JPH0780873A - Styrene-modified polyolefin-based resin foam-molded body - Google Patents

Abstract

PURPOSE:To manufacture foam-molded body, which has enough large compression strength for withstanding against the use as underdrainage material, sound absorbing material or the like and can stably get the desired voids without using adhesive. CONSTITUTION:The styrene-modified polyolefin-based resin foam-molded body concerned is obtained by thermally expanding styrene-modified polyolefin-based resin foaming particles 2 in a mold so as to fuse the particles 2 together in order to have the void of 10-40%.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention is excellent in water permeability, heat insulation and sound absorption, and has high compressive strength.
The present invention relates to a styrene-modified polyolefin resin foamed molded product that can be used as a drainage material for a culvert in a ground, an outer wall of a basement, a roof garden, or the like, or as a sound absorbing material.

[0002]

2. Description of the Related Art Recently, in order to improve the drainage performance of golf courses, grounds, etc., a drainage material composed of a resin foam molding having a closed cell structure has been buried in the ground. For example, polystyrene foam particles having a closed cell structure, such as those manufactured by Mitsubishi Petrochemical Bardish Co., Ltd. (trade name: styrodren), are bonded with an adhesive to form 10
Molded articles having ˜50% interparticle voids are used. Further, regarding the fact that a polyolefin resin foam molded article is used as a drainage material and a method for producing the foam molded article, JP-A-3-224727 and JP-A-4-77 are also disclosed.
It is disclosed in Japanese Patent No. 532 and is publicly known.

[0003]

Of the above-mentioned conventional techniques,
Drainage material made by adhering polystyrene foam particles with an adhesive has a weak adhesive force between particles and is fragile.
It has the drawback that it is easily damaged and easily soiled. Further, polystyrene foamed particles have a strong foaming power, so that it is difficult to stably obtain a molded product having a desired porosity, and when the porosity is increased, there is a drawback that the adhesive force between particles becomes weak.

On the other hand, since the polyolefin resin foam molded article has low hardness and compressive strength, it is compressed and deformed by the weight of the earth and sand covering it when it is buried after construction, and the ground surface of the buried part sinks. However, there is a problem in that the water permeability is significantly reduced. Although it is possible to form voids in a polyolefin resin foamed molded product, the allowable range of steam pressure and heating time at the time of molding is narrow, and further, at low density, it tends to shrink at the time of molding, resulting in compressive strength. Since it is also low, it is not suitable to use as a drainage material for underdrain.

The present invention has been made in view of the above conventional problems, and an object thereof is to have a compressive strength sufficient to withstand use as an underdrain drainage material, and to stably obtain a desired value. Another object of the present invention is to provide a foamed molded article which can obtain the porosity of 1 and can be manufactured without using an adhesive and does not stain the workplace, work clothes, etc. with the adhesive.

[0006]

The present invention has been made as a result of intensive studies for solving the above-mentioned conventional problems, and is made by using a small piece of styrene-modified polyolefin resin foam in a mold. Styrene reforming, which is a foamed molded article obtained by heat-foaming and fusing small pieces to each other, wherein the small pieces are fused so as to have a void of 10 to 40% between the small pieces. It is intended to provide a polyolefin resin foam molding.

The styrene-modified polyolefin resin foam molding of the present invention has a sufficiently high compressive strength, can stably obtain a desired porosity, and can be manufactured without using an adhesive. It is extremely suitable for use as an underdrain drainage material.

Styrene-modified polyolefin resin foam pieces are prepared by suspending a styrene monomer and a polyolefin such as polyethylene or polypropylene in an aqueous medium to polymerize the styrene monomer, and at that time, adding a volatile expanding agent. It is also impregnated to produce a foamable styrene-modified polyolefin-based resin piece, and then the foamable piece is heated. In addition, the polymerization ratio of the styrene-based monomer and the polyolefin resin piece is styrene-based monomer-1.
Polyolefin resin 10 to 400 for 100 parts by weight
The amount is preferably 30 parts by weight, particularly 30 to 110 parts by weight. The shape of the foam piece may be a spherical shape, a saddle shape, a string shape, or the like, but it is particularly effective when spherical particles are used as compared with the conventional method. In the case of a spherical shape, for example, those having a particle size of about 2 to 20 mm can be used.

The foam pieces thus obtained are filled in a mold at 80 to 100% and the steam pressure is set at 0.05 to
By heating at 0.5 kg / cm ² for ² to 30 seconds, a styrene-modified polyolefin resin foam molded article having a porosity of 10 to 40% can be obtained.

[0010]

EXAMPLES Next, various characteristics of the styrene-modified polyolefin resin foam molded article of the present invention will be described in comparison with conventional foam molded articles.

The porosity, fusion property (adhesion strength between particles), water permeability and compressive strength of each foamed molded article were measured or determined in the following manner. * Porosity 1000 × (longitudinal) for the block-shaped foam molded product manufactured
(Horizontal) The rising height hmm of the water surface when completely submerged in water stored in a water tank having an inner size of 1000 mm was measured, and calculated from (foam volume-1000 × 1000 × h) ÷ foam volume × 100 did. * The surface of the fusible molding was scratched with fingers three times repeatedly, and the degree of separation of the surface particles was judged according to the following criteria. ◯: Strong (individual particles do not separate unless strongly scratched) Δ: Slightly weak (individual particles separate when scratched with moderate strength) □: Weak (individual particles fall apart only by weak scratching) X: Very weak (individual particles are released when released from the mold) * Water permeability Measured according to JISA1218. * Compressive strength Measured according to JIS K7220.

(Example 1) 400 × 400 × 100 mm
Styrene-modified polyethylene expanded particles obtained by suspension polymerization using 50 parts by weight of polyethylene with respect to 100 parts by weight of styrene monomer in a mold having an inner size of (expansion ratio 50 times, particle size 5.8 mm). 100% filled with
After heat-molding at a pressure of 0.15 kg / cm ² for 15 seconds, it was cooled for 180 seconds and the molded product was taken out.

(Comparative Example 1) Polypropylene foam particles (foaming ratio 45
Double, and the particle size was 5.0 mm), and molding was performed under the same conditions as in Example 1, but a molded body could not be manufactured due to defective fusion bonding.

(Comparative Example 2) Polystyrene expanded particles (expansion ratio 50) were used in place of the styrene modified polyethylene expanded particles.
Double, and a particle size of 5.0 mm) was used, and molding was performed under the same conditions as in Example 1.

(Comparative Example 3) 53 parts by weight of an asphalt emulsion adhesive (resin solid content) and 35 parts by weight of an acrylic emulsion adhesive with respect to 100 parts by weight of expanded polystyrene particles (foaming ratio 58 times, particle size 5.8 mm). Parts (resin solid content) were mixed, put in a molding box, and dried from the bottom with hot air at 50 to 55 ° C. to completely remove water.

(Comparative Example 4) 100% polypropylene expanded particles (foaming ratio 45 times, particle size 5.0 mm) were filled in the mold used in Example 1 and steam was sufficiently melted to achieve sufficient fusion. After heat molding for 3 seconds at a pressure of 2 kg / cm ² , 1
After cooling for 80 seconds, the molded product was taken out. Due to the high steam pressure, the molded product showed a tendency to shrink.

COMPARATIVE EXAMPLE 5 Expanded polystyrene particles (expansion ratio 50 times, particle size 5.0 mm) were filled 100% in the mold used in Example 1 to obtain a high porosity. After heat-molding at a pressure of 0.1 kg / cm ² for 15 seconds, it was cooled for 180 seconds and the molded product was taken out.

Table 1 collectively shows various characteristics of the foamed molded articles produced in the above Examples and Comparative Examples.

[0019]

[Table 1]

[0020]

EFFECTS OF THE INVENTION The styrene-modified polyolefin resin foamed molded product of the present invention has a good drainage property because it has voids of 10 to 40%, and has sufficiently high compressive strength. It is very suitable for use. Further, it is possible to obtain a desired porosity in a stable manner, and it is possible to manufacture without using an adhesive.

[Brief description of drawings]

FIG. 1 is an external perspective view of a foam molded article.

[Explanation of symbols]

 1 foam molded body 2 foamed particles

Claims (1)

[Claims] 1. A foamed molded product obtained by heat-foaming small pieces of a styrene-modified polyolefin resin foam in a mold to fuse the small pieces together, and having voids of 10 to 40% between the small pieces. As described above, a styrene-modified polyolefin resin foamed molded product characterized in that the small pieces are fused together.