US2336367A - Paper and process for preparing the same - Google Patents

Description

Patented Dec. 7, 1943 UNITED STATES PATENT OFFICE I rsransupra tzcggglzga ranrsama I Fay H. Osborne, Windsor Locks, Conm, assignor to C. H. Dexter & Sons, Inc.. Windsor Locks, Conn., a corporation of Connecticut No Drawing. Application December 21, 194.2, Serial No. 469.713

4 Claims. (Cl. 92-21) This application is a continuation-in-part of my copending application Serial No. 280,655, filed June 22, 1939.

The present invention relates to the art of paper making and is more particularly concerned with the problem of providing for uniformity of fiber arrangement and distribution in the finished paper web. More specifically, the present invention constitutes an improvement over the process and product disclosed and claimed in my prior United States Patents Nos. 2,045,095 and 2,045,096, issued June 23, 1936.

In these patents I have disclosed an improved,

long-fibered, soft and pliable paper which is characterized by its strength and durability: by its substantial uniformity in texture, weight and thickness; and by its high absorption characteristics; which is substantially free of weak spots and clots; which is very soft and pliable; and which for all practical purposes is lintless.

This type of paper has achieved wide-spread use in industry, particularly for the production of tea bags. as a base for stencils, and for packing and cleaning lenses.

The paper disclosed in my prior patents is formed from vegetable fibers. and particularly from fibers of the Musa family or genus. More particularly, the paper is formed from fibers of Musa temtz'lis. Musa textilz's, in the raw stock, is composed of long structural fibers of pure cellulose encrusted with ligneous material andheld together by gums and waxes. The structural fibers from such stock are more or less uniform in length, the fibers varying from four to seven millimeters and there being no minute fibers which will produce lint in the finished paper. These fibers are relatively cylindrical and have tapered or pointed ends and have little or no tendency to curl or twist so that they do not become entangled or matted but, on the other hand, they will remain separated from one another when suspended in a large volume of water. Ordinary fibers are not suitable for this type of paper. Fibers like linen or cotton tend to. twist together in the process of forming the paper, thereby forming bundles which give a clotty effect in the finished paper. bleachedsulphite) are too short, and therefore give a lint to the finished paper which is unde-.

' ing the process of making the paper, and they Fibers like wood (as are not crushed, shredded, flattened, or frayed. The paper is entirely devoid of all the natural waxes, gums, and ligneous or encrusting constituents present in the original raw stock. The webs, which are of unlimited lengths, are uniform in thickness and in weight throughout, the variation between various portions of a web not amounting in any instance to more than five per cent. The fibers extend in-all directions so that the paper has no grain and therefore it is of equal strength and equal absorbency in all directions.

Fair fiber distribution is attained in following the invention of my prior patents, but I have found some tendency of the fibers to fiocculate, thus'causing non-uniform fiber distribution and arrangement.

It is a prime object of the present invention, therefore, to improve paper of the foregoing character by minimizing fiber flocculation therein and to produce finished webs of this type of paper in which the fibers are uniformly arranged and dispersed, thus enhancing silky appearance, opacity. grain effect and finish. Without employing special precautions, there is a natural tendency of the fibers to fiocculate or agglomerate during the web forming process, to the detriment of the ultimate strength and'appearance of the finished paper product.

Attempts have been made by prior workers in this art to minimize fiber flocculation by employing so-called "corrective" processes including, for instance, the reduction of the average fiber length, hydration of the fibers, and the blending of ground wood with processed pulps. Such procedures, while decreasing fiocculating tendency to some minor degree, all .deleteriously aflect otherwise desirable characteristics in the finished web, such as strength, grain eflect, appearance, stifiness and brittleness.

It has been found. in accordance with the present invention, that the aforesaid desirable characteristics of defiocculation and uniform fiber distribution may be obtained through the incorporation of certain addition agents into the paper stock at any suitable point in the process prior to sheet formation on the screen.

Addition'agents found especially suitable are the locust bean (Ceratonia siliqua) found naturally occurring in Algeria and Cyprus and psyllium seed (Plantago psyllium) which is obtion. The powdered bean as employed in the present invention has the same chemical constituency as the naturally occurring bean, i. e., it has undergone no chemical change in purification. Similarly, the psyllium seed is employed in chemically unaltered form.

Both the locust bean and the psyllium seed possess excellent dispersing properties for paper fibers and either may be used alone for its dispersing and defiocculating function. For some particular characteristics, such as opaqueness and strength, the locust bean is found to be especially suitable. As to other characteristics such as silky appearance and improved finish, the psyllium seed seems to be best suited. A mixture of the two materials provides not only a better fiber defiocculant and more than additive dispersing power but also an agent giving rise to all of the aforementioned additional desirable characteristics such as silky appearance, strength, opaqueness and improved finish.

In the practice of the invention the locust bean defiocculating agent is added to the paper stock as a gelatinous dispersion of the powdered bean in water or other suitable liquid, whereas the psyllium seed deflocculating agent is employed as a water extract of the raw seeds.

It is to be distinctly understood that the defiocculating and dispersing agent disclosed herein are in no sense sizes and when incorporated in the paper stock, in comparatively small proportions, exhibit no size function whatever. In this respect, therefore. the deflocculating and dispersing agents of the present invention are to be carefully distinguished from the usual paper making sizes and fillers such as starches, glues, gelatine, silicates, talc, titanium oxide, chalk, etc. When producing long-fibered paper ordinary sizes leave the paper with an undesired stiffness and brittleness while fillers give a weakening effect to the finished paper. Then, too, the defiocculating and dispersing agents of the present invention are to be distinguished from other well known paper-making chemicals which destroy the absorbent qualities of the paper. In fact, one of the main advantages in the use of the deflocculating agents of the present invention when employed in the production of long-fibered papers is that they have appreciably no effect on the absorbent qualities of the finished product. Furthermore, they are desirable because they do not render the paper stiff or brittle or give any weakening effect.

The proportion of defiocculating agent to fiber in the finished paper is rather small and in no case is the defiocculating agent to be used in amounts sufiicient to produce a sizing effect in the paper. Preferred proportions of powdered locust beans to fiber in the finished paper are psyll um seed aqueous extract solids to fiber in the finished paper are about 0.03% to 0.63% on a weight basis.

Several methods may be employed in preparing the extracts or dispersions of the aforesaid materials for addition tothe paper stock. The

invention, however. is not limited to any particular method or means for preparing the extracts or dispersions and the preferred processes outlined hereinbelow may be varied without digressing from the scope of the invention.

Preparation of locust bean dispersion Twenty pounds of locust beans (in the form of a white powder hereinbefore described) are agitated for thirty minutes in 240 gallons of cold water. The temperature of the mixture is then raised to 90 C. and stirred for thirty minutes at this elevated temperature. A clear liquid dispersion is obtained which, when added to paper fibers in a beater, produces the desired characteristics.

Naturally, the amount of this dispersion to be added to the beater depends on the type of paper desired. It has been found that by adding all of this 240 gallon dispersion to a heater containing 425 pounds of fiber (on the dry basis), the resulting paper is greatly improved in opacity, distribution of fibers, strength and finish. The percentage of locust bean powder to fibers in this instance is 4.70%. When used in making the long-fibered paper described in applicant's United States Patent No. 2,045,095, the percentage of locust bean powder to the water in the head box is 0.00058% since the percentage of fiber to water is 0.0l25%. Thus, effective results are obtained through the use of extremely small quan- Twenty pounds of psyllium seeds (as whole seeds, 1. e. neither ground nor crushed) are stirred into 240 gallons of water at a temperature of approximately C. for a period of about two hours. The mixture is then allowed to cool and it is found that a clear viscous solution results in which the seeds settle and may be separated from the solution by drawing the solution off above the seeds.

Should this extract be evaporated down to dryness, it will be found that the resulting solid residue weights 2 pounds, which is 12 /2% of the weight of the original 20 pounds of whole seeds Preparation of locust bean-psyllium see combination min:

Ten pounds of locust bean powder are mixed in 240 gallons of cold water and agitated at room temperature for approximately thirty minutes.

The temperature is then raised to C. and the resulting hot dispersion is further agitated for thirty minutes. This dispersion is allowed to cool to approximately 80 C. and ten'pounds of psyllium seeds are added thereto and stirred therewith very slowly for a period of approximately two hours. The seeds are allowed to settle an the locust-psyllium mix drawn off.

If all of this 240 gallons of the above mix is added to the paper stock in accordance with the assess? process of applicant's United States Patent No.

2,045,095 under the same conditions as described above in connection with the psyllium extract, then the resulting paper will be improved in many characteristics such as silky appearance, strength, fiber distribution, grain control, opequeness and finish.

In all of the foregoing examples, since the paper-making process is carried out in the closed system shown in United States Patent No. 2,045,095, the percentage of additive based on additive to fiber, will be the same in the head box as in the finished paper sheet.

It will be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit oi my invention.

It is to be further distinctly understood that the present invention is not intended to cover a paper product wherein the addition agents disclosed herein are added to a finished paper sheet as by coating, saturating, etc. Such is to be precluded from the scope of the appended claims. Achievement of the aims of the invention is obtained only when the addition agents are added to the fibrous mix before web formation.

What is claimed is:

l. A porous, long-fibered paper consisting of uncrushed, cylindrical, soft, non-hydrated Mesa tertilis fibers of substantially uniform length uniiormly distributed to leave substantially uniform- 1y spaced openings throughout the area of the paper, the paper being uniform in texture, weight, and thickness throughout, soft and pliable, practically lintless, and highly absorbent, said paper containing 0.08% to 1.25%, based on the weight of fibers, of chemically unaltered psyllium seed aqueous extract solids.

2. A porous, long-fibered paper consisting of uncrused, cylindrical, soft, non-hydrated Muse temtilis fibers of substantially uniform length uniformly distributed to leave substantially uniformly spaced openings throughout the area of the paper, the paper being uniform in texture, weight,

and thickness throughout, soft and pliable, practically lintless, and highly absorbent, said paper containing powdered locust bean and psyllium seed aqueous extract solids, said solids being in chemically unaltered form, the powdered locust beansbeing present in an amount from 0.25% to 5% based on the weight of the paper fibers, and the psyllium seed aqueous extract solids being present in an amount from 0.03% to 0.83% based on the weight of paper fibers.

3. A method or making paper of silky appearance and improved finish which comprises preparing a mix containing fibers of Muse textilis which normally have a-tendency to fiocculate, adding to said mix, before formation of a paper web therefrom, a chemically unaltered aqueous psyllium seed extract, the extract being derived from a quantity of psyllium seeds, said quantity of seeds being, by weight, from 0.5% to 10% of the paper fibers, and then forming a paper web from the resulting fiber mix, said psyllium seed extract, in the amounts indicated, being effective to prevent flocculation of the M usa temtilis fibers during paper formation.

4. A method of making paper of silky appearance and improved finish which comprises preparing a mix containing fibers'of Musa teztilis which normally. have a tendency to fiocculate, adding to said mix, before formation of a paper web therefrom, a dispersion of powdered locust beans and an aqueous extract of psyllium seeds, the locust bean and the psyllium seed extract being in chemically unaltered form, the powdered locust bean being present in an amount of 0.25% to 5% based on the weight of the paper fibers, and the extract being derived from a quantity of psyllium seeds, said quantity of seeds being. by weight, from 0.25% to 5% of th paper fibers, and then forming a paper web from the resulting fiber mix, said powdered locust beans and psyllium seed extract, in the amounts indicated, being effective to prevent flocculation of the Muse temtilis fibers during paper formation.

FAY H. OSBORNE.