GB995038A - Process of adding resins to cellulose and similar fibres and product made therefrom - Google Patents

Abstract

To coat anionic fibres, e.g. cellulose fibres, in an aqueous slurry with resinous material which would not normally bond thereto, the fibrous slurry is first treated with a minor amount of a hydrophilic, altering resin containing an epoxide group which reacts with the fibres so that on the subsequent dispersion in the slurry of the resinous material in non-aqueous but fluid form the resinous material is bonded to the fibres. The following reaction products classified as Classes 1-6 are suitable for use as altering resins:-Class 1 includes resins obtained by condensing epichlorhydrin or other glycerolhalohydrin with a polyalkylene polyamine containing at least two reactive amino groups and at least four carbon atoms; Class 2 includes the product of a reaction between a low molecular weight polyamide of a polyalkylene polyamine and a dicarboxy acid with a glycerolhalohydrin; Class 3 includes the products of reaction of an alkylene polyamine having at least four carbon atoms and at least two reactive amino groups with a resinous epoxide having alternating aliphatic chains and aromatic nuclei; Class 4 includes the product obtained by reacting an alkylene polyamine having at least four carbon atoms and at least two reactive amino groups with a polyepoxide and further reacting with an additional quantity of polyepoxide; Class 5 resins are prepared as Class 3 resins but with the additional step of reacting with formaldehyde, para-formaldehyde or a formaldehyde liberating compound; Class 6 resins are prepared as Class 4 resins but with the additional step of reacting with formaldehyde, para-formaldehyde or other formaldehyde liberating compound. The most effective altering resins are those containing a lipophilic group of at least six carbon atoms, containing a substantial quantity of epoxide groups, and which are of relatively high molecular weight and the resins of Classes 4-6 are therefore of particular value. The slurry to which the altering resin is added is usually of a consistency of 0,5-6% by weight of fibres and the resin is added in amounts ranging from 0,5-5% of the weight of fibres and may be added in the form of a solution in hydrochloric acid. The resinous material is added in the form of a solution in an organic solvent. The resins which may be used to coat the fibres include polyester resins and hydrocarbon resins, the latter including polystyrene, styrene butadiene copolymers and petroleum resins especially dicyclopentadiene. Asphalt, and mineral spirits-soluble vinyl aromatic-olefinic interpolymers may also be used as resinous materials to be bonded to the fibres. Altering resins of Classes 1-3 produce an affinity for the polyester type resins but not for the hydrocarbon resins. However it is possible to treat the fibres first with a polyester type resin employing an altering resin from Classes 1-3 and then subsequently to add a hydrocarbon resin. Heating of the aqueous slurry to a temperature between 140 DEG F. and 200 DEG F. while effecting the dispersion of the resinous material in the slurry may be employed to increase the effectiveness of the coating of the fibres.ALSO:Paper, paper board or moulded fibrous products may be prepared from a slurry of anionic fibres, e.g. cellulose fibres, the slurry having been treated first of all with a minor amount of a hydrophilic altering resin containing an epoxide group which reacts with the fibres to allow them to be coated with resinous material which normally would not bond to the fibres, and which is subsequently dispersed in the slurry in non-acqueous but fluid form. The altering resins, of which six classes are referred to, are generally prepared by the reaction of polyalkylene polyamines and alkylene polyamines having at least four carbon atoms and at least two reactive amino groups; with a polyepoxide having an epoxide equivalent of at least 43 to form a cationic hydrophilic condensation product having an epoxide equivalent of about 200 to 2000. The slurry to which the altering resins is added is usually of a consistency of 0.5% to 6% by weight of fibres and the resin is added in amounts ranging from 0.5% to 5% of the weight of fibres and may be added in the form of a solution in hydrochloric acid. The resinous material is added in the form of a solution in an organic solvent. The resins which may be used to coat the fibres include polyester resins and hydrocarbon resins, the latter including polystyrene, styrene butadiene copolymers and petroleum resins especially dicyclopentadiene. Asphalt, and mineral spirits-soluble vinyl aromatic-olefinic interpolymers may also be used as resinous materials to be bonded to the fibres. Altering resins of Classes 1-3 produce an affinity for the polyester type resins but not for the hydrocarbon resins. However it is possible to treat the fibres first with a polyester type resin employing an altering resin from Classes 1-3 and then subsequently to add a hydrocarbon resin. In Example II luggage shells are felted and die dried from a slurry of cellulosic fibres and fibreglass fibres the slurry having been treated with phenol formaldehyde resin. In Example III a cellulose fibre slurry treated with a polyester resin is used to prepare phonograph cabinets. In Example IV a packaging block having a shaped cavity is prepared from cellulosic fibre treated with an oleoresinous varnish. In Example VIII a luggage shell is moulded from cellulosic fibres treated with phenol formaldehyde resin.