JPH06238795A - Thermal insulating structure - Google Patents

Abstract

PURPOSE:To shape a thermal insulating structure which can follow the shape of a heat-insulated body and can be filled into a gap part by filling synthetic resin foamed particles in a flexible plastic container with a specified oxygen permeability and reducing the gas pressure in the gap part formed in the container to a specified pressure. CONSTITUTION:Synthetic resin foamed particles are filled in a flexible plastic container with an oxygen permeability of at most 100cm<3>/sec cm<2>.cmHg and the gas pressure in the gap part formed in the container is reduced to 1-759Torr. Mutual positional displacement of foamed particles is suppresssed thereby and the whole shape of the filling material is held against the outer pressure. It is possible therefore to obtain shapability following the shape of a heat insulating body in the application, and to obtain self-standing properties as a heat insulating structure.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention can fill gaps of various shapes such as heat insulating materials, particularly valves, flanges, joints, etc. in plant piping, joists, studs, etc. in residential construction,
A hard in-mold molded heat insulating material that is shaped in a mold of a predetermined shape from a flexible heat insulating material that has on-site formability that can follow the shape of the object to be kept cold The present invention relates to a special heat insulating structure that can be provided.

[0002]

2. Description of the Related Art As a heat insulating material used for keeping heat and cold, an inorganic fiber heat insulating material such as glass wool or a hard synthetic resin foam such as hard urethane foam or polystyrene foam is usually used. Although glass wool is inferior in heat insulation performance, it is lightweight and inexpensive, so it is most commonly used.
Since it is also flexible, it is an excellent heat insulating material that can easily cut and fill gaps of various shapes.

However, during the heat insulating work, the glass fibers are scattered to irritate the operator's skin, which causes considerable discomfort. Further, after construction, it absorbs water over time due to moisture permeation to cause material corrosion of the heat-insulated body, or to cause a phenomenon such as dropping or sagging due to an increase in weight due to water absorption, which causes remarkable deterioration of heat insulation performance. Although the above drawbacks are greatly improved with synthetic resin foams, they are supplied as plate-shaped or mold-shaped products of a certain shape, so they involve cutting work at construction sites and It has drawbacks such as difficulty in filling. In addition, in-situ foaming of rigid polyurethane foam allows spraying and injecting foaming, but in the former it is difficult to fill the gap, and in the latter a formwork is required to suppress the foaming pressure, and the corners are not filled. It also happens.

The general-purpose heat insulating material as described above has a thermal conductivity of about 0.02 to 0.05 Kcal / m · h · ° C, while a smaller value of 0.005 to 0.010 Kc.
There is a powder vacuum heat insulating material showing a thermal conductivity of al / m · h · ° C. For example, as disclosed in Japanese Patent Application Laid-Open No. 2-271194, calcium silicate or pearlite powder, which is a fine powder having a particle diameter of 1 to 10000 nm, is 0.0
It is filled in a container in a high vacuum state of about 1 to 10 torr, but enormous energy is required to achieve such a high vacuum, and the airtightness of the container for maintaining a high vacuum. Since it is also required, it is limited to special applications.

Although it has a structure similar to this, but is technically completely different and does not strictly require heat insulating performance, it is disclosed in Japanese Utility Model Publication No. 4-124635 and Japanese Unexamined Patent Publication No. 1-220.
There is also a heat insulating material disclosed in Japanese Patent Publication No. 798, that is, a foamed resin strip simply packaged under atmospheric pressure. These have high thermal conductivity of 0.04 to 0.1 Kcal / m · h · ° C and are inferior in heat insulation performance, but are characterized by being inexpensive and easy to handle during construction. However, in such materials, foamed resin pieces may move in the packaging container during construction, resulting in a lack of filling parts and a significant thermal bridge, and since the material itself is not self-supporting, it does not sag or fall after construction. Occasionally, the original heat insulation may not function.

[0006]

DISCLOSURE OF THE INVENTION The present invention has improved the above-mentioned drawbacks, has the self-supporting property of the heat insulating material itself, is free from sagging and drops, and is deformable in accordance with various shapes of the heat insulation body. With the same constituent materials, from flexible heat insulators that can be shaped in the field and that can easily fill gaps to hard heat insulators that are comparable to plate-shaped or standard molded products It can be used and has a relatively low thermal conductivity of 0.0
An object of the present invention is to provide an excellent new heat insulating material showing 2 to 0.04 Kcal / m · h · ° C.

[0007]

SUMMARY OF THE INVENTION The present invention provides a synthetic resin foam strip or synthetic resin foam particles of 100 cm ³ / sec.
A heat insulating structure characterized by being filled in a flexible plastic container having an oxygen permeability of cm ² · cmHg or less, and reducing the gas pressure of the void formed inside the container to 1 to 759 torr. It is the body.

That is, in the present invention, the synthetic resin foam strips or synthetic resin foam particles are filled in the space closed from the external system of the flexible plastic container, and the pressure in the void in the space is removed. By adjusting the pressure to be lower than atmospheric pressure, it is possible to suppress the positional fluctuation between the filled foam strips or the expanded particles and to keep the overall shape of the filling material against the atmospheric pressure. It is the body.

Generally, a plastic material has a property of permeating a gas if there is a pressure difference, so that there is a problem that the pressure difference between the inside and the outside of the plastic container disappears with time. Therefore, it is important to consider the gas permeability as the material of the container. Specifically, air permeates from the atmosphere into the container, the internal pressure of the container becomes equal to the atmospheric pressure due to the change with time after manufacturing, and the function immediately after manufacturing is lost. As a result, the foam pieces or the foamed particles are likely to move, resulting in problems such as missing filling portions and lack of independence. Therefore, it is necessary to select the plastic container material from the viewpoint of its gas permeability, and to maintain the function of the original design for a necessary period, and the oxygen permeability of the plastic container material is 10 in the standard state (STP).
It should be 0 cm ³ / sec · cm ² · cmHg or less.

Oxygen permeability is 100 cm ³ / sec · cm
^{If the} pressure exceeds ² cmHg, the internal pressure of the container during manufacturing will be 1 torr.
Even if it is below, it will reach atmospheric pressure in a few months,
It is a problem for practical use. In order to keep the internal pressure of the container below atmospheric pressure for a long period of time, the oxygen permeability of the preferred container material is preferably 50 cm ³ / sec · cm ² · cmHg or less.

The container is a film made of various plastic materials, a laminate material made of such plastic film and metal foil, a plastic film having a vapor deposition film formed on the surface, or two or more kinds made of different kinds of plastic materials. A bag that has a gas barrier property and is deformable, such as a multilayer film, is used. Further, the thickness of the film material can be set in consideration of the gas permeability of the material.

In the case of a single plastic film, the oxygen permeability is 100 cm ³ / sec · cm ² · cmH.
The film thickness (μm) that is less than or equal to g is described for reference. Polyacrylonitrile (0.02), cellophane (0.21), nylon 66 (0.3), polyvinylidene chloride (0.5
3), nylon 6 (3.8), rigid polyvinyl chloride (4.5), crystalline polyethylene terephthalate (3.
5), amorphous polyethylene terephthalate (5.9),
There are high-density polyethylene (40.3), low-density polyethylene (288), polypropylene (230) and the like, but when used as a low temperature cold insulating material, low moisture permeability is desired. There is no problem with a laminate material with a metal foil, but a hydrophobic resin material is preferable for a resin film.

In fact, a film material which is supplied as a bag and which is easily adhered is preferable in order to maintain airtightness by sealing with synthetic resin foam strips or foamed particles and then heat sealing or the like. Specific examples of the multilayer film include polyvinylidene chloride / adhesive layer / polyolefin,
Polyvinyl chloride / Adhesive layer / Polyolefin, Nylon /
Adhesive layer / polyolefin, PET / adhesive layer / polyolefin, cellophane / adhesive layer / polyolefin, ethylene vinyl alcohol copolymer / adhesive layer / polyolefin,
Nylon / adhesive layer / polyvinylidene chloride / adhesive layer / polyolefin, nylon / adhesive layer / cellophane (or ethylene vinyl alcohol copolymer) / adhesive layer / polyolefin, nylon / adhesive layer / cellophane (or ethylene vinyl alcohol copolymer) / Polyvinylidene chloride (or polyvinyl chloride) / Adhesive layer / Polyolefin,
Polyolefin / adhesive layer / cellophane (or ethylene vinyl alcohol copolymer) / adhesive layer / polyolefin, polyvinylidene chloride (or polyvinyl chloride) / adhesive layer / cellophane (or ethylene vinyl alcohol copolymer) / adhesive layer / polyolefin, Ionomer / adhesive layer / cellophane (or ethylene vinyl alcohol copolymer) / adhesive layer / polyolefin, polyolefin /
Adhesive layer / polyvinylidene chloride (or polyvinyl chloride)
There are multilayer films such as / adhesive layer / polyolefin.
Here, polyolefin refers to polyethylene, polypropylene, and ethylene-vinyl acetate copolymer. Further, the adhesive layer is constituted as required, but an ethylene vinyl acetate copolymer is generally used. A metal foil or a metal vapor deposition film may be formed between these layers.

There is no particular limitation on the kind of the synthetic resin foam strip or the synthetic resin foam particles constituting the present invention, and a resin such as polyurethane, polystyrene, polyethylene, polypropylene, polyester, vinylidene chloride copolymer is foamed. Ordinary ones can be used. These are used in the form of spherical foamed particles formed as a granular foam or in the form of a cut piece of a molded body. The size of the particles or particles is preferably about 0.5 to 5 mm in diameter.

Spherical expanded particles are desirable from the viewpoint of increasing the filling rate in the container and being capable of forming various shapes on site. The heat insulating performance of the heat insulating structure of the present invention depends largely on the heat insulating performance of the synthetic resin foam, and is therefore selected according to the purpose of use. When low thermal conductivity is required, a small piece of rigid polyurethane foam showing low thermal conductivity in the foam alone, or a vinylidene chloride resin foamed particle containing a fluorocarbon gas of low thermal conductivity inside the foam. Those are preferable.

Further, the air existing in the void in the container is
Since it is necessary to make the porosity as low as possible in order to increase the thermal conductivity of the heat insulating structure, the most preferable one is a spherical particle that can be most closely packed in a constant volume, usually 30 to 40. A spherical expanded particle having a porosity of 10% is preferable. Among them, vinylidene chloride resin foamed particles having a low thermal conductivity of the foamed particles themselves are unprecedented, and a low thermal conductivity of 0.020 to 0.024 kcal / m · h · ° C can be achieved as a heat insulating structure.

The vinylidene chloride resin foamed particles in the present invention are composed of vinylidene chloride and at least one vinyl monomer copolymerizable therewith, and vinylidene chloride is 3
It is obtained by heat-foaming expandable resin particles obtained by containing an organic volatile foaming agent in an amorphous vinylidene chloride copolymer resin containing 0% by weight or more and having a glass transition point of 85 ° C. or more. . Specifically, for example, JP-A-63
-170433, JP-A-63-170434 and JP-A-63-170435 can be used.

Further, the surface of the filling material may be treated with a radiation preventive agent for suppressing heat conduction due to radiation to improve the heat insulating performance. As radiation inhibitors, carbon black, graphite, cordierite, diatomaceous earth, calcium silicate, SiC, TiO ₂ , ZrO, Cr
Examples include fine particles of O ₃ , SiO ₂ , Al ₂ O ₃ , CoO, CaO and the like, metal powder, metal foil and the like.

The depressurized state of the voids formed inside the container in the present invention is preferably 1 to 759 torr. If it is less than 1 torr, it becomes a high vacuum state and there is a problem in manufacturing a heat insulating material or maintaining airtightness.
Further, the size of the voids formed between the particles of the foam strip or the expanded particles is much larger than the mean free path of the gas such as air under the pressure, and the heat insulation performance such as the vacuum powder heat insulating material can be obtained. It is not required and is not intended by the invention. A more preferable lower limit of the reduced pressure state is about 100 torr for ease of production.

When the depressurized state exceeds 759 torr, the gas pressure inside the container becomes equal to the atmospheric pressure, and the positional relationship between the synthetic resin foam fine particles or the foamed particles filled inside is easy to change and can flow freely. Therefore, the self-supporting property of the heat insulating structure and the on-site formability following the shape of the heat insulation object, which are the objects of the present invention, are lost. In the present invention, the depressurized state inside the container plays a very important role. For example, in a depressurized state of about 700 to 759 torr, the synthetic resin foam strips and expanded particles that are the filler do not flow freely, but the mutual positional relationship can be changed by an external force, If you remove the external force, you can maintain the deformed state, give the site shapeability that follows the shape of the heat insulation body, and also have the self-supporting property as a heat insulating structure,
No sagging or dropping after construction.

The reduced pressure inside the container is 1 to 700 torr.
In a relatively high decompressed state, it is difficult for the synthetic resin foam strips or expanded particles to move relative to each other, and the same quality as a regular hard foam insulation material having a uniform shape can be obtained. As one aspect of the present invention, by utilizing gas movement inside and outside the foamed particles of closed cells, it has flexibility at the time of construction and can be easily shaped in the field, and is left in a shaped state according to the shape of the heat insulation body. As a result, it is possible to provide a heat insulating structure in which the shape of the heat insulating structure is changed to a molded product of the same quality as the rigid hard foam insulating material in which the positional variation between the expanded particles in the container is unlikely to occur while the shape is maintained. This is a characteristic usage that makes good use of the following principle.

Generally, the gas forming the inside of the bubbles of the foamed particles consisting of the closed cells immediately after the foaming resin particles containing the organic volatile foaming agent is foamed by heating is only the foaming agent gas and does not contain air. Since the partial pressure is zero, the air invades into the closed cells of the expanded particles from the atmosphere outside the expanded particles over time, and the partial pressure of the air becomes equal to the atmospheric pressure.

Therefore, if the expanded particles are filled and sealed in a container having a gas barrier property before the air partial pressure inside the expanded particles becomes equal to the atmospheric pressure, the voids existing between the expanded particles in the container will be formed. The constituent air is taken into the inside of the expanded particles, and the voids are in a reduced pressure state. Therefore, it is possible to provide a heat insulating structure having the property of initially having flexibility but having rigidity over time.

In order to effectively utilize such characteristics, there is a problem in production and handling in the resin foamed particles having the property that the gas movement inside and outside the foamed particles is completed in a short time as described above, and the above gas movement is slow. It is preferably achieved. From this point of view, vinylidene chloride resin foamed particles made of a material having low gas permeability and containing fluorohydrocarbon as a foaming agent are preferable as the expandable resin particles.

The gas that occupies the voids inside the container in the present invention is generally air, but it is preferable to fill it with a gas having a lower thermal conductivity than that of air in order to improve the heat insulating performance. Freon-based compounds such as fluorinated hydrocarbons and chlorinated fluorinated hydrocarbons are preferable as the gas having a thermal conductivity smaller than that of air.

[0026]

EXAMPLES The present invention will be described below with reference to examples. The evaluation method used in the present invention is as follows. [Oxygen permeability]: According to ASTM D1434-7, the oxygen permeability in a standard state (STP) is obtained using a gas permeation measuring device (Toyo Seiki Seisakusho).

[Thermal conductivity]: Measured according to JISA1412. [Bulk Density of Expanded Particles]: Pre-expanded particles aged for 24 hours in a temperature-controlled room at 25 ° C. after foaming were used in a measuring cylinder to
Collect liters, measure the weight, and obtain the bulk density. The average value of 5 measurements is adopted.

[Independence]: 50 × 1000 × 10
When a heat insulating structure with a size of 00 mm is erected vertically on the floor so that the direction of the length of 10 mm is vertical, and the entire 500 mm height from the floor of both sides is gripped, the inside of the container is composited. When there is no positional change between the resin foam strips or the expanded particles and the deflection of the heat insulating structure is within a deflection angle of 30 ° from the vertical direction, it is determined to be self-supporting.

[Formability on site]: A plate-shaped heat insulating structure was bent and sandwiched between T-shaped joints having a 2B pipe diameter and lightly pressed from both sides manually. It is judged that there is a site-shaped property when the T-shaped pipe comes into close contact with the T-shaped pipe, deformation corresponding to the shape occurs, the thickness of the heat insulating material after the deformation is substantially uniform, and the lack filling portion does not occur.

[Rigidity]: When the bending elastic modulus (JIS A9511) of the heat insulating structure is 5 kg / cm ² or more, and the positional relationship between the synthetic resin foam pieces or the foamed particles inside the container does not shift due to finger pressure. Determined to be rigid.

[0031]

Example 1 As a container, high density polyethylene (HDP
E), nylon-6, and vinylidene chloride-vinyl chloride copolymer (PVDC) used as a single body material (size 50 × 1000 × 1000 mm), and as a foamed particle, a bag body having a size of 50 × 1000 × 1000 mm was used. After filling with vinylidene chloride resin foam particles (made by Asahi Kasei Kogyo Co., Ltd., trade name: Cellmore) having a bulk density of 5 to 5.0 mm listed in Table 1, the pressure inside the container is reduced to the pressure listed in Table 1 and sealed. Each was sealed to obtain a heat insulating structure.

The film thickness (μm) of the container bag, the oxygen permeability (cm ³ / sec · cm ² · cmHg, STP), immediately after the production of the heat insulating structure, 100 days after the production, and 10
Table 1 shows the pressure inside the container after 00 days, the evaluation results of the self-supporting property, the site formability, and the rigidity of the heat insulating structure at that time, and the value of the thermal conductivity after 100 days.

[0033]

Comparative Example 1 A heat insulating structure was manufactured and evaluated in exactly the same manner as in Example 1 except that the container material was changed to 200 μm thick low density polyethylene (LDPE). The results are also shown in Table 1.

[0034]

Example 2 As a container material, a bag made of vinylidene chloride-vinyl chloride copolymer (size 50 × 1000 × 10
00 mm) was used to fill the bag with the expanded particles listed in Table 2 and the crushed pieces of the foam, and then the internal pressure of the container was reduced to the pressure shown in Table 2 and hermetically sealed to form the heat insulating structure. Obtained. The evaluation results are also shown in Table 2.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

INDUSTRIAL APPLICABILITY The heat insulating structure of the present invention is capable of tracking the shapes of various types of heat-insulated objects to be kept warm, from flexible and self-supporting heat insulators that can be filled into gaps to fixed hard heat insulators. It can be provided arbitrarily, and is particularly suitable as a heat insulating structure having excellent shapeability on site.

Claims (1)

[Claims] 1. A synthetic resin foam strip or synthetic resin foam particles is filled in a flexible plastic container having an oxygen transmission rate of 100 cm ³ / sec · cm ² · cmHg or less, and formed inside the container. The gas pressure in the void is 1 to
A heat insulating structure characterized by being decompressed to 759 torr.