Heat resistant, thermally conductive anisotropic polymers - obtd. by in-situ crosslinking of mesogenic monomers in the liq. crystalline state, used in (micro)electronics esp. for multilayer circuits

摘要

Anisotropic polymers (I) are claimed. (I) are obtd. by in-situ crosslinking of mesogenic monomers of formula G-A-M-A-G in the liq. crystalline (LC) state; G = vinyl, allyl, (meth)acryloyl or epoxy; A = -(CH2)m-, -(CH2)mO- or -(CH2CH2O)n- (opt. with H partly or completely replaced by F or Cl); -(SiMe2O)n-, -OCH2-(SiMe2O)n-SiMe2-CH2-NH- or -NHCH2-(SiMe2O)n-SiMe2-CH2MH- (with m = 1-16; n = 1-10); M = -Phe-COO-X-OCO-Phe-, -Phe-OCO-X-COO-Phe-, -Cyc-COO-X-OCO-Phe- -Phe-Z-Phe, -Cyc'- or -Ar-Ar- (with Phe = 1,4-phenylene; Cyc = 1,4-cyclohexylene; X = 1,4-phenylene substd. with 1-4 gps. R R = CN, nitro, halo, acetyl, 1-8C alkyl or alkoxy, or mono- or di-(1-4C alkyl)-amino or 2-4 R gps. if R = alkyl; Cyc' = 1,4-cyclohexylene substd. with 1-4 gps. R; Ar = as for X; Z = -CH2-, -O-, -S- or -CO-). Also claimed is a process for the prodn. of (I), by spreading a thin layer of (II) on a substrate with an orienting surface, orienting the monomer and then crosslinking it in the LC state by irradiation. USE/ADVANTAGE -The invention provides heat-resistant, thermally-conductive, planarising polymers with insulating properties, for use in electronics and microelectronics, esp. in multilayer circuits; these properties of (I) prevent the electronic components becoming overheated and shortening the service life of the circuit (the thermal conductivity of (I) is up to 30 times higher than that of known insulators prepd. from soln.) Thin layers of (I) can be structured, e.g. by irradiating through a negative pattern; monomers (II) have nematic or smectic LC phases in the temp. range below 100 deg. C, and their low processing temp. enables the LC material to be oriented by drying the soln. on a treated surface (see above), without external magnetic or electric fields.