JP2008008431A - An integrally molded composite heat insulating material comprising a vacuum heat insulating material and expanded polystyrene and a method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite heat insulating material comprising expanded polystyrene and a vacuum heat insulating material, and having a high cover ratio and high strength. <P>SOLUTION: This composite heat insulating material comprising a vacuum heat insulating material 1 and expanded polystyrene 5 can be provided by foaming and molding foamable polystyrene particles in a die wherein a vacuum heat insulating material with a hot melt-based adhesive 6 applied to the surface thereof is arranged, or foaming and molding foamable polystyrene particles in a die where a vacuum heat insulating material having a through-hole and/or a cutout part is arranged. The expandable polystyrene may cover the whole surface of the vacuum heat insulating material, or may cover a part thereof. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a thermal insulation device such as a refrigerator and a cold car, and a composite heat insulating material used as a heat insulating material for floors and walls of buildings.

Insulating materials are used for heat insulation and cold insulation equipment such as refrigerators and cold insulation vehicles, and floors and walls of buildings in order to block heat transfer. Conventionally, as a heat insulating material, an aluminum plate bonded to both surfaces of a heat insulating material made of hard urethane foam or the like has been used (see Patent Document 1).
However, for example, heat insulating materials used in cold cars and refrigerators are required to improve heat insulating performance from the viewpoint of energy saving, but when using hard urethane foam as a heat insulating material, the heat insulating material is required to increase the heat insulating performance. Therefore, there is a problem that the storage capacity is reduced and the fuel consumption is also deteriorated because the weight is increased.

  Patent Documents 2 and 3 disclose a composite heat insulating material having a structure in which a vacuum heat insulating material 1 is embedded in a heat insulating material made of hard urethane foam 8 as shown in FIG. ing. 6A is a plan view, and FIG. 6B is an EE cross-sectional view of FIG. 6A. However, since rigid urethane foam is poorly recyclable, it is disposed of when it is used. However, rigid urethane foam is not suitable for landfilling, and there is a problem that harmful gas is generated when incinerated. .

In Patent Document 4, when the expanded polystyrene which is a material having heat insulation properties is used, it is dissolved by contacting with limonene to recover styrene, and styrene can be reused as a raw material. It has been proposed to use expanded polystyrene instead of the rigid urethane foam described in Documents 2 and 3.
The device described in Patent Document 4 is shown in FIG. Fig.7 (a) is a top view, FIG.7 (b) is FF sectional drawing of Fig.7 (a).

  By the way, for example, a heat insulating material constituting a luggage compartment of a cold car is required to have high bending strength and impact strength as well as heat insulating performance. However, as in the heat insulating material described in Patent Document 4, the vacuum heat insulating material 1 and polystyrene foam are used. 5 is integrally formed, the mechanical strength of the heat insulating material becomes weak because the vacuum heat insulating material 1 and the polystyrene foam 5 are not bonded. For this reason, in the thing of patent document 4, in order to give intensity | strength to the vacuum heat insulating material 1, the columnar part (refer FIG. 7A) of the predetermined width L of the polystyrene foam 5 is provided in the outer peripheral part of the vacuum heat insulating material 1. FIG. In addition, the foamed polystyrene 5 has a predetermined thickness D (see FIG. 7A) also in the thickness direction of the heat insulating material.

  However, if such a columnar portion is provided, the ratio of the area of the vacuum heat insulating material to the area of the heat insulating material (hereinafter referred to as “cover ratio”) is lowered, and the heat insulation performance is lowered, and the thickness is increased and the volume is increased. There is a problem, and it is necessary to divide the vacuum heat insulating material into a plurality of parts, so that there is a problem that the workability in the manufacturing process is deteriorated and the cost is increased.

JP-A-7-102655 Japanese Patent Laid-Open No. 10-114245 Japanese Patent Laid-Open No. 10-211985 JP 2005-188714 A

  An object of the present invention is to provide a composite heat insulating material comprising a polystyrene foam and a vacuum heat insulating material and having a high coverage and high strength.

As a result of diligent research to solve the above problems, the present inventors bonded a vacuum heat insulating material and a foamed polystyrene with a hot melt adhesive, thereby reducing the composite heat insulation without reducing the coverage of the vacuum heat insulating material. The present invention was completed by finding that the strength properties of the material can be improved.
That is, this invention is a composite heat insulating material as described below, and its manufacturing method.

(1) A vacuum heat insulating material and polystyrene foam obtained by foam molding of foamable polystyrene particles on at least one surface in a mold having a vacuum heat insulating material coated with a hot melt adhesive on the surface. Composite heat insulating material that is bonded by an agent.
(2) The composite heat insulation according to (1) above, wherein the vacuum heat insulating material has a through hole and / or a notch, and foamed polystyrene is formed in the through hole and / or the notch. Wood.
(3) A composite heat insulating material comprising a vacuum heat insulating material having a through hole and / or a notch, an outer surface of the vacuum heat insulating material, and a foamed polystyrene foam-molded in the through hole and / or the notch.
(4) The composite heat insulating material according to any one of (1) to (3), wherein the vacuum heat insulating material is a plate-like body.
(5) The composite heat insulating material according to any one of (1) to (4), wherein the entire surface of the vacuum heat insulating material is covered with expanded polystyrene.
(6) The composite heat insulating material according to any one of (1) to (4), wherein a part of the surface of the vacuum heat insulating material is covered with expanded polystyrene.
(7) A method for producing a composite heat insulating material comprising a vacuum heat insulating material and expanded polystyrene,
A step of pre-foaming raw material particles to form expandable polystyrene particles, a step of applying a hot-melt adhesive to the surface of the vacuum heat insulating material,
Installing the vacuum insulation material in a mold;
Filling the mold with expandable polystyrene particles,
A method for producing a composite heat insulating material, comprising: sealing a mold and steam heating to foam polystyrene particles inside the mold to form a composite heat insulating material; and demolding the composite heat insulating material from the mold.
(8) A method for producing a composite heat insulating material comprising a vacuum heat insulating material and expanded polystyrene,
A step of pre-foaming raw material particles to form expandable polystyrene particles, a step of installing a vacuum heat insulating material having a through hole and / or a notch in a mold,
Filling the mold with expandable polystyrene particles,
A method for producing a composite heat insulating material, comprising: sealing a mold and steam heating to foam polystyrene particles inside the mold to form a composite heat insulating material; and demolding the composite heat insulating material from the mold.

The composite heat insulating material of the present invention has the effects described below.
-Since the vacuum heat insulating material and the expanded polystyrene are bonded by a hot melt adhesive, the coverage of the vacuum heat insulating material can be increased and the strength properties can be improved. Moreover, even if the polystyrene foam is integrally formed only on one surface of the vacuum heat insulating material, the vacuum heat insulating material and the polystyrene foam are not easily detached, and there is no gap between the vacuum heat insulating material and the polystyrene foam even for a complicated shape.
・ By providing through holes and notches in the vacuum heat insulating material and connecting the upper and lower surfaces of the composite heat insulating material with polystyrene foam, the coverage of the vacuum heat insulating material can be increased and the strength properties can be further improved. Warpage can be reduced.
By providing through holes and notches in the vacuum heat insulating material and connecting them with foamed polystyrene on the upper and lower surfaces of the composite heat insulating material, it is possible to increase the degree of design freedom for piping and wiring while maintaining a certain degree of bending strength even without hot melt. It becomes possible.
In the composite heat insulating material of the present invention, since the vacuum heat insulating material and the expanded polystyrene are bonded, air convection between the vacuum heat insulating material and the expanded polystyrene is reduced, and the heat insulating performance is excellent.
Since the hot-melt adhesive used in the present invention is a thermoplastic adhesive, it is not necessary to perform foam molding immediately like a reaction-curable adhesive after performing an adhesion treatment on the surface of the vacuum heat insulating material. It is possible to stack and hold horizontally, which is impossible with adhesive type adhesives.

The composite heat insulating material of the present invention comprises a vacuum heat insulating material and expanded polystyrene.
The composite heat insulating material of the present invention can be used in various shapes, but in the following, it is used for a heat insulating panel, a freezer, a refrigerator, a cold car, a container, a heat and cold box, a floor / ceiling / wall of a building, a bath lid, etc. The present invention will be described by taking a flat plate type composite heat insulating material as an example.

  FIG. 1 is a view showing an example of the composite heat insulating material of the present invention, FIG. 1 (a) is a plan view thereof, and FIG. 1 (b) is a cross-sectional view taken along line AA of FIG. In this example, the vacuum heat insulating material 1 is embedded in the expanded polystyrene 5, and both are bonded at a hot melt bonding portion 6.

  The vacuum heat insulating material 1 will be described later in detail, but as shown in FIG. 2, the peripheral edge portion of the outer covering material 2 wrapping the core material 3 is in a state of being heat-sealed with the heat welding portion 4 At the time of integral molding, the peripheral edge portion is folded and taped to the upper surface or the lower surface of the vacuum heat insulating material, so that it is shown as a rectangular parallelepiped shape in the drawing.

The composite heat insulating material having the structure as shown in FIG. 1 can be manufactured by a manufacturing method including the following steps, for example.
(1) A step of pre-foaming raw material particles to form expandable polystyrene particles (2) A step of heating and melting a hot-melt adhesive and applying it to the surface of a vacuum heat insulating material (3) The vacuum heat insulating material as a mold Step of installing (4) Step of filling the mold with expandable polystyrene particles (5) Step of forming the composite heat insulating material by foaming the polystyrene particles inside the mold by sealing and heating the mold with steam ( 6) Demolding the composite insulation from the mold

In the step (3), it is preferable that the peripheral portion of the vacuum heat insulating material is folded and the folded portion is fixed with a tape or the like before the vacuum heat insulating material is put into the mold. Moreover, although it is not necessarily required to fold, in order to make the adhesion state of a vacuum heat insulating material and a polystyrene foam favorable, it is more preferable to fold. When integrally molding foamed polystyrene only on one side, it is preferable that the folding of the peripheral portion is located on the side of foamed polystyrene.
In the step (4), the hot-melt adhesive applied to the surface of the vacuum heat insulating material is melted, and the foam-formed polystyrene and the vacuum heat insulating material are bonded to each other by the hot-melt adhesive.

A hot melt adhesive is an adhesive that is in a solid state at normal temperature, and is applied to an adhesive surface with fluidity as a melted state by heating, and solidifies and adheres by cooling after application. .
Examples of the material of the hot melt adhesive used in the present invention include ethylene-vinyl acetate copolymer (EVA), polyamide (PA), and polyolefin copolymer (PP), and the softening point is 80 to 170 ° C. Are preferred. More preferably, it is EVA type or PP type, and the softening point is 100 ° C to 140 ° C.
The coating thickness of the hot melt adhesive on the surface of the vacuum heat insulating material is preferably 100 to 200 μm. If the coating thickness is too thin, good adhesive force cannot be obtained, and if the coating thickness is too thick, the filling property of the expandable polystyrene particles is poor and a good composite heat insulating material cannot be obtained. Moreover, when the thickness of an adhesive agent becomes thick, there exists a possibility of leading to the deterioration of heat insulation performance.

As the vacuum heat insulating material 1, known materials can be used. For example, as shown in FIG. 2, the core material 3 is an outer cover made of two gas barrier films having a heat-welding layer larger than the core material 3. The material is sandwiched between the materials 2 and 2 ', and the heat-welded layer is heat-sealed at the laminated portion of the outer covering materials 2 and 2' around the core material 3 under reduced pressure, and then (mechanically) heated by no pressure, heating, etc. What formed the welding part 4 and was sealed can be used.
It is preferable to use a vacuum heat insulating material having a compressive strength of 0.05 N / mm ² or more (100 ° C.).

  As the core material 3, hard plastic foam having open cells (eg, urethane foam, phenol foam, etc.), inorganic fiber (eg, glass fiber, alumina fiber, silica alumina fiber, silica fiber, etc.) and inorganic powder (eg: Dry silica, wet silica, perlite, etc.) can be used.

  Further, as the gas barrier film, for example, a composite plastic laminate film formed by laminating a heat welding layer, a metal foil and another plastic film can be used, and a metal or inorganic vapor deposition film can be used instead of the metal foil. Can be used.

As the outermost film of the gas barrier film, a film having a melting point (preferably 100 ° C. or higher) higher than the melting temperature of the hot melt adhesive is used. More preferably, one having a temperature of 120 ° C. or higher is used.
Examples of composite plastic laminate films include four-layer laminate films of polyethylene terephthalate film / nylon film / aluminum foil / polyethylene film (thermal welding layer) and polyethylene terephthalate film / aluminum foil / high-density polyethylene film (thermal welding layer). ) Of a three-layer structure.
As the polyethylene film of the heat-welding layer, the above-mentioned high-density polyethylene (HDPE) can be used, and CPP, expanded polypropylene (OPP), polyvinylidene chloride (PVDC), polyvinyl chloride (PVC) can be used instead of the polyethylene film. , Ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol copolymer (EVOH), and the like can be used.

  The particle diameter of the expandable polystyrene particles can be controlled by pre-foaming the raw material particles by changing the heating temperature and time. The particle shape of the expandable polystyrene particles is greatly related to the thickness with which the particles are filled, and is preferably 0.5 to 3.0 mm. More preferably, when the thickness for filling the expandable polystyrene particles exceeds 5.0 mm, the particle size is 1.6 mm to 3.0 mm, and when the filling thickness is as thin as 5.0 mm or less, the particle size is 0.5. It is better to use ~ 1.6mm. By making such a numerical range, the filling property of the expandable polystyrene particles can be improved, the density variation caused by forcibly pushing the particles can be prevented, and the predetermined thickness of the vacuum heat insulating material can be maintained. It becomes possible to have performance. The expansion ratio of the expanded polystyrene is preferably 15 times or more and 50 times or less. More preferably, it is 20 times or more and 30 times or less. By setting it as such a numerical value range, the strength and the heat insulation performance are balanced.

  FIG. 3 is a view showing another example of the composite heat insulating material of the present invention, FIG. 3 (a) is a plan view thereof, and FIG. 3 (b) is a sectional view taken along line BB of FIG. In this example, the vacuum heat insulating material 1 is embedded in the expanded polystyrene 5 with one side exposed. In manufacturing, a hot melt adhesive is applied to a surface other than the exposed surface of the vacuum heat insulating material and placed in a mold, and foamed polystyrene particles are filled on the coated surface side to perform foam molding. Although the vacuum heat insulating material 1 is in a state where one side is exposed, since the vacuum heat insulating material 1 and the expanded polystyrene 5 are bonded by the hot melt bonding portion 6, they are not peeled off.

The example shown in FIG. 4 is an example in which a through-hole is provided in a vacuum heat insulating material and integrally molded with foamed polystyrene and a mold, FIG. 4 (a) is a plan view thereof, and FIG. 4 (b) is FIG. It is CC sectional drawing of a). In this example, a vacuum heat insulating material coated with a hot melt adhesive is embedded in the expanded polystyrene 5. By providing such a through hole, the upper and lower surfaces of the composite heat insulating material are connected to each other by integral foamed polystyrene, so that the strength is improved and the warpage is reduced. By making the shape of the through hole uneven as illustrated, the bond between the vacuum heat insulating material and the expanded polystyrene becomes stronger. Moreover, the connection state of a vacuum heat insulating material and a polystyrene foam can be made favorable also by providing a notch part instead of providing a through-hole in a vacuum heat insulating material.
Furthermore, the strength of the composite heat insulating material can be further improved by applying a hot-melt adhesive to the through holes and notches.

  5 is a modification of that shown in FIG. 4, FIG. 5 (a) is a plan view thereof, and FIG. 5 (b) is a DD cross-sectional view of FIG. 5 (a). In the case shown in FIG. 5, the vacuum heat insulating material 1 provided with through holes is integrally molded with the expanded polystyrene 5 in a mold without applying a hot melt adhesive. By providing the through holes in the vacuum heat insulating material 1, the vacuum heat insulating material 1 and the expanded polystyrene are physically bonded to each other, so that the combined state of both is formed without using a hot melt adhesive. Strength increases. Further, the vacuum heat insulating material and the expanded polystyrene can be provided with a mechanically coupled state by providing a cutout portion instead of providing the through hole in the vacuum heat insulating material.

This type of composite heat insulating material can be manufactured by a manufacturing method comprising the following steps.
(1) Step of pre-foaming raw material particles to form expandable polystyrene particles (2) Step of installing a vacuum heat insulating material having through holes and / or notches in a mold (3) Using expandable polystyrene particles as a mold Step of filling (4) Step of forming a composite heat insulating material by foaming polystyrene particles inside the die by sealing the mold and heating with steam (5) Step of demolding the composite heat insulating material from the mold

In the above description, the flat plate type composite heat insulating material has been described, but the composite heat insulating material of the present invention can be used in various shapes depending on the application.
For example, what integrally formed the vacuum heat insulating material and the expanded polystyrene in the box shape can be used as a heat insulation box and a cooler box.
What is integrally formed into a disk shape and a cylindrical shape can be used as a cylindrical container / lid such as a hot water storage tank, a piping cover, and a cold insulated water bottle.
What is integrally formed into a semi-cylindrical shape can be used as a constituent member of a cylindrical container such as a hot water storage tank, a piping cover, and a cold insulated water bottle.
Those having a pyramid shape such as a triangular pyramid, a quadrangular pyramid, and a cone can be used as the end plate of a cylindrical container such as a hot water storage tank, a tank lorry, and a cold and warm water bottle.
Further, the polystyrene foam may be integrally formed on the entire surface of the vacuum heat insulating material or may be integrally formed only on a part of the surface.

First, preparation methods and test methods of samples prepared in Examples and Comparative Examples will be described.
<VIP and VIP polystyrene dimensions>
-VIP size: 4.6t x 70 x 90 (mm)
-VIP polystyrene size: 10t x 90 x 120 (mm)
<Sample preparation / test method>
(1) Raw material particles (particle size 0.8 mm) are pre-expanded to form expandable polystyrene particles (particle size 1.5 mm).
(2) VIP is produced.
(3) Apply hot melt to VIP.
(4) VIP is installed on the lower surface of the mold, and expandable polystyrene particles are arranged on the VIP surface excluding the surface in contact with the mold.
(5) The mold is steam-heated (about 120 ° C.), and the VIP is integrally formed with the expanded polystyrene.
(6) Sampling to bend test sample size.
(7) A bending test is performed by a method according to the bending test (JIS K 7221-2).
The adhesion was evaluated based on the ease of removal of the VIP after integral molding.

[Examples 1 to 3]
Samples of Examples 1 to 3 as shown in FIG. 3 were prepared using the hot melt agent shown in Table 1, and the adhesiveness and bending strength of the obtained samples were evaluated. The evaluation results are shown in Table 1.
[Example 4]
A VIP provided with two through-holes (hole diameter: 10 mm) as shown in FIG. 5 was produced, and a polystyrene foam was integrally formed using the VIP without using a hot-melt adhesive.
[Comparative Examples 1 and 2]
A sample was prepared and evaluated in the same manner as in Example 1 except that the adhesive shown in Table 1 was used instead of the hot melt adhesive. The evaluation results are shown in Table 1.
[Comparative Example 3]
A sample was prepared and evaluated in the same manner as in Example 1 except that the hot melt adhesive was not used. The evaluation results are shown in Table 1.

As shown in Table 1, all of the samples of Examples 1 to 3 can be stacked and held sideways, and are re-fused and bonded by steam heating (about 120 ° C.) during integral molding, and bent. Strength is improved.
(However, PA types generally have many types with a high softening point (120 to 180 ° C.), and some are difficult to re-fuse.)
In addition, since the sample of Example 4 does not use a hot melt adhesive, it can be stacked and held sideways, and since a through hole is provided in the VIP, the foamed polystyrene and VIP can be used without using the hot melt adhesive. It becomes difficult to come off.

On the other hand, the one using the acrylic adhesive of Comparative Example 1 is sticky after application of the adhesive, so it is unsuitable for stacking and holding, and the VIP surface is sticky even when integrally molded. As a result, the flowability of the expandable styrene particles is poor and an unfilled portion is formed, and the density of the VIP surface is increased.
In the case of using an epoxy adhesive as in Comparative Example 2, since the adhesive is a reaction curing type, the storage state after application is poor. That is, it must be integrally formed immediately after application.
Further, even if the adhesive is cured and then integrally molded with the polystyrene foam, the reaction is completed, the adhesive is not adhered, and the VIP is easily detached.
In the case where no adhesive is used as in Comparative Example 3, VIP is not bonded to the polystyrene foam, so that VIP is easily detached and bending strength is low.

  The composite heat insulating material of the present invention is excellent in heat insulating performance because the present invention is composed of expanded polystyrene and a vacuum heat insulating material, and the expanded polystyrene and the vacuum heat insulating material are bonded by a hot melt adhesive. Therefore, since it is excellent in bending strength and impact strength, it can be suitably used as a heat insulating material for heat insulation and cold insulation equipment such as a refrigerator and a cold car and a building.

It is a figure which shows an example of the structure of the composite heat insulating material of this invention. It is a figure which shows the structure of the vacuum heat insulating material used by this invention. It is a figure which shows the other example of the structure of the composite heat insulating material of this invention. It is a figure which shows an example of the structure of the composite heat insulating material using the vacuum heat insulating material which provided the through-hole of this invention. It is a figure which shows the other example of the structure of the composite heat insulating material using the vacuum heat insulating material which provided the through-hole of this invention. It is a figure which shows the example of the structure of the conventional composite heat insulating material. It is a figure which shows the example of the structure of the conventional composite heat insulating material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum heat insulating material 2, 2 'jacket material 3 Core material 4 Thermal welding part 5 Expanded polystyrene 6 Hot-melt-adhesion part 7 Columnar part 8 Hard urethane foam

Claims (8)

  Vacuum insulation material and polystyrene foam bonded by hot melt adhesive, obtained by foaming polystyrene foam on at least one side in a mold with a vacuum insulation material coated with hot melt adhesive on the surface. A composite heat insulating material.   2. The composite heat insulating material according to claim 1, wherein the vacuum heat insulating material has a through hole and / or a notch, and foamed polystyrene is formed in the through hole and / or the notch.   A composite heat insulating material comprising a vacuum heat insulating material having a through hole and / or a notch, an outer surface of the vacuum heat insulating material, and foamed polystyrene foam-molded in the through hole and / or the notch.   The composite heat insulating material according to any one of claims 1 to 3, wherein the vacuum heat insulating material is a plate-like body.   The composite heat insulating material according to any one of claims 1 to 4, wherein the entire surface of the vacuum heat insulating material is covered with expanded polystyrene.   The composite heat insulating material according to any one of claims 1 to 4, wherein a part of the surface of the vacuum heat insulating material is covered with expanded polystyrene. A method for producing a composite heat insulating material comprising a vacuum heat insulating material and expanded polystyrene,
A step of pre-foaming raw material particles to form expandable polystyrene particles, a step of applying a hot-melt adhesive to the surface of the vacuum heat insulating material,
Installing the vacuum insulation material in a mold;
Filling the mold with expandable polystyrene particles,
A method for producing a composite heat insulating material, comprising: sealing a mold and steam heating to foam polystyrene particles inside the mold to form a composite heat insulating material; and demolding the composite heat insulating material from the mold. A method for producing a composite heat insulating material comprising a vacuum heat insulating material and expanded polystyrene,
A step of pre-foaming raw material particles to form expandable polystyrene particles, a step of installing a vacuum heat insulating material having a through hole and / or a notch in a mold,
Filling the mold with expandable polystyrene particles,
A method for producing a composite heat insulating material, comprising: sealing a mold and steam heating to foam polystyrene particles inside the mold to form a composite heat insulating material; and demolding the composite heat insulating material from the mold.

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