Research On Cyanate Ester Resin Cured At Medium-temperature For Copper Clad Laminates

With the rapid development of electronic industry, electronic information processing and communication electronic products have been going to the direction of multi-functions, micro-oriented and intension, suggesting that copper clad laminates (CCLs), the key basic material of electronic components and electronic products, must meet the target of information processing and transmission with―high-frequency, high-speed‖. Hence CCLs play the role of supporting, but the transmission of signals and the enhancement of reliability on electronic products also, reflecting that the resin matrices for CCLs should possess excellent processing characteristics, high mechanical properties, good moisture resistance, low dielectric constant and loss as well as low expansion.Cyanate ester (CE) resin is a typical thermosetting resin with outstanding integrat properties including low and stable dielectric constant (ε) and loss tangent (tanδ) over wide temperature and frequency ranges, high heat-resistant and low moisture absorption. However, it needs to be cured at high temperature for a long time; moreover, the cured CE resin has poor toughness due to the presence of highly cross-linked triazine rings.The two drawbacks greatly limit the application in the field of high-frequency CCLs. In this thesis, a novel kind of hybrid catalysts (HC) consisiting of dibutyl tin dilaurate (DBTDL) and u.v. activated tricarbonyl cyclopentadienyl manganese (CpMn(CO)3) with different moral ratios were developed to catalyze the curing of CE. The catalytic effect of HC on the properties of CE was investigated. Results show that: HC has an attractive synergy effect on the curing of CE over its two separate components. In addition, cured HC/CE resins exhibit high thermal stability and outstanding dielectric properties. When the mole ratio of DBTDL and CpMn(CO)3 is 1:20, coded HC2, the gel time of CE/HC2 is only 1/20 as that of CE, the curing peak temperature in DSC curves shifts to low temperature with a gap of about 119℃; moreover the activity energy of CE/HC2 is only 1/2 as that of CE, suggesting that CE/HC2 can be cured at medium temperature. Interestingly, the glass transition temperature (Tg) of cured CE/HC2 resin is 14℃higher than neat CE resin, while dielectric and thermal properties of cured CE/HC2 resin is as the same as that of CE resin.Besides, the effect of the CpMn(CO)3 content on the properties of CE is investigated. Results show that the effect is much more obvious with the increase of CpMn(CO)3 content, when the content is 1.00wt%, the resultant CE resin has the best mechanical, dielectric and thermal properties.A novel resin system with improved toughness and low dielectric loss based on CE and epoxy modified methyl phenyl silicone (EPMPS), coded as EPMPS-n/CE, was developed in this thesis. The curing behavior and the integrate properties such as impact strength, thermal and dielectric properties as well as water absorption are systematically investigated in detail. Results show that EPMPS can not only catalyze the curing reaction of CE, but also significantly improve the toughness and moisture-resistance of cured CE resin. In case of EPMPS/CE with 15wt%EPMPS, its impact strength is 17.8kJ/m2 (about 3 times of that of pure CE resin). In addition, the water absorption and dielectric loss of the former are only about 50%, and 79% of those of pure CE resin, respectively.The calcium carbonate (CaCO₃) whiskers are introduced into CE resins to prepare CaCO₃-n/CE composites. The mechanical, thermal and dielectric properties of the composites are investigated. Results show that the addition of surface treated CaCO₃ whiskers by KH-550 (coded as CaCO₃(KH-550)) into CE resin can not only improve the flexural and impact strength as well the char yield at 600℃, but also decrease the average linear thermal expansion coefficient with the maintaining of outstanding dielectric and thermal properties of original CE resin. The composite with 16wt% CaCO₃(KH-550) has the maximum flexural and impact strengths.