JPH0645451B2 - Titania / silica composite and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a novel titania / silica composite and a method for producing the same. In particular, the present invention provides a titania / silica composite having excellent properties as a filler required to be opaque by filling or coating on paper, paint or plastic rubber.

<Prior Art> Titanium oxide has been conventionally used as a filler for imparting opacity. However, titanium oxide has an oil absorption of 15 to 30.
It is about 100 ml / ml. For this reason, when the titanium oxide is filled in the paper, the printability of the paper is deteriorated, and when it is mixed with the paint, the sedimentation stability is deteriorated, so that the titanium oxide alone rarely exhibits a sufficient filling effect. Therefore, in general, it is often used in combination with finely divided silica. However, since the fine silica powder has a small refractive index of 1.4 to 1.6, when the fine silica powder is used as a filler in combination with paper, the in-pay property is small, which is a practical difficulty.

<Problems to be Solved by the Invention and Means for Solving the Problems> The present invention is to improve the above-mentioned drawbacks of the prior art. In particular, it imparts opacity, oil absorption is 100 ml / 100 g or more, and refractive index is 1.6. It is intended to provide the above-mentioned filler.

The present inventor has conducted extensive studies to achieve the above object. As a result, titania obtained by a specific manufacturing method /
It was confirmed that the silica composite had excellent filler properties, and further research was conducted to complete and provide the present invention.

That is, the present invention has a primary particle size of 10 to 100 nm, an opacity of 0.5 to 30 as measured by a volume method, and an oil absorption of 10
It is an amorphous titania / silica composite having 0 ml / 100 g to 300 ml / 100 g, a specific surface area of 50 to 400 m ² / g, and a titania content of 0.5 to 30 wt% with respect to silica.

In the present invention, an acidic non-solution of titanium is added to an aqueous alkali silicate solution in the presence or absence of titanium oxide so as to have a pH of 1 to 7 by spending at least 30 minutes or more.
Also provided is a process for producing a titania / silica composite, which comprises heating to a temperature of 0 ° C. to the boiling point of the aqueous solution.

In the present invention, the opacity measured by the volume method,
Spread a paper with black dots on the bottom of a graduated cylinder with an internal volume of 100 ml, mix 2 g of the filler sample with 100 ml of lacquer paint (clear lacquer for wood), and gradually add the paint in which the sample is dispersed into the graduated cylinder. The total volume (ml) of the coating material is measured when the black spots are no longer visible, and this volume is displayed. Therefore, the smaller the value of the opacity measured by the volumetric method in the present invention, the more the opacity of the filler sample is imparted.

The titania / silica composite provided by the present invention needs to have an opacity measured by a volumetric method in the range of 0.5 to 30. If the opacity is set to be less than 0.5, it is difficult to industrially produce the titania / silica composite, or even if it is possible, the cost is significantly increased, which is not preferable from an industrial viewpoint. If the opacity exceeds 30, the opacity which is the object of the present invention cannot be satisfied, which is not preferable.

Further, the titania / silica composite provided in the present invention is a solid substance having a primary particle diameter of 10 to 100 nm and having a cohesive property. The primary particle size affects the oil absorption amount and the specific surface area described later, and is controlled exclusively by various conditions in the process of producing the titania / silica composite.
When the primary particle size is smaller than 10 nm, it is difficult to form the composite having an oil absorption amount of 100 ml / 100 g or more described later, and when it is larger than 100 nm, the specific surface area of the composite becomes smaller than 50 m ² / g. It is not preferable because the sedimentation stability of the complex is poor.

Further, the titania / silica composite provided in the present invention preferably has an oil absorption of 100 ml / 100 g to 300 ml / 100 g. The oil absorption is 100 ml / 100
When it is less than g, the printability is not sufficient and the sedimentation stability cannot be kept good when mixed with a paint. On the contrary, a titania / silica composite having an oil absorption of more than 300 ml / 100 g is not suitable because it is difficult to manufacture and technically difficult, resulting in an increase in cost.

Further, the titania / silica composite provided in the present invention preferably has a specific surface area of 50 to 400 m ² / g. When the specific surface area is less than 50 m ² / g, the oil absorption amount becomes small and the printability deteriorates, and when the rubber is filled, the auxiliary property becomes insufficient. On the contrary, the specific surface area is 400
When it is larger than m ² / g, the oil absorption amount decreases, the cohesive force between particles becomes strong, and the dispersibility of silica deteriorates, which is not preferable.

Furthermore, the refractive index of the titania / silica composite provided by the present invention has a specific refractive index of 1.665 or more and 2.6. However, the present method for measuring the refractive index cannot specify the refractive index of the complex because there is no suitable measuring solvent. The fact that the refractive index is larger than 1.665 can be confirmed by a measuring method in which 1-bromonaphthalene solution is used as a solvent and Abbe refractometer measures temperature and refractive index.
When the refractive index is smaller than 2.6, it can be confirmed by comparing with the refractive index of titanium oxide.

Further, the titania / silica composite of the present invention has a composition of titania in the range of 0.5 to 30% by weight based on silica. When the titania is less than 0.5% by weight, the opacity disappears, and when it is 30% by weight or more, the opacity is not significantly different and the cost is increased, which is not economically preferable.

It can be confirmed from the chart of X-ray measurement that the complex in the present invention is amorphous. However, it is not clear in what form the titania and the silica constituting the composite exist mutually. Generally, a mixture of titania and silica can be separated by layer separation such that titania is in the lower layer and silica is in the upper layer by filtering with a Buchner, but the composite of the present invention cannot make such a distinction. Moreover, it can be confirmed that there is only one specific refractive index. From such observation, whether the titania and silica of the complex of the present invention are bonded to each other to form a single compound,
It is presumed to be either a microblend having the above properties or a mixture of both forms.

A typical embodiment of the method for producing the titania / silica composite of the present invention is as follows.

That is, in the presence or absence of titanium oxide, an acidic aqueous titanium solution is added to the alkaline silicate aqueous solution at a temperature of 80 ° C.
It can be produced by heating to the boiling temperature of the aqueous solution.

The titanium oxide is not particularly limited and may be either rutile type or anatase type. The amount of the alkali silicate aqueous solution is not particularly limited, but generally a sodium silicate aqueous solution or a potassium silicate aqueous solution is preferably used. The molar concentration of the aqueous alkali silicate solution is not particularly limited, but it is generally preferable to select it from the molar ratio range of 2.0 to 3.4.

Furthermore, as the acidic aqueous solution of titanium used in the present invention, known ones can be used without particular limitation. Generally, for example, an acidic aqueous solution of titanium with hydrochloric acid, an acidic aqueous solution of titanium with sulfuric acid, an aqueous solution of titanium tetrachloride, and the like are preferably used. Generally, the titanium concentration is 1 to 8%, preferably 3 to 5%, and the acidic concentration is 1%.
It is suitable to use in the range of 0 to 30%, preferably 20 to 24%.

When manufacturing the titania / silica composite of the present invention, the most important thing is to prepare an alkali silicate aqueous solution in the presence or absence of titanium oxide in advance, and add an acidic aqueous solution of titanium to the alkali silicate aqueous solution. is there. The addition time of the acidic aqueous solution of titanium is also an important requirement, and generally, at least 30 minutes or more is spent to prepare the aqueous solution of alkali silicate.
It must be added so that the pH is 1-7. Furthermore, when the acidic aqueous solution of titanium is added to the alkaline silicate aqueous solution or the alkaline silicate aqueous solution, or after the acidic aqueous solution of titanium is added, the aqueous solution is heated at a temperature of 80 ° C. to the boiling point of the aqueous solution.

Specifically, the aspect of the above-mentioned manufacturing method is preferably the following aspect.

(A) The acidic aqueous solution of titanium necessary for the pH to be 1 to 7, preferably 2.5 to 5.5 is added to the alkaline silicate aqueous solution.
Keeping in the alkali silicate aqueous solution at 0 ° C or higher for 30 minutes to 1
Method of adding for about 20 minutes, preferably as slowly as possible.

(B) An acidic aqueous solution of titanium necessary for neutralizing 25 to 50% of the alkaline silicate aqueous solution at 20 to 50 ° C. is added for 5 to 20 minutes or longer. In this state, there is no precipitation of particles of silica, titania or titania / silica composite. Of course, when the above reaction is carried out in the presence of titanium oxide in advance, the titanium oxide is in a dispersed state. Then, the remaining acidic aqueous solution of titanium is added to the above aqueous solution for 40 minutes to 120 minutes or longer so that the final pH of the aqueous solution is 1 to 7, preferably 2.5 to 5.5, and the temperature is kept at 80 ° C. or higher. How to add at temperature.

In the above method, heating at a temperature of 80 ° C. or higher to the boiling point of the aqueous solution is preferably maintained at the above temperature during the reaction, but as shown in the above (b), the temperature may be increased before the reaction. In some cases, it is preferable to carry out heating without heating.
Therefore, it is preferable to determine in advance according to the manufacturing conditions of the titania / silica composite, and to carry out.

The titania / silica composite obtained by the above method is obtained as a solid substance having the above-mentioned properties. These solid substances may be crushed as needed before use.

<Effect> The titania / silica composite of the present invention not only imparts excellent opacity as described above, but also serves as a filler having a large oil absorption and a large refractive index. Therefore, it is preferably used in fields where silica and titania have been conventionally used, for example, as fillers for papers, fillers for paints, reinforcing fillers for rubbers, and the like.

<Examples> In order to more specifically describe the present invention, examples will be described below, but the present invention is not limited to these examples.

The methods for measuring various properties measured in the examples are as follows.

(I) Single particle diameter Measured with a transmission electron microscope.

(Ii) Specific surface area Measured by a simple BET method.

(Iii) Oil absorption amount Measured by the JIS K5101 pigment test method.

(Iv) Opacity On the bottom of a graduated cylinder with an internal volume of 100 ml, lay a piece of white paper with black dots on it and disperse 2 g of the sample in lacquer paint (clear lacquer for wood (Kansai Paint Co., Ltd., Selva No. 61)). Then, this lacquer paint was gradually put into the graduated cylinder, and the total volume (ml) of the put paint when the black dots disappeared was measured.

(V) Refractive index Samples 1 to 2 g are put into a test tube, and 5 to 10 ml of 1 bromonaphthalene solution is added to form a slurry. Next, a thermometer was put in the test tube, and after lightly stirring, the temperature was changed to 5 to 50 ° C., and the temperature when the solution turned red was measured. The refractive index was calculated from this temperature.

(Vi) Confirmation of Amorphousness The presence or absence of a crystal peak position was confirmed by an X-ray diffractometer.

Example 1 Commercially available sodium silicate SiO ₂ 48.99%, Na ₂ O 22.32
%, 710 ml and 5290 ml of water are charged into an external heating type reaction tank of 8 and stirred. Next, 17 g of titanium oxide and 382 m of titanium sulfate having a sulfuric acid concentration of 23% (TiO ₂ concentration of 40%).
l is added. After the addition, the temperature is raised to a reaction temperature of 95 ° C., and the mixture is stirred for 5 minutes in this state, and then 664 ml of titanium sulfate is added.
Is added in 90 minutes to adjust the pH of the reaction solution to 3.0 and the reaction is completed. The reaction solution was filtered, washed with water, dried and pulverized to obtain a titania / silica composite. The results are shown in Table 1.

Example 2 3157 ml of Glauber's salt having a Na ₂ O concentration of 1.9% in Example 1,
It was manufactured in the same manner except that 2133 ml of water was used. The results are shown in Table 1.

Example 3 Commercially available sodium silicate SiO ₂ 24.87%, Na ₂ O 7.63% 1
399 ml and 3157 ml of Glauber's salt with Na ₂ O concentration of 1.9%,
Add 1444 ml of water to the external heating type reaction tank and
The procedure of Example 1 was repeated except that 257 ml of titanium sulfate and 440 ml of second titanium sulfate were used. The results are shown in Table 1.

Example 4 Commercially available sodium silicate SiO ₂ 28.26%, Na ₂ O 9.50%,
1231 ml, Glauber's salt 3157 ml, and water 1612 ml were charged into an external heating type reaction tank, 161 ml of the titanium sulfate was added with stirring, the temperature was raised to 95 ° C., and the mixture was stirred for 5 minutes at this temperature, then 22% sulfuric acid was added. 650 ml to 90
The pH of the reaction solution was adjusted to 3.4 and the reaction was completed.

The subsequent steps were the same as in Example 1.

The results are shown in Table 1.

Example 5 Commercially available sodium silicate SiO ₂ 48.99%, Na ₂ O 22.32
%, 710 ml and 5290 ml of water are charged into an external heating type reaction tank of 8 and stirred. Next, 17 g of titanium oxide is added and well dispersed. After that, the temperature is raised and the reaction temperature is 95 ° C.
After that, 1046 ml of titanium sulfate having a sulfuric acid concentration of 23% (TiO ₂ concentration of 4.0%) was added in 120 minutes to adjust the pH of the reaction solution to 3.
The reaction was terminated as 1. The reaction solution was filtered, washed with water, dried and pulverized to obtain a titania / silica composite.

The results are shown in Table 1.

Comparative Example 1 Tokuseal P and Fineseal X, which are commercially available hydrous silicates
-40 (manufactured by Tokuyama Soda) Mizuka Seal P526 (manufactured by Mizusawa Chemical)
Table 1 shows the results of measuring the opacity of CYCIDE 244 (manufactured by Fuji Devison KK).

Comparative Example 2 Table 1 shows the measurement results of commercially available titanium oxide (manufactured by Titanium Industry Co., Ltd.) in the same manner as in Example 1.

Comparative Example 3 Production was carried out in the same manner as in Example 5, except that the reaction temperature was 50 ° C. The results are shown in Table 1.

Comparative Example 4 Commercially available sodium silicate SiO ₂ 24.87%, Na ₂ O 7.63% 1
930 ml and reagent Na ₂ OSO ₄ 687 g in water 4070 ml
The solution dissolved in is put into a reaction tank of external heating system,
Stage titanium sulfate 202ml, 2nd stage titanium sulfate 790ml
Was manufactured in the same manner as in Example 1 except that The results are shown in Table 1.

Comparative Example 5 The same procedure as in Example 5 was carried out except that the addition time of titanium sulfate was changed to 15 minutes. The results are shown in Table 1.

Claims (2)

[Claims] 1. A primary particle size of 10 to 100 nm, an opacity of 0.5 to 30 measured by a volume method, and an oil absorption of 10.
An amorphous titania / silica composite having 0 ml / 100 g to 300 ml / 100 g, a specific surface area of 50 to 400 m ² / g and 0.5 to 30% by weight of titania based on silica. 2. An acidic aqueous solution of titanium is added to an alkaline silicate aqueous solution in the presence or absence of titanium oxide so as to have a pH of 1 to 7, spending at least 30 minutes or more, and 8
A process for producing a titania / silica composite, which comprises heating to a temperature of 0 ° C. to the boiling point of the aqueous solution.