JPH0519458B2 - - 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 anticorrosive coating layer at the location where the damage occurred.

[Prior art and its problems] A method for anticorrosion 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, and the polyolefin surface of this polyolefin-covered sheet is heated directly using the flame of a gas burner or hot air to form an adhesive layer that is in contact with the surface to be coated with anti-corrosion coating. This is carried out by methods such as softening the agent layer and heat-pressing it.

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-coated sheet to soften the heat-melting adhesive layer on the backside to a bondable state, so this heating may cause thermal deterioration of the surface of the polyolefin-coated sheet. There's a problem. Furthermore, if we try to apply the above method to, for example, a steel pipe pile driven on the coast or the coating of a steel ceiling plate, even if heated, the adhesive layer will not reach a softened state where it can be bonded due to being cooled by seawater. There is also the problem that effective attachment cannot be carried out in many cases.

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
It is necessary to heat the material to about 150℃, and therefore, even with these methods, it is not possible to apply an effective 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 reaction-curable resin layer attached to the surface of a metal material, and a polyolefin-covered sheet having an epoxy resin cured layer on the reaction-curable resin layer. Provided is a method for anticorrosive coating on the surface of a metal material, which is characterized in that after the curable resin layer is laminated so as to face the curable resin layer, the curing of the reaction curable resin layer is completed and a polyolefin coated sheet is adhered.

The adhesion between the cured epoxy resin layer provided on the polyolefin-covered sheet and the reaction-curable resin layer attached to the surface of the metal material can also be achieved by interposing an intermediate layer of reaction-curable resin therebetween.

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

Furthermore, since no particular heating is required when applying the anticorrosion coating, there is no thermal deterioration of the polyolefin coated sheet due to heating, and the anticorrosion property is good.

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

Basically, the present invention first attaches a reaction-curable resin layer 12 to the surface of a metal material 11 (surface to be coated with anti-corrosion), separately prepares a polyolefin coating sheet 14 having a cured epoxy resin layer 13, and then After laminating the polyolefin-covered sheet 14 under pressure so that the resin cured layer 13 faces the reaction-curable resin layer 12, the curing reaction of the reaction-curable resin 12 in an uncured state is completed, and the polyolefin-covered sheet 14 This is an anti-corrosion coating method that adheres 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, parts of steel pipe piles and sheet piles used for seawalls, etc. that come into contact with seawater are cooled by seawater, so conventional methods that include heating operations do not 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 has an epoxy resin cured 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 16 is laminated on the surface of an unmodified polyolefin sheet 15. In the latter case, a cured epoxy resin layer 13 is laminated on the modified polyolefin layer.

As the unmodified polyolefin sheet, those used as 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-
Olefin homopolymers such as 4-methyl-1-butene, ethylene/propylene copolymers, ethylene/1-butene copolymers, propylene/1-butene
Obtained by crosslinking olefin copolymers such as butene copolymers, ethylene/vinyl acetate copolymers, and ethylene/acrylic acid ester copolymers, and these olefin homopolymers or olefin copolymers by known methods. Examples include polymeric substances.

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 the modified polyolefin layer 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. Monomers contained in the molecule (e.g. vinyl glycidyl ether,
Acrylic glycidyl ether, vinyl glycidyl thioether, glycidyl acrylate, glycidyl methacrylate, p-glycidyl styrene)
Examples include polymers graft-modified with, etc. In particular, it is preferable to use polyethylene graft-modified using 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, it is preferable to use a heterocyclic modified polyamine. However, in consideration of the balance between adhesion to modified polyolefins and reaction-curable resins described later and the above-mentioned weather resistance, it is often preferable to use modified aliphatic polyamines. Therefore, modified aliphatic polyamines are generally used.

Examples of modified aliphatic 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 a modified polyolefin layer is 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 in the range of 1 to 4 mm. Sa is 0.05~
5 mm, preferably in the range of 0.1 to 3.5 mm.

When the polyolefin-coated 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 4 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 attachment of a cured epoxy resin layer 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 a 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 harden the epoxy resin while softening the modified polyolefin layer, or apply the epoxy resin to a laminated sheet heated to a temperature below the melting point using the method described above, and integrate the modified polyolefin layer and the epoxy resin while hardening the epoxy resin. to obtain a polyolefin-coated sheet having a cured epoxy resin layer.

The heating described above can be carried out according to conventional techniques. For example, it is possible to use an infrared heater or the like, but in order to more firmly adhere and integrate the laminated layers, it is preferable to heat them under pressure using, for example, 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.

Even when using a sheet made only of modified polyolefin, it can be produced according to the above method.

In addition, polyolefin (modified or unmodified)
Of course, the sheet may also contain additives that are normally contained (eg, antioxidants, pigments, and other additives).

The polyolefin coated sheet produced in this way is placed on the reaction-curable resin layer 12 formed on the surface of the metal material 11 to be coated with anti-corrosion, so that the epoxy resin cured layer 13 and the reaction-curable resin layer 12 are facing each other. Laminate and glue as shown. Bonding is usually done under pressure.

The reaction-curing resin layer can be applied in accordance with a conventional method of coating the metal material to be coated with corrosion protection using methods such as brush coating or spray coating. The thickness of the reaction-curable resin layer is generally 3 to 100 μm, preferably 10 to 50 μm.

As the resin forming the reaction-curable resin layer, a resin having adhesive properties with the epoxy resin cured layer is used. Further, as a matter of course, the resin has adhesive properties with metal materials.

Therefore, it is preferable to use an epoxy resin as the reaction-curable resin, and it is particularly preferable to use the same epoxy resin as that used in forming the above-mentioned epoxy resin cured layer. Also,
When a modified aliphatic polyamine curing agent is used as the organic polyamine curing agent, the adhesion to the cured epoxy resin layer of the polyolefin-coated sheet is often particularly good.

When using a bisphenol A-based main agent and an organic polyamine curing agent, the ratio of the amounts used can be determined in accordance with the prior art as described above.

Note that a polyurethane resin can also be used as the reaction-curable resin. However, in this case, it is not necessary to interpose a reaction-curing resin intermediate layer, which will be described later.

The above-mentioned reaction-curable resin layer must be uncured at the time of the lamination operation, or at least the curing reaction must not be completed. When the curing reaction of the reactive curable resin is completed, the reactive curable resin loses its adhesive ability at room temperature.

There is no particular restriction on the method of laminating the polyolefin coated sheet onto the reaction-curable resin layer, 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. I can do it. Although the present invention does not require heating, the surface of the polyolefin coated sheet can be heated to, for example, about 50 to 60°C in order to accelerate curing.

The polyolefin-covered sheet having the epoxy resin cured layer laminated in contact with the reaction-curable resin layer is thus integrated with strong adhesion upon completion of curing of the reaction-curable resin.

In this way, the present invention allows the polyolefin coated sheet to be attached without any particular heating.
Not only does it have good corrosion resistance, but it also has particularly good adhesion by interposing a reaction-curing resin intermediate layer between the epoxy resin cured layer and the reaction-curing resin layer of the above-mentioned polyolefin-coated sheet and laminating them under pressure. , corrosion resistance is further improved.

FIG. 2 is a diagram schematically showing an example in which a polyolefin coating sheet is attached via a reaction-curable resin intermediate layer.

In FIG. 2, the metal material is indicated by 21, and the reactive hardening resin layer is indicated by 22. Further, the epoxy resin cured layer is indicated by 23, and the polyolefin coated sheet is indicated by 24. The unmodified polyolefin sheet constituting the polyolefin coated sheet is designated by 25, and the modified polyolefin layer is designated by 26.

That is, in the configuration shown in FIG. 2, a reaction curable resin intermediate layer 27 is interposed between the reaction curable resin layer 22 and the epoxy resin cured layer 23.

Also in the method of interposing a reaction-curable resin intermediate layer, the polyolefin-covered sheet described above can be used. However, as the organic polyamine curing agent for the epoxy resin cured layer attached to the polyolefin coated sheet, it is particularly preferable to use a heterocyclic modified polyamine described below.

The resin forming the reaction-curable resin layer attached to the surface of the metal material can be substantially the same as the above-mentioned epoxy resin. However, since the reaction-curing resin intermediate layer is interposed between the reaction-curing resin layer and the cured epoxy resin layer, the adhesion of the reaction-curing resin layer to the resin forming the reaction-curing resin intermediate layer must be considered. For example, there is no need to particularly consider adhesion to the cured epoxy resin layer. Therefore, there is an advantage that a heterocyclic modified polyamine or an aromatic modified polyamine that produces an epoxy resin with excellent weather resistance can be used as the raw organic polyamine.

Examples of heterocyclic modified polyamines include: Examples of aromatic modified polyamines include can be mentioned.

As the resin forming the reaction-curable resin intermediate layer, a resin having substantial adhesion to both the epoxy resin cured layer and the reaction-curable resin layer is used.

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.

When using an epoxy resin as the material for the intermediate layer, 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.

A method for interposing the reaction-curable resin intermediate layer between the epoxy resin cured layer and the reaction-curable resin cured layer is to apply it onto the reaction-curable resin layer attached to the surface of the metal material before the curing reaction is completed. Although it is also possible to use a method, generally a method of coating on the cured epoxy resin layer on the covering sheet side is used.

Note that the reaction-curing resin intermediate layer coated on the polyolefin-covered sheet is usually laminated and adhered onto the reaction-curing resin layer in an uncured state. However, it does not always need to be uncured; the reaction-curing resin layer is in an uncured state, so even if the reaction-curing resin intermediate layer is cured, it will adhere firmly and have good weather resistance. shows. That is, instead of the reaction-curable resin intermediate layer described above, a cured resin intermediate layer such as a cured polyurethane resin may be used.

However, when using the coating method on the reaction-curing resin layer, the polyolefin is applied while the resin forming the reaction-curing resin intermediate layer has adhesive properties (for example, before the curing reaction is completed). Laminate and adhere the covering sheets.

The thickness of the reaction-curing resin intermediate layer is 3 to 200 μm,
Preferably it is in the range of 10 to 100 μm.

Next, examples of the present invention will be shown.

Example 1 2 mm thick low density polyethylene (MI: 0.1 g/
Maleated polyethylene (MI: 1.5 g/10 min, density: 0.922 g/cm ³ , maleation equivalent: 1×) on the surface of ^a sheet (carbon concentration: 2.5 wt%) of Modified polyolefin layer consisting of 10 ^-5 mol/g PE) is formed by T-die molding to increase the layer thickness.
It was attached so that it was 0.5mm.

On this maleated polyethylene layer, an epoxy resin consisting of bisphenol A type (epoxy equivalent, 190) and aliphatic modified polyamine (Epocure 3012, manufactured by Yuka Ciel Epoxy Co., Ltd.) was applied to a thickness of approximately 30 μm using an airless gun. After applying it evenly,
Using a large press machine with a Teflon sheet for mold release pasted on the surface of a hot plate measuring 80 x 500 cm, the temperature was 160°C and the pressure was 0.1.
After pressurizing for 3 minutes under the condition of Kg/cm ² , it was cooled and cut into a size of 80×160 cm to produce a polyethylene sheet (polyolefin coated sheet) having an epoxy resin cured layer.

Steel pipe piles (diameter
After sandblasting the surface of the area corresponding to the tidal splash zone (508 mm, wall thickness 9 mm), apply the same epoxy resin as above to a thickness of about 40 μm, and immediately apply the above The anticorrosive coating sheets were laminated so that the cured epoxy resin layer and the uncured epoxy resin layer 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 epoxy resin, which is a reactive hardening resin, 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 when the peel strength reached approximately 15 kg/cm, interfacial peeling occurred between the cured epoxy resin layer and the maleated polyethylene layer.

Steel pipe piles with anti-corrosion coating were left exposed to spray zones and tidal bodies 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 approximately 14 kg/cm.

No rust was observed on the surface of the steel pipe pile that was peeled off to measure peel strength.

Example 2 In Example 1, a heterocyclic modified amine (manufactured by Yuka Ciel Epoxy Co., Ltd., Epomate B-001, amine value :280), and then polyurethane prepolymer (manufactured by Dai-ichi Kogyo Yakuhin Co., Ltd., trade name: Mac) on the epoxy resin cured layer of the polyethylene sheet.
Flex 350u) was applied to a thickness of approximately 30 μm, and the anticorrosion coating of the steel pipe pile was applied in the same manner, except that this polyurethane prepolymer and the uncured epoxy resin layer (reactive hardening resin layer) were placed facing each other. I did it.

The maximum temperature on the day of construction was approximately 30℃, and approximately
In 24 hours, the epoxy resin, which is a reaction-curable resin, hardened and began to develop adhesive strength.

After 48 hours, the peel strength of one sheet of anticorrosion coating material was measured, and the peel strength was approximately 7 kg/cm.

The steel pipe pile provided with the anti-corrosion coating was left for two years under the same conditions as in Example 1.

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.

No rust was observed 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. Second
The figure is a diagram schematically showing another embodiment in which an anticorrosive coating sheet is attached to the surface of a metal material. 11: Metal material, 12: Reaction curable resin layer, 1
3: Epoxy resin cured layer, 14: Polyolefin coated sheet, 15: Unmodified polyolefin sheet, 16: Modified polyolefin layer, 21: Metal material, 22: Reaction curable resin layer, 23: Epoxy resin cured layer, 24: Polyolefin coating sheet, 2
5: unmodified polyolefin sheet, 26: modified polyolefin layer, 27: reaction-curable resin intermediate layer.

Claims (1)

[Scope of Claims] 1. A reaction-curable resin layer is attached to the surface of a metal material, and a polyolefin-covered sheet having an epoxy resin cured layer is placed on the reaction-curable resin layer, and the epoxy resin cured layer is reaction-curable. 1. A method for anticorrosive coating of metal material surfaces, which comprises laminating the resin layer so as to face it, and then completing the curing of the reaction-curing resin layer and adhering a polyolefin coating sheet. 2. A patent claim characterized in that the epoxy resin cured layer provided on the polyolefin coated sheet and the reaction curable resin layer attached to the surface of the metal material are bonded by interposing a reaction curable resin intermediate layer therebetween. A method for anti-corrosion coating on the surface of a metal material according to item 1. 3. Claim 1 or 3, wherein the polyolefin-covered 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. 2. The anticorrosion coating method for the surface of a metal material according to item 2. 4. A method for anticorrosive coating of a surface of a metal material according to claim 1 or 2, wherein the polyolefin coated sheet is a molded product of modified polyolefin. 5. The method for anticorrosive coating of a metal material surface according to claim 3 or 4, wherein the modified polyolefin is a maleic acid-modified polyolefin. 6 The epoxy resin cured layer is bisphenol A
3. A method for anticorrosive coating on a surface of a metal material according to claim 1 or 2, characterized in that it is formed from a cured product of and a modified aliphatic polyamine. 7. The anticorrosive coating method for a metal material surface according to claim 1 or 2, wherein the resin forming the reaction-curable resin layer is a two-component curable epoxy resin.