Closing liquid for security closures

Abstract

The invention relates to a sealing liquid for sealing mailpieces containing water and a penetration agent, to the uses thereof and to letter-closing devices and franking machines containing such a sealing liquid.

1 - 10 . (canceled) 
   
   
       11 . A sealing liquid for sealing mailpieces, comprising water and a safety additive being substantially not visible by immediate observation. 
   
   
       12 . The sealing liquid according to  claim 11 , wherein said safety additive is selected from the group consisting of luminescent substances, peptides, proteins, nucleic acids, and low-molecular inorganic or organic substances different from other components of the sealing liquid. 
   
   
       13 . The sealing liquid according to  claim 11 , wherein said safety additive is a nucleic acid with 2 to 50 nucleotides. 
   
   
       14 . The sealing liquid according to  claim 11 , which comprises:
 a) 50 to 99.9 wt.-% water;   b) 0 to 10.0 wt.-% penetration agent;   c) 0 to 10.0 wt.-% wetting agent;   d) 0 to 10.0 wt.-% stabilizer and/or buffer;   e) 0 to 5.0 wt.-% dyes;   f) 0 to 5.0 wt.-% aromatic substances;   g) 0 to 10.0 wt.-% biocides and/or fungicides and/or other usual auxiliary substances;   h) 0.0001 to 10.0 wt.-% safety additive;   with the components a) to h) adding up to 100 wt.-%.   
   
   
       15 . The sealing liquid according to  claim 14 , which comprises:
 a) 70 to 99.0 wt.-% water;   b) 1.0 to 30.0 wt.-% penetration agent;   c) 0 to 3.0 wt.-% wetting agent;   d) 0 to 3.0 wt.-% stabilizer and/or buffer;   e) 0 to 2.0 wt.-% dyes;   f) 0 to 1.0 wt.-% aromatic substances;   g) 0 to 1.0 wt.-% biocides and/or fungicides and/or other usual auxiliary substances;   h) 0.0001 to 2.0 wt.-% safety additive.   
   
   
       16 . The sealing liquid according to  claim 15 , which comprises:
 a) 80 to 99.0 wt.-% water;   b) 1.0 to 20 wt.-% penetration agent;   c) 0.01 to 1.0 wt.-% wetting agent;   d) 0.01 to 2.0 wt.-% stabilizer and/or buffer;   e) 0.01 to 1.0 wt.-% dyes;   f) 0.01 to 0.1 wt.-% aromatic substances;   g) 0 to 0.1 wt.-% biocides and/or fungicides and/or other usual auxiliary substances;   h) 0.0001 to 2.0 wt.-% safety additive.   
   
   
       17 . The sealing liquid according to  claim 15 , wherein component h) amounts to 0.0001 to 0.1 wt.-% safety additive. 
   
   
       18 . A method of sealing a mailpiece, comprising:
 providing a mailpiece envelope with a gummed flap;   wetting the flap or an area of the mailpiece envelope opposite the folded flap with a sealing liquid according to  claim 11  with a defined laterally inhomogeneous distribution of the sealing liquid and/or of the safety additive; and   subsequently folding the flap and pressing the flap against an opposed surface of the mailpiece envelope.   
   
   
       19 . The method according to  claim 18 , wherein the mailpiece is a letter and the mailpiece envelope is a letter envelope. 
   
   
       20 . The method according to  claim 18 , which comprises performing the wetting and folding steps with an automated letter-closing device. 
   
   
       21 . A letter-closing device, comprising:
 a tank containing a sealing liquid according to  claim 11 ;   a wetting arm connected to said tank and configured to discharge sealing liquid from said tank and transferring discharged sealing liquid to a mailpiece inserted in the letter-closing device, wherein the sealing liquid is applied on a gummed flap or on a section opposite the gummed flap when the flap is folded onto the mailpiece with a defined laterally inhomogeneous distribution of the sealing liquid and/or of the safety additive.   
   
   
       22 . A franking device, comprising a letter-closing device according to  claim 21 . 
   
   
       23 . A mailpiece, comprising a mailpiece envelope having a flap with a gumming, wherein the flap is sealed by wetting the gumming with a sealing liquid according to  claim 11 , folding the flap, and pressing the flap with the gumming against the mailpiece envelope, and wherein the safety additive is disposed with a defined laterally inhomogeneous distribution in the section of the gumming. 
   
   
       24 . A method of detecting an unauthorized opening of a mailpiece, wherein the mailpiece had been sealed with a sealing liquid according to  claim 11  and with a laterally inhomogeneous distribution of the safety additive, and method comprises: detecting and/or indicating the laterally inhomogeneous distribution of the safety additive and automatically comparing laterally inhomogeneous distribution to a laterally inhomogeneous reference distribution.