WO2023230756A1 - Composition d'agent d'étanchéité - Google Patents

Composition d'agent d'étanchéité Download PDF

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Publication number
WO2023230756A1
WO2023230756A1 PCT/CN2022/095929 CN2022095929W WO2023230756A1 WO 2023230756 A1 WO2023230756 A1 WO 2023230756A1 CN 2022095929 W CN2022095929 W CN 2022095929W WO 2023230756 A1 WO2023230756 A1 WO 2023230756A1
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composition
curable silicone
silicone composition
condensation curable
hot porous
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PCT/CN2022/095929
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English (en)
Inventor
Xiuyan WANG
Yi Guo
Qiang Hu
Jiang PENG
Zhiping ZENG
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Dow Silicones Corporation
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Priority to PCT/CN2022/095929 priority Critical patent/WO2023230756A1/fr
Publication of WO2023230756A1 publication Critical patent/WO2023230756A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D183/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers
    • C09D183/14—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/48—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms
    • C08G77/50—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms by carbon linkages

Definitions

  • This relates to a one-part hot porous surface condensation curable silicone composition
  • a one-part hot porous surface condensation curable silicone composition comprising organopolysiloxane polymers having at least two alkoxy groups per molecule and titanate-based or zirconate-based catalysts wherein the hot porous substrate is at a temperature of at least 40°C.
  • the porous substrates may for example be construction materials including stone, marble, brick, concrete, cement and other cementitious substrates. It also relates to a method for applying a one-part hot porous surface condensation curable silicone composition on to a hot porous substrate at a temperature of at least 40°C and the use of said one-part hot porous surface condensation curable silicone composition to treat porous substrates at a temperature of at least 40°C.
  • Condensation curable silicone compositions are well known. Generally, most of such compositions are designed to be room temperature vulcanizable (RTV) , where room temperature is from about 20°C to 25°C. They usually comprise an -OH end-blocked diorganopolysiloxane polymer or an alkoxy end-blocked polydiorganosiloxane which may have an alkylene link between the terminal and penultimate silicon atoms as well as one or more suitable cross-linking agents designed to react with the –OH and/or alkoxy groups and thereby cross-link the composition to form an e.g., elastomeric sealant product and one or more condensation cure catalysts.
  • RTV room temperature vulcanizable
  • Additional ingredients such as reinforcing fillers, non-reinforcing fillers, adhesion promotors, diluents (e.g., plasticisers and/or extenders) , chain extenders, flame retardants, solvent resistant additives, biocides and the like are often also incorporated into these compositions as and when required.
  • diluents e.g., plasticisers and/or extenders
  • chain extenders e.g., flame retardants, solvent resistant additives, biocides and the like are often also incorporated into these compositions as and when required.
  • One-part condensation curing (RTV) silicone compositions are generally utilised to generate skin or diffusion cured silicone elastomers. It is well known to people skilled in the art that alkoxy titanium compounds and /or alkoxy zirconium compounds i.e., alkyl titanates-are suitable catalysts for curing such one component moisture curable silicones.
  • One-part condensation curing silicone compositions are generally designed not to contain any water/moisture in the composition so far as possible, i.e., they are generally stored in a substantially anhydrous form to prevent premature cure during storage before use.
  • Skin or diffusion cure takes place by the formation of a cured skin at the composition/air interface subsequent to the sealant/encapsulant being applied on to a substrate surface. Subsequent to the generation of the surface skin the cure speed is dependent on the speed of diffusion of moisture from the sealant/encapsulant interface with air to the inside (or core) of the layer of silicone composition applied, and the diffusion of condensation reaction by-product/effluent 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.
  • Such one-part condensation curing silicone compositions are applied in a layer that is thinner than typically 15 mm.
  • compositions applied in layers thicker than 15 mm are known to lead to uncured material in the depth of the material, because moisture is very slow to diffuse into very deep sections.
  • the main, if not sole source, of moisture in these compositions are inorganic fillers, e.g., silica or calcium carbonate when present. Said fillers may be rendered anhydrous before inter-mixing with 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.
  • Silicone sealant compositions having at least one Si-alkoxy bond, e.g., Si-methoxy bond in the terminal reactive silyl group and having a polydiorganosiloxane polymeric backbone are widely used for sealants in the construction industry because they have good adhesion, and weather resistance, and the like.
  • the construction industry also prefers one-component compositions to negate the need for mixing ingredients before application and compositions with excellent workability.
  • one-part condensation curable silicone compositions are highly desirable for such purposes, given they have little or no deleterious effects on the porous substrates against which they are applied and subsequently cured, such compositions, especially those comprising organopolysiloxane polymers having at least two alkoxy groups per molecule and titanate-based or zirconate-based catalysts, generate bubbles in the composition during the curing process when the substrate is hot.
  • alkoxy silicone compositions (often used as sealants) are applied onto hot porous substrates at temperatures of at least 40°C, especially hydrophilic hot porous substrates, more and more moisture/water vapor condenses at the interface of the sealant and porous substrates, driven by capillary action and reactivity of moisture with the composition.
  • the bubbling is an issue because the alcohol (methanol) generation speed at the interface is higher than its permeation speed through the bulk curing composition, e.g., sealant composition at the elevated temperature of the substrate.
  • the bubbles are consequently trapped during cure in these conditions not least because of the process by which such compositions cure, i.e., with the initial formation of a skin preventing the escape of the bubbles especially as at elevated temperatures will cause the skin to form quicker than when the sealant cures at room temperature or thereabouts. This is a particular problem when using such compositions as e.g., sealants in countries with hot climates.
  • a one-part hot porous surface condensation curable silicone composition comprising organopolysiloxane polymers having at least two alkoxy groups per molecule and titanate-based or zirconate-based catalysts, wherein the hot porous substrates are at a temperature of at least 40°Cone-part hot porous surface condensation curable silicone composition comprising the following components:
  • each X is independently a hydroxyl group or an alkoxy group
  • each R is an alkyl, alkenyl or aryl group
  • each R 1 is an X group, alkyl group, alkenyl group or aryl group
  • Z is a divalent organic group
  • n 0 or 1
  • y 0, 1 or 2
  • z is an integer such that said organopolysiloxane polymer has a viscosity of from 10,000 to 150,000 mPa. s at 25°C, in an amount of from 30 to 90 weight % (wt. %) of the composition;
  • each group R 3 may be the same or different and is a hydrolysable group selected from alkoxy or acetoxy groups and each R 4 group is the same or different and independently represents an alkyl group having from 1 to 10 carbon atoms, an alkenyl group, an alkynyl group, an aryl group or a fluorinated alkyl group, which silane compound (c) is present in the composition in an amount of from 1 to 10 wt. %of the composition;
  • a silicon containing compound having three or more hydrolysable groups per molecule selected from
  • each R 7 may be the same or different and may be the same as R 5 and each R 8 may be the same or different and may be the same as R 6 , n’ is an integer and z’ is zero or 1; or
  • R 7 , R 8 n’ and z’ are as defined above and R 9 may be the same as R 8 which silicon containing compound (e) is present in the composition in an amount of from 0.1 to 5 wt. %of the composition;
  • a catalyst comprising a titanate-based compound, a zirconate-based compound or a mixture thereof.
  • the total wt. %of the composition is 100 wt. %.
  • the one-part hot porous surface condensation curable silicone composition herein is a one-part condensation curable silicone composition designed to be curable on substrates which are at temperatures of at least 40°C. Such one-part condensation curable silicone composition when cured contain no or minimal visible bubbles.
  • the one-part hot porous surface condensation curable silicone composition comprising organopolysiloxane polymers having at least two alkoxy groups per molecule and titanate-based or zirconate-based catalysts one-part hot porous surface condensation curable silicone composition is curable on a hot porous surface (at least 40°C) with no or minimal bubble generation.
  • the elastomeric sealant material contains no or substantially no trapped bubbles.
  • a one-part hot porous surface condensation curable silicone composition on to the hot porous substrate having a temperature of at least 40°C, wherein the a one-part hot porous surface condensation curable silicone composition comprises the following components: -
  • each X is independently a hydroxyl group or an alkoxy group
  • each R is an alkyl, alkenyl or aryl group
  • each R 1 is an X group, alkyl group, alkenyl group or aryl group
  • Z is a divalent organic group
  • n 0 or 1
  • y 0, 1 or 2
  • z is an integer such that said organopolysiloxane polymer has a viscosity of from 10,000 to 150,000 mPa. s at 25°C, in an amount of from 30 to 90 weight % (wt. %) of the composition;
  • each group R 3 may be the same or different and is a hydrolysable group selected from alkoxy or acetoxy groups and each R 4 group is the same or different and independently represents an alkyl group having from 1 to 10 carbon atoms, an alkenyl group, an alkynyl group, an aryl group or a fluorinated alkyl group, which silane compound (c) is present in the composition in an amount of from 1 to 10 wt. %of the composition;
  • a silicon containing compound having three or more hydrolysable groups per molecule selected from
  • each R 7 may be the same or different and may be the same as R 5 and each R 8 may be the same or different and may be the same as R 6 , n’ is an integer and z’ is zero or 1; or
  • R 7 , R 8 n’ and z’ are as defined above and R 9 may be the same as R 8 which silicon containing compound (e) is present in the composition in an amount of from 0.1 to 5 wt. %of the composition;
  • a method of bonding silicone sealant to a hot porous substrate at a temperature of at least 40°C. comprising the steps of preparing a one-part hot porous surface condensation curable silicone composition as hereinbefore described, contacting a surface of a hot porous substrate at a temperature of at least 40°C. with the one-part hot porous surface condensation curable silicone composition and curing said a one-part hot porous surface condensation curable silicone composition thereby obtaining a silicone sealant bonded to a surface of the hot porous substrate.
  • a sealant bonded to a hot porous substrate at a temperature of at least 40°C obtained or obtainable preparing a one-part hot porous surface condensation curable silicone composition as hereinbefore described, contacting a surface of a hot porous substrate at a temperature of at least 40°C with the one-part hot porous surface condensation curable silicone composition and curing said a one-part hot porous surface condensation curable silicone composition.
  • each X is independently a hydroxyl group or an alkoxy group
  • each R is an alkyl, alkenyl or aryl group
  • each R 1 is an X group, alkyl group, alkenyl group or aryl group
  • Z is a divalent organic group
  • n 0 or 1
  • y 0, 1 or 2
  • z is an integer such that said organopolysiloxane polymer has a viscosity of from 10,000 to 150,000 mPa. s at 25°C, in an amount of from 30 to 90 weight % (wt. %) of the composition;
  • each group R 3 may be the same or different and is a hydrolysable group selected from alkoxy or acetoxy groups and each R 4 group is the same or different and independently represents an alkyl group having from 1 to 10 carbon atoms, an alkenyl group, an alkynyl group, an aryl group or a fluorinated alkyl group, which silane compound (c) is present in the composition in an amount of from 1 to 10 wt. %of the composition;
  • a silicon containing compound having three or more hydrolysable groups per molecule selected from
  • each R 7 may be the same or different and may be the same as R 5 and each R 8 may be the same or different and may be the same as R 6 , n’ is an integer and z’ is zero or 1; or
  • R 7 , R 8 n’ and z’ are as defined above and R 9 may be the same as R 8 which silicon containing compound (e) is present in the composition in an amount of from 0.1 to 5 wt. %of the composition;
  • first substrate and/or second substrate is/are stone, marble, brick, concrete, cement and other cementitious substrates, combinations thereof, or combinations with other non-porous building materials.
  • substituted means one or more hydrogen atoms in a hydrocarbon group has been replaced with another substituent.
  • substituents include, but are not limited to, halogen atoms such as chlorine, fluorine, bromine, and iodine; halogen atom containing groups such as chloromethyl, perfluorobutyl, trifluoroethyl, and nonafluorohexyl; oxygen atoms; oxygen atom containing groups such as (meth) acrylic and carboxyl; nitrogen atoms; nitrogen atom containing groups such as amino-functional groups, amido-functional groups, and cyano-functional groups; sulphur atoms; and sulphur atom containing groups such as mercapto groups.
  • the one-part hot porous surface condensation curable silicone composition which is suitable for application on porous substrates at temperatures of at least 40°C is designed for the purpose of bonding it to the surfaces of hot porous substrates, such as stone, marble, brick, concrete, cement and other cementitious substrates combinations thereof, and combinations with other non-porous building materials.
  • the said one-part hot porous surface condensation curable silicone composition may also be used to bond combinations of the hot porous surfaces together, as well as with other conventional building materials, such as glass and aluminum.
  • the said one-part hot porous surface condensation curable silicone composition is brought into contact with the hot porous surface by conventional means such as by extrusion, coating, injection, knifing and rolling.
  • the one-part hot porous surface condensation curable silicone composition is particularly intended to be used when the surface of the porous substrate onto which it is to be applied is at a temperature of at least 40°C. Porous surfaces which are at a temperature lower than 40°C. may form some bubbles, but the reduction of bubbles is significant at temperatures of 40°C or above, when the method described herein is used.
  • said one-part hot porous surface condensation curable silicone composition is applied to the hot porous substrate, it is exposed to atmospheric moisture causing it to cure to a silicone sealant bonded to the hot porous substrate surface wherein there is a reduction in the number and size of bubbles in the cured silicone sealant compared to if a standard RTV silicone sealant were applied onto a hot porous substrate at 40°C or more.
  • the one-part hot porous surface condensation curable silicone composition as herein described is curable on a hot porous surface (at least 40°C) with a reduction in bubble generation.
  • the undesirable bubbles form primarily at the interface between the hot porous substrate and the cured silicone surface.
  • the temperature of the environment in which this sealant composition is designed cure are significantly higher e.g., >10°C higher than typically designed and as such the cure time and working time for most standard sealant formulations will be shorter than usual.
  • the said one-part hot porous surface condensation curable silicone compositions herein however have increased working time compared to standard sealant compositions at temperatures of 40°C or more. The components of the composition will now be described in more detail.
  • the organopolysiloxane polymer having at least two hydroxyl or hydrolysable groups per molecule
  • each X is independently a hydroxyl group or an alkoxy group, alternatively an alkoxy group.
  • said alkoxy group has between 1 and 10 carbons
  • Illustrative alkoxy groups are methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, t-butoxy, isobutoxy, pentoxy, hexoxy and 2-ethylhexoxy; dialkoxy groups, such as methoxymethoxy or ethoxymethoxy and alkoxyaryloxy, such as ethoxyphenoxy groups;
  • each X is an alkoxy group having from one and six carbons, alternatively having from one and four carbons or alternatively is a methoxy or ethoxy group.
  • Each R group is an alkyl, alkenyl or aryl group, alternatively each R is an alkyl group having from 1 to 6 carbons, an alkenyl group having from 2 to 6 carbons such as vinyl, allyl and hexenyl groups or an aryl group having from 6 to 12 carbons; alternatively each R is an alkyl group having from 1 to 6 carbons, or an aryl group having from 6 to 12 carbons; alternatively each R is an alkyl group having from 1 to 6 carbons, alternatively each R is an ethyl group or a methyl group.
  • R may include substituted aliphatic organic groups such as 3, 3, 3-trifluoropropyl groups aminoalkyl groups, polyaminoalkyl groups, and/or epoxyalkyl groups.
  • Each R 1 is an X group, or and R group, with the proviso that cumulatively at least two X groups and/or R 1 groups per molecule are hydroxyl or hydrolysable groups.
  • each R 1 is an R group. It is possible that some R 1 groups may be siloxane branches off the polymer backbone which branches may have terminal groups as hereinbefore described.
  • Each Z is a divalent organic group, typically an alkylene having from 2 to 10 carbons, such as for example, an ethylene, propylene, butylene, pentylene and/or hexylene group; alternatively, an alkylene group having 2 to 6 carbons, alternatively an alkylene group having from 2 to 5 carbons.
  • Subscript z is an integer such that said organopolysiloxane polymer has a viscosity of from 10,000 to 150,000 mPa. s, alternatively from 30,000 to 140,000mPa. s at 25°C, therefore z is an integer of from approximately 300 to 2000.
  • the viscosity of component (a) may be measured by any suitable method such as in accordance with corporate test method CTM 0050, which is publicly available, and which is based on ASTM D 1084-16 method B, using a Brookfield HBDV-III Ultra Rheometer equipped with a cone-and-plate geometry using spindle 52. All viscosity measurements herein are taken at 25°C unless otherwise indicated.
  • the viscosity may be measured using a Modular Compact Rheometer (MCR) 302 rheometer from Anton Paar GmbH of Graz, Austria with the most suitable settings and plates for the viscosity concerned.
  • MCR Modular Compact Rheometer
  • viscosities in the range of 30,000-160,000 mPa. s may be measured using the MCR 302 rheometer with a 40 mm diameter cone-plate and a shear rate of 1s -1 ; viscosities in the range 2000-30,000 mPa. s may be measured using the MCR 302 rheometer with a 50 mm diameter cone-plate and a shear rate of 1s -1 ; and viscosities in the range 10-2000 mPa. s may be measured using the MCR 302 rheometer with a 75 mm diameter cone-plate and a shear rate of 1s -1 .
  • Component (a) is present in the one-part hot porous surface condensation curable silicone composition in an amount of from 30 to 90 wt. %of the composition, alternatively 35 to 75%, alternatively 35 to 60 wt. %of the composition.
  • Organopolysiloxane polymer (a) can be a single siloxane represented by Formula (1) or it can be mixtures of organopolysiloxane polymers represented by the aforesaid formula. Hence, it may be a "siloxane polymer mixture" so organopolysiloxane polymer (a) is meant to include any individual organopolysiloxane polymer (a) or mixtures of organopolysiloxane polymer (a) .
  • the Degree of Polymerization (i.e., in the above formula substantially z) , is usually defined as the number of monomeric units in a macromolecule or polymer or oligomer molecule of silicone.
  • Synthetic polymers invariably consist of a mixture of macromolecular species with different degrees of polymerization and therefore of different molecular weights.
  • Mn and Mw of a silicone polymer can be determined by gel permeation chromatography (GPC) with precision of about 10-15%using polystyrene standards.
  • the DP is linked to the viscosity of the polymer via Mw, the higher the DP, the higher the viscosity.
  • the number average molecular weight and weight average molecular weight values of component (a) herein may, for example, be determined using a Waters 2695 Separations Module equipped with a vacuum degasser, and a Waters 2414 refractive index detector (Waters Corporation of MA, USA) . The analyses may then be performed using certified grade toluene flowing at 1.0 mL/min as the eluent. Data collection and analyses may be performed using Waters Empower GPC software.
  • One or more reinforcing fillers (b)
  • the one or more reinforcing fillers identified as component (b) herein are selected from precipitated silica, fumed silica, precipitated calcium carbonate, or a mixture of two or more thereof.
  • the surface area of the reinforcing filler (b) is at least 15 m 2 /g in the case of precipitated calcium carbonate measured in accordance with the BET method (ISO 9277: 2010) , alternatively 15 to 50 m 2 /g, alternatively 15 to 25 m 2 /g.
  • Silica reinforcing fillers have a typical surface area of at least 50 m 2 /g in accordance with the BET method (ISO 9277: 2010) .
  • these may have surface areas of from 75 to 400 m 2 /g measured in accordance with the BET method (ISO 9277: 2010) , alternatively of from 100 to 300 m 2 /g in accordance with the BET method (ISO 9277: 2010) .
  • the reinforcing fillers (b) may be hydrophobically treated for example with one or more aliphatic acids, e.g., a fatty acid such as stearic acid or a fatty acid ester such as a stearate, or with organosilanes, organosiloxanes, or organosilazanes hexaalkyl disilazane or short chain siloxane diols to render the filler (s) hydrophobic and therefore easier to handle and obtain a homogeneous mixture with the other adhesive components.
  • one or more aliphatic acids e.g., a fatty acid such as stearic acid or a fatty acid ester such as a stearate
  • organosilanes, organosiloxanes, or organosilazanes hexaalkyl disilazane or short chain siloxane diols to render the filler (s) hydrophobic and therefore easier to handle and obtain a homo
  • organosilanes, organosiloxanes, or organosilazanes may include, but are not restricted to, silanol terminated trifluoropropylmethylsiloxane, silanol terminated vinyl methyl (ViMe) siloxane, silanol terminated methyl phenyl (MePh) siloxane, liquid hydroxyldimethyl-terminated polydiorganosiloxane containing an average from 2 to 20 repeating units of diorganosiloxane in each molecule, hydroxyldimethyl terminated phenylmethyl Siloxane, hexaorganodisiloxanes, such as hexamethyldisiloxane, divinyltetramethyldisiloxane; hexaorganodisilazanes, such as hexamethyldisilazane (HMDZ) , divinyltetramethyldisilazane and tetramethyldi (tri
  • the surface treatment of the fillers makes them easily wetted by component (a) .
  • These surface modified fillers are preferably in a finely divided form and do not clump and can be homogeneously incorporated into the silicone polymer (a) This results in improved room temperature mechanical properties of the uncured compositions.
  • the fillers may be pre-treated or may be treated in situ when being mixed with component (a) . Asmall amount of water can be added together with the silica treating agent (s) as processing aid.
  • the reinforcing fillers (b) may be present in an amount of from 2.5 to 60 %by weight (wt. %) of the one-part hot porous surface condensation curable silicone composition.
  • the selected fillers are precipitated silica and/or fumed silica or a combination thereof
  • the inorganic fillers (b) are present in a range of from about 5.0 to 35 wt. %of the composition, alternatively of from 5 to 30 wt. %of the composition, alternatively of from 5 to 25 wt.%of the composition.
  • reinforcing filler (b) is precipitated calcium carbonate, the composition will tend to include a larger wt.
  • component (b) is a mixture of silica and precipitated calcium carbonate the wt. %will typically somewhere therebetween.
  • Component (c) is a silane having two hydrolysable groups per molecule of the formula
  • Each group R 3 may be the same or different and is a hydroxyl or hydrolysable group.
  • Examples of preferred R 3 groups may be selected from the group of alkoxy or acetoxy groups.
  • the reactable groups are alkoxy groups having from 1 and 10 carbon atoms such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, and t-butoxy groups.
  • Each R 4 group is the same or different and independently represents an alkyl group having from 1 to 10 carbon atoms, an alkenyl group, such as vinyl, propenyl and hexenyl groups.
  • an alkynyl group an aryl group such as phenyl, or a fluorinated alkyl group.
  • Suitable silanes for component (c) include: -alkenyl alkyl dialkoxysilanes such as vinyl methyl dimethoxysilane, vinyl ethyldimethoxysilane, vinyl methyldiethoxysilane and vinylethyldiethoxysilane; dialkyl dialkoxysilanes such as dimethyl dimethoxysilane, diethyldimethoxysilane, dimethyldiethoxysilane and diethyldiethoxysilane; dialkenyl dialkoxysilanes such as divinyl dimethoxysilane, divinyl dimethoxysilane, divinyl diethoxysilane and divinyldiethoxysilane; phenyl alkyl dialkoxysilanes such as phenyl methyl dimethoxysilane, phenyl ethyldimethoxysilane, phenyl methyldiethoxysilane and phenyl ethoxy
  • Component (c) may alternatively diacetoxysilane equivalents to the above or dihydroxy equivalents to the above di 3, 3, 3-trifluoropropyldimethoxysilane.
  • Component (c) may alternatively be a mixture of two or more of the above.
  • Component (c) is present in a range of from 1 to 10 wt. %of the one-part hot porous surface condensation curable silicone composition, alternatively from 1.25 to 7.5 weight %of the composition, alternatively from 1.5 to 4.0 weight %of the composition.
  • TPOS Tetra-n-propoxysilane
  • %of the one-part hot porous surface condensation curable silicone composition alternatively 0.40 to 3.0 wt. %of the composition, alternatively 0.40 to 2.5 wt. %of the composition, alternatively 0.40 to 2.5 wt. %of the composition, alternatively 0.50 to 2.0 wt. %of the composition.
  • Component (e) of the one-part hot porous surface condensation curable silicone composition is a silicon containing compound selected from: -
  • a 1, 3, 5-tris (trialkoxysilylalkyl) isocyanurate for example a 1, 3, 5-tris (trialkoxysilylalkyl) isocyanurate having the following structure : -
  • each R 5 may be the same or different and is a divalent alkylene group having from 2 to 10 carbons, alternatively from 2 to 6 carbons, alternatively from 2 to 5 carbons and each R 6 is the same or different and is an alkyl group having from 1 to 10 carbons alternatively from 1 to 6 carbons, alternatively from 1 to 4 carbons, alternatively a methyl group or an ethyl group.
  • the 1, 3, 5-tris (trialkoxysilylalkyl) isocyanurate may be prepared by the reaction of a chloro-alkyl tri-alkoxy silane with an alkali metal cyanate in a polar non-protic solvent.
  • a preferred 1, 3, 5-tris (trialkoxysilylalkyl) isocyanurate is prepared by the reaction of chloro-propyl tri-methoxy silane with potassium cyanate in a suitable solvent such as dimethylformamide (DMF) .
  • DMF dimethylformamide
  • the silicon containing compound may be (e) (b’) and/or (e) (c’) , wherein (e) (b’) is a siloxane oligomer of the structure
  • each R 7 may be the same or different and may be the same as R 5 and each R 8 may be the same or different and may be the same as R 6 , n’ is an integer and z’ is zero or 1; or
  • R 9 -Si- ( (O-Si (CH 3 ) 2 ) n’ - (R 7 –Si (CH 3 ) 2 –O-Si (CH 3 ) 2 ) z’ –R 7 –Si (OR 8 ) 3 ) 3 where again R 7 , R 8 n’ and z’ are as defined above and R 9 may be the same as R 8 or may be an aryl group or a fluorinated alkyl group.
  • each R 7 may be the same or different and may be a divalent alkylene having from 2 to 5 carbons
  • each R 8 may be the same or different and comprises from 1 and 5 carbons
  • each R 7 is the same and may be the same or different and may be a divalent alkylene having from 2 to 5 carbons
  • each R 8 may be the same or different and comprises from 1 and 5 carbons
  • each R 7 is the same and contains two or three carbons 2 or 3, alternatively 2 carbons
  • each R 8 is the same and has from 1 to 3 carbons, alternatively is methyl or ethyl, alternatively is methyl and z’ is 1.
  • n’ is an integer, alternatively each n’ is an integer of from 1 and 1000, alternatively of from 2 to 750.
  • R 9 is preferably R 8 or R 8 or may be an aryl group or a fluorinated alkyl group.
  • Component (e) is being utilised as a cross-linker and given their structures they are designed to provide cured sealants having both high elasticity and low modulus.
  • each of (e) (a’) (e) (b’) or (e) (c’) have three or more trialkoxy silyl terminal groups per molecule.
  • the silicon containing compounds (e) is present in an amount of from 0.1 to 5 wt. %of the one-part hot porous surface condensation curable silicone composition, alternatively present in an amount of from 0.1 to 4 wt. %of the composition, alternatively in an amount of from 0.1 to 2.5 wt. %of the composition, alternatively in an amount of from 0.1 to 1.5 wt. %of the composition, alternatively in an amount of from 0.1 to 1.0 wt. %of the composition.
  • a catalyst comprising a titanate-based compound, a zirconate-based compound or a mixture thereof (f)
  • Component (f) comprises a condensation catalyst (iv) which increases the speed at which the composition cures.
  • Titanate-based and/or zirconate-based catalysts may comprise a compound according to the general formula Ti [OR 22 ] 4 or Zr [OR 22 ] 4 where each R 22 may be the same or different and represents a monovalent, primary, secondary or tertiary aliphatic hydrocarbon group which may be linear or branched containing from 1 to 10 carbon atoms.
  • the titanate may contain partially unsaturated groups.
  • R 22 examples include but are not restricted to methyl, ethyl, propyl, isopropyl, butyl, tertiary butyl and a branched secondary alkyl group such as 2, 4-dimethyl-3-pentyl.
  • each R 22 is the same, and R 22 is an isopropyl, branched secondary alkyl group or a tertiary alkyl group, in particular, tertiary butyl.
  • Suitable examples include for the sake of example, tetra n-butyl titanate, tetra t-butyl titanate, tetra t-butoxy titanate, tetraisopropoxy titanate and zirconate equivalents.
  • the titanate may be chelated.
  • the chelation may be with any suitable chelating agent such as an alkyl acetylacetonate such as methyl or ethyl acetylacetonate.
  • the titanate may be monoalkoxy titanates bearing three chelating agents such as for example 2-propanolato, tris isooctadecanoato titanate and diisopropoxydiethylacetoacetate titanate or titanium ethyl acetoacetate complexes mixed with a methyl-trimethoxy silane.
  • Component (f) may be present in any suitable amount, such as from 0.05 wt. %to 1.5 wt.
  • %of the one-part hot porous surface condensation curable silicone composition alternatively in an amount of from 0.05 wt. %to 1.25 wt. %of the composition, alternatively in an amount of from 0.1 wt. %to 1.0 wt. %of the composition, alternatively in an amount of from 0.1 wt. %to 0.75 wt. %of the composition.
  • Components (c) + (d) + (e) are present cumulatively in the one-part hot porous surface condensation curable silicone composition in a range of from 1.5 to 18.5 wt. %of the composition.
  • components (c) + (d) + (e) may be present cumulatively in a range of from 1.5 to 10 wt. %of the composition; alternatively, components (c) + (d) + (e) may be present cumulatively in a range of from 2.0 to 7.5 wt. %of the composition; alternatively, components (c) + (d) + (e) may be present cumulatively in a range of from 2.5 to 7.5 wt. %of the composition.
  • Optional additives may be used if required necessary. These may include non-reinforcing fillers, pigments, rheology modifiers, cure modifiers, adhesion promoters, tin (iv) condensation catalysts, and fungicides and/or biocides and the like; It will be appreciated that some of the additives may be included in more than one list of additives. Such additives would then have the ability to function in all the different ways referred to.
  • Non-reinforcing fillers which might be used in addition to component (b) herein include aluminite, calcium sulphate (anhydrite) , gypsum, nepheline, svenite, quartz, calcium sulphate, magnesium carbonate, ground calcium carbonate, clays such as kaolin, aluminium trihydroxide, magnesium hydroxide (brucite) , graphite, copper carbonate, e.g., malachite, nickel carbonate, e.g., zarachite, barium carbonate, e.g., witherite and/or strontium carbonate e.g., strontianite.
  • aluminite calcium sulphate (anhydrite) , gypsum, nepheline, svenite, quartz, calcium sulphate, magnesium carbonate, ground calcium carbonate, clays such as kaolin, aluminium trihydroxide, magnesium hydroxide (brucite) , graphit
  • Aluminium oxide silicates from the group consisting of olivine group; garnet group; aluminosilicates; ring silicates; chain silicates; and sheet silicates.
  • the olivine group comprises silicate minerals, such as but not limited to, forsterite and Mg 2 SiO 4 .
  • the garnet group comprises ground silicate minerals, such as but not limited to, pyrope; Mg 3 Al 2 Si 3 O 12 ; grossular; and Ca 2 Al 2 Si 3 O 12 .
  • Aluminosilicates comprise ground silicate minerals, such as but not limited to, sillimanite; Al 2 SiO 5 ; mullite; 3Al 2 O 3 .2SiO 2 ; kyanite; and Al 2 SiO 5 .
  • the ring silicates group comprises silicate minerals, such as but not limited to, cordierite and Al 3 (Mg, Fe) 2 [Si 4 AlO 18 ] .
  • the chain silicates group comprises ground silicate minerals, such as but not limited to, wollastonite and Ca [SiO 3 ] .
  • the sheet silicates group comprises silicate minerals, such as but not limited to, mica;
  • K 2 AI 14 [Si 6 Al 2 O 20 ] (OH) 4 ; pyrophyllite; Al 4 [Si 8 O 20 ] (OH) 4 ; talc; Mg 6 [Si 8 O 20 ] (OH) 4 ; serpentine for example, asbestos; Kaolinite; Al 4 [Si 4 O 10 ] (OH) 8 ; and vermiculite.
  • Such additional fillers may also be hydrophobically treated in the same manner as component (b) as described above.
  • the non-reinforcing fillers tend to be used to replace some of component (b) , hence when component (b) the reinforcing filler is precipitated calcium carbonate and a non-reinforcing filler is also present in the composition the total amount of precipitated calcium carbonate and non-reinforcing filler will still be no more than the upper limit 60 wt. %of the composition.
  • the composition when component (b) is precipitated calcium carbonate the composition also comprises ground calcium carbonate.
  • the non-reinforcing filler may be present in an amount of from greater than zero to 20 wt. %of the composition.
  • the one-part hot porous surface condensation curable silicone composition as described herein may further comprise one or more pigments and/or colorants which may be added if desired.
  • the pigments and/or colorants may be coloured, white, black, metal effect, and luminescent e.g., fluorescent and phosphorescent. Pigments are utilized to colour the composition as required. Any suitable pigment may be utilized providing it is compatible with the composition herein.
  • pigments and/or coloured (non-white) fillers e.g., carbon black may be utilized in the catalyst package to colour the end sealant product.
  • Suitable white pigments and/or colorants include titanium dioxide, zinc oxide, lead oxide, zinc sulfide, lithophone, zirconium oxide, and antimony oxide.
  • Suitable non-white inorganic pigments and/or colorants include, but are not limited to, iron oxide pigments such as goethite, lepidocrocite, hematite, maghemite, and magnetite black iron oxide, yellow iron oxide, brown iron oxide, and red iron oxide; blue iron pigments; chromium oxide pigments; cadmium pigments such as cadmium yellow, cadmium red, and cadmium cinnabar; bismuth pigments such as bismuth vanadate and bismuth vanadate molybdate; mixed metal oxide pigments such as cobalt titanate green; chromate and molybdate pigments such as chromium yellow, molybdate red, and molybdate orange; ultramarine pigments; cobalt oxide pigments; nickel antimony titanates; lead chrome; carbon black (when present, carbon black will function as both a non-reinforcing filler and colorant) ; lampblack, and metal effect pigments such as aluminium, copper,
  • Suitable organic non-white pigments and/or colorants include phthalocyanine pigments, e.g. phthalocyanine blue and phthalocyanine green; monoarylide yellow, diarylide yellow, benzimidazolone yellow, heterocyclic yellow, DAN orange, quinacridone pigments, e.g.
  • organic reds including metallized azo reds and nonmetallized azo reds and other azo pigments, monoazo pigments, diazo pigments, azo pigment lakes, ⁇ -naphthol pigments, naphthol AS pigments, benzimidazolone pigments, diazo condensation pigment, isoindolinone, and isoindoline pigments, polycyclic pigments, perylene and perinone pigments, thioindigo pigments, anthrapyrimidone pigments, flavanthrone pigments, anthanthrone pigments, dioxazine pigments, triarylcarbonium pigments, quinophthalone pigments, and diketopyrrolo pyrrole pigments.
  • organic reds including metallized azo reds and nonmetallized azo reds and other azo pigments, monoazo pigments, diazo pigments, azo pigment lakes, ⁇ -naphthol pigments, naphthol AS pigments, benzimidazolone pigment
  • the pigments and/or colorants when particulates, have average particle diameters in the range of from 10 nm to 50 ⁇ m, preferably in the range of from 40 nm to 2 ⁇ m.
  • the pigments and/or colorants when present are present in the range of from 2, alternatively from 3, alternatively from 5 to 20 wt. %of the composition.
  • Rheology modifiers which may be incorporated in one-part hot porous surface condensation curable silicone composition include silicone organic co-polymers such as those described in EP0802233 based on polyols of polyethers or polyesters; non-ionic surfactants selected from the group consisting of polyethylene glycol, polypropylene glycol, ethoxylated castor oil, oleic acid ethoxylate, alkylphenol ethoxylates, copolymers or ethylene oxide and propylene oxide, and silicone polyether copolymers; as well as silicone glycols.
  • these rheology modifiers particularly copolymers of ethylene oxide and propylene oxide, and silicone polyether copolymers, may enhance the adhesion to substrates, particularly plastic substrates.
  • the one-part hot porous surface condensation curable silicone composition as hereinbefore described may also comprise 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 comprise aminopropyltriethoxysilane or aminopropyltrimethoxysilane or may comprise:
  • R 10 is an alkyl group containing from 1 to 10 carbon atoms, alternatively R 10 is an alkyl group containing from 1 to 6 carbon atoms, alternatively, R 10 is a methyl or ethyl group.
  • Each R 11 may be the same or different and is each R 11 may be the same or different and is H or R 10 , alternatively each R 11 is R 10 . In one alternative all R 11 groups are the same. When the R 11 groups are the same, it is preferred that they are methyl or ethyl groups.
  • Z 1 is a linear or branched alkylene group having from 2 to 10 carbons, alternatively from 2 to 6 carbons, for example Z 1 may be a propylene group, a butylene group or an isobutylene group.
  • Specific examples include but are not limited to aminopropyltriethoxysilane, aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminoisobutylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -2-aminoethylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminoisobutylethyldimethoxysilane, N- (2-aminoethyl) -2-aminoethylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldiethoxysilane, N- (2-aminoethyl) -2-aminoethylmethyldiethoxysilane, N- (2-amino
  • the adhesion promoter when present is present in an amount of from 0.1 to 3.75%by weight of the composition, alternatively, in an amount of 0.1-2.5 %by weight of the composition, alternatively, in an amount of 0.1-2.0 %by weight of the composition, alternatively, in an amount of 0.2 to 1.0 %by weight of the composition.
  • the only condensation cure catalyst present in the one-part hot porous surface condensation curable silicone composition is component (f) described above.
  • a tin (iv) catalyst may optionally be provided in the composition.
  • the tin (iv) catalyst may be any suitable tin (iv) based condensation cure catalyst.
  • tin (iv) based catalysts examples include tin triflates, dialkyltin 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 dicaprylate, di-n-butyltin di-2, 2-dimethyl octanoate, di-n-butyltin octanoate, di-n-butyltin dilaurate (DBTDL) , di-n-butyltin distearate, di-n-butyltin dimaleate, di-n-butyltin dioleate
  • said tin (iv) based condensation catalyst may be present in an amount of from 0.001 to 0.1 %inclusive by weight (wt. %) of the composition. It was found that whilst not essential, the use of a small amount of a tin (iv) catalyst could be utilised to speed up cure e.g., tack free time (TFT) if desired. That said, in one embodiment no tin (iv) catalyst is present in the composition.
  • TFT tack free time
  • UV and/or light stabilizers UV and/or light stabilizers
  • UV and/or light stabilizers may include, for the sake of example include benzotriazole, ultraviolet light absorbers and/or hindered amine light stabilizers (HALS) such as the product line from Ciba Specialty Chemicals Inc.
  • HALS hindered amine light stabilizers
  • Biocides may additionally be utilized in the composition if required. It is intended that the term "biocides” includes bactericides, fungicides and algicides, and the like. Suitable examples of useful biocides, which may be utilized in compositions as described herein, include, for the sake of example:
  • Carbamates such as methyl-N-benzimidazol-2-ylcarbamate (carbendazim) and other suitable carbamates, 10, 10'-oxybisphenoxarsine, 2- (4-thiazolyl) -benzimidazole, N- (fluorodichloromethylthio) phthalimide, diiodomethyl p-tolyl sulfone, if appropriate in combination with a UV stabilizer, such as 2, 6-di (tert-butyl) -p-cresol, 3-iodo-2-propinyl butylcarbamate (IPBC) , zinc 2-pyridinethiol 1-oxide, triazolyl compounds and isothiazolinones, such as 4, 5-dichloro-2- (n-octyl) -4-isothiazolin-3-one (DCOIT) , 2- (n-octyl) -4-isothiazolin-3-one (OIT) and n-buty
  • biocides might include for example Zinc Pyridinethione, 1- (4-Chlorophenyl) -4, 4-dimethyl-3- (1, 2, 4-triazol-1-ylmethyl) pentan-3-ol and/or 1- [ [2- (2, 4-dichlorophenyl) -4-propyl-1, 3-dioxolan-2-yl] methyl] -1H-1, 2, 4-triazole.
  • the fungicide and/or biocide may suitably be present in an amount of from 0 to 0.3wt. %of the composition and may be present in an encapsulated form where required such as described in EP2106418.
  • the one-part hot porous surface condensation curable silicone composition which is suitable for application on porous substrates at a temperature of at least 40°C described herein may comprise (a) an organopolysiloxane polymer having at least two hydroxyl or hydrolysable groups per
  • each X is independently a hydroxyl group or an alkoxy group
  • each R is an alkyl, alkenyl or aryl group
  • each R 1 is an X group, alkyl group, alkenyl group or aryl group
  • Z is a divalent organic group
  • n 0 or 1
  • y is 0, 1 or 2
  • z is an integer such that said organopolysiloxane polymer has a viscosity of from 10,000 to 150,000 mPa. s at 25°C, alternatively from 30,000 to 140,000mPa. s at 25°C, in accordance with Corporate test method CTM 0050, which is publicly available, and which is based on ASTM D 1084-16 method B, using a Brookfield HBDV-III Ultra Rheometer equipped with a cone-and-plate geometry using spindle 52, in an amount of from 30 to 90 wt. %of the composition, alternatively 35 to 75%, alternatively 35 to 60 wt. %of the composition;
  • the composition will tend to include a larger wt. %of the composition, e.g. from 25 to 60 wt. %, alternatively of from 30 to 60 wt. %of the composition, alternatively of from 35 to 55 wt. %of the composition;
  • each group R 3 may be the same or different and is a hydrolysable group selected from alkoxy or acetoxy groups and each R 4 group is the same or different and independently represents an alkyl group having from 1 to 10 carbon atoms, an alkenyl group, an alkynyl group, an aryl group or a fluorinated alkyl group present; in a range of from 1 to 10 wt. %of the composition, alternatively from 1.25 to 7.5 weight %of the composition, alternatively from 1.5 to 4.0 weight %of the composition;
  • Tetra-n-propoxysilane in an amount of from 0.40 to 3.5 wt. %of the composition, alternatively 0.40 to 3.0 wt. %of the composition, alternatively 0.40 to 2.5 wt. %of the composition, alternatively 0.40 to 2.5 wt. %of the composition, alternatively 0.50 to 2.0 wt. %of the composition;
  • a silicon containing compound having three or more hydrolysable groups per molecule selected from
  • R 7 , R 8 n’ and z’ are as defined above and R 9 may be the same as R 8 ; present in an amount of from 0.1 to 5 wt. %of the composition, present in an amount of from 0.1 to 4 wt. %of the composition, alternatively in an amount of from 0.1 to 2.5 wt. %of the composition, alternatively in an amount of from 0.1 to 1.5 wt. %of the composition, alternatively in an amount of from 0.1 to 1.0 wt. %of the composition; and
  • a catalyst comprising a titanate-based compound, a zirconate-based compound or a mixture thereof in an amount of from 0.05 wt. %to 1.5 wt. %of the composition, alternatively in an amount of from 0.05 wt. %to 1.25 wt. %of the composition, alternatively in an amount of from 0.1 wt. %to 1.0 wt. %of the composition, alternatively in an amount of from 0.1 wt. %to 0.75 wt. %of the composition.
  • the one-part hot porous surface condensation curable silicone composition may comprise any combination of the above providing that the total composition of ingredients (a) to (f) together with any other optional ingredients included in the composition has a value of 100 wt. %of the composition. It will be appreciated that component (d) and component (e) are different.
  • components (c) + (d) + (e) are present cumulatively in the one-part hot porous surface condensation curable silicone composition in a range of from 1.5 to 18.5 wt. %of the composition.
  • components (c) + (d) + (e) may be present cumulatively in a range of from 1.5 to 10 wt. %of the composition;
  • components (c) + (d) + (e) may be present cumulatively in a range of from 2.0 to 7.5 wt. %of the composition;
  • components (c) + (d) + (e) may be present cumulatively in a range of from 2.5 to 7.5 wt. %of the composition.
  • a method of bonding silicone sealant to a hot porous substrate at a temperature of at least 40°C. comprising the steps of preparing a one-part hot porous surface condensation curable silicone composition as hereinbefore described, contacting a surface of a hot porous substrate at a temperature of at least 40°C. with the one-part hot porous surface condensation curable silicone composition and curing said one-part hot porous surface condensation curable silicone composition.
  • the one-part hot porous surface condensation curable silicone composition as described above may be prepared by mixing all the ingredients together. Preferably once mixed, unless to be used immediately, the composition is sealed in one or more moisture-tight containers and is stored.
  • filler (b) and/or pigment when present is/are first mixed into the polymer (a) , optionally, if required in combination with a hydrophobic treating agent so that the filler and optional pigment may be hydrophobically treated in situ during the mixing into the polymer. Once the filler is adequately mixed into the polymer (and if desired has been hydrophobically treated) then the remaining components are added in any suitable order to make the complete composition.
  • the process for making the one-part hot porous surface condensation curable silicone composition may comprise the following steps: -
  • premix 1 Premix components (c) , (d) , (e) and (f) to form premix 1;
  • premix 1 was then added into the polymer base and is mixed into the base, under vacuum if deemed necessary;
  • the pigment When optional pigment is to be used the pigment may be introduced prior to the filler (s) or simultaneously with the fillers resulting in a pigmented polymer base after the completion of step 1 above.
  • Optional ingredients such as adhesion promoter (s) may also be added into premix 1.
  • a second pre-mix may be prepared comprising e.g., optional ingredients such as adhesion promoter and the optional tin (iv) catalyst.
  • two premixes When two premixes are desired these may be split so that components (d) , (e) (f) and part of (c) are mixed together in one premix, e.g.
  • premix 1a and the remainder of component (c) , optional adhesion promoter and tin (iv) catalyst are mixed together in a second premix, premix 2 and the two premixes can be introduced and mixed into the composition in any order, for example premix 1a may be added first, mixed in and the premix 2 can be added and mixed in to complete the composition.
  • Bubbling on stone, marble, brick, concrete, cement and other cementitious substrates, particularly stone substrates during summer season is a common issue for one-part room temperature vulcanisable (RTV) silicone compositions, particularly after storage, containing alkoxy terminated polymers (a) and titanate/zirconate catalysts (f) .
  • RTV room temperature vulcanisable
  • alkoxy terminated polymers and titanate and/or zirconate catalysts are applied onto porous surfaces which are at a temperature lower than 40°Csome bubbles are formed.
  • the generation of bubbles is far more marked and consequently far more easily observed when the substrates are at temperatures of 40°C or more, usually due to the direct sunlight.
  • the bubbling may be caused by the generation of alcohols, especially methanol during the cure process at hot temperatures with the porous nature of the substrate acting as some form of accelerator with the pores of the porous substrates acting as nucleation points for the formation of bubbles which are then trapped during cure within the body of the sealant, not least because of the process by which such compositions cure, i.e. with the initial formation of a skin preventing the escape of the bubbles especially as at elevated temperatures cure will be accelerated causing the skin to form quicker than when the sealant cures at room temperature or thereabouts.
  • the one-part hot porous surface condensation curable silicone composition as described in the present disclosure may be applied on to hot porous substrates having a temperature of at least 40°C by any suitable means such as by extrusion, coating, injection, knifing and rolling, typically dependent on the viscosity and ability to flow on the substrate surface. Irrespective of the means of application, it was found that either no bubbles were formed or comparatively much fewer bubbles were formed at the interface between the porous substrate surface and the sealant applied when compared to standard one-part room temperature vulcanisable (RTV) silicone compositions.
  • RTV room temperature vulcanisable
  • An additional advantage of the present one-part hot porous surface condensation curable silicone compositions was that it allowed the user to have an increased working time compared to standard sealant compositions which tend to cure very quickly at the temperatures concerned because after said one-part hot porous surface condensation curable silicone composition is applied to the hot porous substrate, it is exposed to atmospheric moisture causing it to cure and adhere to the initially hot porous substrate surface.
  • an elastomeric sealant material which is the cured product of the one-part hot porous surface condensation curable silicone composition as hereinbefore described.
  • a sealant bonded to a hot porous substrate at a temperature of at least 40°C obtained or obtainable by preparing a one-part hot porous surface condensation curable silicone composition as hereinbefore described, contacting a surface of a hot porous substrate at a temperature of at least 40°C. with the one-part hot porous surface condensation curable silicone composition and curing said one-part hot porous surface condensation curable silicone composition.
  • the one-part hot porous surface condensation curable silicone composition herein may be further managed to engineer a low modulus one-part hot porous surface condensation curable silicone composition.
  • Low modulus silicone sealant compositions are preferably “gunnable” i.e., they have a suitable extrusion capability and given the resulting sealant imparts a movement capability to the post-cured sealant material of greater than 25 %and indeed in one exceptional case greater than 50%as measured in accordance with ASTM C920 50%.
  • the one-part hot porous surface condensation curable silicone composition suitable for application on porous substrates at a temperature of at least 40°C as hereinbefore described may be a gunnable sealant composition used for
  • seal applications such as sealing the edge of a lap joint in a construction membrane
  • the laminate structure produced is not limited to these three layers. Additional layers of cured sealant and substrate may be applied.
  • the layer of gunnable sealant composition in the laminate may be continuous or discontinuous.
  • a one-part hot porous surface condensation curable silicone composition as hereinbefore described suitable for application on porous substrates at a temperature of at least 40°C may be applied on to any suitable substrate but given the application is particularly designed for application on substrates such as stone, marble, brick, concrete, cement and other cementitious substrates combinations thereof, and combinations with other non-porous building materials such as metals e.g. aluminium and steel and glass which can reach temperatures of at least 40°C in hot countries during the summer period when it is hottest as a stain-resistant weather sealing sealant material for construction and the like applications.
  • the one-part hot porous surface condensation curable silicone composition as hereinbefore described may therefore provide a silicone sealant which may be of a low-modulus type having high movement capabilities.
  • the composition herein is clear, i.e., transparent and/or translucent and is non-staining (clean) on construction substrates such as said granite, limestone, marble, masonry and glass which can reach temperatures of at least 40°C in hot countries during the summer period when it is hottest.
  • the Low modulus nature of the silicone elastomer produced upon cure of the one-part hot porous surface condensation curable silicone composition when designed to be low modulus described herein makes the elastomer effective at sealing joints which may be subjected to movement for any reason, because compared to other cured sealants (with standard or high modulus) lower forces are generated in the cured sealant body and transmitted by the sealant to the substrate/sealant interface due to expansion or contraction of the joint enabling the cured sealant to accommodate greater joint movement without failing cohesively or interfacially (adhesively) or cause substrate failure.
  • porous surface condensation curable silicone composition as a sealant suitable for application on porous substrates at elevated temperatures, i.e., at greater than 40°C such as stone, marble, brick, concrete, cement and other cementitious substrates combinations thereof as well as in combinations with other non-porous building materials in the facade, insulated glass, window construction and construction fields in hot countries.
  • the porous substrates may be particularly preferred for use on stone as a weather seal.
  • compositions of comparative 1 (C. 1) and Examples 1 to 4 (Ex. 1 to Ex. 4) are provided below in Table 1.
  • the polymer was a (MeO) 3 Si-CH 2 -CH 2 -terminated polydimethylsiloxane polymer a viscosity of approximately 65,000 mPa. s at 25°C;
  • PCC Precipitated calcium carbonate filler
  • the PCC was an ultrafine precipitated calcium carbonate coated with fatty acids sold under the trade name Hakuenka TM CCR -S by Shiraishi Kogyo Kaisha, Ltd;
  • GCC Ground calcium carbonate
  • Catalyst 1 was Tyzor TM PITA SM which is an 80: 20 wt. %mixture of Diisopropoxy-bisethylacetoacetatotitanate and methyltrimethoxy silane and is commercially available from Dorf Ketal Speciality Catalysts LLC of Texas USA.
  • composition in Table 1 was prepared using the following process:
  • a premix 1 was prepared separately by mixing the tris (3-trimethoxysilylpropyl) isocyanurate, TPOS and of the VMDM together with the titanate catalyst;
  • the VMDM is split between two premixes premix 1 as above and premix 2 in which the remaining VMDM was mixed together with the 3- (2-aminoethyl) -aminopropyltriethoxysilane and DOTDL to form a second premix, premix 2; when the tin catalyst is not present but the adhesion promoter is, then the adhesion promoter is introduced into premix 1;
  • premix 1 was then added into the pigmented silicone polymer base resulting from step 2 and was mixed therewith at 400rpm for a further 5 mins before premix 2 was added (if required) , after which the mixing was increased to 800 rpm and mixing continued under a vacuum of -70 kPa for 20 min;
  • Samples of the sealant compositions depicted in Table 1 above were aged at a temperature of 50°Cfor two weeks in the cartridges in which they were packaged before being applied on to granite substrate samples which were at a temperature of approximately 50°C at the time of sealant application.
  • the aging period was chosen as an accelerated test to mimic the sealant shelf life.
  • the bubbling issue mainly occurs when sealant stored over 5-6 months. All fresh samples showed no substantial bubbling issue; thus, the aged samples were used for the validation of mitigation methods or compositions.
  • the amount of bubbles present in the cured sealant was visually assessed on a scale of from 1 (no or minimal bubbling observed) to 5 wherein significant bubbling was observed which resulted in poor adhesion between the granite substrate and the cured sealant.
  • the scoring criteria for the bubbling status is as follows: -
  • TFT Tack free time
  • Extrusion Rate was measured following Dow’s CTM 0364. It is designed to determine the rate at which a material will extrude through a standard nozzle under a specified pressure and is based on MIL (Military specification) MIL-S-8802D. Results are provided in g/min.
  • Cure in depth was measured following Dow’s CTM 0663 and measures the depth of cure of a sample by measuring how far below the surface a curing material has hardened in a specified time. Results were taken after 1 day and are provided in mm.
  • Elongation at Break was measured following Dow’s CTM 0137 A which is based on ASTM D 412 and used die C. Results were provided in %.
  • Shore A Durometer was measured following Dow’s CTM 099 which is based on ASTM D 2240. All the above corporate test (CTM) methods are available to the public from Dow Silicones Corporation upon request.
  • Table 3b Physical Properties of C. 1 and Ex. 3 after aging for a period of 2 weeks at 50°C
  • Table 3c Physical Properties of C. 1 and Ex. 3 after aging for a period of 4 weeks at 50°C
  • Table 4 physical properties testing in accordance with Chinese National Standard GB/T 23261-2009
  • the elastic recovery test was undertaken on a sample having been cured at room temperature for 28 days. The sample was extended to a 100%extension and then released and the elastic recovery was determined.
  • Adhesive failure is interfacial bond failure between an adhesive and an adherend. Cohesive failure occurs when a fracture allows a layer of adhesive to remain on both surfaces.
  • Cohesive failure occurs when a fracture allows a layer of adhesive to remain on both surfaces.
  • CF Cohesive failure
  • a mixed failure mode may be observed; that is some areas peel-off (i.e., AF) while some remain covered with coating (i.e., CF) .
  • the portions of surface displaying CF %CF
  • the sealant composition in accordance with this disclosure showed good adhesion on various substrates.
  • the developed one-part alkoxy clean sealant also showed high movement capability passing both ASTM C920 50%and GB/T 23261 50HM) .

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  • Life Sciences & Earth Sciences (AREA)
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Abstract

Composition de silicone durcissable par condensation de surface poreuse chaude en une partie comprenant des polymères d'organopolysiloxane comprenant au moins deux groupes alcoxy par molécule et des catalyseurs à base de titanate ou à base de zirconate, le substrat poreux chaud étant à une température d'au moins 40 °C. Les substrats poreux peuvent par exemple être des matériaux de construction, notamment la pierre, le marbre, la brique, le béton, le ciment et d'autres substrats à base de ciment. L'invention concerne également un procédé d'application d'une composition de silicone durcissable par condensation de surface poreuse chaude en une partie sur un substrat poreux chaud à une température d'au moins 40 °C et l'utilisation de ladite composition de silicone durcissable par condensation de surface poreuse chaude en une partie pour traiter des substrats poreux à une température d'au moins 40 °C.
PCT/CN2022/095929 2022-05-30 2022-05-30 Composition d'agent d'étanchéité WO2023230756A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0802233A2 (fr) 1996-04-17 1997-10-22 Dow Corning S.A. Compositions d'organosiloxane
EP2106418A1 (fr) 2006-12-28 2009-10-07 THOR GmbH Masses de collage et d'étanchéité présentant un apprêt antimicrobien
WO2021133622A1 (fr) * 2019-12-23 2021-07-01 Dow Silicones Corporation Composition d'agent d'étanchéité

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0802233A2 (fr) 1996-04-17 1997-10-22 Dow Corning S.A. Compositions d'organosiloxane
EP2106418A1 (fr) 2006-12-28 2009-10-07 THOR GmbH Masses de collage et d'étanchéité présentant un apprêt antimicrobien
WO2021133622A1 (fr) * 2019-12-23 2021-07-01 Dow Silicones Corporation Composition d'agent d'étanchéité

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