KR101315405B1 - Process for preparing hydrophobic inorganic oxide by using microwave - Google Patents

Abstract

The present invention relates to a method for producing an organicized inorganic oxide having controlled surface properties, in particular, a method for producing an inorganic oxide having excellent hydrophobicity by uniformly bonding a silane coupling agent to the surface of the inorganic oxide by providing a constant energy using microwaves. It is about.

Description

Method for producing hydrophobic inorganic oxide using microwave {PROCESS FOR PREPARING HYDROPHOBIC INORGANIC OXIDE BY USING MICROWAVE}

The present invention relates to a method for modifying the surface of the inorganic oxide particles to hydrophobic, and more particularly to coating the surface of the inorganic oxide with a silane coupling agent having a hydrophobic functional group and chemically modified using microwaves to provide excellent rubber mixtures and resins. It relates to a method for producing a hydrophobic inorganic oxide having a dispersibility.

Inorganic oxides such as titania and mica are used as fillers for organic composites in various applications such as tires, films, and latexes.

It is necessary to control the surface characteristics of the inorganic oxide according to the surface characteristics of the organic composite and the particles. In order to have even dispersibility in the organic composite because the particles of the general inorganic oxide exhibit hydrophilicity, the characteristics of the surface of the inorganic oxide are controlled. I need to do it.

One of these methods is a method of modifying the surface of an inorganic oxide with a silane coupling agent. Conventional methods for modifying inorganic oxides are known in which a method of modifying a surface by adding an inorganic oxide to a large amount of a solution and controlling pH or stirring for a long time in a reflux state. However, in the case of performing the surface modification by the solution reaction as described above, it takes a relatively long time to complete the reaction, and furthermore, the gelation phenomenon occurs due to the evaporation of the solvent over time, there is a difficulty in the smooth reaction.

In addition, recently, as another method of modifying the inorganic oxide, a method of modifying the surface by coating the surface of the inorganic oxide with a silane coupling agent and heat treatment at high temperature or high temperature and high pressure for a long time is known. However, in the case of such a heat treatment process, a heat treatment process is required above a predetermined temperature required for the reaction, and the reaction time becomes longer as the heat transfer time is required from the outside, which leads to an increase in the overall manufacturing time. .

Therefore, research is needed to develop a process for producing a hydrophobic inorganic oxide which is more effective and stable in modifying the surface by using a silane coupling agent to improve the dispersibility of the inorganic oxide as a filler in organic composites of various uses.

The present invention is to provide a method for producing a hydrophobic inorganic oxide that can significantly shorten the process time by using a microwave when modifying the surface of the inorganic particles with a silane coupling agent.

The present invention provides a method for producing a hydrophobic inorganic oxide comprising a) coating an inorganic oxide surface with a silane coupling agent, and b) irradiating microwaves at 100 to 1,200 MHz to the coated inorganic oxide.

Hereinafter, a method of preparing a hydrophobic inorganic oxide and a hydrophobic inorganic oxide prepared according to a specific embodiment of the present invention will be described in detail. It will be apparent to those skilled in the art, however, that this is not intended to limit the scope of the invention, which is set forth as an example of the invention, and that various modifications may be made to the embodiments within the scope of the invention.

&Quot; Including "or" containing ", unless the context clearly dictates otherwise throughout the specification, refers to any element (or component) including without limitation, excluding the addition of another component .

According to one embodiment of the invention, a method for producing a hydrophobic inorganic oxide comprising a) coating an inorganic oxide surface with a silane coupling agent, and b) irradiating the coated inorganic oxide with microwave at 100 to 1,200 MHz. This may be provided.

The present inventors have found that the inorganic oxide coated with a silane coupling agent having a hydrophobic functional group can be chemically modified by using a microwave in a specific frequency range, thereby making it possible to more effectively prepare an organic hydrophobic inorganic oxide having high dispersibility in a rubber mixture. This invention was completed. According to the present invention, the manufacturing time of the hydrophobic inorganic oxide is greatly shortened, and the hydrophobic inorganic oxide having high dispersibility can be prepared compared to the existing method.

In particular, microwaves represent electromagnetic waves with a frequency of about 1 to 1000 Hz and wavelengths of 1 mm to 1 m and transmit energy through dipole rotation or ionic conduction of materials. Accordingly, the polar material selectively transmits a lot of energy, and the nonpolar material has a small energy transfer, thereby rapidly localizing the polar material. The characteristics of these microwaves are expected to increase the efficiency of surface modification by effectively transferring heat to polar OH groups present on the surface of the inorganic oxide.

As described above, the present invention is a hydrophobic inorganic oxide manufacturing method can be represented by the following two steps, a) coating the surface of the inorganic oxide with a silane coupling agent, and b) 100 to 1,200 MHz to the coated inorganic oxide Irradiating the microwaves.

First, coating the inorganic oxide surface with a silane coupling agent. In this case, the coating step may be performed by an impregnation method, a spray method, or a ball mill method. In particular, in the method of coating inorganic particles with a silane coupling agent, an impregnation method of mixing the silane coupling agent with an inorganic oxide together with an organic solvent to remove the organic solvent after mixing and spraying a silane coupling agent onto the surface of the inorganic oxide There is a method of mixing after direct injection through. The organic solvent used in the impregnation method is a solvent capable of mixing both inorganic particles and silane coupling agents as well as dimethylchloride, methanol, methanol, ethanol, propanol and ethyl acetate. One or more organic solvents such as diethyl ether may be used, but the solvent may be changed by the properties of the inorganic particles and the silane coupling agent, and the solvent is not limited thereto. In the coating method of the inorganic oxide, the mixing time is suitable for about 10 minutes to 6 hours, which can be appropriately adjusted according to the amount of hydrophobic inorganic particles or the content of the silane coupling agent.

In the present invention, the inorganic particles coated with the silane coupling agent, that is, the inorganic oxide may use at least one of titania, pearl, mica, clay, and the like having an OH group on its surface.

In addition, the silane coupling agent coated on the surface of the inorganic oxide is a silane coupling agent represented by the following formula (1) having hydrophobicity.

[Formula 1]

Wherein,

R ¹ , R ² , and R ³ are the same as or different from each other, and each is an alkyl group having 1 to 5 carbon atoms, preferably a methyl group, an ethyl group, or a propyl group;

R ⁴ is a linear or branched alkyl group having 1 to 18 carbon atoms, preferably a propyl group, an octyl group, a decyl group, a dodecyl group, or an octadecyl ( octadecyl) group.

The silane coupling agent may include at least one selected from the group consisting of propyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, and octadecyltrimethoxysilane. have.

The content of the silane coupling agent in the coating step may be 0.1 to 30 parts by weight, preferably 1 to 20 parts by weight based on the weight of the inorganic oxide. The content of the silane coupling agent may be used in an amount of 0.1 parts by weight or more based on the weight of the inorganic oxide in terms of hydrophobicity control, and may be used in an amount of 30 parts by weight or less based on the weight of the inorganic oxide in terms of economy.

In addition, the inorganic oxide coated with the silane coating agent having the hydrophobic functional group may be prepared as a hydrophobic inorganic oxide having an inorganic oxide surface modified through a process of irradiating microwaves at a specific frequency. At this time, the microwave is applied at a frequency of 100 to 1,200 MHz, preferably can be irradiated with a microwave of 300 to 1000 MHz. If the frequency of the microwave is less than 100 MHz, the total reaction time is long, and if it exceeds 1,200 MHz, since the temperature of the reactant is rapidly increased, it gives a uniform and effective hydrophobicity to the surface of the inorganic oxide. It is difficult to control.

In the present invention, the irradiation intensity and time of the microwave can be changed depending on the total reactant content, the irradiation time is appropriately adjusted from 1 minute to 30 minutes. When the irradiation time of the microwave is less than 1 minute, it may be difficult to realize the desired performance because the reactants are not chemically modified properly, and when irradiated for more than 30 minutes, the temperature rise of the reactants becomes very large and thus the Problems with shape deformation and safety of the device may occur.

As described above, the present invention is characterized in that a hydrophobic inorganic oxide having high dispersibility which can be used as a tire filler is produced by using a microwave of a specific frequency. In other words, when surface modification of inorganic oxide powder with silane coupling agent, after surface coating inorganic oxide with silane coupling agent, the surface is directly modified by using microwave, unlike the method of modifying the surface by transferring energy through heat transfer. In this way, the manufacturing time of the existing hydrophobic inorganic oxide may be shortened.

On the other hand, the present invention provides a hydrophobic inorganic oxide prepared by coating the surface of the inorganic oxide with a silane coupling agent in the same manner as described above and irradiated with microwaves.

The present invention also provides a rubber mixture or resin composition comprising the hydrophobic inorganic oxide thus prepared, and a tire, film, latex and the like comprising the same.

In the present invention, matters other than those described above can be added or subtracted as required, and therefore, the present invention is not particularly limited thereto.

According to the present invention, the microwaves having a specific frequency can be irradiated to directly transmit an optimized range of energy, thereby hydrophobicizing the surface of the inorganic oxide having hydrophilicity, thereby improving dispersibility in the organic composite.

According to the present invention, by establishing an optimized energy transfer process using a specific range of microwaves, it is possible to shorten the time compared to the method of chemically modifying the inorganic oxide and silane coupling agent by the conventional heat treatment method, which is an inorganic oxide There is an advantage that can shorten the overall process time used to modify the surface of the, has the advantage of effectively obtaining a hydrophobic inorganic oxide.

1 is a photograph showing the results of separation experiments with water of hydrophobic mica prepared according to Examples 1 to 3 of the present invention.
Figure 2 is a photograph showing the results of separation experiments with water of hydrophobic mica prepared according to Comparative Examples 1 and 2 of the present invention.
3 is a weight loss rate according to temperature (° C.) change of temperature (℃) for mica that has not been subjected to a separate surface modification process, surface modified mica according to Example 1, and surface modified mica according to Comparative Example 1; ,%).

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited to the following examples.

Example  One

10 g of mica was mixed with 100 mL of an organic solvent, dimethyl chloride, and 0.5 g of a silane coupling agent, propyltriethoxysilane (PTES), and stirred at room temperature for 30 minutes, followed by evaporation. Dimethyl chloride was removed to coat a silane coupling agent having a hydrophobic functional group on the pearl surface. The coated mica was irradiated for 10 minutes using a microwave of 700 MHz to prepare a hydrophobic pearl surface modified.

In order to evaluate the hydrophilicity / hydrophobicity of the prepared hydrophobic mica, 1 g of modified mica was added to a vial, followed by sonication for 10 minutes after mixing with water, and confirming the separation performance with water. 1 is shown.

As a result of evaluating the separation performance with water, it was confirmed that after the reforming, the mica became completely hydrophobic and floated in water 100%.

Example  2

A mica having hydrophobicity was prepared in the same manner as in Example 1, except that 0.1 g of decyltrimethoxysilane (DTMS) was used as the silane coupling agent and irradiated for 15 minutes using a microwave at 700 MHz. .

About the prepared hydrophobic mica was confirmed the separation performance with water in the same manner as in Example 1 and the measurement result photograph is shown in FIG. As a result of the separation performance evaluation with water, it was confirmed that after modification, the mica became completely hydrophobic and floated in water 100%.

Example  3

A hydrophobic mica was prepared in the same manner as in Example 1, except that 1 g of decyltrimethoxylsilane (DTMS, decyltrimethoxysilane) was used as the silane coupling agent and irradiated for 15 minutes using a microwave at 700 MHz.

About the prepared hydrophobic mica was confirmed the separation performance with water in the same manner as in Example 1 and the measurement result photograph is shown in FIG. As a result of the separation performance evaluation with water, it was confirmed that after modification, the mica became completely hydrophobic and floated in water 100%.

Example  4

In the same manner as in Example 1, except that 10 g of pearl as the inorganic oxide and 0.1 g of decyltrimethoxysilane (DTMS) as the silane coupling agent were irradiated for 15 minutes using 700 MHz microwave. Hydrophobic pearls were prepared.

Separation performance with water was confirmed in the same manner as in Example 1 for the prepared hydrophobic pearl. As a result of evaluating the separation performance with water, it was confirmed that after modification, the silica became completely hydrophobic and floated 100% in water.

Process conditions for the method for preparing hydrophobic silica according to Examples 1 to 4 and water and separation performance evaluation of the prepared hydrophobic silica are shown in Table 1 below.

division microwave
Intensity (MHz) microwave
Irradiation time (min) weapon
oxide Silane coupling agent
(content) Water and separation performance Example 1 700 10 Mica PTMS (5 wt%) Complete separation Example 2 700 15 Mica DTMS (5 wt%) Complete separation Example 3 700 15 Mica DTMS (10 wt%) Complete separation Example 4 700 15 pearl DTMS (10 wt%) Complete separation

As shown in Table 1 and Figure 1, it can be seen that the hydrophobic inorganic oxides of Examples 1 to 4 prepared using microwaves of the optimized frequency according to the present invention have been given hydrophobicity to a very good degree.

Comparative Example  One

10 g of mica was mixed with 100 mL of an organic solvent, dimethyl chloride, and 1 g of propyltrimetholoxysilane (PTMS, propyltrimethoxysilane) as a silane coupling agent, and stirred at room temperature for 30 minutes, followed by a distillation apparatus ( Dimethyl chloride was removed through evaporation to coat a silane coupling agent with a hydrophobic functional group on the surface of the mica. The coated mica was heat treated in a heating furnace at 120 ° C. for 15 minutes to prepare a hydrophobic mica.

About the prepared hydrophobic mica was confirmed the separation performance with water in the same manner as in Example 1 and the measurement result photograph is shown in FIG. As a result of the separation performance evaluation with water, the prepared hydrophobic mica was found to be completely mixed with water.

Comparative Example  2

A hydrophobic mica was prepared in the same manner as in Comparative Example 1, except that DTMS was used as a silane coupling agent at 5 parts by weight, and the coated mica was heat-treated in a heating furnace at 120 ° C. for 30 minutes.

The prepared hydrophobic silica was confirmed to have a separation performance from water in the same manner as in Comparative Example 1, and the measurement result photograph is shown in FIG. 2. As a result of the separation performance evaluation with water, the prepared hydrophobic mica was found to be completely mixed with water.

Comparative Example  3

Hydrophobic pearls were prepared in the same manner as in Comparative Example 1, except that inorganic oxides were used as pearls, 10 parts by weight of the silane coupling agent was used, and the coated pearls were heat-treated in a heating furnace at 120 ° C. for 1 hour. .

Separation performance with water was confirmed in the same manner as in Comparative Example 1 with respect to the prepared hydrophobic pearl. As a result of the separation performance evaluation with water, the prepared hydrophobic silica was confirmed to be completely mixed with water.

Process conditions and water and separation performance evaluation of the prepared hydrophobic silica according to Comparative Examples 1 to 3 are shown in Table 2 below.

division Inorganic oxide Heat treatment temperature
(℃) Heat treatment time
(min) Silane coupling agent
(content) Water and separation performance Comparative Example 1 Mica 120 30 PTMS (10 wt%) Not separated Comparative Example 2 Mica 120 60 DTMS (5 wt%) Not separated Comparative Example 3 pearl 120 60 DTMS (10 wt%) Not separated

As shown in Table 2 and Figure 2, it can be seen that the hydrophobic inorganic oxides of Comparative Examples 1 to 3 prepared by applying the existing heat treatment method are completely mixed with water in water and separation performance evaluation, the hydrophobic performance is significantly reduced. .

On the other hand, thermogravimetric analysis of several mica samples for comparison of the chemical reformation of the surface-modified hydrophobic inorganic oxide using microwave and the hydrophobic inorganic oxide according to the modification by heat treatment in a conventional manner according to the present invention ( TGA) results are shown in FIG. 3. More specifically, after washing the mica and the mica modified by Example 1, and the mica modified by Comparative Example 1 after performing a separate surface modification process by measuring the modified organic matter content through TGA 3 is shown. As shown in FIG. 3, the organic matter content of the mica according to Comparative Example 1 modified through heat treatment in the conventional manner was almost unchanged by about 0.2 wt%, but the mica according to Example 1 modified using microwaves. The organic matter content of 2 wt% was more effectively confirmed that the silane coupling agent was modified on the surface of the mica.

Claims (7)

a) coating the inorganic oxide surface with a silane coupling agent, and
b) irradiating the coated inorganic oxide with microwave at 300 to 700 MHz
Lt; / RTI >
The inorganic oxide is at least one member selected from the group consisting of titania, pearl, mica, and clay, and the silane coupling agent is propyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimeth At least one selected from the group consisting of oxysilane and octadecyltrimethoxysilane,
The content of the silane coupling agent in the coating step is 1 to 20 parts by weight based on the weight of the inorganic oxide,
The microwave irradiation time is 1 minute to 30 minutes to produce a hydrophobic inorganic oxide. The method of claim 1,
The coating step is a method of producing a hydrophobic inorganic oxide is carried out by the impregnation method, spray method, or ball mill method. delete delete delete delete delete

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