JP2022038360A - Heat insulation member and manufacturing method thereof - Google Patents

Abstract

To provide a heat insulation member with high heat insulation properties, having flame resistance, and excellent in interlayer adhesive properties.SOLUTION: A heat insulation member 10 includes: a first heat insulation layer 11; a second heat insulation layer 12 laminated on the first heat insulation layer 11; a heat reflection layer 14 laminated on the second heat insulation layer 12; and a flame retardant adhesion layer 13 interposing the second heat insulation layer 12 and the heat reflection layer 14 and having an adhesive component and a flame retarder. The second heat insulation layer 12 includes: a porous structure body having a plurality of particles bound to form a skeleton, with pores inside thereof and a hydrophobic portion on a surface and, in the inside thereof, at least on a surface; and a second aqueous binder whose solvent is water. The first heat insulation layer 11 and the second heat insulation layer 12 are adhered by the second aqueous binder included in the second heat insulation layer 12. The second heat insulation layer 12 and the heat reflection layer 14 are adhered by the flame retardant adhesion layer 13.SELECTED DRAWING: Figure 1

Description

The present invention relates to a heat insulating material using a porous structure having a low thermal conductivity and a method for producing the same.

Various heat insulating members have been conventionally used for the purpose of heat flow control in in-vehicle parts, building materials for houses, industrial equipment and the like. For example, in an electric vehicle such as a hybrid vehicle or an electric vehicle, it is required to improve the power consumption rate (electricity cost) and extend the mileage. At present, about 50% of the battery energy of electric vehicles is lost in air conditioning, so in order to improve electricity costs, in addition to reducing the weight of interior parts, improve heat insulation to reduce heat loss in air conditioning. Is required. Further, in electrical equipment and electronic equipment, a thin and highly heat insulating member is required so that it can be arranged in a limited narrow space in a housing. Further, depending on the application, flame retardancy may be required in addition to heat insulation.

As the heat insulating member, those using silica airgel are known (see, for example, Patent Documents 1 to 5). Silica airgel is a porous material in which silica fine particles are linked to form a skeleton and have a pore structure having a size of about 10 to 50 nm. Silica airgel is a useful material for improving the heat insulating property of a member because of its low thermal conductivity.

Japanese Unexamined Patent Publication No. 2017-155402 Special Table 2014-502305 Gazette Japanese Unexamined Patent Publication No. 8-174740 International Publication No. 2017/038769 Japanese Unexamined Patent Publication No. 2018-118488

Patent Document 1 describes a flexible insulating structure in which a non-woven fabric (batting) is impregnated with a mixture of airgel-containing particles and a binder. However, the layer containing airgel alone does not have sufficient heat insulating properties, and there is also a problem that the airgel-containing particles supported on the non-woven fabric are easily dropped off. Further, when the mixture (slurry) containing airgel is impregnated in the entire thickness direction of the nonwoven fabric as in the form described in claim 3 of Patent Document 1, the voids in the nonwoven fabric disappear. As a result, the heat transfer method is mainly heat conduction, and the effect of improving the heat insulating property is reduced. Paragraph [0060] of Patent Document 1 describes that a flame retardant can be added to the mixture. However, since the mixing ratio of airgel is lowered by the amount of the blended flame retardant, the heat insulating property is lowered.

Patent Document 2 describes a composite material containing a binder and airgel, and paragraph [0061] describes that the composite material may contain a flame retardant. However, in this case as well, as in the case of Patent Document 1, the mixing ratio of airgel is lowered by the amount of the blended flame retardant, so that the heat insulating property is lowered. Further, in paragraphs [0072] and [0073], it is described that the coating layer can be arranged on both sides of the sheet-shaped composite material, but there is no specific description about the bonding method between the composite material and the coating layer. ..

Patent Document 3 describes a transparent heat insulating panel including an airgel and an infrared blocking film. However, since the airgel layer is composed of a single airgel that does not contain a binder component, there is a problem that the airgel layer is poorly flexible, has poor adhesion to an infrared blocking film, and is easily dropped off. In this regard, paragraph [0027] describes that an adhesive layer is laminated on an infrared blocking film, and airgel is layered on the adhesive layer and pressed to integrate them, but there is no description regarding the components of the adhesive layer.

Patent Document 4 describes an airgel laminate including a base material, a resin layer having a nitrogen atom, and an airgel layer. The base material and the airgel layer are adhered by a resin layer, but the airgel layer is composed of a single airgel that does not contain a binder component, and therefore has poor flexibility. Further, since the airgel layer is manufactured by applying a sol coating solution on the resin layer formed on the base material and then drying, aging, washing, solvent replacement, and drying, the manufacturing process is complicated. be.

Patent Document 5 describes an airgel laminated composite in which a spacer layer such as a non-woven fabric, an airgel layer, and a support having a heat ray reflecting function or a heat ray absorbing function are laminated. In this case as well, as in the case of Patent Document 4, the airgel layer is composed of a single airgel containing no binder component. Therefore, the airgel layer has poor flexibility. In addition, the airgel layer and the spacer layer must be sewn or bonded (paragraph [0159]). Further, since the airgel layer is manufactured through the steps of drying, aging, washing, solvent replacement, and drying after applying the sol coating solution on the support, the manufacturing process is complicated.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a heat insulating member having high heat insulating properties, flame retardancy, and excellent interlayer adhesiveness. Another object of the present invention is to provide a method for manufacturing the heat insulating member at a relatively low cost.

(1) In order to solve the above problems, the heat insulating member of the present invention includes a first heat insulating layer, a second heat insulating layer laminated on the first heat insulating layer, and a heat reflecting layer laminated on the second heat insulating layer. A flame-retardant adhesive layer having an adhesive component and a flame retardant, which is interposed between the second heat insulating layer and the heat reflecting layer, is provided, and the second heat insulating layer has a plurality of particles connected to each other. The first heat insulating layer has a porous structure having a skeleton, internal pores, and a hydrophobic portion on the surface and at least the surface thereof, and a second aqueous binder using water as a solvent. And the second heat insulating layer are adhered by the second aqueous binder contained in the second heat insulating layer, and the second heat insulating layer and the heat reflecting layer are bonded by the flame retardant adhesive layer. It is characterized by.

(2) The first manufacturing method of the present invention, which is one of the preferred manufacturing methods for the heat insulating member of the present invention, is a heat insulating paint having the porous structure and the second water-based binder in the first heat insulating layer. The first step is to apply a heat insulating paint to form a coating film, and to apply an adhesive coating having the adhesive component and the flame retardant to the heat reflective layer to form a coating film. A curing step of superimposing the heat insulating layer and the heat reflecting layer so that the formed coating films are in contact with each other and curing the two coating films to form the second heat insulating layer and the flame retardant adhesive layer. And, characterized by having.

(3) In the second manufacturing method of the present invention, which is one of the preferred manufacturing methods for the heat insulating member of the present invention, the heat insulating paint having the porous structure and the second water-based binder in the first heat insulating layer. And the heat insulating paint coating step of forming the coating film of the heat insulating paint, and the adhesive paint having the adhesive component and the flame retardant is applied to the surface of the coating film of the heat insulating paint to apply the adhesive paint. The adhesive paint application step of forming a film and the heat-reflecting layer are superposed on the coating film of the adhesive paint in the first heat insulating layer, and the two coating films of the heat insulating paint and the adhesive paint are cured. It is characterized by having a second heat insulating layer and a curing step for forming the flame retardant adhesive layer.

(1) The heat insulating member of the present invention includes two heat insulating layers, a first heat insulating layer and a second heat insulating layer. Of these, the second heat insulating layer has a porous structure. The size of the pores formed between the skeletons of the porous structure is about 10 to 50 nm, and most of the pores are so-called mesopores of 50 nm or less. Since the mesopores are smaller than the mean free path of air, heat transfer due to convection is hindered. Due to the high heat insulating effect of the porous structure, the second heat insulating layer has high heat insulating properties.

Further, the second heat insulating layer has a second aqueous binder. The second aqueous binder is a binder that uses water as a solvent and is relatively flexible. For this reason, the second heat insulating layer is flexible, and it is easier to arrange it on a curved surface or the like as compared with a layer made of a single porous structure, but also cracks and shedding of the porous structure (so-called powder falling). There are few. The second aqueous binder has adhesiveness and not only bonds the porous structures contained in the second heat insulating layer to each other, but also plays a role of adhering the adjacent layers. That is, the second water-based binder adheres the second heat insulating layer and the first heat insulating layer adjacent thereto. As described above, according to the heat insulating member of the present invention, the first heat insulating layer and the second heat insulating layer can be adhered by the action of the second water-based binder. There is no need to use a fixing member. Therefore, according to the heat insulating member of the present invention, it is possible to reduce the thickness, reduce the manufacturing man-hours, and reduce the cost.

The heat insulating member of the present invention includes a heat reflecting layer in addition to the two heat insulating layers. The heat-reflecting layer mainly plays a role of reflecting heat. There are three forms of heat transfer phenomena: conduction, convection, and radiation. The effect of improving the heat insulating property by the two heat insulating layers is mainly due to the suppression of "conduction and convection". When a heat reflecting layer is added to the two heat insulating layers, the effect of "radiation" can be utilized in addition to the suppression of "conduction and convection", and the heat insulating property of the heat insulating member as a whole is further improved. For example, when the heat source is on the heat reflecting layer side, the heat radiated from the heat source is reflected by the heat reflecting layer, so that the heat transfer to the heat insulating member can be suppressed. Conversely, if the heat source is on the opposite side of the heat-reflecting layer, the heat radiated from the heat source passes through the first and second heat-insulating layers and reaches the heat-reflecting layer mainly by conduction and convection. .. Even in this case, the heat that has reached the heat-reflecting layer is reflected by the heat-reflecting layer toward the second heat insulating layer. As a result, most of the heat radiated from the heat source can be blocked by the heat insulating member.

The heat-reflecting layer is adhered to the second heat insulating layer by the flame-retardant adhesive layer. As described above, it is possible to bond the second heat insulating layer and the heat reflecting layer by the action of the second water-based binder contained in the second heat insulating layer, but a flame-retardant adhesive layer is added between the two layers. Thereby, the adhesive force between the layers can be further enhanced. For example, by increasing the blending amount of the second aqueous binder in the second heat insulating layer, the adhesive force between the layers can be enhanced. However, in this method, it is difficult to maintain the desired heat insulating property because the blending ratio of the porous structure decreases by the amount of the second aqueous binder. In this respect, in the heat insulating member of the present invention, the adhesive strength is improved by interposing a flame-retardant adhesive layer between the second heat insulating layer and the heat reflecting layer. Thereby, the adhesive strength can be enhanced without increasing the blending amount of the second aqueous binder, in other words, without reducing the blending amount of the porous structure, while maintaining the heat insulating property. Since the heat insulating member of the present invention is hard to peel off from each other and has high durability, it can be applied to various applications and is highly practical.

The flame-retardant adhesive layer has an adhesive component and a flame retardant. That is, in the heat insulating member of the present invention, the flame retardant is blended not in the second heat insulating layer but in the flame retardant adhesive layer. Therefore, flame retardancy can be imparted while maintaining the heat insulating property without reducing the blending amount of the porous structure.

As described above, the heat insulating member of the present invention has high heat insulating properties, flame retardancy, and excellent interlayer adhesiveness even if it is relatively thin. For example, when the heat insulating member of the present invention is applied to an interior part of an automobile, heat transfer from inside and outside the vehicle can be suppressed, and heat energy consumption in the interior part can be suppressed. As a result, the heat loss of the air conditioner is reduced, and the electricity cost can be improved. When the heat insulating member of the present invention is applied to a wall material for a house, an attic, a window sash, etc., it is effective in improving the heat insulating property in the room. Further, since the heat insulating member of the present invention is relatively thin and flexible, it can be easily applied to a narrow space such as an electric device or an electronic device.

(2) In the first method for manufacturing a heat insulating member of the present invention, first, a heat insulating paint is applied to the first heat insulating layer to form a coating film, and then an adhesive paint is applied to the heat reflecting layer to form a coating film. I'll keep it. Then, before the two formed coating films are cured, the first heat insulating layer and the heat reflecting layer are overlapped so that the respective coating films are in contact with each other, and the two coating films are cured. .. When the coating film of the heat insulating paint is cured, it becomes a second heat insulating layer, and the first heat insulating layer and the second heat insulating layer are adhered by a second water-based binder contained in the second heat insulating layer. When the coating film of the adhesive paint is cured, it becomes a flame-retardant adhesive layer, and the second heat insulating layer and the heat-reflecting layer are adhered by the flame-retardant adhesive layer. As described above, according to the first manufacturing method of the present invention, a coating film of a heat insulating paint and a coating film of an adhesive paint are formed, and these are cured together to form a second heat insulating layer and bond the layers to each other. Since the above can be performed at the same time, the heat insulating member of the present invention can be easily manufactured at a relatively low cost. Further, since the coating film of the adhesive paint is formed separately without being superimposed on the coating film of the heat insulating paint in a wet state, there are few restrictions on the method of applying the adhesive paint as compared with the case where the coating film is formed in layers.

(3) In the second manufacturing method of the heat insulating member of the present invention, first, the heat insulating paint is applied to the first heat insulating layer to form a coating film of the heat insulating paint, and then the coating film of the heat insulating paint is adhered to the surface. The paint is applied in layers to form a coating film of adhesive paint. Then, before the two coating films formed on top of each other are cured, the heat-reflecting layer is superposed on the coating film of the adhesive paint on the surface layer to cure the two coating films. In the case of the second manufacturing method, as in the first manufacturing method, when the coating film of the heat insulating paint is cured, it becomes a second heat insulating layer, and the first heat insulating layer and the second heat insulating layer are contained in the second heat insulating layer. It is adhered by a second aqueous binder to be bonded. When the coating film of the adhesive paint is cured, it becomes a flame-retardant adhesive layer, and the second heat insulating layer and the heat-reflecting layer are adhered by the flame-retardant adhesive layer. As described above, according to the second manufacturing method of the present invention, a coating film of a heat insulating paint and a coating film of an adhesive paint are formed, and these are cured together to form a second heat insulating layer and bond the layers to each other. Since the above can be performed at the same time, the heat insulating member of the present invention can be easily manufactured at a relatively low cost.

It is a cross-sectional view in the thickness direction of the heat insulating member of 1st Embodiment. It is a schematic diagram which shows the heat transfer phenomenon in the summer in the form which used the heat insulating member for the door trim of an automobile. It is a schematic diagram which shows the heat transfer phenomenon in winter in the form which used the heat insulating member for the door trim of an automobile. It is a cross-sectional view in the thickness direction of the heat insulating member of the 2nd Embodiment. It is a cross-sectional view in the thickness direction of the heat insulating member of the third embodiment. It is a graph which shows the measurement result of the reflectance of the aluminum vapor deposition film which is a heat reflection layer. It is a cross-sectional view in the thickness direction of the sample of Example 1. FIG. It is a schematic diagram of the experimental device used for the evaluation of the heat insulating property. It is a graph which shows the time-dependent change of the temperature measured in the evaluation experiment of adiabatic property.

Hereinafter, embodiments of the heat insulating member of the present invention and the method for manufacturing the same will be described.

<First Embodiment>
[Constitution]
First, the configuration of the heat insulating member of the present embodiment will be described. FIG. 1 shows a cross-sectional view in the thickness direction of the heat insulating member of the present embodiment. In FIGS. 1 to 4 below, the thickness direction (stacking direction) of the members is defined as the inner / outer direction. As shown in FIG. 1, the heat insulating member 10 includes a first heat insulating layer 11, a second heat insulating layer 12, a flame-retardant adhesive layer 13, and a heat reflecting layer 14 in this order from the inside.

The first heat insulating layer 11 is made of a non-woven fabric. The thickness of the first heat insulating layer 11 is 1.0 mm. The second heat insulating layer 12 is arranged outside the first heat insulating layer 11. The second heat insulating layer 12 has a porous structure, a urethane resin as a second aqueous binder, and carboxylmethyl cellulose (CMC) as a polysaccharide. The porous structure is a silica airgel in which a plurality of silica particles are connected to form a skeleton and have pores inside. Silica airgel has hydrophobic sites on the surface and inside. The thickness of the second heat insulating layer 12 is 0.5 mm. The content of the urethane resin (second water-based binder) in the second heat insulating layer 12 is 4.2% by volume when the whole of the second heat insulating layer 12 is 100% by volume. The first heat insulating layer 11 and the second heat insulating layer 12 are adhered to each other by the urethane resin contained in the second heat insulating layer 12. A part of the second heat insulating layer 12 is impregnated in the vicinity of the outer surface of the first heat insulating layer 11. The impregnation depth of the second heat insulating layer 12 in the first heat insulating layer 11 is 0.1 mm.

The flame-retardant adhesive layer 13 is arranged outside the second heat insulating layer 12. The flame-retardant adhesive layer 13 has a urethane resin as a first aqueous binder, which is an adhesive component, and ammonium polyphosphate as a flame retardant. The first water-based binder contained in the flame-retardant adhesive layer 13 and the second water-based binder contained in the second heat insulating layer 12 are the same. The thickness of the flame-retardant adhesive layer 13 is 0.03 mm. The content of the flame retardant in the flame-retardant adhesive layer 13 is 80% by mass when the entire flame-retardant adhesive layer 13 is 100% by mass.

The heat-reflecting layer 14 is arranged outside the second heat insulating layer 12 via the flame-retardant adhesive layer 13. The heat-reflecting layer 14 is made of an aluminum-deposited film. The aluminum-deposited film is formed by depositing aluminum on the surface of a polyethylene terephthalate (PET) film. That is, the heat reflecting layer 14 has a resin layer made of PET film and a metal layer made of aluminum. The thickness of the heat reflecting layer 14 is 0.025 mm. The reflectance of the heat reflecting layer 14 is 80% or more in the region where the wavelength of the incident light is 780 nm or more and 2500 nm or less. The heat reflecting layer 14 and the second heat insulating layer 12 are bonded by a flame-retardant adhesive layer 13. The PET film side of the heat reflecting layer 14 is adhered to the second heat insulating layer 12.

[Production method]
Next, a method of manufacturing the heat insulating member of the present embodiment will be described. In the present embodiment, the heat insulating member 10 is manufactured by the first manufacturing method of the present invention. First, a heat insulating paint having water, a urethane resin emulsion as a second aqueous binder, silica airgel, and CMC is prepared. In addition, an adhesive paint having water, a urethane resin emulsion as a first aqueous binder, and ammonium polyphosphate powder is prepared. Next, the prepared heat insulating paint is applied to one surface of the nonwoven fabric as the first heat insulating layer 11 to form a coating film (heat insulating paint application step). Further, the prepared adhesive paint is applied to the surface of the aluminum-deposited film as the heat reflective layer 14 on the PET film side to form a coating film (adhesive paint application step). Then, the non-woven fabric and the aluminum-deposited film are overlapped with each other so as to be in contact with each other while being pressurized. Then, the obtained laminate is dried at 150 ° C. for 5 minutes to cure the coating film of the heat insulating paint to form the second heat insulating layer 12, and the coating film of the adhesive paint is cured to form the flame-retardant adhesive layer 13 ( Curing process).

[Action effect]
Next, the operation and effect of the heat insulating member of the present embodiment and the manufacturing method thereof will be described. The second heat insulating layer 12 constituting the heat insulating member 10 of the present embodiment has a porous structure and a second water-based binder. Therefore, it is flexible and has excellent heat insulating properties. Then, the first heat insulating layer 11 and the second heat insulating layer 12 are adhered by the action of the second aqueous binder. Therefore, it is not necessary to use an adhesive or a fixing member to fix these two layers. Therefore, according to the heat insulating member 10, the thickness can be reduced, the manufacturing man-hours can be reduced, and the cost can be reduced. Further, the second heat insulating layer 12 is impregnated only in the vicinity of the outer surface of the first heat insulating layer 11, that is, only the surface layer portion in contact with the second heat insulating layer 12. Therefore, most of the voids in the first heat insulating layer 11 remain without being filled with the material of the second heat insulating layer 12, and heat transfer by convection is maintained.

The second heat insulating layer 12 has a polysaccharide. As will be described in detail later, when a polysaccharide is added to the heat insulating paint, the viscosity of the heat insulating paint becomes high and the polysaccharide creates a state like a protective colloid, which makes it difficult to separate the porous structure from the binder liquid. .. As a result, the dispersibility of the porous structure is improved, and the porous structure can be stably held in the heat insulating paint. Further, when the viscosity of the heat insulating paint becomes high, dripping is less likely to occur, so that the coating on the first heat insulating layer 11 becomes easy.

The heat insulating member 10 includes a heat reflecting layer 14 in addition to the two heat insulating layers 11 and 12. As a result, the effect of "radiation" can be utilized in addition to "conduction and convection", so that the heat insulating property of the heat insulating member 10 as a whole is improved. Here, as an example, the heat insulating effect will be described by citing a form in which the heat insulating member 10 is used for a door trim (interior part) of an automobile. FIG. 2A schematically shows a heat transfer phenomenon in summer in a form in which the heat insulating member 10 is used for the door trim. FIG. 2B schematically shows the heat transfer phenomenon in winter in the same form. In FIGS. 2A and 2B, the door trim 1 includes a base material 15, a heat insulating member 10, and a skin material 16. For convenience of explanation, the base material 15 and the skin material 16 are shown by dotted lines. The base material 15 is made of polypropylene, and the skin material 16 is made of a laminated body in which a base cloth and a urethane film layer are laminated from the heat insulating member 10 side. In FIGS. 2A and 2B, the inside in FIG. 1 corresponds to the vehicle interior side, and the outside corresponds to the vehicle interior outside.

In the summer, heat transfer phenomena are shown for the purpose of keeping the temperature inside the vehicle low by blocking external heat as much as possible. As shown by the black arrow in FIG. 2A, the heat source is outside the vehicle interior (on the base material 15 side) in the summer. In this case, a part of the heat radiated from the heat source is reflected by the heat reflecting layer 14. As a result, the amount of heat transferred to the heat insulating member 10 can be reduced. The amount of heat that has passed through the heat-reflecting layer 14 without being reflected is further reduced by the thermal resistance when passing through the second heat insulating layer 12 and the first heat insulating layer 11 by convection and conduction. In this way, most of the heat radiated from the outside can be blocked by the heat insulating member 10. In winter, heat transfer phenomena are shown for the purpose of preventing the heat inside the vehicle from leaking to the outside due to heating or the like. As shown by the black arrow in FIG. 2B, the heat source is in the vehicle interior (skin material 16 side) in winter. In this case, the heat radiated from the heat source is transferred to the first heat insulating layer 11 and the second heat insulating layer 12, but the amount of heat passing through both layers becomes small due to the thermal resistance due to convection and conduction. Then, since the heat that has reached the heat reflection layer 14 is reflected by the heat reflection layer 14, the amount of heat that passes through the heat reflection layer 14 is further reduced. In this way, most of the heat in the vehicle interior can be blocked by the heat insulating member 10 and retained in the vehicle interior.

In the heat insulating member 10, the flame-retardant adhesive layer 13 is interposed between the second heat insulating layer 12 and the heat-reflecting layer 14, and the heat-reflecting layer 14 and the second heat-reflecting layer 12 are adhered to each other by the flame-retardant adhesive layer 13. .. Therefore, it is possible to increase the adhesive strength without increasing the amount of the second aqueous binder in the second heat insulating layer 12, in other words, without reducing the amount of the porous structure and maintaining the heat insulating property. Further, the flame retardant adhesive layer 13 has a flame retardant. Therefore, flame retardancy can be imparted while maintaining the heat insulating property without reducing the amount of the porous structure in the second heat insulating layer 12. As described above, the heat insulating member 10 is not only thin and has heat insulating properties and flame retardancy, but also has high durability in which the layers are not easily peeled off from each other. Therefore, it can be applied to various uses and is highly practical.

According to the manufacturing method of the present embodiment, a coating film of a heat insulating paint and a coating film of an adhesive paint are formed, and these are cured together to form a second heat insulating layer 12 and bond the layers at the same time. Therefore, the heat insulating member 10 can be easily manufactured at a relatively low cost. Further, since the coating film of the adhesive paint is formed separately without being superimposed on the coating film of the heat insulating paint in a wet state, there are few restrictions on the method of applying the adhesive paint as compared with the case where the coating film is formed in layers.

<Second embodiment>
The difference between the heat insulating member of the present embodiment and the heat insulating member of the first embodiment is that an adhesive sheet is added to the inside of the first heat insulating layer, and the heat insulating member is manufactured by the second manufacturing method. Here, the differences will be mainly described. FIG. 3 shows a cross-sectional view in the thickness direction of the heat insulating member of the present embodiment. In FIG. 3, the members corresponding to those in FIG. 1 are indicated by the same reference numerals.

As shown in FIG. 3, the heat insulating member 20 includes an adhesive sheet 21, a first heat insulating layer 11, a second heat insulating layer 12, a flame-retardant adhesive layer 13, and a heat reflecting layer 14 in this order from the inside. There is. The adhesive sheet 21 is arranged inside the first heat insulating layer 11. The adhesive sheet 21 has an adhesive layer 210 and a release paper 211. The adhesive layer 210 is made of an acrylic adhesive and is arranged on the first heat insulating layer 11 side. The thickness of the adhesive layer 210 is 0.075 mm. The release paper 211 covers the inner surface of the adhesive layer 210. The release paper 211 has a release agent coated on the surface of the paper and can be peeled off from the adhesive layer 210. The thickness of the release paper 211 is 0.05 mm.

The manufacturing method of the heat insulating member 20 is as follows. First, the heat insulating paint and the adhesive paint are prepared in the same manner as in the first embodiment. Next, the prepared heat insulating paint is applied to one surface of the nonwoven fabric as the first heat insulating layer 11 to form a coating film (heat insulating paint application step). Subsequently, the prepared adhesive paint is applied to the surface of the formed coating film of the heat insulating paint to form a coating film of the adhesive paint (adhesive paint application step). Then, the PET film side of the aluminum-deposited film as the heat-reflecting layer 14 is superposed on the formed coating film of the adhesive paint while applying pressure. Then, the obtained laminate is dried at 150 ° C. for 5 minutes to cure the coating film of the heat insulating paint to form the second heat insulating layer 12, and the coating film of the adhesive paint is cured to form the flame-retardant adhesive layer 13 ( Curing process). Finally, the adhesive sheet 21 is attached to the other surface of the nonwoven fabric as the first heat insulating layer 11 (the surface opposite to the one to which the second heat insulating layer 12 is adhered).

The heat insulating member 20 of the present embodiment has the same function and effect as the heat insulating member 10 of the first embodiment with respect to a portion having a common configuration. Further, according to the heat insulating member 20, the heat insulating member 20 can be easily fixed to the mating member only by peeling off the release paper 211 and adhering the adhesive layer 210 to the mating member. According to the manufacturing method of the present embodiment, a coating film of a heat insulating paint and a coating film of an adhesive paint are formed, and these are cured together to form a second heat insulating layer 12 and bond the layers at the same time. Therefore, the heat insulating member 20 can be easily manufactured at a relatively low cost.

<Third embodiment>
The difference between the heat insulating member of the present embodiment and the heat insulating member of the first embodiment is that the second heat insulating layer is arranged on both the inner and outer sides of the first heat insulating layer. Here, the differences will be mainly described. FIG. 4 shows a cross-sectional view in the thickness direction of the heat insulating member of the present embodiment. In FIG. 4, the members corresponding to those in FIG. 1 are indicated by the same reference numerals.

As shown in FIG. 4, the heat insulating member 30 includes a second heat insulating layer 31, a first heat insulating layer 11, a second heat insulating layer 12, a flame-retardant adhesive layer 13, and a heat reflecting layer 14 in this order from the inside. I have. The second heat insulating layer 31 is arranged inside the first heat insulating layer 11. The second heat insulating layer 31 has a porous structure, a urethane resin as a second aqueous binder, and CMC as a polysaccharide. The material and thickness of the second heat insulating layer 31 are the same as those of the second heat insulating layer 12. The first heat insulating layer 11 and the second heat insulating layer 31 are adhered to each other by the urethane resin contained in the second heat insulating layer 31. A part of the second heat insulating layer 31 is impregnated in the vicinity of the inner surface of the first heat insulating layer 11. The impregnation depth of the second heat insulating layer 31 in the first heat insulating layer 11 is 0.1 mm.

The manufacturing method of the heat insulating member 30 is as follows. First, in the same manner as in the first embodiment, a laminate composed of the first heat insulating layer 11, the second heat insulating layer 12, the flame-retardant adhesive layer 13, and the heat reflecting layer 14 (the heat insulating member 10 of the first embodiment) is manufactured. do. Next, the same heat insulating paint as in the first embodiment is applied to the other surface of the nonwoven fabric as the first heat insulating layer 11 (the surface opposite to the one to which the second heat insulating layer 12 is adhered), and the heat insulating paint is applied. To form a coating film. Then, the formed coating film is dried and cured at 150 ° C. for 5 minutes to form a second heat insulating layer 31, and the second heat insulating layer 31 and the first heat insulating layer 11 are adhered to each other.

The heat insulating member 30 of the present embodiment has the same function and effect as the heat insulating member 10 of the first embodiment with respect to a portion having a common configuration. Further, in the heat insulating member 30, the second heat insulating layer 31 is added to the heat insulating member 10 of the first embodiment. According to the heat insulating member 30, the thermal resistance is increased by the amount of the added second heat insulating layer 31, so that the heat insulating property of the heat insulating member 30 as a whole can be further improved.

<Other forms>
The embodiment of the heat insulating member of the present invention and the method for manufacturing the same has been described above. However, the embodiment is not limited to the above embodiment. It is also possible to carry out in various modified forms and improved forms that can be performed by those skilled in the art.

[Insulation member]
The heat insulating member of the present invention includes a first heat insulating layer, a second heat insulating layer, a heat reflecting layer, and a flame-retardant adhesive layer. First, these four layers will be described, and then other configurations will be described.

(1) First heat insulating layer The first heat insulating layer may be formed of a material having a relatively low thermal conductivity. For example, considering the application to interior parts of automobiles, wall materials for houses, electric devices, etc., the heat insulating member of the present invention may have sound absorbing property in addition to heat insulating property. From this point of view, as the first heat insulating layer, a material having voids is desirable, and examples thereof include non-woven fabrics and foams. In the case of non-woven fabric, the basis weight is preferably 150 g / m ² or less. Examples of the foam include slab urethane. The thickness of the first heat insulating layer is preferably 1 mm or more, more preferably 2 mm or more, from the viewpoint of heat insulating property and sound absorbing property.

(2) Second heat insulating layer If the second heat insulating layer is laminated on the first heat insulating layer, even if it is arranged on only one side of the first heat insulating layer as in the first and second embodiments, the third embodiment is carried out. It may be arranged on both sides of the first heat insulating layer as in the form. For example, when the second heat insulating layer is arranged on both sides in the thickness direction of the first heat insulating layer, the heat reflecting layer may be laminated on either one or both of them.

The second heat insulating layer has a porous structure and a second aqueous binder. In the porous structure, a plurality of particles are connected to form a skeleton and have pores inside. It is desirable that the diameter of the particles forming the skeleton (primary particles) is about 2 to 5 nm, and the size of the pores formed between the skeletons is about 10 to 50 nm. Most of the pores are so-called mesopores of 50 nm or less. The shape of the porous structure is not particularly limited, such as spherical or irregularly shaped lumps. When the maximum length of the porous structure is taken as the particle size, the average particle size of the porous structure is preferably about 1 to 200 μm. As the particle size of the porous structure becomes larger, the surface area becomes smaller and the pore volume becomes larger, so that the effect of enhancing the heat insulating property becomes larger. For example, those having an average particle diameter of 10 μm or more are suitable. On the other hand, considering the stability of the heat insulating paint in which the porous structure is dispersed in the binder liquid, the ease of coating, and the suppression of the porous structure from falling off in the second heat insulating layer, the average particle size is 100 μm. The following are suitable. In addition, when two or more types having different particle diameters are used in combination, the small-diameter porous structure enters the gap between the large-diameter porous structures, so that the filling amount can be increased and the effect of improving the heat insulating property is great. Become.

Porous structures include hydrophilic ones having hydrophilic parts on the surface and inside, and hydrophobic ones having hydrophobic parts. Of these, the hydrophilic porous structure is brittle and easily collapses. In addition, there is a risk that moisture or the like will infiltrate the inside and the pores will be crushed. Therefore, in the heat insulating member of the present invention, a hydrophobic member having a hydrophobic portion on at least the surface of the surface and the inside is used. When a hydrophobic porous structure is used, when a second aqueous binder using water as a solvent is used, the binder does not easily penetrate into the pores of the porous structure, so that the heat insulating property is not easily impaired. Further, the surface of the porous structure may be surface-treated with a silane coupling agent or the like. By applying the surface treatment, it is possible to impart functions such as hydrophobicity to the surface of the porous structure.

The type of the porous structure is not particularly limited. Examples of the primary particles include silica, alumina, zirconia, titania and the like. Among them, from the viewpoint of excellent chemical stability, silica aerogel in which the primary particles are silica, that is, a plurality of silica particles are connected to form a skeleton is desirable. Silica airgel is white and reflects infrared rays. Therefore, when silica airgel is used, a heat shielding effect can be imparted to the second heat insulating layer.

A silica airgel having a hydrophobic portion on at least the surface of the surface and the inside can be produced by subjecting it to a hydrophobic treatment such as imparting a hydrophobic group in the production process. When the surface has at least a hydrophobic portion, it is possible to suppress the infiltration of water and the like, so that the pore structure is maintained and the heat insulating property is not easily impaired. The method for producing silica airgel is not particularly limited, and the drying step may be performed at normal pressure or supercritical. For example, if the hydrophobizing treatment is performed before the drying step, it is not necessary to dry at supercritical, that is, it is sufficient to dry at normal pressure, so that it can be manufactured more easily and at low cost. The silica airgel may be produced, for example, by the method described in Japanese Patent No. 5250900.

The content of the porous structure in the second heat insulating layer may be appropriately determined in consideration of the heat insulating property, flexibility, mechanical strength and the like of the second heat insulating layer. For example, from the viewpoint of reducing the thermal conductivity (increasing the heat insulating property), the content of the porous structure should be 80% by volume or more when the volume of the entire second heat insulating layer is 100% by volume. Is desirable. It is more preferable that it is 85% by volume or more. On the other hand, when the number of porous structures increases, the content of the binder decreases accordingly, so that the porous structures may easily fall off or the adhesive strength between adjacent layers may decrease. Therefore, the content of the porous structure is preferably 96% by volume or less when the volume of the entire second heat insulating layer is 100% by volume.

The second aqueous binder is a binder using water as a solvent, and is not particularly limited as long as it can bond the porous structures to each other and adjacent layers. Examples of the second aqueous binder include a water-soluble binder and an emulsion-like binder, and among them, an emulsion-like binder (aqueous emulsion-based binder) is preferable. Aqueous emulsion binders are emulsified by the introduction of surfactants or hydrophilic groups. According to the aqueous emulsion-based binder, the hydrophilicity is lowered due to the volatilization of the surfactant and the hydrophilic group during drying, and it becomes difficult to dissolve in water. Therefore, it is considered that the heat insulating paint is less likely to become sticky after being cured. The emulsifying method may be a forced emulsification type using a surfactant as an emulsifier or a self-emulsifying type in which a hydrophilic group is introduced.

The binder component may be resin or rubber. The glass transition temperature (Tg) of the binder is -5 ° C or lower, and further -20 ° C or lower, from the viewpoint of having high adhesiveness to the porous structure and making the second heat insulating layer flexible to prevent cracking. desirable. For example, in the case of an aqueous emulsion-based binder, it may be a resin emulsion or a rubber emulsion. Examples of the resin include acrylic resin, urethane resin, and a mixture of acrylic resin and urethane resin. Examples of the rubber include styrene butadiene rubber (SBR), nitrile rubber, silicone rubber, urethane rubber, acrylic rubber and the like. Urethane resin, styrene-butadiene rubber, and the like are suitable from the viewpoint of making the second heat insulating layer flexible. From the viewpoint of increasing the strength of the binder portion and improving the strength of the second heat insulating layer, the binder component may be crosslinked by using a crosslinking agent or the like in combination.

The second heat insulating layer is adhered to the first heat insulating layer by a second aqueous binder. The content of the second aqueous binder may be appropriately determined in consideration of the adhesiveness, heat insulating property, etc. of the second heat insulating layer. For example, from the viewpoint of enhancing the adhesiveness, the content of the second aqueous binder is preferably 4.0% by volume or more when the volume of the entire second heat insulating layer is 100% by volume. It is more preferable that the content is 6.0% by volume or more, more preferably 9.0% by volume or more. On the other hand, from the viewpoint of reducing the thermal conductivity (increasing the heat insulating property), the content of the second aqueous binder is 20% by volume or less when the volume of the entire second heat insulating layer is 100% by volume. Is desirable. It is more preferable that it is 15% by volume or less.

Porous structures having hydrophobic parts on the surface or inside are not easily compatible with water. Among them, silica airgel has a small specific gravity, so it easily floats on water. Therefore, it is difficult to disperse silica airgel in a binder solution using water as a solvent, and the dispersion step takes time. Further, even if a heat insulating paint is prepared, there is a problem that the silica airgel separates from water and easily floats. In addition, if pressure is applied to the heat insulating paint, it may separate, making it difficult to apply with a coating machine, making it unsuitable for continuous production.

In order to solve such a problem, it is desirable that the second heat insulating layer has a polysaccharide in addition to the porous structure and the second aqueous binder. Polysaccharides are glycosidic bonds of one or more monosaccharides and have high viscosity. When a porous structure is added to a binder solution in which a secondary aqueous binder is dissolved or dispersed in water to prepare a heat insulating paint, when a polysaccharide is added, the viscosity of the heat insulating paint becomes high, and the porous structure is formed from the binder liquid. Is difficult to separate. Therefore, the dispersibility of the porous structure is improved, and the porous structure can be stably held in the heat insulating paint. Further, when the viscosity of the heat insulating paint becomes high, it becomes difficult for the heat insulating paint to drip, so that it is easy to apply the heat insulating paint. Polysaccharides suppress the separation of porous structures by thickening due to the entanglement of molecular chains. Therefore, even if a polysaccharide is blended, a heat transfer path is not easily formed and the heat insulating property is not easily deteriorated.

For example, when a polysaccharide having both a hydrophilic part and a hydrophobic part is blended, the hydrophobic part is selectively bound to the hydrophobic part of the porous structure, and the hydrophilic part is arranged so as to surround the porous structure. As a result, it becomes a state like a protective colloid. This action also suppresses the separation of the binder liquid and the porous structure, and improves the dispersibility of the porous structure. As a result, the time required for dispersion can be shortened, and it becomes easy to make a paint. In addition, polysaccharides having hydrophilic sites do not easily penetrate into the pores of the hydrophobic porous structure.

Examples of the polysaccharide include carboxylmethyl cellulose, carboxyethyl cellulose, carboxypropyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, xanthan gum, agarose, carrageenan and the like. Among them, those having a long main chain and no or short side chains have more entanglement of molecular chains. As a result, the retention of the porous structure is enhanced, so that the loss of the porous structure in the second heat insulating layer can be suppressed. For example, carboxymethyl cellulose is suitable.

As described above, the second heat insulating layer may contain other components (additives) such as a cross-linking agent and a polysaccharide in addition to the porous structure and the second aqueous binder.

Considering the heat insulating property, the thickness of the second heat insulating layer is preferably 0.3 mm or more, more preferably 0.5 mm or more. On the other hand, if the second heat insulating layer is too thick, not only the cost is high, but also the strength is lowered and the second heat insulating layer becomes brittle. Therefore, it is desirable that the thickness of the second heat insulating layer break is 1 mm or less, more preferably 0.7 mm or less. When the first heat insulating layer is made of a material having voids, a part of the second heat insulating layer may be impregnated into the first heat insulating layer. By impregnating, the adhesiveness of both layers is improved. However, if the impregnation depth becomes large, heat transfer due to convection in the first heat insulating layer may be hindered. Therefore, the impregnation depth is only the surface layer portion of the first heat insulating layer, for example, 0.1 mm or more. It should be about 5 mm or less.

(3) Heat-reflecting layer The heat-reflecting layer is laminated on the second heat insulating layer. From the viewpoint of improving the heat insulating property, it is desirable that the reflectance of the heat reflecting layer is 80% or more in the region where the wavelength of the incident light is 780 nm or more and 2500 nm or less (near infrared region). The reflectance of the heat-reflecting layer may be measured by a UV-VIS ultraviolet-visible spectrophotometer "Solid Spec-3700" manufactured by Shimadzu Corporation.

The material of the heat-reflecting layer is not particularly limited, but it is desirable to have a metal layer from the viewpoint of achieving a desired reflectance. Suitable metals include aluminum, aluminum compounds, magnesium, magnesium compounds, stainless steel, silver, titanium, titanium compounds, tin and the like. Examples of the form of the metal layer include a metal foil and a vapor-deposited film. In the latter case, for example, a metal may be vapor-deposited on the surface of a resin film made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide, polyethylene (PE) or the like by vacuum vapor deposition or sputtering. In this case, the heat-reflecting layer is in the form of having a metal layer (deposited film) and a resin layer (resin film) laminated on the metal layer (so-called vapor-deposited film). Not limited to the vapor-filmed film, when the heat-reflecting layer is composed of a metal layer and a resin layer, which of the metal layer and the resin layer is arranged on the second heat insulating layer side depends on the adhesive component in the flame-retardant adhesive layer and heat insulating. It may be appropriately determined in consideration of the usage pattern of the member and the like. That is, the resin layer may be arranged on the second heat insulating layer side, or the metal layer may be arranged on the second heat insulating layer side. Further, from the viewpoint of suppressing corrosion and protecting the vapor-deposited film, the vapor-filmed film may be further coated with a resin layer.

From the viewpoint of strength, it is desirable that the thickness of the heat reflecting layer is 0.01 mm or more, more preferably 0.02 mm or more. On the other hand, from the viewpoint of flexibility, the thickness of the heat reflecting layer is preferably 0.05 mm or less, more preferably 0.03 mm or less.

The heat-reflecting layer is adhered to the second heat insulating layer by the flame-retardant adhesive layer. From the viewpoint of improving the durability of the heat insulating member, it is desirable that the peeling force of the heat reflecting layer with respect to the second heat insulating layer is 0.1 N / 25 mm or more. It is more preferable that it is 0.8 N / 25 mm or more, more preferably 1.0 N / 25 mm or more. In the present specification, the peeling force of the heat reflective layer is subjected to a 180 ° peeling test according to "10.4 Measurement of peeling adhesive strength" of JIS Z0237: 2009, and the peeling length is 50 mm from 25 mm to 75 mm. The average value of the peeling force measurement values of the minute is adopted. The 180 ° peeling test shall be performed at room temperature under the conditions of a tensile width of 25 mm, a tensile distance of 80 mm or more, and a tensile speed of 100 mm / min.

(4) Flame-retardant adhesive layer The flame-retardant adhesive layer is arranged between the second heat insulating layer and the heat-reflecting layer, and adheres both layers. The flame-retardant adhesive layer may have a continuous form, an intermittent form, or an island-like scattered form as long as a desired adhesive force can be achieved. The thickness of the flame-retardant adhesive layer may be uniform or non-uniform, and is preferably 0.01 mm or more, for example. On the other hand, in consideration of maintaining the adhesive force against the shearing force and flexibility, the thickness of the flame-retardant adhesive layer is preferably 0.05 mm or less.

The flame-retardant adhesive layer has an adhesive component and a flame retardant. The adhesive component may be appropriately selected in consideration of the materials of the heat reflecting layer and the second heat insulating layer. For example, it is desirable to use a first aqueous binder using water as a solvent from the viewpoint that it is difficult to penetrate into the pores of the hydrophobic porous structure contained in the second heat insulating layer. The first aqueous binder is the same as the second aqueous binder described above. That is, the first aqueous binder includes a water-soluble binder and an emulsion-like binder, and an emulsion-like binder (aqueous emulsion-based binder) is suitable. Further, the binder component may be resin or rubber. Examples of the resin include acrylic resin, urethane resin, and a mixture of acrylic resin and urethane resin. Examples of the rubber include SBR, nitrile rubber, silicone rubber, urethane rubber, acrylic rubber and the like. A cross-linking agent or the like may be used in combination as the adhesive component to cross-link the binder component. The first water-based binder may be the same as or different from the second water-based binder contained in the second heat insulating layer, but if it is the same as the second water-based binder, it is easily compatible with the second heat insulating layer and the adhesiveness is improved.

The flame retardant may be a halogen-based, phosphorus-based, metal hydroxide-based, or other already known flame retardant, and is not particularly limited. Considering the environmental load, it is desirable to use a phosphorus flame retardant. Examples of the phosphorus-based flame retardant include ammonium polyphosphate, red phosphorus, and a phosphoric acid ester. Among them, those that are insoluble in water are desirable because the flame retardant does not easily flow out even if they come into contact with water during use, and for example, ammonium polyphosphate is preferable.

For example, when a powdered flame retardant is dispersed in a binder liquid using water as a solvent, aggregation of the flame retardant may become a problem. In this case, it is effective to suppress aggregation if the particle surface is coated with a resin or the like. When the aggregation is suppressed, a stable dispersed state can be obtained, and when the adhesive paint is applied by spraying or the like, problems such as clogging are less likely to occur. For example, in the case of ammonium polyphosphate, particles coated with a melamine resin may be mentioned.

The content of the flame retardant in the flame-retardant adhesive layer may be appropriately determined in consideration of the balance between flame retardancy and adhesiveness. For example, from the viewpoint of enhancing flame retardancy, the content of the flame retardant is preferably 50% by mass or more when the entire flame retardant adhesive layer is 100% by mass. It is more preferable that the content is 60% by mass or more, more preferably 80% by mass or more. On the other hand, the higher the content of the flame retardant, the lower the adhesiveness. Therefore, considering the adhesiveness, it is desirable that the content of the flame retardant is 90% by mass or less, more preferably 85% by mass or less. The flame-retardant adhesive layer may contain other components (additives) such as a dispersant in addition to the adhesive component and the flame retardant.

(5) Other configurations As long as the heat insulating member of the present invention has the above-mentioned four layers, other configurations are not limited. For example, as shown in the second embodiment, the heat insulating member of the present invention may further include a member for fixing to a mating member such as an adhesive sheet. Examples of such a fixing member include an adhesive layer coated with an adhesive, fasteners such as pins, and thread-like members for sewing. In the second embodiment, the adhesive sheet is arranged on the first heat insulating layer side, but this kind of fixing member may be arranged on the heat reflecting layer side. When the adhesive sheet is used, its composition, thickness and the like are not particularly limited. For example, the pressure-sensitive adhesive may be appropriately selected from acrylic type, silicone type, rubber type and the like. The release paper may also have a base material made of a resin film instead of paper.

[Manufacturing method of heat insulating member]
(1) The first manufacturing method of the present invention, which is one of the preferred manufacturing methods of the heat insulating member of the present invention, includes a heat insulating paint coating step, an adhesive paint coating step, and a curing step. Hereinafter, each step will be described.

(A) Insulation paint coating process This step is a step of applying a heat insulating paint having a porous structure and a second water-based binder to the first heat insulating layer to form a coating film. The heat insulating paint may be prepared by dispersing and dissolving a material (a porous structure, an additive such as a second aqueous binder, a polysaccharide, etc.) for forming the second heat insulating layer in water. Each material is as described above. When a polysaccharide is blended in consideration of the dispersibility of the porous structure, it is advisable to add a secondary aqueous binder and the polysaccharide to water to increase the viscosity of the liquid, and then add the porous structure.

To apply the heat insulating paint, brush coating, a coating machine such as a blade coater, a bar coater, a die coater, a comma coater (registered trademark), a roll coater, or a spray may be used. For example, according to the blade coating method, it is suitable because it can be applied with a uniform thickness. When the first heat insulating layer is made of cloth or a porous material, a part of the applied heat insulating paint impregnates the surface layer portion of the first heat insulating layer.

(B) Adhesive paint application step This step is a step of applying an adhesive paint having an adhesive component and a flame retardant to the heat reflective layer to form a coating film. The adhesive coating material may be prepared by dispersing and dissolving a material (adhesive component, an additive such as a flame retardant, a dispersant, etc.) for forming a flame-retardant adhesive layer in water. Each material is as described above. In order to apply the adhesive paint, as in the case of applying the heat insulating paint, brush painting, various coating machines, sprays, etc. may be used.

(C) Curing step In this step, the first heat insulating layer and the heat reflecting layer are superposed so that the formed coating films are in contact with each other, and the two coating films are cured to bond the second heat insulating layer and the flame-retardant adhesive. This is the process of forming a layer. In order to superimpose the first heat insulating layer and the heat reflecting layer, for example, a roll laminating device or the like may be used to pressurize the layer. Then, the obtained laminate may be held at a temperature of 80 to 150 ° C. for several minutes to several tens of minutes and dried to cure the coating film.

(2) The second manufacturing method of the present invention, which is one of the preferred manufacturing methods of the heat insulating member of the present invention, includes a heat insulating paint coating step, an adhesive paint coating step, and a curing step. The second manufacturing method is different from the first manufacturing method in that, in the adhesive paint application step, the adhesive paint is applied on the surface of the coating film of the heat insulating paint formed on the first heat insulating layer instead of the heat reflecting layer. different. Since the heat insulating paint application process is the same as the first manufacturing method, the description thereof will be omitted, and only the adhesive paint application process and the curing process will be described below.

(A) Adhesive paint application step This step is a step of applying an adhesive paint having an adhesive component and a flame retardant to the surface of the heat insulating paint coating film formed on the first heat insulating layer to form an adhesive paint coating film. be. The method for preparing the adhesive paint is the same as the first manufacturing method. In this step, it is necessary to apply the adhesive paint to the surface of the coating film of the heat insulating paint in a wet state, so it is desirable to spray the adhesive paint using a spray or the like.

(B) Curing Step In this step, the heat reflective layer is superposed on the coating film of the adhesive paint in the first heat insulating layer, and the two coating films of the heat insulating paint and the adhesive paint are cured to form the second heat insulating layer and the flame-retardant adhesive layer. Is the process of forming. In this step as well, as in the first manufacturing method, it is preferable to superimpose the first heat insulating layer and the heat reflecting layer while applying pressure using a roll type laminating device or the like. Then, the obtained laminate may be held at a temperature of 80 to 150 ° C. for several minutes to several tens of minutes and dried to cure the coating film.

Next, the present invention will be described in more detail with reference to examples. Here, five heat insulating member samples were manufactured by the first manufacturing method of the present invention, and the adhesiveness of the heat reflecting layer, the heat insulating property of the heat insulating member, and the flame retardancy were evaluated.

<Manufacturing of heat insulating member samples>
[Example 1]
(1) Preparation of heat insulating paint A heat insulating paint for forming the second heat insulating layer was prepared as follows. Urethane resin emulsion as a second aqueous binder ("Permarin (registered trademark) UA-368" manufactured by Sanyo Chemical Industries, Ltd., solid content 50% by mass) and carboxylmethyl cellulose as a polysaccharide (CMC: molecular weight 38) are added to water. , And while stirring with a stirring blade, silica airgel having hydrophobic sites on the surface and inside (average particle diameter 90 μm, central pore diameter 30 nm, density 0.11 g / cm ³ ) was added. The blending ratio of each component was 75.06% by mass of water, 14.00% by mass of urethane resin emulsion, 0.32% by mass of CMC, and 10.62% by mass of silica airgel. The silica airgel was produced as follows according to the method described in paragraphs [0102] to [0106] of Japanese Patent No. 5250900.

First, a surfactant and urea were added to an aqueous acetic acid solution and dissolved. Next, methyltrimethoxysilane (MTMS) was added with stirring. The molar ratio at this time was MTMS: water: acetic acid: urea = 1: 15.9: 0.0860 (5 mM): 1.43. Subsequently, after stirring this mixed solution at room temperature for 30 minutes, the mixture was placed in a closed container and allowed to stand at 60 ° C. for 3 days for gelation and aging. Then, the obtained wet gel was immersed in methanol at 60 ° C. for 8 hours for washing. Washing was performed 3 times in total. Subsequently, the washed wet gel was immersed in hexane at 55 ° C. for 8 hours to exchange the solvent. The solvent exchange was performed twice in total. The solvent-replaced wet gel was then air dried overnight in the air and dried in an oven at 100 ° C. until no weight change. In this way, a silica airgel having hydrophobic sites on the surface and inside was obtained. The obtained silica airgel was pulverized with a pulverizer until the particle size became about 90 μm before use.

(2) Preparation of Adhesive Paint An adhesive paint for forming a flame-retardant adhesive layer was prepared as follows. A urethane resin emulsion (same as above) as a first aqueous binder and a melamine resin coated type of ammonium polyphosphate as a phosphorus-based flame retardant ("Terage (registered trademark) C-30" manufactured by Budenheim Co., Ltd.) are added to water. The mixture was stirred with a stirring blade. The mixing ratio of each component was 32.8% by mass of water, 23.5% by mass of urethane resin emulsion, and 43.7% by mass of ammonium polyphosphate.

(3) Aluminum-deposited film As a heat-reflecting layer, an aluminum-deposited film (“Metal Me (registered trademark) S # 25” manufactured by Toray Film Processing Co., Ltd., thickness 0.025 mm) was prepared. The structure of this aluminum-deposited film is the same as that of the heat-reflecting layer of the first embodiment (“PET film / aluminum-deposited film”). Then, the prepared aluminum vapor-deposited film reflectance was measured by a UV-VIS ultraviolet-visible spectrophotometer "Solid Spec-3700" manufactured by Shimadzu Corporation. The measurement wavelength range was 300 to 2500 nm. FIG. 5 is a graph showing the measurement result of the reflectance. As shown in FIG. 5, it was confirmed that the reflectance of the aluminum-deposited film was 80% or more in the region where the wavelength of the incident light was 780 nm or more and 2500 nm or less.

(4) Manufacturing process The prepared heat insulating paint was applied to the surface of the non-woven fabric (grain size 65 g / m ² , thickness 1.0 mm) as the first heat insulating layer by the blade coating method to form a coating film (heat insulating paint). Coating process). Further, an adhesive paint was applied to the surface of the aluminum-deposited film on the PET film side by a spray coating method to form a coating film (adhesive paint application step). Next, the non-woven fabric and the aluminum-deposited film were laminated so that the coating films of each other were in contact with each other while being pressurized using a roll-type laminating device. Then, the obtained laminate is dried at 150 ° C. for 5 minutes to cure the two coating films, and heat insulation composed of four layers of a first heat insulating layer / a second heat insulating layer / a flame-retardant adhesive layer / a heat reflecting layer. A member sample was manufactured (curing step). The heat insulating member sample thus produced is referred to as a sample of Example 1. FIG. 6 shows a cross-sectional view of the sample of Example 1 in the thickness direction.

As shown in FIG. 6, the sample 40 of Example 1 has a rectangular thin sheet shape. The sample 40 is formed by laminating a first heat insulating layer 41, a second heat insulating layer 42, a flame-retardant adhesive layer 43, and a heat reflecting layer 44 in this order from the bottom. The thickness of the first heat insulating layer 41 is 1.0 mm, the thickness of the second heat insulating layer 42 is 0.5 mm, the impregnation depth of the second heat insulating layer 42 in the first heat insulating layer 41 is 0.1 mm, and the flame-retardant adhesive layer. The thickness of 43 is 0.03 mm, the thickness of the heat reflecting layer 44 is 0.025 mm, and the thickness of the entire sample 40 is 1.455 mm.

The content of silica airgel in the second heat insulating layer of the sample of Example 1 is 95% by volume, and the content of the second aqueous binder is 4.2% by volume. The content of the first aqueous binder in the flame-retardant adhesive layer is 20% by mass, and the content of the flame retardant is 80% by mass.

[Examples 2 to 5]
Examples 2 to 2 in the same manner as in Example 1 above, except that the blending ratio of each component in the adhesive paint was changed and the contents of the first water-based binder and the flame retardant in the manufactured flame-retardant adhesive layer were changed. 5 samples were produced. The contents of the first aqueous binder and the flame retardant in each sample are summarized in Table 1 below.

[Comparative Example 1]
For comparison, a heat insulating member sample without a flame-retardant adhesive layer was manufactured. First, the same heat insulating paint as in Example 1 was applied to the surface of the nonwoven fabric (same as above) as the first heat insulating layer by the blade coating method to form a coating film. Next, an aluminum-deposited film (same as above) as a heat-reflecting layer was laminated on the surface of the coating film of the non-woven fabric while applying pressure using a roll-type laminating device. Then, the obtained laminate was dried at 150 ° C. for 5 minutes to cure the coating film, and a heat insulating member sample composed of three layers of a first heat insulating layer / a second heat insulating layer / a heat reflecting layer was produced. The first heat insulating layer and the second heat insulating layer, and the second heat insulating layer and the heat reflecting layer are each adhered by a second water-based binder (urethane resin) contained in the second heat insulating layer. In the heat insulating member sample, the thickness of the first heat insulating layer is 1.0 mm, the thickness of the second heat insulating layer is 0.5 mm, the impregnation depth of the second heat insulating layer in the first heat insulating layer is 0.1 mm, and the heat reflecting layer. The thickness of the sample is 0.025 mm, and the thickness of the entire sample is 1.425 mm. The heat insulating member sample thus produced is referred to as a sample of Comparative Example 1.

[Comparative Example 2]
In the same manner as in Comparative Example 1 above, Comparative Example 2 except that the mixing ratio of each component in the heat insulating paint was changed and the contents of the silica airgel and the second aqueous binder in the produced second heat insulating layer were changed. A sample was produced. The content of silica airgel in the second heat insulating layer of the sample of Comparative Example 2 is 90% by volume, and the content of the second aqueous binder is 9.6% by volume. Table 1 summarizes the composition of each sample and the evaluation results of adhesiveness, heat insulating property, and flame retardancy, which will be described later.

<Adhesion evaluation>
The peeling force of the heat-reflecting layer (aluminum-deposited film) with respect to the second heat insulating layer was measured to evaluate the adhesiveness of the heat-reflecting layer.

[Peeling test]
A 180 ° peeling test was performed according to "10.4 Measurement of Peeling Adhesive Strength" of JIS Z0237: 2009. The 180 ° peeling test was performed at room temperature under the conditions of a tensile width of 25 mm, a tensile distance of 80 mm or more, and a tensile speed of 100 mm / min. The average peeling force was calculated by ignoring the measured values from the start of peeling to 25 mm and averaging the measured values for the length of 50 mm thereafter. When the average peeling force is 1.0 N / 25 mm or more, the adhesiveness is good (indicated by ◯ in Table 1), and when the average peeling force is 0.1 N / 25 mm or more and less than 1.0 N / 25 mm, the adhesiveness is good. It was evaluated as slightly defective (indicated by a triangle in the table).

[result]
As shown in Table 1, in each of the samples of Examples 1 to 4, it was confirmed that the average peeling force was 1.0 N / 25 mm or more, and the adhesiveness of the heat reflecting layer was high. It was also confirmed that the average peeling force increased as the content of the first aqueous binder in the flame-retardant adhesive layer increased, and the adhesiveness improved. In addition, since the content of the first aqueous binder was small in the sample of Example 5, the adhesiveness was slightly lowered as compared with the samples of other Examples. Further, in the sample of Comparative Example 1 having no flame-retardant adhesive layer, the average peeling force was small, and the adhesiveness was lowered as compared with the other Example samples. The sample of Comparative Example 2 also did not have a flame-retardant adhesive layer, but the adhesiveness was improved by increasing the content of the second aqueous binder in the second heat insulating layer. However, as will be described later, the content of silica airgel in the second heat insulating layer is reduced, so that the heat insulating property is lowered.

<Insulation evaluation>
The heat insulating property of each sample was evaluated based on the heat loss reduction rate calculated in the following experiment.

[Experimental equipment and method]
First, the configuration of the experimental device will be described. FIG. 7 shows a schematic diagram of the experimental device. As shown in FIG. 7, the experimental apparatus 8 includes a heat insulating box 80, a lid 81, an air heating heater 82, a heater controller 83, and a first thermocouple 84. The heat insulating box 80 and the lid 81 are manufactured by attaching a phenol foam heat insulating material (“Neomafoam (registered trademark)” manufactured by Asahi Kasei Construction Materials Co., Ltd.) having a thickness of 40 mm as a wall material to an aluminum frame. The inner dimensions of the heat insulating box 80 are 215 mm in length, 350 mm in width, and 150 mm in height. An opening 801 for installing a sample is formed in the upper wall portion 800 of the heat insulating box 80. The size of the opening 801 is 140 mm in length and 220 mm in width. Similarly, an opening is also formed in the central portion of the lid portion 81, and the steel plate 810 is arranged in the opening. The lid 81 is removable from the heat insulating box 80. The air heating heater 82 and the first thermocouple 84 are arranged inside the heat insulating box 80. The first thermocouple 84 is arranged to measure the temperature of the space above the air heating heater 82. The heater controller 83 is arranged outside the heat insulating box 80 and is electrically connected to the air heating heater 82.

Next, the experimental method will be described. First, a polypropylene (PP) base material 45 was prepared and placed on the upper surface of the upper wall portion 800 so as to close the opening 801. Next, the sample 40 (see FIG. 6 above) was placed on the upper surface of the base material 45. The sample 40 was arranged with the first heat insulating layer 41 on the lower side (base material 45 side). Then, a second thermocouple 85 was attached so as to measure the temperature of the space above the sample 40. Finally, the upper wall portion 800 was covered with the lid portion 81 so as to surround the base material 45 and the sample 40.

The inside of the heat insulating box 80 was heated by the air heating heater 82 in an environment of an outside air temperature of 24 ° C. At this time, the temperature inside the heat insulating box 80 was controlled to be 80 ° C. by the heater controller 83. The temperature inside the heat insulating box 80 was measured by the first thermocouple 84. From the start of heating to 50 minutes after the temperature inside the heat insulating box 80 became 80 ° C. and stabilized (total 100 minutes), the temperature of the upper space of the sample 40 was measured by the second thermocouple 85.

Separately, only the base material 45 was placed on the upper wall portion 800 of the heat insulating box 80. Then, the inside of the heat insulating box 80 was heated under the same conditions, and the temperature of the upper space of the base material 45 for 100 minutes from the start of heating was measured by the second thermocouple 85.

[Experimental result]
As an example of the experimental results, FIG. 8 is a graph showing the temperature inside the heat insulating box, the upper space temperature of the sample of Example 1, and the change with time of room temperature. FIG. 8 also shows the upper space temperature of the base material when only the base material is arranged for comparison. As shown in FIG. 8, it can be seen that the upper space temperature is suppressed to be lower when the sample is laminated on the base material than when the base material is used alone. That is, it can be seen that the heat transfer from the inside of the heat insulating box to the outside is suppressed by arranging the heat insulating member. The heat insulating property was evaluated based on the amount of change in the upper space temperature of the sample calculated by the following method.

First, the average value of the upper space temperature of the sample was calculated for 50 minutes (specifically, from 50 minutes to 100 minutes after the start of the experiment) after the temperature in the heat insulating box became 80 ° C. and stabilized. Next, the average value of the room temperature for 50 minutes was calculated, and the average value of the room temperature was subtracted from the average value of the upper space temperature of the sample to obtain the amount of change in the upper space temperature of the sample. In the same way, the amount of change in the upper space temperature of the base material when only the base material was placed was also calculated. Then, the heat loss reduction rate was calculated by the following equation (i) based on the amount of change in the upper space temperature of the base material and the amount of change in the upper space temperature of the sample.
Heat loss reduction rate (%) = (ΔT ₀ − ΔT) / ΔT ₀ × 100 ・ ・ ・ (i)
[In the formula, ΔT ₀ : change in the upper space temperature of the base material, ΔT: change in the upper space temperature of the sample]
Based on the obtained value of the heat loss reduction rate, the heat insulating property was evaluated in three stages of high, medium, and low. That is, when the heat loss reduction rate is 35% or more, the heat insulating property is "high" (indicated by a circle in Table 1), and when the heat loss reduction rate is 25% or more and less than 35%, the heat insulating property is "medium" (same as above). In the table, indicated by Δ), when the heat loss reduction rate was less than 25%, the heat insulating property was evaluated as “low”.

As shown in Table 1, in each of the samples of Examples 1 to 5, it was confirmed that the heat loss reduction rate was 35% or more, and the amount of heat flowing out could be significantly reduced. That is, it was confirmed that the heat insulating member of the present invention has excellent heat insulating properties. On the other hand, in the sample of Comparative Example 2, the content of silica airgel decreased by the amount that the content of the second aqueous binder in the second heat insulating layer was increased in order to enhance the adhesiveness. As a result, when the sample of Comparative Example 2 was used, the heat insulating property was lowered as compared with the case where the other samples were used. As described above, according to the heat insulating member of the present invention, it is possible to achieve both high adhesiveness and high heat insulating property.

<Flame retardance evaluation>
The flame retardancy of each sample was evaluated based on the US Federal Motor Vehicle Safety Standard "FMVSS No. 302" (ISO 3795, JIS D 1201), which is a combustion test of automobile interior materials.

[Combustion test]
The produced sample was held horizontally in a U-shaped metal test piece holder, and the burning rate when a 38 mm burner flame was indirectly flamed for 15 seconds on one end side of the sample was measured. The combustion speed is measured in the combustion section of 254 mm between the A mark line and the B mark line by installing the A mark line at 38 mm from one end of the flame contact and the B mark line at 292 mm point from the same end. did. In the relevant automobile safety standard, those that meet any of the following three requirements are judged to conform to the standard. Here, 1. Or 2. Good flame retardancy (indicated by ◯ in Table 1) when the requirements of 1 are met. Or 2. Although it does not meet the requirements of 3. The case where the requirements of the above are satisfied is evaluated as a slightly defective flame retardant (indicated by a triangle in the table), and the case where none of the three requirements is satisfied is evaluated as a defective flame retardant (indicated by a cross in the table). ..
1. 1. Do not ignite the sample, or self-extinguish before the A mark (nonflammable).
2. 2. Self-extinguishing within a burning distance of 51 mm and within 60 seconds (autolytic).
3. 3. The combustion speed is 102 mm / min or less.

[result]
As shown in Table 1, it was confirmed that all the samples of Examples 1 to 5 had flame retardancy conforming to the standard of "FMVSS No. 302". In particular, a sample having a flame retardant content of 80% by mass or more in the flame retardant adhesive layer satisfied the requirement of "nonflammability" in the standard. On the other hand, the samples of Comparative Examples 1 and 2 having no flame-retardant adhesive layer did not have flame-retardant property conforming to the standard.

The heat insulating member of the present invention can be applied to various parts and members in the fields of automobiles, logistics, housing, industrial equipment, information and communication equipment, and the like. The automotive field includes interior parts such as door trims, ceiling materials, instrument panels, console boxes and armrests. The field of logistics includes heat-insulating containers used for transporting foods, pharmaceuticals, and the like. Examples of the housing field include building materials, wall materials, attics, and window sashes. In the field of industrial equipment, heat insulating members used for motor parts, sensor parts and the like can be mentioned. The field of information and communication equipment includes heat insulating members used in personal computers and smartphones. In addition to this, it is also suitable for heat insulating members for shoes such as insoles and daily necessities such as cooler boxes.

1: Door trim, 10: Insulation member, 11: First insulation layer, 12: Second insulation layer, 13: Flame-retardant adhesive layer, 14: Heat-reflecting layer, 15: Base material, 16: Skin material, 20: Insulation member , 21: Adhesive sheet, 210: Adhesive layer, 211: Release paper, 30: Insulation member, 31: Second insulation layer, 40: Sample (insulation member), 41: First insulation layer, 42: Second insulation layer, 43: Flame-retardant adhesive layer, 44: Heat-reflecting layer, 45: Base material, 8: Experimental equipment, 80: Insulation box, 81: Lid, 82: Air heating heater, 83: Heater controller, 84: First thermoelectric Pair, 85: second thermocouple, 800: upper wall part, 801: opening, 810: steel plate.

Claims (17)

With the first insulation layer,
The second heat insulating layer laminated on the first heat insulating layer and
The heat-reflecting layer laminated on the second heat insulating layer and
A flame-retardant adhesive layer that is interposed between the second heat insulating layer and the heat-reflecting layer and has an adhesive component and a flame retardant.
Equipped with
The second heat insulating layer is a porous structure in which a plurality of particles are connected to form a skeleton, has pores inside, and has a hydrophobic portion on the surface and at least on the surface, and a water-based solvent. With a dihydric binder,
The first heat insulating layer and the second heat insulating layer are adhered to each other by the second aqueous binder contained in the second heat insulating layer.
The second heat insulating layer and the heat reflecting layer are heat insulating members characterized in that they are adhered by the flame-retardant adhesive layer. The heat insulating member according to claim 1, wherein the adhesive component of the flame-retardant adhesive layer has a first aqueous binder using water as a solvent. The heat insulating member according to claim 2, wherein the first aqueous binder and the second aqueous binder are emulsion-like binders having a resin or rubber as a binder component. The heat insulating member according to claim 2 or 3, wherein the first aqueous binder and the second aqueous binder are the same. The heat insulating member according to any one of claims 1 to 4, wherein the flame retardant is a phosphorus-based flame retardant. The content of the flame retardant in the flame-retardant adhesive layer is 50% by mass or more and 85% by mass or less when the entire flame-retardant adhesive layer is taken as 100% by mass, according to any one of claims 1 to 5. Insulation member. The heat insulating member according to any one of claims 1 to 6, wherein the heat reflecting layer has a peeling force of 1.0 N / 25 mm or more with respect to the second heat insulating layer. Claims 1 to 7 that the content of the second aqueous binder in the second heat insulating layer is 4.0% by volume or more and 20% by volume or less when the whole of the second heat insulating layer is taken as 100% by volume. Insulation member according to any one of. The heat insulating member according to any one of claims 1 to 8, wherein the second heat insulating layer further contains a polysaccharide. The heat insulating member according to any one of claims 1 to 9, wherein the porous structure is a silica airgel in which a plurality of silica particles are connected to form a skeleton. The heat insulating member according to any one of claims 1 to 10, wherein the reflectance of the heat reflecting layer is 80% or more in a region where the wavelength of the incident light is 780 nm or more and 2500 nm or less. The heat insulating member according to any one of claims 1 to 11, wherein the heat reflecting layer has a metal layer. The heat insulating member according to claim 12, wherein the heat reflecting layer has a resin layer laminated on the metal layer. The heat insulating member according to claim 13, wherein in the heat reflecting layer, the resin layer is adhered to the second heat insulating layer. The heat insulating member according to any one of claims 1 to 14, wherein the first heat insulating layer is made of a non-woven fabric or a foam. The method for manufacturing a heat insulating member according to claim 1.
A heat insulating paint application step of applying a heat insulating paint having the porous structure and the second water-based binder to the first heat insulating layer to form a coating film.
An adhesive paint application step of applying an adhesive paint having the adhesive component and the flame retardant to the heat reflective layer to form a coating film,
The first heat insulating layer and the heat reflecting layer are superposed so that the formed coating films are in contact with each other, and the two coating films are cured to form the second heat insulating layer and the flame-retardant adhesive layer. Curing process and
A method for manufacturing a heat insulating member. The method for manufacturing a heat insulating member according to claim 1.
A heat insulating paint application step of applying a heat insulating paint having the porous structure and the second water-based binder to the first heat insulating layer to form a coating film of the heat insulating paint.
An adhesive paint application step of applying an adhesive paint having the adhesive component and the flame retardant to the surface of the coating film of the heat insulating paint to form a coating film of the adhesive paint.
The heat-reflecting layer is superposed on the coating film of the adhesive paint in the first heat insulating layer, and the two coating films of the heat insulating paint and the adhesive paint are cured to form the second heat insulating layer and the flame-retardant adhesive layer. And the curing process to form
A method for manufacturing a heat insulating member.

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