JPH01215835A - Flame retardant for resin - Google Patents

Abstract

PURPOSE:To obtain a flame retardant improved in weather resistance and retaining the flame retardance, processability and physical properties of Mg(OH)2, by dispersing a fluoride of Mg of Ca in Mg(OH)2. CONSTITUTION:A soluble salt of Mg of Ca (e.g., CaCl2) and 1-2 equivalents, per equivalent of the desired fluoride, of hydrofluoric acid are added to an aqueous slurry containing 50-200g/l of Mg(OH)2 of a BET specific surface area <=20m<2>/g and a diameter in the direction of the major diameter of 0.3-3mum, and the mixture is agitated at room temperature for 30min to obtain a slurry consisting of 95wt.% Mg(OH)2 in which 0.1-5wt.% Mg or Ca fluoride is dispersed. This slurry is optionally heated to 50-100 deg.C, and 0.1-10%, based on the solid content, metal salt of a fatty acid (e.g., sodium stearate) is added to the slurry to perform its surface treatment, and the product is filtered, washed with water and dried.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a flame retardant for resins, and particularly to a flame retardant for resins that has excellent weather resistance in high temperature and high humidity atmosphere.

[Conventional technology] Flame retardant techniques for resins include adding flame retardants such as aluminum hydroxide, halogen compounds, phosphorus compounds, boron compounds, and antimony compounds, and making the structure of the resin itself flame retardant. Methods have been proposed and implemented. However, since the 1984 underground telephone cable fire accident, there has been a strong demand for flame retardant technology that does not generate harmful gases or even smoke.

Along with this, many inorganic compounds mainly containing aluminum hydroxide are being used. Aluminum hydroxide is thought to make resin flame retardant by absorbing heat during decomposition, but
There is a problem that the flame retardant effect is small because the decomposition temperature is lower than the combustion temperature of the resin. On the other hand, magnesium hydroxide has a decomposition temperature close to the combustion temperature of the resin, and has a large flame retardant effect. It has been attracting attention because it is superior in all respects, as it does not emit toxic gas or smoke.

The following have been proposed as magnesium hydroxide for flame retardants.

For example, in Japanese Patent No. 1374030, magnesium hydroxide, which has excellent flame retardancy and does not significantly impair the properties of the resin, is used as a flame retardant, and has a BET specific surface area of 20 m2/g or less, and a BET specific surface area / Bray ratio specific surface area. 1-3
We are proposing something within this range. Also, for example,
2-ILL (No. 90) uses magnesia in water in a slurry containing magnesium hydroxide seed particles and magnesium salt as a method for obtaining magnesium hydroxide as a flame retardant that has good dispersion in the resin and a low embrittlement temperature of the kneaded resin. He also proposed a method of harmonizing the
In No. +5, in order to prevent the resin containing magnesium hydroxide from forming a white powder after being left in the air (hereinafter referred to as the powdering phenomenon), magnesium or calcium carbonate or basic acid was added to the magnesium hydroxide in advance. They are proposing flame retardants containing carbonates.

Magnesium hydroxide as described above has excellent flame retardancy, does not emit harmful gas or smoke, and does not significantly impair the processability or physical properties of the resin. Furthermore, patent application No. 62-31731
No. 5 also has the effect of preventing the dusting phenomenon after the resin is left standing. However, flame retardant-containing resins may be used for long periods of time at high temperatures and high humidity, and it is important that they do not cause flaking or deterioration due to flame retardant elution even under such conditions. desired.

[Problems to be Solved by the Invention] In view of these circumstances, the present invention provides a novel flame retardant for magnesium hydroxide-based resin that does not cause the above-mentioned drawbacks even when used under high temperature and high humidity conditions. The purpose is to

[Means for Solving the Problems] The present inventors have devised a method that maintains the flame retardancy, non-toxicity, processability, and physical properties of conventional magnesium hydroxide when used as a flame retardant, and also reduces the dusting phenomenon and As a result of continued efforts to obtain a flame retardant for resins that does not easily deteriorate due to dissolution,
The present invention was completed by obtaining completely new knowledge regarding the flame retardant. That is, the structure of the present invention is a flame retardant for resins containing a fluorine compound of magnesium or calcium dispersed in magnesium hydroxide. Here, the fluorine compound of magnesium or calcium means a fluoride of magnesium or calcium, an oxyfluoride, a hydrogen fluoride adsorbent, or the like.

The fluorine compound of magnesium or calcium may contain at least one of them. However, those particles must be dispersed in the magnesium hydroxide. In addition, the amount thereof is preferably 0.1 to 5% by weight, more preferably 0.1 to 3% by weight from the viewpoint of preventing deterioration due to dusting and dissolution and maintaining flame retardancy, processability, and physical properties. Weight%.

To produce the flame retardant for resins, a fluorine compound of magnesium or calcium is wet mixed with magnesium hydroxide, or a magnesium hydroxide slurry or a soluble form of magnesium or calcium such as magnesium chloride or calcium chloride is added to the slurry. A method of adding hydrofluoric acid to a slurry containing salt (hereinafter referred to as a fluorination method) is adopted.

In the case of the fluorination method, the magnesium hydroxide slurry concentration is preferably about 50 to 200 g/Q in consideration of stirring efficiency, economical efficiency, fluorination efficiency, etc. The amount of hydrofluoric acid used is preferably 1 to 2 times the equivalent of the desired fluoride.In the presence of magnesium or calcium ions, fluorination can be carried out at room temperature for about 30 minutes; 50℃ if not present
It is preferable to carry out the heating at a higher temperature.

Magnesium hydroxide, which is a raw material for the flame retardant for resins proposed in the present invention, can be produced by any method such as neutralization of magnesium salt, neutralization of magnesium salt followed by pressure treatment, or hydration of magnesium. However, since the particles and dispersibility of magnesium hydroxide ultimately greatly affect the flame retardancy, processability, and physical properties of the resin, the BET specific surface area is 20 m'7 g or less and the diameter in the major axis direction is 0. It is preferable to use magnesium hydroxide with excellent dispersibility of 3 to 3 μm. More preferably, it is appropriate to use magnesium hydroxide with good dispersibility, which has a BET specific surface area of 10 m2/g or less and a diameter in the major axis direction of 0.5 to 2.5 μm. Alternatively, a material that has been surface-treated as described below may be used.

The content of magnesium hydroxide in the flame retardant for resins of the present invention is preferably 92% by weight or more from the viewpoint of maintaining flame retardancy, processability, and physical properties.

The resin flame retardant of the present invention is preferably used after being surface-treated with a fatty acid metal salt in order to maintain the flame retardancy, processability, and physical properties of the resin. As the fatty acid metal salt, for example, sodium stearate, sodium oleate, etc. can be used. Surface treatment is, for example, 50 to 100
Add fatty acid metal salts under stirring to a 50-200 g/M water slurry heated to
This can be done by adding %.

The flame retardant for resins of the present invention can be widely added to general resins,
These resins can be made flame retardant. These resins may be thermoplastic resins, thermosetting resins, or rubber-like resins.

[Examples] Hereinafter, the present invention will be specifically explained using Examples and Comparative Examples.

Example 1 100g/51 of hexagonal plate-shaped magnesium hydroxide with a specific surface area of 6.6m27g and a diameter in the major axis direction of about 2μm, and 0.51g of magnesium chloride. 39 g of a 5% aqueous hydrofluoric acid solution was added to 15 portions of a water slurry containing 3 mol/Q of OL at room temperature, and the mixture was stirred for 30 minutes. This slurry was surface treated with 10% sodium oleate eoog at 80° C. for 1 hour. This slurry was filtered using two incense burner papers, and then washed with about 5 times the amount of pure water.

The filter cake was heated to 120°C in an ordinary box-type electric dryer for 12 minutes.
Dry for an hour.

11 g of this dry cake, 77 g of ethylene vinyl acetate resin, and 10 g of polyethylene resin containing 40% carbon were kneaded in a kneader at 140 DEG C. for 1 DEG while being vacuum degassed. This kneaded material is 150mm x 100
160℃, 40k in n+m x 2+n+n mold
A sheet was obtained by pressure molding at g/cm 2 .

Using pieces cut out from this sheet, a low temperature brittleness test was conducted in accordance with JIS6301, and a tensile test was conducted in accordance with JIS 7133. The results are shown in Table 1.

Further, as a measure of the torque during kneading, Table 1 shows the difference (A) between the current value when the kneader was running idle and the current value after 10 minutes of kneading. In addition, the Mg (011)2 content in the dry cake is 9
7%, and the fluorine compound content was 0.17%.

In order to investigate the weather resistance of the flame retardant in the resin, a rectangular sample of 2.5c+nX 4cm was cut from the molded sheet and subjected to the carbonation test and dissolution test described below. The carbonation test was conducted as follows. The sample was suspended in a desiccator in a 70° C. saturated steam atmosphere, and carbon dioxide gas was passed through water at 90° C. and left there for about 1 day. The sample after being left was taken out, and the degree of dusting (whitening) on the resin surface was visually evaluated, and the weight increase of the sample compared to before the test was examined. The dissolution test was conducted as follows.

The sample was immersed in a Petri dish filled with tap water at room temperature, and the Petri dish was further placed in a desiccator and left for 4 days while blowing carbon dioxide gas into the desiccator. The weight change (weight loss) of the sample before and after this was investigated. The results are shown in Table 1.

Example 2 98 g of the 5% aqueous hydrofluoric acid solution used in Example 1 was subjected to the same fluorination treatment and surface treatment with sodium oleate. Furthermore, similar resin kneading and molding were performed and evaluated. The results are shown in Table 1.

Example 3 193g of 5% hydrofluoric acid aqueous solution used in Example 1
Then, similar fluorination treatment and surface treatment with sodium oleate were performed. Furthermore, similar resin kneading and molding were performed and evaluated. The results are shown in Table 1.

Example 4 5 g of magnesium chloride hexahydrate LO dissolved in a small amount of water was added to the magnesium hydroxide slurry 1551 of Example 1 at room temperature, stirred for 30 minutes, and then 578 g of a 5% aqueous hydrofluoric acid solution was added and stirred for 30 minutes. Stirred. This slurry was subjected to the same surface treatment as in Example 1, and then subjected to the same resin mixing and molding for evaluation. The results are shown in Table 1.

Example 5 15 g of reagent special grade magnesium fluoride was added to the magnesium hydroxide slurry 159 of Example 1 at room temperature and stirred for 30 minutes. Furthermore, after performing the same surface treatment with sodium oleate as in Example 1, the same resin kneading and molding were performed and evaluated.

The results are shown in Table 1.

Example 6 Magnesium hydroxide from Example 1 was added to slurry 15 at room temperature by dissolving 4.3 g of anhydrous calcium chloride in a small amount of water, and after stirring for 30 minutes, 5% aqueous hydrofluoric acid solution 3 was added.
1 g was added and stirred for 30 minutes. This slurry was subjected to the same surface treatment as in Example 1, and then subjected to the same resin kneading molding and evaluation. The results are shown in Table 1.

Example 7 The same operation as in Example 6 was carried out except that the amount of calcium chloride was 11 g and the 5% aqueous hydrofluoric acid solution was 77 g. The results are shown in Table 1.

Example 8 The same operation as in Example 6 was carried out except that the amount of calcium chloride was 21 g and the 5% aqueous hydrofluoric acid solution was 154 g. The results are shown in Table 1.

Example 9 The same operation as in Example 6 was carried out except that the amount of calcium chloride was 43 g and the 5% aqueous hydrofluoric acid solution was 308 g. The results are shown in Table 1.

Example 10 The same operation as in Example 6 was carried out except that the amount of calcium chloride was 85 g and the 5% aqueous hydrofluoric acid solution was 615 g. The results are shown in Table 1.

Comparative Example 1 Magnesium hydroxide slurry 1551 of Example 1 was subjected to the same surface treatment with sodium oleate as in Example 1 and evaluated. The results are shown in Table 1.

In Examples 1 to 10, the flame retardancy of the flame retardant composite resin was comparable to that of Comparative Example 1, and there were no problems.

[Effects of the Invention] As explained above, the flame retardant of the present invention maintains the flame retardancy, processability, and physical properties inherent to magnesium hydroxide, and is a flame retardant for resins that has excellent weather resistance. It is.

Patent applicant Shin Nippon Chemical Industry Co., Ltd. Agent Patent Attorney Hidetake Komatsu Agent Patent Attorney Hiroshi Asahi

Claims (1)

[Claims] A flame retardant for resins containing a fluorine compound of magnesium or calcium dispersed in magnesium hydroxide.