Bonding Apparatus and Method

An apparatus for bonding substrates, the apparatus comprising:

• a frame;
• an anvil roll rotatably connected with the frame and adapted to rotate about a first axis of rotation, the anvil roll comprising an outer circumferential surface;
• a bonding roll rotatably connected with the frame and adapted to rotate about a second axis of rotation, wherein the first axis of rotation is parallel with the second axis of rotation, the bonding roll comprising:
• a first bearer ring comprising a first bearer surface extending from a first end to a second end to define a circumferential length, the first bearer ring extending for less than 360 degrees around the second axis of rotation;
• a second bearer ring comprising a second bearer surface extending from a first end to a second end to define a circumferential length, the second bearer ring extending for less than 360 degrees around the second axis of rotation;
• the second end of the first bearer surface circumferentially offset from the first end of the second bearer surface to define a circumferential gap region between the first end and the second end;
• a pattern element comprising a pattern surface circumferentially offset from the first and second bearer rings and positioned in the circumferential gap region;
• wherein the bonding roll and the anvil roll are biased toward each other with a force F, such that as the anvil roll and bonding roll rotate, a pattern pressure Pp is created between the pattern surface and the outer circumferential surface of the anvil roll and bearer pressures Pb are created between the first and second bearer surfaces and the outer circumferential surface of the anvil roll;
• and
• wherein the force F displaces the pattern surface by a distance Xp;
• wherein the force F displaces the first bearer surface and the second bearer surface by a distance Xb;
• and
• wherein Xb is about equal to Xp.

A method of bonding substrates, the method comprising the steps of:

• providing an anvil roll adapted to rotate about a first axis of rotation, the anvil roll comprising an outer circumferential surface;
• providing a bonding roll adapted to rotate about a second axis of rotation adjacent the anvil roll, wherein the first axis of rotation is parallel with the second axis of rotation, the bonding roll comprising a bearer surface and a pattern surface;
• rotating the anvil roll and the bonding roll in opposite directions such that the pattern surface and the bearer surface alternatingly contact the outer circumferential surface of the anvil roll;
• biasing the anvil roll and the bonding roll toward each other with a force, F;
• displacing the pattern surface by a distance Xp with the force F;
• displacing the bearer surface by a distance Xb with the force F, wherein Xb is about equal to Xp;
• and
• advancing a first substrate and a second substrate in a machine direction between the bonding roll and the anvil roll to form a discrete bond region between the first and second substrates.