US1973571A

US1973571A - Cellulose unit

Info

Publication number: US1973571A
Application number: US634931A
Authority: US
Inventors: Laucks Irving Fink
Original assignee: LAUCKS I F Inc
Current assignee: I F LAUCKS Inc; LAUCKS I F Inc
Priority date: 1932-09-26
Filing date: 1932-09-26
Publication date: 1934-09-11
Anticipated expiration: 1951-09-11

Description

Sept. 11, 1934. I uc s 1,973,571

CELLULOSE UNIT Filed Sept. 26*. 1932 INVENTOR. fr w'rzyJc'rz K A due/E6 ATTORNEYS Patented Sept. 11, '1934 UNlTED STATES PATENT OFFICE I. F. Laucks, Inc., tlon of Washington Seattle, Wasln. a corpora- Application September 26, 1932, Serial No. 634,931

6 Claims.

It has beenheretofore discovered that sulphur derivatives of carbonic acid are water resistanceincreasing agents when incorporated with adhesives embodying either animal or vegetable proteins or both. Viscose,.as one of these sulphur derivatives of carbonic acid, has been proved to be quite eilicient as a water resistance-producing agent when used with such adhesives.

Now, however, it has been discovered that vis- 10 cose in itself is an eflicient adhesive, when proteins are entirely'absent from the composition or present only in minor percentages, when applied to wood and particularly to veneers or used in the manufacture of plywood.

To the accomplishment of the'foregoing and related ends, the invention, then, comprises the features hereinafter fully described, and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative however, of but a few of the various ways in which the principle of the invention may be employed.

In the annexed drawing:

The sole figure is an enlarged section through a laminated wood unit in accordance with the invention.

For the purposes of this disclosure the term viscose may be defined to include all cellulose xanthogenates. The base material of such xanthogenates may be cotton, wood pulp, ground wood, wood flour, purified cellulose, oxycellulose, cellulose partially purified, reverted cellulose, seed coats as soya bean seed coats, straw, etc. These xanthogenates are injgeneral prepared by treatment of the cellulosic material with caustic soda and with carbon bisulphide. It is particularly to be noted that the term viscose, as herein used, is not to be restricted to the one product of pure Bevan.

The use of viscose as an adhesive for wood, and particularly for plywood, has been exemplified by me in the following manner:

Cellulosic material is treated with caustic soda solution of ten per cent or greater concentration for periods varying from less than one hour to several days, the time of treatment being shortened by heating. When the celluloses and hemicellulose originally described by Messrs. Cross 8:

" ,50 celluloses ofthe material are converted to alkali compounds the excess caustic solution may be removed. However, it has been discovered in the course of my experiments that caustic soda in excess of the amount necessary to convert the 5-3 celluloses and hemi-celluloses (if the latter are present) into the corresponding alkali compounds, serves to promote the workable life of the xanthogenate resulting after treatment of the alkali compounds with carbon bisulphide.

When the alkali cellulosic compounds are converted into xanthogenates (viscoses) by any of the well known methods they are ready to be spread on wood panels.

Fir veneer spread with cellulose xanthogenate and assembled into 3-ply or 5-ply panels, for example, and subjected to pressure in the ordinary plywood press, result in fir panels of commercial quality and strength showing considerable water resistance. They may be used for commercial purposes. The product thus manufactured is new in the plywood field and may be described as a wood product composed of individual wood pieces bound together by a glue of cellulosic derivation. It has the advantages of ease of handling of materials during manufacture, of such simplicity that the binder may be made at each individual veneer plant in such quantities as are desired for immediate use. It has the further advantage of cheapness because of the utilization of cheap forms of cellulose. It has the further unique property of providing a bond of cellulosic material for ligno-cellulose material such as wood sheets or blocks. The progressive development of reaction products produces regenerated celluloses and hemi-celluloses. This regeneration of celluloses and/or hemi-celluloses on the glue line (in situ) by the normal process of reversion of cellulose xanthogenates (viscose-s) provides a cellulosic bond for cellulosic material-a cellulosic unit, a much desired result heretofore unattained. The binding material on the glue line being of the same or very closely allied chemical composition, as well as like physical'properties as the material bound, for example wood sheets, provides a finished unit of construction which has most declded advantages in avoidance of the destructive effects of strains which are set up by unequal expansion and contraction of the several component parts of the unit (plywood, for example) when such component parts are of varying chemical composition and unlike physical properties. Such contraction and expansion is inevitable in wood units, due to the changes in moisture content which are constantly in progress. When the material operating as the binder for wood sheets, laid as plywood is made with the grain in adjacent sheets running at right angles each to the other, is of chemical composition closely allied to the chemical composition of the wood sheets, the degree of expansion or contraction of the 1m heating of the panels may be performed in the binding material due to moisture content change will be more nearly the same as that of the wood sheets bound, than is the case when the binder is of very different composition chemically from the composition of the material bound. Thus it 'is shown that my discovery enables the manufacture of laminated structures of cellulosic nature, as for example plywood, which are not subject to the undue internal stresses and strains due to moisture changes and consequently less" subject to surface checking and cracks in interior plies, which not only weaken the units but make them less resistant to moisture transfer,

and also in the case of surface checks seriously.

y detracting from an- .less than than two hours to get maximum strength increases provided that the temperature of 220 F. is attained in the kiln or heating chamber for at least a portion of the period. If desired the ordinary commercial hot press provided the temperatures above named are attained at the glue lines of the panels. The humidity of the kiln or heating chamber should be maintained at a point suchthat the moisture content of the panels is not decreased below 10%, thus avoiding undue checking of tlie plywood.

Other modes of applying the principle of the invention may be employed instead of the one explained, change being madeas regards thereatures herein disclosed, provided the features stated in any of the following claims, or the equivalent of such be employed.

What I claim is: 7

1. Unit composed of wood laminations, adjacent laminations beingbound together by a substantially co-extensive film of an adhesive of reverted cellulose.

2. Unit composed of wood laminations, adjacent laminations being bound together by a substantially co-extensive film of an adhesive of cellulose xanthogenate. I

-3. Unit composed of wood laminations, adja cent laminations being bound together by a substantially co-ex'tensive'film of an adhesive of reaction products of cellulose xanthogenates.

4. A cellulose unit composed of wood laminations laid with the grain of each lamination at right angles to. the grain of the adjacent lamination, adjacent laminations being bound together by a substantially co-extensive adhesive film of reverted cellulose.

5. A cellulose unitcomposed of wood laminations laid with the grain of each lamination at right angles to the grain of the adjacent lamination, adjacent laminations being bound together by a substantially co-extensive film of a cellulose xanthogenate adhesive.

6. A cellulose unit composed of wood laminations laid with the grain of each lamination at right angles to the grain of the adjacent lamination, adjacent laminations being bound together by a substantially co-extensiv'e adhesive film comprising the reaction products of cellulose xanthogenate.

' IRVING FINK LAUCKS.