New grades of liquid crystal polymer (LCP) that offer improved blister resistance for electronic connectors have been introduced by the Polyplastics Group (Farmington Hills, MI). The two Laperos LCP grades, currently in a pre-commercialization phase, have been confirmed to inhibit blistering more effectively than existing materials, according to the company. Polyplastics has conducted experimental studies on different forms of blistering and is working to achieve an even greater reduction in blistering defects.
|With materials that do not easily form blisters, resin fills the cavity according to its shape, even in the part where the flow expands due to the step. Image courtesy Polyplastics.|
LCP is widely used in surface mount technology (SMT) because of its heat resistance and flowability. Blistering is a common flaw when using LCP, taking the form of bulges that appear on the surface of molded articles. Blistering has a variety of potential causes including gases released by LCP decomposition, gases that get entrapped during molding, and separation between the skin and core layers, explained the company.
Polyplastics, whose product portfolio also includes POM, PBT, PPS, GF-PET and COC, noted that it is important to use heat-stable materials that generate little gas. Laperos LCPs come in a range of grades to accommodate customer needs, including ultra-high-heat-resistant grades.
The company also conducted studies on nozzle and sprue optimization with the aim of offering solutions to blistering. Other factors such as molding conditions and mold shape design also have a strong influence on blistering.
In addition to flowability and dimensional accuracy, LCP exhibits high heat resistance and is widely used in connector applications in devices such as smartphones, which are becoming more compact and trending toward SMT. The automotive, home electronics and office automation industries have increasingly implemented LCP in recent years due to demand for dimensional accuracy and heat resistance.