JP2011105540A - Surface-treated gibbsite type aluminum hydroxide particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide surface-treated gibbsite type aluminum hydroxide particles which exhibit higher flame retardancy and generate small kneading torque when filled into a resin. <P>SOLUTION: The surface-treated gibbsite type aluminum hydroxide particles are obtained by surface-treating gibbsite type aluminum hydroxide particles with silicone oil, wherein the gibbsite type aluminum hydroxide particles have an average primary particle diameter of 0.01-0.3 μm, a DOP oil absorption of 90-300 mL/100 g and an average secondary particle diameter of 0.1-10 μm, and wherein an amount of the silicone oil used is 0.5-4 pts.wt. in the surface-treated gibbsite type aluminum hydroxide particles. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to surface-treated gibbsite-type aluminum hydroxide particles, and more particularly to surface-treated gibbsite-type aluminum hydroxide particles suitably used as a flame retardant filled in a resin.

Gibbsite type aluminum hydroxide particles are useful as a flame retardant filled in a resin. For example, Patent Document 1 (Japanese Patent Laid-Open No. 3-8715) discloses a gibbsite type hydroxide having an average primary particle size of 0.15 μm or less. It is disclosed that aluminum particles can be used as a flame retardant.

However, as the gibbsite type aluminum hydroxide particles, those having better flame retardancy are required, and those having a small kneading torque generated when filled into a resin are required.

JP-A-3-8715

Therefore, the present inventors have intensively studied to develop gibbsite-type aluminum hydroxide particles that exhibit higher flame retardancy and generate a small kneading torque when filled in a resin, resulting in the present invention.

That is, the surface-treated gibbsite-type aluminum hydroxide particles of the present invention are surface-treated gibbsite-type aluminum hydroxide particles in which the surface of the gibbsite-type aluminum hydroxide particles is surface-treated with silicone oil,
The gibbsite type aluminum hydroxide particles have an average primary particle size of 0.01 to 0.3 μm, a DOP oil supply amount of 90 to 300 mL / 100 g, and an average secondary particle size of 0.1 to 10 μm. ,
The amount of the silicone oil used is 0.5 to 4 parts by weight in the surface-treated gibbsite type aluminum hydroxide.

The surface-treated gibbsite type aluminum hydroxide particles of the present invention are more useful as a flame retardant used by being filled in a resin because they exhibit higher flame retardancy and a small kneading torque generated when filled in the resin.

<Surface treatment Gibbsite type aluminum hydroxide particles>
The surface-treated gibbsite type aluminum hydroxide particles of the present invention are obtained by surface-treating the surface of gibbsite type aluminum hydroxide particles with silicone oil. Aluminum hydroxide particles having a gibbsite-type crystal structure as a main crystal phase and a compound represented by the chemical formula Al ₂ O ₃ .3H ₂ O. The crystal structure can be examined by a powder X-ray diffraction method (powder XRD method).

The average primary particle diameter of the gibbsite type aluminum hydroxide particles in the present invention is 0.01 to 0.3 μm, preferably 0.03 μm or more and 0.2 μm or less, more preferably 0.1 μm or less. When the average primary particle diameter is less than 0.01 μm or exceeds 0.3 μm, sufficient flame retardancy is not exhibited. The average primary particle diameter can be measured from a micrograph obtained by, for example, a transmission electron microscope (TEM).

The DOP oil absorption is 90 to 300 mL / 100 g, preferably 100 to 180 mL / 100 g. If the DOP oil absorption is less than 90 mL / 100 g, the flame retardancy tends to be insufficient, and if it exceeds 300 mL / 100 g, when added to a heat-melted resin, its fluidity decreases and molding is difficult. Tend to be.

The average secondary particle diameter of the gibbsite type aluminum hydroxide particles in the present invention is 0.01 to 10 μm. The average secondary particle size can be measured by dispersing aluminum hydroxide particles in water and using a laser scattering particle size distribution meter. When the average secondary particle diameter exceeds 10 μm, it is easy to obtain a resin composition having poor physical properties when filled in the resin.

The BET specific surface area of the gibbsite-type aluminum hydroxide particles in the present invention is preferably 15 to 100 m ² / g.

The gibbsite-type aluminum hydroxide particles in the present invention are produced by, for example, a method in which aluminum hydroxide is precipitated by partially neutralizing a sodium aluminate aqueous solution to form an aluminum hydroxide slurry, and the slurry is aged at 40 to 90 ° C. can do.

The aluminum content of the sodium aluminate aqueous solution is usually 100 to 150 g / L in terms of Al ₂ O _{3 based on} the aqueous solution, and the sodium content is usually 100 to 100 in terms of Na ₂ O based on the aqueous solution. 150 g / L.

For partial neutralization, for example, an aluminum acid salt may be added. An aluminum acid salt is a salt in which an aqueous solution obtained by dissolving this alone in water exhibits acidity, and examples thereof include aluminum sulfate, aluminum chloride, and aluminum nitrate. The amount (W) of aluminum acid salt used is such that aluminum hydroxide can be precipitated without completely neutralizing the sodium aluminate aqueous solution. Specifically, the sodium aluminate aqueous solution is completely neutralized. The neutralization molar ratio (= W / W ₀ ) shown as the use amount ratio to the use amount (W ₀ ) of the aluminum acid salt required for this is about 0.3 to 0.7. The temperature at the time of adding aluminum acidic salt is about 0-40 degreeC normally. The aluminum acid salt is preferably added with stirring.

By adding an aluminum acid salt, the aqueous sodium aluminate solution is neutralized, aluminum hydroxide is precipitated, and an aluminum hydroxide slurry in which aluminum hydroxide is dispersed in water is obtained.

The resulting aluminum hydroxide slurry is aged. Aging is performed by heating to 40-90 ° C. The time required for aging is usually about 5 hours to 7 days. By aging, the precipitated aluminum hydroxide gradually becomes gibbsite, and the gibbsite-type aluminum hydroxide particles in the present invention can be obtained.

The obtained gibbsite-type aluminum hydroxide particles can be taken out as a solid content after, for example, centrifuging the slurry after aging and performing solid-liquid separation. The taken gibbsite-type aluminum hydroxide particles are preferably further washed with an alcohol such as pure water or methanol to remove sodium.

By stirring the obtained gibbsite type aluminum hydroxide particles and silicone oil with a stirrer or the like, the surface of the gibbsite type aluminum hydroxide particles is surface-treated with silicone oil, and surface treated gibbsite type aluminum hydroxide particles are obtained. The usage-amount of silicone oil is 0.5-4 weight part in surface treatment gibbsite type aluminum hydroxide. The surface-treated gibbsite-type aluminum hydroxide particles of the present invention thus obtained exhibit higher flame retardancy, and since the kneading torque generated when filling the resin is small, the flame retardant used by being filled in the resin Useful as.

As the resin, a thermoplastic resin or a thermosetting resin is used.
Examples of the thermoplastic resin include olefin homopolymers such as polyethylene, polypropylene, and polybutene, ethylene-propylene random copolymers, ethylene-propylene block copolymers, propylene-butene random copolymers, and propylene-butene block copolymers. Olefin resins such as olefin copolymers such as ethylene-propylene-butene copolymer, aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyesters such as polycaprolactam and polyhydroxybutyrate, nylon-6, nylon-66 , Polyamides such as nylon-10, nylon-12, and nylon-46.

Examples of the thermosetting resin include epoxy resin, vinyl ester resin, phenol resin, unsaturated polyester resin, polyimide, polyurethane, and melamine resin.

The filling amount of the surface-treated gibbsite type aluminum hydroxide particles is usually about 30 to 150 parts by weight per 100 parts by weight of the resin.

The filling method for filling the resin with the surface-treated gibbsite-type aluminum hydroxide particles is not particularly limited, and is appropriately selected according to the type of the resin. For example, the surface-treated gibbsite-type aluminum hydroxide particles of the present invention may be applied to a thermoplastic resin. Is filled with the surface-treated gibbsite type aluminum hydroxide particles of the present invention, heated and melt-kneaded.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by this Example.

In each Example, the DOP oil absorption amount of the obtained gibbsite type aluminum hydroxide particles was changed to DOP (dioctyl phthalate) instead of DBP (dibutyl phthalate) in JIS K6221 (1982) oil absorption amount B method (slag kneading method). ) Was used according to the same method except that
The average primary particle size was determined from a transmission electron micrograph.
The main crystal phase was determined from the peak showing the highest relative peak intensity in the X-ray diffraction spectrum determined using an X-ray diffractometer [manufactured by Rigaku Corporation, “RAD-RB RU-200”].
The average secondary particle size was determined by dispersing the gibbsite-type aluminum hydroxide particles in pure water and obtaining a particle size distribution curve with a laser scattering type particle size distribution analyzer (“Microtrac HRA” manufactured by Reed and Northrup). % Particle diameter.
The BET specific surface area was determined by a nitrogen adsorption method (JIS Z 8830).
The flame retardancy was evaluated by molding a 1 mm thick resin composition and using this as a flame retardancy evaluation scale according to a vertical combustion test defined in UL-94 of the US UL standard.

Example 1
[Production of Gibbsite Type Aluminum Hydroxide Particles]
Aluminum sulfate having a sodium content (Na ₂ O conversion) of 133 g / L and an aluminum content (Al ₂ O ₃ conversion) of 137 g / L in 1358 parts by weight of an aqueous sodium aluminate solution at 30 ° C. When 537 parts by weight of the aqueous solution was added, aluminum hydroxide was precipitated. Then, it stirred for 60 minutes at the same temperature. The amount of aluminum sulfate used is 0.5 times the amount required to completely neutralize the sodium aluminate aqueous solution.

Next, 500 parts by weight of pure water was added, heated to 60 ° C., allowed to stand at the same temperature for 4 days and aged, cooled to room temperature (about 25 ° C.), solid-liquid separated by centrifugation, Removed the minute. The obtained solid content was washed by adding 3990 parts by weight of pure water, stirring, and repeating solid-liquid separation by centrifugation three times. The solid content after washing was dried at 120 ° C. in the atmosphere and pulverized by a pulverizer [Nara Machinery Co., Ltd., “free pulverizer”] to obtain gibbsite type aluminum hydroxide particles.

The obtained gibbsite-type aluminum hydroxide particles had a DOP oil absorption of 112 mL / 100 g, an average primary particle diameter of approximately 0.2 μm, and the main crystal phase was a gibbsite-type. Moreover, the average secondary particle diameter was 0.4 μm, secondary particles having a particle diameter exceeding 105 μm were not included, and the BET specific surface area was 17 m ² / g.

〔surface treatment〕
After mixing 3 parts by weight of silicone oil (“SH200-50cs” manufactured by Toray Dow Corning Co., Ltd.) with 97 parts by weight of the gibbsite type aluminum hydroxide particles obtained above, a Henschel mixer (manufactured by Kawata Seisakusho, “ The surface-treated gibbsite-type aluminum hydroxide particles were obtained by stirring for 30 minutes at a set temperature of 110 ° C. and a rotational speed of 1200 rpm with a “super mixer”).

Example 2
The same operation as in Example 1 was performed except that 1 part by weight of silicone oil (“SH200-100cs” manufactured by Toray Dow Corning Co., Ltd.) was mixed with 99 parts by weight of the gibbsite-type aluminum hydroxide particles obtained in Example 1. And surface treated gibbsite type aluminum hydroxide particles were obtained.

Example 3
The same operation as in Example 1 was performed except that 3 parts by weight of silicone oil (“SH200-100cs” manufactured by Toray Dow Corning Co., Ltd.) was mixed with 97 parts by weight of the gibbsite-type aluminum hydroxide particles obtained in Example 1. And surface treated gibbsite type aluminum hydroxide particles were obtained.

Comparative Example 1
The same operation as in Example 1 was conducted except that 5 parts by weight of silicone oil (“SH200-100cs” manufactured by Toray Dow Corning Co., Ltd.) was mixed with 95 parts by weight of the gibbsite-type aluminum hydroxide particles obtained in Example 1. And surface treated gibbsite type aluminum hydroxide particles were obtained.

Comparative Example 2
The same operation as in Example 3 was performed except that aluminum hydroxide particles having a DOP oil absorption of 47 ml / 100 g (“C-303” manufactured by Sumitomo Chemical Co., Ltd.) were used as gibbsite-type aluminum hydroxide particles in Example 3. Thus, surface-treated gibbsite type aluminum hydroxide particles were obtained.

Example 4
[Evaluation]
200 parts by weight of the surface-treated gibbsite type aluminum hydroxide particles obtained in Example 1, 100 parts by weight of an ethylene-vinyl acetate copolymer (manufactured by Sumitomo Chemical Co., Ltd., “Evert H-2031”), and an antioxidant (Ciba Specialty) A mixture obtained by mixing 1 part by weight of “IRGANOX1010” manufactured by Tea Chemical Co., Ltd. was kneaded at a set temperature of 160 ° C. and a screw rotation speed of 40 rpm using a kneader (Toyo Seiki Co., Ltd., “Lab Plast Mill”). A kneaded product was obtained. This kneaded product was press-molded at 190 ° C., made 1 mm thick, and then cut out to obtain a resin composition. The evaluation results are shown in Table 1.

Example 5
A resin composition was obtained in the same manner as in Example 4 except that 200 parts by weight of the surface-treated gibbsite-type aluminum hydroxide particles in Example 2 were used. The evaluation results are shown in Table 1.

Comparative Example 3
A resin composition was obtained in the same manner as in Example 4 except that 200 parts by weight of the surface-treated gibbsite type aluminum hydroxide particles of Comparative Example 1 were used. The evaluation results are shown in Table 1.

Comparative Example 4
200 parts by weight of gibbsite-type aluminum hydroxide particles before the surface treatment in Example 1, 100 parts by weight of an ethylene-vinyl acetate copolymer (manufactured by Sumitomo Chemical Co., Ltd., “Evert H-2031”), and an antioxidant ( A resin composition was obtained in the same manner as in Example 4 except that 1 part by weight of “IRGANOX1010” manufactured by Ciba Specialty Chemicals Co., Ltd. was mixed. The evaluation results are shown in Table 1.

Comparative Example 5
196 parts by weight of gibbsite type aluminum hydroxide particles before surface treatment in Example 1, 100 parts by weight of ethylene-vinyl acetate copolymer (manufactured by Sumitomo Chemical Co., Ltd., “Evert H-2031”), silicone oil (Toray A resin composition was prepared by mixing 6 parts by weight of Dow Corning, “SH200-100cs”) and 1 part by weight of an antioxidant (“IRGANOX1010”, manufactured by Ciba Specialty Chemicals) in the same manner as in Example 4. Obtained. The evaluation results are shown in Table 1.

注：上記第１表のＵＬ−９４の評価結果における規格外とは、可燃性側に外れることを意味する。
Table 1

Note: Out of specification in the evaluation results of UL-94 in Table 1 above means that it falls outside the combustible side.

Example 6
A resin composition was obtained in the same manner as in Example 4 except that 150 parts by weight of the surface-treated gibbsite type aluminum hydroxide particles in Example 3 were used. The evaluation results are shown in Table 2.

Comparative Example 6
A resin composition was obtained in the same manner as in Example 4 except that 150 parts by weight of the surface-treated gibbsite type aluminum hydroxide particles of Comparative Example 2 were used. The evaluation results are shown in Table 2.

注：上記第２表のＵＬ−９４の評価結果における規格外とは、可燃性側に外れることを意味する。 Table 2

Note: Out of specification in the evaluation results of UL-94 in Table 2 above means that it falls outside the combustible side.

Claims (1)

Surface-treated gibbsite type aluminum hydroxide particles in which the surface of gibbsite type aluminum hydroxide particles has been surface-treated with silicone oil,
The gibbsite type aluminum hydroxide particles have an average primary particle size of 0.01 to 0.3 μm, a DOP oil supply amount of 90 to 300 mL / 100 g, and an average secondary particle size of 0.1 to 10 μm. ,
Surface-treated gibbsite-type aluminum hydroxide particles, wherein the silicone oil is used in an amount of 0.5 to 4 parts by weight in the surface-treated gibbsite-type aluminum hydroxide.