US1633738A - Pulp fiber - Google Patents

Description

Patented June 28, 1927.

" UNITED ,STATES- PATENT OFFICE.

rannnaretxnarr rrsn, aria, or SAN, rnanersco, CALIFORNIA.

runr FIBER.

No Drawing.

This invention relates to mechanical pulp and more particularly to a'special fiber prov d,uced in mechanical pulp.

Ill

. pulp or the paper made therefrom, either due to the presence of such substances or to chemical changes in these non-cellulose constituents. In the production of mechanical pulp, such characteristics as freeness, uniformity, strength, color, resin content and finish. are of well known importance, but the strength, color and finish of the pulp largely determine its value. Obviously, the longer, finer and more flexible the fibercan be made, the less chemical pulp need be mixed with it and a white color and smooth impervious finish will adopt such pulp for new uses.

It is thus an object of my invention to produce amechanical pulp fiber of increased strength, and substantially white color and which is permeated or treated-with a natural size derived from consituents of the wood.-

It is a further object of my invention to produce in mechanical pulp a uniform fiber. A still further object of my invention isto provide an improved product wherein the insoluble resinous constituents are not only evenly distributed, but are caused to penetrate the individual fibers,'so that the paper produced therefrom has a substantially impervious or sized surface.

In other words, it is an object of this invention to provide a process for so treating wood, that the fibers produced therefrom may be separated without injury and in a condition in which it may be run into a substantially sized paper, without the usual ad dition of sizing materials now commonly used.

In carrying out my invention, ,I produce a fiber from resin-bearing cellulose material which is whiter than the natural fiber and permeated with a natural preservative from the material itself.

It has heretofore been proposed to steam wood under high pressure before grinding; to boil wood, at an elevated temperature and Application filed May 24,

1926. Serial No. 111,458.

pressure for approximately six hours and also to cook wood for three or four hours under pressure with a strong caustic soda solution. It has not been possible to commercially produce, by these methods, a paper, in which color and surface texture combined with strength of fiber are important considerations. e

In previous applications, Serial Numbers 42960 and 42961, filed July 11, 1925,.1 have described processes for treating plant material and for the production of pulp wherein use is made of the volatile and other solvent extractives of the material with and without alkali. I have now found that by regulating the length of time the wood is under treatment, preparatory to grinding or separating by other mechanical means, as well as the amount of alkali added to the treatingliqnor, and the pressure and'temperature emplyed, I can produce a fiber of the decidedly beneficial characteristics above stated. For example, when treating wood averaging eight inches in diameter, I have found that a preliminary treatment for about three lent of one pound ofcaustic potash per cord of wood, will so act on the wood that when it is ground in the usual way, the desired character of fiber is'produced. By so regulating this treatment, it appears that the insoluble resinous constituents of the wood are softened and uniformly distributed throughout the fiber of the wood and they permeate the individual fibers, so that when the pulp is run into paper, the latter has a smooth, substantially impervious surface. Additional sizing materials are thus not required for making certain grades of paper. Moreover, I have found that when wood so treated is ground, it contains substantially no wood flour.

The wood in the usual or any desired lengths is placed in a cylinder or other suitable container and the air is exhausted, in order to allow quick penetration of the liquor. A liquor, consisting of water conhours with 'a liquor. containing the equivataining a relatively small amount of caustic ficient to neutralize the acids without attackingthe lignin of the wood. The liquor should be heated,'preferably to about 250 F. before it is introduced into contact with the wood, and this temperature is preferably maintained for three to four hours. To secure the best results, the liquor is circulated from the top to the bottom of the container, but'this feature forms no part of the resent invention.

The liquor penetrates the wood and causes the or some of the resinous constituents which are removed from their natural location in the wood, to penetrate theindividual fibers. The acidspresent 'or formed are neutralized, at least to an extent which does not interfere with the production of the desired white color. The desired white color being produced by the treatment described, it is not necessary for certain grades of paper to bleach the pulp formed by the mechanical separation of the fiber. The lignin is not attacked by the liquor.

The wood, after having been so treated, is

ground or otherwise separated into fibers. When made intopaper, it is found that, due to the natural size with which the fibers are impregnated and probably to the condition in whlch the lignin is left, the paper has a smooth, substantially impervious surface,

40 to do with the individual fiber which as described is unusually long and uniform, of good color and strength, substantially free from wood flour and impregnated or treated with a natural size of the wood.

The benefits to be derived from my present invention will be apparent, in that this mechanical fiber may be used for the production of paper with a strength, color and finish equivalent to that of such papers now produced from ground wood with the addition of a considerable proportion of chemical or sulphite pulp and the addition of sizing materials is wholly. or very largely eliminated.

The term substantially white as used in the following claims is intended to mean,

white having reference to the color of the 3. A pre-treated fiber produced from cellu losic resin-bearing material, substantially white in color and evenly permeated with a natural preservative of the material from which the fiber is made.

4. A pro-treated fiber mechanically produced from cellulosic resin-bearing material having a color'lighter than that of the natural fiber, permeated with resins, and having its natural content of lignin, the .color being produced before grinding.

- 5. As a new article of manufacture, pretreated ground wood fiber of high strength and of a color lighter than that of the natural fiber, and uniformly impregnated with the insoluble resins of the wood.

6. As a new article of manufacture, pretreated ground wood fiber of high strength and light color and rendered substantially impervious by rearrangement of the insoluble resins of the wood.

7. As a new article of manufacture, pretreated wood fiber, mechanically produced, having high strength and light color and adapted to produce a substantially sized paper without the addition of sizing ingredients.

8. As a new article of manufacture, pretreated ground wood fiber, having a color lighter than that of the natural fiber and adapted for the production of sized paper without the addition of other pulp fiber.

9. As a new article of manufacture, pretreated ground wood fiber, having a color lighter than that of the natural fiber and adapted for the production of a smooth impervious surfaced paper without the addition of sizing material.

In testimony whereof I afiix my signature.

FREDERICK KN APP FISH, JR.