DEHESIVE® PSA 850 R can be used for coating of several film-substrates such as Polyester, Polyamide, Polyimide and others substrates for manufacture of different silicone pressure sensitive adhesive tapes and other articles.
Processing
DEHESIVE® PSA 850 R can be diluted with aliphatic or aromatic solvent (e.g. toluene, white spirit, naphtha). It is typically blended with addition curing silicone PSA system (e.g. DEHESIVE® PSA 765). For an optimum balance of surface tack, adhesion strength and cohesive strength it is necessary to cure the coated DEHESIVE® PSA 850 R for 1 – 2 min. at 140 – 150°C by using additing DEHESIVE® 765 and catalyst C05 or PT 5. It is recommended to remove the solvent before curing process at 80 – 90 °C for ~0.5 min. Higher temperature can cause incorporation of the solvent into the adhesive film, which can impair the adhesive properties.
For tape applications DEHESIVE® PSA 850 R can be formulated with a peroxide-crosslinker e.g. Bis-(2,4-dichlorobenzoyl peroxide, which is added in a concentration of 0.5 –3.0 wt.%. With higher peroxide levels the crosslinking
density and cohesion strength can be increased, while
adhesion strength is lowered.
For an optimum balance of surface tack, adhesion
strength and cohesive strength it is necessary to cure
the coated DEHESIVE® PSA 850 R for 2 – 5 min. at
140 – 150°C by using Bis-(2,4-dichlorobenzoylperoxide
and at 170 – 200°C in case of Dibenzoylperoxide
is used. It is recommended to remove the
solvent before curing process at 80 – 90 °C for 2 – 4
min. Higher temperature can cause premature
decomposition of the peroxide-crosslinker and
incorporation of the solvent into the adhesive-film,
which can impair the adhesive properties.
