JPH1190989A - Manufacture of hard foam molding with protrusion and recess surface, and tray - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a dense hard foam molding having a protrusion and recess surface of a low cost even in the case of small quantity and multikind in a short delivery date. SOLUTION: A hard foam molding having a desired protrusion and recess surface is obtained by giving the desired surface to a smooth surface of a dense, homogeneous light-weight hard foam having 50 to 90% of foam having a size of 200 μm or less to entire volume, a density of 0.1 to 0.5 g/cm<2> and a compression strength of 1 to 10 MPa, and pressing a resin male mold having a compression strength of 10 times or more as large as the hard foam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a rigid foam molded article having an uneven surface and a tray. More specifically, a method for producing a rigid foam molded article that imparts a desired uneven surface to a smooth surface of a dense, homogeneous, lightweight rigid foam material; and a small-sized assembly line made of the rigid foam molded article obtained by this production method. The present invention relates to a component storage tray.

[0002]

2. Description of the Related Art Conventionally, as a method of obtaining a molded article of a dense rigid foam material having a desired uneven surface, a method of cutting the rigid foam material itself for each single article, or casting or injection molding into a mold. Methods and the like are known.

[0003]

However, in the case of a molded product such as a small component storage tray for an assembly line used in a factory for manufacturing electric appliances, office equipment, etc., there are cases where a small number of various types of molded products are required. In order to manufacture a large number of low-volume, multi-product molded products, it takes a long time to perform a cutting process and a mold for each material, and thus there is a problem in that the construction period is increased and the cost is increased.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that press molding of a specific lightweight rigid foam material is effective in improving the above problems, and The invention has been reached.

That is, the present invention provides a method for producing a rigid foam molded article having an uneven surface characterized by pressing a male mold (B) made of a resin described below on a smooth surface of the following rigid foam (A); A small component storage tray for an assembly line, comprising a rigid foam molded product obtained by a manufacturing method. Rigid foam (A): Smooth surface, diameter 200μ
m to 50% to 90% of the total volume, the density is 0.1 to 0.5 g / cm ³ , and the compressive strength is 1 to
Dense, homogeneous, lightweight rigid foam of 10 MPa. Resin male mold (B): A resin male mold having a compressive strength ten times or more that of (A) and capable of imparting a desired uneven surface shape to the smooth surface of (A).

[0006]

According to the production method of the present invention, the rigid foam (A) is a foam containing 50 to 90% of the total volume of cells and having a compressive strength of 1 to 10 MPa. B) has a compressive strength of at least 10 times that of (A), and therefore, by pressing the male mold (B) capable of imparting a desired uneven surface shape onto the smooth surface of (A), The foam structure in the portion (A) where the convex portion contacts is irreversibly compressed, and a desired uneven surface shape is imparted to (A).
Since the rigid foam (A) is a dense and homogeneous foam having a compressive strength of 1 to 10 MPa, there is no material destruction around the pressed area, and the uneven surface applied is dense and uniform, and the dimensional accuracy is good. It is.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION As the rigid foam (A),
For example, a polyurethane foam obtained by reacting a bifunctional or higher polyether polyol with a polyisocyanate or an isocyanate group-containing prepolymer in the presence of a catalyst, a foaming agent and a foam stabilizer; a bisphenol A type epoxy resin and an amine curing agent; In the presence of catalyst, foaming agent, foam stabilizer,
Epoxy foams obtained by the reaction; polystyrene foam beads obtained by heating and foaming polystyrene in the presence of a foaming agent; and the like can be used.

The rigid foam (A) has a density of 0.1 to
0.5 g / cm ³ , preferably 0.2 to 0.4 g / cm ³
It is. If it is less than 0.1 g / cm ³ , there is a problem that the strength is low and the obtained molded product is fragile and fragile.
If it is larger than 0.5 g / cm ³ , the amount of air bubbles contained is small, so that the convex portion of the male mold (B) cannot compress the inside of (A) during the pressing and advance at the desired depth. However, there is a problem that the concave portion cannot be formed.

The compression strength of the rigid foam (A) is from 1 to 1.
0 MPa, preferably 1.5 to 8.0 MPa. 1
When the pressure is less than MPa, the strength is not enough.
There is a problem that the whole is deformed. If it exceeds 10 MPa, the strength is too large, so that the convex portion of the male mold (B) does not completely enter the inside of (A) at the time of pressing, and a concave portion having a desired depth cannot be formed. In addition, there is a problem that if pressure is forcibly applied, the entire structure (A) is deformed.

The diameter of the cells contained in the rigid foam (A) is 200 μm or less, preferably 150 μm or less. When the thickness exceeds 200 μm, there is a problem that the grain is coarse and the appearance of the obtained molded product is poor, and there is a problem that it is difficult to apply when painting.

The cells contained in the rigid foam (A) are as follows:
It is 50 to 90%, preferably 70 to 85%, based on the total volume. If it is less than 50%, there are few bubbles, so that the convex portion of the male mold (B) cannot compress the inside of (A) during the pressing, and cannot proceed to form a concave portion having a desired depth. There's a problem. If it exceeds 90%, there is a problem that the obtained molded product is fragile and fragile.

As (A), a rigid urethane foam formed by a mechanical froth foaming method is most preferable because it contains fine bubbles uniformly, and is dense, lightweight and homogeneous.

In the rigid foam (A), the bubbles in the range not exceeding 70%, preferably in the range not exceeding 50% of the total volume of the cells contained in the rigid foam (A) may be the cells contained in the fine hollow spheres. Good. The rigid foam (A) containing the micro hollow spheres has a feature that it has higher strength and is denser than that of the same foam not containing the micro hollow spheres. However, if this sphere exceeds 70% of the total volume of the bubbles, the convex portion of the male mold (B) cannot break down the material inside (A) during pressing, so that it cannot proceed, and There is a problem that a concave portion cannot be formed.

As the material of the male mold (B), plastics, rigid foamed plastics, reinforced plastics, etc. can be used. Rigid foam plastics selected from foams are preferable because they have good cutting workability and can easily be molded with high precision.

In the method of the present invention, a press machine that can be used at the time of pressing is exemplified. When two parallel flat plates approach each other, a pressure is applied to a material sandwiched between the flat plates, and an arbitrary distance is applied. A mechanism that can stop the approach of the flat plate and can apply a pressure of 1 MPa or more can be used. As an example of a pressing method, (B) is placed on (A) placed on a surface plate such that the male mold (B) is in contact with the shape imparting surface of the rigid foam (A), or (A) is Using a vertical press that can be pressed by placing the platen and / or the roof close to it after placing it on the platen (B), positioning of the material is simple. preferable. After imparting an uneven surface shape to the rigid foam (A), cutting, paper polishing,
Post-treatment such as painting may be performed.

The rigid foam molded product having an uneven surface obtained by the method of the present invention is used for various storage trays such as a small component storage tray for an assembly line, a decorative board having an uneven surface, a panel having an uneven surface, and the like. is there. For example, in order to manufacture various storage trays such as a small component storage tray for an assembly line, the resin male die (B) can be provided with a surface shape of a tray having at least one recess capable of storing small components. By using the method, the small component storage tray can be manufactured by the manufacturing method of the present invention.

[0017]

EXAMPLES The present invention will be further described with reference to examples below, but the present invention is not limited to these examples. Example 1 Sun module No. 1 which is a urethane syntactic foam having a density of 0.60 g / cm ³ and a compressive strength of 26 MPa
[Sanyo Chemical Industry Co., Ltd.] 100 mm long x 100 m wide
The surface of a flat plate of mx 50 mm in thickness was NC-cut, and Fig. 1
As shown in the figure, height 9.5 mm × width 9.5 mm × height 5.
A male mold in which four 0 mm convex shapes were arranged in a lattice was prepared.
In FIG. 1, 1 is a male type, and 2 is an inverted surface of the shape of the storage tray. Density 0.22g / cm ³ , compressive strength 1.6M
Sun module ML [manufactured by Sanyo Chemical Industries, Ltd.] which is a mechanical floss foamed rigid urethane foam of Pa.
A flat plate having a size of 00 mm x 100 mm x 50 mm in thickness was converted to a Sindho SF-type hydraulic press [Shinto Metal Industry Co., Ltd.]
On the platen. The male mold was in contact with the flat plate, and the male mold was placed on the flat plate of the Sun module ML such that the length and width of the male mold coincided with the length and width of the flat plate. After the top plate was lowered and the top plate hit the male mold, the male mold was pressed until the convex portion of the male mold entered the flat plate and became invisible. Maximum press pressure is 5.5MP
a. FIG. 2 is a longitudinal sectional view showing a process of giving a shape. In FIG. 2, reference numeral 3 denotes a sun module ML flat plate, and reference numeral 4 denotes a storage tray. FIG. 3 is a perspective view showing the storage tray (4) obtained.
Twenty storage trays in which recesses of 10.0 mm long × 10.0 mm wide × 5.0 mm deep were arranged in a grid were manufactured.

Example 2 Epoxy syntactic foam having a density of 0.70 g / cm ³ and a compressive strength of 80 MPa), length 300 mm × width 300
The surface of a flat plate having a thickness of 50 mm and a thickness of 50 mm was subjected to NC cutting to prepare a male die having a columnar shape having a diameter of 10.0 mm and a height of 5.0 mm arranged in a lattice. At this time, the distance between cylinder centers is 2
0.0 mm. Sun module MH (Sanyo Chemical Industries, Ltd.) which is a mechanical floss foamed hard urethane foam having a density of 0.36 g / cm ³ and a compressive strength of 7.5 MPa
Was pressed at a pressure of 9.5 MPa on the surface of 50 flat plates having a length of 300 mm x a width of 300 mm x a thickness of 50 mm. Fifty storage trays in which concave portions having a diameter of 10.5 mm and a depth of 5.0 mm were arranged in a grid were manufactured.

Comparative Example 1 The same shape as the male type described in Example 1 and a compressive strength of 150 M
An aluminum male mold of Pa was prepared. Density 0.55g / c
The male mold was pressed at a pressure of 15 Pa onto the surface of a flat plate having a length of 100 mm × a width of 100 mm × a thickness of 50 mm of a mechanical froth foamed rigid urethane foam having an m ³ and a compressive strength of 12 MPa. The shape of the male mold was not correctly inverted on the surface of the rigid urethane foam, and the concave portion and its periphery were broken.

Comparative Example 2 A male mold having the same shape as the male mold described in Example 1 was prepared using an epoxy syntactic foam having a density of 0.70 g / cm ³ and a compressive strength of 65 MPa. The male mold was pressed against the MH at a pressure of 9.5 MPa. In the first press, the corners of the male projections were rounded, and a plurality of storage trays could not be manufactured.

[0021]

【The invention's effect】

(1) According to the method of the present invention, by pressing a male mold made of resin on a smooth surface of a rigid foam, the foam structure is irreversibly compressed, and a desired uneven shape is imparted to the rigid foam surface, There is no material destruction around the pressed area,
The concavo-convex surface provided is dense and homogeneous, and has good dimensional accuracy. (2) The method of the present invention is to improve the problems of the conventional cutting method for each single product and casting or injection molding methods. The use of this male mold makes it possible to easily impart an uneven surface shape to the rigid foam simply by pressing, thereby shortening the construction period and enabling small-quantity production of other types. (3) Therefore, a molded article having a cheap and lightweight, dense and concave surface can be manufactured with a short delivery time by the method of the present invention. Since the method of the present invention exhibits these effects, a rigid foam molded article molded into a desired uneven surface shape for each application is
It is useful as various storage trays, such as small component storage trays for assembly lines, decorative boards, panels, and the like.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a resin-made male mold capable of giving the shape of a storage tray.

FIG. 2 is a longitudinal sectional view showing processes before, during, and after pressing according to the method of the present invention.

FIG. 3 is a perspective view showing an example of a storage tray obtained by the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Male type 2 Inversion surface 3 Rigid foam flat plate 4 Storage tray

Claims (6)

[Claims] 1. A method for producing a rigid foam molded article having an uneven surface, characterized by pressing a male mold (B) made of the following resin on a smooth surface of the following rigid foam (A). Rigid foam (A): has a smooth surface, contains 50 to 90% of cells having a diameter of 200 µm or less based on the whole volume, and has a density of 0.
1 to 0.5 g / cm ³ and compressive strength of 1 to 10MP
A dense, homogeneous, lightweight rigid foam of a. Resin male mold (B): 10 times or more the compressive strength of (A), (A)
A resin-made male mold capable of imparting a desired uneven surface shape to a smooth surface. 2. The rigid foam (A) is a rigid urethane foam formed by a mechanical froth foaming method.
Production method described in 1. 3. The method according to claim 1, wherein a part of the bubbles contained in the rigid foam (A) are bubbles in the micro hollow sphere. 4. The method according to claim 1, wherein the material of the resin mold (B) is a rigid foamed plastic selected from a rigid urethane foam, a urethane syntactic foam or an epoxy syntactic foam by a mechanical froth foaming method. Or the production method described. 5. The method according to claim 1, wherein the material of the resin-made male mold (B) is a hard foamed plastic, and a part of the bubbles contained in (B) are bubbles in a minute hollow sphere. Production method as described. 6. A small component storage tray for an assembly line, comprising a rigid foam molded product obtained by the production method according to claim 1.