LTM26 series prepregs are low to medium viscosity epoxy resin matrices formulated to cure at low initial cure temperatures.

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1 Cytec 1 of 6 LTM 26 series LTM 26 series LTM26 series prepregs are low to medium viscosity epoxy resin matrices formulated to cure at low initial cure temperatures. These prepregs can be used to manufacture components by autoclave, press or vacuum bag moulding techniques. After post cure, these resins are suitable for service temperatures up to 115 C (239 F) or 90 C (194 F). Features Out life between 2 and 5 days at (0 F) 12 months storage life at 18 C (0 F) Low initial cure temperatures between and 60 C (140 F) Service temperatures up to 115 C (239 F) (LTM26EL) Excellent mechanical properties, equivalent to many 120 C (248 F) curing prepreg systems Adhesion to foam core materials High quality components can be made from low cost and low temperature moulds Rapid cure capability between 80 C (176 F) and 120 C (248 F) Product variants LTM26: Low viscosity epoxy prepreg which forms the base resin for all LTM26 series variants LTM26B: Black pigmented version of LTM26 LTM26EL: Extended life version of LTM26 LTM26ELB: Black pigmented version of LTM26EL LTM26ELFR: Fire retarded version of LTM26EL, passing JAR vertical burn LTM26ELFRB: Black pigmented version of LTM26ELFR LTM26ELFS: Low smoke (DIN5510, M1 compliant) variant of this resin system, see PDS1035 Related documents De bulking guidelines (TDS1036) Oven vacuum bag processing lay up and bagging guidelines (TDS1041) Autoclave processing lay up and bagging guidelines (TDS1037) Related products LTX26B expanding epoxy syntactic film (PDS1136) LTA26 and LTA26NC resin films

2 Cytec 2 of 6 LTM 26 series Cure cycle Oven vacuum bag cure Vacuum bag pressure Recommended cure cycle LTM26 series Recommended cure cycle LTM26EL series Minimum of 980mbar (29 Hg)* 1 to 3 C (1.8 to 5.4 F)/minute Maximum of 3 C (5.4 F)/minute to room temperature *This is the ideal vacuum level, however, it is recognised that it is not always possible to attain. If in doubt, please contact our technical support staff for advice. Autoclave cure Vacuum bag pressure Autoclave pressure Recommended cure cycle LTM26 series Recommended cure cycle LTM26EL series Minimum of 980mbar (29 Hg)* 6.2 bar (90 psi)** 1 to 3 C (1.8 to 5.4 F)/minute Maximum of 3 C (5.4 F)/minute to room temperature *This is the ideal vacuum level, however, it is recognised that it is not always possible to attain. If in doubt, please contact our technical support staff for advice. **If producing sandwich panels, apply the maximum pressure allowable for the honeycomb type. Press cure Mould tools should restrain the flow sufficiently under moulding s to avoid fabric or fibre distortion. Press pressure Recommended cure cycle LTM26 series Recommended cure cycle LTM26EL series Minimum of 2.8 bar (40 psi) A suitable rate (dependant on mould tooling) A suitable rate (dependant on mould tooling) to room temperature Note: Demoulding at the cure temperature may be possible if the tooling is suitably designed. A specific trial is recommended. Alternative cure cycles Temperature LTM26 series Cure time (hours) LTM26EL series minimum optimum minimum optimum C (131 F) C (140 F) C (149 F) C (158 F) C (176 F) C (194 F)

3 Cytec 3 of 6 LTM 26 series Post cure s cured for the recommended period at 60 C (140 F) may be used up to the minimum of 60 C (140 F) in service without additional post cure. In applications demanding maximum temperature or environmental resistance, it is essential that the component is postcured to fully develop the glass transition temperature. Recommended post cure cycle 1 C (1.8 F)/minute* 1 hour at 120 C 0/+5 C (248 F 0/+9 F) Maximum of 3 C (5.4 F)/minute to 60 C (140 F) * For this post cure to be effective the ramp rate of 1 C (1.8 F)/minute must not be exceeded. Alternative stepped post cures are available if your oven temperature controller cannot maintain this heat up rate. Please consult our technical support staff if you require assistance in determining the correct cure cycle for your application. Notes: Large components should be adequately supported to avoid distortion. Other post cure cycles can be used to achieve intermediate levels of cure for lower service temperatures. Physical properties Sample s Results resin density 1 hour at 120 C (248 F) 1.18 g/cm 3 TMA Tg LTM26 LTM26EL + 1 hour at 120 C (248 F) +1 hour at 120 C (248 F) 75 C (167 F) 130 C (266 F) 75 C (167 F) 130 C (266 F) Resin 55 C (131 F) 60 C (140 F) Gel times (minutes) 65 C (149 F) 70 C (158 F) 80 C (176 F) 90 C (194 F) LTM LTM26EL Mechanical properties LTM26/ unidirectional carbon laminates 1 hour at 120 C (248 F) shear 2061 (299) 1764 (256) 142 (21.0) 127 (18.4) 81.0 (11.8) 83.0 (12.0) 1773 (257) 1780 (258) 137 (19.9) 136 (19.7) 82.0 (11.9) 81.0 (11.7) temperature/s 1474 (214) 1582 (229) 118 (17.1) 122 (17.7) 65.0 (9.42) 72.0 (10.4) 1455 (211) 1508 (219) 1241 (180) 132 (19.1) 138 (20.0) 136 (19.7) 68.0 (9.86) (7.68) 48.0 (6.96) Flexural data normalised to 60%Vf Wet 2 hour boil in deionised water.

4 Cytec 4 of 6 LTM 26 series LTM26EL/ unidirectional carbon laminates 1 hour at 120 C (248 F) shear 2052 (298) 1919 (278) 139 (20.0) 129 (18.7) 80.0 (11.6) 81.0 (11.8) 1980 (287) 1916 (278) 130 (18.9) 136 (19.7) 80.0 (11.6) 79.0 (11.5) temperature/s 1764 (256) 1554 (255) 122 (17.7) 120 (17.4) (85.6) 67.0 (9.72) 1530 (222) 1482 (215) 1269 (184) 127 (18.4) 132 (19.1) 141 (20.4) 68.0 (9.86) 51.0 (7.40) 48.0 (6.96) Flexural data normalised to 60%Vf Wet 2 hour boil in deionised water. LTM26/285g/m 2 4x4 twill T300 fibre woven carbon fibre laminates 0.5 hour at 120 C (140 F) shear 1101 (160) 1036 (150) 63.0 (9.14) 58.0 (8.41) 71.0 (10.3) 65.0 (9.43) 963 (140) 955 (138) (9.70) 56.0 (8.12) 61.0 (8.84) temperature/s 1076 (156) 939 (136) 61.0 (8.85) 56.0 (8.12) 852 (124) 779 (113) 631 (91.5) 54.0 (7.83) (8.00) 42.0 (6.10) 37.0 (5.37) Flexural data normalised to 55%Vf Wet 2 hour boil in deionised water.

5 Cytec 5 of 6 LTM 26 series LTM26EL/285g/m 2 4x4 twill T300 woven carbon fibre laminates 0.5 hour at 120 C (140 F) shear 1076 (156) 1043 (151) 60.0 (8.70) 60.0 (8.70) 67.0 (9.72) 62.0 (9.00) 859 (125) 896 (130) (7.69) temperature/s 919 (133) 846 (123) 52.0 (7.54) 54.0 (7.83) 819 (119) 695 (101) 607 (88.0) 50.0 (7.25) 52.0 (7.54) 41.0 (5.95) 35.0 (5.08) Flexural data normalised to 55%Vf Wet 2 hour boil in deionised water LTM26EL/300g/m 2 8 harness satin (epoxy silane) woven glass fibre laminates 0.5 hour at 120 C (140 F) shear 703 (102) 660 (95.7) 22.0 (3.20) 25.0 (3.63) 51.0 (7.40) 52.0 (7.54) 634 (92.0)) 617 (89.5) 23.0 (3.34) 24.0 (3.48) 45.0 (6.53) 50.0 (7.25) temperature/s 656 (95.1) 625 (91.0)) 26.0 (3.77) 21.0 (3.05) 44.0 (6.38) 44.0 (6.38) 547 (79.3) 523 (75.8) 435 (63.1) 22.0 (3.20) 21.0 (3.05) 20.0 (2.90) 41.0 (5.95) 37.0 (5.37) 30.0 (4.35) Flexural data normalised to 55%Vf Wet 2 hour boil in deionised water

6 Cytec 6 of 6 LTM 26 series Availability LTM26 and LTM26EL series prepregs are available in a wide range of reinforcing fabrics and unidirectional tapes, including glass, carbon, aramid and hybrids. Storage Out life* at Storage at 18 C (0 F) LTM26 & LTM26B LTM26EL, LTM26ELB, LTM26ELFR & LTM26ELFRB LTM26 & LTM26B Oven vacuum bag cure Autoclave cure Oven vacuum bag cure Autoclave cure LTM26EL, LTM26ELB, LTM26ELFR & LTM26ELFRB 2 days 3 days** 4 days 5 days** 6 months 12 months *Out life refers to accumulated time out of the freezer before the part is cured. **The out life quoted for autoclave curing is marginally higher than that for oven vacuum bag curing simply because the additional pressure applied to the laminate in an autoclave actually promotes the flow of an aging resin, thus extending resin life. Note: The actual freezer storage life and out life are dependent on a number of factors, including; fibre type, format and application. For certain formats, it may be possible for the storage life and out life to be longer than stated. Please contact our technical support staff for advice. Exotherm LTM26 and LTM26EL prepregs are reactive formulations which can undergo severe exothermic heat up during the initial curing process if incorrect curing procedures are followed. Great care must be taken to ensure that safe heating rates, dwell temperatures and lay up/bagging procedures are adhered to, especially when moulding solid laminates in excess of 3mm (0.12in) thickness. The risk of exotherm increases with lay up thickness and increasing cure temperature. It is strongly recommended that trials, representative of all the relevant circumstances, are carried out by the user to allow a safe cure cycle to be specified. It is also important to recognise that the model or tool material and its thermal mass, combined with the insulating effect of breather/bagging materials can affect the risk of exotherm in particular cases. Please contact our technical department for further information on exotherm behaviour of these systems. Health & safety LTM26 and LTM26EL prepregs contain epoxy resins which can cause allergic reaction on prolonged or repeated skin contact. Avoid contact with the skin. Gloves and protective clothing must be worn. Wash skin thoroughly with soap and water or resin removing cream after handling. Do not use solvents for cleaning the skin. Use mechanical exhaust ventilation when heat curing the resin system. Exhaust from vacuum pumps should be vented to external atmosphere and not into the work place. For further information, consult Cytec Safety Data Sheet numbers: LTM26/LTM26B: SDS 133 LTM26EL/LTM26ELB: SDS 134 LTM26ELFR/LTM26ELFRB: SDS 190 All statements, technical information and recommendations contained in this data sheet are given in good faith and are based on tests believed to be reliable, but their accuracy and completeness are not guaranteed. They do not constitute an offer to any person and shall not be deemed to form the basis of any subsequent contract. All products are sold subject to the Cytec s Standard Terms and s of Sale. Accordingly, the user shall determine the suitability of the products for their intended use prior to purchase and shall assume all risk and liability in connection therewith. It is the responsibility of those wishing to sell items made from or embodying the products to inform the user of the properties of the products and the purposes for which they may be suitable, together with all precautionary measures required in handling those products. The information contained herein is under constant review and liable to be modified from time to time. Copyright 2012 Cytec (Derby) Ltd. All rights reserved worldwide. All trademarks or registered trademarks are the property of their respective owners.