The United States of America As Represented by the Administrator of the

The United States of America As Represented by the United States

Donald J Progar

Terry L St Clair

Robert L Fox

J Richard Pratt

Robert H Coultrip

John D Buckley

Harold D Burks

Bruce D Little

Vernon L Bell

John R Gleason

Richard H Couch

Alan W Frizzill

Bland A Stein

The invention is a novel polyimide prepared from 3,4'-oxydianiline (3,4'-ODA) and 4,4'-oxydiphthalic anhydride (ODPA), in 2-methoxyethyl ether (diglyme). The polymer has been prepared in ultra high molecular weight and in a controlled molecular weight form which has a 2.5 percent offset is stoichiometry (excess diamine) with a 5.0 percent level of phthalic anhydride as an endcap. This controlled molecular weight form allows for greatly improved processing of the polymer for moldings, adhesive bonding, and composite fabrication. The higher molecular weight version affords tougher films and coatings. The overall polymer structure groups in the dianhydride, the diamine, and a metal linkage in the diamine affords adequate flow properties for making this polymer useful as a molding powder, adhesive, and matrix resin.

Polyimide molding powder, coating, adhesive and matrix resin

A high temperature polyimide composition prepared by reacting 4,4'-isophthaloyldiphthalic anhydride with metaphenylenediamine is employed to prepare matrix resins, adhesives, films, coatings, moldings, and laminates.

Processable polyimide adhesive and matrix composite resin

Novel copolyimides are prepared by reacting one or more aromatic dianhydrides with a meta-substituted phenylene diamine and an aromatic bridged diamine. The incorporation of meta-substituted phenylene diamine derived units and bridged aromatic diamine derived units into the linear aromatic polymer backbone results in a copolyimide of improved flexibility, processability, and melt-flow characteristics. The novel copolyimides are especially useful as thermoplastic hot-melt adhesives.

Copolyimide with a combination of flexibilizing groups

The invention relates to a hot melt adhesive attachment pad for releasably securing distinct elements together and particularly useful in the construction industry or a spatial vacuum environment. The attachment pad consists primarily of a cloth 11 selectively impregnated with a charge of hot melt adhesive 12, a thermo-foil heater 13 and a thermo-cooler 14. These components are securely mounting in a mounting assembly 17 and 18. In operation, the operator activates the heating cycle transforming the hot melt adhesive to a substantially liquid state, positions the pad against the attachment surface, and activates the cooling cycle solidifying the adhesive and forming a strong, releasable bond.

Hot melt adhesive attachment pad

A package assembly for precisely positioning a charge of hot melt adhesive 37 onto an attachment pad (13, 15, 17) or point of use wherein the adhesive is heated to softening or melt temperature (280.degree. F.-325.degree. F.) and thereafter cooled to resolidifying temperature. A single sided pressure sensitive polyimide film tape 40 serves with another film strip 39 to protect sandwiched adhesive strip 37 until use and to hold the adhesive in precise position until thermally bonded to its point of use. Tab ends 39' and 40' serve as aids in stripping tapes 39 and 40, respectively, from the adhesive charge 37.

Hot melt recharge system

A process of preparing aromatic polyamide-acids for use as adhesives by reacting an aromatic dianhydride to an approximately equimolar amount of an aromatic diamine in a water or lower alkanol miscible ether solvent and wherein the polyamide-acids are converted to polyimides by heating to the temperature range of 200.degree. - 300.degree. C. and wherein the polyimides are thermally stable and insoluble in ethers and other organic solvents.

Growing community of inventors

Grafton, VA, United States of America

Donald J Progar