| 摘要 |
A layered tubing for use in beverage carrying and dispensing composed of a thicker outer layer, a thin intermediate bonding layer and the innermost impermeable and nonreactive barrier layer is disclosed. This invention relates to a new and economically viable method for making a Thermoplastic Multilayer Tubing which is comprised of layer's in which the inner layer P.J .1 is a Barrier layer which does not allow the permeation and diffusion of vapours, gases, moisture; aroma and flavours. The P.J.1 layer which is totally inert, odourless, non-soluble in water, alcohols, beverages, syrups and alike is the beverage contact layer. The P.J.1 is a copolyester with a general formula (C10H8O4)n without any hazardous ingredients and has a melting point range about 160.degree.C and density between 0.9 and 1.0 g/ml. In one construction, the P.J.1 layer is bonded to Ethylene Vinyl Alcohol (EVOH) by a bonding layer P.J.2 which is Polyethylene copolymer with modified polyolefin having approximately % C = 79.2, % H =13.6, %O = 7.6, with trace amounts of N, melting point range 104 - 138.degree.C and specific gravity 0.91 - 0.95 (water = 1). The bonding material is chemically stable under the processing conditions. The outer surface layer is comprised of polyethylene, P.E., with a general formula (C2H4)n havinga melting point range of about 180.degree.C. It is bonded to the EVOH layer by P.J.3 which is modified polyolefin. This is referred to as the Class I tubing of this invention. In another class of tubing, which is referred to as the Class II tubing of this invention, the outer surface layer is comprised of polyethylene, P.E., with general formula (C2H4)n having melting point range about 180.degree.C. It is bonded to the impermeable P.J. 1 layer by the P.J.4 layer which is a chemically stable plastic material under processing conditions, having a general formula (C8H16O)n, density of about 0.9, and melting point of about 55.degree.C. The applicants have developed processing conditions for the inner layer P.J. 1, and a suitable method for making the beverage tubing and film which meet the attributes of desired tubing and film and solve the long standing problem of vapour and flavour transmission and adsorption in the transfer of flavoured beverages. The film form of P.J.1 ca n also find its application in the food packaging industry to prevent loss of moisture, flavour and taste. The realization is that P.J.1 is environmentally friendly for beverage holding a nd dispensing and is envisioned to have numerous potential applications now, and in the new millennium with increasing demand for such tubing. These applications can utilize the unique properties of the P.J.1 layer in an environmentally friendly and cost-effective manner.</S DOAB>
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