BMI-689M Low Viscosity Liquid Bismaleimide

Main features

Hydrophobic
High adhesion to various substrates
Superior thermal stability

Product Description

BMI-689M is a lower cost alternative to our standard BMI-689. It is made with the same ingredients but with a streamlined (less expensive and more tuned to high volume capable) process. BMI-689M is darker in color and higher in viscosity but still much lower in viscosity when compare to the other liquid BMI resins.

Note: both the BMI-689 and BMI-689M use a partially hydrogenated backbone material (maybe >75% hydrogenated). It was made specifically this way vs. using fully hydrogenated raw materials to both avoid patent concerns while making it less expensive. There are no patent concerns presently with the BMI-689M formula. Though one would imagine that it is desirable to use fully hydrogenated raw materials to avoid any reactions with the left over double bonds that are possible with the partially hydrogenated material, in the many years experience we have with both the BMI-689 and BMI-689M, this concern appears to be unwarranted.

BMI-689M is a unique low viscosity liquid bismaleimide based on a non-hydrogenated dimer diamine backbone. It can be homo-cured via UV or free radical initiators to form tough, hydrophobic, cross-linked polyimides. The material has excellent low pH hydrolytic resistance and thermal stability. The amorphous nature of this BMI allows it to be used in a variety of applications including mixed cure systems (e.g. epoxy and BMI), mixed BMI systems or where a low viscosity, free radical cured resin is required. It is soluble in most aromatic and aliphatic solvents such as toluene, xylene, NMP, etc.

BMI-689M is recommended for use as an additive or base resin in adhesives that are designed for high temperature resistance. It has excellent adhesion to a variety of substrates. When used as a base resin, it can produce films that are tough, flexible and demonstrate good peel strength. BMI-689M is darker in color compared to BMI689 and higher in viscosity but still much lower in viscosity when compare to the other liquid BMI resins.

BMI-689M cures free radically so it is subject to oxygen inhibition to some degree. Thermal curing with an abundance of catalyst will usually overcome the problem. Bmi resins do demonstrate self photoinitialization when exposed to UV but polymerization is more complete and requires much less energy when a UV photoinitiator is used in the formula. We would not suggest using UV without an initiator for our BMI resins. Our favorite initiator is Irgacure IR-819. It works well in broad band and i-line systems.

BMI-689M has a Tg value of around 42ºC by DMA. When measuring using a TMA the values are lower by 20 - 30ºC so you would be looking in the 10 - 25ºC range for a pure BMI formulation. Very low. This is why we suggest using acrylates to boost the Tg of formulations if your hydrophobicity concerns allow for their use.

Packaging

Please select Package Type before adding your product to your cart.

TDS, SDS & Technical Documents

R1442 - BMI-689M - BMI
English (Technical Data Sheet (TDS))
BMI-689M SDS
English (Safety Data Sheet (SDS))

Technical Specifications

General Properties

Appearance

Dark Amber

Functionality

Molecular weight

689 g/mol

Thermal Properties

Decomposition Temperature

>400 °C

Weight Loss @ 300°C

1.5 %

Other Properties

Storage Temperature

5 °C

Physical Properties

Viscosity

5000 ±2000 mPa.s

About Krayden

About Krayden

About Krayden

BMI-689M Low Viscosity Liquid Bismaleimide

Main features

Product Description

BMI-689M

Technical Specifications

Recently viewed products

Leading Brands Trust in Our Products and Services