Adhesive sheet

Abstract

An adhesive sheet is disclosed including a flexible substrate and an adhesive layer formed on at least one of the main surfaces of the flexible substrate. The adhesive sheet further includes a plurality of microscopic holes connecting the opposing surfaces of the sheet and being generally perpendicular to them. Such adhesive sheet is permeable by air and allows good bubble escapability when the sheet is applied to an article. Sufficient permeability of the sheet to air is achieved with microscopic size holes installed in modest areal densities, hence the appearance and functionality of the film surface are not significantly adversely impacted. One intended use of the subject invention is for tinting films used to reduce light transmission in windows for use in buildings and automobiles. In this application visual appearance of the film is paramount. Another intended application of the subject invention is for antireflective film which is applied to electronic computer displays (flat panel, cathode ray tube) to reduce unwanted ambient light reflection and to improve contrast.

1 . An adhesive film comprising a flexible substrate and a pressure-sensitive adhesive coating, wherein
 a. Said flexible substrate has a first surface and a second surface;   b. Said first and second surfaces are opposing each other and being generally parallel;   c. Said pressure-sensitive adhesive coating being adhered to said first surface; and   d. A plurality of microscopic holes are installed each extending at least through said substrate.   
   
   
       2 . Adhesive film of  claim 1  further comprising a layer of material selected from the family of: printing ink, protective coating, or decorative coating; said material being applied to said second surface of said substrate; and wherein said microscopic holes penetrate through said material. 
   
   
       3 . An adhesive film comprising:
 a) A flexible substrate with opposing sides;   b) Pressure sensitive adhesive which is discontinuously coated on at least one side of said substrate to provide areas of the pressure sensitive adhesive interspersed with areas of uncoated substrate; the areas of said substrate which are not coated by adhesive being 5 to 80 percent of the area of one side of said substrate;   
     wherein,
 i) said substrate has a plurality of microscopic holes connecting said substrate sides and being generally perpendicular thereto; 
 ii) transverse dimension of said holes being between about 1 and about 300 micrometers; 
 iii) and the size and the areal density of said holes installed in the portions of the substrate uncoated by said adhesive are chosen so that the adhesive film has an air permeability in the range of 1 to 1000 Gurley seconds. 
 
   
   
       4 . Adhesive film of  claim 3  further including a release liner attached to said adhesive. 
   
   
       5 . Adhesive film of  claim 3  wherein said adhesive is applied to only one side of said substrate and the other side has a finish layer applied onto it; and wherein said microscopic holes penetrate through said finish layer. 
   
   
       6 . A porous transparent adhesive film; said film comprising
 a. a substrate having a plurality of microscopic holes installed therethrough; and   b. a layer of pressure sensitive adhesive applied to one side of said substrate.   
   
   
       7 . A method for fabricating a porous adhesive film comprising the acts of:
 a) Presenting a flexible film substrate having a first surface and a second surface; said first and said second surface opposing each other and being substantially mutually parallel;   b) Applying a layer of adhesive to said second surface;   c) Installing microscopic holes in said substrate by a method selected from a family consisting of mechanical piercing, electric discharge, and laser drilling.   
     wherein said flexible substrate further comprises a finish layer attached to said second surface. 
   
   
       8 . The method of  claim 1  wherein said adhesive is a pressure sensitive adhesive. 
   
   
       9 . The method of  claim 1  wherein said adhesive is a water soluble adhesive. 
   
   
       10 . The method of  claim 1  wherein said adhesive is substantially porous and permeable by air.