EPOXY COMPOSITES. Technical Service dpt., Resins JIŘÍ MAŠEK, JAN HYRŠL. 1

Transkript

1 EPOXY COMPOSITES Technical Service dpt., Resins JIŘÍ MAŠEK, JAN HYRŠL 1

2 COMPOSITES = ment a material, COMPOSED from at least 2 components Many different composite material exists: natural (granite,...), biological (wood, bone,...) anorganic (concrete,...),... polymer... fibre-reinforced composites (FRC) 2

3 FIBRE-REINFORCED COMPOSITES FRC constitutes of the fibre reinforcement embedded in the resinous matrix. they are strong and light => ideal construction material for diversity of applications. Properties of composite are resulted as a superposition of its components properties. The static mechanical properties (strength...) will be determined largely by the reinforcement. Dynamic-mechanical properties (toughness, brittleness...) will determine considerably the resin used as matrix. Epoxy resin E-type Glass fibre Epoxyglass composite E- modulus [GPa] 3 72,4 45 Tensile strength [GPa] 0,1 2,4 1,1 3

4 FIBRE REINFORCEMENT Different sorts of fibres are used: E-modulus Tensile Application [GPa] strength [GPa] E-glass ( electrical ) standard S-glass ( stronger ) high-strength ECR-Glass (corrosion resistant) corrosive environment Silica/Quartz high temp. Basalt high temp. Carbon fibre (high strength) high-strength, ultra-light Carbon fibre (graphite type) ultra-light, low elongation Aramide fibre hi-tec Different forms of fibres are used: rowings woven fabrics (st. pre-formed) chopped strand mat tapes staple (chopped fibre) 4

5 Strength versus density for various engineering materials 5

6 Strength versus maximum service temperature for various engineering materials 6

7 Thermal conductivity versus thermal expansion for various engineering materials 7

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10 MATRIX RESIN Different sorts of resins are used: Polyester Vinyl Ester Epoxy Phenolic Bismaleimide Polyimide Cyanate ester Nylon Polycarbonate Polyacetal Polyether imide (PEI) Polyetheretherketone (PEEK) Polyphenylene sulphide (PPS) Polyamide imide (PAI)... Epoxides provide some advantages, like: high temperature resistance ( polyester resins), very low mould shrinkage ( polyester or vinyl ester), low volatility while curing (in comparison of content of volatile styrene in polyester and vinyl ester resins), good environmental and solvent resistance (but lower UV resistence), very good adhesion to most reinforcement materials (vs. necessity of use of silane coupling agent for glass and inadequate bonding to carbon or aramide at polyester resins), good impact strength ( polyester, polyimide), low absorbtion of water ( polyester or polyimide resins), good workability and acceptable economy ( polyimide or polybenzoxazole). 10

11 MATRIX RESIN Epoxides have some limitations, too: Limited pot life when resin and hardener are mixed (but sufficient for common processing) Cured systems have poor resistance to U.V. Thus, outdoor exposure over time tends to yellow and chalk coat (gel coats are used to prevent it) Limited temperature resistance: Ambient cured systems ~ C, heat cured up to 180 C (but better then many other resins) Resins and hardeners need to be handled with care in sensitive individuals to prevent dermatitis or rash (but more health & environ friendly then many other.. ) Epoxides provide some advantages, like: high temperature resistance ( polyester resins), very low mould shrinkage ( polyester or vinyl ester), low volatility while curing (in comparison of content of volatile styrene in polyester and vinyl ester resins), good environmental and solvent resistance (but lower UV resistence), very good adhesion to most reinforcement materials (vs. necessity of use of silane coupling agent for glass and inadequate bonding to carbon or aramide at polyester resins), good impact strength ( polyester, polyimide), low absorbtion of water ( polyester or polyimide resins), good workability and acceptable economy ( polyimide or polybenzoxazole). 11

12 PRODUCTION & APPLICATION Most frequented processing techniques: Prepreging Hand Lay-Up RTM / RI Filament Winding Pultrusion Typical fields of application: Aerospace Automotive Construction industry Mechanical engineering Mould construction, tooling Sport and leisure Transportation Wind energy 12

13 PREPREGING Prepreg is a term for pre-impregnated glass or carbon fibre, mat or fabric type reinforcement soaked by mixture of epoxy resin, latent hardener, fillers and additives. The system is only partially cured to the non-sticky, semi-solid state (so called B-Stage material) which allows easy handling and further processing, mainly bonding of other components. B-Stage prepreg should be stored in cool place since complete polymerization is most commonly done by heat. Spliting of curing cycle (prepreg composite) influences beneficaly on final properties of casting (mechanical & thermal fastness). It lowers exothermic peak and thus shrinkage. It allows also more precisious distribution of fibres in casted part, thus higher fibre content in the appropriate spots of composite, resulting higher strength and thinwalled parts. 13

14 PREPREGING MELT PREPREG PROCESS 1 Unwind of fabric/rowings 2 Impregnating bath with resin 3 Squeezing out rollers 4 Oven, pre-curing to tacky B-stage 5 Upper separating film 6 Carrier (back-up) paper/foil 7 Prepreg wind-up 14

15 PREPREGING 7 4 3,2 1 SOLVENT PREPREG MACHINERY 1 Unwind of fabric/rowings 2 Impregnating bath with resin solution 3 Squeezing out rollers 4 Oven, solvent evaporating an precuring to non-tacky B-stage 7 Prepreg wind-up 15

16 PREPREGING The Prepreg is only semi-finished product, which requires next processing to finish the curing and reach final shape, often in an oven or autoclave: EVACUATION PROCESS prepreg is placed under evacuated foil for good shape and deareation and then put into curing oven (so-called Vacuum Bagging, VB). AUTOCLAVE PROCESS prepreg is placed under evacuated foil for good shape and deareation and then put into autoclave under pressure 1-10 bar (Autoclave Assisted Vacuum Bagging, AVB). This procedure provides better quality of surface. MOULDING PROCESS prepreg plies are applied into mould and cured in the oven or directly cured by heated mould. COMBINED PRESSURE PROCESS - prepreg is pressed to the mould by inflated inner rubber bag (e.g. Bladder Infusion Process BLIP) WINDING PROCESS prepreg tape is winded on the spindle shape (e.g. production of fishing rods). 16

17 PREPREGING PRODUCTS: Precise parts with top mechanical ant thermal properties Printed circuit boards (PCB, brominated - FR4) Aerospace parts Automotive construction parts (leaf springs) Engine hoods & pans Electro insulating panels, laminates and mica insulators Car bodies Boxes, cases Fishing rods

18 PREPREGING RESIN SYSTEM PROPERTIES: low to medium viscosity, optimal rheology properties excelent thermal and mechanical strength excellent toughness and cracks resistance sufficiently long pot-life able to interrupt curing in B-stage pre-curing 10 min at 100 C, aftercuring by C for min. PORTFOLIO SELECTION RESINS: CHS-EPOXY 200 M 75, CHS-EPOXY B 200 M 80, CHS-EPOXY B 201 M 80, CHS-EPOXY 301, CHS-EPOXY 411 HARDENERS: DICY SPECIAL SYSTEMS: CHS-EPODUR

19 HAND LAY-UP Hand lay-up (manual laminating) is a labour-intensive but lowinvestment process suitable for production of very large and complex parts as well as for production in small series. A pigmented layer (gel coat) is sprayed on the mould to obtain a good surface which protects the laminate structure. The actual laminate is built up on this gel coat. A fabric is typically used for reinforcement. Epoxy resin is applied and impregnated by using a brush or with felt, PTFE or metal laminating rollers. The product is generally cured without application of pressure and at ambient temperature. Subsequent heat treatment is required to enhance the properties. 19

20 HAND LAY-UP HAND LAY UP PROCESS 1 Mould tool 2 Gel coat (optional) 3 Reinforcement fabric 4 Resin system 5 Consolidation roller 20

21 HAND LAY-UP A number of Hand Lay-Up variants was developed, e.g. : VACCUUM FOIL PROCESS a hand layed mold is placed under evacuated foil for good shape and deareation (so-called Vacuum Bagging, VB). SPRAY LAY UP PROCESS instead of placing reinforcement and impregnating the soaked mat the composite layer is made by spraying of mixture resin with fibre staple. A special spraying gun with additional fibre chopping device is used. 21

22 HAND LAY-UP PRODUCTS: Big parts produced in small series or by pieces Boats Aerospace parts Hoods, wall panels, housings & pans Car bodies Wind blades Boxes, cases

23 HAND LAY-UP RESIN SYSTEM PROPERTIES: medium viscosity, optimal rheology properties low emission, smell, toxicity sufficiently long pot-life excellent toughness and cracks resistance at low temperature high electrical strength, surface and volume resistivity. Curing 24 hours/rt at first step and C at second step for 2 48 hours. EPOXY PORTFOLIO SELECTION RESINS: CHS-EPOXY 498, CHS-EPOXY 501, CHS-EPOXY 520, CHS-EPOXY 531, CHS-EPOXY 582, CHS-EPOXY 619 HARDENERS: TELALIT 0420, TELALIT 0500, TELALIT 0590, TELALIT 0600, TELALIT 0492 SPECIAL SYSTEMS: CHS-EPODUR , CHS-EPODUR , CHS-EPODUR

24 INJECTION MOULDING In Injection moulding process reinforcement material is placed in half of the mould and the second half of the mould clamped over the top. The reinforcement material can be pre-pressed into the mould shape; this is known as "preform". For resin injection, resin materials are machine-mixed prior to being injected under pressure (~ 5 Bar) into the mould cavity. To ensure complete wetting of the reinforcement material either a pinch off device is used or a vacuum can be applied to draw the resin through the cavity. Once the mould cavity is filled, the resin inlet is closed and the laminate allowed to cure. In order to release the component from the mould high temperature release agents are necessary due to the highly exothermic nature of the cure. 24

25 INJECTION MOULDING RTM PROCESS 1 Mould tool (bottom) 2 Dry reinforcement preform 3 Mould tool (top) 4 Coupling of mould parts 5 Inlet - resin injected under pressure 6 Outlet vaccum assistence (optional) 25

26 INJECTION MOULDING A number of variants was developed, e.g. : RESIN-TRANSFER MOLDING (RTM) resin is transferred under pressure into an enclosed mould into which the fibre reinforcement has been placed; additional vacuum can be applied for better quality and few voids. Curing is accomplished normally without external heat. in BLADDER INFUSION PROCESS BLIP, an deflating or/and inflating foil bladder inside the mould is used for (additional) resin transfer, VACUUM ASSISTED RTM VARTM, the combination of RTM and VI, widely applied technique for big-sized, high quality composite parts, RESIN INFUSION UNDER FLEXIBLE TOOLING RIFT (RFI), a variant of vacuumdriven RTM in which one of the solid tool faces is replaced by a flexible polymeric film, SEEMAN COMPOSITE RESIN INFUSION MOULDING PROCESS - SCRIMP, a type of RIFT process developed for manufacturing of boat hulls incl. core, VACUUM BAGGING VB, a type of RIFT process in which a soft foil bag is used as the upper mould face. 26

27 INJECTION MOULDING SCRIMP PROCESS 27

28 INJECTION MOULDING RESIN INFUSION PROCESS 28

29 INJECTION MOULDING A number of variants was developed, e.g. : RESIN INFUSION (RI) A molding process in which vacuum is used to fibres with resin. Works with closed or semi-closed molds. VACUUM ASSISTED RESIN INJECTION VARI, have moulds that are usually vented, only a partial vacuum holds the mould in place and provides the moulding force and also aids the reduction of voids in laminates of large area. VACUUM INFUSION VI (VIMP), is an extension of VARI where a complete vacuum is applied. This technique can be used either for high quality (low voidage) aerospace parts, or high volume production parts with flexible tooling. 29

30 INJECTION MOULDING PRODUCTS: Precisious small to big parts produced with high reproducibility in medium-numbered series. Enables big variety in wall thickness (from 0.01 mm) Mechanical parts Automotive (cabins for trucks, spoilers, body), Transportation (railway carriage, tramcars), Wind mill blades, Airplane structural elements, Boats etc

31 INJECTION MOULDING RESIN SYSTEM PROPERTIES: low viscosity ( mpa.s) sufficiently long pot-life excellent toughness and cracks resistance at low temperature optimal rheology properties high electrical strength, surface and volume resistivity. Curing C at first step and C at second step for 2 16 hours. PORTFOLIO SELECTION RESINS: CHS-EPOXY 498, CHS-EPOXY 501, CHS-EPOXY 531, CHS-EPOXY 582, CHS-EPOXY 619 HARDENERS: TELALIT 0420, TELALIT 0500, TELALIT 0590, TELALIT 0600 SPECIAL SYSTEMS: CHS-EPODUR , CHS-EPODUR , CHS-EPODUR , CHS-EPODUR , CHS-EPODUR

32 FILAMMENT WINDING Filament winding process is used specially for production of hollow bodies of fibre-reinforced composites. Filaments (glass, carbon or aramid) are impregnated in a bath of epoxy resin and hardener and applied to a rotating hub in a specified pattern. This is accomplished by rotating the mandrel while a delivery head precisely places fibres on the mandrel surface. By winding continuous strands in very precise patterns, structures can be built with properties stronger than steel at much lighter weights. This process produces a high laminate quality with a high degree of automation, high precision in fibre content and economy of production. 32

33 FILAMMENT WINDING 33

34 FILAMMENT WINDING FILAMMENT WINDING MACHINERY 34

35 FILAMENT WINDING PRODUCTS: Hollow cylindrical, conical, or spherical in shape items with inner high quality surface Dimmensions Ø 2 cm 5 m 2 5 m length Pipes for the utilities and oil & gas industries Gas cylinders / flasks Pressure brake cylinders Tanks Rollers Insulation tubes etc

36 PULTRUSION Pultrusion process is used specially for production of continuous composite angle bars and shaped pipes with defined cross-section. Continuous fibre is pulled through a resin bath or has resin injected on to it. The wetted fibre is then pulled through a heated (~ 150 C) die (or shaping hub, preformer), which is in the shape of the component. In addition to shaping the fibre the die also acts to control the amount of resin and initiate curing. On exiting the die, the material is automatically cut to the required length. 36

37 PULTRUSION PULTRUSION MACHINERY 37

38 PULTRUSION PRODUCTS: Continuous composite angle bars, rods, strips, sharped pipes of different cross-section Cross-section dimmensions 3 mm.. >40 cm Beams, girders Gratings Bridges Ladders Frameworks etc

39 PULTRUSION RESIN SYSTEM PROPERTIES: low viscosity ( mpa.s), optimal rheology at working temperature sufficient pot-life excellent toughness and cracks resistance low shrinking Typical curing C/ 1-10 minutes, post-curing possible PORTFOLIO SELECTION STANDARD RESINS: CHS-EPOXY 501, CHS-EPOXY HARDENERS: TELALIT 0590 SPECIAL SYSTEMS: CHS-EPODUR , CHS-EPODUR , CHS-EPODUR , CHS-EPODUR

40 FRC MARKET GLASS Fiber Reinforced Plastic (GFRP) Composites Market is worth $45.12 bn by While the transportation, aerospace & defense segments occupy topmost positions in the GFRP Composites market with 49% share by value in 2013, maximum growth is expected from wind energy and aerospace & defense in the near future. China and India are the fastest growing markets. The world market for CARBON Fibre Reinforced Plastics (CFRP) composites reached $26.84 bn in The potential of next growth is in the automotive industry, in the development of the wind power market, offshore drilling and deeper oil and gas digging. [acc.: MarketsandMarkets] 40

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42 TECHNICAL SERVICE RESINS 2015 DÍKY ZA POZORNOST THANK YOU FOR YOUR ATTENTION! 42