TWI398497B - Nano polyaniline anti-corrosive coating material - Google Patents

Description

Nano polyaniline anti-corrosive coating material

The present invention relates to an anti-corrosive coating material, and in particular, the present invention relates to a non-toxic nanopolyaniline anti-corrosive coating material for simultaneously coating a good coating area and coating The layer defect region provides a corrosion inhibiting function, and reacts the inhibitory anion with the metal cation to form a passivated mixed salt, thereby blocking the redox reaction, thereby achieving the function of suppressing the corrosion reaction.

In recent years, with the rapid development of industry and commerce, although it has brought many material enjoyment and convenience to life, it has brought many new social problems, including hazardous substances and waste electronic products. Since these discarded electronic products and substances are likely to cause serious harm to the human body and the environment, countries around the world have also established new regulations based on environmental protection reasons to impose stricter regulations on hazardous substances and discarded electronic products.

In the case of the European Union, the European Union has launched the Restriction of Hazardous Substances (RoHS) and Waste Electric and Electronic Equipment (WEEE) on July 1, 2006. The main restrictions are Covers ten categories of products such as information and home appliances, including six chemicals including lead, cadmium, mercury, hexavalent chromium, poly-brominated biphenyls (PBB) and poly-brominated diphenyl Ethers (PBDE). , the highest content should not exceed 1000ppm. Similar bans have been issued in other major countries or regions of the world.

Therefore, how to cooperate with the bans proposed by other countries to make electronic products using other alternative materials that do not harm the environment and the human body has become the focus of research and development in countries around the world. In particular, most of the coating materials commonly used in general construction or transportation vehicles contain banned toxic components, and it is urgent to switch to other environmentally friendly alternative materials to comply with the current national laws and regulations.

For example, conventional chromate primers will release inhibitory hexavalent chromium ions and form chromium oxide (Cr ₂ O ₃ ) in a corrosive environment. Because hexavalent chromium ions are not only highly toxic and may cause cancer, they are quite powerful against humans and the environment. In addition, the primer for traditional construction steel is usually made of lead lacquer (the main component is Pb ₃ O ₄ ). Because lead lacquer can react with fatty acids in oil medium to form insoluble organic lead salt, it is quite strong for steel. It is widely used as a primer for construction steel. However, lead lacquer also has a relatively high toxicity and does not meet the requirements of the Hazardous Substance Restriction Directive and the Guideline for Waste Electronic Products. Other materials that are both corrosion-resistant and environmentally friendly.

Therefore, one aspect of the present invention is to provide a nano polyaniline anti-corrosive coating material which is not toxic and polluting because of the toxicity and contamination of the nano polyaniline resist coating material, and can be formed by reacting an inhibitory anion with a metal cation. The passivation of the mixed salt successfully blocks the occurrence of the redox reaction, thereby achieving the function of suppressing the corrosion reaction, so that the problems encountered in the prior art can be effectively solved.

According to a specific embodiment, the nanopolyaniline anti-corrosive coating material of the present invention comprises a nano-polyaniline coating, a polymer coating and a polyurethane coating. Wherein, the polymer coating layer is formed on the surface of the nanopolyaniline coating by a polymerization reaction, and the polyurethane coating layer is formed on the polymer coating layer for stabilizing the naphthalene coating. Rice polyaniline anti-corrosive coating material. In this embodiment, the nano polyaniline anti-corrosive coating material can provide corrosion inhibition function in both the intact coating region and the coating defect region, and form a passivation barrier salt through the inhibitory anion and the metal cation, thereby blocking oxidation. The reduction reaction is carried out to achieve the function of suppressing the corrosion reaction.

In practical applications, the nanopolyaniline coating may comprise a mineral acid doped functionalized polyaniline, such as a functionalized polyaniline doped with camphorsulfonic acid and phenylphosphonic acid, and the nanopolyaniline resist coating material The content of polyaniline in the weight percentage is about 1% to 10%, but not limited thereto. In addition, the polyaniline in the nanopolyaniline anti-corrosive coating material can be uniformly dispersed in a room temperature-hardenable epoxy resin, a polyurethane, and an epoxy resin and an isocyanate-reacting adduct. In the agent. Wherein, the epoxy resin may be a solvent-based epoxy resin or an aqueous epoxy resin.

Compared with the prior art, the nano polyaniline anti-corrosive coating material according to the present invention is composed of a conductive high-molecular polyaniline and an anionic dopant, which can provide corrosion in both the intact coating region and the coating defect region. Suppress function. The main principle is to use the special redox functional composition of nano polyaniline organic metal to modify the thermosetting polymer resin to strengthen the moisture, oxygen, salt and acid-base chemical composition of the coating material for the external environment. It resists resistance, so as to effectively protect the substrate underneath.

Therefore, the nano polyaniline anti-corrosive coating material proposed by the invention can effectively solve the problem that the conventionally used chromate primer releases highly toxic and possibly carcinogenic hexavalent chromium ions, and the highly toxic lead-based primer. It is forbidden to continue to use the problem, so it can meet the above-mentioned specifications of the Hazardous Substance Restriction Directive and the Waste Electronic Product Directive. In addition, since the nanopolyaniline anti-corrosive coating material of the present invention can effectively improve the corrosion resistance of the steel material and the service life of the product, the nano-polymer of the present invention is more than the conventionally used anti-corrosion coating. The aniline anti-corrosive coating material has the advantages of low pollution, low addition amount, multiple protection and long anti-corrosion period.

In summary, the nano polyaniline anti-corrosive coating material proposed by the invention is suitable for various steels of high-tech industries, public buildings, steel structures, residential buildings, and transportation vehicles such as automobiles, airplanes, bridges, ships, and the like. And the construction materials, and can be widely used in polymer resin and coating materials and other related industries, in order to drive these related industries to establish non-toxic anti-corrosion coating materials related manufacturing technology, and strengthen the competitiveness of these related industries. And lay the foundation for the sustainable operation of the industry, so the nano polyaniline anti-corrosive coating material proposed by the invention does have considerable market potential.

The advantages and spirit of the present invention will be further understood from the following detailed description of the invention.

The invention provides an anti-corrosive coating material. As the name suggests, the nano polyaniline anti-corrosive coating material is combined with a conductive polymer polyaniline and an anionic dopant. And use epoxy resin used for hardening and esterification at room temperature as a binder, thereby generating a symbiotic addition environment blocking and corrosion resistance of one plus one and two, and having low pollution, low addition amount, multiple protection And the anti-corrosion effective period is long. First, the common corrosion phenomena and the multiple corrosion resistance mechanisms of the polyaniline used in the present invention will be described in detail first.

In general, corrosion is quite common in our daily lives, such as nails or rusty windows. As far as the chemical reaction principle is concerned, the corrosion phenomenon is an electrochemical redox reaction. In a typical steel material corrosion reaction, the anode reaction is that the iron atom (Fe) loses electrons and oxidizes to iron ions (Fe ²⁺ ), as for the cathode. The reaction is a reaction between oxygen and neutral or alkaline water to obtain electrons. The multiple anti-corrosion mechanisms possessed by the polyaniline used in the present invention include the following:

(1) Anode corrosion protection (precious metallization): The corrosion potential of the metal will migrate toward the noble metal by about 800 mV, that is, the metallization will be passivated and become less active.

(2) Producing a corrosion-resistant insoluble iron anion salt.

(3) The anion has corrosion resistance.

(4) A passivated metal oxide layer (α-Fe ₂ O ₃ ) is formed to suppress the cathodic redox reaction. Its chemical reaction formula is as follows:

In one embodiment, the nanopolyaniline anti-corrosive coating material can provide corrosion inhibition function in both the intact coating region and the coating defect region, and form a passivation-miscible salt through the inhibitory anion and the metal cation, thereby blocking oxidation. The reduction reaction achieves the function of suppressing the corrosion reaction.

Next, please refer to FIG. 1. FIG. 1 is a schematic cross-sectional view showing a nano-polyaniline anti-corrosive coating composite according to the present invention. As shown in FIG. 1, in the specific embodiment, the nano polyaniline anti-corrosive coating composite 1 of the present invention comprises a nano polyaniline coating 10, a polymer coating 12 and a polyurethane coating. 14. Wherein, the polymer coating layer 12 is formed on the surface of the nanopolyaniline coating 10 by a polymerization reaction, and the polyurethane coating layer 14 is formed on the polymer coating layer 12 for stabilizing the entire nano layer. Rice polyaniline anti-corrosive coating composite 1.

In practical applications, the nanopolyaniline coating 10 may comprise a mineral acid doped functionalized polyaniline, such as a functionalized polyaniline doped with camphorsulfonic acid and phenylphosphonic acid, and polymerized in the nanopolyaniline coating 10. The content of aniline is about 1% to 10% by weight, but not limited thereto.

Further, the polyaniline in the nanopolyaniline coating 10 can be uniformly dispersed in a binder composed of a room temperature-hardenable epoxy resin, a polyurethane, and an epoxy resin-isocyanate-reacted adduct. In fact, the epoxy resin may be a solvent-based epoxy resin or a water-based epoxy resin, but is not limited thereto.

Please refer to FIG. 2 , which is a flow chart showing the preparation and corrosion resistance mechanism of the nano polyaniline anti-corrosive coating material. As shown in FIG. 2, in step S10, a corrosion resistant component such as a conductive polymer polyaniline or an anionic dopant is combined, and a room temperature hardening modified esterified epoxy resin is used as a binder to form a nanopolyaniline coating. Layer material. When (1) the metal substrate corrodes in the environment; or (2) the coating forms an isopotential coupling with the metal defect, the nanopolyaniline coating material will undergo a redox reaction with the metal to form an iron oxide passivation film ( In step S12), at the same time, the living anion is also released to the corrosion reaction zone and participates in the corrosion reaction. At this time, the inhibitory anion also forms a passivation complex salt with the metal cation as a second protective layer for blocking the redox reaction (step S14), thereby slowing down the progress of the corrosion reaction.

In order to test the corrosion resistance of the nanopolyaniline anti-base coating of the present invention, various anti-corrosion tests can be carried out on the nano polyaniline anti-base coating. The results obtained by the experiment are as follows:

1. The present invention performs a solvent resistance test of a nanometer polyaniline anti-slip primer layer according to MIL-PRF-23377H, and rubs back and forth with a MEK wet cotton cloth for 25 times on a nanometer polyaniline resist primer layer. It is: the nano polyaniline anti-slip primer still maintains the original luster, and there is no falling paint or film peeling.

2. The present invention is based on MIL-PRF-23377H for the environmental test of a low-pollution polyaniline anti-corrosion coating system composed of a nano polyaniline anti-base coating and an epoxy primer and a polyurethane topcoat. contain:

(a) According to MIL-PRF-23377H, the water-immersion test of the scored test piece is performed for 96 hours, and the water temperature is 49±3 °C. The experimental result is: the paint film of the low-pollution polyaniline anti-corrosion coating system is still Keep it intact, and the phenomenon of nicks and no diffusion occurs.

(b) Performing a scotch and non-scratch test piece salt spray test according to MIL-PRF-23377H for up to 2000 hours, the temperature is 35±1.3 °C, and the implementation environment is 5% saline and PH 6.5~ Under the neutral environment of 7.2. The experimental results show that: polyaniline has a very good corrosion inhibition ability for bare metal. When the salt spray scoring test piece passes the above 2000 hours test, the salt spray scoring test piece has no blistering phenomenon and the nick is not diffused. When the salt spray unscratched test piece passed the above 2000 hours test, the salt spray unscratched test piece showed no blistering phenomenon and no rust phenomenon occurred.

Compared with the prior art, the nano polyaniline anti-corrosive coating material according to the present invention is composed of a conductive high-molecular polyaniline and an anionic dopant, and provides corrosion inhibition in the intact coating region and the coating defect region. Features. The main principle is to use the special redox functional composition of nano polyaniline organic metal to modify the thermosetting polymer resin to strengthen the moisture, oxygen, salt and acid-base chemical composition of the coating material for the external environment. It resists resistance, so as to effectively protect the substrate underneath.

Therefore, the nano polyaniline anti-corrosive coating material of the present invention can effectively solve the problem that the conventionally used chromate primer releases highly toxic and possibly carcinogenic hexavalent chromium ions, and the highly toxic lead-based primer is prohibited. Continue to use the problem, so it can meet the above-mentioned Hazardous Substance Restriction Directive and the relevant specifications of the Waste Electronic Product Directive. In addition, since the nanopolyaniline anti-corrosive coating material of the present invention can effectively improve the corrosion resistance of the steel material and the service life of the product, the nano-polymer of the present invention is more than the conventionally used anti-corrosion coating. The aniline anti-corrosive coating material has the advantages of low pollution, low addition amount, multiple protection and long effective period.

In summary, the nano polyaniline anti-corrosive coating material proposed by the present invention is suitable for various steels and structures of high-tech industries, public buildings, steel structures, residential buildings, and transportation vehicles such as automobiles, bridges, and ships. In terms of materials, it can be widely used in related industries such as polymer resins and coating materials, in order to drive related industries to establish relevant manufacturing technologies for non-toxic and anti-corrosive coating materials, strengthen the competitiveness of domestic and foreign sales, and lay a solid foundation for industrial sustainable operation. Basically, the nanopolyaniline anti-corrosive coating material proposed by the present invention does have considerable market potential.

The features and spirit of the present invention will be more apparent from the detailed description of the preferred embodiments. On the contrary, the intention is to cover various modifications and equivalents within the scope of the invention as claimed.

S10~S14. . . Process step

1. . . Nano polyaniline anti-corrosive coating composite

10. . . Nano polyaniline coating

12. . . Polymer coating

14. . . Polyurethane coating

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic cross-sectional view showing a nanopolyaniline anticorrosive coating composite according to the present invention.

Figure 2 is a flow chart showing the preparation and corrosion resistance mechanism of the nanopolyaniline anti-corrosive coating material.

S10~S14. . . Process step

Claims (4)

A nano polyaniline anti-corrosive coating material consisting of three layers of coating material, comprising: a nanometer polyaniline coating, which is doped with a polyaniline and an anion uniformly dispersed in a binder a polymer coating formed on a surface of one of the nanopolyaniline coatings by a polymerization reaction; and a polyurethane coating, the polyurethane An ester coating is formed on the polymer coating to stabilize the nanopolyaniline resist coating material; wherein the polyaniline is a functionalized polyaniline co-doped with camphorsulfonic acid and monophenylphosphoric acid. The nano polyaniline anticorrosive coating according to claim 1, wherein the polyaniline has a weight percentage of 1% to 10%. The nano polyaniline anticorrosive coating according to claim 1, wherein the binder may be any one of the following: a room temperature hardening epoxy resin, a polyurethane, and an epoxy resin. A binder composed of a reaction product of a resin and an isocyanate. The nano polyaniline anticorrosive coating material according to claim 3, wherein the epoxy resin is a solvent epoxy resin or an aqueous epoxy resin.