JP2001287233A - Expandable profile resin particle and cellular molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide expandable profile resin particles and a cellular molding which can obtain high permeability, can be produced easily, are stable in shape. SOLUTION: In the expandable profile resin particle 10 having six stripe parts A-F which are arranged radially at every 60 around the axis, the length of the radial stripe parts A, C, E arranged alternately is 1.5-3 times as long as the length of the residual radial stripe parts B, D, F so that high permeability can be obtained, the production is easy, and the shape is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to foamable irregularly shaped resin particles and foamed molded products obtained from the particles, and more particularly to breathability and water permeability used for civil engineering and construction materials, horticultural materials, cushioning materials for packing and the like. And a foamable irregularly shaped resin particle used for the foamed molded article.

[0002]

2. Description of the Related Art Conventionally, spherical expandable resin particles are pre-expanded, the obtained pre-expanded particles are coated with an adhesive, filled in a mold, and the pre-expanded particles are bonded to each other with an adhesive. By heating to a certain degree and shaping, a foam molded article having voids has been obtained. The porosity of the molded article produced by such a method is determined by the amount of the adhesive used. However, when the amount of the adhesive is reduced to increase the porosity, the strength of the expanded molded article tends to be insufficient due to insufficient adhesion between the pre-expanded particles. However, there has been a problem that the ratio of the foamed molded article decreases and the weight of the foamed molded article increases.

[0003] Further, in a usual method without using an adhesive, a spherical foamable resin particle is pre-foamed, the obtained pre-foamed particle is filled in a mold, and a foam molded article is obtained by heat molding. There is a method of obtaining a foamed molded article having a high porosity as a state of partial fusion failure without bringing the pre-expanded particles into a completely fused state. However, in this case, there was a problem that a foam molded article having sufficient strength could not be obtained due to insufficient adhesion between particles.

[0004] Further, as described in JP-A-60-104318, an extruder having a die is used as the irregularly-shaped foamable resin particles. There is known a method of extruding into a columnar shape or the like and cutting the same into a predetermined shape to produce expandable irregular resin particles. The foamable irregularly shaped resin particles thus obtained are prefoamed, and are usually used as a cushioning material for packing or the like as a foamed body having a curved or saddle shape.

[0005] In addition, the foamable irregularly shaped resin particles are pre-foamed, the pre-foamed particles are filled in a molding die, and then the pre-foamed particles are fused to each other by steam heating. Thus, a foam molded article having a high porosity can be produced. In such a molding, when spherical expandable resin particles are used, the pre-expanded spherical particles are melt-fused in a state where they are in close contact with each other without a gap, and a foam molded article having a low porosity is formed. . But not spherical
When an irregularly shaped foamable resin particle is used, the particles are fused to each other due to the shape of the particle, but because they do not adhere to each other without a gap, a foam molded article having a high porosity and water permeability can be obtained. It becomes possible. As described above, foamed molded articles having a high porosity obtained by molding foamable deformed resin particles are used as, for example, drainage culverts for civil engineering work, heat-insulating dual-purpose panels having drainage properties, homes, and the like. It is used for lightweight blocks and the like. However, the shape of the foamable irregularly shaped resin particles conventionally used is such that the shape of the pre-expanded particles is large and the filling hole to be filled in the mold is easily clogged, so that the productivity of the foamed molded article tends to be low. There is a problem that when the filling property is improved by adopting a small-diameter shape, the productivity is improved, but the porosity is reduced.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made on the background of such prior art, and has a high porosity, so that a foam molded article having high water permeability can be obtained. The foamed molded product has sufficient strength and can be used for applications requiring high strength, such as civil engineering applications. It is an object of the present invention to provide expandable irregularly shaped resin particles that do not reduce the efficiency and a molded article thereof.

[0007]

That is, the expandable deformed resin particles of the present invention are expandable deformed resin particles having six striated portions, and each striated portion has an angle of 60 ° with respect to the axis. At two angles that extend radially at an angle and that are opposed to the axis, the length of one of the lines is 1.5 to 3 times the length of the other line. It is characterized by being. When the six striated portions are radially spread around the axis at an equal interval of 60 °, when the expandable irregularly shaped resin particles of the present invention are used as pre-expanded particles, It is possible to smoothly perform the filling operation from the filling hole into the mold. This is because the overall shape is close to a spherical shape, so that it is difficult for the particles to be entangled with each other to form an aggregate or to form an arch near the filling hole and to be closed. Further, in this shape, since the striated portions are radially spread around the axis, the adjacent pre-expanded particles are fused with each other in a state where the space between the striated portions of the pre-expanded particles is secured. To make things possible. In addition, since the length of each filament portion from the axis is not the same and one of the filament portions facing the axis is 1.5 to 3 times the length of the other filament portion, the molding die When filling into
It is possible to produce a molded article having a good porosity without clogging the filling hole. If the length is less than 1.5 times, the whole will have a uniform shape, will have a shape close to a sphere at the time of preliminary foaming, and a molded article having sufficient water permeability will not be able to be formed. On the other hand, when the length is more than three times, the productivity from the extruder may decrease, and further, the particles may be easily entangled with each other, and the filling property into the mold may be reduced. Is undesirably high.

[0008] The particle diameter of the foamable irregularly shaped resin is as follows:
Those having a range of 0 to 10 mm are preferred. The particle diameter of the expandable irregularly shaped resin particles of the present invention is the total length of two linear portions opposed to the axis. If the diameter is less than 1.0 mm, it will be difficult to obtain a sufficient porosity, and it will be impossible to obtain desired water permeability. On the other hand, if it exceeds 10 mm, the pre-expanded particles themselves will be large, and it may not be possible to mold a foam molded article having a porosity.

[0009] In the foamable irregularly shaped resin particles of the present invention, it is preferable that adjacent linear portions have different lengths from the axis. If the lengths of the adjacent linear portions are approximately the same from the axis line, in the pre-foaming stage, depending on the expansion ratio, the adjacent linear portions are foamed in such a shape as to be integrated with each other, and the obtained molding The porosity may not be sufficiently ensured in the body.

Further, the expandable irregularly shaped resin particles of the present invention are
The length in the axial direction is preferably 2 cm or less. If the length in the axial direction exceeds 2 cm, the filling property is poor at the time of filling in a molding die, and the productivity is undesirably reduced. Further, it is preferable that the length is equal to or longer than the particle diameter of the expandable irregularly shaped resin. If the particle diameter is shorter than the above-mentioned particle diameter, the particles may be easily bent, and a desired porosity may not be obtained. Further, the width of the striated portion is preferably 0.5 to 1.0 mm. If the width is less than 0.5 mm, it is difficult to maintain the shape when discharging from the die, and the possibility that a desired irregular shape cannot be formed increases. On the other hand, 1.0
mm, when the pre-foaming, the gap between the adjacent striated portions is not secured, the striated portion becomes like a fused shape, and when formed into a molded body, the void portion is not secured In some cases, desired water permeability is not ensured.

In the present invention, the main raw material of the expandable irregular resin particles may be any resin as long as it is a resin used for ordinary expandable resin particles. For example, styrene-based resins, olefin-based resins such as polyethylene and polypropylene, and the like can be given. The styrene-based resin as used herein means a styrene homopolymer and at least 5
It means a copolymer of 0% by weight, preferably at least 75% by weight, of styrene and another copolymerizable monomer.
Other copolymerizable monomers include ethylenically unsaturated monomers, such as α-methylstyrene, nuclear halogenated styrene, nuclear alkylated styrene having 1 to 4 carbon atoms in the alkyl group, acrylonitrile Methacrylonitrile, an ester of an alcohol having 10 to 10 carbon atoms with acrylic acid, methacrylic acid or fumaric acid, N-vinyl compounds such as butadiene, N-vinylcarbazole, N-vinylpyridine, or butanediol Examples thereof include divinyl compounds such as acrylate and divinylbenzene. Further, as the resin serving as the raw material of the present invention, a recycled material can be preferably used depending on the intended use.

Further, as the foaming agent used in the present invention, a foaming agent used for ordinary foamable resin particles or foamable resin pellets (hereinafter collectively referred to as “foamable resin particles”) is used. You. Preferably, an aliphatic or alicyclic hydrocarbon which does not dissolve the base resin but can be uniformly dispersed in the particles, for example, propane, n
-Butane or i-butane, n-pentane, i-pentane, hexane, cyclohexane and the like can be used alone or in combination of two or more. The timing of adding the foaming agent to the expandable irregularly shaped resin particles is not particularly limited.For example, a monomer resin is polymerized to form resin particles, and the foaming agent is added to the resin particles. Then, as the expandable resin particles, the expandable resin particles are put into an extruder, and may be the expandable deformed resin particles of the present invention, or the resin may be kneaded in the extruder, and then a blowing agent is added. Then, it may be extruded by an extruder to form expandable irregularly shaped resin particles. Further, after forming the deformed resin particles with an extruder, a foaming agent may be added to form the deformable resin particles.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an expandable irregularly shaped resin particle and an expanded molded article according to one embodiment of the present invention will be described. FIG.
1 is a perspective view of an expandable irregular resin particle according to one embodiment of the present invention. FIG. 2 is a perspective view of a foam molded article according to one embodiment of the present invention. 3 (a) to 3 (d) are front views of expandable deformed resin particles according to the conventional means.

In FIG. 1, reference numeral 10 denotes an expandable irregularly shaped resin particle. The expandable irregularly shaped resin particle 10 has six linear portions A to F radially arranged at intervals of 60 ° about an axis. In addition, the radial length r1 of the other linear portions A, C, and E is 1.5 times the radial length r2 of the remaining linear portions B, D, and F. . The width t of the linear portions A to F is 1.0 mm, and the length L in the axial direction of the expandable resin particles 10 is 5 mm.

The foamable irregularly shaped resin particles 10 are extruded by an extruder (not shown) using a die. The shape of the extrusion hole of the die is substantially the same as the cross-sectional shape in a direction perpendicular to the axis of the expandable resin particles 10. A specific extrusion molding method for the expandable irregularly shaped resin particles 10 is as follows. A styrene-based resin to which a predetermined amount of a foaming agent is added is put into an extrusion molding machine, and after heating, a string is intermediately manufactured through an extrusion hole of a die. . The cross-sectional shape of the string is the same as that of the expandable resin particles 10. Then, the string immediately after production is cooled by passing through a cooling water tank when resin foaming by the foaming agent is about to start, and then continuously cut to a length of 5 mm by a pelletizer. Thus, the expandable irregularly shaped resin particles 10 are manufactured.

The foamable irregularly shaped resin particles 10 are molded into a foamed resin block for embankment, which is a kind of civil engineering material, using a molding die. That is, first, expandable irregularly shaped resin particles 1
0 is heated to, for example, 95 to 110 ° C. and foamed 20 to 30 times, and then the foamable irregularly shaped resin particles 10 after the prefoaming are filled in a molding die and steam molded. At this time, the pre-expanded expandable deformed resin particles 10 hardly lose their shapes, but merely fuse adjacent ones. Thereby, the foaming resin block 20 for embankment as shown in FIG. 2 is manufactured. Since the foamable deformed resin particles 10 after the prefoaming have almost the same shape as the foamable deformed resin particles 10 before the prefoaming, the manufactured foamed resin block 20 for embankment has good water permeability. In addition, since the length L in the axial direction of the expandable irregularly shaped resin particles 10 is as short as 5 mm, a special take-off device is not required at the time of extrusion molding of the resin particles 10, and the foamed resin for embankment using a molding die is not required. The manufacture of the block 20 is also facilitated.

Here, the conventional expandable resin particles 100 to 103 shown in FIGS. 3A to 3D will be described. FIG.
As shown in (a), the radial length r3 of the linear portion 10a of the expandable irregularly shaped resin particles 100 having a cross shape is equal to 0.
A foamed resin block for embankment was obtained by the same process as described above, having a size of 8 mm or 1.0 mm, but none of them had water permeability. Further, as shown in FIG. 3B, the length r4 of every other linear portion 101a is changed to the remaining linear portion 100a.
Resin particles having twice the length r3 of a were obtained. A foamed resin block for embankment was obtained by the same process, but had a strong expansion performance, filled up the gaps, and had no water permeability. FIG.
(A) and FIG. 3 (b), during extrusion molding, it was able to be cut and taken by a usual cord-like material take-off device.

Therefore, since the water permeability cannot be exhibited unless the shape is different, foamable deformed resin particles 102 and 103 having the shapes shown in FIGS. 3 (c) and 3 (d) were tried. As shown in FIG. 3 (c), expandable irregular resin particles 1 having a substantially L-shaped cross section
02 have dimensions c1 = 4 mm and c2 = 1.0 m
m, c3 = 1.5 mm, c4 = 2 mm, c5 = 1 mm,
c6 = 2 mm. The dimensions of each part of the expandable resin particles 103 having a U-shaped cross section shown in FIG. 3D are d1 = 1.0 mm, d2 = 3.0 mm, and d3 = 1.
0 mm, d4 = 1.0 mm, and d5 = 3.0 mm.

These expandable irregularly shaped resin particles 102, 10
In the production of No. 3, a foaming agent was press-fitted into the raw material resin during extrusion molding by an extrusion molding machine, and was discharged from a die to the outside. After that, since it was immediately cooled with water, these special shapes were maintained, but flattened between the rubber rolls of the take-up device. Therefore, the cord was manually pulled off and cut to a predetermined size. After curing,
Pre-foamed at 100 ° C, length 100mm x width 300mm x
A foamed resin block for embankment having a height of 300 mm was obtained. However, the foaming resin block for embankment obtained above expands and foams at the molding stage, and the foaming pressure causes the shape of the foamable irregularly shaped resin particles 102 and 103 after the prefoaming to collapse, and the water permeability is only slight. Met. Here, if the length of each part of d1, d3, d4 is increased,
It was further found that the water permeability decreased.

As a result of various studies, it was found that good water permeability can be obtained by forming the resin particles 10 into a shape like the expandable resin particles 10 as shown in FIG. However, the striated part A ~
It was also found that when the width t of F was 1.0 mm or more, the foamability increased, the tendency to fill the gaps between the linear portions A to F became strong, and the water permeability tended to deteriorate.

Here, an expanded molded article (foamed resin block for embankment) using the expandable deformable resin particles e of the present invention as a raw material and the same shape formed from the conventional expandable deformable resin particles a to d are used. The following are the results of a string-like material take-off test, a mold filling property of expandable irregularly shaped resin particles, and a water permeability test of the foamed molded article, using the foamed molded article. In Table 1,
The line width is the width of a die of an extruder. The length is the length in the axial direction of the expandable irregular resin particles. The filling property of the expanded particles is whether or not it can be automatically filled into a molding die. For measuring water permeability, a foam molded product was measured for a thickness of 50 mm.
This was placed in a cylindrical body having a diameter of 100 mm, water was further added, and the amount of water passing through the foamed molded article within a predetermined time was measured. In addition, (long / short) 1.5 in Table 1 indicates that the length of the long linear portion in the radial direction is 1.5 times the length of the short linear portion in the radial direction. (Long / short) 1.0,
In the case of (long / short) 4, only the magnification is different.
The evaluation is in the order of ○, △, ▲, × from good to bad.

[0022]

[Table 1]

As described above, even with the expandable irregular resin particles e of the present invention having the same cross-sectional shape, the water permeability and other performances were affected depending on the conditions.

[0024]

According to the present invention, 6 axes around the axis are provided.
The foamed irregularly shaped resin particles having six linear portions radiated at every 0 °, and the radial length of every other linear portion is the radial length of the remaining linear portion. Since the thickness is 1.5 to 3 times, high water permeability is obtained, and the production is easy and the shape is stable. In addition, for example, at the time of extrusion molding, a foamed molded article having good water permeability (such as a water-permeable block) can be easily produced with existing equipment as compared with a conventional method. That is, in the case of a water-permeable block manufactured with an adhesive or the like, it has been time-consuming to cut into a required shape because it has to be mechanically cut. On the other hand, in the present invention, since it can be manufactured in the form of a block, water permeability can be obtained even if it is cut from any part as required, and versatility is improved. For example, pots that need drainage, such as plants that are easily rotted, can be manufactured by a normal molding method. In addition, even when manufacturing in large quantities,
Cost reduction can be achieved, and water permeability can be easily increased by adjusting various conditions such as the length in the axial direction of the expandable deformed resin particles. Moreover, the compressive strength of the foamed molded article can be relatively easily controlled by adjusting the amount of the foaming agent added to the raw materials.

[Brief description of the drawings]

FIG. 1 is a perspective view of an expandable irregularly shaped resin particle according to one embodiment of the present invention.

FIG. 2 is a perspective view of a foam molded article according to one embodiment of the present invention.

3 (a) to 3 (d) are front views of foamable irregularly shaped resin particles according to a conventional means.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 foamable irregularly shaped resin particles 20 foamed molded article A to F

Claims (4)

[Claims] 1. A foamable irregularly shaped resin particle having six striated portions, wherein each striated portion is radially spread at an angle of 60 ° about an axis, and is opposed to the axis. In the striated portion of the book, the length of one striated portion is 1.5 to 3 times the length of the other striated portion. 2. The expandable irregularly shaped resin particles according to claim 1, wherein adjacent linear portions have different lengths. 3. The expandable irregularly shaped resin particles according to claim 1, wherein the length in the axial direction is 2 cm or less, and the width of each linear portion is 0.5 to 1.0 mm. 4. Pre-expanding the expandable deformable resin particles according to claim 1 to prepare pre-expanded particles,
A foam molded article characterized by filling a molding die with the pre-expanded particles and fusing the pre-expanded particles to each other by heat molding.