Multilayer pipe comprising at least a first layer and a second layer, wherein the first layer is comprised a first polymer have a first thermal stability, and the second layer is comprised of a second polymer having a second thermal stability that is improved relative to said first thermal stability. In one exemplary embodiment, the first layer is comprised of PVC or CPVC, and the second layer is comprised of polycarbonate.

Provided herein are polyethylene compositions suitable in the fabrication of PE-RT pipes for use in cold and hot water plumbing in accordance with ISO 22391-2, and processes for making the same.

Provided herein are polyethylene compositions suitable in the fabrication of PE-RT pipes for use in cold and hot water plumbing in accordance with ISO 22391-2, and processes for making the same.

Provided are: a multilayer structure having a strong initial interlayer adhesive force, with a decrease of the interlayer adhesive force being prevented even in a case of use in a harsh environment such as exposure to hot water, an acid, or an alkali for a long period of time; a method for producing such a multilayer structure; and a sheet for preventing diffusion of hazardous substances, a landfill geomembrane, and a multilayer pipe, each including such a multilayer structure. A multilayer structure includes: one or a plurality of layer (A) constituted from a resin composition (A) containing an ethylene-vinyl alcohol copolymer (a) as a principal component; and one or a plurality of layer (B) constituted from a resin composition (B) containing a modified polyolefin (b) which has a basic nitrogen-containing group, wherein the ethylene-vinyl alcohol copolymer (a) has at least one of a carboxy group and a lactone ring, and a total amount of the carboxy group and the lactone ring with respect to a total amount of an ethylene unit, a vinyl alcohol unit, and a vinyl ester unit of the ethylene-vinyl alcohol copolymer (a) is 0.08 mol% or more and 0.4 mol% or less.

This method for manufacturing a pipe (2) for a vehicle fuel tank involves—molding a wall, comprising an inner layer (6) made from ethylene vinyl alcohol (EVOH) and an outer layer (8) made from a polymer suitable for welding, in a mold comprising at least one female shoulder that creates at least one male shoulder on an outer surface of an end portion of the wall during molding, then—cutting off the end portion of the wall.

A pipe (10) includes a polyethylene-based resin layer (21) containing a polyethylene-based resin composition as a major component. The polyethylene-based resin layer (21) forms a pipeline member inner surface (10a). The polyethylene-based resin composition has a calcium concentration of 10 ppm or more and 60 ppm or less.

A pipe (10) includes a polyethylene-based resin layer (21) containing a polyethylene-based resin composition as a major component. The polyethylene-based resin layer (21) forms a pipeline member inner surface (10a). The polyethylene-based resin composition has a calcium concentration of 10 ppm or more and 60 ppm or less.

A system for coupling pipes includes a first pipe having a tapered, spigot end; a second pipe having a tapered, spigot end; a coupler having two tapered socket ends adapted to internally receive the respective tapered, spigot ends of the first pipe and the second pipe; and a resistive element. The first pipe, the second pipe, and the coupler are made from a reinforced thermosetting resin (RTR). The resistive element includes a first layer and a second layer of thermoplastic material; and an electrically conducting resistive heating element with positive and negative terminals for connecting electrical power. The electrically conducting resistive heating element is sandwiched by the first layer and the second layer of thermoplastic material. The resistive element is disposed between an interior of the coupler and at least one of: an exterior of the first pipe and an exterior of the second pipe. Upon application of electrical power to the positive and negative terminals of the resistive element, the electrically conducting resistive heating element generates heat sufficient to melt the thermoplastic material such that, when the heat is removed, the hardened thermoplastic material seals the first pipe and/or the second pipe to the coupler.

A method of manufacturing a composite connector for a fluid transfer conduit is provided which comprises applying continuous fibre reinforcement, oriented at least partially circumferentially and pre-impregnated with a thermoplastic polymer to a tubular mould portion which extends substantially parallel to a central axis C; applying at least one further mould portion to form a complete mould in which the continuous fibre reinforcement is enclosed and injecting a thermoplastic polymer into the mould to form a connector with a tubular hub portion and a flange portion which extends from the hub portion at an angle to the central axis C. The tubular hub portion comprises a tubular seal section with an inner layer and an outer wherein the inner layer comprises the continuous fibre reinforcement and the outer layer comprises the injected thermoplastic polymer.

A method of manufacturing a composite connector for a fluid transfer conduit is provided which comprises applying continuous fibre reinforcement, oriented at least partially circumferentially and pre-impregnated with a thermoplastic polymer to a tubular mould portion which extends substantially parallel to a central axis C; applying at least one further mould portion to form a complete mould in which the continuous fibre reinforcement is enclosed and injecting a thermoplastic polymer into the mould to form a connector with a tubular hub portion and a flange portion which extends from the hub portion at an angle to the central axis C. The tubular hub portion comprises a tubular seal section with an inner layer and an outer wherein the inner layer comprises the continuous fibre reinforcement and the outer layer comprises the injected thermoplastic polymer.