JPS6336627B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of applying a surface modifier to a synthetic resin molded article.

Conventional antistatic treatments can be roughly divided into coating methods and kneading methods, but the coating method requires more steps to apply antistatic agent to the surface of the synthetic resin molded product, making the work more labor-intensive and reducing the amount of antistatic agent applied. The membrane becomes thicker;
There was a risk that it would gradually peel off due to contact with other objects, and its durability was poor. In addition, in the kneading method, an antistatic agent is mixed into the raw material in advance, and after molding, the antistatic agent bleeds onto the surface to form a film, but since the antistatic agent is kneaded into the raw material, physical properties may change. It had a negative impact and was not desirable.

This invention was made in view of these points, and focuses mainly on the reduced pressure state that occurs during mold release such as injection molding of synthetic resins, and the heat of the molded product immediately after mold release. In these cooling or mold release treatments, a solution or aqueous dispersion containing a surface modifier such as an antistatic agent containing water or an organic solvent was formed. An aerosol consisting of a large number of particles is attached to the above-mentioned molded product, and at the same time as the molded product is cooled or released from the mold, an ultra-thin film made of the above-mentioned surface modifier is quickly formed on the surface of the synthetic resin molded product, thereby extremely efficiently. The purpose of this invention is to provide a coating method that provides a uniform ultra-thin film.

The method of the present invention will be explained below with reference to the drawings.

First, an aerosol generator 1 is prepared, and in this generator 1, a solution 2 containing 90% water and consisting of an antistatic agent is made, and this is mixed into a large number of particles (particle size 1 to 1).
(preferably 50μ). On the other hand, synthetic resin molded product 6 from male mold 4 and female mold 5
After molding, at the same time as separating the female mold 5 from the molded product 6,
The aerosol is sprayed from the aerosol generator 1 through the pipe 7 and the switching valve 8 onto the synthetic resin molded product 6 by the ejector 9. When the female mold 5 is separated from the male mold 4, a reduced pressure is created between the molds 4 and 5, and the aerosol particles 3 are strongly attracted to the area, and the particles 3 adhere to the surface of the molded product 6. The surface of this molded product 6 is still hot since it has just been released from the female mold 5, and therefore the water in the large number of particles 3 immediately evaporates.
The antistatic agent adheres to the surface as a film. The aerosol particles 3 are difficult to adhere to the film thus deposited, and the particles 3 are deposited one after another in the immediate vicinity of the film, and this process is repeated until a uniform ultra-thin film made of the antistatic agent is formed on the synthetic resin molded product 6. Formed on the entire outer surface. As a result, the synthetic resin molded product 6 is cooled and can be easily removed from the male mold 4. Then switching valve 8
The remaining aerosol between the male mold 4 and the female mold 5 is sucked by the suction device 10 from the ejector 9 through the pipe 11, and the aerosol between the male mold 4 and the female mold 5 is wiped out.

In place of this embodiment, FIG. 2 shows that when the male die 5 is released, an aerosol is sent directly into the female die 5 from the aerosol generator 1 through the pipe 12, and the synthetic resin molded product 6 is
It is also possible to create a highly concentrated aerosol atmosphere outward. In addition, 13 in FIG. 2 is a check valve provided at the aerosol spout 5a of the female mold 5, and the pin 13a
The valve 13 can be opened and closed by moving it as shown by the arrow.

In this way, in these embodiments, the synthetic resin molded product 6 is molded using the male mold 4 and the female mold 5, and the aerosol is sprayed into the reduced pressure state with the female mold 5 separated, so that the aerosol is dispersed between the molds 4 and 5. is strongly attracted to
Therefore, the aerosol easily adheres to the molded product 6. In general, an aerosol composed of minute particles 3 has a larger surface area and is more likely to vaporize as the particle size becomes smaller, but on the other hand, it is less likely to adhere to the surface of a synthetic resin molded product. However, in the present invention, as described above, even minute particles 3 having heat tend to adhere to the surface of the synthetic resin molded product 6.

Moreover, since the molded product 6 has heat, the moisture in the attached aerosol particles 3 instantly evaporates, and a thin film made of the evaporated antistatic agent adheres to the surface of the molded product 6, and is uniformly formed by the large number of particles 3. An extremely thin film can be obtained. Furthermore, the molded product 6 is cooled at the same time as this ultra-thin film is formed, so that it can be easily removed from the male mold 4, making the molding cycle quick and simple. Moreover, since the molded product 6 is cooled while being retained in the male die 4, the dimensions after molding are stabilized. Furthermore, if a surface modifier such as an antistatic agent does not enter the molded product 6 and the molded product 6 is a food container or the like, it is safe from a food hygiene perspective.

FIG. 3 shows yet another embodiment, in which an extremely thin film made of an antistatic agent is formed on the inner surface of the molded product 6. That is, after separating the female mold 5 from the molded product 6, by pushing the pin 14 that passed through the male mold 4, the molded product 6 locked to the male mold 4 is released from the male mold 4, and the inside of this molded product 6 is released. Aerosols enter the sides. At this time, as in the above embodiment, when the molded product 6 is removed from the male mold 4, the pressure between the male mold 4 and the molded product 6 is reduced, the aerosol particles 3 are sucked into the molded product 6, and the molded product The inner surface of item 6 also still has heat. Therefore, as in the above embodiment, a uniform ultra-thin film made of the antistatic agent can be formed on the inner surface of the molded product 6 as well.

Further, FIG. 4 shows a method in which an extremely thin film made of an antistatic agent is formed on the inner and outer surfaces of a synthetic resin molded product 6, which can be easily implemented by combining the embodiments shown in FIGS. 2 and 3 above.

Furthermore, as shown in FIG. 5, instead of the embodiment shown in FIG. 1, a peripheral wall plate 15 is made to protrude from the outer periphery of the male mold 4, and the female mold 5 is made to slide within the tip of this peripheral wall plate 15, so that the male mold 4 always , a female mold 5 and a peripheral wall plate 15 form a sealed chamber 16. As a result, when the female mold 5 is released after molding the molded product 6, the pressure inside the sealed chamber 16 is strongly reduced, and the aerosol is sucked into the sealed chamber 16.

After the aerosol adheres to the molded product 6, an appropriate door (not shown) provided on the peripheral wall plate 15 is opened, the molded product 6 is taken out, the door is closed again, and the female mold is used to mold the next molded product 6. By pushing back 5, the sealed chamber 16 becomes extremely small, and the aerosol in the sealed chamber 16 is exhausted. Furthermore, this cycle is made automatic, and when the female mold 5 separates from the male mold 4, the aerosol is sucked into the sealed chamber 16, and thereby the aerosol adheres to the outer periphery of the molded product 6. Then, when the female mold 5 returns, the above-mentioned door opens automatically, and the molded product 6 is transferred from the male mold 4 to the molded product 6.
may come off and fall outside the sealed chamber 16, and at the same time the aerosol remaining in the sealed chamber may also be exhausted from the door to the outside of the sealed chamber 16. In this manner, in this embodiment, an extremely thin film made of an antistatic agent can be formed on the molded product 6 more efficiently.

Furthermore, in place of the above embodiment, it is of course possible to apply different types of surface modifiers to the inner and outer surfaces of the molded product.

Further, in the above embodiment, when spraying the aerosol onto the inner surface of the molded product 6, if the mold release agent alone or together with other surface modifiers is mixed with the aerosol, the mold releasability will be improved.

In the above examples, an antistatic agent was used, but the same effect can be obtained by applying an appropriate surface modifier such as a mold release agent, an antifogging agent, a rust preventive agent, or a fungicide. Of course, it also has the following.

As described above, the present invention uses the reduced pressure state that occurs when releasing the mold during synthetic resin molding to draw an aerosol formed from a solution containing a surface modifier into the mold and deposit it on the inner and outer surfaces of the molded product. A uniform ultra-thin film made of a surface modifier can be extremely easily formed on the inner and outer surfaces of a synthetic resin molded product, and at the same time, the molded product and the inside of the mold can be cooled to simplify and speed up the molding cycle. has advantages. Generally, when releasing the mold, a peeling charge is generated on the outer periphery of the molded product, and as a result, the surrounding mold release agent and debris are attracted to this static electricity and adhere to the outer periphery of the molded product. Aerosols floating in the atmosphere are sucked, further promoting the adhesion of aerosols to the outer periphery of the molded product. Furthermore, in the case of lightweight molded products, they are easily affected by the static electricity mentioned above, and when the mold is released, it may adhere to one mold and not be easily peeled off from the mold. However, in this invention, an antistatic agent is added to the surface modifier. If used, static electricity caused by peel-off charging can be quickly removed, and the molded product can be easily peeled off. Moreover, this invention can be applied to injection molding, blow molding, compression methods, and other methods that use a wide mold.

[Brief explanation of the drawing]

FIG. 1, FIG. 2, FIG. 3, FIG. 4, and FIG. 5 are explanatory diagrams showing each embodiment of the present invention. In the figure, 1 is the aerosol generator, 2 is the solution, and 3 is the aerosol generator.
1 is a particle, 4 is a male mold, 5 is a female mold, 6 is a synthetic resin molded product, 9 is an ejector, and 10 is a suction device.

Claims (1)

[Claims] 1 A solution containing a surface modifier is made into an aerosol consisting of a large number of particles, and the aerosol is introduced into the reduced pressure atmosphere between the male and female molds, which is created when one or both of the molds is released during synthetic resin molding. A synthetic resin characterized in that the aerosol is attached to the surface of the molded product that has been sprayed and released from the mold, and at the same time as the molded product is cooled, an extremely thin film made of a surface modifier is formed on the surface of the molded product. A method of applying surface modifiers to molded products.