JP2006233614A - Reinforcing member coated with high adhesion corrosion-proof coat, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reinforcing member coated with a high adhesion corrosion-proof coat enhanced in adhesion to concrete by forming firm protrusions in a state of being coated with epoxy resin, on a second layer corrosion-proof coat while solving a problem of pinholes inevitably formed in the corrosion-proof coat by forming two upper and lower layers of corrosion-proof coats on the surface of the reinforcing member by spraying an epoxy powder paint in a temperature condition where the performance of epoxy resin can be maintained. <P>SOLUTION: The reinforcing member coated with the high adhesion corrosion-proof coat having countless protrusions 3a on the surface of the second corrosion-proof coat 3 is manufactured by heating the reinforcing member 1, forming the first corrosion-proof coat 2 by spraying the epoxy powder paint 4 to the reinforcing member while the surface temperature of the reinforcing member is 200-250°C, and in this temperature condition, forming the second corrosion-proof coat 3 by spraying the epoxy powder paint 4 mixed with acrylic resin beads (b) with the grain size of 2.5-3 times as large as the grain size of epoxy resin powder (a), to the surface of the first corrosion-proof coat in a molten state. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a reinforcing bar material with an anticorrosion coating with improved adhesion performance to concrete.

Japan Society of Civil Engineers Concrete Library No.58 “Design Guidelines for Reinforced Concrete Using Epoxy Resin Painted Reinforcement (draft)” Page 19 Japanese Patent Publication No. 6-16868 JP 2001-90254 A

  In recent years, corrosion of reinforcing bars has progressed due to the influence of concrete aggregates and the like, and various accidents occur frequently, which has become a problem. Therefore, as can be seen in Patent Document 1 and the like, an epoxy-coated reinforcing bar in which an anticorrosion coating is formed by spraying an epoxy powder coating on the surface of the heated reinforcing bar material to be melted and adhered has been developed. The problem of rebar corrosion seems to have been solved, except for the pinhole problem that inevitably occurs.

  However, as can be seen in Non-Patent Document 1, it is known that when epoxy coating is applied to reinforcing bars, long-term adhesion to concrete is reduced to about 80% of the value of uncoated reinforcing bars and concrete. This has a significant effect on the strength of the concrete structure and is a serious problem with regard to its life.

  The invention described in Patent Document 2 has been proposed in order to solve such a problem, and an anticorrosion coating using a synthetic resin powder coating (specifically, a thermoplastic polyethylene isophthalate terephthalate copolymer). In the reinforcing bar material formed with the above, the surface of the anticorrosion coating is characterized by spraying inorganic particulates such as silica sand, ceramic powder such as alumina powder, glass powder, etc. to improve the adhesion performance to concrete.

  This conventional example will be described with reference to FIG. First, as shown in FIG. 4A, shot blasting is performed on the reinforcing bar 41 to remove rust and dirt on the surface of the reinforcing bar 41 and to roughen the surface of the reinforcing bar 41 to make it rough. Thereafter, as shown in FIG. 4B, the reinforcing bar 41 is heated, and as shown in FIG. 4C, the surface of the reinforcing bar 41 having a predetermined temperature (260 to 400 ° C.) is applied. Then, the synthetic resin powder coating 44 is sprayed to melt and adhere. Then, as shown in FIG. 4D, while the synthetic resin powder coating 44 is in a molten state, the inorganic particulate matter 40a is sprayed and subjected to a cooling process, as shown in FIG. In this way, a rebar material with a highly adhered anticorrosion coating in which the inorganic particulate matter 40a is fixed to the surface of the anticorrosion coating 42 is obtained.

  According to this conventional example, by spraying the inorganic particulate matter 40a while the synthetic resin powder coating 44 is in a molten state, a part of the inorganic particulate matter 40a is buried in the anticorrosion coating 42 and fixed to the anticorrosion coating 42, The other portions are exposed on the anticorrosion coating 42 to form innumerable protrusions (irregularities), and the adhesion performance to the concrete is improved in spite of the reinforcing bars with the anticorrosion coating.

  However, in this conventional example, since different materials are bonded to the surface of the anticorrosion coating 42, it is said that a part of the inorganic particulates 40a is bonded to the anticorrosion coating 42. No, there is a high possibility that the inorganic granular material 40a is peeled off due to contact with other objects, and it is assumed that the adhesion performance is significantly lowered due to the deterioration of the anticorrosion coating 42 over time.

  In addition, when a synthetic resin powder coating 44 such as an epoxy powder coating is sprayed on the heated reinforcing bar material 41 and melt-bonded to form the anticorrosion coating 42, generally several pinholes per 1 m of the reinforcing bar material are used. (Very small bubbles) are inevitably generated, so pinhole inspection is performed on the entire length of all products, and it is confirmed that the number of pinholes is less than the allowable value before shipping to the factory. However, in the above-mentioned conventional example, since one layer of the anticorrosion coating 42 is formed and the inorganic granular material 40a is sprayed on the surface thereof, the pinhole generated in the one layer of the anticorrosion coating 42 is a weak point in the anticorrosion performance as it is. Will remain as.

  As a solution to such a problem, the applicant of the present application forms a two-layer anticorrosion coating on the surface of the reinforcing bar material by spraying a powder coating, and the problem of pinholes inevitably generated in the anticorrosion coating At the same time, a method for producing a rebar with a highly adherent anticorrosion coating that can increase the adhesion with concrete by forming innumerable protrusions with the second anticorrosion coating has already been developed. Japanese Patent Application No. 2003-304077 As proposed.

  In this manufacturing method, a reinforcing bar material is heated, and while the surface temperature of the reinforcing bar material is 250 to 390 ° C., an epoxy powder coating is sprayed onto the reinforcing bar material to form a first anticorrosive coating. At the same time, zinc-rich powder coating (powder coating consisting of zinc metal powder, epoxy resin and curing agent) is sprayed onto the surface of the first anti-corrosion coating in the molten state. Forming a second anticorrosion coating, and then cooling the reinforcing bars with the first and second anticorrosion coatings to reinforce the reinforcing bars with a high adhesion anticorrosion coating having innumerable protrusions formed by the second anticorrosion coating It is characterized by manufacturing.

  According to this method, even if a pinhole is generated in the first anticorrosive film of the first layer, the pinhole of the first anticorrosive film is formed by forming the second anticorrosive film on the first anticorrosive film in a molten state. Will be repaired. Even if the pinhole remains unrepaired, the probability that the pinhole of the first anticorrosion coating and the pinhole of the second anticorrosion coating match is almost zero, so the anticorrosion caused by the pinhole of the first anticorrosion coating The weak point on performance is covered with the second anticorrosion coating, and the weak point on the anticorrosion performance due to the pinhole of the second anticorrosion coating is covered with the first anticorrosion coating. As a result, high anticorrosion performance can be secured.

  Nevertheless, the second anticorrosion film made of zinc rich powder paint is formed on the first anticorrosion film made of epoxy powder paint, and the adhesion to concrete is enhanced by the countless protrusions formed by the second anticorrosion film. As in the case of forming protrusions by adhering another granular material to the surface of the coating, there is no risk of the protrusions coming off due to contact with other objects, and high adhesion performance can be ensured over many years.

  However, it has been found that the previously proposed method has room for improvement in the following points. That is, first, since the performance of the epoxy resin deteriorates at high temperatures, it is desirable to spray the epoxy powder coating under the conditions as low as possible. However, in the above method, the second anticorrosive film is formed. Since the granular material mixed with the epoxy powder coating is zinc metal powder (inorganic granular material), this is applied to the surface of the second anticorrosive coating as a strong protrusion coated with a binder component (epoxy resin) In order to express it, it is necessary to perform the second spray coating under a high temperature condition of 250 to 390 ° C., and it is difficult to maintain the performance of the epoxy resin.

  Secondly, when conducting rust prevention performance experiments at high temperatures, zinc (zinc component) adversely affects the epoxy resin and degrades the epoxy resin component. Leads to.

Third, zinc exhibits degradation against chloride ions. In the above method, since the zinc metal powder becomes a protrusion coated with the epoxy resin as the binder component, it is protected by the coating layer, but when the coating layer cracks, it is caused by chloride ions. Deterioration may occur, and depending on applications such as harbor structures and marine structures, it will lead to future weaknesses.

  The present invention is an improvement of the above-described points, and the object of the present invention is that the surface of the reinforcing bar material is vertically moved by spraying an epoxy powder coating under a temperature condition capable of maintaining the performance of the epoxy resin. In order to solve the problem of pinholes inevitably generated in the anticorrosion film by forming a layer of anticorrosion film, and at the same time to develop a strong protrusion in a state where the second anticorrosion film is coated with epoxy resin, An object of the present invention is to provide a rebar material with a highly adherent anticorrosion coating that can increase the adhesion strength between the reinforcing bar and the surface.

  In order to achieve the above object, the technical measures taken by the present invention are as follows. That is, the rebar with a highly adherent anticorrosion coating according to the present invention forms a first anticorrosion coating with an epoxy powder coating on the surface of the rebar, and the particle size of the epoxy resin powder on the surface of the first anticorrosion coating. A second anticorrosion film was formed with an epoxy powder coating mixed with 2.5 to 3 times the diameter of acrylic resin beads, and the adhesion to concrete was enhanced by the countless protrusions formed by the second anticorrosion film. (Claim 1).

  According to the present invention, a method for manufacturing a reinforcing bar material with a high adhesion anticorrosive coating is a method of heating a reinforcing bar material and spraying an epoxy powder coating onto the reinforcing bar material while the surface temperature of the reinforcing bar material is 200 to 250 ° C. The first anticorrosion film is formed by applying an acrylic resin having a particle diameter of 2.5 to 3 times the particle diameter of the epoxy resin powder on the surface of the first anticorrosion film in a molten state. The second anticorrosion coating is formed by spraying and adhering an epoxy powder coating mixed with resin beads to form a second anticorrosion coating, and then cooling the reinforcing bars with the first and second anticorrosion coating. The present invention is characterized in that a reinforcing bar material with a high adhesion anticorrosion coating having innumerable protrusions formed by the above method is manufactured (claim 2).

  According to the reinforcing material with a high adhesion anticorrosive film of the present invention, even if pinholes are generated in the first anticorrosive film of the first layer, the second anticorrosive film is formed on the first anticorrosive film in a molten state. The pinhole of the first anticorrosion coating is repaired. Even if the pinhole remains unrepaired, the probability that the pinhole of the first anticorrosion coating and the pinhole of the second anticorrosion coating match is almost zero, so the anticorrosion caused by the pinhole of the first anticorrosion coating The weak point on performance is covered with the second anticorrosion coating, and the weak point on the anticorrosion performance due to the pinhole of the second anticorrosion coating is covered with the first anticorrosion coating. As a result, high anticorrosion performance can be secured.

  Nevertheless, the second anticorrosion coating by the epoxy powder coating in which acrylic resin beads having a particle size of 2.5 to 3 times the particle size of the epoxy resin powder are mixed on the first anticorrosion coating by the epoxy powder coating. Since the adhesion to concrete is increased by the innumerable protrusions formed by the second anticorrosion coating, it is different from other objects as in the case of forming protrusions by adhering another granular material to the surface of the anticorrosion coating. There is no risk of the protrusions coming off due to contact or the like, and high adhesion performance can be secured for many years.

According to the method for manufacturing a reinforcing bar with a highly adhered anticorrosive coating according to the present invention, the reinforcing bar with a highly adhered anticorrosive coating according to claim 1 can be manufactured. That is, the reinforcing bar material is heated, and while the surface temperature of the reinforcing bar material is 200 to 250 ° C., in other words, the epoxy powder paint is sprayed onto the reinforcing bar material under a low temperature condition that can maintain the performance of the epoxy resin. In addition to forming the first anticorrosive film by melting and adhering, the particle size of the epoxy resin powder is subsequently increased on the surface of the first anticorrosive film in the molten state under the same temperature condition. As the second anti-corrosion coating is formed by spraying an epoxy powder coating mixed with 2.5 to 3 times the acrylic resin beads to melt and adhere, the unmelted acrylic resin beads are locally lifted Thus, strong protrusions in a state of being coated with the binder component (epoxy resin) of the epoxy powder coating are developed. In addition, since the first anticorrosion coating and the second anticorrosion coating are adhered in a molten state, they exhibit the same properties as a single layer coating and do not peel between the first and second anticorrosion coatings.

  It should be noted that when the preheating temperature of the reinforcing bar material is 200 ° C. or lower, the epoxy resin is hardly melted, and it takes a long time to spray the epoxy powder coating, and when it is 250 ° C. or higher, it is difficult to maintain the performance of the epoxy resin. Further, when the particle diameter of the acrylic resin beads is 2.5 times or less than the particle diameter of the epoxy resin powder under a temperature condition of 200 to 250 ° C., protrusions due to unmelted beads on the surface of the second anticorrosion coating If the particle size of the acrylic resin beads is not less than 3 times the particle size of the epoxy resin powder, the protrusions due to the unmelted beads are too large and the coating with the epoxy resin becomes incomplete. In other words, in any case, it is not possible to form a strong protrusion that is difficult to peel off.

  Thus, by forming the second anticorrosion film on the first anticorrosion film, not only can the problem of pinholes inevitably generated in the anticorrosion film be solved, but also a relatively low temperature condition of 200 to 250 ° C. Underneath (temperature conditions that can maintain the performance of the epoxy resin), spray an epoxy powder coating mixed with acrylic resin beads whose particle size is 2.5 to 3 times the particle size of the epoxy resin powder, Since protrusions are developed in the second anticorrosion coating itself, there is no risk of the protrusions being peeled off, and a rebar material with a highly attached anticorrosion coating that can ensure high adhesion performance can be produced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereby. FIG. 1 is a schematic cross-sectional view of a main part showing an example of a reinforcing bar with a highly adherent anticorrosive coating according to the present invention, and FIG. 2 is a key for explaining the adhesion performance between a reinforcing bar with a highly adherent anticorrosive coating and concrete C. It is typical sectional drawing of a part. 1 and 2, reference numeral 1 denotes a reinforcing bar material (for example, deformed reinforcing bar), and its surface 1a is a rough surface roughened by shot blasting. 2 is a first anticorrosion coating formed by an epoxy powder coating (powder coating consisting of an epoxy resin, a curing agent, and a pigment as a base resin) formed on the surface 1a of the reinforcing bar 1; It is the 2nd anti-corrosion film formed in this. The second anticorrosion coating 3 is formed of an epoxy powder coating in which acrylic resin beads having a particle size of 2.5 to 3 times the particle size of the epoxy resin powder are mixed, and the second anticorrosion coating 3 itself. Innumerable protrusions 3a formed by the above-described structure are formed so that these protrusions 3a bite into the concrete C, thereby being firmly attached to the concrete C (stronger than in the case of unpainted reinforcing bars). The protrusion 3a is in a state where the unmelted acrylic resin beads are coated with an epoxy resin which is a binder component of the epoxy powder paint.

  Next, the manufacturing method of said rebar with a highly adherent anticorrosion coating will be described with reference to FIG. First, as shown in FIG. 3A, shot blasting is performed on the reinforcing bar material 1 to remove rust and dirt on the surface 1a of the reinforcing bar material 1, and the surface 1a of the reinforcing bar material 1 is roughened and roughened. .

  After that, as shown in FIG. 3B, the reinforcing bar 1 is heated to 200 to 250 ° C. by a known heating means.

  Next, as shown in FIG. 3C, an epoxy powder coating (epoxy resin powder a as a base resin, hardener not shown) and a surface 1a of the reinforcing bar 1 heated to 200 to 250 ° C. (Powder coating material made of pigment) 4 is sprayed and fused to form a first anticorrosive coating 2 having a thickness of 100 to 200 μm, as shown in FIG.

  An acrylic resin having a particle size of 2.5 to 3 times the particle size of the epoxy resin powder a on the surface of the first anticorrosive coating 2 in a molten state under the same temperature condition (200 to 250 ° C.) The second anticorrosion coating 3 having a thickness of 100 to 200 μm is formed by spraying and adhering the epoxy powder coating 4 mixed with the beads b, and then cooling the reinforcing bars with the first and second anticorrosion coating. Then, as shown in (E) of FIG. 3, a highly reinforcing anticorrosion coating-coated reinforcing bar having innumerable protrusions 3 a formed by the second anticorrosion coating 3 is manufactured.

  According to said manufacturing method, the reinforcing bar material 1 is heated to 200-250 degreeC which is the temperature range which does not reduce the performance of an epoxy resin, and the epoxy powder coating material 4 is sprayed on this temperature condition, and a 1st anticorrosion coating film 2 on the surface of the first anticorrosion coating 2 in a molten state under this temperature condition (200 to 250 ° C.), the particle size is 2.5 to 3 which is the particle size of the epoxy resin powder a. Since the second anticorrosive coating 3 is formed by spraying the epoxy powder coating 4 mixed with the double acrylic resin beads b, the unmelted acrylic resin beads b are locally lifted, and the binder of the epoxy powder coating 4 A strong protrusion 3a coated with the component (epoxy resin) is developed. In addition, since the first anticorrosion coating and the second anticorrosion coating are adhered in a molten state, they exhibit the same properties as a single layer coating and do not peel between the first and second anticorrosion coatings.

  Thus, the particle size is 2.5 to 3 times the particle size of the epoxy resin powder a on the first anticorrosive coating 2 in a molten state under a relatively low temperature condition of 200 to 250 ° C. Since the second anticorrosion coating 3 is formed by spraying the epoxy powder coating 4 in which the acrylic resin beads b are mixed, the second anticorrosion coating 3 itself has a strong protrusion 3a coated with an epoxy resin. Since there is no possibility that the protrusion 3a is peeled off, high adhesion performance can be ensured.

  Moreover, since the protrusion 3a coated with the epoxy resin is formed by the acrylic resin beads b, there is no adverse effect on the epoxy resin component as in the case where the protrusion is formed of zinc metal powder even under high temperature. Even if cracks occur in the coating layer of the protrusions 3a, there is no possibility of deterioration due to chloride ions as in the case of forming protrusions with zinc metal powder.

  Further, the second anticorrosion coating 3 is formed by spraying the epoxy powder coating 4 in which the acrylic resin beads b are mixed on the first anticorrosion coating 2 in the molten state. Even if a pinhole occurs in 2, by forming the second anticorrosion coating 3 thereon, the pinhole of the first anticorrosion coating 2 is restored, even if the pinhole remains unrepaired Since the probability that the pinhole of the first anticorrosion coating 2 matches the pinhole of the second anticorrosion coating 3 is almost zero, the weak point in the anticorrosion performance due to the pinhole of the first anticorrosion coating 2 is the second anticorrosion. The first anticorrosion coating 2 covers the weak point in the anticorrosion performance that is covered with the coating 3 and is caused by the pinhole of the second anticorrosion coating 3.

  Therefore, coupled with the absence of adverse effects on epoxy resin components and deterioration due to chloride ions as in the case of using zinc metal powder, high anticorrosion performance can be ensured.

1 is a schematic cross-sectional view of a reinforcing bar with a highly adherent anticorrosive coating according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is typical sectional drawing explaining the adhesion performance of the reinforcing material with a high adhesion anti-corrosion film which concerns on this invention, and concrete. It is explanatory drawing of the manufacturing method of the rebar with a high adhesion anti-corrosion film concerning the present invention. It is explanatory drawing of the manufacturing method of the conventional rebar material with a highly adhesion anti-corrosion coating.

Explanation of symbols

1 Rebar material
2 First anticorrosion coating
3 Second anticorrosion coating
3a protrusion
4 Epoxy powder paint
a Epoxy resin powder
b Acrylic resin beads

Claims (2)

  A first anticorrosion coating with an epoxy powder coating is formed on the surface of the reinforcing bar material, and acrylic resin beads having a particle size of 2.5 to 3 times the particle size of the epoxy resin powder on the surface of the first anticorrosion coating A reinforcing bar with a highly adhered anticorrosive coating, wherein a second anticorrosive coating is formed from an epoxy powder coating mixed with bismuth and the adhesion to concrete is enhanced by innumerable protrusions formed by the second anticorrosive coating.   While the reinforcing bar material is heated and the surface temperature of the reinforcing bar material is in the range of 200 to 250 ° C., the first anticorrosive coating is formed by spraying an epoxy powder paint on the reinforcing bar material and melt-adhering, and this temperature condition Below, melted by spraying an epoxy powder coating mixed with acrylic resin beads having a particle size of 2.5 to 3 times the particle size of the epoxy resin powder on the surface of the first anticorrosive coating in a molten state. A second anticorrosion coating is formed by adhering, and then the first and second anticorrosion coating rebars are cooled to thereby provide a highly adherent anticorrosion coating rebar having innumerable protrusions formed by the second anticorrosion coating. A method for producing a reinforcing bar material with an anticorrosion coating, characterized by producing a material.

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