JPH065159Y2 - Polystyrene foam molding - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polystyrene foam molding used as a cushioning material for packaging and a surface drainage material.

[0002]

2. Description of the Related Art In order to protect a packaged product from an external impact, various forms of foam such as an inner box-shaped product made of expanded polystyrene having a cushioning property and a product in which a foam is bonded to a cardboard paper are used. A molded body made of synthetic resin is used.

The molded product has a particle size of 1.8 obtained by pre-expanding expandable polystyrene particles containing a swelling agent such as butane or pentane as a molding material with steam.
Using ~ 5 cm spherical pre-expanded polystyrene beads,
The beads are filled in a cavity of a mold having a large number of steam holes or slits, and then 1 is placed in the cavity.
Introduce steam at 0 to 130 ° C to heat the beads,
It is obtained by fusing beads together and completing foaming.

[0004]

The foamed synthetic resin molded body thus obtained has almost no voids between the fused beads and has a bulk density (0.026 to
Since 0.2 g / cm ³⁾ is that there is no great difference that polystyrene beads during the pre-expanded (0.025~0.2g / cm ^3), very costly in quantitative terms of material needed for molding However, there is a problem in that it cannot be used as a surface drainage material.

The present invention has been made in view of the above points, and an object of the present invention is to mold an extruded chip made of a polystyrene foam having the same non-spherical shape and to have a bulk density of 0.
It is an object to provide a polystyrene foam molded article which is as small as 005 to 0.1 g / cm ³ , has voids, and is improved so that it can be used as a surface drainage material.

[0006]

In order to achieve the above object, a polystyrene foam molded article, which is a feature of the present invention, is made of polystyrene foam and has the same non-spherical shape with the longest portion having a length of 2 cm or more. It is an in-mold foam molded article with a large number of extruded chips, and the voids 3 exist between the chips due to fusion of the surfaces of these extruded chips, and the void ratio is 5 to 40% of the volume. Is configured to be.

[0007]

【Example】

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. As shown in FIGS. 1 to 3, the same non-spherical shape formed of polystyrene foam having a longest length L of 2 cm or more. 1. An in-mold foam molded article 1 comprising a large number of extrusion-molded chips 1a each having a shape, wherein the fusion of the surfaces of these extrusion-molded chips 1a causes a void 2 to exist between the chips 1a, and the void ratio is It is configured to be 5 to 40% of the total volume of the inner foam molding 1.

If the porosity of the in-mold foam molding 1 is 5% or less, it cannot function as a drainage material, and if it is 40% or more, the strength is insufficient. The extruded chips 1a are obtained by a molding method described later, and in addition to the saddle shape shown in FIG. 3, extruded chips 1b deformed by being extruded into a strand shape, and curved balls shown in FIG. Deformed into a shape 1c, FIG. 6
It may be a ring-shaped member 1d or the like. The length L of the longest portion is 5 times or more the wall thickness t (see FIGS. 3 and 6).

Next, a production example of the polystyrene foam molded article will be described in detail. First, referring to FIG. 7, a method of molding the extrusion molded chip 1a formed of polystyrene foam will be described. A mixture of 98 parts of polystyrene and 2 parts of calcium silicate that is a nucleating agent is supplied to the first extruder 11. This mixture was heated at 230 ° C. and 150 kg / cm ² G
Melt kneading under the conditions of. Then, butane 12
Then, the mixture is pressed at 160 kg / cm ² G to produce a melt-kneaded product containing butane at a ratio of 6%.

The melt-kneaded product is sent to the second extruder 13 to be mixed uniformly and cooled to 120 ° C.
Then, the melt-kneaded product is extruded into a columnar shape in water through a die 14 having a circular orifice with a diameter of 6 mm to obtain an expandable polystyrene columnar material 15. At a stage (100 ° C.) in which the extruded expandable polystyrene columnar material 15 maintains the softened state, the pair of nip rolls 1
After being crushed with Nos. 6 and 16 to make the cross-sectional shape into an elliptical shape, it is cut into individual pieces with a cutter 17 at right angles to the extrusion direction to obtain thin cut pieces 18.

Then, the cut object 18 is deformed by the contracting stress and the stress received at the time of cutting until it is cooled, and the cut object 18 shown in FIG.
The foamable polystyrene chip is deformed into a saddle shape as shown in FIG. The expandable polystyrene chip deformed in the saddle shape is pre-expanded with steam to obtain a bulk density of 0.01
6 g / cm ³ of prefoamed chips, ie extruded chips 1a made of polystyrene foam shown in FIG. 3, are obtained.

The extruded chips pre-foamed as described above were stored at room temperature for 1 day, and then the chips were filled with 0.2
The cavity of a molding die consisting of a female die and a male die having a large number of 5 mm diameter steam holes is filled into the cavity, and pressurized steam of 160 ° C is introduced into the cavity after the die is clamped. Is melted to fuse the chips together.
Next, the molding die is cooled to 35 ° C., and then the mold is opened to take out a block-shaped foam product having a length of 250 mm, a width of 400 mm, and a thickness of 80 mm, and foaming in the mold as shown in FIGS. 1 and 2. A molded body 1 was manufactured.

As the extruded chips, in addition to those obtained by prefoaming with steam, Japanese Patent Publication No.
It is also possible to use a product obtained by cooling a foam extruded through a profile die and then cutting it, as disclosed in JP-30102.

The physical properties of the block-shaped foam product produced are that the bulk density is 0.0093 g / cm ³ and the bending strength is 0.35 kg / cm ² , and it can withstand its intended use (for example, a cushioning material). Was confirmed. The porosity V is 1 in the longitudinal direction of the manufactured block-shaped foam product.
Measure the height hmm at which the water surface rises when submerged below the water surface of a water tank of 000 mm and 1000 mm in width, V (%) =
(250 × 400 × 80-1000 × 1000 × h) ÷
It was calculated by (250 × 400 × 80) × 100.

[0015]

The present invention is as described above, and unlike a cushioning material having no voids formed by using pre-expanded spherical polystyrene beads, the longest portion has a length of 2 cm or more, Since it is an in-mold foam molded product made of many polystyrene foam extruded chips having the same spherical shape, the apparent expansion ratio is very large due to the presence of voids,
In other words, the bulk density is small.

Therefore, not only is it advantageous in saving the material required for molding, but the newly manufactured extrusion molded chip has a smooth surface, and the fusion of the chips is strong. As a result, the strength of the molded product as a whole is high, and in combination with the existence of voids, it can be effectively used as a drainage material.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a partially enlarged sectional view of FIG.

FIG. 3 is a perspective view of an extrusion molded tip.

FIG. 4 is a perspective view showing deformation of an extrusion-molded chip.

FIG. 5 is a perspective view showing another modification of the extrusion molded tip.

FIG. 6 is a perspective view showing still another modification of the extrusion molded tip.

FIG. 7 is a schematic side view for explaining the manufacturing process of the extrusion molded chip.

[Explanation of symbols]

 1 is an in-mold foam molded product 1a, 1b, 1c, 1d is an extrusion molded chip 2 is a void

Claims (1)

[Scope of utility model registration request] 1. An in-mold foam molded article made of polystyrene foam and having a non-spherical shape and a plurality of extruded chips each having the longest length of 2 cm or more, and the surfaces of these extruded chips are adjacent to each other. Due to the fusion bonding, the voids exist between the chips, and the void ratio is 5 to 4 of the total volume.
A polystyrene foamed molded product characterized by being 0%.