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WO2006066395A1 - Procede de reduction du fluage a froid d'un melange de composes de caoutchouc - Google Patents

Procede de reduction du fluage a froid d'un melange de composes de caoutchouc Download PDF

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Publication number
WO2006066395A1
WO2006066395A1 PCT/CA2005/001888 CA2005001888W WO2006066395A1 WO 2006066395 A1 WO2006066395 A1 WO 2006066395A1 CA 2005001888 W CA2005001888 W CA 2005001888W WO 2006066395 A1 WO2006066395 A1 WO 2006066395A1
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Prior art keywords
olefin
polymer
vinyl acetate
adjusted
gel content
Prior art date
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Ceased
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PCT/CA2005/001888
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English (en)
Inventor
Richard Pazur
Werner Obrecht
Bill Best
Lorenzo Ferrari
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Arlanxeo Canada Inc
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Lanxess Inc
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L15/00—Compositions of rubber derivatives
    • C08L15/005—Hydrogenated nitrile rubber
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/04—Homopolymers or copolymers of ethene
    • C08L23/08—Copolymers of ethene
    • C08L23/0846—Copolymers of ethene with unsaturated hydrocarbons containing atoms other than carbon or hydrogen
    • C08L23/0853—Ethene vinyl acetate copolymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/14—Peroxides
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2205/00—Polymer mixtures characterised by other features
    • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2205/00—Polymer mixtures characterised by other features
    • C08L2205/03—Polymer mixtures characterised by other features containing three or more polymers in a blend
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2205/00—Polymer mixtures characterised by other features
    • C08L2205/22—Mixtures comprising a continuous polymer matrix in which are dispersed crosslinked particles of another polymer
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L31/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, of carbonic acid or of a haloformic acid; Compositions of derivatives of such polymers
    • C08L31/02—Homopolymers or copolymers of esters of monocarboxylic acids
    • C08L31/04—Homopolymers or copolymers of vinyl acetate

Definitions

  • the present invention relates to a process for reducing the cold flow of a rubber compound blend including compounding at least one hydrogenated nitrile polymer, at least one olefin/vinylacetate and/or olefin/acrylate polymer with at least one precrosslinked olefin/vinyl acetate and/or olefin/acrylate.
  • the present invention also relates to a curable rubber compounds containing the rubber blend having reduced cold flow. Further, the present invention relates to shaped articles containing the rubber blend having reduced cold flow.
  • Hydrogenated nitrile rubbers prepared by the selective hydrogenation of nitrile rubber (NBR, a co-polymer comprising at least one conjugated diene, at least one unsaturated nitrile and optionally further comonomers) are specialty rubbers which have very good heat resistance, excellent ozone and chemical resistance, and excellent oil resistance.
  • HNBR high level of mechanical properties of the rubber
  • oil stators, well head seals, valve plates
  • electrical electrical
  • mechanical engineering wheels, rollers
  • shipbuilding pipe seals, couplings
  • HNBR's that have good low temperature properties.
  • Therban ® LT 2157 is a terpolymer, available from Lanxess, composed of 21 wt% acrylonitrile, acrylate, and butadiene, that has a residual double bond content (RDB) of 5.5% and a glass transition temperature (Tg) of -38° C.
  • Therban ® VP KA 8882 is similar, but differs in having an RDB of less than 0.9%, and, again, has a Tg of -38.° C.
  • WO-02/16441-A discloses a hydrogenated copolymer of an unsaturated nitrile, butadiene and isoprene, wherein the molar ratio of butadiene to isoprene is less than 3:1.
  • EP-A-O 151 691 discloses a blend of 95-5 wt.% of EVA and 5-95 wt.% of HNBR.
  • CA 2,436,742 discloses a polymer blend comprising at least one, preferably statistical, hydrogenated nitrile rubber, at least one, preferably statistical, hydrogenated nitrile terpolymer rubber, at least one, preferably binary, salt of a strong base and a weak acid comprising a group 1 metal, and at least one olefin/vinylacetate or olefin/acrylate rubber.
  • the present invention relates to a process for preparing a rubber compound blend having reduced cold flow including compounding
  • the olefin/vinyl acetate and/or olefin/acrylate polymers having a gel content and a swelling index which is adjusted with gamma radiation and wherein the radiation adjusted polymer has a gel content of 40 to 80% based on the total mass of the olefin/vinyl acetate and/or olefin/acrylate polymer and a swelling index of 20 to 80 based on the gel.
  • the present invention also relates to a process for preparing a rubber blend having reduced cold flow including compounding
  • the present invention relates to curable rubber compounds containing the rubber blend having reduced cold flow. Further, the present invention relates to a shaped article containing the curable rubber compound having reduced cold flow.
  • Rubber compound blends prepared according to the present inventive process have reduced cold flow without the deterioration of other physical properties of unvulcanized rubber compounds and vulcanized rubber compounds containing the inventive rubber blends.
  • Figure 1 graphically illustrates the processing improvements in rubber compounds wherein a precrosslinked EVM is incorporated into the compound formulation.
  • nitrile rubber As used throughout this specification, the term "nitrile rubber”, “nitrile polymer” or NBR is intended to have a broad meaning and is meant to encompass a copolymer having repeating units derived from at least one conjugated diene, at least one alpha, beta-unsatu rated nitrile and optionally further copolymerizable monomer(s).
  • nitrile terpolymer rubber or "LT-NBR” is intended to have a broad meaning and is meant to encompass a copolymer having (a) repeating units derived from at least one conjugated diene, (b) at least one alpha, beta-unsaturated nitrile, (c) repeating units derived from at least one further monomer selected from the group consisting of conjugated dienes, unsaturated carboxylic acids; alkyl esters of unsaturated carboxylic acids, alkoxyalkyl acrylates and ethylenically unsaturated monomers other than dienes and (d) optionally further copolymerizable monomer(s).
  • HNBR residual C-C double bonds
  • the conjugated diene may be any known conjugated diene preferably a C 4 - C 6 conjugated diene.
  • Preferred conjugated dienes include butadiene, isoprene, piperylene, 2,3-dimethyl butadiene and mixtures thereof. Even more preferred C 4 - C 6 conjugated dienes include butadiene, isoprene and mixtures thereof. The most preferred C 4 -C 6 conjugated diene is butadiene.
  • the alpha, beta-unsatu rated nitrile may be any known alpha, beta- unsaturated nitrile, preferably a C 3 -C 5 alpha, beta-unsatu rated nitrile.
  • Preferred C 3 - C 5 alpha, beta-unsaturated nitriles include acrylonitrile, methacrylonitrile, ethacrylonitrile and mixtures thereof.
  • the most preferred C 3 -C 5 alpha, beta- unsaturated nitrile is acrylonitrile.
  • the unsaturated carboxylic acid may be any known unsaturated carboxylic acid copolymerizable with the other monomers, preferably a C 3 -Ci 6 alpha, beta- unsaturated carboxylic acid.
  • Preferred unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid and maleic acid and mixtures thereof.
  • the alkyl ester of an unsaturated carboxylic acid may be any known alkyl ester of an unsaturated carboxylic acid copolymerizable with the other monomers, preferably an alkyl ester of an C 3 -C-
  • Preferred alkyl ester of an unsaturated carboxylic acid include alkyl esters of acrylic acid, methacrylic acid, itaconic acid and maleic acid and mixtures thereof, preferably methyl acrylate, ethylacrylate, butylacrylate, 2-ethylhexyl acrylate and octyl acrylate.
  • Preferred alkyl esters include methyl, ethyl, propyl, butyl and octyl esters.
  • the alkoxyalkyl acrylate may be any known alkoxyalkyl acrylate copolymerizable with the other monomers, preferably methoxyethyl acrylate, ethoxyethyl acrylate and methoxyethoxyethyl acrylate and mixtures thereof
  • the ethylenically unsaturated monomer may be any known ethylenically unsaturated monomer copolymerizable with the other monomers, preferably allyl glycidyl ether, vinyl chloroacetate, ethylene, butene-1 , isobutylene and mixtures thereof.
  • the HNBR according to the present invention contains in the range of from 40 to 85 weight percent of repeating units derived from one or more conjugated dienes and in the range of from 15 to 60 weight percent of repeating units derived from one or more unsaturated nitriles. More preferably, the HNBR contains in the range of from 60 to 75 weight percent of repeating units derived from one or more conjugated dienes and in the range of from 25 to 40 weight percent of repeating units derived from one or more unsaturated nitriles. Most preferably, the HNBR contains in the range of from 60 to 70 weight percent of repeating units derived from one or more conjugated dienes and in the range of from 30 to 40 weight percent of repeating units derived from one or more unsaturated nitriles.
  • the nitrile terpolymer according to the present invention is a hydrogenated alpha, beta-unsaturated nitrile/ butadiene/isoprene rubber.
  • the ratio of repeating units derived from butadiene to repeating units derived from isoprene is preferably below 3:1 , more preferably below 2:1.
  • the ratio can be as low as 0.1 :1 , but is preferably not less than 0.5:1. Good results are obtained with a ratio of 1 :1 and the preferred range is 0.75:1 to 1 :0.75.
  • the butadiene plus isoprene usually constitutes in the range of from 50 to 95% of the copolymer, and the nitrile usually constitutes in the range of from 5 to 50% of the copolymer.
  • the nitrile content does not normally exceed 36% and is preferably below 30%.
  • the preferred lower limit on the nitrile content is 15%, because copolymers with lower nitrile contents tend to lose their oil resistance. For applications where oil resistance is not of importance, however, lower nitrile contents are acceptable, down to 10% or even 5%. For most purposes a nitrile content of 15 to 25% is preferred.
  • the nitrile terpolymer rubber is a hydrogenated alpha, beta-unsaturated nitrile/butadiene/acrylate rubber.
  • the combined butadiene and acrylate content constitutes a range of 50 to 95% of the terpolymer, while the nitrile is in the range of 5 to 50%. More preferably, the nitrile range is between 10 and 30%.
  • Commercially available examples of such terpolymers include Therban® LT 2157 (21 % nitrile content, 5.5% residual double bonds) and Therban® LT VP KA 8882 (21 % nitrile content, 0.9 % maximum double bond content).
  • the hydrogenated nitrile polymer and/or the hydrogenated nitrile terpolymer rubber may further contain repeating units derived from one or more copolymerizable monomers. Repeating units derived from one or more copolymerizable monomers will replace either the nitrile or the diene portion of the nitrile rubber and it will be apparent to the skilled in the art that the above mentioned figures will have to be adjusted to result in 100 weight percent.
  • the olefin/vinylacetate polymers according to the present invention may be any olefin/vinylacetate rubber known in the art.
  • the olefin may be any known olefin, preferably ethylene, propylene, butenes, pentenes, hexenes, heptenes, octenes and their higher homologues and mixtures thereof.
  • the olefin/vinylacetate rubber usually contains in the range of from 10-95 wt.%, preferably 10-80 wt%., of repeating units derived from the olefin monomer(s) and in the range of from 5-90 wt.%, preferably 20-90 wt.%, of repeating units derived from the vinylacetate.
  • Preferred are olefin/vinylacetate rubbers available under the trade-name LEVAPREN ® from Lanxess Germany GmbH.
  • the olefin/acrylate polymer may be any olefin/ acrylate rubber known in the art.
  • the olefin may be any known olefin, preferably ethylene, propylene, butenes, pentenes, hexenes, heptenes, octenes and their higher homologues and mixtures thereof.
  • the acrylate may be any known acrylate copolymerizable with the olefin, preferably acrylic acid and derivatives such as methacrylic acid and methylmethacrylate.
  • the olefin/acrylate rubber usually contains in the range of from 5-95 wt.%, preferably 10-80 wt%., of repeating units derived from the olefin monomer(s) and in the range of from 5-95 wt.%, preferably 20-90 wt.%, of repeating units derived from the acrylate(s).
  • a precrosslinked olefin/vinylacetate and/or a precrosslinked olefin/acrylate polymer is added to a rubber blend to reduce the cold flow of the rubber blend.
  • Suitable precrosslinked olefin/vinylacetate and/or a precrosslinked olefin/acrylate polymers useful in the present invention are prepared according to United States Patent No. 6,399,671 , the contents of which are herein incorporated by reference.
  • the precrosslinked polymers in the rubber compound blend having reduced cold flow according to the present invention are those synthesized from ethylene and vinyl acetate, from ethylene and the above-stated acrylates.
  • the mixture ratio of the monomers relative to each other is conventionally 0.1%-99.9%, preferably 5%-95%, more preferably 30%-80%.
  • the gel content and degree of swelling of the precrosslinked polymers according to the present invention is established by ionizing radiation.
  • Treatment with ⁇ radiation is preferably considered as the ionizing radiation.
  • the precrosslinked polymers useful in the present invention preferably have a gel content of 30 to 80%, more preferably of 40 to 70%.
  • the swelling index is preferably 20 to 80, more preferably 40 to 60.
  • the gel content and swelling index of the precrosslinked polymers useful in the present invention are determined using the following method:
  • the sample is placed in methylene chloride, to which 1 g/l of lonol had been added, such that there were 12.5 g of polymer per liter of solvent.
  • the mixture is shaken for 6 hours at 14O 0 C, and then centrifuged for 1 hour at 20,000 rpm, wherein the temperature was still maintained at 14O 0 C.
  • the sol solution was separated and may optionally be further investigated.
  • the gel is first weighed while moist and the quantity of the dry gel obtained after drying to constant weight in a vacuum drying cabinet is determined. The percentage gel content and the swelling index are calculated using the following formulae:
  • the treatment with ionizing ⁇ radiation is performed at a radiation dose of 20 to 140, preferably of 60 to 120, more preferably of 70 to 100 kGy (kilogray). Irradiation may be performed using any desired plant suitable for this purpose, for example with a 3.5 MCi 60 Co gamma plant (approx. 1.3 MeV). Apart from Co-60 radiation, radiation from the 137 Cs isotope is also suitable.
  • the applied radiation dose may, for example, be measured using a photometric system from Far West Technology, USA and the film dosimeter supplied by this company.
  • These film dosimeters contain a radiation-sensitive dye and the radiation dose is calculated on completion of the irradiation process from the change in the absorbance of said dye. These dosimeters are calibrated ex works against an internationally recognized standard. Treatment with ⁇ radiation may be performed in the conventional manner at temperatures of 0° to 130°, preferably of 10° to 120°, more preferably of 20 to 80 0 C. The most favorable temperature range may readily be determined by appropriate preliminary testing. It is essential that the temperature range is selected such that adequate free radical mobility is ensured.
  • the precrosslinked olefin/vinylacetate and/or olefin/acrylate polymers according to the present invention are preferably produced by initially polymerizing the monomers used in a conventional manner and then treating the resultant polymers with ionizing radiation.
  • a powder mixer may also be used for homogenization. By means of this homogenization, it is possible to obtain a product which is entirely uniform with regard to gel content, irrespective of the shape and size of the irradiated container.
  • the desired average gel content may, of course, also be established by blending with non-irradiated or more or less highly irradiated polymers, i.e. with polymers having different gel contents.
  • the amount of the individual polymers and/or rubbers present in the present inventive process for preparing a rubber compound blend having reduced cold flow may vary in wide ranges and thus it is possible to tailor the properties of the final compound as well as the properties of the final shaped article.
  • the rubber blend contains in the range of from 5 to 50 wt.%, preferably from 10 to 40 wt.%, of at least one, preferably statistical, hydrogenated nitrile rubber and/or in the range of from 5 to 50 wt.%, preferably from 10 to 40wt.%, of at least one, preferably statistical, hydrogenated nitrile terpolymer rubber , and in the range of from 5 to 50 wt.%, preferably from 10to 40 wt.%, of at least one olefin/vinylacetate rubbers and/or one or more olefin/acrylate rubbers and in the range of from 20 to 80 wt.%, preferably from 30 to 70 wt.%, of at least one precrosslinked
  • the Mooney viscosity of the polymers and/or rubbers in the rubber compound blends having reduced cold flow may vary in wide ranges and thus it is possible to tailor the properties of the final compound as well as the properties of the final shaped article.
  • the hydrogenated nitrile polymer and/or hydrogenated nitrile terpolymer may have a Mooney viscosity ML(1+4@ 100 0 C) of in the range of from 20 to 100 MU, preferably 40 to 80 MU.
  • the olefin/vinyl acetate and/or olefin/acrylate polymer may have a Mooney viscosity ML (1+4@ 100 0 C) of in the range of from 10 to 90 MU, preferably 20 to 70 MU.
  • the precrosslinked olefin/vinyl acetate and/or olefin/acrylate polymer may have a Mooney viscosity ML (1+4@ 100 0 C) of in the range of from 30 to 90 MU, preferably 40 to 70 MU
  • the Mooney viscosity of the raw polymers, the rubber compound blend and the cured rubber compound containing the inventive rubber compound blend having reduced cold flow can be determined using ASTM test D1646.
  • the present inventive rubber compound blend may further contain up to 30 wt% of other polymers such as polyolefins, BR (polybutadiene), ABR (butadiene/acrylic acid-Ci-C ⁇ alkylester-copolymers), CR
  • a rubber compound blend having reduced cold flow is prepared by compounding at least one, preferably statistical, hydrogenated nitrile polymer and/or hydrogenated nitrile terpolymer, at least one olefin/vinyl acetate and/or olefin/acrylate polymers with at least one olefin/vinyl acetate and/or olefin/acrylate polymers having a gel content and a swelling index which is adjusted with gamma radiation and wherein the radiation adjusted polymer has a gel content of 40 to 80% based on the total mass of the olefin/vinyl acetate and/or olefin/acrylate polymer and a swelling index of 20 to 80 based on the gel, at a temperature in the range of between 75 to 175°C to form a rubber blend having reduced cold flow.
  • at least one filler and vulcanizing agent has
  • Suitable filler(s) may be an active or an inactive filler or a mixture thereof.
  • the filler(s) may be in particular: - highly dispersed silicas, prepared e.g. by the precipitation of silicate solutions or the flame hydrolysis of silicon halides, with specific surface areas of in the range of from 5 to 1000 m 2 /g, and with primary particle sizes of in the range of from 10 to 400 nm; the silicas can optionally also be present as mixed oxides with other metal oxides such as those of AI, Mg, Ca, Ba, Zn, Zr and Ti;
  • silicates such as aluminum silicate and alkaline earth metal silicate like magnesium silicate or calcium silicate, with BET specific surface areas in the range of from 20 to 400 m 2 /g and primary particle diameters in the range of from 10 to 400 nm;
  • silicates such as kaolin and other naturally occurring silica
  • metal oxides such as zinc oxide, calcium oxide, magnesium oxide and aluminum oxide
  • - metal carbonates such as magnesium carbonate, calcium carbonate and zinc carbonate
  • - metal hydroxides e.g. aluminum hydroxide and magnesium hydroxide
  • the carbon blacks to be used here are prepared by the lamp black, furnace black or gas black process and have preferably BET (DIN 66 131) specific surface areas in the range of from 20 to 200 m 2 /g, e.g. SAF, ISAF, HAF, FEF or GPF carbon blacks; - rubber gels, especially those based on polybutadiene, butadiene/styrene copolymers, butadiene/acrylonitrile copolymers and polychloroprene;
  • - large aspect ratio nanoclays such as Cloisite® or mixtures thereof.
  • preferred mineral fillers include silica, silicates, clay such as bentonite, gypsum, alumina, titanium dioxide, talc, mixtures of these, and the like.
  • the preferred mineral is silica, especially silica made by carbon dioxide precipitation of sodium silicate.
  • Dried amorphous silica particles suitable for use in accordance with the invention may have a mean agglomerate particle size in the range of from 1 to 100 microns, preferably between 10 and 50 microns and most preferably between 10 and 25 microns. It is preferred that less than 10 percent by volume of the agglomerate particles are below 5 microns or over 50 microns in size.
  • a suitable amorphous dried silica moreover usually has a BET surface area, measured in accordance with DIN (Deutsche Industrie Norm) 66131 , in the range from 50 and 450 square meters per gram and a DBP absorption, as measured in accordance with DIN 53601 , in the range from 150 and 400 grams per 100 grams of silica, and a drying loss, as measured according to DIN ISO 787/11 , of in the range of from 0 to 10 percent by weight.
  • Suitable silica fillers are available under the trademarks HiSil® 210, HiSil® 233 and HiSil® 243 from PPG Industries Inc. Also suitable are Vulkasil® S and Vulkasil® N, from Bayer AG.
  • carbon black is present in the polymer blend in an amount of in the range of from 20 to 200 parts by weight, preferably 30 to 150 parts by weight, more preferably 40 to 100 parts by weight.
  • carbon black and mineral filler in the inventive rubber compound. In this combination the ratio of mineral fillers to carbon black is usually in the range of from 0.05 to 20, preferably 0.1 to 10.
  • the present curable rubber compound containing the inventive rubber compound blend having reduced cold flow may further contain a carbodiimide, a polycarbodiimide or mixtures thereof.
  • the preferred carbodiimide is available commercially under the tradenames RhenogranTM PCD-50 and StabaxolTM P.
  • This ingredient may be used in the present curable rubber compound in an amount in the range of from 0 to about 15 parts by weight, more preferably in the range of from 0 to about 10 parts by weight, even more preferably in the range of from about 2 to about 5 parts by weight.
  • the rubber compound having reduced cold flow may further contain at least one vulcanizing agent or curing system.
  • the present invention is not limited to a special curing system; however, peroxide curing system(s) are preferred.
  • the invention is not limited to a special peroxide curing system.
  • inorganic or organic peroxides are suitable.
  • Preferred peroxides include organic peroxides such as dialkylperoxides, ketalperoxides, aralkylperoxides, peroxide ethers, peroxide esters, such as di-tert.-butylperoxide, bis-(tert.- butylperoxy-isopropyl)-benzene, dicumylperoxide, 2,5-dimethyl-2,5-di(tert.- butylperoxy)-hexane, 2,5-dimethyl-2,5-di(tert.-butylperoxy)-hexene-(3), 1 ,1-bis- (tert.-butylperoxy)-3,3,5-trimethyl-cyclohexane, benzoylperoxide, tert.-butylcumyl- peroxide and tert.-
  • the amount of neat peroxide in the cured rubber compound containing the rubber blend having reduced cold flow is in the range of from 1 to 6 phr, preferably from 1 to 3 phr.
  • Subsequent curing is usually performed at a temperature in the range of from 100 to 200 0 C, preferably 130 to 180 0 C.
  • the rubber compound blend having improved cold flow according to the invention can contain further auxiliary products for rubbers, such as reaction accelerators, vulcanizing accelerators, vulcanizing acceleration auxiliaries, antioxidants, foaming agents, anti-aging agents, heat stabilizers, light stabilizers, ozone stabilizers, plasticizers, processing aids, tackifiers, blowing agents, dyestuffs, pigments, waxes, extenders, organic acids, inhibitors, metal oxides, and activators such as triethanolamine, polyethylene glycol, hexanetriol, etc., which are known to the rubber industry.
  • the rubber aids are used in conventional amounts, which depend inter alia on the intended use. Conventional amounts are e.g. from 0.1 to 50 phr.
  • the ingredients of the curable rubber compound (the rubber blend, at least one vulcanizing agent and at least one filler) are often mixed together, suitably at an elevated temperature that may range from 25 0 C to 200 °C.
  • the mixing time does not exceed one hour and a time in the range from 2 to 30 minutes is usually adequate.
  • the mixing of the rubbers, optionally the filler(s), optionally vulcanization agent, and/or further ingredients is suitably carried out in an internal mixer such as a Banbury mixer, or a Haake or Brabender internal mixer.
  • Encyclopedia of Polymer Science and Engineering Vol. 4, p. 66 et seq. (Compounding) and Vol. 17, p. 666 et seq. (Vulcanization).
  • the rubber compound blend having reduced cold flow and the curable rubber compound according to the present invention are very well suited for the manufacture of a shaped article, such as a seal, hose, bearing pad, stator, well head seal, valve plate, cable sheathing, wheel roller, pipe seal, in place gaskets or footwear component. Furthermore, they are very well suited for wire and cable production.
  • Carbon black N774 and N990 are both available from Cabot Corp..
  • ElastomagTM 170 Powder is magnesium oxide available from Morton International.
  • NaugardTM 445 is p-dicumyl diphenylamine and is available through Crompton Corp..
  • PlasthallTM TOTM is a trioctyl trimellitate from The CP. Hall Co., Inc..
  • RhenogranTM PCD-50 is a polycarbodiimide from Rhein Chemie Corp.
  • Stearic Acid EmersolTM 132 NF is stearic acid available from Acme- Hardesty Co..
  • TP-759 is an ether/ester based plasticizer available from Morton International.
  • VulkanoxTM ZMB-2/C5 is the zinc salt of 4- and 5-methyl mercaptobenzimidazole (ZMMBI) and is available from Bayer AG.
  • Zinc Oxide (KadoxTM 920) is available from St. Lawrence Chem. Inc.
  • TAIC-DLC-A is triallyl isocyanurate (72% by weight) on a silicon dioxide carrier available from Natrochem, Inc..
  • VulcupTM 40KE is a bis 2-(t-butyl-peroxy) diisopropylbenzene (40% on
  • the mixing of the compounds ingredients given in Table 1 was completed in two stages.
  • an internal BR-82 Banbury mixer with tangential rotors turning at 77 rpm was used.
  • the mixing chamber had a volume of 1.6 liters and the water was set for cooling at 30 0 C.
  • the Levapren® and Therban® polymers were added to the mixing chamber and allowed to mix for 1 minute.
  • the carbon black, magnesium oxide, antioxidants (diphenylamine, ZMMBI and polycarbodiimide), TOTM and TP-759 plasticizers, stearic acid and zinc oxide were all added to the mixer. Mixing continued for another 2 minutes.
  • the compound Mooney viscosity was determined at 100 0 C using a large rotor.
  • the sample was preheated within the rotor cavity for one minute and then, subjected to the shearing action of the viscometer disk rotating at 2 rpm for a period of 4 minutes.
  • the torque in Mooney units was immediately recorded at that time.
  • the sample was then allowed to relax for a period of 4 minutes in order to acquire information about the relaxation behavior of the rubber compound.
  • the slope, intercept and area under the relaxation curve were all recorded. The tests were compliant with ASTM D-1646.
  • Rubber Process Analyzer An RPA 2000 test devise was used to assess the processing behavior of the rubber samples. A frequency sweep was carried out on the unvulcanized rubber samples using a strain of 7% with the platen temperatures set at 100 0 C.
  • a Moving Die Rheometer (MDR 2000(E)) was used in order to follow the vulcanization behavior of the rubber samples. The platens were set at 180 0 C and a frequency of oscillation of 1.7 Hz coupled with a 1 ° arc were applied to the sample for a time of 30 minutes. This test procedure complies with ASTM D-
  • Hardness Hardness measurements were carried out according to ASTM D-2240 using an A-2 type durometer at 23 0 C.
  • Die B and die C geometries were cut out of a tensile sheet which was cured for 12 minutes at 180°C. The test complies with ASTM D-624.
  • buttons were prepared by curing the rubber samples 17 minutes at 180°C. Afterwards, the buttons are compressed 25% in a compression set jig and placed in a hot air oven set at 150 0 C for 168 hours. The test procedure complies with ASTM D-395 (Method B). Stress Strain Hot Air Aging
  • Hot air aging of the die C cut tensile samples was carried out in a hot air oven set at 150 0 C for a period of 168 hours. Testing was completed in compliance with ASTM D-573.
  • the compound Mooney viscosity data in Table 2 illustrate higher compound Mooneys for Examples 1 , 3 and 5 versus 2, 4 and 6.
  • the Mooney relaxation data demonstrate slower relaxation times for the rubber compounds containing the precrosslinked EVM.
  • the physical property data in Table 4 illustrates that the hardness does decrease upon replacement of the pre-crosslinked EVM by the standard EVM (compare Ex. 2 to Ex. 1 , Ex.4 to Ex. 3 and Ex. 6 to Ex. 5). Ultimate tensile and elongation are slightly improved upon using precrosslinked EVM. The moduli values clearly demonstrate a slight loss in overall stiffness in compounds containing the precrosslinked EVM. This fact is supported by the hardness results.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

La présente invention concerne un procédé visant à réduire le fluage à froid d’un mélange de polymères, ledit procédé comprenant le mélangeage : (I) d’au moins un caoutchouc de nitrile hydrogéné ou caoutchouc de terpolymère de nitrile hydrogéné et (ii) d’au moins un polymère oléfine/acétate de vinyle et/ou oléfine/acrylate avec (iii) au moins un polymère oléfine/acétate de vinyle et/ou oléfine/acrylate dont on ajuste par irradiation gamma la teneur en gel et l’indice de gonflement. Le polymère irradié a une teneur en gel de 40 à 80 %, rapportée à la masse totale de polymère oléfine/acétate de vinyle et/ou oléfine/acrylate, et un indice de gonflement de 20 à 80 rapporté au gel. Des compositions de caoutchouc durcissables préparées selon le procédé sont utiles sous la forme d’articles façonnés tels que joint, bague d’étanchéité, courroie, flexible, patin, stator, joint de tête de puits, plaque porte-clapet, gaine de câble, galet, joint statique ou joint d’étanchéité de tube.
PCT/CA2005/001888 2004-12-20 2005-12-13 Procede de reduction du fluage a froid d'un melange de composes de caoutchouc Ceased WO2006066395A1 (fr)

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US60/637,500 2004-12-20

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2075282A1 (fr) * 2007-12-31 2009-07-01 Bridgestone Corporation Procédé pour améliorer la résistance au fluage à froid de polymères
US7968620B2 (en) 2006-05-09 2011-06-28 Alliant Techsystems Inc. Rocket motors incorporating basalt fiber and nanoclay compositions and methods of insulating a rocket motor with the same
US8505432B2 (en) 2010-09-10 2013-08-13 Alliant Techsystems, Inc. Multilayer backing materials for composite armor
WO2015193920A3 (fr) * 2014-06-20 2016-03-31 Zenith Industrial Rubber Products Pvt. Ltd. Caoutchouc pré-réticulé et procédé pour sa fabrication
US9850353B2 (en) 2010-09-10 2017-12-26 Orbital Atk, Inc. Articles and armor materials incorporating fiber-free compositions and methods of forming same
CN110041585A (zh) * 2019-04-26 2019-07-23 无锡二橡胶股份有限公司 一种纺制涤纶长丝的高速化纤导丝辊的生产配方
CN119994002A (zh) * 2025-01-24 2025-05-13 北京中科睿升新材料有限公司 一种含有交联氢化丁腈橡胶粘结剂的锂电池极片及其制备方法

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CA2436742A1 (fr) * 2003-06-26 2004-12-26 Bayer Inc. Melanges de polymeres contenant du caoutchouc nitrile

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7968620B2 (en) 2006-05-09 2011-06-28 Alliant Techsystems Inc. Rocket motors incorporating basalt fiber and nanoclay compositions and methods of insulating a rocket motor with the same
EP2075282A1 (fr) * 2007-12-31 2009-07-01 Bridgestone Corporation Procédé pour améliorer la résistance au fluage à froid de polymères
US8138248B2 (en) 2007-12-31 2012-03-20 Bridgestone Corporation Method to improve cold flow resistance of polymers
US8505432B2 (en) 2010-09-10 2013-08-13 Alliant Techsystems, Inc. Multilayer backing materials for composite armor
US9850353B2 (en) 2010-09-10 2017-12-26 Orbital Atk, Inc. Articles and armor materials incorporating fiber-free compositions and methods of forming same
WO2015193920A3 (fr) * 2014-06-20 2016-03-31 Zenith Industrial Rubber Products Pvt. Ltd. Caoutchouc pré-réticulé et procédé pour sa fabrication
CN110041585A (zh) * 2019-04-26 2019-07-23 无锡二橡胶股份有限公司 一种纺制涤纶长丝的高速化纤导丝辊的生产配方
CN110041585B (zh) * 2019-04-26 2021-09-10 无锡二橡胶股份有限公司 一种纺制涤纶长丝的高速化纤导丝辊的生产配方
CN119994002A (zh) * 2025-01-24 2025-05-13 北京中科睿升新材料有限公司 一种含有交联氢化丁腈橡胶粘结剂的锂电池极片及其制备方法

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