US1976744A - Paper manufacture - Google Patents

Description

Patented Oct. .16, 1934 UNITED STATES- PATENT OFFICE PAPER MANUFACTURE Harold Robert Barton, Andover, Mass assignor to Rafl'old Process Corporation, a corporation of Massachusetts No Drawing Application November 29, 1932, Serial No. 644,999

2s maime- (01. 92-21) no deteriorated sizing.

A further object is to improve the sizing of paper filled with alkaline filler made from a fibrous mix containing sizing, or undeveloped sizing.

A further object is to manufacture paper of imis proved sizing quality and filled with alkaline filler from a fibrous mix containing alkaline filler, which alkaline filler hasa tendency in certain cases to deteriorate or destroy the sizing on the driers of a paper machine.

Other objects and advantages of my invention will become apparent during the course of the following description.

' In my copending application Serial No. 501,674, filed December 11, 1930,'now Patent No. 1,922,325, granted August 15, 1933, I disclose a method of manufacturing sized paper filled with alkaline filler by the application of size and size precipitant to a paper web containing alkaline filler. Alternatively, the precipitant may be applied to the paper mix and the size to the web, or the size to the paper mix and the precipitant to the web, or precipitated sizing may be applied to the web. The claims ,in that application cover the practices disclosed, certain of the claims reading broadly to the application to the paper web of a size precipitant such as acidic material, for example alum; in a, process wherein a sizing agent is employed and wherein there is produced by the action of the precipitant applied to the web a substantially water insoluble substance capable of imparting sizing efiect to said web. It is also disclosed in said'application that the procedure employed therein may be used to impart additional sizing to a web containing alkaline filler already sized by other methods, such for example, as those methods disclosed in my then ccpending applications Serial Nos. 304,168 and 304,172, both filed September 5, 1928, and now tured into Patents Nos. 1,803,643 and 1,803,647, both issued May 5, 1931. Briefly, these two patents disclose respectively a method of employing size suchas rosin size to size paper containing ae filler, in" which method the fibrous mix containing rosin size which has been precipitated as with alum in the beater is treated with a sizing restoring agent just prior to formation of thepaper web; and a method employing size such as rosin size to size paper filled with alkaline filler, wherein the fibrous mix is treated with a size precipitant just prior to formation of the paper web.

The procedures shown in the above patents entail the addition either of a restoring agent or precipitant under conditions favoring the mini- I mizing of the time and/or intimacy of contact of the constituents of the mix, and thereby overcome or avoid the deterioration ordinarily taking place when sizing such as a size precipitate, for example, a rosin size precipitate, comes in contact with alkaline filler such as in the beater.

I have now devised a process which is in some of its aspects a modification of the general process covered broadly by certain of the claims of my copending application first above mentioned.

This process may be described briefiy as that of producing, restoring, preserving and/or improving sizing in a paper web containing alkaline filler by the application of a suitable sizing aifecting agent to the web, said web already containing either destroyed sizing, deteriorated sizing, undeveloped or underdeveloped sizing, or substantially undeteriorated sizing. This is accomplished without the application of additional sizing agent to the web, the sizing aifectinguagent applied to the web not being a sizing agent, but rather one which may act in conjunction with or upon a sizing agent or sizing.

However, in my invention the sizing afiecting agent does not act with or upon a soluble or emulsified sizing agent precipitable but theretofore unprecipitated, but rather with or upon a sizing agent or sizing which is either unprecipitable or which is added in precipitated form or which has already been precipitated, or which having been once precipitated or flocculated is now in a form such as either does not impart any sizing at all or not complete sizing, or would sufier deterioration in the absence of said sizing aiiecting agent, "in either of these alternatives the sizing agent or sizing being already in the mix prior to web formation.

In many of theOsizing. procedures used'with papers filled with alkaline filler, it has been ob served that somewhat more sizing agent may be required than in papers filled with non-alkaline filler. I believe that this, in certain cases, may be due to the fact that the sizing, although satisfactory when the min is delivered to the webiorming device, is somewhat deteriorated in the wet web by contact with the alkaline filler. This Hill deterioration probably takes place only to'a limited extent, if at all, at room temperature, (i. -e. in the web at any time before the driers are reached), but it is probably substantially accelerated on the driers by the temperatures employed in drying. The application of the present invention substantially prevents such deterioration of the sizing by the alkaline filler and thus permits substantially the full development of the sizing. This, as will be apparent, results in certain cases in considerable economy in sizing agent.

Several illustrative instances in which my invention may be practiced are given below, but of course it will be understood that these instances are not to be taken as limiting, because as will be apparent to one skilled in the art, my invention is capable of broad application.

(1) A mix made with fibrous material, alkaline filler, size such as rosin size, and alum in the concentrated stage of the papermaking process, such as in the beater, will normally have its sizing efiect greatly deteriorated if not completely de stroyed by the time the mix is ready for delivery to the web-forming device, because of the deleterious action of alkaline filler on the size precipitate and also on any excess alum which may be added to the mix. If such mix is run off on a paper machine the resulting paper will be substantially unsized or will have "only a relatively minor degree of sizing. By applying to a paper web so made a suitable sizing affecting agent, the destroyed or deteriorated sizing present in the web functions as potential sizing which is made active, or converted into effective sizing, by said closure of my Patent No. 1,803,647, e. g. by mixing fibre with size and precipitating said size just prior to web formation, the paper will be well sized; but by applying to a paper web so produced a suitable sizing affecting agent, the sizing of the sheet is improved.

(4) In my Patent No. 1,803,642, issued May 5, 1931, I disclose a method for the manufacture of sized paper filled with alkaline filler, by adding the filler to previously sized paper mix just prior to web formation. By applying a suitable sizing affecting agent to a paper web so produced, the sizing of the sheet is improved.

(5) In my copending application Serial No. 533,571, filed April 28, 1931, I disclose a temporarily protected alkaline filler, and in my Patent No. 1,879,483,'issued September 27, 1932, I disclose an alkaline filler with a pH value substantially stabilized by the use of an acidic ma- I terial such as alum. The use of these fll 's in sized paper, while having less deleterious effect on the sizing than untreated alkaline filler, nevertheless is accompanied in some instances by some 1 deterioration of the sizing effect of the paper, and

- when mixes containing such flllersare run off on the paper machine the application of a sizing af- 1' ecting agent to the paper web results in improved sizing effect being obtained from suchmixes.

(6) In my Patent No. 1,819,441, issued August 18, 1931, I disclose the fact that an alkaline filler such as a carbonate when treated with an emulsion of material such as paraflin which is substantially unaffected by alkaline filler, will form a complex, which may be considered as a protected alkaline filler. When such a filler is employed in the manufacture of sized paper, in which if desired sizing agents in addition to parafiin, such as rosin size and the like, may be used, a satisfactorily sized paper is produced, but I have found that in some instances a certain deterioration in sizing eifect results and in such cases by the application of a sizing affecting agent to the web, the sizing effect of the sizing in the sheet may be enhanced. This is even true in some cases where a restoring agent is additionally employed at the dilute stage.

(7) It has been proposed to treat alkaline filler with an emulsion of a fatty acid in order to obtain on the particles of the filler a superficial coating of a reaction product of the particles and the said fatty acid radicle, and then to employ this filer in the manufacture of sized paper employing rosin size as the sizing agent. When this practice has hitherto been attempted, it has been found that the paper made therewith is not thoroughly amenable to steam drying which makes the process impractical for use from an industrial standpoint, as the ordinary types of papers made on a commercial scale are for the most part dried completely on drying cylinders heated by steam, or, in certain grades of limited production such as in writing paper, at least partially so. However, by the employment of my process, this former proposal, infeasible of application commercially in the form proposed, now becomes a possible commercial procedure as by the application of a sizing affecting agent to a paper web containing said treated alkaline filler and sizing and/or deteriorated or destroyed or the like sizing, the sizing is maintained or preserved and/or developed and a well sized sheet results.

(8) As described in my Patent No. 1,803,643, in some instances, certain precipitants, e. g. sodium bisulphate, may be used with sizing agents in a paper mix containing alkaline filler, which precipitants while they convert the sizing agent into an insoluble form, nevetheless convert it into a form which may produce a lesser sizing effect than does alum; or in some cases certain precipitants produce substantially no sizing effect at all. Such precipitants prevent to a substantial degree the physical loss' of the soluble or emulsified sizing agent in the eflluent waters of the papermaking process, but as stated above they may impart either no, or only relatively poor, sizing effect to the resultant paper, that is they produce undeveloped or underdeveloped sizing. Examples of precipitants other than sodium bisulphate which produce such inferior effects are,

in certain instances, calcium compounds for ex- (9) In certain cases in alkaline filler fibrous 'mixes a non-acid compound of aluminum, such assodium aluminate, may be employed in conjunction with size such as rosin size. Alum may be additionally employed either in the concentrated and/or dilute stage of the papermaking process. Such mixes may at certain times and under some conditions, especially if no, or only insufficient, alum be used, produce a sheet with substantially no sizing effect or with inferior sizing effect. By the application of a sizing affecting agent to paper webs made from such mixm, satisfactorily sized papers result.

' (10) In various of my prior patents (e. g.Nos. 1,803,645 and 1,803,651), I disclose processes of using emulsions of substantially water insoluble sizing agents such as paraflin, wherein such emulsions may be associated with the fibre, for example by mutually precipitating flbre associating agents. In such cases, the application of a sizing affecting agent to the paper web. in certain instances, enhances the sizing eflect. Also, if there be a deficiency of fibre associating agent in the mix, or if such agents be deteriorated, or even completely lacking, fibrous webs formed from such mixes will have their sizing materially improved by the application of sizing affecting agent thereto in accordance with the present invention.

The sizing aflecting agent which I employ for the restoration, preservation, improvement or the like of the sizing in the paper web already containing alkaline filler and either undeveloped, underdeveloped, destroyed or deteriorated sizing or sizing capable of preservation or enhancement,

or the like, may be either gaseous, liquid or solid. It is usually of such a nature that, when caused to contact with a solution of rosin size, it .will precipitate such size. Forinstance acidic material in general may function, such for example as acetic acid or other organic or mineral acid as sulphuric or phosphoric acid, or acid salts such as sodium bisulphate. The acids may conveniently be applied to the web in liquid form, preferably in aqueous solution, but it is also possible to apply at least certain of them such as formic, acetic, or hydrochloric acid in gaseous form; and also to apply acids or acid anhydrides which occur in gaseous form at temperatures which will not substantially inJure cellulose fibre. Thus, for example,carbon dioxide or sulphur dioxide may be employed although in such cases there should preferably be water or aqueous vapor present in order to make them function properly. In addition to such acidic anhydrides, other gaseous materials may be used in certain instances such as aldehydes, for example formaldehyde, and as will be apparent, such may be used in solution as well as in the gaseous phase.

Likewise, the agent may be applied to the web in solid form. For example any solid acid, preferably finely powdered, such asoxalic acid, or

the like may be employed. In this case also water should preferably be present in the web to effect the solution of the agent in order that it may have the proper effect on the web. Among other agents which I may employ in addition to those mentioned are metallic compounds, preferably soluble, and thus in the claims where I use the term metallic compound I mean that such compound shall be substantially water soluble such for example as calcium compounds as calcium nitrate, or magnesium sulphate and the like, which may be non-acid or which may be acid, such as aluminum sulphate (ordinary alum) or other aluminum compound such as aluminum chloride, or stannous chloride, lead acetate and the like.

However in general, from the standpoint of economy and effectiveness, I prefer to use alum as my sizing afiecting agent and because of convenience in handling it, I prefer to apply it to. the web in aqueous solution.

The application, 1'. e. exposure, of the sizing afiecting agent in gaseous or vapor form to the web may take place when the web is either in the wet or in the dry condition, but preferably when it isin the wet condition, and will ordinarily require a container, hood or the like in which the sizing afiecting agent may be exposed to the web. This may suitably be provided by enclosing that part of the paper machine at which the exposure is to be made in' a suitable hood or enclosure or the like, which.may. be at atmospheric pressure. superatmospheric pressure, or sub-atmospheric pressure such as in a vacuum of suitable degree, as best meets the particular case; or such agent may be applied to the web, independently of the paper machine in a special applying device.

The application of a liquid to the web, andthis is my preferred method, may conveniently take place on the paper machine but here again as in the case of the gaseous agent, the liquid may if desired be applied to' the web as a process independent of the paper machine. The above statement relative to place of application ofa liquid is equally pertinent to the application of a solid. sizing aflecting agent. i

'The application of the sizing affecting agent to the web may take place while the web is either in the wet or the substantially dry condition, but in my preferred practice ot'using a liquid agent such as' alum solution,-I prefer to apply it to the already formed wet web after it has left the webfo'rming device, as this fits in most conveniently with the ordinary papermahng operation and does not usually require special drierssubsequent to the point of application of the agent, as might be the case if the agent were applied to the dried or almost dry web. It will be understood, however, that where I speak of applying a sizing affecting agent to the web, I mean to include in the definition of web and as within the scope of my invention not only the already formed wet or dry web, but also the web as .it exists in its formative or forming state at any point on the web-forming device, between the point of delivery of the mix to the web forming device and the point of delivery of the formed web from the web-forming device; and of course it will be understood that such application may take place to ether side of the web. that is, either the top or the bottom or to both. While the web is on said web-forming device this application will of course include the case where the agentmay be introduced not at the surface but within the forming web by suitable introducing devices.

In the application of the'sizing aifecting agent in solution to the web, anyknown form 0! device for applying liquids to a paper web may be employed; for example, the web may be passed through a trough or vat containing the solution, or the solution may be transferred to the wehby brushes, for example rotary brushes, or by'contact rolls, or by supply boxes or rolls on the press rolls or other rolls, or by spraying or the like. In the case of spraying the spray may be relatively coarse, or it may be very fine so as to be in theform of a mist, if desired.

In certainca'ses the sizing affecting agent may be applied by means of the felt or felts normally contacting with the web on the paper machine, or even by means of small independent travelling 15 felt or felts, or belts, contacting with the web. In such cases the agent may be applied previously to the felt, or the like, or may be applied at the nip of the contacting web and felt. However, the application by roll or rolls is as simple as any'and thoroughly practical, and hence is'a very convenient one to use. In order to obtain more complete penetration of the web by the sizing affecting agent, the web may be led over a suction box, roll, or the like at or subsequent to the point where the sizing affecting agent is applied to the opposite side of the web, particularly in the case where the sizing aflecting agent is applied only to one side of the web, or to the two sides at spaced intervals. If desired a felt, wire belt, or the like may be interposed between the suction device and the web to carry and/or support the web. In general the method of application in any given case is that which is best adapted for use at the particular point at which the agent is to be applied and should be chosen with regard to the particular conditions to be met in any given'case, all of which will be apparent to one skilled in the art.

As the agent is preferably applied continuously to the web, suitable means for supplying it to the applying device, for example pumps, should be employed, and the amounts applied should preferably vary regularly with the paper machine speed and be adjustable to the various grades and weights of paper run.

In order more clearly to demonstrate the method of practicing my invention, I give below an illustrative procedure which produces satisfactory results. A mix of fibre of any suitable kind is made for example in a beater, and to this is added size, for example rosin size, size precipitant for example alum, and alkaline filler. The size may be present for example in an amount of 2 per cent., computed as dry rosin on the air dry weight of the fibre, and the alum in an amount of 3 per cent. computed similarly, whereas the alkaline filler also similarly computed may be present in an amount of 20 per cent. After this mix has been suitably treated and is ready for delivery to a web-forming device, if paper be made therefrom, it will be found that said paper is substantially unsized, or at best only very slightly sized, although as explained above, there is present a potential sizing agent in the form of the deteriorated or destroyed sizing. This potential sizing agent is, in certain cases at least, not in a soluble form, but in an insoluble form, and there is some evidence to indicate that where rosin size is used and calcium carbonate is the filler, that the sizing which may originally be considered to consist of aluminum resinate has been converted into calcium resinate. However this may be, and it is to be distinctly understood that this is merely a theory, and that the results of my invention are in no way dependent upon this or any other theory, the mix which would otherwise produce an unsized or poorly sized sheet is run off on a paper machine equipped to apply alum to the web. This equipment may suitably be arranged at the presses, preferably the third press, or even better at the smooth rolls if the machine be equipped with such rolls. At such points the web has lost most, if not all of the water which it will lose by pressure,- and is in a reasonably absorbent condition. Thus, if the machine be equipped with third press rolls which may be operated preferably without felts, two applying rolls contacting directly with the two third press rolls may be used to apply the alum solution to the wet web. Of course, it will be understood that the contact rolls are supplied with the alum solution by appropriate means such as by immersion in supply boxes, troughs or the like, or by contact with other rolls carrying the alum solution, or other suitable means. Optionally, and in certain cases this is my preferred method, the alum may be applied by an applying roll which contacts directly with the web itself, and as will be apparent, either in this case or in the case of press roll application, the alum may be applied either to one or both sides, but the application to both sides of the web is the more general procedure. After the alum application, the paper may be dried in the customary manner if desired, and calendered or otherwise finished according tothe type of paper being made. The result of the application of this alum is that the paper instead of being unsized when it comes off the machine will now be found to be sized. It will be apparent that this is accomplished by extremely simple means which may comprise as stated merely an alum applying device adapted to be easily and simply attached to an ordinary paper machine.

While I do not limit myself to the concentration of alum solution to be applied, and it will be apparent that the concentration required will in any event be influenced by machine speed, type of paper manufactured, and other variables well known to one skilled in the art, nevertheless I can state that a 15 per cent. solution has been found to be satisfactory for my purpose, and this can be the one tried in practice first and then adjustment of the concentration may be made either one way or the other according to conditions. However, in certain cases, for example if suction is to be applied to the sheet to improve the penetration of the sizing affecting agent, a much more dilute solution may be employed, for

example 1 per cent. or thereabouts. Likewise the amount of alum to be applied is diflicult to state definitely owing to the variation in conditions, and type of paper made, but it may vary in certain cases from a fraction of a percent. on the total furnish up to several percent., and this quantity may be conveniently controlled by the agent applying device in conjunction with the adjustment of the concentration of the solution applied. I

As will be apparent my process may be employed in combination with other procedures disclosed in numerous of my prior patents and copending applications, including not only those mentioned herein previously, but others not speciflcally referred to previously herein. For example,it may be applied in conjunction with the process described in my copending application first above mentioned. In such an instance deteriorated or destroyed sizing or sizing capable of preservation or enhancement would already be present in a paper web, for improvement of the sizing by the present invention; and in addition extra sizing might be added to the web by the process described in said copending application by precipitating size in the web itself. It will be apparent that the sizing affecting agent may be applied to one side of the web only. Also if desiredother sizing methods'may be applied to the other side of the web; or the present and other procedures may be-applied to the same side, or to both sides; the use of any or all of these precedures as will be apparent depending upon the circumstances and the results to be obtained.

It will be apparent that the application of the sizing affecting agent to the web will contact such agent not only with the potential sizing of the web, but also with the alkaline filler contained therein. If the agent be one which does not substantially react with alkaline filler, this will merely result in the co-presence in the web of the alkaline filler and such amount of the agent as does not react with the potential sizing in the web. Of course, such amount of agent will in general be concentrated more nearly at one or both surfaces of the web than at the central portion of the'web, according as the application has taken place to one or both surfaces.

However if the sizing affecting agent be one which reacts with alkaline filler such as an acidic reagent, it will be apparent that the agent may to a certain extent react with the alkaline filler itself in the web either before, simultaneously with, or subsequent to, reacting with the potential sizing of the web. -As will-be apparentsuch action'will result in a change in the chemical composition of the alkaline filler, at least on the surface of the alkaline filler particles, the

reaction taking place more particularly with those particles of the alkaline filler which are near the, superficial part of the web, this action taking place either at one or both sides of the web according as the application of the agent is made to one or both sides of the web; and in certain cases as will be apparent the'pH value of the compound formed will be different from that of the alkaline filler itself, in most cases less. For example, if acetic acid be used as the agent and calcium carbonate as the filler, a certain amount of calcium acetate may be produced. On the other hand with calcium carbonate, an acid or an acid salt be used of which the calcium salt is substantially insoluble, that corresponding salt will be formed; for example if phosphoric acid or an acid phosphate be the agent used, calcium phosphate will be formed; if sulphuric acid or acid sulphate such as alum be used, calcium sulphate will be formed, as well as aluminum hydroxide or other aluminum compound where alum is used.

This formation is beneficial in certain cases as under ordinary conditions a paper filled with alkaline filler is more or less alkaline in reaction which, with certain inks and under certain conditions such for example as in the lithographic process, may be detrimental. However, by converting the alkaline filler, or at least the surface of its particles, at or near the surface or surfaces of the paper web, into a substantially neutral or even acidic compound, a paper is produced filled with alkaline filler which in its surface reaction may be of a different pH than its central portion, for example the surface reaction may be only mildly alkaline, i. e. less alkaline than the alkalinefiller employed, or neutral, or even acidic. This is due to the production of the corresponding diiferentpH value, or less alkaline, neutral, or even acidic compound of the'metallic radicle of the alkaline filler through the reaction of the sizing affecting agent with the alkaline filler in the paper web, and in certain cases to residual substantially unacted upon portions of the agent remaining in the web.

It will be apparent that where I use the term potential sizing I use it to include sizing in a number of possible conditions; and where I use it in the claims I mean it to include, among others, one or more of the following: (1) deteriorated sizing; (2) destroyed sizing; (3) undeveloped sizing; (4) underdeveloped sizing; (5)

sizLng substantially developed but capable of improvement; (6) sizing substantially effective or substantially undeteriorated but which would suffer deterioration during the drying process were it not prevented from being so affected; (7) unprecipitable sizing; (8) sizing comprising sizing agent, which of itself may be material substantially unaffected by alkaline filler, and which may be made eifective as sizing by associating it with the fibres of a mix by means of acidic material or the like, and which may not function properly as a sizing because of the lack of associating agent or the deterioration thereof; (9) similar to (8) except that instead of an individual material as fibre associating agent, a gathering precipitate for the sizing agent such as a small amount of rosin size and alum is used, (which may of itselfimpart sizing but which need not be present in an amount sufiicient of itself to impart sizing), and which sizing agent -may not function properly as a sizing because of It will be apparent, however, that I do not mean to include in the term potential sizing the case where there is added in the mix or to the web a soluble or emulsified sizing agent precipitable but theretofore un'precipitated, such case being covered by claims inimy copending application first above mentioned.

By the term alkaline filler" I mean substantially water insoluble filler which when agitated in contact with freshly boiled distilled water, say for an hour, will impart a pH value to such water greater than 7.0, that is, whichwill be on the alkaline side of the neutral point; 'Among fillers in this group may be mentioned 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 United States Patent No. 1,595,416, issued August 10, 1926; calcium carbonate magnesium hydroxide disclosed in my -or other physically associated mixtures of these with one or more other acid soluble materials of a substantially water insoluble nature. By the term alkaline filler I also intend 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 similar papers, broke", or the like.

Where I use the term size or sizing agent herein I mean to include any size suitable for sizing paper, such for example as rosin size of any known composition, saponifled fatty acids or waxes, emulsions of substantially non-saponifiable materials as paraflin, and the like.

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 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 various embodiments and examples of my invention, it is to be understood that the details of procedure and equipment, the proportions of ingredients, and the arrangement of steps may be widely varied without departing from the spirit of my invention or the scope of the subjoined claims.

I claim:

1. The method of manufacturing sized paper filled with alkaline filler comprising mixing fibrous material, alkaline filler, size, and size precipitant, forming a web therefrom, and applying sizing affecting agent to said web.

2. The method of manufacturing sized paper filled with alkaline filler, wherein material is added to the paper mix under conditions favoring the of the time of contact of the constituents of the mix, comprising mixing fibrous material, alkaline filler, size, and size precipitant, forming a web therefrom, and applying sizing afiecting agent to said web.

3. The method of manufacturing sized paper filled with alkaline filler comprising'providing a fibrous mix containing alkaline filler and potential sizing, forming a web therefrom, and apply ing sizing afiecting agent, to said web.

4. The method of manufacturing sized paper.

filled with alkaline filler comprising providing a fibrous mix containing alkaline filler and potential sizing, forming a web therefrom, and applying acidic material to said web.

5. The method of manufacturing sized paper filled with alkaline filler comprising providing a fibrous mix containing alkaline filler and potential sizing, forming a web therefrom, and applying metallic compound to said web.

6. The method of manufacturing sized paper filled with alkaline filler comprising providing a fibrous mix containing alkaline filler and potential sizing, forming a web therefrom, and applying alum to said web.

7. That step in a method of manufacturing sized paper filled with alkaline filler comprising applying sizing affecting agent to a paper web containing alkaline filler and potential sizing.

8. That step in a method of manufacturing sized paper filled with alkaline filler comprising applying acidic material to a paper web containing alkaline filler and potential sizing.

9. That step in a method of manufacturing sized paper filled with alkaline filler comprising applying metallic compound to a paper web containing alkaline filler 'and potential sizing.

10. That step in a method of manufacturing sized paper filled with alkaline filler comprising applying alum to a paper web containing alkaline fillerand potential sizing.

11. That step in a process of manufacturing sized paper filled with alkaline filler comprising substantially preservingthe sizing in a paper web containing alkaline filler and sizing, by the application of a sizing affecting agent to said paper web.

12. That step in a process of manufactin'ing sized paper filled with alkaline filler comprising substantially developing the sizing in a paper web containingalkaline filler and one of a group of materials comprising sizing capable of improvement, deteriorated sizing, destroyed sizing, undeveloped sizing, and underdeveloped sizing, by the application of; a sizing affecting agent to said paper web.

l3. Sized paper filled with alkaline filler, at least one surface of which paper is less alkaline than said alkaline filler.

14. Sized paper filled with alkaline filler, said paper being'less alkaline at at least one of its surfaces than it is in its central portion.

15. Sized paper filled with alkaline filler, at least one surface of which paper is substantially non-alkaline.

l6. Sized paper filled with alkaline filler, at leastone surface 'of which paper is acidic.

l7. Sized paper filled with alkaline filler having a conversion product formed in situ from alkaline filler, adjacent at least one of the surfaces of said paper.

l8. Sized paper filled with alkaline filler, the particles of said filler near the surface of said paper having a coating thereoncomprising a compound of a lower pH value than said alkaline filler, said'co'mpound having a higher concentration adjacent at least one of the surfaces of said paper than it has at the central portion of said 19. Sizedpaper filled with alkaline filler, having a substantially non-alkaline compound formed in situ from alkaline filler adjacent at least one of the surfaces of said paper.

. 20. Sized paper'filled with alkaline filler comprising calcium carbonate at least part of which is superficially coated with a reaction product of a pH value different from said calcium carbonate, said reaction product being formed in situ.

21. Sized paper filled with alkaline filler comprising calcium carbonate at least part of which is superficially coatedwith calcium sulphate.

22. Sized paper filled with alkaline filler, containing residual substantially unafiected sizing affecting agent adjacent at least one of the surfaces of said paper.

23. Sized paper filled with alkaline filler, the

sizing eflect therein decreasing substantially gradually from at least one surface thereof toward the center of the web.

HAROLD ROBERT RAFI'ON.