Tighter Specifications on Linqstat Volume Conductive Plastic

In a pre­vi­ous arti­cle LINQSTAT: Vol­ume Resis­tiv­i­ty vs. Vol­ume Con­duc­tiv­i­ty vs. Sur­face Resis­tiv­i­ty where we describe the dif­fer­ences between Vol­ume Resis­tiv­i­ty and Sur­face Resis­tiv­i­ty, we also raise the ques­tion, “Why does CAPLINQ give “less than” val­ues (ie. <200,000 ohms per square-cm) instead of Typ­i­cal Val­ues?”

Giv­en the wide spec­i­fi­ca­tion range of LINQSTAT VCF low-lev­el vol­ume con­duc­tive film, some old­er prod­ucts could have fall­en into the MVCF or Medi­um-Lev­el vol­ume con­duc­tive film range.

So why are “less than” values given for surface resistivity of conductive plastics?

The answer that was pre­vi­ous­ly giv­en refers to the nature of the prod­uct itself. LINQSTAT Vol­ume Con­duc­tive Film is a car­bon-loaded poly­eth­yl­ene. As such, there are nec­es­sar­i­ly some dif­fer­ences in the con­duc­tiv­i­ty over the entire sur­face and the data that CAPLINQ pro­vides is meant to be a min­i­mum, repeat­able val­ue that can be used in the design of the final prod­uct.

How­ev­er, this is not the full answer, which is what I want to explain in more detail here. Both LINQSTAT VCF-Series prod­ucts and LINQSTAT MVCF-Series prod­ucts are car­bon-filled con­duc­tive plas­tics that both use the same base plas­tic and both use con­duc­tive filler. The VCF-Series prod­ucts are typ­i­cal­ly list­ed as hav­ing an sur­face resis­tiv­i­ty of <200,000 ohms/square. This is due to the process that is used to blow the plas­tic, that the dis­per­sion of the car­bon can be quite wide. In some batch­es, the con­duc­tiv­i­ty could be as high as 200,000 ohms/square but in oth­ers, it could be as low as 35,000 ohms/square. In the case of the 35,000 ohms per square, this prod­uct actu­al­ly falls with­in spec­i­fi­ca­tion of the MVCF-Series prod­ucts. We are now mov­ing away from this process to be able to give more con­sis­tent batch-to-batch results.

Can tighter specifications be given for the LINQSTAT conductive plastics?

The answer is yes. The MCVF-Series and XVCF-Series prod­ucts, use this new process. For these prod­ucts, anoth­er process is used that can dras­ti­cal­ly improve batch-to batch con­sis­ten­cy. Though we do still have stock and con­tin­ue to man­u­fac­ture some of the old VCF-Series mate­ri­als, we are slow­ly plan­ning to phase out this process in favor of the new one. This process is slight­ly (about 15%) more expen­sive, but like you our oth­er cus­tomers need to have more con­sis­tent lot-to-lot deliv­er­ies.

Which series of LINQSTAT conductive plastic films does this affect?

This affects only the VCF-Series prod­ucts. The MVCF-Series and the XVCF-Series prod­ucts all use the new process and the exist­ing VCF-Series will grad­u­al­ly change to an LVCF-Series (for low-lev­el con­duc­tive films) once the process is intro­duced for these prod­ucts too.

How can I be sure what the specification or tolerance of the LINQSTAT material is?

First, you can check the tech­ni­cal datasheet to see what is called out, and then you can ask for the Cer­tifi­cate of Analy­sis (CoA) of the request­ed prod­uct. For exam­ple, here are the spec­i­fi­ca­tions for LINQSTAT con­duc­tive plas­tic. As you can see on this cer­tifi­cate, the sur­face resis­tiv­i­ty val­ues are with­in spec­i­fi­ca­tion, but do not have the low­er-lev­el con­duc­tiv­i­ty we would expect.

Vis­it caplinq.com to learn more about con­duc­tive mate­ri­als includ­ing our broad range of elec­tri­cal­ly con­duc­tive plas­tics and anti­sta­t­ic tapes and films. If you have any ques­tions, please don’t hes­i­tate to con­tact us if you have fur­ther ques­tions on the spec­i­fi­ca­tions of elec­tri­cal­ly con­duc­tive plas­tic.

About Chris Perabo

Chris is an energetic and enthusiastic engineer and entrepreneur. He is always interested in taking highly technical subjects and distilling these to their essence so that even the layman can understand. He loves to get into the technical details of an issue and then understand how it can be useful for specific customers and applications. Chris is currently the Director of Business Development at CAPLINQ.

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