Stable organic compositions comprising zeolites

Abstract

The present invention relates to a composition comprising zeolite crystals and a hydroxylated oil stabilized by an organophilic phyllosilicate dispersant. The invention also relates to the use of said composition for drying organic compounds, compositions or solutions.

Description

STABLE ORGANIC COMPOSITIONS COMPRISING ZEOLITHS

[0001] The present invention relates to the field of stable organic compositions comprising zeolites, more particularly stable liquid organic compositions comprising zeolites and very particularly stable compositions of hydroxylated organic liquids or even hydroxylated organic oils, comprising zeolites.

[0002] Such compositions are often and most generally used to dry organic liquids and for example polyols which can then advantageously be used for the synthesis of smooth polyurethanes, smooth polyurethanes being generally and most often intended for coatings, such as glues, coatings, paints and adhesives. Smooth polyurethanes are usually obtained by reaction of said polyols with isocyanates. It is indeed important, often sought, even essential, to prevent the water present in these polyols from reacting with the isocyanate to form carbon dioxide (CO2) and thus create gas bubbles, or even a foam.

[0003] Thus, patent US6051647, for example, seeks to improve the pot life and therefore the effectiveness of a 3A zeolite. This document describes a mild acid treatment of a 3A zeolite, in order to modify its pH and thus minimize the effect of this 3A zeolite when it is used as a desiccant for the manufacture of polyurethane (PU) for smooth coatings, i.e. free from foaming phenomena. In this document, a 50 / 50 mixture of zeolite crystals and castor oil is used, previously prepared to dry the polyol.

[0004] One of the problems encountered with such desiccant compositions concerns their low stability over time; in fact, the zeolite crystals present in these organic compositions have a more or less pronounced tendency to sediment. The desiccant composition is then no longer homogeneous, unless the said zeolite crystals are resuspended. In addition to the fact that this requires an additional mixing step, it may also be necessary to work under an inert atmosphere, in order to avoid any risk of contamination by humidity in the ambient air. All of this results in additional implementation complexities, responsible for increased costs and energy consumption.

[0005] Patents US8026307 and US8153042 mention the use of phyllosilicates for two-component resins to prevent slump of the shapes prepared using said resins. However, these patents do not mention the use of compositions intended to introduce zeolites into the components of the resins.

[0006] In patent CN102814167, an activated molecular sieve powder in paste form is proposed, obtained by mixing 48% to 52% by mass of activated synthetic molecular sieve powder, 30% to 52% by mass of castor oil and 0 to 20% by mass of a viscosity adjusting agent, generally chosen from glycols. The teaching of this document is that the viscosity adjusting agent is between 8% and 20%, values ​​which are very high and can be detrimental to the quality of the desired product.

[0007] The prior art set out above demonstrates that there is currently no fully satisfactory solution for stabilizing a significant quantity of zeolite crystals in a hydroxylated oil in order to limit the sedimentation of said crystals.

[0008] The objective of the present invention is to provide a solution to the problems encountered in the prior art and in particular to provide stable organic compositions comprising zeolite crystals, and in particular stable polyol compositions comprising zeolite crystals having the function of drying and desiccating said compositions.

[0009] Another objective is to provide stable liquid compositions of zeolites for drying organic compounds, in particular for drying organic compounds intended for the preparation of 2K resins, and especially for drying organic compounds intended for the preparation of PU resins.

[0010] The inventors have now discovered that the above-mentioned objectives can be achieved in whole or at least in part by means of the invention which will now be described.

[0011] Thus, a first object of the present invention relates to a composition comprising: - from 30% to 70%, preferably from 40% to 60%, by weight relative to the total weight of the composition, of at least one hydroxylated oil, - from 70% to 30%, preferably from 60% to 40%, by weight relative to the total weight of the composition, of crystals of at least one zeolite and, - from 0.1% to 5%, preferably from 0.3% to 1.5%, by weight relative to the total weight of the composition, of at least one dispersing agent, of organophilic phyllosilicate type, it being understood that the sum of the three components of the composition defined above reaches 100%.

[0012] By hydroxylated oil in the sense of the present invention, is meant any fatty organic compound comprising at least one hydroxyl function, and for example hydroxylated fatty acid esters, such as for example mono-, di- and tri-glycerides, alone or in mixtures of two or more of them. According to one embodiment of the invention, the hydroxylated oil is chosen from mono-, di-, tri-, and poly-hydroxylated oils, alone or in a mixture of two or more of them.

[0013] As non-limiting examples of hydroxylated oils suitable for use in the composition of the invention, mention may be made of castor oil naturally possessing hydroxyl functions. It is also possible to envisage the use of any other type of hydroxylated oil or mixtures of hydroxylated oils, obtained from vegetable, animal or mineral oils, such as for example from soybean, palm, sunflower, olives, and others.

[0014] The composition according to the present invention also comprises crystals of at least one zeolite. Zeolites are mineral compounds well known to those skilled in the art and may be natural, artificial or synthetic zeolites. Zeolites are crystallized aluminosilicates, the crystalline structure of which depends, among other things, on the silicon / aluminum (Si / Al) molar ratio.

[0015] The zeolites, in the form of crystals, which can be used in the context of the present invention can be of any type. By way of non-limiting example, the zeolites are chosen from zeolites of the LTA, FAU, MFI, CHA, SOD, GIS, MOR, RHO, EMT, LTL type, preferably from zeolites of the LTA, FAU and MFI type and more preferably from zeolites of the LTA and FAU type. Alternatively, the zeolites are chosen from zeolites of the MFI type. As already indicated previously, the composition of the present invention can comprise crystals of one or more zeolites, depending on the desired effect.

[0016] The zeolite crystals used in the context of the present invention have advantageously previously undergone one or more treatments aimed at reducing the residual water content, or even eliminating free and absorbed water, or even eliminating any organic structuring agents used during the synthesis of said crystals. Such treatments are perfectly known to those skilled in the art and include heat treatments, vacuum degassing, vacuum desorption, and others. The residual water content of the zeolite crystals used in the invention is determined by the Karl Fischer method. Zeolite crystals having a residual water content of less than 1% by weight are preferred.

[0017] According to a preferred embodiment, said at least one zeolite of the composition of the present invention is chosen from LTA and FAll-X type zeolites, and among these, those whose Si / AI molar ratio is between 1.0 and 1.5, inclusive, are preferred.

[0018] According to another embodiment, said at least one zeolite of the composition of the present invention is chosen from zeolites 3A, 4A, 5A, 13X. According to another embodiment, said at least one zeolite of the composition of the present invention is chosen from MFIs, in particular zeolites of the Silicalite-1 type.

[0019] The size of the zeolite crystal(s) can vary greatly. However, for the purposes of the present invention, zeolite crystals with a size between 0.1 pm and 5 pm, preferably between 0.5 pm and 4 pm, inclusive, are preferred. The size of the crystals corresponds to the number-average diameter, calculated from counting on scanning electron microscopy (SEM) images.

[0020] The composition according to the present invention is characterized by the fact that it comprises at least one dispersing agent. Without wishing to be bound by theory, the dispersing agent promotes and / or makes it possible to maintain the zeolite crystals in suspension in the hydroxylated oil. Said at least one dispersing agent used in the composition of the present invention is an organophilic phyllosilicate.

[0021] Phyllosilicates are natural or synthetic minerals of the silicate group constructed by stacking tetrahedral layers, where the tetrahedra share three out of four vertices, the fourth vertex being connected to an octahedral layer occupied by different cations, for example aluminum, magnesium, iron, titanium, lithium, and others.

[0022] The phyllosilicates that can be used to form the organophilic phyllosilicates that are the composition dispersing agents of the present invention can be of any type and in particular natural clays in general, among which may be mentioned bentonites, palygorskites, sepiolites, attapulgites, montmorillonites, hydrotalcites, octasilicates, and others and mixtures of two or more of them in all proportions. According to a preferred embodiment, the phyllosilicate is chosen from fibrous clays and preferably from hormites, the main representatives of which are sepiolite and attapulgite (or palygorskite). Sepiolite and attapulgite are the preferred hormites in the context of the present invention, and most preferably the preferred phyllosilicate is sepiolite.

[0023] Organophilic phyllosilicates, also called "organoclays" in English, are generally prepared from natural phyllosilicates which are modified by one or more chemical treatments, generally using an organic compound, most often of the surfactant type, for example nitrogenous surfactant, to make them organophilic, as described for example in application WO1999042518. Among the organic compounds capable of modifying the phyllosilicates which can be used in the context of the present invention, cationic surfactants are preferred, among which we can notably cite quaternary ammonium type compounds, as described for example in US20200181474.

[0024] According to a preferred embodiment of the invention, said at least one dispersing agent is an organophilic phyllosilicate chosen from bentonites, palygorskites, sepiolites, attapulgites, montmorillonites, hydrotalcites, octasilicates, and preferably chosen from hormites, among which sepiolite is preferred, said organophilic phyllosilicate being surface functionalized with one or more compounds chosen from amines, surfactants, silanes, siloxanes and alkyl chains. Mixtures of one or more organophilic phyllosilicates may be used in the composition of the present invention. More preferably, said at least one dispersing agent is a fibrous clay or a mixture of fibrous clays modified by one or more surfactants.

[0025] Organophilic phyllosilicates are well known to those skilled in the art and are already widely used in many fields of application; representatives of these compounds are, for example, marketed by the company BYK under the general names TIXOGEL®, CLAYTON® or GARAMITE®.

[0026] It has been discovered, quite surprisingly, that the presence of at least one dispersing agent of organophilic phyllosilicate type makes it possible to significantly limit the sedimentation of zeolite crystal(s) present in a hydroxylated oil, in particular when said crystals are present in an amount greater than 30%, preferably greater than 40%, preferably greater than 50%, by weight, limits included, even after several months of storage.

[0027] The advantages linked to this strong limitation, or even absence, of sedimentation present very numerous advantages among which we can notably cite the absence of need for re-dispersion of the zeolite adsorbent crystals in the oil, which would have the effect of putting the oil back into contact with the ambient air charged with a greater or lesser quantity of water vapor which could contaminate the dispersion. As a result, the composition of the invention is consequently entirely advantageous in numerous fields of application. For example, the composition of the present invention allows polyurethane manufacturers to use the composition (oil hydroxylated / zeolite crystals) in their formulation, without the need to redisperse the zeolite crystals in the oil.

[0028] The composition described in this invention can be prepared by any means known per se, and for example by simple mixing of its different constituents together. According to a preferred embodiment, the zeolite crystals are added to the hydroxylated oil with high-speed shear stirring, for example of the order of 1500 rpm, using a shear stirrer, for example of the Rayneri type, then, still with stirring, the dispersing agent is added. The dispersing agent can advantageously be added in the form of a mixture in an oil, for example the hydroxylated oil of the composition of the invention.

[0029] After complete homogenization of the mixture of constituents, the composition can advantageously be degassed, in order to eliminate the air bubbles trapped during its preparation, by any means known per se, and for example by slight heating (for example between 40°C and 80°C) under partial vacuum, for example under 0.2 bar (0.2 kPa). This degassing step is advantageously carried out with stirring, preferably low stirring, for example of the order of 200 rpm), until complete or almost complete degassing. The composition according to the invention is then in the form of a homogeneous paste, with zeolite crystals in suspension and well dispersed.

[0030] According to a second aspect, the invention relates to the use of the composition as just defined for drying organic compounds, compositions or solutions. According to a very particularly preferred aspect, the invention relates to the use of the composition as just defined for drying organic compositions intended for the preparation of 2K resins, and more particularly still for drying organic compositions intended for the preparation of polyurethane resins.

[0031] Finally, and according to a particularly advantageous aspect, the composition of the present invention finds a use which is entirely suitable for the drying of polyol compositions intended for the preparation of polyurethane resins.

[0032] As indicated above, the composition according to the invention exhibits a completely surprising stability, without sedimentation, or at least without excessive sedimentation, during transport and storage in a pot, for periods of up to one month, or even up to two months, or even up to three months and even up to 4 months or more.

[0033] The time from which the sedimentation of zeolite crystals in the hydroxylated oil is observed can be determined by an accelerated test carried out in a centrifuge. The percentage of decantation of zeolite crystals in the paste is measured by calculating the ratio of apparent hydroxylated oil height to total height of the mixture.

[0034] The invention will now be illustrated with the aid of the following examples without, however, limiting the scope of protection defined by the appended claims. The physical properties, methods and analytical tests described in the examples are evaluated by methods known to those skilled in the art, the main ones of which are recalled below. CHARACTERIZATION TECHNIQUES

[0035] The estimation of the number-average diameter of zeolite crystals is carried out by observation with a Scanning Electron Microscope (SEM). In order to estimate the size of zeolite crystals on the samples, a set of images is taken at a magnification of at least 5000. The diameter of at least 200 crystals is then measured using dedicated software, for example the Smile View software from the LoGraMi publisher. The accuracy is around 3%.

[0036] In the following examples, several organophilic phyllosilicates of different natures were evaluated for their dispersing properties. All compositions of zeolite crystals in a hydroxylated oil are prepared and evaluated according to Example 1 below. Example 1: Test without dispersing agent

[0037] A mixture is prepared containing 50% by weight of zeolite crystals and 50% by weight of hydroxylated oil. For this purpose, 250 g of SA 1720 SC zeolite crystals (zeolite type 3A, marketed by Arkema) with a particle size dso = 2.5 pm (number average diameter) are introduced into 250 g of castor oil, under shear stirring, at high speed, using a Rayneri type mixer at 1500 rpm, in a plastic pot. A homogeneous paste of approximately 500 g is obtained. In order to eliminate air bubbles trapped in the paste during its preparation, it is heated to 60°C under vacuum (0.2 kPa) with gentle stirring (200 rpm) for 1 hour. A homogeneous paste with suspended and well-dispersed crystals is obtained.

[0038] In order to evaluate the duration from which the sedimentation of zeolite crystals in castor oil is observed, an accelerated test is carried out in a Sigma brand centrifuge model 6K15. To do this, 3 bottles containing 140 g of paste are distributed in the centrifuge and rotated at 3000 RCF (Relative Centrifugal Force) for 30 min. The decantation of zeolite crystals in the paste is measured by calculating the ratio of the apparent oil height in mm / total height of the mixture in mm and given as a percentage. The sedimentation rate of this composition without dispersing agent is 18%.

[0039] In Examples 2 to 9, dispersing agents of different natures are evaluated. All compositions of the following examples are prepared and evaluated in the same way. The results are collected in Table 1 appearing later in the description. Example 2: composition according to the invention

[0040] A composition is prepared as described above in Example 1. A mixture is prepared containing 49.75% by weight of zeolite crystals and 49.75% by weight of hydroxylated oil, to which 0.5% of dispersing agent is added. For this purpose, 250 g of zeolite from Example 1 are introduced into 125 g of castor oil, under shear stirring, at high speed, using a Rayneri type mixer at 1500 rpm, in a plastic pot. Then, 2.51 g of dispersing agent, previously dispersed in 125 g of castor oil, is added under stirring for 30 min. The dispersing agent is an organophilic montmorillonite, marketed under the reference CLAYTON® AF by the company BYK.

[0041] A homogeneous paste of approximately 502.5 g is obtained. In order to eliminate air bubbles trapped in the paste during its preparation, it is heated to 60°C under vacuum (0.2 kPa) with gentle stirring (200 rpm) for 1 hour. A homogeneous paste with suspended and well-dispersed crystals is obtained. The sedimentation rate of the Composition of Example 2 is 8.9%. Example 3: according to the invention

[0042] In this example, where the composition is prepared as in Example 2, the dispersing agent is an organophilic montmorillonite marketed under the reference Tixogel® MP 250 by the company BYK. The sedimentation rate is 8.0%. Example 4: according to the invention

[0043] This Composition is also prepared as in Example 2, the dispersing agent being replaced by an organophilic sepiolite marketed under the reference Garamite® 1958 by the company BYK. The sedimentation rate is 6.9%. Example 5: comparative example:

[0044] This Composition is prepared according to Example 2, with as dispersing agent a dispersing agent of the modified polyglycol polyalkylene imine polyester type, marketed under the reference BYK® 2155 by the company BYK. The observed sedimentation rate is 11.9%. Example 6: comparative example:

[0045] In this Composition, prepared as in Example 2, the dispersing agent is this time a copolymer type dispersing agent functionalized with acid groups, and marketed under the reference Disperbyk® 111 by the company BYK. The sedimentation rate is then 22%. Example 7: comparative example:

[0046] Still preparing the composition according to the protocol of example 2, the composition of this example contains a dispersing agent which is a modified urea solution, marketed under the reference Disperbyk® 7410 by the company BYK. The sedimentation rate is then 13%. Example 8: comparative example:

[0047] The Composition of Comparative Example 8 is prepared according to the protocol of Example 2 with a high molecular weight polyacrylic type dispersing agent, marketed under the reference BYK® 430 by the company BYK. The sedimentation rate is 12.1%. Example 9: comparative example:

[0048] In this comparative example, the Composition is prepared according to the protocol of Example 2 with an unmodified sepiolite type clay, marketed under the reference P400 by the company Toisa. The sedimentation rate is 17.5%.

[0049] The full results are reported in Table 1 below. -- Table 1 --

[0050] The above results clearly show that organophilic phyllosilicate dispersing agents can substantially reduce the sedimentation rate of zeolite crystal compositions dispersed in a hydroxylated oil. Conversely, when the dispersing agent is a dispersant other than an organophilic phyllosilicate, sedimentation becomes significant or even problematic and may require re-homogenization before use.

Claims

CLAIMS 1. Composition comprising: - from 30% to 70%, preferably from 40% to 60%, by weight relative to the total weight of the composition, of at least one hydroxylated oil, - from 70% to 30%, preferably from 60% to 40%, by weight relative to the total weight of the composition, of crystals of at least one zeolite and, - from 0.1% to 5%, preferably from 0.3% to 1.5%, by weight relative to the total weight of the composition, of at least one dispersing agent of organophilic phyllosilicate type, it being understood that the sum of the three components of the composition defined above reaches 100%.

2. Composition according to claim 1, in which the hydroxylated oil is a di-, tri-, or poly-hydroxylated oil, alone or as a mixture of two or more of them.

3. Composition according to claim 1 or claim 2, in which the hydroxylated oil is a hydroxylated oil or a mixture of hydroxylated oils, obtained from vegetable, animal or mineral oils, and preferably the hydroxylated oil is castor oil.

4. Composition according to any one of the preceding claims, in which said at least one zeolite is chosen from zeolites of the LTA, FAll, MFI, CHA, SOD, GIS, MOR, RHO, EMT, LTL type, preferably from zeolites of the LTA, FAll and MFI type and more preferably from zeolites of the LTA, FAU and MFI type.

5. Composition according to any one of the preceding claims, in which said at least one zeolite is chosen from LTA type and FAU-X type zeolites, preferably whose Si / AI molar ratio is between 1.0 and 1.5, limits inclusive.

6. Composition according to any one of the preceding claims, in which said at least one zeolite is chosen from zeolites 3A, 5A and 13X.

7. Composition according to any one of the preceding claims, in which the zeolite crystals have a number-average diameter, calculated from counting on scanning electron microscopy (SEM) images, of between 0.1 pm and 5 pm, preferably between 0.5 pm and 4 pm.

8. Composition according to any one of the preceding claims, in which the dispersing agent is an organophilic phyllosilicate chosen from bentonites, palygorskites, sepiolites, attapulgites, montmorillonites, hydrotalcites, octasilicates, and preferably chosen from hormites, among which sepiolite is preferred, said organophilic phyllosilicate being surface functionalized with one or more compounds chosen from amines, surfactants, silanes, siloxanes and alkyl chains.

9. Composition according to any one of the preceding claims, in which the dispersing agent is a fibrous clay or a mixture of fibrous clays modified by one or more surfactants.

10. Use of a composition according to any one of the preceding claims, for drying organic compounds, compositions or solutions.

11. Use according to the preceding claim, for drying organic compositions intended for the preparation of 2K resins.

12. Use according to the preceding claim, for the drying of organic compositions intended for the preparation of polyurethane resins.

13. Use according to the preceding claim, for the drying of polyols intended for the preparation of polyurethane resins.

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