KR20070036090A - Elastomer silicone vulcanizates - Google Patents

Abstract

Elastomer (A),

Optional compatibilizer (B),

Any catalyst (C),

Silicone base material (D) containing curable organopolysiloxane,

Optional crosslinker (E) and

Mixing (I) an amount of curing agent (F) sufficient to cure the organopolysiloxane; and

Described is a process for preparing an elastomeric composition, wherein the weight ratio range of elastomer (A) to silicone substrate (D) is 95: 5 to 30:70, comprising statically vulcanizing the organopolysiloxane. It is.

The elastomer composition obtained by the process of the present invention and the cured elastomeric composition prepared therefrom are excellent in low temperature and high temperature properties.

Elastomers, Compatibilizers, Catalysts, Curable Organopolysiloxanes, Silicone Substrate (D), Crosslinkers, Curing Agents, Elastomeric Compositions

Description

Elastomer silicone vulcanizates

Explanation

Cross Reference to Related Application

This application claims priority to US Patent Application No. 60 / 584,306, filed June 30, 2004.

Field of invention

The present invention relates to a process for preparing an elastomeric composition comprising silicon and another elastomer based on a static vulcanization process of silicon. The invention further relates to products produced by the process and cured elastomeric compositions obtained therefrom.

Background of the Invention

Silicone rubbers are characterized by excellent high and low temperature properties, weather resistance and processing properties. There is a need to modify guitar elastomers in a way that is effective to improve the performance of other elastomers at extreme temperatures. In particular, where high and / or low temperature properties are required, there is a need to provide elastomeric compositions for use in various applications. There is also a need to modify it in a way that is effective to improve the processing of the elastomer.

Relatively few attempts have been made to provide elastomers modified by the addition or blending of polymers based on siloxanes. Stable homogeneous mixtures are difficult to obtain due to incompatibility with elastomers and polymers based on these siloxanes. In addition, the blend should be cocrosslinkable. Some examples for providing elastomers and silicone rubber compositions include US Pat. Nos. 4,942,202, 5,010,137, 5,171,787, and 5,350,804.

US Patent No. 4,942,202 discloses rubber compositions and vulcanized rubber products. The '202 composition comprises silicone rubber (I) under shear deformation of organic peroxides, saturated elastomers (II), which, when used alone, do not react with organic peroxides and additional elastomers capable of cocrosslinking with silicone rubbers in the presence of organic peroxides (III). It is prepared by reacting with). Other elastomers (III) are also co-crosslinkable or very miscible with component (II).

US Patent No. 5,010,137 discloses rubber compositions comprising elastomers and oil seals and rubber hoses obtained therefrom. The '137 composition blends a polyorganohydrogensiloxane and group VIII transition metal compound with a rubber forming polymer comprising vinyl containing polyorganosiloxane (I) and organic rubber (II) and incorporates the compounds produced during the shearing deformation. Obtained by hydrosilylation.

U. S. Patent No. 5,171, 787 describes a composite rubber composition based on silicone and its use. The '787 composition catalyzes rubber forming polymers (A) comprising polyorganosiloxanes and organic rubbers, silicon compounds (B) having two or more hydrolyzable groups per molecule, and heavy metal compounds, amines, or hydrolysis and condensation reactions. Quaternary ammonium salt (C) is formulated, and the resulting formulation is subjected to hydrolysis and condensation reaction while the formulation remains deformed by shear, crosslinking agent is subsequently added, and then the organic rubber is crosslinked. By combining.

U.S. Patent No. 5,350,804 discloses an organic rubber elastomer composition (a) having a Mooney viscosity of at least 70, forming a matrix phase of a composite rubber composition, and a cured silicone rubber as a phase dispersed on a matrix ( A composite rubber composition comprising b) is disclosed.

While these patents provide advances in the art, there is still a need to specifically modify elastomers in a manner that is effective to provide low cost, high performance elastomeric systems while maintaining the original physical properties of such systems. In particular, where high or low temperature properties as well as resistance to fuels, oils, exhaust gases or chemicals are required, there is a need to provide elastomeric compositions for use in various applications.

The present invention provides an elastomeric composition based on the incorporation of silicone and other elastomers using a static vulcanization process. Such elastomeric compositions result from the novel mixing process of the present invention. This novel mixing process provides a composition having a composition based on a significant amount of silicone rubber incorporated into another elastomer. However, the resulting cured elastomeric compositions made from the elastomeric compositions of the present invention retain many of the desirable physical properties of the elastomers.

Summary of the Invention

The present invention provides a method of making an elastomeric composition comprising both elastomer and silicone, wherein the silicone substrate is mixed with another elastomer and the silicone substrate is subsequently statically vulcanized in the elastomer.

Therefore, the present invention

Elastomer (A),

Optional compatibilizer (B),

Any catalyst (C),

Silicone base material (D) containing curable organopolysiloxane,

Optional crosslinker (E) and

Mixing (I) an amount of curing agent (F) sufficient to cure the organopolysiloxane; and

A method for preparing an elastomeric composition, wherein the weight ratio range of the elastomer (A) to the silicone base (D) is 95: 5 to 30:70, comprising statically vulcanizing the organopolysiloxane. will be.

The present invention further relates to elastomeric compositions obtained by the process and to cured elastomeric compositions prepared therefrom.

Detailed Description of the Preferred Embodiments

Component (A) is an elastomer having a glass transition temperature (Tg) of no greater than room temperature, alternatively no greater than 23 ° C, alternatively no greater than 15 ° C, alternatively no greater than 0 ° C. "Glass transition temperature" means the temperature at which a polymer changes from a glassy state to a rubbery state. Glass transition temperatures can be measured by conventional methods such as mechanical mechanical analysis (DMA) and differential scanning calorimetry (DSC). As used herein, "elastomer" excludes elastomers based on known silicones, such as silicone rubber. Elastomeric component (A) is known in the art as natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), butadiene rubber (BR), chloroprene rubber (CR), chlorinated polyethylene (CPE), butyl rubber , Acrylonitrile-butadiene rubber (NBR), chlorosulfonated ethylene (CSM), acrylic rubber (ACM), epichlorohydrin rubber (ECO), ethylene-vinyl acetate rubber (EVM), ethylene-acrylic rubber, ethylene Major classes of elastomers and rubbers known as -α-olefin copolymer rubbers, ethylene-α-olefin-diene terpolymer rubbers (EPDM), carbon fluorocarbon elastomers (FKM) and hydrogenated nitrile rubbers (HNBR) (ASTM nomenclature are in parentheses). May be selected).

Alternatively, the elastomer is a high performance elastomer selected from chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CPE / CM), ethylene-vinyl acetate rubber (EVM), epichlorohydrin rubber (ECO) and acrylic rubber (ACM). Alternatively, the elastomer is selected from ethylene-α-olefin-diene terpolymer rubber (EPDM), hydrogenated nitrile rubber (HNBR), and fluorocarbon elastomers (FKM).

In the chemically modified elastomer embodiments described below, (A) is selected from elastomers comprising polymers capable of reacting the compatibilizer (B) with any catalyst (C) to produce the modified elastomer. While not wishing to be bound by any theory, the inventors, as a component (A), provide that, in a chemically modified embodiment, any elastomer or modified elastomer includes one or more groups capable of reacting with one or more portions of the silicone substrate. I believe it can be chosen. Alternatively, the elastomer should be able to react with the silicone substrate through the functional curing mechanism selected for the organopolysiloxane. The curing agent (F) is added to the organopolysiloxane (D) and any crosslinking agent (E) to cure the organopolysiloxane via a static vulcanization process. Typically, during the static vulcanization process, ie step (II), the curing chemicals occurring on the surface of the silicone compound can also react with the elastomer, which promotes the dispersion of the silicon in the elastomer. Representative non-limiting examples of reactive groups in the elastomer include methyl, methylene, vinyl and halogen. For example, methyl or methylene groups in the elastomer can react with a peroxide selected as a curing agent for the silicone compound to form a bond between the organopolysiloxane and the elastomer. As another example, the vinyl groups in the elastomer can be reacted via an addition cure mechanism or a radical cure mechanism.

It is contemplated that the elastomer (A) may be a mixture of polymers. However, in a chemically modified elastomer embodiment, at least 2%, alternatively at least 5%, or alternatively at least 10% by weight of the elastomeric composition has a polymer having a reactive group capable of reacting with the curing chemical of the organopolysiloxane. Must include.

Any compatibilizer (B) is expected to modify the elastomer in such a way as to increase the mixing of the silicone substrate (D) and the elastomer (A) to produce a mixture having a continuous elastomeric phase and a discontinuous (ie internal phase) silicone phase. Can be selected from any hydrocarbon, organosiloxane, carbon fluoride or mixtures thereof. In general, the compatibilizer may be one of two types. In a first aspect herein relating to a physical compatibilizer, it is selected from any hydrocarbon, organosiloxane, carbon fluoride or mixtures thereof, which will react with the elastomer (A) and still increase the mixture of the elastomer with the silicone substrate. It is not expected. In a second aspect herein relating to a chemical compatibilizer, the chemical compatibilizer is selected from any hydrocarbon, organosiloxane, fluorocarbon, or mixtures thereof, which can chemically react with the elastomer and / or silicone rubber. However, in another embodiment, the chemical compatibilizer should not inhibit static cure of the organopolysiloxane component described below.

In a physically modified embodiment, the compatibilizer (B) can be selected from any compatibilizer known in the art to increase the mixture of the silicone substrate with the elastomer.

In chemically modified embodiments, the compatibilizer (B) typically comprises an organic (ie non-silicone) compound (B ¹ ) comprising two or more olefin groups, an organopolysiloxane comprising two or more alkenyl groups ( B ² ), olefin functional silanes comprising one or more hydrolyzable groups or one or more hydroxyl groups bonded to silicon atoms (B ³ ), amines, amides, isocyanurates, phenols, acrylates, epoxies and thiols Organopolysiloxane (B ⁴ ), dehydrofluorinating agent (B ⁵ ), and component (B ¹ ), component (B ² ), component (B ³ ), component (B ⁴ ) having at least one organic functional group selected from the group ) And any combination of component (B ⁵ ).

Organic compatibilizers (B ') are in particular diallylphthalate, triallyl isocyanurate, 2,4,6-triallyloxy-1,3,5-triazine, triallyl trimesate, 1,5-hexa Compounds such as dienes, low molecular weight polybutadiene, 1,7-octadiene, 2,2'-diallylbisphenol A, N, N'-diallyl tartadiamide, diallylurea, diallyl succinate and divinyl sulfone It can be illustrated as.

The compatibilizer (B ″) may be selected from straight chain, branched or cyclic organopolysiloxanes having two or more alkenyl groups in the molecule. Examples of such organopolysiloxanes are divinyltetramethyldisiloxane, cyclotrimethyltrivinyl Trisiloxane, cyclo-tetramethyltetravinyltetrasiloxane, hydroxy end blocked polymethylvinylsiloxane, hydroxy terminated polymethylvinylsiloxane-copolydimethylsiloxane, dimethylvinylsiloxy terminated polydimethylsiloxane, tetrakis (dimethyl Vinylsiloxy) silane and tris (dimethylvinylsiloxy) phenylsilane. Alternatively, the compatibilizer (B ") has a viscosity of about 25 to 100 mPa-s and 20 to 35% vinyl group and silicon-bonded hydroxy. Hydroxy terminated polymethylvinylsiloxane [HO (MeViSiO) _x H] oligomers containing groups 2-4%.

The compatibilizer (B ′ ″) is a silane, which typically comprises one or more alkylene groups, including one or more silicon-bonded moieties selected from hydrolyzable groups or hydroxyl groups, as well as vinyl unsaturations. Suitable hydrolyzable groups Include alkoxy, aryloxy, acyloxy or amido groups Examples of such silanes include vinyltriethoxysilane, vinyltrimethoxysilane, hexenyltriethoxysilane, hexenyltrimethoxy, methylvinyldisilane Ol, octenyltriethoxysilane, vinyltriacetoxysilane, vinyltris (2-ethoxyethoxy) silane, methylvinylbis (N-methylacetamido) silane, and methylvinyldisilanol.

Compatibilizers (B "") are organopolysiloxanes having at least one organic functional group selected from amine, amide, isocyanurate, phenol, acrylate, epoxy and thiol groups.

It is possible that portions of the curable organopolysiloxane of the silicone based component (D) described below can also act as compatibilizers. For example, the catalyst (C) may first be used to prepare a modified elastomer by reacting the elastomer with the curable organopolysiloxane portion of the silicone substrate (D). The modified elastomer is further mixed with the remaining silicone base (D) comprising the curable organopolysiloxane, and the organopolysiloxane is statically vulcanized as described below.

The amount of compatibilizer used per 100 parts of elastomer can be measured by routine experiments. Typically, 0.05 to 15 parts by weight, alternatively 0.05 to 10 parts by weight, or alternatively 0.1 to 5 parts by weight, are used per 100 parts by weight of each of the elastomers (A).

Optional component (C) is a catalyst. Typically, catalysts are used in chemically modified embodiments. As such, it is typically a radical initiator selected from any organic compound, which is known in the art to generate free radicals at elevated temperatures. The initiator is not particularly limited and may be any one of known azo or diazo compounds, for example 2,2'-azobisisobutyronitrile, but is preferably an organic peroxide such as hydroper Oxides, diacyl peroxides, ketone peroxides, peroxyesters, dialkyl peroxides, peroxydicarbonates, peroxyketals, peroxy acids, acyl alkylsulfonyl peroxides and alkylmonoperoxydicarbonates. An important requirement, however, is that the half-life of the initiator is short enough to facilitate the reaction of the compatibilizer (B) with the elastomer (A) within the time and temperature constraints of step (i). In turn, the change temperature depends on the type of elastomer and compatibilizer selected and is typically as low as substantially consistent with the homogeneous mixing of components (A) to (C). Specific examples of suitable peroxides that may be used according to the process of the invention include 2,4-dimethyl-2,5-di (tert butylperoxy) hexane; Benzoyl peroxide; Dicumyl peroxide, tertiary butyl peroxy O-toluate; Cyclic peroxykenal; Tertiary butyl hydroperoxide; Tert butyl peroxypivalate; Lauroyl peroxide; Tertiary amyl peroxy 2-ethylhexanoate; Vinyltris (tert butyl peroxy) silane; Di-tertiary butyl peroxide; 1,3-bis (tert butylperoxyisopropyl) benzene; 2,2 4-trimethylpentyl-2-hydroperoxide; 2,5-bis (tert butylperoxy) -2,5-dimethylhexine-3, tertiary butyl-peroxy-3,5,5-dimethylhexanoate; Cumene hydroperoxide; Tertiary butyl peroxybenzoate and diisopropylbenzene mono hydroperoxide. Less than 2 parts by weight of peroxide per 100 parts by weight of elastomer is typically used. Alternatively, 0.05 to 1 parts by weight and 0.2 to 0.7 parts by weight may also be used.

Component (D) is a silicone base comprising curable organopolysiloxane (D ′) and optional filler (D ″). Curable organopolysiloxane is herein an organo with any two or more curable groups present in the molecule. is defined as the polysiloxane. organopolysiloxane _{(R 3 SiO 0 .5),} D units (R ₂ SiO), T units (RSiO _{1 .5)} or Q unit (SiO well are known, commonly unit M in the art ₂ ), wherein R is independently any monovalent hydrocarbon group .. Alternatively, organopolysiloxanes are often represented by the formula [R _m Si (O) _{4-m / 2} ] _{It is described as having n} (wherein R is independently any monovalent hydrocarbon group, m is 1-3 and n is at least 2).

The organopolysiloxane in the silicone base (D) should have at least two curable groups in the molecule. As used herein, a curable group is defined as any hydrocarbon group that can react with itself or with additional hydrocarbon groups, or alternatively can react with a crosslinker to crosslink the organopolysiloxane. Such crosslinks are formed in the cured organopolysiloxane. Representative types of curable organopolysiloxanes that can be used in silicone substrates are organopolysiloxanes known in the art to produce silicone rubber upon curing. Representative non-limiting examples of such organopolysiloxanes are described in "Encyclopedia of Chemical Technology", by Kirk-Othmer, 4th Edition, Vol. 22, pages 82-142, John Wiley & Sons, NY. Typically, organopolysiloxanes can be cured through a number of crosslinking mechanisms using various curing groups for organopolysiloxanes, curing agents, and any crosslinking agent. Although many crosslinking mechanisms exist, three of the additional common crosslinking mechanisms used in the art for making silicone rubber from curable organopolysiloxanes are free radical initiated crosslinking, hydrosilylation or addition curing and condensation curing. to be. Thus, the curable organopolysiloxane can be selected from any organopolysiloxane capable of performing any of these above-mentioned crosslinking mechanisms, although not limited thereto. The selection of components (D), (E) and (F) is made consistent with the selection of the curing or crosslinking mechanism. For example, when hydrosilylation or addition cure is selected, silicone substrates comprising organopolysiloxanes having two or more vinyl groups (curable groups) are used as component (D ′) and organic hydrido silicon compounds Silver is used as component (E) and platinum catalyst is used as component (F). In the case of condensation cure, silicone substrates comprising organopolysiloxanes having two or more silicon-bonded hydroxy groups (ie silanol, believed to be curable groups) are selected as component (D) and are known in the art as condensation cure. The catalyst, for example tin catalyst, is selected as component (F). In the case of free radical initiated crosslinking, any organopolysiloxane can be selected as component (D) and the free radical initiator can be selected from component (F) if the formulation is cured within the time and temperature constraints of the static vulcanization step (II). ) Is selected. Depending on the choice of component (F) in such free radical initiated crosslinking, any alkyl group, for example methyl group, can be considered as a curable group because it is crosslinked under such free radical initiation conditions.

The amount of silicone phase as defined herein as the combination of component (D), component (E) and component (F) used may vary depending on the amount of elastomer (A) used.

It is convenient to report that the weight ratio range of elastomer (A) to silicone substrate (D) is typically 95: 5 to 30:70, alternatively 90:10 to 40:60, alternatively 80:20 to 40:60.

In the addition curing aspect of the present invention, the selection of components (D), (E) and (F) can be made to produce silicone rubber during the vulcanization process via hydrosilylation curing techniques. Such an embodiment is referred to herein as a hydrosilylation cure embodiment. Thus, in the hydrosilylation cure aspect (D '), (D') is selected from diorganopolysiloxane gums comprising two or more alkenyl groups having 2 to 20 carbon atoms and optionally (D "), reinforcing fillers. Alkenyl groups are specifically exemplified by vinyl, allyl, butenyl, pentenyl, hexenyl and desenyl, preferably vinyl or hexenyl The position of the alkenyl functionality is not critical and is at the molecular chain end, molecular chain Typically, the alkenyl group is vinyl or hexenyl, which group is present at a concentration of 0.0001 to 3 mole%, alternatively 0.0005 to 1 mole% in diorganopolysiloxane. Residual (ie, non-alkenyl) silicon-bonded organic groups of diorganopolysiloxanes are independently selected from hydrocarbon or halogenated hydrocarbon groups, which include aliphatic unsaturations. C) alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl and hexyl; cycloalkyl groups such as cyclohexyl and cycloheptyl; aryl groups having 6 to 12 carbon atoms, eg For example, phenyl, tolyl and xylyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl and phenylethyl; halogenated alkyl groups having 1 to 20 carbon atoms, such as 3,3,3-trifluoro Illustrative examples are propyl and chloromethyl, which of course it is understood that these groups have a glass temperature at which the diorganopolysiloxane is below room temperature and thus the cured polymer is selected to be elastomeric. Non-alkenyl silicon-bonded organic groups make up at least 85 mole%, alternatively at least 90 mole%, of the organic groups in the diorganopolysiloxane.

Thus, the polydiorganosiloxane (D ′) may be a homopolymer, a copolymer or a terpolymer comprising such organic groups. Examples include homopolymers containing dimethylsiloxy units, homopolymers containing 3,3,3-trifluoropropylmethylsiloxy units, air containing dimethylsiloxy units and phenylmethylsiloxy units. Copolymer comprising copolymer, dimethylsiloxy unit and 3,3,3-trifluoropropylmethylsiloxy unit, copolymer comprising dimethylsiloxy unit and diphenylsiloxy unit, and dimethylsiloxy unit, di Copolymers comprising phenylsiloxy units and phenylmethylsiloxy units. Molecular structure is also not critical and is exemplified by the straight chain structure and the partially branched straight chain structure, the straight chain system is the most typical.

Specific examples of diorganopolysiloxanes (D ′) include the following:

Trimethylsiloxy-terminated blocked dimethylsiloxane-methylvinylsiloxane copolymer; Trimethylsiloxy-terminally blocked methylphenylsiloxane-dimethylsiloxane-methylvinylsiloxane copolymer; Trimethylsiloxy-terminated blocked 3,3,3-trifluoropropylmethyl siloxane copolymer; Trimethylsiloxy-terminated blocked 3,3,3-trifluoropropylmethyl-methylvinylsiloxane copolymer; Dimethylvinylsiloxy-terminated blocked dimethylpolysiloxanes; Dimethylvinylsiloxy-terminated blocked dimethylsiloxane-methylvinylsiloxane copolymer; Dimethylvinylsiloxy-terminated blocked methylphenylpolysiloxane; Dimethylvinylsiloxy-terminally blocked methylphenylsiloxane-dimethylsiloxane-methylvinylsiloxane copolymer; And similar copolymers wherein at least one end group is dimethylhydroxysiloxy. Typical systems for low temperature applications are methylphenylsiloxane-dimethylsiloxane-methylvinylsiloxane copolymers and diphenylsiloxane-dimethylsiloxane-methylvinylsiloxane copolymers, especially when the molar content of dimethylsiloxane units is about 85-95%.

Organopolysiloxanes may also consist of a combination of two or more organopolysiloxanes. Alternatively, the diorganopolysiloxane (D ′) is a straight chain polydimethylsiloxane homopolymer, preferably each end of the molecule is terminated with a vinyl group, or is such a homopolymer, which is also one or more vinyl groups along the main chain. It includes.

For the purposes of the present invention, preferred diorganopolysiloxanes have a Williams plasticity number of about 30 as measured by the American Society for Testing and Materials (ASTM) Test Method 926. It is diorganopolysiloxane which has a molecular weight sufficient to provide above. There is no absolute upper limit to the plasticity of component (D '), but practical considerations of processability in conventional mixing instruments generally limit this value. Typically, the plasticity number should be 40 to 200, or alternatively 50 to 150.

Processes for the preparation of high viscosity unsaturated group containing diorganopolysiloxanes are well known and do not require detailed discussion herein.

Optional component (D ″) is any filler known to reinforce diorganopolysiloxane (D ′) and is preferably a finely divided thermally stable inorganic, eg, fumed having a specific surface area of at least about 50 m ² / g And precipitated forms of silica, silica aerogels and titanium dioxide Fumed forms of silica are typical reinforcing fillers based on high surface areas, which can be up to 450 m ² / g or alternatively, surface areas of 50 to 400 m ² /. g, or alternatively, fumed silica of 90 to 380 m ² / g may be used.The filler is about 5 to about 150 parts by weight, alternatively 10 to 100 parts by weight, or alternatively, for each 100 parts by weight of diorganopolysiloxane (D ′). It is added at a concentration of 15 to 70 parts by weight.

Fillers are typically treated to cause surface hydrophobicity, as is typically done in the field of silicone rubber. This can be accomplished by reacting silica with a liquid organosilicon compound comprising a silanol group or a hydrolyzable precursor thereof. Compounds that can be used as filling treatment agents, also called anti-creping agents or plasticizers in the field of silicone rubber, are low molecular weight liquid hydroxy- or alkoxy-terminated polydiorganosiloxanes, hexaorganodisiloxanes, cyclodimethylsila And ingredients such as hexaorganic disilazane.

Component (D) also typically includes, but is not limited to, antioxidants, crosslinking aids, processing agents, pigments, and other additives known in the art that do not conflict with step (II) described below. It may include other materials used.

In a hydrosilylation cure embodiment of the invention, compound (E) is an organic hydrido silicon compound (E ') to which it is added and crosslinked with diorganopolysiloxane (D'). The organic hydrido silicon compound is an organopolysiloxane comprising at least two silicon-bonded hydrogen atoms in each molecule that react with the alkenyl functional groups of component (D ′) during the static vulcanization step (II) of the process. Further (molecular weight) limitations should have at least about 0.1%, alternatively 0.2 to 2%, or alternatively 0.5 to 1.7% by weight of hydrogen to which component (E ') is bonded to silicon. Of course, those skilled in the art will appreciate that the functionality of the diorganopolysiloxane (D ') or component (E'), or both, to cure diorganopolysiloxanes (ie, the sum of these functionalities should exceed an average of 4). Expect to be. The position of the silicon-bonded hydrogen in component (E ') is not critical and can be bonded at the molecular chain end, the non-terminal position along the molecular chain, or both. The silicon-bonded organic group of component (E ') is independently selected from any of the saturated hydrocarbons or halogenated hydrocarbon groups mentioned above in connection with diorganopolysiloxane (D'), and includes preferred embodiments thereof. The molecular weight of component (E ′) is also not critical and is exemplified by straight chain, partially branched straight chain, branched, cyclic and network structure, network structure, straight chain polymers or copolymers are common. Of course, it is recognized that this component must be compatible with D '(ie, it is effective at the curing of diorganopolysiloxanes).

Component (E ') is illustrated by:

Low molecular weight siloxane, PhSi (OSiMe ₂ H) ₃ ; Trimethylsiloxy-terminated blocked methylhydridopolysiloxane; Trimethylsiloxy-terminated blocked dimethylsiloxane-methylhydridosiloxane copolymer; Dimethylhydridosiloxy-terminated blocked dimethylpolysiloxanes; Dimethylhydrogensiloxy-terminated blocked methylhydrogenpolysiloxane; Dimethylhydridosiloxy-terminated blocked dimethylsiloxane-methylhydridosiloxane copolymers; Cyclic methylhydrogenpolysiloxanes; Cyclic dimethylsiloxane-methylhydridosiloxane copolymers; Tetrakis (dimethylhydrogensiloxy) silane; SiO _4/2 si trimethylsiloxy comprising units-methyl hydrido siloxane polymer end block; (CH ₃₎ a silicone resin consisting of ₂ HSi0 _1/2 and Si0 _4/2 units; _{(CH 3) 2 HSi0 1/2,} (CH 3) 3 Si0 silicone resin consisting of a _1/2 and SiO _4/2 units; (CH _{3) 2} HSi0 silicone resin consisting of a _1/2 and _{CF 3 CH 2 CH 3 SiO 3/2} ; And _{(CH 3) 2 HSiO 1/} 2, (CH 3) 3 SiO 1/2, CH 3 Si0 3/2, PhSiO silicone resin (here consisting of _3/2, and SiO _4/2 units, Ph is the after Phenyl radicals).

Typical organic hydrido silicon compound is R ₃ SiO _1/2 or HR ₂ SiO _1/2 units (wherein, R is selected independently from a profile with an alkyl radical, a phenyl or a trifluoromethyl group having 1 to 20 carbon atoms, typically Methyl)) or a polymer or copolymer comprising RHSiO terminated. Also, typically, the viscosity at 25 ° C. of component (E ′) is about 0.5 to 3,000 mPa-s, alternatively 1 to 2000 mPa-s. Component (E ') typically has from 0.5 to 1.7% by weight of hydrogen bonded to silicon. Alternatively, component (E ′) is a polymer consisting essentially of methylhydridosiloxane units, or methyl and dimethylsiloxane units having a viscosity of from 1 to 2000 mPa-s at 25 ° C. with 0.5 to 1.7 weight percent hydrogen bonded to silicon. It is selected from copolymers consisting essentially of hydrodosiloxane units. Alternatively, component (E ') is selected from a copolymer or network structure comprising resin units. Copolymer or network structures units RSiO _3/2 units, or SiO _4, and includes a _{/ 2} units, and _{R 3 SiO 1/2, R 2 SiO} 2/2 and / or RSiO _3/2 units (wherein, R is hydrogen Or independently selected from alkyl radicals having 1 to 20 carbon atoms, phenyl or trifluoropropyl, typically methyl. R, which is effective as hydrogen, is understood to be selected such that component (E ′) typically has from 0.5 to 1.7% by weight of hydrogen bonded to silicon. In addition, typically the viscosity at 25 ° C. of component (E ′) is about 0.5-3,000 mPa-s, alternatively 1-2000 mPa-s. Component (E ') may also be a combination of two or more of the abovementioned systems.

The organic hydrido silicon compound (E ') is used at a concentration sufficient to cure diorganopolysiloxane (D') in the presence of component (F) described below. Typically, its content is adjusted such that the molar ratio of SiH to Si-alkenyl in component (D ′) is greater than one. Typically, this SiH / alkenyl ratio is about 50 or less, alternatively 1 to 20, or alternatively 1 to 12. Such SiH-functional materials are well known in the art and many are commercially available.

In the hydrosilylation cure embodiment of the present invention, component (F) is a hydrosilylation catalyst (F ′) that promotes cure of diorganopolysiloxanes. It is a platinum catalyst such as platinum black, platinum supported on silica, platinum supported on carbon, chloroplatinic acid, alcohol solution of chloroplatinic acid, platinum / olefin complex, platinum / alkenylsiloxane complex, platinum / beta-diketone Complexes, platinum / phosphine complexes, and the like; Rhodium catalysts such as rhodium chloride and rhodium chloride / di (n-butyl) sulfide complex and the like; And palladium catalysts such as palladium on carbon, palladium chloride and the like. Component (F ') is typically a catalyst based on platinum, such as chloroplatinic acid; Platinum dichloride; Platinum tetrachloride; A platinum complex catalyst prepared by reacting dichlorotetramethyldisiloxane and chloroplatinic acid diluted with dimethylvinylsiloxy endblocked polydimethylsiloxane, prepared according to US Pat. No. 3,419,593 to Willing; And neutralizing complexes of divinyltetramethyldisiloxane with platinum monochloride, prepared according to US Pat. No. 5,175,325 to Brown et al., Which are incorporated herein by reference. Alternatively, the catalyst (F) is a neutralization complex of divinyltetramethyldisiloxane and platinum chloride.

Component (F ') corresponds to a catalytic amount sufficient to catalyze the reaction of organopolysiloxane (D') with component (E ') to cure organopolysiloxane within the time and temperature limits of static vulcanization step (II). Is added to the composition. Typically, the hydrosilylation catalyst is added to provide about 0.1 to 500 ppm, alternatively 0.25 to 50 ppm of metal atoms, based on the total weight of the elastomeric composition.

In another embodiment, component (D), component (E) and component (F) are selected to provide condensation cure of the organopolysiloxane. In the case of condensation cure, organopolysiloxanes having two or more silicon-bonded hydroxy groups (ie silanol, considered as curable groups) are selected as component (D), and the organic hydrido silicon compound is an optional crosslinker It is selected as (E) and condensation curing catalysts known in the art, such as tin catalysts, are selected as component (F). Organopolysiloxanes useful as condensation curable organopolysiloxanes are any organopolysiloxanes comprising at least two silicon-bonded hydroxy groups (or silanol groups (SiOH)) in the molecule. Typically, one of the organopolysiloxanes described below as component (D) in the addition cure embodiment is a condensation cure embodiment, if two or more SiOH groups are additionally present, although alkenyl groups are not essential in the condensation cure embodiment. It can be used as organopolysiloxane in. Organic hydrido silicon compounds useful as optional crosslinkers (e) are as described below for component (E). Condensation catalysts useful as curing agents in this embodiment include the SiH group of the organic hydrido silicon compound (E) and the SiOH group of the diorganopolysiloxane (D) to cure the electrons by the formation of -Si-O-Si- bonds. Any compound that promotes a condensation reaction. Examples of suitable catalysts include metal carboxylates such as dibutyltin diacetate, dibutyltin dilaurate, tin tripropyl acetate, stannous octoate, stannous oxalate, stannous naphthalene; Amides such as triethyl amine, ethylenetriamine; And quaternized ammonium compounds such as benzyltrimethylammonium hydroxide, beta-hydroxyethyltrimethylammonium-2-ethylhexanoate and beta-hydroxyethylbenzyltrimethyldimethylammonium butoxide (US Patent No. 3,024,210). Reference).

In another embodiment, component (D), component (E) and component (F) may be selected to provide free radical curing of the organopolysiloxane. In such embodiments, the organopolysiloxane may be any organopolysiloxane, but typically the organopolysiloxane has two or more alkenyl groups. Thus, any of the organopolysiloxanes described above as suitable types for component () D ′) in the addition curing embodiment may also be used in the free radical embodiment of the present invention. Crosslinkers (E) are not required but may be helpful in the free radical cure embodiment. The curing agent (F) may be selected from any of the free radical initiators mentioned above for the selection of component (C).

In addition to the main components (A) to (F) mentioned above, trace amounts (ie, less than 50% by weight of the total composition) of one or more optional additives (G) may be incorporated in the elastomeric compositions of the invention. Such optional additives can be exemplified by the following non-limiting examples: extended fillers such as quartz, calcium carbonate and diatomaceous earth; Pigments such as iron oxide and titanium oxide; Fillers; For example, carbon black and finely divided metals; Heat stabilizers such as hydrated beeswax oxide, calcium hydroxide, magnesium oxide; And flame retardants such as halogenated hydrocarbons, alumina trihydrate, magnesium hydroxide, wollastonite, organophosphorus compounds and other fire retardant (FR) materials. Such additives are typically added to the final composition after static curing, but they can also be added to any portion in their formulation if they do not conflict with the static vulcanization mechanism. Such additives may be the same as or different from the additional ingredients added to prepare the cured elastomeric compositions described below.

The mixing of step (I) can be carried out in any device capable of uniformly mixing components (B) to (G) and elastomer (A). Typically, mixing by extrusion process is performed in a twin screw extruder. The order of mixing of the components (A) to (F) is not critical. Typically, component (G) is added after component (F), but is not critical unless it conflicts with the curing of the organopolysiloxane (e.g., component (G) is an elastomer (A) and / or a silicone substrate (D) And premixed with.

In one embodiment of the method of the invention, components (D) to (F) are first uniformly mixed to form a silicone compound. Components (A) to (C) are mixed with the silicone compound in step (I).

In one embodiment of the process of the invention, the mixing of step (I) is provided from a twin screw extruder. In a more preferred embodiment, the mixing time in the twin screw extruder is less than 3 minutes, or alternatively less than 2 minutes.

The second step (II) of the process of the invention statically vulcanizes the organopolysiloxane. The static vulcanization step cure the organopolysiloxane. Step (II) occurs after the mixing step (I). The static vulcanization step means to vulcanize the organopolysiloxane without further mixing of the product of step (I). For example, the mixed product from step (I) can simplify the process for curing the organopolysiloxane, such as heating the product of step (I). Typically, the product of step (I) is heated at a temperature sufficient to cure the organopolysiloxane. This temperature depends on the presence of the curing agent and on its chemical properties. In a preferred embodiment, the curing agent is present and organic peroxide as discussed above. In this embodiment, the half life of the organic peroxide should be short enough for the time and temperature constraints of step (II). Depending on the choice of curing agent, vulcanization may occur at atmospheric conditions.

The present invention also relates to elastomeric compositions prepared according to the methods taught herein and further to cured elastomeric compositions prepared therefrom. The inventors have found unique and useful elastomeric compositions as the techniques of the present invention have been demonstrated by the intrinsic physical properties of elastomeric compositions with respect to compositions of elastomers and similar formulations based on silicones made by other methods or techniques. I believe in providing. In addition, the cured elastomeric compositions as described below, made from the elastomeric compositions of the present invention, also have unique and useful properties. For example, cured elastomers made from the elastomeric compositions of the present invention have surprisingly good low and high temperature properties and improved processability.

The cured elastomeric composition of the present invention can be prepared by curing the elastomer component (A) of the elastomeric composition of the present invention through known curing techniques. The hardening of the elastomer and the additional ingredients added before curing are well known in the art and depend on the choice of elastomer (A). Any of these known techniques and additives can be used to cure the elastomeric compositions of the present invention and to prepare cured elastomers therefrom.

Additional components may be added to the elastomeric composition prior to curing the elastomeric component. This includes blending other elastomeric or other elastomeric compositions into the elastomeric composition of the present invention. This additional component may also be any component or element conventionally added to the elastomer or elastomer gum to prepare a cured elastomer composition. Typically, such ingredients may be selected from fillers, processing aids and therapeutic agents. Many commercially available elastomers may already contain such additional components. Elastomers having such additional components can be used as component (A) mentioned above, provided that step (II) of the process of the present invention does not inhibit static vulcanization of the silicone substrate. Alternatively, such additional components may be added to the elastomeric component prior to final curing of the elastomeric component.

The cured elastomeric composition may also include a filler. Examples of fillers include carbon black; Coal dust; Silica, metal oxides such as iron oxide and zinc oxide; Zinc sulfide; Calcium carbonate; Wollastonite, calcium silicate, barium sulfate and other materials known in the art.

Cured elastomer compositions include automobiles, ships, and aircraft; Chemical and petroleum plants; Electrical wires and cables: food processing equipment; Nuclear power generation device; space; Medical use; And other applications in which the oil and gas drilling industry and other applications typically use high performance elastomers such as ECO, FKM, HNBR, acrylic rubbers and silicone elastomers are intended for use in, but not limited to, applications. Illustrated as, but not limited to, O-rings, gaskets, seals, liners, hoses, tubing, diaphragms, boots, valves, belts, blankets, coatings, rollers, molded parts, extruded sheets, caulks, and extrudates It is useful in a variety of applications to organize a variety of products.

Example

The following examples are presented to further illustrate the compositions and methods of the present invention, but are not to be construed as limiting the invention as described in the appended claims. All parts and percentages in the examples are by weight unless otherwise stated and all measurements are obtained at approximately 23 ° C.

matter

GP-50 is a Silastic ^R GP-50, a silicone rubber substrate marketed by Dow Corning Corporation, Midland, Michigan, USA.

LS-2840 is a silicone ^R LS-2840 fluorosilicone rubber based silicone rubber substrate marketed by Dow Corning Corporation of Midland, Michigan, USA.

LS 5-2040 is a silicone ^R LS 5-2040 fluorosilicone rubber based silicone rubber substrate marketed by Dow Corning Corporation of Midland, Michigan, USA.

LS 4-9040 is a silicone ^R LS 4-9040 fluorosilicone rubber, a silicone rubber substrate sold by Dow Corning Corporation of Midland, Michigan, USA.

HT-1 is a masterbatch of cerium hydroxide in a dimethyl silicone rubber carrier and is marketed by Dow Corning Corporation, Midland, Michigan, as a silicone ^R HT-1 modifier.

TAIC is also known as triallyl-1,3,5-triazine-2,4, also known as triallyl isocyanurate, available from Aldrich Chemical Company, Inc. 6- (1H, 3H, 5H) -trione (CAS # 1025-15-6).

Rocks looper (Luperox) ^R F is a di- (2-tert-butylperoxyisopropyl) benzene, and rocks the looper (LUPEROX) and the Atofina Chemical's,, Inc. (Atofina Chemicals, Inc.) as a commercially available ^R F .

Barox (VAROX) is known as Barox ^R DBPH-50. 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane in inert fillers commercially available from Vanderbilt, Co., Inc. (RT Vanderbilt, Company, Inc.).

N990 is Thermal Black N 990, a carbon black (CAS # 1333-86-4) sold by Degussa Engineered Carbons.

Austin Black is Austin Black ^R , a carbon black sold by Coal Fillers Incorporated.

ZnO is zinc oxide USP powder (CAS # 1314-13-2) Hall and the Zinc Corporation of America.

Silicone Compound A is based on Silastic ^R LCS-755 silicone rubber sold by Dow Corning Corporation (100 parts), 9330 transparent zinc oxide (5 parts) and Barox (0.4 parts) sold by Akrochem Corporation. It is a silicone compound.

EPDM is a low diene containing ethylene-propylene terpolymer (EPDM) and is commercially available from Dupont Dow Elastomers, LLC as Nordel ^R IP NDR 3640.00.

G902 is 1-propene, 1,1,2,3,3,3-hexafluoro with 1,1-difluoroethane and tetrafluoroethane iodine modified fluoroelastomer (CAS # 25190-89-0) It is a low-polymer and is commercially available from Daikin America, Inc. as DAI-EL ^™ fluoroelastomer G-902.

Test method

Tensile, elongation and 100% modulus properties of the cured elastomeric composition are determined by a procedure based on ASTM D 412. Shore Durometer is measured by a procedure based on ASTM D 2240. Permeability is assessed using a Payne cup by a modified ASTM E96 method. The CElO test fuel is 10% ethanol in Reference Fuel C. The CElO is placed in the permeation cup, the rubber diaphragm is placed on top of the cup and then tightened with a sealing rig fixed to the bottom with a set screw. The cup is converted for fuel contact directly at the diaphragm. The weight loss is measured until the permeation rate is constant. The permeation rate is calculated by ASTM E96 using the surface area of the diaphragm and recorded in mm-gram / m ² · day.

Example 1

GP-50 (60 g) and Ruperox F (0.2 g) are mixed in a two roll mill to form a silicone compound. This silicone compound (60.2 g) and EPDM (140 g) were added and added to a 379 ml Haake mixer equipped with a Banbury roller at 15O < 0 > C and 100 rpm (rotation in minutes). After about 2.5 minutes, before the torque increases, the material temperature is removed and placed in the press for 10 minutes at 177 ° C. Split the elastomeric composition little by little. Sample 1A is likewise further blended. Sample 1B is heat aged for 16 hours / 90 ° C. and then compounded. The resulting EPDM elastomeric composition (50 g) is combined with barox (3 g), N990 (8 g), Austin black (4 g) and ZnO (2 g) in a two roll mill and the components are mixed until homogeneous.

Example 2

Without blending, GP-50 (60 g) and EPDM (140 g) are added to a 379 ml batch Hake mixer equipped with a Banbury roller at 150 ° C. and 100 rpm (rotation in minutes). After about 2.5 minutes, the elastomeric blend is removed. Split the elastomeric blend slightly. Sample 2A is likewise further blended. Sample 2B is heat aged for 16 hours / 90 ° C. and then compounded. The resulting elastomeric blend (50 g) was combined with Luperox F (0.05 g), Barrox (3 g), N990 (8 g), Austin Black (4 g) and ZnO (2 g) in a two roll mill and in Example 1 Provide the same final ingredients and mix the components until homogeneous.

Examples 1 and 2 are compression set at 177 ° C. for 20 minutes. The physical properties of the resulting cured elastomeric compositions and blends are summarized in Table 1.

Example number 1A 1B 2A 2B Shore A Durometer 57 58 55 56 Tensile Strength (MPa) 6.58 6.57 5.13 4.71 Elongation (%) 191 192 218 209

Example 3

For Sample 3A, silicone compounds A (142 g) and G902 (344 g) were added to a 310 ml batch mixer equipped with a Banbury roller at 90 ° C. and 125 rpm (rotation in minutes). Before the torque increases when the blend reaches 130 ° C., the blend is removed and placed in a press for 10 minutes at 200 ° C. to form a FKM elastomeric composition at 43 ° C. at 43 ml (1 + 10) @. For Sample 3B, the blend was allowed to reach 16O < 0 > C, reacted and then removed 5 minutes after the increase in torque to provide an FKM elastomeric composition at 67 < 0 > C at 67 < 0 > C (1 + 10) @. Sample 3B is identical to Sample 3A. The resulting FKM elastomeric composition (100 parts) is blended in rake until homogeneous with ZnO (3.44 parts), barox (2.06 parts) and TAIC (2.75 parts) and then in wheat. The sample is compression set at 160 ° C. for 10 minutes and then post cured at 200 ° C. for 4 hours. Sample 3A has a 60 Shore A durometer of 60, a tensile strength of 7.39 Mpa, an elongation of 320%, and a transmittance of 708 mm · gm / day · m ² . Sample 3B has a Shore A Durometer of 61, a tensile strength of 9.45 MPa, an elongation of 295%, and a transmittance of 2508 mm gm / m ² · day.

Example 4

LS-2840 (100 parts), ZnO (5 parts), HT-1 (1 part) and Barox (0.8 part) are mixed in a two roll mill to form a silicone compound. The silicone compound (257 g) and G902 (229 g) were added to a 310 ml Hake mixer equipped with a Banbury roller at 15O < 0 > C and 125 rpm (revolution in minutes). For Sample 4A, the blend is removed before the torque increases when the blend reaches 150 ° C. and then placed in a press at 177 ° C. for 10 minutes to form the FKM elastomeric composition. For Sample 4B, the blend is reacted in rake and removed 5 minutes after the torque increases.

The resulting FKM elastomeric composition (100 parts) is blended in rake until homogeneous with ZnO (2.35 parts), barox (1.41 parts) and TAIC (1.88 parts) and then in wheat. The sample is compression set at 160 ° C. for 10 minutes and then post cured at 200 ° C. for 4 hours. Physical properties are listed in Table 1.

Example 5

Samples 5A and 5B were prepared identically to Samples 4A and 4B, except the LS-2840 was replaced with 5-2040. Physical properties are listed in Table 2.

Example 6

Samples 6A and 6B were prepared identically to Samples 4A and 4B, except that LS-2840 was replaced with LS 4-9040 and 252 g of silicon compound were used. Physical properties are listed in Table 2.

2A 2B 3A 3B 4A 4B Permeability (mm · gm / day · m ²⁾ 850 1129 902 1143 1064 1244 Tensile strength (MPa) 6.90 6.93 6.42 6.64 5.04 6.27 Elongation (%) 341 335 423 339 284 303 Shore A Durometer 55 59 53 56 50 51

Example 7

FKM elastomeric compositions are prepared using a 25 mm Werner and Pfleiderer twin screw extruder with a processing section heated to an axial speed of 300 rpm and 50 ° C. at a production rate of 20 kg / hr. The process is started by adding silicone compound A at a feed rate of 70 g / min and then adding carbon fluoride elastomer (G902) to the extruder at a feed rate of 264 g / min. The blend is extruded into strips into a 12-foot horizontal oven set at 350 ° C. The resulting FKM elastomeric composition (100 parts) is blended in rake until homogeneous with ZnO (3.69 parts), barox (2.21 parts) and TAIC (2.95 parts) and then in wheat. The sample was press cured at 160 ° C. for 10 minutes and then cured at 200 ° C. for 4 hours to have a Shore A Durometer of 63, a tensile strength of 9.3 MPa, an elongation of 395%, and a permeability of 634 mm.gm/m. ² · days.

Claims (14)

Elastomer (A), Optional compatibilizer (B), Any catalyst (C), Silicone base material (D) containing curable organopolysiloxane, Optional crosslinker (E) and Mixing (I) an amount of curing agent (F) sufficient to cure the organopolysiloxane; and Statically vulcanizing the organopolysiloxane, wherein in the elastomeric base composition, the weight ratio range of elastomer (A) to silicone base (D) ranges from 95: 5 to 30:70 Way. The method of claim 1 wherein the silicon substrate is Diorganopolysiloxane (D ') containing two or more alkenyl groups having 2 to 20 carbon atoms, and And any optional filler (D "). The method of claim 2 wherein the crosslinker is present and is an organohydridosilicon compound. The method of claim 3 wherein the curing agent is a platinum catalyst. The method of claim 1 or 2, wherein the curing agent is a free radical initiator. The method of claim 1, wherein the elastomer is a hydrogenated copolymer of butadiene and acrylonitrile, a terpolymer of ethylene, propylene and diene, a copolymer of vinylidene fluoride and hexafluoropropene, vinylidene fluoride, hexa Terpolymers of fluoropropene and tetrafluoroethene or terpolymers of vinylidene fluoride, tetrafluoroethene and perfluoromethylvinyl ether. The process according to claim 1, wherein a compatibilizer (B) is present, An organic compound (B ¹ ) comprising two or more olefin groups, Organopolysiloxane (B ² ) comprising two or more alkenyl groups, Olefin functional silanes (B ³ ) comprising at least one hydrolyzable group or at least one hydroxyl group bonded to a silicon atom, Organopolysiloxanes (B ⁴ ) having at least one organic functional group selected from amine, amide, isocyanurate, phenol, acrylate, epoxy and thiol groups, Dehydrofluorination agent (B ⁵ ) and A method selected from any combination of component (B ¹ ), component (B ² ), component (B ³ ), component (B ⁴ ) and component (B ⁵ ). The process according to claim 1, wherein catalyst (C) is present and selected from organic peroxides. The method of claim 1 wherein component (D) through (F) are first mixed to form a silicone compound. The process according to claim 1, wherein step (I) is carried out in an extruder. The process of claim 1 wherein static vulcanization occurs by heating the mixture resulting from step (I). A product made by the method of claim 1. A cured elastomeric composition prepared from the product of claim 12. An article comprising the cured elastomeric composition of claim 13.