Stable organic composition comprising zeolite

Abstract

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

Description

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

[0002] Such compositions are generally and most commonly used for drying organic liquids and, for example, polyols, which can then be advantageously used for the synthesis of smooth polyurethanes, which are generally and most commonly used in coatings such as adhesives, coatings and paints. Smooth polyurethanes are generally obtained by reacting said polyols with isocyanates. Specifically, it is important, generally desirable or even indispensable to prevent the water present in these polyols from reacting with the isocyanate to form carbon dioxide (CO2) and thus to produce bubbles or even foam.

[0003] For example, patent US6051647, for example, seeks to improve the pot life and thus the efficacy of zeolite 3A. This document describes a mild acid treatment of zeolite 3A to change its pH value so as to minimize the impact of this zeolite 3A when it is used as a dehydrating agent for the manufacture of polyurethanes (PU) for smooth coatings, i.e., coatings without foaming phenomena. This document uses a 50 / 50 mixture of pre-prepared zeolite crystals and castor oil to dry the polyols.

[0004] One of the problems faced by such dehydrating agent compositions relates to their low stability over time; specifically, the zeolite crystals present in these organic compositions have a more or less marked tendency to settle. Subsequently, the dehydrating agent composition is no longer homogeneous unless the 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 to avoid any risk of contamination by moisture in the ambient air. All of this is reflected in an additional implementation complexity, which is the cause of increased costs and energy consumption.

[0005] Patents US8026307 and US8153042 mention the use of layered silicates in two-component resins to avoid the collapse of shaped bodies prepared using said resins. However, these patents do not mention the use of compositions intended to introduce zeolites into the resin component.

[0006] Patent CN102814167 proposes a paste-like molecular sieve activation powder, which is obtained by mixing 48% to 52% by mass of a synthetic molecular sieve activation powder, 30% to 52% by mass of castor oil and 0% to 20% by mass of a viscosity regulator generally selected from diols. This document teaches that the viscosity regulator is present at 8% to 20%, a value that is very high and may impair the quality of the desired product.

[0007] The above-mentioned prior art shows that, so far, there has been no completely satisfactory solution to stabilizing a large amount of zeolite crystals in hydroxylated oils to limit the sedimentation of said crystals.

[0008] The object of the present invention is to provide a solution to the problems encountered in the prior art, and in particular to provide a stable organic composition containing zeolite crystals, and in particular a stable polyol composition containing zeolite crystals, which has the function of drying and dehydrating said composition.

[0009] Another object is to provide a stable liquid zeolite composition which is used for drying organic compounds, in particular for drying organic compounds used in the preparation of 2K resins, and most particularly for drying organic compounds used in the preparation of PU resins.

[0010] The inventors have now found that, by means of the present invention which will now be described, the above objects can be achieved completely or at least partially.

[0011] Accordingly, a first subject of the present invention relates to a composition which comprises:

[0012] - at least one hydroxylated oil in an amount of 30% to 70% by weight, preferably 40% to 60% by weight, relative to the total weight of the composition,

[0013] - crystals of at least one zeolite in an amount of 70% to 30% by weight, preferably 60% to 40% by weight, relative to the total weight of the composition, and

[0014] - at least one organophilic lamellar silicate type dispersant in an amount of 0.1% to 5% by weight, preferably 0.3% to 1.5% by weight, relative to the total weight of the composition,

[0015] It should be understood that the sum of the three components of the composition defined above amounts to 100%.

[0016] 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, and for example hydroxylated fatty acid esters such as, for example, monoglycerides, diglycerides and triglycerides, either alone or as a mixture of two or more of them. According to one embodiment of the present invention, the hydroxylated oil is selected from monohydroxylated oils, dihydroxylated oils, trihydroxylated oils and polyhydroxylated oils, either alone or as a mixture of two or more of them.

[0017] As a non-limiting example of a hydroxylated oil that can be used in the compositions of the present invention, castor oil, which naturally has a hydroxyl functional group, can be mentioned. It is also conceivable to use any other type of hydroxylated oil or a mixture of hydroxylated oils, which are obtained from vegetable oils, animal oils or mineral oils, such as, for example, from soybeans, palm, sunflower, olive, etc.

[0018] The composition according to the present invention further comprises at least one crystal of zeolite. Zeolites are mineral compounds well known to those skilled in the art, and they can be natural zeolites, artificial zeolites or synthetic zeolites. Zeolites are crystalline aluminosilicates, and their crystal structure depends in particular on the silicon / aluminum (Si / Al) molar ratio.

[0019] The zeolite in crystal form that can be used in the context of the present invention can be of any type. As non-limiting examples, zeolites are selected from zeolites of the LTA type, FAU type, MFI type, CHA type, SOD type, GIS type, MOR type, RHO type, EMT type and LTL type, preferably selected from zeolites of the LTA type, FAU type and MFI type, and more preferably selected from zeolites of the LTA type and FAU type. In a variant embodiment, the zeolite is selected from zeolites of the MFI type. As described above, depending on the desired effect, the composition of the present invention can comprise one or more crystals of zeolite.

[0020] The zeolite crystals used in the context of the present invention are advantageously pre-treated by one or more processes aimed at reducing the residual water content, or even eliminating free water and adsorbed water, or eliminating any organic structuring agent used in the synthesis of said crystals. Such treatments are 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. Preferably, the zeolite crystals have a residual water content of less than 1% by weight.

[0021] According to a preferred embodiment, the at least one zeolite of the composition of the present invention is selected from zeolites of the LTA type and FAU-X type, and among these zeolites, those with a Si / Al molar ratio of 1.0 to 1.5, including the end points, are preferred.

[0022] According to yet another embodiment, the at least one zeolite of the composition of the present invention is selected from zeolite 3A, zeolite 4A, zeolite 5A and zeolite 13X. According to another embodiment, the at least one zeolite of the composition of the present invention is selected from zeolites of the MFI type, especially Silicalite-1 type.

[0023] The size of the zeolite crystals can vary within a wide range. However, for the purposes of the present invention, the size of the zeolite crystals is preferably from 0.1 μm to 5 μm, more preferably from 0.5 μm to 4 μm, including the endpoints. The size of the crystals corresponds to the number average diameter calculated by counting in a scanning electron microscope (SEM) image.

[0024] The composition according to the invention is characterized in that it comprises at least one dispersant. Without wishing to be bound by theory, the dispersant promotes and / or makes it possible to keep the zeolite crystals suspended in the hydroxylated oil. The at least one dispersant for the composition according to the invention is an organophilic layered silicate.

[0025] The layered silicate is a natural or synthetic mineral from the group of silicates, consisting of a stack of tetrahedral layers, in which the tetrahedra share three of their four vertices, and the fourth vertex is connected to an octahedral layer occupied by different cations, such as aluminum cations, magnesium cations, iron cations, titanium cations, lithium cations, etc.

[0026] The layered silicate that can be used to form the organophilic layered silicate which is the dispersant of the composition according to the invention can be of any type, and in particular the usual natural clays, among which mention may be made of those composed of bentonite, palygorskite, sepiolite, attapulgite, montmorillonite, hydrotalcite, octasilicate, etc., and mixtures of two or more of them in any proportion. According to a preferred embodiment, the layered silicate is selected 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 quite preferably, the preferred layered silicate is sepiolite.

[0027] The organophilic layered silicate, also known as organoclay, is generally prepared from natural layered silicates, which are modified by one or more chemical treatments, usually using organic compounds, generally organic compounds of the surfactant type, such as nitrogen-containing surfactants, as described, for example, in patent application WO1999042518. Among the organic compounds suitable for modifying the layered silicates that can be used in the context of the present invention, cationic surfactants are preferred, among which mention may be made in particular of quaternary ammonium-type compounds, as described, for example, in US20200181474.

[0028] According to a preferred embodiment of the present invention, the at least one dispersant is an organophilic layered silicate selected from bentonite, palygorskite, sepiolite, attapulgite, montmorillonite, hydrotalcite, octosilicate, and preferably selected from the attapulgite group, and preferably sepiolite, and the organophilic layered silicate is surface-functionalized with one or more compounds selected from amines, surfactants, silanes, siloxanes, and alkyl chains. A mixture of one or more organophilic layered silicates can be used in the composition of the present invention. More preferably, the at least one dispersant is a fibrous clay or a mixture of fibrous clays modified with one or more surfactants.

[0029] Organophilic layered silicates are well known to those skilled in the art and have been widely used in many fields of application; representatives of these compounds are sold, for example, by BYK under the common name

[0030] Completely unexpectedly, it has been found that the presence of at least one dispersant of the organophilic layered silicate type makes it possible to greatly limit the settling of the zeolite crystals present in the hydroxylated oil, especially when the crystals are present in an amount greater than 30% by weight, preferably greater than 40% by weight, preferably greater than 50% by weight, including the end points, and even after several months of storage.

[0031] The advantages associated with this greatly limited settling or even the absence of settling provide many benefits, among which it is particularly worth mentioning that there is no need to redisperse the zeolite adsorbent crystals in the oil, which would require contacting the oil with ambient air carrying more or less significant amounts of water vapor that could contaminate the dispersion. Therefore, the composition of the present invention is definitely advantageous in many fields of application. For example, the composition of the present invention allows polyurethane manufacturers to use the composition (hydroxylated oil / zeolite crystals) in their formulations without the need to redisperse the zeolite crystals in the oil.

[0032] The composition described in the present invention can be prepared by any method known per se, for example by simply mixing its various components with each other. According to a preferred embodiment, using a shear stirrer of the Rayneri type, for example, the zeolite crystals are added to the hydroxylated oil under high-speed shear stirring, for example at about 1500 rpm, and then, still under stirring, the dispersant is added. The dispersant can advantageously be added in the form of a mixture in the oil, such as the hydroxylated oil of the composition of the present invention.

[0033] After complete homogenization of the component mixture, the composition can advantageously be degassed to remove the air bubbles entrapped during the preparation of the composition according to any method known per se, for example under partial vacuum, for example at 0.2 bar (0.2 kPa), by gentle heating (for example from 40 °C to 80 °C). This degassing step is advantageously carried out with stirring, preferably gentle stirring, for example stirring at about 200 rpm, until complete or almost complete degassing is achieved. Then, the composition according to the invention is in the form of a homogeneous paste with zeolite crystals suspended and well-dispersed.

[0034] According to a second aspect, the invention relates to the use of the composition as just defined for drying organic compounds, organic compositions or organic solutions. According to the most particularly preferred aspect, the invention relates to the use of the composition as just defined for drying organic compositions for the preparation of 2K resins, more particularly for drying organic compositions for the preparation of polyurethane resins.

[0035] Finally, and according to a particularly advantageous aspect, the composition of the invention is perfectly suitable for drying polyol compositions for the preparation of polyurethane resins.

[0036] As previously mentioned, the composition according to the invention shows a completely unexpected stability, without sedimentation, or at least without excessive sedimentation, during transport and storage in a container for a period 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 than 4 months.

[0037] The time at which zeolite crystal sedimentation in the hydroxylated oil is observed can be determined by an accelerated test carried out in a centrifuge. The sedimentation percentage of 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.

[0038] The invention will now be illustrated by means of the following examples, which, however, do not limit the scope of protection of the invention 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 repeated below.

[0039] Characterization techniques

[0040] The number-average diameter of the zeolite crystals is estimated by observation with a scanning electron microscope (SEM). To estimate the size of the zeolite crystals in the sample, a set of images is acquired at a magnification of at least 5000 times. Then, at least 200 crystal diameters are measured using dedicated software, such as Smile View software published by LoGraMi. The accuracy is about 3%.

[0041] In the following examples, the dispersion properties of several organophilic layered silicates of different properties were evaluated. The compositions of zeolite crystals in all hydroxylated oils were prepared and evaluated according to Example 1 below.

[0042] Example 1: Test without a dispersant

[0043] A mixture containing 50 wt% zeolite crystals and 50 wt% hydroxylated oil was prepared. To this end, 250 g d 50 SA 1720SC zeolite crystals (type 3A zeolite, sold by Arkema) with a particle size = 2.5 μm (number average diameter) were introduced into 250 g of castor oil in a plastic tank, and shear stirring was carried out at a high speed using a Rayneri mixer at a rotation speed of 1500 rpm. Approximately 500 g of a homogeneous paste was obtained. In order to remove the air bubbles entrained in the paste during the preparation process, the paste was heated at 60 °C, under vacuum (0.2 kPa) and gentle stirring (200 rpm) for 1 hour. A homogeneous paste with suspended and well-dispersed crystals was obtained.

[0044] To evaluate the time at which the zeolite crystals were observed to settle in the castor oil, an accelerated test was carried out in a Sigma 6K15 centrifuge. To this end, 3 flasks containing 140 g of the paste were distributed in the centrifuge and set to rotate at 3000 RCF (relative centrifugal force) for 30 minutes. The settling of the zeolite crystals in the paste was measured by the ratio of the apparent oil height in mm / the total height of the mixture in mm and given as a percentage. The sedimentation degree of this composition without a dispersant was 18%.

[0045] In Examples 2 to 9, various dispersants were evaluated. All the compositions of the following examples were prepared and evaluated in the same manner. The results are summarized in Table 1, which appears later in the specification.

[0046] Example 2: Composition according to the invention

[0047] The composition was prepared as described in Example 1 above. A mixture containing 49.75 wt% zeolite crystals and 49.75 wt% hydroxylated oil was prepared, and 0.5% dispersant was added thereto. To this end, 250 g of the zeolite of Example 1 was introduced into 125 g of castor oil in a plastic tank, and shear stirring was carried out at a high speed using a Rayneri mixer at a rotation speed of 1500 rpm. Then, under stirring for 30 minutes, 2.51 g of the dispersant pre-dispersed in 125 g of castor oil was added. The dispersant was an organophilic montmorillonite sold by BYK under the label AF.

[0048] About 502.5 g of a homogeneous paste was obtained. To remove the air bubbles entrained in the paste during the preparation process, the paste was heated at 60 °C, under vacuum (0.2 kPa) and gentle stirring (200 rpm) for 1 hour. A homogeneous paste with suspended and well-dispersed crystals was obtained. The sedimentation degree of the composition of Example 2 was 8.9%.

[0049] Example 3: According to the present invention

[0050] In this example, the composition was prepared as in Example 2, and the dispersant was organophilic montmorillonite sold by BYK under the label MP 250. The sedimentation degree was 8.0%.

[0051] Example 4: According to the present invention

[0052] The composition was also prepared as in Example 2, but the dispersant was replaced with organophilic sepiolite sold by BYK under the label 1958. The sedimentation degree was 6.9%.

[0053] Example 5: Comparative example:

[0054] The composition was prepared according to Example 2, using a dispersant of the modified polyalkyleneimine polyethylene glycol polyester type, sold by BYK under the label 2155. The observed sedimentation degree was 11.9%.

[0055] Example 6: Comparative example:

[0056] In the composition prepared as in Example 2, the dispersant was this time a dispersant of the acid group-functionalized copolymer type and was sold by BYK under the label 111. The sedimentation degree was 22%.

[0057] Example 7: Comparative example:

[0058] The composition was still prepared according to the scheme of Example 2. The composition of this example contained a dispersant which was a modified urea solution sold by BYK under the label DISPERBYK 7410. The sedimentation degree was 13%.

[0059] Example 8: Comparative example:

[0060] According to the scheme of Example 2, the composition of Comparative Example 8 was prepared using a dispersant of the high molecular weight polyacrylic acid type, which was sold by BYK under the label 430. The sedimentation degree was 12.1%.

[0061] Example 9: Comparative example:

[0062] In this comparative example, according to the solution of Example 2, a composition was prepared using unmodified sepiolite-type clay, sold by Tolsa under the label P400. The sedimentation degree was 17.5%.

[0063] All results are collated in Table 1 below.

[0064] --Table 1--

[0065]

[0066] The above results clearly show that organophilic layered silicate-type dispersants enable a significant reduction in the sedimentation degree of the composition of zeolite crystals dispersed in hydroxylated oil. In contrast, when the dispersant is a dispersant other than organophilic layered silicate, sedimentation becomes significant or even problematic, and may require re-homogenization before use.

Claims

1. A composition, comprising: from 30% to 70% by weight, preferably from 40% to 60% by weight, based on the total weight of the composition, of at least one hydroxylated oil, from 70% to 30% by weight, preferably from 60% to 40% by weight, based on the total weight of the composition, of crystals of at least one zeolite, and from 0.1% to 5% by weight, preferably from 0.3% to 1.5% by weight, based on the total weight of the composition, of at least one organophilic layered silicate type dispersant, It is understood that the sum of the three components of the composition as defined above reaches 100%.

2. The composition according to claim 1, wherein the hydroxylated oil is a dihydroxylated oil, a trihydroxylated oil or a polyhydroxylated oil, either alone or as a mixture of two or more thereof.

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 vegetable oils, animal oils or mineral oils, and preferably the hydroxylated oil is castor oil.

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

5. The composition according to any one of the preceding claims, wherein the at least one zeolite is selected from zeolites of the LTA type and FAU-X type, the Si / Al molar ratio of which is preferably from 1.0 to 1.5, including the end points.

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

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

8. The composition according to any one of the preceding claims, wherein the dispersant is an organophilic layered silicate selected from bentonite, palygorskite, sepiolite, attapulgite, montmorillonite, hydrotalcite, octosilicate, and preferably selected from the attapulgite group, wherein preferably sepiolite, the organophilic layered silicate being surface-functionalized with one or more compounds selected from amines, surfactants, silanes, siloxanes and alkyl chains.

9. The composition according to any one of the preceding claims, wherein the dispersant is a fibrous clay or a mixture of fibrous clays modified with one or more surfactants.

10. Use of the composition according to any one of the preceding claims for drying an organic compound, an organic composition or an organic solution.

11. The use according to the preceding claim, wherein the use is for drying an organic composition for the preparation of a 2K resin.

12. The use according to the preceding claim, wherein the use is for drying an organic composition for the preparation of a polyurethane resin.

13. The use according to the preceding claim, wherein the use is for drying the polyol for preparing polyurethane resin.

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