JPH0890704A - Composite pipe - Google Patents

Abstract

PURPOSE: To obtain excellent heat insulating properties and sound insulating properties without generating a non-foamed part, in a composite pipe wherein an inner layer composed of a thermoplastic resin and an outer layer composed of a rigid material are integrated through an intermediate foamed resin layer, by forming the foamed resin layer from phenol resin foam. CONSTITUTION: A composite pipe 1 is constituted of an inner layer 11, a foamed resin layer 12 and an outer layer 13. The inner layer 11 is formed from a thermoplastic resin pipe composed of polyvinyl chloride or the like and the outer layer 13 is formed from fiber reinforced plastic and the foamed resin layer 12 is formed from a foamed phenol resin. Since the foamed resin layer 12 is formed from the foamed phenol resin, a non-foamed component does not remain in the foamed resin layer 12 like a urethane resin and the inner and outer layers 11, 13 are integrated through the foamed resin layer 12. Therefore, it is eliminated that the inner and outer layers 11, 13 are peeled during use and a heat or sound insulation defect is generated.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to composite tubes.

[0002]

2. Description of the Related Art Conventionally, a thermoplastic resin pipe which is an inner layer such as a vinyl chloride pipe and a thermoplastic resin pipe which surrounds the thermoplastic resin pipe have been provided as a pipe suitable for flowing a fluid of a drainage pipe or a wastewater pipe. A composite pipe having a three-layer structure in which a metal pipe such as a steel pipe serving as an outer layer is integrated via a foamed resin layer provided in the middle of the thermoplastic resin pipe and the metal pipe is used (Japanese Patent Laid-Open No. Hei 3).
No. 234991).

That is, this type of composite pipe is excellent in corrosion resistance because the inner layer which is in direct contact with drainage water and dirty water is formed of a thermoplastic resin. Moreover, since the outer layer is made of a metal tube and has rigidity, the tube itself is not damaged even when an impact is applied from the outside, and not only is it excellent in strength, but also a foamed resin is provided between the outer layer and the inner layer. Since the layers are provided,
It also has excellent sound insulation and heat insulation.

[0004]

By the way, in the above-mentioned conventional composite pipe, the foamed resin layer is formed of the urethane resin foam, but in the conventionally used urethane resin,
Since the unfoamed resin remains in the foamed resin layer, the thermoplastic resin tube that is the inner layer and the metal tube that is the outer layer are separated,
May cause poor insulation or sound insulation.

That is, in the case of the conventional urethane resin, the isocyanate contained in the component reacts with water to generate carbon dioxide gas, but when the escape of this carbon dioxide gas is insufficient, an unfoamed resin layer is formed. It is also said that the unfoamed resin layer is also formed when vinyl chloride enters the urethane layer. In view of such circumstances, it is an object of the present invention to provide a composite pipe of good quality with no unfoamed portion in the foamed resin layer.

[0006]

In order to achieve such an object, a composite pipe according to the present invention has a foamed resin layer in which an inner layer made of a thermoplastic resin and an outer layer made of a rigid material are provided in the middle. In the composite pipe integrated via the above, the foamed resin layer is formed of a phenolic resin foam.

In the above construction, the inner layer is not particularly limited, but it is preferable to use a thermoplastic resin tube such as vinyl chloride or polypropylene. Examples of the phenol resin forming the foamed resin layer include novolac type phenol resin. The thickness of the foamed resin layer is not particularly limited, but is preferably about 0.5 to 1.5 mm. The expansion ratio of the phenolic resin forming the foamed resin layer is preferably about 2 to 5 times.

The outer layer may be made of metal, FRP (fiber reinforced plastic) or the like, but FRP is preferable if it is desired to reduce the weight of the composite pipe. In the case of the FRP outer layer, the thickness of the FRP layer is preferably about 1.0 to 3.0 mm. The FRP outer layer can be manufactured by forming a foamed resin layer on the inner layer and then winding the prepreg on the foamed resin layer by a filament winding (FW) method or manually winding a sheet-shaped prepreg. Examples include a method of turning.

The prepreg is wound by stacking a prepreg having a thickness of about 1/10 of the thickness of the FRP layer to be obtained, rather than winding only one prepreg having the same thickness as the FRP layer to be obtained. It is preferable to do so. F
As the fiber constituting the RP layer, glass fiber is usually used, but carbon fiber, vinylon fiber, aramid fiber and the like can also be used.

Epoxy resin, polyester resin and the like are generally used as the resin constituting the FRP layer. The thickness of the primer layer is preferably 20 μm or less. That is, if it exceeds 20 μm, peeling may occur in the primer layer. Further, when the outer layer is made of metal, it is preferable to use a metal pipe such as a steel pipe or a stainless steel pipe.

[0011]

According to the structure of the composite pipe of the present invention, since the phenol resin has a simpler composition than the urethane resin, the foamed resin layer is formed without forming an unfoamed resin layer in the foamed resin layer. .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings showing the embodiments thereof. FIG. 1 shows an embodiment of a composite pipe according to the present invention. As shown in the figure,
The composite pipe 1 includes an inner layer 11, a foamed resin layer 12, and an outer layer 13.
It consists of and.

The inner layer 11 is formed of a vinyl chloride pipe, the outer layer 13 is formed of FRP, and the foamed resin layer 1 is formed.
2 is formed of foamed phenolic resin. A primer layer 14 is provided between the vinyl chloride pipe of the inner layer 11 and the foamed resin layer 12. According to this composite pipe 1, since the foamed resin layer 12 is formed of the foamed phenolic resin, an unfoamed portion does not remain in the foamed resin layer 12 like the urethane resin, and the inner layer 11 and the outer layer 13 have the foamed resin. It is firmly integrated via the layer 12.

Therefore, the inner layer 11 and the outer layer 13 are in use during use.
There will be no peeling off, and poor insulation and sound insulation. Further, since the outer layer 13 is formed by FRP, it is possible to reduce the weight as compared with a pipe using a metal pipe as the outer layer. Hereinafter, more specific examples will be described.

Example 1 As shown in FIG. 2 (a), a vinyl chloride pipe (Eslon pipe manufactured by Sekisui Chemical Co., Ltd.) 2 having a diameter of 50 A, which is the inner layer 11, was put on a commercially available primer for PVC (NO manufactured by Cemedine Co., Ltd.). .80) 3 was applied, and then the primer layer 14 adjusted to a thickness of 10 μm by the thickness adjusting means 4 having an ironing structure was formed.

As shown in FIG. 2 (b), an aqueous unfoamed phenolic resin 5 having the following composition is applied to the surface of the primer layer 14 in the same manner as the primer, and the thickness adjusting means 4 having an ironing structure 0.3 is applied. The thickness was adjusted to 0.4 mm and the foamed resin layer 12 made of phenol resin having a thickness of 1 mm was formed by heating with hot air at 130 to 180 ° C. for 1 to 2 minutes.

Next, as shown in FIG. 2B, the width 160
mm, thickness 0.2 mm, epoxy resin impregnated prepreg 6 was wound simultaneously from 10 positions (only two positions are shown in the figure) with a phase shift of 36 ° to form a prepreg layer having a thickness of 2 mm. Then, the prepreg 6 is cured by heating and drying in a heating and drying oven (not shown), and FR
A composite pipe 1 as shown in FIG. 1 having a P layer as an outer layer 13.
I got

[Blend of phenolic resin] 100 parts by weight of phenol containing novolac type catalyst (Selfen TD-2031 manufactured by DIC) styrene-acrylic copolymer resin (Polysol AP-3700 manufactured by Showa High Polymer Co., Ltd.) 5-30 parts by weight Water 10- 50 parts by weight (however, the viscosity was adjusted to 3000 to 5000 cps by mixing water) The composite tube 1 obtained as described above had a specific gravity of 1.5 to 2.
0 to 70 to 7 compared with a composite pipe using a conventional metal pipe as an outer layer
It was about 5% lighter. Further, when the foamed phenol resin layer as the foamed resin layer 12 was cut open and the foaming state was confirmed, there was no unfoamed layer.

Example 2 Example 1 was repeated except that a solvent-based resin having the following composition was used as the phenol resin, and the resin was applied to a vinyl chloride tube, air-dried and then foamed by drying at 100 to 130 ° for about 1 minute. In the same manner as above, the composite pipe 1 as shown in FIG.
I got [Phenolic Resin Blend] Novolak type catalyst-containing phenol (DIC's Serfen TD-2031) 100 parts by weight Solvent (methyl ethyl ketone: methanol = 5-10: 1) 100-300 parts by weight Viscosity 1000-2000 cps Obtained as above The composite pipe 1 has a specific gravity of 1.5 to 2.
0 to 70 to 7 compared with a composite pipe using a conventional metal pipe as an outer layer
It was about 5% lighter. Further, when the foamed phenol resin layer as the foamed resin layer 12 was cut open and the foaming state was confirmed, there was no unfoamed layer.

(Example 3) Example 1 was repeated except that a solvent-based resin having the following composition was used as the phenol resin, the solution was applied to a vinyl chloride tube, air-dried, and then foamed by drying at 100 to 130 ° for about 1 minute. In the same manner as above, the composite pipe 1 as shown in FIG.
I got [Phenolic Resin Mixture] Novolak-type catalyst-containing phenol (DIC's Serfen TD-2031) 100 parts by weight Solvent (methyl ethyl ketone: methanol = 5-10: 1) 50-100 parts by weight Viscosity 5000-10000cps Obtained as above The composite pipe 1 has a specific gravity of 1.5 to 2.
0 to 70 to 7 compared with a composite pipe using a conventional metal pipe as an outer layer
It was about 5% lighter. Further, when the foamed phenol resin layer as the foamed resin layer 12 was cut open and the foaming state was confirmed, there was no unfoamed layer.

The composite pipe according to the present invention is not limited to the above embodiment. For example, in the above-described embodiment, the strip-shaped prepreg 6 is wound at 10 positions at the same time by shifting the phase by 36 ° to form a prepreg layer having a thickness of 2 mm. However, the prepregs 6 are sequentially wound one by one. Alternatively, 10 sheet-like prepregs having the same length as the vinyl chloride pipe 2 and substantially the same width as the circumference of the vinyl chloride pipe 2 and a thickness of 0.2 mm are prepared, and this prepreg is used as the foamed resin layer 12. The FRP layer serving as the outer layer 13 may be formed by sequentially overlapping and winding the foamed resin layer on the foamed resin layer so that the foamed resin layer becomes a tubular body along the vinyl chloride pipe 2 formed on the surface. .

Further, in the above embodiment, when the primer and the foamed phenol resin were applied, they were dropped from above, but they may be applied by spraying from the surroundings. Further, in the above-mentioned embodiment, the inner surface of the vinyl chloride pipe 2 serving as the inner layer is smooth, but it may be provided with a spiral rib inclined at a desired angle with respect to the pipe axis.

[0023]

As described above, in the composite pipe according to the present invention, since the foamed resin layer serving as the intermediate layer is formed of the foamed phenolic resin, the unfoamed portion is more likely to be formed than in the case where the conventional urethane foamed resin is used. It has excellent heat insulation and sound insulation.

[Brief description of drawings]

FIG. 1 is a partially cutaway sectional perspective view showing one embodiment of a composite pipe according to the present invention.

FIG. 2 is an explanatory view showing a method of manufacturing a composite pipe according to the present invention in the order of steps.

[Explanation of symbols]

 1 Composite pipe 11 Inner layer 12 Middle layer 13 Outer layer

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Claims (1)

[Claims] 1. In a composite pipe in which an inner layer made of a thermoplastic resin and an outer layer made of a rigid material are integrated via a foamed resin layer provided in the middle, the foamed resin layer is formed of a phenol resin foam. A composite pipe characterized in that