JPS6246608A - Manufacture of polymeric material molded part - Google Patents

Abstract

PURPOSE:To contrive to effectively prevent poor external appearance (bare) due to residual air by a structure wherein flame-spray films made onto the surface of the cavity of a mold have an infinite number of fine irregularities formed on its surface and fine communicating pores formed in mesh in its interior. CONSTITUTION:As for a mold 1, flame-spray films 3 and 3 are formed on the required locations in the surface of the cavity surfaces 2 and 2 of split molds 1a and 1a. Micro- vent pieces 4 are mounted in such manners that the tip part of each piece pierces through each of the flame-spray films 3 and 3 and exposes itself to a cavity space 2a and the basic end side of each piece is imbedded in each of the split molds 1a and 1a. The cavity space 2a communicates through the vent hole 5 formed in each micro-vent piece 4 and the vent hole 6 communicating to said hole 5 to the exterior of the mold 1. For the forming methods for flame-spray film, any forming method such as gas type spraying and arc type spraying can be used provided that fine irregu larities are made on the surface of the film. Metal and ceramic are suitably used as spraying material. When molding material is supplied in the above-mentioned mold, no development of air pent and remained in the mold occurs and consequently poor external appearance is prevented from developing.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing molded products made from polymeric materials such as rubber, and more specifically, a method for efficiently manufacturing molded products made from polymeric materials having a good appearance. to leap into

Conventionally, in terms of tire manufacturability, a method has been used in which a green tire is fed into a mold and then molded using υl:l sulfur. When the tire is fed into the mold and vulcanized.

Appearance defects (bare) occur due to residual air),
It is common practice to apply a liquid on the outer surface of raw tires to prevent them from pairing. However, applying the liquid on the outer surface in this manner has the problem of complicating the manufacturing process.

In addition, it is safe to provide holes in the mold for air release, but since the molding material is poured into these holes, there is a problem of spillage, which requires a trimming process to remove the spillage after molding. There is an unbelievable complexity.

In this case, use a micro pent piece with a hole diameter of 1 m or less as a hole for air release.

Since the length of the spew is shortened and the diameter is also thinned, there are no problems with appearance, and therefore the trimming process can be omitted. However, as mentioned above, it is necessary to apply the outer surface liquid to the raw rubber to prevent pairing, but if the outer surface liquid is used in this way, the holes in the micro vent piece will quickly become clogged, and even if the outer surface liquid is used, A bear will appear. On the other hand, if the outer surface liquid is not applied, bare spots will occur frequently.

In order to prevent this, the number of micro vent pieces must be significantly increased.

The present invention has been developed in view of the above circumstances, and has excellent features such as eliminating the need to apply a pair-preventing outer surface liquid when vulcanizing green tires, eliminating the formation of bare tires, and omitting the spill trimming process. An object of the present invention is to provide a method for efficiently manufacturing a polymeric material molded article having an external appearance.

That is, in order to achieve the above-mentioned object, the present invention supplies a polymer molding material into a mold, and when manufacturing a polymer molded product, the entire surface of the cavity 71 of the mold, which is in contact with the polymer molding material, is supplied into a mold. Alternatively, a mold is used in which a /18 film is formed on a part of the mold and a micro vent piece is attached to communicate with the inside of the cavity and the outside of the mold.

According to the present invention, the sprayed film is formed on the surface of the mold cavity in this way, and the sprayed film has countless fine irregularities formed on the surface and a network of fine communication holes formed inside. 1, this is effective in preventing poor appearance (bare) due to air residue when a green tire is molded with compressed 7J [ ] sulfur, and it is reliably prevented from applying any external surface liquid. Furthermore, since no external liquid is used, the holes in the micro vent pieces are not clogged, and the number of micro vent pieces can be reduced. Furthermore, since the 71 clopento piece effectively exhibits its function, the step of trimming the spew can be omitted. Therefore, since the process of applying external liquid and trimming spills is omitted, the production of polymer molded products is carried out efficiently, and as mentioned above, bare spots do not occur, and even if spills occur, they are shortened. Since it is thin, it has a good appearance.

Hereinafter, the invention will be explained in more detail with reference to all the drawings.

The uninvented method is suitably adopted for manufacturing rubber molded products such as tires and glass molded products, but in the uninvented method, the mold cavity, which is in contact with the polymer molding material such as a green tire, is used as a mold. A mold with a thermal spray coating on a part of the entire surface and a micro vent piece that communicates with the inside of the cavity and the outside of the mold? use.

=rr, Figure 1.2 shows such a mold (tire mold)
The mold l in Fig. 1 is a split mold la,
Sprayed film 3 on the surface of cavity 2, 2 of la.
3 is formed, and the tip part completely penetrates the sprayed films 3, 3, and extends from the sprayed films 3, 3 to the space between the cavity walls 2aK, and the proximal end is buried in the split molds 1a, 1aK. A micro vent piece 4 is attached. A ventilation hole 5 is formed in this micro vent piece 4, and the cavity space 2a is connected to this ventilation hole 5 and a penthole 6 that communicates with the ventilation hole 5. It communicates with the outside of the mold 1 via the mold 1.

Furthermore, in the mold 1 shown in FIG. 2, the micro vent piece 4 is buried in the split molds 1a, la so that the tip thereof is exposed to the capity surfaces 2, 2, and the tip part t-a
A thermally sprayed film 3.3i is formed.

Here, the sprayed film has countless fine irregularities formed on its surface and a network of fine communicating holes formed inside, but the roughness of the surface is important from the viewpoint of air diffusion effect and appearance. The line average roughness (Ra) is preferably 2.5 to 15 μm, more preferably 2.5 to 6 μm, and the smaller the Ra, the better the appearance of the molded product can be. The thickness of the sprayed film is preferably 20 μm or more, more preferably 50 μm or more, from the viewpoint of male resistance and air diffusion effect.

Any solvent method can be used to form the sprayed film as long as fine irregularities are formed on the surface, such as gas spraying, arc bath spraying, glass spraying, explosive spraying, etc. .

Metals and ceramics can be suitably used as thermal spray materials. As the metal, iron, nickel, aluminum, chromium, stainless steel, cobalt, copper, zinc, bronze, inzoum, molybdenum, titanium, yttrium, etc., and one or more of these alloys are used. Ceramics include gold W4 oxide, carbide, and nitride.

Examples include borides, such as alumina, norconia,
Ittria, silica, titania, magnesia, calcia, nickel oxide, chromia, cobalt oxide, nickel graphite, chromium carbide, titanium carbide, tungsten carbide, boron carbide, solconium carbide, silicon carbide, titanium nitride, turconium night One or more of the following metals may be used: silicon nitride, titanium fried, silicate, norconicum, and composites of these metals and ceramics may also be used.

Note that the sprayed film may be formed on the entire surface of the cavity, or may be formed on a designated portion.

Further, the outer diameter of the micropent piece may be any size, but approximately 3x is appropriate, and the length is preferably approximately 10mm. The diameter of the ventilation hole formed in this micro pent piece is preferably 1+ oz or less, more preferably 0.6 oz or less, from the point of view of narrowing the diameter and shortening the length of the spill, and the lower limit is 0. It would be better to set it as 4 parrots. Furthermore, the number of micro pent pieces is 0.0.
17~0.16 pieces/m, especially sails 017~0.054 pieces/m
d.

The uninvented method for producing a molded product using a polymeric material uses a mold as described above, supplies a polymeric molding material such as a raw tire into the mold (cavity space), and removes the molding material and the molded product. Molding is carried out under desired conditions (temperature, pressure, etc.) according to the type.

In this case, the mold used in the present invention is coated with a thermally sprayed film having fine irregularities, and the molding material is supplied.1. When 1
g. Due to the presence of minute irregularities in the sprayed film, the molding material does not come into close contact with the sprayed film, and a gap is created between the molding material and the sprayed film, albeit for a short time. As a result, the air in the mold (cavity space) diffuses through this gap to the micropent piece, eliminating air pockets and residual air, and preventing poor appearance. (Especially in the case of the mold shown in Figure 1) Also, in the case of the mold shown in Figure 2, air flows through the pipe and diffuses to the micro-pent piece, preventing air pockets and remaining air from forming. be done. On the other hand, the micro pent piece is this L')211. It has the function of discharging the air inside the mold to the outside, and also has the function of narrowing the diameter and shortening the length of spills caused by the flow of molding material during molding, thus causing spills in the molded product. Since the sieve molecules are very thin and short, the trimming step of the spill can be omitted and the appearance will not be affected even if trimming is not performed.As described in detail, the present invention provides sieve molecules with a good appearance. Material molded products can be manufactured efficiently, and especially when used for vulcanization molding of green tires, it simultaneously eliminates the process of applying external liquid to prevent air accumulation and the process of trimming spills, which was previously impossible. In addition, since there is no need to use external liquid, the life of the micro pent piece is greatly extended, and the number of micro pent pieces can be reduced to less than 1/3 of the conventional number. Therefore, from this point of view as well, the appearance of the molded product is improved and visual inspection becomes easier. Therefore, the present invention is particularly effective for manufacturing rubber molded products such as tires.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples, but the invention is not limited to the Examples below.

[Example 1] A nickel-chromium alloy (Mi70 manufactured by Showa Denko) was plasma sprayed onto the tire side part of a 165SR13 tire mold to form a sprayed film of 60 μm. The surface roughness was Ra = 4.0μm''1? After that, the outer diameter was 311J.
I. Place 6 micro vent pieces each with a hole diameter of 0.6 mm on the side of the tire so that their tips are exposed from the sprayed film.
A total of 18 pieces were installed in one row, and a mold as shown in Fig. 1 was obtained.

This tire mold was attached to a 77 [1 curing machine, and a raw tire without any external surface liquid coated was vulcanized.

As a result, the air residue (bear) occurrence rate was less than 5%. In addition, the length of the tire spew was less than 6 cranes, so there was no need for trimming for the appearance.

[Comparative Example 1] The same number of micro vent pieces were attached to a tire mold for 165SR13 at the same positions as in Example 1 without forming a sprayed film.

This tire mold was attached to a vulcanizer *b, and a raw tire whose outer surface was not coated with liquid was vulcanized.

As a result, the bear incidence was approximately 25%.

[Example 2] Outer diameter 3 on the tire side part of the tire mold for 1658R13
m, 6 micro vent pieces with a hole diameter of 0.6 mm, 3 each
A total of 18 rows were installed. Next, a nickel chromium alloy (Showa Denko gMA-70) was plasma sprayed on top of it to form a sprayed film with a surface roughness of 4.0 μm at □Q/1 m, and a mold as shown in Fig. 2 was formed. Obtained.

This tire mold was attached to a Karo curing machine, and a green tire without any external surface coating was vulcanized.

As a result, the bear occurrence rate was less than 5 inches.

In addition, the length of the tire spill was less than 6 mm, so there was no need for trimming in terms of appearance.

[Comparative Example 2] The same micro vent pieces as in Example 1 were placed in 5 rows of 12 pieces each, 6 in total, on the tire side part of the 1653113 River tire mold.
Take 0 pieces and attach 7 pieces.

This tire mold was directly attached to a vulcanizer without forming a sprayed film, and was vulcanized using a green tire without external il [i-liquid"fm".

As a result, the bear occurrence rate was less than 1.0.

[Brief explanation of the drawing]

1 and 20 are cross-sectional views in the tire radial direction showing an example of a tire mold used for carrying out the present invention. l...Mold, 2...Cavity surface, 3...Sprayed film, 4...Micro vent piece, 5...Vent hole.

Claims (1)

[Claims] 1. When a polymer molding material is supplied into a mold and a polymer molded product is produced, a thermal spraying film is applied to the entire or part of the cavity surface of the mold that is in contact with the polymer molding material. 1. A method for producing a molded product using a polymeric material, the method comprising using a mold having a micro-vent piece attached thereto and communicating with the inside of the cavity and the outside of the mold. 2. The method according to claim 1, wherein the micro vent piece is attached so that its tip penetrates through the thermal sprayed film and is exposed from the thermal sprayed film. 3. The method according to claim 1, wherein the micro vent piece is attached so that its tip is covered with a thermally sprayed film. 4. The method according to claim 1, 2 or 3, wherein the polymer molding material is molded without applying an external liquid thereto.