摘要:
Accelerator composition for a rubber latex derived from a conjugated diene and optionally a vinyl aromatic comonomer comprising: (i) a diisopropyl xanthogen polysulphide (DIXP), (ii) an alkyldithiocarbamate wherein the alkyl chain contains from 5 to 20 carbon atoms, and (iii) diphenylguanidine (DPG), a curable aqueous synthetic rubber latex composition comprising said accelerator composition, a process for the water-based solvent-free manufacture of synthetic shaped synthetic elastomeric articles, prepared by using said accelerator composition.
摘要:
A process for the production of green ceramic preforms for dental parts involves introducing a model into ceramic slip in a slip container for coating the model. Ceramic slip is controllably drawn off from the slip container and the coated model removed. An apparatus for producing green ceramic preforms includes an opening in the slip container through which flow of the ceramic slip is controllable. The green ceramic preform may be used to produce a dental part. Conduit means are so arranged on the slip container that ceramic slip can be controlledly drawn off out of the slip container through the conduit means.
摘要:
A method for forming an optical thin film on a substrate comprises the steps of preparing a sol solution containing minute particles for an optical element dispersed in a dispersion medium, putting the prepared sol solution in a tightly closable vessel to heat and pressurize the sol solution, and then applying the heated and pressurized sol solution onto an optical substrate. The obtained thin film has a refractive index of 1.16 with respect to a light beam having a wavelength of 193 nm, in which the transmission loss is not more than 0.5%. An optical lens including the optical thin film formed on the surface, and an exposure apparatus including the lens provided for a projection optical system or an illumination system are provided.
摘要:
A water based binder for use in a slurry for investment casting. The binder includes a mixture of a colloidal silica sol and at least one latex polymer. The latex polymer is preferably an acrylic latex or a styrene butadiene polymer (or a combination of these) which reduces the processing time between dips during shell mold making for investment casting. The latex polymer further lowers a critical concentration point or gelation point of the colloidal silica sol. The binder may be used as a primary binder or a backup binder in the shell mold making process. To make the slurry, the binder is combined with at least one refractory powder, preferably a refractory powder selected from the group of: alumino-silicates, fused silica, quartz silica, alumina, zircon, and zirconia.
摘要:
Certain polyester-based polyurethaneureas in solutions of organic solvent at a 12 to 20% concentration are particularly suited for use in a mandrel-dipping process for producing thin-walled elastic articles, such as surgical gloves, which are more resistant to puncture and tear than conventional surgical gloves made from rubber latex.
摘要:
The glove according to the present invention has, at least partially, a laminated part 2 in which a plurality of different types of rubbers are successively laminated. In the laminated part 2, the lowermost layer is a natural rubber layer, and the top surface layer is all oil-resistant rubber layer (for example, an acrylonitrile-butadiene rubber layer). The glove manufacturing method according to the present invention comprises the steps of immersing a glove mold in natural rubber latex containing a heat-sensitive coagulant to form a coating of the lowermost layer on the mold surface, and immersing at least a part of the lowermost layer in another rubber latex different from the first-mentioned rubber latex. The glove of the present invention has high strength and is economical and excellent in oil resistance and solvent resistance.
摘要:
The present invention relates to an improved process and partible mold for forming a light-weight synthetic ceramic log for use in natural gas, propane and wood-burning fireplaces and stoves which are both fully-vented and non-vented depending upon the particular design of the heat generating equipment. In the subject process, a flexible porous patterned screen is formed simulating the exterior bark portion of a tree or log having a reverse image. Such screen is designed with both porous and non-porous surface characteristics for mounting as a separate element within the partible mold. The flexible porous patterned screen is mounted within the partible mold having major interior surface areas which are capable of connection to a vacuum source for withdrawing water from a liquid composition containing ceramic fibers to rapidly form the ceramic log within the mold during short periods of vacuum molding. After vacuum extraction of the liquid components of the molding composition containing multiple ceramic fibers, the partible mold is opened and the separable screen and newly-formed log are taken therefrom and separated, following which the synthetic log is dried to increase its structural strength for further handling and processing. The molding composition contains both finely-divided ceramic fibers such as aluminosilicate fibers and a colorant such as iron chromite to produce the ceramic log having a dark colorization. After the log is formed and dried, the log is then subjected to an additional colorizing operation to give its exterior surface areas greater colorization ranging from brown to gray to black depending upon the desired surface characteristics to be obtained.
摘要:
A process for rapidly forming a laminar ceramic shell mold on a supporting structure comprising alternately, in either order, the steps of: (1) dipping the support structure into a bath comprising either an alkali stabilized solution of ionic silicate or an alkali stabilized solution of colloidal silica to define a first coating on the support structure; and (2) dipping the support structure into a bath comprising an acid stabilized solution of phosphate modified aluminum salt to define a second coating on the support structure. The coatings on the support structure react to form a gel set shell which can be fired to a ceramic material. The dipping step sequence is repeated to provide additional coatings which react to define additional layers of gel set shell. The rate of laminate thickness buildup can be increased by including fine particulate refractory in the coating baths and the coated surface can be contacted by dry, relatively coarse refractory to define a stucco layer between the dip coatings. The chemically induced gel set eliminates the need for air drying between coating applications thereby saving a major portion of the total process time. When the laminar refractory is formed around a disposable wax pattern of a desired metal shape it produces a strong ceramic shell mold that fully meets the requirements for the precision casting of metals.
摘要:
There is disclosed a process for applying a refractory filler and a hydrate of Al(H.sub.2 PO.sub.4).sub.3 or polyphosphates as a binder to a single or multi-layered carrier material to form a single or multi-layered, thin-walled structure subsequently hardened on the carrier material. The hardening is preferably conducted at a temperature below 400.degree. C. There is thus obtained a phosphate-bonded, thin-walled shaped article which is refractory at temperatures above 1300.degree. C.
摘要翻译:公开了将耐火填料和Al(H 2 PO 4)3或多磷酸盐的水合物作为粘合剂施加到单层或多层载体材料上以形成单层或多层薄壁结构的方法,随后在 载体材料。 硬化优选在低于400℃的温度下进行。因此,获得了在1300℃以上耐火材料的磷酸盐键合的薄壁形状的制品。
摘要:
A method for the production of dipped articles of rubber latices, wherein rubber latices are used which have an average rubber-particle diameter of no more than 200 nm and contain a rubber having a Defo value of less than 2000, the rubber latices having been prepared by the polymerization of a monomer mixture of 85 to 50 parts by weight of butadiene and/or isoprene, 10 to 40 parts by weight of acrylonitrile or methacrylonitrile, 0 to 40 parts by weight of styrene, 0 to 10 parts by weight of acrylamide, methacrylamide and/or their methylol derivatives and 0.1 to 10 parts by weight of an .alpha.-.beta.-unsaturated carboxylic acid, in aqueous emulsion in the presence of 0.5 to 6.0% by weight, based on monomer, of an alkylaryl sulphonate and 0 to 5% by weight, based on monomer, of one or more other surface-active substances as emulsifier, at a pH-value below 7, and wherein the pH of the latex is adjusted to a value above 8 with an alkali hydroxide on completion of polymerization and the dipped article of rubber produced by said method.