960s, neutral oxime sealants were developed as a preferred alternative to acetoxy sealants. Oxime sealant compositions rely on silicon-containing crosslinking agents having at least three oxime groups per molecule, typically silanes with three or four oxime groups per molecule. These monomeric oxime sealants are usually cured by condensation using organotin catalysts. Compositions using oxime crosslinking agents produce ketoxime byproducts during curing, most commonly methyl ethyl ketone oxime (MEKO) (an oxime derivative of methyl ethyl ketone).

[0007] HC3CH2C(CH3)=N-OH(MEKO)

[0008] These byproducts are non-corrosive, allowing such sealants to be used, for example, as weather-resistant sealants on building substrates. One reason the construction industry favors oxime sealants is the fact that MEKO has a high boiling point of 153°C and a vapor pressure of 3 mmHg at 20°C (both taken from standard text), making it suitable for use in hot climates without harmful effects on substrate surfaces reaching 40°C or higher during workdays, a situation that often occurs when substrates are exposed to direct sunlight for several hours during the workday. However, despite their non-corrosiveness and other advantages, they are no longer advantageous. This is because MEKO has been identified as a Group 1B carcinogen under the European REACH regulation. This has led the industry to seek alternatives to oxime sealants.

[0009] From a practical standpoint, the construction industry prefers single-component compositions that eliminate the need for pre-application mixing and compositions with excellent processability. One developed alternative is a single-component tin-catalyzed room-temperature vulcanizable (RTV) alkoxy silicone sealant composition. Such sealants release substantially non-corrosive alcohol byproducts during the curing process.

[0010] However, while such compositions meet most of the requirements for replacing oxime sealants, problems have been identified when used in hot countries where ambient temperatures exceed 40°C during the workday. When the substrate surface reaches 40°C or higher, blistering gradually increases within the cured layer of the single-part room temperature vulcanizable (RTV) silicone composition at the sealant / substrate interface as the ambient temperature, particularly the substrate temperature, rises in said hot climates. This can frequently occur when the substrate is exposed to direct sunlight for several hours during the workday.

[0011] When the substrate temperature exceeds 40°C, bubble formation is typically significant in monopartic room temperature vulcanizable (RTV) silicone compositions comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst, leading to surface blistering and poor adhesion. Unbound by existing theory, it is believed that when these monopartic room temperature vulcanizable (RTV) silicone compositions are applied to porous substrates (especially building materials such as stone, marble, brick, concrete, cement, and other typically hydrophilic cementitious substrates) at elevated temperatures (e.g., above 40°C), increasing amounts of moisture / water vapor condense or accumulate at the interface between the monopartic room temperature vulcanizable (RTV) silicone composition and the porous substrate, driven by capillary action and the reactivity of moisture with the composition. This is believed to lead to increasing hydrolysis of alkoxysilyl groups at the interface, and thus accelerated production of alcohols, particularly methanol, at the substrate / composition interface. Typically, the alcohols produced (especially methanol) have low boiling points at atmospheric pressure. Therefore, at elevated temperatures, methanol production accelerates at the interface, gradually exceeding its penetration rate through the bulk composition, resulting in foaming within the cured and eventually cured composition. These bubbles are unacceptable because they increase the volume of the cured product by up to two or three times compared to an equivalent cured product cured at room temperature. Weatherproofing of substrates and other construction processes involving the use of single-component room-temperature vulcanizable (RTV) silicone compositions (such as sealing joints between substrates and / or around windows, window frames and framing, and facades) need to be completed during the workday as required and as needed; waiting for cooler overnight temperatures is not an efficient option. Therefore, this can be a major problem in the construction industry, especially in countries with hot climates.

[0012] Binders or film-forming agents (hereinafter referred to as binders) are film-forming components of coatings such as paints, which are typically mixed with solvents and various additives to produce the desired coating composition. In use, the coating composition is applied to a substrate and allowed to dry or cure, while the solvent evaporates and the binder dries and / or coalesces into a cohesive film coating on the substrate surface.

[0013] This article provides a method for applying a single-part room-temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst to a thermally porous substrate at a temperature of at least 40°C, the method comprising the following steps:

[0014] (i) Applying an aqueous or solvent-based adhesive composition at a temperature of at least 40°C, said aqueous or solvent-based adhesive composition comprising at least 25% by weight of said adhesive, said adhesive being selected from (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinylpyrrolidone, polyvinyl butyral, polyurethane, and silicone resins having the following structure.

[0015] M (a) D (b) T (c) Q (d)

[0016] Where a, b, c, and d are mole fractions, 0 <a<1,b≥0,c≥0,d≥0,c+d> 0 + b + c + d = 1 and a + d ≠ 1; or a mixture of two or more of them;

[0017] Apply to the surface of a thermally porous substrate;

[0018] (ii) Drying and / or curing the aqueous or solvent-based adhesive composition to allow the adhesive to coalesce and form a continuous, elastic adhesive film on the thermally porous substrate, and then...

[0019] (iii) Applying a single-part room temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst to the surface of the continuous elastic adhesive film and allowing it to cure.

[0020] Porous substrates can be, for example, building materials such as stone, marble, brick, concrete, cement, and other cementitious substrates.

[0021] A sealed porous substrate, which is a product of the above method, is also provided.

[0022] This article also provides a thermally porous substrate coated with a curing layer of a single-component room temperature vulcanizable (RTV) silicone composition at a temperature of at least 40°C, said curing layer being obtained or obtainable through the following steps:

[0023] (i) at a temperature of at least 40°C

[0024] A water-based or solvent-based adhesive composition comprising at least 25% by weight of the adhesive, wherein the adhesive is selected from (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinylpyrrolidone, polyvinyl butyral, polyurethane, and silicone resins having the following structures.

[0025] M (a) D (b) T (c) Q(d)

[0026] Where a, b, c, and d are mole fractions, 0 <a<1,b≥0,c≥0,d≥

[0027] 0, c+d>0, a+b+c+d=1 and a+d≠1, or a mixture of two or more of them;

[0028] Apply to the surface of a thermally porous substrate;

[0029] (ii) Drying and / or curing the aqueous or solvent-based adhesive composition to allow the adhesive to coalesce and form a continuous, elastic adhesive film on the thermally porous substrate, and then...

[0030] (iii) Applying a single-part room temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst to the surface of the continuous elastic adhesive film and allowing it to cure.

[0031] This article also provides

[0032] A water-based or solvent-based adhesive composition comprising at least 25% by weight of the adhesive, wherein the adhesive is selected from (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinylpyrrolidone, polyvinyl butyral, polyurethane, and silicone resins having the following structures.

[0033] M (a) D (b) T (c) Q (d)

[0034] Where a, b, c, and d are mole fractions, 0 <a<1,b≥0,c≥0,d≥0,c+d> 0, a+b+c+d=1 and a+d≠1, or a mixture of two or more of them;

[0035] Use in a method for applying a single-part room-temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst to a thermally porous substrate at a temperature of at least 40°C, the method comprising the steps of:

[0036] An aqueous or solvent-based adhesive composition containing at least 25% by weight of the adhesive is applied to the surface of a thermally porous substrate at a temperature of at least 40°C.

[0037] The aqueous or solvent-based adhesive composition containing at least 25% by weight of the adhesive is dried and / or cured, enabling the adhesive to coalesce and form a continuous, elastic adhesive film on the thermally porous substrate; then...

[0038] A single-part room temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst is applied to the surface of the continuous elastic adhesive film and cured thereon.

[0039] A method is also provided for filling a space between a first substrate and a second substrate to create a seal therebetween, wherein at least one of the first substrate and the second substrate is a thermally porous substrate at a temperature of at least 40°C, the seal having a cured layer of a single-part room-temperature vulcanizable (RTV) silicone composition, the method comprising:

[0040] (i) at a temperature of at least 40°C

[0041] A water-based or solvent-based adhesive composition comprising at least 25% by weight of the adhesive, wherein the adhesive is selected from (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinylpyrrolidone, polyvinyl butyral, polyurethane, and silicone resins having the following structures.

[0042] M (a) D (b) T (c) Q (d)

[0043] Where a, b, c, and d are mole fractions, 0 <a<1,b≥0,c≥0,d≥

[0044] 0, c+d>0, a+b+c+d=1 and a+d≠1, or a mixture of two or more of them;

[0045] At least partially applied to the surface of the thermally porous substrate;

[0046] (ii) Drying and / or curing the aqueous or solvent-based adhesive composition to enable the adhesive to coalesce and form a continuous, elastic adhesive film at least on the thermally porous substrate; then

[0047] (iii) Applying a single-part room temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst to the surface of the continuous elastic adhesive film and allowing it to cure.

[0048] The concept of “include” as used in this article is used in its broadest sense to mean and encompass the concepts of “including” and “consisting of”.

[0049] For the purposes of this application, "substituted" means that one or more hydrogen atoms in a hydrocarbon group are replaced by another substituent. Examples of such substituents include, but are not limited to, halogen atoms such as chlorine, fluorine, bromine, and iodine; groups containing halogen atoms such as chloromethyl, perfluorobutyl, trifluoroethyl, and nonafluorohexyl; oxygen atoms; groups containing oxygen atoms such as (meth)acrylic acid and carboxyl groups; nitrogen atoms; groups containing nitrogen atoms such as amino, amide, and cyano functional groups; sulfur atoms; and groups containing sulfur atoms such as mercapto groups.

[0050] A single-component room-temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst meets most of the requirements as an alternative to neutral oxime sealants. However, this foaming effect at high temperatures is an inherent problem with alkoxy-cured sealants when applied directly to the surface of a thermally porous substrate, which is not encountered in the case of oxime sealants because MEKO has the aforementioned high boiling point of 153°C and a vapor pressure of 3 mmHg at 20°C (both from standard text), which is different from the alcohol byproducts generated during the curing process of a single-component room-temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst.

[0051] The method described herein includes contacting an aqueous or solvent-based adhesive composition with a hot surface of a porous substrate at a temperature of at least 40°C, then drying and / or curing the aqueous or solvent-based adhesive composition on the substrate surface to form a continuous elastic adhesive film, then applying a single-part room temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst onto the continuous elastic adhesive film on the substrate, and then exposing the combination of the substrate and the sealant composition to atmospheric moisture to obtain a silicone sealant bonded to a hot porous substrate, etc.

[0052] This method produces a cured product of a single-component room temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst bonded to a thermally porous substrate at a temperature of at least 40°C. When directly applied to the surface of the thermally porous substrate, this cured product contains a reduced number of bubbles compared to an equivalent cured product. In addition to the reduced number of bubbles, the diameter of the formed bubbles is also smaller. Therefore, we surprisingly found that providing a continuous, elastic adhesive film on the thermally porous substrate before applying the single-component room temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst effectively prevents capillary action in the substrate and thus prevents the formation of alcohols at the substrate / single-component room temperature vulcanizable (RTV) silicone composition interface.

[0053] Importantly, the resulting continuous elastic adhesive film produced when the aqueous or solvent-based adhesive composition is applied to the substrate at a temperature of at least 40°C is continuous and elastic, i.e., not easily broken. The film thickness is, or preferably, a minimum of 30 μm. This can be determined, for example, in a laboratory setting, by checking the substrate thickness before applying the aqueous or solvent-based adhesive composition, and then subsequently checking the thickness of the substrate with the applied continuous elastic coating and identifying any differences. Typically, the thickness of the continuous elastic adhesive film is in the range of 30 μm to 300 μm, alternatively in the range of 50 μm to 200 μm.

[0054] This enables the resulting continuous elastic adhesive film to physically separate the single-component room temperature vulcanizable (RTV) silicone composition from the thermal porous substrate during the curing process at a temperature of at least 40°C on the substrate.

[0055] The aqueous or solvent-based adhesive composition contains at least 25% by weight of a suitable adhesive. The adhesive may be any suitable adhesive selected from the following: (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinylpyrrolidone, polyvinyl butyral, polyurethane, and silicone resins having the following structures:

[0056] M (a) D (b) T (c) Q (d)

[0057] When a, b, c, and d are mole fractions, 0 can be used. <a<1,b≥0,c≥0,d≥0,c+d> 0, a+b+c+d=1 and a+d≠1.

[0058] For example, for example, for (meth)acrylic resins, the binder used can have any suitable weight-average molecular weight, such as in the range of 10,000 g / mol to 5,000,000 g / mol, for example 20,000 g / mol to 1,000,000 g / mol, alternatively 30,000 g / mol to 750,000 g / mol, alternatively 50,000 g / mol to 750,000 g / mol, alternatively 75,000 g / mol to 750,000 g / mol. As used herein, unless otherwise stated, the phrase "molecular weight" refers to the weight-average molecular weight measured by gel permeation chromatography (GPC) relative to a polystyrene (PS) standard.

[0059] Resins based on (meth)acrylic acid are formed by the polymerization of esters of acrylic acid or methacrylic acid with various specific (meth)acrylic acid ester monomers. The term (meth)acrylic acid ester as used herein is intended to refer to both acrylates and methacrylates.

[0060] When the binder in an aqueous or solvent-based binder composition comprising at least 25% by weight of the binder is a (meth)acrylic resin, the (meth)acrylic resin may comprise or consist of particles and / or microparticles of a (meth)acrylic polymer resin. Such (meth)acrylic resin particles will have a particle diameter in the range of 75 nm to 450 nm, alternatively 100 nm to 375 nm, alternatively 115 nm to 375 nm, or alternatively 150 nm to 300 nm. As used herein, unless otherwise stated, the term “average particle size” with respect to (meth)acrylic resins refers to the particle size determined by light scattering (LS) using a BI-90 particle size analyzer from Brookhaven Instruments Corp. (Holtsville, NY).

[0061] (Meth)acrylic resins can have any suitable weight-average molecular weight, for example, from 30,000 g / mol to 1,000,000 g / mol, for example, from 50,000 g / mol to 750,000 g / mol, and alternatively from 100,000 g / mol to 750,000 g / mol. As used herein, unless otherwise stated, the phrase "molecular weight" (for (meth)acrylic resins) refers to the weight-average molecular weight measured relative to polystyrene (PS) standards by gel permeation chromatography (GPC).

[0062] (Meth)acrylic resins can have any suitable glass transition temperature (Tg), for example, they can have a Tg in the range of -50°C to 100°C. (Meth)acrylic resins can have a pH in the range of 7 to 10. As used herein, unless otherwise stated, the term "Tg" or "glass transition temperature" for polymers relating to (meth)acrylic emulsions and their components refers to the Tg of the polymer calculated using the Fox equation (TGFox, Bulletin of the American Physical Society, Vol. 1, No. 3, p. 123 (1956)).

[0063] Representative, non-limiting examples of aqueous dispersions of (meth)acrylic acid polymers that can be used in the commercial production of adhesives disclosed herein include those sold under the trade name PRIMAL. TM SS-640, PRIMAL TM AC-339, PRIMAL TM E-822K, UCAR TM Latex DL 420G, PRIMAL TM AC-337ER, PRIMAL TM CM-330, PRIMAL TM AC-285 and PRIMAL TM CM-160, RHOPLEX TM SG-10, RHOPLEX TM EI-2000, RHOPLEX TM 78C and RHOPLEX TM EC-1741 (both purchased from Dow, Inc.) and from ROHM in Darmstadt, Germany. PLEXIGLAS GmbHof Darmstadt Germany) TM 6N, PLEXIGLAS TM 7N and PLEXIGLAS TM 8N.

[0064] To avoid ambiguity, the silicone resins according to this disclosure can be described using the following general formula with shorthand (abbreviated) nomenclature:

[0065] M (a) D (b) T (c) Q (d)

[0066] Where a, b, c, and d are mole fractions, 0 <a<1,b≥0,c≥0,d≥0,c+d> 0, a+b+c+d=1 and a+d≠1 (i.e., a+d cannot be 1), and M=(R 1 R 2 R 3 SiO 1 / 2 D = (R) 4 R 5 'SiO 2 / 2 ), T=(R 6 'SiO 3 / 2 And Q = (SiO) 4 / 2 The resin, based on standard polystyrene, was obtained by gel permeation chromatography and has a weight-average molecular weight of about 1,000 to about 100,000.

[0067] Each R 1 -R 4 R 5 'and R 6 The group is independently selected from monovalent hydrocarbon groups, methanol groups, alkoxy groups (preferably methoxy or ethoxy) or amino groups. Suitable exemplary monovalent hydrocarbon groups include, but are not limited to, alkyl groups such as methyl, ethyl, propyl, pentyl, octyl, undecyl, and octadecyl; alkenyl groups, cycloalkyl groups such as cyclopentyl and cyclohexyl; and aryl groups such as phenyl, tolyl, xylyl, benzyl, and 2-phenylethyl, and any combination thereof.

[0068] Suitable alkenyl groups contain 2 to about 6 carbon atoms, and may be, for example but not limited to, vinyl, allyl, and hexenyl. Organosilicon resins can be DT resins, MT resins, MDT resins, DTQ resins, MTQ resins, MDTQ resins, DQ resins, DTQ resins, MTQ resins, or MDQ resins, wherein the resin primarily contains D units (R... 4 R 5 SiO 2 / 2 ) and T unit (R 6 SiO 3 / 2 DT resins are particularly preferred. MQ resins (where a+d=1) are not used because they are too powdery and cannot provide a continuous elastic film.

[0069] A solution of an aqueous or solvent-based adhesive composition may consist of only an adhesive and a solvent, provided that the adhesive / solvent combination is viscous enough to be applied and cured / dried in a sufficiently thick layer.

[0070] When the water-based or solvent-based adhesive composition is water-based, the solvent used is water or substantially, at least 95%, water and, for example, a small amount of alcohol.

[0071] When the aqueous or solvent-based adhesive composition is a solvent-based adhesive composition, the adhesive used is dissolved in an organic solvent suitable for that particular adhesive.

[0072] Depending on the adhesive used, the organic solvent may be selected from one or more of the following:

[0073] Straight-chain or branched alkanes having 6 to 16 carbons, such as hexane, heptane, and octane; isoalkanes having 6 to 16 carbons, such as isodecane, isodecane, and isohexadecane; aromatics, such as naphtha, benzene, toluene, and xylene; alcohols, such as methanol, ethanol, isopropanol, butanol, and n-propanol; aldehydes; ketones, such as methyl isobutyl ketone, acetone, and methyl ethyl ketone; amines; esters, such as tert-butyl acetate, methyl acetate, ethyl acetate, n-butyl acetate, methyl formate, isodecane neopentanoate, isohexyl neopentanoate, ethyl 3-ethoxypropionate, tridecyl neopentanoate, octyl dodecyl neopentanoate, diisobutyl adipate, diisopropyl adipate, and octyl palmitate; ethers, such as octyl ether; diols, such as propanediol. Alcohols; glycol ethers, such as glycol n-butyl ether, propylene glycol n-butyl ether, propylene glycol dioctyl ester / didecanoate, propylene glycol methyl ether, dipropylene glycol methyl ether, propylene glycol n-butyl ether, propylene glycol n-propyl ether, ethylene glycol n-butyl ether, and propylene glycol methyl ether (PGME); glycol esters, such as neopentyl glycol heptanoate, ethylene glycol distearate, propylene glycol methyl ether acetate, and propylene glycol methyl ether acetate (PGMEA); halogenated hydrocarbons, such as dichloromethane, 1,1,1-trichloroethane, and dichloromethane; chloroform; aromatic halides and other solvents, such as dimethyl sulfoxide; dimethylformamide, acetonitrile; tetrahydrofuran; petroleum solvents; solvent oils; N-methylpyrrolidone; etc., and their derivatives, modifications, and combinations thereof.

[0074] The adhesive can be applied to the surface of a thermal substrate as an aqueous composition comprising water and at least 25% by weight of the adhesive, alternatively 25% to 75% by weight of the adhesive, or alternatively 27.5% to 75% by weight of the adhesive.

[0075] Alternatively, the binder can be applied to a solvent-based composition comprising a non-aqueous solvent and at least 25% by weight of the binder in the composition, or alternatively, 25% to 75% by weight of the binder in the composition, or alternatively, 27.5% to 75% by weight of the binder in the composition.

[0076] Optionally, one or more additives may be present in the aqueous or solvent-based adhesive composition. These may include, for example, one or more silanes having at least two hydrolyzable groups per molecule, alternatively silane coupling agents (such as aminosilanes, epoxysilanes, thiosilanes, etc.) and catalysts, such as titanates, zirconates and / or organometallic aluminum compounds, and any combination thereof.

[0077] In the case of silanes, one or more silanes may be provided having at least two or three hydrolyzable groups per molecule. Any suitable hydrolyzable group may be used, such as alkoxy, acetoxy, and oxime groups, but alkoxy groups are preferred. Alkoxy groups may be the same or different and typically have 1 to 10 carbons, alternatively 1 to 6 carbons, and alternatively methoxy or ethoxy groups. When a silane has two or three hydrolyzable groups, such as two or three alkoxy groups, each other group is suitably a non-hydrolyzable organic group bonded to silicon, typically a hydrocarbon group that can be substituted with halogens such as fluorine and chlorine. Examples of such other groups include alkyl groups (e.g., methyl, ethyl, propyl, and butyl); cycloalkyl groups (e.g., cyclopentyl and cyclohexyl); alkenyl groups (e.g., vinyl and allyl); aryl groups (e.g., phenyl and tolyl); aralkyl groups (e.g., 2-phenylethyl); and groups obtained by substituting all or part of the hydrogens in the aforementioned organic groups with halogens. However, preferably, each other organic group bonded to silicon is an alkyl group (such as a methyl or ethyl group) having 1 to 6 carbons or an alkenyl group (such as a vinyl group) having 2 to 6 carbons.

[0078] Specific examples of silanes that can be incorporated as additives into the aqueous or solvent-based binder compositions include, but are not limited to, alkyltrialkoxysilanes such as methyltrimethoxysilane (MTM), ethyltrimethoxysilane, and methyltriethoxysilane; alkenyltrialkoxysilanes such as vinyltrimethoxysilane and vinyltriethoxysilane; and isobutyltrimethoxysilane (iBTM). Other suitable silanes include phenyltrimethoxysilane, alkoxytrioxime silane, alkenyltrioxime silane, 3,3,3-trifluoropropyltrimethoxysilane, methyltris(methylethyl ketone oxime)silane, vinyltris(methylethyl ketone oxime)silane, methyltris(isopropenoxy)silane, vinyltris(isopropenoxy)silane, (ethylenediaminepropyl)trimethoxysilane, vinyltrimethoxysilane, tetraalkyl orthosilicate having the general formula SiOR4, tetraethoxysilane, mercaptofunctionalized silane, glycidoxypropyltrimethoxysilane, and any combination thereof.

[0079] In the case of titanates, zirconates and / or organometallic aluminum compounds or any combination thereof, titanates may include, but are not limited to, tetrabutyl titanate, tetrapropoxy titanate, tetraethoxy titanate, tetrapentyl titanate, titanium diisopropoxydiethylacetoacetate, titanium diisopropoxydiacetylacetonate and any combination thereof; zirconates may include, but are not limited to, zirconium acetylacetonate; and organometallic aluminum compounds may be, but are not limited to, aluminum acetylacetonate.

[0080] In one embodiment, the aqueous or solvent-based adhesive composition may be a primer composition, provided that the adhesive used is present in an amount of at least 25% by weight of the primer composition, or alternatively in an amount of 25% to 75% by weight of the primer composition, or alternatively in an amount of 27.5% to 75% by weight of the primer composition.

[0081] A primer is a pre-coating applied to a substrate and allowed to dry and / or cure to provide improved adhesion between the substrate and any subsequent coating applied thereon. Primers are designed to provide enhanced adhesion between the substrate and the coating. However, the use of primers is generally not preferred because they can be unreliable, may have quality control and reliability issues, and traditionally contain a high proportion of organic solvents that evaporate during the drying / curing process, often leading to undesirable volatile organic compound (VOC) environmental problems.

[0082] Small quantities of commercial primers contain at least 25% by weight of binder in the primer composition. Such primers are designed to promote film formation and adhesion of room temperature vulcanizable (RTV) silicone compositions when applied to a substrate at room temperature (i.e., 20°C to 25°C for ceramics). However, these are generally unnecessary for adhering room temperature cured silicone materials to porous substrates such as stone, marble, brick, concrete, cement, and other cementitious substrates. Furthermore, there is no teaching that primers need to be applied to porous substrates such as stone, marble, brick, concrete, cement, and other cementitious substrates at a temperature of at least 40°C, and it is believed that no prior art demonstrates that applying such primer compositions to substrates at a temperature of at least 40°C will prevent or substantially prevent foaming problems occurring at those temperatures in single-component room temperature vulcanizable (RTV) silicone compositions comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst. Therefore, the method described herein is a surprising development that appears to solve a major problem in hot climates. Unbound by existing theories, it is believed that when a single-part room-temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst is later applied on top of an elastic adhesive film, the application of an aqueous or solvent-based adhesive composition results in the formation of an elastic adhesive film that blocks pores on the substrate surface and thus prevents bubbling.

[0083] In another embodiment, it is determined that, if necessary, a predetermined amount of binder may be introduced into the primer composition to form an aqueous or solvent-based binder composition comprising at least 25% by weight of binder in the primer composition, the binder being selected from (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinylpyrrolidone, polyvinyl butyral, polyurethane, or silicone resins having the following structure:

[0084] M (a) D (b) T (c) Q (d)

[0085] Where a, b, c, and d are mole fractions, 0 <a<1,b≥0,c≥0,d≥0,c+d> 0, a+b+c+d=1 and a+d≠1, or a mixture thereof. The adhesion properties of water-based or solvent-based adhesive compositions in primers containing a base coat or modified primers containing additional binders are considered redundant for this application, provided that the modified primer composition can form a suitable continuous elastic adhesive film when applied to a thermally porous substrate at 40°C.

[0086] Any suitable primer may be used for this application, provided that it contains the required amount of binder (at least 25% by weight) in its composition, or that it may be modified to contain such binder. Such primers may be water-based or solvent-based. In the case of solvent-based primers, the solvent may be any of those listed above for binder compositions. They may contain a variety of other components, such as one or more silanes having at least three hydrolyzable groups per molecule, and catalysts, such as titanates, zircons, and / or organometallic aluminum compounds as described above. They may additionally include one or more organotin compounds, such as, but not limited to, alkyltin esters, such as dibutyltin dioctanoate, dibutyltin dimaleate, butyltin 2-ethylhexanoate, dimethyltin dineodecyl ester, or dibutyltin dilaurate, dibutyltin acetate, and dibutyltin 2-ethylhexanoate, and any combination thereof.

[0087] Any suitable silicone sealant primer suitable for priming porous substrates described herein (i.e., building and / or construction materials used to form the exterior of buildings, such as concrete, marble, brick, and stone) can be used as the water-based or solvent-based adhesive compositions described herein. For example, commercially available primers include DOWSIL. TM Architectural Primer B and DOWSIL TM Architectural primer P, and commercial primers that can be used as water-based or solvent-based binder compositions when modified with the addition of binders, may include DOWSIL. TM 1200OS primer and DOWSIL TM Primer-C, all of which are commercially available from Dow Silicones Corporation of Midland, Michigan, USA. Preferably, when the commercial primer is modified, the binder added to the primer and the primer itself are miscible in the combination used.

[0088] In step (i) of the above method, an aqueous or solvent-based adhesive composition containing at least 25% by weight of the adhesive is applied to the surface of a thermally porous substrate at a temperature of at least 40°C. The adhesive is selected from (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinylpyrrolidone, polyvinyl butyral, polyurethane, or silicone resins, or mixtures of two or more of these, as described above. The thermally porous substrate is a building and / or construction material used to form the exterior of a building, such as stone, marble, brick, concrete, cement, and other cementitious substrates. For example, in the case of stone, the substrate can be a stone facade that can be heated to temperatures well above 40°C under direct sunlight.

[0089] Any suitable silicone sealant primer suitable for priming porous substrates (i.e., building and / or construction materials used to form the exterior of buildings, such as concrete, marble, brick, and stone) described herein may be used in this disclosure. The aqueous or solvent-based adhesive composition is brought into contact with the thermally porous surface by conventional means such as extrusion, coating, injection, scraping, wiping, and rolling. The surface of the porous substrate is at a temperature of at least 40°C.

[0090] The binder composition can be prepared by mixing the binder and a selected solvent together and introducing any other components simultaneously or subsequently. Alternatively, if the aqueous or solvent-based binder composition used is a modified primer composition, a predetermined amount of binder can be mixed into the primer composition to ensure that the binder composition applied to a hot porous substrate surface at a temperature of at least 40°C contains at least 25% by weight of binder in the modified primer composition. The resulting binder composition can be in the form of a solution, emulsion, or dispersion, depending on the solubility of the other components in the solvent.

[0091] In step (ii) of this method, the aqueous or solvent-based adhesive composition is dried and / or cured to allow the adhesive to coalesce and form a continuous, elastic adhesive film on the thermally porous substrate. The resulting continuous, elastic adhesive film contains all the non-volatile components of the aqueous or solvent-based adhesive composition, and therefore, if a modified primer is used, all the non-volatile components of a modified silicone sealant primer. In practice, it is possible that one or more of the components of the aqueous or solvent-based adhesive composition applied herein may react with the adhesive during the formation of the continuous, elastic adhesive film. Given the temperature of the thermally porous substrate and caused by sunlight / air near the substrate, drying / curing the aqueous or solvent-based adhesive composition does not require methods such as heating. Increased climatic temperatures will actually accelerate the drying / curing period compared to drying / curing at temperatures such as 20°C to 25°C.

[0092] In step (iii), a single-part room-temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst is applied to the surface of the continuous elastic adhesive film obtained in step (ii) and cured thereon. It is applied on top of the continuous elastic adhesive film and then cured at the ambient temperature at the time of application. When a single-component room temperature vulcanizable (RTV, i.e., typically 20°C to 25°C) silicone composition is applied to a thermally porous substrate at temperatures above 40°C, the method described herein prevents or minimizes undesirable blistering problems because the continuous, elastic adhesive film created by applying an aqueous or solvent-based adhesive composition to the surface of the thermally porous substrate effectively isolates the single-component room temperature vulcanizable (RTV) silicone composition, comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst, from the surface of the substrate, and prevents direct contact between the substrate surface and the single-component room temperature vulcanizable (RTV) silicone composition during the curing process if blistering occurs.

[0093] Most monomeric room-temperature vulcanizable (RTV) silicone compositions, which have at least two alkoxy groups per molecule and contain a tin (IV)-based catalyst, typically contain at least four components.

[0094] 1. An organopolysiloxane polymer having at least two alkoxy groups per molecule, typically having at least two trialkoxy-silyl terminal groups per molecule;

[0095] 2. One or more suitable crosslinking agents;

[0096] 3. Packing materials; and

[0097] 4. Tin (IV) based catalysts.

[0098] Monomeric room-temperature vulcanizable (RTV) silicone compositions having at least two alkoxy groups per molecule and containing a tin (IV)-based catalyst typically also include a variety of additives incorporated into the composition to meet the necessary performance requirements of the applicant / construction industry using them. Such additives typically include one or more of tackifiers, diluents (e.g., plasticizers and / or extenders), chain extenders, flame retardants, solvent-resistant additives, biocides, etc., and are usually incorporated into these compositions as needed and where required.

[0099] One advantage of this method is that any suitable single-part room temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and containing a tin (IV)-based catalyst can be applied to a thermally porous substrate at a temperature of at least 40°C by preparing a continuous elastic adhesive film on the thermally porous substrate prior to applying a single-part room temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst. An example of a typical single-part room temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst is provided below; however, it should be understood that such a composition is provided only as an example of the types of compositions that can be used and is by no means intended to limit the range of single-part room temperature vulcanizable (RTV) silicone compositions comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst that can now be applied to thermally porous substrates by this new method. A monomeric room-temperature vulcanizable (RTV) organosilicon composition having at least two alkoxy groups per molecule and containing a tin (IV)-based catalyst can be as follows:

[0100] (I) Organopolysiloxane polymers having at least two alkoxy groups per molecule, typically at least two trialkoxy-silyl terminal groups per molecule; for example

[0101] Organopolysiloxane polymers having at least two hydroxyl groups or hydrolyzable groups per molecule as follows:

[0102] X 3-n R n Si-Z-(R 1 y SiO (4-y) / 2 ) z –SiR 1 2-Z-Si-R n X 3-n (1)

[0103] Each X is independently a hydroxyl group or an alkoxy group, and each R is an alkyl, alkenyl, or aryl group. 1 X is an X group, alkyl group, alkenyl group or aryl group and Z is a divalent organic group;

[0104] n is 0 or 1, y is 0, 1 or 2, and preferably 2, and z is an integer, such that the organopolysiloxane polymer has a viscosity of 30,000 mPa·s to 150,000 mPa·s at 25°C, in an amount of 30% to 90% by weight of the composition.

[0105] (II) A suitable crosslinking agent having three or more hydrolyzable groups per molecule;

[0106] (III) Fillers selected from precipitated silica, pyrolytic silica, or precipitated calcium carbonate, or mixtures of two or more thereof;

[0107] (IV) Tin-based (IV) catalysts.

[0108] Organopolysiloxane polymers (I) with at least two alkoxy groups per molecule

[0109] Organopolysiloxane polymers (I) having at least two alkoxy groups per molecule have the following formula:

[0110] X 3-n R n Si-Z-(R 1 y SiO (4-y) / 2 ) z -SiR 1 2-Z-Si-R n X 3-n (1)

[0111] In the above formula, each X is independently a hydroxyl group or an alkoxy group, provided that each polymer contains at least two alkoxy groups. In one embodiment, all X groups may be the same or different alkoxy groups. Preferably, the alkoxy group has between 1 and 10 carbons, and exemplary alkoxy groups are methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, tert-butoxy, isobutoxy, pentoxy, hexoxy, and 2-ethylhexoxy; dialkoxy groups, such as methoxymethoxy or ethoxymethoxy; and alkoxyaryloxy groups, such as ethoxyphenoxy; alternatively, each X is an alkoxy group having one to six carbons, alternatively having one to four carbons, or alternatively a methoxy or ethoxy group.

[0112] Each R group is an alkyl, alkenyl, or aryl group, alternatively each R is an alkyl group having 1 to 6 carbons, an alkenyl group having 2 to 6 carbons (such as vinyl, allyl, and hexenyl groups), or an aryl group having 6 to 12 carbons; alternatively each R is an alkyl group having 1 to 6 carbons, or an aryl group having 6 to 12 carbons; alternatively each R is an alkyl group having 1 to 6 carbons; alternatively each R is an ethyl or methyl group. In one embodiment, R may comprise a substituted aliphatic organic group, such as a 3,3,3-trifluoropropyl group, an aminoalkyl group, a polyaminoalkyl group, and / or an epoxyalkyl group.

[0113] Each R 1It is an X group, or an R group, provided that there are at least two X groups cumulatively and / or R groups per molecule. 1 The group is an alkoxy group, and optionally each R 1 It is an R group. It is possible that some R groups... 1 The groups can be siloxane branches derived from the polymer backbone, and these branches can have terminal groups as described above.

[0114] Each Z is a divalent organic group, typically an alkylene group having 2 to 10 carbons, such as, for example, ethylene, propylene, butylene, pentylene, and / or hexylene groups; alternatively, an alkylene group having 2 to 6 carbons, and alternatively, an alkylene group having 2 to 5 carbons. The subscript n is zero or 1, alternatively zero; each subscript y is 0, 1, or 2, and preferably 2. Although y is 0, 1, or 2, it is essentially y = 2, for example, at least 90%, alternatively 95%, of R. 1 y SiO (4-y) / 2 The group is characterized by y = 2. The subscript z is an integer such that the organopolysiloxane polymer has a viscosity of 30,000 mPa·s to 150,000 mPa·s, or alternatively 40,000 mPa·s to 140,000 mPa·s at 25°C, and therefore z is an integer from 300 to 2000.

[0115] The viscosity of component (I) can be measured by any suitable method, such as according to corporate test method CTM 0050, which is publicly available and based on ASTM D1084-16 Method B, using a Brookfield DV-III Ultra rheometer equipped with a conical plate geometry, at 5 rpm for 2 min using a mandrel 52.

[0116] Component (I) is present in the single-part room temperature vulcanizable (RTV) silicone composition in an amount of 30% to 90% by weight of the composition, alternatively 35% to 75% by weight of the composition, and alternatively 35% to 60% by weight of the composition.

[0117] The organopolysiloxane polymer (I) may be a single siloxane represented by formula (1), or it may be a mixture of organopolysiloxane polymers represented by the above formula. Therefore, it may be a "siloxane polymer mixture", so organopolysiloxane polymer (I) means including any single organopolysiloxane polymer (I) or a mixture of organopolysiloxane polymers (I).

[0118] The degree of polymerization (DP) (i.e., essentially z in the above formula) is generally defined as the number of monomer units in a macromolecule or polymer or oligomer molecule of organosilicon. Synthetic polymers always consist of a mixture of macromolecules with different degrees of polymerization and therefore different molecular weights. Different types of average polymer molecular weights exist, which can be measured in various experiments. The two most important average polymer molecular weights are number-average molecular weight (Mn) and weight-average molecular weight (Mw). The Mn and Mw of organosilicon polymers can be determined by gel permeation chromatography (GPC) using polystyrene standards, with an accuracy of approximately 10% to 15%.

[0119] This technique is standard and produces Mw, Mn, and polydispersity index (PI). Degree of polymerization (DP) = Mn / Mu, where Mn is the number-average molecular weight from GPC measurements, and Mu is the molecular weight of the monomer unit. PI = Mw / Mn. DP is correlated with the viscosity of the polymer via Mw; the higher the DP, the higher the viscosity. In this disclosure, the number-average and weight-average molecular weight values ​​of component (I) can be determined, for example, using a Waters 2695 separation module (Waters Corporation of MA, USA) equipped with a vacuum degasser and a Waters 2414 refractive index detector. Analysis can then be performed using certified-grade toluene flowing at 1.0 mL / min as the eluent. Data collection and analysis can be performed using Waters Empower GPC software.

[0120] Polymer (I) can be prepared by any suitable route, for example, by preparing alkoxy-terminated polydiorganosiloxanes from silanol-terminated polydiorganosiloxane starting materials, wherein the silanol-terminated polydiorganosiloxane starting materials comprise: -

[0121] Step (i) involves reacting the silanol-terminated polydiorganosiloxane starting material with one or more polyalkoxysilane starting materials in the presence of an alkaline-terminated catalyst starting material; and after step (i), step (ii) involves adding an acidic stabilizer / neutralizer selected from the following:

[0122] One or more fatty acids having 8 to 26 carbons;

[0123] Alkyl sulfonic acids having 1 to 10 carbon atoms;

[0124] Acidic pyrolysis of silicon dioxide and / or

[0125] One or more acidic liquid polybutadienes or mixtures thereof.

[0126] Suitable crosslinking agents (II) with three or more alkoxy groups per molecule.

[0127] Component (II) is one or more crosslinking agents comprising a silicon-containing compound having at least three alkoxy groups per molecule that react with the alkoxy and optional hydroxyl groups in component (I).

[0128] Component (II) can be a silicon-containing compound having at least three alkoxy groups per molecule, for example:

[0129] One or more silanes having at least three hydrolyzable groups per molecule;

[0130] One or more dipodal silanes having at least two silyl groups, each silyl group containing at least one hydrolyzable group or

[0131] Other suitable silicon-containing compounds having at least three hydroxyl groups and / or hydrolyzable groups per molecule.

[0132] For the purposes of this disclosure, a bipodial silane comprises two silicon atoms, each silicon atom having at least one hydrolyzable group, wherein the silicon atoms are separated by an organic polymer chain, a siloxane polymer chain, or a copolymer chain. Typically, each silyl group on the bipodial silane may be a terminal group.

[0133] The hydrolyzable group of component (II) may be selected from acyloxy groups (e.g., acetoxy, octyloxy, and benzoyloxy groups); ketoxime groups (e.g., dimethyl ketoxime and isobutyl ketoxime); alkoxy groups (e.g., methoxy, ethoxy, and propoxy); and alkenoxy groups (e.g., isopropenoxy and 1-ethyl-2-methylethoxy). In some cases, the hydrolyzable group may include a hydroxyl group. Alternatively, the hydrolyzable group may be selected from acyloxy groups; alkoxy groups and / or alkenoxy groups. In a preferred embodiment, the hydrolyzable group is an alkoxy group having 1 to 10 carbons.

[0134] Therefore, when component (II) is a silane, the silane can have the following structure:

[0135] R 8 j Si(OR 9 ) 4-j

[0136] Each R 9 They may be the same or different and are hydrogen or contain at least one carbon, alternatively 1 to 20 carbons, alternatively 1 to 10 carbons, alternatively 1 to 6 carbons of alkyl groups. The value of j is 0 or 1. Although each R 9 The groups can be the same or different, but preferably at least two R groups. 9 The groups are the same, and alternatively, at least three R groups are required. 9The groups are the same, and alternatively, when j is 0, all R 9 The functional groups are the same.

[0137] Therefore, specific examples of reactive silanes (II) when j is zero include tetraethyl orthosilicate, tetrapropyl orthosilicate, tetra-n-butyl orthosilicate, and tetra-tert-butyl orthosilicate.

[0138] When j is 1, group R 8 It exists. R 8 It is a silicon-bonded organic group selected from substituted or unsubstituted straight-chain or branched monovalent hydrocarbon groups, cycloalkyl groups, aryl groups, aralkyl groups, or any of the aforementioned groups, having at least one carbon atom, wherein at least one hydrogen atom bonded to the carbon is replaced by a halogen atom, or an organic group having an epoxy group, glycidyl group, acyl group, carboxyl group, ester group, amino group, amide group, (meth)acryloyl group, mercapto group, isocyanurate group, or isocyanate group.

[0139] Suitable as R 8 The unsubstituted monovalent hydrocarbon group may include alkyl groups (e.g., methyl, ethyl, propyl, and other alkyl groups), alkenyl groups (such as vinyl groups), and cycloalkyl groups may include cyclopentyl and cyclohexyl groups. For illustrative purposes, suitable or appropriate as R 8 The substituted groups may include 3-hydroxypropyl groups, 3-(2-hydroxyethoxy)alkyl groups, halopropyl groups, 3-mercaptopropyl groups, trifluoroalkyl groups such as 3,3,3-trifluoropropyl, 2,3-epoxypropyl, 3,4-epoxybutyl, 4,5-epoxypentyl, 2-glycidoxyethyl, 3-glycidoxypropyl, 4-glycidoxybutyl, 2-(3,4-epoxycyclohexyl)ethyl, 3-(3,4-epoxycyclohexyl)alkyl, aminopropyl, N-methylaminopropyl, N-butylaminopropyl, N,N-dibutylaminopropyl, 3-(2-aminoethoxy)propyl, methacryloyloxyalkyl, acryloyloxyalkyl, carboxylalkyl groups such as 3-carboxypropyl, 10-carboxydecyl.

[0140] Specific examples of suitable silane crosslinking agents (II) having at least three hydroxyl groups and / or hydrolyzable groups per molecule include, but are not limited to, vinyltrimethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane, ethyltrimethoxysilane, propyltriethoxysilane, isobutyltriethoxysilane, isobutyltrimethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, methyltris(isopropoxy)silane or vinyltris(isopropoxy)silane, 3-hydroxypropyl Triethoxysilane, 3-hydroxypropyltrimethoxysilane, 3-(2-hydroxyethoxy)ethyltriethoxysilane, 3-(2-hydroxyethoxy)ethyltrimethoxysilane, chloropropyltriethoxysilane, 3-mercaptopropyltriethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, 2,3-epoxypropyltriethoxysilane, 2,3-epoxypropyltrimethoxysilane, 3,4-epoxybutyltriethoxysilane, 3,4-epoxybutyltrimethoxysilane, 4,5-epoxypentyltriethoxysilane 4,5-Epoxypentyltrimethoxysilane, 2-glycidoxyethyltriethoxysilane, 2-glycidoxyethyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 4-glycidoxybutyltriethoxysilane, 4-glycidoxybutyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 3-(3,4-epoxycyclohexyl)ethyltriethoxysilane, aminopropyltriethoxysilane Alkane, aminopropyltrimethoxysilane, N-methylaminopropyltriethoxysilane, N-methylaminopropyltrimethoxysilane, N-butylaminopropyltrimethoxysilane, N,N-dibutylaminopropyltriethoxysilane, 3-(2-aminoethoxy)propyltriethoxysilane, methacryloyloxypropyltriethoxysilane, tris(3-triethoxysilylpropyl)isocyanurate, acryloyloxypropyltriethoxysilane, 3-carboxypropyltriethoxysilane, and 10-carboxydecyltriethoxysilane.

[0141] In another embodiment, component (II) may be a bipodial silane, i.e., a silyl functional molecule having at least two silyl groups, each silyl group having at least one and at most three hydrolyzable groups, alternatively each silyl group having at least two hydrolyzable groups, wherein the silyl groups are separated by a polymer backbone. The polymer backbone may be an organic polymer backbone, i.e., component (II) may include organic-based polymers with silyl-terminated groups, such as silyl polyethers, silyl acrylates, and silyl-terminated polyisobutylene. In the case of silyl polyethers, the polymer chain is based on polyoxyalkylene units. Such polyoxyalkylene units preferably comprise repeating oxyalkylene units (-C... n H 2nA linear predominantly oxidized olefin polymer composed of -O-) is formed, the polymer being composed of an average formula (-C n H 2n -O-) y The expression indicates that n is an integer from 2 to 4 (inclusive), and y is an integer of at least four. Similarly, the viscosity will be ≤1000 mPa·s at 25°C, alternatively 250 mPa·s to 1000 mPa·s at 25°C, alternatively 250 mPa·s to 750 mPa·s at 25°C, and will have a suitable number-average molecular weight for each polyoxyethylene polymer block present. As mentioned above, the viscosity can be measured using any suitable apparatus, such as the Modular Compact Rheometer (MCR) 302 from Antonpaght GmbH, Graz, Austria, using the most suitable settings and plates for the viscosity in question. Furthermore, the oxyethylene units need not all be identical in the polyoxyethylene monomer, but can differ between units. The polyoxyethylene blocks or polymers may, for example, be composed of ethylene oxide units (-C2H4-O-); propylene oxide units (-C3H6-O-); or butene oxide units (-C4H8-O-); or mixtures thereof.

[0142] In the case of such organic-based crosslinking agents, the molecular structure can be linear, branched, cyclic, or macromolecular, i.e., organic polymer chains with alkoxy-functionalized end groups.

[0143] In one embodiment, the bipod silane can be a polymer containing two silyl groups, each silyl group containing at least one hydrolyzable group, such as those described below:

[0144] (R 7 O) m (Y 1 ) 3-m –Si(CH2) x –((NHCH2CH2) t -Q(CH2) x ) s -Si(OR 7 ) m (Y 1 ) 3-m

[0145] Where R 7 C 1-10 alkyl group, Y 1 It is an alkyl group containing 1 to 8 carbons.

[0146] Q is a chemical group containing a heteroatom with a lone pair of electrons, such as an amine, N-alkylamine, or urea; each x is an integer from 1 to 6, t is 0 or 1, each m is independently 1, 2, or 3, and s is 0 or 1.

[0147] Suitable examples of bipodysilanes include 1,6-bis(trimethoxysilyl)hexane (or hexamethoxydimethsilylhexane), bis(trialkoxysilyl)amine, bis(dialkoxysilyl)amine, bis(trialkoxysilyl)N-alkylamine, bis(dialkoxysilyl)N-alkylamine, bis(trialkoxysilyl)urea, bis(dialkoxysilyl)urea, bis(3-trimethoxysilylpropyl)amine, bis(3-triethoxysilylpropyl)amine, and bis(4-trimethoxysilylbutyl)amine.

[0148] Bis(4-triethoxysilylbutyl)amine, bis(3-trimethoxysilylpropyl)N-methylamine, bis(3-triethoxysilylpropyl)N-methylamine, bis(4-trimethoxysilylbutyl)N-methylamine, bis(4-triethoxysilylbutyl)N-methylamine, bis(3-trimethoxysilylpropyl)urea, bis(3-triethoxysilylpropyl)urea, bis(4-trimethoxysilylbutyl)urea, bis(4-triethoxysilylbutyl)urea, bis(3-dimethoxymethylsilylpropyl)amine, bis(3-diethoxymethylsilylpropyl)amine, bis(4-dimethoxymethylsilylbutyl)amine, bis(4-diethoxymethylsilylbutyl)amine, bis(4-diethoxymethylsilylbutyl)amine

[0149] bis(3-dimethoxymethylsilylpropyl)N-methylamine,

[0150] bis(3-diethoxymethylsilylpropyl)N-methylamine,

[0151] bis(4-dimethoxymethylsilylbutyl)N-methylamine,

[0152] Bis(4-diethoxymethylsilylbutyl)N-methylamine, bis(3-dimethoxymethylsilylpropyl)urea, bis(3-diethoxymethylsilylpropyl)urea, bis(4-dimethoxymethylsilylbutyl)urea

[0153] Bis(4-diethoxymethylsilylbutyl)urea, bis(3-dimethoxyethylsilylpropyl)amine,

[0154] bis(3-diethoxyethylsilylpropyl)amine, bis(4-dimethoxyethylsilylbutyl)amine,

[0155] bis(4-diethoxyethylsilylbutyl)amine, bis(3-dimethoxyethylsilylpropyl)N-methylamine, bis(3-diethoxyethylsilylpropyl)N-methylamine, bis(4-dimethoxyethylsilylbutyl)N-methylamine

[0156] Bis(4-diethoxyethylsilylbutyl)N-methylamine, bis(3-dimethoxyethylsilylpropyl)urea, bis(3-diethoxyethylsilylpropyl)urea, bis(4-dimethoxyethylsilylbutyl)urea and / or

[0157] Bis(4-diethoxyethylsilylbutyl)urea; bis(triethoxysilylpropyl)amine, bis(trimethoxysilylpropyl)amine, bis(trimethoxysilylpropyl)urea, bis(triethoxysilylpropyl)urea, bis(diethoxymethylsilylpropyl)N-methylamine; di- or trialkoxysilyl-terminated polydialkylsiloxanes, di- or trialkoxysilyl-terminated polyarylalkylsiloxanes, di- or trialkoxysilyl-terminated polypropylene oxides, polyurethanes, polyacrylates; polyisobutylene; di- or triacetoxysilyl-terminated polydialkyl; polyarylalkylsiloxanes; di- or trioxime-silyl-terminated polydialkyl; polyarylalkylsiloxanes; di- or triacetoneoxy-terminated polydialkyl or polyarylalkyl. Component (II) may also contain any combination of two or more of the above.

[0158] Other suitable silicon-containing compounds having at least three hydroxyl groups and / or hydrolyzable groups per molecule include, for example, 1,3,5-tris(trialkoxysilylalkyl)isocyanurates, such as 1,3,5-tris(trialkoxysilylalkyl)isocyanurates having the following structure:

[0159]

[0160] Each R 5 They may be the same or different and are divalent alkylene groups having 2 to 10 carbons, alternatively 2 to 6 carbons, or alternatively 2 to 5 carbons, and each R 6 The same or different and being an alkyl group having 1 to 10 carbons, alternatively 1 to 6 carbons, alternatively 1 to 4 carbons, alternatively a methyl group or an ethyl group. An example is tri-(trimethoxysilylpropyl)isocyanurate as described below, wherein each R... 5 It is a propylene group and each R 6 It is a methyl group.

[0161]

[0162] One or more crosslinking agents (II) having at least 3 hydroxyl groups and / or hydrolyzable groups per molecule are present in an amount of 0.1% to 5% by weight of the composition, in an amount of 0.5% to 4% by weight of the composition, or alternatively in an amount of 1% to 3.5% by weight of the composition.

[0163] One or more reinforcing fillers (III)

[0164] One or more reinforcing fillers identified herein as component (III) may be, for example, selected from precipitated silica, pyrolytic silica, precipitated calcium carbonate, or mixtures of two or more thereof. Typically, the surface area of ​​reinforcing filler (III), as measured according to the BET method (ISO 9277:2010), is at least 15 m² for precipitated calcium carbonate. 2 / g, another 15m site 2 / g to 50m 2 / g, another 15m site 2 / g to 25m 2 / g.

[0165] According to the BET method (ISO 9277:2010), the typical surface area of ​​silica-reinforced fillers is at least 50 m². 2 / g. In the case of high surface area pyrolytic silica and / or high surface area precipitated silica, the surface area of ​​these high surface area pyrolytic silica and / or high surface area precipitated silica can be 75m² as measured according to the BET method (ISO 9277:2010). 2 / g to 400m 2 / g, or alternatively, 100m as measured according to the BET method (ISO 9277:2010). 2 / g to 300m 2 / g.

[0166] The reinforcing filler (III) may be hydrophobically treated, for example, with one or more aliphatic acids (e.g., fatty acids such as stearic acid, or fatty acid esters such as stearates), or with organosilanes, organosiloxanes, or organosilazanes such as hexaalkyldisilazanes or short-chain siloxane diols, so that the filler is hydrophobic and therefore easier to handle and to obtain a homogeneous mixture with other binder components. Specific examples of organosilanes, organosiloxanes, or organosilazanes include, but are not limited to, silanol-terminated trifluoropropylmethylsiloxane, silanol-terminated vinylmethyl (ViMe)siloxane, silanol-terminated methylphenyl (MePh)siloxane, liquid hydroxydimethyl-terminated polydiorganosiloxane containing an average of 2 to 20 repeating units of diorganosiloxane per molecule, hydroxydimethyl-terminated phenylmethylsiloxane, hexaorganodisilazane such as hexamethyldisilazane, divinyltetrasiloxane, etc. Methyldisiloxanes; hexaorganodisilazanes, such as hexamethyldisilazane (HMDZ), divinyltetramethyldisilazane and tetramethylbis(trifluoropropyl)disilazane; hydroxydimethyl-terminated polydimethylmethylvinylsiloxanes, octamethylcyclotetrasiloxanes and silanes, including but not limited to methyltrimethoxysilane, dimethyldimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, trimethylchlorosilane, dimethyldichlorosilane, trichloromethylsilane.

[0167] The surface treatment of the filler makes it easily wettable by component (I). These surface-modified fillers are preferably in a finely divided form, do not clump, and can be uniformly incorporated into the silicone polymer (I). This results in improved room-temperature mechanical properties of the uncured composition. When mixed with component (I), the filler can be pretreated or can be treated in situ. A small amount of water can be added together with the silica treatment agent as a processing aid.

[0168] Depending on the selected filler, reinforcing filler (III) may be present in an amount from 2.5 wt% to 60 wt.% of the composition. When the selected filler is precipitated silica and / or pyrolytic silica or a combination thereof, the inorganic filler (III) is present in the range of about 5.0 wt% to 35 wt% of the composition, alternatively 5 wt% to 30 wt% of the composition, or alternatively 5 wt% to 25 wt% of the composition. However, when the reinforcing filler (III) is precipitated calcium carbonate, the composition will tend to contain a larger wt% of the composition, for example, 25 wt% to 60 wt% of the composition, alternatively 30 wt% to 60 wt% of the composition, or alternatively 35 wt% to 55 wt% of the composition. When component (III) is a mixture of silica and precipitated calcium carbonate, the wt% will generally be between these values.

[0169] Catalysts containing tin(IV)-based compounds

[0170] Component (IV) contains a condensation catalyst, which increases the rate of curing of the composition.

[0171] Component (d) tin (iv) catalyst can be any suitable tin (iv)-based condensation-curing catalyst. Examples of suitable tin (iv)-based catalysts include tin trifluoromethanesulfonate and dialkyltin compounds selected from dimethyltin di-2-ethylhexanoate, dimethyltin dilaurate, dibutyltin diacetate (DBTDA), dibutyltin di-2-ethylhexanoate, dimethyltin dineodecanate (DMTDN), dioctyltin dineodecanate (DOTDN), dibutyltin dioctanoate, dibutyltin di-2,2-dimethyloctanoate, dibutyltin octanoate, and dilaurate. Di-n-butyltin (DBTDL), di-n-butyltin distearate, di-n-butyltin dimaleate, di-n-butyltin dioleate, di-n-octyltin di-2-ethylhexanoate, di-n-octyltin di-2,2-dimethyloctanoate, di-n-octyltin dimaleate, di-n-octyltin dilaurate (DOTDL), di-n-butyltin oxide, methyl phenyltin trioctanoate, tin butyrate, butyltin tri-2-ethylhexanoate, tin naphthenate, isobutyltin tricerate, tin octanoate, triethyltin tartrate, and di-n-octyltin oxide. The amount of the tin (iv)-based condensation catalyst is from 0.001 wt.% to 0.1 wt.% (inclusive) of the composition.

[0172] Optional additives

[0173] Optional additives may be used if necessary. These may include non-reinforcing fillers, pigments, chain extenders, tackifiers, rheology modifiers, curing modifiers, desiccants, extenders, flame retardants, plasticizers, end-capping agents, anti-aging additives, UV absorbers, antioxidants, light stabilizers, fungicides and / or biocides, and combinations thereof. It should be understood that some of these additives may be included in more than one list of additives. Such additives will have the ability to function in the different ways involved.

[0174] Unreinforced packing

[0175] In addition to component (III) of this article, non-reinforcing fillers that may be used include alumina, calcium sulfate (anhydrite), gypsum, nepheline, syenite, quartz, calcium sulfate, magnesium carbonate, heavy calcium carbonate, clays such as kaolin, alumina trihydrate, magnesium hydroxide (brucite), graphite, copper carbonate such as malachite, nickel carbonate such as malachite, barium carbonate such as barite, and / or strontium carbonate such as strontium sapphire.

[0176] Alumina, silicates selected from the group consisting of: olivine; garnet; aluminosilicates; cyclosilicates; chain silicates; and platy silicates. Olivine includes silicate minerals such as, but not limited to, forsterite and Mg₂SiO₄. Garnet includes ground silicate minerals such as, but not limited to, pyrope; Mg₃Al₂Si₃O₄. 12 Grossular garnet and Ca2Al2Si3O 12 Aluminosilicates include ground silicate minerals such as, but not limited to, sillimanite; Al2SiO5; mullite; 3Al2O3.2SiO2; kyanite; and Al2SiO5.

[0177] Cyclic silicates include silicate minerals, such as, but not limited to, cordierite and Al3(Mg,Fe)2[Si4AlO] 18 Chain silicates include ground silicate minerals, such as, but not limited to, wollastonite and Ca[SiO3].

[0178] Flaky silicates include silicate minerals, such as, but not limited to, mica; K2AI 14 [Si6Al2O 20 (OH)4; pyrophyllite; Al4[Si8O 20 (OH)4; Talc; Mg6[Si8O 20 (OH)4; serpentine, for example asbestos; kaolinite; Al4[Si4O] 10 ](OH)8; and vermiculite.

[0179] Such additional fillers can also be hydrophobically treated in the same manner as component (III) described above. When present, unreinforced fillers tend to replace some components (III), so that when component (III) is reinforced with precipitated calcium carbonate and unreinforced fillers are also present in the composition, the total amount of precipitated calcium carbonate and unreinforced fillers will still not exceed 60% by weight of the composition. In one embodiment of the composition, when component (III) is precipitated calcium carbonate, the composition also contains heavy calcium carbonate. When present, unreinforced fillers can be present in amounts greater than 0% by weight to 25% by weight of the composition.

[0180] pigment

[0181] When present, pigments and / or colorants can be colored, white, black, metallic, and luminescent, such as fluorescent and phosphorescent. Pigments are used to color the composition as needed. Any suitable pigment that is compatible with the compositions described herein can be utilized. One-part room-temperature vulcanizable (RTV) silicone compositions may contain white pigments and / or colored (non-white) fillers, such as carbon black.

[0182] Typically, pigments and / or colorants, when in particulate form, have an average particle size in the range of 10 nm to 50 μm, preferably in the range of 40 nm to 2 μm. When present, pigments and / or colorants are present in the range of 2% by weight, alternatively 3% by weight, alternatively 5% by weight to 20% by weight of the composition.

[0183] rheology modifiers

[0184] Rheology modifiers that can be incorporated into a single-part room-temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst include silicone organic copolymers, such as those of polyether- or polyester-based polyols as described in EP0802233; nonionic surfactants selected from the group consisting of polyethylene glycol, polypropylene glycol, ethoxylated castor oil, oleic acid ethoxylates, alkylphenol ethoxylates, copolymers of ethylene oxide and propylene oxide, and silicone polyether copolymers; and silicone glycols. For some systems, these rheology modifiers, particularly copolymers of ethylene oxide and propylene oxide and silicone polyether copolymers, can enhance adhesion to substrates, especially plastic substrates.

[0185] Tackifier

[0186] The single-component room temperature vulcanizable (RTV) silicone composition described above may also contain an aminosilane tackifier having two or three hydroxyl or alkoxy groups per molecule. The aminosilane tackifier having two or three hydroxyl or alkoxy groups per molecule may include:

[0187] R 10 k (R 11 O) 3-k Si-Z 2 -N(H)-(CH2) m' -NH2

[0188] Where R 10 It is an alkyl group containing 1 to 10 carbon atoms; each R 11 They can be the same or different, and are H or R. 10 Z 2 It is a straight-chain or branched alkylene group having 2 to 10 carbon atoms, m' is 2 to 10, and k is zero or 1.

[0189] R 10 It is an alkyl group containing 1 to 10 carbon atoms, or R 10 An alkyl group containing 1 to 6 carbon atoms, or alternatively R 10 It is a methyl group or an ethyl group. Each R 11They can be the same or different, and each R 11 They can be the same or different, and can be H, R, or R. 10 Alternatively, each R 11 For R 10 In an alternative solution, all R 11 The groups are all the same. When R 11 When the functional groups are the same, it is preferable that they are methyl or ethyl groups. 2 It is a straight-chain or branched alkylene group having 2 to 10 carbons, or alternatively 2 to 6 carbons, such as Z. 2 It can be a propylene group, a butylene group, or an isobutylene group. There can be 2 to 10 m' groups. In one alternative, m' can be 2 to 6; in another alternative, m' can be 2 to 5; in yet another alternative, m' can be 2 or 3; alternatively, m' is 2.

[0190] Other tackifiers that may be used include N-(3-(trimethoxysilyl)propyl)butylamine, bis(trimethoxysilyl)propylamine, bis[3-(triethoxysilyl)propyl]amine, bis[3-(triethoxysilyl)propyl]amine, aminopropyltriethoxysilane, and aminopropyltrimethoxysilane.

[0191] When present, the tackifier is present in an amount of 0.1% to 3.75% by weight of the composition, alternatively in an amount of 0.1% to 2.5% by weight of the composition, alternatively in an amount of 0.1% to 2.0% by weight of the composition, alternatively in an amount of 0.2% to 1.0% by weight of the composition.

[0192] UV and / or light stabilizers

[0193] For illustrative purposes, UV and / or light stabilizers may include benzotriazole, ultraviolet absorbers, and / or hindered amine light stabilizers (HALS), such as those from Ciba Specialty Chemicals Inc. Product series.

[0194] biocides

[0195] If necessary, a biocide may be used in the composition. The term "biocide" is intended to include bactericides, fungicides, and algaecides, etc.

[0196] The single-component room temperature vulcanizable (RTV) silicone composition described above can be prepared by mixing all the components together. Preferably, once mixed, the composition is sealed in one or more moisture-proof containers and stored unless used immediately. In one embodiment, the filler (III) and / or pigment are first mixed into the polymer (I) in the presence of the filler, optionally in combination with a hydrophobic treatment agent, such that the filler and optionally the pigment can be hydrophobically treated in situ during mixing into the polymer.

[0197] Once the filler has been thoroughly mixed into the polymer (and hydrophobically treated if necessary), the remaining components are added in any suitable order to prepare the complete composition.

[0198] For example, in one method, a method for preparing a single-part room temperature vulcanizable (RTV) silicone composition may include the following steps:

[0199] In the preparation of formulations 1 and 2, polymer 1 was alkoxy-terminated in a high-speed mixer using the following method:

[0200] 1) First, a suitable end-capping catalyst (such as 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD)) is prepared by dissolving the TBD end-capping catalyst in methyltrimethoxysilane.

[0201] A 1% by weight solution of methyltrimethoxysilane was prepared, and then vinyltrimethoxysilane was added to provide a capping catalyst solution.

[0202] 2) Mix the polymer with any plasticizer (if present);

[0203] 3) The end-capping catalyst mixture is then introduced into the mixture obtained in step 2 above, and the mixture is stirred at room temperature for a predetermined time period (e.g., 10 to 45 minutes).

[0204] Then, the following additional steps are used to prepare a single-part organopolysiloxane elastomer composition utilizing the product of the above-described alkoxy-terminated reaction:

[0205] 4) Premix the condensation curing catalyst and any tackifier (if present) (e.g., N-[3-(trimethoxysilyl)propyl]ethylenediamine or 3-(trimethoxysilyl)propylamine).

[0206] (if necessary) to form mixture 2;

[0207] 5) Introduce mixture 2 into the mixer and mix all the substances for another 5 minutes;

[0208] 6) Then gradually add the packing material into the tank;

[0209] 7) After thoroughly mixing the filler, add hexamethyldisilazane; and

[0210] 8) The composition is then further mixed under vacuum for 10 minutes, after which the final single-part organopolysiloxane elastomer composition is packaged.

[0211] Due to the presence of the aforementioned alcohols (especially methanol) and tin catalysts, the polymer is susceptible to polymer backbone reversal and / or easy degradation, resulting in a very poor shelf life. Hexamethyldisilazane (HMDZ) is used as a methanol scavenger to ensure a better shelf life. However, HMDZ is highly reactive and readily hydrolyzes during storage, producing ammonia. In this case, the use of HMDZ increases the possibility of bubble formation on thermally porous surfaces at 40°C or higher. However, by using a binder composition containing at least 25% by weight of a binder as described herein (e.g., PMMA) as described herein, foaming is significantly reduced.

[0212] In step (iii), a single-part room-temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst can be applied to a continuous elastic adhesive film by any suitable means, such as extrusion, coating, injection, blade coating, and rolling, depending on its viscosity and flowability on the continuous elastic adhesive film. Regardless of the application method, it has been found that when applied on top of an adhesive interlayer, rather than directly applied to a substrate surface at a temperature of 40°C or higher, bubbles are not formed or are formed in a significantly smaller number of bubbles in a standard single-part room-temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst, whereas when the standard single-part room-temperature vulcanizable (RTV) silicone composition is applied directly to a thermally porous substrate surface at a temperature of at least 40°C, where extensive foaming results in very poor adhesion. The reduction in the number and size of air bubbles in cured silicone sealants is beneficial to the construction industry in hot countries where the substrate often reaches temperatures exceeding 40°C in the hottest part of the day due to heat from the sun, etc. Significant air bubble formation with standard sealants has proven to be a major problem in the construction industry because it causes surface blistering between the cured / cured sealant and the substrate surface, resulting in poor adhesion between them, which is unacceptable.

[0213] Another advantage of this method is that, compared to directly applying a single-component room temperature vulcanizable (RTV) silicone composition to a thermally porous substrate at 40°C, the continuous elastic adhesive film protects the single-component RTV silicone composition and insulates it from the temperature of the substrate, thus providing the user with increased working time. These compositions tend to cure very rapidly at the relevant temperature because, after application of the single-component RTV silicone composition to the thermally porous substrate, exposure to atmospheric moisture causes it to undergo accelerated curing.

[0214] A sealed porous substrate, which is a product of the above method, is also provided. The single-component room temperature vulcanizable (RTV) silicone composition used herein can be used as a sealant or adhesive, or as a weatherproof sealant or professional caulking agent or adhesive and sealant for residential and industrial frame panels. Example

[0215] All corporate test methods (CTMs) mentioned in this article are publicly available from Dow Silicones Ltd. upon request.

[0216] Various adhesives and primers were evaluated for use as, or for, in continuous elastic adhesive films as described above. The commercial adhesives used in the examples are:

[0217] DOWSIL TM 1200 OS primer is a primer for silicone adhesives and sealants. It is a colorless liquid with a viscosity of 1 mPa·s at 23°C, a closed-cup flash point of 27°C, a VOC of 76 g / L, and a specific gravity of 0.84 at 23°C (all values ​​are from the datasheet). It contains no polymethyl methacrylate.

[0218] DOWSIL TM Primer-C is a solvent-based silane primer suitable for a variety of applications, with a strength of 800ft. 2 / gallon (16.33m 2 The composition exhibits a non-porous substrate coverage of 0.90 g / L, a color flash point of -4°C, and a VOC content of 1,855 g / L based on the maximum VOCs in the Southern Coast Air Quality Management Zone of California (all values ​​are taken from the datasheet). It contains approximately 5% by weight of a methacrylate polymer in the composition.

[0219] DOWSIL TMArchitectural Primer P is a primer in the form of a proprietary alkoxysilane formulation for use on masonry surfaces in a solvent. It is a clear liquid with a specific gravity of 0.95 (ASTM D 1298), a flash point (closed cup) of 8°C, a sealant application time of 0.5 to 8 hours at 25°C, and a VOC content of 748 g / L based on the maximum VOCs in the Southern Coast Air Quality Management District of California (all values ​​are from datasheets). It contains approximately 20% by weight of polyacrylate in the composition.

[0220] DOWSIL TM Architectural Primer B is a film-forming primer for porous and metallic substrates. It is a transparent liquid with a specific gravity of 0.97 (ASTM D 1298), a flash point (closed cup) of 26°C, a sealant application time of 0.5 to 8 hours at 25°C, and a VOC content of 577 g / L based on the maximum VOCs in the Southern Coast Air Quality Management District of California (all values ​​are from datasheets). It contains approximately 40% by weight of a methacrylate polymer in the composition. Two silicone resins are also used:

[0221] DT silicone resin solution. The DT silicone resin solution used is a clear / turbid solution containing approximately 70% by weight of DT silicone resin (CTM 0208) in toluene, with a viscosity of approximately 950 mPa·s at 25°C (CTM 0004). DT silicone resin is composed of D units and T units.

[0222] D=(R 4 R 5 SiO 2 / 2 ),T=(R 6 SiO 3 / 2 )

[0223] D unit containing 0.65 mole fraction (where R) 4 and R 5 It is a methyl group), 0.09 mole fraction of T unit (where R 6 (is a methyl group) and 0.26 mole fraction of T units (where R is a methyl group) and T units (where R is a methyl group). 6 (It is a phenyl group).

[0224] In addition, an adhesive solution was also prepared:

[0225] Polymethyl methacrylate (PMMA) solution. The PMMA solution is a 30% by weight solution of polymethyl methacrylate in 70% by weight toluene. The PMMA used in this example and the membrane is PLEXIGLAS from ROHM GmbH in Darmstadt, Germany. TM 6N.

[0226] All commercial primers used were available from Dow Silicones, Inc. in Midland, Michigan, USA.

[0227] In the first series of examples and comparative examples, a composition layer of a continuous elastic adhesive film was first coated onto a granite substrate at a temperature of about 50°C before top coating with a single-part room temperature vulcanizable (RTV) silicone composition.

[0228] Two single-component room temperature vulcanizable (RTV) silicone compositions were prepared using the method described in WO2022041180, but stabilization was not required for the immediate preparation of the sealant compositions. The components used to prepare the sealant compositions are listed in Table 1 below:

[0229] Table 1. Components used in preparing sealant formulations 1 and 2

[0230]

[0231]

[0232] Polymer 1 shown in Table 1 is a dimethylsilanol-terminated polydimethylsiloxane with a viscosity of approximately 50,000 mPa·s, which is alkoxy-terminated during the reaction described below. The viscosity of Polymer 1 can be measured by any suitable method, such as according to corporate test method CTM 0050, which is publicly available and based on ASTM D 1084-16 Method B, using a Brookfield DV-III Ultra rheometer equipped with a conical plate geometry, at 5 rpm for 2 minutes using a mandrel 52.

[0233] TBD is 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

[0234] Polymer 2 is a trimethyl-terminated polydimethylsiloxane with a viscosity of approximately 100 mPa·s at 25°C, which can be DOWSIL TM 200 fluid was purchased commercially from Dow Silicones, Midland, Michigan, USA;

[0235] The GCC used was type 203A, which was commercially available from Qunxin Powder Technology C. Ltd. of Yangzhou, Jiangsu, Province, China.

[0236] The pyrolytic silica used can be obtained from Wacker via HDK. TM V15D purchased commercially.

[0237] In the preparation of formulations 1 and 2, polymer 1 was alkoxy-terminated in a high-speed mixer using the following method:

[0238] 1) First, a 1% by weight solution of TBD end-capping catalyst in methyltrimethoxysilane was prepared by dissolving the TBD end-capping catalyst in methyltrimethoxysilane, and then vinyltrimethoxysilane was added to provide the end-capping catalyst solution.

[0239] 2) Mix the polymer and plasticizer together in a 10-liter Turello mixer at approximately 400 rpm;

[0240] 3) Then the end-capped catalyst mixture is introduced into the mixture obtained in step 2 above, and the mixture is stirred at 400 rpm for 15 minutes at room temperature;

[0241] To produce a one-component organopolysiloxane elastomer composition using the product of the above alkoxy-terminated reaction, the following further steps are performed: -

[0242] 4) The condensation curing catalyst and tackifier N-[3-(trimethoxysilyl)propyl]ethylenediamine used for formulation 1 and 3-(trimethoxysilyl)propylamine used for formulation 2 are premixed to form mixture 2;

[0243] 5) Introduce mixture 2 into the mixer and mix all the substances for another 5 minutes;

[0244] 6) Then add the filler. This consists of calcium carbonate and silica from formulation 1, and silica only from formulation 2. Gradually add the filler to the tank;

[0245] 7) After thoroughly mixing the filler, add hexamethyldisilazane; and

[0246] 8) The composition is then further mixed under vacuum for 10 minutes, after which the final single-part organopolysiloxane elastomer composition is packaged.

[0247] To improve the potential level of foaming, the single-component room temperature vulcanizable (RTV) silicone composition was aged at 50°C for two weeks prior to the evaluation, as it has been determined that the foaming effect is most pronounced if the applied sealant composition has been stored for a period of time before use.

[0248] The granite substrate was cleaned with isopropyl alcohol and then heated to approximately 50°C. The adhesive composition to be tested was then applied by brush and dried by evaporating the solvent to obtain an adhesive-coated granite substrate. The adhesive-coated granite substrate was then heated in an oven for 30 minutes to ensure it was at least 50°C when the sealant composition was applied. The adhesive-coated granite substrate was removed from the oven, and the sealant composition was applied on top of the adhesive coating. It was then immediately returned to the oven to maintain the sealant at approximately 50°C for the curing process. After curing, each sample was first visually evaluated to observe for any noticeable surface blistering on the sealant surface. The sealant layer was then cut from one side to check for air bubbles at the interface between the sealant and the substrate. Results for formulation 1 are provided in Tables 2a and 2b, and results for formulation 2 are provided in Tables 3a and 3b.

[0249] Table 2a: Bubbling state of Ref. 1 and Comparative Examples C. 1 to 3 using silicone sealant formulation 1

[0250] Ref.1 C.1 C.2 C.3 Adhesive / Film-forming agent / 1200OS Primer C Primer P Polyacrylate content in adhesive / 0 5％ 20％ substrate granite granite granite granite Adhesive film appearance NA Difference Difference Difference Description of the bubbling state Many bubbles Many bubbles Many bubbles Many bubbles Scoring of bubbling state 5 5 5 5

[0251] The scoring criteria for the bubbling state are as follows:

[0252] 1 = No bubbling was observed;

[0253] 2 = Very small bubbles, which have no effect on adhesion;

[0254] 3 = Some bubbling may negatively affect adhesion;

[0255] 4. Obvious bubbling was observed, which has a negative impact on adhesion;

[0256] 5 = Very noticeable bubbling was observed, with almost no adhesion (easily peeled off by hand).

[0257] The same standards were used for all embodiments and comparative examples. In Reference 1, the sealant composition of Table 1 (Formulation 1) was applied directly to the granite surface, and thus, as expected, a high level of bubbling was observed. It was also noted that, as expected, the sealant composition (Formulation 1) had poor adhesion to the granite and was easily peeled off after curing.

[0258] In comparative examples C.1, C.2, and C.3, each substrate was coated with a primer; in C.1, it was DOWSIL. TM 1200 OS primer, which is binder-free, is DOWSIL in C.2. TM Primer-C, which contains approximately 5% by weight polymethyl methacrylate, and in C.3 it is DOWSIL TMArchitectural primer P contains approximately 20% by weight of polymethyl methacrylate. In these cases, given the lack of or low levels of binder content, the primer coating is very thin, ranging from approximately 5 μm to 20 μm in thickness. The thickness of a standard primer (non-film-forming) coating applied to a substrate is typically no more than 12.5 μm, which is much thinner than the continuous elastomeric binder film layer described herein, which is at least 30 μm but typically up to approximately 50 μm. Although the coating thickness was not measured, the thickness of a standard primer (non-film-forming) coating applied to a substrate is typically no more than 12.5 μm, which is much thinner than the continuous elastomeric binder film layer described herein, which is at least 20 μm but typically up to approximately 30 μm. The coating was observed to be discontinuous on porous substrates and was therefore identified as poor in Table 2a. For general primers, especially when some solvents with low boiling points are used in the formulation, it was found that while they can enhance adhesion between the substrate and the sealant, they are essentially insufficient to block the moisture channels through the capillaries in the substrate at elevated temperatures.

[0259] Although not quantified, the presence of a continuous adhesive film between the hot granite surface and the single-component room temperature vulcanizable (RTV) silicone composition (Formulation 1) in C.1 to 3 appears to result in better adhesion between the hot granite and the resulting silicone sealant at approximately 50°C; however, there is no difference or minimal difference regarding bubbling. This teaches that preventing or minimizing bubbling is not about applying the primer itself to the substrate surface.

[0260] Table 2b: Bubbling status of sealant formulations 1 (Ex.1 to Ex.3)

[0261]

[0262]

[0263] In Table 2b, Res t It refers to flexibility.

[0264] In contrast, in Ex.1, Ex.2, and Ex.3, the adhesive compositions used for coating granite surfaces contain 30% by weight of PMMA Sol. n DOWSIL TMArchitectural primer B contains 40% by weight of binder and 70% by weight of DT resin binder. In each case, when applied to the binder composition layer, Ex.1, Ex.2, and Ex.3 significantly reduced foaming in the single-component room temperature vulcanizable (RTV) silicone composition (Formulation 1). Therefore, when comparing the results in Table 2a with those in Table 2b, it can be seen that when Formulation 1 (calcium carbonate-filled alkoxy sealant) is applied to a 50°C granite substrate, many bubbles appear in the cured sealant if no binder composition layer is used or if a binder composition layer with a binder content of less than 30% is used (Table 2a), while the foaming problem is significantly reduced when a binder composition containing a larger binder content is used (Ex.1 to 3).

[0265] The sealant compositions of formulation 2 in Table 1 above were then used to prepare a second series of examples, comparing them with Reference Example Ref. 2 and Comparative Examples C.4 to C.6. These were directly compared with Examples 4 to 6, in which PMMA solution, primer B, and DT silicone resin were used as adhesive compositions, respectively. The results are described in Tables 3a and 3b below.

[0266] Table 3a: Bubbling state of Ref. 2 containing sealant formulation 2 and Comparative Examples 4 to 6

[0267] Ref.2 Comparative Example 4 Comparative Example 5 Comparative Example 6 Adhesive / Film-forming agent / OS-1200 Primer C Primer P Polyacrylate content in adhesive / 0 5％ 20％ substrate granite granite granite granite Adhesive film appearance NA Difference Difference Difference Description of the bubbling state Many bubbles Many bubbles Many bubbles Many bubbles Scoring of bubbling state 5 5 5 5

[0268] Table 3b: Foaming status of Examples Ex.4 to Ex.6 containing sealant formulation 2

[0269] Ex4 Ex5 Ex6 Primer / Film-forming agent PMMA solution Primer B DT resin polyacrylate or resin content 30％ 40％ 70％ substrate granite granite granite Adhesive film appearance <![CDATA[Res t ]]> <![CDATA[Res t ]]> <![CDATA[Res t ]]> Description of the bubbling state Some bubbles A few bubbles A few bubbles Scoring of bubbling state 3 2 2

[0270] Similar results were obtained when Ref. 2 and Comparative Examples C. 4 to 6 as shown in Table 3a were compared with Ex. 4, Ex. 5, and Ex. 6 of sealant formulation 2 as shown in Table 1 in each case. In each case, Ex. 4, Ex. 5, and Ex. 6 significantly reduced bubbling in the single-component room temperature vulcanizable (RTV) silicone composition (formulation 2) when applied to the adhesive composition layer. Therefore, when comparing the results in Table 3a with those in Table 3b, it can be seen that when formulation 2 is applied to a granite substrate at approximately 50°C, many bubbles appear in the cured sealant if no adhesive composition layer is used or if an adhesive composition layer with an adhesive content of less than 30% is used (Table 3a), while the bubbling problem is significantly reduced when an adhesive composition containing a larger adhesive content is used (Ex. 4 to 6).

Claims

1. A method for applying a monopartic room-temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst to a thermally porous substrate at a temperature of at least 40°C, the method comprising the steps of: (i) Applying an aqueous or solvent-based adhesive composition to the surface of a thermally porous substrate at a temperature of at least 40°C; The aqueous or solvent-based adhesive composition comprises at least 25% by weight of the adhesive, wherein the adhesive is selected from (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinylpyrrolidone, polyvinyl butyral, polyurethane, and silicone resins having the following structures, or mixtures of two or more thereof. M (a) D (b) T (c) Q (d) Where a, b, c, and d are mole fractions, 0 <a<1,b≥0,c≥0,d≥0,c+d> 0, a+b+c+d=1 and a+d≠1; (ii) Drying and / or curing the aqueous or solvent-based adhesive composition to allow the adhesive to coalesce and form a continuous, elastic adhesive film on the thermally porous substrate, and then... (iii) Applying a single-part room temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst to the surface of the continuous elastic adhesive film and allowing it to cure.

2. The method according to claim 1, wherein the thermally porous substrate is selected from stone, marble, brick, concrete, cement and other cementitious substrates.

3. The method according to claim 1 or 2, wherein the solvent is selected from naphtha, toluene, heptane, methyl isobutyl ketone, butyl acetate and xylene, other solvent oils, tert-butyl acetate, methyl acetate, ethyl acetate, n-butyl acetate, methyl formate, ethyl formate and any combination thereof.

4. The method according to claim 1 or 2, wherein the solvent-based adhesive composition comprises a non-aqueous solvent and 25% to 75% by weight of the adhesive in the composition.

5. The method according to claim 1 or 2, wherein the solvent-based adhesive composition is a primer or modified primer containing 25% to 75% by weight of the adhesive in the composition.

6. The method according to claim 1 or 2, wherein the adhesive is a (meth)acrylic resin or a DT silicone resin.

7. A thermally porous substrate that is sealed at a temperature of at least 40°C, said thermally porous substrate being the product of the method according to claim 1.

8. A thermally porous substrate sealed at a temperature of at least 40°C, said thermally porous substrate being coated with a cured layer of a single-partial room-temperature vulcanizable (RTV) silicone composition, said cured layer being obtained or obtainable by the following steps: (i) Applying an aqueous or solvent-based adhesive composition to the surface of a thermally porous substrate at a temperature of at least 40°C; The aqueous or solvent-based adhesive composition comprises at least 25% by weight of the adhesive, wherein the adhesive is selected from (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinylpyrrolidone, polyvinyl butyral, polyurethane, and silicone resins having the following structures, or mixtures of two or more thereof. M (a) D (b) T (c) Q (d) Where a, b, c, and d are mole fractions, 0 <a<1,b≥0,c≥0,d≥0,c+d> 0, a+b+c+d=1 and a+d≠1; (ii) Drying and / or curing the aqueous or solvent-based adhesive composition to enable the adhesive to coalesce and form a continuous, elastic adhesive film on the thermally porous substrate, and then... (iii) Applying a single-part room temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst to the surface of the continuous elastic adhesive film and allowing it to cure.

9. The thermally porous substrate sealed at a temperature of at least 40°C according to claim 7 or 8, said thermally porous substrate having a continuous elastic adhesive film at least 30 μm thick.

10. A thermally porous substrate sealed at a temperature of at least 40°C according to any one of claims 7, 8 or 9, wherein the thermally porous substrate is selected from stone, marble, brick, concrete, cement and other cementitious substrates.

11. Use of an aqueous or solvent-based adhesive composition in a method for applying a single-part room-temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin(IV)-based catalyst to a thermally porous substrate at a temperature of at least 40°C, wherein the aqueous or solvent-based adhesive composition comprises at least 25% by weight of the adhesive, said adhesive being selected from (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinylpyrrolidone, polyvinyl butyral, polyurethane, and silicone resins having the following structures, or mixtures of two or more of these. M (a) D (b) T (c) Q (d) Where a, b, c, and d are mole fractions, 0 <a<1,b≥0,c≥0,d≥0,c+d> 0, a+b+c+d=1 and a+d≠1, the method includes the following steps: An aqueous or solvent-based adhesive composition containing at least 25% by weight of the adhesive is applied to the surface of a thermally porous substrate at a temperature of at least 40°C. The aqueous or solvent-based adhesive composition containing at least 25% by weight of the adhesive is dried and / or cured, enabling the adhesive to coalesce and form a continuous elastic adhesive film on the thermally porous substrate; And then A single-part room temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst is applied to the surface of the continuous elastic adhesive film and cured thereon.

12. The use according to claim 11, wherein when cured on a thermally porous substrate at a temperature of at least 40°C, the continuous elastic adhesive film prevents or minimizes the generation of air bubbles in the single-part room temperature vulcanizable (RTV) silicone composition.

13. The method of claim 1 is used for weatherproofing a thermally porous substrate at a temperature of at least 40°C, while preventing or minimizing the generation of air bubbles in the single-component room temperature vulcanizable (RTV) silicone composition during curing at a temperature of at least 40°C.

14. The use according to claim 12 or 13, wherein the thermally porous substrate is selected from stone, marble, brick, concrete, cement and other cementitious substrates.

15. A method for filling a space between a first substrate and a second substrate to create a seal therebetween, wherein at least one of the first substrate and the second substrate is a thermally porous substrate at a temperature of at least 40°C, the seal having a cured layer of a single-component room-temperature vulcanizable (RTV) silicone composition, the method comprising: (i) Applying an aqueous or solvent-based adhesive composition at least partially to the surface of the thermally porous substrate at a temperature of at least 40°C, wherein the aqueous or solvent-based adhesive composition comprises at least 25% by weight of the adhesive, the adhesive being selected from (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinylpyrrolidone, polyvinyl butyral, polyurethane, and silicone resins having the following structures, or mixtures of two or more of these. M (a) D (b) T (c) Q (d) Where a, b, c, and d are mole fractions, 0 <a<1,b≥0,c≥0,d≥0,c+d> 0, a+b+c+d=1 and a+d≠1; (ii) Drying and / or curing the aqueous or solvent-based adhesive composition to enable the adhesive to coalesce and form a continuous elastic adhesive film at least on the thermally porous substrate; And then (iii) Applying a single-part room temperature vulcanizable (RTV) silicone composition comprising an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst to the surface of the continuous elastic adhesive film and allowing it to cure.

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