Bonding is a strength to attach the lasted shoe upper to the outsole unit, currently oscar are doing conventional type cementing construction and new technology direct injection. The shoe upper are usually made of leather,
suede or synthetic leather while the outsole are made of nitrile rubber or molded PVC or thermoplastic polyurethane.
To enhance a good bonding between the two components the lasted upper must be buffed on the lasting edges to help
to break the smooth surface for better adhesion. The outsole unit must be cleaned by a cleaning agent called ‘primer’.
This is to clear away excess oil or mold release agent which is crucial for a good bonding strength.
Cementing range (multipurpose series and angel series)
For conventional type of footwear construction, water massed solvent base cement are carefully applied to upper
and outsole unit and later pass through a heat tunnel to activate the cement. Fixing the upper to the outsole required good
skill workmanship so that the upper are sitting on the best position of the outsole. Finally the completed shoe are then
press together firmly by a hydraulic presser.
Direct Injection Technology
In the new age of technology, direct injection method is being used for sole bonding process. The midsole will have a molded
cavity for injection. Polyurethane will be injected to the cavity. This is a technical way to add cushioning and also make the
midsole as a stabilizer to the bottom of a shoe.
Injection range (supertec series, supertec premium series and titan series)
The beauty of direct injection polyurethane is acting as a melted adhesive to bond the leather upper to the outsole unit. PU is the
polymer of Daltoped and Suprasec. There are many grade of PU in the market. It is absolutely depending on the compound and
Therefore choosing a pairs of good safety shoe must start from it bonding condition.