Transparent fibrous sheets and process for making
AssigneeAndrews Paper & Chemical Co., Inc.
InventorsPeter Muller, Henry Mustacchi
Life of this patent
Estimating the term…
Abstract
A transparent, non-stratified, three dimensional resin reinforced fibrous sheet and the process for its preparation is disclosed. A fibrous sheet is impregnated or coated with one or more tri or higher functional monomers that can be polymerized in-situ to form three dimensional polymer resins, in close contact with the fibrous material of the sheet. A transparentized fibrous sheet results which is resistant to water and alcohols, highly and evenly translucent and useful as tracing media vellum as well as a translucent base for sensitizing with reprographic coatings.
Claims20
The method of transparentizing fibrous cellulosic sheets, which comprises:
- providing a sheet of fibrous cellulosic material for transparentizing and which comprises a plurality of discrete cellulosic fibers which are disposed so that at least a portion of said fibers are bonded together at cross-over points, forming voids between the fibers at non-crossover points;
- applying to a surface of the sheet a monomer of the formula:
- ##STR6## wherein R.sub.1 is selected from the group consisting of hydrogen, alkyl, aralkyl, hydroxyalkyl and carboxyl;
- R.sub.2, R.sub.4 and R.sub.6 each represent alkylene;
- R.sub.3, R.sub.5 and R.sub.7 each represent a monovalent moiety selected from those of the formula:
- --CH.dbd.CH.sub.2, ##STR7## and --CH.dbd.CH--R.sub.8 wherein R.sub.8 is selected from the group consisting of alkyl and phenyl;
- and X, Y and Z each represent a divalent moiety of the formula:
- ##STR8## wherein B is selected from oxygen and a group of the formula --NH--;
- in admixture with a thermoploymerization catalyst;
- evenly distributing the applied mixture of monomer and catalyst so as to fill voids in the sheet with the mixture of monomer and catalyst by wet-packing the applied to sheet in a roll under tension for a period of time sufficient to achieve said distributing;
- and
- thermally polymerizing the monomer in the voids by heating the wet-packed roll to a temperature sufficient to activate the catalyst and dissipating excessive heat of polymerization into the environment of fibrous material to prevent spontaneous polymerization from overheating.
A process of transparentizing a fibrous cellulosic material, which comprises:
- applying a monomer having 3 ethylenically unsaturated radicals bonded to one common carbon atom to a cellulosic fibrous web in the presence of a thermopolymerization catalyst;
- winding the web in a tight roll after application;
- storing the roll below the polymerization temperature for the monomer until the mixed monomer and catalyst have impregnated the web;
- and
- then exposing the roll to an elevated temperature sufficient for polymerization of the monomer to take place under controlled conditions and dissipating excessive heat of polymerization into the environment of fibrous material to prevent spontaneous polymerization from overheating.
Dependencies are inferred from the claim text.