JP2010167685A - Heat insulation sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat insulation sheet excellent in heat insulating properties, which is lightweight and flexible, and in which a holding and winding are possible. <P>SOLUTION: A laminate solving a problem of dusting which is a defect of aerogel is provided, noting that the aerogel is lightweight and can exert excellent insulating characteristics. The laminate comprises a resin coat or an inorganic fiber cloth 2 resin-impregnated arranged on one surface of an aerogel sheet 1 in which a porosity is 80 vol.% or more, and a reinforcing sheet 3 having a heat resistance of a heatproof temperature or more of the aerogel sheet 1 on the other surface of the aerogel sheet 1. The laminate is laminated and integrated by a mechanical coupling means. The mechanical coupling means has an engaging part on both surfaces of the laminate, and is to be preferably a fastening member 4 having a penetration part penetrating the laminate, more preferably a rivet. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat-insulating sheet that is lightweight, flexible, and excellent in heat insulation, and is used for a heat-insulating curtain that prevents heat dissipation from a storage place of various cast pieces manufactured in a steelmaking factory.

  In a steelmaking factory consisting of a converter and continuous casting equipment, etc., the opening and closing part of the slab storage area is used to prevent heat dissipation from various slabs such as slabs, blooms and billets produced there. Insulating curtains are used.

  In such a heat insulating curtain, a heat insulating sheet is used to prevent energy loss due to heat dissipated from the heat source. Furthermore, it is required to have flexibility so that it can be folded and wound for ease of storage and transportation. For this reason, conventional heat-resistant materials such as ceramic mats and silica mats are not suitable for folding and winding because they are too thick and lack flexibility when it is desired to ensure a desired heat insulating effect. In addition, when conventional heat-resistant materials such as ceramic mats and silica mats are used for applications such as curtains and screens that suspend horizontal heat-insulating sheets, the weight of these materials is large, so the support structure for heat-insulating sheets is reinforced. Therefore, it is necessary to increase the size of the apparatus, which is not suitable for the trend of downsizing of the entire apparatus. Furthermore, when used outdoors, water repellency and water resistance are also required.

  Under such circumstances, Japanese Utility Model Application Laid-Open No. 60-166212 (Patent Document 1) utilizes the fact that several layers of silica cloth or ceramic cloth are used as the heat insulating layer, so that the heat insulating effect is improved for the thickness.・ Silica cloth or ceramic cloth with excellent heat resistance is used on the high-temperature part side, and this is a mat made of ceramic fiber or silica fiber with cushioning properties, and glass cloth with excellent tensile strength, bending resistance and wear resistance. A heat-insulating curtain has been proposed in which a heat-resistant metal protective material that can be bent in the winding direction is connected to one surface of a heat-insulating material that is processed and integrated by sewing. According to such a configuration, it is described that the thickness can be insulated to about 200 ° C. on the opposite surface side with respect to the heat source side of 1000 ° C. with a thickness of about 10 mm.

  In addition, the fireproof screen proposed in Japanese Patent Application Laid-Open No. 11-235393 (Patent Document 2) can satisfy the fireproof performance such that it does not emit smoke when heated, but cannot satisfy the mechanical strength. In particular, when a silicone resin is applied to the surface of silica cloth, it was made in order to solve the problem that the strength is remarkably lowered by heating. The silica fiber yarn and the reinforcing strength excellent in heat resistance by the silica fiber yarn. It is a fireproof screen made of a woven fabric woven by using a yarn (aramid fiber yarn or carbon fiber yarn) together.

  JP-A-5-311596 (Patent Document 3) discloses that a ceramic sheet using an inorganic binder has a high sheet strength and a low thermal conductivity in order to solve the problem that the adhesive strength between fibers is weak. Further, as a heat insulating material having excellent workability, a ceramic sheet in which ceramic fibers are bonded with silica gel and an organic binder has been proposed.

Japanese Utility Model Publication No. 60-166212 JP-A-11-235393 JP-A-5-311596

In the heat insulating curtain disclosed in Patent Document 1, since a plurality of heat insulating layers are used, in order to obtain a large heat insulating effect, it is necessary to increase the thickness, and flexibility and weight reduction cannot be satisfied.
Further, the fireproof screen disclosed in Japanese Patent Application Laid-Open No. 11-235393 needs to be woven so as not to be misaligned in order to sufficiently exhibit the heat insulating effect and the heat resistant effect. In addition, since indoor heat insulation sheets such as fireproof screens are assumed, heat insulation sheets for outdoor use that are exposed to rainwater (for example, heat insulation curtains used for outdoor storage of cast slabs and blocking sheets to be attached to roofs and vehicle ceilings) ) Cannot be used.
Furthermore, since the heat insulating sheet disclosed in JP-A-5-311596 lacks flexibility, it is used as a heat insulating material having a specification mode in which winding and unwinding are repeated, that is, a heat insulating curtain, a fireproof screen, and a shielding sheet. I can't.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a heat insulating sheet that is lightweight, flexible and capable of being folded and wound, and excellent in heat insulating properties. There is to do.

  As a result of various studies on a heat insulating material that is lightweight and flexible and can be folded and wound, the present inventors have found that airgel has a density slightly heavier than air and is lightweight. We focused on being able to demonstrate excellent heat insulation properties.

On the other hand, airgel has a cluster structure in which fine particles are fused, and is brittle and fragile. In particular, there is a problem of dust generation that airgel powder particles are released like dust when folded (for example, (See paragraph number 0009 of Table 2004-517222).
Further, in order to increase the mechanical strength of the airgel, there are proposed airgel sheets in which reinforcing fibers are dispersed in the airgel or a fibrous core material is used (Japanese translations 2007-524528, Japanese translations 2004-517222). ). However, even with an airgel sheet in which reinforcing fibers and the like are dispersed, durability is still insufficient in a specification mode such as a heat insulating curtain in which operations such as winding and unwinding are repeated.
Furthermore, no solution has yet been found for the problem of nanoparticle dust forming the airgel being released from the airgel, whether the reinforcing fiber is more reinforced or not. Currently.

  The present inventor completed the present invention as a result of further studies to provide a heat insulating sheet that can be applied to outdoor use, while solving the problem of dust generation while taking advantage of the excellent heat insulating properties of airgel. did.

  That is, the heat insulating sheet of the present invention is provided with a resin coat or a resin impregnated inorganic fiber cloth foil on one surface of an airgel sheet having a porosity of 80 vol% or more, and on the other surface of the airgel sheet, A laminated body in which a reinforcing sheet having heat resistance equal to or higher than the heat resistant temperature is provided, and the laminated body is laminated and integrated by a mechanical coupling means.

  The mechanical coupling means is preferably a fastening member having engagement portions on both sides of the laminate and a penetrating portion penetrating the laminate, and more preferably a rivet.

  The reinforcing sheet is preferably a mesh having open pores, a net, or a cloth foil, and more preferably selected from the group consisting of a metal mesh, an inorganic fiber cloth foil, and combinations thereof.

  The resin coat or resin impregnation is preferably a silicone resin coat or impregnation.

  The heat insulating sheet of the present invention is a laminate using an airgel sheet that is a lightweight and excellent heat insulating material, and the problem of dust generation of the airgel sheet is solved.

It is a schematic cross section which shows the structure of one Embodiment of the heat resistant sheet which concerns on this invention.

  Although embodiments of the present invention will be described below, it should be considered that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  In the heat insulating sheet of the present invention, a glass fiber cloth foil coated with resin on one surface of an airgel sheet having a porosity of 80 vol% or more is disposed, and on the other surface of the airgel sheet, a heat resistance higher than the heat resistance temperature of the airgel sheet is provided. It is a laminated body in which a reinforcing sheet having a property is disposed, and the laminated body is integrated by an insertion member.

<Airgel sheet>
The airgel used in the heat insulating sheet of the present invention is an open cell type porous body having a porosity of about 80 vol% or more. Such an airgel was obtained by removing the solvent by exposing the wet gel produced by the sol-gel method or the like to a temperature and pressure higher than the critical point of the solvent contained in the wet gel. Is. Specifically, it is manufactured by extracting the solvent contained in the gel from the pores of the gel porous body with liquid CO ₂ and then extracting it with supercritical CO ₂ .

The airgel obtained in this way is a porous material having open pores with pore sizes ranging from about 0.5 to 500 nanometers, and has a cluster structure in which nano-level spherical fine particles are fused. is doing.
Specifically, the bulk density is about 0.15 g / cc or less, preferably 0.03 to 0.3 g / cc, and the porosity is 80 vol% or more, preferably 95% or more. In addition, the thermal conductivity is 9 to 16 mW / m · k at 1 atmospheric pressure and 137 ° C., which is extremely low as a solid material.

  Since such airgel cannot convect air exceeding a lattice structure, it can suppress the heat transfer by a convection efficiently, and can show the outstanding heat insulation as a result.

As the aerogel, either an inorganic airgel or an organic aerogel may be used, and it may be appropriately selected depending on required heat resistance and the like. Inorganic aerogels are based on metal alkoxides and include materials such as silica, carbides and alumina. Examples of the organic airgel include carbon airgel and polymer airgel such as polyimide. Among these, silica airgel is preferably used because it has high affinity with glass fiber cloth and exhibits excellent heat resistance.
Further, for reinforcement, for example, an airgel sheet in which a reinforcing material which is a lofty fiber bat and an airgel are combined as disclosed in Japanese Patent Application Publication No. 2004-517222 may be used.

  The airgel sheet used in the present invention may be formed by a batch-type sol-gel casting method using a sheet-like fiber batt used as a reinforcing material, for example, as disclosed in JP-T-2007-524528. In addition, a low-viscosity solution of sol and a reagent (thermal catalyst or chemical catalyst) that induces gel formation are continuously mixed, and the sol is prepared at a speed that effectively causes gelation on a moving member such as a conveyor belt. May be formed by a continuous or semi-continuous sol-gel casting process.

<Resin-coated or resin-impregnated inorganic fiber cloth foil>
A resin-coated or resin-impregnated inorganic fiber cloth foil is disposed on one side of the airgel sheet.

  The above-mentioned inorganic fiber cloth is glass fiber, silica fiber, basalt fiber, inorganic fiber woven fabric, non-woven fabric, or knitted fabric such as ceramic fiber. Of these, woven fabric and non-woven fabric are preferably used.

  Such an inorganic fiber cloth foil is obtained by applying a resin to the cloth foil surface, or by immersing the inorganic fiber cloth foil in a resin solution, so that the cloth foil surface has a resin coat or cloth. The resin is impregnated in the mesh, and the gaps corresponding to the gaps between the weaves of the woven fabric, the gaps between the stitches of the knitted fabric, and the gaps between the fibers of the nonwoven fabric are sealed. Thereby, since the outermost layer on one side of the heat insulating sheet of the present invention is sealed, it is possible to prevent dust released from the airgel sheet from being released outside the heat insulating sheet. In addition, even when exposed to rainwater, etc., since it is sealed by the resin, water entry is prevented, so that water leaks into the internal space partitioned by a heat insulating sheet, when the airgel sheet alone This can be prevented even more.

  As the resin used for coating or impregnation, a fluorine-based resin such as silicone resin or polytetrafluoroethylene is used. In the case of a glass fiber cloth, it is preferable that the glass fiber cloth has an affinity for glass fiber and has a heat resistance of 200 ° C. or more, and a silicone resin is particularly preferably used. Silicone resin coats or impregnated glass fiber cloth foils are excellent in heat resistance, dust resistance and water repellency, and are also preferred from an economic standpoint.

  When the heat insulating sheet is used in the form of hanging and winding, the fiberglass used for the inorganic fiber cloth, particularly the glass fiber cloth, is not particularly limited, but has a diameter of 2 to 12 μm, preferably 6 to 6 μm. A 9 μm yarn is used. The thickness of the glass fiber cloth foil is 0.1 to 3.2 mm, preferably 0.4 to 2.0 mm.

  As a dustproof means for the airgel sheet, for example, it may be possible to coat the surface of the airgel sheet itself with a resin. An airgel sheet made of excellent silica has poor adhesion to the resin coating film, and the coating film is peeled off. Under such circumstances, it is not possible to take measures such as preventing dust generation or preventing the permeation of moisture by directly coating the airgel sheet surface with a resin. In this regard, in the heat insulating sheet of the present invention, dust generation from the airgel sheet can be prevented by the resin coated or impregnated inorganic fiber cloth provided on one side of the airgel sheet.

<Reinforcing sheet>
A reinforcing sheet is disposed on the other surface of the airgel sheet. Here, the other surface of the airgel sheet corresponds to the side exposed to the heat source side, for example, the slab side in a heat insulating curtain used in a slab storage place.

  As the reinforcing sheet, in addition to reinforcing the mechanical strength of the airgel sheet, a sheet that does not impair the flexibility of the airgel sheet and has a heat resistance equal to or higher than that of the airgel is used. Such a sheet is preferably a mesh, net, or cloth having open pores that allows heated air from a heat source to enter the airgel so as not to impair the heat insulating properties of the airgel. Specifically, a metal mesh such as stainless steel, nickel, or titanium, a glass fiber cloth foil, or a laminate obtained by combining these is used. A thickness of about 5 to 20 mm is used. When there is a high demand for mechanical strength and durability, it is preferable to use a combination sheet of glass fiber cloth and metal mesh. It is preferable that the glass fiber cloth is used so as to be laminated on the airgel.

  As the glass fiber cloth, the same one as the glass fiber cloth disposed on one surface may be used, or a different one may be used. In particular, in the case of heat insulation sheets used for slab storage locations, heat-insulating curtains for preventing heat dissipation, and fireproof screens, heat resistance of 800 ° C or higher is required, so the glass cloth used on the side opposite to the heat source side is It is preferable not to coat the surface with a normal resin coat applied to the surface because the heat resistance cannot be satisfied. On the other hand, when the side corresponding to the heat source side is the outside side as in the case of the heat shield sheet, it is preferable that the surface is coated with a surface resin from the viewpoint of dust prevention.

<Insulation sheet>
The structure of one embodiment of the heat insulating sheet of the present invention is shown in FIG. The heat insulating sheet shown in FIG. 1 has an airgel sheet 1 as described above provided with a resin coat or resin impregnated inorganic fiber cloth 2 and a reinforcing sheet 3 provided on the other surface. The laminated body is laminated and integrated by a fastening member 4 penetrating the laminated body 3.

  As the fastening member, a member having engaging portions on both surfaces of the laminate and an insertion portion through which the laminate is inserted is used. Specifically, a rivet is preferably used. The rivet has a head at the tip of the body portion of the round bar. After the laminated body is penetrated, the laminated body can be fastened by crushing the head portion. The shape of the rivet head is not particularly limited, and any of round rivets, flat rivets, thin flat rivets, pan rivets, flat rivets, round flat rivets and the like may be used.

  One rivet may be inserted per 60 cm × 60 cm square, preferably one per 30 cm × 30 cm square. This level is sufficient for the integration of the laminate, and the impact applied to the airgel sheet is small, and the porous structure of the airgel sheet is hardly affected.

  In addition, the member used for integration of the laminated body is not limited to the fastening member as used in the above embodiment, and a sandwiching member having engaging portions on both surfaces of the laminated body can be used. Mechanical coupling means that does not use a member, such as sewing and needle punching, may be used. Since airgel sheets are extremely poor in adhesion, integration by chemical bonding using a binder is inappropriate, but bonding integration using a fastening member, a clamping member, etc., and the physical properties of each member constituting the laminate Depending on the target entanglement, it is possible to combine them.

  However, since the airgel sheet has a very high hardness, a method of increasing the number of insertions of the airgel sheet, such as sewing or needle punching, requires a device for improving workability. In addition, in the case of the method of sandwiching the edge or corner of the laminate with the sandwiching member, if the sandwiching member itself does not have the thermal insulation performance of the airgel, the heat on the heat source side is thermally conducted to the opposite surface, It is necessary to devise the structure and material of the holding member. In this regard, in the case of a fastening member having an insertion portion that passes through the inside of the airgel sheet, such as a rivet, since the heat insulation effect by the airgel is obtained, heat conduction to the opposite surface through the insertion portion is small. Furthermore, since the fastening member is attached at a rate of one per 60 cm × 60 cm square as described above, there is almost no influence of heat insulation inhibition by the fastening member.

The heat insulating sheet having the above configuration has heat resistance to a heat source of about 700 to 900 ° C. based on the excellent heat insulating property of the airgel sheet, and can be reduced to about 60 to 150 ° C. on the opposite side. Insulation effect can be demonstrated.
In addition, since it is as thin as 5 to 15 mm and excellent in flexibility, it can be folded and wound up and stored compactly when not transported or used. Furthermore, since it is very light, it can be used in a suspended type.
In addition, the airgel sheet on the surface opposite to the heat source is sealed by a resin coat or impregnated inorganic fiber cloth, which may cause problems of dust generation and water leakage when exposed to rainwater. There is no problem. Therefore, when used for heat-resistant curtains such as slab storage, it can effectively prevent heat dissipation even outdoors where there is a risk of being exposed to rainwater, heat resistance, dust resistance, water repellency, Furthermore, it is useful from an economic point of view, and can be used not only as a part corresponding to a side wall or a hanging type but also as a awning.

  The heat insulating sheet of the present invention is lightweight, flexible, durable, excellent in heat insulation, and has no problem of dust generation due to the airgel sheet, so that it can be applied both indoors and outdoors, fireproof screen, It can be used for a heat shielding sheet.

1 Airgel sheet 2 Cloth made of inorganic fiber 3 Reinforcing sheet 4 Fastening member

Claims (6)

A surface of an airgel sheet having a porosity of 80 vol% or more is provided with a resin coat or a resin-impregnated inorganic fiber cloth foil,
On the other surface of the airgel sheet is a laminate in which a reinforcing sheet having heat resistance equal to or higher than the heat resistant temperature of the airgel sheet is disposed,
The laminate is a heat-resistant sheet that is laminated and integrated by a mechanical coupling means. 2. The heat-resistant sheet according to claim 1, wherein the mechanical coupling means is a fastening member having engaging portions on both surfaces of the laminate and a penetrating portion penetrating the laminate. The heat-resistant sheet according to claim 2, wherein the fastening member is a rivet. The heat-resistant sheet according to any one of claims 1 to 3, wherein the reinforcing sheet is a mesh, net, or cloth having open pores. The heat-resistant sheet according to any one of claims 1 to 3, wherein the reinforcing sheet is selected from the group consisting of metal foil, glass fiber cloth foil, and combinations thereof. The heat-resistant sheet according to claim 1, wherein the resin coat or resin impregnation is a silicone resin coat or impregnation.

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