Sealing of inscriptions on plastics

Abstract

The present invention relates to the sealing of inscriptions on plastics which have been produced by means of lasers on the plastic surface.

1 . Process for the permanent and abrasion-resistant coloured inscription and/or marking of plastics, characterised in that the bleeding-out or efflorescence of the colorants and/or absorbers in the plastic is prevented by sealing the laser-inscribed areas with a transparent polymer during the inscription process or immediately thereafter.  
   
   
       2 . Process for the permanent and abrasion-resistant coloured inscription and/or marking of plastics according to  claim 1 , characterised in that the polymer has a glass transition temperature of ≧90° C.  
   
   
       3 . Process for the permanent and abrasion-resistant coloured inscription and/or marking of plastics according to  claim 1 , characterised in that the sealing layer consists of the polymers of styrene, of vinyl chloride, of methyl methacrylate or hydroxy-functional acrylates, polyvinyl fluoride.  
   
   
       4 . Process for the permanent and abrasion-resistant coloured inscription and/or marking of plastics according to  claim 1 , characterised in that the polymer layer has thicknesses of 1-10 μm.  
   
   
       5 . Process for the permanent and abrasion-resistant coloured inscription and/or marking of plastics according to  claim 1 , characterised in that the marking is carried out by an indirect inscription process.  
   
   
       6 . Process for the permanent and abrasion-resistant coloured inscription and/or marking of plastics according to  claim 1 , characterised in that the inscription is carried out using a laser and the sealing is carried out in one step.  
   
   
       7 . Process for the permanent and abrasion-resistant coloured inscription and/or marking of plastics according to  claim 1 , characterised in that, in a 2-step process, firstly the inscription is carried out using a laser and immediately subsequently, in a second step, the sealing of the inscribed areas is carried out.  
   
   
       8 . Process for the permanent and abrasion-resistant coloured inscription and/or marking of plastics according to  claim 1 , characterised in that use is made of a layer system which consists of at least three superjacent layers, where the first layer is a support film which is transparent to laser light, to which the laser light-sensitive energy absorber layer is applied or into which the energy absorber is incorporated, subsequently the separation layer and the sealing layer, and, as the final layer, the inscription medium comprising colorant and optionally polymer component or an inscription medium already comprising the sealing polymer, where the inscription medium is introduced into the plastic surface under the action of laser light during the inscription/marking.  
   
   
       9 . Process for the permanent and abrasion-resistant coloured inscription and/or marking of plastics according to  claim 7 , characterised in that the inscription is carried out using a layer system consisting of a support film which is transparent to laser light and the energy absorber layer and the inscription medium as separate layers or a layer system consisting of support film and a layer consisting of a mixture of inscription medium and energy absorber or a layer system consisting of a support film into which the energy absorber is incorporated and the inscription medium, and the layer system is marked using a laser, during which the inscription medium is transferred to the softened plastic, and, in the second step, the sealing is carried out using a layer system consisting of a support layer which is transparent to laser light, a laser-sensitive absorber layer or a support film into which the energy absorber is incorporated, a separation layer and a sealing layer and irradiated using a laser, during which the requisite energy is transferred via the energy absorber layer to the separation layer, which softens and thus transfers the sealing layer to the plastic.  
   
   
       10 . Process for the permanent and abrasion-resistant coloured inscription and/or marking of plastics according to  claim 1 , characterised in that use is made of a layer system which consists of at least three superjacent layers, where the first layer is a self-absorbent support film which is transparent to laser light, to which the separation layer and the sealing layer and, as the final layer, the inscription medium comprising colorant and optionally polymer component or an inscription medium already comprising the sealing polymer are subsequently applied, with the inscription medium being incorporated into the plastic surface under the action of laser light during the inscription/marking.  
   
   
       11 . Process for the permanent and abrasion-resistant coloured inscription and/or marking of plastics according to  claim 7 , characterised in that, for the inscription, use is made of a layer system consisting of a self-absorbent support film which is transparent to laser light and a layer consisting of a mixture of inscription medium and energy absorber or a layer system consisting of a support film into which the energy absorber is incorporated and the inscription medium, and the layer system is marked using a laser, during which the inscription medium is transferred to the softened plastic and, in the second step, the sealing is carried out using a layer system consisting of a support layer which is transparent to laser light, a laser-sensitive absorber layer or a support film into which the energy absorber is incorporated, a separation layer and a sealing layer and irradiated using a laser, during which the requisite energy is transferred via the energy absorber layer to the separation layer, which softens and thus transfers the sealing layer to the plastic.  
   
   
       12 . Plastics which have a sealed marking and/or inscription by the process according to  claim 1.