JPS5934646B2 - Method for producing fibrous inorganic filler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a fibrous inorganic filler, and aims to improve the reinforcing effect of the fibrous inorganic filler.

In summary, the production method of the present invention uses a CaO component raw material, an At2O three component raw material, and a Caso four component raw material at a mixing ratio of 1.
Calcium aluminate monosulfate hydrate (3C
a0-At203・CaS04・12H2O, hereinafter MS
H) is synthesized, and this MSH has a solid concentration of 10
% or less, add the caso4 component and water, stir, adjust the pH to 11.5-12.5, and prepare fibrous calcium aluminate trisulfate hydrate (3C
a0・At203・3CaS04・31~32H20,
Hereinafter abbreviated as TSH) filler is obtained.

Next, this invention will be explained in detail.

The synthesis of MSH consists of Ca(OH)2, At(OH)3 and C
Preferably, aSO4.2H20 is hydrothermally synthesized in an autoclave.

In this case, it is preferable to add water so that the water mixing ratio is 1.2 or more. A suitable reaction temperature is 175 to 185°C. It is necessary to synthesize TSH under the following conditions. Solid content concentration of MSH and gypsum (CaS04・2H20) (MSH+CaS04・2H20/water+M
It is necessary to keep SH+CaS04.2H2O) below 10%.

If this exceeds 10%, the growth into a fibrous form will be insufficient. Any type of gypsum may be used as long as it is selected so as to have the solid content concentration as described above. During the TSH reaction,
It is preferable to continue stirring to prevent particles of the raw material from settling.

However, rapid stirring is not preferred. In the 5TSH reaction, the pH of the system is preferably adjusted to 11.5 to 12.5.

More preferably, the pH is adjusted to 11.5.
When the pH is less than 1L5, MSH decomposes, and when it exceeds 12.5, growth into a fibrous form is inhibited. o The reaction temperature is T
When the SH conversion is carried out under normal pressure, it is preferable to adjust the temperature to normal temperature to 100°C.

It is preferable that the temperature is as high as possible. Under the above conditions, TSH
By carrying out the reaction, a fibrous TSH filler can be obtained.

The fibrous TSH filler obtained in this way was
For example, when blended with a thermoplastic resin or thermosetting resin, hardness and Young's modulus can be significantly improved. Moreover, when this is blended into an inorganic cured product, the bending strength can be improved. Next, preferred embodiments will be described.

Examples 1 to 7: MSH slurry (synthesized at a water mixing ratio of 1.8 and a temperature of 180°C) and CasO4.2H20 were mixed at a molar ratio of 1:2,
The solid content concentration of this was adjusted as shown in Table 1, and the pH was further adjusted as shown in Table 1 with 1/2N sulfuric acid while stirring, and the TSH conversion reaction was carried out at the temperature shown in Table 1.

All reactions were completed within 1 hour. In particular, in Example 1, the process was completed in 30 minutes. As a result, fibrous TSH fillers having the length and width shown in Table 2 were obtained. Then, this product was filtered and dried at 40°C. In this case, since the crystal form was fibrous, filtration could be easily performed.
Next, a reinforcement test was conducted using the fibrous TSH filler obtained in Example 1.

First, 25% of the fibrous TSH filler was added to polypropylene resin.
01) was added and kneaded and molded.

The resulting composite resin has a high hardness and an initial elastic modulus of 5.
Improved by 0%. Next, this fibrous TSH filler was used for reinforcing the inorganic cured body.

That is, MSH powder and CasO4.2H20 powder are mixed at a molar ratio of 1:2 and kneaded at a water mixing ratio of 1.0. At this time, 10(f) of fibrous TSH filler was added to MSH. As a result, the reaction rate became faster and the bending strength of the obtained inorganic cured product was improved by 5% compared to that without the addition.

Claims (1)

[Claims] 1 CaO component raw material, Al_2O_3 component raw material, and CaS
O_4 component raw material with water mixing ratio of 1.2 or more 175-18
Calcium aluminate monosulfate hydrate was synthesized by a hydrothermal reaction at 5°C, and CaSO_4 component and water were added to this calcium aluminate monosulfate hydrate so that the solid content concentration was 10% or less and stirred. A method for producing a fibrous inorganic filler, which comprises adjusting the pH to 11.5 to 12.5 to obtain fibrous calcium aluminate trisulfate hydrate.