JP3560764B2 - Etching solution for polyamide resin - Google Patents

Description

【００２５】
【表２】

表１に示されるように、実施例１〜１４のエッチング液によりエッチング処理を施された基板は、いずれも金属被膜の密着性が４Ｂ以上であり、本発明のエッチング液がポリアミド樹脂の表面に十分なアンカー効果をもたらすことが確認された。
【００２６】
これに対して、表２に示されるように、無機酸および／またはギ酸の濃度が本発明からはずれるようなエッチング液、ギ酸を含まず無機酸のみを含有するエッチング液、有機酸としてギ酸以外の有機酸を含有するエッチング液、あるいは、無機酸を含まずギ酸と他の有機酸とからなるエッチング液によりエッチング処理を施された基板は、いずれも金属被膜の密着性が４Ｂ未満、もしくは、無電解めっきにより形成された金属被膜にふくれ（基板からの浮き）が発生し、実用に供し得ないものであった。
【００２７】
次に、実施例２および比較例５のエッチング液を用い、下記表３に示される４種のポリアミド樹脂基板に対して、上述と同様に銅被膜、ニッケル・リン被膜を形成し、基板と金属被膜の密着性を同様に評価した。その結果、表３に示されるように、実施例２のエッチング液によりエッチング処理を施された基板は、いずれも金属被膜の密着性が４Ｂ以上であり、本発明のエッチング液の使用対象となるポリアミド樹脂の範囲が広いことが確認された。
【００２８】
【表３】

【００２９】
【発明の効果】
以上詳述したように、本発明によればポリアミド樹脂用のエッチング液を、少なくとも無機酸を１．５〜６．０モル／ｌ、ギ酸を１．０〜１０モル／ｌの範囲で含有したエッチング液とするので、ポリアミド樹脂に対して、その表面にアンカー効果をもたらし、無電解めっきにより形成した金属被膜とポリアミド樹脂との密着性を高いものとすることができ、かつ、従来のエッチング液に比べて無電解めっきの対象となるポリアミド樹脂の範囲を拡大することができるという効果を奏する。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an etchant for a polyamide resin, and more particularly to an etchant used for an etching process for forming a metal film on a polyamide resin by electroless plating.
[0002]
[Prior art]
Polyamide resins have excellent mechanical properties, particularly excellent impact resistance, and are excellent in abrasion resistance, chemical resistance, oil resistance, gas barrier properties and the like, and are used for various applications. Focusing on the characteristics of such a polyamide resin, in recent years, by forming a metal coating on a molded article of a polyamide resin by an electroless plating method, a desired functional component is imparted by imparting conductivity or improving heat resistance. Or as a lightweight member instead of a metal member.
[0003]
On the other hand, the electroless plating method enables uniform deposition even on a complicated shaped surface having electrical insulation, and is used for forming a metal film on various substances. In the formation of a metal coating on a polyamide resin molded article by an electroless plating method, first, the surface of the polyamide resin is etched, and then the post-etching step, the catalyst application step, the reaction promoting step, and the electroless plating step are performed in this order. You. The etching treatment on the surface of the polyamide resin is performed for the purpose of forming fine irregularities on the surface of the polyamide resin, thereby providing an anchor effect, and increasing the adhesion of the metal film formed by electroless plating.
[0004]
[Problems to be solved by the invention]
Conventionally, hydrochloric acid, a mixed solution of hydrochloric acid and sulfuric acid, and the like have been used for the etching treatment of the polyamide resin. However, the adhesion of a metal film formed on a polyamide resin by electroless plating after performing an etching treatment with a conventional etching solution is not always sufficient. Further, depending on the type of the polyamide resin, the etching treatment is practically impossible, and there is a problem that formation of a metal film by electroless plating is hindered.
[0005]
The present invention has been made in view of the above circumstances, and an etching solution for a polyamide resin capable of performing an etching treatment for forming a metal film with high adhesion on various polyamide resins by electroless plating. The purpose is to provide.
[0006]
[Means for Solving the Problems]
In order to achieve such an object, the etching solution for a polyamide resin of the present invention contains at least 1.5 to 6.0 mol / l of an inorganic acid and 1.0 to 10 mol / l of formic acid. Configuration.
[0007]
Further, the etching solution for a polyamide resin of the present invention is configured such that the inorganic acid is at least one of hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an optimal embodiment of the present invention will be described.
[0009]
The etching solution for a polyamide resin of the present invention contains an inorganic acid in a range of 1.5 to 6.0 mol / l. When the content of the inorganic acid is less than 1.5 mol / l, the etching effect of the polyamide resin becomes insufficient, the adhesion of the metal film formed by the electroless plating becomes low, or the metal film swells (polyamide resin). Floating). On the other hand, when the content of the inorganic acid exceeds 6.0 mol / l, the etching of the polyamide resin becomes excessive, and the adhesion of the metal film formed by electroless plating also becomes low. Examples of the inorganic acid used include hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, and one or more inorganic acids can be used within the above concentration range.
[0010]
The formic acid constituting the etching solution for the polyamide resin of the present invention is contained in the range of 1.0 to 10 mol / l. If the formic acid content is less than 1.0 mol / l, the etching of the polyamide resin becomes insufficient, and the adhesion of the metal film formed by electroless plating is undesirably low. On the other hand, if the formic acid content exceeds 10 mol / l, the etching of the polyamide resin becomes excessive, and the adhesion of the metal film formed by electroless plating decreases.
[0011]
The temperature at the time of etching the polyamide resin using the etching solution of the present invention can be appropriately set in consideration of the type of the target polyamide resin, the bath composition of electroless plating, and the like. Can be set in a range. Further, the etching treatment can be performed by means such as an immersion method. For example, the immersion time in the immersion method can be appropriately set in a range of 1 to 30 minutes.
[0012]
The polyamide resin to be used as the etching solution for the polyamide resin of the present invention is a ring-opening polymer of a lactam such as ε-caprolactam, a polycondensate of an aminocarboxylic acid such as ω-aminoundecanoic acid, hexamethylenediamine and adipine. It is a polycondensate of a diamine such as an acid or sebacic acid and a dicarboxylic acid, or a copolymer thereof, or a mixture thereof, for example, 6-nylon, 11-nylon, 6,6-nylon, 6,10 -Nylon, 12-nylon, 4,6-nylon and the like. In addition, inorganic filler such as carbon filler, quartz, mica, titanium oxide, zinc white, alumina, magnesium hydroxide, sodium sulfate, calcium carbonate, magnesium silicate, calcium silicate, clay mineral, glass, etc., in the above polyamide resin. The present invention can also be applied to a polyamide resin containing an agent.
[0013]
【Example】
Next, the present invention will be described in more detail with reference to examples.
[0014]
First, a 36% aqueous solution of hydrochloric acid, a 96% aqueous solution of sulfuric acid, a 60% aqueous solution of nitric acid, and a 89% aqueous solution of phosphoric acid are prepared as inorganic acids, and the organic acids are a 76% aqueous solution of formic acid, a 99.5% aqueous solution of acetic acid, and a 99% aqueous solution of propionic acid. An aqueous solution was prepared, and an etching solution (Examples 1 to 14) in which these components were contained in a solvent (water) with a composition shown in Table 1 below, and a composition shown in Table 2 below were contained. Etching solutions (Comparative Examples 1 to 11) were prepared.
[0015]
Next, a 6-nylon substrate containing 30% by weight of a carbon filler was prepared, and this substrate was immersed in an etching bath at 40 ° C. using each of the above-mentioned etching solutions for 5 minutes to perform an etching treatment.
[0016]
Next, after washing, each substrate was immersed in a pre-dip bath (25 ° C.) in which the following components were contained in water as a solvent for 1 minute to perform a pre-dip treatment.
[0017]
Pre-dip bath composition , 36% hydrochloric acid aqueous solution… 30ml / l
・ Sodium chloride: 150g / l
Next, after washing, each substrate was immersed in a catalyst bath (25 ° C.) containing the following components in water as a solvent for 5 minutes to provide a palladium catalyst nucleus.
[0018]
Catalyst bath composition : 36% hydrochloric acid aqueous solution… 30 ml / l
・ Sodium chloride: 150g / l
・ Tin chloride: 3g / l
・ Palladium chloride… 0.1g / l
Next, after washing, each substrate was immersed in a 98% sulfuric acid 100 ml / l aqueous solution bath (40 ° C.) for 3 minutes to perform a reaction promoting treatment. After washing, each substrate is immersed in an electroless plating bath (bath temperature: 45 ° C.) containing water as a solvent and containing the following components for 15 minutes to perform electroless plating, thereby depositing a copper film on each substrate. I let it.
[0019]
Electroless plating bath composition , copper sulfate pentahydrate: 10 g / l
・ 37% HCHO… 10ml / l
・ EDTA4Na… 25g / l
・ 2-2′-bipyridine… 10ppm
Next, after washing, each substrate was immersed in a catalyst bath (25 ° C.) containing the following components in water as a solvent for 2 minutes to provide a palladium catalyst nucleus.
[0020]
Catalyst bath composition : 36% hydrochloric acid aqueous solution… 30 ml / l
・ Palladium chloride… 0.1g / l
Next, after washing, each substrate is immersed for 5 minutes in an electroless plating bath (bath temperature 60 ° C.) containing the following components in water as a solvent, and electroless plating is performed. -A phosphorus film was formed.
[0021]
Electroless plating bath composition , nickel sulfate hexahydrate: 26 g / l
・ Hypophosphorous acid… 25g / l
・ Malic acid… 15g / l
・ Lactic acid… 10g / l
・ Lead nitrate… 0.8ppm
For each substrate subjected to the electroless plating as described above, the adhesion to the metal film was evaluated by the following method, and the results are shown in Tables 1 and 2 below.
[0022]
Adhesion evaluation method of metal coating According to the cross-cut tape test method (ASTM D-3359), after cross-cutting the metal coating surface in a grid pattern, an adhesive tape (3M Corporation) ) Scotch tape) is applied, and the surface condition when the adhesive tape is peeled off is evaluated according to the following criteria. 4B or more is defined as a practically applicable adhesion.
[0023]
(Evaluation criteria)
5B: 0% of metal film peeling
4B: less than 5% of metal film peeling 3B: 5 to 15% of metal film peeling
2B: 15 to 35% of metal film peeling
1B: 35 to 65% of metal film peeling
0B: Exfoliation of metal film of 65% or more.
[Table 1]

[0025]
[Table 2]

As shown in Table 1, the substrates that were subjected to the etching treatment with the etching solutions of Examples 1 to 14 all had an adhesion of the metal film of 4B or more, and the etching solution of the present invention was applied to the surface of the polyamide resin. It was confirmed that a sufficient anchor effect was obtained.
[0026]
On the other hand, as shown in Table 2, as shown in Table 2, the concentration of the inorganic acid and / or formic acid is out of the range of the present invention, the etchant does not contain formic acid and contains only inorganic acid, and the organic acid is other than formic acid. Substrates that have been subjected to an etching treatment with an etching solution containing an organic acid or an etching solution containing formic acid and another organic acid without containing an inorganic acid all have an adhesion of a metal film of less than 4B or none. The metal film formed by the electrolytic plating was blistered (lifted from the substrate), which was not practical.
[0027]
Next, using the etching solutions of Example 2 and Comparative Example 5, a copper film and a nickel-phosphorous film were formed on the four kinds of polyamide resin substrates shown in Table 3 in the same manner as described above. The adhesion of the coating was similarly evaluated. As a result, as shown in Table 3, all of the substrates subjected to the etching treatment with the etching solution of Example 2 had an adhesion of the metal film of 4B or more, and were used for the etching solution of the present invention. It was confirmed that the range of the polyamide resin was wide.
[0028]
[Table 3]

[0029]
【The invention's effect】
As described above in detail, according to the present invention, the etching solution for a polyamide resin contains at least 1.5 to 6.0 mol / l of an inorganic acid and 1.0 to 10 mol / l of formic acid. Since the etching solution is used, an anchor effect is provided on the surface of the polyamide resin, the adhesion between the metal film formed by electroless plating and the polyamide resin can be increased, and the conventional etching solution can be used. As a result, the range of the polyamide resin to be subjected to the electroless plating can be expanded.

Claims (2)

An etching solution for a polyamide resin, comprising at least 1.5 to 6.0 mol / l of an inorganic acid and 1.0 to 10 mol / l of formic acid. The etchant according to claim 1, wherein the inorganic acid is at least one of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid.