US 2014/0028772 A1 Digital binder printing
WO 2014/017972 A1 Digital binder printing
Floor Iptech AB
These patent applications describe a method of printing decorative boards and in particular flooring. The inventor is also CEO of Välinge, a leading R&D company in the flooring industry, and both companies are based in Viken, Sweden.
There have been several proposals to print onto laminated board or flooring using ink jet. Traditional printing is only cost efficient in very long runs. However the cost of ink jet printing laminate flooring is around €1/m2 assuming the cost of the ink jet ink used is €100/litre. This is 10 times the cost of ink for conventional printing. In addition ink jet inks are limited by viscosity and therefore the solids contents that can be used.
The solution is to use ink jet heads to form a wet image on the substrate, then apply a powder of resin and pigment, and vacuum off excess powder from the non-image areas. The ink jet head 32 jets a liquid on to the substrate 2 to form the desired image 11 of the rst colour. The liquid can be just water, as long as it remains wet enough for the next step. The substrate typically has a top coating of a thermosetting resin, preferably a melamine formaldehyde.
Next the powder is applied by scattering unit 27, consisting of an embossed drum and an oscillating brush. The powder is a mix of the first colour pigment and melamine formaldehyde. Where the image is wet the binder melts. This ‘image’ is then cured and dried by UV lamp 23. The powder in the non-image areas that was just scattered on the substrate surface is then removed by the vacuum unit 28. The powder that is removed is returned to the feed hopper for the scattering unit.
Other colours can be printed in exactly the same way until the image is complete. The board is then subjected to 40 bar pressure and 160C to cure and form a hard wear-resistant surface.
The cost of the powder reduces the cost of printing to around €0.2 m2, one fifth that of direct printing with ink jet.