JP2000006240A - Manufacture of hot melt adhesive coated thermally expansible synthetic resin tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an extremely efficient hot-melt adhesive-coated thermally expansible synthetic resin tube without problem of a decrease in adhesive properties of a hot-melt adhesive to the tube or a release of the adhesive from the tube and without losing an accuracy and reliability of the adhesion. SOLUTION: In the case of manufacturing the hot-melt adhesive-coated thermally expansible synthetic resin tube to be lined on an inner surface of a metal tube, the tubes P each having a predetermined length are butted at their ends, sent in the state that the tubes P are aligned in a straight line-like manner to an adhesive coating unit 3, continuously coated on its outer surface with a hot-melt adhesive, and a hot-melt adhesive layer is then cut by a cutter 5 to separate the tubes.

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 hot-melt adhesive-coated heat-expandable synthetic resin pipe used for producing a synthetic resin-lined pipe.

[0002]

2. Description of the Related Art In order to impart chemical resistance and corrosion resistance to a metal pipe such as a steel pipe, a heat-expandable synthetic resin pipe whose outer surface is coated with an adhesive is inserted into the metal pipe, and is heated and expanded and bonded. It is well known how to apply a synthetic resin lining by using a hot-melt adhesive as an adhesive. Since it does not contain a solvent, there is no risk of environmental pollution, explosion, etc. due to the solvent. It is suitable for coating a resin tube for use.

Conventionally, to coat the hot-melt adhesive on the heat-expandable synthetic resin tube, the outer surface of the heat-expandable synthetic resin tube may be coated with the hot-melt adhesive by melt coating using a crosshead die or the like. However, in order to obtain a hot-melt-adhesive-coated synthetic resin finger tube coated with a predetermined length of hot melt adhesive, the following two methods are conceivable. (1) A method of cutting a heat-expandable synthetic resin tube to a predetermined length and coating a hot-melt adhesive one by one in a batch. (2) A method in which a hot-melt adhesive is continuously coated on a heat-expandable synthetic resin tube as it is, and then cut into a predetermined length.

[0004]

However, in each case, there are the following problems. In the case of (1), 1
It is troublesome to coat in batches one by one and the work efficiency is not good.In addition, depending on the storage condition after cutting and before coating with hot melt adhesive, hot melt adhesive due to contamination of the heat-expandable synthetic resin tube There is a possibility that there will be a problem with the quality, such as a decrease in the adhesiveness between the resin tube and the heat-expandable synthetic resin tube, and peeling. In the case of (2), if the hot melt adhesive is coated in accordance with the extrusion speed at the time of making the heat expandable synthetic resin tube, the temperature of the hot melt adhesive is greatly reduced and the hot melt adhesive is heat expanded. Although it is difficult to coat the synthetic resin pipe uniformly and firmly, when cutting the heat-expandable synthetic resin pipe further, chips are generated and mixed with the coated adhesive, and the precision and adhesion of the adhesive are improved. Sometimes lost reliability.

The present invention has been made in order to solve such problems, and does not cause problems such as a decrease in adhesion between the hot-melt adhesive and the heat-expandable synthetic resin tube, separation, and the like. An object of the present invention is to provide a method for manufacturing a hot-melt-adhesive-coated heat-expandable synthetic resin tube that is extremely efficient without losing the accuracy and reliability of bonding.

[0006]

The present invention has solved the above problems as follows. That is, when manufacturing a hot-melt adhesive-coated heat-expandable synthetic resin tube for lining the inner surface of a metal tube, a predetermined length of the heat-expandable synthetic resin tube is abutted at its ends, and aligned in a straight line. The hot-melt adhesive is continuously fed to the adhesive coating device, coated with the hot-melt adhesive, then cut off the hot-melt adhesive layer to separate the heat-expandable synthetic resin tubes from each other. Manufactures synthetic synthetic resin tubes.

[0007]

Embodiments of the present invention will be described below with reference to the drawings based on embodiments.

FIG. 1 is a schematic front view of the entire hot melt adhesive coating apparatus used for carrying out the present invention, and FIG.
It is an enlarged plan view of the adhesive coating device shown in FIG.

As shown in FIGS. 1 and 2, a hot-melt adhesive coating apparatus includes a heat-expandable synthetic resin pipe P having a predetermined length.
Machine 1 for aligning the heat-expandable synthetic resin pipes P to send them downstream, and a heat-expanding device An adhesive coating device 3 for continuously coating the outer surface of the synthetic resin pipe P with the hot melt adhesive; a pressing device 4 provided downstream of the adhesive coating device 3 for pressing the coated hot melt adhesive; A cutting machine 5 provided on the downstream side of the pressing device 4 to cut the hot melt adhesive layer at the butt end of each heat-expandable synthetic resin pipe P to separate the heat-expandable synthetic resin pipes from each other. ing. As shown in FIG. 2, the adhesive coating device 3 includes a crosshead die 32 into which a heat-expandable synthetic resin pipe P is fed from the take-up machine 2, and an extruder 3 that supplies a hot-melt adhesive or the like to the die 32.
1 and so on. In this embodiment, two extruders 31 for the inner layer and the outer layer are connected to the crosshead die 32 via a pipe.

As the pressing device 4, a device is used in which pressing rolls are provided at appropriate intervals along the periphery of a heat-expandable synthetic resin tube P coated with a hot melt adhesive, and these are moved in the radial direction. You.

Next, the operation of the hot melt adhesive coating apparatus will be described.

The heat-expandable synthetic resin pipes P of a predetermined length are arranged on the aligning machine 1 such that their ends are aligned with each other in a straight line. The heat-expandable synthetic resin pipe P may be a pipe made in advance or a pipe extruded and molded on the same line and cut into a predetermined length. The heat-expandable synthetic resin pipe P arranged in a straight line is taken up by the take-up machine 2 and sent to the adhesive coating device 3. In the adhesive coating device 3, as shown in FIG. 2, the hot melt adhesive extruded from the extruder 31 is continuously coated on the outer surface of the heat-expandable synthetic resin pipe P via the crosshead die 32.

The hot melt adhesive used at this time includes ethylene-vinyl acetate copolymer, polyethylene,
Polypropylene, ethylene-acrylate copolymer, polyolefin resins such as ionomer resins and their modified resins, polyamide resins, polyester resins,
Further, those based on one or a mixture of two or more of butyl rubber, styrene-isoprene copolymer, styrene butadiene copolymer, polyisobutylene and the like can be mentioned.

For these raw materials, the adhesiveness is improved.
Tackifiers such as rosins, polyterpene resins, aliphatic hydrocarbon resins, aromatic hydrocarbon resins, phenolic resins, styrene resins, and coumarone indene resins for the purpose of adjusting the melt viscosity, etc., microcrystalline wax And waxes such as low molecular weight polyethylene wax, fillers such as calcium carbonate, barium sulfate, clay talc and titanium oxide.

After the hot-expandable synthetic resin tube P is coated with the hot-melt adhesive and passed through the pressing device 4, the hot-melt adhesive is firmly adhered to the outer surface of the heat-expandable synthetic resin tube P. Next, the cutting machine 5 cuts the hot-melt adhesive layer at the butt end of each heat-expandable synthetic resin pipe P to separate the heat-expandable synthetic resin pipes from each other. Thus, a hot-melt adhesive-coated heat-expandable synthetic resin tube is manufactured.

[0016]

Since the present invention is configured as described above, the following effects can be obtained. That is, according to the method of the present invention, without causing a problem such as a decrease in adhesion or peeling between the hot melt adhesive and the heat-expandable synthetic resin tube, without losing adhesion and reliability, An extremely efficient hot-melt adhesive-coated heat-expandable synthetic resin tube can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic front view of the entire hot melt adhesive coating apparatus used for carrying out the present invention.

FIG. 2 is an enlarged plan view of a main part of the adhesive coating device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aligner 2 Take-up machine 3 Adhesive coating device 31 Extruder 32 Crosshead die 4 Pressing device 5 Cutting device P Heat-expandable synthetic resin pipe

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H024 EA02 EC01 ED04 ED06 ED07 EE06 4F211 AD03 AD05 AD12 AD34 AG03 AG08 SA13 SC03 SD04 SG01 SH16 SH21 SN13 SN19 SP20 SP21

Claims (2)

[Claims] When manufacturing a hot-melt adhesive-covered heat-expandable synthetic resin tube for lining the inner surface of a metal tube, a predetermined length of the heat-expandable synthetic resin tube is abutted with each end thereof, It is sent to the adhesive coating device in a state where it is arranged in a line, and after the outer surface is continuously coated with the hot melt adhesive, the hot melt adhesive layer is cut to separate the heat-expandable synthetic resin tubes. A method for producing a hot-melt adhesive-coated heat-expandable synthetic resin tube. 2. The heat-expandable hot-melt-adhesive coating according to claim 1, wherein the outer surface of the heat-expandable synthetic resin tube is continuously coated with a hot-melt adhesive, and then the surface is pressed. A method for manufacturing a synthetic resin tube.