JPH0939113A - Manufacture of tube with texture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a tube with a craped texture which can produce the tube which is free from wrinkles, a flash, and the nonuniformity and dislocation of a craped pattern on the outer surface and has a beautiful appearance continuously and stably. SOLUTION: After a foamed resin tube having a polygonal (e.g. square) cross section is extrusion-molded, a coating resin is extruded onto the outer surface of the tube to obtain the foamed resin tube T2 in which the outer surface is coated with a film-shaped coating resin layer C. The tube T2 is passed through a heater 6 to heat the surface of the coating resin layer C and a craping device 7 and given a craped pattern by being pressed by a pair of cylindrical rolls (craped pattern giving members) 71 which have the unevenness of a craped pattern on every polygonal surface and are arranged on the right and left and a pair of cylindrical rolls 72 to obtain a tube T3 with a craped texture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a wrinkled tube used for the purpose of keeping the tube warm.

[0002]

2. Description of the Related Art For example, in order to keep a pipe for air conditioning warm,
A tube molded product made of foamed resin such as highly cross-linked foamed polyethylene is provided, but in order to prevent wrinkles from occurring during bending work or to absorb wrinkles and make them inconspicuous, In order to prevent the tube from being damaged by pulling or rubbing, a foamed resin tube having a textured pattern on its outer surface (hereinafter referred to as a textured tube) is used.

As the embossed tube, a foamed sheet has been laminated with a film, subjected to embossing, wound in a tubular shape and tubed, and an extruded foamed resin tube having a textured film on its surface. Some were sheet coated. However, such a wrinkled tube is difficult to manufacture in a continuous manufacturing process, and its productivity is low, resulting in high cost.

As a method for continuously producing a textured tube with improved productivity and cost, a foamed resin tube is extruded and a resin is extruded on the outer surface of the resin into a film or foam. It is covered continuously by pressing it with two or more hourglass-shaped rolls having a cross-sectional roll surface with a circle having a diameter slightly smaller than the outer diameter of the coating layer and divided into two or more arcs. A method of applying a texture treatment (Japanese Patent Laid-Open No. 3-207639), and a reticulated body that continuously circulates endlessly at the same speed as a film-covered foamed resin tube is passed through a round tube to form a cylindrical shape. A method for wrapping a film-covered foamed resin tube with a ring-shaped portion and applying an internal pressure to the tube to heat the outer peripheral surface to bring it into contact with a net-like body to form an embossed pattern (JP-A-7-88956). It has been proposed.

[0005]

However, Japanese Patent Application Laid-Open No.
In the method described in JP-A-207639, since a plurality of hourglass-shaped rolls are used, a slight gap is formed between the rolls, resulting in poor texture patterning, burrs on the surface of the tube, and between the rolls. It may be difficult to perform stable production because of the deviation and unevenness of the grain pattern.

In the method described in Japanese Patent Application Laid-Open No. 7-88956, the joints at both ends of the net-like body are not completely closed to form a gap, or both ends are lifted up, resulting in an unclear band-like or streak-like grain pattern. There may be parts. Further, if the outer diameter of the film-covered foamed resin tube is too small, the grain pattern becomes unclear, and if it is too large, the grain pattern becomes clear but burrs occur at the joints, or if it is severe, the film-coated foamed resin tube becomes It may be cut off.

Therefore, as a result of studying the above-mentioned prior art, since the external cross-sectional shape of the embossed tube is circular, there is a gap between the rolls and the joints at both ends of the mesh body are not completely closed. It is easy to create gaps on the edges or lift up both ends, which causes the grain pattern to become unclear, unevenness or burrs in the pattern at the joints of the roll or mesh, and excessive force to apply the film. It was concluded that accidents such as cutting of the coated foamed resin tube are likely to occur.

The present invention has been made in view of the above problems of the prior art, and has a uniform and beautiful appearance on the outer surface of the foamed resin tube without wrinkles, burrs, shifts of grain pattern or unevenness. It is an object of the present invention to provide a method for producing a textured tube, which enables continuous and stable production of the textured tube.

[0009]

In order to achieve the above object, a method for producing a textured tube according to the present invention is a foamed resin having a polygonal outer cross-sectional shape in which a film-shaped coating resin layer is coated on the outer surface. The gist of the present invention is to apply a grain pattern by pressing a grain pattern imparting member to each surface of the tube.

In the present invention, a foamed polyolefin is preferably used as the material of the foamed resin tube, but other materials such as urethane foam, polyvinyl chloride foam,
A rubber sponge or the like may be used.

The coating resin for forming the coating resin layer includes low-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate, propylene or their derivatives, and heat. A plastic elastomer or a mixture thereof is used. Further, the thickness of the coating resin layer is preferably 30 μm to 1 mm, for example, 70 to 100 μm in the case of a pipe heat insulating tube for air conditioning, and 200 to 400 μm in the case of a pipe heat insulating tube of a solar heat utilization device.

Although the polygonal outer cross-sectional shape of the foamed resin tube is not particularly limited, it is covered (heat retention).
There is an extremely thin part in the thickness and the heat retention effect decreases,
It is desirable to have a shape that does not hinder installation.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An example of a wrinkled tube having a square outer cross-sectional shape will be described below with reference to the drawings. FIG. 1 is an explanatory view of a manufacturing process of a foamed resin tube having a polygonal (square in this example) outer cross-sectional shape in which a film-shaped coating resin layer is coated on the outer surface in the present invention,
2 (A) is a vertical cross-sectional view showing a portion of a foamed resin tube molding die, (B) is a cross-sectional view taken along line XX in (A), and FIG. 3 is a resin coated on the outer surface of the foamed resin tube. FIG. 4 is a longitudinal sectional view of a crosshead die for coating the layers, FIG. 4 is a transverse sectional view of the foamed resin tube before being coated with the coating resin layer, and FIG. 5 is foaming in which a film-shaped coating resin layer is coated on the outer surface. It is a cross-sectional view of a resin tube. Further, FIG. 6 is an explanatory view of a step of imparting a texture pattern to the surface of a foamed resin tube having an outer surface coated with a film-like coating resin layer, and FIG. 7 is a cross-sectional view of a textured tube having a texture pattern. Figure 8
(A) is an enlarged plan view showing an example of a textured pattern, (B) is a cross-sectional view taken along line YY of (A), and FIG. 9 is an enlarged plan view showing another example of a textured pattern.

As shown in FIGS. 1 to 3, the main raw material M ₁ for the foamed resin tube is supplied from the hopper 11 of the extruder _{1 and} is heated and kneaded in the barrel 12 by a screw to advance. Then, the foaming agent M ₂ is press-fitted from the injection port 13 provided in the middle of the barrel 12, further kneaded by heating and enters the mold 2 attached to the tip of the extruder 1, and the resin passage 22 of the die 21 at the tip is passed through. It is extruded through, and at the same time it is extruded and expands to a substantially predetermined shape, then passes through the forming device 3 to be shaped, and is cooled by the cooling device 4 to obtain a predetermined square outer cross-sectional shape and a hole H (this Resin foam F having a round hole in the example) as shown in FIG.
Is molded into a foamed resin tube T ₁ .

Next, while the foamed resin tube T ₁ passes through the crosshead die 5 attached to the tip of the extruder 1a arranged at a right angle to the traveling direction, the extruder 1
The coating resin M ₃ supplied to a and heated and melted is extruded to the outer surface thereof, and the film-shaped coating resin layer C as shown in FIG. 5 is coated on the outer surface of the resin foam F to form a foamed resin tube T ₂ Is obtained.

A foamed resin tube T ₂ having the outer surface coated with the film-shaped coating resin layer C thus obtained is
Subsequently, as shown in FIG. 6, the coating resin layer C is passed through a heating device 6 including an electric heater arranged in a tunnel shape and a hot-air generating blower, and the surface temperature of the coating resin layer C is 20 to 100 ° C. from the melting point.
After heating to a high temperature of ℃, it passes through a graining device 7, has a grain pattern on the outer surface, a pair of cylindrical grain grain rolls (grain grain imparting members) 71 arranged on the left and right, and a pair arranged above and below. The cylindrical embossing roll 72 is pressed to form an embossed pattern, cooled by the shower-blow type cooling device 8, and continuously taken by the take-up roll 9, so that the outer surface of the resin foam F has the embossed pattern. The embossed tube T ₃ provided with the film-shaped coating resin layer D is obtained.

The embossed pattern may be a quadrangular pyramid shape as shown in FIG. 7, a triangular pyramid shaped pattern as shown in FIG. 8 arranged regularly, a satin pattern or other random patterns. It may be.

The embossed tube T thus obtained
₃ is a textured pattern formed by pressing the cylindrical textured rolls 71 and 72 onto each flat surface having a square external cross-sectional shape, so that both the center portion and the ridgeline portion of each surface are Because a clear pattern is obtained and there are ridges,
Even if there is a slight pattern deviation between adjacent surfaces, it is not noticeable as in the case of having a round outer cross section.

In the above example, a cylindrical wrinkling roll is used as the wrinkle pattern imparting member, but a moving planar mesh body or belt may be used instead of the wrinkling roll. For example, in the case of a foamed resin tube having a square cross section, as in the case of the embossing roll, it is possible to dispose the net-like body (belt) that forms the left and right surfaces and the net-like body (belt) that forms the upper and lower surfaces in a back and forth manner. Since it is possible, the problems that the joints at both ends of the mesh body (belt) are not completely closed or the ends are lifted up are less likely to occur, and the mesh body (belt) may be flat.
The pressure contact of the roll is made uniform and a clear grain pattern is obtained.

[0020]

EXAMPLE An example of a method using the above-mentioned cylindrical embossing roll will be described below with reference to the drawings. 100 parts by weight of crosslinkable polyethylene (MI: 2.0), 0.3 parts by weight of talc as a cell nucleating agent, 0.1 part by weight of dibutyl lead dilaurate as a crosslinking catalyst, and 3.5 parts by weight of stearic acid amide as a cell stabilizer. Compounded, caliber 70
mm extruder hopper 11 of the extruder 1 and after kneading and melting with a screw in the barrel 12, the halogenated hydrocarbon of the volatile foaming agent is injected from the inlet 13 in an amount corresponding to a foaming ratio of 30 times, kneading and cooling. Then, the foamed resin tube T ₁ having a substantially square outer shape was molded by discharging from the die 21 attached to the tip of the mold 2.

The foamed resin tube T ₁ is cooled until the surface temperature reaches room temperature, and a linear low density polyethylene (MI:
2.0, density: 0.925, melting point: 109 ° C) and a coating resin mixed with a pigment are melt-kneaded with an extruder 1a having a diameter of 70 mm, and a film having a thickness of 100 μm from a crosshead die 5 attached to the tip of the extruder 1a. The resin foam tube T is coated with the outer surface of the foamed resin tube T _{1 at} the same time as being extruded into a circular shape, cooled once, and covered with the film-shaped coating resin layer C.
Got _two .

Then, the foamed resin tube T ₂ coated with the film-shaped coating resin layer C is passed through the heating device 6 to be heated again so that the surface temperature of the coating resin layer C becomes 135 ° C. After passing through the device 7, the cylindrical wrinkle-providing rolls 71 and 72 were pressed against each other and cooled by the cooling device 8 to obtain a wrinkle tube T ₃ . The obtained textured tube T ₃ has a clear texture pattern and no unevenness,
The coating resin layer C had no wrinkles or burrs and had a good appearance.

[0023]

As is apparent from the above description, according to the method for producing a textured tube of the present invention, a foamed resin tube having a polygonal outer cross-sectional shape in which a film-shaped coating resin layer is coated on the outer surface. For each surface, since the texture-applying member is pressed to apply the texture pattern, there are gaps between a plurality of hourglass-shaped rolls like a foamed resin tube with a circular external cross section, or both ends of a cylindrical mesh-like body. There are no gaps at both joints and neither end is raised. as a result,
The obtained embossed tube has a clear pattern with no unevenness in the central portion of each surface and the ridge portion, and is slightly inconspicuous even if the ridge portion has a slight pattern deviation.

In addition, unlike a foamed resin tube having a circular outer cross section, a drum-shaped roll or a cylindrical mesh-like roll or a flat mesh-like body or a belt is used as a grain-texturing member without using a drum-shaped roll or a cylindrical mesh-like body. Since it is used, wrinkles and burrs are less likely to occur on the outer surface due to the difference between the outer diameter of the foamed resin tube and the inner diameter of the hourglass roll or the cylindrical mesh, and the film-covered foamed resin tube can be applied with excessive force. Accidents such as cutting are unlikely to occur, and a wrinkled tube having a uniform and beautiful appearance can be continuously and stably manufactured.

Further, the cylindrical roll, the flat net-like body or the belt used as the grain-patterning member is
The device is simpler and less expensive than the case where a drum-shaped roll or a device for forming a net-like body into a cylindrical shape is required.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a manufacturing process of a foamed resin tube whose outer surface is coated with a film-shaped coating resin layer before giving a grain pattern.

2A is a vertical cross-sectional view of a die for forming a foamed resin tube, and FIG. 2B is a cross-sectional view taken along line XX in FIG.

FIG. 3 is a vertical cross-sectional view of a crosshead die that covers a film-shaped coating resin layer.

FIG. 4 is a cross-sectional view of a foamed resin tube before being coated with a coating resin layer.

FIG. 5 is a cross-sectional view of a foamed resin tube coated with a coating resin layer.

FIG. 6 is an explanatory view showing a step of imparting a grain pattern to the surface of the foamed resin tube on which the film-shaped coating resin layer is formed.

FIG. 7 is a cross-sectional view of a wrinkled tube provided with a wrinkle pattern.

FIG. 8A is an enlarged plan view showing an example of a grain pattern,
(B) is sectional drawing which followed the YY line of (A).

FIG. 9 is an enlarged plan view showing another example of the texture pattern.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Extruder 21 Spindle 5 Crosshead die 6 Heating device 7 Texture-imparting device 71,72 Texture-imparting roll (texture-pattern imparting member) 8 Cooling device C Coating resin layer D Film-form coating resin layer with texture pattern T ₁ Foaming Resin tube T ₂ Foamed resin tube provided with a resin layer T ₃ Wrinkled tube

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B29L 9:00

Claims (1)

[Claims] 1. A wrinkle pattern is formed by pressing a wrinkle pattern imparting member on each surface of a foamed resin tube having a polygonal outer cross-sectional shape in which a film-shaped coating resin layer is coated on the outer surface. Method for manufacturing textured tube.