JP2022177784A - Condensation water dropping-preventive heat insulator, condensation water dropping-preventive refrigerant piping and piping structure for water and hot-water supply using the same, and structure for condensation water dropping-preventive building, condensation water dropping-preventive nonwoven fabric, and method for forming condensation water dropping-preventive structure for refrigerant piping using the heat insulator and method for forming condensation water dropping-preventive structure for building member - Google Patents

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

The present invention provides a heat insulating material for preventing the dripping of condensed water, a refrigerant pipe for preventing the dripping of condensed water using the same, a piping structure for water supply and hot water supply, an architectural structure for preventing the dripping of condensed water, a non-woven fabric for preventing the dripping of condensed water, and the same. The present invention relates to a method for forming a structure for preventing dripping of condensed water for a refrigerant pipe using a heat insulating material, and a method for forming a structure for preventing dripping of condensed water for a building member.

Conventionally, a polyethylene or polypropylene film is attached to at least one surface of a polyethylene foam, and the surface of the attached resin foam is embossed. rice field. However, in the case of such a heat insulating material, condensation occurs on the surface of the heat insulating material used on the outer circumference of the refrigerant pipe, and the condensed water becomes water that drips into the piping space behind the ceiling. As a result, there was a problem of mold growing in the piping space such as the attic.

Patent Literature 1 describes a duct in which a nonwoven fabric is integrally formed with a duct body. A duct in which a non-woven fabric is integrally formed with a duct body, wherein the duct body is a foam blow molded body. Since the non-woven fabric is integrally molded with the duct body, which is a foam blow molding, dew condensation is less likely to occur on the surface of the duct body. is suppressed.

In the invention of Patent Document 1, the nonwoven fabric is molded integrally with the duct main body, so that the nonwoven fabric is suppressed from peeling off from the duct main body. Since the nonwoven fabric is integrally formed with the duct main body, the foam and the nonwoven fabric are not heat-sealed.

Patent Literature 2 describes an air-conditioning duct divided body composed of an internal layer made of a foam having a closed-cell structure and a non-woven fabric made of a thermoplastic resin. In this split body, the outer layer contains two kinds of thermoplastic resins with different melting points, and the resin layers with the lower melting point are bonded to each other by fusion. Furthermore, the divided body of the air-conditioning duct having a structure in which the foam of the inner layer and the two kinds of fibers forming the outer layer are adhered to each other with a hot-melt adhesive that can be bonded at a temperature lower than the melting point of the fiber on the low melting point side. is formed.

In addition, in this application, as the foam, a thermoplastic resin foam such as an olefin-based foam such as polyethylene or polypropylene, or a polyurethane foam can be used. It is described that a thermoplastic resin fiber made of a plastic resin is used, and a core-sheath structure is formed using resins having different melting points.

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

Patent Literature 3 discloses a heat insulating material in which a porous film and a nonwoven fabric are laminated, and the rate of absorption of water droplets dropped on the film surface is within 60 seconds. Common natural fibers such as cotton, hemp, and wool can be used for the fibers of the non-woven fabric. Regenerated fibers, such as rayon and acetate, are preferred for use as the heat insulating material for food, and synthetic fibers, such as polyethylene, polypropylene, and polyethylene terephthalate, can be used because of their low cost.

A feature of the present invention is that the above fibers contain 1 to 10% of fibers made of a crosslinked product of hydrophilic sodium polyacrylate as water-absorbing fibers. Further, it is described that the nonwoven fabric has a thickness of 0.3 to 3 mm (0.5 to 1.5 mm) and a basis weight of 20 to 250 g/m ² , more preferably 50 to 150 g/m ² . It is stated that

By using a special water-absorbent resin, the water retention capacity of the sheet is improved, but there is a problem of increased cost, and the base material of the non-woven fabric is not a foam but a resin film, so there is a problem of insufficient heat insulation. be.

Patent Literature 4 discloses a method of forming an embossed sheet in which an embossed pattern is continuously engraved on a laminated sheet formed by adhering a resin foam sheet and a resin film.
In the present invention, an embossing roll having a pattern of mutually adjacent concave portions is pressed against the resin film and rotated to form an air reservoir for storing air when the embossing roll is pressed against the sheet. , an embossing roll in which convex portions are formed on the bottom surface of concave portions, and an embossed sheet manufactured by this roll are disclosed. Furthermore, a pipe cover is disclosed which is characterized by being formed into a cylindrical shape so that the embossed pattern is positioned on the outer surface.

JP 2020-197315 A JP 2014-065382 A JP-A-9-300511 JP-A-9-314661

Until now, it was known that it was possible to prevent the dripping of condensed water by attaching a nonwoven fabric to the surface of the heat insulating material. It is not enough to just place it on the surface, and it has been clarified that the nonwoven fabric itself must have a specific structure regardless of the material of the nonwoven fabric. was the subject.

Originally, the water absorption and dew condensation characteristics of a nonwoven fabric should differ depending on the material and structure of the nonwoven fabric. No mention of gender. In Patent Document 3, a special water-absorbent resin such as a cross-linked product of sodium polyacrylate is used. A non-woven fabric having a predetermined structure is placed on the surface of a polyethylene resin foam that can prevent the dripping of condensed water, regardless of whether the regenerated fiber material having water absorption is used. It is used as a heat insulating material for prevention.

The heat insulating material for preventing dripping of condensed water of the present invention is obtained by fusing or adhering a nonwoven fabric having a predetermined structure to at least one surface of a polyethylene-based resin foam. The present invention provides a heat insulating material for preventing the dripping of condensed water, a refrigerant pipe for preventing the dripping of condensed water using the same, a piping structure for water supply and hot water supply, an architectural structure for preventing the dripping of condensed water, a non-woven fabric for preventing the dripping of condensed water, and the same. The present invention relates to a method for forming a structure for preventing dripping of condensed water for a refrigerant pipe using a heat insulating material, and a method for forming a structure for preventing dripping of condensed water for a building member.

Here, in order to prevent dripping of condensed water in such a piping structure, a non-woven fabric is attached to a foam that is a heat insulating material so that the condensed water is supported inside the non-woven fabric. may be preventable. However, it is not possible to simply prevent dripping of condensed water by laminating a nonwoven fabric on the surface of a foam. The porosity of the fiber, the degree of bending of the fiber, the structure of the connecting part of the fiber, the three-dimensional structure of the fiber such as the entanglement of the fiber, etc. have an effect, but the structure of the nonwoven fabric is untidy, so it should be specified directly. However, the present invention was accomplished by finding and defining an alternative parameter that reflects the influence of the complex structure of the nonwoven fabric on the dripping property of condensed water.

In addition, in the present invention, as factors for defining the structure of the nonwoven fabric used as a heat insulating material, the spatial structure of the fiber is defined based on the fiber diameter of the nonwoven fabric used and the porosity of the fiber at a predetermined thickness. It has been found that a fiber having a large number of bent portions and a high crimpability is excellent in the drip prevention property of dew condensation water. In addition, as parameters for evaluating the three-dimensional structure including the crimpability of this fiber, the structure of the connection part of the fiber, the degree of entanglement of the fiber, etc., the tensile modulus value at a predetermined strain in the tensile test and the drip prevention property was found to be correlated with As for the water retention property based on the above structure, the water retention amount per predetermined nonwoven fabric thickness was evaluated, and it was confirmed that a nonwoven fabric having a predetermined water retention amount or more is excellent in the drip prevention property of condensed water. Here, the tensile modulus refers to the effective tensile stress value obtained by dividing the apparent tensile stress in the same direction when the tensile elongation value in the predetermined direction is 5% in the tensile test by the filling ratio, but the predetermined tensile modulus value or the effective tensile stress The value satisfies a predetermined value means that the effective tensile stress, which is the value obtained by dividing the apparent tensile stress in the same direction when the tensile elongation value in the predetermined direction in the tensile test is 5% by the filling rate, satisfies 25 MPa or less and 1 MPa or more. Say. That is, the tensile modulus and the effective tensile stress value are synonymous. The apparent tensile stress is the value obtained by dividing the apparent tensile load by the cross-sectional area of the nonwoven fabric defined from the apparent thickness of the nonwoven fabric measured according to JISL1913 and the width of the test piece.

Further, the nonwoven fabric of the present invention is fused or adhered to a base polyethylene resin foam to form a heat insulating material, and then embossed into a predetermined shape. Since it was considered that the filling rate and tensile modulus value were particularly affected, the formability in embossing was confirmed.

In addition, even if the fibers used for the non-woven fabric are polyethylene resin, polypropylene resin, PET, or other resins that do not absorb water, the non-woven fabric can have a high water retentivity if it satisfies predetermined structural conditions. Furthermore, the inventors have discovered that the dew condensation water drip prevention performance is excellent, and have completed the present invention.

Of course, if the nonwoven fabric satisfies predetermined structural conditions, it is also possible to use water-absorbing natural fibers such as cellulose and pulp, regenerated fibers such as rayon and acetate, and semi-synthetic fibers within a predetermined amount range. . In this case, compared to the case of using non-water-absorbing resin fibers such as polyethylene resin, polyethylene resin, polyester PET, etc., the ability to prevent dripping of condensed water is further improved, but the strength of the non-woven fabric is reduced, so the water-absorbing property is reduced. The use of synthetic fibers should be limited to a certain amount of the total fiber weight. In particular, when natural fibers such as cellulose fibers and pulp are used for the non-woven fabric, it is difficult to produce long fibers due to the characteristics of natural fibers, and the fiber length is not stable, so it is desirable to use short fibers. .

Since the present invention is secured by the non-woven fabric used for the heat insulating material, the present invention includes a heat insulating material for preventing dripping of condensed water, a pipe structure for preventing dripping of condensed water using the same, and a construction for preventing dripping of condensed water. In addition to the structure, we have also invented a non-woven fabric for preventing dripping of condensed water. In addition, inventions of a method for forming a refrigerant pipe structure using this heat insulating material and a structure for preventing dripping of condensed water from building members are also added.

A heat insulating material for preventing dripping of condensed water in which a nonwoven fabric is arranged on the surface of a polyethylene resin foam, the base material is a polyethylene resin foam having sheet-like closed cells, and one surface of the base material has The nonwoven fabric is fused or bonded, 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 is 85 to 98%, and the nonwoven fabric is measured in the MD direction in a tensile test. The effective tensile stress, which is the value obtained by dividing the apparent stress in the same direction at a tensile elongation value of 5% by the filling rate, satisfies 25 MPa or less and 1 MPa or more. It is sufficient that the effective tensile stress in the MD direction satisfies 25 MPa or less and 1 MPa or more, and the effective tensile stress in the TD direction may or may not necessarily satisfy the range of 25 MPa or less and 1 MPa or more. Here, the thickness of the polyethylene-based resin foam should be at least 10 mm or more in order to ensure the heat insulating properties. Conversely, if the thickness of the foam is too thick, the product dimensions such as the product thickness and the product diameter after covering with the heat insulating material will increase, so 10 mm is desirable.

At this time, the average fiber diameter of the fibers is in the range of 10 to 30 μm. This is because when the nonwoven fabric and the foam are thermally fused, the nonwoven fabric itself is deformed and the elastic recovery after fusion becomes insufficient, and at the same time, the fibers fall down and are fused in a plane. On the other hand, if the fiber diameter exceeds 30 μm, the space occupation ratio of the fiber itself increases due to the increase in fiber diameter, and it becomes difficult to form a three-dimensionally stable space with a high porosity. This is because it becomes difficult to keep the porosity in the range of 85 to 98%. Here, when the nonwoven fabric is composed of a plurality of fibers, the average fiber diameter referred to in the present invention preferably satisfies the above range for the average fiber diameter of each constituent fiber. The diameter (number average) satisfies the above range.

Here, looking at the porosity, if the porosity is less than 85%, the proportion of fibers in the unit volume will increase, so it will not be possible to exhibit a sufficient water retention capacity. . On the other hand, when the porosity exceeds 98%, although the space for forming the water film increases, the water film cannot be maintained, and the water retention decreases. Decrease in sexuality, etc.

Further, since the tensile modulus (effective tensile stress) is a value obtained by dividing a normal tensile stress value by the filling rate, it is a value that excludes the influence of the filling rate (porosity) of fibers. From this, it is considered that the value comprehensively includes information on crimpability of the fibers themselves in the nonwoven fabric and information on the degree of orientation of the fibers in the nonwoven fabric. This is because, if the porosity is the same, the more crimped the fibers and the smaller the orientation, the smaller the distance between the three-dimensionally adjacent fibers, so the nonwoven fabric absorbs more water. It is an important parameter because it can be considered to hold. In fact, when the effective tensile stress exceeds 25 MPa, the rigidity of the nonwoven fabric increases and the water retention decreases, resulting in insufficient water retention and embossability, which is not preferable. Also, when the effective tensile stress in both the MD and TD directions is less than 1 MPa, although there is sufficient space to hold the condensed water, the bonding and entanglement of the fibers inside the nonwoven fabric becomes insufficient. The retainability cannot be guaranteed, and the handling becomes difficult in terms of the manufacturing process of the present invention. Therefore, it is considered that the effective tensile stress in at least one direction must exceed 1 MPa.

The nonwoven fabric of the heat insulating material may have a thickness of 1.0 mm or less as measured according to JISL1913, and a water retention capacity of 500 g/m ² or more per 1 mm of apparent thickness of the nonwoven fabric.

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. Further, the fibers constituting the nonwoven fabric of the heat insulating material may further contain any one of cellulose, pulp, and rayon fibers in an amount of 30% or less of the total weight of the fibers in addition to the above fibers. Further, the total fiber weight is more preferably 15% or less in terms of nonwoven fabric strength. When using natural fibers, it is difficult to obtain long fibers, so it is preferable to use short fibers.

At least part of the fibers constituting the nonwoven fabric of the heat insulating material includes fibers having a core-sheath structure, and the sheath of the fibers having the core-sheath structure is formed of a resin having a lower melting point than the core, Alternatively, the core fiber of the core-sheath structure is a hollow fiber, the hollow multi-layer structure fiber has a sheath formed around the hollow fiber, and the core or the sheath of the fiber forming the hollow core is It may be made of a resin having a melting point lower than that of the core. By forming the core into a hollow structure, the flexibility of the nonwoven fabric can be improved. At least part of the fibers constituting the nonwoven fabric may be formed of staple fibers, or may be nonwoven fabrics formed of long weft or weft orthogonal filaments or weft or weft oblique filaments.

Further, the non-woven fabric formed on the surface of the resin foam may be embossed to prevent dripping of condensed water. By performing embossing in this way, the shape of the outer surface of the nonwoven fabric can be stabilized, and the shape stability when the nonwoven fabric is wound around pipes, ducts, or the like can be increased.

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

That is, it is more desirable that the effective tensile stress value obtained by dividing the apparent stress at a tensile elongation value of 5% in the MD direction and the TD direction in the tensile test by the filling rate is 20 MPa or less and 1 MPa or more. More preferably, the effective tensile stress value obtained by dividing the apparent stress at 5% by the filling ratio in a tensile test in either the MD direction or the TD direction is 20 MPa or less and 2 MPa or more. By satisfying these characteristics, it is possible to obtain a heat insulating material that satisfies the prescribed values of the effective tensile stress in both the MD and TD directions. Since it is possible to obtain a heat insulating material having excellent drip prevention performance, dripping of condensed water can be prevented even when the heat insulating material is used in the vertical direction.

The piping may be characterized in that the heat insulating material for preventing dripping of condensed water is coated with a non-woven fabric on the outer circumference of the refrigerant piping or the hot water piping. By doing so, it is possible to improve the heat retention of the piping and prevent dew condensation.

A pair of spectacle-shaped pipes are integrated by heat-sealing or heat-bonding the heat insulating materials for preventing dripping of condensed water coated on the outer circumference of the refrigerant pipes to face each other. It is a piping structure.

A plurality of refrigerant pipes, drain pipes, and wiring pipes are internally provided with parts, and the outer peripheral surface of the heat insulating material for preventing dripping of condensed water has a non-woven fabric forming surface as an outer peripheral surface. By enclosing the plurality of refrigerant pipes, drain pipes, and wiring so that the cross section has a substantially cylindrical shape, the components inside the pipes are housed inside the heat insulating material for preventing dripping of condensed water. It may be a cylindrical piping structure of the refrigerant piping that is characterized. Such a piping structure may be a cylindrical piping structure for a refrigerant pipe that can collectively heat a plurality of pipes and prevent dew condensation.

A crosslinked polyethylene pipe and a resin sheath pipe covering the outer periphery of the crosslinked polyethylene pipe are prepared as a water supply pipe, and the condensed water is dripped around the crosslinked polyethylene pipe and the resin sheath pipe covering the outer periphery of the crosslinked polyethylene pipe. The crosslinked polyethylene pipe and the crosslinked polyethylene pipe are placed inside the heat insulating material for preventing dripping of dew condensation water so that the non-woven fabric forming surface is the outer peripheral surface of the heat insulating material, and the outer peripheral surface shape of the heat insulating material for preventing dripping of dew condensation water is approximately cylindrical in cross section. It may be a tubular pipe structure of a hot water supply pipe that accommodates the sheath pipe.

The resin sheath pipe may have a tubular pipe structure of a water supply and hot water supply pipe covered with a resin foam so as to surround the outer circumference of the sheath pipe.

A pipe structure in which the outer periphery of the refrigerant pipe is covered with the heat insulating material to prevent dripping of condensed water, wherein at least a part of the pipe includes a vertical pipe, and the vertical pipe is formed of a non-woven fabric of the heat insulating material to prevent dripping of condensed water. The pipe structure may be a vertical pipe covered with the vertical pipe so that the surface is the outer peripheral surface. Here, the protective member for preventing dripping of condensed water wound around the vertical pipe has an average fiber diameter in the range of 10 to 30 μm, the porosity of the fiber is 85 to 98%, and the tensile elongation values in the MD and TD directions are It is preferable that the nonwoven fabric satisfies the value obtained by dividing the apparent stress in the same direction at 5% by the filling ratio of 20 MPa or less and 1 MPa or more.

The air-conditioning duct may have a structure in which the heat insulating material for preventing dripping of condensed water is adhered to the outer surface of the air-conditioning duct with the non-woven fabric forming surface facing the outer surface. By covering the outer periphery of the air-conditioning duct with the heat insulating material for preventing dripping of condensed water in this way, it is possible to improve the heat insulation of the air-conditioning duct and prevent condensation on the outer periphery of the duct. At this time, the nonwoven fabric adhered to the outer peripheral surface of the air conditioning duct has an effective tensile stress, which is the value obtained by dividing the apparent stress in the same direction when the value of tensile elongation in the MD and TD directions in the tensile test is 5% by the filling rate. It is desirable that the non-woven fabric satisfies a viscosity of 25 MPa or less and 1 MPa or more.

The heat insulating material for preventing the dripping of condensed water is placed on the surface of the inorganic building board with the nonwoven fabric forming surface as the outer surface, or further placed on the surface of the inorganic building board with the nonwoven fabric forming surface as the outer surface. the resin foam surface of the heat insulating material for preventing dripping of condensed water and the surface of the inorganic building board are adhered to each other and arranged in the horizontal direction, and the inorganic The construction board material may be a gypsum board or a calcium silicate board, and may be a structure for preventing dripping of condensed water of an inorganic building board material.

The heat insulating material for preventing dripping of condensed water is placed on the surface of the inorganic building board with the non-woven fabric forming surface as the outer surface, and the resin foam surface of the heat insulating material for preventing dripping of condensed water and the inorganic building board. The inorganic building board material having the surfaces facing each other bonded to each other is arranged in a vertical plane direction, and the inorganic building board material is at least one of a gypsum board and a calcium silicate board. It may be a drip prevention structure for dew condensed water of a system building plate material.

At this time, the inorganic building board is arranged in the vertical plane direction, and the nonwoven fabric adhered to the outer peripheral surface of the inorganic building board has a tensile elongation value of 5% in the MD and TD directions in a tensile test. It is desirable that the nonwoven fabric satisfies the effective tensile stress of 25 MPa or less and 1 MPa or more, which is the value obtained by dividing the apparent stress in the same direction at the filling rate.

A structure for preventing dripping of condensed water may be provided for a folded-plate roof in which the heat insulating material for preventing dripping of condensed water is adhered to the inner surface of the folded roof. By adhering the heat insulating material for preventing dripping of condensed water to the inner surface of the folded plate roof in this way, it is possible to improve the heat insulating properties 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 for the drip prevention structure of the condensed water of the folded plate roof is a nonwoven fabric that satisfies predetermined values of tensile modulus in both the MD direction and the TD direction similar to the air conditioning duct.

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 is 85 to 98%, and the thickness of the nonwoven fabric measured based on JISL1913 is 1.0 mm or less. Further, it may be a nonwoven fabric for preventing dripping of condensed water that satisfies the value obtained by dividing the apparent stress in the same direction at a tensile elongation value of 5% in the MD direction in a tensile test by the filling rate of 25 MPa or less and 1 MPa or more. .

A non-woven fabric for preventing dripping of condensed water, wherein the non-woven fabric is fused to the surface of a polyethylene-based resin foam, wherein the non-woven fabric has a water retention capacity of 500 g/m ² or more per 1 mm of apparent thickness of the non-woven fabric. There may be.

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

Further, the nonwoven fabric for preventing dripping of condensed water comprises at least part of the fibers having a core-sheath structure, and in the case of having a core-sheath structure, the sheath is made of a resin having a lower melting point than the core. Further, it may be a hollow multi-layer structure fiber in which the core fiber of the core-sheath structure is a hollow fiber and a sheath is formed around the hollow fiber. By forming the core into a hollow structure, it is possible to ensure the flexibility of the nonwoven fabric.

The nonwoven fabric has an effective tensile stress of 25 MPa or less and 1 MPa or more, which is the value obtained by dividing the apparent stress in each direction when the value of tensile elongation in the MD direction and TD direction in a tensile test is 5%, divided by the filling rate. It is also possible to provide a nonwoven fabric for preventing dripping of condensed water that satisfies both requirements. By satisfying these characteristics, it is possible to obtain a non-woven fabric for preventing dripping of condensed water that is excellent in preventing dripping of condensed water in both directions or has the ability to prevent dripping of condensed water regardless of the installation direction.

The fibers constituting the nonwoven fabric are composed of short fibers containing at least one or more of PET resin, polyethylene resin, polypropylene resin, or acrylic resin, and the short fibers are fibers that do not have a normal core-sheath structure, or at least one The non-woven fabric for preventing dripping of condensed water may be made of fibers in which the portion is composed of fibers having a core-sheath structure, and in the case of having a core-sheath structure, the sheath portion is made of a resin having a lower melting point than the core portion. . Further, the fibers constituting the nonwoven fabric may further contain any one of cellulose fibers, pulp and rayon fibers in an amount of 30% or less of the total weight of the fibers. Here, the reason why the content of the water-absorbing fibers is set to a predetermined value or less is to prevent a decrease in strength due to an increase in the amount of water supplied.

In this way, by using a non-melting type fiber in which the sheath is formed of a resin with a lower melting point than the core, by heat-sealing in a lower temperature range than the core with a higher melting point, Also, the physical properties and mechanical properties of the core fiber can be maintained. Further, by making the core part hollow, the flexibility of the nonwoven fabric can be improved.

The nonwoven fabric of short fibers can be a nonwoven fabric manufactured by chemical bond method, thermal bond method, spunlace method, air laid method, needle punch method, or the like. By using at least a part of the staple fibers produced by such a production method in the nonwoven fabric, dew condensation can be prevented even when the nonwoven fabric is used not on a horizontal surface but in a vertical direction. As a nonwoven fabric that can reduce the influence of fiber orientation without using short fibers, a crosswise crosswise nonwoven fabric or a crosswise crosswise nonwoven fabric can also be used.

A construction method for a piping structure in which the heat insulating material for preventing dripping of condensed water is wound around the outer periphery of a refrigerant pipe, and when the pipe is a vertical pipe or an oblique pipe, the heat insulating material for preventing dripping of condensed water is effective. A method for forming a pipe structure may be employed in which a direction satisfying a tensile stress of 25 MPa or less and 1 MPa or more is oriented in a horizontal direction perpendicular to the direction of the vertical pipe.

Here, when the piping for preventing dripping of condensed water is a vertical piping or an oblique piping, if the length of the piping in the vertical direction is long, transpiration from the surface of the nonwoven fabric and accumulation of moisture in the nonwoven fabric will occur under the influence of gravity. However, since there is a possibility of condensation water dripping from the bottom of the pipe, the effective tensile stress in the TD direction is increased so as to accelerate the transpiration from the surface of the nonwoven fabric by promoting the movement to the side of the nonwoven fabric. It is conceivable that the improvement will promote the transpiration from the surface of the nonwoven fabric and prevent the dripping of condensed water.

In the method of forming a structure for preventing dripping of condensed water in an air-conditioning duct, side surfaces of the air-conditioning duct are provided facing each other so as to sandwich an upper surface and a lower surface of the duct in at least a vertical direction. Condensed water in an air-conditioning duct in which the nonwoven fabric surface of the nonwoven fabric of the water dripping prevention heat insulating material is arranged as the outer surface in a direction that satisfies the effective tensile stress of 25 MPa or less and 1 MPa or more in the horizontal direction perpendicular to the vertical side of the duct. It may be a method for forming a drip prevention structure.

In the method for forming a structure for preventing dripping of condensed water from inorganic building materials for construction, when the structure for preventing condensation from dripping from inorganic building materials for construction is a vertical wall structure, the effective tensile stress of the nonwoven fabric of the heat insulating material for preventing dripping of condensed water 25 MPa or less and 1 MPa or more, and the non-woven fabric of the heat insulating material is arranged as the outer surface on the surface of the vertical wall of the inorganic building material for construction with the direction satisfying the horizontal direction perpendicular to the direction of the vertical wall structure. It is desirable to provide a method for forming a structure for preventing dripping of condensed water from an inorganic building material. In the method for forming a structure for preventing dripping of condensed water on a folded plate roof, the folded plate of the folded plate roof is bent in a direction in which the effective tensile stress of the nonwoven fabric of the heat insulating material for preventing the dripping of condensed water satisfies 25 MPa or less and 1 MPa or more. It is desirable that the method of forming a structure for preventing dripping of condensed water on a folded-plate roof arranges the non-woven fabric of the heat insulating material on the back surface of the folded-plate roof in a direction perpendicular to the direction of the folding-plate roof. At this time, since the slope of draining water when laying a folded plate roof is usually about 3/100, there is almost no effect on dripping of condensed water.

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

Here, if the above heat insulating material is used, the thickness of the nonwoven fabric measured based on JISL1913 is 1.0 mm or less, and the water retention amount converted per 1 mm of apparent thickness of the nonwoven fabric satisfies 500 g / m ² or more. be able to. Since the ability to prevent dripping of condensed water in the present invention can be obtained regardless of the water absorbency of the fibers themselves, both chemical fibers and natural fibers can be used as the fibers that make up the nonwoven fabric. can. In addition, in addition to the porosity and tensile modulus as parameters that indirectly reflect the three-dimensional structure of the fiber, the nonwoven fabric of the present invention also has a fiber diameter within a predetermined range, so not only does it prevent dripping of condensed water. It is also characterized by excellent embossability. It is preferable that the non-woven fabric is joined to the foam in the heat insulating material of the present invention by fusion, but it may be arranged by joining by adhesion.

Here, the dew condensation prevention mechanism of the heat insulating material of the present invention is considered as follows. First, when microscopic condensation occurs at the interface between the foam and the nonwoven fabric, the microcondensed water diffuses in the thickness direction due to the capillary action of the nonwoven fabric. Since the moisture diffused in the thickness direction has a large contact area with the outside air, it is easily warmed by the outside air, thereby suppressing the continuation of the dew condensation phenomenon and the increase in the size of water droplets due to minute dew condensation water.

Moreover, it is thought that dew condensation is suppressed because the dew condensation water diffuses and evaporates from the surface of the nonwoven fabric. At this time, by setting the fiber diameter and porosity to a predetermined value, the value obtained by dividing the stress at the 5% tensile elongation value by the filling rate is set to a predetermined range, thereby preventing dripping of condensed water and maintaining a predetermined water retention amount. It can be a non-woven fabric that retains moisture. Further, even if the fiber diameter and the empty rate satisfy the predetermined values, if the value obtained by dividing the stress at the 5% tensile elongation value by the filling rate does not satisfy the predetermined range, dew condensation cannot be prevented. It will be.

In addition to the above, when a nonwoven fabric is wrapped around a pipe, the nonwoven fabric wrapped around the outer periphery of the heat insulating material with a substantially cylindrical cross section has a higher vertical direction than the case where the nonwoven fabric of the heat insulating material is used in a flat shape. Since there is a difference in height, the water content in the non-woven fabric above and below the piping structure covered with heat insulating material around the pipes changes due to the suction movement effect due to capillary action and the downward movement of moisture due to gravity. A corresponding gradient occurs and the water content in the lower part of the pipe is higher than that in the upper part.

For example, in the case of horizontal piping, since the amount of water on the upper surface of the pipe is small, the contact area with the atmosphere is large, and water evaporates from the upper surface of the pipe, and water is absorbed from the lower surface of the pipe to the upper surface due to capillary action. is performed, and by maintaining a predetermined relationship between evaporation and water absorption, dew condensation from the piping can be prevented. In addition, in the case of vertical pipes or vertical walls where there is a difference in the covering state of heat insulating material, the effect of gravity is greater than in the case of horizontal pipes, so it is necessary to consider the effect of gravity on the occurrence of condensation. This problem can be solved if the moisture retained in the nonwoven fabric can be released in the horizontal direction by capillarity to increase the contact area with the air and accelerate the evaporation of the condensed water.

That is, the nonwoven fabric of the present invention is constructed in a direction in which the value obtained by dividing the apparent stress in the same direction at a tensile elongation value of 5%, which is a predetermined value in the tensile test, by the filling rate satisfies 25 MPa or less and 1 MPa or more. The effective tensile stress value satisfies the specified value even if the nonwoven fabric is constructed so that it matches the horizontal direction of the time, or the nonwoven fabric is constructed so that either the MD direction or the TD direction of the nonwoven fabric coincides with the horizontal direction. If a nonwoven fabric with improved anisotropy that does not cause the problem of dew condensation can be used, it will be possible to solve the problem of dew condensation on heat insulating materials, and it will be possible to provide a nonwoven fabric that can prevent dew condensation. Needless to say, even in this case, the fiber diameter and porosity of the nonwoven fabric to be used must satisfy the ranges of the present invention, namely, an average fiber diameter of 10 μm to 30 μm and a porosity of 85 to 95%.

By covering the outer periphery of the refrigerant pipe with the heat insulating material for preventing dripping of condensed water, a pipe structure for preventing dripping of condensed water can be obtained, and the heat insulating material for preventing dripping of condensed water is applied to the outer peripheral surface of the air conditioning duct. An air-conditioning duct that prevents dripping of condensed water can be obtained by using an air-conditioning duct that is adhered or covered. In addition, it is possible to obtain a structure for preventing the dripping of condensed water from an inorganic building board in which a heat insulating material for preventing the dripping of condensed water is arranged on the surface of the inorganic building board. It is possible to obtain a structure for preventing dripping of condensed water of the inorganic building board material in which the inorganic building board material arranged on the surface of the inorganic building board material is arranged as a vertical wall. A folded-plate roof structure that prevents dripping of condensed water can be obtained by adhering to the inner surface of the folded-plate roof. As a matter of course, it is possible to obtain the nonwoven fabric itself which is excellent in water retention and drip prevention performance of condensed water.

ADVANTAGE OF THE INVENTION According to this invention, in the thermal insulation material which arrange|positioned the nonwoven fabric on the surface of the polyethylene-type resin foam, the drip prevention property of dew condensation water can be improved irrespective of the material of a nonwoven fabric.

(a) is a diagram showing the test condition of the dew condensation test material using a constant temperature and humidity chamber, and (b) is a diagram showing the winding condition of the heat insulating material for preventing dripping of condensed water around the refrigerant pipe. FIG. 2(a) shows a perspective view of a pipe covered with a heat insulating material 3 for preventing dripping of condensed water wound around the outer circumference of the refrigerant pipe, and FIG. 2(b) shows a straight line from FIG. Shown is a cross-sectional view cut at a given position including XX. FIG. 3(a) shows a pipe structure in which pipes coated with a heat insulating material for preventing dripping of condensed water according to the present invention are opposed to each other and integrated, and FIG. 3(b) shows 4 shows a cross-sectional view of FIG. 3(a) cut at a predetermined position including a straight line AA. FIG. 4 shows a tubular refrigerant piping structure in which the existing refrigerant piping is surrounded by the heat insulating material of the present invention. FIG. 5(a) shows a tubular pipe structure for water and hot water supply, in which the protection member of the present invention is arranged on the outer periphery of the pipe for water and hot water supply, in which the outer periphery of the pipe is covered with a resin sheath pipe for protecting the pipe. FIG. 5(b)(c) shows a tubular pipe structure for hot and cold water supply in which the outer periphery of a resin sheath 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. (d) in the figure is a cross-sectional view cut at a predetermined position including the straight line BB in the perspective view (c). FIG. 6 shows a piping structure in which the protection member of the present invention is applied to vertical piping. FIG. 7 shows a structure for preventing dripping of condensed water in a duct using the heat insulating material of the present invention. FIG. 8(a) shows a structure for preventing dripping of condensed water of an inorganic building board material in which a heat insulating material for preventing dripping of condensed water is arranged on the surface of the inorganic building board material, and FIG. 1 shows a structure for preventing dripping of condensed water of an inorganic building board material in which a heat insulating material for preventing dripping of water is arranged on the surface of the inorganic building board material and the inorganic building board material is arranged as a vertical wall. FIG. 9 shows a folded-plate roof structure obtained by bending a steel plate in which the nonwoven fabric of the heat insulating material of the present invention is laminated on the lower surface of the steel plate of the folded-plate roof. FIG. 10(a) is a 100-fold SEM photograph of the non-woven fabric 4 excellent in preventing dripping of condensed water. FIG. 10(b) is an optical microscope photograph at 100 times after water absorption of the nonwoven fabric 4 excellent in drip prevention of condensed water. SEM photograph of the non-woven fabric made of diagonal fibers of test material 19 at a magnification of 100. FIG. SEM photograph of a nonwoven fabric using short fibers corresponding to test material 18. FIG.

DETAILED DESCRIPTION OF THE INVENTION Embodiments for carrying out the present invention will be described in detail below.

The heat insulating material for preventing dripping of condensed water of the present invention has a base material made of polyethylene resin foam having closed cells, and a nonwoven fabric is provided on at least one surface of the polyethylene resin foam and on the surface of the resin foam. It is a heat insulating material that satisfies the function of preventing dripping of condensed water because the nonwoven fabric satisfies a predetermined configuration.

A cross-linking foaming method is used as a method for producing a polyethylene-based foam that constitutes the base material of the heat insulating material for preventing dripping of condensed water of the present invention. An extrusion cross-linking foaming method can be used in which cross-linking is performed by extrusion and foaming is performed after cross-linking.

(polyethylene resin foam)
A polyethylene resin such as LDPE, HDPE, or the like, or a mixed resin of LDPE and HDPE can be used as the resin used for the polyethylene-based foam.

Moreover, heat resistance and flame retardancy can be imparted to these polyethylene-based foams as necessary. When a mixed resin of LDPE and HDPE is used, a mixed resin can be obtained by mixing LDPE and HDPE in a predetermined mixing ratio and LDPE and HDPE in a predetermined mixing ratio, for example, 40 parts by weight of LDPE and 60 parts by weight of HDPE. . In addition, in the present invention, as will be described later, a heat resistance improver or a flame retardant can be added to make the polyethylene resin foam heat-resistant or flame-retardant. In addition to the above, polyethylene-based resin foams containing various additives can be used as long as they do not inhibit the foamability or cause deterioration of the resin.

As the polyethylene-based resin, in addition to LDPE and HDPE, a modified polyethylene-based resin such as EVA (vinyl acetate copolymerized polyethylene) can be used. EVA is used in place of polyethylene because of its high flexibility and elasticity, allowing it to be used in a wide 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.

(crosslinking agent, foaming agent, etc.)
Here, the contents of the cross-linking agent and the foaming agent used in the polyethylene-based foam are, for example, when the expansion ratio is 20-40 times, the cross-linking agent is 0.6-1.0 parts per 100 parts by mass of the polyethylene-based resin. It may be contained in the range of 5 parts by weight, and the foaming agent may be contained in the range of 10 to 30 parts by weight. Although the above range is desirable for the cross-linking agent and the foaming agent, it is possible to change them as necessary.

For example, dicumyl peroxide or the like can be used as a cross-linking agent. For example, as dicumyl peroxide as a cross-linking agent, NOF Co., Ltd. trade name Permil D can be used. Also as a blowing agent. Although an inorganic foaming agent may be used, azodicarbonamide (ADCA), which is an organic decomposition type foaming agent, such as Vinihole AC#LQ (trade name, manufactured by Eiwa Chemical Co., Ltd.), can be preferably used.

As blowing agents, in addition to azodicarbonamide (ADCA), oxybisbenzenesulfonylhydrazide (OBSH), N,N'-dinitrosopentamethylenetetramine (DPT), p-toluenesulfonylhydrazide, benzenesulfonylhydrazide, diazoaminobenzene , N,N'-dimethyl-N,N'-dinitroterephthalamide, azobisisobutyronitrile and the like can be used, and these can be used alone or in combination of two or more. Any of these blowing agents may be used. Usually, azodicarbonamide (ADCA) is often used as a blowing agent.

In addition to the above, a cross-linking aid and a foaming aid can be added as necessary. For example, TMPT (trimethylolpropane trimethacrylate) trade name: Ogmont may be added as a cross-linking aid, and zinc oxide may be used as a foaming aid.

(Heat resistance improver, flame retardant)
When imparting heat resistance, at least one or both of carbon or titanium oxide (rutile type) heat-resistant pigments should be added in a total amount of 2.0 parts by mass or less to 100 parts by mass of the resin. can be done. Carbon has high conductivity and therefore has a heat dissipation effect, titanium oxide has excellent heat reflectivity, and both carbon and titanium oxide have high heat resistance, so that the heat resistance of the resin foam can be improved.

In addition, in order to improve the flame retardancy of the foam, a flame retardant is added. A total of 100 parts by mass of a physical flame retardant, a brominated flame retardant, and the like can be added. In addition to the antimony-based flame retardants, brominated flame-retardants, and hydroxide-based flame retardants described above, inorganic fillers may also be added.

For example, if the content of the flame retardant exceeds 100 parts by mass, the effect saturates and foamability is inhibited, so the total amount of the flame retardant added is 100 parts by mass or less. If the content of the flame retardant exceeds 100 parts by mass, the flame retardant inhibits foamability, so the upper limit should be 100 parts by mass or less. Here, the preferred content of the antimony flame retardant and the brominated flame retardant is 20 parts by mass or less, respectively, and the preferred content of the hydroxide flame retardant is 80 parts by mass or less. In addition, since the specific gravity of any flame retardant is larger than that of the resin component, the mixing ratio to the resin component is significantly smaller than the mass ratio when converted to the mixing volume ratio. There is no particular problem.

(Inorganic filler)
Inorganic fillers can be contained within a range that does not impair foamability, impact resistance, and fire resistance (uniformity of thickness of carbonized layer). 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. If the content of the inorganic filler is too large, the foamability is inhibited, so it is preferable that at least one of the inorganic fillers can be contained in an amount of 2 parts by mass or less. Furthermore, the content of these inorganic fillers is desirably 1 part by mass or less.

(Antioxidants, stabilizers)
Antioxidants inhibit the foaming of the resin foam, so it is desirable to use them in small amounts. In addition to antioxidants, light stabilizers, weathering agents and the like may optionally be included. By blending an antioxidant, it is possible to prevent oxidative deterioration of the base resin constituting the foam.

Antioxidants include phenolic antioxidants, phosphite antioxidants, blends of phenolic antioxidants and phosphite antioxidants. phenol-based antioxidants, hindered amine-based compounds, and the like. The above antioxidants have effects as stabilizers or weather resistance agents in addition to the effects as antioxidants. For example, in the present invention, specifically, Irganox 1010 manufactured by BASF Corporation is used as tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane.

The content of the antioxidant is preferably 0.05 to 1.0 parts by mass with respect to 100 parts by mass of the polyethylene resin. If the content of the antioxidant is high, the cross-linking of the base resin will be inhibited and the viscosity will decrease, resulting in an increase in the size of the cells, which in turn causes gas escape and a decrease in the expansion ratio, resulting in inhibition of expansion. be. Therefore, it is desirable not to add more than 1.0 part by mass of the antioxidant.

(Other additives)
The resin foam in the present invention may further contain other additives such as lubricants, pigments containing carbon and titanium oxide, dyes, plasticizers, fillers, antistatic agents, etc., as long as they do not impede foamability. may contain. For example, these other additives can be added in the range of 2 parts by mass or less. For example, by adding a predetermined amount of an inorganic pigment, it is possible to impart designability. Known and commercially available additives can be used for these additives.

(Method for producing polyethylene resin foam)
Here, a method for producing a polyethylene-based resin foam will be described in the case of using low-density polyethylene as the base resin. First, an organic decomposable foaming agent and a cross-linking agent were added to low-density polyethylene as a base resin, kneaded in a pressurized kneader, and pelletized to obtain pellets of an expandable resin composition. The pellets thus obtained are charged from the hopper of a short-screw extruder and extruded through a die of a predetermined width to obtain a base sheet for foaming of a predetermined thickness.

The resin foam is produced by extruding a base material sheet for foaming at 120 to 150° C., continuously expanding it to a predetermined magnification in a heating furnace at 200 to 230° C., and then passing it through rolls to obtain a foam. After adjusting the dimensions and surface properties of the pipe, it is cut to a predetermined width according to the diameter of the pipe to be wound.

The foaming ratio must be controlled in consideration of heat insulating properties, embossing properties, and cushioning properties. If the expansion ratio is too high, it will be difficult to stably and uniformly perform embossing after lamination of the nonwoven fabric. , there is a problem that the heat insulation is reduced. Therefore, the expansion ratio of the resin foam is desirably 20 to 40 times, and within this range there is no particular problem. There is no particular problem with cushioning properties as long as the expansion ratio is in the range of 20 to 40 times. In this example, the foam was expanded 30 times. For 30-fold expansion, 16 parts by mass of an organic decomposable foaming agent and 0.8 parts by mass of a cross-linking agent can be added to 100 parts by mass of polyethylene resin. That is, the contents of the foaming agent and the cross-linking agent can be appropriately adjusted according to the expansion ratio.

At this time, as the polyethylene resin, a mixed resin obtained by mixing LDPE and HDPE at a mass ratio of 4:6 may be used as the polyethylene resin. For LDPE, use F120N manufactured by Ube Maruzen Polyethylene Co., Ltd., for HDPE, use HD1300 manufactured by Japan Polyethylene Co., Ltd., for the foaming agent, trade name Vinihole AC#LQ manufactured by Eiwa Kasei Co., Ltd., for the cross-linking agent, Japan Yushi Co., Ltd. trade name Permil D was added in the above ratio.

In the present invention, the heat insulating material for preventing dripping of condensed water of the present invention can be obtained by joining a non-woven fabric to at least one surface of the polyethylene resin foam by fusion bonding. The nonwoven fabric to be placed on top will be described. Here, the bonding of the nonwoven fabric to the resin foam may be performed not by fusion but by adhesion.

(non-woven fabric)
First, to clarify the definition of non-woven fabric, JIS states that ``non-woven fabric is a sheet-like product in which fibers are laminated without being woven, and is a fiber sheet, web, or pad in which the fibers are oriented in one direction or randomly. entangled and/or fused and/or bonded between fibers, excluding paper, textiles, tufts and crimped felts.”

(Fiber used for nonwoven fabric)
The nonwoven fabric of the present invention does not exclude the use of natural material-based resins such as rayon-based resins and acetate-based resins as natural material-based fibers, but mainly the fiber diameter and porosity of the fibers constituting the non-woven fabric are set within a predetermined range. In order to control the three-dimensional structure of the nonwoven fabric, dew condensation is prevented by setting the mechanical properties based on the tensile modulus to a predetermined ratio. For this reason, since the fibers themselves do not need to have water absorbability, chemical material-based fibers are used for the fibers constituting the nonwoven fabric. Polyester-based fibers, polyethylene fibers, polypropylene fibers, acrylic fibers, and the like can be used as the chemical material-based fibers.

In the present invention, even if the nonwoven fabric itself is a fiber having no water absorbability, it is possible to provide the nonwoven fabric with the ability to prevent dripping of condensed water as long as it has a predetermined structure. Industrial definitions of these fibers are described as follows in Textile Terminology (Raw Material Section) Part 2: JIS for Chemical Fibers, JISLO204-2 (2001). In addition, in the present invention, the three-dimensional structure of the nonwoven fabric is complicated and does not have a regular structure, and it is difficult to directly and quantitatively specify the three-dimensional structure of the nonwoven fabric. Tensile modulus is used as an alternative parameter.

Polyester fiber is a fiber composed of a long-chain synthetic polymer containing 85% or more by mass of an ester unit of terephthalic acid and a dihydric alcohol. Polyethylene fiber is a polymer composed of saturated aliphatic hydrocarbons without substituents. Fibers made of long-chain synthetic polymers, polypropylene fibers are polymers composed of saturated aliphatic hydrocarbons with a side chain of a methyl group on one carbon atom per two, and have stereoregularity and other Fibers made of long-chain synthetic polymers without substituents, acrylic fibers, are fibers made of straight-chain synthetic polymers containing 85% or more by mass of repeating units of acrylonitrile groups.

Here, since polyester fibers, polyethylene fibers, and polypropylene fibers do not absorb water, even if the fiber surface absorbs water vapor, the fiber itself does not absorb water, so there is no change in fiber strength, and there is no decrease in strength due to water absorption. However, although the strength of acrylic fibers slightly decreases due to moisture absorption, the dry-wet strength ratio is 0.9 or more, and the decrease in strength is slight compared to rayon and vinylon, which are natural materials. There is no particular problem when acrylic fibers are used as mixed fibers with non-flexible fibers. In addition to polyethylene fibers, polypropylene fibers, polyester fibers, and acrylic fibers, fibers constituting the nonwoven fabric may contain a predetermined amount of natural fibers such as cellulose fibers, pulp, and rayon fibers. The content should be within 30% of the total weight of the fibers considering the decrease in strength due to moisture absorption of these fibers. Here, when using fibers such as cellulose fibers and pulp, it is desirable to use short fibers.

(Composition and structure of fibers of nonwoven fabric)
Here, a plurality of fibers can be used for the nonwoven fabric used in the present invention. For example, polyethylene fibers and PET fibers, polyethylene fibers, and polypropylene fibers can be used in combination. In this way, when polyethylene fibers, PET fibers, or polypropylene fibers are used in combination, a plurality of fibers are mixed at a predetermined ratio, and the number of fusion points at which fibers are fused together can be easily controlled. 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 a plurality of fibers or fibers with a core-sheath structure is that the fibers can be selectively fused together by utilizing the difference in the melting points of different resins.

As the non-woven fabric fibers, in addition to using a mixture of two kinds of fibers, a non-woven fabric using fibers having a core-sheath structure can be used. The advantage of using fibers with such a core-sheath structure in a nonwoven fabric is that when the fibers are fused to each other, for example, PET fibers or polypropylene fibers are used for the core and polyethylene fibers are used for the sheath. , it is possible to fuse the fibers together at a relatively low temperature of 120 to 140 ° C., making it possible to facilitate the production of nonwoven fabrics, and at the same time, the core is made of higher strength fibers than the sheath. By using it, the rigidity of the fibers used in the nonwoven fabric can be increased, which makes it possible to reduce the fiber diameter of the fibers constituting the nonwoven fabric by that amount, making it easier to control the porosity of the nonwoven fabric. Become.

As the non-woven fabric fibers, a plurality of fibers having different melting points are used, and the fibers having a low melting point are melted and used as a binder to form a non-woven fabric. Here, when PET fiber and polyethylene fiber are mixed and used in a predetermined ratio, the polyethylene fiber acts as a binder. For example, PET resin can be used as the main component fiber, and copolymer polyester (Co-PET) resin, polypropylene resin, polyethylene resin, or the like can be used as the low-melting-point fiber as the binder. With the above structure, the porosity of the nonwoven fabric, the strength of the nonwoven fabric, and the like can be easily controlled, so that, for example, a nonwoven fabric having a predetermined strength can be obtained even if the porosity is high.

Here, as the nonwoven fabric fiber of the present invention, a nonwoven fabric using a combination of fibers having a core-sheath structure having different melting points and other fibers can also be used. For example, by using higher-strength fibers in the core than in the sheath to increase the rigidity of the fibers used in the non-woven fabric, at the same time high-strength fibers or hollow fibers are used in other fibers to control the mixing ratio of both. With this, it becomes possible to improve the mechanical properties of the nonwoven fabric and to impart softness to the nonwoven fabric.

In addition, when long fibers are used as the nonwoven fabric fibers of the present invention, the fibers are easily oriented in the MD direction, which is the main direction in the production of the nonwoven fabric, and due to this, the mechanical properties in the direction are compared to the mechanical properties in the TD direction. However, by using short fibers, the effect of the orientation of the fibers in the MD direction can be alleviated, and the orientation in the TD direction can be improved. I can expect it. In addition, it is presumed that the same effect as that of short fibers can be obtained by using crosswise crosswise nonwoven fabrics and crosswise crosswise nonwoven fabrics.

As a nonwoven fabric that can reduce the influence of the orientation of fibers in the MD direction and the TD direction without using staple fibers, there is a crosswise nonwoven fabric. The warp-and-warp nonwoven fabric is a nonwoven fabric in which a warp web and a weft web are perpendicularly laminated and bonded. The warp and weft webs are cross-laminated in a laminating machine, and the warp webs are longitudinally stretched, and the weft webs are transversely stretched. In addition to the above, there is a weft and weft oblique nonwoven fabric in which a weft and weft nonwoven fabric is added to the weft and weft nonwoven fabric. In this way, by using a weft crossed nonwoven fabric or a weft and weft oblique nonwoven fabric, even if it is a nonwoven fabric using long fibers instead of short fibers, the influence of the orientation of the fibers can be reduced, so that the short fibers can be used. The same effect as in the case of nonwoven fabric can be obtained.

By using a nonwoven fabric that satisfies the structural characteristics of the heat insulating material for preventing dripping of condensed water of the present invention, such as fiber diameter, porosity (filling rate), and presence or absence of bent portions of fibers, the dripping prevention property of condensed water is improved. There is no need to use a resin with water absorption, and the thickness of the nonwoven fabric can be 1.0 mm or more, but the thickness of the nonwoven fabric is 1.0 mm or less, Anti-dripping properties and embossability, which will be described later, can be satisfied.

(Method for manufacturing nonwoven fabric)
Next, the manufacturing method of the nonwoven fabric will be confirmed. Generally, non-woven fabrics are formed by forming a film-like sheet called a thin film-like web composed only of fibers, and by bonding only the necessary portions of each fiber forming the formed web as necessary. be done.

There are various methods for forming a nonwoven fabric. For example, there are both a wet method and a dry method as methods for forming a web. In the wet method, fibers are made into a nonwoven fabric in the same manner as in the papermaking process. There are various methods for forming a web in the dry method, as will be described later, and any method may be used to form the web. When using, it is necessary to bend the fibers to form a three-dimensional structure of the nonwoven fabric.

Also, to obtain a nonwoven fabric from a web, it is necessary to bond the fibers forming the web in place. Here, the fiber bonding method of the web includes a chemical bond method such as an immersion method and a spray method, a thermal bond method, a spunbond method, a meltblown method, a meltplane method, an air lay method, a spunlace method (water exchange method), and a needle. There are various methods such as the punch method. Here, as a method for forming a nonwoven fabric using long fibers, the following chemical bond method, thermal bond method, spunbond method, melt blow method, melt plane method, etc. are used, and nonwoven fabrics using short fibers are used. As a forming method, a chemical bond method, a thermal bond method, an air lay method, a spunlace method, and a needle punch method can be used. A chemical bond method, a thermal bond method, an air lay method, a spunlace method, and the like can be used for both long fibers and short fibers.

To explain each method specifically, the chemical bond method is a method of partially bonding a web with an adhesive, and the thermal bond method mixes low-melting heat-fusible fibers and passes them through hot rolls. In this method, the fibers are bonded to each other by thermocompression bonding or by applying hot air to bond the heated portions of the fibers with the fibers that melt. The spunbond method is a method in which fibers are arranged directly with spinning and made into cloth by self-fusion heat. The meltblown method is a method in which fibers are arranged directly with spinning and ultrafine fibers are entangled. The melt-brain method is a method in which a resin is melted and high-temperature air is jetted from the periphery of a spinning nozzle to make fibers thinner and accumulate them in a sheet form.

The air lay method is a method of bonding pulp together with air and a binder to form a nonwoven fabric. Also, the spunlace method is a method of entangling fibers with a high-pressure water stream. The needle punch method is a method of manufacturing a nonwoven fabric by repeatedly piercing a web with a special needle that moves up and down at high speed and entangling fibers with projections formed on the needle.

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. The method is open-ended. In the range of the predetermined fiber diameter used in the present application, it has a predetermined porosity, and the nonwoven fabric has a crimp property such that the effective stress value at 5% elongation in the tensile test satisfies a predetermined value. Any method may be used as long as the nonwoven fabric can be used for the purpose of the present invention.

Here, when the nonwoven fabric used in the present invention is produced from short fibers, the chemical bond method, thermal bond method, air lay method, spunlace method, and needle punch method are often used. When using such a nonwoven fabric using short fibers, it can be expected that the difference in orientation between the MD direction and the TD direction of the fibers can be reduced compared to the case of using a nonwoven fabric using long fibers. . Therefore, there is a possibility that both the mechanical properties and differences in nonwoven fabrics can be reduced.

As a nonwoven fabric that can reduce the influence of the orientation of fibers in the MD direction and the TD direction without using staple fibers, there is a crosswise nonwoven fabric. The warp-and-warp nonwoven fabric is a nonwoven fabric in which a warp web and a weft web are perpendicularly laminated and bonded. The warp and weft webs are cross-laminated in a laminating machine, and the warp webs are longitudinally stretched, and the weft webs are transversely stretched. In addition to the above, there is a weft and weft oblique nonwoven fabric in which a weft and weft nonwoven fabric is added to the weft and weft nonwoven fabric. In this way, by using a weft crossed nonwoven fabric or a weft and weft oblique nonwoven fabric, even if it is a nonwoven fabric using long fibers instead of short fibers, the influence of the orientation of the fibers can be reduced, so that the short fibers can be used. The same effect as in the case of nonwoven fabric can be obtained.

(Method of laminating nonwoven fabric to polyethylene resin foam)
By placing a nonwoven fabric on one surface of the polyethylene resin foam and performing hot roll molding, the nonwoven fabric and the polyethylene resin foam can be fused. Alternatively, an adhesive is applied to one surface of the polyethylene-based resin foam, and in this state, the non-woven fabric is placed on the surface of the polyethylene-based resin foam and subjected to hot roll molding to form a non-woven fabric. It can be fixed to the surface of a polyethylene-based resin foam.

(Embossing method)
For example, a material in which a nonwoven fabric is fused to one surface of a foam is embossed by passing it through a pair of upper and lower embossing rolls while being heated to a predetermined temperature by an infrared heater. can be done.

When embossing, the surface of the material to be passed through the embossing roll is heated with an infrared heater to a predetermined temperature, for example, 120 to 150° C., and the embossing roll itself heats the roll-passing material such as nonwoven fabric to the roll surface. In consideration of wear, the roll surface temperature is kept at a predetermined temperature, for example, 20° C. by cooling. By heating the material and cooling the roll in this way, it is possible to prevent the nonwoven fabric bonded to the surface from being seized.

In addition, the uneven pattern used for embossing ^is not particularly limited as long as it ^can be shaped, and may be of any shape. Embossing is performed by forming a pattern of about 1.2 mm in the shape of a truncated square pyramid over the entire width of the product so that each side of the truncated square pyramid coincides with the MD direction and the TD direction.

At the time of embossing, the nonwoven fabric itself is heat-molded, so although the effect of deformation strain on the three-dimensional structure is recognized, the effect is not so large, and there are no differences in structural characteristics between test materials. maintained. However, compared to non-embossed products, the effect of embossing is disadvantageous in terms of preventing dripping of condensed water. It will be a severe test. If the embossed product does not cause dripping of condensed water in the dew condensation evaluation test, it means that the unprocessed product does not cause dripping of condensed water due to condensation.

(Measuring method)
In the examples below, since the heat insulating material of the present invention is composed of a resin foam and a non-woven fabric, various heat insulating materials with different compositions and structures of non-woven fabrics and foams are used before and after embossing. The presence or absence of dripping of condensed water and the embossability of the heat insulating material were evaluated by the dew condensation evaluation test of these heat insulating materials. Here, since the structure of the nonwoven fabric is considered to have a large effect on the dew condensation property and embossability, the parameters that determine the structure of the nonwoven fabric are fiber diameter, filling rate, porosity, and 5% elongation in a tensile test. In addition to determination of effective stress value and evaluation of water retentivity, structural observation of nonwoven fabric fibers by SEM and optical microscope observation of nonwoven fabric after water absorption were performed as necessary.

(Measurement evaluation method for nonwoven fabric)
As measurement evaluation methods for evaluating the structure of nonwoven fabrics, methods for measuring fiber diameter, thickness, porosity, and filling rate of nonwoven fabrics, methods for measuring effective tensile stress values by tensile tests, and methods for SEM observation and optical microscope observation of nonwoven fabrics. As a performance evaluation method related to the dew condensation property of the nonwoven fabric, the water retention amount was measured as an evaluation of the water retention. In addition to the performance evaluation test of the nonwoven fabric, the dew condensation property and embossing property evaluation test of the heat insulating material were also conducted. These methods will be described in detail one by one.

(Nonwoven fabric thickness)
The nonwoven fabrics used in the tests, thicknesses of 0.22 mm to 0.95 mm were used. The thickness of the nonwoven fabric used in the test was measured using a nonwoven fabric thickness measuring instrument (φ56.4 mm disc flat measuring tip) capable of measuring the same as the A method of the measuring method described in JIS general nonwoven fabric measuring method (JISL1913: 2010). It is measured based on the law.

(fiber diameter)
For the fiber diameter of the nonwoven fabric, 20 locations were arbitrarily selected from the SEM fiber image, and the average fiber diameter (number average) was calculated using image processing software. Here, the average fiber diameter of the nonwoven fabric used in the present invention is in the range of 10 μm to 30 μm, and the fibers of this range are usually used in many cases. The reason for this is that although it is possible to produce a nonwoven fabric with a fiber diameter of 10 μm or less, if the fiber diameter is 10 μm or less, the strength of the nonwoven fabric is insufficient, and the durability of the surface of the protective member during use is reduced. On the other hand, 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 within the range of 85 to 98%. Therefore, it is desirable that the average fiber diameter be in the range of 10 to 30 μm. In addition, in each test material of each example of the embodiment, the measured value of the fiber diameter of each test material is described as a fiber diameter for simplification, but the measured value of these fiber diameters is the average fiber diameter. means.

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

(Measurement of effective tensile stress value in tensile test)
It is difficult to evaluate the crimpability, which indicates the degree of entanglement or bending of fibers in a nonwoven fabric, the influence of the joints of fibers, etc. on individual fibers and convert them into macro parameters of the overall structure of the nonwoven fabric. Therefore, by evaluating the parameters related to the elongation value and stress in the tensile test for each nonwoven fabric as an alternative parameter for evaluating the three-dimensional structure of the nonwoven fabric fiber, as an evaluation parameter associated with the porosity to ensure the water retention amount, The value obtained by dividing the stress value at 5% elongation in the tensile test by the filling rate, that is, the value normalized by the filling rate was measured and evaluated for the effective tensile stress value at 5% elongation.

According to this test, the behavior of elongation value and stress change in the tensile test has an effect not only on water retention but also on embossability. These behaviors were confirmed by a tensile test because it is considered that the better is desirable. Furthermore, considering the winding strain on the refrigerant pipe, in the case of the TD direction, in addition to the embossing distortion, the winding strain on the refrigerant pipe is added, so the elongation value in the TD direction is larger than the elongation value in the MD direction. , it was considered desirable that the stress increase in the tensile test is small.

Here, the effective stress value was measured only in the MD direction because the TD direction is a direction perpendicular to the WEB direction of the nonwoven fabric. It was found that it was difficult to measure the strain stably, and that the rise of stress in all nonwoven fabrics was lower than that in the MD direction. Therefore, it is difficult to obtain the effective stress value at 5% elongation in the TD direction, and it was determined that the evaluation parameters for the tensile behavior in the MD direction affect the water retention and drip prevention properties of the nonwoven fabric. Therefore, we decided to preferentially obtain the effective stress value at 5% elongation in the MD direction. As will be described later, in Example 3 of the first embodiment, a short fiber nonwoven fabric and a weft and weft oblique nonwoven fabric with improved effective tensile stress in the TD direction were produced. In addition to the effective tensile stress value, the effective tensile stress in the TD direction was also determined.

In addition, the reason why the effective stress value of the nonwoven fabric was determined as the effective stress value at 5% elongation is that from the results of the preliminary test, the stress value at 2% elongation is a measurement of a minute deformation area, so the uniformity of the nonwoven fabric material In addition, the accuracy of the measured strain amount varies, and the accuracy cannot be guaranteed, and the effective tensile stress level is small, making it difficult to determine the difference between each material. On the other hand, at 10% elongation, in addition to the difference in the three-dimensional structure of the fibers in the nonwoven fabric, there are also macrostructural changes due to state changes such as engagement, friction, and fusion between the fibers of each nonwoven fabric, and secondary changes due to the progress of tensile deformation. This is because there is a possibility that deformation will be applied to the stress level area where the effect caused by the change in the state of the nonwoven fabric appears, and it may not be possible to correctly evaluate the three-dimensional structure as the initial state of the nonwoven fabric. % is considered to be an appropriate parameter to indirectly express the structure of the nonwoven fabric.

A JIS K6251 (2017) No. 1 dumbbell-shaped test piece was punched out from each nonwoven fabric in the MD direction, the sample was held at a distance between chucks of 80 mm, a distance between gauge lines was 40 mm, and a tensile test was performed at 10 mm / min. The effective tensile stress at the time when the strain amount between is 5% is measured, this value is divided by the fiber filling rate of the nonwoven fabric, and the normalized effective stress value at 5% elongation is the effective tensile stress value at 5% elongation. expressed as In consideration of variations in the effective tensile stress value, each test was performed three times, and the average value was defined as the effective tensile stress value of each material.

(SEM observation and optical microscope observation of nonwoven fabric)
In order to confirm the degree of bending and the entanglement structure of the fibers that make up the nonwoven fabric, a scanning electron microscope (SEM) was used at an acceleration voltage of 20 KV and at a magnification of 100 times. In addition, representative examples of nonwoven fabrics that do not have the effect of preventing dripping of condensed water were observed. In addition, in order to confirm the water retention state of the nonwoven fabric that has the effect of preventing dripping of condensed water, the same material as that used for SEM observation was examined with an optical microscope at a magnification of 100 times, which is the same as in the case of SEM observation. Optical microscope observation was performed in a water-retained state.

Here, the water absorption operation of the test piece for which the water retention state of the nonwoven fabric was confirmed with an optical microscope was performed according to the following procedure. First, a nonwoven fabric having a size of 30 mm×30 mm was cut out, and this was immersed in a beaker containing water for 2 minutes or longer to sufficiently retain water. After that, the sample was lifted with tweezers, waited until the water droplets were completely dropped, and furthermore, the sample was brought into contact with the edge of the beaker and held for 30 seconds. This was placed on the sample stage of the microscope and measured with an optical microscope.

(water retention capacity)
A nonwoven fabric having a certain area is cut out from each nonwoven fabric used in the test and weighed. After that, the non-woven fabric is immersed in tap water to absorb enough water, and then lifted for 30 seconds or more to prevent water droplets from falling, and then weighed again. The water retention weight (g/m ² ) is obtained by dividing the water retention weight by the area to calculate the water retention capacity per unit area (m ² ). Since the nonwoven fabrics used in the test have different nonwoven fabric thicknesses, the water retention capacity of each nonwoven fabric was compared in terms of the water retention capacity at a predetermined nonwoven fabric thickness of 1 mm. The water retention amount on the left side of Tables 1 to 3 is the water retention amount as a measured value, and the water retention amount on the right side indicates the converted water retention amount g/(m.mm) at a nonwoven fabric thickness of 1 mm.

(Drip prevention evaluation test for condensed water)
FIG. 1 is a diagram showing the state of a dew condensation confirmation test using a constant temperature and humidity chamber. As shown in FIG. 1(a), the dew condensation test was carried out by placing the non-woven fabric fused to the surface of the resin foam on a stainless steel pipe as a refrigerant pipe, with the surface of each heat insulating material for preventing dripping of condensed water facing outward. It is arranged in a constant temperature and humidity chamber 1 by winding four pieces each. Here, in the test, a refrigerant winding (stainless steel pipe) 2 having dimensions (outer diameter 49φ x inner diameter 45φ x wall thickness 2 mm) was used as a refrigerant pipe, and one side of the foam with a foaming ratio of 30 times and a thickness of 10 mm was used. Various heat insulating materials 3 having non-woven fabrics fused to their surfaces were prepared, cut into lengths of 150 mm, and wrapped around the entire circumference of the refrigerant pipe 2 . Here, for the heat insulating material 3, both the embossed material in which the surface of the nonwoven fabric was embossed and the non-embossed material in which no embossing was performed were used for each test material. Hereinafter, in the present invention, the constant temperature and humidity bath may be simply referred to as a constant temperature bath.

During the test, after the above preparations were completed, the constant temperature bath was held at 23° C. and humidity of 50% RH for 3 hours, and then a 5° C. coolant was flowed through the stainless steel tube 2 to create an atmosphere with a test temperature of 35° C. and humidity of 90% RH. After that, the temperature was raised in 30 minutes, and then the heat insulating material for preventing dripping of dew condensation water was held for 12 hours. The presence or absence was evaluated. During the test, the outside temperature of the refrigerant pipe was checked at point A, the non-woven fabric surface temperature at point B, and the ambient temperature in the constant temperature bath at point C. The measurement temperature at points A, B, and C was controlled to ±0.5° C. with respect to the set temperature.

Further, the temperature in the constant temperature bath was confirmed by measuring the temperature by placing a thermocouple at the position shown in the figure. Thermocouples are used to measure the ambient temperature in the constant temperature bath, the surface temperature of the embossed nonwoven fabric, and the interfacial temperature of the stainless steel pipe and polyethylene resin foam at multiple points, and the measured temperature at each of the same measurement positions. was set so that the error was within ±0.5°C. In addition, in the test, the number of test materials to be tested is arranged in a constant temperature chamber of 4, and the presence or absence of dripping of condensed water is confirmed for each test material of Examples 1 to 3, which will be described later. The test was repeated according to the number of test materials. Therefore, the tray for measuring the presence or absence of dripping of condensed water was arranged for each test material so as to correspond to the position of each test material. When the number of test pieces was less than 4, the test pieces not to be measured were placed in the constant temperature bath and the test conditions were always the same. As a result of the test, the sample with no dripping of condensed water was evaluated as "◯", and the sample with dripping of condensed water was evaluated as "x".

FIG. 1(b) is a cross-sectional view of the heat insulating material 3 surrounding the refrigerant pipe 2 in the dew condensation evaluation test when embossing is performed. The heat insulating material 3 wrapped around the outer periphery of the refrigerant pipe 2 is composed of a resin foam 7 and a nonwoven fabric 8. The nonwoven fabric 8 is arranged on the outermost surface of the resin foam 7, and the nonwoven fabric 6 is embossed to form an embossed portion. Asperities are formed by 9 . As shown in Table 1, the nonwoven fabric used in the test has a different thickness depending on the nonwoven fabric.
Further, FIG. 1(b) is a cross-sectional view showing a laminated structure in which a resin foam is arranged around the outer periphery of a stainless steel pipe serving as a refrigerant pipe during testing, and a non-woven fabric is arranged on the outermost periphery. Concavities and convexities are formed on the surface of the nonwoven fabric by embossing.

(Embossability)
A material in which a non-woven fabric is fused to one surface of a polyethylene-based resin foam is heated to a predetermined temperature by an infrared heater, and is passed through a pair of upper and lower embossing rolls to form a bottom surface of about 4.5 mm. A square frustum pattern of 0 mm ² × top surface 2.5 mm ² × height of about 1.2 mm is applied over the entire product width so that each side of the pattern coincides with each of the MD and TD directions. Embossability was evaluated by performing embossing to shape.

Specifically, the embossability was evaluated by 10 pieces each in the MD direction and the TD direction. Judgment is based on whether the above target shape can be stably secured, and if the target shape is obtained in the evaluated embossed part, ◯, and if at least one surface is crushed, etc., it is the target. When the shape of the nonwoven fabric could not be obtained or when the fibers forming the nonwoven fabric were damaged, it was evaluated as x.

As a first embodiment of the present invention, Tables 1 to 3 show the results of an evaluation test for preventing dripping of condensed water and the evaluation results of embossing properties of various heat insulating materials. As the second embodiment, the results of applying the heat insulating material of the present invention to various piping structures are shown, and as the third embodiment, the results of applying the heat insulating material of the present invention to building materials are shown. As examples of application to building structures, a structure for preventing dripping of condensed water on inorganic building materials, a structure for preventing dripping of condensed water on ducts, and a structure for preventing dripping of condensed water on folded plate roofs will be described in sequence. Here, the duct relates to an air-conditioning duct, but since the duct is a relatively large member formed in a building structure, in the present invention, the structure for preventing dripping of condensed water from the duct is a building structure. It was decided to include it in the embodiment of the case of application to the body. In addition, in each fiber constituting the nonwoven fabric of the test material of Examples 1 to 3 (Tables 1 to 3) of the first embodiment, the fiber of the core-sheath structure is described in parentheses, and the left side in the parentheses is The core part and the right side represents the sheath part. Generally, the fibers forming the sheath have a lower melting point than the fibers forming the core.

(First Embodiment: Example 1)
Here, for all test materials, a foam obtained by foaming LDPE with an expansion ratio of 30 times and a thickness of 10 mm was used as a resin foam. Heat insulating materials of test materials 1 to 5 were obtained by fusing onto the foam. Here, the nonwoven fabric was fused to the surface of the foam by hot roll molding under the above conditions. Various tests to determine the structure of the nonwoven fabric, an evaluation test of the dew condensation property of the heat insulating material, and an embossing property test were conducted to evaluate the influence of the nonwoven fabric structure on dew condensation and embossability. For reference, Table 1 also shows where the nonwoven fabrics used in the test were obtained.

Here, in addition to test materials 1 to 5, a heat insulating material as a conventional material in which dew condensation occurs by fusing a polyethylene film on the surface of a polyethylene resin foam was also added to the test. Here, since the conventional material has a film thickness of 80 μm and has no voids, it can be said that the material has a filling rate of 100% and a porosity of 0%.

Here, the test material 1 is a PET fiber with a fiber diameter of 17.3 μm, a filling rate of 16.2%, and a porosity of 83.8%, and has little fiber bending. The diameter of the fiber is 17.1 μm, the porosity is 97.8%, and the fiber has a lot of bending. At most, test material 4 is an acrylic/(PET/PE) fiber with a fiber diameter of 11.7 μm, a porosity of 91.2%, and a fiber with many bends, and test material 5 is a PET/PE fiber, The fiber has a fiber diameter of 18.9 µm, a porosity of 97.6%, and a large amount of bending. Here, the nonwoven fabric 1 of the test material 1 has a porosity that does not exceed 85% and has little bending, but the non-shrinkable fabrics 2 to 5 of the test materials 2 to 5 have a fiber diameter in the range of 10 to 30 μm. A relatively large number of bending portions of the fibers were observed, satisfying the porosity range of 85 to 98%.

Here, test materials 1 and 2 are nonwoven fabrics made of ordinary PET fiber alone, and test material 3 is, specifically, a PP/PE fiber with a core-sheath structure (PP is the core material and the outside is PE). It is a nonwoven fabric made of a composite fiber of PET fiber and a core-sheath structure fiber), and test material 4 is a nonwoven fabric made of a core-sheath structure fiber in which the outer circumference of the PET fiber is coated with PE fiber and acrylic fiber. It is a nonwoven fabric. The test material 5 is a nonwoven fabric using mixed fibers of PE fibers and PET fibers.

(Test results)
Table 1 shows the test results of Example 1 in the first embodiment. According to the test results in Table 1, the results of the anti-dripping property evaluation test for condensed water after embossing showed that the heat insulating materials of test materials 2 to 5 showed good results with no dripping of condensed water. Condensed water dripped on the test material 1 and the conventional material. Here, when looking at the relationship between the presence or absence of dripping of condensed water on the test material and the structure of the nonwoven fabric, the average fiber diameter is in the range of 10 to 30 μm, and the porosity is 85 to 98% (filling rate is 2 to 15%). It was confirmed that dripping of condensed water does not occur in a nonwoven fabric with an effective tensile stress of 25 MPa or less, which is the value obtained by dividing the apparent tensile stress in the same direction by the filling ratio when the value of tensile elongation in the MD direction in the tensile test is 5%. was done. Specifically, the effective tensile stress values of test materials 2 to 5 are in the range of 7.2-17.2 MPa. As a result of SEM observation, which will be described later, it was confirmed that these non-woven fabrics free from dripping of condensed water had many bends in the fibers and high crimpability of the fibers. In addition, the nonwoven fabric satisfies the water retention capacity of 500 g/m ² or more converted per 1 mm of apparent thickness of the nonwoven fabric to prevent dew condensation. The results of the dripping test of condensed water before embossing were the same as those before embossing, and embossing did not affect the dripping of condensed water.

On the other hand, Test Material 1, which is a nonwoven fabric with dew condensation, has a fiber diameter that satisfies the above range of 10 to 30 μm, but has a porosity of less than 85% and a filling rate of more than 15%. The effective tensile stress, which is the apparent stress in the same direction at 5% divided by the filling fraction, was well above 38.5 MPa and 25 MPa. Furthermore, the number of bent portions of the fibers constituting the nonwoven fabric was small, and the crimpability of the nonwoven fabric was low. The amount of retained water that could not prevent dripping of the nonwoven fabric did not satisfy 500 g/m ² of retained water per 1 mm of apparent thickness of the nonwoven fabric. As described above, it was confirmed that a nonwoven fabric having a high porosity and a small effective tensile stress value at a predetermined strain amount of 5% elongation is superior in terms of the occurrence of dew condensation. In addition, although the fibers used in the test were chemical fiber-based materials that do not absorb water, the ability of the nonwoven fabric of the present invention to prevent dripping of condensed water basically does not depend on the type of fiber. It was thought that it would be established only by

According to the results of test materials 1 to 5, even in the case of test materials 4 and 5, which are heat insulating materials using fibers with a core-sheath structure, the fibers forming the nonwoven fabric are either a nonwoven fabric made of a single fiber or a core. Regardless of whether a fiber with a sheath structure or two types of composite fibers of different materials are used, water retention and prevention of dripping of condensed water are determined by the void ratio of the fiber and the tensile stress at 5% elongation as the filling ratio. It was found that there is a correlation with the effective tensile stress obtained by dividing.

Here, the reason why such a result was obtained is that when the nonwoven fabric is cooled below the dew point, in the case of a nonwoven fabric with a high porosity, the fibers are often bent and crimped, so that the porosity When the three-dimensional spatial network made up of the fibers of the non-woven fabric with high moisture content is cooled to a temperature below the dew point, a large number of independent water films are formed to connect the fibers, resulting in a large amount of moisture in the non-woven fabric. Although water is retained, conversely, if the nonwoven fabric has a low porosity and a high filling rate, the high filling rate reduces the space where the water film is formed. The state of formation of the water film is based on the fact confirmed with an optical microscope.

Regarding embossability, test material 1, which has a high filling rate, has many overlapping fibers, and the nonwoven fabric fibers may break, and the shape of the embossed part may become unstable due to the elastic recovery of the fibers. Decreased. In addition, test materials 2 to 5 have an average fiber diameter of 10 to 30 μm and a high porosity of 85 to 98%. There was no deterioration in embossability.

As a result, a nonwoven fabric structure with an average fiber diameter of 10 to 30 μm and a high porosity of 85 to 98% has a nonwoven fabric thickness of 1.0 mm or less and a tensile elongation value in the MD direction in a tensile test of 5% in the same direction. If the effective tensile stress, which is the value obtained by dividing the apparent tensile stress by the filling rate, is 25 MPa or less and 1 MPa or more, regardless of the presence or absence of embossing, the water retentivity of the heat insulating material for preventing dripping of condensed water can be ensured.

(First Embodiment: Example 2)
It was thought that the composition of the foamed resin had almost no effect on the ability to prevent dripping of condensed water, but in Example 2, an experiment was conducted to confirm the influence of the composition of the polyethylene-based resin foam on the condensation and embossability. was carried out using combinations of resin compositions and nonwoven fabrics as shown in Table 2. In Example 2, the composition of the polyethylene-based resin foam was changed to LDPE, and various changes were made to HDPE, a mixed resin of LDPE and HDPE, or various polyethylene-based foams such as EVA resin, and heat resistance was improved as necessary. For this reason, resin foams containing carbon, titanium oxide, or a flame retardant to improve flame resistance are prepared, and these resin foams are used as nonwoven fabrics 2 or 4 that are excellent in preventing dripping of condensed water. were prepared as test materials. As in Example 1, the foams used for these heat insulating materials had an expansion ratio of 30 and a foam thickness of 10 mm. The blending amounts of the foaming agent and the cross-linking agent at this time were appropriately adjusted within the above ranges.

The heat insulating material of the test material 6 is a resin foam of HDPE, the test material 7 is a mixed resin mixed with LDPE and HDPE at 6:4, and the heat insulating material of the test materials 8 to 11 is the LDPE and HDPE mixed resin. It uses foam to which various additives are added. Specifically, the heat insulating material of the test material 8 is obtained by adding 0.5 parts by mass of carbon to the mixed resin, and the test material 9 is obtained by adding 2.0 parts by mass of titanium oxide. 1.0 parts by mass of antimony trioxide, 4.0 parts by mass of a brominated flame retardant, and 20 parts by mass of magnesium hydroxide were added to the test material 11 to use a resin foam. The heat insulating material of test material 12 is EVA with 80 parts by mass of magnesium hydroxide, and the heat insulating material of test material 13 is a resin foam obtained by adding 50 parts of aluminum hydroxide to EVA. Here, nonwoven fabric 2 using PET fiber is used as the heat insulating material for test materials 6 to 11, and nonwoven fabric 4 using acrylic/(PET/PE) fiber is used for test materials 12 and 13. Using.

(Test results)
Table 2 shows the test results of Example 2. From the test results in Table 2, the thermal insulation materials from test materials 6 to 13 were not affected by the composition of the foam, and the condensation water dripping did not occur. Also, the embossability was good. Therefore, in any of the heat insulating materials of Example 2, the non-woven fabric fused to the surface of the polyethylene resin foam has the predetermined fiber diameter of 10 to 30 μm and the porosity of 85 to 85, which were confirmed in Example 1. If a nonwoven fabric is used that satisfies 98% and the stress normalized by the filling rate at 5% elongation satisfies 25 MPa or less, the ability to prevent dripping of condensed water will be satisfied regardless of the resin composition of the foam. In addition, at this time, the thickness of the non-woven fabric used for the heat insulating material is 1 mm or less, and the water retention amount per 1 mm of the non-woven fabric thickness is 500 g/(m.mm). As in Example 1, there were no problems.

(First Embodiment: Example 3)
Table 3 shows that the effective tensile stress, which is the value obtained by dividing the apparent stress in the same direction when the value of tensile elongation in the MD direction in the tensile test in the MD direction is 5% by the filling rate, satisfies 25 MPa or less and 1 MPa or more. The effective tensile stress, which is the value obtained by dividing the apparent stress in the same direction when the value of tensile elongation in the TD direction in a tensile test is 5% by the filling rate, is 25 MPa or less and 1 MPa or more. A test result is shown. The purpose of this test is to ensure that the effective tensile stress, which is the value obtained by dividing the apparent stress by the filling rate, satisfies a predetermined value of 25 MPa or less and 1 MPa or more, regardless of the direction of the tensile test. It is to confirm the difference in the drip prevention properties of condensed water. For reference, Table 3 also lists the suppliers of the nonwoven fabrics used in the tests.

Table 3 shows the test results of test materials 14-19. 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 weft and diagonal oblique long fibers. The test material 14 is a nonwoven fabric made of acrylic/(PET/PE) fibers, having a fiber diameter of 11.7 μm, a porosity of 91.2%, and a large amount of fiber bending. The test material 15 is a non-woven fabric made of PET/PE fibers with a fiber diameter of 18.9 μm and a porosity of 97.6%, and with many fiber bends.

(Test results)
The test material 14 is a non-woven fabric made of acrylic fibers and core-sheath structured hollow PET fibers coated with PE fibers. The test material 15 is a nonwoven fabric using mixed fibers of PE fibers and PET fibers. Here, the non-shrinkable fabrics of the test materials 14 and 15 have a fiber diameter in the range of 10 to 30 μm and a porosity in the range of 85 to 98%, and relatively many bent portions of the fiber are observed. .

The test material 14 is a nonwoven fabric composed of long fibers of PET/PE fibers and acrylic fibers. It is the same material as test material 4. In the test material 14, in addition to the case of the test material 4, the test value of the effective tensile stress in the TD direction is added. The effective tensile stress, which is the value obtained by dividing the apparent stress in the same direction when the value of tensile elongation in the MD direction and TD direction in the tensile test of the test material 14 is 5% by the filling rate, is 11.5 and 0.91 MPa, respectively. Since the fiber diameter is 11.7 μm and the fiber porosity is 91.2%, both the fiber diameter, the porosity and the effective tensile stress in the MD direction are the effective tensile stress in the same direction at a tensile elongation value of 5%. satisfies 25 MPa or less and 1 MPa or more, but the effective tensile stress in the TD direction at a tensile elongation value of 5% does not satisfy the above range. In this case, the water retention amount per 1 mm of the nonwoven fabric was 700 g/m ² , no dripping of condensed water was observed before and after embossing, and the embossability was good.

The test material 15 is a non-woven fabric composed of long fibers having a core-sheath structure of PET/PE fibers, and is the same material as the test material 5 in Table 1. In the test material 15, in addition to the case of the test material 5, the test value of the effective tensile stress in the TD direction is added. The effective tensile stress, which is the value obtained by dividing the apparent stress in the same direction when the value of tensile elongation in the MD direction and TD direction in the tensile test of the test material 15 is 5% by the filling rate, is 17.2 and 0.97 MPa, respectively. Since the fiber diameter is 18.9 μm and the fiber porosity is 97.6%, the fiber diameter and porosity satisfy the ranges of the present invention, and both the effective tensile stress in the MD direction are within the ranges of the present invention. The effective tensile stress in the same direction at a tensile elongation value of 5% satisfies 25 MPa or less and 1 MPa or more, but the effective tensile stress in the same direction at a tensile elongation value of 5% in the TD direction does not satisfy the above range. In this case, the water retention amount per 1 mm of the nonwoven fabric was 1,383 g/m ² , no dripping of condensed water before and after embossing, and embossability was good.

The test material 16 is a nonwoven fabric made of long fibers of PET/PE fibers. In the tensile test of this test material 16, the effective tensile stress, which is the value obtained by dividing the apparent stress in the same direction when the value of tensile elongation in the MD direction and TD direction is 5% by the filling ratio, is 15.30 and 2.10 MPa, respectively. , the fiber diameter is 17.0 μm and the fiber porosity is 95.6%. The effective tensile stress in the same direction at a modulus of 85 to 98% and a tensile elongation value of 5% satisfies 25 MPa or less and 1 MPa or more in both MD and TD directions. In this case, the water retention amount per 1 m of the nonwoven fabric was 1,303 g/m ² , no dripping of condensed water was observed before and after embossing, and the embossability was good.

The test material 17 is a non-woven fabric made of short fibers having a core-sheath structure of PET/PE fibers. In the tensile test of this test material 17, the effective tensile stress, which is the value obtained by dividing the apparent stress in the same direction when the value of tensile elongation in the MD direction and TD direction is 5% by the filling rate, is 16.6 and 12.9 MPa, respectively. , the fiber diameter is 20 μm and the fiber porosity is 97.2%. The effective tensile stress in the same direction at 85 to 98% and the tensile elongation value of 5% satisfies 25 MPa or less and 1 MPa or more in both MD and TD directions. In this case, the water retention amount per 1 m of the nonwoven fabric was 937 g/m ² , no dripping of condensed water was observed before and after embossing, and the embossability was good.

The test material 18 is a nonwoven fabric made of short fibers of composite fibers of PET/PE fibers and pulp. The effective tensile stress, which is the value obtained by dividing the apparent stress in the MD direction and the TD direction tensile elongation value of 5% in the tensile test of this test material 18 by the filling ratio, was 3.50 and 3.30 MPa, respectively. , the fiber diameter is 18.3 μm and the fiber porosity is 91.1%. The effective tensile stress in the same direction at a modulus of 85 to 98% and a tensile elongation value of 5% satisfies 25 MPa or less and 1 MPa or more in both MD and TD directions. In this case, the water retention amount per 1 m of the nonwoven fabric was 1247 g/m ² , no dripping of condensed water was observed before and after embossing, and the embossability was good.

The test material 19 is a nonwoven fabric made of long fibers having a diagonal structure of PET/PE fibers. In the tensile test of this test material 19, the effective tensile stress, which is the value obtained by dividing the apparent stress in the same direction when the value of tensile elongation in the MD direction and TD direction is 5% by the filling ratio, is 8.89 and 4.41 MPa, respectively. , the fiber diameter is 18.0 μm and the fiber porosity is 94.4%. The effective tensile stress in the same direction at a modulus of 85 to 98% and a tensile elongation value of 5% satisfies 25 MPa or less and 1 MPa or more in both MD and TD directions. In this case, the water retention amount per 1 m of the nonwoven fabric was 925 g/m ² , no dripping of condensed water occurred before and after embossing, and embossability was good.

Here, the ratio of the effective tensile stress in the TD direction, which is the value obtained by dividing the apparent stress at the value of 5% tensile elongation of the test materials 14 and 15 by the filling ratio, to the effective tensile stress in the MD direction is 0.08,0 The anisotropy is large at .06, and the effective tensile stress in the TD direction of these materials is less than 1 MPa, whereas the effective tensile stress in the TD direction of test materials 16 to 19 is 0.14 to 0.94, the difference between the effective tensile stress in the TD direction and the MD direction is small, and the effective tensile stress in any TD direction exceeds 2 MPa.

The vertical structure and oblique structure in Table 3 show the result of whether or not dripping of condensed water occurs when the heat insulating material of the present invention is applied to pipes and structures of vertical structure and oblique structure. When the test material 15 was used, the effective tensile stress in the TD direction was less than 1 MPa, and in the case of a normal construction method in which the MD direction was aligned with the vertical direction, dripping of condensed water occurred.・The evaluation result of the condensed water in the oblique structure is "x". On the other hand, when test materials 16-19 were used, the effective tensile stress in both the MD and TD directions exceeded 1 MPa. Also, dripping of condensed water does not occur, and the evaluation result of dew condensation prevention of vertical structure and oblique structure is "○". Also, even if the test materials 14 and 15 are heat insulating materials, if the MD direction is not the vertical direction but is the horizontal direction, the effective tensile stress in the MD and TD directions exceeds 1 MPa. Since the same effect is obtained, dripping of condensed water does not occur.

As described above, as a nonwoven fabric structure with an average fiber diameter of 10 to 30 μm and a high porosity of 85 to 98%, the thickness of the nonwoven fabric is 1.0 mm or less, and the effective tensile stress in the MD direction in the tensile test is 25 MPa or less and 1 MPa or more. 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 and long fibers having an oblique structure are used. It was confirmed that a heat insulating material for preventing dripping of condensed water using such a nonwoven fabric can be obtained.

(Second Embodiment: Application of Heat Insulating Material of the Present Invention to Refrigerant Piping and Hot Water Supply Piping Structure)
Next, various piping structures to which the heat insulating material of the present invention is applied will be described as a second embodiment. As the piping structure, the following five types of piping structures are described. A piping structure in which the heat insulating material of the present invention is wrapped around the outer periphery of the pipe, a glasses-type piping structure in which two pipes with the heat insulating material wrapped around the outer periphery of the pipe are opposed to each other and the opposing portions are heat-sealed, and the existing refrigerant pipe A cylindrical piping structure surrounded by the heat insulating material of the present invention, a cylindrical piping structure surrounding an existing hot water supply pipe and its protective pipe with the heat insulating material of the present invention, and a piping structure in which the protective member of the present invention is applied to a vertical pipe. be.

(Second embodiment: Example 1)
(Piping structure in which the heat insulating material of the present invention is wrapped around the outer periphery of the refrigerant pipe)
FIG. 2(a) shows a perspective view of a piping structure in which a heat insulating material 3 for preventing dripping of condensed water is wrapped around the outer periphery of the refrigerant pipe 2 to cover the pipe. , The heat insulating material 3 in which the nonwoven fabric 8 after embossing and the polyethylene resin foam 7 are fused is placed so that the embossed part 9 of the nonwoven fabric faces the outer peripheral side and the resin foam surface is in contact with the pipe. It is a pipe wrapped around the outer circumference of the pipe. The heat insulating materials 3 wound around the outer periphery of the refrigerant pipe 2 face each other at the heat-sealed portion 11, and the opposing surfaces are fixed by heat-sealing or adhesion. FIG. 2(b) shows a cross-sectional view cut at a predetermined position including a straight line XX that crosses the pipe shown in FIG. 2(a) at right angles. The reason why the embossed part 9 is arranged so that the embossed part 9 faces the outer circumference of the heat insulating material 3 is that the outer circumference part is deformed according to the difference in circumference between the inner circumference and the outer circumference of the nonwoven fabric covering the refrigerant pipe 2. This is to make it easier.

(Second embodiment: Example 2)
(Spectacles-type piping structure in which refrigerant pipes coated with the heat insulating material of the present invention are opposed to each other and integrated)
FIG. 3(a) shows a spectacles-type piping structure 10 in which pipes coated with a heat insulating material 3 for preventing dripping of condensed water are opposed to each other and integrated with each other. In the piping structures 10a and 10b, the heat insulators 3 wound around the outer periphery of the refrigerant pipe 2 face each other at the heat-sealed portion 11, and the facing surfaces are fixed by heat-sealing or adhesion. FIG. 3(b) shows a cross-sectional view of the piping structure cut at a predetermined position including a straight line AA that crosses the two pipes shown in FIG. 3(a) at right angles. Temperature coolant flows. The reason why the embossed portion 9 is arranged so that the embossed portion 9 faces the outer periphery of the heat insulating material 3 is to facilitate deformation of the outer peripheral portion of the nonwoven fabric covering the refrigerant pipe 2 .

The heat insulating material of the present invention is wrapped around the outer periphery of the refrigerant pipe of the heat exchanger and formed into a cylindrical shape. Partially heated and melted to a predetermined temperature above the melting point of the non-woven fabric using ultrasonic waves, lasers, etc., and immediately after that, the parts are heat-sealed or thermo-compressed to form a pair of tubular pipe structures having a spectacle-shaped cross section. Obtainable.

In addition, the pipe shown in FIG. 3(a) is formed by placing both ends of the heat insulating material of the pipe wound with the heat insulating material shown in FIG. Thus, a spectacles-shaped piping structure can be obtained in which a heat insulating material, which is a non-woven fabric adhered to the surface of the resin foam by heat-sealing, is wrapped around the outer peripheral portion of the piping. At this time, both ends of the heat insulating material wound around the pipe can be fixed by bonding with double-faced tape or the like, in addition to heat sealing as described above.

Here, the spectacles-shaped pipe with a small pipe diameter is the refrigerant pipe for liquid, and the refrigerant pipe with a large pipe diameter is the gas 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 piping of the heat exchanger so that the embossed surface of the nonwoven fabric is arranged on the outer surface. By obtaining such a piping structure, the dew condensation that occurs in the conventional spectacle-shaped piping structure in which a heat insulating material in which a resin film such as polyethylene is attached to the surface of the polyethylene resin foam is wrapped around the piping, can be eliminated by the present invention. By using a glasses-type piping structure, it is possible to prevent dripping of condensed water.

(Second embodiment: Example 3)
(Cylindrical piping structure in which the existing refrigerant piping is surrounded by the heat insulating material of the present invention)
FIG. 4 shows a tubular refrigerant pipe structure 16 in which a plurality of refrigerant pipes, drain pipes and wiring are surrounded by the heat insulating material of the present invention. This pipe structure will be described. As a typical example of this piping, as a general heat exchanger piping, an air conditioner refrigerant piping 2 (two pieces), a drain pipe 12, a wiring 13, etc. are set, and the heat exchanger refrigerant piping 2, The drain pipe 12 and the wiring 13 are combined, and the whole of these pipes and wiring is surrounded by a cylindrical heat insulating material 14 with the nonwoven fabric 25 forming surface facing the outer peripheral surface, and used to connect the indoor unit and the outdoor unit of the heat exchanger. can do. At this time, both ends of the heat insulating material 3 surrounding the combined piping and wiring can be fixed by heat sealing, bonding with double-sided tape, or the like.

Here, in the case of conventional pipes, a resin foam sheet in which a resin film is bonded to the surface of each pipe as a heat insulating material covers the outer peripheral portion of each pipe. It is not a heat insulating material that has the effect of preventing dripping of condensed water by fusing a nonwoven fabric that satisfies the predetermined fiber diameter, filling rate, and tensile modulus as mechanical properties on the surface of the resin foam, so the heat insulating effect of the foam is Although it exists, even if the outer periphery of a set of pipes of a plurality of existing heat exchangers and a set of drain pipes and wiring is covered, dripping of condensed water from the heat insulating material could not be prevented.

The entire cross section of a set of these pipes and wires can be made into a cylindrical pipe structure surrounding the nonwoven fabric surface of the sheet-like heat insulating material of the present invention facing outward. At this time, by surrounding the outer periphery of the piping and wiring including the set of drain pipes with the heat insulating material of the present invention with the nonwoven fabric facing outward, the occurrence of dew condensation on the outer periphery of the piping is prevented. can do.

(Second embodiment: Example 4)
(Cylindrical piping structure in which the existing hot water supply piping and its protective pipe are surrounded by the heat insulating material of the present invention)
Further, the pipe structure cylindrically surrounded by the heat insulating material of the present invention is not limited to the refrigerant pipe for a heat exchanger as described above. As shown in FIG. 5(a), a water/hot water supply cylinder in which a protective member of the present invention is arranged on the outer circumference of a resin sheath pipe 17 as a protective pipe for the outer circumference of a crosslinked polyethylene pipe 15 as a water/hot water supply pipe. 19a. As in the tubular piping structure for the refrigerant of the heat exchanger, both ends of the tubular heat insulating material 14 wound around the piping are fixed by heat sealing, double-sided tape, or the like.

Here, in the case of a conventional existing water and hot water supply pipe, the piping structure is such that the outer circumference of the crosslinked polyethylene pipe 15, which is the water and hot water supply pipe, is covered with the corrugated resin sheath pipe 17, which is the protection pipe. However, the outer peripheral portion of the hot water supply pipe does not have a piping structure in which the foam sheet 18 covers the outer peripheral portion. Therefore, when only the resin sheath tube 17 is covered as a protective tube, dew condensation may occur on the outer surface of the sheath tube 17 exposed to the outermost layer depending on the usage environment. By enclosing the outer periphery of the resin sheath pipe in a cylindrical shape with the heat insulating material of the present invention, it is possible to obtain the effect of preventing the occurrence of dew condensation on the outer periphery of each pipe and the outer periphery of the wiring. It is possible to prevent dripping of condensed water from the part.

By using the heat insulating material of the present invention to form a cylindrical pipe structure in which the outer peripheral portion of a resin sheath pipe as a protective pipe for the water and hot water supply pipe is surrounded by the protective member of the present invention, the water and hot water supply pipe is a sheath pipe. It is possible to prevent dripping of condensed water, which is expected when used in a severe environment with the only one covered.

Furthermore, FIG. 5(b) shows a cylindrical pipe structure 19b in which the outer peripheral portion of the resin sheath pipe protecting the crosslinked polyethylene pipe of FIG. 5(a) is covered with a cylindrical heat insulating material 14 covered with resin foam good too. As shown in FIG. 5(b), the outer peripheral portion of the resin sheath pipe that protects the crosslinked polyethylene pipe serving as the hot water supply pipe may be covered with a resin foam 7, and the outer peripheral portion of the resin foam 7 may be further A tubular pipe structure covered with the tubular protective member 14 of the present invention may be employed. By adopting such a structure, it is possible to more reliably prevent dew condensation from occurring on the outer peripheral portion of the hot and cold water supply pipe.

(Second embodiment: Example 5)
(Pipe structure applying the protection member of the present invention to a vertical pipe and method for forming the same)
In the case of the piping covered so that the MD direction of the heat insulating material of the present invention coincides with the horizontal direction, dripping of condensed water is not observed. In the case of piping, it is conceivable that both the suction effect due to surface tension and the sedimentation and dripping of condensed water due to gravity compete with each other. An experiment was conducted to confirm problems such as the presence or absence of dew condensation when the piping of the present invention is used as a vertical piping.

FIG. 6 shows a piping structure in which the protection member of the present invention is applied to vertical piping. FIG. 6 shows a substantially U-shaped pipe in which vertical pipes are provided substantially symmetrically on both sides of a horizontal pipe in a constant temperature and humidity chamber. This pipe is provided with a 25 cm left vertical pipe 20 that descends vertically to the left of the center of the horizontal pipe, passes through a horizontal pipe 22 of about 30 cm, and rises vertically to the right of the horizontal pipe 25 cm to the right. A vertical pipe 21 is provided.

In FIG. 6, the vertical pipes 20 and 21 on the left and right sides are wrapped with a heat insulating material, and the entire pipe is placed in a constant temperature bath with a temperature of 35 ° C. and a humidity of 90%. A confirmation experiment was conducted to confirm the presence or absence of condensed water by circulating the refrigerant. The piping structure including vertical piping in this case is shown. Here, the weight of the condensed water in each pipe was measured by measuring the weight change of the tray 23 before and after the test in which the tray 23 was arranged at the bottom of the vertical pipe and the condensed water 24 was collected in the tray 23 .

The heat insulating material X is a heat insulating material using a nonwoven fabric that satisfies only the effective tensile stress in the MD direction in a tensile test of 25 MPa or less and 1 MPa or more. The heat insulating material Y is a heat insulating material for preventing dripping of condensed water that satisfies effective tensile stresses of 25 MPa or less and 1 MPa or more in both the MD direction and the TD direction.

As a result, the vertical pipe wound so that the MD direction of the heat insulating material X coincided with the vertical direction started dripping in 1 hour after being placed in the constant temperature bath, and 40.9 g of dripping water dripped in 15 hours. On the other hand, in the vertical pipe in which the heat insulating material Y was wound so that the MD direction coincided with the vertical direction, no condensation water dripped even 15 hours after placing the heat insulating material in the constant temperature bath. Here, the heat insulating material X is a heat insulating material corresponding to the test material 14 in Table 3, and the heat insulating material Y is a heat insulating material satisfying the test material 17 in Table 3.

Also, when the heat insulating materials of test materials 17, 18, and 19 in Table 3 were similarly wound around vertical pipes, no dripping of condensed water occurred. The reason for this is that, in the case of the heat insulating materials of test materials 16 to 19, the effective tensile stress in both the MD direction and the TD direction satisfies 25 MPa or less and 1 MPa or more, so that the water retained by the nonwoven fabric is transferred in the horizontal direction, which is the TD direction. It is considered that the condensed water did not occur because the water moved and transpiration occurred. For this reason, as a heat insulating material covering the vertical pipe, a vertical pipe structure that prevents dripping of condensed water can be obtained by covering the heat insulating material that satisfies the effective tensile stress of 25 MPa or less and 1 MPa or more in both the MD and TD directions. .

Further, when the heat insulating material for preventing dripping of condensed water is wrapped around the outer periphery of the refrigerant pipe and the pipe is a vertical pipe, the effective tensile stress of the heat insulating material for preventing dripping of condensed water is 25 MPa or less and 1 MPa. It is possible to obtain a method of forming a vertical pipe characterized by arranging at least one of the directions satisfying the above in a horizontal direction perpendicular to the direction of the vertical pipe. In this way, by covering the piping with a heat insulating material that satisfies an effective tensile stress of 25 MPa or less and 1 MPa or more in the horizontal direction, it is possible to avoid using a heat insulating material that satisfies an effective tensile stress of 25 MPa or less and 1 MPa or more in the TD direction. In both cases, substantially the same effect as in the case of using a heat insulating material that satisfies the effective tensile stress in the TD direction of 25 MPa or less and 1 MPa or more can be obtained, and dripping of dew condensation water can be prevented. This is considered to be due to the effect of facilitating evaporation of dew condensation water adsorbed or retained on the nonwoven fabric surface from the nonwoven fabric surface.

(Third embodiment: Application of the heat insulating material of the present invention to a structure for preventing dripping of condensed water of building members)
As examples of application of the heat insulating material of the third embodiment of the present invention to building members, examples 1 to 3 include a structure for preventing dripping of condensed water in a duct, a structure for preventing dripping of condensed water in inorganic building materials, and a structure for preventing dripping of condensed water in inorganic building materials. 1 shows a drip prevention structure for condensed water on a shingle roof.

(Third Embodiment: Example 1)
(Structure for preventing dripping of condensed water from duct and method for forming the same)
FIG. 7 shows a structure 30 for preventing dripping of condensed water of the duct body 29 using the heat insulating material 3 of the present invention. A rectangular parallelepiped duct having a thickness of 25 cm, a length of 30 cm, and a height of 30 cm was prepared, and the surface of the foam 7 on the back side of the heat insulating material was placed on the surface of the duct main body 29 so that the nonwoven fabric forming surface of the heat insulating material was placed on the surface of the duct body 29. By bonding to the duct main body 29 with an adhesive, a structure in which the nonwoven fabric forming surface 8 of the outer surface of the heat insulating material 3 is covered with the nonwoven fabric 8 of the heat insulating material over the entire surface of the duct main body 29 was produced. This structure is placed in a constant temperature and humidity chamber, and a refrigerant gas is flowed into the duct under the same conditions as in the case of the pipe structure for preventing dripping of condensed water in the vertical pipe of Example 5 of the second embodiment, A confirmation test was conducted to prevent dripping of condensed water. As a result, the same results as in the case of vertical pipes for refrigerant were obtained.

As a result of this test, the dripping behavior of condensed water on the surface of the duct showed different behavior depending on the type of heat insulating material covering the outer surface of the duct. For example, when using a heat insulating material that satisfies the effective tensile stress of 25 MPa or less and 1 MPa or more in both the MD direction and TD direction of test materials 16 to 19, it was confirmed that there was no condensation water dripping from the outer circumference of the duct. was done. In addition, a heat insulating material that satisfies the effective tensile stress of 25 MPa or less and 1 MPa or more only in the MD direction like the test materials 14 and 15 and has an effective tensile stress of 1 MPa or less only in the TD direction was placed on the side of the duct with the MD direction upward. Condensed water dripping was observed when it was placed in the opposite direction. When the heat insulating materials of the test materials 14 and 15 were formed on the side of the duct with the TD direction oriented horizontally, dripping of condensed water was not observed. In order to prevent dripping of condensed water from such a duct, the effective tensile stress of the heat insulating material for preventing dripping of condensed water is set to the vertical direction of the side wall of the duct in at least one direction that satisfies the effective tensile stress of 25 MPa or less and 1 MPa or more. A method of forming a structure of ducts arranged in a horizontal direction perpendicular to the parallel direction can also be used.

(Third Embodiment: Example 2)
(Structure for preventing dripping of condensed water from inorganic building board material and method for forming the same)
FIG. 8A shows a structure 27 for preventing dripping of condensed water in the horizontal direction of the inorganic building board 26 in which a heat insulating material for preventing dripping of condensed water is arranged on the surface of the inorganic building board 26 . At this time, a condensed water drip prevention structure of an inorganic building board material may be used in which the opposite surfaces of the heat insulating material 3 for preventing the dripping of condensed water and the inorganic building board material 26 are adhered to each other. In the present invention, at least one of a gypsum board and a calcium silicate board can be used as the inorganic building board material 26 . The state of use in this case corresponds to the heat insulating material portion on the upper surface of the duct in Example 1 of the third embodiment. For this reason, it is necessary to consider the downward movement of condensed water due to gravity for the non-woven fabric used for the structure 27 for preventing dripping of condensed water in the horizontal direction of the inorganic building board placed on the surface of the inorganic building board 26 . Therefore, a nonwoven fabric that satisfies an effective tensile stress of 25 MPa or less and 1 MPa or more in the MD direction at 5% elongation in a tensile test may be used. By adopting such a structure, it becomes possible to prevent dew condensation on the surface of the gypsum board and calcium silicate board when they are horizontally arranged.

FIG. 8(b) shows the vertical direction of condensed water on an inorganic building board material 26 with a heat insulating material 3 for preventing dripping of condensed water being adhered to the surface and arranged vertically as a vertical wall. 2 shows the anti-drip structure 28 of FIG. In this case, as can be seen from the experimental results for the duct in FIG. A vertical wall on which a heat insulating material is placed 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 direction and TD direction of the nonwoven fabric used for the heat insulating material, but not 25 MPa or less and 1 MPa or more. need to be structured.

In this case, the tensile effective stress value as the mechanical properties in both directions of the nonwoven fabric used as the building material for vertical walls must satisfy the above constraints. The reason for this is that the condensed water drips from the lower part of the heat insulating material placed vertically on the surface of the inorganic building board material, so it seems to accelerate the transpiration from the nonwoven fabric surface by promoting the movement to the side of the nonwoven fabric. Secondly, it is necessary to set the effective tensile stress in the TD direction within a predetermined range to provide a nonwoven fabric structure that prevents dripping of condensed water. In addition to the above, in order to form the structure 28 for preventing dripping of condensed water in the vertical direction of the inorganic building board material 26 arranged vertically as a vertical wall, the same procedure as in the case of the duct is performed. In addition, at least one of the directions that satisfies the effective tensile stress of the heat insulating material for preventing dripping of dew condensation water of 25 MPa or less and 1 MPa or more is oriented in a horizontal direction orthogonal to the direction parallel to the vertical direction of the inorganic building board. It is also possible to adopt a forming method that

(Third Embodiment: Example 3 - Condensed Water Drop Prevention Structure for Folded Plate Roof and Method for Forming the Same)
FIG. 9 shows a structure 32 for preventing dripping of condensed water on a folded-plate roof 31, which is formed by bending a steel plate in which the non-woven fabric 8 of the heat insulating material 3 of the present invention is laminated on the lower surface of the steel plate of the folded-plate roof 31. As shown in FIG. The folded-plate roof 31 is generally formed into a substantially V-shaped repeated shape with upper and lower sides having a predetermined width and oblique sides sandwiching the upper and lower sides. For example, in one cycle, the roof is molded to a height of 160 to 180 mm and a width of about 500 mm.

For example, as a condensation test simulating the use of a folded plate roof, a 0.8 mm thick Galvalume steel plate (registered trademark) was used, and a nonwoven fabric satisfying predetermined mechanical properties was laminated to the surface of the polyethylene resin foam. By using a structure to which a heat insulating material is adhered, a drip prevention structure for condensed water on a folded plate roof can be realized.

Similarly, in the case of using the structure for preventing dripping of condensed water for the folded-plate roof of FIG. It is necessary to use a heat insulating material that satisfies effective tensile stress of 25 MPa or less and 1 MPa or more in both directions. When test materials 16 to 19 in Table 3 were used as actual roof materials, it was confirmed that there was no dripping of dew condensation water from the nonwoven fabric on the surface of the heat insulating material under the folded plate roof.

In addition, as in test materials 14 and 15, the effective tensile stress in the MD direction only satisfies 25 MPa or less and 1 MPa or more. Condensed water was dripping from the surface of the heat insulating material on the slope of the lower part. Even with these heat insulating materials, by attaching the MD direction to the back surface of the folded plate roof in the direction perpendicular to the bending direction of the folded plate roof, condensation water from the nonwoven fabric on the surface of the heat insulating material can be prevented from dripping. Therefore, in order to obtain a structure for preventing dripping of condensed water from a folded-plate roof, it is necessary to bend the folded-plate roof in at least one direction in which the effective tensile stress of the heat insulating material for preventing dripping of condensed water satisfies 25 MPa or less and 1 MPa or more. , and a forming method that satisfies this requirement.

Here, FIG. 10(a) shows the nonwoven fabric 4 of the test material 4 as a representative example of the nonwoven fabric excellent in preventing the dripping of condensed water as a typical example of the material that did not cause the dripping of condensed water in the condensation confirmation test. The results of SEM observation at a magnification of 100 are shown. It can be seen that the nonwoven fabric 4 has many bends and a highly crimpable structure. Although no particular photograph is shown, on the other hand, the nonwoven fabric 1 used as the test material 1 in which the condensation water dripped was found to have relatively few bends and low crimpability. In addition, FIG. 10(b) shows the result of observing the condition of the nonwoven fabric 4 excellent in preventing the dripping of condensed water by observing the state of the nonwoven fabric at a magnification of 100 after water absorption. It can be seen that a water film is formed so as to connect the three-dimensional structure of the bent portions of the fibers of the nonwoven fabric, and as a result, the nonwoven fabric retains the condensed water. FIG. 10(c) shows an SEM photograph of the nonwoven fabric made of diagonal fibers of the test material 19 at a magnification of 100. From this photograph, the horizontal direction ( (corresponding to the TD direction) fiber flow appears to be stronger. FIG. 10(d) shows the case of a nonwoven fabric using short fibers corresponding to the test material 18. In this case also, the horizontal fiber flow in the photograph in the field of view is similar to that in FIG. 10(a). It can be seen that the As a result, even if the MD direction of the heat insulating material is aligned with the vertical direction and it is used in a structure with many vertical components in a normal usage method, the moisture retained on the fiber surface and the entangled part of the fiber moves in the TD direction. By promoting the uniformity in the nonwoven fabric, the evaporation of the retained water is promoted, and as a result of suppressing the condensation of the condensed water on the lower fibers, the dripping of the condensed water is prevented. It is considered to be a thing. Here, the fiber diameter of the pulp fibers in the field of view appears to be about 40 μm, but since the pulp fibers are beaten by crushing the pulp, the fiber thickness is 10 μm or less. The fiber diameter (average of dimensions in the width direction and thickness direction of the pulp) was 30 μm or less, which generally satisfied the range of the fiber diameter in the present application.

As described above, in the present invention, by making the non-woven fabric fused to the surface of the heat insulating material into a predetermined structure, the heat insulating material for preventing dripping of condensed water, the pipe structure for preventing dripping of condensed water using the heat insulating material, and the dripping prevention of condensed water. It was confirmed that a nonwoven fabric used for air conditioning duct structures, folded-plate roof structures for preventing dripping of condensed water, and heat insulating materials for preventing dripping of condensed water can be obtained. In addition, when observing the results of SEM photograph observation of Example 4, which is excellent in preventing dripping of condensed water, a water film is formed so as to connect the three-dimensional structure of the fibers of the nonwoven fabric, and as a result, the nonwoven fabric retains the condensed water. I know there is.

Furthermore, in the present invention, as an application to a structure for preventing dripping of condensed water from a vertical pipe of a heat insulating material or a building member, the invention of a method for forming these structures when these structures are formed in the vertical direction was described. It is also possible to make an invention of a method of using a heat insulating material for these vertical pipes or construction members to prevent dripping of condensed water.

In addition to the above, 2.5 μml (one drop) of tap water was dropped on the nonwoven fabric, and the water absorption speed measurement test was performed to measure the time until the water permeated. 30 seconds of immersion and measuring the length that ran up the nonwoven fabric, measuring the length of water absorption length measurement test, using nonwoven fabric in strips of a predetermined size, 23.5 ° inclined plastic (acrylic A test was conducted to determine the water propagation speed (cm/min/0.3 mL) for 60 seconds on the plate surface, but there was no correlation with dew condensation in any of the tests.

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 influenced by the above-described embodiments. It is obvious that a person skilled in the art can conceive various modifications or modifications within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. be understood to belong to

1. Constant temperature constant temperature bath 2 . Refrigerant pipe (stainless steel pipe, copper pipe)
3. Insulation material4. temperature measurement points5. drip sensor6. refrigerant7. resin foam8. Non-woven fabric9. Embossed portion 10. Glasses-type piping structure 10a, 10b Piping structure 11. heat-sealed part 12 . drain pipe 13 . Wiring 14 . cylindrical heat insulating material 15 . cross-linked polyethylene tube 16 . Refrigerant cylindrical piping structure 17 . Resin sheath tube 18 . Foam 19a, 19b: Tubular piping structure for hot water supply 20. Left vertical pipe 21 . Right vertical pipe 22 . horizontal piping 23 . tray 24 . Condensed water25. Thermal insulation surface (non-woven fabric)
26. Inorganic building board materials 27 . Structure for preventing dripping of condensed water in the horizontal direction of the inorganic building board material28. Structure for preventing dripping of condensed water in the vertical direction of the inorganic building board 29. metal duct 30 . Structure for preventing dripping of condensed water in duct 31. Metal folded plate 32 . Structure to prevent dripping of condensed water from metal folded plates

Claims (29)

A heat insulating material for preventing dripping of condensed water in which a nonwoven fabric is arranged on the surface of a polyethylene resin foam, the base material is a polyethylene resin foam having sheet-like closed cells, and one surface of the base material has The nonwoven fabric is fused or bonded, 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 is 85 to 98%, and the nonwoven fabric is measured in the MD direction in a tensile test. A heat insulating material for preventing dripping of dew condensation water, wherein an effective tensile stress, which is a value obtained by dividing an apparent stress in the same direction at a tensile elongation value of 5% by a filling ratio, satisfies 25 MPa or less and 1 MPa or more. The nonwoven fabric of the heat insulating material has a thickness of 1.0 mm or less as measured according to JISL1913, and a water retention capacity of 500 g/m ² or more per 1 mm of apparent thickness of the nonwoven fabric. 2. The heat insulating material for preventing dripping of condensed water according to 1. 3. The condensed water according to claim 1 or 2, wherein the fibers constituting the nonwoven fabric of the heat insulating material are made of fibers containing at least one of PET resin, polyethylene resin, polypropylene resin, and acrylic resin. Insulation material for drip prevention. 4. The heat insulating material for preventing dripping of condensed water according to claim 3, wherein the fibers constituting the nonwoven fabric of the heat insulating material further contain any one of cellulose fiber, pulp, and rayon fiber in an amount of 30% or less of the total weight of the fibers. At least 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 core-sheath structure are fibers having a hollow core, and the hollow fibers It is a multi-layer structure fiber in which a sheath is formed around the core, and the sheath of the fiber forming the core or the hollow core is formed of a resin having a lower melting point than the core. The heat insulating material for preventing dripping of dew condensation water according to claim 3 or 4. 6. The heat insulating material for preventing dripping of dew condensation water according to any one of claims 1 to 5, wherein the nonwoven fabric formed on the surface of the resin foam is embossed. A heat insulating material for preventing dripping of condensed water according to any one of claims 1 to 6, wherein the value of tensile elongation in the TD direction in a tensile test is a value obtained by dividing the apparent stress in the same direction at 5% by the filling rate. A heat insulating material for preventing dripping of condensed water, characterized by satisfying an effective tensile stress of 25 MPa or less and 1 MPa or more. 8. A pipe characterized in that the heat insulating material for preventing dripping of condensed water according to any one of claims 1 to 7 is coated with a non-woven fabric on the outer periphery of the refrigerant pipe toward the outer peripheral surface. The two pipes are integrated by heat-sealing or heat-bonding the heat insulating material for preventing dripping of condensed water coated on the outer periphery of the refrigerant pipe according to claim 8 to each other. A spectacles-type piping structure characterized by: A plurality of refrigerant pipes, drain pipes, and parts to be installed in the wiring pipes are prepared, and the heat insulating material for preventing dripping of condensed water according to any one of claims 1 to 7 is provided on the outer peripheral surface of the nonwoven fabric forming surface. As a result, the plurality of refrigerant pipes, drain pipes and wiring are surrounded so that the outer peripheral surface shape of the heat insulating material for preventing dripping of condensed water has a substantially cylindrical cross section, so that the parts inside the pipes are prevented from condensation. 1. A cylindrical piping structure for refrigerant piping, characterized in that it is housed inside a heat insulating material that prevents dripping of water. A crosslinked polyethylene pipe and a resin sheath pipe covering the outer periphery of the crosslinked polyethylene pipe are prepared as a water supply and hot water supply pipe, and the crosslinked polyethylene pipe and the resin sheath pipe covering the outer periphery of the crosslinked polyethylene pipe are surrounded. 8. The condensed water dripping preventing heat insulating material according to claim 7 has a non-woven fabric forming surface as an outer peripheral surface, and the condensed water dripping preventing heat insulating material has an outer peripheral surface shape of a substantially cylindrical cross section. A cylindrical piping structure for water supply and hot water supply, characterized in that said crosslinked polyethylene pipe and said sheath pipe are housed inside said dripping prevention heat insulating material. 12. The tubular pipe structure for water supply and hot water supply according to claim 11, wherein the resin sheath pipe is covered with a resin foam so as to surround the outer circumference of the sheath pipe. A piping structure in which the outer periphery of the refrigerant pipe is covered with the heat insulating material for preventing the dripping of the condensed water, wherein at least a part of the pipe includes a vertical pipe, and the dripping of the condensed water according to claim 7 is included in the vertical pipe. A pipe structure of a vertical pipe, wherein the non-woven fabric forming surface of the heat insulating material is covered with the vertical pipe so as to be the outer peripheral surface. 8. The structure of an air-conditioning duct, wherein the heat insulating material for preventing dripping of condensed water according to claim 7 is adhered to the outer surface of the air-conditioning duct with the non-woven fabric forming surface facing the outer surface. The heat insulating material for preventing dripping of condensed water according to any one of claims 1 to 7 is placed on the surface of the inorganic building board material with the nonwoven fabric forming surface as the outer surface, and furthermore, the inorganic building board material The resin foam surface of the heat insulating material for preventing dripping of condensed water placed on the surface of the nonwoven fabric forming surface as the outer surface and the surface of the inorganic building board facing each other are adhered to each other and arranged in the horizontal direction. and wherein the inorganic building board material is at least one of a gypsum board and a calcium silicate board. 8. The heat insulating material for preventing dripping of condensed water according to claim 7 is placed on the surface of an inorganic building board with the non-woven fabric forming surface as the outer surface, and the resin foam surface of the heat insulating material for preventing dripping of condensed water and the inorganic The inorganic building board materials are arranged in the direction of a vertical plane, and the inorganic building board material is at least one of a gypsum board and a calcium silicate board. A structure for preventing dripping of condensed water of an inorganic building board material, characterized in that it is any one of the above. 8. A structure for preventing dripping of condensed water on a folded plate roof, wherein the heat insulating material for preventing dripping of condensed water according to claim 7 is adhered to an inner surface of the folded plate roof. 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 is 85 to 98%, and the thickness of the nonwoven fabric measured according to JISL1913 is 1.0 mm or less. Further, a nonwoven fabric for preventing dripping of condensed water, characterized in that the value obtained by dividing the apparent stress in the MD direction when the value of tensile elongation in the MD direction in a tensile test is 5% by the filling ratio satisfies 25 MPa or less. Condensed water characterized in that the nonwoven fabric according to claim 18 has a water retention amount converted to 1 mm of apparent thickness of 500 g/m ² or more, and is used by being fused to the surface of a polyethylene resin foam. Non-woven fabric for drip prevention. The fibers constituting the nonwoven fabric are composed of fibers containing at least one of PET resin, polyethylene resin, polypropylene resin, or acrylic resin, and the fibers are composed of fibers that do not have a core-sheath structure. The nonwoven fabric for preventing dripping of condensed water according to claim 18 or 19. 21. The nonwoven fabric for preventing dripping of condensed water according to claim 20, wherein the fibers constituting said nonwoven fabric further contain any one of cellulose fibers, pulp and rayon fibers in an amount of 30% or less of the total weight of the fibers. At least part of the fibers constituting the nonwoven fabric includes fibers having a core-sheath structure, and the sheath of the fibers having the core-sheath structure is formed of a resin having a lower melting point than the core, or the fibers have a core-sheath structure. The core fiber of the fiber is a hollow fiber, and the hollow multi-layer structure fiber has a sheath formed around the hollow fiber, and the core or the sheath of the fiber forming the hollow core is located closer to the core. 22. The nonwoven fabric for preventing dripping of condensed water according to any one of claims 18 to 21, wherein the nonwoven fabric is made of a resin having a low melting point. (20) to (20), wherein at least a part of the fibers constituting the nonwoven fabric is formed of staple fibers, or formed of weft or weft orthogonal filaments or weft or weft oblique filaments. 23. The nonwoven fabric for preventing dripping of condensed water according to any one of 22. The nonwoven fabric has an effective tensile stress of 25 MPa or less and 1 MPa or more, which is the value obtained by dividing the apparent stress in the same direction when the value of tensile elongation in the MD direction and TD direction in a tensile test is 5%, respectively, by the filling rate. 24. The nonwoven fabric for preventing dripping of condensed water according to claim 23, wherein both are satisfied. Claim 23 or Claim 24, wherein the staple fiber nonwoven fabric is manufactured by a chemical bond method, a thermal bond method, a spunlace method, an air laid method, a needle punch method, or the like. Non-woven fabric for drip prevention. A construction method for a piping structure in which the heat insulating material for preventing dripping of condensed water according to any one of claims 1 to 7 is wound around the outer periphery of a refrigerant pipe, wherein the pipe is a vertical pipe or an oblique pipe. A method of forming a piping structure, wherein the direction in which the effective tensile stress of the heat insulating material for preventing dripping of condensed water satisfies 25 MPa or less and 1 MPa or more is oriented in a horizontal direction orthogonal to the direction of the vertical piping. In the method for forming a structure for preventing dripping of condensed water in an air-conditioning duct, the side surfaces of the air-conditioning duct are provided facing each other so as to sandwich the upper and lower surfaces of the duct in at least a vertical direction, and the side surfaces include: The direction in which the effective tensile stress of the nonwoven fabric of the heat insulating material for preventing dripping of condensed water according to any one of claims 1 to 7 satisfies 25 MPa or less and 1 MPa or more is oriented in the horizontal direction orthogonal to the vertical duct side surface. A method for forming a drip prevention structure for condensed water in an air conditioning duct, characterized by: 8. The method for forming a structure for preventing dripping of condensed water from an inorganic building material for construction, wherein the structure for preventing condensation from dripping from the inorganic building material for construction is a vertical wall structure, according to any one of claims 1 to 7. On the surface of the vertical wall of the inorganic building material for construction, the direction in which the effective tensile stress of the nonwoven fabric of the heat insulating material for preventing dripping of condensed water satisfies 25 MPa or less and 1 MPa or more is oriented in the horizontal direction perpendicular to the direction of the vertical wall structure. A method for forming a structure for preventing dripping of condensed water of an inorganic building material for construction, characterized in that the nonwoven fabric of the heat insulating material is arranged as an outer surface. In a method for forming a structure for preventing dripping of condensed water on a folded plate roof, the effectiveness of the nonwoven fabric of the thermal insulation material for preventing dripping of condensed water according to any one of claims 1 to 7 The nonwoven fabric of the heat insulating material is arranged as the outer surface on the back surface of the folded plate roof so that the direction that satisfies a tensile stress of 25 MPa or less and 1 MPa or more is perpendicular to the bending direction of the folded plates of the folded plate roof. A method for forming a drip prevention structure for condensed water on a folded plate roof.

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