Method of applying a sealant composition

Abstract

The present invention relates to a process for applying a single part tin catalyzed room temperature vulcanizable (RTV) silicone composition to a hot porous substrate at a temperature of at least 40 DEG C, the method is performed by first applying an aqueous or solvent-based binder composition on the hot porous substrate at a temperature of at least 40 DEG C to produce a continuous elastic binder film prior to applying the single part tin catalyzed room temperature vulcanizable (RTV) silicone composition. Also provided is a thermally porous substrate coated with a cured layer of a single part tin catalyzed room temperature vulcanizable (RTV) silicone composition at a temperature of at least 40 DEG C. The porous substrate may be, for example, a building material such as stone, marble, brick, concrete, cement, and other cementitious substrates.

Description

[0001] The present invention relates to a method of 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-based adhesive composition to the hot porous substrate at a temperature of at least 40°C to produce a continuous elastic adhesive film before applying the one-part tin-catalyzed room temperature vulcanizable (RTV) silicone composition. A hot porous substrate is also provided, which is coated with a cured layer of a one-part tin-catalyzed room temperature vulcanizable (RTV) silicone composition at a temperature of at least 40°C. The 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 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 and thereby crosslink the composition to form, for example, an elastomeric sealant product, typically but not absolutely always in combination with one or more condensation curing catalysts. As required and when desired, one or more additional ingredients, such as reinforcing fillers, non-reinforcing fillers, tackifiers, diluents (e.g., plasticizers and / or extenders), stabilizers, chain extenders, biocides, etc., are also typically incorporated into these compositions. They may be one-part compositions or multi-part compositions, for example two-part compositions.

[0003] One-part condensation-curing silicone compositions are used to produce skin or diffusion-cured silicone elastomers for use as caulks, sealants, encapsulants and / or adhesives. They are generally designed to contain as little water / moisture as possible in the composition, i.e., they are stored in a substantially water-free form to prevent premature curing during storage prior to use. Such one-part condensation-curing silicone compositions are applied to the substrate in a layer that is typically thinner than 15 mm. If such compositions are applied in a layer thicker than 15 mm, this may generally result in uncured material in the depth of the material because moisture diffuses very slowly in very deep portions. Skin or diffusion curing (e.g., moisture / condensation) occurs by forming a cured skin at the composition / air interface after the sealant / encapsulant is applied to the substrate surface. After the surface skin is created, the cure rate depends on the rate at which moisture diffuses from the sealant / encapsulant interface with air to the inside (or core) of the layer of applied silicone composition, as well as the rate at which condensation reaction byproducts / effluent diffuse from the inside (or core) to the outside (or surface) of the material and the gradual thickening of the cured skin over time from the outside / surface to the inside / core. The primary, if not the only, source of moisture in these compositions is inorganic fillers, such as silica when present. The fillers may be rendered anhydrous prior to intermixing with the other ingredients, or water / moisture may be extracted from the mixture during the mixing process to ensure that the resulting sealant composition is substantially anhydrous.

[0004] In contrast, multi-part compositions are designed to cure in the body of, for example, a silicone sealant, once the parts are mixed together and applied to the surface of the substrate. They are stored in at least two parts, but usually two parts, before use to prevent premature curing. In these multi-part compositions, one part contains a filler, which usually contains the moisture required to activate the condensation cure in the body of the product, and the crosslinker and catalyst are in another part. Multiple (e.g., two-part) condensation cure systems, once mixed together, are capable of overall curing even in parts greater than 15 mm in depth. In this case, the composition will cure throughout the body of the material (after mixing). If a surface layer is formed, this only occurs within the first few minutes after application. Soon after, the product will become solid throughout the mass.

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

[0006] N-neutral oxime sealants were developed in the 1960s as a preferred alternative to acetoxy sealants. Oxime sealant compositions rely on a silicon-containing crosslinker having at least 3 oxime groups per molecule, typically a silane having three or four oxime groups per molecule. Such one-part oxime sealants are typically condensation cured using an organotin catalyst. Compositions using oxime crosslinkers produce ketoxime byproducts during cure, the most common of which is methyl ethyl ketoxime (MEKO), an oxime derivative of methyl ethyl ketone.

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

[0008] These by-products are non-corrosive, enabling such sealants to be used, for example, as weathering sealants on building substrates. One of the reasons why the building industry prefers to use 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 texts), and is therefore suitable for use in hot countries without having harmful effects when the substrate surface reaches 40°C or more during a 40°C working day, which can often happen when the substrate is exposed to direct sunlight for several hours during the working day. However, although they are non-corrosive and have other advantages, they are no longer advantageous. This is because MEKO has been identified as a carcinogen 1B chemical under the European REACH regulation. This has led the industry to seek to develop alternatives to oxime sealants.

[0009] From a practical standpoint, the construction industry prefers one-component compositions that eliminate the need to mix the ingredients prior to application and compositions with excellent workability. One alternative that has been developed is a one-part tin-catalyzed room temperature vulcanizable (RTV) alkoxy silicone sealant composition. Such sealants release essentially non-corrosive alcohol byproducts during the curing process.

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

[0011] When the temperature of the substrate is above 40°C, the generation of bubbles in one-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 is generally significant, resulting in surface blistering and poor adhesion. Without being bound by existing theory, it is believed that when these one-part room temperature vulcanizable (RTV) silicone compositions are applied to porous substrates (especially building materials such as stone, marble, brick, concrete, cement and other cementitious substrates that are generally hydrophilic) at elevated temperatures (e.g., above 40°C), as the substrate temperature increases, more and more moisture / water vapor will condense or accumulate at the interface of the one-part room temperature vulcanizable (RTV) silicone composition and the porous substrate, driven by capillary action and the reactivity of moisture with the composition. It is believed that this leads to increasing hydrolysis of the alkoxysilyl groups at the interface and, therefore, to accelerated production of alcohols, especially methanol, at the substrate / composition interface. Typically, the alcohols produced (especially methanol) have a low boiling point at atmospheric pressure, so at elevated temperatures, methanol production is accelerated at the interface, with its production rate gradually exceeding its penetration rate through the bulk composition, resulting in foaming within the cured and ultimately cured composition. The bubbles produced are unacceptable because they increase the volume of the cured product by as much as two or three times compared to an equivalent cured product cured at room temperature. Weatherproof sealing of substrates and other construction processes involving the use of one-part room temperature vulcanizable (RTV) silicone compositions (such as sealing joints between substrates and / or around windows, sashes and frames, and facades, etc.) need to be completed during the working day as and when the work is needed, and waiting for cooler overnight temperatures is not an option for effective work. Therefore, this can be a major problem in the construction industry, especially for countries with hot climates.

[0012] Binders or film formers (hereinafter referred to as binders) are film-forming components of coatings such as paints, which are usually 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 surface of the substrate.

[0013] Provided herein is a method of applying a one-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 thermal porous substrate at a temperature of at least 40°C, the method comprising the steps of:

[0014] (i) treating an aqueous or solvent-based adhesive composition at a temperature of at least 40° C., wherein the aqueous or solvent-based adhesive composition comprises at least 25% by weight of a binder selected from the group consisting of (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinyl pyrrolidone, polyvinyl butyral, polyurethane and a silicone resin having the 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 thereof;

[0017] applying to a surface of a thermally porous substrate;

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

[0019] (iii) applying a one-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 surface of the continuous elastic adhesive film and curing it.

[0020] The porous substrate may be, for example, a building material such as stone, marble, brick, concrete, cement and other cementitious substrates.

[0021] Also provided is a sealed porous substrate as a product of the above method.

[0022] Also provided herein is a thermally porous substrate coated with a cured layer of a one-part room temperature vulcanizable (RTV) silicone composition at a temperature of at least 40° C., the cured layer being obtained or obtainable by the following steps:

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

[0024] A water-based or solvent-based adhesive composition, the water-based or solvent-based adhesive composition comprising at least 25% by weight of the adhesive, the adhesive being selected from (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinyl pyrrolidone, polyvinyl butyral, polyurethane, and a silicone resin having the following structure

[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 thereof;

[0028] applying to a surface of a thermally porous substrate;

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

[0030] (iii) applying a one-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 surface of the continuous elastic adhesive film and curing it.

[0031] This article also provides

[0032] A water-based or solvent-based adhesive composition, the water-based or solvent-based adhesive composition comprising at least 25% by weight of the adhesive, the adhesive being selected from (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinyl pyrrolidone, polyvinyl butyral, polyurethane, and a silicone resin having the following structure

[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 thereof;

[0035] Use in a method for applying a one-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] applying an aqueous or solvent-based binder composition comprising at least 25% by weight of said binder to the surface of the thermally porous substrate at a temperature of at least 40°C;

[0037] drying and / or curing the aqueous or solvent-based binder composition comprising at least 25% by weight of the binder to allow the binder to coalesce and form a continuous elastic binder film on the thermal porous substrate; and then

[0038] A one-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.

[0039] Also provided is a method for filling a space between a first substrate and a second substrate to create a seal therebetween, at least one of the first substrate and the second substrate being a thermally porous substrate at a temperature of at least 40° C., the seal having a cured layer of a one-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, the water-based or solvent-based adhesive composition comprising at least 25% by weight of the adhesive, the adhesive being selected from (meth) acrylic resin, poly (meth) acrylic acid, polyvinyl acetate, polyvinyl pyrrolidone, polyvinyl butyral, polyurethane, a silicone resin having the following structure

[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 thereof;

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

[0046] (ii) drying and / or curing the aqueous or solvent-based binder composition to allow the binder to coalesce and form a continuous elastic binder film at least on the thermal porous substrate; and then

[0047] (iii) applying a one-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 surface of the continuous elastic adhesive film and curing it.

[0048] As used herein, the concept “comprising” is used in its broadest sense to mean and encompass the concepts “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; nitrogen atoms; groups containing nitrogen atoms such as amino functional groups, amido functional groups, and cyano functional groups; sulfur atoms; and groups containing sulfur atoms such as mercapto groups.

[0050] A one-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 meets most of the requirements as a replacement for neutral oxime sealants. However, this blistering effect at high temperatures is an inherent problem of alkoxy-cured sealants when applied directly onto hot porous substrate surfaces, which is not encountered in the case of oxime sealants because MEKO has the above-mentioned high boiling point of 153° C. and a vapor pressure of 3 mmHg at 20° C. (both from standard texts), which is different from the alcohol by-product generated during the curing process of the one-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.

[0051] The method described herein comprises 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 one-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 continuous elastic adhesive film on the substrate, and then exposing the combination of the substrate and sealant composition to atmospheric moisture to obtain a silicone sealant bonded to a hot porous substrate, etc.

[0052] The method was found to produce a cured product of a one-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 that bonds to a hot porous substrate at a temperature of at least 40°C, which cured product contains a reduced number of bubbles when applied directly onto a hot substrate surface compared to an equivalent cured product. In addition to the reduced number of bubbles formed, the bubbles that are formed are smaller in diameter. Thus, we surprisingly found that providing a continuous elastic adhesive film on a hot porous substrate prior to applying a one-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 effectively prevents capillary action in the substrate and, therefore, prevents the generation of alcohol at the substrate / one-part room temperature vulcanizable (RTV) silicone composition interface.

[0053] It is important that 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 brittle. The thickness of the film is or preferably is a minimum of 30 μm. This can be determined, for example, in a laboratory setting by checking the thickness of the substrate before applying the aqueous or solvent-based adhesive composition, and then subsequently checking the thickness of the substrate with the applied continuous elastic coating film and determining the difference. Typically, the thickness of the continuous elastic adhesive film is in the range of 30 μm to 300 μm, alternatively 50 μm to 200 μm.

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

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

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

[0057] Where 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 exemplary (meth) acrylic resins, the binder used can have any suitable weight average molecular weight, such as 10,000 g / mol to 5,000,000 g / mol, such as 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 indicated, the phrase "molecular weight" refers to the weight average molecular weight measured by gel permeation chromatography (GPC) relative to polystyrene (PS) standards.

[0059] (Meth)acrylic acid based resins are formed by the polymerization of esters of acrylic acid or methacrylic acid with various special (meth)acrylate monomers. As used herein, the term (meth)acrylate is intended to refer to both acrylates and methacrylates.

[0060] When the binder in the 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 include particles and / or microparticles of (meth) acrylic polymer resins or be composed thereof. Such (meth) acrylic resin particles will have a particle size diameter in the range of 75nm to 450nm, alternatively 100nm to 375nm, alternatively 115nm to 375nm, or alternatively 150nm to 300nm. As used herein, unless otherwise indicated, the term "average particle size" for (meth) acrylic resins refers to the particle size measured by light scattering (LS) using the BI-90 particle size analyzer of Brookhaven Instruments Corp. (Holtsville, NY, New York).

[0061] The (meth)acrylic resin may 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, alternatively from 100,000 g / mol to 750,000 g / mol. As used herein, unless otherwise indicated, the phrase "molecular weight" (for (meth)acrylic resins) refers to the weight average molecular weight measured by gel permeation chromatography (GPC) relative to polystyrene (PS) standards.

[0062] The (meth)acrylic resin may have any suitable glass transition temperature (Tg), for example, it may have a Tg in the range of -50°C to 100°C. The (meth)acrylic resin may have a pH in the range of 7 to 10. As used herein, unless otherwise indicated, the term "Tg" or "glass transition temperature" of a polymer with respect to a (meth)acrylic emulsion and its components refers to the Tg of the polymer calculated using the Fox equation (TGFox, Bull. Am. Physics Soc., Vol. 1, No. 3, p. 123 (1956)).

[0063] Representative, non-limiting examples of commercially produced aqueous dispersions of (meth)acrylic polymers useful in the binders of the present disclosure include those sold under the following trade names: 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-285andPRIMAL 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 Rohm from Darmstadt, Germany ( PLEXIGLAS GmbHof Darmstadt Germany) TM 6N, PLEXIGLAS TM 7N and PLEXIGLAS TM 8N.

[0064] For the avoidance of doubt, silicone resins according to the present disclosure may be described using shorthand (abbreviated) nomenclature using the following general formula:

[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 has a weight average molecular weight of about 1,000 to about 100,000 based on standard polystyrene by gel permeation chromatography.

[0067] Each R 1 -R 4 , R 5 ' and R 6 ' is independently selected from a monovalent hydrocarbon group, a methanol group, an alkoxy group (preferably a methoxy or ethoxy) or an amino group. 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 can be exemplified by, but not limited to, vinyl, allyl, and hexenyl. The silicone resin can be a DT resin, MT resin, MDT resin, DTQ resin, MTQ resin, MDTQ resin, DQ resin, DTQ resin, MTQ resin, or MDQ resin, wherein the main D units (R 4 R 5 SiO 2 / 2 ) and T unit (R 6 SiO 3 / 2 DT resins of 50% to 100% are particularly preferred. MQ resins (where a+d=1) are not used because they are too powdery and do not provide a continuous elastic film.

[0069] Solutions of aqueous or solvent-based binder compositions may consist solely of binder and solvent, provided the binder / solvent combination is viscous enough to be applied in a sufficiently thick layer and cured / dried.

[0070] When the aqueous or solvent-based binder composition is aqueous, the solvent used is water or substantially, ie at least 95%, water and, for example, small amounts of, for example, alcohol.

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

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

[0073] Straight or branched alkanes having 6 to 16 carbons, such as hexane, heptane, and octane; isoalkanes having 6 to 16 carbons, such as isodecane, isododecane, and isohexadecane; aromatic hydrocarbons, 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, methyl ethyl ketone; amines; esters, such as tert-butyl acetate, methyl acetate, ethyl acetate, n-butyl acetate, methyl formate, isodecyl neopentanoate, isohexyl neopentanoate, ethyl 3-ethoxypropionate, tridecyl neopentanoate, octyldodecyl neopentanoate, diisobutyl adipate, diisopropyl adipate, and octyl palmitate; ethers, such as octyl ether; glycols, such as propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, Alcohols; glycol ethers such as glycol n-butyl ether, propylene glycol n-butyl ether, propylene glycol dicaprylate / dicaprate, 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; white spirit; solvent oil; N-methylpyrrolidone; etc., and derivatives, modifications and combinations thereof.

[0074] The binder can be applied to the hot substrate surface as an aqueous composition comprising water and at least 25% by weight of the binder in the composition, alternatively from 25% to 75% by weight of the binder in the composition, alternatively from 27.5% to 75% by weight of the binder in the composition.

[0075] Alternatively, the binder may be applied in a solvent-based composition comprising a non-aqueous solvent and at least 25% by weight of the binder in the composition, alternatively from 25% to 75% by weight of the binder in the composition, alternatively from 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 binder. 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, mercaptosilanes, etc.) and catalysts, such as titanates, zirconates and / or aluminum organometallic compounds, and any combination thereof.

[0077] In the case of silane, one or more silanes having at least two or three hydrolyzable groups per molecule can be provided. Any suitable hydrolyzable group can be used, such as an alkoxy group, an acetoxy group and an oxime group, but preferably an alkoxy group. The alkoxy group can be the same or different, and generally has 1 to 10 carbons, alternatively 1 to 6 carbons, alternatively a methoxy or ethoxy group. When the silane has two or three hydrolyzable groups, such as two or three alkoxy groups, each other group is suitably an organic group bonded to silicon that is not hydrolyzable, which is generally a hydrocarbon group that can be substituted by halogens such as fluorine and chlorine. Examples of such other groups include alkyl groups (such as methyl, ethyl, propyl and butyl); cycloalkyl groups (such as cyclopentyl and cyclohexyl); alkenyl groups (such as vinyl and allyl); aryl groups (such as phenyl and tolyl); aralkyl groups (such as 2-phenylethyl) and groups obtained by replacing all or part of the hydrogen in the aforementioned organic groups with halogens. Preferably, however, each other silicon-bonded organic group is an alkyl group having 1 to 6 carbons (such as a methyl or ethyl group) or an alkenyl group having 2 to 6 carbons (such as a vinyl group).

[0078] Specific examples of silanes that can be incorporated into the aqueous or solvent-based adhesive composition as an additive include, but are not limited to, alkyltrialkoxysilanes such as methyltrimethoxysilane (MTM), ethyltrimethoxysilane and methyltriethoxysilane; alkenyltrialkoxysilanes such as vinyltrimethoxysilane and vinyltriethoxysilane, isobutyltrimethoxysilane (iBTM). Other suitable silanes include phenyltrimethoxysilane, alkoxytrioxime silane, alkenyltrioxime silane, 3,3,3-trifluoropropyltrimethoxysilane, methyltri(methylethylketoxime)silane, vinyl-tri-methylethylketoxime)silane, methyltri(methylethylketoxime)silane, methyltri(isopropenyloxy)silane, vinyltri(isopropenyloxy)silane, (ethylenediaminepropyl)trimethoxysilane, vinyltrimethoxysilane, tetraalkyl orthosilicates having the general formula SiOR4, tetraethoxysilane, mercapto-functionalized-silanes, glycidoxypropyltrimethoxysilane, and any combination thereof.

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

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

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

[0082] A small amount of commercial primers contain at least 25% by weight of a binder in the primer composition. Such primers are designed to have film-forming and adhesion-promoting effects on room temperature vulcanizable (RTV) silicone compositions when applied to substrates at room temperature (i.e., ceramic 20°C to 25°C). However, these are generally not required to adhere cured silicone materials to porous substrates (such as stone, marble, brick, concrete, cement and other cementitious substrates) at room temperature. In addition, there is no teaching that the primer needs 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 there is no prior art indicating that applying such primer compositions to substrates at a temperature of at least 40°C will prevent or substantially prevent the foaming problem in a one-part room temperature vulcanizable (RTV) silicone composition containing an organopolysiloxane polymer having at least two alkoxy groups per molecule and a tin (IV)-based catalyst occurring at those temperatures. Therefore, the method described herein is a surprising development that appears to solve a major problem in hot countries. Without being bound by present theory, it is believed that applying an aqueous or solvent-based adhesive composition results in the formation of an elastic adhesive film that blocks the pores on the substrate surface and thus prevents a bubbling effect when a one-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 the elastic adhesive film.

[0083] In other embodiments, it is determined that if desired, a predetermined amount of a binder selected from (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinyl pyrrolidone, polyvinyl butyral, polyurethane, or a silicone resin having the following structure can be introduced into the primer composition to form an aqueous or solvent-based binder composition comprising at least 25 wt. % of a binder in the primer composition:

[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 mixtures thereof. The adhesion performance of the aqueous or solventborne binder composition when it comprises a primer or a modified primer containing an additional binder is considered superfluous for this application, provided that the modified primer composition is capable of forming a suitable continuous elastic binder film when applied to a hot porous substrate at 40°C.

[0086] Any suitable primer can be used for this application, and condition is that they contain the binding agent (at least 25 weight %) of necessary amount in their composition, or they can be modified to contain these binding agents.This type of primer can be water-based or solvent-based.In the case of solvent-based primer, solvent can be any one of those listed above for the binding agent composition.They can contain a variety of other ingredients, for example, one or more silanes and catalysts with at least three hydrolyzable groups per molecule, for example titanates, zirconates and / or aluminum organometallic compounds as described above.They can additionally include one or more organotin compounds, such as but not limited to alkyl tin ester compounds, such as dibutyl tin dioctoate, dibutyl tin dimaleate, 2-ethylhexanoic acid butyl tin, dimethyl tin dineodecanyl ester or dibutyl tin dilaurate, dibutyl tin acetate and 2-ethylhexanoic acid dibutyl tin, and any combination thereof.

[0087] Any suitable silicone sealant primer suitable for priming the porous substrates described herein (i.e., architectural and / or building 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 composition herein. For example, commercial primers that can be used include DOWSIL TM Building Primer B and DOWSIL TM Architectural Primer P, and commercial primers that can be used as waterborne or solventborne binder compositions when modified by the addition of a binder 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 a 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 binder composition comprising at least 25% by weight of the binder selected from (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinyl pyrrolidone, polyvinyl butyral, polyurethane or silicone resins or a mixture of two or more thereof as described above is applied to the surface of the thermoporous substrate at a temperature of at least 40° C. The thermoporous 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 may be a stone facade that can be heated to a temperature well above 40° C. in direct sunlight.

[0089] Any suitable silicone sealant primer suitable for priming the porous substrates described herein (i.e., architectural and / or building materials used to form the exterior of buildings, such as concrete, marble, brick, and stone) can be used in the present disclosure. The aqueous or solvent-based binder composition is contacted with the hot porous surface by conventional means such as extrusion, coating, injection, knife coating, 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 the selected solvent together and introducing any additional ingredients 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 the surface of the thermal porous substrate at a temperature of at least 40° C. contains at least 25% by weight of the 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 ingredients in the solvent.

[0091] In step (ii) of the method, the aqueous or solvent-based adhesive composition is dried and / or cured so that the adhesive can coalesce and form a continuous elastic adhesive film on the thermal porous substrate. The resulting continuous elastic adhesive film comprises all non-volatile components of the aqueous or solvent-based adhesive composition, and therefore if a modified primer is used, all non-volatile components of the modified silicone sealant primer are included. In fact, it is possible that one or more of the components of the aqueous or solvent-based adhesive composition applied as herein can react with the adhesive during the formation of the continuous elastic adhesive film. Given the temperature of the thermal porous substrate and caused by sunlight / air near the substrate, the drying / curing of the aqueous or solvent-based adhesive composition does not require methods such as heating. Compared with drying / curing at a temperature of, for example, 20°C to 25°C, the temperature of the climate rise will actually accelerate the drying / curing period.

[0092] In step (iii), a one-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 from step (ii) and cured thereon. It is applied on top of the continuous elastic adhesive film and then allowed to cure at the ambient temperature at the time of application. The method herein prevents or minimizes undesirable bubbling problems when a one-part room temperature vulcanizable (RTV, i.e., typically 20°C to 25°C) silicone composition is applied to a hot porous substrate at a temperature above 40°C, because the continuous elastic adhesive film produced by applying the aqueous or solvent-based adhesive composition to the surface of the hot porous substrate will effectively isolate the one-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 from the surface of the substrate and prevent direct contact between the substrate surface and the one-part room temperature vulcanizable (RTV) silicone composition during the curing process when bubbling occurs.

[0093] Most one-part room temperature vulcanizable (RTV) silicone compositions having at least two alkoxy groups per molecule and containing a tin(IV) based catalyst typically contain a minimum of four ingredients:

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

[0095] 2. one or more suitable cross-linking agents;

[0096] 3. Fillers; and

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

[0098] One-part room temperature vulcanizable (RTV) silicone compositions having at least two alkoxy groups per molecule and containing a tin (IV) based catalyst also typically include a variety of additives that are incorporated into the compositions to meet the necessary properties required by the applicant / building industry in which they are used. Such additives typically include one or more of adhesion promoters, diluents (e.g., plasticizers and / or extenders), chain extenders, flame retardants, solvent resistance additives, biocides, etc., which are also typically incorporated into these compositions as needed and when required.

[0099] One advantage of the present method is that any suitable one-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 hot porous substrate at a temperature of at least 40° C. by preparing a continuous elastic adhesive film on the hot porous substrate prior to applying the one-part room temperature vulcanizable (RTV) silicone composition having at least two alkoxy groups per molecule and containing a tin(IV)-based catalyst. An example of a typical one-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, but it should be understood that such a composition is provided merely as an example of the type of composition that may be selected for use and is in no way intended to limit the scope of one-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 a hot porous substrate in view of the new method. A one-part room temperature vulcanizable (RTV) silicone composition having at least two alkoxy groups per molecule and containing a tin (IV) based catalyst may 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] An organopolysiloxane polymer having at least two hydroxyl groups or hydrolyzable groups per molecule of the formula:

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

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

[0105] (II) a suitable cross-linking agent having three or more hydrolyzable groups per molecule;

[0106] (III) a filler selected from precipitated silica, fumed silica or precipitated calcium carbonate or a mixture of two or more thereof;

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

[0108] Organopolysiloxane polymer (I) having at least two alkoxy groups per molecule

[0109] The organopolysiloxane polymer (I) having at least two alkoxy groups per molecule has 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 can 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, pentyloxy, hexyloxy and 2-ethylhexyloxy; dialkoxy groups, such as methoxymethoxy or ethoxymethoxy, and alkoxyaryloxy such as ethoxyphenoxy groups; alternatively, each X is an alkoxy group with one to six carbons, alternatively with 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 with 1 to 6 carbons, an alkenyl group with 2 to 6 carbons (such as vinyl, allyl and hexenyl groups) or an aryl group with 6 to 12 carbons; alternatively each R is an alkyl group with 1 to 6 carbons, or an aryl group with 6 to 12 carbons; alternatively each R is an alkyl group with 1 to 6 carbons, alternatively each R is an ethyl group or a methyl group. In one embodiment, R may include a substituted aliphatic organic group, such as a 3,3,3-trifluoropropyl group, an aminoalkyl group, a polyaminoalkyl group and / or an alkylene oxide group.

[0113] Each R 1is an X group, or an R group, provided that cumulatively at least two X groups and / or R groups per molecule 1 The group is an alkoxy group, alternatively each R 1 is an R group. It is possible that some R 1 The groups may be siloxane branches branching from the polymer backbone and these branches may 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, alternatively an alkylene group having 2 to 5 carbons. 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, substantially y=2, for example at least 90%, alternatively 95%, of R 1 y SiO (4-y) / 2 The group is characterized in that y = 2. The subscript z is an integer such that the organopolysiloxane polymer has a viscosity of 30,000 to 150,000 mPa.s, alternatively 40,000 to 140,000 mPa.s at 25°C, so 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 cone-plate geometry, using spindle 52 at 5 rpm for 2 min.

[0116] Component (I) is present in the one-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, 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 the organopolysiloxane polymer (I) is meant to include 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 an organosilicon. Synthetic polymers always consist of a mixture of macromolecular species with different degrees of polymerization and therefore different molecular weights. There are different types of average polymer molecular weights, which can be measured in different experiments. The two most important average polymer molecular weights are the number average molecular weight (Mn) and the 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 about 10% to 15%.

[0119] The 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 measured from GPC, and Mu is the molecular weight of the monomer unit. PI = Mw / Mn. DP is associated with the viscosity of the polymer via Mw, and the higher the DP, the higher the viscosity. In the present disclosure, the number average molecular weight and weight average molecular weight values ​​of component (I) herein can be measured, 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. Certified grade toluene flowing at 1.0 mL / min can then be used as an eluent for analysis. Data collection and analysis can be performed using Waters Empower GPC software.

[0120] Polymer (I) may be prepared by any suitable route, for example by preparing an alkoxy terminated polydiorganosiloxane from a silanol terminated polydiorganosiloxane starting material comprising:-

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

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

[0123] Alkanesulfonic acids having 1 to 10 carbon atoms;

[0124] Acidic fumed silica and / or

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

[0126] Suitable crosslinking agents (II) having 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] The silicon-containing compound having at least three alkoxy groups per molecule of component (II) may be, for example:

[0129] One or more silanes having at least 3 hydrolyzable groups per molecular group;

[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 have at least three hydroxyl and / or hydrolyzable groups per molecule.

[0132] For the purposes of this disclosure, a bipodal 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 or a siloxane polymer chain or copolymer chain. Typically, each silyl group on the bipodal silane can be a terminal group.

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

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

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

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

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

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

[0139] Suitable as R 8 The unsubstituted monovalent hydrocarbon group may include an alkyl group (e.g., methyl, ethyl, propyl, and other alkyl groups), an alkenyl group (such as vinyl), and the cycloalkyl group may include a cyclopentane group and a cyclohexane group. For example, 8 The substituted groups may include a 3-hydroxypropyl group, a 3-(2-hydroxyethoxy)alkyl group, a halopropyl group, a 3-mercaptopropyl group, a trifluoroalkyl group such as a 3,3,3-trifluoropropyl group, a 2,3-epoxypropyl group, a 3,4-epoxybutyl group, a 4,5-epoxypentyl group, a 2-glycidyloxyethyl group, a 3-glycidyloxypropyl group, a 4-glycidyloxybutyl group, a 2-(3,4-epoxycyclohexyl)ethyl group, a 3-(3,4-epoxycyclohexyl)alkyl group, an aminopropyl group, an N-methylaminopropyl group, an N-butylaminopropyl group, an N,N-dibutylaminopropyl group, a 3-(2-aminoethoxy)propyl group, a methacryloyloxyalkyl group, an acryloxyalkyl group, a carboxyalkyl group such as a 3-carboxypropyl group, and a 10-carboxydecyl group.

[0140] Specific examples of suitable silane crosslinkers (II) having at least 3 hydroxyl groups and / or hydrolyzable groups per molecule include, but are not limited to, vinyltrimethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane, ethyltrimethoxysilane, propyltriethoxysilane, isobutyltriethoxysilane, isobutyltrimethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, methyltri(isopropenyloxy)silane or vinyltri(isopropenyloxy)silane, 3-hydroxypropyl ... triethoxysilane, 3-hydroxypropyl trimethoxysilane, 3-(2-hydroxyethoxy)ethyl triethoxysilane, 3-(2-hydroxyethoxy)ethyl trimethoxysilane, chloropropyl triethoxysilane, 3-mercaptopropyl triethoxysilane, 3,3,3-trifluoropropyl triethoxysilane, 2,3-epoxypropyl triethoxysilane, 2,3-epoxypropyl trimethoxysilane, 3,4-epoxybutyl triethoxysilane, 3,4-epoxybutyl trimethoxysilane, 4,5-epoxypentyl triethoxysilane , 4,5-epoxypentyl trimethoxysilane, 2-glycidyloxyethyl triethoxysilane, 2-glycidyloxyethyl trimethoxysilane, 3-glycidyloxypropyl triethoxysilane, 3-glycidyloxypropyl trimethoxysilane, 4-glycidyloxybutyl triethoxysilane, 4-glycidyloxybutyl trimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl triethoxysilane, 3-(3,4-epoxycyclohexyl)ethyl triethoxysilane, aminopropyl triethoxysilane triethoxysilane, 3-(2-aminoethoxy)propyltriethoxysilane, methacryloxypropyltriethoxysilane, tris(3-triethoxysilylpropyl)isocyanurate, acryloxypropyltriethoxysilane, 3-carboxypropyltriethoxysilane and 10-carboxydecyltriethoxysilane.

[0141] In other embodiments, component (II) can be a bipedal silane, i.e. a silyl functional molecule having at least 2 silyl groups, each silyl group having at least 1 and at most 3 hydrolyzable groups, alternatively each silyl group having at least 2 hydrolyzable groups, wherein the silyl groups are separated by a polymer backbone. The polymer backbone can be an organic polymer backbone, i.e. component (II) can include an organic-based polymer having silyl terminal groups, for example, silyl polyethers, silyl acrylates, and silyl-terminated polyisobutylenes. In the case of silyl polyethers, the polymer chain is based on polyoxyalkylene units. Such polyoxyalkylene units preferably include repeating oxyalkylene units (-C n H 2n-O-)-based linear oxyalkylene polymers, the polymers having an average formula (-C n H 2n -O-) y Represents, wherein n is an integer from 2 to 4 (inclusive), and y is an integer of at least four. Likewise, 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 polyoxyalkylene polymer block present. As described above, the viscosity can be measured using any suitable apparatus, such as a Modular Compact Rheometer (MCR) 302 from Anton Paar GmbH of Graz, Austria, using the most appropriate settings and plates for the viscosity involved. In addition, the oxyalkylene units do not have to be all the same in the polyoxyalkylene monomers, but can be different between units. The polyoxyalkylene blocks or polymers may, for example, be composed of oxyethylene units (-C2H4-O-); oxypropylene units (-C3H6-O-); or oxybutylene units (-C4H8-O-); or mixtures thereof.

[0142] In the case of such crosslinkers based on organic substances, the molecular structure may be linear, branched, cyclic or macromolecular, ie an organic polymer chain with alkoxy-functionalized end groups.

[0143] In one embodiment, the bipodal silane may be a polymer containing two silyl groups, each silyl group containing at least one hydrolyzable group, such as described by the following formula:

[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 is an alkyl group containing 1 to 8 carbon atoms,

[0146] Q is a chemical group containing a heteroatom having a lone pair of electrons, such as an amine, an N-alkylamine, or a 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] Specific examples of suitable bipodal silanes include 1,6-bis(trimethoxysilyl)hexane (alternatively known as hexamethoxydisilylhexane), bis(trialkoxysilylalkyl)amine, bis(dialkoxyalkylsilylalkyl)amine, bis(trialkoxysilylalkyl)N-alkylamine, bis(dialkoxyalkylsilylalkyl)N-alkylamine, bis(trialkoxysilylalkyl)urea, bis(dialkoxyalkylsilylalkyl)urea, bis(3-trimethoxysilylpropyl)amine, bis(3-triethoxysilylpropyl)amine, 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,

[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 polydialkylsiloxane, di- or trialkoxysilyl-terminated polyaralkylsiloxane, di- or trialkoxysilyl-terminated polypropylene oxide, polyurethane, polyacrylate; polyisobutylene; di- or triacetoxysilyl-terminated polydialkyl; polyaralkylsiloxane; di- or trioxime-terminated polydialkyl; polyaralkylsiloxane; di- or triacetoneoxy-terminated polydialkyl or polyaralkyl. Component (II) used may also contain any combination of two or more of the above.

[0158] Other suitable silicon-containing compounds having at least three hydroxyl 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 may be the same or different and are divalent alkylene groups having 2 to 10 carbons, alternatively 2 to 6 carbons, alternatively 2 to 5 carbons, and each R 6 are the same or different and are alkyl groups having 1 to 10 carbons, alternatively 1 to 6 carbons, alternatively 1 to 4 carbons, alternatively methyl groups or ethyl groups. An example is tris-(trimethoxysilylpropyl)isocyanurate as described below, wherein each R 5 is a propylene group and each R 6 It is a methyl group.

[0161]

[0162] One or more cross-linking agents (II) having at least 3 hydroxyl 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, alternatively in an amount of 1% to 3.5% by weight of the composition.

[0163] One or more reinforcing fillers (III)

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

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

[0166] The reinforcing filler (III) can be treated with hydrophobic treatment, for example, with one or more aliphatic acids (e.g., fatty acids such as stearic acid, or fatty acid esters such as stearic acid esters), or with organosilanes, organosiloxanes or organosilazane hexaalkyldisilazane or short-chain siloxane diols, so that the filler is hydrophobic and therefore easier to handle and obtain a uniform mixture with other adhesive 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 polydiorganosiloxanes containing an average of 2 to 20 repeating units of diorganosiloxanes per molecule, hydroxydimethyl-terminated phenylmethylsiloxanes, hexaorganodisiloxanes such as hexamethyldisiloxane, divinyltetrasiloxane, dimethyl ... Methyldisiloxanes; hexaorganodisilazanes such as hexamethyldisilazane (HMDZ), divinyltetramethyldisilazane and tetramethylbis(trifluoropropyl)disilazane; hydroxydimethyl terminated polydimethylmethylvinylsiloxane, octamethylcyclotetrasiloxane and silanes including but not limited to methyltrimethoxysilane, dimethyldimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, trimethylchlorosilane, dimethyldichlorosilane, trichloromethylsilane.

[0167] The surface treatment of the filler makes it easy to be wetted by component (I). These surface modified fillers are preferably in a finely divided form and do not agglomerate and can be uniformly incorporated into the organosilicon polymer (I). This leads to 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 a silica treatment agent as a processing aid.

[0168] According to the selected filler, reinforcing filler (III) can be present in an amount of 2.5 % by weight to 60 % by weight (wt.%) of the composition. In the case where the selected filler is precipitated silica and / or pyrogenic silica or a combination thereof, inorganic filler (III) is present in a range of about 5.0 % by weight to 35 % by weight of the composition, alternatively 5 % by weight to 30 % by weight of the composition, alternatively 5 % by weight to 25 % by weight of the composition. However, when reinforcing filler (III) is precipitated calcium carbonate, the composition will tend to comprise a composition of a larger % by weight, such as a composition of 25 % by weight to 60 % by weight, alternatively 30 % by weight to 60 % by weight, alternatively 35 % by weight to 55 % by weight. When component (III) is a mixture of silicon dioxide and precipitated calcium carbonate, % by weight will generally be between them.

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

[0170] Component (IV) comprises a condensation catalyst which increases the speed at which the composition cures.

[0171] The component (d) tin (iv) catalyst may be any suitable tin (iv) based condensation curing catalyst. Examples of suitable tin (iv) based catalysts include tin trifluoromethanesulfonate, dialkyl tin compounds selected from dimethyltin di-2-ethylhexanoate, dimethyltin dilaurate, di-n-butyltin diacetate (DBTDA), di-n-butyltin di-2-ethylhexanoate, dimethyltin dineodecanoate (DMTDN), dioctyltin dineodecanoate (DOTDN), di-n-butyltin dioctoate, di-n-butyltin di-2,2-dimethyloctoate, di-n-butyltin octoate, dilaurate, di-n-butyltin diacetate (DBTDA), di-n-butyltin di-2-ethylhexanoate, dimethyltin dineodecanoate (DMTDN), dioctyltin dineodecanoate (DOTDN), di-n-butyltin dioctoate, di-n-butyltin dioctoate, di-n-butyltin dilaurate, di-n-butyltin dioctoate ... 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, tri-methylphenyltin suberate, tin butyrate, butyltin tri-2-ethylhexanoate, tin naphthenate, isobutyltin triceroate, tin octanoate, triethyltin tartrate, and di-n-octyltin oxide. The amount of the tin (iv)-based condensation catalyst is from 0.001 weight percent (wt.%) to 0.1 weight percent (including the end value) of the composition.

[0172] Optional additives

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

[0174] Non-reinforcing fillers

[0175] Non-reinforcing fillers that may be used in addition to component (III) herein include bauxite, calcium sulfate (anhydrite), gypsum, nepheline, syenite, quartz, calcium sulfate, magnesium carbonate, ground calcium carbonate, clays such as kaolin, alumina trihydrate, magnesium hydroxide (brucite), graphite, copper carbonates such as malachite, nickel carbonates such as trevally, barium carbonates such as witherite, and / or strontium carbonates such as strontianite.

[0176] Alumina, silicates selected from the group consisting of: olivines; garnets; aluminosilicates; cyclosilicates; inosilicates; and sheet silicates. Olivines include silicate minerals such as, but not limited to, forsterite and Mg2SiO4. Garnets include ground silicate minerals such as, but not limited to, pyrope; Mg3Al2Si3O 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] Cyclosilicates include silicate minerals such as, but not limited to, cordierite and Al3(Mg,Fe)2[Si4AlO 18 ]. Inosilicates include ground silicate minerals such as, but not limited to, wollastonite and Ca[SiO3].

[0178] Sheet 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, such as asbestos; kaolinite; Al4[Si4O 10 ](OH)8; and vermiculite.

[0179] Such additional fillers can also be hydrophobically treated in the same manner as above-mentioned component (III). When present, non-reinforcing fillers tend to be used to replace some components (III), so when component (III) reinforcing filler is precipitated calcium carbonate and non-reinforcing filler is also present in composition, the total amount of precipitated calcium carbonate and non-reinforcing filler will still not exceed the upper limit 60 wt % of composition. In one embodiment of composition, when component (III) is precipitated calcium carbonate, said composition also comprises heavy calcium carbonate. When present, non-reinforcing filler can exist in an amount greater than zero wt % to 25 wt % of composition.

[0180] pigment

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

[0182] Typically, the pigment and / or colorant, when particulate, has 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, the pigment and / or colorant is present in the range of 2 wt%, alternatively 3 wt%, alternatively 5 wt% to 20 wt% of the composition.

[0183] Rheology Modifiers

[0184] Rheology modifiers that can be incorporated into a one-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 based on polyether or polyester polyols 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 diols. For some systems, these rheology modifiers, especially copolymers of ethylene oxide and propylene oxide and silicone polyether copolymers, can enhance adhesion to substrates, especially plastic substrates.

[0185] Tackifier

[0186] The one-part room temperature vulcanizable (RTV) silicone composition as described above may also include an aminosilane adhesion promoter having two or three hydroxyl or alkoxy groups per molecule. The aminosilane adhesion promoter 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 is an alkyl group containing 1 to 10 carbon atoms; each R 11 May be the same or different and be H or R 10 , Z 2 is a straight or branched alkylene group having 2 to 10 carbon atoms, m′ is 2 to 10, and k is zero or 1.

[0189] R 10 is an alkyl group containing 1 to 10 carbon atoms, or R 10 is an alkyl group containing 1 to 6 carbon atoms, alternatively R 10 is a methyl group or an ethyl group. 11can be the same or different, and each R 11 may be the same or different and be H or R or R 10 , alternatively, each R 11 For R 10 In an alternative embodiment, all R 11 The groups are the same. 11 When the groups are the same, it is preferred that they are methyl or ethyl groups. 2 is a straight chain or branched alkylene group having 2 to 10 carbon atoms, alternatively 2 to 6 carbon atoms, for example 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 adhesion promoters that may be used include N-(3-(trimethoxysilyl)propyl)butylamine, bis(trimethoxysilylpropyl)amine, bis[3-(triethoxysilyl)propyl]amine, bis[3-(triethoxysilyl)propyl]amine, aminopropyltriethoxysilane, and aminopropyltrimethoxysilane.

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

[0192] UV and / or light stabilizers

[0193] For purposes of example, the UV and / or light stabilizer may include benzotriazole, ultraviolet light absorber and / or hindered amine light stabilizer (HALS), such as HALS from Ciba Specialty Chemicals Inc. Product series.

[0194] Biocides

[0195] If desired, a biocide may additionally be utilized in the composition. The term "biocide" is intended to include bactericides, fungicides, algaecides, and the like.

[0196] The one-part room temperature vulcanizable (RTV) silicone composition as described above can be prepared by mixing all the ingredients together. Preferably, once mixed, the composition is sealed in one or more moisture-proof containers and stored unless used immediately. In one embodiment, filler (III) and / or pigment are first mixed into polymer (I) when present, optionally, if desired, in combination with a hydrophobic treatment agent, so that the filler and optional pigment can be hydrophobized in situ during mixing into the polymer.

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

[0198] For example, in one approach, a method for preparing a one-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, prepare a suitable capping catalyst (such as 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD)) by dissolving the TBD capping catalyst in methyltrimethoxysilane.

[0201] 1 wt % solution in methyltrimethoxysilane followed by the addition of vinyltrimethoxysilane to provide a blocked catalyst solution;

[0202] 2) mixing the polymer and any plasticizer (if present);

[0203] 3) then introducing the blocked catalyst mixture into the mixture obtained from step 2 above, and then stirring the combination at room temperature for a predetermined period of time (e.g., 10 minutes to 45 minutes);

[0204] A one-part organopolysiloxane elastomer composition utilizing the product of the above alkoxy-terminated reaction was then prepared using the following additional steps:

[0205] 4) Premix the condensation cure catalyst and any adhesion promoter (when present) (e.g., N-[3-(trimethoxysilyl)propyl]ethylenediamine or 3-(trimethoxysilyl)-propylamine)

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

[0207] 5) Mixture 2 was introduced into the mixer and everything was mixed for a further 5 minutes;

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

[0209] 7) After the filler is fully mixed, hexamethyldisilazane is added; and

[0210] 8) The composition was then further mixed under vacuum for 10 minutes before packaging the final one-part organopolysiloxane elastomer composition.

[0211] Due to the presence of the above-mentioned alcohol (especially methanol) and the tin catalyst, the polymer is susceptible to the influence of the tin catalyst and the polymer backbone is reversed and / or the polymer will be easily degraded, resulting in a very poor shelf life. Hexamethyldisilazane (HMDZ) is used as a methanol scavenger to ensure a better shelf life. However, HMDZ is very reactive and easily hydrolyzes during storage to produce ammonia. In this case, the use of HMDZ expands the possibility of bubbles on hot porous surfaces at 40°C or higher temperatures. However, by using a binder composition containing at least 25% by weight of a binder as described herein (e.g., pmma) in the method described herein, foaming is significantly reduced.

[0212] In step (iii), the one-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 may be applied to the continuous elastic adhesive film by any suitable means, such as by extrusion, coating, injection, knife coating and rolling, which generally depends on its viscosity and flowability on the continuous elastic adhesive film. Regardless of the application mode, it is found that when applied on top of the adhesive intermediate layer, rather than directly applied to the substrate surface at a temperature of 40° C. or higher, no bubbles or relatively much fewer bubbles are formed in a standard one-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, rather than when the standard one-part room temperature vulcanizable (RTV) silicone composition is applied directly to a hot porous substrate surface at a temperature of at least 40° C., where a lot of bubbles form resulting in very poor adhesion. The reduction in the number and size of bubbles in cured silicone sealants is beneficial to the construction industry in hot countries where substrates often reach temperatures in excess of 40°C during the hottest part of the day due to heat from the sun etc., as significant bubble formation with standard sealants has proven to be a major problem in the construction industry as it results in surface bubbling between the curing / cured sealant and the substrate surface, resulting in poor adhesion therebetween, which is unacceptable.

[0213] Another advantage of the present method is that the continuous elastomeric adhesive film protects and insulates the one-part room temperature vulcanizable (RTV) silicone composition from the temperature of the substrate, which allows the user to have increased working time compared to applying the one-part room temperature vulcanizable (RTV) silicone composition directly to the hot porous substrate at 40° C. These compositions tend to cure very quickly at the relevant temperatures because after the one-part room temperature vulcanizable (RTV) silicone composition is applied to the hot porous substrate; it is exposed to atmospheric moisture, causing it to undergo accelerated curing.

[0214] Also provided is a sealed porous substrate as a product of the above method.The one-part room temperature vulcanizable (RTV) silicone composition used herein can be used as a sealant or adhesive, or as a weatherseal or specialty caulking or residential and industrial framing board adhesive and sealant. Example

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

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

[0217] DOWSIL TM 1200 OS Primer is a primer for silicone adhesives and sealants, which 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 ​​taken from the data sheet). It does not contain any polymethyl methacrylate.

[0218] DOWSIL TM Primer-C is a solvent-based silane primer suitable for a variety of applications. It has an 800ft 2 / Gallon(16.33m 2 / L) of non-porous substrate coverage, a specific gravity of 0.90, a color flash point of -4°C, and a VOC content of 1,855 g / L based on the maximum VOC of the California South Coast Air Quality Management District (all values ​​are taken from the data table). It contains about 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 in solvent for masonry surfaces. It is a clear liquid with a specific gravity of 0.95 (ASTM D 1298), a flash point of 8°C (closed cup), a sealer application time of 0.5 to 8 hours at 25°C, and a VOC content of 748 g / L based on the California South Coast Air Quality Management District maximum VOC (all values ​​taken from the data table). It contains about 20% by weight of polyacrylate in the composition.

[0220] DOWSIL TM Architectural Primer B is a film-forming primer for use on porous and metal substrates, it is a clear liquid, has a specific gravity of 0.97 (ASTM D 1298), a flash point of 26°C (closed cup), a sealer application time of 0.5 hours to 8 hours at 25°C, a VOC content of 577 g / L based on the maximum VOC of the California South Coast Air Quality Management District (all values ​​are taken from the data table). It contains about 40% by weight of a methacrylate polymer in the composition. Two silicone resin materials are also used:

[0221] DT silicone resin solution. The DT silicone resin solution used was a clear / turbid solution having about 70 wt% DT silicone resin (CTM 0208) in toluene and a viscosity of about 950 mPa.s at 25°C (CTM 0004). The 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] Contains 0.65 mole fraction of D units (where R 4 and R 5 is a methyl group), 0.09 mole fraction of T units (where R 6 is a methyl group) and 0.26 mole fraction of T units (where R 6 is phenyl).

[0224] In addition, a binder solution was prepared:

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

[0226] All commercial primers used are commercially available from Dow Silicones, Midland, Michigan, USA.

[0227] In a first series of examples and comparative examples, a granite substrate was first coated with a continuous layer of an elastomeric adhesive film-forming composition at a temperature of about 50°C before being top-coated with a one-part room temperature vulcanizable (RTV) silicone composition.

[0228] Two one-part room temperature vulcanizable (RTV) silicone compositions were prepared using the method described in WO2022041180, but no stabilization was required in view of the immediate preparation of the sealant composition. The ingredients used to prepare the sealant composition are listed in Table 1 below:

[0229] Table 1. Ingredients used to prepare sealant formulations 1 and 2

[0230]

[0231]

[0232] Polymer 1 shown in Table 1 is a dimethylsilanol terminated polydimethylsiloxane having a viscosity of about 50,000 mPa.s, which was terminated with alkoxy groups 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 cone-plate geometry, at 5 rpm using spindle 52 for 2 min.

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

[0234] Polymer 2 is a trimethyl terminated polydimethylsiloxane having a viscosity of about 100 mPa.s at 25°C, which can be obtained from DOWSIL TM 200 fluid was commercially available from Dow Silicones, Midland, Michigan, USA;

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

[0236] The fumed silica used is available from Wacker as HDK TM V15D was 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 preparing a 1 wt % solution of a TBD capping catalyst in methyltrimethoxysilane by dissolving the TBD capping catalyst in methyltrimethoxysilane, and then adding vinyltrimethoxysilane to provide a capping catalyst solution;

[0239] 2) The polymer and plasticizer were mixed together in a 10 liter Turello mixer at about 400 rpm;

[0240] 3) The blocked catalyst mixture was then introduced into the mixture obtained in step 2 above, and the combination was then stirred at 400 rpm for 15 minutes at room temperature;

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

[0242] 4) premixing the condensation cure catalyst and adhesion promoter N-[3-(trimethoxysilyl)propyl]ethylenediamine used in Formulation 1 and 3-(trimethoxysilyl)-propylamine used in Formulation 2 to form Mixture 2;

[0243] 5) Mixture 2 was introduced into the mixer and everything was mixed for a further 5 minutes;

[0244] 6) Then add the fillers. These are calcium carbonate and silica in formulation 1 and only silica in formulation 2. The fillers are gradually added to the tank;

[0245] 7) After the filler is fully mixed, hexamethyldisilazane is added; and

[0246] 8) The composition was then further mixed under vacuum for 10 minutes before packaging the final one-part organopolysiloxane elastomer composition.

[0247] To increase the level of blistering that might occur, the one-part room temperature vulcanizable (RTV) silicone composition was aged at 50°C for a period of two weeks prior to conducting this evaluation, as it has been determined that blistering effects are most pronounced if the applied sealant composition has been stored for a period of time prior to use.

[0248] The granite substrate was cleaned using isopropyl alcohol and then heated to about 50°C. Subsequently, the tested adhesive composition was applied by brush and then dried by evaporation of 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 that it was at a temperature of at least 50°C when the sealant composition was applied. The adhesive-coated granite substrate was removed from the oven, the sealant composition was applied on top of the adhesive coating, and then immediately returned to the oven to keep the sealant at about 50°C for the curing process. After curing, each sample was first visually evaluated to observe whether there was obvious surface bubbling on the sealant surface, and then the sealant layer was cut from one side to check whether there were bubbles at the interface between the sealant and the substrate. The results for Formulation 1 are provided in Tables 2a and 2b, and the results for Formulation 2 are provided in Tables 3a and 3b for Formulation 2.

[0249] Table 2a: Foaming behavior of Ref.1 and Comparative Examples C.1 to 3 using Silicone Sealant Formulation 1

[0250] Ref.1 C.1 C.2 C.3 Binder / film former / 1200OS Primer C Primer P Polyacrylate content in binder / 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 status 5 5 5 5

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

[0252] 1 = no bubbling observed;

[0253] 2 = very small bubbling, no effect on adhesion;

[0254] 3 = some bubbling, which may have a negative effect on adhesion;

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

[0256] 5 = Very significant bubbling was observed, with little adhesion (easily peeled off by hand).

[0257] The same criteria were used for all examples and comparative examples. In Reference 1, the sealant composition of Table 1 (Formulation 1) was applied directly onto the granite surface, and therefore, as expected, a high level of blistering 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 the case of Comparative Examples C.1, C.2 and C.3, each substrate was coated with a primer, which in C.1 was DOWSIL TM 1200 OS primer, which does not contain a binder, in C.2 it is DOWSIL TM Primer-C, which contains about 5 wt% polymethyl methacrylate, and in C.3 it is DOWSIL TMArchitectural primer P, which contains about 20% by weight of polymethyl methacrylate. In these cases, considering the lack or low level of binder content, the primer coating is very thin, with a thickness of about 5μm-20μm. The thickness of the standard primer (non-film-forming) coating applied to the substrate is usually no more than 12.5μm thick, which is much thinner than the continuous elastic adhesive film layer of at least 30μm but usually up to about 50μm described herein. Although the thickness of the coating was not measured, the thickness of the standard primer (non-film-forming) coating applied to the substrate is usually no more than 12.5μm thick, which is much thinner than the continuous elastic adhesive film layer of at least 20μm but usually up to about 30μm described herein. It was observed that the coating was discontinuous on the porous substrate 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 is found that although they can enhance the 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, it appears that the presence of a continuous adhesive film between the hot granite surface and the one-part room temperature vulcanizable (RTV) silicone composition (Formulation 1) in C.1 to 3 resulted in better adhesion between the hot granite and the resulting silicone sealant at about 50°C, however there was no or minimal difference with respect to blistering. This teaches that it is not the application of the primer itself to the substrate surface that prevents or minimizes blistering.

[0260] Table 2b: Blistering behavior of Ex. 1 to Ex. 3 using sealant formulation 1

[0261]

[0262]

[0263] In Table 2b, Res t It means elasticity.

[0264] In contrast, in Ex. 1, Ex. 2 and Ex. 3, the binder composition used to coat the granite surface comprises 30 wt.% PMMA Sol n 、DOWSIL TMArchitectural Primer B, which contains 40 wt% binder and 70 wt% DT resin binder, respectively. In each case, Ex. 1, Ex. 2 and Ex. 3 significantly reduced blistering in a one-part room temperature vulcanizable (RTV) silicone composition (Formulation 1) when applied over a binder composition layer. Thus, when comparing the results in Table 2a with the results in Table 2b, it can be seen that when Formulation 1 (calcium carbonate filled alkoxy sealant) was applied to a 50°C granite substrate, if no binder composition layer or a binder composition layer with a binder content of less than 30% was used (Table 2a), many bubbles appeared in the cured sealant, while when a binder composition containing a larger binder content was used, the blistering problem was significantly reduced (Ex. 1 to 3).

[0265] The sealant composition of formulation 2 in Table 1 above was then used to prepare a second series of examples, comparative reference example Ref. 2 and comparative examples C.4 to C.6. These were directly compared with Ex. 4 to 6, where 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: Blistering behavior of Ref.2 and Comparative Examples 4 to 6 containing sealant formulation 2

[0267] Ref.2 Comparative Example 4 Comparative Example 5 Comparative Example 6 Binder / film former / OS-1200 Primer C Primer P Polyacrylate content in binder / 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 status 5 5 5 5

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

[0269] Ex.4 Ex.5 Ex.6 Primer / film former 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 status 3 2 2

[0270] Similar results were obtained when comparing Ref.2 and Comparative Examples C.4 to 6 as shown in Table 3a with Ex.4, Ex.5 and Ex.6 using sealant formulation 2 as shown in Table 1 in each case. In each case, Ex.4, Ex.5 and Ex.6 significantly reduced the foaming in the one-part room temperature vulcanizable (RTV) silicone composition (Formulation 2) when applied to the binder composition layer. Thus, when comparing the results in Table 3a with the results in Table 3b, it can be seen that when Formulation 2 was applied to a granite substrate at about 50°C, if no binder composition layer or a binder composition layer with a binder content of less than 30% was used (Table 3a), many bubbles appeared in the cured sealant, while when a binder composition containing a larger binder content was used, the foaming problem was significantly reduced (Ex. 4 to 6).

Claims

1. A method of applying a one-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 thermal porous substrate at a temperature of at least 40° C., the method comprising the steps of: (i) applying an aqueous or solvent-based binder composition to a surface of a thermally porous substrate at a temperature of at least 40° C.; The aqueous or solvent-based binder composition comprises at least 25% by weight of the binder, wherein the binder is selected from (meth)acrylic resin, poly(meth)acrylic acid, polyvinyl acetate, polyvinyl pyrrolidone, polyvinyl butyral, polyurethane and a silicone resin having the following structure, or a mixture 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 binder composition to allow the binder to coalesce and form a continuous elastic binder film on the thermal porous substrate, and then (iii) applying a one-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 surface of the continuous elastic adhesive film and curing it.

2. The method according to claim 1, wherein the thermoporous 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 naphtha, tert-butyl acetate, methyl acetate, ethyl acetate, n-butyl acetate, methyl formate, ethyl formate and any combination thereof.

4. A method according to any preceding claim, wherein the solvent-borne binder composition comprises a non-aqueous solvent and 25% to 75% by weight of the binder in the composition.

5. A method according to any preceding claim, wherein the solvent-borne binder composition is a primer or modified primer containing from 25% to 75% by weight of the binder in the composition.

6. A method according to any preceding claim, wherein the binder is a (meth)acrylic resin or a DT silicone resin.

7. A thermally porous substrate sealed at a temperature of at least 40°C, said thermally porous substrate being the product of the process according to claims 1 to 6.

8. A thermally porous substrate sealed at a temperature of at least 40°C, the thermally porous substrate being coated with a cured layer of a one-part room temperature vulcanizable (RTV) silicone composition, the cured layer being obtained or obtainable by the following steps: (i) applying an aqueous or solvent-based binder composition to a surface of a thermally porous substrate at a temperature of at least 40° C.; The aqueous or solvent-based binder composition comprises at least 25% by weight of the binder, wherein the binder is selected from (meth)acrylic resin, poly(meth)acrylic acid, polyvinyl acetate, polyvinyl pyrrolidone, polyvinyl butyral, polyurethane and a silicone resin having the following structure, or a mixture 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 binder composition to allow the binder to coalesce and form a continuous elastic binder film on the thermal porous substrate, and then (iii) applying a one-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 surface of the continuous elastic adhesive film and curing it.

9. A thermally porous substrate sealed at a temperature of at least 40°C according to claim 7 or 8, having a continuous elastic adhesive film of 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 binder composition in a method for applying a one-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 aqueous or solvent-based binder composition comprising at least 25% by weight of the binder selected from the group consisting of (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinyl pyrrolidone, polyvinyl butyral, polyurethane and a silicone resin having the following structure, or a mixture of two or more thereof M (a) D (b) T (c) Q (d) When 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 comprises the following steps: applying an aqueous or solvent-based binder composition comprising at least 25% by weight of said binder to the surface of the thermally porous substrate at a temperature of at least 40°C; drying and / or curing the aqueous or solvent-based binder composition comprising at least 25% by weight of the binder to allow the binder to coalesce and form a continuous elastic binder film on the thermal porous substrate; And then A one-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.

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

13. Use of the method according to claims 1 to 6 for weatherproofing thermal porous substrates at temperatures of at least 40°C while preventing or minimizing the generation of bubbles in the one-part room temperature vulcanizable (RTV) silicone composition when cured at a temperature of at least 40°C.

14. Use according to claim 12 or 13, wherein the thermoporous 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, at least one of the first substrate and the second substrate being a thermally porous substrate at a temperature of at least 40°C, the seal having a cured layer of a one-part room temperature vulcanizable (RTV) silicone composition, the method comprising: (i) applying at least partially to the surface of the thermoporous substrate an aqueous or solvent-based binder composition at a temperature of at least 40° C., the aqueous or solvent-based binder composition comprising at least 25% by weight of the binder selected from (meth)acrylic resins, poly(meth)acrylic acid, polyvinyl acetate, polyvinyl pyrrolidone, polyvinyl butyral, polyurethane and a silicone resin having the following structure, or a mixture 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 binder composition to allow the binder to coalesce and form a continuous elastic binder film at least on the thermally porous substrate; And then (iii) applying a one-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 surface of the continuous elastic adhesive film and curing it.

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