JPH0668092B2 - Anticorrosion coating composition for zinc plated steel member and zinc plated steel member coated with the composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a fatal damage caused by poor corrosion resistance of steel members, particularly automobile parts, which require high corrosion resistance,
For example, a coating composition for preventing oil leakage and fuel leakage due to perforation and peeling due to corrosion of the steel member,
By coating a steel member with zinc plating, the coating film does not cause defects such as cracks, peeling, blistering, shrinkage, etc.
In addition, the present invention relates to a paint capable of enhancing the rust preventive power of a steel material portion by a synergistic effect with zinc plating and preventing rusting, puncturing, and peeling of the steel material over a long period of time, and a zinc plated steel member coated with the paint. .

[Conventional technology]

Conventionally, most of the measures against corrosion of steel parts such as automobile parts are performed only with zinc plating or other metal plating, or by coating with anticorrosive paint such as polyester resin type, epoxy resin type, melamine alkyd resin type. If some high-level rust prevention is required, in addition to zinc-plating steel members,
General paints such as polyester resin-based paints and epoxy resin-based paints have been applied in anticipation of a synergistic effect with zinc plating.

[Problems to be Solved by the Invention]

However, when a high degree of rust prevention is required, general paint coatings on zinc plating, such as polyester resin coatings, epoxy resin coatings, and other conventional coating materials, have high water permeability. However, because of the small adhesion to the zinc plating surface, the coating film on the zinc plating is cracked, peeled, blistered, shrunk, etc. is there.

[Means for Solving the Problems]

The present inventors, in view of the above situation, as a result of diligent examination of the coating material to be coated on the zinc plating, by coating the coating material using a binder resin of a specific composition on the zinc plating, cracks in the coating film, It does not cause peeling, shrinkage, blistering, etc., and also has the effect of suppressing water permeation by the coating film. Furthermore, the sacrificial anticorrosion effect of zinc plating acts synergistically, and the rust preventive power in the steel part has never been seen before. The inventors have found that a highly excellent zinc plated steel member can be produced, solved the problems described above, and completed the present invention.

That is, the present invention provides a rust preventive coating composition for a zinc plated steel member containing A) an epoxy resin, B) a halogenated hydrocarbon elastomer described below, and C) a hydrocarbon elastomer described below, and the above composition. It is to provide a zinc-plated steel member attached with.

As the epoxy resin of A) used in the present invention, bisphenol A, bisphenol F or a divalent phenol derivative in which halogen or other nuclear substituent is introduced, as well as an initial condensation product of phenol, etc. are reacted with epichlorohydrin. There are those known in the prior art, such as the polymer obtained by the above process.

The epoxy resin is used in an amount of 5 to 70 parts by weight, preferably 10 to 40 parts by weight, based on 100 parts by weight of the total resin solid content of the paint. If it is less than 5 parts by weight, it is difficult to obtain the desired rust preventive power,
When it exceeds 70 parts by weight, it is difficult to find the combined effect with other resins.

Examples of the halogenated hydrocarbon elastomer of B) used in the present invention include natural elastomers, isoprene polymers, styrene-butadiene copolymers, butadiene polymers, chloroprene polymers, ethylene-propylene copolymers and acrylonitrile. -Acrylonitrile copolymer such as butadiene, butene polymer, chlorinated elastomers such as EPDM, the chlorine content is 60 wt% or more, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene and / or Polyolefin such as a copolymer of propylene and other monomers is chlorinated to have a chlorine content of 60% by weight or more.

The halogenated hydrocarbon elastomer is 5 to 70 parts by weight, preferably 10 to 4 parts by weight based on 100 parts by weight of the total resin solid content of the paint.
Used at a ratio of 0 parts by weight. If it is less than 5 parts by weight, it is difficult to obtain the desired rust preventive power, and if it exceeds 70 parts by weight, it is difficult to find a combined effect with other resins.

Further, the hydrocarbon elastomer of C) used in the present invention includes an acrylonitrile-butadiene copolymer and / or an acrylonitrile-butadiene copolymer partially having a hydroxy functional group or a carboxy functional group.

The hydrocarbon elastomer resin is the total resin solid content of the paint.
It is used in a proportion of 5 to 70 parts by weight, preferably 10 to 40 parts by weight in 100 parts by weight. If it is less than 5 parts by weight, it is difficult to obtain the desired rust preventive power, and if it exceeds 70 parts by weight, it is difficult to find a combined effect with other resins.

Each of the three kinds of resins A), B) and C) of the present invention has a unique function, and they act in a well-balanced manner with each other to generate a strong adhesive force on the zinc plating surface. At the same time, it is considered that it forms a tough film and exhibits a high degree of rust prevention.

That is, in the epoxy resin of A), the -OH group in the resin or the -OH group generated by the ring-opening reaction of the glycidyl group due to heating or the like is a very thin oxide film on the base metal itself and the metal surface, It is considered to improve the adhesive force by hydrogen bonding with adsorbed water and the like, and among them, the one synthesized from bisphenol A and epichlorohydrin is considered to be likely to exert its effect in terms of molecular arrangement.

The halogenated hydrocarbon elastomer of B) has a large halogen atom size, and the hydrocarbon elastomer of C) has a high molecular weight and large entanglement of molecules. Therefore, both elastomers of B) and C) have a high barrier. In addition, both elastomers have a cross-linking reaction upon heating, which enhances the barrier property to a higher degree.
By highly suppressing the permeation of moisture and the permeation of oxygen in the air, the elution of iron and zinc ions from the base metal and the oxidation reaction are suppressed, and the erosion of the base metal is delayed, but especially for the zinc plated surface. In this case, it is considered that the dissolution of zinc ions and the oxidation reaction are suppressed, and the progress of the sacrificial anticorrosive action of zinc is delayed, resulting in a significant improvement in rust preventive performance.

The halogenated elastomer of B) has a chlorination degree of 60% by weight.
The above chlorinated hydrocarbon elastomers are widely used, and their polarities and molecular sizes are well balanced,
It is considered that the barrier effect is likely to be exhibited, and is preferably used.

Furthermore, it is also considered that the chlorinated hydrocarbon elastomer causes a slight dechlorination or dehydrochlorination reaction by heating, which etches the base metal to enhance the metal activity and improve the adhesive force. .

On the other hand, C) acrylonitrile-butadiene copolymer which is a hydrocarbon elastomer and / or acrylonitrile partially having a hydroxy functional group or a carboxy functional group-
The butadiene copolymer is considered to have a barrier effect, and it is considered that the nitrile group improves the adhesive force by chelating with the base metal, and is preferably used.

Other resins and plasticizers may be mixed with the resin-based coating material of the present invention for the purpose of increasing the amount, improving workability, and improving the physical properties of the coating film. At that time, various compatibility is examined and a material that does not deteriorate the performance is selected, but the resins, plasticizers and the like described below are preferably used.

As the alkyd resin, it is possible to use a normal resin produced from a dibasic acid such as phthalic acid or isophthalic acid and a polyhydric alkole such as glycerin, neopentyl glycol, trimethylolpropane or pentaerythritol, but the oil length is short. Is preferable.

The mono- and / or poly-hydroxy aromatic resin is a phenol, a bisphenol A, a bisphenol F, or a phenol derivative such as a halogen derivative of these phenols or a phenol derivative in which another nuclear substituent is introduced. , A resin obtained by reacting formaldehyde, paraformaldehyde and the like, and either a resol type or a novolak type, which is formed by the difference in reaction phase form, can be used.

As a plasticizer for adjusting the hardness and flexibility of the finished coating film, adipic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, alkyl esters of dibasic acids such as phthalic acid, and various derivatives of toluenesulfonamide Besides, alkyl or phenyl orthophosphoric acid ester, acidic phosphoric acid ester, phosphorous acid ester and the like can be used.

In carrying out the method of the present invention, the above A) to C) are used.
Each of the resins described above, other resins, and a plasticizer are used as a solution containing a solvent to form a paint according to a conventional method. Pigments such as rust preventive pigments, coloring pigments, extender pigments: rust preventives, defoamers, pigment dispersants, anti-settling agents, leveling agents, color separation preventing agents, slipping agents, etc. Additives: and ketones, esters, alcohols, ethers, glycol ethers, glycol ether esters, nitrogen-containing solvents,
It is used as a coating containing a solvent such as an aliphatic type, an aromatic type, or a halogenated hydrocarbon as required. These solvents are added in order to dissolve the various resins of the present invention, and are added in an appropriate amount so as to have an optimum viscosity as a paint, but usually a solid content of 10 wt% to 50 wt% To be added.

The rust preventive pigment used in the present invention may be any as long as it is usually used in paints, for example, iron oxide, lead oxide,
There are various metal oxides such as zinc oxide, compounds of various metal acids such as phosphoric acid, chromic acid, silicic acid, lead acid and molybdic acid, and various metals such as zinc, lead and calcium, and mixtures thereof. These are added as needed. The mixing amount of the pigments including the anticorrosive pigment is in the range of 10 to 200 PHR (10 to 200 parts by weight with respect to 100 parts by weight of the resin solid content: the same hereinafter), and preferably 20 to 100 PHR. Used in the range.

The rust preventive agent and other additives are added if necessary, and depending on the effect of addition, about 0.01 to 10% by weight is added to the above paint before use.

For the steel member of the present invention, a raw material metal composed of iron, steel, cast iron, cast steel, stainless steel and the like and alloys thereof can be used.

These steel members are used after being plated with zinc. These zinc platings include fused zinc plating and electrozinc plating, but electrozinc plating is preferably used. These electric zinc platings can also be used as multi-layer platings of copper and zinc, nickel and zinc, or copper, nickel and zinc, and those that have been treated with chromate after zinc plating are used. You can also In particular, a chromate treatment is preferably carried out as a post-treatment in order to protect the zinc surface until coating after zinc plating. Preferable examples of such a steel member having zinc plating include fuel inlet pipes, fuel tanks, various oil pipes, various fuel pipes, etc. in automobile parts.

In applying the paint of the present invention to the zinc plated steel member of the present invention, the member is optionally surface-treated by various methods immediately before coating. Usually, solvent wiping treatment, solvent dipping treatment, to remove oil and grease that adhere to the surface,
Perform solvent vapor treatment.

In applying the coating composition of the present invention, if necessary, it is diluted with the same various solvents as those used in forming the coating material or a mixed solvent thereof. The amount of the solvent to be diluted is variously used depending on the method of application, but by adjusting the amount used, for example, usually 10 to 10 to obtain an optimum viscosity for the application method. Adjust so that it is within the range of 1000cps (25 ℃).

The coating composition of the present invention can be applied by a method used for coating general coating materials such as brush coating, dip coating, shower coating, air spray coating, airless spray coating and various electrostatic coating. .

After applying the coating composition of the present invention by any of the above-mentioned methods, it is dried at room temperature for a while and then dried by heating at a temperature of 100 to 180 ° C. for 5 to 30 minutes to form a coating film.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples, but these do not limit the present invention in any way. still,
Unless otherwise specified,% in this example represents% by weight.

Examples 1 to 6 After dissolving a resin solid content composition shown in Table 1 below in a solvent, an extender pigment 30PHR was added, and further, an anti-sagging agent, a surface preparation agent, and an additive for a pigment wetting agent were added to the paint, respectively. To 1.0,0.1,0.
After adding it to 1%, it was made into a paint by a conventional method.
After adjusting the coating viscosity of this paint with a solvent,
A 0.8 mm chromate-treated zinc plated steel pipe was dipped, baked and dried at 140 ° C. for 20 minutes.

However, the contents of the resin shown in Table 1 are as follows.

Epoxy resin A: Epicoat # 1001 (Ciel Chemical Co., Ltd.) Epoxy resin B: Epicoat # 1004 (Ciel Chemical Co., Ltd.) Chlorinated hydrocarbon resin A: Super Clone # 106L (Chlorination degree)
65% or more chlorinated ethylene-propylene copolymer) (Sanyo Kokusaku Pulp Co., Ltd.) Chlorinated hydrocarbon resin B: ADEKA chlorinated rubber CR-20 (chlorination degree)
65% or more chlorinated isoprene copolymer) Asahi Denka Co., Ltd.) Acrylonitrile copolymer A: Nipol # 1043 (acrylonitrile-butadiene copolymer) (Zeon Corporation) Acrylonitrile copolymer B: Nipol # 1072 ( Carboxylic acid group-containing acrylonitrile-butadiene copolymer) (Nippon Zeon Co., Ltd.) Table 2 below shows the results of a salt spray test conducted using the various coated members thus obtained.

In the salt spray test, the test was carried out for 5000 hours, but the condition of the coating film after 1,000 hours, 3000 hours, and 5000 hours, respectively, was the erosion depth, the rust condition of the coating film surface, and the blistering condition of the coating film. It was evaluated by. The erosion depth is expressed in mm, and the others are based on the following evaluation criteria (Note).

(Note) Salt spray test evaluation criteria: Examples 7 to 12 After dissolving the resin solid content compositions shown in Table 3 below in a solvent, they were made into paint in the same manner as in Examples 1 to 6 and applied to prepare test pieces, which were similarly sprayed with salt water. The tests were conducted, and the results are shown in Table 4 below.

Examples 13 to 18 The resin solid content compositions shown in Table 5 below were dissolved in a solvent, and then made into a paint in the same manner as in Examples 1 to 6, and this was applied to prepare a test piece, which was also sprayed with salt water. Tests were conducted and the results are shown in Table 6 below.

Comparative Examples 1 to 4 After dissolving the resin solid content compositions shown in Table 7 below in a solvent, they were made into paint in the same manner as in Examples 1 to 6, and this was applied to prepare test pieces, which were similarly sprayed with salt water. Tests were conducted and the results are shown in Table 8 below.

Comparative Example 5 A general commercial anticorrosive paint containing an epoxy ester-based resin as a main component was evaluated in the same manner as in Examples 1 to 6 and the results are shown below.
Shown in the table.

Comparative Example 6 The results of evaluation of a general commercially available anticorrosive paint containing a polyester resin as the main component in the same manner as in Examples 1 to 12 are shown in Table 8 below.

As shown above, it is clear that the coating films of the examples according to the present invention do not have a large erosion depth after the salt spray test and have excellent rust and blistering conditions as compared with the coating films of the comparative examples. is there.

〔The invention's effect〕

As is clear from the above description, when the coating material according to the present invention is applied to a zinc plated steel member, it has excellent adhesiveness to zinc plating, and also has excellent water vapor barrier property and moisture vapor barrier property. It does not cause cracks, peeling, blistering, shrinkage, etc. on the film, and because it synergizes with zinc plating, it is also excellent in rust prevention of metal parts, so it has a high degree of rust prevention that cannot be obtained with conventional paints. It is now possible to manufacture the steel members that it has.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobukatsu Kusunoki 3-4-4-403 Hiyodoridai, Kita-ku, Kobe-shi, Hyogo (72) Inventor Hironori Takamizo 4-4-1-18 Hisayo, Kawanishi-shi, Hyogo

Claims (5)

[Claims] 1. A) epoxy resin, B) chlorination degree of 60% by weight
Anticorrosion paint for zinc plated steel members containing the above chlorinated hydrocarbon elastomer and C) an acrylonitrile-butadiene copolymer and / or an acrylonitrile-butadiene copolymer partially having a hydroxy functional group or a carboxy functional group. Composition. 2. A) epoxy resin, B) chlorination degree of 60% by weight
Zinc plating coated with an anticorrosive coating composition containing the above chlorinated hydrocarbon elastomer and C) an acrylonitrile-butadiene copolymer and / or an acrylonitrile-butadiene copolymer partially having a hydroxy functional group or a carboxy functional group Steel member. 3. The proportion of the total coating resin solid content in 100 parts by weight of the coating composition is A) 5 to 70 parts by weight, B) 5 to 70 parts by weight, and C) 5
The anticorrosive coating composition according to claim 1, which comprises ˜70 parts by weight. 4. The ratio of the coating composition in 100 parts by weight of the total resin solid content is A) 5 to 70 parts by weight, B) 5 to 70 parts by weight, and C) 5
The zinc plated steel member according to claim 2, which is coated with an anticorrosive coating composition consisting of about 70 parts by weight. 5. The zinc plated steel member according to claim 2, wherein said steel member is subjected to zinc plating and then chromate treatment.