JP2937365B2 - Method for producing molding material for getter of electric switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a method for producing a pellet-shaped getter molding material used as a material of a molded product constituting a part of an electric switch such as a relay or a switch.

[Prior art]

In an electric device having a contact, such as an electric switch such as a relay or a switch, when an organic gas is generated in the device, an organic substance may adhere to the contact and cause a contact failure. Particularly, in the case of a sealed type, since the organic gas does not escape to the outside, the problem of the contact reliability of such a contact is great. Therefore, a molded article constituting a part of electric equipment is molded using a molding material in which activated carbon powder having an effect of adsorbing organic gas (ie, a getter effect) is mixed with a synthetic resin, and activated carbon contained in the molded article is formed. It has been studied to prevent the organic gas from affecting the contact by adsorbing the organic gas on the powder. As a molding material having such a getter effect, it is general to use a material prepared by blending and mixing activated carbon powder with synthetic resin pellets.

[Problems to be solved by the invention]

However, activated carbon powder has a size of several tens of μ, whereas pellets of resin molding material are formed in units of mm. It is difficult to uniformly mix the activated carbon into the powder, and the activated carbon powder is unevenly distributed in the getter molding material. Therefore, the activated carbon is also unevenly distributed in the molded article molded using the getter molding material, and when the activated carbon is unevenly distributed, a small molded article having a small content of the activated carbon also occurs. There is a possibility that the problem that the getter effect varies will occur. In addition, when the activated carbon powder is unevenly distributed in the molding material for the getter, the activated carbon powder is clogged in a gap between a nozzle of a molding device, a molding die, and a knockout pin when molding the molding material. May also occur. And because of the problem that activated carbon powder is unevenly distributed, the amount of the activated carbon powder is limited,
It has not been possible to obtain a large getter effect by blending a large amount of activated carbon powder. The present invention has been made in view of the above points, and an object of the present invention is to provide a method for manufacturing a getter molding material for an electric switch that can mix a large amount of activated carbon powder with a uniform distribution. It is.

[Means for Solving the Problems]

A method for producing a getter molding material for an electric switch according to the present invention is characterized in that activated carbon powder is blended with a synthetic resin and then the pellet is formed.

[Operation]

According to the present invention, since the activated carbon powder is blended with the synthetic resin in a pelletized state, the blended distribution of the activated carbon powder can be made uniform by including the activated carbon powder in the pellets.

【Example】

Hereinafter, the present invention will be described in detail with reference to examples. Getter molding material is prepared in powder or liquid form
PPS resin, PBT resin, synthetic resin such as nylon, and glass fiber and other fillers as a reinforcing material, as well as a coloring agent, etc. After mixing or kneading by kneading with a kneading extruder, it can be manufactured by pelletizing the mixture.
Pelletization may be performed by using a pellet forming machine such as a pelletizer, or may be performed by kneading and extruding with the above-described twin-screw kneading extruder by cutting the extruded material with a cutter or the like. In the present invention, the activated carbon powder is blended in any of the mixing step, the kneading step, and the pelletizing step before the pelletizing step, and a getter molding material is prepared as a pellet containing the activated carbon powder. I am trying to do it. By allowing the activated carbon powder to be contained in the pellets in this way, there is no danger that the activated carbon powder is unevenly distributed due to a large difference in particle size, such as in the case of mixing activated carbon powder having a small particle size with a pellet having a large particle size, and uniform. Can be used as a getter molding material. And since the activated carbon powder can be uniformly dispersed without uneven distribution in this way, the activated carbon can be uniformly dispersed even in a molded article molded using the getter molding material, and the getter effect by the activated carbon is reduced. Since the activated carbon powder is not unevenly distributed in the molding material for the getter, the nozzle or knockout of a molding device or a molding die is used when molding the molding material by injection molding or the like. The problem that the activated carbon powder is clogged in the gap between the pins is eliminated. Further, since the activated carbon powder can be uniformly distributed without being unevenly distributed in this manner, it is possible to mix a large amount of the activated carbon powder, and a large getter effect can be obtained by mixing a large amount of the activated carbon powder. It becomes. By using the getter molding material prepared as described above, a molded article constituting an electric switch such as a relay or a switch can be molded. For example, in a sealed electric device such as a metal hermetic sealed relay as shown in FIG. 1, a molded member A for holding the yoke 1 and the contact plates 2, 3 can be formed (FIG. 1). , The molded article member A is indicated with dots). In FIG. 1, 4 is a permanent magnet, 5 is an amateur, 6 is a coil, 7 is a bobbin, 8 is a base, 9 is a cover, 10 is a terminal, 11 is a movable spring plate, and 12 is a card. By forming the molded article member A constituting a part of the interior of the electric device with the getter molding material, the organic gas generated in the electric device is adsorbed on the activated carbon powder in the getter molding material (ie, Getter effect), and can prevent the occurrence of contact failure due to the action of the organic gas on the contact. Since the activated carbon powder is blended in the getter molding material, molding is performed using the getter molding material only in portions where electrical insulation is not required, and activated carbon powder is blended in portions where electrical insulation is required. It is preferable to perform molding using a molding material that is not used. Taking the molded article member A of FIG. 1 as an example, the portion holding the yoke 1 (shown by cross-hatched lines in FIG. 1) does not require electrical insulation, so this portion is molded for getters. It should be molded by primary molding using a material, and the part holding the contact plates 2 and 3 should be molded by secondary molding using a molding material that does not contain activated carbon powder, because electrical insulation is required. Thereby, the molded article member A can be integrally molded. Further, the getter molding material is formed into a sheet shape, and the sheet containing the activated carbon powder can be made to adsorb the organic gas by loading the sheet into an electric device. It is necessary to provide an extra space in the electric device for inserting the sheet, and it is necessary to consider an assembly state for fixing the sheet in the electric device. On the other hand, if the members constituting the electric device are molded using the getter molding material as described above, such a problem does not occur. Here, when molding the molded article member A by injection molding or the like, a thin skin layer of a dense resin is generally formed on the surface of the molded article member A, and the activated carbon contained in the molded article member A is formed. May be covered with the skin layer, and the activated carbon may not sufficiently obtain the effect of adsorbing the organic gas. In this case, it is preferable to use the molded article member A in a state where the surface of the molded article member A is shaved and the skin layer is removed. In shaving the surface of the molded article member A in this way, after shaping the molded article member A constituting a part of the electric equipment into a predetermined shape, the surface is subjected to a polishing treatment such as a honing treatment or a plast treatment. It can be done by doing. The polishing may be performed so that the surface of the molded article member A is shaved to a thickness of about several μm to several tens μm or more in order to remove the skin layer. Further, in addition to performing the polishing process in this manner, a molded product obtained by cutting a molded material and processing the molded material into a predetermined shape of a molded product member A constituting a part of an electric device, thereby shaving and removing a surface skin layer. The member A can be finished. It is also possible to prepare a getter molding material by blending a ceramic powder in place of the activated carbon powder, and in this case also, a getter effect can be obtained by the ceramic powder as in the case of the activated carbon powder. Next, experimental examples of the present invention will be described. Mix and mix 40% by weight of glass fiber and 10% by weight of activated carbon powder with an average particle size of 45μ in PPS resin, and then put this into a twin-screw extruder and extrude it while kneading it, and cut it with a cutter. Thus, pellets having a particle size of 2 to 3 mm were prepared. The pellets were used as a getter material and injected into an injection molding machine, and injection molding was performed to prepare a molded product member for a hermetic seal type relay. Observation of the surface and cut surface of the molded product member revealed that the activated carbon powder was uniformly dispersed. For comparison, PPS with 40% by weight of glass fiber
Activated carbon powder having an average of 45μ is blended and mixed with resin pellets (particle diameter: 2 to 3mm), and the mixture is used as a getter material and injected into an injection molding machine. Observation of the surface and cut surface of the molded product member revealed that the activated carbon powder was partially unevenly distributed, and the distribution of the activated carbon powder was uneven.

【The invention's effect】

As described above, in the present invention, after blending the activated carbon powder with the synthetic resin, this is pelletized. Can be used as a getter molding material in which activated carbon powder is uniformly blended without the risk of uneven distribution, and the getter effect of activated carbon can be stably obtained by uniformly dispersing activated carbon even in a molded article. In addition to this, the problem that the activated carbon powder is clogged in the gap of the nozzle or knockout pin of the molding device or the molding die during molding is also eliminated, and such activated carbon powder is uniformly distributed without being unevenly distributed. Because it can be distributed, a large amount of activated carbon powder can be blended, and a large getter effect can be obtained. That.

[Brief description of the drawings]

FIG. 1 shows an example of a hermetic seal type relay using the getter molding material of the present invention, wherein 1 is a yoke, 2, 3 are terminal plates, and A is a molded product member.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shunichi Nakayama 1048 Oaza Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Works, Ltd. (56) References JP-A-62-35832 (JP, A) (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) B29B 7/00-17/02

Claims (1)

(57) [Claims] 1. A method for producing a getter molding material for an electric switch, wherein activated carbon powder is blended with a synthetic resin and then pelletized.