Document OEG3paz618nbOzaJakaXL1w1e

ECHA European Chemical Agency Re: Comments for Annex XV restriction report (PFAS) c`Soumpppoorutnidngs tbhyeccyoamnomecnotmspooufnJdNsC Corporation about the substitutionoffluorinated liquid crystal aLriequhiidgchrlyysstaolplhiinsetmiactaetreidamlastfeorriaalcstiwviet-hmastpreicxialliqpuriodpcerrytsiteasl. dOinseploafysth(heermeoasftteirmproerftearnrted ptrooapserAtMi-eLsCisDs) the high electrical resistivity, because other properties like the voltage holding rato depend on t. In order to obtain materials with high electrical resistivity the compounds have to be purified by special methods. But as has been shown inthe paper Mol. Cryst. Liqu. Cryst. 260, 1995 p. 13-21, there sa limitof the electrical resistivity depending on the chemical nature of the respective compound. In compounds with weak chemical bonds by inherent decompositionofthe compounds polar impurities maybe formed, which control th mit of the electrical resistivity and thus the voltage: holding ratio, Tis means further attemptsofpurification cannot futher improve the properties of the respective compounds. fItliusorwienlaltkednoliwqnuitdhcartystthaellCi-nFe bcoonmdpoius onndesaorfetheextsrtermonegleyststaavbalielaabnlde hcahvemeiecxatlraboornddisn.aTryheprreofpoerreties ike igh electrical resistivity and hgh voltage holdingratio and depending on the detailed chemical Structure high dielectric anisotropy and useful viscosity and opticalproperties. There is no other material which can compete with fluorinated liquid crystal compounds. Materials containing cyano groups have high dielectric anisotropy and reasonable viscosity and optical properties. But dinufeluteontcheeoirf erleelcattriivceally fleodwsc,heimrircaaaltistoanbiolrithyecayt.anTohecroemfporoeutnhdesitiennhdetroendteceloemcptroiscialtiroesnisutnivdietry atnhed Voltage holding ratio is much lower than those of fluorinated materials. Therefore liquid crystalline compounds with cyano groups are not appropriate for application in modern AM-ACD's pLiqruidocrhystioalfbtdihsiepaltpapylsiiacraoetiionmnpoorftfalnutoriinnmaatendycpormodpuoctusnadnisnd aLpCpDl'iscwatoiuolnds imneianndustthreiadlicsoaupnpteriaersa.ncTehoef LcrCyDs-tTaVl'lsi,nesmmaatretripahlos.neWsi,thaurteosmpoetcitvteotdihseplsahyoswanndlomwandeyteortihoerrataipopnliocfatthioensendveipreonndmienngtoannldiqiunidorder to prevent costly damageof the economy itis not reasonable to prohibit the use of fluorinated liquid crystalline materials. Halle/Saale, May 2023 Dah Pan Prof. Or. Dietrich Demus International Scientific Consulting Office Member of the German National AcademyofScience `Leopoldina'