JP2008505207A - Elastomer silicone vulcanizate - Google Patents

Abstract

A method for preparing an elastomer composition is disclosed:
(I) (A) Elastomer (B) Optional compatibilizer (C) Optional catalyst (D) Silicone base containing curable organopolysiloxane (E) Optional crosslinker (F) The organic poly Mixing a sufficient amount of curing agent to cure the siloxane, and then (II) statically vulcanizing the organopolysiloxane, wherein the organopolysiloxane is based on the silicone base (D) in the elastomer base composition The weight ratio of the elastomer (A) is in the range of 95: 5 to 30:70. The elastomer composition obtained by this method and the cured elastomer composition prepared therefrom have good low and high temperature properties.

Description

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

  The present invention relates to a method of preparing an elastomer composition comprising a silicone and another elastomer, which is based on static vulcanization of the silicone. The invention further relates to the product prepared by this method and to the cured elastomer composition obtained therefrom.

  Silicone rubber is characterized by good high and low temperature properties, weather resistance, and processability. There is a need to modify other elastomers to efficiently improve their performance at extreme temperatures. In particular, there is a need to provide elastomeric compositions for use in various applications where high temperature and / or low temperature properties are required. There is also a need to modify elastomers to efficiently improve their processability.

  Only relatively few successes have given modified elastomers by the addition or combination of siloxane-based polymers. A stable and uniform mixture is difficult to obtain due to the incompatibility of the elastomer with these siloxane-based polymers. The loop must be crosslinkable. Some examples that provide elastomeric and silicone rubber compositions are US Pat. No. 4,942,202, US Pat. No. 5,010,137, US Pat. No. 5,171,787. And US Pat. No. 5,350,804.

  U.S. Pat. No. 4,942,202 teaches rubber compositions and vulcanized rubber products. The '202 composition comprises an organic peroxide under shear deformation, (I) a silicone rubber, (II) a saturated elastomer that does not react with the organic peroxide when used alone, and ( III) Prepared by reacting the silicone rubber with another elastomer that is crosslinkable in the presence of an organic peroxide. Other elastomers (III) are also crosslinkable or highly miscible with component (II).

  US Pat. No. 5,010,137 teaches rubber compositions, which include elastomers as well as oil seals and rubber hoses derived therefrom. The composition of the '137 specification combines a polyorganohydrogensiloxane and a Group VIII transition metal compound with a rubber-forming polymer comprising (I) a vinyl-containing polyorganosiloxane and (II) an organic rubber; The resulting compound is obtained by subjecting it to hydrosilylation while applying shear deformation.

  US Pat. No. 5,171,787 teaches silicone-based composite rubber compositions and uses thereof. The composition of '787 includes (A) a rubber-forming polymer comprising a polyorganosiloxane and an organic rubber, (B) a silicon compound having at least two hydrolyzable groups per molecule, and , (C) combining heavy metal compounds, amines, or quaternary ammonium salts that catalyze these hydrolysis and condensation reactions, while allowing the resulting formulation to undergo hydrolysis and condensation reactions, The formulation is kept free from deformation by shearing, and a crosslinking agent is subsequently added and prepared by subsequent crosslinking of the organic rubber.

  US Pat. No. 5,350,804 teaches a composite rubber composition which has (a) a Mooney viscosity of at least 70 at 100 ° C. and forms a matrix phase of the composite rubber composition. An organic rubber elastomer composition, and (b) a cured silicone rubber as a dispersed phase in the matrix phase.

  While these patents provide progress in the field, the elastomers need to be specially modified to be efficient in providing lower cost, higher performance elastomeric systems while maintaining the inherent physical properties of these systems. Sex still exists. In particular, there is a need to provide elastomeric compositions for use in various applications where high and / or low temperature properties are required as well as resistance to fuels, oils, exhaust gases, or chemicals.

  The present invention provides an elastomer composition, which is based on incorporating silicone with other elastomers and uses a static vulcanization process. These elastomeric compositions are obtained from the new mixing process of the present invention. These new mixing processes provide a composition having a significant amount of silicone rubber based composition incorporated into another elastomer. However, the resulting cured elastomer composition prepared from the fluorocarbon elastomer composition of the present invention maintains many of the desirable physical properties and attributes of the elastomer.

The present invention provides a method of preparing an elastomer composition, which contains both an elastomer and a silicone, wherein the silicone base is mixed with another elastomer, the silicone base continuing. In the elastomer, it is statically vulcanized. The present invention therefore relates to a method of preparing an elastomer composition:
(I) (A) Elastomer
(B) Optional compatibilizer
(C) any catalyst
(D) Silicone base containing curable organopolysiloxane
(E) Any cross-linking agent
(F) mixing a sufficient amount of curing agent to cure the organopolysiloxane, and then (II) statically vulcanizing the organopolysiloxane, wherein in the elastomer base composition The weight ratio of the elastomer (A) to the silicone base (D) is in the range of 95: 5 to 30:70.

  The present invention further relates to an elastomer composition obtained by this method and a cured elastomer composition prepared therefrom.

  Component (A) is an elastomer and has a glass transition temperature (Tg) below room temperature, below 23 ° C, below 15 ° C, or below 0 ° C. “Glass transition temperature” means the temperature at which a polymer changes from a glassy state to a rubbery state. The glass transition temperature can be determined by conventional methods such as dynamic mechanical analysis (DMA) and differential calorimeter (DSC). As used herein, << elastomer >> excludes silicone-based elastomers, also known as silicone rubber. The elastomer component (A) can be selected from any of the major classes of elastomers and rubbers (ASTM classification is shown in parentheses) and these are 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 polyethylene (CSM), acrylic rubber ( ACM), epichlorohydrin rubber (ECO), ethylene-vinyl acetate rubber (EVM), ethylene-acrylic rubber, ethylene-α olefin copolymer rubber, ethylene-α olefin-diene terpolymerized rubber (EPDM), fluoride Carbon elastomer (FKM), and known as hydrogenated nitrile rubber (HNBR).

  Alternatively, the elastomer is a high performance elastomer such as 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-alpha olefin-diene terpolymerized rubber (EPDM), hydrogenated nitrile rubber (HNBR), and fluorocarbon elastomer (FKM).

  In the chemically modified elastomer embodiments described below, (A) is selected from an elastomer comprising a polymer capable of reacting with a compatibilizer (B) and optionally a catalyst (C) to produce a modified elastomer. While not wishing to be bound by any theory, the inventors believe that any elastomer or modified elastomer can be selected as component (A) in the chemically modified embodiment. Provided that the elastomer contains at least one group capable of reacting with at least a portion of the silicone base. In other words, the elastomer should be able to react with the silicone base via the actual curing mechanism selected for the organopolysiloxane. A curing agent (F) is added to the organopolysiloxane, component (D), and optionally the crosslinking component (E) to cure the organopolysiloxane via a static vulcanization process. Typically, during the static vulcanization process, i.e. step (II), the chemistry of curing taking place on the surface of the silicone compound can also react with the elastomer, which is further contained within the elastomer within the silicone. To disperse. Representative non-limiting examples of reactive groups on the elastomer also include methyl, methylene, vinyl, and halogen. Methyl or methylene groups on the elastomer can react with the peroxide and can be selected as a curing agent for the silicone compound, thus forming a bond between the organopolysiloxane and the elastomer. As another example, vinyl groups on the elastomer can react via its addition or radical cure mechanism.

  It will be appreciated that the elastomeric component (A) can be a polymer mixture. However, in the chemically modified elastomeric embodiment, at least 2%, alternatively at least 5%, alternatively at least 10% by weight of the elastomeric composition can react with the chemistry of curing of the organopolysiloxane. It should contain a polymer with groups.

  The optional compatibilizer (B) can be selected from any hydrocarbon, organosiloxane, fluorocarbon, or combinations thereof, to promote mixing of the silicone base (D) with the elastomer (A), It is expected to modify the elastomer, producing a mixture having a continuous elastomeric phase and a discontinuous silicone phase (ie, an internal phase). In general, the compatibilizer can be one of two types. In the first embodiment, referred to herein as a physical compatibilizer, the compatibilizer is selected from any hydrocarbon, organosiloxane, fluorocarbon, or combination thereof, and elastomer (A It is not expected to react with), but still promotes mixing of the elastomer with the silicone base. In a second embodiment, referred to herein as a chemical compatibilizer, the compatibilizer is selected from any hydrocarbon, organosiloxane, fluorocarbon, or combination thereof, the elastomer and It is believed that it can chemically react with the silicone rubber. However, in any embodiment, the compatibilizer should not prevent static curing of the organopolysiloxane component described below.

  In the physical modification embodiment, compatibilizer (B) may be selected from any compatibilizer known in the art to promote silicone-based mixing with the elastomer.

In the chemical modification embodiment, typically the compatibilizer (B) is an organic (ie, non-silicone) compound (B ¹ ) containing two or more olefin groups, at least two alkenyl groups. organopolysiloxanes which contain (B ^2), silane (B ³⁾ having at least one hydrolyzable group or at least one olefinic functional groups that also contain hydroxyl groups bound to the silicon ^atom, amine, amide , Organopolysiloxane (B ⁴ ) having at least one organic functional group selected from isocyanurates, phenols, acrylates, epoxies, and thiol groups, dehydrofluorinating agents (B ⁵ ), and (B
¹ ), (B ² ), (B ³ ), (B ⁴ ), and (B ⁵ ) can be selected from any combination.

Organic compatibilizers (B ′) are, among others, diallyl phthalate, triallyl isocyanurate, 2,4,6-triallyloxy-1,3,5-triazine, triallyl trimesate,
1,5-hexadiene, low molecular weight polybutadiene, 1,7-octadiene, 2,2′-diallylbisphenol A, N, N′-diallyltartaric acid diamide, diallyl urea (urea)
, Diallyl oxalate, and compounds such as divinyl sulfone.

  The compatibilizing agent (B ″) may be selected from linear, branched or cyclic organopolysiloxanes and has at least two alkenyl groups in the molecule. Examples of such organopolysiloxanes are divinyltetramethyldisiloxane, cyclotrimethyltrivinyltrisiloxane, cyclotetramethyltetravinyltetrasiloxane, hydroxy-endcapped polymethylvinylsiloxane, hydroxy-terminated polymethylvinylsiloxane-co-poly. Also included are dimethylsiloxane, dimethylvinylsiloxy-terminated polydimethylsiloxane, tetrakis (dimethylvinylsiloxy) silane, and tris (dimethylvinylsiloxy) phenylsilane. Alternatively, the compatibilizer (B '') is a hydroxy-terminated polymethylvinylsiloxane [HO (MeViSiO) xH] oligomer and has a viscosity of about 25-100 mPa.s. It has a viscosity of s and contains 20-35% vinyl groups and 2-4% silicon-bonded hydroxyl groups.

  The compatibilizer (B ′ ″) is a silane and contains at least one alkylene group and typically contains a vinyl unsaturated moiety, as well as from hydrolyzable groups or hydroxyl groups. Contains at least one selected silicon bonding moiety. Suitable hydrolyzable groups include alkoxy, aryloxy, acyloxy, or amide groups. Examples of such silanes are vinyltriethoxysilane, vinyltrimethoxysilane, hexenyltriethoxysilane, hexenyltrimethoxy, methylvinyldisianol, octenyltriethoxysilane, vinyltriacetoxysilane, vinyltris (2-ethoxyethoxy) Silane, methylvinylbis (N-methylacetamido) silane, and methylvinyldisilanol.

  The compatibilizing agent (B "") is an organopolysiloxane having at least one organic functional group selected from amine, amide, isocyanurate, phenol, acrylate, epoxy, and thiol groups.

  It is possible that a portion of the curable organopolysiloxane of silicone base component (D) below can also function as a compatibilizer. For example, catalyst (C) can be used to first react a portion of the silicone-based (D) curable organopolysiloxane with the elastomer to produce a modified elastomer. The modified elastomer is then further mixed with the remaining silicone base (D) containing the curable organopolysiloxane and the organopolysiloxane is statically vulcanized as follows.

  The amount of compatibilizer used per 100 parts of elastomer can be determined by routine experimentation. Typically, 0.05 to 15 parts by weight, alternatively 0.05 to 10 parts by weight, alternatively 0.1 to 5 parts of the compatibilizer is used for each 100 parts of elastomer (A). .

Optional component (C) is a catalyst. Typically, the catalyst is used in the chemical modification embodiment. Thus, this is typically a radical initiator and is selected from any organic compound known in the art to generate free radicals at elevated temperatures. The initiator is not particularly limited, and may be any known azo or diazo compound such as 2,2′-azobisisobutyronitrile, preferably hydrogen peroxide, diacyl peroxide, ketone Selected from organic peroxides such as peroxides, peroxyesters, dialkyl peroxides, dicarbonate peroxides, ketal peroxides, peracids, acylalkylsulfonyl peroxides, and alkyl monoperoxydicarbonates. However, the key requirement is that the initiator has a sufficiently short half-life, so that within the time and temperature constraints of step (I), the compatibility of the compatibilizer (B) with the elastomer (A) Promote the reaction. In turn, the modification temperature depends on the type of elastomer and compatibilizer chosen, and is typically so low that it is consistent with uniform mixing of components (A)-(C). Specific examples of suitable peroxides that may be used in accordance with the method of the present invention are:
2,5-dimethyl-2,5-di (tert-butylperoxy) hexane;
Benzoyl peroxide;
Dicumyl peroxide;
t-butylperoxy-O-toluic acid;
Cyclic peroxyketals;
t-butyl hydroperoxide;
t-butyl peroxypivalate;
Lauroyl peroxide;
t-amyl peroxy 2-ethylhexanoate;
Vinyltris (t-butylperoxy) silane;
Di-t-butyl peroxide;
1,3-bis (t-butylperoxyisopropyl) benzene;
2,2,4-trimethylpentyl-2-hydroperoxide;
2,5-bis (t-butylperoxy) -2,5-dimethylhexyne-3;
t-butylperoxy-3,5,5-trimethylhexanoate;
Cumene hydroperoxide;
t-butyl peroxybenzoate (benzoic acid); and diisopropylbenzene monohydroperoxide. Less than 2 parts by weight of peroxide are typically used per 100 parts of elastomer. Alternatively, 0.05-1 part and 0.2-0.7 part may also be used.

Component (D) is silicone-based and includes a curable organopolysiloxane (D ′) and optionally a filler (D ″). A curable organopolysiloxane is defined herein as any organopolysiloxane having at least two curable groups present in its molecule. Organopolysiloxanes are well known in the art and often contain any number of R ₃ SiO _0.5 (M units), R ₂ SiO (D units), RSiO _1.5 (T units), or SiO ₂ ( Q unit), wherein R is independently any monovalent hydrocarbon group. Alternatively, organopolysiloxanes often have the following general formula:
_{[R m Si (O) 4} -m / 2] n
In which R is independently any monovalent hydrocarbon group, m = 1-3, and n is at least 2.

  The organopolysiloxane in the silicone base (D) must have at least two curable groups in its molecule. As used herein, a curable group is itself or another hydrocarbon group or any hydrocarbon group that can react with a crosslinking agent to crosslink the organopolysiloxane. Defined. This cross-linking results in a cured organopolysiloxane. Representative of the types of curable organopolysiloxanes that can be used in the silicone base are organopolysiloxanes known in the art to produce silicone rubber as it cures. Non-limiting examples of such organopolysiloxanes are disclosed in Kirk-Othmer << Encyclopedia of Chemical Technology >>, 4th edition, Vol. 22, pp. 82-142, John Wiley & Sons, NY, Incorporated in the specification. Typically, the organopolysiloxane can be cured through a number of crosslinking mechanisms, using various curing groups, curing agents, and optionally crosslinking agents on the organopolysiloxane. While there are many cross-linking mechanisms, three of the more common cross-linking mechanisms in the industry for preparing silicone rubber from curable organopolysiloxanes are free radical initiated cross-linking, hydrosilylation or addition Curing and condensation curing. Thus, the curable organopolysiloxane can be selected from, but not limited to, any organopolysiloxane that can undergo any one of these cross-linking mechanisms described above. The choice of components (D), (E), and (F) is consistent with the choice of curing or crosslinking mechanism. For example, if hydrosilylation or addition curing is selected, then a silicone base containing an organopolysiloxane having at least two vinyl groups (curable groups) is used as component (D ′) and organic A hydridosilicon compound is used as component (E) and a platinum catalyst is used as component (F). For condensation cure, a silicone base is selected as component (D) that includes an organopolysiloxane having at least two silicon-bonded hydroxy groups (hydroxyl groups, ie, silanols are considered to be curable groups as described above). And a condensation curing catalyst known in the art, such as a tin catalyst, is selected as component (F). For free radical initiated crosslinking, any organopolysiloxane can be selected as component (D), provided that this combination cures within the time and temperature constraints of the static vulcanization step (II). A radical initiator (initiator) is selected as component (F). Depending on the choice of component (F) in the crosslinking initiated by such free radicals, any alkyl group such as methyl can be considered as a curable group as described above, which is This is because it crosslinks under conditions initiated by free radicals.

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

  Conveniently expressed as a weight ratio of elastomer (A) to silicone base (D), typically 95: 5 to 30:70, alternatively 90:10 to 40:60, alternatively 80:20. It is in the range of ˜40: 60.

In the addition cure embodiment of the present invention, the selection of components (D), (E), and (F) is such that during the vulcanization process, a silicon rubber is produced via a hydrosilylation cure procedure. obtain. This embodiment is referred to herein as a hydrosilylation cure embodiment. Thus, in the hydrosilylation cure embodiment, (D ′) is selected from diorganopolysiloxane rubbers, which contain at least 2 alkenyl groups having 2 to 20 carbon atoms, optionally ( D ″) is a reinforcing filler. Said alkenyl group is in particular exemplified by vinyl, allyl, butenyl, pentenyl, hexenyl and decenyl, preferably vinyl or hexenyl. The position of the alkenyl functional group is not critical and may be attached at the end of the molecular chain, at a non-terminal position on the molecular chain, or at both positions. Typically, the alkenyl group is vinyl or hexenyl, and this group is present in the diorganopolysiloxane at a level of 0.0001 to 3 mol%, alternatively 0.0005 to 1 mol%. The remaining (ie, non-alkenyl) silicon-bonded organic groups of the diorganopolysiloxane are independently selected from hydrocarbon or halogenated hydrocarbon groups, which do not contain aliphatic unsaturation (partial). These are especially alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, and hexyl; cycloalkyl groups such as cyclohexyl and cycloheptyl; phenyl, tolyl, and xylyl Aryl groups having 6-12 carbon atoms; aralkyl groups having 7-20 carbon atoms such as benzyl and phenylethyl (phenethyl); and 3,3,3-trifluoropropyl and It may be exemplified by a halogenated alkyl group having 1-20 carbon atoms, such as chloromethyl. Of course, it will be appreciated that these groups are selected such that the diorganopolysiloxane has a glass temperature below room temperature and the cured polymer is therefore an elastomer. Typically, these non-alkenyl silicon-bonded organic groups in the diorganopolysiloxane form at least 85, or at least 90 mol% of the organic groups in the diorganopolysiloxane.
Thus, the polydiorganosiloxane (D ′) can be a homopolymer, copolymer or terpolymer and contains such organic groups. Examples are homopolymers containing dimethylsiloxy units, homopolymers containing 3,3,3-trifluoropropylmethylsiloxy units, copolymers containing dimethylsiloxy units and phenylmethylsiloxy units, dimethylsiloxy units And 3,3,3-trifluoropropylmethylsiloxy units, copolymers of dimethylsiloxy units and diphenylsiloxy units, and terpolymers of dimethylsiloxy units, diphenylsiloxy units, and phenylmethylsiloxy units, Includes others. The molecular structure is also not critical, exemplified by linear structures and partially branched linear structures, these linear systems being most typical.

Specific examples of diorganopolysiloxane (D ′) are:
Trimethylsiloxy endcapped dimethylsiloxane-methylvinylsiloxane copolymer; trimethylsiloxy endcapped methylphenylsiloxane-dimethylsiloxane-methylvinylsiloxane copolymer; trimethylsiloxy endcapped 3,3,3-trifluoropropylmethylsiloxane copolymer; trimethylsiloxy endcapped 3 , 3,3-trifluoropropylmethyl-methylvinylsiloxane copolymer; dimethylvinylsiloxy end-capped dimethylpolysiloxane; dimethylvinylsiloxy endcapped dimethylsiloxane-methylvinylsiloxane copolymer; dimethylvinylsiloxy endcapped methylphenylpolysiloxane; dimethylvinylsiloxy End-capped methylphenylsiloxane-dimethylsiloxane-methylvinylsiloxa Copolymers; encompasses and similar copolymers, wherein at least one end group is dimethylhydroxysiloxy. Typical systems for low temperature applications include methylphenylsiloxane-dimethylsiloxane-methylvinylsiloxane copolymers and diphenylsiloxane-dimethylsiloxane-methylvinylsiloxane copolymers, particularly where the molar content of the dimethylsiloxane units is Is about 85-95%.

  The organic polysiloxane may also be a combination of two or more organic polysiloxanes. Alternatively, the diorganopolysiloxane (D ′) is a linear polydimethylsiloxane homopolymer, preferably blocked at each end of the molecule by a vinyl group, or at least one vinyl group is also present in the main chain. Contained along with such homopolymers.

  For purposes of the present invention, the preferred diorganopolysiloxane is a diorganopolysiloxane rubber having a Williams plasticity number of at least about 30 as determined by the American Society for Testing and Materials (ASTM) test method 926. Has sufficient molecular weight to impart. There is no absolute upper limit to the plasticity of component (D '), but this value is generally constrained by realistic considerations of processability in conventional mixing equipment. Typically, the plasticity number should be 40-200, alternatively 50-150.

  Methods for preparing highly organized unsaturated group-containing diorganopolysiloxanes are well known and do not require detailed discussion here.

Optional component (D ″) may be any filler and is known to enhance diorganopolysiloxane (D ′), preferably fuming silica and precipitated silica, silica aerosol, and Selected from minced and heat-stable minerals such as titanium dioxide having a specific surface area of at least about 50 m ² / gram. Fuming silica is a typical reinforcing filler based on its large surface area and can be up to 450 m ² / gram. Alternatively, fuming silica having a surface area of 50-400 m < ² > / g or 90-380 m < ² > / g can be used. The filler is added at a level of about 5 to about 150 parts by weight, alternatively 10 to 100 parts by weight, alternatively 15 to 70 parts by weight, for each 100 parts by weight of diorganopolysiloxane (D ′).

  The filler is typically treated to make its surface hydrophobic, as is typically practiced in the silicone rubber art. This can be accomplished by reacting the silica with a liquid organosilicon compound, which contains silanol groups or precursors that can be hydrolyzed to silanol groups. Compounds that can be used as filler treating agents, also referred to in the silicone rubber industry as anti-creping agents or plasticizers, are low molecular weight liquid hydroxy- or alkoxy-terminated polydiorganosiloxanes, hexa-organic dioxysiloxanes. Includes components such as siloxane, cyclodimethylsilazane, and hexaorganodisilazane.

  Component (D) may also contain other materials commonly used in silicone rubber formulations, which include antioxidants, crosslinking aids, processing agents, dyes, and other additives known in the art. However, the present invention is not limited to these and does not interfere with the following step (II).

  In the hydrosilylation cure embodiment of the present invention, compound (E) is added, which is an organohydridosilicon compound (E ') and crosslinks with a diorganopolysiloxane (D'). The organohydridosilicon compound is an organopolysiloxane containing at least two silicon-bonded hydrogen atoms in each molecule, between the alkenyl functionality of (D ′) and the static vulcanization step (II) of the process. To react. An additional (molecular weight) restriction is that component (E ′) must have at least about 0.1 wt% hydrogen, alternatively 0.2-2, alternatively 0.5-1.7% silicon-bonded hydrogen. That is. Those skilled in the art will of course recognize that the diorganopolysiloxane (D ′) or component (E ′) or both must have more than two functional groups to cure the diorganopolysiloxane (ie, The sum of these functional groups must average more than 4). The position of silicon-bonded hydrogen in component (E ') is not critical and may be bonded at the molecular chain end, at a non-terminal position along the molecular chain, or at both positions. The silicon-bonded organic groups of component (E ′) are independently selected from any of the saturated or halogenated hydrocarbon groups described above in connection with the diorganopolysiloxane (D ′), and preferred embodiments thereof are also Is included. The molecular structure of component (E ') is also not critical and is exemplified by linear, partially branched linear, branched, cyclic, and network structures, with network, linear polymers or copolymers being typical. Of course, it is recognized that this component must be compatible with D '(ie, effective in curing the diorganopolysiloxane).

Component (E ′) is:
Low molecular weight siloxanes such as PhSi (OSiMe ₂ H) ₃ ;
Trimethylsiloxy end-capped methylhydridopolysiloxane;
Trimethylsiloxy end-capped dimethylsiloxane-methylhydridosiloxane copolymer;
Dimethylhydridosiloxy end-capped dimethylpolysiloxane;
Dimethylhydrogensiloxy end-capped methylhydrogen polysiloxane;
Dimethylhydridosiloxy end-capped dimethylsiloxane-methylhydridosiloxane copolymer;
Cyclic methylhydrogen polysiloxane;
Cyclic dimethylsiloxane-methylhydridosiloxane copolymer;
Tetrakis (dimethylhydrogensiloxy) silane;
A trimethylsiloxy end-capped methylhydridosiloxane polymer containing SiO _4/2 units;
A silicone resin composed of (CH ₃ ) ₂ HSiO _1/2 units and SiO _4/2 units;
A silicone resin composed of (CH ₃ ) ₂ HSiO _1/2 units, (CH ₃ ) ₃ SiO _1/2 units, and SiO _4/2 units;
A silicone resin composed of (CH ₃ ) ₂ HSiO _1/2 units and CF ₃ CH ₂ CH ₃ SiO _3/2 units; and (CH ₃ ) ₂ HSiO _1/2 units, (CH ₃ ) ₃ SiO _1/2 Illustrated by a silicone resin composed of units, CH ₃ SiO _3/2 units, PhSiO _3/2 units, and SiO _4/2 units, Ph represents a phenyl group hereinafter.

Typical organohydridosilicon compounds are polymers or copolymers, contain RHSiO units and are blocked by R ₃ SiO _1/2 units or HR ₂ SiO _1/2 units, where R is independently 1-20 carbons. Selected from alkyl groups having atoms, phenyl, or trifluoropropyl, typically methyl. Typically, the viscosity of component (E ′) is about 0.5 to 3,000 mPa.s at 25 ° C. s, or 1 to 2,000 mPa.s. s. Component (E ′) typically has 0.5 to 1.7 wt% silicon-bonded hydrogen. Alternatively, component (E ′) is selected from a polymer consisting essentially of methylhydridosiloxane units, or a copolymer consisting essentially of dimethylsiloxane units and methylhydridosiloxane units, 0.5-1.7% by weight 1 to 2,000 mPa.s at 25 ° C. It has a viscosity of s. Such typical systems have end groups selected from trimethylsiloxy or dimethylhydridosiloxy groups. Alternatively, component (E ′) is selected from a copolymer or network and includes resin units. The copolymer or network unit includes RSiO _3/2 units or SiO _4/2 units, and also includes R ₃ SiO _1/2 units, R ₂ SiO _2/2 units, and / or RSiO _3/2 units. Where R is independently selected from hydrogen, an alkyl group having 1 to 20 carbon atoms, phenyl, or trifluoropropyl, and is typically methyl. It is understood that R as sufficient hydrogen is selected such that component (E ′) typically has 0.5 to 1.7 weight percent silicon-bonded hydrogen. Typically, the viscosity of component (E ′) is about 0.5 to 3,000 mPa.s at 25 ° C. s, or 1 to 2,000 mPa.s. s. Component (E ′) may be a combination of two or more of the systems described above.

  The organohydridosilicon compound (E ') is used at a level sufficient to cure the diorganopolysiloxane (D') in the presence of component (F) and is as follows. Typically, the content is adjusted so that the molar ratio of SiH in it to Si-alkenyl in (D ') is greater than 1. Typically, this SiH / alkenyl ratio is less than about 50, alternatively 1-20, alternatively 1-12. These materials having SiH functional groups 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 ') and accelerates the diorganopolysiloxane cure. This is platinum black, platinum supported on silica (Pt—Si, Pt / Si), platinum supported on carbon (Pt—C, Pt / C), chloroplatinic acid, chloroplatinic alcohol solution, Platinum catalysts such as platinum / olefin complexes, platinum / alkenylsiloxane complexes, platinum / β-diketone complexes, platinum / phosphine complexes, etc .; rhodium catalysts such as rhodium chloride and rhodium chloride / di (n-butyl) sulfide complexes and others And exemplified by palladium catalysts such as palladium on carbon (Pd-C, Pd / C), palladium chloride, and others. Component (F ') is typically diluted with chloroplatinic acid; platinum dichloride; platinum tetrachloride; chloroplatinic acid and divinyltetramethyldisiloxane reacted with dimethylvinylsiloxy end-capped polydimethylsiloxane. A platinum complex catalyst prepared and produced according to U.S. Pat. No. 3,419,593 to Willing; U.S. Pat. No. 5,175,325 to Brown et al. Of platinum chloride and divinyltetramethyldisiloxane. Platinum-based catalysts, such as neutralized complexes prepared according to the specification, these patents are hereby incorporated by reference. Alternatively, the catalyst (F) is a neutralized complex of platinum chloride and divinyltetramethyldisiloxane.

  Component (F ′) is added to the composition in a catalytic amount sufficient to promote the reaction between the organopolysiloxane (D ′) and component (E ′), and thus the organopolysiloxane is Cure within the time and temperature limits of the mechanical vulcanization step (II). Typically, the hydrosilylation catalyst is added, thereby providing about 0.1 to 500 ppm, alternatively 0.25 to 50 ppm of metal atoms based on the total weight of the elastomer composition.

  In another embodiment, components (D), (E), and (F) are selected to provide condensation cure of the organopolysiloxane. For condensation curing, an organic polysiloxane having at least two silicon-bonded hydroxyl groups (ie, silanols are considered to be these curable groups) is selected as component (D), and an organic hydridosilicon compound is an optional crosslinking agent. The condensation cure catalyst selected as (E) and known in the art is like a tin catalyst and is selected as component (F). Organopolysiloxanes useful as condensation curable organopolysiloxanes are any organopolysiloxane containing in its molecule at least two silicon-bonded hydroxyl groups or silanol groups (SiOH). Typically, if at least two SiOH groups are further present, as component (D) in the addition cure embodiment, any of the following organopolysiloxanes is an organopolysiloxane in the condensation cure embodiment: The alkenyl group is not required in this condensation cure embodiment. The optional crosslinker (E) is the same as described below for component (E). In this embodiment, the condensation catalyst useful as the curing agent is any compound that promotes the condensation reaction between the SiOH group of the diorganopolysiloxane (D) and the SiH group of the organohydridosilicon compound (E). Yes, thus the former is cured by the formation of -Si-O-Si- bonds. Examples of suitable catalysts are metal carboxylates such as dibutyltin diacetate, dibutyltin dilaurate, tripropyltin acetate, stannous octoate, stannous oxalate, stannous naphthanate; amines such as triethylamine, ethylenetriamine And quaternary ammonium compounds such as benzyltrimethylammonium hydroxide, β-hydroxyethyltrimethylammonium-2-ethylhexoate, and β-hydroxyethylbenzyltrimethyldimethylammonium butoxide (see, for example, US Pat. No. 3, , 024,210 specification).

  In yet another embodiment, components (D), (E), and (F) can be selected to provide free radical curing of the organopolysiloxane. In this embodiment, the organopolysiloxane can be any organopolysiloxane, but typically the organopolysiloxane has at least 2 alkenyl groups. Thus, any of the organopolysiloxanes described above as suitable choices for (D ') in the addition cure embodiment can be used in the free radical embodiments of the present invention. A crosslinker (E) is not required, but may aid in the present free radical curing embodiment. The curing agent (F) can be selected from any of the free radical initiators described below with respect to the selection of component (C).

In addition to the main components (A) to (F) described above, a small amount (ie less than 50% by weight of the total composition) of one or more optional additives (G) is added to the elastomer composition of the present invention. Can be incorporated. These optional additives include the following non-limiting examples:
Bulking fillers such as quartz, calcium carbonate, and diatomaceous earth;
Pigments such as iron oxide and titanium oxide;
Fillers such as carbon black (graphite) and fragmented metals;
Thermal stabilizers such as hydrated cerium oxide, calcium hydroxide, magnesium oxide; and halogenated hydrocarbons, alumina trihydrate, magnesium hydroxide, wollastonite, organophosphorus compounds, and other difficulties It may be exemplified by a flame retardant such as a flame (FR) material. These additives are typically added to the final composition after static curing, but they may be added at any point during their preparation, provided they do not interfere with the static vulcanization mechanism . These additives may be the same as or different from the additional components added to prepare the cured elastomer composition described below.

  The mixing for step (I) can be carried out in any apparatus that can uniformly mix components (B)-(G) with (A) the elastomer. Typically, mixing by the extrusion process is carried out on a twin screw extruder. The order in which components (A)-(F) are mixed is not critical. Typically, (G) is added after (F), but is not critical as long as (G) does not interfere with the organopolysiloxane cure. For example, (G) can be premixed with elastomer (A) and / or silicone base (D).

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

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

  In the second step (II) of the method of the present invention, the present organic polysiloxane is statically vulcanized. The static vulcanization step cures the organopolysiloxane. Step (II) is performed after the mixing step (I). Static vulcanization refers to vulcanizing the organopolysiloxane without further mixing of the product of step (I). For example, the mixed product from step (I) may simply be subjected to a process for curing the organopolysiloxane such that the product of step (I) is heated. Typically, the product of step (I) is heated at a temperature sufficient to cure the organopolysiloxane. This temperature will depend on the presence of the curing agent and its chemical nature. In a preferred embodiment, the curing agent is present and is an organic peroxide, as discussed above. In this embodiment, the organic peroxide has a very short half-life, sufficient for the time and temperature constraints (conditions) of step (II). Depending on the choice of the curing agent, vulcanization can occur in atmospheric conditions.

  The present invention relates to elastomeric compositions prepared by the methods taught herein and further to cured elastomeric compositions prepared therefrom. The inventors believe that the technique of the present invention provides a unique and useful elastomeric composition, as demonstrated by the inherent physical properties of the elastomeric composition and prepared by other methods or techniques. It is against a similar combination composition of elastomer and silicone base. In addition, the cured elastomer composition is prepared from the elastomer composition of the present invention as described below and possesses unique and useful properties. For example, cured elastomers prepared from the elastomeric composition of the present invention have surprisingly good low and high temperature properties and improved processability.

  The cured elastomer composition of the present invention can be prepared by curing the elastomer component (A) of the elastomer composition of the present invention via a known curing technique. The cure of the elastomer and the additional components added prior to cure are well known in the art and will depend on the choice of elastomer (A). Any of these known techniques and additives can be used to cure the elastomer composition of the present invention and prepare a cured elastomer therefrom.

  Additional components can be added to the elastomer composition before the elastomer component is cured. These include blending other elastomers or other elastomer compositions into the elastomer composition of the present invention. These additional components can also be any components that are typically added to an elastomer or elastomer rubber for the purpose of preparing a cured elastomer composition. Typically, these components can be selected from fillers, processing aids, and therapeutic agents. Many commercially available elastomers may already contain these additional components. Elastomers having these additional components can be used as component (A) above, but do not interfere with the silicone-based static vulcanization in step (II) of the process of the present invention. Alternatively, such additional components can be added to the elastomer composition prior to final curing of the elastomer component.

  The cured elastomer composition may also include a filler. Examples of fillers are carbon black (graphite), coal dust, silica, metal oxides such as iron oxide and zinc oxide, zinc sulfide, calcium carbonate, wollastonite, calcium silicate, barium sulfate, and known in the art Others are also included.

  The cured elastomer composition is useful in a variety of applications such as building a variety of manufactured articles, including O-rings, gaskets, seals, liners, hoses, piping, diaphragms, boots, valves, valves, belts, blankets. Exemplified by, but not limited to, coatings, rollers, model articles, extruded sheets, caulking, and extruded articles, including automotive, marine, and aviation, transportation, chemical and petroleum plants, electricity, wires and cables, food For use in processing equipment, nuclear power plants, aerospace, medical, oil and gas drilling industries, and other application areas including, but not limited to, typically ECO, FKM, HNBR, acrylic rubber, And use high performance elastomers such as silicone elastomers.

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, but are set forth in the appended claims. All << parts >> and <<% >> in this example are on a weight basis and all measurements were obtained at approximately 23 ° C. unless otherwise indicated.
Materials GP-50 is a silicone rubber base and is marketed as Silastic® GP-50 by Dow Corning Corporation (Midland, MI).
LS-2840 is a silicone rubber base and is marketed by Dow Corning Corporation (Midland, MI) as Silastic® LS-2840 fluorosilicone rubber.
LS5-2040 is a silicone rubber base and is marketed by Dow Corning Corporation (Midland, MI) as Silastic® LS5-2040 fluorosilicone rubber.
LS4-9040 is a silicone rubber base and is marketed as Dow Corning Corporation (Midland, MI) as Silastic® LS4-9040 fluorosilicone rubber.
HT-1 is a cerium hydroxide masterbatch in dimethyl silicone rubber carrier and is marketed as a Silastic® HT-1 modifier by Dow Corning Corporation (Midland, MI).
TAIC is triallyl-1,3,5-triazine-2,4,6- (1H, 3H, 5H) -trione (CAS # 1025-15-6), also known as triallyl isocyanurate, Aldrich Chemical Company , Inc. Is marketed.
Luperox F is di (2-tert-butylperoxyisopropyl) benzene and is available from Atofina Chemicals, Inc. Marketed as LUPEROX (registered trademark) F.
VAROX is 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane on an inert filler. T.A. Vanderbilt, Company, Inc. Is marketed as VAROX (registered trademark) DBPH-50.
N990 is carbon black (CAS # 1333-86-4), Degussa
Thermal Black N99 by Engineered Carbons
It is marketed as 0.
Austin Black is carbon black, Coal Fillers I
It is marketed as Austin Black (registered trademark) by ncorporated.
ZnO is zinc oxide USP powder (CAS # 1314-1-3, CP Hall an
d the Zinc Corporation of America).
Silicone Compound A is a silicone compound, Silastic® LCS-755 silicone rubber (100 parts, marketed by Dow Corning Corporation, Midland, MI), 9330 Zinc Oxide Transparent (5 parts, marketed by Akrochem Corporation), and VAROX (0.4 parts) Main body.
EPDM is a low diene content ethylene-propylene terpolymer (EPDM) and is marketed by Dupont-Dow Elastomers, LLC as Nordel® IP NDR 3640.00.
G902 is a 1-propene-1,1,2,3,3,3-hexafluoropolymer, which is an iodine-modified fluorinated elastomer (CAS # 25190-89-0) having 1,1-difluoroethene and tetrafluoroethene. ) Daikin America, Inc. Is marketed as DAI-EL ^TM fluorinated elastomer G-902.

Test The tensile, elongation, and 100% modulus of the cured elastomer composition was measured by a procedure based on ASTM D412. A Shore A Durometer was measured by a procedure based on ASTM D 2240. Penetration was assessed by a modification of ASTM E96 using a Payne cup. The CE10 test fuel is 10% by volume of ethanol in control fuel C. CE10 was placed in the osmotic cup and a rubber septum was placed over the cup and then secured with a sealed rig lowered with a set screw. The cup was turned over to the fuel that was in direct contact with the diaphragm. Weight loss measurements were taken until the rate of penetration was constant. The permeation rate is calculated for ASTM E96 and is expressed in mm grams / m ² days using the diaphragm surface area.

Example 1
GP-50 (60 g) and Luperox F (0.2 g) were mixed on a 2 roll mill to form a silicone compound. The silicone compound (60.2 g) and EPDM (140 g) were added to a 379 mL Haake mixer equipped with a Banbury roller at 150 ° C. and 100 revolutions per minute (rpm). After about 2.5 minutes, the material was removed and placed in a 177 ° C. press for 10 minutes before the torque increase. The elastomer composition was divided into parts. 1A was further compounded as it was. 1B was heated for 16 hours / 90 ° C. and then compounded. The resulting EPDM elastomer composition (50 g) is combined with VAROX (3 g) and N990 (8 g) and Austin Black (4 g) and ZnO (2 g) on a two roll mill to make these components uniform. Until mixed.

Example 2
Without compounding, GP-50 (60 g) and EPDM (140 g) were added to a 379 mL Haake mixer equipped with a Banbury rotor at 150 ° C. and 100 revolutions per minute (rpm). After about 2.5 minutes, the elastomer blend was removed. The elastomer blend was divided into parts. 2A was further compounded as it was. 2B was heated for 16 hours / 90 ° C. and then compounded. The resulting elastomer blend (50 g) was combined with Luperox F (0.05 g), VAROX (3 g) and N990 (8 g), Austin Black (4 g) and ZnO (2 g) on a 2 roll mill, Examples A final component identical to 1 was given and mixed until these components were uniform.

  Examples 1-2 were press cured at 177 ° C. for 20 minutes. The resulting cured elastomer composition and the physical properties of the blend are summarized in Table 1.

Example 3
For sample 3A, silicone compound A (142 g) and G902 (344 g) were added to a 310 mL Haake mixer equipped with a Banbury roller at 90 ° C. and 125 revolutions per minute (rpm). This blend was removed when 130 ° C. was reached before the torque increase and was then placed in a 200 ° C. press for 10 minutes to form an FKM elastomer composition with a ML (1 + 10) of 43 at 43 ° C. Sample 3B is the same as Sample 3A, but for Sample 3B, ML at 121 ° C. is used except that the blend has reached 160 ° C. and has been reacted and then removed after 5 minutes of torque increase. An FKM elastomer composition having (1 + 10) of 67 was obtained. ZnO (3.44 parts), VAROX (2.06 parts) until the resulting FKM elastomer composition (100 parts) is uniform in the Haake and then on the mill until uniform. And TAIC (2.75 parts). The samples were pressure cured for 10 minutes at 160 ° C. and then post cured for 4 hours at 200 ° C. Sample 3A had a Shore A Durometer 60, a tensile strength of 7.39 MPa, an elongation of 320%, and a penetration of 708 mm grams / day m ² . Sample 3B had Shore A Durometer 61, a tensile strength of 9.45 MPa, an elongation of 295%, and a penetration of 2508 mm grams / m ² day.

Example 4
LS-2840 (100 parts), ZnO (5 parts), HT-1 (1 part), and Varox (0.8 parts) were mixed on a 2 roll mill to form a silicone compound. This silicone compound (257 g) and G902 (229 g) were added to a 310 mL Haake mixer equipped with a Banbury roller at 150 ° C. and 125 rev / min (rpm). For sample 4A, this blend was removed when 150 ° C. was reached before the torque rise and then placed in a 177 ° C. press for 10 minutes to form an FKM elastomer composition. For sample 4B, the blend was allowed to react in the Haake and removed after 5 minutes of torque increase.

  ZnO (2.35 parts), Varox (1.41 parts), and TAIC until the resulting FKM elastomer composition (100 parts) is uniform in the Haake and then on the mill until uniform. (1.88 parts). These samples were pressure cured for 10 minutes at 160 ° C. and then post cured for 4 hours at 200 ° C. These physical properties are listed in Table 2.

Example 5
Samples 5A and 5B were prepared similarly to Samples 4A and 4B, except that LS-2840 was replaced with LS5-2040. These physical properties are listed in Table 2.

Example 6
Samples 6A and 6B were prepared similarly to Samples 4A and 4B, except that LS-2840 was replaced with LS4-9040 and 252 g of the silicone compound was used. These physical properties are listed in Table 2.

Example 7
An FKM elastomer composition was prepared using a 25 mm Werner & Pfleiderer twin screw extruder with a processing speed of 50 ° C. and a screw speed of 300 rpm at an output speed of 20 kg / hour. This processing began with the addition of silicone compound A at a feed rate of 70 g / min, and then a fluorocarbon elastomer (G902) was added to the extruder at a feed rate of 264 g / min. This blend was extruded as shreds in a 12 foot horizontal oven set at 350 ° C. The resulting FKM elastomer composition (100 parts) is homogenized in Haake and then on the mill until uniform, ZnO (3.69 parts), Varox (2.21 parts), and TAIC ( 2.95 parts). These samples were pressure cured for 10 minutes at 160 ° C. and then post cured for 4 hours at 200 ° C., giving a Shore A Durometer 63, a tensile strength of 9.3 MPa, an elongation of 395%, and a penetration of 634 mm grams / m ² days. It was.

Claims (14)

A method for preparing an elastomer composition comprising:
(I) (A) Elastomer
(B) Optional compatibilizer
(C) any catalyst
(D) Silicone base containing curable organopolysiloxane
(E) Any cross-linking agent
(F) mixing a sufficient amount of curing agent to cure the organopolysiloxane, and then (II) statically vulcanizing the organopolysiloxane, wherein in the elastomer base composition The method wherein the weight ratio of elastomer (A) to silicone base (D) is in the range of 95: 5 to 30:70. The silicone base is:
The process according to claim 1, comprising (D ') a diorganopolysiloxane containing at least 2 alkenyl groups having 2 to 20 carbon atoms (D ") an optional reinforcing filler.   The method of claim 2, wherein the cross-linking agent is present and is an organic hydridosilicon compound.   The method of claim 3, wherein the curing agent is a platinum catalyst.   The method according to claim 1 or 2, wherein the curing agent is a free radical initiator.   The elastomer is a hydrogenated copolymer of butadiene and acrylonitrile, a terpolymer of ethylene, propylene and a diene, a copolymer of vinylidene fluoride and hexafluoropropene, a terpolymer of vinylidene fluoride, hexafluoropropene and tetrafluoroethene, Alternatively, the method of claim 1 comprising a terpolymer of vinylidene fluoride, tetrafluoroethene and perfluoromethyl vinyl ether. Compatibilizer (B) is present:
(B ¹ ) Organic compound containing two or more olefin groups (B ² ) Organic polysiloxane containing at least 2 alkenyl groups (B ³ ) At least one hydrolyzable group or at least one hydroxyl group bonded to the silicon atom Olefin functional group silane also containing (B ⁴ ) organopolysiloxane having at least one organic functional group selected from amine, amide, isocyanurate, phenol, acrylate, epoxy, and thiol group (B ⁵ ) The method according to claim 1, selected from a hydrogenating agent and any combination of (B ¹ ), (B ² ), (B ³ ), (B ⁴ ), and (B ⁵ ).   The process according to claim 1, wherein the catalyst (C) is present and is selected from organic peroxides.   The method of claim 1, wherein components (D)-(F) are first mixed to form a silicone compound.   10. A method according to any one of claims 1 to 9, wherein step I is performed in an extruder.   The method of claim 1, wherein the static vulcanization occurs by heating the resulting mixture from Step I.   A product produced by the method of any one of claims 1-11.   A cured elastomer composition prepared from the product of claim 12.   An article of manufacture comprising the cured elastomer composition of claim 13.