BENEFITS Excellent reactivity Improved adhesion to copper Non-tacky prepregs Multi-functional, effective crosslinker High chemical resistance TARGET MARKETS Copper Clad Laminates Structural Composites Radomes Aerospace Applications ADDITIONAL INFO SDS/TDS: SMA EP400, SMA EP400S Introducing SMA EP400 Resin and EP400S Resin Solution for Improved Copper Adhesion in Copper Clad Laminate Description The new phenol functional styrene maleic anhydride resin (SMA EP400) is a low-molecular-weight copolymer that can be reacted with epoxy resins, similar to standard SMA resins, with the phenol functional group taking the place of maleic anhydride functional group. SMA EP400S is a 50% solid solution of SMA EP400 in methyl ethyl ketone solvent for improved ease of use. The sample formulation in Table 1 shows a standard copper clad laminate (CCL) or printed wiring board (PWB) formulation. The resin is SMA EP400, which was tested in place of standard SMA EF40 resin. Various ratios of the two resins were also tested. The flame retardant is tetrabromo bisphenol A resin. Epoxy 1 is brominated bisphenol A epoxy resin and Epoxy 2 is bisphenol A diglycidyl ether resin. The catalyst is 2-methyl imidazole. The SMA EP400 was tested versus the standard SMA EF40 resin. Ratios were then combined using the two resins to track influence. Table 1: Copper Clad Laminate Formulation Resin 52.66 Flame Retardant 6.73 Epoxy 1 9.40 Epoxy 2 31.08 Catalyst 0.13
SMA EP400 has a glass transition temperature (Tg) of 146 C and SMA EF40 has a Tg of 107 C. However, Figure 1 shows how increasing the amount of SMA EP400 in an SMA EF40/epoxy system, decreases the glass transition temperature. The decrease is due to the fact that the phenol functional resin contains half the number of functional groups compared to SMA EF40 and, therefore, the crosslink density is lower, resulting in a lower glass transition temperature. Figure 1: Glass Transition Temperature (DMA) Code A B C D E % SMA EF40 100 75 50 25 0 % SMA EP400 0 25 50 75 100 Figure 2 illustrates the thermal degradation of the 5 ratios studied. Shown are the temperatures at which 1-5 weight percent losses occur. It is evident that there is little difference (all within experimental error) and no negative impact to the final properties when using increasing amounts of SMA EP400. Figure 2: Thermal Degradation (Td) 2
Figure 3 illustrates the water absorption of these resins after the boards were submerged for 24 and 48 hours. A slight decrease in weight gain is observed as more SMA EP400 is used. Figure 3: Water Absorption Figure 4 illustrates the adhesion in (lbs/in 2 ) of the boards. It is clear that after 50% loading of the SMA EP400, a sharp increase in adhesion is observed. Shown are the min, mean and max measurements (averaged for 5-10 samples). Figure 4: Adhesion to Matte Side Treated Electro-deposited 0.5 oz. Copper Foil Adhesion (lbs/in 2 ) % Weight Gain Resin 100% SMA EF40 50% SMA EF40 100% SMA EP400 50% SMA EP400 Code % SMA EF40 % SMA EP400 Min Mean Max A 100 0 0.04 0.2 0.64 B 75 25 0 0.24 0.72 C 50 50 0.08 0.16 0.4 D 25 75 0.24 1.36 3.28 E 0 100 1.68 3.44 6.08 3
Figure 5 depicts the dielectric constant in percent change from the control sample (SMA EF40 + epoxy). It is important to note that all of these values lie within experimental error, so no significant difference was observed. Also plotted on the y-axis, for reference, are two commercial boards that contain SMA EF40. Figure 5: Dielectric Constant D k A-Average = 3.28 Figure 6 depicts the dielectric loss factor, measured from 1-10 Ghz, for the boards with ratios of SMA EP400 to SMA EF40 from 0-100%. Again, these values are within experimental error and therefore, no significant difference between the D f values was observed. Also, the D f values for two commercial boards that contain SMA EF40 are shown for reference. Figure 6: Dielectric Loss Factor D f A-Average = 0.01 4
Formulation Stability To check the viscosity stability of the printed wiring board resin formulations, the formulations were kept at room temperature and observed at various times as shown in Table 2. Interestingly enough the SMA EF40 containing solutions gelled within 2-4 weeks, while the 100% SMA EP400 formulation remained stable for up to 9 months. No increase in viscosity was seen. Table 2: Stability of Printed Wiring Board Resin Formulations Formulations 2-4 weeks 1 month 9 months 100% SMA EF40/epoxy thickening gel gel 75% SMA EF40/25% SMA EP400/epoxy thickening gel gel 50% SMA EF40/50% SMA EP400/epoxy thickening gel gel 25% SMA EF40/75% SMA EP400/epoxy thickening gel gel 100% SMA EP400/epoxy no change no change no change Other Suggested Uses In addition to improving the adhesion of SMA/epoxy based formulations to copper substrates, the SMA EP400 has also been tested in other coatings, adhesives and rubber formulations. The SMA EP-400 was added to a 100% solids polyurethane coating and gave significant improvement in adhesion to a modified polyolefin substrate. Also the SMA EP400 increased adhesion of a peroxide cured EPDM rubber to metal substrates. The SMA EP400 is continuing to be tested as an adhesion promoter in acrylate and epoxy based formulations as well. About Total Cray Valley Total Cray Valley is the premier global supplier of specialty chemical additives, hydrocarbon specialty chemical, and liquid and powder tackifying resins used as ingredients in adhesives, rubbers, polymers, coatings, and other materials. Total Cray Valley has pioneered the development of these advanced technologies, introducing hundreds of products that enhance the performance of products in energy, printing, packaging, construction, tire manufacture, electronics, and other demanding applications. For more information, please visit www.crayvalley.com Total Cray Valley 665 Stockton Drive, Suite 100 Exton, PA 19341, USA 1.877.US1-CRAY *The listed properties are illustrative only, and not product specifications. Total Cray Valley disclaims any liability in connection with the use of the information, and does not warrant against infringement by reason of the use of its products in combination with other materials or in any process. CV1243.11.16 5