EP2929929B1 - Method for producing an alkenyl succinic anhydride emulsion - Google Patents

Description

The present invention relates to a process for producing an alkenyl succinic anhydride (ASA) emulsion in an aqueous solution of cationic starchy material, it being understood that the oily phase is constituted by ASA, the starchy solution acting as a carrier of said emulsion. By aqueous solution of cationic starchy material is meant a composition containing at least one cationic starch in aqueous solution.

The method described in the present application does not implement a recirculation loop of the product at the emulsification unit, and carries out a dilution of the emulsion once it is manufactured: a product with granulometry both fine, monodisperse, stable for a while, and which limits the fouling in the pipes carrying the emulsion from the emulsion manufacturing facility to the paper machine. This provides an efficient method, simple to implement, on a papermaking production site, suitable for production rates compatible with the needs of paper machines.

The invention also relates to an installation for manufacturing an emulsion suitable for implementing the method.

In the sector of paper and other cardboard, so-called gluing operations are intended to confer on these supports improved properties, especially in terms of hydrophobization, resistance to the penetration of hydrophilic species such as water and aqueous inks. In this respect, so-called "bonding" compositions which contain hydrophobic substances are used.

One of the compounds frequently used in bonding compositions is alkenyl succinic anhydride or "ASA" (acronym alkenyl succinic anhydrid). This chemical species which is not miscible in water must be emulsified in order to be advantageously used in the form of a liquid product: this allows a good contact between the ASA and the cellulose fibers. The emulsion in question is an ASA emulsion in an aqueous solution of cationic starchy material; in the rest of the application, it may also be referred to simply as an emulsion.

To carry out this emulsification, it is known to use, concomitantly, aqueous solutions of cationic starchy materials of different natures, the starchy material being optionally modified; the function of such compositions is to prevent the coalescence of the ASA particles by positive ionization of the surface of the particles, and to bring the ASA particles closer to the fibers by an ionic mechanism. Broadly, a dry weight ratio of cationic starchy material / ASA of between 0.2 and 4 is used.

In addition to the ability to impart improved properties to the final product, the ASA emulsion in the aqueous solution of cationic starchy material must have a number of characteristics. In particular, it must have a great fineness of particle sizes, as well as a narrow spectrum of distribution of these sizes ("monodisperse" product). As explained in the document WO97 / 35068 A1 these parameters condition the effectiveness of the bonding composition vis-à-vis the hydrophobicity properties it is supposed to confer.

In this regard, it is well known that the presence of "coarse" particles is a source of fouling, in particular various materials in which the bonding composition passes, but also the drying of the paper machine by steam entrainment. of these coarse particles (which can sometimes lead to fires). Conversely, the "fine" particles of said composition will pass through the fibrous mat and will be carried into the process water during dewatering. It is therefore necessary to have a gluing composition in the form of an emulsion having a maximum of particles whose diameter is centered on an optimum size that the skilled person estimates between 1 micron and 1.5 microns.

The Applicant has recently developed a method of manufacturing an ASA emulsion in a composition of cationic starchy material, leading to a narrow particle size distribution and centered on an interval of between 1 μm and 1.5 μm and this, without temperature rise of the emulsion, a phenomenon that accelerates the hydrolysis of ASA. On this occasion, it demonstrated that the resulting emulsions indeed confer excellent hydrophobizing properties on the papers in which they are intended to be used.

The key to this process is based on a step of emulsifying an ASA / aqueous cationic amylaceous material in a single pass (that is to say without recirculation loop as in the prior art), while by adjusting the dry matter content of the initial aqueous solution of cationic starch material to between about 7% and 12% of its total weight. Such a method is taught by the document WO2013 / 186491 of the present Applicant.

Nevertheless, it appears that the emulsions thus manufactured do not exhibit a stable particle size distribution. It has thus been found that the average diameter of said particles is rapidly changing over time, sometimes to values of greater than 4 μm: it therefore deviates substantially from the optimum value sought by the paper manufacturer and as defined above, with a view to get an effective collage of the sheet of paper. However, it is not unusual for the paper machine to be stopped for several minutes, or even several hours, due to technical problems, for cleaning or maintenance operations. In this respect, it is essential that the particle size distribution of the particle size of the emulsion does not vary.

Having conducted intensive work in this area, the Applicant has succeeded in improving the process that is the subject of the aforementioned Patent Application, so as to overcome the granulometric drift observed previously. In particular, it has found that a step of diluting the emulsion appreciably and very advantageously improves the stability of the particle size of said emulsion: concretely, the average particle diameter hardly changes over time, over periods that can reach 4 hours. This improvement was the subject of the filing of the application WO2014 / 053788A1 .

1. 1) une unité de stockage d'une solution aqueuse de matière cationique,
2. 2) une unité de mélange d'ASA et de solution aqueuse de matière amylacée cationique, connectée avec l'unité 1),
3. 3) une unité d'émulsification du mélange d'ASA et de la solution aqueuse de matière amylacée cationique, connecté avec l'unité 2), et exempte de boucle de recirculation.

In the document WO2013 / 186491 or in the document WO2014 / 053788A1 the process for producing an ASA emulsion in an aqueous solution of cationic starch material is carried out in an installation comprising:

1. 1) a storage unit for an aqueous solution of cationic material,
2. 2) a mixing unit of ASA and an aqueous solution of cationic starchy material, connected with the unit 1),
3. 3) an emulsification unit of the mixture of ASA and the aqueous solution of cationic starchy material, connected with the unit 2), and free of recirculation loop.

These three units 1), 2) and 3) make it possible to obtain an emulsion of alkenyl succinic anhydride (ASA) in an aqueous solution of cationic starchy material as taught by the application. WO 2013/186491 , having a maximum of particles whose diameter is centered on an optimum size that the skilled person estimates between 1 micron and 1.5 microns.

The device of the document WO2014 / 053788A1 further comprises a dilution unit of the emulsion connected to the emulsification unit 3) and which makes it possible to dilute the emulsion, and thus to stabilize the particle size of the emulsion.

In the document WO2013 / 186491 or the document WO2014 / 053788A1 , the Applicant has identified two devices ("emulsification unit") for producing the emulsion from the mixture of ASA and the aqueous solution of cationic starchy material, preferably without recirculation of the emulsion to the device. These are Process Pilot DR 2000/4 (IKA ®) or Ytron Z (YTRON ®) materials.

Industrial scale test:

Wishing to confirm the relevance of this manufacturing process on an industrial scale, the Applicant has carried out continuous manufacturing trials of an alkenyl succinic anhydride (ASA) emulsion in an aqueous solution of cationic starchy material, by means of an emulsification unit, and according to production rates adapted to the needs of paper machines.

To do this, the Applicant has used Ytron Z material (YTRON ®), the only emulsifier device among the two identified suitable for this industrial application, online.

This test was carried out on an industrial scale for an uninterrupted duration of 27 hours, under the following conditions, substantially similar to that of example 2 of the document FR1259423 .

An aqueous solution of cationic starchy material marketed by ROQUETTE® under the name VECTOR® SCA 2015 is used. ASA, which is the Chemsize® A180 product marketed by CHEMEC®, is also used.

The water supply is from an existing distribution network. Transfers and dosing of the ASA and the aqueous solution of cationic starchy material to the emulsification unit, are made from their container, by means of pipe and positive displacement pumps, whose rotation speeds are controlled by the instructions desired flow rate and the target cationic starch content (dry) / ASA.

In this case, and in this test, the dry weight ratio cationic starchy material / ASA is 0.3.

Prior to the mixing of "ASA / aqueous solution of cationic starchy material", the aqueous solution marketed under the name VECTOR® SCA 2015 is diluted in line so as to obtain an aqueous solution of starchy material whose dry matter content is 8% of its total weight.

This aqueous solution of starchy material, with a dry matter content of 8%, is mixed in line with the ASA at the mixing unit 2). This mixture " aqueous solution of starchy material / ASA " is then conveyed via a pipe to the emulsification unit 3).

This is Ytron Z material (YTRON ®), previously identified, free of recirculation loop.

This device comprises a housing, whose internal volume forms a substantially cylindrical emulsification chamber, and a single rotor / stator torque. Each rotor and each stator have three rows of concentric toothed rings: the stator and rotor rings are mutually entangled in order to allow shearing of the toothed rings during rotation of the rotor. During this test, the speed of rotation of the rotor is adjusted so as to obtain a peripheral speed of the rotor, at the level of the toothed crowns, of the order of 31 m / s.

The fluid flow rate to the emulsification unit is about 50 l / h.

The casing of the emulsification unit comprises a single inlet, with a diameter of the order of 2-3 cm for the "aqueous starch solution / ASA" mixture to be homogenized, and located substantially in the axis of the rotor, and a single outlet for the directional emulsion substantially tangential to the cylindrical chamber.

At the outlet of the emulsification unit, an emulsion is obtained, the particle size distribution of which is centered on a gap between 1 μm and 1.5 μm. The peak of the curve is measured at 1.25 microns analyzed from a laser granulometer marketed by MALVERN® under the name Mastersizer® and under the conditions specified below for the examples.

The emulsion is then diluted in line by a factor of 2, ie a diluted emulsion flow rate of about 90-100 l / h.

A diluted emulsion is obtained, the particle size distribution of which is narrow and centered over a range of between 1 μm and 1.5 μm. We speak of "narrow" particle size distribution, when at least 80% by volume of said particles will have a diameter of less than 2 μm, and when the average diameter is comprised in 1 μm and 1.5 μm.
As taught by the document WO2014 / 053788 A1 the stability of the particle size of the emulsion is improved compared to an undiluted emulsion.

The results are thus satisfactory with regard to the quality of the emulsion and in particular the distribution of the particle size distribution. The use of the emulsion as a sizing composition gives satisfactory performance in terms of hydrophobicity of the paper.

• La figure 1 illustre un diagramme schématique du test réalisé accompagné de photos des encrassements au couple rotor/stator, ainsi qu'à la sortie de l'unité d'émulsification 3).
• La figure 2 représente deux photos de détail de l'encrassement au niveau de l'entrée de l'unité d'émulsification,
• La figure 3 est une photo de détail de l'encrassement au niveau de la sortie de l'unité d'émulsification 3).

On the other hand, and unexpectedly, this test on an industrial scale revealed the production of deposit in a very large quantity, only after one day of production, fouling which went as far as to clog and cut off the power supply. emulsion of the paper machine.

• The figure 1 illustrates a schematic diagram of the test carried out accompanied by photos of the fouling at the rotor / stator pair, as well as at the exit of the emulsification unit 3).
• The figure 2 represents two detailed photos of the fouling at the inlet of the emulsification unit,
• The figure 3 is a detail photo of the fouling at the outlet of the emulsification unit 3).

In conclusion the installation tested, and as taught in the document WO2013 / 186491 or WO2014 / 053788A1 causes unacceptable fouling problems on an industrial scale, only after one day of production and for flow rates compatible with paper machines.

The method of manufacturing an emulsion, according to the invention, aims to overcome the fouling problems identified above.

This method makes it possible to produce an emulsion whose particle size distribution is narrow and centered over an interval of between 1 μm and 1.5 μm, without substantial rise in temperature of the emulsion, a phenomenon which accelerates hydrolysis of ASA.

The manufacturing method according to the invention optionally allows, according to one embodiment, obtaining such an emulsion whose particle size is stabilized compared to an undiluted emulsion.

• a) réaliser une solution aqueuse de matière amylacée cationique dont la teneur en matière sèche est comprise entre 7% et 12% de son poids total,
• b) conduire de manière séparée l'ASA et la solution aqueuse de matière amylacée cationique issue de l'étape a) et alimenter la chambre d'émulsification en ASA et en la solution aqueuse de matière amylacée cationique issue de l'étape a), respectivement grâce à deux entrées de fluides distinctes, de manière à ne pas les mélanger avant leur introduction dans la chambre d'émulsification,
• c) mélanger l'ASA et la solution aqueuse de matière amylacée cationique issue de l'étape a), dans la chambre d'émulsification, de manière à obtenir un ratio en poids sec matière amylacée cationique/ASA inférieur à 1, préférentiellement compris entre 0,2 et 0,6 et très préférentiellement entre 0,25 et 0,5,
• d) réaliser en un seul passage dans l'unité d'émulsification une émulsion à partir du mélange de l'étape c), et ce, sans boucle de recirculation,
• e) diluer l'émulsion issue de l'étape d) à proximité immédiate la sortie de l'unité d'émulsification, d'axe tangentiel à la périphérie du rotor, le diamètre de la sortie de la chambre d'émulsification étant compris entre 3 mm et 10 mm, l'étape de dilution étant réalisée en aval de la sortie d'unité d'émulsification, en acheminant l'émulsion non diluée selon une trajectoire rectiligne, depuis la sortie de l'unité d'émulsification, et jusqu'à l'endroit de la dilution, sans changement de direction, au moyen d'un dispositif de dilution comprenant une section droite de tuyau dont l'extrémité proximale est connectée à la sortie de l'unité d'émulsification et dont l'extrémité distale débouche dans un coude d'un tuyau de plus grand diamètre et canalisant le liquide de dilution,

et dans lequel le facteur de dilution de l'étape e) est compris entre 4 et 21 de manière à obtenir une vitesse minimale du fluide dans un tuyau en aval au dispositif de dilution, supérieure à 0.2 m/s.Also a first object of the present invention consists in a process for continuously manufacturing an emulsion of ASA in an aqueous solution of cationic starch material implemented by means of an emulsification unit comprising an emulsification chamber receiving a rotor / stator pair, the method comprising the following steps:

• a) producing an aqueous solution of cationic starchy material whose solids content is between 7% and 12% of its total weight,
• b) separately conducting the ASA and the aqueous solution of cationic starchy material resulting from step a) and supplying the emulsification chamber with ASA and with the aqueous solution of cationic starchy material resulting from step a), respectively by two separate fluid inlets, so as not to mix them before their introduction into the emulsification chamber,
• c) mixing the ASA and the aqueous solution of cationic starchy material resulting from step a), in the emulsification chamber, so as to obtain a dry weight ratio cationic starchy material / ASA of less than 1, preferably between 0.2 and 0.6 and very preferably between 0.25 and 0.5,
• d) producing in a single pass in the emulsification unit an emulsion from the mixture of step c), without a recirculation loop,
• e) diluting the emulsion resulting from step d) in the immediate vicinity of the outlet of the emulsification unit, of axis tangential to the periphery of the rotor, the diameter of the outlet of the emulsification chamber being between 3 mm and 10 mm, the dilution step being carried out downstream of the emulsification unit outlet, by conveying the undiluted emulsion along a straight path from the outlet of the emulsification unit, and up to at the dilution site, without a change in direction, by means of a dilution device comprising a cross-section of pipe whose proximal end is connected to the outlet of the emulsification unit and whose end distal discharge into a bend of a larger diameter pipe and channeling the dilution liquid,

and wherein the dilution factor of step e) is between 4 and 21 so as to obtain a minimum fluid velocity in a pipe downstream of the dilution device, greater than 0.2 m / s.

• une unité d'émulsification comprenant une chambre d'émulsification recevant un couple rotor/stator, exempte d'une boucle de recirculation,
• des pompes volumétriques et des tuyaux, destinés à conduire respectivement l'ASA et une solution aqueuse de matière amylacée cationique selon un ratio de débits déterminé, lesdits tuyaux étant séparés et distincts et aptes à alimenter la chambre d'émulsification en ASA et en la solution aqueuse de matière amylacée, respectivement grâce à deux entrées de fluides, distinctes, de manière à ne pas les mélanger avant leur introduction dans la chambre d'émulsification,
• un dispositif de dilution en continu connecté à la sortie de l'unité d'émulsification, d'axe tangentiel à la périphérie du rotor, le diamètre de la sortie de la chambre d'émulsification étant compris entre 3 mm et 10 mm, ledit dispositif de dilution comprenant une section droite de tuyau dont l'extrémité proximale est connectée à la sortie de l'unité d'émulsification et dont l'extrémité distale débouche dans un coude d'un tuyau de plus grand diamètre destiné à canaliser le liquide de dilution et de manière à permettre l'acheminement de l'émulsion non diluée selon une trajectoire rectiligne, depuis la sortie de l'unité d'émulsification, jusqu'à l'endroit de la dilution, sans changement de direction.

The invention also relates to an installation suitable for the continuous manufacture of an ASA emulsion in an aqueous solution of cationic starchy material, comprising:

• an emulsification unit comprising an emulsification chamber receiving a rotor / stator torque, free of a recirculation loop,
• volumetric pumps and pipes, intended respectively to conduct the ASA and an aqueous solution of cationic starchy material according to a determined flow rate ratio, said pipes being separate and distinct and able to supply the emulsification chamber with ASA and with the solution aqueous starch material, respectively through two separate fluid inlets, so as not to mix before introduction into the emulsification chamber,
• a continuous dilution device connected to the output of the emulsification unit, having an axis tangential to the periphery of the rotor, the diameter of the outlet of the emulsification chamber being between 3 mm and 10 mm, said device dilution device comprising a straight section of pipe whose proximal end is connected to the outlet of the emulsification unit and whose distal end opens into a bend of a larger diameter pipe for channeling the dilution liquid and so as to allow the delivery of the undiluted emulsion along a straight path from the exit of the emulsification unit to the point of dilution, without a change of direction.

The invention also relates to an assembly comprising a paper machine and an installation for continuously manufacturing an ASA emulsion in an aqueous solution of cationic starchy material according to the invention and connected to the paper machine.

1. a) on obtient une émulsion d'anhydride alkényle succinique, dite ASA dans une solution aqueuse de matière amylacée cationique par la mise en oeuvre du procédé selon l'invention
2. b) on utilise une composition de collage contenant une émulsion fabriquée à l'étape a) dans une opération de collage d'une feuille de papier ou de carton.

The invention also relates to a method of bonding a sheet of paper or cardboard in which:

1. a) an alkenyl succinic anhydride emulsion, called ASA, is obtained in an aqueous solution of cationic starchy material by carrying out the process according to the invention
2. b) using a gluing composition containing an emulsion made in step a) in a gluing operation of a sheet of paper or cardboard.

• La figure 4 est une vue schématique du procédé conforme à l'invention, selon un mode de réalisation,
• La figure 5 est une vue de l'unité d'émulsification de l'installation conforme à l'invention, présentant trois entrées distinctes, respectivement pour l'ASA et la solution aqueuse de matière cationique amylacée, ainsi que pour l'introduction d'une solution de lavage, l'unité d'émulsification étant suivie du dispositif de dilution,
• La figure 6 est une vue éclatée de l'ensemble unité d'émulsification/dispositif de dilution illustré à la figure 5,
• Les figures 7a, 7b et 7c sont respectivement des vues de perspective avant, de coupe et de perspective arrière d'un couple rotor/stator qui peut être utilisé dans le procédé conforme à l'invention, mais qui est connu en tant que tel de l'état de la technique,
• Les figures 8a, 8b et 8c sont respectivement des vues de perspective avant, de coupe et de perspective arrière d'un couple rotor/stator conforme à l'invention, faisant l'objet d'un perfectionnement,
• La figure 9a est une vue schématique de coupe d'une unité d'émulsification du type Ytron Z (YTRON ®) telle que connue de l'état de la technique et qui présente une entrée unique pour le mélange à émulsionner,
• La figure 9b est une vue de coupe de l'unité d'émulsification conforme à l'invention, équipée du couple rotor/stator perfectionné, l'unité présentant deux entrées, distinctes, pour l'ASA et la solution aqueuse de matière amylacée cationique, d'axes inclinés par rapport à l'axe du rotor (l'entrée pour la solution de lavage est non représentée sur cette figure).
• La figure 10 est une vue d'une installation de fabrication d'une émulsion comprenant deux unités d'émulsification, en parallèle.

The invention will be better understood on reading the following description accompanied by the appended drawings among which:

• The figure 4 is a schematic view of the method according to the invention, according to one embodiment,
• The figure 5 is a view of the emulsification unit of the plant according to the invention, having three separate entries, respectively for the ASA and the aqueous solution of starch cationic material, as well as for the introduction of a solution of washing, the emulsification unit being followed by the dilution device,
• The figure 6 is an exploded view of the emulsification unit / dilution device assembly shown in FIG. figure 5 ,
• The Figures 7a, 7b and 7c are respectively front perspective views, sectional views and rear perspective of a rotor / stator torque that can be used in the process according to the invention, but which is known as such from the state of the art,
• The Figures 8a, 8b and 8c are respectively front perspective views, section and rear perspective of a rotor / stator torque according to the invention, being improved,
• The figure 9a is a schematic sectional view of an emulsification unit of the Ytron Z type (YTRON®) as known from the state of the art and which has a single entry for the mixture to be emulsified,
• The figure 9b is a sectional view of the emulsification unit according to the invention, equipped with the improved rotor / stator torque, the unit having two separate inputs for the ASA and the aqueous solution of cationic starchy material, axes inclined relative to the axis of the rotor (the entry for the washing solution is not shown in this figure).
• The figure 10 is a view of an emulsion manufacturing plant comprising two emulsification units, in parallel.

The invention arose from the finding by the inventors that one of the causes of fouling results, according to the state of the art known from the document WO2013 / 186491 pre-mixing, upstream of the emulsification unit, of the ASA with the aqueous solution of cationic starchy material.

Also, and according to one characteristic of the invention (ie step b), the ASA and the aqueous solution of cationic starchy material are not mixed before being introduced into the emulsification chamber 2. In other words, and according to In the invention, the mixing of these two components is carried out directly in the emulsification chamber 2, and not in an upstream mixer, distinct from the emulsification unit as taught by the document. WO 2013/186491 .

For this purpose, the emulsification unit 1 has two separate inputs E1, E2 for the ASA and the aqueous solution of cationic starchy material and separate pipes for conveying these two fluids.

According to an embodiment illustrated in figure 9 these two inputs E1, E2 may advantageously be axes inclined relative to the axis A of the rotor 3 in such a way that their jets intersect in the emulsification chamber 2.

Step a) of producing the aqueous solution of cationic starchy material either consists in providing an aqueous solution of cationic starchy material, as commercially available, or else in diluting it with water, in order to obtain the desired dry matter content. This dilution can be performed online, in the installation, for example by means of a static mixer. The dilution water is preferably between 5 ° C and 40 ° C, and more preferably between 5 ° C and 25 ° C.

For all intents and purposes, it is specified that the term "cationic starchy material" designates a starchy material obtained by any of the known methods of cationisation in aqueous medium, in a solvent medium or in a dry phase, since this process allows one or more a plurality of nitrogen group (s) of electropositive nature to be attached to said starchy material. We can refer to the document WO 2005/014709 A1 .

By way of examples of aqueous solution of cationic starchy materials that can be used according to the present invention, mention may be made of the products marketed under the VECTOR® SC and IC (ROQUETTE®) range, Raisabond® 15 (CHEMIGATE), Licocat® P (SUEDSTAERKE®), Lyckeby® LP 2145 and LP 1140 (LYCKEBY®), Redisize® 205 and Redibond® 4000 (NATIONAL STARCH®) and Raifix® 25035 and 01035 (CIBA RAISIO®).

Step c) consists, directly in the emulsification chamber 2, of mixing between the aqueous solution of cationic starchy material from step a) and the ASA. The ratio in dry weight cationic starchy material / ASA is less than 1, preferably between 0.2 and 0.6, and very preferably between 0.25 and 0.5.

For this purpose, the manufacturing plant comprises volumetric pumps (not shown) and pipes, intended respectively to conduct the ASA and an aqueous solution of cationic starchy material in a ratio of flow rates determined in order to obtain the ratio by weight dry cationic starchy material / ASA.

Step d) consists of circulating in a single pass the mixture which has been obtained in stage c), in the emulsification unit 1. This unit comprises the emulsification chamber 2 receiving the rotor torque 3 / stator 4.

The rotor 3 and the stator 4 preferably each have concentric toothed rings, the stator and rotor rings being mutually entangled. Preferably each rotor and each stator have several rows of concentric toothed rings, for example three in number, as illustrated in the examples of the figures.

In order to limit the heating, the emulsification unit preferably comprises a single rotor / stator torque 4. According to another alternative (not shown), the emulsification unit may comprise several successive stages ( ie 3 stages) each having a rotor / stator torque.

According to the method, the rotor 3 of the emulsification unit is preferably rotated in order to obtain a peripheral speed of the rotor, in particular at the toothed crowns, of between 30 m / s and 40 m / s.

Finally, the dilution step e) is carried out in the immediate vicinity of the outlet So of the emulsification unit 1, and not just upstream of the paper machine. The emulsion is preferably diluted with water.
This dilution step firstly makes it possible to cool the emulsion at the outlet of the emulsification unit 1, and thus to avoid the hydrolysis of the ASA. This dilution makes it possible to reduce the deposits in the pipe downstream of the dilution device, carrying the emulsion diluted from the manufacturing facility to the paper machine, substantially increasing the flow of fluid in the pipe.

Thus, a minimum fluid velocity in this downstream pipe is sought, greater than 0.2 m / s, preferably greater than 0.8 m / s, or even greater than or equal to 1 m / s.

In this regard, and to satisfy these speeds and thus the objective of limiting the deposits in the pipe, it is necessary to dilute the emulsion by a dilution factor of between 4 and 21, and even more preferably between 5 and 15, very preferably between 6 and 11.
Such a dilution of a factor strictly greater than 3.5 may be necessary, in particular when the fluid flow rate is between 45 l / h and 300 l / h in the emulsification unit 1, for the purpose of to reach such fluid velocities in the pipes.

This dilution factor is greater than that taught in the application WO2014 / 053788A1 , of the Applicant. If necessary and for high dilutions, close to the upper limit (ie dilution factor of 21), this high dilution can be to the detriment of the stability over time of the emulsion. A dilution factor of between 4 and 11 may be a good compromise between the stability of the emulsion and the objective of limiting the fouling.

In order to limit the deposits between the emulsification chamber 2 and the dilution site of step e), the fluid outlet So of the emulsification chamber 2 is of axis tangential to the rotor 3 and is reduced diameter, between 3 mm and 10 mm, such as for example 4 mm, 6 mm or 8 mm: an output diameter of less than or equal to 10 mm is chosen, much smaller than the output diameter of the commercial version Ytron Z ( YTRON ®)., To limit deposits in this area.

In the case of variable flow rates during the manufacturing process, the emulsification unit may comprise a set of tips 7, removable, to allow the diameter change of the So output. Each tip 7 has a clean inner diameter (ie 4 mm, 6 mm or 8 mm). Depending on the needs and the operating flows, the diameter change of the output So is obtained simply by the removal of a tip 7 and its replacing, for example in a housing of the cylindrical wall 6 of the housing, by another tip diameter of more suitable.

For these same reasons of adaptability, the emulsification unit 1 may comprise a set of rotor / stator pairs, distinct, and differentiated by the length of the teeth of the concentric ring gear.

For example, and for a fluid flow rate of between 45 l / h and 150 l / h at the emulsification unit 1, it is possible to choose a stator 4 and a rotor 3, the length of the teeth of the toothed crowns being between 4 mm and 6 mm and the difference between teeth is between 1 mm and 2 mm. This rotor / stator torque is hereinafter referred to as short-rotor rotor / stator torque.

For a fluid flow rate of between 150 l / h and 300 l / h at the emulsification unit 1, it is possible to choose a stator 4 and a rotor 3 whose length of the teeth of the ring gear is between 9 mm and 12 mm. and whose gap between teeth is between 1 mm and 2 mm. This rotor / stator torque is hereinafter referred to as rotor / long-tooth stator torque.

In order to limit the deposits between the outlet So of the emulsification chamber 2 and the dilution step e), the dilution downstream of the outlet So of the emulsification unit 1 is carried out by means of a control device. dilution 8 preferably comprising a straight section 80 of pipe whose proximal end is connected to the outlet So of the emulsification unit 1 and whose distal end opens into a bend 81 of a pipe of larger diameter, channeling the dilution liquid.

The undiluted emulsion is thus conveyed in a rectilinear path, from the outlet So of the emulsification unit 1 and up to the place of dilution, without change of direction and thus without elbow likely to promote deposits. Such a dilution device 8 operates by venturi effect.

The Applicant has also worked on the geometry of the emulsification chamber, for the same purpose of deposit limitation. In this regard, Figures 7a, 7b and 7c illustrate a rotor / stator torque, as known from the state of the art, as such. For such rotor / stator torque, the free internal volume of the emulsification chamber 2, upstream of the shear work (depending on the direction of flow) is defined between the walls of the cover and the rotor / stator assembly. As visible at the cut view of the figure 9a which represents an emulsification unit according to the state of the art Ytron Z (YTRON®) with a single input Em, and because of the geometry of the stator S, it is understood that this free internal volume is large and extends radially to beyond the diameter of the toothed rings of stator S and rotor R.

As represented in figure 9b , downstream of the shear work, according to the direction of flow, the free volume of the emulsification chamber 2 is defined between the rotor 3, the inner surface of the cylindrical wall 6 of the housing, and a cover 5 'of the housing (opposite the cover 5 carrying the inputs E1, E2).

The new rotor / stator torque illustrated in Figures 8a, 8b and 8c is intended to significantly reduce this free volume of the emulsification chamber, upstream shear work between the toothed crowns. The stator 4 is always positioned between the rotor 3 and said fluid inlets E1, E2 in said emulsification chamber 2.

As represented in figure 9b , the stator geometry thus modified comprises a reduced central opening 40, of smaller diameter than the average diameter of the toothed crowns and a wall 41 extending from the central opening 40 and up to the stator toothed crowns 4, flaring. This reduced central opening 40 is intended to be traversed by the jets of the fluid inlets E1, E2.

As visible at the cut view of the figure 9b this new geometry of the stator 4 substantially reduces the free internal volume of the emulsification chamber 2, upstream of shear work, and thus the deposition surfaces. We thus notice the figure 9b that this free internal volume, upstream, is defined between the flared wall 41 and the rotor 3, and is thus contained with a diameter smaller than the diameter of the toothed rings of the stator 4.

The emulsification unit 1 may comprise a third fluid inlet, marked En, distinct from the inputs E1 and E2, and allowing the implementation of a cleaning cycle of the emulsification unit 1, or even the dilution device 8 located downstream of the emulsification unit.

The cleaning is carried out by feeding the inlet En of a cleaning fluid such as water, with or without adjuvant, and preferably by rotating the rotor.

In order not to stop the paper machine during the maintenance and cleaning periods of the emulsification unit, the emulsion manufacturing plant can advantageously comprise, as illustrated in FIG. figure 10 , two emulsification units 1, 1 ", the emulsion being produced from the same source of ASA and the same solution of cationic starch material, to one of the two emulsification units 1.1 while the other emulsification unit implements a cleaning cycle, or undergoes maintenance.

The electrovalve marked 9 is a three-way solenoid valve which makes it possible to conduct the cationic solution of starchy material, either at the inlet E2 of the first emulsification unit 1, or at the inlet E2 "of the second emulsification unit 1 ". The solenoid valve marked 10, is a three-way solenoid valve for driving the ASA, either at the inlet E1 of the first emulsification unit 1, or at the inlet E1 "of the second emulsification unit 1" .

In operation, these two solenoid valves 9 and 10 conduct the ASA and the cationic starch solution either at the inputs of the first emulsification unit 1, or at the inputs of the second emulsification unit 1 ".

The electrovalve marked 11 is a three-way solenoid valve which makes it possible to drive the diluted emulsion resulting from step e) to the paper machine via a pipe, or from the outlet of the dilution device 8 associated with the first emulsification unit 1, or from the output of the dilution device 8 "associated with the second emulsification unit 1".

An automaton makes it possible to control these three solenoid valves 9, 10 and 11 and to synchronize them in order to connect either the first emulsification unit 1 or the second emulsification unit 1 ".

The process according to the present invention is also characterized in that the ASA is a product preferably of synthetic origin; these are modified oils that result from C16-C18 cuts. Among the ASAs commercially available and usable in the present invention, mention may be made of the product Chemsize® A 180 (CHEMEC®) or the product PENTASIZE® 8A by the company PENTAGON® which is an equivalent product.

This process is also characterized in that the aqueous solution of cationic starchy material has a fixed nitrogen content of less than 3.5%, preferably between 0.3% and 3.5%, very preferably between 0.7% and 2% by dry weight of nitrogen relative to the total weight of cationic starchy material.

This cationic starchy material may optionally be modified from an operation chosen from hydrolysis, chemical and physical, mechanical, thermomechanical or even thermal transformations. A hydrolysis operation, very directly aimed at reducing the molecular weight and, in most cases, reducing the viscosity, can be conducted by various means such as chemical, commonly by the action of an acid, a base or an oxidizing agent or by an enzymatic action, most commonly by amylase. The common chemical modifications are of different types such as oxidation, especially with hypochlorite, esterification, such as acetylation, etherification, for example by cationization, carboxymethylation or hydroxypropylation. Physical treatments may be practiced by thermomechanical means, such as extrusion or pre-gelatinization, or thermal, such as those known to those skilled in the art as Hot Moisture Treatment (HMT) or Annealing .

The following examples make it possible to better appreciate the nature of the present invention, without however limiting its scope.

EXAMPLES

• 800 ml d'eau déminéralisée
• Agitation 1900 tours/min
• Mesure background : 10 s
• 3 mesures consécutives par échantillon (délai entre mesures : 0 s)
• Durée de chaque mesure : 10 s
• Obscuration Laser : entre 8% et 13%
• Indice de réfraction : 1,5
• Dispersant (eau) indice de réfraction : 1,33
• Absorption : 0,01
• Modèle de forme de particules = sphérique

In the tests, the particle size of the emulsions is analyzed from a laser granulometer marketed by MALVERN® under the name Mastersizer®, with the following parameters:

• 800 ml of demineralized water
• Agitation 1900 rpm
• Measure background: 10 s
• 3 consecutive measurements per sample (time between measurements: 0 s)
• Duration of each measurement: 10 s
• Laser Obscuration: between 8% and 13%
• Refractive index: 1.5
• Dispersant (water) refractive index: 1.33
• Absorption: 0.01
• Particle shape model = spherical

Test No. 1 on an industrial scale (Reference):

The first test, of reference, is that which made it possible to note the problem of fouling, already here described in the introduction, and illustrated schematically in the figure 1 .

This is carried out continuously over a period of 27 hours, under the following conditions, substantially similar to those of example 2 of the document FR1259423 .

An aqueous solution of cationic starchy material marketed by ROQUETTE® under the name VECTOR® SCA 2015 is used. ASA, which is the Chemsize® A180 product marketed by CHEMEC®, is also used.

The water supply is from an existing distribution network. The transfers and dosing of the ASA and the aqueous solution of cationic starchy material to the emulsification unit, are, from their container, by means of pipe and pumps volumetric, whose rotational speeds are slaved to the desired flow rates and the target ratio cationic starchy material (dry) / ASA.

The dry weight ratio cationic starchy material / ASA is 0.3.

Prior to the mixing of "ASA / aqueous solution of cationic starchy material", the aqueous solution marketed under the name VECTOR® SCA 2015 is diluted in line so as to obtain an aqueous solution of starchy material whose dry matter content is 8% of its total weight.

This aqueous solution of starchy material, with a solids content of 8%, is mixed in line with the ASA in a mixing unit. This mixture " aqueous solution of starchy material / ASA" is then conveyed via a pipe to the emulsification unit.

This is Ytron Z material (YTRON ®), previously identified, free of recirculation loop.

This device comprises a housing, whose internal volume forms a substantially cylindrical emulsification chamber, and a single rotor / stator torque. Each rotor and stator have three rows of concentric ring gear: the stator and rotor rings are mutually entangled to allow shearing. During this test, the speed of rotation of the rotor is adjusted so as to obtain a peripheral speed of the rotor, at the level of the toothed crowns, of the order of 31 m / s.

The fluid flow rate to the emulsification unit is about 50 l / h.

The casing of the emulsification unit comprises a single inlet of diameter of the order of 3-4 cm for the mixture "aqueous solution of starchy material / ASA" to be homogenized, located substantially in the axis of the rotor, and a single outlet for the directional emulsion substantially tangential to the cylindrical chamber and of diameter of the order of 2-3 cm.

The emulsion is then diluted in line by a factor of 2, ie a diluted emulsion flow rate of approximately 100 l / h. The temperature of the diluted water is 38 ° C.

At the outlet of the emulsification unit, an emulsion is obtained, the particle size distribution of which is narrow and centered on a gap between 1 μm and 1.5 μm. The peak of the curve (particle volume in% / diameter in μm) measured by the granulometer is 1.25 μm.

• le tuyau d'alimentation de l'unité d'émulsification,
• l'entrée de l'unité d'émulsification de l'ASA et la solution de matière amylacée cationique, telle qu'illustrée à la figure 2,
• la chambre d'émulsion et notamment sur le rotor, tel qu'illustré à la figure 1 (visible sur la photo à gauche),
• la sortie de l'unité d'émulsification telle qu'illustrée à la figure 1 (visible sur la photo au centre) et à la figure 3,
• le tuyau en aval du dispositif effectuant la dilution et acheminant l'émulsion diluée jusqu'à la machine à papier, tel qu'illustré à figure 1 (visible sur la photo à droite).

After a day of production, however, there is significant fouling in:

• the feed pipe of the emulsification unit,
• the entry of the ASA emulsification unit and the cationic starch solution, as shown in FIG. figure 2 ,
• the emulsion chamber and especially on the rotor, as illustrated in FIG. figure 1 (visible in the picture on the left),
• the output of the emulsification unit as illustrated in figure 1 (visible in the center photo) and at the figure 3 ,
• the pipe downstream of the device performing the dilution and conveying the diluted emulsion to the paper machine, as illustrated in FIG. figure 1 (visible on the photo on the right).

Test No. 2 on an industrial scale (Invention):

In order to overcome these fouling problems, modifications have been made to the manufacturing process and to the installation that makes it possible to implement it.

A first substantial modification consists, according to steps b) and c) of the process according to the invention, to mix the ASA and the amylaceous cationic solution resulting from step a) directly in the emulsification chamber of the unit emulsification, and not in an upstream mixing unit. The modified plant thus comprises separate pipes and separate entrances for the ASA and the starch cationic material solution.

A second substantial change is, according to step e) of the process to further dilute the emulsion, in order to increase the velocity of fluid in the pipe downstream of the dilution device. In this test, the dilution factor goes from 2 to 6.

In addition, an outlet is used for the emulsification unit of smaller diameter (8 mm) and a dilution device 8 as previously described.

A rotor / stator torque with short teeth as defined above is used.

The products used are the same as for test No. 1: an aqueous solution of cationic starchy material marketed by ROQUETTE® under the name VECTOR® SCA 2015 is used. ASA is also used. which is the Chemsize® A180 product marketed by CHEMEC®.

• teneur en matière sèche de la solution aqueuse de matière amylacée cationique, selon l'étape a) du procédé : 8%
• ratio en poids sec matière amylacée cationique/ASA, selon l'étape c) du procédé : 0,25
• débit dans l'unité d'émulsification : 49,5 l/h
• facteur de dilution selon l'étape e) du procédé : 6 (5 x le volume de l'émulsion),
• vitesse périphérique du rotor : environ 31 m/s (4600 tr/min),
• température émulsion diluée : 29°C

Thus, the conditions of this test n ° 2 are as follows:

• dry matter content of the aqueous solution of cationic starchy material, according to step a) of the process: 8%
• ratio by dry weight cationic starchy material / ASA, according to step c) of the process: 0.25
• flow rate in the emulsification unit: 49.5 l / h
• dilution factor according to step e) of the process: 6 (5 × the volume of the emulsion),
• rotor peripheral speed: approximately 31 m / s (4600 rpm),
• diluted emulsion temperature: 29 ° C.

• pas d'encrassement au niveau des tuyaux d'alimentation et des entrées de l'unité d'émulsification,
• pas d'encrassement au niveau de la chambre d'émulsification,
• pas d'encrassement au niveau de la sortie de l'unité d'émulsification,
• pas d'encrassement après l'étape de dilution de l'étape e), dans le tuyau en aval.

After the modifications made, there is a very marked improvement in terms of fouling, after one day of production, namely:

• no clogging at the feed pipes and the emulsification unit inlets,
• no fouling at the emulsification chamber,
• no clogging at the outlet of the emulsification unit,
• no fouling after the dilution step of step e) in the pipe downstream.

A diluted emulsion sample is taken: the peak of the particle distribution curve (volume of particles in% / diameter in μm) measured by the particle size analyzer is 1.30 μm.

Test No. 3 on an industrial scale (Invention):

The conditions of Test No. 3 differ from those of Test No. 2 by the flow rate to the emulsion unit of 190 l / h, as well as by the dry weight ratio cationic starch material / ASA. which is slightly different, equal to 0.3.

The installation is the modified one of test n ° 2: one replaces the rotor / stator torque with "short teeth" by a rotor / stator with "long teeth".

• teneur en matière sèche de la solution aqueuse de matière amylacée cationique, selon l'étape a) du procédé : 8%
• ratio en poids sec matière amylacée cationique/ASA, selon l'étape c) du procédé : 0,3
• débit dans l'unité d'émulsification : 190 l/h
• facteur de dilution selon l'étape e) du procédé : 6 (5 x le volume de l'émulsion),
• vitesse périphérique du rotor : environ 31 m/s (4600 tr/min)
• température émulsion diluée : 24°C

The conditions of this test n ° 3 are as follows:

• dry matter content of the aqueous solution of cationic starchy material, according to step a) of the process: 8%
• ratio by dry weight cationic starchy material / ASA, according to step c) of the process: 0.3
• flow rate in the emulsification unit: 190 l / h
• dilution factor according to step e) of the process: 6 (5 × the volume of the emulsion),
• rotor peripheral speed: approximately 31 m / s (4600 rpm)
• diluted emulsion temperature: 24 ° C.

As for Test No. 2, the fouling problems are solved.

A diluted emulsion sample is taken: the peak of the particle distribution curve (volume of particles in% / diameter in μm) measured by the particle size analyzer is 1.38 μm.

Test No. 4 on an industrial scale (Invention):

The conditions of Test No. 4 differ from those of Test No. 3 only by the flow rate at the emulsification unit which is 300 l / h.

• teneur en matière sèche de la solution aqueuse de matière amylacée cationique, selon l'étape a) du procédé : 8%
• ratio en poids sec matière amylacée cationique/ASA, selon l'étape c) du procédé : 0,3
• débit dans l'unité d'émulsification : 300 l/h
• facteur de dilution selon l'étape e) du procédé : 6 (5 x le volume de l'émulsion)
• vitesse périphérique du rotor : environ 31 m/s (4600 tr/min)
• température émulsion diluée : 26°C

The conditions of this test n ° 4 are as follows:

• dry matter content of the aqueous solution of cationic starchy material, according to step a) of the process: 8%
• ratio by dry weight cationic starchy material / ASA, according to step c) of the process: 0.3
• flow rate in the emulsification unit: 300 l / h
• dilution factor according to step e) of the process: 6 (5 × the volume of the emulsion)
• rotor peripheral speed: approximately 31 m / s (4600 rpm)
• diluted emulsion temperature: 26 ° C.

As for Test No. 2 and Test No. 3, the fouling problems are solved.

A diluted emulsion sample is taken: the peak of the particle size distribution curve (in terms of volume of particles in% / diameter in μm) measured by the particle size analyzer is 1.49 μm.

Test No. 5 on an industrial scale (Invention):

The conditions of Test No. 5 differ from those of Test No. 4 only by the rotor speed of the emulsification unit which is 5700 rpm.

• teneur en matière sèche de la solution aqueuse de matière amylacée cationique, selon l'étape a) du procédé : 8%
• ratio en poids sec matière amylacée cationique/ASA, selon l'étape c) du procédé : 0,3
• débit dans l'unité d'émulsification : 300 l/h
• facteur de dilution selon l'étape e) du procédé : 6 (5 x le volume de l'émulsion)
• vitesse périphérique du rotor : environ 38 m/s (5700 tr/min)
• température émulsion diluée : 21°C.

The conditions of this test n ° 5 are as follows:

• dry matter content of the aqueous solution of cationic starchy material, according to step a) of the process: 8%
• ratio by dry weight cationic starchy material / ASA, according to step c) of the process: 0.3
• flow rate in the emulsification unit: 300 l / h
• dilution factor according to step e) of the process: 6 (5 × the volume of the emulsion)
• rotor peripheral speed: approximately 38 m / s (5700 rpm)
• diluted emulsion temperature: 21 ° C.

As for the tests n ° 2, n ° 3 and n ° 4, the problems of fouling are solved.

A diluted emulsion sample is taken: the peak of the particle size distribution curve (in terms of volume of particles in% / diameter in μm) measured by the particle size analyzer is 1.39 μm.

The three tests n ° 2, 3, 4 and 5, on an industrial scale, confirm the relevance of the manufacturing process of the emulsion. The particle sizes of the emulsions obtained are satisfactory, advantageously free from any harmful hydrolysis phenomena of the ASA, and obtained without the problems of fouling of the installation encountered for the test n ° 1. <b> Table 1 </ b> Test no. 1 2 3 4 5 % dry matter of step a) 8 8 8 8 8 Ratio of step c) 0.3 0.25 0.3 0.3 0.3 Flow rate at the emulsification unit (l / h) 50 49.5 190 300 300 Dilution factor of step e) 2 6 6 6 6 Rotor speed (rpm) 4600 4600 4600 4600 5700 Rotor peripheral speed (m / s) 31 31 31 31 38 Peak distribution curve (μm) 1.25 1.30 1.38 1.49 1.39 Clogging (at 24 hours) Yes no no no no

The results of the various tests on an industrial scale are summarized in Table 1, above. The modifications made it possible to solve the problems of fouling while preserving the qualities of the emulsion, as bonding agent. It should be noted that for these tests on an industrial scale, only one value was tested for the dilution factor (equal to 6). Higher dilutions have not been tested, mainly to avoid the creation of too much volume of effluent to be treated.

However, the Applicant knows that a higher dilution would be even more favorable, with regard to fouling problems in the downstream pipe, conveying the emulsion to the paper machine, in that speeds would be obtained. even larger fluids in this pipe.

The following laboratory tests further demonstrate that a higher dilution, at least up to a dilution factor of 21, does not affect the quality of the emulsion as a tackifier.

Laboratory tests:

In this example, an ASA emulsion is made in an aqueous solution of cationic starchy material in the laboratory and the emulsion is diluted according to three different dilution factors, namely 6, 11 and 21, in order to obtain three diluted emulsions. referred to as "emulsion 1 ", "emulsion 2" and " emulsion 3".

The performance of these three diluted emulsions is then tested as a sizing agent to determine the influence of the dilution factor.

An aqueous solution of cationic starchy material marketed by ROQUETTE® under the name VECTOR® SCA 2015 is used. ASA, which is the Chemsize® A180 product marketed by CHEMEC®, is also used.

The aqueous solution marketed under the name VECTOR® SCA 2015 is diluted so as to obtain an aqueous solution of starchy material whose solids content is 8% of its total weight.

This aqueous solution is mixed with ASA. The dry weight ratio cationic starchy material / ASA is 0.3.

This mixture is then transferred to a device for obtaining an emulsion.

Three samples of this emulsion are diluted with water, respectively in ratios (emulsion / water) of 1/5, 1/10 and 1/20. The diluted emulsion of a ratio 1/5 (of a dilution factor 6) is called " emulsion 1 ". The diluted 1: 10 emulsion (with a dilution factor of 11) is referred to as " emulsion 2 ". The diluted emulsion of a 1/20 ratio (of a dilution factor 21) is called " emulsion 3".

Laboratory sheets of paper are then made from these three emulsions and the degree of hydrophobicity (Cobb 60) is measured.

Concretely, these sheets of laboratory paper called formettes, are manufactured from a FRET device (retention plates) marketed by TECHPAP. Such forms have characteristics close to the industrial customer paper, especially with regard to flocculation and retentions.

The method of manufacturing the formette uses a pulp which is a pulp of virgin fibers (50% resinous, 50% hardwood) with a refining level of 35 ° Schopper (° SR). 35% (by dry weight relative to the total weight of the dough) of natural calcium carbonate marketed by OMYA® under the name of Omyalite®50 is added. The fibrous suspension is loaded at a concentration of 2.5 g / l. 0.3% (dry equivalent / paper) of a HICAT® 5163AM (ROQUETTE®) glue is then added. Three samples of dough are thus taken.

0.35% (based on the paper) of the emulsion 1 is added to the first sample of paste. A first form having a grammage of 70 g / m ^{2 is thus produced} .

0.35% (relative to the paper) of the emulsion 2 is added to the second sample of paste 2. A second form is thus produced with a grammage of 70 g / m ² .

0.35% (relative to the paper) of the emulsion 3 is added to the third sample of paste 3. A third form is thus produced having a grammage of 70 g / m ² .

After manufacturing the sheets, they are placed between 2 blotters and the set is passed twice in a TECHPAP® brand roller press. Each formette is then separated from the blotters and is placed on a TECHPAP® brand dryer, for 5 min at 100 ° C. A ripening of the forms is then carried out, by placing them for 30 minutes in an oven at 110 ° C, to allow the bonding agent to fully give the paper its hydrophobic character. The forms are then placed for a minimum of 24 hours in a room conditioned at 23 ° C (+/- 1 ° C) and 50% relative humidity (+ / 2%) (ISO 187: 1990 and Tappi T402 sp-08 standards). ).

For each form, a measurement of Cobb 60 (ISO standards 535: 1991 and Tappi T441 om-04) is then carried out, which relates to the hydrophobicity of the paper: the lower the quantity of water absorbed, the more hydrophobic the paper is .

Table 2 summarizes the Cobb 60 (g / m ² ) values measured on the forms prepared with these three emulsions. <b> Table 2 </ b> Emulsion N ° Dilution factor Cobb 60 (g / m2) 1 6 20 2 11 20 3 21 18.5

This table demonstrates that a dilution factor of up to 21 does not result in a significant loss of the degree of hydrophobicity.

NOMENCLATURE Invention (Figures 4, 5, 6, 8a, 8b, 8c, 9b and 10):

• 1, 1 "emulsification units,
• 2. Emulsification chamber,
• 3. Rotor,
• 4. Stator,
• 5. Inlet cover (Carter),
• 5 '. Rear cover (Carter),
• 6. Cylinder wall (Carter),
• 7. Removable tip,
• 8, 8 ".Dilution devices,
• 9, 10, 11. Solenoid valves,
• 40. Central opening (Stator 4),
• 41. Flared wall (Stator 4),
• 80. Straight section pipe (Dilution device),
• 81. Elbow (Dilution Device),
• A. Rotor axis,
• E1, E2, E1 ", E2". Separate inputs (emulsification unit),
• In, En. Inlets for cleaning fluid (emulsification unit),
• So. Output (emulsification chamber 2).

State of the art (Figure 9a):

• Em. Mixing inlet,
• R. Rotor,
• S. Stator.

Claims (15)

1. Method of continuously manufacturing an alkenyl succinic anhydride emulsion, hereinafter referred to as ASA, in an aqueous solution of cationic starchy material implemented by means of an emulsification unit (1) comprising an emulsification chamber (2) receiving a couple rotor (3)/stator (4), with the method comprising the steps of:

   - a) providing an aqueous solution of cationic starchy material of which the dry matter content is between 7% and 12% of its total weight,

   - b) conducting separately the ASA and the starchy material aqueous solution from step a) and feeding the emulsifying chamber with ASA and with the starchy material in the aqueous solution from step a), respectively thanks to two separate fluid inlets (E1, E2), in such a way as to not mix them before they are introduced into the emulsification chamber (2),

   - c) mixing the ASA and the aqueous solution of cationic starchy material from step a), in the emulsification chamber (2), in such a way as to obtain a cationic starchy material/ASA dry matter weight ratio less than 1,

   - d) carrying out in a single pass in the emulsification unit (1) an emulsion from the mixture of step c), and this, without a recirculation loop,

   - e) diluting the emulsion from step d), in the immediate vicinity of the outlet (So) of the emulsification unit (1), having an axis tangential to the periphery of the rotor (3), with the diameter of the outlet (So) of the emulsification chamber being between 3 mm and 10 mm, with the step of diluting being carried out downstream of the outlet of the emulsification unit, by conveying the undiluted emulsion according to a straight trajectory, from the outlet (So) of the emulsification unit (1), and to the location of the dilution, without a change in direction, by means of a dilution device (8) comprising a straight section (80) of pipe of which the proximal end is connected to the outlet (So) of the emulsification unit (1) and of which the distal end opens into a bend (81) of a pipe with a larger diameter and which channels the dilution liquid,

   and wherein the dilution factor of the step e) is between 4 and 21 in such a way as to obtain a minimum speed of the fluid in a pipe downstream of the dilution device, greater than 0.2 m/s.
2. Method according to claim 1, wherein the flow rates of ASA and of the aqueous solution of starchy material from the step a) are determined in such a way as to obtain a flow rate of fluid between 45 l/h and 300 l/h in the emulsification unit (1).
3. Method according to claim 1 or 2, wherein the dilution factor of the step e) is between 5 and 15.
4. Method according to one of claims 1 to 3, wherein an emulsification unit having a single couple rotor (3)/stator (4) is chosen for the emulsification unit (1) and wherein, a rotor (3) and a stator (4) is chosen for the couple rotor (3)/stator (4) with each one having concentric gear rims, with the rims of the stator and of the rotor being mutually interlocked.
5. Method according to claim 4 wherein:

   - for a flow rate of fluid between 45 l/h and 150 l/h at the emulsification unit, a stator (4) and a rotor (3) are chosen of which the length of the teeth of the gear rims is between 4 mm and 6 mm and of which the separation between teeth is between 1 mm and 2 mm,

   - for a flow rate of fluid between 150 l/h and 300 l/h at the emulsification unit a stator (4) and a rotor (3) are chosen of which the length of the teeth of the rims is between 9 mm and 12 mm and of which the separation between teeth is between 1 mm and 2 mm.
6. Method according to one of claims 1 to 5, wherein the dilution factor of the step e) is between 4 and 21 in such a way as to obtain a minimum speed of the fluid in the pipe downstream of the dilution device, greater than 1 m/s.
7. Method according to one of claims 1 to 6, wherein the dilution factor of the step e) is between 4 and 11.
8. Installation suitable for the continuous manufacture of alkenyl succinic anhydride emulsion hereinafter referred to as ASA in an aqueous solution of cationic starchy material, comprising:

   - an emulsification unit (1) comprising an emulsification chamber (2) receiving a couple rotor (3)/stator (4), devoid of a recirculation loop,

   - displacement pumps and pipes, intended to respectively convey the ASA and an aqueous solution of cationic starchy material according to a determined ratio of flow rates, with said pipes being separated, able to feed the emulsification chamber with ASA and with an aqueous solution of starchy material, respectively thanks to two separate fluid inlets (E1, E2), in such a way as to not mix them before they are introduced into the emulsification chamber (2),

   - a continuous dilution device (8) connected to the outlet (So) of the emulsification unit (1), with the outlet having an axis tangential to the periphery of the rotor (3), with the diameter of the outlet (So) of the emulsification chamber being between 3 mm and 10 mm, said device comprising a straight section (80) of pipe of which the proximal end is connected to the outlet (So) of the emulsification unit (1) and of which the distal end opens into a bend (81) of a pipe with a larger diameter intended to channel the dilution liquid and in such a way as to allow for the conveying of the undiluted emulsion according to a straight trajectory, from the outlet (So) of the emulsification unit (1), to the location of the dilution, without a change in direction.
9. Installation for manufacturing according to claim 8 wherein the emulsification unit (1) has a single couple rotor (3)/stator (4) and wherein the rotor (3) and the stator (4) each have concentric gear rims, with the rims of the stator and of the rotor being mutually interlocked.
10. Installation according to claim 9, wherein the stator (4) is positioned between the rotor (3) and said fluid inlets (E1, E2) in said emulsification chamber, with the stator (4) comprising a central opening (40), with a diameter less than the average diameter of the gear rims, with the central opening (40) intended to be passed through by the jets of the fluid inlets (E1, E2), as well as a wall (41) extending from the central opening (40) and to the gear rims of the stator, by flaring.
11. Installation according to one of claims 8 to 10, wherein the axes of the fluid inlets (E1, E2) are inclined with respect to the axis (A) of the rotor in such a way that their jets cross, in the emulsification chamber (2).
12. Installation according to one of claims 8 to 11, wherein the emulsification unit comprises a set of removable nozzles (7) intended to allow for the changing of the diameter of the outlet So.
13. Installation for manufacturing the emulsion according to one of claims 8 to 12 comprising two emulsification units (1, 1"), in parallel, as well as a set of solenoid valves (9, 10, 11) that make it possible to carry out the emulsion, from the same source of ASA and from the same solution of cationic starchy material, at one of the two emulsification units (1, 1"), while the other emulsification unit implements a cleaning cycle.
14. Ensemble comprising a paper machine and an installation for continuously manufacturing an emulsion of ASA in an aqueous solution of cationic starchy material in accordance with one of claims 8 to 13 and connected to the paper machine.
15. Method of gluing a sheet of paper of carton wherein:

    a) an alkenyl succinic anhydride emulsion is obtained, referred to as ASA, in an aqueous solution of cationic starchy material by the implementing of the method according to one of claims 1 to 7,

    b) a composition of gluing containing an emulsion manufactured in the step a) is used in an operation of gluing a sheet of paper or carton.

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