JP2020111765A - Hydrophilization treatment agent for metal plate, and hydrophilization treatment method using the same - Google Patents

Abstract

To improve hydrophilicity remarkably in comparison with a prior art by performing, by one-time hydrophilization treatment, a defatting treatment and a wettability improvement treatment which are performed hitherto by being divided into two steps, as coating of a metal plate or a pretreatment for plating.SOLUTION: A hydrophilization treatment agent for a metal plate comprises following compositions, (a) inorganic alkali, (b) a chelate agent and (c) a surfactant comprising polyoxyalkylene alkyl ether having a surface tension of 30 mN/m or less. Execution of a hydrophilization treatment of the metal plate by using the hydrophilization treatment agent is provided. Further, a coating treatment/plating method for performing for coating or plating the metal plate subjected to the hydrophilization treatment is also provided.SELECTED DRAWING: None

Description

The present invention improves the adhesion of a coating film or a plating film by hydrophilicizing the metal plate to improve wettability as a pretreatment for coating or plating a metal plate such as iron or non-ferrous metal. The present invention relates to a hydrophilic treatment agent for a metal plate and a hydrophilic treatment method using the same.

When painting or plating a metal plate such as ferrous or non-ferrous metal, if a small amount of organic matter remains on the metal surface, a phenomenon called cissing may occur, in which the coating solution or plating solution is repelled. There is. In this case, a uniform coated surface or plated surface cannot be obtained, which is a serious problem in practical use.
Even if cratering does not occur, if minute organic matter remains on the metal surface, minute organic matter will be present between the coating film or plating film and the metal plate. There is a problem that the coating film is not sufficiently adhered and thus the coating film is easily peeled off.

Particularly in recent years, there is an increasing need for long-term reliability of products, and it is necessary to improve the adhesion of coating films and plating films more than ever. Further, in the photolithography technology in semiconductor manufacturing, a high quality coating film is required, and a high quality coating film that can be precisely processed even in ultrafine photoetching is required.

Conventionally, when a metal surface is coated or plated, degreasing treatment and wettability improving treatment are performed as pretreatments.
That is, in the degreasing treatment, the metal surface is washed with a degreasing cleaning liquid such as caustic alkali. However, the surface wettability of the metal plate is not improved only by degreasing and cleaning, and therefore, surface treatment for improving the surface wettability is required. Then, in the wettability improving treatment, a method of decomposing minute organic substances and the like remaining on the metal surface by oxygen plasma and introducing a hydrophilic functional group to the metal surface, or a blasting treatment in which an abrasive is injected into the metal surface A method of polishing/removing a metal surface together with minute organic substances to enhance the adhesion force such as coating in combination with the anchor effect of the surface has been adopted.

The conventional coating/plating pretreatment technology is complicated and time-consuming because it is performed in two steps of degreasing treatment and wettability improvement treatment. Therefore, we provide a technology to simplify the process and make the metal surface hydrophilic in one treatment. Was desired. That is, in the pretreatment before coating or plating the metal surface, it is necessary to remove minute organic substances remaining on the metal surface in one treatment to make the metal surface hydrophilic to an extent suitable for coating or plating treatment. Is. It is a problem to be solved by the present invention to solve such a problem and to provide a new hydrophilic treatment agent and a hydrophilic method for a metal plate.

In order to solve the problems of the prior art, the present invention provides a hydrophilic treatment agent having the following composition, and a hydrophilic treatment method using the same.
(1) Hydrophilizing agent for a metal plate having the following components (a) an inorganic alkali, (b) a chelating agent, and (c) a surface tension agent having a surface tension of 30 mN/m or less (2) the above (a) Hydrophilic treatment agent for metal plates, wherein the inorganic alkali is NaOH or KOH (3) A metal plate characterized in that the chelating agent in (b) above is an alkali salt of phosphoric acid or phosphonic acid. Hydrophilizing agent.
(4) The hydrophilizing agent for a metal plate, wherein the alkali salt of phosphoric acid or phosphonic acid in (b) above is an alkali salt of etidronic acid (5) The surfactant in (c) above is polyoxy A hydrophilizing agent for a metal plate, which is an alkylene alkyl ether.
(6) A method for hydrophilizing a metal plate, which comprises applying the hydrophilizing agent described in (1) to (5) to the metal plate.
(7) A coating method, which comprises applying a coating material to a metal plate that has been subjected to the hydrophilic treatment by the hydrophilic treatment method described in (6).
(8) A plating method which comprises plating a metal plate hydrophilically treated by the hydrophilic treatment method described in (6).
(9) A surface treatment method for a lead frame, which comprises subjecting the lead frame to a hydrophilic treatment by the hydrophilic treatment method described in (6) and then performing plating or coating treatment.

According to the present invention, before performing coating or plating treatment on ferrous or non-ferrous metal, degreasing and wettability improvement conventionally performed as pretreatment are performed once by using the hydrophilic treatment agent according to the present invention. It can be done by processing. It was also found that the degree of hydrophilization was remarkably improved as compared with degreasing using NaOH and cleaning using an existing cleaning agent. This point will be shown in the following examples.

In developing the hydrophilic treatment agent of the present invention, the starting point of its composition was the glass detergent for a display that the applicant has already developed. Hereinafter, this cleaning agent is referred to as an existing cleaning agent.
This existing cleaning agent is a composition containing an inorganic alkali, a chelating agent, a surfactant, a solubilizing agent for the surfactant, and pure water.

This existing cleaning agent was used as the starting point for the development of the hydrophilic treatment agent for metal plates. Since this cleaning agent contains potassium hydroxide as an inorganic alkali, a degreasing action of fine organic substances on the metal surface can be expected. However, since the chelating agent has an action of dispersing the particle dirt in the detergent, the effect of washing the metal surface can be expected.
In addition, since the foaming of the cleaning agent is extremely disliked in the cleaning of the glass to be cleaned by the existing cleaning agent, a surfactant having a particularly low foaming property is adopted.

In utilizing the composition of the above existing cleaning agent as a hydrophilic treatment agent for metal surface, the present inventors have searched for an optimum compound for each constituent component from the viewpoint of the hydrophilic treatment agent for metal surface. did. Specifically, in order to promote the exfoliation of minute organic substances remaining on the metal surface, the hydrophilic treatment agent is constituted by a composition comprising constituents having an action of reducing the contact angle of the metal surface after treatment. Therefore, we considered that it is effective, and conducted a study in the direction of selecting a constituent having such a function.

First, the chelating agent was examined.
The contact angle was measured when a metal plate to be treated (pure iron: SS400) was treated with various phosphoric acid or phosphonic acid chelating agents. That is, ADEKA NOL B-787S, which is generally used as a detergent surfactant, is used as a temporary surfactant, and various chelating agents are dissolved in a solution prepared by dissolving it to 4.8% by weight. A solution obtained by diluting the solution to 5 wt% was used as a test solution, and a metal plate was treated with the test solution.
The specific content of the treatment is to immerse the metal plate in each test solution for 5 to 10 minutes, remove the metal plate and dry it with warm air, and then drop water drops on the surface of the metal plate to measure the contact angle. .. Samples 1 to 9 were treated with various test solutions.

Table 1 shows the type of chelating agent used in each test solution and the contact angles of the treated metal plates of Samples 1 to 9 treated with the chelating agent. For sample 7 (treated with ethylenediaminetetraacetate solution), sample 8 (treated with potassium hydroxide), and sample 9 (not treated), the contact angles measured for comparison are shown for comparison.

From the results in Table 1, it was found that tripotassium phosphate, potassium pyrophosphate, sodium tripolyphosphate, sodium tetraphosphate, sodium hexametaphosphate, and potassium etidronate are suitable as the chelating agent.
That is, the metal plates (Samples 1 to 6) treated with these chelating agents are equivalent to or more than Samples 8 (treated with ethylenediaminetetraacetic acid) and Sample 9 (treated with potassium hydroxide only). It was revealed that it is possible to reduce the contact angle on the metal surface. Further, among the phosphoric acid and phosphonic acid chelating agents, Sample 6 treated with a solution using etidronic acid can minimize the contact angle, and therefore, as a constituent of the metal plate hydrophilizing agent, It turned out to be the most preferred chelating agent.

Since etidronic acid was found to be most suitable as the chelating agent used in the present invention, next, to clarify what is suitable as the surfactant to be added to the hydrophilic treatment agent of the present invention, The test was carried out using various surfactants.

A contact angle measurement test was performed using the following surfactants. The surfactants used in the tests and investigations and their sources are as follows. All of these surfactants are polyoxyalkylene alkyl ethers (excluding ADECATOL SP-12 and ADECANOL B-787S for control). Below, each surfactant is described only by its symbol.

EMALEX 640 (Japan Emulsion Co., Ltd.)
Same as above (same as above)
Same as above 120 (Same as above)
Ibid 115 (ibid)
ADEKA TOL SO-145 (ADEKA Corporation)
Neugen TDS-80 (Daiichi Kogyo Seiyaku Co., Ltd.)
Neugen XL-80 (same as above)
Same as above 60 (Same as above)
Neugen SD-70 (same as above)
Same as above 60 (Same as above)
Neugen EA-137 (same as above)
ADEKA TOL SP-12 (ADEKA Corporation)
ADEKA NOL B-787S (same as above)
ADEKA NOL B-4009 (same as above)
Fine Surf 9161 (Aoki Yushi Kogyo Co., Ltd.)
ADEKA NOL AS-054C (Daiichi Kogyo Seiyaku Co., Ltd.)
Fine Surf D-1305 (Aoki Yushi Kogyo Co., Ltd.)

To measure the contact angle, dilute an aqueous solution of potassium hydroxide 8.4 wt% and etidronic acid (60%aq) 6.7 wt% to 5%, and add the above-mentioned various surfactants to this to a concentration of 0.2%. To obtain a treatment liquid. SUS304 was dipped in this treatment solution and surface treatment was performed for 10 minutes while maintaining the test temperature at 50°C. After that, the plate to be treated was dried, water drops were dropped on the surface, and the contact angle was measured. In addition, the HLB values of the above-mentioned various surfactants themselves and the surface tension (ST (20° C.)) at 20° C. are also summarized in Table 2.

Here, the HLB value is a value representing the degree of affinity of the surfactant for water and organic substances insoluble in water. It takes a value from 0 to 20, and the closer to 0, the higher the lipophilicity, and the closer to 20, the higher the hydrophilicity. The surface tension is a force that acts on a liquid to minimize its surface area, and has a value of 476.00 for mercury and 72.75 mN/m for water.
In selecting a surfactant having a function of reducing the contact angle on the surface of a metal plate, the properties considered to be related to this function are the HLB value and the surface tension (ST (20°C)). In order to determine which property to select the surfactant based on, the relationship between each property and the contact angle of the treated metal substrate was investigated. The results are summarized in Table 2.

Adecanol B-787S may be used as a surfactant in the glass detergent. However, as is clear from Table 2, even if the metal plate was treated with B-787S, the contact angle after the treatment could be 76.5°.
Therefore, the present inventors first examined which property of the HLB value and the surface tension (ST (20° C.)) should be used to select the surfactant. Although the details are omitted as a result of the statistical processing of the data in Table 2, the contact angle of the metal plate after the processing has a strong correlation with the surface tension data of the surfactant, not the HLB value data. Was confirmed.
Therefore, it is effective to select a surfactant having a low surface tension, and particularly a surfactant having a surface tension of 30 mN/m or less is selected. This is because in Table 2, TDS-80, XL-80, 60, SD-70, -60, AS-054C and D1305 satisfy this condition, but the contact angle is 43 to 58°. .. These surfactants achieve low contact angles that cannot be achieved with other surfactants. In particular, Neugen XL-80 and XL-60 achieved the lowest contact angle (less than 47°) among the investigated surfactants, and thus were found to be the most preferred surfactants. ..
When adding the surfactant, it is preferable to add a solubilizer in order to improve the solubility.

As a result of the above examination, it became clear that a composition suitable as a hydrophilic treatment agent for a metal plate is composed of the following components. That is, it is a composition comprising (a) an inorganic alkali such as NaOH or KOH, (b) a chelating agent which is phosphoric acid or phosphonic acid such as etidronic acid, and (c) a surfactant having a surface tension of 30 mN/m or less. ..

The hydrophilic treatment agent according to the present invention can be expected to be utilized in a wide range of technical fields. Specifically, it can be used as a pretreatment agent when performing coating treatment or phosphoric acid film formation. In addition to this, it can be used as a pretreatment agent for metal plating and a pretreatment agent for plating/painting copper-based materials for lead frames.
Moreover, even if the metal plate is subjected to the hydrophilic treatment, the hydrophilic treatment can be performed on various metals. Specific effects have been confirmed for aluminum, aluminum alloys, iron, iron-based alloys, copper, copper-based alloys, zinc, titanium and the like.

In order to specifically confirm the effect of the present invention, cleaning composition I to VII (hereinafter, treatment liquids I to VII) shown in Table 3 was prepared, and various characteristics were measured and evaluated.
Treatment liquid I is an example that satisfies all the constituent requirements of the present invention, and treatment liquids II to VII are comparative examples that do not satisfy one or more requirements. The reason for the comparison example is as follows. Here, the solubilizer is added as necessary to improve the solubility of the surfactant, and does not constitute an essential requirement of the present invention.
In the following, the content of the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

但し、HEDPはエチドロン酸、EDTAはエチレンジアミン四酢酸を表す。
処理液II：キレート剤がリン酸、ホスホン酸ではなく、一般に使用されるEDTAを使用。
処理液III：界面活性剤（B-4009）の表面張力が47.0ｍN／ｍであり30以下ではない。
処理液IV：キレート剤を配合していない。
処理液V：KOHがHEDPにより中和されてフリーのKOHは存在しない。
処理液VI：界面活性剤を添加していない。

処理液II〜VIは、本発明の親水化処理剤の3つの必須成分のいずれかを含有していない点で、本発明の従来技術に相当する。 The compositions of the respective processing liquids I to VII are summarized in Table 3 below.

However, HEDP represents etidronic acid and EDTA represents ethylenediaminetetraacetic acid.
Treatment liquid II: The commonly used EDTA is used as the chelating agent instead of phosphoric acid and phosphonic acid.
Treatment liquid III: The surface tension of the surfactant (B-4009) is 47.0 mN/m, which is not 30 or less.
Treatment liquid IV: No chelating agent is added.
Treatment solution V: KOH is neutralized by HEDP and free KOH does not exist.
Treatment liquid VI: No surfactant was added.

The treatment liquids II to VI correspond to the prior art of the present invention in that they do not contain any of the three essential components of the hydrophilic treatment agent of the present invention.

Using the treatment liquids of the above Examples and Comparative Examples, the contact angles of the metal plates after treating various metal plates were measured. In the measurement of the contact angle, after the surface of the plate to be treated is pickled, the plate to be treated is polished with sandpaper in the order of 200, 1000 and 2000 mesh, and the plate is immersed in various treatment liquids at room temperature for 10 minutes, This was taken out, shower rinsed, and then dried with warm water to measure the contact angle.

Stainless steel (SS304) was treated with a 5% dilution of the treatment liquid in Table 3. A test piece was prepared by immersing it in a treatment liquid at 25° C. for 5 minutes, rinsing it with a shower and then drying it with warm air.
Table 4 shows the results of measuring the contact angle by dropping water droplets on the surface of the obtained test body and by the above-mentioned measuring method.

The contact angle of the untreated plate was 95.2° because many minute organic substances remained on the stainless steel before the treatment with the treatment liquid. However, by applying the hydrophilic treatment agent (treatment liquid I) of the present invention to stainless steel, the contact angle can be reduced to 32.8°. Therefore, it can be seen that the hydrophilic property is remarkably improved even when compared with the case of cleaning with the conventional cleaning agents (treatment liquids II to VI).

The same treatment as in Example 1 was performed on pure iron (SS400).

When the hydrophilic treatment agent of the present invention was used, the contact angle could be reduced and the hydrophilicity could be improved even when the plate to be treated was pure iron, as in the case of stainless steel. The difference in the effect is clear as compared with the case of treating with the treatment liquid III which does not use a surfactant having a surface tension of 30 mN/m or less.

The same process was performed on the copper material for the lead frame.
The treatment liquid diluted to 5% was kept at 50° C., the copper material amount was immersed for 5 minutes, then rinsed with a shower and dried with warm air. Then, the contact angle was measured by the method described above. The copper material used was KFC manufactured by Kobe Steel.

リードフレーム用銅材料についても純鉄やステンレス鋼におけると同様の効果を確認することができた。

With regard to the copper material for the lead frame, the same effect as with pure iron or stainless steel could be confirmed.

銅（C1100P）についても純鉄やステンレス鋼におけると同様の効果を確認することができた。 The same treatment as in Example 3 was performed on copper (C1100P), and the contact angle was measured.

With copper (C1100P), the same effects as with pure iron and stainless steel could be confirmed.

According to the hydrophilizing agent and the hydrophilizing method of the present invention, the metal plate surface is remarkably excellent in hydrophilicity as compared with the pretreatment which is conventionally performed before the coating or plating treatment is performed on the metal plate surface. Can be given to. Further, as a pretreatment for coating/plating, conventionally, two steps of degreasing cleaning and wettability improving treatment were required, but according to the hydrophilizing treatment agent and the hydrophilizing treatment method of the present invention, one hydrophilizing treatment is performed. Since the pretreatment can be performed by the treatment, the working efficiency is remarkably improved.

Claims (9)

A hydrophilic treatment agent for a metal plate having the following components.
(A) inorganic alkali,
(B) chelating agent, and
(C) Surfactant having a surface tension of 30 mN/m or less The hydrophilic treatment agent for a metal plate according to claim 1, wherein the inorganic alkali of (a) is NaOH or KOH. The hydrophilic treatment agent for a metal plate according to claim 1, wherein the chelating agent (b) is an alkaline salt of phosphoric acid or phosphonic acid. The hydrophilic treatment agent for a metal plate according to claim 3, wherein the alkali salt of phosphoric acid or phosphonic acid is an alkali salt of etidronic acid. The hydrophilic treatment agent for a metal plate according to claim 1, wherein the surfactant (c) is a polyoxyalkylene alkyl ether. A method for hydrophilizing a metal plate, which comprises applying the hydrophilizing agent according to any one of claims 1 to 5 to a metal plate to surface-treat the metal plate. A coating treatment method, wherein a coating material is applied to a metal plate that has been hydrophilically treated by the hydrophilic treatment method according to claim 6. A plating method, comprising: plating a metal plate hydrophilically treated by the hydrophilic treatment method according to claim 6. A surface treatment method for a lead frame, which comprises subjecting the lead frame to a hydrophilic treatment by the hydrophilic treatment method according to claim 6 and then applying a coating or plating treatment.