ARALDITE® 2020 A/B

• Low viscosity, water white adhesive
• Especially suitable for glass and ceramic bonding
• Suitable for clear castings and laminates
• Refractive index similar to that of glass

Pretreatment

The strength and durability of a bonded joint are dependant on proper pretreatment of the surfaces to be bonded. At the very least, joint surfaces should be cleaned with a good degreasing agent such as acetone, iso-propanol (for plastics) or other proprietary degreasing agents in order to remove all traces of oil, grease and dirt.Low grade alcohol, gasoline (petrol) or paint thinners should never be used. The strongest and most durable joints are obtained by either mechanically abrading or chemically etching (“pickling”) the degreased surfaces. Abrading should be followed by a second degreasing treatment.

Application of adhesive

The resin/hardener mix is applied with a spatula to the pretreated and dry joint surfaces.A layer of adhesive 0.05 to 0.10 mm thick will normally impart the greatest lap shear strength to a joint.The joint components should be assembled and clamped as soon as the adhesive has been applied. An even contact pressure throughout the joint area will ensure optimum cure.
Equipment maintenance

All tools should be cleaned with hot water and soap before adhesives residues have had time to cure. The removal of cured residues is a difficult and time-consuming operation. If solvents such as acetone are used for cleaning, operatives should take the appropriate precautions and, in addition,avoid skin and eye contact.

Typical times to minimum shear strength

LSS = Lap shear strength.
Note - There is a risk of exotherm when casting the product in bulk or in thick sections (>1cm) when the mould is insulating. This should be assessed before proceeding.

Unless otherwise stated, the figures given below were all determined by testing standard specimens made by lap jointing 170 x 25 x 1.5 mm strips of aluminium alloy. The joint area was 12.5 x 25 mm in each case.The figures were determined with typical production batches using standard testing methods. Average lap shear strengths of typical metal-to-metal joints (ISO 4587) (typical average values) Cured for 16 hours at 40oC and tested at 23°C,Pretreatment - Sand blasting.

*Compression lap shear strength.

Average lap shear strengths of typical plastic-to-plastic joints (ISO 4587) (typical average values)
Cured for 16 hours at 40°C and tested at 23°C
Pretreatment - Lightly abrade and iso-propanol degrease.

Lap shear strength versus temperature (ISO 4587) (typical average values)
Cure: (a) = 7 days /23°C; (b) = 24 hours/23°C + 30 minutes/80°C

Roller peel test (ISO 4578) (typical average values) Cured 16 hours/40°C - 0.2 N/mm

Flexural Properties (ISO 178) Cure 16 hours/ 40oC tested at 23oC (typical average values)

Flexural Strength - 75 MPa
Flexural Modulus - 2400 MPa
Glass transition temperature (typical average values) 40°C

Lap shear strength versus immersion in various media (typical average values) Unless otherwise stated, L.S.S. was determined after immersion for 90 days at 23°C

Lap shear strength versus tropical weathering
(40/92, DIN 50015; typical average values)
Cure: 16 hours/40°C; Test: at 23°C

Lap shear strength versus heat ageing
Cure:16 hours/40°C

  Thermal cycling
  100 cycles of 6 hour duration from -30°C to 70°C 4.5N/mm²

Araldite® 2020/A and Araldite® 2020/B may be stored at room temperature provided the components are stored in sealed containers. The expiry date is indicated on the label.Our products are generally quite harmless to handle provided that certain precautions normally taken when handling chemicals are observed. The uncured materials must not, for instance, be allowed to come into contact with food- stuffs or food utensils, and measures should be taken to prevent the uncured materials from coming in contact with the skin, since people with particularly sensitive skin may be affected. The wearing of impervious rubber or plastic gloves will normally be necessary; likewise the use of eye protection. The skin should be thoroughly cleansed at the end of each working period by washing with soap and warm water. The use of solvents is to be avoided. Disposable paper - not cloth towels - should be used to dry the skin. Adequate ventilation of the working area is recommended.