JPH09196275A - Bent pipe and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably maintain a bent form obtained by secondary molding. SOLUTION: This bent pipe is formed by bending the middle part of a pipe body made of an olefin resin such as a polyethylene resin. A reinforcing layer 3 made of a reaction injection molding material using a norbornene monomar such as dicyclopentadiene and a metathesis catalyst as main materials is formed by coating in the outer peripheral surface of a tube body 2 at least in a bent middle part 2a.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a bend pipe made of a resin used for a sewer pipe or the like.

[0002]

2. Description of the Related Art In general, resin pipes are used for pipes used for sewage pipes, etc. In recent years, the resin used as the material of the pipes has been resistant to acids and alkalis, A polyethylene resin having strong characteristics is used, and a conduit is formed by the polyethylene resin pipe.

[0003]

However, in the case of the pipe body made of the polyethylene resin described above, in the case of obtaining a bend pipe having a curved midway necessary for constructing a pipe passage, the straight pipe body is subjected to heat treatment or the like. Although it is obtained by curving at a desired angle by secondary molding, since the polyethylene resin that is the material is a crystalline resin, the initial shape before secondary molding,
That is, there is a drawback in restoring the original straight shape, that is, reliability of shape stability.

Particularly, when the pipe body including the bend pipe as described above is used in a vacuum sewer system in which a downward slope and an upward slope are combined to form a pipe line, the bend pipe bends at the starting point of the slope portion. Although a portion is used, the bending state changes due to the above-mentioned drawbacks, which causes a problem that the vacuum state in the pipeline becomes incomplete.

Therefore, in order to solve the above problems, it is an object of the present invention to provide a bend pipe capable of stably maintaining a curved shape obtained by secondary molding, and a manufacturing method thereof.

[0006]

[Means for Solving the Problems] Next, means for solving the above problems will be described with reference to the drawings corresponding to the embodiments. The bend pipe 1 of the present invention is a bend pipe in which a middle portion is curved by secondary molding of a tubular body made of an olefin resin, and the outer circumference of at least the curved middle portion 2a of the outer peripheral surface of the tubular body 2 is the outer circumference. It is characterized in that the surface is coated with a reinforcing layer 3 made of a reaction injection molding material containing a norbornene-based monomer and a metathesis catalyst as main materials.

The bend pipe 1 of the present invention is an S-shaped bend pipe obtained by butt-welding two bend pipes obtained by forming a tubular body made of an olefin resin by secondary molding to form a curved middle portion. The outer peripheral surface of at least the curved middle portion 2a of the outer peripheral surface of the tubular body 2 is coated with a reinforcing layer 3 made of a reaction injection molding material mainly composed of a norbornene-based monomer and a metathesis catalyst. .

In the S-shaped bend pipe 1, a norbornene-based monomer and a metathesis catalyst are used as main materials on the outer circumferential surface of the tubular body 2 between at least two curved intermediate portions 2a of the outer circumferential surface. A configuration in which the reinforcing layer 3 made of a reaction injection molding material is formed by coating may be used.

Further, in the method for manufacturing the bend pipe 1 of the present invention, after the pipe body made of an olefin resin is formed in a curved shape by secondary molding, the pipe body 2 is used as an inner mold to form the pipe body 2. Surrounded by an outer mold 4, a reaction injection molding material containing a norbornene-based monomer and a metathesis catalyst as a main material is supplied to a gap between the inner mold 4 and the outer mold 4 to cause reaction curing, and the outer periphery of the tube body 2. The surface is coated with the reinforcing layer 3 made of the reaction injection molding material.

Further, according to the method of manufacturing the bend pipe 1 of the present invention, a bend pipe in which the middle portion of the bend pipe is formed by secondary molding of a pipe body made of an olefin resin is formed, and two of the bend pipes are butt welded. After forming an S-shaped bend pipe, the pipe body 2 is surrounded by an outer mold 4 with the pipe body 2 as an inner mold, and a norbornene-based monomer is provided in a gap portion between the inner mold and the outer mold 4. A reaction injection molding material containing a metathesis catalyst as a main material is supplied and cured by reaction, and a reinforcing layer 3 made of the reaction injection molding material is formed on the outer peripheral surface of the tubular body 2.

From the above, it is possible to obtain a bend pipe 1 in which the characteristics of a reaction injection molding material mainly composed of a norbornene monomer and a metathesis catalyst are added to the characteristics of an olefin resin. Is a polyethylene resin and the norbornene-based monomer is dicyclopentadiene, the reinforcing layer 3 is formed by adding shape stability by dicyclopentadiene to a tube having resistance to acid and alkali and strong impact resistance. It is possible to obtain the bend pipe 1 having the bend pipe 1.

[0012]

1 is a schematic perspective view showing an embodiment of a bend pipe according to the present invention. This bend pipe 1
A straight tubular body 2 made of polyethylene resin as an olefin resin is subjected to secondary molding such as heat molding to curve the intermediate portion 2a to a desired angle. As shown in FIG. The reinforcing layer 3 is formed by coating the outer peripheral surface of the midway portion 2a with a reaction injection molding material containing dicyclopentadiene as a norbornene-based monomer and a metathesis catalyst as a main material in layers.

Next, the structure of the outer die 4 used in the method for manufacturing the bend pipe 1 will be described. This outer mold 4 is
As shown in FIG. 2, in the two-part configuration of the upper mold 4a and the lower mold 4b, the concave groove-shaped cavities 5 each having a curved middle portion are mounted so that the tubular body 2 having the curved middle portion 2a is mounted. Support grooves 6 are formed so as to face each other and have an inner diameter substantially equal to the outer diameter of the tubular body 2 at both ends of the cavity 5.

The inner diameter of the cavity 5 is larger than the outer diameter of the tube body 2, and there is an endless ring shape between the outer peripheral surface of the tube body 2 and the inner peripheral surface of the cavity 5 which is the inner peripheral surface of the outer mold 4. So that the gap is formed, the diameter is made larger than that of the pipe body 2 by a length substantially equal to the wall thickness of the pipe body 2, and the step portion between the cavity 5 and each support groove 6 has a seal. Each material 7 is attached.

Further, the outer mold 4 is provided with a gate connected to an external material supply device at a position not shown, and a reaction injection molding material mainly composed of a norbornene-based monomer such as dicyclopentadiene and a metathesis catalyst. Are fed into the cavity.

Next, a method of manufacturing the bend pipe 1 of the present invention using the above-mentioned outer mold 4 will be described. First, the tubular body 2 which is the base of the bend pipe 1 is a straight polyethylene resin tubular body obtained by extrusion molding or the like, and the straight tubular body is subjected to secondary molding such as heat molding to obtain a tubular body. The midway portion 2a is curved and formed at a desired angle.

Next, the curved tube body 2 is used as an inner mold,
In the outer die 4 which is divided into upper and lower halves, the curved portion of the tubular body intermediate portion 2a is made to correspond to the position of the cavity 5, that is, the curved portion is mounted so as to be surrounded, and the upper die 4a,
The lower mold 4b is connected and the cavity 5 is closed. At this time,
Both ends of the tubular body 2 are mounted in the support groove 6 of the outer die 4, and are sandwiched by the support groove 6.

Next, a reaction injection molding material containing a norbornene-based monomer such as dicyclopentadiene and a metathesis catalyst as main materials is supplied from a supply device (not shown) into the cavity 5 through a gate. The supplied reaction injection molding material is injected into the gap between the outer peripheral surface of the curved portion of the tubular body in the cavity 5 and the inner peripheral surface of the cavity 5, and covers the outer peripheral surface of the midway portion 2a of the tubular body 2. .

After the norbornene-based monomer is reacted and cured in the outer mold 4, the upper and lower molds 4a, 4b are formed.
Is released, and thus the bend pipe 1 described above is obtained. When the reaction injection molding material is injected into the outer mold 4 and heat-cured, it melts the polyethylene resin that is the material of the tubular body 2 that is the inner mold and firmly adheres to the polyethylene resin. The coating is formed integrally.

Therefore, according to the bend pipe 1 obtained by such a manufacturing method, the pipe body 2 made of polyethylene resin is used.
After curving at a desired angle, the outer peripheral surface of the curving portion is coated with a norbornene-based monomer such as dicyclopentadiene and a reaction injection molding material containing a metathesis catalyst as a main material to form a reinforcing layer 3. Because it did, the pipe body 2
A reaction injection molding material in which the shape instability after secondary molding, which is a drawback of polyethylene resin, which is a crystalline resin used as a material for Will stably maintain the shape obtained by the secondary molding, and as a result, the bend tube 1 will be provided with long-term stability of the shape. That is, it is possible to obtain the bend pipe 1 which has resistance to acids and alkalis of the polyethylene resin, and has impact-resistant characteristics and long-term excellent shape stability characteristics.

From the above, when the bend pipe 1 is used in a vacuum sewer system, even if the bend portion of the bend pipe 1 is used as the starting point of the slope portion, the bend of the bend pipe 1 due to change with time. The state does not change, the vacuum state inside the pipeline does not become incomplete, and a stable pipeline can be constructed.

In the above-described embodiment, the reaction injection molding material is coated only on the curved middle portion of the tubular body 2 to form the reinforcing layer 3. However, as shown in FIGS. 3 (a) and 3 (b), ,
The reinforcing layer 3 may be formed by coating on the outer peripheral surface of the entire tubular body 2.

Further, in the above-described embodiment, the example in which the tubular body 2 is formed in a substantially V shape in which the middle portion is curved is described. However, as shown in FIG. 4, the middle portion 2a is curvedly formed. The two end portions 2b of these pipes 2 are used.
It is also possible to connect them to each other to form an S-shape, and to cover the outer peripheral surface of the S-shaped tubular body 2 with the reinforcing layer 3.

In this case, first, as shown in FIG. 5, two tube bodies 2 having a curved intermediate portion 2a formed by secondary molding are
A hot plate 8 is brought into contact with each of the connected end portions 2b (see FIG. 5 (a)) to heat and melt, and the end portions 2b are pressure-bonded to each other for welding (see FIG. 5 (b)). They are connected by a construction method to form the S-shaped tubular body 2.

Then, the S-shaped tubular body 2 is used as an inner mold and is surrounded by an outer mold 4 in which an S-shaped cavity 5 is formed, as shown in FIG. ,
A reaction injection molding material containing a norbornene-based monomer and a metathesis catalyst as a main material is supplied to the gap between the inner mold (tube 2) and the outer mold 4 to cause reaction curing, and the outer peripheral surface of the tube 2 is covered. The reinforcing layer 3 is formed by coating with this reaction injection molding material (see FIG. 4).

Also in the case of this bend pipe 1, it is possible to obtain the same effect as that of the above-described embodiment, and the two pipe bodies 2 are provided.
The parts connected by welding will also be reinforced.

In the S-shaped bend pipe 1, the reinforcing layer 3 may be formed so as to cover only the curved intermediate portions 2a of the outer peripheral surface of the tubular body 2, or the intermediate portions 2a. The structure may be such that the portion 2a and the connected outer peripheral surface between the respective intermediate portions 2a are divided and coated.

[0028]

As described above, in the bend pipe and the method for producing the same according to the present invention, after the tubular body made of the olefin resin is curved and formed at a desired angle, the norbornene-based monomer is formed on at least the outer peripheral surface of the curved portion. After the secondary molding, which is a drawback of the olefin resin, which is the crystalline resin used as the material of the tubular body, the coating was formed by laminating a reinforcing layer made of a reaction injection molding material mainly composed of and a metathesis catalyst. The shape instability of the reaction injection molding material, which is firmly adhered to the olefin resin and is formed almost integrally with the olefin resin, stably maintains the curved shape obtained by the secondary molding. As a result, it is possible to obtain the effect of imparting long-term stability of the shape of the bend tube. That is, it is possible to obtain a bend tube having resistance to an acid or alkali of an olefin resin and having impact-resistant characteristics and long-term excellent shape stability characteristics.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a bend pipe according to the present invention.

FIG. 2 is an exploded perspective view of the external type.

FIG. 3A is a perspective view of a bend pipe according to another embodiment. FIG. 3B is a sectional view of the bend pipe.

FIG. 4 is a plan view of a bend pipe according to another embodiment.

FIG. 5 (a) is an explanatory view of a connecting procedure of pipes according to the other embodiment. (B) A plan view of the pipes.

FIG. 6 is an exploded perspective view of an outer mold of the other embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Bend pipe 2 ... Tube body 2a ... Midway part 3 ... Reinforcing layer 4 ... Outer mold

Claims (5)

[Claims] 1. A bend pipe comprising a tubular body made of an olefin resin and having a curved intermediate portion formed by secondary molding, wherein a norbornene-based resin is formed on at least the curved outer peripheral surface of the tubular body. A bend pipe characterized by being coated with a reinforcing layer made of a reaction injection molding material mainly composed of a monomer and a metathesis catalyst. 2. An S-shaped bend pipe obtained by butt-welding two bend pipes obtained by forming a pipe made of an olefin-based resin by secondary molding to form a curved middle portion. A bend pipe characterized in that a reinforcing layer made of a reaction injection molding material containing a norbornene-based monomer and a metathesis catalyst as a main material is formed to cover at least the curved outer peripheral surface in the middle part. 3. In the S-shaped bend pipe, a reaction injection molding mainly composed of a norbornene-based monomer and a metathesis catalyst is formed on an outer peripheral surface of at least two curved middle portions of the outer peripheral surface of the tubular body. The bend pipe according to claim 2, wherein a reinforcing layer made of a material is formed by coating. 4. A tubular body made of an olefin resin is formed by secondary molding so that the middle portion is curved, and then the tubular body is surrounded by an outer die, and the inner die and the outer die are surrounded. A reaction injection molding material containing a norbornene-based monomer and a metathesis catalyst as a main material is supplied to the gap between them to cause reaction curing, and a reinforcing layer of the reaction injection molding material is formed on the outer peripheral surface of the tubular body. A method of manufacturing a bend pipe, which is a feature. 5. An S-shaped bend pipe is formed by butt welding two bend pipes, each of which is formed by bending a tubular body made of an olefin resin by secondary molding. After that, the tube body is surrounded by an outer mold with the tube body as an inner mold,
A reaction injection molding material containing a norbornene-based monomer and a metathesis catalyst as a main material is supplied to the gap between the inner mold and the outer mold for reaction curing, and a reinforcement layer formed of the reaction injection molding material on the outer peripheral surface of the tubular body. A method for manufacturing a bend pipe, which comprises forming a coating.