Abstract: New aromatic compounds containing at least one cyanate ester and at least one propargyl ether group, each independently directly attached to a ring carbon atom(s), are useful in the preparation of resins having a low dielectric constant.

Abstract: A polymaleimide/epoxy blend is cured with cyanamide to provide interlocked one-phase networks with superior thermal properties.

Abstract: An epoxy resin composition containing an imidazole curing agent is useful in processes for lining the interior surfaces of buried pipes. The imidazole is non-substituted at the 1 position and is preferably alkyl-substituted at the 2 position, such as 2-propyl imidazole. Pipe-lining compositions using such imidazole-cured systems have long working lives, short cure times at moderate temperatures, low tendency to exotherm, insensitivity to moisture, and low creep and shrinkage, resulting in a pipe-lining system which can be used in a wide range of field conditions and produces a superior pipe liner.

Abstract: A corner bracket 20, 120 forming part of a system of corner brackets adapted for mechanically inter-connecting in an air tight manner generally rectangular duct portions 37, 38. A first bracket 12 on the end of a first duct 37 is placed in adjacent, abutting, back to back relationship with a second bracket 6 on a second duct 38 and similarly at all four corners of the duct ends. Tabs 27, 127 which are formed from the corner bracket 20, 120 are located so as to be foldable over the adjacent, back to back brackets so as to mechanically bind the brackets together. The folding operation can be performed with hand tools such as hammers and the like. Using appropriate seals, an air tight, mechanically sound duct joint is accomplished. The brackets and the bracket inter-connection system are particularly suited for use with air conditioning duct networks.

Abstract: A locking clip (1) for air conditioning ducting or the like where the ducting (13, 14) is of the type which has flanges (11, 12) protruding upwardly and generally at right angles from the ends of the ducting. The clip 1 is adapted to clamp the outer faces of the flanges (11, 12) at the same time, resist sliding of the clip (1) along the mated flanges (11, 12) by the action of central tabs (5, 6) protruding from the spine (4) of the clip (1) between the inside, mating faces of the flanges (11, 12). In one form serrations on the ribs (5, 6) help to maintain frictional engagement between the ribs (5, 6) and the inside faces of the flanges (11, 12).The locking clip (1) is particularly suited to use with clip arrangements on air conditioning duct so as to improve the resistance of such clips to creep along the mating flanges (11, 12) under the influence of gravity, vibration and the like.

Abstract: New aromatic compounds containing at least one cyanate ester and at least one propargyl ether group, each independently directly attached to a ring carbon atom(s), are useful in the preparation of resins having a low dielectric constant.

Abstract: A base-catalyzed process is provided for the preparation of cyanate esters, the process including the step of pre-reacting a phenolic starting material with the basic catalyst and then reacting the pre-reaction product with a cyanogen halide. The process permits the preparation of cyanate esters in high yields at reaction temperatures above room temperature.

Abstract: New curable resin compositions comprise a (bis- or poly)-maleimide and a propargyl aromatic ether.

Abstract: New curable resin composition comprises a cyanate aromatic ester and a propargyl aromatic ether.

Abstract: Alpha, alpha', alpha"-tris(4-cyanatophenyl)-1,3,5-triisopropylbenzenes are new and useful for preparing high heat resistant resins having a low dielectric constant, particularly for electrical applications.

Abstract: A process is disclosed for preparing an advanced epoxy resin by reacting a relatively low molecular weight polyepoxide with a phenol, thiophenol, carboxylic acid or carboxylic acid anhydride in the presence of a catalytic amount of an alkyl substituted phosphonium salt such as tributyl phosphonium bromide. The process can be carried out under reaction conditions, such as the presence of water, which are deleterious to certain epoxy advancement catalysts.

Abstract: According to the invention, a relatively low molecular weight epoxy resin is reacted with a hydroxyl group-containing compound in the presence of a bis(trihydrocarbyl phosphine)iminium salt catalyst to produce a high molecular weight fusion reaction product. The process is particularly useful in reacting an epoxy resin having a molecular weight of less than about 500 with bisphenol-A in the presence of a bis(phosphine)iminium halide to produce a fusion reaction product having a molecular weight within the range of about 500 to 7000. The catalyst is relatively water-insensitive, and the reaction can therefore be carried out in the presence of water.

Abstract: The present invention provides a rapid, low-temperature curing epoxy resin adhesive composition comprising (1) a polyepoxide, (2) a catalytic amount of HBF.sub.4, (3) a finely divided filler, preferably an acidic filler, and, optionally, (4) a polyalkylene ether glycol.

Abstract: This invention relates to a flame retardant cured epoxy composition useful for electrical laminates comprising a brominated epoxy resin, aromatic amine and dicyandiamide.

Abstract: Stabilized polyester compositions comprise (1) an ethylenically unsaturated polyester prepared by esterifying a polyepoxide with an ethylenically unsaturated monocarboxylic acid (e.g., acrylic or methacrylic acid) in the presence of an organic phosphine catalyst (e.g., triphenylphosphine), (2) a primary or secondary amine (e.g., p,p'-dioctyldiphenylamine) and, optionally, (3) a compatible ethylenically unsaturated monomer (e.g., styrene).

Abstract: The present invention provides stable vinyl ester compositions exhibiting improved color stability comprising a vinyl ester resin prepared by esterifying an epoxy compound with an ethylenically unsaturated monocarboxylic acid and a stabilizer composition comprising hydroquinone and a sterically hindered phenol.

Abstract: The present invention provides an improved process for reducing the premature gelation during esterification of epoxy compounds containing tertiary, allylic or benzylic hydrogens (e.g., saturated epoxy resins) with ethylenically unsaturated monocarboxylic acids (e.g., acrylic acid) wherein the epoxy compound in pre-reacted with a trialkylphosphite (e.g., triethylphosphite) prior to the esterification.

Abstract: The present invention provides an improved process for reducing the premature gelation during esterification of epoxy compounds containing tertiary, allylic or benzylic hydrogens, e.g., saturated epoxy resins, with ethylenically unsaturated monocarboxylic acids, e.g., acylic acid, which comprises prereacting the said epoxy compound with a hydroxylamine compound prior to the esterification step.

Abstract: Chemically modified thickenable vinyl esters prepared by reacting an ethylenically unsaturated monocarboxylic acid with a polyepoxide in the presence of a small amount of a dicarboxylic acid. These resins are usually diluted with a copolymerizable monomer such as styrene, blended with a Group II metal oxide or hydroxide and other additives, and cured with a free-radical catalyst.