JPH0575287A - Manufacture of plastic shield plate - Google Patents

Abstract

PURPOSE:To obtain a plastic shield plate where a flame-sprayed zinc particle cannot be released as one means against spurious noise by shielding an enclosure by performing sandblast onto a plastic plate with an alumina material and then performing flame-spraying of zinc. CONSTITUTION:A sandblast treatment with an alumina material is performed to one side of a plastic plate 1. An air pressure, a spray time, and an alumina particle diameter are preset so that a surface roughness of the plastic plate is 15-20 microns larger than a particle diameter of zinc at the time of flame- spraying of zinc. Then, flame-spraying of zinc is performed onto a blast surface 5 of the plastic plate subjected to sandblast treatment. A large current is made to reflow between the two zinc wires and a high compressed air is jetted to the melted material from a distance 30-50cm away from a target. The plastic surface 5 after sandblasting is roughened to 15-20 microns, thus enabling a zinc particle 4 to be adhered onto surface recessed and projecting parts and obtaining an improved adhesion property.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic shield plate of a plastic shield casing used to shield unnecessary radio waves, and relates to a surface treatment of a plastic material when zinc spraying is used.

[0002]

2. Description of the Related Art Conventionally, in zinc spraying on plastic materials, in order to obtain adhesion of zinc particles to the plastic material, Rabi coating is applied to the plastic material as a base treatment so that the adhesion of the zinc particles to the plastic material is provided. Was there.

FIG. 2 shows a configuration diagram of a conventional plastic shield plate. In FIG. 2, 1 is a plastic material, 2 is a rabbi coating film coated on the plastic material 1, 3 is beads contained in the rabbi coating, and 4 is zinc particles sprayed on the rabbi coating film. As shown in FIG. 2, plastic material 1
On the upper side, the coating film has a roughness of about 5 to 6 microns due to the beads 3 contained in the rabbi paint, and the zinc particles 4 adhere to and are in close contact with the irregularities on the surface of the rabbi coating film 2.

[0004]

However, in the above-mentioned conventional method, since the particle size of the zinc particles is larger than the unevenness of the surface of the Rabi coating film, the adhesiveness is not sufficient and peeling off occurs in the tape peeling test by cross-cutting. There was a problem with reliability.

The present invention is intended to solve the above problems.

[0006]

In order to solve the above problems, the present invention is to subject a plastic plate to sandblasting with an alumina material.

[0007]

According to the present invention, the adhesion of zinc particles is improved by the above-mentioned manufacturing method, problems in tape peeling tests can be eliminated, and reliability can be dramatically improved.

[0008]

EXAMPLE A process for manufacturing a plastic shield plate according to the present invention will be described.

First, one side of a plastic plate is sandblasted with an alumina material. In this method, alumina particles are blown onto a plastic plate which is an object by high pressure air. The air pressure, spraying time, distance, and alumina particle size are 15 to 20 μm so that the adhesion of zinc spraying can be obtained, that is, the surface roughness of the plastic plate is larger than the particle size of zinc when zinc is sprayed. To preset. The reason why the alumina material is used for this sandblast treatment is that the optimum diameter for obtaining an arbitrary surface roughness can be selected because the type of particle diameter is subdivided.

In this embodiment, in the case of polystyrene plastic, air pressure: 4-4.5 kg / cm 2, distance: 30
~ 40 cm, Alumina particle size: # 16, Spraying time: Arbitrary (depending on area), sandblasting is performed.

Next, zinc blasting is applied to the blast surface of the sandblasted plastic plate. This is a method in which a large current is passed between two zinc wires and the material is melted and blown onto the object from a distance of 30 to 40 cm by high-pressure air. Air pressure, current, and spray distance are set so that the particle size of zinc adhering to the plastic plate is smaller than the roughness of the blast surface of the plastic plate, which is 15 to 20 microns, so that the zinc particles are embedded in the uneven parts of the plastic blast surface. Set in advance. The spraying time is 100 to 20 so that a good shielding effect can be obtained.
It is preset to be 0 micron.

In this embodiment, the air pressure is 7.5 kg / cm2.
, Current: 100 amperes, distance: 30-40 cm, spraying time: arbitrary (depending on area), zinc spraying is performed.

FIG. 1 is a block diagram of the plastic shield plate manufactured by the manufacturing method of the present invention. Reference numeral 1 is a plastic material, 5 is a plastic surface after sandblasting, and 4 is zinc particles welded to the plastic surface after sandblasting.

As shown in FIG. 1, since the plastic surface 5 after sandblasting is roughened to 15 to 20 μm, the zinc particles 4 adhere to the irregularities on the surface and good adhesion is obtained.

[0015]

As described above, according to the present invention, the sprayed zinc particles are peeled off as a method for preventing unnecessary radiation by the housing shield by performing zinc spraying after sandblasting a plastic plate with an alumina material. No plastic shield plate can be provided.

[Brief description of drawings]

FIG. 1 is a structural diagram of a plastic shield plate of the present invention.

FIG. 2 is a block diagram of a conventional plastic shield plate.

[Explanation of symbols]

 1 plastic material 2 Rabi coating film 3 beads in Rabi paint 4 zinc particles 5 plastic surface after sandblasting

Claims (1)

[Claims] 1. A method for producing a plastic shield plate, which comprises subjecting a plastic plate to sandblasting with an alumina material and then performing zinc spraying.