JPH0747736B2 - Flame retardants - Google Patents

Description

TECHNICAL FIELD The present invention relates to a combustible polymer material comprising a brominated aromatic crosslinked polymer in which a bromine atom is bonded to an aromatic crosslinked polymer in a specific bond form and content. And a flame retardant for forming a flame-retardant resin molded product. More specifically, when blended with a flammable polymer and molded into a resin molded product, its own heat stability and a stable molten state with respect to the flammable polymer are realized, especially non-corrosiveness to metal,
Further, the present invention relates to a flame retardant comprising a brominated aromatic crosslinked polymer, which is extremely excellent in various aspects such as mechanical properties of the resin molded product.

Problems to be Solved by Prior Art and Inventions Flame retardants of combustible polymer materials such as plastics and rubbers have extremely great industrial utility as materials indispensable in the fields of electricity, electronics, etc. Flame retardants are being investigated.

Examples of such conventional flame retardants include organic bromine flame retardants such as decabromodiphenyl ether, tetrabromobisphenol A, and hexabromobenzene. However, when such an organic bromine flame retardant is applied to a saturated polyester resin (for example, polyethylene terephthalate resin or polybutylene terephthalate resin) or a polyamide resin (for example, nylon 6 or nylon 66) having a high molding temperature, it is difficult to mold it. At this time, there are technical problems such as causing troubles such as coloring, decomposition, sublimation of the flame retardant itself, and significantly reducing the commercial value due to the phenomenon (blooming phenomenon) of the flame retardant migrating to the surface of the obtained resin molded product. there were.

As a result of various technical studies to solve such problems, technical means for further increasing the molecular weight of the flame retardant itself,
That is, a technical means using an oligomer type or polymer type flame retardant such as brominated epoxy oligomer (Japanese Patent Publication No. 57-39264) brominated polycarbonate, brominated polyphenylene or brominated polystyrene has been proposed. It has been found that blooming, sublimation, etc. can be prevented.

However, as described above, when any of the organic halogen-based, oligomer-type, and polymer-type flame retardants is used, when a resin molded product containing them is ignited and combustion starts, the phenomenon of melt sag ( The basic problem that the drip phenomenon) occurs and the flame retardant performance is significantly impaired has not been solved.

In order to solve this problem, a method has recently been proposed in which a bromide of an aromatic cross-linked polymer that does not melt by heat, in particular, a brominated cross-linked polystyrene having a three-dimensional structure is used as a flame retardant. (JP-A-60-65063).

However, although the flame retardant is recognized to have the advantage of not being melted by heat, denaturation, coloring, decomposition, etc. due to heating occur,
There have been recognized technical obstacles associated with such thermal instability. That is, when the brominated cross-linked polystyrene is blended as a flame retardant with a polyester resin, a polyamide resin, etc., and molded, corrosive thermal decomposition products such as hydrobromic acid generated from the flame retardant cause flammability of the polyester resin, etc. The thermal decomposition of the water-soluble polymer is induced, causing a decrease in molecular weight, coloring, etc.
As a result, it has been pointed out that there is a problem that the quality of the obtained resin molded product is significantly impaired.

As a means for solving such problems, a porous aromatic crosslinked polymer is subjected to a bromination reaction with molecular bromine or bromine chloride at low temperature in the presence of a catalyst such as aluminum chloride or ferric chloride. , A method of improving thermal stability by binding a bromine atom to an aromatic nucleus as selectively as possible and reducing thermal decomposition of the brominated aromatic cross-linked polymer (JP-A-61-211318). , 61-211361), even with such means, that is, in the case of using an aluminum chloride or ferric chloride catalyst, the presence of unstable bound bromine is still large, and the intrinsic thermal stability and The reality is that the corrosiveness of metals has not been improved yet.

Further, regarding a selective nuclear bromination method of a polymer having an aromatic nucleus, a method of reacting bromine chloride in the presence of a Lewis acid catalyst (JP-A-57-53505 and JP-B-61-34723) is proposed. However, these are all related to the bromination of linear polystyrene (molecular weight 20000-500000),
The linear polystyrene bromide thus obtained has a large tendency to corrode metals under heating, in addition to the above-mentioned problem of melting by heating, and therefore metal corrosion in resin molding and electronic molding of the molded product. When used for parts,
There are practical limitations such as causing damage to electronic materials, and the above technical obstacles have not been virtually eliminated by any conventional means.

Means for Solving Problems Here, the inventors of the present invention have completely solved the above-mentioned unresolved restrictions, effectively make the flammable polymer flame-retardant, and have excellent mechanical properties and quality. As a result of continuing intensive studies to establish an industrial means for flame retardants that can provide resin molded products, the aromatic cross-linked polymer was brominated with bromine chloride in the presence of a catalyst such as antimony simple substance or antimony compound. We have found the fact that the purpose can be effectively achieved by a flame retardant composed of a specific brominated aromatic cross-linked polymer obtained by converting the above to the present invention and arrived at the present invention.

That is, the present invention is a brominated aromatic crosslinked polymer obtained by causing bromine chloride to act substantially on an aromatic crosslinked polymer in the presence of antimony alone or an antimony compound. And a combustible polymer material comprising a brominated aromatic crosslinked polymer having 30 to 75% by weight of a bromine atom bonded to the aromatic crosslinked polymer and having a content of unstable bond bromine of 1% by weight or less. Regarding flame retardants.

The unstable bond bromine content defined in the present invention is 220 ° C.,
A value indicating the amount of corrosive thermal decomposition products such as hydrobromic acid generated from a brominated aromatic cross-linked polymer under heating conditions for 1 hour as a percentage per unit weight of the polymer.

The aromatic crosslinked polymer in the present invention, styrene,
Aromatic monovinyl monomers such as vinyltoluene and vinylnaphthalene, divinylbenzene, trivinylbenzene,
Known polymerization of polyvinyl monomers such as divinyltoluene, divinyldiphenyl ether, ethylene glycol dimethacrylate, and trimethylolpropane trimethacrylate, and optionally one or more other monomers copolymerizable therewith. Polymerized by a method, or a linear aromatic polymer such as linear polystyrene is used by a known method such as Friedel-Crafts reaction to form a cross-linkage between polymer molecular chains. be able to.

The amount of the polyvinyl monomer used in the present invention is 1 to 50% by weight, preferably 1 to 20% by weight based on all vinyl monomers.
A range of wt% can be adopted. When more than 50% by weight of the polyvinyl monomer is used, the reaction of brominating the polymer becomes difficult due to the high degree of crosslinking, and a brominated aromatic crosslinked polymer having a desired bromine content is obtained. When the amount of the polyvinyl monomer used is less than 1%, it is difficult to purify and pulverize the polymer. Insoluble,
Since infusibility is lost, either case is not preferable.

In the present invention, the brominated aromatic crosslinked polymer can be made porous in order to facilitate pulverization and washing of the brominated aromatic crosslinked polymer. A known method can be adopted for the porosity, and the porosifying agent includes alcohols, hydrocarbons, benzene, toluene, sodium carbonate, ammonium carbonate and the like, which are directly involved in the polymerization reaction. It is possible to use organic and inorganic additives which are not present. The amount of the porosifying agent used can be 200% by weight or less, and more preferably 100% by weight or less, based on the total vinyl monomer. It is not preferable from the economical point of view.

Examples of the solvent used in the bromination reaction of the present invention include:
Known bromination reaction solvents such as dichloroethane, carbon tetrachloride, methylene chloride, methylene bromide and the like can be used.

Further, as the bromination reaction catalyst, antimony alone or Sb
_{Cl 3, SbBr 3, SbBr 5} , SbOBr, SbOCl , and the like, these antimony compounds alone or in combination each can be used, as is the amount used, the aromatic cross-linked polymer 0.01 -20% by weight, preferably 3-10% by weight can be used.

Therefore, when the amount of the catalyst used exceeds the range, it becomes difficult to wash and remove the catalyst in the post-treatment step of purifying the brominated aromatic crosslinked polymer thus produced, and the amount of the catalyst less than the range is used. If it is, the rate of the bromination reaction will be reduced, and in either case, it is not preferable.

Further, as the bromination reaction catalyst, when antimony simple substance or other than the antimony compound, for example, ferric chloride or aluminum chloride is used, the selectivity to nuclear bromination is decreased, and the content of unstable bound bromine is reduced. To increase.

In the bromination reaction of the present invention, bromine chloride can be used as a brominating agent. The bromine chloride can be isolated and used, a method of adding chlorine after adding bromine in advance, a method of adding bromine and chlorine at the same time, and the like. Any method can be adopted as long as chlorine is allowed to coexist, and as a result, conditions capable of forming bromine chloride are formed.

Thus, the bromination reaction of the present invention can be carried out in the temperature range of -20 to 100 ° C, preferably 0 to 50 ° C. When the reaction is carried out at a temperature lower than the above range, the reaction rate is lowered, and at a temperature exceeding the above range, bromine chloride is decomposed or scattered out of the reaction system, which is not preferable.

Thus, after binding a predetermined amount of bromine atom, the brominating agent and catalyst remaining in the reaction system are treated with water, NaOH, KOH, N.
a ₂ CO ₃ , NaOCH ₃ or the like is decomposed and removed with an alkali to isolate and purify only the brominated aromatic crosslinked polymer.

As the isolation method, any known method such as natural filtration, filter press, vacuum filtration, and column washing can be adopted. It is also possible to employ means such as steam distillation or azeotropic distillation with water in order to remove and recover the residual reaction solvent.

The brominated aromatic cross-linked polymer is then used as a flame retardant of the present invention after being subjected to a pulverization treatment, if necessary, and a drying step.

The particle size of the flame retardant according to the present invention is 100
It is possible to use those having an average particle size of μ or less, preferably 20 μ or less.

If the average particle size exceeds the above range, the tensile strength, bending strength, flame retardancy of the resin molded product may be deteriorated, and this is not preferable.

In addition, as a method for pulverizing to such a particle size, dry or wet pulverization is performed using a pulverizer such as a ball mill, a vibration mill and a pin mill, and as a drying method, vacuum drying, rotary drying, hot air drying are used. For example, any known method can be adopted.

The flame retardant according to the present invention needs to have a bromine content of 30 to 75% by weight. When the bromine content is lower than the range, it becomes difficult to impart desired flame retardancy to the resin molded product, and it is substantially difficult to achieve the bromine content exceeding the range. The bromine content for more suitably achieving the object of the present invention may be in the range of 50 to 70% by weight, more preferably 60 to 70% by weight.

Here, the above-mentioned bromine content is determined by burning a polymer sample according to the oxygen flask burning method of JIS K-6388 and measuring the silver nitrate consumption of the absorbing liquid.

The unstable bound bromine content defined in the present invention is an index relating to the thermal stability of the bound bromine atom, and corrosive thermal decomposition products such as hydrobromic acid generated by the brominated aromatic crosslinked polymer under heating. The amount of the product is measured and evaluated. Here, the index is considered to relate to the bond form of the bromine atom, that is, the aromatic nucleus selectivity of the bromination reaction and the like.

The measurement is performed by the following method. That is, 10 g of the brominated aromatic crosslinked polymer was placed in a test tube and heated at 220 ° C. for 1 hour in a nitrogen stream to absorb the generated acidic component in a dilute alkaline aqueous solution, and the above bromine content was measured for this absorption liquid. As in the case, the consumption of silver nitrate is measured and converted as the amount of hydrobromic acid.

Therefore, the flame retardant in the present invention needs to have an unstable bond bromine content of 1% by weight or less. When a brominated aromatic crosslinked polymer having an unstable bond bromine content in the above range is used as a flame retardant, it lacks thermal stability of itself, and the polymer is blended with a flammable polymer. In order to achieve the object of the present invention, when molding into a resin molded product, it induces a decrease in molecular weight, coloring, etc. in the polymer, and the mechanical properties, color tone and other qualities of the resin molded product thus obtained are significantly reduced. Can not do it. The labile bond bromine content for more preferably achieving the object of the present invention is 0.5
It is preferably in the range of not more than wt%, more preferably not more than 0.3 wt%.

The color tone of the flame retardant according to the present invention is one measure for evaluating the thermal stability of the flame retardant, and the brominated aromatic crosslinked polymer is
After heat treatment at 0 ° C. for 1 hour, it is determined by measuring the L value with a color difference meter. Thus, as the flame retardant of the present invention, a brominated aromatic crosslinked polymer having an L value of 70 or more, preferably 80 or more can be used, and an L value of less than this range can be used.
When the value is a value, the color tone is deteriorated by heat denaturation during molding of the resin molded product, which is not preferable.

In addition, the flame retardant of the present invention has an L value after heat treatment of 70 or more, whereas unlike the bromination method using bromine chloride of the present invention, a catalyst other than molecular bromine or an antimony catalyst is used. The L value of the flame retardant obtained by bromination was low, and especially the L value after heat treatment was as low as 70 or less.

The pH of the brominated aromatic crosslinked polymer in the present invention is an index relating to the amount of ionic impurities contained in the polymer and the like, and the measurement is carried out by the following method. That is, 10 g of the brominated aromatic cross-linked polymer was dispersed in a mixed solution of 170 ml of distilled water and 30 ml of ethanol, boiled at 90 to 100 ° C. for 1 hour, then allowed to stand and cool, and the pH of the supernatant was adjusted to pH. Measure with a meter.

Therefore, in the flame retardant of the present invention, the preferable pH of the brominated aromatic crosslinked polymer is 4 to 10. When a polymer having a pH range outside this range is used, it is molded into a resin molded product. In this case, it is not preferable because it promotes coloring and thermal decomposition of the flammable polymer and deteriorates quality such as mechanical properties of the resin molded product thus obtained.

According to the method of bromination using the above-mentioned molecular bromine or a catalyst other than the antimony catalyst of the present invention, the pH is 4
The following is not preferable because a brominated aromatic crosslinked polymer having a suitable pH range of the present invention cannot be formed.

In order to make a flammable polymer material flame-retardant by the flame retardant according to the present invention, the flame retardant is added to 100 parts by weight of the polymer material according to the flame retardance performance required for a resin molded product. Can be appropriately selected from the range of 5 to 100 parts by weight. However, if the amount used is less than the above range, it becomes difficult to obtain the required flame retardancy, and if the amount used exceeds the range, the mechanical properties of the molded product will be impaired. Is also not preferable. Regarding the method of using the flame retardant, this flame retardant can be used alone or in combination with other flame retardants.

Further, it is also possible to use known antimony trioxide, antimony pentoxide, hydrated aluminum, molybdenum oxide and the like in combination as the flame retardant aid.

Further, use of organic or inorganic fibrous reinforcing materials such as glass fiber, mica, carbon fiber and asbestos, and further resin additives such as antioxidants, heat stabilizers, light stabilizers, plasticizers and colorants. There is no problem.

The flame retardant according to the present invention is blended with a combustible polymer material, and as a method for molding and processing, a combustible polymer, a flame retardant, and, if necessary, various components as described above are adjusted to a predetermined mixing ratio. After kneading using an extruder or the like, if necessary, pelletization can be performed, and this can be molded by a known method such as injection, extrusion or compression.

Effect The present invention is a flame retardant comprising a brominated aromatic crosslinked polymer having 30 to 75% by weight of a bromine atom bonded to an aromatic crosslinked polymer and having a content of unstable bond bromine of 1% by weight or less. Therefore, while exhibiting an excellent effect on making various flammable polymer materials flame-retardant, at the same time when blended with a flammable polymer material and molded into a resin molded product, its thermal stability, It is possible to provide a resin molded product that is extremely excellent in various aspects such as achieving a stable molten state with respect to polymer materials and noncorrosiveness with respect to metals, and having excellent mechanical properties, color tone and other qualities.

Furthermore, since the flame retardant of the present invention is a brominated aromatic cross-linked polymer having a three-dimensional structure, its unique insolubility and infusibility make it excellent in terms of safety such as effects on living bodies. it can.

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

Synthesis of Aromatic Crosslinked Polymer Four kinds of aromatic crosslinked polymers, which are raw material resins of the present invention, were produced by the following various methods.

1) Take 500 ml of water and 1 g of polyvinyl alcohol in a reactor and heat to 80-90 ° C with stirring, and prepare 10 g of styrene, 1.0 g of divinylbenzene, 5 g of toluene, 5 g of dodecane, and benzoyl peroxide. 0.2 g of the mixed solution was added, the mixture was vigorously stirred at 80 to 90 ° C., the polymerization was continued for 24 hours, and then filtered, washed with hot water, and dried to obtain 10 g of a polymer [abbreviated as Polymer I]. ].

2) Using the same method as in 1) above, except that 2.0 g of divinylbenzene was used and 1 g of azobisisobutyronitrile was used instead of benzoyl peroxide, 12 g of
To obtain a polymer [abbreviated as polymer II].

3) 10 g of a polymer was obtained by the same method as in the above 1) except that the porosity-imparting agents toluene and dodecane were not added [abbreviated as polymer III].

4) 10 g of a polymer was obtained by the same method as in Example 1) except that dodecane was not added [abbreviated as polymer IV].

5) 10 g of a polymer was obtained by the same method as 1) except that vinyltoluene was used in place of styrene [abbreviated as polymer V].

Synthesis of Brominated Aromatic Crosslinked Polymer 1) While stirring a suspension of Polymer I 25 g, dichloroethane 100 ml and antimony trichloride 1.25 g,
After adding 60 g of bromine chloride at -20 ° C for 3 hours and aging for about 1 hour after the addition of bromine chloride was completed, and then neutralized by adding 20 ml of water, followed by addition of 43.3 g of 48% -NaOH, The resulting brominated aromatic crosslinked polymer was filtered, washed with dichloroethane, then dried and pulverized, and was composed of a white powdery brominated aromatic crosslinked polymer with a bromine content of 65%, 63 g of the flame retardant of the present invention. Was obtained (indicated by symbol A in Table 1).

2) Take 25 g of polymer IV, 200 ml of methylene chloride, 1.2 g of antimony oxychloride in a reactor, add 40 g of bromine at 25 to 35 ° C. for about 10 minutes while stirring, and then introduce 9 g of chlorine over 2 hours ( (The temperature during the introduction is adjusted to 25-35 ℃), and then 20 ml of water and then 48% -NaOH 21 g are added for neutralization, followed by filtration, drying and crushing treatment to obtain a white powdery substance with a bromine content of 61%. 62 g of the flame retardant of the present invention consisting of a brominated aromatic crosslinked polymer was obtained (denoted by symbol B in Table 1).

3) Except for using Polymer II and using 35 g of bromine chloride, the procedure was exactly the same as in 1) above, and it consisted of a white powdery brominated aromatic cross-linked polymer with a bromine content of 46%. , 48 g of the flame retardant of the present invention was obtained (symbol C in Table 1
Will be displayed at).

4) 65 g of the flame retardant of the present invention, which is composed of a white powdery brominated aromatic cross-linked polymer with a bromine content of 69%, is prepared by the same procedure as in 1) except that the polymer III is used. Obtained (indicated by symbol D in Table 1).

5) A commercially available styrene-divinylbenzene copolymer as an aromatic cross-linked polymer (trade name: Amberlite XAD-
A brominated styrene-divinylbenzene-based copolymer in the form of a white powder having a bromine content of 42% was prepared by the same procedure as in 1) except that 2) was used and 33 g of bromine chloride was used. 42 g of flame retardant was obtained (indicated by symbol E in Table 1).

6) Unlike the bromination method using bromine chloride of the present invention,
61 g of a flame retardant composed of a brown powdery brominated aromatic cross-linked polymer having a bromine content of 65% was obtained by the same procedure as 1) except that 108.5 g of molecular bromine was used. Indicated by symbol P in Table 1) (Comparative example).

7) Instead of antimony trichloride, aluminum chloride 1.
By the same operation as 1) except that 25 g was used, 62 g of a flame retardant composed of a brominated aromatic cross-linked polymer in the form of a pale yellow powder having a bromine content of 66% was obtained (in Table 1). It is indicated by the symbol Q) (comparative example).

8) By the completely same operation as the above 1), except that 1.25 g of ferric chloride was used instead of antimony trichloride.
60 g of a flame retardant composed of a brown powdered brominated aromatic cross-linked polymer having a bromine content of 61% was obtained (denoted by symbol R in Table 1) (Comparative Example).

As is clear from Table 1, by adopting the preferred method for carrying out the present invention, it is possible to obtain a brominated aromatic crosslinked polymer having a reduced content of unstable bond bromine, good appearance and good color tone. Recognize.

9) Using the same procedure as in 1) above except that the polymer V was used, 64 g of the flame retardant of the present invention consisting of a white powdery brominated aromatic crosslinked polymer having a bromine content of 66% was obtained. Obtained (indicated by symbol F in Table 1). When the flame retardant F was blended with a polyethylene terephthalate resin and a nylon 66 resin and the physical properties of the obtained resin molded product were evaluated, the flame retardancy, mechanical properties and color tone were excellent.

Evaluation of Flame Retardancy and Mechanical Properties of Resin Molded Products The flame retardant composed of the brominated aromatic cross-linked polymer of the present invention was blended with polyethylene terephthalate resin and nylon 66 resin, and the flame resistance and mechanical properties of the resin molded products obtained The characteristics were evaluated.

1) Polyethylene terephthalate resin (Intrinsic viscosity 0.5
8, melting point 260 ° C.) The flame retardants A to E of the present invention and the comparative flame retardant P are used, respectively, and antimony trioxide and a glass fiber having a length of 3 mm (made by Asahi Glass Fiber, chopped strand 486A) are used. The composition ratios shown in Table 2 were mixed.

The cylinder temperature of the twin-screw extruder was adjusted to 280 ° C., the above mixture was melt-kneaded, and then pelletized.

The obtained pellets were dried under reduced pressure at 120 ° C for 24 hours, then supplied to an injection molding machine adjusted to a cylinder temperature of 275 ° C and a mold temperature of 90 ° C, and molded into a test piece with an average residence rate in the cylinder of 20 seconds. . The mechanical property values of the 6 types of test pieces thus obtained are shown in Table 2.

Here, the mechanical property value was measured by the following method. The flame retardancy was measured by US flame retardancy test method UL-94, and it is shown that VO in Table 2 self-extinguishes within 10 seconds after ignition and there is no drip phenomenon.

Tensile strength: ASTM D-638 Bending strength: ASTM D-790 Retention rate: When the retention time was extended to 30 minutes compared to the tensile strength of the above test piece molded with an average residence time of 20 seconds in the cylinder Retention rate of tensile strength of.

2) Nylon 66 resin pellets (manufactured by DuPont Far East Co., Ltd.) were used to prepare test pieces in the same manner as in the case of the polyethylene terephthalate resin.

The mechanical property values of the test pieces thus obtained are shown in Table 3.

As is clear from Tables 2 and 3, by using the flame retardant of the present invention, a resin molded product having excellent flame retardancy and mechanical properties can be obtained, and the residence time in the molding machine can be prolonged. However, since the strength reduction of the obtained molded product is small, the flame retardant achieves a stable molten state without promoting deterioration of flammable polymers such as polyethylene terephthalate and nylon 66 due to heat. I understand.

Evaluation of Metal Corrosion Resistance of Flame Retardant Flame Retardants 1 to F of the Present Invention, Comparative Flame Retardants P and Q, and Brominated Linear Polystyrene (Linear polystyrene having a molecular weight of 58,000 measured by gel permeation chromatography is converted into dichloroethane. Dissolve and brominate with bromine chloride by the same operation as in the case of the synthesis of the flame retardant A of the present invention, neutralize the obtained brominated linear polystyrene solution with NaOH, and then add it to water to perform heavy Re-precipitate the coalescence, then filter, wash, dry,
3g each and a piece of copper (width 5mm x)
(30 mm length x 5 mm thickness) is taken in a 50 cc glass bottle with a sealed stopper, and 2
Table 4 shows the results of the surface corrosion test of copper pieces when heated at 20 ° C for 1 hour.

◯: No corrosiveness is observed ×: Remarkable corrosiveness is recognized As is clear from Table 4, the flame retardant of the present invention has excellent non-corrosion properties against copper, and is a brominated aromatic cross-linked polymer. Even if, as in the present invention, not brominated with bromine chloride, or even brominated with bromine chloride, using a catalyst other than an antimony catalyst as a catalyst, or It can be seen that the linear brominated polystyrene causes copper corrosion, and the flame retardant of the present invention is excellent.

EFFECTS OF THE INVENTION The flame retardant of the present invention comprises a brominated aromatic crosslinked polymer having 30 to 75% by weight of a bromine atom bonded to an aromatic crosslinked polymer and having an unstable bromine content of 1% by weight or less. (1) Flame retardation of various combustible polymer materials can be realized, (2) Molded products having excellent mechanical properties and color tone can be provided, and (3) Polymer material itself. It has excellent effects in that it can maintain a stable molten state, (4) is heat stable, and (5) does not corrode metal, especially copper, and is excellent in the electrical and electronic fields. A polymeric material can be provided.

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Claims (7)

[Claims] 1. A brominated aromatic crosslinked polymer obtained by brominating an aromatic crosslinked polymer substantially with bromine chloride in the presence of antimony alone or an antimony compound. It is difficult to form a combustible polymer material composed of a brominated aromatic crosslinked polymer having 30 to 75% by weight of a bromine atom bonded to the aromatic crosslinked polymer and having a content of unstable bond bromine of 1% by weight or less. Fuel. 2. The flame retardant according to claim 1, wherein the aromatic crosslinked polymer is obtained by copolymerizing 1 to 50% by weight of a polyvinyl monomer with respect to a monovinyl monomer. . 3. A cross-linked aromatic polymer obtained by copolymerizing vinyl monomers in the presence of a porosifying agent in an amount of 200% by weight or less based on all vinyl monomers. The flame retardant according to claim 1. 4. The flame retardant according to claim 1, wherein the brominated aromatic crosslinked polymer has a pH of 4-10. 5. A brominated aromatic cross-linked polymer is obtained by converting the polymer into
The flame retardant according to claim 1, which has a color tone of 70 or more as L value after heating at 0 ° C for 1 hour. 6. The flame retardant according to claim 1, wherein the combustible polymer material is a thermoplastic polyester resin. 7. The flame retardant according to claim 1, wherein the combustible polymer material is a thermoplastic polyamide resin.