Method of making and using shape memory polymer patches

Abstract

A method of repairing a composite component having a damaged area including: laying a composite patch over the damaged area; activating the shape memory polymer resin to easily and quickly mold said patch to said damaged area; deactivating said shape memory polymer so that said composite patch retains the molded shape; and bonding said composite patch to said damaged part.

1 . A product comprising: a thermo-reversible dry adhesive comprising: a first layer comprising a dry adhesive; a second layer comprising a shape memory polymer; wherein the thermo-reversible dry adhesive has a first shape at a first temperature and a second shape at a second temperature with a load applied. 
   
   
       2 . The product of  claim 1 , wherein the dry adhesive comprises a soft dry adhesive. 
   
   
       3 . The product of  claim 1 , wherein the shape memory polymer comprises a shape memory polymer foam comprising at least one of an epoxy, a polyurethane or a crosslinked vinyl polymer. 
   
   
       4 . A product as set forth in  claim 1  wherein the shape memory polymer comprises: at least one of a rigid epoxy or a flexible epoxy; and at least one of a crosslinking agent or a catalytic curing agent; wherein the rigid epoxy is an aromatic epoxy having at least two epoxide groups, the flexible epoxy is an aliphatic epoxy having at least two epoxide groups, and the crosslinking agent is one of a multi-amine, an organic multi-carboxylic acid, or an anhydride. 
   
   
       5 . A product as set forth in  claim 2 , wherein the soft dry adhesive comprises: at least one of a rigid epoxy or a flexible epoxy; and at least one of a crosslinking agent or a catalytic curing agent; wherein the rigid epoxy is an aromatic epoxy having at least two epoxide groups, the flexible epoxy is an aliphatic epoxy having at least two epoxide groups, and the crosslinking agent is one of a multi-amine, an organic multi-carboxylic acid, or an anhydride. 
   
   
       6 . A product as set forth in  claim 1  further comprising at least one substrate wherein the thermo-reversible dry adhesive is positioned on top of the at least one substrate with the first layer in contact with the at least one substrate. 
   
   
       7 . A product as set forth in  claim 6  wherein the pull-off force of the thermo-reversible dry adhesive with the curved structure is about 0 to 50 N/cm2 for one of the at least one substrate. 
   
   
       8 . A product as set forth in  claim 6  wherein the pull-off force of the thermo-reversible dry adhesive with the relatively flat structure is about 10 to about 200 N/cm2 for one of the at least one substrate. 
   
   
       9 . A product as set forth in  claim 1  wherein the at least one substrate comprises at least one of an automotive body trim piece, a sign, a picture, an automotive side molding, or a surface decorative film. 
   
   
       10 . A product as set forth in  claim 9  wherein the at least one substrate comprises one of stainless steel, glass, aluminum alloy 5657, polypropylene, or Teflon. 
   
   
       11 . A product as set forth in  claim 1 , wherein the dry adhesive is grafted to the shape memory polymer to form a single layer. 
   
   
       12 . A method comprising: providing a thermo-reversible dry adhesive comprising at least one dry adhesive layer and at least one shape memory polymer layer; heating the thermo-reversible dry adhesive to a temperature higher than the glass transition temperature of the shape memory polymer layer; imposing a load on the thermo-reversible dry adhesive while cooling to a temperature below the glass transition temperature of the shape memory polymer layer, so that the dry adhesive layer substantially conforms to a corresponding topography of an underlying substrate to form a strong adhesive bond to the underlying substrate; and releasing the thermo-reversible dry adhesive from the underlying substrate by heating the thermo-reversible dry adhesive to a temperature above the glass transition temperature of the shape memory polymer to cause the shape memory polymer to revert to its original shape, therein causing the dry adhesive layer to return to its original shape. 
   
   
       13 . A method as set forth in  claim 12  wherein the load is about 1 N/cm2 to about 20 N/cm2. 
   
   
       14 . A method as set forth in  claim 12  wherein the glass transition temperature of the shape memory polymer is about 25 to about 200° C. 
   
   
       15 . A method as set forth in  claim 12  wherein the glass transition temperature of the dry adhesive is about −90 to about 200° C. 
   
   
       16 . A method comprising: forming a thermo-reversible dry adhesive comprising: forming a first layer by curing a first component, a second component, and a third component; forming a second layer over the first layer comprising pouring a mixture of a fourth component and a fifth component over the first layer and curing the second layer; and post-curing the first and second layers to form the thermo-reversible adhesive having a curved structure at a first temperature and having a relatively flat structure at a second temperature with a load applied. 
   
   
       17 . A method as set forth in  claim 16  wherein the first component, the second component, and the third component comprise: at least one of a rigid epoxy or a flexible epoxy; and at least one of a crosslinking agent or a catalytic curing agent; wherein the rigid epoxy is an aromatic epoxy having at least two epoxide groups, the flexible epoxy is an aliphatic epoxy having at least two epoxide groups, and the crosslinking agent is one of a multi-amine, an organic multi-carboxylic acid, or an anhydride. 
   
   
       18 . A method as set forth in  claim 16  wherein the first component, the second component, and the third component comprise an aromatic diepoxy, an aliphatic diepoxy, and a diamine. 
   
   
       19 . A method as set forth in  claim 18 , wherein the aromatic diepoxy comprises diglycidyl ether of bisphenol A epoxy monomer with an approximate epoxy equivalent weight of 180; wherein the aliphatic epoxy comprises NGDE; and wherein the diamine comprises poly(propylene glycol)bis(2-aminopropyl)ether with an average molecular weight of 230. 
   
   
       20 . A method as set forth in  claim 16 , wherein the fourth component and the fifth component comprise an aliphatic diepoxy and a diamine, and wherein the components are present in an amount sufficient to provide, upon curing of the second layer, a soft epoxy dry adhesive layer having a glass transition temperature of −90° C. to 200° C. and having a pull-off strength of 1-200 N/cm2.