JPS6019607B2 - Highly conductive surface resin molded product - Google Patents

Description

[Detailed description of the invention] The present invention relates to a resin molded article with a highly conductive surface.

Accordingly, methods for imparting conductivity to non-conductive synthetic resin molded products include '1) mixing metal powder such as silver powder, knotweed powder, aluminum powder, or nickel powder, '2] mixing epoxy resin with Methods that have been used include mixing graphite, and mixing epoxy resin with carbonyl nickel powder and curing it while applying a magnetic field. However, in the method of mixing metal powder of m, a considerable amount must be mixed in order to achieve a resistivity in the range of 1 to 10-50, which is generally referred to as conductive plastic. There is a need,
The price of metal powder is also high, resulting in increased costs and decreased physical properties. In addition, in the method (2) of mixing carbon black and graphite (carbon black and graphite are cheaper than the metal powder in 11), the cost of the product itself can be kept low.

However, the amount used is still large, and the physical properties are much worse than those mixed with metal powder. Even with the method of making molded products by mixing epoxy resin with nickel powder, as described in the previous section, conductivity is insufficient unless a large amount of magnetic powder is used. In addition, with conventional methods, it is necessary to uniformly mix a substance that imparts conductivity into the molded product in order to lower the electrical resistance only on the surface, and it is necessary to make conductivity even inside the resin of the molded product, which does not require any conductivity. Since the applied substance is mixed in the same proportion as the surface, the physical properties of the molded product are significantly reduced.

As a result of repeated research aimed at improving the conventional molded products as described above, the inventors of the present invention have found that the resin surface of the molded product collects a large amount of conductive material to lower the electrical resistance, and the inside of the resin is made of a conductive monster. By reducing the mixing ratio and maintaining physical properties, we succeeded in providing a molded product that has both lower surface electrical resistance and excellent physical properties that could not be obtained with conventional molded products.

That is, the present invention provides a molded article formed from a resin composition containing powder obtained by coating magnetic powder with conductive powder, in which the synthetic resin composition is in a molten state or in an unmolten state. This resin molded article has a high surface conductivity and is characterized by being placed under the influence of a strong magnetic field perpendicular to the surface of the molded article and then under the influence of a magnetic field parallel to the surface image of the molded article in the hardened state.

The magnetic powder referred to in the present invention is typically triiron tetroxide (Fe304) or iron black containing it as a main component.

However, as long as the powder is coated with conductive powder and has magnetism, the idea of the present invention will not be ignored. Nor do they have to be used alone;
They can be used in combination as long as they do not significantly reduce the effect of the invention.

Examples of the electrically conductive powder in the present invention include carbon black and graphite.

Examples of synthetic resins include thermoplastic resins such as polyvinyl chloride, polyethylene, polyethylene oxide, polypropylene, polystyrene, high impact polystyrene, ABS, and polymethyl methacrylate, thermosetting resins such as urea formaldehyde, phenol formaldehyde, and epoxy resins. Examples include polyurethane. The strength of the magnetic field used in the present invention is preferably strong when applying a magnetic field perpendicular to the surface of the molded product. When the viscosity is low, the present invention can be achieved with a viscosity of about 5000 Gauss.

Also, when applying a magnetic field parallel to the surface of the molded product, the strength is 1
000 Gauss or more is desirable. Good results cannot be obtained below 1000 Gauss. However, it must not be stronger than the magnetic field applied perpendicular to the surface of the molded product. Examples are shown below, but the present invention is not limited to these Examples in any way.

Note that the molded article of the present invention may be mixed with commonly used stabilizers, anti-aging agents, and other additives.

Example 1 Ferrous sulfate, ferric sulfate, and carbon black (average particle size 0.1 mm, oil absorption 30 cc Caustic soda was gradually added to the mixture while pouring the mixed solution of 1/100 min.

Observation of the obtained black coprecipitate revealed that iron tetraoxide and trioxide were completely coated with carbon black, and had sufficient coating strength.

4 parts by weight of the obtained epoxy precipitate and 9 parts by weight of epoxy were mixed, a curing agent was added, and the mixture was heated under the influence of a magnetic field of 5000 Gauss.
It was then cured for 50 minutes at 60 pm under the influence of a 1500 Gauss magnetic field parallel to the surface to produce a flat plate with a thickness of 1.0 arc.

A cube with a side length of 1.0 skin was created from the obtained flat plate.

A conductive material (silver paint) was applied to mutually parallel surfaces perpendicular to a 1500 gauss magnetic field on the sides of the cube, and after drying, parallel lines were drawn from above using a cutter knife at intervals of one rib. Parallel lines perfectly separated the conductive material by one skin distance. It's a shame to number them from the top. 1~M. It was set as 10. The electrical resistance values of the opposing numbers were measured and used as examples.

A coprecipitate and epoxy were mixed with the same composition as in the example, a curing agent was added, and the mixture was cured at 60° C. for 1 hour under the influence of a 5000 Gauss magnetic field to obtain a flat plate with a thickness of 1.0 cm.

A cube with a side of 1.0 arc is made from the obtained flat plate, and conductive paint (silver paint) is applied to two opposite sides parallel to the magnetic field, and after drying, the cube is made parallel to the lines of magnetic force with a spacing of 1 rib so that they are perpendicular to the lines of magnetic force. I drew a line. The silver paint was completely independent at one rib interval. Ships numbered from the top. 1
~shame. 10, and the electrical resistance value was measured in the same manner as in the example.
This was designated as Comparative Example 1. Comparative Example 2 was obtained by measuring the electrical resistance value of the same machine as Comparative Example 1 using the same method as Comparative Example 1 except that the magnetic field was set to 1500 Gauss.

The results are shown in Table 1.

Table 1 Example 2 Using the black coprecipitate obtained in Example 1, polyethylene 9
4 parts by weight and 6 parts by weight of black coprecipitate were mixed and heated at a temperature of 160 qo for 4 minutes under the influence of a magnetic field of 8000 gauss.Then, the magnetic field was rotated at 900 rpm and 2 minutes under the influence of a magnetic field of 3000 gauss to obtain a thickness of 1. A flat plate with an arc of .0 was molded.

The obtained flat plate was treated in the same manner as in Example 1, and the upper and lower parts were separated by 1
I divided it into equal parts and measured the electrical resistance of each. Next, Comparative Example 3 was prepared in the same manner as in Example 2 except that the magnetic field was set to only 8000 Gauss.

Comparative Example 3, except that the magnetic field was set to only 3000 Gauss.
Comparative example 4 was prepared in the same manner as above.

The results are shown in Table 2.

Table 2

Claims (1)

[Claims] 1 In a molded article made from a synthetic resin composition containing powder obtained by coating magnetic powder with conductive powder, the synthetic resin composition may be in a molten or uncured state. 1. A resin molded article with a high surface conductivity obtained by subjecting the article to a strong magnetic field perpendicular to the surface of the molded article and then to a magnetic field parallel to the surface of the molded article.