Embossable thermoplastic polyester film and method for producing the film

Abstract

A directly embossable, coated polyethyleneterephthalate film including a dry, uniaxially oriented PET film, and a coating applied to the PET film, wherein the coating and the PET film have as a composite been transversely stretched, the coating resin being capable of impregnating the PET surface on drawing, rendering the film surface susceptible to embossing under pressure and the coating having low heat sealability and a method of producing a coated, directly embossable polyethyleneterephthalate film.

1 .- 15  (Cancelled)  
     
     
         16 . A method of producing a coated, directly embossable polyethyleneterephthalate (PET) film comprising: 
 stretching a PET film to form a uniaxially oriented PET film;    drying the uniaxially oriented PET film;    coating at least one surface of the uniaxially oriented PET film with an aqueous solution of an organic material; and    rendering at least one surface of a resulting coated uniaxially oriented PET film susceptible to direct embossing by impregnation of the surface of the uniaxially oriented PET film with at least a portion of the coating by transverse stretching the coated uniaxially oriented PET film.    
     
     
         17 . The method of  claim 16 , wherein the PET base film is co-extruded and forms at least two layers.  
     
     
         18 . The method of  claim 16 , wherein the PET film has a thickness of about 4.5 μm to about 60 μm.  
     
     
         19 . The method of  claim 16 , wherein the PET film contains particles.  
     
     
         20 . The method of  claim 19 , wherein the particles are selected from the group consisting of silica, alumina, calcium carbonate and mixtures thereof.  
     
     
         21 . The method of  claim 19 , wherein particles are present in the amount of about 0.005 wt % to about 0.6 wt %, based on the weight of the PET film.  
     
     
         22 . The method of  claim 16 , wherein the PET film is stretched in an amount of about 3.4 to about 5.4 times.  
     
     
         23 . The method of  claim 16 , wherein the coated PET film is stretched in an amount of about 3.3 to about 4.6 times in the transverse direction.  
     
     
         24 . The method of  claim 16 , wherein the coating is formed from a material selected from the group consisting of a non-crosslinked polystyrene-acrylic emulsion and non-crosslinked polyester dispersion.  
     
     
         25 . The method of  claim 16 , wherein the coating has a thickness of about 0.1 μm to about 0.4 μm.  
     
     
         26 . The method of  claim 16 , wherein the co-extruded layers comprise a polyester layer and a co-polyester layer.  
     
     
         27 . The method of  claim 16 , wherein the co-polyester layer is formed from isophthalic acid or a derivative of cyclohexane dimethanol.  
     
     
         28 . The method of  claim 16 , further comprising embossing selected surface portions of the PET film under pressure.  
     
     
         29 . The method of  claim 16 , wherein the co-polyester layer has a thickness between about 0.1 μm and 3.0 μm.  
     
     
         30 . The method of  claim 29 , wherein the co-polyester layer has an upper surface contacting the coating and has a roughness Ra<about 40 nm.  
     
     
         31 . A method of producing a directly embossable substrate having low heat sealability comprising: 
 inline coating a uniaxially oriented PET film with about 0.1 μm to about 0.4 μm in thickness of a non-crosslinked polystyrene-acrylic emulsion or non-crosslinked polyester dispersion;    drying the coating; and    transverse stretching the resulting coated film.