JP3592133B2 - Core vent used for foam resin molding equipment - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a core vent used for a foamed resin molding device.
[0002]
2. Description of the Related Art
Conventionally, a foaming resin molding apparatus fills foaming thermoplastic resin particles into a mold cavity of a molding die, heats and expands the particles using steam as a heating medium, and heat-fuses the particles together to form the foam. As a means for forming a steam hole to be mounted on a mold assembled in a molding apparatus, a method using a core vent is generally used. This core vent is inexpensive and suitable for mass production. Handling at the time of assembling into a mold is also easy, and is currently used regularly.
[0003]
The role of the core vent is as follows: (1) The air at the time of filling is released to increase the filling efficiency of the raw material. To prevent poor filling and shorten the filling time. {Circle around (2)} This is an entrance for introducing steam in the heating step and for introducing steam into the foamed particles. {Circle around (3)} This is for discharging air in the vacuum cooling process and discharging water therefrom.
As a mounting method for use, a fitting method in which a through hole is formed in a mold made of an aluminum alloy and press-fitted therein is generally used.
[0004]
However, also in the case of the core vent 10 of FIG. 7 in which the through groove 11 is a drill hole type or the core vent 10 in the case of FIG. 8 of a slit type, in the case of the core vent having a shorter overall length than the mold thickness, as shown in FIG. When the cooling water W accumulates and the molded product is taken out from the mold, there is a disadvantage that water adheres to the molded product.
The inventor of Japanese Utility Model Publication No. 61-194 was first devised in order to eliminate the drawback that water accumulates on the back of the mold. According to this invention, when the end surface of the column for the steam hole having a longer overall length than the mold thickness is flush with the inner surface of the mold, the columnar portion on the other end surface side protrudes to the outer surface of the mold, and Since a cylindrical lid having a gap provided between the end face and the outer periphery is attached, water is prevented from entering. However, in this invention, the cylindrical lid is assembled from two or more parts, and the assembly cost and the manufacturing cost are high, and the cylindrical lid is separated due to the thermal expansion of the mold and the foaming pressure of the resin during use. There was a problem that it was removed.
[0005]
Japanese Utility Model Publication No. 3-002727 discloses a steam passage structure in which a columnar body having a concave groove formed on a side surface is buried in a through-hole of a mold and opened inside and outside the mold. Since the concave groove opening on the end face of the columnar body on the outside of the mold is exposed, water on the end face cannot be prevented from entering the mold, and improvement has been demanded.
Therefore, in the present invention, a core vent that eliminates the inconvenience of combining two or more components as in the core vent according to the prior art, simplifies the structure, and prevents water accumulated on the back of the mold from entering the mold. The present invention has been completed after intensive studies for the purpose of providing.
[0006]
[Means for Solving the Problems]
As the core vent according to the present invention which can achieve the above-mentioned object, as described in claim 1, a solid columnar body serving as a core vent inserted into a through-hole of a molding die has a thickness of the die. It is formed longer than the above, one end surface of both end surfaces of the columnar body is located on the mold inner surface side, the other end surface is protruded from the mold outer surface side, and a part of the side surface portion is the mold. It is exposed to the outside, and the solid columnar body is open from one end surface on the mold inner surface side to the side surface exposed on the mold outer surface side, but does not reach the other end surface. The slits are cut to form through-grooves to communicate the inside and outside of the mold.
[0007]
In the core vent according to the first aspect, a through groove for communicating the inside and the outside of the mold is opened from one end surface on the inner surface side of the mold to a side surface portion exposed on the outer surface side of the mold. Since the core vent of the present invention is formed to a length that does not reach the end surface, water on the back surface of the mold does not enter the mold, and does not adhere to the molded product when the molded product is taken out. It is possible to obtain a molded article with extremely low. The material of the core vent is generally a metal such as brass or aluminum alloy, but any metal or resin can be used as long as the material does not deteriorate or rust. However, since there is a case where the foamed resin adheres to the resin-made molded product, a coated product having no adhesion to the foamed resin is preferable. The outer diameter of the core vent is selected depending on the shape of the mold, the size of the portion where the through hole is formed, and the like, and is not particularly limited, but is generally 10 mmφ, and a fine portion having a diameter of 5 to 8 mmφ is used. The width of the groove of the core vent is 0.1 to 0.5 mm. A wider one is more suitable for molding because the inflow increases as described above, but it is not necessary that the resin is too wide because the resin is pinched and adhered and a molded article is scratched. The depth of the groove needs to be equal to or greater than the thickness of the mold because the groove needs to be opened to the side surface exposed on the outer surface of the mold. Generally, when the mold thickness is 8 mm, the groove depth is 10 mm or more, and preferably about 10 to 20 mm. In any case, a core vent having a groove depth corresponding to the thickness of the mold may be manufactured and used.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be sequentially described below with reference to the drawings.
FIG. 1A is a perspective view showing a first embodiment of a columnar body 1 serving as a core vent according to the present invention, and FIG. 1B is a side view seen from one end face 2 side, and FIG. 2) and 3) are cross-sectional views showing a state in which each of the through-holes 21 extending over the entire molding die 20 of the foamed resin molding apparatus is fitted by press fitting or the like, and a partial cross-sectional view. And the columnar body 1 is formed to be longer than the thickness T of the mold 22 of the core vent attachment portion.
[0009]
One end surface 2 of both end surfaces 2 and 3 of the columnar body 1 is positioned so as to face the cavity C which is the inner surface 23 side of the mold 22, and the other end surface 3 is located on the outer surface 24 side of the mold 22. It is positioned so as to protrude, and some side surfaces 5 are exposed outside the mold. The columnar body 1 is formed with a through-groove 4 for communicating the inside and outside of the mold 22. The through-groove 4 is formed from the one end face 2 on the inner surface 23 side of the mold 22 to the outer surface 24 of the mold 22. Although it is open to the side surface portion 25 exposed to the side, it is formed to have a length that does not reach the other end surface 3, and the other end surface 3 has no through groove 4 and is not opened. Become. In the figure, reference numeral 30 denotes a molded body molded in the cavity C. 40 is a raw material filling device.
[0010]
By using the above-described columnar body 1 as a core vent, the water pool W adheres to the other end surface 3 of the columnar body 1 on the outer surface 24 side of the mold 22, but since the through groove 4 is not formed in the other end surface 3, In addition, water does not enter into the mold 22, and it is possible to obtain a molded product having extremely little water wettability without adhering to the molded product when removing the molded product.
[0011]
In addition, as the passage groove 4 in the columnar body 1 serving as a core vent, as shown in FIGS. 4 and 5, in addition to the passage groove 4 which does not completely penetrate from the side surface portion 5 to the opposite side surface portion 5, as shown in FIG. It can be implemented in a form penetrating into the portion 5 and crossing the passage groove 4 vertically and horizontally.
Next, specific examples will be described below.
〔Example〕
In the form shown in FIG. 1, a core vent made of brass having a cylindrical shape with an outer diameter of 10 mm and a total length of 15 mm and a slit having a groove width of 0.2 mm and a groove depth of 12 mm was cut. The core vent was attached at a pitch of 30 mm to a mold having an outer diameter of 300 × 300 mm and a thickness of 20 mm and a mold thickness of 8 mm (a through hole of 9.8 to 9.9 mmφ was opened).
[0012]
This mold was assembled in a foamed resin molding machine ACE-12QS (manufactured by Sekisui Koki) to carry out molding.
As the foaming resin for molding, foamed particles having a bulk density of 0.016 g / cm ³ and an average particle diameter of about 4 mm obtained by prefoaming expandable polystyrene beads were used.
Molding conditions were 5 seconds for normal filling, 2 seconds for evacuation of the mold, 4 seconds for heating, 3 seconds for reverse heating, 8 seconds for both sides heating at 0.7 kg / cm ² , 5 seconds for water cooling, 4 seconds for drainage, vacuum The cooling was performed at -55 cmHg for 40 seconds, and the total cycle was 82 seconds. Molding was possible without changing ordinary molding conditions, and a foam molded article having a density of 0.0177 g / cm ³ was obtained.
{Circle around (1)} Conventionally known 5 mm-length core vents of the conventional type with slits, conventionally known cylindrical vents with a total length of 10 mm by drilling through holes, and the above-described 15 mm-length core vents according to FIG. Comparing the moisture attached to the molded body when foam molding is performed by attaching to an 8 mm mold,
<Moisture attached>
Normal core vent with a total length of 5 mm 11.3% (3.6 g)
5.6% (1.8 g) through hole drilling type core vent with a total length of 10 mm
2.5% (0.8 g) of the core vent of the present invention with a total length of 15 mm
{Circle around (2)} When the foamed molded article obtained was dried in an atmosphere of 60 ° C., it took 4 hours when molded with a cylindrical vent hole core vent, but 1.5 hours when molded with the core vent of the present invention. The time was greatly shortened, and a remarkable improvement was obtained, in which the steam of the drying heat source was reduced by 60%.
[0013]
【The invention's effect】
The core vent according to the present invention is suitable for preventing moisture adhering to the outer surface of the mold from entering the mold, and can greatly reduce the moisture adhering from the vicinity of the core vent to the foam molded article. It can be manufactured as a single item, there is no risk of separation during use as in the assembly of multiple parts, there is no assembly cost, and it is a simple product with a groove formed in the columnar body, so manufacturing costs etc. The advantage of low cost is great.
[Brief description of the drawings]
1A is a perspective view showing a core vent of the present invention, FIG. 1B is a side view, and FIG. 1C is a sectional view.
FIG. 2 is a schematic cross-sectional view of the entire mold showing a use state of the core vent of the present invention.
FIG. 3 is a partially enlarged sectional view of FIG. 2;
FIG. 4A is a side view showing a modified example of the shape of the passage, and FIG. 4B is a sectional view.
FIG. 5A is a side view showing a modified example of the passage groove form, and FIG. 5B is a cross-sectional view.
FIG. 6 is a side view showing a modified example of the groove configuration.
FIG. 7 (a) is a side view showing a conventional drilled hole type core vent, and FIG. 7 (b) is a sectional view.
8 (a) is a side view showing a conventional slit type core vent, and FIG. 8 (b) is a sectional view.
FIG. 9 is a partially enlarged sectional view showing a use state of a conventional product.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Columnar body which becomes a core vent 2 One end surface 3 The other end surface 4 Through-groove 5 Side surface part 20 Whole molding die 21 Through hole 22 Mold of core vent attachment part 23 Mold inner surface 24 Mold outer surface C Cavity 30 Molded body

Claims (1)

A solid columnar body serving as a core vent fitted into the through hole of the molding die is formed longer than the mold thickness, and one end surface of both end surfaces of the columnar body is positioned on the mold inner surface side, Yes and the other end face is positioned to protrude from the mold the outer surface side, a part of the side surface portion is Yes exposed outside the mold, from one end face to the middle pillar of the real in the mold inner surface, the mold outer surface A foamed resin, which is open to the side part exposed to the side, but cuts a slit having a length not reaching the other end face to form a through groove and communicates the inside and outside of the mold. Core vent used for molding equipment.

Images