JPH02293315A - Clay mineral complex and production thereof - Google Patents

Abstract

PURPOSE:To obtain a clay mineral complex having an intercalant held between layers by swelling a specific clay mineral in a solution containing the intercalant dissolved therein the then adding a poor solvent for the intercalant thereto. CONSTITUTION:A solution containing an intercalant dissolved in a good solvent therefor is prepared. A clay mineral having quaternary ammonium ions or substituted phosphonium ions exchanged and bonded between layers is prepared. The clay mineral is swelled in the above-mentioned solution and a poor solvent for the aforementioned intercalant is then added to hold the intercalant between the layers of the above-mentioned clay mineral. Thereby, a clay mineral complex in which organic cations are subjected to ion exchange and binding between the layers of the clay mineral and the intercalant is simultaneously held is obtained. The aforementioned intercalant is selected from coloring matters, agricultural chemicals, fertilizers, medicines, perfumes, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a clay mineral composite, and in particular to a pigment. ! 4 drugs.
This article relates to a clay mineral composite in which intercalants selected from a wide range of substances such as fertilizers, pharmaceuticals, and fragrances are retained between layers, and a method for producing the same. [Summary of the Invention] The present invention provides a clay mineral composite in which an intercalant is bonded between layers of clay minerals, in which various functions are further provided between the layers of clay minerals in which organic cations have been bonded by ion exchange between the layers. By retaining the intercalant and creating a clay mineral complex, it is possible to stably maintain and develop the function of the intercalant. The present invention further provides a method in which a clay mineral in which quaternary ammonium ions or substituted phosphonium ions are ion-exchange bonded between layers is swollen in a solution in which an intercalant is dissolved in a good solvent thereof, and then a poor solvent for the intercalant is added. By doing so, it is possible to easily produce a clay mineral composite as described above.

(Conventional technology) Microcapsules have traditionally been used as an excellent technology to solidify liquids and handle them, to keep specific substances isolated from the external environment except when necessary, and to control sustained release. Microencapsulation is a technology that encapsulates minute particles or droplets in polymer membranes, lipid membranes, etc.Currently, its most important application is carbonless paper. Paper is colored by releasing leuco dyes such as crystal violet lactone encapsulated in microcapsules by breaking the capsule wall using external pressure, and opening the lactone ring of the leuco dye by contacting with external solid acid. In other words, by encapsulating the leuco dye in microcapsules, contact between the leuco dye and the solid acid during non-recording is cut off. and essential oil fragrance,
Reducing surface toxicity and controlling sustained release of pesticides and herbicides,
It is used to control the sustained release of pharmaceuticals. [Problem to be solved by the invention] As mentioned above, microencapsulation is a useful technology,
Various encapsulation methods have been developed depending on the nature of the substance (core substance) to be encapsulated. However, techniques such as coacel-based interfacial polymerization, which are performed particularly when a hydrophobic organic compound is used as the core material, are generally complicated. In addition, in microcapsules, the core substance is isolated from the external environment by the capsule wall, and therefore the core substance cannot be brought into reversible contact with or out of contact with the external environment by chemical processes.

Therefore, an object of the present invention is to provide a material that can stably hold a specific substance in a state where it can come into contact with the external environment, which has properties that cannot be achieved by microencapsulation.

A further object of the present invention is to provide a technique for producing such materials through easy operations.

[Means for Solving the Problems] In the process of investigating surface treatment techniques for clay-based intercalation compounds, the present inventors previously retained organic cations between the layers of clay minerals to expand the interlayer distance, and The inventors discovered that the desired effect can be obtained by retaining an intercalant between the layers, leading to the completion of the present invention. That is, the clay mineral composite according to the first aspect of the present invention is characterized in that organic cations are bonded by ion exchange between clay mineral layers and intercalants are retained.

Furthermore, the method for producing a clay mineral composite according to the second aspect of the present invention includes a solution in which a clay mineral in which quaternary ammonium ions or substituted phosphonium ions are ion-exchange bonded between the layers and an intercalant dissolved in a good solvent thereof. After swelling in the clay mineral, a poor solvent for the intercalant is added to hold the intercalant between the layers of the clay mineral.

First, clay minerals used in the present invention include those having a layered structure and having exchangeable cations between the layers. A typical example is montmorillonite group minerals.

Montmorinite group minerals have the following general formula (X, Y)z-
sZ40+o(OH)z. mHzo・(W+z:+) [
However, X=Al, Fe(I[l). Mn(I
II), Cr(I[[), Y=Mg. Fe(II)
．． Mn ((1), Ni.Zn, Li, Z=Si
,A/! , W=K, Na, Ca, and H. O represents interlayer water and m represents an integer. ] It is a clay mineral with a three-layer structure. Depending on the combination of X and Y and the number of substitutions, montmorillonite and magnesian montmorillonite are produced. Iron montmorillonite. Ferromagnesian montmorillonite beidellite Aluminum ambaidellite. Nontronite, aluminian nontronite, saponite, aluminian saponite. Hectorite. There are many types such as sauconite, but in addition to these natural products, synthetic products in which the OH group in the above formula is substituted with fluorine are also available.

In addition to the above-mentioned montmorite group minerals, mica group minerals such as sodium silicinmaite, sodium taeniolite, pentalithium taeniolite, etc. can be used. Kaolinite and talc have a layered structure but do not have exchangeable cations between the layers. Pyrophyllite etc. are unsuitable. Also,
Zeolite has alkali metal ions or alkaline earth metal ions as exchangeable cations, but its structure is network-like and the pore size is small, so its practical performance is somewhat inferior.

These clay minerals are used with organic cations bonded by ion exchange between their layers. Preferred organic cations include quaternary ammonium ions and alkylphosphonium ions. and an arylphosphonium ion. These organic cations play the role of expanding the distance between the layers of clay minerals, and using their hydrophobic chains, change the originally hydrophilic layers of clay minerals to become hydrophobic, making it easier to retain various organic compounds. It is something.

By the way, in the field of pigments and reversible coloring and fading materials, clay composites in which a quaternary ammonium ion structure is introduced between layers of clay minerals have been known for some time. For example, Japanese Patent Publication No. 50-8462 discloses a coloring method in which a basic dye having a structure such as a quaternary ammonium salt is retained by ion exchange with exchangeable cations existing between crystal layers of zeolite and/or montmorillonite. A composite pigment is disclosed. Also, JP-A-57-3
Japanese Patent Application No. 5753 discloses a coloring material with decoloring properties, in which a phthalein indicator into which a dialkylaminomethyl group has been introduced is cationized with an acid (quaternary ammonium ionization) and then adsorbed onto clay minerals. Furthermore, JP-A-63
- Publication No. 90573 discloses a lipophilic colored composite pigment composition in which a hydrophobic colored complex formed by a quaternary ammonium salt type cationic activator and an acidic dye is adsorbed on a water-swellable clay mineral such as montmorillonite. ing. Furthermore, Japanese Patent Application Laid-Open No. 62-256724 discloses that quaternary ammonium salt type compounds are talc, mica, etc. A conductive inorganic powder that is adsorbed onto an inorganic powder such as clay and used as an antistatic agent has been disclosed. These conventional techniques differ in whether a quaternary ammonium ion structure is introduced as part of the molecular structure of the intercalant, or whether the intercalant and the quaternary ammonium ion form a complex, but none of them The dye and the quaternary ammonium ion behave as one. On the other hand, in the present invention, since the clay mineral preliminarily holds organic cations such as quaternary ammonium ions between layers, the intercalant does not necessarily have to have a quaternary ammonium type structure.
Moreover, only the intercalant can move in and out between the layers of clay minerals by itself. Therefore, it is extremely different in character from the conventional technology. For this reason, in the present invention, the fourth
Intercalants are not limited to acidic compounds as they are when forming complexes with ammonium ions. Organic cations used in the present invention include quaternary ammonium ions or substituted phosphonium ions. Here, the substituted phosphonium ion is
Refers to alkylphosphonium ions and arylphosphonium ions. The number of carbon atoms in the hydrocarbon group contained in these organic cations is not particularly limited, but it is preferable to select one so that the resulting organic cation is easily soluble in a good solvent for the intercalant. The quantitative range of existing cations bonded by ion exchange between the layers of the clay mineral is not particularly limited, and the E limit is the exchangeable capacity, and the lower limit is the interlayer distance that is larger than the diameter of the dye molecule. You can set it appropriately considering the required amount. The intercalant used in the present invention is a substance that can be incorporated between the layers of clay minerals modified with organic cations as described above (hereinafter referred to as modified clay minerals).
It is not particularly limited, and can be selected from a wide range of pigments, pesticides, fragrances, etc. Therefore, the obtained clay mineral composite also exhibits various functions, but a particularly important application is thought to be a recording material using a dye as an intercalant, which will be explained in detail below.

The dyes used in the present invention are selected from those that develop, decolor, or change color through redox reactions, such as triphenylmethane phthalides. Fluorans, thiofluoranes, indolylphthalides, rhodamine lactams. Leuco dyes having a lactone ring such as azaphthalides are representative.

First, examples of triphenylmethane phthalides include crystal violet lactone and malachite green lactone, and examples of fluorans include 3-diethylamino-6-methyl-7-chlorofluoran and 3-diethylamino-7-methoxyfluoran. 3-diethylamino-6-benzyloxyfluorane 1 2-henzu-6-diethylaminofluorane, 3.6-diP-}luidino 4 5-dimethylfluoran-phenylhydrazide T-lactam, 3-amino-5-methylfluoran Oran. 2-Methyl-3-amino-6-methyl-7-methylfluorane. 2.3-Butylene-6-di-n-butylaminofluorane. 3-diethylamino-7-ayurinofluorane, 3-diethylamino-7-valatoluidinofluorane. 7-acetamino-3-diethylaminofluorane. 2-promo 6-cyclohexylaminofluorane. Examples include 2,7-dichloro-3-methyl-6-n-butylaminofluoran. Further, as the thiofluorane, 3-jethylamino 6-methyl-7-dimethylaminothiofluoran. 3-diethylamino-7
-dibenzylaminothiofluorane, etc., and indolyl phthalides include 8-(4-diethylaminophenyl)8-(1-ethyl-2-methylindole-8
yl) phthalide, 3.3-bis(1-ethyl 2-methyl-8-yl) phthalide. 3.3-Bis(2-phenylindole-3-yl)phthalide 3-(4-di-n-butylaminophenyl)-3(2-phenylindole-3
Examples of rhodamine lactams include rhodamine lactone, , azaphthalides include 3,3-bis(1-ethyl-2-methylindol-3-yl)-7-azaphthalide, etc.Other examples include leucobasic fuchcyanin, leucomalachite green, leuco crystal violet, p, p'
- Tetradimethyldiaminobenzophenone (Michler's Ketone), oxazine-based leuco thermosensitive dyes (manufactured by Hodogaya Chemical Co., Ltd., trade name: CSB-12, etc.), spiropyran-based leuco thermosensitive dyes (manufactured by Hodogaya Chemical Co., Ltd., trade name: CSR-13, etc.),
Quinoline-based leuco heat dyes (manufactured by Hodogaya Chemical Co., Ltd., trade name CSY-113, etc.), as well as redox indicators, PH indicators, viologens. Electron donors such as tetrathiofulvalene (TTF), electron acceptors such as tetracyanoquinodimethane (TCNQ), Prussian blue iridium monooxide formed by electrolytic synthesis, and polyvirol formed by electrolytic polymerization. It is also possible to use polythiophene, polyaniline, or derivatives thereof, rare earth cyanine produced by a vacuum smoked method, tungsten dioxide, and the like.

The above-mentioned leuco dyes may be used alone or in combination of two or more to control color tone and the like. The amount of leuco dye added is not particularly limited, but the upper limit is selected to maximize the interlayer distance of the modified clay mineral. If more than this is added, the interlayers of the modified clay mineral will be saturated and the leuco dye will not be intercalated.

In order to make the modified clay mineral retain various intercalants in the present invention, the modified clay mineral is first dispersed in a solvent in which the intercalant is dissolved and swelled. The solvent at this time must be a good solvent for the intercalant. Next, a poor solvent for the intercalant is added to the dispersion to transfer the intercalant between the layers of the modified clay mineral. The amount of the poor solvent added at this time is sufficient to significantly bias the distribution of the intercalant between the layers of the modified clay mineral and the liquid phase toward the interlayer side.

[Effect]

As shown in Fig. 1, Montmorinite, which is a typical clay mineral used in the present invention, is composed of a repeating three-layer structure (1) with a regular octahedron as its basic skeleton. In the interlayer (2) of (1), n molecules of interlayer water and alkali metal ions, which are exchangeable cations, are held.

The distance between the layers (2) increases or decreases depending on the ion diameter of the intercalant.

FIG. 2 schematically shows the structure of montmorichonite and shows how the intercalant is incorporated between layers of a modified clay mineral in which exchangeable cations are ion-exchanged with quaternary ammonium ions.

First, untreated Montmori Kuchinite (10) is [state A]
As shown in the figure, sodium ions (12) are present as exchangeable cations between the layers (11). Let the interlayer distance at this time be d1.

When the above-mentioned Montmori Kuchinite (10) is swollen with water and quaternary ammonium ions (13) are added, ion exchange occurs as shown in [state B], and the quaternary ammonium ions replace the above-mentioned sodium ions (12). ion (13)
is taken into the interlayer (11). This state is a modified clay mineral (1). The interlayer distance Mat of the modified clay mineral (1) is larger than the interlayer distance d of the bird-treated montmorinite (10). The above-mentioned modified clay mineral (1) is isolated and redispersed in a solvent in which the intercalant (14) is dissolved, as shown in [State C]. The solvent used here is selected to be a good solvent for the intercalant (l4), and considering that the intercalant (l4) is often an organic compound, a general-purpose organic solvent is used. . This modified clay mineral (1) retains a quaternary ammonium ion (13) having a hydrophobic chain between layers (l1), so it swells in the above-mentioned general-purpose organic solvent. At this time,
A part of the intercalant (14) may be incorporated into the interlayers of the modified clay mineral, but at this stage the distribution is still largely biased toward the liquid phase, and most of the intercalant (14) is Exists in a free state.

However, if a large amount of water, for example, is added as a poor solvent for the intercalant (14) to the system in [state C], the solubility of the intercalant (14) in the liquid phase decreases and the interlayer ( 11), and as a result, as shown in [state D], the intercalant (14) migrates to the interlayer (11) of the modified clay mineral (1). This state is a clay mineral complex (I
I). The interlayer distance d of the clay mineral complex (II),
is further expanded than the interlayer distance d2 of the modified clay FL product (1). Since the clay mineral composite (II) uses clay mineral as a carrier, it can be handled as a powder after drying.

In the above clay mineral complex (mouth), as is clear from Figure 2, although the intercalant is supported by the clay mineral, it is isolated from the external environment as in the case of being encapsulated in microcapsules. isn't it. therefore,
It is possible for intercalants to move in and out in response to changes in the external environment, and for example, when leuco dyes are intercalated, it is also possible to cause reversible color development, fading, or color change. Moreover, the above clay mineral complex (II
) can be easily produced by extremely simple operations such as dispersion and stirring in a solution [Example] Hereinafter, preferred examples of the present invention will be described based on experimental results.

Experimental Example: As a preliminary experiment, modified clay minerals were prepared using montmorichonite and three types of quaternary ammonium ions, and the interlayer distance and solvent swelling properties were investigated. First, 10 g of Montmori Kuchinite was allowed to swell in 900 ml of ion-exchanged water (hereinafter simply referred to as water) for 1 minute, and 2.80 g of n-decyltrimethylammonium bromide (DeTAB) dissolved in 100 mj2 of water was added. (
When 10 mg (equivalent) was added, the powder immediately agglomerated and precipitated. After this dispersion was allowed to stand overnight while being further stirred, the precipitate was filtered off and washed with a large amount of water to remove unreacted quaternary ammonium salt. This precipitate was dried under reduced pressure at 70'C to obtain an off-white powder (modified clay mineral). A similar operation was carried out with di-n-decyldimethylammonium bromide (DDeDAB) and tetra-n-bromide.
-decylammonium (TeDeAB) to obtain the corresponding modified clay tfL products.

However, when adding di-n-decyldimethylammonium bromide, add it as a stock solution, and when using tetra-n-decyl ammonium bromide, to compensate for the solubility, 100 mN of water/ethanol (1:l) mixed solvent is used. It was added after being dissolved in the liquid.

Regarding the modified clay mineral thus obtained, the (001) plane spacing, that is, the interlayer distance was measured by X-ray diffraction. The results are shown in Table 1. Note that in the interlayer distance column, the numbers in brackets indicate the amount of increase based on the interlayer distance of 9.78 people for untreated Montmori Kuchinite.

(Margins below) Table 1 and Figure 3 show modified clay minerals (
Hereinafter, it will be referred to as DeTAB-treated clay mineral. The same applies when using other quaternary ammonium salts. ) is shown. Here, the peak at 2θ=6.3@ has an interlayer distance of 14.
It accommodates 02 people.

From these results, for any modified clay mineral,
It was found that the interlayer distance increased compared to the untreated montmori stomite. The degree of increase is greater as the quaternary ammonium ion has more long alkyl chains (n-decyl groups) in its side chains. Next, ethanol of these modified clay minerals. acetone,
Solvent swelling properties in toluene were investigated. That is, 1 part by weight of the modified clay mineral was added to 60 parts by weight of the above solvent, ultrasonic dispersion was performed for 10 minutes, the resulting dispersion was applied to a glass sample plate, and X-ray diffraction was performed in a wet state. The interlayer distance was measured. The results are shown in Table 2. In the column of interlayer distance, the numbers in brackets indicate the amount of increase based on the interlayer distance of the modified clay mineral in the dry state shown in Table 1 above.

Table 2 From the results, it is clear that the solvent swelling properties vary depending on the species frequency of quaternary ammonium ions between the layers.

Experimental Example 2 Here, an experiment was conducted in which a leuco dye was further incorporated as an intercalant between the layers of the modified clay mineral. As the leuco dye, a black-coloring fluoran dye (manufactured by Hodogaya Chemical Co., Ltd., trade name CF51) was used. Since this leuco pigment has a solubility in acetone of /8 (solubility at 20'C is 50 g per liter of acetone), as a modified clay mineral, DeTAB treatment, which has a high solvent swelling property with acetone, should be used as a modified clay mineral. I chose clay minerals.

In addition, water (solubility at 20"C is 0.34 mg per liter of water) was used as a poor solvent when incorporating the leuco dye between the layers of the clay mineral. First, 1 part by weight of the leuco dye (CF51) was added to acetone. 10
0 parts by weight, 3 parts by weight of DeTAB-treated clay minerals were added to this solution, and ultrasonic dispersion treatment was performed for 10 minutes.
A cloudy dispersion was obtained. 100 parts by weight of water, which is a poor solvent for the leuco dye, was added to this dispersion while stirring.
At this stage, no powder agglomeration or precipitation occurred. However, when 2000 parts by weight of water was added all at once, the powder coagulated and precipitated. When the precipitate was filtered and dried under reduced pressure at 50°C, a slightly reddish-purple powder was obtained.
This powder developed a deep black color when treated with hydrochloric acid, but the filtrate showed almost no color even when the pH was adjusted to 1. This suggested that the leuco dye was incorporated between the layers of the DeTAB-treated clay mineral and was almost absent in the liquid phase.

In addition, the fact that the above-mentioned powder changed color sharply upon contact with hydrochloric acid means that the leuco pigment is held between the layers of clay minerals but is placed in a state where it can come into contact with the external environment. For example, this is very different from when it is encapsulated in microcapsules. Next, the reddish-purple powder was subjected to X-ray diffraction. The results are shown in Figure 4. In the figure, the presence of peaks at 2θ = 1.26° (corresponding to an interlayer distance of 70.06 people) and 2θ = 2.67° (corresponding to an interlayer distance of 33.06 people) indicates that the above powder is decyltrimethylammonium. As a result of incorporating leuco dye in addition to ions, the DeT shown in Figure 3 above
It can be seen that the interlayer distance increased by about 19 to 56 people compared to the AB treated clay mineral. Experimental Example 3 In place of water in Experimental Example 2, n-hexane (20°C
The solubility in n-hexane is 300 mg per liter)
A clay mineral composite was prepared in the same manner using as a poor solvent.

The X-ray diffraction spectrum of the obtained powder is shown in FIG. In the figure, the presence of peaks at 2θ-1.36° (corresponding to interlayer distance of 64.91 people) and 2θ = 3.50' (corresponding to interlayer distance of 25.22 people) indicates that this powder was Similar to example 2,
It was confirmed that it is a clay mineral complex with expanded interlayer distance. The coloring behavior due to acid was also similar. Experimental Example 4 In this experiment, we investigated the correlation between the amount of intercalant incorporation and the increase in interlayer distance. The above-mentioned CF51 was used as the leuco dye, DDeDAB-treated clay mineral was used as the modified clay mineral, and water was used as the poor solvent. First, a predetermined amount of leuco dye (C
7 parts by weight of DDeDAB-treated clay minerals were added to a solution in which F51) was dissolved, and while stirring this dispersion using a magnetic stirrer, 800 parts by weight of water from Viellet was added at 0.5 m/7.
! It was dropped at a rate of . After completion of the dropwise addition, the dispersion was allowed to stand, and the formed precipitate was filtered off, washed with a large amount of water, and then dried under reduced pressure at 60°C.

Here, the amount of leuco dye used is O. In each case, the interlayer distance of the obtained clay mineral composite was measured by X-ray diffraction.

FIG. 6 shows the results of plotting the interlayer distance against the amount of leuco dye incorporated. In the figure, the vertical axis represents the interlayer distance (input), and the horizontal axis represents the amount (g) of leuco dye taken in per gram of DDeDAB-treated clay mineral. However, in this experimental system, as is clear from Experimental Example 2, almost the entire amount of the leuco dye added to the dispersion is incorporated between the layers, so it can be considered that the amount of leuco dye used and the amount incorporated are approximately equal.

The results of this experiment supported the behavior in which the interlayer distance increases in response to the incorporation of leuco dyes.

[Effects of the Invention] As is clear from the above explanation, if the clay mineral composite according to the present invention is used, specific substances can be stably retained and powdered without using techniques such as encapsulation in microcapsules. In addition, when necessary, it can be quickly activated by changing the external environment. In particular, when a leuco dye is used as an intercalant, it may be possible to provide a new display material.

In addition, in the above method for producing a clay mineral composite, a poor solvent is added to incorporate the intercalant between the layers of the clay mineral, so the efficiency of incorporation is extremely high, and the operation is simpler than in the production of microcapsules. It is easy to use. Therefore, it becomes possible to provide a clay mineral composite with high productivity and economic efficiency.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the crystal structure of montmori kuchinite. Figure 2 is a schematic diagram to explain the principle of interaction. Figure 3 is a chi-ray diffraction spectrum diagram of the DeTAB-treated clay mineral, and Figure 4 is an X-ray diffraction spectrum diagram of a clay mineral composite in which a leuco dye is incorporated between the layers of the DeTAB-treated clay mineral. Figure 5 is an X-ray diffraction spectrum of a clay mineral composite prepared by another method. Figure 6 is a characteristic diagram showing the relationship between the interlayer distance and the amount of leuco dye incorporated into the DDeDAB-treated clay fabric. l4 ■ Montmorite intercalated sodium ion quaternary ammonium ion modified clay mineral intercalant clay mineral complex

Claims (2)

[Claims] (1) A clay mineral complex in which organic cations are bonded by ion exchange between layers of clay minerals and intercalants are retained. (2) Swelling a clay mineral in which quaternary ammonium ions or substituted phosphonium ions are bonded by ion exchange between layers in a solution of an intercalant dissolved in a good solvent thereof, and then adding a poor solvent for the intercalant. A method for producing a clay mineral composite, characterized in that an intercalant is retained between the layers of the clay mineral.