Patent GB-1392087-A (GB)
Title: Glass fibre bundles
IPC: C08J5/08
Filed: 1972-03-30
Abstract: 1392087 Coated glass fibre bundles PPG INDUSTRIES INC 30 March 1972 [1 April 1971] 14965/72 Headings D1P and D1T [Also in Division F4]  A fibre glass bundle or a fabric formed from such bundles, suitable for reinforcing a host elastomeric material, comprises a plurality of glass filaments each encapsulated in a coating formed from an elastomeric latex containing liquid, the effective mean film thickness (as defined in the specification) of the coating being at least 9 times the mean particle diameter of the elastomeric latex. The coating forms a substantially continuous interconnecting phase throughout the bundle and comprises at least 26% by weight of the glass within the bundle. The elastomeric latex in the coating may have a particle size from 500 to 10,000 angstroms and may be selected from styrene-butadiene, vinyl pyridine terpolymer, neoprene, isoprene, butyl rubber, butadiene - styrene copolymers (styrene-butadiene rubber), acrylonitrile-butadiene-vinyl pyridine terpolymers, and mixtures thereof. The coating further comprises a resin selected from novolaks, resorcinol formaldehyde resins, phenol formaldehyde resins, and mixtures thereof. The glass fibre bundles may be in the form of strands, yarns, or cords. The fibres may be sized with a composition containing an organosilane coupling agent together with lubricants, emulsifiers, and wetting agents. A preferred method of preparing the fibre glass bundle comprises contacting a sized fibre glass bundle or fabric with a coating liquid comprising at least 28% by weight solids in water, the solids comprising from 80 to 87% elastomeric latex and from 8 to 15% resin, drying the coated bundle so as simultaneously to remove water from within the bundle and from the surface of the bundle to leave solids from the dip throughout the bundle in an amount of at least 26% by weight based on the weight of the glass in the bundle, and curing the coating throughout the bundle. As shown in Fig. 3, a plurality of glass fibre strands 5 having 1.4 turns per inch twist are drawn from bobbins 3 on a creel 1 and are passed through a ceramic guide 7 and over a plurality of motor driven roller applicators 9. The applicators, which are partially immersed in an aqueous coating emulsion in tanks 15, are driven counter to the direction of travel of the combined strand. The coated strand is passed over a wiper roller 11 and through a dielectric heater 17 (see Divisions F3-4) which selectively removes water, and thereafter traverses through a hot gas oven 21 which cures the coating. The strand is then taken up on a device 23. In an alternative method, an aqueous rubber adhesive composition containing more than 24% by wt elastomeric latex and resin is applied to individual glass fibres as they are drawn over a roller coating applicator. The coated fibres are brought together into strands and dried. The strands are then brought together into cords or rovings and further heated to cure the latex and resin and bond the strands together. Thereafter the composite glass fibre bundle may be further coated. A preferred coating dip contains, by weight, 89.7 to 139.7 parts of deionised water, 0.4 to 2.0 parts of 28% aqueous ammonium hydroxide, 10.7 to 26.7 parts of novalak resin (75% solids), 2.7. to 10.8 parts of formaldehyde (37% aqueous solution), 146 to 244 parts of styrene-butadiene-vinylpyridine latex (15:70:15) (41% solids) and 0 to 97.5 parts of styrenebutadiene rubber (41% solids). The host elastomeric material into which the coated fibre glass bundle may be incorporated may be selected from natural rubber, styrene butadiene rubber, nitrile rubber, butyl rubber, neoprene, polysulphide rubbers, polyurethane rubber, polybutadiene, cis- and trans-polybutadiene, polyisoprene, and mixtures thereof. The glass fibre is preferably used as a tyre cord for incorporation into a tyre carcass.