JP2002172621A - Method for transporting/preserving synthetic resin foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for transporting/preserving foam containing a volatile component safely at a low cost even when a preservation/curing period in which the discharge of the volatile component goes into remission is not taken when the foam containing the volatile component is transported and preserved. SOLUTION: When the synthetic resin foam is preserved in a warehouse and transported by a truck, a container, etc., an adsorbent substance for adsorbing the combustible, poisonous volatile component discharged from the foam and a support into which the adsorbent substance is inserted are made to exist in a housing space so that the foam can be transported and preserved safely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for safely transporting and storing a foam containing a volatile component such as a foaming agent in a synthetic resin foam.

[0002]

2. Description of the Related Art Conventionally, in the production of a synthetic resin foam, a physical foaming agent and a chemical foaming agent have been used as foaming agents. Particularly, in order to obtain a high-magnification foam, a physical foaming agent is often used. .

[0003] For example, in the production of an extruded styrene resin foam, a typical blowing agent is a chlorine atom-containing halogenated hydrocarbon (hereinafter abbreviated as CFC) which is obtained by partially hydrogenating chlorine atoms. Atom-containing halogenated hydrocarbon (hereinafter abbreviated as HCFC), fluorinated hydrocarbon (hereinafter, abbreviated as HCFC)
HFC), methyl chloride, ethyl chloride and the like are mainly used.

However, since methyl chloride, ethyl chloride and the like are substances that are required to protect the working environment in manufacturing factories and the like from the viewpoint of occupational health, it is preferable not to use these foaming agents. .

[0005] On the other hand, in recent years, the use of CFCs has already been regulated from the viewpoint of protection of the ozone layer in the stratosphere, and the use of HCFCs has also been regulated. Furthermore, the use of HFCs has also been reduced from the viewpoint of global warming. It is desired.

Under these recent circumstances, in the production of extruded styrenic resin foams, hydrocarbons and ethers are used as foaming agents in order to reduce the impact on health and reduce the burden on the environment. Has been proposed.

However, these foaming agents have high flammability as compared with fluorocarbons, and may burn even at a low concentration. Therefore, it is desirable to pay attention during production, storage and transportation. .

Regarding storage and transportation, the storage space is often a closed environment. In the case of a foam using a flammable foaming agent, the flammable gas gradually evaporates from the foam. It is conceivable that the concentration of the flammable foaming agent in the storage space gradually increases, and the possibility of combustion increases.

In the first place, although the foaming agent remaining in the foam varies depending on the type, the foaming agent is easily permeable from the foam within several days to several weeks and released from the foam within several months to several decades. It is separated from the low-permeability blowing agent that is released. Immediately after the production of the foam, the internal pressure of the foam changes due to the release of the readily permeable foaming agent from the foam and the inflow of air into the foam. Since the dimensional change of the foam is caused by the change of the internal pressure, the foam is stored in a warehouse for a certain period of time and shipped after the dimensional change of the foam is reduced.
Therefore, the easily permeable foam hardly remains when used by the consumer, and is in a state where it can be used safely.
However, during storage and transportation of the foam, the release of the readily permeable foaming agent may not be completed. Also,
When a large amount of foam is handled at the same time, the concentration of the volatile foaming agent tends to increase as a whole in a warehouse or during transportation.

In particular, trucks, containers, and the like used in transportation have a large difference in the degree of sealing depending on the type of the accommodation space. When a highly sealed accommodation space is used, the number of times of ventilation with the outside air decreases. Therefore, the concentration of each blowing agent in the system may eventually exceed the lower combustion limit concentration. In such a case, as a result, when an ignition source such as static electricity is present, there is no possibility that combustion or explosion may occur.

For this reason, in a foam using such a foaming agent, in a well-ventilated warehouse until the release of volatile components such as the foaming agent in the foam after production becomes lubricious, By ensuring a sufficient storage curing period, the release of volatile components during transportation has been suppressed, leading to increased costs such as increased warehouse construction costs and warehouse storage costs.

[0012]

DISCLOSURE OF THE INVENTION The present invention provides a method for transporting and storing a foam containing a volatile component without taking a storage curing period until the release of the volatile component from the foam becomes lubricious. It is an object of the present invention to provide a method for safely transporting and storing a foam containing volatile components at a lower cost.

An adsorbent is added to the base resin in order to adsorb volatile components such as ethylene gas, oxygen and carbon dioxide generated from these transported products in order to maintain the freshness of the transported products such as fruits and vegetables, flowers and fresh foods. It is known to use a kneaded foam or foam container with a freshness preserving agent (for example, JP-A-63-150353, JP-A-11-46677, etc.). Since the volatile component having flammability and the like released from the resin foam itself is adsorbed by the adsorbing substance for fire prevention, the essential point is different.

[0014]

That is, the present invention relates to (1) an adsorbing substance having an adsorbing capacity of at least 3.0 × 10 ^-5 mol / g for volatile components released from a synthetic resin foam. And a method for transporting and storing a synthetic resin foam. (2) The transport and storage method according to (1), wherein the adsorbed substance is an inorganic porous material or an organic gas adsorbent. (3) The adsorbed substance is zeolite, activated carbon, activated carbon fiber,
The transport and storage method according to the above (1) or (2), wherein the method is one or a combination of two or more selected from high molecular polymer adsorbents. (4) The transport and storage method according to any one of the above (1) to (3), wherein an adsorbed substance is wrapped with a nonwoven fabric, paper, plastic film, or the like. (5) The transport and storage method according to any one of (1) to (3), wherein the adsorbed substance is mixed with a polymer resin to form a sheet or a mat. (6) Any one of the above-mentioned items (1) to (3), wherein a pallet-shaped, saw-shaped, tubular, or sheet-shaped synthetic resin foam support on which an adsorbing substance is embedded or attached is used. Transport and storage methods as described. (7) The transport and storage method according to any one of (1) to (6), wherein the synthetic resin foam is a thermoplastic resin foam. (8) The transport and storage method according to any one of (1) to (6), wherein the synthetic resin foam is a polystyrene resin extruded foam. About.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a method for removing volatile components such as a foaming agent released from a synthetic resin foam when the synthetic resin foam is transported and transported by a warehouse, truck, container or the like. It is carried out by allowing an adsorbing substance having an adsorbing ability and an adsorbing substance to coexist in the accommodation space.

The synthetic resin foam is, for example, a thermoplastic resin foam or a thermosetting resin foam. Examples of the thermoplastic resin foam include foams of an aromatic vinyl resin such as a polystyrene resin and a polyolefin resin such as a polyethylene resin and a polypropylene resin.
Examples of the thermosetting resin foam include a foam such as a phenolic resin. Of these, a thermoplastic resin foam is particularly preferred.

More preferably, it is a polystyrene resin foam. In the polystyrene resin foam, hydrocarbon, methylene chloride, HCFC, HFC, dimethyl ether and the like are often used as a foaming agent. Since the foaming agent is held in the foam for a long time due to the low gas permeability of the foam, volatile components mainly composed of the foaming agent in the foam are easily released even during storage and transportation. The present invention is very effective because the possibility of combustion during transportation increases.

The adsorbent used in the present invention includes an inorganic porous material and an organic gas adsorbent. More specifically, the adsorbent is selected from zeolite, activated carbon, activated carbon fiber, activated alumina, and polymer adsorbent. And adsorbed substances that are one or more combinations of the above.

The volatile components absorbed by the adsorbent according to the present invention are mainly foaming agents such as hydrocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, alkyl chlorides and ethers. Of these volatile components, which are mainly foaming agents, particularly C ₃ -C ₅
(Propane, cyclopropane, n-butane, i-butane, cyclobutane, n-pentane, i-pentane, neopentane, cyclopentane), dimethyl ether, methyl chloride, and ethyl chloride.

In the case of C ₃ -C ₅ saturated hydrocarbons and dimethyl ether, the lower limit of combustion limit is very low (for example, 2.1 vol% for propane, 1.8 vol% for butane, 3.4 vol% for dimethyl ether), Since there is a high possibility of combustion even at a low concentration, the danger can be sufficiently reduced by using an adsorbent.

Methyl chloride and methylene chloride are substances that are required to protect the working environment in manufacturing plants and the like from the viewpoint of occupational health, and the use of adsorbed substances can reduce the effect on health. I can do it.

The adsorption amount of volatile components of these adsorbed substances is
3.0 × 10 / g^-Fivewith adsorption capacity of at least mol
Are desirable, and a more preferred range is 6.0 ×
10 ^-FiveIt has an adsorption capacity of at least mol. After this
If it is below, when the gas concentration in the accommodation space becomes high
Expect sufficient effect, because the amount of adsorption is very low
When using a large amount of adsorbed substances,
In addition, the operation cost is affected.

Examples of the adsorbing substance that satisfies the above conditions include zeolite, activated carbon, activated carbon fiber, high molecular polymer adsorbent, etc., and the gas adsorbing ability of the substance depends on its particle size, specific surface area, adsorption method, and the like. This is not an exception, as long as it is an inorganic porous material and an organic adsorbent that exhibit the above-mentioned gas adsorption ability.

The gas adsorption capacity in the present invention means that at room temperature, 1.0 g of an adsorbed substance is placed in a 130 ml closed glass container equipped with a cock and a rubber inlet for syringe injection, and the pressure is reduced by a vacuum pump. A foaming agent was injected using a syringe so that the foaming agent concentration became 1.0 vol% from the rubber injection port for syringe injection, and the cock was opened under an air atmosphere and the inside of the sealed container was brought to atmospheric pressure for 24 hours. After standing, the concentration of the foaming agent in the closed glass container was measured by using a gas chromatograph GC-14B manufactured by Shimadzu Corporation (detector: hydrogen flame ionization detector (FID), column: Chemical Inspection Association G-900,
Column temperature: 80 ° C., carrier gas: high-purity helium gas, flow rate: 30 ml / min) is used for quantitative measurement, and refers to the value calculated by the following equation. A = {[(1-B) / 100] × 0.13L} / 22.
4L where A: Gas adsorption capacity (mol / g) B: Gas concentration in closed glass container after standing for 24 hours (vo
1%) In the present invention, a synthetic resin foam packaging material, a load such as a pallet, a package or the like for storing or transporting the synthetic resin foam, and supporting or packaging the synthetic resin foam. What supports and contacts the synthetic resin foam at the time of etc. is called a synthetic resin foam support.

The shape of the adsorbent used in the present invention may be appropriately changed according to the mode of storage, transportation and the like of the synthetic resin foam. By embedding or affixing it in the synthetic resin foam support, it can be present in the accommodation space of the synthetic resin foam.

Examples of the form in which the adsorbing substance is used include those obtained by enclosing the adsorbing substance in a nonwoven fabric, paper, plastic film, or the like, or using a general-purpose high-density material such as polypropylene, polyethylene, or polystyrene. The adsorbed substance is mixed with a molecular resin and molded into various forms such as a sheet or mat, or a synthetic resin foam support formed into a sheet, pallet, glass, cylindrical, etc. An embedded or pasted form may be used. In any case, there is no particular limitation as long as the shape can coexist with the foam in the accommodation space of the synthetic resin foam.

The larger the area of contact between the adsorbed substance and the atmosphere in the space for accommodating the synthetic resin foam, the greater the adsorbability and the amount of adsorbed substance. The structure of the resin foam support is preferably a hollow structure capable of increasing the contact area between the adsorbed substance and air.

There are no particular restrictions on the location and location of these adsorbents and foam supports into which the adsorbents are inserted, but the foaming agent used for the synthetic resin foam usually has a greater specific gravity than air. Therefore, it is desirable to install it below the loaded synthetic resin foam. For example, after the adsorbing substance or the foam support into which the adsorbing substance is inserted is laid on the floor of the accommodation space, the synthetic resin foam is loaded.

These adsorbed substances can be recycled by removing the adsorbed volatile components by a treatment such as heating or decompression. By repeatedly using these adsorbed substances, the cost can be greatly reduced. Can be.

As a specific example, a method in which the adsorbed substance after transporting the foam is subjected to a heat treatment in a dry oven or a similar drying chamber to desorb the adsorbed volatile components, There are a method of desorbing the volatile component adsorbed by vapor deposition, a method of performing spray heating with steam to desorb the adsorbed gas, and then drying the gas in a drying chamber.

The amount of the adsorbing substance coexisting in the accommodation space largely depends on the properties of the adsorbing substance, especially on the adsorbing ability, and further depends on the type of the foaming agent in the foam to be stored and transported and the remaining amount of the foaming agent. considering the amount of volatile components released from the body, in the range of weight 20~2000g having an inner volume of 1 m ³ around the adsorbent material of the accommodation space, which,
A more desirable range is 50 to 1000 g.

Below this range, the amount of volatile components with respect to the amount of adsorbed substances becomes excessive, and the desired amount of adsorption cannot be obtained, so that the concentration of volatile components tends to increase. It becomes inappropriate due to an increase in cost.

Examples of the accommodation space used include a product warehouse for storage, a truck and a container used for transportation, and the like. Especially for trucks, there are so-called refrigerated cars, box cars, wing cars, open-top cars, flat body cars, etc., and the shape of the carrier is wide and there is a big difference in the degree of sealing, The present invention exerts a sufficient effect irrespective of the degree of sealing, and the present invention does not particularly limit the type of vehicle as long as the foam is usually stored and transported.

[0034]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

After placing 1.0 g of the adsorbed substance in a 130 ml closed glass container, the concentration of each foaming agent (dimethyl ether, isobutane) in the closed glass container was adjusted to 1.0 vol%, and the closed glass after being allowed to stand for 24 hours. The concentration in the container,
The measurement was performed using a gas chromatograph (detector: FID), and calculated from the reduced amount of the blowing agent.

A thermoplastic resin foam was prepared, and the amount of volatile components adsorbed from the foam was measured.

The plate-like styrene resin foam is a polystyrene resin (A & M Styrene Co., Ltd., trade name: Stylon G9401, melt index (MI): 2.0).
0.1 part of talc as a nucleating agent, 0.25 part of a water-absorbing polymer, 0.1 part of anhydrous silica, and 3.0 parts of hexabromocyclododecane as a flame retardant were added to 100 parts.
While being heated and kneaded at 200 ° C. in an extruder, a mixed foaming agent of dimethyl ether and isobutane and water were press-fitted into the mixture, and then supplied to a kneading cooler to be cooled to about 115 ° C. It was obtained by extrusion foaming through a molding die coated with a slit having a gap of 2.0 mm and a flow surface with a fluororesin.

[0038] The obtained foam was 150 mm x 100 mm
Cut 4 pieces to a size of × 25mm, length 160mm, width 1
A gas-chromatograph (detector: FID) of a foaming agent concentration in a sealed container enclosed in a sealed container made of acrylic having a height of 20 mm and a height of 110 mm with each of the adsorbing substances 1 to 10 g after 24 hours.
And the adsorption amount of volatile components was determined. Example 1 A zeolite (trade name: SILTON CPT-30, manufactured by Mizusawa Chemical Industry Co., Ltd.) was used as an adsorbing substance, and the amount of adsorption of volatile components was determined by the above method. Example 2 Activated carbon fiber (manufactured by Toyobo Co., Ltd.)
KF1500S), and the amount of volatile component adsorbed was determined by the above method. Example 3 Coconut shell activated carbon (Ajinomoto Fine Techno Co., Ltd.)
Product name: Granular activated carbon Y-4) was used to determine the amount of volatile component adsorbed by the above method. Comparative Example 1 Activated alumina (manufactured by Mizusawa Chemical Industry Co., Ltd., trade name: Activated Alumina MGA) was used as an adsorbing substance, and the amount of adsorption of volatile components was determined by the above method. Comparative Example 2 Magnesium oxide (manufactured by Kyowa Chemical Industry Co., Ltd.)
(Trade name: Micromag) was used to determine the adsorption amount of volatile components by the above method. Comparative Example 3 Activated clay (made by Mizusawa Chemical Industry Co., Ltd.)
(Galeon earth), and the adsorption amount of volatile components was determined by the above method. Comparative Example 4 The amount of volatile component adsorbed was determined by the above method without using an adsorbent.

The results obtained are shown in Table 1. Thus, the effects of the present invention were sufficiently recognized in the examples shown in the examples since the entire amount of the foaming agent in the closed container could be adsorbed.

On the other hand, from the results of Comparative Examples 1, 2, and 3, it is clear that the substances of Comparative Examples 1, 2, and 3 have an insufficient amount of adsorption, and the adsorption capacity is 3.0 × 10 ⁻⁵ mol / g or less. In this case, it can be seen that the effects of the invention cannot be obtained.

[0041]

[Table 1] Example 4 Further, the foam obtained above was 910 mm immediately after production.
Cut to dimensions of 1820 mm x 25 mm, and cured and stored in a warehouse for 24 hours, prepare a truck (loading 2
t, bed shape: box, dimensions: 4.3m × 2.0m × 2.2
m) 8.7 m of adsorbed substance (activated carbon fiber) on the floor of the bed
^{3 After} laying (about 1000 g), loading 400 foams prepared on top of it, sampling the gas in the truck bed, measuring the foaming agent concentration in the atmosphere with a gas chromatograph (detector: FID), and loading the truck bed. The reduction amount of the foaming agent in the atmosphere was determined. Comparative Example 5 The amount of the foaming agent in the atmosphere of the truck bed was determined by the above method without inserting the adsorbing substance.

The results are shown in Table 2. As a result, since the concentration of the blowing agent in the atmosphere was sufficiently lower than that of the blank, the effect of the present invention was sufficiently recognized.

[0043]

[Table 2]

[0044]

According to the present invention, when a synthetic resin foam containing a volatile component is transported and stored, an adsorbing substance and a synthetic resin foam support containing the adsorbing substance coexist in the accommodation space. As a result, there is no need to secure a storage curing period until the release of volatile components from the synthetic resin foam becomes lubricious, and the synthetic resin foam containing volatile components is safer and less expensive than conventional products. The body can be transported and stored.

Claims (8)

[Claims] 1. A synthetic resin foam characterized in that an adsorbing substance having an adsorption capacity of 3.0 × 10 ^-5 mol or more per gram is coexisted with volatile components released from the synthetic resin foam. Transport and storage methods. 2. The method for transporting and storing a synthetic resin foam according to claim 1, wherein the adsorbing substance is an inorganic porous material or an organic gas adsorbing material. 3. The synthesis according to claim 1, wherein the adsorbing substance is one or a combination of two or more selected from zeolite, activated carbon, activated carbon fiber, and high molecular polymer adsorbent. Method for transporting and storing resin foam. 4. The method for transporting and storing a synthetic resin foam according to claim 1, wherein the adsorbent is wrapped with a nonwoven fabric, paper, plastic film, or the like. 5. The method for transporting and storing a synthetic resin foam according to claim 1, wherein the adsorbent is mixed with a polymer resin to form a sheet or a mat. . 6. The method according to claim 1, wherein a pallet-shaped, saw-shaped, tubular, or sheet-shaped synthetic resin foam support on which an adsorbing substance is embedded or attached is used. Method for transporting and storing synthetic resin foam. 7. The method for transporting and storing a synthetic resin foam according to claim 1, wherein the synthetic resin foam is a thermoplastic resin foam. 8. The method for transporting and storing a synthetic resin foam according to claim 1, wherein the synthetic resin foam is an extruded polystyrene resin foam.