Bismaleimide film

Bismaleimide film adhesive


Bismaleimide film presentation

One-component bismaleimide adhesive film  


• Temperature resistant to 240 °C
• Very high bond strength at high temperatures
• Very resistant to various chemicals
• Good bonds to aluminium, PTFE (Teflon®), and glass
• Improved easy and clean processing


Description

 
307 is a solvent-free, hot-curing adhesive film with high temperature and media resistance. At room temperature it
is not tacky and can be easily cut to the shape of the bond area. Tackiness is developed at ca. 120 °C, just before
curing. This adhesive is used for bonding piezo ceramics in ultrasonic wave sensors onto metal surfaces where
very low  mechanical  damping  is  required  over  a  broad  temperature  range.  It is  also  used  for  high  temperature
resistant structural bonding of PTFE layers onto aluminium with long-term temperature resistance up to 240 °C.


Processing


Surface  Pretreatment :  307  should  be  prefereably  used  on  carefully  degreased  and  pretreated  surfaces.  Better
joints are obtained on mechanically abraded and degreased surfaces, while chemical etching leads to best results.
It is recommended to follow specific directions for surface pretreatments of various materials.
Application  of  Adhesive  :  The  adhesive  film  can  be  cut  to  the  shape  of  the  bond  area  either  manually  or
automatically. The transparent support film must be removed and the yellow adhesive film placed on one substrate.
The second substrate should be placed on the adhesive film and fixed by mechanical clamps (or similar tools) for
curing. Alternatively, the substrates can be heated to 120 °C. Upon contact with the hot surface, the adhesive film
becomes tacky and sticks to the surface. The second hot substrate should then be placed on the adhesive and
fixed for curing.
Curing : The adhesive film requires a minimum curing temperature of 150 °C. Post curing at 200 °C improves its
properties significantly – especially its temperature and chemicals resistance. Only low fixing pressure is needed
during the curing. The curing duration depends on how fast the adhesive can reach the needed temperature in the
bond line. This is mostly governed by the thermal conductivity and the geometry of the substrates. As a guideline,
curing  should  last  for  at  least  30  min  after  reaching  150  °C  and  200  °C,  respectively.  For  first  tests  a  curing
schedule  of  2h  at  150  °C  +  2h  at  200  °C  is  recommended.  Suitable  tests  under  real-life  conditions  should  be
conducted by the user.


Chemical resistance

We tested the stability of adhesive joints in strong acids (sulphuric acid, phosphoric acid, at pH 1) and elevated
temperatures up to 60 °C with good results. From experiments at customers we also know that solvent resistance
is  very  high  (acetone,  methyl  ethyl  ketone,  and  N-methyl  pyrrolidone  were  tested).  We  do  not  have  much
information about resistance in basic media (pH 10). Fuel resistance was tested in biodiesel and regular diesel with
excellent results as well. However, it is important to note that the surface preparation of the bonded parts has a
strong  influence  on  the  resistance  of  the  overall  adhesive joint. Water  and  other  aqueous  media  are  especially
known  to  penetrate  into  the  bondline  and  destroy  the  adhesion,  even  if  the  adhesive  layer  itself  is  still  intact.
Surface treatment with adhesion promoters (silanes) can often help in such cases.


Storage

307 may be stored in its original container between 4 and 35 °C (do not freeze!). Avoid direct sunlight.
Shelf life is 12 months. Expiry date is indicated on the label.


Disposal

Spare amounts of the adhesive should be cured and then disposed of according to local regulations.


Handling Precautions

When using the adhesive wear protective glasses and gloves. Refer to further instructions in the MSDS.


Final Advanced Materials provides also a full rang of epoxy adhesives