JPH07119308B2 - Method for producing polystyrene foam - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polystyrene foam suitable for an in-situ foaming method or a method of using a foam for ground improvement.

[0002]

2. Description of the Related Art Polystyrene foams are small in deformation against external stress, and are excellent in shape retention and dimensional stability. They are used for packaging and packing of home electric appliances and precision equipment, cooler boxes, heat insulating building materials. It has been widely used for.

In recent years, blocks made of polystyrene foam are vertically and horizontally stacked on soft ground, sloping ground or landslide areas to construct a bank of embankment, on which bridges, paved roads, airfields, railways, etc. are provided. Civil engineering method called EPS method has also become popular.

As a conventional method for producing such a useful polystyrene foam, polystyrene beads containing a foaming agent are filled in a mold (mold, template, trapezoid, sink, etc.), and steam is used. It is usually carried out by a bead molding method in which heat energy is supplied for molding, a polystyrene raw material is melted by heating using an extruder, a foaming agent is mixed, and then extruded in a sheet form.

All of these conventional foaming methods are based on the so-called external heating method in which foaming is performed by heating from the outside.

However, since such an external heating method requires a large-scale heating facility, it is manufactured in a factory equipped with the heating facility, and after being made into a foam form, it is later used by a user or a construction site at a remote place. It is usually transported to and used. For this reason, there are drawbacks such that transportation costs and storage costs are increased due to the bulkiness of the foam, resulting in an extremely high cost.

To solve this problem, Japanese Patent Laid-Open No. 63-134
Japanese Patent No. 708 proposes a quicklime-based ground improvement material and a ground improvement method which are obtained by mixing quicklime with polystyrene as a raw material for molding. This method is to use polystyrene as a ground improvement material by foaming polystyrene by utilizing the exothermic reaction of quick lime and water, but due to low exothermic temperature, time required to generate heat, short exothermic time, etc. , The expansion ratio of the foam is extremely low, a large amount of resin is required, and the construction cost is high, the foaming speed is slow and the construction efficiency is poor, and the bonding between the foam particles is weak, and it is difficult to obtain a solid three-dimensional molded article. There was a problem.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and it is desired to use a foam without using an external heating device, a foam construction site. It is an object of the present invention to provide a method for producing a polystyrene-based foam which is capable of being foamed and foam-molded by, and has a high expansion ratio and which allows rapid expansion.

[0009]

[Means for Solving the Problems] The present inventors finally arrived at the present invention as a result of intensive studies for many years. The outline is as follows.

That is, the method for producing a polystyrene-based foam is characterized in that the heat of reaction produced mainly by mixing the following (1) to (3) is used for foaming.

(1) Expandable polystyrene resin (2) At least one or more chlorides of alkali metals and alkaline earth metals (3) Water component Alternatively, mainly, the following (1) to (4) are mixed. This is a method for producing a polystyrene-based foam, which is characterized in that foaming is performed by utilizing the reaction heat generated.

(1) Expandable polystyrene resin (2) At least one or more chlorides of alkali metals and alkaline earth metals (3) At least one or more oxides of alkali metals and alkaline earth metals ( 4) Water component, or as a method to which the present invention described above is applied,
A method for producing a polystyrene-based foam, which comprises molding the foam according to the method of the present invention into a foam of any shape in a mold of any shape, or a flexible bag-shaped container Among them, the method for producing a polystyrene-based foam is characterized in that a bag-filled foam is molded by causing foaming according to the method of the present invention.

Further, in the above-mentioned method of the present invention, preferably, the chloride of alkali metal and alkaline earth metal is magnesium chloride or calcium chloride, or the alkali metal and The oxides of alkaline earth metals are calcium oxide,
The method is characterized by using magnesium oxide or sodium oxide.

Further, a novel method for producing a polystyrene foamed molded article is obtained by carrying out the above-mentioned method for producing a foamed article of the present invention in a mold of an arbitrary shape or in a space in a flexible container for foaming and molding. Is provided.

[0015]

The method for producing the polystyrene foam of the present invention will be described in detail below.

One of the features of the present invention is that at least a chloride of an alkali metal and an alkaline earth metal is used as a heat generating agent component, heat is generated by a reaction with water, and the heat source is used to form a foam. It is basically suitable for foaming without using a heating device and for producing a foamed product at a construction site without a heating device.

That is, according to the present invention, by using the chloride as the exothermic agent component, a method for foaming polystyrene utilizing the heat of reaction between quick lime and water according to the prior art (Japanese Patent Application Laid-Open No. Sho 6-62).
In comparison with Japanese Unexamined Patent Publication (Kokai) No. 3-134708), heat generation is remarkably quick, and excellent heat generation performance that heat is generated at a high temperature is utilized. Due to the heat generation performance, it is possible to carry out extremely high expansion and rapid foaming which have not been obtained so far, and it is possible to produce a foam having extremely strong bonding between foam particles. Further, by performing such foaming in the mold, it is possible to obtain a three-dimensional molded article of any shape. In addition, a bagged foam can be molded by foaming in a flexible bag-shaped container.

Examples of the polystyrene resin component of the present invention include polystyrene, styrene-ethylene copolymer,
A thermoplastic resin composed of one or more of acrylonitrile / styrene copolymer and ABS resin, which contains a low boiling point blowing agent such as propane, butane, pentane, hexaneheptane, cyclohexane and a mixture thereof. Used.

As chlorides of alkali metals and alkaline earth metals, calcium chloride and magnesium chloride are typical and preferable, and one or more of them are applied. The amount of the chloride added is not particularly limited, but is generally in the range of 1 to 100 parts with respect to 100 parts by weight of the resin in order to perform sufficient foaming. In practice, the amount added may vary greatly depending on the chloride species.

Further, in the present invention, by using such a chloride and an oxide of an alkali metal or an alkaline earth metal in combination, a high temperature state can be maintained for a long time, and preferable foaming can be carried out. Typical examples of such oxides are calcium oxide, magnesium oxide, and sodium oxide, and one or more of such oxides are applied. The mixing ratio of both and the mixing ratio of both components are not particularly limited and can be arbitrarily determined.

Further, in order to rapidly generate heat of the composition and increase the heat generation amount per unit of the exothermic agent component, it is preferable that the chloride or oxide has a large surface area and is uniformly dispersed between the resin particles. For that purpose, it is desirable to atomize chlorides and oxides. Any known method can be used for forming fine particles, and for example, a dry mill can be preferably used. The average particle size required to obtain good dispersion is approximately 0.1 μm or more, 1
The range is 000 μm or less.

The water component that causes the chloride and oxide to generate heat means that it contains at least water, and may be water alone, or an aqueous solution, dispersion, emulsion, etc. containing a surfactant, a resin, etc. Alternatively, it is not limited as long as it is a paste-like substance, a gel-like substance, a substance containing water in a solid such as a porous material, and the like, as long as water can contact the exothermic agent component and generate heat.

The mixing order is not particularly limited, and the blends may be mixed at the same time, or may be mixed individually in any order. A preferred method is to uniformly mix the foaming resin with the exothermic agent component and finally add water.

By performing foaming under pressure in a mold of an arbitrary shape, the bond between the foam particles is strengthened,
It is possible to obtain a solid three-dimensional molded product having an arbitrary shape. For example, it is possible to mold on-site a cushioning material for a home electric appliance or a fish box that is usually manufactured in a factory.

In addition, a flexible container (flexible,
It is also possible to form a foam that is wrapped in a flexible container (for example, a cloth bag, a film bag, or the like) by performing foaming in a container having various shapes. This foam formation method can be created by appropriately changing the density, size, shape, etc. according to the situation of the civil engineering site, etc.This foam is used for soft ground, steep slopes or landslide areas. It can be preferably used as a material for civil engineering work such as.

The method for producing a polystyrene-based foamed molded article by carrying out the above-mentioned method for producing a foamed article of the present invention in a mold of an arbitrary shape or in a space in a flexible container to perform foaming / molding is an emergency. It is also suitable for construction and construction in emergency situations.

Other heat-generating materials such as calcium hydroxide, magnesium hydroxide, barium hydroxide, flame retardants, neutralizing agents, fillers, plasticizers, pigments, dyes, etc. are added depending on the purpose of use and application. It does not matter what you do.

Further, as described above, external heating is not necessarily required to carry out the present invention, but various types of heating such as electric heaters, microwave heating, hot air heating, etc. can be performed depending on the specifications, applications, purposes, etc. There is no problem in using the heating method together.

[0029]

According to the present invention, in-situ foaming is possible not only in a place where there is no heating device, but the calorific value is high, and the heat generation is rapid and lasts for a long time. It enables foaming, rapid foaming, and strong bonding between foam particles, and a three-dimensional molded article of any shape can be obtained.

[0030]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the scope of the validity and rights of the present invention is not limited by or limited thereto.

Example 1 Commercially available polystyrene expandable beads were used as the expandable resin component, and magnesium chloride was used as the exothermic agent component, and 30 parts by weight of magnesium chloride was added to 100 parts by weight of the expandable beads and mixed. Internal dimensions are 500mm (vertical) x 250mm (horizontal) after both components are thoroughly mixed
It was put into a metal mold with a lid of × 200 mm (height). Water was sprayed and supplied while stirring both components using a stirrer. Immediately after spraying water, heat was generated and foaming started. The lid of the metal mold was closed to allow sufficient foaming. Foaming was complete after about 1 minute. A block-like foam having the above-mentioned mold size was obtained. The foaming ratio of the block-shaped foam was about 25 times.

A compression test was conducted by applying the block-shaped foam to a road model of EPS method. as a result,
It was found to have the same degree of compression resistance as a foam block molded in a conventional factory.

Example 2 Commercially available polystyrene expandable beads were used as the expandable resin component, and magnesium chloride and calcium oxide were used as the exothermic agent components. 10 parts by weight of magnesium chloride and calcium oxide were added to 100 parts by weight of the expandable beads. 10 parts by weight were added and mixed. After both components are mixed well, the internal dimension is 500 mm (vertical) x 250 mm (horizontal) x 100
It was placed in a metal mold with a lid of 0 mm (height). The expandable beads / magnesium chloride / calcium oxide blend was agitated using a stirrer while being sprayed with water and fed. Immediately after spraying water, heat was generated and foaming started. The lid of the metal mold was closed to allow sufficient foaming. Foaming was complete after about 2 minutes. A block-like foam of approximately the above dimensions was obtained. The foaming ratio of the block-shaped foam was about 25 times.

The obtained block-shaped foam had a compression resistance almost equivalent to that of Example 1, and was applicable to the EPS method.

Example 3 Commercially available polystyrene expandable beads were used as the expandable resin component, and calcium oxide, calcium hydroxide, magnesium chloride, and calcium chloride were used as the heat-generating component, and calcium oxide was added to 100 parts by weight of the expandable beads. Parts by weight, 5 parts by weight of calcium hydroxide, 10 parts by weight of magnesium chloride and 5 parts by weight of calcium chloride were added and mixed. These formulations were mixed well and then fed into a metal mold having a fish box shape. After closing the metal mold, water was added by injection through a large number of pores arranged in the metal mold. Exotherm started immediately after the addition of water and foaming started a little later. After about 2 minutes, foaming was completed and a fish box of the desired shape was obtained. The expansion ratio of the foam was about 30 times. Although the foam had some uneven expansion ratio, it had no problem in practical use.

Example 4 Commercially available polystyrene expandable beads were used as the expandable resin component, calcium oxide, magnesium chloride as the exothermic component, and polyvinyl alcohol as the moisture component.
% Aqueous solution, 20 parts by weight of calcium oxide, 10 parts by weight of magnesium chloride, and 20 parts by weight of an aqueous solution of polyvinyl alcohol were added to 100 parts by weight of the expandable beads and mixed with a stirrer. After such a formulation was thoroughly mixed, the mixture was fed into a cloth bag made of polypropylene slit yarn fabric. Then, the opening of the cloth bag was tied with a string and foamed to the full volume to obtain a foamed product with a cloth bag. After about 3 minutes, foaming was almost complete. The expansion ratio of the foam with a cloth bag was about 25 times.

When the obtained foam with a cloth bag was used as an embankment (sandbag) on soft ground, it was possible to carry out civil engineering work without any practical problems.

Claims (8)

[Claims] 1. A method for producing a polystyrene-based foam, which comprises foaming mainly by utilizing reaction heat generated by mixing the following (1) to (3). (1) Expandable polystyrene resin (2) At least one or more chlorides of alkali metals and alkaline earth metals (3) Water component 2. A method for producing a polystyrene foam, which comprises foaming mainly by utilizing reaction heat generated by mixing the following (1) to (4). (1) Expandable polystyrene resin (2) At least one or more chlorides of alkali metals and alkaline earth metals (3) At least one or more oxides of alkali metals and alkaline earth metals (4) Water component 3. The method for producing a polystyrene-based foam according to claim 1, wherein the foamed product is molded into a foam having an arbitrary shape by foaming in a mold having an arbitrary shape. 4. The method for producing a polystyrene foam according to claim 1 or 2, wherein the foamed bag-filled foam is molded in a flexible bag-shaped container. 5. The method for producing a polystyrene foam according to claim 1, wherein the chloride of the alkali metal and the alkaline earth metal is magnesium chloride or calcium chloride. 6. The oxides of alkali metals and alkaline earth metals are calcium oxide, claim 2, wherein the magnesium oxide or sodium oxide, 3
Alternatively, the method for producing a polystyrene-based foam according to item 4. 7. A polystyrene foam is foamed / molded mainly by using reaction heat generated by mixing the following (1) to (3) in a mold of arbitrary shape or in a space of a flexible container. A method for producing a polystyrene-based foamed molded article, comprising: (1) Expandable polystyrene resin (2) At least one or more chlorides of alkali metals and alkaline earth metals (3) Water component 8. A polystyrene foam is foamed / molded by utilizing reaction heat generated mainly by mixing the following (1) to (4) in a mold having an arbitrary shape or in a space in a flexible container. A method for producing a polystyrene-based foamed molded article, comprising: (1) Expandable polystyrene resin (2) At least one or more chlorides of alkali metals and alkaline earth metals (3) At least one or more oxides of alkali metals and alkaline earth metals (4) Water component