Flame-retardant resin composition

Abstract

The flame-retardant resin composition of the present invention contains a thermosetting resin and a flame retardant, and has a ΔEr of 30 or less obtained according to the following procedure. Procedure: (i) Using the flame-retardant resin composition, a test plate (size 120 mm square, thickness 2 mm) is produced under the conditions of a mold temperature of 175°C and a curing time of 3 minutes. (ii) A torch burner (30 mm relative to the flame length of about 100 mm) is aligned so as to contact the flame at an angle of 90° relative to the test plate, and is brought into contact with the flame for 5 minutes at the center of one face of the vertically placed test plate. (iii) The color difference before and after contact with the flame is measured for the center of the other face of the test plate and for 2 points on a straight line passing through the center of the other face and 3 mm distant from the center, and the average value (ΔEr) is obtained.

Description

Technical Field

[0001] This invention relates to flame-retardant resin compositions. More specifically, it relates to flame-retardant resin compositions and vehicle components comprising cured flame-retardant resin compositions. Background Technology

[0002] In recent years, from an environmental protection perspective, the development of electric vehicles or hybrid vehicles powered by electric motors has become increasingly popular. In battery packs installed in such electric vehicles or hybrid vehicles, there is a possibility that a fire in one of the multiple batteries can cause adjacent batteries to catch fire in succession. Therefore, for example, Patent Document 1 (Japanese Patent Application Publication No. 2023-146688) discloses a method of covering the outside of a battery housing casing with a resin containing a flame retardant.

[0003] On the other hand, as one of the techniques to improve the flame retardancy of resin compositions, examples have been proposed that include compounds known as flame retardants. Examples of flame retardants used in resin compositions include inorganic flame retardants such as metal hydroxides (for example, see Patent Document 2 (International Publication No. 2020 / 080149)).

[0004] Previously, the UL94 standard was known as one of the indicators of flame retardancy. The UL94 standard is widely used worldwide to evaluate the flame retardancy of plastic products. The UL94 standard has levels of flame retardancy from highest to lowest: 5VA, 5VB, V-0, V-1, V-2, and HB. For example, in the V-0 test, two 10-second exposures to a flame are conducted.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2023-146688

[0008] Patent Document 2: International Publication No. 2020 / 080149 Summary of the Invention

[0009] The technical problem that the invention aims to solve

[0010] With increasing safety awareness and higher demands for performance, the requirements for the flame retardancy of flame retardants are becoming increasingly stringent. Therefore, there is room for improvement in achieving higher flame retardancy in conventional flame retardants as disclosed in Patent Documents 1 and 2.

[0011] Means for solving technical problems

[0012] The inventors conducted in-depth research to achieve higher flame retardancy and determined that even with good flame retardancy based on the UL94 standard, the flame retardancy is insufficient under prolonged exposure to flame or under stronger flame conditions. Furthermore, further research revealed that it is effective to propose new flame retardancy indicators and manufacture flame-retardant resin compositions in a manner that meets these indicators, thus completing this invention.

[0013] According to the present invention, the following flame-retardant resin compositions and related technologies can be provided.

[0014] [1] A flame-retardant resin composition comprising a thermosetting resin and a flame retardant, wherein the flame-retardant resin composition is characterized in that:

[0015] The ΔEr obtained by following the steps below is below 30.

[0016] step:

[0017] (i) Using the flame-retardant resin composition, a test panel (120 mm square, 2 mm thick) was prepared at a mold temperature of 175 °C and a curing time of 3 minutes.

[0018] (ii) Align the torch burner (30 mm relative to the flame length of approximately 100 mm) with the center of one face of the vertically placed test plate at an angle of 90° relative to the test plate and expose it to the flame for 5 minutes.

[0019] (iii) For the center of the other side of the test plate and two points 3 mm away from the center on a straight line passing through the center of the other side, measure the color difference before and after contact with the flame, and calculate the average value (ΔEr).

[0020] [2] The flame-retardant resin composition according to [1] is characterized in that:

[0021] The flame retardant comprises one or more selected from organic and inorganic flame retardants.

[0022] [3] The flame-retardant resin composition according to [1] or [2] is characterized in that:

[0023] It also contains inorganic filler materials.

[0024] [4] The flame-retardant resin composition according to any one of [1] to [3], characterized in that:

[0025] For the center of one side of the test plate obtained in step (ii), and two points 3 mm away from the center on a straight line passing through the center of the one side, the color difference before and after contact with the flame is measured, and the average value (ΔEf) is calculated. ΔEf is 0 to 100.

[0026] [5] The flame-retardant resin composition according to any one of [1] to [4], characterized in that:

[0027] The content of the flame retardant is 1 to 45 parts by weight relative to 100 parts by weight of the flame retardant resin composition.

[0028] [6] The flame-retardant resin composition according to any one of [1] to [5] is characterized in that:

[0029] The thermosetting resin comprises one or more selected from phenolic resin, diallyl phthalate resin, unsaturated polyester resin, epoxy resin, melamine resin and furan resin.

[0030] [7] The flame-retardant resin composition according to [3] is characterized in that:

[0031] The inorganic filler material is selected from one or more of the following: fiber fillers, plate fillers, and spherical fillers.

[0032] [8] The flame-retardant resin composition according to [3] or [7] is characterized in that:

[0033] The inorganic filler material is selected from one or more of glass fiber, carbon fiber, metal fiber and mineral filler.

[0034] [9] The flame-retardant resin composition according to [3] or [7] or [8] is characterized in that:

[0035] The content of the inorganic filler material is 30 to 85 parts by weight relative to 100 parts by weight of the flame-retardant resin composition.

[0036]

[10] The flame-retardant resin composition according to any one of [1] to [9], characterized in that:

[0037] Using this flame-retardant resin composition, test panels (125mm × 13mm in size and 0.75mm in thickness) were prepared at a mold temperature of 175°C and a curing time of 3 minutes. In tests conducted according to UL-94 standards, the panel met the V-1 standard of UL-94.

[0038]

[11] The flame-retardant resin composition according to any one of [1] to

[10] is characterized in that:

[0039] The flame-retardant resin composition can be used in automotive components.

[0040]

[12] A cured product, characterized in that it is a cured product of the flame-retardant resin composition described in any one of [1] to

[11] .

[0041]

[13] A vehicle component, characterized in that: it comprises a cured product of the flame-retardant resin composition described in

[11] .

[0042] Invention Effects

[0043] According to the present invention, a flame-retardant resin composition with improved flame retardancy can be provided. Attached Figure Description

[0044] Figure 1 This is a photographic image showing the results of the flame retardancy evaluation of the test plate in Example 1.

[0045] Figure 2 This is a photographic image showing the results of the flame retardancy evaluation of the test plate in Example 2.

[0046] Figure 3 This is a photographic image showing the results of the flame retardancy evaluation of the test plate of Comparative Example 1.

[0047] Figure 4 This is a photographic image showing the results of the flame retardancy evaluation of the test plate of Comparative Example 2. Detailed Implementation

[0048] The embodiments of the present invention will now be described in detail.

[0049] In this specification, the expression "a~b" in the description of numerical ranges means "a to b" unless otherwise specified. For example, "1~5 mass%" means "1 mass% to 5 mass%".

[0050] <Flame-retardant resin composition>

[0051] The flame-retardant resin composition of this embodiment comprises a thermosetting resin and a flame retardant, and the ΔEr obtained by the following steps is 30 or less.

[0052] step:

[0053] (i) Using the flame-retardant resin composition, a test panel (120 mm square, 2 mm thick) was prepared at a mold temperature of 175 °C and a curing time of 3 minutes.

[0054] (ii) Align the torch burner (30 mm relative to the flame length of approximately 100 mm) with the center of one face of the vertically placed test plate at an angle of 90° relative to the test plate and expose it to the flame for 5 minutes.

[0055] (iii) For the center of the other side of the test plate and two points 3 mm away from the center on a straight line passing through the center of the other side, measure the color difference before and after contact with the flame, and calculate the average value (ΔEr).

[0056] Therefore, the flame retardancy of the flame-retardant resin composition can be effectively improved. In other words, ΔEr is a new indicator proposed by the inventors, and high flame retardancy can be obtained by manufacturing the flame-retardant resin composition in a manner that satisfies this indicator.

[0057] Here, as one of the indicators of flame retardancy, the UL94 standard can be cited as an example. The heat capacity of the burner used in V-0 of this standard is 0.05 kW, while the heat capacity of the torch burner used in step (ii) of this embodiment is 2 to 4 kW. Furthermore, ΔEr is the color difference at three specified points on the non-flame-contact surface of the test plate before and after contact with the flame. That is, a low ΔEr value indicates that the discoloration on the back side of the test plate is small before and after the surface of the test plate is exposed to the flame, which means that the test plate is not easily combustible relative to the flame. In other words, with low flame retardancy, the flame and heat easily reach the back side (non-flame-contact surface), and the discoloration and ash formation on the back side of the test plate will be greater.

[0058] Therefore, the flame-retardant resin composition of this embodiment, by controlling ΔEr obtained according to the above steps, achieves high flame retardancy against higher heat flames from a different perspective than before.

[0059] ΔEr is 30 or less, preferably 25 or less, and more preferably 22 or less.

[0060] By setting ΔEr below the aforementioned upper limit, higher flame retardancy can be achieved.

[0061] Furthermore, when measuring the color difference before and after contact with the flame at the center of one side of the test plate obtained in step (ii) and at two points 3 mm away from the center on a straight line passing through the center of the one side, and calculating the average value (ΔEf), ΔEf is preferably 1 to 100, more preferably 10 to 80, and even more preferably 20 to 70.

[0062] By setting ΔEf below the aforementioned upper limit, flame retardancy becomes good.

[0063] That is, ΔEf is the color difference at three specified points on the flame-contacted surface of the test plate before and after contact with the flame. In other words, a low ΔEf value indicates that the surface of the test plate changes color less before and after contact with the flame, which means that the test plate is not easily combustible relative to the flame.

[0064] In addition, in (ii) above, the torch burner is directed toward the center point of the test plate so that it contacts the flame, and the flame in contact with the test plate can have an extension of approximately 20 mm (about 40 mm in diameter) from the center point.

[0065] Furthermore, in (iii) above, the color difference is measured at three points: the center of the test plate and two symmetrical points 3 mm away from the center. The color difference is measured after the test plate has returned to room temperature following contact with the flame.

[0066] ΔE (ΔEr and ΔEf) can be achieved by adjusting the selection and formulation of materials constituting the flame-retardant resin composition, and by focusing on the manufacturing method. Details will be explained later; for example, the selection of organic flame retardants, the choice of inorganic fillers, the adjustment of the ratio of inorganic fillers to thermosetting resins, and the control of the number of roller mixing cycles when mixing the materials can be cited.

[0067] In addition, color difference (ΔE) was measured in the following manner.

[0068] For the established measurement points, a colorimeter was used to measure the values ​​according to CIE 1976L. * a * b * The color coordinates (L) specified in the color system are... * a * b * The chromaticity coordinates measured on the test plate before contact with the flame are set as (L). * 0, a * 0, b * 0), set the chromaticity coordinates measured in the test plate after contact with the flame as (L * 1, a * 1, b * 1), and by substituting the obtained values ​​into the following formula, ΔE can be calculated.

[0069] ΔEr=〔(L * 1-L * 0) 2 +(a * 1-a * 0) 2 +(b * 1-b * 0) 2 ] 1 / 2

[0070] Furthermore, the flame-retardant resin composition of this embodiment preferably meets the V-1 standard of UL-94. This allows for a more stable and high flame retardancy. Specifically, using the flame-retardant resin composition of this embodiment, test panels (125mm × 13mm in size, 0.75mm in thickness) were prepared at a mold temperature of 175°C and a curing time of 3 minutes, and tested according to the UL-94 standard.

[0071] The components constituting the flame-retardant resin composition are described below.

[0072] [Flame retardant]

[0073] Flame retardants are compounds used to impart flame retardancy to thermosetting resins.

[0074] Flame retardants can be classified into organic flame retardants and inorganic flame retardants based on their composition. In the flame-retardant resin composition of this embodiment, organic flame retardants, inorganic flame retardants, and mixtures thereof can be used.

[0075] (Organic flame retardant)

[0076] Examples of organic flame retardants include phosphorus-based flame retardants, organosilicon-based flame retardants, and halogen-based flame retardants. Among these, phosphorus-based and organosilicon-based flame retardants are preferred as organic flame retardants.

[0077] Phosphorus-based flame retardants form char when burned.

[0078] Examples of phosphorus-based flame retardants include red phosphorus; phosphate esters such as trimethyl phosphate (TMP), triethyl phosphate (TEP), triphenyl phosphate (TPP), trimethylbenzene phosphate (TXP), tributyl phosphate (TBP), trimethylbenzene phosphate (TCP), and toluene diphenyl phosphate (CDP); halogenated organic phosphoric acid systems such as tri(2-chloroethyl) phosphate (TCEP), tri(1-chloro-2-propyl) phosphate (TCPP), and tri(1,3-dichloro-2-propyl) phosphate (TDCPP); polyphosphoric acid systems such as polychlorophosphonates and ammonium polyphosphate (APP); and polyinorganic phosphoric acid systems.

[0079] Organosilicon compounds, as organosilicon-based flame retardants, can improve flame retardancy through chemical reactions during combustion. Examples of organosilicon compounds include one or more selected from silicone resins, silicone rubbers, silicone oils, etc.

[0080] As organosilicon compounds, examples include those that can convert SiO2, R-SiO2, etc. 3 / 2 R-SiO, R-SiO 1 / 2Resins and the like that are formed by combining structural units to create a three-dimensional network structure. Additionally, R represents alkyl groups such as methyl, ethyl, and propyl; aromatic groups such as phenyl and benzyl; and the substituents include vinyl substituents.

[0081] Organosilicon compounds can be linear or branched. Furthermore, the organic residues bonded to silicon atoms are preferably organic residues with 1 to 30 carbon atoms, more preferably 1 to 20. Specifically, examples of such organic residues include alkyl groups such as methyl, ethyl, propyl, butyl, hexyl, and decyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl; and aralkyl groups such as tolyl. More preferably, they are alkyl, alkenyl, or aryl groups with 1 to 8 carbon atoms.

[0082] (Inorganic flame retardant)

[0083] Inorganic flame retardants may include one or more selected from metal hydroxide flame retardants, boron flame retardants, and antimony oxide flame retardants.

[0084] Metal hydroxide flame retardants produce little smoke during combustion and can release water at high temperatures. Examples of metal hydroxide flame retardants include one or more selected from magnesium hydroxide, aluminum hydroxide, barium hydroxide, and calcium hydroxide.

[0085] As boron-based flame retardants, one or more can be selected from calcium borate and zinc borate.

[0086] As antimony oxide-based flame retardants, one or more of antimony trioxide and antimony pentoxide can be cited.

[0087] Among them, magnesium hydroxide, aluminum hydroxide and zinc borate are preferred as inorganic flame retardants.

[0088] The content of the flame retardant relative to 100 parts by weight of the flame retardant resin composition is preferably 1 to 45 parts by weight, more preferably 2 to 40 parts by weight, and even more preferably 3 to 35 parts by weight.

[0089] By setting the flame retardant content above or below the aforementioned lower limit, flame retardancy can be easily improved. On the other hand, by setting the flame retardant content below or below the aforementioned upper limit, the functions of the thermosetting resin can be easily utilized while maintaining flame retardancy.

[0090] When using an organic flame retardant, its content relative to 100 parts by weight of the flame retardant resin composition is preferably 1 to 20 parts by weight, more preferably 2 to 15 parts by weight, and even more preferably 3 to 10 parts by weight.

[0091] By setting the content of the organic flame retardant above or above the aforementioned lower limit, flame retardancy can be easily improved. On the other hand, by setting the content of the organic flame retardant below or below the aforementioned upper limit, the functions of the thermosetting resin can be easily utilized while maintaining flame retardancy.

[0092] When using an inorganic flame retardant, its content relative to 100 parts by weight of the flame retardant resin composition is preferably 10 to 45 parts by weight, more preferably 15 to 40 parts by weight, and even more preferably 18 to 35 parts by weight.

[0093] By setting the content of the inorganic flame retardant to the lower limit or above mentioned above, flame retardancy can be easily improved. On the other hand, by setting the content of the inorganic flame retardant to the upper limit or below mentioned above, the function of the thermosetting resin can be easily utilized while maintaining flame retardancy.

[0094] (Thermosetting resin)

[0095] Examples of thermosetting resins include one or more selected from phenolic resins, diallyl phthalate resins, unsaturated polyester resins, epoxy resins, melamine resins, and furan resins. Among these, phenolic resins are preferred.

[0096] Specifically, examples of the aforementioned phenolic resins include phenolic varnish-type phenolic resins, methyl phenolic resins, and arylalkylene-type phenolic resins. These phenolic resins can be used alone, or two or more of them with different weight-average molecular weights can be used simultaneously, or one or more of them can be used simultaneously with their prepolymers. Among these, methyl phenolic resins are preferred.

[0097] The aforementioned diallyl phthalate resin is a prepolymer synthesized from diallyl phthalate monomers or diallyl isophthalate monomers. Depending on whether the monomer is a phthalic acid monomer or an isophthalic acid monomer, there are diallyl phthalate resins and diallyl isophthalate resins.

[0098] By using diallyl phthalate, which is an ester of phthalic acid and allyl alcohol, as a constituent monomer and has a structure polymerized in the allyl group of diallyl phthalate, especially by using diallyl isophthalic acid, the heat resistance can be improved.

[0099] Furthermore, by suppressing the content of diallyl isophthalate resin to a relatively low level and increasing the content of aluminum hydroxide, the tracking resistance can be improved, thereby achieving both tracking resistance and flame retardancy at a higher level.

[0100] In this embodiment, the diallyl isophthalate resin, in addition to a substance comprising diallyl isophthalate as an ester of isophthalic acid and allyl alcohol as a constituent monomer and having a structure polymerized in the allyl group of diallyl isophthalate, also comprises a substance in which at least a portion of the diallyl isophthalate as a constituent monomer is replaced by a compound wherein at least a portion of the hydrogen atoms on the benzene ring of isophthalic acid is replaced by halogen atoms such as chlorine or bromine, or a compound in which all or part of the unsaturated bonds present in the molecule of diallyl isophthalate or the molecule substituted with diallyl isophthalate are hydrogenated.

[0101] Specific examples of epoxy resins include, for instance, biphenyl-type epoxy resins; bisphenol-type epoxy resins such as bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, bisphenol AD-type epoxy resin, and tetramethylbisphenol F-type epoxy resin; zirconia-type epoxy resins; phenolic varnish-type epoxy resins such as phenolic varnish-type epoxy resin and cresolic varnish-type epoxy resin; triphenyl-type epoxy resins such as triphenol-methane-type epoxy resin and alkyl-modified triphenol-methane-type epoxy resin; and multifunctional epoxy resins such as phenolic aralkyl-type epoxy resin with a phenylene backbone, naphtholic aralkyl-type epoxy resin with a phenylene backbone, and biphenyl-type epoxy resin with a phenylene backbone. Phenolic alkyl alkyl type epoxy resins include phenolic alkyl type epoxy resins (biphenyl alkyl type epoxy resins) and naphthol alkyl alkyl type epoxy resins with a biphenyl-like backbone; naphthol type epoxy resins include dihydroxynaphthalene type epoxy resins and epoxy resins obtained by glycidyl etherification of dihydroxynaphthalene dimers; triazine core-containing epoxy resins include triglycidyl isocyanurate and monoallyl isocyanurate diglycidyl isocyanurate; bridged cyclic hydrocarbon modified phenol type epoxy resins include dicyclopentadiene modified phenol type epoxy resins; brominated type epoxy resins include brominated bisphenol A type and brominated phenolic varnish type; and tris(hydroxyphenyl)methane type epoxy resins. As epoxy resins, one of these can be used alone, or two or more different types can be used simultaneously.

[0102] As an unsaturated polyester resin, specifically, a thermosetting resin obtained by reacting unsaturated dicarboxylic acids such as maleic anhydride and saturated dicarboxylic acids such as phthalic anhydride with diols can be cited. It is usually used in the form of a polymeric monomer such as styrene.

[0103] More specifically, regarding unsaturated polyester resins, examples include one or more phthalic acid-based unsaturated polyester resins selected from ortho, meta, and para types. The ortho type is obtained by reacting phthalic anhydride or phthalic acid with a glycol as raw materials to form a condensation reaction. The meta type is obtained by reacting isophthalic acid with a glycol to form a condensation reaction. The para type is obtained by reacting terephthalic acid with a glycol to form a condensation reaction.

[0104] The unsaturated polyester resin is preferably one or more phthalic acid-based unsaturated polyester resins selected from the para-type obtained by reacting terephthalic acid with a diol and the meta-type obtained by reacting isophthalic acid with a diol.

[0105] The unsaturated polyester resin may include, for example, at least one of the para-type and meta-type phthalic acid-based unsaturated polyester resins described above. Alternatively, the unsaturated polyester resin may include both the para-type and meta-type phthalic acid-based unsaturated polyester resins described above. When the unsaturated polyester resin includes both para-type and meta-type phthalic acid-based unsaturated polyester resins, the proportion of the meta-type resin relative to the total of 100 parts by mass of the para-type and meta-type resins is, for example, 40 parts by mass or more, or 50 parts by mass or more, or 55 parts by mass or more, or specifically, less than 100 parts by mass, or for example, less than 80 parts by mass.

[0106] The content of thermosetting resin relative to 100 parts by weight of flame retardant resin composition is preferably 10 to 50 parts by weight, more preferably 15 to 45 parts by weight, and even more preferably 20 to 38 parts by weight.

[0107] By setting the content of thermosetting resin to the lower limit mentioned above, good flame retardancy and processability can be achieved.

[0108] By keeping the content of thermosetting resin below the aforementioned upper limit, it is easier to achieve the UL-94 standard at a high level while maintaining flame retardancy against high-heat flames.

[0109] [Inorganic filler materials]

[0110] The flame-retardant resin composition may also contain inorganic fillers.

[0111] Inorganic filler materials are inorganic materials other than the aforementioned inorganic flame retardants, and are used from the viewpoint of improving the mechanical strength of the cured flame-retardant resin composition and improving its flame retardancy.

[0112] The inorganic filler material, depending on its shape, is preferably selected from one or more of the following: fiber fillers, plate fillers, and spherical fillers.

[0113] The fiber filler is a short fiber, and may be selected from one or more of metal fibers, carbon fibers, glass fibers, and ceramic fibers. Among them, metal fibers, carbon fibers, and glass fibers are preferred, and glass fibers are more preferred.

[0114] Plate-shaped packings can be, for example, packings with an aspect ratio of 3 or higher, while spherical packings are perfectly round or nearly perfectly round, for example, packings with an aspect ratio of less than 3.

[0115] Examples of materials that can be used as constituent materials for spherical or plate-shaped fillers include minerals such as talc, mica, halloysite, kaolin, illite, montmorillonite, vermiculite, palygorskite, pyrophyllite, bedesulfurite, chloropyroxene, soapstone, lithium montmorillonite, zinc montmorillonite, calcium silicate, aluminum silicate, wollastonite, glass flakes, and molybdenum sulfide; sulfates such as potassium sulfate, aluminum sulfate, sodium sulfite, calcium sulfate, and barium sulfate; carbonates such as calcium carbonate and magnesium carbonate; metal oxides such as alumina; crystalline or fused silica, surface-treated silica; and glass beads. These can be used individually or in combination of two or more. For example, fiber fillers and plate-shaped fillers can be used in combination.

[0116] The content of inorganic filler material relative to 100 parts by weight of the flame-retardant resin composition is preferably 30 to 85 parts by weight, more preferably 35 to 80 parts by weight, and even more preferably 38 to 75 parts by weight.

[0117] By setting the content of inorganic filler material above the aforementioned lower limit, it is possible to obtain flame retardancy based on the UL94 standard while also improving flame retardancy relative to its high heat output.

[0118] On the other hand, by keeping the content of inorganic filler material below the aforementioned upper limit, good flame retardancy against high heat can be obtained.

[0119] [other]

[0120] Furthermore, flame-retardant resin compositions may contain known compounds, depending on the application.

[0121] Examples of well-known compounds include, for instance, curing aids, polymerization initiators, polymerization inhibitors, curing agents, coupling agents, surfactants, curing accelerators, elastomers, pigments, and adhesion enhancers. These may contain only one type or more.

[0122] (Curing aid)

[0123] As curing aids, examples include those known in the field of resin compositions. Examples include oxides or hydroxides of alkaline earth metals such as magnesium oxide, calcium hydroxide, and barium hydroxide; and aromatic carboxylic acids such as salicylic acid and benzoic acid. These alkaline earth metal oxides or hydroxides can also be used as inorganic flame retardants.

[0124] When using a curing aid, the content of the curing aid relative to 100 parts by weight of the thermosetting resin is preferably 1 to 10 parts by weight, for example.

[0125] (Polymerization initiator)

[0126] Polymerization initiators are used to initiate polymerization. Organic peroxides are preferred as polymerization initiators.

[0127] As an organic peroxide, examples include one or more selected from ketone peroxides, peroxy ketals, hydroperoxides, hydroxyperoxides, diallyl peroxides, diacyl peroxides, peroxy esters, and peroxy dicarbonates.

[0128] When using a polymerization initiator, the content of the polymerization initiator relative to 100 parts by weight of the thermosetting resin is preferably 1 to 10 parts by weight, and more preferably 1 to 5 parts by weight.

[0129] (Curing agent)

[0130] The curing agent can be selected based on the type of thermosetting resin; there are no particular limitations as long as it can react with it. Specifically, examples of curing agents include addition-polymerization type curing agents, catalyst-type curing agents, and condensation-type curing agents.

[0131] Specifically, curing agents can include phenolic curing agents; amines; polyhydroxystyrene such as poly(p-hydroxystyrene); alicyclic anhydrides such as hexahydrophthalic anhydride (HHPA) and methyltetrahydrophthalic anhydride (MTHPA), and aromatic anhydrides such as trimellitic anhydride (TMA), pyromellitic dianhydride (PMDA), and benzophenone tetracarboxylic dianhydride (BTDA); polysulfides, thioesters, thioethers, and other polythiols; isocyanate prepolymers, end-capped isocyanates, and other isocyanate compounds; organic acids such as carboxylic acid-containing polyester resins; and hexamethylenetetramine, etc. One or more of these can be used.

[0132] The content of thermosetting resin and curing agent can be appropriately set according to the type of thermosetting resin and curing agent.

[0133] (Coupled agent)

[0134] In the case of containing inorganic fillers, coupling agents may also be included. This helps to suppress the aggregation of inorganic fillers and achieve good flowability.

[0135] As coupling agents, various known coupling agents such as epoxysilanes, mercaptosilanes, aminosilanes, alkylsilanes, ureosilanes, vinylsilanes, titanium compounds, aluminum chelates, and aluminum / zirconium compounds can be used.

[0136] (Elastomer)

[0137] Examples of elastomers include acrylonitrile butadiene rubber, isoprene, styrene butadiene rubber, and ethylene propylene rubber. Acrylonitrile butadiene rubber is preferred. By using elastomers, the toughness of the cured flame-retardant resin composition can be improved.

[0138] When using an elastomer, the content of the elastomer relative to 100 parts by weight of the thermosetting resin is preferably 2 to 15 parts by weight, for example.

[0139] (Mold release agent)

[0140] Examples of mold release agents include fatty acids such as stearic acid, fatty acid salts such as calcium stearate or zinc stearate, fatty acid amides, and polyethylene.

[0141] When using a release agent, the content of the release agent relative to 100 parts by weight of the thermosetting resin is, for example, 1 to 10 parts by weight, preferably 2 to 8 parts by weight.

[0142] (pigment)

[0143] Carbon black can be cited as an example of a pigment. Furthermore, various coloring pigments can be used to obtain molded articles with the desired color.

[0144] When using pigments, the amount of pigment relative to 100 parts by weight of the thermosetting resin is, for example, 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight.

[0145] Next, the method for manufacturing the flame-retardant resin composition of this embodiment will be described.

[0146] The method for manufacturing the flame-retardant resin composition of this embodiment is not particularly limited. For example, when the thermosetting component and other arbitrary components are in liquid state, they can be mixed by using a Sany motor or the like and stirring with a stirring paddle.

[0147] Alternatively, if the thermosetting component and any other components are in a solid state, they can be mixed using a mixer or similar equipment, and then melt-heated and kneaded at approximately 90–120°C using a heated kneader, heated roller, or extruder. For example, the preferred conditions for heated kneading are 20–40 roller rotations and a rotation speed of 14–20 rpm. Next, the resulting mixture is cooled and pulverized to obtain a powdered / granular resin composition. The resin composition can be pressed into tablets after pulverization, or it can be formed into sheets, for example, through vacuum lamination or compression molding.

[0148] <Molded / Curedled Products>

[0149] The molded article of this embodiment is a cured product of a flame-retardant resin composition, suitable for applications requiring flame retardancy. Specifically, examples include various structural components for transportation equipment such as automobiles, airplanes, railway vehicles, and ships; buildings; office equipment; general machinery; household appliances; and electrical equipment. It is particularly suitable as an automotive component.

[0150] The cured (fully cured) flame retardant resin composition can be achieved, for example, by heating the flame retardant resin composition at 165–175°C for 0.5–10 minutes.

[0151] The embodiments of the present invention have been described above, but these are merely examples, and various configurations other than those described above may be employed. Furthermore, the present invention is not limited to the embodiments described above, and modifications and improvements within the scope of achieving the objectives of the present invention are included in the present invention.

[0152] Example

[0153] The embodiments of the present invention will be described in detail with reference to examples and comparative examples. However, the present invention is not limited to these examples.

[0154] (1) Raw materials of flame retardant resin composition

[0155] Flame-retardant resin compositions are prepared using the following raw materials.

[0156] [raw material]

[0157] (Thermosetting resin)

[0158] • Phenolic Resin 1: A-type phenolic resin, "PR-53529", manufactured by Sumitomo Bakelite Co., Ltd.

[0159] • Diallyl isophthalate resin 1: Manufactured by Osaka Soda Co., Ltd., DAISO ISODAP, weight-average molecular weight (converted from polystyrene): 3×10 4 ~5×10 4 Iodine value: 75-90; softening point: 50℃-80℃; has a chemical structure represented by the following formula (1).

[0160]

[0161] • Diallyl phthalate resin 1: Manufactured by Osaka Soda Co., Ltd., DAISO DAP K, weight-average molecular weight (converted from polystyrene): 2×10 4 ~3×10 4 Iodine value: 50-60, softening point: 65℃-100℃, with a chemical structure represented by the following formula (2).

[0162]

[0163] • Unsaturated polyester resin 1: Unsaturated polyester resin, para-type, 8523, manufactured by Japan U-Pica Co., Ltd.

[0164] • Unsaturated polyester resin 2: Unsaturated polyester resin, meta-type, 8510, manufactured by Japan U-Pica Co., Ltd.

[0165] (Curing agent)

[0166] • Curing Agent 1: Hexamethylenetetramine (HEXAMINE), manufactured by Changchun Petrochemical Co., Ltd.

[0167] (Curing aid)

[0168] • Curing aid 1: Calcium hydroxide: “Quick lime SA074”, manufactured by Chichibu Lime Industry Co., Ltd.

[0169] (Polymerization initiator)

[0170] • Polymerization initiator 1: Organic peroxide (thermal decomposition temperature (decomposition temperature for obtaining a 1-minute half-life): 175°C)

[0171] (monomer)

[0172] • Diallyl phthalate compound 1: Manufactured by Osaka Soda Co., Ltd., product name: DAISO DAP 100 monomer, having a chemical structure represented by the following formula (3).

[0173]

[0174] (Flame retardant)

[0175] • Organic flame retardant 1: Aromatic condensed phosphate ester, "PX-200", manufactured by Daihachi Chemical Industry Co., Ltd.

[0176] • Organic flame retardant 2: Melamine polyphosphate, "MPP-A", manufactured by Sanwa Chemical Co., Ltd.

[0177] • Organic flame retardant 3: Phenyl silicone resin, "RSN-6018", manufactured by Dow Toray Co., Ltd.

[0178] • Organic flame retardant 4: Methyl silicone resin, "SILRES (registered trademark) MK", manufactured by Asahi Kasei Wacker Silicone Co., Ltd.

[0179] Inorganic flame retardant 5: Aluminum hydroxide, C-308, manufactured by Sumitomo Chemical Co., Ltd., with an average particle size d. 50 =8μm

[0180] Inorganic flame retardant 6: Aluminum hydroxide, C-31, manufactured by Sumitomo Chemical Co., Ltd., average particle size d 50 =50μm

[0181] • Organic / inorganic combined flame retardant 7: A mixture of ethylene bis(tetrabromophthalimide) and antimony trioxide

[0182] (Inorganic filler material)

[0183] Inorganic filler material 1: Glass fiber, "CS3E479", manufactured by Nitto Boseki Co., Ltd.

[0184] Inorganic filler material 2: Clay, “SP33”, manufactured by BASF South East Asia Pte Ltd.

[0185] Inorganic filler material 3: Calcium carbonate, TANCAL NS#100, manufactured by Nitto FUNKAKOGYO KK Co., Ltd.

[0186] (additive)

[0187] • Additive 1 (Mold Release Agent): Calcium stearate, "Ca-St", manufactured by Nitto Chemical Industry Co., Ltd.

[0188] Additive 2 (pigment): Carbon black, "Carbon Black #750", manufactured by Mitsubishi Chemical Corporation.

[0189] (2) Preparation of flame-retardant resin composition

[0190] <Examples 1-11, Comparative Examples 1-2>

[0191] The components were mixed according to the proportions (parts by mass) and number of roller rotations (times) shown in Table 1 to prepare a flame-retardant resin composition.

[0192] (3) Measurement of color difference

[0193] (i) Using the obtained flame-retardant resin compositions, test panels (120 mm square, 2 mm thick) were made at a mold temperature of 175 °C and a curing time of 3 minutes.

[0194] (ii) With the center of one side of the vertically placed test plate aligned with the torch burner (Shinfuji Burner Co., Ltd. "Power Torch RZ-720E", 2.2kW) at an angle of 90° relative to the test plate (approximately 30mm relative to the flame length of about 100mm), make it contact the flame for 5 minutes.

[0195] (iii) For the center of the other side of the test plate and two points 3 mm away from the center on a straight line passing through the center of the other side, measure the color difference before and after contact with the flame, and calculate the average value (ΔEr).

[0196] (iv) Additionally, for the center of one face of the test plate obtained in step (ii), and two points 3 mm away from the center on a straight line passing through the center of the one face, the color difference before and after contact with the flame is measured, and the average value (ΔEf) is calculated.

[0197] The color difference was measured using "CR-241" manufactured by Konica Minolta, Inc.

[0198] (4) UL-94 standard

[0199] Test panels (125mm × 13mm, 0.75mm thick) were prepared using a flame-retardant resin composition at a mold temperature of 175°C and a curing time of 3 minutes, and tested according to UL-94 standards. The results are shown in Table 1.

[0200] (5) Evaluation

[0201] Using a flame-retardant resin composition, a test plate (120mm square, 2mm thick) was prepared at a mold temperature of 175°C and a curing time of 3 minutes. The center of one side (surface) of the vertically placed test plate was aligned with a torch burner (Shinfuji Burner Co., Ltd. "Power Torch RZ-720E", 2.2kW) at an angle of 90° relative to the test plate (approximately 30mm relative to the flame length of 100mm) and exposed to the flame for 5 minutes.

[0202] For the test panels after exposure to flame, the ash area was calculated, and the "flame retardancy" was evaluated according to the following criteria. Specifically, the ash-white areas were evaluated as ash by visually observing the surface and back of the test panels. The results are shown in Table 1. Furthermore, as representative examples of the flame retardancy evaluation results of the test panels, photographs of the surface and back of the test panels of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 are shown in Table 1. Figures 1-4 In the middle. Additionally, in Figures 1-4 In the photo, some areas unrelated to the flame retardancy evaluation have been masked.

[0203] ○: No graying.

[0204] △: Ashing is present. The ashing area is less than 20cm². 2

[0205] ×: Ashing is present. The ash-covered area is 20cm². 2 above

[0206] [Table 1]

[0207]

[0208] This application claims priority based on Japanese Patent Application No. 2024-007884, filed on January 23, 2024, the entire contents of which are incorporated herein by reference.

Claims

1. A flame-retardant resin composition comprising a thermosetting resin and a flame retardant, wherein the flame-retardant resin composition is characterized in that: The following steps yield ΔEr below 30. step: (i) Using the flame-retardant resin composition, a test plate with a size of 120 mm square and a thickness of 2 mm was prepared under the conditions of a mold temperature of 175°C and a curing time of 3 minutes; (ii) With the flame in contact with the burner at the center of one face of the vertically placed test plate at an angle of 90° relative to the test plate, the burner is brought into contact with the flame for 5 minutes, wherein, The flame length of the flare burner is approximately 100 mm, and the distance between the flare burner and the test plate is 30 mm; and (iii) For the center of the other side of the test plate and two points 3 mm away from the center on a straight line passing through the center of the other side, measure the color difference before and after contact with the flame, and calculate the average value ΔEr.

2. The flame-retardant resin composition according to claim 1, characterized in that: The flame retardant comprises one or more selected from organic and inorganic flame retardants.

3. The flame-retardant resin composition according to claim 1 or 2, characterized in that: It also contains inorganic filler materials.

4. The flame-retardant resin composition according to any one of claims 1 to 3, characterized in that: For the center of one side of the test plate obtained in step (ii), and two points 3 mm away from the center on a straight line passing through the center of the one side, the color difference before and after contact with the flame is measured, and the average value ΔEf is calculated to be 0 to 100.

5. The flame-retardant resin composition according to any one of claims 1 to 4, characterized in that: The content of the flame retardant is 1 to 45 parts by weight relative to 100 parts by weight of the flame retardant resin composition.

6. The flame-retardant resin composition according to any one of claims 1 to 5, characterized in that: The thermosetting resin comprises one or more selected from phenolic resin, diallyl phthalate resin, unsaturated polyester resin, epoxy resin, melamine resin and furan resin.

7. The flame-retardant resin composition according to claim 3, characterized in that: The inorganic filler material is selected from one or more of the following: fiber fillers, plate fillers, and spherical fillers.

8. The flame-retardant resin composition according to claim 3 or 7, characterized in that: The inorganic filler material is selected from one or more of glass fiber, carbon fiber, metal fiber and mineral filler.

9. The flame-retardant resin composition according to claim 3, 7, or 8, characterized in that: The content of the inorganic filler material is 30 to 85 parts by weight relative to 100 parts by weight of the flame-retardant resin composition.

10. The flame-retardant resin composition according to any one of claims 1 to 9, characterized in that: Using this flame-retardant resin composition, a test plate with dimensions of 125mm × 13mm and a thickness of 0.75mm was prepared under the conditions of a mold temperature of 175°C and a curing time of 3 minutes. In the test according to the UL-94 standard, it met the V-1 standard of UL-94.

11. The flame-retardant resin composition according to any one of claims 1 to 10, characterized in that: The flame-retardant resin composition can be used in automotive components.

12. A cured product, characterized in that: The cured product of the flame-retardant resin composition according to any one of claims 1 to 10.

13. A vehicle-mounted component, characterized in that: Cured products comprising the flame-retardant resin composition of claim 11.

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