Heat insulation cover member for drip prevention or drip suppression of dew condensation water, covering member for other heat exchange pipes and ducts, piping structure and duct covering structure using same, electrical device box covering structure, nonwoven fabric to be used in said heat insulation cover member and method for using said nonwoven fabric in heat insulation cover member, and method for using said heat insulation cover member for various covering members including heat exchange pipe covering member

Abstract

Provided is a heat insulation cover member for drip prevention or drip suppression of dew condensation water in which a nonwoven fabric is disposed on the surface of a resin foam. The heat insulation cover member for drip prevention or drip suppression of dew condensation water, in which the nonwoven fabric is joined to the surface of the resin foam, is characterized in that: the resin foam is a polyethylene resin foam that has closed cells; the nonwoven fabric is affixed to one surface of the resin foam by fusion or bonding; the nonwoven fabric is composed of a nonwoven fabric in which a specific amount of highly water absorbent resin fibers is mixed with thermoplastic resin fibers; at least some of the thermoplastic resin fibers are fused or bonded with each other; and the highly water absorbent resin fibers are contained in an amount of 10% by mass to 80% by mass inclusive, while the thermoplastic resin fibers are contained in an amount of 20% by mass to 90% by mass inclusive. The invention of a covering member for other heat exchange pipes and ducts, a piping structure and a duct covering structure using the same, an electric device box covering structure, and a method for using a nonwoven fabric and a heat insulation cover member is also included.

Description

Thermal insulation cover members for preventing or suppressing dripping of condensation water, other heat exchange piping cover members and duct cover members, piping structures and duct cover structures using these, electrical equipment box cover structures, nonwoven fabrics used for the thermal insulation cover members and methods for using the nonwoven fabrics for thermal insulation cover members, and methods for using the thermal insulation cover members for various cover members including heat exchange piping cover members

[0001] The present invention relates to a heat-insulating cover member for preventing or suppressing dripping of condensation water, other heat exchange piping cover members and duct cover members, piping structures and duct cover structures using these, electrical equipment box cover structures, nonwoven fabrics used for the heat-insulating cover members, methods for using the nonwoven fabrics for heat-insulating cover members, and methods for using the heat-insulating cover members for various cover members including heat exchange piping cover members.

[0002] In recent years, the increasing heat and efficiency of air conditioning systems have led to the emergence of problems caused by condensation dripping from concealed refrigerant pipes. This dripping can cause peeling and darkening of ceiling wallpaper and floors. A typical covering material for such heat exchanger pipes is a polyethylene foam with a polyethylene or polypropylene film laminated to at least one surface, followed by an embossed surface. This type of covering material, however, can cause condensation on the surface of the covering material used around the refrigerant pipes. Dripping this condensation into the piping space above the ceiling can lead to mold growth in the piping space. While the purpose and application of the countermeasures vary, the following inventions, including those related to covering materials and nonwoven fabrics, are useful references.

[0003] Patent Document 1 discloses the following: A covering body containing a covering material of a desired thickness is applied to a surrounding covering layer of a metal duct body, a synthetic resin flexible tube, an aluminum flexible tube, a duct body having a surrounding covering layer, a flexible tube, etc. A heat-insulating / cold-insulating covering material of a desired thickness, such as glass cloth, nonwoven wool, or cotton-like pulp, which is capable of preventing or suppressing condensation and is impregnated with a highly water-absorbent polymer water-absorbing material, is applied to the covering body. In other words, the pipe structure disclosed in Patent Document 1 has a heat-insulating / cold-insulating covering layer that prevents or suppresses condensation and increases water retention to eliminate condensation. Conversely, the pipe structure disclosed in Patent Document 1 needs to ensure the insulating function of the heat-insulating / cold-insulating covering layer in order to achieve heat-insulating / cold-insulating performance without forming a foam layer, as can be seen from the fact that the glass cloth, nonwoven wool, cotton-like pulp, etc., impregnated with a polymer water-absorbing material, is wrapped around the covering body to a thickness different from that of the present invention. The structure of Patent Document 1 is a tubular structure in which the heat and cold insulation covering layer, which is made of glass cloth, nonwoven wool, cotton-like pulp, or other material capable of preventing or suppressing condensation, is covered with a surface covering layer that contains a highly fire-resistant material such as fluorine resin or zirconium to enhance fire resistance. The tubular structure of Patent Document 1 has a surface covered with a nonwoven fabric impregnated with a polymeric water-absorbing material. Unlike the present invention, which does not have a nonwoven fabric bonded to the surface of a polyethylene-based resin foam, or which does not use superabsorbent resin fibers, the two structures differ in the structure structure in addition to the necessity of a resin foam. Furthermore, the technical concept differs between the two structures in the use of a resin foam in the insulation layer. In other words, Patent Document 1 requires insulation performance to be achieved using only a fibrous material such as a nonwoven fabric without using a resin foam. Furthermore, Patent Document 1 does not disclose any mention of preventing condensed water from agglomerating at a specific location and promoting water evaporation by diffusion, such as the moisture retention parameter of a nonwoven fabric.

[0004] Patent Document 2 discloses an insulating pipe cover comprising a sheet in which a synthetic resin sheet outer skin is laminated onto the surface of a rectangular thermoplastic resin foam, the outer skin of the laminated sheet being provided at one end of the foam sheet, protruding beyond the end of the foam sheet to form an overlap. The overlap is bonded to the outer skin via a release sheet, with a portion of the adhesive layer covered by a protective layer. The invention of Patent Document 2 aims to provide an insulating pipe cover that can be easily installed on a pipe even while wearing work gloves due to the synergistic effect of the protective layer and the release sheet, and that has a structure that significantly reduces thermal degradation of the cut area after installation, as well as a covering method and an insulating pipe covering structure using the same. The purpose of the insulating pipe cover of Patent Document 2 is to simplify installation and improve heat resistance, not to prevent or suppress dripping of condensation water. Therefore, the detailed description of the invention in the specification only discloses thermoplastic resin films and thermoplastic resin sheets as protective layers, but makes no mention of nonwoven fabrics. That is, while Patent Document 2 claims nonwoven fabrics as an example of a material that could potentially be used as a protective layer or release sheet, it treats non-absorbent thermoplastic resin sheets and resin films in the same category as absorbent materials such as paper, woven or knitted fabrics, and nonwoven fabrics. Since any material can be used as a surface coating material to form a protective layer, there is no mention of the structure or characteristics of nonwoven fabrics. Patent Document 2 discloses an insulating pipe cover using a foam, but its application is simple and its purpose is to prevent thermal deterioration of the breaks (joints at the ends) of the foam. It is not an insulating cover member intended to prevent or suppress the dripping of condensation water by laminating a nonwoven fabric made of a mixture of synthetic fibers and highly absorbent resin fibers to the surface of the foam. Furthermore, no specific structure is disclosed for the nonwoven fabric, and it is treated in the same category as a resin film used as a surface coating material for a protective layer. The invention does not intend to impart special functions to the nonwoven fabric by taking into consideration the structure and material properties of the nonwoven fabric.Therefore, Patent Document 2 does not disclose at all how to balance the water retention and diffusive evaporation properties of a nonwoven fabric by using a moisture retention parameter of the nonwoven fabric, which prevents the aggregation of condensed water and promotes evaporation of water by diffusion, and does not provide any motivation to do so.

[0005] Patent Document 3 discloses the following invention. Research was conducted into the heat retention and water absorption properties of thermal insulation cover members by combining various films and nonwoven fabrics. As a result, a porous polyolefin film and a nonwoven fabric containing a highly water-absorbent polymer were laminated together. It was found that when water droplets dripped onto the film surface and dripped through the holes in the porous film, the condensation water was absorbed within 60 seconds. A water-absorbent agricultural cover member characterized by this was disclosed. The water-absorbent agricultural cover member of Patent Document 3 is primarily intended to be laid between strawberries in greenhouse-grown strawberry rows so that the strawberries can bear fruit on top. It suppresses water evaporation from the ground, and is an invention that primarily emphasizes water retention. The thermal insulation cover member of Patent Document 3 is an invention for an agricultural insulation material in which a porous resin film is laminated with a nonwoven fabric containing a highly water-absorbent polymer. To maintain the quality of strawberries, the film surface absorbs water droplets within 60 seconds, preventing evaporation and retaining the condensation water. However, unlike the present invention, this does not achieve a balance between condensation water retention and evaporation using a nonwoven fabric. That is, the invention of Patent Document 3 covers the surface of a nonwoven fabric with a porous resin film, allowing the nonwoven fabric to retain condensation water while simultaneously preventing evaporation, thereby preventing deterioration in strawberry quality. The invention of Patent Document 3 does not use a laminated structure of a resin foam and a nonwoven fabric as in the present invention, but rather a laminated structure of a porous resin film and a nonwoven fabric, and the two inventions are structurally different. Furthermore, since the surface of the invention of Patent Document 3 is covered with a resin film, it may be easier to retain absorbed water, but the resin film coating layer prevents evaporation, which hinders its use for promoting evaporation to prevent condensation as in the present invention. Therefore, there is no description whatsoever of preventing the aggregation of condensed water and promoting evaporation of water by diffusion, such as the moisture retention parameter of a nonwoven fabric. Furthermore, while Patent Document 3 states that the blending ratio of BELLOASIS, which is a superabsorbent resin fiber, is within the range of 1% by mass to 10% by mass, the product of the present invention is different in that, as will be described later, the blending ratio of the superabsorbent resin fiber in the layer containing the superabsorbent resin fiber is 10% by mass to 80% by mass.

[0006] Patent Document 4 describes a multifunctional absorbent sheet comprising three components: an absorbent layer primarily composed of a superabsorbent polymer; a nonwoven fabric substrate supporting the superabsorbent polymer; and a binder component binding the superabsorbent polymers together and between the superabsorbent polymer and the substrate. The invention of Patent Document 4 is a multifunctional absorbent sheet having a multilayer structure, which is used in absorbent products such as baby diapers, adult diapers, female incontinence products, blood absorbents, and breast pads. The absorbent sheet of Patent Document 4 discloses a multifunctional absorbent sheet having a multiphase structure characterized in that an absorbent region phase (phase A) consisting of an absorbent layer and a nonwoven fabric substrate supporting it, and a diffusion / acquisition region phase (phase B) consisting only of the nonwoven fabric substrate and in which the superabsorbent polymer is hardly present, are distributed on the surface of the sheet absorbent so as to be mutually distinguishable. Patent Document 4 discloses a two-layer laminated nonwoven fabric, in which one layer contains a superabsorbent polymer and the adjacent nonwoven fabric is composed of synthetic resin fibers. The superabsorbent polymer layer in Patent Document 4 uses granular superabsorbent polymer. Therefore, a binder is required to bond the nonwoven fabric fibers and the granular superabsorbent polymer. In contrast, the present invention uses superabsorbent polymer fibers, eliminating the need for a binder due to the entanglement of the skeletal fibers and the superabsorbent polymer fibers. The nonwoven fabric layer in Layer B is composed of a bulky, high-resilience acquisition layer (elastic recovery rate) for improving moisture permeability, with the aim of diffusing and acquiring moisture. In contrast, the layer not containing superabsorbent polymer in the present invention is intended to diffuse and evaporate moisture. Furthermore, the moisture retention parameter of the nonwoven fabric prevents condensation and promotes moisture evaporation through diffusion, thereby achieving a balance between the water retention and diffusion / evaporation properties of the nonwoven fabric. Patent Document 4 does not include such a description and differs in that it aims to diffuse moisture and capture it in the superabsorbent resin layer. The structure of the water-absorbent nonwoven fabric itself is different, and in Patent Document 4, when only the nonwoven fabric is used as the heat-retaining cover member, the insulating effect of the resin foam cannot be obtained, and therefore the amount of condensation water in the nonwoven fabric layer increases.

[0007] Patent Document 5 discloses an absorbent composite with a thickness-wise gradient of absorbency, which is formed by integrating a first layer made of a nonwoven fabric web primarily composed of synthetic fibers with surface wetting properties to moisture with a second layer made of a shape-stabilized superabsorbent polymer sheet with significantly higher moisture retention than the first layer. Patent Document 5 also describes that liquid supplied to the first layer is momentarily received by the first layer, but quickly passes through without being retained there, and is absorbed and stably absorbed by the second layer, so that the first layer is always ready for the next excretion, making it advantageous for many applications, including diapers and sanitary napkins. Patent Document 5 also discloses that by connecting the layers of a multilayered sheet and fiberizing the second main absorbent layer, the shape stability of the laminated nonwoven fabric is improved, thereby providing a sheet-like composite absorbent body with extremely high liquid absorption efficiency and excellent shape stability even after liquid absorption. The sheet-like composite absorbent body with laminated nonwoven fabrics described in Patent Document 5 has a first layer formed from a nonwoven fabric web primarily composed of synthetic fibers with surface wetting properties to moisture. The second layer is a composite nonwoven fabric obtained by hydroentangling precursor fibers to a polypropylene fiber-based framework, and then subjected to a high-absorbency treatment to form a shape-stabilized, highly water-absorbent polymer sheet. As a result, the water-absorbent composite of Patent Document 5 has a gradient in absorbency between the first and second layers, which allows excreted liquid to be instantly absorbed by the first layer. It then quickly passes through without being retained there, and is absorbed into the second layer for stable absorption. Patent Document 5 states that, when viewed as a laminated structure, it is preferable for the first layer to have high permeability to the second layer, but does not describe the diffusibility of the first layer toward the surface of the nonwoven fabric. Unlike the thermal insulation cover member for preventing or suppressing dripping of condensation water from refrigerant pipes of air conditioners and the like of the present invention, the invention of Patent Document 5 is a diaper with high absorbency made solely of a laminated nonwoven fabric, and the two inventions have different objectives. Therefore, the invention of Patent Document 5 does not require an insulating layer to prevent condensation like the present invention, and the two differ structurally in that one has a laminated structure of resin foam and nonwoven fabric, while the other has a structure composed only of nonwoven fabric.The present invention has a laminated structure of resin foam and nonwoven fabric, and thus differs from the invention of Patent Document 5, which only focuses on nonwoven fabric, in that the protective and insulating effects of the resin foam are superimposed. Furthermore, the present invention considers not only water retention but also the balance between the water retention and diffusive evaporation properties of the nonwoven fabric through the moisture retention parameter of the nonwoven fabric, which prevents the aggregation of condensation water and promotes water evaporation through diffusion. On the other hand, while Patent Document 5 describes the water absorption capacity gradient between the first and second layers and the water retention of the second layer, it does not describe the mechanism by which water is diffused and evaporated, and therefore does not aim to prevent condensation by promoting diffusion and evaporation from the outer surface of the protective member. Furthermore, the cover member of the present invention utilizes the ability of superabsorbent resin fibers to not only absorb water in response to changes in temperature and humidity but also release water in a dry state, while Patent Document 5 differs in that it is only intended for water absorption.

[0008] JP 09-049587 JP 09-001710 JP 09-300511 JP 2000-201975 JP 07-155594

[0009] For refrigerant pipes and drain pipes in heat exchangers such as air conditioners, polyethylene resin foams with a polyethylene film laminated to the surface and an embossed surface are being considered for use as thermal insulation coverings for these pipes. However, this method poses the problem of condensation in harsh operating environments. To address this issue, a method has been proposed in which a nonwoven fabric impregnated with a polymeric water-absorbing material is directly laminated to the duct or pipe to prevent condensation. Covering materials made solely of nonwoven fabric require the nonwoven fabric to provide sufficient thermal insulation. This requires a thicker nonwoven fabric to be wrapped around the heat exchanger component, increasing the wrapping weight and making it difficult to distribute the polymeric water-absorbing material evenly. To achieve thermal insulation with a highly insulating resin foam, a method has been proposed for reinforcing both ends of a structure made of a resin foam with a synthetic resin sheet laminated to the surface, which is then wrapped around the heat exchanger pipe. However, even in thermal insulation cover members in which a nonwoven fabric is placed on the surface of such a foam and embossed instead of a synthetic resin sheet, condensation water may drip due to gravity when the vertical pipe is quite long or when the pipe is climbing over the beams or vertical walls of an apartment building or building. Dripping condensation water can lead to the growth of mold and fungi in the area where condensation water drips or in the vicinity of the dripping area, making the surrounding environment unsanitary. Therefore, the present invention aims to provide a thermal insulation cover member for preventing or suppressing condensation water dripping, which can suppress or prevent condensation water dripping on the surface of piping prone to condensation water dripping, such as vertical refrigerant pipes for air conditioners, or in duct covers. It also aims to provide other thermal insulation cover members for preventing or suppressing condensation water dripping, as well as heat exchanger pipe covering members and duct covering members, piping structures, duct covering structures, and electrical equipment box covering structures using these members. The nonwoven fabric for the thermal insulation cover member and a method for using the nonwoven fabric in the thermal insulation cover member, and a method for using the thermal insulation cover member in various covering members, including heat exchanger pipe covering members. In the present invention, the term "heat exchange piping covering member" refers to piping members such as joint covering members, elbow covering members, cheese covering members, covering members to be placed over existing conventional piping covers, etc. Note that the various covering members including the heat exchange piping covering member include not only heat exchange piping covering members but also duct covering members and electrical equipment box covering members.

[0010] In view of the above-mentioned object, the present invention has discovered that even in a severe operating environment where condensation water drips in practical piping, when a nonwoven fabric in which superabsorbent resin fibers are mixed with at least the thermoplastic resin fibers constituting the skeletal structure (preferably a nonwoven fabric that satisfies the water retention parameter specified in the present invention and the water retention capacity in a water retention test) is laminated to the surface of a polyethylene-based resin foam and used, condensation water is less likely to drip. Although the reason for this is not entirely clear, it is presumed that the insulating effect of the resin foam increases the surface temperature of the nonwoven fabric placed on the surface of the cover member, making condensation less likely, and that the incorporation of superabsorbent resin fibers into the nonwoven fabric not only increases water retention but also optimizes the diffusion and evaporation of water within the nonwoven fabric, leading to the above-mentioned excellent effect. The present invention was made based on this new finding, and has led to the development of a thermal insulating cover member for preventing or suppressing dripping of condensation water, a heat exchange piping cover member and a duct cover member, piping structures and duct cover structures using these, and electrical equipment box cover structures, as well as a nonwoven fabric used in the thermal insulating cover member and a method of using the nonwoven fabric for various cover members including the thermal insulating cover member. Here, the present invention has led to the development of methods of using the thermal insulating cover member as a heat exchange piping cover member for joints, elbow cover member, T-piece cover member, cover member to be placed over an existing conventional piping cover, duct cover member, electrical equipment box cover member, etc. That is, the present invention comprises the following means.

[0011] (1) A heat-insulating cover member for preventing or suppressing dripping of condensation water, comprising a resin foam having a nonwoven fabric disposed on the surface thereof, the resin foam being a polyethylene resin foam having closed cells, the nonwoven fabric being fixed to one surface of the resin foam by fusion or adhesive, the nonwoven fabric being made of a single layer of thermoplastic resin fibers mixed with a predetermined amount of superabsorbent resin fibers, and at least some of the thermoplastic resin fibers being fused or adhesively bonded to each other, the nonwoven fabric comprising 10% by mass to 80% by mass of the superabsorbent resin fibers, and the remainder comprising 20% ​​by mass to 90% by mass of the thermoplastic resin fibers. (2) The fiber diameter of the thermoplastic resin fibers used in the nonwoven fabric is in the range of 5 to 30 μm, the product thickness of the nonwoven fabric is 0.5 to 2.0 mm, and the basis weight of the nonwoven fabric is 30 to 300 g / m. ２(3) The heat-insulating cover member for preventing or suppressing dripping of condensation water according to (1), characterized in that the thermoplastic resin fiber that is the base resin fiber of the nonwoven fabric is made of a monofilament of polyethylene terephthalate, polyethylene, or polypropylene, or a core-sheath structure fiber of these, or a fiber in which any of these fibers is mixed with other fibers, the nonwoven fabric is such that at least some of the thermoplastic resin fibers are fused or bonded to each other, and the polyethylene-based resin foam contains a flame retardant. (4) The nonwoven fabric has a moisture retention parameter of 0.70 or more, which retains moisture against gravity, and the nonwoven fabric has a water retention capacity of 7.0 g or more, as determined under specified conditions. The moisture retention parameter is a parameter obtained by providing a mark line across the width of a strip-shaped test piece having dimensions of 200 mm length x 25 mm width at the midpoint in the longitudinal direction on the surface, dropping 400 μL of a colored test liquid onto the mark line while the test piece is held horizontally, and then holding the test piece vertically for 5 minutes immediately after dropping, and dividing the average value of the upward distance from the mark line of the test piece to the point where the test liquid reaches, in the width direction of the test piece, by the average value of the downward distance from the mark line of the test piece to the point where the test liquid reaches, which is an index value using the upward distance from the mark line of the test piece and the downward distance from the mark line of the test piece. The heat-insulating cover member for preventing or suppressing dripping of condensation water described in (1) is characterized in that the water retention capacity is determined by inserting a refrigerant pipe having a length of 150 mm and a diameter of 25 mm, the refrigerant pipe having the heat-insulating cover member attached thereto, into a container containing 20 g of water, and then maintaining the container in a thermo-hygrostat at a temperature of 23°C and a humidity of 30% for 6 hours, removing the container, and removing the water from the container. In (1), the nonwoven fabric used in the invention contains 10% to 80% by mass of superabsorbent resin fibers, which enables prevention or suppression of dripping of condensation water. Furthermore, the nonwoven fabric contains 20% to 90% by mass of thermoplastic resin fibers, which allows the nonwoven fabric to diffuse and evaporate absorbed water, while ensuring the mechanical strength of the nonwoven fabric containing the superabsorbent resin fibers and the fusion or adhesive strength with a resin foam.

[0012] (5) A heat-insulating cover member for preventing or suppressing dripping of condensation water, in which a nonwoven fabric is arranged on the surface of a resin foam, the resin foam being a polyethylene resin foam having closed cells, and the nonwoven fabric being fixed to one surface of the resin foam by fusion or adhesion, the nonwoven fabric being a laminated nonwoven fabric having a two-layer laminated structure, the first layer of the nonwoven fabric being composed only of thermoplastic resin fibers, at least some of the thermoplastic resin fibers being fused or adhered to each other, the second layer of the nonwoven fabric being composed of a nonwoven fabric in which a predetermined amount of superabsorbent resin fibers is mixed with thermoplastic resin fibers, at least some of the thermoplastic resin fibers being fused or adhered to each other, the nonwoven fabric of the second layer containing 10% by mass or more and 80% by mass or less of superabsorbent resin fibers relative to the total mass of the nonwoven fabric constituting the second layer, and the remainder being 20% ​​by mass or more and 90% by mass or less of the thermoplastic resin fibers, and either the first layer or the second layer of the nonwoven fabric being joined to the surface of the resin foam. (6) A heat-insulating cover member for preventing or suppressing dripping of condensation water, characterized in that the total thickness of the first and second layers of the nonwoven fabric is 0.5 to 2.0 mm, and the total basis weight of the first and second layers is 30 to 300 g / m ２ The heat-insulating cover member for preventing or suppressing dripping of condensation water according to (5), characterized in that the thickness and basis weight of the nonwoven fabric of the first layer are smaller than the thickness and basis weight of the nonwoven fabric of the second layer, and the fiber diameter of the thermoplastic resin fiber used in the nonwoven fabric of the first or second layer is in the range of 5 to 30 μm. (7) The total thickness of the first and second layers of nonwoven fabric is 0.5 to 2.0 mm, and the total basis weight of the first and second layers is 30 to 300 g / m. ２ The thickness of the nonwoven fabric of the first layer is 0.1 to 0.5 mm, and the basis weight of the first layer is 5 to 50 g / m ２ and the weight of the second layer is 25 to 250 g / m ２(8) The heat-insulating cover member for preventing or suppressing dripping of condensation water according to (5), characterized in that the thickness and basis weight of the nonwoven fabric of the first layer are smaller than those of the nonwoven fabric of the second layer, the fiber diameter of the thermoplastic resin fibers used in the nonwoven fabric of the first or second layer is in the range of 5 to 30 μm. (9) The heat-insulating cover member for preventing or suppressing dripping of condensation water according to (7), characterized in that the thermoplastic resin fibers serving as the base resin fibers of the nonwoven fabric are monofilaments of polyethylene terephthalate, polyethylene, or polypropylene, or core-sheath fibers thereof, or fibers obtained by mixing any of these fibers with other fibers, at least some of the thermoplastic resin fibers in the nonwoven fabric are fused or bonded to each other, and the polyethylene-based resin foam contains a flame retardant. Here, in (5), if the nonwoven fabric forming the second layer used in the invention contains 10% by mass or more and 80% by mass or less of superabsorbent resin fibers relative to the total mass of the nonwoven fabric constituting the second layer, it becomes possible to prevent or suppress dripping of condensation water, and if the nonwoven fabric further contains 20% by mass or more and 90% by mass or less of thermoplastic resin fibers, it is possible to diffuse and evaporate the moisture absorbed by the nonwoven fabric in the second layer, and to ensure the mechanical strength of the nonwoven fabric of the second layer and the fusion or adhesive strength with the resin foam.

[0013] (9) The nonwoven fabric has a moisture retention parameter of 0.70 or more, which retains moisture against gravity, and the nonwoven fabric has a moisture retention capacity of 7.0 g or more, as determined under specified conditions. The moisture retention parameter is a parameter obtained by providing a mark line across the width of a strip-shaped test piece having dimensions of 200 mm length x 25 mm width at the midpoint in the longitudinal direction on the surface, dropping 400 μL of a colored test liquid onto the mark line while the test piece is held horizontally, and then holding the test piece vertically for 5 minutes immediately after dropping, and dividing the average value of the upward distance from the mark line of the test piece to the point where the test liquid reaches, in the width direction of the test piece, by the average value of the downward distance from the mark line of the test piece to the point where the test liquid reaches, which is an index value using the upward distance from the mark line of the test piece and the downward distance from the mark line of the test piece. Furthermore, the heat-insulating cover member for preventing or suppressing dripping of condensation water (5) is characterized in that the water retention capacity is determined by inserting a refrigerant pipe having a length of 150 mm and a diameter of 25 mm, with the heat-insulating cover member attached to the outer periphery thereof, into a container containing 20 g of water, and then retaining the container in a thermo-humidistat bath at a temperature of 23°C and a humidity of 30% for 6 hours, after which the container is removed and the water is removed, and the water retention capacity is determined from the mass after removal of the water. (10) A joint covering member that can be arranged to cover the gap between an insulating cover member for preventing or suppressing dripping of condensation water described in any one of (1) to (9) when the piping is covered with the insulating cover member for preventing or suppressing dripping of condensation water and an insulating cover member arranged adjacent to the insulating cover member in the longitudinal direction of the piping, wherein the joint covering member has a release paper attached to the adhesive on one side of a foam and a nonwoven fabric attached to the other side of the foam, and the adhesive layer is attached to the outer periphery of the insulating cover member with the surface of the nonwoven fabric attached to the foam forming the outer periphery, making it possible to use the joint covering member at the joint of the cover member to prevent or suppress dripping of condensation water.(11) An elbow covering member characterized by being capable of preventing or suppressing dripping of condensation water by covering the elbow portion of the 90° bend or the vicinity of the 90° bend formed by directly bending the piping by 90°, with the surface of the member attached to the nonwoven fabric foam as the outer surface, which can be obtained by folding the heat-insulating cover member for preventing or suppressing dripping of condensation water described in any one of (1) to (9) opposite to each other in a shape back to back of a predetermined size so as to be able to cover the 90° bend portion of the piping, and by covering the elbow portion of the 90° bend portion or the vicinity of the 90° bend portion formed by directly bending the piping by 90°. (12) The cheese member is a metal piping member that branches downward or upward from a portion corresponding to the linear head portion of a T-shape, and has a branch portion that branches downward or upward with the T-shaped head portion as a bending portion so that the cheese member can be covered with a heat-insulating cover member for preventing or suppressing dripping of condensation water described in any one of (1) to (9). When the bending portion is bent using the bending portion as a hinge starting point for opening, the bending portion and the branch portion surround the entire cheese member, forming a cheese member covering structure that can prevent or suppress dripping of condensation water. (13) A covering member for covering an existing conventional piping cover, characterized in that the covering member for covering an existing piping having a polyethylene film attached to its surface is wrapped around a heat exchanger piping in a substantially cylindrical shape so that both ends face each other at the center, and the heat-insulating covering member is further wrapped around the outer surface of the covering member for covering the existing conventional piping cover so that both ends face each other with the nonwoven fabric surface as the outer surface, thereby preventing or suppressing dripping of condensation water. (14) A duct covering member characterized in that the outer surface of a duct can be covered with the heat-insulating covering member for preventing or suppressing dripping of condensation water according to any one of (1) to (9).(15) In a piping structure including at least any one of horizontal piping, oblique piping, vertical piping, and curved piping, in which a heat-insulating cover member for preventing or suppressing dripping of condensation water according to any one of (1) to (9) is covered on the outer periphery of the refrigerant piping, the piping structure is characterized in that the heat-insulating cover member for preventing or suppressing dripping of condensation water has the surface of the single-layer nonwoven fabric or the surface of either the first layer or the second layer of a laminated nonwoven fabric as its outer surface, and the refrigerant piping is covered with each of the heat-insulating cover members. (16) In a piping structure including at least any one of horizontal piping, oblique piping, vertical piping, and bent piping in a glasses-shaped cross section piping in which the heat-insulating cover member for preventing or suppressing dripping of condensation water according to any one of (1) to (9) is coated on the outer periphery of each of the two refrigerant pipes, and the heat-insulating cover members are heat-sealed or bonded to each other, the outer periphery of each refrigerant pipe of the piping structure is coated with the surface of the single-layer nonwoven fabric or the surface of the first layer or second layer of the laminated nonwoven fabric of the heat-insulating cover member for preventing or suppressing dripping of condensation water, and the two refrigerant pipes are arranged opposite each other and the outer surfaces of the nonwoven fabrics are heat-sealed or bonded to each other, thereby integrating the two pipes into a glasses-shaped piping structure. (17) In a piping structure including at least one of horizontal piping, diagonal piping, vertical piping, and bent piping, in which one or more refrigerant pipes, drain pipes, and wiring or wiring pipes are provided, and the one or more refrigerant pipes, drain pipes, and wiring or wiring pipes are stored inside a thermally insulated cover member for preventing or suppressing dripping of condensation water described in any of (1) to (9), the surface of the single-layer nonwoven fabric or the surface of the first layer or second layer of a laminated nonwoven fabric is used as the outer surface, and the thermally insulated cover member for preventing or suppressing dripping of condensation water has an outer peripheral surface shape that is approximately cylindrical in cross section, surrounding the refrigerant pipes, drain pipes, and wiring or wiring pipes so that they can be stored inside the thermally insulated cover member for preventing or suppressing dripping of condensation water, thereby storing components to be installed inside the thermally insulated cover member for preventing or suppressing dripping of condensation water.In this way, the wiring may be inside the piping, or the wiring may be exposed and disposed inside the piping structure.

[0014] (18) A covering structure using a heat-insulating cover member for preventing or suppressing dripping of condensation water in a duct for a heat exchanger, characterized in that the entire outer surface of an iron duct for a heat exchanger having a substantially rectangular cross section is covered with the heat-insulating cover member for preventing or suppressing dripping of condensation water according to any one of (1) to (9) so as to cover the entire outer surface of the iron duct for a heat exchanger. (19) A covering structure for an electric equipment box that receives power from an external power source and distributes the received power to necessary equipment, characterized in that the heat-insulating cover member for preventing or suppressing dripping of condensation water according to any one of (1) to (9) is disposed at least on an inner peripheral surface including a ceiling surface of the electric equipment box, or on the back or front surface of the electric distribution panel excluding an opening in the electric distribution panel. (20) The nonwoven fabric is made of a nonwoven fabric containing a predetermined amount of superabsorbent resin fibers in thermoplastic resin fibers, and the nonwoven fabric has a water retention parameter of 0.70 or more, which retains water against gravity, and a water retention capacity determined under predetermined conditions of 7.0 g or more, and the product thickness of the nonwoven fabric is 0.5 to 2.0 mm, and the basis weight of the nonwoven fabric is 30 to 300 g / m ２wherein the nonwoven fabric is made by mixing a predetermined amount of superabsorbent resin fibers with thermoplastic resin fibers having a fiber diameter in the range of 5 to 30 μm, at least a portion of which is fused or bonded to each other, and the nonwoven fabric contains 10% by mass or more and 80% by mass or less of superabsorbent resin fibers relative to the total mass of the nonwoven fabric, with the remainder being 20% ​​by mass or more and 90% by mass or less of the thermoplastic resin fibers, and the holding power parameter is measured by providing a mark line across the width direction on the surface of a strip-shaped test piece having dimensions of 200 mm length x 25 mm width at a midpoint in the longitudinal direction, and dropping 400 μL of a colored test liquid onto the mark line while the test piece is held horizontally, and then immediately after dropping, holding the test piece vertically for 5 minutes, the parameter is obtained by dividing the average value of the ascending distance from the marked line of the test piece to the point where the test liquid reaches above the marked line of the test piece in the width direction of the test piece, which is an index value using the ascending distance from the marked line of the test piece and the descending distance from the marked line of the test piece, by the average value of the descending distance from the marked line of the test piece to the point where the test liquid reaches below the marked line of the test piece in the width direction; and further, the water retention capacity is the water retention capacity obtained by inserting a refrigerant pipe having a length of 150 mm and a diameter of 25 mm, with the thermal insulation cover member attached to the outer periphery of the refrigerant pipe, into a container containing 20 g of water, and then retaining the container in a thermo-hygrostat at a temperature of 23°C and a humidity of 30% for 6 hours, removing the container, and then removing the water from the container, and determining the water retention capacity from the mass after the water removal.

[0015] (21) A nonwoven fabric is made of a nonwoven fabric containing a predetermined amount of superabsorbent resin fibers in thermoplastic resin fibers, and the nonwoven fabric has a water retention parameter of 0.70 or more for retaining water against gravity, and a water retention capacity determined under predetermined conditions of 7.0 g or more, and the nonwoven fabric is a laminated structure nonwoven fabric having a laminated structure consisting of a first layer and a second layer of nonwoven fabric, and the thickness of the entire nonwoven fabric is 0.5 to 2.0 mm, and the basis weight of the entire nonwoven fabric is 30 to 300 g / m ２ Furthermore, the thickness of the nonwoven fabric of the first layer is 0.1 to 0.5 mm, and the basis weight of the nonwoven fabric of the first layer is 5 to 50 g / m ２the thickness and basis weight of the nonwoven fabric of the first layer are smaller than the thickness and basis weight of the nonwoven fabric of the second layer, the first layer of the nonwoven fabric is composed only of thermoplastic resin fibers having a fiber diameter in the range of 5 to 30 μm and at least a portion of which is fused or bonded to each other, and the nonwoven fabric constituting the second layer uses the same thermoplastic resin fibers as the first layer as base fibers, and the nonwoven fabric of the second layer is composed of a nonwoven fabric in which a predetermined amount of superabsorbent resin fibers is mixed with base resin fibers which are thermoplastic resin fibers having a fiber diameter in the range of 5 to 30 μm and at least a portion of which is fused or bonded to each other, and the nonwoven fabric constituting the second layer is a nonwoven fabric containing 10% by mass or more to 80% by mass of superabsorbent resin fibers with respect to the total mass of the fibers of the nonwoven fabric of the second layer, and the remainder being 20% ​​by mass or more to 90% by mass of the thermoplastic resin fibers, and the holding power parameter is a marking line is provided across the surface of a strip-shaped test specimen having a length of 200 mm and a width of 25 mm at the midpoint in the longitudinal direction, 400 μL of colored test liquid is dropped on the marking line while the test specimen is held horizontally, and the test specimen is then held vertically for 5 minutes immediately after the dropping; the parameter is calculated by dividing the average value of the upward distance from the marking line on the test specimen to the point where the test liquid reaches, in the width direction, of the test specimen, which is an index value using the upward distance from the marking line on the test specimen and the downward distance from the marking line on the test specimen, by the average value of the downward distance from the marking line on the test specimen to the point where the test liquid reaches, in the width direction; and the water retention capacity is calculated by inserting a refrigerant pipe having a length of 150 mm and a diameter of 25 mm, with the heat-insulating cover member attached to the outer periphery of the refrigerant pipe, into a container containing 20 g of water, holding the refrigerant pipe in a thermo-humidistat chamber at a temperature of 23° C. and a humidity of 30% for 6 hours, and then removing the container and determining the water retention capacity from the mass after water removal. (22) The nonwoven fabric used for a heat-insulating cover member for preventing or suppressing dripping of condensation water according to (20) or (21), characterized in that the thermoplastic resin fibers are either monofilaments of polyethylene terephthalate, polyethylene, or polypropylene, or core-sheath fibers thereof, or fibers in which any of these fibers is mixed with other thermoplastic resin fibers, and at least some of these resin fibers are fused or bonded to each other.(23) A method for using the laminated nonwoven fabric according to (20) or (21) as a heat-insulating cover member for preventing or suppressing dripping of condensation water, in which the resin foam is bonded to the surface of a polyethylene-based resin foam having closed cells, characterized in that the surface of the single-layer nonwoven fabric or either the first layer or the second layer of the laminated nonwoven fabric is facing outward, and the remaining layer of the layer facing outward is used as the bonding surface, and the nonwoven fabric and the resin foam are bonded to one surface of the resin foam so as to be fixed by fusion or adhesive. (24) A method for using a heat-insulating cover member for preventing or suppressing dripping of condensation water as described in any one of (1) to (9) for various covering members including heat exchanger piping covering members, characterized in that the heat-insulating cover member for preventing or suppressing dripping of condensation water described in any one of (1) to (9) is used as a covering member for joints used in gaps between heat-insulating cover members, an elbow covering member, a cheese member covering member, a covering member for covering an existing conventional piping cover, a duct covering member, or an electrical equipment box covering member.

[0016] The thermal insulation cover member for preventing or suppressing dripping of condensation water of the present invention can suppress or prevent dripping of condensation water even in vertical piping for refrigerant such as air conditioners, which is prone to dripping of condensation water. The effects of the present invention can be achieved by optimizing both the moisture reduction effect due to evaporation of condensation water, which occurs when moisture absorbed in the superabsorbent resin fibers of the nonwoven fabric diffuses and evaporates against the influence of gravity, and the water retention effect of the superabsorbent resin fibers mixed into the skeletal structural fibers. As a result, the thermal insulation cover member of the present invention, as well as other heat exchanger piping covering members and duct covering members, piping structures and duct covering structures using these, electrical equipment box covering structures, nonwoven fabrics used in the thermal insulation cover member and methods of using the nonwoven fabric for the thermal insulation cover member, and methods of using the thermal insulation cover member for various covering members, including heat exchanger piping covering members, can be obtained.

[0017] FIG. 1A is a partially cutaway perspective view schematically showing a piping structure (single pipe) 10 according to a preferred embodiment of the present invention. It is a sectional view taken along the line X-X of FIG. 1A (b). FIG. 2A is a partially cutaway perspective view schematically showing a piping structure (goggle-shaped pipe) 20 according to another preferred embodiment of the present invention. It is a sectional view taken along the line Y-Y of FIG. 2A (b). FIG. 3 is a sectional view schematically showing a piping structure 30 having a two-layer non-woven fabric layer according to yet another preferred embodiment of the present invention. FIG. 4 is an enlarged sectional view schematically showing (particularly exaggerating the structure of fibers and bubbles) the internal structure of the drip-preventing or drip-suppressing heat-insulating cover member of the embodiment shown in FIG. 1A. FIG. 5 is an enlarged sectional view schematically showing (particularly exaggerating the structure of fibers and bubbles) the internal structure of the drip-preventing or drip-suppressing heat-insulating cover member of the embodiment having a two-layer non-woven fabric shown in FIG. 3, and (a) shows an aspect in which a highly water-absorbent resin fiber is included in the inner layer. FIG. 6 is an enlarged sectional view schematically showing (particularly exaggerating the structure of fibers and bubbles) the internal structure of the drip-preventing or drip-suppressing heat-insulating cover member according to a modified example of the embodiment having a two-layer non-woven fabric shown in FIG. 3, and (b) shows an aspect in which a highly water-absorbent resin fiber is included in the outer layer. FIG. 7 is a sectional view schematically showing a piping structure 40 (piping including refrigerant piping, drain piping, and electric wire piping) according to yet another preferred embodiment of the present invention. FIG. 8 is a front view schematically showing a measuring instrument for the holding force parameter. FIG. 9 is a sectional view schematically showing a water retention measuring test body and apparatus. FIG. 10 is a sectional view schematically showing the state in which water evaporates from the water retention measuring test body. FIG. 11 is a piping configuration diagram schematically showing a drip confirmation test of condensed water under severe environmental conditions by a vertical pipe using a goggle-shaped pipe of a test material. FIG. 12 is a sectional view schematically showing a joint covering member to which a release sheet is applied. FIG. 13 is a perspective view schematically showing a state in which the joint of the protective member generated at the joint of the piping structure is covered with the joint covering member. FIG. 14 is a front view schematically showing a state in which an elbow covering member (bend joint) used for a 90° bend portion of the piping is developed. FIG. 15 is a front view schematically showing a state in which a cheese covering member used for a T-branch portion of the piping is developed. FIG. 16 is a sectional view schematically showing an aspect when a covering member to be put on an existing conventional piping cover is attached to the conventional piping cover. FIG. 17 is a sectional view schematically showing a state in which a duct covering member is attached to the outer peripheral surface of an iron duct. FIG. 18 is a drawing showing a situation where a heat-insulating cover member is laid on the inner surface of a distribution box as an example of an electric equipment box.This figure shows the change over time in the amount of condensation water dripping in a condensation water drip test using a vertical pipe with an eyeglass-type pipe for a representative example of a test material in a harsh environment of a temperature of 35°C and a humidity of 90%.

[0018] An embodiment of the present invention will be described in detail below. FIG. 1A is a partially cutaway perspective view schematically illustrating a piping structure 10 equipped with a heat-insulating cover member 5 for preventing or suppressing dripping of condensed water according to a preferred embodiment of the present invention. FIG. 1B is a cross-sectional view taken along the arrows X-X in FIG. 1A. The heat-insulating cover member 5 for preventing or suppressing dripping according to this embodiment has a structure in which a nonwoven fabric 3 is disposed on the surface of a resin foam 2 covering a refrigerant pipe 1 containing a cavity (flow path) 6, thereby suppressing or preventing dripping of condensed water condensed on the surface of the nonwoven fabric. The resin foam 2 is a polyethylene resin foam having closed cells. The nonwoven fabric 3 is fixed to one surface of the resin foam 2 by fusion or adhesive bonding. Hereinafter, the terms "diffusive evaporation" and "diffusive transpiration" will be used, but these terms are interpreted as essentially synonymous in the present invention.

[0019] [Various Parameters] In the drip-preventing or drip-suppressing heat-insulating cover member 5 of this embodiment, the nonwoven fabric 3 contains superabsorbent resin fibers in an amount of 10% by mass to 80% by mass, preferably 15% by mass to 75% by mass, and more preferably 25% by mass to 75% by mass. If the content of superabsorbent resin fibers is below the above-mentioned lower limit, the ability to prevent or suppress dripping of condensation water will be poor. If the content of superabsorbent resin fibers is above the above-mentioned upper limit, the bonding strength and shape stability of the nonwoven fabric will be poor. Note that when the nonwoven fabric is composed of multiple layers, the blending amount (mixing ratio) is within the above-mentioned range in the layer containing the superabsorbent resin fibers.

[0020] The average fiber diameter of the substrate fibers of the nonwoven fabric used in the present invention is preferably in the range of 5 to 30 μm, and fibers in this range are often used for nonwoven fabrics. The reason for this is that if the fiber diameter is below the lower limit, the strength of the nonwoven fabric is insufficient, which tends to reduce the durability of the protective member surface during use. Furthermore, if the fiber diameter exceeds the upper limit, the increased diameter of the nonwoven fabric tends to result in a loss of stability in the entanglement and fusion structure of the substrate resin. Therefore, the average fiber diameter is preferably in the range of 10 to 25 μm or 12 to 23 μm. More preferably, it is 15 to 20 μm. For the test materials in the examples described below, the measured fiber diameter of each test material is referred to as fiber diameter for simplicity, but these measured fiber diameters refer to the average fiber diameter. The fiber diameter of the substrate fibers (thermoplastic resin fibers) of the nonwoven fabric specified here (excluding the superabsorbent resin fibers described below) also applies to the fiber diameters of the first and second layers of a two-layer nonwoven fabric, and the preferred range also refers to the average fiber diameter. The superabsorbent resin fibers used in the present invention may have a larger fiber diameter than the thermoplastic resin fibers. However, if the fiber diameter of the superabsorbent resin fibers is too large, the amount of expansion of the superabsorbent resin fibers will be too great, causing the nonwoven fabric structure of the base resin to become unstable and resulting in uneven absorption of water within the nonwoven fabric. To avoid this problem, it is desirable that the maximum diameter of the superabsorbent resin fibers be 100 μm or less, and that the ratio of the diameter of the superabsorbent resin fibers to the thermoplastic resin fibers be 4 times or less. It is even more desirable that the maximum diameter of the superabsorbent resin fibers be 80 μm or less, and that the ratio of the diameter of the superabsorbent resin fibers to the thermoplastic resin fibers be 3 times or less.

[0021] In the heat-insulating cover member 5 for preventing or suppressing dripping of condensation water according to this embodiment, the product thickness of the nonwoven fabric 3 is preferably 0.5 to 2.0 mm, more preferably 0.6 to 1.6 mm, and even more preferably 0.7 to 1.4 mm. When the nonwoven fabric 3 is a laminate of two or more layers, the total thickness thereof is preferably within the above range. If the nonwoven fabric thickness is below the above lower limit, the base resin fiber will not be able to stably hold the superabsorbent resin fiber. On the other hand, if the product thickness exceeds the above upper limit, the shape stability of the nonwoven fabric after water absorption will decrease. When the nonwoven fabric is composed of two layers, the total product thickness of the nonwoven fabric 3 for the two layers is preferably within the above range. Distinguishing the two layers, the first layer (the layer not containing the superabsorbent resin fiber) is preferably 0.05 to 0.6 mm, more preferably 0.1 to 0.5 mm, and even more preferably 0.2 to 0.4 mm. The product thickness of the second layer (the layer containing the superabsorbent polymer fiber) is preferably 0.3 to 1.5 mm, more preferably 0.4 to 1.2 mm, and even more preferably 0.5 to 1.0 mm. Relatively speaking, it is preferable that the thickness of the first layer is smaller than the thickness of the second layer.

[0022] The weight of the nonwoven fabric 3 is 30 g / m ２ It is preferable that the weight is 35 g / m or more. ２ More preferably, it is 40 g / m or more. ２ The upper limit is preferably 300 g / m or more. ２ It is preferable that the weight is 250 g / m or less. ２ More preferably, it is 200 g / m or less. ２ More preferably, it is 150 g / m or less. ２ When the nonwoven fabric 3 is composed of two layers, the weight of the second layer (the layer containing the highly water-absorbent polymer fiber) is preferably 10 to 250 g / m or less. ２ and 15 to 200 g / m ２ It is preferable that the density is 15 to 150 g / m ２ More preferably, it is 20 to 150 g / m ２ The weight of the first layer (the layer not containing the highly water-absorbent polymer fiber) is more preferably 5 to 50 g / m ２and 10 to 30 g / m ２ It is preferable that the density is 15 to 25 g / m ２ It is more preferable that the nonwoven fabric 3 is a laminate of two or more layers, the total basis weight is preferably within the above range. In the present invention, if the basis weight of the nonwoven fabric is less than the above lower limit, sufficient water retention cannot be ensured. On the other hand, if the basis weight exceeds the above upper limit, it will affect the fusion properties of the fused portion after water absorption, the shape of the nonwoven fabric after water absorption will become unstable, and moldability will be reduced. The upper and lower limits of the second layer containing superabsorbent resin fibers when the nonwoven fabric is formed in two layers are also determined for the same reason. Here, since the first layer is a layer that promotes the transpiration effect by diffusion and evaporation of absorbed moisture, the basis weight does not need to be as large as that of the second layer, and it is desirable that the basis weight of the first layer be smaller than that of the second layer, as long as it is within the above range. Furthermore, in the case of Lanseal, the basis weight of the single-layer product and the laminate product was intentionally increased to understand the characteristics of the nonwoven fabric of the laminate when the basis weight of the second layer was high. However, as can be seen in other cases, the total basis weight can be reduced in the case of laminate products. In the case of a single-layer nonwoven fabric, the content of the highly water-absorbent resin fiber in the nonwoven fabric is 10% to 80%, and the content of the base resin fiber is 20% to 90%. ２ In this case, the weight of the highly absorbent resin fiber is 30 to 240 g / m ２ The remainder is the weight of the base resin fiber, and the weight of the nonwoven fabric is 200 g / m ２ In this case, the weight of the highly absorbent resin fiber is 20 to 160 g / m ２ The remainder is the weight of the base resin fiber, and the weight of the nonwoven fabric is 150 g / m ２ In this case, the weight of the highly absorbent resin fiber is 15 to 120 g / m ２ The weight of the nonwoven fabric is 50 g / m², and the rest is the weight of the base resin fiber. ２ In this case, the weight of the highly absorbent resin fiber is 5 to 40 g / m ２The remainder is the basis weight of the base resin fiber. Considering the relationship between the blending ratio of the superabsorbent resin fiber in the nonwoven fabric and the amount of condensation water dripping (described later), a blending ratio of 25% or more improves the amount of condensation water dripping by more than 50%, so a blending ratio of 25% or more is preferred. Since a further increase in the blending ratio can reduce the amount of condensation water dripping, a blending ratio of 30% or more is preferred, but considering the cost of the nonwoven fabric, the upper limit may be set to 60% or less.

[0023] The fiber diameter of the superabsorbent resin fibers mixed into the nonwoven fabric 3 is not particularly limited, but is preferably larger than the fiber diameter of the thermoplastic resin fibers that make up the nonwoven fabric. Specifically, the fiber diameter of the superabsorbent resin fibers is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more. The upper limit is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 50 μm or less.

[0024] In the heat-insulating cover member 5 for preventing or suppressing dripping of condensation water according to this embodiment, the moisture retention parameter for retaining moisture against gravity of the nonwoven fabric 3 is preferably 0.70 or more, more preferably 0.80 or more, and even more preferably 1.00 or more. While no upper limit is specifically set, due to the nature of the parameter for retaining moisture against gravity, it is practically difficult for it to exceed 1.3, and it is considered that the maximum is 1.3 or less. By making this moisture retention parameter equal to or greater than the above-mentioned lower limit, the effect of improving the diffusion function and transpiration function can be expected.

[0025] In the heat-insulating cover member 5 for preventing or suppressing dripping of condensation water according to this embodiment, the water retention capacity of the nonwoven fabric 3 in a water retention test is preferably 7.0 g or more, more preferably 7.5 g or more, even more preferably 8.0 g or more, even more preferably 8.5 g or more, and even more preferably 9.0 g or more. It is estimated that the upper limit is likely to be 20 g or less, even taking into account the amount of water injected and water absorption from the test environment. When this water retention capacity is equal to or greater than the lower limit, the water retention function is improved, and the effect of preventing or suppressing dripping of condensation water can be expected. Here, since the nonwoven fabric of the present invention is expected to achieve a synergistic effect between the water retention parameter and water retention, it is necessary for the water retention parameter to be 0.70 or more and the water retention capacity in an evaporative environment to be 7.0 g or more, and it is particularly preferable for both to be satisfied.

[0026] FIG. 2A is a partially cutaway perspective view schematically illustrating a piping structure 20 including a heat-insulating cover member 5 for preventing or suppressing dripping of condensation water according to another preferred embodiment of the present invention. FIG. 2B is a cross-sectional view taken along the line Y-Y. The piping structure 20 of this embodiment has two pipes (refrigerant pipes 1 each containing a cavity (flow path) 6) connected together, forming a glasses-shaped piping structure in cross section (see FIG. 2B). The pipes may be connected by thermal fusion of the nonwoven fabric 3 as shown, or a resin foam 2 may be partially thermally fused to form a strong connection structure. In this embodiment, the parameters of the thermoplastic resin fibers constituting the nonwoven fabric 3 and the amount and fiber diameter of the superabsorbent resin fibers mixed therein are the same as those defined in the embodiment according to FIG. 1A, and the preferred ranges are also the same.

[0027] 3 is a cross-sectional view schematically illustrating a piping structure 30 including a heat-insulating cover member 5 for preventing or suppressing dripping of condensation water according to yet another preferred embodiment of the present invention. In this embodiment, the nonwoven fabric 3 constituting the heat-insulating cover member 5 for preventing or suppressing dripping of condensation water has a two-layer structure consisting of a first layer 31 and a second layer 32. In this embodiment, the parameters such as the amount and fiber diameter of the superabsorbent polymer fibers mixed in the nonwoven fabric 3 are the same as those defined in the embodiment of FIG. 1A , and the preferred ranges are also the same. Note that the preferred ranges for the thickness and basis weight of the nonwoven fabric for the first and second layers are as already described above in the section [Various Parameters].

[0028] 4 is an enlarged cross-sectional view showing a schematic internal structure of the heat-insulating cover member 5 for preventing or suppressing dripping of condensation water according to the embodiment shown in FIG. 1A. This figure merely shows a schematic microscopic structure, and the actual product in the present invention may not completely match the one shown. In this embodiment, as shown in the figure, thermoplastic resin fibers 35 constituting the nonwoven fabric 3 and highly water-absorbent resin fibers 36 mixed therewith are used. The thermoplastic resin fibers 35 may have a fiber structure in which they are mutually entangled and partially fused or bonded.

[0029] FIG. 5A is an enlarged cross-sectional view schematically illustrating the internal structure of the drip-preventing or drip-suppressing heat-insulating cover member 5 according to the embodiment shown in FIG. 3 . In this embodiment, any adhesive structure may be used between the first layer 31 and the second layer 32, and the thermoplastic resin fibers 35 may be intertwined with each other or partially heat-fused or bonded. The embodiment shown in FIG. 5A illustrates an example in which the second layer 32 contains superabsorbent resin fibers 36 and is disposed as the lower layer. The embodiment shown in FIG. 5B illustrates an example in which the nonwoven fabric shown in FIG. 5A is inverted. That is, in FIG. 5B , the second layer 32 contains superabsorbent resin fibers 36 and is disposed as the upper layer. Although not particularly limited in the present invention, a preferred embodiment ( FIG. 5A ) is one in which the outer layer (first layer) 31 does not contain superabsorbent resin fibers and the inner layer (second layer) contains superabsorbent resin fibers.

[0030] [Resin Foam] In the present invention, the resin foam 2 contains independent cells 21 (FIGS. 4, 5A, and 5B). In the present invention, the resin foam 2 is a polyethylene-based resin foam. That is, the resin used for the resin foam 2 can be a polyethylene resin such as low-density polyethylene (LDPE) or high-density polyethylene (HDPE) alone, or a mixed resin of low-density polyethylene and high-density polyethylene. Furthermore, these polyethylene-based resin foams can be imparted with heat resistance or flame retardancy as needed. When a mixed resin of low-density polyethylene and high-density polyethylene is used, the low-density polyethylene and high-density polyethylene can be mixed in a predetermined ratio, for example, 40 parts by mass of low-density polyethylene to 60 parts by mass of high-density polyethylene. In addition to low-density polyethylene and high-density polyethylene, modified polyethylene resins such as vinyl acetate copolymer polyethylene (EVA) can also be used as the polyethylene-based resin. The reason for using vinyl acetate copolymer polyethylene instead of polyethylene is that it has high flexibility and elasticity, allowing it to be used in a variety of product applications. For example, F120N manufactured by Ube Maruzen Polyethylene Co., Ltd. can be used as low-density polyethylene, HD1300 manufactured by Japan Polyethylene Co., Ltd. can be used as high-density polyethylene, and DQDJ-1868 manufactured by ENEO SNUC Corporation can be used as vinyl acetate copolymer polyethylene.

[0031] Furthermore, when the flame retardancy of the foam is improved, a flame retardant is added. For 100 parts by mass of the resin, a predetermined amount of an antimony-based flame retardant, such as antimony trioxide, magnesium hydroxide, or aluminum hydroxide, a hydroxide-based flame retardant, or a bromine-based flame retardant can be added. In addition to the antimony-based flame retardant, bromine-based flame retardant, or hydroxide-based flame retardant, an inorganic filler may also be added. Furthermore, when heat resistance is to be imparted, carbon or titanium oxide may also be added within a predetermined range. In addition to the above, predetermined amounts of inorganic fillers, antioxidants, and stabilizers may also be added as needed.

[0032] For example, when flame retardants are added, the amount of flame retardant added must be 100 parts by mass or less in total, because if it exceeds 100 parts by mass, the effect will saturate and foaming properties will be inhibited. Here, the preferred amounts of antimony-based flame retardants and bromine-based flame retardants are each 20 parts by mass or less, and the preferred amount of hydroxide-based flame retardants is 80 parts by mass or less. Note that, since all flame retardants have a higher specific gravity than the resin component, when converted to a volumetric mixing ratio, the mixing ratio relative to the resin component is significantly smaller than the mass ratio, so there is no particular problem as long as the amount added is within the above range.

[0033] Here, a method for producing a polyethylene-based resin foam will be described using low-density polyethylene as the base resin. First, an organic decomposition-type foaming agent and a crosslinking agent are blended with low-density polyethylene as the base resin, and the resulting mixture is kneaded and pelletized in a pressure kneader to obtain pellets of a foamable resin composition. The pellets thus obtained are fed into the hopper of a single-screw extruder and extruded through a die of a predetermined width to obtain a foamable base sheet of a predetermined thickness.

[0034] Following the heating and extrusion of the foaming base sheet, the resin foam is continuously heated in a heating furnace to expand to a predetermined expansion ratio, and then passed through rolls to adjust the dimensions and surface properties of the foam, after which it is cut to a predetermined width according to the diameter of the pipe to be wrapped around.

[0035] The expansion ratio must be controlled taking into account thermal insulation and cushioning properties. Furthermore, when embossing, if the expansion ratio is too high, it becomes difficult to stably and uniformly emboss the nonwoven fabric after lamination. If the expansion ratio is too low, the resin becomes too rigid, making it difficult to obtain the desired embossing height and resulting in reduced thermal insulation. Therefore, the expansion ratio of the resin foam is preferably 20 to 40 times, and within this range, no particular problems arise. Regarding cushioning properties, an expansion ratio in the range of 20 to 40 times does not pose any particular problems. Although the thickness of the resin foam can be 15 mm or 20 mm, 10 mm is typically used. This is because a thicker resin foam reduces moldability, such as the bending processability of the heat exchanger piping after the cover member is attached, and the increased cross-sectional area of ​​the product reduces workability during piping installation. Taking these factors into consideration, a resin foam with a thickness of 10 mm is often used as a cover member.

[0036] In this embodiment, the nonwoven fabric is fixed to one surface of a resin foam by fusion or adhesive bonding, and the other surface of the resin foam is wrapped around a refrigerant pipe. The resin foam and the refrigerant pipe are preferably in contact with each other, but other members may be interposed between them. By joining the nonwoven fabric to at least one surface of the polyethylene resin foam by fusion or adhesive bonding, the heat-insulating material for preventing or suppressing dripping of condensation water of the present invention can be obtained.

[0037] [Nonwoven fabric and its base fiber (thermoplastic resin fiber)] In the present invention, the fiber of the nonwoven fabric is a mixture of thermoplastic resin fiber as the base fiber and a predetermined amount of superabsorbent resin fiber, but a nonwoven fabric consisting of only thermoplastic resin fiber and a nonwoven fabric consisting of a mixture of thermoplastic resin fiber and superabsorbent resin fiber at a predetermined blend ratio may also be used in combination. First, the thermoplastic resin fiber that constitutes the base fiber will be described.

[0038] When thermoplastic resin fibers are used in nonwoven fabrics consisting only of base fibers, they are intended to have a diffusive / transpiration function. Therefore, they do not need to have a water-absorbing function. On the other hand, when used in nonwoven fabrics consisting of base fibers mixed with superabsorbent resin fibers at a predetermined blend ratio, they are also used to form the skeleton of these nonwoven fabrics and hold the superabsorbent resin fibers. This is expected to not only impart shape stability and a predetermined strength to the nonwoven fabric, but also to diffuse and evaporate moisture adsorbed to the surface of the nonwoven fabric due to surface tension. Therefore, the base fiber itself does not need to have water absorption properties. Note that the nonwoven fabric in this invention is one in which at least a portion of the thermoplastic resin fibers are fused or bonded to each other.

[0039] When these thermoplastic resin fibers are mixed with superabsorbent resin fibers, they form the skeletal structure of the nonwoven fabric. The role of a nonwoven fabric composed solely of thermoplastic resin fibers is to improve water absorption and diffusion through capillary action by the thermoplastic resin fibers forming the skeletal structure, as estimated from the results of the retention parameter test described below. However, to promote water evaporation, it is preferable for the water retention of the nonwoven fabric to be not too high. It is preferable for the nonwoven fabric to retain water through surface tension, rather than through chemical bonding or by capturing it in a gel, as with superabsorbent resin fibers. Furthermore, if a thermoplastic resin fiber layer is placed on the opposite side of the outer surface of the superabsorbent resin fiber layer, the surface of the thermoplastic resin fiber layer will be covered by the superabsorbent resin fiber layer, so it is preferable to use the thermoplastic resin fiber layer as the outer surface. From this perspective, chemical-based synthetic fibers can be used as the fibers constituting the nonwoven fabric. Thermoplastic resin fibers are used as chemical-based synthetic fibers, and polyester fibers, polyethylene fibers, polypropylene fibers, acrylic fibers, etc. can be used. More specifically, examples include monofilaments of polypropylene (PP), polyethylene (PE), or polyethylene terephthalate (PET), or fibers with a core-sheath structure of these (specifically, fibers with a core-sheath structure of polyethylene terephthalate / polyethylene, polyethylene terephthalate / polypropylene, or polypropylene / polyethylene), or fibers in which any of these fibers is mixed with other fibers. Examples include nonwoven fabrics in which at least some of these thermoplastic resin fibers are fused or bonded to each other. Examples of such other fibers include acrylic resins.

[0040] Acrylic fibers are fibers made of a linear synthetic polymer containing 85% or more by mass of repeating units of acrylonitrile groups. Although the strength of acrylic fibers decreases slightly when they absorb moisture, their wet / dry strength ratio is 0.9 or more, and the decrease in strength is slight compared to natural fibers such as rayon and vinylon. Therefore, there are no major problems when acrylic fibers are used as a blend with other non-absorbent fibers.

[0041] As the thermoplastic resin fiber, a mixture of two types of fibers can be used, or a nonwoven fabric using fibers with a core-sheath structure can be used. The advantages of using such fibers with a core-sheath structure in a nonwoven fabric are as follows: When fusing fibers together, for example, by using polyethylene terephthalate fibers or polypropylene fibers for the core and polyethylene fibers for the sheath, it is possible to fusing the fibers together at a relatively low temperature of 120 to 140°C. This not only makes it easier to manufacture the nonwoven fabric, but also increases the rigidity of the fibers used in the nonwoven fabric by using fibers with higher strength for the core than for the sheath, which allows the fiber diameter of the fibers constituting the nonwoven fabric to be reduced accordingly.

[0042] As the thermoplastic resin fibers, multiple fibers with different melting points can be used, and the fibers with a lower melting point can be melted and used as a binder to form a nonwoven fabric. Here, if PET fibers and polyethylene fibers are mixed and used in a predetermined ratio, the polyethylene fibers act as a binder. For example, PET resin can be used as the main constituent fiber, and copolymer polyester (Co-PET) resin, polypropylene resin, polyethylene resin, etc. can be used as the low-melting-point fiber used as the binder. By using the above structure, it becomes easier to control the strength of the nonwoven fabric.

[0043] Here, nonwoven fabrics can be made using a combination of thermoplastic resin fibers with a core-sheath structure and other fibers with different melting points. For example, by using a fiber with a higher strength for the core than for the sheath, the rigidity of the fibers used in the nonwoven fabric can be increased. At the same time, by using high-strength fibers or hollow fibers as other fibers and controlling the mixing ratio of the two, it is possible to improve the mechanical properties of the nonwoven fabric and impart flexibility to the nonwoven fabric.

[0044] Furthermore, when long fibers are used as thermoplastic resin fibers, the fibers tend to be oriented in the MD direction, which is the main direction during the production of nonwoven fabrics. As a result, the mechanical properties in the MD direction tend to be higher in rigidity than the mechanical properties in the TD direction. Therefore, when used as a base fiber to form a skeleton by mixing with superabsorbent resin fibers, the skeleton structure is stabilized. Therefore, it is desirable to use long fibers. A predetermined amount of short fibers can also be added to the long fibers to form a mixed fiber. In this way, using a portion of short fibers can mitigate the influence of fiber orientation in the MD direction and improve orientation in the TD direction, which is expected to improve anisotropy.

[0045] [Method for manufacturing nonwoven fabric using thermoplastic resin fibers] Next, we will review the method for manufacturing nonwoven fabric using thermoplastic resin fibers. Normally, nonwoven fabrics are formed by forming a thin, membrane-like sheet called a web made only of fibers, and then bonding the fibers that make up the formed web to each other only in the necessary portions as needed.

[0046] There are various methods for forming nonwoven fabrics made of thermoplastic resin fibers, and for example, there are both wet and dry methods for forming webs. In the wet method, fibers are made into a nonwoven fabric in a manner similar to that used in papermaking, and there are various methods for forming webs in the dry method, as described below. Either method may be used to form a web, but for the purpose of preventing or suppressing dripping of condensation water according to the present invention, when long fibers are used, the fibers must be bent to form the three-dimensional structure of the nonwoven fabric, and therefore it is desirable for the fibers of the nonwoven fabric to have crimping properties that allow them to bend.

[0047] Furthermore, to obtain a nonwoven fabric from a web of thermoplastic resin fibers, the fibers forming the web must be bonded at predetermined positions. Here, various methods for bonding the fibers in a web include chemical bonding methods such as dipping and spraying, thermal bonding, spunbonding, meltblowing, meltplaining, airlaying, spunlace (water exchange method), and needlepunching. Here, methods for forming nonwoven fabrics using long fibers include the following chemical bonding, thermal bonding, spunbonding, meltblowing, and meltplaining. Methods for forming nonwoven fabrics using short fibers include the chemical bonding, thermal bonding, airlaying, and needlepunching. Note that the chemical bonding, thermal bonding, and airlaying methods can be used for both long and short fibers.

[0048] Specifically, the chemical bonding method is a method of partially bonding a web with an adhesive, and the thermal bonding method is a method of mixing low-melting point heat-fusible fibers and passing them between heated rolls to heat-bond them, or of applying hot air to bond the heated parts of the fibers with the melted fibers, thereby bonding the fibers together. The spunbond method is a method of arranging fibers directly in connection with spinning and forming them into a cloth using self-fusing heat. The meltblowing method is a method of arranging fibers directly in connection with spinning and entangling ultrafine fibers. The meltblown method is a method of melting a resin and thinning the fibers using high-temperature air sprayed from the periphery of a spinning nozzle to accumulate them into a sheet.

[0049] The air-laying method is a method of bonding pulp with air and a binder to form a nonwoven fabric. The spunlace method is a method of entangling fibers using a high-pressure water jet. The needle-punch method is a method of producing a nonwoven fabric by repeatedly piercing a web with special needles that move up and down at high speed, entangling the fibers with the protrusions formed on the needles. When laminating nonwoven fabrics, the lamination method is not particularly limited. However, when laminating the first and second layers, since the second layer contains a predetermined proportion of superabsorbent resin fibers, wet methods such as spunlace are not preferred. Lamination by thermal bonding, chemical bonding, or needle-punch is preferred. However, the present invention does not limit the manufacturing method of the nonwoven fabric or its laminate. Mixing different fibers is typically performed using a carding machine, but any known method other than a wet method can be used.

[0050] [Superabsorbent resin fiber] Superabsorbent resins have high water absorption properties, and have the effect of retaining absorbed moisture in a gel structure formed by crosslinking the polymer, and at the same time, have an equilibrium moisture absorption rate, so they have the property of absorbing moisture under high humidity conditions and releasing moisture under low humidity conditions. Examples of superabsorbent resin fibers include crosslinked acrylate fibers, fibers obtained by hydrolyzing the surface of acrylic fibers through post-processing, and fibers obtained by graft-polymerizing acrylic acid or methacrylic acid onto fibers such as polyester. Among these, crosslinked acrylate fibers are particularly preferred because of their high water absorption properties.

[0051] The water-absorbing properties of superabsorbent polymers are explained using the example of polyvinyl alcohol and polyacrylic acid. In the case of polyvinyl alcohol / polyacrylic acid-based superabsorbent polymers, islands of sodium polyacrylate exist within a sea of ​​polyvinyl alcohol, with the crystallized polyvinyl alcohol acting as crosslinking points for the sodium polyacrylate. This water-absorbing polymer consists of two layers: a polyvinyl alcohol-rich portion and a polyacrylic acid portion, with the former encompassing the latter, forming a microphase-separated structure. While the polyvinyl alcohol phase exhibits some water-swelling properties, its water absorption is primarily due to the polyacrylate phase. When the vinyl alcohol phase expands to several hundred times its polyacrylate phase, it is stretched and undergoes so-called oriented crystallization. The strength of the crystallized polyvinyl alcohol is extremely high, making it one of the toughest polymers. Therefore, polyvinyl alcohol / polyacrylic acid-based superabsorbent polymers exhibit a composite structure in which the crystallized polyvinyl alcohol portion supports the highly water-absorbent polyacrylic acid portion, resulting in a gel that remains rigid even in the water-absorbed state.

[0052] Here, we will discuss "absorbent fibers" that are contrasted with superabsorbent resin fibers. Absorbent fibers such as cellulose fibers, pulp, and rayon fibers have water absorption properties, but compared to nonwoven fabrics using superabsorbent resin fibers, they do not absorb water in excess of their own weight. Therefore, compared to nonwoven fabrics using superabsorbent resin fibers, they are inferior in both water absorption and water retention. Conversely, superabsorbent resin fibers can be defined as fibers or aggregates thereof that exhibit water absorption in excess of their own weight, and preferably absorb at least two times their own weight, more preferably at least five times their own weight, and even more preferably at least 10 times their own weight.

[0053] Superabsorbent resin fibers are composed of resins that have excellent water absorption properties and swell upon water absorption. Fibers containing polymers with hydrophilic groups are preferably used, and a representative example of such fibers is crosslinked acrylic acid-based fibers. Such crosslinked acrylate-based fibers are obtained by crosslinking a polymer obtained by reacting an acrylic acid-based monomer with a monomer having a functional group capable of forming a crosslink with the acrylic acid-based monomer. These monomers may be used alone or in combination. However, it is preferable that the acrylic acid-based monomer and the functional group monomer have a functional group equivalent to or less than the acrylic acid. Furthermore, when reacting these, other vinyl monomers, such as vinyl acetate (VA) and acrylonitrile, can be blended to impart plasticity.

[0054] Representative examples of suitable commercially available crosslinked acrylic acid fibers include "Belloasis" (registered trademark) manufactured by Teijin Fibers Ltd. and "Lanseal" (registered trademark) manufactured by Toyobo Co., Ltd. For example, "Belloasis" (registered trademark) exhibits excellent water absorption performance, being able to absorb up to 80 times its own weight in water. Here, in the case of short-fiber nonwoven fabrics, the superabsorbent resin fibers are mainly formed into a web by the airlaid method or the carding method, and the fibers forming the web are bonded together by the thermal bonding method or the chemical bonding method, but in some cases they can also be produced using the needle punch method.

[0055] [Method of bonding nonwoven fabric to polyethylene-based resin foam] The method of bonding the nonwoven fabric and the resin foam is not particularly limited, but for example, the nonwoven fabric and the polyethylene-based resin foam can be fused or bonded by placing the nonwoven fabric on one surface of the resin foam and performing hot roll molding. Alternatively, the nonwoven fabric can be fixed to the surface of the polyethylene-based resin foam by applying an adhesive to one surface of the polyethylene-based resin foam and then performing hot roll molding with the nonwoven fabric placed on the surface of the polyethylene-based resin foam.

[0056] [Piping Structure] The heat-insulating cover member 5 for preventing or suppressing dripping of condensed water according to the preferred embodiment of the present invention described above forms a piping structure including at least one of horizontal, oblique, vertical, and curved piping covered on the outer periphery of a refrigerant pipe 1 (see FIGS. 1A and 1B). In this case, the refrigerant pipe is covered with each heat-insulating cover member so that the surface of a single-layer nonwoven fabric or the surface of either the first or second layer of a laminated nonwoven fabric becomes the outer surface (see FIG. 3). Alternatively, the heat-insulating cover member 5 for preventing or suppressing dripping of condensed water covers the outer periphery of each of two refrigerant pipes 1, 1, and the heat-insulating cover members 5 are heat-sealed or bonded to each other to form a glasses-shaped cross-section pipe 20 (see FIGS. 2A and 2B). In this case, in a piping structure including horizontal, diagonal, vertical, or bent piping, the outer periphery of each refrigerant pipe in the piping structure is covered with a single-layer nonwoven fabric heat-insulating cover member for preventing or suppressing dripping of condensation water, or the surface of either the first or second layer of a laminated nonwoven fabric, as the outer surface. The refrigerant pipes are arranged facing each other, and the outer surfaces of the nonwoven fabrics are heat-sealed or bonded to form an eyeglass-like integrated structure. Another example of a piping structure 30 is one in which the nonwoven fabric has a laminated structure and is disposed on a resin foam 2 with either the second layer (layer containing superabsorbent polymer fibers) 32 or the first layer (layer not containing superabsorbent polymer fibers) 31 as the outer surface, forming the heat-insulating cover member 5, and the refrigerant pipe 1 is covered (see FIGS. 3, 5A, and 5B). In the condensation water dripping confirmation test using vertical vertical piping, which will be described later, vertical piping is most susceptible to the effects of gravity compared to horizontal piping, diagonal piping, bent piping, etc. Furthermore, in terms of piping structure, condensation water is more likely to be retained in the recesses near the joints of eyeglasses-type piping than in single pipes, and this retained condensation water is more likely to form droplets and drip, making the test conditions more severe. For this reason, the condensation water dripping confirmation test was conducted by installing eyeglasses-type piping in a vertical piping.

[0057] 6 is a cross-sectional view schematically illustrating a piping structure 40 (assembly piping) according to yet another preferred embodiment of the present invention. In this embodiment, a refrigerant pipe 1 having two resin foams 2 disposed therein, a drain pipe 12, and wiring pipes 13 are housed inside a heat-insulating cover material 5 for preventing or suppressing dripping of condensed water. In this case, the piping structure preferably includes at least horizontal, oblique, vertical, or curved pipes, with one or more refrigerant pipes, drain pipes, and wiring pipes housed inside the heat-insulating cover material for preventing or suppressing dripping of condensed water. Furthermore, in this embodiment, the outer surface of the heat-insulating cover material for preventing or suppressing dripping of condensed water is the surface of a single-layer nonwoven fabric or the surface of either the first or second layer of a laminated nonwoven fabric, and the outer peripheral surface of the heat-insulating cover material for preventing or suppressing dripping of condensed water has a substantially cylindrical cross-section. One example of a form in which condensation water from the refrigerant piping, drain pipes, and wiring inside the piping structure 40 is enclosed in a heat-insulating cover member for preventing or suppressing dripping, so that the condensation water can be housed inside the heat-insulating cover member for preventing or suppressing dripping. This makes it possible to suitably suppress or prevent dripping of condensation water even if condensation water forms on the outer surface of the heat-insulating cover member for preventing or suppressing dripping, which is the outermost layer of the piping structure 40.

[0058] Although the above has been described in relation to a heat exchanger piping structure, the cover member of the present invention is not limited to heat exchanger piping. It can also be used as a structure in which the cover member is attached to the outer periphery of a duct for a heat exchanger by attaching the polyethylene resin foam surface to the outside of the duct so as to cover the outer periphery of the duct. In this way, even when used as a duct structure in which the cover member of the present invention is attached to the outer periphery of the duct, it is expected to have the same effect of preventing or suppressing the dripping of condensation water on the duct surface as in the case of heat exchanger piping.

[0059] <Method for Measuring Product Characteristics and Basic Physical Properties of Nonwoven Fabrics> (Nonwoven Fabric Thickness) The nonwoven fabrics used in the tests had thicknesses ranging from 0.66 mm to 1.22 mm. The thickness of the nonwoven fabric used in the tests was measured according to the JIS method using a nonwoven fabric thickness measuring device (φ56.4 mm disc flat probe) capable of performing the same measurement as Method A of the measurement method described in the JIS General Nonwoven Fabric Measurement Method (JIS L1913:2010). The thickness of the nonwoven fabric was measured three times, and the average value was taken as the measured value. The thickness of the first layer of the laminate was measured because, when the laminated nonwoven fabric was peeled off, the nonwoven fabric deformed upon peeling, making it impossible to maintain the thickness of the nonwoven fabric at the time of lamination. For this reason, the test material was cut with a fine cutter, and the thickness direction of the nonwoven fabric of the cross section was observed under SEM, and the thickness was measured by comparing with the scale on the SEM. Three test pieces were prepared for the measurement, and the measurement results of the three pieces were taken as the thickness of the first layer of the nonwoven fabric. The thickness of the second layer was calculated by subtracting the thickness of the first layer from the total thickness of the nonwoven fabric.

[0060] (Fiber diameter, basis weight) The fiber diameter of the nonwoven fabric was determined by randomly selecting 20 points from an SEM fiber image and calculating the average fiber diameter (number average) using image processing software. Here, the average fiber diameter of the nonwoven fabric used in the present invention is 16.67 μm to 35.25 μm. The basis weight can be calculated by cutting 10 cm x 10 cm square test pieces from the raw material, measuring the mass and area of ​​each, and using the following formula. The measurement was repeated three times and the average value was taken as the basis weight. The basis weight (g / m ２ ) = 10000 × test piece mass (g) / test piece area (cm ２ )

[0061] (Moisture Retention Capacity Parameter: Figure 7) When moisture condenses on the surface of a nonwoven fabric, diffusion due to surface tension and absorption compete with each other. Therefore, in order to prevent condensation from dripping, particularly under gravity, the ability to absorb and diffuse moisture upward against gravity is important, and the balance between these functions is crucial. In the present invention, to evaluate this, a unique test method was developed and used to determine the moisture retention capacity parameter, including the ability to absorb moisture under gravity. Here, the moisture retention capacity parameter test involves horizontally placing a rectangular test piece made of a nonwoven fabric containing various blend ratios of superabsorbent polymer fibers and having a predetermined size and a gauge line across the width of the surface at the midpoint in the longitudinal direction, dropping a predetermined amount of colored test liquid on the gauge line, and then immediately holding the test piece vertically for 5 minutes after the drop. The ascending distance from the marking line of the test specimen to the point where the test liquid reached and the descending distance from the marking line of the test specimen to the point where the test liquid reached were then measured. The average ascending distance was divided by the average descending distance, and the ratio was used to determine the moisture retention parameter. This value represents the ratio of the ascending and descending lengths; the larger the value, the better the "moisture retention ability against gravity." Higher moisture retention ability is believed to be able to suppress condensation water dripping at low positions. The moisture retention parameter was determined by cutting the nonwoven fabrics produced in the Examples and Comparative Examples (including, if necessary, the superabsorbent polymer fibers and the like of the respective blend ratios used in the Examples and Comparative Examples) into strip-shaped test specimens 41 (Figure 7) measuring 200 mm long x 25 mm wide, and marking the surface with a marking line 45 across the width at the midpoint in the longitudinal direction. The thickness of the nonwoven fabric was determined as the thickness of each test material used in the Examples and Comparative Examples. With the test piece held horizontally, 400 μL of colored test liquid was dropped onto the marked line, and immediately after the dropping, the test piece 41 was held vertically for 5 minutes, and then the ascending distance 43 from the marked line on the test piece to the point where the test liquid reached, and the descending distance 44 from the marked line on the test piece to the point where the test liquid reached were measured.Furthermore, the average value of the upward ascent distance 43 from the marked line of the test piece (the ascent distance to the point where the test liquid reaches upward) in the width direction of the test piece (the average value of the ascent distances of #1 to #5) was divided by the average value of the downward descent distance 44 from the marked line of the test piece (the descent distance to the point where the test liquid reaches downward) in the width direction of the test piece (the average value of the descent distances of #1 to #5), and this average ascent distance was divided by the average descent distance to obtain the moisture retention parameter. Since there is a distribution in the width direction as shown in Figure 7, the measurement position was equally divided in the width direction to obtain the average value of five locations, and the average length of the ascent [mm] was divided by the average length of the descent [mm] to calculate the value, which was defined as the moisture retention parameter against gravity. The measured values ​​in the table are the average values ​​obtained by repeating this measurement five times. This value represents the ratio of the length of the ascent portion 43 to the descent portion 44, and the larger the value, the better the "moisture retention against gravity" performance. It is believed that a high water retention parameter can prevent condensation water from dripping at low positions. Therefore, a high water retention parameter is desirable for performance such as preventing or suppressing condensation water dripping. However, in reality, it is believed that the water retention parameter and the water retention capacity of the nonwoven fabric have complementary effects on preventing or suppressing condensation water dripping.

[0062] (Evaluation of Water Retention Capacity in an Evaporative Environment: Figures 8A and 8B) In the present invention, taking into account the water retention function of nonwoven fabrics containing superabsorbent resin fibers, it is necessary to determine the water retention capacity in an evaporative environment in addition to the water retention parameter test described above. However, since there are no test standards for determining water retention capacity, the following water retention test in an evaporative environment was devised and conducted. The water retention evaluation method is as follows (see Figures 8A and 8B). First, a thermal insulation cover member 5 consisting of a resin foam 2 and a nonwoven fabric 3 was wrapped around the outer circumference of a 25 mm diameter pipe 11 cut to 150 mm to form the thermal insulation cover member 5, and both ends of the thermal insulation cover member 5 were fused to create a water retention test material 100. The thickness of the resin foam 2 in this case was 10 mm. The nonwoven fabric was the same thickness as the test materials prepared in the Examples, Comparative Examples, and Conventional Example Material 1, and, if necessary, contained the same proportion of superabsorbent resin fibers and the like as the respective test materials. Next, the test material 100 was placed in a transparent resin container 51 with a predetermined clearance to allow insertion of a 150 mm long test material, as shown in the figure, and the "container + test material mass" was measured using an electronic balance (scale) 53. 20 g of water 52 was placed in the container 51 containing the test material 100, and the total mass of the "container + test material + 20 g of water" was measured using an electronic balance. The temperature and humidity chamber was set to a temperature of 23 ° C and a humidity of 30%, and the container containing the water 52 and test material 100 was inserted into the temperature and humidity chamber and held in the temperature and humidity chamber for 6 hours. After 6 hours, the container 51 immersed in the test material 100 was removed, and the "mass at removal," "remaining water amount," and "mass after water removal" were measured using an electronic balance 53. Here, the water retention capacity can be determined by tilting the container to remove water from the mass at the time of removal at the end of the test to determine the mass after water removal, and then subtracting the mass of the container and the sample before the test from this. The amount of evaporation is the total mass before the start of the test minus the mass at the time of removal.

[0063] (Specifications of test materials, moisture retention parameters and test results of water retention test) The test results of the test materials are shown in Table 1.

[0064]

[0065] (Table notes) SAF: Super Absorbent Fiber BELLOASIS (trade name) manufactured by Teijin Frontier Co., Ltd. LANSEAL (trade name) manufactured by Toyobo Co., Ltd. PE: Polyethylene PET: Polyethylene terephthalate Foam: Polyethylene resin foam Expansion ratio 30 times, thickness 10 mm The numerical values ​​and % shown for the SAF content (%) all mean mass %. Products that satisfied both the water retention parameter and water retentivity were marked with a "◯" as a pass (Good), and products that did not satisfy this were marked with a "X" as a fail (Bad).

[0066] (Explanation of Test Materials) The test materials will be explained below, but in the explanation of the test materials and in the description of the evaluation test results of these test materials, the names of the resins constituting the fibers will be abbreviated as PE, PP, PET, SAF, etc. for simplicity. The blend ratio in the present invention is the blend ratio of the superabsorbent polymer fiber to the total weight of the layer containing the superabsorbent polymer fiber.

[0067] First, the production of the resin foam will be described. A mixed resin was prepared by mixing low-density polyethylene and high-density polyethylene in a mass ratio of 4:6 as the polyethylene-based resin. The low-density polyethylene used was F120N manufactured by Ube Maruzen Polyethylene Co., Ltd., and the high-density polyethylene used was HD1300 manufactured by Japan Polyethylene Corporation. Furthermore, 16 parts by mass of Vinihall AC#LQ manufactured by Eiwa Kasei Co., Ltd. (trade name) was added as a foaming agent, and 0.8 parts by mass of Percumyl D manufactured by Nippon Oil & Fats Co., Ltd. (trade name) was added as a cross-linking agent. The resulting raw material composition was extruded at 120-150°C to obtain a foaming base sheet, which was then continuously foamed to a thickness of 10 mm and 30 times the original size in a heating furnace at 200-230°C. The resin foam was then passed through rolls to adjust its dimensions and surface properties, and then cut to a predetermined width corresponding to the diameter of the pipe to be wrapped around. The resin foam is typically 10 mm thick, but can be made larger than 10 mm if necessary. The reason for this is that when the foaming ratio is approximately the same, increasing the thickness of the foam improves the heat insulating properties and makes it easier to suppress condensation.

[0068] The inventive materials include a single-layer product consisting of a single-layer nonwoven fabric made of a predetermined blend of thermoplastic resin fiber and superabsorbent polymer fiber, and a laminated product in which only a skeletal resin fiber layer containing no superabsorbent polymer fiber is laminated to the single-layer product. The single-layer product was prepared by heat-bonding a predetermined ratio of superabsorbent polymer fiber (Belloasis) to the surface of a polyethylene resin foam, with the skeletal resin fiber being a core-sheath structure fiber of PET / PE (PET core / PE sheath). The test materials 1, 2, 3, and 4 in the examples had blend ratios of 10%, 25%, 40%, and 75% by mass of superabsorbent polymer fiber relative to the nonwoven fabric layer containing the superabsorbent polymer fiber for the single layer. Inventive material 5, the single-layer product used a core-sheath structure fiber of PET and PP / PE, with 50% by mass of Lanseal (other than Belloasis) as the superabsorbent polymer fiber. In the table, the 30%, 20%, and 50% listed under the SAF content (%) for test material 5 represent the content, as described above, and indicate 30 mass%, 20 mass%, and 50 mass%, respectively.

[0069] In contrast, the laminated product is a product in which a nonwoven fabric consisting only of a skeletal resin fiber layer is laminated onto the single-layer nonwoven fabric. Here, the layer consisting only of skeletal resin fiber is referred to as the first layer, and the nonwoven fabric layer containing superabsorbent polymer of the laminated nonwoven fabric is referred to as the second layer. The second layer, which is a nonwoven fabric containing superabsorbent polymer fiber in the nonwoven fabric of the laminated product, has the same composition ratio as the single-layer product, at 10 mass%, 25 mass%, 40 mass%, and 75 mass%, respectively, and the first layer consisting only of a skeletal structure nonwoven fabric with a core-sheath structure of PET / PE is attached to these, resulting in invention examples 6, 7, 8, and 9. In invention example 10, the second layer, which is a nonwoven fabric containing superabsorbent polymer fiber in the nonwoven fabric of the laminated product, has the same composition ratio as invention example 8, at 40 mass%, but the basis weight of the nonwoven fabric is 48 g / m ３ 63g / m ３ Inventive example material 11, a mixed fiber of PET and PET / PP core-sheath structure fiber is used as the skeletal resin fiber, Belloasis is replaced with Lanseal at a mixing ratio of 50 mass%, and the basis weight of the nonwoven fabric is 168 g / m ２The arrangement of the nonwoven fabric of each laminate was evaluated in two ways: Arrangement A, in which the first layer (not containing superabsorbent polymer fibers) was the outer layer and the second layer (containing superabsorbent polymer fibers) was the inner layer, and Arrangement B, in which the first layer (not containing superabsorbent polymer fibers) was the inner layer and the second layer (containing superabsorbent polymer fibers) was the outer layer.

[0070] The conventional material, designated as Conventional Material 1, was a thermal insulation cover member in which a 100 μm-thick PE film (manufactured in-house) was fused to the surface of a polyethylene resin foam. Comparative materials were also tested. These materials, designated as Comparative Material 1, 2, and 3, had the same structure as the inventive material, but contained a 5% by weight superabsorbent resin (Belloasis) in the nonwoven fabric. These materials were also tested in laminated versions with Belloasis content of 5% and 85% by weight, respectively. These comparative materials were designed to confirm whether a low 5% Belloasis content would prevent or suppress condensation in both the single-layer and laminated versions. The 85% Belloasis content, due to its high content of superabsorbent nonwoven fabric, provided sufficient condensation prevention or suppression, but was also designed to confirm whether there were any problems with adhesion or foamability with the polyethylene foam. Furthermore, since the single-layer and laminated versions of the comparative material with the higher Belloasis content were expected to exhibit similar behavior, only the laminated versions were tested. Furthermore, three types of commonly used nonwoven fabrics made only of skeletal resin fibers without containing superabsorbent resin were added to the comparative materials, and these were designated Comparative Materials 4 to 6. Here, the nonwoven fabrics of Comparative Materials 5 and 6 were prepared by adding absorbent fibers or materials such as rayon or pulp, as well as ordinary thermoplastic resin fibers, in addition to the skeletal resin fibers, in order to compare ordinary absorbent fibers or materials with superabsorbent resin fibers. Specifically, Comparative Material 4 was a nonwoven fabric with a PET / PE sheath-core structure in which the surface of the PE in the sheath was hydrophilically treated. Comparative Material 5 was a nonwoven fabric made of a blend of PE and rayon fibers, with a rayon content of 40% by mass. Comparative Material 6 was a nonwoven fabric made of a blend of PET / PE sheath-core structure fibers and pulp, with a pulp content of 30% by mass.

[0071] (Measurement and Evaluation Items of Nonwoven Fabrics and Their Details) The measurement and evaluation items of the nonwoven fabrics used in the test were fiber diameter, product thickness, basis weight, moisture retention parameter, and water retention. Here, the fiber diameter of the test material was recorded as both the fiber diameter of the base material skeleton resin fiber and the fiber diameter of the superabsorbent resin fiber (SAF). For product thickness, if the nonwoven fabric was a single-layer nonwoven fabric, the total thickness of the nonwoven fabric was recorded. If the nonwoven fabric was a laminated product, the total thickness of the laminated nonwoven fabric and the thickness of the first layer, which is the diffusion layer, were recorded in parentheses below the total thickness. Therefore, since the thickness of the second layer can be calculated by subtracting the thickness of the first layer from the total thickness as described above, the thickness of the second layer was not recorded in the table. Furthermore, for the basis weight, in the case of a single-layer product, the basis weight represents the basis weight of the entire nonwoven fabric. In the case of a laminated product, the basis weight of the entire nonwoven fabric was recorded in the upper row, and the basis weights of the first and second layers were recorded in order from left to right in the lower row. This is because there are two possible configurations: (A) the first layer is located on the outside and the second layer is located on the inside, and (B) the second layer is located on the outside and the first layer is located on the inside fused or adhesive surface. Here, it is believed that the first layer, consisting only of skeleton resin fibers and not of superabsorbent polymer fibers, located on the outside of the nonwoven fabric would have a more advantageous effect as a diffusion / evaporation layer. However, some of the water may pass through the superabsorbent polymer layer. Furthermore, considering only water retention, it is also believed that the reverse configuration, in which the diffusion layer is located on the inside fused or adhesive layer, would be more advantageous than the configuration in which the superabsorbent polymer fibers are located on the outside. Therefore, both configurations were evaluated. Hereinafter, regarding the configuration of the laminate, when a nonwoven fabric is bonded to the surface of a PE resin foam, the configuration in which the first layer, a nonwoven fabric formed only of a base skeleton resin, is located on the outer layer, will be referred to as Configuration (A) ( FIG. 5A ), and the configuration in which the second layer containing superabsorbent polymer fibers is located on the outer layer will be referred to as Configuration (B) ( FIG. 5B ). The water retention parameters and water retention amounts in Table 1 show test results for the case where the outer layer is the first layer (A) in the upper row and the case where the outer layer is the second layer (B) in the lower row. The blend ratio is the blend ratio of the superabsorbent polymer fiber to the total weight of the superabsorbent polymer-containing layer, as described above.

[0072] (Range of fiber diameter, product thickness, and basis weight) In the examples, the fiber diameter of the thermoplastic resin fiber was tested at 16.67 μm to 25.41 μm. In the examples, the fiber diameter of the SAF was tested at 23.74 μm to 35.25 μm. Specifically, the fiber diameter of the SAF, which is a superabsorbent resin fiber, was 35.25 μm for BELLOASIS and 23.74 μm for LANSeal. LANSeal has a core-sheath structure in which the SAF is formed on the outer periphery of an acrylic fiber core. In the examples, the product thickness was tested at a range of 0.77 mm to 1.22 mm. Note that for the laminates, the thickness of the first layer (layer without SAF) is shown in parentheses as described above. The basis weight was 38 g / m in the examples. ２ ~168g / m ２ In the case of laminated products, as described above, the basis weight of the entire nonwoven fabric is shown in the upper row, the basis weight of the first layer (layer without SAF) is shown on the left side of the lower row, and the basis weight of the second layer (layer with SAF) is shown on the right side, in that order.

[0073] (Water Retention Parameter Test and Water Retention Test Results for Nonwoven Fabrics) - Test Results for Inventive Materials: Looking at the results for the inventive materials, the test results for the single-layer products of Inventive Materials 1 to 5 showed water retention parameters ranging from 0.78 to 1.06, and the water retention amounts in the water retention test ranged from 7.89g to 19.98g. In addition, because Inventive Materials 6 to 9 are laminated products, the results differ depending on whether the test liquid is dripped onto the first layer (a diffusion / transpiration-promoting layer consisting only of base resin fibers) or the second layer (a layer containing superabsorbent polymer fibers in the base resin fibers). In this test, the dripped surface corresponds to the outer surface of the product's thermal cover member. When the dripped surface is the second layer containing superabsorbent polymer fibers in the base resin fibers, the water retention parameter ranges from 0.74 to 0.98, showing results similar to those for single-layer products. This is thought to be because the structure of the second layer of nonwoven fabric, which serves as the drip surface, is similar to that of a single-layer product, containing superabsorbent resin fibers within the base resin fiber. Therefore, when the blending ratio of superabsorbent resin fibers is the same, the diffusion and evaporation of water absorbed by the nonwoven fabric and water retention behave in a similar manner. Conversely, when the first layer is not placed on the drip surface but is placed behind the nonwoven fabric layer containing superabsorbent resin fibers, the effect of the first layer of diffusion and evaporation promotion layer, which is made only of base resin fibers and does not contain superabsorbent resin fibers, on the moisture retention parameter is minimal. Conversely, when the drip surface is a diffusion and evaporation promotion layer made only of the base resin fiber of the first layer, the moisture retention parameter is 1.02 to 1.16, which is higher than the moisture retention parameter of the second layer, which is 0.74 to 0.98. From this, it can be seen that, in terms of the positional relationship between the nonwoven fabric and the resin foam, it is desirable to place the first layer (a diffusion and evaporation promotion layer made only of base resin fibers) facing outward from the perspective of diffusion and evaporation performance. Furthermore, when comparing the moisture retention parameters of a single-layer product and a product in which the dripping surface is the second layer, the moisture retention parameter of the single-layer product is 0.78 to 1.06, while the moisture retention parameter of the product in which the dripping surface is the second layer is 0.74 to 0.98, which is considered to be almost the same, although there are some differences. The reason for this is thought to be that in both cases the dripping surface is formed by a nonwoven fabric layer containing a superabsorbent polymer formed by base resin fibers that form the skeleton and superabsorbent resin fibers.Here, we examined the water retention of Example Materials 6 through 9. While these materials had superior water retention parameters compared to Example Materials 1 through 5 (7.89 g to 19.98 g), their water retention was slightly lower than those of Example Materials 1 through 5. Furthermore, when considering whether the first or second layer was positioned facing the outside of the product, the first layer facing the outside resulted in significantly better water retention parameters than the second layer facing the outside because the diffusion / transpiration promoting layer was positioned facing the outside. However, because the water-retentive layer was positioned on the backside, the water retention was slightly inferior, contrary to the results for the water retention parameter. (First layer positioned on the outside: 7.22 to 15.88 g; second layer positioned on the outside: 7.58 to 16.45 g). Furthermore, Example Material 10, like Example Material 8, contained 40% superabsorbent polymer fiber by weight, and the basis weight of the layer containing the superabsorbent polymer fiber was 30 g / m. ２ From 45 g / m ２ It can be seen that inventive material 10, due to the effect of increasing the basis weight of the superabsorbent polymer fiber layer, both the water retention parameter and water retention are improved compared to inventive material 8. Inventive material 11, a blend of PET and PET / PP core-sheath structured fibers is used as the resin fiber, the superabsorbent polymer fiber is changed to Belloasis, Lanseal is added at a blending ratio of 50 mass%, and the basis weight of the nonwoven fabric is further increased to 168 g / m ２In this case, due to the higher basis weight, the content of superabsorbent polymer fibers was higher than that of Example Material 9, resulting in a significantly higher water retention capacity compared to other laminates. From the above, for the single-layer products of Example Materials 1 to 5, and the laminate products of Example Materials 6 to 11, with the first layer as the outer surface (listed at the top of each column in the table) and the second layer as the outer surface (listed at the bottom of each column in the table), all of the 17 types of cover members satisfied the nonwoven fabric water retention parameter test result of 0.70 or more, and also satisfied the water retention test result of 7.0 g or more. Furthermore, the above test results show that the laminate product with the first layer as the outer surface has the highest water retention parameter, but conversely, the water retention capacity of the single-layer product in the water retention test of the present invention was slightly higher than that of the laminate product. Here, comparing the single-layer product and the laminate product, the laminate product has a lower basis weight of the entire nonwoven fabric than the single-layer product, at 100 g / m². 2 In the following tests, both the water retention parameters and the results of the water retention tests satisfied the above values.

[0074] Conventional Material: Conventional Material 1 is a PE film, not a nonwoven fabric, so moisture retention parameter tests and water retention tests were not conducted. Test Results for Comparative Material: Looking at the results of the comparative materials, Comparative Material 1 has a low superabsorbent polymer fiber content of 5% by mass, so no improvement in the moisture retention parameter due to water absorption can be expected. However, because it has basic diffusion and transpiration capabilities, the moisture retention parameter barely exceeded 0.70. However, the water retention test results were below 7.0 g due to the low superabsorbent polymer fiber content. Comparative Material 2 is a laminate, but like Comparative Material 1, the superabsorbent polymer fiber content was low at 5% by mass. As a result, like Comparative Material 1, the moisture retention parameter slightly exceeded the threshold, but the water retention was below the threshold of 7 g. In contrast, Comparative Material 3, due to its high superabsorbent resin fiber content of 85% by mass, had a water retention parameter exceeding 0.70 and a water retention test result exceeding 7.0 g. However, the skeletal base resin fiber content of 85% by mass was too high, resulting in unstable fusion or adhesion surfaces with the PE resin foam. Furthermore, the expansion and gelation of the superabsorbent resin fiber after water absorption caused the surface shape of the nonwoven fabric of the cover member to become unstable. As a result, Comparative Material 3 was deemed unsatisfactory. Comparative Material 4 was a nonwoven fabric composed solely of PET / PE core-sheath fibers. Although it did not contain superabsorbent resin fibers, the fiber surface was hydrophilically treated. Therefore, the water retention parameter exceeded the threshold, but the water retention capacity was below the threshold. Comparative Material 5 was a nonwoven fabric composed of a blend of PE and rayon fibers with a rayon fiber content of 40% by mass. Although the water retention parameter of Comparative Material 5 was below the target, its water retention was likely above the target due to the inclusion of rayon. As a result, neither the water retention parameter nor the water retentivity exceeded the target. Furthermore, Comparative Example 6, a nonwoven fabric made of a blend of PET / PE sheath-core fiber and pulp, exceeded the target water retention parameter, but did not achieve the target water retention, despite the blend of pulp. As described above, all of the comparative examples, except for Comparative Example 3, which had a high content of superabsorbent resin fiber, failed to meet the thresholds for either the water retention parameter or the water retention capacity in the water retention test, and therefore failed.Comparative example material 3 had a high content of superabsorbent resin fibers and a low content of base resin fibers that form the skeleton, which resulted in an unstable fused or adhesive surface at the interface with the PE resin foam, and the surface shape of the nonwoven fabric also became unstable, so it was rejected.

[0075] In addition to water retention, evaporation from the nonwoven fabric surface also contributes to preventing condensation. While not specifically shown in Table 1, the evaporation rates for the test materials ranged from 5.08 g to 11.48 g for single-layered inventive materials 1 through 5. For inventive materials 6 through 11, the evaporation rates were 9.24 g to 10.76 g when the outer layer was the first layer (a diffusion-transpiration-promoting layer consisting only of base resin fibers). Furthermore, the evaporation rates for inventive materials 6 through 11, which had a second outer layer (a layer containing superabsorbent resin fibers within the base resin fibers), were 8.88 g to 10.24 g. This demonstrates that not only does the nonwoven fabric retain water, but evaporation from the nonwoven fabric surface also contributes to preventing condensation. The inventive materials exhibited an evaporation rate of at least 5.0 g, while the evaporation rate for laminated materials alone was 8 g or more, and when the first layer was placed on the outer surface, an evaporation rate of 9 g or more was observed. Moreover, the laminate has a large transpiration effect, and this effect is combined with the water retention effect, which is thought to improve the effect of preventing or suppressing the dripping of condensed water.

[0076] (Purpose and Contents of Condensation Water Drip Confirmation Test) Based on the results of the moisture retention parameter test and water retention test of nonwoven fabrics, it was determined that a condensation water drip prevention or drip-suppression heat-insulating cover member in which a nonwoven fabric having a moisture retention parameter of 0.70 or more and a water retention capacity of 7.0 g or more in a water retention test determined under the specified conditions specified in the present invention is fused or bonded to the surface of a resin foam is considered to have excellent condensation prevention performance. Therefore, a condensation water drip performance confirmation test was conducted using these cover members and comparing them with conventional materials. Here, while it has already been confirmed that the product of the present invention does not drip condensation water on horizontal piping, it is necessary to confirm the condensation water drip performance on piping other than horizontal piping. For the condensation water drip confirmation test, we selected a vertical piping, which is most susceptible to the effects of gravity, from among horizontal, diagonal, vertical, and curved piping, to conduct the test. Furthermore, the use of eyeglass-shaped piping, structurally speaking, allows condensation water to be retained in the recesses formed near the joints of eyeglass-shaped piping compared to single pipes. This retained condensation water is more likely to form droplets and drip due to the influence of gravity, resulting in more severe test conditions. Therefore, this structure was chosen. Furthermore, to measure the actual amount of condensation water dripping, eyeglass-shaped piping was installed vertically in a large thermo-hygrostat chamber. Refrigerant was flowed through the piping, and exposure tests were conducted for 1,080 minutes (18 hours) under the actual operating conditions of the heat exchanger. The thermo-hygrostat chamber was set to harsh environmental conditions of 35°C and 90% RH. The reason for this is as follows: The environmental conditions that cause condensation water dripping vary from site to site. Therefore, even if condensation water dripping does not occur in the specified environment, it is possible that condensation water dripping will occur under more severe environmental conditions. Furthermore, if the test is conducted in a low-humidity environment, which is the actual installation environment, there is a possibility that dripping will not occur and it will be impossible to evaluate the drip prevention or drip suppression performance of condensation water between materials.However, in a harsh environment, dripping will occur, so it is possible to evaluate the drip prevention or drip suppression performance of condensation water between materials.Furthermore, this is because dripping of condensation water does not occur on horizontal piping.

[0077] (Condensation Water Dripping Confirmation Test Under Harsh Environmental Conditions Using Vertical Piping with Indoor Unit-Side Spectacle-Shaped Pipes: Figure 9) This is a piping configuration diagram that schematically illustrates a condensation water dripping confirmation test under harsh environmental conditions using vertical piping with indoor unit-side spectacle-shaped pipes. Specifically, a 600 mm drop pipe (indoor unit side piping) 71 (Figure 9) from the ceiling to the indoor unit side, an intermediate piping 73, and a descending piping (outdoor unit side piping) 72 were connected, and the device was prepared inside a large thermo-humidistat chamber. The device was subjected to a 1080-minute (18-hour) exposure test with the thermo-humidistat chamber set to high humidity conditions of 35°C x 90% RH, with the piping refrigerant temperature at 5°C, to conduct a harsh test to confirm condensation water dripping. For the test, a pair of pipes, one with a diameter of 6.35 mm and a wall thickness of 0.85 mm, and the other with a diameter of 9.52 mm and a wall thickness of 0.80 mm, were used. The condensation-preventing or drip-suppressing heat-insulating cover member 5 of the present invention was wrapped around the outer circumference of each pipe. The contact portions of the end faces of the resin foam 2 and the nonwoven fabric 3 of the cover member were then heat-sealed to each other, and the two pipes were then heat-sealed to form a pair of eyeglass-shaped pipes 20 (see Figures 2A and 2B). The outer diameters of the pipes wrapped with the heat-insulating cover member for preventing or suppressing dripping of condensation were approximately 28 mm and 31 mm, respectively. The mass of condensation water dripping was measured using an electronic balance 75 on a tray 400 mm long along the length of the pipes. Here, the setting conditions of the thermo-hygrostat chamber at 35°C x 90% RH are extremely harsh test conditions, where condensation occurs when the moisture content in the air in the thermo-hygrostat chamber is maintained and the temperature is lowered to 33°C, resulting in a so-called dew point of approximately 33°C. The test results for vertical piping showed an improvement of 30% or more for at least all of the inventive materials, with the amount of condensed water dripping being 33.6g or less, compared to the test result of Conventional Material 1 for vertical piping, which was 48g. Here, for the condensation water drip test results, those that satisfied the requirement of 33.6g or less were deemed to have passed, with "Good" being marked with "◯," and those that failed were marked with "Bad" being marked with "X."

[0078] (Nonwoven Fabric Bondability and Shape Stability Test) The state of the bonded interface between the nonwoven fabric (thermoplastic resin fiber) and the resin foam (polyethylene resin foam) of the molded heat-insulating cover member was visually confirmed. Those with no floating at the bonded interface were judged to pass, while those with problems with the bonded state at the interface, such as floating at the interface or even slight peeling, were judged to fail. Those with little change in shape of the nonwoven fabric due to water absorption in the superabsorbent resin fiber after the test were judged to pass (Good), while those with a significant change in shape of the nonwoven fabric that was significantly different from the shape before water absorption were judged to fail (Bad). In Table 2, "Good" is indicated by "◯" and "Bad" is indicated by "X."

[0079] (Test results of test materials for the condensation water drop test on a vertical pipe under harsh environmental conditions and the bond stability and shape stability of the nonwoven fabric) The test results of the test materials for the condensation water drop test on a vertical pipe under harsh environmental conditions and the bond stability and shape stability of the nonwoven fabric are shown in Table 2. Furthermore, as an overall evaluation, if the test results of both the condensation water drop test on a vertical pipe under harsh environmental conditions and the bond stability and shape stability test of the nonwoven fabric were both passed, the overall evaluation was recorded as "Good" (pass) with "◯", or if either of the tests was failed, the overall evaluation was recorded as "Bad" (failure) with "X". The test results of the individual inventive example materials and comparative example materials in Table 2 will be described in detail later. All of the inventive example materials, namely single-layer example materials 1 to 5 and laminate example materials 6 to 11, which are inventive example materials whose water retention parameter and water retention test results obtained under the specified conditions shown in Table 1 both meet the thresholds of a water retention parameter of 0.70 or more and a water retention capacity of 7.0 g or more in an evaporative environment, passed the condensation water drip test for vertical piping under harsh environmental conditions shown in Table 2 and the nonwoven fabric bonding stability and shape stability test, and were confirmed to be rated "Good" in both tests. From the above, it was confirmed that the thermal insulation cover members of inventive example materials 1 to 11 exhibit excellent condensation water drip prevention or suppression effects when checking condensation water dripping under harsh environmental conditions using vertical piping with eyeglass-type piping.

[0080]

[0081] In the results of the "Vertical Pipe Condensation Water Drop Test" in the table, the nonwoven fabric is a laminate, but the test results listed in one row (invention example materials 7, 9, 10, and 11) show the test results for Configuration A (where a layer not containing superabsorbent polymer fiber is the outer layer and a layer containing superabsorbent polymer fiber is the inner layer). The test results for invention example materials 6 and 8 are listed in two rows because the nonwoven fabric is a laminate, but the top row shows the test results for Configuration A, which has the same layer structure as above, and the bottom row shows the test results for Configuration B, where the outer and inner layers are reversed and tested (where a layer containing superabsorbent polymer fiber is the outer layer and a layer not containing superabsorbent polymer fiber is the inner layer). This is also true for comparison example materials 2 and 3.

[0082] As mentioned above, the "vertical piping condensation water drip test" was conducted by measuring the mass of condensation water dripping during a harsh test of 16 hours of exposure under environmental conditions of 35°C temperature and 90% humidity.The results showed that the amount of condensation water dripped by the inventive materials was improved by at least 30% compared to the conventional materials, but in contrast, the improvement in the amount of condensation water dripped by the comparative materials, except for comparative material 3 which contained 85% superabsorbent resin fiber, was less than 30%.Test results for conventional materials: Looking at the amount of condensation water dripped by the benchmark conventional materials, conventional material 1 dripped 48g of condensation water because it was simply a PE resin film fused to the surface of a PE resin foam. Test results for inventive materials: The results of the condensation water drip test for inventive materials 1 to 11 showed that when both the single-layer and laminated products had a nonwoven fabric layer containing a superabsorbent polymer, and the nonwoven fabric layer contained 10% to 80% superabsorbent polymer fiber by mass and 20% to 90% thermoplastic resin fiber, which forms the skeletal structure of the remainder of the nonwoven fabric, the condensation water drip amount for the single-layer products was 3.8g to 32.5g, an improvement of 32.3% to 92.1% compared to conventional material 1. For the laminated products, the condensation water drip amount was 0.8g to 28.4g, an improvement of 40.8% to 98.3% compared to conventional material 1, both the single-layer and laminated products exceeding 30% at least. In this case, when comparing the laminated products with the single-layer products, the laminated products were superior, with less condensation water dripping. This is thought to be because the laminated product has a separate layer that does not contain superabsorbent polymer fibers as a layer promoting diffusion and evaporation, which promotes the diffusion and evaporation of condensation water. Furthermore, for both the single-layer and laminated products, the amount of condensation water dripping tends to decrease as the superabsorbent polymer fiber content increases. This is thought to be due to the combination of the effects of increasing the water retention capacity of the superabsorbent polymer fibers as the superabsorbent polymer fiber content increases, and the resulting reduction in unretained condensation water, which in turn promotes the diffusion and evaporation of condensation water. Regarding the arrangement of the layer promoting diffusion and evaporation and the layer containing superabsorbent polymer fibers in the laminated product, the results of Test Samples 6 and 8 showed that placing the layer promoting diffusion and evaporation (first layer) on the outside resulted in less condensation water dripping than placing the layer promoting diffusion and evaporation on the inside.This is thought to be because placing the first layer on the outside slightly reduces water retention, but the improved water retention parameter allows for a greater evaporation effect, resulting in less condensation dripping than placing the first layer on the inside. Test results for comparative materials: Comparative material 1 is a single-layer base resin fiber mixed with 5% superabsorbent resin fiber by mass, resulting in a low amount of superabsorbent resin fiber and resulting in 42.5 g of condensation dripping (improvement rate: 11.5%). Comparative material 2 is a laminated base resin fiber mixed with 5% superabsorbent resin fiber by mass. As a result, 43.9 g of condensation dripping (improvement rate: 8.5%) occurred. As described above, conventional material 1, used as the standard before improvement, lacked both insulation and water retention due to structural reasons such as the absence of nonwoven fabric, resulting in poor test results. Furthermore, both Comparative Materials 1 and 2, both single-layer and laminated, contained a 5% superabsorbent polymer fiber content by mass. Compared to the inventive examples, the low content of superabsorbent polymer fiber in these test materials resulted in insufficient water retention, resulting in increased condensation dripping, below the 30% lower limit of the improvement rate for the inventive examples. Comparative Material 3 contained 85% superabsorbent polymer fiber in the laminated base resin fiber, exceeding the 80% upper limit of the inventive examples. As a result, the content of superabsorbent polymer fiber was higher than that of the inventive examples. Therefore, in a vertical pipe test, 2.6 g of condensation water was generated (94.6% improvement), similar to the inventive examples, and the condensation drip prevention or suppression effect was significant. However, while the high content of superabsorbent polymer fiber resulted in a high water retention capacity, the reduced content of base resin reduced the strength of the fusion or adhesive interface between the foam and nonwoven fabric, resulting in unstable bonding. Furthermore, the shape of the nonwoven fabric surface becomes unstable after absorbing water, and the superabsorbent resin fibers may fall off after absorbing water, so it was rejected as "Bad" and marked with an "X." Comparative Example Material 4 was a PET / PE core-sheath nonwoven fabric that did not contain superabsorbent resin fibers but had the surfaces of the core-sheath fibers treated with hydrophilicity, and this nonwoven fabric was bonded to the surface of a foam. In this case, the drip amount in the vertical piping test was 44.5 g (improvement rate: 7.3%), and although it is estimated that the hydrophilic treatment had a slight effect, the test result did not meet the 30% improvement rate of the inventive example material.Comparative Example 5 was a nonwoven fabric made of a blend of PE and rayon fibers, with 40% rayon fiber by mass relative to the total weight of the nonwoven fabric. The dripping amount for this material was 41.1 g (improvement rate: 14.4%), which did not reach the 30% improvement rate of the inventive example. Comparative Example 6 was a nonwoven fabric made of a blend of PET / PE core-sheath fiber and pulp, with 30% pulp by mass relative to the total weight of the nonwoven fabric. As a result, the dripping amount in the vertical piping test was 38.8 g (improvement rate: 19.2%). Comparative Example 6 was superior to the other conventional examples, but did not reach the 30% minimum improvement rate of the inventive example.

[0083] In addition, in the case of laminated nonwoven fabrics, Example Material 8 is useful as a reference. That is, in a vertical piping test, the first layer (layer without SAF) was arranged on the outside and the second layer (layer with SAF) was arranged on the inside (arrangement (A)). In the arrangement (A) where the first layer was the outer layer, the weight was 11.5 g, while in the inverted arrangement, the weight was 14.3 g, with improvement rates of 76.0% and 70.2%, respectively. From these results, it was observed that the arrangement (A) where the first layer was the outer layer tended to be slightly better than the arrangement (B) where the first layer was on the inside and the second layer was on the outside.

[0084] (Application of the thermal insulating cover member to other heat exchanger piping covering members) The application examples of the thermal insulating cover member of the present invention to other thermal insulating cover members will be described. Examples of applications include creating a joint covering member to cover the gap between thermal insulating cover members and using it as a joint covering member, using the thermal insulating cover member as an elbow covering member for the bent portion of a heat exchanger piping, and using it as a covering member for an existing piping cover that is wrapped around an existing piping. Therefore, the thermal insulating cover member of the present invention was manufactured and used for the purpose of being used in these members, and the structure of these members will be described.

[0085] Based on the experimental results of the present invention, we fabricated a joint covering member (insulating cover member) 65 that can be placed to cover the gap between a predetermined insulating cover member and an adjacent insulating cover member arranged longitudinally of the piping (see FIG. 10 ). This joint covering member has an adhesive layer 63 on one side of a foam opposite the nonwoven fabric 3, a release sheet 62 attached thereto, and a nonwoven fabric covering the other side of the foam. The nonwoven fabric contains a predetermined amount of superabsorbent polymer fibers (not shown). Figure 11 shows two piping structures 10 arranged continuously in the longitudinal direction. A thin seam 66 is formed between these piping structures. In this embodiment, the seam is fixed by wrapping the joint covering member (adhesive-attached insulating cover member) 65 shown in FIG. 10 around the joint. This prevents condensation at the joint not covered by the covering member and also prevents or suppresses the dripping of condensed water at this area.

[0086] Elbow Covering Member Figure 12 is a front view of one embodiment of an elbow covering member (bent joint) 25. The hatched areas are coated with adhesive or glue. This bent joint includes, for example, a narrow pipe housing section 22 and a thick pipe housing section 23. Refrigerant piping is placed in these pipe housing sections 22 and 23, and an elbow, a 90° bent refrigerant piping bending member, is installed in the elbow housing section 26 between them. The elbow covering member is produced by press-molding a sheet-shaped thermal insulation cover member for preventing or suppressing dripping of condensation water. The press-molding reduces the thickness of the thermal insulation cover member by 1-2 mm depending on the molded portion. However, the resulting finer bubbles result in little change in thermal insulation performance. When the product is in use, the bent section 24 is folded in a valley fold, and the adhesive coated on the surface of the branch section 28 (split member) is butted against and fixed to the branch section 28 (split member) so that the two halves are butted together. Although not shown in the figures, the elbow covering member of the present invention uses a foam surface as the surface that comes into contact with the piping and the nonwoven fabric surface of the present invention as the outer surface of the elbow covering member, so that a nonwoven fabric containing highly water-absorbent resin fibers is disposed on the surface of the elbow covering member (bent joint) 25. Note that the elbow covering member can also achieve the same effect in suppressing or preventing dripping of condensation water as the heat-insulating cover member for preventing or suppressing dripping of condensation water that covers the outer periphery of straight heat exchanger piping.

[0087] Cheese Element Covering Member Figure 13 is a front view showing a schematic diagram of one embodiment of a cheese element covering member 78. The cheese element covering member 22 has a generally T-shape that is symmetrical above and below the bent portion 24, resulting in a generally cross-shaped overall configuration. The cheese element covering member 78 has a larger pipe diameter in the cheese element housing portion 77 than in the pipe housing portion 22 connected to the cheese element, and the wall thickness near the center where the T-shaped branch is thicker, resulting in a double T-shape. Similar components include elbow covering members used at bends and cheese elements that branch straight piping into a T-shape. A cheese element is a metal member that branches downward or upward from the straight portion corresponding to the head of the T-shape. Although the state in which this cheese member is covered with a cheese member covering member is not particularly shown, this cheese member, like the elbow covering member, can also be formed with a T-shaped head portion as bent portion 24, a branch portion branching off downward or upward, and the entire branch portion surrounded by bent portion 24 and branch portion 28 (half-split member), with the bent portion serving as a hinge for opening. Here, with regard to suppressing or preventing dripping of condensation water, cheese member covering member 78 can also achieve the same effect as a heat-insulating cover member for preventing or suppressing dripping of condensation water that covers the outer periphery of straight heat exchanger piping.

[0088] Covering Member for Existing Conventional Pipe Covers Figure 14 is a cross-sectional view of a covering member 68 for covering an existing pipe cover, in which a resin foam covering a refrigerant pipe is double-wrapped with a film separating it. Regarding the piping structure of this embodiment, from the center of the cross-sectional circle, the refrigerant pipe 1 is located at the innermost position, and the resin foam 2 of the existing conventional pipe cover 76 covers it. The existing conventional pipe cover 76 is structured such that the resin foam 2 is covered with a resin film 27 such as PE. In a structure using PE film for this foam, PE film does not retain water, so condensation occurs depending on the environmental conditions around the pipe, and this condensation is prone to dripping. Furthermore, the resin foam 2 covers the outside of the resin film 27, and then the nonwoven fabric 3 covers the outermost layer. In other words, the resin foam 2, resin film 27, resin foam 2, and nonwoven fabric 3 together constitute a covering structure using the covering member 68 for covering the existing conventional pipe cover 76. By further covering such an existing conventional pipe cover 76 with a cover member having a nonwoven fabric 3 containing a superabsorbent polymer disposed on the foam surface, it becomes possible to prevent or suppress dripping of condensed water. In this embodiment, an adhesive layer 63 (thickness of the layer is not shown) is disposed on the back surface of the portion of the outermost nonwoven fabric 3 of the upper resin foam extending from the foam. Furthermore, a film-like release sheet 62 is attached to the back surface of the adhesive layer 63, and this release sheet 62 can be peeled off to adhere to the resin foam 2. The covering member 68 shown in the figure to be covered with the conventional pipe cover can be applied to a refrigerant pipe covered with the existing conventional pipe cover 76 to prevent or suppress dripping of condensed water. Specifically, the covering member 68 to be covered with the conventional pipe cover 76 shown in FIG. 14 has gaps 69, and the thermal insulation cover member can be opened like a double door at these gaps and then attached to the existing pipe. The nonwoven fabric 3 extending from one end of the covering member 68 to be placed over the conventional piping cover 76 has an adhesive layer 63 attached, and can be wrapped around the covering member while adhering after peeling off the release sheet 62. This nonwoven fabric 3 uses a heat-insulating cover member for preventing or suppressing dripping of condensation water, and therefore contains the same amount of superabsorbent resin fiber (not shown) as in the present invention, and can therefore exhibit the effect of preventing or suppressing dripping of condensation water.

[0089] (Application of Thermal Covering Members to Duct Covering Members and Covering Structures) Water vapor can condense on the outer surface of a metal duct for a heat exchanger having a generally rectangular cross section, causing water droplets to drip down the surface of the duct. In response to this, Figure 15 shows an embodiment in which a thermal covering member according to the present invention is applied to a metal (particularly iron) duct 67 as a duct covering member 70. Specifically, a pressure-sensitive adhesive or adhesive layer (not shown) is provided on the side of the resin foam 2 opposite the nonwoven fabric 3, and the thermal covering member is attached to the iron duct 67 as a duct covering member 70 via this pressure-sensitive adhesive layer. Here, the nonwoven fabric 3 contains highly absorbent resin fibers (not shown). In this case, the thermal covering member with adhesive is used as the duct covering member 70. Here, the duct covering member 70 may be wrapped around the corners of the duct 67, but in this case, since the corners cannot be wrapped with an even thickness, a sheet cut to a predetermined size corresponding to each side of the outer peripheral surface of the duct may be attached to each outer surface of the duct as the duct covering member 70. By doing so, the entire outer peripheral surface of the duct 67 can be covered with the heat-insulating cover member as the duct covering member 70. This makes it possible to obtain a duct covering structure in which the duct covering member 70 is attached to the outer peripheral surface of the duct. This is expected to have the effect of preventing or suppressing the dripping of condensation water.

[0090] (Application of the Thermal Cover Member to Electrical Equipment Box Covering Members and Covering Structures) Electrical equipment boxes 80 include cubicles, distribution boards, and panelboards that house equipment that receives and reduces the voltage of power from an external high-voltage power source and distributes it to required locations, as well as control panels that house electrical equipment for automatic control of machinery and equipment, and battery boxes that house batteries such as storage batteries. In the present invention, these are collectively defined as "electrical equipment boxes." While these electrical equipment boxes are exposed to temperature and humidity changes both indoors and outdoors, their interiors are designed to operate at high speeds due to the high integration of the housed equipment, which can lead to condensation due to heat generation. Electrical equipment boxes contain many components with high thermal conductivity, such as metal parts, which are susceptible to changes in outside temperature, increasing the risk of condensation. Condensation on ceiling surfaces in particular can drip onto the equipment, leading to malfunctions. Therefore, preventing condensation on ceiling surfaces is particularly important. Therefore, in order to prevent condensation inside the electrical equipment box, the thermal insulating cover member of the present invention can be applied to at least the back or front surface of the electrical equipment box 80 excluding the opening of the distribution panel, and particularly to prevent condensation on the ceiling surface, the inner surface of the box, and the internal space of the box, to prevent or suppress condensation inside the electrical equipment box. Therefore, using a distribution box with a thermal insulating cover member attached to the electrical equipment box and ceiling surface as an example, an electrical equipment box covering structure will be fabricated, and a comparative experiment will be conducted under test conditions (outside air temperature 20°C, humidity conditions inside the electrical equipment box 35°C-90% RH) between using the electrical equipment box as is without the thermal insulating cover member and using the thermal insulating cover member as a covering structure for the electrical equipment box. It is expected that this experiment will suppress condensation on the inner wall surface, ceiling surface, and surface of the steel plate of the electrical equipment box, or, even if condensation cannot be suppressed, significantly suppress the dripping of condensed water. Here, taking a distribution box as an example of an electrical equipment box 80, to explain more specifically, an AC load switch 87, a distribution board transformer 84, an ammeter 85, a voltmeter 86, a wiring circuit breaker (switch) 83, etc. are arranged on the inner surface of the iron box.The above-mentioned components of the distribution box are installed on an iron plate 88 inside the box and connected by appropriate wiring. To prevent condensation, a protective cover member 5 (resin foam 2, nonwoven fabric 3) is attached to the ceiling, inner walls, bottom, or the back or front (usually the back) of the iron plate on which various components are installed inside the distribution box to enhance insulation and prevent condensation. The plate inside the box is usually made of iron with a resin coating, but it may also be made of resin. Figure 16 shows a schematic diagram of an example of a distribution box, in which various components and devices, such as the AC load switch 87, distribution board transformer 84, ammeter 85, voltmeter 86, and molded case circuit breaker (switch) 83, are arranged and connected by appropriate wiring. A distribution box is typically a rectangular box-shaped structure, enclosed by a roof, an iron bottom plate, side walls, a base for elevation, and a rear panel, and has a door for opening and closing on the surface. If the wiring connecting the various components and devices is installed on the surface of the iron plate, there is no problem with placing a protective cover member on the back surface of the iron plate 88. On the other hand, if the various components and devices are placed in the openings of the iron plate and the wiring is placed on the back surface, it is desirable to place the protective cover member on the back surface of the iron plate 88 in advance before laying out the wiring so as not to obstruct the wiring.

[0091] The components of the electrical equipment box include 1) a high-voltage AC load break switch 87 (located in front of the plate), 2) a transformer (located without a plate: due to the large transformer volume) 84, 3) an ammeter (located in an opening in the plate) 85, 4) a voltmeter (located in an opening in the plate) 86, 5) a molded-case circuit breaker (located in an opening in the plate) 83, 6) a heat-insulating cover member 5, and 7) an electrical equipment box body 81. As described above, no iron plate 88 is installed in the transformer area, and an inverted L-shaped iron plate 88 with an opening 89 cut out on the lower left side in a plan view is installed in the area excluding the transformer. The high-voltage AC load break switch 87 is installed in front of the plate, and openings are formed in the iron plate 88, in which current and voltage meters 85 and 86 and various molded-case circuit breakers 83 are installed.

[0092] The effectiveness of the thermal cover member as a countermeasure against condensation in electrical equipment boxes can be summarized as follows. Condensation occurs when the surface temperature of the object being condensed and the absolute humidity of the temperature and humidity environment in which the object is placed are important factors. For example, when considering condensation on the inner surface of an electrical equipment box, if the temperature of the inner surface of the box is higher than the dew point, condensation will not occur even in a constant humidity environment. However, if the surface temperature drops below the dew point as the surface temperature drops, condensation will occur. Furthermore, the reduction in the surface temperature of the inner surface of the electrical equipment box can be prevented, and the increased surface area of ​​the nonwoven fabric 3 containing a highly absorbent polymer attached to the surface and the improved heat transfer coefficient due to water absorption combine to suppress condensation. Even if condensation does occur, it is expected that dripping of condensed water will be suppressed or reduced.

[0093] (Additional Notes on Materials, Test Results, and Other Information in Examples and Comparative Examples) Examples of the thermoplastic resin fibers include, for example, PP, PE, and PET fibers, or fibers with a core-sheath structure such as PET / PE or PP / PE. In the examples, test results were shown using a nonwoven fabric with a core-sheath structure such as PET / PE as the base resin for both single-layer and multi-layer nonwoven fabrics. However, in addition to the PET / PE core-sheath structure, a PP / PE core-sheath structure may also be used as the base resin. The reason for using fibers with a core-sheath structure is that it is desirable to use a high-melting-point PET or PP fiber for the core and a low-melting-point fiber such as PE for the sheath. While it is of course possible to use ordinary fibers that do not have a core-sheath structure, such as PP, PE, or PET, using a high-melting-point material for the core and a low-melting-point material for the sheath can enhance both the strength and fusibility of the nonwoven fabric. In other words, whether to use fibers with a core-sheath structure or ordinary fibers can be determined based on the usage situation.

[0094] The inventive example (inventive material) of the present invention, whether the nonwoven fabric laminated to the resin foam is a single layer or a multi-layer (two-layer) structure, has at least one nonwoven fabric layer containing superabsorbent resin fibers. This nonwoven fabric layer contains 10% to 80% superabsorbent resin fibers by mass, with the remainder containing 20% ​​to 90% thermoplastic resin fibers by mass, thereby achieving the desired moisture retention parameters and water retention. As a result, in a vertical piping condensation drip test, the inventive material demonstrated an improvement in condensation drip volume of more than 30% compared to the conventional material. Considering this as a threshold, the inventive material achieved a satisfactory result of drip volume of less than 33.6 g. Such excellent results were confirmed not only with Bell Oasis (inventive material examples 1-4, 6-10) but also with Lanseal (inventive material examples 5 and 11), regardless of the type of superabsorbent resin fiber. Furthermore, it was confirmed that not only when the nonwoven fabric is laminated (two layers) (invention example materials 6 to 11), but also when the nonwoven fabric is single layer (invention example materials 1 to 5), by including a predetermined amount of superabsorbent resin fiber, good results were obtained in the condensation water drip test under harsh temperature and humidity conditions using vertical piping with eyeglass-type piping.

[0095] Furthermore, when the nonwoven fabric has a laminated structure, the basic performance and condensation prevention / suppression test results of a laminated structure in which a first layer containing no superabsorbent polymer fibers is arranged as the outer layer and a second layer containing superabsorbent polymer fibers is arranged as the inner layer, and a structure in which this structure is inverted upside down so that the second layer containing superabsorbent polymer fibers is arranged as the outer layer and the first layer containing no superabsorbent polymer fibers is arranged as the inner layer, show that a cover member with a laminated structure in which the first layer containing no superabsorbent polymer fibers is arranged as the outer layer has better condensation prevention / suppression performance, and when comparing a laminated product with a single-layer product, the laminated product has better condensation prevention / suppression performance than the single-layer product. The difference in condensation prevention / suppression performance between the laminated product and the single-layer product is presumably due to the fact that the laminated structure, including the inverted structure, provides the laminated product with a first layer, which is a nonwoven fabric layer made of thermoplastic resin fibers that does not contain superabsorbent polymer fibers, which can provide the effect of widely diffusing condensation water, and further, the evaporation of condensation water is promoted by the first layer being arranged as the outer layer. In contrast, when the inverted second layer is positioned as the outer layer, it has some effect of diffusing condensation water that penetrates the second layer (the outer layer) and reaches the first layer, but the condensation water evaporation effect when the second layer is positioned as the outer layer is weak. Therefore, it is believed that a laminate with the first layer as the outer layer is more effective in preventing or suppressing dripping of condensation water than a laminate with the second layer as the outer layer. This can be understood from the fact that the evaporation effect when the first layer is positioned on the outer surface, as described in paragraph

[0075] , is greater than the evaporation effect when the second layer is positioned on the outer surface or in a single-layer product. Therefore, to prevent or suppress dripping of condensation water, it is important to balance the diffusion and evaporation effect of the nonwoven fabric and the water retention effect of the superabsorbent resin fiber. It is believed that an insulating cover member in which a nonwoven fabric with the first layer positioned on the outer surface and a resin foam body are laminated is most effective in preventing or suppressing dripping of condensation water.

[0096] Among the inventive materials, the moisture retention parameter and water retention tended to increase with increasing superabsorbent polymer fiber content. In a vertical piping condensation drip test, the condensation drip rate was found to be effective in preventing or suppressing dripping. Specifically, in a vertical piping condensation drip test, when the BELLOAS content was 10% by mass, the condensation drip rate was 32.5 g, but when the content increased to 75% by mass, it was reduced to 3.8 g. Furthermore, at a content of 25% or higher, the condensation drip rate in the vertical piping test was reduced to 0.8 to 23.3 g, or less than 24 g, representing an improvement rate of over 50%. Therefore, it is desirable to set the content rate of the superabsorbent polymer layer to 25% or higher. Figure 17 shows the time course of condensation drip rate for a representative example of the test material in a condensation drip test using a vertical piping system with a spectacle-shaped piping system and a temperature of 35°C and humidity of 90%. The test results, shown in Table 2, show the changes over time for Conventional Material 1 and Inventive Material 8 (containing 40% of the superabsorbent resin Belloasis). Comparing Conventional Material 1 and Inventive Material 8, Conventional Material 1 shows a tendency for condensation to rapidly progress after a little over six hours, while Inventive Material 8 does not produce any condensation until 11 hours, after which condensation does occur, but the tendency for condensation to increase is also weak. In contrast, although not specifically shown, in the case of horizontal piping, none of the Inventive Materials (Inventive Materials 1 to 11), including Inventive Material 8, produced any condensation, while Conventional Material 1 produced condensation even in the case of horizontal piping.

[0097] From the above results, it can be seen that the drip-preventing or drip-suppressing heat-insulating cover member of the present invention can effectively suppress or prevent condensation water from dripping from the piping surface in a piping structure to which it is applied, even when the refrigerant piping in an air conditioner or the like is vertical rather than horizontal. Therefore, the present invention can prevent water dripping from the refrigerant piping from accumulating in the attic or around vertical piping inside a room, which can lead to the growth of mold and bacteria and the rotting of wood, thereby deteriorating the living environment. It can be seen that, compared to conventional devices, deterioration of the living environment can be prevented and the soundness of the house can be maintained for a longer period of time.

[0098] The heat exchange piping covering component of the present invention has the effect of preventing condensation from dripping. That is, when the thermal insulating cover member of the present invention is used as a protective member for covering gaps between thermal insulating cover members, a thermal insulating cover member applied to a bent portion of heat exchange piping, or a covering member for covering an existing conventional piping cover that is wrapped around existing piping, it is expected to suppress the generation of condensation or prevent or suppress dripping of condensation even if it does form. Here, it is conceivable to use the thermal insulating cover member of the present invention as a protective member for covering joints, elbows, tee parts, and existing piping covers. In all of these applications, the structure in which the thermal insulating cover member for preventing or suppressing dripping of condensation, which is formed by bonding a nonwoven fabric to the surface of the resin foam of the present invention, is basically used as is, and further, it is used to cover gaps in the protective member as a heat exchange piping covering component or the outer periphery of an existing insulation structure using a foam, so that the same effect as the present invention can be expected. Strictly speaking, in the case of elbow coverings and tee-piece coverings, because the heat-insulating cover member for preventing or suppressing dripping of condensation water is press-molded, the apparent thickness of the cover member is approximately 20% thinner in some areas, but the air bubbles in those areas are finer, and it was found that there is no difference in thermal insulation. From the above, it was considered that the above-mentioned joint coverings, elbow coverings, tee-piece coverings, and coverings for existing piping covers all have the same condensation prevention or condensation suppression performance as the heat-insulating cover member for preventing or suppressing dripping of condensation water, in which a nonwoven fabric is bonded to the surface of the resin foam of the present invention. Here, it has been confirmed that these heat exchanger piping coverings have sufficient condensation prevention or suppression effects.

[0099] Consider the susceptibility of condensation to copper refrigerant pipes and metal (iron) ducts. For example, if we assume that the ambient temperature is the same for both, 23°C, and that the fluid temperature flowing through the refrigerant pipes is the same, steady-state temperature of 5°C, then both fluid temperatures are constant. Furthermore, since the cross-sectional direction of the ducts is similar, with a foam and a nonwoven fabric of a certain thickness containing highly absorbent polymer fibers attached to the surface, it is thought that the copper pipe and the duct will both have roughly the same surface temperature in terms of heat transfer in the cross-sectional direction, assuming that the same foam is used, including the thickness.

[0100] However, in this case, the temperature of the refrigerant flowing through the refrigerant pipe and the temperature of the air flowing through the duct are the same, and assuming that the temperature of the fluid flowing in the axial direction of the pipe is constant in a steady state, the temperature of the nonwoven fabric surface between the two will be equal. On the other hand, the temperature of the refrigerant flowing through the copper refrigerant pipe currently being considered is around 5°C, and the temperature of the air flowing through the duct is 13 to 17°C. In this case, the temperature of the air flowing through the duct is generally higher than the refrigerant flowing through the copper pipe, so heat transfer through the duct is less.

[0101] Furthermore, when comparing the thermal conductivity of copper, the material of the refrigerant pipe, and that of iron, the material of the duct, the latter has a lower thermal conductivity, resulting in a higher thermal resistance when both are approximately 1 mm thick. Therefore, the effect of the air temperature inside the duct on the surface temperature of the foam and nonwoven fabric covering the duct surface with respect to heat transfer from each fluid is smaller than that of a copper pipe covered with foam and nonwoven fabric. Consequently, the decrease in the surface temperature of the nonwoven fabric is smaller in the duct than in the copper pipe, and the duct covering structure has less effect on the surface temperature of the nonwoven fabric from the internal fluid than the copper pipe covering structure. Therefore, the evaluation results of the condensation test on the copper refrigerant pipe of the present invention suggest that the surface temperatures of the foam and nonwoven fabric in the duct are not too severe, but rather tend to be more moderate. Therefore, when evaluating condensation occurrence and dripping, it is believed that the trends in the test results of the thermal insulating cover member for preventing or suppressing dripping of condensation water of the present invention can be directly applied.

[0102] To confirm this, test material 1, a single-layer nonwoven fabric (145 g / m ２The test material 6 is a two-layer laminated nonwoven fabric (the surface layer has a PET / PE weight of 18 g / m2) with a SAF blending ratio of 10%. ２ The weight of the second layer containing SAF is 30 g / m ２ A rectangular duct measuring 10 cm wide x 10 cm high x 30 cm long was created using test materials 1 and 6, which had the lowest SAF content (10% SAF content) as invention products. The foam surface of the test material was attached to the duct with an adhesive so that the nonwoven fabric side of the test material was positioned on the surface of the duct, resulting in a structure in which the entire surface of the duct was covered with the test material. This structure was installed so that the air flow was vertical, and the air temperature within the duct was adjusted to a lower limit of 13°C ± 1°C. A condensation test was conducted under a harsh environment of 35°C and 90% humidity. Results were comparable to or better than those for copper pipe, as shown in Table 2. The results confirmed that the duct cover also provided sufficient condensation prevention and suppression effects. In this case, it is clear from Table 1 that the nonwoven fabric has a moisture retention parameter of 0.70 or more, which means that the nonwoven fabric retains moisture against gravity, and a moisture retention capacity of 7.0 g or more, as determined under specified conditions.

[0103] The effectiveness of the thermal cover member as a measure against condensation in electrical equipment boxes can be summarized as follows. Condensation depends on the surface temperature of the object that is the target of condensation and the absolute humidity in the temperature and humidity environment in which the object is placed. For example, when considering condensation on the inner surface of an electrical equipment box, if the temperature of the inner surface of the box is high, condensation will not occur even in a constant humidity environment. However, condensation will occur if the surface temperature drops below the dew point as the surface temperature drops. However, when the protective cover of the present invention is used, the insulating effect of the resin foam that constitutes the lower part of the protective cover can prevent a drop in the surface temperature of the inner surface of the electrical equipment box. At the same time, the water absorption effect of the nonwoven fabric containing superabsorbent resin fibers attached to the surface and the reduced thermal resistance of the nonwoven fabric due to the increased surface area of ​​the superabsorbent resin fibers due to water absorption combine to provide an expected effect of suppressing or preventing condensation. As already explained, taking into account radiative cooling in the summer, tests were conducted under somewhat harsh conditions, with an outside air temperature of 20°C and temperature and humidity conditions inside the electrical equipment box of 35°C-90% RH, with and without the cover member of the present invention. The outside air temperature outside the electrical equipment box was about 20°C, while the air temperature inside the duct in the case of a duct was about 13°C higher. Even if the temperature of the electrical equipment box became slightly supercooled below the outside air temperature due to radiative cooling, the insulating effect of the resin foam that constitutes the insulating layer of the thermal cover member, the water retention effect of the nonwoven fabric containing highly water-absorbent resin fibers on the surface of the resin foam, and the transpiration effect of the base resin fibers of the nonwoven fabric all combine to produce a test that is likely to significantly reduce the dripping of condensation water, even if condensation occurs on the inside surface of the equipment box or the backside of the steel plate. Here, the condensation generation and dripping confirmation test for the electrical equipment box was conducted using test material 1 (basis weight 145 g / m) for a single-layer product, as in the case of a duct. ２ The two-layer laminate was test material 6 (the surface layer PET / PE weight was 48 g / m ２The test was carried out using the test material with the lowest SAF content (10%). As a result, evaluation results equivalent to or better than the test results for copper pipe shown in Table 2 were obtained. As described above, it was confirmed that the heat-insulating cover member of the present invention also has a sufficient effect of preventing and suppressing condensation when used as a cover member for an electrical equipment box. From the above, it was confirmed that the heat-insulating cover member of the present invention can be used as a covering member for an electrical equipment box by placing it on the inner wall surface of the electrical equipment box or, if necessary, on the panel surface.

[0104] Here, the present invention uses the term "prevention or suppression of dripping of condensation water" rather than "prevention of dripping of condensation water." This is because, while it is possible to prevent dripping of condensation water in a normal usage environment, it is impossible to know what kind of harsh environment will be encountered at an actual construction site. Furthermore, even if an installation environment corresponding to the harsh temperature and humidity conditions of the condensation drip prevention test conducted this time is not encountered, various temperature and humidity conditions are anticipated. Furthermore, even if the actual installation environment is not a harsh environmental condition, the temperature and humidity conditions will fluctuate over time, which poses a problem that it is not always possible to make a perfect comparison with the installation environment at each site. Therefore, based on this consideration, the present application deliberately uses the term "prevention or suppression of dripping of condensation water" rather than "prevention of dripping of condensation water" in the purpose and problem of the present application. Furthermore, in a severe temperature and humidity environment test using a thermo-hygrostat chamber and vertical piping with eyeglass-shaped piping, it was confirmed that a cover member containing the superabsorbent polymer fiber of the present invention at a blend ratio of 10% to 80% had an improvement in the amount of condensation water generated by at least 30% compared to Conventional Material 1 (a currently used product: a product in which a polyethylene film is laminated to the surface of a foam) in the test shown in Table 2, and that a blend ratio of superabsorbent polymer fiber of 25% to 80% had an improvement of 50% or more. From the above, looking at the test results of the present invention, it is clear that the material of the present invention is able to significantly suppress the dripping of condensation water, at least in severe environments, compared to the conventional material and the comparative material, and that it can achieve either prevention or suppression of dripping of condensation water in actual usage environments.

[0105] DESCRIPTION OF SYMBOLS 1 Refrigerant piping 11 Pipe 12 Drain pipe 13 Wiring piping 2 Resin foam 21 Air bubbles 22, 23 Pipe storage section 24 Bending section 25 Elbow covering member (bent joint) 26 Elbow storage section 27 Resin film 28 Branching section 3 Nonwoven fabric 31 First nonwoven fabric layer 32 Second nonwoven fabric layer 35 Thermoplastic resin fiber 36 Superabsorbent resin fiber 5 Heat-insulating cover member 6 Cavity, flow path 10, 20, 30, 40 Piping structure 41 Test piece 42 Water droplet migration range 43 Amount of water droplet migration above 44 Amount of water droplet migration below 51 Container 52 Water 53 Measure (electronic balance) 62 Release sheet 63 Adhesive layer 65 Seam covering member 66 Seam 67 Metal duct (iron duct) 68 Covering member to be placed over an existing conventional piping cover 69 Gap 70 Duct covering member 71 Indoor unit side piping 72 Outdoor unit side piping 73 Intermediate piping 75 Measure (electronic balance) 76 Conventional piping cover 77 Tee member housing section 78 Tee member covering member 80 Electrical equipment box 81 Electrical equipment box body 83 Switch 84 Transformer 85 Ammeter 86 Voltmeter 87 AC load break switch 88 Iron plate 89 Opening 100 Water retention test material

Claims

1. A heat-insulating cover member for preventing or suppressing dripping of condensation water, comprising a nonwoven fabric disposed on the surface of a resin foam, the resin foam being a polyethylene-based resin foam having closed cells, the nonwoven fabric being fixed to one surface of the resin foam by fusion or adhesion, the nonwoven fabric being composed of a single layer of nonwoven fabric in which a predetermined amount of thermoplastic resin fiber is mixed with superabsorbent resin fiber, and at least a portion of the thermoplastic resin fibers are fused or adhered to each other, the nonwoven fabric containing 10% to 80% by mass of the superabsorbent resin fiber, and the remainder containing 20% ​​to 90% by mass of the thermoplastic resin fiber.

2. The fiber diameter of the thermoplastic resin fiber used in the nonwoven fabric is in the range of 5 to 30 μm, the product thickness of the nonwoven fabric is 0.5 to 2.0 mm, and the basis weight of the nonwoven fabric is 30 to 300 g / m ２ 2. The heat-insulating cover member for preventing or suppressing dripping of condensation water according to claim 1 .

3. A thermal insulation cover member for preventing or suppressing dripping of condensation water as described in claim 1, characterized in that the thermoplastic resin fiber which is the base resin fiber of the nonwoven fabric is made of a single fiber of polyethylene terephthalate, polyethylene, or polypropylene, or a core-sheath structure fiber of these, or a fiber in which any of these fibers is mixed with other fibers, the nonwoven fabric is made of at least a portion of the thermoplastic resin fibers fused or bonded to each other, and the polyethylene-based resin foam contains a flame retardant.

4. The moisture retention parameter of the nonwoven fabric, which retains moisture against gravity, is 0.70 or more, and the moisture retention capacity of the nonwoven fabric determined under specified conditions is 7.0 g or more, and the moisture retention parameter is a parameter obtained by dividing the average value of the upward ascending distance from the mark line of the test specimen to the point where the test liquid reaches upward from the mark line of the test specimen, which is an index value using the ascending distance of the test specimen from the mark line and the descending distance of the test specimen from the mark line, in the width direction of the test specimen, after providing a mark line across the width direction at the midpoint of the longitudinal direction of a rectangular test specimen having dimensions of 200 mm length x 25 mm width, and holding the test specimen horizontally and dripping 400 μL of colored test liquid onto the mark line, and holding the test specimen vertically for 5 minutes immediately after the dripping, by the average value of the downward descending distance of the test specimen from the mark line to the point where the test liquid reaches downward, in the width direction of the test specimen, The heat-insulating cover member for preventing or suppressing dripping of condensation water according to claim 1, further characterized in that the water retention capacity is determined by inserting a refrigerant pipe having a length of 150 mm and a diameter of 25 mm, with the heat-insulating cover member attached to the outer periphery of the refrigerant pipe, into a container containing 20 g of water, and then retaining the container in a thermo-hygrostat at a temperature of 23°C and a humidity of 30% for 6 hours, after which the container is removed and the water is removed, and the water retention capacity is determined from the mass after the water removal.

5. A heat-retaining cover member for preventing or suppressing dripping of condensation water, comprising a nonwoven fabric disposed on the surface of a resin foam, the resin foam being a polyethylene-based resin foam having closed cells, the nonwoven fabric being fixed to one surface of the resin foam by fusion or adhesion, the nonwoven fabric being a laminated nonwoven fabric having a two-layer laminated structure, the first layer of the nonwoven fabric being composed only of thermoplastic resin fibers, at least a portion of the thermoplastic resin fibers being fused or adhered to each other, the second layer of the nonwoven fabric being composed of a nonwoven fabric in which a predetermined amount of thermoplastic resin fibers is mixed with superabsorbent resin fibers, at least a portion of the thermoplastic resin fibers being fused or adhered to each other, the nonwoven fabric of the second layer containing 10% by mass or more and 80% by mass or less of superabsorbent resin fibers relative to the total mass of the nonwoven fabric constituting the second layer, and further containing 20% ​​by mass or more and 90% by mass or less of the thermoplastic resin fibers as the remainder, either the first layer or the second layer of the nonwoven fabric being joined to the surface of the resin foam. A heat-insulating cover member for preventing or suppressing dripping of condensation water, comprising:

6. The total thickness of the first and second layers of the nonwoven fabric is 0.5 to 2.0 mm, and the total basis weight of the first and second layers is 30 to 300 g / m ２ The heat-insulating cover member for preventing or suppressing dripping of condensation water according to claim 5, characterized in that the thickness and basis weight of the nonwoven fabric of the first layer are smaller than the thickness and basis weight of the nonwoven fabric of the second layer, and the fiber diameter of the thermoplastic resin fiber used in the nonwoven fabric of the first layer or the second layer is in the range of 5 to 30 μm.

7. The total thickness of the first and second layers of the nonwoven fabric is 0.5 to 2.0 mm, and the total basis weight of the first and second layers is 30 to 300 g / m ２ The thickness of the nonwoven fabric of the first layer is 0.1 to 0.5 mm, and the basis weight of the first layer is 5 to 50 g / m ２ and the weight of the second layer is 25 to 250 g / m ２ The heat-insulating cover member for preventing or suppressing dripping of condensation water according to claim 5, characterized in that the thickness of the nonwoven fabric of the second layer is 0.4 to 1.5 mm, the thickness and basis weight of the nonwoven fabric of the first layer are smaller than the thickness and basis weight of the nonwoven fabric of the second layer, and the fiber diameter of the thermoplastic resin fiber used in the nonwoven fabric of the first or second layer is in the range of 5 to 30 μm.

8. A thermal insulation cover member for preventing or suppressing dripping of condensation water as described in claim 5, characterized in that the thermoplastic resin fiber, which is the base resin fiber of the nonwoven fabric, is made of either a single fiber of polyethylene terephthalate, polyethylene, or polypropylene, or a core-sheath structure fiber of these, or a fiber in which any of these fibers is mixed with other fibers, the nonwoven fabric is made of at least a portion of the thermoplastic resin fibers fused or bonded to each other, and the polyethylene-based resin foam contains a flame retardant.

9. The moisture retention parameter of the nonwoven fabric, which retains moisture against gravity, is 0.70 or more, and the moisture retention capacity of the nonwoven fabric determined under specified conditions is 7.0 g or more, and the moisture retention parameter is a parameter obtained by dividing the average value of the upward ascending distance from the mark line of the test specimen to the point where the test liquid reaches upward from the mark line of the test specimen, which is an index value using the ascending distance of the test specimen from the mark line and the descending distance of the test specimen from the mark line, in the width direction of the test specimen, after providing a mark line across the width direction at the midpoint of the longitudinal direction of a rectangular test specimen having dimensions of 200 mm length x 25 mm width, and holding the test specimen horizontally and dripping 400 μL of colored test liquid onto the mark line, and holding the test specimen vertically for 5 minutes immediately after the dripping, by the average value of the downward descending distance of the test liquid from the mark line of the test specimen in the width direction, The heat-insulating cover member for preventing or suppressing dripping of condensation water according to claim 5, further characterized in that the water retention capacity is determined by inserting a refrigerant pipe having a length of 150 mm and a diameter of 25 mm, with the heat-insulating cover member attached to the outer periphery of the refrigerant pipe, into a container containing 20 g of water, retaining the container in a thermo-hygrostat at a temperature of 23°C and a humidity of 30% for 6 hours, removing the container, and removing the water from the container, and determining the water retention capacity from the mass after the water removal.

10. A covering member for joints that can be arranged to cover a gap between an insulation cover member and an insulation cover member arranged adjacent to it in the longitudinal direction of a pipe when a pipe is covered with the insulation cover member for preventing or suppressing dripping of condensation water as described in any one of claims 1 to 9, wherein the covering member for joints has a release paper bonded to the adhesive on one side of a foam and a nonwoven fabric bonded to the other side of the foam, and the adhesive layer is bonded to the outer periphery of the insulation cover member with the surface of the nonwoven fabric bonded to the foam forming the outer periphery, thereby making it possible to prevent or suppress dripping of condensation water by using the covering member for joints.

11. An elbow covering member capable of preventing or suppressing dripping of condensation water by covering the elbow portion of the 90° bend or the vicinity of the 90° bend where the piping is directly bent 90°, with the surface of the member bonded to the nonwoven fabric foam as the outer surface, which can be obtained by folding the heat-retaining cover member for preventing or suppressing dripping of condensation water as set forth in any one of claims 1 to 9 in a back-to-back shape of a predetermined size so as to cover the 90° bend of the piping, and then press-molding the member into a substantially L-shape.

12. A tee member is a metal piping member that branches off downward or upward from a portion equivalent to the straight head portion of a T-shape, and has a branch portion that branches off downward or upward with the T-shaped head portion as a bending portion so that the tee member can be covered with a heat-insulating cover member for preventing or suppressing dripping of condensation water as described in any one of claims 1 to 9, and when the bending portion is folded with the bending portion as a hinge starting point for opening, the bending portion and the branch portion surround the entire tee member, thereby forming a tee member covering structure that can prevent or suppress dripping of condensation water.

13. A covering member to be placed on an existing conventional piping cover, characterized in that the covering member for covering existing piping having a polyethylene film bonded to its surface as described in any one of claims 1 to 9 is wrapped around a heat exchanger piping in an approximately cylindrical shape so that both ends face each other in the center, and the insulating cover member is further wrapped around the outer surface of the covering member to be placed on the existing conventional piping cover so that both ends face each other with the nonwoven fabric surface as the outer surface, thereby making it possible to prevent or suppress the dripping of condensation water.

14. A duct covering member capable of covering the outer surface of a duct with a heat-retaining cover member for preventing or suppressing dripping of condensation water as claimed in any one of claims 1 to 9.

15. A piping structure including at least any one of horizontal piping, oblique piping, vertical piping and curved piping, in which a heat-insulating cover member for preventing or suppressing dripping of condensation water as described in any one of claims 1 to 9 is covered around the outer periphery of the refrigerant piping, characterized in that the refrigerant piping is covered with each of the heat-insulating cover members for preventing or suppressing dripping of condensation water, with the outer surface being the surface of the single-layer nonwoven fabric or the surface of the first layer or second layer of a nonwoven fabric of a laminated structure.

16. A piping structure including at least any one of horizontal piping, oblique piping, vertical piping and curved piping in an eyeglass-shaped cross-section piping in which the outer periphery of each of two refrigerant pipes is covered with a heat-insulating cover member for preventing or suppressing dripping of condensation water as described in any one of claims 1 to 9, and the heat-insulating cover members are heat-sealed or bonded to each other, wherein the outer periphery of each refrigerant pipe of the piping structure is covered with either the surface of the single layer of nonwoven fabric of the heat-insulating cover member for preventing or suppressing dripping of condensation water or the surface of the first layer or the second layer of the nonwoven fabric of a laminated structure, and the refrigerant pipes are faced to each other and the outer surfaces of the nonwoven fabrics are heat-sealed or bonded to each other, thereby integrating the two pipes into an eyeglass-shaped configuration.

17. A piping structure including at least any of horizontal piping, diagonal piping, vertical piping and bent piping, in which one or more refrigerant pipes, drain pipes and wiring or wiring pipes are provided, and the one or more refrigerant pipes, drain pipes and wiring or wiring pipes are stored inside a thermally insulated cover member for preventing or suppressing dripping of condensation water as described in any of claims 1 to 9, wherein the surface of the single-layer nonwoven fabric or the surface of the first layer or second layer of a nonwoven fabric of a laminated structure is used as the outer surface, and the outer peripheral surface shape of the thermally insulated cover member for preventing or suppressing dripping of condensation water has a cross-sectional shape that is approximately cylindrical, and the refrigerant pipes, drain pipes and wiring or wiring pipes are surrounded by the thermally insulated cover member for preventing or suppressing dripping of condensation water so that they can be stored inside the thermally insulated cover member for preventing or suppressing dripping of condensation water, thereby storing components to be installed in the pipes inside the thermally insulated cover member for preventing or suppressing dripping of condensation water.

18. A covering structure using a heat-retaining cover member for preventing or suppressing dripping of condensation water on a duct for a heat exchanger, characterized in that the entire outer surface of an iron duct for a heat exchanger having a substantially rectangular cross-section is covered with a heat-retaining cover member for preventing or suppressing dripping of condensation water as described in any one of claims 1 to 9 so as to cover the outer periphery of the entire outer surface.

19. A covering structure for an electrical equipment box which receives power from an external power source and distributes or splits the received power to necessary equipment, characterized in that a heat-retaining cover member for preventing or suppressing dripping of condensation water as described in any one of claims 1 to 9 is disposed on at least one of the inner surface including the ceiling surface of the electrical equipment box, or the back or front surface of the distribution panel excluding the opening of the distribution panel.

20. A nonwoven fabric comprising a thermoplastic resin fiber and a specified amount of superabsorbent resin fiber, the nonwoven fabric has a water retention parameter of 0.70 or more for retaining water against gravity, and a water retention capacity of 7.0 g or more as determined under specified conditions, the product thickness of the nonwoven fabric being 0.5 to 2.0 mm, and the basis weight of the nonwoven fabric being 30 to 300 g / m ２ wherein the nonwoven fabric is made by mixing a predetermined amount of superabsorbent resin fibers with thermoplastic resin fibers having a fiber diameter in the range of 5 to 30 μm, at least a portion of which is fused or bonded to each other, the nonwoven fabric containing 10% by mass or more and 80% by mass or less of superabsorbent resin fibers relative to the total mass of the nonwoven fabric, and the remainder containing 20% ​​by mass or more and 90% by mass or less of the thermoplastic resin fibers, the retention force parameter being measured by providing a mark line across the width direction on the surface of a rectangular test piece having dimensions of 200 mm in length and 25 mm in width at a midpoint in the longitudinal direction, dropping 400 μL of a colored test liquid onto the mark line while the test piece is held horizontally, and immediately after dropping, holding the test piece vertically for 5 minutes, a parameter obtained by dividing the average value of the upward ascending distance from the marked line of the test piece to the point where the test liquid reaches, in the width direction of the test piece, which is an index value using the upward distance from the marked line of the test piece and the downward distance from the marked line of the test piece, by the average value of the downward distance from the marked line of the test piece to the point where the test liquid reaches, in the width direction; and further, the water retention capacity is the water retention capacity obtained by inserting a refrigerant tube having a length of 150 mm and a diameter of 25 mm, the outer periphery of which is attached with the heat-insulating cover member, into a container containing 20 g of water, retaining the container in a thermo-hygrostat at a temperature of 23°C and a humidity of 30% for 6 hours, removing the container, and removing the water from the container, and determining the water retention capacity from the mass after the water removal.

21. A nonwoven fabric comprising a thermoplastic resin fiber and a predetermined amount of superabsorbent resin fiber, the nonwoven fabric having a water retention parameter of 0.70 or more for retaining water against gravity and a water retention capacity of 7.0 g or more as determined under predetermined conditions, the nonwoven fabric being a laminated structure nonwoven fabric having a first layer and a second layer of nonwoven fabric, the thickness of the entire nonwoven fabric being 0.5 to 2.0 mm, and the basis weight of the entire nonwoven fabric being 30 to 300 g / m ２ Furthermore, the thickness of the nonwoven fabric of the first layer is 0.1 to 0.5 mm, and the basis weight of the nonwoven fabric of the first layer is 5 to 50 g / m ２ the thickness and basis weight of the nonwoven fabric of the first layer are smaller than the thickness and basis weight of the nonwoven fabric of the second layer, the first layer of the nonwoven fabric is composed only of thermoplastic resin fibers having a fiber diameter in the range of 5 to 30 μm and at least a part of which is fused or bonded to each other, and the nonwoven fabric constituting the second layer uses the same thermoplastic resin fibers as the first layer as base fibers, the nonwoven fabric of the second layer is composed of a nonwoven fabric in which a predetermined amount of superabsorbent resin fibers is mixed with base resin fibers which are thermoplastic resin fibers having a fiber diameter in the range of 5 to 30 μm and at least a part of which is fused or bonded to each other, and the nonwoven fabric forming the second layer is a nonwoven fabric containing 10% by mass or more and 80% by mass of superabsorbent resin fibers with respect to the total mass of the fibers of the nonwoven fabric of the second layer, and the remainder being 20% ​​by mass or more and 90% by mass or less of the thermoplastic resin fibers, and the retention parameter is a dimension A mark line is provided on the surface of a strip-shaped test piece having a length of 200 mm and a width of 25 mm at a midpoint in the longitudinal direction, 400 μL of a colored test liquid is dropped on the mark line while the test piece is held horizontally in a vertical position for 5 minutes immediately after the dropping, and then the water retention amount is a parameter obtained by dividing the average value of the upward ascending distance from the mark line of the test piece to the point where the test liquid reaches upward, which is an index value using the ascending distance from the mark line of the test piece and the descending distance from the mark line of the test piece, in the width direction of the test piece, by the average value of the downward descending distance from the mark line of the test piece to the point where the test liquid reaches downward, in the width direction; and the water retention amount is a parameter obtained by inserting and holding a refrigerant tube having a length of 150 mm and a diameter of 25 mm, the refrigerant tube having the heat-insulating cover member attached to its outer periphery, into a container containing 20 g of water, and then holding the container in a thermo-hygrostat at a temperature of 23° C. and a humidity of 30% for 6 hours, and then removing the container, and removing the water from the container, and calculating the water retention amount from the mass after the water removal. A nonwoven fabric used as a heat-retaining cover material to prevent or suppress the dripping of condensation water.

22. A nonwoven fabric used in a thermal insulation cover member for preventing or suppressing dripping of condensation water as described in claim 20 or claim 21, characterized in that the thermoplastic resin fibers are either polyethylene, polypropylene, or polyethylene terephthalate fibers, or core-sheath structure fibers thereof, or fibers in which any of the above fibers are mixed with other thermoplastic resin fibers, and at least a portion of these resin fibers are fused or bonded to each other.

23. A method of using the laminated nonwoven fabric according to claim 20 or 21 as a heat-retaining cover member for preventing or suppressing dripping of condensation water, in which the resin foam is bonded to the surface of a polyethylene resin foam having closed cells, characterized in that the surface of the single-layer nonwoven fabric or either the first layer or the second layer of the laminated nonwoven fabric is faced outward, and the remaining layer of the layer facing outward is used as the bonding surface, and the nonwoven fabric and the resin foam are bonded to one surface of the resin foam so as to be fixed by fusion or adhesion.

24. A method for using an insulating cover member for preventing or suppressing dripping of condensation water as described in any one of claims 1 to 9 as a covering member for joints used in gaps between insulating cover members, an elbow covering member, a Tee member covering member, a covering member for covering an existing conventional piping cover, a duct covering member, or an electrical equipment box covering member, for preventing or suppressing dripping of condensation water, for various covering members including heat exchange piping covering members.

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