Photosensitive stencils and methods

Abstract

A photosensitive stencil includes a porous stencil carrier that can be a sheet of woven material with crisscrossing filaments. The stencil carrier is coated with a photopolymer emulsion that is water based to form a stencil blank. In use, a light mask is disposed atop the stencil blank. The light mask can be contained on a sheet of paper or a transparent film. Alternatively the stencil blank is fed through an inkjet printer and the light mask is printed directly onto the stencil blank using common inks. The stencil blank is then exposed to light for a few minutes, which cross-links the photopolymer emulsion in unmasked regions. After exposure, the stencil blank is developed by being washed out with water. The water removes emulsion and adhesive, where present, within areas that were masked by the light mask, revealing open or open regions through which ink or paint can be applied.

What is claimed is: 
     
         1 . A method for making a stencil blank for subsequent use in making a final stencil from the stencil blank, said method comprising:
 a) providing a support carrier having a smooth flat surface;   b) pre-coating the smooth flat surface of the support carrier with a film of photosensitive emulsion for forming a pre-coated emulsion film having a smooth flat surface mirroring the smooth flat surface of the carrier;   c) applying a stencil carrier to the pre-coated emulsion film, said stencil carrier having openings sized to pass art media such as ink, paints, pastes and fillers;   d) applying a primary coating of photosensitive emulsion to the stencil carrier so that it permeates the openings of the stencil carrier and bonds with the pre-coated emulsion film,
 wherein said photosensitive emulsion used for the pre-coated emulsion film and the primary coating is soluble in water in its native state and being formulated to become insoluble to water when exposed to light during the subsequent use of the stencil blank, thereby becoming firm and fixed in the stencil carrier; 
   e) applying an adhesive on the primary coating of photosensitive emulsion; and   f) applying a protective release sheet over the adhesive.   
     
     
         2 . The method as claimed in  claim 1 , wherein applying the stencil carrier is performed before the pre-coated emulsion film has dried. 
     
     
         3 . The method as claimed in  claim 1 , wherein said adhesive has an adhesive strength sufficient, during a subsequent use of said final stencil, to stick to a surface to be decorated but being removable from the surface after decoration. 
     
     
         4 . The method as claimed in  claim 1 , wherein the adhesive comprises a pressure sensitive adhesive. 
     
     
         5 . The method as claimed in  claim 1 , wherein the adhesive comprises a substantially continuous film of adhesive. 
     
     
         6 . The method as claimed in  claim 5 , wherein said substantially continuous film of adhesive is photosensitive. 
     
     
         7 . The method as claimed in  claim 1 , wherein the adhesive comprises an array of microdots of adhesive. 
     
     
         8 . The method as claimed in  claim 7 , wherein the microdots are substantially embedded within the primary photosensitive emulsion coating. 
     
     
         9 . The method as claimed in  claim 1 , wherein the stencil carrier comprises a woven material and the openings of the stencil carrier are defined by crisscrossing filaments of the woven material. 
     
     
         10 . The method as claimed in  claim 1 , wherein the stencil carrier comprises a non-woven material and the openings of the stencil carrier are formed by micro perforations extending through the non-woven material. 
     
     
         11 . The method as claimed in  claim 1 , wherein the photosensitive emulsion comprises a photopolymer emulsion. 
     
     
         12 . The method as claimed in  claim 1 , wherein the photosensitive emulsion comprises a photopolymer emulsion including a polyvinyl alcohol with pendent styrylpyridinimm emulsion (PVA SbQ emulsion). 
     
     
         13 . The method as claimed in  claim 1 , wherein the photosensitive emulsion comprises a photopolymer emulsion including selected dyes for enhancing the sensitivity of the photopolymer emulsion. 
     
     
         14 . The method as claimed in  claim 1 , wherein the photosensitive emulsion comprises a photopolymer emulsion including light initiators for enhancing the sensitivity of the photopolymer emulsion. 
     
     
         15 . The photosensitive stencil blank as claimed in  claim 1 , wherein the photosensitive emulsion is formulated to become insoluble to water when exposed to radiation within a spectrum of visible light. 
     
     
         16 . The photosensitive stencil blank as claimed in  claim 15 , wherein the spectrum comprises wavelengths greater than about 400 nanometers. 
     
     
         17 . A method of forming a stencil comprising:
 a) obtaining a photosensitive stencil blank made by the method of  claim 1 , wherein a primary side of the stencil blank is defined by the adhesive coating and is intended to be facing a surface to be decorated and wherein a secondary side of the stencil blank is defined by the pre-coated emulsion film;   b) removing the support carrier;   c) creating a light mask over a selected portion of the stencil blank on its secondary side thereby forming a light-masked stencil blank;   d) exposing the light-masked stencil blank to light, the exposure rendering unmasked portions of the photosensitive emulsion non-soluble in water, thereby creating a light-exposed stencil blank;   e) removing the protective release sheet from the adhesive;   f) developing the light-exposed stencil blank with water to dissolve and remove said selected portion of the photosensitive emulsion covered by the light mask to create a final stencil with the stencil carrier and the openings thereof being exposed within the selected portion; and   g) drying the stencil.   
     
     
         18 . The method as claimed in  claim 17 , wherein creating the light mask includes passing the stencil blank through an ink jet printer like a sheet of paper and forming said light mask by the ink of the ink jet printer on the smooth flat surface of the pre-coated emulsion film. 
     
     
         19 . The method as claimed in  claim 17 , wherein creating the light mask includes placing a paper or a transparent filmic material provided with a mask on the pre-coated emulsion film. 
     
     
         20 . The method as claimed in  claim 17 , wherein the protective release sheet over the adhesive coating of the stencil blank is maintained on the adhesive coating during creating the light mask. 
     
     
         21 . A method for making a stencil blank for subsequent use in making a final stencil from the stencil blank, said method comprising:
 a) providing a support carrier having a smooth flat surface;   b) pre-coating the smooth flat surface of the support carrier with a film of photosensitive emulsion for forming a pre-coated emulsion film having a smooth flat surface with no concavities mirroring the smooth flat surface of the support carrier, wherein said smooth flat surface of the pre-coated emulsion film functions both as a light-mask receiving surface during the subsequent use of the stencil blank for making a final stencil and as a primary surface of the final stencil to cling to a surface to be decorated due to the smooth surface without the need for adhesive;   c) applying a stencil carrier to the pre-coated emulsion film, said stencil carrier having openings sized to pass art media such as ink, paints, pastes and fillers; and   d) applying a primary coating of photosensitive emulsion to the stencil carrier so that it permeates the openings of the stencil carrier and bonds with the pre-coated emulsion film, wherein said photosensitive emulsion used for the pre-coated emulsion film and the primary coating is soluble in water in its native state and being formulated to become insoluble to water when exposed to light during the subsequent use of the stencil blank, thereby becoming firm and fixed in the stencil carrier.   
     
     
         22 . A method for making a stencil blank for subsequent use in making a final stencil from the stencil blank, said method comprising:
 a) providing a support carrier having a smooth flat surface;   b) applying an adhesive coating on the smooth flat surface of the support carrier;   c) applying a stencil carrier to the adhesive coating, said stencil carrier having openings sized to pass art media such as ink, paints, pastes and fillers; and   d) applying a coating of photosensitive emulsion to the stencil carrier so that it permeates the openings of the stencil carrier and bonds with the pre-coated emulsion film, wherein said photosensitive emulsion is soluble in water in its native state and being formulated to become insoluble to water when exposed to light during the subsequent use of the stencil blank, thereby becoming firm and fixed in the stencil carrier.   
     
     
         23 . A method of forming a stencil comprising:
 a) obtaining a photosensitive stencil blank made by the method of  claim 22 , wherein a primary side of the stencil blank is defined by the adhesive coating and is intended to be facing a surface to be decorated;   b) creating a light mask over a selected portion of the stencil blank on its primary side thereby forming a light-masked stencil blank;   c) exposing the light-masked stencil blank to light, the exposure rendering unmasked portions of the photosensitive emulsion non-soluble in water, thereby creating a light-exposed stencil blank;   d) developing the light-exposed stencil blank with water to dissolve and remove said selected portion of the photosensitive emulsion covered by the light mask to create a final stencil with the stencil carrier and the openings thereof being exposed within the selected portion; and   e) drying the stencil.   
     
     
         24 . The method as claimed in  claim 23 , wherein creating the light mask includes passing the stencil blank through an ink jet printer like a sheet of paper and forming said light mask by the ink of the ink jet printer on the primary side of the stencil blank. 
     
     
         25 . The method as claimed in  claim 23 , wherein creating the light mask includes placing a paper or a transparent filmic material provided with a mask on the primary side of the stencil blank.