Hydrosilylation curing inhibitors and their uses

Abstract

The present disclosure relates to hydrosilylation-curable silicone rubber compositions having a polyorganosiloxane crosslinker containing at least two or at least three terminal silicon-bonded hydrogen groups and one or more hydrosilylation cure inhibitor compounds selected from multiacrylates having at least three acrylate groups per molecule. Cured products obtained from the curing of such compositions, which may include elastomeric products, are also disclosed.

Description

[Technical field]

[0001] The present disclosure relates to a hydrosilylation curable silicone composition, comprising an inhibitor compound suitable for inhibiting the curing of the hydrosilylation curable silicone composition.The inhibitor compound is a multiacrylate that contains at least three acrylate groups per molecule.Also disclosed herein is a cured material that is the product of curing such a composition, for example, including an elastomeric material.

[0002] One of the most important methods for curing silicone rubber compositions is by hydrosilylation (also called addition cure) reaction route, in which polyorganosiloxane polymers, such as polydiorganosiloxane polymers with unsaturated organic groups, typically alkenyl and / or alkynyl groups, react with one or more crosslinking molecules containing multiple silicone-bonded hydrogen (-Si-H) bonds in the presence of a suitable curing agent.The curing agent is usually selected from the platinum metal group (platinum, ruthenium, osmium, rhodium, iridium, and palladium), or one or more compounds of such metals.Platinum and rhodium compounds are preferred due to the high activity levels of these catalysts in hydrosilylation reactions.

[0003] Many of these curing agents, especially in the presence of platinum and rhodium compounds, begin curing as soon as the components are mixed together, even at room temperature. The rapidity of the reaction necessitates precautions to provide some control over the reaction process. These tend to involve long-term storage of the composition in multiple parts (binary compositions are the most common, one containing the unsaturated polysiloxane and hydrosilylation catalyst, the other the organohydrogenpolysiloxane crosslinker).

[0004] Additionally or alternatively, a cure inhibitor is incorporated into the composition to provide additional control over the cure process, if necessary. The cure inhibitor may be stored in either or both of such binary compositions, provided that it is not adversely affected by other ingredients in the relevant part, but is usually present in the part containing the crosslinker. The hydrosilylation inhibitor may effectively inhibit or delay the catalyst from catalyzing the hydrosilylation reaction. However, once the hydrosilylation inhibitor loses its inhibiting function, the hydrosilylation reaction occurs rapidly. Thus, the composition may be stored for long periods of time, especially when divided into two parts at or near room temperature.

[0005] A wide variety of cure inhibitors have been proposed. These include dialkylformamides, thioamides, alkylthioureas, organophosphorus compounds, benzotriazoles, nitriles, acetylenic alcohols, tris-triorganosilylamines, tetramethylguanidine carboxylates, aminoalkylalkoxysilanes, isocyanurates, diaziridines, higher alkylamines, dialkylmaleic esters, and dialkylacetylenedicarboxylates. Of these, acetylenic alcohol compounds such as ethynylcyclohexanol (ETCH) are the most commonly used. With these systems, fast cure rates (seconds to minutes) at high temperatures can be achieved in combination with long pot lives (hours to days) at room temperature.

[0006] It is known that acrylic or methacrylic compounds and derivatives, such as alkylene glycol esters, for example alkylene glycol esters of diacrylic acid or alkylene glycol esters of dimethacrylic acid, are used in hydrosilylation curable silicone rubber compositions to increase their adhesion (adhesion promoters).In addition, it is also known that acrylates, when present in hydrosilylation curable silicone rubber compositions, can chemically participate in hydrosilylation reactions (e.g., with silicon-bonded hydrogen groups (-Si-H)) in crosslinkers, and thus crosslink to silicone elastomers during curing.This covalent bond to the crosslinked silicone matrix is ​​beneficial for achieving strong adhesion, but current theory suggests that acrylates can strongly interfere with hydrosilylation curing, making it difficult to inhibit these systems by conventional approaches.

[0007] Unexpectedly, it has now been found that while compounds having one or two acrylate groups are suitable for use as adhesion promoters, compounds having three or more, i.e., at least three, acrylate groups per molecule function as hydrosilylation cure inhibitors, particularly for hydrosilylation-curable silicone rubber compositions, and that the crosslinker used in the composition is a polyorganosiloxane having three or more silicon-bonded hydrogen (-Si-H) groups per molecule, each -Si-H group being a terminal -Si-H group, sometimes written as an M(H) group.

[0008] A hydrosilylation-curable silicone composition is provided, which comprises: (A) one or more polyorganosiloxanes containing at least two unsaturated groups per molecule, the unsaturated groups being selected from alkenyl and alkynyl groups, and having a viscosity in the range of 1000 mPa.s to 200,000 mPa.s at 25°C; (B) a polyorganosiloxane containing at least two, alternatively at least three, terminal silicon-bonded hydrogen groups (-Si-H); (C) at least one hydrosilylation catalyst; (D) a hydrosilylation cure inhibitor consisting of or including a multiacrylate compound having at least three acrylate groups per molecule.

[0009] Also provided is a silicone elastomer that is the cured product of the above hydrosilylation-curable silicone composition.

[0010] Also provided herein is the use of a multiacrylate compound having at least three acrylate groups per molecule as a hydrosilylation cure inhibitor (D) in a composition otherwise comprising: (A) one or more polyorganosiloxanes containing at least two unsaturated groups per molecule, the unsaturated groups being selected from alkenyl and alkynyl groups, and having a viscosity in the range of 1000 mPa.s to 200,000 mPa.s at 25°C; (B) a polyorganosiloxane containing at least two, alternatively at least three, terminal silicon-bonded hydrogen groups (-Si-H); (C) at least one hydrosilylation catalyst.

[0011] Surprisingly, it has been found that while monoacrylate molecules, diacrylate molecules and methacrylates appear to function well as adhesion promoters, they do not appear to have an inhibiting and / or retarding effect on the hydrosilylation curing compositions containing component (B) herein, whereas multiacrylates having at least three acrylate groups per molecule of component (D) described herein do. Thus, for the avoidance of doubt, component (D) herein does not consist of monoacrylates, diacrylates or methacrylates.

[0012] Additionally, component (B) does not consist of crosslinkers that contain only non-terminal silicon-bonded hydrogen groups, sometimes referred to as D(H) groups.

[0013] Component (A) Component (A) is a polyorganosiloxane, such as a polydiorganosiloxane, having at least two unsaturated groups per molecule, the unsaturated groups being selected from alkenyl groups, alkynyl groups, or a mixture of alkenyl and alkynyl groups, or alternatively, component (A) has at least three unsaturated groups per molecule selected from alkenyl groups, alkynyl groups, or a mixture of alkenyl and alkynyl groups.

[0014] The unsaturated groups of component A) may be at the terminal, pendant, or both positions of component A). For example, the unsaturated groups may be alkenyl and / or alkynyl groups. The alkenyl groups may have 2 to 30, alternatively 2 to 24, alternatively 2 to 20, alternatively 2 to 12, alternatively 2 to 10, alternatively 2 to 6 carbon atoms. The alkenyls are exemplified by, but are not limited to, vinyl, allyl, methallyl, propenyl, and hexenyl groups. The alkynyl groups may have 2 to 30, alternatively 2 to 24, alternatively 2 to 20, alternatively 2 to 12, alternatively 2 to 10, alternatively 2 to 6 carbon atoms. The alkynyls may be exemplified by, but are not limited to, ethynyl, propynyl, and butynyl groups.

[0015] Component (A) has a plurality of units of formula (I): R a SiO (4-a) / 2 (I), wherein each R is independently selected from an aliphatic hydrocarbyl group, an aromatic hydrocarbyl group, or an organyl group (i.e., any organic substituent having one free valence at a carbon atom, regardless of the type of functional group). Saturated aliphatic hydrocarbyls are exemplified by, but are not limited to, alkyl groups such as methyl, ethyl, propyl, pentyl, octyl, undecyl, and octadecyl, and cycloalkyl groups such as cyclohexyl. Unsaturated aliphatic hydrocarbyls are exemplified by, but are not limited to, the alkenyl and alkynyl groups listed above. Aromatic hydrocarbon groups are exemplified by, but are not limited to, phenyl, tolyl, xylyl, benzyl, styryl, and 2-phenylethyl. Organyl groups are exemplified by, but are not limited to, halogenated alkyl groups (except fluoro-containing groups) such as chloromethyl and 3-chloropropyl, nitrogen-containing groups such as amino, amido, imino, and imido groups, oxygen-containing groups such as polyoxyalkylene, carbonyl, alkoxy, and hydroxyl groups. Further organyl groups may include sulfur-, phosphorus-, and boron-containing groups. The subscript "a" is 0, 1, 2, or 3.

[0016] Siloxy units may be described in contractions (abbreviations), i.e., "M", "D", "T", and "Q", where R is a methyl group (further teachings on silicone nomenclature can be found in Walter Noll, Chemistry and Technology of Silicones, dated 1962, Chapter I, pages 1-9). M units are siloxy units where a=3, i.e., RSiO 1 / 2 and D units are siloxy units where a=2, i.e., RSiO 2 / 2 where T units are siloxy units where a=1, i.e., RSiO 3 / 2 and Q units are siloxy units where a=0, i.e., SiO 4 / 2The polyorganosiloxanes, such as the polydiorganosiloxanes of component (A), are substantially linear, but may contain a proportion, but not all, of the branching due to the presence of T units (as described above) within the molecule, so that the average value of a in structure (I) is about 2.

[0017] Examples of typical groups on component (A) include primarily alkenyl, alkynyl, alkyl, and / or aryl groups, or alkenyl, alkyl, and / or aryl groups, which may be in pendant positions (on D or T siloxy units) or may be terminal (on M siloxy units).

[0018] The silicon-bonded organic groups bonded to component (A) other than alkenyl groups are typically selected from monovalent saturated hydrocarbon groups containing from 1 to 10 carbon atoms and monovalent aromatic hydrocarbon groups typically containing from 6 to 12 carbon atoms, which are unsubstituted or substituted with groups that do not interfere with the curing of the compositions of the invention, such as halogen atoms. Preferred species of silicon-bonded organic groups are, for example, alkyl groups such as methyl, ethyl, and propyl, and aryl groups such as phenyl.

[0019] Component (A) may be selected from, for example, polydimethylsiloxanes, alkylmethylpolysiloxanes, alkylarylpolysiloxanes, or copolymers thereof, containing alkenyl and / or alkynyl groups (reference to alkyl means an alkyl group having two or more carbons), and may have any suitable end groups, which may be, for example, trialkyl-terminated, alkenyldialkyl-terminated, alkynyldialkyl-terminated, or terminated with any other suitable combination of end groups, provided that each polymer contains at least two unsaturated groups selected from alkenyl and alkynyl groups per molecule. In one embodiment, the end groups of such polymers do not have silanol end groups.

[0020] Thus, component (A) may be, for example: dialkylalkenyl-terminated polydimethylsiloxanes, such as dimethylvinyl-terminated polydimethylsiloxanes, dialkylalkenyl-terminated dimethylmethylphenylsiloxanes, such as dimethylvinyl-terminated dimethylmethylphenylsiloxanes, trialkyl-terminated dimethylmethylvinylpolysiloxanes, dialkylvinyl-terminated dimethylmethylvinylpolysiloxane copolymers, and dialkylvinyl-terminated methylphenylpolysiloxanes; dialkylalkenyl-terminated methylvinylmethylphenylsiloxane, dialkylalkenyl-terminated methylvinyldiphenylsiloxane, dialkylalkenyl-terminated methylvinylmethylphenyldimethylsiloxane, trimethyl-terminated methylvinylmethylphenylsiloxane, trimethyl-terminated methylvinyldiphenylsiloxane, or trimethyl-terminated methylvinylmethylphenyldimethylsiloxane.

[0021] In these embodiments, the polyorganosiloxanes of Component A are typically flowable liquids, such as polydiorganosiloxanes having at least two unsaturated groups per molecule at a temperature of 25° C. Generally, the polyorganosiloxanes of Component A have a viscosity of from 1000 MPa.s to 200,000 MPa.s at 25° C., alternatively from 1000 MPa.s to 150,000 MPa.s at 25° C., alternatively from 1000 MPa.s to 100,000 MPa.s at 25° C., alternatively from 1000 MPa.s to 75,000 MPa.s at 25° C. Viscosity may be measured at 25° C. using either a Brookfield™ rotational viscometer with spindle LV-4 (designed for viscosities in the range of 1,000 to 2,000,000 MPa.s) for viscosities below 1000 MPa.s, or a Brookfield™ rotational viscometer with spindle LV-1 (designed for viscosities in the range of 15 to 20,000 MPa.s), and the speed, i.e., shear rate, may be adjusted according to the polymer viscosity, e.g., from 0.005 s -1 From 1s -1 (0.3~60rpm) according to (in this case 1s -1 is preferred), and adapt it.

[0022] Component (B) is a crosslinker in the form of a polyorganosiloxane containing at least two, alternatively at least three, terminal silicon-bonded hydrogen (-Si-H) groups per molecule. Having at least two, alternatively at least three, terminal -Si-H groups means having at least two, alternatively at least three, M units, i.e., RSiO 1 / 2 is meant to have the units M(H) where one R is hydrogen, which is sometimes identified in the literature as M(H).

[0023] Typically, component (B) contains three or more terminal -Si-H groups, whereby the hydrogen atoms can react with the unsaturated alkenyl or alkynyl groups in component (A) to form a network structure therewith, thereby curing the composition. Alternatively, when component (A) has more than (>) two alkenyl or alkynyl groups per molecule, some or all of component (B) may have two terminal -Si-H per molecule.

[0024] The molecular structure of the polyorganosiloxane containing at least two or three terminal -Si-H groups per molecule (B) is not particularly limited, and may be linear, partially branched linear, cyclic, or silicone resin-based.

[0025] Examples of silicon-bonded organic groups used in component (B) may be exemplified by alkyl groups such as methyl, ethyl, propyl, butenyl, pentenyl, hexyl, and the like; aryl groups such as phenyl, tolyl, xylyl, and the like; and halogenated alkyl groups such as 3-chloropropyl, 3,3,3-trifluoropropyl, and the like; with methyl and phenyl groups being preferred.

[0026] Examples of polyorganosiloxanes containing at least two or three terminal (M(H)) silicon-bonded hydrogen (-Si-H) groups per molecule (B) include, but are not limited to, the following: (a) branched and / or chain extended dimethylhydrogensiloxy terminated polydimethylsiloxanes; (b) dimethylhydrogensiloxy-terminated dimethylsiloxane-methylhydrogensiloxane copolymer; (c)(CH3)2HSiO 1 / 2 Unit: (CH3)3SiO 1 / 2 Units, and SiO 4 / 2 copolymers and / or silicone resins consisting of units; (d)(CH3)2HSiO 1 / 2 Units and SiO 4 / 2 copolymers and / or silicone resins consisting of units; (e)(CH3)2HSiO 1 / 2 Units, SiO 4 / 2 Units and (C6H5)3SiO 1 / 2 Copolymers of units and / or silicone resins, and alternatives thereof where the methyl is replaced by a phenyl group or other alkyl group.

[0027] Others include tetrakis(dimethylsiloxy)silane, hydride terminated, polyphenylmethylsiloxane hydride terminated, polyphenyl-(dimethylhydrosiloxy)siloxane, or phenyltris(dimethylsiloxy)silane, etc. Alternatively, the crosslinker, component B, may be a filler, such as silica, that has been treated with one of the above.

[0028] Polyorganosiloxanes containing at least two or three -Si-H groups per molecule (B) are typically added in an amount such that the molar ratio of silicon-bonded hydrogen atoms in component (B) to that of all unsaturated groups in the composition is 0.5:1 to 20:1, alternatively 0.5:1 to 5:1, alternatively 0.6:1 to 3:1. If this ratio is less than 0.5:1, a sufficiently cured composition is not obtained. If this ratio is greater than 20:1, the hardness of the cured composition tends to increase when heated.

[0029] The silicon-bonded hydrogen (Si-H) content of component (B) is determined using quantitative infrared analysis according to ASTM E168. In the present invention, the ratio of silicon-bonded hydrogen to alkenyl (vinyl) and / or alkynyl is important when relying on a hydrosilylation cure process. Generally, this is determined by calculating the total weight percent of alkenyl groups in the composition, e.g., vinyl [V], and the total weight percent of silicon-bonded hydrogen [H] in the composition, where the molecular weight of hydrogen is 1 and the molecular weight of vinyl is 27, resulting in a molar ratio of silicon-bonded hydrogen to vinyl of 27 [H] / [V].

[0030] The molecular weight of this component is not particularly limited, but the viscosity is typically 15-50,000 mPa.s at 25° C., depending on the viscosity below 1000 MPa.s, using either a Brookfield™ rotational viscometer with spindle LV-4 (designed for viscosities in the range of 1,000-2,000,000 MPa.s), or a Brookfield™ rotational viscometer with spindle LV-1 (designed for viscosities in the range of 15-20,000 MPa.s), and the speed, i.e., shear rate, is selected according to the polymer viscosity, e.g., from 0.005 s -1 From 1s -1 (0.3~60rpm) according to (in this case 1s -1 is preferred), and adapt it.

[0031] Typically, depending on the number of unsaturated groups in component (A) and the number of Si-H groups in component (B), component (B) will be present in an amount from 0.1 to 20% by weight of the total composition, alternatively from 0.5 to 20% by weight of the total composition, alternatively from 0.5 to 10% by weight of the total composition, or alternatively from 0.5% to 5% by weight of the total composition.

[0032] Component (C) is at least one hydrosilylation (addition) curing catalyst. Usually selected from catalysts of the platinum metal group (platinum, ruthenium, osmium, rhodium, iridium, and palladium) or one or more compounds of such metals. Platinum and rhodium compounds are preferred due to the high activity level of these catalysts in hydrosilylation reactions. Component (C) catalyzes the reaction between the unsaturated group (e.g., alkenyl group) of component (A) and the Si-H group of component (B), resulting in a crosslinked network when the hydrosilylation curable silicone composition is cured into its corresponding elastomer.

[0033] The catalyst (C) may be a platinum group metal, a platinum group metal deposited on a support such as activated carbon, a metal oxide such as aluminum oxide or silicon dioxide, silica gel or powdered charcoal, or a compound or complex of a platinum group metal.

[0034] Examples of preferred hydrosilylation catalysts (C) are platinum-based catalysts, such as platinum black, platinum oxide (Adams' catalyst), platinum on various solid supports, chloroplatinic acid, alcoholic solutions of chloroplatinic acid, and complexes of chloroplatinic acid with ethylenically unsaturated compounds such as olefins and organosiloxanes containing ethylenically unsaturated silicon-bonded hydrocarbon groups. Usable soluble platinum compounds include, for example, platinum-olefin complexes of the formula (PtCl2(olefin)2 and H(PtCl3.olefin), in which preference is given in this context to the use of alkenes having 2 to 8 carbon atoms, such as ethylene, propylene, the isomers of butene and the isomers of octene, or cycloalkanes having 5 to 7 carbon atoms, such as cyclopentene, cyclohexene, and cycloheptene. Other soluble platinum catalysts are, for example, those of the formula (PtCl2C3H 6) Platinum-cyclopropane complexes of 2, which are reaction products of hexachloroplatinic acid with alcohols, ethers, and aldehydes or mixtures thereof, or with methylvinylcyclotetrasiloxane in the presence of sodium bicarbonate in an ethanolic solution. Platinum catalysts with phosphorus, sulfur, and amine ligands, e.g., (Ph3P)2PtCl2, and complexes of platinum with vinylsiloxanes, such as sym-divinyltetramethyldisiloxane, may also be used.

[0035] Therefore, specific examples of suitable platinum-based catalysts include: (i) Complexes of chloroplatinic acid with organosiloxanes containing ethylenically unsaturated hydrocarbon groups, as described in U.S. Pat. No. 3,419,593; (ii) chloroplatinic acid, either in its hexahydrate or anhydrous form; (iii) a platinum-containing catalyst obtained by a process comprising reacting chloroplatinic acid with an aliphatically unsaturated organosilicon compound, such as divinyltetramethyldisiloxane; (iv) alkene-platinum-silyl complexes as described in U.S. Pat. No. 6,605,734, such as (COD)Pt(SiMeCl2)2, where "COD" is 1,5-cyclooctadiene, and / or (v) Karstedt's catalysts, which are complexes of platinum and divinyltetramethyldisiloxane, typically containing about 1% by weight of platinum in a solvent, such as toluene, are described in U.S. Patents 3,715,334 and 3,814,730.

[0036] The hydrosilylation catalyst (C) of the hydrosilylation-curable silicone composition is present in the overall composition in a catalytic amount, i.e., an amount or quantity sufficient to catalyze the addition / hydrosilylation reaction and cure the composition into an elastomeric material under desired conditions. Various levels of hydrosilylation catalyst (C) may be used to adjust the reaction rate and cure rate. The catalytic amount of hydrosilylation catalyst (C) is generally 0.01 ppm to 10,000 ppm, alternatively 0.01 to 5000 ppm, alternatively 0.01 to 3,000 ppm, alternatively 0.01 to 1,000 ppm, by weight of platinum group metal per million parts (ppm) based on the weight of the composition. In certain embodiments, the catalytic amount of catalyst may range from 0.01 to 1,000 ppm, alternatively 0.01 to 750 ppm, alternatively 0.01 to 500 ppm, alternatively 0.01 to 100 ppm of metal based on the weight of the composition. The ranges may relate to just the metal content in the catalyst, or to the entire catalyst (including its ligands), as specified, but typically these ranges relate to just the metal content in the catalyst. The catalyst may be added as a single species or as a mixture of two or more different species. Typically, depending on the form / concentration in which the catalyst package is provided, the amount of catalyst present is in the range of 0.001-3.0% by weight of the composition.

[0037] Component (D) is a hydrosilylation cure inhibitor consisting of or including one or more multiacrylate compounds containing at least three acrylate groups per molecule. The multiacrylates having at least three acrylate groups per molecule of component (D) are provided herein to function as hydrosilylation cure inhibitors to inhibit and / or slow the hydrosilylation (addition) reaction process at room temperature to improve process stability. The one or more multiacrylate compounds containing at least three acrylate groups per molecule may contain 3 to 10 acrylate groups per molecule, such as triacrylates, tetraacrylates, pentaacrylates and hexaacrylates, or 3 to 6 acrylate groups per molecule, or 3 to 5 acrylate groups per molecule. For example, the one or more multiacrylate compounds containing at least three acrylate groups may include:

[0038] [ka]

[0039] Depending on the type of inhibitor present in the composition, inhibitor concentrations as low as one mole of inhibitor per mole of catalyst metal may provide sufficient retardation of the cure rate in some cases. For example, in the case of component D herein, inhibitor concentrations of up to 2000 moles of inhibitor per mole of catalyst metal or more may be required. The optimum concentration for a given inhibitor in a given composition is readily determined by routine experimentation. For example, the hydrosilylation cure inhibitor(s) present in component D alone or in combination with one or more other hydrosilylation cure inhibitors are typically present at a total hydrosilylation cure inhibitor content of 0.0125-10% by weight of the composition, alternatively 0.0125-5% by weight of the composition, alternatively 0.025-3% by weight of the composition.

[0040] Depending on the intended use of the curable silicone elastomer composition, optional additives may be present in the composition. Examples include one or more standard hydrosilylation cure inhibitors, fillers, adhesion promoters, mold release agents, adhesion catalysts, antioxidants, and / or pigments and / or colorants. Other additives may include conductive fillers, thermally conductive fillers, pot life extension agents, flame retardants, lubricants, mold release agents, UV light stabilizers, germicides, wetting agents, heat stabilizers, compression set additives, and plasticizers.

[0041] The multiacrylate having at least three acrylate groups per molecule of component (D) does not have to be the only hydrosilylation cure inhibitor.Other standard hydrosilylation cure inhibitors may also be present in the compositions described herein.These may include hydrazines, triazoles, phosphines, mercaptans, organic nitrogen compounds, acetylene alcohols, silylated acetylene alcohols, maleates, fumarates, ethylenically or aromatically unsaturated amides, ethylenically unsaturated isocyanates, olefinic siloxanes, unsaturated hydrocarbon monoesters and diesters, conjugated ene-ynes, hydroperoxides, nitriles, diaziridines, and alkenyl-substituted siloxanes such as cyclic methylvinylsiloxanes as described in US Pat. No. 3,989,667 may be used.

[0042] One well-known class of hydrosilylation cure inhibitors includes the acetylenic compounds disclosed in U.S. Patent No. 3,445,420. Acetylenic alcohols such as 2-methyl-3-butyn-2-ol are a preferred class of hydrosilylation cure inhibitors that suppress the activity of platinum-containing catalysts at 25° C. Typically, compositions containing these hydrosilylation cure inhibitors must be heated to temperatures of 70° C. or greater in order to cure at a practical rate.

[0043] Examples of acetylenic alcohols and their derivatives include 1-ethynyl-1-cyclohexanol (ETCH), 2-methyl-3-butyn-2-ol, 3-butyn-1-ol, 3-butyn-2-ol, propargyl alcohol, 1-phenyl-2-propyn-1-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclopentanol, 3-methyl-1-penten-4-yn-3-ol, and mixtures thereof. Derivatives of acetylenic alcohols may include those compounds having at least one silicon atom.

[0044] When a standard hydrosilylation cure inhibitor is present in addition to the multiacrylate having at least three acrylate groups per molecule of component (D) herein, the total amount of hydrosilylation cure inhibitor present remains from 0.0125 to 10 weight percent of the composition, alternatively from 0.0125 to 5 weight percent, alternatively from 0.025 to 3 weight percent, based on the weight of the composition.

[0045] The composition may also contain one or more reinforcing fillers, preferably finely divided, one or more non-reinforcing fillers, or mixtures thereof.

[0046] When present, the reinforcing fillers may be exemplified by finely divided fumed silica and / or finely divided precipitated silica and / or a suitable silicone resin.

[0047] Precipitated silica, fumed silica and / or colloidal silica are generally at least 50m 2 / g (BET method according to ISO 9277:2010). 2 / g (BET method according to ISO9277:2010), or 50-400m 2 Use fillers with a surface area of ​​0.1 μm / g (BET method according to ISO 9277:2010). All these types of silica are commercially available.

[0048] Typically, such reinforcing fillers are hydrophilic in nature (e.g., untreated silica fillers) and therefore are usually treated with a treating agent to render them hydrophobic. These surface-modified reinforcing fillers do not agglomerate and can be homogeneously incorporated into the polyorganosiloxane of component (A) because the surface treatment renders the filler readily wetted by component (A).

[0049] The reinforcing fillers may be surface treated with any low molecular weight organosilicon compound disclosed in the art that can be applied to facilitate handling of the filler, obtain a homogeneous mixture with other components, and prevent creping of the organosiloxane composition during processing, such as organosilanes, polydiorganosiloxanes, or organosilazanes, such as hexaalkyldisilazanes, short chain siloxane diols, that render the filler(s) hydrophobic, thus making them easier to handle and obtain a homogeneous mixture with other components. Specific examples include silanol-terminated trifluoropropylmethylsiloxane, silanol-terminated vinylmethyl (ViMe) siloxane, silanol-terminated methylphenyl (MePh) siloxane, liquid hydroxyldimethyl-terminated polydiorganosiloxanes containing an average of 2 to 20 diorganosiloxane repeat units in each molecule, hydroxyldimethyl-terminated phenylmethylsiloxane, hexaorganodisiloxanes such as hexamethyldisiloxane, divinyltetramethyldisiloxane, and hexamethyldisilazane (HMD Z), hexaorganodisilazanes such as divinyltetramethyldisilazane and tetramethyldi(trifluoropropyl)disilazane, hydroxyldimethyl-terminated polydimethylmethylvinylsiloxane, octamethylcyclotetrasiloxane, and silanes including, but not limited to, methyltrimethoxysilane, dimethyldimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, chlorotrimethylsilane, dichlorodimethylsilane, trichloromethylsilane.

[0050] A small amount of water may be added along with the silica treating agent as a processing aid.

[0051] The surface treatment may be carried out prior to the introduction of the filler into the composition, or may be carried out in situ during the preparation of the base material which typically comprises substantially the polyorganosiloxane component (A) and the filler.

[0052] When present, the reinforcing filler is present in an amount from 2.5 to 40 wt% of the composition, alternatively from 5.0 to 35 wt% of the composition, alternatively from 7.5 to 35 wt% of the composition.

[0053] Non-reinforcing fillers may alternatively or additionally be included in the compositions herein. These may include, for example, crushed quartz, diatomaceous earth, barium sulfate, iron oxide, titanium dioxide and carbon black, talc, wollastonite, aluminite, calcium sulfate (anhydrite), gypsum, calcium sulfate, powdered calcium carbonate, magnesium carbonate, clays such as kaolin, aluminum trihydroxide, magnesium hydroxide (hydrotalcite), graphite, copper carbonates such as malachite, nickel carbonates such as zarachite, barium carbonates such as witherite and / or strontium carbonates such as strontianite.

[0054] Other non-reinforcing fillers may include aluminum oxide, olivine family, garnet family, aluminosilicates, cyclic aluminosilicates, chain aluminosilicates, and silicates from the group consisting of layered aluminosilicates. The olivine family includes silicate minerals such as, but not limited to, forsterite and Mg2SiO4. The garnet family includes red garnet and Mg3Al2Si3O 12 , green garnet, Ca2Al2Si3O 12 and powdered silicate minerals such as, but not limited to, sillimanite, Al2SiO5, mullite, 3Al2O3.2SiO2, kyanite, and Al2SiO5. Cyclic silicates may be utilized as non-reinforcing fillers, such as cordierite and Al3(Mg,Fe)2[Si4AlO 18The chain silicate family includes, but is not limited to, powdered silicate minerals such as wollastonite and Ca[SiO3]. Layered silicates may alternatively or additionally be used as non-reinforcing fillers, suitable groups being silicate minerals such as mica and K2AI. 14 [Si6Al2O 20 ](OH)4, pyrophyllite, and Al4[SiO 20 ](OH)4, talc, and Mg6[SiO 20 ](OH)4, serpentine, e.g. asbestos, kaolinite, Al4[Si4O 10

[0023] (OH)8 and silicate minerals such as vermiculite. In one alternative, the filler is selected from one or more of fumed silica, precipitated silica, calcium carbonate, talc, mica, quartz, and aluminum oxide.

[0055] The hydrosilylation curable silicone composition described herein may also include an adhesion promoter. However, it is noted that component D, the multiacrylate, may further function as an adhesion promoter, and thus the use of component D as a hydrosilylation cure inhibitor may have the advantage of eliminating the need for an additional adhesion promoter. However, if necessary, an additional adhesion promoter may be utilized in the composition. If present, the additional adhesion promoter may include one or more monoacrylates, diacrylates, or methacrylates. Examples include C acrylates such as hexanediol diacrylate, heptanediol diacrylate, octanediol diacrylate, nonanediol diacrylate, and / or undecanediol diacrylate. 4~20Diacrylates may be included, such as alkanediol diacrylates. Examples of monoacrylates include methacryl or acryl-containing alkoxysilanes, such as methacryloxymethyl-trimethoxysilane, 3-methacryloxypropyl-trimethoxysilane, 3-methacryloxypropyl-methyldimethoxysilane, 3-methacryloxypropyl-dimethylmethoxysilane, 3-methacryloxypropyl-triethoxysilane, 3-methacryloxypropyl-methyldiethoxysilane, 3-methacryloxyisobutyl-trimethoxysilane, or similar methacryloxy-substituted alkoxysilanes, and 3-acryloxypropyl-trimethoxysilane, 3-acryloxypropyl-methyldimethoxysilane, 3-acryloxypropyl-dimethyl-methoxysilane, 3-acryloxypropyl-triethoxysilane, or similar acryloxy-substituted alkyl-containing alkoxysilanes. In one embodiment, the optional additional adhesion promoter, if present, does not include one or more monoacrylates, diacrylates, or methacrylates.

[0056] Examples of epoxy-containing alkoxysilanes that may be used as adhesion promoters may include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 4-glycidoxybutyltrimethoxysilane, 5,6-epoxyhexyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, or 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane.

[0057] Adhesion catalysts, i.e., condensation catalysts used to activate and / or accelerate the reaction of the adhesion promoters described above, may also be utilized. Such condensation catalysts may be selected from organometallic catalysts including titanates (e.g., tetrapropoxytitanate), zirconates, organoaluminum chelates, titanium chelates, and / or zirconium chelates.

[0058] For example, titanate- and zirconate-based catalysts can be represented by the general formula Ti[OR 5 ]4 or Zr[OR 5 ]4, wherein each R 5 R may be the same or different and represent a monovalent, primary, secondary, or tertiary aliphatic hydrocarbon group, which may be linear or branched, having 1 to 20 carbon atoms, alternatively 1 to 10 carbon atoms. Optionally, the titanate or zirconate may contain partially unsaturated groups. 5 Preferred examples of R include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, tertiary butyl, and branched secondary alkyl groups, such as 2,4-dimethyl-3-pentyl. 5 is the same, preferably, R 5 is an isopropyl group, a branched secondary alkyl group or a tertiary alkyl group, in particular a tertiary butyl group. Specific examples include, but are not limited to, zirconium tetrapropylate and zirconium tetrabutylate, tetra-isopropyl zirconate, zirconium(IV) tetraacetylacetonate (sometimes referred to as zirconium AcAc), zirconium(IV) hexafluoroacetylacetonate, zirconium(IV) trifluoroacetylacetonate, tetrakis(ethyltrifluoroacetylacetonate)zirconium, tetrakis(2,2,6,6-tetramethyl-heptanethionate)zirconium, zirconium(IV) dibutoxybis(ethylacetonate), zirconium tributoxyacetylacetate, zirconium butoxyacetylacetonate bisethylacetoacetate, diisopropoxybis(2,2,6,6-tetramethyl-heptanethionate)zirconium, or similar zirconium complexes having β-diketones used as ligands, including their alkyl- and fluorine-substituted forms. Titanate equivalents of the above zirconates are also included.

[0059] Suitable aluminum-based condensation catalysts include Al(OC3H7)3, l(OC3H7)2(C3COCH2COC 12 H25 ), Al(OC3H7)2(OCOCH3), and Al(OC3H7)2(OCOC 12 H 25 ) may be mentioned.

[0060] If deemed necessary and / or beneficial, the adhesion promoter may also include other ingredients such as other silane coupling agents, organic compounds containing two or more acrylate groups and / or reactive siloxanes.

[0061] Examples of adhesion promoters include silane coupling agents such as methyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, and 1,6-bis(trimethylsilyl)hexane, 3-methacryloxypropyltrimethoxysilane, and / or glycidoxypropyltrimethoxysilane.

[0062] The one or more adhesion promoter(s) are typically present in the composition in a total amount of from about 0.1 to 6% by weight of the composition, alternatively from 0.1 to 4% by weight of the composition.

[0063] Examples of conductive fillers include metal particles, metal oxide particles, metal coated metal particles (such as silver plated nickel), metal coated non-metal core particles (such as silver coated talc, or mica, or quartz), and combinations thereof. The metal particles may be in the form of powders, flakes, or filaments, and may be mixtures or derivatives thereof.

[0064] Examples of thermally conductive fillers include boron nitride, alumina, metal oxides (such as zinc oxide, iron oxide, magnesium oxide, and aluminum oxide), graphite, diamond, and mixtures or derivatives thereof.

[0065] Examples of pigments include titanium dioxide, chromium oxide, bismuth vanadium oxide, iron oxide, and mixtures thereof.

[0066] Examples of colorants or stains that may be utilized in the hydrosilylation curable silicone composition include pigments, vat dyes, reactive dyes, acid dyes, chrome dyes, disperse dyes, cationic dyes, and mixtures thereof. The dual moisture curable organopolysiloxane composition described herein may further include one or more pigments and / or colorants that may be added as needed. The pigments and / or colorants may be colored, white, black, metallic effect, and luminescent, such as fluorescent and phosphorescent. The pigments are utilized as needed to color the composition. Any suitable pigment may be utilized as long as it is compatible with the compositions herein. In the dual moisture curable organopolysiloxane composition, pigments and / or colored (non-white) fillers, such as carbon black, may be used in the catalyst package to color the end sealant product.

[0067] Suitable white pigments and / or colorants include titanium dioxide, zinc oxide, lead oxide, zinc sulfide, lithopone, zirconium oxide, and antimony oxide.

[0068] Suitable non-white inorganic pigments and / or colorants include, but are not limited to, iron oxide pigments such as goethite, lepidocrite, hematite, maghemite, and magnetite, black, yellow, brown, and red iron oxides, blue iron pigments, chromium oxide pigments, cadmium pigments such as cadmium yellow, cadmium red, cadmium cinnabar, bismuth pigments such as bismuth vanadate, bismuth molybdate vanadate, mixed metal oxide pigments such as cobalt titanate green, chromate and molybdate pigments such as chrome yellow, molybdate red, and molybdate orange, ultramarine pigments, cobalt oxide pigments, nickel antimony titanate, lead chromium, carbon black, lamp black, and metallic effect pigments such as aluminum, copper, copper oxide, bronze, stainless steel, nickel, zinc, and brass.

[0069] Suitable organic non-white pigments and / or colorants include phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green, monoarylide yellow, diarylide yellow, benzimidazolone yellow, heterocyclic yellow, DAN orange, quinacridone pigments such as quinacridone magenta and quinacridone violet, organic reds including metallized and non-metallized azo reds and other azo pigments, monoazo pigments, diazo pigments, azo pigment lakes, β-naphthol pigments, naphthol AS pigments, benzimidazolone pigments, diazo condensed pigments, 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 diketopyrrolopyrrole pigments.

[0070] Typically, the pigments and / or colorants, if particulate, have an average particle size in the range of 10 nm to 50 μm, preferably in the range of 40 nm to 2 μm. When present, the pigments and / or colorants are present in a range of from 2 wt % of the catalyst package composition, alternatively from 3 wt %, alternatively from 5 wt % to 20 wt %, alternatively up to 15 wt % of the catalyst package composition, alternatively up to 10 wt % of the catalyst package composition.

[0071] In a preferred embodiment of the present invention, the pigment and dye are used in the form of a pigment master batch constituted by dispersing them in the component (a) at a ratio of 25:75 to 70:30.

[0072] Further additives include silicone fluids such as trimethylsilyl or OH terminated siloxanes. Such trimethylsiloxy or OH terminated polydimethylsiloxanes typically have a viscosity of less than (<) 150 mPa.s at 25° C. Such silicone fluids, when present, may be present in the curable silicone elastomer composition in an amount ranging from 0.1 to 5 wt %, based on the total weight of the composition.

[0073] The hydrosilylation-curable silicone rubber composition may include the following: Component (A), one or more organopolysiloxanes containing at least two alkenyl groups per molecule, having a viscosity in the range of 1000 mPa.s to 200,000 mPa.s at 25° C., in an amount of 5 to 95% by weight based on the total weight of the composition, alternatively 35 to 85% by weight based on the total weight of the composition, alternatively 40 to 80% by weight based on the total weight of the composition, and further alternatively 50 to 80% by weight based on the total weight of the composition; Component (B), a polyorganosiloxane containing at least two or three silicon-bonded hydrogen atoms per molecule, in an amount of 0.1 to 40 weight percent of the total composition, alternatively 0.5 to 20 weight percent of the total composition, alternatively 0.5 to 10 weight percent of the total composition, and further alternatively 1 to 5 weight percent of the total composition; Component (C) of at least one hydrosilylation catalyst in an amount of 0.01 to 10% by weight of the total composition, alternatively 0.01 to 5% by weight of the total composition, and further alternatively 0.05 to 2% by weight of the total composition; Component (D), a hydrosilylation cure inhibitor consisting of or comprising one or more multiacrylate compounds containing at least three acrylate groups per molecule, is typically present in an amount of 0.0125 to 10% by weight of the composition, alternatively 0.0125 to 5% by weight of the composition, alternatively 0.025 to 3% by weight of the composition. The total weight percent of any composition herein is 100% by weight.

[0074] The hydrosilylation-curable silicone compositions described above are typically stored in two or more parts prior to use, but may be provided as one-part compositions and appropriately prepared if desired. When a binary composition, i.e., having part (A) and part (B), is used, Part (A) typically contains, in addition to the polyorganosiloxane (A) and filler, a catalyst (C), if present; Part (B) typically comprises the crosslinker and polyorganosiloxane (A) of component (B), and, if present, a filler.

[0075] The utilization of the multi-component composition prior to use is designed to store the catalyst (C) separately from the crosslinker (B) to prevent premature curing during storage. The multiacrylate compounds having at least three acrylate groups per molecule of component D described herein may be incorporated into either part A or part B, unlike many conventional hydrosilylation cure inhibitors, such as alkynols, which must generally be kept in the composition of part B to avoid aggregation and precipitation during storage and thus separation of the alkynol / Pt complex with the catalyst.

[0076] Optional additives may be present in either part (A) or part (B), or both, provided that their presence is not in any way detrimental to the other ingredients present in each part.

[0077] The components of the hydrosilylation-curable silicone composition of the present invention may be mixed homogeneously using any suitable mixing means, such as a kneader mixer, a Z-blade mixer, a two-roll mill (open mill), a three-roll mill, a Haake® Rheomix OS Lab mixer, a screw extruder or a twin-screw extruder. Other suitable mixers include those sold under the brand name SpeedMixer® by Hauschild & Co KG (Germany), for example DC150.1FV, DAC400FVZ and DAC600FVZ may alternatively be used.

[0078] The curable hydrosilylation-curable silicone composition may be processed (or cured) by injection molding, press molding, extrusion molding, transfer molding, press vulcanization, or calendaring.

[0079] The hydrosilylation-curable silicone composition as described herein above may be applied to the surface of a substrate by any suitable means, such as rolling, spreading, 3D printing, etc., and cured as described above. When using a 3D printing method. A typical method for forming a three-dimensional (3D) article may include multiple steps. For example, the method may include (i) printing a first hydrosilylation-curable silicone composition as described herein by a 3D printer to form a layer. The method may further include (ii) heating the layer to form an at least partially cured layer. However, the method may include (iii) printing a second hydrosilylation-curable silicone composition as described herein by a 3D printer on the at least partially cured layer to form a subsequent layer. The method may further include (iv) heating the subsequent layer to form an at least partially cured subsequent layer. Optionally, steps iii) and iv) may be repeated for any additional layers using independently selected curable silicone compositions to form a 3D article.

[0080] After application of the hydrosilylation-curable silicone composition onto a substrate, the composition is cured at a cure temperature ranging from 80° C. to 250° C. Such temperatures are generally determined by the materials involved.

[0081] The hydrosilylation curable silicone composition provided herein may be used in the preparation of a wide variety of products in various industries, including but not limited to automotive, medical, consumer and industrial, electronic applications.In automotive applications, it may include housings with silicone seals or gaskets, plugs and connectors, components of various sensors, membranes, bulkheads, climate ventilation components, etc.Electronic applications may include mobile phone cover seals, mobile phone accessories, precision electronic equipment, electrical switches and switch covers, watches and wristbands, wearable appliances, such as face masks, wearable electronic devices, etc.

[0082] The hydrosilylation-curable silicone compositions provided herein may be used in parts of mobile phones, mobile communication devices, game consoles, watches, image receivers, DVD devices, MD devices, CD devices, and other precision electronic devices, microwave ovens, refrigerators, electric rice cookers, televisions, flat-screen displays of LCD televisions and plasma televisions, various home appliances, copiers, printers, facsimile machines, and other office automation (OA) equipment, connector seals, spark plug caps, components of various sensors, and other automobile components. EXAMPLES

[0083] The following examples are provided to demonstrate the functionality of the aforementioned multiacrylates as hydrosilylation cure inhibitors. The viscosity values ​​of the different components of the compositions used were calculated for viscosities below 1000 MPa.s, i.e., at shear rates of 1 s -1 (60 rpm) using either a Brookfield™ rotational viscometer with spindle LV-4 (designed for viscosities in the range of 1,000 to 2,000,000 MPa.s) or a Brookfield™ rotational viscometer with spindle LV-1 (designed for viscosities in the range of 15 to 20,000 MPa.s) unless otherwise indicated. All viscosities were measured at 25°C unless otherwise indicated.

[0084] In the following examples, Masterbatch MB1 is a mixture of MB1, a 70.8 wt. % dimethylvinylsiloxy-terminated polydimethylsiloxane having a viscosity of about 53,000 MPa.s at 25°C, and about 300 ml 2 The silica contained 22.4 wt. % MB1, a fumed silica filler having a surface area of ​​1 / g, and the remainder was a hydrophobizing treatment. The silica was hydrophobized and contained no vinyl functionality. Masterbatch MB2 is a mixture of MB2, a 66.6 wt. % dimethylvinylsiloxy-terminated polydimethylsiloxane having a viscosity of about 55,000 MPa.s at 25°C, and about 300 ml 2% of MB2, a fumed silica filler having a surface area of ​​0.178 mmol / g, and the remainder was a hydrophobizing treatment. The silica was hydrophobized and had a vinyl functionalization of about 0.178 mmol / g. Polymer A1 was a vinyldimethyl terminated polydimethylsiloxane having a viscosity of 53,000 mPa.s at 25°C. Polymer A2 was a vinyl-terminated poly(dimethylsiloxane-co-methylvinylsiloxane) having a viscosity of 370 mPa.s at 25°C. Crosslinker B1 is HMe2SiO with 0.97 wt% H as SiH and a viscosity of 22 mPa.s. 0.5 Blockade M H Q resin. This was the M(H) crosslinker. Crosslinker B2 is MeSiO with 0.70 wt% H as SiH and a viscosity of ∼48 mPa.s at 25 °C. 0.5 It was a terminal poly(dimethyl-co-methylhydrogen)siloxane, which is the D(H) crosslinker. The OH-terminated PDMS was a hydroxydimethyl-terminated polydimethylsiloxane with a viscosity of about 21 MPa.s. The tetraacrylate used was di(trimethylolpropane)tetraacrylate (described above). The triacrylate used was trimethylolpropane triacrylate (above). The diacrylate used was

[0085] [ka]

[0086] The compositions used were prepared in two parts, and then the two parts were mixed together to provide the final hydrosilylation-curable silicone composition. Table 1a provides examples of the Part A and Part B compositions of Example 1, Example 5, and C.5. Subsequent compositions provided in Table 1b, etc., are the combined Part A+Part B compositions after mixing.

[0087] [Table 1]

[0088] A series of examples were prepared using the Part A and Part B compositions similar to those shown in Table 1a. The Part A and Part B compositions were prepared by first mixing the two masterbatches and then adding the remaining ingredients from each part. Once the Part A and Part B compositions were prepared, they could be mixed together if desired. The compositions provided in the table below are the combined Part A and Part B compositions after mixing.

[0089] [Table 2]

[0090] The examples identified in Table 1b were then tested to provide details of the cure parameters Tc2, Tc60, Tc90, i.e., the time taken to reach 2%, 60% and 90% cure. These tests were carried out in accordance with ASTM D5289-19a on an Alpha Technologies Premier MDR Moving Die Rheometer. Measurements were taken at 120°C for a 10 minute cure period.

[0091] For each example, after storage at 25° C. for 1, 24, 48, and 72 hours, the rheology was measured using a TA Instruments plate-plate AR2000EX rheometer with a cell gap of 500 micrometers and a 10 s -1 Viscosity measurements were performed according to DIN 53018 to report the effect of the presence of the hydrosilylation cure inhibitor(s) on the cure retardation of the composition at a shear rate of 100 rpm. The results are provided in Table 1c below.

[0092] [Table 3]

[0093] Example 1 (Example 1) clearly shows that the multiacrylate clearly functions as a hydrosilylation cure inhibitor. No previously recognized hydrosilylation cure inhibitor is present in the composition of Example 1, and its ability to retard cure is still evident even after more than (>) 48 hours. Thus, clearly shows that the multiacrylate can be present as the only hydrosilylation cure inhibitor.

[0094] The above examples are compared with a series of comparative examples C.1 to C.9, the compositions of which are given in Tables 2a and 2b below.

[0095] [Table 4]

[0096] In Table 2b, the dimethacrylate used was hexanediol-dimethacrylate, having the following structure:

[0097] [ka] The trimethacrylate used was trimethylolpropane trimethacrylate, which has the following structure:

[0098] [ka]

[0099] [Table 5]

[0100] The aforementioned comparative compositions were then also evaluated for Tc2, Tc60, Tc90, and viscosity change over time using the same test methods described above, with the results shown in Tables 2c and 2d.

[0101] [Table 6]

[0102] This can be seen from Comparative Examples C.1, C2 and C3 that the addition of acrylates to a standard hydrosilylation cured silicone rubber composition using a standard D(H) crosslinker slows down the curing process and shortens the time before gelation. This problem is overcome when using a multi-acrylate hydrosilylation cure inhibitor, for example in Example 1.

[0103] When comparing Example 1 with C6, it can be seen that the multiacrylate functions as a hydrosilylation cure inhibitor only for the M(H) crosslinker. For example, using C.6, the composition is seen to cure at room temperature for only 24 hours.

[0104] Example 2 shows a viscosity of 1317 Pa.s after 3 days, which is a significant improvement compared to, for example, C7 (diacrylate) using the same molar amount of acrylate, and is already gelled after 24 hours despite having an additional ETCH as a co-inhibitor and also showing a slower cure.

[0105] Examples 2, 3 and 7 (to Example 2, Example 3 and Example 7) show that the reduction in the rate of viscosity increase over time when using a multi-acrylate hydrosilylation cure inhibitor as previously described is only evident when combined with an M(H) type crosslinker, as can be seen in Example 3 (M(H) crosslinker and tetraacrylate) compared to C.3 (D(H) crosslinker and tetraacrylate). Example 3 cures faster and has a slower rate of viscosity increase over time, while C.3 has a relatively faster viscosity increase over time.

[0106] Example 4 shows that the use of higher multiacrylate loadings can be utilized to increase adhesion. Comparing Example 4 with C.5, it can be seen that the use of diacrylates at equimolar acryloxy concentrations results in similar cure rates at 120° C., which is perhaps only to be expected.

[0107] [Table 7]

[0108] It can be seen that compositions C7-9 were not retarded, unlike those using the multi-acrylate hydrosilylation cure inhibitors described herein, clearly indicating that disilates as well as multi-methacrylates do not provide the same retarding effect on the hydrosilylation process. The invention as originally claimed in the present application is set forth below. [1] A hydrosilylation-curable silicone composition comprising: (A) one or more polyorganosiloxanes containing at least two unsaturated groups per molecule, the unsaturated groups being selected from alkenyl and alkynyl groups, and having a viscosity in the range of 1000 mPa.s to 200,000 mPa.s at 25°C; (B) a polyorganosiloxane containing at least two, alternatively at least three, terminal silicon-bonded hydrogen groups; (C) at least one hydrosilylation catalyst; (D) a hydrosilylation cure inhibitor consisting of or including a multiacrylate compound having at least three acrylate groups per molecule. [2] The hydrosilylation-curable silicone composition according to [1], wherein the multiacrylate contains 3 to 10 acrylate groups per molecule. [3] The hydrosilylation-curable silicone composition according to any one of [1] to [2], wherein the multiacrylate is selected from a triacrylate, a tetraacrylate, a pentaacrylate, a hexaacrylate, or a mixture thereof. [4] The hydrosilylation-curable silicone composition according to any one of [1] to [3], wherein the multiacrylate is selected from pentaerythritol tetraacrylate, dipentaerythritol penta- / hexa-acrylate, pentaerythritol triacrylate, di(trimethylolpropane)tetraacrylate, trimethylolpropane triacrylate, or a mixture thereof. [5] The hydrosilylation-curable silicone composition according to any one of [1] to [4], wherein component (D) further contains one or more acetylene alcohols selected from 1-ethynyl-1-cyclohexanol, 2-methyl-3-butyn-2-ol, 3-butyn-1-ol, 3-butyn-2-ol, propargyl alcohol, 1-phenyl-2-propyn-1-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclopentanol, 3-methyl-1-penten-4-yn-3-ol, and mixtures thereof. [6] The hydrosilylation-curable silicone composition according to any one of [1] to [5], further comprising one or more reinforcing fillers and / or non-reinforcing fillers. [7] The hydrosilylation-curable silicone composition according to any one of [1] to [6], further comprising one or more additives selected from adhesion promoters, release agents, adhesion catalysts, antioxidants, pigments, electrically conductive fillers, thermally conductive fillers, pot life extenders, flame retardants, lubricants, release agents, UV light stabilizers, germicides, wetting agents, heat stabilizers, compression set additives, and plasticizers, or mixtures thereof. [8] The hydrosilylation-curable silicone composition according to any of [1] to [7], wherein the hydrosilylation-curable silicone composition is stored prior to use in two portions, namely, portion (A) containing catalyst (C), polyorganosiloxane (A), and, if present, filler, and portion (B) containing component (B), the crosslinker, and polyorganosiloxane (A), and, if present, optionally filler, such that catalyst (C) and crosslinker (B) are stored separately. [9] The hydrosilylation-curable silicone composition of [8], wherein the multiacrylate compound having at least three acrylate groups per molecule of component D can be stored in Part A, Part B, or Part A and Part B.

[10] The hydrosilylation-curable silicone composition of [8] or [9], wherein component (D) further comprises one or more acetylenic alcohols selected from 1-ethynyl-1-cyclohexanol, 2-methyl-3-butyn-2-ol, 3-butyn-1-ol, 3-butyn-2-ol, propargyl alcohol, 1-phenyl-2-propyn-1-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclopentanol, 3-methyl-1-penten-4-yn-3-ol, and mixtures thereof, and the one or more acetylenic alcohols are stored in the composition of part B.

[11] A cured silicone material that is a cured product of the hydrosilylation-curable silicone composition according to any one of [1] to

[10] .

[12] Use of a multiacrylate compound having at least three acrylate groups per molecule as a hydrosilylation cure inhibitor in the composition according to any one of [1] to

[10] .

[13] Use of a multiacrylate compound having at least three acrylate groups per molecule according to

[12] as a hydrosilylation cure inhibitor and adhesion promoter in the composition according to any one of [1] to

[10] .

[14] A method for preparing a cured silicone material by mixing the components of the hydrosilylation-curable silicone composition of any of [1] to

[10] and curing the composition at a temperature between 80°C and 250°C.

[15] The cured silicone material is a three-dimensional (3D) article, and the method further comprises: (i) printing an amount of the hydrosilylation-curable silicone composition described in any one of [1] to

[10] to form a layer; (ii) heating the layer to form an at least partially cured layer; (iii) printing a second amount of the hydrosilylation-curable silicone composition according to any one of [1] to

[10] onto the at least partially cured layer with the 3D printer to form a subsequent layer; (iv) heating the subsequent layer to form an at least partially cured subsequent layer; and, optionally, (v) repeating steps iii) and iv) may be repeated to form a 3D article.

Claims

1. 1. A hydrosilylation-curable silicone composition comprising: (A) one or more polyorganosiloxanes containing at least two unsaturated groups per molecule, the unsaturated groups being selected from alkenyl and alkynyl groups, and having a viscosity in the range of 1000 mPa.s to 200,000 mPa.s at 25°C; (B) a polyorganosiloxane containing at least two, alternatively at least three, terminal silicon-bonded hydrogen groups; (C) at least one hydrosilylation catalyst; (D) a hydrosilylation cure inhibitor consisting of or including a multiacrylate compound having at least three acrylate groups per molecule; The multiacrylate compound is selected from pentaerythritol tetraacrylate, dipentaerythritol penta- / hexa-acrylate, pentaerythritol triacrylate, di(trimethylolpropane)tetraacrylate, trimethylolpropane triacrylate, or a mixture thereof; The hydrosilylation-curable silicone composition does not contain a cage-type silsesquioxane, Component (B) is HMe ２ SiO ０．５ Blockade M Ｈ Q resin, A hydrosilylation-curable silicone composition.

2. 2. The hydrosilylation-curable silicone composition of claim 1, wherein component (D) further comprises one or more acetylenic alcohols selected from 1-ethynyl-1-cyclohexanol, 2-methyl-3-butyn-2-ol, 3-butyn-1-ol, 3-butyn-2-ol, propargyl alcohol, 1-phenyl-2-propyn-1-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclopentanol, 3-methyl-1-penten-4-yn-3-ol, and mixtures thereof.

3. 3. The hydrosilylation-curable silicone composition of claim 1 or 2, further comprising one or more reinforcing and / or non-reinforcing fillers.

4. 4. The hydrosilylation-curable silicone composition of any one of claims 1 to 3, further comprising one or more additives selected from adhesion promoters, mold release agents, adhesion catalysts, antioxidants, pigments, electrically conductive fillers, thermally conductive fillers, pot life extenders, flame retardants, lubricants, mold release agents, UV light stabilizers, germicides, wetting agents, heat stabilizers, compression set additives, and plasticizers, or mixtures thereof.

5. 5. The hydrosilylation-curable silicone composition of claim 1, wherein the hydrosilylation-curable silicone composition is stored in two parts prior to use, namely, part (A) containing catalyst (C), polyorganosiloxane (A), and, if present, filler, and part (B) containing component (B), the crosslinker, and polyorganosiloxane (A), and, if present, optionally filler, such that catalyst (C) and crosslinker (B) are stored separately.

6. 6. The hydrosilylation-curable silicone composition of claim 5, wherein the multiacrylate compound having at least three acrylate groups per molecule of component D can be stored in part (A), part (B), or part (A) and part (B).

7. 7. The hydrosilylation-curable silicone composition of claim 5 or 6, wherein component (D) further comprises one or more acetylenic alcohols selected from 1-ethynyl-1-cyclohexanol, 2-methyl-3-butyn-2-ol, 3-butyn-1-ol, 3-butyn-2-ol, propargyl alcohol, 1-phenyl-2-propyn-1-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclopentanol, 3-methyl-1-penten-4-yn-3-ol, and mixtures thereof, wherein the one or more acetylenic alcohols are stored in the composition of part (B).

8. A cured silicone material that is the cured product of the hydrosilylation-curable silicone composition of any one of claims 1 to 7.

9. Use of a multiacrylate compound having at least three acrylate groups per molecule as a hydrosilylation cure inhibitor in a composition according to any one of claims 1 to 7, The multiacrylate compound is selected from pentaerythritol tetraacrylate, dipentaerythritol penta- / hexa-acrylate, pentaerythritol triacrylate, di(trimethylolpropane)tetraacrylate, trimethylolpropane triacrylate, or a mixture thereof; use.

10. 10. Use of a multiacrylate compound having at least three acrylate groups per molecule according to claim 9 as a hydrosilylation cure inhibitor and adhesion promoter in the composition according to any one of claims 1 to 7.

11. 8. A method for preparing a cured silicone material by mixing the components of the hydrosilylation-curable silicone composition of any one of claims 1 to 7 and curing the composition at a temperature between 80°C and 250°C.

12. the cured silicone material is a three-dimensional (3D) article, the method further comprising: (i) printing an amount of the hydrosilylation-curable silicone composition of any one of claims 1 to 7 to form a layer; (ii) heating the layer to form an at least partially cured layer; (iii) printing a second amount of the hydrosilylation-curable silicone composition of any one of claims 1 to 7 onto the at least partially cured layer with a 3D printer to form a subsequent layer; (iv) heating said subsequent layer to form an at least partially cured subsequent layer; and, optionally, 12. The method of claim 11, comprising: (v) repeating steps (iii) and (iv) may be repeated to form a 3D article.

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