JP2000220787A - Joint made of hard vinyl chloride resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the construction mistake by worker, to facilitate the administration of production, and to enable the recycle of the forming raw material by forming a socket into a color transparent socket or a color translucent socket. SOLUTION: Since a socket part 11 of a joint 1 is formed into a color transparent socket or a color translucent socket, a hard vinyl chloride resin tube 2 can be inserted while visually confirming the inserting condition thereof at construction of piping. Construction mistake such as forgetting of coating with the adhesive agent and wrong setting of the insertion length can be prevented. Furthermore, unevenness of coloring at the time of manufacturing the joint 1 is restricted. In the case of coloring the socket part 11 with transparent yellow, even if color of the socket part 11 is changed a little by the heat at the time of forming the socket 11, it is inconspicuous, and transparency of the socket part 11 is not hindered, and characteristic as the joint 1 can be maintained. The runner to be generated at the time of injection molding is crushed and mixed with the virgin material for recycle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint used for piping a hard vinyl chloride resin pipe used in the field of piping such as for water supply and sewerage, hot water supply, a plant, and fire extinguishing equipment.

[0002]

2. Description of the Related Art Conventionally, hard vinyl chloride resin pipes (which are usually colored gray) are connected to each other by using a pipe joint made of hard vinyl chloride resin, which is colored in almost the same color as the resin pipe. TS bonding with the agent. By the way, at the time of plumbing, the worker forgets to apply the adhesive, or the insertion length of the hard vinyl chloride resin pipe into the pipe joint is short, and a sufficient bonding area cannot be secured. Then, there is a problem that water leaks from the connection part when water is passed or the connection part comes off due to internal water pressure.

As a solution to such a problem, for example, in Japanese Patent Publication No. Sho 59-40084, a pipe joint having pipe receiving portions at both ends is made colorless and transparent, and is different from a gray color of a hard vinyl chloride resin pipe. A method of connecting a plastic pipe has been disclosed in which the resin pipe and the pipe joint are bonded and connected using an adhesive colored in blue so that the blue color of the adhesive can be identified from the outside of the pipe receiving portion. I have.

[0004]

However, in the case of the above colorless and transparent pipe joint, particularly when the pipe joint is made of a vinyl chloride resin, the obtained pipe joint has a visual appearance depending on the production conditions and the production conditions of the raw resin. There was a problem that the color was different. Specifically, there is a tendency that yellowish yellow is more likely to occur when injection molding is performed using a large molding machine than when injection molding is performed using a small molding machine.

[0005] In general, vinyl chloride resin is colorless and transparent, but changes color to yellow due to heat history during production.
Further decomposes to red or brown when subjected to heat history. For this reason, in order to make it difficult to receive heat history, molding is usually performed by adding a compound called a stabilizer.
However, as described above, the color varies depending on the molding conditions, and moreover, reuse of runners and the like generated during manufacturing (in general, a method of partially mixing crushed materials such as runners with virgin raw materials). Will easily cause the transparent product to yellow.

As a method of reducing the degree of discoloration due to molding conditions, a method of increasing the amount of a stabilizer to be added is conceivable. However, since the heat distortion temperature of the molded article decreases,
It is not preferable for practical use. Further, in order to prevent yellowing, it is conceivable to increase the amount of the coloring agent added or to add a compound having a concealing property, but the transparency is sharply reduced, which is in line with the original purpose of preventing construction errors. Disappears.

[0007] Therefore, production management is very difficult, and it is extremely difficult to reuse runners and the like generated during injection molding, that is, to partially recycle virgin raw materials such as runners and the like. And had to be discarded. For this reason, not only is the raw material efficiency lowered, but also environmentally unfavorable.

An object of the present invention is to provide a pipe joint made of a hard vinyl chloride resin, which enables a worker to perform a pipe work satisfactorily without making a mistake in the work, has easy production control, and can be recycled as a molding material. is there.

[0009]

According to a first aspect of the present invention, there is provided a pipe joint made of a hard vinyl chloride resin, wherein a receiving portion is colored transparent or colored translucent.

In the present invention, that the receptacle is colored and transparent means that it is yellow, orange, red, or green. Specifically, pigments or dyes of yellow, orange, red, green, etc. may be added to and mixed with vinyl chloride resin which is a raw material for forming a pipe joint. The amount of each pigment or dye added depends on the type,
What is necessary is just to determine suitably so that transparency may not be impaired.

As described above, by making the receiving portion colored and transparent such as yellow, orange, red, and green, even if the vinyl chloride resin turns yellow due to the heat history at the time of molding, it is not apparent from the appearance. Or, it is difficult to understand in appearance. It is practical to make the entire pipe joint colored and transparent, not just the receptacle.

That is, when the pipe joint is yellow and transparent, the vinyl chloride resin is yellow and transparent even if it turns yellow. Further, when the pipe joint is orange and transparent, the color of the vinyl chloride resin is orange or slightly yellowish even when the vinyl chloride resin turns yellow. Further, when the pipe joint is red and transparent, even if the vinyl chloride resin turns yellow, it is red or orangeish red and transparent. Also, when the fitting is transparent in pink, the color is similar to that in the case of transparent red. And when a pipe joint is green transparent, even if resin turns yellow, it will become green or yellow-green transparent. As described above, in any case, there is not so much difference between the color of the original fitting and the color.

[0013] Most preferred are yellow transparent, then orange transparent and green transparent. Moreover, yellow transparent is more preferable than orange transparent or green transparent because light rays are easily transmitted, and the internal state of the receptacle, that is, the adhesive application state and the insertion amount of the tube are easily observed from the outside, and are most preferable.

[0014] When the pipe joint is colorless and transparent, when the vinyl chloride resin turns yellow, it becomes transparent and yellow, which is not preferable. The same applies to the case where the fitting is white and transparent. Further, when the pipe joint is transparent in blue, it is not preferable because the vinyl chloride resin becomes green and transparent when it turns yellow. Further, it is not preferable that the pipe joint is black transparent or gray transparent because it is difficult to externally observe the internal state of the receiving portion regardless of the yellowing of the vinyl chloride resin.

In the present invention, the receptacle may be colored and translucent. Here, translucent means a so-called ground glass state, which indicates that the outer surface state of the pipe joint is rough. By doing so, light is scattered, the amount of light reaching the inside of the receptacle portion is drastically reduced, and the occurrence of algae can be suppressed.

In order to make the receiving portion (or the entire pipe joint) translucent, for example, the surface state of the outer mold at the portion to be made translucent may be roughened.

(Function) In the invention according to claim 1 or 2, since the receiving portion of the pipe joint is colored transparent or colored translucent, the insertion state of the hard polyvinyl chloride resin pipe at the time of piping construction can be visually checked. It is possible to perform the work while checking it, and it is possible to prevent construction errors such as forgetting to apply the adhesive and setting the insertion length incorrectly. Further, variation in coloring at the time of manufacturing the pipe joint can be suppressed.

According to the second aspect of the present invention, since the receiving portion is made yellow and transparent, even if the color is changed to yellow to some extent due to the heat history during molding, it is not so noticeable, so that the transparency of the receiving portion is impaired. Therefore, the characteristics as a pipe joint can be maintained. Moreover, the runner generated during injection molding can be pulverized, mixed with the virgin material and reused, and is environmentally superior.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing an example of the pipe joint of the present invention together with a use state.

Reference numeral 1 denotes a socket joint made of hard vinyl chloride resin, and has sockets 11 at both ends. In this case, the entire socket joint 1 is yellow and transparent.
2 is a hard vinyl chloride resin tube colored red, for example.

The connection of the hard vinyl chloride resin tubes 2 and 2 using the socket joint 1 is performed as follows. The colorless and transparent adhesive 3 is applied to the outer surface of the end portion 21 of the hard vinyl chloride resin tube 2, and is inserted into the socket 11 of the socket joint 1 for connection. At this time, since the receiving portion 11 is transparent and yellow, the insertion state of the hard vinyl chloride resin tube 2 can be visually confirmed from the outside of the receiving portion 11.

[0022]

EXAMPLE A raw material having a different color of a pigment was prepared by a transparent composition using a vinyl chloride resin as a main raw material, and the nominal diameters of 13 mm and 75 mm in a shape conforming to JIS-K6743 (hard vinyl chloride resin pipe joint for water supply). The socket was molded. Then, while observing the color of the socket after molding, J
A blue-gray tube conforming to IS-K6742 was inserted and connected, and the ease of visual observation at the time of insertion and connection of the tube was evaluated. Table 1 shows the results.

As a comparative example, a conventional colorless and transparent pipe joint and a socket colored white, blue, and black with a predetermined pigment were molded in the same manner, and evaluated in the same manner as in the above-mentioned examples. Table 2 shows the results.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

According to the first or second aspect of the present invention, the receiving portion is made of colored transparent or colored translucent, so that the operator can visually check the insertion state of the hard vinyl chloride resin pipe at the time of piping construction. The pipe construction can be performed while checking, and it is possible to prevent construction errors such as forgetting to apply the adhesive and insufficient insertion of the pipe. Further, variation in coloring at the time of manufacturing the pipe joint can be suppressed.

According to the second aspect of the present invention, since the receiving portion is made yellow and transparent, even if the color is changed to yellow to some extent due to the heat history at the time of molding, it is not so noticeable. For this reason, the transparency of the receiving portion is not impaired, and the characteristics as a pipe joint are maintained. In addition, the runner generated during injection molding, which has been conventionally discarded, can be pulverized, mixed with the virgin material and reused, and is environmentally suitable.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of a pipe joint of the present invention together with a use state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Socket joint 11 Socket part 2 Hard vinyl chloride resin pipe 3 Adhesive

Claims (2)

[Claims] 1. A hard polyvinyl chloride resin pipe joint, wherein a receiving portion is colored transparent or colored translucent. 2. The rigid polyvinyl chloride resin pipe joint according to claim 1, wherein the receiving portion is yellow and transparent.