A high-heat-resistant, high-flame-retardant, low-dielectric benzoxazine resin and a preparation method thereof

Abstract

The application discloses a high-heat-resistance, high-flame-retardant and low-dielectric benzoxazine resin shown in formula (1) and a preparation method thereof, characterized by the following steps: adding a main chain type benzoxazine resin, DOPO and a solvent into a reactor provided with a stirrer, a thermometer and a condenser, and then heating to 80-100 DEG C for 30-100 min; and then adjusting the temperature to 100-120 DEG C for 30-100 min, so as to obtain the high-heat-resistance, high-flame-retardant and low-dielectric benzoxazine resin. The high-heat-resistance, high-flame-retardant and low-dielectric benzoxazine resin prepared by the application has the characteristics of halogen-free, high flame resistance, high heat resistance, good toughness and good dielectric property, and is especially suitable for being used as a raw material for high-frequency and high-speed copper-clad plates, and can also be used in the fields of laminated boards, integrated circuit packaging and high-density internet.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of organic compounds and preparation thereof, and relates to a high-heat-resistant, high-flame-retardant and low-dielectric benzoxazine resin and a preparation method thereof. The high-heat-resistant, high-flame-retardant and low-dielectric benzoxazine resin (prepared by the present application) is particularly suitable for use as a raw material for high-frequency high-speed copper-clad plates, and can also be used in the fields of laminated boards, integrated circuit packaging, high-density Internet, etc. BACKGROUND

[0002] With the rapid development of artificial intelligence, 5G communication, intelligent driving, etc., new requirements are constantly being put forward for PCB substrates and base material resins, which are important components of electronic products, and the substrates and resins are required to have higher heat resistance, better flame retardancy, and better dielectric properties. Conventional benzoxazine resins such as bisphenol A type and bisphenol F type resins have poor heat resistance, low flame retardancy, and slightly poor dielectric properties, and are only suitable for pressing of ordinary copper-clad plates and cannot be applied to high-frequency high-speed copper-clad plates. Therefore, people have tried to further develop high-heat-resistant, high-flame-retardant and low-dielectric benzoxazines.

[0003] In order to further improve the heat resistance of benzoxazine resin, in the prior art, CN102702128A discloses "ether bond-containing bisamine type fluorenyl benzoxazine", CN102702225A discloses "tetraphenol fluorenyl benzoxazine and its preparation method", CN108546272A discloses "Si-O-Ph organic-inorganic hybrid bond cross-linked polybenzoxazine, polybenzoxazine monomer and its preparation method", 102584884A discloses "benzoxazine monomer, benzoxazine precursor and low dielectric benzoxazine resin", which introduces fluorenyl, Si-O-Ph hybrid bond, siloxane group and the like into the structure of benzoxazine resin to improve the heat resistance; in order to improve the flame retardance of benzoxazine resin, CN103755741A discloses "a bisphenol A-monobenzoxazine containing DOPO and its preparation method", CN108033981A discloses "a phosphorus-containing benzoxazine monomer and its preparation method", CN106928279A discloses "a bisphenol A-benzoxazine containing bis-DOPO and its preparation method", and 112980135A discloses "flame-retardant-toughened benzoxazine / biobased phosphide composite material and its preparation method", which introduces DOPO (DOPO is the abbreviation of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), DOPO-HQ [DOPO-HQ is the abbreviation of 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide] and biobased phosphide and the like phosphorus-containing groups into the benzoxazine resin to improve the flame retardance of the resin. In order to improve the dielectric property, CN107522831A discloses "a new type of high-temperature-resistant low-dielectric silicon-containing benzoxazine and its preparation method", CN112062908A discloses "a low-dielectric unsaturated benzoxazine resin composition and a preparation method thereof", and CN112142682A discloses "a biphenyl type benzoxazine and its preparation method and polybenzoxazine resin", which introduces silicon, unsaturated bond, biphenyl structure and the like groups into the structure of benzoxazine resin to improve the dielectric property. The above-mentioned technical solutions basically only focus on the improvement of one aspect or two aspects of the performance of benzoxazine resin, and there are few patents that have the comprehensive performance of improving heat resistance, dielectric property and flame retardance. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a high-heat-resistant, high-flame-retardant and low-dielectric benzoxazine resin and a preparation method thereof. According to the present application, first, a bisphenol compound, a diamine compound, paraformaldehyde and a catalyst are reacted at a certain temperature, and when the molecular weight of the product reaches a certain degree, a monophenol is added to terminate the reaction, forming a main chain type benzoxazine resin; then the benzoxazine resin is reacted with DOPO at a certain temperature, thereby providing a benzoxazine resin and a preparation method thereof, which have the performances of high heat resistance, high flame retardance and low dielectricity.

[0005] The content of the present application is: a high heat resistance, high flame retardant, low dielectric benzoxazine resin, characterized in that: the benzoxazine resin has a chemical formula as shown in formula (1):

[0006]

[0007] In formula (1): n is 0-10,

[0008] R1 is -CH2-, -SO2, -O-, -CO-;

[0009] R2 is -CH2-, -SO2, -C(CH3)2-, -C(CH3)(C2H5)-, -C(CF3)2-, -CH(CH3)-

[0010]

[0011] R3 is -H, -CH3, -CH2CH=CH2;

[0012] R4 is -H, C1-C 12 alkyl, -CH=CH2, -CH2CH=CH2, -C6H5, -NH2, -NO2, -C 10 H7

[0013] or -C6H 11 .

[0014] Another content of the present application is: a preparation method of a high heat resistance, high flame retardant, low dielectric benzoxazine resin, characterized in that the steps are: in a reactor provided with a stirrer, a thermometer and a condenser, 100g of main chain type benzoxazine resin, 17-28g of DOPO and 100g of solvent are added, the temperature is raised to 80-100℃, and reacted for 30-100min; then the temperature is adjusted to 100-120℃, and reacted for 30-100min, and then cooled, to obtain a high heat resistance, high flame retardant, low dielectric benzoxazine resin;

[0015] The main chain type benzoxazine resin has a chemical formula as shown in formula (2):

[0016]

[0017] In formula (2): n is 0-10;

[0018] R1 is -CH2-, -SO2, -O-, -CO-;

[0019] R2 is -CH2-, -SO2, -C(CH3)2-, -C(CH3)(C2H5)-, -C(CF3)2-, -CH(CH3)-

[0020]

[0021] R3 is -H, -CH3, -CH2CH=CH2;

[0022] R4 is -H, C1-C 12 alkyl, -CH=CH2, -CH2CH=CH2, -C6H5, -NH2, -NO2, -C 10 H7

[0023] or -C6H 11 ;

[0024] The DOPO is purchased from Shouguang Weidong Co., Ltd. or other enterprises;

[0025] The solvent is one of butanone, toluene, cyclohexanone, propylene glycol monomethyl ether, propylene glycol methyl ether acetate, N, N-dimethylformamide, N, N-dimethylacetamide, methyl isobutyl ketone or a mixture of two or more thereof;

[0026] In another content of the present application: the preparation method of the main chain type benzoxazine resin is as follows: in a reactor provided with a stirrer, a thermometer, a condenser and a water separator, a bisphenol compound, a diamine compound and paraformaldehyde are added in a molar ratio of 1:1.1-1.5:2.5-4, then toluene with a weight of 1-3 times the total mass of the mixture (the total mass of the mixture is the total mass of the bisphenol compound, the diamine compound and the paraformaldehyde) and a catalyst with a weight of 1 ‰-1% of the total weight of the material (the total weight of the material is the sum of the total mass of the mixture and the weight of toluene) are added, the mixture is stirred uniformly, heated to 60-90 ℃ (temperature 1), reacted for 0.5-4 h (time 1), and the water generated in the reaction is taken out of the system in time by using the water separator, reacted at 110-130 ℃ (temperature 2) for 0.5-2 h (time 2); the molecular weight of the resin is tested, after the target molecular weight is reached, 0.2-0.5 mol of monophenol is added, and the reaction is continued at 110-130 ℃ for 1-3 h (time 3); the obtained resin (i.e. the material after reaction) is washed with a 1 mol / L NaOH solution, separated into layers, the lower resin layer is taken out, washed with deionized water, separated into layers, the lower resin layer is taken out, and toluene and water are removed by using a rotary evaporator to obtain the main chain type benzoxazine resin;

[0027] The bisphenol compound is one of bisphenol A, bisphenol F, bisphenol C, 4,4'-dihydroxy diphenyl ether, bisphenol S, bisphenol AF, bisphenol B, bisphenol fluorene, phenolphthalein, bisphenol TMC, bisphenol E, bisphenol M, tetraphenyl bisphenol A or a mixture of two or more thereof;

[0028] The diamine compound is one of diamino diphenyl methane, diamino diphenyl ether, diamino diphenyl sulfone, diamino benzophenone or a mixture of two or more thereof;

[0029] The monophenol is a compound having a chemical structure shown in the following formula (3):

[0030]

[0031] R5 is -H, -C1~C 12 alkyl, -CH=CH2, -CH2CH=CH2, -C6H5, -NH2, -NO2, -C 10 H7

[0032] or -C6H 11 ;

[0033] The paraformaldehyde is one or a mixture of two or more thereof having a polymerization degree of 10-100, and the number of moles is calculated according to the number of moles of theoretical formaldehyde, i.e. the number of moles = mass x purity ÷ 30;

[0034] The catalyst is one or a mixture of two or more thereof of zinc chloride, indium trihalide, ferric chloride, antimony pentachloride, triflate, morpholine trifluoroacetate, aluminum trichloride-nitroalkyl complex and other metal halides.

[0035] Compared with the prior art, the present application has the following characteristics and beneficial effects:

[0036] (1) The high heat-resistant, high flame-retardant and low dielectric benzoxazine resin of the present application uses part of the oxazine rings in the ring-opening main chain type benzoxazine resin structure of DOPO (P-H bond) to obtain a benzoxazine resin with high phosphorus content, and the phosphorus content is 2-3%, and the P-N synergy greatly improves the flame retardancy of the resin;

[0037] (2) The high heat-resistant, high flame-retardant and low dielectric benzoxazine resin of the present application contains a main chain type benzoxazine resin structure, which has a long molecular main chain, and the oxazine rings are all fixed on the main chain. When the oxazine ring is opened by heat, a large volume chemical structure is formed with the molecular main chain as the center, which increases the free volume of the molecule, blocks the molecular vibration, and makes the dielectric performance more excellent;

[0038] (3) Compared with ordinary benzoxazine resin, the high heat-resistant, high flame-retardant and low dielectric benzoxazine resin of the present application has more crosslinking points during curing, has a higher crosslinking density, and the molecular groups are all fixed on the main chain without pendant groups, so that the heat resistance of the product is greatly improved;

[0039] (4) The high-heat-resistant, high-flame-retardant, low-dielectric benzoxazine resin has the performance parameters of heat resistance Td5%≥370℃, Tg≥240℃, dielectric constant≤3.20, dielectric loss≤0.006, and flame retardancy reaching UL94 V-0 level, and has the characteristics of high heat resistance, halogen-free flame retardancy, etc., and has excellent comprehensive performance, and can be used as a resin for high-performance copper-clad plates;

[0040] (5) The product has simple preparation process and easy operation, and the high-heat-resistant, high-flame-retardant, low-dielectric benzoxazine resin has the characteristics of halogen-free, high flame retardancy, high heat resistance, good toughness, and good dielectric performance, is particularly suitable for being used as a raw material for high-frequency high-speed copper-clad plates, and can also be used in the fields of laminated boards, integrated circuit packaging, high-density Internet, etc., and has strong practicability. DETAILED DESCRIPTION

[0041] The following examples are intended to further illustrate the present application, but are not to be construed as limiting the scope of the present application, and some non-essential improvements and adjustments made by those skilled in the art to the present application based on the content of the present application still fall within the protection scope of the present application.

[0042] Preparation of main chain type benzoxazine resin

[0043] Embodiments 1-1 to 1-6: A main chain type benzoxazine resin is prepared by the following steps: in a reactor provided with a stirrer, a thermometer, a condenser and a water separator, a bisphenol compound, a diamine compound and paraformaldehyde are added in a molar ratio of 1:1.1-1.5:2.5-4, and then toluene with a weight of 1-3 times the total weight of the mixture (the total weight of the mixture is the total weight of the bisphenol compound, the diamine compound and the paraformaldehyde) and a catalyst with a weight of 1 ‰-1% of the total weight of the materials (the total weight of the materials is the sum of the total weight of the mixture and the weight of toluene) are added, the mixture is stirred uniformly, heated to 60-90℃ (temperature 1), reacted for 0.5-4h (time 1), and the water generated in the reaction is removed from the system in time by using the water separator, and then reacted at 110-130℃ (temperature 2) for 0.5-2h (time 2); the molecular weight of the resin is tested, and when the target molecular weight is reached, 0.2-0.5 mol of a monophenol is added, and the reaction is continued at 110-130℃ for 1-3h (time 3); the obtained resin (i.e. the material after reaction) is washed with a 1 mol / L NaOH solution, and the lower resin layer is separated, then washed with deionized water, and the lower resin layer is separated, and toluene and water are removed by using a rotary evaporator to obtain a main chain type benzoxazine resin;

[0044] The bisphenol compound is one or a mixture of two or more of the following: bisphenol A, bisphenol F, bisphenol C, 4,4'-dihydroxydiphenyl ether, bisphenol S, bisphenol AF, bisphenol B, bisphenol fluorene, phenolphthalein, bisphenol TMC, bisphenol E, bisphenol M, and tetraphenylbisphenol A.

[0045] The diamine compound is one or a mixture of two or more of diaminodiphenylmethane, diaminodiphenyl ether, diaminodiphenyl sulfone, and diaminodibenzophenone;

[0046] The monophenol is a compound having the chemical structure shown in formula (3) below:

[0047]

[0048] R5 represents -H, -C1 to C. 12 Alkyl groups, -CH=CH2, -CH2CH=CH2, -C6H5, -NH2, -NO2, -C 10 H7

[0049] or -C6H 11 ;

[0050] The degree of polymerization of the paraformaldehyde can be one or more of the following: 10-100. The number of moles is calculated according to the theoretical number of formaldehyde moles, i.e., number of moles = mass × purity ÷ 30. The paraformaldehyde used in Examples 1-1 to 1-6 is analytical grade granular paraformaldehyde from Merck Chemicals with a purity of 95%.

[0051] The catalyst is one or a mixture of two or more metal halides such as zinc chloride, indium trihalide, ferric chloride, antimony pentachloride, trifluoromethanesulfonate, morpholine trifluoroacetate, and aluminum trichloride-nitroalkyl complex.

[0052] The specific components, amounts, and process parameters of each example in the preparation methods of the main-chain benzoxazine resins in Examples 1-1 to 1-6 are shown in Table 1 below.

[0053] Table 1:

[0054]

[0055]

[0056] Part Two: Preparation of High Heat Resistance, High Flame Retardancy, and Low Dielectric Benzoxazine Resin

[0057] Embodiment 2-1~2-6: A method for preparing a high-heat-resistant, high-flame-retardant, and low-dielectric benzoxazine resin, comprising the following steps: adding 100 g of main-chain type benzoxazine resin (the main-chain type benzoxazine resin prepared in Embodiments 1-1~1-6, see Table 2 below for details), 17~28 g of DOPO, and 100 g of solvent into a reactor equipped with a stirrer, a thermometer, and a condenser, and heating to 80~100°C (temperature 4), and reacting for 30~100 min (time 4); then adjusting the temperature to 100~120°C (temperature 5), and reacting for 30~100 min (time 5), and cooling, to obtain the high-heat-resistant, high-flame-retardant, and low-dielectric benzoxazine resin.

[0058] Table 2 below shows the specific components, amounts, process parameters, and performance parameters of the high-heat-resistant, high-flame-retardant, and low-dielectric benzoxazine resin prepared in Embodiments 2-1~2-6.

[0059] Table 2:

[0060]

[0061]

[0062] The technical performance test methods in Table 2 are as follows:

[0063] (1) Glass transition temperature (Tg)

[0064] According to the differential scanning calorimetry method, the DSC method specified in IPC-TM-650 2.4.25 was used for determination.

[0065] (2) Thermal decomposition temperature (Td)

[0066] The method specified in IPC-TM-650 2.4.26 was used for determination.

[0067] (3) Flame retardancy

[0068] The test was performed using a 5402 horizontal and vertical burning tester according to the test method in GB / T 1303.2-2009 Part 2.

[0069] (4) Phosphorus content (P%)

[0070] The test was performed using the SGS internal test method (CQTC-CCL-TOP-001, referring to US EPA 3052-1996), and ICP-OES was used for analysis.

[0071] (5) Dielectric constant (Dk)

[0072] The dielectric constant at 10 GHz is determined according to IPC-TM-650 2.5.5.9 using the plate method.

[0073] (6) Medium loss factor tangent (Df)

[0074] The medium loss factor tangent at 10 GHz is determined according to IPC-TM-650 2.5.5.9 using the plate method.

[0075] As shown in Table 2, the high-heat-resistant, high-flame-retardant, low-dielectric benzoxazine resin obtained by using the embodiments of the present application has excellent heat resistance, high flame retardancy. The resin of the present application can be used in the fields of laminated boards, integrated circuit packaging, high-frequency high-speed copper-clad boards, high-density Internet, etc., and has a broad application prospect.

[0076] In the above embodiments: in the percentage, unless otherwise specified, it is the mass (weight) percentage or the percentage known to those skilled in the art; in the proportion, unless otherwise specified, it is the mass (weight) proportion; the weight parts can all be grams or kilograms.

[0077] In the above embodiments: the process parameters (temperature, time, concentration, etc.) and the amount of each component in each step are ranges, and any point can be applicable.

[0078] The technical content not specifically described in the above embodiments and the present application is the same as the prior art, and the raw materials are all commercially available products.

[0079] The present application is not limited to the above embodiments, and all the contents described in the present application can be implemented and have the good effects described.

Claims

1. A benzoxazine resin, characterized in that: The benzoxazine resin has the chemical structural formula shown in formula (1): In equation (1): n is 0 to 10, R1 is -CH2- or -O-; R2 can be -CH2-, -SO2-, -C(CH3)2-, -C(CH3)(C2H5)-, or -CH(CH3)-. R3 is -H or -CH3; R4 represents -H, -C1 to C 12 Alkyl groups.

2. A method for preparing a benzoxazine resin, characterized by the following steps: adding 100g of main-chain benzoxazine resin, 17-28g of DOPO, and 100g of solvent to a reactor equipped with a stirrer, thermometer, and condenser; heating to 80-100℃ and reacting for 30-100min; then adjusting the temperature to 100-120℃ and reacting for 30-100min; cooling down to obtain a high heat-resistant, high flame-retardant, and low dielectric benzoxazine resin; The main-chain benzoxazine resin has the chemical structural formula shown in formula (2): In equation (2): n is 0 to 10; R1 is -CH2- or -O-; R2 can be -CH2-, -SO2-, -C(CH3)2-, -C(CH3)(C2H5)-, or -CH(CH3)-. R3 is -H or -CH3; R4 represents -H, -C1 to C 12 Alkyl groups.

3. The method for preparing the benzoxazine resin according to claim 2, characterized in that: The solvent is one or a mixture of two or more of the following: butanone, toluene, cyclohexanone, propylene glycol monomethyl ether, propylene glycol methyl ether acetate, N,N-dimethylformamide, N,N-dimethylacetamide, and methyl isobutyl ketone.

4. The method for preparing the benzoxazine resin according to claim 2 or 3, characterized in that: The preparation method of the main-chain benzoxazine resin is as follows: In a reactor equipped with a stirrer, thermometer, condenser, and water separator, bisphenol compound, diamine compound, and paraformaldehyde in a molar ratio of 1:1.1-1.5:2.5-4 are added. Then, toluene (1-3 times the total mass of the mixture) and catalyst (1‰-1% of the total weight of the materials) are added. The mixture is stirred evenly, heated to 60-90℃, and reacted for 0.5-4 hours. The reaction is then carried out using a water separator. The apparatus promptly removes the water produced during the reaction from the system, and the reaction is carried out at 110–130℃ for 0.5–2 hours. The molecular weight of the resin is tested, and once the target molecular weight is reached, 0.2–0.5 mol of monophenol is added, and the reaction is continued at 110–130℃ for 1–3 hours. The obtained resin is washed and separated with 1 mol / L NaOH solution, and the lower resin layer is removed. It is then washed and separated with deionized water, and the lower resin layer is removed. Toluene and water are removed using a rotary evaporator to obtain the main-chain benzoxazine resin. The bisphenol compound is one or a mixture of two of bisphenol F and bisphenol S; The diamine compound is one or a mixture of two of diaminodiphenylmethane and diaminodiphenyl ether; The monophenol is a compound having the chemical structure shown in formula (3) below: R5 represents -H, -C1 to C. 12 Alkyl groups.

5. The method for preparing the benzoxazine resin according to claim 4, characterized in that: The paraformaldehyde is one or more mixtures of two or more compounds with a degree of polymerization of 10-100.

6. The method for preparing the benzoxazine resin according to claim 4, characterized in that: The catalyst is one or a mixture of two or more of zinc chloride, indium trihalide, ferric chloride, antimony pentachloride, trifluoromethanesulfonate, morpholine trifluoroacetate, and aluminum trichloride-nitroalkyl complex.

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