JPH06182893A - Repairing method for nylon molded form - Google Patents

Abstract

PURPOSE:To form a molded form having excellent external appearance and sufficient mechanical strength at a repaired part by dissolving polyamide resin in solvent, coating.filling it in a damaged part of a nylon molded form, then heating the form, and repairing the damaged part of the form. CONSTITUTION:Polyamide resin for constituting a nylon molded form is dissolved in solvent such as methanol, etc., to obtain a polyamide resin solution. A damaged part of a surface of a nylon sheath is coated.filled with it. It is mounted in heating means, i.e., a heater 1 in which a resistor 11 is internally inserted along a longitudinal direction of a heater body 10 in the body 10 having a hinge 12, and heated at about 55 deg.C to volatilize the solvent. This operation is repeated several times, a periphery of the damaged part is polished by a polishing material to finish a surface of the sheath. The repaired form (nylon sheath) is repaired at the damage in which an external appearance is not apparent, and the heating temperature is about 55 deg.C to eliminate discoloring.foaming.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for repairing a nylon molded article such as a coating layer of an electric cable, a hose, or a sheath of a flexible fluid transport pipe for transporting fluid such as petroleum.

[0002]

2. Description of the Related Art Conventionally, coating layers for electric cables, hoses,
Alternatively, in a long nylon molded product obtained by extrusion molding such as a sheath of a flexible fluid transport pipe for transporting a fluid such as petroleum, slight scratches received during manufacturing or storage include scratches. It is repaired by cutting the part with a knife and finishing the surface of the part.

However, when repairing a large scratch,
If the portion including the scratch is cut off, the thickness of the nylon molded product becomes thin, which affects the characteristics or strength of the nylon molded product. Therefore, the method of cutting out the portion including the scratch cannot be adopted.

On the other hand, in the case of moldings made of polyethylene, polyvinyl chloride, etc., when repairing a large scratch,
A method is adopted in which the same material is melted by an electric iron or the like to fill the wound.

However, if the above method is adopted when repairing a nylon molded product, the polyamide resin forming the nylon molded product foams or discolors, and the nylon molded product cannot be finished beautifully. is there. Since it is heated to a high temperature, the polyamide resin in the repaired part is locally oxidatively deteriorated and there is a problem that sufficient mechanical strength cannot be exhibited.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a good appearance, and can be repaired into a molded article having a sufficient mechanical strength in the repair section. The purpose is to provide a method for repairing an item.

[0007]

According to the present invention, a polyamide resin constituting a nylon molded product is dissolved in a solvent to prepare a resin solution, and the resin solution is applied / filled on a scratched portion on the surface of the nylon molded product. Then, there is provided a method for repairing a nylon molded product, which comprises repairing a scratched portion of the nylon molded product by heating the nylon molded product after applying the resin solution to volatilize the solvent.

Examples of the nylon molded product include a coating layer for electric cables, a hose, and a sheath of a flexible fluid transport pipe for transporting fluid such as petroleum.

As the polyamide resin for repair, copolymer nylon or the like can be used.

As the solvent, methanol, trichlene or the like can be used. The heating temperature for volatilizing the solvent varies depending on the type of the solvent, but it is preferable to set the heating temperature to a temperature near the boiling point of the solvent.

[0011]

According to the method for repairing a nylon molded article according to the present invention, a resin solution obtained by dissolving a polyamide resin constituting the nylon molded article in a solvent is applied to and filled in the scratched portion to volatilize the solvent. And

Therefore, the nylon molded product is heated only to a temperature at which the solvent is volatilized. Therefore, it is possible to sufficiently prevent the nylon molded product from being discolored or foaming.

Further, since the resin solution is applied to the scratched portion, the resin can be sufficiently filled even with a scratch having a complicated shape.

[0014]

【Example】

Example A nylon sheath of a flexible fluid transportation tube having an outer diameter of 160 mm and a wall thickness of 6 mm was scratched in the longitudinal direction with a depth of 3 mm, a width of 2 mm and a length of 50 mm. The polyamide resin used for the nylon sheath was nylon 11.

On the other hand, a soluble polyamide resin CM4000 or CM8000 made of a polyamide resin copolymer is used.
28% by weight (trade name, manufactured by Toray Industries, Inc.) was added to methanol at 60 ° C. and dissolved for about 1 hour to prepare a resin solution.

This resin solution was applied and filled on the wound of the nylon sheath. This is installed in heating means, that is, in the heater 1 in which a plurality of resistors are inserted along the longitudinal direction of the heater body 10 in the heater body 10 having the hinge portion 12, as shown in FIG. The solvent was volatilized by heating at about 55 ° C. for about 10 hours. At this time, the scratches are small but remain because the volume of the resin solution is reduced by volatilization of the solvent. Therefore, the above operation was repeated 4 times.

After that, the periphery of the scratched portion was polished with an abrasive to polish the surface and finish. The repaired nylon sheath had its scratches repaired so as to be inconspicuous, and had a good appearance without discoloration or foaming because the heating temperature was as low as about 55 ° C.

Further, a region including a repaired portion of the nylon sheath was cut out, a test piece was prepared so that the repaired portion was located at the center, and this test piece was used to JIS K 6810.
The tensile test was carried out by a method in conformity with. As a result, the test piece was broken at the chucked portion, the repaired portion was uniformly elongated, and no interfacial peeling of the filled polyamide resin was confirmed. From this, it was found that the repair part was sufficiently integrated with the nylon sheath as the base material.

Comparative Example Similar to the example, the nylon sheath of the flexible fluid transport tube was scratched. An attempt was made to repair a nylon string (same material as the nylon sheath) having a cross section of 2 mm square and a length of about 15 cm by melting it with an iron trowel heated to about 250 ° C. while pressing it against the wound. As a result, both the string and the nylon sheath, which is the base material, turned brown and foamed.

[0020]

As described above, according to the present invention, a resin solution obtained by dissolving a polyamide resin in a solvent is applied to and filled in a scratch on the surface of a nylon molded article, and the solvent is volatilized. The nylon molded product can be repaired so that it is good and has sufficient mechanical strength. Therefore, it is possible to easily repair the nylon molded product, which has been difficult in the past.

[Brief description of drawings]

FIG. 1 is a schematic view showing a heating means used in a method for repairing a nylon molded product according to the present invention.

[Explanation of symbols]

1 ... Heater, 10 ... Heater main body, 11 ... Resistor, 12 ...
Hinge part.

Claims (1)

[Claims] 1. A polyamide resin constituting a nylon molded product is dissolved in a solvent to prepare a resin solution, and the resin solution is applied / filled on the scratched portion on the surface of the nylon molded product,
A method for repairing a nylon molded article, which comprises repairing a scratched portion of the nylon molded article by heating the nylon molded article after applying the resin solution to volatilize the solvent.