Benzoxazine modified epoxy resin as well as preparation method and application thereof

Abstract

The invention discloses benzoxazine modified epoxy resin as well as a preparation method and application thereof. The benzoxazine modified epoxy resin comprises the following components in parts by weight: 40-80 parts of benzoxazine resin, 20-60 parts of epoxy resin, 7-22 parts of a curing agent and 0-1 part of a toughening agent. The high-temperature type benzoxazine modified high-temperature type epoxy resin particularly comprises benzoxazine resin with ethynyl and / or allyl and bisphenol A type or bisphenol F type benzoxazine resin, and naphthalene type epoxy resin or bisphenol F type epoxy resin containing two or more epoxy functional groups. The high-temperature-resistant epoxy resin can be mixed for use, such as four-functionality bisphenol F epoxy resin, on the premise that the mechanical strength of the high-temperature-resistant epoxy resin is reserved, the high-temperature resistance of an epoxy resin curing system can be kept, and the dielectric constant is remarkably reduced. The curing agent further improves the mechanical properties. The preparation and curing method is simple and convenient, the raw materials are easy to obtain, and the cured material has excellent characteristics of high-temperature-resistant, high-toughness and low-dielectric materials.

Description

Technical Field

[0001] The present invention relates to the field of dielectric materials, and in particular to a benzoxazine-modified epoxy resin and a preparation method and application thereof. Background Art

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

[0003] Epoxy resin is widely used in printed circuit boards, electronic potting and structural devices due to its strong adhesion, high cohesion, mechanical strength, corrosion resistance, heat resistance and electrical insulation. Although it has achieved good application, it still has major defects in high temperature resistance and low dielectric properties. At present, the methods of additive modification to reduce the dielectric constant of epoxy resin are mainly divided into three categories: introducing a pore structure, introducing a low dielectric filler and reducing molecular polarization. These modification methods improve the dielectric properties while also affecting its mechanical properties and high temperature resistance.

[0004] Benzoxazine is a new type of thermosetting resin. Its unique six-membered heterocyclic structure gives it excellent heat resistance and dielectric properties. The heat resistance of this resin makes it potentially suitable for replacing traditional materials such as phenolic resins, polyesters, epoxy resins, cyanates and polyimides in many fields. A series of progress has been made in the research on low-dielectric modification of benzoxazine resins. These studies include the synthesis of new monomers, inorganic-organic hybridization, copolymerization with other resins, etc., aiming to reduce the dielectric constant and dielectric loss and improve the high-frequency and high-speed transmission capability of signals. For example, the dielectric constant Dk of DCPD type benzoxazine is less than 3.0, and the dielectric loss Df is less than 0.0095. These excellent dielectric properties make it particularly suitable for the field of communication copper clad laminates.

[0005] Studies on the blending system of epoxy resin and benzoxazine show that this combination can overcome some of their respective shortcomings, 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 hygroscopicity. Liu Feng et al. successfully prepared composite materials of benzoxazine and phenolic resin in 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 epoxy resin-benzoxazine resin-4,4-diaminodiphenylmethane. The results show that the epoxy resin adhesive modified with benzoxazine resin has good heat resistance and flame retardancy, and the tensile shear strength at 175°C reaches 19.4MPa (Li Shuan, Du Yu, Zhang Baoyan. Flame retardancy of epoxy resin adhesive modified with benzoxazine resin [J]. Synthetic Resins and Plastics, 2023, 40(2): 23-26). Through blending modification, the blending system of epoxy resin and benzoxazine has been significantly improved in terms of thermal stability and mechanical properties, but there is still a certain gap in some occasions with high performance requirements.

[0006] At present, many industries have put forward more urgent demands on dielectric materials in the field of high temperature, such as electronic devices with higher strength and toughness, and at the same time, they hope that they are stable at high temperatures. These demands provide new directions for the preparation of composite materials. Summary of the invention

[0007] The purpose of the present invention is to provide a high temperature resistant, high toughness, low dielectric benzoxazine modified epoxy resin and a preparation method thereof, and to prepare a high temperature resistant, high toughness thermosetting resin by designing a biphenyl or naphthyl epoxy resin-high temperature resistant benzoxazine-curing agent ternary system.

[0008] In order to achieve the above object, 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 bisphenol A type or bisphenol F type.

[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 epoxy resin, biphenyl epoxy resin and bisphenol F epoxy resin, and contains 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 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, acrylic core-shell particles, carboxyl-terminated nitrile 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 a benzoxazine-modified epoxy resin, comprising the following steps: heating and mixing a benzoxazine resin and a high-temperature epoxy resin according to a ratio until they are homogeneous, then adding a curing agent and mixing them until they are homogeneous, and curing them by stepwise heating to obtain a benzoxazine-modified epoxy resin.

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

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

[0024] 1. The present invention uses a specific type of high-temperature benzoxazine to modify a high-temperature epoxy resin, especially a benzoxazine resin having an acetylene group and / or an allyl group, and a bisphenol A type or bisphenol F type benzoxazine resin, which is mixed with a naphthalene type epoxy resin or a bisphenol F type epoxy resin containing two or more epoxy functional groups, such as a tetrafunctional bisphenol F type epoxy resin, to significantly reduce the dielectric constant while maintaining the mechanical strength and high temperature resistance of the high-temperature epoxy resin. In addition, although the addition of a curing agent to the epoxy resin-benzoxazine system will slightly reduce its high temperature resistance, the reduction is small and the mechanical strength is significantly improved, which solves the problem that it is difficult to take into account both the high temperature resistance and mechanical strength of epoxy resins when using curing agents in the traditional way. In addition, adding a certain amount of toughening agent to the benzoxazine-modified epoxy resin system can improve the toughness and low dielectric properties without significantly affecting the heat resistance of the resin matrix. The benzoxazine-epoxy resin-curing agent-toughening agent system has the advantages of comprehensive high temperature resistance, low dielectric, high mechanical strength and toughness, and is suitable for fields such as aerospace, construction and electronics that have high requirements for epoxy resin performance.

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

[0026] In order to make the above-mentioned objects, features and advantages of the invention more obvious and easy to understand, the specific embodiments of the invention are described in detail below.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0028] According to one aspect of the present invention, the present invention provides a benzoxazine-modified epoxy resin, 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-mentioned formula (I) ethynyl difunctional benzoxazine is abbreviated as ABBZ, (II) allyl bisphenol A type benzoxazine is abbreviated as ABABZ, (III) bisphenol F type benzoxazine is abbreviated as BFBZ, and (IV) bisphenol A type benzoxazine is abbreviated as 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 epoxy resin.

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

[0037]

[0038] The structure of HP4710 and 4700 epoxy resin:

[0039]

[0040] The structure of the 4032 epoxy resin:

[0041]

[0042] The structure of NC3000 epoxy resin:

[0043]

[0044] The structure of NC4000H 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), acrylic core-shell particles, silicone core-shell particles and carboxyl-terminated nitrile rubber (CTBN).

[0048] According to one aspect of the present invention, the present invention also provides a method for preparing a benzoxazine-modified epoxy resin, comprising the following steps: stirring benzoxazine and epoxy at 120°C according to a ratio, quickly stirring after adding a curing agent, 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 present invention, the present invention provides an application of a benzoxazine-modified epoxy resin, which is applied in the fields of aerospace, construction and electronics, and is suitable for printed circuit boards, electronic sealing and potting glue and structural devices.

[0050] The present invention is further described in detail by examples below, but these examples should not be considered as limiting the present invention. Main raw materials and equipment used: Unless otherwise specified, the raw materials and equipment of each embodiment and comparative example are the same; materials without specifying specific models or types are purchased from the market or commonly available common models, and are not specifically limited.

[0051] Examples 1-9

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

[0053] Table 1

[0054]

[0055] As can be seen from Table 1, benzoxazine and high-temperature epoxy resin can obtain a resin system with a Tg above 200°C, which meets the use 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 / °C) and tensile strength (MPa) were tested, as shown in Table 2.

[0058] Table 2

[0059]

[0060] From the results in Table 2, it can be seen that 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 has a tensile strength of up to 91.4 MPa while maintaining good high temperature resistance (262°C), and the dielectric properties of the system are improved.

[0061] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A benzoxazine-modified epoxy resin, characterized in that: Contains the following components in parts by weight:

2. The benzoxazine-modified epoxy resin according to claim 1, characterized in that: The benzoxazine resin has an acetylene group and / or an allyl group, and / or the benzoxazine resin is of bisphenol A type or bisphenol F type.

3. The benzoxazine-modified epoxy resin according to claim 1, characterized in that: The benzoxazine resin is selected from one or a combination of chemical formulas (I), (II), (III) and (IV).

4. The benzoxazine-modified epoxy resin according to claim 1 or 2, characterized in that: The high temperature epoxy resin is one or a combination of naphthalene epoxy resin, biphenyl epoxy resin and bisphenol F epoxy resin, and contains two or more epoxy functional groups.

5. The benzoxazine-modified epoxy resin according to claim 1 or 2, characterized in that: The high temperature epoxy resin is selected from one or a combination of compounds represented by the following chemical formulas:

6. The benzoxazine-modified epoxy resin according to claim 1 or 2, characterized in that: The curing agent is selected from one or a combination of diaminodiphenylmethane, ethylenediamine, triethylenetetramine, maleic anhydride, aliphatic anhydride and aromatic amide.

7. The benzoxazine-modified epoxy resin according to claim 1 or 2, characterized in that: The toughening agent is selected from one or a combination of acrylic core-shell particles, silicone core-shell particles, carboxyl-terminated nitrile rubber (CTBN) and polyethersulfone (PES).

8. The benzoxazine-modified epoxy resin according to claim 1 or 2, characterized in that: The high temperature epoxy resin is 30-50 parts by weight.

9. The method for preparing a benzoxazine-modified epoxy resin according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: heating and mixing benzoxazine resin and high-temperature epoxy resin according to a proportion until they are homogeneous, adding a curing agent and mixing them until they are homogeneous, and curing by increasing the temperature in stages to obtain benzoxazine-modified epoxy resin.

10. Use of the benzoxazine-modified epoxy resin obtained according to any one of claims 1 to 8 or the preparation method according to claim 9, characterized in that: Used in aerospace, construction and electronics.

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