Hercules Corporation

Brian J Swetlin

Shao-Tang Sun

Harold Jabloner

Sung G Chu

Paul J Shannon

Wayne M Gibbons

Andrew B Woodside

Anita N Chan

Samuel A Thompson, Iii

Irena Gawin

Chester R Willis

Kenneth A Mazich

Liquid crystal coupled dichroic dye compositions comprising a dichroic dye moiety coupled to one or two liquid crystal moieties by a flexible spacer group having at least four atoms linked in a linear fashion; guest-host compositions comprising such liquid crystal coupled dichroic dye compositions dissolved in liquid crystal hosts and devices comprising such guest-host compositions; and liquid crystal coupled aromatic amines useful for forming the liquid crystal coupled dichroic dyes, are disclosed.

Liquid crystal coupled dichroic dyes

Epoxy resin compositions having improved storage stability before curing and improved thermal and mechanical performance after curing comprise a mixture of a polyepoxide and a curing agent that is reactive with the polyepoxide. The epoxy resin composition is characterized by a glass transition temperature of less than 20.degree. C., measured under standard conditions, after subjecting the epoxy resin composition to a specified thermal cycle. The preferred curing agents are aromatic diamines, for example, 3,7-diaminodibenzothiophene-5,5-dioxide; 3,7-diaminophenothiazine sulfone, 3,7-diamino-N-methylphenothiazine sulfone; 2,7-diamino-9-fluorenone and 2,4,6,8-tetramethyl-3,7-diaminothioxanthene sulfone.

Epoxy resin compositions with improved storage stability

A liquid crystal polymer film or fiber comprising polymeric liquid crystals having aligned multiple oriented mesogens and a process for preparing such a polymeric liquid crystal film or fiber comprising aligning in a multi-oriented state a nematic or smectic monomeric mesophase (liquid crystal monomer) and photopolymerizing the mesophase, are disclosed. The film or fiber may be adhered to a substrate, part of a liquid crystal display cell, or a free standing polymeric film or fiber. According to a preferred process, the mesophase is aligned in a multi-oriented state using linearly polarized light.

Process of preparing compositions having multiple oriented mesogens

A process of aligning or realigning a liquid crystal medium adjacent to a substrate which process comprises (1) exposing anisotropically absorbing molecules disposed on the substrate, disposed in the liquid crystal medium or which themselves are the liquid crystal medium to linearly polarized light of a wavelength or wavelengths within the absorption band of the anisotropically absorbing molecules, wherein (a) the exposed anisotropically absorbing molecules induce alignment of the liquid crystal medium at an angle + and - .theta. with respect to the direction of the linear polarization of the incident light beam and along a surface of the liquid crystal medium, (b) the liquid crystal medium comprises liquid crystals having a molecular weight of less than 1500, and (c) the anisotropically absorbing molecules are exposed by (i) linearly polarized light transmitted through at least one mask having a pattern, (ii) a beam of linearly polarized light scanned in a pattern or (iii) patterns created by interference of coherent linearly polarized light beams, and (2) terminating exposure, whereby the liquid crystal medium aligned or realigned by the exposure step remains aligned or realigned and has two or more discrete regions having different alignments, and liquid crystal devices prepared by this process, are disclosed.

Process of aligning and realigning liquid crystal media

Damage tolerant composites comprising high strength filaments in the form of bundles or tows of continuous fiber and a tough phase separated, crosslinked epoxy resin matrix are disclosed. The crosslinked epoxy resin matrix comprises infusible particles that reside primarily between plies of the composite and critically have a median particle size between 10-75 microns. Prepregs for making the damage tolerant composites and methods of making such prepregs and the epoxy resin compositions thereof are also disclosed. The epoxy resin compositions comprise the infusible particles which become segregated as to size on a surface layer of the prepreg during the process of combining the high strength filaments of the prepreg and the resin containing the epoxy resin composition. Alternatively, the infusible particles may be disposed directly on the epoxy resin surface of the prepreg.

Damage tolerant composites containing infusible particles

A process of aligning or realigning a liquid crystal medium adjacent to a coated or uncoated substrate comprising exposing anisotropically absorbing molecules to linearly polarized light of a wavelength or wavelengths within the absorption band of the anisotropically absorbing molecules, wherein (a) the exposed anisotropically absorbing molecules induce alignment of the liquid crystal medium at an angle + and -.theta. with respect to the direction of the linear polarization of the incident light beam and along a surface of the liquid crystal medium and (b) the liquid crystal medium comprises liquid crystals having a molecular weight of less than 1500, and liquid crystal cells and devices prepared by this process, are disclosed.

Described are novel thermosetting epoxy resin compositions suitable for making cured resins, prepregs and stiff, tough thermoset composites. The thermosetting compositions comprise a polyepoxide component, an amine hardner and a specified amount of certain aromatic oligomers containing functional groups which are reactive with the polyepoxide and/or hardener under curing conditions for the composition. The cured resins have a multiphase morphology which comprises at least one glassy continuous phase and at least one glassy discontinuous phase and have a fracture toughness, K.sub.IC, of at least 1.0 MPam.sup.1/2.

Thermosetting epoxy resin compositions and thermosets therefrom

Disclosed is a stiff, tough thermoset composite, the composite comprising a crosslinked epoxy resin matrix and high strength filaments. The resin matrix comprises a glassy discontinuous phase dispersed in a glassy continuous phase that continues throughout the resin matrix. Volume fractions of the discontinuous phase are at least about 35% of the total volume of the continuous and discontinuous phases combined in exceptionally tough composites. Also disclosed are novel resin compositions suitable for making these thermosets.

Epoxy thermosets having improved toughness

Described are novel thermosetting epoxy resin compositions suitable for making cured resins, prepregs and stiff, tough thermoset composites. The thermosetting compositions comprise a polyepoxide component, an amine hardener and a specified amount of certain aromatic oligomers containing functional groups which are reactive with the polyepoxide and/or hardener under curing conditions for the composition. The cured resins have a multiphase morphology which comprises at least one glassy continuous phase and at least one glassy discontinuous phase and have a fracture toughness, K.sub.IC, of at least 1.0 MPam.sup.1/2.

Growing community of inventors

Wilmington, DE, United States of America

Brian J Swetlin