Polybutadiene resin composition, polybutadiene cured product, and method for producing the same

Abstract

To provide a polybutadiene resin composition having superior dispersibility of flame retardants.SOLUTION: A polybutadiene resin composition is used, wherein the composition comprises 5 to 100 pts.wt. of a brominated flame retardant (B) represented by the following general formula (2), relative to 100 pts.wt. of a specific polybutadiene resin (A) having a number average molecular weight of 1,000 to 20,000. In the general formula (2), R represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-, and n represents an integer of 1 or more.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a flame-retardant polybutadiene resin composition.

Background Art

[0002] In recent years, with the increasing functionality of electronic devices, resin materials for forming wiring boards are required to have dielectric properties such as low dielectric constant and low dielectric tangent. For this reason, a thermosetting polybutadiene resin that does not contain heteroatoms in its molecular structure is used as the resin material. Since such a resin material is required to have flame retardancy, a polybutadiene resin composition obtained by adding a brominated flame retardant to a polybutadiene resin has been proposed.

[0003] For example, Patent Document 1 discloses a polybutadiene resin composition containing decabromodiphenylethane or ethylenebis(tetrabromophthalimide) as a brominated flame retardant.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a conventionally known polybutadiene resin composition, the brominated flame retardant tends to sediment, and it is necessary to constantly stir to ensure the uniformity of the composition, resulting in a problem of deteriorated workability. In addition, it has been difficult to obtain a flame-retardant polybutadiene cured product in which the brominated flame retardant is uniformly dispersed in the polybutadiene.

[0006] The present invention has been made in view of the above background art, and an object thereof is to provide a polybutadiene resin composition excellent in the dispersibility of a brominated flame retardant, and further a polybutadiene cured product in which the brominated flame retardant is uniformly dispersed.

Means for Solving the Problems

[0007] As a result of intensive studies, the present inventors have found that the following invention can solve the above problems and have completed the present invention.

[0008] That is, the present invention relates to a polybutadiene resin composition shown below. [1] A polybutadiene resin composition comprising 5 to 100 parts by weight of a bromine-based flame retardant (B) represented by the following general formula (2) with respect to 100 parts by weight of a polybutadiene resin (A) having a number average molecular weight of 1,000 to 20,000 and having a repeating unit represented by the following general formula (1).

[0009] [Chemical formula]

[0010] [Chemical formula]

[0011] (In the formula, R represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-, and n represents an integer of 1 or more.) [2] The polybutadiene resin composition according to [1], wherein the weight average molecular weight in terms of standard polystyrene measured by gel permeation chromatography of the bromine-based flame retardant (B) is 1,000 to 20,000. [3] The polybutadiene resin composition according to [1] or [2], wherein in the general formula (2), R is an alkylene group having 1 to 6 carbon atoms. [4] The polybutadiene resin composition according to any one of [1] to [3], wherein in the general formula (2), R is a 2,2-propylene group. [5] The polybutadiene resin composition according to any one of [1] to [4], which contains an organic peroxide. [6] A polybutadiene cured product formed from the resin composition according to any one of [1] to [5]. [7] A polybutadiene cured product containing polybutadiene and the brominated flame retardant (B) represented by the general formula (2), wherein the brominated flame retardant (B) is uniformly dispersed in the cured product. [8] A method for producing a polybutadiene cured product, comprising heating, pressurizing, or hot pressing the polybutadiene resin composition according to any one of [1] to [4] in the presence of an organic peroxide.

Advantages of the Invention

[0012] The polybutadiene resin composition of the present invention has an effect of being excellent in the dispersibility of the brominated flame retardant as compared with conventionally known polybutadiene resin compositions. Further, by using the polybutadiene resin composition of the present invention, a polybutadiene cured product in which the brominated flame retardant is uniformly dispersed can be obtained.

Modes for Carrying Out the Invention

[0013] Hereinafter, the present invention will be described in more detail.

[0014] One aspect of the present invention relates to a polybutadiene resin composition comprising 100 parts by weight of a polybutadiene resin (A) having a number average molecular weight of 1,000 to 20,000 and having a repeating unit represented by the following formula (1), and 5 to 100 parts by weight of a brominated flame retardant (B) represented by the following formula (2).

[0015]

Chemical formula

[0016]

Chemical formula

[0017] (In the formula, R represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-, and n represents an integer of 1 or more.) The polybutadiene resin (A) used in the present invention includes polybutadiene having a number average molecular weight of 1,000 to 20,000. In particular, from the viewpoint of curability, polybutadiene containing 85% or more of 1,2-butadiene units represented by the formula (1) is preferred. The repeating units other than the 1,2-butadiene units that can be contained in the crosslinking component (A) are not particularly limited, and examples thereof include cis-1,4-butadiene units or trans-1,4-butadiene units.

[0018] The brominated flame retardant (B) of the present invention is represented by the general formula (2). In the general formula (2), the C1-C6 alkylene group represented by R is not particularly limited, and examples thereof include a methylene group, an ethylene group, a 2,2-propylene group, a 2,2-butylene group, a hexadiene group, or a 1,1-cyclohexylene group.

[0019] Regarding R, from the viewpoint of excellent heat resistance, it is preferably a 2,2-propylene group.

[0020] In the general formula (2), n represents the average value of the number of repetitions of the repeating unit of the brominated flame retardant (B). In the present invention, n represents an integer of 1 or more.

[0021] Regarding the n, from the viewpoint of excellent flame retardancy and heat resistance of the resin containing the brominated flame retardant (B), it is preferably an integer of 1 or more from 3 to 40, more preferably an integer of 1 or more from 3 to 30, and even more preferably an integer of 1 or more from 4 to 15.

[0022] For example, when R is a 2,2-propylene group, the terminal structure is a 2-chloroethyl group, and n is 10, the theoretical average molecular weight of the brominated flame retardant (B) of the present invention is 5,798.

[0023] The brominated flame retardant (B) of the present invention preferably has a weight average molecular weight in terms of standard polystyrene measured by gel permeation chromatography of 1,000 to 20,000, more preferably 2,000 to 18,000, and even more preferably 3,000 to 16,000, in that it is excellent in the flame retardancy and heat resistance of the resin to which it is blended.

[0024] Regarding the brominated flame retardant (B) of the present invention, in terms of obtaining higher heat resistance, the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) in terms of standard polystyrene measured by gel permeation chromatography is preferably 1.0 to 4.0, more preferably 1.0 to 3.0, and even more preferably 1.0 to 2.5.

[0025] The method and conditions for measuring the weight average molecular weight of the brominated flame retardant (B) of the present invention by gel permeation chromatography complied with ISO 16014-3:2012 (JIS K 7252-3:2016). The said method and conditions are described in more detail in the examples.

[0026] Regarding the brominated flame retardant (B) of the present invention, in terms of expecting high flame retardancy, its bromine content is preferably 50 to 60% by weight, and more preferably 52 to 60% by weight.

[0027] The brominated flame retardant (B) of the present invention is not particularly limited, but as an example, a mixture containing a compound represented by the following general formula (3), a compound represented by the following general formula (4), a base, a radical trap agent, and a solvent can be produced by heating in the range of 110 to 150 °C while stirring.

[0028]

Chemical formula

[0029] (In the formula, R represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-.)

[0030] [Chem.]

[0031] (In the formula, X and Y represent halogen atoms.) The compound represented by the general formula (3) is not particularly limited, and examples thereof include tetrabromobisphenol A, tetrabromobisphenol F, or bis(4'-hydroxy-3',5'-dibromophenyl) sulfone. Among these, tetrabromobisphenol A is preferable in that a brominated flame retardant (B) having excellent heat resistance can be obtained.

[0032] In the compound represented by the general formula (4), the halogen atoms represented by X and Y are not particularly limited, and examples thereof include chlorine, bromine, or iodine. Among these, chlorine is preferable in that a brominated flame retardant (B) having excellent heat resistance can be obtained.

[0033] The compound represented by the general formula (4) is not particularly limited, and examples thereof include dichloroethane, dibromoethane, diiodoethane, 1-bromo-2-chloroethane, 1-chloro-2-iodoethane, or 1-bromo-2-iodoethane.

[0034] In the production of the brominated flame retardant (B) of the present invention, the base is not particularly limited, and examples thereof include lithium hydroxide, potassium hydroxide, sodium hydroxide, cesium hydroxide, lithium hydrogen carbonate, potassium hydrogen carbonate, sodium hydrogen carbonate, cesium hydrogen carbonate, lithium carbonate, potassium carbonate, sodium carbonate, cesium carbonate, calcium hydroxide, strontium hydroxide, or barium hydroxide. Among these, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, or potassium hydrogen carbonate is preferable in that a halogenated polymer having excellent heat resistance can be obtained, and potassium carbonate is more preferable.

[0035] In the production of the brominated flame retardant (B) of the present invention, the solvent is not particularly limited as long as it does not react with the substrate, and examples thereof include aprotic polar solvents.

[0036] The aprotic polar solvent is not particularly limited, and examples thereof include tetrahydrofuran, dioxane, pyridine, N-methylpyrrolidone, propylene carbonate, dimethylacetamide, dimethylformamide, or dimethyl sulfoxide. Among these, N-methylpyrrolidone, dimethylacetamide, dimethylformamide, or dimethyl sulfoxide is preferable in terms of obtaining a halogenated polymer having excellent heat resistance.

[0037] In the production of the brominated flame retardant (B) of the present invention, the reaction temperature is preferably in the range of 110°C to 150°C, and more preferably in the range between 120°C and 145°C.

[0038] The radical scavenger is not particularly limited. For example, at least one radical scavenger selected from the group consisting of phenolic radical scavengers, quinone radical scavengers, phosphite radical scavengers, amine radical scavengers, and sulfur radical scavengers can be mentioned. More specifically, for example, 4-methoxyphenol, 6-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butylphenol, 2-tert-butyl-4-methoxyphenol, 4-tert-butylphenol, 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol (alias, dibutylhydroxytoluene), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 3,6-dihydroxybenzobornane, 2,2'-methylenebis(6-cyclohexyl-p-cresol), hydroquinone, tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 1,4-benzoquinone, 2-tert-butyl-1,4-benzoquinone, 4-tert-butylcatechol, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], diphenylamine, N,N-diethylhydroxylamine, ammonium nitrosophenylhydroxylamine, 2,2,6,6-tetramethylpiperidine-1-oxyl, 2-benzimidazolethiol, phenothiazine, didodecyl 3,3'-thiodipropionate, dioctadecyl 3,3'-thiodipropionate, triethyl phosphite, trihexyl phosphite, tris(1,1,1,3,3,3-hexafluoro-2-propyl) phosphite, triphenyl phosphite, tris(2-methylphenyl) phosphite, tris(4-methylphenyl) phosphite, tris(4-nonylphenyl) phosphite, pentaerythritol bis(2,4-di-tert-butylphenyl phosphite), or tris(2,4-di-tert-butylphenyl) phosphite, etc. can be mentioned.

[0039] In the production of the brominated flame retardant (B) of the present invention, the mixing ratio of the compound represented by the general formula (3) and the compound represented by the general formula (4) is preferably 0.8 to 2.0 mole parts of the compound represented by the general formula (4) with respect to 1 mole part of the compound represented by the general formula (3), more preferably 1.0 to 1.8 mole parts, and still more preferably 1.2 to 1.5 mole parts.

[0040] In the production of the brominated flame retardant (B) of the present invention, the amount of the base used is preferably 0.8 to 2.5 mole parts with respect to 1 mole part of the compound represented by the general formula (3), more preferably 0.9 to 2.0 mole parts, and still more preferably 1.0 to 1.8 mole parts.

[0041] In the production of the brominated flame retardant (B) of the present invention, the amount of the radical trap agent used is preferably 0.001 to 10 parts by mass, more preferably 0.005 to 8 parts by mass, and still more preferably 0.01 to 5 parts by mass with respect to 100 parts by mass of the compound represented by the general formula (3).

[0042] In the production of the brominated flame retardant (B) of the present invention, the amount of the solvent used is preferably 200 to 2,000 parts by mass, more preferably 250 to 900 parts by mass, and still more preferably 250 to 500 parts by mass with respect to 100 parts by mass of the compound represented by the general formula (3).

[0043] In the polybutadiene resin composition of the present invention, the mixing amount of the brominated flame retardant (B) with respect to the polybutadiene resin (A) is preferably 5 to 100 parts by weight, more preferably 10 to 80 parts by mass, and still more preferably 10 to 50 parts by mass with respect to 100 parts by weight of the polybutadiene resin (A). The organic peroxide of the present invention is not particularly limited as long as it is a compound capable of generating radicals for crosslinking the polybutadiene resin composition. For example, t-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butyl peroxybenzoate, di(2-t-butylperoxyisopropyl)benzene, dicumyl peroxide, t-butyl cumyl peroxide, cumyl peroxyneodecanoate, di-(3-methylbenzoyl)peroxide, benzoyl(3-methylbenzoyl)peroxide, and dibenzoyl peroxide, n-butyl 4,4-di-(t-butylperoxy)valerate, di-t-hexyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, di-t-butyl peroxide, etc. may be mentioned. As the mixing amount of the organic peroxide with respect to the polybutadiene resin (A), it is preferably 1 to 10 parts by weight, more preferably 2 to 8 parts by mass, and even more preferably 3 to 6 parts by mass with respect to 100 parts by weight of the polybutadiene resin (A). The resin composition of the present invention may further contain other components, for example, other resins (excluding polybutadiene), crosslinking agents, inorganic fillers, and stress relaxants, if necessary. Examples of other resins include polyphenylene ether resin, bismaleimide resin, bismaleimide-triazine resin, epoxy resin, benzocyclobutene resin, polytetrafluoroethylene resin, acrylic resin, etc. The crosslinking agent is not particularly limited, but examples include triallyl isocyanurate, triallyl cyanurate, diallyl monoalkyl isocyanurate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, triallyl trimellitate, bisvinylphenylmethane, 1,2-bis(m-vinylphenyl)ethane, 1,2-bis(p-vinylphenyl)ethane, 1-(p-vinylphenyl)-2-bis(m-vinylphenyl)ethane, divinylbenzene polymers having vinyl groups in the side chain, etc. The inorganic filler is not particularly limited, and examples thereof include metal oxides such as silica, boron nitride, talc, alumina, zirconia, and titania, nitrides, silicides, borides, and the like. The stress reliever is not particularly limited, and examples thereof include silicone resin particles and the like.

[0044] The polybutadiene resin composition of the present invention can be mixed with an organic solvent and used after being made into a varnish. The organic solvent for making the polybutadiene resin composition of the present invention into a varnish is preferably a good solvent for the polybutadiene resin (A), and examples thereof include tetrahydrofuran, toluene, xylene, cyclohexane and the like. The polybutadiene resin composition of the present invention can obtain a flame-retardant polybutadiene cured product (hereinafter sometimes abbreviated as "cured product") in which the brominated flame retardant (B) is uniformly dispersed by heating, pressurizing, or heat pressing in the presence of an organic peroxide. The polybutadiene resin composition of the present invention can be used as a resin composition for forming an insulating layer of a circuit board such as a printed circuit board. In particular, it can be suitably used as a resin composition for forming an insulating layer of a high-frequency circuit board by taking advantage of the advantage that an insulating layer having a low dielectric constant and a low dielectric tangent can be obtained. The polybutadiene resin composition of the present invention can be impregnated into various organic or inorganic materials of cross or non-woven fabrics and dried to be used as a prepreg which is a substrate material. Examples of the cross or non-woven fabric of inorganic materials include glass cloth or glass non-woven fabric. Further, by laminating the prepreg with a conductor foil such as a copper foil and performing heat pressing, a laminated board having a conductor foil on the surface can be produced. The temperature conditions during the heat pressing process are not particularly limited as long as they are conditions under which curing can be achieved by a heat-setting reaction in the prepreg based on the initiator. Such conditions are not particularly limited, but the temperature conditions are preferably 120 to 230°C, more preferably 140 to 210°C. The pressure conditions during the heat pressing process are not particularly limited as long as they are conditions for bonding the cured prepreg to the copper foil, but are preferably 10 to 80 kN, more preferably 20 to 70 kN.

Examples

[0045] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples at all. <Measurement of weight-average molecular weight> Regarding the polymer samples synthesized in Examples and the like, a molecular weight measurement column (TSKgel (registered trademark) SuperAW2500 + 3000 + 5000, manufactured by Tosoh Corporation) was connected to a gel permeation chromatography apparatus (HLC-8320GPC, manufactured by Tosoh Corporation), and measurement was performed under the detection conditions of a chloroform eluent at a flow rate of 0.6 mL / min, a temperature of 40°C, and UV (254 nm). Furthermore, using standard polystyrene, the weight-average molecular weight of the sample in terms of standard polystyrene was measured. Other matters were carried out in accordance with JIS-K-7252. <Measurement of weight loss temperature> As an index of the thermal stability of the halogen-containing polymer, the weight loss temperature was measured under the following conditions.

[0046] Analyzer: ThermoPlus TG8120 manufactured by Rigaku Corporation Measurement conditions: For 10 mg of the sample, heating was carried out in air at a rate of 10°C / min. <Synthesis of halogen-containing polymer> Synthesis Example 1 Into a 5 L glass cylindrical separable flask equipped with a stirrer and a reflux condenser, 800.0 g (1.471 mol) of tetrabromobisphenol A, 254.1 g (1.839 mol) of potassium carbonate, 4.00 g (26.6 mmol) of 4-tert-butylphenol, 4.01 g (6.19 mmol) of tris(2,4-di-tert-butylphenyl) phosphite, and 2100 g of dimethylformamide were charged, and the temperature was raised to 130°C while stirring and mixing. At this temperature, 186.3 g (1.883 mol) of dichloroethane was added, and after stirring at 130°C for 4 hours, it was allowed to cool to room temperature. Methanol was added to the reaction solution to precipitate a solid. The precipitated solid was filtered, washed with water, and then dried. A brominated flame retardant (a) in the form of a white solid was obtained with a yield of 90%.

[0047] The weight average molecular weight of the obtained brominated flame retardant (a) was 10,600, and the 5% weight loss temperature was 367 °C.

[0048] Synthesis Example 2 In Synthesis Example 1, the same procedure as in Synthesis Example 1 was carried out except that the amount of dichloroethane used was 218.3 g (2.206 mol), and a white solid brominated flame retardant (b) was obtained in a yield of 81%. The weight average molecular weight of the obtained brominated flame retardant (b) was 3,400, and the 5% weight loss temperature was 374 °C.

[0049] Synthesis Example 3 In Synthesis Example 1, the same procedure as in Synthesis Example 1 was carried out except that the amount of dichloroethane used was 175.6 g (1.775 mol), and a white solid brominated flame retardant (b) was obtained in a yield of 92%. The weight average molecular weight of the obtained brominated flame retardant (b) was 15,600, and the 5% weight loss temperature was 370 °C. <Evaluation of Dispersibility of Flame Retardant> The materials used for the evaluation are shown below. Brominated flame retardant (f): decabromodiphenylethane Brominated flame retardant (g): ethylene bis(tetrabromophthalimide) Organic peroxide: dicumyl peroxide Example 1 To 100 parts by weight of polybutadiene resin (B-3000 manufactured by Nippon Soda Co., Ltd.), 20 parts by weight of brominated flame retardant (a), 3 parts by weight of dicumyl peroxide, and 20 parts by weight of toluene were stirred and mixed with a magnetic stirrer to obtain a polybutadiene resin composition (A1).

[0050] Example 2 A polybutadiene resin composition (B1) was obtained in the same manner as in Example 1, except that brominated flame retardant (b) was used instead of brominated flame retardant (a).

[0051] Example 3 A polybutadiene resin composition (C) was obtained in the same manner as in Example 1, except that brominated flame retardant (c) was used instead of brominated flame retardant (a).

[0052] Example 4 A polybutadiene resin composition (D) was obtained in the same manner as in Example 1, except that 30 parts by weight of brominated flame retardant (a) was used instead of 20 parts by weight of brominated flame retardant (a).

[0053] Example 5 A polybutadiene resin composition (E) was obtained in the same manner as in Example 1, except that 35 parts by weight of toluene was used instead of 25 parts by weight of toluene.

[0054] Comparative Example 1 A polybutadiene resin composition (F) was obtained in the same manner as in Example 1, except that brominated flame retardant (f) was used instead of brominated flame retardant (a).

[0055] Comparative Example 2 A polybutadiene resin composition (G) was obtained in the same manner as in Example 1, except that brominated flame retardant (g) was used instead of brominated flame retardant (a).

[0056] After allowing the polybutadiene resin compositions obtained in the examples and comparative examples to stand for 24 hours, when no sedimentation of the brominated flame retardant was visually observed, the dispersibility was judged as "〇". When sedimentation of the brominated flame retardant was observed, the dispersibility was judged as "×". The results are shown in Table 1.

[0057]

Table 1

[0058] From the results in Table 1, it can be seen that the polybutadiene resin composition of the present invention is excellent in the dispersibility of the brominated flame retardant as compared with the conventional polybutadiene resin composition. <Evaluation of Dielectric Constant, Dissipation Factor, Coefficient of Linear Expansion of Cured Product, and Dispersibility of Flame Retardant> Examples 6 to 7, Comparative Example 2 First, 0.8 g of the polybutadiene resin composition (A1) was applied to a PTFE film and vacuum-dried overnight at room temperature in a vacuum oven. A gold frame (80 mm × 60 mm × 0.25 mm t) was placed on the PTFE film, and a hydraulic vacuum heating press machine, model IMC-11FD (manufactured by Imoto Seisakusho Co., Ltd.), was used to apply pressure and heat to obtain a cured product. The curing conditions were maintained at 150 °C, 60 kN for 30 minutes under atmospheric pressure. Subsequently, after releasing the pressure once, the temperature was raised, and it was maintained at 195 °C, 40 kN for 2 hours under reduced pressure to create a cured product.

[0059] Example 7 A cured product was created in the same manner as in Example 6, except that the polybutadiene resin composition (B1) was used instead of the polybutadiene resin composition (A1).

[0060] Comparative Example 3 A cured product was created in the same manner as in Example 6, except that the polybutadiene resin composition (F) was used instead of the polybutadiene resin composition (A1). 〈Measurement of Dielectric Constant and Dissipation Factor〉 For the created cured product, measurements were taken using a TE cavity resonator (manufactured by Keycom Co., Ltd.) under the condition of a frequency of 28 GHz. 〈Measurement of Coefficient of Linear Thermal Expansion〉 For the created cured product, measurements were performed using a TMA Q400EM (manufactured by TA Instruments) with a tensile probe under the conditions of a heating rate of 5 °C / min, a measurement temperature range from room temperature to 200 °C, and a load of 0.1 N. As the measurement method, the coefficient of linear thermal expansion from room temperature to 200 °C when the temperature was raised from room temperature to 200 °C and then cooled back to room temperature and raised to 200 °C again was designated as α. 〈Dispersibility of Flame Retardant〉 For the created cured product, when the flame retardant was visually determined to be uniformly dispersed, it was judged as "〇". When there was unevenness, it was judged as "×". The results are shown in Table 2.

[0061]

Table 2

[0062] From the results in Table 2, it can be seen that the polybutadiene resin composition of the present invention can obtain a cured product in which the flame retardant is substantially uniformly dispersed.

Claims

1. A polybutadiene resin composition comprising 5 to 100 parts by weight of a brominated flame retardant (B) represented by the following general formula (2) with respect to 100 parts by weight of a polybutadiene resin (A) having a number average molecular weight of 1,000 to 20,000 and having a repeating unit represented by the following general formula (1). 【Chemical 1】 【Chemical 2】 (In the formula, R represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO ２ -, and n represents an integer of 1 or more.)

2. The polybutadiene resin composition according to Claim 1, wherein the weight average molecular weight in terms of standard polystyrene measured by gel permeation chromatography of the brominated flame retardant (B) is 1,000 to 20,000.

3. The polybutadiene resin composition according to Claim 1 or Claim 2, wherein in the general formula (2), R is an alkylene group having 1 to 6 carbon atoms.

4. The polybutadiene resin composition according to Claim 1 or Claim 2, wherein in the general formula (2), R is a 2,2-propylene group.

5. The polybutadiene resin composition according to Claim 1 or Claim 2, which contains an organic peroxide.

6. A polybutadiene cured product formed from the resin composition according to Claim 1 or Claim 2.

7. A polybutadiene cured product containing polybutadiene and the brominated flame retardant (B) represented by the general formula (2), wherein the brominated flame retardant (B) is uniformly dispersed in the cured product.

8. A method for producing a polybutadiene cured product, comprising heating, pressurizing, or hot pressing the polybutadiene resin composition according to Claim 1 or Claim 2 in the presence of an organic peroxide.

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