Adhesive compositions

Abstract

Polydiorganosiloxane polyoxamide, linear, block copolymers and methods of making the copolymers are provided. The method of making the copolymers involves reacting a diamine with a polydiorganosiloxane precursor having oxalylamino groups. The polydiorganosiloxane polyoxamide block copolymers are of the (AB) n type.

1 . An adhesive composition comprising:
 a) a polydiorganosiloxane polyoxamide comprising at least two repeat units of Formula I:   
       
         
           
           
               
               
           
         
         wherein
 each R 1  is independently an alkyl, haloalkyl, aralkyl, alkenyl, aryl, or aryl substituted with an alkyl, alkoxy, or halo, wherein at least 50 percent of the R 1  groups are methyl; 
 each Y is independently an alkylene, aralkylene, or a combination thereof, 
 G is a divalent residue equal to a diamine of formula R 3 HN-G-NHR 3  minus the two —NHR 3  groups; 
 R 3  is hydrogen or alkyl or R 3  taken together with G and with the nitrogen to which they are both attached forms a heterocyclic group; 
 n is independently an integer of 40 to 1500; and 
 p is an integer of 1 to 10; and 
 an asterisk (*) indicates a site of attachment of the repeat unit to another group in the copolymer; 
 
         b) a tackifier; and 
         c) an adhesion promoter. 
       
     
     
         2 . An article comprising:
 a substrate; and   an adhesive layer adjacent to at least one surface of the substrate, the adhesive layer comprising   
       a) a polydiorganosiloxane polyoxamide comprising at least two repeat units of Formula I: 
       
         
           
           
               
               
           
         
       
       wherein
 each R 1  is independently an alkyl, haloalkyl, aralkyl, alkenyl, aryl, or aryl substituted with an alkyl, alkoxy, or halo, wherein at least 50 percent of the R 1  groups are methyl; 
 each Y is independently an alkylene, aralkylene, or a combination thereof; 
 G is a divalent residue equal to a diamine of formula R 3 HN-G-NHR 3  minus the two —NHR 3  groups; 
 R 3  is hydrogen or alkyl or R 3  taken together with G and with the nitrogen to which they are both attached forms a heterocyclic group; 
 n is independently an integer of 40 to 1500; and 
 p is an integer of 1 to 10; and 
 an asterisk (*) indicates a site of attachment of the repeat unit to another group in the copolymer; and 
 
       b) a tackifier,
 wherein the adhesive layer is crosslinked. 
 
     
     
         3 . An article comprising:
 a substrate; and   an adhesive layer adjacent to at least one surface of the substrate, the adhesive layer comprising   
       a) a polydiorganosiloxane polyoxamide comprising at least two repeat units of Formula I: 
       
         
           
           
               
               
           
         
       
       wherein
 each R 1  is independently an alkyl, haloalkyl, aralkyl, alkenyl, aryl, or aryl substituted with an alkyl, alkoxy, or halo, wherein at least 50 percent of the R 1  groups are methyl; 
 each Y is independently an alkylene, aralkylene, or a combination thereof; 
 G is a divalent residue equal to a diamine of formula R 3 HN-G-NHR 3  minus the two —NHR 3  groups; 
 R 3  is hydrogen or alkyl or R 3  taken together with G and with the nitrogen to which they are both attached forms a heterocyclic group; 
 n is independently an integer of 40 to 1500; and 
 p is an integer of 1 to 10; and 
 an asterisk (*) indicates a site of attachment of the repeat unit to another group in the copolymer; and 
 
       b) a tackifier,
 wherein the adhesive layer is cured. 
 
     
     
         4 . A method of preparing an adhesive article, the method comprising:
 providing an adhesive composition comprising   
       a) a polydiorganosiloxane polyoxamide comprising at least two repeat units of Formula I: 
       
         
           
           
               
               
           
         
       
       wherein
 each R 1  is independently an alkyl, haloalkyl, aralkyl, alkenyl, aryl, or aryl substituted with an alkyl, alkoxy, or halo, wherein at least 50 percent of the R 1  groups are methyl; 
 each Y is independently an alkylene, aralkylene, or a combination thereof; 
 G is a divalent residue equal to a diamine of formula H 2 N-G-NH 2  minus the two —NH 2  groups; 
 R 3  is hydrogen or alkyl or R 3  taken together with G and with the nitrogen to which they are both attached forms a heterocyclic group; 
 n is independently an integer of 40 to 1500; and 
 p is an integer of 1 to 10; and 
 an asterisk (*) indicates a site of attachment of the repeat unit to another group in the copolymer; and 
 
       b) a tackifier;
 applying the adhesive composition to a surface of a substrate; and 
 crosslinking the adhesive composition. 
 
     
     
         5 . A method of preparing an adhesive article, the method comprising:
 providing an adhesive composition comprising   
       a) a polydiorganosiloxane polyoxamide comprising at least two repeat units of Formula I: 
       
         
           
           
               
               
           
         
       
       wherein
 each R 1  is independently an alkyl, haloalkyl, aralkyl, alkenyl, aryl, or aryl substituted with an alkyl, alkoxy, or halo, wherein at least 50 percent of the R 1  groups are methyl; 
 each Y is independently an alkylene, aralkylene, or a combination thereof; 
 G is a divalent residue equal to a diamine of formula H 2 N-G-NH 2  minus the two —NH 2  groups; 
 R 3  is hydrogen or alkyl or R 3  taken together with G and with the nitrogen to which they are both attached forms a heterocyclic group; 
 n is independently an integer of 40 to 1500; and 
 p is an integer of 1 to 10; and 
 an asterisk (*) indicates a site of attachment of the repeat unit to another group in the copolymer; and 
 
       b) a tackifier;
 applying to adhesive composition to a surface of a substrate; and 
 curing the adhesive composition.