US1803652A

US1803652A - Method of sizing carbonate filled paper

Info

Publication number: US1803652A
Application number: US304177A
Authority: US
Inventors: Rafton Harold Robert
Original assignee: Raffold Process Corp
Current assignee: Raffold Process Corp
Priority date: 1928-09-05
Filing date: 1928-09-05
Publication date: 1931-05-05
Anticipated expiration: 1948-05-05

Description

Patented May 5, 1931 UNITED STATES PATENT OFFICE HAROLD ROBERT RAITON, OF LAWRENCE, MASSACHUSETTS, ASSIGNOR TO RAFFOLID PROCESS CORPORATION, CORPORATION OF MASSACHUSETTS METHOD OF SIZING CARBONATE FILLED PAPER No Drawing.

This invention relates to a method of sizing paper and more particularly to a method of sizing paper filled with carbonate filler.

The principal object of this invention is to provide a method of sizing paper filled with carbonate filler wherein a paralfin emulsion made with a substantially water insoluble type emulsifying agent is added to a paper mix in the beater together with a potential fibre associating agent, and a precipitant for such potential fibre associating agent is added to the resulting mix at the wet end of the paper machine.

My invention is directed to sized paper such as is used for printing purposes, for coating raw stock, or the like. It is not di rected to water-proof products such as prepared roofing or the like, nor to paraifined papers which normally have a paraflin finish,

which makes them substantially waterproof and usually translucent or transparent and unsuited for the uses to which I wish to put my sized paper.

Other objects and advantages of this invention will become apparent from the course of the following description.

In my copending application Serial Number 304,176, filed Sept. 5,, 1928, I have described a method of sizing paper filled with carbonate filler wherein there is added to fibrous material in a heater a paraflin emulsion made with a substantially water insoluble type emulsifying agent, sodium resinate and alum and carbonate filler, and a restoring agent such as alum is added to the resulting mix at the wet end of the paper machine. However, I have discovered that a certain measure of success may be obtained in sizing certain grades of paper filled with carbonate filler by adding to the fibrous material and carbonate filler in the beater a paraflin emulsi on of the character referred to together with a potential fibre associating agent, preferably sodium resinate, and adding a precipitating agent such as alum to the resulting mix at the wet end of the paper machine.

In the preferred practice of my process I add in a heater or the like to paper stock containing fibrous material and a carbonate filler,

0 a suitable amount of a paraflin emulsion made Application filed September 5, 1928. Serial No. 304,177.

with a substantially water insoluble type emulsifying agent. In preparing such an emulsion I may use as an emulsifying agent a substantially water insoluble material such as clay or even carbonate filler itself. The method of making such emulsions is well known and this method ordinarily comprises heating parafi'in above its melting point and adding the melted paraflin with vigorous agitation to a suspension of the substantially water insoluble material in water which is pref erably maintained at approximately the same temperature as that of the melted paraffin. Vigorous agitation is meanwhile carried on and is continued while the emulsion is cooling. I then add to the fibrous material and carbonate filler contained in a heater, mixer or similar device the parafiin emulsion and a potential fibre associating agent such as sodium resinate, which serves to associate the emulsion with the fibre when a suitable precipitating agent therefor is subsequently added at or subsequent to the dilution of the paper mix prior to its delivery on to a webforming device. The amount of sodium resinate I may use is that amount which by itself when precipitated with alum, in accordance with my copending application Serial No. 304,172, filed Sept. 5, 1928, would not be suflicient to size the paper, but would produce a substantially unsized paper. Thus the precipitate produced by sodium resinate and alum does not in this case act as a sizing agent but as a fibre associating agent. Of course, I may, if I desire, use a greater quantity of sodium resinate, but it is to be pointed I the fibres and the finished paper produced is satisfactorily sized.

Were no alum or equivalent material added at the wet end of the paper machine to the paper mix containing fibrous material, carbonate filler, parafiin emulsion of the type referred to, and sodium resinate, the potential fibre associating agent would not be developed into a fibre associating agent. In this case, of course, in so far as associating the emulsion with the fibre were concerned, it would be the same as if no sodium resinate were present and the paperfmix contained only fibrous material, carbonate filler, and the paraffin emulsion of the type referred to. In such case, of course, only-such parts of the paraffin emulsion as would be mechanically filtered out by the fibre would be retained thereon and the paper produced would not be satisfactorily sized, except possibly at the expense of a greatly increased quantity of paraffin, which would be undesirable both because of certain mechanical instability as indicated below, as well as because of prohibitive cost.

By the addition of the alum at the wet end of the paper machine, the alum is thus added 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 fibre associating effect in the. mix is very quickly deteriorated even to the point of complete destruction. The fi-b-re associating effect even when the mix is in the diluted condition is gradually deteriorated, but is substantially unaffected within the time limits that the mix is maintained in the dilutestate in the usual paper making procedure. Moreover, although agitation in the dilute state hastens to a certain extent the deterioration of the fibre associating effect, the speed of deterioration is not nearly so pronounced" as in the concentrated condition, and from a practical standpoint I have found that the agitation to which the diluted mix is subjected prior to delivery onto the web-forming device does not deteriorate the fibre associating effect to a substantial degree.

Of course the potential fibre associating agent, such as the sodium resinate, may be added at any point prior to web formation other than in the beater, even after the addition of the alum, but experiments do not indicate that any substantially better fibre associating effect is obtained thereby, al-' though 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.

The alum solution need 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 mix is diluted. If the alum be added to the tray water, only a brief time interval should elapse before the so treated tray water is used for dilution.

Although substantially more foam is'produced in the herein described process than in the process referred to in my copending application Serial No. 304,176, filed Sept 5, 1928, (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 rifilers or the like is of such nature that it causes this process is of a satisfactory quality.

Moreover, inasmuch as theamount of alum used in the present process is less than that used in the process set forth in my copending application referred to just above, the present process therefore results in a more economical operation.

Although, clay is my preferred substantially water insoluble emulsifying agent, I may use also other substantially water 1nsoluble emulsifying agents which do not exist as such originally, such for example, as any agent formed from two mutually precipitating materials which is adapted to yield a substantially water insoluble coating around the individual particles of paraffin. The method of making such emulsions is well known. Such an emulsion may be completely made prior to addition to the fibrous pulp, or it may be formed in the pulp by dispersing the paraflin originall in a soluble material which will prevent 1ts agglomeration in the pulp mass, and then subsequently forming a substantially water insoluble coating on the dispersed paraffin particles by adding to the pulp mass and dispersed paraifin a material which will mutually precipitate the original dispersing material into a substantially water insoluble layer or film around the dispersed paraffin particles.

Papers made in accordance with my invention are well sized but because of the relatively large size of the particles in com arison with the nonbreakable parafiin emu ion described in my copending applications Serial No. 304,170, filed Sept. 5, 1928, and Serial No. 304,17 3, filed Se t. 5, 1928, the sizing is not quite so well istributed through the paper. Thus, it is usually desirable to use somewhat more paraflin than in the copending applications referred to just above. Moreover, in order to secure uniform distributage for preparing certain grades of paper where the requirements are not so exacting.-

The emulsion herein employed, although reasonably resistant to chemical agencies, especially if the substantially waterinsoluble emulsifying agent employed be also substantially acid insoluble, has certain defects from a mechanical standpoint which should be taken into account in its use. The chief difliculty is'that this emulsion has a tendencyto be mechanically unstable, and when sub ected ,to pressure as by the action of the beater, some of the particles may have their protective coating of clay removed, and thus be released from emulsified condition with consequent release of articles of free paraflin in the stock, which have a tendency to agglomerate and cause trouble in the paper making process. For this reason it is desirable to beat the fibre prior to the addition of the emulsion and then raise the beater roll just prior to adding the emulsion, using-the roll merely for mixing rather than for beating purposes thereafter in order to prevent the breakdown of the emulsion by the beater.

The action of the fibre associating agent does not seem to have a noticeable breaking effect on the emulsion itself, and thus the paraffin is not thereby directly released from emulsion, but the same defect regarding the action of mechanical agencies on the emulsion as set forth above seems to be inherent in the emulsion whether alone, or when associated with the fibre associating agent.

, An illustrative furnish which may advantageously be used in practicing my invention is as follows:

Materials added in the beater Pounds Fibrous furnish (e. g. sulphlte and sgda pulps) 1700 Rosin (added in the form of sodium resmate) 10 Paraflln (added in the form .of a substantially water insoluble emulsifier type of emulsion) Calfiiun; carbonate magnesium hydroxide (carbonate 300 Material added proportionately and continuouslg on dilution Pounds Alum (ordinary Al (S0 .18 H O 65 Anotherillustr'ative furnish is as follows:

Mdtem'als added in the beater Pounds Fibrous furnish (e. g. approximately equal parts of 1 -sulph1te, soda and 01d paper stocks) 1800 Rosin (added in the form of sodium resinate) 10 Paraflln (added in the form of a substantially water insoluble emulsifier type of emulsion), v Calcium carbonate magnesium hydroxide (carbonate. -fl11er) 200 Mdte zal. added proportionatety and corttnw ously. on ditutz'on Pounds Alum (ordinary A1,(so.),.1sH,o 65

In the above formulae the weights of carbonate filler refer to bone dry basis, the weights of all other ingredients being'given on the air dry basis. a

In regard to the araffin used, it is to be understood that eit er low or high melting point material can be employed. The socalled fully refined paraffin is entirely satis- .factory since it does not impart objectionable color to white sheets. However, for purposes of economy, it is often desirable to use a less pure material such for example as the material which is commonly known to the trade as semi-refined paraflin scale. containing approximately 1-2 per cent. of oil and water as impurities, which material gives satisfacg tory results.

Such material will perhaps in-certain cases have varyin melting points, but one particular sam e used, for example, had a melting point 0 approximately 115 F. (46 C.). Other even more impure araflin may be used, especially if the color whiteness) requirements of the finished paper are not too exacting, or if papers, other than white, are to be made.

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 In place of sodium resina-te I may use satis- 5 factorily in the practice of my process other soaps, such as the oleates, or any partially or completely saponified material, such as saponified beeswax.

By the term carbonate filler as employed 1,10

' 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 my U. S. Patent No.

0 1,595,416; calcium carbonate magnesium hydrox'ide 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 include magnesium) or compounds,

5 stituents or the like containing one or more compounds of the character referred to, such 18 as old papers or similar papers, broke, or the like.

By the term wet end of the paper machine is intended to be included those instrumentalities employed in paper manufacture by which and/or in which a relatively concentrated paper mix is diluted, and treated, conveyed or fed up to the point of web-formation, such as the mixing box, regulating and proportioning devices, rifiiers, 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 paraffin wax, which is solid at ordinary or room temperature. I do not mean to restrict myself only to the paraffin hydrocarbons, but mean to include in this term all the hydrocarbons of a waxy nature substantially 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, mean to include in this term material of a pitchy nature, such as bitumen 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.

lVhen 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 fibre and 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 proportions of 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 sizing paper filled with carbonate filler comprismg mixing with fibrous material carbonate filler, a paraffin emulsion made with a substantially water insoluble type emulsifying agent, and a potential fibre associating agent, and thereafter adding to the resulting mix a precipitant for said potential fibre associating agent 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 sizing paper filled with carbonate filler comprising mixing with fibrous material carbonate filler, a paraffin emulsion made with a substantially water insoluble type emulsifying agent, and a otential fibre associating agent, and therea er adding to the resulting mix a precipitant for said potential fibre associating agent under conditions favoring the minimizing of the intimacy and time of contact of the constituents of the mix, and thereafter making paper therefrom;

3. The method of sizing paper filled with carbonate filler comprising mixing in the beater with fibrous material carbonate filler, a paraflin emulsion made with a substantially water insoluble type emulsifying agent, and a potential fibre associating agent, and thereafter adding to the resulting mix a precipitant for said potential fibre associating agent under conditions favoring the minimizing of the intimacy and time of contact of the constituents of the mix, and thereafter ma ing paper therefrom.

4. The method of sizing paper filled with carbonate filler comprising mixing with fibrous material carbonate filler, a paraffin emulsion made with a substantially water insoluble type emulsifying agent, and a potential fibre associating agent in an amount insufficient of itself to impart substantial sizing to the paper, and thereafter addin to the resulting mix a precipitant for sai potential fibre associating agent under conditions favoring the minimizing of the time of contact of the constituents of the mix and thereafter making paper therefrom.

5. The method of sizing paper filled with carbonate filler comprising mixing with fibrous material carbonate filler, a paraffin emulsion made with a substantially water insoluble type emulsifying agent, and a potential fibre associating agent, and thereafter adding to the resulting mix a precipitant for said potential fibre associating agent at the wet end of the paper machine.

6. The method ofsizing paper filled with carbonate filler comprising mixing with fibrous material carbonate filler, a paraffin emulsion made with a substantially water insoluble type emulsifying agent, and a potential fibre associating agent in an amount insufficient of itself to impart substantial sizing to the paper, and thereafter adding to the resulting mix a precipitant for said potential fibre associating agent at the Wet end of the paper machine.

7. The method of sizing paper filled with carbonate filler comprising mixing with fibrous material carbonate filler, a paraffin emulsion made with a substantially water insoluble type emulsifying agent, and a potential fibre associating agent comprising saponified material, and thereafter adding to the resulting mix a precipitant for said saponified material at the wet end of the paper machine.

8. The method of sizing paper'filled with carbonate filler comprising mixing with fibrous material carbonate filler, a paraffin emulsion made with .a substantially water insoluble type emulsifying agent, and a potential fibre associating agent comprising soap, 'and thereafter adding to the resulting carbonate-filler comprising mixing with fibrous material carbonate filler, a paraflin emulsion made with a substantially water insoluble type emulsifying agent, and a potential fiber associating agent, and thereafter adding to the resulting mix a salt of a trivalent metalat the wet end of the paper machine.

11. The method of sizing paper filled with carbonate filler comprising mixing with fi-v brous material carbonate filler, a paraflin emulsion made with a substantially water insoluble type emulsifying agent, and a potential fiber associatin agent, and thereafter adding to the resulting mix asalt of aluminum at the wet endv of the paper machine. 12. The method of sizing paper filled with carbonate filler comprising mixing with fibrous material carbonate filler, a parafiin emulsion made with a substantially water insoluble type emulsifying agent, and a potential fiber associatin agent, and thereafter adding to-the resu ting mix alum at the wet end of the paper machine.

13. The method of sizing paper filled with carbonate filler comprising mixing 'with fibrous material-carbonate .filler, a paraifin emulsion made with a substantially water insoluble type emulsifying agent, and sodium resinate, and thereafter adding alum to the resulting mix at the wet end of the paper machine.

14. The method of sizing paper filled with carbonate filler comprising mixing with fibrous material carbonate filler, a -paraflin emulsion made with a substantially water insoluble type emulsifying agent, and sodium resinate in an amount insuflicient of itself to impart substantial sizing to the paper, and thereafter adding alum to the resulting mix at the wet end of the paper machine.

, 15. In a method of the character. described, the step of adding a precipitant at the wet end of the paper machine to a paper mix containing fibrous material, carbonate filler,

' a parafiin emulsion made with a substantially water insoluble type emulsifying agent, and a potential fibre associating agent.

16. In a method of the character described, the step of addin a precipitant at the wet end of the paper maciine to a paper mix containing fibrousmaterial,carbonate filler, a parafiin emulsion made with a substantially water insoluble type emulsifying agent, and a potential fibre associating agent in an amount insuificient of itself to impart substantial sizing to the paper.

17. In a method of the character described, the step of adding alum at the wet end of the paper machine to a aper mix containing fi brous material, carEonate filler, a paraflin emulsion made with a substantially water insoluble type emulsifying agent, and a potential fibre associating agent.

18. In a method of the character described, the step of adding a precipitant at the wet end of the paper machine to a paper mix containing fibrous material, carbonate filler, a

parafiin emulsion made with a substantially water insoluble type emulsifying agent, and saponified material.

19. In a method of the character described, the step of adding alum at the wet end of the paper machine to a paper mix containing fibrous material, carbonate filler, a paraffin emulsion made with a substantially water insoluble type emulsifying a ent, and sodium resinate in an amount insu cient' of itself to impart substantial sizing to the paper.

In testimony whereof I affix my signature. I HAROLD ROBERT RAFTON.