US1914163A - Art of sizing - Google Patents

Description

PM Jam 13, 1933,

UNITED STATES wnm RANDALL, O1! WAT'EB'VILLE MAINE, ABSIGHOB, BY HESNE assmmms, 1'0 mum TRUST OOKPANY, OI PORTLAND, MAINE, A CORPORATION 01 Km TRUSTEE ART SIZING Io Drawing. Application fled June 24,

5 has been conspicuously apparent where such stocks have been used in die forming operations as by suction or pressure deposit on perforate or foraminous moulding dies.

The general problem has been to introduce the rosin, wax, paraflin, or other sizing into the pulp in such dispersed state that it would not coa late or otherwise gather in particles on the ie and thus clog its perforations and retard or block its efliciency.

Previous methods have involved the saponification or emulsification of the size, but in accordance with my concept, I mechanically disperse the size. For example, rosin, wax, paraflin or similar sizing ingredients either singly or in combination, have not been dis persed without complicated chemical treatment. I propose by my present method to mix this mechanically m a fibrous mixture ,medium whereby to provide aeomplete mixture without including any extraneous or reactive concomitants.

To this end my present invention contemplates a method ofefl'ectin such a mixture and to illustrate this I will iscuss a methodical procedure by which such sizing may be accomplished.

To distribute a sizing such as rosin wax, or other sizing ingredients, ina pulp solution as ground. wood pulp or ground wood and chemical fibre pulp, or other fibrous pulp materials, or any of them in combination, I

effect first a mechanical mixture as heretofore suggested. The mechanical mixture of such a substance, as rosin, wax, paraffin or the like, in fibre presents some difiiculties of culiar nature.

I find that such mixtures can be most readily effected where the fibrous mixture medium is a dry bat or sheet, referably somewhat compacted. Such brous mixture medium may be wood fibre, a vegetable fibre, a chemical fibre as distinguished from an untreated wood fibre, or I may use any other fibre possessin the equivalent ualities.

, The size an fibre may be wor ed together was. mm Io. Mani.

by rolling or rubbin or similar operations, but in so doing the .P re shmlld be in a dry state to which the sizing ingredient should preferably be added in a melted condition. The mixing is carried on until the sizing ingredient has been completely mixed on the bre surface and preferably in amount of approximately 25% of the sizing ingredient to fibre. Where a bat or sheet is develo ed as a basis of mixture, the size will be abs: r ed by a progressive submersion by which any air in the bat is forced out. There is preferably in the ultimate product a phase of water dispersion so that by continued or su plemental treatment with water, the resu tant size is in sludge or fluid pulp form. The sizing is made from a hat or sheet. It is usually convenient to reduce it to a fluid consistency so that it can be more conveniently added to the pulp stock solution. In doing this it can simply be beaten up with water or with some of the pulp stock solution to which it is to be added.

All such stocks are preferably reduced to a fluid state and as best adapted to their production I provide a working basis at about 10% density as best for water disperslon.

In order to produce the highest perfection in my mechanically mixed size, I preferably carry its treatment to such a oint that the sizing material is incorporate into the fibre itself as distinguished from being merely on the surface. There seem to be three conditions of the fibre worked according to my process. These ma or may not represent states or stages, :1 though with some fibres and some sizings, the fibre doubtless passes through these successive conditions in successive stages of the process. The first condition to be noted is where the size is whollyon the surface of the fibre.

condition is apparently where the sizing has completely penetrated the fibre so as to amount to an im regnation. This bly mayrepresenta in ofthefibre ormterstices. may e nd on-the land of fibre used and the kin of, sizing and also to the degree of working or manipulation of the materials. complete 1mpregnation represents the most successful type of dispersion as it is absolutely free the mixture. The t first described while successful under mary conditions may have a slight tendency to gather in bunches or mam.

Such a sizing in ient comprising free we table fibre mec anically mixed fpreferab y with untreated size is capable 0 an mtimate and com lete mixture with ordinary ground wood u g or other pulp solutions to a produce a stoc cm which articles of most adtzintageous characteristics may be fabri- For example, such a sized stock can be run on a suction die machine in moulding articles such as plates or other containers in which waterroofness or grease-proofness is desired. nlike other sized stocks there is no clogging of the die perforations or screen interstices and the resultant articles, after drying at size fusing temperatures, are more perfectly sized and structured than any with ordinary sizing. In dryin the fusion of the flux seems more comp etc and efiicient than in any previously sized stock.

Without intending to limit m self, I oifer the further consideration. ere chemically treated fibre is used as the fibrous mi x mg medium, there seems possible a hydration of the fibre which aids materially in the mixing of the size. This may be only a partial or surface hydration, but it seems to as sist the attenuation of the size dispersion. The fibre should be preferabl dry and as free from moisture as possi Is. This is apart from any so-called h dration.

It will also be understood that where I use the term untreated size that I intend thereby to differentiate from emulsified or saponified sizings such as have been heretofore used. The size may be slightly saponified if desired and as before stated the size used may in itself be a blend or composition. The point is that the size used is in a state of substantial mechanical mixture in or on the fibre surface and is in an extremely. attenuated ingfibre throughout the pulpsolution to be sized to efiect a complete distribution and without danger of coagulation or flocculation. These and other reasonable inter retations of terms are to be understood as within the followin claims.

What I there ore claim and desire to secure by Letters Patent is:

1. That method of sizing an aqueous pulp from any tendency to flocculate or bunch in fib ly dryin suc state and capable of being carried by its mixfib solution, consist in into such solution amlxtureof ryfibres andanunemulsified sire.

2. That method of an aqueous pulp :olution, consistin inmaumixmg ilntosoluion a mixture fibres and an unemuliiifi' ed y dry 3. That method of prepa a sizing mixture, consisting in mec y mixing dry apulp solution,

consistin in first mixmg fibres and an untrea sizing, an in thereafter mixing 31a sized fibres into an aqueous pulp solu- 5. Thatmethod of sizing an aqueous ul solution, consisting in first distributin ah untreated sizing on a dry fibre sheet, in t ereafter disintegrating the sheet to efiect a complete mixture of the fibre with the sizing thereon to maintain the siz' in an attenuated state, and in finally mixing the sized fibres into the mucous pulp solution.

6. The meth of an aqueous pulp solution consisting iii first mechanically disan untreated sizing on a surface res and an untreated size. 4. That method of tribut' hydrate dry fibre to efi'ect an adherent attenuated mixture thereof, and in thereafter mixing the sized fibres into solution.

7. That step in the method of sizing an aqueous pulp solution, which consists in mixmg into the pulp solution a d mixture of unmodified size and hydrated bres.

8. The method of sizing an a ueous pulp solution which consists in first mixin fibres and a sizing ingredient in unheated condition, and in thereafter mixing said mixture with unsized fibres in the presence of water to form an aqueous pulp solution consisting of an unheated mixture of sized and unsized fibres.

9. The method of forming a greaseproofed molded article, which consists in first dry mixing fibres and a sizing ingredient in unheated condition, in thereafter mixmg said mixture with unsized fibres in the presence of water to form an ueous pulp solution consisting of an unhea mixture of sized and unsize fibres, die molding from such unheated solution anarticle of the desired size, sha and consistency and in finalmolded article at a tem rature su ciently high to effect the transfer of the size from the sized fibres to the unsized res.

In testimonyvwhereof I afiix my signature.

ALTER H. RANDALL.

the aqueous pulp