AEROSIL® for Silicone Rubber - Adhesives & Sealants by Evonik

AEROSIL ® –More than just a powderDr. Harry Kloepfer,Evonik chemistand inventor ofAEROSIL ® fumed silicaEvonik Industries developed AEROSIL ®fumed silica more than 60 years ago, andhas dominated the world’s developmentand production of fumed silica ever since.The silicone industry as we know it wouldbe inconceivable without fumed silica.AEROSIL ® products allow optimaladjustment of the rheological propertiesfor every individual application andimprove mechanical properties; moreover,AEROSIL ® fumed silica also acts as ananti-sedimentation agent and improvesthe storage stability, processability andapplication of silicone materials. SpecialAEROSIL ® grades allow systems to berealized that are highly transparent orparticularly stable to heat. It is not justAEROSIL ® fumed silica that has becomeindispensable; the highly specialized andenvironmentally friendly technologiesthat it has spawned have also becomefirmly established in the silicone industry.In addition to the actual AEROSIL ®products, we offer in many cases acomplete technological solution withunbeatable advantages. Our specializedteams in Research and Development worktowards continued development of theproducts and their applications.Dedicated laboratories work outapplications and handling solutions inconjunction with customers. Highlyefficient logistics guarantee on-timedelivery. Well-designed packaging solvestechnical handling problems before theycan occur. Technical support and customercare are available worldwide. A policyof long-term availability means thatAEROSIL ® fumed silica offers planningsecurity and avoids unexpected investmentcosts for alternative solutions.Our worldwide presence allows us topool our expertise in an internationalnetwork. We work hand in hand with ourcustomers to develop individual systemsolutions that meet their highest standardsand make their silicone products evenmore successful.3

For us, the highest degree of customersatisfaction is not an elastic conceptAEROSIL ® fumed silicaimparts high mechanicalstrength and anti-slipproperties to siliconecoatedtextilesYears of expertise in solutionsSilicone Rubber is used in the most variedindustries, and is becoming increasinglyimportant particularly in the automotiveand textile industries. The developmentof special hydrophobic AEROSIL ® gradeshas allowed production of modernadhesives and sealants that are helpingshape the technologies of the future inautomotive production. With thesemodern Silicone Sealants, it is possible touse structural glazing for light-transparentroof and facade structures. Silicone-coatedfabrics, in contrast, are used not only intechnical fields, such as textile structuralapplications, but also find interestingapplication in other products. In siliconecoatedtextiles such as baby socks,for example, Silicone Rubber is used that,thanks to the AEROSIL ® reinforcingcomponent, provide a coating of highmechanical strength with anti-slipproperties. Coatings of this type alsorepel dirt and water.4

AEROSIL ® milestones for the silicone industryMarket Introduction1940s1960s1970s1980s1990sTodayAEROSIL ® grades / new productsDevelopment of the world’s first hydrophilicfumed silicas, e.g. AEROSIL ® 150, 200, 300AEROSIL ® R 972: Development of theworld’s first hydrophobic fumed silicamodified with dichlorodimethyl silane (DDS)AEROXIDE ® TiO2 P 25:Development of a fumed titanium dioxideAEROSIL ® R 812 S: Development of ahighly hydrophobic fumed silica modifiedwith hexamethyldisilazane (HMDS)AEROSIL ® R 104, R 106: Developmentof hydrophobic fumed silicas modifiedwith octamethyl cyclotetrasiloxane (D4)AEROSIL ® R 8200: Development of astructure modified, highly hydrophobic fumedsilica modified with hexamethyldisilazane(HMDS)AEROSIL ® 200 SP, AEROSIL ® 300 SP –Development of a structure modifiedhydrophilic fumed silicaApplicationsAcetoxy crosslinking RTV one-componentSilicone Sealants and high-temperaturevulcanizing Silicone Rubber (HTV)Neutrally crosslinking RTV one-componentSilicone Sealants (alcoxy and oxime systems)Heat stabilizer for all Silicone Rubber systemsHighly transparent, high-temperaturevulcanizing liquid Silicone Rubber(LSR/LIMS)Highly transparent, high-temperaturevulcanizing Silicone Rubber (HTV)Self-leveling RTV one-componentSilicone SealantsRTV two-component casting compoundsand molding compoundsHighly transparent, easy processing SiliconeRubber (HTV and LSR/LIMS)Extremely wide product range, noveland innovative experimental productsWith a number of AEROSIL ® gradesdeveloped specially for the siliconeindustry, Evonik can offer a product rangeproviding technical advantages andimprovements for a large number ofsilicone systems. And it already has abroad base of novel and innovativeexperimental products for developmentof the next generation of AEROSIL ®products.These novel products will allowcontinued improvement of various highlyinteresting properties in Silicone Rubbersuch as flowability, tear resistance, andtransparency.5

AEROSIL ® – Advantageousfor thermal propertiesFood molds made fromSilicone Rubber retain theirgreat flexibility not only attemperatures down to-40 °C (ice-cube trays)but also above 200 °C(cake molds)AEROSIL ® in flexible and temperaturestablefood moldsAEROSIL ® fumed silica plays an importantrole as an active reinforcing component infood molds made of Silicone Rubber, suchas ice-cube trays or cake molds. Excellentthermal properties such as low-temperatureflexibility and heat resistance are obtainedby the use of AEROSIL ® products orspecial heat stabilizers.Silicone Rubber ice-cube trays retain theirflexibility even at temperatures as low as-40 °C, making it very easy to remove theice cubes from the tray without damagingit. Cake molds of Silicone Rubber, on theother hand, are heat-resistant up to 280 °C,non-slip and completely dishwasher safe.No non-stick coating or greasing of themold is necessary because the batter doesnot adhere to the elastic silicone mold.And the silicone material results in energysavings of 10 –20%. Food molds can bemade from solid or liquid silicones, whichmay be ready-to-use HTV or LSR SiliconeRubber. These are one-component ortwo-component systems of a highlyviscous or free-flowing consistency, whichare fully cured to an elastic SiliconeRubber under the action of speciallytailored crosslinker-catalyst systems atprocessing temperatures above 100 °C.AEROSIL ® fumed silica imparts thenecessary rheological, mechanical andoptical properties to the Silicone Rubber.Evonik offers a special oxide for SiliconeRubber, AEROXIDE ® TiO 2P 25 as a heatstabilizer for high-temperatureapplication.AEROSIL ® in and around the automobileSilicone systems such as silicone sealantswith AEROSIL ® fumed silica as activecomponent are now indispensable also inautomotive construction. Whether in theengine, the drive system, the cooling system,the electronics or the body, silicones,6

AEROSIL ® – Advantageousfor optical propertiesAEROSIL ® offers farmore than an attractiveappearance• Transparency• Smooth, glossy surfaces• Matting of surfacesRTV one-componentSilicone Sealants arereinforced withAEROSIL ® fumed silica;they are usuallypigmented but may alsobe highly transparent,glossy or mattSpecial effects: matting ofsilicone surfacesMatting of Silicone Sealants is of interestin certain application areas for safetyreasons (to provide an anti-glare effect)as well as for esthetic purposes. Inelectronic LED displays, for example,matting suppresses disturbing reflectanceof light. Conventional matting agentscannot be used in silicone sealantsbecause their water content is too high.Moreover, the large quantities of thesesubstances necessary to achieve a mattingeffect would adversely affect themechanical properties. Evonik’s VPAEROPERL ® R 806/30 is a novelsynthetic silica, developed specifically forRTV one-component Silicone Sealants,achieving significant matting even whenused in small quantities.AEROSIL ® lets you keep thingsin viewThanks to AEROSIL ® fumed silica,Silicone Rubber is colorless and highlytransparent. This has resulted in thematerial being used in a wide range ofapplications on purely esthetic grounds.Silicone Rubber can be pigmented toalmost any color, but highly transparentformulations are also commerciallyavailable. These are used for medicalapplications, such as tubes and catheters,but are also preferred in products for dailyuse such as nipples for baby bottles anddiving goggles because they allow visualchecking.The transparency of such formulations iscontrolled essentially by two factors: theparticle size of the silica and the refractive8

Highly transparentdiving goggles andsnorkel mouthpieces ofHTV Silicone Rubberindex of the polymer or filler. AEROSIL ®grades such as AEROSIL ® 300 SP havinga relatively high active surface area areespecially suitable for highly transparentsilicone systems. By modifying the fumedsilica surface with silanes or silicones, therefractive index can be adjusted so that itis similar to that of Silicone Rubber,improving the transparency of the siliconesystem.Matting effect of surfacesABAEROSIL ® R 106 and AEROSIL ® R 812 Sare examples of extremely hydrophobicmaterials that allow high-transparencyproducts.(A) Conventional sealant with AEROSIL ® products (glossy surface)(B) Sealant with AEROSIL ® fumed silica and VP AEROPERL ® R 806/30 (matt surface)9

AEROSIL ® – Advantageousfor rheological propertiesWith AEROSIL ® it’sguaranteed to flowperfectly – or not at all• Viscosity• Extrusion rate• Thixotropic effect• Flowability• Storage stabilitySilicone Rubber and AEROSIL ® –without thickening?In addition to their reinforcing effect,fumed silicas such as AEROSIL ® fumedsilica in particular have thickeningand thixotropic properties that aredisadvantageous in a number ofapplications and must therefore besuppressed. This is especially important invery low-viscosity and free-flowingsystems such as Liquid Silicone Rubber(LSR) and RTV two-component systems(casting and molding compounds). Lowviscosities are essential here, and not onlyfor ease of processing: fairly long storageperiods, without significant changes inthe rheological properties, must beguaranteed for these sensitive systems.By modification of hydrophilic startingproducts in special processes, Evonikcan offer highly hydrophobic (e.g.AEROSIL ® R 812 S) and even highlyhydrophobic structurally modifiedproducts (e.g. AEROSIL ® R 8200) thatsatisfy these exacting requirements.Silicone Rubber deliberately thickened– thanks to AEROSIL ® !Other silicone systems, on the other hand,require certain levels of viscosity, whichcan be set selectively by the use of afumed silica. When processing RTV onecomponentSilicone Sealants, for example,a particular extrusion rate (extrudability)is absolutely essential.The attainment of a particular viscositylevel (yield point) is also essential so thatthe sealant remains in the desired locationin the application (e.g. in a wall joint) andis fully cured at exactly that location. Thiseffect that AEROSIL ® fumed silica providesis known as thixotropy.In general, hydrophilic AEROSIL ® productsof moderate active surface area such asAEROSIL ® 150 are used for RTV onecomponentSilicone Sealants. Hydrophobicproducts like AEROSIL ® R 106 andAEROSIL ® R 812 S with higher activesurface areas are excellently suited forhighly transparent systems.(left) Structurally modified,hydrophobic AEROSIL ® R 8200for low-viscosity, free-flowingRTV two-component Silicone Rubber(middle) RTV two-componentSilicone Rubber finds application inmonument preservation (moldingcompounds), in dental technology,and for rapid prototyping ofcomponents in, e.g., the automotiveindustry(right) RTV one-component SiliconeSealant before hardening in a seal(left) without AEROSIL ® products(right) with AEROSIL ® fumed silica asthixotropic agent10

Processing of RTV onecomponentSiliconeSealants, e.g. for sealingshowers11

AEROSIL ® – Advantageousfor mechanical properties(left) AEROSIL ® fumedsilica is used as areinforcing componentin Silicone Rubberproducts for earthquakeproofbuilding foundations(right) Tensile testingmachine for determinationof mechanical propertiessuch as tensile strength,elongation at break, andtear resistance of curedSilicone RubberAEROSIL ® – in earthquake-proofbuilding foundationsSilicone Rubbers with AEROSIL ® fumedsilica as the active reinforcing componentplay an important role in earthquakeprooffoundations. The Japanesedevelopedtechnology of using SiliconeRubber as an important component offoundations affords buildings in particularlyendangered regions additional protectionagainst earthquake damage, even underlarge mechanical stress.For this purpose, conventional buildingmaterials are combined in a specialprocess with layers of Silicone Rubber forwhich the parameters have previouslybeen calculated with high precision.RTV two-component Silicone Rubber isused not only for sealing purposes in thisapplication, but also to provide thefoundation with a special elasticity at bothhigh and low temperatures. RTV twocomponentSilicone Rubber is a readyto-usetwo-component systems of afree-flowing or slightly pasty consistency,which, under the action of crosslinkercatalystsystems tailored specifically tothese systems, are cured at roomtemperature to an elastic Silicone Rubber.AEROSIL ® fumed silica imparts to theSilicone Rubber the required rheologicaland mechanical properties.12

Our Technical Handling Service Offersour Concentrated Expertise(right) AEROSIL ®fumed silica in a semibulk container (FIBC:Flexible IntermediateBulk Container)(left) Typical bagpackaging of EvonikAEROSIL ® fumed silicaWorking with AEROSIL ®At a time when automation, rationalization, industrial hygiene forthe protection of employees and environmental regulations arebecoming increasingly important, so also is the subject of thehandling of AEROSIL ® products. For more than 10 years now,AEROSIL ® fumed silica has been expanding its activities in this areaconcurrently with this development.Basic product knowledge and process-engineering experience inhandling fumed oxides are necessary for planning dust-freeautomated plants for AEROSIL ® products. We offer our customersour expertise in this area for the solution of specific problems. In thisway we jointly develop concepts that simplify the handling ofAEROSIL ® fumed silica for our customers.HandlingThe term „handling“ describes thetechniques required to move AEROSIL ®fumed silica within a customer’s plant.The following are the most importantconsiderations here:• emptying of packaging units• silo storage• internal conveying• dosing• feeding materials into themanufacturing processIn addition, the term „handling“ alsocovers the activities necessary to executethe above steps. Your local customerservice agent will be happy to providefurther details of this service offer.14

Dust-free automatedconveying systemPackagingAEROSIL ® fumed silica in powder formis available in three different forms ofpackaging. The standard packaging is themulti-layer paper bag, which is in somecases provided with an polyethylenecoating on one layer. The net weights ofthe bags, of between 10 and 20 kg,depend on the AEROSIL ® grade and alsoon the set tapped density. Evonik offersAEROSIL ® fumed silica also in FIBC(Flexible Intermediate Bulk Containers) asa form of semi bulk packaging. Hereagain, filling quantities vary depending onthe product and its densification. Anotherpossibility, for bulk usage, is purchase insilo trucks, which requires the customerto have an appropriate storage silo.The AEROSIL ® fumed silica dispersionsknown as AERODISP ® are supplied in60 kg drums, 220 kg barrels and 1000 kgIBCs (intermediate bulk containers).Storage stabilityAEROSIL ® fumed silica is chemically inertto a large extent, and under suitablestorage conditions undergoes no chemicalchanges even over fairly long storageperiods. It must be noted, however, that afew substances react with silicon dioxide.On account of the high specific surfacearea, volatile substances may be adsorbedat the surface of AEROSIL ® products. Inthe case of water vapor this adsorption isreversible. Organic modification ofhydrophobic AEROSIL ® grades significantlyreduces the ability of these products toadsorb water vapor.AEROSIL ® products may become slightlycompacted over long storage periods.This may lead to a slight increase in thetapped density and affect the associatedproduct properties.15

The Advantage of a Global Enterprise –Local ProximityAEROSIL ® fumed silicain the world: more than100 sales offices in95 countries, 8 productionsites and a number ofapplied technology servicecenters are located in Asia,America and Europe.Size usually creates distance – but not atEvonik. As a leading specialty chemicalscompany Evonik relies on the businessphilosophy: „as decentralized as possible,as centralized as necessary“.The decentralized organization at alllevels and in all divisions of the companyis tailored to operative units which canrespond to the market quickly, flexiblyand on a customer-oriented basis. As abrand operating worldwide, AEROSIL ®uses production facilities, applicationrelatedservice centers, research centersand commercial and technical serviceoffices in all regions of the world.The mere fact that we produce on3 continents represents a decisive advantagefor us and our customers when it comesto an effective world-wide delivery16

service. With a total of more than1200 motivated employees and morethan 100 service offices in 95 countries,we also offer our customers the biggestservice network of all suppliers on themarket.The combination of highest productquality and a marked focus on service andconsulting is a major cornerstone of theAEROSIL ® strategy. As a brand that isactive worldwide we also want tocombine with partners to form a strong,international network in which weconcentrate our areas of expertise.A functioning globality, which ourcustomers experience on a local level.Always close by.17

Technical LiteratureFor detailed informationon our technical bulletins and for downloads pleasevisit our Internet Service Center at www.aerosil.com,or write to:Evonik Degussa GmbHBusiness Line Rubber ReinforcementWeißfrauenstr. 9D-60287 Frankfurt/Main, GermanyPhone +49 69/218-53 17Fax +49 69/218-35 41E-Mail: siliconerubber@evonik.comwww.aerosil.comBrochure Product Overview• AEROSIL ® Product Overview• Dynasylan ® Product OverviewIndustry Brochure Adhesives and Sealants• AEROSIL ® and Silanes for Adhesivesand SealantsIndustry Information No. 2123• AEROSIL ® in Adhesives and SealantsTechnical Bulletin Pigments No. 11• Basic Characteristics of AEROSIL ® fumed silicaTechnical Bulletin Pigments No. 12• Evonik Silicas for HTV Silicone RubberTechnical Bulletin Pigments No. 28• Handling of Synthetic Silicas and SilicatesTechnical Bulletin Pigments No. 63• Synthetic Silicas for SealantsTechnical Information No. 1148• AEROSIL ® R 104 and AEROSIL ® R 106for Silicone Rubber ApplicationsTechnical Information No. 1151• AEROSIL ® VV for Silicone Rubber ApplicationsTechnical Information No. 1209• AEROSIL ® R 8200 for Silicone RubberTechnical Information No. 1253• AEROSIL ® and AEROXIDE ®for Liquid Silicone Rubber (LSR/LIMS)Technical Information No. 1349• Structure modified AEROSIL ® fumed silicafor the Silicone Rubber Industry18

Solutions for the Silicone Rubber IndustryRoom Temperature VulcanisationHeat Cured SystemEffectsSystemsOne pack systemRTV 1-CSilicone SealantsTwo pack systemRTV 2-CCasting and moldingcompoundsHeat cured rubberHTVPress vulcanization andextrusion articlesLiquid silicone rubberLSRInjection moldedarticlesControl of rheologicaland mechanicalpropertiesThixotropic effect,flow properties andreinforcing actionAEROSIL ® 130AEROSIL ® 150AEROSIL ® R 972AEROSIL ® R 8200AEROSIL ® 200AEROSIL ® 300AEROSIL ® R 812 SAEROSIL ® R 8200SIPERNAT ® 120SIPERNAT ® 320 DSSIPERNAT ® D 17AEROSIL ® 200/VAEROSIL ® 300/VAEROSIL ® 380AEROSIL ® R 104SIPERNAT ® 160SIPERNAT ® D 17AEROSIL ® 300AEROSIL ® 380AEROSIL ® R 812 SAEROSIL ® R 8200SIPERNAT ® 160SIPERNAT ® 120SIPERNAT ® 320 DSSIPERNAT ® D 17Control of opticalpropertiesTransparency/Pigmentation (black)AEROSIL ® R 974AEROSIL ® R 106AEROSIL ® R 812 SAEROSIL ® 200 SPAEROSIL ® 300 SPAEROSIL ® R 812 SAEROSIL ® R 8200LAMP BLACK 101 *PRINTEX ® 60AEROSIL ® 200 SPAEROSIL ® 300 SPAEROSIL ® 380AEROSIL ® R 106PRINTEX ® 300PRINTEX ® P **AEROSIL ® 300 SPAEROSIL ® 380AEROSIL ® R 812 SAEROSIL ® R 8200PRINTEX ® alpha **Improvement ofheat stabilityAEROXIDE ® TiO 2P 25AEROXIDE ® TiO 2P 25LAMP BLACK 101 *AEROXIDE ® TiO 2P 25PRINTEX ® 300AEROXIDE ® TiO 2P 25PRINTEX ® alpha **MattingVP AEROPERL ® R 806/30Electrical conductive/AntistaticPRINTEX ® P**PRINTEX ® L 6PRINTEX ® XE 2/XE 2-BPRINTEX ® alpha **Improved shelf lifeImprovementAdhesionImprovementAdhesionCross LinkerDynasylan ® VTMO ***Dynasylan ® 6490Dynasylan ® BDAC(acetoxy system)Dynasylan ® AMEODynasylan ® TRIAMODynasylan ® MEMODynasylan ® GLYMODynasylan ® DAMODynasylan ® 1146(oxyme andalkoxy system)Dynasylan ® VTMODynasylan ® VTEODynasylan ® MTMS(alkoxy system)Dynasylan ® PDynasylan ® ADynasylan ® 40(condensations cured)In-situ surfacetreatmentDynasylan ® HMDSDynasylan ® VTEODynasylan ® HMDSDynasylan ® VTEO* low adsorption capacity** low sulfur content*** water scavenger19

Commercial ContactEurope, Central-, Southamerica, AfricaEvonik Degussa GmbHWeissfrauenstr. 960287 Frankfurt am MainGermanyPhone +49 69/218-53 17Fax +49 69/218-35 41e-mail siliconerubber@evonik.comwww.aerosil.comNAFTAEvonik Degussa Corporation379 Interpace Parkway, P.O. Box 677Parsippany, NJ 07054-0677USAPhone +1 973/541-8510Fax +1 973/541-8501AsiaNIPPON AEROSIL CO., LTD.Sales & Marketing DivisionP.O. Box 7015Shinjuku Monolith 13F3-1, Nishi-Shinjuku 2-chomeShinjuku-ku, Tokyo163-0913 JapanPhone +81 3/33 42-17 14Fax +81 3/33 42-17 61Technical ServiceEurope, Central-, Southamerica, AfricaEvonik Degussa GmbHInorganic MaterialsRodenbacher Chaussee 4P.O. Box 134563403 Hanau-WolfgangGermanyPhone +49 61 81/59-65 59Fax +49-61 81/59-42 01NAFTAEvonik Degussa CorporationAkron Technical Center3500 Embassy Parkway,Suite 100 & 125Akron, OH 44333USAPhone +1 800/833-5222Phone +1 330/668-2235Fax +1 330/668-3846Asia (without Japan)Evonik Degussa China Co. Ltd.Chundong Road,Xinzhuang Industry Park 55201108 ShanghaiChinaPhone +86 21/6119 1070Fax +86 21/6119 1075JapanNIPPON AEROSIL CO., LTD.Applied Technology Service3 Mita-choYokkaichi, Mie510-0841 JapanPhone +81 593/45-5270Fax +81 593/46-4657Or your local Evonik contactThis information and all further technicaladvice is based on our present knowledgeand experience. However, it implies noliability or other legal responsibility on ourpart, including with regard to existingthird party intellectual property rights,especially patent rights. In particular, nowarranty, whether express or implied, orguarantee of product properties in thelegal sense is intended or implied. Wereserve the right to make any changesaccording to technological progress orfurther developments.The customer is not released from theobligation to conduct careful inspectionand testing of incoming goods.Performance of the product describedherein should be verified by testing,which should be carried out only byqualified experts in the sole responsibilityof a customer. Reference to trade namesused by other companies is neither arecommendation, nor does it imply thatsimilar products could not be used.www.aerosil.comIM-28-1-1DEZ08MO