Stable organic compositions containing zeolites

Abstract

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

Description

[Technical Field]

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

[0002] Such compositions are often used to dry organic liquids, such as polyols, which can be advantageously used to synthesize smooth polyurethanes, which are usually intended for coatings such as adhesives, coats, and paints. Smooth polyurethanes are usually obtained by reacting the polyols with isocyanates. Specifically, it is important, often desirable, or even essential, to prevent the water present in these polyols from reacting with the isocyanates to form carbon dioxide (CO2), thus producing bubbles or even foam.

[0003] For example, US Patent No. 6,051,647 attempts to improve the pot life and, consequently, the effectiveness of zeolite 3A. This document describes a mild acidic treatment of zeolite 3A to modify its pH and thus minimize its effectiveness when used as a drying agent in polyurethane (PU) production for smooth, i.e., foam-free, coatings. This document dries polyols using a 50 / 50 mixture of pre-prepared zeolite crystals and castor oil.

[0004] One of the problems encountered with such desiccant compositions is their poor stability over time; in particular, the zeolite crystals present in these organic compositions have a more or less pronounced tendency to settle. The desiccant composition is then no longer homogeneous unless the zeolite crystals are resuspended. Apart from the fact that this requires an additional mixing step, it may also be necessary to work under an inert atmosphere to avoid the risk of contamination by moisture in the ambient air. All this is reflected in additional packaging complexity, resulting in increased costs and energy consumption.

[0005] Patents US8026307 and US8153042 describe the use of phyllosilicates in two-component resins to prevent the collapse of shapes prepared with the resins, but these patents do not mention the use of compositions intended to incorporate zeolites into the resin components.

[0006] Patent document CN102814167 proposes a paste-like molecular sieve active powder obtained by mixing 48% to 52% by weight of synthetic molecular sieve active powder, 30% to 52% by weight of castor oil, and 0% to 20% by weight of a viscosity modifier usually selected from glycols. This document teaches that the viscosity modifier is present between 8% and 20%, a value that is too high and may impair the quality of the desired product.

[0007] The above-mentioned prior art demonstrates that today there are no entirely satisfactory solutions for stabilizing significant amounts of zeolite crystals in hydroxylated oils in order to limit the settling of said crystals. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] U.S. Patent No. 6,051,647 [Patent Document 2] U.S. Patent No. 8,026,307 [Patent Document 3] U.S. Patent No. 8,153,042 [Patent Document 4] Chinese Patent No. 102814167 Summary of the Invention [Problem to be solved by the invention]

[0009] The object of the present invention is to provide a solution to the problems encountered in the prior art, in particular to provide a stable organic composition comprising zeolite crystals, in particular a stable polyol composition comprising zeolite crystals that have a drying, desiccating function for the composition.

[0010] Another object is to provide a stable liquid zeolite composition for drying organic compounds, in particular for drying organic compounds intended for preparing 2K resins, most particularly for drying organic compounds intended for preparing PU resins. [Means for solving the problem]

[0011] The inventors have now discovered that the above objectives may be achieved in whole or at least in part by the invention described herein.

[0012] The first subject of the invention is therefore from 30% to 70% by weight, and preferably from 40% to 60% by weight, of at least one hydroxylated oil relative to the total weight of the composition, - from 70% to 30% by weight, preferably from 60% to 40% by weight, of at least one zeolite crystal, relative to the total weight of the composition; and - from 0.1% to 5% by weight, preferably from 0.3% to 1.5% by weight, of at least one dispersant of organophilic phyllosilicate type relative to the total weight of the composition wherein it is understood that the sum of the three components of the composition defined above amounts to 100%. DETAILED DESCRIPTION OF THE INVENTION

[0013] For the purposes of the present invention, the term "hydroxylated oil" is understood to mean any fatty organic compound containing at least one hydroxyl functional group, such as hydroxylated fatty acid esters, such as mono-, di- and triglycerides, alone or in a mixture of two or more. According to one embodiment of the present invention, the hydroxylated oil is selected from mono-, di-, tri- and polyhydroxylated oils, alone or in a mixture of two or more.

[0014] A non-limiting example of hydroxylated oils that can be used in the compositions of the present invention is castor oil, which naturally has hydroxyl functional groups.It is also conceivable to use any other type of hydroxylated oil or mixture of hydroxylated oils obtained from vegetable, animal or mineral oils, such as soybean, palm, sunflower, olive, etc.

[0015] The composition according to the invention also contains at least one zeolite crystal. Zeolites are mineral compounds well known to those skilled in the art and can be natural, artificial or synthetic. Zeolites are crystalline aluminosilicates whose crystalline structure depends, inter alia, on the silicon / aluminum (Si / Al) molar ratio.

[0016] The crystalline form of zeolites that can be used in the context of the present invention can be of any type. By way of non-limiting example, the zeolites are selected from LTA, FAU, MFI, CHA, SOD, GIS, MOR, RHO, EMT and LTL type zeolites, preferably from LTA, FAU and MFI type zeolites, more preferably from LTA and FAU type zeolites. In a variant, the zeolites are selected from MFI type zeolites. As already mentioned above, the compositions of the present invention may contain one or more zeolite crystals, depending on the effect sought.

[0017] The zeolite crystals used in the context of the present invention have advantageously been subjected to one or more treatments aimed at reducing the residual water content, or even removing free and adsorbed water, or removing any organic structuring agent used during the synthesis of said crystals. Such treatments are perfectly well known to those skilled in the art and include heat treatment, vacuum degassing, vacuum desorption, etc. The residual water content of the zeolite crystals used in the present invention is determined by the Karl Fischer method. Zeolite crystals having a residual water content of less than 1% by weight are preferred.

[0018] According to a preferred embodiment, the at least one zeolite of the composition of the invention is selected from LTA-type zeolites and FAU-X-type zeolites, among which zeolites having a Si / Al molar ratio between 1.0 and 1.5 (inclusive) are preferred.

[0019] According to yet another embodiment, the at least one zeolite of the composition of the invention is chosen from zeolites 3A, 4A, 5A and 13X. According to another embodiment, the at least one zeolite of the composition of the invention is chosen from zeolites of the MFI, in particular silicalite-1, type.

[0020] The size of the zeolite crystals can vary widely. However, for the purposes of the present invention, zeolite crystals having a size between 0.1 μm and 5 μm, preferably between 0.5 μm and 4 μm (limits included), are preferred. The size of the crystals corresponds to the number-average diameter calculated by counting in scanning electron microscope (SEM) images.

[0021] The compositions of the present invention are characterized by the fact that they contain at least one dispersant. Without wishing to be bound by theory, the dispersant promotes and / or makes it possible to keep the zeolite crystals in suspension in the hydroxylated oil. The at least one dispersant used in the compositions of the present invention is an organophilic phyllosilicate.

[0022] Phyllosilicates are natural or synthetic minerals from the silicate group, constructed by stacking of tetrahedral layers, where the tetrahedra share three of their four vertices and the fourth vertex is connected to an octahedral layer occupied by a different cation, such as aluminum, magnesium, iron, titanium, lithium, etc.

[0023] The phyllosilicates that can be used to form the organophilic phyllosilicates that are dispersants in the compositions of the present invention can be of any type, and in particular can be generally natural clays, including bentonite, palygorskite, sepiolite, attapulgite, montmorillonite, hydrotalcite, octasilicates, etc., and mixtures of two or more of them in any proportion. According to a preferred embodiment, the phyllosilicates are selected from fibrous clays, preferably from formites, the main representatives of which are sepiolite and attapulgite (or palygorskite). Sepiolite and attapulgite are preferred formites in the context of the present invention, and the preferred phyllosilicates are entirely preferred sepiolite.

[0024] Organophilic phyllosilicates, also known as organoclays, are generally prepared from natural phyllosilicates that have been modified by one or more chemical treatments to make them organophilic, typically using organic compounds, usually surfactant-type, such as nitrogen-containing surfactants, as described, for example, in patent application WO1999042518. Among the organic compounds suitable for modifying phyllosilicates that can be used in the context of the present invention, cationic surfactants are preferred, and among them, quaternary ammonium type compounds, for example, as described in US20200181474, can be mentioned in particular.

[0025] According to a preferred embodiment of the present invention, the at least one dispersing agent is an organophilic phyllosilicate selected from bentonite, palygorskite, sepiolite, attapulgite, montmorillonite, hydrotalcite, and octasilicates, preferably from formite, with sepiolite being preferred, and the organophilic phyllosilicate is surface-functionalized with one or more compounds selected from amines, surfactants, silanes, siloxanes, and alkyl chains. A mixture of one or more organophilic phyllosilicates can be used in the composition of the present invention. More preferably, the at least one dispersing agent is a fibrous clay or a mixture of fibrous clays modified with one or more surfactants.

[0026] Organophilic phyllosilicates are well known to those skilled in the art and are already widely used in many fields of application. Representative examples of these compounds are sold, for example, by the company BYK under the trade names TIXOGEL®, CLAYTONE® or GARAMITE®.

[0027] Completely surprisingly, it has been discovered that the presence of at least one organophilic phyllosilicate type dispersant makes it possible to significantly limit the sedimentation of zeolite crystals present in hydroxylated oils, especially when said crystals are present in amounts of more than 30% by weight, preferably more than 40% by weight, preferably more than 50% by weight (limits included), even after storage for several months.

[0028] The advantages associated with this significant limitation or even absence of sedimentation provide numerous advantages, among which can be mentioned the absence of the need to redisperse the zeolite adsorbent crystals in the oil, which would involve contacting the oil with ambient air containing a more or less significant amount of water vapor, which may contaminate the dispersion.As a result, the composition of the present invention is absolutely advantageous in many application fields.For example, the composition of the present invention allows polyurethane manufacturers to use the composition (hydroxylated oil / zeolite crystals) in formulations without the need to redisperse the zeolite crystals in the oil.

[0029] The composition described in the present invention can be prepared by any known means, for example, by simply mixing its various components together.According to a preferred embodiment, zeolite crystals are added to hydroxylated oil while shear stirring, for example, using a Rayneri type shear stirrer, at a high speed, for example, about 1500 rpm, and then, while still stirring, dispersant is added.Dispersant can advantageously be added in the form of a mixture in oil, for example, hydroxylated oil of the composition of the present invention.

[0030] After the mixture of components has been thoroughly homogenized, the composition can be advantageously degassed by any means known per se, for example by gentle heating (for example, between 40°C and 80°C) under partial vacuum, for example at 0.2 bar (0.2 kPa), in order to remove any air bubbles trapped during the preparation of the composition. This degassing step is advantageously carried out under stirring, preferably gentle stirring, for example at around 200 rpm, until complete or virtually complete degassing is achieved. The composition according to the invention is thus in the form of a homogeneous paste with suspended and well-dispersed zeolite crystals.

[0031] According to a second aspect, the present invention relates to the use of the composition just defined for drying organic compounds, compositions or solutions. According to a most particularly preferred aspect, the present invention relates to the use of the composition just defined for drying organic compositions intended for preparing 2K resins, more particularly for drying organic compositions intended for preparing polyurethane resins.

[0032] Finally, according to a particularly advantageous embodiment, the compositions of the invention are perfectly suitable for use in drying polyol compositions intended to prepare polyurethane resins.

[0033] As previously shown, the compositions according to the invention exhibit quite surprising stability during transport and storage in the container without sedimentation, or at least without excessive sedimentation, for periods lasting up to one month, or even up to two months, or even up to three months, and even up to four months or more.

[0034] The time at which the sedimentation of zeolite crystals in the hydroxylated oil is observed can be determined by accelerated tests carried out in a centrifuge. The sedimentation rate of the zeolite crystals in the paste is measured by taking the ratio of the apparent height of the hydroxylated oil to the total height of the mixture. [Example]

[0035] The invention will now be illustrated by the following examples, without limiting the scope of protection defined by the appended claims. The physical properties, methods and analytical tests described in the examples were evaluated by methods known to those skilled in the art, the main parts of which are repeated below.

[0036] <Characterization Technology> The number-average diameter of zeolite crystals is estimated by observation using a scanning electron microscope (SEM). To estimate the size of the zeolite crystals in a sample, a set of images is taken at a magnification of at least 5000. The diameters of at least 200 crystals are then measured using dedicated software, such as the Smile View software published by LoGraMi. The accuracy is approximately 3%.

[0037] In the following examples, several organophilic phyllosilicates of various natures were evaluated for their dispersing properties. All compositions of zeolite crystals in hydroxylated oil were prepared and evaluated according to Example 1 below.

[0038] [Example 1] Test without dispersant A mixture containing 50% by weight of zeolite crystals and 50% by weight of hydroxylated oil is prepared. 50250 g of SA 1720 SC zeolite crystals (type 3A zeolite, sold by Arkema) with a particle size of 2.5 μm (number average diameter) are introduced into 250 g of castor oil in a plastic pot with rapid shear stirring at 1500 rpm using a Rayneri mixer. Approximately 500 g of homogeneous paste is obtained. To remove air bubbles trapped in the paste during its preparation, the paste is heated at 60° C. for 1 hour under gentle stirring (200 rpm) and vacuum (0.2 kPa). A homogeneous paste with suspended and well-dispersed crystals is obtained.

[0039] To evaluate the time until the sedimentation of zeolite crystals in castor oil is observed, an accelerated test is carried out in a Sigma 6K15 model centrifuge. To do this, three flasks containing 140 g of paste are distributed into the centrifuge and spun at 3000 RCF (relative centrifugal force) for 30 minutes. The sedimentation of zeolite crystals in the paste is measured by taking the ratio of the apparent oil height in mm to the total height of the mixture in mm, and is given as a percentage. The sedimentation rate of this composition without dispersant is 18%.

[0040] In Examples 2-9, dispersants of various nature are evaluated. All of the compositions of the following examples are similarly prepared and evaluated. The results are summarized in Table 1, which appears later in the specification.

[0041] [Example 2] Composition according to the present invention The composition is prepared as described above in Example 1. A mixture containing 49.75% by weight of zeolite crystals and 49.75% by weight of hydroxylated oil is prepared, to which 0.5% of dispersant is added. For this purpose, 250 g of the zeolite from Example 1 is introduced into 125 g of castor oil in a plastic pot with rapid shear stirring at 1500 rpm using a Rayneri mixer. Then, 2.51 g of dispersant, previously dispersed in 125 g of castor oil, is added while stirring for 30 minutes. The dispersant is organophilic montmorillonite sold by BYK under the reference name CLAYTONE® AF.

[0042] Approximately 502.5 g of a homogeneous paste is obtained. To remove air bubbles trapped in the paste during its preparation, the paste is heated at 60°C for 1 hour under vacuum (0.2 kPa) with gentle stirring (200 rpm). A homogeneous paste with suspended and well-dispersed crystals is obtained. The sedimentation degree of the composition of Example 2 is 8.9%.

[0043] [Example 3] According to the present invention In this example, the composition is prepared as in Example 2, and the dispersant is an organophilic montmorillonite sold by the company BYK under the reference TIXOGEL® MP250. The sedimentation degree is 8.0%.

[0044] [Example 4] According to the present invention This composition is also prepared similarly to Example 2, but the dispersant is replaced by organophilic sepiolite sold by the company BYK under the reference GARAMITE® 1958. The sedimentation degree is 6.9%.

[0045] [Example 5] Comparative Example This composition is prepared according to Example 2, using as dispersant a dispersant of the modified polyalkylenimine polyglycol polyester type sold by the company BYK under the reference BYK® 2155. The observed degree of sedimentation is 11.9%.

[0046] [Example 6] Comparative Example In this composition, prepared as in Example 2, the dispersant is an acid-functionalized copolymer type dispersant sold by the company BYK under the reference DISPERBYK® 111. The sedimentation degree is 22%.

[0047] [Example 7] Comparative Example The composition is still prepared according to the protocol of Example 2, this example composition containing a dispersant which is a modified urea solution sold by the company BYK under the reference DISPERBYK® 7410. The degree of sedimentation is 13%.

[0048] [Example 8] Comparative Example The composition of Comparative Example 8 is prepared according to the protocol of Example 2, using a high molecular weight polyacrylic type dispersant sold by the company BYK under the reference BYK® 430. The sedimentation degree is 12.1%.

[0049] [Example 9] Comparative Example In this comparative example, a composition is prepared according to the protocol of example 2, using an unmodified sepiolite type clay sold under the reference P400 by the company Tolsa. The degree of settling is 17.5%.

[0050] All of the results are summarized in Table 1 below.

[0051] [Table 1]

[0052] These results clearly demonstrate that organophilic phyllosilicate-type dispersants can substantially reduce the degree of settling of compositions of zeolite crystals dispersed in hydroxylated oils. In contrast, when the dispersant is a dispersant other than an organophilic phyllosilicate, settling can be significant or even problematic, requiring rehomogenization before use.

Claims

1. 1. A composition comprising: from 30% to 70% by weight, and preferably from 40% to 60% by weight, of at least one hydroxylated oil relative to the total weight of the composition, - from 70% to 30% by weight, preferably from 60% to 40% by weight, of at least one zeolite crystal, relative to the total weight of the composition; and from 0.1% to 5% by weight, preferably from 0.3% to 1.5% by weight, relative to the total weight of the composition, of at least one dispersant of organophilic phyllosilicate type wherein it is understood that the sum of the three components of the composition defined above amounts to 100%.

2. 2. The composition of claim 1, wherein the hydroxylated oil is a di-, tri-, or polyhydroxylated oil, either alone or in combination.

3. 3. The composition according to claim 1 or 2, wherein the hydroxylated oil is a hydroxylated oil or a mixture of hydroxylated oils obtained from a vegetable, animal or mineral oil, preferably the hydroxylated oil is castor oil.

4. 4. The composition according to any one of claims 1 to 3, wherein the at least one zeolite is selected from LTA, FAU, MFI, CHA, SOD, GIS, MOR, RHO, EMT and LTL type zeolites, preferably from LTA, FAU and MFI type zeolites, more preferably from LTA, FAU and MFI type zeolites.

5. 5. The composition according to any one of claims 1 to 4, wherein said at least one zeolite is selected from LTA-type zeolites and FAU-X-type zeolites, the Si / Al molar ratio of which is preferably between 1.0 and 1.5, inclusive.

6. 6. The composition according to any one of claims 1 to 5, wherein the at least one zeolite is selected from zeolites 3A, 5A and 13X.

7. 7. The composition according to any one of claims 1 to 6, wherein the zeolite crystals have a number average diameter, calculated by counting in a scanning electron microscope (SEM) image, of between 0.1 μm and 5 μm, preferably between 0.5 μm and 4 μm.

8. 8. A composition according to any one of claims 1 to 7, wherein the dispersing agent is an organophilic phyllosilicate selected from bentonite, palygorskite, sepiolite, attapulgite, montmorillonite, hydrotalcite, octasilicates, preferably formite, of which sepiolite is preferred, the organophilic phyllosilicate being surface functionalized with one or more compounds selected from amines, surfactants, silanes, siloxanes and alkyl chains.

9. A composition according to any one of claims 1 to 8, wherein the dispersing agent is a fibrous clay or a mixture of fibrous clays modified with one or more surfactants.

10. Use of a composition according to any one of claims 1 to 9 for drying organic compounds, compositions or solutions.

11. 11. Use according to claim 10 for drying organic compositions intended to prepare 2K resins.

12. 12. Use according to claim 11 for drying organic compositions intended to prepare polyurethane resins.

13. 13. Use according to claim 12 for drying polyols intended for preparing polyurethane resins.

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