Coal Industry (patents) Limited

Sally A Brain

Joseph G Robinson

The present invention relates to varnishes for use in the preparation of glasscloth laminates, methods of their production and laminates made therefrom. The varnish is made by dissolving 100 parts of a TFP resin having a number average molecular weight of about 1000 and an oxygen content of about 8% in 60 to 65 parts of butan-2-one or isopropanol. 8 to 12 parts of hexamine are dissolved in a minimum quantity of a solvent comprising water and IMS in a ratio of about 3:5. The two solutions are thoroughly mixed and filtered to produce the varnish. The varnish is used to prepare glasscloth laminates for use as printed circuit boards.

Varnishes for glasscloth laminates, methods of their production and

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.

Phenolated naphthalene formaldehyde resin varnish

The invention relates to a novel resin derived from acenaphthene and to process for its production. 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-catalyzed 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.

Resin derived from acenaphthene, process for its production and

This invention relates to a method of producing a phenolated resin which can be used to form heat stable (up to 250.degree.) products. Previously used resins are either very expensive or do not provide the requisite high temperature properties. An aim of the invention is to provide a cheap equivalent to commercially available high temperature resins. An aromatic hydrocarbon (e.g. toluene) formaldehyde condensation resin is prepared. The low molecular weight contaminants are removed by a distillation process. The residue contains less than 1% low molecular weight material, and is phenolated to give the final resin. The resin may be cured to give a heat stable product. The phenolated resin may be used to form glasscloth and asbestos laminates or as a lamp capping cement.

Method of producing a resin for producing heat stable products, the

Novolak-type resins are prepared by phenolating a toluene-formaldehyde resin of oxygen content 4 - 18% and the product is reacted with hexamine to give a higher softening point of not less than 60.degree. C. The resins may be dissolved in a solvent to form a varnish; such varnishes can impregnate sheet material and laminates of good water resistance and electrical properties can be formed therefrom.

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Evesham, United Kingdom

Sally A Brain