Abstract: A soft, flexible, microporous film is provided having high tensile strength and good air and water vapor transmission rates therethrough while being substantially impenetrable to liquid water. This film is prepared by stretching a casting of a composition of a polyolefin and high levels of CaCO.sub.3 or glass beads and calcium stearate in two directions from 1.5-7 times in each direction to produce a film having a Gurley porosity of from 0.1 to 85 seconds. This film is especially useful for disposable items such as feminine panty liners, diapers, bed sheets, and hospital gowns. When glass beads are substituted for the CaCO.sub.3, the film is useful for battery separators.
Abstract: A method of making an elastomer lined vessel or portion of such vessel is disclosed. The method comprises causing a thin, tacky ribbon comprising an elastomer (preferably curable) to continuously so encircle a center rotational axis of a mandrel as to adjacently position and tack together integral segments of the ribbon substantially circumferentially relative to this center rotational axis thereby forming a layer of the elastomer about the mandrel which may be the shell of the vessel in case of internal application of the insulator or may be a workpiece around which the shell is built over the so-laid ribbon.
Abstract: A rotary printing press is used for printing standard pages and for double truck printing of the centerfold page. This is accomplished by mounting side by side printing plates to locking devices in the rotary printing press. The printing plates are positioned by two registrations which are selectively movable toward and away from each other to one of at least two predetermined fixed positions. In one of the fixed positions, the standard printing takes place, and in the other fixed position, the printing press is used for double truck printing.
Abstract: A cross-linked copolymer containing repeating units derived from a mixture comprising the following monomers: ##STR1## and occasionally other repeating units derived from other metathesis polymerizable cyclic compounds such as dicyclopentadiene, a process for producing the copolymer, a process for producing a molded article from the copolymer and a polymerizable composition therefor.
Abstract: Polyacrylonitrile (PAN)-based carbon fiber in the form of a filament bundle has a high Modulus and a high Tensile Strength in the Impregnated Strand Test respectively between about 42 million and 50 million psi and between about 600,000 and 900,000 psi, and Short Beam Shear Strength between about 15,000 and 19,000 psi in the Laminate Test; this PAN-based carbon fiber also has an electrolytically treated surface at 0.5 columbs per inch per approximate 12,000 filaments. The preparation of this PAN-based carbon fiber was accomplished by stretching during carbonization previously stretched and stabilized fine denier precursor while maintaining temperatures and heat up rates within certain ranges.
Abstract: A warp resistant tile and method for preparation thereof in which a primary facing layer is secured to a tile backing layer which comprises a laminate having(A) a characterizing layer of predetermined weight, bulk, and strength, this layer and being complementary to the primary facing, and to(B) a thin flexible base layer.
Abstract: Polysilazane addition polymers are prepared by (1) reacting ammonia with one or more halogenated organic silicon compounds to produce a cyclic silazane ammonolysis product and (2) reacting the ammonolysis product with from 0.1% to 30% by weight of an isocyanate, isothiocyanate, ketene, thioketene, carbodiimide, or carbon disulfide. Polysilazane addition polymers containing alkenyl or alkynyl groups can be cured by supplying energy to generate free radicals. The cured or uncured polymers can be pyrolyzed to produce silicon nitride-containing ceramic materials.
Abstract: 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 made from a rubber polymer 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.
Abstract: Disclosed is an aqueous acrylic polymer dispersion containing no protective colloid and a dispersed phase comprised of a polymer of (a) one or more monomers selected from the group consisting of acrylic or methacrylic esters containing up to 22 carbon atoms and (b) 0.1% to 2%, by weight of the total monomers, of at least one water-soluble free-radically polymerizable monomer selected from the group consisting of linear or cyclic, nonaromatic sulfonic acids or sulfonic acid metal salts, amine salts, ammonium salts and quaternary ammonium salts having (i) 4 to 36 carbon atoms, (ii) conjugated unsaturation and (iii) a solubility of at least 0.4 gram per 100 ml of water at about 20.degree. C. Also disclosed is a process for preparing the aqueous acrylic polymer dispersion by the aqueous emulsion polymerization, in the absence of a protective colloid and in the presence of a polymerization initiator, of (a) the acrylic or methacrylic ester monomer(s) and (b) the free-radically polymerizable monomer(s).
Abstract: The invention provides an inexpensive synthesis process for preparation of diethynylbenzene monomers that are useful in the preparation of polyacetylenes. This process provides for the preparation of thermally sensitive monomers in a one-pot reaction using readily available materials at low temperatures in an environment capable of absorbing large amounts of energy. Divinylbenzene is first brominated and then dehydrobrominated with sodium hydroxide or potassium hydroxide preferably in the presence of a phase transfer agent followed by distillation to recover the diethylnylbenzene product.
Abstract: Acrylate copolymers comprising (a) repeating units derived from at least one acrylic or methacrylic ester and, by weight of the total copolymer, (b) about 0.1 to 3% of repeating units derived from at least one water-soluble monomer possessing conjugated unsaturation and (c) about 0.1 to 3% of repeating units derived from at least one water-soluble allyl monomer; aqueous polyacrylate dispersions comprising such polymers; and a process of preparing the same. Optionally, the copolymers contain other free-radical polymerizable monomers.
Abstract: A cross-linked copolymer containing repeating units derived from dicyclopentadiene and metathesis polymerizable halogen-containing cycloalkenes, a process for producing the copolymer, a process for producing a molded article from the copolymer and a polymerizable composition therefor.
Abstract: Disclosed are electrorheological (ER) fluids which display improved stability against sedimentation, reduced current density and good ER responses. Thes=e ER fluids are prepared from monomers which are polymerized by dispersion polymerization in a low conductivity medium which also serves as the dispersion medium for the fluid. The ER fluids are further processed by modifying the polymer particles through polymerization of a hydrophilic monomer to form a hydrophilic shell or globule around the particles followed by neutralization through addition of an organic soluble base. The resulting dispersion is then doped with water to obtain a stable ER fluid. The hydrophilic shell or globule constitutes about 15% of the particle. Water dopant is only absorbed by the hydrophilic portion of the particle and does not enter into the core of the particle. The quantity of water is significantly reduced, which in turn results in a significant reduction of the current density at any given comparative voltage.
Abstract: Disclosed are electrorheological (ER) fluids which display improved stability against sedimentation, reduced current density and good electrorheological response. These ER fluids are prepared from monomers which are polymerized by dispersion polymerization in a low conductivity medium which in most embodiments of the invention serves as the dispersion medium for the fluid. the ER fluids are further processed by modifying the polymer particles through polymerization of a hydrophilic monomer to form a hydrophilic shell or globule around the particles. The resulting dispersion is then doped with water to obtain a stable ER fluid. The hydrophilic shell or globule constitutes a minor part of the particle. Water dopant is only absorbed by the hydrophilic portion of the particle and does not enter into the core of the particle. The quantity of water is significantly reduced, which in turn results in a significant reduction of the current density at any given applied field strength.
Abstract: This invention is a process for preparing a polymer which comprises contacting pure dicyclopentadiene with a pure tungsten catalyst complex, such as WCl.sub.3 (2,6-diisopropylphenoxy).sub.3, when tributyl tin hydride or triphenyl tin hydride is used as the activator for the polymerization. This process affords a method of polymerization of dicyclopentadiene in which the mixture gels slowly without the use of a rate moderator at 80.degree. C. (in from about 15 seconds to as much as two minutes or more) and furthermore cures quite slowly (in about 3-6 minutes). This delay makes these compositions particularly applicable to reaction injection molding processes. Moreover, both the tungsten complexes and the tin activator compounds employed in this invention are relatively insensitive to oxygen and water.
Abstract: 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.
Type:
Grant
Filed:
March 8, 1989
Date of Patent:
December 4, 1990
Assignee:
Hercules Incorporated
Inventors:
Wayne M. Gibbons, Shao-Tang Sun, Brian J. Swetlin