Flame retardant composition

Abstract

The invention provides a flame-retardant composition, which comprises (A) a compound with the structure of the following formula (I): [formula (I)] # imgabs0 # (B) maleimide compound; and (C) an allyl-containing compound which does not have a structure of formula (I) wherein the flame retardant composition has a phosphorus content of 0.5 wt% to 1.4 wt% based on the total weight of the solvent-free flame retardant composition.

Description

Technical Field

[0001] The present invention relates to a flame retardant composition, in particular to a flame retardant composition comprising a phosphorus-containing compound with a specific structure. The present invention also relates to a prepreg and a metal foil laminate using the flame retardant composition. Background Art

[0002] Electronic materials used for printed circuit boards must have a certain degree of flame retardancy to comply with relevant regulations. Generally speaking, phosphorus can be added to electronic materials to improve the overall flame retardancy. The phosphorus can be added by adding phosphorus-containing compounds, and common phosphorus-containing compounds include 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, DOPO). However, although the addition of DOPO can improve the flame retardancy of electronic materials, it cannot increase the molecular weight of the resin and extend the molecular chain of the resin, which will adversely affect other properties of the resin, such as electrical properties, heat resistance, etc.

[0003] Other existing phosphorus-containing compounds include dihydroxy DOPO compounds, such as 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthren e-10-oxide and dihydroxyphenyl (diphenyl) phosphine oxide. The phosphorus-containing compounds can improve the problem of being unable to extend the molecular chain, but the hydroxyl groups they possess make it impossible to combine with other high-performance resins (such as bismaleimide resins), resulting in the electronic materials used still failing to meet expectations in terms of heat resistance and dimensional stability. Summary of the invention

[0004] In view of the above technical problems, the present invention provides a flame retardant composition, which comprises a phosphorus-containing compound with a specific structure, a maleimide compound, and an allyl-containing compound without the above specific structure. By combining the above components, the flame retardant composition of the present invention can provide an electronic material with excellent flame retardancy, excellent heat resistance and good dimensional stability.

[0005] Therefore, an object of the present invention is to provide a flame retardant composition comprising the following components:

[0006] (A) a compound having the following formula (I),

[0007] [Formula (I)]

[0008]

[0009] (B) a maleimide compound; and

[0010] (C) an allyl group-containing compound which does not have the structure of formula (I),

[0011] The phosphorus content of the flame retardant composition is 0.5 wt % to 1.4 wt % based on the total weight of the flame retardant composition without solvent.

[0012] In one embodiment of the present invention, the content of the compound (A) having the structure of formula (I) is 8 wt % to 20 wt % based on the total weight of the flame retardant composition without solvent.

[0013] In one embodiment of the present invention, the content of the maleimide compound (B) is 20 wt % to 55 wt % based on the total weight of the flame retardant composition without solvent.

[0014] In one embodiment of the present invention, the content of the allyl group-containing compound (C) is 20 wt % to 55 wt % based on the total weight of the flame retardant composition without solvent.

[0015] In one embodiment of the present invention, the maleimide compound (B) is a multifunctional maleimide compound. In a preferred embodiment of the present invention, the maleimide compound (B) is a bismaleimide compound.

[0016] In one embodiment of the present invention, the maleimide compound (B) is selected from the following group:

[0017] and combinations thereof, wherein n is an integer from 1 to 10.

[0018] In one embodiment of the present invention, the maleimide compound (B) is selected from the following group: 1,2-bismaleimidoethane, 1,6-bismaleimidohexane, 1,3-bismaleimidobenzene, 1,4-bismaleimidobenzene, 2,4-bismaleimidotoluene, 4,4'-bismaleimidodiphenylmethane, 4,4'-bismaleimidodiphenyl ether, 3,3'-bismaleimidodiphenyl sulfone, 4,4'-bismaleimidodiphenyl sulfone, 4,4'-bismaleimidodicyclohexylmethane, 3,5-bis(4-maleimidophenyl)pyridine, 2,6-bismaleimidopyridine, 1,3-bis(maleimidomethyl)cyclohexane, 1,3-bis(maleimidomethyl)benzene, 1,1-bis(4-maleimidophenyl)cyclohexane, 1,3-bis(dichloromaleimido)benzene, 4,4'-biscitraconimidodiphenylmethane henylmethane), 2,2-bis(4-maleimidophenyl)propane, 1-phenyl-1,1-bis(4-maleimidophenyl)ethane, α,α-bis(4-maleimidophenyl)toluene, 3,5-bismaleimido-1,2,4-triazole, N,N'-ethylene bismaleimide, N,N'-hexamethylene bismaleimide, N,N'-m-phenylene bismaleimide, N,N'-p-phenylene bismaleimide, N,N '-4,4'-diphenylmethane bismaleimide, N,N'-4,4'-diphenyl ether bismaleimide, N,N'-4,4'-diphenyl sulfone bismaleimide, N,N'-4,4'-dicyclohexylmethane bismaleimide, N,N'-α,α'-4,4'-dimethylenecyclohexane bismaleimide, N,N'-m-xylene bismaleimide, N,N'-4,4'-diphenylcyclohexane bismaleimide, phenylmethane maleimide oligomers, and combinations thereof.

[0019] In one embodiment of the present invention, the allyl-containing compound (C) is a multifunctional allyl-containing compound. In a preferred embodiment of the present invention, the allyl-containing compound (C) is selected from the following group: diallyl bisphenol A, diallyl bisphenol F, diallyl bisphenol S, and combinations thereof.

[0020] In one embodiment of the present invention, the flame retardant composition further comprises a prepolymer of the compound (A) having the structure of formula (I), the maleimide compound (B) and the allyl group-containing compound (C).

[0021] In one embodiment of the present invention, the prepolymer has the following structure of formula (II) or formula (III):

[0022] [Formula (II)]

[0023]

[0024] [Formula (III)]

[0025]

[0026] Where R B is a structural unit derived from the maleimide compound (B), and R C is a structural unit derived from the allyl group-containing compound (C).

[0027] In one embodiment of the present invention, the flame retardant composition further comprises a thermosetting resin selected from the following group: epoxy resin, thermosetting phenolic resin, thermosetting benzoxazine resin, thermosetting polyphenylene ether resin, and combinations thereof.

[0028] In one embodiment of the present invention, the flame retardant composition further comprises an additive selected from the following group: a hardening accelerator, a catalyst, an elastomer, a filler, a toughening agent, and a combination thereof.

[0029] Another object of the present invention is to provide a prepreg, which is prepared by impregnating or coating a substrate with the flame retardant composition described above, and drying the impregnated or coated substrate.

[0030] Another object of the present invention is to provide a metal foil laminate produced by laminating the above-mentioned prepreg and metal foil, or by coating the above-mentioned flame retardant composition on metal foil and drying the coated metal foil.

[0031] In order to make the above-mentioned objectives, technical features and advantages of the present invention more obvious and easy to understand, some specific implementation schemes are described in detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the infrared spectrum of the flame retardant composition of Example 1 measured by Fourier-transform infrared spectroscopy (FTIR).

[0033] Figure 2 This is the infrared spectrum of the flame retardant composition of Example 2 measured by FTIR. DETAILED DESCRIPTION

[0034] Some specific embodiments according to the present invention will be described in detail below; however, the present invention can also be practiced in a variety of different forms, and the protection scope of the present invention should not be limited to the specific embodiments.

[0035] Unless otherwise stated, the terms “a”, “an”, “the” and similar terms used in the specification and claims should be understood to include both the singular and the plural.

[0036] Unless otherwise specified, in this specification and claims, the term "room temperature" refers to a temperature of 25°C.

[0037] Unless otherwise stated, when describing the contents of components contained in a solution, mixture, composition, or glue in this specification and claims, the weight of the solvent is not included in the calculation.

[0038] The present invention provides an electronic material having excellent flame retardancy, excellent heat resistance and good dimensional stability by combining a phosphorus-containing compound, a maleimide compound and an allyl-containing compound with a specific structure, and the electronic material is particularly suitable as a dielectric material for a printed circuit board. The flame retardant composition of the present invention and its application are described in detail below.

[0039] 1. Flame retardant composition

[0040] The flame retardant composition of the present invention comprises a compound (A) having a structure of the following formula (I), a maleimide compound (B) and an allyl group-containing compound (C), wherein the allyl group-containing compound (C) does not have a structure of the following formula (I).

[0041] [Formula (I)]

[0042]

[0043] In the flame retardant composition of the present invention, the phosphorus content of the flame retardant composition is 0.5% by weight to 1.4% by weight, such as 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, or 1.4%, based on the total weight of the flame retardant composition without solvent, or a range consisting of any two of the above values. When the phosphorus content is lower than the specified range, the electronic material produced cannot have satisfactory flame retardancy and heat resistance. When the phosphorus content is higher than the specified range, the electronic material produced may have good flame retardancy and heat resistance, but the mechanical properties and dielectric properties are deteriorated.

[0044] 1.1. Compound (A) having the structure of formula (I)

[0045] In the flame retardant composition of the present invention, compound (A) is a compound with a specific structure, and the specific structure is shown in the following formula (I):

[0046]

[0047] Different from DOPO or bisphenol-type DOPO compounds, compound (A) having the structure of formula (I) has an allyl group as a reactive functional group on the basis of having a DOPO structure, thereby being able to react with other unsaturated resins (such as bismaleimide resin) and extend the resin molecular chain, thereby further improving the flame retardant effect.

[0048] In the flame retardant composition of the present invention, the content of the compound (A) having the structure of formula (I) may be 8% by weight to 20% by weight, for example, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20% by weight, or a range between any two of the above values, based on the total weight of the flame retardant composition without solvent. When the content of the compound (A) having the structure of formula (I) is lower than the specified range, the electronic material obtained may not have satisfactory flame retardancy and heat resistance. When the content of the compound (A) having the structure of formula (I) is higher than the specified range, the mechanical properties and dielectric properties of the electronic material obtained may deteriorate.

[0049] The compound (A) having the structure of formula (I) can be prepared by the following method. First, DOPO is reacted with at least two hydroxyphenyl-containing compounds in the presence of p-toluenesulfonic acid to obtain a bisphenol-type DOPO-based compound. Next, the bisphenol-type DOPO-based compound is reacted with an allyl-containing compound to obtain a diallyl ether compound containing a DOPO group. Thereafter, the diallyl ether compound containing a DOPO group is subjected to functional group rearrangement at high temperature to obtain a compound (A) having the structure of formula (I).

[0050] Examples of the aforementioned hydroxyphenyl-containing compounds include, but are not limited to, phenol, hydroquinone, resorcinol, catechol, 4'-hydroxyacetophenone, 3'-hydroxyacetophenone, 2'-hydroxyacetophenone, p-hydroxybenzoic acid, m-hydroxybenzoic acid, and o-hydroxybenzoic acid. The aforementioned hydroxyphenyl-containing compounds may be used alone or in combination. Examples of the aforementioned allyl-containing compounds include, but are not limited to, allyl chloride, allyl bromide, allyl iodide, allyl alcohol, and allylamine. The aforementioned allyl-containing compounds may be used alone or in combination.

[0051] 1.2. Maleimide compound (B)

[0052] In the flame retardant composition of the present invention, the maleimide compound (B) is a compound having a maleimide structure. The maleimide structure has a reactive carbon-carbon double bond, so the maleimide compound (B) can react with other components having unsaturated groups. Examples of the unsaturated groups include, but are not limited to, vinyl, vinyl benzyl, allyl, acrylic, and methacrylic.

[0053] The maleimide compound (B) is preferably a polyfunctional maleimide compound, such as a bismaleimide compound, a trimaleimide compound, or a tetramaleimide compound, and more preferably a bismaleimide compound.

[0054] In one embodiment of the present invention, the maleimide compound (B) is selected from the following group:

[0055] and combinations thereof, wherein n is an integer from 1 to 10.

[0056] In one embodiment of the present invention, the maleimide compound (B) is selected from the following group: 1,2-bismaleimidoethane, 1,6-bismaleimidohexane, 1,3-bismaleimidobenzene, 1,4-bismaleimidobenzene, 2,4-bismaleimidotoluene, 4,4'-bismaleimidodiphenylmethane, 4,4'-bismaleimidodiphenyl ether, 3,3'-bismaleimidodiphenyl sulfone, 4,4'-bismaleimidodiphenyl sulfone, 4,4'-bismaleimidodicyclohexylmethane, 3,5-bis(4-maleimidophenyl)pyridine, 2,6-bismaleimidopyridine, 1,3-bis(maleimidomethyl)cyclohexane, 1,3-bis(maleimidomethyl)benzene, 1,1-bis(4-maleimidophenyl)cyclohexane, 1,3-bis(dichloromaleimido)benzene, 4,4'-biscitraconimidodiphenylmethane iphenylmethane), 2,2-bis(4-maleimidophenyl)propane, 1-phenyl-1,1-bis(4-maleimidophenyl)ethane, α,α-bis(4-maleimidophenyl)toluene, 3,5-bismaleimido-1,2,4-triazole, N,N'-ethylenebismaleimide, N,N'-hexamethylenebismaleimide, N,N'-m-phenylenebismaleimide, N,N'-p-phenylenebismaleimide, N,N'-4,4'-diphenylmethane bismaleimide, N,N'-4,4'-diphenyl ether bismaleimide, N,N'-4,4'-diphenyl sulfone bismaleimide, N,N'-4,4'-dicyclohexylmethane bismaleimide, N,N'-α,α'-4,4'-dimethylenecyclohexane bismaleimide, N,N'-m-xylene bismaleimide, N,N'-4,4'-diphenylcyclohexane bismaleimide, and phenylmethane maleimide oligomer. The aforementioned maleimide compounds may be used alone or in combination of two or more.

[0057] In the flame retardant composition of the present invention, the content of the maleimide compound (B) may be 20% by weight to 55% by weight, based on the total weight of the flame retardant composition without a solvent, for example, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, or 55% by weight, or in a range consisting of any two of the above values.

[0058] 1.3. Allyl compounds (C)

[0059] Herein, the allyl-containing compound (C) refers to a compound containing an allyl group and not having the structure of the aforementioned formula (I). The allyl-containing compound (C) is preferably a multifunctional allyl-containing compound, in particular a diallyl compound. Examples of the diallyl compound include, but are not limited to, diallyl bisphenol A, diallyl bisphenol F, and diallyl bisphenol S, and each of the diallyl compounds can be used alone or in combination.

[0060] In the flame retardant composition of the present invention, the content of the allyl compound (C) may be 20% by weight to 55% by weight, based on the total weight of the flame retardant composition without a solvent, for example, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, or 55% by weight, or in the range consisting of any two of the above values.

[0061] 1.4. Other ingredients and prepolymers

[0062] The flame retardant composition of the present invention may further comprise other thermosetting components in addition to the maleimide compound (B) to adaptively improve the physical and chemical properties or electrical properties of the electronic material. Examples of the thermosetting components include, but are not limited to, thermosetting resins selected from the following groups: epoxy resins, thermosetting phenolic resins, thermosetting benzoxazine resins, and thermosetting polyphenylene ether resins. The aforementioned thermosetting resins may be used alone or in combination.

[0063] The flame retardant composition of the present invention may further include other conventional additives to adaptively improve the physicochemical properties or electrical properties of the electronic material produced, or to improve the processability of the flame retardant composition. Examples of the additives include, but are not limited to, hardeners, catalysts, elastomers, fillers, dispersants, toughening agents, viscosity modifiers, coupling agents, etc. The aforementioned additives may be used alone or in combination. The selection of the additives is selected by a person skilled in the art of the present invention according to actual needs after reading the specification of the present case, and is not the technical focus of the present invention, so it will not be described in detail here.

[0064] In addition, the components of the flame retardant composition of the present invention may be present in the composition in the form of monomers or in the form of prepolymers. Therefore, the flame retardant composition may further comprise one or more prepolymers. Examples of the prepolymers include a prepolymer of a compound (A) having a structure of formula (I) and a maleimide compound (B), a prepolymer of a maleimide compound (B) and an allyl-containing compound (C), and a prepolymer of a compound (A) having a structure of formula (I), a maleimide compound (B) and an allyl-containing compound.

[0065] In one embodiment of the present invention, the flame retardant composition further comprises a prepolymer having a structure of the following formula (II) or formula (III):

[0066] [Formula (II)]

[0067]

[0068] [Formula (III)]

[0069]

[0070] In formula (II) and formula (III), R B is a structural unit derived from the maleimide compound (B), and R C It is a structural unit derived from the allyl group-containing compound (C).

[0071] 1.5. Properties of flame retardant compositions

[0072] The flame retardant composition of the present invention can be analyzed by FTIR to identify the functional groups contained in the flame retardant composition. In one embodiment of the present invention, the flame retardant composition has an infrared spectrum at 751 cm -1 Up to 760cm -1 The PO-Ph absorption peak at 1705 cm -1 Up to 1715cm -1 The C=O absorption peak at 1637 cm -1 Up to 1639cm -1 C=C absorption peak.

[0073] In addition, the cured product obtained after the flame retardant composition of the present invention is cured has excellent flame resistance and heat resistance. In one embodiment of the present invention, the glass transition temperature (glass transition temperature, Tg) of the cured product of the flame retardant composition can reach 180°C to 220°C, for example, 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, or 220°C, or a range between any two of the above values. The 5% weight loss temperature (weight loss temperature, Tg) of the cured product of the flame retardant composition d 5) can reach 360°C to 385°C, such as 360°C, 365°C, 370°C, 375°C, 380°C, or 385°C, or a range between any two of the above values. The carbon residue at 800°C of the cured product of the flame retardant composition can reach 42% to 48% by weight, such as 42%, 43%, 44%, 45%, 46%, 47%, or 48% by weight, or a range between any two of the above values.

[0074] In addition, the cured product obtained after curing the flame retardant composition of the present invention also has excellent dimensional stability. In one embodiment of the present invention, the total expansion rate of the cured product of the flame retardant composition at 50°C to 260°C is only 1.8% to 2.3%, for example, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, or 2.3%, or a range consisting of any two of the above values.

[0075] 1.6. Preparation of flame retardant compositions

[0076] Regarding the preparation of the flame retardant composition, the components of the flame retardant composition, including the compound (A) having the structure of formula (I), the maleimide compound (B), the allyl group-containing compound (C), and other components (such as thermosetting resins or additives) as required, can be uniformly mixed with a stirrer and dissolved or dispersed in a solvent to form a slurry, a colloidal group, a varnish, etc. for subsequent processing. The solvent can be any inert solvent that can dissolve or disperse the components of the flame retardant composition but does not react with these components. For example, the solvents that can be used to dissolve or disperse the components of the flame retardant composition include but are not limited to: toluene, γ-butyrolactone, methyl ethyl ketone, cyclohexanone, butanone, acetone, xylene, methyl isobutyl ketone, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), propylene glycol methyl ether, dimethyl sulfoxide, and N-methyl-pyrolidone (NMP). The aforementioned solvents can be used alone or in combination. There is no particular limitation on the amount of the solvent used. In principle, it can be used as long as the components of the flame retardant composition can be uniformly dissolved or dispersed therein.

[0077] In addition, the reactive components in the flame retardant composition can be polymerized to form a prepolymer by heating to form a flame retardant composition containing a prepolymer. For example, a maleimide compound (B) and an allyl compound (C) can be mixed to obtain a mixture. Then, the mixture is heated to 120°C to 180°C, or the mixture is heated to 80°C to 180°C in the presence of a catalyst, and then a compound (A) having a structure of formula (I) is added and stirred for 10 minutes to 1 hour to react to form a prepolymer. Thereafter, a solvent is added to obtain a flame retardant composition containing a prepolymer.

[0078] 2. Prepreg and metal foil laminate

[0079] The present invention also provides a semi-cured sheet made from the above-mentioned flame retardant composition, wherein the semi-cured sheet is made by impregnating a substrate with the above-mentioned flame retardant composition or coating the above-mentioned flame retardant composition on a substrate, and drying the impregnated or coated substrate. The substrate may be a reinforcing material. Generally speaking, the material of the reinforcing material includes but is not limited to fibers selected from the following groups: glass fibers, inorganic fibers other than glass fibers, organic fibers, and combinations thereof. Examples of glass fibers include but are not limited to E-glass fibers (E-glass), NE-glass fibers (NE-glass), S-glass fibers (S-glass), L-glass fibers (L-glass), D-glass fibers (D-glass), T-glass fibers (T-glass), Q-glass fibers (Q-glass), UN-glass fibers (UN-glass), and spherical glass. Examples of inorganic fibers other than glass fibers include but are not limited to quartz fibers, paper fibers, and carbon fibers. Examples of organic fibers include, but are not limited to, polyimide, polyamide (e.g., Kevlar), polyester, liquid crystal polymer (e.g., liquid crystal polyester), polytetrafluoroethylene, ultra-high molecular weight polyethylene (UHMWPE), and high-modulus polypropylene (HMPP). The form of the reinforcement material includes, but is not limited to, woven fabric, non-woven fabric, roving, chopped strand mat, and surface mat.

[0080] In addition, the present invention also provides a metal foil laminated board made from the above-mentioned prepreg, which comprises a dielectric layer and a metal layer, wherein the dielectric layer is provided by the above-mentioned prepreg. Wherein, a plurality of layers of the above-mentioned prepreg can be stacked, and a metal foil (such as copper foil) is stacked on at least one outer surface of the dielectric layer formed by stacking the prepreg to provide a stack, and the stack is subjected to a hot pressing operation to obtain a metal foil laminated board. Alternatively, the flame retardant composition of the present invention can be directly coated on a metal foil and the coated metal foil can be dried to obtain a metal foil laminated board.

[0081] The outer metal foil of the metal foil laminate may be further patterned to produce a printed circuit board.

[0082] 3. Example

[0083] 3.1. Description of measurement method

[0084] The present invention is further illustrated by the following specific embodiments, wherein the measuring instruments and methods used are as follows:

[0085] [FTIR measurement]

[0086] First, 1 mg of the flame retardant composition was coated on a KBr ingot with a diameter of 13 mm and a thickness of 1 mm by a thin film method. Then, the KBr ingot coated with the flame retardant composition was placed in a Fourier transform infrared spectrometer (model: Spotlight 200i, purchased from PerkinElmer) and measured at 400 cm -1 Up to 4000cm -1 The measurement conditions are as follows: the infrared spectrum is measured by the transmission method with a resolution of 1 cm -1 , the cumulative number of times is 16 times.

[0087] [5% weight loss temperature (T d 5) Measurement]

[0088] First, the flame retardant composition was cured under the following curing conditions to obtain a cured product of the flame retardant composition: the temperature was raised from room temperature to 180°C and maintained for 1 hour, the temperature was raised to 200°C and maintained for 2 hours, the temperature was raised to 250°C and maintained for 6 hours, and then the temperature was naturally lowered to room temperature. Next, 5 mg to 10 mg of the cured product was taken as a sample and placed on a platinum plate, and the T of the sample was measured using a thermogravimetric analyzer (TGA, model: TGA-Q500, purchased from TA Instruments) according to IPC-TM-650-2.3.40. d 5. The measurement conditions are as follows: the sample is equilibrated at 50°C, then the temperature is raised to 800°C at a heating rate of 10°C / min, and T is calculated using the software attached to TGA. d 5.

[0089] [800℃ Carbon Residue Measurement]

[0090] First, the flame retardant composition is cured under the following curing conditions to obtain a cured product of the flame retardant composition: heating from room temperature to 180°C and maintaining for 1 hour, heating to 200°C and maintaining for 2 hours, and then heating to 250°C and maintaining for 6 hours, and then naturally cooling to room temperature. Next, 5 mg to 10 mg of the cured product is taken as a sample and placed on a platinum plate, and the 800°C residual carbon content of the sample is measured using a thermogravimetric analyzer TGA-Q500 and in accordance with IPC-TM-650-2.3.40. The measurement conditions are as follows: the sample is balanced at 50°C, and then the temperature is increased from 50°C to 800°C at a heating rate of 10°C / min, and the 800°C residual carbon content is calculated using the software attached to the TGA.

[0091] [Glass transition temperature (Tg) measurement]

[0092] First, the flame retardant composition is cured under the following curing conditions to obtain a cured product of the flame retardant composition: heating from room temperature to 180°C and maintaining for 1 hour, heating to 200°C and maintaining for 2 hours, and then heating to 250°C and maintaining for 6 hours, and then naturally cooling to room temperature. Next, the cured product is cut into test pieces with a volume of 3 cubic centimeters to 7 cubic centimeters, and the Tg of the test piece is measured using a thermomechanical analyzer (TMA, model: TMA-7, purchased from PerkinElmer) according to IPC-TM-650-2.4.24. The measurement conditions are as follows: the test piece is balanced at 50°C, then the temperature is increased from 50°C to 330°C at a heating rate of 10°C / min, the temperature is decreased from 330°C to 50°C at a cooling rate of 10°C / min, and the temperature is increased from 50°C to 330°C again at a heating rate of 10°C / min, and Tg is calculated using the software attached to TMA.

[0093] [Expansion rate measurement]

[0094] First, the flame retardant composition is cured under the following curing conditions to obtain a cured product of the flame retardant composition: heating from room temperature to 180°C and maintaining for 1 hour, heating to 200°C and maintaining for 2 hours, and then heating to 250°C and maintaining for 6 hours, and then naturally cooling to room temperature. Next, the cured product is cut into test pieces with a volume of 3 cubic centimeters to 7 cubic centimeters, and the total expansion rate of the test piece from 50°C to 260°C is measured using a thermal mechanical analyzer TMA-7 according to IPC-TM-650-2.4.24. The measurement conditions are as follows: the test piece is balanced at 50°C, then the temperature is increased from 50°C to 330°C at a heating rate of 10°C / min, the temperature is decreased from 330°C to 50°C at a cooling rate of 10°C / min, and the temperature is increased from 50°C to 330°C again at a heating rate of 10°C / min, and the total expansion rate from 50°C to 260°C is calculated using the software attached to TMA.

[0095] [Flammability test]

[0096] The flame retardancy level of each flame retardant and heat resistant composition is measured according to the UL 94 vertical burning test. In order to compare the flame retardancy effect of each flame retardant and heat resistant composition, glass fiber cloth 2116 is impregnated in Examples 1A to 6A and Comparative Examples 1A to 3A, respectively, and baked at 150°C for 7 minutes to prepare prepregs. Then, each prepreg is cut into 13*13 square centimeters test pieces, covered with copper foil on the top and bottom, and vacuum hot pressed at 220°C for 2 hours to prepare test pieces. Cut into 13*1.3 square centimeters with a shearing machine, peel off the outer copper foil, and finally perform a vertical burning test with reference to UL 94.

[0097] According to the UL 94 flame retardant test standard, the V0 grade result means that after two 10-second flame tests, the test piece stops burning within 10 seconds and no burning dripping occurs; the V1 grade means that after two 10-second flame tests, the test condition stops burning within 60 seconds and no burning dripping occurs. In this test example, five test pieces were taken from each group of samples and five UL 94 flame retardant tests were performed, and the flame retardant effect was re-tested with a new test piece each time.

[0098] Table 5 below lists the time (in seconds) that each test piece continued to burn after the first 10-second flame test and the removal of the flame, and the time (in seconds) that the test piece continued to burn after the second 10-second flame test and the removal of the flame in the UL 94 vertical burning test. As shown in Table 5 below, after the first test piece of Example 1A was subjected to the UL 94 vertical burning test, there was no continued burning after the first 10-second flame test and the removal of the flame, and there was no continued burning after the second 10-second flame test and the removal of the flame; on the contrary, after the first test piece of Comparative Example 1A was subjected to the UL 94 vertical burning test, the test piece continued to burn for 13.8 seconds after the first 10-second flame test and the removal of the flame, and the test piece continued to burn for 2.6 seconds after the second 10-second flame test and the removal of the flame.

[0099] 3.2. Preparation of compound (A) having the structure of formula (I)

[0100] First, 216.2 g (1 mol) of DOPO (CAS No.: 35948-25-5), 470.5 g (5 mol) of phenol (CAS No.: 108-95-2), 136.2 g (1 mol) of 4'-hydroxyacetophenone (CAS No.: 99-93-4) and 8.65 g (4 wt% based on the weight of DOPO) of p-toluenesulfonic acid (CAS No.: 104-15-4) were added to a 3000 ml three-necked reaction flask and stirred uniformly at room temperature in advance. Then, the three-necked reaction flask was heated to 130° C. and stirred at this temperature for 6 hours to obtain a mixture. After the temperature of the mixture was cooled to room temperature, an intermediate product was separated from the mixture. The intermediate product was washed with ethanol, filtered and dried to obtain a bisphenol-type DOPO-based compound A1 in the form of a white powder having the following structure. The yield of the bisphenol DOPO compound A1 was 85%, the melting point was 306° C. The elemental analysis results showed that carbon, hydrogen and oxygen accounted for 72.48%, 4.65% and 14.90% respectively.

[0101] Bisphenol DOPO compound A1

[0102] 245 g (0.572 mol) of bisphenol-type DOPO compound A1, 400 g of dimethyl sulfoxide (CAS No.: 67-68-5) and 96.1 g of 49% NaOH were added to a 1-liter three-necked reaction flask and mixed, and then heated to 60° C. under continuous stirring. Next, 93.9 g of allyl chloride was added to the three-necked reaction flask to react until the salts of the side reaction were completely precipitated. The crude product was subjected to oil-water extraction, and the oil phase product was taken out and concentrated to remove the solvent to obtain 240 g of a pale yellow DOPO group-containing diallyl ether compound A2, which has the following structure.

[0103] Diallyl ether compound A2

[0104] Then, 240 g of the DOPO-containing diallyl ether compound A2 was added to a 0.5-liter three-necked reaction flask, and the temperature was raised to 220° C., and stirred at the temperature for 2 hours to perform the transposition of the allyl group. After confirming that the transposition was completed using a Fourier transform infrared spectrometer, a compound (A) having a structure of formula (I) was obtained.

[0105] 3.3. Preparation of flame retardant compositions

[0106] [Example 1]

[0107] 13 grams of 4,4'-bismaleimidodiphenylmethane (CAS No.: 13676-54-5), 14 grams of phenylmethane maleimide oligomer (model: BES1-5950, purchased from Regina Chemical China) and 27 grams of 2,2'-diallylbisphenol A (CAS No.: 1745-89-7) were added to a beaker and heated to 150°C. Then, 6 grams of compound (A) having the structure of formula (I) prepared in Synthesis Example 1 was added to the beaker and stirred for 30 minutes. 40 grams of methyl ethyl ketone was added to the beaker and stirred evenly to obtain 100 grams of the flame retardant composition of Example 1. The phosphorus content of the flame retardant composition of Example 1 is 0.61% by weight.

[0108] [Example 2]

[0109] 12.5 g of 4,4'-bismaleimidodiphenylmethane, 13.5 g of phenylmethane maleimide oligomer BES1-5950 and 26.5 g of 2,2'-diallylbisphenol A were added to a beaker and heated to 150°C. Then, 7.5 g of compound (A) having the structure of formula (I) prepared in Synthesis Example 1 was added to the beaker and stirred for 30 minutes. 40 g of methyl ethyl ketone was added to the beaker and stirred evenly to obtain 100 g of the flame retardant composition of Example 2. The phosphorus content of the flame retardant composition of Example 2 is 0.76% by weight.

[0110] [Example 3]

[0111] 12 grams of 4,4'-bismaleimidodiphenylmethane, 13 grams of phenylmethane maleimide oligomer BES1-5950 and 26 grams of 2,2'-diallylbisphenol A were added to a beaker and heated to 150°C. Then, 9 grams of compound (A) having the structure of formula (I) prepared in Synthesis Example 1 was added to the beaker and stirred for 30 minutes. 40 grams of methyl ethyl ketone was added to the beaker and stirred evenly to obtain 100 grams of the flame retardant composition of Example 3. The phosphorus content of the flame retardant composition of Example 3 was 0.91% by weight.

[0112] [Comparative Example 1]

[0113] 13 g of 4,4'-bismaleimidodiphenylmethane, 14 g of phenylmethane maleimide oligomer BES1-5950 and 27 g of 2,2'-diallylbisphenol A were added to a beaker, heated to 150°C and stirred for 30 minutes. 46 g of methyl ethyl ketone was added to the beaker and stirred evenly to obtain 100 g of the flame retardant composition of Comparative Example 1. The phosphorus content of the flame retardant composition of Comparative Example 1 was 0 wt%.

[0114] [Comparative Example 2]

[0115] 13 grams of 4,4'-bismaleimidodiphenylmethane, 14 grams of phenylmethane maleimide oligomer BES1-5950 and 27 grams of 2,2'-diallylbisphenol A were added to a beaker and heated to 150°C. Then, 6 grams of DOPO (CAS No.: 35948-25-5) was added to the beaker and stirred for 30 minutes. 40 grams of methyl ethyl ketone was added to the beaker and stirred evenly to obtain 100 grams of the flame retardant composition of Comparative Example 2. The phosphorus content of the flame retardant composition of Comparative Example 2 was 1.43% by weight.

[0116] [Comparative Example 3]

[0117] 13 grams of 4,4'-bismaleimide diphenylmethane, 14 grams of phenylmethane maleimide oligomer BES1-5950 and 27 grams of 2,2'-diallylbisphenol A were added to a beaker and heated to 150°C. Then, 6 grams of bisphenol-type DOPO compound A1 was added to the beaker and stirred for 30 minutes. 40 grams of methyl ethyl ketone was added to the beaker and stirred evenly to obtain 100 grams of the flame retardant composition of Comparative Example 3. The phosphorus content of the flame retardant composition of Comparative Example 3 was 0.72% by weight.

[0118] [Comparative Example 4]

[0119] 13 grams of 4,4'-bismaleimide diphenylmethane, 14 grams of phenylmethane maleimide oligomer BES1-5950 and 27 grams of 2,2'-diallyl bisphenol A were added to a beaker and heated to 150°C. Then, 6 grams of diallyl ether compound A2 were added to the beaker and stirred for 30 minutes. 40 grams of methyl ethyl ketone were added to the beaker and stirred evenly to obtain 100 grams of the flame retardant composition of Comparative Example 4. The phosphorus content of the flame retardant composition of Comparative Example 4 was 0.61% by weight.

[0120] [Comparative Example 5]

[0121] 14 grams of 4,4'-bismaleimidodiphenylmethane, 15 grams of phenylmethane maleimide oligomer BES1-5950 and 28 grams of 2,2'-diallylbisphenol A were added to a beaker and heated to 150°C. Then, 3 grams of compound (A) having the structure of formula (I) prepared in Synthesis Example 1 was added to the beaker and stirred for 30 minutes. 40 grams of methyl ethyl ketone was added to the beaker and stirred evenly to obtain 100 grams of the flame retardant composition of Comparative Example 5. The phosphorus content of the flame retardant composition of Comparative Example 5 was 0.31% by weight.

[0122] [Comparative Example 6]

[0123] 13.5 g of 4,4'-bismaleimidodiphenylmethane, 14.5 g of phenylmethane maleimide oligomer BES1-5950 and 27.5 g of 2,2'-diallylbisphenol A were added to a beaker and heated to 150°C. Then, 4.5 g of compound (A) having the structure of formula (I) prepared in Synthesis Example 1 was added to the beaker and stirred for 30 minutes. 40 g of methyl ethyl ketone was added to the beaker and stirred evenly to obtain 100 g of the flame retardant composition of Comparative Example 6. The phosphorus content of the flame retardant composition of Comparative Example 6 was 0.46% by weight.

[0124] 3.4. Characteristics of flame retardant compositions

[0125] The properties of the flame retardant compositions of Examples 1 to 3 and Comparative Examples 1 to 6 were tested according to the methods described above, including T d 5. Carbon residue at 800°C, Tg, total expansion ratio from 50°C to 260°C, and flame retardancy (expressed as UL94 V0), and the results are recorded in Table 1.

[0126] In addition, the infrared spectra of Examples 1 and 2 were measured according to the method described above, and the results are shown in Figure 1 and Figure 2 middle. Figure 1 is the infrared spectrum of the flame retardant composition of Example 1, Figure 2 is the infrared spectrum of the flame retardant composition of Example 2. Figure 1 and Figure 2 It can be seen that the flame retardant composition of the present invention has a -1 Up to 760cm -1 It has a PO-Ph absorption peak at 1705cm -1 Up to 1715cm -1 It has a C=O absorption peak and a -1 Up to 1639cm -1 It has a C=C absorption peak.

[0127] Table 1: Properties of the flame retardant compositions of Examples 1 to 3 and Comparative Examples 1 to 6

[0128]

[0129] Generally speaking, electronic materials used in printed circuit boards with high dimensional stability usually need to have the following properties: Tg between 180℃ and 220℃, Tg between 360℃ and 385℃. d 5. The carbon residue at 800°C is between 42% and 48% by weight, and the total expansion rate at 50°C to 260°C is between 1.8% and 2.3%. As shown in Table 1, the flame retardant composition of the present invention has excellent flame retardancy (UL94 V0), excellent heat resistance (Tg, T d 5. Carbon residue at 800°C) and good dimensional stability (total expansion rate from 50°C to 260°C). Therefore, the flame retardant composition of the present invention is particularly suitable for use in the preparation of printed circuit boards.

[0130] In contrast, as shown in Table 1, the flame retardant composition not belonging to the present invention cannot simultaneously possess excellent flame retardancy (UL94 V0) and excellent heat resistance (Tg, T d 5. 800°C residual carbon content) and good dimensional stability (total expansion rate from 50°C to 260°C). Specifically, as shown in Comparative Example 1, if the flame retardant composition does not use a phosphorus-containing compound, the flame retardancy, heat resistance and dimensional stability are all poor. As shown in Comparative Examples 2 to 4, if the flame retardant composition uses other phosphorus-containing compounds that do not have the structure of formula (I), it still cannot have both excellent heat resistance and dimensional stability. As shown in Comparative Examples 5 and 6, even if the flame retardant composition contains a compound (A) with the structure of formula (I), if the overall phosphorus content is less than 0.5% by weight, the flame retardancy is poor and it still cannot have both excellent heat resistance and dimensional stability.

[0131] The above embodiments are only used to illustrate the principle and efficacy of the present invention and to describe the technical features of the present invention, and are not intended to limit the scope of protection of the present invention. Any changes or arrangements that can be easily completed by a person familiar with the present technology without violating the technical principle of the present invention are within the scope of the present invention.

Claims

1. A flame retardant composition, characterized in that: Include: (A) a compound having the following formula (I), [Formula (I)] (B) a maleimide compound; as well as (C) an allyl group-containing compound which does not have the structure of formula (I), The phosphorus content of the flame retardant composition is 0.5 wt % to 1.4 wt % based on the total weight of the flame retardant composition without solvent.

2. The flame retardant composition according to claim 1, characterized in that: Based on the total weight of the flame retardant composition without solvent, the content of the compound (A) having the structure of formula (I) is 8 wt % to 20 wt %.

3. The flame retardant composition according to claim 1, characterized in that: The content of the maleimide compound (B) is 20 wt % to 55 wt % based on the total weight of the flame retardant composition excluding the solvent.

4. The flame retardant composition according to claim 1, characterized in that: The allyl group-containing compound (C) is contained in an amount of 20 to 55 wt % based on the total weight of the flame retardant composition excluding the solvent.

5. The flame retardant composition according to claim 1, characterized in that: The maleimide compound (B) is a polyfunctional maleimide compound.

6. The flame retardant composition according to claim 5, characterized in that: The maleimide compound (B) is selected from the following group: and combinations thereof, wherein n is an integer from 1 to 10.

7. The flame retardant composition according to claim 5, characterized in that: The maleimide compound (B) is selected from the following group: 1,2-bismaleimidoethane, 1,6-bismaleimidohexane, 1,3-bismaleimidobenzene, 1,4-bismaleimidobenzene, 2,4-bismaleimidotoluene, 4,4'-bismaleimidodiphenylmethane, 4,4'-bismaleimidodiphenyl ether, 3,3'-bismaleimidodiphenyl sulfone, 4,4'-bismaleimidodiphenyl sulfone, 4,4'-Bismaleimidodicyclohexylmethane, 3,5-bis(4-maleimidophenyl)pyridine, 2,6-bismaleimidopyridine, 1,3-bis(maleimidomethyl)cyclohexane, 1,3-bis(maleimidomethyl)benzene, 1,1-bis(4-maleimidophenyl)cyclohexane, 1,3-bis(dichloromaleimido)benzene, 4,4'-biscitraconamidodiphenylmethane, 2,2-bis(4-maleimidophenyl) 1-phenyl-1,1-bis(4-maleimidophenyl)propane, α,α-bis(4-maleimidophenyl)toluene, 3,5-bismaleimido-1,2,4-triazole, N,N'-ethylene bismaleimide, N,N'-hexamethylene bismaleimide, N,N'-m-phenylene bismaleimide, N,N'-p-phenylene bismaleimide, N,N'-4,4'-diphenylmethane bis(maleimidophenyl)propane, 1-phenyl-1,1-bis(4-maleimidophenyl)ethane ... Maleimide, N,N'-4,4'-diphenyl ether bismaleimide, N,N'-4,4'-diphenyl sulfone bismaleimide, N,N'-4,4'-dicyclohexylmethane bismaleimide, N,N'-α,α'-4,4'-dimethylenecyclohexane bismaleimide, N,N'-m-xylene bismaleimide, N,N'-4,4'-diphenylcyclohexane bismaleimide, phenylmethane maleimide oligomers, and combinations thereof.

8. The flame retardant composition according to any one of claims 1 to 7, characterized in that The allyl group-containing compound (C) is a multifunctional allyl group-containing compound.

9. The flame retardant composition according to claim 8, characterized in that: The allyl group-containing compound (C) is selected from the following group: diallyl bisphenol A, diallyl bisphenol F, diallyl bisphenol S, and combinations thereof.

10. The flame retardant composition according to any one of claims 1 to 7, characterized in that: The invention also comprises a prepolymer of the compound (A) having the structure of formula (I), the maleimide compound (B) and the allyl group-containing compound (C).

11. The flame retardant composition according to claim 10, characterized in that: The prepolymer has the following structure of formula (II) or formula (III): [Formula (II)] [Formula (III)] Where R B is a structural unit derived from the maleimide compound (B), and R C is a structural unit derived from the allyl group-containing compound (C).

12. The flame retardant composition according to any one of claims 1 to 7, characterized in that: The invention also comprises a thermosetting resin selected from the group consisting of epoxy resin, thermosetting phenolic resin, thermosetting benzoxazine resin, thermosetting polyphenylene ether resin, and combinations thereof.

13. The flame retardant composition according to any one of claims 1 to 7, characterized in that: The invention also comprises an additive selected from the group consisting of a hardening accelerator, a catalyst, an elastomer, a filler, a toughening agent, and a combination thereof.

14. A prepreg, characterized in that: The flame retardant composition is prepared by impregnating or coating a substrate with the flame retardant composition according to any one of claims 1 to 13, and drying the impregnated or coated substrate.

15. A metal foil laminate, characterized in that: The flame retardant composition is prepared by laminating the prepreg according to claim 14 with a metal foil, or by coating the flame retardant composition according to any one of claims 1 to 13 on a metal foil and drying the coated metal foil.

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