JP2008267690A - Fireproof or fire-retardant heat insulating resin duct - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fireproof or fire-retardant duct without the problems of a conventional fireproof duct used in homes and buildings having a metal pipe surrounded by nonorganic fibers represented by glass fibers covered by a heat insulating material, which is heavy and has problems in workability and pressure loss. <P>SOLUTION: In a flexible duct for air conditioning that is fireproof or fire-retardant having an inner pipe including a wall-thickness part made of a non-woven fabric and a ring-like or spiral core material made of a thermoplastic hard resin, a heat insulating layer laminated thereon, and an airtight layer laminated further thereon, a resin foamed layer subjected to a fire-retardant treatment as the heat insulating layer, or a thermoplastic fiber layer subjected to a fire-retardant treatment is used. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is preferably used for air ducts and ventilation ducts for air conditioning and ventilation in buildings, is highly flexible, has good workability, has little collapse of the heat insulating layer during combustion, and has excellent flame retardancy or incombustibility. Furthermore, it is related with the heat insulation resin duct with little pressure loss.

  Conventionally, a flame-retardant or non-flammable heat insulating duct has been generally used as a ventilation duct, and the structure thereof includes a heat insulating layer and a non-flammable surface outside the inner tube formed by spirally winding a thin steel plate. A laminate of materials is known. In this incombustible or incombustible heat insulating duct, a fiber layer made of inorganic fibers such as glass fiber or rock wool is used as a heat insulating layer, and a galvanized steel plate or a stainless steel steel plate is generally used as an inner pipe (Patent Literature). 1 and 2).

  However, when fiberglass or rock wool is cut, fiber cut pieces are scattered, which is problematic for safety and hygiene. Furthermore, thin steel sheets are difficult to cut on site, and because the irregularities on the inner surface of the duct are large, the pressure loss is large. There are also problems. Furthermore, resin-made ducts can be considered as non-combustible or flame-retardant ducts, but resin-made ducts generally have a problem that the shape of the heat insulating layer easily collapses due to heat under combustion conditions. . When the shape of the heat-insulating layer easily collapses due to heat under combustion conditions, there is a problem that combustion to the peripheral members of the duct is promoted due to the occurrence of a fall accident due to the collapse and the falling off of the duct during a fire.

JP 09-243155 A JP 2001-343146 A

  The object of the present invention is that glass wool and metal plates are not used, and work on site is possible, and safety, workability, energy saving of the system can be realized, pressure loss is small, nonflammability or flame retardancy The object is to provide an incombustible duct that is extremely useful as an air conditioning duct for houses and buildings. Another object of the present invention is to provide a resinous duct in which the shape of the heat insulating layer does not easily collapse even under the combustion condition of the duct.

  The object of the present invention is to laminate a heat-insulating layer on an inner tube made of a ring-shaped or spiral core material made of a non-woven fabric and a thermoplastic hard resin, and further, an airtight layer is laminated thereon. A non-flammable or flame-retardant heat-insulating resin characterized in that a flame-retardant treated resin foam layer or a flame-retardant treated thermoplastic fiber layer is used as the heat-insulating layer in the air-conditioning flexible duct Achieved by ducts.

In the present invention, a non-woven fabric is used as the meat part of the inner tube. As the non-woven fabric, a non-woven fabric subjected to a flame retardant treatment is preferable, and a glass fiber woven fabric or a flame retardant resin film in which an airtight layer is laminated with a metal foil. It is preferable that the flame retardant applied to the heat insulating layer is a boric acid flame retardant, and the nonwoven fabric constituting the inner tube may be impregnated with a boric acid flame retardant. Preferably, aluminum hydroxide or magnesium hydroxide is further kneaded into the thermoplastic hard resin constituting the core material.
Further, in the present invention, it is more preferable that the flame retardant used in the core material is aluminum hydroxide or magnesium hydroxide, and the flame retardant used in the heat insulating layer is a boric acid flame retardant. As mentioned.

  Conventional non-combustible ducts for air conditioning generally use glass wool as a heat insulating material and a metal core as a core, which is excellent in non-combustibility, but is hygienic due to scattering of glass wool when the duct is cut. Due to the above problems, the metal core material was difficult to cut and was subjected to on-site workability. By using the metal core material, the irregularities inside the duct were large, resulting in poor pressure loss. Moreover, since the metal is heavier than the resin, the duct using the metal core material is heavier than the resin duct and is inferior in workability.

  According to the present invention, a resin duct excellent in workability, pressure loss property, and safety and health can be provided as an air-conditioning incombustible or incombustible duct for a house or building. The duct of the present invention is expected to play an active role in fields such as detached houses, apartment houses, and air conditioning ducts for buildings.

Next, the present invention will be described with reference to the drawings.
FIG. 1 is a side view showing an example of the incombustible or flame-retardant heat-insulating resin duct of the present invention. The incombustible or flame-retardant heat-insulating resin duct is a spiral part made of a non-flammable meat part 3 and a hard resin. An inner tube in which a core material 4 is integrated by fusion bonding or bonding with an adhesive, and a heat insulating layer 1 and an airtight layer 2 covering the outside.

  The nonwoven fabric constituting this inner tube is made of synthetic fibers obtained from fiber-forming thermoplastic resins such as polypropylene, polyethylene, polyethylene terephthalate, etc., in terms of melt adhesion to the core material and recyclability. preferable. In particular, from the viewpoint of flexibility, versatility, and processability, it is a mixed spun fiber or a composite spun fiber of polypropylene and polyethylene, and a non-woven fabric composed of fibers in which polyethylene is present on the fiber surface or a mixture of polyethylene fiber and polypropylene fiber. A non-woven fabric, a non-woven fabric made of a mixed spun fiber of polyethylene terephthalate and polyethylene, or a composite spun fiber having polyethylene on the fiber surface, or a non-woven fabric made of a mixture of polyethylene fiber and polyethylene terephthalate fiber has duct formability. Is the best. In this case, the low-melting point polymer or the low-melting point polymer fiber works as a thermal binder component, and brings about the fixing of the shape of the nonwoven fabric and further the heat-fusibility with the core material. In particular, a fiber having a low melting point polymer and a high melting point polymer, such as a composite spun fiber or a mixed spun fiber using the above-described polyethylene component as a low melting point component, is a thermal binder fiber. It is also a suitable example to use as. In this case, the low melting point polymer existing on the fiber surface melts and adheres to the core material.

  It is also possible to use inorganic fibers such as glass fibers and rock wool as the fibers constituting the nonwoven fabric, but inorganic fibers are preferable because the fiber cut pieces are scattered in the air at the time of cutting, resulting in a worse working environment. It can not be said. Further, when a large impact is applied during work or after installation, the fiber pieces of the inorganic fibers may enter the duct depending on the case and may be mixed into the gas in the duct, which is not preferable.

The basis weight of the nonwoven fabric may include the 30 to 200 g / ^{m 2,} and more are preferred those 70~120g / ^{m 2.} In addition, the air permeability of the nonwoven fabric is preferably in the range of 30 to 120 cc / cm ² / sec as measured by the Frazier method from the viewpoint of noise reduction and pressure loss performance. The nonwoven fabric may be any of spunbonded nonwoven fabric, melt blown nonwoven fabric, wet nonwoven fabric, water-impregnated nonwoven fabric, needle punched nonwoven fabric, and the like, and spunbonded nonwoven fabric is particularly preferable because of low strength and pressure loss. The thickness of the constituent fibers is preferably in the range of 1 to 5 dtex from the viewpoint of duct formability.

It is preferable that boric acid-based, phosphorus-based, or halogen-based flame retardant is fixed to the non-woven fabric constituting the inner tube in a solid content of 0.000001 g to 0.001 g per cm ^{2 of} the non-woven fabric. Of these, boric acid-based flame retardants are particularly preferred from the viewpoint of shape retention due to glass layer formation during heating. A specific example of the boric acid flame retardant is Fireless B (manufactured by Trust Life Co., Ltd.). When the blending amount of the flame retardant is less than 0.000001 g, it is difficult to achieve non-flammability or flame retardancy required as a duct. On the other hand, if it exceeds 0.001 g, the stability of the duct molding is lacking and the cost of the drug increases. The blending amount of the flame retardant is more preferably 0.000005 g to 0.0008 g. The flame retardant is usually applied at the nonwoven fabric stage.

  Next, as the resin constituting the core material, polyolefin resins such as polypropylene and polyethylene, polyester resins represented by polyethylene terephthalate, polyamide resins represented by nylon 6, vinyl resins such as acrylic and polystyrene, etc. A thermoplastic resin is exemplified, and among them, a rigid thermoplastic resin composed of carbon atoms and hydrogen atoms, or these atoms and oxygen atoms is preferable, and typically, polyethylene, polyester, polypropylene, polystyrene and the like are listed. It is done. In particular, polypropylene, polyethylene, and ethylene-propylene copolymer are preferable from the viewpoint of hardness, weather resistance, versatility, and polypropylene is most preferable.

As the hard resin, those having a hardness R scale (JIS K7202 R scale Rockwell hardness) in the range of 70 to 130 are preferably used.
The core material is formed by melting and extruding these resins with a cross-sectional area of 5 to 15 mm ² and turning them in a ring shape or a spiral shape to form an inner tube. The diameter (inner diameter) of the inner tube is preferably in the range of 50 to 300 mm. When the inner tube is formed in a ring shape or a spiral shape, the distance between adjacent core members is preferably in the range of 5 to 10 mm. In particular, in the present invention, it is preferable to spiral the core material. Also, as the cross-sectional shape of the core material, as shown in the attached figure, a shape like a two-stage structure in which an upper part having a narrower width than the base is placed on a base with a flat bottom is This is preferable because the adhesiveness and the helical shape are not easily crushed.

  Furthermore, in the spiral or ring-shaped core material, thick core materials and thin core materials exist alternately (that is, in the case of a spiral shape, a thick core material and a thin core material are used, as shown in FIG. It is preferable that the thick core material and the thin core material are alternately present) in that the flame retardancy and incombustibility of the duct can be effectively increased by increasing the installation area of the heat insulating layer and the core material. The thickness ratio between the thick core material and the thin core material is preferably in the range of 2: 1 to 4: 1 in terms of the cross-sectional area ratio. Moreover, it is preferable to throw a thick core material at intervals of 15 to 30 mm, and the thick core material and the thin core material are thrown into positions at which the space of 15 to 30 mm is divided at 70 to 55:30 to 45. From the viewpoint of low pressure loss. By maintaining this interval, it is possible to correct the amount by which the inner tube nonwoven fabric bends inside the duct when the duct is bent, and to prevent a significant drop in pressure loss during bending.

  Examples of the flame retardant used in the core material in the present invention include bromine compounds such as pentabromodiphenyl ether, octabromodiphenyl ether, decabromodiphenyl ether, tetrabromobisphenol A, hexabromocyclododecane, and phosphoric acid typified by triphenyl phosphate. Phosphorus compounds such as esters and red phosphorus, chlorine compounds such as chlorinated paraffin and polychlorinated biphenyl, antimony compounds such as antimony trioxide and antimony pentoxide, metal hydroxides such as aluminum hydroxide and magnesium hydroxide, etc. Aluminum hydroxide and magnesium hydroxide are preferably used because they can be used, workability, cost and flame retardancy, and the core material shape does not easily collapse under combustion conditions.

  It is preferable that the flame retardant is kneaded into the core-constituting resin at a ratio of 5 to 80% by weight with respect to the weight of the thermoplastic resin constituting the core. If the blending amount is less than 5% by weight, it is difficult to achieve the nonflammability required for the duct. On the other hand, if it exceeds 80% by weight, the stability of duct molding will be lacking. More preferably, it is the range of 10-50 weight%. Among the above flame retardants, aluminum hydroxide and magnesium hydroxide are particularly preferable in that they can decompose while causing an endothermic reaction in a fire, prevent the spread of fire, and maintain the core material shape.

  The heat insulation layer that covers the outside of the inner pipe is intended to prevent the heat of the gas flowing inside the inner pipe from being taken away to the outside, or to prevent external heat from being transferred to the inner pipe. A thermoplastic resin foam layer such as foam or polyethylene foam, or a thermoplastic fiber layer such as felt made of polyethylene fiber or polyester fiber is used. In a conventional duct, an inorganic fiber layer made of glass fiber or rock wool is used as a heat insulating layer. In the case of these inorganic fiber layers, the inorganic fiber is cut when the duct is cut, and the fiber layer Foamed layer made of the thermoplastic resin of the present invention, in which the detached fiber cut pieces are scattered in the air and deteriorate the working environment or the like, or are mixed into the air flowing in the duct and deteriorate the environment. Or in the case of a fiber layer, such work environment deterioration is not caused. The thickness of the foam layer or fiber layer is optimally 5 to 20 mm. In the case of a foam layer, a foam layer with an expansion ratio of 30 to 60 times is optimal.

  As the thermoplastic resin constituting the foam layer, thermoplastic resins such as polyethylene, polypropylene, polyurethane, polystyrene, and polyethylene terephthalate can be suitably used. Among them, polyurethane and polyethylene are particularly suitable for duct workability and environmental load. Are particularly preferred.

  In addition, when using a fiber layer, non-woven fabrics, woven fabrics, knitted fabrics and the like are mentioned, and among them, non-woven fabric layers such as spunbonded non-woven fabrics, melt blown non-woven fabrics, wet non-woven fabrics, water-impregnated non-woven fabrics, needle punched non-woven fabrics, and resin-bonded non-woven fabrics are preferable. A needle punch nonwoven fabric is particularly preferable. Examples of the thermoplastic resin constituting the fiber layer include polyolefin resins such as polyethylene and polypropylene, polyester resins represented by polyethylene terephthalate, and the like, and polyester resins are particularly preferable in terms of weight, cost, and ductability. . The thickness of the constituent fibers is preferably in the range of 0.1 to 20 dtex, more preferably in the range of 0.5 to 8 dtex, and is preferable in terms of duct workability.

In the present invention, it is essential that such a heat insulating layer, that is, a foamed layer or a fiber layer, is subjected to a flame retardant treatment. Examples of the flame retardant used include boric acid flame retardants, phosphorus flame retardants, halogens. In particular, boric acid flame retardants are preferably used in terms of safety to human bodies and environmental burden.
Specific examples of the boric acid flame retardant include compounds such as sodium borate, calcium borate, and zinc borate. Among these boric acid compounds, sodium borate particularly provides good flame retardancy. .

The adhesion amount of the flame retardant per cm ^{2 of the} heat insulating layer is preferably in the range of 0.001 to 0.2 g in terms of solid content. If the applied amount is less than 0.001 g, the nonflammability of the duct cannot be satisfied. On the other hand, if it exceeds 0.2 g, the duct forming stability is lacking and the flexibility of the duct is lost due to adhesion of the flame retardant. More preferably, it is in the range of 0.005 g to 0.05 g.

  In the present invention, as a part of the heat insulating layer, it is also possible to use glass wool, ceramic wool, rock wool, which are inorganic heat insulating materials. However, when the amount of use of such an inorganic heat insulating material increases, when cutting the duct, the cut pieces of these inorganic fibers are scattered in the air, and the working environment is deteriorated. It is preferable not to use any inorganic fiber.

  As the flame retardant agent impregnated in the heat insulating layer, it is desirable to use a boric acid flame retardant from the viewpoint of environmental load because the shape of the heat insulating layer can be maintained for a long time under combustion conditions. Here, as a suitable specific example of the boric acid flame retardant, an aqueous sodium borate solution (trade name: Fireless B) manufactured by Trust Life may be mentioned. When this flame retardant is used, the feature that the shape of the heat insulating layer is not particularly broken even under combustion conditions can be obtained.

  As described above, the flame retardant used in the core material is preferably aluminum hydroxide or magnesium hydroxide, which decomposes while causing an endothermic reaction in the event of a fire, and can prevent the spread of fire. As the flame retardant imparted to the layer, a boric acid flame retardant is preferable, but this boron flame retardant forms a foam glass layer in the event of a fire, maintains the shape of the heat insulating layer, and prevents secondary disasters due to collapse. be able to. Therefore, due to the combination of aluminum hydroxide or magnesium hydroxide used for the core material and the boron-based flame retardant applied to the heat insulating layer, the duct of the present invention has an endothermic reaction effect core material and shape retention effect. By combining a certain heat-insulating layer, it is possible to effectively prevent the spread of fire compared to the case where other flame retardants are used.

  In addition, when using aluminum hydroxide or magnesium hydroxide, if black or gray pigment is added about 1 to 5% by weight with respect to a thermoplastic resin such as polypropylene and aluminum hydroxide or magnesium hydroxide, it will change over time. Color change can be suppressed. As a duct, it is preferable in terms of appearance to suppress a change in color due to a change with time.

In the incombustible or flame-retardant heat insulating resin duct in the present invention, the heat insulating layer is covered with an airtight layer. The airtight layer covers the duct surface without directly exposing the heat insulating layer to the outside. In addition to preventing the outside air from entering the heat insulating layer, the airtight layer also plays a role of preventing the duct from heat. As an airtight layer, a thermoplastic resin film having an aluminum vapor deposition layer as the outermost surface layer, a metal foil such as an aluminum foil, a stainless steel foil, a copper foil, a zinc foil, a tin foil, and a silver foil, and a lamination of these metal foil and a thermoplastic resin film Body, laminating these metal foil and glass fiber fabric, laminating these metal foil and thermoplastic resin film, and further laminating glass fiber fabric, and coating with heat resistant resin represented by fluororesin Flame retardant resin film sheets represented by glass fiber fabrics, vinyl chloride sheets, etc. are used, but aluminum vapor-deposited thermoplastic resin films, especially aluminum vapor-deposited polyethylene terephthalate sheets, vinyl chloride resin films, aluminum foils are used because of cost and light weight. Laminated glass fiber woven fabric and fluororesin laminated glass fiber woven fabric are suitable, as well as heat resistance and nonflammability. Upon consideration, aluminum foil laminated glass fiber fabric is optimum. The thickness of the aluminum foil is 0.01 to 0.05 mm, the aluminum foil weight is 40 to 55 g / m ² , the aluminum purity is 90.0 to 99.9%, and the glass fiber fabric has a thickness of 0.10 to 0 .15 mm, weight 75-90 g / m ² , weave density 10-20 × 10-20 / 1 inch square (thread thickness 400-800 dtex), plain weave type, adhesion of aluminum foil and glass fiber fabric As the agent, a nonflammable acrylic emulsion resin is preferably used in terms of adhesiveness, nonflammability, and flame retardancy.

As a method for producing an incombustible or flame-retardant heat-insulating resin duct, for example, a meat part made of a nonwoven fabric is first wound around a rotating shaft of a tube forming machine, and a spiral core material made of a hard resin is melt extruded. An inner tube is formed by melt-bonding to a tubular meat portion made of the nonwoven fabric.
And the heat insulation layer is coat | covered linearly with respect to the duct longitudinal direction on the surface of an inner pipe. Moreover, the method of forming a heat insulation layer by winding the heat insulation layer slit to the same width as the core material space | interval of the incombustible or flame-retardant heat insulation resin duct inner pipe at the same time as inner pipe manufacture is formed. The inner tube and the heat insulating layer may be bonded, or may be integrated by a metal fitting, a wire or the like. Furthermore, the airtight layer to be present on the surface is coated with a heat insulating layer on the surface of the inner tube, and then the airtight layer is overlaid and fixed so as to cover the surface, or the heat insulating layer and the airtight layer are bonded in advance. Any method of previously integrating and covering the surface of the inner tube in the integrated state may be used. The hermetic layer and the heat insulating layer may be integrated by an adhesive or heat fusion, and further by a method such as a metal fitting or a wire.

  Further, in the present invention, the heat insulating layer may be partially provided on the surface of the inner tube, but the heat efficiency of the air conditioning system is improved and the cost is improved when the heat insulating layer is formed on almost the entire duct. This is preferable because it is advantageous and can effectively prevent condensation inside the duct.

  The non-flammable or flame-retardant resin duct of the present invention thus obtained is excellent in non-flammability, low pressure loss, silence, heat insulation and flexibility. It is used as a duct for conveying air for air conditioning in buildings, stores, warehouses, vehicles, ships and the like. The duct size mainly used is a diameter of 50 to 100 mm in a general house, and one having a diameter of 150 mm or more is used in an apartment house or a building air conditioner.

  In addition, as described above, the incombustible or flame-retardant heat-insulating resin duct according to the present invention has a meat part made of nonwoven fabric, an inner tube made of a core material, a heat-insulating layer, and an air-tight layer as essential constituent requirements. Other layers may be present in the inner tube, in the middle of these tubes and layers, and on the surface of the hermetic layer.

  EXAMPLES Examples will be shown below to explain the present invention more specifically and in detail. In Examples,% is a value based on weight unless otherwise specified.

Example 1
Nonwoven fabric (1) to be a meat part {The basis weight is 100 g / m ² , and the constituent fibers are polypropylene-polyethylene having a core-sheath structure of polypropylene and polyethylene, and having a fineness of 3 dtex in which polyethylene constitutes a sheath component A non-woven fabric (product name: Haibon product number: 6590 made by Shinwa) and hoe, which are made of a spunbonded nonwoven fabric made of core-sheath type composite fibers made by directly fusing the sheath components together at the time of melt spinning An acid flame retardant (manufactured by Trust Life) in an amount of 0.0008 g / cm ² (solid content) is wrapped around the rotating shaft of a tube molding machine to form a thermoplastic hard resin core material (spiral core material) 2) {Mixene hydroxide 50 wt% blended polypropylene (manufactured by Calp Kogyo Co., Ltd.)} is spirally wound from the top and heat-sealed, as shown in FIG. And an inner tube such.

Two types of core materials having different thicknesses were used as the core material. That is, the thicker core material has a cross-sectional area of 15 mm ² , the thinner core material has a cross-sectional area of 5 mm ² , and the cross-sectional shape is such that the bottom is flat on the base and the narrow upper part is placed. It has a shape like a two-stage structure. The thick core material and the thin core material are alternately present, and the thick core material is input at intervals of 25 mm, and the thin core material is input at a position where the 25 mm interval is divided at 60:40.

A flame retardant-added polyurethane foam (3) having a thickness of 10 mm and a density of 22.0 g / m ² that is a heat insulating layer on the outside, 0.05 g of a boric acid flame retardant (manufactured by Trust Life) on urethane foam (manufactured by Achilles) / cm ² (solid content) becomes fixed at impregnation} and airtight sheet aluminum foil laminated glass fabric (4) {aluminum foil thickness 0.02 mm, aluminum foil weight 54.2 g / ^{m 2,} an aluminum purity of 99.9 %, Glass fabric thickness 0.12 mm, glass fabric weight 86 g / m ² , glass fabric weave density 16 × 15/1 inch square (one thickness: 674 dtex), glass fabric and aluminum foil adhesive As a duct as shown in FIG. 1, a non-flammable acrylic emulsion resin is used (made by Wako heat insulating material)} as an airtight layer.

Example 2
In the said Example 1, the duct was manufactured by the same method as Example 1 except using the nonwoven fabric which has not provided the boric-acid type flame retardant as a nonwoven fabric which comprises an inner tube | pipe.

Example 3
In the said Example 1, the duct was manufactured by the same method as Example 1 except using a fluororesin coating glass fiber sheet {Fujiace (product number: FG-4300 Fujimori Kogyo make)} as an airtight layer.

Example 4
In the said Example 1, the duct was manufactured by the same method as Example 1 except using the polypropylene resin which does not mix | blend magnesium hydroxide as a core material.

Example 5
In Example 1 above, a duct was manufactured in the same manner as in Example 1 except that an aluminum vapor-deposited polyethylene terephthalate film (aluminum vapor-deposited layer thickness 400 mm, film thickness 110 μm) was used as the airtight layer.

Comparative Example 1
In the said Example 1, the duct was manufactured by the same method as Example 1 except not giving a boric-acid type flame retardant to the urethane foam used as a heat insulation layer.

Comparative Example 2
In Example 1 above, as the core material, a stainless steel core material is used, spirally wound from above the non-woven fabric, and bonded using an adhesive, and further, an aluminum foil laminated glass fiber as a heat insulating layer and an airtight layer. A duct was manufactured in the same manner as in Example 1, except that a fabric was bonded to a glass wool layer {Magwool AG2425 (Mag), thickness 25 mm, density 24 kg / m ³ }.

Example 6
In the said Example 1, as a flame retardant used for a heat insulation layer, a halogenated flame retardant and antimony trioxide {(product name) STOX-W-16 made by Nippon Seiko Co., Ltd.} are used, and the solid content adhesion amount is 0. A duct was manufactured in the same manner as in Example 1 except that the amount was 0.05 g / cm ² .

  From each of the ducts obtained in Examples 1 to 6 and Comparative Examples 1 to 3, 10 cm long ducts were cut out, spread out, 10 cm × 10 cm test pieces were prepared, and contacted with a heat source at 800 ° C. While heating, a spark (ignition source) was placed on the top of the test piece. The heating time was 20 minutes, and the amount of heat generated during that time was measured. When the test piece ignited, the time required for ignition and the time required for extinction were measured. Moreover, the state of the heat insulation layer after heating for 20 minutes was observed. The measurement results are shown in Table 1.

  The ducts obtained in Examples 1 to 6 and Comparative Examples 1 to 3 were cut at the construction site, and the ease of cutability and workability were examined. Also, the duct was leveled in a straight pipe state, air was passed through the duct using an air flow generator, the differential pressure of the measuring pipe was measured, and the pipe frictional resistance coefficient was calculated. Table 2 shows the measurement results.

  Table 1 shows a 10 cm x 10 cm test piece prepared from the duct, and the amount of heat generated and the time required for ignition when the sample was heated with a heat source of 800 ° C using a heat generation tester (cone calorimeter) were examined. It is a result. A spark (ignition source) is installed on the test piece. If a combustible gas is generated from the test piece during heating, the test piece is ignited.

Examples 1 to 6 and Comparative Examples 3 to 4 indicate that the test piece did not ignite and the calorific value was lower than 8.0 MJ / m ² , which cleared the incombustibility certification test approved by the Ministry of Land, Infrastructure, Transport and Tourism ( (If the calorific value is 8.0 MJ / m ² or more, it becomes NG in the non-flammability certification test). However, Comparative Example 1 indicates that the urethane foam, which is a heat insulating layer, is not flame retardant, so that it ignites from the heat insulating layer and does not pass the non-flammability certification test, and Example 6 does not ignite and generates heat. Although the amount is 8.0 MJ / m ² or less and clears the nonflammability certification test, the heat insulating layer after 20 minutes of overheating is slightly broken, indicating that it is not always satisfactory.

  As a nonflammable or flame-retardant heat insulating resin duct, it is effective to use a heat insulating material using a boric acid flame retardant for the heat insulating layer. The boric acid chemical forms a glass layer when heated, and the formation of the glass layer maintains the shape of the heat insulating layer after overheating. Moreover, the magnesium hydroxide added to the core material causes an endothermic reaction when overheated. The incombustible or flame-retardant heat insulating resin duct of the present invention can effectively suppress the combustion of the duct by a chain reaction between the formation of the glass layer of the heat insulating layer and the endothermic reaction of the core material.

  Table 2 shows the results of judging whether it can be cut quickly and easily using a non-flammable or flame-retardant insulating resin duct at the construction site, and the non-flammable or flame-retardant insulating resin duct in a straight tube Installed and generated the flow of wind inside the duct with an air flow generator, measured the difference in static pressure at the measurement length, and calculated the straight pipe pipe friction resistance coefficient from the air flow and the differential pressure at that time Yes.

  Examples 1 to 6 and Comparative Example 1 are excellent in duct cutting workability in the field because they use a thermoplastic hard resin or a material containing a flame retardant based on a thermoplastic hard resin as a reinforcing core material. However, since Comparative Example 2 uses metal for the reinforcing core material, it is inferior in duct cutting workability, and since glass wool is used for the heat insulation layer, glass wool is scattered at the time of cutting, and safety and health of work It is inferior to.

Moreover, since Examples 1-6 and Comparative Example 1 have a smooth duct interior, the straight pipe portion pipe frictional resistance coefficient is a relatively low numerical value, but Comparative Example 2 uses a metal core. The inside of the duct is not smooth, and the straight pipe portion has a high coefficient of friction resistance.

Side view including a partial cross section of an example of the heat insulating resin duct of the present invention The side view including a partial cross section which shows an example of the pipe in a duct of the present invention

Explanation of symbols

1: Heat insulation layer 2: Airtight sheet 3: Inner tube nonwoven fabric 4: Reinforcement core material

Claims (7)

In an air-conditioning flexible duct in which a meat part made of nonwoven fabric and an inner tube made of a ring-shaped or spiral core material made of a thermoplastic hard resin, a heat insulating layer laminated thereon, and an airtight layer laminated thereon A non-flammable or flame-retardant heat-insulating resin duct using a flame-retardant treated resin foam layer or a flame-retardant treated thermoplastic fiber layer as the heat-insulating layer. The non-flammable or flame-retardant heat-insulating resin duct according to claim 1, wherein a non-woven fabric subjected to a flame-retardant treatment is used as the non-woven fabric of the inner tube. The incombustible or incombustible heat-insulating resin duct according to claim 1 or 2, wherein the airtight layer is a glass fiber fabric or a flame-retardant resin film laminated with a metal foil. The non-flammable or flame-retardant heat-insulating resin duct according to any one of claims 1 to 3, wherein the flame retardant imparted to the heat-insulating layer is a boric acid-based flame retardant. The non-flammable or flame-retardant heat insulating resin duct according to any one of claims 1 to 4, wherein a non-woven fabric constituting the inner tube is impregnated with a boric acid flame retardant. The incombustible or incombustible heat-insulating resin duct according to any one of claims 1 to 5, wherein the core material is made of aluminum hydroxide or a thermoplastic resin containing magnesium hydroxide. The flame retardant used in the core material is aluminum hydroxide or magnesium hydroxide, and the flame retardant used in the heat insulating layer is a boric acid-based flame retardant. Or flame-retardant insulation resin duct.

Images