Characteristic

• Approval: German Federal Aviation Authority
• Applications: Production of gliders, motor gliders and motor planes. Boat and shipbuilding. Sports equipment, model airplanes, moulds and tools.
• Operational Temperature:
  • -60°C -> +50-60°C (-75°F->+120-140°F) without heat treatment
  • -60°C -> +80-100°C (-75°F->+175-210°F) with heat treatment
• Processing: At temperatures between 10°C and 50°C (50-120°F) All usual processing methods.
• Special Properties: Extremely good physiological compatibility. Good mechanical and thermal Properties. Pot life from 45 minutes to approximately 5 hours.

Application

Laminating resin system approved by the German Federal Aviation Authority with different pot lives for processing of glass, carbon and aramid fibers featuring high static and dynamic load ability.

After heat treatment at 50-55°C (120-130°F), the system meets the standards for gliders and motor gliders (operational temperatures -60°C (-75°F) to +54°C (+130°F). In order to meet the standards for motor planes with operational temperatures -60°C (-75°F) to +72°C (+160°F), heat treatment at 80°C (+175°F) is necessary.

The range of pot lives is between approximately 45 minutes and 5 hours. The hardeners have the same mixing ratio and can be mixed together in any ratio. This permits a selection of the optimum system for all processing methods. After initial curing at room temperature, the components manufactured are workable and de-moldable. You will receive high-gloss and non-tacky surfaces, even with unfavorable pre-curing conditions, e.g. lower temperatures or high humidity.

The mixing viscosity guarantees fast and complete impregnation of the reinforcement fibers; however, the resin will not spill out of the fabrics on vertical surfaces. In order to obtain special properties, it is also possible to add fillers to the mixture of resin/hardener, such as Aerosil, micro balloons, cotton flocks, metal powder, etc.

If high heat resistance or aircraft approval are not necessary, hardener 285 can also be used without heat treatment afterwards. However, the indicated properties will only be obtained after heat treatment at temperatures over 50°C (120°F).

The laminating resin system has a hydrophilic character (higher humidity absorption, lower resistance to diffusion of steam). Therefore we do not expect any problems concerning compatibility in case of combination with polyester gel coats, diverse paints (e.g. on the basis of PUR), etc. However, comprehensive tests are indispensable.

Since the approval of laminating resin L285 in 1985, nearly all manufacturers of planes and gliders and – especially because of the extremely good physiological compatibility have used it – it is the most commonly used system in the aircraft industry today. It often happens that workers who have experienced problems with some epoxy resins concerning allergies or skin irritation are able to process laminating resin L285.

The relevant industrial safety regulations for handling epoxy resins and hardeners and our instructions for safe processing are to be observed.

Specifications

• L285 Resin Density: 1.18 – 1.23 g/cm³/25°C (9.85 – 10.26 lbs/gal/77°F)
• L285 Resin Viscosity: 600 – 900 mPas/25°C (cps/77°F)
• L285 Epoxide Equivalent: 165-170
• L285 Epoxide Value: 0.59 – 0.65
• L285 Color: max 3 Gardner
  
  
• 285 Hardener Density: 0.94 – 0.97 g/cm³/25°C (7.84 – 8.10 lbs/gal/77°F)
• 285 Hardener Viscosity: 50 – 100 mPas/25°C (cps/77°F)
• 285 Hardener Amine Value: 480 – 550 mg/KoH/g
• 285 Hardener Color: max 3 Gardner for transparent hardener however it is colored transparent blue
  
  
• 287 Hardener Density: 0.93 – 0.96 g/cm³/25°C (7.76 – 8.00 lbs/gal/77°F)
• 287 Hardener Viscosity: 80 – 100 mPas/25°C (cps/77°F)
• 287 Hardener Amine Value: 450 – 500 mg/KoH/g
• 287 Hardener Color: max 3 Gardner for transparent hardener however it is colored transparent blue
  

Processing Details

• L285 Resin Average EP – Value: 0.62
• 285 Hardener Average Amine Equivalent: 64
• 287 Hardener Average Amine Equivalent: 64

Mixing Ratio L285 Resin: Hardener

• Parts by weight: 100:40 (+/-2)
• Parts by volume: 100:50 (+/-2)

Temperature Rise While Curing

H285 Hardener				H287 Hardener
Time in minutes:	60	90		60	90	120	180	240	300	360
Temperature C:	50	100		24	26	28	35	46	58	64
Temperature F:	120	210		75	78	82	95	113	139	146

Gel Time

Modulus Of Rigidity DIN 53445

Gel Time

Modulus of Rigidity DIN 53445

Glass Transition Temperature (TG)

Rise Of Glass Transition (TG)

Mechanical Data Of Un-reinforced Resin

Typical data according to WL 5.3203 Parts 1 and 2 of the German Aviation Materials Manual:

• Curing: 24 h at 23°C (75°F) + 15 h at 60°C (140°F)
• Density: 1.18-1.20 g/cm³ (9.8-10 lbs/gal)
• Flexural Strength: 110-120 N/mm² (16-18 psi x 10³)
• Modulus of Elasticity: 3.0-3.3 kN/mm² (4.6-4.8 psi x 10⁵)
• Tensile Strength: 70-80 N/mm² (10-11.5 psi x 10³)
• Compressive Strength: 120-140 N/mm² (18-20 psi x 10³)
• Elongation: 5-6.5%
• Impact Strength: 45-55 Nmm/mm² (220-300 lbs/inch)
• Shore Hardness: 80-85 D
• Water Absorption (%):
  • 24 h 23°C (75°F) 0.20-0.30%
  • 7 d 23°C (75°F) 0.60-0.80%
• Fatigue Strength under Reversed Bending Stresses acc. to DLR Brunsw:
  • 10% >2 x 10⁴
  • 90% >2 x 10⁶