Patent GB-332190-A (GB)
Title: Improvements in or relating to processes and apparatus for surfacing sheet material with pigments, varnishes, lacquers or the like
IPC: B05D1/00
Filed: 1929-02-15
Abstract: 332,190. Brown, G. M. Feb. 15, 1929. Coating materials in long lengths.-A process for surfacing sheet material consists in traversing the material past a fixed station over a trough containing a liquid medium on which a film of pigment, varnish or lacquer is floated, in such manner that successive portions in the length of the material come into contact with the liquid and remove the film by movement thereof in relation to the flotation medium in a direction along its surface. The film has sufficient tensile strength to permit it to be drawn along the surface of the liquid without disruption, and consists of pigments in vehicles such as boiled linseed oil or solutions of cellulose esters or ethers, with or without thinning agents and volatile solvents. Varnishes, lacquers, waterproofing solutions or dyes may also be used. The process is particularly applicable to the marbling of paper, in which case supplies of differently coloured paints are deposited on the liquid and agitated to form a marbled film. Portions of the sheet to be coated may be treated with a resist so as to prevent the adhesion of the coating on those portions. The apparatus comprises a tray 10, Fig. 1, in which the flotation medium, for instance water or a solution of Carragheen moss, is contained, a support for the roll 12 of paper, a guide roller 13 and a doctor blade 14 which dips into the liquid in the trough to a depth of about a quarter of an inch. A roller may be used instead of the blade. The paper passes from the doctor to a guide roller 15 and thence to a winding-up roll 16. The film-forming medium is deposited from pots or droppers 17 mounted on a bar 18, each pot having an adjustable outlet, and being adjustable along the bar 18. The agitator comprises a shaft 19 on which are mounted inclined discs 20. The shaft 19 is rotated, and the bar 18 is reciprocated by means of gearing shown in Fig. 2. To obviate the setting up of return currents in the liquid by the dragging action of the paper, an open frame 27, Fig. 2, is immersed to a slight depth in the liquid, and the film formed inside this frame. The agitator shaft 19 may be reciprocated as well as rotated. In some cases the agitator may be omitted, or ,replaced by a comb. The paint may be supplied from large containers by tubes, arranged to give a continuous or intermittent supply. Film-forming materials used may be printer's ink diluted with petrol, waterproof poster colours diluted with petrol, or cellulose lacquers diluted with thinners. Portions of the web may be treated with a resist which will prevent, wholly or partially, adhesion of the film. This resist may be applied by printing or by a stencil, and may consist of ink, water, or a sugar solution. Textile material or sheet material in general may be coated by this method. Separate sheets may be coated in a continuous operation by means of grippers on a rotating cylinder or the sheets may be carried bv endless bands. The film may be taken off the flotation-medium by a transfer roller, and applied to the paper &c. by this roller. Specifications 130,883 ; and 331,201, [Class 95, Paints &c.], are referred to.