FR2815343A1 - New stabilized concentrated gluconic acid compositions, useful in the preparation or as additives to mineral hydraulic binders such as cements - Google Patents

Abstract

Aqueous stable gluconic acid compositions in the form of a salt, free acid and/or lactone. An aqueous stable gluconic acid composition has the following characteristics - a pH greater than 4 ; - a dry matter content of at least 50% ; - a gluconate ion content of at least 50%(as total dry wt.) relative to the dry material wt. of the composition ; - a sodium ion content less than 8%(as dry wt. relative to total dry wt. of composition) ; and - a sufficient amount of a stabilizing agent based on saccharides other than gluconic acid, amines or amine derivatives or mixtures of these. An Independent claim is included for the use of the compositions.

Description

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NEW COMPOSITION OF GLUCONIC ACID, CONCENTRATED, STABLE AND POOR IN SODIUM
The present invention relates to a new composition of gluconic acid, concentrated, stable and low in sodium, said gluconic acid being in the form of at least one of its salts, and optionally free acid and / or d 'one of its lactones. It also relates to the use of a stabilizing agent selected for the preparation of said composition. Finally, it relates to the use of said composition in various application fields and, in particular, for the preparation of compositions of mineral binders or of adjuvants for mineral binders.

 The term “mineral binder” means any hydraulic binder, in particular any mineral powder, capable of forming with water a paste which sets and hardens progressively, even in the absence of air. This definition applies, inter alia, to cements, to natural or artificial hydraulic lime, to mixtures such as mortars, grout, plasters and concretes, based on ground cement and / or lime, water and / or aggregates. (sands, gravel, pebbles, ...), with the raw materials used in the manufacture of cements such as pozzolans, clinkers, slag, limestone fillers and silica fumes. By mineral binder is also meant any plaster composition and, more broadly, any non-hydraulic binder based on calcium sulphate, gypsum and / or lime.

 Depending on their end use and conditions of use, it is sometimes necessary to add adjuvants to mineral binders such as grinding agents or grinding aids, plasticizers, water-plasticizers and superplasticizers. These adjuvants make it possible, for example, to modify the workability, setting, hardening, resistance, durability and / or certain other properties of the mineral binder.

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Many plasticizing-water reducing or superplasticizing products are already used such as molasses, lignosulfonates, sulfonated naphthalene formaldehyde condensates or sulfonated melamine formaldehyde condensates, polyacrylates.

 Among these, oxidized sugars, in particular gluconic acid as well as its salts and / or its lactones, occupy a place of choice because very good plasticizers and water reducers, but also retarders of setting, moreover allowing '' improve the resistance of concrete at 28 days.

 They are also described as grinding agents in international patent application WO 98/37970. The notion of grinding improvement agent appears in its broadest sense, relating to clinkers, ores, ceramics, pigments or coal.

 The use of gluconic acid, its salts and / or its lactones, in the field of mineral binders must be understood here according to all its variants, including very specific applications such as the cementing of wells in the industry of oil and gas.

 The use of these products in plasters is also known from French patent FR 2 707 626, in particular. Associated with an anionic melamine formaldehyde resin, they reduce the amount of mixing water to be added to powdered plaster. Reinforcing the water-reducing power of the resin, they provide a setting retarding function and thus allow workability, or time of use of the paste, which is suitable despite the reduction in the amount of water.

 It is emphasized, in this patent, that interest exists as much for prefabricated plaster panels as for plaster tiles, plaster-based coatings, finishing and molding products which involve significant quantities of plaster .

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The behavior of gluconic acid and gluconates vis-à-vis plaster, and more generally, calcium sulfate, finds particular applications as described in US Pat. No. 3,688,829.

- la solubilité des complexes formés, l'expression de ces propriétés complexantes dans de larges gammes de pH, - une capacité d'élimination de salissures, - des propriétés anti-redéposition, - un respect des couleurs, - une acidité faible, - la préservation de l'environnement,... It is also known that the gluconate ion has a certain number of advantages during its use: - complexing properties, in particular with respect to metals,

- the solubility of the complexes formed, the expression of these complexing properties in wide pH ranges, - a capacity for removing dirt, - anti-redeposition properties, - respect for colors, - low acidity, - the preservation of the environment,...

 These many aspects have led to very diverse applications, which are furthermore authorized by its moderate cost.

 An article by PFIZER in American Dyestuff Reporter from October 1948 underlines the interest of its use in the textile industry, for scouring, bleaching or dyeing materials as widespread as wool, silk, cotton, cellulose regenerated, as well as for printing cellulosic materials.

 On a similar path, but later, the article Mechanism of Magnesium Retardation of Cellulose Dégradation During Oxygen Bleaching (TAPPI - June 1973), uses the same properties in the context of bleaching paper pulp.

 The properties of the gluconate ion thus highlighted (and the essential of which appears in an article by DT Sawyer-April 1964-Chemical Review, 633- 643), have led to a progressive but significant widening of its fields of application .

 This is the case for cleaning textile materials, as described in patent EP 0 425 369 in the name of

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demanderesse, ou de la vaisselle, comme décrit dans le brevet allemand 1 915 056, notamment dans le cadre du remplacement (partiel) des phosphates dans les compositions de lavage utilisées.

Applicant, or dishes, as described in German patent 1,915,056, in particular in the context of the (partial) replacement of the phosphates in the washing compositions used.

 Gluconic acid and gluconates are commonly used as sequestering agents in washing bottles and glassware in general.

Their use has a number of advantages such as the removal of haze and rust spots on the glass, the elimination of scale and rust deposits on the washing equipment.

 This field of use, particularly interesting for washing bottles of milk or beer, can find an extension in modern technologies, for example the cleaning of membranes after ultrafiltration of milk (Journal of Dairy Research- (1992) 59, pp 29-38).

 The intervention of the gluconate ion has also been claimed for the cleaning of metal surfaces, in particular chemical or electrolytic degreasing, stripping eliminating rust and old paints, or also for the deposition, or plating, of metals on other .

 It is, more generally, useful for the preparation of metal surfaces further comprising, in particular, chemical or electrolytic activation phases, or electrolytic deposits, such as the zinc plating described in French patent FR 2 350 409, in the name of the plaintiff.

 It can also be of interest to polishing or polishing, chemical or electrolytic.

 The use of the gluconate ion also concerns the surface conversion of aluminum or satin-finishing, or more generally, the chemical conversion of metallic surfaces such as steel, described in patent EP 0 102 284 in the name of the applicant.

 The intervention of the gluconate ion also relates to the inhibition of corrosion by water and, in particular, by the oxygen dissolved therein,

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substrats métalliques tels que ceux à base de fer, de cuivre, de nickel, d'aluminium et autres, des installations industrielles, en particulier, de refroidissement, que ce soit en circuits ouverts ou fermés, comme décrit dans le brevet français FR 2 512 072 au nom de la demanderesse.

metallic substrates such as those based on iron, copper, nickel, aluminum and others, industrial installations, in particular, cooling, whether in open or closed circuits, as described in French patent FR 2,512 072 in the name of the plaintiff.

 This property relating to the annihilation of the corrosive nature of dissolved oxygen can also be exploited in very specific fields such as the enhanced recovery of petroleum as described in patent EP 0 272 887.

 The intervention of the gluconate ion is still recommended in the context of applications as diverse as the elimination of splashes and deposits of cement, the manufacture of calcium chloride or chlorine, photography, the paint industry, the polycarbonate industry, the stabilization of sodium aluminate solutions or even stable xanthan gum solutions.

masse partielle, un réchauffage à 50-60oC permet alors de solubiliser les cristaux présents et d'obtenir une solution transparente sans modification des caractéristiques du produit. However, it was quickly noticed that, due to the ease of formation of lactone (s), it was difficult to prepare anhydrous gluconic acid compositions. This has resulted in a practice of marketing aqueous solutions of this acid having a dry matter (DM) of about 50%. Such solutions have insufficient stability and require in particular to be stored above 15-20oC to avoid any risk of crystallization. In the event of a catch in

partial mass, reheating to 50-60oC then makes it possible to dissolve the crystals present and to obtain a transparent solution without modifying the characteristics of the product.

 Beyond this drawback, those skilled in the art have realized that, given the extremely low pH of said solutions (generally of the order of 2.0), neutralization with sodium hydroxide is, in many cases case, necessary for their implementation in various applications (admixtures for concrete or plaster,

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compositions détergentes entre autres). Cependant, pour les liants minéraux par exemple, on constate des problèmes de prise dus à la présence excessive de sodium, ainsi que des phénomènes indésirables tels que le gonflement et/ou le vieillissement accéléré des bétons, ou l'apparition d'efflorescences sur les ouvrages.

detergent compositions among others). However, for mineral binders for example, there are setting problems due to the excessive presence of sodium, as well as undesirable phenomena such as swelling and / or accelerated aging of concrete, or the appearance of efflorescence on the works.

 Partially neutralized qualities of sodium gluconate then appeared, having a DM of the order of 60% and improved stability.

 Such products have advantages such as being more concentrated, being less prone to crystallization. However, their pH remains low (always below 3.9) and their high sodium level (-10.5 - 11%), after neutralization at pH 7.0, remains unacceptable vis-à-vis current criteria, in particular those used for the admixture of concrete, for example.

 In addition, gluconic acid solutions with 50% DM or partially neutralized and marketed at around 60% DM remain at a relatively high cost price.

 In parallel, and in particular on the basis of this last criterion, so-called technical solutions of sodium gluconate have been developed, obtained by fermentation or by chemical oxidation of sugar (s).

 Although very popular, they have the disadvantage of necessarily low DM (generally of the order of 45%) to avoid any risk of crystallization, as well as high sodium levels, hardly compatible with current requirements.

 It follows from the above that, to the knowledge of the Applicant, there is no aqueous gluconic acid composition available which simultaneously has the following advantages: - good physical stability,

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- un pH suffisamment élevé pour ne nécessiter, pour la neutralisation, que des quantités réduites d'alcali et ne pas être corrosive, une teneur en ions sodium néanmoins suffisamment faible pour éviter la manifestation des effets négatifs de cet ion, une matière sèche suffisamment élevée et avantageuse pour en réduire sensiblement les coûts de transport et de stockage, ou encore les risques microbiologiques liés à ces opérations, - une teneur en ions gluconate suffisante pour garantir la pleine manifestation des propriétés offertes par cette entité.

- a sufficiently high pH to require, for neutralization, only reduced quantities of alkali and not to be corrosive, a content of sodium ions nevertheless sufficiently low to avoid the manifestation of the negative effects of this ion, a sufficiently high dry matter and advantageous for significantly reducing the costs of transport and storage, or even the microbiological risks associated with these operations, - a content of gluconate ions sufficient to guarantee the full manifestation of the properties offered by this entity.

 And the merit of the Applicant Company is to have found, after numerous researches, that it was now possible to propose such compositions, for example compositions whose gluconic acid is mainly in the form of salt (s), since said compositions contained a sufficient amount of stabilizing agent (s) of selected nature.

 More specifically, the subject of the present invention is a stable aqueous composition of gluconic acid, said acid being in the form of at least one salt and optionally in the form of free acid and / or one of its lactones, said composition being characterized in that it has: - a pH greater than 4.0, - a dry matter at least equal to 50%, - a content of gluconate ions at least equal to 50%, expressed in total dry weight d gluconate ions, coming from gluconic acid in the form of salt (s) and optionally free acid and / or lactone (s), relative to the dry matter of said composition, - a sodium ion content of less than 8%, expressed as total dry weight relative to the dry matter of said composition, and an effective content of a stabilizing agent chosen from the group comprising:

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saccharides autres que l'acide gluconique, ses sels et lactones, les composés aminés et les mélanges quelconques d'au moins deux quelconques de ces produits.

saccharides other than gluconic acid, its salts and lactones, amino compounds and any mixtures of at least any two of these products.

- ni variation notable de viscosité apparente. Par quantité efficace au sens de la présente invention, on entend une quantité d'agent (s) de stabilisation au moins égale à celle suffisante pour que la composition d'acide gluconique soit stable conformément à la définition donnée ci-avant. En fonction de la nature de l'agent de stabilisation, cette quantité suffisante peut être plus ou moins basse, y compris inférieure à 3 %, exprimée par rapport à la matière sèche de ladite composition. Dans le cadre de l'invention cependant, on privilégie des quantités efficaces se situant généralement entre 3 et 50 %. The term “stable composition” within the meaning of the present invention means any composition of the kind in question which, if it is subjected to storage for 1 month at 20 ° C., does not generally change appearance and in particular does not show such storage: - no formation of crystals, visible to the naked eye,

- no significant variation in apparent viscosity. The term effective amount within the meaning of the present invention means an amount of stabilizing agent (s) at least equal to that sufficient for the gluconic acid composition to be stable in accordance with the definition given above. Depending on the nature of the stabilizing agent, this sufficient amount may be more or less low, including less than 3%, expressed relative to the dry matter of said composition. In the context of the invention, however, effective quantities are generally situated between 3 and 50%.

 As a result of which, according to a preferred variant, the gluconic acid composition according to the invention as described above is characterized in that it has a total content of saccharides other than gluconic acid, its salts and lactones , and in amino compounds at least equal to 3% and at most equal to 50%, expressed in total dry weight relative to the dry matter of said composition.

 The Applicant Company has found that the presence, in the proportions indicated above, of particular products constituted by saccharides other than gluconic acid (in whatever form), amino compounds and mixtures of these products, gave the gluconic acid compositions containing them, not only good stability, and in particular a non-crystallizable character, at room temperature (200C) but also:

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- une bonne stabilité, et notamment un caractère non cristallisable, à basse température (5OC), la capacité de pouvoir, si besoin, être avantageusement concentrées puis stockées, transportées et/ou utilisées à des matières sèches (MS) relativement élevées, par exemple comprises entre 52 et 75 %, - la capacité de ne contenir parallèlement, si besoin, que des taux limités en métaux alcalins ou alcalino-terreux, et notamment des taux en ion sodium inférieurs à 8 % (sec/sec) et ce, sans nuire à l'efficacité applicative desdites compositions, - une efficacité améliorée dans divers domaines industriels tels que notamment la préparation de compositions de liant minéral ou d'adjuvants destinés auxdites compositions.

- good stability, and in particular a non-crystallizable nature, at low temperature (5OC), the ability to be able, if necessary, to be advantageously concentrated then stored, transported and / or used with relatively high dry matter (MS), for example between 52 and 75%, - the capacity to contain in parallel, if necessary, only limited levels of alkali or alkaline-earth metals, and in particular sodium ion levels of less than 8% (dry / dry), without adversely affect the application efficiency of said compositions, - improved efficiency in various industrial fields such as in particular the preparation of mineral binder compositions or of adjuvants intended for said compositions.

 According to a variant, the gluconic acid composition according to the invention is characterized in that it has a total content of saccharides other than gluconic acid, its salts and lactones, of between 3 and 47%, preferably between between 10 and 45%, said content being expressed in total dry weight of said saccharides relative to the dry matter of said composition.

 This total content may advantageously be between 15 and 40%, in particular between 25 and 40%, it being understood that this total content may result from the presence only of a single saccharide other than gluconic acid, its salts and lactones or conversely result from the combined presence of several saccharides other than gluconic acid, its salts and lactones.

 By saccharides other than gluconic acid, its salts and lactones within the meaning of the present invention, is understood in particular to mean all: monosaccharides, disaccharides, trisaccharides, oligosaccharides and polysaccharides, of linear, cyclic or branched structure, which have not undergone no particular oxidation or reduction reaction such as, for example, glucose,

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fructose, le mannose, le xylose, le ribose, l'arabinose, le maltose, le maltotriose, le galactose, le lactose, le saccharose, les sirops de glucose, les maltodextrines, les pyrodextrines, les cyclodextrines, les amidons, les amidons modifiés physiquement, l'inuline et les mélanges quelconques d'au moins deux quelconques de ces produits, - des saccharides de structure linéaire, cyclique ou branchée tels que ceux précités et leurs mélanges, ayant subi une réaction de réduction, en particulier une réaction d'hydrogénation catalytique, quelle qu'elle soit et à quelque moment que ce soit, comme par exemple le sorbitol, le mannitol, le xylitol, le ribitol, l'arabitol, le maltitol, le maltotriitol, le galactitol, le lactitol, le glucosido-1-6 mannitol, l'isomaltitol, le palatinitol, l'érythritol, les sirops de glucose hydrogénés, les maltodextrines et pyrodextrines hydrogénées et les mélanges quelconques d'au moins deux quelconques de ces produits.

fructose, mannose, xylose, ribose, arabinose, maltose, maltotriose, galactose, lactose, sucrose, glucose syrups, maltodextrins, pyrodextrins, cyclodextrins, starches, modified starches physically, inulin and any mixtures of at least any two of these products, - saccharides of linear, cyclic or branched structure such as those mentioned above and their mixtures, having undergone a reduction reaction, in particular a reaction of catalytic hydrogenation, whatever it is and at any time, such as for example sorbitol, mannitol, xylitol, ribitol, arabitol, maltitol, maltotriitol, galactitol, lactitol, glucosido- 1-6 mannitol, isomaltitol, palatinitol, erythritol, hydrogenated glucose syrups, maltodextrins and hydrogenated pyrodextrins and any mixtures of at least any two of these products.

 - Saccharides resulting from internal dehydration, in one or more stages, reduced products such as those mentioned above and in particular from internal dehydration of sorbitol or mannitol such as for example sorbitan, isosorbide, mannitan and isomannide.

 saccharides of linear, cyclic or branched structure such as those mentioned above and their mixtures, having undergone an oxidation reaction, including catalytic oxidation, whatever it is and at any time whatsoever, partial or total and in the form of free acid and / or salt (s) and / or lactone (s) with the exception of gluconic acid, its salts and lactones, such oxidized saccharides may consist, for example, into glucaric acid, glucuronic acid, glucoheptonic acid, arabinonic acid, arabinaric acid, xylonic acid, xylaric acid, lactobionic acid, maltobionic acid, maltotriionic acid, acid

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érythorbique, des sirops de glucose oxydés, des maltodextrines et pyrodextrines oxydées et les mélanges quelconques d'au moins deux quelconques de ces produits.

erythorbic, oxidized glucose syrups, oxidized maltodextrins and pyrodextrins and any mixtures of at least any two of these products.

l'un quelconque des saccharides, hydrogénés ou non, oxydés ou non, décrits précédemment, notamment les dérivés de faible poids moléculaire présentant au moins deux fonctions hydroxyle ou carboxyle tels que par exemple le glycérol et les (sels des) acides oxalique, tartrique, lactique, citrique, malique, fumarique ou succinique. derivatives derived from the chemical transformation of any of the saccharides, hydrogenated or not, oxidized or not, described above such as, for example, those obtained by etherification, esterification, crosslinking, boration, sulfation or sulfonation of one any of said saccharides. derivatives derived from biological transformation, in particular by fermentation, from

any of the saccharides, hydrogenated or not, oxidized or not, described above, in particular the low molecular weight derivatives having at least two hydroxyl or carboxyl functions such as for example glycerol and the (salts of) oxalic, tartaric acids, lactic, citric, malic, fumaric or succinic.

 As indicated, the stabilizing agent contained in the compositions according to the invention can also consist, in whole or in part, of at least one amino compound.

 According to a variant, the gluconic acid composition according to the invention is characterized in that it has a total content of amines of between 6 and 50%, preferably between 8 and 40%, said content being expressed by weight total dryness of said amines relative to the dry matter of said composition.

By amino compound within the meaning of the present invention is meant in particular simple amines, whether primary, secondary or tertiary, such as, for example, monoethanolamine, diethanolamine or triethanolamine but also more complex amino derivatives such as 2 -amino- 2methyl 1 propanol (hereinafter AMP), tetraethylene pentamine or those corresponding to the general formula:

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dans laquelle : - Ri, R2 et R3, qui peuvent être identiques ou différents, représentent l'atome d'hydrogène ou un groupe alkyle, alkyle substitué, alcène, aryle ou aralkyle, B représente une chaîne hydrocarbonée comportant au moins un motif-CH2-et dont le nombre de carbones situés sur la chaîne est inférieur ou égal à 10, - A représente les groupements :

dans lesquels : - X représente un halogène, - R5, R6 et R7, qui peuvent être identiques ou différents, représentent des radicaux alkyle, alkyle substitué, alcène, aryle ou aralkyle.

in which: - Ri, R2 and R3, which may be identical or different, represent the hydrogen atom or an alkyl, substituted alkyl, alkene, aryl or aralkyl group, B represents a hydrocarbon chain comprising at least one CH2 unit -and whose number of carbons located on the chain is less than or equal to 10, - A represents the groups:

in which: - X represents a halogen, - R5, R6 and R7, which can be identical or different, represent alkyl, substituted alkyl, alkene, aryl or aralkyl radicals.

 The term “amino compound” also means, in particular: - natural proteins of animal or vegetable origin as well as all the products capable of being obtained, in any manner, from these proteins such as poly-, oligo - and dipeptides and amino acids, - synthetic polymers of amino acids, for example aspartic acid, and their derivatives, - amino derivatives of acids or acid polymers such as for example amino derivatives of di acids -, tri-, tetra- or pentaacetic, mono-or disuccinic, tartaric, citric or phosphonic such as the derivatives known to those skilled in the art under the abbreviations of NTA, EDTA, DTPA, EDTMP, MGDA, EDMS and EDDS .

 The inventive concept of the present invention is therefore also based on the use of at least one saccharide other than gluconic acid, its salts and lactones and / or at least one amino compound to improve the stability of a composition d gluconic acid having a DM at least equal to 50%, said gluconic acid being in the form of salt (s) and

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éventuellement sous forme d'acide libre et/ou de lactone (s).

optionally in the form of free acid and / or lactone (s).

 As indicated, the presence of such a stabilizing agent in the gluconic acid composition according to the invention has, inter alia, the advantage of being associated, if desired, with a limited presence of sodium ions within the same composition.

 According to a preferred variant of the present invention, said composition is characterized in that it has a content of sodium ions at most equal to 7%, preferably at most equal to 6%, expressed in total dry weight relative to the material said composition.

 This sodium ion content can in particular be between 2 and 5% approximately.

 According to another very advantageous variant, the composition according to the invention has a weight ratio between respectively its total content of sodium ions and its total content of stabilizing agent (s), less than 40%, preferably less than 35%, expressed in dry / dry. This ratio can, for example, be between 0 and 25% approximately.

 The presence of a stabilizing agent also makes it possible, as already pointed out, to advantageously propose gluconic acid compositions which are stable while exhibiting a high MS, said MS being moreover relatively rich in gluconate ions, as well as a pH relatively high and close to the pH at which said compositions are ultimately applied.

 In particular, the composition according to the invention can be characterized in that it has: - a dry matter at least equal to 52%, preferably between 52 and 65%, and - a pH at least equal to 4.5 , preferably at least 5.0.

 According to another variant, the gluconic acid composition according to the invention is characterized in that it has a content of gluconate ions at least

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égale à 55 %, de préférence au moins égale à 60 %, et au plus égale à 75 %, exprimée en poids sec total d'ions gluconate provenant de l'acide gluconique sous forme de sel (s) et, éventuellement, d'acide libre et/ou de lactone (s).

equal to 55%, preferably at least equal to 60%, and at most equal to 75%, expressed in total dry weight of gluconate ions originating from gluconic acid in the form of salt (s) and, optionally, of free acid and / or lactone (s).

non cristallisables à 20oC, a fortiori également non cristallisables à 5 C et ce, tout en présentant des caractéristiques élevées de pH, de MS et de teneur en ions gluconate. As mentioned above, the compositions of gluconic acid, its salts and / or lactones have been used industrially and commercially for several decades. However, to the knowledge of the Applicant, it had hitherto never been designed, a fortiori prepared and implemented, such compositions in liquid form which are

non-crystallizable at 20oC, a fortiori also non-crystallizable at 5 C and this, while exhibiting high characteristics of pH, MS and content of gluconate ions.

 This observation is particularly valid for sodium gluconate compositions, in particular those with low contents of sodium ions.

stockage de 1 mois à la température en question (200C ou SOC), mais encore que la même composition, si elle est ensemencée avec 1 % en poids (sec/sec) de cristaux de gluconate de sodium et mélangée (5 minutes à 100 tours/minute), ne montre pas d'augmentation significative du poids sec de cristaux après un stockage de 1 mois à la température en question (200C ou 5 C). By non-crystallizable, it is meant that the composition not only does not generate crystals visible to the naked eye, gluconic acid (in free form, salt (s) and / or lactone (s)) after a

storage for 1 month at the temperature in question (200C or SOC), but still the same composition, if it is seeded with 1% by weight (dry / dry) of sodium gluconate crystals and mixed (5 minutes at 100 revolutions / minute), does not show a significant increase in the dry weight of crystals after storage for 1 month at the temperature in question (200C or 5 C).

 As a result of which, the present invention relates to an aqueous composition of the genus in question characterized a) in that it has: - a pH greater than 4.0, - a dry matter at least equal to 50%, - a content of gluconate ions at least 50%, expressed in total dry weight of gluconate ions

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provenant de l'acide gluconique sous forme de sel (s) et éventuellement d'acide libre et/ou de lactones, et b) en ce qu'elle est non cristallisable à 20oC, de préférence non cristallisable à 20 C et à 5 C.

from gluconic acid in the form of salt (s) and optionally free acid and / or lactones, and b) in that it is non-crystallizable at 20 ° C., preferably non-crystallizable at 20 ° C. and 5 ° C. .

 According to a very advantageous variant, said composition is characterized in that it has: - a pH at least equal to 4.5, preferably at least equal to 5.0, - a dry matter at least equal to 52%, preferably between 52 and 65%, - a content of gluconate ions at least equal to 55%, said ions mainly coming (i. e for 50% at least by weight) of gluconic acid salt (s), and - a sodium content at most equal to 8%, preferably at most equal to 7%, expressed in total dry weight relative to the dry matter of said composition.

 As a result, new compositions of gluconic acid are now available in the form, exclusive or not, of salt (s), in particular new compositions of sodium gluconate, the conditions of transport and storage of which are improved, in particular with a view to reducing the cost thereof and achieving the best possible compromise between resistance to crystallization and resistance to microbial attack.

 These compositions, concentrated and stable, also have the advantage of being able to exhibit particularly low concentrations of sodium ions and thereby significantly increased possibilities of application in industrial fields such as, for example, the preparation of mineral binders, in particular of cement, mortar, concrete, grout, plaster or plaster compositions or of adjuvant compositions intended for said mineral binder compositions.

 Finally, these compositions have the advantage of being generally at least as effective, or even

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plus efficaces, que les compositions de l'art antérieur. C'est notamment le cas dans le domaine précité des liants minéraux comme il sera exemplifié par ailleurs. Dans ce domaine, les compositions selon l'invention permettent en particulier : - d'améliorer la plasticité et/ou les propriétés mécaniques de liants minéraux à base de ciment ou de chaux hydraulique, - d'améliorer la stabilité chimique d'adjuvants, par exemple de retardateurs de prise, stockés et utilisés dans les pays chauds, - d'améliorer l'ouvrabilité de compositions de plâtres, notamment dans le cadre de formulations destinées à réduire la quantité d'eau à mettre en oeuvre, de mieux maîtriser globalement la quantité d'eau ajoutée lors de la préparation et/ou de l'usage d'un adjuvant pour liant minéral.

more effective than the compositions of the prior art. This is particularly the case in the aforementioned field of mineral binders as will be exemplified elsewhere. In this field, the compositions according to the invention make it possible in particular: - to improve the plasticity and / or the mechanical properties of mineral binders based on cement or hydraulic lime, - to improve the chemical stability of adjuvants, by example of setting retarders, stored and used in hot countries, - to improve the workability of plaster compositions, in particular in the context of formulations intended to reduce the amount of water to be used, to better control the amount of water added during the preparation and / or use of a mineral binder additive.

 Furthermore, because of the numerous advantages which they demonstrate and which have been mentioned above, the compositions according to the invention can be advantageously used in all types of industries and in particular for the preparation of compositions intended for the industries of detergency, metallurgy, chemistry, oil and gas extraction, water treatment, stationery, corrugated or flat cardboard, plastics, textiles, leather, paints, photography, fertilizers and phytosanitary products.

 Gluconic acid salt compositions containing sorbitol as a stabilizing agent can, for example, be used favorably in the fields of detergency or satin-finishing of aluminum.

 The present invention will be described in more detail with the aid of the examples which follow and which are in no way limiting.

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EXAMPLE 1 In the context of this example, the storage behavior at 20 ° C. and Soc respectively, in particular in terms of resistance to crystallization, of two gluconic acid compositions according to the invention (hereinafter called COMPOSITIONS respectively) is compared. A and B) to that of two gluconic acid compositions, representative of products on the market and not in accordance with the present invention (hereinafter designated COMPOSITIONS T1 and T2 respectively).

ses sels et lactones ( SACCHARIDES en % en sec/sec) ainsi que de teneur totale en ions sodium dz SODIUM en % en sec/sec).

The compositions tested have the following characteristics in terms of dry matter (MS in%), pH value (pH), total content of gluconate ions (GLUCONATE in% dry / dry), total content of saccharides other than gluconic acid ,

its salts and lactones (SACCHARIDES in% dry / dry) as well as the total content of sodium ions in SODIUM in% dry / dry).

Pour chacune de ces COMPOSITIONS A, B, Tl et T2, les ions gluconate sont majoritairement présents sous forme de gluconate de sodium, l'autre source significative desdits ions étant constituée d'acide gluconique libre. MS pH GLUCONATE SACCHARIDES SODIUM COMPOSITION A 58 6, 0 61, 6 31, 5 5, 8 COMPOSITION B 55 6, 0 62, 5 29, 8 6, 5 COMPOSITION T1 45 5, 5 72, 0 11, 3 10, 1 COMPOSITION T2 41 5, 9 69, 6 20, 2 8, 8

For each of these COMPOSITIONS A, B, T1 and T2, the gluconate ions are mainly present in the form of sodium gluconate, the other significant source of said ions being constituted by free gluconic acid.

 According to the tests defined previously in the general description, it is checked whether each of these COMPOSITIONS is stable, in particular non-crystallizable, after 1 month of storage at 20 ° C. or at 5 ° C.

 For each COMPOSITION which thus proves to be stable, it is checked whether, in addition, it is also non-crystallizable (1 month at 200C or SOC) despite a

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ensemencement de 1 %, en poids (sec/sec), de cristaux de gluconate de sodium, cristaux potentiellement aptes à jouer le rôle d'amorces de cristallisation.

seeding of 1%, by weight (dry / dry), of sodium gluconate crystals, crystals potentially capable of playing the role of primers of crystallization.

 More generally, for each COMPOSITION, the maximum dry matter is determined (MSM in%) for which the composition in question, as the case may be concentrated or diluted in demineralized water but with respective richnesses of gluconate ions, sodium ions and saccharides (dry / dry) unmodified, is non-crystallizable, and this: - at 20oC or at SoC, without or with seeding of crystals (variants hereinafter designated respectively WITHOUT and WITH).

de stockage (200C ou SOC) et de la présence éventuelle d'amorces de cristallisation ( SANS ou AVEC ), on obtient les valeurs de MSM (%) ci-après :

200C 20 C 5 C 5 C SANS AVEC SANS AVEC COMPOSITION A 65 % 64 % 60 % 58 % COMPOSITION B 65 % * 65 % 60 % 55 % COMPOSITION T1 46 % 44 % 44 % 42 % COMPOSITION T2 55 % 52 % 50 % 48 %

* à 70 % formation de rares cristaux visibles. Depending on the COMPOSITION, the temperature

storage (200C or SOC) and the possible presence of crystallization primers (WITHOUT or WITH), the MSM values (%) are obtained below:

200C 20 C 5 C 5 C WITHOUT WITHOUT WITH COMPOSITION A 65% 64% 60% 58% COMPOSITION B 65% * 65% 60% 55% COMPOSITION T1 46% 44% 44% 42% COMPOSITION T2 55% 52% 50% 48%

* at 70% formation of rare visible crystals.

(SOC) et en particulier être non cristallisables à ces températures, y compris donc à 5 C et ce, malgré la mise en oeuvre de cristaux exogènes aptes à favoriser un phénomène de cristallisation du gluconate de sodium. These results show overall that compositions having MS significantly greater than 50% such as COMPOSITIONS A and B according to the invention can be stable not only at room temperature but also at low temperature

(SOC) and in particular be non-crystallizable at these temperatures, including therefore at 5 ° C., despite the use of exogenous crystals capable of promoting a phenomenon of crystallization of sodium gluconate.

 It is remarkable to note that in the absence of such exogenous crystals, these COMPOSITIONS A and B can be

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concentrées, si on le souhaite, au moins jusqu'à 60 % de MS et ce, sans qu'apparaisse, même à 5 C, de phénomène de cristallisation.

concentrated, if desired, at least up to 60% DM and this, without the appearance, even at 5 C, of crystallization phenomenon.

 Conversely, the COMPOSITIONS T1 and T2, not in accordance with the invention, cannot validly be concentrated in such MS. COMPOSITION Tl, even if not concentrated, turns out to be intrinsically unstable since it is prone to easily crystallize, despite its relatively low DM (45%).

 COMPOSITION T2, overall more stable than COMPOSITION Tl, could not, for its part, be concentrated at a DM greater than 50% without exhibiting, at SoC, a phenomenon of crystallization, including in the absence of exogenous crystals.

 In addition, COMPOSITIONS A and B according to the invention have the advantage of a lower content of sodium ions than COMPOSITIONS T1 and T2 and therefore of increased applicability, for example in the field of mineral binders. These COMPOSITIONS A and B also have a weight ratio (dry / dry) SODIUM / SACCHARIDES which is respectively 18.4% and 21.8%, much lower than that of COMPOSITIONS T1 (89.4%) and T2 (43 , 6%).

(ci-après désigné MORTIER T0 ) selon la norme CEN 196-1, en mélangeant 450 g de ciment CPA 52, 5 HP avec 1350 g de sable normalisé et 225 g d'eau. EXAMPLE 2
We proceed to the preparation of a witness mortar

(hereinafter designated MORTAR T0) according to standard CEN 196-1, by mixing 450 g of CPA 52, 5 HP cement with 1350 g of standardized sand and 225 g of water.

Likewise, various mortars are prepared as above except that one adds in addition, respectively: - MORTAR A: 0.08% of COMPOSITION A according to the invention described in EXAMPLE 1, quantity expressed relative to the weight of cement (dry / dry), - MORTAR Tl: 0.08% (dry / dry) of COMPOSITION
Tl not in accordance with the invention, described in EXAMPLE 1,

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- MORTIER T2 : 0, 08 % (sec/sec) de COMPOSITION T2 non conforme à l'invention, décrite au niveau de l'EXEMPLE 1.

- MORTAR T2: 0.08% (dry / dry) of COMPOSITION T2 not in accordance with the invention, described in EXAMPLE 1.

For each of the MORTARS TO, Tl, T2 and A, the spread E is measured in mm, the start of setting DP and the end of setting FP in hours and minutes as well as the mechanical resistances at 5 pm (R17H in megapascals or Mpa ) and 28 days (<x R28J in Mpa).

MORTIER TO Tl T2 A E (mm) 235, 5 264, 2 264, 8 260 DP (H + MIN) 4H15 9H50 11H 11H FP (H + MIN) 5H20 12H45 13H 13H R17H (Mpa) 9, 7 1, 7 1, 2 1, 5 R28J (Mpa) 50, 6 56 60 61, 1

Ces résultats montrent que la mise en oeuvre d'une composition d'acide gluconique conforme à l'invention telle que la COMPOSITION A permet de conférer au mortier (MORTIER A) non seulement de bonnes caractéristiques de plasticité (valeur d'étalement augmentée de 24,5 mm par rapport au MORTIER TO) et de retard de prise (début de prise reporté de 6H45 supplémentaires par rapport au MORTIER TO), mais encore une résistance à 28 jours particulièrement élevée ( > 60 Mpa) qui ne peut par ailleurs être atteinte avec les COMPOSITIONS Tl et T2 non conformes à l'invention. The following results are obtained:

MORTAR TO Tl T2 AE (mm) 235, 5 264, 2 264, 8 260 DP (H + MIN) 4H15 9H50 11H 11H FP (H + MIN) 5H20 12H45 13H 13H R17H (Mpa) 9, 7 1, 7 1, 2 1, 5 R28J (Mpa) 50, 6 56 60 61, 1

These results show that the use of a gluconic acid composition in accordance with the invention such as COMPOSITION A makes it possible to impart to the mortar (MORTAR A) not only good plasticity characteristics (spreading value increased by 24 , 5 mm compared to MORTAR TO) and setting delay (start of postponement postponed by 6H45 additional compared to MORTAR TO), but still a particularly high resistance to 28 days (> 60 Mpa) which cannot otherwise be achieved with COMPOSITIONS T1 and T2 not in accordance with the invention.

 As already indicated, the latter also have a higher content of sodium ions than that of said COMPOSITION A and therefore, overall, less applicability in the field of mineral binders.

EXAMPLE 3
In the context of this example, we study the interest, in mineral binders, of COMPOSITIONS C, D, E and F according to the invention containing an amino compound as stabilizing agent, said compound

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aminé (ci-après désigné AMINE ) étant apporté sous la forme respectivement de monoéthanolamine (COMPOSITION C), de diéthanolamine (COMPOSITION D), de triéthanolamine (COMPOSITION E) ou d'AMP (COMPOSITION F).

amine (hereinafter designated AMINE) being provided in the form of monoethanolamine (COMPOSITION C), diethanolamine (COMPOSITION D), triethanolamine (COMPOSITION E) or AMP (COMPOSITION F) respectively.

matières sèches maximales ( MSM en %), à 20 oC ou 5 C, avec ou sans ensemencement de 1 %, en poids (sec/sec), de cristaux de gluconate de sodium (variantes AVEC ou SANS ).

The general characteristics of the said COMPOSITIONS are mentioned below, including their

maximum dry matter (MSM in%), at 20 oC or 5 C, with or without sowing of 1%, by weight (dry / dry), of sodium gluconate crystals (variants WITH or WITHOUT).

Les COMPOSITIONS C, D, E et F selon l'invention se révèlent particulièrement stables. Elles peuvent notamment être présentées à une MS au moins égale à 52 %, voire 59 % (COMPOSITION F) sans présenter de risques de cristallisation et ce, même à Soc. COMPOSITION CDEF MS (%) 52 52 52 52 PH 7, 0 6, 0 5, 3 5, 3 GLUCONATE * (%) 85 79, 4 75, 5 82, 1 SODIUM * (%) 4 3, 6 3, 5 3, 6 AMINE ** (%) 11 17 21 14, 3 MSM / 20 C (WITHOUT) 61 56 55 60 MSM / 20 C (WITH) 61 56 55 60 MSM / 5 C (WITHOUT) 56 52 53 59 MSM / 5 C (WITH) 56 52 53 59 * total content of ions in dry / dry ** total content of amino compound in dry / dry

COMPOSITIONS C, D, E and F according to the invention prove to be particularly stable. They can in particular be presented to a DM at least equal to 52%, or even 59% (COMPOSITION F) without presenting any risk of crystallization, even at Soc.

 It is moreover remarkable that, in addition, the maximum dry matter (MSM) of these COMPOSITIONS, which is therefore high, does not decrease when these COMPOSITIONS are seeded with crystals which are to promote any phenomenon of crystallization, both at 20 ° C. than 5OC.

 These COMPOSITIONS have, among other advantages, a low content of sodium ions, significantly less than 6% (dry / dry).

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Each of COMPOSITIONS C, D and E is tested in a control mortar, in accordance with the protocol described in EXAMPLE 2, except that in the present case: another batch of CPA 52.5 cement is used.
HTS, and - each COMPOSITION is introduced into the mortar at a rate of 0.05% instead of 0.08%, expressed in dry weight relative to the dry weight of cement.

The MORTARS C, D and E are respectively obtained, the main characteristics of which, measured as in EXAMPLE 2, are given below, compared with those obtained in the absence of any adjuvant (MORTAR TO).

MORTAR TO CDEE (mm) 222 253 244, 5 244, 5 DP (H + MIN) 4H15 7hui0 7H45 7hui0 DF (H + MIN) 6H30 8H50 9H 8H15 R17H (Mpa) 8, 8 5, 9 6, 0 6, 0 R28J (Mpa) 52, 0 55, 8 54, 6 55, 8
These results confirm overall that the gluconic acid compositions according to the invention, of high MS and stability, make it possible to confer on mineral binders not only good characteristics of plasticity and retardation of setting but also resistance to 28 days very significantly higher than that obtained in the absence of any adjuvant.

In addition, the COMPOSITIONS C to E described above have, among others, the advantages of: giving these binders resistance at a young age, in this case after 5 p.m., much greater than that generally recognized as necessary for rapid stripping. , namely 5
Mpa.

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de présenter des teneurs en ions sodium significativement inférieures à 8 % et même à
6 % (sec/sec).

to present sodium ion contents significantly below 8% and even
6% (dry / dry).

 It has also been verified that COMPOSITION F, which has all of the above advantages, also makes it possible to obtain the same performance, including resistance, as crystallized sodium gluconate, despite a dosage reduced by 20 %.

EXAMPLE 4
In the context of this example, the advantage of the above-described COMPOSITIONS A and E, in accordance with the invention, is studied in the field of plaster adjuvanting and more particularly as setting retarders.

 A control plaster composition (PLASTER TO) is prepared using a semi-hydrated plaster sold by the company LAFARGE and a water / plaster weight ratio of 0.7.

 Likewise, different plaster compositions are prepared as above except that an additional 0.2% (dry / dry) of, respectively, COMPOSITION A PLASTER A), COMPOSITION E (PLASTER E) is added. or the COMPOSITION Tl described above, not in accordance with the invention.

For each of the PLATERS TO, Tl, A and E, the start of the DP setting, the end of the FP setting and the TP setting time (= FP-DP) are measured, these values being expressed in minutes.

The following results are obtained: PLATRE TO Tl AE DP (mm) 4 35 30 46 FP (MIN) 7 67 62 98 TP (MIN) 3 32 32 52
These results show overall that in the field of plaster compositions, the compositions according to the invention are also very good agents

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retardateurs de prise, au moins aussi efficaces que la COMPOSITION témoin Tl.

setting retarders, at least as effective as the control COMPOSITION Tl.

 It is remarkable to emphasize that, in addition, COMPOSITION E according to the invention makes it possible, with regard to said COMPOSITION Tl, to further significantly improve the workability of the mineral binder and in particular to increase: by 11 minutes the value of DP and therefore the duration during which the plaster can be used between its preparation and its placement on its support, and of 20 minutes the value of TP and therefore the duration during which the plaster, put in place, can be the object finishing operations such as smoothing.

Claims (11)

 1-Stable aqueous composition of gluconic acid, said acid being in the form of at least one salt and optionally in the form of free acid and / or of at least one of its lactones, said composition being characterized in that that it has: - a pH greater than 4.0, - a dry matter at least equal to 50%, - a content of gluconate ions at least equal to 50%, expressed in total dry weight of gluconate ions, originating from gluconic acid in the form of salt (s) and optionally free acid and / or lactone (s), relative to the dry matter of said composition, - a sodium ion content of less than 8%, expressed by weight total dry relative to the dry matter of said composition, and an effective content of a stabilizing agent chosen from the group comprising saccharides other than gluconic acid, its salts and lactones, amino compounds and any mixtures of at least any two of these products.  2-Composition according to claim 1 characterized in that it has a total content of saccharides other than gluconic acid, its salts and lactones and amino compounds, at least equal to 3% and at most equal to 50%, expressed in total dry weight relative to the dry matter of said composition.  3-Composition according to claim 2 characterized in that it has a total content of saccharides other than gluconic acid, its salts and lactones, between 3 and 47%, preferably between 10 and 45%, expressed by weight total dry with respect to the dry matter of said composition.  4-Composition according to claim 2 characterized in that it has a total content of amino compounds between 6 and 50%, <Desc / Clms Page number 26>  preferably between 8 and 40%, expressed as total dry weight relative to the dry matter of said composition.

 5-Composition according to any one of claims 1 to 4, characterized in that it has a content of sodium ions at most equal to 7%, preferably at most equal to 6%, expressed in total dry weight relative to the dry matter of said composition.  6-Composition according to any one of claims 1 to 5 characterized in that it has: - a dry matter at least equal to 52%, preferably between 52 and 65%, and - a pH at least equal to 4 , 5, preferably at least 5.0.  7-Composition according to any one of claims 1 to 6 characterized in that it has a content of gluconate ions at least equal to 55%, preferably at least equal to 60%, and at most equal to 75%, expressed by total dry weight of gluconate ions originating from gluconic acid in the form of salt (s) and, optionally, free acid and / or lactone (s).  8-An aqueous composition of gluconic acid, said acid being in the form of at least one salt and optionally in the form of free acid and / or one, at least, of its lactones, said composition being characterized a) in what it has: - a pH greater than 4.0, - a dry matter at least equal to 50%, - a content of gluconate ions at least equal to 50%, expressed in total dry weight of gluconate ions originating from gluconic acid in the form of salt (s) and optionally free acid and / or lactones, and b) in that it is not crystallizable at

 20oC, preferably not crystallizable at 20 C and SOC. 9-Composition according to claim 8 characterized in that it has: <Desc / Clms Page number 27>  reference preferably to at most 7%, expressed in total dry weight p relative to the dry matter of said composition.

 - a pH at least equal to 4.5, preferably at least equal to 5.0, - a dry matter at least equal to 52%, preferably between 52 and 65%, - a content of gluconate ions at least equal at 55%, said ions coming mainly from gluconic acid salt (s), and - a sodium content at most equal to 8%,

 10-Composition according to any one of claims 1 to 9, characterized in that it has a weight ratio (dry / dry) between its total content of sodium ions on the one hand and its total content of agent (s) stabilization on the other hand, less than 40%, preferably less than 35%.  11- Use of a composition according to any one of claims 1 to 10 for the preparation of compositions of mineral binders, in particular of compositions of cements, mortars, concretes, grout, plasters or plasters, for the preparation of adjuvant compositions intended to said compositions of mineral binders or for the preparation of compositions intended for the detergency, metallurgy, chemical, oil and gas extraction, water treatment, stationery, corrugated or flat board industries , plastics, textiles, leather, paints, photography, fertilizers and phytosanitary products.