Brominated polyphenylene sulfide and its manufacturing method

Abstract

To provide a flame retardant which does not inhibit hue inherent in a resin, and exhibits a high flame retardant effect.SOLUTION: A brominated polyphenylene sulfide is represented by the following general formula (1), in the general formula (1), R represents a terminal group, and represents a hydrogen atom or a bromine atom; n represents the number of bromine atoms bonded to a terminal benzene ring, and represents a real number of 1-5; m represents the number of bromine atoms bonded to a benzene ring, and represents a real number of 1-4; and p represents a repeated number, and represents a real number of 2 or more, in which a degree (W) of whiteness calculated by expression: W=100-{(100-L)2+(a2+b2)}1 / 2 from an Lab value of the brominated polyphenylene sulfide in a solid state at room temperature is 70 or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a brominated polyphenylene sulfide having high whiteness and used as a flame retardant, etc., and a method for producing the same. [Background technology]

[0002] Generally, thermoplastic resins such as polyolefin resin, polystyrene resin, ABS resin, epoxy resin, polyester resin, acrylic resin, polycarbonate resin, polyamide resin, and polyacetal resin, and thermosetting resins such as phenolic resin, polyurethane resin, and melamine resin are not only lightweight and easy to mold, but also have excellent properties depending on the resin type, and are therefore used in a variety of applications including building materials, electrical equipment materials, household goods, and automotive materials.

[0003] However, these resins generally have the drawback of being easily flammable, and for their use in applications where there is a risk of combustion, it is essential to make the resin flame-retardant. A common method of making resin flame-retardant is to mix a flame retardant into the resin, but it is known that a high flame-retardant effect can be obtained with a small amount of addition, especially when mixing a brominated flame retardant with a flame-retardant assistant agent such as antimony oxide.

[0004] Examples of brominated flame retardants include brominated polystyrene (Patent Document 1 and Patent Document 2), decabromodiphenyl ether (Patent Document 3), brominated styrene-maleic anhydride polymer (Patent Document 4), brominated crosslinked aromatic polymer (Patent Document 5), and brominated sulfide compound (Patent Document 6). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 51-47044 [Patent Document 2] Japanese Patent Application Publication No. 4-175371 [Patent Document 3] Japanese Patent Application Publication No. 47-7134 [Patent Document 4] Japanese Patent Application Publication No. 3-168246 [Patent Document 5] Japanese Patent Publication No. 63-317552 [Patent Document 6] U.S. Patent No. 4,619,961 Summary of the Invention [Problem to be solved by the invention]

[0006] Resins used in home appliances and the like are required to be white, and therefore the flame retardants blended to make the resins flame-retardant are also required to be white. However, the brominated polyphenylene sulfide disclosed in Patent Document 6 has a problem in that it is brown in color and therefore cannot be used in applications where white color is required or where color changes are undesirable. [Means for solving the problem]

[0007] As a result of intensive investigations conducted by the present inventors to solve the above-mentioned problems, they have found that brominated polyphenylene sulfide with an unprecedented high degree of whiteness can be obtained by performing the following procedure in the post-treatment of the bromination reaction of polyphenylene sulfide: distilling off unreacted bromine in the presence of a halogen-containing aromatic hydrocarbon solvent such as o-dichlorobenzene; and then adding a substance that reduces bromine or a substance that readily reacts with bromine to the resulting reaction solution to remove the residual bromine, thereby completing the present invention.

[0008] That is, the present invention relates to the following brominated polyphenylene sulfide.

[0009] [1] The following general formula (1)

[0010] [ka]

[0011] (In the formula, R represents a terminal group and represents a hydrogen atom or a bromine atom. n represents the number of bromine atoms bonded to the terminal benzene ring and represents a real number of 1 to 5. m represents the number of bromine atoms bonded to the benzene ring and represents a real number of 1 to 4. p represents the number of repetitions and represents a real number of 2 or more.) The brominated polyphenylene sulfide is represented by the following formula: W=100-{(100-L)} 2 +(a 2 +b 2 )} 1 / 2 A brominated polyphenylene sulfide characterized by having a whiteness (W) of 70 or more as calculated by the above method.

[0012] [2] The brominated polyphenylene sulfide represented by the general formula (1) is represented by the following general formula (2):

[0013] [ka]

[0014] (wherein R, n, m, and p are defined as in the general formula (1) above),

[0015] [3] The brominated polyphenylene sulfide according to [1] or [2], characterized in that the 10 wt % heat weight loss temperature is 330°C or higher.

[0016] [4] The brominated polyphenylene sulfide according to any one of [1] to [3], characterized in that the bromine content is 30 to 65% by weight.

[0017] [5] The brominated polyphenylene sulfide according to any one of [1] to [4], characterized in that the yellowness index (YI) calculated in accordance with ASTM E313 is 50 or less.

[0018] [6] The brominated polyphenylene sulfide according to any one of [1] to [5], wherein p is a real number greater than 50 and equal to or less than 300.

[0019] [7] A method for producing brominated polyphenylene sulfide according to any one of [1] to [6], comprising the following steps (1) to (4):

[0020] Step (1): Mixing polyphenylene sulfide and bromine and heating to brominate the polyphenylene sulfide. Step (2): After the step (1), the unreacted bromine in the reaction solution obtained in step (1) is removed by distillation in a state where the halogen-containing aromatic hydrocarbon solvent coexists in the reaction solution. Step (3): A step of adding a substance that reduces bromine or a substance that easily reacts with bromine to the reaction liquid remaining after the step (2) to obtain a slurry containing a solid of brominated polyphenylene sulfide. Step (4): A step of separating the solid (brominated polyphenylene sulfide) from the slurry obtained in the step (3) and washing the solid with a solvent. [Effects of the Invention]

[0021] The brominated polyphenylene sulfide of the present invention has a higher whiteness than conventionally known brominated polyphenylene sulfides obtained by conventionally known production methods, and can be safely used as a flame retardant for white resins. Therefore, the brominated polyphenylene sulfide of the present invention is expected to be used as a highly versatile flame retardant, particularly in fields where the appearance of resins is important, such as home appliances and automotive interior materials. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention will be described in more detail below.

[0023] The present invention relates to a compound represented by the following general formula (1):

[0024] [ka]

[0025] (In the formula, R represents a terminal group and represents a hydrogen atom or a bromine atom. n represents the number of bromine atoms bonded to the terminal benzene ring and represents a real number of 1 to 5. m represents the number of bromine atoms bonded to the benzene ring and represents a real number of 1 to 4. p represents the number of repetitions and represents a real number of 2 or more.) The brominated polyphenylene sulfide is represented by the following formula: W=100-{(100-L)} 2 +(a 2 +b 2 )} 1 / 2 The present invention relates to a brominated polyphenylene sulfide characterized in that the whiteness (W) calculated by the above formula is 70 or more.

[0026] Regarding the brominated polyphenylene sulfide represented by the above general formula (1), in terms of ease of production,

[0027] [ka]

[0028] (In the formula, R, n, m, and p are defined as in the general formula (1) above.) It is preferable that the brominated polyphenylene sulfide is a brominated polyphenylene sulfide represented by the following formula:

[0029] In the above general formulas (1) and (2), n and m represent the number of bromine atoms bonded to the benzene ring and are real numbers from 1 to 5 and 1 to 4, respectively. The above brominated polyphenylene sulfide may be a single compound or a mixture of multiple compounds, but is usually formed as a mixture of multiple compounds. Therefore, when the brominated polyphenylene sulfide is a single compound, n and m in the general formulas (1) and (2) are represented by integers, and when the brominated polyphenylene sulfide is a mixture of multiple compounds, n and m in the general formulas (1) and (2) are represented by average values, i.e., real numbers. For the brominated polyphenylene sulfide represented by the general formula (1), the larger the values ​​of n and m, i.e., the higher the bromine atom content, the more improved performance as a flame retardant is expected.

[0030] The bromine content (wt%) of the brominated polyphenylene sulfide of the present invention can be determined by combustion-ion chromatography, although this is not particularly limited. Specific analytical methods and conditions for combustion-ion chromatography are described in IEC 62321-3-2.

[0031] The bromine content is preferably in the range of 30 to 65% by weight, more preferably 45 to 65% by weight, and even more preferably 55 to 65% by weight, in terms of excellent flame retardancy. The bromine content is usually estimated as an average value determined by measuring a mixture of multiple polymers with different n and m. Therefore, it is possible to estimate the average values ​​of n and m in the polymer mixture from the bromine content. When the bromine content of the brominated polyphenylene sulfide is 43 wt%, m = n = 1 (average value, R represents a hydrogen atom); when the bromine content of the brominated polyphenylene sulfide is 52 wt%, m = n = 1.5 (average value, R represents a hydrogen atom); when the bromine content of the brominated polyphenylene sulfide is 59 wt%, m = n = 2 (average value, R represents a hydrogen atom); and when the bromine content of the brominated polyphenylene sulfide is 69 wt%, m = n = 3 (average value, R represents a hydrogen atom). The average values ​​of n and m are preferably real numbers of 1 to 4, more preferably real numbers of 1.2 to 3, and even more preferably real numbers of 1.5 to 2.5. R is preferably a hydrogen atom.

[0032] In the above general formulas (1) and (2), p represents the average number of repeating units and is a real number of 2 or more. The value of p can be determined from the bromine content and the molecular weight of the polymer. The molecular weight of the brominated polyphenylene sulfide represented by the above general formula (1) or (2) is usually measured as the average molecular weight of a mixture of multiple polymers. When calculating the number of repeating units using such an average molecular weight, p is calculated as an average value (real number). In terms of excellent heat resistance, p is preferably a real number of 2 to 300, more preferably a real number greater than 50 but not exceeding 300, more preferably a real number of 55 to 200, and even more preferably a real number of 60 to 150.

[0033] The average molecular weight of the brominated polyphenylene sulfide represented by general formula (1) or (2) can be determined using a general molecular weight measurement method, and examples of the method include, but are not limited to, a method using gel permeation chromatography, a method using solution viscosity, or mass spectrometry (e.g., MALDI-TOF-MS analysis).

[0034] The average molecular weight of the brominated polyphenylene sulfide of the present invention is preferably 8,000 to 50,000, more preferably 10,000 to 30,000, and even more preferably 12,000 to 20,000. The average molecular weight is preferably that analyzed by MALDI-TOF-MS analysis, and more preferably the peak top value of the analytical value analyzed by MALDI-TOF-MS analysis.

[0035] Furthermore, the brominated polyphenylene sulfide of the present invention preferably does not substantially contain soluble components having a retention factor of 2.0 or more as detected by high-performance liquid chromatography using an octadecylsilyl column (ODS column). Specifically, "substantially does not contain" means that the peak area having a retention factor of 2.0 or more as detected by high-performance liquid chromatography using an ODS column is less than 1% of the total peak area of ​​soluble components as detected by high-performance liquid chromatography, preferably less than 0.5%, more preferably less than 0.2%, and even more preferably below the detection limit.

[0036] The soluble compounds detected by high-performance liquid chromatography using the above-mentioned ODS column and observed to have a retention coefficient of 2.0 or more are by-products in the bromination process of polyphenylene sulfide, and are brown in color, causing a deterioration in the color tone and a decrease in heat resistance of the brominated polyphenylene sulfide.

[0037] The above soluble components were obtained and measured by high performance liquid chromatography using an ODS column according to the following procedure.

[0038] A 1 g sample of brominated polyphenylene sulfide prepared by the method described in the Examples was placed in a cylindrical filter and placed in a Soxhlet extractor. Next, 60 mL of acetone was added and refluxed at 160°C for 140 minutes to obtain an extract of the soluble components contained in the brominated polyphenylene sulfide. The extract was dried by blowing nitrogen over it, then redissolved in 2 mL of a 1:1 methanol / tetrahydrofuran solution and further diluted 10-fold to prepare the test solution. If insoluble components precipitated during redissolution, the solution was filtered.

[0039] A Tosoh TSKgel ODS-100V (5 μm, 4.6 mm ID × 25 cm) column was connected to a Waters Acquity UPLC H-Class. Using methanol / tetrahydrofuran (99:1) as the eluent, 10 μL of the test solution was injected at a flow rate of 1.0 mL / min and a column temperature of 40°C. The analytical results were detected using a PDA (420 nm) detector.

[0040] As described in Patent Document 6, it was known that the bromination reaction of polyphenylene sulfide is prone to decomposition of the polyphenylene sulfide chain, resulting in discoloration of the brominated polyphenylene sulfide and reduced heat resistance. The inventors of the present invention improved conventional production methods to discover bromination reaction conditions that suppress decomposition of the polyphenylene sulfide chain, thereby completing the present invention. The brominated polyphenylene sulfide of the present invention, obtained under the reaction conditions discovered in the present invention, has the advantages of being able to suppress discoloration of the flame-retarded resin to a minimum, having a large molecular weight, and / or excellent heat resistance, compared to the brominated polyphenylene sulfide disclosed in Patent Document 6.

[0041] The brominated polyphenylene sulfide of the present invention is characterized by a whiteness (W value) of 70 or more as measured by a colorimeter (e.g., ZE-6000 manufactured by Nippon Denshoku). From the viewpoint of excellent retention of the original color tone of the resin when compounded, the whiteness (W value) is preferably 72 to 98, and more preferably 75 to 95. The whiteness (W value) can be calculated using the Lab value measured by the colorimeter according to the following formula: where a represents the degree of red to green, b represents the degree of yellow to blue, and L represents the degree of white to black. The whiteness obtained by this measurement method is generally known as the Hunter whiteness. The whiteness was measured according to the manual for the colorimeter.

[0042] W=100-{(100-L) 2 +(a 2 +b 2 )} 1 / 2 For the colorimeter, the power to the differential meter was turned on and allowed to stabilize for 30 minutes. After that, a projector lens (30 mm diameter) and a sample stage (30 mm diameter) were attached and standardization was performed. Next, 2.0 g of sample was weighed into the cell, and a 1 kg weight was placed on it for 30 seconds. At this time, it was confirmed that there were no spaces or wrinkles at the bottom of the cell, and then measurements were performed.

[0043] As described above, the brominated polyphenylene sulfide of the present invention is characterized by excellent whiteness, and further, it is preferable that the yellowness index (YI) measured using the same colorimeter as above and calculated in accordance with ASTM E313 has a low value, and in terms of excellent maintenance of the original color tone of the resin when compounded, it is preferably 50 or less, more preferably 45 or less, and even more preferably 40 or less. The yellowness index was also measured according to the manual for the colorimeter.

[0044] The brominated polyphenylene sulfide of the present invention has the advantage of being superior in whiteness compared to conventionally known brominated polyphenylene sulfides, as well as a high 10 wt % heat weight loss temperature. Specifically, the 10 wt % heat weight loss temperature is preferably 330°C or higher, more preferably 340°C or higher, and even more preferably 350°C or higher. The high 10 wt % heat weight loss temperature indicates that the brominated polyphenylene sulfide of the present invention is less susceptible to thermal decomposition at high temperatures and has high heat resistance.

[0045] The 10% thermal weight loss temperature was measured using a differential heating / thermogravimetric simultaneous analyzer (Rigaku ThermoPlus TG8120) or a thermogravimetric / calorimetric simultaneous analyzer, using an aluminum container and approximately 10 mg of sample in an air atmosphere at 10°C / min. The measurement was performed in accordance with the differential heating / thermogravimetric simultaneous analyzer manual and JIS K 7120-1987.

[0046] Furthermore, the brominated polyphenylene sulfide of the present invention preferably has a high melting point in terms of excellent heat resistance. For example, the melting point is preferably higher than 330°C, more preferably 340°C or higher, and even more preferably 340°C or higher, at which point decomposition proceeds before melting and the melting point cannot be measured.

[0047] The melting point was measured using a differential thermal-thermogravimetric simultaneous analyzer (Rigaku ThermoPlus TG8120), and the temperature at which a change corresponding to the melting of brominated polyphenylene sulfide was observed in the DTA curve was taken as the melting point.

[0048] The brominated polyphenylene sulfide of the present invention represented by general formula (1) or (2) can be produced by reacting the raw material polymer, polyphenylene sulfide, with bromine. However, if a conventionally known production method is used as is, soluble components with a retention factor of 2.0 or more as detected by high-performance liquid chromatography using an ODS column are generated, resulting in a brominated polyphenylene sulfide with poor whiteness (W value). This is presumably due to decomposition of the polyphenylene sulfide polymer chain. The present inventors have discovered that by improving the conventionally known production method, a brominated polyphenylene sulfide with a low content of the soluble components and high whiteness (W value) can be obtained. More specifically, the brominated polyphenylene sulfide of the present invention represented by general formula (1) or (2) can be produced by the following steps. Step (1): mixing polyphenylene sulfide and bromine and heating the mixture to brominate the polyphenylene sulfide; Step (2): After the step (1), a step of removing unreacted bromine from the reaction solution obtained in the step (1) by distillation in the presence of a halogen-containing aromatic hydrocarbon solvent (e.g., o-dichlorobenzene); Step (3): adding a substance that reduces bromine or a substance that readily reacts with bromine to the reaction liquid remaining after the step (2) to obtain a slurry containing a solid of brominated polyphenylene sulfide; Step (4): A step of separating a solid (brominated polyphenylene sulfide) from the slurry obtained in the step (3) and washing the solid with a solvent; The manufacturing method will be described in more detail below.

[0049] The polyphenylene sulfide (raw material) may be either a crosslinked type or a linear type, but it is preferable to use a linear type from the viewpoint that the bromine content of the product brominated polyphenylene sulfide can be increased and coloration can be reduced.

[0050] The average molecular weight of the polyphenylene sulfide (raw material) is not particularly limited, but from the viewpoints of compatibility with resins and heat resistance, it is preferably 2000 or more (18 or more repeating units), more preferably 5000 or more (45 or more repeating units), and even more preferably 10,000 or more (90 or more repeating units).

[0051] The bromination of polyphenylene sulfide can be carried out in the presence or absence of a catalyst. The catalyst is not particularly limited, but examples thereof include aluminum trichloride, iron trichloride, and iron tribromide, with aluminum trichloride being particularly preferred. Bromination in the absence of a catalyst is preferred because the resulting brominated polyphenylene sulfide has excellent whiteness.

[0052] Bromine may be used as it is, or may be used as a bromine solution in which bromine is dissolved in a solvent. Note that using bromine as it is is preferred in terms of excellent production efficiency of the brominated polyphenylene sulfide of the present invention.

[0053] The solvent for dissolving bromine is not particularly limited, but examples thereof include dichloromethane, 1,2-dichloroethane, 1,1,2-trichloroethane, chloroform, chlorobenzene, 1,2-dichlorobenzene, and 1,2,4-trichlorobenzene. Of these, chlorobenzene, 1,2-dichlorobenzene, and 1,2,4-trichlorobenzene are preferred in terms of suppressing decomposition of the polymer chain of polyphenylene sulfide.

[0054] Polyphenylene sulfide is a solid substance at room temperature. When carrying out a bromination reaction of polyphenylene sulfide, the solid polyphenylene sulfide can be used as is, or a solution in which polyphenylene sulfide is dissolved in a solvent can be used, or a slurry in which polyphenylene sulfide is dispersed in a solvent can be used.

[0055] The solvent for dissolving or dispersing the bromine and polyphenylene sulfide is not particularly limited, but examples thereof include dichloromethane, 1,2-dichloroethane, 1,1,2-trichloroethane, chloroform, chlorobenzene, 1,2-dichlorobenzene, and 1,2,4-trichlorobenzene. Of these, chlorobenzene, 1,2-dichlorobenzene, and 1,2,4-trichlorobenzene are preferred in terms of suppressing decomposition of the polymer chain of polyphenylene sulfide.

[0056] The reaction of polyphenylene sulfide with bromine can be carried out by adding, pouring, or dropping the polyphenylene sulfide solid, the polyphenylene sulfide solution, or the polyphenylene sulfide slurry into the bromine or the bromine solution.

[0057] The addition, pouring, or dropwise addition of polyphenylene sulfide, a polyphenylene sulfide solution, or a polyphenylene sulfide slurry to bromine or a bromine solution is preferably carried out under low-temperature conditions, with the temperature preferably being 0°C to 15°C. At this time, the addition, pouring, or dropwise addition is preferably carried out while stirring and mixing the reaction liquid. The aging reaction after the addition, pouring, or dropwise addition is carried out under heated conditions, with the temperature preferably being 25°C to 60°C, and more preferably being 50°C to 60°C. At this time, it is also preferable to continue stirring and mixing the reaction liquid.

[0058] The bromine content of the target brominated polyphenylene sulfide can be adjusted by adding additional bromine during the aging reaction. When adding bromine, bromine itself can be added, or bromine can be added in the form of a bromine solution dissolved in the above-mentioned solvent. Adding bromine itself is preferred because it provides excellent production efficiency for the brominated polyphenylene sulfide of the present invention.

[0059] The post-reaction treatment (corresponding to the above steps (2) and (3)) aims to remove unreacted bromine and trace amounts of residual bromine.

[0060] The above step (2) represents a step of removing unreacted bromine from the reaction solution obtained in the step (1) by distillation in a state in which the halogen-containing aromatic hydrocarbon solvent coexists in the reaction solution after the step (1).

[0061] In the above step (2), the halogen-containing aromatic hydrocarbon solvent is not particularly limited, but examples thereof include chlorobenzene, 1,2-dichlorobenzene, and 1,2,4-trichlorobenzene.

[0062] The halogen-containing aromatic solvent may be present in the reaction solution obtained in step (1) when unreacted bromine in the reaction solution is removed by distillation. The method for forming the coexistence state is not particularly limited, and examples thereof include a method of adding the halogen-containing aromatic solvent to the reaction solution obtained in step (1) immediately before the distillation operation, a method of adding the halogen-containing aromatic solvent at the time of reaction charging in step (1) or during the bromination reaction in step (1), and a method of adding the halogen-containing aromatic solvent to the reaction solution obtained by carrying out step (1).

[0063] The method of distillation is not particularly limited, but examples thereof include distillation by heating distillation, distillation by reduced pressure distillation, and distillation by nitrogen bubbling, and these may be combined.

[0064] Although most of the unreacted bromine can be removed by distillation in this manner, trace amounts of bromine may still remain in the reaction system. To further remove the trace amounts of residual bromine, it is preferable to add a substance that reduces bromine or a substance that readily reacts with bromine for treatment. For this reason, the above-mentioned step (3) is carried out.

[0065] Step (3) represents a step of adding a substance that reduces bromine or a substance that readily reacts with bromine to the reaction liquid remaining after step (2) to obtain a slurry containing a solid of brominated polyphenylene sulfide.

[0066] The substance (reducing agent) that reduces bromine is not particularly limited, but examples thereof include sodium sulfite, sodium hydrogen sulfite, sodium nitrite, sodium hydrogen nitrite, sodium thiosulfate, and hydrazine hydrate.

[0067] The bromine-reducing substance can be added to the reaction solution either directly or in the form of an aqueous solution in which it is dissolved in water. Addition as an aqueous solution is preferred in that a brominated polyphenylene sulfide with high whiteness can be obtained.

[0068] The substance that readily reacts with bromine is not particularly limited, but may include, for example, acetone.

[0069] By adding the above-mentioned substance to the reaction solution obtained in step (2), a slurry containing solid brominated polyphenylene sulfide can be obtained. At this time, bromine is reduced to produce hydrobromic acid. It is preferable to react the bromate with an inorganic base to convert it into a neutral bromide salt.

[0070] The inorganic base is not particularly limited, but examples thereof include sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium hydrogen carbonate. Of these, sodium hydroxide is preferred.

[0071] The produced bromide salt can be easily separated from the brominated polyphenylene sulfide by washing with water, which is not particularly limited, but may be, for example, the washing in step (4) described below.

[0072] Regarding the removal of trace amounts of residual bromine using the reducing agent, it is preferable to add a substance that reduces bromine or a substance that readily reacts with bromine to the residue from which bromine has been removed by distillation, to react with the trace amounts of bromine to produce hydrobromic acid, and then add an inorganic base to make the solution basic (by making the solution basic, the hydrobromic acid is neutralized and a bromide salt compound is produced).

[0073] The conditions in the above steps (2) and (3), such as the amount of halogen-containing aromatic hydrocarbon solvent added, the distillation conditions, the reaction conditions, and the concentration conditions in the aqueous solution of the substance that reduces bromine or the substance that readily reacts with bromine, are not particularly limited and can be arbitrarily selected within the scope of common sense of a person skilled in the art.

[0074] Brominated polyphenylene sulfide with high whiteness can be produced by separating and washing the solid (brominated) from the slurry obtained in the above step (3).

[0075] That is, the step (4) represents a step of separating a solid (brominated polyphenylene sulfide) from the slurry obtained in the step (3) and washing the solid with a solvent.

[0076] When separating the solid from the slurry, a generally known method can be used as the separation method, and although there are no particular limitations, examples thereof include filtration with a filter and centrifugation.

[0077] Furthermore, the method for washing the solid separated from the slurry with a solvent can be a generally known method, and is not particularly limited. For example, a method in which the solid is dispersed in a solvent and stirred, and then the solvent is removed by filtration can be used.

[0078] The solvent is not particularly limited, but examples thereof include water and organic solvent washing (alcohol washing, acetone washing). In the washing operation, any one of these solvents may be used alone or in combination. The washing operation may be performed once or multiple times. When washing is performed multiple times, the same solvent may be used, or different solvents may be used.

[0079] The brominated polyphenylene sulfide of the present invention can be produced by carrying out the above steps (1) to (4). The brominated polyphenylene sulfide of the present invention has the advantage of being significantly superior in whiteness compared to brominated polyphenylene sulfide produced by conventional methods. This advantage is believed to be due to the suppression of the decomposition reaction of brominated polyphenylene sulfide by the improvement of the above production method.

[0080] Furthermore, the brominated polyphenylene sulfide of the present invention has the advantages of a higher molecular weight, a smaller rate of weight loss on heating (a higher 10% weight loss temperature on heating), and excellent heat resistance compared to conventional brominated polyphenylene sulfides. These advantages are believed to be obtained by the above-described production method of the present invention.

[0081] The brominated polyphenylene sulfide of the present invention can impart flame retardancy to a resin by mixing it with the resin.

[0082] The resin is not particularly limited, but examples thereof include thermoplastic resins or thermosetting resins such as polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl acetate, polyvinyl vinyl acetate, polyurethane, acrylonitrile butadiene styrene resin, acrylic resin, phenolic resin, epoxy resin, melamine resin, urea resin, polyester resin, alkyd resin, polyurethane, polyurea, polyimide, polyamide, polyacetal, polycarbonate, modified polyphenylene ether, polyethylene terephthalate, polybutylene terephthalate, cyclic polyolefin, polyphenylene sulfide, polytetrafluoroethylene, polysulfone, polyethersulfone, polyetheretherketone, polyimide, and polyimideimide.

[0083] The blending ratio of the brominated polyphenylene sulfide to the resin is not particularly limited, but an example is 5 to 200 parts by weight of brominated polyphenylene sulfide per 100 parts by weight of the resin. In terms of excellent flame retardancy and maintenance of resin properties, the blending ratio is preferably 10 to 150 parts by weight, and more preferably 20 to 100 parts by weight.

[0084] When blending the brominated polyphenylene sulfide of the present invention with the resin, other additives may be added separately depending on the desired physical properties. The additives are not particularly limited, but examples thereof include antioxidants, light stabilizers, antistatic agents, ultraviolet absorbers, lubricants, plasticizers, flame retardants other than the brominated polyphenylene sulfide of the present invention, flame retardant auxiliaries, colorants, fillers, and foaming agents. [Brief explanation of the drawings]

[0085] [Figure 1] The chart obtained by MALDI-TOFMS analysis of the brominated polyphenylene sulfide synthesized in Example 1 is shown. [Figure 2] 1 is an analytical chart (detection wavelength: 420 nm) of the soluble components obtained in Comparative Example 1, obtained by high performance liquid chromatography using an ODS column. [Figure 3] 1 is an analytical chart (detection wavelength: 420 nm) of the soluble components obtained in Example 1, obtained by high performance liquid chromatography using an ODS column. [Explanation of symbols]

[0086] 1. Refers to soluble components with a retention factor of 2.0 or more when detected by high performance liquid chromatography using an ODS column. [Example]

[0087] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples in any way. [Quantitative determination of bromine content] Analysis method: Combustion-ion chromatography -Combustion conditions- Measurement equipment: Mitsubishi Chemical Analytech AQF-2100H Sample amount: 4 mg Combustion temperature: 900°C at the inlet, 1000°C at the outlet Absorption solution composition: 30 mg / L hydrogen peroxide solution Absorbed liquid volume: 30mL -IC conditions- Measuring device: Tosoh IC-2010 Analytical column: TSKgel SuperIC-Anion HS Guard column: TSKguardcolumn SuperIC-A HS Eluent: 7.5mmol / L sodium bicarbonate aqueous solution + 0.8mmol / L sodium carbonate aqueous solution Flow rate: 1.5mL / min Column temperature: 40℃ Injection volume: 30μL Suppressor gel: TSKgel suppress IC-A Detection: Electrical conductivity [Weight loss temperature measurement] Analytical equipment: Rigaku ThermoPlus TG8120 Measurement conditions: 10 mg of sample was heated in air at a rate of 10°C / min. [High-performance liquid chromatography analysis] Equipment used: Waters Acquity UPLC H-Class (Waters) Column: TSKgel ODS-100V (5 μm, 4.6 mm ID x 25 cm) Eluent: methanol / tetrahydrofuran = 99:1 Flow rate: 1.0mL / min Column temperature: 40℃ Injection volume: 10μL Detector: PDA (420 nm) [Chromaticity measurement] Analysis method: Colorimeter method Measuring device: Nippon Denshoku ZE-6000 Using 2.0 g of the brominated polyphenylene sulfide prepared in the examples, the color was measured using the color difference meter.

[0088] Whiteness W is calculated using the formula W=100-{(100-L) 2 +(a 2 +b 2 )} 1 / 2 It was calculated as follows.

[0089] The yellowness index YI was calculated according to ASTM E313. [Measurement of molecular weight (mass number)] Analysis method: MALDI-TOFMS Analyzer: JMS-S3000 manufactured by JEOL Ltd. Ionization method: LDI Measurement mode: Linear mode Ion polarity: Positive Laser Intensity: 60% Scan range: m / z 4~100000 Matrix: trans-2-[3-(4-tert-butylphenyl)-2-methyl-2-propenylidene]malononitrile Cationizing agent: sodium trifluoroacetate Comparative Example 1. Synthesis of conventionally known brominated polyphenylene sulfide The synthesis described below was carried out according to the method of EXAMPLE 6 described in Patent Document 6 (US4619961).

[0090] A 300 mL three-neck flask was charged with 113.2 g of bromine and cooled to 10°C. Then, 10.0 g of polyphenylene sulfide (Tosoh Corporation: Susteel #100, average molecular weight 20,000, repeat number = 185) was added in small increments over 30 minutes. The external temperature was then raised to 60°C, and the bromine was refluxed and stirred for 6 hours. During the 6-hour stirring period, 20 mL of bromine was added after 2 and 4 hours. After 6 hours, 1,2-dichloroethane was added to the reaction mixture, and unreacted bromine was distilled off. The reaction mixture was then cooled to room temperature and filtered to obtain the solid. The resulting solid was washed with 1,2-dichloroethane, air-dried, and then dried at 100°C for 3 hours, yielding 21.9 g of a brown solid. The bromine content of the resulting brown solid was measured to be 58.2%. The average values ​​of n and m calculated from the bromine content were n=m=1.94. The weight loss temperature was measured and found to be 311°C for 10% weight loss.

[0091] The chromaticity of the resulting brown solid (brominated polyphenylene sulfide) was measured, and the results are shown in Table 2.

[0092] The molecular weight (mass number) of the resulting white solid (brominated polyphenylene sulfide) was measured by MALDI-TOFMS, and the results are shown in Figure 1. A peak was observed in the mass number (m / z) range of 3,000 to 8,000. The average number of repeating units (p in the present invention) at the peak top (m / z = 4,718) was 17.3 (calculated assuming n = m = 1.94 (average value)).

[0093] 1 g of the brown solid (brominated polyphenylene sulfide) sample was placed in a cylindrical filter and placed in a Soxhlet extractor. An extract was obtained by heating 60 mL of acetone at 160°C under reflux for 140 minutes. The extract was dried by blowing nitrogen over it, then redissolved in 2 mL of a 1:1 methanol / tetrahydrofuran solution and further diluted 10-fold to obtain the test solution. The test solution was a brown, transparent solution. Since insoluble components precipitated during redissolution, the solution was filtered as needed. The results of high-performance liquid chromatography of the test solution are shown in Figure 2.

[0094] As shown in Figure 2, a peak of the colored component was confirmed at a retention factor of 2.0 or more (retention time of 7.4 minutes or later in Figure 2). The peak area ratio of the colored component was 28.4%.

[0095] Example 1. Synthesis of brominated polyphenylene sulfide A 300 mL three-neck flask was charged with 124.0 g of bromine and cooled to 10°C. Subsequently, 5.00 g of polyphenylene sulfide (Tosoh Corporation: Susteel #100, average molecular weight 20,000, repeat number = 185) was gradually added over 30 minutes. The external temperature was then raised to 60°C, and the bromine was refluxed and stirred for 5 hours. After 5 hours, 60 mL of 1,2-dichlorobenzene was added to the reaction solution, and the temperature was raised to 80°C to distill off unreacted bromine. The reaction solution was then cooled to 0°C, and aqueous sodium sulfite solution was added to reduce the traces of bromine remaining. Subsequently, aqueous sodium hydroxide solution was added to adjust the pH to 10. The resulting slurry was filtered, washed with water, and subsequently vacuum dried to yield 9.51 g of a white solid (brominated polyphenylene sulfide of the present invention). The bromine content of the resulting white solid was measured to be 58.6 wt%. The average values ​​of n and m calculated from the bromine content were n = m = 1.95. Measurement of the weight loss temperature revealed that the 10% weight loss temperature was 370°C. This demonstrates that the brominated polyphenylene sulfide of the present invention exhibits significantly higher heat resistance than conventional brominated polyphenylene sulfides.

[0096] The melting point was above 340°C, and decomposition began before the melting point was observed.

[0097] The chromaticity of the resulting white solid (brominated polyphenylene sulfide) was measured, and the results are shown in Table 1.

[0098] The molecular weight (mass number) of the obtained white solid (brominated polyphenylene sulfide) was measured by MALDI-TOFMS, and the results are shown in Figure 1. A peak was observed in the mass number (m / z) range of 12,000 to 24,000. The average number of repeating units (p in the present invention) at the peak top (m / z = 16,840) was 63.3 (calculated assuming n = m = 1.95 (average value)). Thus, it was found that the brominated polyphenylene sulfide synthesized in this example has a higher molecular weight than conventionally known brominated polyphenylene sulfides.

[0099] 1 g of the above white solid (brominated polyphenylene sulfide) sample was placed in a cylindrical filter and placed in a Soxhlet extractor. An extract was obtained by heating 60 mL of acetone at 160°C under reflux for 140 minutes. The extract was dried by blowing nitrogen over it, then redissolved in 2 mL of a 1:1 methanol / tetrahydrofuran solution and further diluted 10-fold to obtain the test solution. The test solution was a pale yellow, transparent solution. Insoluble components precipitated during redissolution, so the solution was filtered as needed. The results of high-performance liquid chromatography of the test solution are shown in Figure 3.

[0100] As shown in Figure 3, no peaks of colored components were observed at retention factors of 2.0 or higher (7.4 minutes or later in the retention time of Figure 1).

[0101] Example 2. Synthesis of brominated polyphenylene sulfide A 100 mL three-neck flask was charged with 5.00 g of polyphenylene sulfide (Tosoh Corporation: Susteel #100, average molecular weight 20,000, repeat number = 185) and 30 mL of 1,2-dichlorobenzene and stirred at 5°C. Then, 36.9 g of bromine was added dropwise over 30 minutes. The mixture was then heated to 60°C and stirred for 4 hours. After 4 hours, the mixture was heated to 90°C and nitrogen gas was blown in to distill off unreacted bromine. The reaction mixture was then added to acetone to reduce the traces of bromine remaining, followed by neutralization with aqueous sodium hydroxide. The resulting slurry was filtered, washed with water, and vacuum dried to yield 9.40 g of a white solid. The bromine content of the resulting white solid was measured to be 58.0%. The 10% weight loss temperature was measured to be 362°C. Therefore, it was found that the brominated polyphenylene sulfide of the present invention exhibits significantly higher heat resistance than conventional brominated polyphenylene sulfides.

[0102] The melting point was above 340°C, and decomposition began before the melting point was observed.

[0103] The chromaticity of the resulting white solid (brominated polyphenylene sulfide) was measured, and the results are shown in Table 1.

[0104] Example 3. Synthesis of brominated polyphenylene sulfide A 300 mL three-neck flask was charged with 124.0 g of bromine and cooled to 10°C. Subsequently, 5.00 g of polyphenylene sulfide (Tosoh Corporation: Susteel #100, average molecular weight 20,000, repeat number = 185) was gradually added over 30 minutes. The external temperature was then raised to 60°C, and the bromine was refluxed and stirred for 5 hours. After 5 hours, 60 mL of chlorobenzene was added to the reaction solution, and the temperature was raised to 80°C to distill off unreacted bromine. The reaction solution was then cooled to 0°C, and aqueous sodium sulfite solution was added to reduce the traces of bromine remaining. Subsequently, aqueous sodium hydroxide solution was added to adjust the pH to 10. The resulting slurry was filtered, washed with water, and subsequently vacuum dried to yield 9.51 g of a white solid (brominated polyphenylene sulfide of the present invention). The bromine content of the resulting white solid was measured to be 59.2 wt%. When the weight loss temperature was measured, the 10% weight loss temperature was 368° C. This indicates that the brominated polyphenylene sulfide of the present invention exhibits significantly higher heat resistance than conventional brominated polyphenylene sulfides.

[0105] The melting point was above 340°C, and decomposition began before the melting point was observed.

[0106] The chromaticity of the resulting white solid (brominated polyphenylene sulfide) was measured, and the results are shown in Table 1.

[0107] Example 4. Synthesis of brominated polyphenylene sulfide A 100 mL three-neck flask was charged with 5.00 g of polyphenylene sulfide (Tosoh Corporation: Susteel #100, average molecular weight 20,000, repeat number = 185) and 30 mL of chlorobenzene and stirred at 5°C. Then, 36.9 g of bromine was added dropwise over 30 minutes. The mixture was then heated to 60°C and stirred for 4 hours. After 4 hours, the mixture was heated to 90°C and nitrogen gas was blown in to distill off unreacted bromine. The reaction mixture was then added to acetone to reduce the traces of bromine remaining, followed by the addition of aqueous sodium hydroxide solution for neutralization. The resulting slurry was filtered, washed with water, and vacuum dried to yield 9.40 g of a white solid. The bromine content of the resulting white solid was measured to be 58.8%. The 10% weight loss temperature was measured to be 365°C. Therefore, it was found that the brominated polyphenylene sulfide of the present invention exhibits significantly higher heat resistance than conventional brominated polyphenylene sulfides.

[0108] The melting point was above 340°C, and decomposition began before the melting point was observed.

[0109] The chromaticity of the resulting white solid (brominated polyphenylene sulfide) was measured, and the results are shown in Table 1.

[0110] Example 5. Synthesis of brominated polyphenylene sulfide A 300 mL three-neck flask was charged with 124.0 g of bromine and cooled to 10°C. Subsequently, 5.00 g of polyphenylene sulfide (Tosoh Corporation: Susteel #100, average molecular weight 20,000, repeat number = 185) was gradually added over 30 minutes. The external temperature was then raised to 60°C, and the bromine was refluxed and stirred for 5 hours. After 5 hours, 60 mL of 1,2,4-trichlorobenzene was added to the reaction solution, and the temperature was raised to 80°C to distill off unreacted bromine. The reaction solution was then cooled to 0°C, and aqueous sodium sulfite solution was added to reduce the traces of bromine. Subsequently, aqueous sodium hydroxide solution was added to adjust the pH to 10. The resulting slurry was filtered, washed with water, and subsequently vacuum dried to yield 9.51 g of a white solid (brominated polyphenylene sulfide of the present invention). The bromine content of the obtained white solid was measured to be 58.4% by weight. The weight loss temperature was measured to be 366°C, indicating that the 10% weight loss temperature was 366°C. This demonstrates that the brominated polyphenylene sulfide of the present invention exhibits significantly higher heat resistance than conventional brominated polyphenylene sulfides.

[0111] The melting point was above 340°C, and decomposition began before the melting point was observed.

[0112] The chromaticity of the resulting white solid (brominated polyphenylene sulfide) was measured, and the results are shown in Table 2.

[0113] Example 6. Synthesis of brominated polyphenylene sulfide A 100 mL three-neck flask was charged with 5.00 g of polyphenylene sulfide (Tosoh Corporation: Susteel #100, average molecular weight 20,000, repeat number = 185) and 30 mL of 1,2,4-trichlorobenzene and stirred at 5°C. Then, 36.9 g of bromine was added dropwise over 30 minutes. The mixture was then heated to 60°C and stirred for 4 hours. After 4 hours, the mixture was heated to 90°C and nitrogen gas was blown in to distill off unreacted bromine. The reaction mixture was then added to acetone to reduce the traces of bromine remaining, followed by neutralization with aqueous sodium hydroxide. The resulting slurry was filtered, washed with water, and vacuum dried to yield 9.40 g of a white solid. The bromine content of the resulting white solid was measured to be 58.3%. The 10% weight loss temperature was measured to be 360°C. Therefore, it was found that the brominated polyphenylene sulfide of the present invention exhibits significantly higher heat resistance than conventional brominated polyphenylene sulfides.

[0114] The melting point was above 340°C, and decomposition began before the melting point was observed.

[0115] The chromaticity of the resulting white solid (brominated polyphenylene sulfide) was measured, and the results are shown in Table 2.

[0116] [Table 1]

[0117] [Table 2]

[0118] [Table 3]

[0119] As described above, the brominated polyphenylene sulfide of the present invention has a higher molecular weight, a higher whiteness, and a higher heat resistance than conventional products.

[0120] As described above, the brominated polyphenylene sulfide of the present invention is characterized by a higher degree of whiteness than conventional products, and when kneaded with a resin, it has the effect of suppressing changes in the original color tone of the resin.

Claims

1. The following general formula (1) 【Chemistry 1】 (wherein R represents a terminal group and represents a hydrogen atom or a bromine atom; n represents the number of bromine atoms bonded to the terminal benzene ring and represents a real number of 1 to 5; m represents the number of bromine atoms bonded to the benzene ring and represents a real number of 1 to 4; and p represents the number of repeating groups and represents a real number of 2 or more), and from the Lab values ​​of the brominated polyphenylene sulfide in a solid state at room temperature, the brominated polyphenylene sulfide is represented by the formula W=100−{(100−L) ２ + (a ２ +b ２ ) １／２ A brominated polyphenylene sulfide having a whiteness (W) of 70 or more as calculated by the above method.

2. The brominated polyphenylene sulfide represented by the general formula (1) is 【Chemistry 2】 2. The brominated polyphenylene sulfide according to claim 1, which is a brominated polyphenylene sulfide represented by the formula: (wherein R, n, m, and p are defined as in the general formula (1) above).

3. 3. The brominated polyphenylene sulfide according to claim 1, wherein the temperature at which 10% by weight of the brominated polyphenylene sulfide is reduced by 10% by weight on heating is 330°C or higher.

4. 4. The brominated polyphenylene sulfide according to claim 1, wherein the bromine content is 30 to 65% by weight.

5. 5. The brominated polyphenylene sulfide according to claim 1, which has a yellowness index (YI) calculated in accordance with ASTM E313 of 50 or less.

6. 6. The brominated polyphenylene sulfide according to claim 1, wherein p is a real number greater than 50 and equal to or less than 300.

7. A method for producing brominated polyphenylene sulfide according to any one of claims 1 to 6, comprising the following steps (1) to (4): Step (1): A step of mixing polyphenylene sulfide and bromine and heating the mixture to brominate the polyphenylene sulfide. Step (2): After the step (1), the unreacted bromine in the reaction solution obtained in the step (1) is removed by distillation in a state where the halogen-containing aromatic hydrocarbon solvent coexists in the reaction solution. Step (3): A step of adding a substance that reduces bromine or a substance that easily reacts with bromine to the reaction liquid remaining after the step (2) to obtain a slurry containing a solid of brominated polyphenylene sulfide. Step (4): A step of separating the solid (brominated polyphenylene sulfide) from the slurry obtained in the step (3) and washing the solid with a solvent.

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