JP2012219929A - Manufacturing method of fire resistant two-layer pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method capable of easily and inexpensively obtaining a fire resistant two-layer pipe with a mortar outer layer with high roundness in a radial cross section of the pipe, and hardly causing exfoliation or detachment of mortar of the outer layer.SOLUTION: The fire resistant two-layer pipe is manufactured by going through: a process of winding nonwoven fabric or open-cell foam around an outer peripheral surface of a synthetic resin pipe; a process of impregnating mortar into the nonwoven fiber or the open-cell foam; a process of covering a mesh sheet having flexibility and air permeability on an outer surface of the mortar; and a process of hardening/drying the mortar.

Description

  The present invention relates to a method for producing a fire-resistant double-layer pipe that can be used for piping such as a drain pipe based on the Building Standard Law or the Fire Service Law in high-rise or low-rise houses or buildings.

  Conventionally, in apartment houses such as apartments, condominiums, and office buildings, the outer peripheral surface of synthetic resin pipes such as polyvinyl chloride resin for water supply and drainage or as piping for supplying electricity, gas, etc. A fire-resistant two-layer pipe coated with a fire-resistant material such as mortar is used. This fire-resistant double-layer pipe can prevent the spread of fire through the above synthetic resin pipes arranged between adjacent sections in an apartment building in the event of a fire, and is based on the Building Standard Law and the Fire Service Law. Necessary structures and performance are defined in standards and administrative guidance.

  In the fireproof two-layer pipe, in order to improve fire resistance, soundproofing, heat insulation, etc., the covering material has been improved. For example, an outer layer of refractory material such as mortar is made of inorganic material such as glass wool. It has been proposed to produce a fire-resistant two-layer pipe by mixing fibers or forming the inorganic fiber layer between a synthetic resin pipe of the inner pipe and a mortar covering the outer peripheral surface thereof.

  Specifically, in Patent Document 1, fiber mortar or the like in which glass wool or the like is mixed with cement is discharged into the gap between the outer peripheral surface of the synthetic resin pipe and the mold, and the synthetic resin pipe is made of a refractory material. A manufacturing method by extrusion molding to coat is described.

  Further, in Patent Document 2, glass wool or the like is placed on an endless felt, and one layer of the glass wool is wound around a metal core tube disposed in contact with the endless felt. The resulting mortar film is wound up to a predetermined thickness, cured and cured, and then the metal core tube is pulled out to integrally form the mortar outer tube and glass wool, etc., and the inner tube inside the obtained integral molded body Or a method of integrally forming a mortar outer tube, glass wool and the inner tube through the same process using an inner tube instead of the metal core tube, etc. Proposed.

  Furthermore, in Patent Document 3, a nonwoven fabric is wound around the outer surface of a synthetic resin tube, and then impregnated with mortar to thereby provide a sound absorbing layer of the nonwoven fabric and a soundproofing layer in which the nonwoven fabric is impregnated with mortar. It is described to produce a refractory double-layer tube having

JP 2002-1712 A JP 2008-249028 A JP 2011-21617 A

However, the manufacturing method by the above-described extrusion molding, the viscosity of the refractory material discharged into the gap between the outer peripheral surface of the synthetic resin pipe and the mold, and the characteristics such as the type and viscosity of the refractory material, It is not easy to set the formulation and manufacturing conditions, such as requiring adjustment of the pressure and speed of extrusion.
In addition, since the refractory material discharged into the mold receives a force in the direction in which it is extruded and the direction of rotation of the screw of the extruder, the fiber component contained in the refractory material is oriented in a specific direction. Tend to. For this reason, it cannot be said that the strength characteristic with respect to cracking or peeling of the refractory material is necessarily sufficient.

On the other hand, in the method of winding the mortar film made as described above, the mortar film paper making apparatus is inferior in freedom of operation in the case of multi-product manufacturing, and the manufacturing cost increases.
Moreover, it is difficult to efficiently form a mortar film having a thickness of 3 mm or more by the papermaking method. In order to obtain a mortar layer having a predetermined thickness, the mortar film is laminated on the outside of the inner tube. I have to wind it up. Furthermore, the fiber component blended in the papermaking mortar is two-dimensionally oriented parallel to the film surface. Therefore, a step occurs in the mortar layer in the radial cross section of the tube at the beginning and end of winding, the roundness is poor, and the adhesive strength between the laminated mortars is not always sufficient, There is concern about the falling off of the coating.

  Furthermore, in the above-described method for impregnating the nonwoven fabric with mortar, the mortar impregnated layer is easily deformed so as to hang downward due to its own weight. It was difficult to get expensive.

  The present invention has been made in order to solve the above technical problem, and is a refractory double-layer pipe in which the inner pipe is a synthetic resin pipe, and the roundness of the outer mortar layer in the radial cross section of the pipe is high. An object of the present invention is to provide a method for producing a fire-resistant double-layer tube that can easily and inexpensively obtain a fire-resistant double-layer tube in which the mortar of the outer layer does not easily peel off or fall off.

The method for producing a fire-resistant double-layer pipe according to the first aspect of the present invention includes a step of winding a nonwoven fabric or open cell foam around the outer peripheral surface of a synthetic resin tube, and a stretch and aeration on the surface of the nonwoven fabric or open cell foam. And a step of covering the mesh sheet through which the mortar can pass, a step of impregnating the non-woven fabric or open-cell foam with the mortar through the mesh sheet, and a step of curing and drying the mortar. It is characterized by having.
According to such a manufacturing method, deformation of the mortar impregnated layer due to the mortar's own weight is suppressed by the stretching force of the mesh sheet, the roundness of the mortar impregnated layer in the radial cross section of the pipe is high, It is possible to obtain a fire-resistant double-layer tube that does not easily drop off at a low cost.
Here, the fireproof double-layered pipe as referred to in the present invention is not limited to a straight pipe but includes various shapes such as a pipe having a branch such as a curved pipe, a Y-shaped pipe, and a T-shaped pipe, and a joint.

In addition, the method for producing a fireproof two-layer pipe according to the second aspect of the present invention includes a step of winding a nonwoven fabric or open cell foam around the outer peripheral surface of a synthetic resin tube, and a step of impregnating the non-woven fabric or open cell foam with mortar. And a step of covering the outer surface of the mortar with a mesh sheet having stretchability and air permeability, and a step of curing and drying the mortar.
Also by such a method, the same effect as the manufacturing method according to the first aspect can be obtained.

Furthermore, the method for producing a fireproof double-layered pipe according to the third aspect of the present invention includes a step of impregnating a non-woven fabric or open-cell foam with mortar, and a non-woven fabric or open-cell foam impregnated with the mortar. A step of winding around the outer peripheral surface, a step of covering the outer surface of the mortar on the outer peripheral surface of the synthetic resin pipe with a mesh sheet having stretchability and air permeability, and a step of curing and drying the mortar. It is characterized by.
Even with such a manufacturing method, a fire-resistant double-layer pipe similar to the above can be preferably manufactured. This method is particularly suitable for bent pipes, pipes having branches such as Y-shaped pipes and T-shaped pipes, joints, etc. It can be suitably applied to a synthetic resin pipe having a complicated shape.

Moreover, the manufacturing method of the fireproof two-layer pipe | tube which concerns on the 4th aspect of this invention replaces with the said synthetic resin pipe | tube in the manufacturing method which concerns on either of the said 1st-3rd aspect, A metal core material is used, and after the mortar curing / drying step, the core material is extracted, and a synthetic resin pipe is inserted into the extracted portion.
Thus, if the core material is used instead of the synthetic resin pipe, the outer layer (refractory layer) by the mortar impregnated layer having a high roundness is obtained in the same process as the manufacturing method according to the first to third aspects. The inner pipe can be formed separately from the synthetic resin pipe, and the inner pipe and the outer layer can be integrated afterwards to produce a fireproof two-layer pipe.

The step of covering the mesh sheet is preferably performed by winding the mesh sheet and thermally welding the ends of the mesh sheet.
Thereby, a mesh sheet | seat can be simply fixed so that the synthetic resin pipe | tube which is a curved surface may be surrounded.

Further, the step of covering the mesh sheet is preferably performed by covering the mesh tube so as to surround the synthetic resin pipe or the core material using a mesh tube in which the mesh sheet is formed in a tube shape in advance. .
Also by such a method, the mesh sheet can be easily put on the outer surface of the synthetic resin pipe or core material, and the fitting property to the outer surface of the synthetic resin pipe or core material of various shapes can be improved. .

According to the method for producing a refractory double-layer pipe according to the present invention, a refractory double-layer pipe having a high roundness of a mortar outer layer in a radial cross section of the pipe and being less prone to peeling or dropping of the mortar of the outer layer can be easily and low-cost. Can be manufactured.
Therefore, the fireproof two-layer pipe obtained by the production method according to the present invention has a high roundness of the mortar part of the outer layer of the synthetic resin pipe, and is formed with a smooth surface in which unevenness of the outer layer surface is suppressed, It is excellent in impact resistance and fire resistance, and is suitable for piping such as drainage pipes for high-rise or low-rise houses or buildings.

It is a schematic sectional drawing of the fireproof two-layer pipe concerning this invention.

Hereinafter, the present invention will be described in detail with reference to the drawings.
In FIG. 1, the structure of the fireproof double layer pipe obtained by the manufacturing method which concerns on this invention is shown. This fireproof two-layer pipe 1 has a two-layer structure in which an inner pipe is a synthetic resin pipe 2 and an outer peripheral surface thereof is covered with a mortar impregnated layer 3 obtained by impregnating a nonwoven fabric or an open-cell foam with mortar. And the mortar impregnation layer 3 contains the mesh sheet | seat (not shown) in the part.

In the method for producing a fireproof two-layer pipe according to the first aspect of the present invention, the step of winding a nonwoven fabric or open cell foam around the outer peripheral surface of the synthetic resin tube, and the surface of the nonwoven fabric or open cell foam have stretch properties and A step of covering a mesh sheet having air permeability and allowing mortar to pass through; a step of impregnating the non-woven fabric or open-cell foam through the mesh sheet; and a step of curing and drying the mortar. And go through.
By passing through such a process, the entire fire-resistant two-layer pipe is integrated by the stretching force of the mesh sheet, so deformation of the mortar impregnated layer due to the mortar's own weight is suppressed, and the pipe radial direction is easy and low cost. The mortar impregnation layer in the cross section can be formed with high roundness.
In addition, the above manufacturing method is not limited to the case where the synthetic resin pipe is a straight pipe, and is suitable also in the case of a complicated shape such as a pipe having a branch, such as a curved pipe, a Y-shaped pipe, or a T-shaped pipe, or a joint. Can be applied.

Mortar-impregnated layers impregnated with nonwoven fabric or open-cell foam are inferior in shape retention, and if left standing for curing and drying, the mortar-impregnated layer hangs down by its own weight depending on the weight and viscosity of the mortar. Or deform. For this reason, in the case of a pipe having a circular cross section, the outer peripheral cross section of the mortar impregnation layer in the radial direction of the pipe may not be a perfect circle, and the difference in thickness depending on the position of the mortar impregnation layer may be large.
In the present invention, the outer surface of the nonwoven fabric or the open cell foam is covered with a mesh sheet having stretchability and breathability, and then the nonwoven fabric or the open cell foam is impregnated with mortar. It is possible to suppress deformation due to its own weight, maintain its shape, and prevent the roundness of the mortar impregnated layer from deteriorating. Moreover, the reinforcement effect which prevents peeling and dropping-off of a mortar impregnation layer is also acquired.

Moreover, since the said mesh sheet is covered with the mortar impregnated with the nonwoven fabric or the open-cell foam, it can be made to adhere to the nonwoven fabric or the open-cell foam surface without using an adhesive or an adhesive.
Thus, since the said mesh sheet is used so that it may cover the outer side of a pipe | tube and it may be made to contact | adhere to a nonwoven fabric or an open cell foam, what has a stretching property is used suitably.

In addition, after the mesh sheet is put on the surface of the non-woven fabric or open cell foam, the inner non-woven fabric or open cell foam is impregnated with mortar. It is.
Furthermore, when the mortar is cured and dried, the mesh sheet is a mesh having a size sufficient to evaporate moisture, volatile components, and the like in the mortar from the surface of the mesh sheet, and has air permeability. is required.

The material of the mesh sheet is not particularly limited as long as it is a material that can be stretched. For example, polyethylene terephthalate-based (PET-based polyester), polyamide (6-nylon, 6,6-nylon, etc.), acrylic-based, vinylon, polyolefin-based synthetic resin or rubber, or the above synthetic resin Alternatively, it may be formed by weaving natural fibers such as rubber fibers, cotton or wool.
However, since the mesh sheet is an auxiliary material used for the purpose of supporting and reinforcing the mortar impregnated layer, the thickness is preferably thin.

Among the above materials, Netron (registered trademark), which is made of synthetic resin such as high-density polyethylene, polypropylene, ethylene-vinyl acetate copolymer (EVA), low-density polyethylene, etc., and has a mesh formed by mold extrusion molding, Since there is no collapse and the intersection does not shift or peel off, it is preferably used.
Also, if a mesh sheet made of such a thermoplastic resin is used, the end of the mesh sheet is wound around the surface of the nonwoven fabric or open cell foam on the outer peripheral surface of the synthetic resin pipe, which is a curved surface, and then heat-sealed. By this, it can fix so that the said synthetic resin pipe | tube may be surrounded, and the operation | work in the process which covers a mesh sheet | seat becomes easy.

The mesh sheet is preferably formed in a tube shape in advance.
In this way, the mesh sheet is tube-shaped, so that it is surrounded by equal pressure on the tube without being twisted or superimposed, compared to the case of winding a planar mesh-shaped sheet. Can be covered. And since it has elasticity, it can hold down and support a nonwoven fabric or open-cell foam firmly, can also prevent shifting | deviating, and is excellent in the fitting property with respect to the outer shape of a pipe | tube. For this reason, it becomes possible to form the surface of the mortar impregnated layer with a smoother surface.

Further, in the production method according to the second aspect of the present invention, a step of winding a nonwoven fabric or open cell foam around the outer peripheral surface of the synthetic resin pipe, a step of impregnating the nonwoven fabric or open cell foam with mortar, and the mortar The outer surface is covered with a stretchable and breathable mesh sheet and the mortar is cured and dried.
In the production method according to the second aspect, the order of the step of impregnating the nonwoven fabric or the open cell foam with mortar and the step of covering the mesh sheet is opposite to the production method according to the first aspect, but the mesh The sheet is an auxiliary material for the mortar-impregnated layer. Even when the sheet is covered after impregnation with the mortar, the same effect as in the manufacturing method according to the first aspect can be obtained.
Also in this case, the mesh sheet can be adhered to the mortar surface without using an adhesive or a pressure-sensitive adhesive by covering the mortar impregnated with the nonwoven fabric or the open-cell foam before curing.

  The mesh sheet used in the manufacturing method according to the second aspect can be of the same material and form as those used in the first manufacturing method. However, in the production method according to the second aspect, since the nonwoven sheet or the open cell foam is impregnated with mortar and then the outer surface of the mortar is covered with the mesh sheet, the mesh having a size through which the mortar can pass is not necessarily provided. You don't have to.

In the manufacturing method according to the third aspect of the present invention, the step of impregnating the nonwoven fabric or the open cell foam with mortar, and the nonwoven fabric or the open cell foam impregnated with the mortar are wound around the outer peripheral surface of the synthetic resin pipe. A process, a process of covering the outer surface of the mortar on the outer peripheral surface of the synthetic resin pipe with a mesh sheet having stretchability and air permeability, and a process of curing and drying the mortar.
As described above, a non-woven fabric or an open cell foam impregnated with mortar may be formed separately from the synthetic resin pipe, and then wound around the outer peripheral surface of the synthetic resin pipe. Before the mortar is cured, the nonwoven fabric or the open cell foam impregnated with the mortar is wound around the outer peripheral surface of the synthetic resin tube, and the mesh sheet is put over the seam so that the adhesive or pressure-sensitive adhesive is covered. Without using it, the seam of the nonwoven fabric or the open cell foam can be adhered, and the mortar impregnation layer can be tightly fixed to the outer peripheral surface of the synthetic resin pipe. Moreover, like the manufacturing method according to the first aspect, the roundness of the mortar-impregnated layer can be increased, and peeling and dropping are also suppressed.
This manufacturing method is particularly suitable for obtaining a fireproof double-layer pipe having a complicated shape such as a bent pipe, a pipe having a branch such as a Y-shaped pipe or a T-shaped pipe, and a joint.
Note that the mesh sheet used in the manufacturing method according to the third aspect can also be of the same material and form as those used in the first and second manufacturing methods.

In the present invention, the material of the synthetic resin pipe, which is the inner pipe, is not particularly limited, and the same material as a conventional fire-resistant double-layer pipe can be used. For example, a tubular body made of a thermoplastic resin such as a rigid polyvinyl chloride pipe (PVC pipe), a polyethylene terephthalate pipe (PET pipe), or a polypropylene pipe (PP pipe) can be used.
The shape of the synthetic resin pipe is not particularly limited, and may be any of a straight pipe, a bent pipe, a pipe having a branch such as a Y-shaped pipe, a T-shaped pipe, and a joint.

A manufacturing method according to a fourth aspect of the present invention is the manufacturing method according to any one of the first to third aspects, wherein the synthetic resin pipe or the metal core material is used instead of the synthetic resin pipe. Is used. And after the hardening / drying step of the mortar in the manufacturing method according to any of the first to third aspects, the core material is drawn out, and a synthetic resin pipe is inserted into the drawn-out portion, thereby providing fire resistance. A two-layer tube is obtained.
Thus, after winding the nonwoven fabric or the open-cell foam on the core material, the outer layer (fireproof layer) by the mortar impregnated layer is formed on the inner tube through the same steps as the manufacturing method according to the first to third aspects. It can be formed separately from the synthetic resin pipe, and the fireproof two-layer pipe can be manufactured by integrating the inner pipe and the outer layer later.

The core material used here is made of synthetic resin or metal, and has the same outer peripheral shape as the synthetic resin pipe used as the inner pipe. Moreover, this core material needs to be a shape which can be pulled out from the mortar impregnation layer used as an outer layer after the mortar hardening and drying process.
For this reason, the manufacturing method which concerns on a 4th aspect is a method suitable for manufacture of a straight tubular fireproof two-layer pipe.

The non-woven fabric or open-cell foam wound around the outer peripheral surface of the synthetic resin tube or core is a base material for the mortar impregnated layer, thereby forming an outer layer excellent in impact resistance and fire resistance. it can.
In the nonwoven fabric, since fibers are randomly oriented, mortar can be uniformly dispersed and impregnated, and the strength against tension and bending is three-dimensionally uniform. Similarly, open-cell foam can also be impregnated with mortar dispersed evenly in open-cell.

When using a nonwoven fabric, a compressed body of organic or inorganic fibers or needle punched felt is preferable.
The material of the nonwoven fabric fiber may be either an organic fiber or an inorganic fiber. Examples of the organic fibers include polyethylene terephthalate (PET polyester), polyamide (6-nylon, 6,6-nylon, etc.), acrylic, vinylon, polyolefin, cotton, wool, and the like. Examples of the inorganic fiber include glass fiber, rock wool, and ceramic fiber. Among these, from the viewpoint of fire resistance, inorganic fibers are preferable, but from the viewpoint of physical properties and price, and ease of handling such as being able to use commercially available products as they are, polyester, polypropylene, etc. Nonwoven fabrics made of synthetic fibers are preferred.

Since the thickness of the non-woven fabric or open-celled foam hardly varies even after the impregnated mortar is cured, one having a desired thickness may be prepared and wound in advance. Therefore, it is possible to easily adjust the mortar thickness of the outer layer of the fireproof double-layer tube.
The non-woven fabric or open-cell foam may be a planar sheet shape or may be three-dimensionally molded in advance according to the shape of the synthetic resin tube of the inner tube.
Moreover, the said nonwoven fabric or open-celled foam is good also as two or more layers by overlapping, or also overlapping the thing from which a density and material differ.

  The thickness of the non-woven fabric can be appropriately determined according to the material, the purpose of use of the fireproof double-layer tube, the use location, etc. In the case of a single layer, it is usually 3 to 30 mm, preferably 5 to 10 mm. is there. In the case of multiple layers, it is generally thicker than in the case of a single layer, but from the viewpoint of soundproofing effect, cost, etc., the increase in thickness may be about 2 to 15 mm compared to the case of a single layer. preferable.

  Moreover, as an open cell foam, a foaming urethane foam etc. can be used, for example, and it can be used by the thickness substantially the same as the said nonwoven fabric. However, the open cell foam generally has a smaller reinforcing effect on the mortar impregnated layer than the nonwoven fabric.

The mortar used in the present invention is preferably a cement-based mortar from the viewpoint of strength and density after curing, fire resistance, and the like. For example, various Portland cements such as normal, early strength, moderately hot, and very early strength, or blast furnace cement obtained by mixing fly ash, blast furnace slag, and the like with these. These mortars can impart good workability by selecting a water cement ratio.
The viscosity of the mortar to be used needs to be determined in consideration of the material of the nonwoven fabric or open-cell foam, the surface density, the thickness, the mortar impregnation speed and the curing time.

  The cured mortar preferably has a high strength. However, by impregnating the nonwoven fabric or the open-cell foam with the mortar, the strength of the mortar-impregnated layer can be improved. There is no need to use mortar. Rather, since the permeability to the nonwoven fabric or the open-cell foam deteriorates, it is better not to contain fibers.

  The thickness of the mortar-impregnated layer can be appropriately determined according to the purpose of use and the location of use of the fireproof two-layer tube, but is preferably 3 mm or more from the viewpoint of fire resistance and strength. More preferably, it is about 5 to 10 mm. If the thickness is within such a range, the necessary fireproof performance can be sufficiently ensured. If it is thicker than this, the weight of the refractory double-layer pipe increases, which makes transportation and piping construction difficult, and increases the cost.

The mortar may be impregnated over the entire thickness of the non-woven fabric or open-cell foam, or alternatively, only the surface layer of the non-woven fabric or open-cell foam is impregnated and the portion in contact with the synthetic resin pipe is not impregnated with mortar. The non-woven fabric or open cell foam may remain, that is, a mortar impregnated layer and a mortar non-impregnated layer may be formed.
When a non-woven fabric or open-cell foam is wound around a core material, the mortar impregnated with the non-woven fabric or open-cell foam may shrink when cured, and the core material may be held firmly and difficult to come off. . At this time, if the core material is forcibly pulled out, the mortar layer may break.
On the other hand, when the two-layer structure of the mortar impregnated layer and the mortar non-impregnated layer is used as described above, the mortar non-impregnated layer acts as a cushioning material, and the core material can be easily removed. It is done.

  As described above, since the mortar impregnated layer is a mortar layer reinforced with a nonwoven fabric or open cell foam, the fire resistance is equivalent to that of a conventional fiber-mixed mortar, and cracking due to external force is unlikely to occur. It is not. Therefore, the fireproof two-layer pipe obtained by the manufacturing method according to the present invention can be suitably used as a drainage pipe for a high-rise or low-rise house or building.

The method for impregnating the nonwoven fabric or the open-cell foam with mortar is not particularly limited, and can be performed by a method such as coating, pouring, spraying, or dipping.
In this way, after the mortar is uniformly impregnated into the entire nonwoven fabric or open cell foam, the outermost peripheral surface of the synthetic resin pipe or core is coated with the mortar impregnation layer by curing and drying the mortar. .
The conditions for curing and drying the mortar are appropriately determined according to the mortar, environment, etc. to be used. Usually, after curing until the initial strength is developed, the mortar is cured and dried.

  The refractory double-layered tube is a surface of the same or other types of mortar, resin film, woven fabric, non-woven fabric, paint, etc., depending on the purpose and place of use of the refractory double-layer tube. Covering with a coating material or the like is free.

EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not restrict | limited by the following Example.
[Example 1]
On the outer surface of a rigid polyvinyl chloride pipe (PVC pipe; VP100A) with a nominal diameter of 2 m in length, a PET felt (material PET; mainly 33 decitex, a mixture of several other fiber diameters, an approximate thickness of 6.5 mm The surface weight average 120 g / m ² ) was wound. This PET felt is covered with a polyethylene mesh tube (Netron (registered trademark)) to surround the outer surface of the PVC pipe, and mortar (main component Portland cement 70 ± 10 parts by weight, sand 26 ± 6 weights) is placed on the PET felt. (Impregnated under the conditions approved by the Minister of Land, Infrastructure, Transport and Tourism)). Then, after curing at 30 ° C. for 24 hours, the mortar-impregnated layer was formed by curing and drying by natural curing for 14 days, and a refractory double-layer tube was produced.

[Example 2]
In Example 1, a PET felt was impregnated with mortar and then covered with a mesh tube. Otherwise, a fireproof double-layer tube was produced in the same manner as in Example 1.

[Comparative Example 1]
In Example 1, after winding a polyester cold water bottle (ES3000; Toyobo Specialty Trading Co., Ltd.), mortar was impregnated. Otherwise, a fireproof double-layer tube was produced in the same manner as in Example 1.

[Comparative Example 2]
In Example 1, a fireproof double-layer tube was produced in the same manner as in Example 1 except that the mesh tube was not covered.

About the fireproof two-layer pipe obtained by the said Example and comparative example, the thickness and roundness in the radial direction cross section of the pipe | tube of a mortar impregnation layer were evaluated.
Roundness was evaluated by the difference between the maximum diameter and the minimum diameter in the same circular cross section in the radial direction of the tube.
Further, the adhesion between the mortar-impregnated layer and the mesh tube or the cold chill, and the outer surface state of the mortar-impregnated layer were visually observed.
These results are summarized in Table 1.
In Table 1, the evaluation of adhesion was made as follows: ○: no float, x: float depending on the presence or absence of the lifted state of the mesh tube or the cold chill. In addition, the surface condition was as follows: ◯: smooth (when the surface unevenness is about the mesh tube or cold chill mesh), ×: the surface unevenness is larger than the mesh tube or cold chill mesh.

  What was produced in the said Example 1, 2 was high in roundness, was excellent also in the adhesiveness of the mortar impregnation layer, and was able to form this surface with a smoother surface.

1 Fire-resistant double-layer pipe 2 Synthetic resin pipe 3 Mortar impregnated layer

Claims (6)

Winding the non-woven fabric or open cell foam around the outer peripheral surface of the synthetic resin pipe;
A step of covering the surface of the non-woven fabric or open-cell foam with a mesh sheet having stretchability and breathability and allowing mortar to pass through;
Impregnating the nonwoven fabric or open cell foam with mortar through the mesh sheet;
And a step of curing and drying the mortar. Winding the non-woven fabric or open cell foam around the outer peripheral surface of the synthetic resin pipe;
Impregnating the non-woven fabric or open cell foam with mortar;
Covering the outer surface of the mortar with a stretchable and breathable mesh sheet;
And a step of curing and drying the mortar. Impregnating a nonwoven or open cell foam with mortar;
Winding the nonwoven fabric or open cell foam impregnated with the mortar around the outer peripheral surface of a synthetic resin pipe; and
Covering the outer surface of the mortar on the outer peripheral surface of the synthetic resin pipe with a mesh sheet having stretchability and air permeability;
And a step of curing and drying the mortar.   Instead of the synthetic resin pipe, a synthetic resin or metal core material is used, and after the mortar curing / drying step, the core material is pulled out, and the synthetic resin pipe is inserted into the extracted portion. It has a process, The manufacturing method of the fireproof two-layer pipe of any one of Claims 1-3 characterized by the above-mentioned.   5. The fireproof double-layer pipe according to claim 1, wherein the step of covering the mesh sheet is performed by winding the mesh sheet and heat-welding an end portion of the mesh sheet. Production method.   The step of covering the mesh sheet is performed by covering the mesh tube so as to surround the synthetic resin pipe or the core material using a mesh tube in which the mesh sheet is formed in a tube shape in advance. The manufacturing method of the fireproof two-layer pipe | tube of any one of Claims 1-4 to do.

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