JP3503041B2 - Synthetic resin wire and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a synthetic resin wire used for resin welding or the like.

[0002]

2. Description of the Related Art Almost all synthetic resin wires such as polyethylene used for resin welding are round wires having a circular cross section. As shown in FIG. 3, the synthetic resin wire 100 is formed by extrusion-molding a thermoplastic synthetic resin softened and melted from a die 101 a of an extrusion molding machine 101 into a round wire shape, and then heating the hot water tank 102.
And is slowly cooled by passing through a cold water tank 103.

[0003]

However, when the round wire extruded product is gradually cooled as in the above-described manufacturing method, the cooling time becomes long and the extrusion speed becomes slow, so that the synthetic resin wire 100 can be manufactured efficiently. There was a problem that it was difficult to do.

As a solution to such a problem, it is considered that a round wire-shaped extruded product is rapidly cooled to shorten the cooling time. However, when the extruded product is rapidly cooled, distortion occurs, which results in a distorted synthetic resin wire 100 having a substantially elliptical cross section and a non-uniform wire diameter.
It is difficult to smoothly supply 00 to the resin wire supply hole of the welding gun, and there is a fatal drawback that the commercial value of the synthetic resin wire for resin welding is significantly impaired. For this reason, the extrusion speed is set as slow as about 3 to 4 m / min, and the hot water tank 102 and the cold water tank 103 are set so as not to cause distortion.
The reality is that it must be slowly cooled through.

The present invention has been made in view of the above circumstances, and an object thereof is to extremely efficiently manufacture a round wire of a synthetic resin having a uniform wire diameter and no distortion.

[0006]

In order to achieve the above object, a method for producing a synthetic resin wire according to the present invention comprises a step of extruding a softened and melted thermoplastic synthetic resin into a linear shape from a die of a first extruder. Then, this linear molded body is rapidly cooled and then passed through a T die of a second extruder to coat the linear molded body with the same softening and melting synthetic resin into a cylindrical shape, and the coated linear molded body is again It is characterized by rapid cooling.

[0007]

When the linear molded body extruded from the die of the first extruder is rapidly cooled as in the manufacturing method of the present invention, the linear molded body is distorted and has a diameter of a substantially elliptical cross section. It becomes a non-uniform linear molded body. However, when this linear molded body is further passed through the T die of the second extrusion molding machine to be cylindrically coated with the same resin, even if the coated molded body is rapidly cooled again, the coating layer is not distorted. It is possible to obtain the synthetic resin wire of the present invention in which the outer contour shape of the cross section of the coating layer is substantially a circle and the wire diameter is uniform and free from distortion. The reason why the coating layer is not distorted is not clear, but it is probably that the coating layer is cooled from the inside and outside by using the cooled linear molded body as the core wire, and the outer contour shape of the perfect circle coming out from the T-die. Is supposed to hold. As described above, the manufacturing method of the present invention can obtain a round synthetic resin wire having a uniform wire diameter and no distortion even if it is rapidly cooled. Therefore, the extrusion speed can be greatly increased and the manufacturing can be performed extremely efficiently.

As the thermoplastic synthetic resin of the material, an olefin resin such as polyethylene or polypropylene is suitable. When such an olefin resin is used, the linear molded product and the coated linear molded product are 20 to 80. Rapid cooling to the temperature range of ℃ is desirable.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the synthetic resin wire of the present invention, and FIG. 2 is an explanatory view showing an embodiment of the manufacturing method of the present invention.

The synthetic resin wire 10 illustrated in FIG. 1 comprises a core wire 11 made of an olefinic resin such as polyethylene or polypropylene, and a coating layer 12 of the same resin provided around the core wire 11. The core wire 11 is rapidly cooled after extrusion molding. Distortion is generated by the treatment, resulting in a non-uniform diameter core wire having a substantially elliptical cross section. On the other hand, the coating layer 12 has no distortion, the outer contour shape of its cross section is substantially a perfect circle, and its diameter is constant. Therefore, the synthetic resin wire 10 is a round wire having a uniform diameter as a whole and having no distortion, and can be smoothly supplied to the resin wire supply hole of the welding gun.

The diameter of the core wire 11 (average diameter) and the outer diameter of the coating layer 12 (wire diameter of the entire synthetic resin wire) are not particularly limited, but considering the use of resin welding, the average diameter of the core wire 11 is ~ 3.5 mm, the outer diameter of the coating layer is 2.5 ~ 4.5
It is preferably about mm.

Needless to say, a thermoplastic synthetic resin other than olefin may be used as the material resin.

The synthetic resin wire 10 as described above can be efficiently manufactured by the manufacturing method illustrated in FIG.

First, from the die 1a of the first extruder 1, the above-mentioned softened and melted polyolefin-based resin
It is extruded into a round wire having a diameter of 3.5 mm, and the linear molded body 11 serving as the core wire is passed through the first cold water tank 3 to be rapidly cooled. In that case, the resin temperature at the outlet of the die 1a is set to 140 to 22.
It is desirable to adjust the length of the cold water tank 3 and the temperature of the cold water so that the linear molded body 11 is rapidly cooled to a temperature range of 20 to 80 ° C. while passing through the cold water tank 3 by adjusting the temperature in the range of 0 ° C. .
When rapidly cooled in this manner, the linear molded body 11 serving as the core wire is distorted, and the linear molded body 11 having a substantially elliptical cross section and having a non-uniform diameter is formed as shown in FIG.

Next, the linear molded body 11 is passed through the T die 2a of the second extruder 2 and softened and melted 140-2.
The outer diameter of the linear molded body 11 is 2.5-
A coating layer 12 is formed by coating in a cylindrical shape of about 4.5 mm, and the coated linear molded body is passed through the second cold water tank 4 until the coating layer 12 reaches the temperature range of 20 to 80 ° C again. Quench quickly. Even if it is rapidly cooled in this way, as described above, the coating layer 12
Since there is no distortion, the synthetic resin wire 10 in which the outer contour shape of the cross section of the coating layer 12 is substantially a circle and the wire diameter is uniform and has no distortion can be obtained.

In this manufacturing method, since the round synthetic resin wire 10 having no distortion can be obtained despite the rapid cooling step, the extrusion speed can be greatly increased and the synthetic resin wire 10 can be manufactured extremely efficiently. For example, the die 1 of the first extruder
a and the distance P1 between the T die 2a of the second extruder and 150
cm, the first cold water tank 3 having a length L of 60 cm is installed at an intermediate position, and the length L is also 60 cm.
The second cold water tank 4 is installed at a distance P2 of 75 cm from the T die 2a of the second extruder, and cold water of 10 ° C. is supplied into the first and second cold water tanks 3 and 4. When cooling the linear molded body and the coated linear molded body, the extrusion speed is 60 m /
Even if the temperature is raised to about min, it can be rapidly cooled to a temperature range of 20 to 80 ° C. while passing through the cold water tanks 3 and 4, so that the wire diameter is uniform and strain-free at an extrusion speed 10 times or more that of the conventional manufacturing method It becomes possible to manufacture the synthetic resin wire 10.

In this embodiment, the synthetic resin is extruded in the shape of a round wire from the die 1a of the first extrusion molding machine 1.
It may be extruded into a linear shape having a rectangular or triangular cross-sectional shape. In that case, a synthetic resin wire in which the cross section of the core wire is distorted into a substantially square shape or a substantially triangular shape can be obtained.

[0020]

As is clear from the above description, the synthetic resin wire of the present invention has the outer contour of the cross section of the coating layer which is a perfect circle without distortion and has a uniform wire diameter. The synthetic resin can be smoothly supplied to the supply holes, and the production method of the present invention has a remarkable effect that the synthetic resin can be produced extremely efficiently at an extrusion speed 10 times or more that of the conventional method.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a synthetic resin wire of the present invention.

FIG. 2 is an explanatory view showing an embodiment of a manufacturing method of the present invention.

FIG. 3 is an explanatory view showing a conventional method for manufacturing a synthetic resin wire.

FIG. 4 is a cross-sectional view of a synthetic resin wire obtained when a linear molded body is rapidly cooled by a conventional manufacturing method.

[Explanation of symbols]

1 The first extruder 1a The die of the first extruder 2 Second extruder 2a T die of the second extruder 3 First cold water tank 4 Second cold water tank 10 synthetic resin wire 11 core wire (linear molded body) 12 coating layer

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Hosokawa 2-3-13 Azuchi-cho, Chuo-ku, Osaka Takiron Co., Ltd. (56) References JP-A-8-1746 (JP, A) 44-28509 (JP, Y1) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B29C 47/00-47/96

Claims (2)

(57) [Claims] 1. A thermoplastic synthetic resin softened and melted is extruded into a linear form from a die of a first extruder, and the linear compact is rapidly cooled and then passed through a T die of a second extruder. ,
A method for producing a synthetic resin wire, characterized in that a linear molded body is cylindrically coated with the same softened and melted synthetic resin, and the coated linear molded body is rapidly cooled again. 2. The thermoplastic synthetic resin is an olefin resin such as polyethylene or polypropylene, and the linear molded body and the coated linear molded body are rapidly cooled to a temperature range of 20 to 80 ° C. 1. The manufacturing method according to 1.