JP2016507704A - Vacuum insulation core material made of melamine resin cured foam, vacuum insulation material using the same, and method for producing the same - Google Patents

Abstract

An object of the present invention is to provide a vacuum heat insulating material capable of reducing the manufacturing unit cost compared to the case of using general glass fiber wool as a core material and excellent in long-term durability. A vacuum insulation core material made of a melamine resin cured foam having an open cell ratio of 80% or more. Moreover, the vacuum heat insulating material containing the said core material and the jacket material which vacuum-wraps the said core material, and its manufacturing method. In addition, it is preferable that the said melamine resin cured foam contains the bubble whose average particle diameter is 50 micrometers-500 micrometers, or that compressive strength is 1.2 kgf / cm2-5.0 kgf / cm2. Furthermore, it is more preferable that the melamine resin cured foam contains a three-dimensional network skeleton structure. [Selection] Figure 1

Description

  The present invention relates to a vacuum heat insulating core material made of a melamine resin cured foam, a vacuum heat insulating material using the same, and a method for producing the same.

  Vacuum insulation is generally made of an inorganic compound with low thermal conductivity and low gas generation rate, such as glass fiber, as a core material, and encloses the outside with a sealed body made of a composite plastic laminate film with excellent gas barrier properties. After depressurizing the inside, it is manufactured by heat sealing the laminated portion of the gas barrier films and used as a heat insulating material for electronic products. The glass fiber wool used as the core material of the existing vacuum insulation material is gathered from bulky glass fibers and manufactured through the thermocompression process, and then used as the core material. It was possible to ensure a heat insulation performance of 0.45 W / mK level when manufacturing the material.

  However, when glass fiber wool is used as the core material for vacuum insulation, it was possible to ensure excellent initial thermal performance. As a result, there was a problem that long-term durability decreased. On the other hand, even when glass fiber board is used as a vacuum insulation core material for a long period of time, it has the advantage of minimizing the heat transfer of gas due to the small pore diameter of the glass fiber board during gas permeation and excellent long-term durability. However, there was a disadvantage that the initial heat insulation performance was lowered.

  As a result, when glass fiber wool is used as a core material in existing vacuum heat insulating materials, it has a short life due to a decrease in long-term durability performance, and not only in the construction field requiring a life of 10 years or more. There was a problem in reliability when applied to the home appliance field. In addition, when glass fiber board is used as the core material, the manufacturing cost is high and the molding characteristics are reduced, so there is a limit to application as a heat insulating material, and there is a need for research on the core material for vacuum heat insulating material. It has increased.

None

  One embodiment of the present invention provides a core material for a vacuum heat insulating material that has a low manufacturing cost and is excellent in heat insulating performance and long-term durability performance.

  Another embodiment of the present invention provides a vacuum heat insulating material that can improve the heat insulation performance by minimizing the heat transfer path and diversify the utilization by reducing the weight of the whole.

  In one embodiment of the present invention, there is provided a core material for a vacuum heat insulating material formed of a melamine resin cured foam having an open cell content of 80% or more.

The melamine resin cured foam may include bubbles having an average particle diameter of about 50 μm to about 500 μm.
The compression strength of the melamine resin cured foam may be about 1.2 kgf / cm ² to about 5.0 kgf / cm ² .
The melamine resin cured foam may include a three-dimensional network skeleton structure.

  The skeletal structure may not include a bubble wall.

  In another embodiment of the present invention, there is provided a vacuum heat insulating material comprising: a core material formed of the melamine resin cured foam; and a jacket material for vacuum-packaging the core material.

  The vacuum heat insulating material may further include a getter material attached to or inserted into the core material and having a moisture absorption rate of about 25% or more.

  The jacket material may include a laminated structure of a surface protective layer, a metal barrier layer, and an adhesive layer from the outside.

  The surface protective layer has a layer structure of polyethylene terephthalate (PET) and nylon film, the metal barrier layer is formed of aluminum foil, and the adhesive layer includes high density polyethylene (HDPE) and low density polyethylene (LDPE). ), Linear low density polyethylene (LLDPE), unstretched polypropylene (CPP), stretched polypropylene (OPP), polyvinylidene chloride (PVDC), polyvinyl chloride (PVC), ethylene-vinyl acetate copolymer (EVA), ethylene- It may be one or more selected from the group consisting of vinyl alcohol copolymer (EVOH) and combinations thereof.

  The adhesion between the surface protective layer and the metal barrier layer and the adhesion between the metal barrier layer and the adhesive layer may be performed by a polyurethane (PU) resin, respectively.

  In still another embodiment of the present invention, a core material of the melamine resin cured foam is produced; a pressure of about 0.5 Pa to about 10 Pa is applied to the core material at a temperature of about 50 ° C. to about 250 ° C. A method for producing a vacuum heat insulating material, comprising: applying for about 10 minutes to about 200 minutes to remove residual substances; and surrounding the core material with an outer cover material and then vacuum packaging.

  The vacuum heat insulating material is advantageous in that it can save a manufacturing unit cost and is excellent in long-term durability as compared with the case where general glass fiber wool is used as a core material. Also, by minimizing the heat transfer path, the heat insulation performance becomes excellent at less than about 0.03 W / mK.

  Further, the manufacturing method of the vacuum heat insulating material prevents a decrease in the vacuum degree by minimizing the organic compound discharged from the melamine foam, and does not cause outgassing, so that the heat insulating performance is not deteriorated. In addition, a vacuum heat insulating material that can be used for at least about 10 years or more can be provided.

It is the schematic which showed the core material for vacuum heat insulating materials which concerns on one Example of this invention. It is the schematic which showed the structure of the core material for vacuum heat insulating materials which concerns on one Example of this invention. (A) And (b) is sectional drawing which showed the vacuum heat insulating material which concerns on one Example of this invention. It is sectional drawing of the jacket material contained in the vacuum heat insulating material which concerns on one Example of this invention.

  Hereinafter, embodiments of the present invention will be described in detail. However, this is provided as an example, and the present invention is not limited thereby, and the present invention is only defined by the scope of the claims to be described later.

  In order to clearly describe the present invention, portions not related to the description are omitted, and the same reference numerals are given to the same or similar components throughout the specification.

  In the drawings, the thickness is shown enlarged to clearly represent many layers and regions. In the drawings, the thickness of some layers and regions is exaggerated for convenience of explanation.

  In the following, when an arbitrary configuration is formed on the “upper (or lower)” of the substrate or the “up (or lower)” of the substrate, the arbitrary configuration is in contact with the upper surface (or lower surface) of the substrate. It is not limited to include any other configuration between the substrate and any configuration formed on (or below) the substrate.

(Vacuum insulation core material)
In one embodiment of the present invention, a core material for a vacuum heat insulating material formed of a melamine resin cured foam having an open cell ratio of 80% or more is provided.

  FIG. 1 is a schematic view showing a vacuum heat insulating material core according to an embodiment of the present invention. Referring to FIG. 1, the vacuum heat insulating material core 100 is seen to have a convex shape including a melamine resin cured foam.

  At this time, it is preferable to adjust the foaming ratio of the bubbles 110 so that the open cell ratio of the core material is about 80% or more. The open bubble rate defines the fraction of open bubbles among the bubbles formed in a unit area. In the present invention, when the open bubble rate is less than 80%, the subsequent vacuum process time is long. In addition, the residual gas remains inside the melamine resin cured foam, which can cause gas release that occurs after formation of the vacuum insulation.

  On the other hand, when the open cell ratio is 100%, the structural strength is remarkably reduced and the vacuum pressure cannot be withstand, so the lower limit of the open cell ratio is less than 100%. At this time, the open cell ratio may be measured by ASTM D-2856.

  The melamine resin cured foam may include bubbles 110 having an average particle diameter of about 50 μm to about 500 μm in order to satisfy all of the structural strength and open cell ratio. When the average particle diameter of the bubbles is less than about 50 μm, the number of bubbles contained in the melamine resin cured foam may increase, and the density of the foam may increase. Release can occur. Moreover, when the average particle diameter of the bubbles exceeds about 500 μm, there is a problem that the structural strength capable of supporting the bubbles can be weakened.

  Therefore, if the average particle diameter of the bubbles is maintained within the above range, it is advantageous in terms of process conditions and physical properties. Therefore, it is possible to optimize a vacuum process without outgassing and maintain structural strength. it can.

The compressive strength of the melamine resin cured foam may be about 1.2 kgf / cm ² to about 5.0 kgf / cm ² . Compressive strength refers to the maximum compressive stress that the material can withstand without breaking, but the compressive strength is when compressing 10% of the vacuum insulation material perpendicularly or horizontally to the foaming direction of the melamine resin cured foam. And may be measured according to ASTM D-1621, JIS A-9514, KS M-3809.

When the compression strength of the melamine resin cured foam is less than about 1.2 kgf / cm ² , there is a problem that the core material formed of the foam cannot withstand the vacuum process, and the compression strength is about 5. If it exceeds 0 kgf / cm ² , the amount of foaming agent or composition used to form the melamine resin cured foam increases during the foaming process, and the number of contained bubbles increases, which may increase the density. As a result, the vacuum process time becomes long, and gas emission may occur. Therefore, by maintaining the compression strength of the melamine resin cured foam within the above range, a structural strength that can withstand a vacuum process step can be realized.

  The melamine resin cured foam may include a three-dimensional network skeleton structure. A three-dimensional network structure is a planar network structure in which specific polygons are continuous, or a structure that forms a three-dimensional structure by sharing the vertices, corners, faces, etc. of a specific polyhedron. For example, the three-dimensional network skeleton structure may include a skeleton structure in which a pentagon and a hexagon share a plane, such as a fullerene carbon structure.

  FIG. 2 is a schematic view showing the structure of the vacuum heat insulating material core according to one embodiment of the present invention, and can show that the melamine resin cured foam is formed with a three-dimensional reticulated skeleton structure. Specifically, the skeleton structure of the melamine resin cured foam may not have a cell wall.

  When the skeleton structure includes a bubble wall, not only heat is transferred through convection inside the melamine resin cured foam, but also a path through which heat is conducted through the bubble wall is shortened, and the thermal conductivity is increased. As a result, the heat insulation performance may be reduced. Moreover, the vacuum process time becomes long, and the productivity can be lowered.

For example, the melamine resin cured foam may be a melamine-formaldehyde foam, which can be produced by extruding a solution containing a melamine-formaldehyde precondensate and a blowing agent through an extruder. Specifically, the melamine-formaldehyde foam having a skeletal structure without a bubble wall can be manufactured by heating and expanding immediately after the solution is discharged through a die. As the foaming agent, hydrocarbons, halogenated fluorinated hydrocarbons, and CO ₂ may be used as physical foaming agents.

(Vacuum insulation)
In another embodiment of the present invention, there is provided a vacuum heat insulating material including a core material for a vacuum heat insulating material formed of a melamine resin cured foam having an open cell ratio of 80% or more and a jacket material for vacuum-packaging the core material. provide.

  Further, the vacuum heat insulating material is formed including a core material made of the melamine resin cured foam as described above and a jacket material for vacuum packaging the core material, and a getter material attached to or inserted into the core material. Further, it may be formed. The getter material may generate gas and moisture inside the jacket material due to an external temperature change, but may be included to prevent this.

  The getter material may be formed of quick lime (CaO) and a pouch containing the same. At this time, quick lime powder having a purity of 95% or more is used, and the pouch is also formed of crepe paper and polypropylene (PP) impregnated nonwoven fabric so that a moisture absorption performance of 25% or more can be secured. At this time, the thickness of the getter material is preferably within about 2 mm in consideration of the thickness of the entire vacuum heat insulating material.

  FIGS. 3A and 3B are sectional views showing a vacuum heat insulating material according to an embodiment of the present invention. FIG. 3A is a view showing a vacuum heat insulating material sealed with the jacket material 200 in a state where the getter material 300 is attached to the surface of the core material 100, and FIG. It is the figure which showed the vacuum heat insulating material which sealed the jacket material 200 in the state which inserted the getter material 300 in the inside of the material 100. FIG.

  The jacket material is a sealing body that surrounds the vacuum heat insulating material core, and the specific shape and manufacturing method thereof will be described below. FIG. 4 is a cross-sectional view of a jacket material included in the vacuum heat insulating material according to the embodiment.

  Referring to FIG. 4, in the jacket material 200, a metal barrier layer 220 and a surface protective layer 210 are sequentially formed on the adhesive layer 230. The adhesive layer 230 is a layer formed inside the sealing body, and the surface protective layer 210 can be defined as a layer exposed to the outermost surface.

  The adhesive layer 230 is a layer that is heat-sealed to each other by heat sealing, and performs a function of maintaining a vacuum state. Therefore, the adhesive layer 230 is made of high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), unstretched polypropylene (CPP), stretched polypropylene (OPP), polychlorinated, which can be easily heat-sealed. Heat containing at least one selected from the group consisting of vinylidene (PVDC), polyvinyl chloride (PVC), ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol copolymer (EVOH), and combinations thereof. Preferably, it is formed from a plastic film and is formed to a thickness of about 1 μm to about 100 μm to provide sufficient sealing properties.

  Next, a metal thin film having a thickness of about 6 μm to about 7 μm is formed on the adhesive layer 230 as a barrier layer 220 for gas blocking and core material protection. At this time, the aluminum foil metal barrier layer 220 is generally used most often, and since a thin film having characteristics superior to that of the aluminum foil has not been clarified, the aluminum foil is also used in one embodiment of the present invention. At this time, since aluminum is a metal material, there may be a problem that a crack is generated at the time of bending, but in order to prevent this, the surface protective layer 210 is formed on the upper portion of the metal barrier layer 220.

  The surface protective layer 210 of the outer cover material is a polyethylene terephthalate (PET) film or a polyvinylidene chloride (PVDC) / polyethylene terephthalate (PET) film having a thickness of about 10 μm to about 14 μm, and a thickness of about 20 μm to about 30 μm. It may be formed of a laminated structure of nylon film. In this case, if the degree of cracks generated in the metal barrier layer 220 is serious, the polyethylene terephthalate / nylon film may be damaged. In order to prevent this, a vinyl resin is formed on the polyethylene terephthalate layer. A layer may be coated and used.

  The vinyl resin layer is selected from the group consisting of polyvinyl chloride (PVC), polyvinyl acetate (PVA), polyvinyl alcohol (PVAL), polyvinyl butyral (PVB), polyvinylidene chloride (PVDC), and combinations thereof. One or more vinyl resins may be used. In addition, the surface protective layer 210, the metal barrier layer 220, and the adhesive layer 230 may be bonded using a polyurethane (PU) resin, respectively, in order to further improve the airtight characteristics of the jacket material. By forming the jacket material 200 in this way, the vacuum heat insulating material can have the highest airtightness and long-term durability performance.

(Method for manufacturing vacuum insulation)
In still another embodiment of the present invention, a step of manufacturing a vacuum heat insulating material core formed of a melamine resin cured foam having an open cell ratio of 80% or more; 50 ° C to 250 ° C with respect to the core material A step of applying a pressure of 0.5 Pa to 10 Pa at a temperature of 10 minutes to 200 minutes to remove residual substances; and a step of vacuum packaging after surrounding the core material with an outer cover material; A manufacturing method is provided.

  The core material composed of the cured melamine resin foam is formed by mixing melamine-formaldehyde resin, curing agent, foaming agent and other additives at high speed and curing at a temperature higher than room temperature, but the reaction product As a result, not only water is generated but also residual monomers are left, so that the probability of outgassing after the vacuum packaging step or fabrication is very high.

  Therefore, before the vacuum packaging step, a pressure of about 0.5 Pa to about 100 Pa is applied to the core at a temperature of about 50 ° C. to about 250 ° C. for about 10 minutes to about 200 minutes, and residual monomers (formaldehyde, residual phenol, water) Alternatively, compounds capable of causing gas emission such as VOC (volatile organic compound) can be removed. Moreover, since the manufacturing method of the said vacuum heat insulating material can minimize the gas and water | moisture content which generate | occur | produce in a core material, the above getter materials can also be abbreviate | omitted. In addition, the melamine resin cured foam has an open cell ratio of about 80% or more, and maintains a high porosity (about 50% or more) even after production, and thus exhibits excellent performance. Can do.

  In the following, specific examples of the present invention are presented. However, each example described below is only for specifically illustrating or explaining the present invention, and the present invention is not limited thereby.

<Examples and Comparative Examples>
Example 1
A melamine resin cured foam having an average particle diameter of 100 μm, an open cell ratio of 95%, and a compressive strength of 1.5 kgf / cm ² is a size of 8 mm × 190 mm × 250 mm (thickness × width × length). Then, it was used as a core material for a vacuum heat insulating material. Next, a jacket material formed of a structure of polyvinylidene chloride (PVDC) / polyethylene terephthalate film (PET) 12 μm, nylon film 25 μm, aluminum foil 7 μm, and linear low density polyethylene (LLDPE) film 50 μm was formed. Next, two getter materials manufactured by putting 25 g of quick lime (CaO) with a purity of 95% in a pouch were inserted into the surface of the core material. Then, all the residual gas of 5 Pa was discharged | emitted at the temperature of 150 degreeC, and after inserting the said core material in the sealing body, the vacuum heat insulating material which concerns on this invention was manufactured by sealing in the vacuum degree state of 10 Pa.

(Example 2)
A melamine resin cured foam having an average particle diameter of 100 μm, an open cell ratio of 90%, and a compressive strength of 1.2 kgf / cm ² is a size of 8 mm × 190 mm × 250 mm (thickness × width × length). Then, a vacuum heat insulating material was manufactured under the same conditions as in Example 1 except that it was used as a core material for a vacuum heat insulating material.

(Comparative Example 1)
Except that only the glass fiber board was manufactured to a size of 8 mm × 190 mm × 250 mm (thickness × width × length) and then used as a core material for a vacuum heat insulating material, the same conditions as in Example 1 were used. A vacuum insulation was produced.

(Comparative Example 2)
Polyurethane foam with an average cell diameter of 150 μm, an open cell ratio of 95%, and a compressive strength of 1.5 kgf / cm ² is manufactured to a size of 8 mm × 190 mm × 250 mm (thickness × width × length) After that, a vacuum heat insulating material was manufactured under the same conditions as in Example 1 except that it was used as a core material for a vacuum heat insulating material.

(Comparative Example 3)
A melamine resin cured foam having an average cell diameter of 100 μm, an open cell ratio of 70%, and a compressive strength of 1.5 kgf / cm ² is a size of 8 mm × 190 mm × 250 mm (thickness × width × length). Then, a vacuum heat insulating material was manufactured under the same conditions as in Example 1 except that it was used as a core material for a vacuum heat insulating material.

<Experimental example> Measurement of thermal conductivity of vacuum heat insulating material The vacuum heat insulating materials of the above-mentioned examples and comparative examples were put in a constant temperature chamber at 85 ° C and maintained for 3 months, and the heat was not transferred to the heat insulating material. It carried out while comparing the rates. At this time, an HC-074-200 (manufactured by EKO) thermal conductivity measuring machine was used for measuring the thermal conductivity. Next, the thermal conductivity from the initial stage to 10 years was predicted by applying an acceleration factor, and the result was converted into an adiabatic value (W / mK) and shown in Table 2 below.

  In the case of Examples 1 and 2, the initial heat insulation values are Comparative Example 1 using glass fiber board as the core material for vacuum heat insulating material, Comparative Example 2 using polyurethane foam as the core material for vacuum heat insulating material, and melamine resin curing Although the foam was used as the core material for the vacuum heat insulating material, it was found that it was measured lower than the comparative example 3 in which the open cell ratio was less than 80%. In addition, it can be confirmed that the increase in thermal conductivity with time was also shown to be significantly lower than in each comparative example.

Therefore, it was found that the vacuum heat insulating material using the melamine resin cured foam as the core material for the vacuum heat insulating material is excellent in the initial heat insulating performance and the long-term durability performance. Moreover, although the vacuum heat insulating material was manufactured using the melamine resin hardening foam as a core material for vacuum heat insulating materials through the comparative example 3, in this case, the open cell rate of the said core material for vacuum heat insulating materials shall be 80% or more. It could not be ensured and the compressive strength could be improved.

Claims (11)

A core material for a vacuum heat insulating material formed of a melamine resin cured foam having an open cell ratio of 80% or more. The said melamine resin cured foam is a core material for vacuum heat insulating materials of Claim 1 containing the bubble whose average particle diameter is 50 micrometers-500 micrometers. The core material for a vacuum heat insulating material according to claim 1, wherein the melamine resin cured foam has a compressive strength of 1.2 kgf / cm ^{2 to} 5.0 kgf / cm ² . The core material for a vacuum heat insulating material according to claim 1, wherein the melamine resin cured foam includes a three-dimensional network skeleton structure. The core material for a vacuum heat insulating material according to claim 4, wherein the skeleton structure does not include a bubble wall. A vacuum heat insulating material comprising: a core material formed of the melamine resin cured foam according to any one of claims 1 to 5; and a jacket material for vacuum-packaging the core material. The vacuum heat insulating material according to claim 6, wherein the vacuum heat insulating material further includes a getter material attached to or inserted into the core material and having a moisture absorption rate of 25% or more. The vacuum jacket according to claim 6, wherein the jacket material includes a laminated structure of a surface protective layer, a metal barrier layer, and an adhesive layer from the outside. The surface protective layer has a layer structure of polyethylene terephthalate (PET) and nylon film,
The metal barrier layer is formed of aluminum foil,
The adhesive layer is made of high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), unstretched polypropylene (CPP), stretched polypropylene (OPP), polyvinylidene chloride (PVDC), polyvinyl chloride. The vacuum heat insulation according to claim 8, which is at least one selected from the group consisting of (PVC), ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol copolymer (EVOH), and combinations thereof. Wood. The vacuum heat insulating material according to claim 8, wherein the adhesion between the surface protective layer and the metal barrier layer and the adhesion between the metal barrier layer and the adhesive layer are each made of polyurethane (PU) resin. The step of manufacturing the core material of the melamine resin cured foam according to any one of claims 1 to 5;
Applying a pressure of 0.5 Pa to 10 Pa to the core material at a temperature of 50 ° C. to 250 ° C. for 10 minutes to 200 minutes to remove residual substances; and after surrounding the core material with a jacket material A method for producing a vacuum heat insulating material.

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