EP0763159B2 - Method for making paper - Google Patents

Abstract

PCT No. PCT/FR96/00468 Sec. 371 Date Jan. 13, 1997 Sec. 102(e) Date Jan. 13, 1997 PCT Filed Mar. 28, 1996 PCT Pub. No. WO96/30591 PCT Pub. Date Oct. 3, 1996The invention relates to a new process for the manufacture of paper which employs, in the fibrous composition, a cationic starch exhibiting a high level of fixed nitrogen, namely greater than 0.95%, and a polyaluminum compound, such as a (basic) aluminum polychloride or an aluminum polychlorosulphate. This process makes it possible, including under difficult conditions (fibrous composition based on old papers, significant closure of the circuits), to improve the level of retention of starch and the physical characteristics of the paper, indeed to increase the machine speed by dispensing with the surface treatment optionally applied to the paper. The process according to the invention is particularly suitable for the manufacture of paper for graphical use or of paper for wrapping or packaging and very particularly of fluting paper or of liner paper for corrugated fiberboard.

Description

• de fibres synthétiques telles que les fibres de polyamides, de polyesters et de résines polyacryliques,
• de fibres minérales telles que les fibres d'amiante, de céramique et de verre,
• de toutes combinaisons de fibres cellulosiques, synthétiques et minérales.

The subject of the invention is a new process for manufacturing paper according to claim 1, and a use according to claim 11, the term "paper" designating in the following any flat structure or sheet not only based on cellulosic fibers - material first most frequently used in the paper and cardboard industry - but also based on:

• synthetic fibers such as polyamide, polyester and polyacrylic resin fibers,
• mineral fibers such as asbestos, ceramic and glass fibers,
• all combinations of cellulosic, synthetic and mineral fibers.

The well-known use of cationic starches which are introduced into the mass of fibers before formation of the sheet, generally made it possible to increase the retention of fibers and fillers, to improve drainage and to increase the physical characteristics of the paper. Indeed, the preferential fixation of these starches on the sites anionic reaction of fibers and fillers, made possible by their cationic or cationic nature, allows increase the number of connections between fibers as well as between fibers and fillers, resulting in greater resistance of the paper. Thanks to this greater resistance of the paper, it became possible to decrease the concentration of the mass of fibers or to use lower quality fibers.

However, it turns out that, for a few years, the aforementioned advantages obtained by the implementation cationic starches do not always make it possible to compensate for the increasing disadvantages created by the degradation increasing the quality of raw materials.

Indeed, in order to face increasingly strict economic profitability concerns, not only the dough semi-chemical traditionally used for example for the production of paper for corrugated board has seen its share reduced in favor of pulps from recovered cellulosic fibers, commonly called FCR, but moreover the quality even of these FCR is more and more mediocre due to the increasing number of recycling of "old paper".

Added to this is the fact that in paper machines, the trend is more and more towards closure systematic circuits, resulting in enrichment of the production water with suspended, organic and mineral. Among these undesirable or polluting materials, there are, in particular, physicochemical species very varied, including colloidal in nature, presenting an anionic character and commonly grouped under generic terms of "anionic trash" or "anionic waste".

Their ever-increasing presence in manufacturing waters means that any cationic starch used work happens to be always more used to neutralize or settle on said anionic waste and, correspondingly, always less available to attach to the reaction sites of fibers, hence an increase in the rate starch not retained on the sheet and less resistance of the latter.

In general, whatever the degree of cationicity of the starches, the closure of the circuits and the degradation of fiber quality results in an inevitable drop in efficiency (including retention on sheet) of the starches and the solidity of the papers as well as by an almost systematic increase in needs for the treatment of sewage from paper machines also known as "canvas water".

Assuming that the effectiveness of a cationic starch should be greater the greater its probability was important, we used to increase the likelihood of associations of the “cationic starch - polyacrylamide” type (US Pat. No. 4,066,495), “cationic starch - alumina sulfate” or "cationic starch - basic aluminum salt" (patent FR 2,418,297).

Recourse has also been had, as described in European patent EP 0 139 597 issued in the name of the Company Applicant, to “cationic cereal starch and cationic tuber starch” associations, said starches cationically advantageously exhibiting, according to the examples of said patent, a nitrogen level fixed on a relatively dry basis low, namely between 0.20 and 0.30%.

The aforementioned technology combining cationic starch and basic aluminum salt has been the object, in particular since the end of the 1980s, numerous studies aimed at remaining constantly adapted to the requirements technical (general quality of the paper), economic (speed of the machines, in particular) and regulatory (environmental protection in particular) which the paper manufacturers have to face.

These requirements had in particular the effect of recommending, as described in European patent EP 0 276 200, to associate a cationic polysaccharide and an aluminum compound of an anionic nature, which is generally formed in situ by the use of alkali, under conditions such that the pH of the fibrous mass must be kept at a precise value (7 to 8) at a specific location on the paper machine, i.e. immediately before headbox.

1) pour des ratios molaires très précis entre anions (apportés par l'alcali - exemples : OH^- ou CO₃ ^2-) et cations (Al³⁺, apportés par le composé aluminium),

2) et pour un ordre précis d'introduction des additifs dans la masse fibreuse, à savoir le composé aluminium puis le polysaccharide cationique.

Reading this patent EP 0 276 200 shows however that such anionic aluminum compound / cationic polysaccharide associations only make it possible to obtain the desired effect, namely obtaining good charge or fine retention, only under conditions specific operating procedures and in particular:

1) for very precise molar ratios between anions (provided by the alkali - examples: OH ^- or CO ₃ ^2- ) and cations (Al ³⁺ , provided by the aluminum compound),

2) and for a precise order of introduction of the additives into the fibrous mass, namely the aluminum compound then the cationic polysaccharide.

Note also that patent EP 0 276 200 in no way discloses the retention rate that can be obtained with regard to the cationic starch used (product "CATO 102" having a fixed nitrogen content of 0.30% approximately), nor the physical characteristics of the paper resulting from the implementation of such associations cationic polymer / anionic aluminum compound ".

• soit, comme décrit dans le brevet européen EP 285.486, d'augmenter le niveau d'introduction de l'amidon cationique jusqu'à des taux de l'ordre de 5 % exprimé en poids par rapport au poids de fibres et ce, en association avec un polychlorure d'aluminium lequel est, de préférence, mis en oeuvre le plus près possible de la caisse de tête de la machine à papier,
• soit, comme décrit dans le brevet européen EP 285.487, de maintenir des taux relativement faibles d'amidon cationique (0,3 - 0,4 % en poids de fibres) mais en associant obligatoirement ledit amidon, outre à un polychlorure d'aluminium, à une charge minérale (notamment du carbonate de calcium) et à un agent de collage (notamment de type alkyl cétène dimère ou "AKD" ou de type anhydride d'acide succinique ou "ASA").

The technical, economic and regulatory requirements mentioned above have had the effect of also recommending:

• or, as described in European patent EP 285,486, of increasing the level of introduction of cationic starch up to rates of the order of 5% expressed by weight relative to the weight of fibers and this, in combination with a poly aluminum chloride which is preferably used as close as possible to the headbox of the paper machine,
• either, as described in European patent EP 285,487, to maintain relatively low levels of cationic starch (0.3 - 0.4% by weight of fibers) but by necessarily associating said starch, in addition to a polychloride of aluminum, to a mineral filler (in particular calcium carbonate) and to a sizing agent (in particular of the dimeric alkyl ketene type or "AKD" or of the succinic acid anhydride type or "ASA").

Note that these two adjustments made to the "cationic starch - basic aluminum salt" technology mainly expressed for pH "in headbox" of a value of 7.2 or higher (up to 7.8) and this, respectively, for the production of "corrugated cardboard" type paper, coated with starch native (EP patent 285,486) or of the "printing and writing", "offset printing" or "reprography" type (EP patent 285 487).

Furthermore, these two documents in no way disclose the retention rate of the cationic starch used. work and, by difference, the level of cationic starch which may not have fixed within the forming sheet and, by even contribute to organic pollution and the non profitability of the system.

Furthermore, no details are given as to the nature of the cationic starch used in the context of these two documents (fixed nitrogen level, viscosity, botanical origin, etc.).

Very recently, it has been envisaged to combine different starches of variable cationicity (DS from 0.032 to 0.11 corresponding to nitrogen levels from 0.28 to 0.95) to various synthetic products capable of reducing undesirable effects inherent in the presence in the circuits of anionic waste (GLITTENBERG et al. in "PAPER TECH-NOLOGY", Vol 35 N ° 7, pp 18-27).

It appears that among these anionic waste sensors ("anionic trash catchers") PEI type products (polyethylene imine) or p-DADMAC (poly di alkyl dimethyl ammonium chloride) are more effective than a polychloride aluminum (the chemical composition of which is not specified), which is presented as "practically ineffective in terms of retention. "

• ne décrit aucunement les caractéristiques physiques du papier que l'on peut obtenir en associant un amidon cationique et un polychlorure d'aluminium,
• montre que pour certains paramètres un amidon cationique de DS 0,11 n'est pas significativement plus efficace qu'un amidon cationique de DS de 0,032 ou 0,035,
• n'étudie réellement les caractéristiques physiques du papier, évaluées sur "Formette de Rétention", que dans le cadre d'associations amidon cationique / P-DADMAC et ce avec mise en oeuvre d'un amidon (produit C* BOND 05906) lequel est connu pour présenter un taux d'azote relativement peu élevé, en tous cas inférieur à 0,5 %,
• détourne globalement l'homme de l'art d'envisager des amidons cationiques de plus hauts DS, et donc de taux d'azote plus élevés, lesquels seraient "non intéressants d'un point de vue économique".

In any event, we note that this document:

• in no way describes the physical characteristics of the paper which can be obtained by combining a cationic starch and a polychloride of aluminum,
• shows that for certain parameters a cationic starch with DS 0.11 is not significantly more effective than a cationic starch with DS of 0.032 or 0.035,
• really studies the physical characteristics of the paper, evaluated on "Retention Form", only in the context of cationic starch / P-DADMAC associations and this with the use of a starch (product C * BOND 05906) which is known to have a relatively low nitrogen level, in any case less than 0.5%,
• globally diverts those skilled in the art to consider cationic starches with higher DS, and therefore higher nitrogen levels, which would be "not interesting from an economic point of view".

In order to improve the efficiency of cationic starches, the solidity of the papers and / or to lower the undesirable suspended matter contained in canvas water and secondary effluents ("clarified water"), it has also been proposed to use polysaccharide binders, and in particular starches, containing both cationic groups and anionic groups as described in patents FR 2,289,674, EP 257,338 and patent application WO 81/00147.

Patent FR 2,289,674 describes the specific implementation, in media highly concentrated in sulfate alumina, amphoteric starches of the sulfo-succinate type with reduced cationicity (degree of substitution or "DS" announced 0.03 corresponding to a fixed nitrogen level of less than 0.30% relative to the dry weight of the starch) and this, in view improve the retention of titanium dioxide pigments. In some cases, the physical characteristics of the paper, expressed by the MULLEN index alone, can be improved but in a very limited way (MULLEN max. obtained: 1.59).

Patent EP 257,338 describes the specific use of amphoteric starches of the phosphate type, in particular waxy base, cationicity qualifying as "low" or "medium" (maximum DS of 0.08 corresponding to a rate fixed nitrogen less than 0.7% / dry weight of starch). This document considers the interest of such amphoteric starches only for the sole purpose of improving the drip performance of the paper machine.

Patent application WO 81/00147 describes the preparation, by a complicated process, of an amphoteric mucus based on cationic starch of reduced cationicity and a CMC type polymer, intended to coat a structure filler / fiber.

In any event, the complexity and cost of preparation, insufficient performance and / or potential of limited application of such amphoteric starches reduce their industrial interest.

In order to improve the efficiency of cationic starches, the solidity of the papers and / or to lower the levels pollution of effluents from the paper industry, so-called "dual" techniques have also been recommended by which are combined on the one hand with cationic polymers and on the other hand with anionic compounds of mineral origin and / or organic. Such a technique, using separately a cationic starch and an anionic starch, is particularly recommended in patent EP 282,415 of which the Applicant Company is the holder.

Another dual technique is also described in patent EP 41,056, claiming the association between cationic starch and colloidal silicic acid. Such an association has been improved over time as it follows of the description of patent application WO 86/00100 (anionic agent of the aluminum silicate or silicic acid type modified by aluminum), of patent EP 348,366 (anionic agent of the polymeric silicic acid type having a specific surface area) and of patent EP 490,425 (cationic agent containing from 0.05 to 0.5% by weight of aluminum).

In general, it appears that the dual technique using a silicic derivative as that anionic agent had to be considerably complexed over time in order to meet the requirements (technical, economic and / or regulatory) increasingly pressing with the paper manufacturers.

• des systèmes ternaires "amidon cationique (DS = 0,035) / polymère d'acide silicique particulier / sel d'aluminium" comme décrit au niveau du brevet EP 349.366 précité, ledit sel d'aluminium étant préférentiellement choisi parmi l'alun, l'aluminate de sodium ou le chlorure d'aluminium, et
• en dernier lieu, des systèmes binaires mettant en oeuvre des amidons cationiques porteurs d'aluminium préparés selon des procédés complexes comme il résulte de la lecture des brevets EP 303.039 ou EP 303.040, cités au niveau du brevet EP 490.425 susmentionné.

We were thus led to design:

• ternary systems "cationic starch (DS = 0.035) / particular silicic acid polymer / aluminum salt" as described in the abovementioned patent EP 349,366, said aluminum salt being preferably chosen from alum, aluminate sodium or aluminum chloride, and
• lastly, binary systems using cationic aluminum-bearing starches prepared according to complex processes as results from the reading of patents EP 303,039 or EP 303,040, cited in the above-mentioned patent EP 490,425.

In addition, patents EP 349,366 and 490,425 are mainly focused on the "draining" and / or "retention" and do not really address the study of the physical characteristics of the paper.

These dual techniques based on silicic derivative lead, as pointed out, to an improvement in the retention, thus making it possible to manufacture paper with a higher content of fillers. They allow savings substantial amount of cellulose, but is not applicable in all cases. In addition, the amount of starch attached to the cellulose at the time of sheet formation still being limited, the physical characteristics of the paper obtained are not always improved enough.

In order to improve the physical characteristics of a loaded and glued paper, it has recently been recommended (EP 522,940 patent) much more sophisticated systems made up of a so-called "retention system" based on three constituents, in this case a cationic starch (DS from 0.01 to 0.1 corresponding to fixed nitrogen levels <0.9%), of an anionic polychloride of aluminum and silica, constituents whose introduction rates must, in addition, be included in very specific ranges.

It is found that if such a ternary retentive system, based on the synergy of silica / poly aluminum chloride, specifically improves the appearance of the paper (i, e the homogeneity of the fibers in the plane and the thickness of the sheet), said system does not achieve retention rates (total retention) of the order of at least 80%.

It follows from all of the above that there is a real need to provide a means for make paper that is both simple, cost-effective, non-polluting and capable of meet the current requirements of paper manufacturers in particular in terms of the nature of the raw material (FCR for papers for corrugated board for example), quality of the finished product (sheet resistance in particular), productivity (machine speed).

In particular, there is a real need to find a way to make paper under conditions meeting the wishes of the practice and which does not impose the systematic use of starches amphoteric, starches of different ionicities and / or complex silica-based systems.

And the merit of the Applicant Company was to find that such a means could be established, including under conditions deemed difficult (pulp made of FCR or old paper, significant closure of circuits), by using on the one hand a cationic starch having a sufficiently high nitrogen content and on the other hand of a particular aluminum compound.

More specifically, the present invention relates to a process for manufacturing paper from a fibrous composition characterized in that said fibrous composition is brought into contact, simultaneously or not, with at least one cationic starch having a fixed nitrogen level greater than 0.95%, expressed on the dry weight starch and with at least one polyaluminium compound.

The cationic starches used in accordance with the invention can be obtained by any technique current or future, in aqueous medium, in solvent medium or in dry phase, capable of allowing one or more group (s) nitrogen (s) of an electropositive nature to be fixed on a starch or a mixture of starches of all kinds and origins when the nitrogen level thus fixed is greater than 0.95% by weight of dry starch.

• brevet FR 2.434.821, en particulier de la page 3, ligne 29 à la page 5, ligne 10,
• brevet EP 139.597, en particulier colonne 1, lignes 30 à 52, et
• brevet EP 282.415, en particulier page 4, lignes 5 à 36.

Said nitrogen groups may in particular contain a tertiary or quaternary nitrogen atom such as the reagents described in the following patents, filed in the name of the Applicant:

• Patent FR 2,434,821, in particular from page 3, line 29 to page 5, line 10,
• EP 139,597, in particular column 1, lines 30 to 52, and
• Patent EP 282,415, in particular page 4, lines 5 to 36.

The cationic starches used in the process according to the invention can in particular be prepared by one any of the cationization techniques, in particular dry phase cationization, described in the patents FR 2,434,821, FR 2,477,159, EP 233,336, EP 303,039, EP 333,292, EP 406,837, US 4,332,935 and US 429,444.

The cationic starches used according to the invention can moreover be of a "polycationic" nature. such as those described in the aforementioned patents EP 406,837 and US 429,444 since said starches have, in fine, a fixed nitrogen level greater than 0.95% on the dry weight of starch.

Preferably, in the context of the invention, use is made of starches having a fixed nitrogen level from about 1.0% to about 3.0%, preferably from about 1.0% to about 2.5%, and even more preferably from 1% to 1.6%, based on the dry weight of starch.

Said starches, of natural or hybrid origin, can be based on potato, potato with high amylopectin content (waxy starch), corn, wheat, high amylopectin corn (waxy corn), corn high amylose, rice, pea or cassava content, based on cuts or fractions that can be made or obtained such as amylose, amylopectin, particle size sections known to those skilled in the art under the terms of starch wheat "A" and wheat starch "B", and any mixtures of at least any two of the above products.

As such, the cationic starch which can be used for the production of paper according to the invention can in particular be consisting of a mixture of at least one cationic tuber starch, in particular potato starch cationic and at least one cationic cereal starch, in particular cationic corn or wheat.

It is possible in particular to use mixtures having weight ratios of starch of apple cationic soil / wheat or cationic corn ranging from approximately 10/90 to approximately 90/10, and in particular from 20/80 to 80/20, being understood that the cationization may have been carried out, as described at the level of patent EP 139,597 in the name of the Applicant, on the mixture of the two starches or, separately, on each of the two starches, which are then mixed.

The cationic starches used in the papermaking process according to the invention, which have a fixed nitrogen level greater than 0.95% on the dry weight of starch, can simultaneously, previously or after cationization, have been subjected to any chemical and / or physical treatment.

The chemical treatment may in particular consist of one or other of the known crosslinking techniques, oxidation, alkaline treatment, acid and / or enzymatic hydrolysis, esterification or plasticization.

By crosslinking technique is meant in particular any process involving an agent such as acid adipic acid or one of its derivatives, a halohydrin (for example epichlorohydrin), a trimetaphosphate (for example sodium), phosphorus oxychloride or a resin (for example based on formalin).

The term “oxidation technique” is understood to mean in particular any non-degradative oxidation process making it possible to substitute at least one OH group for the starch with a COOH group.

Among such processes, advantageously use the so-called "selective" oxidation techniques, that is to say allowing the substantial oxidation of the terminal hemiacetal function only of the starting starch, which can already be cationized before being selectively oxidized. Such techniques are described, among others, at the level of European patents EP 23 202 and EP 562 927.

The term “esterification techniques” means in particular any process which makes it possible to substitute starch (already cationized or not), at least in one place, by acetate, phosphate, succinate, sulfo-succinate, alkenyl-succinate groups, sulfate, maleate, propionate or carboxyl.

As a result, the starches used in the papermaking process according to the invention can be consist of amphoteric starches, i.e. products which are both cationic (fixed nitrogen level greater than 0.95% / dry weight of starch) and anionic.

In terms of physical modification, cationic starches can easily be used (in order to be contacted with the fibrous composition) in the form of dilute aqueous adhesives of variable concentrations, generally less than 20%, preferably between about 15% and about 1%.

The preparation of the adhesives is carried out in a manner known per se, by discontinuous or continuous cooking, by example, at 110-130 ° C, in a continuous pressure cooker or "jet-cooker" suitable for ensuring the operations of dosing, cooking and dilution.

According to an advantageous embodiment of the invention, it may be proposed to present the starch under the form of an uncooked or pregelatinized starch powder, this prior to and / or when it is brought into contact with the fibrous composition.

The Applicant Company has observed in particular that the high level of fixed nitrogen characteristic of starches used in the context of the invention could allow the latter to dissolve satisfactorily (i.e. not instantaneously but gradually) under temperature conditions very significantly lower than those adopted in jet-cooker, for example at temperatures between 10 and 50 ° C approximately. So powders starch can advantageously be brought into contact, by any suitable means, with fibrous compositions of which the temperature is brought and / or maintained by any suitable means to a value of about 25 ° C to about 50 ° C.

Thus, the present invention allows it, inter alia and by the nature of the starches which it implements, to simplify certain paper-making processes by eliminating traditional means of continuous cooking or discontinuous starch.

According to another variant of the method according to the invention and regardless of how it will be then cooked and used in stationery, the cationic starch has a viscosity of approximately 300 to approximately 3000, preferably from 350 to 2500, BRABENDER units (UB).

Said viscosity is measured on a "BRABENDER 350 CMG" type device. A starch sample (25.0 g) is used in sufficient water to obtain a total charge of 480 g. This is introduced in the baking chamber of the viscometer. Cooking is done in a controlled manner (1.5 ° C / min) and we appreciate the viscosity of the adhesive after it has been worn and then maintained for 20 minutes at a temperature of 92 ° C.

For information only, the Applicant Company has observed that cationic starches having a nitrogen level fixed from 1 to 1.6% and a viscosity of 900 to 2100 BU were particularly of interest within the framework of the present invention.

According to another variant of the process according to the invention, the cationic starch and the fibrous composition are put in contact under conditions such that said cationic starch represents from about 0.2 to about 6%, preferably from 0.3 to 4%, and even more preferably from 0.7 to 3%, of the weight of said fibrous composition.

Furthermore and as already specified, in the context of the present invention the particular cationic starch such that described above is associated with at least one "anionic waste sensor" of a particular type, namely a compound polyaluminum.

1. les sels de formule : Al_n(OH)_mX_{3n- m} dans laquelle X est Cl, NO₃ ou CH₃COO, n est quelconque, 3n-m est positif, m et n sont des nombres entiers positifs ; ledit sel pouvant contenir en outre un anion polyvalent Y choisi parmi les anions des acides sulfurique, phosphorique, polyphosphorique, silicique, chromique, carboxylique et sulfonique, le rapport molaire Y/Al étant de préférence compris entre 0,015 et 0,4 et la basicité ou le rapport m/3 n étant compris entre 0,1 et 0,9, de préférence entre 0,2 et 0,85. De tels sels peuvent notamment être constitués ou se rapprocher des produits "TEN-FLOC 18" ou "PAC 18" et "EKOFLOCK" fournis par EKA-NOBEL ou AKZO-NOBEL ;

2. les sels de formule : Al_n(OH)_mCl_3n-m-2k(SO₄)_k dans laquelle k, m et n sont des entiers positifs, et 3n > m + 2k, la basicité ou le rapport m/3n est, de préférence, compris entre 0,3 et 0,7 et k/n de préférence compris entre 0,01 et 0,03.

3. les sels de formule : (Al_n(OH)_{3n- m-2p} Cl_m(SO₄)_p)Z dans laquelle (3n- m- 2p)/3n = 0,4 à 0,7 ; p = 0,04 à 0,25 n ; m/p = 8 à 35 ; k, m, n, et p sont des nombres entiers et z est au moins 1 ;

4. les chlorosulfates d'aluminium basiques de formule : Al_nOH_m(SO₄)_kCl_3n-m-2k dans laquelle la basicité ou le rapport molaire (m/3n)x100 est généralement compris entre 40 % environ et 65 % environ, qui présentent un rapport équivalent Al/équivalent Cl de préférence compris entre 2,8 et 5. Un sel correspondant à la formule IV consiste notamment en le WAC fourni par ELF-ATOCHEM ;

5. les sels de formule : (Al(OH)x(SO₄)y(H2O)₃)n ou x = 1,5 à 2,0 ; y = 0,5 à 0,75, x + 2y = 3 et z = 1,5 à 4,0.

By “polyaluminium compound” in the sense of the present invention, is meant in particular the products which are commonly called “aluminum polyhydroxide” “aluminum polychloride”, “basic aluminum polychloride”, “basic aluminum polychloride "or" aluminum polysulfate "and preferably consists of one or more of the following products:

1. the salts of formula: Al _n (OH) _m X _{3n- m} wherein X is Cl, NO ₃ or CH ₃ COO, n is any, 3n-m is positive, m and n are positive integers; said salt possibly containing a polyvalent anion Y chosen from anions of sulfuric, phosphoric, polyphosphoric, silicic, chromic, carboxylic and sulfonic acids, the molar ratio Y / Al preferably being between 0.015 and 0.4 and the basicity or the ratio m / 3 n being between 0.1 and 0.9, preferably between 0.2 and 0.85. Such salts can in particular consist of or come close to the products "TEN-FLOC 18" or "PAC 18" and "EKOFLOCK" supplied by EKA-NOBEL or AKZO-NOBEL;

2. the salts of formula: Al _n (OH) _m Cl _3n-m-2k (SO ₄ ) _k in which k, m and n are positive integers, and 3n> m + 2k, the basicity or the ratio m / 3n is preferably between 0.3 and 0.7 and k / n preferably between 0 , 01 and 0.03.

3. the salts of formula: (Al _n (OH) _{3n- m-2p} Cl _m (SO ₄ ) _p ) Z in which (3n- m- 2p) / 3n = 0.4 to 0.7; p = 0.04 to 0.25 n; m / p = 8 to 35; k, m, n, and p are whole numbers and z is at least 1;

4. basic aluminum chlorosulfates of formula: Al _n OH _m (SO ₄ ) _k Cl _3n-m-2k in which the basicity or the molar ratio (m / 3n) x100 is generally between approximately 40% and approximately 65%, which have an Al equivalent / Cl equivalent ratio preferably between 2.8 and 5. A salt corresponding to the formula IV consists in particular of WAC supplied by ELF-ATOCHEM;

5. the salts of formula: (Al (OH) x (SO ₄ ) y (H2O) ₃ ) n or x = 1.5 to 2.0; y = 0.5 to 0.75, x + 2y = 3 and z = 1.5 to 4.0.

According to a variant of the invention, the polyaluminium compound advantageously consists of a salt of formula I, II, IV or V and consists in particular of a product of the WAC, PAC 18 or EKOFLOCK type.

• demande de brevet FR 2.418.297, page 2, lignes 1 à 14,
• demande de brevet EP 522.940, page 3, lignes 19 à 49, et
• demande de brevet WO 94/01619, page 4, ligne 6 à page 5, ligne 17.

Such polyaluminium compounds are described in particular in the aforementioned documents:

• patent application FR 2.418.297, page 2, lines 1 to 14,
• Patent application EP 522,940, page 3, lines 19 to 49, and
• Patent application WO 94/01619, page 4, line 6 to page 5, line 17.

Preferably, the polyaluminum compounds used according to the present invention have an aluminum content, expressed as Al ₂ O ₃ , of approximately 8% to approximately 20% by weight, in particular from 10% to 18% by weight.

According to another variant of the process according to the invention, the polyaluminium compound and the fibrous composition are brought into contact under conditions such that said polyaluminium compound, expressed by weight of Al ₂ O ₃ , represents from approximately 0.01% to approximately 0.5%, preferably 0.015% to 0.4%, of the weight of said fibrous composition.

Regarding the conditions for contacting them, cationic starch, polyaluminium compound and the fibrous composition, it is worth emphasizing the very great and surprising flexibility of the manufacture of paper according to the invention.

Indeed and contrary to the general teachings of the prior art, the process according to the invention in no way imposes that the cationic starch be brought into contact with the fibrous composition before the polyaluminium compound, or conversely that the polyaluminium compound is brought into contact with the fibrous composition prior to cationic starch. The Applicant Company even observed that it was entirely possible bringing the cationic starch and the polyaluminum compound simultaneously or almost simultaneously into contact with the composition fibrous.

In addition, it has been found that the polyaluminium compound could, in particular in very closed circuits, be introduced, in whole or in part, at the same level as the canvas.

• mettre en contact l'amidon cationique avec la composition fibreuse entre un niveau correspondant au raffineur et un niveau se situant juste avant la caisse de tête, de préférence entre un niveau se situant juste après le raffineur et un niveau se situant juste avant la pompe de mélange de la machine à papier,
• mettre en contact le composé polyaluminium avec la composition fibreuse entre un niveau correspondant au raffineur et un niveau correspondant à la caisse de tête et/ou aux eaux sous toile et, de préférence, entre un niveau se situant juste après le raffineur et un niveau se situant juste avant la caisse de tête de la machine à papier.

Although it is possible, as explained above, to use the cationic starch and the polyaluminium compound in any order and at any place on the wet part of the paper machine, including the pulper at the headbox, we prefer:

• bringing the cationic starch into contact with the fibrous composition between a level corresponding to the refiner and a level located just before the headbox, preferably between a level located just after the refiner and a level located just before the paper machine mixing,
• bringing the polyaluminium compound into contact with the fibrous composition between a level corresponding to the refiner and a level corresponding to the headbox and / or the water under canvas and, preferably, between a level situated just after the refiner and a level located just before the headbox of the paper machine.

The polyaluminium compound can in particular be brought into contact with the fibrous composition between a level corresponding to the first vat in the wet part of the paper machine and a level just after the scrubber of the paper machine.

As has been specified, the cationic starch and the polyaluminum compound can be introduced into a indifferent order at the wet end of the paper machine, including being contacted simultaneously or almost simultaneously with the fibrous composition.

As a result, the time between contacting, respectively, either the cationic starch or the polyaluminum compound with the fibrous composition and contacting, respectively, either the compound polyaluminium or either the cationic starch with the fibrous composition, is generally at most equal to 120 minutes approximately and in particular between 0 and 60 minutes, preferably between 0 and 45 minutes, and more preferably between 10 seconds and 40 minutes.

In practice, we will generally consider delays of the order of 25 seconds to 35 minutes, in particular 30 seconds to 20 minutes between the respective use of the two products (cationic starch and polyaluminium compound, in any order).

As indicated above and as will result from the examples below, the manufacturing process paper according to the invention has, among other advantages, in addition to being simple and cost-effective, to allow, especially in difficult conditions (pulp made from FCR or old paper, significant closure of circuits), obtain good starch retention, improve the physical characteristics of the paper and ensure machine speed meeting the requirements of practice, or even improving said machine speed and therefore, overall, improve the profitability of the system.

And surprisingly and unexpectedly, the Applicant Company has found that the simultaneous implementation or not, of a polyaluminium compound and of a cationic starch whose fixed nitrogen content is high, in accordance with the invention made it possible, in particular, to remove all or part of certain surface treatments applied to the sheet after his training.

Indeed, to obtain a paper (in particular a paper obtained under difficult conditions) having characteristics acceptable, or increased mechanical, it is generally necessary to subject the paper produced to a surface treatment carried out in particular using a "size-press" type machine. Such treatment, applied to any one or both sides of the paper, generally allows to increase the proportion of starch, native or physically and / or chemically modified, entering into the constitution of this paper, thus giving it a better resistance.

However, such a solution is not satisfactory from an economic point of view, any additional operation being expensive. Going "size-press" entails, in addition to an additional cost related to the equipment and the additional operation of drying which it induces, a significant reduction, generally of the order of 15 to 25%, in the speed of the machines and therefore paper production.

As a result, the method according to the invention is characterized in that the paper obtained is not subjected, on any one of its two faces or even on all of its two faces, with no surface treatment putting using a starch, native or physically and / or chemically modified.

Another major advantage of the papermaking process according to the invention is, as indicated previously, to allow, compared to the techniques of the prior art, to obtain a starch retention rate improved without negatively influencing the physical characteristics of the paper and / or obtaining characteristics improved physical properties of the paper, without negatively influencing the starch retention rate.

In addition and quite remarkably, the process which is the subject of the present invention is capable, including included in difficult conditions (FCR-based pulp or waste paper, significant closure of circuits) to improve significantly both the starch retention rate and the physical characteristics of the paper, as it will be exemplified below.

In the context of the present invention, the concept of paper is not, as specified at the beginning of the description, in no way limiting and includes, in particular, papers for graphic uses (in particular for printing-writing, for inkjet printing, for offset printing, for reprography) and papers for wrapping and packaging (corrugated papers, for flexible packaging of the thin kraft type or others).

The Applicant Company has in particular observed that the process according to the invention was particularly well suitable for the production of cover or flute type paper for corrugated cardboard.

In particular, the method according to the invention makes it possible to obtain corrugated corrugated paper under conditions (starch retention, machine speed) improved compared to techniques of the prior art and / or having improved characteristics compared to said techniques.

• être appliqué à la fabrication de papier cannelure pour ondulé, non surfacé, présentant des caractéristiques physiques, tout à fait compatibles avec les exigences actuelles de la pratique, lesdites caractéristiques étant exprimées, comme indiqué ci-après, en "indice CMT" (selon norme NF Q03-044 ou ISO 7263) et en "indice MULLEN" (indice d'éclatement selon norme NF Q03-053 ou ISO 2758).

The Applicant Company in particular has highlighted that the process according to the invention is particularly suitable for:

• be applied to the manufacture of corrugated paper for corrugated, non-surfaced, having physical characteristics, entirely compatible with the current requirements of the practice, said characteristics being expressed, as indicated below, in "CMT index" (according to standard NF Q03-044 or ISO 7263) and in "MULLEN index" (burst index according to standard NF Q03-053 or ISO 2758).

As a result, the present invention is characterized in that the paper obtained is a paper for use graphic or paper for wrapping or packaging, in particular corrugated paper or cover paper for corrugated cardboard.

• un indice CMT 60 d'au moins 130 environ, de préférence d'au moins 135 environ, exprimé en N,
• un indice MULLEN d'au moins 1,65 environ, de préférence d'au moins 1,70 environ, exprimé en KPa/g.m^{2 -1}.

In particular, the process according to the invention makes it possible to prepare a corrugated paper for non-surfaced corrugated cardboard, with a grammage of 120 to 130 g / m ² , in particular obtained from old paper, having:

• a CMT 60 index of at least about 130, preferably at least about 135, expressed in N,
• a MULLEN index of at least about 1.65, preferably at least about 1.70, expressed in KPa / gm ^{2 -1} .

In addition, the fibrous composition which is used in the context of the present invention has, advantageously a so-called "neutral" or "pseudo neutral" pH, ie from about 6.0 to about 8.0, preferably from 6.1 to 7.1, said pH being able to be controlled or uncontrolled ("free pH") as may be the case under difficult conditions operating.

As a result of which the present invention is also characterized in that the fibrous composition has a pH, controlled or not, lying between approximately 6.0 and approximately 8.0 and preferably between 6.1 and 7.1.

In addition, said fibrous composition can contain and / or be brought into contact, if necessary, with one or more the other of the products recommended in the aforementioned patents at the level of the prior art, including at least one product chosen from anionic starches, such as phosphorylated or sulfosuccinylated starches, bonding agents such as dimer aklyl ketene and succinic acid anhydrides, fillers, such as calcium carbonate and kaolin, retention agents such as polyacrylamides, polyethylene imines, polyalkyl ammonium chlorides and other synthetic retention agents, silicic and aluminosilicon compounds

In particular, said fibrous composition can advantageously and at any time contain and / or be used in contact with a silica or aluminosilicon compound such as those described in patents EP 41 056 and EP 0 522 940 mentioned above and, optionally, a bonding agent and / or a filler.

This silicic or aluminosilicate compound can be introduced into the fibrous composition simultaneously starch or at a different time, posterior or anterior, usually spaced a few seconds to a few minutes from the moment of the introduction of said cationic starch.

As a result of which, the process for manufacturing paper according to the invention is also characterized in that the fibrous composition is brought into contact at any time before the formation of the sheet, with at least one silicic or aluminosilicon compound, in particular with a colloidal silicic acid, the particles of which have a specific surface of approximately 50 to approximately 1000 m ² / g, as well as possibly with at least one filler or a bonding agent.

The invention can be understood even better with the aid of the examples which follow and which show certain particularly advantageous modes of the paper manufacturing process according to the invention.

EXAMPLE 1

From a thick pulp based on old paper, a fibrous composition (pulp) is reconstituted, by dilution in water, having the following main characteristics: pH 6.6 Total concentration 16.8 g / l Soluble concentration 13.7 g / l Acidity 0.24 g / l Resistivity 150 ohms Total ash 12.4 g / l Soluble ash 8.9 g / l

In the context of this example, representative of difficult paper preparation conditions, we study the performance (starch retention rate, MULLEN index and CMT 60 index) of the various cationic or amphoteric starches below in association or not with a polyaluminium compound hereafter designated by the generic term of "CPA". STARCH A Cationic (potato) starch with a fixed nitrogen level of about 1% on the dry weight of starch. STARCH B 25/75 mixture of a cationic starch and a cationic wheat starch, with a fixed nitrogen level of approximately 1.2%. STARCH C Cationic starch at 0.8% fixed nitrogen. STARCH D Mixture 25/75 cationic starch / cationic wheat at 0.65% fixed nitrogen. STARCH E Waxy amphoteric phosphate starch corn starch with a fixed nitrogen content of 0.25%. STARCH F Amphoteric starch of the sulfosuccinate type with a fixed nitrogen level of 0.25%.

• lait à 10 % de matière sèche (MS),
• température de cuisson : 120°C,
• durée de cuisson : 20 secondes,
• dilution en ligne : 700 l/heure
• absence de pompe en sortie cuiseur.

All of these starches were prepared in the form of adhesives on a continuous cooking appliance under the following conditions:

• milk with 10% dry matter (DM),
• cooking temperature: 120 ° C,
• cooking time: 20 seconds,
• online dilution: 700 l / hour
• no pump at the cooker outlet.

These different cationic or amphoteric starches are tested in combination or not with a PCA, in this case "PAC 18" on a TECHPAP "automated retention form".

The implementation, for these tests, is carried out at a rate of 2% of starch and, when it is present, of 1% of CPA.

The contact time between the starch and the fibrous composition is 5 minutes. The contact time between the CPA (when it is used) and the fibrous composition is 6 minutes.

• taux d'amidon fixé, ci-après désigné "RA", en %,
• indice MULLEN, ci-après désigné "MULLEN", en KPa/g/m² (selon la norme NF Q03-053 ou ISO 2758),
• indice CMT 60, ci-après désigné "CMT", en N (selon la norme NF Q03-044 ou ISO 7263).

For each of the starches A to G, in combination or not with a CPA ("PAC 18"), the following parameters are measured:

• fixed starch rate, hereinafter referred to as "RA", in%,
• MULLEN index, hereinafter referred to as "MULLEN", in KPa / g / m ² (according to standard NF Q03-053 or ISO 2758),
• CMT 60 index, hereinafter designated "CMT", in N (according to standard NF Q03-044 or ISO 7263).

It should be recalled that the MULLEN index makes it possible to assess the burst strength of a paper (for example example corrugated roofing paper) subjected to hydrostatic pressure increasing perpendicularly on its surface, said index taking into account the grammage of said paper.

The CMT 60 index is particularly suitable for the evaluation of corrugated paper for corrugated cardboard and in particular to the determination of the flat compression resistance of such paper.

As reference tests, we study the performances obtained in the absence of any starch and any CPA (ESSAI 1) or in the absence of starch but in the presence of CPA (ESSAI 2).

The results obtained ("RA", "MULLEN" and "CMT" as defined above) are detailed below according to the type of starch and the presence or absence of CPA. TRIAL TYPE OF STARCH CPA RA MULLEN CMT 1 - - - 1.42 117 2 - + - 1.32 120 3 AT - 44 1.51 134 4 AT + 60 1.74 136 5 B - 46 1.53 133 6 B + 62 1.75 142 7 VS - 48 1.64 132 8 VS + 56 1.72 125 9 D - 25 1.63 140 10 D + 19 1.54 148 11 E - ND 1.61 138 12 E + ND 1.58 134 13 F - 38 1.63 146 14 F + 38 1.57 142

1) un amidon cationique non associé à un CPA (cf ESSAIS 3, 5, 7, 9 et 11) ne permet pas, dans les conditions de ces essais, d'obtenir un ensemble de performances totalement satisfaisant, notamment si l'on considère les taux de rétention en amidon (RA) et les indices MULLEN obtenus. En particulier, on n'obtient pas, en absence de CPA, de papier présentant simultanément, outre un bon RA (≥ 50 %), un indice MULLEN au moins égal à 1,65 et un indice CMT 60 au moins égal à 130,

2) un CPA non associé à un amidon cationique (of ESSAI 2) est totalement inefficace,

3) seuls les amidons cationiques (y compris d'un mélange d'amidons cationiques - cf ESSAI 6) présentant un taux d'azote fixé suffisamment élevé et associés à un CPA (cf ESSAIS 4 et 6), permettent d'obtenir un ensemble de performances satisfaisantes à savoir, outre un bon RA (≥ 50 %, notamment ≥ 60 %), des indices MULLEN et CMT 60 aptes à satisfaire aux exigences de la pratique,

4) la comparaison des résultats obtenus, respectivement, dans le cadre des ESSAIS 8 et 10 (non conformes à l'invention) et dans le cadre des ESSAIS 4 et 6 (conformes à l'invention) montre notamment les avantages apportés par un taux d'azote fixé supérieur à 0,95 % en termes d'indice CMT 60 et/ou d'indice MULLEN. On notera que dans le cas de l'ESSAI 8, la mise en oeuvre du CPA a baissé en outre l'indice MULLEN. En outre, l'ESSAI 10 montre des résultats particulièrement insatisfaisants en termes d'indice MULLEN et de RA, la valeur de ces paramètres étant par ailleurs abaissée de par la présence de PCA,

5) les propositions de l'art antérieur préconisant, de manière très générale et non spécifiquement en association avec un CPA, la mise en oeuvre d'amidons amphotères de type phosphate (cf ESSAI 12) ou de type sulfosuccinate (cf ESSAI 14) ne sont pas entièrement satisfaisantes notamment en termes d'indice MULLEN et de rétention d'amidon. On note d'ailleurs que la mise en oeuvre d'un CPA en association avec de tels amidons amphotères abaisse les performances, déjà moyennes, desdits amidons.

It follows overall from the above results that:

1) a cationic starch not associated with a CPA (cf. TESTS 3, 5, 7, 9 and 11) does not allow, under the conditions of these tests, to obtain a set of completely satisfactory performances, in particular if we consider starch retention rates (RA) and MULLEN indices obtained. In particular, in the absence of a CPA, one does not obtain paper having simultaneously, in addition to a good RA (≥ 50%), a MULLEN index at least equal to 1.65 and a CMT 60 index at least equal to 130,

2) a CPA not associated with a cationic starch (of ESSAI 2) is totally ineffective,

3) only cationic starches (including a mixture of cationic starches - see TEST 6) having a sufficiently high fixed nitrogen level and associated with a CPA (see TESTS 4 and 6), make it possible to obtain a set satisfactory performance, namely, in addition to a good AR (≥ 50%, in particular ≥ 60%), MULLEN and CMT 60 indices able to meet the requirements of the practice,

4) the comparison of the results obtained, respectively, in the context of TESTS 8 and 10 (not in accordance with the invention) and in the context of TESTS 4 and 6 (in accordance with the invention) shows in particular the advantages provided by a rate fixed nitrogen greater than 0.95% in terms of CMT 60 index and / or MULLEN index. Note that in the case of TEST 8, the implementation of the CPA also lowered the MULLEN index. In addition, TEST 10 shows particularly unsatisfactory results in terms of MULLEN index and RA, the value of these parameters being moreover lowered by the presence of PCA,

5) the proposals of the prior art recommending, very generally and not specifically in association with a CPA, the use of amphoteric starches of phosphate type (cf. ESSAI 12) or of sulfosuccinate type (cf. ESSAI 14) are not entirely satisfactory, in particular in terms of MULLEN index and starch retention. It should also be noted that the implementation of a CPA in association with such amphoteric starches lowers the performance, already average, of said starches.

The observations made above show the industrial advantages brought by the manufacturing process according to the invention, which makes it possible, among other things, by virtue of the physical characteristics which it confers on the paper obtained, to remove, if necessary, the subsequent paper surface treatment operations, including disadvantages in terms of cost, machine speed and productivity have been mentioned previously.

EXAMPLE 2

Furthermore, the Applicant Company has generally confirmed, on a TECHPAP form, the value of the process subject of the invention, in particular in terms of starch retention and / or chemical characteristics of the paper, in the circumstances defined below.

* TEST 15:

• fibrous composition: identical to the pulp tested in TESTS 1 to 14 ("PASTE 1"),
• starches used: 1% starch type A + 1% anionic starch type VECTOR R A180 sold by the Applicant,
• CPA implemented: 2% of "PAC 18",
• starch contact time A: 5 min,
• contact time PAC 18: 6 min,
• contact time VECTOR ^R A180: 1 min,
• paper weight: 123 g / m2.

Under these conditions, a MULLEN index of 1.71 and a CMT 60 index of 137 are obtained.

* TEST 16:

• fibrous composition: PATE 1,
• starch used: 2% starch A in the form of an uncooked starch powder,
• CPA implemented: 2% of "PAC" 18,
• starch contact time A: 6 min, with prior heating of 10 min at 45 ° C in order to dissolve the starch,
• PAC 18 contact time: 6 min,
• paper weight: 127 g / m ² .

Under these conditions, completely satisfactory physical characteristics are obtained (including u22n index CMT 60 of 136) and, in addition, an exceptional starch retention rate for such a type of fibrous composition, namely greater than 90%. This test shows that it is possible, within the framework of the invention, to use a starch uncooked, a fortiori pregelatinized, as soon as the operating conditions, upstream and / or even at the dough level, allow contact between cationic starch and CPA at an adequate temperature, for example from 20 to 50 ° C (in this case: 45 ° C), conditions which are used practically in certain paper manufacturers. We can thus bypassing the implementation of a conventional cooker, continuous or discontinuous.

* TEST 17:

• fibrous composition: pulp reconstituted from a thick pulp based on waste paper with a pH of 7.0, a total concentration of 7.17 g / l, a soluble concentration of 3.32 g / l and a resistivity of 457 ohms,
• starch used: 2% starch A,
• CPA used: 1% of basic aluminum polychlorosulfate of the "WAC" type,
• starch contact time A: 4 min 30,
• WAK contact time: 5 min
• paper weight: 135 g / m ² .

A MULLEN index is obtained under these conditions (fibrous composition different from PATE 1, in particular) (value: 1.80) and a particularly high starch retention rate (value: 95%).

Claims (11)

1. Process for the manufacture of paper from a fibrous composition, characterized in that the said fibrous composition is brought into contact, simultaneously or non-simultaneously, with at least one cationic starch exhibiting a level of fixed nitrogen greater than 0.95 %, expressed with respect to the dry weight of starch, and with at least one polyaluminium compound.
2. Process according to Claim 1, characterized in that the cationic starch exhibits a level of fixed nitrogen of approximately 1.0 % to approximately 3.0 %, preferably of 1.0 % to 2.5 % and more preferentially still between 1.0 % and 1.6 %.
3. Process according to either of Claims 1 and 2, characterized in that the starch is in the form of an uncooked starch powder or of a pregelatinized starch powder when it is brought into contact with the fibrous composition, the said fibrous composition preferably exhibiting a temperature of approximately 25°C to approximately 50°C.
4. Process according to one of Claims 1 to 3, characterized in that the polyaluminium compound is an aluminium polyhydroxide, an aluminium polychloride, a basic aluminium polychloride, a basic aluminium polychlorosulphate or an aluminium polysulphate, the said polyaluminium compound preferably exhibiting an aluminium content, expressed as Al₂O₃, of approximately 8 % to approximately 20 % by weight and more preferentially of 10 to 18 % by weight.
5. Process according to one of Claims 1 to 4, characterized:

   in that the cationic starch is brought into contact with the fibrous composition between a point corresponding to the refiner and a point lying just before the head box, preferably between a point lying just after the refiner and a point lying just before the mixing pump of the paper machine, and

   in that the polyaluminium compound is brought into contact with the fibrous composition between a point corresponding to the refiner and a point corresponding to the head box and/or to the white waters, preferably between a point lying just after the refiner and a point lying just before the head box of the paper machine.
6. Process according to one of Claims 1 to 5, characterized in that the time period between bringing either the cationic starch or the polyaluminium compound respectively into contact with the fibrous composition and bringing either the polyaluminium compound or the cationic starch respectively into contact with the fibrous composition is between 0 and 60 minutes, preferably between 0 and 45 minutes and more preferentially still between 10 seconds and 40 minutes.
7. Process according to one of Claims 1 to 6, characterized in that the paper obtained is not subjected, on either of its two faces or indeed on both its two faces, to any surface treatment employing a native or physically and/or chemically modified starch.
8. Process according to one of Claims 1 to 7, characterized in that the paper obtained is a paper for graphical use or a paper for wrapping or packaging, in particular a fluting paper or a liner paper for corrugated fibreboard.
9. Process according to one of Claims 1 to 8, characterized in that the fibrous composition exhibits a pH, controlled or uncontrolled, lying between approximately 6.0 and approximately 8.0 and preferentially between 6.1 and 7.1.
10. Process according to one of Claims 1 to 9, characterized in that the fibrous composition is brought into contact, at any time whatever before the formation of the sheet, with at least one silicic or aluminosilicic compound, in particular with a colloidal silicic acid, the particles of which have a specific surface of approximately 50 to approximately 1000 m²/g, and optionally with at least one filler or one sizing agent.
11. Use of a cationic starch exhibiting a level of fixed nitrogen greater than 0.95 % expressed with respect to the dry weight of starch and of a polyaluminium compound for the manufacture of paper, in particular paper for graphical use or paper for wrapping or packaging and very particularly fluting paper for corrugated fibreboard or liner paper for corrugated fibreboard.