Bismaleimide epoxy glass cloth laminated board and production process thereof

Abstract

The invention relates to a bismaleimide epoxy glass cloth laminated board and a production process thereof, and belongs to the technical field of insulating laminated boards. The preparation method comprises the following steps: preparing a bismaleimide epoxy resin prepreg by taking a self-made phosphorus-containing bismaleimide monomer, epoxy resin, tetrahydrofuran, a curing agent and an accelerant as raw materials, dipping alkali-free glass cloth in the prepreg, gluing, laminating, and carrying out hot-pressing curing molding to obtain the bismaleimide epoxy glass cloth laminated board. The phosphorus element is introduced into the bismaleimide monomer, so that the intrinsic flame retardant property of the material is effectively improved, the prepreg with a good flame retardant effect is prepared, and the negative influence on the mechanical property of matrix resin caused by introduction of a large amount of flame retardant is avoided; meanwhile, a long-chain thioether structure is introduced into a bismaleimide monomer structure, so that the toughness and wettability of the bismaleimide resin are effectively improved, the probability of microcracks of a laminated board caused by toughness defects is reduced, and the impact strength of a final product is improved.

Description

Technical Field

[0001] This invention belongs to the field of insulating laminate technology, specifically relating to a bismaleimide epoxy glass cloth laminate and its manufacturing process. Background Technology

[0002] The development of electronic information technology has placed higher demands on the performance of insulating laminates. Among common insulating resins, epoxy resin, the most widely used, has advantages such as low cost, ease of processing, and good adhesion, but it also suffers from drawbacks such as high brittleness, low toughness, and limited heat resistance. Bismaleimide resin possesses excellent heat resistance, mechanical properties, and environmental stability, but it is costly, has a high curing temperature, poor solubility, and high brittleness. Copolymerizing bismaleimide with epoxy resin can combine the advantages of both materials, reducing costs while simultaneously providing the material with heat resistance and ease of processing. However, the problems of high brittleness and low toughness still exist, requiring further modification.

[0003] Furthermore, neither bismaleimide nor epoxy resin is flame-retardant, requiring the addition of flame retardants to prevent property damage and personal injury in the event of a fire. Common inorganic flame retardants and phosphorus-based flame retardants require large amounts to achieve a good flame-retardant effect, which can lead to a loss of the material's mechanical properties. Summary of the Invention

[0004] The purpose of this invention is to provide a bismaleimide epoxy glass cloth laminate and its manufacturing process, in order to solve the problems mentioned in the background art.

[0005] The objective of this invention can be achieved through the following technical solutions: A bismaleimide epoxy glass cloth laminate and its manufacturing process include the following steps: Step 1: Under a nitrogen atmosphere, p-chlorobenzaldehyde, 1,5-pentanedithiol, potassium carbonate, and N,N-dimethylformamide are placed into a three-necked flask pre-equipped with a reflux condenser and a thermometer. Stirring is started, and the mixture is heated to 70-90°C for 8-10 hours. After the reaction is completed, the reaction solution is poured into deionized water, the solid is separated by filtration, washed with deionized water, and dried to obtain the long-chain precursor.

[0006] Step 2: Under ice-water bath conditions, the long-chain precursor, isobutyraldehyde, and the first batch of anhydrous ethanol were added to a three-necked flask pre-equipped with a reflux condenser and a thermometer. Stirring was started, and potassium hydroxide was dissolved in the second batch of anhydrous ethanol and added dropwise to the system. The mixture was heated to 55-60°C and reacted for 5-7 hours. After the reaction was completed, the reaction solution was poured into deionized water to precipitate. The solid was separated by filtration, washed with deionized water and dried, and then recrystallized with anhydrous ethanol to obtain the tetraol intermediate.

[0007] The third step involves adding the tetraol intermediate, phosphorus oxychloride, and aluminum chloride to a three-necked flask pre-equipped with a reflux condenser and a thermometer. The mixture is heated to 70-80°C and kept at that temperature for 6 hours. Then, the temperature is raised to 100-120°C, and stirring is started. The reaction is carried out for 2-4 hours. After the reaction is completed, the solvent is removed by rotary evaporation. The resulting solid is washed with deionized water and dried to obtain the phosphorus-based flame retardant.

[0008] Step 4: Under nitrogen atmosphere and ice-water bath conditions, 4-maleimide-based phenol, triethylamine, and the first batch of tetrahydrofuran were added to a three-necked flask pre-equipped with a reflux condenser and thermometer. Stirring was started, and after 10-12 minutes, the phosphorus-based flame retardant was dissolved in the second batch of tetrahydrofuran and added dropwise to the system. The reaction was carried out at room temperature for 7-10 hours. After the reaction was completed, the residue was removed by suction filtration, and the solvent in the remaining filtrate was removed by rotary evaporation. The obtained solid was washed with deionized water and dried to obtain the phosphorus-containing bismaleimide monomer.

[0009] Step 5: Add phosphorus-containing bismaleimide monomer, epoxy resin, tetrahydrofuran, and curing agent to the reactor, stir and heat to 100~120℃, react for 2~6 hours. After the reaction is completed, lower the system temperature to 45~60℃, add accelerator to the reactor, and stir evenly to obtain bismaleimide epoxy resin prepreg.

[0010] Step 6: Impregnate the alkali-free glass cloth in bismaleimide epoxy resin prepreg, stack the glued glass cloth according to the thickness requirements, and place it in a hot press to hot press and cure to obtain bismaleimide epoxy glass cloth laminate.

[0011] Furthermore, the mass ratio of p-chlorobenzaldehyde, 1,5-pentanedithiol, potassium carbonate and N,N-dimethylformamide used in the first step is 14~15:13~17:2~2.7:170~190.

[0012] Furthermore, the mass ratio of the long-chain precursor, isobutyraldehyde, first batch of anhydrous ethanol, potassium hydroxide, and second batch of anhydrous ethanol used in the second step is 20~23:14~16:40~50:2~3:40~50.

[0013] Furthermore, the mass ratio of the tetraol intermediate, phosphorus oxychloride, and aluminum chloride used in the third step is 25~29:84~88:0.2~0.4.

[0014] Furthermore, the mass ratio of 4-maleimide-based phenol, the first batch of tetrahydrofuran, triethylamine, phosphorus-based flame retardant, and the second batch of tetrahydrofuran used in the fourth step is 12~14:150~160:8~9:24~26:150~160.

[0015] Furthermore, in the fifth step, the mass ratio of phosphorus-containing bismaleimide monomer, epoxy resin, tetrahydrofuran, curing agent, and accelerator is 60~68:62~70:50~80:18~22:0.3~0.6.

[0016] Furthermore, the epoxy resin is at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and phenolic epoxy resin.

[0017] Furthermore, the curing agent is at least one of phthalic anhydride, tung oil anhydride, 4,4'-diaminodiphenylmethane (DDM), and 4,4'-diaminodiphenyl sulfone (DDS).

[0018] Furthermore, the promoter is an imidazole compound, including at least one of 2-methylimidazole, 2-ethyl-4-methylimidazole, and 2-phenylimidazole.

[0019] Furthermore, the adhesive content of the glued glass cloth is 35-50%, preferably 40%.

[0020] Furthermore, the hot-press curing process is carried out at a pressure of 6.5~8MPa, a temperature of 170~185℃, and a time of 200~300min.

[0021] A bismaleimide epoxy glass cloth laminate is prepared by the above preparation steps.

[0022] The beneficial effects of this invention are: 1) This invention uses p-chlorobenzaldehyde and 1,5-pentanedithiol as raw materials to obtain a long-chain precursor via a nucleophilic substitution reaction. Then, using the long-chain precursor and isobutyraldehyde as raw materials, a tetraol intermediate is synthesized via a cross-aldol condensation reaction. This tetraol intermediate then undergoes a nucleophilic substitution reaction with phosphorus oxychloride to form a cyclization ring, yielding a phosphorus-based flame retardant. The phosphorus-based flame retardant is then reacted with 4-maleimide-based phenol via a nucleophilic substitution reaction to synthesize a phosphorus-containing bismaleimide monomer. The phosphorus and nitrogen elements contained in this phosphorus-containing bismaleimide monomer can exert a synergistic flame-retardant effect in both the gas and condensed phases, improving the intrinsic flame-retardant properties of the material.

[0023] 2) Introducing phosphorus-based flame retardants into bismaleimide monomers results in a small dosage and uniform distribution, avoiding the problem of reduced material mechanical properties caused by physical blending of large amounts of phosphorus-based flame retardants, thus enabling the material to maintain better mechanical properties.

[0024] 3) The modifier of the present invention has a long-chain thioether structure, which can increase the molecular chain length of the monomer. The thioether bond increases the flexibility and spin of the chain, reduces the crosslinking density of the polymer network after curing, improves the toughness of the bismaleimide material, and can improve its brittleness. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0027] It should be understood that the use of “including,” “having,” or “containing,” including its grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0028] It should be understood that the order of the steps or the order in which certain actions are performed is not important as long as the invention remains operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0029] Furthermore, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any value inevitably contains standard deviations due to individual test methods. Therefore, unless explicitly stated otherwise, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately". Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range. Example 1

[0030] A bismaleimide epoxy glass cloth laminate and its manufacturing process include the following steps: Step 1: By mass, under a nitrogen atmosphere, 14 parts of p-chlorobenzaldehyde, 13 parts of 1,5-pentanedithiol, 2 parts of potassium carbonate, and 170 parts of N,N-dimethylformamide were added to a three-necked flask pre-equipped with a reflux condenser and a thermometer. The mixture was stirred and heated to 70°C for 8 hours. After the reaction was completed, the reaction solution was poured into deionized water, the solid was separated by filtration, washed with deionized water, and dried to obtain the long-chain precursor.

[0031] Step 2: By mass fraction, under ice-water bath conditions, add 20 parts of long-chain precursor, 14 parts of isobutyraldehyde, and the first batch of 40 parts of anhydrous ethanol to a three-necked flask pre-equipped with a reflux condenser and thermometer. Start stirring, dissolve 2 parts of potassium hydroxide in the second batch of 40 parts of anhydrous ethanol, and add it dropwise to the system. Heat to 55°C and react for 5 hours. After the reaction is complete, pour the reaction solution into deionized water to precipitate, filter to separate the solid, wash with deionized water and dry, and recrystallize with anhydrous ethanol to obtain the tetraol intermediate.

[0032] Third step: According to the mass fraction, add 25 parts of tetraol intermediate, 84 parts of phosphorus oxychloride, and 0.2 parts of aluminum chloride to a three-necked flask pre-equipped with a reflux condenser and thermometer, heat to 70°C, keep at the temperature for 6 hours, then raise the temperature to 100°C, start stirring, and react for 2 hours. After the reaction is completed, remove the solvent by rotary evaporation, wash the obtained solid with deionized water and dry it to obtain the phosphorus-based flame retardant.

[0033] Step 4: By mass fraction, under nitrogen atmosphere and ice-water bath conditions, add 12 parts of 4-maleimide-based phenol, 8 parts of triethylamine, and the first batch of 150 parts of tetrahydrofuran to a three-necked flask pre-equipped with a reflux condenser and thermometer. Start stirring. After 10 minutes, dissolve 24 parts of phosphorus-based flame retardant in the second batch of 150 parts of tetrahydrofuran and add it dropwise to the system. React at room temperature for 7 hours. After the reaction is completed, filter to remove the residue. Rotary evaporate the remaining filtrate to remove the solvent. Wash the obtained solid with deionized water and dry it to obtain the phosphorus-containing bismaleimide monomer.

[0034] Step 5: According to the mass fraction, add 60 parts of phosphorus-containing bismaleimide monomer, 70 parts of bisphenol A epoxy resin, 50 parts of tetrahydrofuran, and 18 parts of phthalic anhydride to the reaction vessel, stir and heat to 100°C, react for 2 hours. After the reaction is completed, lower the system temperature to 60°C, add 0.3 parts of 2-methylimidazole to the reaction vessel, and stir evenly to obtain bismaleimide epoxy resin prepreg. Step 6: Impregnate the alkali-free glass cloth with 35% bismaleimide epoxy resin prepreg. Then, stack five layers of bismaleimide epoxy glass cloth and place them in a hot press. The press is then heated and cured under the conditions of 6.5 MPa, 170°C and 200 min to obtain the bismaleimide epoxy glass cloth laminate.

[0035] A bismaleimide epoxy glass cloth laminate is prepared by the above preparation steps. Example 2

[0036] A bismaleimide epoxy glass cloth laminate and its manufacturing process include the following steps: Step 1: By mass, under a nitrogen atmosphere, 15 parts of p-chlorobenzaldehyde, 17 parts of 1,5-pentanedithiol, 2.7 parts of potassium carbonate, and 190 parts of N,N-dimethylformamide were added to a three-necked flask pre-equipped with a reflux condenser and a thermometer. The mixture was stirred and heated to 90°C for 10 hours. After the reaction was completed, the reaction solution was poured into deionized water, the solid was separated by filtration, washed with deionized water, and dried to obtain the long-chain precursor.

[0037] Step 2: By mass fraction, under ice-water bath conditions, add 23 parts of long-chain precursor, 16 parts of isobutyraldehyde, and 50 parts of the first batch of anhydrous ethanol to a three-necked flask pre-equipped with a reflux condenser and thermometer. Start stirring, dissolve 3 parts of potassium hydroxide in the second batch of 50 parts of anhydrous ethanol, add it dropwise to the system, heat to 60°C, and react for 7 hours. After the reaction is completed, pour the reaction solution into deionized water to precipitate, filter to separate the solid, wash with deionized water and dry, and recrystallize with anhydrous ethanol to obtain the tetraol intermediate.

[0038] Third step: According to the mass fraction, add 29 parts of tetraol intermediate, 88 parts of phosphorus oxychloride, and 0.4 parts of aluminum chloride to a three-necked flask pre-equipped with a reflux condenser and thermometer, heat to 80°C, keep at the temperature for 6 hours, then raise the temperature to 120°C, start stirring, and react for 4 hours. After the reaction is completed, remove the solvent by rotary evaporation, wash the obtained solid with deionized water and dry it to obtain the phosphorus-based flame retardant.

[0039] Step 4: By mass fraction, under nitrogen atmosphere and ice-water bath conditions, add 14 parts of 4-maleimide-based phenol, 9 parts of triethylamine, and the first batch of 160 parts of tetrahydrofuran to a three-necked flask pre-equipped with a reflux condenser and thermometer. Start stirring. After 12 minutes, dissolve 26 parts of phosphorus-based flame retardant in the second batch of 160 parts of tetrahydrofuran and add it dropwise to the system. React at room temperature for 10 hours. After the reaction is completed, filter to remove the residue. Rotary evaporate the remaining filtrate to remove the solvent. Wash the obtained solid with deionized water and dry it to obtain the phosphorus-containing bismaleimide monomer.

[0040] Step 5: According to the mass fraction, add 68 parts of phosphorus-containing bismaleimide monomer, 62 parts of bisphenol F epoxy resin, 80 parts of tetrahydrofuran, and 22 parts of 4,4'-diaminodiphenylmethane (DDM) to the reactor, stir and heat to 120°C, and react for 6 hours. After the reaction is completed, lower the system temperature to 45°C, add 0.6 parts of 2-ethyl-4-methylimidazolium to the reactor, and stir evenly to obtain bismaleimide epoxy resin prepreg.

[0041] Step 6: Impregnate the alkali-free glass cloth with bismaleimide epoxy resin prepreg. The adhesive content of the glass cloth is 40%. Stack 10 layers of the adhesive glass cloth and place them in a hot press. Hot press and cure the glass cloth under the conditions of 8 MPa pressure, 185℃ temperature and 300 min to obtain the bismaleimide epoxy glass cloth laminate.

[0042] A bismaleimide epoxy glass cloth laminate is prepared by the above preparation steps. Example 3

[0043] A bismaleimide epoxy glass cloth laminate and its manufacturing process include the following steps: Step 1: By mass, under a nitrogen atmosphere, 14.5 parts of p-chlorobenzaldehyde, 15 parts of 1,5-pentanedithiol, 2.4 parts of potassium carbonate, and 180 parts of N,N-dimethylformamide were added to a three-necked flask pre-equipped with a reflux condenser and a thermometer. Stirring was started, and the mixture was heated to 80°C and reacted for 9 hours. After the reaction was completed, the reaction solution was poured into deionized water, the solid was separated by filtration, washed with deionized water, and dried to obtain the long-chain precursor.

[0044] Step 2: By mass fraction, under ice-water bath conditions, add 22 parts of long-chain precursor, 15 parts of isobutyraldehyde, and the first batch of 45 parts of anhydrous ethanol to a three-necked flask pre-equipped with a reflux condenser and thermometer. Start stirring, dissolve 2.5 parts of potassium hydroxide in the second batch of 45 parts of anhydrous ethanol, and add it dropwise to the system. Heat to 57°C and react for 6 hours. After the reaction is complete, pour the reaction solution into deionized water to precipitate, filter to separate the solid, wash with deionized water and dry, and recrystallize with anhydrous ethanol to obtain the tetraol intermediate.

[0045] Third step: According to the mass fraction, add 27 parts of tetraol intermediate, 86 parts of phosphorus oxychloride, and 0.3 parts of aluminum chloride to a three-necked flask pre-equipped with a reflux condenser and thermometer, heat to 75°C, keep at this temperature for 6 hours, then raise the temperature to 110°C, start stirring, and react for 3 hours. After the reaction is completed, remove the solvent by rotary evaporation, wash the obtained solid with deionized water and dry it to obtain the phosphorus-based flame retardant.

[0046] Step 4: By mass fraction, under nitrogen atmosphere and ice-water bath conditions, add 13 parts of 4-maleimide-based phenol, 8.5 parts of triethylamine, and 155 parts of the first batch of tetrahydrofuran to a three-necked flask pre-equipped with a reflux condenser and thermometer. Start stirring, and after 11 minutes, dissolve 25 parts of phosphorus-based flame retardant in the second batch of 155 parts of tetrahydrofuran and add it dropwise to the system. React at room temperature for 8 hours. After the reaction is completed, filter to remove the residue, and remove the solvent from the remaining filtrate by rotary evaporation. Wash the obtained solid with deionized water and dry it to obtain the phosphorus-containing bismaleimide monomer.

[0047] Step 5: According to the mass fraction, add 65 parts of phosphorus-containing bismaleimide monomer, 65 parts of phenolic epoxy resin, 65 parts of tetrahydrofuran, and 20 parts of 4,4'-diaminodiphenyl sulfone (DDS) to the reactor, stir and heat to 110°C, and react for 4 hours. After the reaction is completed, lower the system temperature to 50°C, add 0.5 parts of 2-phenylimidazole accelerator to the reactor, and stir evenly to obtain bismaleimide epoxy resin prepreg.

[0048] Step 6: Impregnate the alkali-free glass cloth with 50% bismaleimide epoxy resin prepreg. Stack 7 layers of bismaleimide glass cloth and place them in a hot press. Hot press and cure the glass cloth under the conditions of 7 MPa pressure, 180℃ temperature and 240 min to obtain bismaleimide epoxy glass cloth laminate.

[0049] A bismaleimide epoxy glass cloth laminate is prepared by the above preparation steps.

[0050] Comparative Example 1 A bismaleimide epoxy glass cloth laminate and its manufacturing process include the following steps: Step 1: According to the mass fraction, add 25 parts pentaerythritol, 84 parts phosphorus oxychloride, and 0.2 parts aluminum chloride to a three-necked flask pre-equipped with a reflux condenser and a thermometer. Heat to 70°C and keep at that temperature for 6 hours. Then raise the temperature to 100°C and stir vigorously for 2 hours. After the reaction is completed, remove the solvent by rotary evaporation. Wash the obtained solid with deionized water and dry it to obtain the phosphorus-based flame retardant.

[0051] Step 2: By mass fraction, under nitrogen atmosphere and ice-water bath conditions, 12 parts of 4-maleimide-based phenol, 8 parts of triethylamine, and 150 parts of the first batch of tetrahydrofuran were added to a three-necked flask pre-equipped with a reflux condenser and thermometer. Stirring was started, and after 10 minutes, 24 parts of phosphorus-based flame retardant were dissolved in the second batch of 150 parts of tetrahydrofuran and added dropwise to the system. The reaction was carried out at room temperature for 7 hours. After the reaction was completed, the filter residue was removed by suction filtration, and the solvent in the remaining filtrate was removed by rotary evaporation. The obtained solid was washed with deionized water and dried to obtain phosphorus-containing bismaleimide monomer.

[0052] Step 3: According to the mass fraction, add 60 parts of phosphorus-containing bismaleimide monomer, 70 parts of bisphenol A epoxy resin, 50 parts of tetrahydrofuran, and 18 parts of phthalic anhydride to the reactor, stir and heat to 100°C, react for 2 hours. After the reaction is completed, lower the system temperature to 60°C, add 0.3 parts of 2-methylimidazole to the reactor, and stir evenly to obtain bismaleimide epoxy resin prepreg.

[0053] Step 4: Impregnate the alkali-free glass cloth with 35% bismaleimide epoxy resin prepreg. Then, stack 5 layers of bismaleimide epoxy glass cloth and place them in a hot press. The press is then heated and cured under the conditions of 6.5 MPa, 170°C and 200 min to obtain the bismaleimide epoxy glass cloth laminate.

[0054] A bismaleimide epoxy glass cloth laminate is prepared by the above preparation steps.

[0055] Comparative Example 2 A bismaleimide epoxy glass cloth laminate and its manufacturing process include the following steps: Step 1: According to the mass fraction, add 60 parts of bismaleimide monomer, 70 parts of bisphenol A epoxy resin, 50 parts of tetrahydrofuran, and 18 parts of phthalic anhydride to a reaction vessel, stir and heat to 100°C, and react for 2 hours. After the reaction is completed, lower the system temperature to 60°C, add 0.3 parts of 2-methylimidazole to the reaction vessel, and stir evenly to obtain bismaleimide epoxy resin prepreg.

[0056] The second step is to impregnate the alkali-free glass cloth in bismaleimide epoxy resin prepreg with adhesive. The adhesive content of the glass cloth is 35%. Five layers of adhesive glass cloth are stacked and placed in a hot press. The glass cloth is then hot-pressed and cured under the conditions of 6.5 MPa pressure, 170℃ temperature and 200 min time to obtain the bismaleimide epoxy glass cloth laminate.

[0057] A bismaleimide epoxy glass cloth laminate is prepared by the above preparation steps.

[0058] Experimental Example The performance of the bismaleimide epoxy glass cloth laminates obtained in Examples 1-3 and Comparative Examples 1-2 was tested. The impact strength of each component sample was tested according to GB / T 1303.10-2009, and the combustion test of each component sample was conducted according to standard UL-94. The test results are shown in Table 1.

[0059] Table 1

[0060] As can be seen from Table 1, the impact strength of the bismaleimide epoxy glass cloth laminate of the present invention in Examples 1 to 3 is much greater than that in Comparative Example 2, and the flame retardant rating is V-0 for all of them. This indicates that the bismaleimide epoxy glass cloth laminate of the present invention has good toughness and flame retardant properties. Combined with Comparative Examples 1 and 2, it can be seen that the flame retardant modification method of the present invention does not seriously affect the toughness of the bismaleimide epoxy glass cloth laminate.

[0061] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A bismaleimide epoxy glass cloth laminate and its manufacturing process, characterized in that, Includes the following steps: The first step involves a nucleophilic substitution reaction between p-chlorobenzaldehyde and 1,5-pentanedithiol to generate a long-chain precursor. The second step involves reacting the long-chain precursor with isobutyraldehyde via a cross-aldol condensation reaction to obtain a tetraol intermediate. The third step involves reacting the tetraol intermediate with phosphoric acid oxychloride to obtain a phosphorus-based flame retardant. Step 4: Phosphorylation reaction of 4-maleimide-based phenol with phosphoric flame retardant to obtain phosphorus-containing bismaleimide monomer; Step 5: Stir and heat the phosphorus-containing bismaleimide monomer, epoxy resin, tetrahydrofuran, and curing agent to react, then add an accelerator to obtain bismaleimide epoxy resin prepreg. Step 6: Impregnate the alkali-free glass cloth in bismaleimide epoxy resin prepreg, then stack and heat-press to cure and form a bismaleimide epoxy glass cloth laminate.

2. The bismaleimide epoxy glass cloth laminate and its manufacturing process according to claim 1, characterized in that, The mass ratio of p-chlorobenzaldehyde to 1,5-pentanedithiol used in the first step is 14~15:13~17.

3. The bismaleimide epoxy glass cloth laminate and its manufacturing process according to claim 1, characterized in that, The mass ratio of the long-chain precursor to isobutyraldehyde used in the second step is 20~23:14~16.

4. The bismaleimide epoxy glass cloth laminate and its manufacturing process according to claim 1, characterized in that, The mass ratio of the tetraol intermediate to phosphorus oxychloride used in the third step is 25~29:84~88.

5. The bismaleimide epoxy glass cloth laminate and its manufacturing process according to claim 1, characterized in that, The mass ratio of 4-maleimide phenol to phosphorus-based flame retardant used in the fourth step is 12~14:24~26.

6. The bismaleimide epoxy glass cloth laminate and its manufacturing process according to claim 1, characterized in that, The mass ratio of phosphorus-containing bismaleimide monomer, epoxy resin, tetrahydrofuran, curing agent, and accelerator used in step 5 is 60~68:62~70:50~80:18~22:0.3~0.

6.

7. The bismaleimide epoxy glass cloth laminate and its manufacturing process according to claim 1, characterized in that, The epoxy resin is at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and phenolic epoxy resin; the curing agent is at least one of phthalic anhydride, tung oil anhydride, 4,4'-diaminodiphenylmethane (DDM), and 4,4'-diaminodiphenyl sulfone (DDS); and the accelerator is at least one of 2-methylimidazole, 2-ethyl-4-methylimidazole, and 2-phenylimidazole.

8. The bismaleimide epoxy glass cloth laminate and its manufacturing process according to claim 1, characterized in that, The conditions for the heating reaction in the fifth step are to stir and heat to 100~120℃, react for 2~6 hours, and after the reaction is completed, lower the system temperature to 45~60℃.

9. The bismaleimide epoxy glass cloth laminate and its manufacturing process according to claim 1, characterized in that, The adhesive content of the glued glass cloth is 35-50%, preferably 40%; the hot-press curing process has a pressure of 6.5-8 MPa, a temperature of 170-185℃, and a time of 200-300 min.

10. A bismaleimide epoxy glass cloth laminate obtained by the preparation method of claim 1.

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