JPH0449859B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a novel conductive polyamide molded article and a method for producing the same. BACKGROUND OF THE INVENTION Electroconductivity has traditionally been imparted to polyamide molded articles mainly by electroless plating. However, the electroless plating method requires degreasing treatment, chemical etching treatment, sensitization treatment, activation treatment,
In addition to the major disadvantage of being extremely complicated as it requires electroless plating and a large number of processing steps, it also has the disadvantage of poor adhesion of the resulting metal coating. It has been disclosed that the latter of these drawbacks can be improved by devising pretreatment (Japanese Patent Application Laid-open No. 161432/1982), blending silica into polyamide (Japanese Patent Application Laid-open No. 158236/1982), etc. Regarding the former, no improvements have been made. On the other hand, it has been disclosed that conductivity can be imparted by coordinating a monovalent copper salt to the cyano group of a nitrile resin such as polyacrylonitrile (JP-A-56-112909, JP-A-58- No. 45263). The present inventor conducted research with the aim of eliminating the drawbacks of the electroless plating method and forming a conductive film with excellent adhesion on polyamide molded products by a simple method, and tried the method using the above-mentioned nitrile resin. However, it was found that this method could not be applied to polyamide because the monovalent copper salt was not coordinated. In order to achieve the above object, the inventor continued further intensive research.
As a result, by activating the amide group on the polyamide molded product, coordinating divalent copper ions, and reducing this to monovalent with a sulfur-containing reducing agent, the purpose could be achieved and new conductivity could be achieved. It has been found that polyamide molded articles can be obtained. The present invention was completed based on the above findings. Structure of the Invention The present invention provides a conductive material characterized in that a cuprous sulfide coating is closely formed on the surface of a polyamide molded product through coordination bonds between the amide groups of the polyamide molded product and cuprous sulfide. and the activation of the amide group using at least one selected from iodine, bromine, potassium iodide, sodium iodide, lithium iodide, potassium bromide, sodium bromide, lithium bromide, and a phenol compound. The polyamide molded product subjected to the chemical treatment is treated with a divalent copper ion solution, and then brought into contact with a sulfur-containing reducing agent to reduce the copper ion to monovalent, and the polyamide molded product is coated on the surface of the polyamide molded product. The present invention relates to a method for manufacturing a conductive polyamide molded article, characterized in that a cuprous sulfide coating is formed in close contact with the amide group and cuprous sulfide through coordination bonds. The conductive polyamide molded product of the present invention has a cuprous sulfide coating formed in close contact with the surface of the polyamide molded product through coordination bonds between the amide groups of the polyamide molded product and cuprous sulfide. . The thickness of the cuprous sulfide coating in the present invention is not particularly limited, but is usually about 0.01 to 50 μm. The cuprous sulfide coating has extremely excellent adhesion and is also excellent in cold resistance and heat resistance. Furthermore, since the cuprous sulfide coating uniformly covers the surface of the polyamide molded product, its conductivity is extremely stable. The conductive polyamide molded article of the present invention is manufactured, for example, as follows. Polyamide molded articles in the present invention include films, fibers, etc. of polymers having amide groups, such as polyamide-6, polyamide-6,6, polyamide-6,10, polyamide-11, polyamide-12,
These include cloth, or molded bodies of various shapes such as rectangular parallelepipeds, cylinders, and spheres. Further, the molded article may have a multilayer structure of a resin other than polyamide and polyamide, or a mixture thereof. First, a polyamide molded article is subjected to an amide group activation treatment. This activation treatment weakens the strong hydrogen bonds existing between amide groups to allow divalent copper ions to coordinate. In this activation treatment, iodine, which has the property of entering between amide groups,
Bromine, potassium iodide, sodium iodide, lithium iodide, potassium bromide, sodium bromide, and phenols that have the property of swelling polyamides, ortho-cresol, metacresol, para-cresol, orthochlorophenol, ketochlorophenol, para- It is preferable to use at least one phenol compound such as chlorophenol or xylenol. Particularly preferred among these are the combination of a halogen selected from iodine and bromine with a halogen compound selected from potassium iodide, sodium iodide, lithium iodide, potassium bromide, sodium bromide, and lithium bromide, or phenol. It is a compound. In addition, this activation treatment is performed on a polyamide molded product of an aqueous solution of at least one of the above-mentioned iodine, bromine, potassium iodide, sodium iodide, lithium iodide, potassium bromide, sodium bromide, lithium bromide, and a phenol compound. Preferably, this is carried out by immersion. The concentration of the aqueous solution at this time varies depending on the type of drug used and is not constant. For example, when using a mixed aqueous solution of iodine and potassium iodide,
The appropriate concentration of each is usually about 0.002 to 0.5 mol/. Further, in the case of metacresol, it is usually appropriate to set the concentration to about 0.005 to 0.5 mol/. Although the treatment temperature is not particularly limited, it is usually appropriate to set it at about 5 to 50°C. Further, the processing time also varies and is not constant, but in the above case, it is usually appropriate to set it to about 1 second to 10 hours. If the amide group is not activated, 2
Since coordination of valent copper ions does not occur, the first sulfide
No copper coating is formed. Therefore, during this activation treatment, activation treatment may be performed on any part of the polyamide molding by immersing a part of the polyamide molding in a treatment solution or masking a part of the polyamide molding. The first sulfide layer is applied only to the desired areas.
A copper coating can be easily formed. For example, the cuprous sulfide coating can be easily formed on only one side of the film, or the coating can be easily formed only on the side of the molded body that needs to be made electrically conductive. Incidentally, prior to the activation treatment of the amide group, if necessary, a conventional degreasing treatment may be performed. Next, the activated polyamide molded article is treated with a divalent copper ion solution, and then brought into contact with a sulfur-containing reducing agent. The treatment with a divalent copper ion solution is not particularly limited, but for example, the treatment with a cupric salt such as cupric nitrate, cupric sulfate, cupric acetate, cupric chloride, etc. is usually 0.01~
This is preferably carried out by immersion in an aqueous solution of about 10 mol/preferably 0.1-5 mol/at a temperature of about 5-50° C. for about 1 second to 5 hours, preferably 2 minutes to 1 hour. The contact treatment with a sulfur-containing reducing agent is not particularly limited, but for example, the amount of sulfur-containing reducing agent such as sodium thiosulfate, sodium sulfite, sodium sulfide, potassium thiosulfate, potassium sulfite, potassium sulfide, etc. is usually about 0.01 to 10 mol/preferably 0.1 ~
5 mol/aqueous solution, preferably about 10 to 100℃
This is preferably carried out by immersion at a temperature of 40 to 80°C for about 10 minutes to 1 hour, preferably 1 to 24 hours. The treatment with the divalent copper ion solution and the contact treatment with the sulfur-containing reducing agent may be carried out using separate containers, but the treatment solution after the former treatment is not particularly removed, and the It is more preferable to further add the latter treatment solution to the mixture and perform the latter treatment continuously. These treatments are suitably carried out by stirring or shaking as appropriate. By treatment with a divalent copper ion solution and then contact treatment with a sulfur-containing reducing agent, the divalent copper ion is coordinated to the amide group, and then the ion is reduced to a monovalent one, and at the same time, sulfur is bonded. As a result, a cuprous sulfide coating having metallic luster is formed in close contact with the surface of the polyamide molded article. The thickness of the cuprous sulfide coating depends on the concentration of the cupric salt in the former treatment, but as described above, it is usually about 0.01 to 50 μm. In this way, the conductive polyamide molded article of the present invention can be manufactured and obtained. Effects of the Invention The present invention provides the following remarkable effects. (1) Cuprous sulfide coatings can be formed in close contact with the surfaces of various polyamide moldings in an extremely simple manner, and novel conductive polyamide moldings that have not been previously obtained can be obtained. (2) The adhesion of cuprous sulfide coatings is extremely excellent, and cross-cutting tests usually show 100% adhesion. (3) Since the cuprous sulfide coating uniformly covers the surface of the polyamide molded product, its conductivity is extremely stable. Regarding conductivity itself, uncoated polyamide molded products usually have a conductivity of 10 ¹¹ Ω.
The conductive polyamide molded product of the present invention usually has an electrical resistance of 10 ^cm .
It shows excellent conductivity with a value of Ω・cm or less. (4) Cuprous sulfide coatings also have excellent cold resistance and heat resistance. EXAMPLES Hereinafter, the present invention will be explained in more concrete terms with reference to Examples. Example 1 Polyamide-6 disc-shaped film (thickness:
50 μm, diameter: 7 cm), 2.5 g of iodine
(10 mmol), potassium iodide 3.3 g (20 mmol)
The amide group was activated by immersing it in an iodine solution prepared by dissolving it in 100 ml of distilled water at room temperature for about 20 seconds, followed by washing with running water for about 30 minutes. Cupric sulfate solution 20
ml (0.4 mol/) at room temperature for several minutes, then add 20 ml (0.4 mol/) of sodium thiosulfate solution, leave for a few more minutes at room temperature, heat at 63°C, shake for 3 hours, wash with water and dry. A conductive polyamide film of the present invention was obtained in which a cuprous sulfide coating having a blue-green metallic luster was closely formed on both surfaces of the film. The surface resistivity value of this conductive film was measured using a "4328Δ milli-ohmmeter" manufactured by Heuretsu Card Co., Ltd. using a DC power supply four-point method, and found to be 2.0×10 ² Ω. Further, the adhesion of the cuprous sulfide coating of this conductive film was evaluated by the adhesion rate using the cross-cutting test method described below, and it was found to be 100%, indicating that the adhesion was extremely excellent. 〇Measurement of adhesion rate...After making 11 score lines that reach the film surface in a matrix pattern at 1 mm intervals vertically and horizontally on the conductive surface of the conductive film to be tested,
Attach an adhesive tape of 1.0 to 1.5 cm and a length of 3 to 5 cm ("Mending Tape" manufactured by Nichiban Co., Ltd.), then peel off the tape at once in a direction of 90 to 180 degrees to the film surface to remove the base grain. Out of 100 pieces, the ratio of the number of pieces whose cuprous sulfide coating remained without peeling off was expressed as a percentage. All these operations were performed at room temperature. In addition, when this conductive film was subjected to surface analysis using X-ray photoelectron spectroscopy (ESCA) (using Shimadzu Corporation's ``ESCA750'' and data processing device ``ESCAPAC760''), a peak of cuprous sulfide was found. It was confirmed. Further, the nitrogen peak of the amide group disappears and the peak of the amide carbonyl carbon, especially the subpeak, shifts significantly, so it can be inferred that cuprous sulfide is coordinated on the amide group. The analysis results are shown in Table 1. The unit of numerical values in Table 1 is eV.

[Table] When this conductive film was observed using a scanning electron microscope ("T-100" manufactured by JEOL Ltd.), it was found that a cuprous sulfide coating with a thickness of 0.2 to 0.3 μm was formed in close contact with the film. It turns out that there is. A scanning electron micrograph (magnification: 30,000 times) is shown in FIG. Furthermore, the cold resistance of this conductive film was determined by measuring the adhesion rate after being immersed in liquid nitrogen (-176°C) for 1 hour, and the heat resistance was determined by soaking it in boiling water (100°C) for 1 hour.
By measuring the adhesion rate after soaking for a time,
When I checked each, it was 100% in all cases.
The adhesion rate was found to be excellent in cold resistance and heat resistance. Example 2 A conductive polyamide film of the present invention was obtained in the same manner as in Example 1, except that a disc-shaped polyamide-6 film having a thickness of 150 μm was used as the raw material. The surface resistivity value of this conductive film was measured in the same manner as in Example 1 and was found to be 6.4×10 ² Ω. Further, the adhesion rate was examined by measuring the adhesion rate and found it to be 100%. Furthermore, this conductive film was observed using a scanning electron microscope in the same manner as in Example 1. Scanning electron micrographs are shown in Figures 2-4. Figure 2 (magnification
30,000 times) shows the surface of untreated polyamide-6 film. Figure 3 (30,000x magnification) shows the surface of the conductive film obtained in this example.
It can be seen that the surface is almost as smooth as in the case of FIG. 2, and that the cuprous sulfide coating is uniformly and tightly formed. Figure 4 (magnification: 4200x) shows the cross section of the conductive film obtained in this example, with a thickness of approximately
It can be seen that the 5 μm cuprous sulfide coating is uniformly and tightly formed. Example 3 A conductive polyamide film of the present invention was obtained in the same manner as in Example 1, except that a disc-shaped polyamide-6 film having a thickness of 5 μm was used as the raw material. The surface resistivity value of this conductive film was measured using a "TR6843 multimeter" manufactured by Takeda Riken Kogyo Co., Ltd. using a two-point DC power source method.
It was 3.2×10 ³ Ω. Example 4 A disc-shaped film of polyamide-6 having a thickness of 150 μm was used as the raw material, and the amide groups were activated by immersing it in a 0.05 mol/methacresol aqueous solution for 4 hours. A conductive polyamide film of the present invention was obtained in the same manner as in Example 1. The surface resistivity value of this conductive film was measured in the same manner as in Example 1 and was found to be 6.5×10 ² Ω. Further, the adhesion rate was examined by measuring the adhesion rate and found it to be 100%. Examples 5 to 7 Conductive polyamide films of the present invention were obtained in the same manner as in Example 1, except that the polyamide disc films shown in Table 2 were used as raw material polyamide disc films. The surface resistivity value and adhesion rate measured in the same manner as in Example 1 are also listed in Table 2.

[Table] Examples 8 to 9 Circular woven fabrics (diameter: 7 cm) of polyamide-6 and polyamide-6,6 were immersed in the iodine solution described in Example 1 for about 20 seconds at room temperature to activate the amide groups. was applied, rinsed with running water for about 30 minutes, and then air-dried. Soak in 20 ml (0.4 mol/) of cupric nitrate solution for several minutes at room temperature, then soak in sodium thiosulfate solution.
20 ml (0.4 mol/) was added, and the mixture was left at room temperature for several minutes, heated at 63°C, shaken for 3 hours, washed with water, and dried to obtain a conductive polyamide woven fabric of the present invention having a blue metallic luster. Table 3 shows the surface resistivity values measured in the same manner as in Example 1.

[Table] Example 10 Polyamide-6 dissolved in formic acid was cast on a polyethylene (PE) porous film to form a thin film. Using this film, a cuprous sulfide coating was closely formed on the surface of a polyamide-6 thin film supported on a PE porous film in the same manner as in Example 1 to obtain a conductive polyamide-polyethylene multilayer film of the present invention. The surface resistivity value of this conductive film was measured in the same manner as in Example 3 and was found to be 1.7×10 ⁴ Ω. Comparative Example 1 Copper sulfide treatment was performed in the following order (1) to (3). (1) Polyamide-6 disc film (thickness:
50μm, diameter: 7cm) in hydrochloric acid aqueous solution (3.8N)
for 5 minutes at room temperature. (2) Remove the film, wash it with water, dry it at 50℃ for 30 minutes, and add 10% by weight of 1,6-hexanediamine.
It was immersed in an aqueous solution at 90°C for 10 minutes. The film was taken out, washed with water, and then dried at 100°C for 1 hour. (3) This film was immersed in an aqueous solution containing copper sulfate (0.25 mol/) and sodium thiosulfate (0.25 mol/), the temperature was gradually raised from room temperature to 94°C, and the film was treated at 94°C for 10 minutes. 100 more after washing with water
It was dried at ℃ for 1 hour. The obtained film was visually observed and tested for adhesion. After the film is treated with hydrochloric acid in (1), its surface color changes to
It was observed that the color changed from milky white to white and the surface was considerably deteriorated. After the copper sulfide treatment (3), uneven adhesion of copper sulfide to the film was observed. In addition, the adhesion of the copper sulfide coating was examined by applying the adhesive tape described in Example 1 and peeling it off. As a result, the copper sulfide coating was easily peeled off, and the adhesion of the copper sulfide coating to the film was extremely weak. It has been found. Comparative Example 2 Polyamide-6 disc film (thickness:
50 μm, diameter: 7 cm) in Example 1, except that the amide group activation treatment using an iodine solution was not performed.
Processed in the same way. That is, immerse in 20 ml (0.4 mol/) of cupric nitrate solution for several minutes at room temperature, then soak in sodium thiosulfate solution.
20 ml (0.4 mol/) was added, and the mixture was left at room temperature for several minutes, heated at 63°C, and shaken for 3 hours. As a result of washing the obtained film with water, the copper sulfide attached to the surface came off, and when the obtained film was rubbed with a finger, the copper sulfide came off easily.
It was found that the copper sulfide did not adhere to the film and that the cuprous sulfide coating was not formed in close contact with the film.

[Brief explanation of the drawing]

FIG. 1 is a scanning electron micrograph of the conductive polyamide film of the present invention obtained in Example 1 (magnification
30000 times). Figure 2 is a scanning electron micrograph of an untreated polyamide-6 film (magnification
30000 times). Figures 3 and 4 are scanning electron micrographs of the conductive polyamide film of the present invention obtained in Example 2 (magnifications of 30,000x in Figure 3;
Figure shows 4200x).

Claims (1)

[Scope of Claims] 1. A conductive material characterized in that a cuprous sulfide coating is closely formed on the surface of a polyamide molded product through coordination bonds between the amide groups of the polyamide molded product and cuprous sulfide. polyamide molded product. 2. The amide group was activated using at least one selected from iodine, bromine, potassium iodide, sodium iodide, lithium iodide, potassium bromide, sodium bromide, lithium bromide, and a phenol compound. The polyamide molded product is treated with a divalent copper ion solution, and then brought into contact with a sulfur-containing reducing agent to reduce the copper ions to monovalent ones, so that the amide groups and sulfide groups of the polyamide molded product are coated on the surface of the polyamide molded product. 1. A method for producing a conductive polyamide molded article, characterized in that a cuprous sulfide coating is formed in close contact with cuprous sulfide by coordination bonding with cuprous sulfide.