JP2002348574A - Flame-retarding agent, method for producing the same and flame-retardant resin composition containing the agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flame-retarding agent composed of magnesium hydroxide particle containing zinc as solid solution and giving a flame-retardant resin exhibiting excellent flame-retardance and having excellent transparency and provide a method for the production of the agent and a flame-retardant resin composition containing the agent. SOLUTION: The flame-retarding agent is composed of magnesium hydroxide particle containing zinc in the form of a solid solution in an amount of 0.5-30 mol% based on magnesium and having an average particle diameter of 0.01-1.0 μm and a refractive index of 1.49-1.54. Another flame-retarding agent provided by the invention is composed of magnesium hydroxide particle containing zinc in the form of a solid solution in an amount of 0.5-30 mol% based on magnesium, having an average particle diameter of 0.01-1.0 μm and a refractive index of 1.49-1.54 and having a coating layer composed of a zinc compound and a boron compound on the surface of the particle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame retardant containing magnesium hydroxide particles as a main component, and more particularly, to a flame retardant resin composition having a predetermined average particle size and a refractive index and having excellent transparency. The present invention relates to a flame-retardant comprising zinc-solid-dissolved magnesium hydroxide particles, which gives, a method for producing the same and a flame-retardant resin composition obtained by blending the same with a resin.

[0002]

2. Description of the Related Art Conventionally, thermoplastic resins have excellent moldability and mechanical and electrical properties. Therefore, halogen-based flame retardants such as tetrabromobisphenol A and decabromodiphenyl oxide have been used. The compounded flame-retardant resin composition is widely used in various industrial fields such as, for example, construction, electricity, machinery, and transportation.

[0003] In particular, polyvinyl chloride resin compositions containing a halogen-based flame retardant have excellent flame retardancy.
It is widely used as a molded material such as various building materials including floor materials, and as a covering material for electric wires and cables. However, such molded articles and coating materials, once burned, may cause serious environmental problems due to the generation of toxic gases.

In recent years, in order to solve such a problem, it has been recommended to use a non-halogen resin, particularly a polyolefin resin, as a resin, and to use magnesium hydroxide as a flame retardant.

[0005] It has been well known that metal hydroxides such as magnesium hydroxide are useful as flame retardants. However, in general, the metal hydroxide must be blended in a large amount with respect to the resin in order to impart effective flame retardancy to the resin composition, while the metal hydroxide is a hydrophilic compound having a hydroxyl group. There is a problem that the dispersibility and compatibility with a resin which is an inorganic substance and an organic polymer substance are low, and the dispersibility is poor. In addition, when a large amount of metal hydroxide is added to a resin to form a flame-retardant resin composition, the inherent desirable physical properties of the resin may be impaired. Further, in general, metal hydroxides are basically alkaline substances, and thus easily react with acids. For example, a resin composition containing a large amount of magnesium hydroxide may become watery in the air over time. And the action of carbon dioxide produces carbonates and basic carbonates,
There is a problem of causing a whitening phenomenon in which the surface of the resin composition becomes white.

In order to solve the above-mentioned problems of the flame retardant mainly composed of magnesium hydroxide, various improvements have been conventionally proposed. For example, Japanese Patent Application Laid-Open No. 1-25033
No. 9 proposes to provide a coating layer comprising a higher fatty acid alkali metal salt and a water-insoluble salt of boric acid or silicic acid on the surface of magnesium hydroxide particles. Japanese Patent Application Laid-Open No. 10-338818 proposes providing a coating layer made of aluminum hydroxide on the surface of magnesium hydroxide particles.

Further, as another method, see, for example,
JP-A-144919 proposes a flame retardant comprising magnesium hydroxide particles obtained by dissolving divalent metal ions such as nickel and zinc in magnesium hydroxide.

As described above, conventionally, a coating layer is formed on the surface of magnesium hydroxide particles, or dissimilar metal ions are dissolved in the magnesium hydroxide particles to improve the performance as a flame retardant. Various attempts have been made to improve the properties of the compounded resin composition. However, even if a large amount is added to the resin, the flame retardancy of the obtained resin composition is not sufficient.

Furthermore, when any of the above-mentioned flame retardants, which are mainly composed of conventionally known magnesium hydroxide particles, are blended with a resin, for example, to obtain a resin composition,
The resin composition is cloudy and almost opaque. Therefore, such a resin composition cannot be used as a surface layer on a designed substrate, for example, because of its opacity.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems in a conventional flame retardant mainly composed of magnesium hydroxide, and not only has excellent flame retardancy but also has excellent flame retardancy. It is an object of the present invention to provide a flame retardant comprising zinc-solid-dissolved magnesium hydroxide particles giving a flame-retardant resin composition having high transparency, a method for producing the same, and a flame-retardant resin composition containing the same.

[0011]

According to the present invention, zinc is dissolved in magnesium in the range of 0.5 to 30 mol% with respect to magnesium, and the average particle size is in the range of 0.01 to 1.0 μm. And a first flame retardant comprising zinc-solid-dissolved magnesium hydroxide particles having a refractive index in the range of 1.49 to 1.54.

Further, according to the present invention, as a flame retardant having more excellent flame retardancy, 0.1 to magnesium is preferred.
A solid solution of zinc in the range of 5 to 30 mol%,
Having an average particle size in the range of ~ 1.0 [mu] m and 1.4.
A second solid-state magnesium hydroxide particle having a refractive index in the range of 9 to 1.54 and having on its surface a coating layer of a zinc compound and a boron compound;
Is provided.

According to the present invention, a water-soluble magnesium salt and a water-soluble zinc salt are neutralized with an alkali in the presence of water to form a coprecipitate. A first step of performing a hydrothermal reaction at a temperature of 250 ° C. or less to obtain zinc-dissolved magnesium hydroxide particles, an aqueous suspension of the zinc-dissolved magnesium hydroxide particles, and an aqueous solution of a water-soluble zinc salt. And a water-soluble boron compound aqueous solution to form a coating layer comprising a zinc compound and a boron compound on the surface of the zinc solid solution magnesium hydroxide particles. 2. A method for producing a flame retardant is provided.

Further, according to the present invention, there is provided a flame-retardant resin composition comprising 5-350 parts by weight of the above-mentioned flame retardant per 100 parts by weight of the resin.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The first flame retardant according to the present invention has a solid solution of zinc in the range of 0.5 to 30 mol% with respect to magnesium, and has an average of 0.01 to 1.0 μm. It consists of zinc-solid-dissolved magnesium hydroxide particles having a particle size and a refractive index in the range of 1.49 to 1.54.

In the present invention, the refractive index of the flame retardant is determined by a liquid immersion method. In this method, liquids having different refractive indices are mixed in various ways to prepare mixed liquids having various refractive indices, a sample is immersed in such a mixed liquid, and light is irradiated from the side to obtain a mixed liquid. Is a method in which the refractive index of the mixed liquid when the sample becomes transparent is used as the refractive index of the sample.

The flame retardant comprising such zinc-solid-dissolved magnesium hydroxide particles is obtained by neutralizing a water-soluble magnesium salt and a water-soluble zinc salt with an alkali in the presence of water to obtain a coprecipitate. It can be obtained by hydrothermal reaction of a water slurry (water suspension) containing a precipitate.

Preferably, the first flame retardant according to the present invention comprises, together with an aqueous solution containing a water-soluble magnesium salt and a water-soluble zinc salt in an amount of 0.5 to 30 mol% in terms of zinc with respect to the magnesium, together with the magnesium And an aqueous solution of an alkali, which is approximately equivalent to zinc, is simultaneously added to an appropriate container to simultaneously neutralize the magnesium salt and the zinc salt to form a coprecipitate, and then contain the coprecipitate. The slurry is brought to a temperature above 100 ° C. and below 250 ° C., preferably
Hydrothermal reaction at a temperature in the range of 150 to 200 ° C., filtration,
It can be obtained by washing with water, drying and grinding. The alkali is not particularly limited, but for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is preferably used. If necessary, after the hydrothermal reaction, the obtained reaction mixture may be sieved to remove coarse particles.

In the zinc solid solution magnesium hydroxide particles according to the present invention, the amount of solid solution of zinc is in the range of 0.5 to 30 mol% with respect to magnesium, preferably 1 to 30 mol%.
-10 mol%, and the average particle size is from 0.01 to
It is in the range of 1.0 μm, preferably 0.02 to 0.1 μm.
It is in the range of 5 μm and the refractive index is in the range of 1.49 to 1.54, preferably in the range of 1.50 to 1.53. In particular, according to the present invention, while having a refractive index in the above range, the average particle diameter is in the range of 0.01 to 0.1 μm, and particularly, the average particle diameter is in the range of 0.02 μm to less than 0.1 μm (ie, When the average particle diameter is d (μm),
0.02 ≦ d <0.1) The flame retardant comprising the zinc-solid-dissolved magnesium hydroxide particles is blended with the resin to form a flame-retardant resin composition. Thus, a flame-retardant resin composition having improved tensile strength can be obtained.

According to the present invention, a solid solution of zinc in magnesium hydroxide reduces the refractive index (1.56) of the magnesium hydroxide, thereby reducing the refractive index (1.56) of the magnesium hydroxide in the range of 1.49 to 1.54, preferably The flame retardant according to the present invention having a range of 1.50 to 1.53 can be obtained. However, when the amount of solid solution of zinc in magnesium hydroxide is less than 0.5 mol%, the refractive index of magnesium hydroxide cannot be reduced to 1.54 or less. Even if the particles are mixed with the resin, a resin composition having high transparency cannot be obtained. On the other hand, when the solid solution amount of zinc is 3
When it exceeds 0 mol%, magnesium hydroxide is originally
The desired flame retardancy is impaired, and the resulting zinc-dissolved magnesium hydroxide particles have poor dispersibility in resin.

Further, according to the present invention, the BET specific surface area of the zinc solid solution magnesium hydroxide particles is 1 to 50 m ² / g.
And particularly preferably 3 to 40 m ² / g.
Is preferably within the range.

In the production of the first flame retardant, for example, magnesium chloride or magnesium nitrate is used as a water-soluble magnesium salt, which is one of the raw materials, but is not limited thereto. As the water-soluble zinc salt as the other raw material, for example, zinc chloride or zinc nitrate is used, but is not limited thereto.

The second flame retardant according to the present invention is formed by dissolving zinc in the range of 0.5 to 30 mol% with respect to the above-mentioned zinc-solid-dissolved magnesium hydroxide particles, that is, magnesium. A coating layer composed of a zinc compound and a boron compound on the surface of zinc-solid-dissolved magnesium hydroxide particles having an average particle size in the range of 1.0 to 1.0 μm and a refractive index in the range of 1.49 to 1.54; .

As described above, the zinc-dissolved magnesium hydroxide particles having a coating layer of a zinc compound and a boron compound on the surface thereof were prepared as described above. Thereafter, the slurry of the zinc-dissolved magnesium hydroxide particles, the aqueous solution of the water-soluble zinc salt and the aqueous solution of the water-soluble boron compound are mixed, and the surface of the zinc-dissolved magnesium hydroxide particles is mixed with the zinc compound and the boron compound. It can be obtained by forming a coating layer.

In the present invention, the coating layer on the surface of the zinc-dissolved magnesium hydroxide particles may cover the whole of the zinc-dissolved magnesium hydroxide particles, or may cover only a part thereof. . The zinc compound forming the coating layer is zinc hydroxide, while the boron compound is
It is at least one selected from boric acid, magnesium borate and zinc borate. However, in the present invention, part of the zinc derived from the zinc hydroxide may be dissolved in the magnesium hydroxide particles. Also,
Boron may also be partially dissolved in the magnesium hydroxide particles.

In order to form a coating layer composed of a zinc compound and a boron compound on the surface of the zinc solid solution magnesium hydroxide particles, for example, the zinc solid solution magnesium hydroxide particles are suspended in water to form a water slurry. Aqueous zinc salt aqueous solution is added to the mixture, and the mixture is agitated and aged to precipitate and deposit zinc hydroxide on the surface of the zinc solid solution magnesium hydroxide particles. An aqueous solution of a water-soluble boron compound is added to the slurry, and the mixture is agitated and then aged to precipitate and deposit the boron compound on the surface of the zinc-solid-dissolved magnesium hydroxide particles.

In such a method, an aqueous solution of a water-soluble zinc salt or an aqueous solution of a water-soluble boron compound is added to a slurry of magnesium hydroxide particles in which zinc is dissolved, and the surface of the magnesium hydroxide particles is mixed with a zinc compound and a boron compound. The temperature at which the coating layer is formed may range from 0 to 100 ° C. and may exceed 100 ° C.
When a temperature of 0 ° C. or lower is employed, preferably, 20 to
It is in the range of 95 ° C. On the other hand, when a temperature exceeding 100 ° C. is employed, an aqueous solution of a water-soluble zinc salt and an aqueous solution of a water-soluble boron compound are charged together with a slurry of magnesium hydroxide particles in an autoclave, and the pressure is preferably reduced to 100 ° C. For a suitable time at a temperature from the excess temperature to 200 ° C., for example, but not limited to,
Hydrothermal treatment may be performed with stirring for about 2 hours.

According to such a hydrothermal treatment, a coating layer composed of a zinc compound and a boron compound is formed on the surface of the magnesium hydroxide particles in which zinc is dissolved, and a part of zinc and / or boron is removed from the magnesium hydroxide particles. A solid solution with magnesium can be formed therein.

According to the present invention, the water-soluble zinc salt is used in an amount of 0.01 to 5 mol in terms of zinc in terms of zinc so that the second flame retardant has excellent flame retardancy. %, And the water-soluble boron compound is
0.01 to 1 in terms of boron with respect to magnesium
It is used in the range of 5 mol%. Furthermore, according to the present invention,
Preferably, the water-soluble zinc salt and the water-soluble boron compound are used such that the boron / zinc molar ratio is in the range of 0.001 to 500, and particularly preferably, the boron / zinc molar ratio is 0.01 to 500. Used to be in the range of 50.

In the present invention, examples of the water-soluble zinc salt include, but are not limited to, zinc chloride and zinc nitrate. Further, as the water-soluble boron compound, for example, boric acid, sodium borate, or the like is used, but is not limited thereto.

According to the present invention, the order of adding the aqueous solution of the water-soluble zinc salt and the aqueous solution of the water-soluble boron compound to the slurry of the zinc-solid-dissolved magnesium hydroxide particles is not particularly limited. First, an aqueous solution of a water-soluble boron compound may be added to the slurry of zinc-solid-dissolved magnesium hydroxide particles, or an aqueous solution of a water-soluble zinc salt and an aqueous solution of a water-soluble boron compound may be added simultaneously.

After forming a coating layer comprising a zinc compound and a boron compound on the surface of the zinc-solid-dissolved magnesium hydroxide particles in the slurry in this manner, the slurry is filtered, washed with water and dried to obtain the slurry according to the present invention. A second flame retardant can be obtained.

The second embodiment of the present invention thus obtained
Has a coating layer composed of a zinc compound and a boron compound on the surface of zinc-solid-dissolved magnesium hydroxide particles, and the zinc compound is in a range of 0.01 to 5 mol% in terms of zinc with respect to magnesium. And the boron compound is in the range of 0.001 to 15 mol% with respect to magnesium in terms of boron. In particular, in the second flame retardant according to the invention, preferably the molar ratio of boron / zinc in the coating layer is in the range from 0.001 to 10.

By blending the second flame retardant according to the present invention with a resin, it is possible to obtain a flame-retardant resin composition having not only excellent transparency but also significantly improved flame retardancy. .

In particular, according to the present invention, as described above,
The average particle size is from 0.01 to 0.1 μm, especially, those having an average particle size of less than 0.02 μm to 0.1 μm are blended with a resin to form a flame-retardant resin composition. A flame-retardant resin composition having not only high transparency but also improved tensile strength can be obtained.

Each of the first and second flame retardants according to the present invention may be further treated with a surface treating agent. Examples of the surface treatment agent include a silane coupling agent and a higher fatty acid.

For the surface treatment of the first flame retardant, for example, as described above, a water-soluble magnesium salt and a water-soluble zinc salt are neutralized with an alkali to form a coprecipitate. Is subjected to a hydrothermal reaction to generate magnesium hydroxide particles in which zinc is dissolved, and then a higher fatty acid or a silane coupling agent is directly added to the slurry containing magnesium particles in which zinc is dissolved, followed by heating and stirring. Then, surface treatment is performed, and then filtration, washing with water, and drying may be performed.

In order to surface-treat the second flame retardant,
For example, as described above, zinc solid solution magnesium hydroxide particles are suspended in water to form a slurry, and zinc hydroxide and a boron compound are sequentially deposited and deposited on the zinc solid solution magnesium hydroxide particles, As described above, a higher fatty acid or a silane coupling agent is directly added to the slurry of the zinc solid solution magnesium hydroxide particles having the coating layer composed of the zinc compound and the boron compound, and heated and stirred to perform a surface treatment. What is necessary is just to filter, wash and dry.

The silane coupling agent is not particularly limited, but includes, for example, vinylethoxysilane, vinyltris (2-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane,
γ-aminopropyltrimethoxysilane, β- (3,4
-Epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ
-Mercaptopropyltrimethoxysilane and the like. Such a silane coupling agent is generally used in the range of 0.1 to 10% by weight, preferably 0.3 to 7% by weight, based on the magnesium hydroxide particles.

However, according to the present invention, if necessary,
In addition to silane coupling agents, titanate-based coupling agents and aluminum-based coupling agents can also be used.

The fatty acid is preferably, for example, a saturated or unsaturated higher fatty acid having 14 to 24 carbon atoms, and specific examples thereof include, for example, oleic acid and stearic acid. Such fatty acids are
Usually, 0.5-5.
0% by weight, preferably in the range of 1.0 to 3.0% by weight.

The surface-treated flame retardant is excellent in dispersibility in a resin, and by blending such a flame retardant with the resin, mechanical properties such as flame retardancy excellent in tensile strength can be obtained. A resin composition can be obtained.

The flame-retardant resin composition according to the present invention can be obtained by uniformly mixing the above-mentioned flame retardant with the resin. The mixing ratio of the flame retardant to the resin depends on the use and required characteristics of the resin composition to be obtained, but usually, the present invention is prepared by mixing 5-350 parts by weight of the flame retardant with respect to 100 parts by weight of the resin. To obtain a flame-retardant resin composition.

For example, in order to obtain a flame-retardant resin composition for use in general molded articles such as building materials such as flooring materials, wallpaper and decorative boards, casings of electric equipment and transparent films, resin 100 is used.
A resin composition comprising 5 to 100 parts by weight of the flame retardant according to the present invention with respect to parts by weight is preferably used. On the other hand, in order to form a self-extinguishing resin composition such as an electric wire or cable coating, usually 100 to 350 parts by weight of the flame retardant according to the present invention, preferably 1 to 100 parts by weight of the resin.
A resin composition containing 50 to 300 parts by weight is preferably used. When the compounding amount of the flame retardant exceeds 100 parts by weight of the resin, the mechanical properties of the resin may be deteriorated.

In the present invention, the above resin may be appropriately selected according to the application and required characteristics. Specific examples include polyethylene, polypropylene, ethylene-propylene copolymer, and ethylene-propylene-diene monomer ternary copolymer. Polymer, ethylene-butene copolymer, ethylene-
Polyolefin resins which are homo- or copolymers of olefins such as acrylate (eg, ethyl acrylate) copolymer, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, and aromatics such as styrene Homopolymer of vinyl monomer, copolymer such as ABS resin, poly (meth) acrylic resin, polyester such as polyethylene terephthalate, polybutylene terephthalate, polyarylate, 6-nylon, 6,6-nylon, 12- Nylon, 46-nylon, polyamide such as aromatic polyamide, polyphenylene ether, modified polyphenylene ether, polyether such as polyoxymethylene, polycarbonate, styrene-conjugated diene copolymer, polybutadiene, polyisoprene, acrylonitrile-butadiene Copolymer elastomer polychloroprene, and polyvinyl chloride.
If necessary, a thermosetting resin such as a phenol resin, an epoxy resin, an unsaturated polyester, or a polyurethane may be used as the resin. These resins are used alone or as a mixture of two or more.

In particular, according to the present invention, a resin having a refractive index in the range of 1.48 to 1.52 is preferably used. As such a resin, for example, polyethylene,
Polypropylene, various ethylene-acrylate copolymer resins including ethylene-ethyl acrylate copolymer, polystyrene, AS resin, ABS resin, polymethyl methacrylate, polyvinyl acetate and other resins, SBR, natural rubber, polybutadiene rubber And rubbers such as polyisoprene rubber. Among them, particularly, polyethylene, polypropylene, ethylene-acrylate copolymer and the like are preferably used.

According to the present invention, by blending the flame retardant according to the present invention with a resin having a refractive index in the range of 1.48 to 1.52, a resin composition having particularly high transparency can be obtained. You can get things.

The flame-retardant resin composition according to the present invention may optionally contain other additives according to the respective resins, in addition to the above-mentioned flame retardants. As such additives, for example, plasticizers, lubricants, fillers, antioxidants, heat stabilizers, nucleating agents, crosslinking agents, crosslinking aids, antistatic agents, compatibilizers, light stabilizers, pigments, Foaming agents, fungicides and the like can be mentioned. Also, if necessary,
Other conventionally known flame retardants and flame retardant auxiliaries may be added.

Such a resin composition is mixed and kneaded with the above-described flame retardant by appropriate means such as a single-screw extruder, a twin-screw extruder, a roll kneader, a kneader kneader, and a Banbury mixer. Can be obtained by: Further, the resin composition according to the present invention thus obtained is, for example, injection molding, extrusion molding, blow molding, press molding, vacuum molding, calendar molding, transfer molding, lamination molding, etc. It can be suitably used for the production of various molded products by appropriate means.

[0050]

The first flame retardant according to the present invention is formed by dissolving zinc in magnesium and forming a solid solution of 0.01 to 1.0 μm.
m in the range of 1.49 to 1.5
It is made of zinc-solid magnesium hydroxide particles having a refractive index in the range of 4, and provides a resin composition having not only excellent flame retardancy but also excellent transparency when incorporated into a resin. The second flame retardant according to the present invention has a coating layer comprising a zinc compound and a boron compound on the surface of the zinc solid solution magnesium hydroxide particles, and when blended with a resin, forms a resin composition having excellent transparency. In addition to the above, a resin composition having remarkably excellent flame retardancy as compared with a conventional flame retardant comprising magnesium hydroxide particles is provided.

Further, by treating such a flame retardant composed of magnesium hydroxide particles with a silane coupling agent or a higher fatty acid, a flame retardant having more excellent dispersibility in a resin can be obtained.

Accordingly, the resin composition containing the flame retardant according to the present invention, particularly the polyolefin resin composition, is excellent not only in flame retardancy but also in transparency, and is, for example, used for flooring, wallpaper, It can be suitably used in the production of building materials such as decorative boards, sheets and films, covering of electric wires and cables, electric parts and automobile parts, and various molded articles such as pipes.

[0053]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited by these examples.

Example 1 (Preparation of Flame Retardant A) 38.4 L of a 4 mol / L magnesium chloride aqueous solution and 1.41 L of a 2.1 mol / L zinc chloride aqueous solution were mixed to prepare a mixed aqueous solution. Separately
21. An aqueous solution of sodium hydroxide having a concentration of 14.3 mol / L
5 L was prepared.

The mixed aqueous solution and the sodium hydroxide aqueous solution were simultaneously poured into a precipitation reactor filled with 11.3 L of pure water in advance, and magnesium chloride and zinc chloride were simultaneously neutralized.
A slurry containing the coprecipitate was obtained. 100 L of this slurry
The resulting mixture was charged into an autoclave having a capacity and subjected to a hydrothermal reaction at a temperature of 170 ° C. for 1 hour to obtain a slurry containing magnesium hydroxide particles in which zinc was dissolved.

With respect to the magnesium hydroxide dissolved in zinc,
0% by weight of γ-methacryloxypropyltrimethoxysilane was added to the slurry and stirred at 70 ° C. for 1 hour.
Thereafter, the zinc solid solution magnesium hydroxide particles treated with the silane coupling agent are filtered from the slurry,
Separated, washed with water, dried and then pulverized to obtain a first flame retardant A according to the present invention comprising surface-treated zinc solid-dissolved magnesium hydroxide particles. The surface-treated zinc solid solution magnesium hydroxide particles had an average particle size of 0.08 μm, a zinc solid solution amount of 2.0 mol% with respect to magnesium, and a refractive index of 1.5.
It was 2.

Example 2 (Preparation of Flame Retardant B) A zinc solid solution was prepared in the same manner as in Example 1 except that 19.3 L of an aqueous solution of sodium hydroxide having a concentration of 14.3 mol / L was used. Magnesium hydroxide particles were obtained and treated with a silane coupling agent in the same manner as in Example 1 to obtain a first flame retardant B according to the present invention. The surface treated zinc solid solution magnesium hydroxide particles had an average particle size of 0.5 μm, a zinc solid solution amount of 2.0 mol% with respect to magnesium, and a refractive index of 1.52.

Example 3 (Preparation of Flame Retardant C) Zinc-dissolved magnesium hydroxide particles were filtered from the slurry containing zinc-dissolved magnesium hydroxide particles obtained in Example 1, washed with water, and the obtained cake was washed. The slurry was redispersed in water to prepare a slurry having a concentration of 130 g / L. This slurry was heated to 90 ° C. and 2.1 mol /
After adding 0.77 L of an L-concentration aqueous zinc chloride solution (1 mol% in terms of zinc with respect to magnesium), the mixture is aged at 70 ° C. for 30 minutes to form a hydroxide on the surface of the zinc-dissolved magnesium hydroxide particles. Zinc was deposited and deposited.

Then, while maintaining the temperature of the slurry at 70 ° C., 1.8 L of a 2.0 mol / L boric acid aqueous solution (3 mol% in terms of boron with respect to magnesium) was added thereto. After aging for 30 minutes at a temperature of 70 ° C., a boron compound was deposited and deposited on the surface of the magnesium hydroxide particles.

Next, the slurry containing the surface-coated zinc-solid-dissolved magnesium hydroxide particles thus obtained was added to the slurry at a temperature of 70%.
Γ-methacryloxypropyltrimethoxysilane was added at 2.0% by weight to magnesium hydroxide at 70 ° C.
For 1 hour. Thereafter, the surface-coated zinc-solid-dissolved magnesium hydroxide particles thus treated with the silane coupling agent are separated from the slurry by filtration, washed with water, dried and pulverized to obtain a flame retardant C according to the present invention. Was.

The zinc content in the coating layer of the surface-coated zinc solid-dissolved magnesium hydroxide particles thus treated is 1 mol%, the boron content is 0.7 mol%, and the average particle diameter is 0.1 mol%.
08 μm and the refractive index was 1.52.

Example 4 (Preparation of flame retardant D) A zinc solid was prepared in the same manner as in Example 3 except that 19.3 L of an aqueous solution of sodium hydroxide having a concentration of 14.3 mol / L was used. Soluble magnesium hydroxide particles were obtained, and in the same manner as in Example 3, the surfaces of the magnesium hydroxide particles were coated with a zinc compound and a boron compound, and then treated with a silane coupling agent to obtain an average particle size of 0.5 μm. A flame retardant D comprising 1 mol% of zinc and 0.7 mol% of boron in the coating layer and comprising surface-treated zinc-solid-dissolved magnesium hydroxide particles having a refractive index of 1.52 was obtained.

Comparative Example 1 (Preparation of Flame Retardant E) Magnesium hydroxide particles having an average particle diameter of 0.8 μm were dispersed in water to form a slurry, which was heated to 90 ° C. After adding 0% by weight of stearic acid and stirring for 1 hour, the mixture was filtered, washed with water, dried and pulverized to obtain a flame retardant E according to a comparative example.

Comparative Example 2 (Preparation of Flame Retardant F) Magnesium hydroxide particles having an average particle diameter of 0.8 μm were dispersed in water to form a slurry, which was heated to 70 ° C. 0% by weight of γ-methacryloxypropyltrimethoxysilane was added, and the mixture was stirred for 1 hour, filtered, washed with water, dried and pulverized to obtain a flame retardant F according to a comparative example.

Example 5 (Preparation of Flame-Retardant Resin Composition and Evaluation of its Transparency) Ethylene-ethyl acrylate copolymer (abbreviated as EEA; ethyl acrylate content: 15% by weight; melt flow rate: 0.1%) 8 g / 10 min, melting point 100 ° C.) and 100 parts by weight of the flame retardants prepared in Examples 1 to 4 and Comparative Examples 1 and 2 were mixed, and the mixture was mixed with a batch-type twin-screw kneader to obtain 1 part.
After melt-kneading at 70 ° C. for 15 minutes, biaxial roll rolling was performed to obtain pellets. The pellets were heated and melted at 180 ° C. and formed into a film having a thickness of 100 μm using a film forming machine, and the haze and total light transmittance of the film were measured.
Table 1 shows the results.

Example 6 (Preparation of Flame-Retardant Resin Composition and Evaluation of Its Transparency) 100 parts by weight of a polypropylene (abbreviated as PP) resin were prepared in the above Examples 1 to 4 and Comparative Examples 1 and 2. Flame retardant 5
0 parts by weight and mixed using a batch-type twin-screw kneader.
After melt-kneading at 0 ° C. for 15 minutes, biaxial roll rolling is performed,
Pellets were used. The pellets are heated and melted at 220 ° C., and formed into a film having a thickness of 100 μm using a film forming machine.
For this, haze and total light transmittance were measured. Table 1 shows the results.

[0067]

[Table 1]

As shown in Table 1, the transparency of the resin composition containing the flame retardant of the present invention is remarkably improved as compared with the conventionally known resin composition containing the flame retardant. ing. In particular, in the case of the flame retardants A and C, the contact clarity, that is, the clarity of characters and the like seen through the resin sheet when the resin sheet is placed on newsprint or the like is remarkable.

Example 7 (Preparation of Flame Retardant Resin Composition and Evaluation of Its Flame Retardancy and Mechanical Properties) The same procedure as in Example 5 was repeated except that 100 parts by weight of the same ethylene-ethyl acrylate copolymer were used. And Comparative Examples 1 and 2
A predetermined amount of the flame retardant prepared in 1) was added, and the mixture was melted and kneaded at 170 ° C. for 15 minutes using a kneader kneader to form pellets. This pellet is heated at 130 ° C with a biaxial roll.
And kneaded for 3 minutes with a hot press at a temperature of 160 ° C. for 3 minutes at a pressure of 50 kgf / cm ² to obtain a thickness of 1/16.
It was formed into an inch film. The film thus obtained was punched out in a strip shape, used as a sample for a flame retardant test based on the UL94VE method, and the minimum blending amount of a flame retardant to pass the UL94V-0 standard was determined.

To 100 parts by weight of the same ethylene-ethyl acrylate copolymer as in Example 5, 200 parts by weight of the flame retardants prepared in Examples 1 to 4 and Comparative Examples 1 and 2 were added, and a kneader kneader was used. After melt-kneading at 170 ° C. for 15 minutes, pellets were formed. The pellets were kneaded with a biaxial roll at 130 ° C. for 3 minutes, and then pressed by a hot press at a temperature of 160 ° C. for 3 minutes at 50 kgf / cm ² to form a film having a thickness of 1.0 mm. This film was punched out with a No. 2 dumbbell to form a test piece, and JIS K
The tensile strength was measured according to 6723. Table 2 shows the results.

[0071]

[Table 2]

As can be seen from Table 2, the resin composition containing the flame retardant of the present invention has higher mechanical properties, especially tensile strength, than the resin composition containing the conventionally known flame retardant. Has been improved.

Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court II (Reference) // C01F 5/14 C01F 5/14 (72) Inventor Kenichi Nakagawa 5-1-1 Ebisshimacho, Sakai City, Osaka Sakai Chemical Industry (72) Inventor Yutaka Ito 5-1-1 Ebishima-cho, Sakai-shi, Osaka Sakai Chemical Industry Co., Ltd. F-term (reference) FB076 FB086 FB096 GQ00

Claims (11)

[Claims] 1. 0.5 to 30 mol% based on magnesium
From a solid-solution magnesium hydroxide particle having a mean particle size in the range of 0.01 to 1.0 μm and a refractive index in the range of 1.49 to 1.54. A flame retardant characterized by becoming. 2. The flame retardant according to claim 1, which is surface-treated with a higher fatty acid and / or a silane coupling agent. 3. 0.5 to 30 mol% based on magnesium
And has a mean particle size in the range of 0.01 to 1.0 μm, a refractive index in the range of 1.49 to 1.54, and a zinc compound on the surface. A flame retardant comprising zinc-solid-dissolved magnesium hydroxide particles having a coating layer comprising a boron compound. 4. The coating layer, wherein the zinc compound is in the range of 0.01 to 5 mol% in terms of zinc with respect to magnesium, and the boron compound is in the range of 0.001 to 15 mol% with respect to magnesium in terms of boron. The flame retardant according to claim 3, wherein 5. The flame retardant according to claim 3, wherein the zinc compound is zinc hydroxide and the boron compound is at least one selected from boric acid, magnesium borate and zinc borate. 6. The flame retardant according to claim 3, which is further surface-treated with a higher fatty acid and / or a silane coupling agent. 7. The method according to claim 7, wherein the magnesium hydroxide particles having a solid solution of zinc have a content of 0.0%.
The flame retardant according to any one of claims 1 to 6, having an average particle size in a range of 1 to 0.1 µm. 8. A flame-retardant resin composition having excellent transparency, comprising 5-350 parts by weight of the flame retardant according to claim 1 with respect to 100 parts by weight of the resin. 9. The resin according to claim 8, wherein the resin is a polyolefin resin.
3. The flame-retardant resin composition according to item 1. 10. A coprecipitate is formed by neutralizing a water-soluble magnesium salt and a water-soluble zinc salt with an alkali in the presence of water to form a coprecipitate. A first step of performing a hydrothermal reaction at the following temperature to obtain zinc-dissolved magnesium hydroxide particles, and a slurry of the zinc-dissolved magnesium hydroxide particles, an aqueous solution of a water-soluble zinc salt, and an aqueous solution of a water-soluble boron compound. And a second step of forming a coating layer comprising a zinc compound and a boron compound on the surface of the zinc-solid-dissolved magnesium hydroxide particles. A method for producing the flame retardant according to the above. 11. In the second step, a water-soluble zinc salt is used in an amount of 0.01 to 5 mol% in terms of zinc with respect to magnesium, and a water-soluble boron compound is used in terms of boron with respect to magnesium. The method for producing a flame retardant according to claim 10, which is used in a range of 0.01 to 15 mol%.