A benzoxazine-modified epoxy resin, and a preparation method and application thereof

Abstract

This invention discloses a benzoxazine-modified epoxy resin, its preparation method, and its applications. The benzoxazine-modified epoxy resin comprises the following components by weight: 40-80 parts benzoxazine resin, 20-60 parts epoxy resin, 7-22 parts curing agent, and 0-1 parts toughening agent. The high-temperature benzoxazine-modified high-temperature epoxy resin, especially benzoxazine resins containing acetylene and / or allyl groups, and bisphenol A or bisphenol F type benzoxazine resins, can be mixed with naphthalene-type epoxy resins or bisphenol F type epoxy resins containing two or more epoxy functional groups, such as tetrafunctional bisphenol F type epoxy resins. This method maintains the high-temperature resistance of the epoxy resin curing system while preserving the mechanical strength of the high-temperature epoxy resin, and significantly reduces the dielectric constant. The curing agent further enhances its mechanical properties. The preparation and curing methods of this invention are simple, the raw materials are readily available, and the cured material exhibits excellent characteristics of a high-temperature resistant, high-toughness, and low-dielectric material.

Description

Technical Field

[0001] This invention relates to the field of dielectric materials, and more specifically, to a benzoxazine-modified epoxy resin, its preparation method, and its application. Background Technology

[0002] Materials with low dielectric constants can effectively reduce leakage current in integrated circuits and decrease capacitance between wires, thereby reducing heat generation in integrated circuits. They are widely used in aerospace, construction, electronics, and other fields. Traditional low dielectric materials, such as polystyrene, fluorinated polymers, and liquid crystal polymers, cannot meet the requirements of some high-end applications due to their poor high-temperature resistance and low toughness.

[0003] Epoxy resins are widely used in printed circuit boards, electronic encapsulation, and structural components due to their strong adhesion, high cohesiveness, mechanical strength, corrosion resistance, heat resistance, and electrical insulation. While they have achieved considerable success, significant shortcomings remain in high-temperature resistance and low-dielectric properties. Currently, methods for modifying epoxy resins to reduce their dielectric constant mainly fall into three categories: introducing porous structures, introducing low-dielectric fillers, and reducing molecular polarization. These modification methods, while improving dielectric properties, also affect their mechanical properties and high-temperature resistance.

[0004] Benzoxazine is a novel thermosetting resin whose unique six-membered heterocyclic structure endows it with excellent heat resistance and dielectric properties. Its heat resistance makes it a potential replacement for traditional phenolic resins, polyesters, epoxy resins, cyanate esters, and polyimides in many fields. Significant progress has been made in the research of low-dielectric modification of benzoxazine resins. These studies include the synthesis of new monomers, inorganic-organic hybridization, and copolymerization with other resins, aiming to reduce the dielectric constant and dielectric loss, and improve the high-frequency and high-speed propagation capabilities of signals. For example, DCPD-type benzoxazine has a dielectric constant Dk < 3.0 and a dielectric loss Df < 0.0095; these excellent dielectric properties make it particularly suitable for copper-clad laminates used in communications.

[0005] Studies on the blending system of epoxy resin and benzoxazine show that this combination can overcome some of the shortcomings of each, such as the high curing temperature and long curing time of benzoxazine, while maintaining excellent comprehensive properties such as heat resistance, dielectric properties, dimensional stability and low moisture absorption. Liu Feng et al. successfully prepared composite materials of benzoxazine and phenolic resin with different proportions, and their tensile strength and flexural strength were better than those of pure benzoxazine resin (Liu Feng, Zhao Xina, Chen Yihua. Properties of phenolic modified benzoxazine resin and its composite materials [J]. Journal of Composite Materials, 2008, 25(5): 57-63). Li Shuan et al. prepared a ternary curing system of bisphenol A type epoxy resin-benzoxazine resin-4,4-diaminodiphenylmethane. The results showed that the epoxy resin adhesive modified with benzoxazine resin had good heat resistance and flame retardant properties, and the tensile shear strength at 175℃ reached 19.4 MPa (Li Shuan, Du Yu, Zhang Baoyan. Flame retardant properties of epoxy resin adhesive modified with benzoxazine resin [J]. Synthetic Resins and Plastics, 2023, 40(2): 23-26). Through blending modification, the blend system of epoxy resin and benzoxazine was significantly improved in terms of thermal stability and mechanical properties, but there is still a certain gap for some applications with high performance requirements.

[0006] Currently, many industries have raised more urgent demands for dielectric materials in high-temperature applications. For example, electronic devices require high strength and toughness, while also demanding stability at high temperatures. These demands have provided new directions for the preparation of composite materials. Summary of the Invention

[0007] The purpose of this invention is to provide a high-temperature resistant, high-toughness, and low-dielectric benzoxazine-modified epoxy resin and its preparation method. A thermosetting resin with high temperature resistance and high toughness is prepared by designing a ternary system of biphenyl or naphthyl epoxy resin-high-temperature resistant benzoxazine-curing agent.

[0008] To achieve the above objectives, in a first aspect, the present invention provides a benzoxazine-modified epoxy resin comprising the following components in parts by weight:

[0009]

[0010] Optionally, the benzoxazine resin has an acetylene group and / or an allyl group, and / or the benzoxazine resin is of type A or type F of bisphenol.

[0011] Optionally, the benzoxazine resin is selected from one or a combination of chemical formulas (I), (II), (III) and (IV).

[0012]

[0013]

[0014] Optionally, the high-temperature epoxy resin is one or a combination of naphthalene-type epoxy resin, biphenyl-type epoxy resin, and bisphenol F-type epoxy resin, containing two or more epoxy functional groups.

[0015] Optionally, the high-temperature epoxy resin is selected from one or a combination of compounds represented by the following chemical structural formulas:

[0016]

[0017]

[0018] Optionally, the curing agent is selected from one or a combination of diaminodiphenylmethane, ethylenediamine, triethylenetetramine, maleic anhydride, aliphatic anhydride and aromatic amide.

[0019] Optionally, the toughening agent is selected from one or a combination of silicone core-shell particles, acrylate core-shell particles, carboxyl-terminated nitrile butadiene rubber (CTBN), and polyethersulfone (PES).

[0020] Optionally, the high-temperature epoxy resin is 30-50 parts by weight.

[0021] In a second aspect, the present invention provides a method for preparing benzoxazine-modified epoxy resin, comprising the following steps: heating and mixing benzoxazine resin and high-temperature epoxy resin according to a ratio until homogeneous, then adding a curing agent and mixing until homogeneous, and then curing by staged heating to obtain benzoxazine-modified epoxy resin.

[0022] In a third aspect, the present invention provides an application of benzoxazine-modified epoxy resin in the fields of aerospace, construction and electronics.

[0023] The technical effects of this invention are as follows:

[0024] 1. This invention uses a specific type of high-temperature benzoxazine-modified high-temperature epoxy resin, especially benzoxazine resins with acetylene and / or allyl groups, as well as bisphenol A or bisphenol F type benzoxazine resins, mixed with naphthalene type epoxy resins or bisphenol F type epoxy resins containing two or more epoxy functional groups, such as tetrafunctional bisphenol F type epoxy resins, etc., to significantly reduce the dielectric constant while maintaining the mechanical strength and high-temperature resistance of the high-temperature epoxy resin. Furthermore, the addition of a curing agent to this epoxy resin-benzoxazine system, while slightly reducing its high-temperature resistance, does not significantly decrease its mechanical strength. This solves the problem that traditionally, the use of curing agents cannot simultaneously achieve both high-temperature resistance and mechanical strength in epoxy resins. In addition, the addition of a certain amount of toughening agent to the benzoxazine-modified epoxy resin system can improve toughness and low dielectric properties without significantly affecting the heat resistance of the resin matrix. The benzoxazine-epoxy resin-curing agent-toughening agent system achieves comprehensive advantages such as high-temperature resistance, low dielectric properties, high mechanical strength, and toughness, making it suitable for fields such as aerospace, construction, and electronics where high epoxy resin performance is required.

[0025] 2. The benzoxazine-epoxy resin-curing agent-toughening agent system obtained by the present invention not only retains the excellent properties of each component, but also has good processing performance. Detailed Implementation

[0026] To make the above-mentioned objects, features and advantages of the invention more apparent and understandable, the specific embodiments of the invention are described in detail below.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0028] According to one aspect of the present invention, a benzoxazine-modified epoxy resin is provided, comprising the following components in parts by weight:

[0029]

[0030] In one embodiment of the present invention, the high-temperature epoxy resin is 30-50 parts by weight.

[0031] In one embodiment of the present invention, the benzoxazine resin is one or a combination of chemical formulas (I), (II), (III) and (IV).

[0032]

[0033]

[0034] The above formulas are: (I) acetylene-based bifunctional benzoxazine (ABBZ), (II) allyl bisphenol A type benzoxazine (ABABZ), (III) bisphenol F type benzoxazine (BFBZ), and (IV) bisphenol A type benzoxazine (BABZ).

[0035] In one embodiment of the present invention, the epoxy resin is selected from one or a combination of AG80 epoxy resin, 4700 epoxy resin, 4032 epoxy resin and HP4710 type epoxy resin.

[0036] The structure of the AG80 (tetraglycidylamine type epoxy resin) epoxy resin:

[0037]

[0038] The structures of the HP4710 and 4700 epoxy resins are as follows:

[0039]

[0040] The structure of the 4032 epoxy resin:

[0041]

[0042] The structure of NC3000 epoxy resin:

[0043]

[0044] The structure of NC4000H type epoxy resin:

[0045]

[0046] In one embodiment of the present invention, the curing agent is selected from one or a combination of diaminodiphenylmethane (DDM), ethylenediamine, triethylenetetramine, maleic anhydride, aliphatic anhydride and aromatic amide.

[0047] In one embodiment of the present invention, the toughening agent is selected from one or a combination of polyethersulfone (PES), acrylate core-shell particles, silicone core-shell particles, and carboxyl-terminated nitrile butadiene rubber (CTBN).

[0048] According to one aspect of the present invention, the present invention also provides a method for preparing benzoxazine-modified epoxy resin, comprising the following steps: mixing benzoxazine and epoxy resin at 120°C according to the ratio, adding a curing agent and then rapidly mixing until uniform, and curing according to a three-stage heating process: 150°C / 2h + 190°C / 2h + 215°C / 2h.

[0049] According to another aspect of the invention, the present invention provides an application of benzoxazine-modified epoxy resin in the fields of aerospace, construction and electronics, suitable for printed circuit boards, electronic encapsulation and structural devices.

[0050] The present invention is further described in detail below through embodiments, but these embodiments should not be considered as limitations on the present invention. Main raw materials and equipment used: Unless otherwise specified, the raw materials and equipment used in each embodiment and comparative example are the same; materials not specified as specific models or types are derived from common, same models that are available through market purchases or ordinary means, and no specific limitations are imposed.

[0051] Examples 1-9

[0052] Examples 1-9 tested the glass transition temperature (Tg / ℃) and tensile strength (MPa) of different benzoxazine / epoxy resin systems, as shown in Table 1.

[0053] Table 1

[0054]

[0055] As can be seen from Table 1, benzoxazine and high-temperature epoxy resins can produce resin systems with a Tg of over 200℃, meeting the application requirements. In particular, ABBZ and ABABZ can significantly increase the glass transition temperature of various high-temperature epoxy resin systems.

[0056] Examples 10-18 and Comparative Example 1

[0057] Examples 10-18 prepared different benzoxazine-epoxy resin-curing agent systems, and Comparative Example 1 prepared an epoxy resin-curing agent system. The glass transition temperature (Tg / ℃) and tensile strength (MPa) were tested, as shown in Table 2.

[0058] Table 2

[0059]

[0060] As can be seen from the results in Table 2, the ABABZ / 4700, ABBZ / 4700, and ABBZ / 4710 systems have good high-temperature resistance. Compared with the 4032 / DDM system, the ABBZ / 4032 / DDM system can achieve a tensile strength of 91.4 MPa while maintaining good high-temperature resistance (262℃), and the dielectric properties of the system are improved.

[0061] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A benzoxazine-modified epoxy resin characterized by, It consists of the following components in parts by weight: 50 parts by weight of benzoxazine resin 37 parts by weight of high-temperature epoxy resin 13 parts by weight of curing agent; The benzoxazine resin is selected from chemical formula (I): （I）； The high-temperature epoxy resin is selected from compounds represented by the following chemical structural formulas: ； The curing agent is selected from diaminodiphenylmethane.

2. The method for preparing benzoxazine-modified epoxy resin according to claim 1, characterized in that, The process includes the following steps: heating and mixing benzoxazine resin and high-temperature epoxy resin according to the specified ratio until homogeneous, then adding curing agent and mixing until homogeneous, followed by staged heating and curing to obtain benzoxazine modified epoxy resin.

3. The application of the benzoxazine-modified epoxy resin according to claim 1, characterized in that, It is used in aerospace, construction and electronics fields.

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