Flame retardant auxiliary granules, method for producing the granules, and flame retardant-blended resin composition containing the granules

Abstract

To provide flame-retardant air granules which prevent scattering of an inorganic flame-retardant aid such as diantimony trioxide, have versatility, and do not reduce flame retardancy, more preferably, flame-retardant air granules which are excellent in one or more of adhesion of a resin film, mechanical strength and dispersibility.SOLUTION: Flame-retardant air granules contain (A) one or more flame-retardant air inorganic particles selected from a group consisting of a flame-retardant inorganic oxide, a flame-retardant inorganic acid salt and a flame-retardant inorganic sulfide, and (B) one or more halogen-based flame retardants containing a halogenated epoxy resin, wherein a weight ratio of (B) / (A) is 1 / 99 to 50 / 50, and at least a part of the surface of (A) the flame-retardant air inorganic particles is coated with (B) the one or more halogen-based flame retardants containing the halogenated epoxy resin.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a flame retardant auxiliary which has almost no flame retardant effect when used alone, but which exhibits a synergistic flame retardant effect when combined with other flame retardants. [Background technology]

[0002] Flame retardant synergists such as diantimony trioxide are inorganic powders that can scatter during the production of flame retardant compositions, potentially worsening the working environment and adversely affecting the health of workers. In particular, diantimony trioxide has been newly added to the list of specified chemical substances (controlled category 2 substances) under the Ordinance on Prevention of Harm from Specified Chemical Substances. Therefore, there is an urgent need to improve the anti-scattering properties of antimony trioxide to comply with the regulations. As a technique for improving such shatter prevention, a masterbatch composition (Patent Documents 1 to 3) is known in which a specific flame retardant and a flame retardant aid are blended at high concentrations in a specific resin. In addition, flame retardant compositions coated with curable resins such as thermosetting acrylic melamine resins, thermosetting water-soluble methylol polyvinyl urethane resins, thermosetting water-soluble melamine resins, and thermosetting water-soluble phenolic resins have been proposed (Patent Document 4). In addition, a flame retardant composition has been proposed that consists of granular material containing an inorganic flame retardant containing antimony oxide as an essential component, a fatty acid amide (hard binder), and a lubricant (having a lower melting point than the fatty acid amide; for example, a fatty acid, a metal soap, or its ester) (Patent Document 5). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-105432 [Patent Document 2] Japanese Patent Publication No. 2020-105433 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-218204 [Patent Document 4] Japanese Patent Publication No. 60-8338 [Patent Document 5] Japanese Patent Application Publication No. 6-256763 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the case of a high-concentration masterbatch composition encapsulated in a specific resin, the dispersibility is governed by the dispersibility of the specific resin, and therefore it lacks versatility. For example, since polyethylene resin or polypropylene resin is incompatible with polyethylene terephthalate resin, when a high-concentration masterbatch composition is used with a polypropylene resin as the specific resin, aggregation occurs, and the flame retardancy and mechanical strength are lower than when the masterbatch composition is not used. Furthermore, even when diantimony trioxide is coated with a curable resin such as melamine resin, there is still room for improvement in the adhesion between the resin film and diantimony trioxide, mechanical strength, etc. Furthermore, although melamine resins are generally considered to be flame-retardant, this is not necessarily sufficient. Furthermore, granulating antimony oxide with a fatty acid amide / lubricant means using a combustible substance to form the granules, which reduces the flame retardancy of the flame retardant auxiliary granules. Therefore, an object of the present invention is to provide flame-retardant auxiliary granules that prevent scattering of inorganic flame-retardant auxiliary agents such as diantimony trioxide, are versatile, and do not reduce flame retardancy, and more preferably, are excellent in one or more of the adhesion of the coating film, mechanical strength, and dispersibility. [Means for solving the problem]

[0005] The first aspect of the present invention is (A) one or more flame retardant auxiliary inorganic particles selected from the group consisting of flame retardant auxiliary inorganic oxides, flame retardant auxiliary inorganic acid salts, and flame retardant auxiliary inorganic sulfides; and (B) one or more halogen-based flame retardants including a halogenated epoxy resin, The weight ratio of (B) / (A) is 1 / 99 to 50 / 50, The flame-retardant synergist granules comprise (A) inorganic particles of a flame-retardant synergist, at least a portion of the surface of which is coated with (B) one or more halogen-based flame retardants including a halogenated epoxy resin.

[0006] A second aspect of the present invention is (I) (A) a step of adding and mixing one or more flame-retardant auxiliary inorganic particles selected from the group consisting of flame-retardant auxiliary inorganic oxides, flame-retardant auxiliary inorganic acid salts, and flame-retardant auxiliary inorganic sulfides with (B) one or more halogen-based flame retardants including a halogenated epoxy resin, wherein the weight ratio of (B) / (A) is 1 / 99 to 50 / 50; and (II) The method for producing flame-retardant auxiliary granules includes a step of drying the granules obtained in step (I).

[0007] A third aspect of the present invention is The flame-retardant-blended resin composition comprises the flame-retardant auxiliary granules of the first aspect of the present invention, a flame retardant, and a resin, and is characterized in that the flame-retardant auxiliary granules are present in an amount of 0.1 to 50 parts by weight per 100 parts by weight of the total amount of the resin and the flame retardant. [Effects of the Invention]

[0008] The flame-retardant auxiliary granules of the present invention can prevent scattering of the inorganic flame-retardant auxiliary, are versatile, do not reduce flame retardancy, and more preferably are excellent in one or more of the adhesion, mechanical strength, and dispersibility of the coating film. [Brief explanation of the drawings]

[0009] [Figure 1] This is a scanning electron microscope photograph (magnification: 10,000 times) of the raw material, untreated diantimony trioxide. [Figure 2] This is a scanning electron microscope photograph (magnification: 10,000 times) of the surface of flame retardant auxiliary granules obtained by mixing and grinding halogenated epoxy resin (NF-300VLG) and diantimony trioxide in a weight ratio (50 / 50) at 200°C for 1 hour. DETAILED DESCRIPTION OF THE INVENTION

[0010] (1) First Aspect of the Present Invention (A) one or more flame retardant auxiliary inorganic particles selected from the group consisting of flame retardant auxiliary inorganic oxides, flame retardant auxiliary inorganic acid salts, and flame retardant auxiliary inorganic sulfides; and (B) one or more halogen-based flame retardants including a halogenated epoxy resin, The weight ratio of (B) / (A) is 1 / 99 to 50 / 50, The flame-retardant synergist granules comprise (A) inorganic particles of a flame-retardant synergist, at least a portion of the surface of which is coated with (B) one or more halogen-based flame retardants including a halogenated epoxy resin.

[0011] (1-1) The flame retardant auxiliary granules of this embodiment are coated with one or more halogen-based flame retardants including halogenated epoxy resins, and therefore can prevent scattering of the flame retardant auxiliary. Furthermore, halogenated epoxy resins have good compatibility with many resins, and can therefore be used with good versatility in producing flame retardant-containing resin compositions. Furthermore, since the coating material is a halogen-based flame retardant, the coating does not adversely affect flame retardancy. More preferably, the coating film is excellent in one or more of adhesion, mechanical strength, and dispersibility. (i) The airborne concentration of the flame retardant auxiliary granules of this embodiment is preferably 0.1 mg / m in terms of metal atoms in the inorganic particles of the flame retardant auxiliary. 3 More preferably, 0.1 mg / m or less in terms of inorganic particles of flame retardant auxiliary agent 3 The following is the result. The concentration of airborne particles when the container is opened or inserted is measured by atomic absorption spectrometry. (ii) The adhesion of the coating film can be evaluated by the solid content retention rate after hot toluene extraction or the solid content retention rate after hot water extraction. That is, extraction is performed using a Soxhlet extractor in accordance with JIS K6229:2015, Method C. In the flame retardant auxiliary granules of this embodiment, the solid content after hot toluene extraction is preferably maintained at 60% or more, more preferably 80% or more. Furthermore, in accordance with JIS K6229:2015, Method C, in the flame retardant auxiliary inorganic granules of this embodiment, the solid content after hot water extraction is preferably maintained at 70% or more, more preferably 90% or more. The solid content remaining rate can also be converted into a coating maintenance rate. Here, the coating retention rate refers to the post-extraction coating equivalent weight, expressed in weight %, obtained by subtracting the weight of the inorganic flame retardant auxiliary particles contained in the flame retardant auxiliary granules from the weight of the flame retardant auxiliary granules after hot toluene extraction, where the pre-extraction coating equivalent weight, obtained by subtracting the weight of the inorganic flame retardant auxiliary particles contained in the flame retardant auxiliary granules from the weight of the flame retardant auxiliary granules before hot water extraction, is taken as 100. Such a coating retention rate is preferably 0.1% or more, more preferably 1% or more, even more preferably 3% or more, and particularly preferably 4% or more. Alternatively, the coating retention rate refers to the post-extraction coating equivalent weight, obtained by subtracting the weight of the inorganic flame retardant auxiliary particles contained in the flame retardant auxiliary granules from the weight of the flame retardant auxiliary granules after hot water extraction, where the pre-extraction coating equivalent weight, obtained by subtracting the weight of the inorganic flame retardant auxiliary particles contained in the flame retardant auxiliary granules from the weight of the flame retardant auxiliary granules before hot water extraction, is taken as 100. The coverage retention rate is preferably 80% or more, and more preferably 90% or more. The adhesion between the coating, which is composed of one or more halogen-based flame retardants including halogenated epoxy resins, and the inorganic particles of the flame retardant synergist is good. Without being bound by theory, it is believed that the improved adhesion is due to the interaction between the oxygen or sulfur atoms in the inorganic oxides, acid salts, and sulfides of the flame retardant synergist and the epoxy groups of the halogenated epoxy resins in the coating. The adhesion of the coating film can also be inferred from the data on the good coverage rate and contact angle. (iii) Furthermore, the granule strength of the flame retardant auxiliary granules of this embodiment can be evaluated by conducting a compression test (tablet hardness test using a texture analyzer) and measuring the pressure required to cause breakage in the cross section of the granule (breaking strength). From the viewpoint that granules that are easy to break but do not break during handling are preferred, granules are first passed through a plain weave wire mesh of mesh 2 (wire diameter 2.0), and then the remaining granules are sorted through a plain weave wire mesh of mesh 4 (wire diameter 2.0). Of the granules obtained, granules that are as flat or columnar as possible and suitable for a compression test are selected, and the pressure at the time of breakage is preferably 1 to 300 N, more preferably 10 to 200 N. Breakage begins at the interface between the flame retardant synergist and the resin.

[0012] (1-2) The inorganic particles of the flame retardant assistant used in the present invention are at least one type of inorganic particles of the flame retardant assistant selected from the group consisting of inorganic oxides, inorganic acid salts, and inorganic sulfides. Here, the flame retardant synergist refers to an agent that has almost no flame retardant effect when used alone, but when combined with other flame retardants, it exerts a synergistic flame retardant effect. Specific examples of the inorganic particles of the flame retardant aid used in the present invention include one or more selected from the group consisting of antimony oxide, antimonate, zinc sulfide, zinc borate, zinc stannate, and activated alumina. Among these, diantimony oxides include diantimony trioxide (III) Sb2O3, diantimony pentoxide (V) Sb2O5, and diantimony tetroxide Sb2O4. III and Sn V It is believed to be a mixed oxide of In particular, it is convenient to use flame retardant auxiliary inorganic particles containing diantimony trioxide, which has been newly added to the list of specific chemical substances (controlled Class 2 substances) under the Ordinance on Prevention of Hazards Caused by Specified Chemical Substances and is required to comply with regulations to prevent scattering, as the flame retardant auxiliary inorganic particles of this embodiment.

[0013] (1-3) (i) Halogenated epoxy resins are epoxy resins that have been given flame retardancy through halogenation. Epoxy resins are resins with two or more epoxy groups per molecule. They are classified into two types: multifunctional epoxy resins (such as novolac epoxy resins, especially cresol novolac epoxy resins), which have an average of more than two epoxy groups per molecule, and bifunctional epoxy resins, such as bisphenol A epoxy resins, which have two epoxy groups per molecule. Multifunctional epoxy resins can form three-dimensional crosslinks when the cured product crosslinks, resulting in a stronger network. Because molecular movement is restricted even at high temperatures, they have superior heat resistance compared to bifunctional epoxy resins. For example, an example of a bifunctional epoxy resin is a resin containing a copolymer of a halogenated bisphenol derivative and epichlorohydrin. Such a halogenated bisphenol derivative is represented by the following structural formula: [ka]

[0014] (In the formula, R 1 represents a single bond or a divalent hydrocarbon group having 2 to 13 carbon atoms, and when the hydrocarbon group contains a phenyl group, the phenyl group may contain a hydroxyl group as a substituent, R 2 are the same or different and are H or CH2CH2OH, X's may be the same or different and are methyl, chlorine, or bromine, and at least one X is chlorine or bromine; n may be the same or different and is an integer of 1 to 4.)

[0015] Commercially available halogenated bisphenol derivatives include tetrabromobisphenol A: [ka] Resins copolymerized with epichlorohydrin can be obtained using this (e.g., NF series from S.K. Fine Co., Ltd., SR-T series from Sakamoto Pharmaceutical Co., Ltd.).

[0016] (ii) The number average molecular weight of the halogenated epoxy resin is preferably 1,000 to 50,000. From the viewpoint of processability, it is preferably 1,000 or more, more preferably 3,000 or more. On the other hand, from the viewpoint of safety, it is preferably 50,000 or less, more preferably 30,000 or less. The epoxy equivalent of the halogenated epoxy resin is preferably 100 to 1,000 g / equivalent. From the viewpoint of adhesion to antimony oxide, it is preferably 100 g / equivalent or more, more preferably 150 g / equivalent or more. On the other hand, from the viewpoint of pot life (epoxy group deactivation time), it is preferably 1,000 g / equivalent or less, more preferably 800 g / equivalent or less. The halogen content of the halogenated epoxy resin is preferably 1 to 50% by weight from the viewpoints of sufficient flame retardancy and cost. The melting point of the halogenated epoxy resin is preferably 50 to 350°C. From the viewpoint of melting property during processability, it is preferably 50°C or higher, and the decomposition point of the halogenated epoxy resin is preferably 300°C or higher from the viewpoint of suppressing decomposition during processing. (iii) The weight ratio of the halogen-based flame retardant (B) containing the halogenated epoxy resin to the inorganic particles of the flame retardant aid (A) is 1 / 99 to 50 / 50. From the viewpoint of flame retardancy, (B) / (A) is 1 / 99 or more, preferably 2 / 98 or more, and more preferably 3 / 97 or more, while from the viewpoint of cost, (B) / (A) is 50 / 50 or less, preferably 40 / 60 or less, and more preferably 30 / 70 or less. Furthermore, the content of the halogenated epoxy resin in the halogen-based flame retardant (B) is preferably 50% by weight or more, more preferably 70% by weight, and most preferably 100% by weight, from the viewpoint of adhesion of the halogen-based flame retardant coating. Preferred examples of halogenated flame retardants other than halogenated epoxy resins that may be contained in the halogen-based flame retardant (B) include halogenated flame retardants having a reactive group (e.g., an OH group) (e.g., tris(2,3-dibromopropyl)isocyanurate) and halogenated flame retardants having a relatively high molecular weight, for example, a number average molecular weight of 1,000 to 10,000 (e.g., brominated carbonate oligomer). (iv) At least a part of the surface of the inorganic particles of the flame retardant aid (A) is coated with one or more halogen-based flame retardants (B) containing a halogenated epoxy resin. Whether or not the flame retardant synergist granules are coated can be confirmed by measuring the contact angle of the granules with water. This is based on the fact that halogenated epoxy resins are water-repellent due to the presence of halogen substituents. More specifically, the KBr tablet method used in FT-IR measurements is applied to crush the granules to prepare a thin film of the flame retardant synergist for measurement using only the granules. The contact angle of the resulting thin film is measured using a contact angle measuring device. In order to achieve sufficient coverage with the halogen-based flame retardant (B), the contact angle with water on the surface of the thin film formed by the flame retardant auxiliary granules is preferably 90° or more, more preferably 100° or more. By being coated with one or more halogen-based flame retardants including halogenated epoxy resins, the granule surfaces have less irregularities and become smoother. Therefore, when kneading is performed using the flame retardant auxiliary granules of this embodiment, heat generation due to collisions between granules during kneading is suppressed, making mixing easier. In other words, the flame retardant auxiliary granules of this embodiment have good dispersibility. Furthermore, halogenated epoxy resins have good compatibility with many resins, which also improves dispersibility.

[0017] (1-4) In the flame retardant auxiliary granules of this embodiment, preferably, the weight ratio of (B) / (A) is set to 1 / 99 to 20 / 80 [an embodiment in which a relatively small amount of one or more halogen-based flame retardants (B) including a halogenated epoxy resin is used], thereby effectively coating the surface of the flame retardant auxiliary inorganic particles (A) and obtaining the flame retardant auxiliary granules of the present invention. Furthermore, by setting the weight ratio of (B) / (A) in the flame retardant auxiliary granules of this embodiment to more than 20 / 80 and not more than 50 / 50 (an embodiment in which a relatively large amount of one or more halogen-based flame retardants (B) including halogenated epoxy resins is used), the surface of the inorganic flame retardant auxiliary particles (A) is effectively coated, and the excess one or more halogen-based flame retardants (B) including halogenated epoxy resins function as a binder to bind the granules together, forming larger flame retardant auxiliary granules with lower bulk density. Although the flame retardant auxiliary granules of this embodiment are easily brittle, they are more preferable from the viewpoint of not breaking during handling.

[0018] (1-5) The bulk density of the coated flame retardant synergist granules is preferably 0.1 to 5.0 g / cm 3 , more preferably 0.1 to 3.0 g / cm 3 , more preferably 0.5 to 3.0 g / cm 3 , more preferably 0.5 to 2.0 g / cm 3 is. Bulk density is measured by the packed method in accordance with JIS R9301-2-3:1999 (ISO903:1976) (packed bulk density). Packed bulk density generally refers to the value obtained by dividing the mass of the granules by the volume of the granules in a container when the granules are collected by allowing them to fall freely into a stationary container of known volume and then dropping the container containing the granules from a specified height (approximately 30 mm in JIS R9301-2-3) a specified number of times (100 times in JIS R9301-2-3) to compress the granules. Furthermore, one flame-retardant auxiliary granule contains one or more inorganic particles of the flame-retardant auxiliary (A), depending on the state of the inorganic particles of the flame-retardant auxiliary (A) used as a raw material. The average maximum particle size of the flame retardant synergist granules is preferably 0.01 mm to 30 mm, and more preferably 0.1 mm to 10 mm. The average particle size here refers to the average maximum particle size of granules observed as a single, spatially separated mass, regardless of whether they are primary or secondary particles. Specifically, it can be determined by the dry dispersion method (a laser diffraction / scattering particle size distribution analyzer is used, where dry powder is dropped evenly into the measurement section using a medicine spoon or a vibrating feeder, and the granules are measured as they are without being broken).

[0019] (2) A second aspect of the present invention is (I) (A) a step of adding and mixing one or more flame-retardant auxiliary inorganic particles selected from the group consisting of flame-retardant auxiliary inorganic oxides, flame-retardant auxiliary inorganic acid salts, and flame-retardant auxiliary inorganic sulfides with (B) one or more halogen-based flame retardants including a halogenated epoxy resin, wherein the weight ratio of (B) / (A) is 1 / 99 to 50 / 50; and (II) The method for producing flame-retardant auxiliary granules includes a step of drying the granules obtained in step (I).

[0020] (2-1) In step (I), one or more halogen-based flame retardants including a halogenated epoxy resin are gradually added to the flame-retardant auxiliary particles while stirring, preferably using an internal kneader or an extruder. Preferably, the one or more halogenated flame retardants including the halogenated epoxy resin are added in the form of a solution or dispersion. The solvent used is preferably a solvent that is soluble in the one or more halogenated flame retardants including the halogenated epoxy resin and has a boiling point of 100°C or less, such as hexane. From the viewpoint of obtaining granules that are friable but not breakable during handling, the concentration of solids used is preferably 10% to 95% by weight, more preferably 15% to 90% by weight. The addition time depends on the amount of one or more halogen-based flame retardants containing halogenated epoxy resin to be added, but is preferably 1 hour or less, more preferably 0.5 hours or less, from the viewpoint of suppressing decomposition during processing. By gradually adding one or more halogenated flame retardants including halogenated epoxy resins, most of the halogenated flame retardants cover the surface of the inorganic flame retardant synergist particles until the weight ratio of (B) / (A) reaches approximately 20 / 80. When the weight ratio of (B) / (A) exceeds 20 / 80, the proportion of the added halogenated flame retardant acting as a binder for the granules formed up to that point increases, and it is thought that the granules grow into larger granules with lower bulk density.

[0021] (2-2) In step (II), the granules obtained in step (I) are dried, preferably using a cyclone dryer, etc. The preferred drying conditions are 120°C for 5 minutes.

[0022] (2-3) The one or more halogen-based flame retardants containing the halogenated epoxy resin (B) to be added may be divided into a plurality of portions, and steps (I) and (II) may be repeated a plurality of times. For example, in the first step (I), one or more halogenated flame retardants (first halogenated flame retardants) containing a halogenated epoxy resin (B) are added in a (B) / (A) weight ratio of 1 / 99 to 20 / 80, and then step (II) is carried out, followed by step (I) again to add the remaining one or more halogenated flame retardants (second halogenated flame retardants) containing a halogenated epoxy resin (B), so that the final weight ratio of (B) / (A) is 1 / 99 to 50 / 50. In this case, the content of the halogenated epoxy resin in the first halogenated flame retardant used in the first step (I) can be made different from that in the second halogenated flame retardant used in the second step (I). In the first step (I), adhesion to the surface of the inorganic particle of the flame retardant auxiliary is important, so it is preferable to use a first halogen-based flame retardant with a high content of halogenated epoxy resin, and it is more preferable that the content is 100% by weight of halogenated epoxy resin. On the other hand, in the second step (I), the second halogenated flame retardant added acts as a binder for the granules formed up to that point to a higher extent, so there is no need to increase the halogenated epoxy resin content as much as in the first step (I).By performing the second step (I), the multiple granules obtained in the first step (I) are bound together by the second halogenated flame retardant as a binder, and it is also possible to obtain granules with larger sizes and lower bulk density.

[0023] (4) A third aspect of the present invention is The flame-retardant-blended resin composition comprises the flame-retardant auxiliary granules of the first aspect of the present invention, a flame retardant, and a resin, and is characterized in that the flame-retardant auxiliary granules are present in an amount of 0.1 to 50 parts by weight per 100 parts by weight of the total amount of the resin and the flame retardant.

[0024] The flame retardant auxiliary granules of the first aspect of the present invention are versatile and have good compatibility with many resins, and can be preferably used in the preparation of flame retardant-blended resin compositions using various resins. Furthermore, recycled resins can also be used as the resins used in preparing the flame retardant-containing resin compositions, which is advantageous from the viewpoint of reducing carbon dioxide emissions.

[0025] (4-1) Any flame retardant can be used as the flame retardant, but it is preferable to use a flame retardant that exhibits a synergistic effect with the flame retardant aid used, for example, a bromine-based flame retardant when the flame retardant aid used is diantimony trioxide. Although many resins can be used, bromine-containing polymers are preferred from the viewpoint of flame retardancy. The blending composition is 0.1 to 50 parts by weight of flame retardant auxiliary granules per 100 parts by weight of the total amount of resin and flame retardant. From the viewpoint of exerting the effect of the flame retardant auxiliary, the amount is 0.1 part by weight or more, preferably 5% by weight or more. On the other hand, from the viewpoint of economy, the amount is 50% by weight or less, preferably 25% by weight or less.

[0026] (4-2) A method for preparing the composition of this embodiment can include a first step of heating and mixing the flame retardant auxiliary granules of the first embodiment of the present invention, a flame retardant, and a resin, and then a second step of molding and processing the composition obtained in the first step. From the viewpoint of cost, it is preferable to use an internal kneader or an extruder for the heating and mixing. As a molding apparatus, an internal kneader or an extruder can be preferably used. By this molding process, for example, pellet-shaped flame retardant granules can be obtained. [Example]

[0027] (1) Manufacturing flame retardant granules Flame retardant auxiliary granules of the present invention (Examples 1 to 14) and comparative examples (Comparative Examples 1 to 4) were produced using the components shown in Tables 1-1 to 1-3. Specifically, the production was basically carried out according to the following procedure. (i) In an internal kneader (device name: TD20-30 / 40, manufactured by Toshin Corporation), 10 kg (100 parts by weight) of diantimony trioxide (Sb2O3) dispersed in 5 kg of hexane was stirred, and a predetermined amount of halogenated epoxy resin and, optionally, other flame retardants (brominated carbonate oligomer or brominated triphenyl derivative) were gradually added over 1 minute (20 rpm, 60°C). After the addition was completed, the mixture was stirred for another minute, degassed with hexane, washed with steam, and then removed. (ii) The obtained granules were dried using a cyclone dryer at 120°C and an inflow velocity of 15 m / s. In Examples 13 and 14, a brominated carbonate oligomer or a brominated triphenyl derivative, which is a flame retardant other than the halogenated epoxy resin, is also added. In addition, Comparative Example 1 is a sample of diantimony trioxide itself (PATOX-M) before the above-mentioned production method is used. *1 Average particle size: 0.5 μm. [Table 1] [Table 2] [Table 3]

[0028] (2) Measurement of the physical properties of flame retardant synergist granules (2-1) The obtained flame retardant auxiliary granules of each of Examples 1 to 14 and Comparative Examples 1 to 4 were measured for coating retention rate, contact angle, bulk density (loaded bulk density), granule hardness, and airborne concentration. The results are shown in Tables 2-1 to 2-3. [Table 4] [Table 5] [Table 6]

[0029] Each measurement was carried out as follows. (Coverage maintenance rate) This is the retention rate of the coating equivalent weight of flame retardant auxiliary granules after hot toluene extraction. Here, the coating equivalent weight is the weight obtained by subtracting the weight of the inorganic flame retardant auxiliary particles in the flame retardant auxiliary granules from the weight of the flame retardant auxiliary granules. The coating retention rate is expressed as the coating equivalent weight after hot toluene extraction, expressed as % by weight, with the coating equivalent weight before hot toluene extraction being 100. The hot toluene extraction is performed using a Soxhlet extractor in accordance with Method C of JIS K6229:2015. Since one or more halogenated flame retardants including halogenated epoxy resins are considered to be soluble in hot toluene, the coverage retention rate as defined above reflects the affinity or adhesion between the inorganic flame retardant auxiliary particles and the halogenated epoxy resin. In other words, when the content of halogenated epoxy resin in the halogenated flame retardant used is constant, the higher the affinity or adhesion between the inorganic flame retardant auxiliary particles and the halogenated epoxy resin, the higher the coverage retention rate is considered to be.

[0030] (contact angle) The obtained flame-retardant auxiliary granules were compressed and tableted in a tablet press to prepare a thin film of flame-retardant auxiliary granules for measurement, based on the KBr tablet method used in FT-IR measurements (but without using KBr). More specifically, the required amount of flame-retardant auxiliary granules was crushed in an agate mortar, and the obtained powder was placed in a tablet press and tableted. The contact angle of the obtained thin film with deionized water was measured using a contact angle measuring device (device: fully automatic contact angle meter DSA30 manufactured by KRUSS) (θ / 2 method).

[0031] (bulk density) It was measured by the packed bulk method in accordance with JIS R9301-2-3:1999 (ISO903:1976) (packed bulk density). More specifically, it was measured by the packed bulk density method in accordance with JIS R9301-2-3:1999 (ISO903:1976). 3 The flame retardant assistant granules were allowed to fall freely into a (de-ionized stainless steel) container, and then collected. The container containing the flame retardant assistant granules was then dropped 100 times from a predetermined height (approximately 30 mm) to compress the flame retardant assistant granules. The bulk density was determined by dividing the total mass of the flame retardant assistant granules by the volume of the flame retardant assistant granules in the container.

[0032] (granule hardness) A compression test was performed using a texture analyzer (TA.XTplusC, manufactured by Stable Micro Systems) to measure the force required to break the cross section of a single granule (breaking strength). The force measured was the force immediately before the cross section of the granule broke. The measurement was carried out by first passing the granules through a plain weave wire mesh of mesh 2 (wire diameter 2), and then sorting the remaining granules through a plain weave wire mesh of mesh 4 (wire diameter 2).From these, one granule that was as flat or columnar as possible, suitable for the compression test, was taken out, and this single flame retardant auxiliary granule was measured on the stage above the measurement section of the device.

[0033] (Scattered concentration) The concentration was determined by atomic absorption spectrometry (equipment: Hitachi Z-5010). The element to be measured is vaporized (atomized) into atoms, which are then irradiated with light of a wavelength specific to the element to transition the ground state atoms to an excited state, and the element concentration is measured from the absorption of this light (absorbance). A calibration curve is created using elemental standard solutions of known concentrations, and quantification is performed using the calibration curve method. The values ​​in the table are converted to diantimony trioxide. Specifically, referring to Articles 36-36-4 of the Ordinance on Prevention of Harm from Specified Chemical Substances, 4 ml of hydrochloric acid and 1 ml of hydrogen peroxide were added to the membrane filter from which the sample had been collected, and the mixture was heated at approximately 90°C for 30 minutes. After cooling, 3% hydrochloric acid was added to bring the volume to 10 ml. Measurement conditions: measurement wavelength 217.63 nm, temperature conditions: 80 to 120°C, drying for 60 seconds, sample injection amount 10 μl. At this time, the calibration curve was adjusted with an acid solution (3% hydrochloric acid).

[0034] (2-2) The results in Tables 2-1 to 2-3 show that the flame retardant synergist granules of the examples, in which the content of the flame retardant synergist diantimony trioxide is in the range of 99.0 to 50.0 wt%, have a contact angle of 90° or more, are sufficiently coated with the halogen-based flame retardant, and the airborne concentration is kept very low.Furthermore, they have a relatively low and appropriate bulk density and granule hardness, which makes them easy to process.The results of the coating retention rate also confirm the adhesion of the coating. In contrast, looking at the comparative examples in which the content of the flame retardant aid diantimony trioxide is outside the range of the present invention, Comparative Example 1, which lacks a halogen-based flame retardant (halogenated epoxy resin), or Comparative Examples 2 and 4, which contain only a small amount, has a high airborne concentration and insufficient coating retention. Comparative Example 3, in which an excessive amount of a halogen-based flame retardant (halogenated epoxy resin) is added, has a high coating retention, but the bulk density and granule hardness are too high, resulting in poor processing workability.

[0035] (3) Preparation and evaluation of flame retardant-containing resin compositions Using the components shown in Tables 3-1 to 3-3, pellets of flame retardant-blended resin compositions of the present invention (Examples 15 to 23) and comparative examples (Comparative Examples 5 to 13) were produced. Specifically, the production was basically carried out according to the following procedure. In an internal kneader (device name: TD20-30 / 40, manufactured by Toshin Corporation), the resin, flame retardant aid (including flame retardant aid granules), and halogenated flame retardant were added and mixed under heating at 60°C for 1 minute. Pellets were then prepared using a crusher KGC350, manufactured by Kawata Corporation. [Table 7] [Table 8] [Table 9]

[0036] (4) Measurement of physical properties of flame retardant-containing resin compositions The resulting pellets of the flame retardant-blended resin compositions of Examples 15 to 23 and Comparative Examples 5 to 13 were subjected to measurements of fluidity, flexural modulus, Charpy impact strength, and heat release rate during the UL-94 combustion test. The results are shown in Tables 4-1 to 4-3. [Table 10] [Table 11] [Table 12]

[0037] Each measurement was carried out as follows.

[0038] (Liquidity) The melt mass flow rate (MFR) was measured based on JIS K 7210-1:2014 (ISO 1133-1:2011). The melted flame retardant granule-blended resin composition was extruded from the cylinder of a melt indexer (G-Melt, manufactured by Toyo Seiki Seisakusho) under the specified temperature (220 or 250°C) and load (5 kg), and the extrusion melt rate was calculated in grams per 10 minutes (g / 10 min).

[0039] (flexural modulus) The flexural modulus of the flame retardant granule-containing resin composition was measured using an injection molding machine (NEX500-5E, manufactured by Nissei Plastic Industrial Co., Ltd.) based on K7171:2016 (ISO 178:2010, Amd.1:2013).

[0040] (Charpy impact strength) The flame retardant-blended resin composition was injection molded to prepare notched test specimens in accordance with K7111-1:2012, which was created based on ISO179-1, and the impact energy absorbed at the time of breakage was calculated as the value divided by the initial cross-sectional area of ​​the test specimen. Generally, if the dispersion is good, the Charpy impact strength increases, and if there is aggregation, the strength tends to decrease.

[0041] (heat generation rate) Test specimens were prepared from the flame retardant-blended resin composition by injection molding in accordance with UL94 / IEC60695-11-10 / JIS K6911. The heat release rate (W) of the test specimens during combustion was measured using a UL-94V vertical combustion tester (multi-calorie meter, manufactured by Toyo Seiki Seisakusho) that is capable of measuring the heat release rate. [Industrial Applicability]

[0042] The preferred flame retardant synergist granules of the present invention have good dispersibility, making them ideal for use in electrical and electronic products, where preventing dimensional distortion is particularly important. Holes in product housings have specified screw-fastening dimensions, and when environmental changes cause gradual crystallization, dimensional changes occur, resulting in localized stress at the screw-fastening points and damage such as cracks. In particular, in optical components, dimensional distortion can affect image characteristics and cause fatal damage. The flame retardant synergist granules of the present invention can contribute to improving the dimensional accuracy of components. Furthermore, the flame-retardant auxiliary granules of the present invention can be used in a wide range of applications, not limited to electrical and electronic products, such as aerospace, vehicles, medical care, leisure, etc. In particular, they are useful as a flame-retardant restoring agent for flame-retardant resins whose flame retardancy has been reduced due to recycling.

Claims

1. A flame retardant synergist granule comprising: (A) one or more flame retardant synergist inorganic particles selected from the group consisting of a flame retardant synergist inorganic oxide, a flame retardant synergist inorganic acid salt, and a flame retardant synergist inorganic sulfide; and (B) one or more halogen-based flame retardants including a halogenated epoxy resin, the weight ratio of (B) / (A) is 1 / 99 to 50 / 50; At least a portion of the surface of the (A) flame retardant auxiliary inorganic particles is coated with (B) one or more halogen-based flame retardants including a halogenated epoxy resin; Flame retardant auxiliary granules, the bulk density of which is measured by the pile method in accordance with JIS R9301-2-3:1999, is 0.1 to 3.0 g / cm 3 .

2. 2. The flame retardant synergist granule according to claim 1, wherein the weight ratio of (B) / (A) is 1 / 99 to 20 / 80.

3. 2. The flame retardant synergist granule according to claim 1, wherein the weight ratio of (B) / (A) is greater than 20 / 80 and less than 50 / 50.

4. 2. The flame retardant synergist granule according to claim 1, wherein the inorganic flame retardant synergist particles (A) are one or more selected from the group consisting of antimony oxide, antimonate, zinc sulfide, zinc borate, zinc stannate, and activated alumina.

5. The flame-retardant auxiliary granule according to claim 4, wherein the inorganic particles of the flame-retardant auxiliary (A) are diantimony trioxide.

6. The flame retardant auxiliary granule according to any one of claims 1 to 5, wherein the halogenated epoxy resin has a number average molecular weight of 1,000 to 50,000 and an epoxy equivalent of 100 to 1,000 g / equivalent.

7. 7. The flame retardant auxiliary granule according to claim 6, wherein the halogen content of the halogenated epoxy resin is 30 to 60% by weight.

8. A flame retardant aid granule described in any one of claims 1 to 7, wherein a flame retardant aid granule thin film prepared by crushing the flame retardant aid granules and pressurizing them into tablets in accordance with the KBr tablet method has a contact angle with deionized water of 90° or more.

9. (I) (A) a step of adding and mixing one or more flame retardant auxiliary inorganic particles selected from the group consisting of flame retardant auxiliary inorganic oxides, flame retardant auxiliary inorganic acid salts, and flame retardant auxiliary inorganic sulfides, with (B) one or more halogen-based flame retardants including a halogenated epoxy resin, wherein the weight ratio of (B) / (A) is 1 / 99 to 50 / 50; and (II) A method for producing flame-retardant auxiliary granules, comprising a step of drying the granules obtained in step (I), The production method, wherein the bulk density of the flame retardant auxiliary granules measured by the pile method in accordance with JIS R9301-2-3:1999 is 0.1 to 3.0 g / cm 3 .

10. A flame-retardant-blended resin composition comprising the flame-retardant auxiliary granules of claim 1, a flame retardant, and a resin, wherein the flame-retardant auxiliary granules are present in an amount of 0.1 to 50 parts by weight per 100 parts by weight of the total amount of the resin and the flame retardant.

11. The flame retardant-containing resin composition according to claim 10, wherein the resin is a recycled resin.

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