Multilayer polymer sheets

Abstract

Multilayer polymer sheets are provided, as well as related methods, systems, and appliances.

1 . (canceled) 
     
     
         2 . A method of making a multilayer dental aligner for repositioning a patient's teeth from a first arrangement toward a second arrangement, the method comprising:
 providing a multilayer sheet comprising:
 a first layer; 
 a second layer; and 
 a third layer; and 
 wherein the first layer comprises a first polymer having:
 a flexural modulus greater than 150,000 psi; 
 an elongation at break of greater than 70%; and 
 
 wherein the second layer comprises a second polymer different than the first polymer, the second polymer having:
 an elongation at break of greater than 200%; 
 
   providing a mold;   thermoforming the multilayer sheet over the mold to form a plurality of tooth-receiving cavities configured to receive and reposition the patient's teeth from the first arrangement toward the second arrangement; and   trimming excess material from the thermoformed multilayer sheet to form the dental aligner.   
     
     
         3 . The method of  claim 2 , wherein the first polymer comprises a co-polyester, and wherein the second polymer comprises a thermoplastic polyurethane elastomer. 
     
     
         4 . The method of  claim 3 , wherein the first polymer has a tensile strength yield of 4000 psi to 6500 psi. 
     
     
         5 . The method of  claim 3 , wherein the first polymer has an elongation at yield of greater than 4%. 
     
     
         6 . The method of  claim 3 , wherein the first polymer has a tensile modulus of greater than 150,000 psi. 
     
     
         7 . The method of  claim 3 , wherein the first polymer has a light transmission of between 400 nm and 800 nm of greater than 75%. 
     
     
         8 . The method of  claim 3 , wherein the first polymer has a light transmission between 400 nm and 800 nm of greater than about 75%. 
     
     
         9 . The method of  claim 3 , wherein the second polymer has a hardness from 60A to 85D. 
     
     
         10 . The method of  claim 3 , wherein the second polymer has an ultimate tensile strength of greater than 5000 psi. 
     
     
         11 . The method of  claim 2 , wherein the first layer comprises a first polymer having an elastic modulus greater than the second polymer of the second layer. 
     
     
         12 . The method of  claim 2 , wherein the first polymer comprises a co-polyester; wherein the second polymer comprises a thermoplastic polyurethane elastomer; and wherein the third layer comprises a third polymer comprising a co-polyester. 
     
     
         13 . The method of  claim 2 , wherein the first polymer comprises a co-polyester; wherein the second polymer comprises a thermoplastic polyurethane elastomer; and wherein the third layer comprises a third polymer comprising a thermoplastic polyurethane. 
     
     
         14 . The method of  claim 13 , wherein the first layer is disposed between the second layer and the third layer. 
     
     
         15 . The method of  claim 2 , wherein the first layer is disposed between the second layer and the third layer. 
     
     
         16 . A method of making a multilayer dental aligner for repositioning a patient's teeth from a first arrangement toward a second arrangement, the method comprising:
 providing a multilayer sheet comprising:
 a first layer; 
 a second layer; and 
 a third layer; and 
 wherein the first layer comprises a co-polyester and wherein the second layer comprises a thermoplastic polyurethane elastomer; 
   providing a mold;   thermoforming the multilayer sheet over the mold to form a plurality of tooth-receiving cavities configured to receive and reposition the patient's teeth from the first arrangement towards the second arrangement; and   trimming excess material from the thermoformed multilayer sheet to form the dental aligner.   
     
     
         17 . The method of  claim 16 , wherein the third layer comprises a co-polyester. 
     
     
         18 . The method of  claim 16 , wherein the third layer is disposed adjacent to the first layer. 
     
     
         19 . The method of  claim 18 , wherein the third layer is co-extruded with or laminated to the first layer. 
     
     
         20 . The method of  claim 16 , wherein the multilayer sheet further comprises a fourth layer comprising a thermoplastic polyurethane elastomer. 
     
     
         21 . The method of  claim 20 , wherein the first layer and the third layer are disposed between the second layer and the fourth layer. 
     
     
         22 . The method of  claim 20 , wherein the third layer comprises a thermoplastic polyurethane elastomer. 
     
     
         23 . The method of  claim 22 , wherein the first layer is disposed between the second layer and the third layer. 
     
     
         24 . The method of  claim 16 , wherein the co-polyester of the first layer has a flexural modulus greater than 150,000 psi. 
     
     
         25 . The method of  claim 16 , wherein the co-polyester of the first layer has an elongation at break of greater than 70%. 
     
     
         26 . The method of  claim 16 , wherein the co-polyester of the first layer has an elongation at yield of greater than 4%. 
     
     
         27 . The method of  claim 16 , wherein the co-polyester of the first layer has a tensile strength yield of 4000 psi to 6500 psi. 
     
     
         28 . The method of  claim 16 , wherein the co-polyester of the first layer has having a tensile modulus of greater than 150,000 psi. 
     
     
         29 . The method of  claim 16 , wherein the co-polyester of the first layer has a light transmission between 400 nm and 800 nm of greater than about 75%. 
     
     
         30 . The method of  claim 16 , wherein the thermoplastic polyurethane elastomer of the second layer has a compression set of greater than 40% after 24 hours at 70° C. 
     
     
         31 . The method of  claim 16 , wherein the thermoplastic polyurethane elastomer of the second layer has an elongation at break of greater than 200%. 
     
     
         32 . The method of  claim 16 , wherein the thermoplastic polyurethane elastomer of the second layer has a hardness from 60A to 85D. 
     
     
         33 . The method of  claim 16 , wherein the co-polyester has an elastic modulus greater than the thermoplastic polyurethane elastomer.