US2173130A - Treated and coated paper and process of manufacture thereof - Google Patents

Description

Patented Sept. 19, 1939 TREATED AND COATED PAPER AND PROC ESS F MANUFAOTUBE'THEREOF Nicholas E. Oglesby, Troy, N. Y.

No Drawing. Application July 10, 1936,

Serial No. 90,953

3 Claims. (CI. 91-68) 0 as a flexible covering of high strength and ability to resist the action of water. Another object of the invention is to provide a' flexible product which will not deteriorate rapidly with ago.

Another object of the -lnvention is to provide a paper particularly suitable for hanging and useful in the building trades. Another object of the invention is to provide a paper particularly suited for use as a. covering for boxes, containers and the like. Another object oi the invention is to provide a paper particularly suitable .oilcloth substitutes and the like.

for table covers and the like. Another object of the invention is to provide a paper particularly applicable to manufacture into artificial leather. Another ob-= ject of the invention is to provide a paper having some or all of the characteristics indicated and in condition to receive a coating, for example, of abrasive grain. Another object of the invention is to provide a flexible base adaptable to receive a finishing coating or coatings applied to one or both sides and adapted to cooperate with one or both coatings, for example. varnishes. resins and lacquers. 1

Another object of the invention is to provide a product for one or more of the uses set forth above which is water-resistant. Another object of the invention is to provide a product for one or more of the uses set forth above which shall resist cracking. Another object of the invention is to provide a product of the character indicated, in which the coating shall not readily peel off the backing. Another object of the invention is to provide a process for the production of paper of the type indicated, facilitating rapid production thereof. Another object of the invention is to provide a process of treating paper which plasticizes the paper. Other objects oi the invention are to provide a simple, inexpensive and safe process for the production of the products specified and which can be readily controlled in commercial use. Other objects will help part obvious or in part pointed out hereinafter.

The invention accordingly-consists in the features of construction, combinations of elements, and arrangements 0! parts, and in the several may be controlled.

steps and relation and order of each of said steps to one or more of the others thereof, all as will be lllustratively described herein, and the scope of the application of which will be indi- 5 cated in the following claims.

In carrying out the invention I make use of any knownmachine for the production of paper from stock, as for example, a Fourdrinier machine or a cylinder machine.

I have-found that the correct preparation oi the base paper stock is important and as an illustration of my process. detailed instructions will be given for the manufactureof 40 1b. paper. The paper stock used may be rope, Jute, chemical wood pulp, purified wood pulp, cotton or various combinations of these and other suitable fibres. By way of illustration 9. suitable furnish may consist 0! 60% rope fibre suitably cooked asis known in the art and 40% of a good grade of kraft pulp. The furnish is introduced into a beating engine and the paper stock is beaten to the required degree. By variations in the beating practice, the penetration of the oil, varnish or other material described hereinafter In some cases'it is desirable that there be considerable penetration of the paperbase by the oils or similar treating bodies hereinafter described, while in other cases less penetration is desired, and the oil applied serves primarily to seal the surface pores.

The time of beating required will depend to a considerable extent upon the pulp used and its previous preparation and treatment. In many cases pulp which has been beaten to about a Schopper-Riegler test of degrees and jordaned to 60 degrees will be satisfactory. After the paper pulp has been sumciently beaten, it is run through a Jordan to a Fourdrinier paper machine and the sheet is formed in the usual way. dried in the usual way and taken down in the form of rolls slit to any convenient width. The paper so prepared may be treated with suitable oils as hereinafter described.

Instead of using paper as described and especially where a high wet strength is required in the final product, the paper may be treated as described in co-pending application, Serial No. 89,267 filed July 6, 1936. In this case the paperv stock is beaten to a Schopper-Riegler test of about 30 degrees and the paper is formed; dried and taken down as described. It may then be treated on tub sizing equipment or similar paper treating equipment with a 1% solution of viscose as cellulose which has been pro-treated with sulllclent boric acid to practically neutralize the alkalinity of the viscose solution. Ammonium carbonate may then be added in sufiicient'quantities such that the liberation of carbon dioxide on the dryers may tend to complete the regeneration of the cellulose, such completion of regeneration being subject to control through the amount of ammonium carbonate added.

In lieu of the foregoing treatment, viscose may be added in the beater but I have found that better results are usually obtained by adding the viscose to, the paper after the web is formed. In some cases it is an advantage to add the viscose to the beater in that the fibre furnish may then be beaten to any required'degree to produce the desired resistance to penetration by the treating oils subsequently applied.

As another alternative, instead of adding the viscose as a separate operation after the paper has been removed from the paper machine, the viscose solution may be added after the paper has had only part of the water removed or during its passage through the drying cans by the customary arrangement for tub sizing on a. paper inaking machine.

I may also in some cases treat the paper made, either with or without the wet strength treatment, with a water solution of sorbitol or of triethanolamine oieate to soften or plasticize the backing before the coating operation hereinafter described is carried out.

In lieu of viscose as just described, the paper web may be treated with a solution of glue and glycerine to which has been added paraformalde hyde to tan the glue. The g'lycerine serves as a plasticizer for the very brittle glue and also serves to soften the cellulosic fibres. Instead of glyc erine, triethylene glycol may be used as a plasticizer for the glue, this material like glycerine serving to plasticize both the cellulosic backing and the glutinous adhesive. Instead. of paraformaldehyde I may also use formaldehyde or hexamethylene tetramine or chrome alum to tan the glue. i

In lieu of viscose or the glue-glycerine. treatment previously described, I may treat the paper web with a solution of hide glue, such as for instance a 10% solution of 62 millipoise hide glue and sorbitol in water. In this case thesolution should be applied to the paper web at a ,fiuid product.

Such deieiied linseed oil, soya bean oil and similar semi-drying oils, when dried or set, tend to produce a very flexible and firm Jelly but under ordinary conditions of drying or curing do not set up to give a final product which is as hard or tough as China-wood oil similarly cured, China-wood oil being definitely in the class of drying oils, and subject to severe oxidation and other reactions which eventually result in a comparatively hard brittle film. Paper treated with a controlled quantity of the semidrying oils is well adapted to cooperate with a variety of coating materials as hereinafter explained. The product formed is definitely more flexible than a product similarly made with drying oils and varnishes. While paper treated in accordance with this invention is generally less flexible than that described in co-pending application Serial No. 89,267 filed July 6, 1936, and formed by saturating paper with a water emulsion of semi-drying oils, for many purposes the product made in accordance with the present invention is satisfactory and cheaper. Generally speaking, the process of the present invention is more economical, especially in regard to the quantity of treating oils used.

While the emulsion and alternate processes described in the aforesaid application are usually carried out with porous papers known as saturating papers, the present process may be and more often is carried out with less porous papers, and

may be used to advantage with papers that are relatively resistant to ,oil penetration, as for example, as p'resize and backsize coating treatments.

As an illustration, the treatment of '40 lb. paper will be described in detail. Lighter or heavier papers may, however, be used according to the product desired. The porosity of the paper may vary within limits determined by the product intended, as for instance, the extent of penetration of oil required. H

From considerations of both economy and quality of the product, I often find it advisable to add to the paper, oil treatment to the extent of from about 20 to about 50% of the base paper weight. A preferred oil is heavy blown soya bean oil. A suitable viscosity for the heavy blown soya bean oil used by way of illustration is from temperature f about 125 o 150 F- T paper a about is poises to about 40 poises at 140 F. For

is then dried and may be treated with a water solution containing 10 to 15% formaldehyde to tan the glue. The paper is again dried and calendered. The sorbitol is less subject to changes in effectiveness with changes in the moisture content of the atmosphere and is further lessyolatile and more permanent than glycerine 0r triethylene glycol. For this reason sorbitol is a preferred material for softening glue and for softening the cellulosic sheet and fibres therein.

It will be apparent to those skilled in the art that many variations may be made in the process of forming the paper. Likewise, many variations may be made in the softening process and in the process of producing high wet strength.-.

I have discovered that certain oils whichcure to a flexible jelly state have peculiar advantages for my purpose. While certain non-drying oils such as castor oil find some application in this invention, I prefer to use the semi-drying oils the quantity of oil that will be incorporated in this illustration, the base paper stock before treatment may have an air resistance of about to about as determined by the Gurley densometer.

The oil may be applied by means of the usual tub sizing equipment but I find a double sizing machine such as is used in the waterproof sandpaper industry very satisfactory. The entire coating of the'oil may be applied to one side of the paper and allowed to penetrate more or less into andthrough the paper. 'I usually prefer to add some oil -to both sides of the paper as by means of a double .siz'er, applying about twothirds ofthe oil to the coat side of the paper and one-third of theoil treatment to the back side of the paper. By the coat side of the paper I mean the side to which abrasive grains will be subsequently attached by a suitable binder.

To render the heavy blown oil readily coatable.

such as deielied linseed oil or blown soya been the viscosity is reduced by either heating or addoil. By dejelled linseed oil I mean an oil that ing solvents such as Varnoiene or by a combinahas been produced by partially cracking a Jelled tion of heating and solvents. A suitable temlinseed oil to destroy the firm linseed oil Jelly and perature for the application of the oil or soluproduce instead thereof, a viscous but-.definitdy tion of the: oil is about F. A satisfactory solution is 65% bean oil and 35% Varnolene. In

this particular example about of blown oil Treated paper prepared in accordance with the present invention may be coated with-various coating materials to produce products-tor many applications. The treated paper may be used as a base for suitable coatings to produce a very satisfactory substitute for oilcloth, floor coverings and other uses hereinbeiore specified. Suitable coatings may consist of:

(a) Mixtures ofblown linseed oil, pigments and thinners to which driers mayor may not be added.

(b) Mixtures of lacquersand suitable pigments as, for instance, the nitrocellulose lacquers containing plasticizers, gums, pigments and volatile thinners in suitable proportions.

(0) Many varnishes compounded with pigments. The varnishes may be essentially rosin- China-wood oil varnishes or they may consist of the oil modified glyptals or varnishes prepared from drying oils and the oil soluble phenolaldehyde types oi-resins. I

Prior to applying the pigmented coating I may apply a sizing coat or lacquer or varnish, compatible with the pigmented coating and the treated paper. After the pigmented coating is applied, I may apply a clear coat of lacquer or varnish over the pigmented undercoat. s

A variety of coatings and methods of coating may be used either with or without pi ments or other coloring matter. One advantage 0! my product for oilcloth and floor covering and other like uses is the wet strength treatment added during the fabrication o! the paper. In case of accidental wetting or wetting during washing of the coated surface, the wet strength treatment makes the paper more resistant to disintegration, tearing or breaking when wet.

The paper or the invention is also welladapted as a backing for flexible waterproof sandpaper, but such is described and particularly claimed in my co-pending application Serial No. 90,954

v filed July 16, 1936.

Coatings may be applied to the treated paper prepared in accordance with this invention to produce many other useful articles, for example, certain types of artificial leather may be prepared by coating my treated paper.

' In stating certain theories of the invention, it should be understood that such constitute the best explanation of the results achieved now known to me and the scope of the protection is not to be limited thereby.

It will thus be seen that there has been pr0- vided by this invention a method and an article in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As various possible embodiments might be made of the mechanical features of the above invention and as. the art herein described might be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinbefore set forth is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. Flexible coated paper including a paper backing containing an agent adapted to impart wet strength to the sheet and an agent adapted to soften the sheet, containing semi-drying oil, said semi-drying oil being present to the extent of 20% to 50% of the base paper weight, and a surface coating selected from the group consisting of paints, lacquers, varnishes and resins, said composite article being durable and water resistantand not subject to cracking when bent, the bond between the surface coating and the treated base paper being of a nature to resist cracking and peeling when the article is subjected to flexing. and bending in normal handling and 2. Flexible coated paper .including a paper backing containing an. agent adapted to impart wet strength to the sheet, containing semi-drying 011, said semi-drying oil being present to the extent of 20% to 50% of the base paper weight, and a surface coating selected from the group consisting of paints, lacquers, varnishes and resins, said composite article being durable and watt resistant and not subject to cracking when bent, the bond between the surface coating and the treated base paper being of a nature to resist cracking and peeling when the article is subcoating selected from the group consisting of paints, lacquers, varnishes and resins, said composite article being durable and water resistant and not subject to cracking when bent, the bond between the surface coating and the treated base paper being of a nature to resist cracking and peeling when the article is subjected to flexing and bending in normal handling and use.

NIOHOLASJL OGLESBY.