JPH0374621B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of covering an elongated body having protrusions used as agricultural and horticultural supports.

(Prior art) Agricultural and horticultural supports used for growing plants that require measures to prevent stems from falling, such as vine plants, have a metal core that prevents the metal core from rusting. There are those that have a protective film formed on the material, and those that have an additional film welded and integrated on top of the protective film in order to avoid cracks and cracks in the protective film and prevent its deterioration. The latter is double-coated, and the protective film is formed by an inner coating layer made of vinyl chloride resin, while the film is made of acrylic, which is highly flexible, weather resistant, and crack resistant. It is said that it is preferable to form an outer coating layer made of resin.

In such double-coated agricultural and horticultural supports, protrusions may be formed at appropriate locations to improve cohesion and wrapping properties.

FIG. 2 shows an agricultural and horticultural support post in which protrusions a are formed at appropriate locations. When this agricultural and horticultural support is double-coated, the inner coating layer is made of vinyl chloride resin and the outer coating layer is made of acrylic resin as described above. As shown in FIGS. 3 and 4, the protrusions a are formed on an inner coating layer 1 made of vinyl chloride resin, which is usually protected by an outer coating layer 2 made of acrylic resin, which has excellent crack resistance. .

Such agricultural and horticultural supports are obtained by dividing a double-coated long body into predetermined lengths and subjecting the ends to a predetermined treatment. It was coated via a method.

That is, among the dies arranged in two stages, core material 3
The inner coating elongate body drawn through the former die which forms the inner coating layer 1 is pulled out through the latter die which extrudes the outer coating layer 2 in a cone shape, and the outer coating layer 2 is formed on the inner coating layer 1. This is a method of welding and integrating the two.

However, since the outer coating layer 2 is extruded in a cone shape from the latter die and is welded and integrated with the inner coating layer 1 of the inner coating elongated body that is drawn out through the latter die, the inner coating layer 1 is When the protrusion a is formed on the outer coating layer 2, the protrusion a
may be welded to the inner coating layer 1 while trapping the surrounding air. When such a situation occurs, a gap S is created between the inner coating layer 1 and the outer coating layer 2 around the protuberance a, as shown in FIG. In the case of a long body having such a gap S, the outer coating layer 2 is easily torn around the protrusion a, and since the shape of the protrusion a is not constant, the appearance thereof is also deteriorated.

(Problems to be Solved by the Invention) The problems to be solved by the present invention are that when covering an elongated body having projections, without creating a gap between the inner coating layer and the outer coating layer, The aim is to reliably weld and integrate the two.

(Means for solving the problem) A means for solving the above problem is to mutually connect the space between the front die and the rear die and the inner space of the outer coating layer extruded in a cone shape from the rear die. The goal is to create a closed space that communicates with the other, and to control the internal pressure of this closed space.

(Function) If the internal pressure of the sealed space is controlled to negative pressure in the above means, the outer coating layer will be sucked and welded and integrated with the inner coating layer, so that the two will be reliably welded and integrated even around the protrusion. be converted into

(Example) In Fig. 1, dies through which a metal core material 3 is penetrated and drawn are arranged in two stages, and a synthetic resin forming the inner coating layer 1, such as vinyl chloride resin, is extruded from the former die 11. , a synthetic resin forming the outer coating layer 2, such as an acrylic resin, is extruded from the rear die 12. Note that the arrow x in the figure indicates the direction in which the elongated body is pulled out.

In the above, while the recessed part 13 is formed at a suitable position around the resin extrusion port of the pre-stage die 11, the resin reservoir part 14 is formed in the resin passage inside the recessed part 13, and the inside of this resin reservoir part 14 is A resin extrusion tool 15 that can be moved forward and backward is provided.

In such a pre-stage die 11, the core material 3
Inner covering elongated body 100 formed by applying inner covering layer 1 to
is pulled out. Furthermore, when the resin extrusion tool 15 is moved in and out at a predetermined timing that matches the withdrawal speed of the inner coating elongated body 100, the synthetic resin in the resin reservoir 14 is forcibly extruded into the recess 13. Protrusions a are formed at appropriate locations on the inner coating layer 1.

The inner coating elongated body 10 described above is placed in the rear die 12.
A through hole 16 through which 0 passes is formed. Also,
The resin extrusion port 17 of the rear die 12 is connected to this through hole 16.
It is formed in an annular shape on the outside of the resin extrusion port 17.
The outer coating layer 2 extruded into a cone shape is formed into an inner coating elongated body 100 immediately in front of the rear die 12.
It is welded and integrated onto the inner coating layer 1 of. Therefore, between the resin extrusion port 17 and the starting point where the outer coating layer 2 is welded to the inner coating layer 1, the outer coating layer 2 is extruded into a cone shape and surrounds the inner coating elongated body 100. become a state.

Further, a cylindrical outer cover 18 is arranged between the front die 11 and the rear die 12, and the inner covering elongated body 100 is surrounded by the outer cover 18. . An air pipe 19 connected to a pneumatic control mechanism (not shown) is attached to the outer cover 18.

According to the above, the first die 11 and the second die 1
2 and the inner space of the outer coating layer 2 extruded in a cone shape from the rear die 12 are through holes 16.
It becomes a closed space that is interconnected with each other. The internal pressure of this sealed space can be freely controlled to either negative pressure or positive pressure with respect to the outside world by the pneumatic control mechanism.

Therefore, when the internal pressure of the sealed space is controlled to negative pressure, the cone-shaped outer coating layer 2 extruded from the rear die 12 is sucked inward, so that the inner pressure is not trapped around the protrusion a. It is welded and integrated with the coating layer 1 without any gaps. The magnitude of the negative pressure in this case varies depending on the type of resin of the outer coating layer and the thickness of the layer, but the magnitude of the negative pressure depends on the inner coating layer 1 and the outer coating layer 2 in a molten state, especially the outer coating extruded into a cone shape. layer 2
It is desirable that it be as large as possible without causing any deformation.

(Effects of the Invention) As is clear from the above, since the method of the present invention controls the internal pressure of a closed space, it is easy to operate and enables highly accurate control. Therefore, even if a protrusion is formed on the inner covering elongated body, the outer covering layer is sucked and welded and integrated with the inner covering layer, so that air is not trapped between the two layers. Therefore, a double-coated elongated body in which the inner coating layer and the outer coating layer are welded and integrated without any gaps can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of an apparatus for carrying out the method of the present invention, FIG. 2 is a partial perspective view of an agricultural and horticultural support;
Figure 3 is a cross-sectional front view of the above-mentioned support column, Figure 4 is a longitudinal side view of the same, and Figure 5 is an enlarged cross-section showing the main part of the elongated body in which the outer covering layer traps air and is welded to the inner covering layer. It is a diagram. 1... Inner coating layer, 2... Outer coating layer, 3... Core material, 11... Front die, 12... Back die,
100...Inner coated elongated body.

Claims (1)

[Claims] 1. The inner coat elongate body having the protrusion is pulled out through the front die which forms the inner coat layer on the core material, and is pulled out through the rear die which extrudes the outer coat layer in a cone shape, and the inner coat elongated body having the protrusion is pulled out through the rear die which extrudes the outer coat layer in a cone shape. In the above-mentioned method for coating a long body having protrusions for welding and integrating the outer coating layer, the space between the front die and the rear die and the inner space of the outer coating layer extruded in a cone shape from the rear die are communicated with each other. 1. A method for covering an elongated body having protrusions, the method comprising: forming a closed space in which the space is closed, and controlling the internal pressure of the closed space.