摘要:
The resin comprises oligomers of naphthalic acid groups bridged by substantially only keto groups, the oligomers being joined together with a di- or tetra-functional primary aromatic amine and having been derived from a resin produced by acid-catalysed condensation of acenaphthene and a formaldehyde donor. It is envisaged that the resin will be of use in the preparation of drogue parachutes and in other circumstances where a thermally stable resin is required.
摘要:
This invention relates to a novel varnish for use in preparing glasscloth laminates which are stable at high temperatures. The varnish comprises a phenolated naphthalene formaldehyde resin having a molecular weight from 350 to 500 and a combined phenol content from 37 to 54%, a curing agent for the resin, and a lower secondary alcohol as the solvent, the varnish containing about 50% w/w of the resin. The varnish can be used to form glasscloth laminates for the production of printed circuit boards, copper clad laminates and blading for turbines.
摘要:
This invention relates to an improved poly-(amide-imide) resin, a process for its preparation and its use as a temperature resistant resin. According to the present invention, there is provided an improved method of producing a poly-(amide-imide) resin comprising the steps of;
(1) reacting a phenanthrene with formaldehyde or a formaldehyde donor in the presence of an acid catalyst to give a phenanthreneformaldehyde reaction product having substantially only methylene bridges; (2) removing from the reaction product unreacted phenanthrene; (3) treating the reaction product with formaldehyde or a formaldehyde donor in the presence of an acid catalyst to give a high molecular weight product having substantially only methylene bridges; (4) oxidising the high molecular weight product to break the 9, 10 bond in the phenanthrene moieties to produce a polycarboxylated reaction product; (5) reacting the polycarboxylated reaction product with an aromatic diamine to produce a poly-(amide-imide) resin.
The resin would find use as a lamp capping cement, as a high temperature insulator, in copper clad high temperature printed circuits, in electrical heater panels, in transformers and in glass or asbestos laminates for use as compressor blades.
摘要:
A hydrotreating catalyst which is resistant to carbonaceous deposits and is particularly useful for hydrotreating coal-derived liquids, is molybdenum or tungsten disulphide in an amount of 0.1 to 10% by weight, substantially completely on the outer surface of an active carbon support having a surface area in excess of 800 m 2 /g. The catalyst can be made by absorbing molybdenum or tungsten trisulphide onto the active carbon support and reducing the trisulphide to the disulphide.
摘要:
A three sectioned arch is set in an underground passage by mounting an arch crown section (9) in a fixture (23) and positioning the fixture on a platform (20) of a monorail transport device (16). The platform (20) is raised and lowered through a linkage mechanism (21) to position the crown section while it is fixed in position.
摘要:
Ethanol, propanol and butanol may be made in good yields by reacting a lower alcohol such as methanol with a gas containing CO and H₂ in the ratio 20:80 to 0:100 by volume H₂ to CO, recycling lower alcohol and maintaining a CO partial pressure of at least 30 bar at the reactor exit.
摘要:
Briquettes are tested to decrease efflorescence and to improve abrasion resistance and surface appearance, by dipping or spraying the formed briquettes with a solution of polyvinyl alcohol having a concentration greater than 1 part of polyvinyl alcohol to 250 parts of water.
摘要:
A breathing apparatus providing security of oxygen supply in use and with the potential for a long duration comprises personal gas supply means (10,11,12) connected to a canister, 3, containing a substance generating oxygen on reaction with carbon dioxide and moisture in a wearer's exhalations. A bottle of compressed oxygen, 6, doses oxygen into the breathing circuit when required by the wearer.