CN115286794A

CN115286794A - Maleimide resin and synthetic method thereof

Info

Publication number: CN115286794A
Application number: CN202211018369.6A
Authority: CN
Inventors: 张驰; 张朝军; 张治�; 邓凯华; 江信求
Original assignee: Tongyu New Material Guangdong Co ltd
Current assignee: Tongyu New Material Guangdong Co ltd
Priority date: 2022-08-24
Filing date: 2022-08-24
Publication date: 2022-11-04

Abstract

The invention provides a maleimide resin and a synthesis method thereof, relating to the technical field of resin materials. A maleimide resin represented by the following formula, wherein n is not less than 0; the maleimide resin with multifunctionality and branched structure is prepared by mixing maleic anhydride and primary amine with triphenylmethane multifunctionality structure in a mixed solution. Compared with the traditional bismaleimide resin, the multifunctional maleimide resin containing branched chains has better solubility, higher flame retardant property, better rheological processing property, mechanical property and heat resistance. Can make up the deficiency of the bismaleimide resin and broaden the application of the maleimide resin in the electronic and electric industry, high-temperature adhesives and laminated board matrixes.

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Description

Maleimide resin and synthetic method thereof

Technical Field

The invention belongs to the technical field of resin materials, and particularly relates to a maleimide resin and a synthetic method thereof.

Background

The maleimide resin is mostly a difunctional bismaleimide resin (BMI) which is a difunctional compound having its Maleimide (MI) as a reactive end group and generally has the following structure:

wherein R is at least one selected from aromatic benzene ring and aliphatic long-chain framework.

When R is a benzene ring structure, the bismaleimide resin has strong crystallinity and a high melting point. If there is no substituent group on the benzene ring, the solubility is poor, and the solvent can only be dissolved in a few strong polar solvents, which brings about inconvenience for processing. Further, a material formed by self-polymerization of pure bismaleimide is brittle and has poor mechanical properties. Therefore, when a bismaleimide resin is used, toughening modification is generally performed on the bismaleimide resin. The currently successful modification methods are diallyl bisphenol A modified bismaleimide resin and aromatic diamine modified bismaleimide resin. I.e. the pure resin is chain extended, thereby reducing the crosslink density of the resin. Compared with pure resin, the toughness of the modified resin after chain extension is greatly improved. The bismaleimide resin modified by the methods is widely applied to matrix resin of fiber composite materials, packaging materials, aerospace, electronic and electrical products and other industries.

When R is an aliphatic skeleton, the bismaleimide resin has a lower melting point, has a higher solubility in an organic solvent, and has a lower dielectric constant after curing, but the Tg of the polymer is lower, and the polymer has a lower heat resistance and a lower flame retardant property. However, when one or more aromatic bismaleimide monomers are used in combination with aliphatic bismaleimide monomers to prepare bismaleimide resin prepolymers, whether a solvent system or a solvent-free system is adopted, the bismaleimide resin prepolymers have the problem that the bismaleimide monomers are precipitated due to different solubilities, and the stability and the validity period of the bismaleimide resin prepolymers are affected.

Chinese patent CN11788176A discloses a compound, a resin, a composition and a film forming material for lithography using the same, and discloses a compound represented by the following formula R ^1A At least 1 of the above groups is any one of a C4-30 maleimido group optionally having a substituent and a C4-30 maleimido group optionally having a substituent, X represents an oxygen atom or a sulfur atom, or is absent, R independently represents any one of a benzene ring, a naphthalene ring and an anthracene ring, m independently represents an integer of 0 to 9, wherein at least 1 of m is an integer of 1 to 9, and n is an integer of 1 to 9 ^A Is an integer of 1 to 4. The prepared (poly) imide compound and (poly) amic acid compound have excellent solubility in ethyl acetate, and the modified resin has good film heat resistance, film corrosion resistance, film embedding property and flatness.

Chinese invention patent CN10398770A discloses a maleimide resin comprising both a maleimide component containing an aryl sulfone and a polyaryl polymer thermoplastic toughening agent component. Have high toughness and good modulus, and have good thermal properties (including high Tg, good thermal oxidative stability, and high temperature durability).

At present, no matter the bismaleimide with a benzene ring structure is toughened and modified, or the bismaleimide with an aliphatic group is used in a matching way, the problems of complex processing steps, difficult processing and the like exist. The problem to be solved is to research a maleimide resin with low softening point and high cohesiveness.

Disclosure of Invention

The invention provides a maleimide resin and a synthesis method thereof aiming at the problems in the prior art, and aims to solve the problems of low solubility, strong crystallinity, high melting point, easy precipitation, poor mechanical property after curing, poor flame retardance and the like of the traditional bismaleimide resin.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

first, the present invention provides a maleimide resin represented by the following formula,

wherein n is more than or equal to 0.

Preferably, n =0-10 of the maleimide resin.

Further preferably, n =0, 1,2 of the maleimide resin.

Secondly, the invention provides a maleimide resin intermediate of the maleimide resin, the structural formula is shown as the following formula,

wherein n has the same meaning as previously described.

Furthermore, the present invention provides a method for synthesizing the above maleimide resin, comprising the steps of:

(1) Dissolving triphenylmethane polyfunctionality primary amine by using a mixed solvent to obtain a mixed solution 1;

(2) Uniformly mixing maleic anhydride, a catalyst and a solvent to obtain a mixed solution 2;

(3) Reacting the mixed solution 1 with the mixed solution 2 to obtain a reaction mixture;

(4) The reaction mixture was subjected to a post-treatment to obtain a maleimide resin.

Preferably, the structural formula of the triphenylmethane multifunctional primary amine in the step (1) is shown as the following formula:

wherein n has the same meaning as previously described.

Further preferably, the triphenylmethane multifunctional primary amine is at least one selected from the group consisting of triphenylmethane diamine monomer and triphenylmethane amine polymer.

Further preferably, the triphenylmethane polyfunctional primary amine is a triphenylmethane amine polymer.

Further preferably, the polymerization degree of the triphenylmethane amine polymer is 0 to 10.

Most preferably, the polymerization degree of the triphenylmethane amine polymer is 0 to 2.

Preferably, the mixed solvent in step (1) is selected from at least two of N, N-Dimethylformamide (DMF), dimethylacetamide (DMAC), toluene, benzene, xylene, methyl isobutyl ketone (MIBK).

Further preferably, the mixed solvent is selected from at least two of N, N-dimethylformamide, dimethylacetamide, toluene, and methyl isobutyl ketone.

Still more preferably, the mixed solvent is a mixed solvent of N, N-dimethylformamide and toluene.

Preferably, in the step (1), the mass ratio of the mixed solvent is 1.

Further preferably, the mass ratio of the mixed solvent is 1.

Preferably, in the step (1), the concentration of the triphenylmethane multifunctional primary amine in the mixed solvent is 5-50%.

Further preferably, the concentration of the triphenylmethane polyfunctional primary amine in the mixed solvent is 33%.

Preferably, in the step (2), the catalyst is at least one selected from concentrated sulfuric acid, p-toluenesulfonic acid, methanesulfonic acid, phosphoric acid and trifluoromethanesulfonic acid.

Further preferably, the catalyst is selected from one of concentrated sulfuric acid, p-toluenesulfonic acid, methanesulfonic acid and phosphoric acid.

Even more preferably, the catalyst is p-toluenesulfonic acid.

Preferably, the solvent in step (2) is at least one selected from the group consisting of N, N-Dimethylformamide (DMF), dimethylacetamide (DMAC), toluene, benzene, xylene, and methyl isobutyl ketone (MIBK).

Further preferably, the solvent is selected from at least one of N, N-dimethylformamide, toluene, benzene, xylene and most preferably, the solvent is toluene.

Preferably, in the step (3), the reaction is specifically: and (3) at the temperature of 20-120 ℃, dropwise adding the mixed solution 1 into the mixed solution 2 for 2-4h, and continuously carrying out reflux reaction for 5-10h.

Further preferably, in the step (3), the reaction is specifically: and (3) at the temperature of 110 ℃, dropwise adding the mixed solution 1 into the mixed solution 2 for 2-4h, and continuously carrying out reflux reaction for 6-7h.

Preferably, the molar ratio of the triphenylmethane multifunctional primary amine to the maleic anhydride is 1.

Further preferably, the molar ratio of the triphenylmethane multifunctional primary amine to the maleic anhydride is 1.

Preferably, in the step (4), the post-treatment specifically comprises: washing with water, adjusting pH, and reacting with a polymerization inhibitor.

Further preferably, the water washing specifically comprises: mixing the reaction mixture with water, stirring at 0-90 deg.C for 20-60min, standing to remove the lower water layer.

Still more preferably, the water washing is specifically: mixing the reaction mixture with water, stirring at 70-80 deg.C for 30-40min, standing to remove the lower water layer.

Further preferably, the adjusting pH specifically is: after adjusting the pH to 8-9 with a base, the above water washing step is repeated 2-4 times.

Still more preferably, the alkali is at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium bicarbonate, and has a concentration of 30 to 60%.

Still more preferably, the base is 40% aqueous sodium hydroxide.

Further preferably, the polymerization inhibitor reaction specifically comprises: and (3) carrying out reduced pressure reaction on the mixture after pH adjustment and a polymerization inhibitor at 100-130 ℃ for 1-180min, wherein the molar ratio of the polymerization inhibitor to the triphenylmethane polyfunctional primary amine is 0.00001-0.01.

More preferably, the polymerization inhibitor reaction specifically comprises: and (3) carrying out reduced pressure reaction on the mixture after pH adjustment and a polymerization inhibitor at 110-120 ℃ for 120min, wherein the molar ratio of the polymerization inhibitor to the triphenylmethane polyfunctional primary amine is 0.0001-0.001.

Still more preferably, the polymerization inhibitor is selected from at least one of beautiful jade, hydroquinone, tetrachlorobenzoquinone and methylhydroquinone.

Still more preferably, the polymerization inhibitor is selected from at least one of beautiful jade, hydroquinone and hydroquinone.

Still more preferably, the polymerization inhibitor is hydroquinone.

Finally, the invention provides the application of the maleimide resin or the intermediate of the maleimide resin in preparing flame-retardant materials, electronic and electric products, high-temperature adhesives and laminated plate substrates.

Compared with the prior art, the invention has the following beneficial effects:

1. according to the invention, triphenylmethane polyfunctionality primary amine reacts with maleic anhydride to synthesize triphenylmethane polyfunctionality maleimide resin, and the resin has the characteristics of low softening point, good solubility, good processing rheological property, difficulty in precipitation from a system, and high flame retardant property and heat resistance;

2. the preparation method of the invention simplifies the modification process of the maleimide resin and effectively overcomes the defects of complex process of the traditional bismaleimide resin synthesis method.

Drawings

FIG. 1 is an infrared spectrum of a maleimide resin prepared in example 1 of the present invention;

FIG. 2 is an infrared spectrum of a maleimide resin prepared in example 2 of the present invention;

FIG. 3 is an infrared spectrum of a maleimide resin prepared in example 3 of the present invention;

FIG. 4 is an infrared spectrum of a maleimide resin of example 4 of the present invention;

FIG. 5 is an infrared spectrum of a maleimide resin prepared in example 5 of the present invention;

FIG. 6 is a differential scanning calorimetry spectrum of a maleimide resin prepared in example 1 of the present invention;

FIG. 7 is a differential scanning calorimetry trace of a maleimide resin prepared in example 2 of the present invention;

FIG. 8 is a differential scanning calorimetry spectrum of a maleimide resin prepared in example 4 of the present invention;

FIG. 9 is a differential scanning calorimetry spectrum of a maleimide resin of comparative example 1 of the present invention;

FIG. 10 is a differential scanning calorimetry spectrum of the maleimide resin of comparative example 2 of the present invention.

Detailed Description

The following non-limiting examples will provide those of ordinary skill in the art with a more complete understanding of the present invention, but are not intended to limit the invention in any way. The following is merely an exemplary illustration of the scope of the claims of the present application and various changes and modifications of the invention of the present application may be made by those skilled in the art based on the disclosure, which should also fall within the scope of the claims of the present application.

The present invention will be further described below by way of specific examples. The various chemicals used in the examples of the present invention were obtained by conventional commercial routes unless otherwise specified. The contents are all mass contents hereinafter.

In the examples described below, the triphenylmethane polyfunctional aromatic primary amine is available from Jiangsu Jalin chemical Co., ltd.; n, N-dimethylformamide, toluene and methyl isobutyl ketone are all bottled reagents which are purchased from national drug group chemical reagent company Limited; maleic anhydride was purchased from (Yunnan, chemical Co., ltd.); hydroquinone (polymerization inhibitor) was purchased from (Tianjin Daloc chemical Agents).

w1: weight of synthesized product; w2: theoretical weight of synthesized product.

The purity determination method comprises the following steps: the measurement is carried out by adopting High Performance Liquid Chromatography (HPLC), and the HPLC conditions are as follows: aigilent1260 high performance liquid chromatograph; and (3) chromatographic column: c18; mobile phase: acetonitrile and water; elution procedure: gradient elution, starting with water as mobile phase: acetonitrile =20, gradient change for 30min is 80; flow rate: 1mL/min; column temperature: 45 ℃; sample injection volume: 10 mu L of the solution; a detector: an ultraviolet detector with the detection wavelength of 254nm; data acquisition time: and (5) 30min. Sample preparation: the solvent was acetonitrile, and a sample solution with a concentration of 0.1% was prepared.

Infrared spectroscopy test (FTIR): infrared ATR method.

Example 1

A triphenylmethane polyfunctional maleimide resin prepared according to the following reaction formula:

the specific reaction steps are as follows:

1mol of triphenylmethane polyfunctional primary aromatic amine, n =1 (functionality equal to 3.0), was dissolved in a mixed solvent of 400g of DMF and 800g of toluene. Adding 62.5g of p-toluenesulfonic acid and 750g of toluene into a reaction kettle, stirring, heating to 110 ℃, keeping toluene refluxing, and removing catalyst and residual water in the toluene by using a condensation water-separating device;

after the materials in the reaction kettle are completely dehydrated, adding 300g of maleic anhydride, continuously heating and refluxing at 110 ℃, dripping the dissolved triphenylmethane multifunctional primary amine into the reaction kettle while refluxing, and controlling the dripping within 3 hours to be finished;

after the dropwise addition is finished, the reaction kettle is continuously heated and refluxed for 6 hours at the temperature of 110 ℃, and water is removed by a condensation and water distribution device; after the reaction is finished, cooling to 80 ℃, adding 800g of clear water into the reaction kettle, stirring at 75 ℃ for washing for 30min, standing for 30min, and separating a lower water layer; then adding 400g of clear water into the reaction kettle, dropwise adding 40% sodium hydroxide solution to adjust the pH value of the materials in the reaction kettle to 8, stirring at 75 ℃ for washing for 30min, standing for 30min, and removing a lower water layer; then, the water washing layering process is repeated twice by using deionized water;

filtering the washed material into a clean reaction kettle while the material is hot, adding 0.001mol of hydroquinone polymerization inhibitor, stirring and vacuumizing, heating at 110 ℃, decompressing and desolventizing, slowly removing the solvent toluene in the kettle until the material is thick and has no solvent removed, and cooling to obtain the product, namely the maleimide resin 674g, wherein the yield is 97 percent and the purity is 99.5 percent.

The obtained product maleimide resin was subjected to infrared spectroscopic measurement, and the measurement results are shown in FIG. 1: 1705cm can be seen from the figure ^-1 The absorption peak has a very strong sharp absorption peak corresponding to the carbonyl absorption peak of maleimide, which indicates that the maleimide resin is successfully prepared and is 2900-3100cm ^-1 At a distance of 3500cm ^-1 The absorption peaks at the left and right (corresponding to the absorption peaks of the amino group and the hydroxyl group as the intermediate products) were very weak and almost none, and it was also confirmed that the intermediate products having no ring closure were very few and almost none in the resin.

Example 2

the specific reaction steps are as follows:

unlike example 1, triphenylmethane polyfunctional primary aromatic amine has n =2 (functionality of 4), and the rest is the same. 870g of the product maleimide resin was obtained in 91% yield and 97.7% purity.

The obtained product maleimide resin was subjected to infrared spectroscopic test, and the test results are shown in FIG. 2: 1709cm can be seen from the figure ^-1 The absorption peak has a strong and sharp absorption peak corresponding to the carbonyl absorption peak of maleimide, which indicates that the maleimide resin is successfully prepared and is 2900-3100cm ^-1 At a height of 3500cm ^-1 The absorption peaks at the left and right (corresponding to the absorption peaks of the amino group and the hydroxyl group of the intermediate product) have weaker absorption, which proves that a small amount of intermediate product which is not subjected to complete ring closure exists in the resin, and the ring closure reaction is not complete probably because the steric hindrance effect begins to appear in the molecular structure along with the increase of the polymerization degree n.

Example 3

the specific reaction steps are as follows:

unlike example 1, the triphenylmethane polyfunctional primary aromatic amine has n =3 (functionality of 5), and the rest is the same. 1071g of the maleimide resin was obtained in 88% yield and 95% purity.

The obtained product maleimide resin was subjected to infrared spectroscopic measurement, and the measurement results are shown in FIG. 3, from which: at 1716cm ^-1 The absorption peak corresponds to the carbonyl absorption peak of maleimide, which indicates that the maleimide resin is successfully prepared and is 2900-3100cm ^-1 At a distance of 3500cm ^-1 The absorption peaks at the left and right (corresponding to the absorption peaks of amino and hydroxyl of the intermediate product) show relatively obvious strong absorption, which proves that a large amount of intermediate products without closed rings exist in the resin, the purity of the product is lower, and the closed rings are influenced by further increase of steric hindrance in the molecular structure along with increase of polymerization degree n.

Example 4

A triphenylmethane diamine maleimide resin (n =0, functionality of 2) prepared according to the following reaction scheme:

the specific reaction steps are as follows:

275g of triphenylmethanediamine monomer were dissolved in 275g of DMF and 275g of toluene. Adding 50g of p-toluenesulfonic acid and 600g of toluene into a reaction kettle, stirring, heating to 110 ℃, keeping toluene refluxing, and removing catalyst and residual water in the toluene by using a condensation water separator;

after the materials in the reaction kettle are completely dehydrated, adding 200g of maleic anhydride, then continuing heating reflux at 110 ℃, dripping the dissolved triphenylmethane diamine into the reaction kettle while refluxing, and controlling the dripping within 2.5 hours to be finished;

after the dropwise addition, the reaction kettle is continuously heated and refluxed at 110 ℃ for 6 hours, and water is removed by a condensation and water distribution device. After the reaction is finished, cooling to 80 ℃, adding 550g of clear water into the reaction kettle, stirring and washing at 76 ℃ for 30min, standing for 30min, and separating a lower water layer; then adding 400g of clear water again and dripping 40% of sodium hydroxide solution to adjust the pH value of the materials in the kettle to 8, stirring and washing the materials for 30min at 76 ℃, standing for 30min, and separating a lower water layer; then, the deionized water is used for repeating the water washing layering process twice;

filtering the washed material into a clean reaction kettle while the material is hot, stirring in vacuum, heating at 120 ℃ and decompressing to remove the solvent, slowly removing the solvent toluene in the kettle until the material is thick, removing no solvent, and cooling to obtain 416.3g of the product maleimide resin, wherein the yield is 96 percent and the purity is 99.5 percent.

The obtained product maleimide resin was subjected to infrared spectroscopic measurement, and the measurement results are shown in FIG. 4, from which: at 1709cm ^-1 The absorption peak has a strong sharp absorption peak corresponding to the carbonyl absorption peak of maleimide, which indicates that the maleimide resin is successfully prepared and is 2900-3100cm ^-1 At a distance of 3500cm ^-1 The absorption peaks at the left and right (corresponding to the absorption peaks of the amino group and the hydroxyl group as the intermediate products) are very weak and almost none, and the tree is provedThere are few, if any, intermediate products in the lipid that do not form a ring.

Example 5

A triphenylmethane polyfunctional maleimide resin prepared according to the reaction scheme of example 1:

the specific reaction steps are as follows:

except for the difference from example 1, 400g of N, N-Dimethylformamide (DMF) and 800g of methyl isobutyl ketone (MIBK) were mixed and the rest was the same. The product maleimide resin was obtained in 556g, 80% yield and 84% purity.

The obtained product maleimide resin was subjected to infrared spectroscopic measurement, and the measurement results are shown in FIG. 5: the following are shown from the figure: at 1717cm ^-1 The absorption peak corresponds to the carbonyl absorption peak of maleimide, which indicates that the maleimide resin is successfully prepared and is 2900-3100cm ^-1 At a distance of 3500cm ^-1 The absorption peaks at the left and right (corresponding to the absorption peaks of amino and hydroxyl of intermediate products) show obvious strong absorption, which proves that a large amount of intermediate products without ring closure exist in the resin, and the purity of the product is low. The references show that the ketone and the amine have side reactions to generate a series of complex ketimine compounds. Thereby affecting the formation of the maleimide resin.

Example 6

A triphenylmethane polyfunctional maleimide resin prepared according to the reaction of example 1:

the same as in example 1, except that the mixed solvent was 100gN, N-dimethylformamide and 1000g of toluene. 625g of the maleimide-based resin product was obtained in 90% yield and 98.9% purity.

The product maleimide resin obtained was subjected to infrared spectroscopic testing and found to exhibit properties substantially equivalent to those of example 1: the difference is that the viscosity of the materials in the reaction kettle is too viscous in the synthesis process, the stirring is relatively labored, too much resin is adhered to the inner wall of the kettle, and the overheating and scorching phenomena occur due to insufficient stirring, so that the product yield is slightly low.

Example 7

different from example 1, the polymerization inhibitor is 0.001mol of beautiful jade, and the rest are the same. The product, maleimide resin 669g, was obtained in 96.2% yield and 98.8% purity.

The obtained product maleimide resin is subjected to infrared spectrum test, and the test result shows that: the test results found that the performance was similar to example 1, almost the same: except that naphthoquinone itself had a darker color due to the use of naphthoquinone as a polymerization inhibitor, resulting in a resin having a slightly darker color than that of example 1.

Comparative example 1

A traditional diphenylmethane bismaleimide of the diphenylmethane type, chemical name N, N' -4, 4-diphenylmethane bismaleimide, CAS:13676-54-5, available from sheng yi scientific corporation, having a purity of 99.4%, and having the following structural formula:

the infrared spectrum test of the diphenylmethane bismaleimide shows that the purity of the diphenylmethane bismaleimide is 99.4 percent and the diphenylmethane bismaleimide is of a bismaleimide structure with 4,4 sites.

Comparative example 2

A traditional ethylenediamine-type bismaleimide having the chemical name 1, 2-bismaleimide ethane, CAS:5132-30-9, available from Jusheng chemical Co., ltd, hubei, with a purity of 98.0%, and having the following structural formula:

the infrared spectrum test of the ethylenediamine bismaleimide is carried out, and the test result shows that: the purity was 98.0% and the appearance was orange crystals.

Result detection

1. Softening point detection by Differential Scanning Calorimetry (DSC)

The detection method comprises the following steps: adopting constant-speed programmed heating scanning: scanning from 50 ℃ to 350 ℃, and heating rate is 10 ℃/min.

The results are shown in table 1 and fig. 6 to 10:

TABLE 1

As can be seen from the results of the tests, the triphenylmethane polyfunctional maleimide resins synthesized by the present invention all had a lower softening point than that of comparative examples 1 and 2. Furthermore, the softening points of maleimide resins having different degrees of polymerization are different, and when the degree of polymerization of the triphenylmethane polyfunctional maleimide resin is (n = 1-2), the softening point is the lowest.

2. Solubility detection

The detection method comprises the following steps: and preparing a supersaturated resin solution, standing, accurately weighing the upper layer of dissolved and clarified solution, and measuring the mass of the resin dissolved in the solution by using an oven method to calculate the solubility during saturation.

The results are shown in table 2:

TABLE 2

As seen from the normal temperature solubility test data in Table 2, the solubility of the triphenylmethane multifunctional maleimide resin synthesized by the present invention is much higher than that of the traditional diphenylmethane bismaleimide and ethylenediamine bismaleimide, and the triphenylmethane multifunctional maleimide resin has excellent solubility in different solvents. The maleimide resins with different polymerization degrees have obviously different solubilities in a solvent, and when the polymerization degree of the triphenylmethane multifunctional maleimide resin is (n = 1-2), the solubility performance is the highest. Meanwhile, the maleimide resin with high solubility has low softening point (melting point), which is greatly beneficial to the processing and use of downstream merchants. 3. Testing the performance of the pressed glass fiber copper-clad plate:

the results of the tests are shown in Table 3,

TABLE 3

Wherein Tg is the glass transition temperature; DMA is a dynamic mechanical analyzer, and CTE is a coefficient of thermal expansion; TMA is static thermomechanical analysis; UL94 flame retardant rating, V0, is the flame extinguishment within 30 seconds after two 10 second burn tests on the sample. No combustible can fall off; 2G (Dk/Df) is Dk (dielectric constant), df (dielectric loss) measured using 2G electrical signals; 5G (Dk/Df) is Dk (dielectric constant), df (dielectric loss), measured using a 5G electrical signal; 10G (Dk/Df) is Dk (dielectric constant), df (dielectric loss), measured using 10G electrical signals.

From the performance test of the pressed glass fiber copper-clad plate, the triphenylmethane polyfunctionality maleimide resin synthesized by the invention has higher heat resistance and better flame retardant property than the traditional diphenylmethane bismaleimide and ethylenediamine bismaleimide.

In conclusion: the softening point of the triphenylmethane polyfunctionality maleimide resin synthesized in the embodiment is lower than that of the comparative traditional bismaleimide, and the dissolubility is generally good, so that the triphenylmethane polyfunctionality maleimide resin is greatly beneficial to processing and using. The maleimide resin has a multifunctional structure, so that the curing temperature is higher than that of the traditional aliphatic bismaleimide resin (ethylenediamine bismaleimide), and the maleimide resin has better heat resistance and flame retardant property due to the existence of a branched chain structure.

Finally, it should be noted that the above-mentioned contents are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, and that the simple modifications or equivalent substitutions of the technical solutions of the present invention by those of ordinary skill in the art can be made without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A maleimide resin represented by the following formula,

wherein n is more than or equal to 0.

2. The maleimide resin of claim 1, wherein n =0-10.

3. Maleimide resin according to claim 2, characterized in that n =0, 1, 2.

4. A maleimide resin intermediate of the maleimide resin according to any one of claims 1 to 3, of the formula,

wherein n has the same meaning as in claims 1 to 3.

5. A method for synthesizing a maleimide resin according to any one of claims 1 to 3, comprising the steps of:

(1) Dissolving triphenylmethane multifunctional primary amine in a mixed solvent to obtain a mixed solution 1;

6. The method of claim 5, wherein the triphenylmethane multifunctional primary amine in step (1) is at least one member selected from the group consisting of triphenylmethane diamine monomer and triphenylmethane amine polymer.

7. The method of claim 6 wherein the triphenylmethane multifunctional primary amine is a triphenylmethane amine polymer having a degree of polymerization of from 0 to 10.

8. The synthesis method according to claim 5, wherein the mixed solvent in step (1) is at least two selected from the group consisting of N, N-dimethylformamide, dimethylacetamide, toluene, benzene, xylene, and methyl isobutyl ketone.

9. The synthesis method according to claim 8, wherein the mixed solvent is at least two selected from the group consisting of N, N-dimethylformamide, dimethylacetamide, toluene, and methyl isobutyl ketone.

10. The synthesis method according to claim 9, wherein the mixed solvent is a mixed solvent of N, N-dimethylformamide and toluene, and the mass ratio of the mixed solvent to the mixed solvent is 1.

11. The synthesis method according to claim 10, wherein the mass ratio of the N, N-dimethylformamide to the toluene in the mixed solvent is 1.

12. The synthesis method according to claim 5, wherein in the step (2), the catalyst is at least one selected from the group consisting of concentrated sulfuric acid, p-toluenesulfonic acid, methanesulfonic acid, phosphoric acid and trifluoromethanesulfonic acid.

13. The synthesis method according to claim 5, wherein in the step (3), the reaction is specifically: and (3) dropwise adding the mixed solution 1 into the mixed solution 2 at the temperature of 20-120 ℃, completing dropwise adding for 2-4h, and continuously carrying out reflux reaction for 5-10h.

14. The synthesis method according to claim 5, wherein the molar ratio of the triphenylmethane multifunctional primary amine to the maleic anhydride is 1.0-3.6, and the mass ratio of the catalyst to the maleic anhydride is 0.1-1.

15. The synthesis method according to claim 14, wherein the molar ratio of the triphenylmethane multifunctional primary amine to the maleic anhydride is 1.1-2.8, and the mass ratio of the catalyst to the maleic anhydride is 0.25-0.5.

16. The synthesis method according to claim 5, wherein in the step (4), the post-treatment is specifically: washing, adjusting pH and reacting with a polymerization inhibitor; the water washing specifically comprises the following steps: mixing the reaction mixture with water, stirring at 0-90 deg.C for 20-60min, standing to remove the lower water layer; the pH adjustment is specifically as follows: adjusting pH to 8-9 with alkali, and repeating the above washing steps for 2-4 times;

the polymerization inhibitor reaction specifically comprises the following steps: and (3) carrying out a reduced pressure reaction on the mixture after the pH is adjusted and a polymerization inhibitor at 100-130 ℃ for 1-180min, wherein the molar ratio of the polymerization inhibitor to the triphenylmethane polyfunctionality primary amine is 0.00001-0.01.

17. The synthesis method according to claim 16, wherein the polymerization inhibitor is selected from at least one of beautiful jade, hydroquinone, tetrachlorobenzoquinone and methylhydroquinone.

18. Use of the maleimide resin of any one of claims 1 to 3 or the maleimide resin intermediate of claim 4 in the preparation of flame retardant materials, electronic and electrical products, high temperature adhesives, laminate substrates.