JPH1199560A - Plastic cylindrical molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic cylindrical molding generating no crack during use, reduced in wt., good in execution workability, inexpensive to produce, easily formed into a half-split shape or a flat plate-shape by post-processing and having mold patterns such as false wood patterns or the like formed on the surface thereof. SOLUTION: A plastic cylindrical molded object 10 has mold patterns 11 such as false wood patterns or the like formed on the surface thereof and the wall thickness thereof is 5-10 mm. This cylindrical molded object is obtained by extruding molten plastic to cover the surface of a cylindrical core member and continuously patterning the plastic coating layer during a period when the coated plastic is held to a softened state by a patterning roll having mold patterns such as false wood patterns or the like and subsequently pulling out the cylindrical core member to mold plastic into a cylindrical shape. This plastic cylindrical molded object is usually used in a cylindrical shape as it is but can be used in a state processed into a half-split shape or a flat-plate shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic cylindrical molded product having a surface pattern such as a pseudo-wood shape.

[0002]

2. Description of the Related Art For a building such as a park, a fence of a promenade, a retaining wall, and the like, a cylindrical composite molded body having a metal tube as a core material and the surface of which is covered with plastic having a pattern such as a pseudo-tree shape is used. It was started.

[0003] In this kind of pseudo-tree-like cylindrical composite molded article, the thermal expansion coefficient between the metal tube as the core material and the coating resin layer is greatly different, so that thermal expansion and thermal shrinkage are repeated during use, resulting in a coating. There is a disadvantage that cracks are easily generated in the resin layer.

In order to improve such disadvantages, Japanese Patent Application Laid-Open No. Hei 8-216276 discloses that a hollow portion of a plastic hollow molded article having a thickness of 10 to 50 mm and a length of 1 m or more is provided. There has been proposed a plastic hollow molded body in which a metal tube is filled as a core material while retaining a wall and a void.

[0005] The above-mentioned plastic hollow molded body uses upper and lower molds having a pseudo-wood-shaped pattern on the inner surface. A cooling core is inserted into the upper and lower molds while the upper and lower molds are open, and then the upper and lower molds are closed and Cooling is performed by passing cooling water through the mold and the cooling core, and the molten resin is poured into the upper and lower molds, the cooling core is pulled out of the cooled and solidified resin, and the upper and lower molds are opened to form a hollow molded body. It is manufactured by filling a metal tube.

[0006]

The plastic molded hollow article proposed above has a relatively thick plastic layer and uses a metal tube as a core material, so that it is heavy and difficult to carry during construction. In addition, there is a problem that the metal pipe as the core material is displaced from the plastic layer during the construction, and the construction workability is poor. Also, cutting is not easy.

[0007] The plastic hollow molded article is
Since it is obtained by a so-called casting method using upper and lower molds, to obtain long products having different lengths, upper and lower molds and cooling cores of corresponding dimensions are required, and equipment costs increase, and plastic There is a problem that the production cost increases due to the thickness of the layer and the use of a metal tube as the core material.

The present invention solves the above problems,
Its purpose is that it does not crack during use, it is lightweight and has good workability, it can be manufactured at low cost, and it is easy to cut and post-process it into a half-split shape or flat plate shape, An object of the present invention is to provide a plastic cylindrical molded body having a surface pattern such as a pseudo-wood shape.

[0009]

Means for Solving the Problems The plastic cylindrical molded article of the present invention is a cylindrical molded article made of plastic having a thickness of 5 to 10 mm with a pattern such as a pseudo-wood shape formed on the surface thereof. The cylindrical molded body is formed by melting and extruding plastic onto the surface of the cylindrical core body, and while the coating resin is in a softened state, performing continuous molding with a molding roll having a mold pattern such as a pseudo-wood shape. It is characterized by being formed into a tubular shape by pulling out a tubular core body, whereby the above object can be achieved.

[0010]

The plastic cylindrical molded article of the present invention has a thickness of 5 to 10 mm, is relatively thin, and does not use a core material such as a metal tube. Even if it is repeated, there is no crack in the plastic, and there is no trouble that the core material is shifted with light weight,
Construction workability is good. Further, since the core material is relatively thick and the core material is not used, the material cost is low, and it is easy to post-process the product into a half-split shape and a flat shape by cutting.

Furthermore, the plastic cylindrical molded article of the present invention can be obtained by a step of extruding and coating a plastic on a cylindrical core, a step of molding with a molding roll, and a step of drawing out the cylindrical core. Compared to those obtained by the casting method used, long products having different lengths can be obtained with the same equipment, and equipment costs are reduced. In addition, since the thickness is relatively small, that is, 5 to 10 mm, the molding distortion is small, and the cylindrical core can be easily pulled out from the coating resin layer.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. FIG. 1 is a partially cutaway perspective view showing an example of a plastic tubular molded article of the present invention, and FIG. 2 is an explanatory view showing an example of a method for producing a plastic tubular molded article of the present invention.

In FIG. 1, reference numeral 10 denotes a plastic cylindrical molded body of the present invention, and reference numeral 11 denotes a pseudo-wood-like pattern formed on the surface thereof. Here, as the plastic, a thermoplastic resin such as polyethylene, ethylene-vinyl acetate copolymer, and vinyl chloride resin is used. In addition, these thermoplastic resins include wood flour, short fibers, inorganic fillers,
A coloring agent, a foaming agent, a weather resistance improving agent, and other compounding agents may be added.

As the pattern pattern formed on the surface, various pattern patterns having various three-dimensional appearances such as bamboo-like, stone-like, mosaic-like, screw-like, etc. are adopted. Further, the cross-section of the cylindrical molded body 10 may be not only circular but also elliptical or square.

The thickness of the plastic cylindrical molded body 10 is 5 to 10 mm. When the thickness is less than 5 mm, the mechanical strength is reduced. On the contrary, when the thickness is more than 10 mm, not only the material cost is increased but also the molding distortion is increased, and the coating resin layer is formed at the time of molding the plastic cylindrical molded body 10. It becomes difficult to pull out the cylindrical core from the slab, and it becomes difficult to post-process the product into a half-split or flat product by cutting. Here, the thickness refers to the entire thickness including the pattern.

As shown in FIG. 2, the plastic cylindrical molded article 10 of the present invention is a cross-head mold 2.
1, a plastic extruder is melt-extruded from the screw extruder 20 to the crosshead mold 21 while introducing a cylindrical core 30 such as a metal tube into the crosshead mold 21 using the screw extruder 20 provided with Plastic is melt-coated on the surface of the cylindrical core body 30 in the crosshead mold 21 to form a coating resin layer 10a.

Next, the temperature of the coating resin layer 10a is controlled to be cooled to the softening temperature of the resin by the cooling device 40, and the coating resin layer 10a is cooled.
Is in a softened state, is passed between a pair of molding rolls 50 having a pattern such as a pseudo-wood shape, where the coating resin layer 1 is formed.
A pattern 11 such as a pseudo-tree shape is continuously formed on the surface of Oa. Each of the pair of molding rolls 50 has a drum shape, and the coating resin layer 10a is supported by the cylindrical core 30, so that the molding is easy.

Thereafter, the cylindrical core 3 is removed from the coating resin layer 10a.
By drawing 0, it is formed into a cylindrical shape. In order to pull out the cylindrical core 30 from the coating resin layer 10a, the cylindrical core 3
The surface of No. 0 is treated with a silicone-based release agent or a fluorine-based release agent, lubricating oil is further applied, and the surface of the coating resin layer 10a is fixed with a fixing device equipped with a rubber with good non-slip properties. The tubular core 30 is easily pulled out by pulling only the tubular core 30 using an appropriate tensioning tool.

In addition, the cylindrical core 30 may be constituted by a split mold that can be reduced, and the split core may be reduced to pull out the cylindrical core 30. In this way, a plastic cylindrical molded body 10 having the surface on which the pattern 11 such as a pseudo-tree shape is formed is obtained.

The plastic cylindrical molded body 10 of the present invention
Is cut into a suitable length, and a large number of them are arranged or combined to construct, for example, parks, fences such as promenades, etc.
Used for retaining walls. In this case, a cap is usually put on the upper end or both ends of the plastic cylindrical molded body 10.

Further, the plastic cylindrical molded body 10 of the present invention has a relatively small thickness and does not have a core material such as a metal tube, so that it is easy to process. Afterwards, it can be used for wall materials and roof materials.

[0022]

The plastic molded article of the present invention is
Because it is configured as described above, it does not crack during use, and it is lightweight, has good workability, and can be manufactured at low cost. Since the imitation wood-like pattern is formed, it can be used in a wide range of applications such as structures such as parks, fences such as promenades, retaining walls, wall materials and roof materials.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an example of a plastic cylindrical molded body of the present invention.

FIG. 2 is an explanatory view showing an example of a method for producing a plastic cylindrical molded body of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Plastic cylindrical molded body 10a Coating resin layer 11 Pseudo wood-like pattern 20 Screw extruder 21 Cross head type mold 30 Cylindrical core body 40 Cooling device 50 Molding roll

Claims (1)

[Claims] 1. A cylindrical molded body made of plastic having a pattern such as a pseudo-wood shape formed on the surface thereof and having a thickness of 5 to 10 mm, wherein the cylindrical molded body has a plastic core on the surface of a cylindrical core. Was melt-extruded and coated, while the coating resin was in a softened state, continuously molded by a molding roll having a mold pattern such as a pseudo-wood shape, and then formed into a tubular shape by pulling out the tubular core body. A cylindrical molded article made of plastic, characterized in that: