JPH0470966B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a plastic molded product in which a multilayer coating consisting of a conductive coating and an aesthetic coating and/or a protective coating formed thereon is formed on the surface of a plastic molded article. Regarding the molding method.

More specifically, the present invention relates to a method for obtaining a plastic molded body having the purpose of shielding electromagnetic waves, preventing static electricity, etc.

(Prior art) In recent years, it has become clear that electromagnetic waves and static electricity are the cause of malfunctions in electronic devices that use semiconductor devices, and in Western countries, malfunctions are caused by electromagnetic waves and static electricity.
Regulations for electronic devices with built-in IC and LSI elements are beginning to be enacted into law, and the electronic device industry is urged to take countermeasures.

Currently, one of the methods to shield these sources of interference electromagnetic waves is to knead conductive powder into plastic and then mold it, giving the plastic molded body itself a conductive function (for example, Japanese Patent Publication No. 35-9643 )It has been known. however,
Although this method has the advantage of being easy to work with, it requires the inclusion of a large amount of conductive powder in order to obtain a good electrical conductor, which results in a decrease in the physical strength of the plastic after molding, an increase in weight, and problems with molding. It has not been put into practical use much because of various other drawbacks such as the above problems.

Another known shielding method is to apply a solvent-soluble conductive paint to the inner surface of an electronic device housing with a brush or spray.
In this method, it is necessary to take measures against shape damage and discoloration caused by organic solvents contained in conductive paints, as well as undercoat measures to improve paint film adhesion strength and prevent paint film peeling. There were problems such as odor caused by solvent volatilization, adverse effects on the human body, and danger of fire.

Recently, a method has been developed in which a solvent-soluble conductive paint is applied with a brush or a spray gun into a mold for electronic device housings, and then the plastic is molded within the mold to integrate the plastic molded body and the conductive film. has also been proposed (for example, Special Publication No. 48-25061).
According to this method, a grease-like composition is applied inside a mold, a conductive powder such as graphite is sprayed onto it, and then a liquid synthetic resin is injected and hardened to make predetermined areas conductive. A method has been proposed for obtaining an insulating molded body with a high temperature. However, this method has the basic problem that the conductive powder has weak adhesion at points other than the points of contact with the grease-like composition, so careful attention is required when injecting the resin, and in addition, the injection speed is also limited. There were problems with the work, such as the fact that it was extremely slow.

Therefore, this method cannot be applied to high-speed molding methods such as injection molding methods.

In addition, the above-mentioned known example also describes a method of using a synthetic resin adhesive before resin injection in order to strengthen the adhesion of the conductive powder, but if this method is adopted, the aforementioned solvent can be removed. None of the problems associated with applying a melt-molded conductive paint after molding have been solved.

Generally, as a means to solve the above-mentioned problems of solvent-soluble paints, for example, the use of powder paints that do not contain any solvent can be considered.

In fact, in the field of molding, powder coatings containing a small amount of ordinary color pigments are heated and applied to the inner surface of a pressure molding mold in a fluidized bed or by spraying, and then compression molded using SMC or BMC.
Methods of forming a protective or colored film on the FRP surface are known (for example, Japanese Patent Publication No. 58-44459,
JP-A-57-181823, JP-A-58-124610).

However, even with these methods, there are problems such as powder scattering, adhesion to the outside of the mold, and uneven film thickness.

On the other hand, since conductive coatings are conductive, if they are exposed inside an electronic device housing, there is a high risk of electric shock or leakage due to contact with internal devices that carry current. This is one of the problems.

Furthermore, since the types of conductive fine powders used in conductive paints are limited, there are also problems in that the number of colors is small and that they cannot be used for aesthetic purposes.

(Problems to be solved by the invention) The present invention solves safety and hygiene problems caused by organic solvent volatilization, and problems such as scattering of powder paint, adhesion to the outside of the mold, and uneven film thickness. By solving this problem, a powdered resin composition containing a high concentration of conductive fine powder can be efficiently and uniformly attached to the plastic surface.
The object of the present invention is to provide a method for molding a plastic molded article having electrical conductivity and a surface resistance value of about 10 ² ohms/□ or less.

Furthermore, the present invention provides a multilayer coating consisting of a coating film having a conductive function, a coating film having a function of preventing electric shock and leakage accidents, an aesthetic and/or protective function of the conductive coating film, and, if necessary, an antistatic function. It is an object of the present invention to provide a plastic molding method that forms a film.

(Means for Solving the Problems) That is, the present invention first applies an insulating powdered resin composition into a mold by electrostatic coating, and then coats the conductive powdered resin composition thereon by electrostatic coating. The present invention relates to a plastic molding method in which after painting, the plastic is molded and a multilayer film consisting of a conductive film and an insulating film is anchored and adhered to the surface of the plastic molded body.

(Specific Description of the Invention) The insulating powdery resin composition used in the method of the present invention is a powdery thermosetting or thermoplastic resin composition usually used for powder coatings (coloring pigments described below). (compositions containing or not containing etc.). In the present invention, insulation refers to a surface resistance value of about 10 ⁵ ohms/□ or more.

Examples of the thermosetting resin include acrylic resin, polyester resin, epoxy resin, alkyd resin,
Urethane resin, epoxy modified polyester resin,
An example is acrylic modified polyester resin. In particular, acrylic resins, polyester resins, and epoxy resins are preferred from the viewpoint of storage stability and conductivity of the coating film.

Various types of thermosetting resins can be used, such as a self-curing type and a curing agent (crosslinking agent) curing type.

Examples of the curing agent for the thermosetting resin include dicyandiamide, acid anhydride, imidazole derivative, aromatic diamine, boron trifluoride amine complex compound, hydrazide, decamethylene dicarboxylic acid, blocked isocyanate compound, amino resin, etc.
Those normally used for thermosetting powder coatings, powder molding, etc. can be used.

Further, as the thermoplastic resin, known ones such as polyester resin, acrylic resin, epoxy resin, polyethylene resin, polypropylene resin, styrene polymer, vinyl chloride polymer, polyamide resin, butyral resin, cellulose resin, and petroleum resin are used. Can be mentioned.

The thermosetting resin and the thermoplastic resin can be used individually or as a mixture, or if necessary, the thermosetting resin and the thermoplastic resin can be used in combination.

In the present invention, the resin component used in the powdered resin composition has a softening point of 40 to 160°C and a melting point of 60 to 160°C.
180℃, preferably softening point 60~130℃, melting point 70~
The temperature is about 160℃.

The softening point was measured by Kofler's method, and the melting point was measured by Durran's method.

In the insulating powder resin composition, when using a colored pigment, examples of the colored pigment include inorganic pigments such as titanium oxide, zinc white, lead white, carbon black, yellow lead, iron oxide, Bengara, ultramarine, and chromium oxide. Pigments and organic pigments such as azo-based, vat-dye-based, quinacridone-based, phthalocyanine-based, and nitroso-based pigments, and other coloring pigments or dyes that are generally used in powder coatings can all be used. These may be used alone or as a mixture of two or more.

Furthermore, when the insulating powder resin composition of the present invention is used for antistatic purposes (surface resistance value of 10 ⁵ ohms/□ or more), conductive materials such as SnO ₂ , In ₂ O ₃ , Sb ₂ O ₃ etc. metal oxide, metal doped ZnO, In ₂ O ₃ or SnO _2
etc. , amorphous carbon powder such as graphite carbon and acetylene black, etc.
Alternatively, a small amount of a conductive fine powder, which will be described later, can be used alone or in a mixture, or mixed with the coloring pigment or paint.

All of these will be referred to as colored pigments etc. below.

The coloring pigment etc. is preferably 80% by weight or less, more preferably 0.5% by weight in the insulating powder resin composition.
It contains at least % by weight.

In the present invention, when the insulating powder resin composition is used for beauty purposes, the coloring pigment, etc. is required to be present in the composition in an amount of 0.5% by weight or more;
If it is used in excess of this amount, it becomes difficult to obtain a uniform coating, which is not preferable.

In addition, in the case where the above-mentioned colored pigments etc. are used together as an insulating powdery resin composition in the present invention, the insulating powdery resin composition refers to a composition in which all the colored pigments etc. are included in each individual resin powder. This means a mixture of resin powder containing most of the colored pigment, etc., and a small amount of the colored pigment, etc. (however, the total amount of the colored pigment, etc. is within the above range).

In addition to the above-mentioned components, the powdered resin composition may contain an anti-sag agent, a curing accelerator, an antioxidant,
It is also possible to add and mix components such as extender pigments that are generally used for powder coatings and powder molding.

The insulating powder resin composition used in the method of the present invention can be obtained by a known powder coating manufacturing method.

For example, a mechanical pulverization method in which the resin and other coloring pigments, curing agents, additives, etc. are heated and melted and mixed, and then cooled, crushed, and sieved; A dry spray method or the like can be applied in which the curing agent, additives, etc. are dispersed in a solvent and then the resulting dispersion is sprayed into heated air.

Therefore, when obtaining a composition containing color pigments etc. at a higher concentration, when using a resin with a low melting point, or when considering prevention of agglomeration of a powdered resin composition, the following wet granulation method is used. A manufacturing method using a method is preferred.

For example, water-soluble solvents such as alcohols, ethylene glycol derivatives, diethylene glycol derivatives, esters, and ketones (preferably 20
A liquid composition obtained by dissolving the resin in a solution (having a solubility in water of 10 to 30% by weight at ℃), and then mixing the resin and, if necessary, a coloring pigment, etc., other curing agents, additives, etc. (hereinafter referred to as dispersion)
is emulsified and dispersed in an amount of water (approximately 3 to 40 times the amount of the dispersion) that dissolves all the water-soluble solvents contained in the dispersion. Emulsification is carried out by dropping, pouring, or spraying the dispersion into water under vigorous stirring, or by mixing water and the dispersion using a line mixer.

The above stirring or mixing with a line mixer is
This process is continued until the solvent in the emulsified fine particles migrates into the water and particles are formed.

In this way, the solvent in the emulsion fine particles is extracted into water, and resin particles are obtained.

The resin particles are separated from the water-solvent mixture by filtration or centrifugation, and if necessary, water washing and separation are repeated a necessary number of times to obtain resin particles in the form of a slurry or a water-containing cake. In other words, the insulating powder of the present invention is prepared by pulverizing the resin particles using a ball mill, pot mill, sand mill, etc., if necessary, drying them, preferably by freeze-drying, vacuum drying, etc., to prevent the resin particles from agglomerating, and then sieving if necessary. A resin composition is obtained. Such a manufacturing method is described, for example, in Japanese Patent Application Laid-open No. 48-52851, Japanese Patent Publication No. 54-5832, and Japanese Patent Publication No. 54-54.
-26250, 54-31492, 56-5796, 56
It is detailed in the -29890 publication.

Furthermore, the particle size range of the insulating powder resin composition used in the method of the present invention is about 0.5 to 100 microns, preferably about 1 to 50 microns.

On the other hand, the conductive powdery resin composition used in the method of the present invention is a powdery resin composition containing conductive fine powder.

The conductive fine powder is a metal powder or alloy powder such as gold, platinum, palladium, silver, copper, or nickel; or an inorganic powder or plastic powder that is an electrically poor conductor such as nickel-coated mica powder. It is a fine powder with good electrical conductivity, such as one coated with a metal of good conductivity, and has a particle size range of 0.5 to 100 μm, preferably about 1 to 50 μm. These powders can be used alone or in combination of two or more.

Dendritic metal fine powder is particularly effective for the purpose of the present invention, that is, to obtain a film with good conductivity and excellent adhesion.

The conductive fine powder is preferably 70 to 95% by weight, more preferably 75% by weight in the conductive powder resin composition.
It is contained in the range of ~90% by weight.

In the present invention, the conductive powder resin composition refers to a composition in which all conductive fine powders are encapsulated in individual resin powders. Note that it may contain a mixture of resin powder containing most of the conductive fine powder and a small amount of the conductive fine powder (however, the total amount of the conductive fine powder is within the above range). In either case, it is a matter of course that the electrical resistance in the powder state must be high enough to allow electrostatic coating.

If the amount of conductive fine powder in the conductive powder resin composition is less than 70% by weight, it will not be possible to form a good conductive film on the surface of the plastic molded object, whereas if it exceeds 95% by weight. In some cases, it becomes difficult to perform electrostatic coating efficiently, so both are not very preferable.

As the resin as a color vehicle used in the conductive powder resin composition of the present invention, any thermosetting or thermoplastic resin similar to that used in the insulating powder resin composition can be used without any problem. I can do it.

Further, as a method for manufacturing the conductive powdery resin composition, the same method as the method for obtaining the insulating powdery resin composition can be applied. In particular, when obtaining a resin composition containing a high concentration of conductive fine powder, when maintaining the shape of the conductive fine powder, and preventing agglomeration of the conductive powder resin composition, etc., the wet granulation method is A manufacturing method using a method is preferred.

The softening point and melting point of the resin used in the conductive powder resin composition, as well as the particle size of the resin composition, are preferably within the same range as in the case of the insulating powder resin composition.

On the other hand, there are no particular restrictions on the molding method to which the method of the present invention can be applied, and commonly used molding methods such as compression molding, transfer molding, lamination molding, and injection molding (reaxyan and liquid injection molding) (including yon molding method), blow molding method, vacuum molding method, etc.

Plastic materials used in these molding methods include unsaturated polyester resins, phenolic resins, epoxy resins, urea and melamine resins, styrene resins, acrylic resins, vinyl resins, polyethylene resins, silicone resins, and ABS.
Thermosetting or thermoplastic resins commonly used for molding, such as resins, nylon resins, polyacetal resins, polycarbonate resins, polyphenylene oxide resins, polypropylene resins, etc., and reinforcing fibers, fillers, Resin compositions kneaded with curing agents, stabilizers, colorants, thickeners, mold release agents, foaming agents, flame retardants, etc., as well as sheet molding compounds (SMC), bulk molding compounds (BMC), etc. Available for use.

Next, the molding method of the present invention will be explained.

First, the insulating powder resin composition obtained as described above was coated at -30-90KV using an electrostatic powder coating machine or the like.
It is charged with electricity and applied inside the mold. The thickness of the coating film is determined depending on necessity, but is usually about 10 to 200 μm.

Then, the conductive powder resin composition is electrostatically applied thereon at -30KV to -90KV in the same manner as described above. The film thickness is preferably about 10 to 200 μm.

Finally, fill the mold with plastic material,
Each is molded at a predetermined temperature and/or pressure.
In this way, each powdered resin composition in the mold is anchored and adhered to the molded plastic surface by the heat of the plastic material and/or the heat of molding, etc., and a plastic molded body having a uniform insulating and conductive coating on the surface is obtained. It will be done.

The method of the present invention will be explained with reference to drawings regarding a typical injection molding method. FIG. 1 is a schematic diagram showing the method of the present invention, and FIG. 2 is an enlarged view of the dotted line portion of step E in FIG. 1. , FIG. 3 is an enlarged view of the main part of the obtained plastic molded body.

As shown in FIG. 1, in the pre-process A, a masking material 5 is fixed to unnecessary parts of the fixed mold 3a.

In coating step B, the electrostatic coating machine 6 coats the insulating powder resin composition 2a on the surface of the fixed mold 3a. Next, in a coating step D, the electroconductive powder resin composition 4a is coated with the electrostatic coating machine 6'.
is applied to the insulating powdered resin composition coating 2a.

Finally, the masking material is removed and, if necessary, heated in a heating step E to plasticize the applied powdered resin compositions 2a and 4a.

Next, in the molding process F, the movable mold 3b is placed on the fixed mold 3a and the mold is closed, and a filling hole 3 is formed in the gap in the mold.
The molten plastic material is filled from b' and molded, and the conductive coating 4 and the insulating coating 2 are anchored and adhered to the surface of the plastic molded body 1.

In the demolding step G, the molded plastic body 1 having a coating 2 with a conductive function and a coating 4 with an insulating function on its surface is opened and taken out.

In this way, a plastic molded article having a conductive coating and an insulating coating of uniform thickness can be efficiently obtained.

In the molding method of the present invention, the mold is preheated in advance, or in the case of a room temperature mold or a mold with a low preheating temperature, the powdered resin composition is coated with hot air,
It is preferable to heat with electricity, infrared rays, etc.
By doing so, it is possible to prevent scattering of the powdered resin composition adhered only by electrostatic force by electrostatic coating.

Note that the preheating of the mold refers to a case where the mold temperature is higher than room temperature due to heat applied from the outside or heat generated during molding of a plastic material.

In addition, heating after applying the powdered resin composition,
Refers to heating after applying an insulating powdered resin composition and/or heating after applying a conductive powdered resin composition, to the extent that the resin in the resin composition partially softens and melts and the powder particles adhere to each other. It is preferable to

In addition, when heating is performed only after applying the conductive powdery resin composition, heating is performed to the extent that either or both of the insulating powdery resin composition and the conductive powdery resin composition are fused or cured.

In the method of the present invention, in particular, injection molding methods, blow molding methods in which the plastic material is injected under pressure or the plastic material moves during molding,
Alternatively, in a vacuum forming method, etc., the mold preheating temperature and the softening point and melting point of the resin in the powdered resin composition may be within the range of (melting point + 10°C) ≧ mold preheating temperature ≧ softening point. Particularly preferred.

If the mold preheating temperature is lower than the softening point of the resin, the adhesion between the mold and the powdered resin composition will be low, leading to the movement of the plastic material due to the pressure applied to the plastic material during molding and the injection speed during injection. The powdered resin composition moves or scatters due to pressure and the like, making it difficult to obtain a uniform coating. Additionally, if the mold preheating temperature exceeds (resin melting point + 10°C), the powdered resin composition will completely melt after application.
It becomes fluid and moves due to movement of the plastic material, injection speed, pressure, etc., as described above, making it difficult to obtain a uniform coating. Particularly in the injection molding method, undesirable problems may occur, such as a striped coating or a molded article having no coating at all, especially in the vicinity of the injection port (nozzle).

(Effects of the Invention) As described above, according to the method of the present invention, safety and hygiene problems due to organic solvent volatilization, powder paint scattering, adhesion to the outside of the mold, uneven film thickness, etc. can be avoided. This problem has been solved, and the powdered resin composition containing a high concentration of conductive fine powder can be efficiently and uniformly attached to the plastic surface.
Since the conductive film is covered with an insulating film, it has the advantage of completely eliminating accidents such as electric shock and leakage, and can also provide electromagnetic wave shielding, aesthetic appeal, and antistatic properties at the same time.

Furthermore, according to the method of the present invention, it is possible to color the insulating coating, so it is possible to color the insulating coating only on the inner surface of a box-like object, for example, because the colors of conventional conductive coatings were limited or due to reasons such as electric shock. It became possible to use a conductive coating on the outside of a box-like object, which was previously unusable.

Hereinafter, the present invention will be explained in detail with reference to Examples.
"Parts" or "%" are expressed as "parts by weight" or "% by weight." Prior to Examples, powdered resin compositions were manufactured using the formulations shown below.

Manufacture of insulating powder resin composition [Formulation 1] Epoxy resin 64% Dicyandiamide 5% Titanium oxide (rutile type) 30% Flow aid 1% The epoxy resin is manufactured by Ciel Chemical Co., Ltd. under the trade name Epicote #1004 (epoxy Equivalent weight 875-975, melting point 98℃,
Softening point: 70°C) was used, and Modaflow (trade name, manufactured by Monsanto) was used as a flow aid.

After mixing the composition of Formulation 1 above and kneading at 110°C or lower using a heating roller, the kneaded mixture is cooled and pulverized using a pulverizer. Composition (A-1)
Created as.

[Formulation 2] Epoxy resin 25% Methyl ethyl ketone 50% SnO ₂ coated titanium oxide 25% The epoxy resin is manufactured by Ciel Chemical Co., Ltd. under the trade name Epicoat #1002 (epoxy equivalent 600-700, melting point 83°C,
A mixture of #1004 (melting point 92°C, softening point 65°C) and #1004 (melting point 92°C, softening point 65°C) was also used _.
The coated titanium oxide is manufactured by Mitsubishi Metals Co., Ltd. under the trade name W-10.
(average particle size of about 0.2 μm) was used.

The composition consisting of Formulation 2 was dispersed for 2 hours using a magnetic pot mill to obtain a liquid composition. Next, the liquid composition was sprayed into 3000 parts of water at a temperature of 20° C. or less under high speed stirring to emulsify the liquid composition and extract the solvent into the water to form resin particles.

After that, filtration and water washing were repeated to obtain resin particles with an average particle diameter of about 100 μm. After adjusting the water content to around 50%, dispersion was performed using a ball mill to finely crush the resin particles to form a slurry powder. A resin composition was obtained. After repeating water washing three times or more, filter, dry in dry air at 20℃ or less, crush,
The mixture was sieved (100 meshes) to prepare an insulating powdery resin composition (A-2).

[Formulation 3] Epoxy resin 45% Azo red pigment 4.5% Flow aid (same as Formulation 1) 0.5% Methyl ethyl ketone 50% The epoxy resin used was Epikoat #1002 manufactured by Ciel Chemical Co., Ltd.

An insulating powdery resin composition (A-3) was prepared using the composition of Formulation 3 in the same manner as Formulation 2.

[Formulation 3] Epoxy resin 96% Hardening agent 4% The epoxy resin is manufactured by Ciel Chemical Co., Ltd. under the trade name Epicote #1002, #1004 and #1007 (epoxy equivalent
1750-2200, melting point 128℃, softening point 85℃) 1:
A mixture of 1:7 (melting point: 121°C, softening point: 77°C) was used, and the curing agent used was an imidazole-based epoxy resin curing agent [trade name: Cyuazol C ₁₁ Z, manufactured by Shikoku Kasei Kogyo Co., Ltd.].

After kneading the composition of Formulation 4 at 140° C. or lower using a heating roller, an insulating powdery resin composition (A-4) was prepared in the same manner as Formulation 1.

[Formulation 5] Polyester resin 95% Phthalocyanine blue 5% The polyester resin used was Dainippon Ink Chemical Co., Ltd. trade name Fine Dix M-8000 (melting point 123°C, softening point 75°C).

After kneading the composition of [Formulation 5] above at 135°C or lower using a heating roller, an insulating powdery resin composition (A-5) was prepared in the same manner as [Formulation 1].

[Formulation 6] Polyester resin 99% Flow aid (same as Formulation 1) 1% The above polyester resin is a product name of Nippon U-Pica Co., Ltd.
GV-110 (melting point 85°C, softening point 65°C) was used.

The composition of Formulation 6 was kneaded at 100° C. or below using a heating roller, and then an insulating powdery resin composition (A-6) was prepared in the same manner as Formulation 1.

[Formulation 7] After kneading acrylic resin (trade name A-224S, manufactured by Dainippon Ink and Chemicals Co., Ltd.: melting point 114°C, softening point 70°C) at a temperature of 130°C or lower using a heated roller,
Insulating powder resin composition (A
-7) was created.

Production of conductive powdered resin composition [Formulation 8] Epoxy resin 12% Dendrite-shaped copper powder 48% Flow aid (same as Formulation 1) 1% Methyl ethyl ketone 39% The epoxy resin is manufactured by Ciel Chemical Co., Ltd. under the trade name Epicote #1002 was used as the dendrite-shaped copper powder, and electrolytic copper powder trade name MD-1 manufactured by Mitsui Mining and Mining Co., Ltd. [80% or more passed through 325 mesh (opening 44μ)] was used.

The composition consisting of the above formulation was dispersed in a magnetic pot mill for 2 hours to obtain a liquid composition.

Next, the liquid composition was sprayed into 3000 parts of water at a temperature of 20° C. or less under high speed stirring to emulsify the liquid composition and extract the solvent into the water to form resin particles. Thereafter, filtration and water washing were repeated to obtain resin particles with an average particle diameter of about 100 μm.
After adjusting the water content to around 50%, the resin particles were further finely pulverized to obtain a slurry-like powdered resin composition. Furthermore, after repeating water washing three times or more, it is filtered, dried under dry air at 20℃ or less, crushed, and sieved (150 meshes) to obtain conductive fine powder/resin.
80/20 (weight ratio) conductive powder resin composition (B
-1) was created.

[Formulation 9] Epoxy resin 9% Dendrite-shaped copper powder 51% Flow aid (same as Formulation 1) 1% Methyl ethyl ketone 39% Epoxy resin is manufactured by Ciel Chemical Co., Ltd. under the trade name Epicote #1001 (epoxy equivalent 450-500, melting point 69℃, softening point 50℃), and the dendrite-shaped copper powders are electrolytic copper powders manufactured by Mitsui Mining & Mining Co., Ltd. under the trade names MD-1 and MF-D _2.
(weight average particle size: 8 μm) were mixed in a 1:1 ratio by weight.

After creating a liquid composition in the same way as formulation 8,
A conductive powder resin composition (B-2) having a conductive fine powder/resin ratio of 85/15 (weight ratio) was prepared in the same manner.

[Formulation 10] Epoxy resin 6% Dendrite-shaped copper powder 54% Flow aid (same as Formulation 1) 1% Methyl ethyl ketone 39% Epoxy resin is manufactured by Ciba Geigy Corporation under the trade name Araldite 6097 (epoxy equivalent 900-1000, melting point 100°C) ,
The dendrite-shaped copper powder used was electrolytic copper powder MF-D ₂ manufactured by Mitsui Mining & Mining Co., Ltd., respectively.

The composition having the above formulation was dispersed in a paint shaker for 1 hour to obtain a liquid composition.

Next, after creating a conductive powdered resin composition in the same manner as Formulation 8, a curing agent for imidazole-based epoxy resin [the above-mentioned Cyuazole] was added as a curing agent.
C ₁₁ Z] were dry mixed as fine powder at a ratio of 4phr to prepare a conductive powder resin composition (B-3) having a conductive fine powder/resin ratio of 90/10 (weight ratio).

[Formulation 11] Epoxy resin 15% Nickel powder 45% Flow aid (same as Formulation 1) 1% Methyl ethyl ketone 39% The epoxy resin is made by Ciel Chemical Co., Ltd. under the trade name Epicote #1001, #1002, and #1004. :1:1
(weight ratio) (melting point: 86° C., softening point: 58° C.), and nickel powder manufactured by Inco Co., Ltd. under the trade name #255 (average particle diameter of approximately 2 to 3 μm) was used.

The composition consisting of the above formulation was made into a liquid composition in exactly the same manner as Formulation 10, and the conductive powder resin composition (conductive fine powder/resin = 75/25 (weight ratio)) was prepared in the same manner as Formulation 8. B-4) was created.

[Composition 12] Epoxy resin 12% Nickel powder 48% Methyl ethyl ketone 40% The epoxy resin is manufactured by Ciel Chemical Co., Ltd. under the trade name Epicote #1002, #1004, and #1007 in a 1:1:1 ratio.
(weight ratio) (melting point approximately 107℃,
Softening point: 65℃), and nickel powder made by Inco Co., Ltd. under the trade name #123 (average particle size of about 3 to 7μ) and #255 at 1:1.
A mixture of 1 (weight ratio) was used.

The composition consisting of the above formulation was dispersed in the same manner as Formulation 10 to prepare a liquid composition.

Next, in the same manner as in Formulation 8, a conductive powdery resin composition (B-5) having a conductive fine powder/resin ratio of 80/20 (weight ratio) was prepared from the liquid composition.

[Formulation 13] Epoxy resin 9% Nickel powder (same as formulation 11) 51% Methyl ethyl ketone 40% Epoxy resin manufactured by Ciel Chemical Co., Ltd. Product name Epicote #1002, #1004, #1007, and #1009 (epoxy equivalent 2400-3300 (melting point: about 148°C, softening point: 90°C) in a ratio of 1:1:2:2 (weight ratio) (melting point: about 135°C, softening point: 75°C) was used.

A conductive powdery resin composition (B-6) having a conductive fine powder/resin ratio of 85/15 (weight ratio) was prepared using the composition consisting of the above formulation in the same manner as in Formulation 10.

[Formulation 14] Epoxy resin 11% Silver powder 48% Methyl ethyl ketone 40% Dicyandiamide 1% The epoxy resin is Epicoat #1007, and the silver powder is conductive silver powder (average particle size approximately 1 μm) manufactured by Fukuda Metal Foil & Powder Industries Co., Ltd. used each.

A liquid composition was prepared using the composition described above in the same manner as in Formulation 8, and then diluted by adding 50 parts of methyl ethyl ketone to 100 parts of the composition, followed by spray drying (air flow rate: 20 parts).
conductive powder resin composition with conductive fine powder/ ^resin = 80/20 (weight ratio). Product (B-7) was created.

[Formulation 15] Polyester resin (same as formulation 5) 12% Dendrite-shaped copper powder (same as formulation 9) 48% Methyl ethyl ketone 40% The composition consisting of the above formulation was dispersed in a magnetic pot mill for 1.5 hours to form a liquid composition. The conductive fine powder/
A conductive powdery resin composition (B-8) with resin=80/20 (weight ratio) was prepared.

[Formulation 16] Polyester resin (same as formulation 15) 12% Nickel powder (same as formulation 12) 48% Methyl ethyl ketone 40% A composition consisting of the above formulation was prepared in the same manner as formulation 14, and conductive fine powder/resin = 80/20. (weight ratio) A conductive powdery resin composition (B-8) was prepared.

[Formulation 17] Polyester resin (same as formulation 6) 9% Copper powder 51% Methyl ethyl ketone 40% Copper powder is manufactured by Fukuda Metal Foil & Powder Co., Ltd. under the trade name 4L3 (350
95% or more of mesh pass) were used.

A conductive powdery resin composition (B-10) with conductive fine powder/resin=85/15 (weight ratio) was prepared by using the composition having the above formulation in the same manner as Blend 15.

[Formulation 18] Acrylic resin (same as formulation 7) 9% Nickel powder (same as formulation 11) 51% Methyl ethyl ketone 40% A composition consisting of the above formulation was prepared in the same manner as formulation 12 to obtain conductive fine powder/resin = 85/15. (weight ratio) A conductive powdery resin composition (B-11) was prepared.

Example 1 After masking the non-painted part in the fixed mold that had been preheated to 80°C, an insulating powdered resin composition (A-
1) was electrostatically coated under a voltage of -80KV to form a coating film. Then, in order to finally measure the surface resistance value of the conductive coating film, a portion of the masking corresponding to both ends of the molded article was removed.

Thereafter, the conductive powder resin composition (B-1) was electrostatically applied under a voltage of -40 KV to form a coating film, and the remaining masking was removed, and the fixed mold and the movable mold were sealed.

Then, a heat-resistant polystyrene resin liquid with a resin temperature of 270°C was injection molded at an injection pressure of about 900 kg/cm ² .

Thus, the film thickness is 40 μm and the surface resistance value is 0.85 ohm/
□ Uniform and highly conductive film and a thick white film on top of it.
A heat-resistant polystyrene molded body having an insulating coating of 40 μm was obtained.

The obtained conductive film was measured with a spectrum analyzer TR4172 manufactured by Takeda Riken Co., Ltd., and had a frequency of 50MHz.
It showed an excellent shielding effect of 50 to 40 dB in the ratio of incident electromagnetic wave intensity/emitted electromagnetic wave intensity against electric field electromagnetic waves of ~1000 MHz.

Example 2 The unpainted part of the fixed mold, which had been preheated to 60°C, was masked and an insulating powder resin composition (A-
3) was electrostatically coated under a voltage of -70 KV to form a coating film, and then a part of the masking was removed in the same manner as in Example 1. Next, the conductive powder resin composition (B-2) was electrostatically applied under a voltage of -40 KV to form a coating film, and then the remaining masking was removed.

After that, the movable mold and movable mold are sealed, and the resin temperature is
PVC resin liquid at 180℃ is injected at a pressure of approximately 750Kg/
When injection molded in cm ² , a vinyl chloride resin molded product with a uniform, highly conductive film with a film thickness of 60 μm and a surface resistance value of 0.51 ohm/□, and a red insulating film with a film thickness of 40 μm on top of that, was obtained. Obtained.

Example 3 The non-painted parts in a mold preheated to 90°C were masked, and then the insulating powdered resin composition (A-7) was coated with an electrostatic coating device under a voltage of -65KV. After coating the painted portion inside the mold to form a coating film, a portion of the masking was removed in the same manner as in Example 1.

Next, the conductive powder resin composition (B-3) was electrostatically applied under a voltage of -40 KV to form a coating film, and then the remaining masking was removed. After that, a hard vinyl chloride sheet is heated to 125% by heating.
℃ to soften it, fix it to the mold with a clamp frame, and then use a vacuum pump to suck out the air inside the mold at a vacuum level of 720 mmHg.
When the sheet was closely attached to the mold surface and molded, the film thickness was 60μ
A hard vinyl chloride resin molded body was obtained, which had a uniform and highly conductive film with a surface resistance value of 0.45 ohm/□ and a transparent insulating film with a thickness of 40 μm thereon.

Example 4 The unpainted part of the fixed mold, which had been preheated to 70°C, was masked and an insulating powder resin composition (A-
3) was electrostatically coated under a voltage of -60 KV to form a coating film, and then a part of the masking was removed in the same manner as in Example 1.

Next, the conductive powder resin composition (B-4) was electrostatically applied under a voltage of -40 KV to form a coating film, and then the remaining masking was removed.

After that, the fixed mold and the movable mold are sealed, and polyethylene resin liquid with a resin temperature of 220°C is injected at a pressure of approximately 1100°C.
When injection molded at Kg/cm ² , a uniform, highly conductive film with a film thickness of 50 μm and a surface resistance value of 1.1 ohm/□ was obtained, and on top of that a white insulating (antistatic) film with a film thickness of 50 μm. A polyethylene resin molded article having the following properties was obtained.

Example 5 The non-painted part in the fixed mold at a temperature of 80°C was masked, and the insulating powdered resin composition (A-6) was applied.
After electrostatic painting under a voltage of 70 KV, a portion of the masking was removed as in Example 1.

Next, the conductive powdered resin composition (B-5) was electrostatically applied under a voltage of -40KV to form a coating film, the remaining masking was removed, and the mold was heated to 95°C using an infrared heater. A coating film was formed.

After that, the fixed mold and the movable mold are sealed, and ABS resin liquid with a resin temperature of 230℃ is injection molded at an injection pressure of approximately 1000Kg/cm ² to achieve a film thickness of 60μm and a surface resistance value of 0.55/□.
A uniform and highly conductive film with a film thickness of 50 μm on top of it.
An ABS resin molded body having a transparent insulating film of m was obtained.

Example 6 The unpainted part of the inner surface of the mold, which had been preheated to 87°C, was masked, and the insulating powder resin composition (A-5) was applied to -60KV using an electrostatic powder coating device.
After painting the painted part of the inner surface of the mold under voltage,
As in Example 1, a portion of the masking was removed.

After electrostatically coating the conductive powder resin composition (B-6) under a voltage of -60 KV, the remaining masking was removed, and the inner surface of the mold was heated with an infrared heater to bring the temperature of the mold to 100°C.

Thereafter, polypropylene extruded into a tube shape at 195℃ was inserted into the mold, and 3.5Kg/cm ² of compressed air was blown into the tube to expand it.
When polypropylene was closely attached to the inner surface of the mold and molded, a polypropylene resin with a uniform, highly conductive film with a film thickness of 60 μm and a surface resistance value of 0.39 ohms/□, and a blue insulating film with a film thickness of 50 μm on top of that film was obtained. A molded body was obtained.

Example 7 The non-painted parts of the mold were preheated to 105°C, and the insulating powder resin composition (A-4) was coated at -70KV using an electrostatic powder coating device.
After applying the coating to the painted area in the mold under voltage to form a coating film, a part of the masking was removed in the same manner as in Example 1.

Next, the conductive powder resin composition (B-7) was electrostatically applied under a voltage of -40 KV to form a coating film, and then the remaining masking was removed.

After that, phenolic resin powder preheated to 116℃ was put into the mold, the mold was closed, heated to 155℃, and the mold was compressed with a pressure of 180Kg/ ^cm2.The film thickness was 50μm and the surface resistance value was A phenolic resin molded body was obtained which had a uniformly conductive film of 0.2 ohm/□ and a transparent insulating film with a thickness of 40 μm thereon.

Example 8 The insulating powder resin composition (A-4) was preheated to 120°C, masked the non-painted parts in the mold, and
was electrostatically coated under a voltage of -70 KV to form a coating film, and then the masking was partially removed in the same manner as in Example 1.

Next, the conductive powder resin composition (B-8) was electrostatically applied under a voltage of -40 KV to form a coating film, and then the remaining masking was removed.

After that, the fixed mold and the movable mold are sealed, and the polycarbonate resin liquid with a resin temperature of 260℃ is injected under pressure.
Injection molded at 1500Kg/ ^cm2 to create a uniform and highly conductive film with a film thickness of 40μm and a surface resistance value of 1.05Ω/□.
A polycarbonate resin molded body having a transparent insulating film with a thickness of 50 μm thereon was obtained.

Example 9 The insulating powdered resin composition (A-
5) was applied electrostatically under an electrostatic voltage of -60 KV to form a coating film, and then a part of the masking was removed in the same manner as in Example 1 above.

Then, after electrostatically coating the conductive powder resin composition (B-9) under a voltage of -40 KV, the remaining masking was removed.

After that, the fixed mold and the movable mold are sealed, and PPO (polyphenylene oxide) resin with a resin temperature of 330°C is injection molded at an injection pressure of 1500 kg/cm ² , with an average film thickness of
A PPO resin molded body was obtained, which had a highly conductive film with a thickness of 50 μm and a surface resistance value of 1.2 ohms/□, and a blue insulating film with a thickness of 40 μm thereon.

Example 10 The unpainted part of the inner surface of a mold that had been preheated to 80°C was masked, and the insulating powder resin composition (A-7) was applied to the painted part of the mold using an electrostatic powder coating device. After painting, a part of the masking was removed in the same manner as in Example 1.

Then, after electrostatically coating the conductive powder resin composition (B-10) under a voltage of -40 KV, the remaining masking was removed.

After that, the polyethylene resin extruded into a tube shape at 175℃ was inserted into the mold, and 3.2Kg/
When compressed air of ² cm2 was blown into the tube and the tube was inflated and molded, it formed a uniform, highly conductive film with a film thickness of 60 μm and a surface resistance value of 0.65 ohm/□, and on top of that a transparent film with a film thickness of 40 μm. A polyethylene resin molded body having an insulating film was obtained.

Example 11 The unpainted parts of the mold, which had been preheated to 105°C, were masked and an insulating powdered resin composition (A-
7) was applied electrostatically at a voltage of -80 KV to form a coating film, and then a part of the masking was removed in the same manner as in Example 1.

Then, after electrostatically coating the conductive powder resin composition (B-11) under a voltage of -40 KV, the remaining masking was removed.

After that, the fixed mold and the movable mold are sealed, and polypropylene resin liquid with a resin temperature of 240°C is injected at a pressure of 1500°C.
Injection molded at Kg/ ^cm2 , film thickness 60μm, surface resistance value
A uniform, highly conductive coating of 0.55 ohm/□,
A polypropylene resin molded body having a transparent insulating film with a thickness of 40 μm thereon was obtained.

[Brief explanation of the drawing]

FIGS. 1A to 1G are process schematic diagrams showing an injection molding method that is an example of the method of the present invention. FIG. 2 is an enlarged view of the dotted line in step E in FIG. 1, and FIG. 3 is an enlarged sectional view of a plastic molded article obtained by the method of the present invention. DESCRIPTION OF SYMBOLS 1... Plastic molded object, 2... Insulating coating, 3... Molding mold, 4... Conductive coating, 5...
Masking material, 6... Electrostatic coating machine.

Claims (1)

[Claims] 1. In a plastic molding method, first an insulating powdered resin composition is applied into a mold by electrostatic coating, and then a conductive powdered resin composition is electrostatically coated on top of the insulating powdered resin composition. Filling and molding plastic material,
A thermosetting or thermoplastic resin coating is attached to the bare surface of the molded plastic by plasticizing and compressing the powdered resin composition using the heat of the filling material and/or the heat during molding. A plastic molding method that forms a multilayer film. 2 The insulating powder resin composition contains a coloring pigment of 0.5 to
The plastic molding method according to claim 1, wherein the thermoplastic or thermosetting powder resin composition contains a thermoplastic or thermosetting powder resin composition in the range of 50% by weight. 3 The conductive powder resin composition contains conductive fine powder.
Claim 1, which is a thermoplastic or thermosetting powdery resin composition containing in the range of 70 to 95% by weight.
Plastic molding method described in section. 4. The plastic molding method according to claim 1, wherein the plastic molding method is an injection molding method, a blow molding method, a transfer molding method, or a vacuum molding method. 5. The plastic molding method according to claim 1, wherein the mold is a preheated mold. 6. The method according to claim 1, in which the conductive powder resin composition is applied by electrostatic coating and then heated to fuse or harden the insulating and/or conductive powder resin composition. Plastic molding method. 7. A patent in which the melting point and softening point of each resin component used in the insulating and conductive powder resin composition and the mold preheating temperature are in the range of (melting point + 10°C) ≧ mold preheating temperature ≧ softening point. A plastic molding method according to claim 5. 8 The conductive powder resin composition contains a water-soluble solvent,
A powdered resin composition obtained by a wet granulation method in which a liquid composition comprising the water-insoluble and solvent-soluble resin and conductive fine powder is dispersed in water, granulated, extracted with a solvent, separated, and dried. A plastic molding method according to claim 1, wherein the plastic molding method is a plastic molding method. 9 The insulating powder resin composition contains a water-soluble solvent,
A powdered resin obtained by a wet granulation method in which a liquid composition consisting of the water-insoluble and solvent-soluble resin and, if necessary, a colored pigment, is dispersed in water, granulated, extracted with a solvent, separated, and dried. The plastic molding method according to claim 1, which is a composition. 10. The plastic molding method according to claim 1 or 3, wherein the conductive fine powder is a dendrite-shaped metal powder.