JPH10178942A - Irrigation pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an irrigation pipe which has high bending rigidity, lightness in weight and durability and has properties adequate for secondary fabrication by forming an intermediate layer of a fiber reinforced thermosetting resin and integrally molding an inside layer and outside layer consisting of thermoplastic resins in its inner peripheral part and outer peripheral part. SOLUTION: For example, a pipe 1 consists of the intermediate layer 2 consisting a main body and the inside layer 3 and outside layer 4 integrally molded on its inner and outer peripheral parts. The intermediate layer 2 is obtd. by mixing the thermosetting matrix resin, such as epoxy or unsatd. polyester resin, with reinforcing fibers, such as glass fibers, which are the main strength member of the pipe 1 and curing the mixture. The inside layer 3 and the outside layer 4 are composed of the thermoplastic resins (e.g. ABS, AS, AAS, PS, PC, PPE, PVC, etc., and having the chemical affinity for the thermosetting resin of the intermediate layer 2), by which the desired irrigation pipe is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an irrigation pipe using a fiber-reinforced thermosetting resin.

[0002]

2. Description of the Related Art In general, PVC (polyvinyl chloride) is generally used as a material for pipes used as irrigation pipes in a greenhouse or the like. Attach nozzle, PV
Pipe connection is made in the required arrangement on the top of the plant using a pipe connection joint such as elbow or cheese made of C, and the upstream pipe is connected to a water source via a pump or the like, and the pump is periodically driven. The plants are irrigated by flowing water inside the pipes.

[0003]

The PVC pipe is a thermoplastic resin, and is easily deformed due to a rise in the temperature in the house, and easily cracked in the winter season. Otherwise, the growth of crops in the house will fail. Even when there is no temperature rise, if the flexural rigidity is low and the distance between the support points of the suspension element is wide, the material tends to bend under its own weight, and permanent deformation such as drooping due to creep phenomenon due to long-term static load. Easy to occur.

[0004] Therefore, although the manufacturing unit price is low, there is a drawback that maintenance costs for periodic replacement increase.

When a fiber reinforced thermosetting resin (hereinafter abbreviated as FRP) is used as a pipe material instead of the PVC pipe, FPP is originally a material having high bending rigidity and hardly causing creep and the like. In addition, even if they have the same outer diameter, they can be made lightweight and are suitable as a durable pipe material.

However, on the other hand, in order to use an FRP pipe as an irrigation pipe, it is necessary to perform drilling, cutting, tapping for connection with a watering nozzle, and a pipe connection part, and die processing. However, it is poor in any machinability, poor in compatibility with adhesive, poor in sealability, and easily damaged by workers due to reinforcing fibers such as glass fiber exposed at the cut end, and furthermore the manufacturing unit price is expensive. For such reasons, it has not been put to practical use.

[0007] The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a material for an irrigation pipe as F material.
While enjoying the above-mentioned advantages of using RP,
An object of the present invention is to provide an irrigation tube capable of improving the drawbacks such as machinability, adhesiveness, and sealability.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, the intermediate layer is made of a fiber-reinforced thermosetting resin, and the inner and outer peripheral portions thereof are provided. And a pipe formed by integrally molding an inner layer and an outer layer made of a thermoplastic resin.

Therefore, according to the present invention, the intermediate layer is made of F
By using RP, the strength is improved, the weight can be reduced with the same outer diameter, and the physical properties suitable for the secondary processing as the irrigation pipe such as machining, bonding, and sealing with thermoplastic resin on the inner and outer circumferences Can be obtained.

[0010] According to a second aspect of the present invention, in the first aspect, the thermoplastic resin constituting the inner layer and the outer layer is ABS, AS, AAS, AES,
It is characterized by being one kind selected from PS, PC, PPE and PVC, or one or more polymer alloys selected from these.

The above-mentioned thermoplastic resin is first extruded into a pipe shape, and this is used as a core material to form an intermediate layer made of FRP by a pultrusion molding, a filament winding molding method, and the like. Extruded into

It is desirable that the FRP intermediate layer and the resin be integrally bonded, and by integrally bonding, the bending rigidity, machinability, adhesiveness, and sealability as an irrigation tube are improved. be able to.

Further, when the resin is a polymer alloy, it is necessary that the resin is compatible and compatible with each other, and that the required properties in an alloyed state are satisfied.

[0014]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a sectional structure of a pipe 1 serving as an irrigation pipe according to the present invention. This pipe 1 has an intermediate layer 2 constituting a main body.
And an inner layer 3 and an outer layer 4 integrally formed on the inner and outer circumferences thereof.
It consists of

The intermediate layer 2 serves as a main strength member of the pipe 1, and is obtained by mixing a reinforcing fiber such as a glass fiber with a thermosetting matrix resin such as an epoxy or unsaturated polyester resin and curing the mixture. . Examples of the forming method include a pultrusion method, a filament winding method, and a tape winding method.

As the reinforcing fiber, other materials such as carbon fiber and boron can be used, but glass fiber is preferable because it is expensive.

The inner layer 3 and the outer layer 4 are made of a thermoplastic resin, and function as a protective layer for an operator by preventing adhesion of the adhesive to an adhesive, sealing properties, and fluffing of the fibers of the intermediate layer 2. .

As such a thermoplastic resin, one having a chemical affinity with the thermosetting resin of the intermediate layer is used. For example, ABS (acrylonitrile-butadiene-
(Styrene resin), AS (acrylonitrile-styrene resin), AAS (acrylonitrile-acryl-styrene resin), PS (polystyrene resin), PC (polycarbonate resin), PPE (modified polyphenylene ether resin; graft copolymer of polyphenylene and polystyrene) ), PVC (polyvinyl chloride resin) and the like.

Since the thermoplastic resin is integrally adhered to the intermediate layer, a good thread can be obtained in the tapping process when attaching the watering nozzle,
Furthermore, since it has an adhesive property with an existing PVC adhesive or sealing material, it is a piping material that can be easily connected by using existing PVC pipe connecting parts.

Further, in forming the above-mentioned various resins into a polymer alloy, it is desirable that the resin is rich in mutual affinity and compatibility, and has properties satisfying required physical properties in an alloyed state. Specific properties include, for example, PC / ABS, nylon / ABS, PS / PPE, etc. as alloys for further improving heat resistance, durability, and moldability, and also improve chemical resistance to water spray. An alloy resin of the above resin and a polyolefin resin such as polyethylene and polypropylene may be used.

As a method of manufacturing the above-mentioned pipe 1, there are:
For example, the following method can be exemplified.

First, the inner layer 3 of the thermoplastic resin is extruded into a pipe shape by a first extruder to be continuously molded and solidified, and then the thermosetting resin-impregnated reinforcing fibers constituting the intermediate layer 2 are continuously coated. It is shaped annularly and the thermoplastic outer layer 4 is further coated by a second extruder.

Next, the pipe-like material continuously formed in this way is immediately put into cooling water to cool and solidify the outer layer 4, and then passed through a hot water tank arranged on the same line. By heating and curing the thermosetting resin of the intermediate layer 2, the composite pipe 1 of the present invention is obtained.

Further, when the above pipe 1 is used as an irrigation pipe, the outside diameter and the inside diameter (mm) of a conventional PVC pipe used as an irrigation pipe are 3 mm.
Since they are 2 × 25, 38 × 30, and 48 × 40, they are manufactured in consideration of these dimensions. However, since the practical water pressure resistance is usually 7 kg / cm ² conventionally, it is 10 kg / cm 2.
^The thickness of the intermediate layer 2 as a strength member is set so as to have a pressure resistance of ² .

When the watering nozzle is mounted, a hole is formed by machining, and then a tap is made. In order to connect the screw to the male screw portion of the watering nozzle, the entire thickness corresponding to the number of the thread is formed. Thickness is also considered.

FIG. 2 shows an example of a pipe connection using the pipe 1 described above. A main pipe A vertically plumbed is provided at a corner of the greenhouse 5, and pipes B and C connected to the upper end of the main pipe A via an elbow L and a stepped socket RS1 are horizontally piped. . The pipes B and C are connected by a cheese T, and the pipe 1 according to the present invention connected to the cheese T via a stepped socket RS2 is horizontally piped along the longitudinal direction of the house 5. At the end of the pipe C, a pipe 1 according to the present invention connected via an elbow L2 and a stepped socket RS2 is horizontally piped at a predetermined interval in parallel with the pipe 1. In addition, the pipes 1,
1 are connected by a socket S. Also,
The ends of the pipes 1 and 1 are sealed with a hermetic plug (not shown).

These sockets S, RS1, RS2, elbows L1, L2, cheese T, hermetic plug, and sleeve S are made of existing P
When the pipe 1 is made of VC and is directly connected via an adhesive or a sealing material, the pipe 1 needs to have an outer diameter corresponding to the inner diameter thereof, and the They are connected by fitting.

In the case of joining by screw connection, it is necessary to dice the outer periphery of the joining end of each pipe 1. In this case, it is necessary to set the nominal diameter of the externally threaded portion to be processed to be equal to or less than the thickness of the outer layer 4 so that the processed portion does not reach the intermediate layer 2. The thickness of the outer layer 4 is set.

Further, a watering nozzle 6 is attached to the lower side of the pipes 1, 1 at a predetermined interval. As shown in FIG. 3, the water spray nozzle 6 has a nozzle portion 6 for spraying water.
A male screw part 6b for mounting is formed on the upper part of
The lower side of the pipe 1 is drilled and further tapped to form a female screw portion 1a. In the formation, it is necessary to secure the screw thread so that the male screw portion 6b is screwed and fixed stably, and conversely, the entire thickness is set according to the number of the screw thread.

The irrigation tube assembled as described above is supported at a predetermined interval via a suspender (or bracket) or the like. Since the amount of deflection per length is extremely small, the distance between support points can be sufficiently long as compared with a conventional PVC irrigation tube. Also, since no long-term creep occurs, there is no need for replacement or the like, and the piping is once maintenance-free.

[0031]

Next, specific examples will be described. The present invention is not limited only to the following examples.

Example: A prototype pipe having an average outer diameter of 38 mm, an average inner diameter of 31 mm, and an average thickness of 3.5 mm, an intermediate layer FRP: 1.7 mm in thickness, an inner layer ABS: 1.2 mm in thickness, and an outer layer ABS: Water pressure test for a pipe having a thickness of 0.6 mm and a conventional PVC pipe,
A tapping test, a bending property, and a comparative test of linear expansion coefficient measurement were performed.

The dimensions of the conventional PVC pipe to be compared were an average outer diameter of 38.2 mm, an average inner diameter of 31.2 mm,
It has an average thickness of 3.5 mm and has the same dimensions as the product of the present invention.

Hydraulic pressure test: Water was injected into the product of the present invention and the comparative product, both ends of which were formed into an appropriate pipe shape using the various pipe connection parts described above, and pressurized using a manual hydraulic pump. Left at 10 kg / cm ² for 1 hour,
No abnormality such as leakage was observed in both cases.

Tapping test: watering nozzle (screw diameter 1)
1 mm) was carried out. Working pressure of nozzle to be installed is 0.5 to 2.0k
gf / cm ² , the amount of sprinkling water is 1.8 to 7.3 l / min.
, The flow rate range is color-coded and the watering radius is 2 to 5.5 m. Prepared hole diameter 10.2mm, 9.8m
m, 9.4 mm, and a tap having a diameter of 11 mm was made on the three types to cut a screw.

In the case of the product of the present invention, as in the case of the PVC pipe of the comparative product, good thread cutting could be performed in any of the pilot holes. Since the tap passes through the FRP portion of the intermediate layer, the occurrence of burrs at this portion was predicted.
Since they were integrally bonded with each other, it was confirmed that no burrs were formed and that the thread was formed well, and that there was no problem with the nozzle mounting properties.

Bending properties: Various bending properties were measured for each size shown in Table 1, including the conventional PVC pipe, as the outer diameter of the prototype. Table 1 shows the obtained results.

[0038]

[Table 1] The flexural modulus * 1) is determined by a flexural test (crosshead speed 20 mm / min, distance between supports; 40 times the outer diameter) according to JIS K6911.
m ² ) was measured.

As shown in FIG. 4, the deflection (D) of the sample under its own weight was measured (Span length L = 3.5 m).

The amount of flexure when filled with water * 3) was measured in the same manner as in the above-mentioned * 2) after water was poured into the test pipe until it was fully filled.

From the results in Table 1, it can be seen that the flexural modulus is
It is about 5 times that of VC pipes, and the amount of deflection is about 1/4 to 1/6 when actually used (full water) compared to conventional products.
Therefore, the number of suspenders (brackets) when constructed as irrigation pipes can be reduced, and labor for irrigation equipment construction can be saved.

Further, it can be seen from the fact that there is almost no product warpage and the linearity is excellent, and that the workability is excellent.

Measurement of linear expansion coefficient: A strain gauge was attached in the length direction of the surface of the test piece, and the strain amount from room temperature (23 ° C.) to 60 ° C. was measured. As a result, the product of the present invention was 1.3
× respect ^10-5 of a cm / cm / ℃ ^-1, in the comparative product showed a ^{4.3 × 10 -5 cm / cm /} ℃ -1 to about 3 times the thermal expansion properties. In other words, it is shown that, when the irrigation pipe is fixed with a suspender, the conventional PVC pipe is easily deformed about three times due to a rise in temperature.

[0044]

As is apparent from the above description, the irrigation pipe according to the present invention has the disadvantages of machinability, adhesiveness, and the like, while enjoying the advantages of using FRP for the pipe. Sealing properties can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a pipe constituting an irrigation pipe according to the present invention.

FIG. 2 is a perspective view showing a connection pipe model of the pipe.

FIG. 3 is a partial cross-sectional view showing an attachment shape of a watering nozzle to the pipe.

FIG. 4 is a schematic diagram illustrating the amount of deflection of a wire supported between two points.

[Explanation of symbols]

 1 pipe 2 middle layer 3 inner layer 4 outer layer

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shigehiro Matsuno 2-1-1 Yabuta Nishi Ube Nitto Kasei Co., Ltd.

Claims (2)

[Claims] 1. An irrigation pipe characterized in that the intermediate layer is made of a fiber-reinforced thermosetting resin, and is formed of a pipe in which an inner layer and an outer layer made of a thermoplastic resin are integrally formed on an inner peripheral portion and an outer peripheral portion thereof. 2. The thermoplastic resin constituting the inner layer and the outer layer is made of ABS, AS, AAS, AES, PS, PC, P
The irrigation tube according to claim 1, wherein the irrigation tube is one selected from PE or PVC, or one or more polymer alloys selected from these.