JPH0440839B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a molded container having conductive and antistatic properties, and is suitable for storing electronic components such as ICs that are prone to electrostatic damage. As electronic equipment products become more sophisticated, precise, and dense, many ICs, LSIs, VLSIs, etc. are being incorporated into them. However, these materials can be damaged even by minute electrostatic discharges or charges, and are susceptible to so-called static electricity damage, which impairs functionality. Conventionally, when these ICs and chip parts devices are handled through various processes such as storage, sorting, transportation, and installation, they are made of vinyl chloride, polystyrene, polycarbonate, polypropylene, polyethylene, polyamide, polyester,
A plastically moldable thermoplastic resin sheet made of ABS resin or the like was molded into a predetermined shape depending on the contents and used as a container. This housed the aforementioned IC parts, which have a surface resistivity of 10 ¹³ Ω.
As described above, it was extremely easy to be charged, and the charged electric charge was difficult to escape, adversely affecting the electronic components contained therein and easily causing electrostatic damage. Therefore, in order to prevent this accident, it was common to store these items and then cover the container with metal foil such as aluminum foil to prevent static electricity. However, this required double work, and frictional electrification due to sliding during transportation could occur between the bottom of the container and the contents in contact, so it was not a perfect solution. In addition, attempts have been made to provide the container itself with antistatic properties. That is, various types of surfactants consisting of cationic, anionic, nonionic, and amphoteric surfactants having antistatic properties are kneaded into the various thermoplastic resins mentioned above, melted and formed into a film-formed meat, which is then made into a container. In this case, this antistatic agent had drawbacks such as thermal decomposition, falling off the surface, and reduced effectiveness under low humidity conditions. Furthermore, antistatic agents made of these surfactants have a limit of reducing the surface resistivity of thermoplastic resins to about 10 ¹⁰ Ω, and are unsatisfactory in terms of performance when applied to containers for electronic components. Ta. Carbon black powder or carbon fiber, which has excellent conductivity, is also melt-kneaded in the same manner as above, but in this case, in order to obtain something with excellent conductivity, as the amount added increases, the processability deteriorates. The original physical properties of the resin, such as moldability, deteriorate significantly,
In practice, various problems arose. The present invention was obtained as a result of studies to solve the various problems described above, and is made by coating and forming a conductive composition layer on the surface of a plastically moldable thermoplastic resin sheet. It is molded into a desired container shape and is used for storing electronic components such as ICs. For electronic components such as ICs that are susceptible to static electricity damage, the surface resistance of these packaging containers should be increased to 10 ⁶
It is said that static electricity damage can be prevented if the resistance is set to Ω or less. As shown in FIG. 1, the present invention uses polyester,
A conductive paint 1 containing acetylene black added to a resin solution of polyamide, acrylic, vinyl acetate, cyclized rubber, etc. is applied to both sides of a plastically moldable thermoplastic sheet 2 by a known method. As shown in Fig. 2, it is a conductive and antistatic molded container formed by plastic molding. The surface resistivity of the molded container of the present invention is 10 ⁶ Ω or less, which is sufficient to accommodate electronic components and the like. The thermoplastic sheet 2 of the present invention is made of polyvinyl chloride, polystyrene, polycarbonate, polypropylene, polyethylene, and ABS resin, and the conductive paint 2 is selected taking into account its adhesiveness with the thermoplastic sheet 1. The conductive paint must be applied to both sides of the molded container, and one side must be in contact with the contents. Further, in addition to forming the coated surface on the entire surface, it may be formed in a continuous pattern such as a lattice shape or a mesh shape in consideration of the design and the like. Note that the continuous pattern is necessary partly because no potential difference occurs. In addition, acetylene carbon black is useful as a conductive material added to conductive paint in terms of handling, and when added in an amount of 10 to 40% by weight, the surface resistivity increases.
10 ⁶ Ω or less. If the amount added is less than 10% by weight, the surface resistivity may exceed 10 ⁶ Ω, and if it exceeds 40% by weight, there will be problems in the applicability as a paint and the moldability after application, which is not preferable. Furthermore, a protective layer made of a thermoplastic resin may be provided on the conductive paint to protect the paint within a range that does not impair the predetermined surface resistance. Since the container of the present invention is a container formed of a sheet in which conductive paint having a surface resistivity of 10 ⁶ Ω or less is continuously provided on both sides, static electricity is not generated on the side where electronic components are stored and also on the outside. There is no charge, and static electricity does not occur even when stacked during transportation or storage. In addition, when applying conductive paint after forming a sheet, it is difficult to apply it continuously, but in the present invention, the surface resistivity is applied on both sides of the sheet in advance.
Since it was molded with conductive paint of 10 ⁶ Ω or less,
Containers with constant surface resistivity are easily obtained. Next, examples of the present invention will be described. [Example] A conductive paint having the following composition was applied to both sides of a plastically moldable hard vinyl chloride resin sheet (0.2〓thickness) to a gravure plate depth of 90μ, and the coating amount was 4.5g/m ²
A molded container having a shape as shown in FIG. 2 was obtained by vacuum forming a molded sheet of (solid amount) at a molding temperature of 120°C. (Conductive paint) Acetylene black (Denka black 50% pressed product) 100 parts by weight (Denka Kagaku Kogyo Co., Ltd.) Unsaturated polyester resin (Vylon #200) 400〃 (Toyobo Co., Ltd.) Homogenol L-18 (Surface active (Kao Atlas Co., Ltd.) Toluene (solvent) 1000 Methyl ethyl ketone (solvent) 1000 Electrical properties such as surface resistivity, charge level and charge decay time of the molded container of the present invention are shown in the table below. It was like that.

【table】

[Table] Since the container of the present invention has a surface resistivity of 10 ⁶ Ω or less on both sides, static electricity does not build up on the side where electronic components such as ICs are stored, and on the outside as well. Because it is a configuration set up specifically for
It is an excellent protective container for storing electronic components such as ICs, and does not suffer from deterioration in functionality due to static electricity during transportation and storage.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a sheet used in the molded container of the present invention, and FIG. 2 is an explanatory diagram showing one embodiment of the molded container of the present invention. 1... Conductive paint, 2... Thermoplastic sheet.

Claims (1)

[Claims] 1. A conductive material made of acetylene carbon black is coated on both sides of a thermoplastic sheet that can be plastically molded.
Conductive material made by plastically molding a molded sheet continuously coated with a conductive paint with a surface resistivity of 10 ⁶ Ω or less,
Antistatic container.