Synthesis and properties of an easy‐processable bismaleimide thermoset resin

Abstract

SYNOPSISReaction of methylenedianiline and maleic anhydride in acetone, followed by cyclodehydration in the presence of acetic anhydride and 1,4-diazabicyclo [ 2.2.2 ]octane as a catalyst, affords a mixture of compounds, Desbimid, with maleimide, isomaleimide, and acetamide groups. Dissolution of this mixture in styrene and 8-hydroxyethyl methacrylate results in clear liquid resins. The viscosity of the formulated resins ranges from 100-1700 mPas at 25°C depending on the concentration of Desbimid. These systems can be processed and cured at ambient temperatures until demoulding and postcured at temperatures up to 200 or 250°C. The flexural modulus, flexural strength, and elongation at break of a number of cured formulations are found between 3500-3800 N/mm2, 90-115 N/mm2, and 2.7-3.5%, respectively.

Advanced underfill for high thermal reliability

“…Figure 2 shows that the T i and T max of the DBMI‐added underfill were lower than that of a typical underfill (epoxy/HMPA system). Also, the T i and T max of the DBMI‐added underfill were increased by decreasing the value of R , because a highly reactive group such as the urea group (CONHCO) in DBMI was reacted at a lower temperature than the reaction temperature of an epoxy/HMPA system 7. However, the T t of the DBMI‐added underfill was increased by decreasing the value of R , which was due to the high temperature reactive group, such as BMI in DBMI, which is active at high temperature.…”

“…The DBMI was obtained after washing with a sodium bicarbonate solution to remove acetic acid in the product (mp 60–80°C). The DBMI is composed of 4,4′‐bismaleimidodiphenylmethane (BMI, about 25%), 4‐maleimido‐4′‐acetamidodiphenylmethane (about 25%), and 4‐maleimido‐4′‐isomaleimidodiphenylmethane (about 10%) 7. The 1 H‐NMR (300 MHz) spectra of DBMI in acetone‐ d 6 is shown in Figure 1.…”

“…However, it is difficult to use for the underfilling process of underfill materials at low temperature (80°C) because most thermoset imides must be heated to at least 120°C to obtain the appropriate viscosity. 7 Also, it is expected that the desbimide (DBMI)-added underfill will provide good adhesion between the PCB and an underfill because the chemical structure of DBMI closely resembles that of the BMI triazine resin used for the PCB of the raw material. 8 In this study DBMI, which has a low melting point (about 80°C), was used in the underfill materials as a hardener.…”

“…To obtain a lower thermal expansion property of the EMC at high temperature, the epoxy resin was modified by a thermoset imide such as bismaleimide (BMI, melting point of 157°C), which is one of the high heat‐resistant thermosetting materials. However, it is difficult to use for the underfilling process of underfill materials at low temperature (80°C) because most thermoset imides must be heated to at least 120°C to obtain the appropriate viscosity 7. Also, it is expected that the desbimide (DBMI)‐added underfill will provide good adhesion between the PCB and an underfill because the chemical structure of DBMI closely resembles that of the BMI triazine resin used for the PCB of the raw material 8…”

Gamma Ray Irradiation‐Initiated Copolymerization of a Binary Casting System Involving DPBMIn and Vinylpyrrolidone

“…Ever since the commercialization of BMI (Kerimid 601) by Rhone-Poulene company around 1970s, efforts aimed to overcome these drawbacks have been incessantly going on and diversifying. [2][3][4][5][6][7] Among these, one approach that provided a combined solution for these two drawbacks was the introduction of an appropriate chemical structure between reactive maleimide ring groups. In this way, the thus modified BMIs with extended chain exhibited improved solubility and lowered degree of crosslink after cure.…”