Antistrospic polymers and method of producing them

Details Antistrospic polymers and method of producing them Antistrospic polymers and method of producing them

1995-05-08

1996-10-29

Krass, Frederick

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Mixing of two or more solid polymers; mixing of solid...

528 73, 528 51, 528 52, 528 53, 528 54, 528 55, C08G 1800, C08G 1877, C09K 1938

Patent

active

055697275

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

The invention is directed to anisotropic polymers of liquid crystalline diepoxide and liquid crystalline diisocyanate and to a process for the production of these anisotropic polymers, possibly in the presence of catalysts, additional comonomers and other conventional additives.
Reaction products of bifunctional isocyanates and epoxies are known. They are usually designated as poly(isocyanurate oxazolidinones). It is also known that cyclotrimerization of isocyanates at lower temperatures first yields isocyanurate units which react with epoxy groups to form 5-membered oxazolidinone heterocycles only at elevated temperatures.
EP-A-0 252 359 describes the conversion of4,4'-diisocyanatophenyl benzoate with 4-epoxypropoxybenzoic acid 4'-epoxypropoxyphenyl ester. The reaction product is opaque. It has no liquid crystalline phase textures and contains only crystallized reaction products. It is stated in EP-A-0 252 359 that anisotropic polymers occur by reaction of various monomers only when the reaction temperature lies within the liquid crystalline range of the educts.
Diepoxides with mesogenic properties are described in various published references. For example, it is known that mesogenic diepoxides yield polymers with optical anisotropy when converted with various reacting agents and also when homopolymerized. Japanese Patents 63-10617 (1988) and 58-206579 (1983) describe the synthesis of various triaromatic bisazomethine diglyceridyl ethers and -esters. "Synthesis, Characterization and Theory of Polymeric Networks and Gels", Ed. S. M. Ahorni, Plenum Press, New York 1992, p. 147, describes the preparation of polyepoxy networks from mesogenic diepoxides having liquid crystalline properties. The diaromatic and triaromatic diepoxides used have broad 1 c phases. Diisocyanates with liquid crystalline properties are also known (e.g., W. Mormann, M. Brahm, Polymer 43, 187 (1993)). Cyclotrimers of mesogenic, diaromatic monoisocyanates have very weakly expressed 1 c properties as compared to the monomeric educts. Normally, the liquid crystalline character is lost during the cyclotrimerization reaction.


SUMMARY OF THE INVENTION

The object of the present invention is to propose a combination of diisocyanates and diepoxides whose conversion always yields an anisotropic polymer and a process especially suited for the production of these anisotropic polymers.
According to the invention, this object is met by anisotropic polymers of diepoxide A having the formula (I) ##STR3## where Y represents O--CH.sub.2, CH.sub.2 or a C--C single bond, ##STR4## R.sub.1 to R.sub.5 represent, independently, hydrogen, halogen, a methyl, ethyl, propyl or butyl group or and hetero-nitrogen atoms or a cycloaliphatic trans-1,4-cyclohexylene group, (VII) ##STR5## where ##STR6## n is 0 or 1 and R.sub.1 to R.sub.5 are the atoms or groups indicated in formula (I), trans-1,4-cyclohexylene group.
The present invention also provides a process for the production of the anisotropic polymers of the type mentioned above, possibly in the presence of catalysts, additional comonomers and other conventional additives, which is characterized in that the liquid crystalline diepoxide A of formula (I) and the liquid crystalline diisocyanate B selected from the group formed of diisocyanates (II) to (VII) are converted at a temperature of approximately 100.degree. to 300.degree. C. in a molar ratio of approximately 2:1 to 1:4.


DETAILED DESCRIPTION OF THE INVENTION

The compounds indicated by formulas (I) to (VII) are designated as follows: trans-1,4-diisocyanatocyclohexane, methylenebis(4-isocyanatobenzene) (MDI), hexamethylene diisocyanate (HDI), HDI biuret: (bis(6-isocyanatohexylaminocarbonyl)-(6-isocyanatohexyl)amine) and tris(6-isocyanatohexyl)isocyanurate: (1,3,5-tris(6-isocyanatohexyl)-2,4,6-trioxohexahydro-1,3,5-triazine). The other monomers prepared according to the formulas mentioned above and their production are described, e.g., in W. Mormann, M. Brahm, Polymer 43, 187-194 (1993), W. Mormann, M. Brahm, Macromolecules 24,

REFERENCES:
patent: 4762901 (1988-08-01), Dhein et al.
patent: 5314983 (1994-05-01), DeMeuse et al.

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