Halogen-containing polymers and methods for their production

Abstract

To provide a flame retardant that has improved heat resistance and can give high flame retardance to a resin.SOLUTION: A halogen-containing polymer has at least one or more repeat units represented by the general formula (1 m) (where R is a C1-6 alkylene group, -S-, or -SO2-). In the halogen-containing polymer, the content of a polymer component with the number of the repeat units represented by the general formula (1 m) being 3 or more is at least 97% by area of the total in gel permeation chromatography measurement.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to halogen-containing polymers and methods for their preparation. [Background technology]

[0002] Flame retardants are widely known as additives that can impart flame-retardant properties to resins that are inherently flammable by being mixed into them. Among these, compounds containing large amounts of bromine, known as brominated flame retardants, have long been added to and used in many resins. For example, tetrabromobisphenol A, a typical brominated flame retardant, is known to be the most widely produced brominated flame retardant in the world, but in recent years, due to environmental considerations, there has been a strong trend toward converting it into a higher molecular weight compound for use. For example, Patent Document 1 reports a halogen-containing polymer (ethylene-crosslinked polymer of tetrabromobisphenol A). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 56-8809 Summary of the Invention [Problem to be solved by the invention]

[0004] The oligomer reported in Patent Document 1 does not have sufficiently high heat resistance, and the oligomer itself undergoes thermal decomposition in the high-temperature environment during resin kneading, making it impossible to impart sufficient flame retardancy to the resin. Therefore, there is a demand for flame-retardant materials with better heat resistance.

[0005] The present invention has been made in view of the above-mentioned background art, and an object of the present invention is to provide a halogen-containing polymer that is excellent in heat resistance and can be imparted with high flame retardancy. [Means for solving the problem]

[0006] As a result of extensive research into the above-mentioned problems, the inventors of the present application have found that low molecular weight components, such as monomers and dimers, contained in halogen-containing polymers affect the heat resistance of the halogen-containing polymers, and have also found that the heat resistance of the halogen-containing polymers can be improved by controlling the content of these low molecular weight components.

[0007] That is, the present invention relates to the following halogen-containing polymer and a method for producing the same. [1] The following general formula (1m)

[0008] [ka]

[0009] (In the formula, R represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-.) wherein the content of polymer components having 3 or more repeating units represented by general formula (1m) in the halogen-containing polymer is 97 area % or more of the total amount of the halogen-containing polymer, as measured by gel permeation chromatography. [2] The halogen-containing polymer according to [1], which has a weight-average molecular weight of 7,500 or more in terms of standard polystyrene as measured by gel permeation chromatography. [3] The halogen-containing polymer according to [1] or [2], wherein the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) in terms of standard polystyrene, as measured by gel permeation chromatography, is 1.0 to 4.0. [4] The halogen-containing polymer according to any one of [1] to [3], having a bromine content of 50 to 60% by weight. [5] At least the following general formula (1m)

[0010] [ka]

[0011] (In the formula, R represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-.) and a halogen-containing polymer composition in which the content of polymer components having 3 or more repeating units represented by general formula (1m) in the halogen-containing polymer is less than 97 area % of the total amount as measured by gel permeation chromatography is immersed in an organic solvent selected from the group consisting of halogen-containing organic solvents, nitrogen-containing solvents, and ether-based organic solvents, or a mixture of two or more organic solvents, and the component having less than 3 repeating units is extracted from the halogen-containing polymer composition. [6] The following general formula (3)

[0012] [ka]

[0013] (In the formula, R represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-. X represents a halogen atom.) and a compound represented by the following general formula (4):

[0014] [ka]

[0015] (In the formula, R represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-. M + represents an alkali metal ion or a substituted or unsubstituted ammonium ion. to react a compound represented by general formula (1m)

[0016] [ka]

[0017] (In the formula, R represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-.) and a halogen-containing polymer composition containing a halogen-containing polymer having at least one repeating unit represented by general formula (1m) having 3 or more repeating units, the halogen-containing polymer comprising a polymer component having 3 or more repeating units, and the halogen-containing polymer composition ... [Effects of the Invention]

[0018] The halogen-containing polymer of the present invention has superior heat resistance compared to conventionally known halogen-containing polymers, and therefore has excellent stability in high-temperature environments during resin kneading, thereby providing the effect of imparting excellent flame retardancy to the resin. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be described in detail below.

[0020] The present invention is a halogen-containing polymer having at least one repeating unit represented by the above general formula (1m), characterized in that the content of polymer components having three or more repeating units represented by the above general formula (1m) in the halogen-containing polymer is 97 area % or more of the total, as measured by gel permeation chromatography.

[0021] In terms of the production method, the halogen-containing polymer of the present invention preferably has a terminal group that is a 2-haloethyl group, a vinyl group (produced by dehydrohalogenation of the 2-haloethyl group), or a phenolic hydroxyl group (or its alkali metal (e.g., Li, Na, or K) salt). However, any of these may be used, or the terminal can be controlled to any desired terminal by separate terminal modification. Since both of these terminal groups are reactive functional groups, the terminals can also be capped with a non-reactive or low-reactive functional group. The capping method is not particularly limited, and examples include a method of reacting with a compound having only one substituent that can react with the reactive functional group, such as 4-bromophenol, 1,3,5-tribromophenol, pentabromophenol, benzyl chloride, or a benzyl halide in which the aromatic nucleus is substituted with a halogen. Polymers with capped terminal groups are also included in the polymer of the present invention.

[0022] In the above general formula (1m), R represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-.

[0023] The alkylene group having 1 to 6 carbon atoms represented by R is not particularly limited, but examples thereof include a methylene group, an ethylene group, a 2,2-propylene group, a 2,2-butylene group, a hexadiene group, and a 1,1-cyclohexylene group.

[0024] The above R is preferably a methylene group or a 2,2-propylene group, more preferably a 2,2-propylene group, in view of excellent heat resistance.

[0025] The halogen-containing polymer having at least one repeating unit represented by the general formula (1m) is not particularly limited, and examples thereof include a condensation polymer obtained from tetrabromobisphenol F and dichloroethane, a condensation polymer obtained from tetrabromobisphenol A and dichloroethane, a condensation polymer obtained from bisphenol F, tetrabromobisphenol F and dichloroethane, and a condensation polymer obtained from bisphenol A, tetrabromobisphenol A and dichloroethane. Of these, a condensation polymer obtained from tetrabromobisphenol A and dichloroethane, i.e., a condensation polymer in which R is a 2,2-propylene group, is preferred.

[0026] The halogen-containing polymer of the present invention is characterized in that the content of polymer components having 3 or more repeating units represented by the general formula (1m) is 97% or more by area based on the total polymer, as measured by gel permeation chromatography. That is, the halogen-containing polymer of the present invention is characterized in that the content of components having less than 3 repeating units represented by the general formula (1m) (hereinafter also referred to as "low molecular weight components") is less than 3% by area based on gel permeation chromatography.

[0027] The low molecular weight component is not particularly limited, but examples thereof include compounds represented by the above general formula.

[0028] [ka]

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

[0030] [ka]

[0031] (In the above formula, R represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-. X represents a halogen atom or a hydroxyl group.) The halogen-containing polymer of the present invention is characterized in that the content of the polymer component having 3 or more repeating units represented by the general formula (1m) is 97 area % or more of the total, as measured by gel permeation chromatography. In order to obtain higher heat resistance, the content is more preferably 98 area % or less of the total, and even more preferably 99 area % or less.

[0032] That is, the halogen-containing polymer of the present invention is characterized in that the low molecular weight component accounts for less than 3 area % of the total when measured by gel permeation chromatography. However, in order to obtain higher heat resistance, it is preferable that the content of the low molecular weight component is low, more preferably less than 2 area % of the total, and more preferably less than 1 area %. Note that the retention time of the gel permeation chromatography peak derived from the low molecular weight component varies depending on the gel permeation chromatography analysis conditions, but it can be identified using a standard sample or the molecular weight converted into standard polystyrene. Furthermore, it is preferable that the halogen-containing polymer of the present invention has a low content of the low molecular weight component, from the viewpoint of suppressing odor generated during dimer decomposition.

[0033] The halogen-containing polymer of the present invention preferably has a weight average molecular weight, calculated as standard polystyrene by gel permeation chromatography, of 2,000 or more, more preferably 4,000 or more, even more preferably 6,000 or more, and still more preferably 7,500 or more, in terms of achieving higher heat resistance.

[0034] The halogen-containing polymer of the present invention preferably has a ratio (Mw / Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) in terms of standard polystyrene, measured by gel permeation chromatography, of 1.0 to 4.0. However, the smaller the Mw / Mn, the narrower the molecular weight distribution of the polymer, and the higher the flame retardancy and heat resistance of the polymer itself. Therefore, Mw / Mn is more preferably 1.0 to 3.0, and more preferably 1.0 to 2.0.

[0035] The method and conditions for measuring the molecular weight of the halogen-containing polymer of the present invention by gel permeation chromatography were in accordance with ISO 16014-3:2012 (JIS K 7252-3:2016). The low molecular weight components can also be analyzed using the above-mentioned gel permeation chromatography.

[0036] The halogen-containing polymer of the present invention preferably has a bromine content of 50 to 60% by weight. However, from the viewpoint that the higher the bromine content, the more improved the flame retardancy of the flame retardant itself, the more preferable the bromine content is 53 to 60% by weight.

[0037] The bromine content (wt%) of the halogen-containing polymer 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.

[0038] The halogen-containing polymer of the present invention is characterized by a high weight loss temperature. Specifically, the polymer of the present invention has excellent heat resistance (low thermal decomposition), and the temperature at which a 20% weight loss occurs at a temperature increase rate of, for example, 10°C / min is preferably 370°C or higher, and more preferably 380°C or higher.

[0039] The 10% thermal weight loss temperature was measured using a differential heating / thermogravimetric simultaneous analyzer (TG-DTA2020SA, manufactured by Bruker AXS) in an aluminum container with a sample of approximately 10 mg, 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.

[0040] The halogen-containing polymer having at least one repeating unit represented by the above general formula (1m) is not particularly limited, but examples thereof include those represented by the following general formula (1):

[0041] [ka]

[0042] (In the formula, R represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-. n represents a real number having an average value of 1 or more. Note that R has the same definition as R in general formula (1m), and the preferred range is also the same.) A preferred example is a halogen-containing polymer represented by the following formula:

[0043] The real number n as the average value is determined by gel permeation chromatography measurement, and from the viewpoint of excellent heat resistance, it is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more. Furthermore, from the viewpoint of excellent handling as a flame retardant, the real number n is preferably 50 or less, more preferably 30 or less, and even more preferably 20 or less.

[0044] In the halogen-containing polymer represented by the general formula (1), the content of polymer components where n is 3 or more is preferably 97 area % or more of the total, preferably 98 area % or more of the total, and preferably 99 area % or more of the total, as measured by gel permeation chromatography. That is, in the halogen-containing polymer represented by the general formula (1), the content of components where n is less than 3 (the same as the "low molecular weight components" in the general formula (1m)) is preferably less than 3 area %, preferably less than 2 area %, and preferably less than 1 area % of the total, as measured by gel permeation chromatography.

[0045] Based on these physical properties of the halogen-containing polymer of the present invention, the halogen-containing polymer of the present invention is effective in imparting flame retardancy not only to general-purpose resins but also to highly heat-resistant resins such as engineering plastics.

[0046] Resins that can be imparted with flame retardancy are not particularly limited, but examples include 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, polyimide imide, and the like.

[0047] The halogen-containing polymer of the present invention has at least the following general formula (1m):

[0048] [ka]

[0049] (In the formula, R represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-.) The halogen-containing polymer composition contains a halogen-containing polymer having at least one repeating unit represented by the general formula (1m), and the content of the halogen-containing polymer component having three or more repeating units represented by the general formula (1m) in the halogen-containing polymer accounts for less than 97 area % of the total amount as measured by gel permeation chromatography. The halogen-containing polymer composition can be produced by immersing the composition in an organic solvent selected from the group consisting of halogen-containing organic solvents, nitrogen-containing solvents, and ether-based organic solvents, or an organic solvent consisting of a mixture of two or more organic solvents, and extracting the component having less than three repeating units from the composition.

[0050] In addition, in the case of a halogen-containing polymer composition in which the content of the halogen-containing polymer component having 3 or more repeating units represented by the general formula (1m) is less than 97 area % of the whole as measured by gel permeation chromatography,

[0051] [ka]

[0052] (In the formula, R represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-. X represents a halogen atom.) and a compound represented by the following general formula (4):

[0053] [ka]

[0054] (In the formula, R represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-. M + represents an alkali metal ion or a substituted or unsubstituted ammonium ion. The compound can be produced by reacting a compound represented by the formula:

[0055] The definition and preferred range of R in the above general formulas (3) and (4) are the same as the definition and preferred range of R shown in general formula (1m).

[0056] In the general formula (3), each X independently represents a halogen atom, and the halogen atom is not particularly limited, but examples thereof include a chlorine atom, a bromine atom, an iodine atom, etc. Among these, X is preferably a chlorine atom in view of excellent production efficiency of the halogen-containing polymer of the present invention.

[0057] In the above general formula (4), M + each independently represents an alkali metal ion or a substituted or unsubstituted ammonium ion.

[0058] The alkali metal ions are not particularly limited, but may be, for example, Li ions, Na ions, or K ions.

[0059] The substituted or unsubstituted ammonium ion is not particularly limited, but examples thereof include ammonium ion, monomethylammonium ion, dimethylammonium ion, trimethylammonium ion, tetramethylammonium ion, monoethanolammonium ion, diethanolammonium ion, and triethanolammonium ion.

[0060] The compound represented by the general formula (4) preferably contains at least a Na ion. + A compound in which at least a part of the ions are Na ions is preferred, and M + is more preferably a Na ion.

[0061] In the production method of the present invention, the halogen-containing polymer having one or more repeating units represented by general formula (1m) is preferably a halogen-containing polymer represented by general formula (1), as described above.

[0062] The low molecular weight components can be removed from the halogen-containing polymer composition by extraction using an organic solvent consisting of one organic solvent selected from the group consisting of halogen-containing organic solvents, nitrogen-containing solvents, and ether-based organic solvents, or a mixture of two or more organic solvents.

[0063] The method of extraction using an organic solvent is not particularly limited, but examples include a method in which the halogen-containing polymer is placed in a container, the organic solvent is added thereto, and the mixture in the container is stirred.

[0064] The halogen-containing organic solvent is not particularly limited, but examples thereof include dichloromethane, 1,2-dichloroethane, 1,2-dibromoethane, 1,1,2-trichloroethane, chloroform, tetrachloroethane, chlorobenzene, and 1,2-dichlorobenzene. Dichloromethane, 1,2-dichloroethane, 1,1,2-trichloroethane, and chloroform are preferred, and 1,2-dichloroethane is more preferred.

[0065] The nitrogen-containing organic solvent is not particularly limited, but examples thereof include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, pyridine, pyrrole, acetonitrile, and nitrobenzene. N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone are preferred, and N-methyl-2-pyrrolidone is more preferred.

[0066] The ether-based organic solvent is not particularly limited, but examples thereof include tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, cyclopentyl methyl ether, diethyl ether, polyethylene glycol, and methyl cellosolve, with tetrahydrofuran, 2-methyltetrahydrofuran, and 1,4-dioxane being preferred, and tetrahydrofuran being more preferred.

[0067] The amount of organic solvent added in the extraction using an organic solvent is not particularly limited, but can be, for example, 0.1 to 1000 parts by weight per 1 part by weight of the halogen-containing polymer. In order to improve the efficiency of organic solvent washing, the amount of organic solvent washing solution added is preferably an amount sufficient to allow the halogen-containing polymer to be easily stirred and mixed, and specifically, for example, 5 to 100 parts by weight per 1 part by weight of the halogen-containing polymer is preferably 5 to 100 parts by weight, more preferably 5 to 10 parts by weight.

[0068] The temperature for extraction using an organic solvent is not particularly limited, but can be, for example, in the range of 4 to 80°C, and is preferably from room temperature (15 to 25°C) to about 40°C.

[0069] The processing time for extraction using an organic solvent is not particularly limited, but can be, for example, in the range of 1 minute to 48 hours. However, in terms of being able to remove the low molecular weight components, it is preferable to set it in the range of 1 to 24 hours.

[0070] For the halogen-containing polymer that has been subjected to extraction treatment using an organic solvent, it is preferable to perform an additional drying treatment to remove the adhering solvent. Examples of the drying treatment include vacuum drying and hot air drying, and the purpose is to remove the adhering solvent.

[0071] By carrying out extraction using the organic solvent, it is possible to reduce or remove the low molecular weight components by-produced in the polymerization process for producing the halogen-containing polymer, and as a result, it is possible to adjust the low molecular weight components in the halogen-containing polymer.The low molecular weight components contained in the halogen-containing polymer have low heat resistance, and are presumed to undergo decomposition under high temperature conditions during resin kneading, causing a decrease in the flame retardancy of the resin, and it is presumed that the flame retardancy of the resin can be improved by reducing such low molecular weight components. [Brief explanation of the drawings]

[0072] [Figure 1] 1 shows a gel permeation chromatography chart of the halogen-containing polymer (B-1) synthesized in Example 1. [Figure 2] 1 shows a gel permeation chromatography chart of the halogenated polymer (B-2) synthesized in Comparative Example 1. [Explanation of symbols]

[0073] 1. Dimer-derived peak 2. Peak derived from monomer (compound corresponding to general formula (3)) 3. Peaks derived from unreacted tetrabromobisphenol A [Example]

[0074] <Molecular weight analysis method, low molecular weight component analysis method> The polymer samples synthesized in the examples were measured using a gel permeation chromatography system (Tosoh Corporation, HLC-8320GPC) connected to a molecular weight measurement column (Tosoh Corporation, TSKgel® SuperAW2500+3000+5000) at a flow rate of 0.6 mL / min with chloroform eluent at 40°C and UV (254 nm) detection. Furthermore, the weight average molecular weight of the sample was measured using standard polystyrene. Other measurements were performed in accordance with JIS-K-7252. <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> TG analysis was performed on each sample (polymer or oligomer) obtained in Example 1 and Comparative Example 1 using a TG-DTA measuring instrument (TG-DTA2020SA, manufactured by Bruker AXS). Measurements were performed on 10 mg of sample in air, with the temperature increased at a rate of 10°C / min. The results are shown in Table 1. <Melt point, color onset temperature, and odor / fume measurement> The melting points of each sample of the polymer of Example 1 and the oligomer of Comparative Example 1 were measured using a melting point measuring device (ATM-01, manufactured by AS ONE Corporation). In addition, the coloration onset temperature was measured as the temperature continued to rise. Furthermore, when the temperature reached 300°C, the presence or absence of odor and smoke was confirmed for each sample. The presence or absence of odor was confirmed by the nose of the person conducting the measurement, and the presence or absence of smoke was confirmed visually. The results are shown in Table 2.

[0075] 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.

[0076] Example 1 <Synthesis of halogen-containing polymer (B-1)> 550 g (1.01 mol) of tetrabromobisphenol A, 200 g (2.38 mol) of sodium bicarbonate, 800 g (8.08 mol) of 1,2-dichloroethane, and 3.1 L of dimethylformamide were added to an 8 L glass eggplant-shaped flask in this order at room temperature, and the mixture was then heated to 90 °C with mixing. After stirring at the same temperature for 3 hours, unreacted 1,2-dichloroethane was distilled off under reduced pressure at 80 °C. After cooling to room temperature, 550 g (1.01 mol) of tetrabromobisphenol A, 170 g (2.02 mol) of sodium bicarbonate, and 3.1 L of dimethylformamide were added. The mixture was stirred at 135 °C for 9 hours and then allowed to cool to room temperature. Water was added, and the precipitated solid was filtered and washed with water. The mixture was then dried with hot air at 80 °C, yielding 1.15 kg of a white solid. The dimer content and monomer content in the white solid were 2 area % and 2 area %, respectively. The content of the polymer component having three or more repeating units represented by the general formula (1m) was 95 area % of the total. 1.15 kg of the resulting white solid was added to 10 L of 1,2-dichloroethane and stirred at 40°C for 1 hour. The solid was then filtered and dried to obtain a white solid (polymer) in an 80% yield (corresponding to the "halogen-containing polymer" of the present invention). This polymer is hereinafter referred to as halogen-containing polymer (B-1). The resulting halogen-containing polymer (B-1) had a weight-average molecular weight of 12,000 in terms of standard polystyrene as determined by gel permeation chromatography. A gel permeation chromatogram of the resulting halogen-containing polymer (B-1) is shown in Figure 1. The content of the polymer component having three or more repeating units represented by the general formula (1m) in the resulting halogen-containing polymer (B-1) was 98 area % of the total. The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the obtained halogen-containing polymer (B-1) calculated in terms of standard polystyrene was calculated to be 1.6. The bromine content of the obtained halogen-containing polymer (B-1) was measured to be 54.9 wt%.

[0077] Comparative Example 1 <Synthesis of halogenated polymer (B-2)> A polymer was synthesized in 78% yield according to the method of Example 14 described in Patent Document 1 (JP-B-56-8809). This polymer is hereinafter referred to as halogenated polymer (B-2). The resulting halogenated polymer (B-2) had a weight-average molecular weight of 3,500 in terms of standard polystyrene. A gel permeation chromatogram of the resulting halogenated polymer (B-2) is shown in Figure 2. The resulting halogenated polymer (B-2) contained 12 area % of dimer, 11 area % of monomer, and 6 area % of unreacted tetrabromobisphenol A. The content of polymer components having three or more repeating units represented by the general formula (1m) was 70 area %. The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the obtained halogenated polymer (B-2) in terms of standard polystyrene was calculated to be 11. The bromine content of the obtained halogenated polymer (B-2) was measured to be 53.2% by weight.

[0078] Using a TG-DTA measuring instrument (TG-DTA2020SA manufactured by Bruker AXS), TG analysis was performed on the halogen-containing polymer (B-1) and the halogenated polymer (B-2) obtained in Example 1 and Comparative Example 1. The results are shown in Table 1.

[0079] [Table 1]

[0080] [Table 2]

[0081] <Flame retardancy measurement> The materials used in the flame retardancy measurements are listed below. <Polypropylene resin (A)> Polypropylene: MA3 (trade name), manufactured by Japan Polypropylene Co., Ltd. <Flame retardant (B)> Flame retardant B-1: The halogen-containing polymer (B-1) described above.

[0082] Flame retardant B-2: Halogenated polymer (B-2) described above. <Antimony-based flame retardant synergist (C)> Antimony trioxide: manufactured by Suzuhiro Chemical Co., Ltd., (trade name) AT3CN.

[0083] First, a polyamide resin composition was prepared by compounding. For this purpose, the individual components (flame retardant (B-1), polypropylene, and antimony trioxide) listed in Table 1 were mixed in a twin-screw extruder (KTX-30, manufactured by Kobe Steel, Ltd.) at a temperature of 190 to 220°C. The polypropylene resin composition was extruded as a strand and then pelletized. The resulting pellets of the polypropylene resin composition were molded at a temperature of 220°C to prepare standard test pieces for the flame retardancy test (oxygen index measurement). The oxygen index measurement was performed in accordance with JIS-K-7201 using an oxygen index value-based flammability tester (ON-2M, manufactured by Suga Test Instruments). The results are shown in Table 2. The higher the oxygen index value in Table 2, the higher the flame retardancy.

[0084] [Table 3]

[0085] Tables 1 and 2 show that the halogen-containing polymers of the present invention exhibit higher heat resistance than halogenated polymers obtained by known production methods. Furthermore, Table 3 shows that the halogen-containing polymers of the present invention exhibit excellent flame retardant properties. This is thought to be because adjusting the amount of low-molecular-weight components in the halogen-containing polymer improves the heat resistance of the halogen-containing polymer itself, thereby suppressing decomposition under high-temperature conditions during resin kneading.

Claims

1. The following general formula (1m) 【Chemical 1】 (wherein R represents an alkylene group having 1 to 6 carbon atoms, —S—, or —SO ２ - indicates.) wherein the content of polymer components having 3 or more repeating units represented by general formula (1m) in the halogen-containing polymer is 97 area % or more of the total amount of the polymer, as measured by gel permeation chromatography.

2. 2. The halogen-containing polymer according to claim 1, which has a weight average molecular weight of 7,500 or more in terms of standard polystyrene as measured by gel permeation chromatography.

3. 3. The halogen-containing polymer according to claim 1, wherein 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 1.0 to 4.

0.

4. 4. The halogen-containing polymer according to claim 1, wherein the bromine content is 50 to 60% by weight.

5. At least the following general formula (1m) 【Chemistry 2】 (wherein R represents an alkylene group having 1 to 6 carbon atoms, —S—, or —SO ２ - indicates.) and a content of polymer components having 3 or more repeating units represented by general formula (1m) in the halogen-containing polymer is less than 97 area % of the total halogen-containing polymer as measured by gel permeation chromatography, the content being determined by gel permeation chromatography. The method for producing a halogen-containing polymer according to any one of claims 1 to 4, characterized by immersing the halogen-containing polymer composition in an organic solvent selected from the group consisting of halogen-containing organic solvents, nitrogen-containing solvents, and ether-based organic solvents, or a mixture of two or more organic solvents, and extracting the component having less than 3 repeating units from the halogen-containing polymer composition.

6. The following general formula (3) 【Chemistry 3】 (wherein R represents an alkylene group having 1 to 6 carbon atoms, —S—, or —SO ２ - represents a halogen atom. and a compound represented by the following general formula (4): 【Chemistry 4】 (wherein R represents an alkylene group having 1 to 6 carbon atoms, —S—, or —SO ２ - indicates. ＋ represents an alkali metal ion or a substituted or unsubstituted ammonium ion. to react a compound represented by the general formula (1m) 【Chemistry 5】 (wherein R represents an alkylene group having 1 to 6 carbon atoms, —S—, or —SO ２ - indicates.) and a halogen-containing polymer composition containing a halogen-containing polymer having at least one repeating unit represented by general formula (1m) and a polymer component having three or more repeating units, the polymer component accounting for less than 97 area % of the halogen-containing polymer as measured by gel permeation chromatography; and then immersing the halogen-containing polymer composition in an organic solvent selected from the group consisting of halogen-containing organic solvents, nitrogen-containing organic solvents, and ether-based organic solvents, or in an organic solvent consisting of a mixture of two or more organic solvents, to extract the component having less than three repeating units from the halogen-containing polymer composition.

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