JP2012121773A - Chestnut-like boehmite and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel boehmite and its method for manufacturing which has a workability of a material to be filled with a needle-like filler and has a chestnut shape oriented three dimensionally in the material to be filled and excellent in filling property, and to provide a resin composition material which is enhanced in physical property by adding the filler.SOLUTION: The boehmite includes the chestnut-like shape consisting of a plurality of the combined needle-like fragments. The method manufactures the chestnut-like boehmite including as a raw material, aluminium hydroxide, magnesium sulfate as a first additive and as a second additive, one or more selected from sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium hydroxide, wherein the compounding quantity of magnesium sulfate as a mole ratio is 0.1-0.5 to 1 mole of aluminium hydroxide, and compounding quantity of the second additive as a mole ratio is 0.5-1.2 to 1 mole of magnesium sulfate. The raw material is hydrothermally reacted at 200-250°C in the presence of water.

Description

  The present invention relates to a boehmite having a novel shape and a method for producing the same, and more particularly to a boehmite in which a large number of needle-like pieces are bound to form a round shape and a method for producing the boehmite.

Boehmite has a chemical composition of AlO (OH) or Al ₂ O ₃ · H ₂ O, and is a chemically stable alumina monohydrate generally produced by hydrothermal treatment of alumina trihydrate. It is used as a flame retardant filler such as plastic products such as electronic boards, rubber, adhesives, paints, reinforcing fillers, fillers for suppressing expansion, and fillers for heat conduction. In addition, it is used in various applications such as paint and cosmetic glitter fillers, catalyst carriers, alumina raw materials, and paper coating fillers. Boehmite can be controlled to have various shapes such as a plate shape, a needle shape, and a cube shape by adjusting the production conditions of the hydrothermal treatment. Plate-like boehmite and needle-like boehmite having a high aspect ratio can increase mechanical strength such as tensile strength, bending strength, and elastic modulus of the filling material. In particular, conventional acicular boehmite (see Patent Literature 1 and Patent Literature 2) has not only a high aspect ratio but also a large specific surface area, so that the above effect is excellent.

JP 2003-54941 A JP 2008-37741 A

  However, conventional needle boehmite increases the viscosity of the filling material and lowers the fluidity when filling the filling material, so that the workability of the filling material is deteriorated and a desired filling amount is obtained. There was a problem that it was not possible. In addition, extrusion molding is generally widely used to combine the material to be filled and acicular boehmite. In these moldings, the acicular boehmite is oriented only in a specific direction (extrusion direction, resin flow direction). There is a problem that the effect such as two-dimensional (planar) and three-dimensional (three-dimensional) reinforcement cannot be expected. In addition, although the safety of boehmite has been established, needle-shaped boehmite has a needle-like shape, so there is a possibility that it will be stabbed into the body when inhaled. In general, the use tended to be avoided.

The present invention has been made in view of the above-described circumstances, and has a needle-like shape with good workability, excellent fillability, and a three-dimensionally oriented shape that is three-dimensionally oriented to the filling material. It is an object to provide a simple boehmite. It is another object of the present invention to provide a new boring shape that is needle-shaped but reduces the possibility of being stuck in the body when inhaled.
Furthermore, it aims at providing the manufacturing method of boehmite of the shape of a saw-tooth shape. It is another object of the present invention to provide a resin composition in which physical properties imparted by a filler are enhanced.

In order to solve the above-mentioned problems, the present inventors have intensively studied to arrive at the present invention.
That is, the gist of the invention according to claim 1 is a boring boehmite characterized in that a large number of needle-like pieces are bundled to form a boring shape.

  The invention according to claim 2 is any one selected from aluminum hydroxide, magnesium sulfate as the first additive, and sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium hydroxide as the second additive. The compounding amount of magnesium sulfate is 0.1 to 0.5 as a molar ratio with respect to 1 mol of aluminum hydroxide, and the compounding amount of the second additive is 0.5 as a molar ratio with respect to 1 mol of magnesium sulfate. The gist of the above-mentioned method of boring boehmite is characterized in that the raw material of ~ 1.2 is subjected to hydrothermal reaction at 200 ° C to 250 ° C in the presence of water.

  The gist of the invention described in claim 3 is a resin composition characterized by being filled with the above-mentioned sagittal boehmite.

According to this invention comprised as mentioned above, there exist the following effects. According to the sawtooth boehmite of the present invention, since it has a needle shape, the effect of the conventional needle boehmite is exhibited.
According to the sawtooth boehmite of the present invention, the fluidity of the filling material is higher than that of the conventional acicular boehmite, so that the workability of the filling material is excellent, and the productivity of the product can be increased.
According to the sawtooth boehmite of the present invention, the filling material has higher fluidity than conventional acicular boehmite, so the filling property is excellent, and the effects such as reinforcement and thermal conductivity imparted to the filling material are enhanced. As a result, the physical properties of the object to be filled can be improved. According to the sagittal boehmite of the present invention, since it is oriented three-dimensionally to the filling material, it is possible to enhance the effects such as reinforcement and thermal conductivity imparted to the filling material, and consequently the physical properties of the filling material. Can be increased. According to the sagittal boehmite of the present invention, a large number of needle-like pieces are bundled to form a corrugated shape, so that the possibility of being stuck in the body when inhaling conventional acicular boehmite can be reduced, and thus safety Is increased. According to the method for manufacturing a sawtooth boehmite of the present invention, a sawtooth boehmite can be manufactured efficiently and reliably. According to the resin composition of this invention, the physical property provided with fillers, such as reinforcement and heat conductivity, is improved.

2 is an electron micrograph image of boehmite of Example 2. 4 is an electron micrograph image of boehmite of Example 4. 7 is an electron micrograph image of boehmite of Example 7. It is an electron micrograph image of boehmite of Example 13. 18 is an electron micrograph image of boehmite of Example 15. 18 is an electron micrograph image of boehmite of Example 16. 4 is an electron micrograph image of boehmite of Comparative Example 3. 6 is an electron micrograph image of boehmite of Comparative Example 5. It is an electron micrograph image of a fracture surface of a resin filled with sawtooth boehmite.

  The scooping boehmite of the present invention is needle-shaped and has a scooping shape in which a large number of needle-like pieces are bound. Therefore, the filling material has higher fluidity than conventional acicular boehmite and is three-dimensionally oriented to the filling material.

  The sagittal boehmite of the present invention is any one selected from aluminum hydroxide, magnesium sulfate as the first additive, and sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium hydroxide as the second additive. The above can be produced by hydrothermal reaction in the presence of water. The average particle size of the aluminum hydroxide used is preferably 75 μm or less, and more preferably 1 μm to 75 μm. When the average particle size of aluminum hydroxide is less than 1 μm, the needle-like pieces are difficult to bind. Boehmite may not be obtained. Commercially available aluminum hydroxide can be used.

  Magnesium sulfate is used as the first additive. Magnesium sulfate may be an anhydride or a hydrate represented by a heptahydrate, but the heptahydrate is preferable from the viewpoint of economy and solubility. The first additive can lengthen the needle-like pieces of gargle boehmite. A commercially available magnesium sulfate can be used. As for the compounding quantity of magnesium sulfate, 0.1-0.5 is preferable at the molar ratio with respect to 1 mol of aluminum hydroxide. If the molar ratio of magnesium sulfate is less than 0.1, plate-like or cubic boehmite is likely to be formed, and burrow-like boehmite may not be obtained. It is an economy.

  The second additive may be a hydroxide of the first group element or the second group element, but any one selected from relatively inexpensive sodium hydroxide, potassium hydroxide, calcium hydroxide, and magnesium hydroxide One or more are preferred. When the second additive coexists with magnesium sulfate, the shape of boehmite can be garnished, and sedimentation when adjusting the raw material slurry can be prevented, thereby increasing productivity. As the second additive, any commercially available one can be used. As for the compounding quantity of a 2nd additive, 0.5-1.2 are preferable at the molar ratio with respect to 1 mol of magnesium sulfate. When the molar ratio of the second additive is less than 0.5, the reaction time becomes longer, and a large number of needle-like pieces are not bundled and may become loose conventional needle-like boehmite. On the other hand, when the molar ratio exceeds 1.2, plate-like boehmite may be mixed, and it may not be possible to obtain garlic boehmite.

  Scorched boehmite can be produced by hydrothermal reaction of the above raw materials in the presence of water. The amount of water added is not particularly limited as long as the raw material can be adjusted to a slurry. The hydrothermal reaction is preferably performed at 200 to 250 ° C. under pressure in a pressure device such as an autoclave. If the reaction temperature is less than 200 ° C., the reaction time may be long, or the corrugated boehmite may not be obtained. Although it may exceed 250 ° C., expensive high-pressure equipment is required, and it is uneconomical in terms of energy. During the reaction, the slurry may or may not be stirred. The reaction time is preferably in the range of 3 hours to 24 hours. If it is less than 3 hours, garlic boehmite may not be obtained. Moreover, even if it exceeds 24 hours, there is no special effect and it is uneconomical in terms of energy.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not limited to the following Example.

[Manufacture of boehmite]
Aluminum hydroxide (Examples 1 to 9, Example 12 to Example 17, Comparative Example except Comparative Example 9 (Nippon Light Metal Co., Ltd., B303, average particle size: 30 μm), Examples 10 and 11, Comparative Example 9 (Nippon Light Metal Co., Ltd., B53, average particle size: 50 μm), Example 18 (Nippon Light Metal Co., Ltd., BF-013, average particle size: 1 μm), Example 19 (Sumitomo Chemical Co., Ltd., C-301, average) Particle size: 1 μm), Example 20 (manufactured by Sumitomo Chemical Co., C-303, average particle size: 3 μm), Example 21 (manufactured by Nippon Light Metal Co., Ltd., BF-083, average particle size: 8 μm), Example 22 ( Nippon Light Metal Co., Ltd., B153, average particle size: 15 μm)) and magnesium sulfate heptahydrate (manufactured by Kanto Chemical Co.) as the first additive shown in Tables 1 and 2 below, and Tables 1 and 2 below. 2nd additive (sodium hydroxide (manufactured by Kanto Chemical Co., Inc.), potassium hydroxide Kanto Chemical), calcium hydroxide (Kanto Chemical), magnesium hydroxide (Kanto Chemical), sodium sulfate (Kanto Chemical), sodium chloride (Kanto Chemical), sodium carbonate (Kanto Chemical) 500 ml of water was added to the raw materials blended at a predetermined ratio, and a hydrothermal reaction was performed at 205 ° C. (temperature rising time: 2 hours) for 12 hours using a 300 L autoclave. After completion of the reaction (pressure reduction time: 2 hours), the reaction product was filtered, washed with water and pulverized to obtain a predetermined boehmite. The shape of the obtained boehmite was observed using an electron microscope. The electron micrograph image of the Example and the comparative example was shown in FIGS. In Table 2, sodium sulfate, sodium chloride and sodium carbonate are included in the second additive for convenience.

  As shown in Table 1 and FIGS. 1 to 6, in the examples, garnet boehmite could be obtained. In the table, some plate-like boehmite is mixed with Δ-corner boehmite, but there is no problem in using it as the potato-boehmite. On the other hand, as shown in Table 2 and FIGS. 7 and 8, no garnet boehmite was obtained in the comparative example. The ▲ indicates that some boring boehmite is mixed in the plate boehmite, but there is a problem in using it as a boring boehmite.

[Resin kneading test]
A resin kneading test was conducted on an epoxy resin (Dow Chemical Company, DER * 331J) using each of the sagittal boehmite and needle boehmite (BMI, manufactured by Kawai Lime Industry Co., Ltd.) of Example 6. In a beaker, 50 g of epoxy resin and 1 g of 2-ethyl-4-methylimidazole (manufactured by Wako Pure Chemical Industries, Ltd.) as a curing agent were placed, and stirred well while maintaining at 70 ° C. with a hot stirrer. Thereto was gradually added 21 g of bog boehmite, and the end point was the point at which the stirrer could not be stirred. By the same method, 9 g of acicular boehmite was gradually added, and the point at which the stirrer could be stirred was defined as the end point. After mixing, the epoxy resin was poured into the mold and thoroughly defoamed, and then cured by heating for 2 hours with a dryer at 175 ° C.

As a result of the test, the sagittal boehmite was able to fill 42 parts by weight with respect to the epoxy resin.
On the other hand, acicular boehmite was able to fill 18 parts by weight with respect to the epoxy resin. From this fact, it was found that the garlic boehmite has a higher filling property than the needle boehmite. Moreover, as shown in FIG. 9, as a result of observing the fracture surface of the resin filled with the sawtooth boehmite with an electron microscope, the sawtooth boehmite was three-dimensionally oriented in the resin.

  The present invention can be applied to the fields of synthetic resin, rubber, adhesive, paint, etc. in which boehmite is used as a filler.

Claims (3)

  A vaginal boehmite characterized in that a large number of needle-like pieces are bundled to form a vaginal shape.   Containing one or more selected from aluminum hydroxide, magnesium sulfate as the first additive, sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium hydroxide as the second additive, The blending amount is 0.1 to 0.5 in a molar ratio with respect to 1 mole of aluminum hydroxide, and the blending amount of the second additive is a raw material having a molar ratio with respect to 1 mole of magnesium sulfate is 0.5 to 1.2. The method for producing a scooped boehmite according to claim 1, wherein a hydrothermal reaction is carried out at 200 ° C to 250 ° C in the presence of water.   A resin composition, which is filled with the sagittal boehmite according to claim 1.

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