Silicone elastomer composition

Abstract

The present disclosure relates to curable silicone elastomer compositions (hereinafter "curable silicone elastomer compositions") having enhanced adhesion properties to a variety of substrates. Elastomers prepared by curing the aforementioned compositions can be adhered to a variety of substrates to form a composite comprising the elastomer prepared from the curable silicone elastomer composition and the substrate. Methods for adhering the elastomer curable silicone elastomer compositions to substrates are also provided. An adhesion promoting component (D) is provided to enhance adhesion. The component (D) is a polyorganosiloxane having (i) at least one unsaturated group per molecule selected from the group consisting of alkenyl groups and alkynyl groups, and (ii) an anhydride functional group and an aromatic functional group, wherein the carbon of the aromatic functional group is separated from the carbon of the carbonyl of the anhydride by a carbon chain of 1 to 3 non-aromatic carbon atoms, inclusive.

Description

[0001] The present disclosure relates to curable silicone elastomer compositions having enhanced adhesion properties to a variety of substrates (hereinafter "curable silicone elastomer compositions"). Elastomers prepared by curing the aforementioned compositions can be adhered to a variety of substrates to form a composite comprising the elastomer prepared from the curable silicone elastomer composition and the substrate. Methods for adhering the elastomer made from the curable silicone elastomer composition to a substrate are also provided.

[0002] The curable silicone elastomer compositions cure to provide silicone elastomer materials (also known as silicone rubbers). One suitable curing process is via an addition curing mechanism, otherwise described as a hydrosilylation process using a platinum group catalyst.

[0003] Addition curable silicone elastomers generally have poor adhesion to plastics. Traditionally, the adhesion of silicone elastomers has been increased by modifying the silicone matrix or the substrate surface (e.g., by priming) and surface activation forms (e.g., plasma treatment) and other methods. Priming the substrate surface with a primer was initially utilized to overcome this problem. However, several problems have arisen with the use of methods requiring primers and / or high energy surface pretreatments (e.g., irradiation by exposure to a plasma, corona, flame, UV, or UV-ozone source to activate the surface for adhesion).

[0004] Primer methods are cumbersome, not only because they can lead to unreliable production rates, quality control problems, and actual reliability problems with the parts / articles being manufactured. Primers also have the disadvantage of typically containing volatile organic solvents.

[0005] Accordingly, it is desirable to avoid the use of primers, if possible, and this has been later achieved by the use of self-adhesive silicone elastomer materials that will have satisfactory adhesion without the need for primed surfaces, i.e., they are able to adhere to substrates made of, for example, thermoplastic materials, organic resin-based materials, or both thermoplastic materials and organic resin-based materials, during the curing process, by directly contacting them with the substrate before or during the curing process.

[0006] It is known that the adhesion of addition curable silicone elastomers can be improved by incorporating adhesion additives containing reactive functional groups, including but not limited to alkoxysilane, epoxy, and carboxyl groups. However, their use in a variety of applications is limited because they do not form strong enough adhesive bonds with plastics and thermoplastic substrates such as polycarbonates. For example, alkoxysilane coupling agents are sometimes used to achieve adhesion to plastics, but they are prone to side reactions such as self-reactions and release volatile alcohols upon reaction, which reduces their effectiveness.

[0007] In another alternative proposal, it has been suggested to incorporate in the polycarbonate substrate a silicon hydride addition curable silicone elastomer crosslinker, such as an organohydrogenpolysiloxane. However, it has been found that such an approach has a negative effect on the physical properties of the polycarbonate itself, thereby inhibiting the resin from performing its own properties. The physical bonding approach leaves the possibility that the two pieces can be detached by physical force.

[0008] The use of a silicone elastomer, such as a self-adhesive silicone elastomer, is a preferred alternative because it can impart better productivity, quality control, and reliability to the component / article at least in part due to the removal of the need to use a primer or surface pretreatment.

[0009] The durability of the bond between a self-adhesive silicone material and various non-silicone substrates, such as thermoplastic substrates, organic resin substrates metals, or thermoplastic and organic resin substrates, is very important for the successful use of the combination, but it is still a technical challenge to provide such a compound that has good adhesion to various substrates.

[0010] The present disclosure relates to a curable silicone elastomer composition that is capable of achieving adhesion to plastic / thermoplastic / resin material substrates and comprises:

[0011] (A) one or more organopolysiloxanes containing at least two unsaturated groups per molecule selected from alkenyl groups and alkynyl groups, and having a viscosity at 25 °C in the range of 1000 mPa.s to 500,000 mPa.s, but not containing anhydride functional groups;

[0012] (B) a curing agent comprising

[0013] (B)(i) an organic peroxide radical initiator; or

[0014] (B)(ii) a silicon hydride addition cure catalyst package comprising

[0015] a. a silicone compound having at least two, alternatively at least three Si-H groups per molecule; and

[0016] b. a silicon hydride addition catalyst;

[0017] (C) at least one reinforcing filler and optionally one or more non-reinforcing fillers; and

[0018] (D) a polyorganosiloxane having

[0019] (i) at least one unsaturated group per molecule selected from alkenyl groups and alkynyl groups, and

[0020] (ii) an anhydride functional group and an aromatic functional group, wherein the carbon of the aromatic functional group is separated from the carbon of the carbonyl of the anhydride by a carbon chain of 1 to 3 non-aromatic carbon atoms, inclusive.

[0021] The above compositions enable primerless bonding of plastics with addition-curable silicone elastomers, wherein Component D is a tackifier that is free of Si-H groups and / or alkoxy silane groups that provides primerless bonding to commercially important engineered thermoplastics.

[0022] Component (A) is one or more organopolysiloxanes containing at least two unsaturated groups per molecule selected from alkenyl groups and alkynyl groups, and the organopolysiloxane has a viscosity at 25 °C in the range of 1000 mPa.s to 500,000 mPa.s, but does not contain anhydride functional groups.

[0023] In one embodiment, each of the one or more organopolysiloxanes (A) contains at least 2 alkenyl and / or alkynyl groups bonded to a silicon atom per molecule, and has a viscosity at 25 °C of 1000 mPa.s to 500,000 mPa.s, alternatively 1000 mPa.s to 150,000 mPa.s at 25 °C, alternatively 1000 mPa.s to 100,000 mPa.s at 25 °C, alternatively 1000 mPa.s to 75,000 mPa.s at 25 °C, unless otherwise indicated, using a rheometer such as an Anton-Paar MCR-301 rheometer equipped with a 25 mm cone-plate fixture and operated at 25 °C. Unless otherwise indicated, the viscosity is reported as the 0-shear viscosity, which means the value extrapolated to 0 shear rate from the statistically significant, rate-independent Newtonian region of a viscosity versus shear rate sweep. Alternatively, if a Brookfield TM Rotational viscometer measurements are required viscosities, wherein all viscosity measurements are made at 25 °C unless otherwise indicated.

[0024] Each of the at least two unsaturated groups per molecule can be the same or different and is selected from alkenyl groups and alkynyl groups, alternatively alkenyl groups and alkynyl groups having 2 to 12 carbons, alternatively alkenyl groups and alkynyl groups having 2 to 6 carbons. Examples of alkenyl groups include vinyl, allyl, butenyl, pentenyl, cyclohexenyl, and hexenyl groups. Examples of alkynyl groups include ethynyl, propynyl, butynyl, pentynyl, cyclohexynyl, and hexynyl groups. The unsaturated groups can be pendant or terminal or in both positions, i.e., they can be present on any siloxy unit of the organopolysiloxane (A).

[0025] Component (A) can be a linear and / or branched organopolysiloxane comprising a plurality of units of formula (1)

[0026] R' a SiO 4-a / 2 (1)

[0027] wherein each R' can be the same or different and represents a hydrocarbon group having 1 to 18 carbon atoms, a substituted hydrocarbon group having 1 to 18 carbon atoms, or a hydrocarbonoxy group having up to 18 carbon atoms, and has on average a value of a of 1 to 3, preferably 1.8 to 2.2.

[0028] For the purposes of the present application, “substituted” means that one or more hydrogen atoms in a hydrocarbon group are replaced by another substituent. Examples of such substituents include, but are not limited to, halogen atoms such as chlorine, fluorine, bromine, and iodine; halogen atom-containing groups such as chloromethyl, perfluorobutyl, trifluoroethyl, trifluoropropyl, and nonafluorohexyl; oxygen atoms; oxygen atom-containing groups such as (meth)acrylic acid and carboxyl groups; nitrogen atoms; nitrogen atom-containing groups such as amino, amido, and cyano functional groups; sulfur atoms; and sulfur atom-containing groups such as mercapto groups.

[0029] Unless otherwise indicated, when R is typically an alkyl group, such as a methyl group, the siloxy units can be described by the shorthand (abbreviated) nomenclature of “M”, “D”, “T”, and “Q” (for further teaching on organosilicon nomenclature, see Walter Noll, Chemistry and Technology of Silicones, dated 1962, Chapter I, pages 1-9). M units correspond to siloxy units with a = 3, i.e. R3SiO 1 / 2 ; D units correspond to siloxy units with a = 2, i.e. R2SiO 2 / 2 ; T units correspond to siloxy units with a = 1, i.e. R1SiO 3 / 2 ; and Q units correspond to siloxy units with a = 0, i.e. SiO 4 / 2 .

[0030] Examples of component (A) are polydiorganosiloxanes containing alkenyl or alkynyl groups at both terminals but typically containing alkenyl groups, and which are represented by the general formula (I):

[0031] R'R"R"'SiO-(R"R"'SiO) m -SiOR”'R"R'(I)

[0032] In formula (I), each R' is an alkenyl or alkynyl group, but typically an alkenyl group, which typically contains 2 to 10 carbon atoms, such as vinyl, allyl, and 5-hexenyl.

[0033] R" does not contain an ethylenically unsaturated group. Each R" can be the same or different and is selected from the group consisting of monovalent saturated hydrocarbon groups (which typically contain from 1 to 10 carbon atoms) and monovalent aromatic hydrocarbon groups (which typically contain from 6 to 12 carbon atoms). R" can be unsubstituted or substituted with one or more groups that do not interfere with the curing of the composition of the present application, such as halogen atoms. R'" is R' or R" and m represents the degree of polymerization suitable for component (A) to have a viscosity within the range discussed below.

[0034] Typically, all of the R" and R'" groups contained in the compound according to formula (I) are methyl groups. Alternatively, at least one R" and / or R'" group in the compound according to formula (I) is a methyl group and the other group is a phenyl or 3,3,3-trifluoropropyl group. This preference is based on the availability of reactants typically used to make polydiorganosiloxanes (component (A)) and the desired properties of the cured elastomer made from a composition comprising such polydiorganosiloxanes.

[0035] Particularly preferred examples of the group R' include methyl, ethyl, propyl, butyl, vinyl, cyclohexyl, phenyl, tolyl groups, chloro- or fluoro-substituted propyl groups such as 3,3,3-trifluoropropyl, chlorophenyl, β-(perfluorobutyl)ethyl, or chlorocyclohexyl groups. Preferably, at least some and more preferably substantially all of the R ’ groups are methyl groups. Some of the R' groups can be phenyl groups or fluoro groups. In one alternative, the polydiorganosiloxane is predominantly a polydialkylsiloxane and / or a polydialkylalkylphenylsiloxane having at least two alkenyl groups per molecule. In another alternative, the polydiorganosiloxane is predominantly a polydimethylsiloxane having at least two alkenyl groups per molecule. They are preferably substantially linear materials terminated by siloxane groups of the formula R"3SiO 1 / 2 It will be appreciated that the rate of cure and physical properties of the curable composition are influenced by the structure and functionality of component (A). For example, it can be advantageous in some embodiments to use branched, resinous or cyclic organopolysiloxanes having pendant alkenyl or alkynyl groups as part or all of component (A).

[0036] The viscosity of the organopolysiloxane (A) at 25°C is determined using a rheometer or a Brookfield rotational viscometer with a spindle (LV-4) and according to the manufacturer's instructions, typically using a polymer viscosity change speed. TM The viscosity of the organopolysiloxane (A) at 25°C is determined using a rheometer or a Brookfield rotational viscometer with a spindle (LV-4) and according to the manufacturer's instructions, typically using a polymer viscosity change speed.

[0037] Examples of organic polysiloxane (A) that can be used include vinyl dimethylsiloxy-terminated dimethylsiloxane-vinylmethylsiloxane copolymer, vinyl dimethylsiloxy-terminated polydimethylsiloxane, vinylmethylhydroxy-siloxy-terminated dimethylsiloxane-vinylmethylsiloxane copolymer, and mixtures thereof.

[0038] The organic polysiloxane (A) can be a single polymer, or a combination of two or more different polymers. Alternatively or in the alternative, the organic polysiloxane (A) can be a silicone resin comprising [T] units and / or [Q] units as defined above. For example, the silicone resin of component (A) can be characterized as a DT resin, an MQ resin, an MDQ resin, and the like, but in each case must comprise at least two unsaturated groups, typically alkenyl groups as discussed above.

[0039] The organic polysiloxane (A) is present in the composition at a level of 10 to 85 weight percent based on the total weight of the composition, alternatively 20 to 80 weight percent based on the total weight of the composition, alternatively 20 to 75 weight percent based on the total weight of the composition, alternatively 30 to 65 weight percent based on the total weight of the composition.

[0040] B) Curing agent

[0041] The compositions as described herein can be cured with an organic peroxide radical initiator (catalyst) (B) (i) or a mixture of different types of peroxides (radical initiators / catalysts).

[0042] The peroxide catalyst / radical initiator can be any of the well-known commercial peroxides used to cure silicone and / or fluorosilicone elastomer compositions. The amount of organic peroxide used is determined by the nature of the curing process, the organic peroxide used, and the composition used. Typically, the amount of organic peroxide used in the compositions as described herein is 0.2 to 3 weight percent, alternatively 0.2 to 2 weight percent, in each case based on the weight of the composition.

[0043] Suitable organic peroxides include substituted or unsubstituted dialkyl peroxides, alkyl arylacyl peroxides, diaroyl peroxides, such as benzoyl peroxide and 2,4-dichlorobenzoyl peroxide, di-tert-butyl peroxide, dicumyl peroxide, lauroyl peroxide, t-butylcumyl peroxide, bis(t-butylperoxyisopropyl)benzene, cyclohexanone peroxide, cumene hydroperoxide, t-butyl hydroperoxide, bis(t-butylperoxy)-2,5-dimethylhexyne 2,4-dimethyl-2,5-di(t-butylperoxy)hexane, di-tert-butyl peroxide, and 2,5-bis(t-butylperoxy)-2,5-dimethylhexane.

[0044] Alternatively, the composition can be cured using a hydrosilylation catalyst package (B)(ii) in the form of

[0045] (B)(ii)(a) an organosilicon compound having at least 2, alternatively at least 3, Si-H groups per molecule; and

[0046] (B)(ii)(b) a hydrosilylation catalyst.

[0047] Component (B)(ii)(a) is a crosslinker in the form of an organosilicon compound containing at least 2 or 3 silicon-bonded hydrogen atoms per molecule. Component (B)(ii)(a) typically contains 3 or more silicon-bonded hydrogen atoms, so the hydrogen atoms can react with the unsaturated alkenyl or alkynyl groups of the polymer (A) to form a network therewith and thereby cure the composition. When the polymer (A) has more than (>) 2 alkenyl or alkynyl groups per molecule, some or all of component (B)(ii)(a) per molecule can alternatively have 2 silicon-bonded hydrogen atoms.

[0048] The structure of the organosilicon compound can be linear, branched, cyclic, or resinous. The cyclic silanes and siloxanes can have from 3 to 12 silicon atoms, or from 3 to 10 silicon atoms, or from 3 to 4 silicon atoms. In the acyclic polysilanes and polysiloxanes, the silicon-bonded hydrogen atoms can be positioned at terminal, pendant, or both terminal and pendant positions.

[0049] Examples of suitable organohydrogensilanes that can be used as crosslinkers can include diphenylsilane, 2-chloroethylsilane, bis[(p-dimethylsilyl)phenyl]ether, 1,4- dimethyldisilyl ethane, 1,3,5-tri(dimethylsilyl)benzene, 1,3,5-trimethyl-1,3,5-trisilane, poly(methylsilylene)phenylene, and poly(methylsilylene)methylene. In some examples, the organohydrogensilane can have the formula HR 1 2Si-R 2 -SiR 1 2H, wherein R 1 is a C1to C 10 hydrocarbyl group or a C1to C 10 halogen-substituted hydrocarbyl group, and R 2 is a hydrocarbylene group free of aliphatic unsaturation having a formula selected from 1,4-disubstituted phenyl or 1,3-disubstituted phenyl, 4,4'-disubstituted-1,1'-biphenyl or 3,3'-disubstituted-1,1'-biphenyl, or p-disubstituted or m-disubstituted Ph(C g H 2g )Ph.

[0050] The molecular configuration of the organopolysiloxane containing at least 2 or 3 silicon-bonded hydrogen atoms per molecule (B) (ii) (a) is not particularly limited, and it can be linear, linear with some branches, cyclic, or based on silicone resin. Although the molecular weight of this component is not particularly limited, using a rheometer as described above or a cup / spindle method according to ASTM D 1084 Method B, using a Brookfield DV-I+ viscometer, the viscosity of the component (B) (ii) (a) is preferably 0.001 to 100 Pa.s at 25°C. TM The viscosity of the spindle measurement most suitable for the viscosity range of the RV or LV range is usually 0.001 to 50 Pa.s at 25°C to obtain good miscibility with the polymer (A).

[0051] The silicon-bonded organic group for component (B) (ii) (a) can be exemplified by methyl, ethyl, propyl, butenyl, pentenyl, hexyl, or similar alkyl groups; phenyl, tolyl, xylyl, or similar aryl groups; 3-chloropropyl, 3,3,3-trifluoropropyl, or similar halogenated alkyl groups, of which methyl and phenyl groups are preferred.

[0052] The organopolysiloxane containing at least 2 or 3 silicon-bonded hydrogen atoms per molecule (B) (ii) (a) is usually added in an amount such that the molar ratio of the total number of silicon-bonded hydrogen atoms in component (B) (ii) (a) to the total number of alkenyl and / or alkynyl groups in polymer (A) is 0.5:1 to 20:1. When this ratio is less than 0.5:1, a well-cured composition is not obtained. When this ratio exceeds 20:1, there is a tendency for the hardness of the cured composition to increase when heated.

[0053] Examples of the organopolysiloxane containing at least 2 or 3 silicon-bonded hydrogen atoms per molecule (B) (ii) (a) include, but are not limited to:

[0054] (a’) trimethylsiloxy-terminated methylhydrogenpolysiloxane,

[0055] (b’) trimethylsiloxy-terminated polydimethylsiloxane-methylhydrogensiloxane,

[0056] (c’) dimethylhydrogensiloxy-terminated dimethylsiloxane-methylhydrogensiloxane copolymer,

[0057] (d’) dimethylsiloxane-methylhydrogensiloxane cyclic copolymer,

[0058] (e’) copolymer and / or silicone resin consisting of (CH3)2HSiO 1 / 2 units, (CH3)3SiO 1 / 2 units, and SiO 4 / 2 units,

[0059] (f’) copolymer and / or silicone resin consisting of (CH3)2HSiO1 / 2 unit and SiO 4 / 2 copolymers and / or silicone resins composed of units,

[0060] (g') is derived from ((CH3)2HSiO 1 / 2 Unit, SiO 4 / 2 Unit and (C6H5)3SiO 1 / 2 Units, and copolymers and / or silicone resins in which methyl groups are replaced by phenyl or other alkyl groups.

[0061] Alternatively, component (B)(ii)(a) crosslinking agent may be a filler, such as silica treated with one of the above substances.

[0062] Component (B)(ii)(a) can be exemplified by the following compounds: methylhydrosiloxanes terminated at both ends of the molecule by trimethylsiloxy groups; copolymers of methylhydrosiloxanes and dimethylsiloxanes terminated at both ends of the molecule by trimethylsiloxy groups; dimethylsiloxanes terminated at both ends of the molecule by dimethylhydrosiloxy groups; copolymers of methylhydrosiloxanes and dimethylsiloxanes terminated at both ends of the molecule by dimethylhydrosiloxy groups; copolymers of methylhydrosiloxanes and methylphenylsiloxanes terminated at both ends of the molecule by dimethylphenylsiloxy groups; cyclic methylhydrosiloxanes; and compounds derived from (CH3)2HSiO 1 / 2 Siloxane units and SiO 4 / 2 A copolymer composed of units; consisting of (CH3)2HSiO 1 / 2 Siloxane unit, (CH3)3SiO 1 / 2 Siloxane units and SiO 4 / 2 The unit, the copolymer of the aforementioned organopolysiloxanes, wherein some or all of the methyl groups are replaced by ethyl, propyl or similar alkyl groups; phenyl, tolyl or similar aryl groups; 3,3,3,-trifluoropropyl or similar haloalkyl groups; or a mixture of two or more of the aforementioned organopolysiloxanes.

[0063] The organosilicon compound crosslinking agent (B)(ii)(a) is typically present in a certain amount in the curable organosilicon elastomer composition such that the ratio of the molar number of silicon-bonded hydrogen atoms in component (B)(ii)(a) to the molar number of alkenyl groups in component (A) is in the range of (0.7:1.0) to (5.0:1.0), preferably (0.9:1.0) to (2.5:1.0), and most preferably (0.9:1.0) to (2.0:1.0).

[0064] The content of silicon-bonded hydrogen (Si-H) in component (B)(ii)(a) and the content of unsaturated groups in component (a) are both determined using quantitative infrared analysis according to ASTM E168. In this case, when relying on a hydrosilylation curing process, the ratio of silicon-bonded hydrogen to alkenyl (vinyl) and / or alkynyl groups is important. Generally, this is determined by calculating the total weight % of alkenyl groups (e.g., vinyl) [V] in the composition and the total weight % of silicon-bonded hydrogen [H] in the composition, and assuming a molecular weight of 1 for hydrogen and a molecular weight of 27 for vinyl, the molar ratio of silicon-bonded hydrogen to vinyl is 27[H] / [V].

[0065] Typically, depending on the number of unsaturated groups in component (A) and the number of Si-H groups in component (B)(ii)(a), component (B)(ii)(a) will be present in an amount of 0.1% to 40% by weight of the total composition, alternatively 0.5% to 20% by weight of the total composition, alternatively 0.5% to 10% by weight of the total composition, and also alternatively 1% to 5% by weight of the total composition.

[0066] Components (B)(ii)(b) are at least one hydrosilylation (addition) catalyst. These hydrosilylation (addition) catalysts are typically selected from catalysts of platinum group metals (platinum, ruthenium, osmium, rhodium, iridium, and palladium), or compounds of one or more of these metals. Platinum and rhodium compounds are preferred due to the high activity levels of these catalysts in hydrosilylation reactions. Components (B)(ii)(b) catalyze the reaction between the alkenyl groups (e.g., vinyl groups) of component (A) and the Si-H groups of component (B)(ii)(a), thereby generating a crosslinked network when the curable silicone elastomer composition is cured into its corresponding elastomer.

[0067] Catalysts (B)(ii)(b) may be platinum group metals, platinum group metals deposited on a support (such as activated carbon, metal oxides such as alumina or silica, silica gel or charcoal powder), or compounds or complexes of platinum group metals.

[0068] Examples of preferred hydrosilylation catalysts (B)(ii)(b) are platinum-based catalysts, such as platinum black, platinum on various solid supports, chloroplatinic acid, alcoholic solutions of chloroplatinic acid, and complexes of chloroplatinic acid with alkene-bonded unsaturated compounds (such as alkenes) and organosiloxanes containing silicon-bonded alkene-bonded unsaturated hydrocarbon groups. Soluble platinum compounds that can be used include, for example, platinum-olefin complexes of formula (PtCl2.olefin)2 and H(PtCl3.olefin), preferably in this context olefins having 2 to 8 carbon atoms, such as isomers of ethylene, propylene, butene, and octene, or cycloalkanes having 5 to 7 carbon atoms, such as cyclopentene, cyclohexene, and cycloheptene. Other soluble platinum catalysts include, for example, platinum-cyclopropane complexes of formula (PtCl2C3H6)2, reaction products of hexachloroplatinic acid with alcohols, ethers, and aldehydes, or mixtures thereof, or reaction products of hexachloroplatinic acid with methylvinylcyclotetrasiloxane in the presence of sodium bicarbonate in an ethanol solution. Platinum catalysts with phosphorus, sulfur, and amine ligands, such as (Ph3P)2PtCl2, and platinum-vinylsiloxane complexes, such as symmetrical divinyltetramethyldisiloxane, can also be used.

[0069] Therefore, specific examples of suitable platinum-based catalysts include

[0070] (i) A complex of chloroplatinic acid as described in US 3,419,593 with an organosiloxane containing an olefinic unsaturated hydrocarbon group.

[0071] (ii) Chloroplatinic acid in hexahydrate or anhydrous form;

[0072] (iii) A platinum-containing catalyst, which is obtained by a method comprising the steps of reacting chloroplatinic acid with an aliphatic unsaturated organosilicon compound (such as divinyltetramethyldisiloxane);

[0073] (iv) olefin-platinum-silyl complexes as described in U.S. Patent 6,605,734, such as (COD)Pt(SiMeCl2)2, wherein “COD” is 1,5-cyclooctadiene; and / or

[0074] (v) Karstedt catalysts can be used with platinum-divinyltetramethyldisiloxane complexes that typically contain about 1% by weight of platinum in solvents such as toluene. These are described in US3,715,334 and US3,814,730.

[0075] The hydrosilylation catalyst (B)(ii)(b) of the hydrosilylation-curable organosilicon elastomer composition is present in the total composition in a catalytic amount, i.e., the amount or quantity sufficient to catalyze the addition / hydrosilylation reaction and cure the composition into an elastomer material under desired conditions. Different contents of the hydrosilylation catalyst (B)(ii)(b) can be used to tailor the reaction rate and curing kinetics. Based on the weight of the polymer (A) and filler (C) in the composition, the catalytic amount of the hydrosilylation catalyst (B)(ii)(b) is typically between 0.01 ppm and 10,000 parts by weight of platinum group metals; alternatively between 0.01 ppm and 5,000 ppm; alternatively between 0.01 ppm and 3,000 ppm; and alternatively between 0.01 ppm and 1,000 ppm. In specific embodiments, the catalytic amount of the catalyst may be in the range of 0.01 ppm to 1,000 ppm, or 0.01 ppm to 750 ppm, or 0.01 ppm to 500 ppm, or 0.01 ppm to 100 ppm of metal, based on the weight of the composition. This range may refer only to the metal content within the catalyst or to the entirety of the catalyst (including its ligands) as detailed, but typically these ranges refer only to the metal content within the catalyst. The catalyst may be added as a single substance or as a mixture of two or more different substances. Typically, depending on the form / concentration of the catalyst package provided, the amount of catalyst present in the hydrogenatable silanization-curable silicone elastomer composition will be from 0.001 wt.% to 3.0 wt.% of the composition.

[0076] Component (C) is one or more reinforcing fillers preferably provided in finely crushed form, optionally in combination with one or more reinforcing fillers and / or non-reinforcing fillers.

[0077] The reinforcing filler of component (C) can be exemplified as preferably finely crushed pyrolytic silica and / or preferably finely crushed precipitated silica and / or colloidal silica and / or suitable silicone resin.

[0078] Precipitated silica pyrolysis method silica and / or colloidal silica because of their relatively high surface area (typically at least 50 μm²). 2 / g (according to the BET method of ISO 9277:2010), so they are particularly preferred. Typically used have a surface area of ​​50 to 450 m². 2 / g (according to the BET method of ISO 9277:2010), alternatively 50 to 300m 2 / g (according to the BET method of ISO 9277:2010) of filler. All of these types of silica are commercially available.

[0079] When the reinforcing filler (C) has natural hydrophilicity (such as untreated silica filler), it is usually treated with a treatment agent to impart hydrophobicity. Surface-modified reinforcing filler (C) does not clump and can be uniformly incorporated into the organopolysiloxane / polydiorganosiloxane polymer (A) described below, because the surface treatment makes the filler easily wetted by the organopolysiloxane / polydiorganosiloxane polymer (A).

[0080] Typically, the reinforcing filler (C) can be surface-treated with any low molecular weight organosilicon compound disclosed in the art that is suitable for preventing wrinkling of the organosiloxane composition during processing. For example, organosilicones, polydiorganosiloxanes, or organosilazanes, such as hexaalkyldisilazanes or short-chain siloxane diols, can impart hydrophobicity to the filler and thus make it easier to process and obtain a homogeneous mixture with other components. Specific examples include, but are not limited to, silanol-terminated trifluoropropylmethylsiloxane, silanol-terminated vinylmethyl (ViMe)siloxane, silanol-terminated MePhsiloxane, liquid hydroxy-dimethyl-terminated polydiorganosiloxane containing an average of 2 to 20 repeating units of diorganosiloxane per molecule, hydroxy-dimethyl-terminated phenylmethylsiloxane, hexaorganodisiloxanes such as hexamethyldisiloxane, divinyltetramethyldisiloxane; hexaorganodisilazanes such as hexamethyldisilazane (HMDZ), divinyltetramethyldisilazane and tetramethyldi(trifluoropropyl)disilazane; hydroxy-dimethyl-terminated polydimethylmethylvinylsiloxane, octamethylcyclotetrasiloxane and silanes, including but not limited to methyltrimethoxysilane, dimethyldimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, trimethylchlorosilane, dimethyldichlorosilane, trichloromethylsilane. A small amount of water can be added together with the silica treatment agent, which is used as a processing aid.

[0081] Surface treatment can be performed before or in situ (i.e., by blending these components together at room temperature or higher until the filler is fully treated, in the presence of at least a portion of the other components of the composition herein). Typically, untreated reinforcing filler (C) is treated in situ with a treatment agent in the presence of a polydiorganosiloxane polymer (A), which results in the preparation of a silicone elastomer matrix material, which can then be blended with the other components.

[0082] Based on the weight percentage of the solid content of the composition, the amount of reinforcing filler (C) present is from 5.0 wt% to 40 wt% of the solid content of the composition, alternatively from 7.5 wt% to 35 wt% of the solid content of the composition, alternatively from 10.0 wt% to 35 wt%. Therefore, the amount of reinforcing filler (C), such as the silica and / or silicone resins subdivided herein, can be, for example, from 2.0 wt% to 20 wt% of the total composition, alternatively from 2.5 wt% to 15 wt% of the total composition. In some cases, based on the weight of the total composition, the amount of reinforcing filler can be from 5.0 wt% to 15 wt%.

[0083] Non-reinforcing fillers may optionally be included in component (C) of this document. These non-reinforcing fillers may include, for example, pulverized quartz, calcium carbonate, diatomaceous earth, barium sulfate, iron oxide, titanium dioxide and carbon black, talc, wollastonite, alumina, (anhydrous) calcium sulfate, gypsum, calcium sulfate, magnesium carbonate, clays such as kaolin, aluminum hydroxide, magnesium hydroxide (brucite), graphite, copper carbonate such as malachite, nickel carbonate such as zarachite, barium carbonate such as barite, and / or strontium carbonate such as strontium sapphire.

[0084] Other non-reinforcing fillers may include alumina, selected from the following silicates: olivine; garnet; aluminosilicates; cyclosilicates; chain silicates; and platy silicates. Olivine includes silicate minerals such as, but not limited to, forsterite and Mg2SiO4. Garnet includes ground silicate minerals such as, but not limited to, pyrope; Mg3Al2Si3O4. 12 Grossular garnet and Ca2Al2Si3O 12 Aluminosilicates include milled silicate minerals such as, but not limited to, sillimanite; Al₂SiO₅; mullite; 3Al₂O₃·2SiO₂; kyanite; and Al₂SiO₅. Cyclosilicates can be used as non-reinforcing fillers; these include silicate minerals such as, but not limited to, cordierite and Al₃(Mg,Fe)₂[Si₄AlO₂]. 18 Chain silicates include ground silicate minerals, such as, but not limited to, wollastonite and Ca[SiO3]. Flake silicates may alternatively or otherwise be used as non-reinforcing fillers, wherein suitable classes contain silicate minerals, such as, but not limited to, mica; K2Al 14 [Si6Al2O 20 (OH)4; pyrophyllite; Al4[Si8O 20 (OH)4; Talc; Mg6[Si8O 20 (OH)4; serpentine, for example asbestos; kaolinite; Al4[Si4O] 10[(OH)8; and vermiculite. In an alternative form, the filler will be selected from one or more of the following: pyrolytic silica, precipitated silica, calcium carbonate, talc, mica, quartz and alumina.]

[0085] As previously noted, component (D) as described above is a polyorganosiloxane having the following characteristics.

[0086] (i) Each molecule contains at least one unsaturated group selected from alkenyl and ynyl groups, and

[0087] (ii) an anhydride functional group and an aromatic functional group, wherein the carbon of the aromatic functional group is separated from the carbon of the carbonyl group of the anhydride by a carbon chain of 1 to 3 non-aromatic carbon atoms including the endpoints.

[0088] Component (D) can be prepared according to the applicant’s PCT / US20 / 044709 (published as WO 2021 / 0260055), the contents of which are incorporated herein by reference.

[0089] Component (D) may have the same general structure as linear or branched organopolysiloxane component (A), that is, it may be linear or branched organopolysiloxane and the unsaturated groups of component (D)(i) are the same as those in component (A); the difference is that component (D) may have a viscosity of 5 to above 100,000 mPa·s at 25°C; and some of the unsaturated groups in component (A) are replaced by anhydride functional groups of (D)(ii), resulting in components (D)(i) and (D)(ii).

[0090] This is achieved using a functionalization reaction that introduces anhydride functional groups onto polyorganosiloxanes via free radical grafting as described below.

[0091] Anhydride functional groups can be added to polysiloxanes via free radical grafting. For example, alkenyl-functionalized polysiloxanes (e.g., vinyl-functionalized polyorganosiloxanes) can be mixed with unsaturated anhydrides (e.g., maleic anhydride) in the presence of a free radical initiator, and a free radical grafting reaction can occur between the alkenyl group of the polysiloxane and the unsaturated portion of the anhydride to graft the anhydride onto the polyorganosiloxane. This reaction is typically carried out with an aromatic initiator and / or in an aromatic solvent, which results in the free radicals of the initiator and / or solvent also grafting onto the anhydride. In this application, it is required that unsaturated and anhydride groups coexist on the same molecule. To ensure this, i.e., a partial conversion close to 50% to obtain an average of one anhydride and one vinyl group on the terminal functionalized siloxane, the method is controlled by using an anhydride reagent that is stoichiometrically insufficient relative to the vinyl group on the siloxane.

[0092] As an example, where: R 4 and R 5Where is an alkyl group and Vi refers to a vinyl group, vinyl-functionalized polyorganosiloxanes can be mixed with maleic anhydride along with a free radical initiator such as benzoyl peroxide in an aromatic solvent (such as xylene or toluene), and then heated to initiate a free radical reaction:

[0093]

[0094] When an anhydride with insufficient stoichiometry is used, the major reaction product obtained is (a) below, although some of (b) and (c) may also exist depending on the molar ratio of the reactants:

[0095] (a) Monofunctional polyorganosiloxanes: ViR 4 2SiO-(R 5 2SiO) m -SiR 4 2A'

[0096] (b) Difunctionalized polyorganosiloxanes: A'R 4 2SiO-(R 5 2SiO) m -SiR 4 2A';

[0097] (c) Unreacted vinyl-functionalized polysiloxanes: ViR 4 2SiO-(R 5 2SiO) m -

[0098] SiR 4 2Vi;

[0099] And A' is:

[0100]

[0101] Where X is an aromatic group, which is a residue of the solvent (e.g., tolyl or xylyl) or a residue of the initiator (e.g., benzoyl).

[0102] In a preferred embodiment, the polymer backbone of the siloxane starting material can be a dimethylmethylalkenyl copolymer backbone, typically a dimethylmethylvinyl copolymer backbone, in which case the side group A' can be designed to partially replace the alkenyl (vinyl) side groups of the starting material. Therefore, component (D) can comprise a monofunctionalized polyorganosiloxane of the following formula.

[0103] ViR 4 2SiO-(R 5 2SiO) m -SiR 4 2A' or

[0104] A'R 4 2SiO-(R 5 2SiO) m -SiR 4 2A'

[0105] Each R 4 It is an alkyl group, each R 5 It is an alkyl group, an alkenyl group, an alkynyl group, or A', and A' is:

[0106]

[0107] Wherein X is an aromatic group, and each molecule contains at least one alkenyl or alkynyl group. In one embodiment, X can be any suitable aromatic group, such as, but not limited to, a benzoyl group, a tolyl group, or a xylyl group.

[0108] The average concentration of anhydride functional groups (D)(ii) on the second polyorganosiloxane of component (D) can be determined based on the number of reactive sites (e.g., alkenyl groups) in the polyorganosiloxane before anhydride functionalization, and then by measuring the ratio of anhydride groups to the number of reactive sites in component (D). This can be achieved by using... 1 This is achieved by measuring the number of reactive sites and anhydride groups using 1H nuclear magnetic resonance (NMR) spectroscopy or alternatively by Fourier transform infrared (FTIR) spectroscopy. For example, using... 1 ¹H NMR spectroscopy, using 1,4-dioxane as an internal standard, measures the number of reactive sites and anhydride groups. The concentrations of functional groups such as alkenes and anhydrides can be calculated using the following methods:

[0109] C x =(I x / I is (N) is / N x (C) is )

[0110] Among them: I x The integral area of ​​the functional group of interest (6.3-5.6 ppm for alkenes and 3.5-2.0 ppm for anhydrides), I is The integral area of ​​the internal standard (3.68 ppm), N is It is the number of cores of the internal standard (in this case, N). is =8), N x The number of nuclei of the functional group of interest (6 for alkenes and 5 for anhydrides), C x It is the concentration of the functional groups of interest and C is It is the concentration of the internal standard.

[0111] Depending on the intended use of the curable silicone elastomer composition, optional additives may be present in the composition. Examples include one or more curing inhibitors, release agents, peroxides and / or pigments, conductive fillers, thermally conductive fillers, pot life extenders, flame retardants, lubricants, UV light stabilizers, bactericides, wetting agents, heat stabilizers, chain extenders, compression set additives, and plasticizers, etc.

[0112] When necessary, curing inhibitors are used to prevent or delay the curing process of the addition reaction, especially during storage. Optional curing (addition reaction) inhibitors for platinum-based catalysts are well known in the art and include hydrazine, triazole, phosphine, thiols, organonitrogen compounds, alkynols, methanesilylated alkynols, maleates, fumarates, olefinic or aromatic unsaturated amides, olefinic unsaturated isocyanates, alkenyl siloxanes, unsaturated hydrocarbon monoesters and diesters, conjugated alkenylenes, hydroperoxides, nitriles, and diazacyclopropanes. Alkenyl-substituted siloxanes as described in US3989667 can be used, with cyclic methylvinylsiloxanes being preferred.

[0113] Known inhibitors of hydrosilylation reactions include alkynyl compounds disclosed in US3445420. Alynyl alcohols, such as 2-methyl-3-butyn-2-ol, constitute a preferred class of inhibitors, which suppress the activity of platinum-containing catalysts at 25°C. Compositions containing these inhibitors typically require heating to 70°C or higher to achieve a feasible curing rate.

[0114] Examples of alkynols 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. Alynol derivatives may include those compounds having at least one silicon atom.

[0115] In some cases, inhibitor concentrations as low as 1 mole of inhibitor per mole of catalyst metal will confer satisfactory storage stability and curing rate when present. In other cases, an inhibitor concentration of up to 500 moles of inhibitor per mole of catalyst metal is required. The optimal concentration of a given inhibitor in a given composition can be readily determined by routine experiments. Depending on the concentration and form of the inhibitor chosen, it is typically present in the composition at an amount of 0.0125% to 10% by weight of the composition.

[0116] Dimethylvinyl polydiorganosiloxanes with viscosities ranging from 10 mPa·s to 750 mPa·s at 25°C may also exist. These dimethylvinyl polydiorganosiloxanes typically have a structure similar to component (A), and dimethylvinyl terminal groups may be present in the polydimethylsiloxane polymer chain, but a combination of vinylmethyl groups may be present along the length of the polymer chain. The main differences for these polymers are the chain length and the subsequent viscosity relative to component (A). The zero-shear viscosity of this type of polymer at 25°C ranges from 10 mPa·s to 750 mPa·s. Zero-shear viscosity is obtained by extrapolating the value obtained at low shear rates to zero, where the viscosity-shear rate curve is independent of the rate, a value independent of the testing method. The zero-shear viscosity of a substance at 25°C is typically determined using a rheometer such as the Anton-Paar MCR-301 rheometer equipped with a 25 mm cone plate clamp, or a viscometer such as the Brookfield, which utilizes a spindle (LV-1-LV-4) and adjusts the speed according to the polymer viscosity. TM The results were obtained using a rotational viscometer.

[0117] Examples of conductive fillers include metal particles, metal oxide particles, metal-coated metal particles (such as silver-plated nickel), metal-coated non-metallic core particles (such as silver-plated talc, mica, or quartz), and combinations thereof. Metal particles may be in the form of powder, flakes, or filaments, as well as mixtures or derivatives thereof.

[0118] Examples of thermally conductive fillers include boron nitride, aluminum oxide, metal oxides (such as zinc oxide, magnesium oxide, and aluminum oxide), graphite, diamond, and mixtures or derivatives thereof.

[0119] Examples of chain extenders include linear organopolysiloxanes containing two silicon-bonded hydrogen groups at the terminal positions. Such chain extenders differ from component (B)(ii)(a)—crosslinkers in the form of organosilicon compounds containing at least two or three silicon-bonded hydrogen atoms per molecule. Typically, chain extenders will have two Si-H groups, and crosslinkers will have at least three Si-H groups. Examples of chain extenders include, but are not limited to, disiloxanes or low-molecular-weight polyorganosiloxanes containing two silicon-bonded hydrogen atoms at the terminal positions. Chain extenders typically react with the alkenyl groups of polymers (i) and (ii) to link two or more molecules of polymers (i) and (ii) together and increase their effective molecular weight and the distance between potential crosslinking sites.

[0120] Disiloxanes are typically produced using the general formula (HR) a 2Si)2O represents this. When the chain extender is a polyorganosiloxane, it has the general formula HR. a 2SiO 1 / 2 The end unit and formula R bNon-terminal units of 2SiO. In these equations, R a and R b Each represents an unsubstituted or substituted monovalent hydrocarbon group that does not contain olefinic unsaturation and fluorine content, including but not limited to alkyl groups containing 1 to 10 carbon atoms, substituted alkyl groups containing 1 to 10 carbon atoms (such as chloromethyl), cycloalkyl groups containing 3 to 10 carbon atoms, aryl groups containing 6 to 10 carbon atoms, alkylaryl groups containing 7 to 10 carbon atoms (such as tolyl and xylyl), and aralkyl groups containing 7 to 10 carbon atoms (such as benzyl).

[0121] Other examples of chain extenders include tetramethyldihydrodisiloxane or dimethylhydrogen-terminated polydimethylsiloxane.

[0122] Based on the weight of polymers (i) and (ii), a chain extender may be added in amounts of 1 to 10 parts by weight, typically a combination of 1 to 10 parts / 100 parts of polymers (i) and (ii).

[0123] Examples of flame retardants include aluminum trihydrate, magnesium hydroxide, magnesium silicate, chlorinated paraffin, hexabromocyclododecane, triphenyl phosphate, dimethyl methylphosphonate, tris(2,3-dibromopropyl)(tribromo) phosphate, and mixtures or derivatives thereof.

[0124] Examples of pigments include iron oxide, carbon black, and mixtures or derivatives thereof.

[0125] Examples of lubricants include tetrafluoroethylene, resin powder, graphite, fluorinated graphite, talc, boron nitride, fluorinated oil, silicone oil, molybdenum disulfide, and mixtures or derivatives thereof.

[0126] Other additives include silicone fluids, such as trimethylsilyl or OH-terminated siloxanes. These trimethylsiloxy or OH-terminated polydimethylsiloxanes typically have a viscosity of <150 mPa·s at 25°C. When present, such silicone fluids may be present in the curable silicone elastomer composition in an amount ranging from 0.1% to 5% by weight, based on the total weight of the composition.

[0127] Curable silicone elastomer compositions may include:

[0128] A curable silicone elastomer composition that enables significant adhesion to thermoplastic substrates, organic resin substrates, or surfaces of both thermoplastic and organic resin substrates, and comprises:

[0129] Component A

[0130] One or more organopolysiloxanes containing at least two alkenyl groups per molecule and having a viscosity at 25°C in the range of 1000 mPa·s to 500,000 mPa·s, wherein the amount of the component is 10% to 85% by weight based on the total weight of the composition, alternatively 20% to 80% by weight based on the total weight of the composition, alternatively 20% to 75% by weight based on the total weight of the composition, alternatively 30% to 65% by weight based on the total weight of the composition;

[0131] Component B

[0132] When component (B) is (B)(i), the amount of organic peroxide present may be from 0.2% to 3% by weight, or alternatively from 0.2% to 2% by weight, based on the weight of the composition in each case.

[0133] Alternatively, component (B)(ii)(a): an organopolysiloxane containing at least two or three silicon-bonded hydrogen atoms per molecule, the amount of which is from 0.1% to 40% 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, and even alternatively from 1% to 5% by weight of the total composition;

[0134] Component (B)(ii)(b): at least one hydrosilylation catalyst, wherein the amount of the component is 0.01% to 10% by weight of the total composition, alternatively 0.01% to 5% by weight of the total composition, and even alternatively 0.05% to 2% by weight of the total composition;

[0135] Component (C): at least one reinforcing filler and optionally one or more non-reinforcing fillers, the amount of which is from 1 wt% to 80 wt% based on the total weight of the composition, alternatively from 1 wt% to 50 wt% based on the total weight of the composition, alternatively from 5 wt% to 50 wt% based on the total weight of the composition, and also alternatively from 8 wt% to 30 wt% based on the total weight of the composition;

[0136] It also contains component (D).

[0137] This disclosure is intended to include any combination of the above combinations, provided that the total composition percentage of components (A) to (D) and any optional additives constitute 100% by weight of the composition.

[0138] When curing via hydrosilylation, it is important to store the catalyst (B)(ii)(b) separately from the crosslinking agent (B)(ii)(a) to prevent premature curing during storage. Typically, the catalyst (B)(ii)(b) is included in part A of the composition, and the crosslinking agent (B)(ii)(a) and any optional inhibitors are stored in part B of the composition.

[0139] Optional additives (excluding inhibitors) may be included in either part (A) or part (B) or in both parts. They may also be added to the final mixture after parts (A) or parts (B) have been combined.

[0140] In one embodiment, a method for preparing an article or a composite component of an article is provided, the method comprising:

[0141] a) A mixture forming the curable silicone elastomer composition described herein, and

[0142] b) Optionally, the mixture is applied to the surface of the substrate after the substrate has been surface-treated, for example by plasma, corona and / or UV-C.

[0143] c) The mixture is cured at a temperature of 80°C to 250°C.

[0144] In step (a), when the composition is stored in multiple portions prior to use, the different portions are combined together and mixed uniformly, followed by optional subsequent steps such as the addition of any additional additives that may be required for the end use of the composition.

[0145] The substrate can be any suitable thermoplastic or organic resin substrate. Examples of substrates include acrylonitrile-butadiene-styrene, polyphenylene / styrene blends, polystyrene, polycarbonate (PC), polyurethane, styrene resin, polyethylene, polypropylene, acrylics, polymethacrylic acids, polyacrylamide, polyester, polyethylene terephthalate, polybutylene terephthalate (PBT), polyphenylene ether, polyphenylene sulfide, polysulfone, nylon, polyamide (PA), blends of polyamide resins with isotrimeric polystyrene, polyimide, fluoropolymers and liquid crystal resins, resin-free polyetherimide, phenolic resins, epoxy resins, epoxy molding compounds, urea resins, melamine resins, alkyd resins, acrylonitrile-butadiene-styrene, styrene-modified poly(phenylene ether), poly(phenylene sulfide), vinyl esters or polyphthalamides, and combinations thereof. Other substrates may include, for example, metals, cellulose, and fabrics / textiles, such as on cotton or other natural and synthetic fiber clothing. If desired, activation can be performed, for example, by plasma, corona, or UV-C activation of any of the above. Typically, when the composition is not self-adhesive, the compositions described herein can adhere to metal substrates such as silicon, aluminum, stainless steel alloys, titanium, copper, nickel, silver, gold, and combinations thereof.

[0146] The uniform mixing of the components of the curable silicone elastomer composition of the present invention can be achieved by using suitable mixing equipment such as a kneading mixer, a Z-blade mixer, a two-roll mill (open mill), a three-roll mill, or a Haake mill.TM The process can be performed using a Rheomix OS Lab mixer, screw extruder, or twin-screw extruder. Alternatively, a high-speed mixer, such as those sold by Hauschild as DC 150.1FV, DAC 400FVZ, or DAC 600FVZ, can be used.

[0147] Curable silicone elastomer compositions can be processed (or cured) by injection molding, compression molding, extrusion, transfer molding, pressure vulcanization, and calendering.

[0148] Curing can occur, for example, in a mold to form a molded silicone article that adheres to, for example, a polycarbonate substrate. The curable silicone elastomer composition can be, for example, injection molded to form an article that adheres to a polycarbonate material, or the composition can be overmolded by injection molding around or on a thermoplastic substrate, an organic resin substrate, or a combination of thermoplastic and organic resin substrates or articles. When cured in the presence of a heat-sensitive substrate, the curable silicone elastomer composition described below is cured under conditions that enable mechanical adhesion to the heat-sensitive substrate, etc., and more specifically, by using a temperature and curing time that prevents the heat-sensitive substrate from deforming, melting, or degenerating.

[0149] Curable silicone elastomer compositions can be cured into silicone elastomer articles that adhere to thermoplastic substrates, organic resin substrates, or a combination of thermoplastic and organic resin substrates, such as tubes, strips, solid ropes, or custom profiles to the manufacturer’s size specifications.

[0150] The curable silicone elastomer composition described above can be applied to the surface of a substrate by any suitable method, such as rolling, spreading, 3D printing, etc., and cured as described above. After the curable silicone elastomer composition is applied to the substrate, the composition is cured at a curing temperature ranging from 80°C to 250°C. Such temperatures are typically determined by the materials involved. In the case of 3D printing, the 3D printer can be selected from fused filament manufacturing printers, selective laser sintering printers, selective laser melting printers, stereolithography printers, powder bed (binder jet) printers, material jet printers, direct metal laser sintering printers, electron beam melting printers, laminated article manufacturing deposition printers, directional energy deposition printers, laser powder forming printers, polymer jet printers, inkjet printers, material jet printers, and syringe extrusion printers.

[0151] In one embodiment, this document provides an article comprising a silicone elastomer cured from a curable silicone elastomer composition as described above, or a silicone elastomer cured from a curable silicone elastomer composition on a rigid or flexible substrate such as the type described above.

[0152] In another embodiment, a composite component is provided comprising a silicone elastomer cured on a rigid or flexible substrate by a curable silicone elastomer composition as described above. It should be understood that such composite components include those constructions in which either the substrate or the silicone elastomer serves as an integral part in an article of manufacture. An example of a substrate as described above.

[0153] In one embodiment, an article or composite component comprising an elastomeric material is provided, the elastomeric material being produced by adhering the aforementioned curable silicone elastomer composition to a thermoplastic substrate, an organic resin substrate, or a thermoplastic and organic resin substrate as described above.

[0154] In another embodiment, the curable silicone elastomer composition as described above can be applied to the surface of a substrate processed using a 3D printing method. Typical methods for forming three-dimensional (3D) articles may include multiple steps. For example, the method may include (i) providing a thermoplastic substrate, an organic resin substrate, or a combination of thermoplastic and organic resin substrates. The method may also include (ii) heating the substrate. Additionally, the method may include (iii) printing the curable silicone elastomer composition as described above using a 3D printer to form subsequent layers. Optionally, if one or more additional layers are required, the latter step may be repeated.

[0155] Examples of such articles or composite components can be found in various industries, including but not limited to automotive, medical, consumer and industrial, and electronic applications. In automotive applications, this may include housings with silicone seals or gaskets, plugs and connectors, components of various sensors, membranes, diaphragms, climate control components, etc. Electronic applications may include mobile phone cover seals, mobile phone accessories, precision electronic equipment, electronic switches and switch covers, watches and wristbands, wearable devices (e.g., face masks), wearable electronic devices, etc.; mobile communication devices, game consoles, clocks, image receivers, DVD devices, MD devices, CD devices, and other precision electronic equipment; microwave ovens, refrigerators, rice cookers, thin displays for TVs, LCD TVs and plasma TVs, various household appliances, copiers, printers, fax machines and other office automation (OA) equipment, connector seals, spark plug caps, components of various sensors, and other automotive parts. Example

[0156] Unless otherwise stated, all viscosities in the following examples were measured using a rheometer, such as an Anton-Paar MCR-301 rheometer fitted with a 25 mm cone plate clamp and operated at 25°C. Unless otherwise stated, viscosities are reported as 0-shear viscosities, meaning values ​​extrapolated from the statistically significant, rate-independent Newtonian region of the viscosity versus shear rate scan to the 0-shear rate. The weight percent (wt%) of vinyl and Si-H were determined using quantitative infrared analysis according to ASTM E168. In the first series of examples, a reference example and three examples are provided using compositions containing the following components:

[0157] Table 1 - Ingredients

[0158]

[0159] The packing material used in the treatment was manufactured by Cabot Corporation under the trade name CAB-O-SIL. TM S-17D sells pyrolytic silica treated with hexamethyldisilazane (HMDZ) and tetramethyldivinyldisilazane.

[0160] Four alternative tackifiers were used in the following first series of examples. They were prepared according to the method described in PCT / US20 / 044709, disclosed as WO 2021 / 0260055:

[0161] Tackifier 1: ViR 4 2SiO-(R 5 2SiO) m -SiR 4 The reaction product of 2Vi with maleic anhydride (MAH) and AH and benzoyl peroxide (BPO) in m-xylene, wherein R 4 and R 5 It is methyl and the average value of m is 177. The product has a vinyl equivalent of 9600 (g / mol Vi) and an anhydride equivalent of 22,000 (g / mol anhydride).

[0162] Tackifier 2ViR 4 2SiO-(R 5 2SiO) m -SiR 4 The reaction product of 2Vi with maleic anhydride and benzoyl peroxide (BPO) in m-xylene, wherein R 4 and R 5 It is methyl and the average value of m is 46. The resulting product has a vinyl equivalent of 3700 (g / mol Vi) and an anhydride equivalent of 3900 (g / mol anhydride).

[0163] 3ViR tackifier 4 2SiO-(R 5 2SiO) m -SiR 4 The reaction product of 2Vi with maleic anhydride and benzoyl peroxide (BPO) in m-xylene, wherein R 4 and R 5 It is methyl and the average value of m is 7. The resulting product has a vinyl equivalent of 1000 (g / mol Vi) and an anhydride equivalent of 860 (g / mol anhydride).

[0164] Tackifier 4 is another example of using the starting components determined for tackifier 3 but using a lower ratio than that used for additive 3, with an equivalent weight (g / mol Vi) of 590 for vinyl and an equivalent weight (g / mol anhydride) of 1400 for anhydride.

[0165] In the above, the estimated value of the average value of m is determined by the number-average molecular weight (Mn) of the polymer peak obtained by GPC in a solvent such as toluene, calibrated with polystyrene standards, using the following formula:

[0166] n=[Mn–2*FW(M(R 4 2Vi))] / FW(D(R 5 2))

[0167] Where FW represents the formula weight of the structural group in parentheses, and Mn and all FW are reported in g / mol. For example, for structure M Vi -D n -M Vi Vinyl-terminated PDMS

[0168] n = [Mn – 2*(93.202)] / 74.16

[0169] The equivalent weight of vinyl groups (EW(Vi)) is again determined by the number-average molecular weight (Mn) of the polymer peak obtained by GPC in a solvent such as toluene, using the following formula, which is calibrated with polystyrene standards:

[0170] EW(Vi)=Mn / (v+y)

[0171] The equivalent weight of the acid anhydride (EW(anh)) is given as follows: EW(anh) = Mn / (x+z)

[0172] The seven different compositions evaluated were prepared by preparing a portion of composition A, then preparing a portion of composition B, and subsequently mixing the portions of composition A and composition B in a 1:1 weight ratio.

[0173] Table 2. Part A composition (wt%)

[0174]

[0175]

[0176] Tackifiers 1 and 2 were added directly to part A. Tackifiers 3 and 4 were found to be solids and therefore dissolved in an equal volume of acetone, which was then mixed into the composition of part A. The acetone was then evaporated.

[0177] Using Flacktek To prepare part A of the composition, add the ingredients to a polypropylene dental cup, then mix the mixture at 2000 rpm for 20 seconds, followed by manual scraping and mixing. Mix the sample again at 2000 rpm for 20 seconds, then manually scrape and mix, and finally mix for a final 20 seconds at 2000 rpm.

[0178] Table 3. Part B composition (wt%)

[0179] Component Reference 1 Example 1 Example 2 Example 3 Polymer 1 61.23 60.55 60.80 60.48 Polymer 2 1.53 1.51 1.52 1.51 Crosslinker 1 1.99 1.97 1.98 1.97 Crosslinker 2 1.10 0.69 1.22 Polymer 4 1.02 1.01 1.01 1.00 Treated filler 31.89 31.54 31.67 31.50 Inhibitor 2.34 2.32 2.33 2.31

[0180] Part B is mixed using a similar mixing scheme as that used for part A. Part A and part B are then mixed together in a 1:1 weight ratio.

[0181] Different compositions prepared by mixing a portion of composition A and a portion of composition B together are applied to two substrates.

[0182] Substrate 1 (S.1) is manufactured by BASF under the trade name Ultradur. TM The B4300G4 sold polybutylene terephthalate (PBT) (20% glass fiber); and

[0183] In each case, the corresponding substrate was wiped with isopropyl alcohol (IPA) and air-dried before applying the prepared composition. In each case, the prepared composition was then applied to the substrate to a thickness of 25 mils (0.0635 cm). Subsequently, the silicone composition was cured in a forced-ventilation oven at 150°C for 1 hour. Using a razor blade, two vertical lines, separated by approximately the width of the scraper blade, were etched down across the width of the substrate and through the depth of the cured material to the substrate surface. Force was manually applied to the material between the cuts by pressing the scraper at an angle of approximately 30° relative to the substrate surface. Adhesion (or lack thereof) was then subjectively evaluated.

[0184] Table 4. Results of properties tested

[0185] Mmol anhydride / 100 g total formulation Mmol anhydride / 100 g total matrix Adhesion on S.1 Reference 1 -- -- - Example 1 2.56 3.53 + Example 2 2.32 3.30 + Example 3 1.43 2.02 +

[0186] To avoid ambiguity in the tables above and below, when referring to the total composition, this is relative to each component shown in the ingredient list. When referring to the matrix, the unfilled composition (total composition minus treated filler) is discussed.

[0187] In Table 4, (-) poor adhesion = adhesion failure (separation from the substrate) and (+) moderate to good adhesion = mixed mode failure [cohesive failure (elastomer tearing) and adhesion failure].

[0188] The table above shows the significant effect of anhydride-grafted additives in the compositions of the present invention relative to those that do not have sufficient levels of anhydride functionality. Note that additives with low anhydride content (or higher equivalents of anhydride EWanh) will require considerably higher concentrations (in weight percent) to be effective. For example, thickener 1 (EWanh = 22,000 g / mol) requires a much higher concentration in LSR formulations than thickener 2 (EWanh = 3,900 g / mol) and thickener 3 (EWanh = 860 g / mol) (exceeding the tested concentrations) to be effective as a thickener in that formulation.

[0189] A second series of examples were produced using alternative compositions. Previously unidentified components are shown in Table 5 below, and the compositions themselves are depicted in Table 6.

[0190] Table 5. Additional ingredients not used in previous examples

[0191]

[0192]

[0193] In this case, the tackifier 1 described above is used as a tackifier and is combined with the corresponding polymeric starting material used to prepare tackifier 1, namely ViMe2SiO[Me2SiO] with a viscosity of about 443 mPa·s. 177 A comparison was made with SiMe2Vi (hereinafter referred to as an anhydride-free additive). Particle size information for fillers 1, 2, and 3 was obtained from the supplier's datasheet.

[0194] The following table lists the sample formulations for Part I, showing the grams (g) of each component (Table 3) and the anhydride concentration (mmol) calculated per 100g of total formulation and matrix components (Table 4).

[0195] Table 6. Formulation of conductive formulation reference 2, C.1, 2 and examples 4 to 7

[0196] Reference 2 C.1 C.2 Example 4 Example 5 Example 6 Example 7 Adhesion promoter (AP) None 2 1 1 1 1 1 AP (g) 0 0.4 0.04 0.2 0.4 0.6 0.8 AP (wt%) 0 1.0 0.1 0.5 1.0 1.5 2.0 Polymer 1 (g) 5.11 4.858 5.084 4.984 4.858 4.732 4.607 Polymer 2 (g) 1.278 1.215 1.271 1.246 1.215 1.183 1.152 Silane 1 (g) 0.406 0.386 0.404 0.396 0.386 0.376 0.366 Silane 2 (g) 0.041 0.039 0.041 0.04 0.039 0.038 0.037 Crosslinker (g) 0.573 0.545 0.57 0.559 0.545 0.531 0.516 Inhibitor (g) 0.445 0.423 0.443 0.434 0.423 0.412 0.401 Catalyst (g) 0.276 0.262 0.275 0.269 0.262 0.256 0.249 Filler 1 (g) 3.822 3.822 3.822 3.822 3.822 3.822 3.822 Filler 2 (g) 19.11 19.11 19.11 19.11 19.11 19.11 19.11 Filler 3 (g) 8.941 8.941 8.941 8.941 8.941 8.941 8.941

[0197] Sample preparation: In a dental cup, "Inhibitor Solution 1" and "Catalyst Solution 1" were prepared as shown below:

[0198] Inhibitor solution 1

[0199] Sample 1 of inhibitor solution was prepared by first adding 2.00 g of inhibitor 1, followed by 18.00 g of polymer 2, in a dental cup. The added components were then mixed at 2000 rpm for 30 seconds.

[0200] Catalyst solution 1

[0201] A sample of catalyst solution 1 was prepared in a dental cup by first adding 2.00 g of platinum catalyst 1, followed by 18.00 g of polymer 2. The added components were then mixed at 200 rpm for 30 seconds.

[0202] Preparation of formulations

[0203] In a dental cup, add the required amounts of Polymer 1, Polymer 2, Additive 1 or 2 (where applicable), Silane 1, Silane 2, and Filler 1. Gently mix manually and dentally at 1600 rpm for 30 seconds each time. Add Filler 2. Gently mix manually and dentally at 1600 rpm for 30 seconds each time. Add Filler 3. Gently mix manually and dentally at 1600 rpm twice for 30 seconds each time. Add the required amounts of Inhibitor Solution 1 and Crosslinking Agent 1. Gently mix manually and dentally at 1600 rpm for 30 seconds each time. Add the required amount of Catalyst Solution 1. Gently mix manually and dentally at 1600 rpm for 30 seconds each time to obtain the final sample.

[0204] Table 7. Calculation of mmol of anhydride relative to matrix components in the total formulation using calculations as described below .

[0205]

[0206]

[0207] Description of mmol acid anhydride calculation: mmol acid anhydride is calculated by dividing the number of grams of anhydride-grafted additive (e.g., maleic anhydride-grafted additive) in 100g of formulation or 100g of matrix component (unfilled) itself (as shown in the table) by 22000g / mol (for additive 1), and then multiplying it by 1000.

[0208] A fluorinated polyester anti-stick pad (3M) will be placed on another membrane. TM9956 Medical anti-adhesive liner (polyester, fluoropolymer) was used as the substrate for curing a sample between two substrates, with the polyester side of the substrate exposed to the sample. Each composition in Table 6 above was applied to the substrate surface, and the interlayer material was cured at 150°C for 1 hour. Relative adhesive strength was evaluated by determining whether cohesive failure occurred due to a peel test. Results showed that the control formulation without additive 1 (Reference 1), the formulation with additives without anhydride functional groups (Additive 2, C.1), and the formulation containing 0.1 wt% of additive 1 (C.22) exhibited adhesive failure. Formulations containing 0.5 to 2 wt% of additive 1 showed cohesive failure, indicating improved relative adhesion to the substrate. This surprising result facilitated the use of LSR in previous embodiments, demonstrating that the use of component (D) as described herein can improve adhesion to plastics and other substrates. These embodiments show that this can also be achieved using filled siloxane systems, such as conductive composites.

[0209] Peel tests were performed on cured samples at room temperature by manually peeling two sheets apart to determine whether this caused cohesive failure.

Claims

1. A curable silicone elastomer composition capable of achieving adhesion to a material substrate and comprising: (A) one or more organopolysiloxanes containing at least two unsaturated groups per molecule selected from the group consisting of alkenyl groups and alkynyl groups, and having a viscosity at 25 °C in the range of 1000 mPa.s to 500,000 mPa.s, but not containing anhydride functionality; (B) a curing agent comprising (B)(i) an organic peroxide radical initiator; or (B)(ii) a hydrosilylation cure catalyst comprising a. an organosilicon compound having at least two, alternatively at least three, Si-H groups per molecule; and b. a hydrosilylation catalyst; (C) at least one reinforcing filler and optionally one or more non-reinforcing fillers; and (D) a polyorganosiloxane having (i) at least one unsaturated group per molecule selected from the group consisting of alkenyl groups and alkynyl groups, and (ii) an anhydride functionality and an aromatic functionality, wherein the carbon of the aromatic functionality is separated from the carbon of the carbonyl of the anhydride by a carbon chain of 1 to 3 non-aromatic carbon atoms, inclusive.

2. The curable silicone elastomer composition of claim 1, wherein component (D) comprises a monofunctionalized polyorganosiloxane of the formula: wherein X is an aromatic group, and wherein each molecule contains at least one alkenyl or alkynyl group. ViR 4 2SiO-(R 5 2SiO) m -SiR 4 2A’ or A' R 4 2 SiO- (R 5 2 SiO) m -SiR 4 2 A' wherein Vi refers to a vinyl group, each R 4 is an alkyl group, each R 5 is an alkyl group, an alkenyl group, an alkynyl group, or A', and A' is:

3. The curable silicone elastomer composition of claim 2, wherein in component (D) X is a benzoyl group, a tolyl group, or a xylyl group.

4. The curable silicone elastomer composition of claim 1, 2, or 3, wherein component (D) is added to the composition in an amount of 0.5% to 5% by weight of the total composition of the other ingredients.

5. The curable silicone elastomer composition of claim 1, 2, or 3, wherein the composition comprises a cure inhibitor.

6. The curable silicone elastomer composition of claim 1, 2, or 3, which is stored in at least 2 separate parts prior to use.

7. A method for making an article or a composite part of an article, the method comprising: a) forming a mixture of the curable silicone elastomer composition of claim 1, and b) applying the mixture to a surface of a substrate; c) curing the mixture at a temperature of 80 °C to 250 °C.

8. The method of claim 7, wherein the substrate is polycarbonate.

9. An article cured from the curable silicone elastomer composition of claim 1.

10. The article of claim 9, containing a silicone elastomer cured from the curable silicone elastomer composition of any one of claims 1 to 6 adhered to a plastic substrate. ​ 11. The article according to claim 9, which contains a silicone elastomer cured from the curable silicone elastomer composition according to claim 1 adhered to a thermoplastic plastic base, an organic resin base, or a thermoplastic plastic and an organic resin base.

12. The article according to claim 9 or 10, which is selected from the group consisting of housings with silicone seals or gaskets, plugs and connectors, components of various sensors, membranes, climate vent components, precision electronic devices, electrical switches and switch covers, watches or wristbands.

13. A composite component comprising a silicone elastomer cured from the curable silicone elastomer composition according to claim 1 on a plastic or resin material base.

14. The composite component according to claim 13, which is selected from the group consisting of housings with silicone seals or gaskets, plugs and connectors, membranes, climate vent components, personal electronic devices, various household appliances, copiers, printers, facsimile machines, connector seals, spark plug caps, and components of various sensors.

15. Use of the composition according to claim 1, 2 or 3 for the manufacture of an article comprising a cured elastomer material made from the composition adhered to a material base; and a method for adhering the composition to a thermoplastic plastic or organic resin based base.

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