Method and apparatus for pattern impregnation of a porous web
AssigneeNPD Corp.
InventorLawrence S. Bogardy
Life of this patent
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Abstract
A method and apparatus for impregnating a porous web with a chemical. The impregnating method includes applying a vacuum to one side of the web sufficient to evacuate air from the web, applying impregnating chemical into the web in a selected pattern on the same side of the web, followed by drying the web. The apparatus includes a vacuum chamber for evacuating air from the web, a manifold for applying the impregnating chemical into the web located on the same side of the web as the vacuum chamber and a stencil for restricting the application of the chemical to selected areas of the web.
Claims37
An impregnator for applying a chemical to a porous web, while said web travels in a prescribed path through said impregnator, comprising:
- (a) vacuum means for withdrawing air from the surface of and within the web;
- (b) treatment means for applying chemical to said web, wherein said treatment means is positioned along said prescribed path after said vacuum means said treatment means being located on the same side of said web as said vacuum means;
- and
- (c) pattern means mounted between said treatment means and said web, for restricting the application of said chemical onto said web to preselected areas of said web.
An apparatus for impregnating the surface of a web with a liquid in the form of a pattern, comprising a vacuum chamber having a suction wall with one or more openings therein;
- means for pulling and controlling a vacuum on said vacuum chamber;
- an impregnating chamber adapted to hold the liquid impregnant, said chamber having an exit wall with one or more openings therein, the exit wall being substantially an extension of the suction wall of the vacuum chamber;
- a pattern belt having an inner surface and an outer surface and perforations in the configuration of the desired pattern, said belt being mounted over the outside of said vacuum and impregnating chambers and being substantially unperforated except in the area of said pattern;
- means for moving the pattern belt past first the suction wall of the vacuum chamber and then the exit wall of the impregnating chamber, with the inner surface of the belt being in sealing engagement with the outside surfaces of both said walls;
- means for pressing the fibrous web to be treated against the outer surface of said pattern belt;
- and means for conveying said web past said suction and exit walls in synchrony with said pattern belt.
A method of impregnating a porous web with a liquid in a pattern, comprising the following steps:
- (a) placing the web in facing engagement with the outer surface of a sheet of liquid-impervious material having perforations therein in the configuration of the desired pattern, said sheet being substantially unperforated, except in the areas of said pattern;
- (b) applying vacuum to the inner surface of the sheet, sufficient to evacuate air from the pores of the web in those areas of the web exposed to the perforations in the sheet said inner surface being located opposite said outer surface and on the opposite side of the sheet thereof;
- (c) applying the impregnant liquid to the inner surface of the sheet under a pressure sufficient to force the liquid through the perforations in the sheet and into the evacuated pores of the web;
- and
- (d) drying the web.
Dependencies are inferred from the claim text.