JP7123464B2 - Novel crystalline form of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenyl sulfone and method for preparing same - Google Patents

Description

The present invention relates to a novel crystalline form of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenyl sulfone and a process for its preparation.

4,4'-Bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenyl sulfone is useful as a flame retardant for synthetic resins, typified by olefin resins and styrene resins. Resins containing these flame retardants are used in various applications, mainly in the electrical and electronic fields where flame retardancy is required.

4,4'-Bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenyl sulfone has traditionally been a low-melting (having a melting point around 45°C) amorphous solid. and a crystal with a medium melting point (having a melting point of 100° C. or higher and lower than 130° C., particularly around 110 to 125° C.) (hereinafter, the crystal with a medium melting point is referred to as “type I crystal”) has been reported (for example, patent References 1 to 4).

Amorphous solids with low melting points tend to fuse and solidify during hot summer months, making handling during transport, storage, and use extremely complicated. , there were practical problems such as melting and not achieving the purpose. In order to solve the problems of such low-melting amorphous solids, methods for producing medium-melting type I crystals have been developed and reported, but they all have problems of poor workability and economic efficiency. . In addition, as is clear from the fact that the melting point of the type I crystals reported varies, there is a problem in reproducibility, and the results are not practically satisfactory.

JP-A-2-286645 JP-A-10-218824 JP-A-10-251184 JP 2007-112747 A

The present invention solves the above problems and provides a high melting point 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenyl useful as a flame retardant for synthetic resins. A novel crystalline form of sulfone and a method for producing the same.

The present inventors have conducted various studies on 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenylsulfone, and as a result, It was found that a new crystal form with a high melting point (hereinafter referred to as "type II crystal") exists. This new crystalline form is obtained by a simple procedure of applying a shearing force to the existing medium-melting type I crystals.

That is, the present invention is as follows.
[1] Diffraction angle 2θ in powder X-ray diffraction pattern by Cu-Kα rays = 16.5°±0.3°, 19.9°±0.3°, 21.1°±0.3°, 22. 0°±0.3°, 22.5°±0.3°, 23.1°±0.3°, 24.1°±0.3°, 24.8°±0.3°, 26. 4,4′-bis(2,3-dibromopropoxy)-3,3′,5,5′-tetrabromodiphenyl with peaks at 3°±0.3° and 29.3°±0.3° A crystalline form of sulfone.
[2] The crystalline form according to [1], which has an endothermic peak at 125 to 135°C by differential scanning calorimetry.
[3] A crystal form of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenyl sulfone having an endothermic peak at 130 to 135°C by differential scanning calorimetry .
[4] An endothermic peak measured by differential scanning calorimetry at 100° C. or more and less than 130° C., and a diffraction angle 2θ=17.5°±0.3°, 27.6°± in a powder X-ray diffraction pattern using Cu—Kα rays. 4,4′-bis(2,3- Dibromopropoxy)-3,3′,5,5′-tetrabromodiphenylsulfone crystals are subjected to shearing force, and have an endothermic peak at 125 to 135° C. and a Cu—Kα ray according to differential scanning calorimetry. Diffraction angle 2θ = 16.5° ± 0.3°, 19.9° ± 0.3°, 24.1° ± 0.3°, 26.3° ± 0.3° and a crystalline form of 4,4′-bis(2,3-dibromopropoxy)-3,3′,5,5′-tetrabromodiphenyl sulfone having a peak at 29.3°±0.3° .
[5] A flame retardant comprising a crystalline form of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenylsulfone according to [1] to [3] .

The crystalline form of the present invention is a novel crystalline form of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenyl sulfone useful as a flame retardant. The crystalline form of the present invention is excellent in workability, economic efficiency and reproducibility because it can be produced by a simple operation reproducible on a commercial scale by applying a shearing force to an existing type I crystal. In addition, the novel crystal form (type II crystal) has a high melting point of 125° C. or higher, so it has excellent thermal stability, is advantageous for storage and transportation, and can be easily blended into various resins as a flame retardant.

Differential scanning calorimetry (DSC) curve of type I crystal of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenylsulfone obtained in Synthesis Example 1 It is a figure which shows. 4 shows a powder X-ray crystal diffraction pattern of type I crystals of 4,4′-bis(2,3-dibromopropoxy)-3,3′,5,5′-tetrabromodiphenylsulfone obtained in Synthesis Example 1. It is a diagram. 1 is a diagram showing a DSC curve of type II crystals of 4,4′-bis(2,3-dibromopropoxy)-3,3′,5,5′-tetrabromodiphenylsulfone obtained in Example 1. FIG. 4 shows a powder X-ray crystal diffraction pattern of type II crystals of 4,4′-bis(2,3-dibromopropoxy)-3,3′,5,5′-tetrabromodiphenylsulfone obtained in Example 1. It is a diagram. 1 is a diagram showing a DSC curve of type II crystals of 4,4′-bis(2,3-dibromopropoxy)-3,3′,5,5′-tetrabromodiphenylsulfone obtained in Example 2. FIG. 4 shows a powder X-ray crystal diffraction pattern of type II crystals of 4,4′-bis(2,3-dibromopropoxy)-3,3′,5,5′-tetrabromodiphenylsulfone obtained in Example 2. It is a diagram.

The present invention relates to a novel crystalline form of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenyl sulfone. Although there are several methods for characterizing crystalline forms, such as by differential scanning calorimetry (DSC) curves, powder X-ray crystal diffraction patterns, single crystal X-ray analysis, etc., the crystals of the present invention The crystal form was measured under the following conditions.

[Differential scanning calorimetry (DSC)]
Measuring instrument: DSC-60 (manufactured by Shimadzu Corporation)
Heating rate: 10°C/min

[Powder X-ray crystal diffraction]
Measuring instrument: XRD-7000 (manufactured by Shimadzu Corporation)
Scanning speed: 5.0°/min X-ray: Cu-Kα line Voltage: 50 kV
Current: 40mA
Scanning range: 5-65°
Sampling width: 0.02°

The novel crystal form (type II crystal) of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenyl sulfone in the present invention is shown in FIG. 4 or FIG. characterized by a powder X-ray crystal diffraction pattern. Characteristic peaks in the powder X-ray crystal diffraction pattern of the type II crystal include 2θ values of 16.5°±0.3°, 19.9°±0.3°, and 21.1°±0.3°. , 22.0°±0.3°, 22.5°±0.3°, 23.1°±0.3°, 24.1°±0.3°, 24.8°±0.3° , 26.3°±0.3° and 29.3°±0.3°. The allowable width (±0.3°) of the peak position is preferably ±0.2°. Among them, the characteristic peaks in the powder X-ray crystal diffraction pattern of the type II crystal are 16.5° ± 0.3°, 19.9° ± 0.3°, 24.1° and 24.1°. °±0.3°, 26.3°±0.3° and 29.3°±0.3°.

The novel crystal form (type II crystal) of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenyl sulfone in the present invention is also shown in FIG. Characterized by the DSC curve shown. Therefore, the type II crystal of the present invention has characteristic peaks in the above powder X-ray crystal diffraction pattern and exhibits an endothermic peak of 125 to 135°C, preferably 130 to 135°C by DSC.

The type II crystal of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenylsulfone in the present invention is an existing medium-melting crystal (type I crystal). It can be manufactured by applying a shear force.

The type I crystal of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenylsulfone in the present invention was determined by the powder X-ray crystal diffraction pattern shown in FIG. Characterized. Characteristic peaks in the powder X-ray crystal diffraction pattern of the type I crystal include 2θ values of 17.5°±0.3°, 21.4°±0.3°, and 22.3°±0.3°. , 23.0°±0.3°, 24.8°±0.3°, 27.6°±0.3°, 28.6°±0.3°, 30.5°±0.3° , 31.3°±0.3° and 34.1°±0.3°. The allowable width (±0.3°) of the peak position is preferably ±0.2°. Among them, the characteristic peaks in the powder X-ray crystal diffraction pattern of the type I crystal for the type II crystal are 17.5° ± 0.3°, 27.6° ± 0.3°, 30.5° °±0.3°, 31.3°±0.3° and 34.1°±0.3°.

The existing medium melting point crystal (type I crystal) of 4,4′-bis(2,3-dibromopropoxy)-3,3′,5,5′-tetrabromodiphenyl sulfone in the present invention is also shown in FIG. Characterized by the DSC curve shown. Therefore, the type I crystal to be subjected to the production method of the present invention has a characteristic peak in the above powder X-ray crystal diffraction pattern, and an endothermic peak by DSC of 100°C or higher and lower than 130°C, preferably 110°C. ~127°C.

4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenylsulfone in the present invention is not particularly limited, but for example, the production method described in the following synthesis scheme obtained by

In the above production method, each step of allylation of tetrabromobisphenol S and bromination of the allyl moiety can be performed without purification. By crystallizing the obtained target product according to the prior art document described above and Synthesis Example 1 described later, a type I crystal having a melting point of 100° C. or more and less than 130° C. can be obtained.

Specifically, the method for producing type II crystals of the present invention can be carried out by supplying type I crystals to a kneader, a stirring device, or the like and applying a shearing force. According to the present invention, high-melting type II crystals can be obtained in an extremely short time by applying a shearing force to type I crystals without requiring precipitation from a solvent or addition of seed crystals.

The shearing force applied to the type I crystal of the present invention is not particularly limited, but in consideration of economic efficiency, it is 1 kW·s/kg or more, preferably 10 kW·s/kg or more, relative to 1 kg of the type I crystal. more preferably 20 kW·s/kg or more, most preferably 30 kW·s/kg or more. The shear force can be calculated using the following formula.

The residence time is determined by the magnitude of the applied shearing force, the type or capacity of the device, etc., but is usually within 1 hour.

Devices for applying a shearing force include, for example, a wheel type kneader such as a speed muller; a ball type kneader such as a ball mill; a paddle type (single shaft, double shaft), a screw type (single shaft, double shaft), a rotor type ( Single-screw, double-screw), self-cleaning type, double-arm type (open type, pressurized type), etc. Blade type kneaders (Nekka machine, extruder); Roll mixers, taper rolls, Banbury, continuous rolls, etc. type kneaders; high shearing force stirring devices such as helical ribbon blades and wide paddle blades; line stirring devices such as multi-shaft stirring devices and static mixers.

The operating method is a batch system, a semi-batch system, a continuous system, or the like. The operating temperature is between 40 and 100°C, preferably between 60 and 100°C. The operating temperature need not be held constant and may vary between 40 and 100°C. By pulverizing the obtained type II crystals, type II crystals of a powder or granules having an arbitrary particle size and shape can be obtained.

Type II crystals of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenyl sulfone have a high melting point of 125°C or higher, and thus have excellent thermal stability. , is useful as a flame retardant. In the present invention, the term "flame retardant" refers to those used for the purpose of imparting properties such as flame retardancy and non-flammability to combustible materials such as plastics, rubbers, fibers, and wood. The present invention therefore also relates to flame retardants comprising type II crystals of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenyl sulfone. Here, the type II crystals of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenylsulfone may include type II crystals. Specifically, the ratio of type II crystals to all 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenylsulfone crystals contained in the flame retardant On the other hand, it is preferably 30% by mass or more, more preferably 50% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass or more. The flame retardant of the present invention can be easily blended into various resins such as thermoplastic resins, thermosetting resins and thermoplastic elastomers. Among them, polyolefins such as polyethylene and polypropylene; vinyl resins such as vinyl acetate resin and vinyl chloride resin; and styrene resins such as polystyrene, high impact polystyrene and ABS (acrylonitrile-butadiene-styrene copolymer) are effective.

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

In the examples, each crystal was analyzed under the following conditions.
[Differential scanning calorimetry (DSC)]
Measuring instrument: DSC-60 (manufactured by Shimadzu Corporation)
Heating rate: 10°C/min

[Powder X-ray crystal diffraction]
Measuring instrument: XRD-7000 (manufactured by Shimadzu Corporation)
Scanning speed: 5.0°/min X-ray: Cu-Kα line Voltage: 50 kV
Current: 40mA
Scanning range: 5-65°
Sampling width: 0.02°

Synthesis example 1
Acetone is added to 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenyl sulfone with a melting point (endothermic peak by differential scanning calorimetry) of 46°C and dissolved by heating. After that, it was cooled to obtain crystals (type I crystal, HPLC purity: 99%). The results of differential scanning calorimetry of the obtained crystals are shown in FIG. Its melting point (endothermic peak by differential scanning calorimetry) was 127°C. 2 and Table 1 show the powder X-ray crystal diffraction pattern of the obtained crystals.

Example 1
4,4′-bis(2,3-dibromopropoxy)-3,3′ obtained in Synthesis Example 1 was placed in a 120 cc small twin-screw continuous kneader (S1KRC kneader manufactured by Kurimoto, Ltd.). ,5,5′-Tetrabromodiphenylsulfone was continuously supplied at a rate of 6.7 kg/hr, and the content was continuously discharged from the kneader outlet, cooled and pulverized to obtain crystals (type II crystals ). During operation, the operating temperature was 100° C., the rotation speed was 300 rpm, the residence time was 40 seconds, and the applied shear force was 40 kW·s/kg. FIG. 3 shows the results of differential scanning calorimetry of the obtained crystals. Its melting point (endothermic peak by differential scanning calorimetry) was 133°C. FIG. 4 and Table 2 show the powder X-ray crystal diffraction pattern of the obtained crystals.

Example 2
BAE-400S (Manac Co., Ltd., melting point (endothermic peak by differential scanning calorimetry) 113 ° C.) was added to a 120 cc small twin-screw continuous kneader (Kurimoto, Ltd., S1KRC kneader). While continuously supplying at a rate of .7 kg/hr, the content was continuously discharged from the kneader outlet, cooled and pulverized to obtain crystals (II type crystals). The operating temperature during operation was 100° C., the rotation speed was 300 rpm, the residence time was 40 seconds, and the applied shear force was 25 kW·s/kg. FIG. 5 shows the results of differential scanning calorimetry of the obtained crystals. Its melting point (endothermic peak by differential scanning calorimetry) was 125°C. 6 and Table 3 show the powder X-ray crystal diffraction pattern of the obtained crystals.

The novel crystal form (type II crystal) of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenyl sulfone of the present invention is an existing crystal with a medium melting point ( It can be produced by applying a shearing force to the type I crystal). According to the production method of the present invention, a novel crystal form (type II crystal) having a high melting point of 125° C. or higher can be produced with good reproducibility and efficiency. In addition, the new crystal form (type II crystal) has excellent thermal stability, is advantageous for storage and transportation, and is also excellent in operability. Therefore, it becomes easy to mix with various resins as a flame retardant.

Claims (5)

The diffraction angle 2θ in the powder X-ray diffraction pattern by Cu-Kα rays is 16.5° ± 0.3°, 19.9° ± 0.3°, 21.1° ± 0.3°, 22.0° ±0.3°, 22.5°±0.3°, 23.1°±0.3°, 24.1°±0.3°, 24.8°±0.3°, 26.3° 4,4'-Bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenyl sulfone with peaks at ±0.3° and 29.3° ±0.3° crystal. The crystal according to claim 1, which has an endothermic peak at 125 to 135°C by differential scanning calorimetry. A crystal of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenylsulfone having an endothermic peak at 130-135°C by differential scanning calorimetry. It has an endothermic peak at 100° C. or more and less than 130° C. by differential scanning calorimetry, and diffraction angles 2θ in a powder X-ray diffraction pattern by Cu—Kα rays are 17.5°±0.3° and 27.6°±0. 4,4′-bis(2,3-dibromopropoxy )-3,3′,5,5′-Tetrabromodiphenylsulfone crystals are subjected to a shearing force, which has an endothermic peak at 125 to 135° C. by differential scanning calorimetry and a powder by Cu—Kα radiation. The diffraction angle 2θ in the X-ray diffraction pattern is 16.5° ± 0.3°, 19.9° ± 0.3°, 24.1° ± 0.3°, 26.3° ± 0.3° and A method for producing crystals of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenylsulfone having a peak at 29.3°±0.3°. A flame retardant comprising the crystals of 4,4'-bis(2,3-dibromopropoxy)-3,3',5,5'-tetrabromodiphenylsulfone according to any one of claims 1 to 3.

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