US1803648A - Method of sizing carbonate filled paper - Google Patents

Description

Patent ed May 5, 1931 j UNITED STATES PATENT OFFICE HAROLD ROBERT RAPTOR, OF LAWREIICE, SETTS ,ASSIGNOR TO RAFFOLD PROCESS CORPORATION, A CORPORATION 01 MASSACHUSETTS ployed in the METHOD OF SIZING CAR-BONATE FILLEDPAPER No Drawing.

This invention relates to the manufacture of paper and more particularly to an improved method of sizing carbonate filler. v q a A principal object of'this invention is to provide a method of sizing paper filled with carbonate filler wherein paraifin is employed as the sizing agent, the parafiin being emform'of a substantially nonbreakable emulsion, the disperse phase of such emulsion being concentrated by the mutual precipitation or flocculation of two suitable precipitating agents in the presence of the emulsion at the wet end of the paper machine,

Other objects and advantages of this-in- Vention will become apparent during the course of the following description.

In my copending application Serial No. 304,170, filed Sept. 5, 1928, I have described a process of sizing carbonate filled paper wherein a substantiallynonbreakable paraffin emulsion is employed as the sizing agent-,-

the disperse phase of such emulsionbeing concentrated by the mutual precipitation of two precipitating agents such as sodium resinate and alum at an earl stagein the paper making process, and w erein-the sizing effect'of the sizing agent which is wholly or in part-deteriorated b the action of the carbonate filler employe is restored by' the subsequent addition to the suitable sizing restoring agent, such as alum. I have now discovered that a certain satisfactory measure of success can be obtained by omitting the addition of one ofthe mutual precipitating agents 'suchas alum at an early stage of the process and adding it to the paper mix at the wet end of the paper machine.

In the preferred'practice of-my process I add to fibrous material in a beater, mixer, or similar device carbonate filler, a substantial- 1y s-nonbreakable paraflin emulsion and so- .3 dium ires1nate 1n a sufliclent amount as 1nd1-' 5:" cated below. Other material such as color-' fling matter-may be added to the mix if de- 5 sired. The mix: is then passed through the ,5 i"'f u's ual preliminary steps in the paper making :and a or subsequent to the point .wherethe mix is diluted prior to its. passage paper filled with paper mix of a Application filed September 5', was, Serial no. 304,173.

on to a web-forming device of a paper machine,

a'suitable amount of a mutual precipitating agentsuch as alum, preferably in solution, is'added to the mix, preferably con-,

tinuously. In other words, this material is added to the mix at the wet end of the paper machine. This results in :the concentration of the disperse phase of the parafiin emulsion and the afiixing of such disperse phase to the fibers whereb the pa er, but would produce a substantially unslze paper. Thus the precipitate produced by sodium resinate and alum does not in this case act as a sizing agent but as a concentrating. agcnt.- Of course I may, if I desire, use a greater quantity of sodium resinate, but it-is to be pointed out that it is possible to A secure satisfactory sizin by my .process where there is not enoug sodium resinate used to'impart sizing of itself.

' By the addition of one of the mutually precipitating materials, such as the alum, at the wet end of the paper machine, the alum is I after "the passage of the mix. through the usual felting and finishing steps,

thus aded at a point where there will be a minimum of intimacy and time of contact of the constituents of the mix, before the paper web is formed. It is necessary as indicated to add the alum at or subsequent to the point of dilution of the mix, as I have found that if it be added when the mix is in relatively concentrated condition and particularly when 'the relatively concentrated mix is subjected-to agitation as is normal-in stock chests, the sizing effect in the mix is very quickly deteriorated even to the point of complete destruction. The sizing effect even when the mix is in the diluted condition is gradually deteriorated, but is substantially u'naifected"within the time limits that the mix is maintained in the dilute state in the usual paper-making procedure. Moreover, althoughagitation in the dilute state hastens to a certain extent the dete rioration of the sizing effect, the speed of deterioration is not nearly so pronounced asr ments do not indicate that any substantially better sizing effect is obtained thereby, although the tendency to foam may be somewhat lessened, and such addition therefore can be considered the substantial equivalent of adding sodium resinate in the beater.

Similarly of course it is obvious that the substantially nonbreakable emulsion maybeadded at any point prior to web formation other than in the beater, even after the ad dition of the alum, and such addition-therefore can be considered the substantial equivalent of adding the substantially nonbreakable emulsion in the beater, providing only of course that the substantially non'breakable emulsion must be present at the time when the sodium resinate and alum mutually precipitate so that its disperse phase may be concentrated thereby as previously described herein. v The alum'solutionneed not be added directly to the fibrous mix, but can be added to the fresh water or white water, e. g. tray water, with which the mixis diluted. If the alum be added to the tray water, time interval should elapse before the so treated tray water is used for dilution Although substantially more foam is produced inthe herein described process than in the process referred to in my copendmg application, (except possibly in that-modification wherein sodium resinate would be added at the wet end of the paper machine after the alum addition), nevertheless the foam is altered in character by the alum before the mix is passed onto the web forming device, so that what foam is not held back in the rifllersorthe like is of such nature that it causes substantially no trouble during the formation of the web, and the paper produced by this process is of a satisfactory quality. Moreover inasmuch as the amount of alum used in the present process is less than that used in the process set forth in my copending application referred to above, the present process therefore results in a more economical operation.

The substantially nonbreakable paraffin emulsion herein described should not be confused with parafiin emulsions prepared by employing a saponaceous emulsifying agent.

only a brief Nor shouldthe emulsion be confused with emulsions made with an insoluble emulsify- 1ng agent such as colloidal clay, such for example as emulsions produoed from 'pitchy or bituminous materials such as tar or asphalt. These various types of emulsions re-' ferred to differ in many respects from my substantially nonbreakable paraflin emulsion and are not suitable for use in the practice of my process.

The paraflin emulsions which I have found to be substantially nonbreakable by any of the chemical or mechanical agencies ordinarily employed in paper making'in the con centrations or intensities at which they are normally used may be made in a variety of ways, for instance, with gums such as gum ghatti or gum arabic. While dextrin of itself does not appear to be suitable as an emulsifying' agent, particularly if the emulsion is to be stored for any appreciable time, it does however appear to be useful in connection with the gums mentioned above. As the gums are normally much more expensive than (lextrin, thedextrin may thus be used in conjunction with the gums to produce in general 'a lower cost emulsion. I have tested several formulae involving the use of gums and dextrin whichgive emulsions of essentially the nature desired, and which appear to work satisfactorily for the purpose. However, the one which I prefer to use in practice and which I have found to work Well-on a practical scale, is an emulsion made of paraffin with gum ghatti and dext'rin as emulsifying agents. In one such emulsion, for example, which proved satisfactory, I used by weight as follows:

15 parts parafiin, 1 part gum ghatti, 1 part dextrin, 83 parts Water.

As stated above so far as I have been able to discover by experiment, the'emulsions which I employ are not affected in anyway by any of the chemicals with which they come in contact at the concentrations at which they are used in the paper making process, nor are they'aifected by any of the mechanical agencies with which they come in contact at the intensities at which they are normally-employed in the paper making process.

The reason for this latter characteristic is probably that the particles in my emulsions are surrounded with a film which is one or more molecules in thickness and hence'entire- 1y of negligible thickness compared with any insoluble emulsifier film. Hence such films cannot be knocked oil or ruptured by ordinary mechanical means, as the thickness of this film is of entirely different order of magnitude (smaller) than are the clearances which ob --tain in the paper makingmachinery.

Of course it is not necessary that the emulsifier I use be water soluble in-the sense that sodium chloride, for instance, is soluble, as materials which are known in the art as bepable of having its disperse phase concen-' ing colloidally soluble, are also suitable. For

example gum ghatti which is suitable for my use may be considered to be in a measure col loidally soluble. With emulsifiers of the type I employ the condition of the layer surrounding the disperse phase .is such that by mechanical action in the paper making process,

. this layer is not disrupted, and therefore, the

emulsion remains substantially nonbreakable as heretofore indicated. It is to be understood that I do not confine myself to the materials indicated aboveas being suitable for my emulsion since now that the principle of the use of a substantially nonbreakable parafiin emulsion which is catrated has been established in the paper industry, doubtless other similar emulsions will v emulsion nor to definite proportions of emulbe evolved. N or'do I confine myself to the definite concentration of the paraffin in'the sifying agents to each other or to the parai'fimj as these may be variedin considerable degree without affecting the desirable qualities of the emulsion.

Emulsions of the character referred to may- Y be made ina variety of ways, as for example,

in a dispersion machine such as any of a number of colloid mills or homogenizers. A suitable way is to melt the paraflin, dissolve. the emulsifying-agent or agents in water, heat the emulsifying agent solution above the melting point of the parafiin and then feed the melted paraflin and the heated solution of emulsifying agents jointly to the emulsifying machine. I p

' In regard to the paraffin used, it 1s to be understood that either low or high melting point material can be employed. The" so-calledfully refined parafiin is entirely satisfactory sinceit does not impart objectionable color to white sheets. However, for purposes ofeconomy, it is often desirable to use a less pure material such for example as thematerial which is commonly known to theTtrade as semi-refinedparaifin scale, containing approximately 1-2 per cent of oil'and water as impurities, which material gives satisfactory results. Such material will perhaps in certain cases have varying melting points, but one particular sample used, for example, had a melting point of approx1mately 115 F.

(46 (3.). Other even more impureparafa fins may be 1 used, especially if the color (whiteness), requirements of the finished paper are not too exacting, or if papers, other than white, are to be In de.

As heretofore stated, in the preferred practice of my process I add at the wet end of the paper machine to'a mix containing fibrous material sbdium'resinate and a substantially nonbreakable parafiin emulsion of the char- :acter referred to, a material which will mutually precipitate or flocculate with the sodium resinatepresent in the IPIX. This; results in 'vantageonslyfied' in the' the concentration of the disperse phase of "j the parafiin emulsion whereby such disperse phase becomes attached to the fibers and does not filter 'oif therefrom during the passa e of the mix over the web-forming device 0% paper machine. The mutual precipitation or flocculation described serves, as stated, as a means for concentrating the disperse phase of the emulsion without breaking the emulsion,

the disperse phase in the: meantime being maintained in emulsified condition, and substantially nonbreakable by chemical or mechanical means; This concentration of the disperse phase appears toproduce a complex wh1ch expenments lndicate to be an lntermediate between a trueemulsion and a re-.

solved or broken emulsion. For example, the complex can be temporarily dispersed by mechanical means but not diluted in the true sense as in the case of true emulsions. However, the complex can in a sense be diluted by dissolving .the precipitate of the mutually flocculating agents therein and reconverting to atrue emulsion. Thus while it is clear that the complex is not a true emulsion it is on the other hand, not a resolved emulsion.

For example, the parafiin is not present in the concentrate as individual unitary deposited particles of paraflin, but rather in emulsified form, each particle being surrounded by a layer or film of emulsifying agent which prevents the individual particles from having contact not only. with other particles of paraflin, but also from having contact with either the alum-sodium resinate precipitate,

the.

or the fibres, or other constituents of the fibrous mix. .The existence of the parafiin able paraflin emulsion Calcium; carbonate magnesium hydroxide (carbonate er J M aterz'dl, added proportionately and contin- UKOUS'ZQ/ 0a dilution Pound- Another illustrative furnish is as follows:

Material added in the beater Fibrous furnish (e. g. approximately equal parts of 'sulphite, soda and old paper stocks) Rosin (added in the form of sodium resinate)I Parafiin (added in the form of substantially nonbreak- Pounds lie sulphite and soda Dulps) 17%)8 able paraifin emulsion) z 30 Broke" (containing calcium carbonate magnesium hydroxide (carbonate fil1er)) 170 Oaaium carbonate magnesium L HrBETEETCERBBTEE o p Alum a In the above formulae, the weightsof car'- bonate filler refer to the bone dry basis, the weights of all other ingredients being given on the air dry basis.

In either of thabove furnishes starch may be used. It may be conveniently added to the beater subsequent to the addition of the carbonate filler, or otherwise if desired. Suitable coloring matter may be added if desired.

The illustrative furnishes given above produce satisfactorily sized paper, and, as will'be apparent, the sizing can be increased 'or decreased by varying the relative quantities of the materials used in the above formulae. The resultant paper may be used for such purposes as those to which sized papers are normally put including that as a raw stock for further conversion as for example for coatmg.

In place of alum in the practice of my process I may employ with a measure of success an acid such as sulfuric acid (H SO an acid salt such as sodium bisulfate (NaIIsOior a salt of a trivalent metal, such as ferric iron, or the other salts of aluminum. Of the aluminum salts available I may use the chloride or the like, but I prefer to use ordinary alum. i

In place of sodium resinate I may use satisfactorily in the practice of my process other soaps, such as the oleat'es, or any partially or completely saponified material, such as saponified beeswax.

, 'Bythe term carbonate filler?-'as employed herein, is intended to be included calcium carbonate, of which lime mud from the causticizing process is one form; calcium carbonate magnesium basic carbonate employed in the paper disclosed, in m U. S. Patent No. 1,595,416; calcium carbonate magnesium hydroxide disclosed in my U. S. Patent No. 1,415,391; or other substantially water insoluble normal or basic carbonates of alkaline earth metals, (which expression is herein intended to includcmngnesium) ,or compounds,

double salts, or physically associated mixtures of these with one or more other acid soluble materials of a substantially'water insoluble nature. The term carbonatefiller is also intended to include fibrous material and/or other material such as paper coating constituents or the like containing one or more compounds of the character referred to, such as old papers or slmilar papers,

" broke, or the like.

By. ,the term Wet end of the paper machine is interidedto be includedthose instrugtrated paper mixis diluted, and7treated, conve'yed or fed up to the point of web-formation, such as the mixing box, regulating and proporti'oning devices, rifliers, troughs, screens, head boxes, inlets, and the like, including also instrumentalities used in the white water cycle.

When I employ the term paraffin herein, I mean parafiin wax, which 1s solid at ordinary or room temperature. I do not mean to restrict myself only to the paraflin hydrocarbons, but mean to include in this term all the hydrocarbons of -a waxy nature sub-- stantially unsaponifiable and inert to acidic and alkaline materials under ordinary conditions of temperature and pressure, whether derived from petroleum, shale, lignite, earth wax, or other natural or artificial sources.

I do not, however, means to include in this term material of a, pitchy nature, such as bitu: men or asphalt.

Where I use the term sodium resinate it is to be understood that I mean it to include any material produced by the action of alkali, generally in aqueous solution, on rosin, or on natural or synthetic resin acid or acids, regardless of the exact composition of the product, or the varying composition which different samples may possess.

When I use the word paper herein, I use it in the broad sense to include products of manufacture of all types and of all weights and thicknesses, which contain as an essential constituent a considerable amount of prepared fiberand which are capable of being produced on a Fourdrinier, cylinder, or other forming, felting, shaping or molding machine.

While I have described in detail the preferred embodiment of my invention, it is to be understood that the details of procedure, the proportionsof ingredients, and the arrangement of steps may be widely varied without departing from the spirit of the invention or the scope of the subjoined claims.

I claim:

1. The method of. manufacturing a sized paper filled with carbonate filler comprising adding to fibrous material a substantially nonbreakable paraffin emulsion and a substance which will react with a second substance subsequently to be added to form a precipitate, said reaction serving to concentrate the disperse phase of said parafiin emulsion but not to break said emulsion, adding carbonate filler, thereafter adding said second precipitating substance under conditions favoring the minimizing of the time of contact of the constituents of the mix, and thereafter making paper therefrom.

2. The method of manufacturing a sized paper filled with carbonate filler comprising adding to fibrous material a substantially nonbreakable paraffin, emulsion and a substance capable of reacting with a second substance subsequently to be added to form a precipitate upon the fibrous material, said reaction serving to concentrate in association with saidpreclpitate thedisperse phase of said paraflin emulsion but not to break said emulsion, said precipitate being substantially incapable of having the paraflin associated therewith released from emulsified condition by mechanical means, adding carbonate filler, thereafter adding said secondprecipitating substance under conditions favorin the minimizing of the time of contact of the constituents of the mix, and thereafter making paper therefrom.

3. The method of manufacturing a sized paper filled with carbonate filler comprising adding to fibrous material asubstantially nonbreakable paraffin emulsion and a substance which will react with a salt of a trivalent metal to form a precipitate, said reaction serving to concentrate the disperse phase of said paraffin emulsion but not to breaksaid emulsion, adding carbonate filler, thereafter adding said salt of a trivalent metal under conditions favorin the minimizing ofthe time of contact 0 the constituents of the mix, and thereafter making paper therefrom. 4. The method of manufacturing a sized piper filled with carbonate filler comprising a ing to fibrous material. a substantially nonbreakable paraflin' emulsion and a substance which will react with a salt of aluminum to form a precipitate, said reaction serving to concentrate the disperse phase of saidparaflin emulsion but not to break said emulsion, adding carbonate filler, thereafter adding'saidsalt of aluminum under conditions favorin the minimizing of the time of contact of t e constituents of the mix, and thereafter making paper therefrom.

- 40 5. The method of manufacturing a sized paper filled with 'CarbonateTfilier comprising ad ing to fibrous material a" substantially nonbreakable 'paraifin emulsion and a substance which will react'with alum to' form a precipitate, said reaction servin to concentrate the disperse phase, of sai parafiin emulsion but not to break said emulsion, add- -ing carbonate filler, thereafter adding said alum under conditions favoring the minimize 0 ing of the time of contact of the constituents of {the mix, and thereafter 'makin'gi paper therefrom. v

6. The method of manufacturinga sized paper filled with carbonate filler comprising s adding to fibrous material {a substantially I nonbreakable parafiin emulsion and a substance which will react with a second sub: stance subsequently to be added to form a precipitate,.said reaction serving to concentrate 0 the disperse phase of said paraflin emulsion but not to break said emulsion, adding carbonate filler, thereafter adding said second precipitating substance under conditions favoring the minimizing of the t me and 1ntimacypf contact of the constituents of; the

mix, and thereafter making paper therefrom. 7. The method of manufacturing a sized paper'filled with carbonate fillerl comprising adding to fibrous material a substantially nonbreakable paraflin emulsion and a substance which will react with a second substance subsequently-to be added to. form a precipitate, said reaction serving to concentrate the disperse phase of said parafiin emulsion but not to break said emulsion, adding carbonate filler, thereafter adding said second precipitating substance at the wet end of the paper machine, and thereafter makingv paper therefrom.v

v 8. The method of manufacturing a sized paper filled with carbonate filler comprising adding .to' fibrous material a substantiallynonbreakable paraffin emulsion and a substance which will react with a second substance subsequently to be added to form a precipitate, said reaction serving to concentrate the disperse phase of said parafiin emulsion but not to break said emulsion, adding carbonate filler, thereafter adding said sec- 0nd precipitating substance at a point in the process at which the mix is diluted preparatory to use on a web-formin device, and thereafter making paper there rom.

9. The method of manufacturing'a sized paper filled with carbonate filler comprising ing a precipitant for said saponified mate-' rial at the wet end of ,the paper machine, and

thereafter making paper therefrom.

11. The method of manufacturing a sized paper filled with carbonate filler comprising mixing with fibrous material a substantially nonbreakable paraflin emulsion,

ingalum at the wet end ofthe paper machine,

thereafter making paper therefrom 12. The' method'of manufacturing a sized paper filled with carbonate filler comprising mixing with fibrous material a substantially nonbreakable paralfin' emulsion, soap, and carbonate filler, thereafter adding alum at the wet after making paper therefrom.

passing the mixsa' onifiedmaterial, and carbonate filler',-thereaf "r addend of the paper machine, andthere-- 13. The method of manufacturing a sized paper filled with carbonate 'fill'er comprising mixing with fibrous material a substantially nonbreakable paraflin emulsiomsodium resinate, and carbonate filler, thereafter adding alum at the wet end of the paper machine, and thereafter making paper therefrom.

14. The method of manufacturing a sized paper filled with carbonate filler comprising mixing with fibrous material a substantially nonbreakable paraflin emulsion, sodium resinate, and carbonate filler, thereafter adding a precipitant for said sodium resinate at the wet end (if the paper machine, and thereafter making paper therefrom.

15. The method .of manufacturing sized paper filled with carbonate filler comprising mixing with fibrous-material a substantially nonbreakable parafiin emulsion, sodium resinate in an amount insufficient of itself to impart a substantial degree of sizing to the *paper, and carbonate filler, thereafter adding alum at the wet end of the paper ma- Ichine, and thereafter making paper-therefromr 16; The method of manufacturing'a slzed' paper filled with carbonate filler comprising mixing with fibrous material a parafiin emulsion made with gum ghatti as emulsifying agent, sodium resinate, and carbonate filler, thereafter adding alum at the wet end of the papa: machine, and thereafter making paper therefrom. v

17. The method of manufacturing a sized paper filled with carbonate filler comprising mixing with fibrous material a paraffin emulsion made with gum ghatti and dextrin as emulsifying agents, sodium resinate, and carbonate filler, thereafter adding alum at'the wet end of the paper machine, and thereafter makin paper therefrom. i

18. n a method of manufacturing a sized paper filled with carbonate filler, the step of adding at the wet end of the paper machine a precipitant to a paper mix containing fibrous material, carbonate filler, a substantially nonbreakabl e p'araflin emulsion and v saponified material.

' Y of adding at the wetendof the paper manonbreakable 19. In a method of: manufacturing a sized paper filled with carbonate filler, the. step chine, asalt of a trivalent metal to a paper mix containing fibrous material, carbonate filler, a substantially nonbreakable paraflin emulsion and saponified material.

20. In a method of manufacturing a sized paperfilled with carbonate filler, the-step of'adding at the wet end of the paper machine a salt of aluminun'rto a paper mix containing fibrous material, carbonate filler, a substantially rionbreakable paraflin emulsion and sa onified material.

inate.

24. That step in the method of manufacpaper filled with carbonate filler, the ste of adding at the wet end of the paper mac ine alum to a paper mix containing fibrous material, carbonate filler, a substantially nonbreakable paraffin emulsion and soap.

. 23. In a method of manufacturing a sized paper filled with carbonate filler, the step. of adding at the wet end of the paper machine alum to a paper mix containing fibrous material, carbonate filler, a substantially nonbreakable paralfin emulsion and sodium resturing a sized paper filled with carbonate filler in which a parafiin emulsion is employed, comprising the addition of aprecipitatin substance'to the paper mix at the wet end 0 the paper machine.

25. That step in the method of manufac turing a sized paper filled with carbonate.

filler in which a paraflin emulsion is employed, comprising the addition of acidic material to the paper mix at the wet end of i the paper machine.

26. hat step in the method of manufacturing a sized paper filled with carbonate filler in which aparaflin emulsion is employed, comprising the addition of metallic salt to the paper mix at the wet-end'of the.

21. n a'method of manufacturing a sized paper filled with carbonate filler, the step of adding at the wet end of the paper machine alum; to a paper mix containing fibrous material, carbonate filler, a substantially fied material.

22. In a method of manufacturing a.

paraflin emulsion and saponiature. I