Patent GB-987933-A (GB)
Title: Pressure-sensitive adhesive tapes
IPC: C09J7/38
Filed: 1961-04-18
Abstract: A breathable surgical adhesive tape comprises (A) a tissue-like web of randomly interlaced staple textile fibres which are individually coated and are interbonded at their crossing points by a non-tacky hydrophobic rubbery fibre-sizing polymer to provide water-repellent sized fibres and wet strength in a unified resilient reticular tissue-like fabric backing having a porous capillary structure capable of absorbing liquid perspiration and which is strong and tough enough for surgical tape functioning whether dry or wet; and (B) a smooth visibly-continuous hydrophobic skin-adhering pressure-sensitive adhesive coating upon and interlocking with the fibres of one side of the backing to provide a unitary uniform but micro-porous fibro-adhesive web structure, the adhesive coating having a multitude of randomly-varying minute closely spaced pores communicating with the interfilar backing pores and sufficing to transmit perspiration in either liquid or vapour state when the tape is adhered to human skin such that the entire contacted skin area is maintained in a dry ventilated state under ordinary conditions; the adhesive coating essentially consisting of a water-insoluble hydrophobic rubbery pressure-sensitive adhesive polymer, the adhesive having a composition that is relatively non-irritating to the human skin and being so firm and rubbery that the tape can be readily and comfortably removed from the skin after prolonged adhering contact. The fibre-sizing polymer, which may be a non-tacky rubbery acrylate polymer, may be present in a proportion of 30-70% of the total fabric weight.  The adhesive, which may be transparent or translucent, may be a copolymer of isooctyl acrylate and acrylic acid which may be present in the ratio 94:6 by weight.  The adhesive coating may have a weight of the order of 50 pounds per 1000 square yards.  The interlaced fibres may be of polyester or rayon, having a length of 1-2 inches, and the tissue-like web may have a weight of 75-100 pounds per 1000 square yards.  The tape may have a caliper thickness of 4-6 mils. The tape may be produced by applying a continuous viscid coating of a solution or partially dried solution of water-insoluble viscoelastic pressure-sensitive adhesive containing a volatile vehicle to a non-woven compacted tissue backing of porous capillary structure formed of interlaced staple textile fibres individually coated and interbonded at their crossing points by a water-insoluble rubbery fibre-bonding sizing agent, and thereafter completely drying the adhesive coating, the proportion of volatile vehicle being such that during drying the applied adhesive coating does not penetrate through the porous backing.  The adhesive solution may be applied to a liner web having a shiny-smooth anti-stick surface and thereafter partially drying the adhesive coating, superimposing on it the porous backing web, completely drying the adhesive and subsequently removing the liner web.  The proportion of volatile vehicle in the partially dried adhesive coating may be such that during the final drying the adhesive penetrates into but not through the porous backing.  The adhesive coating may be transparent and consist solely of viscoelastic pressure-sensitive adhesive polymers and a volatile vehicle.