JP5194488B2 - Metal surface treatment coating liquid and method for producing surface treated metal parts - Google Patents

Description

  The present invention relates to a coating solution for treating a metal surface, and more specifically, a metal surface capable of imparting excellent characteristics to metal parts by treating the metal surface with polyphenylene sulfide which is an engineering plastic. The present invention relates to a treatment coating liquid and a method for producing a surface-treated metal part.

  Metals or metal parts are generally used as raw materials for various devices, and the surfaces of these metals are covered with a resin to impart functions such as corrosion resistance and adhesion.

  In addition, polyphenylene sulfide (hereinafter sometimes abbreviated as PPS), which is one of engineering plastics, has excellent mechanical properties, thermal properties, electrical properties, and chemical properties, and functions of various devices. Widely used as structural parts and structural parts.

  And the proposal as a powder coating material is made | formed so that the outstanding property may be utilized (for example, refer patent documents 1-4).

JP 05-117588 A Japanese Patent Laid-Open No. 05-293439 JP 05-295300 A Japanese Patent Laid-Open No. 05-295301

  However, engineering plastics, which are high-performance resins, have problems such as difficulty in dissolving in solvents and low adhesion to metal surfaces due to their high stability. Among them, PPS has excellent chemical properties as proposed in Patent Documents 1 to 4, but is hardly dissolved in a solvent, so that it can be developed as a coating solution with excellent handleability. It was something that was n’t tangled.

  Therefore, the present invention provides a coating solution for metal surface treatment that is excellent in handleability and can impart an excellent function to a metal, and a method for producing a surface-treated metal component using the same. .

  As a result of intensive studies on the above problems, the present inventors have found that a solution containing a specific PPS can be a coating solution for metal surface treatment, and have completed the present invention.

That is, the present invention is 2 to 30 wt% PPS oligomer Ri Na dissolved in an organic solvent, the weight average molecular weight in terms of polystyrene the PPS oligomer was measured by gel permeation chromatography of 10,000 or less The present invention relates to a coating solution for metal surface treatment, which is a PPS oligomer .

  The present invention is described in detail below.

  The coating solution for metal surface treatment of the present invention is a solution obtained by dissolving 2 to 30% by weight of a PPS oligomer in an organic solvent, and particularly 3 to 10% by weight because a uniform coating film can be formed. It is preferable to dissolve the PPS oligomer. Here, when the PPS oligomer is less than 2% by weight, it is difficult to form a coating film because the concentration of the coating solution is too low. On the other hand, when it exceeds 30% by weight, the PPS oligomer is difficult to dissolve and it becomes difficult to form a uniform coating film.

  The PPS oligomer referred to in the present invention is a low molecular weight substance of PPS generally referred to as an oligomer and is soluble in an organic solvent, and particularly in terms of polystyrene measured using gel permeation chromatography. A PPS oligomer having a weight average molecular weight of 10,000 or less is preferable. Here, in the case of other than the PPS oligomer, that is, PPS, generally available PPS cannot be used as a coating liquid because it hardly exhibits solubility in a solvent or a solvent. Moreover, since PPS is stable and has a low polarity, it is difficult to form a strong coating film with poor adhesion to metal. On the other hand, the PPS oligomer is a low molecular weight substance that is unstable and has a large polarity, and exhibits strong adhesion to a metal when formed into a coating film.

  As a method for obtaining the PPS oligomer constituting the present invention, any method can be used as long as the PPS oligomer can be obtained. For example, alkali metal sulfide is used in a polar organic solvent known as a method for producing PPS. And a method of polymerizing a product and a dihaloaromatic compound in a super-dilute concentration region. Furthermore, it is also possible to recover from PPS obtained by the above general production method by performing extraction using methylene chloride, acetone, NMP or the like as an extraction solvent.

  As the organic solvent constituting the coating solution for metal surface treatment of the present invention, any organic solvent capable of dissolving the PPS oligomer can be used, for example, N-methyl-2- Examples include pyrrolidone, 1-cyclohexyl-2-pyrrolidone, methylene chloride, acetone, dimethylformamide, dimethylacetamide, chloroform, carbon tetrachloride, methanol, ethanol, kerosene, etc. Among them, metal surface treatment showing excellent handling properties It is preferable that it is at least one selected from the group consisting of N-methyl-2-pyrrolidone, 1-cyclohexyl-2-pyrrolidone, methylene chloride, acetone, dimethylformamide, dimethylacetamide and chloroform. .

  The coating solution for metal surface treatment of the present invention can be produced by dissolving a PPS oligomer in an organic solvent.

  The metal surface treatment coating liquid of the present invention is in a liquid state and can be used by simple coating. For example, the metal surface treatment coating liquid is applied to a metal part, and the surface of the metal part After the PPS oligomer is attached to the substrate, it is possible to produce a more effective surface-treated metal part by processing at a temperature of 150 to 250 ° C. in an oxygen-containing atmosphere. At this time, the adhesion of the PPS oligomer to the surface of the metal part may be a PPS oligomer solution or a dried PPS oligomer alone, and among them, the treatment at a temperature of 150 to 250 ° C. in the following oxygen-containing atmosphere. Is more efficient, it is preferable to dry the PPS oligomer alone. Moreover, it becomes possible to perform the hardening reaction of a PPS oligomer by processing at 150-250 degreeC by oxygen containing atmosphere, As a result, formation of the PPS film which has strong adhesiveness on the metal component surface is attained. Any oxygen-containing atmosphere can be used as long as it contains oxygen in a range that allows the PPS oligomer to be cured, and examples thereof include oxygen and air.

  In this case, the metal constituting the metal part may be made of any metal, and examples thereof include aluminum, aluminum alloy, magnesium, magnesium alloy, titanium alloy, copper, and copper alloy.

  The metal part treated with the coating solution for metal surface treatment of the present invention is coated with PPS having excellent characteristics as an engineering plastic, and therefore exhibits excellent corrosion resistance. In addition, the adhesiveness with PPS also shows strong adhesiveness.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

-Measurement of weight average molecular weight of PPS oligomer-
Measurement was carried out as a polystyrene equivalent value by ultra high temperature gel permeation chromatography. The measurement conditions are as follows.
Solvent: 1-chloronaphthalene Sample concentration: 0.2% by weight
Sample flow rate: 1 ml / min Column temperature: 210 ° C
Column packing: Polystyrene gel detector: UV detector (UV absorption wavelength: 360 nm)
-Evaluation of adhesion at the interface between metal parts and PPS layer-
An adhesive tape was applied to the surface of the obtained PPS-coated metal part, and evaluation was performed based on the peeled state of the PPS layer when the adhesive tape was peeled off. As the evaluation criteria, the case where only the adhesive tape is peeled off and the PPS layer covers the surface of the metal part is considered good coating, and the case where the PPS layer adheres to the adhesive tape and the surface of the metal part is removed is applied. It was assumed that the work was defective.

~ Evaluation of corrosion resistance of metal parts ~
Corrosion resistance was evaluated by suspending a 0.1N hydrogen chloride aqueous solution on the surface of the obtained PPS coated metal part, leaving it for 2 weeks and observing the surface condition.

Synthesis example 1
A 50 liter autoclave equipped with a stirrer was charged with 621 g of Na ₂ S · 2.9H ₂ O and 16.7 liters of N-methyl-2-pyrrolidone, gradually heated to 205 ° C. while stirring under a nitrogen stream, and 135 g Of water was distilled off. After the system was cooled to 140 ° C., 716 g of p-dichlorobenzene and 5000 g of N-methyl-2-pyrrolidone were added, and the system was sealed under a nitrogen stream. This system was heated to 225 ° C. over 2 hours and polymerized at 225 ° C. for 2 hours, then heated to 250 ° C. over 30 minutes, and further polymerized at 250 ° C. for 3 hours. After completion of the polymerization, the mixture was cooled to room temperature and subjected to solid-liquid separation using a centrifuge.

  The liquid was poured into distilled water, a diluted hydrochloric acid aqueous solution was added to reprecipitate the PPS oligomer, and the PPS oligomer was recovered by filtration and dried.

  On the other hand, the solid content was repeatedly washed with warm water and dried at 100 ° C. for a whole day and night to obtain PPS containing a PPS oligomer. And 15 liters of N-methyl-2-pyrrolidone heated at 80 degreeC was prepared, and obtained PPS was thrown in and stirred. Thereafter, filtration was carried out under the temperature condition of 80 ° C., and an N-methyl-2-pyrrolidone solution was recovered. The N-methyl-2-pyrrolidone solution was poured into distilled water, a diluted aqueous hydrochloric acid solution was added to reprecipitate the PPS oligomer, and the PPS oligomer was recovered by filtration and dried.

  After combining each PPS oligomer, its weight average molecular weight was measured and found to be 7000.

Example 1
The PPS oligomer obtained in Synthesis Example 1 was dissolved in methylene chloride at a concentration of 5% by weight to obtain a coating solution.

  A test piece (50 mm (long side) × 20 mm (short side) × 3 mm (thickness)) made of an aluminum alloy (A1100) was immersed in the coating solution, and then the surface of the test piece was covered with a PPS oligomer by air drying. Thereafter, the PPS oligomer was cured by leaving it in a dryer (in an air atmosphere) heated to 250 ° C. for 2 hours to obtain a test piece coated with PPS.

  When the interfacial adhesiveness of the obtained test piece was evaluated, the PPS layer was not peeled off. Further, no corrosion was confirmed in the corrosion resistance evaluation.

Example 2
The PPS oligomer obtained in Synthesis Example 1 was dissolved in acetone at a concentration of 3% by weight to obtain a coating solution.

  An aluminum test piece (50 mm (long side) × 20 mm (short side) × 3 mm (thickness)) was immersed in the coating solution, and then the surface of the test piece was covered with a PPS oligomer by air drying. Thereafter, the PPS oligomer was cured by leaving it in a dryer (in an air atmosphere) heated to 230 ° C. for 3 hours to obtain a test piece coated with PPS.

  When the interfacial adhesiveness of the obtained test piece was evaluated, the PPS layer was not peeled off. Further, no corrosion was confirmed in the corrosion resistance evaluation.

Example 3
The PPS oligomer obtained in Synthesis Example 1 was dissolved in N-methyl-2-pyrrolidone at a concentration of 8% by weight to obtain a coating solution.

  A magnesium test piece (50 mm (long side) × 20 mm (short side) × 3 mm (thickness)) is immersed in the coating solution, and then left in a dryer (in an air atmosphere) heated to 240 ° C. for 2 hours. Then, the PPS oligomer was cured to obtain a test piece coated with PPS.

  When the interfacial adhesiveness of the obtained test piece was evaluated, the PPS layer was not peeled off. Further, no corrosion was confirmed in the corrosion resistance evaluation.

Comparative Example 1
The PPS obtained in Synthesis Example 1 was heated and melted at 280 ° C., and a test piece (50 mm (long side) × 20 mm (short side) × 3 mm (thickness)) made of aluminum alloy (A1100) was immersed in the molten PPS. A test piece coated with PPS was obtained.

  When the interface adhesiveness of the obtained test piece was evaluated, the PPS layer peeled off. Corrosion was also confirmed in the corrosion resistance evaluation due to the penetration of the aqueous hydrogen chloride solution from the interface with weak adhesion.

Claims (4)

2-30% by weight of polyphenylene sulfide oligomer is dissolved in an organic solvent, and the polyphenylene sulfide oligomer is a polyphenylene sulfide oligomer having a polystyrene-reduced weight average molecular weight of 10,000 or less as measured using gel permeation chromatography. A metal surface treatment coating solution characterized by that. The organic solvent according to claim 1 is at least one selected from the group consisting of N-methyl-2-pyrrolidone, 1-cyclohexyl-2-pyrrolidone, methylene chloride, acetone, dimethylformamide, dimethylacetamide, and chloroform. The metal surface treatment coating solution according to claim 1, which is an organic solvent. The metal surface treatment coating solution according to claim 1 or 2 is applied to a metal part, and after the polyphenylene sulfide oligomer is adhered to the surface of the metal part, the treatment is performed at 150 to 250 ° C. in an oxygen-containing atmosphere. A method for producing a surface-treated metal part. The method for producing a surface-treated metal part according to claim 3, wherein the metal part is a metal part selected from the group consisting of aluminum, aluminum alloy, magnesium, magnesium alloy, titanium alloy, copper and copper alloy.