A rosin-based benzocyclobutene monomer modified epoxy resin and preparation method thereof

Abstract

The invention discloses a rosin-based benzocyclobutene monomer modified epoxy resin and a preparation method thereof. The rosin-based benzocyclobutene monomer is uniformly mixed in a liquid epoxy resin reaction system, and an epoxy curing reaction is first performed at a relatively low temperature to obtain a cross-linked network. Then, the temperature is continuously raised, and the benzocyclobutene in the rosin-based benzocyclobutene monomer is ring-opened to form a re-cross-linked network, and finally the rosin-based benzocyclobutene monomer modified epoxy resin is obtained. Compared with unmodified epoxy resin, the rosin-based benzocyclobutene monomer modified epoxy resin of the invention has a lower dielectric constant and water absorption rate, and has better mechanical properties and thermal stability.

Description

Technical Field

[0001] The invention relates to a rosin-based benzocyclobutene monomer modified epoxy resin and a preparation method thereof, belonging to the technical field of natural resource modification. Background Art

[0002] Epoxy thermosetting resin is a multifunctional commercial polymer material with a three-dimensional cross-linked structure. Due to its good comprehensive properties (electrical insulation and high thermal stability, etc.), it is widely used in various fields, such as high-frequency printed circuit boards (PCBs), carbon fiber reinforced composites (CFRCs), and aerospace. In recent years, with the development of high-frequency communications, the miniaturization of integrated circuit components has led to delays and losses in interconnected signals, which are proportional to the dielectric constant of the insulating material. Therefore, in the manufacturing process of printed circuit boards, the matrix resin as insulation and support must have a low dielectric constant (k) and water absorption. At present, due to the high polar groups such as hydroxyl, imine, and ester generated after curing, traditional epoxy resins can no longer meet the lower dielectric requirements of modern printed circuit board substrates.

[0003] Rosin modified polymer materials are widely used in surfactants, ink coatings, food industry, papermaking additives, pharmaceutical pesticides, etc., and rosin modified polymer materials will also replace the previous petrochemical raw materials, which can reduce the damage to the environment on the one hand, and slow down the current situation of oil resource depletion on the other hand. Rosin has good hydrophobicity, large volume rigid phenanthrene ring structure, and contains double bonds and carboxyl groups in the molecular structure. It can synthesize functional monomers through various reaction pathways to prepare polymer materials. In the application of polymer materials, the introduction of rosin structure can significantly improve the hardness, gloss, heat resistance and water resistance of the material.

[0004] Benzocyclobutene (BCB) resin is a new type of active resin. It can form both thermoplastic resin and thermosetting resin. Its resin has excellent thermal stability, molding processability, low dielectric constant and low thermal expansion coefficient. Benzocyclobutene can generate highly active o-quinodimethane intermediates at high temperatures, which can form products with eight-membered rings through self-coupling.

[0005] Theoretically, there are two strategies to reduce the k value of materials: one is to reduce the polarizability of the material; the other is to introduce pores or increase the free volume to reduce the density of the material. The huge rosin skeleton can increase the free volume of the material, and the re-crosslinked network of the BCB group can inhibit the polarizability of the polar group and the orientation of the polymer chain segment. Therefore, introducing the re-crosslinked network of the rosin skeleton and the BCB group into the epoxy resin can reduce the dielectric constant and water absorption of the epoxy resin, and at the same time improve the adhesion, heat resistance and mechanical properties of the resin. Summary of the invention

[0006] In order to solve the defects of epoxy resin in the prior art such as high dielectric constant and water absorption, the present invention provides a rosin-based benzocyclobutene monomer modified epoxy resin and a preparation method thereof. The prepared rosin-based benzocyclobutene monomer modified epoxy resin increases the free volume, rigidity and hydrophobicity of the resin, while reducing the polarizability of the resin, so that the resin has a lower dielectric constant and water absorption, as well as higher thermal stability and mechanical properties.

[0007] In order to solve the above technical problems, the present invention provides a rosin-based benzocyclobutene monomer modified epoxy resin, the raw materials of which include: liquid epoxy resin (E51), methylhexahydrophthalic anhydride (MHHPA), rosin-based benzocyclobutene monomer and accelerator.

[0008] Preferably, the molar ratio of epoxy groups in the liquid epoxy resin (E51) to methylhexahydrophthalic anhydride (MHHPA) is always 1:0.85-1.

[0009] Preferably, the rosin-based benzocyclobutene monomer is 12-benzocyclobutene dehydroabietic acid (BCB-DA);

[0010] Preferably, the 12-benzocyclobutene dehydroabietic acid (BCB-DA) accounts for 0-15%wt of the total mass of the liquid epoxy resin (E51) and methylhexahydrophthalic anhydride (MHHPA).

[0011] Preferably, the accelerator accounts for 0.2 wt%-2 wt% of the total curing system.

[0012] Preferably, the accelerator is at least one of N,N-dimethylbenzylamine (BDMA), 1,2-dimethylimidazole (DMI) or 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30).

[0013] The present invention also provides a method for preparing a rosin-based benzocyclobutene monomer modified epoxy resin, comprising stirring and mixing a liquid epoxy resin and methyl hexahydrophthalic anhydride, adding 0-15%wt of 12-benzocyclobutene dehydroabietic acid and 0.2%wt-2%wt of an accelerator, stirring and mixing to form a uniform system, and curing to obtain a rosin-based benzocyclobutene monomer modified epoxy resin;

[0014] The reaction process is as follows:

[0015]

[0016] Preferably, the curing process is:

[0017] After curing at 70-130°C for 2-4 hours, curing at 130-200°C for 4-6 hours, and then curing at 200-260°C for 2-4 hours, the temperature is lowered.

[0018] The technologies not mentioned in the present invention are all referred to the prior art.

[0019] (1) Compared with the unmodified epoxy resin, the rosin-based benzocyclobutene monomer-modified epoxy resin of the present invention has a lower dielectric constant and water absorption rate, and also has better thermal stability and mechanical properties.

[0020] (2) The preparation method of the rosin-based benzocyclobutene monomer modified epoxy resin of the present invention is to add the rosin-based benzocyclobutene monomer into the epoxy resin system for curing. The strategy for reducing the dielectric constant of the epoxy resin is to reduce the polarizability and increase the free volume in synergy. The obtained rosin-based benzocyclobutene monomer modified epoxy resin can be applied to the fields of electronics and microelectronics, and at the same time provides a new way for the utilization of biomass resources rosin in high-end scientific and technological fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is the curing behavior of the modified epoxy resin (a. curing of epoxy resin; b. post-curing of BCB groups);

[0022] Figure 2 are the FT-IR patterns of E51, MHHPA, BCB-DA and modified epoxy resin;

[0023] Figure 3 The dielectric properties of modified epoxy resins with different proportions (a. dielectric constant; b. dielectric loss);

[0024] Figure 4 It is the hydrophobicity diagram of modified epoxy resin with different proportions (a. contact angle; b. water absorption);

[0025] Figure 5 are the TGA graphs of PGEs with different ratios;

[0026] Figure 6 DMA graphs of modified epoxy resins with different proportions (a. storage modulus; b. loss factor). DETAILED DESCRIPTION

[0027] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0028] 12-Benzocyclobutene dehydroabietic acid (BCB-DA) (97%) was prepared in the laboratory.

[0029] DMA (dynamic thermomechanical analysis) was performed using a TADMA Q800 dynamic thermomechanical analyzer and a three-point bending method. The sample size was 50 mm × 10 mm × 2 mm, the heating rate was 3 °C / min, and the test range was –50 °C to 150 °C.

[0030] TGA (thermogravimetric analysis) nitrogen was used as the protective gas, and the heating rate was 10°C / min, from 25°C to 800°C.

[0031] The contact angle test was measured using a Drop Meter A-200 contact angle meter; the water absorption test was performed by immersing the samples in distilled water for 5 days at room temperature.

[0032] The dielectric properties were tested using an Agilent 4294A precision impedance analyzer with a frequency range of 1 MHz to 30 MHz.

[0033] Example 1

[0034] The preparation process of rosin-based benzocyclobutene monomer modified epoxy resin is as follows: 2.21g of liquid epoxy resin (E51) and 1.61g of methylhexahydrophthalic anhydride (MHHPA) are added to a three-necked flask, and 0.20g of 12-benzocyclobutene dehydroabietic acid (BCB-DA) and 0.0201g of N,N-dimethylbenzylamine (BDMA) are added under mechanical stirring to make it a uniform system; then poured into a mold, cured at 90°C for 2h, at 130°C for 2h, at 150°C for 2h, at 180°C for 3h, and finally at 250°C for 3h. Rosin-based benzocyclobutene monomer modified epoxy resin (BCB-DA-5) is obtained.

[0035] like Figure 1 As shown in the figure, the curing of rosin-based benzocyclobutene monomer-modified epoxy resin before 200°C belongs to the curing of epoxy groups with anhydride and carboxylic acid ( Figure 1 a); Curing after 200°C is a ring-opening curing of the BCB group ( Figure 1 b), while the epoxy resin without BCB-DA addition was not post-cured.

[0036] like Figure 2 As shown, the characteristic peak of epoxy in E51 is at 914 cm –1 In MHHPA, at 860cm –1 and 1774cm –1 The characteristic peak of anhydride can be observed at 1693 cm –1 and 1468cm –1 After curing, the typical epoxy peak and BCB peak in the modified epoxy resin completely disappeared, and the anhydride and carboxyl groups were completely converted to the peak at 1726 cm –1 The ester group at the bottom of the tube was found. This indicates that the modified epoxy resin was successfully prepared.

[0037] Example 2

[0038] The preparation process of rosin-based benzocyclobutene monomer modified epoxy resin is as follows: 2.21g of liquid epoxy resin (E51) and 1.61g of methylhexahydrophthalic anhydride (MHHPA) are added to a three-necked flask, and 0.42g of 12-benzocyclobutene dehydroabietic acid (BCB-DA) and 0.0424g of 1,2-dimethylimidazole (DMI) are added under mechanical stirring to make it a uniform system; then poured into a mold, cured at 80°C for 2h, cured at 120°C for 2h, cured at 150°C for 3h, cured at 180°C for 2h, and finally cured at 250°C for 2h. Rosin-based benzocyclobutene monomer modified epoxy resin (BCB-DA-10) is obtained.

[0039] Example 3

[0040] The preparation process of rosin-based benzocyclobutene monomer modified epoxy resin is as follows: 2.21g of liquid epoxy resin (E51) and 1.61g of methylhexahydrophthalic anhydride (MHHPA) are added to a three-necked flask, and 0.67g of 12-benzocyclobutene dehydroabietic acid (BCB-DA) and 0.0225g of 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30) are added under mechanical stirring to make it a uniform system; then poured into a mold, cured at 90°C for 2h, cured at 130°C for 2h, cured at 140°C for 2h, cured at 180°C for 3h, and finally cured at 250°C for 3h. Rosin-based benzocyclobutene monomer modified epoxy resin (BCB-DA-15) is obtained.

[0041] Example 4

[0042] The preparation process of rosin-based benzocyclobutene monomer modified epoxy resin is as follows: 2.21 g of liquid epoxy resin (E51) and 1.61 g of methylhexahydrophthalic anhydride (MHHPA) are added to a three-necked flask, and 0.0191 g of N,N-dimethylbenzylamine (BDMA) is added under mechanical stirring to make it a uniform system; then poured into a mold, cured at 90°C for 2 h, at 130°C for 2 h, at 150°C for 2 h, at 180°C for 3 h, and finally at 250°C for 3 h. Rosin-based benzocyclobutene monomer modified epoxy resin (BCB-DA-0) is obtained.

[0043] The dielectric properties of epoxy resin modified with rosin-based benzocyclobutene monomers in different proportions obtained in Examples 1 to 4 are as follows: Figure 3 As shown. Figure 3 It can be seen from a that the dielectric constant of the epoxy resin modified by rosin-based benzocyclobutene monomer first decreases and then increases with the increase of BCB-DA addition, and reaches the minimum at BCB-DA-10, which is 2.72; in addition, the dielectric loss of the epoxy resin modified by rosin-based benzocyclobutene monomer is less than 0.03 ( Figure 3 b).

[0044] The hydrophobicity of the rosin-based benzocyclobutene monomer modified epoxy resin obtained in Examples 1 to 4 is shown in FIG. Figure 4 As shown. Figure 4 a It can be seen that the water contact angle of the epoxy resin modified with rosin-based benzocyclobutene monomer first increases and then decreases with the increase of BCB-DA addition, reaching the maximum at BCB-DA-10; Figure 4 As shown in Figure b, the water absorption rate of the epoxy resin modified by rosin-based benzocyclobutene monomer first decreases and then increases with the addition amount of BCB-DA, reaching the minimum at BCB-DA-10, which indicates that BCB-DA-10 has the best hydrophobicity.

[0045] The thermal stability of the rosin-based benzocyclobutene monomer modified epoxy resin obtained in Examples 1 to 4 is shown in FIG. Figure 5 As shown in the figure, with the introduction of BCB-DA, the temperature at which the thermal weight loss of the rosin-based benzocyclobutene monomer-modified epoxy resin reaches 5% is significantly increased.

[0046] The DMA graphs of the rosin-based benzocyclobutene monomer-modified epoxy resins obtained in Examples 1 to 4 are as follows: Figure 6 As shown. Figure 6 a It can be seen that the storage modulus of the epoxy resin modified with rosin-based benzocyclobutene monomer increases with the increase of BCB-DA addition; Figure 6 As shown in (b), the glass transition temperature of the epoxy resin modified with rosin-based benzocyclobutene monomer also increases with the increase of BCB-DA addition.

[0047] The rosin-based benzocyclobutene monomer modified epoxy resin obtained by the present invention has a low dielectric constant and water absorption rate; at the same time, it has good glass transition temperature, thermal stability and thermal stability. Its dielectric constant and water absorption rate are respectively as low as 2.72 and 0.861%, the temperature when the thermal weight loss is 5% is higher than 360°C, the glass transition temperature and storage modulus are respectively as high as 163°C and 1.5GPa, and can be applied to the fields of electronics and microelectronics.

[0048] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a rosin-based benzocyclobutene monomer modified epoxy resin, characterized in that: The steps include: After the liquid epoxy resin and methyl hexahydrophthalic anhydride are stirred and mixed, 0-15%wt of 12-benzocyclobutene dehydroabietic acid and 0.2%wt-2%wt of N,N-dimethylbenzylamine are added, stirred and mixed into a uniform system, and then cured to obtain a rosin-based benzocyclobutene monomer modified epoxy resin; The reaction process is as follows:

2. The method for preparing a rosin-based benzocyclobutene monomer-modified epoxy resin according to claim 1, characterized in that: The molar ratio of epoxy groups to methylhexahydrophthalic anhydride in the liquid epoxy resin is always 1:0.85~1.

3. The method for preparing a rosin-based benzocyclobutene monomer-modified epoxy resin according to claim 1, characterized in that: The curing process is: After curing at 70-130°C for 2-4 hours, curing at 130-200°C for 4-6 hours, and then curing at 200-260°C for 2-4 hours, the temperature is lowered.

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