The present invention provides a structure that improves sound absorption coefficient. The present invention provides a structure comprising: a foam resin layer formed of a foam material having a foaming ratio of 1.1 to 8 times; and a sound absorbing layer formed of a foam material having a foaming ratio of 10 to 30 times, the sound absorbing layer laminated on the foam resin layer.

The present invention provides a structure that improves sound absorption coefficient. The present invention provides a structure comprising: a foam resin layer formed of a foam material having a foaming ratio of 1.1 to 8 times; and a sound absorbing layer formed of a foam material having a foaming ratio of 10 to 30 times, the sound absorbing layer laminated on the foam resin layer.

A plastic line including at least an inner layer, which directly or indirectly encloses an interior space, and an outer layer directly adjacent to the inner layer. The inner layer is based on fluoropolymer, and the outer layer consists of the following constituents: (A) 51-98% of a polyamide from the following group: PA 616, PA 516, PA 618 or mixtures thereof, and copolymers containing at least 50% of at least one of these polyamides and also mixtures of at least one of these polyamides with a further different thermoplastic material (A2), wherein the proportion of these polyamides in such mixtures makes up at least 50%; (B) 2-20% of impact modifiers or plasticizers; (C) 0-29% of additives different from (A) and (B), wherein the components (A)-(C) together make up 100% of the material of the outer layer.

A method of joining segments of non-metallic pipe and an apparatus that may be used to form the joint. The pipes may be joined using by melting the ends to form a butt joint, then the joint may be wrapped with one or more sheets of reinforcement material (e.g., pre-impregnated fiberglass, carbon fiber, or aramid fiber). The reinforcement material may be heated using a heating apparatus which allows the material to bond to the pipes to strengthen the joint.

Provided is piping for ultra-pure water from which the amount of calcium leaching can be suppressed to an extent that satisfies the quality required for ultra-pure water, and which can be produced so as to be provided with mechanical properties.

[Solution] This piping for ultra-pure water is used for conveying ultra-pure water and includes a first polyolefin-based resin layer constituting the innermost layer, and a second polyolefin-based resin layer disposed on the outer side of the first polyolefin-based resin layer, wherein the calcium concentration within the first polyolefin-based resin layer is 10 ppm or lower, and the calcium concentration within the second polyolefin-based resin layer is between 20 ppm and 200 ppm inclusive. With this constitution, the amount of calcium leaching can be suppressed to an extent that satisfies the quality required for ultra-pure water, and the piping can be produced so as to be provided with mechanical properties.

Provided is piping for ultra-pure water from which the amount of calcium leaching can be suppressed to an extent that satisfies the quality required for ultra-pure water, and which can be produced so as to be provided with mechanical properties.

[Solution] This piping for ultra-pure water is used for conveying ultra-pure water and includes a first polyolefin-based resin layer constituting the innermost layer, and a second polyolefin-based resin layer disposed on the outer side of the first polyolefin-based resin layer, wherein the calcium concentration within the first polyolefin-based resin layer is 10 ppm or lower, and the calcium concentration within the second polyolefin-based resin layer is between 20 ppm and 200 ppm inclusive. With this constitution, the amount of calcium leaching can be suppressed to an extent that satisfies the quality required for ultra-pure water, and the piping can be produced so as to be provided with mechanical properties.

The invention relates to production of long spiral-welded large polymer products, as required for pipelines production, chemical, oil and gas and petrochemical industries, agricultural complex and utility services. The object of the invention is to create variants of spiral-welded polymer product with a cellular wall, having the internal or external, or internal and external uniform smooth walls with little material consumption, weight and cost. It should allow making products on site due the use of a thin-walled, lightweight, flexible profile. The object is solved owing to fact that a long hollow thermoplastic profile is used in spiral-welded polymer products, wherein the cross-section of the profile has a form of a closed geometric figure with a convex part having essentially the semi-ring shape and flat part that are connected each other, forming the convex and flat parts of the external surface of the profile, respectively.

The invention relates to production of long spiral-welded large polymer products, as required for pipelines production, chemical, oil and gas and petrochemical industries, agricultural complex and utility services. The object of the invention is to create variants of spiral-welded polymer product with a cellular wall, having the internal or external, or internal and external uniform smooth walls with little material consumption, weight and cost. It should allow making products on site due the use of a thin-walled, lightweight, flexible profile. The object is solved owing to fact that a long hollow thermoplastic profile is used in spiral-welded polymer products, wherein the cross-section of the profile has a form of a closed geometric figure with a convex part having essentially the semi-ring shape and flat part that are connected each other, forming the convex and flat parts of the external surface of the profile, respectively.

A multilayer tube (1) includes: an elastic layer (11, 21, 31, 41, 51) formed over the entire length of the multilayer tube (1) and having a predetermined flexural modulus of elasticity; and a hard layer (12, 22, 32, 42, 52) formed over the entire length of the multilayer tube (1), having a flexural modulus of elasticity that is high compared to the elastic layer (11, 21, 31, 41, 51), and disposed more to an outer layer side than the elastic layer (11, 21, 31, 41, 51). A first extremity (10) of the multilayer tube (1) is formed in such a manner that the thickness (H11) of the elastic layer (11) is thicker than the thickness (H12) of the hard layer (12).

A multilayer tube (1) includes: an elastic layer (11, 21, 31, 41, 51) formed over the entire length of the multilayer tube (1) and having a predetermined flexural modulus of elasticity; and a hard layer (12, 22, 32, 42, 52) formed over the entire length of the multilayer tube (1), having a flexural modulus of elasticity that is high compared to the elastic layer (11, 21, 31, 41, 51), and disposed more to an outer layer side than the elastic layer (11, 21, 31, 41, 51). A first extremity (10) of the multilayer tube (1) is formed in such a manner that the thickness (H11) of the elastic layer (11) is thicker than the thickness (H12) of the hard layer (12).