JP4366364B2 - Flame retardant, flame retardant resin composition and molded article - Google Patents

Description

  The present invention relates to a magnesium hydroxide-based flame retardant, a flame retardant resin composition containing the flame retardant, and a molded article thereof.

Conventionally, flame retardants using organic halides (mainly bromides) and antimony trioxide flame retardant aids have been widely used for the purpose of flame retardant resin compositions such as plastic products and synthetic fibers. . However, although such a flame retardant has an excellent flame retardant effect, it decomposes during the molding process and generates halogen gas, which corrodes the molding machine and adversely affects the performance of the molded body itself. In addition, since halogen gas is toxic, it also causes health damage to workers who perform molding. Furthermore, such a halogen gas has a large load on the natural environment.
Therefore, various so-called non-halogen flame retardants have been developed, and magnesium hydroxide, which is an inorganic substance, has been widely used as a flame retardant. Since magnesium hydroxide does not contain halogen, it is used mainly for building material applications such as electric wire coating and wallpaper as an alternative to halogen flame retardants. In these applications, it is often added to a polyolefin resin composition in particular (for example, Patent Document 1). In addition, an example is known in which heat resistance during resin processing is improved by reducing iron compounds, manganese compounds, and the like, which are impurities contained in magnesium hydroxide particles (for example, Patent Document 2).

JP-A-1-141929 JP-A-9-227784

  However, the magnesium hydroxide flame retardant disclosed in Patent Document 1 has insufficient flame retardancy, and therefore, it is necessary to mix a considerable amount of silicone oil. On the other hand, if too much silicone oil is mixed, the mechanical strength, heat resistance, and durability of the resin molded product may be adversely affected. In addition, the magnesium hydroxide flame retardant described in Patent Document 2 is intended to improve the heat resistance of the molded body and the resin processing by reducing the amount of heavy metal as an impurity. It does not improve the flame retardant effect of the flame retardant itself. Furthermore, when the flame retardant is poorly dispersed, the appearance of the molded body is also deteriorated. Therefore, a flame retardant having excellent dispersibility in the resin (in the molded body) is also required.

  Therefore, the present invention provides a flame retardant that is excellent in flame retardancy itself, has good dispersibility in a molded article and does not cause poor appearance, a flame retardant resin composition containing the flame retardant, and a molded article. For the purpose.

  As a result of intensive studies on the magnesium hydroxide flame retardant, the present inventor made the structure of the magnesium hydroxide particles themselves specific and iron that was conventionally considered as a simple impurity during the production of magnesium hydroxide. It has been found that the above-mentioned problems can be solved by controlling the compounds and phosphorus compounds within a predetermined range. The present invention has been completed based on such findings.

That is, in the flame retardant of the present invention, (a) the content of iron compound is 100 to 1000 ppm by mass in terms of iron atom, and (b) the content of phosphorus compound is 100 to 1000 in terms of phosphorus atom. It is characterized by being composed of magnesium hydroxide particles having a mass ppm, (c) a specific surface area by BET method of 1 to 15 m ² / g, and (d) an average particle diameter of 0.5 to 2 μm.

According to the flame retardant of the present invention, the content of the iron compound and the phosphorus compound contained in the magnesium hydroxide particles is within a specific range. Therefore, when this flame retardant is blended with a molded body made of a synthetic resin, the molded body has difficulty. Very good flammability. Here, when either compound of iron or phosphorus contained in the magnesium hydroxide particles is less than 100 ppm by mass in terms of iron atoms or phosphorus atoms, the molded body can be formed even if the same amount of magnesium hydroxide particles is blended. The flame retardancy of is insufficient. Conversely, if the iron compound exceeds 1000 ppm by mass in terms of iron atoms, the magnesium hydroxide particles are severely colored, making it difficult to color the molded product. When the phosphorus compound exceeds 1000 mass ppm in terms of phosphorus atom, there is no problem of coloring, but the dispersibility of the magnesium hydroxide particles in the resin deteriorates and the appearance of the molded article deteriorates. Each of these contents is preferably 100 to 600 ppm by mass, and more preferably 100 to 300 ppm by mass.
The reason why the flame retardancy is improved in this way is presumed to be that the iron compound and the phosphorus compound act as a char generation promoting catalyst due to the synergistic effect of each other during combustion. If the blending amount of either one of the iron compound and the phosphorus compound is less than 100 ppm by mass in terms of iron atom or phosphorus atom, it is considered that char generation is insufficient and flame retardancy is deteriorated.

Further, the flame retardant of the present invention has a BET specific surface area of magnesium hydroxide particles of 1 to 15 m ² / g and an average particle diameter of 0.5 to 2 μm, so that it is fundamental as a flame retardant resin composition. Satisfying required characteristics. That is, when the BET specific surface area exceeds 15 m ² / g or the average particle diameter is less than 0.5 μm, reaggregation is likely to occur when the flame retardant is blended into the resin, and in the resin (in the molded body). As a result, the dispersibility of the resin deteriorates, causing the appearance of the molded article to deteriorate, and the tensile elongation is also reduced. Further, when the BET specific surface area is less than 1 m ² / g, there is no problem in the dispersibility of the flame retardant in the resin (in the molded body), but the flame retardancy of the molded body is deteriorated and the tensile strength of the molded body is reduced. The strength also decreases. On the other hand, if the average particle diameter exceeds 2 μm, the dispersibility in the resin (in the molded body) is lowered, resulting in poor appearance of the molded body, and further the tensile strength is lowered.

In this invention, it is preferable that content of the said iron compound and phosphorus compound is 200-1200 mass ppm in conversion of an iron atom and a phosphorus atom.
When the total content of the iron compound and the phosphorus compound is 1200 ppm by mass or less in terms of iron atoms and phosphorus atoms, there is little influence on the coloring of the magnesium hydroxide particles, and the dispersion of the magnesium hydroxide particles in the resin In addition, the appearance of the molded body is further improved. The total content of the iron compound and the phosphorus compound is more preferably 200 to 600 mass ppm in terms of iron atom and phosphorus atom.

In the present invention, the magnesium hydroxide particles are at least one surface treatment selected from higher fatty acids, higher fatty acid metal salts, surfactants, coupling agents, esters composed of polyhydric alcohols, and phosphate esters. It is preferable that the surface is treated with an agent.
According to this invention, since the magnesium hydroxide particles are treated with the predetermined surface treatment agent, the magnesium hydroxide particles are easily dispersed in the resin (in the molded body), and therefore the above-described effects are further exhibited. can do.

  Here, examples of the higher fatty acid include higher fatty acids having 10 or more carbon atoms such as stearic acid, erucic acid, palmitic acid, lauric acid, and behenic acid, and metal salts thereof. The metal salt is preferably an alkali metal salt from the viewpoint of dispersibility.

As the surfactant, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant can be suitably used.
Examples of anionic surfactants include alkyl sulfates such as sodium lauryl sulfate, higher alcohol sodium sulfate, and triethanolamine lauryl sulfate; alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate; alkylnaphthalenes such as sodium alkylnaphthalenesulfonate Sulfonates: Alkylsulfosuccinates such as sodium dialkylsulfosuccinate; Alkyldiphenyl ether disulfonates such as alkyl diphenyl ether disulfonate; Alkyl phosphates such as potassium alkyl phosphate; Sodium polyoxyethylene lauryl ether sulfate , Sodium polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl ether triethanolamine sulfate, polyoxyethylene Ruki Ruch enyl ether polyoxyethylene alkyl (or alkyl aryl), such as sodium sulfate and the like sulfuric ester salts and the like.

  Examples of cationic surfactants and amphoteric surfactants include alkylamine salts such as coconut amine acetate and stearylamine acetate; lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, cetyltrimethylammonium chloride, distearyldimethylammonium chloride, alkyl Quaternary ammonium salts such as pendyldimethylammonium chloride: alkyl betaines such as lauryl betaine, stearyl betaine, lauryl carboxymethyl hydroxyethyl imidazolinium betaine; amine oxides such as lauryl dimethylamine oxide, and the like.

  Nonionic surfactants include polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl ether such as polyoxyethylene higher alcohol ether, polyoxyethylene Polyoxyethylene alkyl aryl ethers such as nonylphenyl ether; polyoxyethylene derivatives; sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, sorbitan sesquioleate Sorbitan fatty acid esters such as sorbitan distearate; polyoxyethylene sorbitan monolaurate, polyoxy Polyoxyethylene sorbitan such as Tylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate Fatty acid esters; Polyoxyethylene sorbitol fatty acid esters such as polyoxyethylene sorbitol tetraoleate; Glycerin fatty acid esters such as glycerol monostearate, glycerol monooleate, and self-emulsifying glycerol monostearate; Polyethylene glycol monolaurate, polyethylene glycol Monostearate, polyethylene glycol distearate, polyethylene glycol Polyoxyethylene fatty acid esters, such as oleate polyoxyethylene alkylamine, polyoxyethylene hardened castor oil, alkyl alkanol amide.

  Examples of the coupling agent include γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropyltriethoxysilane. Γ-acryloxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, p-trimethoxysilylstyrene, p-triethoxysilylstyrene, p-trimethoxysilyl-α-methylstyrene, p-triethoxysilyl -Α-methylstyrene 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxy Sisilane, N-2 (aminoethyl) 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-propyl-3-aminopropyltri Silane coupling agents such as methoxysilane, 4-aminobutyltrimethoxysilane, decyltrimethoxysilane, isopropyltriisostearoyl titanate, isopropyltris (dioctylpyrophosphate) titanate, isopropyltri (N-aminoethyl-aminoethyl) Examples include titanate coupling agents such as titanate and isopropyltridecylbenzenesulfonyl titanate, and aluminum coupling agents such as acetoalkoxyaluminum diisopropylate. . Such coupling agents may be used alone or in combination of two or more.

  Examples of the ester composed of a polyhydric alcohol include esters of polyhydric alcohols such as glycerin monostearate and glycerin monooleate with fatty acids. Examples of the phosphoric acid ester include mono- or diesters such as orthophosphoric acid and oleyl alcohol, stearyl alcohol, or a mixture of both, and their acid forms or phosphate esters such as alkali metal salts or amine salts.

In order to perform surface treatment of magnesium hydroxide particles using such a surface treatment agent, a known wet method or dry method can be applied. For example, as a wet method, a surface treatment agent may be added to a magnesium hydroxide slurry in a solution state or an emulsion state, and mechanically mixed at a temperature of about 100 ° C., for example. As a dry method, the surface treatment agent may be added in a liquid, emulsion, or solid state with stirring using a mixer such as a Henschel mixer and mixed sufficiently with heating or non-heating. The addition amount of the surface treatment agent can be selected as appropriate, but is preferably about 10 parts by mass or less with respect to the magnesium hydroxide particles.
The surface-treated magnesium hydroxide particles are subjected to appropriate selection of means such as water washing, dehydration, granulation, drying, pulverization, and classification as necessary to obtain a final product (flame retardant). be able to.

The flame retardant resin composition of the present invention is characterized by blending the above-mentioned flame retardant with 5 to 500 parts by mass, preferably 20 to 400 parts by mass with respect to 100 parts by mass of the synthetic resin.
Here, as a synthetic resin, what is normally used as a molded object should just be used, and a thermoplastic resin, a thermosetting resin, or a synthetic rubber is mentioned.
Examples of the thermoplastic resin include polyolefin resins such as polymers or copolymers of C2-C8 olefins (α-olefins) such as polyethylene, polypropylene, ethylene-propylene copolymer, polybutene, and poly-4-methylpentene-1. Copolymer of olefin and diene, ethylene-acrylate copolymer, polystyrene, ABS resin, AAS resin, AS resin, MBS resin, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, ethylene- Vinyl chloride-vinyl acetate copolymer, polyvinylidene chloride, polyvinyl chloride, chlorinated polyethylene, chlorinated polypropylene, vinyl chloride-propylene copolymer, polyvinyl acetate, phenoxy resin, polyacetal, polyamide, polyimide, polycarbonate, polysulfone, Polif Two alkylene oxide, polyphenylene sulfide, polyethylene terephthalate, polybutylene terephthalate, and methacrylic resins.
Among these thermoplastic resins, preferred examples include polyolefin resins or copolymers thereof that have a high flame retardant effect due to magnesium hydroxide particles and are excellent in mechanical strength.

  Examples of the thermosetting resin include an epoxy resin, a phenol resin, a melamine resin, an unsaturated polyester resin, an alkyd resin, and a urea resin. Examples of the synthetic rubber include EPDM, butyl rubber, isoprene rubber, SBR, NBR, chlorosulfonated polyethylene, NIR, urethane rubber, butadiene rubber, acrylic rubber, silicone rubber, and fluorine rubber.

When the flame retardant resin composition of the present invention is further blended with a flame retardant aid, the blending ratio of magnesium hydroxide particles can be reduced, and the flame retardant effect can be improved.
As the flame retardant aid, red phosphorus, carbon powder or a mixture thereof is preferable. As red phosphorus, in addition to normal red phosphorus for flame retardants, for example, red phosphorus whose surface is coated with a thermosetting resin, polyolefin, carboxylic acid polymer, titanium oxide or titanium aluminum condensate can be used. Examples of the carbon powder include carbon black, activated carbon, and graphite. This carbon black is prepared by any of the oil furnace method, gas furnace method, channel method, thermal method, or acetylene method. May be.
When mix | blending a flame retardant adjuvant, the range of 0.5-20 mass% with respect to a flame retardant resin composition whole quantity, Preferably the range of 1-15 mass% is suitable.

  As long as the effects of the present invention are not impaired, the flame retardant resin composition of the present invention may contain other additives in addition to the above components. Examples of such additives include antioxidants, antistatic agents, pigments, foaming agents, plasticizers, fillers, reinforcing agents, flame retardants, crosslinking agents, light stabilizers, UV absorbers, and lubricants. It is done.

The molded article of the present invention is characterized by comprising the above-mentioned flame retardant resin composition.
Here, the molded body of the present invention can be obtained by a generally known molding method after blending a predetermined amount of magnesium hydroxide particles with a synthetic resin. For example, extrusion molding, injection molding, calendar molding, and the like.
According to the molded article of the present invention, since the predetermined magnesium hydroxide particles described above are blended, the flame retardancy is excellent and the appearance of the molded article is also excellent. Applications of such molded products include wire coverings, household appliance housings, building material wallpaper, foam insulation, mats, connector connection parts for electrical and electronic parts, semiconductor sealing materials, prepregs , Multilayer circuit boards, circuit board laminates, and the like.

Hereinafter, the present invention will be described in detail based on examples and comparative examples. However, the present invention is not limited to these examples.
[Example 1]
After producing a flame retardant composed of magnesium hydroxide particles, this flame retardant was blended with a predetermined resin to obtain a flame retardant resin composition. Further, this composition was molded into a molded body, and its flame retardancy was evaluated. Specifically, it is as follows.

(Manufacture of flame retardant)
Put 2L of 3.8N-HCl solution in a 3L polyethylene container and add 222g of general-purpose magnesium hydroxide (hereinafter also referred to as "Mg (OH) ₂ ") powder while stirring. After dissolution, vacuum filtration was performed with filter paper No. 5C. An artificial MgCl ₂ solution obtained by filtration was collected in an amount of 1310 mL, and 510 mL of an 8.3 N NaOH solution was slowly added to the mixture with stirring (the molar ratio of Mg ²⁺ to OH ⁻ was 1: 1.8). Further, pure water was added to prepare a 2 L suspension. This suspension was poured into an autoclave having a 3 L capacity Hastelloy C-276 wetted part and subjected to hydrothermal treatment at 170 ° C. for 5 hours under stirring.

The slurry after hydrothermal treatment was vacuum filtered, and then thoroughly washed with 20 times or more of pure water with respect to the solid content. Thereafter, it was returned again to pure water, and an emulsified slurry having an Mg (OH) ₂ solid content concentration of 10 g / dL was prepared. 1 L of this emulsified slurry was collected in a ₂ L container made of SUS316 (corresponding to 100 g as the Mg (OH) ₂ solid content mass), and the slurry was heated to 80 ° C. while stirring. Thereafter, 2.8% by mass of stearic acid aqueous solution prepared to 5% by mass at 80 ° C. as the stearic acid is added to the Mg (OH) ₂ solid mass and stirred at 80 ° C. for 1 hour for surface treatment. went. Then, it vacuum-filtered and wash | cleaned with the pure water 5 times or more capacity | capacitance with respect to Mg (OH) ₂ solid content mass. After washing, drying and pulverization gave Mg (OH) ₂ powder (a flame retardant of the present invention).
Table 1 shows analytical values of each composition in the 3.8N-HCl solution and general-purpose Mg (OH) ₂ powder used for dissolution, the prepared artificial MgCl ₂ solution, and the 8.3N-NaOH solution used for suspension generation. . Note that “%” and “ppm” in Table 1 and Tables 2 and 3 described later mean mass% and mass ppm, respectively.

(Production of flame retardant resin composition and molded body)
140 masses of flame retardant powder described above with respect to 100 mass parts of ethylene-vinyl acetate copolymer (Mitsui / DuPont Polychemical Co., Ltd., trade name: EV-360, vinyl acetate content: 25 mass%, MFR: 2) After mixing and mixing the parts, using a Laboplast mill (manufactured by Toyo Seiki Co., Ltd.), the mixture was kneaded at 150 ° C. for 5 minutes at a rotation speed of 50 rpm, and press molded at 150 ° C. to obtain a molded body. The molded body for the combustion test by the oxygen index method was a 3 mm thick sheet.

(Analysis and evaluation method)
Various raw materials, flame retardants and molded products were analyzed and evaluated as follows. The results are shown in Table 2 for Example 1 and Examples 2 to 5 described later.
(1) Analysis of iron and phosphorus in various raw materials and flame retardants Iron analysis method: ICP method was used.
Phosphorus analysis method: molybdenum blue method and ammonium vanadomolybdate method were used.

(2) Measurement of BET specific surface area and average particle diameter The BET specific surface area of the obtained flame retardant powder was measured by a nitrogen adsorption method, and the average particle diameter was measured by a particle size distribution meter.

(3) Oxygen Index of Molded Body The above-mentioned 3 mm-thick molded body was punched into a shape of 150 mm length × 6.5 mm width to make a test piece, and the oxygen index was measured according to JIS K7201. When the oxygen index is high, it means that flame retardancy is high. For example, in the above formulation, the oxygen index that can pass the UL-94 standard vertical combustion test (V-1) is 38.0 or more. Preferably there is.

(4) Degree of Char Formation of Molded Body During the measurement of the oxygen index, the degree of char (carbonized film) formation was visually observed. The case where char is likely to be generated is marked as ◯, and the case where char is hardly generated is marked as x. Incidentally, the higher the degree of char generation, the higher the oxygen index, which is preferable.

(5) Color Tone of Molded Body The obtained molded body was visually evaluated as ◯ when it was recognized that toning was possible, and conversely, it was evaluated as x when it was difficult to color toned.

(6) Surface appearance of molded body The surface appearance of the obtained molded body was evaluated by touching with a finger. A sample having a smooth surface was evaluated as ◯, and a sample having a rough surface was evaluated as ×.

[Example 2]
In a 3 L polyethylene container, weigh 480 g of high-purity MgCl ₂ · 6H ₂ O salt (manac) and 0.118 g of Na ₂ HPO ₄ , add 1 L of pure water and stir to prepare an MgCl ₂ solution. did. To this, 630 mL of a Ca (OH) ₂ slurry having a concentration of 25 g / dL was slowly added with stirring (Mg ²⁺ mol number: OH ^- mol number is 1: 1.8), and pure water was further added. A flame retardant and a molded product were produced in the same manner as in Example 1 except that a 2 L suspension was prepared, and analyzed and evaluated. Table 1 shows analytical values of the high purity MgCl ₂ .6H ₂ O salt and the Ca (OH) ₂ slurry used for the production of the suspension.

[Example 3]
In a 3L polyethylene container, weigh 480g of high-purity MgCl ₂ · 6H ₂ O salt (manac), 0.280g of FeCl ₃ · 6H ₂ O and 0.298g of Na ₂ HPO ₄ and add 1L of pure water. In addition, stirring was performed to prepare an MgCl ₂ solution. To this, 510 mL of an 8.3N-NaOH solution was slowly added with stirring (Mg ²⁺ mol number: OH ^- mol number was 1: 1.8), and pure water was further added to prepare a 2 L suspension. Except for the above, flame retardants and molded articles were produced in the same manner as in Example 1, and analyzed and evaluated.

[Example 4]
Put 1L of pure water into a 2L capacity SUS316 container and add 100g of Brucite powder with BET specific surface area of 14.3m ² / g and average particle size of 1.8μm in small amounts while stirring. After slurrying, the slurry was heated to 80 ° C. with stirring. On the other hand, 0.175 g of Na ₂ HPO ₄ was weighed and added to a 200 mL glass beaker filled with 100 mL of pure water, stirred with a magnetic stirrer, and this dissolved aqueous solution was heated to 80 ° C. Except that the whole amount was added to the slurry under stirring, a flame retardant and a molded product were produced in the same manner as in Example 1, and analyzed and evaluated. The analysis values of the used brucite powder are shown in Table 1.

[Example 5]
To 1310 mL of the artificial MgCl ₂ solution obtained in the same manner as in Example 1, 510 mL of an 8.3 N NaOH solution was slowly added with stirring (Mg ²⁺ mol number: OH ^- mol number was 1: 1.8). 2) Suspension was prepared by adding pure water. This suspension was poured into an autoclave having a 3 L capacity Hastelloy C-276 wetted part and subjected to hydrothermal treatment at 170 ° C. for 5 hours under stirring. On the other hand, 0.489 g of FeCl ₃ .6H ₂ O and 0.462 g of Na ₂ HPO ₄ were weighed and added to a 200 mL glass beaker filled with 100 mL of pure water, stirred with a magnetic stirrer, and this dissolved aqueous solution. Was added to the slurry after the hydrothermal treatment under stirring and stirred for 1 hour, and the same operation as in Example 1 was performed to produce a flame retardant and a molded body, which were analyzed and evaluated.

[Comparative Example 1]
A flame retardant was prepared in the same manner as in Example 3 except that FeCl ₃ .6H ₂ O and Na ₂ HPO ₄ were not added, and a molded article was produced in the same manner as in Example 1 for analysis and evaluation. Went. The analysis value of the obtained flame retardant powder and the evaluation result of the molded product are shown in Table 3 together with Comparative Examples 2 to 7 described later.

[Comparative Example 2]
Except that 0.124 g of Na ₂ HPO ₄ was weighed and added, the same procedure as in Example 3 was performed to prepare a flame retardant, and a molded article was produced in the same manner as in Example 1, and analyzed and evaluated. .

[Comparative Example 3]
FeCl ₃ .6H ₂ O (1.525 g) and Na ₂ HPO _{4 (} 0.265 g) were weighed, added to a 200 mL glass beaker filled with 100 mL of pure water, stirred with a magnetic stirrer, and dissolved. A flame retardant was prepared by performing the same operation as in Example 1 except that the aqueous solution was added to the slurry after hydrothermal treatment obtained by performing the same operation as in Comparative Example 1 and stirred for 1 hour. Molded bodies were manufactured and analyzed and evaluated.

[Comparative Example 4]
A flame retardant was prepared in the same manner as in Example 2 except that Na ₂ HPO ₄ was not added, and a molded article was produced in the same manner as in Example 1 for analysis and evaluation.

[Comparative Example 5]
A flame retardant was prepared and carried out in the same manner as in Example 4 except that Na ₂ HPO ₄ was not added to the prepared Brusite slurry (corresponding to 100 g as the solid mass of Mg (OH) ₂ ). After the molded body was produced in the same manner as in Example 1, analysis and evaluation were performed.

[Comparative Example 6]
The same operation as in Example 4 was performed except that 0.637 g of Na ₂ HPO ₄ was weighed and added under stirring to the prepared Brusite slurry (corresponding to 100 g as the solid mass of Mg (OH) ₂ ). A flame retardant was prepared, a molded body was produced in the same manner as in Example 1, and analyzed and evaluated.

[Comparative Example 7]
To 1310 mL of the artificial MgCl ₂ solution obtained in the same manner as in Example 1, 630 mL of a Ca (OH) ₂ slurry having a concentration of 25 g / dL was slowly added with stirring (Mg ²⁺ mol number: OH ^- mol number is 1: 1.8) and a flame retardant as in Example 1 except that pure water was added to prepare a 2 L suspension, and hydrothermal treatment was performed at 140 ° C. for 5 hours under stirring in an autoclave. And a molded object was manufactured and analyzed and evaluated.

(Evaluation results)
From Examples 1 to 5 shown in Table 2, the molded body made of the flame retardant resin composition of the present invention is very excellent in flame retardancy, and is excellent in toning because it is not colored, and further, dispersion of the flame retardant Therefore, it can be seen that the appearance of the molded body is also excellent.
On the other hand, from Table 3, in Comparative Example 1, since the content of the iron compound and the phosphorus compound contained in the magnesium hydroxide particles is small, the degree of char formation is small, and as a result, the oxygen index is low, and flame retardancy is achieved. Inferior to Further, in Comparative Example 2, the content of the phosphorus compound contained in the magnesium hydroxide particles is within a predetermined range, but since the content of the iron compound is small, the flame retardancy is poor as in Comparative Example 1. In Comparative Example 3, the content of the phosphorus compound contained in the magnesium hydroxide particles is within a predetermined range, but since the content of the iron compound is too large, the coloring is intense and the toning of the molded product is difficult. . In Comparative Examples 4 and 5, the content of the iron compound contained in the magnesium hydroxide particles is within a predetermined range, but since the content of the phosphorus compound is small, the degree of char generation is small, resulting in flame retardancy. Inferior. In Comparative Example 6, the content of the iron compound in the magnesium hydroxide particles is within a predetermined range, but the content of the phosphorus compound is too large, so that the magnesium hydroxide particles are difficult to disperse in the molded body. It causes poor appearance of the body. In Comparative Example 7, the content of the iron compound and the phosphorus compound in the magnesium hydroxide particles is within a predetermined range, but the average particle diameter and the BET specific surface area of the magnesium hydroxide are too large. Dispersion failure is caused, and the appearance of the molded body is poor.

  The flame retardant, the flame retardant resin composition, and the molded product of the present invention can be suitably used in fields where severe flame retardancy is required, such as for covering electric wires or housings for home appliances.

Claims (5)

(A) The content of the iron compound is 100 to 1000 ppm by mass in terms of iron atoms,
(B) The content of the phosphorus compound is 100 to 1000 ppm by mass in terms of phosphorus atoms,
(C) The specific surface area according to the BET method is 1 to 15 m ² / g,
(D) The average particle size is 0.5-2 μm.
A flame retardant comprising magnesium hydroxide particles. The flame retardant according to claim 1,
Content of the said iron compound and phosphorus compound is 200-1200 mass ppm converted into an iron atom and a phosphorus atom, The flame retardant characterized by the above-mentioned. In the flame retardant according to claim 1 or 2,
The magnesium hydroxide particles are surface-treated with at least one surface treatment agent selected from higher fatty acids, higher fatty acid metal salts, surfactants, coupling agents, esters of polyhydric alcohols, and phosphate esters. A flame retardant characterized by   A flame retardant resin composition comprising 5 to 500 parts by mass of the flame retardant according to any one of claims 1 to 3 with respect to 100 parts by mass of a synthetic resin.   The molded object which consists of a flame-retardant resin composition of Claim 4.