Fine ChemicalsDyhard®Make the best links with Dyhard productsTable of ContentsEpoxy Resins Manufacture of DicyandiamideThe Dicyandiamide-Epoxy Reaction Mixing and Fine Grinding CenterDyhard®Epoxy Resin Hardeners Dyhard®Accelerators Printed Circuit Boards Composite Materials Structural AdhesivesPowder Coatings Supplier DirectoryEnvironment,Safety,Health and QualityReferencesContact2p.3p.5p.6p.7p.8p.9p.11p.12p.13p.14p.16p.17p.18p.19Epoxy ResinsSince epoxy resins were introduced to the market in the1950s,they have found a large variety of applications inadhesives,casting compounds,composite materials,electrical laminates and coatings [1,2,3].Epoxy resins possess high chemical and thermal stabili-ty,coupled with excellent mechanical and electrical pro-perties.The vast majority of commercially used epoxyresins are derived from glycidyl ethers of bisphenol A.Depending on the degree of polymerization,liquid (n = 0–0.5),semisolid (n = 1) or solid (n = 3–12) epoxyresins are formed.In applications where intrinsic flame resistance is required,semisolid resins based on tetrabromobisphenol A are used.Epoxy resins are characterized by their epoxy equivalentweight (EEW).This is the weight of a resin quantity con-taining exactly 1 mole of epoxy groups.In the reaction with a hardener,the meltable epoxyresin is converted to a crosslinked thermoset solid.Themost important industrial hardeners contain active NHgroups,which form 2-hydroxy amine units with epoxygroups in an addition reaction.3Epoxy ResinsThe stoichiometric mixing ratio of an epoxy resin with an amine hardener iscalculated as follows:parts of curing agent H-equivalent weight (HEW) of the hardener x 100=per 100 parts epoxy resin (phr) epoxy-equivalent weight (EEW) of the resin Aliphatic or aromatic amines react with epoxy resins atroom temperature,so the processing time is limited.Anearly unlimited shelf life,combined with fast curing atelevated temperatures,are achievable with so-calledlatent epoxy resin hardeners.Dicyandiamide,a product of Degussa AG,is the mostwidely used epoxy resin hardener for curing at elevatedtemperature.Its applications extend from electricallaminates to composite materials,from structural adhe-sives to powder coatings.Schematic figure of a polymer network formed by the reaction of an epoxy resinwith a tetrafunctional amine4Manufacture of Dicyandiamide5The Dicyandiamide-Epoxy ReactionAt moderate temperatures,dicyandiamide does not re-act with epoxy resins.This is because of the low basicityand poor solubility in epoxy resins.Dicyandiamide assuchreacts very quickly with epoxy resinsstarting atabout 180 °C.The reaction is accelerated autocatalyticallyby basic intermediates of the hardener reaction.The reaction mechanism consists oftwo stages:a) Addition of the NH groups to the epoxy ringb) Condensation of OH groups with CN multiple bondsto form heterocyclic systems.2-Iminooxazolidines (1)and tertiary amines (2) can be considered the main pro-ducts in the hardened resin [4].(1)(2)In contrast to other amine hardeners,the original di-cyandiamide molecule degrades into small functionalunits [5].Because of the complicated reaction mecha-nism,the curing reaction does not follow an exact stoi-chiometry.Depending on hardening conditions,onedicyandiamide molecule reacts with 6–7 epoxy groups.This reaction results in an empirical H-equivalent weightof 12–14 for dicyandiamide.The particle size of the dicyandiamide is essential to theachievable properties of the cured resin.Dicyandiamidewith large grain size frequently forms inclusions,whichcan cause the workpiece to fail.Ultramicronized dicyan-diamide has the following advantages:Higher reactivity,no unreacted inclusions with unreact-ed particles,no mechanical failure,no surface defects oncoatings.6Mixing and Fine Grinding CenterIn combination with our dicyandiamide production,high-tech grinding with air jet mills is combined at theTrostberg/Schalchen site in a unique mixing and finegrinding center.Small grain sizes (down to 6 µm) and narrow grain dis-tribution,as a rule,result in high reactivities of the har-deners and accelerators.Besides the standard products,this center can also beused for toll production.Grain sizes,microscopic photographsair jet millimage:Hosokawa Alpine7Dyhard®Epoxy Resin HardenersMicronized Dicyandiamide:Dyhard®100Dyhard®100 SDyhard®100 SF98% < 40 µm98% < 10 µm98% < 6 µmaffords the widest range of applications as an epoxy resin hardener.Degussa’s high-tech grinding provides for narrow grain size distribution.Low-turbidity Dicyandiamidefor solutions:Dyhard®T03Dyhard®G03special quality for prepregs and electrical laminates with high purity and excellent dissolution properties.Dyhard®solutions:Dyhard®L10for prepregs and electrical laminates,feature low turbidity and reduced effort for resin users.Dyhard®pastes:Dyhard®D 50 EPDyhard®DF 50 EPPastes of micronized dicyandiamide simplify handling and improve dispersibility in liquid epoxy resins as a master batch for composites and adhesives.Substituted Dicyandiamide:Dyhard®OTBYields e.g.high-gloss powder coatings with very good mechanical properties.Matt curing agent:Dyhard®PIN +Dyhard®CA ABDyhard®PIN and Dyhard®CA AB at a mixing ratio of 45% Dyhard®PIN with 55% Dyhard® CA AB results in powder coatings e.g.with low-gloss,high gloss stability and low yellowing.8Dyhard®AcceleratorsWhy accelerators?Dicyandiamide,subject to the formulation,offers excel-lent mechanical and electrical properties and a straight-forward processing of the finished resin formulation.The necessary curing temperatures,however,are toohigh for many applications.A Dyhard®accelerator redu-ces the curing temperature and maintains the goodproperties of the cured resin.Dyhard®UR typesBlocked accelerators with a high latency,which entailfast curing after the impact of heat.Dyhard®imidazoles:Unblocked accelerators that achieve high curing rateseven at low temperatures.They are highly soluble in theepoxy resin but have reduced shelf lives.Comparison of the reactivities of epoxy/dicyandiamide formulations(1) Without accelerator(2) With blocked accelerator (Dyhard®UR types)(3) With unblocked accelerator (Dyhard®imidazole)Dyhard®UR TypesDyhard®UR 200Dyhard®UR 300Dyhard®UR 5009Dyhard®AcceleratorsIn combination with dicyandiamide,Dyhard®UR typesprovide for good shelf lives of one-component systems.Above 130 °C,short curing rates are achieved.Dyhard®UR 500 accelerator is the most reactive UR type.In addition,good TG values are achieved.Dyhard®UR types decompose under the influence ofheat to form isocyanates and catalytically active dime-thylamine [6,7,8].Following activation by heating abovethe onset temperature,the accelerators lose their latencyto form free dimethylamine.The isocyanates released react with epoxies to formadditional linkages via oxazolidinones (3).The applications for Dyhard®UR types are prepregsfor composites and structural adhesives.(3)Dyhard®ImidazolesDyhard®MI:Dyhard®PI:Dyhard®MIA:2-Methylimidazole epoxy resin adductBecause of their unrivaled catalytic properties,imida-zoles play a unique role in natural enzymes that catalyzenucleophilic reactions.The action of Dyhard®imidazoleson the dicyandiamide-epoxy reaction is based on thesame mechanisms [9].They afford high reactivities at only 100 °C and providean appreciable accelerator action with the addition ofonly 0.1 phr.The main applications for Dyhard®imidazoles areelectrical laminates,adhesives and powder coatings.10Printed Circuit BoardsFormulation Example for an ImpregnatingSolution125.0 parts Epikote 1141-B-80 (Resolution)30.0 parts Dyhard®L 10 10.0 parts methyl glycol0.1 part Dyhard®Ml-C (or Dyhard®Pl)A glass fabric (USType 7628,200 g/m2,finish Z 6040 by DowCorning) is impregnated with this solution,then dried and pre-reacted in a hot-air oven.Preferably 8 layers of the prepregmade by this method are compressed in a tiered press at 175 °Cto make a FR-4 printed circuit board.The following printed circuit types are based on the same resincomposition:NEMA FR-3,FR-4,CEM-1,CEM-3,DIN ISO EP-CP01,EP-GC02.Typical requirements to an FR-4 laminate:Glass transition temperature Water absorption after 24 hr in water at 23 °CSolder bath resistance at 260 °CSurface resistanceDielectric constant at 1 MHz 135 °C< 0.25%> 20 sec1010ohms5.4Dyhard®for printed circuit boards:Dyhard®T03/G03Dyhard®L10Dyhard®MI-C,PIhardenerhardeneraccelerator11Composite MaterialsComposites are materials greatly demanded in the aeronautics,athletic and automobile industries as replacements for aluminum or wood.An attractive new application is wind vanes for wind power plants.Formulation Example 1 (Sporting Goods)100 parts D.E.R.331 (Dow) 7 parts Dyhard®100 S 3 parts Dyhard®UR 300Glass or carbon fiber fabric can be impregnated withthis.After pre-reaction in a hot-air oven,the prepregcures at 140 °C.Formulation Example 2 (High-Tech Composites)60 20 9 18.5 4.5 parts Araldite MY 720 (Vantico) parts Epikote 1001 (Resolution)parts Epikote 828 (Resolution)parts Dyhard®D 50 EPparts Dyhard®UR 500Unidirectional carbon fiber filaments are impregnatedwith the preheated resin composition.After compres-sion,the laminates have the following properties:Resin content:Tensile strength:Tensile modulus:Interlaminar shear strength:Compressive strength:Modulus of compression:36%1700 MPa130 GPa100 MPa1100 MPa125 GPaDyhard®for Composites:Dyhard®100 - 100 SFDyhard®pastesDyhard®UR typesDyhard®imidazolesDyhard®MIA 5HardenerHardener,premixed in liquid resinBlocked acceleratorUnblocked acceleratorAccelerator12Structural Adhesivesimage:Daimler-ChryslerA mixture of epoxy resin,hardener,accelerator and fil-lers is prepared.This mixture is stable in storage if blockedaccelerators are used.Curing begins on heating in therange of 100–180 °C.Such hot-melt or package adhe-sives are used,for example,in the automobile industryor in all other uses that require rapid hardening andstorage stability.Adhesive bonding is better than welding.1-Component Adhesive for Structural Adhesive Bonding72.5 parts3.4 parts0.2 part4.8 parts19.1 partsRütapox VE 3356 (Bakelite)Dyhard®100 S Dyhard®UR 200 Aerosil R 202 (Degussa)Wollastonit (Kemolit) S1 (Osthoff-Petrasch)Impact-Modified 1-Component Adhesive60 parts 30 parts 13 parts 2 parts 10 parts 4 parts D.E.R.331 (Dow) D.E.R.431 (Dow) Dyhard®D 50 EP Dyhard®UR 500 Struktol Polydis 3614 (Schill & Seilacher)Aerosil R 805 (Degussa)Stable for one year of storage at room temperature,hardens at 180 °C.Stable in storage for one year,hardens at 150 °C.Dyhard®for Adhesives:Dyhard®100 - 100 SFDyhard®pastesDyhard®UR typesDyhard®imidazolesHardenerHardener,premixed in liquid resinBlocked acceleratorUnblocked accelerator13Powder CoatingsPowder coatings consist of solid resin,pigments,fillers,hardeners and accelerators.These substances are mixed,melted in an extruder,and then ground.The powder issprayed electrostatically,typically on metal surfaces,andhardened at temperatures as low as approximately 160 °C.Powder coatings are environmentally friendly (no orga-nic solvents and less waste) and are increasingly prefer-red over conventional coatings.Formulation Example for High-Gloss Coatings60 parts36 parts 1.6 parts 0.4 part 0.1 part 0.1 part Araldite GT 7203 (Vantico) Titanium dioxide 2160 (Kronos Titan)Dyhard®100 SDyhard®Ml Perenol F 40 (Henkel)BenzoinFormulation Example for Matt Hybrid Coatings100 parts 67.3 parts 2.7 parts 3.3 parts 60.6 parts 29.5 parts D.E.R 662 E (Dow) Albester 2660 (Eastman)Dyhard®PINDyhard®CA ABTitanium dioxide 2160 (Kronos Titan)Durcal 5 (Omya)This mixture obtains a high-gloss coating that providesexcellent protection against mechanical and chemicalinfluences.Micronized dicyandiamide also featuresexcellent corrosion protection and optimum surface(ultrafine particles) and is also approved for food contactunder FDA,BGA and EU guidelines.is extruded at 110 °C (at 200 rpm).Typical properties of this mixture:At baking temperature:Gloss:Cupping index IE:Mandrel bending test:10´,180 °C18%6 mm8 mm10´,200 °C20%6 mm10 mmThe use of Dyhard®PIN/Dyhard®CA AB at a 45/55% ratio produces high gloss-stability and low yellowing at different baking temperatures,starting at 170 °C,even in darkly pigmented formulations.14Image:Werndl Büromöbel AGHbmG kinhcetthciL OGILO:egamiFormulation Example for High-Gloss Clear Coatings100 parts D.E.R 663 E (Dow)8 parts Araldite GT 3032 (Vantico)6 parts Dyhard®OTB is extruded at 95 °C (180 rpm).Typical properties of this mixture are:At baking temperature:15´,160 °C10´,180 °CGloss (60 °C):110%110%Cupping index IE:10 mm10 mmMandrel bending test:< 3 mm< 3 mmBall impact:> 160 lb/in> 160 lb/inIn a high-gloss epoxy system Dyhard OTB gives verygood flow properties with best corrosion resistance atlow curing temperatures.Dyhard®for Powder Coating:Dyhard®100 - 100 SFHardenerDyhard®PIN + CAABMatt curing agentDyhard®OTBHardenerDyhard®imidazolesAccelerator Dyhard®MIA 5AcceleratorDyhard®UR 300AcceleratorPowder Coatings15SupplierFlexibilization additivesThixotropizing agentsSupplier DirectoryReactive thinnersPolyester resinsWetting agentsEpoxy resinsGlass fabricsPigmentsBakelite GmbH,D-58609 IserlohnCabot Corp.,Tuscola,IL 6193,USAVantico AG,CH-4002 BaselDegussa AG,D-40474 DüsseldorfDOW Chemical Europe S.A.,CH-8810 HorgenGevetex Textilglas-GmbH,D-5120 HerzogenrathHenkel KGaA,D-4000 Düsseldorf 1Kronos Titan-GmbH,D-51307 Leverkusen 1Eastman Chemical Company,Kingsport,TN 37662,USAOmya AG,CH-4665 OftringenOsterhoff-Petrasch KG,D-22848 NorderstedtSchill & Seilacher,D-22113 HamburgResolution Nederland BV,3190 AN Hoogvliet RTSolventsTrademarks are the property of the respective trademark holders.Comparative Data for Epoxy ResinsLiquid ResinsEEW [g/mol]Viscosity at 25 °C [Pas]Softening Point [°C]Dicyandiamid dose [phr]18812––7Solid Resins750solid1001.7Brominated Epoxy Resins4701(solution)3.0Bakelite RütapoxVantico AralditeDow D.E.R.Resolution Nederland BV0164601031182870046633003Fillers8011511112016Environmental Safety,Health and QualityAt Degussa AG,the quality of products and services,theprotection of the environment,our health,plant andoccupational safety are equal goals.An integrated ma-nagement system used to achieve these goals is recog-nized outside the company and confirmed through certification programs.Regular internal audits identifyand evaluate potentials for improvement .The dedica-tion,creativity and innovative expertise of our employ-ees is the key to the success of this system.Quality assurance procedures for raw materials,processmonitoring and product control provide a quality stan-dard that meets our customers’high standards.Thishigh standard is reinforced by independent modernanalytical support.There is no contradiction between Ecology and Economy.According to our self commitment,we are constantlyimproving our production processes to reduce anypotential environmental impact of our operations andto preserve resources.Occupational safety is a key criterion for Degussa.Wecarefully analyse potential safety risks in order to mini-mise them.Learning from faults and avoiding them,isthe most important task.ISO 9001:2000ISO 14001,BS 8800RESPONSIBLE CARE17References18[1] H.Lee,K.Neville,Handbook of Epoxy Resins,McGraw Hill Book Co.,NY 1967[2] C.A.May,Epoxy Resins,M.Dekker,NY 1988[3]B.Ellis,Chemistry and Technology of Epoxy Resins;Blackie A & P,Glasgow 1993[4] M.D.Gilbert,N.S.Schneider,Mechanism of the Dicyandiamide/ Epoxid Reaction,Macromolecules 1991 (24),360-369[5] S.A.Zahir,The Mechanism of the Cure of Epoxide Resins by Cyanamide and Dicyandiamide,Adv.Org.Coat.Sci.Technol.Ser.1982 (4),83-102[6] J.Barwich,D.Guse,H.Brockmann,Härtung vonEpoxidharzen mit Dicyandiamid und Monuron,Adhäsion 1989 (5),27-30[7] T.Güthner,B.Hammer,Curing of Epoxy Resins with Dicyandiamide and Urone,J.Appl.Polym.Sci.1993 (50),1453 - 1459[8] N.Poisson,A.Maazouz,H.Sautereau,M.Taha,X.Gambert,Curing of Dicyandiamide Epoxy Resins Accelerated with Substituted Ureas,J.Appl.Polym.Sci.1998 (69),2487 - 2497[9] F.Ricciardi,W.A.Romanchick,M.M.Joullie,Mechanism of Imidazole Catalysis in the Curing of Epoxy Resins,J.Polym.Sei.Polym.Chem.Ed.1983 (21),1475-1490Visit us on the Internet at www.dyhard.com or throughthe Degussa Fine Chemicals home page www.finechemicals.de Or call us:Service Center Western Europe:Toll-free:+800-31303130 Dr.Volker GrunwaldPhone:+41-1-2743-102Fax:+41-1-2743-103E-mail:volker.grunwald@degussa.comMarketing:Barbara HuberPhone:+49(0)8621-86-2935Fax:+49(0)8621-86-3598E-mail:barbara.huber@degussa.comTechnical Service:Dr.Sylvia HuberPhone:+49 (0) 8621-86-2476Fax:+49 (0) 8621-86-2172E-mail:sylvia.huber@degussa.comData sheets,prices,technical information,samples,andmore are available upon request.This information is furnished without warranty,repre-sentation,inducement or license of any kind,except thatit is accurate to the best of Degussa AG’s and DegussaCorporation’s knowledge or obtained from sourcesbelieved by Degussa to be accurate.Degussa AG andDegussa Corporation do not assume any legal responsi-bility for use or reliance upon same.Tests should be car-ried out only by chemists or chemically qualified labtechnicians.Before using any chemical,read its labeland Material Safety Data Sheet.ContactThis information is based on certain types of formulati-ons.Therefore it is not binding.Some of the formulati-ons shown have been carried out in individual andsingle applications only.These formulations,however,are therefore without obligation.EH-Provided that a new edition is published this brochure30.3loses ist validity.0-005.1-BMarch 2003G-2-CF19GermanyDegussa AGFine ChemicalsFI-FC-AG-KDDr.-Albert-Frank-Str.32D-83308 TrostbergPhone:+49-8621-86-2935Fax:+49-8621-86-3598www.finechemicals.de