Heat insulating material for preventing dripping of condensation water, refrigerant piping and hot and cold water supply piping structure using the same, and building structure for preventing dripping of condensation water, nonwoven fabric for preventing dripping of condensation water, and method for forming a structure for preventing dripping of condensation water for refrigerant piping using the heat insulating material, and method for forming a structure for preventing dripping of condensation water for building components

Abstract

To provide a structure of a nonwoven fabric for condensation water dropping prevention, a heat insulator using the same, and its applications to a piping structure and a building structure.SOLUTION: A condensation water dropping-preventive heat insulator 3 has a nonwoven fabric 8 disposed on at least one surface of a polyethylene resin foam 7. The constituent fibers of the nonwoven fabric are at least partially fused or bonded to the surface of the polyethylene resin foam. The fiber has an average fiber diameter of 10-30 μm, the fiber has a voidage of 85-98%, and a 5% tensile stress value is 25 MPa or less and 1 MPa or more.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a heat insulating material for preventing dripping of condensation water, a refrigerant pipe and a water / hot water supply piping structure for preventing dripping of condensation water using the same, a building structure for preventing dripping of condensation water, a nonwoven fabric for preventing dripping of condensation water, a method for forming a structure for preventing dripping of condensation water for refrigerant pipes using the heat insulating material, and a method for forming a structure for preventing dripping of condensation water for building components. [Background technology]

[0002] Conventionally, a material obtained by laminating a polyethylene or polypropylene film to at least one surface of a polyethylene foam and then embossing the surface of the laminated resin foam has been used as a heat insulating material for piping for refrigerants in air conditioners, etc. However, in the case of such a heat insulating material, condensation occurs on the surface of the heat insulating material used around the periphery of the refrigerant piping, and this condensed water drips into the piping space above the ceiling, etc., causing the problem of mold growth in the piping space above the ceiling, etc.

[0003] Patent Document 1 describes a duct in which a nonwoven fabric is integrally molded with the duct body. The duct body is a foam blow-molded body. Because the nonwoven fabric is integrally molded with the duct body, which is a foam blow-molded body, condensation is less likely to occur on the surface of the duct body, and even if condensation does occur, the condensed water is absorbed by the nonwoven fabric, preventing the condensed water from dripping.

[0004] In the invention of Patent Document 1, the nonwoven fabric is integrally molded with the duct body, which prevents the nonwoven fabric from peeling off from the duct body. Because the nonwoven fabric is integrally molded with the duct body, the foam and the nonwoven fabric are not heat-sealed.

[0005] Patent Document 2 describes an air conditioning duct segment made of an inner layer of closed-cell foam and a nonwoven fabric made of a thermoplastic resin. The outer layer of this segment contains two types of thermoplastic resin with different melting points, and the resin layer with the lower melting point is bonded to the outer layer by fusion. The air conditioning duct segment is further formed with a structure in which the foam of the inner layer and the outer layer are bonded to each other with a hot melt adhesive that can bond at a temperature lower than the melting point of the lower-melting fiber of the two types of fibers that make up the outer layer.

[0006] This application also describes that the foam can be made of olefin-based thermoplastic resin foam such as polyethylene or polypropylene, or polyurethane foam, and that the nonwoven fabric can be made of thermoplastic resin fibers made of thermoplastic resin such as polyethylene, polypropylene, or polyethylene terephthalate, and that a core-sheath structure can be formed using resins with different melting points.

[0007] This application describes that the nonwoven fabric is a multi-layered nonwoven fabric having a core-sheath structure using two types of fibers, and further that the foam layer and the nonwoven fabric are bonded with a hot melt adhesive.

[0008] Patent Document 3 discloses a heat insulating material that is made by laminating a porous film and a nonwoven fabric, and that is characterized by absorbing water droplets dropped on the film surface within 60 seconds. The fibers of the nonwoven fabric can be general natural fibers such as cotton, linen, and wool, but the material is characterized by the use of some water-absorbent fibers. Because this heat insulating material is used for food, recycled fibers such as rayon and acetate are preferred, and from an economical standpoint, synthetic fibers such as polyethylene, polypropylene, and polyethylene terephthalate can also be used.

[0009] The feature of this invention is that the above-mentioned fibers contain, as water-absorbent fibers, fibers made of a crosslinked product of hydrophilic polyacrylic acid sodium salt in the range of 1 to 10%. Furthermore, the thickness of the nonwoven fabric is 0.3 to 3 mm (0.5 to 1.5 mm), and the basis weight of the nonwoven fabric is 20 to 250 g / m 2 It is described that the density is more preferably 50 to 150 g / m 2It is stated that:

[0010] Using a special water-absorbing resin improves the sheet's water retention capacity, but this increases costs, and because the nonwoven fabric base material is a resin film rather than a foam, there is also the problem of insufficient insulation.

[0011] Patent Document 4 discloses a method for forming an embossed sheet in which an embossed pattern is continuously engraved on a laminated sheet formed by bonding a resin foam sheet and a resin film. This invention discloses an embossing roll in which an embossing roll having adjacent recesses forming a pattern is pressed against the resin film and rotated, forming protrusions on the bottom surfaces of the recesses so that air pockets for collecting air are formed when the embossing roll is pressed against the sheet, and an embossed sheet manufactured using this embossing roll.Furthermore, this invention discloses a pipe cover characterized by being formed into a cylindrical shape so that the embossed pattern is located on the outer surface. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Publication No. 2020-197315 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-065382 [Patent Document 3] Japanese Patent Application Publication No. 9-300511 [Patent Document 4] Japanese Patent Application Publication No. 9-314661 Summary of the Invention [Problem to be solved by the invention]

[0013] It has been known that it may be possible to prevent condensation water from dripping by attaching a nonwoven fabric to the surface of a thermal insulation material. However, we have discovered that simply placing a nonwoven fabric on the surface is not enough to achieve a structure that prevents condensation water from dripping; regardless of the material of the nonwoven fabric, the nonwoven itself must have a specific structure. Therefore, our goal was to specifically identify such a structure. [Means for solving the problem]

[0014] In reality, the water absorption and condensation characteristics of a nonwoven fabric should differ depending on the material and structure of the nonwoven fabric, but there is no description regarding the structure and water absorption of the nonwoven fabric in the condensation drip prevention structures using nonwoven fabric in Patent Documents 1 and 2. Patent Document 3 uses a special water-absorbing resin such as a cross-linked product of sodium polyacrylate, but the present invention does not use such a resin and instead uses either a general-purpose resin chemical fiber material that does not have water absorption or a recycled fiber material that has water absorption, resulting in a heat-insulating material for preventing condensation dripping in which a nonwoven fabric having a predetermined structure is fused to the surface of a polyethylene resin foam that can prevent condensation dripping.

[0015] The heat-insulating material for preventing dripping of condensation water of the present invention is a polyethylene-based resin foam having a nonwoven fabric having a predetermined structure fused or adhered to at least one surface thereof. The present invention relates to a heat-insulating material for preventing dripping of condensation water, a refrigerant pipe and a hot and cold water supply pipe structure using the heat-insulating material, a building structure for preventing dripping of condensation water, a nonwoven fabric for preventing dripping of condensation water, a method for forming a structure for preventing dripping of condensation water for a refrigerant pipe using the heat-insulating material, and a method for forming a structure for preventing dripping of condensation water for a building member using the heat-insulating material.

[0016] Here, in order to prevent the dripping of condensation water in such a piping structure, by laminating a nonwoven fabric to a foam that is a heat-insulating material, it is possible to prevent the dripping of condensation water by holding the condensation water inside the nonwoven fabric. However, it was discovered that simply laminating a nonwoven fabric to the surface of a foam does not necessarily prevent the dripping of condensation water, and that the structure of the nonwoven fabric can prevent condensation in some cases and not in other cases. The three-dimensional structure of the fibers, such as the porosity of the nonwoven fabric, the degree of fiber bending, the structure of the fiber connections, and the entanglement of the fibers, has an effect on the dripping of condensation water. However, since the structure of nonwoven fabrics is complex, it is not possible to directly define this. However, the present invention was made by finding and defining an alternative parameter that reflects the effect of the complex structure of the nonwoven fabric on the dripping of condensation water.

[0017] In the present invention, the factors that determine the structure of the nonwoven fabric used in the heat insulating material are the fiber diameter of the nonwoven fabric used and the thickness of the nonwoven fabric at a predetermined thickness. Nonwoven fabric The researchers determined the spatial structure of the fibers based on factors such as the void ratio of the fibers, and also found that fibers with more bending parts and higher crimping properties have better condensation drip prevention properties. They also found that there is a correlation between the tensile modulus value at a specified strain in a tensile test, which is a parameter used to evaluate the three-dimensional structure including the crimping properties of the fibers, the structure of the fiber connections, and the degree of fiber entanglement, and the condensation drip prevention properties. The water retention properties based on the above structure were evaluated by evaluating the water retention capacity per specified nonwoven fabric thickness, and it was confirmed that nonwoven fabrics with a specified water retention capacity or more have excellent condensation drip prevention properties. Here, tensile modulus refers to the effective tensile stress value obtained by dividing the apparent tensile stress in a specified direction in a tensile test at a tensile elongation value of 5% in the same direction by the filling rate. Satisfying a specified tensile modulus value or effective tensile stress value means that the specified value is satisfied when the tensile modulus value or effective tensile stress value is greater than the specified value in a tensile test. MD This means that the effective tensile stress, which is the apparent tensile stress in the same direction at a tensile elongation of 5% divided by the filling ratio, satisfies a range of 25 MPa to 1 MPa. In other words, the tensile modulus and the effective tensile stress value are synonymous. Furthermore, the apparent tensile stress is the value obtained by dividing the apparent tensile load by the cross-sectional area of ​​the nonwoven fabric, which is defined by the apparent thickness of the nonwoven fabric measured in accordance with JIS L1913 and the width of the test piece.

[0018] Furthermore, the nonwoven fabric of the present invention is fused or adhered to an underlying polyethylene resin foam to form a thermal insulation material, and then embossed into a predetermined shape.Since it was thought that the shapeability during this embossing process would also be affected by the three-dimensional structure of the nonwoven fabric, particularly the filling rate and tensile modulus value, the shapeability during embossing was confirmed.

[0019] Furthermore, even if the fibers used in nonwoven fabrics are made of non-absorbent resins such as polyethylene resin, polypropylene resin, and PET, it is possible to increase water retention by making the nonwoven fabric satisfy certain structural conditions, and it was discovered that these fabrics also have excellent performance in preventing condensation water from dripping, which led to the creation of this invention.

[0020] Of course, as long as the nonwoven fabric satisfies certain structural requirements, it is also possible to use absorbent natural fibers such as cellulose and pulp, or regenerated or semi-synthetic fibers such as rayon and acetate, in a specified amount. In this case, the ability to prevent condensation from dripping is further improved compared to using non-absorbent resin fibers such as polyethylene resin, polyethylene resin, or polyester-based PET. However, the strength of the nonwoven fabric decreases, so the use of absorbent fibers must be limited to a specified amount within the total fiber weight. Furthermore, particularly when natural fibers such as cellulose and pulp are used in nonwoven fabrics, it is difficult to produce long fibers due to the characteristics of natural fibers, and fiber lengths are not stable, so it is desirable to use short fibers.

[0021] Since the present invention is guaranteed by the nonwoven fabric used for the thermal insulation material, in addition to the thermal insulation material for preventing dripping of condensation water, the piping structure for preventing dripping of condensation water using the same, and the building structure for preventing dripping of condensation water using the same, the present invention also includes the invention of the nonwoven fabric for preventing dripping of condensation water used therein, and the invention of the refrigerant piping structure using the thermal insulation material and the method of forming the structure for preventing dripping of condensation water for building components.

[0022] A heat-insulating material for preventing dripping of condensation water, in which a nonwoven fabric is disposed on the surface of a polyethylene-based resin foam, the substrate being a sheet-like polyethylene-based resin foam having closed cells, and the nonwoven fabric being fused or adhered to one surface of the substrate, The thickness of the nonwoven fabric measured in accordance with JIS L1913 is 1.0 mm or less, The average fiber diameter of the fibers constituting the nonwoven fabric is in the range of 10 to 30 μm, Nonwoven fabric The porosity of the fiber is 85-98%. The filling rate is 2 to 15%, Furthermore, the nonwoven fabric has an apparent stress in the MD direction at a tensile elongation value of 5% in the same direction in a tensile test. The aforementioned filling rate 2~15% This is a thermal insulation material for preventing condensation dripping, in which the effective tensile stress, calculated by dividing the effective tensile stress by the effective tensile stress, satisfies a range of 25 MPa to 1 MPa. It is sufficient that the effective tensile stress in the MD direction satisfies a range of 25 MPa to 1 MPa, while the effective tensile stress in the TD direction does not necessarily have to satisfy the range of 25 MPa to 1 MPa. Here, a thickness of at least 10 mm is sufficient for the polyethylene resin foam to ensure thermal insulation, so 10 mm is usually sufficient to obtain the desired thermal insulation performance. Conversely, if the foam is too thick, the product dimensions, such as the thickness and diameter of the product after coating with the thermal insulation material, will increase, so a thickness of 10 mm is desirable.

[0023] The reason why the average fiber diameter of the fibers is set to 10 to 30 μm is that if the fiber diameter is 10 μm or less, the strength of the nonwoven fabric will be insufficient, reducing the durability of the protective surface during use, and when the heat-insulating material is heat-sealed between the nonwoven fabric and the foam, the nonwoven fabric itself will deform, resulting in insufficient elastic recovery after fusion and the fibers will collapse and become planarly fused. Conversely, if the fiber diameter exceeds 30 μm, the increased fiber diameter will increase the space occupancy of the fibers themselves, making it difficult to form a three-dimensionally stable space with a high porosity, making it difficult to maintain a porosity in the range of 85 to 98%. Here, when the nonwoven fabric is composed of multiple fibers, the average fiber diameter referred to in the present invention is preferably such that the average fiber diameter of each constituent fiber satisfies the above range, but the average fiber diameter (number average) of those fibers will also satisfy the above range.

[0024] Regarding porosity, if the porosity is less than 85%, the proportion of fibers per unit volume becomes large, making it impossible to achieve sufficient water retention. On the other hand, if the porosity exceeds 98%, although the space for creating a water film increases, the water film cannot be maintained, resulting in a decrease in water retention, as well as a decrease in the shape stability of the nonwoven fabric itself and the elastic recovery of the nonwoven fabric after molding.

[0025] Furthermore, the tensile modulus (effective tensile stress) is calculated by dividing the normal tensile stress value by the filling rate, and therefore excludes the influence of the fiber filling rate (void fraction). This value is therefore considered to comprehensively include information on the crimping of the fibers themselves within the nonwoven fabric and the degree of fiber orientation within the nonwoven fabric. This is an important parameter because, assuming the same void fraction, the more crimped the fibers are and the less oriented they are, the smaller the distance between adjacent fibers in three dimensions, and therefore the more water the nonwoven fabric is likely to retain. In fact, an effective tensile stress exceeding 25 MPa is undesirable because it increases the rigidity of the nonwoven fabric and reduces its water retention, resulting in insufficient water retention and poor embossability. Furthermore, if the effective tensile stress in both the MD and TD directions is below 1 MPa, there is sufficient space to retain condensed water, but the bonding and entanglement of the fibers within the nonwoven fabric is insufficient, resulting in the loss of shape retention as a nonwoven fabric and making it difficult to handle in the manufacturing process of the present invention. Therefore, it is considered necessary for the effective tensile stress in at least one direction to exceed 1 MPa.

[0026] The thickness of the nonwoven fabric of the heat insulating material measured in accordance with JIS L1913 is 1.0 mm or less, and the water retention capacity converted to 1 mm of apparent thickness of the nonwoven fabric is 500 g / m 2 That's all be .

[0027] The fibers constituting the nonwoven fabric of the heat-insulating material may be composed of fibers containing at least one of PET resin, polyethylene resin, polypropylene resin, and acrylic resin. Furthermore, the fibers constituting the nonwoven fabric of the heat-insulating material may further contain cellulose, pulp, or rayon fibers in an amount of 30% or less of the total fiber weight. Furthermore, in terms of nonwoven fabric strength, the total fiber weight is preferably 15% or less. When using natural fibers, it is difficult to obtain long fibers, so it is preferable to use short fibers.

[0028] At least a part of the fibers constituting the nonwoven fabric of the heat insulating material is composed of fibers having a core-sheath structure, or the core fibers of the fibers having the core-sheath structure are hollow. Structure The hollow fiber is composed of a fiber having a core. Structure A multi-layered fiber in which a sheath portion is formed around the fiber, and the core-sheath fiber Sheath Or the hollow Structure The sheath of the fiber forming the core may be formed of a resin having a lower melting point than the core. By making the core hollow, the flexibility of the nonwoven fabric can be improved. The nonwoven fabric may be a nonwoven fabric in which at least a portion of the fibers constituting the nonwoven fabric are formed of short fibers, or formed of warp-to-warp orthogonal long fibers or warp-to-oblique long fibers.

[0029] Furthermore, the nonwoven fabric formed on the surface of the resin foam may be an embossed heat-insulating material for preventing dripping of condensation water. By performing the embossing process in this manner, the shape of the outer surface of the nonwoven fabric can be stabilized, and the shape stability of the nonwoven fabric when wrapped around a pipe, a duct, or the like can be improved.

[0030] The heat-insulating material for preventing dripping of condensation water is a heat-insulating material for preventing dripping of condensation water, which is made of a polyethylene-based resin foam and a nonwoven fabric, and the base material is a sheet-like polyethylene-based resin foam having closed cells, and the nonwoven fabric is fused to one surface of the sheet-like polyethylene-based resin foam, and the average fiber diameter of the fibers is in the range of 10 to 30 μm, and Nonwoven fabricThe insulation material may be a heat insulating material for preventing dripping of condensation water, in which the porosity of the fibers is 85 to 98%, and further, the effective tensile stress, which is the value obtained by dividing the apparent stress in the MD direction at a 5% tensile elongation value in the same direction by the filling rate in a tensile test, satisfies 25 MPa or less and 1 MPa or more, and further, the effective tensile stress, which is the value obtained by dividing the apparent stress in the TD direction at a 5% tensile elongation value in a tensile test by the filling rate, satisfies 25 MPa or less and 1 MPa or more.

[0031] That is, it is more desirable that the effective tensile stress value, obtained by dividing the apparent stress at 5% tensile elongation in the MD and TD directions in a tensile test by the filling rate, be 20 MPa or less and 1 MPa or more. More preferably, the effective tensile stress value, obtained by dividing the apparent stress at 5% tensile elongation in a tensile test in either the MD or TD direction by the filling rate, be 20 MPa or less and 2 MPa or more. By satisfying these characteristics, it is possible to obtain a thermal insulation material in which the effective tensile stress in both the MD and TD directions meets predetermined values, thereby obtaining a thermal insulation material that has excellent condensation drip prevention performance with little effect on directionality when the thermal insulation material is used, and therefore it is possible to prevent condensation dripping even when the thermal insulation material is used in a vertical direction.

[0032] The heat-insulating material for preventing dripping of condensation may be a pipe characterized in that the outer periphery of the refrigerant pipe or hot water pipe is covered with a nonwoven fabric toward the outer surface, thereby improving the heat retention of the pipe and preventing condensation.

[0033] This is a glasses-shaped piping structure in which two pipes are integrated by facing each other with heat-insulating materials to prevent condensation water from dripping, which are coated on the outer periphery of the refrigerant pipes, and heat-sealing or heat-bonding them together.

[0034] The present invention may be a cylindrical piping structure for refrigerant piping, characterized in that components to be installed inside a plurality of refrigerant pipes, drain pipes, and wiring are prepared, and the condensation-preventing heat-insulating material surrounds the plurality of refrigerant pipes, drain pipes, and wiring so that the nonwoven fabric-forming surface is the outer peripheral surface and the outer peripheral surface shape of the condensation-preventing heat-insulating material has a substantially cylindrical cross section, thereby storing the components to be installed inside the condensation-preventing heat-insulating material.

[0035] A cross-linked polyethylene pipe and a resin sheath pipe that covers the outer periphery of the cross-linked polyethylene pipe are provided as piping for supplying hot water and water, and the cross-linked polyethylene pipe and the resin sheath pipe that covers the outer periphery of the cross-linked polyethylene pipe are housed inside the condensation water drip-preventing insulation material so that the nonwoven fabric forming surface of the condensation water drip-preventing insulation material forms the outer periphery and the shape of the outer periphery of the condensation water drip-preventing insulation material has a cross-sectional shape that is approximately cylindrical.

[0036] The resin sleeve pipe may have a cylindrical piping structure for hot and cold water supply piping, in which the outer periphery of the sleeve pipe is covered with a resin foam so as to surround the outer periphery of the sleeve pipe.

[0037] The piping structure may be a vertical piping structure in which the condensation water drip prevention heat insulating material is wrapped around the outer periphery of a refrigerant pipe, and at least a part of the piping includes a vertical pipe, and the condensation water drip prevention heat insulating material is wrapped around the vertical pipe so that the nonwoven fabric forming surface of the vertical pipe is the outer periphery. Here, the condensation water drip prevention protective member wrapped around the vertical pipe has an average fiber diameter in the range of 10 to 30 μm, and Nonwoven fabric It is desirable that the nonwoven fabric has a fiber void ratio of 85 to 98%, and the apparent stress in the MD and TD directions at a tensile elongation of 5% divided by the filling rate is 20 MPa or less and 1 MPa or more.

[0038] The air conditioning duct may have a structure in which the heat-insulating material for preventing dripping of condensation is bonded to the outer surface of the air conditioning duct with the nonwoven fabric surface facing the outer surface. By covering the outer periphery of the air conditioning duct with the heat-insulating material for preventing dripping of condensation of the present invention in this way, the heat insulating properties of the air conditioning duct can be improved and condensation on the outer periphery of the duct can be prevented. In this case, it is desirable that the nonwoven fabric bonded to the outer periphery of the air conditioning duct be a nonwoven fabric whose effective tensile stress, which is the apparent stress in the MD and TD directions at a tensile elongation value of 5% in the same directions divided by the filling rate in a tensile test, is 25 MPa or less and 1 MPa or more.

[0039] The condensation water drip prevention structure may be for an inorganic building board in which the heat-insulating material for preventing dripping of condensation water is placed on the surface of the inorganic building board with the nonwoven fabric surface as the outer surface, or further in which the resin foam surface of the heat-insulating material for preventing dripping of condensation water placed on the surface of the inorganic building board with the nonwoven fabric surface as the outer surface and the opposing surfaces of the surface of the inorganic building board are bonded to each other and arranged in a horizontal plane, and the inorganic building board is at least one of gypsum board and calcium silicate board.

[0040] The condensation water drip prevention structure may be an inorganic building board that is at least one of gypsum board and calcium silicate board, and the inorganic building board is arranged in a vertical plane direction, with the resin foam surface of the condensation water drip prevention heat insulating material placed on the surface of the inorganic building board with the nonwoven fabric surface as the outer surface, and the opposing surfaces of the resin foam surface of the condensation water drip prevention heat insulating material and the surface of the inorganic building board being bonded to each other.

[0041] In this case, the inorganic building board is arranged in a vertical plane direction, and the nonwoven fabric adhered to the outer surface of the inorganic building board is preferably a nonwoven fabric that satisfies an effective tensile stress of 1 MPa or more and 25 MPa or less, which is the value obtained by dividing the apparent stress in the MD and TD directions at a tensile elongation value of 5% in the same direction by the filling rate in a tensile test.

[0042] The condensation drip prevention structure for a folded-plate roof may be such that the condensation drip prevention heat-insulating material is bonded to the inner surface of a folded-plate roof. By bonding the condensation drip prevention heat-insulating material to the inner surface of the folded-plate roof in this way, it is possible to improve the thermal insulation of the inner surface of the roof and prevent condensation on the inner surface of the roof. In this case, it is desirable that the nonwoven fabric used in the condensation drip prevention structure for a folded-plate roof is a nonwoven fabric whose tensile modulus in both the MD and TD directions satisfies predetermined values, similar to those of air-conditioning ducts.

[0043] The average fiber diameter of the fibers constituting the nonwoven fabric is in the range of 10 to 30 μm, Nonwoven fabric Fiber porosity: 85-98% and a nonwoven fabric with a filling rate of 2 to 15%. Furthermore, the thickness of the nonwoven fabric measured based on JIS L1913 is 1.0 mm or less, and the apparent stress in the MD direction at a tensile elongation value of 5% in the same direction in a tensile test is a filling rate 2~15% Divided by is the effective tensile stress The nonwoven fabric for preventing dripping of condensation may have a compressive strength of 25 MPa or less and 1 MPa or more. In this case, since the above characteristics only define the structural characteristics of the nonwoven fabric, the material of the fibers constituting the nonwoven fabric is irrelevant, and a nonwoven fabric for preventing dripping of condensation can be realized even if the fibers constituting the nonwoven fabric are made of a non-absorbent resin such as polyethylene resin, polypropylene resin, or polyethylene terephthalate resin. Furthermore, in addition to the non-absorbent resin, it is also possible to use water-absorbent resin fibers.

[0044] The water retention capacity of the nonwoven fabric converted to 1 mm of apparent thickness is 500 g / m 2 The nonwoven fabric having the above features may be used as a nonwoven fabric for preventing dripping of condensation water by fusing the nonwoven fabric to the surface of a polyethylene resin foam.

[0045] The fibers constituting the nonwoven fabric may be composed of fibers containing at least one of PET resin, polyethylene resin, polypropylene resin, and acrylic resin, and may further be composed of fibers that do not have a core-sheath structure. The fibers constituting the nonwoven fabric may further contain 30% or less of a total weight of absorbent fibers selected from cellulose fibers, pulp, and rayon fibers. The reason for keeping the content of absorbent fibers below a predetermined value is to prevent a decrease in strength due to an increase in the amount of water absorbed. When using natural fibers such as cellulose fibers and pulp, it is difficult to use long fibers of a predetermined length, so it is preferable to use short fibers.

[0046] moreover The nonwoven fabric At least a part of the fibers is composed of fibers having a core-sheath structure, or the core fibers of the fibers having the core-sheath structure are hollow. Structure The hollow fiber is composed of a fiber having a core. Has a structural core A multi-layered fiber in which a sheath portion is formed around the fiber, and the core-sheath fiber Sheath Or the hollow Structure The nonwoven fabric for preventing dripping of condensation water may be a nonwoven fabric in which the sheath of the fiber forming the core is formed of a resin with a lower melting point than the core, and further, the core fiber of the core-sheath structure is hollow. Structure Fiber and hollow Structure The fiber may have a hollow multi-layer structure in which a sheath is formed around the fiber. By making the core a hollow structure, the flexibility of the nonwoven fabric can be ensured. Protection It becomes possible to do this.

[0047] The nonwoven fabric can also be a nonwoven fabric for preventing condensation water dripping, characterized in that it satisfies both an effective tensile stress of 1 MPa or more and 25 MPa or less, which is the value obtained by dividing the apparent stress in each direction at a tensile elongation value of 5% in the MD and TD directions in a tensile test by the filling rate. By satisfying these characteristics, it is possible to obtain a nonwoven fabric for preventing condensation water dripping that is excellent in both directions or that has condensation water drip prevention performance regardless of the installation direction.

[0048] The fibers constituting the nonwoven fabric may be staple fibers containing at least one of PET resin, polyethylene resin, polypropylene resin, and acrylic resin, and the staple fibers may be fibers that do not have a typical sheath-core structure or fibers at least partially have a sheath-core structure, and if the sheath-core structure is present, the sheath portion may be formed of a resin with a lower melting point than the core portion. The fibers constituting the nonwoven fabric may also contain cellulose fiber, pulp, or rayon fiber at 30% or less of the total fiber weight. The reason for limiting the content of water-absorbent fibers to a predetermined value or less is to prevent a decrease in strength due to an increase in the amount of water supplied.

[0049] In this way, by using non-melting type fibers in which the sheath is made of a resin with a lower melting point than the core, the physical and mechanical properties of the core fiber can be maintained even after fusion by heat-sealing at a lower temperature than the core, which has a higher melting point.Furthermore, by making the core have a hollow structure, the flexibility of the nonwoven fabric can be improved.

[0050] The short fiber nonwoven fabric can be a nonwoven fabric manufactured by a chemical bond method, a thermal bond method, a spunlace method, an airlaid method, a needle punch method, or the like. By using at least a portion of the short fibers manufactured by such a manufacturing method in the nonwoven fabric, condensation can be prevented even when the nonwoven fabric is used in a vertical direction rather than on a horizontal surface. Furthermore, even without using short fibers, a warp-and-warp orthogonal nonwoven fabric or a warp-and-warp oblique nonwoven fabric can also be used as a nonwoven fabric that can reduce the influence of fiber orientation.

[0051] The method for constructing a piping structure in which the condensation-water drip prevention insulation material is wrapped around the outer periphery of a refrigerant pipe, and if the pipe is vertical or diagonal, the method for forming a piping structure may be such that the direction in which the effective tensile stress of the condensation-water drip prevention insulation material satisfies the range of 25 MPa or less and 1 MPa or more is oriented horizontally perpendicular to the direction of the vertical pipe.

[0052] Here, if the piping for preventing dripping of condensation water is vertical or diagonal piping, if the length of the vertical piping is long, it will be affected by gravity, causing competition between evaporation from the surface of the nonwoven fabric and the increase in moisture accumulated within the nonwoven fabric. However, since there is a possibility of condensation water dripping from the bottom of the piping, it is conceivable that by improving the effective tensile stress in the TD direction so as to accelerate evaporation from the surface of the nonwoven fabric by promoting movement to the sides of the nonwoven fabric, it will be possible to promote evaporation from the surface of the nonwoven fabric and prevent dripping of condensation water.

[0053] In a method for forming a structure that prevents condensation water from dripping in an air conditioning duct, the sides of the air conditioning duct are arranged opposite each other in at least the vertical direction, sandwiching the top and bottom surfaces of the duct, and the nonwoven fabric surface is arranged on the side surfaces as the outer surface, facing in a horizontal direction perpendicular to the vertical duct side surfaces, such that the effective tensile stress of the nonwoven fabric of the condensation water drip prevention insulation material is 25 MPa or less and 1 MPa or more.

[0054] In a method for forming a condensation drip prevention structure for an inorganic building material for construction, if the condensation structure of the inorganic building material for construction has a vertical wall structure, the method preferably comprises arranging the nonwoven fabric of the heat-insulating material as an outer surface on the surface of the vertical wall of the inorganic building material, with the direction in which the effective tensile stress of the nonwoven fabric of the condensation drip prevention heat-insulating material satisfies 25 MPa or less and 1 MPa or more, in a horizontal direction perpendicular to the direction of the vertical wall structure. Also, in a method for forming a condensation drip prevention structure for a folded-plate roof, the method preferably comprises arranging the nonwoven fabric of the heat-insulating material as an outer surface on the back surface of the folded-plate roof, with the direction in which the effective tensile stress of the nonwoven fabric of the condensation drip prevention heat-insulating material satisfies 25 MPa or less and 1 MPa or more, in a direction perpendicular to the folding direction of the folded plates of the folded-plate roof. In this case, since the drainage slope when laying a corrugated roof is usually about 3 / 100, this has almost no effect on the dripping of condensation water.

[0055] In the heat-insulating material for preventing dripping of condensation water of the present invention, a nonwoven fabric is fused to at least one surface of a polyethylene-based resin foam, and the average fiber diameter of the fibers constituting the nonwoven fabric is in the range of 10 to 30 μm. Nonwoven fabric A thermal insulation material for preventing dripping of condensation water can be obtained, characterized in that the porosity of the fibers is 85 to 98%, and further, the value obtained by dividing the apparent stress in the MD direction at a tensile elongation value of 5% in the same direction by the filling rate satisfies a value of 25 MPa or less and 1 MPa or more in a tensile test.

[0056] Here, if the above-mentioned heat-retaining material is used, the thickness of the nonwoven fabric measured based on JIS L1913 is 1.0 mm or less, and the water retention capacity converted to 1 mm of apparent thickness of the nonwoven fabric is 500 g / m 2 The above requirements can be satisfied. The condensation water drip prevention performance of the present invention can be obtained regardless of the water absorption of the fibers themselves, so both chemical-based fibers and natural-based fibers can be used as the fibers constituting the nonwoven fabric. Furthermore, the nonwoven fabric of the present invention is characterized by excellent condensation water drip prevention properties as well as excellent embossability, since the porosity and tensile modulus, which are parameters that indirectly reflect the three-dimensional structure of the fibers, as well as the fiber diameter being within a predetermined range. In the heat-insulating material of the present invention, the nonwoven fabric is preferably bonded to the foam by fusion, but may also be bonded by adhesive bonding.

[0057] The mechanism by which the thermal insulation material of the present invention prevents condensation from dripping is believed to be as follows: First, when micro-condensation occurs at the interface between the foam and the nonwoven fabric, the micro-condensation water diffuses in the thickness direction of the nonwoven fabric due to capillary action. The moisture diffused in the thickness direction has a larger contact area with the outside air, making it more likely to be heated by the outside air, which prevents the condensation phenomenon from continuing and the micro-condensation water from becoming larger.

[0058] It is also believed that condensation is suppressed by the diffusion and evaporation of condensed water from the surface of the nonwoven fabric. By setting a predetermined fiber diameter and void ratio, and by setting the value obtained by dividing the stress at 5% tensile elongation by the packing ratio within a predetermined range, it is possible to prevent the dripping of condensed water and obtain a nonwoven fabric that retains a predetermined amount of water. Even if the fiber diameter and void ratio satisfy the predetermined values, if the value obtained by dividing the stress at 5% tensile elongation by the packing ratio does not satisfy the predetermined range, condensation cannot be prevented.

[0059] In addition to the above, when nonwoven fabric is wrapped around a pipe, the nonwoven fabric wrapped around the outer periphery of the insulation material in an approximately cylindrical cross section will have a difference in height in the vertical direction compared to when the nonwoven fabric of the insulation material is used in a flat shape. Therefore, due to the wicking effect caused by capillary action and the downward movement of moisture due to gravity, a gradient according to height occurs in the moisture content contained in the nonwoven fabric above and below the piping structure in which the insulation material is wrapped around the pipe, and the moisture content will be higher at the bottom than at the top of the pipe.

[0060] For example, in the case of horizontal piping, the amount of water on the top surface of the pipe is small, so the contact area with the atmosphere is large, and water evaporates from the top surface of the pipe and is absorbed by capillary action from the bottom side of the pipe to the top side. By maintaining a predetermined relationship between evaporation and absorption, condensation from the pipe can be prevented. Also, in the case of vertical pipes or vertical walls where the insulation covering is uneven between the top and bottom, the effect of gravity is greater than in the case of horizontal piping, so the effect of gravity on the occurrence of condensation must be taken into consideration. However, this problem can be solved if the moisture retained by the nonwoven fabric can be released horizontally by capillary action, increasing the contact area with the air and accelerating the evaporation of condensed water.

[0061] In other words, if the nonwoven fabric of the present invention is constructed so that the direction in which the apparent stress in the same direction at a tensile elongation of 5% divided by the filling rate, which is the predetermined value in a tensile test, satisfies the value of 25 MPa or more and 1 MPa or more, coincides with the horizontal direction when the nonwoven fabric is constructed, or if a nonwoven fabric with improved anisotropy can be used so that the effective tensile stress satisfies the predetermined value whether the nonwoven fabric is constructed so that either the MD direction or the TD direction coincides with the horizontal direction when the nonwoven fabric is constructed, it will be possible to solve the problem of condensation in heat insulating materials and provide a nonwoven fabric that can prevent condensation.Of course, even in this case, it goes without saying that the fiber diameter and porosity of the nonwoven fabric used must satisfy the ranges of the present invention, that is, an average fiber diameter of 10 μm to 30 μm and a porosity of 85 to 95%.

[0062] By coating the periphery of a refrigerant pipe with the heat-insulating material, a piping structure that prevents condensation water dripping can be obtained. By forming an air-conditioning duct in which the heat-insulating material for preventing condensation water dripping is adhered to or coated on the outer surface of the air-conditioning duct, a condensation water drip-preventing air-conditioning duct can be obtained. Furthermore, a structure that prevents condensation water dripping for inorganic building boards can be obtained in which the heat-insulating material for preventing condensation water dripping is disposed on the surface of inorganic building boards. A structure that prevents condensation water dripping for inorganic building boards in which the heat-insulating material for preventing condensation water dripping is disposed on the surface of inorganic building boards and the inorganic building boards are arranged as vertical walls can be obtained. By adhering the material to the inner surface of a folded-plate roof, a condensation water drip-preventing folded-plate roof structure can be obtained. Naturally, the nonwoven fabric itself has excellent water retention and condensation water drip prevention properties. [Effects of the Invention]

[0063] According to the present invention, in a heat insulating material in which nonwoven fabric is arranged on the surface of a polyethylene-based resin foam, the ability to prevent condensation water from dripping can be improved regardless of the material of the nonwoven fabric. [Brief explanation of the drawings]

[0064] [Figure 1]FIG. 1(a) is a diagram showing the test conditions of the condensation test material using a thermo-hygrostat, and FIG. 1(b) is a diagram showing the state of wrapping the condensation water drip prevention heat insulating material around the refrigerant pipe. [Figure 2] Figure 2(a) shows a perspective view of a refrigerant pipe wrapped around its outer periphery in heat insulating material 3 to prevent condensation from dripping, and Figure 2(b) shows a cross-sectional view of Figure 2(a) cut at a predetermined position including the line XX. [Figure 3] Figure 3(a) shows a piping structure in which pipes coated with the heat-insulating material for preventing condensation water dripping of the present invention on the outer periphery of refrigerant pipes are arranged opposite each other and integrated together, and Figure 3(b) shows a cross-sectional view of Figure 3(a) cut at a specified position including the line AA. [Figure 4] FIG. 4 shows a cylindrical refrigerant piping structure in which an existing refrigerant piping is surrounded by the heat insulating material of the present invention. [Figure 5(a)] FIG. 5(a) shows a cylindrical piping structure for hot and cold water supply in which a protective member of the present invention is disposed on the outer periphery of a piping for hot and cold water supply, the outer periphery of which is covered with a resin sheath pipe for protecting the piping. [Figure 5(b)] 5(b)(c) shows a cylindrical piping structure for cold and hot water supply, in which the outer periphery of a resin sheath pipe is covered with a resin foam, and the outer periphery of the resin foam is further covered with the protective member of the present invention. In the figure, (d) is a cross-sectional view taken at a predetermined position including the line BB in the perspective view (c). [Figure 6] FIG. 6 shows a piping structure in which the protective member of the present invention is applied to a vertical piping. [Figure 7] FIG. 7 shows a structure for preventing dripping of condensed water from a duct using the heat insulating material of the present invention. [Figure 8] Figure 8(a) shows a structure for preventing condensation water dripping of inorganic building boards in which a heat-insulating material for preventing condensation water dripping is placed on the surface of the inorganic building boards, and Figure 8(b) shows a structure for preventing condensation water dripping of inorganic building boards in which inorganic building boards in which a heat-insulating material for preventing condensation water dripping is placed on the surface of the inorganic building boards are arranged as vertical walls. [Figure 9] FIG. 9 shows a folded-plate roof structure in which steel plates on the underside of which the nonwoven fabric of the heat-insulating material of the present invention is laminated are folded. [Figure 10(a)]Figure 10(a) is an SEM photograph at 100x magnification of nonwoven fabric 4, which has excellent anti-droplet properties for condensation water. [Figure 10(b)] Figure 10(b) is an optical microscope photograph at 100x magnification of nonwoven fabric 4, which has excellent anti-drip properties for condensation water, after absorbing water. [Figure 10(c)] SEM photograph at 100x magnification of a nonwoven fabric made of diagonal fibers of test material 19. [Figure 10(d)] SEM photograph of a nonwoven fabric using short fibers equivalent to test material 18. DETAILED DESCRIPTION OF THE INVENTION

[0065] Hereinafter, embodiments of the present invention will be described in detail.

[0066] The thermal insulation material for preventing dripping of condensation water of the present invention has a base material that is a polyethylene-based resin foam having closed cells, and a nonwoven fabric is arranged on the surface of at least one side of the polyethylene-based resin foam, and the nonwoven fabric further satisfies a specified configuration, thereby providing a thermal insulation material that satisfies the function of preventing dripping of condensation water.

[0067] The polyethylene foam constituting the base material of the heat-insulating material for preventing dripping of condensation water of the present invention can be produced by a crosslinking and foaming method, such as an extrusion crosslinking and foaming method in which crosslinking is performed by extrusion and foaming is performed after crosslinking.

[0068] (Polyethylene resin foam) As the resin used for the polyethylene foam, polyethylene resin such as LDPE or HDPE can be used alone, or a mixed resin of LDPE and HDPE can be used.

[0069] Furthermore, these polyethylene foams can be imparted with heat resistance or flame retardancy as needed. When a mixed resin of LDPE and HDPE is used, the LDPE and HDPE can be mixed in a predetermined ratio, or the LDPE and HDPE can be mixed in a predetermined ratio, for example, 40 parts by mass of LDPE to 60 parts by mass of HDPE. Furthermore, in the present invention, as will be described later, a heat resistance improver or a flame retardant can be added to the polyethylene foam to make it heat-resistant or flame-retardant. In addition to the above, polyethylene foams containing various additives can be used as long as they do not inhibit foaming or cause resin degradation.

[0070] In addition to LDPE and HDPE, modified polyethylene resins such as EVA (polyethylene copolymer with vinyl acetate) can be used as polyethylene resins. EVA is used instead of polyethylene because it has high flexibility and elasticity, making it suitable for a variety of product applications. For example, F120N manufactured by Ube Maruzen Polyethylene Co., Ltd. can be used for LDPE, HD1300 manufactured by Japan Polyethylene Co., Ltd. can be used for HDPE, and DQDJ-1868 manufactured by ENEOSNUC ​​Co., Ltd. can be used for EVA.

[0071] (crosslinking agents, foaming agents, etc.) Here, the contents of the crosslinking agent and foaming agent used in the polyethylene foam may be, for example, 0.6 to 1.5 parts by weight of crosslinking agent and 10 to 30 parts by weight of foaming agent per 100 parts by mass of polyethylene resin when the expansion ratio is 20 to 40. The above ranges of the crosslinking agent and foaming agent are desirable, but these can be changed as necessary.

[0072] For example, dicumyl peroxide can be used as the crosslinking agent. For example, Percumyl D, a product of Nippon Oil & Fats Corporation, can be used as the dicumyl peroxide crosslinking agent. Furthermore, although inorganic foaming agents may be used as the foaming agent, azodicarbonamide (ADCA), which is an organic decomposition type foaming agent, such as Vinihole AC#LQ, a product of Eiwa Chemical Co., Ltd., can be preferably used.

[0073] Examples of blowing agents that can be used include azodicarbonamide (ADCA), oxybisbenzenesulfonylhydrazide (OBSH), N,N'-dinitrosopentamethylenetetramine (DPT), p-toluenesulfonylhydrazide, benzenesulfonylhydrazide, diazoaminobenzene, N,N'-dimethyl-N,N'-dinitroterephthalamide, and azobisisobutyronitrile, which can be used alone or in combination of two or more. Any of these blowing agents may be used. Typically, azodicarbonamide (ADCA) is often used as the blowing agent.

[0074] In addition to the above, a crosslinking aid and a foaming aid may be added as needed. For example, TMPT (trimethylolpropane trimethacrylate) (trade name: Ogmont) may be added as a crosslinking aid, and zinc oxide may be used as a foaming aid.

[0075] (heat resistance improver, flame retardant) To impart heat resistance, a heat-resistant pigment such as carbon or titanium oxide (rutile type), or both, can be added in a total amount of up to 2.0 parts by mass per 100 parts by mass of resin. Carbon has high conductivity and therefore has a heat dissipation effect, while titanium oxide has excellent heat reflectivity. Furthermore, both carbon and titanium oxide have high heat resistance, which can improve the heat resistance of the resin foam.

[0076] To improve the flame retardancy of the foam, a flame retardant is added, and the flame retardant may be 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, in an amount of 100 parts by mass in total per 100 parts by mass of the resin. In addition to the antimony-based flame retardants, bromine-based flame retardants, and hydroxide-based flame retardants, inorganic fillers may also be added.

[0077] For example, if the content of the flame retardant exceeds 100 parts by mass, the effect saturates and foaming properties are inhibited, so the total amount of flame retardant added is 100 parts by mass or less. If the content of the flame retardant exceeds 100 parts by mass, foaming properties are inhibited by the flame retardant, so the upper limit must be 100 parts by mass or less. Here, the preferred contents of antimony-based flame retardants and bromine-based flame retardants are each 20 parts by mass or less, and the preferred content of hydroxide-based flame retardants is 80 parts by mass or less. Note that since the specific gravity of each flame retardant is higher than that of the resin component, when converted to a volumetric ratio, the mixing ratio relative to the resin component is significantly smaller than the mass ratio, so there are no particular problems as long as the content is within the above range.

[0078] (inorganic filler) Inorganic fillers can be included to the extent that they do not impair the foaming properties, impact resistance, or fire resistance (uniformity of the carbonized layer thickness). Examples of inorganic fillers include calcium silicate, zeolite, talc, mica, silica, alumina, diatomaceous earth, calcium oxide, magnesium oxide, iron oxide, tin oxide, barium carbonate, magnesium carbonate, and montmorillonite. Since a high content of inorganic fillers inhibits foaming properties, it is preferable that at least one of the inorganic fillers be included in an amount of 2 parts by mass or less. Furthermore, the content of these inorganic fillers is preferably 1 part by mass or less.

[0079] (antioxidants, stabilizers) Since antioxidants inhibit foaming of resin foams, it is desirable to use them in small amounts. In addition to antioxidants, light stabilizers, weather resistance agents, etc. may also be included as needed. Adding an antioxidant can prevent oxidative degradation of the base resin that constitutes the foam.

[0080] Antioxidants include phenolic antioxidants, phosphite antioxidants, and blends of phenolic and phosphite antioxidants. Antioxidants that satisfy the above requirements include, for example, hindered phenolic antioxidants and hindered amine compounds. These antioxidants have the effect of not only acting as antioxidants but also as stabilizers or weather resistance agents. For example, in the present invention, Irganox 1010 manufactured by BASF is used as tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane.

[0081] The content of the antioxidant is preferably 0.05 to 1.0 part by mass per 100 parts by mass of the polyethylene resin. If the content of the antioxidant is too high, crosslinking of the base resin is inhibited and the viscosity is reduced, which increases the cell diameter and ultimately causes gas escape, reducing the expansion ratio and resulting in expansion inhibition. Therefore, it is desirable not to add more than 1.0 part by mass of the antioxidant.

[0082] (Other additives) The resin foam of the present invention may further contain other additives such as lubricants, pigments containing carbon or titanium oxide, dyes, plasticizers, fillers, and antistatic agents, depending on the purpose, as long as they do not inhibit foaming. For example, these other additives can be added in an amount of 2 parts by mass or less. For example, adding a predetermined amount of inorganic pigment can impart design features and aesthetic appeal. Known commercially available additives can be used as these additives.

[0083] (Method of manufacturing polyethylene resin foam) 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.

[0084] The resin foam is produced by extruding the foaming base sheet at 120-150°C, followed by continuous expansion to a predetermined expansion ratio in a heating furnace at 200-230°C, and then passing it 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.

[0085] The expansion ratio needs to be controlled taking into consideration heat insulation, embossability, and cushioning properties. 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 heat insulation. Therefore, the expansion ratio of the resin foam is preferably 20 to 40 times, and within this range, there are no particular problems. Regarding cushioning properties, there are no particular problems if the expansion ratio is within the range of 20 to 40 times. In this example, the foam was expanded to 30 times. When expanding to 30 times, 16 parts by mass of an organic decomposable foaming agent and 0.8 parts by mass of a crosslinking agent can be added to 100 parts by mass of the polyethylene resin. In other words, the contents of the foaming agent and crosslinking agent can be appropriately adjusted depending on the expansion ratio.

[0086] In this case, a mixed resin prepared by mixing LDPE and HDPE in a mass ratio of 4:6 may be used as the polyethylene resin. The LDPE used was F120N manufactured by Ube Maruzen Polyethylene Co., Ltd., and the HDPE used was HD1300 manufactured by Japan Polyethylene Co., Ltd. The foaming agent used was Vinihol AC#LQ manufactured by Eiwa Kasei Co., Ltd., and the cross-linking agent used was Perkmyl D manufactured by Nippon Oil & Fats Co., Ltd., in the proportions indicated above.

[0087] In the present invention, the heat-insulating material for preventing dripping of condensation water of the present invention can be obtained by joining a nonwoven fabric to at least one surface of a polyethylene-based resin foam by fusion bonding. Next, the nonwoven fabric to be placed on the polyethylene-based foam will be described. Here, the nonwoven fabric may be joined to the resin foam by adhesion instead of fusion bonding.

[0088] (nonwoven fabric) First, to clarify the definition of nonwoven fabric, the JIS defines it as follows: "Nonwoven fabric is a fabric made by layering fibers without weaving them together and spreading them out into a sheet, such as a fiber sheet, web, or pad, in which the fibers are oriented in one direction or randomly and are bonded by entanglement, and / or fusion, and / or adhesion. However, this does not include paper, woven fabric, tufts, and crepe felt."

[0089] (Fibers used in nonwoven fabrics) The nonwoven fabric of the present invention does not exclude the use of natural fibers such as rayon resins and acetate resins, but primarily prevents condensation by controlling the three-dimensional structure of the nonwoven fabric by adjusting the mechanical properties of the tensile modulus to a predetermined ratio after adjusting the fiber diameter and porosity of the fibers constituting the nonwoven fabric to a predetermined range. Therefore, since the fibers themselves do not need to be water-absorbent, synthetic fibers are used as the fibers constituting the nonwoven fabric. Examples of synthetic fibers that can be used include polyester fibers, polyethylene fibers, polypropylene fibers, and acrylic fibers.

[0090] In the present invention, even if the nonwoven fabric itself is made of fibers that do not have water absorbency, it is possible to impart condensation drip prevention properties to the nonwoven fabric as long as it has a specified structure. The industrial definitions of these fibers are given below in JIS L0204-2 (2001), the JIS for Textile Terminology (Raw Materials Division), Part 2: Chemical Fibers. Note that in the present invention, the three-dimensional structure of the nonwoven fabric is complex and not regular, making it difficult to directly and quantitatively identify the three-dimensional structure of the nonwoven fabric, so tensile modulus is used as an alternative parameter for evaluating it.

[0091] Polyester fibers are fibers made from long-chain synthetic polymers containing 85% or more by mass of ester units of terephthalic acid and dihydric alcohol; polyethylene fibers are fibers made from long-chain synthetic polymers composed of unsubstituted saturated aliphatic hydrocarbons; polypropylene fibers are fibers made from long-chain synthetic polymers composed of saturated aliphatic hydrocarbons with a methyl group side chain on one carbon atom per two carbon atoms, with stereoregularity and no other substituents; and acrylic fibers are fibers made from linear synthetic polymers containing 85% or more by mass of repeating units of acrylonitrile groups.

[0092] Polyester, polyethylene, and polypropylene fibers are non-absorbent, meaning that even if water vapor is adsorbed onto their surfaces, the fibers themselves are not absorbent, resulting in no change in fiber strength and no loss of strength due to water absorption. Acrylic fibers, while slightly weakened by moisture absorption, have a wet-dry strength ratio of 0.9 or higher, a smaller loss in strength than natural fibers such as rayon and vinylon. Therefore, there are no significant problems when acrylic fibers are mixed with other non-absorbent fibers. In addition to polyethylene, polypropylene, polyester, and acrylic fibers, nonwoven fabrics may contain a certain amount of natural fibers such as cellulose, pulp, and rayon. However, the content of these fibers should be kept within 30% of the total fiber weight, taking into account the loss of strength due to moisture absorption. When using cellulose, pulp, or other fibers, short staple fibers are preferred.

[0093] (Nonwoven fiber composition and structure) Here, multiple fibers can be used in the nonwoven fabric used in the present invention. For example, polyethylene fibers can be used in combination with PET fibers, polyethylene fibers, and polypropylene fibers. When polyethylene fibers are used in combination with PET fibers or polypropylene fibers, multiple fibers are mixed in a predetermined ratio, making it easier to control the number of fusion points where the fibers fuse together. This makes it easier to obtain a predetermined three-dimensional structure in the fibers, making it easier to obtain a stable nonwoven fabric even with a high porosity. The advantage of using multiple fibers or fibers with a core-sheath structure is that it is possible to selectively fuse the fibers together by utilizing the difference in melting points of different resins.

[0094] As the nonwoven fabric fibers, 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 advantage of using such fibers with a core-sheath structure in a nonwoven fabric is that when the fibers are to be fused together, for example, by using PET or polypropylene fibers in the core and polyethylene fibers in the sheath, the fibers can be fused together at a relatively low temperature of 120 to 140°C, making it easier to produce the nonwoven fabric. At the same time, by using a fiber with higher strength in the core than in the sheath, the rigidity of the fibers used in the nonwoven fabric can be increased, which allows the fiber diameter of the fibers constituting the nonwoven fabric to be reduced accordingly, making it easier to control the porosity of the nonwoven fabric.

[0095] The nonwoven fabric is constructed using multiple fibers with different melting points, with the low-melting-point fibers melted and used as a binder. Here, when 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. This structure makes it easier to control the porosity and strength of the nonwoven fabric, so that a nonwoven fabric with a predetermined strength can be obtained, even if the porosity is high.

[0096] Here, the nonwoven fabric of the present invention can be made by combining fibers with a core-sheath structure having different melting points with other fibers. For example, by using a fiber with higher strength than the sheath fiber in the core portion, the rigidity of the fibers used in the nonwoven fabric can be increased, and at the same time, the other fibers can be made to be high strength or hollow. Structure By using fibers or the like 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.

[0097] Furthermore, when long fibers are used as the fibers for the nonwoven fabric of the present invention, the fibers tend to be oriented in the MD direction, which is the main direction during the production of the nonwoven fabric, and as a result, the mechanical properties in that direction tend to be higher in rigidity than the mechanical properties in the TD direction.However, by using short fibers, the influence of fiber orientation in the MD direction can be alleviated, making it possible to improve the orientation in the TD direction, and an improvement in anisotropy can be expected.It is also estimated that the same effects as those of short fibers can be obtained by using a warp-and-warp orthogonal nonwoven fabric or a warp-and-warp oblique nonwoven fabric.

[0098] Furthermore, a nonwoven fabric that can reduce the influence of fiber orientation in the MD and TD directions without using short fibers is a warp-to-warp cross nonwoven fabric. A warp-to-warp cross nonwoven fabric is a nonwoven fabric in which warp webs and weft webs are laminated and bonded perpendicularly. A warp-to-warp cross nonwoven fabric is a nonwoven fabric in which warp webs and weft webs are cross-laminated using a laminator, and then these warp webs are longitudinally stretched, while the weft webs are transversely stretched. In addition to the above, there is a weft-to-warp oblique nonwoven fabric in which a nonwoven fabric intersecting the weft-to-warp cross nonwoven fabric with an oblique nonwoven fabric added. By using a weft-to-warp cross nonwoven fabric or a weft-to-warp oblique nonwoven fabric, the influence of fiber orientation can be reduced, even in a nonwoven fabric that uses long fibers without short fibers, thereby achieving the same effects as a nonwoven fabric using short fibers.

[0099] By using a nonwoven fabric that satisfies the structural characteristics of the heat insulating material for preventing condensation water dripping of the present invention, such as fiber diameter, void ratio (filling rate), and the presence or absence of bent portions in the fibers, the condensation water drip prevention properties are not affected, and there is no need to use a water-absorbent resin.The thickness of the nonwoven fabric can be 1.0 mm or more, but even if the thickness of the nonwoven fabric is 1.0 mm or less, the condensation water drip prevention properties and the embossing processability described below can be satisfied.

[0100] (Nonwoven fabric manufacturing method) Next, we will look at how nonwoven fabrics are manufactured. Nonwoven fabrics are usually made by forming a thin, membrane-like sheet called a web, which is made up of only fibers, and then bonding the fibers that make up the formed web together as needed.

[0101] There are various methods for forming nonwoven fabrics. For example, there are both wet and dry methods for forming webs. In the wet method, fibers are made into nonwoven fabric in a manner similar to that used in the papermaking process. In the dry method, there are various methods for forming webs, as described below, and either method may be used to form a web. However, when using long fibers for the purpose of preventing dripping of condensation water in the present invention, it is necessary to bend the fibers to form the three-dimensional structure of the nonwoven fabric, so it is desirable that the fibers of the nonwoven fabric have the ability to bend.

[0102] To obtain a nonwoven fabric from a web, the fibers that make up the web must be bonded at predetermined positions. There are various methods for bonding the fibers in a web, including chemical bonding methods such as dipping and spraying, thermal bonding, spunbonding, meltblowing, meltplaining, airlaying, spunlace (water exchange method), and needlepunching. Methods for forming nonwoven fabrics using long fibers include the chemical bonding, thermal bonding, spunbonding, meltblowing, and meltplaining methods described below. Methods for forming nonwoven fabrics using short fibers include the chemical bonding, thermal bonding, airlaying, spunlace, and needlepunching methods. Note that the chemical bonding, thermal bonding, airlaying, and spunlace methods can be used for both long and short fibers.

[0103] 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.

[0104] The air-laying method uses air and a binder to bond pulp to form nonwoven fabric. The spunlace method uses high-pressure water jets to entangle fibers. The needle-punch method is a method of manufacturing 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.

[0105] In particular, in the present invention, the nonwoven fabric only needs to have structural characteristics such as a predetermined fiber diameter and a predetermined porosity, and so there are no restrictions on the manufacturing method of the nonwoven fabric as long as a nonwoven fabric that satisfies these structural characteristics can be obtained. Any method may be used to manufacture the nonwoven fabric as long as it has the predetermined fiber diameter range used in this application, the predetermined porosity, and the crimping properties of the fibers of the nonwoven fabric so that the effective stress value at 5% elongation in a tensile test satisfies the predetermined value, and the nonwoven fabric can be used for the purpose of the present invention.

[0106] When the nonwoven fabric used in the present invention is manufactured using short fibers, the chemical bonding method, thermal bonding method, air-laying method, spunlace method, or needle punching method is often used. When using a nonwoven fabric using such short fibers, it is expected that the difference in fiber orientation between the MD and TD directions can be reduced compared to when using a nonwoven fabric using long fibers. Therefore, there is a possibility that the difference in the mechanical properties of the nonwoven fabric can also be reduced.

[0107] Furthermore, a nonwoven fabric that can reduce the influence of fiber orientation in the MD and TD directions without using short fibers is a warp-to-warp cross nonwoven fabric. A warp-to-warp cross nonwoven fabric is a nonwoven fabric in which warp webs and weft webs are laminated and bonded perpendicularly. A warp-to-warp cross nonwoven fabric is a nonwoven fabric in which warp webs and weft webs are cross-laminated using a laminator, and then these warp webs are longitudinally stretched, while the weft webs are transversely stretched. In addition to the above, there is a weft-to-warp oblique nonwoven fabric in which a nonwoven fabric intersecting the weft-to-warp cross nonwoven fabric with an oblique nonwoven fabric added. By using a weft-to-warp cross nonwoven fabric or a weft-to-warp oblique nonwoven fabric, the influence of fiber orientation can be reduced, even in a nonwoven fabric that uses long fibers without short fibers, thereby achieving the same effects as a nonwoven fabric using short fibers.

[0108] (Method of bonding nonwoven fabric to polyethylene resin foam) The nonwoven fabric and the polyethylene-based resin foam can be fused together by placing a nonwoven fabric on one surface of the polyethylene-based 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.

[0109] (Embossing method) For example, embossing can be performed by heating a material in which a nonwoven fabric is fused to one surface of a foam body to a predetermined temperature using an infrared heater and passing it through a pair of upper and lower embossing rolls.

[0110] When embossing, the surface of the material passing through the embossing roll is heated to a predetermined temperature, for example, 120 to 150° C., with an infrared heater, and the embossing roll itself is cooled to maintain the roll surface temperature at a predetermined temperature, for example, 20° C., taking into consideration adhesion of the material passing through the roll, such as a nonwoven fabric, to the roll surface. By heating the material and cooling the roll in this manner, it is possible to prevent the nonwoven fabric attached to the surface from being burned.

[0111] The uneven pattern used in the embossing process is not particularly limited and may have any shape as long as it can be formed. In the present invention, however, the bottom surface is approximately 4.0 mm. 2 ×Top surface 2.5mm 2 An embossing process is performed to form a square pyramidal truncated pattern with a length of approximately 1.2 mm and a height of approximately 1.2 mm across the entire width of the product, with each side of the square pyramidal truncated pattern coinciding with the MD and TD directions, respectively.

[0112] During the embossing process, the nonwoven fabric itself is heated and molded, and although deformation strain has an effect on the three-dimensional structure, the effect is not significant, and differences in structural characteristics between test materials are maintained. However, compared to non-embossed materials, the embossing process has an adverse effect on preventing condensation, so the condensation evaluation test after embossing is a relatively severe test compared to the untreated case. If the embossed product does not drip condensation during the condensation evaluation test, then the untreated product will not drip condensation due to condensation. [Example]

[0113] (Measurement method) In the following examples, since the thermal insulation material of the present invention is composed of a resin foam and a nonwoven fabric, various thermal insulation materials with different compositions and structures, and different foam compositions, were used to evaluate the embossability of these thermal insulation materials before and after embossing by a condensation evaluation test to determine whether or not condensation water dripped. Here, since the structure of the nonwoven fabric is thought to have a large effect on condensation resistance and embossability, the parameters that determine the structure of the nonwoven fabric were determined as follows: fiber diameter, filling rate, porosity, and the effective stress value at 5% elongation in a tensile test, and water retention was evaluated. In addition, as necessary, the structure of the nonwoven fabric fibers was observed using an SEM, and the nonwoven fabric after water absorption was observed under an optical microscope.

[0114] (Method for measuring and evaluating nonwoven fabrics) As measurement and evaluation methods for evaluating the structure of nonwoven fabrics, we will explain how to measure fiber diameter, nonwoven fabric thickness, porosity, and filling rate, how to measure effective tensile stress values ​​through tensile tests, and how to observe nonwoven fabrics using SEM and optical microscopes.As a performance evaluation method related to the condensation properties of nonwoven fabrics, we will explain how to measure water retention capacity.In addition to the performance evaluation tests for nonwoven fabrics, we will also explain how to evaluate the condensation properties and embossability of thermal insulation materials.

[0115] (Nonwoven fabric thickness) The thickness of the nonwoven fabrics used in the test ranged from 0.22 mm to 0.95 mm. The thickness of the nonwoven fabrics used in the test was measured in accordance with the JIS method using a nonwoven fabric thickness measuring device (φ56.4 mm disc flat probe) capable of measuring in the same way as Method A of the JIS general nonwoven fabric measurement method (JISL1913:2010).

[0116] (fiber diameter) The fiber diameter of the nonwoven fabric was determined by randomly selecting 20 locations from the SEM fiber image and calculating the average fiber diameter (number average) using image processing software. The average fiber diameter of the nonwoven fabric used in the present invention was in the range of 10 μm to 30 μm, and fibers in this range are usually used for nonwoven fabrics. While it is possible to manufacture a nonwoven fabric with a fiber diameter of 10 μm or less, the strength of the nonwoven fabric is insufficient at fiber diameters of 10 μm or less, resulting in reduced durability of the protective member surface during use. Furthermore, if the fiber diameter exceeds 30 μm, the increase in the diameter of the nonwoven fabric relatively increases the filling rate of the nonwoven fabric, making it difficult to maintain the porosity in the range of 85 to 98%. Therefore, it is desirable to set the average fiber diameter in the range of 10 to 30 μm. For the test materials in each example of the embodiment, the measured fiber diameter of each test material is listed as the fiber diameter for simplicity, but these measured fiber diameters refer to the average fiber diameter.

[0117] (porosity, filling rate) The porosity of the nonwoven fabric was calculated by calculating the apparent specific gravity from the thickness and basis weight of the nonwoven fabric, and using the apparent specific gravity, the true specific gravity used to calculate the porosity etc. is determined by the underwater displacement method. Here, the unit of porosity is volume %. Porosity (%) = {1 - (apparent specific gravity / true specific gravity)} x 100 Filling rate (%)=100-Porosity rate (%)

[0118] (Measurement of effective tensile stress value in tensile test) It is difficult to evaluate the crimping property, which indicates the degree of entanglement or bending of the fibers in a nonwoven fabric, or the effect of fiber junctions, for each individual fiber and convert it into a macro parameter for the entire nonwoven fabric structure. Therefore, by evaluating parameters related to the elongation value and stress in tensile tests for each nonwoven fabric as alternative parameters for evaluating the three-dimensional structure of the nonwoven fabric fibers, we measured and evaluated the effective tensile stress value at 5% elongation, which is the value obtained by dividing the stress value at 5% elongation in a tensile test by the filling rate, i.e., the value normalized by the filling rate, as an evaluation parameter associated with the porosity to ensure water retention.

[0119] The behavior of elongation and stress change in the tensile test in this test affects not only water retention but also embossability, and it is considered desirable for both to have a large elongation value in the tensile test and a small increase in stress in the low strain region, so these behaviors were confirmed through tensile tests. Furthermore, when taking into account the winding strain around the refrigerant pipe, in the case of the TD direction, since the winding strain around the refrigerant pipe is added in addition to the strain from the embossing, it is considered desirable for the elongation value in the TD direction to be larger than the elongation value in the MD direction and for the stress increase in the tensile test to be small.

[0120] Here, the effective stress values ​​were measured only in the MD direction because the TD direction is perpendicular to the web direction of the nonwoven fabric. This means fewer bonding points and entanglements between fibers per given length, making it difficult to measure strain stably with a strain gauge. Furthermore, we found that the stress rise time for all nonwoven fabrics was slower than in the MD direction. Therefore, it was difficult to determine the effective stress value at 5% elongation in the TD direction. Since we determined that the evaluation parameters for the tensile behavior in the MD direction would affect the nonwoven fabric's water retention and condensation drip prevention properties, we prioritized determining the effective stress value at 5% elongation in the MD direction. As described below, in Example 3 of the first embodiment, we created short-fiber nonwoven fabrics and warp-and-warp oblique nonwoven fabrics with improved effective tensile stress in the TD direction. Therefore, for some materials, the effective tensile stress in the TD direction was also determined in addition to the effective tensile stress in the MD direction.

[0121] The effective stress value of the nonwoven fabric was determined to be the effective stress value at 5% elongation because, based on preliminary test results, the stress value at 2% elongation would measure a small deformation range, making it difficult to guarantee accuracy due to variations in the uniformity of the nonwoven material and the precision of the strain measurement, and the small effective tensile stress level would make it difficult to identify differences between materials. On the other hand, at 10% elongation, deformation could be applied to a stress level range where effects caused by differences in the three-dimensional structure of the fibers within the nonwoven fabric, as well as macrostructural changes due to changes in the state of engagement, friction, and fusion between the fibers of each nonwoven fabric, and secondary changes in the state of the nonwoven fabric as tensile deformation progresses, may be apparent, making it impossible to accurately evaluate the three-dimensional structure of the nonwoven fabric in its initial state. Therefore, the effective stress value at 5% elongation was considered appropriate as a parameter indirectly representing the structure of the nonwoven fabric.

[0122] From each nonwoven fabric, a JIS K6251 (2017) No. 1 dumbbell-shaped test piece was punched out in the MD direction, the sample was held with a chuck distance of 80 mm, the gauge length was 40 mm, and a tensile test was performed at 10 mm / min. The effective tensile stress was measured when the strain between the gauge lines reached 5%, and this value was divided by the fiber filling rate of the nonwoven fabric to express the normalized effective stress value at 5% elongation as the effective tensile stress value at 5% elongation. Note that, to take into account the variation in effective tensile stress values, three tests were performed, and the average value was defined as the effective tensile stress value for each material.

[0123] (SEM and optical microscope observation of nonwoven fabric) To confirm the degree of bending and entanglement structure of the fibers that make up the nonwoven fabric, representative examples of nonwoven fabrics that were effective in preventing condensation water dripping and nonwoven fabrics that were not effective in preventing condensation water dripping were observed using a scanning electron microscope (SEM) at an accelerating voltage of 20 kV and a magnification of 100x.In addition, to confirm the water retention state of nonwoven fabrics that were effective in preventing condensation water dripping, optical microscope observations were conducted using the same materials as those used for SEM observations at a magnification of 100x, the same as for SEM observations, while the nonwoven fabrics were in a water-retained state.

[0124] The water absorption procedure for the test piece, in which the water retention state of the nonwoven fabric was confirmed using an optical microscope, was carried out as follows: First, a 30 mm x 30 mm piece of nonwoven fabric was cut out and immersed in a beaker of water for at least 2 minutes to allow it to absorb sufficient water. After that, the sample was lifted with tweezers, and after waiting for all the water droplets to drip off, the sample was placed in contact with the edge of the beaker and held there for 30 seconds. This was then placed on the sample stage of the microscope and measured using the optical microscope.

[0125] (Water retention capacity) A certain area of ​​nonwoven fabric is cut out from each nonwoven fabric used in the test and weighed. Then, this nonwoven fabric is immersed in tap water and allowed to absorb enough water. After that, it is lifted for 30 seconds or more, and once no water droplets have fallen, it is weighed again. The water-retained weight is divided by the area to obtain the unit area (m 2 ) is calculated as the water retention capacity (g / m 2 ) Note that, since the nonwoven fabrics used in the test were of different thicknesses, the water retention capacity of each nonwoven fabric was compared by converting it into the water retention capacity for a given nonwoven fabric thickness of 1 mm. The water retention capacity on the left side of Tables 1 to 3 is the measured water retention capacity, and the water retention capacity on the right side shows the converted water retention capacity g / (m.mm) for a nonwoven fabric thickness of 1 mm.

[0126] (Condensation drip prevention evaluation test) FIG. 1 shows the condensation test using a thermo-humidistat chamber. For the condensation test, four condensation-preventing insulation materials, each consisting of a resin foam with a nonwoven fabric fused to its surface, were wrapped around a stainless steel pipe as a refrigerant pipe, with the outer surface facing outward, and the pipe was placed in a thermo-humidistat chamber 1. For the test, stainless steel pipes 2 (outer diameter 49φ × inner diameter 45φ × wall thickness 2mm) were used as refrigerant pipes. Various insulation materials 3 were prepared, each consisting of a 10mm-thick foam with a 30x expansion ratio and a nonwoven fabric fused to one surface. These insulation materials were cut to 150mm lengths and wrapped around the entire circumference of the refrigerant pipe 2. For each test material, the insulation materials 3 were both embossed, with the nonwoven fabric surface embossed, and unembossed, with no embossing. Hereinafter, the thermo-humidistat chamber may be referred to simply as a thermostatic chamber.

[0127] For the test, after the above preparations were completed, the thermostatic chamber was maintained at 23°C and 50% RH for three hours. After that, a 5°C refrigerant was passed through the stainless steel pipe 2, and the temperature was raised to a test temperature of 35°C and 90% RH over 30 minutes. After that, the thermal insulation material for preventing condensation was maintained for 12 hours, and the presence or absence of condensation was evaluated by placing a drop sensor 5 directly below each test piece to check whether water droplets condensed and dripped. During the test, the temperature outside the refrigerant pipe was checked at point A, the surface temperature of the nonwoven fabric at point B, and the ambient temperature inside the thermostatic chamber at point C. The measured temperatures at points A, B, and C were controlled to within ±0.5°C of the set temperature.

[0128] The temperature inside the thermostatic chamber was confirmed by temperature measurement using thermocouples positioned as shown in the figure. The thermocouples were used to measure three things: the ambient temperature inside the thermostatic chamber, the surface temperature of the embossed nonwoven fabric, and the interface temperature between the stainless steel pipe and the polyethylene resin foam. The thermocouples were set so that the error in the measured temperatures at the same measurement positions was within ±0.5°C. Four test specimens were placed in the thermostatic chamber, and the test to confirm the presence or absence of condensation water dripping was repeated for each test specimen in Examples 1 to 3 described below, depending on the number of test specimens. Therefore, trays for measuring the presence or absence of condensation water dripping were positioned corresponding to the position of each test specimen. When there were fewer than four test specimens, specimens not being measured were placed in the thermostatic chamber to ensure consistent test conditions. Test results were evaluated as "Good" for specimens with no condensation water dripping and "Poor" for specimens with condensation water dripping.

[0129] FIG. 1(b) is a cross-sectional view of the heat insulating material 3 surrounding the refrigerant pipe 2 in a condensation evaluation test when embossing has been performed. The heat insulating material 3 wrapped around the outer periphery of the refrigerant pipe 2 is made of a resin foam 7 and a nonwoven fabric 8, with the nonwoven fabric 8 placed on the outermost surface of the resin foam 7, and the nonwoven fabric 6 being embossed to form irregularities at the embossed portion 9. The thickness of the nonwoven fabrics used in the test differed depending on the nonwoven fabric, as shown in Table 1. 1(b) is a cross-sectional view showing a laminated structure in which a resin foam is placed around the stainless steel pipe used as a refrigerant pipe during testing, and a nonwoven fabric is placed on the outermost periphery. The surface of the nonwoven fabric is embossed to form irregularities.

[0130] (Embossability) A polyethylene resin foam material with nonwoven fabric fused to one surface is heated to a predetermined temperature by an infrared heater and passed through a pair of upper and lower embossing rolls to form a sheet with a thickness of approximately 4.0 mm on the bottom. 2 ×Top surface 2.5mm 2Embossing processability was evaluated by embossing a square pyramidal pattern measuring approximately 1.2 mm in length and 1.2 mm in height across the entire width of the product, with each side of the pattern aligned with the MD and TD directions.

[0131] Specifically, embossability was evaluated by evaluating 10 pieces each in the MD and TD directions. The evaluation was based on whether the target shape was consistently achieved, with a rating of ◯ if the target shape was achieved in the embossed area evaluated, and × if at least one piece had a crushed surface or the target shape was not achieved, or if the fibers forming the nonwoven fabric were damaged.

[0132] As a first embodiment of the present invention, Tables 1 to 3 show the results of an evaluation test of the condensation water drip prevention properties of various thermal insulation materials and the results of evaluation of embossability. As a second embodiment, the results of applying the thermal insulation material of the present invention to various piping structures are shown. As a third embodiment, the results of applying the thermal insulation material of the present invention to building materials are shown. Examples of application to architectural structures are described in order: a condensation water drip prevention structure for inorganic building materials, a condensation water drip prevention structure for ducts, and a condensation water drip prevention structure for folded-plate roofs. Here, the ducts refer to air conditioning ducts. However, because ducts are relatively large components formed in architectural structures, in this invention, the condensation water drip prevention structure for ducts is included in the embodiments of application to architectural structures. Furthermore, for each fiber constituting the nonwoven fabric of the test material in Examples 1 to 3 (Tables 1 to 3) of the first embodiment, fibers with a core-sheath structure are shown in parentheses, with the left side of the parentheses representing the core and the right side representing the sheath. Usually, the fibers constituting the sheath have a lower melting point than the fibers constituting the core.

[0133] (First embodiment: Example 1) For all test materials, LDPE foam was used as the resin foam, expanded to a thickness of 10 mm at a 30x expansion ratio. Nonwoven fabrics 1 to 5, each with a different fiber structure, were fused onto the LDPE foam to obtain the thermal insulation materials (Test Materials 1 to 5). The nonwoven fabrics were fused to the foam surface using hot roll molding under the conditions described above. Various tests were conducted to determine the nonwoven fabric structure, as well as condensation evaluation tests and embossability tests for the thermal insulation materials. The effects of the nonwoven fabric structure on condensation and embossability were evaluated. For reference, Table 1 lists the sources of the nonwoven fabrics used in the tests.

[0134] In addition to test materials 1 to 5, a conventional insulation material that generates condensation was also tested, which was made by fusing a polyethylene film to the surface of a polyethylene resin foam. The conventional material has a film thickness of 80 μm, and therefore has no voids, so it can be said to be a material with a filling rate of 100% and a void rate of 0%, and this was designated conventional material 1.

[0135] Here, test material 1 is PET fiber with a fiber diameter of 17.3 μm, a filling rate of 16.2%, a porosity of 83.8%, and little fiber bending; test material 2 is PET fiber with a fiber diameter of 17.1 μm, a porosity of 97.8%, and much fiber bending; test material 3 is (PP / PE) / PET fiber with a fiber diameter of 19.4 μm, a porosity of 95.4%, and much fiber bending; test material 4 is acrylic / (PET / PE) fiber with a fiber diameter of 11.7 μm, a porosity of 91.2%, and much fiber bending; and test material 5 is PET / PE fiber with a fiber diameter of 18.9 μm, a porosity of 97.6%, and much fiber bending. Here, the nonwoven fabric 1 of test material 1 had a void ratio of not more than 85% and little bending, whereas the non-shrunk fabrics 2 to 5 of test materials 2 to 5 had fiber diameters in the range of 10 to 30 μm, void ratios in the range of 85 to 98%, and relatively many bent fiber sections were observed.

[0136] Here, test materials 1 and 2 are nonwoven fabrics made of ordinary PET fiber alone, test material 3 is specifically a nonwoven fabric made of a composite fiber of PP / PE fiber with a core-sheath structure (a fiber with a core-sheath structure in which PP is the core material and the outside is covered with PE) and PET fiber, and test material 4 is a nonwoven fabric made of acrylic fiber and a fiber with a core-sheath structure in which PET fiber is covered with PE fiber, just like test material 3. Test material 5 is a nonwoven fabric made of a blend of PE fiber and PET fiber.

[0137] (Test results) Table 1 shows the test results for Example 1 of the first embodiment. According to the test results in Table 1, in the test to evaluate the ability to prevent condensation water dripping after embossing, the thermal insulation materials of Test Materials 2 to 5 showed good results, with no dripping of condensation water, whereas Test Material 1 and the conventional material dripped condensation water. Regarding the relationship between the presence or absence of condensation water dripping in the test materials and the structure of the nonwoven fabric, it was confirmed that condensation water dripping did not occur in nonwoven fabrics with an average fiber diameter in the range of 10 to 30 μm, a porosity of 85 to 98% (filling ratio of 2 to 15%), and an effective tensile stress of 25 MPa or less, which is the apparent tensile stress in the MD direction at a tensile elongation value of 5% divided by the filling ratio in a tensile test. Specifically, the effective tensile stress values ​​of Test Materials 2 to 5 were in the range of 7.2 to 17.2 MPa. The results of SEM observation, which will be described later, confirmed that these nonwoven fabrics that do not drip condensation have many bent fiber sections and high fiber crimping. Furthermore, the water retention capacity of nonwoven fabrics that do not cause condensation is 500 g / m2, calculated per 1 mm of apparent thickness of the nonwoven fabric. 2 The results of the condensation water drop test before embossing were the same as those before embossing, and the embossing did not have any effect on the condensation water drop.

[0138] In contrast, Test Material 1, the nonwoven fabric on which condensation occurred, had a fiber diameter that satisfied the above-mentioned range of 10 to 30 μm, but had a porosity of less than 85% and a filling rate of more than 15%, meaning that the porosity was low, and the effective tensile stress, which is the apparent stress in the MD direction at a tensile elongation of 5% in the same direction divided by the filling rate in a tensile test, was 38.5 MPa, far exceeding 25 MPa. Furthermore, there were few bends in the fibers that made up the nonwoven fabric, and the nonwoven fabric had low crimpability. The water retention capacity at which a nonwoven fabric cannot prevent dripping is 500 g / m2, calculated per 1 mm of apparent thickness of the nonwoven fabric. 2 did not satisfy the above. As described above, it was confirmed that nonwoven fabrics with a high porosity and a small effective tensile stress value at a specified strain of 5% elongation are superior in terms of the occurrence of condensation. Furthermore, although the fibers used in the test were chemical fiber-based materials with no water absorption, it was considered that the ability of the nonwoven fabric of the present invention to prevent condensation from dripping is basically achieved solely by the structure, regardless of the type of fiber.

[0139] Based on the results of test materials 1 to 5, it was found that in the case of test materials 4 and 5, which are thermal insulation materials using fibers with a core-sheath structure, the water retention and anti-dripping properties of condensation water are correlated with the void ratio of the fiber and the effective tensile stress calculated by dividing the tensile stress at 5% elongation by the filling rate, regardless of whether the fibers forming the nonwoven fabric are made of a single fiber, fibers with a core-sheath structure, or composite fibers made of two different materials.

[0140] The reason for these results is that when a nonwoven fabric with a high porosity is cooled below the dew point, the fibers have a lot of bending and are crimped, so when cooled to a temperature below the dew point, many independent water films form in the three-dimensional spatial network created by the fibers of the high-porosity nonwoven fabric, connecting the fibers, and a large amount of water is retained in the nonwoven fabric. Conversely, when the nonwoven fabric has a low porosity and a high filling rate, the high filling rate reduces the space in which water films can form. The formation of water films is based on facts confirmed using an optical microscope.

[0141] Regarding embossability, test material 1, which had a high filling rate, had a lot of overlapping fibers, which caused the nonwoven fibers to break and the shape of the embossed area to become unstable due to the elastic recovery of the fibers, resulting in poor embossability. Test materials 2 to 5, on the other hand, had an average fiber diameter of 10 to 30 μm and a high porosity of 85 to 98%, so there was no deterioration in embossability, such as fiber breakage or unstable shape due to fiber interactions caused by overlapping fibers.

[0142] As a result, if the nonwoven fabric has an average fiber diameter of 10 to 30 μm and a high porosity of 85 to 98%, and the nonwoven fabric is 1.0 mm or less in thickness, and the effective tensile stress, which is the apparent tensile stress in the MD direction at a tensile elongation value of 5% in the tensile test divided by the filling rate, is 1 MPa or more and 25 MPa or less, the water retention of the insulation material for preventing condensation water dripping can be ensured regardless of whether it is embossed or not.

[0143] [Table 1]

[0144] (First embodiment: Example 2) Although the composition of the foamed resin was thought to have little effect on the condensation-preventing properties, in Example 2, experiments were conducted to confirm the effect of the composition of the polyethylene-based resin foam on condensation resistance and embossability using the resin compositions and nonwoven fabric combinations shown in Table 2. In Example 2, the polyethylene-based resin foam composition was changed from LDPE to various polyethylene-based foams such as HDPE, a mixed resin of LDPE and HDPE, or EVA resin. If necessary, resin foams were prepared by adding carbon or titanium oxide to improve heat resistance or flame retardants to improve flame retardancy. Nonwoven fabric 2 or nonwoven fabric 4, which have excellent condensation-preventing properties, were fused to these resin foams to prepare thermal insulation materials (Test Materials 6 to 13). As in Example 1, the foams used for these thermal insulation materials all had an expansion ratio of 30 times and a foam thickness of 10 mm. The amounts of the blowing agent and crosslinker were adjusted appropriately within the above-mentioned ranges.

[0145] The insulation material for test material 6 was HDPE resin foam, while test material 7 was a 6:4 mixed resin of LDPE and HDPE. Test materials 8 to 11 were foams made from the LDPE and HDPE mixed resin with various additives. Specifically, test material 8 was made from the mixed resin with 0.5 parts by mass of carbon added, test material 9 was made from 2.0 parts by mass of titanium oxide added, test material 10 was made from 1.0 part by mass of antimony trioxide and 4.0 parts by mass of a brominated flame retardant added, and test material 11 was made from a resin foam with 20 parts by mass of magnesium hydroxide added. Test material 12 was made from EVA with 80 parts by mass of magnesium hydroxide added, and test material 13 was made from EVA with 50 parts by mass of aluminum hydroxide added. Here, the heat insulating material for test materials 6 to 11 was a nonwoven fabric 2 using PET fiber, and for test materials 12 and 13, a nonwoven fabric 4 using acrylic / (PET / PE) fiber was used.

[0146] (Test results) Table 2 shows the test results for Example 2. The test results in Table 2 indicate that the foam composition of the thermal insulation materials 6 to 13 did not affect the condensation drip prevention test in a thermostatic chamber, and no condensation dripping occurred. Furthermore, the embossability was also good. Therefore, for all of the thermal insulation materials in Example 2, if the nonwoven fabric fused to the surface of the polyethylene resin foam satisfies the specified fiber diameter of 10 to 30 μm and the specified porosity of 85 to 98%, as confirmed in Example 1, and the stress normalized by the filling rate at 5% elongation is 25 MPa or less, it is believed that the condensation drip prevention properties will be satisfactory regardless of the foam resin composition. Furthermore, the thickness of the nonwoven fabric used in these thermal insulation materials was 1 mm or less, and the water retention capacity per mm of nonwoven fabric thickness was 500 g / (m.mm), and these thermal insulation materials also had no problems with embossability, as in Example 1.

[0147] [Table 2]

[0148] (First embodiment: Example 3) Table 3 shows the results of a test conducted to identify and search for materials that not only meet the effective tensile stress (MD tensile elongation at 5% elongation, calculated by dividing the apparent stress in the MD direction by the packing fraction) of 25 MPa or less and 1 MPa or more, but also meet the effective tensile stress (TD tensile elongation at 5% elongation, calculated by dividing the apparent stress in the TD direction by the packing fraction) of 25 MPa or less and 1 MPa or more, regardless of the direction of the tensile test. The purpose of this test was to confirm the difference in the condensation drip prevention properties of condensation drip prevention insulation materials by meeting the required effective tensile stress (apparent stress divided by the packing fraction) of 25 MPa or less and 1 MPa or more, regardless of the direction of the tensile test. For reference, Table 3 also lists the source of the nonwoven fabric used in the test.

[0149] Table 3 shows the test results for test materials 14 to 19. Test materials 14 to 16 are nonwoven fabrics made of long fibers oriented in the MD direction, test materials 17 and 18 are nonwoven fabrics made of short fibers, and test material 19 is a nonwoven fabric made of warp-to-warp oblique long fibers. Test material 14 is a nonwoven fabric made of acrylic / (PET / PE) fibers with a fiber diameter of 11.7 μm, a porosity of 91.2%, and a high degree of fiber curvature. Test material 15 is a nonwoven fabric made of PET / PE fibers with a fiber diameter of 18.9 μm, a porosity of 97.6%, and a high degree of fiber curvature.

[0150] (Test results) Test material 14 is a nonwoven fabric made of acrylic fiber and a core-sheath fiber in which the outer periphery of a hollow PET fiber is covered with PE fiber. Test material 15 is a nonwoven fabric made of a blend of PE fiber and PET fiber. Here, the non-shrunk fabrics of test materials 14 and 15 have fiber diameters in the range of 10 to 30 μm, a void ratio in the range of 85 to 98%, and a relatively large number of bent fiber portions.

[0151] Test material 14 is a nonwoven fabric made of long fibers of PET / PE fiber and acrylic fiber, and is the same material as test material 4 in Table 1, which is a nonwoven fabric with a core-sheath structure in which PET forms the core and PE forms the sheath. Test material 14 differs from test material 4 in that the test value of effective tensile stress in the TD direction was added in addition to the case of test material 4. In the tensile test of test material 14, the effective tensile stress, which is the value obtained by dividing the apparent stress in the MD and TD directions at 5% tensile elongation by the filling rate, was 11.5 and 0.91 MPa, respectively, and the fiber diameter was 11.7 μm and Nonwoven fabric Since the fiber porosity is 91.2%, the fiber diameter, porosity, and effective tensile stress in the MD direction all satisfy the range of 25 MPa to 1 MPa at a tensile elongation of 5%, but the effective tensile stress in the TD direction at a tensile elongation of 5% does not satisfy the above range. In this case, the water retention capacity per mm of the nonwoven fabric is 700 g / m 2 There was no dripping of condensed water before or after embossing, and the embossing process was also good.

[0152] Test material 15 is a nonwoven fabric made of long fibers with a core-sheath structure of PET and PE fibers, and is the same material as test material 5 in Table 1. Test material 15 differs from test material 5 in that the test value of the effective tensile stress in the TD direction was added. In the tensile test of test material 15, the effective tensile stress, which is the value obtained by dividing the apparent stress in the MD and TD directions at 5% tensile elongation by the filling rate, was 17.2 and 0.97 MPa, respectively. The fiber diameter was 18.9 μm, Nonwoven fabric Since the fiber porosity is 97.6%, the fiber diameter and porosity are within the ranges of the present invention, and the effective tensile stress is also within the range of the present invention, that is, 25 MPa or less and 1 MPa or more when the tensile elongation in the MD direction is 5%, but the effective tensile stress in the TD direction at a tensile elongation of 5% does not satisfy the above range. In this case, the water retention capacity per mm of the nonwoven fabric is 1383 g / m 2 There was no dripping of condensed water before or after embossing, and the embossing process was also good.

[0153] The test material 16 is a nonwoven fabric made of long fibers with a core-sheath structure of PET / PE fibers. In a tensile test of this test material 16, the effective tensile stresses, which are the values ​​obtained by dividing the apparent stress in the MD and TD directions at 5% tensile elongation by the filling ratio, were 15.30 and 2.10 MPa, respectively. The fiber diameter was 17.0 μm, Nonwoven fabric Since the porosity of the fiber is 95.6%, the average fiber diameter, porosity, and effective tensile stress are all within the range of the present invention, that is, 10 to 30 μm, Nonwoven fabric The porosity of the fiber is 85-98%, and the effective tensile stress in the same direction at a tensile elongation of 5% is 25 MPa or less and 1 MPa or more in both the MD and TD directions. In this case, the water retention capacity per 1 m of nonwoven fabric is 1303 g / m 2 There was no dripping of condensed water before or after embossing, and the embossing process was also good.

[0154] Test material 17 is a nonwoven fabric made of short fibers with a core-sheath structure of PET / PE fibers. In a tensile test of this test material 17, the effective tensile stresses, which are the values ​​obtained by dividing the apparent stress in the MD and TD directions at 5% tensile elongation by the filling rate, were 16.6 and 12.9 MPa, respectively. Nonwoven fabric Since the porosity of the fiber is 97.2%, the average fiber diameter is 10 to 30 μm, which is within the range of the present invention, for the fiber diameter, porosity, and effective tensile stress. Nonwoven fabric The porosity of the fiber is 85-98%, and the effective tensile stress in the same direction at a tensile elongation of 5% is 25 MPa or less and 1 MPa or more in both the MD and TD directions. In this case, the water retention capacity per 1 m of nonwoven fabric is 937 g / m 2 There was no dripping of condensed water before or after embossing, and the embossing process was also good.

[0155] The test material 18 is a nonwoven fabric made of short fibers of composite fibers of PET / PE fiber and pulp. In a tensile test of this test material 18, the effective tensile stress, which is the apparent stress in the MD direction and the TD direction at 5% tensile elongation divided by the filling rate, was 3.50 and 3.30 MPa, respectively. The fiber diameter was 18.3 μm, Nonwoven fabricSince the porosity of the fiber is 91.1%, the average fiber diameter is 10 to 30 μm, which is within the range of the present invention, for the fiber diameter, porosity, and effective tensile stress. Nonwoven fabric The porosity of the fiber is 85-98%, and the effective tensile stress in the same direction at a tensile elongation of 5% is 25 MPa or less and 1 MPa or more in both the MD and TD directions. In this case, the water retention capacity per 1 m of nonwoven fabric is 1247 g / m 2 There was no dripping of condensed water before or after embossing, and the embossing process was also good.

[0156] Test material 19 is a nonwoven fabric made of long fibers having an oblique structure of PET / PE fibers. In a tensile test of this test material 19, the effective tensile stress, which is the apparent stress in the MD direction and the TD direction at 5% tensile elongation divided by the packing ratio, was 8.89 and 4.41 MPa, respectively. The fiber diameter was 18.0 μm and the fiber porosity was 94.4%. Therefore, the fiber diameter, porosity, and effective tensile stress were all within the ranges of the present invention, with an average fiber diameter of 10 to 30 μm and Nonwoven fabric The porosity of the fiber is 85-98%, and the effective tensile stress in the same direction at a tensile elongation of 5% is 25 MPa or less and 1 MPa or more in both the MD and TD directions. In this case, the water retention capacity per 1 m of nonwoven fabric is 925 g / m 2 There was no dripping of condensed water before or after embossing, and the embossing process was also good.

[0157] Here, the ratios of the effective tensile stress in the TD direction to the effective tensile stress in the MD direction, which is the apparent stress at 5% tensile elongation divided by the filling rate, for test materials 14 and 15 are 0.08 and 0.06, respectively, which show high anisotropy and the effective tensile stress in the TD direction of these materials is less than 1 MPa, whereas the ratios of the effective tensile stress in the TD direction to the effective tensile stress in the MD direction for test materials 16 to 19 are 0.14 to 0.94, which shows little difference in the effective tensile stress in the TD and MD directions and all of them exceed 2 MPa.

[0158] The vertical and diagonal structures in Table 3 indicate whether condensation dripping occurs when the insulation material of the present invention is applied to vertical and diagonal pipes and structures. When test materials 14 and 15 are used, the effective tensile stress in the TD direction is less than 1 MPa. Therefore, when the insulation material is installed with the normal MD direction aligned with the vertical direction, condensation dripping occurs. Therefore, the evaluation result for condensation prevention in vertical and diagonal structures is "×." On the other hand, when test materials 16-19 are used, the effective tensile stress in both the MD and TD directions exceeds 1 MPa. Therefore, even when the insulation material of the present invention is used in vertical and diagonal pipes and structures, condensation dripping does not occur. Therefore, the evaluation result for condensation prevention in vertical and diagonal structures is "○." Furthermore, even when the insulation materials of test materials 14 and 15 are installed with the MD direction aligned with the horizontal direction rather than vertical, they achieve the same effect as materials with effective tensile stresses in the MD and TD directions exceeding 1 MPa, and therefore condensation dripping does not occur.

[0159] As described above, a nonwoven fabric having an average fiber diameter of 10 to 30 μm, a high porosity of 85 to 98%, a thickness of 1.0 mm or less, and an effective tensile stress in the MD direction in a tensile test that satisfies a range of 25 MPa or less and 1 MPa or more, while also satisfying similar tensile properties in the TD direction, can be obtained not only when short fibers are used in the nonwoven fabric, but also when long fibers are used in the nonwoven fabric, by using long fibers with an oblique structure, and it was confirmed that a thermal insulation material for preventing condensation water dripping can be obtained using such a nonwoven fabric.

[0160] [Table 3]

[0161] (Second embodiment: Application of the heat insulating material of the present invention to refrigerant piping and hot and cold water supply piping structure) Next, as a second embodiment, various piping structures to which the thermal insulation material of the present invention is applied will be described. The following five types of piping structures will be described: a piping structure in which the thermal insulation material of the present invention is wrapped around the outer periphery of a piping, a glasses-type piping structure in which two pipes with thermal insulation material wrapped around the outer periphery of the piping are opposed to each other and the opposed parts are thermally fused together, a cylindrical piping structure in which existing refrigerant piping is surrounded by the thermal insulation material of the present invention, a cylindrical piping structure in which existing cold and hot water supply piping and its protective pipe are surrounded by the thermal insulation material of the present invention, and a piping structure in which the protective member of the present invention is applied to vertical piping.

[0162] (Second embodiment: Example 1) (Piping structure in which the heat insulating material of the present invention is wrapped around the outer periphery of a refrigerant pipe) FIG. 2(a) shows a perspective view of a piping structure in which a heat-insulating material 3 for preventing condensation water drips is wrapped around and covered around the outer periphery of a refrigerant pipe 2. The pipe in FIG. 2(a) is a piping in which the heat-insulating material 3, which is made by fusing an embossed nonwoven fabric 8 and a polyethylene-based resin foam 7, is wrapped around the outer periphery of a refrigerant pipe of a heat exchanger, with the embossed portion 9 of the nonwoven fabric facing the outer periphery and the resin foam surface in contact with the pipe. The heat-insulating materials 3 wrapped around the outer periphery of the refrigerant pipe 2 face each other at heat-sealed portions 11, and the opposing surfaces are fixed by heat fusion or adhesive. FIG. 2(b) shows a cross-sectional view taken at a predetermined position including a line XX that intersects the pipe shown in FIG. 2(a) at a right angle. A refrigerant at a predetermined temperature flows through the refrigerant pipe 2. The embossed portion 9 is arranged so that it faces the outer periphery of the heat insulating material 3 in order to facilitate deformation of the outer periphery in response to the difference in circumferential length between the inner and outer peripheries of the nonwoven fabric covering the refrigerant pipe 2.

[0163] (Second embodiment: Example 2) (Spectacle-shaped piping structure in which refrigerant pipes coated with the heat-insulating material of the present invention are integrated and faced each other) FIG. 3(a) shows a pair of glasses-shaped piping structures 10 in which refrigerant pipes 2, each covered with a heat-insulating material 3 for preventing dripping of condensation, are arranged facing each other and integrated together. In piping structures 10a and 10b, the heat-insulating materials 3 wrapped around the outer periphery of the refrigerant pipes 2 face each other at heat-sealed portions 11, and the opposing surfaces are fixed by heat fusion or adhesive. FIG. 3(b) shows a cross-sectional view of the piping structure cut at a predetermined position including a line AA that intersects the two pipes shown in FIG. 3(a) at a right angle, with a refrigerant at a predetermined temperature flowing inside the refrigerant pipes 2. The reason for arranging the embossed portion 9 so that it faces the outer periphery of the heat-insulating material 3 is to facilitate deformation of the outer periphery of the nonwoven fabric covering the refrigerant pipes 2.

[0164] The heat insulating material of the present invention is wrapped around the outer circumference of the refrigerant pipes of a heat exchanger to form two tubular pipes. At least one of the pipes is heated and melted near the surface of the nonwoven fabric, which is the skin part of the heat insulating material, to a predetermined temperature above the melting point of the nonwoven fabric using hot air, a heating plate, ultrasound, a laser, etc., and immediately afterwards, the part is heat-sealed or heat-pressed to obtain a tubular pipe structure with a pair of eyeglass-shaped cross sections.

[0165] 3(a), the pipe shown in Fig. 2(a) can be formed by placing both ends of the heat insulating material of the pipe wrapped with the heat insulating material opposite each other, pressing the opposing surfaces together, and heat fusing them at a predetermined temperature to obtain a glasses-shaped pipe structure in which the heat insulating material, in which the nonwoven fabric is attached to the surface of the resin foam by heat fusing, is wrapped around the outer periphery of the pipe. In this case, the both ends of the heat insulating material wrapped around the pipe can be fixed by heat fusing as described above, or by bonding with double-sided tape or the like.

[0166] Here, the pipe with the smaller diameter of the eyeglass-shaped piping is the liquid refrigerant pipe, and the pipe with the larger diameter is the gas refrigerant pipe. In this way, a piping structure can be obtained in which the heat-insulating material of the present invention is wrapped around the outer periphery of the refrigerant pipe of a heat exchanger so that the embossed surface of the nonwoven fabric is located on the outer surface. By obtaining such a piping structure, it is possible to prevent dripping of condensation water, which occurs in conventional eyeglass-shaped piping structures in which a heat-insulating material made of a polyethylene-based resin foam with a resin film such as polyethylene attached to the surface of the piping is wrapped around the piping.

[0167] (Second embodiment: Example 3) (Cylindrical piping structure in which existing refrigerant piping is surrounded by the heat insulating material of the present invention) 4 shows a cylindrical refrigerant piping structure 16 in which multiple refrigerant pipes, drain pipes, and wiring are surrounded by the thermal insulation material of the present invention. This piping structure will now be described. A typical example of this piping is a set of refrigerant pipes 2 (two pipes), drain pipe 12, and wiring 13 for an air conditioner, as the piping of a general heat exchanger. The refrigerant pipes 2, drain pipe 12, and wiring 13 of the heat exchanger are combined, and these pipes and wiring are entirely surrounded by a cylindrical thermal insulation material 14 with the nonwoven fabric 25-forming surface facing the outer periphery, so that the heat exchanger's indoor and outdoor units can be connected. In this case, both ends of the thermal insulation material 3 surrounding the combined pipes and wiring can be fixed by heat fusion or by adhesive bonding with double-sided tape or the like.

[0168] Here, in the case of conventional piping, the piping structure is such that a resin foam sheet with a resin film attached to the surface of each individual pipe as a thermal insulation material covers the outer periphery of the pipe. However, unlike the present invention, which uses a nonwoven fabric that satisfies a specified fiber diameter, filling rate, and tensile modulus as a mechanical property, fused to the surface of the resin foam, this thermal insulation material does not have the effect of preventing condensation water from dripping. Therefore, although the foam has a thermal insulation effect, even when it is used to cover the outer periphery of the pipes of multiple existing heat exchangers, or a set of pipes consisting of a drain pipe and wiring, it is not possible to prevent condensation water from dripping from the thermal insulation material.

[0169] The entire cross section of this set of piping and wiring can be surrounded by the sheet-like heat-insulating material of the present invention with the nonwoven fabric surface facing outward to form a cylindrical piping structure. In this case, by cylindrically surrounding the outer periphery of this set of piping and wiring, including the drain pipe, with the heat-insulating material of the present invention with the nonwoven fabric facing outward, it is possible to prevent condensation from occurring on the outer periphery of the piping.

[0170] (Second embodiment: Example 4) (Cylindrical piping structure in which existing water and hot water supply piping and its protective pipe are surrounded by the heat insulating material of the present invention) Furthermore, the piping structure cylindrically surrounded by the heat-insulating material of the present invention is not limited to the refrigerant piping for a heat exchanger as described above. As shown in Fig. 5(a), a tubular piping structure 19a for hot and cold water supply can be formed in which the protective member of the present invention is disposed on the outer periphery of a resin sheath pipe 17, which is a protective pipe for the outer periphery of a cross-linked polyethylene pipe 15 serving as a piping for hot and cold water supply. As with the tubular piping structure for a heat exchanger described above, both ends of the tubular heat-insulating material 14 wrapped around the piping can be fixed by heat fusion or by bonding with double-sided tape or the like.

[0171] Here, in the case of a conventional existing water and hot water supply piping, a piping structure is used in which a corrugated resin sleeve pipe 17 serving as a protective pipe is covered around the outer periphery of a cross-linked polyethylene pipe 15 serving as the water and hot water supply piping, but the outer periphery of the water and hot water supply piping is not covered with a foam sheet 18. Therefore, when only the resin sleeve pipe 17 is covered as a protective pipe, condensation may occur on the outer surface of the sleeve pipe 17 exposed as the outermost layer depending on the usage environment. By cylindrically surrounding the outer periphery of the resin sleeve pipe with the heat-insulating material of the present invention, it is possible to prevent condensation from occurring on the outer periphery of each piping and the outer periphery of wiring, and it is possible to prevent condensed water from dripping from the outer periphery of the cylindrical piping structure.

[0172] By using the thermal insulation material of the present invention to form a cylindrical piping structure in which the outer periphery of a resin sheath pipe serving as a protective pipe for hot and cold water supply piping is cylindrically surrounded by the protective member of the present invention, it is possible to prevent the dripping of condensation water that is expected when the hot and cold water supply piping is used in a harsh environment with only the sheath pipe covered.

[0173] Furthermore, as shown in Fig. 5(b), a cylindrical piping structure 19b may be used in which the outer periphery of a resin sheath pipe protecting the cross-linked polyethylene pipe of Fig. 5(a) is covered with a cylindrical heat insulating material 14 coated with a resin foam. The outer periphery of a resin sheath pipe protecting a cross-linked polyethylene pipe as a cold water / hot water supply piping shown in Fig. 5(b) may be covered with a resin foam 7, and the outer periphery of this resin foam 7 may be further covered with a cylindrical protective member 14 of the present invention to form a cylindrical piping structure. By using such a structure, condensation occurring on the outer periphery of the cold water / hot water supply piping can be more reliably prevented.

[0174] (Second embodiment: Example 5) (Piping structure in which the protective member of the present invention is applied to vertical piping and its forming method) In the case of a pipe covered with the heat insulating material of the present invention so that the MD direction is aligned with the horizontal direction, no dripping of condensation water is observed, but in the case of a vertical pipe covered with the heat insulating material so that the MD direction is aligned with the vertical direction, a situation in which the suction effect due to surface tension and the settling and dripping of condensation water due to gravity compete with each other is considered. An experiment was conducted to confirm the presence or absence of problems such as the presence or absence of condensation when the pipe of the present invention is used as a vertical pipe.

[0175] Figure 6 shows a piping structure in which the protective member of the present invention is applied to a vertical pipe. Figure 6 shows a roughly U-shaped piping structure in which vertical pipes are installed symmetrically on both sides of a horizontal pipe inside a thermo-hygrostat. This piping structure has a 25 cm left vertical pipe 20 that descends vertically to the left of the center of the horizontal pipe, and a 25 cm right vertical pipe 21 that ascends vertically to the right of the horizontal pipe via a horizontal pipe 22 of about 30 cm.

[0176] Figure 6 shows the piping structure including the vertical pipes in this case, in which a confirmation experiment was conducted to confirm the occurrence of condensation water by using piping with insulation wrapped around the left and right vertical pipes 20, 21, placing the entire piping in a thermostatic chamber at a temperature of 35°C and humidity of 90%, and circulating a refrigerant at a temperature of 5°C through the piping. Here, the weight of condensation water in each pipe was measured by placing a tray 23 at the bottom of the vertical pipe, and measuring the change in weight of the tray before and after the test in which condensation water 24 was collected on the tray 23.

[0177] Thermal insulation material X is a thermal insulation material using a nonwoven fabric whose effective tensile stress in the MD direction only satisfies the range of 25 MPa to 1 MPa in a tensile test. Thermal insulation material Y is a thermal insulation material for preventing condensation dripping whose effective tensile stress in both the MD and TD directions satisfies the range of 25 MPa to 1 MPa.

[0178] As a result, for the vertical pipe in which insulation material X was wrapped so that its MD direction coincided with the vertical direction, dripping began one hour after being placed in the thermostatic chamber, and 40.9 g of dripping water had dripped in 15 hours, whereas for the vertical pipe in which insulation material Y was wrapped so that its MD direction coincided with the vertical direction, no condensation water dripped even 15 hours after being placed in the thermostatic chamber. Here, insulation material X is an insulation material equivalent to test material 14 in Table 3, and insulation material Y is an insulation material that satisfies test material 17 in Table 3.

[0179] Furthermore, when the insulation materials of test materials 17, 18, and 19 in Table 3 were wrapped around a vertical pipe in the same way, no condensation water dripped. The reason for this is thought to be that in the case of insulation materials 16 to 19, the effective tensile stress in both the MD and TD directions was 25 MPa or less and 1 MPa or more, so the moisture retained by the nonwoven fabric moved horizontally in the TD direction and evaporated, preventing condensation water from forming. For this reason, a vertical pipe structure that prevents condensation water dripping can be obtained by covering a vertical pipe with an insulation material that has an effective tensile stress in both the MD and TD directions of 25 MPa or less and 1 MPa or more.

[0180] Furthermore, in a vertical piping configuration in which a condensation-preventing thermal insulation material is wrapped around the periphery of a refrigerant pipe, the piping can be formed in such a way that at least one direction in which the condensation-preventing thermal insulation material has an effective tensile stress of 25 MPa or less and 1 MPa or greater is oriented horizontally, perpendicular to the vertical piping direction. In this way, by covering the piping with a thermal insulation material having an effective tensile stress of 25 MPa or less and 1 MPa or greater, in a horizontal direction, the same effect as using a thermal insulation material having an effective tensile stress in the TD direction of 25 MPa or less and 1 MPa or greater can be achieved, preventing condensation from dripping, even without using a thermal insulation material having an effective tensile stress in the TD direction of 25 MPa or less and 1 MPa or greater. This is thought to be due to the effect of condensation water adsorbed or retained in the nonwoven fabric evaporating easily from the surface of the nonwoven fabric.

[0181] (Third embodiment: Application of the heat insulating material of the present invention to a structure for preventing condensation water from dripping from a building component) As examples of application of the heat-insulating material of the third embodiment of the present invention to building components, Examples 1 to 3 show a structure for preventing dripping of condensation water from a duct, a structure for preventing dripping of condensation water from inorganic building materials, and a structure for preventing dripping of condensation water from a folded-plate roof.

[0182] (Third embodiment: Example 1) (Duct condensation drip prevention structure and its formation method) FIG. 7 shows a condensation drip prevention structure 30 for a duct body 29 using a thermal insulation material 3 of the present invention. A rectangular parallelepiped duct measuring 25 cm thick, 30 cm long, and 30 cm high was created. The surface of the foam 7 on the back surface of the thermal insulation material was adhesively bonded to the duct body 29 so that the nonwoven fabric-forming surface of the thermal insulation material was positioned on the surface of the duct body 29. This resulted in a structure in which the nonwoven fabric-forming surface 8 on the outer surface of the thermal insulation material 3 and the entire surface of the duct body 29 were covered with the nonwoven fabric 8 of the thermal insulation material. This structure was placed in a thermo-hygrostat, and a condensation drip prevention test was conducted by flowing refrigerant gas through the duct under the same conditions as in the condensation drip prevention piping structure for a vertical piping of Example 5 of the second embodiment. Results similar to those obtained in the vertical refrigerant piping were obtained.

[0183] The results of this test showed that the dripping behavior of condensation water on the duct surface differed depending on the type of insulation covering the duct's exterior surface. For example, when using insulation materials with an effective tensile stress of 25 MPa or less and 1 MPa or more in both the MD and TD directions, such as test materials 16 to 19, no dripping of condensation water from the duct's outer periphery was confirmed. Furthermore, when insulation materials with an effective tensile stress of 25 MPa or less and 1 MPa or more in the MD direction only and an effective tensile stress of 1 MPa or less in the TD direction only, such as test materials 14 and 15, were placed on the side of the duct with the MD direction facing upward, dripping of condensation water was observed. When the insulation materials of test materials 14 and 15 were placed on the side of the duct with the TD direction facing horizontally, no dripping of condensation water was observed. In order to prevent condensation water from dripping from such a duct, a method of forming the duct structure can be used in which at least one direction in which the effective tensile stress of the condensation water drip prevention insulation material satisfies the range of 25 MPa or less and 1 MPa or more is oriented in a horizontal direction perpendicular to the direction parallel to the vertical direction of the duct side wall.

[0184] (Third embodiment: Example 2) (Prevention of condensation dripping from inorganic building boards and method for forming same) FIG. 8(a) shows a horizontal condensation drip prevention structure 27 for inorganic building boards, in which a condensation drip prevention heat-insulating material is placed on the surface of inorganic building board 26. In this case, the condensation drip prevention structure for inorganic building boards may also be formed by further bonding the opposing surfaces of condensation drip prevention heat-insulating material 3 and inorganic building board 26 together. In this invention, at least one of gypsum board and calcium silicate board can be used as inorganic building board 26. In this case, the usage state corresponds to the heat-insulating material portion on the duct top surface in Example 1 of the third embodiment. Therefore, the nonwoven fabric used in horizontal condensation drip prevention structure 27 for inorganic building boards placed on the surface of inorganic building board 26 does not need to consider the downward movement of condensation due to gravity. Therefore, any nonwoven fabric may be used, as long as its effective tensile stress in the MD direction at 5% elongation in a tensile test is 25 MPa or less and 1 MPa or more. This structure makes it possible to prevent condensation on the surface of gypsum boards and calcium silicate boards when they are arranged horizontally.

[0185] Figure 8(b) shows a vertical condensation drip prevention structure 28 for inorganic building boards, in which inorganic building boards 26 with condensation drip prevention heat-insulating material 3 bonded to their surfaces are arranged vertically as vertical walls. In this case, as can be seen from the experimental results for the duct in Figure 7, the nonwoven fabric heat-insulating material that can be used in vertical wall structures does not satisfy the effective tensile stress of 25 MPa or less and 1 MPa or more at 5% elongation in the MD direction in horizontal wall structures, but rather a vertical wall structure must be formed with a heat-insulating material arranged on the surface that satisfies the effective tensile stress of 25 MPa or less and 1 MPa or more at 5% elongation in the MD and TD directions of the nonwoven fabric used for the heat-insulating material.

[0186] In this case, the effective tensile stress values, which are the mechanical properties in both directions of the nonwoven fabric of the thermal insulation material used for vertical wall construction, must satisfy the above-mentioned constraints. This is because condensation drips from the bottom of the thermal insulation material placed vertically on the surface of the inorganic building board. Therefore, the nonwoven fabric structure must have a predetermined effective tensile stress in the TD direction to prevent condensation dripping, thereby accelerating transpiration from the surface of the nonwoven fabric by promoting the movement of condensation to the sides of the nonwoven fabric. In addition, to form a vertical condensation drip prevention structure 28 for inorganic building boards 26 placed vertically as vertical walls, similar to the case of ducts, it is also possible to use a method in which at least one direction in which the effective tensile stress of the condensation drip prevention material satisfies the range of 1 MPa to 25 MPa is aligned horizontally, perpendicular to the direction parallel to the vertical direction of the inorganic building board.

[0187] (Third embodiment: Example 3 - Structure for preventing condensation water dripping from a folded plate roof and its forming method) Figure 9 shows a condensation drip prevention structure 32 for a folded-plate roof, which is made by laminating steel plates, with the nonwoven fabric 8 of the thermal insulation material 3 of the present invention on the underside of the steel plates of a folded-plate roof 31, and folding the steel plates. The folded-plate roof 31 usually has a predetermined width on the top and bottom sides, and is formed into a roughly V-shaped repeating shape with oblique sides that sandwich the top and bottom sides. For example, one cycle can be formed to a roof height of 160 to 180 mm and a width of approximately 500 mm.

[0188] For example, in a condensation test simulating use on a folded-plate roof, a structure was used in which a 0.8 mm thick galvanized steel plate (registered trademark) was used, and an insulating material made of polyethylene resin foam and nonwoven fabric that meets specified mechanical properties was attached to the surface, thereby realizing a structure that prevents condensation water from dripping from the folded-plate roof.

[0189] Similarly, when using the condensation drip prevention structure of the folded-plate roof shown in Figure 9, taking into account the difference in vertical height of the folded-plate roof's folding structure, it is necessary to use insulation material with an effective tensile stress of 1 MPa or more and 25 MPa or less in both the MD and TD directions.When test materials 16 to 19 in Table 3 were used as actual roofing materials, it was confirmed that there was no dripping of condensation from the nonwoven fabric on the surface of the insulation material at the bottom of the folded-plate roof.

[0190] Furthermore, when insulation materials with an effective tensile stress in the MD direction only (such as test materials 14 and 15) satisfying the range of 25 MPa to 1 MPa but an effective tensile stress in the TD direction of less than 1 MPa were used, condensation was observed dripping from the surface of the insulation material on the lower slope of the folded-plate roof. Even with these insulation materials, condensation can be prevented from dripping from the nonwoven fabric on the surface of the insulation material by attaching the MD direction to the back of the folded-plate roof in a direction perpendicular to the folding direction of the folded plates of the folded-plate roof. Therefore, to achieve a condensation drip prevention structure for a folded-plate roof, at least one direction in which the condensation drip prevention insulation material's effective tensile stress satisfies the range of 25 MPa to 1 MPa must be oriented perpendicular to the folding direction of the folded-plate roof, and a formation method that satisfies this requirement is required.

[0191] Figure 10(a) shows the results of SEM observation at 100x magnification of nonwoven fabric 4, a representative example of a material that did not drip condensation in the condensation confirmation test and is a representative example of a nonwoven fabric with excellent condensation drip resistance. It can be seen that nonwoven fabric 4 has many bends and a highly crimped structure. Although no specific photograph is shown, it was found that nonwoven fabric 1, used in test material 1, which did drip condensation, had relatively few bends and low crimp. Figure 10(b) shows the results of optical microscopy observation at 100x magnification of nonwoven fabric 4 with excellent condensation drip resistance after water absorption. This photograph reveals that a water film forms connecting the three-dimensional structure of the bends in the fibers of the nonwoven fabric, resulting in the nonwoven fabric retaining condensation. Figure 10(c) shows a 100x SEM image of a nonwoven fabric made of diagonal fibers (Test Material 19). This image shows a stronger horizontal (TD) flow in the field of view compared to Figure 10(a). Figure 10(d) shows a nonwoven fabric made of short fibers (Test Material 18). Similarly, the horizontal (TD) flow in the field of view is improved compared to Figure 10(a). This promotes the migration of moisture retained on the fiber surfaces and in the intertwined fiber regions toward the TD, even when the insulation is used in a structure with a high vertical component, as in normal applications, by aligning the MD direction with the vertical direction. This promotes the evaporation of retained moisture within the nonwoven fabric, suppressing the aggregation of condensed water on the lower fibers, and thus preventing the dripping of condensed water. Here, the pulp fibers in the field of view appear to have a fiber diameter of about 40 μm, but because the pulp fibers have been crushed and beaten, the fiber thickness is 10 μm or less, and the average fiber diameter of the pulp taking into account the aspect ratio (average of the dimensions of the pulp in the width and thickness directions) is 30 μm or less, which generally satisfies the fiber diameter range specified in this application.

[0192] As described above, in the present invention, by making the nonwoven fabric fused to the surface of the thermal insulation material have a predetermined structure, it has been confirmed that it is possible to obtain a thermal insulation material for preventing condensation water dripping, a piping structure for preventing condensation water dripping, a folded-plate roof structure for preventing condensation water dripping, and a nonwoven fabric for use in a thermal insulation material for preventing condensation water dripping. Furthermore, looking at the results of SEM photograph observation of Example 4, which has excellent condensation water drip prevention properties, it can be seen that a water film is formed connecting the three-dimensional structure of the fibers of the nonwoven fabric, and as a result, the nonwoven fabric retains condensation water.

[0193] Furthermore, in this invention, the application of the heat insulating material to vertical piping or structures for preventing condensation water from dripping from building components has been described as an invention of a method for forming these structures when these structures are formed vertically, but it is also possible to make this invention a method for using the heat insulating material in structures for preventing condensation water from dripping from these vertical piping or building components.

[0194] In addition to the above, other tests were conducted, such as a water absorption rate measurement test in which 2.5 μml (one drop) of tap water is dropped onto nonwoven fabric and the time it takes for the water to soak in is measured; a water absorption length measurement test in which a piece of nonwoven fabric of a specified size is cut out and the last 2 mm is immersed in water for 30 seconds and the length that runs up the nonwoven fabric is measured to measure the length of absorption; and a test in which a strip of nonwoven fabric of a specified size is used on a plastic (acrylic plate) surface inclined at a 23.5° angle to determine the water propagation speed (cm / min / 0.3 mL) over a period of 60 seconds, but none of the tests showed any correlation with condensation properties.

[0195] Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical scope of the present invention is not limited to the above-described embodiments. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the technical ideas described in the claims, and it is understood that these modifications and alterations also fall within the technical scope of the present invention. [Explanation of symbols]

[0196] 1. Constant temperature bath 2. Refrigerant pipes (stainless steel pipes, copper pipes) 3. Heat insulation material 4. Temperature measurement point 5. Droplet sensor 6. Refrigerant 7. Resin foam 8. Nonwoven fabrics 9. Embossed area 10.Glasses type piping structure 10a, 10b Piping structure 11. Heat-sealed part 12.Drain pipe 13. Wiring 14.Cylindrical insulation material 15. Cross-linked polyethylene pipe 16.Cylindrical piping structure for refrigerant 17.Resin sheath tube 18. Foam 19a, 19b: Tubular piping structure for water and hot water supply 20. Left side vertical piping 21. Right side vertical piping 22.Horizontal piping 23. Trey 24. Condensation water 25.Heat insulation material surface (non-woven fabric) 26.Inorganic architectural board materials 27. Structure for preventing horizontal condensation dripping from inorganic building boards 28. Structure for preventing vertical condensation dripping on inorganic building boards 29. Metal duct 30. Duct condensation drip prevention structure 31. Metal folded plate 32. Structure to prevent condensation from dripping from metal folded plates

Claims

1. A heat insulating material for preventing dripping of condensation water, in which a nonwoven fabric is placed on the surface of a polyethylene resin foam, wherein the substrate is a sheet-like polyethylene resin foam having closed cells, and the nonwoven fabric is fused or adhered to one surface of the substrate, the thickness of the nonwoven fabric measured in accordance with JIS L1913 is 1.0 mm or less, the average fiber diameter of the fibers constituting the nonwoven fabric is in the range of 10 to 30 μm, the porosity of the fibers of the nonwoven fabric is 85 to 98%, and the filling rate is 2 to 15%, and further the nonwoven fabric satisfies an effective tensile stress of 1 MPa or more and 25 MPa or less, which is the value obtained by dividing the apparent stress in the MD direction at a tensile elongation value of 5% in the MD direction in a tensile test by the filling rate of 2 to 15%, Furthermore, the water retention capacity of the nonwoven fabric converted into an apparent thickness of 1 mm is 500 g / m ２ A heat insulating material for preventing dripping of condensation water, which is disposed on the outer surface of a pipe, a heat exchanger or a building component, characterized by the above.

2. 2. The dew condensation water drip prevention heat insulating material according to claim 1, characterized in that the ratio of effective tensile stress in the MD direction to that in the TD direction is 0.14 to 0.

94.

3. The heat insulating material for preventing dripping of condensation water as described in claim 1, characterized in that the fibers constituting the nonwoven fabric of the heat insulating material are composed of fibers containing at least one of PET resin, polyethylene resin, polypropylene resin, and acrylic resin.

4. 4. The heat insulating material for preventing dripping of condensation water according to claim 3, wherein the fibers constituting the nonwoven fabric of the heat insulating material further contain cellulose fibers, pulp fibers, or rayon fibers in an amount of 30% or less of the total fiber weight.

5. The heat insulating material for preventing dripping of condensation water as described in claim 3 or claim 4, characterized in that at least a portion of the fibers constituting the nonwoven fabric of the heat insulating material are composed of fibers having a core-sheath structure, or further, the core fibers of the fibers having the core-sheath structure are composed of fibers having a core with a hollow structure, and the core fibers are multi-layered fibers in which a sheath portion is formed around the hollow fibers having the core with a hollow structure, and the sheath portion of the core-sheath structure or the sheath portion of the fibers forming the core with the hollow structure is formed of a resin with a lower melting point than the core or the core with the hollow structure.

6. The heat insulating material for preventing dripping of condensation water according to any one of claims 1 to 5, characterized in that the nonwoven fabric formed on the surface of the resin foam is embossed.

7. 7. A piping system comprising a refrigerant pipe and a nonwoven fabric covering the outer periphery of the piping, the nonwoven fabric being coated on the outer periphery of the piping.

8. A spectacle-shaped piping structure characterized in that two pipes are integrated by facing each other and heat-sealing or heat-bonding the heat-insulating material for preventing condensation water dripping coated on the outer periphery of the refrigerant pipe as described in claim 7.

9. A cylindrical piping structure for refrigerant piping, characterized in that components to be installed inside a plurality of refrigerant pipes, drain pipes, and wiring pipes are prepared, and the condensation water drip prevention heat insulating material described in any one of claims 1 to 6 surrounds the plurality of refrigerant pipes, drain pipes, and wiring so that the nonwoven fabric forming surface forms the outer peripheral surface and the outer peripheral surface shape of the condensation water drip prevention heat insulating material has an approximately cylindrical cross section, thereby storing the components to be installed inside the piping inside the condensation water drip prevention heat insulating material.

10. A cylindrical piping structure for water supply and hot water supply, characterized in that a cross-linked polyethylene pipe and a resin sheath pipe that covers the outer periphery of the cross-linked polyethylene pipe are provided as piping for water supply and hot water supply, and the cross-linked polyethylene pipe and the resin sheath pipe that covers the outer periphery of the cross-linked polyethylene pipe are surrounded by a condensation water drip prevention insulation material described in any one of claims 1 to 6, with the nonwoven fabric forming surface as the outer periphery, and the cross-linked polyethylene pipe and the sheath pipe are stored inside the condensation water drip prevention insulation material so that the outer periphery shape of the condensation water drip prevention insulation material has an approximately cylindrical cross section.

11. 11. The cylindrical piping structure for hot and cold water supply piping according to claim 10, wherein the resin sleeve pipe is covered with a resin foam so as to surround the outer periphery of the sleeve pipe.

12. A piping structure in which the condensation water drip prevention insulation material is coated on the outer periphery of a refrigerant pipe, wherein at least a portion of the pipe includes a vertical pipe, and the nonwoven fabric forming surface of the condensation water drip prevention insulation material described in any one of claims 1 to 6 is coated on the vertical pipe so that it forms the outer periphery.

13. 7. A structure of an air conditioning duct, characterized in that the heat insulating material for preventing dripping of condensation water according to any one of claims 1 to 6 is adhered to the outer surface of the air conditioning duct with the nonwoven fabric surface facing the outer surface.

14. A structure for preventing condensation from dripping for inorganic building boards, characterized in that the heat-insulating material for preventing condensation from dripping according to any one of claims 1 to 6 is placed on the surface of an inorganic building board with the nonwoven fabric side facing outward, or further, the resin foam surface of the heat-insulating material for preventing condensation from dripping placed on the surface of the inorganic building board with the nonwoven fabric side facing outward and the surface of the inorganic building board are bonded to each other and arranged in a horizontal plane, and the inorganic building board is at least one of gypsum board and calcium silicate board.

15. A structure for preventing condensation from dripping on an inorganic building board, characterized in that the inorganic building board is arranged in a vertical plane direction, and the insulating material for preventing condensation from dripping according to any one of claims 1 to 6 is placed on the surface of the inorganic building board with the nonwoven fabric surface as the outer surface, and the resin foam surface of the insulating material for preventing condensation from dripping and the opposing surfaces of the surface of the inorganic building board are bonded to each other, and the inorganic building board is at least one of a gypsum board and a calcium silicate board.

16. A structure for preventing condensation water dripping from a folded plate roof, characterized in that the heat-insulating material for preventing condensation water dripping according to any one of claims 1 to 6 is adhered to the inner surface of the folded plate roof.

17. A nonwoven fabric in which the average fiber diameter of the fibers constituting the nonwoven fabric is in the range of 10 to 30 μm, the void ratio of the fibers of the nonwoven fabric is 85 to 98%, and the filling rate is 2 to 15%, and further, the thickness of the nonwoven fabric measured in accordance with JIS L1913 is 1.0 mm or less, and further, the effective tensile stress, which is the value obtained by dividing the apparent stress in the MD direction at a tensile elongation value of 5% in the same direction in a tensile test by a filling rate of 2 to 15%, satisfies the requirement of 1 MPa or more and 25 MPa or less, Furthermore, the water retention capacity of the nonwoven fabric converted into an apparent thickness of 1 mm is 500 g / m ２ A nonwoven fabric for preventing dripping of condensation water, which is disposed on the outer surface of a pipe, a heat exchanger or a building component and satisfies the above requirements.

18. The nonwoven fabric for preventing dripping of condensation water according to claim 17, characterized in that the ratio of effective tensile stress in the MD direction to that in the TD direction is 0.14 to 0.

94.

19. The nonwoven fabric for preventing dripping of condensation water according to claim 17, characterized in that the fibers constituting the nonwoven fabric are composed of fibers containing at least one of PET resin, polyethylene resin, polypropylene resin, and acrylic resin.

20. 20. The nonwoven fabric for preventing dripping of condensation water according to claim 19, wherein the fibers constituting the nonwoven fabric further contain 30% or less of any of cellulose fibers, pulp fibers, and rayon fibers by total fiber weight.

21. A nonwoven fabric for preventing dripping of condensation water as described in claims 17 to 20, characterized in that at least a portion of the fibers constituting the nonwoven fabric are composed of fibers having a core-sheath structure, or the core fibers of the fibers having a core-sheath structure are composed of fibers having a hollow core structure, and the nonwoven fabric is a hollow multilayer structure fiber in which a sheath portion is formed around the fibers forming the hollow core structure, and the sheath portion of the core-sheath structure or the sheath portion of the fibers forming the hollow core structure is formed from a resin with a lower melting point than the core portion.

22. A nonwoven fabric for preventing dripping of condensation water as described in claim 21, characterized in that at least a portion of the fibers constituting the nonwoven fabric are formed from short fibers, or from long fibers orthogonal to the weft and warp directions, or oblique to the weft and warp directions.

23. A nonwoven fabric for preventing dripping of condensation water, characterized in that the short fiber nonwoven fabric according to claim 22 is produced by a chemical bond method, a thermal bond method, a spunlace method, an airlaid method, or a needle punch method.

24. A nonwoven fabric for preventing dripping of condensation water as described in Claim 19 or 20, characterized in that the fibers are composed of fibers that do not have a core-sheath structure.

25. A method for constructing a piping structure in which the condensation-water drip prevention insulation material described in any one of claims 1 to 6 is wrapped around the outer periphery of a refrigerant pipe, and when the pipe is vertical or oblique, the method for forming a condensation-water drip prevention piping structure is characterized in that the condensation-water drip prevention insulation material is arranged in a horizontal direction perpendicular to the direction of the vertical pipe in such a way that the effective tensile stress of the condensation-water drip prevention insulation material satisfies the range of 25 MPa or less and 1 MPa or more.

26. A method for forming a drip-preventing structure for condensation water in an air conditioning duct, wherein the sides of the air conditioning duct are arranged opposite each other in at least a vertical direction so as to sandwich the top and bottom surfaces of the duct, and the nonwoven fabric of the drip-preventing heat insulation material for condensation water as described in any one of claims 1 to 6 is arranged on the sides in a horizontal direction perpendicular to the vertical duct side surfaces such that the effective tensile stress of the nonwoven fabric satisfies the range of 25 MPa or less and 1 MPa or more.

27. A method for forming a drip-preventing structure for condensation water in an inorganic building material for construction, wherein when the condensation structure of the inorganic building material for construction is a vertical wall structure, the method comprises arranging the nonwoven fabric of the heat-insulating material for preventing dripping of condensation water as described in any one of claims 1 to 6 as an outer surface on the surface of the vertical wall of the inorganic building material for construction, with the direction in which the effective tensile stress of the nonwoven fabric of the heat-insulating material for preventing dripping of condensation water satisfying the range of 25 MPa or less and 1 MPa or more being perpendicular to the direction of the vertical wall structure.

28. In a method for forming a structure for preventing dripping of condensation water from a corrugated plate roof, the nonwoven fabric of the condensation water drip prevention heat insulation material according to any one of claims 1 to 6 is arranged on the back surface of the corrugated plate roof as an outer surface, with the direction in which the effective tensile stress of the nonwoven fabric of the condensation water drip prevention heat insulation material of the nonwoven fabric of the condensation water drip prevention heat insulation material is 25 MPa or less and 1 MPa or more, perpendicular to the bending direction of the corrugated plates of the corrugated plate roof. A method for forming a structure for preventing dripping of condensation water from a corrugated plate roof, characterized in that the nonwoven fabric of the heat insulation material is arranged as an outer surface on the back surface of the corrugated plate roof.

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