Preparation of one-component addition-cure liquid silicone rubber coating with enhanced storage stability and bond strength

Abstract

It is of great interest and challenge to simultaneously improve the storage stability and bond strength of one-component addition-cure liquid silicone rubber (OLSR) coating for electronic circuit board. In this work, we proposed an e cient approach to address this issue by incorporating both cyano-modi cation platinum catalyst (CN-PT) and urethane-containing poly(hydromethylsiloxane) (N-PHMS) into OLSR coating using a mechanical mixer. The CN-PT and N-PHMS were synthesized through thermal polymerization reaction and hydrosilylation reaction, respectively. The OLSR coating containing 0.3 phr CN-PT and 3 phr N-PHMS showed the best properties, with a tensile bond strength of 1.63 MPa, a storage period > 180 d at 25°C, and a curing rate < 2 h at 80°C. The salt-spray resistance and continuous power-on performance of OLSR coating were also improved, compared with pure OLSR coating. The synergism of CN-Pt and N-PHMS on the enhancement both the storage stability and bond strength of OLSR coating was also explored. Our ndings exhibited great potentials for fabricating OLSR coating with excellent long-term stable service performance including high storage stability and protective ability.

Synthesis of alkynyl phosphite ligands and its application in the preparation of high stability one‐component heat‐curable silicone rubber

“…Silicone rubber needs to be able to cure quickly at high temperatures and maintain considerable fluidity at room temperature so that the desired shape can be obtained during the molding process. 28 The time that the silicone rubber maintains a certain fluidity is defined as the potlife. The viscosity growth of silicone oil at 70 and 25 C is shown in Figure 6.…”

“…27 During the processing and storage of curable polysiloxanes, the room temperature activity of the Karstedt's catalyst must be inhibited. [28][29][30] It is reported that the use of several electrondonating substituent ligands, such as carbene, 31,32 organophosphine, 33,34 as well as sulfoxides, 35 can effectively control the catalytic activity of Karstedt's catalyst at room temperature. 29,36,37 Kownacki 33 synthesizes a series of triorganophosphites compounds, which are used with Karstedt's catalyst to catalyze the crosslinking reaction of polymethylvinylsiloxane.…”