JP4148843B2 - Manufacturing method of foam mold - Google Patents

Description

[0001]
【Technical field】
The present invention relates to a foam molding die manufacturing how made of a thermoplastic resin.
[0002]
[Prior art]
Conventionally, there is a foam molded article obtained by filling pre-expanded particles of a thermoplastic resin into a mold, and heating and heating with a heating medium such as water vapor to cause foaming and fusion.
However, as shown in FIG. 19, a tortoiseshell pattern 92 is formed between the foamed resin particles 90, and this may be conspicuous on the surface 91 of the foamed molded product 9, which may impair the appearance.
In order to deal with such a problem, a technique is disclosed in which an uneven pattern is formed on the surface 91 of the foam molded body 9 to make the turtle shell pattern 92 inconspicuous (see, for example, Patent Documents 1, 2, and 3).
[0003]
[Patent Document 1]
Registered Utility Model No. 3045015 [Patent Document 2]
Registered Utility Model No. 3045016 [Patent Document 3]
Registered Utility Model No. 3045017 [0004]
[Problems to be solved]
However, the above prior art has the following problems.
That is, when manufacturing the mold disclosed in Patent Document 1, it is necessary to separately arrange a face material having an uneven pattern such as a metal net or punching metal on a wooden mold for molding the mold. For this reason, there is a risk of reducing the manufacturing cost and production efficiency of the mold.
Also in the molds disclosed in Patent Documents 2 and 3, when molding a foam molded body, it is necessary to separately arrange a face material having an uneven pattern such as a metal mesh or punching metal. The production cost and production efficiency may be reduced.
[0005]
Things present invention, such conventional been made in view of the problems, seeks to provide a manufacturing how the foam molding die can be inexpensively and molded efficiently with excellent appearance design foam moldings It is.
[0006]
[Means for solving problems]
For convenience of explanation, the reference invention will be described first.
The present invention relates to a foam molding die for molding a foam molded article made of a thermoplastic resin, the foam molding die having an infinite number of uneven patterns on its molding surface. molding die near Ru.
[0007]
Since the molding surface of the upper Symbol foam molding die are innumerable uneven pattern is formed, by molding the expanded molded article using the foam molding mold, the surface of the foam molded article, the molding surface Innumerable uneven patterns corresponding to the uneven patterns can be formed.
Therefore, the turtle shell pattern formed between the foamed resin particles constituting the foamed molded product can be made inconspicuous, and the appearance design of the foamed molded product can be improved.
[0008]
Further, since the uneven pattern in the foam mold is directly formed on the molding surface, the structure of the foam mold can be simplified. Therefore, it is possible to reduce the manufacturing cost and improve the production efficiency of the foaming mold.
In addition, when molding a foamed molded product, there is no need to separately provide a separate member on the mold for attaching the concavo-convex pattern to the foamed molded product. Improvements can be made.
[0009]
As described above, according to this reference invention, it is possible to provide a foam molding die was superior in appearance design foam molded article can be molded well inexpensive and efficient.
[0010]
Next, the present invention will be described.
The present invention relates to a method for producing a foam mold for molding a foam molded article made of a thermoplastic resin.
A surface material composed of a coagulated material and coarse sand having large particles is arranged on the mold surface of the primary mold for sand mold production, and a back surface composed of fine sand having a particle smaller than the coarse sand and the coagulated material on the outside thereof. Place the materials and cure them integrally to create a sand mold,
Next, the foam mold is produced by casting using the sand mold to obtain a foam mold having an infinite number of irregularities on the molding surface (Claim 1 ).
[0011]
In this manufacturing method, a sand mold is produced using a primary mold for creating a sand mold, and a foam molding die is produced using the sand mold. In producing the sand mold, a surface material made of a solidified material and coarse sand having a large particle size is arranged on the mold surface of the primary mold. Thereby, the rough sand is arranged on the mold surface of the sand mold.
[0012]
Therefore, the foam molding die is molded by using a sand mold having a mold surface on which coarse sand is arranged, so that innumerable uneven patterns are formed on the surface of the foam molding die. That is, innumerable uneven patterns are formed on the molding surface of the foam molding die.
Thus, according to this manufacturing method, it is possible to easily obtain a foam molding die having countless uneven patterns on the molding surface.
[0013]
In addition, by forming a foam molded body using the foam molding die, it is possible to form innumerable uneven patterns corresponding to the uneven patterns on the molding surface on the surface of the foam molded body.
Therefore, the turtle shell pattern formed between the foamed resin particles constituting the foamed molded product can be made inconspicuous, and the appearance design of the foamed molded product can be improved.
[0014]
In addition, when molding a foamed molded product, there is no need to separately place a separate member on the mold to add a concavo-convex pattern to the foamed molded product, reducing the manufacturing cost of foamed molded product and improving production efficiency. Can be achieved.
[0015]
As described above, according to the present invention, it is possible to provide an easy-to-manufacture method for producing a foam-molded mold that can form a foam-molded article excellent in appearance design property at low cost and efficiently.
[0016]
As the foam molded article made of a thermoplastic resin obtained by using the foam molding die, there is shall to have a a hexagonal pattern formed between innumerable uneven pattern and the foamed particles on the surface thereof.
[0017]
Since the foamed molded article has numerous concavo-convex patterns on the surface together with the turtle shell pattern, the turtle shell pattern is difficult to recognize in appearance and is inconspicuous. Therefore, it is possible to obtain a foamed molded article excellent in appearance design.
[0018]
As described above, according to the foam molding die obtained by the present invention, it is possible to provide a foam molded article excellent in appearance design.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
The upper Kinetsu thermoplastic resin, for example, may be used polyethylene, polyolefin resins such as polypropylene, or a polystyrene resin.
Moreover, the depth of the concavo-convex pattern can be set to, for example, 0.3 to 3.0 mm.
[0020]
Moreover, it is preferable to provide pores for introducing air for filling the foamed resin particles into the mold and for introducing steam for heating and foaming the foamed resin particles.
The diameter of the pore is preferably 0.3 to 1.5 mm in order to effectively perform the air venting and steam introduction. In addition, the pitch interval of the pores is preferably 5 to 50 mm in order to effectively perform the above air venting and steam introduction.
[0021]
Further, the innumerable uneven pattern is preferably a satin pattern (claim 3).
In this case, a pear ground pattern can be formed on the surface of the foamed molded product, and the turtle shell pattern can be made less noticeable. Therefore, it is possible to obtain a foam molding die capable of molding a foam molded article having further excellent appearance design.
[0022]
Oite the present invention, the primary type can be used, for example gypsum, those made of wood or the like.
In addition, as the solidified material, a material generally used for producing a casting sand mold such as water glass can be used.
[0023]
Further, it is preferable that the coarse sand having an average particle diameter of 0.5 to 5.0 mm (claim 2).
In this case, an uneven pattern with an appropriate size can be formed on the surface of the foamed molded product. Therefore, the turtle shell pattern on the surface of the foam molded article can be made inconspicuous more effectively, and the appearance design can be improved.
When the average particle size of the coarse sand is less than 0.5 mm, the uneven pattern formed on the foamed molded product is too fine, and it may be difficult to make the turtle shell pattern inconspicuous. On the other hand, when the average particle size of the coarse sand exceeds 5.0 mm, the uneven pattern formed on the foamed molded product is too rough, which may impair the appearance of the foamed molded product.
[0024]
Above Symbol myriad of uneven pattern it is, have preferred to be a satin pattern.
In this case, the tortoiseshell pattern formed between the foamed resin particles constituting the foamed molded product can be made less noticeable, and a foamed molded product having a more excellent appearance design can be obtained.
[0025]
【Example】
The foam mold according to the embodiment of the present invention and the manufacturing method thereof will be described with reference to FIGS.
First, the foam molding die 1 to be manufactured in this example is a die for molding a foam molding 2 made of a thermoplastic resin as shown in FIG.
As shown in FIG. 1, the foam molding die 1 has innumerable uneven patterns 13 on the molding surface 11. This countless uneven pattern 13 is a pear pattern.
[0026]
In the production of the above-mentioned foaming mold 1, as shown in FIG. 6, solidified material and coarse sand with large particles are placed on the mold surface 31 of the primary mold 3 for sand mold production as shown in FIG. 5. A surface material 41 is arranged. Further, as shown in FIG. 7, a back material 42 made of fine sand having a smaller particle size than the coarse sand and a solidified material is disposed on the outside thereof. And these are hardened integrally and the sand mold 4 is produced.
[0027]
Next, as shown in FIG. 10, by casting using the sand mold 4, as shown in FIG. 1, as shown in FIG. 1, the foaming mold 1 having innumerable uneven patterns 13 on the molding surface 11 is obtained.
The coarse sand has an average particle size of 0.5 to 5.0 mm. The fine sand has an average particle size of 0.1 to 0.2 mm.
[0028]
A method for manufacturing the foam molding die 1 will be described in detail below.
In manufacturing the lower mold 1a of the foam molding die 1, first, as shown in FIG. 3, a wooden mold 5a corresponding to the shape of the molding surface 11 of the lower mold 1a to be obtained is prepared. 4 and 5, a primary mold 3 is obtained by forming a mold surface 31 having the same shape as the molding surface 11 of the lower mold 1a on the plaster using the wooden mold 5a. Next, as shown in FIG. 6, the surface material 41 is disposed on the mold surface 31 of the primary mold 3.
[0029]
Next, as shown in FIG. 7, the back material 42 is disposed on the surface material 41.
Then, the top material 4b of the sand mold 4 is obtained by integrally curing the surface material 41 and the back material 42 in the primary mold 3.
[0030]
In producing the lower mold 4a of the sand mold 4, a wooden mold 50a (FIG. 8) having a shape corresponding to the mold surface 43 (FIG. 9) to be formed on the lower mold 4a is prepared. Then, the lower mold 4a of the sand mold 4 shown in FIG. 9 is produced using the wooden mold 50a. For the lower mold 4a, the same material as the back material 42 of the upper mold 4b is used.
[0031]
As shown in FIG. 10, the produced sand mold 4 has a lower mold 4a and an upper mold 4b which are overlapped to form a cavity 44. A metal such as aluminum or iron is injected into the cavity 44, and a foam molding mold is formed. 1 lower mold 1a is cast.
As a result, as shown in FIG. 1, a pear pattern (uneven pattern 13) is formed on the molding surface 11 of the lower mold 1a of the foam molding die 1.
[0032]
In manufacturing the upper mold 1b of the foam molding die 1, as shown in FIG. 11, a wooden mold 5b corresponding to the shape of the molding surface 11 of the upper mold 1b to be obtained is prepared. Then, as shown in FIG. 12, a mold surface 31 having the same shape as the molding surface 11 of the upper mold 1b is formed on gypsum using the wooden mold 5b to produce a primary mold 30.
Next, as shown in FIG. 13, the surface material 41 and the back material 42 are sequentially arranged on the mold surface 31 of the primary mold 30, and these are integrally cured, so that the upper mold 40b of the sand mold 40 shown in FIG. Is made.
[0033]
Further, as shown in FIGS. 14 and 15, the lower mold 40a of the sand mold 40 is produced using the wooden mold 50b. The lower mold 40a is made of the same material as the back material 42 of the upper mold 40b.
A cavity 44 is formed by superposing the lower mold 40a and the upper mold 40b of the produced sand mold 40 as shown in FIG. Then, as shown in FIG. 17, molten metal such as aluminum or iron is poured into the cavity 44 to cast the upper mold 1 b of the foam molding die 1.
As a result, as shown in FIG. 1, a pear pattern (uneven pattern 13) is formed on the molding surface 11 of the upper mold 1b of the foam molding die 1 as shown in FIG.
The foaming mold was provided with pores having a pitch of 25 mm and a pore diameter of 1 mm (not shown) for venting air and introducing steam.
[0034]
In this way, the lower mold 1a and the upper mold 1b of the foaming mold 1 as shown in FIG. 1 are produced.
Then, pre-expanded particles of thermoplastic resin such as polyethylene are filled in the foam molding die 1 and heated, foamed, and fused with a heating medium such as water vapor to form the foam molded body 2. As a result, as shown in FIG. 2, a pear ground pattern (uneven pattern 23) is formed on the surface 21 of the foamed molded body 2 together with the turtle shell pattern 22.
[0035]
Next, the effect of this example will be described.
As shown in FIG. 1, innumerable uneven patterns 13 are formed on the molding surface 11 of the foam molding die 1. Therefore, by forming the foam molded body 2 using the foam molding die 1, the surface 21 of the foam molded body 2 has innumerable concavo-convex patterns 23 corresponding to the concavo-convex patterns 13 of the molding surface 11, that is, pears. A ground pattern can be formed.
Therefore, as shown in FIG. 18, the turtle shell pattern 22 formed between the foamed resin particles 20 constituting the foamed molded body 2 can be made inconspicuous, and the appearance design of the foamed molded body 2 can be improved. Can do.
[0036]
Moreover, since the uneven | corrugated pattern 13 in the said foaming mold 1 is directly formed in the molding surface 11, the structure of the foaming mold 1 can be simplified. Therefore, the manufacturing cost of the foam mold 1 can be reduced and the production efficiency can be improved.
Further, when molding the foam molded body 2, it is not necessary to separately provide another member for attaching the uneven pattern 23 to the foam molded body 2, so that the manufacturing cost of the foam molded body 2 can be reduced. , The production efficiency can be improved.
[0037]
Moreover, since the rough sand which comprises the said surface material 41 is 0.5-5.0 mm in average particle diameter, the uneven | corrugated pattern 23 of a moderate magnitude | size can be formed in the surface 21 of the foaming molding 2. FIG. Therefore, the turtle shell pattern 22 on the surface 21 of the foam molded body 2 can be made inconspicuous more effectively, and the appearance design can be improved.
[0038]
As described above, according to this example, a foam molding die capable of forming a foam molded article excellent in appearance design property inexpensively and efficiently, a manufacturing method thereof, and a foam molding molded by the foam molding die. The body can be provided.
[0039]
(Experimental example)
A foam-molded article was produced using the foam-molding die shown in the above examples.
That is, polypropylene pre-expanded particles having a bulk density of 18 g / L (manufactured by Mitsubishi Chemical Foam Plastic Co., Ltd., trade name: EP Pole) were compressed and filled as foamed resin particles in a foaming mold at a filling pressure of 0.15 MPa.
Subsequently, foam molding was performed under the conditions of a heating water vapor pressure of 0.3 MPa, a heating time of 30 seconds, and a cooling time of 60 seconds. The molded article magnification of the obtained foamed molded product was 30 times. And as shown in FIG. 18 of the said Example, many pear ground patterns (uneven | corrugated pattern 23) and the turtle shell pattern 22 were formed on the surface of the foaming molding. However, the presence of the turtle shell pattern 22 is not noticeable due to the pear pattern, and the design of the surface of the foamed molded product has been improved.
On the other hand, as a comparative example, a foamed molded product was produced under the same conditions as above using a conventional foamed mold in which the uneven pattern was not formed.
As a result, as shown in FIG. 19, the pear ground pattern 92 was very conspicuous because the pear pattern was not formed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a foam mold according to an embodiment.
FIG. 2 is a cross-sectional view of a foamed molded product in an example.
FIG. 3 is a cross-sectional view of a wooden pattern in the embodiment.
FIG. 4 is an explanatory diagram of a process of forming a primary mold in an example.
FIG. 5 is a cross-sectional view of a primary mold in an embodiment.
FIG. 6 is a cross-sectional view showing a state in which a surface material is arranged on a primary mold in the embodiment.
FIG. 7 is a cross-sectional view illustrating a state in which a back material is disposed on a primary mold in the embodiment.
FIG. 8 is a cross-sectional view of a wooden shape in the embodiment.
FIG. 9 is a cross-sectional view of a lower sand mold in an embodiment.
FIG. 10 is a cross-sectional view of a sand mold in an example.
FIG. 11 is a cross-sectional view of a wooden shape in an example.
FIG. 12 is an explanatory diagram of a process of forming a primary mold in an example.
FIG. 13 is a cross-sectional view showing a state in which the surface material and the back material are arranged in the primary mold in the embodiment.
FIG. 14 is an explanatory diagram of a process of forming a lower mold of a sand mold in an example.
FIG. 15 is a cross-sectional view of a lower sand mold according to an embodiment.
FIG. 16 is a cross-sectional view of a sand mold in an example.
FIG. 17 is an explanatory diagram of a process of molding the upper mold of the foam molding die in the example.
FIG. 18 is an explanatory view of the surface of a foam molded article in an example.
FIG. 19 is an explanatory view of the surface of a foam molded article in a conventional example.
[Explanation of symbols]
1. . . Foam mold,
1a. . . Lower mold,
1b. . . Upper mold,
11. . . Molding surface,
13. . . Uneven pattern,
2. . . Foam molding,
21. . . surface,
22. . . Turtle shell pattern,
23. . . Uneven pattern,
3,30. . . Primary type,
4,40. . . Sand mold,
41. . . Surface material,
42. . . Backing material,

Claims (3)

In the method for producing a foam mold for molding a foam molded article made of a thermoplastic resin,
  A surface material comprising a solidified material and coarse sand having large particles is arranged on the mold surface of the primary mold for sand mold production, and a back surface comprising fine sand and solidified material having smaller particles than the coarse sand on the outside thereof. Place the materials and cure them integrally to create a sand mold,
  Next, a foam molding die having a myriad of concavo-convex patterns on the molding surface is obtained by casting using the sand mold. 2. The method for producing a foam molding die according to claim 1, wherein the coarse sand has an average particle size of 0.5 to 5.0 mm. 3. The method for producing a foam mold according to claim 1, wherein the infinite number of uneven patterns is a pear pattern.

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