JPH0519459B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a method for anticorrosion coating the surface of metal materials including steel materials such as steel sheet piles, steel pipe piles, and steel pipes.

[Background of the Invention] For the purpose of corrosion prevention on the surface of metal materials such as steel or aluminum pipes or plate-shaped molded bodies, adhesive coating of a plastic coating sheet such as a polyolefin coating sheet on the surface has already been practiced.

In particular, steel sheet piles or steel pipe piles are often used in contact with seawater for purposes such as seawalls, and are required to have long-term durability under such harsh conditions. It is used with anti-corrosion coating with polyolefin layer.

Generally, a sheet or film made of polyolefin resin or the like is used for such anti-corrosion coating. However, since polyolefins do not have polar groups and have poor adhesion to metal materials, adhesives containing polar groups such as maleated modified polyolefins that develop adhesion to metal materials when heated A polyolefin coated sheet, in which a layer is previously arranged on one side of the polyolefin sheet and laminated thereon, is generally used as the coating material. Such a polyolefin coated sheet is attached to the surface to be coated with anti-corrosion by heating and fusing it. The application of the polyolefin coated sheet as described above is generally carried out in a factory, since it is necessary to heat the sheet during application.

However, depending on the shape of the object to be coated with anti-corrosion, it may not be possible to apply effective anti-corrosion coating in advance in the factory, and the welded parts may be welded on the work site, including the exposed steel pipe surface near the welded parts. Anti-corrosion coated. Furthermore, as a matter of course, it is common to repair damaged portions of the anticorrosion coating layer at the location where the damage occurred.

[Prior art and its problems] A method for anticorrosive coating of metal materials using a polyolefin coated sheet as described above includes, for example, a polyolefin coated sheet formed by laminating and fusing a heat-melting adhesive layer on one side of a polyolefin sheet. is placed so that the adhesive layer is in contact with the surface to be coated with anti-corrosion coating, such as steel material, and the polyolefin surface of this polyolefin-covered sheet is directly heated using the flame of a gas burner or hot air, so that it is in contact with the surface to be coated with anti-corrosion coating. This is carried out by a method such as softening the adhesive layer and subjecting it to heat and pressure bonding.

The above anti-corrosion coating method requires almost no other tools as long as you have a gas burner or a heat source that generates hot air, and the work is extremely simple.
This method is widely practiced because it can be easily carried out not only in factories but also at pipeline construction sites, steel pipe pile driving sites, etc.

However, the method described above directly heats the surface of the polyolefin-covered sheet to soften the heat-melting adhesive layer on the back surface to a bondable state.
There is a problem in that the surface of the polyolefin coated sheet is thermally degraded by this heating. Furthermore, when trying to apply the above method to covering steel pipe piles or steel sheet piles driven on the coast, for example, even if heated, the adhesive layer is not cooled by seawater to a softened state where it can be bonded. There are many problems, and effective attachment cannot be carried out.

On the other hand, various improvements have been proposed regarding the adhesive component of polyolefin-coated sheets.

For example, JP-A-56-143223 and JP-A-56-117642 disclose that the main feature is that an epoxy resin is applied to the surface of a metal material in advance and a modified polyolefin or polyolefin layer is heat-adhered thereto. An invention is disclosed. These methods do not require direct heating of the surface of the polyolefin layer, so the problem of thermal deterioration of polyolefin is solved, but the metal material can be heated in advance.
It is necessary to heat the material to about 150°C, and therefore even with these methods, it is not possible to effectively apply the anticorrosive coating under the conditions described above where sufficient heating cannot be performed. The problem still persists.

[Object of the Invention] An object of the present invention is to provide a method for anticorrosion coating on the surface of a metal material that does not particularly require heating.

In particular, it is an object of the present invention to provide a method for attaching a polyolefin coating sheet to steel sheet piles, steel pipe piles, steel pipes, etc. without particularly requiring heating.

[Summary of the Invention] The present invention provides a hardened resin layer on the surface of a metal material, a polyolefin-coated sheet having a hardened epoxy resin layer on the hardened resin layer, and a hardened epoxy resin layer that is the same as the hardened resin layer. As if facing each other,
After laminating with a reaction-curing resin intermediate layer,
The present invention provides a method for anticorrosion coating on the surface of a metal material, which comprises completing the curing of the reaction-curable resin intermediate layer and adhering the polyolefin coating sheet.

[Effects of the Invention] By utilizing the present invention, it is possible to apply an effective anticorrosion coating even to the surface of a metal material that is difficult to heat sufficiently.

Furthermore, since no particular heating is required when applying the anti-corrosion coating, there is no thermal deterioration of the polyolefin coated sheet due to heating, and the anti-corrosion properties are good.

[Detailed Description of the Invention] The attached FIG. 1 is a diagram showing an example of an embodiment in which a surface of a metal material is coated with an anticorrosion coating according to the anticorrosion coating method of the present invention.

Basically, in the present invention, first, a cured resin layer 12 is attached to the surface of a metal material 11 (the surface to be coated with anticorrosion), and a polyolefin coating sheet 14 having a cured epoxy resin layer 13 is separately prepared. A reaction-curable resin intermediate layer 15 is attached to the surface of this cured resin layer 12 and/or the surface of the cured epoxy resin layer 13 . Next, the polyolefin coated sheet 14 is laminated under pressure so that the epoxy resin cured layer 13 and the resin cured layer 12 face each other with the reaction curable resin intermediate layer 15 interposed therebetween, and then the reaction curable resin intermediate layer 15 is laminated.
This is an anticorrosive coating method in which the curing reaction of the polyolefin coating sheet 14 is completed and the polyolefin coated sheet 14 is adhered to the surface.

There are no particular restrictions on the metal material to which the anticorrosion coating is applied, as long as it requires an anticorrosion coating during use. Examples of such metal materials include:
Mention may be made of metal products made of iron, aluminum or zinc. In particular, the present invention is suitable for anticorrosive coating of iron steel pipe piles, steel sheet piles, and steel pipes. As mentioned above, the parts of steel pipe piles and sheet piles used for seawalls, etc. that are close to the bonded parts with seawater are cooled by seawater, so conventional methods that include heating operations cannot effectively heat them. I can't do it. Therefore, in this case, the anticorrosive coating method of the present invention is particularly useful.

Other anti-corrosion coatings, such as polyolefin anti-corrosion coatings, may be applied in advance around the area to be coated with anti-corrosion.

The polyolefin-coated sheet used in the present invention has a cured epoxy resin layer.

Epoxy resin is an adhesive with good weather resistance,
Since it shows excellent adhesion to metal materials, it can be advantageously used as an anti-corrosion coating, but on the other hand, it does not show sufficient adhesion to anti-corrosion coating sheets such as polyolefin or modified polyolefin at room temperature. . Therefore, when trying to take advantage of the excellent weather resistance of epoxy resin, the conventional method is to apply epoxy resin to the surface of the metal material, place an anti-corrosion coating sheet on top of this coating layer, and then heat them. I had to glue it together. However, in this method, sufficient adhesion cannot be achieved under conditions where sufficient heating cannot be performed, and the objective of providing excellent corrosion resistance over a long period of time cannot be achieved.

On the other hand, the present invention is a method of using a polyolefin coated sheet in which a cured epoxy resin layer is laminated in advance and integrated as an anticorrosion coating material.
This is a method for attaching a polyolefin coated sheet to a surface of a metal material to be protected against corrosion without requiring heating for adhesion to an epoxy resin.

Although a molded product of a modified polyolefin sheet can be used as the polyolefin coated sheet, generally a modified polyolefin layer 17 is laminated on the surface of an unmodified polyolefin sheet 16. In the latter case, a cured epoxy resin layer 13 is laminated on the modified polyolefin layer.

As the unmodified polyolefin sheet, those used in ordinary anticorrosion coating materials can be used. Examples of materials include low-density polyethylene;
Medium density polyethylene, high density polyethylene, polypropylene, poly-1-butene and poly-4-
Olefin homopolymers such as methyl-1-butene, ethylene/propylene copolymers, ethylene/1-butene copolymers, propylene/1-butene copolymers, ethylene/vinyl acetate copolymers, and ethylene/acrylic acid Examples include olefin copolymers such as ester copolymers, and polymeric substances obtained by crosslinking these olefin homopolymers or olefin copolymers by a known method.

Sheets formed from unmodified polyolefins such as those described above are known to have high weather resistance. In particular, polyolefin sheets containing polyethylene as a main component are advantageous because they have good weather resistance and are inexpensive.

Examples of polymers forming modified polyolefin layers include polyolefins grafted with unsaturated carboxylic acids (e.g., maleic acid, itaconic acid) or their anhydrides, and polyolefins grafted with unsaturated bonds and epoxy groups. Examples include polymers graft-modified with monomers contained in the molecule (eg, vinyl glycidyl ether, acrylic glycidyl ether, vinyl glycidyl thioether, glycidyl acrylate, glycidyl methacrylate, p-glycidyl styrene). In particular, it is preferable to use polyethylene grafted with maleic acid or its anhydride.

An example of the epoxy resin forming the epoxy resin cured layer is an epoxy resin formed from a bisphenol A base resin having an epoxy equivalent of 170 to 280 and an organic polyamine curing agent having an amine value of 200 to 500. can. Examples of the above-mentioned organic polyamine curing agents include modified aliphatic polyamines, modified aromatic polyamines, and heterocyclic modified polyamines. These can be used alone or in combination. For example, in consideration of weather resistance and adhesion to modified polyolefins, it is preferable to use a heterocyclic modified polyamine.

Examples of heterocyclic modified polyamines include: can be mentioned.

The ratio of the amount of the bisphenol A base agent to the organic polyamine curing agent used can be determined according to conventional methods.

When the polyolefin coated sheet is a modified polyolefin layer attached to an unmodified polyolefin sheet, the thickness of the unmodified polyolefin sheet is generally in the range of 0.2 to 10 mm, preferably 1 to 4 mm, and the thickness of the modified polyolefin layer is is 0.05~5
mm, preferably in the range of 0.1 to 3.5 mm.

When the polyolefin-covered sheet is made of a molded product of modified polyolefin, its thickness is generally in the range of 0.3 to 10 mm, preferably 1 to 1 mm.

The thickness of the epoxy resin cured layer is 3 to 100μ.
m, preferably in the range of 10 to 50 μm.

The production of such a polyolefin-coated sheet and the addition of a cured amount of epoxy resin are generally carried out by the following method.

For example, first, a modified polyolefin layer is attached to the surface of an unmodified polyolefin sheet such as a polyethylene sheet by a known method.

In addition, when using a crosslinked unmodified polyolefin sheet, it is also possible to laminate the modified polyolefin on a polyolefin sheet that has been crosslinked in advance, or a crosslinking operation may be performed after lamination.

After applying an uncured epoxy resin on the modified polyolefin layer of the laminated sheet (polyolefin coated sheet) obtained as described above by brush coating, spray coating, or bar coater, the modified polyolefin layer of the laminated sheet is modified. By heating the laminated sheet to a temperature above the melting point of polyolefin,
Either the epoxy resin is cured while the modified polyolefin layer is softened, or the uncured epoxy resin is applied to the laminated sheet at a temperature below the melting point by the above method, and the modified polyolefin layer and the epoxy resin are integrated while the epoxy resin is cured. A polyolefin coated sheet having a cured epoxy resin layer is obtained.

Heating for the heating operations described above can be carried out according to conventional techniques. For example, it is possible to use an infrared heater, but in order to bond and integrate the laminated layers more firmly,
For example, it is preferable to heat under pressure using a heating roll or a heating press. When using a heated roll or a heated press, it is preferable to use Teflon or the like on the contact surface with the sheet to impart releasability.

Note that even when using a sheet made only of modified polyolefin, it can be manufactured according to the above method.

It goes without saying that the polyolefin (modified or unmodified) sheet may contain additives that are normally contained (eg, antioxidants, pigments, and other additives).

An uncured reaction-curable resin intermediate layer 15 is attached to the surface of the above-mentioned cured epoxy resin layer 13 .

The resin forming the reaction-curable resin intermediate layer is a resin that has adhesive properties between the cured epoxy resin layer and the cured resin layer at room temperature.

Examples of resins used include epoxy resins and polyurethane resins. In particular, it is preferable to use polyurethane resin. Ordinary polyurethane resins can be used.

In addition, when using an epoxy resin, it is necessary to select and use a resin that has good adhesion to both the epoxy resin cured layer and the reaction-curable resin layer.

The reaction-curable resin intermediate layer is applied to the surface of the epoxy resin cured layer 13 in an uncured state by a method such as coating, and is applied to the surface of the metal material 11 in an uncured state (including a partially cured state). is pressed so as to be in contact with the resin cured layer 12 attached to the surface.

Note that the reaction-curable resin intermediate layer 15 described above is the epoxy resin cured layer 1 on the polyolefin-coated sheet side.
Instead of being attached to the surface of 3, it may be attached to the surface of the resin hardening layer 12 attached to the metal material. Alternatively, the reaction-curable resin intermediate layer 15 may be attached to both the surface of the epoxy resin cured layer 13 and the surface of the resin cured layer 12.

The thus produced polyolefin coated sheet is placed on the resin cured layer 12 formed on the surface of the metal material 11 to be coated with anti-corrosion, and the epoxy resin cured layer 13 and the resin cured layer 12 are placed between the reaction hardening resin intermediate layer 13 and the resin cured layer 12. They are laminated so as to face each other with the layer 13 in between, and then bonded.

The hardened resin layer 13 can be applied to the surface of the metal material 11 by using a conventional method such as brushing or spraying a resin as described below.

That is, for example, when using a thermoplastic resin described below, it is cured by heating or by dissolving it in a solvent and applying it. Further, a thermosetting resin or a reaction-curing resin is dissolved in a solvent or applied to a metal surface without using a solvent, and then heated or a reaction is allowed to proceed to a hardened state.

Note that the resin hardening layer can be applied at the work site, or can be applied in advance in the factory. Furthermore, it is advantageous to add a hardened resin layer to the metal material to prevent corrosion when the metal material is left outdoors and stored.

The thickness of this resin cured layer is generally 3 to 100 μm.
m, preferably 10 to 50 μm.

The resin forming the cured resin layer is a resin (non-polyolefin resin) excluding polyolefin resin that does not exhibit adhesiveness to both the metal to be coated with anti-corrosion and the reaction-curing resin intermediate layer. Thermoplastic resins, thermosetting resins and reaction curable resins can be used. Therefore, polyolefin resins such as polyethylene resins cannot be used because they have poor adhesion to the metal surface to be protected from corrosion and the reaction-curing resin intermediate layer.

Among non-polyolefin resins, it is particularly preferable to use resins having polar groups. Here, the resin having a polar group refers to, for example, a resin manufactured using at least one type of monomer having a polar group when manufacturing the resin, a resin modified with a substance having a polar group, or a resin having a polar group. Refers to a resin that is mixed with a resin that has

Furthermore, it is preferable to use a resin that has a substantially polar group and includes a nitrogen atom and/or an oxygen atom in the resin structure.

Examples of thermoplastic resins that satisfy the above conditions include polyamide resins, polycarbonate resins, and acrylonitrile resins.

Examples of thermosetting resins include polyester resins, polyimide resins, melamine resins,
Mention may be made of urea resins and phenolic resins.

Furthermore, examples of reaction-curable resins include epoxy resins and polyurethane resins.

Among the above-mentioned resins, reaction-curing resins and thermosetting resins are particularly preferred, and reaction-curing resins that satisfy the above conditions are particularly preferred because they have good weather resistance. Furthermore, among reaction-curing resins, epoxy resins are outstanding in terms of weather resistance.

When using an epoxy resin as the reaction-curing resin for forming the resin cured layer 12, it is particularly preferable to use the same epoxy resin as the epoxy resin forming the epoxy resin cured layer forming the polyolefin coated sheet described above. .

When an epoxy resin is used as the resin for the resin cured layer attached to the surface of the metal material, it is particularly preferable to use a heterocyclic modified polyamine or an aromatic modified polyamine as the organic polyamide curing agent.

There is no particular restriction on the method of laminating the polyolefin coated sheet onto the cured resin layer 12, and a normal method may be used, such as using an elastic member or the like to press and adhere the polyolefin coated sheet to the surface to be coated with anti-corrosion. can. Note that when adhering the polyolefin-covered sheet, it is not necessary to apply particular heat; however, in order to accelerate the curing of the reaction-curable resin intermediate layer, the surface of the polyolefin-covered sheet may be heated to, for example, about 50 to 60°C. It can also be heated.

The polyolefin coated sheet 14 having the epoxy resin cured layer 13 laminated in contact with the resin cured layer 12 via the reaction-curable resin intermediate layer 15 is firmly bonded by the completion of curing of the resin. be integrated.

Next, examples of the present invention will be shown.

Example 1 Steel pipe piles (diameter
After sandblasting the surface of the area corresponding to the tidal splash zone (508 mm, wall thickness 9 mm), the surface was coated with bisphenol A type (epoxy equivalent, 190) and heterocyclic modified polyamine (Yuka Ciel Epoxy Co., Ltd.). An epoxy resin consisting of Epomate B-001 (manufactured by ), amine value: 280) was applied to a coating thickness of about 40 μm, and then cured.

Separately, 2 mm thick low-density polyethylene (MI: 0.1
Prepare a sheet (carbon concentration: 2.5% by weight) of maleated polyethylene (MI: 1.5 g/10 min, density: 0.922 g/cm ³ ) (carbon concentration: 2.5 wt%) ^. A modified ^polyolefin layer consisting of
It was attached using die molding so that the layer thickness was 0.5 mm.

On this maleated polyethylene layer, the same epoxy resin as above was applied uniformly to a thickness of approximately 30 μm using an airless gun, and then a large press machine was used to apply a Teflon sheet for mold release on the surface of an 80 x 500 mm hot plate. After applying pressure for 3 minutes at a temperature of 160°C and a pressure of 0.1 Kg/cm ² , it was cooled and cut into 80 x 160 mm to produce a polyethylene sheet (polyolefin coated sheet) having a cured epoxy resin layer. .

Polyurethane prepolymer (Daiichi Kogyo Seiyaku Co., Ltd.) is placed on the epoxy resin cured layer of the above polyethylene sheet
Co., Ltd. (trade name: Mac Flex 350μ) to a thickness of about 30μm to form an uncured reaction-curing resin intermediate layer, and then immediately coated with the polyurethane prepolymer and the epoxy on the steel pipe pile. They were laminated so that the cured resin layers faced each other, and were temporarily fixed with a rubber belt.

In addition, approximately 2 mm is added to the butt part of the anti-corrosion coating sheet.
A gap was created, but the joint was filled using polysulfide elastic sealant.

The maximum temperature on the day of construction was approximately 30°C, and the uncured polyurethane hardened and began to develop adhesive strength in approximately 24 hours.

After 48 hours, the peel strength of the anticorrosive coating sheet was measured and was found to be approximately 7 kg/cm.

Steel pipe piles with anti-corrosion coating were left exposed to splash zone and tidal zone for two years.

Two years later, when observed, there was almost no change in the appearance, and when the peel strength was measured under the same conditions as above, it was about 6 kg/cm.

There was no occurrence of casting on the surface of the steel pipe pile that was peeled off to measure peel strength.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing an example of an embodiment in which an anticorrosive coating sheet is attached to the surface of a metal material. 11: Metal material, 12: Resin cured layer, 13: Epoxy resin cured layer, 14: Polyolefin coated sheet, 15: Reaction curable resin intermediate layer, 16: Unmodified polyolefin sheet, 17: Modified polyolefin layer.

Claims (1)

[Claims] 1. A hardened resin layer is attached to the surface of a metal material, and a polyolefin-coated sheet having a hardened epoxy resin layer is placed on the hardened resin layer so that the hardened epoxy resin layer faces the hardened resin layer. A method for anti-corrosion coating on the surface of a metal material, which comprises laminating layers with a reaction-curing resin intermediate layer interposed therebetween, and then completing curing of the reaction-curing resin intermediate layer and adhering a polyolefin coated sheet. 2. Claim 1, characterized in that the polyolefin coated sheet is composed of an unmodified polyolefin layer and a modified polyolefin layer, and the epoxy resin cured layer is laminated on the modified polyolefin layer. A method for anti-corrosion coating on the surface of metal materials. 3. The method for anti-corrosion coating of a metal material surface according to claim 1, wherein the polyolefin coated sheet is a molded product of modified polyolefin. 4. A method for anticorrosive coating of a metal material surface according to claim 2 or 3, wherein the modified polyolefin is a maleic acid-modified polyolefin. 5 The epoxy resin cured layer is bisphenol A
Claim 1 characterized in that it is formed of a cured product of and a heterocyclic modified polyamine.
A method for anti-corrosion coating on the surface of a metal material as described in . 6. The method for anti-corrosion coating of a metal material surface according to claim 1, wherein the reaction-curable resin intermediate layer is formed of a non-polyolefin resin. 7. The method for anti-corrosion coating of a metal surface according to claim 6, wherein the non-polyolefin resin is a resin having a polar group. 8. The method for anticorrosion coating of a metal surface according to claim 7, wherein the resin having a polar group is a resin containing nitrogen atoms and/or oxygen atoms as part of its constituent atoms. 9. The metal according to claim 8, wherein the resin containing nitrogen atoms and/or oxygen atoms as part of its constituent atoms is either a reaction-curing resin or a thermosetting resin. Method of anti-corrosion coating on surfaces.