Bonding Apparatus and Method

Abstract

The present disclosure relates to methods and apparatuses for mechanically bonding substrates together. The apparatuses may include a pattern roll having three or more pattern elements protruding radially outward, wherein each pattern element includes a pattern surface. The pattern surfaces are also separated from each other by gaps having minimum widths. The pattern roll may be adjacent an anvil roll to define a nip between the pattern surfaces and the anvil roll, wherein the pattern roll is biased toward the anvil roll to define a nip pressure between pattern surfaces and the anvil roll. As substrates advance between the pattern roll and anvil roll, the substrates are compressed between the anvil roll and the pattern surfaces to form a discrete bond region between the substrates. During the bonding process, some of yielded substrate material also flows from under the pattern surfaces and into the gaps to form gap grommet regions.

What is claimed is: 
     
         1 . A method of bonding substrates, the method comprising the steps of:
 rotating an anvil roll;   rotating a pattern roll adjacent the anvil roll, the pattern roll including a base circumferential surface, a first pattern element including a first pattern surface, a second pattern element including a second pattern surface, and a third pattern element including a third pattern surface; wherein each pattern surface defines an area, A, wherein A is greater than about 0.25 mm 2  and less than about 2.00 mm 2 ; wherein each pattern element protrudes outward from the base circumferential surface to define a distance, Hp, between the first, second, and third pattern surfaces and the base surface, and wherein each pattern element is bounded by a perimeter; wherein the first and second pattern surfaces are separated by a first gap having a minimum width, D 1 , wherein the first and third pattern surfaces are separated by a second gap having a minimum width, D 2 , and wherein the second and third pattern surfaces are separated by a third gap having a minimum width, D 3 , and wherein D 1 , D 2 , and D 3  are greater than 0.20 mm and less than about 3.00 mm;   biasing the bonding roll toward the anvil roll to define a nip pressure of greater than about 40,000 PSI and less than about 60,000 PSI between each pattern surface and the anvil roll;   advancing a first substrate and a second substrate in a machine direction between the pattern roll and the anvil roll; and   compressing the first substrate and the second substrate between the anvil roll and the first, second, and third pattern surfaces to form a discrete bond region between the first and second substrates.   
     
     
         2 . The method of  claim 1 , wherein the step of compressing further comprises moving a first portion of material of the first and second substrates from between the first pattern surface and the anvil to the first gap and the second gap. 
     
     
         3 . The method of  claim 2 , wherein the step of compressing further comprises moving a second portion of material of the first and second substrates from between the second pattern surface and the anvil to the first gap and the third gap. 
     
     
         4 . The method of  claim 3 , wherein the step of compressing further comprises moving a third portion of material of the first and second substrates from between the third pattern surface and the anvil to the second gap and the third gap. 
     
     
         5 . The method of  claim 1 , wherein each pattern surface defines substantially the same area, A. 
     
     
         6 . The method of  claim 5 , wherein the area, A, is about 0.70 mm 2 . 
     
     
         7 . The method of  claim 1 , wherein at least one of D 1 , D 2 , and D 3  is about 0.30 mm. 
     
     
         8 . The method of  claim 1 , wherein D 1 , D 2 , and D 3  are substantially the same.