JPS6232825Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a thermoplastic resin-coated corrosion-resistant iron wire to be used as a wire mesh used underwater, particularly in the sea, or for applications requiring weather resistance, and uses polyamide resin with low water absorption as the thermoplastic resin coating, and , is characterized by firmly adhering this coating to the core iron wire with an adhesive. Most of the thermoplastic resin-coated anti-corrosion iron wires, etc. that have traditionally been used for wire mesh, etc., are coated with soft or medium-hard vinyl chloride resin, and are widely used for general fences, lock nets, etc. It has been used for many years, but in recent years, as marine development has been actively promoted in various parts of the country in line with the national circumstances of our country, its use has expanded in this field as well, with a focus on underwater fences, cages for aquaculture, etc. The demand continues to increase. However, when used underwater, it is exposed to harsh natural conditions that cannot be encountered during normal land use, such as abrasion of the coating due to quicksand caused by tidal currents, and damage to the wire rods due to waves, etc. Abrasion or crushing peeling of the coating due to tangling or squeezing, destruction of the coating due to collision with drifting objects, ships, anchors, etc., have become evident as problems with soft to medium-hard vinyl chloride-coated iron wire. In addition to these film failures that occur after immersion in the sea, the film may be mechanically damaged during secondary processing after the wire coating process, such as wire mesh processing, selvedge processing, or connection processing between wire meshes. There are also many injuries sustained. All of these scratches on the film before and after immersion in the sea become points for seawater to enter the film, causing corrosion of the core wire and
This may cause wire breakage. Particularly in aquaculture fisheries, cages made of soft or medium-hard vinyl chloride-coated iron wire are becoming more widespread due to concerns about contamination of aquaculture fish by zinc in galvanized wire cages that have been used since the beginning, and from the viewpoint of extending the life of the cage itself. Accidents often occur in which farmed fish are lost overnight due to breakage due to the above-mentioned failures, and there is a strong desire to improve the overall anti-corrosion function with a focus on the mechanical strength of the coating. The present inventor focused on this point, and as a result of various studies on extrusion anti-corrosion coating of iron wire with crystalline engineering plastics with excellent mechanical properties, we found that homopolyamide resins, such as polyamide 11, polyamide
12, polyamide 612 or a multi-component polyamide copolymer using these monomers, such as polyamide 6/
12. Coating the iron wire with polyamide resin such as polyamide 6/66/12 or a mixture of a monopolymer and a polyamide polymer having intermediate compatibility thereof, such as a mixture of polyamide 12 and polyamide 6/12 to a thickness of 70μ or more. . More preferably, an adhesive or anticorrosion paint based on polybutadiene rubber or (and) epoxy phenol resin is used as the primer,
Strongly adheres polyamide film to iron wire. For example, a primer made of polybutadiene rubber as a base material (for example, a primer prepared by mixing a polymer compound obtained by polymerizing a diene compound disclosed in Patent Application No. 33229 of 1975 with magnesium oxide, or a primer made of a mixture of magnesium oxide and A primer made by mixing a polymer compound obtained by polymerizing a diene compound disclosed in 1950 Patent Application No. 116099, magnesium oxide, and cobalt ions and/or manganese ions)
Polyamide is added to the baked iron wire for water resistance.
12 or a mixture of polyamide 12 and polyamide 6/12, that is, a caprolactam/laurinlactam copolymer, is coated with a thickness of 150 μm or more by extrusion molding, and at the same time, the coating is adhered to the core wire. The anticorrosive iron wire of the present invention is suitable for use underwater, particularly in seawater, and the polyamide resin has a saturated water absorption rate (water temperature of 20°C) of 5% or less, preferably 3% or less, such as nylon. 11
(1.9%), nylon 12 (1.5%), nylon 6/12
(3%) etc. There are also copolymers and mixtures with homopolymers containing these monomers as main components. It has been found that the present invention significantly improves many of the drawbacks of the above-mentioned soft to medium-hard vinyl chloride-coated corrosion-resistant iron wire. At this time, if the iron wire forming the core wire is galvanized and then coated with the above resin,
A more preferable primer is obtained from the viewpoint of corrosion prevention, and the primer used at this time is one based on epoxy phenol resin (for example, 70 to 80 parts by weight of epoxy resin and novolac resin disclosed in Patent Application No. 121896 of 1975). Type alkylphenol resin 30~
20 parts by weight of primer and 1.25 to 2.5 parts by weight of acid catalyst) give good results. In the present invention, the use of a weathering stabilizer for the purpose of improving the weather resistance of the polyamide film, or the use of coloring it black or the like, does not pose any problem to the present invention. The core iron wire referred to herein includes not only round rod, square rod, and wire shapes, but also belt-shaped wires, pipe, and tube-shaped wires. The reason why films made of polyamide resin have excellent anti-corrosion properties is that in addition to the strong mechanical strength and excellent friction and wear properties of the polyamide resin itself,
50 to 100 on the outer surface of the film by water cooling during extrusion coating.
A skin layer with a low crystallinity and high elasticity is formed with a thickness of about μ, and the entire film has a structure in which a buffer zone against external impact is provided on the deep layer of the film, which has a high crystallinity and is rich in hardness. Moreover, because the deep layer with high hardness is firmly bonded to the core wire, there is no slippage between the coating and the core wire when external loads are applied, and the coating is extremely resistant to peeling. This is because it is in a safe condition. Furthermore, it is usually extremely difficult to reliably prevent corrosion within the core wire coating due to minute amounts of water and oxygen that permeate through the coating, whether it is soft vinyl chloride coating or polyamide coating. In the coating of this invention, the primer layer that is firmly adhered to the core wire acts as an insulator and prevents iron from ionizing, thereby preventing corrosion from progressing within the coating. Even if a scratch occurs, the coating and the core wire are bonded together, which reliably prevents seawater from further penetrating into the interface between the core wire and the coating, which is the reason why the coating's anti-corrosion function is further strengthened. Furthermore, a particularly notable feature of the polyamide coating of the present invention is that it is much easier to remove marine organisms that adhere to and propagate on the coating after immersion in seawater, compared to soft or medium-hard vinyl chloride coatings. This characteristic is extremely important in cages for aquaculture. This is because the wire mesh used for aquaculture fishing cages is constantly filled with food, making it an extremely fertile medium, and the surrounding seawater itself is also rich in nutrients due to feeding and the excrement of farmed fish. . Therefore, the growth of algae or shellfish attached to the wire mesh is abnormally fast and the wire mesh becomes clogged in a very short period of time, so if left as is, the inside of the cage will become oxygen deficient and the cultured fish will die. As a countermeasure to this problem, adding an antifouling agent to the film was considered, but it was not very effective, and it also caused contamination and chemical damage to farmed fish, so there were few examples of this being put to practical use. Therefore, the reality is that aquaculture farmers regularly have divers dive around the cages, for example 2 to 4 times a month during the breeding season from April to October, to remove organisms that have grown attached to the wire mesh. In addition, in the case of soft vinyl chloride coatings, these organisms are extremely attached, so it is inevitable to damage the coating during removal work, reducing the lifespan of the living organisms and increasing costs due to low efficiency. This increase was placing a heavy burden on fish farmers. On the other hand, polyamide films are similarly powerless against the propagation of marine organisms, but
Since its removal is much easier than with soft vinyl chloride coatings, it improves efficiency and eliminates the need for strenuous work that would damage the coating itself. It can be extremely effective in preserving the living space and prolonging its life. It is currently unclear what properties of the polyamide film are responsible for the characteristics of the polyamide film against marine life, but the polyamide coating has a smooth surface that is far superior to that of soft or medium-hard vinyl chloride coatings. It is thought that the advantages include that it has excellent resistance to secretions from sea creatures, and that the film surface is stable without deterioration because there are no eluted components such as plasticizers. As described above, the polyamide resin adhesive coated anti-corrosion steel wire according to the present invention significantly improves the anti-corrosion function of the conventional soft or medium-hard vinyl chloride coated anti-corrosion steel wire, and has an excellent effect on extending the life of structures made of steel wire underwater. At the same time, it greatly contributes to the reduction of conservation costs, and should be used preferentially especially in applications where the propagation of marine organisms is a problem, such as cages for fish farming. The polyamide adhesive extrusion coated wire of the present invention has a cross-sectional structure as shown in FIG. 21 is an iron wire, 22 is a primer layer, and 23 is a polyamide layer. Its uses include submarine cables, armored iron cables,
Fishing cages, underwater fences (for preventing floating objects, e.g. to prevent jellyfish from entering near seawater intakes at nuclear power plants), rock nets, various coils for use outside the layer (e.g. catenary hangers), springs, wire ropes (parallel ropes, etc.) (used for the main rope of tree bridges), form wire, and sieves (sieves for granular materials containing seawater or fresh water). Can be applied to various required wires. Example 1 A soft iron wire with a wire diameter of 3.2 mm (no rust) was degreased by washing with trichlene, and then a polybutadiene primer (manufactured by Daicel Chemical Industries, Ltd., trade name, F-1-D) was applied to a thickness of 10 to 10 mm. It was applied to 30μ and baked in an electric furnace at 350°C for 15 minutes. Subsequently, while maintaining the iron wire temperature at 200℃, polyamide resin was extruded to a thickness of 400℃ at a wire speed of 30m/min using an extruder with a screw diameter of 40mm equipped with a crosshead die.
μ was coated and simultaneously cooled continuously in a water cooling bath. The results of the film strength evaluation test of the polyamide resin adhesive coated iron wire thus obtained are shown in Table 1 together with the film strength evaluation test results of the commercially available medium hard vinyl chloride coated iron wire having the same core wire diameter and film thickness.

【table】

[Table] Example 2 Table 2 shows the results of a water resistance evaluation test of a polyamide-coated iron wire manufactured in the same manner as in Example 1 and a commercially available medium-hard vinyl chloride-coated iron wire having the same core wire diameter and coating thickness.

【table】

【table】 [Brief explanation of the drawing]

FIGS. 1, 2, and 3 are diagrams showing a test method for the coated anti-corrosion iron wire of the present invention, and FIG. 4 is a sectional view of the coated anti-corrosion iron wire of the present invention. 21... Iron wire, 22... Primer layer,
23...Polyamide layer.

Claims (1)

[Scope of utility model registration request] A polyamide resin made of polyamide 11, polyamide 12, polyamide 612, or a copolymer or mixture containing these as main components is interposed on the core iron wire with a primer layer based on polybutadiene rubber or (and) epoxy phenol resin. A polyamide resin-coated corrosion-resistant iron wire made by extrusion molding and bonding the coating.