Multireactive polymerizable mesogenic compounds

A multireactive polymerizable mesogenic compound of formula I

• R1—MG—R2 I
• wherein
• R1 is halogen, CN, OCN, NCS, NO2 or an alkyl radical with 1 to 30 C atoms which may be unsubstituted, mono- or polysubstituted by halogen or CN, optionally one or more non-adjacent CH2 groups being replaced, in each case independently from one another, by —O—, —S—, —NH—, —N(CH3)—, —CO—, —COO—, —OCO—, —OCO—O—, —S—CO—, —CO—S—, —CH═CH— or —C≡C— in such a manner that oxygen atoms are not linked directly to one another, or alternatively has one of the meanings of R2 or is P—(Sp—X)n—,
• P is a polymerizable group selected from CH2═CW—COO—, WCH═CH—O—, CH2═CH-Phenyl-(O)k— and
• with W being H, CH3 or Cl and k being 0 or 1,
• Sp is a spacer group with 1 to 25 C atoms,
• X is —O—, —S—, —CO—, —COO—, —OCO—, —OCO—O—, —CO—NH—, —NH—CO—, —OCH2—, —CH2O—, —SCH2—, —CH2S—, —CH═CH—COO—, —OOC—CH═CH— or a single bond,
• n is 0 or 1,
• MG is a mesogenic group of formula II
• —(A1—Z)m—A2— II
• wherein
• Z is —O—, —S—, —CO—, —COO—, —OCO—, —CO—NH—, —NH—CO—, —CH2CH2—, —OCH2—, —CH2O—, —SCH2—, —CH2S—, —CH═CH—, —CH═CH—COO—, —OCO—CH═CH—, —C≡C— or a single bond,
• A1 and A2 are each independently 1,4-phenylene in which, in addition, one or more CH groups are optionally replaced by N;
• 1,4-cyclohexylene in which, in addition, one or two non-adjacent CH2 groups are optionally replaced by O and/or S;
• 1,4-cyclohexenylene;
• 1,4-bicyclo(2,2,2)octylene;
• piperidine-1,4-diyl;
• naphthalene-2,6-diyl;
• decahydronaphthalene-2,6-diyl;
• or 1,2,3,4-tetrahydro-naphthalene-2,6-diyl;
• all these groups optionally being unsubstituted, mono- or polysubstituted with F, Cl, OH, CN, NO2 or alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl groups having 1 to 7 C atoms wherein one or more H atoms may be substituted by F or Cl, and
• m is 1, 2 or 3, and
• R2 is alkyl with 1 to 25 C atoms which may be unsubstituted, mono- or polysubstituted by halogen or CN, optionally one or more non-adjacent CH2 groups being replaced, in each case independently from one another, by —O—, —S—, —NH—, —N(CH3)—, —CO—, —COO—, —OCO—, —OCO—O—, —S—CO—, —CO—S—, —CH═CH— or —C≡C— in such a manner that oxygen atoms are not linked directly to one another, and which is substituted with at least two identical or different groups P.