JP2000179789A - Heat reserving tube and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conform a fin part to the surface of cylindrical heat insulating material to stably cover a cut part by making the thickness of a base part in the fin part for covering the cut part, thinner than the parts other than the base part in a heat reserving tube formed by coating the outer surface of the cylindrical heat insulating material with the cut part, with the outer skin formed of synthetic resin. SOLUTION: A coating resin passage 4 is formed in a heat reserving tube manufacturing device by an outer mold 1, a lip 2 and a core 3. Cylindrical heat insulating material 6 is formed and led into a tube protecting pipe 5. Resin mixed with a coloring agent is extruded, and when the resin comes out of a lip 2, the surface of the cylindrical heat insulating material 6 is coated with the resin to form the outer skin 7. Resin for a fin part is extruded from a metal mold slit 23, and when the resin comes out of the lip 2, a wire 8 is pressed from both sides of a base part 72 of a fin part 71 to press the base part 72 to thin its thickness. The vicinity of the fin part 71 of the cylindrical heat insulating material 6 is longitudinally slit to form a cut part, and then cooled with water discharge to complete a heat reserving tube.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat retaining tube which is provided on a pipe such as a water pipe or a hot water supply pipe, and a method for producing the same.

[0002]

2. Description of the Related Art A heat retaining tube is provided on a pipe such as a water pipe or a hot water supply pipe for heat insulation. As this kind of heat retaining tube, an outer surface made of a synthetic resin is coated on the outer surface of a cylindrical heat insulating material having a cut portion in which a part of a cross section is cut in a longitudinal direction, and a fin portion for covering the cut portion is provided. A fin is used in which an adhesive layer and a release paper are laminated on one side.

As shown in a perspective view in FIG. 4, such a heat retaining tube has a fin 7 for covering the cut portion 62 on the outer surface of a cylindrical heat insulating material 60 having a cut portion 62 in the longitudinal direction.
3, coated with a soft polyvinyl chloride skin 70 having
The release paper 91 is laminated on the surface of the adhesive layer 9 of the fin 73.

The fin portion 73 of the conventional heat insulating tube is perpendicular to the upper cylindrical heat insulating material 60, and the base portion 74 of the fin portion 73 and the portion other than the base portion are formed with the same thickness.
The base 74 is formed slightly thicker. For this reason,
The pipe is passed through the heat retaining tube and the cut portion 6 is formed at the fin 73.
When coating 2, the rigidity of the base 74 of the fin 73 may cause the base to rise without being adapted to the surface of the cylindrical heat insulating material, or the base 74 may float and gradually peel off.

Further, since the fins 73 are raised, if a plurality of such heat retaining tubes are stored in one packing box, the raised fins 73 are rubbed and fins 7 are rubbed.
The release paper 91 stuck on 3 may be turned up.

As a method for avoiding the above phenomenon,
While the resin temperature of the molded fin does not decrease, a method is conceivable in which the fin is pressed against the tubular heat insulating material from the outside with a pressing plate or the like to give a bending habit. However, it is not practical because there is a problem that the softened resin adheres to the holding plate or the like and the appearance of the held fins deteriorates. After the fins have been cooled, even if they are held down by a holding plate or the like, deformation is recovered over time after opening, so there is no effect.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and has a fin portion which fits well into the surface of a tubular heat insulating material, and which can stably cover a cut portion and a method of manufacturing the same. The purpose is to provide.

[0008]

According to the heat insulating tube of the present invention, the outer surface of a cylindrical heat insulating material having a cut portion whose cross section is partly cut off in the longitudinal direction is coated with a skin made of synthetic resin, In the heat retaining tube provided with a fin for covering the fin, the thickness of the base of the fin is made thinner than the portion other than the base of the fin.

The method for manufacturing a heat insulating tube according to the present invention is also directed to a cylindrical heat insulating material in which a long synthetic resin foam sheet is deformed in the width direction while being transported in the longitudinal direction to be cylindrical, and the edges are bonded to each other. The cylindrical heat insulating material is introduced into a mold connected to an extruder, and the surface of the cylindrical heat insulating material is coated with a molten thermoplastic resin supplied to the mold from the extruder. In a method of manufacturing a heat retaining tube for forming a hanging fin at a lower portion of a material and cutting a tubular heat insulating material in the vicinity of the fin in a longitudinal direction, while the resin of the fin is in a softened state, a thickness of the base of the fin is reduced. The thickness of the base is reduced by pressing in the direction.

As the tubular heat insulating material used in the present invention, those conventionally used as heat insulating tubes can be used.
Among them, those formed of a foam of a polyvinyl chloride resin or a polyolefin resin are preferable. Further, the synthetic resin that covers the outer surface of the cylindrical heat insulating material and forms the fins is preferably an extrudable thermoplastic resin, and the thermoplastic resin is preferably a thermoplastic elastomer or a polyolefin-based resin. Polyvinyl chloride resin, chlorinated polyvinyl chloride resin and the like can also be used.

The base of the fin refers to a part separated from the outer skin as a fin and the vicinity thereof, and a range of about 10 mm from the outer skin in the width direction of the fin. The thickness of the base of the fin is 1 / 1.1 of the thickness of the part other than the base of the fin.
The range is about 3 to 1/5. If the thickness of the base of the fin is less than 1/5 of the thickness of the part other than the base, the strength of this part is low and it is easy to tear. If the thickness exceeds 1 / 1.3, it is difficult to bend and the cut part is covered stably. Is difficult. The thickness ratio between the base of the fin and the portion other than the base is in the above range, and the thickness of the portion other than the base is preferably in the range of 50 to 300 μm, more preferably 70 to 25.
0 μm.

As a method for reducing the thickness of the base of the fin, a base having a small thickness can be formed by narrowing a mold outlet corresponding to the base at a portion where the fin exits the mold. When using a conventional mold for manufacturing a heat retaining tube having a fin, when the fin comes out of the mold, two metal plates, wires, etc. having a distance corresponding to the thickness of the base at a position corresponding to the base. The thickness of the base can be reduced by allowing the fins to pass while pressing with a metal plate or wire while the fin is in a molten or softened state.

(Function) Since the base of the fin is thinner than the base other than the base of the fin, the heat-retaining tube of the present invention is easily bent from the base, the rigidity of the base is extremely small, and the tubular shape is obtained. It does not rise from the insulation. Also, the packing condition is stabilized. According to the method for manufacturing a heat retaining tube of the present invention, the base thickness of the fin can be reduced at the same time as the formation of the fin, and the production can be performed efficiently.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment) FIG. 1 is an upper half sectional view showing an apparatus used for manufacturing a heat retaining tube of the present invention, and FIG. 2 is a sectional view taken along line II-II of FIG. 1 and 2, the outer mold 1
A coating resin flow path 4 is provided between the lip 2 and the core 3. Reference numeral 21 denotes a thickness adjustment bolt, reference numeral 22 denotes a holding ring, and reference numeral 5 denotes a tube protection tube. One end of the wire 8 is fixed to both sides of a mold slit 23 provided below the lip 2 by a fixing tool 81, and is arranged so that the interval between the tips of the wires 8 on both sides is 50 μm.

A cross-linked polyethylene foam sheet having an expansion ratio of 30 and a thickness of 10 mm was slit into a predetermined width and heated to form a tubular heat insulating material 6 having an outer diameter of 49 mm.
Was introduced into the tube protection tube 5. Next, linear low-density polyethylene (MI = 16, density 0.920) and ethylene-vinyl acetate copolymer (MI = 16, density 0.940)
And a colorant in a ratio of 1: 1 to 100 parts by weight of a resin.
The resin blended in parts by weight was extruded at a rate of 32 kg / hr by a single screw extruder (50 mmφ, not shown). When the resin came out of the lip 2, the surface of the cylindrical heat insulating material 6 was coated with a thickness of about 150 μm to form a shell 7. At the same time, the resin was extruded from the mold slit 23 provided at the lower part of the lip 2 to form a fin with a thickness of 150 μm and a width of 50 mm. When the fin resin came out of the lip 2, the wires 8 provided on both sides of the mold slit 23 were pressed from both sides of the base 72 of the fin 71, and the base 72 was pressed to a thickness of 50 μm. Next, the vicinity of the fin 71 of the tubular heat insulating material 6 on which the outer skin 7 was laminated was slit in the longitudinal direction to form a cut portion, and then cooled by discharging water to obtain a heat retaining tube of the present invention. In the above extrusion process, the extruded resin temperature was about 145 ° C., the line speed was 20 m / min, and the cooling water temperature was 23 ° C.

FIG. 3 is a perspective view showing the obtained heat retaining tube of the present invention, in which the fin 71 is slit to a width of 35 mm, and the surface covering the cut portion 61 of the tubular heat insulating material 6 is subjected to conventional adhesive processing. The release paper 92 is laminated on the pressure-treated surface.

Even if a plurality of heat retaining tubes having the fins were put in one cardboard box, each fin was bent from the base and could be stored in a stable state. Further, even when the cut portion of the tubular heat insulating material was covered, the fin portion did not rise, and a stable covered state could be maintained for a long time.

[0018]

The thickness of the base of the fin is smaller than the thickness of the part other than the base of the fin, so that it is easily bent from the base, the rigidity of the base becomes very small, and the base rises from the cylindrical heat insulating material. In addition, it fits well into the surface of the tubular heat insulating material, and can stably cover the cut portion. Also, the packing condition is stabilized. Further, according to the method for manufacturing a heat retaining tube of the present invention, the base thickness of the fin is reduced at the same time as the formation of the fin, so that the tube can be manufactured efficiently.

[Brief description of the drawings]

FIG. 1 is an upper half sectional view showing a main part of an apparatus for manufacturing a heat retaining tube of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a perspective view showing an embodiment of a heat retaining tube of the present invention.

FIG. 4 is a perspective view showing a conventional heat retaining tube.

[Explanation of symbols]

 1: outer mold 2: lip 3: core 4: coated resin flow path 5: tube protection tube 6, 60: tubular heat insulating material 7, 70: outer skin 8: wire 9: adhesive layer 23: mold slit 71, 73: Fins 72, 74: Base 81: Fixture 91, 92: Release paper

Claims (2)

[Claims] 1. An outer surface of a cylindrical heat insulating material having a cut portion in which a part of a cross section is cut in a longitudinal direction is covered with an outer cover made of synthetic resin, and a fin portion for covering the cut portion is provided. A heat insulation tube according to claim 1, wherein the thickness of the base of the fin is smaller than the thickness of the part other than the base of the fin. 2. A long-sized synthetic resin foam sheet is deformed in the width direction while being transported in the longitudinal direction to form a cylindrical shape, and the edges are adhered to each other to form a cylindrical heat-insulating material. Introduced into a mold connected to the extruder, and coated the surface of the cylindrical heat insulating material with the molten thermoplastic resin supplied to the mold from the extruder, and formed a fin portion hanging down at the lower portion of the cylindrical heat insulating material. ,
In the method of manufacturing a heat insulating tube for cutting a tubular heat insulating material in the vicinity of a fin in a longitudinal direction, while the resin of the fin is in a softened state, the base of the fin is pressed in a thickness direction to reduce the thickness of the base. A method for manufacturing a heat retaining tube, characterized in that the tube is thinned.